Hydraulic bearing

The invention is directed to a hydraulic bearing which includes two connecting pieces, an annular rubber-elastic spring, a hydraulic chamber unit made of a working chamber and a compensating chamber and a partition unit having a connecting channel between the working chamber and the compensating chamber. The partition unit is configured as a disc and is disposed within the vertical elevation of the annular rubber-elastic spring and one of the connecting pieces.

FIELD OF THE INVENTION

The invention relates to a hydraulic bearing with hydraulic damping, which has an annular rubber-elastic spring element, that is, a spring element of an elastomer such as rubber or a plastic with rubber-elastic behavior, as specified for example by DIN 7724. The associated rubber-elastic spring element is connected, on the one hand, to the sprung body and, on the other hand, to the unsprung mass by way of respective upper and lower, likewise annular, connecting pieces, which are generally vulcanized on. If such a hydraulic bearing is used as a chassis spring of a vehicle, one connecting piece is connected to the body as a sprung body, while the other connecting piece is connected to the chassis as an unsprung mass. The hydraulic bearing also comprises a hydraulic chamber unit, which comprises a working chamber and a compensating chamber and is surrounded by the annular spring element and/or the annular connecting pieces in such a way that inward deflection causes the volume of the working chamber filled with a damping medium to change, and further comprises a partition unit provided with at least one connecting channel between the working chamber and the compensating chamber.

BACKGROUND OF THE INVENTION

Springs of the generic type, also known as hydraulic springs, are known in the prior art. For instance, U.S. Pat. No. 3,701,322 discloses a rubber spring with fluid damping for rail vehicles in which two bores are arranged as throttling bores in the partition or damper plate between the working chamber arranged at the bottom and the compensating chamber lying above. When there is inward deflection of the hydraulic springs shown there, the working chamber is reduced in size, as a result of which the fluid in the working chamber is forced through the throttling bores and the resultant dissipation has a damping effect. However, the formation of the throttling bores disadvantageously does not produce any appreciable damping. Rather, such a throttle produces little damping, which moreover only occurs at high frequencies.

U.S. Pat. No. 6,595,504 discloses a hydraulic spring with a damper which has a sufficient damping effect under greatly differing loads and frequencies on account of the relatively long damping channels in the partition unit. Disadvantageously, however, the overall height is relatively great here.

SUMMARY OF THE INVENTION

Therefore, it is an object of the invention to provide a hydraulic bearing, that is, a rubber-elastic spring with hydraulic damping, which provides sufficient and adjustable damping in different frequency and loading ranges and nevertheless only has an overall size that is as small as possible.

The hydraulic bearing of the invention is interposed between a sprung body and an unsprung mass. The hydraulic bearing includes: a lower annular connecting piece connecting the hydraulic bearing to the unsprung mass; an upper annular connecting piece connecting the hydraulic bearing to the sprung body; an annular rubber-elastic spring defining a vertical structural elevation and being connected to the unsprung mass via the lower annular connecting piece and to the sprung body via the upper annular connecting piece; a hydraulic chamber unit including a working chamber and a compensating chamber; the hydraulic chamber unit being surrounded by the annular rubber-elastic spring and/or the annular connecting pieces so as to cause the volume of the working chamber filled with a damping medium to change in response to a deflection of the hydraulic bearing; a partition unit disposed between the working chamber and the compensating chamber; the partition unit including a disc defining a disc plane and the disc having a connecting channel formed in the plane; the annular connecting pieces having respective vertical structural elevations; the partition unit being arranged within the vertical structural elevation of the annular rubber-elastic spring and the vertical structural elevation of one of the annular connecting pieces; the one annular connecting piece having an end facing away from the partition unit; and, the partition unit being disposed within the one annular connecting piece so as to cause the compensating chamber to be configured between the partition unit and the end of the one annular connecting piece.

The partition unit is formed as at least one disc with a connecting channel extending in the plane of the disc and is arranged within the overall vertical elevation of the spring element and a connecting piece, that is, within the extent of the height of these parts in the axis of the spring, that is, the axis along which the spring force acts. At the same time, the partition unit is arranged within the connecting piece in such a way that the compensating chamber is formed between the partition unit and the end of the connecting piece that is remote from the latter.

