Suspension for a tracked vehicle

• US 5,372,212 A
• Filed: 05/10/1994
• Issued: 12/13/1994
• Est. Priority Date: 01/17/1990
• Status: Expired due to Fees

• Current Assignee: Group Lotus PLC (Zhejiang Geely Holding Group Co., Ltd.)
• Original Assignee: Group Lotus PLC (Zhejiang Geely Holding Group Co., Ltd.)
• Inventors: Davis, John P.
• Primary Examiner(s): HILL, MITCHELL
• Application Number:
  US08/240,966
• Time in Patent Office: 217 Days
• Field of Search: 180/9.1, 180/9.52, 280/707, 305/10
• US Class Current: 180/9.1
• CPC Class Codes: B62D 55/116 Attitude or position control of chassis by action on suspension, e.g. to compensate for a slope
• CPC Class Codes: B62D 55/30 Track-tensioning means

Abstract

A suspension system for a tracked vehicle includes a track and an associated wheel assembly a U-track tensioning assembly and a plurality of road wheels are adapted to be disposed adjacent to the surface over which the vehicle is moving and transfer the weight of the vehicle to the surface via the track. A microprocessor is provided to control the track tensioning assembly in response to tensioning signals. In a preferred embodiment, the track tensioning assembly comprises a tensioning wheel which is not a road wheel and a strut connected to the tensioning wheel and operable to apply force to the tensioning wheel, thereby tensioning the track.

Claims

1. A suspension for a tracked vehicle comprising a track extending around an associated wheel assembly, and track tensioning means, the wheel assembly having a plurality of road wheels adapted to be disposed adjacent the surface over which the vehicle is moving and adapted to transfer the weight of the vehicle to the surface via the track, and at least one driven wheel adapted to drive the track, the track tensioning means comprising microprocessor control means for controlling the track tensioning means in response to tensioning signals fed to the control means representative of predetermined input variables;

wherein

the track tensioning means comprises a tensioning wheel in contact with a portion of the track which is not in engagement with the surface over which the vehicle is moving and a tensioning strut for varying the position of the tensioning wheel, the tensioning strut being connected to the tensioning wheel such that the position of the tensioning wheel can be varied without variation in position of any of the road wheels;

the microprocessor control means calculates a desired position for the tensioning wheel; and

the microprocessor control means controls the tensioning strut to move the tensioning wheel to the calculated desired position.

2. A suspension according to claim 1 which further comprises first stage means for rapidly tensioning the track, and in which the microprocessor is adapted to control the first stage means during a high-tension transition in which the track tension is increased such that during an initial stage the first stage means is actuated so as to tension the track relatively rapidly.

3. A suspension according to claim 2 in which following the initial stage the microprocessor control means controls the track tensioning means and first stage means in a second, compensatory, stage so as to advance the track tensioning means to take up the track tension from the first stage means, and thereafter, or simultaneously, move the first stage means back towards their normal operating position.

4. A suspension system according to claim 3 in which the compensatory stage occurs at a slower rate than the initial stage.

5. A suspension for a tracked vehicle according to claim 4 in which a series of adjacent road wheels is provided and the first and last road wheels of the series, being the foremost and hindmost road wheels in the normal direction of travel of the vehicle, are provided with sensors for measuring their displacement relative to the body of the vehicle.

6. A suspension for a tracked vehicle according to claim 5 in which a microprocessor calculates and sums together the distance between the hindmost roadwheel the foremost roadwheel, the distance between foremost roadwheel and the tensioning wheel, the distance between the tensioning wheel and a fixed reference wheel in contact with the track and the distance between the fixed reference wheel and the hindmost wheel and the microprocessor then controls the double or single acting strut to move the tensioning wheel until the sum of distances between the said wheels corresponds to that required for a desired track tension.

7. A suspension according to claim 2 in which first stage means comprises one or more actively controlled road wheels and in which the microprocessor control means is adapted to control the wheel control means during a high-tension transition in which the track tension is increased such that during an initial stage at least one road wheel is urged rapidly downwards towards the surface over which the vehicle is travelling so as to tension the track relatively rapidly.

8. A suspension according to claim 2 in which automatic means for instigating the high-tension transition is provided.

9. A suspension according to claim 8, further comprising sensor means for generating differential braking and acceleration inputs indicative of maneuvering of the vehicle, and wherein the automatic means responds to said inputs indicative of manoeuvering of vehicle.

10. A suspension according to claim 9, wherein said sensor means senses differential braking and acceleration between tracks of the vehicle, and wherein the automatic means respond to said differential braking and acceleration inputs between tracks of the vehicle in order to detect maneuvering of the vehicle.

11. A suspension according to claim 9 in which the automatic means responds to said differential braking inputs between tracks of a vehicle in order to detect maneuvering of the vehicle.

12. A suspension according to claim 9 in which the automatic means responds to said differential acceleration inputs between tracks of a vehicle in order to detect maneuvering of the vehicle.

13. A suspension according to claim 2 in which the microprocessor control means is operable to control the suspension in a stationary locked mode in which, when the vehicle is stationary, the first stage means is moved fully towards its tensioning position and then locked in position, the track tensioning means also being urged to a fully advanced position in which it tensions the track highly so as to lock the track.

14. A suspension according to claim 1 in which actively controlled wheel control means is associated with at least one of the road wheels and controls the position of said road wheel in response to wheel signals fed to the wheel control means by the microprocessor control means.

15. A suspension according to claim 14 in which a series of consecutive adjacent road wheels is provided and the first and last road wheels of the series, being the foremost and-hindmost road wheels relative to the normal direction of travel of the vehicle, have respective associated actively controlled wheel control means controlled by the microprocessor control means.

16. A suspension according to claim 1 in which the track tensioning means is controlled by the microprocessor control means when a rough vehicle ride is detected so as to alter the track tension.

17. A suspension according to claim 16 in which a low pass filter filters signals indicative of heave and/or pitch and/or roll of the vehicle and the filtered signals are supplied to the microprocessor, and the microprocessor calculates the desired position of the track tensioning means for the given relatively steady state of heave or pitch or roll to give the desired track tension and moves the track tensioner accordingly.

18. A suspension according to claim 1 wherein the tensioning strut comprises a single acting strut connected to the tensioning wheel, said single acting strut being operable to force said tensioning wheel against the track to tension the track.

19. A tracked vehicle incorporating a suspension in accordance with claim 1.

20. A method of increasing the tension of the track of a tracked vehicle which has first stage means adapted to tension the track and actively controlled track tensioning means which is not a road wheel, the method comprising the steps of:

rapidly urging the first stage means towards the track in an initial stage in which the rapid movement of the first stage means tensions the track; and

subsequently moving the track tensioning means in a subsequent stage in which the track tensioning means takes up the tension in the track from the first stage means whilst the first stage means is withdrawn back towards its retracted position.

21. A method according to claim 20 in which the movement of the track tensioning means in the subsequent stage is relatively slow in comparison with the movement of the first stage means controlled in the initial stage.