EP2086812B1

EP2086812B1 - Active steering bogie for railway vehicles using leverage

Info

Publication number: EP2086812B1
Application number: EP07851577.2A
Authority: EP
Inventors: Joon-Hyuk Park; Won-Hee You; Hyun-Moo Hur
Original assignee: Korea Railroad Research Institute KRRI
Current assignee: Korea Railroad Research Institute KRRI
Priority date: 2007-12-06
Filing date: 2007-12-18
Publication date: 2015-11-18
Anticipated expiration: 2027-12-18
Also published as: CN101588952A; EP2086812A1; EP2086812A4; KR100916594B1; CN101588952B; JP4994461B2; KR20090059530A; JP2010505703A; WO2009072692A1

Description

Technical Field

The present invention relates to an active steering bogie for railway vehicles, which can improve driving stability of a railway vehicle running at a high speed, thereby increasing the stability of the railway vehicle, so that the railway vehicle is not derailed, and also minimize vibration of wheels and rails during the driving of the railway vehicle, thereby ensuring driving comfort. More particularly, the present invention relates to an active steering bogie for railway vehicles using leverage, in which the structure of links for steering wheel shafts of the bogie is simple, and which can use leverage to actuate the links with a small force, thereby remarkably reducing the weight of the bogie and facilitating maintenance, in accordance with the characteristics of the preamble of independent claim 1.

Background Art

In general, a bogie used in a railway vehicle acts to support the weight of a vehicle body in such a fashion that the weight of the vehicle body is uniformly distributed to respective wheels, and also can freely turn with respect to the vehicle body in order to facilitate straight or curved driving of the railway vehicle.
However, the steering force provided by conventional bogies is not sufficient to alleviate excessive centrifugal force and guide weight, which occur between a wheel and a rail, so that the friction between a wheel flange and a lateral rail face generates high levels of noise and vibration, thereby worsening the driving comfort of passengers. This matter also causes abrasion to the wheels and damage to the rails, so that a severe accident, such as derailment of a railway vehicle, can take place.
In order to overcome the foregoing problems, several structures of active steering bogies have been proposed, one example of which is constructed as in FIG. 1. (In FIG. 1, the right in the drawing is assumed to be the front). As shown in FIG. 1, the steering bogie 10 includes front and rear wheel shafts 12 arranged in front and rear parts of a bogie frame 11, wheels 13 press-fitted onto both ends of the wheel shafts 12, and axle boxes 14 and servo motors 15 fixed to the bogie frame 11. Each of the servo motors 15 is coupled with axle boxes 14 of the front or rear wheel shaft 12 via several links.
The bogie 10 has a pair of steering units, each steering unit including one servo motor 15 and corresponding links combined with the motor 15 in order to separately steer the front wheel shaft 12 and the rear wheel shaft 12.
In the conventional steering bogie 10, constructed as above, when a running railway vehicle detects a railroad track that is curved to the right, a controller (not shown) generates a signal to trigger the servo motor 15. As shown in FIG. 2, each of the servo motors 15 rotates a rotation shaft in the clockwise direction via a speed reducer 16. A first drive link 17, eccentrically hinged to the rotation shaft, is pulled to directly steer the rear right wheel shaft 12 of the steering bogie 10. A second drive link 18 is hinged to a first follower link 19 to rotate a transmission link 20, which in turn rotates a second follower link 21, located at a position opposite the bogie 10, thereby pulling a driven link 22 hinged to the second follower link 21, so that the driven link 22 steers the rear left wheel shaft 12.
In the foregoing, the servo motors 15, the first and second drive links 17 and 18, the first and second follower links 19 and 21, the transmission links 20 and the driven links 22 are symmetrically arranged in front and rear parts of the steering bogie 10, so that the front and rear wheel shafts 12 are steered, in the same fashion, by the rotation of respective servo motors 15.
In the conventional steering bogie 10, when the running railway vehicle detects a railroad track that is curved to the left, the controller (not shown) generates a signal causing the servo motors 15 to rotate in the counterclockwise direction, so that the front and rear wheel shafts 12 of the steering bogie 10 are steered as shown in FIG. 3.
The steering bogie 10 for railway vehicles as described above is constructed to transmit the rotation of the servo motors 15 through the links, thereby steering the front and rear wheel shafts 12 of the bogie 10. However, the steering bogie 10 is difficult to maintain due to the complicated construction of the links, and the weight of the steering bogie 10 is also increased due to the heavy weight of the reducers 16, which are fastened to the servo motors 15 to increase the torque of the servo motors 15.
WO 03/010039 and US 4735149 disclose active steering bogies according to the characteristics of the preamble of claim 1.

