Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2001-07-18
2003-03-04
Schwartz, Christopher P. (Department: 3683)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
C267S140120, C267S293000
Reexamination Certificate
active
06527261
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a hydraulically damping elastomeric bearing suitable for mountings in a motor vehicle.
BACKGROUND INFORMATION
German Published Patent Application No. 38 21 240 describes an elastomeric bearing, in which an elastic connecting body, for example, made of an elastic or elastomeric plastic or rubber, is arranged between a sleeve-shaped outer first bearing component and an inner second bearing component coaxial to the latter. With the aid of this connecting body, an elastic connection between the first bearing component and the second bearing component is made, which allows relative movements between the bearing components. The conventional elastomeric bearing also includes two chambers which are filled with a liquid damping medium and communicate with one another via a throttle duct. Elastomeric bearings of this type are used in order to mount a vibrating assembly on a non-vibrating holding device. The elastomeric bearings serve, in this context, for vibration insulation or vibration damping. For example, elastomeric bearings of this type are used in vehicle construction, in order to mount vehicle axles, a transmission or an engine on the vehicle body. In this case, one of the bearing components is connected to the vibrating assembly, while the other bearing component is coupled to the non-vibrating holding device. The vibrations of the assembly result in relative movements between the bearing components which reduce the volume of one chamber and at the same time increase the volume of the other chamber. In this case, the liquid damping medium is exchanged correspondingly between the chambers via the throttle duct. The throttling action of the throttle duct results, under these circumstances, in a damping of the relative movement and therefore in a damping of the vibrations capable of being transmitted between the sleeves.
The vibrations to be damped by an elastomeric bearing may have different characteristics, depending on the application. For example, in an elastomeric bearing which is installed in a motor vehicle, vibrations of low frequency and high amplitude, such as, for example, engine shaking vibrations and idling vibrations, may occur, and even high-frequency vibrations of low amplitude which result, for example, in a drumming noise within a passenger compartment of the motor vehicle. The abovementioned German Published Patent Application No. 38 21 240 describes an elastomeric bearing which sufficiently damps both vibrations of low frequency and high amplitude and vibrations of high frequency and low amplitude.
In another application, it may, for example, be necessary to design the elastomeric bearing so that smaller relative movements between the bearing components are damped to a greater extent than larger relative movements. For example, by an elastomeric bearing which is installed in a vehicle, vibrations generated by the vehicle engine are to be damped to a greater extent than vibrations which are caused during the braking or acceleration of the vehicle or by road unevennesses.
It is an object of the present invention to provide an elastomeric bearing that has a different damping behavior for relatively small relative movements between the bearing components from that for relatively large relative movements.
SUMMARY
The above and other beneficial objects of the present invention are achieved by providing an elastomeric bearing as described herein. In one example embodiment of the present invention, two chambers of the elastomeric bearing are connected to one another via at least two throttle ducts, one throttle duct containing an absorber which controls the passage or opening cross-section of the other throttle duct. The absorber is mounted in the first throttle duct so as to be adjustable in the longitudinal direction of the throttle duct, the absorber being adjusted as a function of pressure differences at the ends of the first throttle duct and therefore as a function of pressure differences between the chambers connected by the first throttle duct. Pressure differences between the chambers are generated by relative movements between the bearing components. Relative movements between the bearing components correspondingly result in adjustment movements of the absorber. On account of the absorber mass, a specific damping action is thus obtained.
The absorber may, for example, cooperate with the second throttle duct so that, in the case of relatively small relative movements between the bearing components, the absorber blocks the passage cross-section of the second throttle duct, so that the latter does not allow any exchange of damping medium between the chambers. Only when larger relative adjustments occur between the bearing components does the absorber control the passage cross-section of the second throttle duct so that the latter opens to a greater or lesser extent. Correspondingly, in the case of larger relative movements, an exchange of damping medium between the chambers may occur to a greater or lesser extent through the second throttle duct. The result of this is that the elastomeric bearing therefore has a different damping action in the case of larger relative movements between its bearing components from that in the case of smaller relative movements.
In an example embodiment of the present invention, the absorber frees the opening cross-section of the second throttle duct to a greater or lesser extent in the case of smaller relative movements and closes it only in the case of larger relative movements.
The second throttle duct may include a first inlet orifice assigned to the first chamber and a first outlet orifice assigned to the second chamber, the first inlet orifice being connected to the first throttle duct and being controlled by the absorber. By virtue of this arrangement, the control of the inlet orifice or opening cross-section of the inlet orifice may be implemented in a particularly simple manner, since the inlet orifice to be controlled is arranged in the vicinity of the absorber.
The second throttle duct may also include a second inlet orifice assigned to the second chamber and a second outlet orifice assigned to the first chamber, the second inlet orifice being connected to the first throttle duct and being controlled by the absorber. A relatively simple configuration is obtained because of the vicinity of the absorber to the second inlet orifice. In addition, the absorber or the control of the absorber may be configured so that the absorber keeps the first inlet orifice open and the second inlet orifice closed in the case of a sufficient excess pressure in the first chamber and keeps the first inlet orifice closed and the second inlet orifice open in the case of a sufficient excess pressure in the second chamber. In addition, the first outlet orifice may include a first non-return valve which blocks a flow through the second throttle duct from the first outlet orifice to the first inlet orifice and allows a flow from the first inlet orifice to the first outlet orifice. Moreover, the second outlet orifice may include a second non-return valve which blocks a flow through the second throttle duct from the second outlet orifice to the second inlet orifice and allows a flow from the second inlet orifice to the second outlet orifice. The selected alternate control of the two inlet orifices by the absorber and the selected arrangement of the non-return valves ensure that the flow may pass through the second throttle duct in both directions, the control of the throughflow cross-section being implemented by the absorber simultaneously for both directions of throughflow. A form of construction of this type may be made highly compact.
Alternatively, in an example embodiment of the present invention, the first throttle duct includes the absorber, the second throttle duct includes a first inlet orifice assigned to the first chamber and a first outlet orifice assigned to the second chamber, the first inlet orifice being connected to the first throttle duct and being controlled by the absorber,
Breitfeld Thorsten
Hettich Klaus-Thomas
Koeder Bernd
Daimler-Chrysler AG
Kenyon & Kenyon
Kramer Devon
Schwartz Christopher P.
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