BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to an azimuth propeller device. More specifically,
               the present invention relates to an azimuth propeller device which may be attached
               to the bottom of a ship to drive and steer the ship.
 
            Description of Related Art
[0002] In general, a conventional ship is provided with a propeller and a rudder separately
               provided with the propeller, which are attached to the stern of the ship so that the
               driving force for the ship is exerted by the propeller, and operations, such as turning
               of the ship, are performed by the rudder.
 
            [0003] Recently, however, the propeller used for driving the ship and the rudder used for
               operating the ship are integrated, and an azimuth propeller device, simply called
               an azimuth propeller, which is attached to the ship to be rotatable in the vertical
               direction of the ship, has been developed.
 
            [0004] The structure of a conventional azimuth propeller device will be briefly described
               with reference to FIGS. 12 and 13A and 13B. FIG. 12 is a schematic diagram showing
               an attachment of an azimuth propeller device at the stern portion of a ship. FIG.
               13A is a diagram showing the right hand side view of the azimuth propeller device.
               FIG. 13B is a diagram showing a cross-sectional view of the azimuth propeller device
               shown in FIG. 13A taken along the line F-F. In the figures, the numeral 1 indicates
               a rear portion of the ship's bottom, 2 indicates an azimuth pod, 3 indicates a shaft,
               4 indicates a current plate member, 5 indicates a propeller member, and 10 indicates
               an azimuth propeller device.
 
            [0005] As shown in the figures, the azimuth propeller device 10 is rotatably attached to
               the rear portion of the ship's bottom 1 via the shaft 3. The azimuth propeller device
               10 includes the propeller member 5, the azimuth pod 2, and the current plate member
               4. The propeller member 5, which exerts the driving force for the ship, may be attached
               to the front or back of the azimuth device 10. The azimuth pod 2 accommodates a propeller
               drive mechanism (not shown in the figures) in the inside thereof. The current plate
               member 4 is integrally fixed to the upper portion of the azimuth pod 2 and has a streamline
               cross sectional shape. The current plate member 4 is attached to the lower portion
               of the shaft 3 which extends in the vertical direction, and the upper portion of the
               shaft 3 is coupled with a driving mechanism (not shown in the figures), which is disposed
               in the hull so that the shaft 3, the current plate member 4, the azimuth pod 2, and
               the propeller member 5 are integrally rotated.
 
            [0006] By using the azimuth propeller device 10 having the above described structure, it
               becomes possible to drive the ship using the driving force generated by rotating the
               propeller member 5, and to obtain steering function by rotating the azimuth propeller
               device 10 with respect to the rear portion of the ship's bottom 1 to change the travelling
               course of the ship. Note that a motor used for outputting the driving force for the
               propeller member 5 may be disposed in the azimuth pod 2 or in the hull of the ship.
 
            [0007] In the conventional azimuth propeller device 10 described above, however, it is necessary,
               in order to maintain the direction of the ship, i.e., a course of the ship in a straight
               line, to frequently change the angle of the shaft 3 within a relatively small angle
               range so that the direction of the propeller member 5 may be varied to finely adjust
               the direction of the ship. Moreover, when making a turn, it is necessary to rotate
               the shaft 3 at a large angle to change the direction of the propeller member 5. In
               addition, when making an emergency stop, it is required to counterrotate the propeller
               member 5 to stop the ship.
 
            [0008] For these reasons, it is necessary to frequently actuate a large driving mechanism
               in order to rotate the azimuth propeller device 10 which is large and heavy. Accordingly,
               a further improvement in the conventional azimuth propeller device 10 has been awaited
               from the viewpoints of reducing energy consumption, improving durability, and decreasing
               manufacturing cost.
 
            SUMMARY OF THE INVENTION
[0009] The present invention takes into consideration the above-mentioned circumstances,
               and has as an object to provide an azimuth propeller device which is capable of maintaining
               the course of a ship without rotating the entire azimuth propeller device, and the
               steering force thereof is further improved when making a ship turn .
 
            [0010] In order to achieve the above object, the present invention provides an azimuth propeller
               device including: a current plate member; an azimuth pod fixed to a lower portion
               of the current plate member, the azimuth pod being provided with a propeller member;
               and an auxiliary steering member provided with the current plate member, wherein the
               current plate member and the azimuth pod are provided so as to be rotatable together
               along a vertical axis with respect to the bottom of a ship.
 
            [0011] In accordance with another aspect of the invention, the auxiliary steering member
               is a rear flap member rotatably attached to a trailing edge portion of the current
               plate member.
 
            [0012] In yet another aspect of the invention, the auxiliary steering member is a front
               flap member rotatably attached to a front edge portion of the current plate member.
 
            [0013] In yet another aspect of the invention, the auxiliary steering member is a front
               flap member rotatably attached to a front edge portion of the current plate member,
               and a rear flap member rotatably attached to a trailing edge portion of the current
               plate member.
 
            [0014] The present invention also provides an azimuth propeller device including: a current
               plate member; an azimuth pod fixed to the lower portion of the current plate member,
               the azimuth pod being provided with a propeller member; a vertical stabilizer disposed
               at a lower portion of the azimuth pod; and a trailing edge flap member rotatably attached
               to a rear edge portion of the vertical stabilizer, wherein the current plate member
               and the azimuth pod are provided so as to be rotatable together along a vertical axis
               with respect to the bottom of a ship.
 
            [0015] In accordance with yet another aspect of the invention, the auxiliary steering member
               is a pair of open-close flap members attached to a side wall portion of the current
               plate member, the pair of open-close flap members being disposed so as to open and
               close independently.
 
            [0016] In yet another aspect of the invention, the pair of open-close flap members are fully
               opened to make an emergency stop of a ship.
 
