Vibration damper for motor vehicle

Abstract

The invention relates to a damper (10) for a motor vehicle, comprising a damper cylinder (12) and a working piston (18). The working piston (18) is arranged in the damper cylinder (12) in an axially movable manner and divides the interior of the damper cylinder (12) into a working space (22) on the side close to the piston rod and a working space (24) on the side away from the piston rod, the working piston (18) comprises a main piston (14) and at least one auxiliary piston (26, 28), the auxiliary piston (26, 28) has an auxiliary valve device (46, 48), and the auxiliary valve device (46, 48) is arranged in the working space (22) on the side close to the piston rod and the working space (24) on the side away from the piston rod. The auxiliary valve device is in fluid connection with a working space (22, 24) of the damper cylinder (12) through a flow channel (50); the auxiliary valve device (46, 48) comprises an auxiliary valve body (74) and an auxiliary valve piston (76) which can axially move relative to the valve body, and an auxiliary valve disc group (70) which interacts with the auxiliary valve piston (76); wherein the auxiliary valve device (46, 48) has a preloading system (56) for applying a preloading force to the auxiliary valve disk group (70), and the preloading system (56) comprises a first pressure chamber (72) and a second pressure chamber (73) having variable volumes.

Description

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

[0002] For example, shock absorbers with a frequency-sensitive damping system from DE 10 2016 208 845A1 are known. Known shock absorbers with a frequency-sensitive damping system are typically used in the extension phase or the compression phase. Known shock absorbers with a frequency-sensitive damping system generally exhibit a rather sluggish damping force adjustment in the low-speed range or the low damping force range. Therefore, it is desirable to provide frequency-dependent damping of the shock absorber at low excitation speeds. In particular, the aim is to achieve high damping at low frequencies (e.g., during cornering or braking), while achieving less damping at high frequencies (e.g., when driving on a cobblestone road).

[0003] Based on this, the object of the present invention is to provide a shock absorber with a frequency-sensitive damping system that allows frequency-sensitive damping force adjustment even in the low-speed or low damping force range.

[0004] According to the invention, this object is achieved by a device having the features of independent claim 1. Advantageous further developments are described in the dependent claims.

[0005] According to a first aspect, a shock absorber for a motor vehicle comprises: a shock absorber cylinder and a working piston, which is arranged to be axially movable within the shock absorber cylinder and divides the interior of the shock absorber cylinder into a working space on the piston rod side and a working space remote from the piston rod side, wherein the working piston has a main piston and at least one auxiliary piston. The auxiliary piston has an auxiliary valve device, which is fluidly connected to at least one working space of the shock absorber cylinder via a fluid passage, wherein the auxiliary valve device includes an auxiliary valve body and an auxiliary valve piston axially movable relative to the auxiliary valve body. The auxiliary valve device further includes an auxiliary valve disk set, which interacts with the auxiliary valve piston. In particular, the auxiliary valve disk set is directly or indirectly supported on the auxiliary valve piston. The auxiliary valve device has a preloading system for applying a preloading force to the auxiliary valve disk set, wherein the preloading system includes a first pressure chamber and a second pressure chamber, and the volume of each pressure chamber is variable.

[0006] The volume of the first and / or second pressure chamber is preferably capable of increasing or decreasing, particularly varying according to the prevailing hydraulic pressure in the respective pressure chamber. The first and / or second pressure chamber is preferably arranged to exert an axial force on the auxiliary valve piston, particularly when the respective pressure chamber is subjected to hydraulic pressure. In particular, the arrangement and design of the first pressure chamber and / or the second pressure chamber are such that a change in its volume causes the auxiliary valve piston to move in the axial direction. The auxiliary valve piston is preferably supported directly or indirectly on at least one pressure chamber such that at least one side of the auxiliary valve piston defines the pressure chamber. In particular, the second pressure chamber is preferably supported directly on the auxiliary valve piston. The pressure chambers are preferably arranged independently of each other. The auxiliary valve disc assembly can preferably be preloaded by the auxiliary valve piston such that the auxiliary valve disc assembly pre-tightens the corresponding auxiliary valve seat.

[0007] The technical effect of a preloading system having two or more pressure chambers with variable volumes is that, under excitation at different frequencies, the volume change rates of the respective pressure chambers are different, thereby achieving frequency-sensitive preloading of the auxiliary valve disc assembly.

[0008] For example, the shock absorber can be a mono-tube or multi-tube shock absorber. For example, a multi-tube shock absorber of a vehicle includes an outer tube and an inner tube coaxially arranged therewith, wherein a compensation space for accommodating hydraulic fluid is formed between the outer tube and the inner tube, and includes a working piston that is connected to a piston rod and arranged to be able to move back and forth within the inner tube, wherein the interior of the inner tube is divided by the working piston into a first working space on the side close to the piston rod and a second working space on the side away from the piston rod. The compensation space is preferably at least partially filled with gas, particularly at the upper end. The outer tube preferably at least partially forms the housing of the shock absorber. The inner surface of the inner tube is preferably designed as a guiding device for the working piston. The working piston preferably has a valve device through which the first and second working spaces communicate with each other. In the case of a mono-tube shock absorber, the outer tube is preferably not provided. In this case, the inner tube is called a shock absorber cylinder and houses the piston rod and the working piston as described above.

[0009] In the case of a multi-tube or mono-tube shock absorber, the shock absorber particularly includes a sealing assembly that is provided and arranged on the piston rod side to fluid-tightly 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. At the end of the sealing assembly on the opposite side, away from the piston rod, the compensation space and the second working space are preferably fluid-connected through a bottom valve. The compensation space is preferably fluid-connected to the first or second working space through an opening in the inner tube. For example, the compensation space is connected to the inner tube through the bottom valve.

[0010] In the case of a single-tube shock absorber, the shock absorber particularly includes a closure assembly which is constructed and arranged on the piston rod side to fluid-tightly seal the inner cavity of the shock absorber cylinder. The end of the shock absorber cylinder on the piston rod side is preferably fixed to the closure assembly. On the opposite side of the closure assembly, i.e., the end remote from the piston rod, the inner cavity of the shock absorber cylinder is preferably fluid-sealed by an axially movable sealing element. The sealing element preferably separates the gas space adjacent to it from the working chamber filled with hydraulic fluid in the axial direction.

