Adjustable damping valve device for adjustable vibration damper

Abstract

The invention relates to an adjustable damping valve arrangement for a shock absorber, the damping valve arrangement being connected to a working chamber on the piston rod side of a working cylinder of the shock absorber and to a working chamber remote from the piston rod, the damping valve arrangement having a main stage valve and a pilot valve hydraulically controlling the main stage valve, the pilot valve having a control chamber, the pressure level of the control chamber is influenced by the throttle cross section of the pilot valve, and wherein the pilot valve body has a pressure-bearing surface in the lifting direction thereof, the pressure-bearing surface being in contact with the throttle cross section of the pilot valve, either for a flow from the working chamber remote from the piston rod or for a flow from the working chamber on the piston rod side. The pilot valve has a pressure-bearing surface which generates a lifting force in combination with the pressure in the control chamber, and wherein the pilot valve has a second pressure-bearing surface which additionally acts in the closing direction of the pilot valve for the flow originating from one of the two working chambers.

Description

Technical Field

[0001] The invention relates to an adjustable damping valve arrangement for an adjustable shock absorber according to the preamble of claim 1 . Background Art

[0002] Document DE 10 2008 041 735 A1 describes a damping valve arrangement for an adjustable shock absorber, in which a main-stage valve is hydraulically controlled by a pilot valve. The pilot valve regulates the pressure level in at least one control chamber, which is connected to the main-stage valve body at the rear. The pressure in the control chamber exerts a hydraulic closing force on the main-stage valve body. When designing and dimensioning this damping valve arrangement, the pressure-bearing surfaces on the main-stage valve in the opening and closing directions are designed to have a specific area ratio relative to each other. Other parameters include the cross-sectional area of ​​the pressure-bearing surface in the lifting direction of the pilot valve and the closing force of the pilot valve's closing spring. Furthermore, the throttling between the working chamber and the control chamber can be varied. Summary of the Invention

[0003] The object of the present invention is to provide a further usable setting parameter for a damping valve arrangement.

[0004] According to the invention, this object is achieved in that the pilot valve has, for a throughflow originating from one of the two working chambers, a second pressure-bearing surface which additionally acts in the closing direction of the pilot valve.

[0005] For flow originating from one of the working chambers, the pilot valve is loaded not only on the pressure-bearing surface in the lifting direction but also, in the same flow direction, on the pressure-bearing surface in the closing direction. However, for flow originating from the other working chamber of the shock absorber, only the pressure-bearing surface in the lifting direction of the pilot valve is used. This asymmetry of the pressure-bearing surfaces has the following advantages: for example, compared to so-called extension damping (in which the piston rod extends out of the working cylinder), comfort is enhanced during the compression of the shock absorber, without compromising driving safety. The use of the pressure-bearing surface on the pilot valve further enhances the relative compactness of the main stage valve.

[0006] In another advantageous design, the second pressure-bearing surface cooperates with a second control chamber of the pilot valve. The independent control chamber in the damping valve device isolates a spatial region in the damping valve device that should not or does not need to perform a hydraulic function for the pilot valve.

[0007] To prevent the pilot valve from automatically closing under extreme flow conditions, the second control chamber is operatively connected to a pressure-limiting valve. This limits the closing force component on the pilot valve. The opening point of the pressure-limiting valve can also be used as a control parameter to adapt the damping valve arrangement and, therefore, the shock absorber, to a specific vehicle.

[0008] In order to realize the present invention in a structurally simple manner, the pilot valve body has a guide pin, wherein the guide pin has a second pressure-bearing surface.

[0009] In this case, the guide pin of the pilot valve body engages in a through-opening of a partition wall within the damping valve arrangement, and the second control chamber is at least partially formed by the partition wall.

[0010] Furthermore, the partition wall separates the hydraulic chamber with the pilot valve and the main stage valve from the actuator chamber of the valve housing of the damping valve arrangement and thus forms the center bottom of the valve housing.

[0011] For further functionality, the dividing wall comprises a channel system connecting one working chamber of the working cylinder with the second control chamber.The dividing wall can be a simple, relatively flat annular disk.

[0012] In this case, it is provided that the pressure-limiting valve is connected to the channel system. Thus, the extension of the control chamber can be independent of the structural design of the pressure-limiting valve.

