Self-leveling vehicle suspension system

• US 3,992,039 A
• Filed: 10/08/1975
• Issued: 11/16/1976
• Est. Priority Date: 10/14/1974
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Hiruma, Mituo
• Primary Examiner(s): Goodman, Philip
• Application Number:
  US05/620,841
• Time in Patent Office: 405 Days
• Field of Search: 280/703, 280/104, 280/708, 280/6 H, 267/64, 267/65 D
• US Class Current: 280/5.513
• CPC Class Codes: B60G 17/005 Suspension locking arrangements for retractable wheels B62D61/12
• CPC Class Codes: B60G 17/0152 characterised by the action on a particular type of suspension unit B60G17/01941 takes precedence
• CPC Class Codes: B60G 17/033 characterised by regulating means acting on more than one spring
• CPC Class Codes: B60G 21/0556 including a releasable coupling B60G21/0555 takes precedence

Abstract

A self-levelling vehicle suspension system is provided with a vehicle body position control device which restrains a stabilizer bar of the suspension system from turning and twisting about its axis during acceleration or deceleration in which the vehicle body tends to pitch due to rearward or forward weight transfer that causes the front end of the body to lower or lift, the device comprising a suspension control unit connected to the stabilizer bar and arranged to operate in a hydromechanical, electromechanical or hydroelectrical fashion responsive to acceleration or deceleration of the vehicle.

Claims

1. In a self-levelling suspension system of an automotive vehicle with at least one set of cooperative road wheels and including suspension members respectively connected to said road wheels, a lateral stabilizer bar connected between said suspension members and rotatable about its axis as the road wheels are caused to vertically move relative to the body structure of the vehicle and a hydropneumatically-operated self-levelling strut connected between the vehicle body structure and each of said suspension members, a vehicle body position control device for locking said stabilizer bar relative to the vehicle body structure during acceleration or deceleration of the vehicle, said device comprising a suspension control unit comprising a cylinder axially movable relative to the vehicle body structure, a piston axially movable in said cylinder, an elongated connecting member fixedly connected at one end to said piston and pivotally connected at the other end to said stabilizer bar, biasing means urging said piston into a predetermined equilibrium position in said cylinder and locking means having a first condition allowing said cylinder to axially move relative to the vehicle body structure and a second condition holding the cylinder locked relative to the vehicle body structure, and control means responsive to the rate of change of the cruising velocity of the vehicle and operative to hold said locking means in said first condition thereof when the rate of change of the vehicle velocity is within a predetermined range and to actuate said locking means into said second condition thereof when the rate of change of the vehicle velocity is outside said predetermined range.

2. A vehicle body position control device as claimed in claim 1, in which said locking means comprise a braking member having a first position disengaged from said cylinder and a second position in braking engagement with said cylinder for locking the cylinder relative to the vehicle body structure, and fluid-operated actuating means biased to hold said braking member in said first position thereof and operative to force the braking member into said second position thereof when operated by fluid, said control means comprising an electric control circuit operative to produce an electric signal when the rate of change of the cruising velocity of the vehicle is outside said predetermined range and solenoid-operated valve means actuated by said signal for providing fluid communication between said fluid-operated actuating means and a source of working fluid so that the actuating means is operated to actuate said braking member into said second position thereof.

3. A vehicle body position control device as claimed in claim 2, in which said braking member consists of a friction band located around said cylinder and having opposite end portions connected to said fluid-operated actuating means, said friction band being expanded over said cylinder when held in said first position thereof and contracted on said cylinder when actuated into said second position thereof.

4. A vehicle body position control device as claimed in claim 3, in which said fluid-operated actuating means comprise a cylinder stationary relative to the vehicle body structure, a piston axially movable in said cylinder and defining in said cylinder of the actuating means a pressurized fluid chamber which is in communication with said source of working fluid over said valve means, a piston rod longitudinally projecting outwardly of the cylinder of the locking means from said piston of the locking means, one of said opposite end portions of said friction band being fixedly connected to said cylinder of the locking means and the other of the opposite end portions being fixedly connected to said piston rod for being moved toward and away from the former end portion as said piston of the locking means is longitudinally moved in said cylinder of the locking means, and biasing means for urging said opposite end portions of said friction band away from each other.