[0011] In the following description, the term "shock absorber" should be understood to include multi-tube shock absorbers and single-tube shock absorbers, where the shock absorber cylinder is the inner tube of the multi-tube shock absorber.

[0012] The working piston preferably includes a main piston which at least partially fluid-tightly abuts against the shock absorber cylinder, and includes at least one or two auxiliary pistons. The auxiliary pistons are arranged at intervals from the shock absorber cylinder, for example, allowing fluid to flow between the auxiliary pistons and the inner wall of the shock absorber cylinder. The auxiliary pistons are preferably coaxially mounted on the piston rod and are preferably fixed in position. For example, one of the auxiliary pistons, i.e., the first auxiliary piston, is arranged in the working space near the piston rod side and is in the tensile direction relative to the main piston. The other auxiliary piston, i.e., the second auxiliary piston, is arranged in the working space on the side remote from the piston rod, for example, and is in the compression direction relative to the main piston. The main piston is preferably located between the two auxiliary pistons. The main piston and at least one or two auxiliary pistons preferably each have their own valve means.

[0013] For example, a flow passage is formed in the piston rod for fluid-connecting the auxiliary valve means of the respective auxiliary pistons. The working space on the piston rod side and the working space on the side remote from the piston rod are preferably fluid-connected through the flow passage and the auxiliary valve means. In particular, the flow passage is mainly designed as an annular space and extends axially within the piston rod. The flow passage preferably has a plurality of flow passages for delivering hydraulic fluid to the respective auxiliary pistons, in particular to the respective auxiliary valve means. For example, the flow passage has flow paths leading to each auxiliary piston, in particular to the respective auxiliary valve means.

[0014] In particular, the flow passage extends to at least one auxiliary piston between the working space on the side remote from the piston rod and the working space on the side near the piston rod. If the shock absorber has two auxiliary pistons, the flow passage preferably extends from the first auxiliary piston, in particular the first auxiliary valve means, to the second auxiliary piston, in particular the second auxiliary valve means. The flow passage is preferably arranged hydraulically in parallel with the main piston, in particular the main valve means.

[0015] Each auxiliary valve device preferably has a fluid inlet for allowing hydraulic fluid to enter the respective auxiliary piston, especially the respective auxiliary valve device. Each fluid inlet is optionally equipped with a check valve to ensure that the fluid inlet allows flow only in one direction. The check valve is preferably arranged to completely close the fluid inlet and preferably includes at least one spring disc, which preferably completely covers the respective fluid inlet. Each fluid inlet preferably allows fluid to flow only from the respective working space into the respective auxiliary valve device. For example, the check valve of the fluid inlet is formed by a set of auxiliary valve discs.

[0016] Each auxiliary valve device preferably has a fluid outlet for allowing hydraulic fluid to flow out of the respective auxiliary valve device. Each fluid outlet is preferably equipped with at least one outlet spring disc designed as a check valve, so that the fluid outlet allows only one-way flow.

[0017] The auxiliary valve device preferably has an auxiliary valve body, preferably mounted at a fixed position on the piston rod. In particular, an axially movable auxiliary valve piston is arranged in the auxiliary valve body. The auxiliary valve piston is preferably at least partially supported on the auxiliary valve body and is mounted in an axially movable manner relative to the auxiliary valve body and the piston rod. A sealing element is preferably installed between the auxiliary valve piston and the auxiliary valve body to make the fluid seal between them. The auxiliary valve body is preferably designed as a cup-shaped structure and is open in the axial direction of the set of outlet spring discs. The auxiliary valve piston is preferably received in the cup-shaped auxiliary valve body so as to slide axially on the piston rod and the auxiliary valve body. The auxiliary valve body preferably forms the housing of the auxiliary valve device, especially the housing of the auxiliary piston. In particular, the auxiliary valve body is in the form of a hollow cylinder with a top region facing the main piston, a side region being a hollow cylinder, and a bottom region facing away from the main piston. The auxiliary valve piston preferably includes an auxiliary valve seat and is supported on the set of auxiliary valve discs through the auxiliary valve seat.

[0018] The auxiliary valve device includes a preloading system for applying an axial force to the auxiliary valve piston. The preloading system is preferably part of the respective auxiliary piston and auxiliary valve device. For example, the first pressure chamber and the second pressure chamber are connected in series hydraulically. The pressure chambers are preferably arranged to interact with the auxiliary valve piston so that when the pressure in the pressure chambers changes, the auxiliary valve piston moves axially. The pressure chambers are preferably located on the opposite side of the set of auxiliary valve discs. In particular, the hydraulically effective area of the auxiliary piston on the side facing the pressure chambers is larger than its hydraulically effective area on the side facing the set of auxiliary valve discs. If the same pressure is applied on both sides of the auxiliary valve piston, especially at the pressure chambers and the fluid inlet flowing into the auxiliary valve device, the auxiliary valve piston preferably deflects in the direction of the set of auxiliary valve discs, especially in the preloading direction.

[0019] The auxiliary valve disc group is preferably installed to be axially movable relative to the auxiliary valve body and / or the piston rod, and thus preferably moves axially together with the auxiliary valve piston. The auxiliary valve disc group can also be fixedly installed on the auxiliary valve body and / or the piston rod. For example, the auxiliary valve piston can be of a single-component or multi-component design. In particular, the auxiliary valve disc group is directly or indirectly supported on the auxiliary valve piston. The auxiliary valve disc group is supported, for example, on an auxiliary valve seat, which can be formed, for example, on the auxiliary valve piston or the auxiliary valve housing.

[0020] The shock absorber includes, for example, an external damping valve device for damping the movement of the piston rod during the extension phase and / or the compression phase. The damping valve device is preferably installed outside the working piston, the inner tube, and the outer tube.

[0021] In the first embodiment, the first and second pressure chambers are hydraulically connected in series. In the case of a load, the second pressure chamber is preferably arranged downstream of the first pressure chamber and is particularly directly supported on the auxiliary valve piston. In particular, the pressure chambers have different volumes. The first pressure chamber preferably has a smaller volume than the second pressure chamber. Connecting the pressure chambers in series, especially pressure chambers with different volumes in series, ensures a velocity gradient of the movement of the auxiliary piston, where due to the series connection, the second pressure chamber causes a displacement of the auxiliary piston only when the first pressure chamber is already filled.

