DE102015225170A1 - Single-pipe vibration damper with an end cushioning, strut with a one-pipe vibration damper with an end cushioning and vehicle with a one-pipe vibration damper with a cushioning - Google Patents

Abstract

The invention relates to a single-pipe vibration damper with a cushioning for a vehicle, a strut and a vehicle with such a vibration damper, wherein the vibration damper has a first working space and a second working space and a working piston device and a separating piston device, wherein the first working space with a Hydraulic medium can be filled, wherein the second working space, based on a functional installation state in a vehicle, below the first working space, wherein the separating piston means comprises a displaceable within the second working space along a longitudinal damper damper piston, the second working space in a fillable with a hydraulic medium Hydraulic volume and a gas pressure accumulator volume divides, wherein the gas pressure accumulator volume is filled with a gaseous medium and can be acted upon by a defined pressure, wherein the first working space and d he second working space are separated by a fixed intermediate floor and in the intermediate floor, a valve device is arranged, with which a fluid flow of a hydraulic medium between the first working space and the hydraulic volume of the second working space is variable.

Description

The invention relates to a single-pipe vibration damper with a cushioning for a vehicle, in particular for a two-lane motor vehicle, wherein the vibration damper has a damper housing with a first working space and a second working space and a working piston device and a separating piston device. The first working space is at least partially filled with a hydraulic medium, wherein the second working space, based on a functional installation state in a vehicle, is located below the first working space. The working piston device is movable within the first working space along a damper longitudinal axis relative to the damper housing between an upper end position and a lower end position and has a piston rod with a lower end and an upper end and, based on a functional installation state of the vibration damper in a vehicle, in the region of the lower end attached to the piston rod working piston. The upper end of the piston rod is led out of the damper housing, wherein the separating piston device has a separating piston displaceable within the second working chamber along the damper longitudinal axis, which divides the second working chamber into a hydraulic volume which can be filled with a hydraulic medium and a gas pressure storage volume. The gas pressure storage volume can be filled with a gaseous medium and acted upon by a defined pressure and, based on a functional installation state of the vibration damper, is located below the hydraulic volume.

Furthermore, the invention relates to a strut with a single-tube vibration damper with a cushioning for a vehicle and a vehicle, in particular a two-lane motor vehicle, with a single-tube vibration damper with a cushioning, especially with a strut with a single-tube vibration damper with a cushioning.

Single-tube vibration damper with end position damping, in particular with a so-called stroke-dependent damping, d. H. an attenuation which varies over the stroke of the working piston, for example, such that the damping is reduced by the central position and increases progressively in an end-position range, in particular to prevent strike-through, are basically known from the prior art.

For example, is from the DE 102 57 008 A1 a designed as an air damper vibration damper known in which the Dämpferverhärtung in the end position range can be progressively progressively increased by means of a pressure increase in the vibration damper.

In addition, one-pipe vibration dampers are known, which, based on a functional installation state in a vehicle below the working piston device have a second piston device with a second working piston, which is also attached to the piston rod of the working piston device, wherein the second working piston in a lower end position range, that is shortly before reaching the lower end position or a bottom dead center, immersed in a tapered damper tube. Due to the tapered geometry of the damper tube, the damper force increases progressively, so that a progressive cushioning can be achieved.

Some one-pipe vibration dampers with a previously described, second piston device additionally have a gas pressure storage volume arranged in the region of a damper bottom as compensation volume for a displaced volume of the hydraulic medium during compression of the working piston device, whereby the gas pressure storage volume is separated from the overlying working space by means of a so-called separating piston device.

Due to the required for end cushioning, second working piston device have above-described single-tube vibration dampers in relation to single-tube vibration dampers without cushioning on the one hand more components or components, on the other they usually build longer, that is, they have a larger Installation length and thus require more space.

Based on this prior art, it is an object of the present invention to provide a single-pipe vibration damper with cushioning, with a particularly simple way, a cushioning can be realized, in particular a cushioning with progressive characteristic, wherein the single-tube Vibration damper in particular has the shortest possible length. It is another object of the invention to provide a corresponding strut with a single-tube vibration damper with end position damping for a vehicle and a vehicle with such a one-pipe vibration damper with cushioning.

This object is achieved by a vibration damper with the features of claim 1 and by a strut with the features of claim 21 and a vehicle having the features of claim 22. Advantageous and preferred embodiments of the invention are the subject of the other claims and are in Explained in more detail below. The wording of the claims is incorporated herein by express reference. Some of the following, mentioned features are to avoid repetition, sometimes only described once, that is only in connection with the vibration damper itself, the strut or the vehicle, but apply independently for both the vibration damper, as well as for the strut and the vehicle.

A single-tube vibration damper according to the invention is characterized in that the first working space and the second working space are separated by a fixed intermediate bottom and a valve device is arranged in the intermediate bottom, with which a fluid flow of a hydraulic medium between the first working space and the hydraulic volume of the second working space can be changed.

In other words, in the case of a single-tube vibration damper according to the invention, between the first working space, in which the working piston attached to the piston rod is movable along the damper longitudinal axis, and the second working space, in which the separating piston device is arranged with the separating piston can also be moved along the damper longitudinal axis, a fixed intermediate bottom is provided with a valve device. According to the invention, with the valve device in the intermediate bottom, the fluid flow of a hydraulic medium, with which a one-tube vibration damper according to the invention is preferably filled in a functional use state, can be changed between the first working space and the hydraulic volume of the second working space and thus the damper force.

In a functional condition of use, that is, in a ready for use state, a single-tube vibration damper according to the invention, the first working space is preferably at least partially filled with a hydraulic medium, in particular with a correspondingly suitable hydraulic oil, as is the case of conventional one-tube vibration absorbers known in the art.

