GB2298020A - Elastomeric vibration-damping bushing with hydraulic damping - Google Patents
Elastomeric vibration-damping bushing with hydraulic damping Download PDFInfo
- Publication number
- GB2298020A GB2298020A GB9503245A GB9503245A GB2298020A GB 2298020 A GB2298020 A GB 2298020A GB 9503245 A GB9503245 A GB 9503245A GB 9503245 A GB9503245 A GB 9503245A GB 2298020 A GB2298020 A GB 2298020A
- Authority
- GB
- United Kingdom
- Prior art keywords
- bushing
- channel
- inner sleeve
- walls
- working chamber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F13/00—Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs
- F16F13/04—Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs comprising both a plastics spring and a damper, e.g. a friction damper
- F16F13/06—Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs comprising both a plastics spring and a damper, e.g. a friction damper the damper being a fluid damper, e.g. the plastics spring not forming a part of the wall of the fluid chamber of the damper
- F16F13/08—Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs comprising both a plastics spring and a damper, e.g. a friction damper the damper being a fluid damper, e.g. the plastics spring not forming a part of the wall of the fluid chamber of the damper the plastics spring forming at least a part of the wall of the fluid chamber of the damper
- F16F13/14—Units of the bushing type, i.e. loaded predominantly radially
- F16F13/1481—Units of the bushing type, i.e. loaded predominantly radially characterised by features of plastic springs, e.g. presence of cavities or stiffeners; characterised by features of flexible walls of equilibration chambers, i.e. membranes
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Combined Devices Of Dampers And Springs (AREA)
Abstract
The bushing (10) comprises an inner sleeve (12); an outer sleeve substantially coaxial with the inner sleeve; a block (16) of resilient material retained between the inner sleeve and the outer sleeve, and shaped to define two working chambers (18,20) that are filled with hydraulic fluid. Each working chamber is defined in part by a pair of walls (19,21) of predetermined thickness (T 1 ,T 2 ) which extend between the inner sleeve and the outer sleeve and which curve outwardly from the inner sleeve to the outer sleeve. A channel (22) interconnects the two chambers for fluid flow therebetween. The thickness of the walls of one working chamber is different from the thickness of the walls of the other working chamber in order to improve the control of compliance characteristics for the bushing.
Description
A BUSHING
The present invention relates to a bushing for use on a motor vehicle to suppress vibrations.
Vibration damping bushings are used on motor vehicles in association with suspension systems, steering systems, and engine and transmission mounting systems. A basic design of bushing comprises inner and outer coaxial metallic sleeves with a moulded elastomeric block therebetween. A development of this arrangement provided the formation of two working chambers in the elastomeric block with a channel interconnecting the chambers. Hydraulic fluid substantially fills the chambers. During vibration damping action of the bushing, fluid is pumped between the two chambers by way of the channel. An example of this prior art can be found in US Patent No. 5178375.
An example of a similar arrangement for engine mounts is disclosed in US Patent No. 4720086. These known arrangements have limited opportunity for optimal tuning of the bushing.
It is an object of the present invention to overcome the above mentioned disadvantage.
To this end, a bushing in accordance with the present invention comprises an inner sleeve; an outer sleeve substantially coaxial with the inner sleeve; a block of resilient material retained between the inner sleeve and the outer sleeve, and being shaped to define two working chambers that are substantially filled with hydraulic fluid, each working chamber being defined in part by a pair of walls of predetermined thickness which extend between the inner sleeve and the outer sleeve and which curve outwardly from the inner sleeve to the outer sleeve; and a channel interconnecting the two chambers for fluid flow therebetween; wherein the thickness of the walls of one working chamber is different from the thickness of the walls of the other working chamber.
By having walls of different thicknesses, the compliance of a bushing in accordance with the present invention is better set and controlled, thereby allowing optimum tuning of the damping characteristics of the bushing for a particular application.
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a cross-section view on the line
I-I of Figure 2 of a bushing in accordance with the present invention;
Figure 2 is a cross-sectional view on the line II-II of Figure 1;
Figure 3 is a perspective view of the inner sleeve and elastomeric block of the bushing of Figure 1;
Figure 4 is a schematic presentation of the channel and the fluid restriction passage of the bushing of Figure 1;
Figures 5 and 6 are graphs of damping energy and dynamic stiffness respectively against frequency for the bushing shown in Figures 1 to 3;
Figures 7 and 8 are graphs of damping energy and dynamic stiffness respectively against frequency for another embodiment of bushing in accordance with the present invention; and
Figures 9 and 10 are graphs of damping energy and dynamic stiffness respectively against frequency for a prior art bushing.
Referring to Figures 1 to 3, a bushing 10 in accordance with the present invention comprises an inner sleeve 12, an outer sleeve 14, and a block 16 of resilient material therebetween. The inner and outer sleeves 12 and 14 are substantially cylindrical and coaxial, and formed from any suitable metallic material. Although shown as circular in crosssection, the inner sleeve may have another other suitable cross-section. The block 16 is moulded from elastomeric material onto the inner sleeve 12, with the outer sleeve 14 being attached thereafter. Formed within the block 16 are two working chambers, a pumping chamber 18 and a release chamber 20. The pumping chamber 18 has a smaller volume than the release chamber 20. The longitudinally extending walls 19,21 of each chamber 18,20 respectively curve outwardly from the inner sleeve 12 to the outer sleeve 14.The walls 19 of the pumping chamber 18 have a substantially constant predetermined thickness T1.
