GB2530677A

GB2530677A - Railroad vehicle capable of reducing lateral force and lateral force reduction method

Info

Publication number: GB2530677A
Application number: GB1520260.9A
Authority: GB
Inventors: Ryu Narikawa; Katuyuki Iwasaki; Takao Watanabe; Takashi Takahira; Kenjirou Gouda; Masataka Hidai
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2013-06-07
Filing date: 2013-06-07
Publication date: 2016-03-30
Anticipated expiration: 2033-06-07
Also published as: DE112013007135B4; GB2530677B; GB201520260D0; JPWO2014196080A1; DE112013007135T5; JP6067850B2; WO2014196080A1

Abstract

When a railroad vehicle passes a curve, switching between longitudinal rigidities (rigidities with respect to displacement in a longitudinal direction) of air springs (6a, 6b) is performed according to the direction of travel. With regard to the air spring (6a) in which the direction of a reaction moment acting on a truck acts on a direction (C) in which the turning of the truck is impeded, the longitudinal rigidity is relatively decreased, and with regard to the air spring (6b) in which the direction of the reaction moment acting on the truck acts on a direction (J) in which the turning of a vehicle body is accelerated, the longitudinal rigidity is relatively increased. By merely adding a mechanism for switching between the longitudinal rigidities of the air spring (6a, 6b) according to the direction of travel as described above, the influence of lateral force (H, G) on a track is minimized without causing a large cost increase and an increase in unsprung mass.

Description

[DESCRIPTION]

[Title of Invention]

RAILWAY VEHICLE CAPABLE OF REDUCING LATERAL FORCE AND

LATERAL FORCE REDUCTION METHOD

[Technical Field]

[0001] The present invention relates to a railway vehicle having a mechanism that can reduce a lateral force generated between a truck supporting the railway vehicle and a track, when passing through a curve.

[Background Art]

[0002] A typical railway vehicle truck is made up of a wheelset having wheels at both ends of an axle, an axle box unit rotatably holding the wheelset, and a truck frame forming a framework of the truck. The axle box unit is elastically supported in longitudinal, lateral, and vertical directions with respect to the truck frame by an axle box support device. Also, an air spring is provided between a top surface of the truck frame and a bottom surface of a vehicle body. By this air spring, the vehicle body is elastically supported in each of longitudinal, lateral, and vertical directions with respect to the truck.

[0003] Since the support rigidity in the longitudinal direction of the axle box unit by the axle box support device is relatively high, when the railway vehicle passes through a curve, the wheelset cannot sufficiently follow the curve and a lateral force that is a force with which the wheels is pushed toward sleepers by rails tends to be generated. This lateral force accelerates wear of the wheels and rails and causes noises due to squeals between the wheels and rails. Therefore, how this can be reduced is an important problem.

[0004] PTL I discloses a railway vehicle truck that can reduce lateral forces when passing through a curve. The abstract of PTL 1 includes the description that "the steering device 6 of the railway vehicle truck is to rotate, symmetrically about the truck, two front and rear wheel axles 3 provided to be rotatable by a certain angle to a truck frame 2. This device 6 grasps a relative rotation angle (a,) of the truck frame 2 to the vehicle body 1 and provides a relative rotation angle (j3,) of the wheel axles 3 to the truck frame 2. The steering device 6 is configured to operate so as to apply a rotation increased by 20 to 35% of the theoretical relative rotation angle, to the wheel axles. Also, since the link mechanism of the steering device 6 is horizontally arranged, an equal steering operation is applied to the front and rear wheel axles of the truck." [Citation List] [Patent Literature] [0005] [PTL 1] JP-A-1O-203364 [Suimuary of Invention] [Technical Problem] [0006] The railway vehicle truck disclosed in PTL 1 includes: a steering beam which has a rotation axis concentric with the center of rotation of the truck frame and performs a rotary motion similar to the vehicle body on a curved track; a pair of horizontal levers on the left and right of the truck frame, each having the center of rotation near the middle in the longitudinal direction of side beams on the left and right of the truck frame; a link coupling the steering beam and the horizontal levers; and a coupflng rod which couples a point at an equal distance to the left and right from the centers of rotation of the horizontal levers, with front and rear axle box units on the same side of the left and right of the truck device.

[0007] This railway vehicle truck forms a so-called steering truck which steers the wheelset by grasping a relative rotation angle of the truck to the vehicle body, and therefore employs a complex structure. This causes a rise in cost, fall in durability, and fall in reliability. Moreover, in a transition curve section which connects a straight line and a circular curve, there is a possibility of failure to perform sufficient steering and hence decrease in the lateral force reduction effect, due to a delay in the rotary operation of the steering beam or a lack of &n angle of turning of the truck necessary for steering.

Also, since the coupling rod is directly connected to the axle box, the problem of increase in the unsprung mass and increase in its influence on the track arises.

[0008] Thus, an object of the invention is to provide a railway vehicle and a lateral reduction method which can restrain wear of wheels and rails and also reduce noises such as squeals between these by reducing lateral forces without increasing the unsprung mass that can increase track maintenance costs or using a complex device (configuration) that can be a factor in raising maintenance costs.

[Solution to Problem] [0009] To achieve the above object, a railway vehicle according to the invention includes: a vehicle body which passengers get on; a truck having an air spring elastically supporting the vehicle body; an air spring displacement suppression device which controls rigidity in a longitudinal direction of the air spring; and a control device which detects a direction of travel of the railway vehicle made up of the vehicle body and the truck and controls the air spring displacement suppression device.

Also, a lateral force reduction method for a railway vehicle according to the invention includes: detecting a direction of travel of a vehicle; and controlling longitudinal rigidity of an air spring provided in a truck which supports the vehicle.

[Advantageous Effect of Invention] [0010] With the above configurations, a railway vehicle and a lateral reduction method for a railway vehicle which can restrain wear of wheels and rails and also reduce noises such as squeals between these by reducing lateral forces without increasing the unsprung mass and without using a complex device (configuration) that can be a factor in raising maintenance costs, can be provided.

Objects, configurations, and effects other than the above will be clarified by the description of embodiments below.

[Brief Description of Drawings]

[0011] [FIG. 1] FIG. 1 is a plan view of a railway vehicle according to Example 1.

[FIG. 2] FIG. 2 is a cross-sectional view showing the state of an air spring in a front truck when passing through a curve in Example 1.

[FIG. 3] FIG. 3 is a cross-sectional view showing the state of an air spring in a rear truck when passing through a curve in Example 1.

[FIG. 4] FIG. 4 is a view showing the moment based on a reaction force of an air spring generated between a vehicle body and a truck when passing through a curve.

[FIG. 5] FIG. 5 is a view showing the details and balance of a steering moment and a resistance moment acting on a truck when passing through a curve.

[FIG. 6] FIG. 6 is a view showing the lateral force reduction effect according to Example 1.

[FIG. 7] FIG. 7 is a cross-sectional view showing the state of an air spring in a front truck when passing through a curve, according to a modification which modifies the support structure of the cover plate in Example 1.

