Vehicle Wheel Suspension with a Hydraulic Vibration Damper

• US 20140217693A1
• Filed: 04/04/2014
• Published: 08/07/2014
• Est. Priority Date: 10/06/2011
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG
• Original Assignee: Bayerische Motoren Werke AG
• Inventors: SCHMIDT, Roland, VOS, Serge, KLEIN, Holger
• Granted Patent: US 9,090,141 B2
• Time in Patent Office: Days
• US Class Current: 280/124.162
• CPC Class Codes: B60G 11/26 having fluid springs only, e.g. hydropneumatic springs B60G11/006, B60G15/12 take precedence
• CPC Class Codes: B60G 11/30 having pressure fluid accumulator therefor, e.g. accumulator arranged in vehicle frame dampers accumulating utilisable energy B60G13/14
• CPC Class Codes: B60G 17/0272 the mechanical spring being a coil spring
• CPC Class Codes: B60G 2202/12 Wound spring
• CPC Class Codes: B60G 2500/30 Height or ground clearance

Abstract

A vehicle wheel suspension is provided having a hydraulic vibration damper, which is connected in parallel to a suspension spring which proportionally supports the vehicle body. A rebound spring is provided, which preferably and typically becomes effective in the event of larger spring deflection distances. The support point of the rebound spring is displaceable in relation to the damper housing by way of a spring support piston, which is provided therein and is displaceable by fluid externally supplied with pressure via pump. In this case, the pump is connected to a pressure accumulator for the fluid and delivers fluid out of the pressure accumulator into the damper housing or out of the damper housing back into the pressure accumulator. The absolute value of the spring constant of the pressure accumulator is at least in the order of magnitude of the spring constant of the associated suspension spring or springs, or is greater.

Claims

1. A vehicle wheel suspension, comprising:

a hydraulic vibration damper connected in parallel to a suspension spring proportionally supporting the vehicle body, the vibration damper including;

a dampening housing;

a rebound spring that first becomes effective in an event of larger spring deflection distances,

a spring support piston provided in the damper housing and being displaceable by fluid externally supplied with pressure by a pump,

a support point of the rebound spring being displaceable in relation to the damper housing of the vibration damper by way of the spring support piston, wherein;

the pump is connected to a pressure accumulator for said fluid and delivers fluid out of said pressure accumulator into the damper housing or out of the damper housing back into the pressure accumulator, and

an absolute value of the spring constant of the pressure accumulator is at least on an order of magnitude of the spring constant of the associated suspension spring or, in the case of multiple suspension springs associated with one pressure accumulator, the spring constants of the multiple suspension springs, or is greater.

2. The vehicle wheel suspension according to claim 1, wherein the spring support piston which delimits a support chamber fillable with said fluid, is held in a starting position, which minimizes a volume of the support chamber, which has essentially ambient pressure, by a spring element, which is supported on the rebound spring.

3. A method of operating a vehicle wheel suspension, the method comprising the acts of:

providing a hydraulic vibration damper connected in parallel to a suspension spring proportionally supporting the vehicle body, the vibration damper including;

a damper housing;

a rebound spring that first becomes effective in an event of larger spring deflection distances;

a spring support piston provided in the damper housing and being displaceable by fluid externally supplied with pressure by a pump, a support point of the rebound spring being displaceable in relation to the damper housing of the vibration damper by way of the spring support piston, wherein the pump is connected to a pressure accumulator for said fluid and delivers fluid out of said pressure accumulator into the damper housing or out of the damper housing back into the pressure accumulator, and an absolute value of the spring constant of the pressure accumulator is at least on an order of magnitude of the spring constant of the associated suspension spring or, in the case of multiple suspension springs associated with one pressure accumulator, the spring constants of the multiple suspension springs, or is greater; and

always setting the support chamber in the damper housing to be substantially free of overpressure by recirculating fluid back into the pressure accumulator via the pump, the support chamber being finable with the fluid.

4. The method according to claim 3, further comprising the act of:

holding the spring support piston delimiting the support chamber in a starting position that minimizes a volume of the support chamber via a spring element supported on the rebound.