Furthermore, in a functional use state, the gas pressure storage volume of the second working space of a single-tube vibration damper according to the invention is preferably filled with nitrogen gas and pressurized, in particular at a pressure of about 20 to 30 bar. In some applications, it may be advantageous if the gas pressure accumulator volume is subjected to a pressure of about 50 bar or higher, wherein the pressure which is applied to the gas pressure accumulator volume is preferably selected so large that the pressure in the gas accumulator volume is greater than a maximum expected hydraulic working pressure in the hydraulic volume of the second working space to avoid a spring effect of the gas pressure storage volume.

The gas pressure accumulator volume is used in a single-tube vibration damper according to the invention also, as in known from the prior art single-tube vibration dampers with a gas pressure accumulator volume, as a compensation chamber or compensating volume to a volume compensation for the displaced by the piston rod during compression volume of the To enable hydraulic medium.

The damper housing of a single-tube vibration damper according to the invention is preferably at least partially cylindrical, in particular the first and the second working space are preferably at least partially cylindrical, wherein particularly preferably the first working dream and / or the second working space is cylindrical in each case over its entire length , In some cases, it may be advantageous if the second working space has a smaller cross section than the first working space. However, this is not mandatory.

An inventive single-tube vibration damper is preferably designed as a passive vibration damper or semi-active vibration damper, wherein in a semi-active vibration damper damper force usually by changing a fluid flow between an upper working volume above the working piston and a lower working volume below the working piston by means of or a damper force resulting for a set fluid flow in a semi-active vibration damper usually depends on the damper speed, so how fast the damper is "compressed" or "pulled apart". In order to change the fluid flow, a semi-active vibration damper usually has one or more damper valves, preferably each arranged in the working piston, with a controllable actuating element which, in a functional installation state of the vibration damper in a vehicle, in particular in dependence on a driving state of the vehicle, electronic, hydraulic, mechanically, mechatronically or in a similar way can be controlled.

In an advantageous embodiment of a single-tube vibration damper according to the invention, the valve device is designed such that the Fluid flow of the hydraulic medium between the first working space and the hydraulic volume of the second working space can be varied stroke dependent, preferably in a lower end position range of the working piston, that is in a range before a bottom dead center of the working piston, in particular such that in the lower end position range with increasing stroke of the working piston when damper the damping force increases, particularly preferably progressive, that is disproportionately. As a result, a puncture of the vibration damper can be avoided. In particular, block formation of the working piston with the intermediate bottom can be prevented in this manner during compression.

For the purposes of this application, the lower end position range is understood to mean an area in front of a bottom dead center of the working piston, wherein the bottom dead center defines a lower end position of the working piston.

In a further advantageous embodiment of a single-tube vibration damper according to the invention, the valve device arranged in the intermediate bottom is a mechanical valve device. As a result, a particularly cost-effective end position damping can be realized in a single-tube vibration damper, since no electronic control or regulation is required. Furthermore, mechanical valve devices are usually more robust than electronic ones.

In a further advantageous embodiment of a single-tube vibration damper according to the invention, the valve device has a stroke-dependent valve and / or a throttle valve and / or a check valve.

The stroke-dependent valve is preferably designed, depending on a current stroke of the working piston, that is, depending on a current position of the working piston in damper longitudinal direction, a fluid flow of the hydraulic medium during compression and / or rebound of the vibration from the first working space in the second working space, in particular to adjust or change from a lower working volume of the first working space in the hydraulic volume of the second working space.

The throttle valve is preferably designed for throttling the fluid flow from the first working space into the second working space, in particular for throttling the fluid flow from the lower working volume in the first working space into the hydraulic volume of the second working space, whereby with an appropriate configuration of the throttle valve, an increased increase in the damping force can be achieved.

The check valve allows the rebound preferably a back flow of the hydraulic medium from the hydraulic volume in the lower working volume of the first working space. That is, preferably, the check valve opens when the working piston along the damper longitudinal axis is moved upward again upwards, so that the hydraulic medium can flow according to the stroke of the working piston.

In a further advantageous embodiment of a vibration damper according to the invention, the valve device is designed such that at a compression, starting from an upper end position of the working piston, the stroke-dependent valve is open until the working piston reaches a first stroke position, so that in a functional use state with hydraulic medium in the first Working space the hydraulic medium, in particular during compression until reaching the first stroke position, can flow through the open, stroke-dependent valve in the intermediate bottom of the first working space in the hydraulic volume.

With increasing pressure in the hydraulic volume, the separating piston in the second working space moves downwards, whereby the pressure in the gas pressure accumulator volume increases. As a result, the damping force increases, especially in the end position range.

Preferably, the stroke-dependent valve is thereby, in particular until it reaches the first stroke position, preferably opened unchanged, d. H. with a constant opening cross section.

Particularly preferably, until the first stroke position is reached by the working piston, the throttle valve and the check valve are closed.

In a further advantageous embodiment of a vibration damper according to the invention, the valve device is designed such that after reaching the first stroke position in a further compression, preferably until the working piston reaches a second stroke position, the stroke-dependent valve increasingly closes, especially steadily, preferably the stroke-dependent valve upon reaching of the second operating point is completely closed.

Preferably, the stroke-dependent valve is designed such that it closes steadily due to the rising in the first working space hydraulic working pressure, in particular due to rising in a lower part of the first working space hydraulic working pressure.

In a further advantageous embodiment of a vibration damper according to the invention the valve device formed in the intermediate floor such that upon further compression after reaching the second stroke position and / or when exceeding a minimum hydraulic working pressure in the lower working volume of the first working space, the throttle valve opens and the hydraulic fluid through the throttle valve from the first working space in the hydraulic volume of the second Working space flows, wherein the stroke-dependent valve preferably closes and / or remains closed.

This means that in an advantageous embodiment of a vibration damper according to the invention, the valve device is designed such that the stroke-dependent valve is open until reaching the first stroke position by the working piston, with further compression in a range between the first stroke position and the second position, the stroke-dependent valve increasingly closes, especially steadily and after opening the second stroke position with further compression, the throttle valve opens or is open, wherein preferably the stroke-dependent valve is closed or remains closed. Particularly preferably, the valve device is designed such that the stroke-dependent valve closes upon reaching the second stroke position and remains closed upon further compression.

