GB1583965A - Vibration absorbing mountings for machines - Google Patents

Description

PATENT SPECIFICATION ( 11) 1583965

( 21) Application No 44377/79 ( 62) Divided out of No 1 583 963 ( 31) Convention Application Nos.

( 22) Filed 26 April 1977 ( 19) 2618333 2 647 105 2 648 526 2718 121 21 711 C n R ( 32) Filed 27 April 1976 19 Oct 1976 27 Oct 1976 23 March 1977 71 A Ms 1 W 77 inhe i-U- 4 v,, / / ill 1 ( 33) Fed Rep of Germany (DE) ( 44) Complete Specification published 4 Feb 1981 ( 51) INT CL 3 F 16 F 13/00 ( 52) Index at acceptance F 2 S 101 410 411 AA ( 72) Inventors HEINZ BRENNER and ARNO HAMAEKERS ( 54) VIBRATION ABSORBING MOUNTINGS FOR MACHINES ( 71) We, BOGE Gmb H, a German Company of 5208 Eitorf, Western Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:-

This invention relates to a resilient coupling for resiliently connecting two components movable relative to each other in particular, though not exclusively, to a coupling which is suitable for mounting a motor vehicle engine.

In engine couplings having resilient side walls the spring characteristics of the engine suspension can be set in an optimum manner by appropriate design of the coupling and choice of the quality of rubber and at the same time the damping provided by the hysteresis of the rubber walls can be added to hydraulic damping by appropriate design so that also for the oscillation damping of the engine suspension the relationships are an optimum It is also possible to fulfil the requirement of motor vehicle construction that the low-frequency large-amplitude oscillations of the engine are heavily damped and the high frequency vibrations of small amplitude, for example 0 1 mm, of the engine are transmitted, as far as possible, undamped.

A hollow liquid spring with built-in damping is known The spring having a main chamber and an expansion chamber which are filled with a liquid medium and are connected together through openings in an intermediate wall that serves as a mounting bracket, the main chamber comprising a hollow spring body of resilient rubber material and the expansion chamber being defined by a rubber diaphragm In this known arrangement the expansion chamber has the sole function of accepting fluid forced out of the main chamber and of returning it to the main chamber, the resilient deformation of the diaphragm assisting in the springing action-only to a minimal extent A drawback in this known arrangement is that the space taken up by the expansion chamber is not available for the main function of the coupling, namely the springing function.

According to the present invention we provide a resilient coupling for resiliently connecting two components movable relative to each other, the couling being in the form of a hollow body which in use of the coupling contains a hydraulic damping fluid, and the interior of the body being divided by partition means of the coupling into main and auxiliary chambers between which a restricted flow of fluid can take place upon relative movement between said two components, the coupling comprising first mounting means to which one of the components can be secured and which comprises two end portions of the hollow body which are spaced apart and fixed relative to each other, second mounting means to which the other of the components can be secured and which is of an annular form and is positioned generally between said two end portions, and resilient wall means which connects said first and second mounting means and comprises resilient annular wall portions which connect said second mounting means with said end portions, said partition means comprising a movable portion arranged to move to accommodate small variations in the volumes of the main and auxiliary chambers so that the coupling can accommodate vibrations of small amplitude without hydraulic damping.

In a coupling according to the present invention the space of the auxiliary chamber is employed not only for the damping function, by accepting and returning, the fluid forced out of the main chamber, but also for the springing function.

The movable portion of the partition means is preferably of a generally annular form providing a central aperture for the passage of fluid between the main and auxiliary chambers The movable portion may comprise a radially outer portion, and a radially 1,583,965 inner portion which is axially thinner than said outer portion and is positioned axially centrally of said outer portion.

The movable portion of the partition means may be arranged to provide different resistances to the flow of fluid through an aperture therein in opposite directions between the main and auxiliary chambers In one preferred arrangement an inner portion of the movable portion is of a resilient material and is arranged to be deflected axially of an outer portion by a difference between the fluid pressures in the main and auxiliary chambers, the inner portion being shaped so that resistance to the flow of fluid through the aperture in the movable portion is varied by deflection of the inner portion A radially inner peripheral surface of the inner portion, bounding the aperture in the movable portion of the partition means, can with advantage be of a convex curved shape as viewed in axial cross-section.

The movable portion of the partition means can conveniently be in the form of an annular body which is axially movable between two extreme positions determined by engagement of the movable portion with annular shoulders which bound an annular groove in a dividing wall portion of the partition means Alternatively, the movable portion may comprise radially outwardly projecting end flanges arranged to engage the dividing wall portion to determine the extreme positions of movement of the movable portion In either arrangement an annular gap between the annular portion and the dividing wall portion can provide a passage for the flow of fluid between the chambers.

