Frequency-dependent damping valve arrangement

Abstract

Frequency-dependent damping valve arrangement (1) of a vibration damper, for a motor vehicle, comprising - a damping piston (4) arranged within at least one cylinder (2) at least partially filled with a damping fluid and axially fixed to a support (3) with a check valve (5), - a control arrangement (10) attached to the carrier (3), coaxial to the damping piston (4), comprising a control pot (11), an axially displaceable control piston (16) arranged in the control pot (11), and - at least one spring arrangement (20) arranged between the control piston (16) and the check valve (5) with at least one first spring element (21), wherein this spring element is supported axially on one side directly on the control piston (16) and on the other side at least indirectly on the check valve (5), deflects under load and introduces a spring force into the control piston (16) and at least indirectly into the check valve (5), wherein the control piston (16) has a height difference (16c) between its radially outer edge (16a) and its radially inner edge (16b) facing the radial center of the control piston (16), which defines a maximum deflection height of the first spring element (21),wherein the formal design of the surface (16d) of the control piston (16) facing the first spring element (21) between the radially outer edge (16a) and the radially inner edge (16b) of the control piston (16) is adapted to the formal design of the first spring element (21) in its loaded state, characterized in that the height difference (16c) is defined by the fact that the radially outer edge (16a) of the control piston (16) is raised above the remaining surface (16d) of the control piston (16) facing the first spring element (21), wherein the raised radially outer edge (16a) has an inner edge (16e) whose formal design is adapted to the formal design of the first spring element (21), which deflects the spring element (21) after its deformation up to the maximum permissible deflection height defined by the height difference (16c) of the control piston (16). assumeswherein the spring element (21) in the loaded state, after its deformation up to the maximum permissible deflection height defined by the height difference (16c) of the control piston (16), bears against the inner edge (16e) and the surface (16d) in order to define the deflection shape of the first spring element (21) and to influence the spring rate of the spring arrangement (20) in the loaded state in a defined manner.

Description

[0001] The invention relates to a damping valve arrangement of a vibration damper for a motor vehicle with a frequency-dependent damping force characteristic, according to patent claim 1.

[0002] The task of a vibration damper in a motor vehicle is to dampen the vibrations caused by uneven road surfaces. A compromise must always be found between driving safety and ride comfort. A vibration damper with a hard-tuned damping valve arrangement, thus offering a high damping force characteristic, is optimal for high driving safety. If high comfort requirements are to be met, the damping valve arrangement should be tuned as softly as possible. This compromise is very difficult to achieve with a vibration damper with a conventional damping valve arrangement that is not electronically adjustable using an actuator.

[0003] The document DE 10 2015 205 556 A1 discloses a piston assembly for a shock absorber, comprising a bypass passage formed along a vertical longitudinal direction of a piston rod in a small diameter portion stepped in a lower portion of the piston rod reciprocating within a cylinder; a main piston connected to the small diameter portion; an orifice assembly coupled to the small diameter portion and located below the main piston to form an orifice passage communicating with the bypass passage; a housing coupled to the small diameter portion and located below the orifice assembly, the housing having an open upper side and defining a pressure chamber;and a slide valve coupled to the orifice assembly and housed in the pressure chamber for generating a damping force by selectively opening and closing the orifice passage while reciprocating through a high-frequency section and a low-frequency section.;

[0004] The document DE 10 2015 211 891 A1 discloses a damping valve device for a vibration damper, comprising a damping piston with a check valve and a control arrangement with a control pot and a control piston axially movable therein, wherein at least one spring arrangement is arranged between the control piston and the damping piston, which spring arrangement axially loads the check valve with a defined spring force.

[0005] The publication DE 10 2016 210 950 A1 discloses a frequency-dependent base valve assembly of a vibration damper, comprising a damping valve axially fixed to a support and a control assembly mounted on the support. The control assembly has a control pot, an axially displaceable control piston arranged in the control pot, which axially delimits a control chamber enclosed in the control pot, and at least one spring assembly arranged between the control piston and the valve disc of the damping valve.

