CN113646557B - Shock absorber with end-of-travel stop equipped with pressure limiting valve - Google Patents
Shock absorber with end-of-travel stop equipped with pressure limiting valve Download PDFInfo
- Publication number
- CN113646557B CN113646557B CN202080025424.7A CN202080025424A CN113646557B CN 113646557 B CN113646557 B CN 113646557B CN 202080025424 A CN202080025424 A CN 202080025424A CN 113646557 B CN113646557 B CN 113646557B
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- Prior art keywords
- stop
- piston
- chamber
- valve
- stroke
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- 239000006096 absorbing agent Substances 0.000 title description 21
- 230000035939 shock Effects 0.000 title description 21
- 239000000725 suspension Substances 0.000 claims abstract description 19
- 239000012530 fluid Substances 0.000 claims abstract description 14
- 230000006835 compression Effects 0.000 claims abstract description 11
- 238000007906 compression Methods 0.000 claims abstract description 11
- 230000000979 retarding effect Effects 0.000 description 4
- 238000013016 damping Methods 0.000 description 2
- 230000000750 progressive effect Effects 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
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
- F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
- F16F9/32—Details
- F16F9/48—Arrangements for providing different damping effects at different parts of the stroke
- F16F9/49—Stops limiting fluid passage, e.g. hydraulic stops or elastomeric elements inside the cylinder which contribute to changes in fluid damping
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Fluid-Damping Devices (AREA)
Abstract
The invention relates to a hydraulic suspension damper comprising a damper piston which slides in an inner tube (2) and which moves in an axial direction, named forward direction, during compression of the damper, which damper piston extends out of a stop piston (10) provided with a perforation (18) which enters a stop chamber (16) at the end of the stroke of the damper while fluid is pressed out of the stop chamber (16) to slow down the end of the stroke, which stop chamber (16) comprises a side perforation (44) which is arranged after a predefined stroke (C0) of the stop piston (10) in the stop chamber (16) and which side perforation is provided with a valve (34) for limiting the pressure in the stop chamber (16).
Description
Technical Field
The present invention relates to a hydraulic shock absorber arranged with an end-of-travel stop, and to a motor vehicle equipped with a shock absorber of this type.
Background
Motor vehicles typically include a suspension for each wheel that includes a suspension spring and a telescopic hydraulic shock absorber that slows the movement of the suspension. In particular, the shock absorber may include an end of hydraulic stroke stop that strongly slows down the movement before the end of stroke to avoid impact on the rigid stop.
An adjustable end-of-hydraulic-stroke stop of known type is shown in particular by document US-se:Sup>A-3207270, comprising se:Sup>A rod which receives the axial thrust of the movement to be decelerated and which causes the piston to slide in se:Sup>A cylinder having se:Sup>A series of perforations distributed over its length. A manual control system arranged outside the cylinder can adjust the closure of these perforations in order to adapt the level of deceleration of the stop.
However, the adjustment of this type of stop does not include any automatic action that can be adapted to different loads.
Another known type of stop for a vehicle suspension damper is shown in particular by document FR-A1-3050000, which comprises a lifting rod comprising a damping piston at its lower end to perform the main damping, which extends downwards out of a bushing which fits around the inner tube of the stop at the end of the compression stroke.
The bushing comprises a series of perforations distributed axially, which are closed in succession during the introduction of the tube into the bushing so as to slow down increasingly the transfer of fluid (from the outer chamber formed around the bushing) towards the chamber (inside the tube and in front of the piston). An increasingly higher deceleration of the shock absorber at the end of its compression stroke is obtained.
A thrust spring is arranged below the main piston, pressing slightly forward at the end of the stroke of said shock absorber against a nested plug (poisseau) that slides axially in a stop tube comprising additional perforations at different heights.
A regulating chamber arranged in the stop tube and below the nested stopper comprises a restricted passage for the passage of fluid outwards, so as to slow down the descending movement of the nested stopper under the action of the thrust spring and slow down the re-ascending movement of the nested stopper under the action of the return spring.