In a further alternative arrangement the movable portion is secured to a dividing wall portion of the partition means by means of a resilient annular connecting portion which extends radially between the movable portion and the dividing wall portion and permits limited axial movement of the movable portion relative to the dividing wall portion.

A spacing member may extend between the end portions of the coupling and extend through an aperture in the movable portion of the partition means, so defining with the movable portion an annular passage through which a restricted flow of fluid can pass between the chambers.

There is described and claimed in copending Patent Application No 17279/77 (Serial No 1,583,963), from which the present Application is divided, a resilient coupling for resiliently connecting two components movable relative to each other, the coupling being in the form of a hollow body which in use of the coupling contains a hydraulic damping fluid, and the interior of the body being divided into main and auxiliary chambers between which a restricted flow of fluid can take place upon relative movement between said two components, the coupling comprising first mounting means to which one of the components can be secured and which comprises two end portions of the hollow body which are spaced apart and fixed relative to 70 each other, second mounting means to which the other of the components can be secured and which is of an annular form and is positioned generally between said two end portions, and resilient wall means which con 75 nects said first and second mounting means and comprises resilient annular wall portions which connect said second mounting means with said end portions, at least one of said end portions engaging the associated annular 80 wall portion over a frusto-conical surface.

Some embodiments of couplings according to the invention are illustrated, by way of example only, in the accompanying drawings wherein: 85 Figure 1 shows an axial cross-section through a first ebodiment; Figure 2 shows an axial cross-section through a second embodiment; and Figure 3 is a scrap view showing a modifi 90 cation of the first embodiment to provide the third embodiment.

Referring to the accompanying drawings, each of the resilient couplings illustrated is suitable for mounting an engine (not shown) 95 to an engine carrying sub-frame In general each coupling is in the form of a hollow body 1 defined by end portions, comprising end plates 2, 3, provided by first mounting means which is adapted to be connected to the 100 engine, and by resilient wall means 4 The end portions of the body are spaced apart and fixed relative to each other Each coupling includes partition means 5 dividing the interior of the body into a main fluid chamber 6 and 105 an auxiliary fluid chamber 7, fluid control means for controlling a restricted flow of fluid between the chambers, and annular second mounting means 9 (positioned generally between the two end portions of the body 1) 110 adapted to be connected to the engine carrying sub-frame and being connected to the first mounting means by the wall means 4 The main fluid chamber 6 and auxiliary fluid chamber 7 are filled with damping liquid 115 which is preferably made of 50 % water and % glycol.

In the first embodiment, shown in Figure 1, the end plates 2, 3 are spaced apart by means of a through bolt 150 having shoulders -151, 120 152 The end plate 2 engages the shoulder 151 and is secured in position by a disc-shaped element 153, a mounting bracket 10 of the first mounting means, and a nut 12 The end plate 3 engages the shoulder 152 and is 125 secured in position by a nut 154 The resilient wall means 4 and a dividing wall portion of the partition means 5 are provided by a single body 73, of a resilient rubber material The outer peripheral portion of one end of the 130 component is adhesively bonded to an inner frusto-conical surface of a metal ring 76 secured to the end plate 2, and the outer peripheral portion of the other end is adhesively bonded to an inner surface of a metal ring 79 secured to the end plate 3 A frusto'-conical flange 80 formed by pressing' from a sheet metal component 81 is embedded in and adhesively bonded to the central portion of the rubber component 73 The sheet metal component 81 forms a mounting bracket of the second mounting means 9 The rings 76 and 79 are sealingly connected to the end plates 2, 3 respectively by rolling the inner edges'of the rings over the periphery of the associated end plate.

The partition means 5 is formed with an annular shoulder 155 which together with an annular shoulder provided by a disc-shaped insert 157 defines a channel-shaped groove 158 in the dividing wall portion of the partition means The fluid control means comprises a movable'portion of the partition means in the form of a resilient annular body 159 having the shape shown and made for example from rubber The body 159 is located in the groove 158 and has a central aperture 160 through which the bolt 150 extends The body 159 comprises a radially outer portion in the form of an annular rubber ring 159 a, and a radially inner portion in the form of an intermediate wall 159 b of reduced axial thickness The wall 159 b is positioned axially centrally of ring 159 a The body 159 can move axially relative to the bolt and the dividing wall portion of the partition means between two extreme positions, in one of which the body engages the shoulder 155, in the other of which the body engages the insert 157, to accommodate small variations in the volumes of the main and auxiliary chambers An annular gap 161 is defined between the outer peripheral surface of the body 159 and the groove 158 and an annular gap defining a throttling restriction 162 is defined between the outer surface of the bolt and a radially inner peripheral surface 163 of the body bounding the aperture 160 The surface 163 is of a convex curved shape in axial cross-section and provides a bight 164 at the centre of the aperture 160 The intermediate wall 159 b is relatively easily deformable.