Disclosure

Technical Problem

The present invention has been made to solve the foregoing problems with the prior art, and therefore the present invention provides an active steering bogie for railway vehicles using leverage, in which steering links for steering front and rear wheel shafts of the bogie have a simplified construction in order to improve maintainability and steering responsiveness of the bogie, and thus, the steering links can be actuated using a small amount of force from an actuator based on leverage, without the use of a reducer.
The invention provides an active steering bogie for railway vehicles using leverage, in which steering links for steering front and rear wheel shafts of the bogie are provided on both sides of the bogie, and the steering links on both sides of the bogie can steer respective wheel shafts in opposite directions, so that the wheel shaft can be greatly displaced even if the links are displaced a small amount, thereby improving the steering ability of the railway vehicle.

Technical Solution

According to an aspect of the invention for realizing the object, the invention provides an active steering bogie for railway vehicles. The active steering bogie includes a front steering unit, which is hinged to front axle boxes on both sides of a front wheel shaft to steer the front wheel shaft; and a rear steering unit, which is hinged to rear axle boxes on both sides of a rear wheel shaft to steer the rear wheel shaft, whereby the wheel shafts are steered using actuators based on leverage.
According to an embodiment of the invention, each of the front and rear steering units includes a corresponding one of the actuators; a first and a second drive links hinged to a bogie frame to transmit force generated by the actuator; a first and a second follower links, each of which is hinged to a corresponding one of the first and second drive links to steer a corresponding one of the axle boxes; and a transmission link connecting the first and second drive links, which are provided on both lateral portions of the bogie.
According to another embodiment of the invention, the actuators are arranged on both sides of the bogie frame to be symmetric to each other along an oblique line.
Here, the first drive link is hinged to the actuator, and has a first end and a second end on both sides of a first joint, the first end being hinged to the first follower link, and the second end being hinged to the transmission link, which is connected to the second drive link at a position opposite the bogie frame.
The second drive link is hinged at a first end thereof to the transmission link and at a second end thereof to the bogie frame, and the second follower link is hinged inside the second drive link.
In the first drive link the distance from the first joint to the first frame joint is at least four times that from a second joint to the first frame joint.
It is desirable that the actuator be actuated by an electric linear motor.
The first and second follower links are hinge coupled via a second or fifth joint and an axle box joint.
It is desirable that the second or fifth joint be a spherical joint.
It is desirable that the axle box joint be a spherical joint.
It is desirable that a rubber bushing be inserted into a socket of the spherical joint.
Furthermore, in each of the front and rear steering units, the first and second drive links, hinged to the bogie frame and interlocked via the transmission link, are rotated around the first and second frame joint by the actuator, and the first and second follower links hinged to the first and second drive links pull or push to rotate the wheel shaft, whereby the bogie is steered.

Advantageous Effects

As set forth above, the active steering bogie for railway vehicles using leverage has a simplified construction of steering links for steering front and rear wheel shafts of the bogie, which can remarkably improve the maintainability and steering responsiveness of the bogie, and thus, the steering links can be actuated using a small amount of force of an actuator based on leverage without the use of a reducer. Accordingly, the weight of the railway vehicle can be reduced.
Furthermore, according to the invention, the steering links for steering front and rear wheel shafts of the bogie are provided on both sides of the bogie, and the steering links on both sides of the bogie can steer respective wheel shafts in opposite directions, so that the wheel shafts can be greatly displaced even if the links are displaced a small amount, thereby improving the steering ability of the railway vehicle. Accordingly, it is possible to ensure the driving comfort of passengers irrespective of track conditions, such as whether a railroad track along which the railway vehicle is running is linear or curved.

