Wheel assembly for a vehicle guided on a railway track

Abstract

The invention concerns a vehicle guided on a railway track comprising a chassis and at least one wheel assembly interconnected to the chassis and a method for steering said vehicle. The wheel assembly comprises a cross-member having a first end to which a first hub is interconnected by a first steering joint and a second end to which a second hub is interconnected by a second steering joint. A first wheel is attached to the first hub rotatable around a first rotation axis and a second wheel is attached to the second hub rotatable around a second rotation axis. A first sensor determines the lateral position of the first sensor with respect to the rail. The first sensor is attached to the first hub and is, with respect to a direction of travel arranged in front of the supporting area of the first wheel in a horizontal direction spaced a distance A1 apart. The first sensor is interconnected to an actuator by a control unit which calculates a steering angle for the at least one interconnected wheel depending on the determined position of the first sensor.

Claims

1. A vehicle guided on a railway track comprising a chassis and at least one wheel assembly interconnected to the chassis comprising: a. a static cross-member having i. a first end to which a first hub is interconnected by a first steering joint swiveling about a first steering axis arranged in a vertical manner, ii. a second end to which a second hub is interconnected by a second steering joint swiveling about a second steering axis arranged in a vertical manner, and b. a first wheel attached to the first hub rotatable around a first rotation axis and a second wheel attached to the second hub rotatable around a second rotation axis, c. the first wheel and the second wheel each comprise a rolling surface which during operation interacts with a rail of a railway track by a supporting area, wherein a center distance between each steering axis and a center of the related supporting area is within a maximum distance of 0.1 m, and d. a first sensor to determine a lateral position of the first sensor with respect to the rail, i. said first sensor being attached to the first hub, ii. said first sensor being arranged with respect to a direction of travel in front of the supporting area of the first wheel in a horizontal direction spaced a distance A1 apart with respect to the center of the respective supporting area, wherein the distance A1 is in the range of 0.1-1.2 m e. an actuator interconnected to at least one of the first wheel and the second wheel to swivel the at least one interconnected wheel around the respective steering axis by a steering angle, wherein the at least one interconnected wheel comprises the first wheel, the second wheel, or both the first wheel and the second wheel, and f. the first sensor is interconnected to the actuator by a control unit which calculates a steering angle for the at least one interconnected wheel depending on the determined lateral position of the first sensor.

2. The vehicle guided on the railway track according to claim 1, wherein the at least one wheel assembly comprises a second sensor which is attached to the second hub, said second sensor being arranged with respect to the direction of travel in front of the supporting area of the second wheel in a horizontal direction spaced a distance A2 apart with respect to the center of the related supporting area.

3. The vehicle guided on the railway track according to claim 2, wherein the at least one wheel assembly comprises a third sensor which is attached to the first hub, the third sensor being arranged with respect to the direction of travel in back of the supporting area of the first wheel in a horizontal direction spaced a distance A3 apart with respect to the center of the related supporting area.

4. The vehicle guided on the railway track according to claim 3, wherein the distance A1 and the distance A3 are equal.

5. The vehicle guided on the railway track according to claim 3, wherein the at least one wheel assembly comprises a fourth sensor which is attached to the second hub, said fourth sensor being arranged with respect to the direction of travel in back of the supporting area of the second wheel in a horizontal direction spaced a distance A4 apart with respect to the center of the respective supporting area.

6. The vehicle guided on the railway track according to claim 5, wherein the at least one wheel assembly comprises a fifth sensor which is interconnected to the chassis and to the control unit, wherein the control unit determines out of measured quantities of the fifth sensor one or more of a track type, a track curvature, and track anomalies of the rails in front of the wheel assembly in the direction of travel.

7. The vehicle guided on the railway track according to claim 1, wherein the first hub and the second hub of the at least one wheel assembly are interconnected to each other by a steering rod.

8. The vehicle guided on the railway track according to claim 1, wherein the actuator of the at least one wheel assembly is interconnected to the cross-member.

