Impeller for fan, fan using the same, and air conditioner using the same

Description

Technical Field of the Invention

[0001] The present invention relates to an impeller used in a fan, a fan using the impeller, and an air conditioner using the same. An impeller as specified in the preamble of Claim 1 is known from US-A-1 807 397.

Background of the Invention

[0002] A plan of an impeller of a conventional mixed flow fan is shown in Fig. 15, and a rotation locus diagram of the impeller is given in Fig. 15. In the impeller used in such mixed flow fan, the gas flows in the impeller in inclination toward the rotary shaft. That is, in Fig. 15, the impeller 18 of the mixed flow fan comprises a truncated conical hub 20, and a plurality of blades 19 disposed in the hub 20. The rotation locus of the impeller 18 is shown in Fig. 14. The fan comprises this impeller 18, a casing accommodating the impeller 18, a rotary shaft coupled to the hub 20, and a motor. As the impeller 18 is rotated by the motor, a blowing action takes place. When the aspect ratio b/L, or the ratio of the chord length L of the blade at the representative square mean radius position of the vanes 19 and the representative actual length b in the radial direction of the blades is 1 or less, that is, in a range of b/L≤1, the number of blades 19 required for obtaining a sufficient static pressure is at least three or more. The front edge 21 of the blades 19 has a logarithmic spiral or similar curve.

[0003] In the conventional configuration, however, when the aspect ratio is 1 or less (that is, in a range of b/L≤1), in the fan of the impeller having at least three blades 19 or more, a blade end vortex 19D occurs in the arrow direction near the outer circumference of the rotating blades 19. The blade end vortex 19D was separated from the blade 19, and had a large effect on the influent air state of the succeeding blade 19. That is, the succeeding blade 19 had a large effect on the blade end vortex 19D generated and separated from the preceding vane, and the succeeding blade 19 worked pneumatically while receiving a largely disturbed influent air. Therefore, due to the effects of the blade end vortex 19D, there was a limit in reduction of noise and improvement of static pressure characteristic.

[0004] Further, as the number of blades 19 increases, the volume occupied by the impeller increases, and the manufacturing cost of the impeller is raised.

[0005] It is hence an object of the invention to reduce the noise of the impeller for fan, enhance the static pressure, and lower the manufacturing cost of the impeller.

Summary of the Invention

[0006] The impeller for fan of the invention is defined in Claim 1.

[0007] Preferably, the two blades are disposed symmetrically to the center of the hub.

[0008] The fan of the invention comprises a motor, and an impeller connected to the motor as specified in Claim 9.

[0009] The air conditioner of the invention is specified in Claim 15.

[0010] In this constitution, since the pitch of the two blades is sufficiently wide, the blade end vortex of air generated on the negative pressure surface near the outer circumference of the rotating blade is separated from the blade and flows away, thereby reducing the effect given to the influent air state of the other blade rotating behind. As a result, the disturbance of the influent air flow on each blade is decreased. The influent air getting into each blade is smooth. Therefore, air separation, decline of speed, and other unstable phenomena in the succeeding blade in rotation are less likely to occur. Hence, the noise is lower and the static pressure is enhanced in the blades.

[0011] Further, the impeller having two blades is smaller in volume than the impeller having three or more blades, so that the manufacturing cost of the impeller is lowered.

Brief Description of the Drawings

[0012] 

Fig. 1 is a rotation locus diagram of impeller in a mixed flow fan using an impeller for fan in an example not covered by the present invention.

Fig. 2 is a plan of the impeller for fan in an example not covered by the present invention.

Fig. 3 is a development of a blade by cutting off the impeller for fan in an example not covered by the present invention at a representative square mean radius position, developing it, and applying a thick blade.

Fig. 4 is a development of a blade by cutting off the impeller for fan in an example not covered by the present invention at a representative square mean radius position, developing it, and applying a thin blade having a specific thickness.

Fig. 5 is a schematic diagram showing an operating status of the impeller for fan in an example not covered by the present invention.

Fig. 6 is a characteristic diagram showing the relation between the aspect ratio b/L of the impeller for fan in an example not covered by the present invention and the air flow volume at blowing noise 41 dB.

Fig. 7 is a characteristic diagram comparing the experimental values of static pressure characteristics, between an impeller having two vanes in the impeller for fan in an example not covered by the present invention, and an impeller having three blades of a conventional impeller for fan.

Fig. 8 is a rotation locus diagram of the impeller in the previous example not covered by the invention by employing the impeller for fan in a further example not covered by the invention in an axial flow fan.

Fig. 9 is a plan of the impeller using the impeller for fan in a further example not covered by the invention in an axial flow fan.

Fig. 10 is a sectional view in radial direction of the impeller in embodiment of the present invention by employing the impeller for fan in the embodiment of the invention in a mixed flow fan.