In a further advantageous embodiment of a vibration damper according to the invention, the valve device is designed such that in a rebound, starting from a stroke position below the second stroke position, the check valve opens or is open, wherein preferably the throttle valve closes or is closed. In other words, in an advantageous embodiment of a vibration damper according to the invention, the valve device is designed such that during rebound the hydraulic medium in the hydraulic volume of the second working chamber flows through the check valve back into the lower working volume of the first working chamber and preferably not through the throttle valve therethrough.

In a further advantageous embodiment, the stroke-dependent valve and the check valve are formed by a common valve. That is, the valve device preferably has a valve which has a stroke-dependent valve function and a check valve function.

In a further advantageous embodiment, the stroke-dependent valve is adapted to adjust the fluid flow by changing an opening cross-section of a flow opening or to change, in particular to set defined.

In a further advantageous embodiment of a vibration damper according to the invention, the stroke-dependent valve is mechanically coupled to the separating piston arranged in the second working space such that an axial displacement of the separating piston in the damper longitudinal direction downwardly causes an opening of the stroke-dependent valve due to an increasing hydraulic pressure in the hydraulic volume of the second working space, preferably a steadily increasing closure, wherein the closure of the stroke-dependent valve is effected in particular by a continuous reduction of an opening cross section of a flow opening in the stroke-dependent valve in the intermediate floor. This can be achieved in particular that the damper force increases progressively only in the lower end position range.

In a further advantageous embodiment of a vibration damper according to the invention, the separating piston is mechanically coupled to the stroke-dependent valve in such a way that the separating piston continues to be displaceable downwards in the damper longitudinal direction even after the stroke-dependent valve has been closed, for which purpose preferably the separating piston via a spring with a correspondingly selected spring rate is coupled with the stroke-dependent valve. As a result, the pressure in the hydraulic volume of the second working chamber may continue to increase even after closing the stroke-dependent valve and the separating piston continue to move in damper longitudinal direction down, the pressure in the hydraulic volume as a result of the throttle valve from the lower working volume of the first working space in the hydraulic volume of the second Working space flowing hydraulic medium continues to increase.

In a further advantageous embodiment of a vibration damper according to the invention, the stroke-dependent valve on a senkkopfförmige flow opening, which is preferably closed by means of a conical valve plug with a countersunk head. As a result, a continuous closure of the stroke-dependent valve can be achieved in a particularly simple manner, wherein the conical valve plug can be displaced downwards preferably in the damper longitudinal direction by the increasing hydraulic working pressure in the lower working volume of the first working space, so that the stroke-dependent valve with increasing hydraulic working pressure in the lower working volume of the first working space closes. The increase of the hydraulic working pressure in the lower working volume of the first working space is effected by the displacement of the piston device in damper longitudinal direction down, that is by the compression, and is thus dependent on the stroke, wherein the increase of the hydraulic working pressure in particular on the displacement of Piston rod and as a result displaced by the piston rod volume of the hydraulic medium in the first working space is due. The case covered by the valve plug is, in particular until the closing of the stroke-dependent valve, preferably proportional to the stroke during compression or to the compression travel of the piston rod.

Particularly preferably, the displacement of the separating piston is proportional to the displacement of the piston rod, preferably over the entire stroke or the entire compression travel, in particular over the entire stroke when rebounding or the entire Ausfederweg.

In a further advantageous embodiment of a vibration damper according to the invention, a valve rod is arranged or fixed below the conical valve plug of the stroke-dependent valve, wherein in particular at the lower end of the valve rod, a valve plate is attached.

In a further advantageous embodiment of a vibration damper according to the invention, the separating piston on its upper, the hydraulic volume of the second working chamber facing piston surface fixed to the separating piston connected to a cylindrical pot with a pot bottom and an opening in the middle of the pot bottom, the pot with its bottom of the pot Intermediate bottom is attached to the separating piston.

In a further advantageous embodiment of a vibration damper according to the invention, the valve rod is guided through the opening in the bottom of the pot, so that the valve disk is within the pot, wherein the opening in the bottom of the pot preferably has a smaller diameter than the valve plate, so that the pot bottom during rebound a Stop for the valve plate forms upwards.

In a further advantageous embodiment of a vibration damper according to the invention, the valve disk is supported by a spring on the pot bottom, in particular via a cylindrical coil spring. As a result, it can be achieved that the stroke-dependent valve automatically opens during rebound, whereby a valve can be realized in a simple manner with a stroke-dependent valve function and a non-return valve function.

In a further advantageous embodiment of a vibration damper according to the invention, the throttle valve is designed and tuned to the stroke-dependent valve that it opens during compression only when the stroke-dependent valve is closed and / or when a minimum hydraulic working pressure in the first working space is exceeded, in particular a minimum hydraulic working pressure in the lower working volume of the first working space. In other words, that is, the throttle valve preferably opens only when a defined minimum compression travel or a defined minimum stroke has been covered by the working piston, in particular only when the working piston has reached the first stroke position.

In a further advantageous embodiment of a vibration damper according to the invention, the throttle valve is formed by a spring disk valve, in particular by a arranged in the intermediate bottom flow opening, which can be closed by means attached to the underside of the false floor spring washer, wherein the spring washer is preferably bolted to the underside of the false floor. About the spring stiffness of the spring washer can be adjusted when the throttle valve opens, especially at which hydraulic working pressure in the lower working volume of the first working space.

In an advantageous embodiment of a vibration damper according to the invention, the individual components of the vibration damper are designed and matched to one another so that the working piston does not block with the intermediate piston and the separating piston does not block with a bottom of the gas pressure storage volume and / or the intermediate bottom. That is, preferably, the components of the stroke-dependent valve, such as the valve rod attached to the separating piston cylindrical pot, the valve plug and the spring, via which the valve plate is supported on the pot bottom, geometrically matched to each other, especially with respect to their lengths in damper longitudinal direction. For only if the individual components are designed such that a block formation of the working piston and a block formation of the separating piston is avoided, a puncture of the vibration damper can be effectively avoided.