The walls 21 of the pumping chamber 20 have a substantially constant predetermined thickness T2.
Both chambers 18,20 are substantially filled with hydraulic fluid. The shape of the walls 19,21 substantially prevents loss of fluid pressure in the chambers 18,20 when the inner sleeve 12 moves relatively towards the outer sleeve 14. A channel 22 is formed in the outer surface 23 of the block 16, extends circumferentially, and is connected at either end by openings 24,26 with the pumping chamber 18 and the release chamber 20 respectively. During damping operation of the bushing 10, the inner and outer sleeves 12,14 move relative to one another to cause hydraulic fluid to be pumped from one chamber 18,20 to the other chamber by way of the channel 22. As so far described, the bushing 10 is known to those skilled in the art.
In accordance with the present invention, T1 has a different value to T2. In a preferred arrangement T1 is greater than T2 although in certain cases T2 may be greater than T1. The preferred range for the ratio T1:T2 is between 1 and 20.
A flow restriction passage 28 is preferably positioned within the channel 22. The passage 28 is preferably moulded integrally with the block 16.
Alternatively, an additional metal sleeve (not shown) may be positioned between the outer sleeve 14 and the block 16 to provide a metallic lining for the channel and to define the flow restriction passage. The presence of the passage 28 in the channel 22 provides better damping at low frequency vibrations for the bushing 10.
The channel 22 is preferably formed with a predetermined length L and a predetermined maximum diameter or width D (see Figure 4) either side of the flow restriction passage 28. In a preferred arrangement, the ratio of L/D lies in the range of 1 to 18. Further, the passage 28 is preferably formed with a predetermined length 1 and a predetermined maximum diameter or width d (see Figure 4). In a preferred arrangement, the ratio of l/d also lies in the range of 1 to 18, and is preferably the same as the ratio of L/D. The values for L, D, 1 and d are predetermined to provide the required compliance verses vibration frequency characteristics and the required dynamic stiffness verses vibration frequency characteristics for the bushing 10. The passage 28 is preferably situated at the mid-point of the channel 22.It is possible that the maximum diameter or width of the channel 22 may be different on either side of the passage 28. However, it is preferable that the maximum diameter or width of the channel 22 remains substantially constant along the length of the channel. The cross-sectional shape of the channel 22 is preferably substantially V-shape as shown, or semicircular.
The graphs of Figures 5 and 6 indicate plots of dynamic stiffness K* and damping energy or compliance C, respectively, against frequency f for the bushing 10 of Figures 1 to 4, the case where T1 is greater than T2. The graphs of Figures 7 and 8 indicate plots of dynamic stiffness K* and damping energy or compliance C, respectively, against frequency f for the bushing 10 of Figures 1 to 4, the case where T2 is greater than T1. By comparison, the graphs of Figures 9 and 10 indicate plots of dynamic stiffness K* and damping energy or compliance C, respectively, against frequency f for a bushing where
T1 is equal to T2. It will be appreciated that providing a bushing 10 with different wall thicknesses for the pumping and release chambers 18,20 changes the compliance and dynamic stiffness characteristics of the bushing 10, and that the compliance characteristics can be easily controlled by such different wall thicknesses. Consequently, the bushing 10 can be tuned to meet any predetermined requirements for damping.
As an alternative to the above described arrangement, the block may be formed from any suitable plastics material.
Attention is drawn to our patent application nos. (Ref. No. MJD/H-182114) and
(Ref. No. MJD/H-187271), filed the same day as the present application, the disclosures in which are incorporated herein by reference.
Claims (8)
1. A bushing comprising an inner sleeve; an outer sleeve substantially coaxial with the inner sleeve; a block of resilient material retained between the inner sleeve and the outer sleeve, and being shaped to define two working chambers that are substantially filled with hydraulic fluid, each working chamber being defined in part by a pair of walls of predetermined thickness which extend between the inner sleeve and the outer sleeve and which curve outwardly from the inner sleeve to the outer sleeve; and a channel interconnecting the two chambers for fluid flow therebetween; wherein the thickness of the walls of one working chamber is different from the thickness of the walls of the other working chamber.
2. A bushing as claimed in Claim 1, wherein one of the working chambers has a smaller volume than the other working chamber.
3. A bushing as claimed in Claim 2, wherein the thickness of the pair of walls of said one working chamber is greater than the thickness of the pair of walls of the said other working chamber.
4. A bushing as claimed in any one of
Claims 1 to 3, wherein a flow restriction passage is positioned in the channel to restrict the flow of fluid through the channel between the two chambers.
5. A bushing as claimed in any one of
Claims 1 to 4, wherein the channel extends circumferentially around the outer surface of the block.