5. A vehicle body position control device as claimed in claim 3, further comprising a housing stationary relative to the vehicle body structure and longitudinally slidably receiving said cylinder therein, said housing having formed in an inner peripheral wall thereof a circumferential groove receiving said friction band therein.

6. A vehicle body position control device as claimed in claim 5, in which said circumferential groove is formed in a longitudinally middle portion of said inner peripheral wall of said housing.

7. A vehicle body position control device as claimed in claim 1, in which said locking means comprises a plurality of substantially equidistantly spaced circumferential grooves formed in an outer peripheral wall of said cylinder and a solenoid-operated plunger unit stationary relative to the vehicle body structure and including a plunger movable between a first position disengaged from said cylinder and a second position engageable with the cylinder through one of said circumferential grooves, said control means being electrically connected to said solenoid-operated plunger unit and operative to produce an output signal when the rate of change of the cruising velocity of the vehicle is outside said predetermined range, said plunger unit being operative to have its plunger moved into said second position thereof in response to said output signal from said control means.

8. A vehicle body position control device as claimed in claim 7, further comprising a housing stationary relative to the vehicle body structure and axially slidably receiving said cylinder therein, said housing having formed in a longitudinal wall thereof a hole through which said plunger is movable between said first and second positions thereof.

9. A vehicle body position control device as claimed in claim 8, in which said hole is formed in a longitudinally middle portion of said wall portion of the housing.

10. A vehicle body position control device as claimed in claim 1, further comprising a housing stationary relative to the vehicle body structure and axially slidably receiving said cylinder therein for providing therein first and second chambers across said cylinder, said locking means comprising passage means for providing communication between said first and second chambers in said housing, a body of incompressible fluid in said first and second chambers and said passage means, and solenoid-operated valve means stationary relative to the vehicle body structure and having a first condition allowing said passage means to open and a second condition closing said passage means for blocking communication between said first and second chambers in the housing, said control means being electrically connected to said solenoid-operated valve means and operative to produce an output signal when the rate of change of the cruising velocity of the vehicle is outside said predetermined range, said valve means being actuated into said second condition thereof in response to said output signal from said control means.

11. A vehicle body position control device as claimed in claim 10, in which said passage means comprises a passageway formed in a longitudinal wall portion of said housing.

12. A vehicle body position control device as claimed in claim 11, in which said housing is formed with a hole in said longitudinal wall portion thereof and in which said valve means have a valve element movable through said hole between a first position retracted from said passageway and a second position projecting into said passageway for closing the passageway.

13. A vehicle body position control device as claimed in claim 1, in which said cylinder has opposite end walls and in which said biasing means comprise first and second preload springs each of which is seated at one end on each of the end faces of said piston and each of said opposite end walls of said cylinder.

14. A vehicle body position control device as claimed in claim 1, further comprising a housing stationary relative to the vehicle body structure and axially receiving said cylinder therein.

15. A vehicle body position control device as claimed in claim 14, in which said housing has opposite end walls formed with respective apertures substantially in line with each other, said connecting member longitudinally passed through the aperture in one of said end walls of said housing.

16. A vehicle body position control device as claimed in claim 15, further comprising a guide rod projecting from said piston and longitudinally movably passed through the aperture in the other of said end walls of said housing.

17. A vehicle body position control device as claimed in claim 1, in which said control means comprise an electric control circuit comprising signal generating means responsive to the rate of change of the cruising velocity of the vehicle and operative to produce an output signal when the rate of change of the vehicle velocity is outside said predetermined range, a delay circuit connected to said signal generating means for passing said output signal after a predetermined interval the signal is delivered to the delay circuit, and switch means operative to actuate said locking means into said second condition thereof when triggered by the output signal passed through said delay circuit.