[FIG. 8] FIG. 8 is a cross-sectional view showing the state of an air spring in a rear truck when passing through a curve, according to a modification which modifies the support structure of the cover plate in Example 1.

[FIG. 9] FIG. 9 is a plan view of a railway vehicle truck according to Example 2.

[FIG. 10] FIG. 10 is a cross-sectional view showing the state and structure of an air spring in a front truck when passing through a curve in Example 2.

[FIG. 11] FIG. 11 is a cross-sectional view showing the state and structure of an air spring in a front truck when passing through a curve in Example 2.

[FIG. 12] FIG. 12 is a plan view of a railway vehicle truck according to Example 3.

[FIG. 131 FIG. 13 is a plan view of the case where Example 2 of the invention is applied to articulated vehicles by a two-point air spring support system according to Example 4.

[FIG. 14] FIG. 1415 a view showing the details andbalance of a steering moment and a resistance moment acting on trucks when the articulated vehicles by the two-point air spring support system according to Example 4 pass through a curve.

[FIG. 15] FIG. 15 is a plan view of the case where Example 2 of the invention is applied to articulated vehicles by a four-point air spring support system according to Example 5.

[FIG. 16] FIG. 16 is a view showing the balance of a steering moment and a resistance moment acting on trucks when the articulated vehicles by the four-point air spring support system according to Example 5 pass through a curve.

[FIG. 17] FIG. 17 is a side view of an ordinary railway vehicle.

[Description of Embodiments]

[0012] Hereinafter, examples of the invention will be described using the drawings.

[Examples]

[0013]

[Example 1]

Example 1 of the invention will be described.

FIG. 17 shows a side view of a typical railway vehicle.

A railway vehicle 1 includes a vehicle body 1 loaded with passengers and freight, and a truck 2 supporting this vehicle body 1. The truck 2 includes a truck frame 3 forming the framework thereof, a wheelset 5 having wheels at both ends of an axle, an axle box unit 4 rotatably holding the wheelset 5, an air spring 6 provided on a top surface of the truck frame 3, and the like.

[0014] The axle box unit 4 is elastically supported in each of longitudinal, lateral (sleeper), and vertical directions with respect to the truck frame 3 by an axle box support device.

The vehicle body 1 is elastically support in each of longitudinal, lateral (sleeper), and vertical directions by the air spring 6 provided in the truck 2.

In a middle part of the truck frame 3, a site (not shown) where a center pin (not shown) extending downward front the bottom surface of the vehicle body is inserted is provided.

When the railway vehicle travels through a curve or the like, the truck 2 turns around this center pin substantially within a horizontal plane.

[0015] FIG. 1 is a plan view schematically showing the railway vehicle according this example. The vehicle body 1 is supported by a front truck 2a via an air spring 6a and by a rear truck 2b via an air spring 6b. As described below using FIG. 2 and FIG. 3, air spring displacement suppression devices 95a, 95b are provided ahead of and behind the air springs 6a, 6b, respectively, and switching between respective actuators 81a, 81b is performed according to the direction of travel of the railway vehicle, by a control device 7 shown in FIG. 1.

The control device 7 may be provided under the floor of the vehicle body 1 or may be provided in an in-vehicle equipment room in the vehicle body 1.

[0016] Since the air spring displacement suppression devices 95a, 95b have substantially the same configuration, the configuration of the air spring displacement suppression device 95a will be described using FIG. 2.

The devices are provided ahead of and behind the air spring 6a (in a direction along the longitudinal direction of the vehicle body 1) in the form of facing each other from both sides of the air spring. The air spring displacement suppression device includes a cover plate 84a which suppresses deformation of a diaphragm 63 forming the air spring 6, and the actuator 81a which controls the space (gap) between the cover plate 84a and the diaphragm 63a.

[0017] In FIG. 1, when the direction of travel of the railway vehicle is an arrow E, the truck 2a is the front truck and the truck 2b is the rear truck. Meanwhile, when the direction of travel is an arrow F, the truck 2a is the rear truck and the truck 2b is the front truck. In the examples below including this example, only the one direction of travel in the case of the arrow E will be described since similar advantageous effects can be achieved regardLess of the direction of travel of the railway vehicle.

[0018] FIG. 2 and FIG. 3 are cross-sectional views showing the structures around the air springs according to this example.

When the direction of travel of the railway vehicle is indicated by the arrow E or the arrow F and the railway vehicle passes through a curve, FIG. 2 shows the operation state of the air spring displacement suppression device 95a of the front truck 2a and FIG. 3 shows the operation state of the air spring displacement suppression device 95b of the rear truck 2b.

[0019] In FIG. 2, the air spring 6a includes a top plate 61a, a bottom plate 62a, the diaphragm 63a connecting the top plate 61a and the bottom plate 62a, and a multilayer rubber 66a made up of metal plates 64a and rubbers 65a, arranged below the bottom plate 62a, or the like. The metal plates 64a and the rubbers 65a are annular plate members having an opening at the center. These are alternately stacked, thus forming the cylindrical multilayer rubber 66a having an opening at the center. The inside of the diaphragm 63a is filled with high-pressure air. Also, near the air spring 6a on the bottom surface of the vehicle body 1, a set of the air spring displacement suppression devices 95a capable of expanding and contracting in the longitudinal direction of the vehicle body is provided in the form of facing each other from both sides of the air spring 6a along the longitudinal direction of the vehicle body 1.

[0020] The air spring displacement suppression device 95a mainly includes the cover plate 84a which suppresses displacement of the diaphragm 63a forming the air spring, and the actuator 81a which is connected to this cover plate 84a and controls the space (gap) between the cover plate 84a and the diaphragm 63a. The cover plate 84a includes a coittact part 82a made up of a member with a low coefficient of friction that is brought in contact with the diaphragm 63a, and a support part 83a supporting the contact part 82a and connected to the actuator 81a.

[0021] As the actuator 8la expands or contracts on the basis 1].

of a command from the control device 7 shown in FIG. 1, the distance (gap) between the contact part 82a of the cover plate 84a and the diaphragm 63a can be controlled. The arrangement forms and structures of the air spring, the actuator and the like, and the actuation based on the command from the control device 7 are similarly applied to the rear truck 2b shown in FIG. 3.

[0022] In the state where the actuator 81b is made to expand and the contact part 82b is brought closely to the diaphragm 63b, as shown in FIG. 3, if the truck 2a turns and the air spring 6b is longitudinally displaced, the lateral surface of the deformed diaphragm 63b contacts (comes into contact with) the contact part 82b. With this, since the displacement of the diaphragm 63b is suppressed and the air reaction force of the diaphragm 63b increases, rigidity against the longitudinal displacement of the air spring 6b (hereinafter referred to as longitudinal rigidity) is increased.

[0023] FIG. 4 shows a schematic illustration of the moment due to the air spring reaction force acting on the truck 2 when passing through a curve. When the railway vehicle travels in the direction of the arrow E, the truck 2a is the front truck and the truck 2b is the rear truck.

