SELF-STEERING FLATCAR AND RAILROAD VEHICLE USING HAVING THIS SELF-STEERING FLATCAR APPLIED THERETO

Abstract

 There is provided a self-steering truck in which travel stability and turning performance are improved, and a railroad vehicle to which the self-steering truck is applied. An active steering damper 10 is extended or shrunk as a whole by driving a DC motor 13 so as to rotate a ball screw 15 and allow a nut 16 into which the ball screw is engaged to spiral back and forth, and thereby wheel axles 2 are steered through a steering link 6. This steering is performed by the active function of the active steering damper 10. The active function can solve the response delay of the self-steering which occurs while moving from a straight line to a steady curve through a transition curve. The active steering damper 10 also has a passive function. The passive function serves as a rigid body with respect to vibration at a frequency of hunting which occurs at the time of moving along a straight line, and exerts a buffering function as a non-rigid body with respect to vibration at another frequency. With this, high-speed travel in a straight line and moving performance along a steady curve can be improved.

Description

Technical Field

[0001] The present invention relates to a truck in which a pair of left and right wheel axles (axle and wheel) are supported by a bogie frame in an independently rotatable manner.

Background Art

[0002] As a truck for supporting a railroad vehicle, there are known a single axle truck in which a single axle is rotatably supported by a bogie frame and left and right wheels are attached to the single axle, and an independently rotatable truck in which wheel axles comprising an axle and a wheel are attached to the left and right of a bogie frame (hereinafter, referred to as monocycle independently-rotatable steering truck).

[0003] As for railroad vehicles, turning performance and travel stability are required, and turning performance is achieved by a self-steering function based on the conicity of a wheel. Improvements of the self-steering function can be achieved by freeing the yawing of the wheel axels. However, when the yawing of the wheel axles is freed, hunting as self-exited vibration is caused, which results in the deterioration of the travel stability.

[0004] In the monocycle independently-rotatable steering truck, since the left and right-wheel axles rotate independently, the self-steering function is excellent and it is possible to correspond to a sharp curve, a yard, or a loop way. Also, it is suitable to a low-floor type because the axle is not extended over the width direction, and it is useful to urban areas or specific spaces (Non-patent document 1).

[0005] There has also been proposed a truck frame active steering truck which achieves travel stability by a passive function and auxilaary control by an active function (Patent document 1).

Non-patent document 1:

Fritz Frederich, Possibilities as yet unknown or unused regarding the wheel/rail tracking mechanism, Development of modem rolling stock running gear, Rail International, November 1985, p33

Patent document 1:

Japanese Patent Application Publication No. 2002-328653

Disclosure of the Invention

Problems to be solved by the Invention

[0006] Since the monocycle independently-rotatable steering truck has a basic structure where the left and right wheel axles independently rotate, it is inferior in damping vibration at a frequency of hunting. Therefore, it is considered to be unsuitable to high-speed travel (travel stability). In addition, the limits of the self-steering are deteriorated as the speed is increased. Consequently, this has been applied only to a low-speed vehicle.

[0007] Also, since the structure provided with a passive function and an active function disclosed in Patent document 1 is a single axle truck having a single axle, it has limits of yawing performance at a curve and the critical speed with respect to hunting is low.

Means for solving the problems

[0008] The object of the present invention is to solve the above-mentioned problem of the monocycle independently-rotatable self-steering truck that cannot be applied to a middle-speed or high-speed vehicle, and can be applied only to a low-speed vehicle.

[0009] In order to solve the above-mentioned problem, according to the present invention, there is provided a self-steering truck comprising a bogie frame, a pair of left and right wheel axles supported by the bogie frame in an independently rotatable manner, a steering link connected to the left and right wheel axles so as to steer the wheel axles, and an active steering damper provided between the steering link and the bogie frame.

[0010] The active steering damper has an active function for steering the wheel axles corresponding to a transition curve and a passive function for improving the travel stability at a high speed and the moving performance along a steady curve.

[0011] Preferably, the active steering damper functions as a rigid body with respect to vibration at a frequency of hunting and functions as a damper at the time of moving along a steady curve. An example of the structure includes a direct-acting type damper provided with a DC motor and a ball screw mechanism rotated by the DC motor, and a rotating type damper.