The main chamber 6 and the auxiliary chamber 7 are filled with hydraulic fluid and communicate with one another through the throttling restriction 162 In the position of the body 159 illustrated there is a further communication between the chambers through the gap 161.

The displacement surface area of the body 159, effective in the axial direction, multiplied by the total distance which the body can move in either direction, equivalent to (x+y), determines a maximum volume displacement of the body 159 In the event of very small amplitude oscillations of the end plates 2 and 3 with respect to a mounting bracket 82 (of the second mounting means 9) in an axial direction, in which the changes in volume in 70 the chambers 6 and 7 does not exceed the displacement volume of the body 159, the body 159 oscillates back and forth between the shoulder 155 and the insert 157 and no exchange of fluid takes place between the 75 chambers i e there is no hydraulic damping of the oscillations of the engine mounting On larger amplitudes of oscillation with changes in volume in the chambers which exceed the displacement volume of the body 159, fluid is 80 forced through the throttling restriction 162 according to the prevailing engagement, determined by flow, of the body 159 against the shoulder 155 or the insert 157 The quantity of fluid flowing through the throttling 85 restriction 162 is the greater, the greater is the oscillatory travel remaining after the body 159 has engaged the shoulder 1 S Sor the 'insert 157, and a pressure difference is produced between the chambers 6 and 7 through the resis 90 tance of the throttling restriction 162, the velocity of flow for a given quantity being determined by the cross-section of the restriction 162 and the flow factor of the restriction 162, itself determined by the profile of the portion 95 163.

In the position of the body 159 illustrated, the portion 163 produces -a nozzle-shaped inlet for flow and a nozzel-shaped outlet When the wall 159 b of the body 159 is deflected axially 100 of the ring 159 a by a correspondingly large pressure difference between the chambers 6 and 7, both the cross-section for flow and above all also the flow factor of the restriction 162 changes in that the inlet no longer re 105 mains nozzle-shaped but is formed by a sharp edge As compared with a fixed profile for the portion 163, this results in a sharp rise of the resistance to flow of the restriction 162.

By appropriate shaping of the portion 163 110 one can also achieve the result that the resistance to flow increases more slowly, especially when, with increasing deflection of the wall 159 b, a cross-section of the restriction 162 increases in a decisive manner The flow 115 relationship of the arrangement shown can be influenced by an additional control function of the body 159, for example, by the provision of openings in the insert 157 which remain open allowing flow of fluid through the gap 120 161 when the body 159 engages the insert 157.

The resistance to flowicanfurthermore be made of different magnitudes according to the direction of flow; in the present case the resistance would be smaller on the flow out of the 125 main chamber 6 into the auxiliary chamber 7 than when the main chamber 6 is being filled from the auxiliary chamber 7.

Figure 2 shows a coupling similar to the coupling shown in Figure 1 but incorporating 130 1,583,965 1,583,965 some important modifications The same reference numerals as in Figure 1 are used for similar parts in the second embodiment shown in Figure 2.

The end plates 2, 3 are spaced apart by means of a U-shaped component 170 of the first mounting means An externally screwthreaded projection 171 on each end plate is secured to a respective one arm of the component 170 by means of an associated nut 172 as shown The component 170 can be connected to an engine crankcase (not shown) by any suitable means (not shown) or could itself form part of the engine crankcase.

The partition means 5 is formed with an annular, radially inwardly directed, collar portion 173 The fluid control'means comprises a movable portion of the partition means in the form of a body 174 comprsing a radially outer portion in the form of a metal ring 175, and a radially inner portion in the form of an intermediate resilient wall 176.

The end portions of the ring 175 are bent radially outwards toform end flanges 177, 178 defining an outwardly directed, substantially, channel-shaped groove 179 around the body 174.

The collar portion 173 extends into the groove 179 and axial movement of the body 174 is limited by engagement of the flanges 177, 178 with the upper and lower portions 173 a, 173 b respectively of the collar portion 173 The wall 176, made for example from rubber, has a throttling restriction 180 of which, the upper peripheral portion adjacent to the main chamber 6 is formed with a sharp edge 181 while the lower peripheral portion adjacent to the auxiliary chamber 7 is formed with a rounded edge 182 so that the throttling restriction 180 has different flow factors in the two directions of flow The operation of this coupling is similar to the operation of the coupling shown in Figure l.

Figure 3 shows an alternative form of fluid control means which can be used in place of the fluid control means of the coupling shown in Figure 1 The fluid control means comprises a movable portion of the partition means in the form of an annular body 190 having the shape shown.