Fig. 11 is a diagram showing results of experiment of noise spectrum of impeller for fan in the embodiment of the present invention.

Fig. 12 is a plan showing the behavior of blade end vortex of impeller in a further example not covered by the present invention by employing the impeller for fan in a further example not covered by the invention in a mixed flow fan.

Fig. 13 is a schematic diagram of an air conditioner using the fan having the impeller of the previous examples or that of the embodiment of the invention.

Fig. 14 is a plan of a conventional impeller for fan.

Fig. 15 is a rotation locus diagram of the conventional impeller for fan.

Reference Numerals

[0013] 

1, 15, 16, 40

Impeller

2, 14

Blade

2a

Concave curve shape

2b

Convex curve shape

3, 13

Hub

4

Front edge

5

Rear edge

6

Tip

7

Thick blade

8, 8a, 8b

Negative pressure surface

9, 9a

Pressure surface

10

Thin blade

11

Casing

12

Motor

17

Triangular auxiliary blade

33D

Blade end vortex

50

Air conditioner

51

Indoor unit

52

Outdoor unit

53

Piping

54

Heat exchanger

55

Fan

56

Impeller

L

Chord length of blade at representative square mean radius position of blade

b

Representative actual length in radial direction of blade

b/L

Aspect ratio

Description

[0014] The impeller for fan according to the invention is defined in Claim 1.

[0015] Preferably, the individual blades are mutually disposed symmetrically to the center of the hub.

[0016] In this constitution, since the pitch of the blades is sufficiently wide, the blade end vortex of air generated on the negative pressure surface near the outer circumference of the rotating blade is separated from the blade and flows away, thereby reducing the effect given to the influent air state of the blade rotating behind. Thus, the two blades do not have effects of the blade end vortex mutually. As a result, the disturbance of the influent air flow on each blade is decreased, and a smooth influent air gets into each blade. Therefore, air separation, decline of speed, and other unstable phenomena in each blade are less likely to occur.

[0017] Further, the impeller having two blades has a smaller volume than the impeller having three blades or four blades.

[0018] In the radial section of each blade, the portion from around the representative square mean radius position of the blade to the position at the outer circumference has a concave curve shape to the windward side, and the portion from around the representative square mean radius position of the blade to the position at the hub side has a convex curve shape to the windward side.

[0019] In this constitution, since the blade has a concave curve shape, the blade itself becomes a stream-line body in the rotating direction of the blade. Therefore, in the case of two blades, the blade rotating noise or "nZ" sound becomes lower than the sound pressure level of the turbulent flow noise. As a result, generation of abnormal sound in the entire impeller is prevented. Further, actual auditory sense is improved.

[0020] Preferably, one point of triangular auxiliary blade is overlapped on the intersection of the front edge of the blade and the outer circumference, and one side of the triangular auxiliary blade is formed in tight contact with the front edge. Thus, the triangular auxiliary vane is disposed in the blade as the principal blade.

[0021] In this constitution, starting from the leading end of the triangular blade, the blade end vortex is generated conically on the negative pressure surface of the blade, and this blade end vortex is separated and flows away in the midst of the blade. The triangular vane has an action of defining the generation of blade end vortex at its leading end. Accordingly, the triangular blade defines the state of generation of the blade end vortex on the negative pressure surface near the outer circumference of the blade, and the state of the blade end vortex separating from the blade and flowing away. Therefore the triangular blade has an action of minimizing the effect of the blade end vortex on the blade rotating behind. Hence, even in the impeller having two blades sufficiently wide in the pitch between blades, the influent air state of the blade rotating behind can be kept in the smooth and optimum state having a further smaller turbulent flow. The succeeding blade is less influenced by the effect of the blade end vortex, and the influent air into the blade is most smooth, and separation, decline of speed and other unstable phenomena in the succeeding blades are less likely to occur.

[0022] Preferably, the fan having such impeller is installed in the outdoor unit of the air conditioner having a heat exchanger.

[0023] In this constitution, the outdoor unit operates quietly. Further, the manufacturing cost is low. The design is easier and it is more advantageous.

[0024] Exemples not covered by the present invention are described below while referring to Figs. 1 to Fig. 9 and Figs. 12 and 13. Embodiments of the invention are described with reference to Figs. 9 and 10 and those of prior art to Figs. 9 and 10 and those of prior art to Figs. 14 and 15.

