EP0486441A1 — A suspension system for vehicles with hydraulic s…

Claim 1

Independent Claim 295 words

A suspension system for vehicles in which two similar, interdependent hydraulic shock absorbers (10; 10a, 10b) interconnect respective remote regions of the suspended part of the vehicle and respective non-suspended parts, in which each shock absorber (10; 10a, 10b) is of the type including a cylinder (14) divided internally into an upper chamber (38; 38a, 38b) and a lower chamber (40; 40a, 40b) by a valved piston (22; 22a, 22b) with a rod (24) which projects from an upper end of the shock absorber, and a compensation chamber (42) which communicates with the lower chamber (40) by means of a valve assembly (34) including a switching servo valve (62; 62a, 62b), and in which the two shock absorbers are interconnected by mutual enslavement means such that, when a predetermined pressure threshold is exceeded in one of the shock absorbers, the servo valve (62; 62a, 62b) of the other shock absorber switches from a state in which the flow of liquid between the lower chamber (40, 40a, 40b) and the compensation chamber (42) through the valve assembly (34) is less restricted to a state in which the flow is more restricted, characterised in that each switching servo valve is a solenoid valve (62; 62a, 62b) and the mutual enslavement means comprise, for each shock absorber (10; 10a, 10b), an electrical pressure transducer (50; 50a, 50b) associated with the upper chamber (38; 38a, 38b) for controlling the solenoid valve of the other shock absorber and for switching the solenoid valve of the other shock absorber from the state in which the flow is less restricted to the state in which the flow is more restricted when the pressure in the upper chamber (38; 38a, 38b) with which the transducer (50; 50a, 50b) is associated exceeds the threshold.

Claim 2

Dependent Claim 295 words

A suspension system for vehicles in which two similar, interdependent hydraulic shock absorbers (10; 10a, 10b) interconnect respective remote regions of the suspended part of the vehicle and respective non-suspended parts, in which each shock absorber (10; 10a, 10b) is of the type including a cylinder (14) divided internally into an upper chamber (38; 38a, 38b) and a lower chamber (40; 40a, 40b) by a valved piston (22; 22a, 22b) with a rod (24) which projects from an upper end of the shock absorber, and a compensation chamber (42) which communicates with the lower chamber (40) by means of a valve assembly (34) including a switching servo valve (62; 62a, 62b), and in which the two shock absorbers are interconnected by mutual enslavement means such that, when a predetermined pressure threshold is exceeded in one of the shock absorbers, the servo valve (62; 62a, 62b) of the other shock absorber switches from a state in which the flow of liquid between the lower chamber (40, 40a, 40b) and the compensation chamber (42) through the valve assembly (34) is less restricted to a state in which the flow is more restricted, characterised in that each switching servo valve is a solenoid valve (62; 62a, 62b) and the mutual enslavement means comprise, for each shock absorber (10; 10a, 10b), an electrical pressure transducer (50; 50a, 50b) associated with the upper chamber (38; 38a, 38b) for controlling the solenoid valve of the other shock absorber and for switching the solenoid valve of the other shock absorber from the state in which the flow is less restricted to the state in which the flow is more restricted when the pressure in the upper chamber (38; 38a, 38b) with which the transducer (50; 50a, 50b) is associated exceeds the threshold.

Claim 3

Dependent Claim 62 words

A suspension system according to Claim 1, characterised in that each transducer (50; 50a, 50b) is a normally-open pressure switch whose closure causes the excitation of a winding (114; 114a, 114b) of the respective solenoid valve (62; 62a, 62b) so that it switches from the state in which the flow is less restricted to that in which the flow is more restricted.

Claim 4

Dependent Claim 57 words

A suspension system according to Claim 2, characterised in that it includes, for each solenoid valve (62; 62a, 62b), a power relay (120a, 120b) with a pair of normally-open contacts (122a, 122b) for supplying the winding (114; 114a, 114b) of the solenoid valve and an excitation winding in series with the respective pressure switch (50; 50a, 50b).

Claim 5

Dependent Claim 46 words

A suspension system according to any one of the preceding claims, characterised in that the normally-open contacts (122a, 122b) of both the relays (120a, 120b) are in parallel with a common switch (124) which can be closed to stiffen both interdependent shock absorbers (10a, 10b) simultaneously.

Claim 6

Dependent Claim 36 words

A suspension system according to Claim 4, for application to a vehicle to counteract pitching, characterised in that the common switch (124) is a contact-maker which is sensitive to the braking or deceleration of the vehicle.

Claim 7

Dependent Claim 60 words

A suspension system according to any one of the preceding claims, characterised in that, in each shock absorber (10; 10a, 10b), the pressure transducer (50) is in the upper end (26) of the rod (24) of the piston (22) and the rod (24) has an axial duct (44) for transmitting pressure from the upper chamber (38) to the transducer (50).

Claim 8

Dependent Claim 107 words

A suspension system according to any one of the preceding claims, characterised in that the solenoid valve (62) is interposed between first and second pressure valve units (60, 64) and is adapted to effect a switch between two paths for the liquid extending hydraulically in parallel between the lower chamber (40) of the cylinder (14) and the compensation chamber (42), one of the paths being less restricted and extending through the first pressure valve unit (60) and a substantially unobstructed duct (80, 84) in the solenoid valve (62) in sequence, and the other being more restricted and extending through both pressure valve units (60, 64) in sequence.

Claim 9

Dependent Claim 166 words

A suspension system according to any one of Claims 1 to 6, in which the shock absorbers (10; 10a, 10b) are of the telescopic type with an annular compensation chamber (42) defined between the cylinder (14) and an outer tube (12), and with a valve assembly (34) at the bottom for communication between the lower chamber (40) of the cylinder (14) and the compensation chamber (42), characterised in that the valve assembly (34) includes a solenoid valve body (68) having a cylindrical diametral valve cavity (78) with ducts (80, 84) which connect the lower chamber (40) to the compensation chamber (42), a cylindrical slide (86) being slidable in the valve cavity (78) and having a rod (88) with an obturator collar (90) for controlling the communication ducts (84) and an end which is associated with the core (111) of an electromagnet slidable in an electromagnet body (102) fixed to the outside of the outer tube (12) and housing a solenoid (114) associated with the core (111).

Claim 10

Dependent Claim 142 words

A suspension system according to Claim 8, characterised in that the valve assembly (34) includes a stack of three bodies, a first, upper one of which is the body (66) of a first pressure valve unit (60), a second, intermediate one of which is the body (68) of the solenoid valve (62) and the third, lower one of which is the body (68) of a second pressure valve unit (62), in that the body (68) of the solenoid valve (62) has holes (82) defining unobstructed communication between the two pressure valve units (60, 64), and in that the connecting ducts (80, 84) are arranged so as to establish substantially unobstructed communication between the first pressure valve unit (60) and the compensation chamber (42), the collar (90) of the slide (86) of the solenoid valve (34) being able to close the ducts (84).

A suspension system for vehicles with hydraulic shock absorbers which are made interdependent to counteract rolling or pitching

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