9. The vehicle guided on the railway track according to claim 1, wherein the actuator of the at least one wheel assembly is in a transversal direction arranged between the wheels of a wheel assembly.

10. The vehicle guided on the railway track according to claim 1, wherein the first sensor of the at least one wheel assembly measures the lateral position of the first sensor with respect to an inner guiding edge or flank of the rail.

11. The vehicle guided on the railway track according to claim 10, wherein the rail comprises a groove acting as the inner guiding edge for the first sensor.

12. The vehicle guided on the railway track according to claim 11, wherein the first sensor of the at least one wheel assembly determines the lateral position of the first sensor with respect to one or more of at least one upper edge and at least one flank of the groove.

13. The vehicle guided on the railway track according to claim 1, wherein the first sensor of the at least one wheel assembly is one or more of an inductive sensor, a laser sensor, a capacitive sensor, an ultrasonic sensor, an optical sensor, and a radar sensor.

14. The vehicle guided on the railway track according to claim 1, wherein the sensor of the at least one wheel assembly has a protection means which is positioned in front of the first sensor in respect of the direction of travel.

15. The vehicle guided on the railway track according to claim 1, wherein the first sensor of the at least one wheel assembly is arranged in a height of about 0.04 m-0.5 m above the rail.

16. The vehicle guided on the railway track according to claim 1, wherein the first wheel of the at least one wheel assembly is interconnected to a first brake disc, wherein the first brake disc is arranged outside of the first wheel, and wherein the second wheel of the at least one wheel assembly is interconnected to a second brake disc, wherein the second brake disc is arranged outside of the second wheel.

17. The vehicle guided on the railway track according to claim 1, wherein the at least one wheel assembly comprises (i) a first driving motor which is arranged outside of the first wheel and is interconnected to the first wheel by a first gear box and (ii) a second driving motor which is arranged outside of the second wheel and is interconnected to the second wheel by a second gear box.

18. The vehicle guided on the railway track according to claim 16, wherein the at least one wheel assembly comprises (i) a rotation axis of the first brake disc which is arranged at an angle with respect to the rotation axis of the first wheel and (ii) a rotation axis of the second brake disc which is arranged at an angle with respect to the rotation axis of the second wheel.

19. The vehicle guided on the railway track according to claim 1, wherein the at least one wheel assembly comprises (i) a first brake disc which is arranged inside of the first wheel and a thereto interconnected first brake caliper and is attached to the first hub, and (ii) a second brake disc which is arranged inside of the second wheel and a thereto interconnected second brake caliper and is attached to the second hub.

20. The vehicle guided on a railway track according to claim 1, wherein the control unit is interconnected to a position determining system which provides information to the control unit about a position of the wheel assembly along the rail.

21. The vehicle guided on the railway track according to claim 20, wherein the control unit uses information on the position of the wheel assembly to revert to a stored data-set.

22. The vehicle guided on the railway track according to claim 1, wherein the rolling surface of each of the first wheel and the second wheel is conical or cylindrical or barrel-shaped.

23. The vehicle guided on the railway track according to claim 1, further comprising at least two wheel assemblies, wherein the first sensor of the first wheel assembly is interconnected to the first sensor of the second wheel assembly by the control units.

24. A method for steering a track guided vehicle comprising: a. Providing the track guided vehicle as defined in claim 1; b. Measuring a displacement of the first sensor with respect to a neutral position where a center of the first sensor is above an inner guiding edge of the rail; c. Communicating the measured displacement to the control unit interconnected to the first sensor; d. Calculating a correcting steering angle by the control unit, wherein the correcting steering angle is determined out of the measured displacement of the first sensor; e. Communicating the calculated correcting steering angle to the actuator interconnected to at least one of the first wheel and the second wheel and the control unit; and f. swiveling at least one interconnected wheel around a respective steering axis by the correcting steering angle by the actuator so that the first sensor is in a target position, where a flange of the at least one interconnected wheel has a target displacement to the inner guiding edge of the rail.

