Vibration damper for motor vehicle

Abstract

The invention relates to a shock absorber (10) for a motor vehicle, comprising a shock absorber tube (12) and a working piston (18), which is arranged axially displaceably in the shock absorber tube (12) and divides the interior of the shock absorber tube (12) into a working space on the piston rod side (22) and a working space remote from the piston rod (24), wherein the working piston (18) comprises a main piston (14), a first additional piston (26) and a second additional piston (28), and wherein the additional pistons (26, 28) each comprise an additional valve device (46, 48) and the additional pistons (26, 28) are fluidically connected to one another via a flow channel (50).

Description

[0001] The invention relates to a motor vehicle shock absorber having a frequency-sensitive damping system.

[0002] A known vibration absorber with a frequency-sensitive damping system is described, for example, in DE 10 2016 208 845 A1. Typically, known vibration absorbers with a frequency-sensitive damping system are only provided on one side, i.e. for the rebound phase or the compression phase. It would be desirable to be able to design the structure of the compression and rebound phases independently for different frequency ranges of vibration absorber excitation. Furthermore, known vibration absorbers with a frequency-sensitive damping system have a slow adjustment of the damping force in low speeds or low damping force ranges.

[0003] Based on this, the object of the present invention is to provide a shock absorber with a frequency-sensitive damping system, which can work independently in the rebound and / or compression phases and can achieve frequency-sensitive damping force adjustment even in a low speed or low damping force range.

[0004] According to the invention, this object is achieved by a device having the features stated in independent claim 1. Additional preferred embodiments are described in the dependent claims.

[0005] According to a first aspect, a motor vehicle shock absorber comprises: a shock absorber cylinder and a working piston axially movable in the shock absorber cylinder, the piston dividing the inner chamber of the shock absorber cylinder into a working chamber close to the piston rod and a working chamber remote from the piston rod, wherein the working piston comprises a main piston and at least or exactly two additional pistons. Each additional piston comprises an additional valve device, the additional pistons being fluidically connected to each other via a flow channel so that hydraulic fluid can flow from one additional piston to another additional piston via the flow channel.

[0006] Preferably, the working piston comprises a first additional piston arranged in a working chamber close to the piston rod and a second additional piston arranged in a working chamber remote from the piston rod. The additional valve device of the first additional piston is preferably connected to the second additional piston via a flow channel, and the additional valve device of the second additional piston is preferably connected to the first additional piston via a flow channel. Thus, the working chamber of the shock absorber is fluidically connected to one another via the flow channel and the two additional pistons. The hydraulic fluid can flow through the flow channel, in particular in the rebound and compression phases of the shock absorber.

[0007] The working piston with the main piston and two additional pistons arranged in different working chambers achieves additional damping of the hydraulic fluid in the rebound and compression phases via additional valve arrangements for the additional pistons. In addition, the separate arrangement of the two additional pistons enables independently adjustable damping in the rebound and compression phases.

[0008] The shock absorber can be a single-tube shock absorber or a multi-tube shock absorber. For example, a multi-tube shock absorber for a vehicle comprises an outer tube and an inner tube arranged coaxially therewith, a balance chamber for accommodating a hydraulic fluid is formed between the outer tube and the inner tube, and a working piston connected to a piston rod is provided, the working piston is arranged in the inner tube so as to be able to reciprocate in the inner tube, and the inner chamber of the inner tube is divided into a first working chamber close to the piston rod and a second working chamber away from the piston rod by the working piston. The balance chamber is preferably at least partially filled with gas, preferably at its upper end. The outer tube preferably at least partially forms the housing of the shock absorber. The inner surface of the inner tube preferably serves as a guide for the working piston. The working piston preferably comprises a valve device, by which the first working chamber and the second working chamber are connected to each other. In the case of a single-tube shock absorber, the outer tube is preferably not provided. The inner tube is called a damping cylinder and, as described above in relation to the inner tube, accommodates the piston rod and the working piston.

[0009] In the case of a multi-tube or single-tube shock absorber, the shock absorber in particular comprises a sealing assembly which is arranged and disposed on the piston rod side to fluidically seal the inner cavity of the outer tube. The end of the inner tube on the piston rod side is preferably fixed to the sealing assembly. On the opposite side of the sealing assembly, i.e. the end remote from the piston rod, the balancing chamber and the second working chamber are preferably fluidically connected to each other via a bottom valve. The balancing chamber is preferably fluidically connected to the first or second working chamber via an opening in the inner tube. For example, the balancing chamber is connected to the inner tube via a bottom valve.

[0010] In the case of a monotube shock absorber, the shock absorber comprises in particular a sealing assembly which is designed and arranged on the piston rod side to fluidically seal the inner chamber of the shock absorber cartridge. The end of the shock absorber cartridge on the piston rod side is preferably fixed to the sealing assembly. On the opposite side of the sealing assembly, i.e. the end remote from the piston rod, the inner chamber of the shock absorber cartridge is preferably fluidically sealed by an axially movable sealing element. The sealing element preferably separates the gas space adjacent thereto from the working chamber filled with hydraulic fluid in the axial direction.

[0011] In the following description, the term "shock absorber" refers to both multi-tube shock absorbers and mono-tube shock absorbers, wherein the "shock absorber tube" is the inner tube of the multi-tube shock absorber.

[0012] For example, a flow channel is provided in the piston rod, which fluid channel connects the additional valve devices of the additional pistons to each other in fluid. The working chamber remote from the piston rod and the working chamber on the piston rod side are preferably connected to each other in fluid via the flow channel and the additional valve device. The flow channel is especially configured as a substantially annular space and axially passes through the piston rod. The flow channel preferably comprises a plurality of flow paths for guiding the hydraulic fluid to the respective additional pistons, in particular the respective additional valve devices. For example, the flow channel has a flow path connected to each additional piston, in particular a flow path connected to each additional valve device.

[0013] The flow channel extends in particular between the working chamber remote from the piston rod and the working chamber on the piston rod side to at least one additional piston. If the shock absorber comprises two additional pistons, the flow channel preferably extends from the first additional piston, in particular the first additional valve device, to the second additional piston, in particular the second additional valve device. The flow channel is preferably arranged hydraulically in parallel with the main piston, in particular in parallel with the flow channel in the main valve device or the main piston.