In this way, the rapid compression of the thrust spring on the nesting plug does not slow down the nesting plug (of the fluid passing through the management chamber) in a slow dynamic manner when a large run-out of the suspension is accidentally implemented for a light load vehicle. The perforations of the stop tube remain open to provide greater compliance to the end-of-travel stop, which results in greater comfort.
In the case of a loaded vehicle, the thrust spring frequently presses against the nesting plug, which frequently presses down on the nesting plug, which closes the bore of the stop tube and simultaneously hardens the end-of-travel stop more strongly. By avoiding back contact (talk) of the suspension of the load vehicle, safety is obtained. However, this type of stop comprising an adjustable nesting plug controlled by the pressure of the thrust spring can present problems, especially in the case of light-load vehicles that do not move the nesting plug, for small amplitude movements remaining at the beginning of the end-of-travel stop, there are higher speeds.
This occurs in particular when reaching the road transverse lands forming the deceleration strip. A large retarding force is thereby obtained, which degrades comfort.
Furthermore, the nested plug system with the spring is relatively complex to implement, which can cause costs.
Disclosure of Invention
The object of the present invention is, inter alia, to avoid these drawbacks of the prior art.
To this end, the invention provides a hydraulic suspension damper comprising a damper piston which slides in an inner tube and which moves in an axial direction, named forward direction, during compression of the damper, which damper piston extends out of a stop piston provided with a perforation, which stop piston enters a stop chamber at the end of the stroke of the damper, while fluid is forced out of the stop chamber to decelerate the end of the stroke, characterized in that the stop chamber comprises a side perforation which is arranged after a predefined stroke of the stop piston in the stop chamber, which side perforation is provided with a valve for limiting the pressure in the stop chamber.
The advantage of this shock absorber is that for light load vehicles, when small movements occur at higher speeds at the beginning of the end-of-travel stop, the valve opens while limiting the pressure in the stop chamber. Once the perforation is exceeded, the valve is deactivated and the end-of-travel stop operates normally.
For large movements that occur at low speeds, the pressure does not rise too much at the beginning of the end of the stroke, the valve does not open, and the stop operates normally. An automatic adaptation of the end-of-travel stop is obtained in a simple and economical manner, which ensures comfort.
The hydraulic shock absorber according to the present invention may further comprise one or more of the following features, which may be combined with each other.
Advantageously, the valve comprises a ball urged by a calibrated spring to close the lateral perforation.
In this case, the valve advantageously comprises a sleeve (douille) which carries out an external guidance of the ball and of the calibration spring.
In particular, the stop piston may be an annular piston comprising the perforations, which annular piston fits around a stop tube while closing a stop chamber arranged around the stop tube.
In this case, the valve is advantageously fixed inside the stop tube.
In particular, the sleeve of the valve may be fixed inside a tubular support fitting in the stop tube.
Advantageously, the predefined travel is between 15mm and 25 mm.
Advantageously, the shock absorber comprises a calibration spring for calibrating the valve, the calibration spring corresponding to an opening pressure for opening the valve, the opening pressure providing a retarding force between 200daN and 400daN for retarding the stop piston.
Advantageously, the shock absorber comprises a calibration spring for calibrating the valve, the calibration spring corresponding to an opening pressure for opening the valve, the opening pressure being provided by a minimum compression speed of between 1.5m/s and 2.5 m/s.
The present invention also aims to provide a motor vehicle comprising a suspension damper having any of the above-mentioned features.
Drawings
Other features and advantages of the present invention will become more apparent upon reading the following detailed description and the accompanying drawings, given by way of example, in which:
fig. 1 shows in axial section a front part of a shock absorber according to the prior art, approaching an end-of-travel stop;
fig. 2 shows the damper according to the prior art in the intermediate position of the end-of-stroke stop;
figure 3 shows the front part of the shock absorber according to the invention, approaching the end-of-travel stop; and
fig. 4 is a graph providing an example of the deceleration values of the shock absorber.
