EP0035330A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Vehicle suspension system
Assignee: ZF International UK Ltd
•
Filing: 1981-02-10
•
Granted: —
•
Expires: 2001-02-10
Abstract
Abstract A motor vehicle suspension system comprises four hydro-pneumatic struts (1, 2, 3, 4) three of which (1, 2, 3) are provided with sensors (33, 34, 35) to detect variations in length of the struts. A control system (39) is responsive to the sensors (33, 34, 35) and operates valves (40, 41, 42) to add fluid to or remove fluid from struts (1, 2, 3) to maintain the length of these struts constant. The pressure within the fourth strut (4) is controlled so that the proportion of the static roll-torque (caused by off-centre loading of the vehicle) which is reacted by the front and rear axles is the same as the proportion of the static weight of the vehicle which is reacted by the front and rear axles respectively. Control of the pressure within the fourth strut (4) is accomplished by a control valve (14) having a valve spool which is subject to the pressures within the four struts (1, 2, 3, 4).
Inventors
- 👤 Peter William Brown
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 18:43
CPC Classifications
B; B60; B60G; B60G17/00; B60G17/02; B60G17/033; B60G17/015; B60G17/0152; B60G17/016; B60G21/00; B60G21/02; B60G21/06; B60G2202/00; B60G2202/10; B60G2202/15; B60G2204/00; B60G2204/80; B60G2400/00; B60G2400/25; B60G2400/252; B60G2500/00; B60G2500/30; B60G2600/00; B60G2600/02; B60G2800/00; B60G2800/01; B60G2800/012; B60G2800/019
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
227 words
A vehicle suspension system for a vehicle having four ground engaging wheels and a variable length suspension strut for each of said ground engaging wheels, characterised in that the system comprises detector means (33,34,35) for detecting departure of the vehicle body from a datum zone which is fixed relative to a datum plane defined by three points on the unsprung portions of the vehicle suspension; means (39,40,41,42) responsive to said detector means (33,34,35) for controlling the effective length of three (1,2,3) of said struts to restore the vehicle body to the datum zone; and means (14) for adjusting the force exerted by the fourth strut (4) to such a value that for any loading of the vehicle the ground reaction of the wheel (32) associated with the fourth strut satisfies the condition: where R 4 = ground reaction of the wheel (32) associated with the fourth strut (4) R 3 = ground reaction of the other wheel (31) at the same end of the vehicle as the wheel (32) associated with the fourth strut (4) R 2 = ground reaction of the other wheel (30) at the same side of the vehicle as the wheel (32) associated with the fourth strut (4) R 1 = ground reaction of the wheel (29) diametrically opposed to the wheel (32) associated with the fourth strut (4) k = a constant.
Claim 2
Dependent Claim
227 words
A vehicle suspension system for a vehicle having four ground engaging wheels and a variable length suspension strut for each of said ground engaging wheels, characterised in that the system comprises detector means (33,34,35) for detecting departure of the vehicle body from a datum zone which is fixed relative to a datum plane defined by three points on the unsprung portions of the vehicle suspension; means (39,40,41,42) responsive to said detector means (33,34,35) for controlling the effective length of three (1,2,3) of said struts to restore the vehicle body to the datum zone; and means (14) for adjusting the force exerted by the fourth strut (4) to such a value that for any loading of the vehicle the ground reaction of the wheel (32) associated with the fourth strut satisfies the condition: where R 4 = ground reaction of the wheel (32) associated with the fourth strut (4) R 3 = ground reaction of the other wheel (31) at the same end of the vehicle as the wheel (32) associated with the fourth strut (4) R 2 = ground reaction of the other wheel (30) at the same side of the vehicle as the wheel (32) associated with the fourth strut (4) R 1 = ground reaction of the wheel (29) diametrically opposed to the wheel (32) associated with the fourth strut (4) k = a constant.
Claim 3
Dependent Claim
50 words
20 A vehicle suspension system according to claim 1 characterised in that the constant (k) is such that the distribution of static roll-torque between the front and rear axles of the vehicle is in substantially the same ratio as the distribution of static weight between the front and rear axles.