An inventive strut is characterized in that it comprises a single-tube vibration damper according to the invention.

An inventive vehicle is characterized in that it comprises a single-tube vibration damper according to the invention, in particular a strut according to the invention with a vibration damper according to the invention.

These and other features are apparent from the claims and from the description also from the drawings, wherein the individual features in each case alone or more in the form of sub-combinations in a Embodiment of the invention be realized and can represent advantageous and inherently protectable versions for which protection is claimed here.

In the following the invention with reference to two preferred embodiments will be further explained, the invention being schematically illustrated in the accompanying drawings. 1 shows a known from the prior art single-tube vibration damper with end position damping in a schematic representation, wherein the vibration damper has a gas pressure storage volume in the region of the damper bottom. 2 shows a first embodiment of a single-tube vibration damper according to the invention, also in schematic representation, 3a A second embodiment of a single-tube vibration damper according to the invention in longitudinal section, 3b a lower portion of the single-tube vibration damper according to the invention 3a in an enlarged view, 4a a lower portion of the vibration damper according to the invention from the 3a and 3b with the working piston in a position before reaching a first stroke position, 4b the vibration damper according to the invention from the 3a . 3b and 4a with a position of the working piston after reaching the first stroke position, 4c the vibration damper from the 3a . 3b . 4a and 4b with the working piston in a second stroke position and 4d the vibration damper according to the invention from the 3a . 3b . 4a to 4c in a position of the working piston after reaching the second stroke position. 5 shows the vibration damper according to the invention from the 3a to 4d during a rebound movement with the working piston in a position between a lower end position and the second stroke position. Essential to the invention may be all features described in more detail.

The in 1 shown, known from the prior art single-tube vibration damper 1 has a piston device 4 with a piston rod 4A , a first working piston 4B and one at the bottom of the piston rod 4A attached second power piston 6 on, wherein the piston means along a not shown here damper longitudinal axis in a damper housing 2 is axially displaceable. The first working piston 4B shares a first working space 5 of the vibration damper 1 in an upper working volume 5A as well as a lower work volume 5B , wherein in the first working piston 4B a damper throttle valve 3A and a damper check valve 3B are arranged, by means of which a hydraulic medium, also not shown here, with which the first working space 5 can at least partially be filled, from the upper working volume 5A in the lower working volume 5B can flow.

Furthermore, the above-described vibration damper 1 a second workspace 7 at least partially below the first working space 6 located, based on a functional installation state of the vibration damper 1 in a vehicle. The workroom 7 has a smaller cross section than the working space 6 , where the cross section of the working space 7 in addition, in the upper section of the second working space 7 tapered from top to bottom.

The second workroom 7 is through a separating piston 8th also divided into two working volumes, in particular in an upper, designed as a hydraulic volume working volume 7A and a lower working volume configured as a gas pressure storage volume 7B , The gas storage volume 7B is filled with nitrogen gas and subjected to a pressure of about 30 bar and by means of a separating piston 8th , which is mounted axially displaceable in damper longitudinal direction, relative to the hydraulic volume 7A sealed.

The two working pistons 4B and 6 are each fixed to the piston rod 4A connected, so that during a compression movement, that is, during a downward movement of the piston rod 4A , both the first working piston 4B , as well as the second working piston 6 Move down towards the damper bottom and upwards when rebounding.

By means of the damper valves 3A and 3B can, in this embodiment, preferably in response to a damper speed or in dependence on the speed at which the piston rod 4A moved in damper longitudinal direction, a fluid flow of the hydraulic medium, not shown here, with which the vibration damper 1 is filled in a functional use state, between the upper working volume 5A and the lower working volume 5B be set. In this case, the damper throttle valve is preferred for adjusting the fluid flow during compression 3A provided and for adjusting the fluid flow during rebound the damper check valve 3B , wherein in each case by means of a change of the fluid flow, a damper force can be changed.

The self-adjusting damping force is greater, the lower the resulting fluid flow.

With increasing stroke of the piston rod 4A or of the first working piston 4B , that is, with increasing compression travel, is also the second working piston 6 increasingly moving downhill. Due to the smaller cross section of the second working space 7 , especially in the area of the upper working volume 7A or the hydraulic volume 7A rises as soon as the second working piston 6 in the second workspace 7 dips in, the damper force. Due to the tapering cross section of the second working space 7 especially progressive.

In other words, that in the known from the prior art single-tube vibration damper 1 a progressive end position damping by means of an additional, at least partially below the first working space 5 arranged second working space 7 is effected, wherein a progressive end position damping means of a tapered cross section of the second working space 6 and a second working piston 6 is reached.

The gas storage volume 7B serves, as usual in generic single-tube vibration dampers with gas pressure storage volume, as a compensating volume for that in a compression movement from the first working space 5 through the piston rod 4A displaced volume of the hydraulic medium, wherein for compensating the volume of gas absorbed in the gas pressure accumulator is compressed accordingly, since the volume of the gas pressure accumulator decreases with increasing pressure.

2 shows a first embodiment of a single-tube vibration damper according to the invention 11 wherein a single-tube vibration damper according to the invention also comprises a piston device 14 with a piston rod 14A and a first working piston 14B has and a first work space 15 with an upper working volume 15A and a lower workload 15B which are inside a cylindrical damper housing 12 are arranged.

The single-tube vibration damper according to the invention 11 also has two damper valves 13A and 13B on, in particular also a damper throttle valve 13A and a damper check valve 13B in which, depending on a damper speed, in particular as a function of an input or rebound speed of the piston device 14 or of the working piston 14B , A damper force can be adjusted, to which also the fluid flow of a hydraulic medium through the working piston 14B can be changed.

As in the previously described one-tube vibration damper known from the prior art 1 has the single-tube vibration damper according to the invention 11 also a second workspace 17 on. However, this is completely below the first working space 15 , in particular below the lower working volume 15B ,

And in contrast to the known from the prior art single-tube vibration damper 1 is in this embodiment of a single-tube vibration damper according to the invention 11 the first workroom 15 by means of a fixed intermediate floor 19 that is, a non-displaceable in the axial direction or not displaceable intermediate floor 19 from the second workroom 17 separated.