[0006] The document DE 10 2014 205 302 A1 discloses a damping force generating mechanism with a spring element having radially extending spring sections with high spring constants and circumferentially extending spring sections with low spring constants. The radially extending spring sections and the circumferentially extending spring sections are integrally designed such that the respective urging forces thereof act dynamically linearly. Furthermore, an annular step section, which limits deflections of the respective circumferentially extending spring sections, is arranged on a cylindrical wall section of a control body facing the opposite end side.As a result, within a range of damping force control, only the respective radially extending spring sections of the spring element are elastically deformed, whereby the durability of the spring element is improved and only urging forces of the respective radially extending spring sections of the spring element act on the control valve element.

[0007] The document US 2011 / 0 024 247 A1 discloses a damping force generating mechanism for a hydraulic shock absorber, in which a first fluid chamber and a second fluid chamber are defined by a valve disc, comprising an opening formed in the valve disc for causing fluid to flow from the first fluid chamber to the second fluid chamber; a damping valve closing the opening on the second fluid chamber side; a passage connecting the first fluid chamber to the opening; a throttle valve reducing a flow cross-sectional area of ​​the passage depending on a pressure of the first fluid chamber; a pressure chamber applying a pressure to the throttle valve opposite to the pressure of the first fluid chamber; and a disc spring biasing the throttle valve in a direction opposite to the pressure of the first fluid chamber.

[0008] US 2005 / 0 045 440 A1 discloses a shock absorber having a cylinder portion and a piston portion movable therein. The piston portion is sealed relative to the cylinder portion to define chambers on either side thereof, with a connecting channel provided between the chambers to interconnect the chambers. The connecting channel includes a valve arrangement for influencing the fluid flow through said connecting channel. Furthermore, a valve seat, a member movable relative thereto under fluid pressure, and a closing plate are provided to seal against the valve seat.

[0009] DE 10 2014 210 704 A1 discloses a generic damping valve arrangement with a frequency-dependent damping force characteristic. This arrangement comprises a damping valve arranged within a cylinder filled with a damping medium, said damping valve having at least one flow channel covered by a plurality of valve discs. Furthermore, the damping valve arrangement comprises a control arrangement mounted coaxially with the damping valve, comprising a control chamber with an axially displaceable control piston arranged in the control chamber. The control piston axially defines a control chamber enclosed in the control chamber, which is connected to the damping valve arrangement via an inlet connection. A spring element is arranged between the control piston and the damping valve, which axially introduces a spring force into the control piston on the one hand and into the damping valve on the other.If the control chamber is filled with damping medium, the control piston moves towards the damping valve and increases the contact pressure of the valve discs of the damping valve via the spring element, which increases the damping force.

[0010] The increase in the contact pressure of the valve disc of the check valve and thus also the damping force depends, among other things, on the pressure of the damping medium within the control chamber and on the spring rate of the spring element.

[0011] The object of the present invention is therefore to provide an alternative frequency-selective damping valve arrangement which offers the possibility of adjusting the increase in the contact pressure of the valve disc of the check valve and thus also the increase in the damping force in a defined manner.

[0012] This object is achieved by a damping valve arrangement with features according to claim 1. Further advantageous embodiments are specified in the figures and in the dependent claims.

[0013] According to the invention, the control piston has a height difference between its radially outer edge and its radially inner edge facing the radial center of the control piston, which defines a maximum deflection height and the deflection shape of the first spring element.

[0014] By determining the height difference between the radially outer edge and the radially inner edge of the control piston, the spring rate of the spring arrangement can be influenced in a defined manner and thus the increase in the contact pressure of the valve disc of the check valve and thus also the increase in the damping force can be defined.

[0015] According to the invention, the height difference is determined by the radially outer edge of the control piston being raised relative to the remaining surface of the control piston facing the first spring element. However, it can also be provided that the radially inner edge of the control piston is raised relative to the remaining surface of the control piston facing the first spring element.

[0016] Both versions are easy and inexpensive to manufacture.

[0017] The damping valve arrangement can advantageously comprise at least one additional spacer component which is arranged between the control piston and the first spring element, which simplifies a fine adjustment of the height difference.

[0018] According to the invention, the formal design of the surface of the control piston facing the first spring element between the radially outer edge and the radially inner edge of the control piston is adapted to the formal design of the first spring element in its loaded state, which promotes a very precise fine adjustment of the deflection height, as well as the deflection shape, of the first spring element.

[0019] According to the invention, the raised radially outer edge has an inner edge whose formal configuration is adapted to the formal configuration of the first spring element, which the spring element assumes after its deformation up to the maximum permissible deflection height defined by the height difference of the control piston.