When the railway vehicle travels from a straight line to a curve, the trucks turn following the curvature of the curve and therefore have a relative rotation angle to the vehicle body 1. Consequently, top ends (top plates 61a, 61b) of the air springs 6a, 6b situated on the left and right of the trucks 2 in the state of being turned with respect to the vehicle body 1 follow the vehicle body 1, and the bottom ends (bottom plates 62a, 62b and multilayer rubbers 66a, 66b) of the air springs 6a, Cb follow the trucks 2. Therefore, the air springs 6a, 6b are deformed in the longitudinal direction (direction of an arrow 100). Since the air springs 6a, 6b deformed in the longitudinal direction are trying to restore their original shapes, an air spring reaction force is generated from the vehicle body I to the trucks 2.

The reaction force of the air spring 6a generated in the front truck 2a that is passing through the curve is in the directions indicated by arrows A, A' for the left and right, respectively. Similarly, the reaction force of the air spring 6b generated in the rear truck 2b is as indicated by arrows B, B' for the left and right, respectively.

[0024] These air spring reaction forces A (A'), B (B') generate a moment which acts to turn the front truck 2a or the rear truck 2b, or a resistance moment in the reverse direction of the direction of turning.

That is, a moment C due to the air spring 6a generated in the front truck 2a is a counterclockwise moment in FIG. 4, and a moment D due to the air spring 6b generated in the rear truck 2b is a clockwise moment in FIG. 4.

[0025] At this time, the moment C acting on the front truck 2a is in the direction opposite to (reverse direction of) the direction of turning of the front truck 2a when traveling from a straight line to a curve and therefore acts as a resistance moment which prevents the turning of the front truck 2a.

Meanwhile, the moment D acting on the rear truck 2b is in the same direction as the direction of turning of the rear truck 2b when the railway vehicle travels from a straight line to a curve, and therefore acts as a steering moment which accelerates the turning of the rear truck 2b.

[0026] FIG. 5 shows the details and balance of moments acting on each truck when passing through a curve.

The steering moment generated in the front truck 2a includes a moment K due to a lateral force H, and a moment a due to other factors such as a longitudinal creep force. Also, the resistance moment generated in the front truck 2a includes a moment C due to air spring reaction forces A, A', and moment J3 due to other factors such as a longitudinal creep force.

Meanwhile, the steering moment generated in the rear truck 2b includes a moment J due to a lateral force G, a moment D due to air spring reaction forces B, B', and a moment y due to other factors such as a longitudinal creep force. Also, the resistance moment generated in the rear truck 2b is a moment 8 due to other factors such as a longitudinal creep force.

[0027] When the railway vehicle passes through a curve, each truck is maintained in a state (posture) having a relative rotation (turn) angle to the vehicle body. Therefore, the state where the steering moment, which is the sum of the respective moments in the direction of steering (turning), and the resistance moment, which is the sum of the respective moments in the reverse direction of the direction of turning, are balanced is maintained in each truck.

In short, in a stationary state when passing through a curve, in the front truck 2a, the steering moment (moment in the direction of steering), which is the sum of the moment cc and the moment K, and the resistance moment (moment in the reverse direction of the direction of steering), which is the sum of the moment J3 and the moment C, become balanced.

[0028] Similarly, in the rear truck 2b, the steering moment, which is the sum of the moment 3, the moment D and the moment y, and the moment 6, which is the resistance moment, become balanced. Such a balanced relationship between the sum of the respective moments forming the steering moment and the sum of the respective moments forming the resistance moment in each truck while passing through a curve, is common to the examples below.

[0029] Here, in the front truck 2a, the moment K due to the lateral force H, and the moment C due to the air spring reaction forces A, A' are in the opposite (reverse) directions to each other. Therefore, since the balanced state between the steering moment and the resistance moment acting on the front truck 2a is maintained, if the moment C, which is the resistance moment, is reduced, the moment K, which is the steering moment due to the lateral force H, is reduced. That is, if the moment K is reduced, the lateral force H causing the moment K can be consequently reduced in itself.

[0030] Meanwhile, in the rear truck 2b, the moment J due to the lateral force G and the moment D due to the air spring reaction forces B, B' are in the same direction. Also in the rear truck 2b, since the balanced state between the steering moment and the resistance moment is maintained, if the moment D, which is the steering moment, is increased, the moment J, which is the steering moment due to the lateral force G, is reduced and the lateral force G on the rear truck 2b can be consequently reduced.

In short, in the front truck 2a, the lateral force H can be reduced by decreasing the longitudinal rigidity of the air spring 6a, and in the rear truck 2b, the lateral force G can be reduced by increasing the longitudinal rigidity of the air spring 6b.

[0031] Thus, in this example, when passing through a curve, the longitudinal rigidity of the air spring 6a in the front truck 2a is set to be an allowable minimum value, thereby decreasing the moment C acting on the front truck 2a and thus reducing the lateral force H. At the same time, the longitudinal rigidity of the air spring 6b in the rear truck 2b is increased and the moment D acting on the rear truck 2b is thus increased, thereby reducing the lateral force G. [0032] Referring to FIG. 2 and FIG. 3, the mechanism (actions) by which the truck provided in the railway vehicle in Example 1 reduces the lateral force will be described.

If the direction of travel of the railway vehicle is the direction of the arrow E in FIG. 1, the control device 7 detects the direction of travel of the railway vehicle and outputs a command signal for contraction, to the actuator 81a forming the air spring displacement suppression device 95a in the front truck 2a supporting the vehicle body 1, and a command signal for expansion, to the actuator 81b of the air spring displacement suppression device 95b in the rear truck 2b.

[0033] In this example, in both of the front truck 2a and the rear truck 2b, an initial value of the longitudinal rigidity of the air springs 6a, 6b (longitudinal rigidity in the case where the diaphragms 63a, 63b and the contact parts 82a, 92b are not in contact with each other in the air springs 6a, 6b) is set to a minimum value within a range that does not impair comfortable ride quality even at the time of traveling through a curve. Therefore, when a contraction command is sent from the control device 7 to the actuator 81a and the cover plate 84a is separated away from the diaphragm 63a, the longitudinal rigidity of the air spring 6a has this initial value.

[0034] Meanwhile, when an expansion command is sent from the control device 7 to the actuator 81b, the cover plate 84b expands toward and approaches the diaphragm 63b and the air spring 6b is thus displaced in the longitudinal direction.

Then, the lateral side of the diaphragm 63b comes in contact with the cover plate 84b, and the deformation of the diaphragm 63b is suppressed, increasing the air reaction force.

Therefore, the longitudinal rigidity of the air spring 6 is increased.

[0035] Thus, in the front truck 2a, the longitudinal rigidity of the air spring 6a has the initial value, and the moment C due to the air spring reaction forces A, A' forming the resistance moment is reduced ott the basis of the relation between the steering moment and the resistance moment shown in FIG. 5. Therefore, the steering moment K due to the lateral force H forming the steering moment is reduced accordingly.

Meanwhile, also in the rear truck 2b, since the balanced state between the steering moment and the resistance moment is maintained, increasing the longitudinal rigidity of the air spring 6b and increasing the moment D due to the air spring reaction forces B, B' forming the steering moment consequently reduces the moment J due to the lateral force G, which is the steering moment, and the lateral force G on the rear truck 2b can be reduced.