Description of Drawings

FIG. 1 is a perspective view illustrating the construction of a conventional active steering bogie;
FIGS. 2 and 3 are perspective views illustrating operation states of the conventional steering bogie;
FIG. 4 is a side elevation view illustrating a steering bogie of the invention;
FIG. 5 is a perspective view illustrating the steering bogie of the invention;
FIGS. 6 to 9 illustrates the steering bogie steered via links and running along corresponding curved railroad tracks; and
FIG. 10 is a cross sectional view illustrating a coupling structure of steering links.

Best Mode

Hereinafter the present invention will be described more fully with reference to the accompanying drawings, in which an exemplary embodiment of an active steering bogie thereof is shown.
FIG. 4 is a side elevation view illustrating a steering bogie of the invention, FIG. 5 is a perspective view illustrating the steering bogie of the invention, and FIGS. 6 to 9 illustrate the steering bogie steered via links and running on corresponding curved railroad tracks.
In the description of the invention, the right of FIGS. 4 and 5 will be assumed to be the front of the steering bogie 100.
As shown in FIGS. 4 and 5, the active steering bogie 100 for railway vehicles using leverage of the invention includes a front steering unit 200, which is hinged to axle boxes 104 on opposite ends of the front wheel shaft 102 to steer the front wheel shaft 102, and a rear steering unit 200A, which is hinged to axle boxes on opposite ends of the rear wheel shaft 102 to steer the rear wheel shaft 102.
In the steering bogie 100 for railway vehicles, each of the front and rear wheel shafts 102 of a bogie frame 101 is supported by a highly rigid suspension device, and wheels are fastened to opposite ends of the wheel shaft 102 via the axle boxes. The front steering unit 200 acts to steer the front wheel shaft 102 of the bogie 100, and the rear steering unit 200A acts to steer the rear wheel shaft 102 of the bogie 100. When a railway vehicle runs along a curved railroad track, the front steering unit 200 and the rear steering unit 200A act to steer the front and rear wheel shafts 102 in such a fashion that the railway vehicle can smoothly run along the curved railroad track.
Each of the front and rear steering units 200 and 200A includes an actuator 201, a first and a second drive links 203 and 203a, which are hinged to the bogie frame 101 and transmit force from the actuator 201, a first and a second follower links 204 and 204a, hinged to respective first and second drive links 203 and 203a to steer the axle boxes 104, and a transmission link 205 connecting the first and second drive links 203 and 203a, which are disposed at opposite lateral portions of the bogie 100, with each other.
As shown in FIGS. 4 and 5, the first and second drive links 203 and 203a are hinged to the bogie frame 101, the first and second drive links 203 and 203a are hinged to the first and second follower links 204 and 204a, and the first and second drive links 203 and 203a on the opposite sides of the bogie 100 are interlocked with each other via the transmission link 205.
Furthermore, the actuators 201, which drive the first and second drive links 203 and 203a of the front and rear steering units 200 and 200A, are fixed to opposite parts of the frame 101 of the bogie 100, in such a fashion that the front steering unit 200 and the rear steering units 200A are set to be symmetric along a diagonal line. This consequently makes the same weight act on opposite parts of the bogie 100, thereby increasing the driving stability of the railway vehicle.