            [0017] In yet another aspect of the invention, the auxiliary steering member set forth above
               is combined with another auxiliary steering member described above.
 
            [0018] The present invention also provides the above azimuth propeller device further including:
               a pair of open-close members attached to a side wall portion of the vertical stabilizer,
               the pair of open-close flap members being disposed so as to open and close independently.
 
            [0019] According to the azimuth propeller device described above, since an auxiliary steering
               member is provided with the current plate member of the azimuth propeller device,
               it becomes possible to maintain the direction of a ship by the operation of the auxiliary
               steering member, without the necessity of operating the whole azimuth propeller device,
               and hence, the straightness of the travel of the ship can be secured.
 
            [0020] Also, since the steering force of the azimuth propeller device can be improved by
               operating the auxiliary steering member, a desired turning of the ship can be made
               by decreasing the steering angle of the azimuth propeller device as compared with
               the case where only the azimuth propeller device is used to make a ship turn.
 
            [0021] Accordingly, power required for the operation of the azimuth propeller device according
               to the present invention can be decreased as compared with a conventional azimuth
               propeller device, the entire body of which is operated to make, for instance, a ship
               turn. Therefore, remarkable effects, such as reduction in cost and improvement in
               durability, can be obtained according to the azimuth propeller device of the present
               invention.
 
            [0022] In yet another aspect of the present invention, the azimuth propeller device further
               includes at least one radiation member provided with an outer periphery of the azimuth
               pod, wherein the propeller member is a POD propeller member provided with the azimuth
               pod, and a motor which drives the POD propeller member is provided inside the azimuth
               pod.
 
            [0023] In accordance with another aspect of the present invention, the radiation member
               is a fin extending in the front and back direction of the azimuth pod.
 
            [0024] In yet another aspect of the present invention, the fin is twisted in the rotation
               direction of the POD propeller member from the front to back of the fin.
 
            [0025] According to the above azimuth propeller device, since at least one radiation member
               is provided with the outer periphery of the azimuth pod, it becomes possible to effectively
               release the heat, which is generated by the rotation of the motor inside the azimuth
               pod, into the surrounding water via the radiation member. That is, it becomes possible
               to effectively carry out a water-cooling operation using water of the ocean, a river,
               a lake, etc., in which the ship is traveling, and hence the air cooling operation
               can be eliminated or decreased to a minimum level. Accordingly, it has a remarkable
               effect on the reduction in the size and cost of the azimuth propeller device.
 
            [0026] Also, since at least one of the fins extending in the front and back direction of
               the azimuth pod is adopted as a radiation member, it becomes possible to secure a
               large heat transfer area to improve the radiation efficiency.
 
            [0027] Moreover, since the fin is twisted in the rotation direction of the POD propeller
               member from the front to back of the fin, water flow adjusting effect can be obtained
               in addition to the above-mentioned radiation effect. Accordingly, the present invention
               can also contribute to the improvement in the driving force.
 
            BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Some of the features and advantages of the invention have been described, and others
               will become apparent from the detailed description which follows and from the accompanying
               drawings, in which:
               
               
FIG. 1A is a schematic diagram showing a side view of an azimuth propeller device
                  according to the first embodiment of the present invention, and FIG. 1 B is a diagram
                  showing a cross-sectional view of the azimuth propeller device taken along the line
                  A-A shown in FIG. 1A;
               FIG. 2A is a schematic diagram showing a side view of an azimuth propeller device
                  according to the second embodiment of the present invention, and FIG. 2B is a diagram
                  showing a cross-sectional view of the azimuth propeller device taken along the line
                  B-B shown in FIG. 2A;
               FIG. 3A is a schematic diagram showing a side view of an azimuth propeller device
                  according to the third embodiment of the present invention, and FIG. 3B is a diagram
                  showing a cross-sectional view of the azimuth propeller device taken along the line
                  C-C shown in FIG. 3A;
               FIG. 4A is a schematic diagram showing a side view of an azimuth propeller device
                  according to the fourth embodiment of the present invention, and FIG. 4B is a diagram
                  showing a cross-sectional view of the azimuth propeller device taken along the line
                  D-D shown in FIG. 4A;
               FIG. 5A is a schematic diagram showing a side view of an azimuth propeller device
                  according to the fifth embodiment of the present invention, and FIG. 5B is a diagram
                  showing a bottom of the azimuth propeller device shown in FIG. 5A;
               FIG. 6A is a schematic diagram showing a side view of an azimuth propeller device
                  according to the sixth embodiment of the present invention, and FIG. 6B is a diagram
                  showing a cross-sectional view of the azimuth propeller device taken along the line
                  E-E shown in FIG. 6A;
               FIG. 7 is a schematic diagram showing a cross-sectional view of main parts of the
                  azimuth propeller device according to the seventh embodiment of the present invention;
               FIG. 8 is a schematic diagram showing a cross-sectional view of main parts of the
                  azimuth propeller device according to the eighth embodiment of the present invention;
               FIG. 9 is a schematic diagram showing a cross-sectional view of main parts of the
                  azimuth propeller device according to the ninth embodiment of the present invention;
               FIG. 10A is a schematic diagram showing a side view of an azimuth propeller device
                  according to the tenth embodiment of the present invention, and FIG. 10B is a diagram
                  showing a front elevational view of the azimuth propeller device shown in FIG. 10A;
               FIG. 11 A is a schematic diagram showing a side view of an azimuth propeller device
                  according to the eleventh embodiment of the present invention, and FIG. 11B is a diagram
                  showing a front elevational view of the azimuth propeller device shown in FIG. 11A;
               FIG. 12 is a schematic diagram showing an attachment of a conventional azimuth propeller
                  device at the stern portion of a ship; and
               FIG. 13A is a schematic diagram showing a side view of a conventional azimuth propeller
                  device, and FIG. 13B is a diagram showing a cross-sectional view of the azimuth propeller
                  taken along the line F-F shown in FIG. 13A.
 
