Rail vehicle bogie

Abstract

To provide a rail vehicle bogie capable of suppressing wheel flange wear with a simple structure.SOLUTION: A bogie (20) includes a bogie frame (21), a bolster (23), a front shaft (25), a rear shaft (26), front shaft boxes (27L, 27R), rear shaft boxes (28L, 28R), a front link mechanism (30), and a rear link mechanism (40). The front link mechanism (30) connects one front shaft housing (27L) to the bolster (23). The rear link mechanism (40) connects the rear shaft housing (28R), positioned opposite the front link mechanism (30), to the bolster (23). The front link mechanism (30) includes a front lever, a first front link connecting the front shaft box (27L) and the front lever, and a second front link connecting the bolster (23) and the front lever. The rear link mechanism (40) includes a rear lever, a first rear link connecting the rear shaft box (28R) and the rear lever, and a second rear link connecting the bolster (23) and the rear lever.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to bogies for rail vehicles. [Background technology]

[0002] A railway vehicle comprises a bogie and a carbody supported on the bogie, and travels on rails. For example, a direct-mount bogie is used for the railway vehicle. The bogie comprises a bogie frame, a bolster extending in the left-right direction, and wheel sets provided at the front and rear of the bogie frame relative to the bolster. The carbody is supported on the bolster via a pair of air springs on the left and right. The bolster is supported on the bogie frame via a center pan and a pair of side bearings on the left and right. The bogie frame is rotatable relative to the bolster.

[0003] When a railway vehicle travels on a curved road, the wheels generate a force (lateral force) pushing against the rails in the left and right directions. Patent Document 1, for example, is known as a technology for reducing lateral force at the exit of a curved road. Patent Document 1 discloses a bogie (steering bogie) in which the front and rear wheelsets are steered. The steering bogie described in Patent Document 1 is equipped with steering devices that are provided on the left and right sides of the bogie frame and intentionally rotate the front and rear wheelsets. The left and right steering devices each include a lever supported on the bogie frame and three links. The first link connects the bolster to the lever. The second link connects the axle box of the front wheelset to the lever. The third link connects the axle box of the rear wheelset to the lever.

[0004] When a railway vehicle equipped with a steering bogie passes through a curved section, the rotation of a bolster integrated with the car body in each steering device causes a lever to rotate via the first link. The rotation of the lever causes the second link and the third link to move longitudinally in opposite directions. The front wheelset is steered by the longitudinal movement of the second link, and the rear wheelset is steered by the longitudinal movement of the third link. In the steering bogie described in Patent Document 1, each wheelset is steered so that the steering angle of the front wheelset is larger than the steering angle of the rear wheelset. Patent Document 1 describes that immediately after the railway vehicle passes through a curved section, a state in which the steering angle of the wheelset becomes excessively large relative to the track (oversteering state) is suppressed, thereby reducing lateral force. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5765432 Summary of the Invention [Problem to be solved by the invention]

[0006] When passing through a curved road, the bogie frame rotates relative to the bolster. The angle between the bolster (car body) and the bogie frame is also called the bogie angle. When a railway vehicle enters a straight road from a curved road and the bogie angle remains, that is, when the bogie frame remains tilted relative to the bolster, the wheelset is tilted relative to the rail. In this case, one wheel contacts the rail near the flange, while the other wheel contacts the rail at a position away from the flange. Generally, the wheel diameter increases as it approaches the flange, resulting in a difference in the diameter of the contact area with the rail between the left and right wheels. As a result, each of the front and rear wheelsets is subjected to a longitudinal creep force. The longitudinal creep force acts on the front wheelset in a direction that reduces the bogie angle. On the other hand, the longitudinal creep force acts on the rear wheelset in a direction that increases the bogie angle.

[0007] If the longitudinal creep force on the wheelset is greater than the frictional force between the side bearing and the bogie frame, the bogie frame will rotate relative to the bolster to reduce the bogie angle, and the bogie frame will remain in a straight line. However, depending on the bogie, the weight of the car body supported by the side bearing relative to the total weight of the car body, i.e., the side bearing's load ratio, may be large. In this case, the frictional force between the side bearing and the bogie frame may become large, preventing the bogie frame from returning to its original position, and the bogie angle may remain. This may cause the flange of the wheel on the inner rail of the front wheelset of the leading bogie to come into contact with the rail, making the flange more susceptible to wear.

[0008] In order to reduce the remaining bogie angle when a railway vehicle enters a straight track from a curved track, it is possible to provide a steering device such as that described in Patent Document 1 to the bogie. However, in this case, the number of parts in the entire railway vehicle increases compared to a case in which a steering device is not provided. From the viewpoint of reducing the weight of the railway vehicle and reducing the cost of parts, it is preferable to keep the number of parts as small as possible.

