GB2166516A

GB2166516A - Hydraulically damped rubber mounting

Info

Publication number: GB2166516A
Application number: GB08526825A
Authority: GB
Inventors: Hermann Meindl
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1984-11-02
Filing date: 1985-10-31
Publication date: 1986-05-08
Also published as: GB8526825D0; IT8522621A0; DE3440054A1; FR2572778B1; DE3440054C2; GB2166516B; FR2572778A1; IT1186331B

Abstract

A rubber mounting (1) with a hydraulic damping action, particularly for use as an engine bearing for motor vehicles, has two chambers (14, 17) containing a damping fluid, one chamber (17) having a limiting wall in the form of an elastic rubber spring element (7). The chambers are connected to one another by a throttle (19,18,20) and the mounting further comprises a compensating space (12) separated from the other chamber (14) by a bellows (11). To reduce the overall height of the rubber bearing the compensating space (12) and the chamber (14) which is adjacent thereto are each in the form of an annular space and the two chambers (14, 17) and the compensating space (12) are arranged in tandem in the radial direction of the rubber bearing. <IMAGE>

Description

SPECIFICATION Rubber bearing with a hydraulic damping action The invention relates to a rubber bearing, for example a bearing for an engine mounting in a motor vehicle, the bearing having a hydraulic damping action.

A rubber bearing of this type is known from German Patent Specification 29 06 282. In this rubber bearing two chambers connected to one another by a throttling port are arranged in tandem in the radial direction of the rubber bearing so that the overall height of the rubber bearing can be kept relatively low.

The bellows which defines the outer chamber lies unprotected against the edge of the rubber bearing and is attached by its edges to parts which can execute movements relative to one another.

The problem that the present invention seeks to resolve is to develop the known rubber bearing further in such a manner that, without increasing the axial overall height of the rubber bearing, a compensating means is created which forms a protection for and a means of limiting the deflection of the bellows.

According to the invention, there is provided a rubber bearing with a hydraulic damping action, having two end walls lying opposite one another in an axial direction and at least two chambers containing damping fluid and connected to one another by a throttling port, at least one of which chambers has a limiting wall in the form of an elastic rubber spring element and one of which chambers is in the form of an annular space arranged beside the other chamber in the radial direction of the rubber bearing and defined on the outer side by a bellows which is attached to an inner wall rigidly connected to the spring element, wherein a compensating space, which is separated from the said one chamber in the form of an annular space by the bellows, defines an annular space and is arranged after the two chambers in the radial direction of the rubber bearing, and the compensating space and the chamber which is adjacent thereto lie between a wall and an inner ring which is rigidly connected to said wall, the bellows being braced between the wall and the inner ring.

In the rubber bearing constructed in accordance with the invention, the compensating area lies behind the two chambers in the radial direction of the rubber bearing so that it forms no part of the overall height of the rubber bearing. Also, the parts which delimit the compensating area do not touch the fastening elements of the rubber bearing directly so that the overall height of the bearing can be restricted to the dimension required for fastening. In addition, the bellows is gripped between parts which do not execute any movement relative to one another so that the wall which delimits the compensating area on the outside can be designed in the form of a rigid part which performs well the functions of protecting and limiting the deflection of the bellows.

A rubber bearing is known from German Offenlegungsschrift 30 40 396 in which two chambers and a compensating area are arranged one above the other in the axial direction of the rubber bearing. In this rubber bearing which has a considerable overall height, the compensating area is defined by a bellows and a rigid cover. The provision of a rigid wall of this type to form, together with the bellows, a compensating area is impossible with the subject of German Patent Specification 29 06 282 because in this case they would connect rigidly to one another parts which, as a result of the nature of the rubber bearing, must execute movements relative to one another.

In an advantageous embodiment of the invention, the throttling port which connects the two chambers is in the form of an annular channel in the region of the upper end wall.

In a further embodiment of the invention, an annular diaphragm is inserted with axial play between the two chambers, which diaphragm can be axially loaded and displaced by the damping fluid in the chambers via openings in their limiting walls.