            DETAILED DESCRIPTION OF THE INVENTION
[0029] The invention summarized above and defined by the enumerated claims may be better
               understood by referring to the following detailed description, which should be read
               with reference to the accompanying drawings. This detailed description of particular
               preferred embodiments, set out below to enable one to build and use particular implementations
               of the invention, is not intended to limit the enumerated claims, but to serve as
               particular examples thereof.
 
            [0030] The azimuth propeller device according to an embodiment of the present invention
               will be described with reference to FIGS. 1A and 1B. Note that in the following figures,
               elements which are the same as those described in the prior art are indicated by using
               the same numerals, and explanations thereof will be omitted.
 
            [0031] In the azimuth propeller device according to the first embodiment of the present
               embodiment shown in FIGS. 1A and 1B, the numeral 1 indicates a rear portion of the
               ship's bottom, 2 indicates an azimuth pod, 3 indicates a shaft, 4 indicates a current
               plate member, 5 indicates a propeller member, 6 indicates a rear flap member, and
               10A indicates an azimuth propeller device.
 
            [0032] As shown in the figures, the azimuth propeller device 10A is rotatably attached to
               the rear portion of the ship's bottom 1 via the shaft 3. In this specification, the
               term "the rear portion of the ship's bottom" means a portion of the bottom of a ship
               which is located at the back of a hull with respect to the travelling direction of
               the ship.
 
            [0033] The azimuth propeller device 10A includes the azimuth pod 2 accommodating a propeller
               drive mechanism (not shown in the figures) in the inside thereof, to which the propeller
               member 5 that exerts the driving force for the ship by delivering water backwards,
               is attached to the front or back thereof (back in the device 10A shown in FIG. 1A).
               The current plate member 4 having a streamlined cross sectional shape is integrally
               fixed to the upper portion of the azimuth pod 2. The current plate member 4 is attached
               to the lower portion of the shaft 3 which extends in the vertical direction, and the
               upper portion of the shaft 3 is coupled with a driving mechanism (not shown in the
               figures), which is disposed in the hull so that the shaft 3, the current plate member
               4, the azimuth pod 2, and the propeller member 5 can be integrally rotated. Note that
               a motor used for outputting the driving force for the propeller member 5 may be disposed
               in the azimuth pod 2 or in the hull of the ship.
 
            [0034] In the azimuth propeller device 10A, the rear flap member 6 is attached to a trailing
               edge portion 4a of the current plate member 4 as an auxiliary steering member. The
               rear flap member 6 is a thin plate member extending in the vertical direction. As
               shown in FIG. 1B, the front end portion of the rear flap member 6 is rotatably supported
               along a rotation axis 7 in the vertical direction with respect to the current plate
               member 4 so that the rear end portion 6a of the rear flap member 6 can be pivoted
               around the rotation axis 7 in the horizontal direction. A part or the whole of the
               driving mechanism (not shown in the figure) for pivoting the rear flap member 6 may
               be accommodated in the current flow plate member 4, and its operation is controlled
               to be linked with that of the azimuth propeller device 10A. That is, the timing, the
               direction, and the angle for pivoting the rear flap member 6 are controlled to be
               interlocked with the rotation angle or the driving force of the azimuth propeller
               device 10A.
 
            [0035] The azimuth propeller device 10A having the above-mentioned structure is capable
               of driving a ship using the driving force generated by the rotation of the propeller
               member 5, and obtaining steering function by rotating the whole azimuth propeller
               device 10A with respect to the rear portion of the ship's bottom 1 to change the travelling
               course of the ship.
 
            [0036] Also, when the ship travels in a certain direction, it becomes possible, by using
               the azimuth propeller device 10A, to maintain the direction of the ship by appropriately
               pivoting the rear flap member 6. That is, the ship provided with the azimuth propeller
               device 10A can suitably travel in a straight line by the operation of only the rear
               flap member 6, which is significantly smaller in size and weight compared with the
               azimuth propeller device 10A, without the necessity of rotating the entire azimuth
               propeller device 10A within a small angle range by using a huge driving mechanism.
 
            [0037] Also, when the ship makes a turn, if the rear flap member 6 is rotated in accordance
               with the rotation direction of the ship, in addition to the rotation of the azimuth
               propeller device 10A, the steering force for the ship can be further improved as compared
               with the case where only the azimuth propeller device 10A is employed. That is, according
               to the embodiment of the present invention provided with the rear flap member 6, a
               desired turn of the ship can be made by using substantially the same steering force
               although the steering angle of the azimuth propeller device 10A required is made smaller
               as compared with the case where only the azimuth propeller device 10A is used. Moreover,
               when making a turn of relatively small turning angle (i.e., a large turning radius),
               only the rear flap member 6 may need to be operated, and it is not necessary to rotate
               the azimuth propeller device 10A at all, to obtain a required steering force.
 
            [0038] Note that when the ship makes a turn, the rear flap member 6 is rotated in the same
               direction as the azimuth propeller device 10A. That is, when the ship makes a right
               turn with respect to its traveling direction, the trailing edge portion 4a of the
               azimuth propeller device 10A is rotated in the right hand side direction and the rear
               end portion 6a of the rear flap member 6 is also rotated in the right hand side direction
               with respect to the traveling direction of the ship.
 
            [0039] Next, a second embodiment according to the present invention will be described with
               reference to FIGS. 2A and 2B. In FIGS. 2A and 2B, the numeral 1 indicates a rear portion
               of the ship's bottom, 2 indicates an azimuth pod, 3 indicates a shaft, 4 indicates
               a current plate member, 5 indicates a propeller member, 8 indicates a front flap member,
               and 10B indicates an azimuth propeller device, and elements which are the same as
               those described in the first embodiment are indicated by using the same numerals,
               and the explanations thereof will be omitted.
 