[0013] Furthermore, it is advantageous if the partition wall is a functional component of the pressure-limiting valve. This allows the pilot valve to be geometrically optimized for the control function of the main stage valve.

[0014] According to an advantageous dependent claim, the non-return valve disk of the pressure-limiting valve is supported on a valve seat surface of the partition wall. The pressure-limiting valve is designed as a seat valve and therefore requires only a small axial installation space. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be described in more detail with reference to the following drawings.

[0016] in:

[0017] Figure 1 shows a longitudinal section of an adjustable damping valve arrangement; and

[0018] Figure 2 Shown according to Figure 1 Detailed view of the area of ​​the pilot valve. DETAILED DESCRIPTION

[0019] Figure 1 A cross section through an adjustable damping valve arrangement 1 for a shock absorber 3 is shown. In this exemplary embodiment, the damping valve arrangement 1 is located in a damping valve housing 5 on an axially displaceable piston rod 7 within a working cylinder 9 of the shock absorber 1. However, the damping valve housing 5 and thus the damping valve arrangement 1 can also be arranged spatially outside the shock absorber 3 and hydraulically connected, for example, via a line or hose connection.

[0020] The damping valve arrangement 1 comprises an electromagnetic actuator 11 with a solenoid coil 13 and an armature 15 which acts at its end on a pilot valve body 17 of a pilot valve 19 . The force of the solenoid coil 13 acts against at least one return spring 21 .

[0021] The pilot valve 19 serves to hydraulically actuate a main stage valve 23 , via which a piston rod-side working chamber 25 and a piston rod-remote working chamber 27 in the working cylinder 9 are connected to one another. Figure 1 The radial connecting channels 29 within the valve housing ring 31, a component of the damping valve housing 5, are shown. These connecting channels connect the piston rod-side working chamber 25 to the main stage valve 23. Passive damping valves 33 and 35 are arranged between the working chamber 27 remote from the piston rod and the main stage valve 23 for each flow direction of the damping valve arrangement 1. The two passive damping valves 33 and 35 can be used selectively. Regardless of the working direction of the piston rod 7 within the shock absorber 3, the damping force-determining volume flow of the damping medium in the working cylinder 9 is discharged via the connecting channels 29, the main stage valve 23, and the two passive damping valves 33 and 35. Furthermore, a sealing piston 36, as a functional section of the damping valve housing 5, ensures the spatial separation of the two working chambers 25 and 27.

[0022] The main-stage valve 23 comprises a main-stage valve body 37 and a main-stage valve seat surface 39 formed by a valve ring 41 within the valve housing ring 31. The main-stage valve body 37 is guided axially displaceably within a stepped opening 43 of the valve housing ring 31 and, together with the stepped opening of the valve housing, forms a first control chamber 45. This first control chamber 45 is connected to the radial connection channel 29 via at least one first throttle channel 47, wherein a pressure drop exists between the pressure in the connection channel 29 and the pressure in the first control chamber 45 due to the throttling effect of the throttle channel 47.

[0023] The main stage valve body 37 has a valve pin 49 pointing toward the pilot valve 19 and having a pilot valve seat surface 51 for the pilot valve body 17 on the end side. (See Figure 2 ) The valve pin shaft 49 is hollow and has at least one radial interface opening 53, which leads to an axial channel 55 as part of the first control chamber 45. The first control chamber has a second throttling channel 59 in the intermediate wall 57 along the flow direction to the pilot valve 19. The second throttling channel connects the first control chamber 45 to the second control chamber 61 between the intermediate wall 57 and the pilot valve 19 and ensures a further pressure drop between the first control chamber 45 and the second control chamber 61.

[0024] At least one axial channel 63, which has a throttling function similar to that of the first throttle channel 47 and connects a connecting chamber 65 of the damping valve arrangement 1 to the first control chamber 45, extends within the main stage valve body 37. Both the first throttle channel 47 and the axial channel 63 between the connecting chamber 65 and the first control chamber 45 are equipped with non-return valves 67 and 69, which open in the inflow direction toward the first control chamber 45. This prevents a hydraulic short-circuit of the pilot valve 19 via the first control chamber 45.