[0014] Each additional valve device preferably comprises a fluid inlet for the hydraulic fluid to enter the respective additional piston, in particular the respective additional valve device, each fluid inlet optionally being assigned a non-return valve, so that the fluid can only flow in one direction. The non-return valve is preferably arranged so as to completely close the fluid inlet and preferably comprises at least one spring washer to completely cover the respective fluid inlet. Each fluid inlet preferably allows flow only in the flow direction from the respective working chamber inwardly into the respective additional valve device. For example, the non-return valve of the fluid inlet is configured by means of an additional valve disc assembly.

[0015] Each additional valve device preferably comprises a fluid outlet for discharging hydraulic fluid from the corresponding additional valve device. Each fluid outlet is preferably provided with at least one outlet spring washer, which is arranged as a non-return valve, so that the fluid outlet can only flow in one direction.

[0016] The shock absorber further comprises an external damping valve device for damping the movement of the piston rod in the rebound phase and / or the compression phase. The damping valve device is preferably mounted outside the working piston, the inner tube and the outer tube.

[0017] According to a first embodiment, the main piston comprises a main valve device and / or a main flow channel, and the flow channel is arranged hydraulically in parallel with the main valve device and / or the main flow channel. Thus, a damping effect outside the main valve device of the main piston can be achieved by the additional piston and the additional valve device.

[0018] The working piston preferably comprises a main piston which is at least partially in fluid-tight cooperation with the damping cylinder, and at least one or two additional pistons. The main piston is preferably arranged between the additional pistons. For example, the additional piston does not have any circulation channel and / or valve device, and the hydraulic fluid cannot flow through the additional piston, or can only flow through the additional piston through the circulation channel. The additional piston is, for example, arranged at a certain distance from the damping cylinder, so that the fluid is allowed to flow between the additional piston and the inner wall of the damping cylinder. The additional piston is preferably installed coaxially with the piston rod and fixed in position. For example, one of the additional pistons, the first additional piston, is arranged in a working chamber close to one side of the piston rod and is located in the rebound direction relative to the main piston. The other additional piston, the second additional piston, is arranged in a working chamber away from the piston rod and is located in the compression direction relative to the main piston. The main piston is preferably arranged between the two additional pistons. The main piston and at least one or two additional pistons each preferably have a corresponding valve device.

[0019] The main valve device preferably connects the working chamber on the piston rod side with the working chamber away from the piston rod. The main valve device preferably comprises a main valve body and at least two main flow channels arranged in the main valve body, namely a first main flow channel and a second main flow channel. The main flow channels preferably extend from one end face of the working piston, in particular the end face of the main valve body, to the other opposite end face, and are arranged separately from each other, preferably isolated from each other in terms of fluid.

[0020] The main valve device preferably comprises at least two spring washer valves, which are respectively mounted on the end face of the main valve device, in particular the end face of the valve body.

[0021] The arrangement of the spring washer valve is particularly set so that it controls the flow path of only one main flow channel. Each main flow channel is preferably equipped with only one spring washer valve. The main valve device preferably comprises a first spring washer valve, which cooperates with the first main flow channel to determine the flow path of the hydraulic fluid through the main flow channel and preferably regulates the flow according to the flow rate.

[0022] Each spring washer valve preferably comprises at least one spring washer assembly. The spring washer assembly is preferably preloaded on a main valve seat arranged in the main valve body and abuts against the main valve seat. The spring washer assembly is preferably arranged on the respective main valve seat in such a way that it is lifted from the main valve seat only in the case of unidirectional flow in the corresponding main flow channel and completely or partially releases the flow cross section of the main flow channel.

[0023] For example, a sealing element, in particular a sealing ring, can be arranged in the circumferential direction around the main valve seat so that it bears against the inner wall of the damping cylinder in a fluid-tight manner.

[0024] According to another embodiment, the flow channel comprises a flow path for the hydraulic fluid to enter, which flow path leads to the first additional piston, and furthermore, the flow channel comprises a further flow path for the hydraulic fluid to enter the second additional piston. The flow path is arranged in the piston rod, for example, and preferably the flow channel is fluidically connected to the additional piston.

[0025] According to another embodiment, each additional valve device comprises a fluid inlet for hydraulic fluid to enter the additional valve device, and each additional piston comprises a fluid outlet for hydraulic fluid to be discharged from the additional piston, wherein the fluid inlet of the first additional valve device of the first additional piston is fluidically connected to the fluid outlet of the second additional piston through a circulation channel. The hydraulic fluid preferably flows into the two additional pistons, and in particular only through one additional piston valve. The additional piston valve is preferably arranged so that each valve only allows one-way flow, preferably only in the rebound or compression phase. Each fluid outlet is, for example, matched with an outlet spring washer assembly. The outlet spring washer assembly is preferably arranged to completely close the fluid outlet, and preferably comprises at least one spring washer, completely covering the corresponding fluid outlet. Each fluid outlet preferably only allows the flow direction to flow from the inside of the respective additional valve device to the outside into the respective working chamber, wherein the outlet spring washer assembly is preferably configured as a one-way valve.

[0026] According to another embodiment, each additional valve device comprises an additional valve body, an additional valve piston axially movable relative to the additional valve body, and an additional valve disc assembly cooperating with the additional valve piston, and the additional valve device further comprises a preload system for applying a preload force to the additional valve disc assembly, wherein the preload system comprises at least one pressure chamber with a variable volume. The variable volume pressure chamber in the preload system enables the preload force of the additional valve disc assembly to be set with the frequency, thereby achieving frequency-dependent damping.

[0027] The volume of the pressure chamber can preferably be increased or decreased, in particular depending on the hydraulic pressure present in the pressure chamber. The pressure chamber is preferably arranged to load the additional valve piston with an axial force, in particular when there is hydraulic pressure in the pressure chamber. The pressure chamber is arranged and configured in particular such that a change in its volume leads to a movement of the additional valve piston in the axial direction. The additional valve piston preferably bears against the pressure chamber at least directly or indirectly. The additional valve device comprises the preload system for applying an axial force to the additional valve piston. The preload system is preferably part of the respective additional piston and the respective additional valve device.