[0022] For example, the first pressure chamber is arranged such that the force generated by the hydraulic pressure in the first pressure chamber moves the auxiliary valve piston within a first axial stroke range, while the second pressure chamber is arranged such that the force generated by the hydraulic pressure in the second pressure chamber moves the auxiliary valve piston within a second axial stroke range. The first axial stroke range is a part, especially a section, of the second axial stroke range. The second axial stroke range is preferably the maximum axial offset, especially the entire axial movement range of the auxiliary piston. Setting different volumes in different pressure chambers advantageously causes different axial movements of the auxiliary piston, and thus different axial offsets of the piston in the high-speed and low-speed ranges of the movement of the working piston.

[0023] In another embodiment, the preloading system has a first orifice for allowing hydraulic fluid to enter the first pressure chamber and a second orifice for allowing hydraulic fluid to enter the second pressure chamber. The second orifice is preferably arranged between the first pressure chamber and the second pressure chamber. For example, the first and second pressure chambers are directly connected through the second orifice. The first and second orifices are preferably designed as fluid inlets, in particular as inlet openings, for allowing hydraulic fluid to enter the respective pressure chambers. The fluid inlet for introducing hydraulic fluid into the preloading system is preferably covered by a spring disc which forms a non-return valve. In particular, the first orifice is designed as an opening in the spring disc. The design of filling the pressure chambers through the respectively corresponding orifices provides the advantage of independent filling. For example, the respective pressure chambers can be filled at different filling rates. Optionally, the first orifice is designed as a flow opening in a flow channel, where in particular only one auxiliary piston is provided.

[0024] In another embodiment, the cross-sectional area of the first orifice is larger than the cross-sectional area of the second orifice. For example, the cross-sectional area of the first orifice is about 2 to 10 times, preferably 3 to 6 times, in particular 5 times that of the second orifice. As an alternative, the two orifices can have the same size. For example, the first orifice is designed as a main flow channel in the main piston or a cross-sectional area constriction in the main flow channel. For example, the main piston does not have a main valve device. For example, the orifices have different cross-sectional areas, which ensures different filling rates for the two pressure chambers. The larger first orifice ensures rapid filling of the first pressure chamber, resulting in a more rapid change in the volume of the first pressure chamber, and thus a faster movement speed of the auxiliary piston when filling the first pressure chamber, while slower when filling the second pressure chamber.

[0025] In another embodiment, the preloading system has a separating disc for fluidically isolating the first pressure chamber from the second pressure chamber. The separating disc can be, for example, a separating spring disc.

[0026] In another embodiment, the second orifice is designed as an opening in the separating disc, in particular in the separating spring disc, for fluidically connecting the first and second pressure chambers. Preferably, the first and second pressure chambers are only fluidically connected through the second orifice. This design enables a series connection of the two pressure chambers and preferentially allows the pressure chambers to be filled at different rates.

[0027] The second pressure chamber is preferably formed between the auxiliary valve piston and the separating disc, while the first pressure chamber is formed between the separating disc and the auxiliary valve body or the main piston. The separating disc and the auxiliary valve disc group are preferably arranged on opposite sides of the auxiliary valve piston.

[0028] For example, the first and / or second orifice designed as an opening can be circular or slot-shaped. In particular, the separating disc has a plurality of openings which are preferably arranged on the piston rod at the same radial distance and together form the second orifice.

[0029] In another embodiment, the separating disk is mounted so as to be axially movable relative to the auxiliary valve body and the piston rod. In another embodiment, the separating disk is supported on the auxiliary valve piston and preferably moves together with the auxiliary valve piston. The axial mobility of the separating disk causes the volume of the first pressure chamber to change during the movement of the separating disk, especially when moving together with the auxiliary valve piston, thereby enabling a simple coupling of the change in the volume of the first pressure chamber with the movement of the auxiliary piston.

[0030] In another embodiment, the preloading system has an axial stop to limit the axial movement of the separating disk. The stop is preferably formed in the auxiliary valve body, especially as the contact surface of the separating disk. In particular, this contact surface is at a certain distance from the bottom region. The side region of the auxiliary valve body preferably has an inner wall which is designed as an axial sliding surface for the auxiliary valve piston and along which the auxiliary valve piston can slide. Preferably, a groove is formed in the inner wall, which extends axially from the end facing the bottom region in the direction of the auxiliary valve piston and opens into the contact surface. The stop, especially the contact surface, preferably extends radially and preferably forms an axial stop for the spring disk. The stop is preferably designed and arranged to limit the axial movement of the separating disk, thereby limiting the increase in the volume of the first pressure chamber.

[0031] In another embodiment, the flow passage has a flow path which opens into the first auxiliary piston to allow hydraulic fluid to enter, while the flow passage has another flow path which opens into the second auxiliary piston to allow hydraulic fluid to enter. For example, the flow passage has exactly two or more flow paths for fluidly connecting the flow passage with the auxiliary pistons.

[0032] In another embodiment, the auxiliary valve disk group is fixed to the valve body. For example, the auxiliary valve disk group is mounted in a fixed position relative to the piston rod and cannot move relative to it. The auxiliary valve disk group can also be fixed to the auxiliary valve piston.

[0033] In another embodiment, the auxiliary valve piston has a groove which at least partially forms the second pressure chamber. This groove preferably increases the hydraulically effective area of the side of the auxiliary valve piston facing the second pressure chamber.

[0034] In another embodiment, the main piston has a main valve device, wherein the flow passage is arranged hydraulically in parallel with the main valve device. The main valve device preferably connects the working space on the piston rod side with the working space on the side away from the piston rod. The main valve device preferably includes a main valve body and at least two main flow passages formed in the main valve body, namely a first main flow passage and a second main flow passage. The main flow passages preferably extend from one end of the working piston, especially one end of the main valve body, to the opposite end and are arranged independently of each other, preferably arranged independently of each other in a fluid-isolated manner.

