Vibration damper with adjustable damping valve device

Abstract

The invention relates to a vibration damper having an adjustable damping valve arrangement, comprising a main valve and a pilot valve, which has an annular pilot valve body and which actuates the main valve by determining the pressure level in a control chamber located on the back side with respect to the annular main valve body, a multi-part annular housing of the adjustable damping valve device forms a piston rod guide for a piston rod that can be moved axially in a working cylinder, the housing comprising a cover, an intermediate housing and a base, the control chamber being spatially separated from the pilot valve body by means of an intermediate wall.

Description

Technical Field

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

[0002] DE 40 24 920 A1 discloses, in an embodiment according to FIG. 11 , a universal shock absorber, whose adjustable damping valve arrangement is arranged in the region of a piston rod guide of the shock absorber or even as a part of the piston rod guide.

[0003] The adjustable damping valve device comprises an excitation coil which exerts a lifting force on the annular pilot valve body against a return spring. The pilot valve body forms a control chamber with the back side of the main valve body, the pressure of which forms a closing force on the main valve body. A flexible valve disc is used as the main valve body, which is clamped at the inner diameter between the upper housing part and the lower housing part. The clamping force is generated by a container tube bent at the edge, which presses the housing of the damping valve device onto the end face of the working cylinder.

[0004] Generally speaking, this damping valve device is characterized by a very simple structure, but the design of the main valve limits the selection of a valve disk as a valve body of the main valve, so that the possible damping force characteristic curve is also limited. Summary of the invention

[0005] An object of the present invention is to provide an adjustable damping valve device capable of realizing a wider range of damping force characteristic curves.

[0006] According to the invention, this object is achieved in that the housing comprises a cover part, an intermediate housing and a base part, wherein the control chamber is spatially separated from the pilot valve body by an intermediate wall.

[0007] Due to the multi-part design of the housing of the damping valve device and the use of the intermediate wall, on the one hand, the force transmission flow is significantly improved when the damping valve device is axially clamped between the reservoir tube and the working cylinder. Independent of this design of the shock absorber, the intermediate wall simplifies the design of the main valve, in particular, whose main valve body no longer has to be designed as a spring disk as described in the prior art.

[0008] In a further advantageous embodiment, the intermediate wall has a plurality of axially protruding pilot valve seat surfaces, between which there is a uniform spacing angle in the circumferential direction. The individual pilot valve seat surfaces simplify the setting of the magnitude of the lifting force acting on the pilot valve body by varying the number and cross-section of the control pressure channels enclosed by the pilot valve seat surfaces. The uniform distribution of the control pressure channels avoids tilting states when the flow passes through the pilot valve body.

[0009] According to an advantageous dependent claim, the intermediate wall has an axial guide section which delimits the control chamber and forms a guide surface for the main valve body. In principle, the main valve body could also slide on a guide surface which is connected, for example, to the base. However, the base could be subject to transverse forces. By using the intermediate wall to separate the components, this effect can be eliminated.

[0010] The present application proposes that the intermediate wall and the axial sleeve of the armature for the pilot valve are designed in one piece, thereby simplifying the angular alignment of the two sections of the intermediate wall, thereby improving the functional reliability of the pilot valve.

[0011] For an easily operable structural unit of the damping valve device during the assembly phase, the sleeve of the intermediate wall and the cover of the housing are connected to one another. The connection is preferably designed as a press fit.

[0012] In order to enable the housing of the damping valve device to perform the function of a piston rod guide as optimally as possible, the base of the housing has a guide sleeve which extends axially in the direction of the cover until it exceeds the intermediate wall. This increases the guide length of the housing, more precisely the guide length of the piston rod guide for the piston rod.

[0013] For the purpose of isolating lateral forces, there is a movement play between the sleeve of the intermediate wall and the guide sleeve of the base.

[0014] For a limited magnetic flux acting on the pilot valve, the sleeve of the intermediate wall is connected to a guide ring, which contacts the housing of the damping valve device in the magnetic flux of the excitation coil for controlling the pilot valve. This prevents a second magnetic flux from acting on the guide sleeve of the base via the cover.

[0015] Furthermore, it can be provided that the flow connection between the piston rod-side working space in the working cylinder and the compensation chamber via the main valve has a nonreturn valve which opens in the flow direction toward the compensation chamber.

[0016] In one embodiment, the opened nonreturn valve is hydraulically connected in series upstream of the main valve in the flow direction starting from the working chamber on the piston rod side. Such a valve arrangement effectively prevents a backflow from the compensation chamber of the shock absorber via the damping valve arrangement into the working chamber on the piston rod side and, through a corresponding design, enables the nonreturn valve to contribute to a greater damping force by forming a kind of front valve of the adjustable damping valve arrangement.