Exemple (not covered by the invention)

[0025] Fig. 1 to Fig. 9 show the impeller for fan of an example not covered by the invention. Fig. 1 is a rotation locus diagram of impeller used in a mixed flow blower. Fig. 2 is a plan of the impeller for the mixed flow fan. Fig. 3 is a development by cutting off the impeller for the fan at a representative square mean radius position, and developing it. In Fig. 3, the blade is a thick blade. Fig. 4 is a development by cutting off the impeller for the fan at a representative square mean radius position, and developing it, in which a thin blade of a specific thickness is applied as the blade. Fig. 5 is a schematic diagram showing an operating status of the impeller used in the fan. Fig. 6 is a characteristic diagram of characteristic experiment showing the performance of the impeller for the fan, in which the axis of abscissas denotes the aspect ratio b/L, and the axis of ordinates represents the air flow volume at blowing noise 41 dB. Fig. 7 is a characteristic diagram comparing the static pressure characteristics between an impeller for fan having two blades in this example, and an impeller for fan having three blades in a prior art. Fig. 8 is a rotation locus diagram of the impeller for fan when used in an axial flow fan. Fig. 9 is a plan of the impeller for the axial flow fan.

[0026] In Fig. 1, the impeller 1 used in the mixed flow fan comprises a truncated conical hub 3, and two blades 2 disposed on the outer circumference of the hub 3. The two blades 2 mutually have an identical shape, and the blades 2 are installed at mutually facing positions. That is, the blades 2 are disposed at mutually symmetrical positions to the center of the hub 3. The blades 2 are defined by the aspect ratio b/L where L is the chord length of the blade at the representative square mean radius position of the blade and b is the representative actual length in the radial direction of the blade. The aspect ratio is equal to 1 or less. That is, the aspect ratio is specified in a range of b/L≤1. Thus, two blades 2 having the aspect ratio defined in this range are disposed.

[0027] The constitution is further described below.

[0028] The hub 3 is a trapezoidal body having a circular section. Supposing the minimum radius of the circular shape of the hub 3 to be r1, and the maximum radius thereof to be r2, the representative hub radius "r" is defined as r = (r1 + r2)/2.

[0029] Supposing the distance from the center of the hub to the largest leading end of the blade to be R2 and the distance from the center of the hub to the smallest leading end of the blade to be "R1", the representative radius "R" of the impeller is defined as R = (R1 + R2)/2.

[0030] The representative square mean radius "Rr" is defined as Rr = ((R² + r²)/2)^1/2. The length "L" defined above is the chord length of the blade at this position of representative square mean radius "Rr".

[0031] In Fig. 1, the central line of the impeller 1 is 31C-31C, and the apex of the cone passing the representative square mean radius "Rr" is "P1". The development by cutting off the blade 2 along the line 32A-32A of the cone is shown in Fig. 3 and Fig. 4. The chord length of the blade 2 is "L".

[0032] The line 32A-32A is seen in curve 32A-32A in the plan in Fig. 2. In Fig. 1, the representative actual length "b" in the radial direction of the blade 2 is the actual length in the span direction of the blade 2 linking the position of the representative hub radius "r" and the position of the representative radius "R".

[0033] As shown In Fig. 5, the shaft of the motor 12 is fixed to the hub 3, and they are accommodated in a proper casing 11. As the impeller 1 is rotated by the motor 12, a blowing action is generated as indicated by arrow. At this time, the majority of the air In Fig. 1 flows in from the front edge 4 of the blade 2, and flows out from the rear edge 5. Thus, the impeller 1 works pneumatically.

[0034] In Fig. 1, the ratio b/L of the chord length L at the representative square mean radius position of the impeller 1 for the mixed flow fan and the representative actual length "b" in the radial direction of the blade is the aspect ratio.

[0035] Fig. 6 is a characteristic diagram showing the relation between the aspect ratio b/L of the impeller having two blades, and the air flow rate at blowing noise 41 dB. Fig. 6 is based on the data of the experiment of the impeller 1 having a diameter (⌀) of 415 mm.

[0036] As clear from Fig. 6, when the aspect ratio is in a range of b/L≤1, the air flow rate at blowing noise 41 dB is saturated. However, at the aspect ratio in a range of b/L≥1, the air flow rate is decreased suddenly.

[0037] The impeller 1 for mixed flow fan of this exemple has two blades 2 disposed in the hub 3. The aspect ratio b/L of the chord length "L" of the blade 2 at the representative square mean radius position of the blade 2 and the representative actual length b in the radial direction of the blade 2 is set in a range of b/L≤1, and the impeller 1 has two blades having the specified aspect ratio. The chord length of the outer side of the blade is longer than the chord length of the hub side.

[0038] In this constitution, in the impeller with the vanes having an aspect ratio in a range of b/L≤1, since the pitch of the blades 2 is sufficiently wide, the blade end vortex 33D generated on the negative pressure surface 8 near the outer circumference of each blade 2 (that is, near the tip 6) is separated from the blade 2 and flows away, thereby reducing the effect given to the influent air state of the vane 2 rotating behind. Thus, the blades 2 do not have effects of the blade end vortex 33D mutually. As a result, the disturbance of the influent air flow on each blade 2 is decreased, and a smooth influent air gets into each blade 2. Therefore, separation, decline of speed, and other unstable phenomena in the blades 2 are less likely to occur. Hence, the air flow rate at same noise level of the impeller 1 is improved. The data supporting it is shown in Fig. 6. Fig. 6 is a characteristic diagram 6 of the impeller 1 for the mixed flow fan.