[0012] The present invention includes a railroad vehicle in which the above-mentioned self-steering truck is provided at least in the front and rear of the vehicle. Also, when another truck is provided in the middle position between the front and rear self-steering trucks or in a position near to either one of the front and rear self-steering trucks, it can be effectively applied to a double-deck railroad vehicle. The truck provided between the front and rear self-steering trucks may be different from the front and rear self-steering trucks.

[0013] More specifically, when the length of the vehicle is 20 m based on conventional standards, the self-steering trucks according to the present invention may be provided in the front and rear of the vehicle in terms of maintenance and application to the existing vehicle. On the other hand, in a case of a double-deck railroad vehicle, the length of the vehicle needs to be larger because of the dead space for stairs. When the length of the vehicle is large, the weight of the vehicle becomes large to keep the rigidity. In this instance, if a single axle truck unit is provided in the middle area, it is possible to prevent the rigidity from being deteriorated, and significantly reduce the weight of the vehicle at the same time.

[0014] A double-deck railroad vehicle (for example, super express, referred to as "Shinkansen" in Japan) may have a structure where another floor as an entrance to a platform is provided at the intermediate height between the first floor and the second floor. In this case, the entrance floor is positioned near to either of the left or the right, and a passageway to the first floor of the neighboring vehicle is provided in a space between the left and right wheel axles of the self-steering truck. Also, a passageway to the second floor of the neighboring vehicle is provided in a position near to the other side of the left or the right where the entrance floor is provided. This structure is a walk-through type where passengers can move to the neighboring vehicle without using stairs, and this is advantageous to elderly persons and handicapped persons.

Brief Description of the Drawings

[0015] 

Figure 1 is a plan view of a self-steering truck according to the present invention;

Figure 2(a) is a cross-sectional view of a direct-acting type active steering damper, and Figure 2(b) is a schematic view explaining the function of the direct-acting type active steering damper;

Figure 3 is a plan view of a self-steering truck according to another embodiment;

Figure 4 is a plan view of another embodiment to which a rotating type active steering damper is applied;

Figure 5 is a side view of the embodiment shown in Figure 4;

Figure 6 is a plan view of a self-steering truck according to another embodiment;

Figure 7 is a plan view of a railroad vehicle to which a self-steering truck according to the present invention is applied;

Figure 8 is a side view of the railroad vehicle to which a self-steering truck according to the present invention is applied;

Figure 9 is a front view of the railroad vehicle to which a self-steering truck according to the present invention is applied;

Figure 10 is a side view of a railroad vehicle according to another embodiment;

Figure 11 is a side view of a railroad vehicle according to another embodiment;

Figure 12 is a side view of a coupling portion of a double-deck railroad vehicle to which a self-steering truck according to the present invention is applied;

Figure 13 is a plan view of part of the coupling portion;

Figure 14 is a view taken from A-A direction of FIG. 12;

Figure 15 is a view showing the attack angle and the lateral displacement amount in a straight area, a transition curve area, and a steady curve area when an active steering damper is not provided; and

Figure 16 is a view showing the attack angle and the lateral displacement amount in a straight area, a transition curve area, and a steady curve area when an active steering damper is provided.

Best Mode for Carrying Out the Invention

[0016] Embodiments of the present invention are described below by referring to the accompanying drawings. Figure 1 is a plan view of a self-steering truck according to the present invention, Figure 2(a) is a cross-sectional view of a direct-acting type active steering damper, and Figure 2(b) is a schematic view explaining the function of the direct-acting type active steering damper.

[0017] A self-steering truck includes a bogie frame 1 having a C-shape in a plan view, and a pair of left and right wheel axles 2 supported by the bogie frame 1 in an independently rotatable manner. The wheel axle 2 is comprised of an axle 4 rotatably supported by an axle box 3, and a wheel 5 fixed to the axle 4. The axle box 3 is supported by the bogie frame 1 in a rotatable manner with respect to the horizontal plane.

[0018] The two wheel axles 2 are coupled by a steering link 6. The steering link 6 is comprised of front and rear members 7 extending from the axle box 3 forward (backward), and a lateral member 9 connected to the front and rear members 7 by pins 8. An active steering damper 10 is provided so as to be connected to the lateral member 9 and the bogie frame 1.