[0036] In this example, the control device 7 sends, for example, a contraction command to the actuator 81a on the side of the front truck and an expansion command to the actuator 81b on the side of the rear truck every time the direction of travel is switched at a turn-back station as a start point, and the control device 7 holds this state until reaching a turn-back station as a terminal point. Therefore, given the contraction and expansion of the actuators Bla, 8lb, providing a lock device for holding the contraction and expansion of each actuator enables reduction in power consumption required for the actuation of the actuators.

[0037] The direction of travel of the railway vehicle may be detected by the control device 7, not only at the start of turn-back running but also via an in-vehicle speed detector, signals received from a ground device, and the GPS or the like.

The actuators as the air spring displacement suppression devices may be controlled in the direction of reducing the lateral force generated at the time of passing through a curve in the direction of travel, and the longitudinal rigidities of the air springs elastically 5upporting the vehicle body may be adjusted to an optimum value.

[0038] Moreover, if none of the contraction and expansion command signals is outputted because of a failure or the like in the control device 7, this lock device fixes the actuators 8].a, 81b at an intermediate position between the contraction position taken when the actuator is not actuated and the expansion position taken when the actuator is actuated.

[0039] Thus, even if the air springs 6a, 6b are displaced in the longitudinal direction when traveling through a curve or the like, the force with which the cover plates 84a, 84b suppress the deformation of the diaphragms 63a, 63b is relaxed compared with when the actuators are at the expansion position.

Therefore, the longitudinal rigidities of the air springs 6a, 6b when the respective actuators 81a, 8Th are fixed at the internuediate position are set to a general value greater than the foregoing minimum value, so as not to impede the running performance.

[0040] In this way, in the air spring 6a of the front truck 2a, the actuator 81a contracts and the distance between the cover plate 84a and the diaphragm 63a expands. Therefore, even if the air spring 6a is longitudinally displaced when passing through a curve, the diaphragm 63a and the cover plate 84a do not come into contact with (contact) each other, and the longitudinal rigidity of the air spring 6a has the foregoing initial value. Thus, the moment C which prevents the turning (see FIG. 4) does not increase.

[0041] In contrast, in the air spring 6b of the rear truck 2b, the actuator 81b expands and the distance (gap) between the cover plate 84b and the diaphragm 63b decreases. Therefore, with the longitudinal displacement of the air spring, the lateral side of the diaphragm 63b contacts the contact part 83b and the deformation of the diaphragm 63b is suppressed, increasing the air reaction force. Thus, the moment D which accelerates the turning (see FIG. 4) is increased.

Since the lateral force H on the front truck 2a and the lateral force G on the rear truck 2b are effectively reduced by the above actions, the wear of the rails and wheels can be suppressed and squeals between these can be reduced.

10042] The contact parts 82a, 82b attached to the cover plates 84a, 84b are formed of a material with a low coefficient of friction such as a self-lubricating resin and therefore can suppress the wear of the diaphragms 63a, 63b. Moreover, if the shape of the contact parts 82a, 82b is adjusted to the outer shape (doughnut-shaped curve surface) of the diaphragms 63a, 63b, the wear of the diaphragms 63a, 63b can be suppressed further.

By the above method for suppressing the wear of the diaphragms 63a, 63b, reduction in the life (replacement cycle) of the diaphragms 63a, 63b can be restrained against the operation of increasing the longitudinal rigidities of the air springs with the actuators 81a, 81b.

[0043] The operations when the direction of travel of the railway vehicle is the arrow E are described above. When the direction of travel is the arrow F in FIG. 1. and the truck 2a is the rear truck while the truck 2b is the front truck, the actuators 81 perform the opposite (reverse) operations and the control device 7 outputs commands to cause the actuator 81a to expand and the actuator 81b to contract.

[0044] FIG. 6 shows an example of the lateral force reduction effect according to this example. In FIG. 6, the horizontal axis represents kilometrage Cm), where transition curves are set before and after a circular curve. The vertical axis represents horizontal force (1Q4). As clear from this illustration, the lateral force can be reduced both on the transition curves and the circular curve, compared with an ordinary truck.

[0045] In the configurations shown in FIG. 2 and FIG. 3, the cover plates 84 perform translational movement in the longitudinal direction of the vehicle, due to the expansion and contraction of the actuators 81a, 81b. However, using a configuration in which, with a shaft 85a arranged at the top end of the cover plate 84a in a direction along the direction of sleepers, and a bracket 86a having the shaft 85a and fixed to the bottom surface of the vehicle body 1, and with the expansion and contraction of the actuator 81a installed on the bottom surface of the vehicle body, the cover plate 84a rotates around the shaft 85a so as to enable change in the distance between the diaphragm 63a and the cover plate 84a, as shown in FIG. 7, effects similar to the configuration shown in FIG. 2 and FIG. 3 can be achieved.

[0046] FIG. 7 shows the state where, at the time of passing through a curve in the case where the direction of travel of the railway vehicle is the arrow E (see FIG. 4), the actuator 8].a contracts on the side of the front truck 2b and where the cover plate 84a is rotated in the direction in which the contact part 82a of the cover plate 84a moves away from the diaphragm 63a.

Meanwhile, FIG. 8 shows the state where the actuator 81b expands on the side of the rear truck 2b and where the cover plate 84b is rotated in the direction in which the contact part 82b of the cover plate 84b approaches and faces the diaphragm 63b, in contrast to the side of the front truck 2b.

[0047] In this way, the top ends of the cover plates 84a, 84b are coupled to the brackets 86a, 86b rotatably by the shafts 85a, 85b, and the distal ends of the actuators 81a, 8Th are rotatably coupled to the bottom ends of the cover plates 84a, 84b. Therefore, the cover plates 84a, 84b can be securely positioned at optimum positions, even by the small actuators 81a, 81b with small outputs. Thus, the degree of freedom in design around the air springs 6a, 6b can be increased and the power consumption required for the actuation of the actuators 81a, 81b can be reduced. Moreover, lighter weight can be facilitated.

[0048]

[Example 2]

Next, Example 2 of the invention will be described. FIG. 9 is a plan view schematically showing a railway vehicle according to this example. As shown in FIG. 10 and FIG. 1]., this railway vehicle has air spring displacement suppression devices 95a, 95b made up of a control device 7 and actuators 81a, 81b. The air spring displacement suppression devices 95a, 95b shown in FIG. 10 and FIG. 11 are different from those in Example 1, and one device each is provided for each air spring 6a, 6b, thus enabling change in the longitudinal rigidity.

[0049] FIG. 10 shows the state of the air spring displacement suppression device 95a provided in the front truck 2a when passing through a curve in the case where the direction of travel of the railway vehicle is the arrowE (see FIG. 9). FIG. 11 shows the state of the air spring displacement suppression device 95b provided in the rear truck 2b, corresponding to FIG. 10.