            [0040] In the azimuth propeller device 10B according to the second embodiment of the present
               embodiment shown in FIGS. 2A and 2B, the front flap member 8 is attached to a front
               edge portion 4b of the current plate member 4 as an auxiliary steering member. The
               front flap member 8 is a thin plate member extending in the vertical direction, and
               is attached to the current plate member 4 so as to be protruding forward from the
               front edge portion 4b. As shown in FIGS. 2A and 2B, the rear end portion of the front
               flap member 8 is rotatably supported along a rotation axis 9 in the vertical direction
               with respect to the current plate member 4 so that the front end portion 8a of the
               front flap member 8 can be pivoted around the rotation axis 9 in the horizontal direction.
               A part or the whole of the driving mechanism (not shown in the figure) for pivoting
               the front flap member 8 may be accommodated in the current flow plate member 4, and
               its operation is controlled to be linked with that of the azimuth propeller device
               10B. That is, the timing, the direction, and the angle for pivoting the front flap
               member 8 are controlled to be interlocked with the rotation angle or the driving force
               of the azimuth propeller device 10B.
 
            [0041] The azimuth propeller device 10B having the above-mentioned structure is capable
               of driving a ship using the driving force generated by rotating the propeller member
               5, and obtaining steering function by rotating the whole azimuth propeller device
               10B with respect to the rear portion of the ship's bottom 1 to change the course of
               travel of the ship. Note that the adoption of the front flap member 8 has an advantage
               that the effect of the water flow generated by the rotation of the propeller member
               5 is likely to be smaller as compared with the case where the rear flap member 6 is
               adopted.
 
            [0042] Also, when the ship travels in a certain direction, it becomes possible to maintain
               the direction of the ship by appropriately pivoting the front flap member 8. That
               is, the ship provided with the azimuth propeller device 10B can suitably travel in
               a straight line by the operation of only the front flap member 8, which is significantly
               smaller in size and weight compared with the azimuth propeller device 10B, without
               the necessity of rotating the entire azimuth propeller device 10B within a small angle
               range by using a huge driving mechanism.
 
            [0043] Moreover, when the ship makes a turn, if the front flap member 8 is rotated in accordance
               with the rotation direction of the ship, in addition to the rotation of the azimuth
               propeller device 10B, the steering force for the ship can be further improved as compared
               with the case where only the azimuth propeller device 10B is employed. That is, according
               to this embodiment of the present invention provided with the front flap member 8,
               a desired turning of the ship can be made by using substantially the same steering
               force although the steering angle of the azimuth propeller device 10B required is
               made smaller as compared with the case where only the azimuth propeller device 10B
               is employed. Further, when making a turn of relatively small turning angle (i.e.,
               a large turning radius), only the front flap member 8 may need to be operated, and
               it is not necessary to rotate the azimuth propeller device 10B at all to obtain a
               required steering force.
 
            [0044] Note that when the ship makes a turn, the front flap member 8 is rotated in the same
               direction as the azimuth propeller device 10B. That is, when the ship makes a right
               turn with respect to its traveling direction, the trailing edge portion of the azimuth
               propeller device 10B is rotated in the right hand side direction and the front end
               portion 8a of the front flap member 8 is also rotated in the right hand side direction
               with respect to the traveling direction of the ship.
 
            [0045] Next, a third embodiment according to the present invention will be described with
               reference to FIGS. 3A and 3B. In FIGS. 3A and 3B, the numeral 1 indicates a rear portion
               of the ship's bottom, 2 indicates an azimuth pod, 3 indicates a shaft, 4 indicates
               a current plate member, 5 indicates a propeller member, 6 indicates a rear flap member,
               8 indicates a front flap member, and 10C indicates an azimuth propeller device, and
               elements which are the same as those described in the first and second embodiments
               are indicated by using the same numerals, and the explanation thereof will be omitted.
 
            [0046] In the azimuth propeller device 10C according to the third embodiment of the present
               embodiment shown in FIGS. 3A and 3B, the rear flap member 6 and the front flap member
               8 are attached to a trailing edge portion 4a and a front edge portion 4b, respectively,
               of the current plate member 4 as auxiliary steering members. That is, the rear flap
               member 6 described in the first embodiment, and the front flap member 8 described
               in the second embodiment are combined in this third embodiment according to the present
               invention. The operations of the rear flap member 6 and the front flap member 8 are
               controlled to be linked with the azimuth propeller device 10C. That is, the timing,
               the direction, and the angle for pivoting the rear flap member 6 and the front flap
               member 8 are controlled to be interlocked with the rotation angle or the driving force
               of the azimuth propeller device 10C.
 
            [0047] The azimuth propeller device 10C having the above-mentioned structure is capable
               of driving a ship using the driving force generated by rotating the propeller member
               5, and obtaining steering function by rotating the whole azimuth propeller device
               10C with respect to the rear portion of the ship's bottom 1 to change the course of
               travel of the ship.
 
            [0048] Also, when the ship travels in a certain direction, it becomes possible to maintain
               the direction of the ship by appropriately pivoting the rear flap member 6 and the
               front flap member 8. That is, the ship provided with the azimuth propeller device
               10C can suitably travel in a straight line by the operation of only the rear flap
               member 6 and the front flap member 8, each of which is significantly smaller in size
               and weight compared with the azimuth propeller device 10C, without the necessity of
               rotating the entire azimuth propeller device 10C within a small angle range by using
               a huge driving mechanism.
 
