Vehicle suspension system

• US 5,088,759 A
• Filed: 05/14/1990
• Issued: 02/18/1992
• Est. Priority Date: 05/17/1989
• Status: Expired due to Term

• Current Assignee: Mazda Motor Corporation
• Original Assignee: Mazda Motor Corporation
• Inventors: Morita, Toshiki, Takehara, Shin
• Primary Examiner(s): Rice, Kenneth R.
• Application Number:
  US07/522,785
• Time in Patent Office: 645 Days
• Field of Search: 280/440, 280/6.1, 280/707, 280/DIG. 1, 188/299, 364/424.25
• US Class Current: 280/5.507
• CPC Class Codes: B60G 17/016 characterised by their responsiveness, when the vehicle is travelling, to specific motion, a specific condition, or driver input B60G17/017 takes precedence
• CPC Class Codes: B60G 2202/154 with an accumulator
• CPC Class Codes: B60G 2204/80 Interactive suspensions; arrangement affecting more than one suspension unit
• CPC Class Codes: B60G 2400/102 vertical
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/41 Steering angle
• CPC Class Codes: B60G 2400/5122 Fluid spring
• CPC Class Codes: B60G 2500/30 Height or ground clearance
• CPC Class Codes: B60G 2600/12 Sampling or average detecting; Addition or substraction
• CPC Class Codes: B60G 2600/14 Differentiating means, i.e. differential control
• CPC Class Codes: B60G 2800/012 Rolling condition
• CPC Class Codes: B60G 2800/014 Pitch; Nose dive
• CPC Class Codes: Y10S 280/01 Load responsive, leveling of vehicle

Abstract

A vehicle suspension system of the disclosure is provided with a cylinder device between a vehicle body member and a vehicle wheel member for the vehicle body member by which suspension characteristics are changed. The suspension characteristics are changed by controlling hydraulic fluid supply for the cylinder device, a vehicle height detecting device for detecting a vehicle height displacement, a vehicle height change rate detecting device for detecting a change rate of the vehicle height displacement, and a control device for receiving signals from both the vehicle height displacement detecting device and the vehicle height change rate detecting device to control the hydraulic fluid supply for the cylinder device. This hydraulic fluid supply is controlled in accordance with a vehicle height change rate gain in a manner that the change rate of the vehicle height displacement is suppressed a gain change device is also provided for changing the vehicle height change rate gain in accordance with a predetermined condition so as to change the control of the hydraulic fluid for the cylinder device. A desirable vehicle height displacement control can therefore, be accomplished.

Claims

1. A vehicle suspension system comprising:

a cylinder device provided between a vehicle body member and a vehicle wheel member for the vehicle body member in which suspension characteristics are changed by controlling hydraulic fluid supplied to the cylinder device,

vehicle height detecting means for detecting a vehicle height displacement,

vehicle height change rate detecting means for detecting a rate at which the vehicle height displacement changes, and

control means for receiving signals from both the vehicle height detecting means and the vehicle height change rate detecting means to determine vehicle height change rate gain coefficients and control the hydraulic fluid supplied tot he cylinder device in accordance with said vehicle height change rate gain coefficients so that the rate at which the vehicle height displacement is changed is suppressed, said control means changing the vehicle height change rate gain coefficients in accordance with a vehicle operating condition so as to change the control of the hydraulic fluid supplied to the cylinder device by increasing at least one of said vehicle height change rate gain coefficients when the vehicle is stopped and starts running.

2. A vehicle suspension system according to claim 1, wherein said control means changes a pitch component of the vehicle height change rate gain coefficients.

3. A vehicle suspension system comprising:

a cylinder device provided between a vehicle body member and a vehicle wheel member for the vehicle body member in which suspension characteristics are changed by controlling hydraulic fluid supplied to the cylinder device,

vehicle height detecting means for detecting a vehicle height displacement,

vehicle height change rate detecting means for detecting a rate at which the vehicle height displacement changes, and

control means for receiving signals from both the vehicle height detecting means and the vehicle height change rate detecting means to determine vehicle height change rate gain coefficients and control the hydraulic fluid supplied to the cylinder device in accordance with said vehicle height change rate gain coefficients so that the rate at which the vehicle height displacement is changed is suppressed, said control means changing the vehicle height change rate gain coefficients in accordance with a vehicle operating condition so as to change the control of the hydraulic fluid supplied to the cylinder device by increasing at least one of said vehicle height change rate gain coefficients when the vehicle is in a braking condition.

4. A vehicle suspension system according to claim 3, wherein said control means changes a pitch component of the vehicle height change rate gain coefficients.

5. A vehicle suspension system comprising:

a cylinder device provided between a vehicle body member and a vehicle wheel member for the vehicle body member in which suspension characteristics are changed by controlling hydraulic fluid supplied to the cylinder device,

vehicle height detecting means for detecting a vehicle height displacement,

vehicle height change rate detecting means for detecting a rate at which the vehicle height displacement changes, and

control means for receiving signals from both the vehicle height detecting means and the vehicle height change rate detecting means to determine vehicle height change rate gain coefficients and control the hydraulic fluid supplied to the cylinder device in accordance with said vehicle height change rate gain coefficients so that the rate at which the vehicle height displacement is changed is suppressed, said control means changing the vehicle height change rate gain coefficients in accordance with a vehicle operating condition so as to change the control of the hydraulic fluid supplied to the cylinder device by increasing at least one of said vehicle height change rate gain coefficients when the vehicle is in a lateral acceleration condition.

6. A vehicle suspension system according to claim 5, wherein said control means changes a roll component of the vehicle height change rate gain coefficients.

7. A vehicle suspension system comprising:

a cylinder device provided between a vehicle body member and a vehicle wheel member for the vehicle body member in which suspension characteristics are changed by controlling hydraulic fluid supplied to the cylinder device,

vehicle height detecting means for detecting a vehicle height displacement,

vehicle height change rate detecting means for detecting a rate at which the vehicle height displacement changes, and

control means for receiving signals from both the vehicle height detecting means and the vehicle height change rate detecting means to determine vehicle height change rate gain coefficients and control the hydraulic fluid supplied to the cylinder device in accordance with said vehicle height change rate gain coefficients so that the rate at which the vehicle height displacement is changed is suppressed, said control means changing the vehicle height change rate gain coefficients in accordance with a vehicle operating condition so as to change the control of the hydraulic fluid supplied to the cylinder device and being separately provided with a pitch control section and a roll control section, a pitch component for a pitch control of the vehicle height change rate gain coefficients being changed by the pitch control section, and a roll component for a roll control of the vehicle height change rate gain coefficients being changed by the roll control section, said pitch component and said roll component being changed independently.

8. A vehicle suspension system according to claim 7, wherein said control means changes the pitch component of the vehicle height change rate gain coefficients.

9. A vehicle suspension system according to claim 7, wherein said control means changes the roll component of the vehicle height change rate gain coefficients.