[0020] Furthermore, the piston can advantageously be made of a plastic material and / or the radially outer edge of the control piston can be divided into several segments, which can, for example, have different axial heights or different surface finishes to reduce the weight of the control piston and / or to define the contact geometry of the first spring element on the piston. Contact geometry here refers to the surface geometry of the control piston against which the first spring element rests when under load.

[0021] The invention will now be explained in more detail with reference to the accompanying figures.

[0022] They show: Fig. 1: Sectional view of an exemplary embodiment of a frequency-dependent damping valve arrangement according to the invention in a cylinder of a vibration damper; Fig. 2: Sectional view of an exemplary embodiment of a control piston according to the invention; Fig. 3: partial sectional view of a control piston according to Fig. 2; Fig. 4: Partial sectional view of the control piston according to Fig. 3 with the first spring element of the spring arrangement in the loaded state; Fig. 5: Top view of the control piston according to Fig. 1 to 4.

[0023] The Fig. 1 shows a section of a vibration damper for a motor vehicle with a frequency-dependent damping valve arrangement 1 according to the invention in a sectional view.

[0024] This comprises a cylinder 2 at least partially filled with a damping fluid.

[0025] The damping valve assembly 1 is arranged axially displaceably within the cylinder 2 and is attached to a support 3. The damping valve assembly 1 comprises a damping piston 4 with at least one check valve 5, which has at least one first flow channel 6 for the damping fluid formed therein, which is covered by at least one valve disc 7.

[0026] The damping piston 4 separates a first working chamber 8 from a second working chamber 9 within the cylinder 2, so that the ratio of the damping medium pressure in the two working chambers 8, 9 varies depending on the direction of the axial movements of the damping piston 4 in the cylinder 2.

[0027] In addition, the damping valve arrangement 1 has a control arrangement 10 which contains a control pot 11 with a cylindrical pot wall 12 and a disc-shaped pot base 13 as well as with an axially displaceable control piston 16 arranged in the control pot 11, which axially delimits a control chamber 14 enclosed in the control pot 11.

[0028] A spring arrangement 20 is mounted between the damping piston 4 and the control arrangement 1, which applies a defined spring force to the valve disc 7 axially in the direction of the first flow channel 6 and to the control piston 16 in the direction of the pot bottom 13.

[0029] All components of the damping valve assembly 1 are arranged coaxially to each other on the carrier 3. As shown in the Fig. 1, the damping valve arrangement 1 is designed such that the carrier 3 extends centrally through the damping piston 4 and a guide sleeve 29, which in turn also extends centrally through the spring arrangement 20 and the control piston 16. The guide sleeve 29 comprises a first guide section 29a and an axially adjacent second guide section 29b, wherein the control piston 16 can slide axially along the first guide section 29a and the spring arrangement 20 can slide axially along the second guide section 29b, wherein the direction of the axial movements of the control piston 16 depends on the damping medium pressure in the control chamber 14.

[0030] The carrier 3 is shown here as a so-called piston rod journal, i.e. an end section of the piston rod with a reduced diameter. Fig. 1, it is provided that the damping valve arrangement 1 comprises at least one second flow channel 15 formed on and / or in the carrier 3 and the guide sleeve 29, which second flow channel connects the first and / or the second working chamber 8, 9 with the control chamber 14.

[0031] The control pot 11 of the control arrangement 1 is connected to the support 3 in the area of ​​the pot bottom 13 by means of a connecting means 30. The connecting means 30 is in the Fig. 1 and Fig. 2 as a threaded nut. Of course, the connecting means 30 can also have another suitable design. In general, the connection between the support 3 and the control pot 11 can be implemented as a material fit, a form fit, and / or a force fit.

[0032] The control piston 16 arranged within the control pot 11 is designed to be axially displaceable, so that when the damping fluid pressure in the control chamber 14 of the control arrangement 1 persists for a longer period, it can move in the direction of the valve disc 7 of the check valve 5 and tension the spring arrangement 20, whereby the spring force applied to the valve disc 7 by the spring arrangement 20 and thus the damping force of the check valve 5 is increased.

[0033] As in the Fig. As shown in Figure 1, the control piston 16 has a sealing arrangement 17, which seals the control piston 16 against the pot wall 12. This comprises a circumferential groove 19 formed on the control piston 16 with a sealing ring 18 arranged therein.