Such an arrangement of the components and the consequent use of the “inner space” of the spring as a space for further functional elements produce an extremely compact type of construction.

An advantageous feature is that the rubber-elastic spring element is formed as an upwardly open hollow cone, which is connected, on the one hand, to the sprung body and, on the other hand, to the unsprung mass by way of an upper connecting piece, vulcanized on its inner cone, and a lower connecting piece, vulcanized on its outer cone, and in which the partition unit is arranged within the upper connecting piece in such a way that the compensating chamber is formed between the partition unit and the end of the upper connecting piece. The conical form not only has the effect of optimizing the spring properties, it also provides a larger cavity as an “inner structural space” within the components—assuming concentric arrangement—with the same load-bearing capacity of the spring, so that the structural design and production are simplified.

A further advantageous feature is that the connecting piece having the partition unit has a seat or a recess for receiving the partition unit formed as a disc, that is, for example a milled relief or a turned offset. This produces reliable positioning during production and operationally secure fixing.

A further advantageous feature is that the partition unit comprises multiple discs arranged one above the other, the channels of which are connected in such a way that they communicate with one another. This allows the damping to be adapted to different loads and frequencies in an extremely simple way already during production, by way of the overall length of the damping channel connecting the working chamber and the compensating chamber, which is in actual fact provided by the number of discs, that is specifically it is adapted just by adding further discs. This presupposes that the dimensions match and that prepared/pre-milled connecting pieces are available.

A further advantageous feature is that the length of the overall connecting channel formed by multiple discs can be changed by rotating the discs. This either allows the rubber-elastic spring element also to be adapted to changed damping properties under different loads and frequencies after production, or else allows it to be adapted by uniform “standard discs” to different applications just by rotating them during production.

A further advantageous feature is that the connecting channels located in the discs are milled in on one side. This allows the corresponding channels to be produced in a particularly easy and low-cost way. The respective covering of the channels then takes place at least partially by the adjacently lying disc or connecting piece.

A further advantageous feature is that the compensating space is delimited by a cover at the end of the connecting piece. In an improvement of the “open” configuration, which in any case is only possible when the compensating space is formed in the upper connecting piece, the fluid that is used for the damping is particularly well protected against the ingress of foreign bodies or moisture. The same applies to a further advantageous feature, which is that the compensating space is delimited by a membrane arranged within the connecting piece. With such a membrane, which is additionally especially elastic, however, an upside-down type of construction can also be realized, one in which the compensating space is arranged at the bottom.

A further advantageous feature is that the rubber-elastic spring element is formed as a multilayered spring, that is, as a rubber-metal element. This increases the load-bearing capacity of the spring, so that the inward deflection, the changing of the volume of the working chamber and the damping can be designed for particularly high loads, which is particularly necessary for example in the case of rail vehicles, which must absorb load differences of approximately 1:5 between the unloaded state and the loaded state.

The properties of the hydraulic bearing according to the invention with regard to the damping and the overall size can accordingly be used particularly well in the case of a chassis for a rail vehicle. The use of a hydraulic bearing incorporating a rubber-elastic spring element as a machine mounting also offers advantages, since here too the overall size and the damping are the essential properties.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1shows a hydraulic bearing1with hydraulic damping for a chassis of a rail vehicle. The hydraulic bearing comprises an annular rubber-elastic spring element2, which is connected, on the one hand, to the sprung body and, on the other hand, to the unsprung mass by way of respective upper and lower, likewise annular, connecting pieces3and4. The sprung body and the unsprung mass, that is, the body and the chassis of the rail vehicle, are not represented in any more detail here.

The hydraulic bearing1also has a hydraulic chamber unit, which comprises a working chamber5and a compensating chamber6and is surrounded by the annular spring element2and the annular connecting pieces3and4in such a way that inward deflection causes the volume of the working chamber5filled with hydraulic oil as damping medium to change. There is likewise a partition unit8, which is provided with at least one connecting channel7between the working chamber5and the compensating chamber6and is formed as at least one disc9with a connecting channel7extending in the plane of the disc9as shown, for example, inFIG. 4.