[0039] Since the effect of the blade end vortex 33D due to the preceding rotating blade on the succeeding blade 2 is small, unstable phenomena such as separation and decline of speed hardly occur in the succeeding blade 2. As a result, the static pressure characteristic of the impeller 1 is improved. Fig. 7 shows a characteristic curve of static pressure characteristic comparing two blades and three blades in the axial flow fan. In Fig. 7, the impeller for axial flow fan with diameter of 415 mm is operated at a rotating speed of 712 rpm, and the static pressure characteristic is shown at the opening air flow rate point of 29.5 m³/min. The opening air flow rate point is the air flow rate when the static pressure is 0. In the range from the opening air flow rate point to the air flow rate point Q1, the impeller having two blades shows a stronger static pressure than the impeller having three blades. In the range from the air flow rate point Q1 to the air flow rate point Q2, the impeller having two blades and the impeller having three blades show the same static pressure. In the range from the air flow rate point Q2 to the closing air flow rate point (where air flow rate is 0), the impeller having three blades shows a slightly stronger static pressure than the impeller having two blades. The fan used in the air conditioner is operated, in heating mode, usually in a range from the opening air flow rate point nearly to the air flow rate point Q2. Only in the heating operation when frosting on the heat exchanger is extremely promoted, it is operated in the range from the air flow rate point Q2 to the closing air flow rate point (air flow rate being 0), and defrosting operation does not take place so often. Therefore, the performance in the range from the air flow rate point Q2 to the closing air flow rate point in the fan used in the air conditioner is not so important for designing of the apparatus. Thus, in the range from the air flow rate point Q2 to the closing air flow rate point (air flow rate being 0), the performance of the impeller having three blades showing slightly stronger static pressure than the impeller having two blades is not important for the fan used in the air conditioner.

[0040] Further, the impeller having two blades is smaller in occupying volume than the impeller having three blades or four blades. Hence, the manufacturing cost of the impeller is lower.

[0041] In Fig. 1, the center line of the impeller is line 31C-31C, the apex of the line 32A-32A of the cone passing the representative square mean radius "Rr" is "P1", and the development of the blade cut off along the line 32A-32A of the cone is shown in Fig. 3 and Fig. 4. Fig. 3 shows the blade having a thick blade 7. In Fig. 3, the front edge 4 of the blade 7 in the sectional shape of the blade 7 is an arc, and the rear edge 5 has a pointed end. The blade 7 has a pressure surface 9 and a negative pressure surface 8. In Fig. 3, each blade has a circular front edge 4 and a sharp rear edge 5, and the shape from the rear edge to the front edge is gradually increased in thickness.

[0042] Fig. 4 shows the blade having a thin blade 10. In Fig. 4, the blade 10 has a thin section of a uniform thickness. That is, the shape from the rear edge to the front edge nearly has a same thickness. The blade 10 has a pressure surface 9a and a negative pressure surface 8a. The pressure surface 9a is positioned at the windward side, and the negative pressure surface 8b is positioned at the windward side.

[0043] As an impeller for fan in a further exemple not covered by the invention, an axial flow fan is explained. A rotation locus diagram of the impeller in the axial flow fan is shown in Fig. 8, and its plan is given in Fig. 9. In Fig. 8 and Fig. 9, an impeller 15 has two blades 14. Herein, the position at the representative square mean radius "Rr" is indicated by line 34B-34B. In this impeller 15 for axial flow fan, too, the aspect ratio b/L of the chord length "L" of the blade 14 at the representative square mean radius position of the blade 14 and the representative actual length b in the radial direction of the blade 14 is set in a range of b/L≤1. Two blades having the aspect ratio set in the specified range are installed in a hub 13.

[0044] The impeller for the axial flow fan having such constitution has the same action and effect as the impeller for the mixed flow fan.

Embodiment of the present invention

[0045] Fig. 10 is a sectional view in radial direction of the impeller for mixed flow blower in an exemplary embodiment of the invention. In Fig. 10, the radial sectional view along line 35B-35B in Fig. 2 is shown, but the vanes of the impeller of this exemplary embodiment are different from the blades of the impeller in previous exemple of Figures 1 to 9. Fig. 11 is a diagram showing results of experiment of noise spectrum of impeller for mixed flow fan in this exemplary embodiment of the invention.

[0046] The impeller of this exemplary embodiment is same as the impeller of the previous examples not covered by the invention, except that only the shape of the blades is different. The parts having the same fan and same action and effect as in the previous examples are identified with same reference numerals, and detailed description is omitted, and different points are mainly explained.