In the second workroom 17 is also a separating piston 18 arranged, which the second working space 17 also in an upper, designed as a hydraulic volume working volume 17A and a lower one, as a gas pressure storage volume 17B trained volume divides. The gas storage volume 17B is filled with nitrogen gas and subjected to a pressure of about 30 bar. In some cases it may also be necessary to pressurize the gas accumulator volume with a pressure of up to 50 bar, depending on which hydraulic working pressure in the lower working volume 15B maximum occurs, because the pressure in the gas pressure storage volume 17B should always be greater than the maximum occurring hydraulic working pressure in the lower working volume 15B ,

In the fixed intermediate floor 19 which is the first workroom 15 , in particular the lower working volume 15B , from the second workroom 17 , in particular the hydraulic volume 17A separates, is a valve device 20 arranged, which is a stroke-dependent valve 20A , a throttle valve 20B and a check valve 20C having.

The only sketchy illustrated, stroke-dependent valve 20A In this embodiment, there is an unspecified flow-through opening as well as a likewise not designated valve stopper and one below the valve 20A , Also in this illustration unspecified, associated with the valve plug on the valve rod, via which the valve plug with the separating piston 18 is coupled. Above the valve plug a coil spring is arranged, which is also not specified.

The stroke-dependent valve 20A is designed such that during compression, starting from an upper end position, that is, a top dead center of the first working piston 14B , until reaching a first stroke position, the stroke-dependent valve 20A is open, wherein in this stroke range, that is in the range from the upper end position of the working piston to the first stroke position, an opening cross-section of the flow opening of the stroke-dependent valve remains almost constant.

With increasing stroke of the working piston 14B is increasingly hydraulic medium from the lower working volume 15B in the hydraulic volume 17A promoted by the flow opening of the stroke-dependent valve. This increases the pressure in the hydraulic volume 17A increasingly on until the separating piston 18 begins to move in damper longitudinal direction towards damper floor. Because of the separating piston 18 via the valve stem with the valve plug of the stroke-dependent valve 20A is connected, the valve plug is increasingly lowered towards the damper floor until the stroke-dependent valve upon reaching a second stroke position, which with a corresponding pressure in the hydraulic volume 17A correlates, closes.

With further increasing stroke of the working piston or a further compression movement and as a result increasing hydraulic working pressure in the lower working volume 15B opens, in particular only when a minimum working pressure in the lower working volume is exceeded 15B , but the throttle valve 20B the valve device 20 in the intermediate floor 19 , so that continues hydraulic medium from the first working space 15 or the lower working volume 15B in the hydraulic volume 17A of the second working space 17 flows. As a result, the pressure in the hydraulic volume decreases 17A even further, causing the separating piston 18 is further shifted towards damper bottom until the lower end position is reached. Due to the special design of the stroke-dependent valve 20A with the unspecified, arranged between the valve plug and the valve disc coil spring can also after closing the stroke-dependent valve 20A the separating piston 18 be moved further towards damper floor. This block formation is prevented and the breakdown of the damper can be avoided.

When rebounding, starting from the lower end position first closes the throttle valve 20B in the intermediate floor 19 , wherein the stroke-dependent valve 20A remains closed as long as the first working piston 14B located below the second stroke position. However, it opens the check valve 20C , so that's in the hydraulic volume 17A accumulated hydraulic fluid through the check valve 20C back to the first workroom 15 , especially in the lower working volume 15B , can flow. As a result, the separating piston moves 18 back up, wherein upon reaching the second stroke position, the stroke-dependent valve 20A slowly starts to open again until reaching the first stroke position, when it has reached its full open position.

3a shows a second embodiment of a single-tube vibration damper according to the invention 111 , this vibration damper 111 also a damper housing 112 and a displaceable in damper longitudinal direction L piston device 114 with a piston rod 114A and a first piston attached to the lower end of the piston rod 114B having a first working space 115 in an upper working volume 115A and a lower working volume 115B Splits.

This vibration damper according to the invention 111 also has a second, but completely below the first working space 115 arranged second working space 117 on, which also by means of a separating piston 118 , which is also axially displaceable in damper longitudinal direction L, in a hydraulic volume 117A and a gas storage volume 117B is divided in the damper bottom. The gas storage volume 117B is also filled with nitrogen gas and also subjected to a pressure of about 30 bar and by means of the separating piston 118 opposite the hydraulic volume 117A sealed.

In the working piston 114B are also a damper throttle valve 113A and a damper check valve 113B intended. In this embodiment, however, the valve device 120 , which are in the area of the false floor 119 is shown in more detail.

In contrast to that on the basis of 2 described embodiment of a single-tube vibration damper according to the invention 11 are in this invention one-tube vibration damper 111 the stroke-dependent valve 120A and the check valve 120C formed by a common valve. That is, in this single-tube vibration damper according to the invention 111 is a stroke-dependent valve function and a check valve function by a single valve 120 provided.

As with the basis of 2 described single-tube vibration damper according to the invention has the stroke-dependent valve 120A also a valve plug 121 on and a flow opening 126 , which in particular by means of 3b , which the lower portion of the vibration damper according to the invention 111 out 3a shows in an enlarged view, is easily recognizable. The valve plug 121 In this case has a countersunk head with a conical shaft arranged below, wherein the geometry of the valve plug 121 to the geometry of the flow opening 126 is adapted or vice versa, in particular such that the flow-through 126 by means of the valve plug 121 can be completely and tightly closed.

Below the conical valve stem of the valve plug 121 there is a valve stem 122 at the lower end of the cone-shaped Shank with the valve plug 121 firmly connected and at its lower end a valve plate 125 having. About one on the separating piston 118 , in particular on its upper side, attached cylindrical pot 123 having an opening in the bottom of the pot, through which the valve stem 122 is performed, wherein the diameter of the opening in the bottom of the pot is smaller than the diameter of the valve disk 125 , and one between the valve plate 125 and the bottom of the pot 123 clamped cylindrical coil spring 124 is the valve rod 122 with the separating piston 118 coupled.