The upper connecting piece3has, in this case, a corresponding bore10through which the hydraulic oil can enter the connecting channel7. The disc9is shown seated on thin disc25having an aperture26communicating with connecting bore10formed in the connecting piece3. The connecting channel7is a through slot with a thin disc25defining the base of the channel. The upper connecting piece3is therefore formed as a compact pot-shaped body and can consequently be produced correspondingly easily and accurately.

Inward deflection causes the volume of the working chamber5filled with hydraulic oil as damping medium to change, or be reduced in size, as hydraulic oil flows via the bore10and the connecting channel7out of the working chamber5into the compensating chamber6and produces a damping action caused by the dissipation/fluid friction produced by the flow in the connecting channel7.

The partition unit8is arranged within the overall vertical elevation of the spring element2and the connecting piece3in such a way that the compensating chamber6is formed between the partition unit8and the end11of the connecting piece3that is remote from the partition unit8.

The rubber-elastic spring element2is constructed as a multilayered spring, that is, as a rubber-metal element, and is formed as an upwardly open hollow cone. Accordingly, the rubber parts12, which are reinforced with metal rings13, can be seen inFIGS. 1 to 3.

The rubber-elastic spring element2is connected, on the one hand, to the sprung body and, on the other hand, to the unsprung mass (not shown) by way of the upper connecting piece3, vulcanized on its inner cone, and by way of the lower connecting piece4, vulcanized on its outer cone.

The connecting piece3, which includes the partition unit8, is provided with a seat(s) or a recess(es) for receiving one or more discs9,14and15, which singly or together form the partition unit.FIG. 1shows a hydraulic bearing1, which is provided with one disc9, whileFIG. 2shows a hydraulic bearing21, which is provided with three discs9,14and15.

The partition unit16, consisting of three discs9,14and15, is constructed in such a way that the channels of the discs9,14and15are connected so that they communicate with one another, and consequently provide a long connecting channel17.

The connecting channel17is made up of channel segments in the respective discs (9,14,15) identified inFIG. 5by reference numerals9a,14aand15a. The thick discs9,14and15rest upon respective thin discs27,28and29. The thin discs27,28and29have respective apertures27a,28aand29athrough which the hydraulic oil flows from one channel segment to the next as the hydraulic oil flows from the compensating chamber6to the working chamber5as indicated by the arrows inFIG. 5.

The long connecting channel17allows the damping to be adapted to different loads and frequencies in a very simple manner in the case of both versions shown inFIG. 1andFIG. 2, by way of the overall length of the connecting channel, without changing the connecting piece3. This serves the “same parts principle” in the production of different spring elements.

The three discs9,14and15can be rotated about longitudinal axis32with respect to one another, so that the length of the composite connecting channel17formed by the three channel segments9a,14aand15acan be changed. The thin discs27,28and29are also rotated as shown by comparing their respective positions inFIGS. 5 and 6.

It is also possible to use only two discs, for example the discs9and14, which are rotated to a corresponding length of the connecting channel17and then fixed in order to achieve further adapted damping properties.

The connecting channel segments9a,14aand15alocated here in the thick discs9,14and15are not milled in on one side but are through slots with the apertured thin discs27,28and29sandwiched together with the thick discs. The discs are fixed in the connecting piece3by way of a central threaded fastener18. The single disc9inFIG. 1is likewise a disc having a channel7defined by a through slot and is fixed in the connecting piece3by an outer thin disc19having an aperture to permit the connecting channel7to communicate with the compensating chamber6.

In the exemplary embodiments represented inFIG. 1andFIG. 2, the compensating chamber is upwardly open, while the working chamber5is closed by a cover20at the end of the connecting piece4.

FIG. 3shows a further embodiment of a hydraulic bearing22with a partition unit16consisting of three discs in which the compensating chamber6is delimited by a membrane23arranged within the connecting piece3and is closed by a further cover24. As a compact element that is closed on all sides, the hydraulic bearing22is therefore well protected against the ingress of foreign bodies or moisture and cannot be damaged during transport or installation.

It is also possible to configure the thick disc as shown inFIG. 7wherein the thick disc34is provided with a channel36formed by milling the disc from one side and leaving a channel base38within the disc. The milled channel36ends in an aperture40. The need for a thin disc disposed between mutually adjacent thick discs is thereby obviated.

LIST OF DESIGNATIONS

Part of the Description