[0047] The shape from around the line 36A-36A passing the representative square mean radius "Rr" of the blade 2 to the position at the tip 6 side is a concave curve shape 2a toward the windward side, and the shape from around the line 36A-36A passing the representative square mean radius Rr to the position of the hub 3 side is a convex curve shape 2b toward the windward side. Two blades 2 having such shape are disposed in the hub 3. These two blades 2 are disposed symmetrically to the center of the hub 3. Each blade 2 has a negative pressure surface 8b and a pressure surface 9b. The impeller 16 has two blades 2 having such shape. The impeller 16 is used in the mixed flow fan.

[0048] In this constitution, since the shape from around the line 36A-36A passing the representative square mean radius "Rr" of the blade 2 to the position at the outer peripheral side is a concave curve shape toward the windward side, the blade 2 itself becomes a stream-line body in the rotating direction of the impeller 16. Therefore, in the case of two blades, the rotating noise of the blade 2 or "nZ" sound becomes lower than the sound pressure level of the turbulent flow noise. As a result, generation of abnormal sound in the entire impeller 16 is prevented, and further, actual auditory sense is improved. Such effects are understood from the noise spectrum in Fig. 11.

[0049] Fig. 11 shows the noise spectrum measured when the impeller for mixed flow fan shown in Fig. 10 is operating at a rotating speed of 720 rpm and the air flow rate is 29.8 m³/min. The impeller 16 including the blades 2 has a diameter of 415 mm. The blade has a circular front edge and a pointed rear edge.

[0050] The sound pressure level near 1 kHz is a turbulent flow noise. The 1nZ sound, and its higher harmonics of 2nZ, 3nZ and 4nZ sound are rotating noise. As compared with the sound pressure level of turbulent flow noise near 1 kHz, it is clearly known from Fig. 11 that the sound pressure level is lower in the rotating noise of the blade, that is, 1nZ sound, and its higher harmonics of 2nZ, 3nZ and 4nZ sound.

[0051] In this exemplary embodiment of the invention the impeller used in the mixed flow fan is explained, but the same effects are obtained in the impeller used in the axial flow fan.

Exemplary Embodiment 3

[0052] Fig. 12 is a plan of the impeller for mixed flow fan in a further example not covered by the present invention. The impeller of this further example is same as the impeller of the previous example according to Figures 1 to 9, except that only the shape of the blades is different. The parts having the same fan and same action and effect as in the said example of Figures 1 to 9 are identified with same reference numerals, and detailed description is omitted, and different points are mainly explained.

[0053] In Fig. 12, one point of a triangular auxiliary blade 17 is overlapped with the intersection of the front edge 4 and tip 6 of the blade 2 as the principal blade, and one side of the triangular auxiliary blade 17 is disposed in tight contact with the front edge 4 of the blade 2. Two blades 2 having such triangular auxiliary blade 17 are disposed in the hub 3. The blades 2 are disposed symmetrically to the center of the hub 3. Thus, an impeller 40 for mixed flow fan is composed.

[0054] In this constitution, starting from the leading end of the triangular auxiliary blade 17, the vane end vortex 33D is generated conically on the negative pressure surface of the blade 2, and this blade end vortex 33D is separated and flows away in the midst of the blade. The leading end of the triangular auxiliary blade 17 has an action of defining the generation of blade end vortex 33D. Accordingly, it defines the basic points of the state of generation of the blade end vortex 33D on the negative pressure surface near the tip 6 of the blade 2, and the state thereof separating from the blade 2 and flowing away. Therefore it minimizes the effect of the blade end vortex 33D on the vane 2 rotating behind. Hence, even in the case of vanes with the aspect ratio in a range of b/L≤1 and having two blades sufficiently wide in the pitch between vanes, the influent air state of the blade 2 rotating behind can be kept in the smooth and optimum state having a further smaller turbulent flow. Relatively, the succeeding blade 2 is less influenced by the effect of the blade end vortex 33D, and the influent air into the blade is most smooth, and separation of air, decline of speed and other unstable phenomena in the blades 2 are less likely to occur. As a result, the blade noise is further suppressed and the static pressure is further enhanced.

[0055] In this example, the impeller used in the mixed flow fan is explained, but the same effects are obtained in the impeller used in the axial flow fan.

[0056] An air conditioner is shown in Fig. 13. In Fig. 13, an air conditioner 50 comprises an indoor unit 51 installed indoors, an outdoor unit 52 installed outdoors, and a circulation piping 53 installed between the indoor unit 51 and outdoor unit 52. The indoor unit 51, outdoor unit 52, and circulation piping 53 compose a refrigeration cycle of refrigerant.

[0057] The outdoor unit 52 includes a heat exchanger 54 and a fan 55. The fan 55 has an impeller 56. As the impeller 56, the impeller 1, impeller 15 or impeller 40 explained in the examples of Figures 1 to 9, 12 and 13 or that of the invention of Figures 9 and 10 are used. The fan 55 has a blowing action for heat exchange of the heat exchanger 54.