25. The method according to claim 24, wherein the target displacement of the flange to the inner guiding edge of the rail is in a range of about 0.001 m-0.06 m.

26. The method according to claim 24, wherein a second sensor is interconnected in front of the second wheel and the first wheel is interconnected to the second wheel via a steering rod, wherein the first sensor and a second sensor attached to the second hub each has an individual neutral position to which a displacement is measured and communicated to the control unit which calculates target positions out of a mean of the measured displacements of the first sensor and the second sensor.

27. The method according to claim 26 wherein a. a third sensor is attached behind the first wheel, and b. a fourth sensor is attached behind the second wheel, c. wherein each of the first sensor, the second sensor, the third sensor and the fourth sensor measures its displacement in respect to an individual neutral position and communicates the same to the control unit, d. and the control unit is i. using the measured displacements of the first sensor and the second sensor to calculate first target positions for the first sensor and the second sensor, wherein absolute values of the displacement of the first sensor and the second sensor are equal, ii. using the measured displacements the first sensor and the third sensor to calculate second target positions of the first sensor and the third sensor, wherein the displacements of the first sensor and the third sensor are equal, iii. using the measured displacements the second sensor and the fourth sensor to calculate third target positions of the second sensor and the fourth sensor, wherein the displacements of the second sensor and the fourth sensor are equal, iv. determining a correcting steering angle by which the actuator steers the first wheel and the second wheel in a defined position, v. wherein in the defined position 1. The first sensor and the second sensor are one of the first target positions, 2. And the first sensor and the third sensor are in one of the second target positions, 3. and the second sensor and fourth sensor are in one of the third target positions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The herein described invention will be more fully understood from the detailed description of the given herein below and the accompanying drawings, which should not be considered as limiting to the invention described in the appended claims.

(2) FIG. 1 schematically shows a first variation of a steerable axle according to the present invention in a perspective view;

(3) FIG. 2 shows a detail of FIG. 1;

(4) FIG. 3 schematically shows the first variation of the steerable axle according to the present invention in a front view;

(5) FIG. 4 shows a detail of FIG. 3;

(6) FIG. 5 shows a variation of the invention derived from FIG. 4;

(7) FIG. 6 shows a cross-section of the steerable axle of FIGS. 1 and 3;

(8) FIG. 7 schematically shows a second variation with a chassis comprising two steerable axles according to the present invention in a perspective view;

(9) FIG. 8 schematically shows the chassis of FIG. 6 in a side view.

DETAILED DESCRIPTION OF THE INVENTION

(10) The foregoing summary, as well as the following detailed description of the preferred variations of the invention, are better understood when read in conjunction with the appended drawings. For the purposes of illustrating the invention, an embodiment that is presently preferred, in which like numerals represent similar parts throughout the several views of the drawings, it being understood, however, that the invention is not limited to the specific methods and instrumentalities disclosed.

(11) FIG. 1 shows a first variation of the wheel assembly 2 according to the invention. The wheel assembly 2 comprises a first and a second wheel 13, 14, each with a wheel flange 17 and wheel rolling surface 18. Each wheel 13, 14 turns around a rotation axis 15, 16 and can be swiveled around a steering axis 11, 12. Both steering axes 11, 12 are orientated above the corresponding rail and in the region of the supporting point 19 between each wheel 13, 14 and the corresponding rail 3. The steerable wheels 13, 14 are further interconnected to a cross member 4 and a steering rod 23. Through the steering rod 23, an actuator 21 can steer both wheels 13, 14 simultaneously. The actuator 21 is attached to the cross-member 4 and is placed between the two wheels 13, 14. In front of and behind each wheel 13, 14 a sensor 20a-d is placed, which is attached to the hub 7, 8 of the wheel 13, 14 through a sensor mounting 34, 35. Hence, if the wheel 13, 14 has a certain angle in respect to the rail 3, the sensors 20a-d are inclined together with the wheel 13, 14. The sensors 20a-d sense its position in respect to an inner guiding edge 24 and/or flank of the rail 3 underneath the same and therefore gains a measure for the angle of the wheel to the respective rail 3. In this case, the sensors 20a-d are inductive sensors, however, other sensing means such as e.g. laser and/or optical sensors are possible.

