Suspension system of vehicle

• US 20060151964A1
• Filed: 03/04/2004
• Published: 07/13/2006
• Est. Priority Date: 03/12/2003
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kasamatsu, Akira
• Granted Patent: US 7,390,002 B2
• Time in Patent Office: Days
• US Class Current: 280/5.510
• CPC Class Codes: B60G 17/0162 mainly during a motion involving steering operation, e.g. cornering, overtaking B60G17/0164 takes precedence
• CPC Class Codes: B60G 21/067 between wheels on different axles on the same side of the vehicle, i.e. the left or the right side
• CPC Class Codes: B60G 2800/012 Rolling condition

Abstract

In a suspension system (20) for use in a vehicle including a body, left and right front wheels (10), and left and right rear wheels (12), a front-wheel-associated cylinder device (52) which controls a relative displacement of the left and right front wheels, and a rear-wheel-associated cylinder device (62) which controls a relative displacement of the left and right rear wheels are associated with each other with a working fluid. A first-chamber-associated valve (190) is provided in a first-chamber-associated passage (90) which connects between respective first chambers (74) of the front-wheel-associated cylinder device and the rear-wheel-associated cylinder device, such that the first-chamber-associated valve is located between the first chamber of the front-wheel-associated cylinder device and a first fluid accommodating device (200).

Claims

1. A suspension system (20) for use in a vehicle including a body, left and right front wheels (10), and left and right rear wheels (12), the system comprising:

a front-wheel-associated cylinder device (52;

330;

406) which controls a relative displacement between the left and right front wheels in upward and downward directions, and which includes a housing (70;

334) and a piston (72;

342;

440) fitted in the housing to divide an inner room of the housing into a first fluid chamber (74;

344;

416) and a second fluid chamber (76;

346;

418);

a rear-wheel-associated cylinder device (62;

332;

408) which controls a relative displacement between the left and right rear wheels in the upward and downward directions, and which includes a housing (70;

334) and a piston (72;

342;

440) fitted in the housing to divide an inner room of the housing into a first fluid chamber (74;

344;

416) and a second fluid chamber (76;

346;

418) which correspond to the first and second fluid chambers of the front-wheel-associated cylinder device, respectively;

a first-chamber-associated passage (90;

402) which connects between the respective first fluid chambers of the front-wheel-associated and rear-wheel-associated cylinder devices;

a second-chamber-associated passage (92;

412) which connects between the respective second fluid chambers of the front-wheel-associated and rear-wheel-associated cylinder devices;

at least one fluid accommodating device (200, 206;

404, 414) which is connected to the first-chamber-associated passage at a first connection point (CP1), and is connected to the second-chamber-associated passage at a second connection point (CP2), and which can accommodate an amount of a working fluid present in the first-chamber-associated and second-chamber-associated passages and the front-wheel-associated and rear-wheel-associated cylinder devices, the first-chamber-associated passage including two portions (180, 184) located on opposite sides of the first connection point, respectively, the second-chamber-associated passage including two portions (180, 184) located on opposite sides of the second connection point, respectively;

a first-chamber-associated valve device (190;

400;

500) which is selectively placed in a communication position to communicate the respective first fluid chambers of the front-wheel-associated and rear-wheel-associated cylinder devices, with each other, and a shut-off position to shut off the communication between said respective first fluid chambers;

a second-chamber-associated valve device (230;

410;

510) which is selectively placed in a communication position to communicate the respective second fluid chambers of the front-wheel-associated and rear-wheel-associated cylinder devices, with each other, and a shut-off position to shut off the communication between said respective second fluid chambers; and

the first-chamber-associated valve device being provided in one of the two portions of the first-chamber-associated passage that is nearer than the other portion to a first cylinder device (52;

408) as one of the front-wheel-associated and rear-wheel-associated cylinder devices, the second-chamber-associated valve device being provided in one of the two portions of the second-chamber-associated passage that is nearer than the other portion to a second cylinder device (62;

406) as the other of the front-wheel-associated and rear-wheel-associated cylinder devices.

2. The system according to claim 1, wherein a conversion rate at which an amount of change of a volume of the first fluid chamber (74) of the front-wheel-associated cylinder device (52) is converted into an amount of displacement of a piston (72) of the front-wheel-associated cylinder device, is smaller than a conversion rate at which an amount of change of a volume of the second fluid chamber (76) of the front-wheel-associated cylinder device is converted into an amount of displacement of the piston of the front-wheel-associated cylinder device, and

wherein the first cylinder device comprises the front-wheel-associated cylinder device (52), so that the first-chamber-associated valve device (190) is provided in said one portion of the first-chamber-associated passage (90) that is nearer to the front-wheel-associated cylinder device.