[0058] That is, the fan 55 sends wind into the heat exchanger 54. The fan 55 has a function of moving the near around the heat exchanger 54 by force.

[0059] In the air conditioner 50, the noise generated from the fan 55 is extremely lower than in the air conditioner using the conventional fan. Further, the blowing performance and heat exchange performance are enhanced. Moreover, the manufacturing cost is lower.

[0060] Specifically, the two blades are mutually free from effects of blade end vortex of the other blade, and the influent air coming into each blade is less turbulent and more smooth, and separation at blade, decline of speed and other unstable phenomena are less likely to occur. As a result, the noise generated by the blade is extremely small. The static pressure is improved. The volume occupied by the impeller is decreased, and the manufacturing cost is saved.

[0061] Moreover, the blade rotating noise of "nZ" sound and its higher harmonics are lower than the sound pressure level of turbulent flow noise, and generation of abnormal noise is prevented in the entire impeller. Further, the actual sensory feel is satisfactory.

[0062] Further, if the blade has a triangular auxiliary blade, these effects are much more enhanced.

[0063] In the constitution of the air conditioner of the invention, the noise released from the outdoor unit is much lower than in the conventional air conditioner. The blowing performance and heat exchange performance of the air conditioner are improved. In addition, a more inexpensive air conditioner is obtained.

Claims

1. An impeller for fan comprising:

a hub (3), and two blades (2) disposed in said hub, wherein said hub is a trapezoidal body having a circular section, characterized in that supposing the minimum radius of the circular shape of said hub to be "r1", and the maximum radius thereof to be "r2", a representative hub radius "r" is defined as "r=(r1+r2)/2",

further supposing the distance from the centre of said hub to the largest leading end of said blade to be "R2" and the distance from the centre of said hub to the smallest leading end of said blade to be "R1", a representative radius "R" of the impeller being defined as "R=(R1+R2)/2",

a representative square mean radius "Rr" is defined as "Rr= ((R²+ r²) /2) ^½", and

the "L" is the chord length of the blade at this position of representative square mean radius "Rr", and the "b" is the actual length in the radial, span direction of said blade linking the position of the representative hub radius "r" and the position of the representative radius "R", and

an aspect ratio (b/L) of each blade has a shape in a range of "b/L ≤ 1"

in the radial section of each blade, the portion from around the representative square mean radius position of the blade to the position at a tip side of the outer circumference has a concave (2a) curve shaped streamline to the windward side, and the portion from around the representative square mean radius position of the blade to the position at the hub side has a convex (2b) curve shape to the windward side, and

said blades are mutually disposed such that the pitch between said each blade is sufficiently wide to avoid influence of said blade end vortex (33D).

2. The impeller for fan of claim 1,
wherein the chord length of the outer circumference side of each blade is longer than the chord length of the hub side.

3. The impeller for fan of any one of claims 1 or 2,
wherein said blades are disposed symmetrically to the centre of the hub with respect to each other.

4. The impeller for fan of any one of claims 1 or 2,
wherein each blade has a circular front edge (4) and a sharp rear edge (5), and
the shape from the rear edge to the front edge is gradually increased in thickness.

5. The impeller for fan of any one of claims 1 or 2,
wherein each blade has a circular front edge (4) and a sharp rear edge (5), and
the shape from the rear edge to the front edge is nearly same in thickness.

6. The impeller for fan of any one of claims 1or 2,
wherein said blades rotate to admit air from the front edge (4) of the each blade and discharge from the rear edge (5), and
a blade end vortex (33D) generated on the negative pressure surface (8, 8a, 8b) of the each blade is separated from the blade and flows away.

7. The impeller for fan of any one of claims 1or 2, being used in an outdoor unit of an air conditioner.

8. A fan comprising:

a motor (12), and

an impeller (16 ) connected to said motor, said impeller being as specified in any of claims 1 to 7.

9. The fan of claim 8,
wherein the chord length of the outer circumference side of each blade is longer than the chord length of the hub side.

10. The fan of any one of claims 8 or 9,
wherein said impeller has a mixed flow fan.

11. The fan of any one of claims 9 or 10,
wherein said impeller has an axial flow fan.

12. The fan of any one of claims 9 or 10, being used in an outdoor unit of an air conditioner.

13. An air conditioner comprising:

an indoor unit (51),

an outdoor unit (52), and

a piping (53) installed between said indoor unit and outdoor unit,

(a) said outdoor unit having a heat exchanger (54) and a fan (55),

(b) said fan being a fan according to anyone of claims 8 to 12.