[0035] The main valve device preferably includes at least two spring disc valves, which are respectively installed at the ends of the main valve device, especially at the ends of the valve body. In particular, the spring disc valves are arranged to respectively determine the flow rate through the main flow passage. Each main flow passage preferably corresponds to only one spring disc valve. The main valve device preferably has a first spring disc valve, which interacts with the first main flow passage, so as to preferably determine the flow rate of the hydraulic fluid through the main flow passage according to the flow velocity.

[0036] Each spring disc valve preferably includes at least one spring disc group. The spring disc group is preferably preloaded onto and supported on the main valve seat formed in the main valve body. The spring disc group is preferably arranged on its respective main valve seat such that they lift from the main valve seat when there is only flow in one direction along the respective main flow passage, completely or partially exposing the flow cross-section of the main flow passage.

[0037] For example, a sealing element, especially a sealing ring, is circumferentially arranged around the main valve seat. Preferably, the sealing element is fluid-sealingly supported on the inner wall of the shock absorber cylinder.

[0038] In another embodiment, the working piston has two auxiliary pistons, and each auxiliary piston has an auxiliary valve device, wherein the auxiliary valve devices are fluid-connected through a flow passage. In this way, the above-mentioned frequency-sensitive damping is achieved in both the compression stage and the stretching stage.

[0039] In another embodiment, each auxiliary valve device has a fluid inlet for allowing hydraulic fluid to enter the auxiliary valve device, wherein each auxiliary piston has a fluid outlet for allowing hydraulic fluid to be discharged from the auxiliary piston, and the fluid inlet of the first auxiliary valve device is fluid-connected to the fluid outlet of the second auxiliary piston through a flow passage. For example, each fluid outlet interacts with an outlet spring disc group. The outlet spring disc group is preferably arranged to completely close the fluid outlet and preferably includes at least one spring disc, preferably completely covering the corresponding fluid outlet. As a preferred option, each fluid outlet only allows the flow from the inside of the respective auxiliary valve device to the outside into the corresponding working space. The outlet spring disc group is preferably designed as a one-way valve. Description of the Drawings

[0040] The following text further describes the present invention in more detail through multiple exemplary embodiments in combination with the drawings.

[0041] Figure 1 A longitudinal sectional schematic view of a shock absorber according to an exemplary embodiment is shown.

[0042] Figure 2 A longitudinal sectional schematic view showing local details of a shock absorber according to another exemplary embodiment is shown.

[0043] Figure 3Shows a longitudinal sectional schematic view of partial details of a shock absorber according to another exemplary embodiment.

[0044] Figure 4 Shows a longitudinal sectional schematic view of partial details of a shock absorber without a main piston valve according to another exemplary embodiment.

[0045] Figure 5 Shows a longitudinal sectional schematic view of partial details of a shock absorber with a main piston valve and only one auxiliary piston according to another exemplary embodiment.

[0046] Figure 1 Shows a shock absorber 10, wherein the shock absorber 10 is a single-tube shock absorber. Of course, the shock absorber can also be designed as a multi-tube shock absorber, such as a double-tube shock absorber. The shock absorber 10 has a shock absorber cylinder 12, which in the Figure 1 shown single-tube shock absorber, forms the outer tube and forms the outer surface of the shock absorber 10, particularly as its housing.

[0047] A working piston 18 connected to the piston rod 20 is arranged within the shock absorber cylinder 12 so that it can move within the shock absorber cylinder 12. The shock absorber cylinder 12 is preferably designed as a guiding device for the working piston 18. The working piston 18 has, for example, a valve device ( Figure 1 not shown in the figure). The working piston 18 divides the interior of the shock absorber cylinder 12 into a first working space 22 on the side close to the piston rod and a second working space 24 on the side away from the piston rod.

[0048] For example, the interior of the shock absorber cylinder 12 is fluid-sealed on the piston rod side by a sealing assembly. At the opposite end of the sealing assembly, i.e., the end away from the piston rod, the interior of the shock absorber cylinder 12 is fluid-sealed from an adjacent gas space by a separating piston. The gas space is arranged within the shock absorber cylinder 12, and the separating piston is preferably mounted axially movably within the shock absorber cylinder 12.

[0049] The shock absorber can also be designed as a multi-tube shock absorber. In the case of being designed as a multi-tube shock absorber, the outer tube surrounds the shock absorber cylinder 12 and is arranged coaxially therewith. A compensation space is formed between the outer tube and the inner tube, and this space is preferably at least partially filled with a hydraulic fluid. For example, the compensation space is partially filled with gas. At the opposite end of the sealing assembly, i.e., the end away from the piston rod, the interior of the shock absorber cylinder 12 of the multi-tube shock absorber is preferably fluid-sealed by a bottom assembly. As an example, a bottom valve is mounted on the bottom assembly, particularly at the end of the inner tube away from the piston rod. The second working space 24 is preferably fluid-connected to the compensation space through the bottom valve.

[0050] The working piston 18 includes a main piston 14 which forms a fluid-tight connection with the damper cylinder 12 at least partially. In addition, the working piston 18 includes two auxiliary pistons 26 and 28, namely a first auxiliary piston 26 and a second auxiliary piston 28. Of course, the working piston may also include only one auxiliary piston. By way of example only, in Figure 1 and Figure 2 a damper with two auxiliary pistons is shown. By way of example, the auxiliary pistons 26 and 28 are arranged spaced apart from the damper cylinder 12, thus allowing fluid to flow between the auxiliary pistons 26, 28 and the inner wall of the damper cylinder 12. In particular, the auxiliary pistons 26 and 28 are coaxially mounted on the piston rod 20 with respect to the main piston 14, preferably in a fixed position. By way of example, the first auxiliary piston 26 is located in the working space 22 on the piston rod side and is located in the tensile direction Z with respect to the main piston 26; by way of example, the second auxiliary piston 28 is located in the working space 24 away from the piston rod and is located in the compression direction D with respect to the main piston 26. The main piston 14 and the auxiliary pistons 26, 28 each preferably have their own valve means. By way of example, the main piston 14 has a main valve means 16, while the auxiliary pistons 26 and 28 respectively have auxiliary valve means 46 and 48.