The valve rod 122 the stroke-dependent valve 120A is doing so with the separating piston 118 coupled, that a downward movement of the separating piston 118A due to an increasing hydraulic pressure in the hydraulic volume 117A an increasing closure of the stroke-dependent valve 120A causes. This is the closure of the stroke-dependent valve 120A achieved in that during a downward movement of the separating piston 118 that is to say with a displacement of the separating piston 118 towards the damper bottom, which is fixed to the separating piston 118 connected cylindrical pot 123 also moved down.

About the coil spring 124 , which on the valve plate 125 is supported, the downward movement is on the valve stem 122 transferred, which firmly with the valve plug 121 connected so that the valve plug 121 is also displaced towards damper bottom. By the senkkopfförmige or conical geometry of the valve plug 121 and the corresponding configuration of the flow-through 126 causes a downward movement of the valve plug 121 in the direction damper floor to an increasing closure of the flow opening 126 and thus to a reduction of the fluid flow from the first working space 115 or from the lower working volume 115B in the second workspace 117 or in the hydraulic volume 117A , As a result, the damper force increases. The vibration damper according to the invention 111 is designed such that the damper force during compression depending on the distance traveled stroke of the working piston 114B increases.

In the illustration in 3b is right next to the stroke-dependent valve 120A , which at the same time as a check valve 120C is used and is designed such that during rebound by a pressure difference between the hydraulic volume 117A and the lower working volume 115B the valve plug 121 is again moved upwards, a throttle valve 120B recognizable, which in this case by a flow-through 127 and a spring washer 128 which is formed from a bottom at the intermediate floor 119 screwed on, so that at a hydraulic working pressure in the lower working volume 115B that exceeds a required minimum working pressure, the spring washer 128 from the intermediate bottom can be pushed down and the throttle valve 120B opens.

4a shows the embodiment of the vibration damper according to the invention from the 3a and 3b with the working piston 114B in a position before reaching the first stroke position H1, in which the stroke-dependent valve 120A begins to close increasingly. In this case, it is easy to see how the stroke-dependent valve 120A is open and the throttle valve 120B closed is.

With increasing stroke of the working piston 114B , Especially after reaching the first stroke position H1, with further increasing compression travel is increasingly hydraulic medium from the lower working volume 115B in the hydraulic volume 117A promoted, causing the separating piston 118 in the direction of damper bottom, see 4b , As a result, as indicated by 3a and 3b already explained, the valve plug 121 also in the direction of the intermediate floor 119 moved down so that the flow-through 126 the stroke-dependent valve 120A is increasingly closed until it is completely closed when reaching the second stroke position H2. The throttle valve remains 120B initially closed.

Reached the power piston 114B now the second stroke position H2, see 4c , is the stroke-dependent valve 120A completely closed and the throttle valve 120B is still completely closed.

Upon further compression and as a result further increasing displacement of the hydraulic medium in the first working space 115 through the piston rod 114A the pressure increases in the lower working volume 115B continues, with the result that when reaching or exceeding a minimum working pressure in the lower working volume 115B the spring washer 128 of the throttle valve 120B due to the hydraulic pressure acting on it from the underside of the false floor 119 takes off, see 4d , This allows hydraulic fluid through the flow opening 127 through the intermediate floor 119 from the lower working volume 115B in the hydraulic volume 117A stream. This has the consequence that the separating piston 118 is further shifted towards damper floor.

Because the valve plug 121 can no longer follow this movement, the separating piston 118 However, it must continue to be moved towards the damper bottom to a corresponding compensation volume for the from the lower working volume 115B displaced, in the hydraulic volume 117A To provide flowing hydraulic medium, in this embodiment, the valve rod 122 or the valve spring plate 125 not firmly with the separating piston 118 connected but via the coil spring 124 and the cylindrical pot 123 with the separating piston 118 coupled, so that by the spring travel of the coil spring 124 an additional stroke of the separating piston 118 is available. This is indicated by the stroke marked S1 in FIG 4d symbolizes.

5 shows the vibration damper according to the invention from the 3a to 4d during rebound, starting from the lower end position with the working piston 114B in a position below the second stroke position H2, in which state the throttle valve 120B is completely closed.

The check valve 120C or the stroke-dependent valve 120A are open to a backflow of the hydraulic medium from the hydraulic volume 117A in the lower working volume 115B of the first workroom 115 to enable. Opening the check valve 120C is in this case by in consequence of the upward movement of the piston device 114 resulting pressure difference between the hydraulic volume 117A and the lower working volume 115B triggered, which causes the valve plug 121 is moved upward. Over the valve stem 122 This will be the upward movement of the valve plug 121 on the valve plate 125 Transfer, first, the coil spring 124 is compressed. This is in 5 symbolically through the stroke S2 of the valve disk 125 shown, wherein the stroke S2 is greater than the stroke of S1 4d ,

Is sufficient hydraulic fluid from the hydraulic volume 117A in the first workroom 115 Backflowed, the gas pressure storage volume 117B expand again and the separating piston 118 As a result, it moves upward, which in turn causes the valve plug 121 continues to move up and the check valve 120C continue to open until it is fully open.

The individual components of a single-tube vibration damper according to the invention, in particular the individual components of the valve device 120 in the area of the false floor 119 are in order to avoid penetration of the vibration damper, preferably designed such that a block formation is avoided. Particularly preferred are the length of the cylindrical pot 123 and the spring rate of the coil spring 124 and a block height of the coil spring 124 so designed and in particular matched to each other that the spring 124 does not go to block, preferably in no operating condition.

Of course, a variety of modifications, in particular of structural modifications, to the illustrated embodiments possible without departing from the content of the claims.