The air spring displacement suppression device 95a includes an actuator 81a capable of expanding and contracting in the vertical direction, provided in a center space of a cylindrical multilayer rubber 66a inside the air spring 6a, and a stopper cover plate 88a provided on a bottom plate 62a in a top part of the multilayer rubber 66a forming the air spring 6a.

[0050] The actuator 81a provided in the space provided in a center part of the multilayer rubber 66a has an inner stopper 87aat its distal end. The stopper cover plate 88ais a circular plate-like member having a space in its center part. When the actuator 81a is extended in the vertical direction, the inner stopper 87a is fitted in the center part of the stopper cover plate 88a and the displacement of the multilayer rubber 66a is suppressed.

[0051] The inner stopper 87a has an outer peripheral surface in a stepped shape having a section with a smaller outer diameter coaxially on a section with a larger outer diameter.

The section with a smaller outer diameter is fitted in the space in the center part of the stopper cover plate 88a. The space in the center part of the stopper cover plate 88a in which the inner stopper 87a is fitted may be an opening broadening toward the bottom with its inner diameter increasing toward the bottom, and the outer diameter on the bottom side of this opening may be set to be greater than the outer diameter of the inner stopper 87a so that the inner stopper 87a can be fitted securely therein.

When the actuator 81a is retreating (contracting) downward, the smaller-diameter section of the inner stopper 87a does not engage (interfere) with the stopper cover plate 88a, and the multilayer rubber 66a is displaceable in the longitudinal direction.

[0052] Meanwhile, FIG. 11 shows the state on the side of the rear truck 2b. Although the air spring displacement suppression device 95b employs a configuration similar to the air spring displacement suppression device 95a, the state where the inner stopper 87b is held in the form of being extended upward and entering into the stopper cover plate 88b, by the actuator 81b, and where the displacement of the air spring 6 in the longitudinal direction is suppressed, is shown.

The actuators 81a, 81b used in this example are formed cylindrically and have a configuration that enables air to pass through the inside. The actuators 81a, 8Th also function as supply pipes when supplying compressed air to the air springs 6a, 6b.

[0053] By causing the actuators 81a, 8Th to expand and retreat (contract) and thus engaging (fitting) and disengaging the outer peripheral (surfaces) of the inner stoppers 87a, 87b and the inner peripheral (surfaces) of the stopper cover plates 88a, 88b, the rigidities in the longitudinal direction of the air springs 6a, 6b can be changed.

[0054] Next, the actions in Example 2 shown in FIG. 9 will be described referring to FIG. 10 and FIG. 11.

In FIG. 9, if the direction of travel of the railway vehicle is the arrow E, the control device 7 detects the direction of travel of the railway vehicle, causes the actuator 81a of the front truck 2a to contract and causes the actuator 81b of the rear truck 2b to expand. At this point, in the air spring 6a of the front truck 2a, with the contraction of the actuator 81a, the distance between the inner stopper 8Th and the stopper cover plate 88a expands and the inner stopper 87a and the stopper cover plate 88a are disengaged from each other, as shown in FIG. 10. Therefore, even if the air spring 6a is longitudinally displaced when passing through a curve, the inner stopper 87a and the stopper cover plate 88a do not contact (come into contact with) each other and the initial longitudinal rigidity of the air spring 6a is maintained.

[0055] Meanwhile, in the air spring 6b of the rear truck 2b, with the expansion of the actuator 81b, the distance between the inner stopper 87b and the stopper cover plate 88b decreases and the inner stopper 87a and the stopper cover plate 88a are engaged with each other, as shown in FIG. 11. Therefore, if the air spring Gb is longitudinally displaced (deformed) when passing through a curve, the inner stopper 87b and the stopper cover plate 88b contact (come into contact with) each other.

As the inner stopper 87b and the stopper cover plate 88b contact each other, the shear deformation of the multilayer rubber 66b is restricted and therefore the rigidity of the multilayer rubber 66b increases to be equivalent to infinity.

The longitudinal rigidities of the air springs 6a, 6b are expressed by the sums of the longitudinal rigidities of the diaphragms 63a, 63b and the longitudinal rigidities of the multilayer rubbers 66a, 66b (serial rigidities). Therefore, if the rigidity of the multilayer rubber 66b becomes equivalent to infinity, the longitudinal rigidity of the air spring 6b can be made higher than the longitudinal rigidity of the air spring Ca.

[00571 Also in this example, the factors that cause the steering moments and the resistance moments acting on the front truck 2a and the rear truck 2b, and the details of these moments are similar to FIG. 5.

Therefore, again, in this example, the lateral force H on the front truck 2a and the lateral force G on the rear truck 2b can be reduced by switching the longitudinal rigidity of the air spring 6a of the front truck 2a and the longitudinal rigidity of the air spring Gb of the rear truck 2b according to the direction of travel of the railway vehicle by the operation of the actuators Sta, 81b.

[0058] In short, in the front truck 2a passing through a curve, the steering moment (sun of the respective moments in the direction of steering (turning)) and the resistance moment (sum of the respective moments in the reverse direction of the direction of steering) are balanced with each other.

Therefore, since the directicn of the moment K due to the lateral force H and the direction of the moment C due to the air spring reaction forces A, A' are in the opposite (reverse) directions to each other, if the moment C, which is the resistance moment, is reduced, the moment K, which is the steering moment balanced with the resistance moment, is reduced, too.

[00591 By causing the actuator 81a to contract and thus maintaining the longitudinal rigidity of the air spring 6a to a low level, the moment c due to the air spring reaction forces A, A' forming the resistance moment can be reduced. With this reduction in the resistance moment C, the moment K due to the lateral force H forming the steering moment is reduced.

Therefore, the lateral force H, which is the cause of the moment K, is consequently reduced as well.

[0060] Thus, in the front truck 2a, since the longitudinal rigidity of the air spring 6a has the initial value and the moment C due to the air spring reaction forces A, A' forming the resistance moment is reduced on the basis of the relation between the steering moment and the resistance moment shown in FIG. 5, the steering moment K due to the lateral force H forming the steering moment is reduced accordingly.

[0061] Meanwhile, also in the rear truck 2b, the balanced state between the steering moment and the resistance moment is maintained. Therefore, by increasing the longitudinal rigidity of the air spring 6b is increased and the moment D due to the air spring reaction forces B, B', which is the steering moment, the moment J due to the lateral force G, which is the steering moment, is consequently reduced and the lateral force G on the rear truck 2b can be reduced.

[0062] Moreover, also in the rear truck 2b passing through a curve, the steering moment (sum of the respective moments in the direction of steering (turning)) and the resistance moment (sum of the respective moments in the reverse direction of the direction steering) are similarly balanced with each other.

Therefore, since the directicn of the moment J due to the lateral force G and the direction of the moment D due to the air spring reaction forces B, B' are the same direction, increasing the moment ID enables decrease in the moment J due to the lateral force G. [0063] By thus causing the actuator Bib to expand and maintaining the longitudinal rigidity of the air spring 6b at a high level, the moment D due to the air spring reaction forces B, B' can be increased. Consequently, the moment J is reduced by the amount corresponding to the increase in the moment D, which is the steering moment, and therefore the lateral force G, which is the cause of the moment J, is consequently reduced as well.