When the first drive links 203 of the bogie 100 are driven by the actuators 201 of the front steering unit 200 and the rear steering unit 200A, as constructed above, angular displacement is transmitted from the first drive links 203 to the second drive links 203a through the transmission links 205.
The first drive link 203 is hinged to the actuator 201, in which one portion of the first drive link 203 corresponding to the first joint 230 is hinged to the first follower link 204, and in which the other portion of the first drive link 203 is hinged to the transmission link 205 and is connected, via the transmission link 205, to one end of the second drive link 203a in the opposite part of the bogie frame 101. The second drive link 203a is in turn hinged, at the other end thereof, to the bogie frame 101, and the second follower link 204a is hinged to the inside of the second drive link 203a.
That is, as the first and second drive links 203 and 203a rotate in the same direction due to the transmission link 205, the first and second follower links 204 and 204a generate displacement in opposite directions, thereby rotating the wheel shaft 102.
The first drive link 203 acts as a lever to transmit force from the actuator 201 to the first follower link 204 by amplifying the force. The distance from the first frame joint 240 of the first drive link 203 to the first joint 230, by which the actuator 201 is hinged to the first drive link 203, is preferably four or more times the distance from the first frame joint 240 to a second joint 250, by which the first drive link 203 is hinged to the first follower link 204.
As mentioned above, the first and second drive links 203 and 203a act as a lever to transmit the force from the actuators 201 to the first and second follower links 204 and 204a by amplifying the force in order to steer the wheel shafts 102. Accordingly, even if the actuators 201 are implemented in the form of a well known electric linear motor, they can satisfactorily steer the wheel shafts 102 via the first and second drive links 203 and 203a without the use of a speed reducer.
Although the actuators 201 can be implemented not only with an electric linear motor but also with a hydraulic actuator or a pneumatic actuator, the hydraulic or pneumatic actuator requires additional hydraulic or pneumatic lines to be provided, in addition to an actuator pump, thereby complicating the construction. Accordingly, it is preferable to use an electric linear motor.
It is preferable that the second joint 250 and a fifth joint 280, by which the first and second drive links 203 and 203a are hinged to the first and second follower links 204 and 204a, and axle box joints 220, by which the first and second drive links 203 and 203a are hinged to the axle boxes 104, be implemented with a spherical joint. Accordingly, the spherical joints, such as the second and fifth joints 250 and 280 and the axle box joints 220, can absorb axial displacement of the wheel shafts 102 generated by the first and second follower links 204 and 204a in the steering of the wheel shafts 102 of the bogie 100, so that the wheel shaft 102 can freely rotate without restriction.
In addition, a rubber bushing 107 is inserted into a socket 106 of each of the spherical joints in order to absorb vibrations produced when the railway vehicle is running, or vibrations or impacts produced when the first and second follower links 204 and 204a rotate the wheel shafts 102, thereby enhancing the driving stability of the railway vehicle.
The operation of the invention having the above-mentioned construction will be described as follows:

When a running railway vehicle having the steering bogie 100 of the invention detects a curved section of railroad track, a controller (not shown) generates a steering signal, which triggers the operation of the actuator 201 to steer the wheel shafts 102 of the bogie 100, so that the railway vehicle can stably run along the curved section of railroad track.

The actuators 201 operate in response to the steering signal, which the controller generates when a curved section of railroad track is detected. Then, the actuators 201 fixed to the opposite parts of the frame 101 of the bogie 100 operate in opposite directions to thus steer the wheel shafts 102. That is, when a rod 202 of one of the actuators 201 protrudes out, the rod 202 of the other one of the actuators 201 retracts into the housing of the actuator 201.
The bogie shown in FIG. 5 moves along the railroad track, from left to right in the drawing, the right and the left of the bogie are set based on the moving direction thereof, and the moving direction of the bogie is assumed to be to the front, or forward.
When the running railway vehicle reaches a section of railroad track that is curved to the right, the controller (not shown) detects the curved railroad track and generates a steering signal. In response to the steering signal from the controller, the rod 202 of the actuator 201 of the rear steering unit 200A, which is fixed to the right part of the bogie frame 101, as shown in FIG. 6, protrudes out to rotate the drive link 202 in the counterclockwise direction around the first frame joint 240. The first drive link 203, rotating in the counterclockwise direction, pulls the first follower link 204, which is hinged to the right axle box 104 of the rear wheel shaft 102. Then, the second drive link 203a of the rear steering unit 200A of the bogie 100, which is connected to the first drive link 203 via the transmission link 205, rotates in the counterclockwise direction around the second frame joint 290 to push the left axle box 104 of the rear wheel shaft 102 and the second follower link 204a, thereby rotating the wheel shaft 102.
Here, the first drive link 203 of the bogie 100 is provided on both sides of the first frame joint 240 with the first joint 230, which is hinged to the actuator 201, and the second joint 250, which is hinged to the first follower link 204, so as to rotate in the counterclockwise direction to pull the first follower link 204. Conversely, the second drive link 203a of the bogie 100 is provided with the fourth joint 270, to which the second drive link 203a and the transmission link 205 are hinged, and with the second frame joint 290, by which the second drive link 203a is hinged to the bogie frame 101 on both sides of the fifth joint 280, by which the second drive link 203a is hinged to the second follower link 204a, so as to rotate in the counterclockwise direction, thereby pushing the second follower link 204a.
Simultaneously with the rear wheel shaft 102 of the bogie 100, rotated by the rear steering unit 200A, the rod 202 of the actuator 201 of the front steering unit 200, which is fixed to the left part of the bogie, retracts into the housing of the actuator 201 in response to the steering signal from the controller, thereby rotating the first drive link 203 in the counterclockwise direction around the first frame joint 240. The first drive link 203, rotating in the counterclockwise direction, pushes the first follower link 204, which is hinged to the left axle box 104 of the front wheel shaft 102, and the second drive shaft 203a of the front steering unit 200 of the bogie 100, which is connected to the first drive link 203 via the transmission link 205, rotates in the counterclockwise direction around the second frame joint 290 to pull the second follower link 204a of the front wheel shaft 102, thereby rotating the wheel shaft 102.
Here, the first drive link 203 of the bogie 100 is provided with the first joint 230 and the second joint 250 on both sides of the first frame joint 240, so as to rotate in the counterclockwise direction, thereby pushing the first follower link 204, whereas the second drive link 203a of the bogie 100 is provided with the fourth joint 270 and the second frame joint 290 on both sides of the fifth joint 280, so as to rotate in the counterclockwise direction, thereby pulling the second follower link 204a.
As mentioned above, when the running railway vehicle reaches a section of railroad track that is curved to the right, the controller (not shown) detects the curved section of railroad track and generates a steering signal. In response to the steering signal from the controller, the rod 202 of the actuator 201 of the rear steering unit 200A protrudes out, and the rod 202 of the actuator 201 of the front steering unit 200 retracts into the actuator housing. This consequently rotates the front and rear wheel shafts 102 of the bogie 100, so that the railway vehicle can stably run along the section of railroad track that is curved to the right, as shown in FIG. 7.
Furthermore, when the running railway vehicle reaches a section of railroad track that is curved to the left, the controller (not shown) detects the curved railroad track and generates a steering signal. In response to the steering signal from the controller, the rod 202 of the actuator 201 of the rear steering unit 200A retracts into the actuator housing, as shown in FIG. 8, and the rod 202 of the actuator 201 of the front steering unit 200 protrudes out. This consequently rotates the front and rear wheel shaft 102 of the bogie 100, so that the railway vehicle can stably run along a section of railroad track that is curved to the left.
The second joints 250, the fifth joints 280 and the axle box joints 220 of the first and second follower links 204 and 204a are implemented with a spherical joint. The spherical joint is adapted to absorb axial displacement of the wheel shaft 102, which occurs when the first and second follower links 204 and 204a steer the wheel shaft 102 of the bogie 100, thereby allowing the wheel shaft 102 to freely rotate without being restricted by the axial displacement, so that the railway vehicle can stably run along the curved railroad track.
Here, a rubber bushing 107 is inserted between a ball 105 and a socket 106 of the spherical joint, so as to absorb vibration produced when the railway vehicle is running, or vibration or impacts produced when the first and second follower links 204 and 204a are rotating the wheel shafts 102, thereby enhancing the driving stability of the railway vehicle.

Industrial Applicability

As set forth above, the active steering bogie for railway vehicles of the present invention can improve the driving stability of a railway vehicle running at a high speed, thereby increasing the stability of the railway vehicle, so that the railway vehicle is not derailed, and also minimize the vibration of wheels and rails during the driving of the railway vehicle, thereby ensuring driving comfort. More particularly, the active steering bogie for railway vehicles using leverage of the present invention has a simple structure of links for steering wheel shafts of the bogie and can use leverage to actuate the links with a small force, thereby remarkably reducing the weight of the bogie and facilitating maintenance.