LIST OF REFERENCE NUMBERS

1

One-pipe vibration damper of the prior art

2

damper housing

3A

Damper throttle valve in the working piston

3B

Damper check valve in the working piston piston device

4A

piston rod

4B

working piston

5

first working space

5A

upper working volume

5B

lower working volume

6

second working piston

7

second workspace

7A

hydraulic volume

7B

Gas storage volume

8th

separating piston

11, 111

Inventive single-tube vibration damper

12, 112

damper housing

13A, 113A

Damper throttle valve in the working piston

13B, 113B

Damper check valve in the working piston

14, 114

piston device

14A, 114A

piston rod

14B, 114B

working piston

15, 115

first working space

15A, 115A

upper working volume

15B, 115B

lower working volume

17, 117

second workspace

17A, 117A

hydraulic volume

17B, 117B

Gas storage volume

18, 118

separating piston

19, 119

fixed intermediate floor

20, 120

Valve device in the intermediate floor

20A, 120A

stroke-dependent valve

20B, 120B

throttle valve

20C, 120C

check valve

121

valve plug

122

valve rod

123

cylindrical pot

124

coil spring

125

valve disc

126

Flow opening of the stroke-dependent valve in the intermediate floor

127

Flow opening of the throttle valve in the intermediate bottom

128

spring washer

L

Damper longitudinal direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10257008 A1 [0004]

Claims (22)

