CONNECTED CARS

Abstract

 The object of the present invention is to enable connected cars to achieve both good performance while traveling a straight line at a high speed and good performance while traveling a sharp curve at a low speed. In the case of traveling a sharp curve at a low speed, motors of two electromagnetic dampers are connected to a common circuit to convert thermal energy in series. When the connected cars travel along a track in this state, yawing occurs between the cars A and B. In this instance, since the electromagnetic dampers 21 and 22 are shrunk (or extended) by the same amount, the motors rotate in the same direction, and no electric current flows and no damping force is generated. Consequently, there is no resistance to the yawing, and the connected cars perform yawing freely. In the case where hunting occurs, since one of the electromagnetic dampers 21 and 22 is shrunk and the other is extended, the motors rotate in opposite directions. When the motors rotate in opposite directions, electric current flows in the circuit so as to be converted into thermal energy and damping force is generated. Consequently, hunting can be controlled.

Description

Technical Field

[0001] The present invention relates to connected cars in which two cars are longitudinally connected.

Background Art

[0002] Patent Document 1 has proposed a structure in which a truck is provided in a connecting section of two longitudinally-connected cars. According to FIG. 6 and its related description of Patent Document 1, a truck is provided on a connecting section of two longitudinally-connected cars, and an actuator is provided between the frame of the truck and each of the two cars so as to assist self-steering by activating the actuator.

[0003] Patent Document 2 has disclosed that a single axle truck is provided at the end of one of two longitudinally-connected cars rather than in a connecting section of the two cars, the single axle truck and the other car are connected by a link, and a damper is provided between the axle box of the truck and the car body so as to control lateral movement of the truck. With this, it is possible to prevent excessive displacement of the lateral direction between the car body and the wheel axle.

[0004] Patent Document 3 has disclosed an electromagnetic damper as a damper for a car. The electromagnetic damper has a DC (direct current) motor inside, and a rotor or a stator of the motor is rotated by linear movement of a cylinder or swinging movement of an arm. Electromotive force generated in a solenoid by electromagnetic induction is converted into damping force.

Patent Document 1: Japanese Patent Application Publication No. 2002-87262, paragraph 0012 and FIG. 6

Patent Document 2: Japanese Patent Application Publication No. 2001-63567, paragraphs 0019 and 0024

Patent Document 3: Japanese Patent Application Publication No. 2003-227543, paragraphs 000 and 0002

Disclosure of the Invention

Problems to be solved by the Invention

[0005] Railroad cars require travel stability and the ability to yaw on curves. However, it is difficult to achieve both travel stability at a high speed and yawing on sharp curves at a low speed. This is a problem to be solved.

[0006] For example, in Patent Document 1, activation of the actuator allows the truck provided in the connecting section of the cars to perform self-steering. However, it is impossible to achieve a damping effect between the cars with respect to yawing. If a damper is provided instead of the actuator, lateral pressure increases when passing through a sharp curve.

[0007] Also, if a damper for controlling lateral movement of a truck is provided as disclosed in Patent Document 2, it is impossible to achieve a damping effect between the cars with respect to yawing. In Patent Document 3, there is no description of connected cars.

Means for solving the problems

[0008] The object of the present invention is to achieve both travel stability and yawing on sharp curves in connected cars.

[0009] In order to solve the above-mentioned problems, according to the present invention, there are provided connected cars comprising cars which are longitudinally connected, and an electromagnetic damper which is provided in a connecting section between the cars, wherein the rigidity of the electromagnetic damper in the connecting section is adjusted to be high at the time of traveling at a high speed or traveling a straight line, and the rigidity of the electromagnetic damper in the connecting section is adjusted to be low at the time of traveling at a low speed or traveling on a curve.

[0010] According to the present invention, there are also provided connected cars comprising two cars which are longitudinally connected, a truck which is provided in a connecting section between the cars, and an electromagnetic damper which is provided between a frame or a bolster of the truck and each of the cars, wherein a motor including a DC motor is installed into each of the electromagnetic dampers, and the motors are connected to separate external circuits and a common external circuit for converting electromotive force generated by electromagnetic induction into thermal energy including motion damping force in a switchable manner.

[0011] In the above-mentioned structure, in the case where the motors of the electromagnetic dampers are connected to the separate circuits for conversion into thermal energy, the electromagnetic dampers can perform a damping function individually. In the case where the motors of the electromagnetic dampers are connected to the common external circuit in series, electromotive force is not generated when each motor rotates in the same direction, and electromotive force is generated when each motor rotates in a different direction, which causes electric current to flow and be converted into thermal energy,

[0012] As for switching the circuits, for example, the motors are connected to the separate circuits at the time of traveling at a high speed or traveling in a straight line, while the motors are connected to the common circuit at the time of traveling at a low speed or traveling around a sharp curve.

[0013] Regarding the truck, either a single axle truck or a monocycle independently-rotatable truck may be used. A direct-acting type damper or a rotating type damper can be used as a form of the electromagnetic damper.