[0017] Alternatively or in combination, the check valve that opens can be hydraulically connected in series with the downstream of the main valve along the flow direction starting from the working chamber on the piston rod side. By this design, no gas can penetrate into the adjustable damping valve from the compensation chamber.

[0018] The check valve, in particular the closing spring of the check valve, is preferably supported on the guide section of the intermediate wall. Thus the operating force and the operating position of the check valve are independent of the setting of the pilot valve, and thus also independent of the setting of the main valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be explained in more detail with reference to the following drawings, wherein:

[0020] Figure 1 shows a schematic diagram of a shock absorber;

[0021] Figure 2 Shown according to Figure 1 Detailed diagram of the damping valve arrangement. DETAILED DESCRIPTION

[0022] Figure 1 The schematic diagram shows a shock absorber 1 having an adjustable damping valve device 3 in a piston rod guide 5 as an end-side termination of a working cylinder 7 filled with a damping medium. A piston 11 on an axially movable piston rod 9 divides the working cylinder 7 into a working chamber 13 on the piston rod side and a working chamber 15 remote from the piston rod. The damping medium expelled from the working chambers 13, 15 is received by a compensation chamber 17 at least partially filled with damping medium. The piston is equipped with valves 19, 21 with different functions. These different functions are highlighted by different types of springs.

[0023] The bottom valve body 23 at the end of the working cylinder 7 opposite the piston rod guide 5 also has two valves 25, 27 with different functions. The damping valve 25 in the bottom valve body is used in particular as a pressure limiting valve, while the valve 27 as a non-return valve ensures that the damping medium flows from the compensation chamber 17 into the working chamber 15 remote from the piston rod during the extension movement of the piston rod.

[0024] The valves 19, 21 in the piston 11 are designed similarly in principle. During the retraction movement of the piston rod 9, the non-return valve 19 in the piston 11 opens, so that the damping medium displaced by the piston rod 9 from the working chamber 15 remote from the piston rod flows through the non-return valve 19 into the working chamber 13 on the piston rod side and then flows through the adjustable damping valve device 3 into the compensation chamber 17. The pressure-limiting valve 25 remains closed until the pressure in the working chamber 15 remote from the piston rod reaches a limit pressure. If this limit pressure is exceeded, the pressure-limiting valve 25 opens and allows outflow directly into the compensation chamber 17.

[0025] During the extension movement of the piston rod, the nonreturn valve 19 in the piston 11 is closed. The valve designed as a pressure limiting valve 21 also closes below the limit pressure. Therefore, the entire volume of damping medium in the annular working chamber 13 on the piston rod side is displaced into the compensation chamber 17 via the adjustable damping valve device 3. As a result, the damping force of the shock absorber 1 in both working directions can be influenced with a single damping valve device 3. In this case, the damping valve device 3 is always flowed through only in the direction starting from the working chamber 13 on the piston rod side.

[0026] Figure 2 The specific structure shows Figure 1 The adjustable damping valve device 3 arranged in the piston rod guide 5 comprises an excitation coil 29 and a magnetic armature 31, which serves as an actuator for a pilot valve 33 having an annular pilot valve body to control a main valve 35. In this compact design, the magnetic armature forms the pilot valve body, which is also annular. However, the magnetic armature and the pilot valve body can also be separate components.

[0027] The pilot valve 33 is actuated by determining the pressure level in a control chamber 39 which is located on the back side of the annular main valve body 37 with respect to the flow from the piston rod-side working chamber 13. The pressure in the control chamber 39 generates a closing force on the main valve body 37.

[0028] The multi-part, annular housing of the adjustable damping valve device 3 forms a piston rod guide 5 for a piston rod 9 that can be axially displaced in a working cylinder 7. The housing 5 or piston rod guide of the damping valve device 3 comprises a cover 41, an intermediate housing 43 and a base 45. The housing 5 is clamped axially between the bent edge 47 of the outer container tube 49 and the working cylinder 7. The working cylinder 7 is radially centered at the shoulder of the base 45. The intermediate housing 43 and the cover 41 are radially in contact with the container tube 49. The cover 41 carries a piston rod seal 51 in the area of ​​the through hole for the piston rod 9. The seal 53 is optionally arranged at the outer circumference of the cover 41, which is intended to prevent damping medium and / or gas from escaping from the compensation chamber 17 as a final barrier.