[0028] The additional valve device preferably has an additional valve body, which is preferably mounted on the piston rod in a fixed position. In particular, an axially movable additional valve piston is arranged in the additional valve body. The additional valve piston preferably abuts the additional valve body at least partially and is mounted in a manner that can be moved in the axial direction relative to the additional valve body and the piston rod. Preferably, a sealing element is arranged between the additional valve piston and the additional valve body for fluid sealing between them. The additional valve body is preferably a pot-shaped structure and is open in the axial direction of the outlet spring washer assembly. The additional valve piston is preferably accommodated in the pot-shaped additional valve body so as to be able to slide in the axial direction of the piston rod and the additional valve body. The additional valve body is preferably configured as a housing of the additional valve device, especially the additional piston. In particular, the additional valve body is a hollow cylindrical structure with a cover area facing the main piston, a hollow cylindrical side wall area and a bottom area away from the main piston. The additional valve piston preferably includes an additional valve seat and abuts against the additional valve disc assembly through it. The additional valve device also includes an additional valve disc assembly that cooperates with the additional valve piston. In particular, the additional valve disc assembly abuts against the additional valve piston directly or indirectly.

[0029] The additional valve disc assembly is preferably mounted so as to be axially movable relative to the additional valve body and / or the piston rod, and thus preferably axially movable together with the additional piston. At the same time, the additional valve disc assembly can also be fixedly mounted on the additional valve body and / or the piston rod. The additional valve piston can be a single-piece or multi-piece structure. In particular, the additional valve disc assembly directly or indirectly abuts against the additional valve piston. The additional valve disc assembly can be mounted, for example, on an additional valve seat on the additional valve piston or on the additional valve housing.

[0030] According to another embodiment, the preload system comprises an orifice for the hydraulic fluid to enter the pressure chamber. The orifice is preferably configured as an opening, in particular on the piston rod or an additional valve body. The orifice, in particular the cross-sectional area of ​​the orifice, enables the pressure chamber to be hydraulically filled at a predetermined speed depending on the hydraulic pressure or flow rate, thereby achieving a targeted damping force adjustment depending on the shock absorber excitation frequency.

[0031] According to a further embodiment, the preload system comprises a first pressure chamber and a second pressure chamber. Preferably, the volume of the first and / or second pressure chamber can be increased or decreased, in particular, it changes based on the hydraulic pressure in the respective pressure chamber. The first and / or second pressure chamber is preferably arranged to load the additional valve piston with an axial force, in particular when the respective pressure chamber is filled with hydraulic pressure. The first and / or second pressure chamber is particularly configured and arranged so that a change in its volume causes the additional valve piston to move in the axial direction. The additional valve piston preferably abuts at least directly or indirectly against one pressure chamber, so that at least one side of the additional valve piston defines the pressure chamber. In particular, the second pressure chamber directly abuts against the additional valve piston. The pressure chambers are preferably arranged separately from each other. The additional valve disc assembly can be loaded with a preload force via the additional valve piston, so that the additional valve disc assembly is preloaded onto the corresponding additional valve seat.

[0032] The preload system with two or more pressure chambers with variable volumes has the technical effect that the volumes of the pressure chambers change at different speeds under excitation at different frequencies, thereby achieving frequency-sensitive preload of the additional valve disc assembly.

[0033] According to another embodiment, the first pressure chamber and the second pressure chamber are hydraulically connected in series. The pressure chamber is preferably arranged to interact with the additional valve piston so that the additional valve piston is moved axially in the event of a pressure change in the pressure chamber. The pressure chamber is preferably against the side of the additional valve piston opposite to the additional valve disc assembly. In particular, the hydraulically effective surface area of ​​the additional piston on the side facing the pressure chamber is larger than the hydraulically effective surface area on the side facing the additional valve disc assembly. If the same pressure is present on both sides of the additional valve piston, i.e. at the pressure chamber and at the fluid inlet of the additional valve device, the additional valve piston is preferably offset in the direction of the additional valve disc assembly, in particular in the preload direction.

[0034] Under load, the second pressure chamber is preferably arranged downstream of the first pressure chamber, in particular directly adjacent to the additional valve piston. The pressure chambers in particular have different volumes, the first pressure chamber preferably having a smaller volume than the second pressure chamber. The pressure chambers of different volumes are connected in series to ensure a stepped distribution of the movement speed of the additional piston. Due to the series connection, the second pressure chamber only pushes the displacement of the additional piston after the first pressure chamber is filled.

[0035] The first pressure chamber is arranged, for example, to enable the additional valve piston to move within a first axial stroke range, the first axial stroke being driven by the force generated by the hydraulic pressure of the first pressure chamber; the second pressure chamber is arranged to enable the additional valve piston to move within a second axial stroke range, the second axial stroke range being driven by the force generated by the hydraulic pressure of the second pressure chamber. The first axial stroke range is a portion of the second axial stroke range, in particular a section thereof. The second axial stroke range is preferably the maximum axial displacement of the additional piston, in particular the complete axial displacement range of the additional piston. Different volumes of different pressure chambers can produce different axial displacements of the additional piston, so that the axial displacement of the additional piston is different in the low speed and high speed ranges of the working piston.

[0036] According to another embodiment, the pretensioning system comprises a first orifice for the hydraulic fluid to enter the first pressure chamber and a second orifice for the hydraulic fluid to enter the second pressure chamber. The second orifice is preferably arranged between the first and second pressure chambers. The first and second pressure chambers are directly connected to each other, for example, via the second orifice. The first and second orifices are preferably configured as inlets, in particular inlet openings, for the hydraulic fluid to enter the respective pressure chambers. The fluid inlet for the hydraulic fluid to enter the pretensioning system is preferably covered by a spring washer, which constitutes a one-way valve. In particular, the first orifice is configured as an opening in the spring washer. The advantage of filling the pressure chambers through the respectively corresponding orifices is that they can be filled separately, for example, filling the respective pressure chambers at different filling speeds. The first orifice is optionally configured as a flow opening in the flow channel, in particular when only one additional piston is provided.