(12) FIG. 2 shows a detail view (detail D) of the sensor arrangement of sensor 20a of FIG. 1. The first sensor 20a is interconnected to a first sensor mounting 34 which is interconnected to the steerable wheel 13. The height and lateral displacement of the first sensor 20a in respect to the rail 3 can be adjusted through sensor adjustment means 43.

(13) FIG. 3 shows the wheel assembly 2 in a front view, meanwhile FIG. 4 depicts the details of FIG. 3 of the first sensor mounting 34 and the position of the first sensor 20a. Here, the exact placement of the first sensor 20a in respect to the rail 3 can be seen in a neutral position. With help of the adjustment means 43, the sensor 20a is orientated substantially central above the inner guiding edge of the rail 24 in a height preferably between 0.04 m and 0.5 m. The magnetic field 33 from the inductive sensor 20a reaching to the rail 3 is illustrated schematically.

(14) FIG. 5 shows a rail 3 with a groove 25 in which the flange 17 of a wheel 13, 14 is guided. The groove 25 is formed by two flanks 27 and two upper edges of the groove 26. In the case of a grooved railway, the wheel assembly 2 is steered by means of at least one sensor 20 that measures its position in respect to the groove 25. Hereby the sensor may use either upper edges 24 as reference and/or the flanks 27 of the groove 25. Switching of the relevant references and/or combining signals of different sensors is possible if the condition requires it.

(15) FIG. 6 depicts a section view of the first wheel 13 comprising the wheel's rolling surface 18 as well as the wheel flange 17 and wheel spokes 42 turning around a first rotational axis 15. The wheel 13 further comprises a first hub 7 which is not turning around the first rotational axis 15. Therefore, wheel bearings 38 are placed on the first hub 7. The first hub 7 is further interconnected to the cross-member 4 through a first steering joint 9 which comprises a joint shaft 39 and a joint bushing 40 around which the wheel 13 is steerable. This is further indicated by the first steering axis 11 which is placed concentrically within the joint shaft 39. The joint shaft 39 extends through a section of the cross-member 4 and penetrates in a designated depression of the first hub 7. On the cross-member 4 spring assemblies 36 are arranged. Furthermore, the interconnection of the first sensor mounting 34 to the first hub 7 can be seen; meanwhile the interconnection of the wheel 13 to the steering rod 23 to steer the wheel 13 around the first steering axis 11 cannot be seen in this section view.

(16) FIG. 7 and FIG. 8 illustrate the chassis 1 comprising two wheel assemblies 2 according to the invention. On each wheel assembly 2 spring assemblies 36 are attached on the cross-member 4 and a frame 41 is embedded on the spring assemblies 36 of each wheel assembly 2. On both outer sides of the wheel assembly 2, gear boxes 31 are arranged and interconnected to the wheels 13, 14. Driving motors 30 are interconnected to a first end to the gear boxes 31 in a way that the driving motors are placed in-between the two gear boxes 31 on either side of the chassis 1. Hence, the rotational axis of the driving motors 30 and the rotational axis 15, 16 of the wheels 13, 14 are essentially perpendicular to each other and the gearbox 31 is a right angle gear box. A brake disc 29 is interconnected to a second end of each driving motor 30 so that the two brake discs 29 of the two wheels 13, 14 on one rail 3 are in close proximity facing each other. An electromagnetic rail brake 37 is placed underneath the two driving motors 30 on each side of the chassis 1 (on each rail 3) between the two wheels 13, 14.