[0009] An object of the present disclosure is to provide a bogie for a railway vehicle that can suppress wheel flange wear with a simple configuration. [Means for solving the problem]

[0010] A bogie for a railway vehicle according to the present disclosure includes a bogie frame, a bolster, two side bearings, a front wheelset, a rear wheelset, two front axle boxes, two rear axle boxes, a front link mechanism, and a rear link mechanism. The bolster extends in the left-right direction of the bogie. The two side bearings are arranged on the bogie frame with a gap between them in the left-right direction and support the bolster. The front wheelset is provided in front of the bogie frame with respect to the bolster. The rear wheelset is provided on the rear of the bogie frame with respect to the bolster. The two front axle boxes are arranged at the left and right ends of the front wheelset, respectively. The two rear axle boxes are arranged at the left and right ends of the rear axle, respectively. The front link mechanism connects one of the two front axle boxes to the bolster. The rear link mechanism connects the rear axle box, which is arranged on the left-right opposite side of the front link mechanism, to the bolster. The front link mechanism includes a front lever rotatably supported on the bogie frame, a first front link connecting the front axle box and the front lever, and a second front link connecting the bolster and the front lever. The connection portion between the first front link and the front lever is located on the opposite side of the support portion between the bogie frame and the front lever from the connection portion between the second front link and the front lever in the vertical direction of the railway vehicle. The rear link mechanism includes a rear lever rotatably supported on the bogie frame, a first rear link connecting the rear axle box and the rear lever, and a second rear link connecting the bolster and the rear lever. The connection portion between the first rear link and the rear lever is located on the same side of the support portion between the bogie frame and the rear lever as the connection portion between the second rear link and the rear lever in the vertical direction. [Effects of the Invention]

[0011] According to the bogie for a railway vehicle according to the present disclosure, wear on the wheel flanges can be suppressed with a simple configuration. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a top view that schematically shows a railway vehicle equipped with a bogie according to an embodiment. [Figure 2] FIG. 2 is a left side view of the railway vehicle. [Figure 3] FIG. 3 is a right side view of the railway vehicle. [Figure 4] FIG. 4 is a top view of a railway vehicle. [Figure 5] FIG. 5 is a top view of a railway vehicle. [Figure 6] FIG. 6 is a top view that schematically shows a railway vehicle equipped with a bogie according to a modified example. [Figure 7] FIG. 7 is a top view that schematically shows a railway vehicle equipped with a bogie according to a modified example. [Figure 8] FIG. 8 is a top view that schematically shows a railway vehicle equipped with a bogie according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0013] A bogie for a railway vehicle according to an embodiment includes a bogie frame, a bolster, two side bearings, a front wheelset, a rear wheelset, two front axle boxes, two rear axle boxes, a front link mechanism, and a rear link mechanism. The bolster extends in the left-right direction of the bogie. The two side bearings are arranged on the bogie frame with a gap between them in the left-right direction and support the bolster. The front wheelset is located in front of the bogie frame with respect to the bolster. The rear wheelset is located on the rear of the bogie frame with respect to the bolster. The two front axle boxes are located at the left and right ends of the front wheelset, respectively. The two rear axle boxes are located at the left and right ends of the rear axle, respectively. The front link mechanism connects one of the two front axle boxes to the bolster. The rear link mechanism connects the rear axle box, which is located on the left-right opposite side of the front link mechanism, to the bolster. The front link mechanism includes a front lever rotatably supported on the bogie frame, a first front link connecting the front axle box and the front lever, and a second front link connecting the bolster and the front lever. The connection portion between the first front link and the front lever is located on the opposite side of the support portion between the bogie frame and the front lever from the connection portion between the second front link and the front lever in the vertical direction of the railway vehicle. The rear link mechanism includes a rear lever rotatably supported on the bogie frame, a first rear link connecting the rear axle box and the rear lever, and a second rear link connecting the bolster and the rear lever. The connection portion between the first rear link and the rear lever is located on the same side of the support portion between the bogie frame and the rear lever as the connection portion between the second rear link and the rear lever in the vertical direction (first configuration).

[0014] When a railway vehicle equipped with a bogie according to the embodiment enters a straight road from a curved road, if the bogie frame, front wheelset, and rear wheelset are tilted relative to the bolster, the rear wheelset receives a force from the rear link mechanism in a direction that moves it closer to the lateral center. As a result, the longitudinal creep force acting on the rear wheelset is reduced, the rear wheelset is moved toward the lateral center, and the tilt of the rear wheelset relative to the bolster is eliminated. At the same time, a longitudinal creep force acts on the front wheelset in a direction that reduces the bogie angle. Furthermore, this longitudinal creep force is also applied to the bogie frame via the front link mechanism. As a result, the tilt of the front wheelset and bogie frame relative to the bolster is eliminated. As described above, the bogie angle can be reduced with the bogie frame according to the embodiment, thereby suppressing wheel flange wear.