[0019] The active steering damper 10 is comprised of a cylinder 11, and a piston 12 inserted into the cylinder 11 in a slidable manner. Also, a DC motor 13, a reduction gear 14, a ball screw 15 and a nut 16 are incorporated into the cylinder 11. A coupling portion 17 is provided at the ends of the cylinder 11 and the piston 12. A rubber bush 18 is engaged into the coupling portion 17.

[0020] The active steering damper 10 is extended or shrunk as a whole by driving the DC motor 13 so as to rotate the ball screw 15 and allow the nut 16 into which the ball screw is engaged to spiral back and forth, and thereby the wheel axles 2 are steered through the steering link 6. This steering is performed by the active function of the active steering damper 10. The active function can solve the response delay of the self-steering which occurs while moving from a straight line to a steady curve through a transition curve. Although track curvature information is required for the active function, such information can be obtained easily by using a vehicle positioning system which is in practical use for a pendulum vehicle, and a track table.

[0021] As shown in Figure 2 (b), the active steering damper 10 also has a passive function. The passive function serves as a rigid body with respect to vibration at a frequency of hunting which occurs at the time of moving in a straight line, and exerts a buffering function as a non-rigid body with respect to vibration at another frequency. With this, high-speed travel in a straight line and passage performance in a steady curve can be improved. Such passive function can be achieved in a DC motor control system.

[0022] Figure 3 is a plan view of a self-steering truck according to another embodiment. In the above-mentioned embodiment, n electromagnetic damper (electric actuator) is used as the active steering damper 10. However, in this embodiment, the active mechanism and the passive mechanism are provided in series, and a common actuator other than the electric actuator is used as the active mechanism.

[0023] Figure 4 is a plan view of another embodiment to which a rotating type active steering damper is applied, and Figure 5 is a side view of the embodiment shown in Figure 4. In this embodiment, a rotating type active steering damper 20 is positioned above one of the wheels axles 2, and the wheel axles 2 are steered through the steering link 6 in the same manner as mentioned above.

[0024] Figure 6 is a plan view of a self-steering truck according to another embodiment. In this embodiment, without using a mechanical steering link 6, two rotating type active steering dampers 20 are positioned above the wheels axles 2, respectively, and the active steering dampers 20 are electrically interlocked. With this, front and rear members 7, and a lateral member 9 are not required.

[0025] Figure 7 is a plan view of a railroad vehicle to which a self-steering truck according to the present invention is applied, Figure 8 is a side view of the railroad vehicle to which a self-steering truck according to the present invention is applied, and Figure 9 is a front view of the railroad vehicle to which a self-steering truck according to the present invention is applied. In this railroad vehicle, two self-steering trucks are provided in the front and rear of the vehicle 30.

[0026] In the vehicle 30, the bogie frame 1 of the self-steering truck is coupled to a bracket 31 of the vehicle body. Dampers 32 for absorbing vibration in the lateral direction, and dampers 33 for absorbing vibration in the vertical direction are provided between the bogie frame 1 and the vehicle body.

[0027] A towing link 34 is provided between the bogie frame 1 and the bracket 31 of the vehicle body so as to fix a yaw of the bogie frame 1.

[0028] Figure 10 and Figure 11 are a side view of a railroad vehicle according to another embodiment. In the railroad vehicle as shown in Figure 10, another self-steering truck is provided in the middle position with respect to the front-and-back direction of the vehicle 30. With the provision of three self-steering trucks, it is possible to sufficiently bear the load in a case of being applied to a double-deck vehicle or the like. Incidentally, the intermediate self-steering truck does not need to include an active steering damper.

[0029] The intermediate truck is preferably positioned in the middle of the front and rear trucks. With this positioning, since steering of the wheel is not required, a complicated steering mechanism can be eliminated. However, it is necessary to move freely in the lateral direction. Such moving mechanism can be achieved by supporting a truck with a linear slide or with a link mechanism, for example. In this way, basically, the intermediate truck has a structure of moving freely in the lateral direction. However, a passive damper or an active mechanism according to the present invention can be incorporated with respect to lateral movements so as to improve the vibration characteristic and travel stability of the vehicle.