Claim 4
Dependent Claim
34 words
A vehicle suspension system according to claim 2 characterised in that substantially 60% of the static weight of the vehicle and of the static roll-torque is supported by the front axle of the vehicle.
Claim 5
Dependent Claim
103 words
A vehicle suspension system according to any preceding claim characterised in that the detector means (33,34,35) comprises a respective detector (33,34,35) for each of the said three struts (1,2,3), each detector (33,34,35) being operative to emit a signal when the effective length of its associated strut (1,2,3) lies outside a predetermined range, and wherein the means (39,40,41,42) for controlling the effective length of the said three struts (1,2,3) comprises means (40,41,42) operative in response to signals emitted by the said detectors (33,34,35) for returning the effective length of each strut (1,2,3) to a value lying within the said predetermined range for that strut.
Claim 6
Dependent Claim
20 words
A vehicle suspension system according to any preceding claim characterised in that the suspension struts (1,2,3,4) are each hydro-pneumatic struts.
Claim 7
Dependent Claim
51 words
A vehicle suspension system according to claim 5 characterised in that the means (14) for adjusting the force exerted by the fourth strut (4) comprises means (14) for setting the fluid pressure within the fourth strut (4) to a value determined by the fluid pressure within the three remaining struts (1,2,3).
Claim 8
Dependent Claim
135 words
A vehicle suspension system according to claim 6 characterised in that the means (14) for adjusting the force exerted by the fourth strut (4) comprises: a valve having a valve body (17) in which is slidably mounted a valve spool (18), the valve spool (18) being biased in one direction by the pressure subsisting within the fourth strut (4) and by the pressure subsisting within the strut (1) diametrically opposed on the vehicle to the fourth strut (4) and being biased in the opposite direction by the pressure subsisting within the two remaining struts (2 and 3); and means (39) responsive to movement of the valve spool (18) as a result of imbalance of forces due to the fluid pressures acting thereon to change the pressure within the fourth strut (4) to correct said imbalance.
Claim 9
Dependent Claim
170 words
A control valve for use in controlling the fluid pressure within the fourth strut of a four strut hydro-pneumatic vehicle suspension system in response to the pressures subsisting within the other three struts, characterised in that the valve comprises: a valve body (17) defining first and second cylinders; first and second pistons (19 and 20) slidably and sealingly mounted in the first and second cylinders respectively, the first piston (19) dividing the first cylinder into first and second chambers (11 and 13), and the second piston dividing the second cylinder into third and fourth chambers (12 and 16); a common piston rod (25) connecting the pistons (19,20) and extending through the second and fourth chambers (13 and 16); means (8,9,10,15) for applying the fluid pressure subsisting within each of the struts (1,2,3,4) to a respective one of the chambers (11,12,13,16); and indicating means (26,27,28) for indicating movement of the piston rod (25) due to imbalance of forces on the pistons (19,20) caused by the fluid pressure within the chambers (11,12,13,16).
Claim 10
Dependent Claim
170 words
A control valve for use in controlling the fluid pressure within the fourth strut of a four strut hydro-pneumatic vehicle suspension system in response to the pressures subsisting within the other three struts, characterised in that the valve comprises: a valve body (17) defining first and second cylinders; first and second pistons (19 and 20) slidably and sealingly mounted in the first and second cylinders respectively, the first piston (19) dividing the first cylinder into first and second chambers (11 and 13), and the second piston dividing the second cylinder into third and fourth chambers (12 and 16); a common piston rod (25) connecting the pistons (19,20) and extending through the second and fourth chambers (13 and 16); means (8,9,10,15) for applying the fluid pressure subsisting within each of the struts (1,2,3,4) to a respective one of the chambers (11,12,13,16); and indicating means (26,27,28) for indicating movement of the piston rod (25) due to imbalance of forces on the pistons (19,20) caused by the fluid pressure within the chambers (11,12,13,16).
Claim 11
Dependent Claim
70 words
A control valve according to claim 8 characterised in that the indicating means (26,27,28) is operative to produce a first signal in response to movement of the piston rod (25) in one direction beyond a first predetermined position and to produce a second signal in response to movement of the piston rod (25) in the opposite direction beyond a second predetermined position which is offset from the first predetermined position.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.