6. A bushing as claimed in any one of
Claims 1 to 5, wherein the block is moulded from elastomeric material and wherein the block and the channel are moulded as an integral formation.
7. A bushing as claimed in any one of
Claims 1 to 5, wherein the channel is defined by a metallic insert positioned between the block and the outer sleeve.
8. A bushing substantially as herein described with reference to, and as shown in, Figures 1 to 8 of the accompanying drawings.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9503245A GB2298020B (en) | 1995-02-18 | 1995-02-18 | A bushing |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9503245A GB2298020B (en) | 1995-02-18 | 1995-02-18 | A bushing |
Publications (3)
Publication Number | Publication Date |
---|---|
GB9503245D0 GB9503245D0 (en) | 1995-04-12 |
GB2298020A true GB2298020A (en) | 1996-08-21 |
GB2298020B GB2298020B (en) | 1997-05-07 |
Family
ID=10769865
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9503245A Expired - Fee Related GB2298020B (en) | 1995-02-18 | 1995-02-18 | A bushing |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2298020B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2672137A1 (en) * | 2012-06-06 | 2013-12-11 | Firma Carl Freudenberg | Hydraulic support |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102020134593A1 (en) * | 2020-12-22 | 2022-06-23 | Vibracoustic Se | Hydraulic bush with support points and method for manufacturing such a bush |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4861004A (en) * | 1987-10-27 | 1989-08-29 | Marugo Rubber Industries, Ltd. | Fluid damped elastomeric bushing |
EP0503687A2 (en) * | 1987-07-23 | 1992-09-16 | Firma Carl Freudenberg | Bushing-type rubber spring |
US5178376A (en) * | 1989-10-05 | 1993-01-12 | Firma Carl Freudenberg | Hydraulically damped rubber cartridge spring |
US5199691A (en) * | 1990-11-13 | 1993-04-06 | Hutchinson | Hydraulic anti-vibration sleeves |
-
1995
- 1995-02-18 GB GB9503245A patent/GB2298020B/en not_active Expired - Fee Related
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0503687A2 (en) * | 1987-07-23 | 1992-09-16 | Firma Carl Freudenberg | Bushing-type rubber spring |
US4861004A (en) * | 1987-10-27 | 1989-08-29 | Marugo Rubber Industries, Ltd. | Fluid damped elastomeric bushing |
US5178376A (en) * | 1989-10-05 | 1993-01-12 | Firma Carl Freudenberg | Hydraulically damped rubber cartridge spring |
US5199691A (en) * | 1990-11-13 | 1993-04-06 | Hutchinson | Hydraulic anti-vibration sleeves |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2672137A1 (en) * | 2012-06-06 | 2013-12-11 | Firma Carl Freudenberg | Hydraulic support |
Also Published As
Publication number | Publication date |
---|---|
GB9503245D0 (en) | 1995-04-12 |
GB2298020B (en) | 1997-05-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4693456A (en) | Fluid-filled resilient bushing with circumferential orifice | |
EP0386735B1 (en) | Upper support for shock absorber in a suspension system | |
US4749173A (en) | Fluid-filled resilient bushing having damping means within fluid chambers | |
US4921229A (en) | Fluid-filled elastic center bearing mount | |
EP1870613B1 (en) | Vibration isolator | |
EP0723091B1 (en) | Fluid-filled elastic bushing having displacement restrictor with elastic buffer and stiff abutting part | |
EP0566178A1 (en) | Hydraulic torque strut with decoupling and related mounting system | |
CN110770465B (en) | Damper with reduced volume insert | |
JP2598969B2 (en) | Fluid-filled cylindrical mounting device | |
US5299788A (en) | Fluid-filled cylindrical elastic mount having orifice passages and voids formed in elastic body | |
GB2289110A (en) | Fluid-filled elastomeric suspension bushing assembly | |
JPS62224746A (en) | Fluid seal type vibrationproof supporting body | |
GB2298019A (en) | Elastomeric vibration-damping bushing with hydraulic damping | |
US5060918A (en) | Fluid-filled cylindrical elastic connector having two orifice passages with different cross sectional areas | |
US4971300A (en) | Motor mount having improved hydraulic damping | |
US6749186B2 (en) | Hydraulic bushing with springs in parallel | |
GB2298018A (en) | Elastomeric vibration-damping bushing with hydraulic damping | |
US4854561A (en) | Elastic bushing filled with viscous fluid | |
GB2298020A (en) | Elastomeric vibration-damping bushing with hydraulic damping | |
EP1118794B1 (en) | Fluid filled cylindrical elastic mount having intermediate sleeve exhibiting improved deformation resistance and method of producing the same | |
US4941649A (en) | Fluid-filled cylindrical elastic mount having means for improved durability of elastic body | |
US5088701A (en) | Fluid-filled cylindrical elastic mount having grooved movable block(s) in fluid chamber(s) | |
EP0410455A1 (en) | Fluid-filled cylindrical elastic mount having annular fluid chamber with constant cross sectional area over the entire circumference | |
EP3478987B1 (en) | A damping bushing | |
KR100661526B1 (en) | Hydro Bush for front lower arm of automobile |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20100218 |