[0015] Furthermore, the bogie angle is reduced using a front link mechanism and a rear link mechanism in the bogie according to the embodiment. The front link mechanism and the rear link mechanism are arranged point-symmetrically with each other. Specifically, the front link mechanism connects one of the two front axle boxes to the bolster. The rear link mechanism connects the rear axle box, which is located on the opposite side of the front link mechanism in the left-right direction, to the bolster. In this case, the number of parts is smaller than when each link mechanism connects both the front and rear axle boxes to the bolster. Therefore, the bogie according to the embodiment can suppress wheel flange wear with a simple configuration.

[0016] In the bogie of the first configuration, preferably, the distance in the left-right direction from the connection between the second front link and the bolster to the connection between the second rear link and the bolster is smaller than the distance in the left-right direction from the connection between the second front link and the front lever to the connection between the second rear link and the rear lever (second configuration).

[0017] In the bogie of the above configuration, preferably, the left-right distance from the connection between the first front link and the front axle box to the connection between the first rear link and the rear axle box is greater than the left-right distance from the connection between the second front link and the front lever to the connection between the second rear link and the rear lever (third configuration).

[0018] In the bogie having the above configuration, the leverage ratio of each of the front link mechanism and the rear link mechanism may be less than 6 (fourth configuration).

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the same or equivalent components are designated by the same reference numerals, and the same description will not be repeated.

[0020] [Cart] Fig. 1 is a top view that schematically shows a railway vehicle 10 equipped with a bogie 20 according to this embodiment. In Fig. 1, the railway vehicle 10 runs on rails 1. In this specification, the direction of travel of the railway vehicle 10 may be referred to as the fore-and-aft direction, the width direction of the railway vehicle 10 may be referred to as the left-and-right direction, and the height direction of the railway vehicle 10 may be referred to as the up-and-down direction.

[0021] The railway vehicle 10 comprises a car body (not shown), a bogie 20 arranged at the front of the car body, and a bogie (not shown) arranged at the rear of the car body. Each bogie supports the car body. FIG. 1 shows the front bogie 20. The rear bogie has a shape symmetrical to the bogie 20 in the fore-and-aft direction, for example. In this embodiment, the bogie 20 is a direct-mount bogie.

[0022] Referring to Figure 1, the bogie 20 includes a bogie frame 21, air springs 22L, 22R arranged on the left and right sides of the bogie frame 21, a bolster 23, two side bearings 24L, 24R, a front wheel axle 25, a rear wheel axle 26, two front axle boxes 27L, 27R, and two rear axle boxes 28L, 28R.

[0023] The left and right air springs 22L, 22R are arranged on the bolster 23 with a gap between them in the left-right direction. The air springs 22L, 22R support the car body and reduce vibrations of the car body. The bolster 23 extends in the left-right direction. Two side bearings 24L, 24R are arranged on the bogie frame 21 with a gap between them in the left-right direction and support the bolster 23. The side bearings 24L, 24R are provided, for example, on the left and right side beams of the bogie frame 21 and are in contact with the bolster 23.

[0024] A center pan (not shown) may be provided between the bogie frame 21 and the bolster 23. The center pan supports the center of the bolster 23. The bogie frame 21 is rotatable relative to the bolster 23 around the center pan.

[0025] The front wheel set 25 is provided on the front side of the bogie frame 21 with respect to the bolster 23. The front wheel set 25 has a pair of left and right wheels 251L, 251R and an axle 252 extending in the left-right direction. The left and right wheels 251L, 251R are fixed to both ends of the axle 252, respectively.

[0026] The front axle boxes 27L, 27R are respectively disposed at the left and right ends of the front wheel set 25. The axle 252 is rotatably supported by bearings (not shown) provided in each of the front axle boxes 27L, 27R.

[0027] The rear wheel axle 26 is provided on the rear side of the bogie frame 21 with respect to the bolster 23. The rear wheel axle 26 has a pair of left and right wheels 261L, 261R and an axle 262 extending in the left-right direction. The left and right wheels 261L, 261R are fixed to both ends of the axle 262, respectively.

[0028] The rear axle boxes 28L, 28R are respectively disposed at the left and right ends of the rear wheel axle 26. The axle 262 is rotatably supported by bearings (not shown) provided in each of the rear axle boxes 28L, 28R.