[0025] The lifting stroke of the pilot valve body 17 from the pilot valve seat surface 51 defines a throttle cross section between the pilot valve body 17 and the pilot valve seat surface 51. This throttle cross section, in turn, determines the pressure levels in the first control chamber 45 and the second control chamber 61. The pressures in the two control chambers 45 and 61 multiplied by the axial pressure-bearing area of ​​the main-stage valve body 37 yield an effective closing force acting on the main-stage valve body 37. Given a predetermined operating motion of the shock absorber 3, this effective closing force determines the damping force of the shock absorber 3.

[0026] The damping medium passing through the pilot valve 19 reaches the return chamber 71 of the pilot valve 19 between the bottom of the valve housing ring 31 and the actuator 11, which is connected to a non-return valve assembly 73, which includes a non-return valve ring 75, which is equipped with at least one non-return valve disk 77 on both sides; 79 ( Figure 2 ). The check valve ring 75 is a component that is separate and replaceable from the valve housing ring 31. The check valve discs 77; 79 on both sides are combined with the check valve ring 75 to form two check valves 81; 83 to control the control volume flow flowing out of the pilot valve 19 into the two working chambers 25; 27 of the working cylinder 9. Along the flow direction from the check valve assembly 73 to the working chamber 25 on the piston rod side, the damping valve housing 5 has at least one connecting opening 85 that is radial in this example. In order to connect the pilot valve 19 with the working chamber 27 away from the piston rod, the valve housing ring 31 has a channel system 87 leading to the interface chamber 65. When the fluid flows from one of the two working chambers 25; 27 into the check valve assembly 73, the check valve 81; 83 that flows directly through, that is, bypasses the pilot valve 19, is closed.

[0027] The check valve ring 75 is centered on the valve housing ring 31 via its central through-opening 89. Figure 2As shown, the non-return valve ring 75 has an annular groove 91 facing the return chamber 71, which in turn includes an axial connection opening 93 leading to the channel system 87 in the valve housing ring 31. The annular groove 91 is radially delimited by two annular support surfaces 95, 97 for the non-return valve disk 77. The inner support surface 97 is interrupted by at least one radial channel 99, which connects the annular groove 91 to a radially inner connection channel 101. The connection channel 101 is directly connected to the return chamber 71 of the pilot valve 19.

[0028] The lifting movement of the non-return valve disk 79 for the channel system 87 in the valve housing ring 31 is limited by the valve housing ring 31. A partition wall 103 is used for the lifting movement of the non-return valve disk 77 on the top side of the non-return valve ring 75, which additionally fixes the non-return valve ring 75 axially within the damping valve housing 5.

[0029] In addition to the pressure-bearing surface of the pilot valve 19 or the pilot valve body 17, which acts in the lifting direction and is defined by the pilot valve seat surface 51, the pilot valve 19 has a second pressure-bearing surface 105, which additionally acts in the closing direction of the pilot valve 19, for the flow through the working chamber 25 on the piston rod side. The second pressure-bearing surface 105 cooperates with a second control chamber 107 of the pilot valve 19.

[0030] The pilot valve body 17 has a guide pin 109 facing the actuator 11, which has an annular second pressure-bearing surface 105. The second pressure-bearing surface 105 is formed by a circumferential shoulder of the guide pin 109. The guide pin 109 of the pilot valve body 19 engages in a through-opening 111 of a partition wall 103 fixed to the valve housing 5 within the damping valve arrangement 1. The second control chamber 107 is at least partially formed by the partition wall 103. The through-opening 111 within the partition wall 103 has a step that forms the bottom 113 of the second control chamber 107. Furthermore, the partition wall 103 separates the valve chamber containing the pilot valve 19 and the main stage valve 23 from an actuator chamber 117 within the valve housing 5 of the damping valve arrangement 1. The partition wall 103 also includes a channel system 119 that connects the piston rod-side working chamber 25 of the working cylinder 9 with the second control chamber 107.

[0031] To limit the closing force on the pilot valve 19, the second control chamber 107 is operatively connected to a pressure-limiting valve 121. The pressure-limiting valve 121 is connected to a channel system 119 in the partition wall 103. The partition wall 103 is a functional component of the pressure-limiting valve 121. A valve disk 123 of the pressure-limiting valve 121 is supported on a valve seat surface 125 of the partition wall 103.