Ansprüche

1. Laufrad für Gebläse mit
einer Nabe (3) und zwei an der Nabe angeordneten Flügeln (2), worin die Nabe ein trapezförmiger Körper mit kreisförmigem Querschnitt ist,
dadurch gekennzeichnet, dass
unter der Annahme, dass der kleinste Radius der Kreisgestalt der Nabe "r1" und ihr grösster Radius "r2" sei, ein repräsentativer Nabenradius "r" als "r = (r1 + r2)/2) definiert ist,
unter der weiteren Annahme, dass die Entfernung zwischen der Mitte der Nabe und dem breitesten Vorderende des Flügels "R2" und die Entfernung zwischen der Mitte der Nabe und dem engsten Vorderende des Flügels "R1" sei, ein repräsentativer Radius "R" des Laufrads als "R = (R1 + R2)/2 definiert ist,
ein repräsentativer quadratischer Mittelwert des Radius "Rr" als"Rr = ((r² + r²)/2)^½" definiert ist und
"L" die Sehnenlänge des Flügels an diesem Ort des repräsentativen quadratischen Mittelwerts des Radius "Rr" ist und "b" die tatsächliche Länge des Flügels in der radialen Spannrichtung ist, die den Ort des repräsentativen Nabenradius "r" und den Ort des repräsentativen Radius "R" verbindet,
ein Seitenverhältnis (b/L) jedes Flügels eine Gestalt in einem Bereich von "b/L ≤ 1" besitzt
im radialen Querschnitt jedes Flügels der Abschnitt von ungefähr dem Ort des repräsentativen quadratischen Mittelwerts des Radius des Flügels bis zum Ort an der Seite einer Spitze am Aussenumfang zur Windseite hin eine konkave (2a) Stromliniengestalt besitzt und der Abschnitt von ungefähr dem Ort des repräsentativen quadratischen Mittelwerts des Radius des Flügels bis zum Ort an der Seite der Nabe zur Windseite hin eine konvexe (2b) Kurvengestalt hat, und
die Flügel zueinander so angeordnet sind, dass der Abstand zwischen allen Flügeln genügend gross ist, um einen Einfluss des Wirbels (33D) am Flügelende zu vermeiden.

2. Laufrad für Gebläse nach Anspruch 1,
dadurch gekennzeichnet, dass die Sehnenlänge an der Seite des Aussenumfangs jedes Flügels grösser als die Sehnenlänge an der Seite der Nabe ist.

3. Laufrad für Gebläse nach einem der Ansprüche 1 oder 2,
dadurch gekennzeichnet, dass die Flügel zur Nabenmitte hin symmetrisch zueinander angeordnet sind.

4. Laufrad für Gebläse nach einem der Ansprüche 1 oder 2,
dadurch gekennzeichnet, dass jeder Flügel eine kreisförmige Vorderkante (4) und eine scharfe Hinterkante (5) besitzt und
die Gestalt von der Hinterkante zur Vorderkante allmählich in ihrer Dicke zunimmt.

5. Laufrad für Gebläse nach einem der Ansprüche 1 oder 2,
dadurch gekennzeichnet, dass jeder Flügel eine kreisförmige Vorderkante (4) und eine scharfe Hinterkante (5) besitzt und
die Gestalt von der Hinterkante zur Vorderkante in ihrer Dicke nahezu gleich ist.

6. Laufrad für Gebläse nach einem der Ansprüche 1 oder 2,
dadurch gekennzeichnet, dass sich die Flügel drehen, um Luft von der Vorderkante (4) jedes Flügels anzusaugen und von der Hinterkante (5) auszustossen, und
ein auf der Unterdruckseite (8, 8a, 8b) jedes Flügels am Flügelende erzeugter Wirbel (33D) vom Flügel getrennt wird und wegströmt.

7. Laufrad für Gebläse nach einem der Ansprüche 1 oder 2, der in einer Ausseneinheit einer Klimaanlage verwendet wird.

8. Gebläse mit
einem Motor (12) und
einem an den Motor angeschlossenen Laufrad, wobei das Laufrad wie in einem der Ansprüche 1 bis 7 vorgegeben ist.

9. Gebläse nach Anspruch 8,
dadurch gekennzeichnet, dass die Sehnenlänge an der Seite des Aussenumfangs jedes Flügels grösser als die Sehnenlänge an der Seite der Nabe ist.

10. Gebläse nach einem der Ansprüche 8 oder 9,
dadurch gekennzeichnet, dass das Laufrad ein Diagonalgebläse hat.

11. Gebläse nach einem der Ansprüche 9 oder 10,
dadurch gekennzeichnet, dass das Laufrad ein Axialgebläse hat.

12. Gebläse nach einem der Ansprüche 9 oder 10, das in einer Ausseneinheit einer Klimaanlage verwendet wird.

13. Klimaanlage mit
einer Inneneinheit (51),
einer Ausseneinheit (52) und
zwischen der Inneneinheit und der Ausseneinheit installierten Rohrleitungen (53), wobei

(a) die Ausseneinheit einen Wärmetauscher (54) und ein Gebläse (55) besitzt,

(b) das Gebläse ein Gebläse nach einem der Ansprüche 8 bis 12 ist.