[0029] In the bogie 20 according to this embodiment, the coefficient of friction between the side bearings 24L, 24R and the bolster 23 is set to be relatively large. The coefficient of friction between the side bearings 24L, 24R and the bolster 23 relative to the coefficient of friction between the wheels 251L, 251R, 261L, 261R and the rail 1 is greater than, for example, 0.43.

[0030] The bogie 20 further includes a front link mechanism 30 and a rear link mechanism 40. Fig. 2 is a left side view of the railway vehicle 10. Fig. 3 is a right side view of the railway vehicle 10. Fig. 2 shows the front link mechanism 30, and Fig. 3 shows the rear link mechanism 40.

[0031] 1 and 2, the front link mechanism 30 connects one of the two front axle boxes 27L, 27R to the bolster 23. In this embodiment, the front link mechanism 30 connects the left front axle box 27L to the vicinity of the left end of the bolster 23.

[0032] The front link mechanism 30 includes a front lever 31, a first front link 32, and a second front link 33. The front lever 31 extends generally in the vertical direction. The front lever 31 is supported by the bogie frame 21 at a support portion 31a. The position of the support portion 31a is a fixed point with respect to the bogie frame 21. The front lever 31 is rotatable around the support portion 31a.

[0033] The first front link 32 and the second front link 33 each extend generally in the front-to-rear direction. The first front link 32 connects the left front axle box 27L and the front lever 31. The first front link 32 is supported by the front axle box 27L at a connection portion 32a. The position of the connection portion 32a is a fixed point relative to the front axle box 27L. The first front link 32 is rotatable around the connection portion 32a.

[0034] The method of connecting the first front link 32 to the left front axle box 27L and the front lever 31 is not particularly limited. In this embodiment, holes 321, 322 are formed at both ends of the first front link 32. The hole 321 is provided at the end on the front axle box 27L side, and the hole 322 is provided at the end on the front lever 31 side. A shaft 323 is inserted into the hole 321, and one end of the shaft 323 is fixed to the left side surface of the front axle box 27L. This forms a connection portion 32a. A shaft 324 is inserted into the hole 322, and one end of the shaft 324 is fixed to the side surface of the front lever 31. This forms a connection portion 32b between the first front link 32 and the front lever 31. The connection portion 32b is movable as the front lever 31 rotates.

[0035] The second front link 33 connects the bolster 23 and the front lever 31. The second front link 33 is supported by the bolster 23 at a connection portion 33a. The position of the connection portion 33a is a fixed point with respect to the bolster 23. The second front link 33 is rotatable around the connection portion 33a.

[0036] The method of connecting the second front link 33 to the bolster 23 and the front lever 31 is not particularly limited. In this embodiment, holes 331 and 332 are formed at both ends of the second front link 33. The hole 331 is provided at the end on the bolster 23 side, and the hole 332 is provided at the end on the front lever 31 side. A shaft 333 is inserted into the hole 331, and one end of the shaft 333 is fixed to the left side surface of the bolster 23. This forms a connection portion 33a. A shaft 334 is inserted into the hole 332, and one end of the shaft 334 is fixed to the side surface of the front lever 31. This forms a connection portion 33b between the second front link 33 and the front lever 31. The connection portion 33b is movable in accordance with the rotation of the front lever 31.

[0037] In the vertical direction, the connection portion 32b between the first front link 32 and the front lever 31 is located on the opposite side of the support portion 31a between the bogie frame 21 and the front lever 31 from the connection portion 33b between the second front link 33 and the front lever 31. Specifically, the connection portion 33b, the support portion 31a, and the connection portion 32b are provided in this order from above. In other words, the support portion 31a is provided between the connection portion 32b and the connection portion 33b in the vertical direction.

[0038] 1 and 3, the rear link mechanism 40 connects one of the two rear axle boxes 28L, 28R to the bolster 23. Specifically, the rear link mechanism 40 connects the rear axle box 28R, which is located on the opposite side of the front link mechanism 30 in the left-right direction, to the bolster 23. In other words, the rear link mechanism 40 is arranged point-symmetrically with the front link mechanism 30 with respect to the center (center pan) of the bogie 20. In this embodiment, the front link mechanism 30 is arranged on the left side, and therefore the rear link mechanism 40 connects the right rear axle box 28R to the vicinity of the right end of the bolster 23. The rear link mechanism 40 has a configuration slightly different from that of the front link mechanism 30.