[0037] According to another embodiment, the cross-sectional area of ​​the first orifice is larger than that of the second orifice. For example, the cross-sectional area of ​​the first orifice is approximately 2 to 10 times, preferably 3 to 6 times, and in particular 5 times that of the second orifice. The two orifices can optionally have the same size. For example, the first orifice is configured as a main flow channel in the main piston, or a cross-sectional reduction portion in the main flow channel of the main piston. For example, the main piston does not include a main valve device. The orifices have, for example, different cross-sectional areas. This ensures different filling speeds of the two pressure chambers. The larger first orifice can fill the first pressure chamber more quickly, resulting in a faster change in the volume of the first pressure chamber, so that the movement speed of the additional piston when filling the first pressure chamber is also higher than the speed when filling the second pressure chamber.

[0038] According to another embodiment, the preload system comprises a separating washer, which separates the first pressure chamber and the second pressure chamber from each other in terms of fluid. The separating washer is, for example, a separating spring washer.

[0039] According to a further embodiment, the second orifice is configured as an opening of a separating washer, in particular an opening in a separating spring washer, for fluid connection of the first and second pressure chambers. The first and second pressure chambers are preferably fluidically connected to each other only via the second orifice. Thus, a series connection of the two pressure chambers can be achieved and the pressure chambers can preferably be filled at different speeds.

[0040] The second pressure chamber is preferably arranged between the additional valve piston and the separation spring washer, while the first pressure chamber is arranged between the separation spring washer and the additional valve body or the main piston. The separation spring washer and the additional valve disc assembly are preferably arranged on both sides of the additional valve piston.

[0041] For example, the first and / or second orifice configured as an opening may be circular or slot-shaped. In particular, the separating spring washer has a plurality of openings, which are preferably arranged at the same radial spacing as the piston rod and together constitute the second orifice.

[0042] According to a further embodiment, the separating washer is axially movable relative to the additional valve body and the piston rod. According to a further embodiment, the separating spring washer bears against the additional valve piston and is preferably movable therewith. The axial mobility of the separating spring washer enables the volume of the first pressure chamber to change when the separating spring washer moves, in particular when the separating spring washer moves together with the additional valve piston, thereby achieving a simple coupling of the change in the volume of the first pressure chamber with the movement of the additional piston.

[0043] According to a further embodiment, the preloading system includes an axial stop for limiting the axial movement of the separating spring washer. The stop is preferably arranged in the additional valve body and is configured as a bearing surface, in particular, of the separating spring washer. The bearing surface is particularly spaced apart from the bottom area. The side area of ​​the additional valve body preferably includes an inner wall, which is configured as an axial sliding surface of the additional valve piston, along which the additional valve piston can slide. A cutout is preferably provided in the inner wall, which extends axially from one end pointing to the bottom area to the direction of the additional valve piston and opens at the bearing surface. The stop, in particular the bearing surface, preferably extends in a radial direction and is preferably configured as an axial stop for the separating spring washer. The stop is preferably configured and arranged to limit the axial movement of the separating spring washer, thereby limiting the volume increase of the first pressure chamber.

[0044] For example, the additional valve disc assembly can be fixed to the valve body. In particular, the additional valve disc assembly is connected to the piston rod in a fixed position and cannot move relative to the piston rod. It is also conceivable that the additional valve disc assembly is fixed to the additional valve piston.

[0045] In particular, the additional valve piston has a recess which at least partially forms the second pressure chamber. The recess preferably increases the effective hydraulic area of ​​the side of the additional valve piston facing the second pressure chamber.

[0046] According to a further embodiment, the separating washer is supported on the additional valve piston and can be moved together with it. It is also conceivable to connect the separating washer to the additional valve device in a fixed position. In this way, the volume of only one pressure chamber, namely the volume of the second pressure chamber, is variable. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The following text describes the present invention in more detail through multiple exemplary embodiments in conjunction with the accompanying drawings.

[0048] Figure 1 : A schematic diagram of a shock absorber according to an exemplary embodiment is shown, which is a longitudinal cross-sectional view.

[0049] Figure 2 : A schematic diagram showing a local detail of a shock absorber according to another exemplary embodiment, which is a longitudinal cross-sectional view.

[0050] Figure 3 : A schematic illustration of a partial detail of a shock absorber according to a further exemplary embodiment is shown in a longitudinal sectional view.

[0051] Figure 4 : A schematic illustration of a partial detail of a shock absorber without a main piston valve according to a further exemplary embodiment is shown in a longitudinal sectional view.

[0052] Figure 1 A shock absorber 10 is shown, wherein the shock absorber 10 is a single-tube shock absorber. It is also conceivable that the shock absorber is a multi-tube shock absorber, such as a double-tube shock absorber. The shock absorber 10 has a shock absorber cylinder 12, Figure 1 In the case of the monotube shock absorber shown, the shock absorber cylinder 12 forms the outer tube and forms the outer surface of the shock absorber 10 , in particular the outer shell.

[0053] The working piston 18 connected to the piston rod 20 is arranged in the damping cylinder 12 so that it can move in the damping cylinder 12, wherein the damping cylinder 12 is preferably configured as a guide for the working piston 18. The working piston 18 includes, for example, a valve device (in Figure 1 The working piston 18 divides the inner chamber of the damping cylinder 12 into a first working chamber 22 located on the piston rod side and a second working chamber 24 away from the piston rod.

[0054] The inner cavity of the damping cylinder 12 is fluid-sealed on the piston rod side by a sealing assembly. For example, on the opposite side of the sealing assembly, away from the end of the piston rod, the inner cavity is fluid-sealed by a separating piston to isolate it from an adjacent gas cavity. The gas cavity is arranged in the damping cylinder 12, and the separating piston is preferably axially movable in the damping cylinder 12.