            [0049] Moreover, when the ship makes a turn, if the rear flap member 6 and the front flap
               member 8 are rotated in accordance with the rotation direction of the ship, in addition
               to the rotation of the azimuth propeller device 10C, the steering force for the ship
               can be further improved as compared with the case where only the azimuth propeller
               device 10C is employed. That is, according to this embodiment of the present invention
               provided with the rear flap member 6 and the front flap member 8, a desired turn of
               the ship can be made by using substantially the same steering force although the steering
               angle of the azimuth propeller device 10C required is made smaller as compared with
               the case where only the azimuth propeller device 10C is used. Further, when making
               a turn of relatively small turning angle (i.e., a large turning radius), only the
               rear flap member 6 and the front flap member 8 may need to be operated, and it is
               not necessary to rotate the azimuth propeller device 10C at all to obtain a required
               steering force.
 
            [0050] Note that when the ship makes a turn, the rear flap member 6 and the front flap member
               8 are rotated in the same direction as the azimuth propeller device 10C. That is,
               when the ship makes a right turn with respect to its traveling direction, the trailing
               edge portion 4a of the azimuth propeller device 10C is rotated in the right hand side
               direction, and the rear end portion 6a of the rear flap member 6 and the front end
               portion 8a of the front flap member 8 are also rotated in the right hand side direction
               with respect to the traveling direction of the ship.
 
            [0051] Also note that in the above mentioned third embodiment according to the present invention,
               the rear flap member 6 and the front flap member 8 may also be effectively used for
               stopping the ship in an emergency. That is, if the rear flap member 6 and the front
               flap member 8 are rotated 90 degrees in the right hand side and left hand side direction,
               respectively, with respect to the travelling direction of the ship, thereby forming
               a plate-shaped resistance member orthogonal to the traveling direction of the ship,
               the traveling distance required for the ship to make an emergency stop can be shortened.
 
            [0052] Next, a fourth embodiment according to the present invention will be described with
               reference to FIGS. 4A and 4B. In FIGS. 4A and 4B, the numeral 1 indicates a rear portion
               of the ship's bottom, 2 indicates an azimuth pod, 3 indicates a shaft, 4 indicates
               a current plate member, 5 indicates a propeller member, 10D indicates an azimuth propeller
               device, and 11R and 11L indicate (right and left) open-close flap members. Elements
               which are the same as those described in the first through third embodiments are indicated
               by using the same numerals, and the explanations thereof will be omitted.
 
            [0053] In the azimuth propeller device 10D according to the fourth embodiment of the present
               embodiment shown in FIGS. 4A and 4B, the open-close flap members 11L and 11R, respectively,
               are attached to side wall portions of the current plate member 4 as auxiliary steering
               members. The operations of the open-close flap members 11L and 11 R are controlled
               to be linked with the azimuth propeller device 10D. That is, the timing, the direction,
               and the angle for pivoting the pair of open-close flap members 11L and 11R are controlled
               to be interlocked with the rotation angle or the driving force of the azimuth propeller
               device 10D. Note that the numeral 11 a in FIGS. 4A and 4B indicates a shaft for supporting
               the rotation of the open-close flap members 11L and 11R.
 
            [0054] The azimuth propeller device 10D having the above-mentioned structure is capable
               of driving a ship using the driving force generated by rotating the propeller member
               5, and obtaining steering function by rotating the whole azimuth propeller device
               10D with respect to the rear portion of the ship's bottom 1 to change the travelling
               course of the ship.
 
            [0055] Also, when the ship travels in a certain direction, it becomes possible to maintain
               the direction of the ship by appropriately pivoting the open-close flap members 11L
               and 11R. That is, the ship provided with the azimuth propeller device 10D can suitably
               travel in a straight line by the operation of only the open-close flap members 11L
               and 11R, each of which is significantly small in size and weight as compared with
               those of the azimuth propeller device 10D, without the necessity of rotating the entire
               azimuth propeller device 10D within a small angle range by using a huge driving mechanism.
 
            [0056] Moreover, when the ship makes a turn, if the open-close flap members 11L and 11R
               are rotated in accordance with the rotation direction of the ship, in addition to
               the rotation of the azimuth propeller device 10D, the steering force for the ship
               can be further improved as compared with the case where only the azimuth propeller
               device 10D is employed. That is, according to this embodiment of the present invention
               provided with the open-close flap members 11L and 11R, a desired turning of the ship
               can be made by using substantially the same steering force although the steering angle
               of the azimuth propeller device 10D required is made smaller as compared with the
               case where only the azimuth propeller device 10D is used. Further, when making a turn
               of relatively small turning angle (i.e., a large turning radius), only the open-close
               flap members 11L and 11R may need to be operated, and it is not necessary to rotate
               the azimuth propeller device 10D at all, to obtain a required steering force.
 
            [0057] Next, the opening and closing operations of the open-close flap members 11L and 11R,
               when the ship makes a turn, will be described in detail. First, one of the open-close
               flap members 11L and 11R which is located at the outer side relative to the turning
               azimuth propeller device 10D, i.e., the open-close flap member disposed at the side
               wall of the current plate member 4 farther to the rotation center of the turn, is
               opened, and the other one of the open-close flap members is kept closed. Accordingly,
               when the ship makes a right turn with respect to the traveling direction of the ship,
               the open-close flap member 11L, which is attached to the left hand side wall portion
               of the current plate member 4 in the azimuth propeller device 10D, is opened and the
               open-close flap member 11R disposed at the right hand side wall portion is closed.
 
            [0058] Note that in the above mentioned fourth embodiment according to the present invention,
               the open-close flap members 11L and 11R may also be effectively used for stopping
               the ship in an emergency. That is, if the open-close flap members 11L and 11R are
               rotated 90 degrees in the right hand side and left hand side direction, respectively,
               with respect to the travelling direction of the ship, thereby forming a plate-shaped
               resistance member orthogonal to the traveling direction of the ship, the traveling
               distance required for the ship to make an emergency stop can be shortened.
 