Single-tube vibration damper ( 11 . 111 ) with a cushioning for a vehicle, in particular for a two-lane motor vehicle, wherein the vibration damper ( 11 . 111 ) a damper housing ( 12 . 112 ) with a first work space ( 15 . 115 ) and a second workspace ( 17 . 117 ) and a working piston device ( 14 . 114 ) and a separating piston device, wherein the first working space ( 15 . 115 ) is at least partially filled with a hydraulic medium, wherein the second working space ( 17 . 117 ), based on a functional installation state in a vehicle, below the first working space ( 15 . 115 ), wherein the working piston device ( 14 . 114 ) within the first working space ( 15 . 115 ) along a damper longitudinal axis (L) relative to the damper housing ( 12 . 112 ) is movable between an upper end position and a lower end position and a piston rod ( 14A . 114A ) having a lower end and an upper end and a, based on a functional installation state of the vibration damper ( 11 . 111 ) in a vehicle, in the region of the lower end on the piston rod ( 14A . 114A ) attached working piston ( 14B . 114B ), wherein the upper end of the piston rod ( 14A . 114A ) from the damper housing ( 12 . 112 ) is led out, wherein the separating piston means a within the second working space ( 17 . 117 ) along the damper longitudinal axis (L) displaceable separating piston ( 18 . 118 ), the second working space ( 17 . 117 ) into a hydraulic volume which can be filled with a hydraulic medium ( 17A . 117A ) and a gas pressure storage volume ( 17B . 117B ), whereby the gas pressure storage volume ( 17B . 117B ) is filled with a gaseous medium and can be acted upon with a defined pressure and, based on a functional installation state of the vibration damper ( 11 . 111 ) below the hydraulic volume ( 17A . 117A ), characterized in that the first working space ( 15 . 115 ) and the second workspace ( 17 . 117 ) by a fixed intermediate floor ( 19 . 119 ) are separated from each other and in the intermediate floor ( 19 . 119 ) a valve device ( 20 . 120 ) is arranged, with a fluid flow of a hydraulic medium between the first working space ( 15 . 115 ) and the hydraulic volume ( 17A . 117A ) of the second working space ( 17 . 117 ) is changeable. Vibration damper ( 11 . 111 ) according to claim 1, characterized in that the valve device ( 20 . 120 ) is designed such that the fluid flow of the hydraulic medium between the first working space ( 15 . 115 ) and the hydraulic volume ( 17A . 117A ) of the second working space ( 17 . 117 ) is dependent on the stroke variable, preferably at least in a lower end position range of the working piston ( 14B . 114B ), in particular such that in the lower end position range with increasing stroke of the working piston ( 14B . 114B ) increases the damping force during compression, preferably progressive. Vibration damper ( 11 . 111 ) according to claim 1 or 2, characterized in that the valve device ( 20 . 120 ) is a mechanical valve device. Vibration damper ( 11 . 111 ) according to at least one of the preceding claims, characterized in that the valve device ( 20 . 120 ) a stroke-dependent valve ( 20A . 120A ) and / or a throttle valve ( 20B . 120B ) and / or a check valve ( 20C . 120C ) having. Vibration damper ( 11 . 111 ) according to at least one of the preceding claims, in particular according to claim 4, characterized in that the valve device ( 20 . 120 ) is formed such that during a compression, starting from an upper end position of the working piston ( 14B . 114B ), the stroke-dependent valve ( 20A . 120A ) is open until the working piston ( 14B . 114B ) reaches a first stroke position, wherein in a functional use state with hydraulic medium in the first working space ( 15 . 115 ) the hydraulic medium through the open, stroke-dependent valve ( 20A . 120A ) in the intermediate floor ( 19 . 119 ) from the first workspace ( 15 . 115 ) can flow into the hydraulic volume. Vibration damper ( 11 . 111 ) according to at least one of the preceding claims, in particular according to claim 4 or 5, characterized in that the valve device ( 20 . 120 ) is designed such that after reaching the first stroke position (H1) in a further compression, until the working piston ( 14A . 114B ) reaches a second stroke position (H2), the stroke-dependent valve ( 20A . 120A ) increasingly closes, in particular continuously, wherein preferably the stroke-dependent valve ( 20A . 120A ) is completely closed when reaching the second stroke position (H2). Vibration damper ( 11 . 111 ) according to at least one of the preceding claims, in particular according to at least one of claims 4 to 6, characterized in that the valve device ( 20 . 120 ) is designed such that upon further compression after reaching the second stroke position (H2) and / or when exceeding a minimum hydraulic working pressure in the lower working volume ( 15B . 115B ) of the first working space ( 15 . 115 ) the throttle valve ( 20B . 120B ) opens and the hydraulic medium through the throttle valve ( 20B . 120B ) from the first workspace ( 15 . 115 ) in the hydraulic volume ( 17A . 117A ) of the second working space ( 17 . 117 ), wherein the stroke-dependent valve ( 20A . 120A ) preferably closes and / or remains closed. Vibration damper ( 11 . 111 ) according to at least one of the preceding claims, in particular according to at least one of claims 4 to 7, characterized in that the valve device ( 20 . 120 ) is designed such that, in a rebound, starting from a stroke position below the second stroke position (H2), the check valve ( 20C . 120C ) is opened or opened, wherein preferably the throttle valve ( 20B . 120B ) closes or is closed. Vibration damper ( 111 ) according to at least one of the preceding claims, in particular at least according to claim 4, characterized in that the stroke-dependent valve ( 120A ) and the check valve ( 120C ) by a common valve ( 120A . 120C ) are formed. Vibration damper ( 11 . 111 ) according to at least one of the preceding claims, in particular at least according to claim 4, characterized in that the stroke-dependent valve ( 20A . 120A ) is adapted to the fluid flow by changing an opening cross-section of a flow opening ( 126 ), in particular to set defined. Vibration damper ( 11 . 111 ) according to at least one of the preceding claims, in particular at least according to claim 4, characterized in that the stroke-dependent valve ( 20A . 120A ) in such a way with the in the second work space ( 17 . 117 ) arranged separating piston ( 18 . 118 ) is mechanically coupled, that an axial displacement of the separating piston ( 18 . 118 ) in damper longitudinal direction (L) downwards due to an increasing hydraulic pressure in the hydraulic volume ( 17A . 117A ) of the second working space ( 17 . 117 ) a closure of the stroke-dependent valve ( 20A . 120A ), preferably a steadily increasing closure, wherein the closure in particular by a continuous reduction of an opening cross-section of a flow-through ( 126 ) in the stroke-dependent valve ( 20A . 120A ) in the intermediate floor ( 19 . 119 ) is effected. Vibration damper ( 11 . 111 ) according to at least one of the preceding claims, in particular at least according to claim 4, characterized in that the separating piston ( 18 . 118 ) in such a way with the stroke-dependent valve ( 20A . 120A ) is mechanically coupled, that the separating piston ( 18 . 118 ) even after closing the stroke-dependent valve ( 20A . 120A ) is further in the damper longitudinal direction (L) downwardly displaceable, to which preferably the separating piston ( 18 . 118 ) via a spring ( 124 ) with appropriately selected spring rate with the stroke-dependent valve ( 20A . 120A ) is coupled. Vibration damper ( 111 ) according to at least one of the preceding claims, in particular at least according to claim 4, characterized in that the stroke-dependent valve ( 120A ) a senkkopfförmige flow opening ( 126 ), which by means of a conical valve plug ( 121 ) is closable with a countersunk head. Vibration damper ( 111 ) according to claim 13, characterized in that below the conical valve plug ( 121 ) a valve rod ( 122 ) is arranged, in particular at the lower end of the valve rod ( 122 ) a valve plate ( 125 ) is attached. Vibration damper ( 111 ) according to at least one of the preceding claims, characterized in that the separating piston ( 118 ) on its upper, the hydraulic volume ( 117A ) of the second workspace ( 117 ) facing piston surface one fixed to the separating piston ( 118 ), cylindrical pot ( 123 ) having a pot bottom and an opening in the center of the bottom of the pot, wherein the pot ( 123 ) with its bottom of the pot to the intermediate bottom ( 119 ) on the separating piston ( 118 ) is attached. Vibration damper ( 111 ) according to at least one of the preceding claims, in particular at least according to claims 14 and 15, characterized in that the valve rod ( 122 ) is guided through the opening in the bottom of the pot, so that the valve disc ( 125 ) within the pot ( 123 ), wherein the opening in the bottom of the pot has a smaller diameter than the valve plate ( 125 ). Vibration damper ( 111 ) according to at least one of the preceding claims, in particular according to claim 16, characterized in that the valve disc ( 125 ) via a spring ( 124 ) is supported on the bottom of the pot, in particular via a cylindrical coil spring ( 124 ). Vibration damper ( 11 . 111 ) according to at least one of the preceding claims, in particular at least according to claim 4, characterized in that the throttle valve ( 20B . 120B ) is designed in such a way and on the stroke-dependent valve ( 20A . 120A ) is adjusted so that it only opens during compression when the stroke-dependent valve ( 20A . 120A ) is closed and / or if a minimum hydraulic working pressure in the first working space ( 15 . 115 ), in particular a minimum hydraulic working pressure in the lower working volume ( 15B . 115B ) of the first working space ( 15 . 115 ). Vibration damper ( 11 . 111 ) according to at least one of the preceding claims, in particular at least according to claim 4, characterized in that the throttle valve ( 120B ) through a Spring disk valve is formed, in particular by a in the intermediate floor ( 119 ) arranged flow opening ( 127 ), which by means of a at the bottom of the false floor ( 119 ) fixed spring washer ( 128 ) is lockable, wherein the spring washer ( 128 ) preferably at the bottom of the intermediate floor ( 119 ) is screwed. Vibration damper ( 11 . 111 ) according to at least one of the preceding claims, characterized in that the individual components of the vibration damper ( 11 . 111 ) are designed and matched to one another such that the working piston ( 14B . 114B ) not on block with the intermediate floor ( 19 . 119 ) and the separating piston ( 18 . 118 ) not with a bottom of the gas storage volume ( 17B . 117B ) and / or the intermediate floor ( 19 . 119 ) goes to block. Suspension strut with a one-pipe vibration damper ( 11 . 111 ) with a cushioning for a vehicle, characterized in that the vibration damper ( 11 . 111 ) is designed according to one of claims 1 to 20. Vehicle, in particular two-lane motor vehicle, with a one-pipe vibration damper ( 11 . 111 ) with a cushioning, in particular with a strut with a single-tube vibration damper ( 11 . 111 ), characterized in that the vibration damper ( 11 . 111 ) is designed according to one of claims 1 to 20.

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