[0034] The second flow channel 15 comprises an inlet throttle 31, which defines the inflow of the damping medium from the first working chamber 8 into the control chamber 14.

[0035] Furthermore, an outlet throttle 32 is formed on the control piston 16, which influences the outflow of the damping medium from the control chamber 14, whereby this can also be formed on the carrier 3.

[0036] To define the soft and hard damping force characteristic curves, a first stop 33 and a second stop 34 are provided on the control arrangement 1. The first stop 33 is in the Fig. 1, the second stop 34 is designed as a stop ring, with the second stop 34 being designed as an at least partially raised portion of the pot base 13. Of course, the second stop 34 can also be designed as a stop ring or as an additional stop element, which can be arranged within the control chamber 14.

[0037] The spring arrangement 20 can be designed in different ways. In the Fig. 1, the spring arrangement 20 comprises a plurality of spring elements 21, 22, 23 which are separated from one another by a sliding element 26. The spring elements 21, 22, 23 and the sliding element 26 engage around the guide sleeve 29 and are arranged coaxially to the remaining components of the damping valve arrangement 1. The first spring element 21 is supported axially on the one hand on the control piston 16 and on the other hand on the sliding element 26. At least one of the further spring elements is supported at least indirectly on the one hand on the sliding element 26 and on the other hand via a spacer ring 24 on the valve disc 7.

[0038] In the case of a high-frequency excitation of the vibration damper, the damping fluid pressure in the control chamber 14 lasts only for a short time, whereas in the case of a low-frequency excitation of the vibration damper, the damping fluid pressure in the control chamber 14 lasts significantly longer.

[0039] The control arrangement 10 of the damping valve arrangement 1 is designed such that when the damping fluid pressure in the control chamber 14 of the control arrangement 10 persists for a longer period, the control piston 16 moves in the direction of the valve disc 7 of the check valve 5, tensions the spring arrangement 20, and thereby increases the spring force applied to the valve disc 7 by the spring arrangement 20 and thus the damping force of the check valve 5.

[0040] As already explained above, the damping valve arrangement 1 according to the invention comprises a spring arrangement 20 arranged between the control piston 16 and the check valve 5, which applies a defined spring force to the valve disc 7 axially in the direction of the damping piston 4 and to the control piston 16 in the direction of the pot bottom 13. This spring arrangement 20 has at least a first spring element 21, with an inner edge 21a facing the carrier 3 and an outer edge 21b facing away from the carrier 3. The spring element 21 is supported with at least one of the two edges 21a, 21b axially directly on the control piston 16 and with the other of the two edges 21a, 21b at least indirectly on the check valve 5. If the damping medium pressure in the control chamber 14 increases, the control piston 16 moves axially in the direction of the check valve 5 and tensions the spring arrangement 20.In this load state, at least the first spring element 21 bends and introduces a spring force into the control piston 16 and at least indirectly into the check valve 5.

[0041] As shown in all figures, the control piston 16 is designed such that it has a height difference 16c between its radially outer edge 16a and its radially inner edge 16b facing the radial center of the control piston 16. This height difference 16c defines a maximum deflection height of the first spring element 21 and enables an increase in the contact pressure of the valve disc 7 against the check valve 5 and thus also an increase in the damping force to be adjusted in a defined manner.

[0042] The height difference 16c can be determined, for example, by the radially outer edge 16a of the control piston 16 being raised relative to the remaining surface 16d of the control piston 16 facing the first spring element 21, as shown in the Fig. 2, Fig. 3 and Fig. 4. Alternatively, however, it can also be provided that the radially inner edge 16b of the control piston is raised relative to the remaining surface 16d of the control piston 16 facing the first spring element 21. This embodiment variant is not shown in the figures, but also falls within the scope of the present invention.

[0043] According to the Fig. 2, the radially outer edge 16a of the control piston 16 can be divided into several segments 27.

[0044] In addition, the formal design of the surface 16d of the control piston 16 facing the first spring element between the radially outer edge 16a and the radially inner edge 16b of the control piston 16 can be adapted to the formal design of the first spring element 21.

[0045] An example of this is shown by the overview of Fig. 3 and Fig. 4 is particularly evident. As in the Fig. 3 and Fig. 4, the raised radially outer edge 16a may have an inner edge 16e, the formal configuration of which is adapted to the formal configuration of the first spring element 21, which the spring element 16 assumes after its deformation up to the maximum permissible deflection height defined by the height difference 16c of the control piston 16.