Claims

An active steering bogie (100) for railway vehicles, comprising:
a front steering unit (200), which is hinged to front axle boxes (104) on both sides of a front wheel shaft (102) to steer the front wheel shaft (102); and

a rear steering unit (200A), which is hinged to rear axle boxes (104) on both sides of a rear wheel shaft (102) to steer the rear wheel shaft (102), the wheel shafts (102) being steered by actuators (201) using leverage,
characterised in that each actuator comprises an electric linear motor,
wherein each of the front and rear steering units (200, 200A) includes:
a corresponding one of the actuators (201);

a first and a second drive links (203 and 203a) hinged to a bogie frame (101) to transmit force generated by the actuator (201), wherein the first drive link (203) is hinged to the actuator (201);

a first and a second follower links (204 and 204a), each of which is hinged to a corresponding one of the first and second drive links (203, 203a) to steer a corresponding one of the axle boxes (104); and

a transmission link (205) connecting the first and second drive links (203, 203a), which are provided on both lateral portions of the bogie (100).
The active steering bogie (100) according to claim 1,
characterised in that the actuators (201) are arranged on both sides of the bogie frame (101) to be obliquely symmetric to each other.
The active steering bogie (100) according to claim 1,
characterised in that
the first drive link (203) is hinged to the actuator (201), and has a first end and a second end on both sides of a first joint (230), the first end being hinged to the first follower link (204), and the second end being hinged to the transmission link (205), which is connected, to the second drive link (203a) in an opposite portion of the bogie frame (101).
The active steering bogie (100) according to claim 3,
characterised in that
the second drive link (203a) is hinged, at a first end thereof, to the transmission link (205), and at a second end thereof, to the bogie frame (101), and the second follower link (204a) is hinged inside the second drive link (203a),
The active steering bogie (100) according to claim 3,
characterised in that,
in the first drive link (203), the distance from the first joint (230) to a first frame joint (240) is at least four times that from a second joint (250) to the first frame joint (240).
The active steering bogie (100) according to claim 1,
characterised in that
the first and second follower links (204 and 204a) are hinge-coupled via a second joint (250) or fifth joint (280) and an axle box joint (220).
The active steering bogie (100) according to claim 6,
characterised in that
the second joint (250) or fifth joint (280) comprises a spherical joint.
The active steering bogie (100) according to claim 6,
characterised in that
the axle box joint (220) comprises a spherical joint.
The active steering bogie (100) according to claim 7 or 8,
characterised in that
a rubber bushing (107) is inserted into a socket (106) of the spherical joint.
The active steering bogie (100) according to claim 1,
characterised in that,
in each of the front and rear steering units (200 and 200A), the first and second drive links (203 and 203a) hinged to the bogie frame (101) and interlocked via the transmission link (205) are rotated around first and second frame joints (240, 290) by the actuator (201), and the first and second follower links (204, 204a) hinged to the first and second drive links (203, 203a) pull or push to thus rotate the wheel shaft (102), whereby the bogie (100) is steered.
The active steering bogie (100) according to any claims hereinbefore, characterised in that
each first drive link (203) is configured to act as a lever to transmit force from the respective actuator (201) to the first follower link (204) by amplifying the force in order to steer the respective wheel shaft (102).
The active steering bogie (100) according to any claims hereinbefore, characterised in that, in each first drive link (203) hinged to the actuator (201), one portion of the first drive link (203) corresponding to a first joint (230) is hinged to the first follower link (204), and the other portion of the first drive link (203) is hinged to the transmission link (205) and being connected, via the transmission link (205), to one end of the second drive link (203a) in the opposite part of the bogie frame (101), wherein the second drive link (203a) is in turn hinged, at the other end thereof, to the bogie frame (101), and the second follower link (204a) is hinged to the inside of the second drive link (203a).
The active steering bogie (100) according to any claims hereinbefore, characterised in that the first and second drive links (203, 203a) are configured to rotate in the same direction due to the transmission link (205), so that the first and second follower links (204, 204a) are capable to generate displacement in opposite directions, thereby rotating the wheel shaft (102).
The active steering bogie (100) according any claims hereinbefore characterised in that the actuators (201) are configured to operate in response to a steering signal, which a controller is able to generate when a curved section of railroad track is detected.
The active steering bogie (100) according to any claims hereinbefore, characterised in that the actuators (201) fixed to the opposite parts of the bogie frame (101) are each provided with protruding rod (202) and are configured to operate in opposite directions to steer the wheel shafts (102) so that when a rod (202) of one of the actuators (201) protrudes out, the rod (202) of the other one of the actuators (201) retracts into the housing of the actuator (201), and viceversa.