[0051] Figure 2 A detail view of the working piston 18 with the main piston 14 and the auxiliary pistons 26, 28 is shown. The main piston 14 has a main valve means 16 which connects the working space 22 on the piston rod side and the working space 24 on the side away from the piston rod. The main valve means 16 includes a main valve body 30 and at least two main flow channels 32 and 34 formed in the main valve body 30, namely a first main flow channel 32 and a second main flow channel 34. The main flow channels 32 and 34 preferably each extend from one end of the working piston 18, especially one end of the main valve body 30, to the opposite end and are arranged independently of each other, preferably in a fluid-isolated manner.

[0052] The main valve means 16 includes at least two spring disc valves 36 and 38 which are respectively mounted at the ends of the main valve means 16, especially at the ends of the valve body 30. The spring disc valves 36 and 38 are arranged to respectively control the flow rate through the respective main flow channels 32 and 34. Each of the main flow channels 32 and 34 preferably corresponds to only one spring disc valve 36 and 38. The main valve means 16 preferably has a first spring disc valve 36 which interacts with the first main flow channel 32 and preferably determines the flow rate of the hydraulic fluid through the main flow channel 32 according to the flow velocity.

[0053] Each spring disc valve 36, 38 preferably includes at least one spring disc group. The spring disc group is composed of a plurality of spring discs and is preloaded onto and supported on the main valve seats 40, 42 formed in the main valve body 30. The spring disc group is preferably arranged on the respective main valve seats 40, 42 such that it lifts from the main valve seats 40, 42 only during unidirectional flow in the corresponding main flow channels 32, 34, partially or completely exposing the flow cross-section of the main flow channels. The spring disc valves 36, 38 are preferably designed as check valves, so that when the flow direction is reversed, the spring disc group does not lift from the respective main valve seats 40, 42. The corresponding spring disc valves 36, 38 are in the open position when the spring disc group lifts from the main valve seats 40, 42; when the spring disc group abuts against the respective main valve seats 40, 42, the corresponding spring disc valves 36, 38 are in the closed position.

[0054] When the piston rod 20 moves in the compression direction D, the flow direction through the first main flow channel 32 is the tensile direction Z, and at this time the first spring disc valve 36 is opened. Therefore, the first spring disc valve 36 is also called the compression stage valve. When the piston rod 20 moves in the tensile direction Z, the flow direction through the second main flow channel 34 is the compression direction D, and at this time the second spring disc valve 38 is opened. Therefore, the second spring disc valve 38 is also called the tensile stage valve. Here, the stiffness, number and size of the spring discs preferably determine the damping characteristics of the piston's movement in the tensile or compression direction.

[0055] For example, the sealing element 44 is arranged circumferentially along the main valve seat 30, and this sealing element is preferably fluid-sealingly supported on the inner wall of the shock absorber cylinder 12.

[0056] The auxiliary pistons 26 and 28 respectively have their own auxiliary valve devices 46 and 48, and the two are preferably designed basically the same. The auxiliary valve devices 46 and 48 are preferably arranged respectively within the respective auxiliary pistons 26 and 28. For example, the piston rod 20 is designed as a two-part structure, but a single structure can also be used. A flow channel 50 is preferably formed within the piston rod 20 for fluid-connecting the auxiliary pistons 26, 28, especially the auxiliary valve devices 46, 48. The working space 22 away from the piston rod and the working space 24 close to the piston rod are preferably interconnected through the flow channel 50 and the auxiliary pistons 26, 28, especially the auxiliary valve devices 46, 48. The flow channel 50 is preferably designed as an annular space and extends axially along the piston rod 20. For example, the flow channel 50 is formed within the piston rod 20 or between the piston rod 20 and the working piston 18 mounted thereon. The flow channel 50 preferably has a plurality of flow channels 66 and 68 for delivering hydraulic fluid into the respective auxiliary pistons 26, 28.

[0057] The flow passage 50 preferably extends from the first auxiliary piston 26, particularly from the first auxiliary valve device 46, to the second auxiliary piston 28, particularly to the second auxiliary valve device 48, along the flow direction of the hydraulic fluid. The flow passage 50 is preferably hydraulically parallel to the main piston 14, particularly to the main valve device 16.

[0058] Each of the auxiliary valve devices 46, 48 has a fluid inlet 52, 54 respectively for allowing hydraulic fluid to enter the corresponding auxiliary valve device 46, 48. Each of the auxiliary pistons 26, 28 also has a fluid outlet 58, 60 respectively for allowing hydraulic fluid to discharge from the corresponding auxiliary piston 26, 28, particularly from the corresponding auxiliary valve device 46, 48. Each fluid outlet 58, 60 preferably has an outlet spring disc 62, 64, so that the fluid outlet 58, 60 only allows unidirectional flow. The outlet spring discs 62, 64 preferably include at least one spring disc, which preferably completely covers the corresponding fluid outlet 58, 60. As a preference, each fluid outlet 58, 60 preferably only allows unidirectional flow, and the liquid flow can only flow from the inside of the respective auxiliary pistons 26, 28 to their respective working spaces 22, 24. Each fluid outlet is preferably designed as a one-way valve.

[0059] As an example, the flow passage 50 has at least two or exactly two flow paths 66, 68. For example, each of the auxiliary pistons 26, 28 is fluidly connected to the flow passage 50 through at least one or exactly one flow path 66, 68 respectively. For example, the fluid inlets 52, 54 of each of the auxiliary valve devices 46, 48 of the auxiliary pistons 26, 28 are fluidly connected to the flow passage 50 and the fluid outlets 58, 60 of the other auxiliary pistons 26, 28 in each case through the flow paths 66, 68. For example, the fluid inlet 52 of the first auxiliary valve device 46 of the first auxiliary piston 26 is fluidly connected to the fluid outlet 58 of the second auxiliary piston 28 through the flow passage 50. In particular, the fluid inlet 54 of the second auxiliary valve device 48 of the second auxiliary piston 28 is connected to the fluid outlet 60 of the first auxiliary piston 26 through the flow passage 50.