[0046] As already explained above, the damping valve arrangement 1 can be provided with at least one additional spacer component 28, which is arranged between the control piston 16 and the first spring element 21 and serves for fine adjustment of the height difference 16c. Although this embodiment is not shown in the figures, it is also feasible within the meaning of the invention. Reference symbol 1 damping valve arrangement 2 cylinders 3 carriers 4 damping pistons 5 Check valve 6 first flow channel 7 Valve disc 8 first workroom 9 second workroom 10 Tax order 11 tax pot 12 Pot wall 13 Pot bottom 14 Control room 15 second flow channel 16 control pistons 16a radial outer edge of the control piston 16b radial inner edge of the control piston 16c elevation difference 16d surface 16th edge 17 Sealing arrangement 18 Sealing ring 19 grooves 20 Spring arrangement 21 first spring element 21a Inner edge of the first spring element 21b Outer edge of the first spring element 22 second spring element 23 third spring element 24 spacer ring 26 Sliding element 27 segments 28 Spacer component 29 Guide sleeve 29a first guide section 29b second guide section 30 lanyards 31 Inlet throttle 32 Outlet throttle 33 first attack 34 second attack A Longitudinal axis

Claims

[1] Frequency-dependent damping valve arrangement (1) of a vibration damper for a motor vehicle, comprising - a damping piston (4) arranged within at least one cylinder (2) at least partially filled with a damping fluid and axially fixed to a support (3) with a check valve (5), - a control arrangement (10) mounted on the support (3), coaxial with the damping piston (4), comprising a control pot (11), an axially displaceable control piston (16) arranged in the control pot (11), and - at least one spring arrangement (20) arranged between the control piston (16) and the check valve (5) with at least one first spring element (21), which is axially supported on the one hand directly on the control piston (16) and on the other hand at least indirectly on the check valve (5), bends in the loaded state and introduces a spring force into the control piston (16) and at least indirectly into the check valve (5), wherein the control piston (16) has a height difference (16c) between its one radially outer edge (16a) and its one radially inner edge (16b) facing the radial center of the control piston (16), which defines a maximum deflection height of the first spring element (21),wherein the formal design of the surface (16d) of the control piston (16) facing the first spring element (21) between the radially outer edge (16a) and the radially inner edge (16b) of the control piston (16) is adapted to the formal design of the first spring element (21) in its loaded state, , characterized bythat the height difference (16c) is determined by the fact that the radially outer edge (16a) of the control piston (16) is raised relative to the remaining surface (16d) of the control piston (16) facing the first spring element (21), wherein the raised radially outer edge (16a) has an inner edge (16e) whose formal design is adapted to the formal design of the first spring element (21), which the spring element (21) assumes after its deformation up to the maximum permissible deflection height defined by the height difference (16c) of the control piston (16), wherein the spring element (21) in the loaded state after its deformation up to the maximum permissible deflection height defined by the height difference (16c) of the control piston (16) rests against the inner edge (16e) and the surface (16d),to define the deflection shape of the first spring element (21) and to influence the spring rate of the spring arrangement (20) in a defined manner in the loaded state., [2] Frequency-dependent damping valve arrangement (1) according to claim 1, characterized by in that the first spring element (21) of the spring arrangement (20) comprises an inner edge (21a) facing the carrier (3) and an outer edge (21b) facing away from the carrier (3), wherein the spring element (21) is supported with at least one of the two edges (21a, 21b) axially directly on the control piston (16) and with the other of the two edges (21a, 21b) at least indirectly on the check valve (5), bends in the loaded state and introduces a spring force into the control piston (16) and at least indirectly into the check valve (5). [3] Frequency-dependent damping valve arrangement (1) according to claim 1 or 2, characterized by that the radially outer edge (16a) of the control piston (16) is divided into several segments (27). [4] Frequency-dependent damping valve arrangement (1) according to at least one of the preceding claims, characterized by that the damping valve arrangement (1) comprises at least one additional spacer component (28) which is arranged between the control piston (16) and the first spring element (21). [5] Vibration damper with a frequency-dependent damping valve arrangement (1), characterized by that the frequency-dependent damping valve arrangement (1) is designed according to at least one of the preceding claims.

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