[0039] The rear link mechanism 40 includes a rear lever 41, a first rear link 42, and a second rear link 43. The rear lever 41 extends generally in the vertical direction. The rear lever 41 is supported by the bogie frame 21 at a support portion 41a. The position of the support portion 41a is a fixed point with respect to the bogie frame 21. The rear lever 41 is rotatable around the support portion 41a.

[0040] The first rear link 42 and the second rear link 43 each extend generally in the front-to-rear direction. The first rear link 42 connects the right rear axle box 28R and the rear lever 41. The first rear link 42 is supported by the rear axle box 28R at a connection portion 42a. The position of the connection portion 42a is a fixed point relative to the rear axle box 28R. The first rear link 42 is rotatable around the connection portion 42a.

[0041] The method of connecting the first rear link 42 to the right rear axle box 28R and the rear lever 41 is not particularly limited. In the example of this embodiment, holes 421, 422 are formed at both ends of the first rear link 42. The hole 421 is provided at the end on the rear axle box 28R side, and the hole 422 is provided at the end on the rear lever 41 side. An axle 423 is inserted into the hole 421, and one end of the axle 423 is fixed to the right side surface of the rear axle box 28R. This forms a connection part 42a. Furthermore, an axle 424 is inserted into the hole 422, and one end of the axle 424 is fixed to the side surface of the rear lever 41. This forms a connection part 42b between the first rear link 42 and the rear lever 41. The connection part 42b is movable in accordance with the rotation of the rear lever 41.

[0042] The second rear link 43 connects the bolster 23 and the rear lever 41. The second rear link 43 is supported by the bolster 23 at a connection portion 43a. The position of the connection portion 43a is a fixed point with respect to the bolster 23. The second rear link 43 is rotatable around the connection portion 43a.

[0043] The method of connecting the second rear link 43 to the bolster 23 and the rear lever 41 is not particularly limited. In this embodiment, holes 431 and 432 are formed at both ends of the second rear link 43. The hole 431 is provided at the end on the bolster 23 side, and the hole 432 is provided at the end on the rear lever 41 side. A shaft 433 is inserted into the hole 431, and one end of the shaft 433 is fixed to the right side surface of the bolster 23. This forms a connection portion 43a. A shaft 434 is inserted into the hole 432, and one end of the shaft 434 is fixed to the side surface of the rear lever 41. This forms a connection portion 43b between the second rear link 43 and the rear lever 41. The connection portion 43b is movable in accordance with the rotation of the rear lever 41.

[0044] As described above, in the front link mechanism 30, the connection portion 32b between the first front link 32 and the front lever 31 is located on the opposite side of the support portion 31a between the bogie frame 21 and the front lever 31 from the connection portion 33b between the second front link 33 and the front lever 31 in the vertical direction. On the other hand, in the rear link mechanism 40, the connection portion 42b between the first rear link 42 and the rear lever 41 is located on the same side of the support portion 41a between the bogie frame 21 and the rear lever 41 as the connection portion 43b between the second rear link 43 and the rear lever 41 in the vertical direction. Specifically, the connection portion 43b, the connection portion 42b, and the support portion 41a are provided in this order from top to bottom. In other words, the support portion 41a is provided below both the connection portion 42b and the connection portion 43b.

[0045] In this embodiment, the front link mechanism 30 and the rear link mechanism 40 are disposed substantially parallel to the front-rear direction. The distance in the left-right direction from the connection portion 33a between the second front link 33 and the bolster 23 to the connection portion 43a between the second rear link 43 and the bolster 23 is equal to the distance in the left-right direction from the connection portion 33b between the second front link 33 and the front lever 31 to the connection portion 43b between the second rear link 43 and the rear lever 41.

[0046] The leverage ratios of the front link mechanism 30 and the rear link mechanism 40 are appropriately set so that the front wheelset 25 and the rear wheelset 26 each face the same direction as the rail 1 on a curved road. The leverage ratios of the front link mechanism 30 and the rear link mechanism 40 may be set according to the wheelbase (the distance in the fore-and-aft direction between the axle 252 and the axle 262) of the railway vehicle 10. For example, the wheelbase of a railway vehicle 10 traveling on a curved road with a curve radius of approximately 100 m is approximately 2000 mm. In this case, the leverage ratios of the front link mechanism 30 and the rear link mechanism 40 are typically 6 or more. The leverage ratio of the front link mechanism 30 refers to the ratio of the dimension of the front lever 31 from the support portion 31a between the bogie frame 21 and the front lever 31 to the connection portion 32b between the first front link 32 and the front lever 31 to the support portion 31a. Similarly, the leverage ratio of the rear link mechanism 40 means the ratio of the dimension of the rear lever 41 from the support portion 41a between the bogie frame 21 and the rear lever 41 to the connection portion 42b between the first rear link 42 and the rear lever 41 to the dimension of the rear lever 41 from the connection portion 43b between the second rear link 43 and the rear lever 41 to the support portion 41a.