[0029] In addition to the cover 41, the intermediate housing 43 and the base 45, the housing 5 further includes an intermediate wall 55. The intermediate wall 55 spatially separates the main valve 35 from the pilot valve 33, in particular, separates the control chamber 39 from the pilot valve body 31.

[0030] The intermediate wall 55 has a plurality of axially raised pilot valve seat surfaces 57, between which there are equal spacing angles in the circumferential direction. In principle, the main valve body 37 can slide on the base 45. The intermediate wall 55 preferably has an axial guide section 59, which radially inwardly delimits the control chamber 39 and forms a guide surface for the main valve body 37.

[0031] Furthermore, the intermediate wall 55 and the axial sleeve 61 for the pilot valve body 31 are designed in one piece. The sleeve 61 of the intermediate wall 55 is in turn connected to a guide ring 63, which contacts the housing 5 of the damping valve device 3 in the magnetic flux of the excitation coil 29 for controlling the pilot valve 33. As a result, a stepped cross section is generated at the intermediate wall 55. The sleeve 61 of the intermediate wall 55 and the cover 41 of the housing 5 are connected to each other. As a result, the entire "intermediate wall" component is axially fixed in the damping valve device. In addition, the inner seal 65 and the outer seal 67 prevent the damping medium from flowing out of the pilot valve along the cover 41. The cover 41 preferably forms a magnetic resistance portion so that the magnetic flux emitted from the excitation coil takes the best route through the pilot valve body 31. Alternatively, for example, a magnetic resistance portion located between the cover 41 and the base 45 can be conceived.

[0032] The base 45 of the housing 5 has a guide sleeve 69 which extends axially in the direction of the cover 41 until it exceeds the intermediate wall 55. There is a movement gap 70 between the guide section 59 of the intermediate wall 55 and the guide sleeve 69 of the base, which isolates the elastic movement of the guide sleeve 69 relative to the guide section 59 of the intermediate wall 55. A seal 71 can also be provided here to prevent leakage at the pilot valve 33. A bearing sleeve 73 is arranged between the cover 41 and the end-side shoulder of the guide sleeve 69. As a result, there is a large guide length for the piston rod 9 at a very large distance of the piston 11 relative to the bearing sleeve 73.

[0033] In order to connect the pilot valve 33 and the main valve 35 to the piston rod-side working chamber 13 and the compensation chamber 17 , a flow connection 75 with at least one nonreturn valve 77 , 79 is provided.

[0034] A non-return valve 77 which opens in the direction of flow from the working chamber 13 on the piston rod side toward the compensation chamber 17 is hydraulically connected in series upstream of the main valve 35. If the goal is that no gas and / or damping medium should flow from the compensation chamber 17 via the main valve 35 into the working chamber 13 on the piston rod side, the size of the non-return valve 77 can be designed to have a very small opening force. However, the non-return valve 77 can also be provided with a larger opening force, so that the non-return valve 77 always acts as an additional passive damping valve. The non-return valve 77 is designed as a central valve, and its valve seat surface is designed at the base 45. The closing spring 89 of the non-return valve 77 is supported on the end face of the guide section 59 of the intermediate wall 55 that remains stationary. As a result, the operating characteristics of the non-return valve 77 are independent of the operating characteristics of the main valve body 37, which can also be used as a supporting element for the closing spring due to the spatial proximity.

[0035] If only a return flow of gas and / or damping medium from the compensation chamber 17 into the piston rod-side working chamber 13 is to be prevented, a nonreturn valve 79 which opens hydraulically in series downstream of the main valve 35 in the flow direction from the piston rod-side working chamber 13 can be connected.

[0036] When flow from the working chamber 13 on the piston rod side flows through the adjustable damping valve arrangement, the optional non-return valve 77 opens, whereby damping medium is applied to the main valve body 37 at its lower side in the direction of the non-return valve 77 via at least one connecting opening in the base 45 as part of the flow connection 75. The main valve body 37 has at least one control opening 81, which connects the control chamber 39 to the lower side of the main valve body 37. However, damping medium can escape from the control chamber 39 via the outflow opening 83 surrounded by the pilot valve seat surface 57, depending on the raised position of the pilot valve body 31, along the outflow channel 85 into the compensation chamber 17. Due to the interaction of the flow through the main valve body 37 and the outflow cross section at the outflow opening 83 set by the pilot valve 33, a closing pressure is generated in the control chamber 39, which exerts a defined closing force on the main valve body 37. Between the main stage valve seat surface 87 and the main stage valve body 37 lifted away from it, the damping medium can flow out into the compensation chamber 17 while generating a damping force.