Detailed Description
Fig. 1 shows a telescopic shock absorber which performs a compression operation along a main axis towards a side generally designated front (indicated by arrow AV).
The shock absorber comprises a cylindrical inner tube 2 which houses a piston 4 (which is fixed at the end of a shock absorber rod 20) which slides sealingly and axially in the body to delimit a front chamber 6 and a rear chamber 22.
The piston 4 comprises a reduced fluid passage 8 between the front chamber 6 and the rear chamber 22, which reduces the movement of the piston according to the fluid passage direction and the fluid passage speed related to the speed of the shock absorber rod 20.
The compensation chamber forms an annular volume arranged between the inner tube 2 and an external envelope, not shown, which contains pressurized gas and receives fluid pressurized by the volume (moving during the compression operation and during the entry of the damper rod 20 into the damper).
The piston 4 extends at the front side out of a circular bush 10 which fits around the end-of-stroke stop tube 12 before the end of the stroke, while closing an annular outer stop chamber 16 formed around the tube. The stop tube 12 defines an inner chamber 26 internally and is fixed by its front end to a cap 14 closing the front end of the inner tube 2.
The bushing 10 comprises an annular outer boss 24 which ensures guiding of the bushing in the inner tube 2, and a series of radial perforations 18 which are axially aligned and have a diameter which is progressively larger.
Fig. 2 shows the advance of the bushing 10 around the stop tube 12 in the outer stop chamber 16, the fluid of which is forced from the perforations 18 with corrected cross-section towards the inner chamber 26, to carry out a gradual deceleration of the advance of the damper rod 20. The fluid then passes from the inner chamber 26 through the own reduced passage 8 to the rear volume 22 of the piston 4.
At the same time, as the rod 20 advances, the perforations 18 of the bush 10 progressively close, which increasingly reduces the overall passage section of the fluid from the stop chamber 16 to the inner chamber 26, and increases the retarding force, which becomes very large near the end of said stroke.
An increasingly greater progressive deceleration of the damper rod 20 is obtained, said progressive deceleration being determined by adapting the diameter and the position of the perforations 18 of the bush 10.
Fig. 3 shows a valve 34 fixed inside a tubular support 30 which fits in the stop tube 12 and is axially secured in position (cal) by a rear shoulder 32 which presses against the rear end of the stop tube.
The valve 34 comprises, in radial succession from the outside: a radial perforation 44 passing through both the stop tube 12 and the tubular support 30; a sphere 36; a helical calibration spring 38, which is compressed, then presses outwards on the sphere to close the radial perforation.
A sleeve 40 radially fixed in the tubular support 30, which sleeve forms a guide for the guide spring 38 and the sphere 36, comprises an internal shoulder towards the centre of the shock absorber comprising a central perforation 42 which constrains the ends of the spring so that the spring can exert pressure on the sphere.
Before the predefined stroke C0, the movement of the bushing 10 around the stop tube 12 opens the radial perforation 44, and the valve 34 can operate in the unloading mode when the pressure in the stop chamber 16 exceeds a threshold value (enabling the ball 36 to retract while enabling the calibration spring 38 to compress).
After a predefined stroke C0, the bushing 10 exceeds the radial perforation 44 while closing it, the operation of the end-of-stroke stop no longer being dependent on the valve 34.
Fig. 4 shows the deceleration force F (on the vertical axis in daN) for decelerating the attack stop as a function of the stroke C (in mm) from the start of said end-of-stroke stop for different movement speeds (in m/s) of the piston 4. The predefined travel C0 is 20mm.