            [0059] In addition, the structure used for providing the open-close flap members 11L and
               11R on the respective side wall portion of the current plate member 4 has an advantage,
               as compared with the structure used for providing the above mentioned rear flap member
               6 or the front flap member 8 with the trailing edge portion 4a and the front edge
               portion 4b, respectively, of the current plate member 4, in that it becomes easy to
               design the structure since a large installation area can be secured for the flap members
               11L and 11R.
 
            [0060] Next, a fifth embodiment according to the present invention will be described with
               reference to FIGS. 5A and 5B. In FIGS. 5A and 5B, the numeral 2 indicates an azimuth
               pod, 4 indicates a current plate member, 5 indicates a propeller member, 10E indicates
               an azimuth propeller device, 12 indicates a vertical stabilizer (fin), and 13 indicates
               a trailing edge flap member. Elements which are the same as those described in the
               first through fourth embodiments are indicated by using the same numerals, and the
               explanations thereof will be omitted. Note that in FIG. 5, the upper portion of the
               azimuth propeller device 10E, i.e., a rear portion of the ship's bottom 1 and a shaft
               3, are not shown.
 
            [0061] In the azimuth propeller device 10E according to the fifth embodiment of the present
               embodiment shown in FIGS. 5A and 5B, the vertical stabilizer 12 is disposed at the
               bottom portion of the azimuth pod 2 as a current plate member, and the trailing edge
               flap member 13 is attached to a rear edge portion 12a of the vertical stabilizer 12
               as an auxiliary steering member. That is, the vertical stabilizer 12 which exerts
               the same function as the current plate member 4 is disposed at the lower portion of
               the azimuth pod 2, and the trailing edge flap member 13 is attached to the vertical
               stabilizer 12.
 
            [0062] The trailing edge flap member 13, similar to the rear end flap member 6 attached
               to the current plate member 4 explained in the first embodiment, is a thin plate member
               extending in the vertical direction. The front end portion of the trailing edge flap
               member 13 is rotatably supported along a rotation axis (not shown in the figures)
               extending in the vertical direction with respect to the vertical stabilizer 12 so
               that a rear end portion 13a of the trailing edge flap member 13 may be pivoted around
               the rotation axis 9 in the horizontal direction. A part or the whole of the driving
               mechanism (not shown in the figures) for pivoting the trailing edge flap member 13
               may be accommodated in the vertical stabilizer 12, and its operation is controlled
               to be linked with that of the azimuth propeller device 10E. That is, the timing, the
               direction, and the angle for pivoting the trailing edge flap member 13 are controlled
               to be interlocked with the rotation angle or the driving force of the azimuth propeller
               device 10E.
 
            [0063] The azimuth propeller device 10E having the above-mentioned structure is capable
               of driving a ship using the driving force generated by rotating the propeller member
               5, and obtaining steering function by rotating the whole azimuth propeller device
               10E including the vertical stabilizer 12 with respect to the rear portion of the ship's
               bottom 1 to change the course of travel of the ship.
 
            [0064] Also, when the ship travels in a certain direction, it becomes possible to maintain
               the direction of the ship by appropriately pivoting the trailing edge flap member
               13. That is, the ship provided with the azimuth propeller device 10E can suitably
               travel in a straight line by the operation of only the trailing edge flap member 13,
               which is significantly smaller in size and weight compared with the azimuth propeller
               device 10E, without the necessity of rotating the entire azimuth propeller device
               10E within a small angle range by using a huge driving mechanism.
 
            [0065] Moreover, when the ship makes a turn, if the trailing edge flap member 13 is rotated
               in accordance with the rotation direction of the ship, in addition to the rotation
               of the azimuth propeller device 10E, the steering force for the ship can be further
               improved as compared with the case where only the azimuth propeller device 10E is
               employed. That is, according to this embodiment of the present invention provided
               with the trailing edge flap member 13, a desired turning of the ship can be made by
               using substantially the same steering force although the steering angle of the azimuth
               propeller device 10E required is made smaller as compared with the case where only
               the azimuth propeller device 10E is employed. Further, when making a turn of relatively
               small turning angle (i.e., a large turning radius), only the trailing edge flap member
               13 may need to be operated, and it is not necessary to rotate the azimuth propeller
               device 10E at all, to obtain a required steering force.
 
            [0066] Note that when the ship makes a turn, the trailing edge flap member 13 is rotated
               in the same direction as the azimuth propeller device 10E. That is, when the ship
               makes a right turn with respect to its traveling direction, the trailing edge portion
               4a of the azimuth propeller device 10E is rotated in the right hand side direction
               and the rear end portion 13a of the trailing edge flap member 13 is also rotated in
               the right hand side direction with respect to the traveling direction of the ship.
 
            [0067] The vertical stabilizer 12 fixed to the bottom of the azimuth pod 2 including the
               trailing edge flap member 13 has an advantage in that the disturbance in the water
               flow in the vicinity of the bottom of the ship can be minimized even if the steering
               operation is carried out by using the trailing edge flap member 13 since the distance
               between the bottom of the ship and the vertical stabilizer 12 is relatively large.
 
            [0068] Also, it becomes easy to design the structure for providing the trailing edge flap
               member 13 with the vertical stabilizer 12, since space can be easily secured on and
               in the vertical stabilizer 12.
 
            [0069] Next, a sixth embodiment according to the present invention will be described with
               reference to FIGS. 6A and 6B. In FIGS. 6A and 6B, the numeral 1 indicates a rear portion
               of the ship's bottom, 2 indicates an azimuth pod, 3 indicates a shaft, 4 indicates
               a current plate member, 5 indicates a propeller member, 6 indicates a rear flap member,
               10F indicates an azimuth propeller device, and 11R and 11L indicate (right and left)
               open-close flap members. Elements which are the same as those described in the first
               through fourth embodiments are indicated using the same numerals, and the explanations
               thereof will be omitted.
 