[0030] The intermediate truck is not necessarily positioned in the middle of the vehicle body. It may be provided in a position displaced from the middle for the purpose of improving the weight balance or the axle weight balance of the vehicle body, and arranging underfloor instruments more freely. However, in this instance, it is necessary to add a yawing mechanism which is associated with the lateral movement mechanism, such as an are guide slide or an asymmetric link mechanism.

[0031] Figure 12 is a side view of a coupling portion of a double-deck railroad vehicle to which a self-steering truck according to the present invention is applied, Figure 11 is a plan view of the coupling portion, and Figure 13 is a view taken from A-A direction of FIG. 12. In this embodiment, entrance floors 103 and entrance doors 104 to a platform are provided at the intermediate height between first floors 101 and second floors 102 of double-deck vehicles 100 connected with each other.

[0032] The entrance floors 103 are positioned near to either of the left or the right, and the width of the entrance floors 103 is substantially half the width of the vehicle. There are also provided stairs 105 from the entrance floor 103 to the first floor 101 and stairs 106 from the entrance floor 103 to the second floor 102.

[0033] Also, a first-floor passageway 107 and a second-floor passageway 108 are provided in a coupling portion between the vehicles 100. The first-floor passageway 107 can connect the first floors 101 of the vehicles 100 without any level difference such as stairs by utilizing the space between the wheel axles 2 of the self-steering truck.

[0034] Specifically, in a conventional double-deck vehicle, if the first floor is positioned above the truck, stairs are required to go to the next vehicle in the first floor because the height of a platform is around 1 m. However, with the structure of the present invention, it is not necessary to go up and down the stairs, and the structure of a double-deck vehicle can be improved. Also, by arranging the front and rear entrance doors 104 per vehicle in a dot symmetry with respect to the plan view such as an arrangement in which if the front entrance door 104 is provided on the right side, the rear entrance 104 is provided on the left side, it is effective in terms of the layout.

[0035] Also, one seat of a series of two seats is eliminated in the second floor 102 on the other side with respect to the entrance floor 103, and the second-floor passageway 108 is provided in the obtained space, so as to avoid the interference with the entrance floor 103.

[0036] In this way, since no stairs are provided in the first-floor passageway 107 and the second-floor passageway 108, passengers can easily move in the vehicles, and also travel bags provided with a caster or vendor carts can pass.

[0037] Incidentally, the embodiments shown in drawings are a double-deck railroad vehicle to which the self-steering truck according to the present invention is applied. However, using the structure shown in FIGS. 12-14 apart from the truck can achieve a walk-through effect by eliminating an obstacle such as stairs for moving to the connected vehicle.

Claims

1. A self-steering truck comprising a bogie frame, a pair of left and right wheel axles supported by the bogie frame in an independently rotatable manner, a steering link connected to the left and right wheel axles so as to steer the wheel axles, and an active steering damper provided between the steering link and the bogie frame.

2. The self-steering truck according to claim 1, wherein the active steering damper functions as a rigid body with respect to vibration at a frequency of hunting and functions as a damper at the time of moving along a steady curve by controlling a driving source.

3. The self-steering truck according to claim 1 or 2, wherein the active steering damper is either one of a direct-acting type and a rotating type.

4. A railroad vehicle comprising the self-steering truck according to any one of claims 1-3 which is provided at least in the front and rear of the vehicle.

5. The railroad vehicle according to claim 4, wherein another truck is provided in the middle position between the self-steering trucks provided in the front and rear of the vehicle, or in a position near to either one of the self-steering trucks provided in the front and rear of the vehicle.

6. The railroad vehicle according to claim 4 or 5, wherein the vehicle is a double-deck vehicle in which a floor as an entrance to a platform is provided at the intermediate height between the first floor and the second floor and near to either of the left or the right, and a passageway to the first floor of the neighboring vehicle is provided in a space between the left and right wheel axles of the self-steering truck.

7. The railroad vehicle according to claim 4 or 5, wherein the vehicle is a double-deck vehicle in which a floor as an entrance to a platform is provided at the intermediate height between the first floor and the second floor and near to either of the left or the right, and a passageway to the second floor of the neighboring vehicle is provided in a position near to the other side of the left or the right where the entrance floor is provided.

Drawing