[0047] Here, while passing through a curved road, the bogie frame 21 rotates relative to the bolster 23. In the railway vehicle 10 equipped with the bogie 20 according to this embodiment, the coefficient of friction between the bolster 23 and the side bearings 24L, 24R is relatively large, so there may be a bogie angle remaining when entering a straight road from a curved road. In this case, the bogie frame 21, the front wheel set 25, and the rear wheel set 26 tilt relative to the bolster 23 when viewed in the up-down direction.

[0048] Fig. 4 is a top view of the railway vehicle 10. Fig. 4 shows the railway vehicle 10 in a state in which the bogie frame 21, front wheelset 25, and rear wheelset 26 are tilted with respect to the bolster 23 when the railway vehicle 10 enters a straight road from a right-curve road. At this time, a longitudinal creep force acts on each of the front wheelset 25 and rear wheelset 26. In Fig. 4, the longitudinal creep forces acting on the front wheelset 25 and rear wheelset 26 are indicated by arrows.

[0049] As described above, the bogie 20 according to this embodiment includes the front link mechanism 30 and the rear link mechanism 40. As shown in FIG. 4 , when the bogie frame 21, the front wheel set 25, and the rear wheel set 26 are tilted relative to the bolster 23, the front wheel set 25 and the rear wheel set 26 are also tilted relative to the rail 1. The front wheel set 25 is slightly offset to the right of the center of the bogie 20 in the left-right direction, and the rear wheel set 26 is slightly offset to the left of the center of the bogie 20 in the left-right direction. In this case, the right wheel 251R of the front wheel set 25 contacts the rail 1 near the flange, and the left wheel 251L contacts the rail 1 at a position away from the flange. Meanwhile, the left wheel 261L of the rear wheel set 26 contacts the rail 1 near the flange, and the right wheel 261R contacts the rail 1 at a position away from the flange. At this time, the rear wheel set 26 receives a force from the rear link mechanism 40 in a direction that moves it closer to the center in the left-right direction. In other words, the rear link mechanism 40 reduces the vertical creep force acting on the rear wheel set 26. As a result, the rear wheel set 26 is moved to the center in the left-right direction, as shown in Figure 5. At the same time, the inclination of the rear wheel set 26 with respect to the rail 1 is eliminated. Figure 5 is a top view of the railway vehicle 10.

[0050] In the state shown in Fig. 5, the bogie frame 21 is pulled by the rear wheel set 26 and turns in a direction that slightly reduces the inclination with respect to the bolster 23, but the inclination with respect to the bolster 23 still remains. In addition, the front wheel set 25 does not change from the state shown in Fig. 4.

[0051] At the same time that the rear wheelset 26 is moved toward the center in the left-right direction, a vertical creep force acts on the front wheelset 25 in a direction that reduces the bogie angle. This vertical creep force is also applied to the bogie frame 21 via the front link mechanism 30. As a result, the inclination of the front wheelset 25 and the bogie frame 21 relative to the bolster 23 is eliminated, and the bogie 20 returns to the position shown in Figure 1. As described above, the bogie angle can be reduced with the bogie 20 according to this embodiment, and therefore wheel flange wear can be suppressed.

[0052] Furthermore, the bogie angle is reduced using the front link mechanism 30 and the rear link mechanism 40 in the bogie 20 according to this embodiment. The front link mechanism 30 and the rear link mechanism 40 are arranged point-symmetrically with each other. Specifically, the front link mechanism 30 connects the left front axle box 27L to the bolster 23. The rear link mechanism 40 connects the right rear axle box 28R to the bolster 23. In this case, the number of parts is smaller than when each front link mechanism 30 and rear link mechanism 40 connects both the front axle boxes 27L, 27R and the rear axle boxes 28L, 28R to the bolster 23, respectively. Therefore, the bogie 20 according to this embodiment can suppress flange wear of the wheels 251L, 251R, 261L, 261R with a simple configuration.

[0053] The above describes the embodiments of the present disclosure. However, the above-described embodiments are merely examples for implementing the present disclosure. Therefore, the present disclosure is not limited to the above-described embodiments, and the above-described embodiments can be modified as appropriate within the scope of the present disclosure. For example, the bogie 20 may be configured such that the front link mechanism 30 connects the right front axle box 27R and the bolster 23, and the rear link mechanism 40 connects the left rear axle box 28L and the bolster 23.