[0055] It is also conceivable that the shock absorber is configured as a multi-tube shock absorber. In the case of a multi-tube shock absorber, an outer tube is coaxially arranged outside the shock absorber cylinder 12. A balance chamber is formed between the outer tube and the inner tube, which balance chamber is at least partially filled with hydraulic fluid. For example, the balance chamber is partially filled with gas. On the opposite side of the sealing assembly, i.e. the end away from the piston rod, the inner chamber of the shock absorber cylinder 12 of the multi-tube shock absorber is preferably fluid-sealed by a bottom part. A bottom valve, in particular arranged on the bottom part at the end of the inner tube away from the piston rod, can be mounted on the bottom part, for example. The second working chamber 24 is preferably fluidically connected to the balance chamber via a bottom valve.

[0056] The working piston 18 comprises a main piston 14, which at least partially rests in a fluid-tight manner on the damping cylinder 12. The working piston 18 also comprises two additional pistons 26 and 28, namely a first additional piston 26 and a second additional piston 28. It is also conceivable that the working piston has only one additional piston. Figure 1 and Figure 2A shock absorber with two additional pistons is shown only as an example. The additional pistons 26 and 28 are arranged at a certain distance from the inner wall of the shock absorber cylinder 12 so that a fluid flow can be achieved between the additional pistons 26 and 28 and the inner wall of the shock absorber cylinder 12. The additional pistons 26 and 28 are preferably mounted on the piston rod 20 in a fixed manner, in particular coaxially with the main piston 14. For example, the first additional piston 26 is arranged in the working chamber 22 on the piston rod side and is located in the rebound direction Z relative to the main piston 26. For example, the second additional piston 28 is arranged in the working chamber 24 away from the piston rod and is located in the compression direction D relative to the main piston 26. The main piston 14 and the additional pistons 26, 28 are preferably each equipped with a valve device. The main piston 14, for example, includes a main valve device 16, and the additional pistons 26 and 28 are equipped with additional valve devices 46 and 48, respectively.

[0057] Figure 2 A detailed view of a working piston 18 is shown, comprising a main piston 14 and additional pistons 26, 28. The main piston 14 comprises a main valve device 16. The main valve device 16 connects the working chamber 22 on the piston rod side to the working chamber 24 remote from the piston rod. The main valve device 16 comprises a main valve body 30, and at least two main flow channels 32 and 34, namely a first main flow channel 32 and a second main flow channel 34, arranged in the main valve body 30. The main flow channels 32, 34 preferably each extend from one end face of the working piston 18, in particular an end face of the main valve body 30, to an opposite end face, and are mutually independent, preferably arranged fluidically isolated from each other.

[0058] The main valve device 16 includes at least two spring washer valves 36 and 38, which are respectively mounted on the end faces of the main valve device 16, in particular, on the end faces of the valve body 30. The spring washer valves 36, 38 are arranged to control the flow path of only one main flow channel 32, 34. Each main flow channel 32, 34 is preferably equipped with only one spring washer valve 36 or 38. The main valve device 16 preferably includes a first spring washer valve 36, which cooperates with the first main flow channel 32 to define the flow path of the hydraulic fluid through the main flow channel 32, and preferably adjusts the flow path according to the flow rate.

[0059] Each spring washer valve 36, 38 preferably includes at least one spring washer assembly. Each spring washer assembly is composed of a plurality of spring washers and is pre-tightened on the main valve seats 40 and 42 arranged in the main valve body 30 and abuts against the main valve seats. The spring washer assembly is preferably arranged on the corresponding main valve seats 40 and 42, and is lifted from the main valve seats 40 or 42 only in the case of unidirectional flow of the corresponding main flow channel 32 or 34, and completely or partially releases the flow cross section of the main flow channel 32 or 34. The spring washer valves 36, 38 are preferably configured as one-way valves to ensure that the spring washer assembly is not lifted from the corresponding main valve seats 40, 42 when the fluid flows in the opposite direction. When the spring washer assembly of each spring washer valve 36, 38 is lifted from the corresponding main valve seat 40, 42, the corresponding spring washer valve 36 or 38 is in an open state. When the spring washer assembly abuts against the corresponding main valve seat 40, 42, the corresponding spring washer valve 36, 38 is in a closed state.

[0060] When the piston rod 20 moves in the compression direction D, the first main flow channel 32 flows in the rebound direction Z, and the first spring washer valve 36 is opened in this flow condition. Therefore, the first spring washer valve 36 is also called a compression stage valve. When the piston rod 20 moves in the rebound direction Z, the second main flow channel 34 flows in the compression direction D, and the second spring washer valve 38 is opened in this flow condition. Therefore, the second spring washer valve 38 is also called a rebound stage valve. The elastic stiffness, number and size of the spring washer preferably determine the damping characteristics of the piston in the rebound or compression direction.

[0061] The sealing element 44 may be mounted, for example, on the circumference of the main valve seat 30 , and the sealing element 44 preferably abuts against the inner wall of the damping cylinder 12 in a fluid-tight manner.

[0062] The additional pistons 26 and 28 are each equipped with additional valve devices 46 and 48, and preferably have substantially the same structure. The additional valve devices 46 and 48 are preferably arranged in the respective additional pistons 26 and 28. The piston rod 20 is, for example, a two-part structure, or may be an integral structure. A circulation channel 50 is preferably configured in the piston rod 20, and the additional pistons 26 and 28, especially the additional valve devices 46 and 48, are fluidically connected to each other. The working chamber 22 on the piston rod side and the working chamber 24 away from the piston rod are preferably connected to each other through the circulation channel 50 and the additional pistons 26 and 28, especially the additional valve devices 46 and 48. The circulation channel 50 is preferably configured as an annular space, extending in the axial direction of the piston rod 20. The circulation channel 50 can be, for example, configured in the piston rod 20, or configured between the piston rod 20 and the working piston 18 connected to the piston rod 20. The circulation channel 50 preferably has a plurality of circulation paths 66 and 68 for guiding the hydraulic fluid to the respective additional pistons 26 and 28.