3. The system according to claim 1, wherein a conversion rate at which an amount of change of a volume of the first fluid chamber (416) of the rear-wheel-associated cylinder device (408) is converted into an amount of displacement of a piston (440) of the rear-wheel-associated cylinder device, is smaller than a conversion rate at which an amount of change of a volume of the second fluid chamber (418) of the rear-wheel-associated cylinder device is converted into an amount of displacement of the piston of the rear-wheel-associated cylinder device, and

wherein the first cylinder device comprises the rear-wheel-associated cylinder device, so that the first-chamber-associated valve device (500) is provided in said one portion of the first-chamber-associated passage (402) that is nearer to the rear-wheel-associated cylinder device.

4. The system according to claim 1, further comprising:

a first-chamber-associated bypass passage (218) which communicates the respective first fluid chambers (74) of the front-wheel-associated and rear-wheel-associated cylinder devices (52, 62), with each other, while substantially bypassing the first-chamber-associated valve device (190); and

a second-chamber-associated bypass passage (218) which communicates the respective second fluid chambers (76) of the front-wheel-associated and rear-wheel-associated cylinder devices, with each other, while substantially bypassing the second-chamber-associated valve device (230).

5. The system according to claim 4, further comprising:

a first flow restrictor (220) which is provided in the first-chamber-associated bypass passage (218) and restricts a flow of the working fluid in the first-chamber-associated bypass passage; and

a second flow restrictor (220) which is provided in the second-chamber-associated bypass passage (218) and restricts a flow of the working fluid in the second-chamber-associated bypass passage.

6. The system according to claim 1, wherein said at least one fluid accommodating device comprises:

at least one accumulator (200) which can accommodate the amount of the working fluid present in the first-chamber-associated and second-chamber-associated passages and the front-wheel-associated and rear-wheel-associated cylinder devices; and

at least one accumulator-associated valve (206) which is selectively placed in a communication position to communicate said at least one accumulator with the first-chamber-associated and second-chamber-associated passages (90, 92), and in a shut-off position to shut off the communication between said at least one accumulator and the first-chamber-associated and second-chamber-associated passages.

7. The system according to claim 6, further comprising at least one relief passage (310) which relieves the amount of the working fluid from the first-chamber-associated and second-chamber-associated passages (90, 92) into said at least one accumulator (200), while substantially bypassing said at least one accumulator-associated valve (206).

8. The system according to claim 7, further comprising at least one relief valve (312) which is provided in said at least one relief passage (310) and which is opened when a pressure of the working fluid present in the first-chamber-associated and second-chamber-associated passages (90, 92) exceeds a reference value, so that the amount of the working fluid flows from the first-chamber-associated and second-chamber-associated passages (90, 92) into said at least one accumulator (200), while substantially bypassing said at least one accumulator-associated valve (206).

9. The system according to claim 6, wherein said at least one accumulator-associated valve (206) is normally placed in the communication position.

10. The system according to claim 6, comprising two said accumulator-associated valves (206) which are associated with the first-chamber-associated and second-chamber-associated passages (90, 92), respectively.

11. The system according to claim 10, comprising two said accumulators (200) which are associated with the first-chamber-associated and second-chamber-associated passages (90, 92), respectively.

12. The system according to claim 6, wherein said one accumulator-associated valve (614, 206) is commonly associated with the first-chamber-associated and second-chamber-associated passages (402, 412).

13. The system according to claim 12, wherein said one accumulator (614, 200) is commonly associated with the first-chamber-associated and second-chamber-associated passages (402, 412).

14. The system according to claim 1, wherein the first-chamber-associated valve device comprises a first-chamber-associated mechanical valve (190) which is mechanically switched between a communication position to communicate the respective first fluid chambers (74) of the front-wheel-associated and rear-wheel-associated cylinder devices (52, 62), with each other, and a shut-off position to shut off the communication between said respective first fluid chambers, with a first cylinder pressure based on respective pressures of the respective working fluids in said respective first chambers, and the second-chamber-associated valve device comprises a second-chamber-associated mechanical valve (230) which is mechanically switched between a communication position to communicate the respective second fluid chambers (76) of the front-wheel-associated and rear-wheel-associated cylinder devices, with each other, and a shut-off position to shut off the communication between said respective second fluid chambers, with a second cylinder pressure based on respective pressures of the respective working fluids in said respective second chambers.

15. The system according to claim 14, wherein each of the first-chamber-associated mechanical valve (190) and the second-chamber-associated mechanical valve (230) is normally placed in the communication position thereof and, when a corresponding one of the first and second cylinder pressures exceeds a reference value, the each mechanical is switched from the communication position to the shut-off position.