Effect of the Invention

[0014] According to the present invention, since an electromagnetic damper is provided so as to couple the frame or the bolster of a truck provided in a connecting section between cars and each of the cars, and separate external circuits for converting electromotive force generated by electromagnetic induction into thermal energy and a common external circuit for converting electromotive force generated by electromagnetic induction into thermal energy can be switched selectively as a circuit to which a motor installed in the electromagnetic damper is connected, it is possible to serve as a damper only when it is needed.

[0015] Consequently, it is possible to provide both stability while traveling in a straight line at a high speed and yawing performance while traveling a sharp curve.

Brief Description of the Drawings

[0016] 

Figure 1 is a side view of connected cars according to the present invention;

Figure 2 is an enlarged side view of the coupling portion of a truck and longitudinally-connected cars;

Figure 3 is a schematic view of the structure of Figure 2;

Figure 4 is a cross-sectional view of a direct-acting type electromagnetic damper;

Figure 5 shows another embodiment in the same manner as Figure 3;

Figure 6 shows another embodiment in the same manner as Figure 3;

Figure 7 shows another embodiment in the same manner as Figure 3;

Figure 8 shows another embodiment in the same manner as Figure 3;

Figure 9 shows another embodiment in the same manner as Figure 3;

Figures 10 (a) - (c) are plan views of connected cars in various travel conditions;

Figure 11 (a) is a view showing a state where motors of two electromagnetic dampers are connected to separate circuits for conversion into thermal energy; and Figure 11 (b) is a view showing a state where motors of two electromagnetic dampers are connected to a common circuit for conversion into thermal energy in series; and

Figure 12 (a) is a view showing the circuit in the state of Figure 11 (b) in a case where the two motors rotate in the same direction, and Figure 12 (b) is a view showing the circuit in the state of Figure 11 (b) in a case where the two motors rotate in opposite directions.

Best Mode for Carrying Out the Invention

[0017] Embodiments of the present invention are described below by referring to the attached drawings. Figure 1 is a side view of intermediately-connected cars with three axles which are connected cars according to the present invention, Figure 2 is an enlarged side view of the coupling portion of a truck and longitudinally-connected cars, and Figure 3 is a schematic view of the structure of Figure 2.

[0018] The intermediately-connected cars with three axles are comprised of a single axle truck 1 provided in the coupling portion between two cars A and B, and single axle trucks 2 and 3 are provided in the cars A and B, respectively. In the single axle truck 1, a wheel axle is constructed of an axle 10 and a pair of left and right wheels 11 attached to the axle 10. Both ends of the axle 10 are supported by an axle box 12 in a rotatable manner. A frame 14 of the truck is supported on the axle box 12 by a damping rubber 13 having high rigidity. A bolster 16 is supported on the frame 14 by springs 15. The bolster 16 and the car A are coupled by a bolster anchor 17, and the cars A and B are coupled by a center pin 18.

[0019] Further, the frame 14 and the bolster 16 are coupled in a rotatable manner by a pin 19. The frame 14 and the bolster 16 may be coupled by a parallel linkage instead of the pin 19.

[0020] Further, electromagnetic dampers 21 and 22 are interposed between the frame 14 and the car A and between the frame 14 and the car B, respectively. Electromagnetic dampers 23 and 24 are provided between the frames of the single axle trucks 2 and 3 and the cars A and B. Since the frame 14 can rotate relatively to the bolster 16, and the frame 14 is coupled to the cars with the electromagnetic dampers 21 and 22, it is possible to control hunting by using the damping force in the direction of rotation generated by the extension and shrinkage of the electromagnetic dampers.

[0021] As shown in FIG. 4, the electromagnetic dampers 21-24 are comprised of a cylinder 30, and a piston 31 inserted into the cylinder 30 in a slidable manner. A DC motor 32, a reduction gear 33, a ball screw 34 and a nut 35 are incorporated into the cylinder 30. Coupling portions 36, 37 are provided at ends of the cylinder 30 and the piston 31. In the electromagnetic dampers 21 and 22, the coupling portion 36 is coupled to the car A or B, and the coupling portion 37 is coupled to the frame 14, respectively.

[0022] Figures 5-9 show another embodiment in the same manner as Figure 3. In the embodiment of Figure 5, the cars A and B are coupled by a coupler 25, and the cars A and B are supported at two points by the bolster 16.

[0023] In the embodiment of Figure 6, the car A and the bolster 16 are coupled by the bolster anchor 17. The electromagnetic damper 21 is interposed between the bolster 16 and the frame 14, and the electromagnetic damper 22 is interposed between the car B and the frame 14.

[0024] The above-mentioned embodiments of Figure 5 and Figure 6 use a direct-mount type in which the bolster 16 is directly provided on the frame 14. In contrast, another embodiment of Figure 7 uses an indirect-mount type in which the bolster anchor 17 is interposed between the frame 14 and the bolster 16, the electromagnetic damper 21 is interposed between the bolster 16 and the car A, and the electromagnetic damper 22 is interposed between the bolster 16 and the car B.