[0063] The flow channel 50 preferably extends in the flow direction of the hydraulic fluid from the first additional piston 26, in particular the first additional valve device 46, to the second additional piston 28, in particular the second additional valve device 48. The flow channel 50 is preferably arranged hydraulically parallel to the main piston 14, in particular parallel to the main valve device 16.

[0064] Each additional valve device 46, 48 is provided with a fluid inlet 52, 54 for hydraulic fluid so as to introduce the hydraulic fluid into the respective additional valve device 46, 48. Each additional piston 26, 28 is provided with a liquid outlet 58, 60 for discharging the hydraulic fluid from the respective additional piston 26, 28, in particular from the respective additional valve device 46, 48. Each fluid outlet 58, 60 is preferably equipped with an outlet spring washer 62, 64 so that the fluid outlet 58, 60 can only achieve one-way flow. The outlet spring washer 62, 64 preferably includes at least one spring washer, which completely covers the respective fluid outlet 58, 60. Each fluid outlet 58, 60 preferably only allows the flow of liquid from the interior of the respective additional piston 26, 28 to the outside into the respective working chamber 22, 24, and is preferably configured as a one-way valve.

[0065] The flow channel 50 comprises, for example, at least two flow paths 66, 68. For example, each additional piston 26, 28 is fluidically connected to the flow channel 50 via at least one flow path or exactly one flow path 66, 68. For example, the fluid inlet 52, 54 of each additional valve device 46, 48 of the additional piston 26, 28 is connected to the flow channel 50 via one flow path 66, 68 and is fluidically connected to the fluid outlet 58, 60 of the other additional piston 26, 28. For example, the fluid inlet 52 of the first additional valve device 46 of the first additional piston 26 is fluidically connected to the fluid outlet 58 of the second additional piston 28 via the flow channel 50. In particular, the fluid inlet 54 of the second additional valve device 48 of the second additional piston 28 is connected to the fluid outlet 60 of the first additional piston 26 via the flow channel 50.

[0066] Figure 2The flow path when the piston rod 20 moves in the compression direction D is shown, marked with dashed arrows. During operation of the shock absorber 10, when the working piston 18 moves in the compression direction D, the hydraulic fluid flows through the main piston 14 in the rebound direction Z and opens the first spring washer valve 36 when the hydraulic pressure exceeds the opening pressure of the valve. In parallel with the flow into the main piston 14, the hydraulic fluid flows through the fluid inlet 54 of the second additional valve device 48 and opens the second additional valve device 48 when the opening pressure of the additional spring washer assembly 70 is exceeded. The hydraulic fluid then flows through the flow path 68 into the flow channel 50 of the piston rod 20 and from the flow path 66 into the fluid outlet 60 of the first additional piston 26. When the opening pressure of the outlet spring washer 64 is exceeded, the hydraulic fluid flows from the first additional piston 26 into the working chamber 22 on the piston rod side. When the piston rod 20 moves in the rebound direction Z, the first additional valve device 46 and the main valve device 16 are opened accordingly.

[0067] Figure 3 A detailed illustration of the second additional valve device 48 is shown. The second additional valve device 48 preferably has a substantially identical structure to the first additional valve device 46, so that only one additional valve device 46 or 48 is described below as an example. The additional valve devices 46, 48 comprise an additional valve disc assembly 70, for example, which is composed of at least one or more spring washers. The additional valve disc assembly 70 is preferably connected downstream of the fluid inlet 58, 60 of the additional valve devices 46, 48 in the flow direction of the hydraulic fluid. In particular, the additional valve disc assembly 70 can be loaded with a preload. In the closed position, the additional valve disc assembly 70 preferably abuts against the additional valve seat 84, in particular, is preloaded on the valve seat 84 under the action of the preload. In the open position of the additional valve devices 46, 48, the additional valve disc assembly 70 is lifted from the additional valve seat 84.

[0068] The additional valve device 46, 48 comprises an additional valve body 74, which is preferably mounted on the piston rod 20 in a fixed position. For example, the additional valve body 74 constitutes the housing of the additional valve device 46, 48, in particular the housing of the additional piston 26, 28. In particular, the additional valve body 74 is hollow cylindrical, with a cover area facing the main piston 14, a hollow cylindrical side wall area, and a bottom area away from the main piston 14. For example, an axially movable additional valve piston 76 is arranged in the additional valve body 74. The additional valve piston 76 is preferably at least partially against and attached to the additional valve body 74 so as to be movable relative to the additional valve body 74 and the piston rod 20 in the axial direction.

[0069] The additional valve piston 76 preferably comprises an additional valve seat 84 and abuts against the valve seat and the additional valve disc assembly 70. For example, the diameter of the additional valve piston 76 gradually decreases in the direction towards the additional valve seat. The movement of the additional valve piston 76 in the axial direction changes the preload of the additional valve disc assembly 70 on the valve seat. The additional valve disc assembly 70 is, for example, fixed to the additional valve body 74, in particular connected to the additional valve body in a supporting manner. The additional valve disc assembly 70 comprises, for example, three spring washers abutting against each other, wherein the lower spring washer close to the valve seat has the largest diameter, while the remaining spring washers have smaller diameters.

[0070] The additional valve device 46, 48 preferably comprises a preload system 56 for applying a preload force to the additional valve disk assembly 70, in particular an axial force to the additional valve piston 76. The preload system 56 is preferably a part of the additional piston 26, 28 and the additional valve device 46, 48. The preload system 56 preferably comprises a first pressure chamber 72 and a second pressure chamber 73, which are hydraulically connected in series. The pressure chambers 72, 73 are arranged in such a way that they can interact with the additional valve piston 76, so that when the pressure in the pressure chambers 72, 73 changes, the additional valve piston 76 moves axially.

[0071] The pressure chambers 72, 73 are preferably arranged on the side of the additional valve piston 76 opposite to the additional spring washer assembly 70. In addition, the preload system 56 comprises, for example, two openings 80, 82, which serve as inlets for the hydraulic fluid to enter the respective pressure chambers 72, 73. The first opening 80 is preferably configured and arranged as an inlet for the hydraulic fluid to enter the first pressure chamber 72. The preload system 56 has, for example, a fluid inlet 94, which is configured as a hole on the additional valve body 74, in particular arranged on the side away from the main piston 14. The fluid inlet 74 is preferably covered by a spring washer 96, which constitutes a non-return valve, in particular only allowing the hydraulic fluid to flow from the additional piston 26, 28 (in particular the preload system 56) into the respective working chamber 22, 24. The first opening 80 is configured, for example, as an opening on the spring washer.