[0054] In the above embodiment, the front link mechanism 30 is connected near the left end of the bolster 23, and the rear link mechanism 40 is connected near the right end of the bolster 23. However, the connection positions of the front link mechanism 30 and the rear link mechanism 40 to the bolster 23 are not limited to this. The front link mechanism 30 and the rear link mechanism 40 may be connected to the bolster 23 at a position closer to the center of the bogie 20 in the left-right direction. In this case, the front lever 31 and the rear lever 41 can be made shorter than when the front link mechanism 30 and the rear link mechanism 40 are connected to the ends of the bolster 23, respectively, and therefore the front link mechanism 30 and the rear link mechanism 40 can be made smaller.

[0055] In the above embodiment, the front link mechanism 30 and the rear link mechanism 40 are disposed substantially parallel to the front-rear direction. However, the front link mechanism 30 and the rear link mechanism 40 may be entirely tilted relative to the front-rear direction in a top view. FIG. 6 is a top view schematically showing a railway vehicle 10 including a bogie 20 according to a modified example. In the example shown in FIG. 6, the front link mechanism 30 is disposed such that its front portion is positioned outward in the left-right direction relative to its rear portion. The rear link mechanism 40 is disposed such that its front portion is positioned inward in the left-right direction relative to its rear portion. In this case, the distance L1 in the left-right direction from the connection portion 33a between the second front link 33 and the bolster 23 to the connection portion 43a between the second rear link 43 and the bolster 23 is shorter than the distance L2 in the left-right direction from the connection portion 33b between the second front link 33 and the front lever 31 to the connection portion 43b between the second rear link 43 and the rear lever 41. Furthermore, a distance L3 in the left-right direction from the connection portion 32a between the first front link 32 and the front axle box 27L to the connection portion 42a between the first rear link 42 and the rear axle box 28R is greater than the distance L2.

[0056] When the distance L1 is smaller than the distance L2, the connection portion 33a between the second front link 33 and the bolster 23 and the connection portion 43a between the second rear link 43 and the bolster 23 are positioned on the inner side in the left-right direction. Therefore, when traveling along a curved road, the displacement of the connection portion 33a and the connection portion 43a in the front-rear direction is relatively small. On the other hand, when the distance L3 is larger than the distance L2, the connection portion 32a between the first front link 32 and the front axle box 27L and the connection portion 42a between the first rear link 42 and the rear axle box 28R are positioned on the outer side in the left-right direction. Therefore, the displacement of the connection portion 32a and the connection portion 42a in the front-rear direction is relatively large when traveling along a curved road. As a result, according to the railway vehicle 10 of FIG. 6, the leverage ratio of the front link mechanism 30 and the rear link mechanism 40 can be reduced. If the leverage ratio of the front link mechanism 30 and the rear link mechanism 40 is small, excessive rotation of the bolster 23 can be suppressed. The leverage ratio of each of the front link mechanism 30 and the rear link mechanism 40 may be less than six.

[0057] The front link mechanism 30 and the rear link mechanism 40 may have portions inclined relative to the front-rear direction in a top view. FIGS. 7 and 8 are top views schematically showing a railway vehicle 10 equipped with a bogie 20 according to a modified example. In the example shown in FIG. 7 , the portion of the front link mechanism 30 from the front lever 31 to the bolster 23 (second front link 33) is inclined relative to the front-rear direction, while the portion from the front axle box 27L to the front lever 31 (first front link 32) is substantially parallel to the front-rear direction. The second front link 33 is disposed such that its front portion is positioned outward in the left-right direction relative to its rear portion. The portion of the rear link mechanism 40 from the bolster 23 to the rear lever 41 (second rear link 43) is inclined relative to the front-rear direction, while the portion from the rear lever 41 to the rear axle box 28R (first rear link 42) is substantially parallel to the front-rear direction. The second rear link 43 is disposed such that its front portion is positioned more inward in the left-right direction than its rear portion.

[0058] In the example shown in Fig. 7, similar to the example shown in Fig. 6, distance L1 is smaller than distance L2. When traveling along a curved road, displacement in the fore-and-aft direction at connection portions 33a and 43a is relatively small. Therefore, according to the railway vehicle 10 of Fig. 7, the leverage ratio of the front link mechanism 30 and the rear link mechanism 40 can be reduced. Note that in the railway vehicle 10 of Fig. 7, distance L3 (Fig. 6) is equal to distance L2.