Since the lateral force H on the front truck 2a and the lateral force C on the rear truck 2b are effectively reduced by the above actions, the wear of the rails and wheels can be suppressed and squeals between these can be reduced.

[00641 The operations of the actuators 81a, Bib when the direction of travel of the railway vehicle is the arrow E, and the advantageous effect that the lateral force G and the lateral force H are ultimately reduced, are described above. However, when the direction of travel is the arrow F in FIG. 9 and the truck 2a is the rear truck while the truck 2b is the front truck, the expansion and contraction operations of the actuators 81a, 81b are opposite (reverse) to the above example. The control device 7 sends commands so as to cause the actuator 81a expand and the actuator Bib to contract.

[0065] In this example, since no installation space for the actuators on the bottom surface of the vehicle body is needed, unlike Example 1, the effect that the degree of freedom in design is increased, such as an ability to arrange other devices near the air springs on the bottom surface of the vehicle body, can be expected as well.

The initial values of the longitudinal rigidities of the air springs 6a, 6b are set similarly to Example 1.

[0066]

[Example 3]

Example 3 of the invention will be described.

FIG. 12 is a plan view of a vehicle schematically showing railway vehicle trucks according to this example, which includes a control device 7 and air supply/discharge valves 89a, 89b. In FIG. 12, when the direction of travel of the railway vehicle is the arrow E, the truck 2a is the front truck and the truck 2b is the rear truck. When the direction of travel is the arrow F, the truck 2a is the rear truck and the truck 2b is the front truck.

[0067] When the direction of travel of the railway vehicle is the arrow E, the control device 7 detects the direction of travel of the railway vehicle and actuates the air supply/discharge valves 89a, 89b which adjust the air pressures of the air springs 6a, 6b.

That is, with respect to the air spring 6a of the front truck 2a, inside air in the diaphragm 63a is discharged to lower internal pressure, whereas with respect to the air spring 6b of the rear truck 2b, air is supplied into the diaphragm 63b to raise internal pressure.

The longitudinal rigidity of the air spring 6a of the front truck 2a where internal pressure is lowered decreases, and the longitudinal rigidity of the air spring 6b of the rear truck 2b where internal pressure is raised increases.

[0068] As shown in FIG. 5, in the front truck 2a and the rear truck 2b, the steering moment (sum of the respective moments in the direction of steering (turning)) and the resistance moment (sum of the respective moment in the reverse direction of the direction of steering) are balanced, as in Examples 1 and 2.

Therefore, in the front truck 2a, since the direction of the moment K due to the lateral force H and the direction of the moment C due to the air spring reaction forces A, A' are the opposite (reverse) directions, if the moment C, which is the resistance moment, is reduced, the moment K due to the lateral force H is reduced. As the moment K is reduced, the lateral force H, which is the cause of the moment K, is consequently reduced.

[0069] Meanwhile, in the rear truck 2b, since the direction of the moment J due to the lateral force 0 and the direction of the moment D due to the air spring reaction forces B, B' are the same direction, if the moment D is increased, the amount of moment corresponding to the increase in the moment D is subtracted from the moment J due to the lateral force C, and the moment J decreases. As the moment J is reduced, the lateral force G, which is the cause of the moment J, is consequently reduced.

[0070] The operations when the direction of travel of the railway vehicle is the arrow E are described. However, when the direction of travel is the arrow F in FIG. 12 and the truck 2a is the rear truck while the truck 2b is the front truck, the control device 7 outputs commands so as to supply air to the air spring 6a and discharge air from the air spring 6b.

In this example, since actuators and cover plates are not needed, unlike Examples 1 and 2, the effect that the degree of freedom in the design of devices under the floor is increased and the effect that lighter weight can be facilitated are achieved.

[0071]

[Example 4]

Examples 1 to 3 relates to a bogie vehicle in which both ends in the longitudinal direction of a vehicle body is supported by two trucks. However, Example 4 is applied to articulated vehicles in which a truck is arranged below the coupling part between a vehicle and a vehicle and in which the end of one vehicle body is placed above two air springs provided in this truck while the end of the other vehicle body is placed above the end of this one vehicle body.

FIG. 13 and FIG. 14 illustrate the case where the device configuration of Example 2 is applied to articulated vehicles by the two-point air spring support system according to this

example.

[0072] FIG. 13 is a plan view showing an articulated truck 2 and vehicle bodies 1 by the two-point air spring support system.

In the two-point air spring support system, both ends in the direction of width of a bolster 91 extending from the truck frame of one vehicle body la toward the other vehicle body lb are placed on a pair of air springs 6 provided in the articulated truck 2. Then, a coupling device 90 provided in the form of extending from the truck frame of the other vehicle body lb toward the one vehicle body la is coupled to a center part in the direction of width (direction of sleepers) of this bolster 91.

That is, the coupling device 90 of the vehicle body lb is placed on top of the bolster 9]. of the vehicle body la, and the bottom surface of the bolster 91. of the vehicle body la forming the coupling part is elastically supported by the air springs 6 provided in the articulated truck 2.

[0073] When the direction of travel of the railway vehicles is the arrow E, the vehicle body la is the front vehicle body and the vehicle body lb is the rear vehicle body, as viewed from the articulated truck 2. when the direction of travel is the arrow F, the vehicle body la is the rear vehicle body and the vehicle body lb is the front vehicle body.

As described in Example 1 and the like, when passing through a curve, the articulated truck 2 turns within a horizontal plane below the coupling part between the vehicle body la and the vehicle body lb and therefore a relative angle is generated between the articulated truck 2, and the vehicle body la and the vehicle body lb. Moreover, since the air springs 6 are longitudinally displaced corresponding to this relative angle, air spring reaction forces acting on the articulated truck 2 from the vehicle body la are generated.

[0074] The air spring reaction forces acting on the articulated truck 2 from the vehicle body la are in the directions of arrows L, L' and a moment M due to the air spring reaction forces acts on the articulated truck 2 from the vehicle body la.

When the railway vehicles travel in the direction of the arrow E and the vehicle body la is the front vehicle body, the momentM acts as a steering moment which accelerates the turning of the truck. Meanwhile, when the railway vehicles travel in the direction of the arrow F and the vehicle body la is the rear vehicle body, the moment M acts as a resistance moment which prevents the turning of the truck.

[0075] FIG. 14 shows the balance of moments acting on the articulated truck 2 by the air spring two-point support system when passing through a curve. When the railway vehicles travel in the direction of the arrow E and the vehicle body la is the front vehicle body, each moment forming the steering moment include a moment P due to a lateral force N, a moment M due to air spring reaction forces L, L', and a moment c due to other factors such as a longitudinal creep force. Meanwhile, each moment forming the resistance moment includes a moment C due to other factors such as a longitudinal creep force. At this point, as in Example 1, the steering moment (sum of the respective moments in the direction of steering (turning)) and the moment C of the resistance moment (sum of the respective moments in the reverse direction of the direction of steering) are balanced with each other.