In particular, for small speeds of 0.1m/s, the force F is very weak up to a stop stroke of about 35mm, which then rises to about 200daN. Conversely, for a greater speed of 5m/s, the force F rises rapidly to reach 500daN at 20mm, which eventually ends at about 700 daN. For speed values between 1.5m/s and 2.5m/s, the force F exceeds 300daN at a stroke of 20mm, which is uncomfortable. This condition is obtained, for example, when reaching a deceleration strip on the road forming a boss, which provides a greater compression speed of the shock absorber with a smaller movement.
In this case, above a minimum force F0 of 300daN, the pressure in the stop chamber 16 is sufficiently large to open the valve 34 while compressing the spring 38. A correction 50 to the curve is obtained which limits the force F to 300daN up to the predefined stroke C0. After this predefined stroke C0, the liner 10 closes the perforations 44 of the valve 34, said curve returning to its normal form.
In a variant, the pressure limiting valve 34 may be arranged on other types of end-of-travel stops, for example comprising a stop piston equipped with perforations, which enters into a stop tube to carry out a deceleration of the end-of-travel of the stop piston.
By means of the simple valve 34 comprising very few constituent elements, an uncomfortable operating region 52, which is limited by a maximum value of the predefined stroke C0 and a minimum value of the force F0 (in particular between 200daN and 400 daN), is avoided simply, effectively and economically.
Claims (7)
1. A hydraulic suspension damper comprising a damper piston (4) sliding in an inner tube (2) and moving in an axial direction, named forward direction (AV), during compression of the hydraulic suspension damper, the damper piston (4) extending out of a stop piston (10) equipped with a perforation (18) which enters into a stop chamber (16) at the end of the stroke of the hydraulic suspension damper while forcing fluid out of the stop chamber (16) to slow down the end of the stroke, the stop chamber (16) comprising a side perforation (44) arranged after a predefined stroke (C0) in the stop chamber (16) of the stop piston (10) which is equipped with a valve (34) for limiting the pressure in the stop chamber (16), characterized in that the stop piston (10) is a ring piston comprising the perforation (18) which is adapted around a stop tube (12) while forcing fluid out of the stop chamber (16) to slow down the end of the stroke, the stop chamber (16) comprising a side perforation (44) which is arranged after a predefined stroke (C0) in the stop chamber (16), the side perforation being equipped with a valve (34) for limiting the pressure in the stop chamber (16), the ring piston (10) being adapted to a ring piston (12) which is fitted around the perforation spring (18) while the pre-defined between the stop chamber (16) and the calibration spring (25 mm, the calibration spring (38) is used for calibrating the opening of the damper spring (25 mm, the opening pressure provides a deceleration force between 200daN and 400daN for decelerating the stopper piston (10).
2. The hydraulic suspension damper according to claim 1, wherein the valve (34) comprises a ball (36) urged by a calibrated spring (38) to close the side aperture (44).
3. The hydraulic suspension damper according to claim 2, characterized in that the valve (34) comprises a sleeve (40) implementing external guidance for the ball (36) and the calibration spring (38).
4. A hydraulic suspension damper according to any one of claims 1 to 3, characterized in that the valve (34) is fixed inside the stop tube (12).
5. A hydraulic suspension damper according to claim 3, characterized in that the sleeve (40) of the valve (34) is fixed inside a tubular support (30) fitted in the stop tube (12).
6. A hydraulic suspension damper according to any one of claims 1 to 3 and 5, wherein the opening pressure is provided by a minimum compression speed of between 1.5m/s and 2.5 m/s.