The body 190 is formed integrally with the component 73 The body 190 has a central aperture through which the bolt 150 extends to define the throttling restriction 162 The body 190 is secured to the dividing wall portion of the partition means 5 by a connecting portion in the form of a relatively thin resilient annular flange 191 -which extends radially between the body 190 and the dividing wall portion of the partition means The flange 191 offers only slight resistance to axial movements of the body 190, so that for small axial movements the movement of the body is similar to that of the body described with reference to Figure 1 For large movements the resistance of the flange 191 to deformation is -substantially increased so that the movement of the body can be considered to be restricted within predetermined allowable limits 70 Preferably, in each of the three embodiments the displacement volume of the movable portion of the partition means corresponds to a change in volume in the chambers' produced by an overall oscillatory travel of 75 the coupling of 0-2 to O 3 mm.

The invention is not limited to the particular arrangement of the end plates, chosen in the description, i e one end plate connected to the crankcase of the engine and the 80 mounting bracket connected to the engine supporting frame The arrangement can equally well be different, as desired The main and auxiliary chambers could be made as mirror images without departing from the' 85 scope of the invention.

.The coupling can also find use in couplings between rotating power sources' and powerusing machines, in that several couplings distributed around the components transmit 90 the tangential forces and hydraulically damp out the angular vibrations.

It should be noted that quite generally other frequency-dependent and amplitudedependent measures can be combined with 95 those according to the invention in order to increase the effect described above or to influence (for example to increase or decrease) the damping in a particular sense for further characteristic frequency-amplitude ranges 100

Claims (13)

WHAT WE CLAIM IS:-

1 A resilient coupling for resiliently connecting two components movable relative to each other, the coupling being in the form of a hollow body which in use of the coupling 105 contains a hydraulic damping fluid, and the interior of the body being divided by partition means of the coupling into main and auxiliary chambers between which a restricted flow of fluid can take place upon relative movement 110 between said two components, the coupling comprising first mounting means to which one of the components can be secured and which comprises two end portions of the hollow body which are spaced apart and fixed rela 115 tive to each other, second mounting means to which the other of the components can be secured and which is of an annular form, and is positioned generally between said two end portions, and resilient wall means which con 120 i nects said first and second mounting means and comprises resilient annular wall portions which connect said second mounting means with said end portions, said partition means comprising a movable portion arranged to 125 move to accommodate small variations in the volumes of the main and auxiliary chambers so that the coupling can accommodate vibrations of small amplitude without hydraulic damping 130 G 1,583,965

2 A coupling according to claim 1 in which said movable portion of the partition means is of a generally annular form providing an aperture for the passage of fluid between the, main and auxiliary chambers.

3 A coupling according to claim 2 in Which said movable portion comprises a radially outer portion, and a radially inner portion which is axially thinner than said outer portion.

4 A coupling according to claim 3 in which said inner portion is positioned axially centrally of said outer portion.

A coupling according to either one of claims 3 and 4 in which said inner portion is of resilient material.

6 A coupling according to any one of claims 2 to 5 in which said movable portion is arranged to provide different resistances to the flow of fluid through the aperture therein in opposite directions between the main and auxiliary chambers.

7 A coupling according to any one of claims 3 to 5 in which said inner portion of said movable portion is arranged to be deflected axially of said outer portion of said movable portion by a difference between the fluid pressures in the main and auxiliary chambers, said inner portion being shaped so that resistance to the flow of fluid through the aperture in said movable portion is varied by deflection of said inner portion.

8 A coupling according to claim 7 in which a radially inner peripheral surface of said inner portion, bounding said aperture in said movable portion of the partition means, is of a convex curved shape in axial crosssection.

9 A coupling according to any one of claims 1 to 5, 7 and 8 wherein said movable portion of the partition means is in the form of an annular body axially movable between two extreme positions determined by engagement of said movable portion with annular shoulders which bound an annular groove in a dividing wall portion of the partition means.

A coupling according to any one of claims 1 to 6 wherein said movable portion of the partition means is in the form of an annular body axially movable between two extreme positions determined by engagement of radially outwardly projecting end flanges of said movable portion with a dividing wall portion of the partition means.

11 A coupling according to either one of claims 9 and 10 wherein an annular gap between said movable portion and said dividing wall portion provides a passage for the flow of fluid between the chambers.

12 A coupling according to any one of claims 2 to 5 in which said movable portion is secured to a dividing wall portion of the partition means by means of a resilient annular connecting portion which extends radially between the movable portion and the dividing wall portion and permits limited axial movement of the movable portion relative to said dividing wall portion.

13 A coupling according to any one of claims 2 to 5 in which a spacing member extending between said end portions of the coupling extends through said aperture in said movable portion of the partition means to define with said movable portion an annular passage through which fluid can pass between the chambers.

BARKER, BRETTELL & DUNCAN, Chartered Patent Agents, Agents for the Applicants, 138 Hagley Road, Edgbaston, Birmingham B 16 9 PW.

Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon), Ltd -1981.

Published at The Patent Office, 25 Southampton Buildings, London, WC 2 A l AY from which copies may be obtained.