            [0070] The azimuth propeller device 10F according to the sixth embodiment is formed by combining
               the first and fourth embodiments according to the present invention described above,
               and the rear flap member 6 and the open-close flap members 11L and 11R are provided
               as auxiliary steering members. As mentioned above, the operation of the rear flap
               member 6 and the open-close flap members are controlled to be linked with the azimuth
               propeller device 10F.
 
            [0071] The azimuth propeller device 10F having the above-mentioned structure is capable
               of driving a ship using the driving force generated by rotating the propeller member
               5, and obtaining steering function by rotating the whole azimuth propeller device
               10F with respect to the rear portion of the ship's bottom 1 to change the course of
               travel of the ship.
 
            [0072] Also, when the ship travels in a certain direction, it becomes possible to maintain
               the direction of the ship by appropriately pivoting the rear flap member 6 and the
               open-close flap members 11L and 11R, and a ship provided with the azimuth propeller
               device 10F can suitably travel in a straight line.
 
            [0073] Moreover, when the ship makes a turn, if the rear flap member 6 and the open-close
               flap members 11L and 11R are rotated in accordance with the rotation direction of
               the ship, in addition to the rotation of the azimuth propeller device 10F, the steering
               force for the ship can be further improved as compared with the case where only the
               azimuth propeller device 10F is employed. That is, according to this embodiment of
               the present invention provided with the open-close flap members 11L and 11R, a desired
               turning of the ship can be made by using substantially the same steering force although
               the steering angle of the azimuth propeller device 10F required is made smaller as
               compared with the case where only the azimuth propeller device 10F is used. Further,
               when making a turn of relatively small turning angle (i.e., a large turning radius),
               only the rear flap member 6 and the open-close flap members 11 L and 11R may need
               to be operated, and it is not necessary to rotate the azimuth propeller device 10F
               at all, to obtain a required steering force.
 
            [0074] The operations of the rear flap member 6 and the open-close flap members 11L and
               11R, when the ship makes a turn, are the same as those described in the first and
               the fourth embodiment described above, and a further improvement in the straightness
               of the travel and steering of the ship can be expected by combining the operations
               of the rear flap member 6 and the open-close flap members 11L and 11R.
 
            [0075] Also, when making an emergency stop of the ship, the open-close flap members 11L
               and 11 R may be rotated 90 degrees in the right hand side and left hand side direction,
               respectively, with respect to the travelling direction of the ship, thereby forming
               a plate-shaped resistance member orthogonal to the traveling direction of the ship
               in order to shorten the traveling distance required for the ship to make an emergency
               stop.
 
            [0076] Next, a seventh embodiment according to the present invention will be described with
               reference to FIG. 7. The azimuth propeller device 10G according to the seventh embodiment
               is formed by combining the second and fourth embodiments of the present invention
               described above. That is, in the azimuth propeller device 10G, a structure is adopted
               in which the front flap member 8 shown in FIGS. 2A and 2B and the open-close flap
               members 11R and 11L shown in FIGS. 4A and 4B are combined so that a further improvement
               in the straightness of the travel and steering of the ship can be expected by combining
               the operations of the two members 8 and 11L and 11R.
 
            [0077] Also, when making an emergency stop of the ship, the open-close flap members 11L
               and 11R may be rotated 90 degrees in the right hand side and left hand side direction,
               respectively, with respect to the direction of travel of the ship, thereby forming
               a plate-shaped resistance member orthogonal to the direction of the travel of the
               ship in order to shorten the traveling distance required for the ship to make an emergency
               stop.
 
            [0078] Next, an eighth embodiment according to the present invention will be described with
               reference to FIG. 8. The azimuth propeller device 10H according to the eighth embodiment
               is formed by combining the third and fourth embodiments of the present invention described
               above. That is, in the azimuth propeller device 10H, a structure is adopted in which
               the rear flap member 6 shown in FIGS. 1A and 1B, the front flap member 8 shown in
               FIGS. 2A and 2B, and the open-close flap members 11R and 11L shown in FIGS. 4A and
               4B are combined so that a further improvement in the straightness in the travel and
               steering of the ship can be expected by combining the operations of the members 6
               and 8 and 11L and 11R.
 
            [0079] Also, when making an emergency stop of the ship, the open-close flap members 11L
               and 11R may be rotated at 90 degrees in the right hand side and left hand side direction,
               respectively, with respect to the travelling direction of the ship, and the rear flap
               member 6 and the front flap member 8 may be operated in the opposite directions, thereby
               forming two plate-shaped resistance members orthogonal to the traveling direction
               of the ship in order to shorten the traveling distance required for the ship to make
               an emergency stop.
 
            [0080] Next, a ninth embodiment according to the present invention will be described with
               reference to FIG. 9. The azimuth propeller device 10I according to the ninth embodiment
               is formed by combining the fourth and fifth embodiments of the present invention described
               above. That is, in the azimuth propeller device 10I, a structure is adopted in which
               the vertical stabilizer 12 and the trailing edge flap member 13 shown in FIGS. 5A
               and 5B and the open-close flap members 11R and 11L shown in FIGS. 4A and 4B are combined
               so that a further improvement in the straightness in the travel and steering of the
               ship can be expected by combining the operations of the members 12 and 13 and 11L
               and 11R.
 