[0037] List of reference numerals:

[0038] 1 Shock absorber

[0039] 3 Adjustable damping valve device

[0040] 5 Piston rod guide / housing for adjustable damping valve unit

[0041] 7 Working cylinder

[0042] 9 Piston rod

[0043] 11 Piston

[0044] 13 Working chamber on the piston rod side

[0045] 15 Working chamber away from piston rod

[0046] 17 Compensation Room

[0047] 19 Check valve

[0048] 21 Pressure limiting valve

[0049] 23 Foot valve body

[0050] 25 Pressure limiting valve

[0051] 27 Check valve

[0052] 29 Excitation coil

[0053] 31 Magnetic armature

[0054] 33 Pilot valve

[0055] 35 Main valve

[0056] 37 Main valve body

[0057] 39 Control Room

[0058] 41 cover

[0059] 43 Intermediate housing

[0060] 45 base

[0061] 47 Edge of container tube

[0062] 49 Container tube

[0063] 51 Piston rod seal

[0064] 53 Seals

[0065] 55 Middle wall

[0066] 57 Pilot valve seat surface

[0067] 59 Boot Segment

[0068] 61 Sleeve

[0069] 63 Guide ring

[0070] 65 Inner seal

[0071] 67 Outer seal

[0072] 69 Guide sleeve

[0073] 70 Movement Gap

[0074] 71 Seals

[0075] 73 Support sleeve

[0076] 75 Mobile connections

[0077] 77 Check valve

[0078] 79 Check valve

[0079] 81 Control opening

[0080] 83 Outflow opening

[0081] 85 Outflow channel

[0082] 87 Main valve seat surface

[0083] 89 Closing spring of non-return valve.

Claims

1. A shock absorber (1) with an adjustable damping valve device (3), the shock absorber comprising a main valve (35) and a pilot valve (33), the pilot valve having an annular pilot valve body (31), the pilot valve (33) controlling the main valve (35) by determining a pressure level in a control chamber (39) located on the rear side relative to the annular main valve body (37), wherein: The multi-piece annular housing (5) of the adjustable damping valve device (3) forms a piston rod guide for a piston rod (9) that can be axially moved in a working cylinder (7), characterized in that the housing (5) includes a cover (41), an intermediate housing (43) and a base (45), wherein the control chamber (39) is spatially separated from the pilot valve body (31) by an intermediate wall (55).

2. The vibration absorber (1) according to claim 1, characterized in that The intermediate wall (55) has a plurality of axially protruding pilot valve seat surfaces (57), and the pilot valve seat surfaces are spaced at the same angle in the circumferential direction.

3. The vibration absorber (1) according to claim 1 or 2, characterized in that: The intermediate wall (55) has an axial guide section (59) which delimits the control chamber (39) and forms a guide surface for the main valve body (37).

4. The vibration absorber (1) according to at least one of claims 1 to 3, characterized in that The intermediate wall (55) and an axial sleeve (61) for the armature of the pilot valve (33) are designed in one piece.

5. The vibration absorber (1) according to claim 4, characterized in that The sleeve (61) of the intermediate wall (55) and the cover portion (41) of the housing (5) are connected to each other.

6. The vibration absorber (1) according to at least one of claims 1 to 5, characterized in that The base part (45) of the housing (5) has a guide sleeve (69) which extends axially in the direction of the cover part (41) until it exceeds the intermediate wall (55).

7. The vibration absorber (1) according to claim 6, characterized in that There is a movement play (70) between the sleeve (61) of the intermediate wall (55) and the guide sleeve (69).

8. The vibration absorber (1) according to at least one of claims 4 to 7, characterized in that The sleeve (61) of the intermediate wall (55) is connected to a guide ring (63), which contacts the housing (5) of the damping valve device (3) within the magnetic flux of the excitation coil (29) for controlling the pilot valve (33).

9. The vibration absorber (1) according to at least one of claims 1 to 8, characterized in that A flow connection (75) between a piston rod-side working chamber (13) and a compensation chamber (17) in the working cylinder (7) via the main valve (35) has a nonreturn valve (77, 79) which opens in the flow direction toward the compensation chamber (17).

10. The vibration absorber (1) according to claim 9, characterized in that The open nonreturn valve (77) is hydraulically connected in series upstream of the main valve (35) in the flow direction starting from the working chamber (13) on the piston rod side.

11. The vibration absorber (1) according to claim 9, characterized in that The open nonreturn valve (79) is hydraulically connected in series downstream of the main valve (35) in the flow direction starting from the working chamber (13) on the piston rod side.

12. The vibration absorber (1) according to claim 9, characterized in that The non-return valve (77) is supported on the guide section (59) of the intermediate wall (55).

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