[0025] Another embodiment of Figure 8 also uses an indirect-mount type. In this embodiment, the electromagnetic damper 21 is interposed between the frame 14 and the car A, and the electromagnetic damper 22 is interposed between the frame 14 and the car B.

[0026] In another embodiment of Figure 9, the electromagnetic damper 21 is interposed between the frame 14 and the car A, and the electromagnetic damper 22 is interposed between the bolster 16 and the car B.

[0027] Figures 10 (a) is a plan view of the connected cars at the time of traveling a straight line. The electromagnetic dampers 21 and 22 are not extended and shrunk in this state. Figure 10 (b) is a plan view of the connected cars at the time of traveling a curve. The electromagnetic dampers 21 and 22 are extended and shrunk at the same time in this state. Figure 10 (c) is a plan view of the connected cars hunting. One of the electromagnetic dampers 21 and 22 is extended, and the other is shrunk in this state.

[0028] Next, the operation of the electromagnetic dampers 21 and 22 will be explained. Figure 11 (a) is a view showing a state where motors of two electromagnetic dampers are connected to separate circuits for conversion into thermal energy, and Figure 11 (b) is a view showing a state where motors of two electromagnetic dampers are connected to a common circuit for conversion into thermal energy in series, Figure 12 (a) is a view showing the circuit in the state of Figure 11 (b) in a case where the two motors rotate in the same direction, and Figure 12 (b) is a view showing the circuit in the state of Figure 11 (b) in a case where the two motors rotate in opposite directions.

[0029] In the case of traveling a straight line at a high speed as shown in Figure 10 (a), the motors of the two electromagnetic dampers are connected to the separate circuits for conversion into thermal energy as shown in Figure 11 (a). With this, the electromagnetic dampers 21 and 22 serve as an independent damper.

[0030] On the other hand, in the case of traveling a sharp curve at a low speed, the motors of the two electromagnetic dampers are connected to the common circuit for conversion into thermal energy in series as shown in Figure 11 (b). When the connected cars travel along a track in this state, yawing occurs between the cars A and B as shown in Figure 10 (b). In this instance, since the electromagnetic dampers 21 and 22 are shrunk (or extended) by the same amount, the motors rotate in the same direction. When the motors rotate in the same direction, no electric current flows and no damping force is generated as shown in Figure 12 (a). Consequently, there is no resistance to the yawing, and the connected cars perform yawing freely.

[0031] When the connected cars travel a sharp curve at a low speed, hunting easily occurs as shown in Figure 11 (c). In this instance, since one of the electromagnetic dampers 21 and 22 is shrunk and the other is extended, the motors rotate in opposite directions. When the motors rotate in opposite directions, electric current flows in the circuit so as to be converted into thermal energy and damping force is generated as shown in Figure 12 (b). Consequently, hunting can be controlled.

[0032] In the embodiments shown in the figures, the electromagnetic dampers 21 and 22 are provided on one side. However, it is possible to provide the electromagnetic dampers 21 and 22 separately to the left and right. In this instance, since the shrinkage direction of the electromagnetic dampers 21 and 22 are reverse to each other, it is necessary to modify the structure of the circuit In any case, the point is to exert damping force on hunting of the truck, and prevent damping force from being generated on yawing between the cars.

[0033] Also, as for the arrangement of the electromagnetic dampers, it is possible to provide two electromagnetic dampers only on one side or provide one electromagnetic damper on each side (dot symmetry). In addition, although the electromagnetic damper is provided between the frame and the car directly or indirectly in the embodiments, it may be provided between the cars.

Claims

1. Connected cars comprising:

cars which are longitudinally connected; and

an electromagnetic damper which is provided in a connecting section between the cars,

wherein the rigidity of the electromagnetic damper in the connecting section is adjusted to be high at the time of traveling at a high speed or traveling a straight line, and the rigidity of the electromagnetic damper in the connecting section is adjusted to be low at the time of traveling at a low speed or traveling a curve.

2. Connected cars comprising
two cars which are longitudinally connected;
a truck which is provided in a connecting section between the cars; and
an electromagnetic damper which is provided between a frame or a bolster of the truck and each of the cars,
wherein a motor including a DC motor is installed into each of the electromagnetic dampers, and the motors are connected to separate external circuits and a common external circuit for converting electromotive force generated by electromagnetic induction into thermal energy including motion damping force in a switchable manner.

3. The connected cars according to claim 1 or 2, wherein the motors are connected to the separate circuits at the time of traveling at a high speed or traveling a straight line, while the motors are connected to the common circuit at the time of traveling at a low speed or traveling a sharp curve.

4. The connected cars according to claim.1 or 2, wherein the truck is a single axle truck, and the electromagnetic damper is a direct-acting type damper or a rotating type damper.

Drawing