[0076] Also, when the railway vehicles travel in the direction of the arrow F and the vehicle body lb is the front vehicle body, the moment in the same direction as the steering moment is a moment F' due to a lateral force N' and a moment e' due to other factors such as a creep force, and the moment in the same direction as the resistance moment is a moment M due to air spring reaction forces L, L' and a moment due to other factors such as a longitudinal creep force. At this point, the steering moment (sum of the respective moments in the direction of steering (turning)) and the resistance moment (sum of the respective moments in the reverse direction of the direction of steering) are balanced with each other.

[0077] In the case where the direction of travel of the railway vehicles is the direction of the arrow E and the vehicle body la is the front vehicle body, the direction of the moment P due to the lateral force N and the direction of the moment M due to the air spring reaction forces L, L' are the same direction. Therefore, if the moment M is increased, a moment corresponding to this increase is subtracted from the moment P. As the moment P is reduced, the lateral force N causing the moment P is consequently reduced.

Similarly, in the case where the direction of travel of the railway vehicles is the direction of the arrow F and the vehicle body lb is the front vehicle body, the direction of the moment P' due to the lateral force N' and the direction of the moment M due to the air spring reaction forces L, L' are the opposite (reverse) directions. Therefore, if the moment M is reduced, the moment P' due to the lateral force N' is reduced as well and the lateral force N' causing the moment P' can be consequently reduced.

[0078] In short, the lateral force N acting on the truck 2 can be reduced by increasing the longitudinal rigidity of the air springs 6 when the vehicle body la supported by the air springs 6 is the front vehicle body (when the direction of travel is the arrow E), and by reducing the longitudinal rigidity of the air springs 6 when the vehicle body lb not supported by the air springs 6 is the front vehicle body (when the direction of travel is the arrow F) [0079] Thus, when the railway vehicles travel in the direction of the arrow E and the vehicle body la is the front vehicle body, the control device 7 outputs a command to cause the actuators 81 to expand, thus increasing the longitudinal rigidity of the air springs 6. At this point, since the moment P due to the lateral force N acting on the truck 2 and the moment M due to the longitudinal rigidity of the air springs 6 are in the sante direction, if the longitudinal rigidity of the air springs increases and the moment H increases, the moment P decreases and therefore the lateral force N causing the moment P decreases.

[0080] Also, for example, in the case where the coupling part configuration shown in FIG. 13 is provided in four places in vehicles of a train set made up of five vehicles, and where the vehicles of this train set travel in the direction of the arrow E and the vehicle bodies on the forward side in the direction of travel are supported by air springs, the longitudinal rigidities of all the air springs in the four coupling parts are increased. This control enables reduction in the lateral force N. [0081] Meanwhile, in the case where the railway vehicles travel in the direction of the arrow F and the vehicle body lb is the front vehicle body, the control device 7 outputs a command to cause the actuators 81 to contract, thus reducing the longitudinal rigidities of the air springs 6 in the four coupling parts. As the longitudinal rigidities o the air springs 6 are lowered, the moment M in the same direction as the resistance moment is reduced.

[0082] At this point, since the moment F' due to the lateral force N' acting on the articulated truck 2 and the moment M 4].

due to the longitudinal rigidity of the air springs 6 are in the opposite directions, if the longitudinal rigidity of the air springs is reduced and the moment M is reduced, the moment P' due to the lateral force is reduced accordingly and therefore the lateral force N' is reduced as well.

[0083]

[Example 5]

FIG. 15 is a plan view showing an articulated truck 2 and vehicle bodies 1 by a four-point air spring support system.

FIG. 15 and FIG. 16 illustrate the case where the device configuration of Example 2 is applied to articulated vehicles by the four-point air spring support system.

In the four-point air spring support system, four air springs in total, made up of a set of two air springs 6a and a set of two air springs 6b, are placed on the top surface of the single truck 2. One end in the longitudinal direction of the vehicle body la is placed and elastically supported on the air springs 6a, and the other end in the longitudinal direction of the vehicle body lb is placed and elastically supported on the air springs 6b.

The vehicle body la and the vehicle body lb are coupled together by a coupling device 92 provided at the one end of the vehicle body la and a coupling device 90 provided at the other end of the vehicle body lb. [0084] When the railway vehicles travel in the direction of the arrow E, the vehicle body la is the front vehicle body and the vehicle body lb is the rear vehicle body. Meanwhile, when the railway vehicles travel in the direction of the arrow F, the vehicle body la is the rear vehicle body and the vehicle body lb is the front vehicle body.

In the case where the railway vehicles travel through a curve in the direction of the arrow E, the articulated truck 2 turns along the curve. Therefore, a relative angle is generated between the articulated truck 2, and the vehicle body la and the vehicle body ib, and the air springs 6 are displaced (deformed) in the longitudinal direction. The displacement of the air springs 6 generates air spring reaction forces acting on the articulated truck 2 from the vehicle bodies la, lb. In the vehicle body la, the reaction forces of the air springs 6a applied to the articulated truck 2 are in the directions of arrows Q, Q' and a moment R is generated in the articulated truck 2.

Meanwhile, in the vehicle body ib, the reaction forces of the air springs 6b applied to the articulated truck 2 are in the directions of arrows 5, 5' and a moment T is generated in the articulated truck 2.

[0085] FIG. 16 shows the balance between the moments acting on the articulated truck 2 by the air spring four-point support system when passing through a curve.

When the railway vehicles travel in the directLon of the arrow E and the vehicle body la is the front vehicle body, the moment in the sante direction as the steering moment is a moment V due to a lateral force U, a moment R due to air spring reaction forces Q, Q', and a moment 11 due to other factors such as a longitudinal creep force. The moment in the same direction as the resistance moment is a moment T due to air spring reaction forces S, 3', and a moment 9 due to other factors such as a longitudinal creep force.

[0086] Meanwhile, when the railway vehicles travel in the direction of the arrow F and the vehicle body lb is the front vehicle body, the moment in the same direction as the steering moment is a moment V' due to a lateral force U', a moment T due to air spring reaction forces 3, 3', and a moment due to other factors such as a longitudinal creep force. The moment in the same direction as the resistance moment is a moment R due to air spring reaction forces Q, Q', and a moment 8' due to other factors such as a longitudinal creep force.

[0087] When the railway vehicles travel in the direction of the arrow E and the vehicle body la is the front vehicle body, the direction of the moment V due to the lateral force U is equal to the direction of the moment R due to the reaction forces Q, Q' of the air springs 6a and opposite to (reverse of) the direction of the moment T due to the air spring reaction forces 3, St of the air springs 6b supporting the rear vehicle body lb. Since the steering moment (sum of the respective moments in the direction of steering (turning)) and the resistance moment (sum of the respective moments in the reverse direction of the direction of steering) are balanced with each other, if the moment R in the same direction as the steering moment is increased, the moment V due to the lateral force U similarly in the same direction as the steering moment decreases accordingly and therefore the lateral force U causing the moment V can be consequently reduced.

[0088] Moreover, if the moment T in the same direction as the resistance moment is reduced, the sum of the resistance moments decreases in itself and the sum of the moments in the same direction as the steering moment decreases so as to be balanced with the sum of the moments in the same direction as this resistance moment.