A rubber bearing in accordance with this last embodiment is indicated where a low space requirement exists; such a bearing does not increase the overall height and makes it possible to absorb high-frequency vibrations without a damping response.

An embodiment of the invention will now be described in more detail by way of example and with reference to the accompanying drawing.

A rubber bearing 1, which is shown is cross-section and which serves in this example as an engine bearing for an internal combustion engine (not shown), has an upper retainer 3 rigidly connected to an end wall 2 and a lower retainer 4 in a core 5. An elastic rubber spring element 7 is moulded into the area between the core 5 and an inner ring 6.

The bottom outer edge of the inner ring 6 is rigidly connected, by a steel strip 8, to a wall 9 which is designed to be in one piece with an end wall 2. The annular space between the inner ring 6 and the wall 9 is closed at the top by a channel wall 10 which, on one side, is rigidly connected to the upper inner edge of the inner ring 6 and, on the other side, to the end wall 2 and the wall 9, in their interconnecting area. This annular space is divided by a bellows 11 into a compensating space 12, which is connected to the ambient air by holes 13 in the wall 9, and into an outer chamber 14 adjacent to this compensating area. The bottom rim of the bellows 11 is clamped between the inner ring 6 and the wall 9 and its upper edge is secured between the wall 9 and the channel 10.An inner chamber 17, which is defined by the end wall 2, an end wall 15 of the core 5 and a limiting wall 16 of the spring element 7, is separated from the outer chamber 14 by the channel wall 10 and the inner ring 6.

The two chambers 14 and 17 are filled with damping fluid which can flow from one chamer to another through an annular channel 18 formed by the channel wall 10. For this purpose the annular channel 18 has, at opposite points on the periphery, openings 19, 20 leading into chambers 14, 17, respectively, so that it acts as a throttling port which serves to damp, in particular, low-frequency vibrations having a high amplitude.

To prevent the transmission of high-frequency vibrations of low amplitude, i.e. particularly noise-generated vibrations, an annular diaphragm 22 is fitted loosely between the channel wall 10 and a flange 21 of the inner ring 6, which diaphragm can be loaded and axially deflected by the damping fluid in the chambers 14 and 17 passing through circumferentially distributed holes 23 and 24 in the channel wall 10 and the flange 21. Thus, the rubber bearing according to the invention constitutes, in the area of noise-generated vibrations, a non-rigid bearing arrangement which has a low degree of internal damping or selfdamping and which creates good noise insulation.

The rubber bearing 1 has a very low overall height because this height is determined in the main only by the heights of the inner chamber 17 and spring element 7. On the other hand, the outer chamber 14 and the compensating space 12 do not affect the overall height adversely because, as annular spaces, they enclose the inner chamber 17 and the spring element 7. Also, the annular diaphragm 22 and its bearing arrangement and the annular channel 18 which is arranged radially after this diaphragm and bearing arrangement do not increase the overall height of the rubber bearing 1.

Claims

1. A rubber bearing with a hydraulic damping action, having two end walls lying opposite one another in an axial direction and at least two chambers containing damping fluid and connected to one another by a throttling port, at least one of which chambers has a limiting wall in the form of an elastic rubber spring element and one of which chambers is in the form of an annular space arranged beside the other chamber in the radial direction of the rubber bearing and defined on the outer side by a bellows which is attached to an inner wall rigidly connected to the spring element, wherein a compensating space, which is separated from the said one chamber in the form of an annular space by the bellows, defines an annular space and is arranged after the two chambers in the radial direction of the rubber bearing, and the compensating space and the chamber which is adjacent thereto lie between a wall and an inner ring which is rigidly connected to said wall, the bellows being braced between the wall and the inner ring.

2. A rubber bearing according to Claim 1, wherein the throttling port which connects the two chambers is in the form of an annular channel in the region of the upper end wall.

3. A rubber bearing according to Claim 1 or Claim 2, wherein an annular diaphragm is inserted with axial play between the two chambers, which diaphragm can be axially loaded and displaced by the damping fluid in the chambers via openings in their limiting walls.

4. A rubber bearing having a hydraulic damping action, substantially as hereinbefore described and with reference to the accompanying drawing.