[0059] In the example shown in FIG. 8 , the portion of the front link mechanism 30 from the front axle box 27L to the front lever 31 (first front link 32) is inclined with respect to the front-to-rear direction, while the portion from the front lever 31 to the bolster 23 (second front link 33) is substantially parallel with respect to the front-to-rear direction. The first front link 32 is disposed so that its front portion is positioned outward in the left-to-right direction from its rear portion. The portion of the rear link mechanism 40 from the rear lever 41 to the rear axle box 28R (first rear link 42) is inclined with respect to the front-to-rear direction, while the portion from the bolster 23 to the rear lever 41 (second rear link 43) is substantially parallel with respect to the front-to-rear direction. The first rear link 42 is disposed so that its front portion is positioned inward in the left-to-right direction from its rear portion.

[0060] In the example shown in Fig. 8, similar to the example shown in Fig. 6, distance L3 is greater than distance L2. When traveling along a curved road, displacement in the fore-and-aft direction at connection portions 32a and 42a becomes relatively large. Therefore, according to the railway vehicle 10 of Fig. 8, the leverage ratio of the front link mechanism 30 and the rear link mechanism 40 can be reduced. Note that in the railway vehicle 10 of Fig. 8, distance L1 (Fig. 6) is equal to distance L2.

[0061] The leverage ratios of the front link mechanism 30 and the rear link mechanism 40 can be reduced by adjusting the positions of the connection portion 33b between the second front link 33 and the front lever 31 and the connection portion 43b between the second rear link 43 and the rear lever 41. Specifically, the leverage ratio of the front link mechanism 30 can be reduced by moving the position of the connection portion 33b between the second front link 33 and the front lever 31 closer to the support portion 31a between the bogie frame 21 and the front lever 31. Furthermore, the leverage ratio of the rear link mechanism 40 can be reduced by moving the position of the connection portion 43b between the second rear link 43 and the rear lever 41 closer to the support portion 41a between the bogie frame 21 and the rear lever 41. Therefore, the front lever 31 and the rear lever 41 can be shortened. As another method for reducing the leverage ratio of the front link mechanism 30 and the rear link mechanism 40, it is possible to move the position of the connection portion 32b between the first front link 32 and the front lever 31 away from the support portion 31a, and also to move the position of the connection portion 42b between the first rear link 42 and the rear lever 41 away from the support portion 41a. However, in this case, the front lever 31 and the rear lever 41 cannot be shortened. [Explanation of symbols]

[0062] 10: Railway vehicles 20: Cart 21: Bogie frame 23: Bolster 24L, 24R: Side support 25: Front wheel axle 26: Rear wheel axle 27L, 27R: Front axle box 28L, 28R: Rear axle box 30: Front link mechanism 31: Front lever 32: First previous link 33: Second previous link 40: Rear link mechanism 41: Rear lever 42: First link 43: Second link

Claims

1. A bogie for a railway vehicle, The bogie frame and a bolster extending in the left-right direction of the bogie; two side supports that are disposed on the bogie frame at an interval in the left-right direction and support the bolster; a front wheel set provided on the front side of the bogie frame with respect to the bolster; a rear wheel axle provided on the rear side of the bogie frame with respect to the bolster; two front axle boxes respectively disposed at the left and right ends of the front wheelset; two rear axle boxes respectively disposed at the left and right ends of the rear wheel axle; a front link mechanism connecting one of the two front axle boxes to the bolster; a rear link mechanism that connects the rear axle box, one of the two rear axle boxes, located on the opposite side of the front link mechanism in the left-right direction, to the bolster, the front link mechanism includes a front lever rotatably supported on the bogie frame, a first front link connecting the front axle box and the front lever, and a second front link connecting the bolster and the front lever, a connection portion between the first front link and the front lever is located on an opposite side to a connection portion between the second front link and the front lever with respect to a support portion between the bogie frame and the front lever in the vertical direction of the railway vehicle, the rear link mechanism includes a rear lever rotatably supported on the bogie frame, a first rear link connecting the rear axle box and the rear lever, and a second rear link connecting the bolster and the rear lever, a connection portion between the first rear link and the rear lever is located on the same side as a connection portion between the second rear link and the rear lever with respect to a support portion between the bogie frame and the rear lever in the vertical direction.

2. The bogie according to claim 1, a distance in the left-right direction from a connection portion between the second front link and the bolster to a connection portion between the second rear link and the bolster is shorter than a distance in the left-right direction from the connection portion between the second front link and the front lever to the connection portion between the second rear link and the rear lever.

3. The bogie according to claim 1, a bogie in which the distance in the left-right direction from the connection portion between the first front link and the front axle box to the connection portion between the first rear link and the rear axle box is greater than the distance in the left-right direction from the connection portion between the second front link and the front lever to the connection portion between the second rear link and the rear lever.

4. A bogie according to any one of claims 1 to 3, The bogie, wherein the front link mechanism and the rear link mechanism each have a leverage ratio of less than 6.

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