            [0081] Also, when making an emergency stop of the ship, the open-close flap members 11L
               and 11R may be rotated 90 degrees in the right hand side and left hand side direction,
               respectively, with respect to the travelling direction of the ship, thereby forming
               a plate-shaped resistance member orthogonal to the traveling direction of the ship
               in order to shorten the traveling distance required for the ship to make an emergency
               stop.
 
            [0082] As explained above, according to the azimuth propeller device of the present invention,
               since the auxiliary steering member(s) is provided, it becomes possible to obtain
               excellent straightness in the travel of the ship without the necessity of operating
               the entire azimuth propeller device, and to improve the steering function of the ship.
 
            [0083] Also, by using the open-close flap members 11L and 11R and/or the rear flap member
               6 and the front flap member 8, it becomes possible to shorten the traveling distance
               required for the ship to make an emergency stop.
 
            [0084] Next, a tenth embodiment according to the present invention will be described with
               reference to FIGS. 10A and 10B. The azimuth propeller device 10J according to the
               tenth embodiment is formed by combining the first embodiment of the present invention
               described above with a (plurality of) radiation fins 14 (i.e., a radiation member).
 
            [0085] The azimuth propeller device 10J includes the azimuth pod 2 accommodating a motor
               for driving the POD propeller (not shown in the figures) in the inside thereof, to
               which the POD propeller member 5 that exerts the driving force for the ship by driving
               water backwards, is attached to the front or back thereof (back in the device 10A
               shown in FIG. 1A).
 
            [0086] As shown in FIGS. 10A and 10B, a number of radiation fins 14 are attached to the
               outer periphery of the azimuth pod 2 so as to extend therefrom. Each of the radiation
               fins 14 is a plate-like member extending in the front-to-back direction of the azimuth
               pod 2, i.e., the travelling direction by the driving force of the POD propeller member
               5. It is preferable to use a member having excellent thermal conductivity for the
               radiation fins 14.
 
            [0087] Note that although eighteen of the radiation fins 14 are radially attached to the
               outer periphery of the azimuth pod 2 with an equal interval between each other, the
               present invention is not limited to this particular configuration.
 
            [0088] In the azimuth propeller device 10J having the above-mentioned structure, heat generated
               from the motor (not shown in the figures) for rotating the POD propeller member 5
               is transmitted to each of the radiation fins 14 via the wall of the azimuth pod 2,
               and is released into the surrounding water from the surface of each radiation fin
               14. That is, the azimuth pod 2 is cooled by means of a water-cooling system via the
               radiation fins 14 according to the tenth embodiment of the present invention. For
               this reason, components required in an air-cooling system of a conventional art, such
               as a power source for the air-cooling system, a driving source for actuating an impelling
               means, such as a fan, and a passage for the cooling air, become unnecessary, and hence,
               not only can the space, energy consumption, and cost be reduced, but also the durability
               and the reliability of the azimuth propeller device can be improved according to the
               tenth embodiment of the present invention.
 
            [0089] Also, if the entire heating value cannot be covered by the water-cooling system of
               the embodiment of the present invention, such as for the case where the heating value
               of the motor is large, it is possible to use the water-cooling system of the present
               invention together with the conventional air-cooling system. In such a case, since
               the burden for the air-cooling system can be eased as compared with that in the conventional
               system, the size of the fan or of the passage for the cooling air can be decreased.
 
            [0090] Next, the eleventh embodiment according to the present invention will be described
               with reference to FIGS. 11A and 11B. Note that elements which are the same as those
               described in the embodiment shown in FIGS. 1A through 10B are indicated by using the
               same numerals, and the explanations thereof will be omitted.
 
            [0091] In this embodiment, the azimuth propeller device 10K according to the eleventh embodiment
               is formed by combining the first embodiment of the present invention described above
               with a current plate fin 15 which is adopted as a radiation member. The current plate
               fin 15 is formed by, in general, twisting the above-mentioned fin 14 in the rotation
               direction of the POD propeller 5 from the front to the back thereof. In the example
               shown in FIGS. 11A and 11B, the POD propeller 5 rotates in a clockwise direction viewed
               from the front (in the traveling direction) of the azimuth propeller device 10K as
               indicated by the arrow 13 in FIG. 11B, and each of the current plate fins 15 is angled
               or inclined from the front toward the back. The inclination is due to the twist of
               the current plate fin 15 so as to upturn the tail portion of the current plate fin
               15 in the rotation direction of the POD propeller 5 with respect to the axis of the
               azimuth pod 2. That is, an inclination surface 15a of the current plate fin 15 is
               formed along the flow of water which is drawn by the POD propeller 5.
 
            [0092] If the current plate fins 15 having the above-mentioned structure are adopted, it
               becomes possible to obtain water flow adjusting function for the water drawn by the
               POD propeller 5 in addition to the above-mentioned water-cooling function. Accordingly,
               it becomes possible to decrease the loss, and hence, the driving force exerted by
               the rotating the POD propeller 5 can be increased.
 
            [0093] Note that the structures of the azimuth propeller device according to the embodiments
               of the present invention are not limited to those described above, and can be modified
               within the scope of the present invention. For instance, the structure according to
               any one of the second to ninth embodiments of the present invention can suitably be
               combined with the radiation member described in the tenth or eleventh embodiment of
               the present invention. Also, a member having an excellent thermal conductive property
               may be intervened between the azimuth pod and the motor so as to further enhance the
               thermal conduction from the motor.
 
            [0094] Having thus described example embodiments of the invention, it will be apparent that
               various alterations, modifications, and improvements will readily occur to those skilled
               in the art. For instance, a front flap member may be provided also with the vertical
               stabilizer 12. Such alterations, modifications, and improvements, though not expressly
               described above, are nonetheless intended and implied to be within the spirit and
               scope of the invention. Accordingly, the foregoing discussion is intended to be illustrative
               only; the invention is limited and defined only by the following claims and equivalents
               thereto.