16. The system according to claim 15, wherein said each of the first-chamber-associated mechanical valve (190) and the second-chamber-associated mechanical valve (230) comprises:

a housing (110);

a valve portion (132) including a valve member (128) and a valve seat (126) which comprise

a first movable member (128);

a second movable member (134) which is movable with the first movable member and which is fitted in the housing to divide an inner room of the housing into a first room (160) on the side of the valve portion and a second room (162) opposite to the first room; and

a biasing device (150) which biases the second movable member in a direction in which the valve member is moved away from the valve seat.

17. The system according to claim 16, wherein the working fluid comprises a working liquid,

wherein said at least one fluid accommodating device (200, 206) can accommodate an amount of the working liquid, and

wherein the second room (162) of said each mechanical valve (190, 230) is connected to said at least one fluid accommodating device.

18. A suspension system (20) for use in a vehicle including a body, left and right front wheels (10), and left and right rear wheels (12), the system comprising:

a front-wheel-associated cylinder device (52;

330) which controls a relative displacement between the left and right front wheels in upward and downward directions, and which includes a housing (70;

334) and a piston (72;

342) fitted in the housing to divide an inner room of the housing into a first fluid chamber (74;

344) and a second fluid chamber (76;

36);

a rear-wheel-associated cylinder device (62;

332) which controls a relative displacement between the left and right rear wheels in the upward and downward directions, and which includes a housing (70;

334) and a piston (72;

342) fitted in the housing to divide an inner room of the housing into a first fluid chamber (74;

344) and a second fluid chamber (76;

346) which correspond to the first and second fluid chambers of the front-wheel-associated cylinder device, respectively;

a first-chamber-associated passage (90) which connects between the respective first fluid chambers of the front-wheel-associated and rear-wheel-associated cylinder devices;

a second-chamber-associated passage (92) which connects between the respective second fluid chambers of the front-wheel-associated and rear-wheel-associated cylinder devices;

at least one fluid accommodating device (200, 206) which is connected to the first-chamber-associated passage at a first connection point (CP1), and is connected to the second-chamber-associated passage at a second connection point (CP2), and which can accommodate an amount of a working fluid present in the front-wheel-associated and rear-wheel-associated cylinder devices, the first-chamber-associated passage including two portions on opposite sides of the first connection point, respectively, the second-chamber-associated passage including two portions on opposite sides of the second connection point, respectively;

a first-chamber-associated valve device (190) which is selectively placed in a communication position to communicate the respective first fluid chambers of the front-wheel-associated and rear-wheel-associated cylinder devices, with each other, and a shut-off position to shut off the communication between said respective first fluid chambers;

a second-chamber-associated valve device (230) which is selectively placed in a communication position to communicate the respective second fluid chambers of the front-wheel-associated and rear-wheel-associated cylinder devices, with each other, and a shut-off position to shut off the communication between said respective second fluid chambers;

the first-chamber-associated valve device comprising a first-chamber-associated mechanical valve (190) which is mechanically switched between a communication position to communicate the respective first fluid chambers (74) of the front-wheel-associated and rear-wheel-associated cylinder devices (52, 62), with each other, and a shut-off position to shut off the communication between said respective first fluid chambers, with a first cylinder pressure based on respective pressures of respective working fluids in said respective first chambers; and

the second-chamber-associated valve device comprising a second-chamber-associated mechanical valve (230) which is mechanically switched between a communication position to communicate the respective second fluid chambers (76) of the front-wheel-associated and rear-wheel-associated cylinder devices, with each other, and a shut-off position to shut off the communication between said respective second fluid chambers, with a second cylinder pressure based on respective pressures of respective working fluids in said respective second chambers.

19. The system according to claim 18, wherein each of the first-chamber-associated mechanical valve (190) and the second-chamber-associated mechanical valve (230) is normally placed in the communication position thereof and, when a corresponding one of the first and second cylinder pressures exceeds a reference value, the each mechanical valve is switched from the communication position to the shut-off position.

20. The system according to claim 19, wherein said each of the first-chamber-associated mechanical valve (190) and the second-chamber-associated mechanical valve (230) comprises:

a housing (110);

a valve portion (132) including a valve member (128) and a valve seat (126) which comprise

a first movable member (128);

a second movable member (134) which is movable with the first movable member and which is fitted in the housing to divide an inner room of the housing into a first room (160) on the side of the valve portion and a second room (162) opposite to the first room; and

a biasing device (150) which biases the second movable member in a direction in which the valve member is moved away from the valve seat.