[0072] The first pressure chamber 72 and the second pressure chamber 73 are separated from each other by a separating spring washer 78, so that the first pressure chamber 72 and the second pressure chamber 73 are respectively against the spring washer 78. The second orifice 82 is preferably configured as an opening on the spring washer 78 for introducing the hydraulic fluid from the first pressure chamber 72 to the second pressure chamber 73. The separating spring washer 78 is, for example, against the additional valve piston 76. In particular, the separating spring washer 78 is mounted in an axially movable manner relative to the piston rod 20 and the additional valve body 74. The separating spring washer 78 is preferably movable together with the additional valve piston 76. The cross-sectional area of ​​the first orifice 80 is preferably larger than the cross-sectional area of ​​the second orifice 82. The first pressure chamber 72 is, for example, configured between the separating spring washer 78 and the additional valve body 74, while the second pressure chamber 73 is preferably configured between the separating spring washer 78 and the additional valve piston 76.

[0073] In addition, the preload system 56 further comprises an axial stop 90 for limiting the axial movement of the separation spring washer 78. The axial stop 90 is, for example, arranged in the additional valve body 74, in particular as a radial stop surface for contacting and in particular accommodating the separation spring washer 78. The stop 90 preferably limits the volume of the first pressure chamber 72, in particular limits the increase in its volume.

[0074] The first and second pressure chambers 72, 73 in the preload system 56 of each additional piston 26, 28 are preferably only fluidically connected to the respective working chamber 22, 24, i.e. the working chamber in which the additional piston 26, 28 is located. The pressure chambers 72, 73 are not fluidically connected to the two working chambers 22, 24. The additional valve piston 76 has, for example, a recess 92 which at least partially forms the second pressure chamber 73. The separating spring washer 78 and the additional valve disk assembly 70 are preferably arranged on opposite sides of the additional valve piston 76.

[0075] During operation of the shock absorber 10, when the piston rod 20 is excited in the compression direction D, for example at low speed, the first pressure chamber 72 is first filled with hydraulic fluid through the first orifice 80. The hydraulic fluid flows from the first pressure chamber 72 into the second pressure chamber 73 through the second orifice 82 and gradually fills the second pressure chamber 73. Since the cross-sectional area of ​​the second orifice 82 is smaller than the first orifice 80, the hydraulic fluid fills the second pressure chamber 73 more slowly. The increased hydraulic pressure in the first pressure chamber 72 causes the separating spring washer 78 and the additional valve piston 76 abutting against it to move in the axial direction, thereby increasing the volume of the first pressure chamber 72. When the volume of the first pressure chamber 72 increases, the separating spring washer 78 moves to the stop 90, at which time the separating spring washer 78 and the additional valve piston 76 move together at a first speed. After reaching the stop 90 and the separating spring washer 78 contacting it, a further increase in the volume of the first pressure chamber 72 is no longer possible. Since the opening of the second orifice 82 is small, the pressure in the second pressure chamber 73 rises slowly, so the volume of the second pressure chamber 73 increases slowly, resulting in the axial movement of the additional piston 76 at a lower speed. In particular, after the separation spring washer 78 contacts the stopper 90, the additional piston 76 moves at a second speed that is lower than the first speed. This design ensures that the preload of the additional valve disc assembly 70 is frequency-sensitively adjusted, especially at lower piston speeds. High-frequency excitation causes the additional valve piston 76 to move at a first speed, while low-frequency excitation causes the additional valve piston 76 to move first at the first speed and then at the second speed, thereby achieving higher damping at low frequencies, especially the preload effect on the additional valve disc assembly 70.

[0076] During operation of the shock absorber, when excited in the compression direction D, the hydraulic fluid also flows into the fluid inlet 52, 54 of the additional valve device 46, 48, and the additional valve device 46, 48 will open if the hydraulic pressure exceeds the opening pressure of the preferably preloaded additional valve disk assembly 70. The hydraulic fluid preferably flows through the additional valve device 46, 48 into the flow channel 50 and then through the fluid outlet 58, 60 of the opposite additional piston 26, 28 to the opposite working chamber 22, 24, in particular to the low-pressure chamber.

[0077] Figure 4 Another exemplary embodiment is shown, which is generally similar to Figures 1 to 3 , but with Figures 1 to 3 In contrast, the main piston 14 does not contain the main valve device 16 . The main piston 14 contains only the main through-channels 32 , 34 . The damping of the hydraulic fluid is preferably realized only via the additional valve devices 46 , 48 , which are connected to one another via the through-channel 50 .

[0078] exist Figure 4 In the exemplary embodiment of the additional valve piston 76, for example, a two-part structure is provided, wherein the region abutting against the additional valve disc assembly 70 is configured as an annular disc structure. It is also conceivable that the additional valve piston comprises more than two parts, which are combined and can be moved relative to the additional valve housing 74. The additional valve seat 88 is, for example, arranged in the additional valve housing 74, so that in the closed position, the additional valve disc assembly 70 abuts against the valve seat 88 of the additional valve housing 74. The additional valve disc assembly 70 is, for example, mounted in an axially movable manner, preferably moving together with the additional valve piston.

[0079] The pressure chambers 72, 73 are arranged, for example, on the side of each additional piston 26, 28 facing the main piston 14. The hydraulic fluid inlet 54 of the additional valve device 46, 48 is arranged, for example, on the side of the additional piston 26, 28 away from the main piston 14, and is preferably covered by a spring washer as a non-return valve. The non-return valve is arranged in such a way that the hydraulic fluid is prevented from flowing from the additional piston 26, 28, especially the additional valve device 46, 48, into the respective working chamber 22.