Therefore, since the moment V due to the lateral force U of the steering moment as a part of the sum of the steering moments is reduced, the lateral force U causing the moment V can be reduced.

[0089] When the railway vehicles travel in the direction of the arrow F and the vehicle body lb is the front vehicle body, the direction of the moment V1 due to the lateral force U' is equal to the direction of the moment T due to the air spring reaction forces 5, 5' of the air springs 6b supporting the front vehicle body lb and opposite to (reverse of) the direction of the moment R due to the air spring reaction forces Q, Q' of the air springs 6a supporting the rear vehicle body la.

[0090] Since the sum of the moments in the direction of the steering direction and the sum of the moments in the direction of the resistance moment are balanced with each other, if the moment T in the direction of the steering moment is increased, the moment V' due to the lateral force U', which is a moment in the direction of the steering moment, decreases and therefore the lateral force U' causing the moment V can be consequently reduced.

[0091] Moreover, if the moment R, which is a moment in the direction of the resistance moment, is reduced, the sum of the moments in the direction of the resistance moment decreases in itself and the sum of the moments in the direction of steering which is balanced with this decreases as well. Therefore, since the moment V1 due to the lateral force U' of the steering moment, which is a moment in the same direction as the steering moment, is reduced, the lateral force U' causing the moment V' can be reduced.

10092] In short, the lateral force acting on the articulated truck 2 can be reduced by increasing the longitudinal rigidity of the air spring supporting the front vehicle body and reducing the rigidity of the air springs supporting the rear vehicle body according to the direction of travel of the railway vehicles.

Thus, when the railway vehicles travel in the direction of the arrow E and the vehicle body la is the front vehicle body, the control device 7 sends an expansion command to the actuators 81a to increase the longitudinal rigidity of the air springs 6a on the forward side in the direction of travel and sends a contraction command to the actuators Bib to decrease the longitudinal rigidity of the air springs 6b on the side opposite to the forward side in the direction of travel.

[0093] With the above control, the longitudinal rigidity of the air springs 6a is increased and the longitudinal rigidity of the air springs 6b is reduced. At this point, since the direction of the moment V due to the lateral force U acting on the articulated truck 2 and the direction of the moment R due to the air springs 6a are the same, if the moment Ft increases, the moment V due to the lateral force U is reduced and therefore the lateral force U causing the moment V is reduced.

[0094] When the railway vehicles travel in the direction of the arrow F and the vehicle body lb is the front vehicle body, the control device 7 sends an expansion command to the actuators 81a to increase the longitudinal rigidity of the air springs 6b on the forward side in the direction of travel and sends a contraction command to the actuators 81b to decrease the longitudinal rigidity of the air springs 6a on the side opposite to the forward side in the direction of travel.

With the above control, since the moment V' due to the lateral force U' acting on the articulated truck 2 and the moment T due to the air spring reaction forces 5, S' of the air springs 6b are in the same direction, if the longitudinal rigidity of the air springs 6b is increased to increase the moment T, the moment V' due to the lateral force U' decreases and therefore the lateral force U' causing the moment V' is consequently reduced.

Since the lateral force U and the lateral force U' are effective reduced by the foregoing actions, the wear of the rails and wheels can be suppressed and squeals generated between these can be reduced.

[0095] As described above, even in the articulated vehicles where the truck is arranged at the coupling part of the railway vehicles, the longitudinal rigidity of the air springs relating to the steering moment may be reduced and the longitudinal rigidity of the air springs relating to the resistance moment may be increased according to the direction of travel when passing through a curve. The initial values of the longitudinal rigidities of the air springs 6a, 6b are set similarly to Example 1.

[0096] In this example, the second example is applied to the articulated truck 2 by the air spring four-point support system.

However, the first and third examples can also be applied to such articulated vehicles.

Also, if a plurality of railway vehicles is coupled to form a train set, the change in the internal pressure of the air springs and the operations of the actuators may be made switchable through the entire train set.

[0097] In each example, the longitudinal rigidity of the air springs on the side that is the forward side in the direction of travel is reduced and the longitudinal rigidity of the air springs on the side that is the rear side in the direction of travel is increased. However, this is not limiting and various changes can be made.

[0098] That is, in Example 1, for example, the initial values of the longitudinal rigidities of the air springs 6a, 6b on the forward side and the rear side in the direction of travel are set in advance to optimum values within a range that does not impair comfortable ride quality and running stability, including the time of straight running and the time of curve running. Meanwhile, when control signals from the control device 7 to the actuators 81a, 81b are not outputted, the actuators 81a, 81b are fixed at positions such that even if the air springs 6a, 6b on the forward side and the rear side in the direction of travel are displaced in the longitudinal direction, the diaphragms 63a, 53b do not come into contact with the cover plates 84a, 84b and that the longitudinal rigidities of the air springs 6 are not changed.

[0099] Then, if a command to increase the longitudinal rigidity of the air springs is sent only to the actuator relating to the air springs on the rear side in the direction of travel, the diaphragms of the air springs on the forward side in the direction of travel do not come into contact with the cover plates and the longitudinal rigidity of the air springs is not changed. This configuration enables simplification of the control by the control device 7 and reduced cost and longer life of the actuators. Such a change can be similarly applied

to Examples 2 to 5.

[0100] Moreover, since the lateral forces generated at the tine of passing through a curve are influenced not only by the radius of curvature (R) of the curve and the running speed but also by the form and specifications of the vehicle and the number of passengers or the like, with respect to each of the longitudinal rigidities of the air springs 6a, 6b in the front truck 2a and the rear truck 2b, optimum values of the amounts of expansion or contraction of the respective actuators 81a, 81b may be called in real time and given as command values on the basis of a database of route information, diagram and the like, including running position information received from ground elements, position information via the GPS, and the radius (R) of the curve, or the like.

[0101] The invention is not limited to the above examples and includes various modifications. For example, the above examples give detailed descriptions in order to explain the invention comprehensibly and the invention is not necessarily limited to having all the configurations described. Also, a part of the configuration in one example can be replaced with the configuration in another example, and the configuration in another example can be added as well. Moreover, with respect to a part of the configuration in each example, addition, deletion, and replacement with another configuration are possible. 5].

[0102] In short, the invention includes configurations for detecting the direction of travel of a railway vehicle by an in-vehicle speed detector, a ground device, at the start of turn-back operation and via the GPS or the like, controlling an actuator as an air spring displacement suppression device in the direction of reducing lateral forces generated when passing through a curve, and adjusting the longitudinal rigidities of air springs elastically supporting the vehicle body, to optimum values.

[Reference Signs List] [0103] 1 vehicle body 2 truck 3 truck frame 4 axle box unit wheelset 6 air spring 7 control device 61 top surface 62 bottom plate 63 diaphragm 66 multilayer rubber 81 actuator 84 cover plate 87 inner stopper 88 stopper cover plate 89 air supply/discharge valve coupling device 91 bolster 92 coupling device support air spring displacement suppression device