[0032] When damping medium flows into the damping valve arrangement 1 due to compression in the working chamber 27 remote from the piston rod, it passes through the passive damping valve 35 and, in the connecting chamber 65, ensures that the main-stage valve body 37 is pressurized within the pressure-bearing surface defined by the main-stage valve seat surface 39. The control volume flows via the axial channel 63 and the open check valve 69 to the first control chamber 45 and further via the second throttle channel 59 to the second control chamber 61 within the valve pin 49. The pressure in the second control chamber 61 acts in the lifting direction of the pilot valve body 17. The pressure in both control chambers 45 and 61 exerts a hydraulic closing force on the main-stage valve body 37. The control volume flows via the pilot valve 19 and the check valve disk 77 lifted from the check valve ring 75 through the connecting opening 85 into the working chamber 27 on the piston rod side.

[0033] Damping medium acting on the non-return valve 83 via the channel system 87 in the valve housing ring 31 closes the non-return valve 83. In this case of inflow into the damping valve arrangement 1, the non-return valve 67 in the main stage valve body 37 is also closed.

[0034] When the damping valve arrangement 1 is fed from the piston rod-side working chamber 25, the displaced damping medium accumulates on the annular surface of the mainstage valve body 37, which extends radially outside the mainstage valve seat surface 39 of the mainstage valve 23 and within the stepped opening 43 of the valve housing ring 31. This pressure also creates a lifting force on the mainstage valve body. The first control chamber 45 is also hydraulically pressurized in parallel via the first throttle channel 47, which results in a pressure increase in the second control chamber 61. This pressure increase, together with the pressure increase in the first control chamber 45, generates a closing force on the mainstage valve body 37. The control volume flow that flows through the pilot valve 19 into the return chamber 71 then also reaches the connecting channel 101, enters the annular groove 91 via the at least one radial channel 99, and can then flow out, in conjunction with the channel system 87, through the connecting opening 93 into the connecting chamber 65 and further through the passive damping valve 33 into the working chamber 27 distal to the piston rod. Here, the check valve 81 is also closed toward the piston rod-side working chamber 25 by reverse flow from the piston rod-side working chamber 25, thereby achieving rectification of the control volume flow in the opening direction through the pilot valve 19 by using a total of four check valves 67; 69; 81; 83.

[0035] In addition, a second control volume flow flows from the piston rod-side working chamber 25 to the pilot valve 19. This second control volume flow enters the channel system 119 in the partition wall 103 via the connecting opening 85 and is supplied to the second control chamber 107 of the pilot valve 19. The pressure in the second control chamber 107 generates a closing force on the pilot valve 19. Consequently, the pressure in the control chamber 61 in the guide pin 47 of the main stage valve body 23 and the pressure in the second control chamber 107 compensate for each other. If the pressure level in the second control chamber 107 exceeds a defined limit, the valve disk 123 of the pressure-limiting valve 121 lifts, allowing the connection opened in the return chamber 71 of the pilot valve 19 to be discharged from the control chamber 61 via the channel system 87 to the connection chamber 65, along with the first control volume flow.

[0036] List of reference numerals:

[0037] 1 Adjustable damping valve device

[0038] 3 shock absorbers

[0039] 5 Damping valve housing

[0040] 7 Piston rod

[0041] 9 working cylinders

[0042] 11 Actuator

[0043] 13 Excitation coil

[0044] 15 Armature

[0045] 17 Pilot valve body

[0046] 19 Pilot valve

[0047] 21 Return spring

[0048] 23 Main stage valve

[0049] 25 Working chamber on the piston rod side

[0050] 27 Working chamber away from the piston rod

[0051] 29 radial interface channels

[0052] 31 Valve housing ring

[0053] 33 Passive Damping Valve

[0054] 35 Passive Damping Valve

[0055] 36 pistons

[0056] 37 Main stage valve body

[0057] 39 Main stage valve seat surface

[0058] 41 valve ring

[0059] 43 Stepped opening of valve housing ring

[0060] 45 First control chamber

[0061] 47 First throttle channel

[0062] 49 valve pin

[0063] 51 Pilot valve seat surface

[0064] 53 interface opening

[0065] 55 Axial channel

[0066] 57 Middle wall

[0067] 59 Second throttle channel

[0068] 61 Second control chamber

[0069] 63 Axial channel

[0070] 65 Interface chamber

[0071] 67 Check valve

[0072] 69 Check valve

[0073] 71 Reflow Chamber

[0074] 73 Check valve assembly

[0075] 75 Check valve ring

[0076] 77 Check valve disc

[0077] 79 Check valve disc

[0078] 81 Check valve

[0079] 83 Check valve

[0080] 85 connection opening

[0081] 87-channel system

[0082] 89 through opening

[0083] 91 Annular groove

[0084] 93 interface opening

[0085] 95 support surface

[0086] 97 Support surface

[0087] 99 radial channels

[0088] 101 interface channel

[0089] 103 partition wall

[0090] 105 second pressure surface

[0091] 107 Second Control Chamber

[0092] 109 pilot valve body guide pin

[0093] 111Through opening of partition wall

[0094] 113 The bottom of the second control chamber of the pilot valve

[0095] 115 Valve chamber of damping valve device

[0096] 117 actuator chamber

[0097] 119 Passage system within the partition wall

[0098] 121 Pressure limiting valve for the second control chamber

[0099] 123 valve disc of pressure limiting valve

[0100] 125 Valve seat surface of the pressure limiting valve.

Claims

1. An adjustable damping valve device (1) for a shock absorber (3), wherein: The damping valve device (1) is connected to a working chamber (25) on the piston rod side and a working chamber (27) remote from the piston rod of a working cylinder (9) of the shock absorber (3), wherein the damping valve device (1) comprises a main stage valve (23) and a pilot valve (19) for hydraulically controlling the main stage valve (23), wherein the pilot valve (19) comprises a control chamber (61), the pressure level of which is influenced by the throttling cross section of the pilot valve (19), wherein the pilot valve body ( 17) has a pressure-bearing surface along its lifting direction, and whether for the flow originating from the working chamber (27) away from the piston rod or for the flow originating from the working chamber (25) on the piston rod side, the pressure-bearing surface generates a lifting force in combination with the pressure in the control chamber (61), characterized in that the pilot valve (19) has a second pressure-bearing surface (105) that acts additionally along the closing direction of the pilot valve for the flow originating from one of the two working chambers (25; 27).

2. The adjustable damping valve device (1) according to claim 1, characterized in that: The second pressure-bearing surface (105) cooperates with the second control chamber (107) of the pilot valve (19).

3. The adjustable damping valve device (1) according to claim 2, characterized in that: The second control chamber (107) is operatively connected to a pressure-limiting valve (121).

4. The adjustable damping valve arrangement (1) according to at least one of claims 1 to 3, characterized in that The pilot valve body (17) has a guide pin (109), wherein the guide pin (109) has the second pressure-bearing surface (105).

5. The adjustable damping valve device (1) according to claim 3, characterized in that: The guide pin (109) of the pilot valve body (17) extends into a through opening (111) of a partition wall (103) in the damping valve device (1), and the second control chamber (107) is at least partially formed by the partition wall (103).

6. The adjustable damping valve device (1) according to claim 5, characterized in that: The partition wall (103) separates a valve chamber (115) having the pilot valve (19) and the main stage valve (23) from an actuator chamber (117) of the valve housing (5) of the damping valve device (1).

7. The adjustable damping valve device (1) according to claim 5 or 6, characterized in that: The partition wall (103) comprises a channel system (119) which connects the working chamber (25; 27) of the working cylinder (9) with the second control chamber (107).

8. The adjustable damping valve device (1) according to claim 7, characterized in that: The pressure-limiting valve (121) is connected to the channel system (119).

9. The adjustable damping valve device (1) according to claim 8, characterized in that: The partition wall (103) is a functional component of the pressure-limiting valve (121).

10. The adjustable damping valve device (1) according to claim 9, characterized in that: The valve disk (123) of the pressure-limiting valve (121) is supported on a valve seat surface (125) of the partition wall (103).

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