[0080] The main through-channel 32, 34 is configured, for example, as a first opening 80, which serves as an inlet for the hydraulic fluid to enter the first pressure chamber 72. The main through-channel 34 preferably has a cross-sectional constriction region, which forms the first opening 80.

[0081] exist Figure 4During operation of the shock absorber 10 shown, in particular when the piston rod moves in the compression direction D, the hydraulic fluid enters the second additional piston 48 through the fluid inlet 54 and then into the flow channel 50 and then into the first additional valve device 46 of the first additional piston 26. If the opening pressure of the additional valve disc assembly 70 of the first additional valve device 46 is exceeded, the valve device will open and the hydraulic fluid will flow out into the low-pressure chamber. At the same time, the hydraulic fluid flows into the first pressure chamber 72 through the second main flow channel 34 and then into the second pressure chamber 73, thereby Figure 3 The additional valve disc assembly 70 is pre-tightened in the manner described.

[0082] List of Reference Numerals

[0083] 10: Shock absorber

[0084] 12: Vibration damping cylinder

[0085] 14: Main piston

[0086] 16: Main valve device

[0087] 18: Working piston

[0088] 20: Piston rod

[0089] 22: Working chamber on the piston rod side

[0090] 24: Working chamber away from the piston rod

[0091] 26: First additional piston

[0092] 28: Second additional piston

[0093] 30: Main valve body

[0094] 32: First main flow channel

[0095] 34: Second main flow channel

[0096] 36: First spring washer valve

[0097] 38: Second spring washer valve

[0098] 40: First main valve seat

[0099] 42: Second main valve seat

[0100] 44: Sealing element

[0101] 46: First additional valve device

[0102] 48: Second additional valve device

[0103] 50: Distribution channels

[0104] 52,54: Fluid inlet

[0105] 56: Preload system

[0106] 58,60: Fluid outlet

[0107] 62,64: Export spring washer

[0108] 66,68: Circulation path

[0109] 70: Additional valve disc assembly

[0110] 72: First pressure chamber

[0111] 73: Second pressure chamber

[0112] 74: Additional valve body

[0113] 76: Additional valve piston

[0114] 78: Separator spring washer

[0115] 80: First orifice

[0116] 82: Second orifice

[0117] 84: Additional valve seat

[0118] 86: Spacer washer

[0119] 88: Valve seat

[0120] 90: Stopper

[0121] 92: Groove

[0122] 94: Fluid inlet

[0123] 96: Spring washer

Claims

1. A motor vehicle shock absorber (10), comprising The shock absorber tube (12) and A working piston (18) is arranged in the shock absorber tube (12) in an axially movable manner and divides the internal space of the shock absorber tube (12) into a working space located on one side (22) of the piston rod and a working space away from the piston rod (24). Features The working piston (18) comprises a main piston (14), a first auxiliary piston (26) and a second auxiliary piston (28). The additional pistons (26, 28) each comprise an additional valve device (46, 48), and the additional pistons (26, 28) are fluidically connected to each other via a flow channel (50).

2. The shock absorber (10) according to claim 1, wherein the main piston (14) comprises a main valve device (16) and / or a main flow channel (32, 34), and the flow channel (50) is arranged hydraulically in parallel with the main valve device (16) and / or the main flow channel (32, 34).

3. A shock absorber (10) according to any one of the preceding claims, wherein the flow channel (50) comprises a flow path (66) leading to a first additional piston (26) for a hydraulic fluid inlet, and the flow channel (50) further comprises a flow path (68) leading to a second additional piston (28) for a hydraulic fluid inlet.

4. A shock absorber (10) according to any of the preceding claims, wherein each additional valve device (46, 48) includes a fluid inlet (52, 54) for the inflow of hydraulic fluid into the additional valve device (46, 48), wherein each additional piston (26, 28) includes a fluid outlet (58, 60) for the outflow of hydraulic fluid from the additional valve device (46, 48); wherein the fluid inlet (52, 54) of the first additional valve device (46) is fluidically connected to the fluid outlet (60) of the second additional piston (28) via the flow channel (50).

5. The shock absorber (10) according to one of the preceding claims, the additional valve devices (46, 48) each comprising: an additional valve body (74) and an additional valve piston (76), the additional valve piston (76) being axially movable relative to the additional valve body (74), and an additional valve disc assembly (70) interacting with the additional valve piston (76), The additional valve device (46, 48) comprises a preload system (56) for loading the additional valve disc assembly (70) with a preload force, and the preload system (56) comprises at least one pressure chamber (72, 73) with a variable volume.

6. The shock absorber (10) of claim 5, wherein the preload system (56) comprises orifices (80, 82) for the inflow of hydraulic fluid into the pressure chambers (72, 73).

7. The shock absorber (10) according to any one of claims 5 or 6, wherein the preload system (56) comprises a first pressure chamber (72) and a second pressure chamber (73).

8. The shock absorber (10) according to claim 7, wherein the first pressure chamber (72) and the second pressure chamber (73) are hydraulically connected in series with each other.

9. The shock absorber (10) according to any one of claims 7 or 8, wherein the preload system (56) comprises a first orifice (80) for inputting hydraulic fluid into the first pressure chamber (72) and a second orifice (82) for inputting hydraulic fluid into the second pressure chamber (73).

10. The vibration absorber (10) of claim 9, wherein the first aperture (80) has a larger cross-sectional area than the second aperture (82).

11. The shock absorber (10) according to any one of claims 7 to 10, wherein the preload system (56) comprises a separation washer (78) separating the first pressure chamber (73a) from the second pressure chamber (73b).

12. The shock absorber (10) according to claim 11, wherein the second orifice (82) is configured as an opening in a separation gasket (78) for fluid connection of the first and second pressure chambers (72, 73).

13. The vibration absorber (10) according to any one of claims 11 or 12, wherein the separating washer (78) is attached axially movably relative to the additional valve body (74).

14. The vibration absorber (10) of claim 13, wherein the preload system (56) includes an axial stop (90) for limiting axial movement of the spacer washer (78).

15. The shock absorber (10) according to one of claims 11 to 14, wherein the separating washer (78) bears against the additional valve piston (76).

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