[0060] Figure 2The liquid flow when the piston rod 20 moves in the compression direction D is indicated by the dashed arrow. During the operation of the shock absorber 10, when the working piston 18 moves in the compression direction D, as long as the hydraulic pressure exceeds the opening pressure of the first spring disc valve 36, the hydraulic fluid flows through the main piston 14 towards the tension direction Z and opens the first spring disc valve 36. As long as the opening pressure of the auxiliary spring disc group 70 is exceeded, in parallel with the fluid flowing into the main piston 14, the hydraulic fluid enters the second auxiliary valve device 48 through the fluid inlet 54 of the second auxiliary valve device 48 and opens the second auxiliary valve device 48. The hydraulic fluid then flows into the flow channel 50 of the piston rod 20 through the flow path 68, exits from the flow channel 50 and then flows into the first auxiliary piston 26 through the flow path 66 and towards the fluid outlet 60 of the first auxiliary piston 26; if the opening pressure of the outlet spring disc 64 is exceeded, the hydraulic fluid leaves the first auxiliary piston 26 and enters the working space 22 near the piston rod. When the piston rod 20 moves in the tension direction Z, the first auxiliary valve device 46 and the main valve device 16 are opened in a corresponding manner.

[0061] Figure 3 Details of the second auxiliary valve device 48 are shown. The second auxiliary valve device 48 is preferably designed substantially the same as the first auxiliary valve device 46, so only one of the two auxiliary valve devices 46, 38 will be described as an example below. For example, the auxiliary valve devices 46, 48 have an auxiliary valve disc group 70 which includes at least one or more spring discs. The auxiliary valve disc group 70 is preferably arranged downstream of the fluid inlets 58, 60 of the auxiliary valve devices 46, 48 along the flow direction of the hydraulic fluid. In particular, the auxiliary valve disc group 70 can apply a preloading force. In the closed position, the auxiliary valve disc group 70 is preferably supported on the auxiliary valve seat 84, especially preloaded onto the auxiliary valve seat with a preloading force. When the auxiliary valve devices 46, 48 are in the open position, the auxiliary valve disc group 70 is lifted from the auxiliary valve seat 84.

[0062] The auxiliary valve devices 46, 48 have an auxiliary valve body 74, preferably installed at a fixed position of the piston rod 20. For example, the auxiliary valve body 74 forms the housing of the auxiliary valve devices 46, 48, especially the housing of the auxiliary pistons 26, 28. The auxiliary valve body 74 is especially in the form of a hollow cylinder, having a top region facing the main piston 14, a cylindrical side region and a bottom region away from the main piston 14. For example, an axially movable auxiliary valve piston 76 is arranged within the auxiliary valve body 74. The auxiliary valve piston 76 is preferably at least partially supported on the auxiliary valve body 74 and is installed in an axially movable manner relative to the auxiliary valve body and the piston rod 20.

[0063] The auxiliary valve piston 76 preferably includes an auxiliary valve seat 84 and is supported on the auxiliary valve disk assembly 70 through this auxiliary valve seat. For example, the diameter of the auxiliary valve piston 76 gradually decreases in the direction towards the auxiliary valve seat. The axial movement of the auxiliary valve piston 76 causes a change in the preloading of the auxiliary valve disk assembly 70 on the valve seat. For example, the auxiliary valve disk assembly 70 can be fixed to the auxiliary valve body 74, especially clamped on the auxiliary valve body 74. For example, the auxiliary valve disk assembly 70 includes three spring disks that support each other, among which the lower spring disk near the valve seat has the largest diameter, and as an example, the other spring disks have smaller diameters.

[0064] The auxiliary valve devices 46, 48 preferably include a preloading system 56 for applying a preloading force to the auxiliary valve disk assembly 70, especially an axial force to the auxiliary valve piston 76. The preloading system 56 is preferably part of the auxiliary pistons 26, 28 and the auxiliary valve devices 46, 48. The preloading system 56 preferably includes a first pressure chamber 72 and a second pressure chamber 73 that are hydraulically connected in series. The pressure chambers 72 and 73 are arranged to interact with the auxiliary valve piston 76, so that when the pressure in the pressure chambers 72, 73 changes, the auxiliary valve piston 76 moves axially.

[0065] The pressure chambers 72 and 73 are preferably arranged on the side of the auxiliary valve piston 76 opposite to the auxiliary spring disk assembly 70. For example, the preloading system 56 also includes two orifices 80 and 82, which are respectively used as inlets to allow hydraulic fluid to enter the respective pressure chambers 72, 73. The first orifice 80 is preferably designed and arranged as an inlet for hydraulic fluid to enter the first pressure chamber 72. For example, the preloading system 56 has a fluid inlet 94, which is designed as a hole in the auxiliary valve body 74, especially arranged on the side of the auxiliary valve body 74 away from the main piston 14. The fluid inlet 94 is preferably covered by a spring disk 96, which forms a check valve, especially only allowing fluid to flow from the auxiliary pistons 26, 28, especially the preloading system 56, to the corresponding working spaces 22, 24. For example, the first orifice 80 is designed as an opening in the spring disk.

[0066] For example, the first and second pressure chambers 72, 73 are separated from each other by a separating spring disk 78. Thus, the first pressure chamber 72 and the second pressure chamber 73 are respectively supported on the spring disk 78. The second orifice 82 is preferably designed as an opening in the separating spring disk 78 and is an inlet for hydraulic fluid from the first pressure chamber 72 to the second pressure chamber 73. For example, the separating spring disk 78 is supported on the auxiliary valve piston 76. In particular, the separating spring disk 78 is mounted to be axially movable relative to the piston rod 20 and the auxiliary valve body 74. The separating spring disk 78 preferably moves together with the auxiliary valve piston 76. The first orifice 80 preferably has a larger cross-sectional area than the second orifice 82. For example, the first pressure chamber 72 is formed between the separating spring disk 78 and the auxiliary valve body 74, while the second pressure chamber 73 is preferably formed between the separating spring disk 78 and the auxiliary valve piston 76.

[0067] For example, the preloading system 56 also has an axial stop 90 for restricting the axial movement of the separating spring disk 78. For example, the axial stop 90 is formed within the auxiliary valve body 74. In particular, the stop 90 is designed as a radial contact surface for contacting and in particular supporting the separating spring disk 78. The stop 90 preferably restricts the volume of the first pressure chamber 72, in particular its volume increase.