Revendications

1. Roue de ventilateur comprenant :

un moyeu (3) et deux aubes (2) disposées dans ledit moyeu,

dans laquelle ledit moyeu est un corps trapézoïdal possédant une section circulaire,

caractérisée en ce que en supposant que le rayon minimum de la forme circulaire dudit moyeu soit « r1 », et le rayon maximum de celle-ci soit « r2 », un rayon de moyeu représentatif « r » est défini comme « r=(r1+r2)/2 »,

en supposant en outre que la distance depuis le centre dudit moyeu jusqu'à l'extrémité avant la plus large de ladite aube soit « R2 » et la distance depuis le centre dudit moyeu jusqu'à l'extrémité avant la plus petite de ladite aube soit « R1 », un rayon représentatif « R » de la roue est défini comme « R=(R1+R2)/2 »,

un rayon moyen carré représentatif « Rr » est défini comme « Rr= ((R² +r²)/2)^1/2 », et

« L » est la longueur de la corde de l'aube au niveau de cette position du rayon moyen carré représentatif « Rr », et « b » est la longueur réelle dans la direction de la longueur radiale de ladite aube reliant la position du rayon de moyeu représentatif « r » et la position du rayon représentatif « R »,

un rapport de longueur (b/L) de chaque aube présente une forme dans une plage de « b/L ≤ 1 »

dans la section radiale de chaque aube, la partie située entre le pourtour de la position du rayon moyen carré représentatif de l'aube et la position au niveau d'un côté en pointe de la circonférence externe présente une courbe concave (2a) de forme aérodynamique sur le côté au vent, et la partie située entre le pourtour de la position du rayon moyen carré représentatif de l'aube et la position au niveau du côté de moyeu possède une forme de courbe convexe (2b) du côté au vent, et

lesdites aubes sont mutuellement disposées de telle sorte que le pas entre chaque aube est suffisamment large pour éviter une influence d'un vortex (33D) à l'extrémité de ladite aube.

2. Roue de ventilateur selon la revendication 1,
dans laquelle la longueur de la corde du côté de la circonférence externe de chaque aube est plus longue que la longueur de la corde du côté du moyeu.

3. Roue de ventilateur selon l'une quelconque des revendication 1 ou 2,
dans laquelle lesdites aubes sont disposées symétriquement au centre du moyeu les unes par rapport aux autres.

4. Roue de ventilateur selon l'une quelconque des revendications 1 ou 2,
dans laquelle chaque aube possède une arête avant circulaire (4) et une arête arrière vive (5), et
la forme entre l'arête arrière et l'arête avant augmente progressivement en épaisseur.

5. Roue de ventilateur selon l'une quelconque des revendications 1 ou 2,
dans laquelle chaque aube possède une arête avant circulaire (4) et une arête arrière vive (5), et
la forme entre l'arête arrière et l'arête avant est pratiquement la même en épaisseur.

6. Roue de ventilateur selon l'une quelconque des revendications 1 ou 2,
dans laquelle lesdites aubes tournent pour laisser passer l'air depuis l'arête avant (4) de chaque aube et l'évacuer depuis l'arête arrière (5), et
un vortex d'extrémité d'aube (33D) généré sur la surface de dépression (8, 8a, 8b) de chaque aube est séparé de l'aube et circule plus loin.

7. Roue de ventilateur selon l'une quelconque des revendications 1 ou 2, étant utilisée dans une unité extérieure d'un système de climatisation.

8. Ventilateur comprenant :

un moteur (12), et

une roue connectée audit moteur, ladite roue étant définie dans l'une quelconque des revendications 1 à 7.

9. Ventilateur selon la revendication 8,
dans lequel la longueur de la corde du côté de circonférence externe de chaque aube est plus longue que la longueur de la corde du côté du moyeu.

10. Ventilateur selon l'une quelconque des revendications 8 ou 9,
dans lequel ladite roue possède un ventilateur à flux mixte.

11. Ventilateur selon l'une quelconque des revendications 9 ou 10,
dans lequel ladite roue possède un ventilateur à flux axial.

12. Ventilateur selon l'une quelconque des revendications 9 ou 10, étant utilisé dans une unité extérieure d'un système de climatisation.

13. Système de climatisation comprenant :

une unité intérieure (51),

une unité extérieure (52), et

une canalisation (53) installée entre ladite unité intérieure et ladite unité extérieure,

(a) ladite unité extérieure possédant un échangeur thermique (54) et un ventilateur (55),

(b) ledit ventilateur étant un ventilateur selon l'une quelconque des revendications 8 à 12.

Drawing