7. A motor vehicle comprising a suspension damper, characterized in that the motor vehicle comprises a hydraulic suspension damper according to any one of claims 1 to 6.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR1903228A FR3094434B1 (en) | 2019-03-28 | 2019-03-28 | SHOCK ABSORBER WITH LIMIT STOPS EQUIPPED WITH A PRESSURE LIMITATION VALVE |
| FR1903228 | 2019-03-28 | ||
| PCT/FR2020/050224 WO2020193883A1 (en) | 2019-03-28 | 2020-02-10 | Damper with travel limit stop provided with a pressure limit valve |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113646557A CN113646557A (en) | 2021-11-12 |
| CN113646557B true CN113646557B (en) | 2023-12-01 |
Family
ID=67262687
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202080025424.7A Active CN113646557B (en) | 2019-03-28 | 2020-02-10 | Shock absorber with end-of-travel stop equipped with pressure limiting valve |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP3948012A1 (en) |
| CN (1) | CN113646557B (en) |
| FR (1) | FR3094434B1 (en) |
| WO (1) | WO2020193883A1 (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3207270A (en) * | 1964-08-31 | 1965-09-21 | Ellis Fluid Dynamics Corp | Shock absorber including adjustable metering orifices |
| US4026533A (en) * | 1975-08-29 | 1977-05-31 | Hennells Ransom J | Shock absorber with conical control elements |
| DE102010023870A1 (en) * | 2010-06-15 | 2011-02-10 | Daimler Ag | Pneumatic spring damping device, particularly two-tube pneumatic spring damping device for motor vehicle, has compensation chamber with throttle device |
| CN107013623A (en) * | 2016-05-13 | 2017-08-04 | 北京京西重工有限公司 | The hydraulic damper of stopping element is compressed with hydraulic machinery |
| FR3050496A1 (en) * | 2016-04-25 | 2017-10-27 | Peugeot Citroen Automobiles Sa | HYDRAULIC SUSPENSION SYSTEM OF A VEHICLE |
| CN108884895A (en) * | 2016-04-08 | 2018-11-23 | 标致雪铁龙汽车股份有限公司 | It is equipped with the hydraulic buffer of the attack stop part with adjustable braking rule |
| CN108930754A (en) * | 2017-05-24 | 2018-12-04 | 标致雪铁龙汽车股份有限公司 | End of travel for oscillating movement can adjust automatically hydraulic pressure block |
-
2019
- 2019-03-28 FR FR1903228A patent/FR3094434B1/en active Active
-
2020
- 2020-02-10 WO PCT/FR2020/050224 patent/WO2020193883A1/en unknown
- 2020-02-10 CN CN202080025424.7A patent/CN113646557B/en active Active
- 2020-02-10 EP EP20707731.4A patent/EP3948012A1/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3207270A (en) * | 1964-08-31 | 1965-09-21 | Ellis Fluid Dynamics Corp | Shock absorber including adjustable metering orifices |
| US4026533A (en) * | 1975-08-29 | 1977-05-31 | Hennells Ransom J | Shock absorber with conical control elements |
| DE102010023870A1 (en) * | 2010-06-15 | 2011-02-10 | Daimler Ag | Pneumatic spring damping device, particularly two-tube pneumatic spring damping device for motor vehicle, has compensation chamber with throttle device |
| CN108884895A (en) * | 2016-04-08 | 2018-11-23 | 标致雪铁龙汽车股份有限公司 | It is equipped with the hydraulic buffer of the attack stop part with adjustable braking rule |
| FR3050496A1 (en) * | 2016-04-25 | 2017-10-27 | Peugeot Citroen Automobiles Sa | HYDRAULIC SUSPENSION SYSTEM OF A VEHICLE |
| CN107013623A (en) * | 2016-05-13 | 2017-08-04 | 北京京西重工有限公司 | The hydraulic damper of stopping element is compressed with hydraulic machinery |
| CN108930754A (en) * | 2017-05-24 | 2018-12-04 | 标致雪铁龙汽车股份有限公司 | End of travel for oscillating movement can adjust automatically hydraulic pressure block |
Also Published As
| Publication number | Publication date |
|---|---|
| FR3094434B1 (en) | 2021-11-19 |
| EP3948012A1 (en) | 2022-02-09 |
| CN113646557A (en) | 2021-11-12 |
| WO2020193883A1 (en) | 2020-10-01 |
| FR3094434A1 (en) | 2020-10-02 |
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