[0068] The first and second pressure chambers 72, 73 of the preloading system 56 are preferably only fluidly connected to the working spaces 22, 24 in which the corresponding auxiliary pistons 26, 28 are arranged. The pressure chambers 72, 73 are not fluidly connected to the two working spaces 22, 24 simultaneously. For example, the auxiliary valve piston 76 has a groove 92 which at least partially forms the second pressure chamber 73. The separating spring disk 78 and the auxiliary valve disk group 70 are preferably arranged on opposite sides of the auxiliary valve piston 76.

[0069] During the operation of the shock absorber 10, when the piston rod 20 is excited at a low speed in the compression direction D, for example, the hydraulic fluid first enters and fills the first pressure chamber 72 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 the latter is also filled with the hydraulic fluid. Since the cross-sectional area of the second orifice 82 is smaller than that of the first orifice 80, the filling speed of the hydraulic fluid in the second pressure chamber 73 is slower than that in the first pressure chamber 72. The gradually increasing hydraulic pressure in the first pressure chamber 72 causes the separating spring plate 78 and the auxiliary valve piston 76 supported thereon to move axially, thereby increasing the volume of the first pressure chamber 72. During the process of increasing the volume of the first pressure chamber 72, the separating spring plate 78 moves towards the stop 90, and at the same time, the separating spring plate 78 and the auxiliary valve piston 76 move at a first speed. Once the separating spring plate 78 reaches the stop 90 and is supported thereon, the volume of the first pressure chamber 72 will no longer increase. Due to the smaller opening size of the second orifice 82, the pressure in the second pressure chamber 73 rises slowly, ensuring that the volume of the second pressure chamber 73 increases slowly, resulting in the axial movement of the auxiliary valve piston 76. Especially after the separating spring plate 78 abuts against the stop 90, the auxiliary valve piston 76 moves at a second speed, which is lower than the first speed. This design ensures that at a lower piston speed, a frequency-sensitive setting for preloading the auxiliary valve disc assembly 70 is achieved. High-frequency excitation causes the auxiliary valve piston 76 to move at the first speed, while low-frequency excitation causes the auxiliary valve piston 76 to first move at the first speed and then at the second speed, providing higher damping at low frequencies, especially more significant preloading effect on the auxiliary valve disc assembly 70.

[0070] During the operation of the shock absorber, when excited in the compression direction D, as long as the hydraulic pressure exceeds the opening pressure of the preloaded auxiliary valve disc assembly 70, the hydraulic fluid flows through the fluid inlets 52, 54 into the auxiliary valve devices 46, 48 and opens them. The hydraulic fluid preferably enters the flow passage 50 through the auxiliary valve devices 46, 48, flows towards the fluid outlets 58, 60 of the opposite auxiliary pistons 26, 28, and enters the opposite working spaces 22, 24, especially the low-pressure spaces.

[0071] Figure 4 Another exemplary embodiment is shown, which is basically the same as Figures 1 to 3 similar, except that Figure 4 the main piston 14 in

[0072] In Figure 4In an exemplary embodiment, the auxiliary valve piston 76 is designed, for example, as a two-part structure, wherein the region of the auxiliary valve piston 76 that abuts against the auxiliary valve disc group 70 is designed as an annular disc. The auxiliary valve piston can also be composed of more than two parts, which are installed in a manner that moves together relative to the auxiliary valve housing 74. For example, an auxiliary valve seat 88 is formed in the auxiliary valve housing 74 such that, in the closed position, the auxiliary valve disc group 70 is supported on the valve seat 88 of the auxiliary valve housing 74. The auxiliary valve disc group 70 is installed, for example, to be axially movable and thus preferably movable together with the auxiliary valve piston.

[0073] As an example, the pressure chambers 72, 73 are arranged on the side of the respective auxiliary pistons 26, 28 facing the main piston 14. As an example, the fluid inlets 54 for allowing the hydraulic fluid of the auxiliary valve devices 46, 48 to flow in are arranged on the side of the auxiliary pistons 26, 28 away from the main piston 14. In particular, the fluid inlets 54 are covered by spring discs designed as one-way valves. The one-way valves are arranged to prevent the hydraulic fluid from flowing from the auxiliary pistons 26, 28, especially the auxiliary valve devices 46, 48, into the corresponding working spaces 22.

[0074] As an example, the main flow channels 32 and 34 form a first orifice 80, which is designed to allow the hydraulic fluid to enter the inlet of the first pressure chamber 72. The main flow channel 34 preferably has a cross-sectional contraction that forms the first orifice 80.

[0075] During Figure 4 the operation of the shock absorber 10 in Figure 3 , especially when the piston rod moves in the compression direction D, the hydraulic fluid enters the second auxiliary piston 48 through the fluid inlet 54, and then enters the first auxiliary valve device 46 in the first auxiliary piston 26 through the flow channel 50. When the opening pressure of the auxiliary valve disc group 70 of the first auxiliary valve device 46 is exceeded, the valve device opens and the hydraulic fluid flows to the low-pressure space. At the same time, the hydraulic fluid enters the first pressure chamber 72 through the second main flow channel 34, and then enters the second pressure chamber 73, in this way setting the preloading of the auxiliary valve disc group 70, as described in

[0076] Figure 5 shows another exemplary embodiment of the shock absorber 10, the structure of which is basically the same as that in Figure 2 and Figure 3 in Figure 2 and Figure 3 . Different from the exemplary embodiments of Figure 5 , the shock absorber 10 in Figure 4is the same as the auxiliary piston therein, except that the first orifice 80 is designed as a flow opening in the flow passage 50. In addition, Figure 5 the auxiliary piston 28 of the exemplary embodiment in does not have a fluid inlet 54 that allows fluid to enter the auxiliary piston 28 from the working space 24 away from the piston rod. In Figure 5 in the shock absorber 10 in, the flow passage 68 in the flow passage 50 is designed to allow hydraulic fluid to enter the fluid inlet of the auxiliary piston 28. The auxiliary piston 28 is preferably designed such that only hydraulic fluid flows from the working space 22 without the auxiliary piston into the auxiliary piston. For example, the auxiliary valve disc group 70 is designed as a check valve and arranged such that fluid can only flow through the fluid outlet 58 in a single direction, so that the hydraulic fluid can only flow out of the auxiliary piston 28 through the fluid outlet 58. When the piston rod moves in the tensile direction Z, Figure 5 in the exemplary embodiment of, the hydraulic fluid enters the flow passage 50 through the flow passage 66 in the piston rod 20, and then enters the auxiliary piston 28 through the flow path 68. In the auxiliary piston 28, the hydraulic fluid passes through the auxiliary piston valve device 48 and opens the auxiliary valve disc group 70. At the same time, the hydraulic fluid enters the first pressure chamber 72 through the first orifice 80, and then enters the second pressure chamber 73 through the second orifice 82. The auxiliary valve piston 76 moves towards the auxiliary valve disc group 70 and preloads it.

[0077] List of reference numerals

[0078] 10 Shock absorber

[0079] 12 Shock tube

[0080] 14 Main piston

[0081] 16 Main valve device

[0082] 18 Working piston

[0083] 20 Piston rod

[0084] 22 Working space on the piston rod side

[0085] 24 Working space on the side away from the piston rod

[0086] 26 First auxiliary piston

[0087] 28 Second auxiliary piston

[0088] 30 Main valve body

[0089] 32 First main flow passage

[0090] 34 Second main flow passage

[0091] 36 First spring disc valve

[0092] 38 Second spring disc valve

[0093] 40 First main valve seat

[0094] 42 Second main valve seat

[0095] 44 Sealing element

[0096] 46 First auxiliary valve device

[0097] 48 Second auxiliary valve device

[0098] 50 Flow passage

[0099] 52, 54 Fluid inlet

[0100] 56 Preloading system

[0101] 58, 60 Fluid outlet

[0102] 62, 64 Outlet spring plate

[0103] 66, 68 Flow path

[0104] 70 Auxiliary valve disc group

[0105] 72 First pressure chamber

[0106] 73 Second pressure chamber

[0107] 74 Auxiliary valve body

[0108] 76 Auxiliary valve piston

[0109] 78 Separator spring plate

[0110] 80 First orifice

[0111] 82 Second orifice

[0112] 84 Auxiliary valve seat

[0113] 86 Spacer gasket

[0114] 88 Valve seat

[0115] 90 Stop

[0116] 92 Groove

[0117] 94 Fluid inlet

[0118] 96 Spring plate

Claims

1. A shock absorber (10) for a motor vehicle, comprising: The shock absorber cylinder (12) and A working piston (18) is arranged in the damper cylinder (12) in an axially movable manner and divides the interior of the damper cylinder (12) into a working space (22) close to the piston rod side and a working space (24) away from the piston rod side. in, The working piston (18) comprises a main piston (14) and at least one auxiliary piston (26, 28). The auxiliary piston (26, 28) has an auxiliary valve device (46, 48), and the auxiliary valve device is fluidically connected to the working space (22, 24) of the damping cylinder (12) through a flow channel (50), wherein the auxiliary valve device (46, 48) includes: an auxiliary valve body (74) and an auxiliary valve piston (76) that is axially movable relative to the auxiliary valve body (74), and an auxiliary valve disc assembly (70) which interacts with the auxiliary valve piston (76), The characteristic is that The auxiliary valve device (46, 48) has a preload system (56) for applying a preload force to the auxiliary valve disc group (70), wherein the preload system (56) includes a first pressure chamber (72) with a variable volume and a second pressure chamber (73) with a variable volume.

2. The shock absorber (10) according to claim 1, wherein the first and second pressure chambers (72, 73) are hydraulically connected in series.

3. A shock absorber (10) according to any of the preceding claims, wherein the preload system (56) has a first orifice (80) allowing hydraulic fluid to enter the first pressure chamber (72), and a second orifice (82) allowing hydraulic fluid to enter the second pressure chamber (73).

4. The vibration absorber (10) of claim 3, wherein the first aperture (80) has a larger cross-sectional area than the second aperture (82).

5. The shock absorber (10) according to any of the preceding claims, wherein the preload system (56) has a separation disk (78) which separates the first pressure chamber (72) and the second pressure chamber (73) from one another.

6. The shock absorber (10) according to claim 5, wherein the second opening (82) is designed as an opening in a separating disk (78) for fluidically connecting the first and second pressure chambers (72, 73).

7. The shock absorber (10) according to claim 5 or 6, wherein the separation disk (78) is mounted in an axially movable manner relative to the auxiliary valve body (74).

8. The vibration absorber (10) of claim 7, wherein the preload system (56) has an axial stop (90) for limiting axial movement of the separator disk (78).

9. Shock absorber (10) according to any one of claims 5 to 8, wherein the separating disk (78) bears against the auxiliary valve piston (76).

10. A shock absorber (10) according to any of the preceding claims, wherein the circulation channel (50) has a circulation path (66) which opens into the first auxiliary piston (26) to allow the hydraulic fluid to enter; and the circulation channel (50) has another circulation path (68) which opens into the second auxiliary piston (28) to allow the hydraulic fluid to enter.

11. The shock absorber (10) according to any of the preceding claims, wherein the auxiliary valve disc assembly (70) is fixed to the valve body (74).

12. Shock absorber (10) according to any of the preceding claims, wherein the auxiliary valve piston (76) has a recess (92) which at least partially forms the second pressure chamber (73).

13. The shock absorber (10) according to any of the preceding claims, wherein the primary piston (14) has a primary valve device (16), and the flow channel (50) is arranged hydraulically in parallel with the primary valve device (16).

14. The shock absorber (10) according to claim 1, wherein the working piston (18) has two auxiliary pistons (26, 28), each auxiliary piston having an auxiliary valve device (46, 48), and the auxiliary valve devices (46, 48) are fluidically connected to each other via the flow channel (50).

15. The shock absorber (10) of claim 14, wherein each auxiliary valve device (46, 48) has a fluid inlet (52, 54) for allowing hydraulic fluid to enter the auxiliary valve device (46, 48), wherein each auxiliary piston (26, 28) has a fluid outlet (58, 60) for allowing hydraulic fluid to flow out of the auxiliary piston (26, 28), and the fluid inlet (52, 54) of the first auxiliary valve device (46) is fluidly connected to the fluid outlet (60) of the second auxiliary piston (28) through the flow channel (50).

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