Adjustable vibration damper

Abstract

Adjustable vibration damper (10) according to the Uniflow principle with damping force control, comprising a damper tube housing (12) at least partially filled with damping medium and a damping valve element (14) arranged on the damper tube housing (12) and fluidically connected for damping force control, an inner tube (18) inserted into the damper tube housing (12) via a bottom valve element (16), a piston rod (20) movable longitudinally in the inner tube (18) with a working piston (22), wherein the bottom valve element (16) divides the damper tube housing (12) into a low-pressure working chamber (24) and a high-pressure working chamber (26, 26a, 26b) acted upon by the working piston (22) and a separating piston (40) located in the damper tube housing (12) separates the damping medium in the low-pressure working chamber (24) from a gas volume (42) held in the damper tube housing (12), wherein the bottom valve element (16) has a check valve (50) for the damping medium flow (Q) A ) from the low-pressure working chamber (24) into the high-pressure working chamber (26) and wherein the bottom valve element (16) has a valve element (52) for damping medium flow (Q3) from the high-pressure working chamber (26) into the low-pressure working chamber (24), wherein an inlet opening (28) of the damping valve element (14) is fluidically connected to the high-pressure working chamber (26) and an outlet opening (30) of the damping valve element (14) is fluidically connected to the low-pressure working chamber (24), so that the damping valve element (14) is connected in parallel to the working piston (22).

Description

[0001] The invention relates to an adjustable vibration damper with damping force control, comprising a damper housing tube at least partially filled with damping medium, a damping valve arranged on the damper housing tube and fluidically connected for damping force control, an inner tube inserted into the damper tube housing via a bottom valve element, a piston rod longitudinally movable in the inner tube with a working piston, wherein the bottom valve element divides the damper tube housing into a low-pressure working chamber and a high-pressure working chamber acted upon via the working piston, and an inlet opening of the damping valve element is fluidically connected to the high-pressure working chamber and an outlet opening of the damping valve element is fluidically connected to the low-pressure area.

[0002] Vibration dampers are known in the prior art in which two hydraulically arranged control valves are provided parallel to the working piston. One of these valves is controlled by the damping medium during the compression stroke of the piston rod, and the other is controlled by the damping medium during the rebound stroke of the piston rod. EP 1 538 399 A2 describes control valves housed in separate casings for this purpose. DE 10 2008 015 412 A1 describes a solution in which the two control valves are housed in a common casing and are controlled by the damping medium during the compression or rebound stroke. These vibration dampers are constructed as a two-tube configuration, with an inner tube and a surrounding damper tube casing.

[0003] WO 2021 / 011 516 A1 describes a two-tube damper with a side-mounted collector, an internal intake valve assembly, and a pre-assembled accumulator insert located in the outer casing and connected to the collector via openings. Two control valves mounted externally on the casing separately control the compression and rebound stages.

[0004] From DE 10 2010 011 912 A1 a gas spring damper device with a motor generator pump unit is known, which depending on the direction of rotation supplies hydraulic energy as a pump or recovers damping energy as a generator and makes it electrically usable.

[0005] German patent application DE 10 2010 008 720 A1 discloses a compact gas spring damper device in which the gas equalization chamber and separating piston are located in the working cylinder, and a fixed separating plate divides the second working chamber into two partial working chambers. A hydraulic device couples the first working chamber and both partial working chambers for adjusting the damping / spring characteristics.

[0006] EP 3 569 890 A1 discloses a shock absorber with two electrically continuously controlled valves, one for the compression direction and the other for the rebound direction. The valves operate in series with passive valves and are coupled via a communication chamber to a compression chamber with a gas reservoir and compression piston.

[0007] Furthermore, vibration dampers are known that operate according to the so-called Uniflow principle and are constructed in a 3-pipe configuration. These dampers have only one control valve, which, due to the Uniflow principle, always has unidirectional flow through it, regardless of the compression or rebound stage. While it would be desirable to use only one control valve for vibration dampers in a 2-pipe configuration for the sake of simplification, it would be preferable to implement this control valve in a 2-pipe configuration for vibration dampers based on the Uniflow principle.

[0008] Based on this, the object of the present invention is to provide a vibration damper which, as outlined above, makes use of both forms of embodiment.

[0009] The problem is solved by an adjustable vibration damper according to the Uniflow principle with damping force control, comprising a damper housing tube at least partially filled with damping medium and a damping valve arranged on the damper housing tube and fluidically connected for damping force control, an inner tube inserted into the damper tube housing via a bottom valve element, a piston rod longitudinally movable in the inner tube with a working piston,wherein, according to the invention, a separating piston seated in the damper tube housing separates the damping medium in the low-pressure area from a gas volume held in the damper tube housing, and the bottom valve element divides the damper tube housing into a low-pressure working chamber and a high-pressure working chamber pressurized by the working piston, and an inlet opening of the damping valve element is fluidically connected to the high-pressure working chamber and an outlet opening of the damping valve element is fluidically connected to the low-pressure area, so that the damping valve element is connected in parallel to the working piston, wherein the bottom valve element has a check valve for the flow of damping medium from the low-pressure working chamber to the high-pressure working chamber and wherein the bottom valve element has a valve element for the flow of damping medium from the high-pressure working chamber to the low-pressure working chamber.

[0010] A vibration damper designed according to the invention functions according to the Uniflow principle and is configured as a two-tube system. Furthermore, only one damping valve element or control valve is provided. Overall, this ensures a radially slim design. By arranging a gas volume and separating this gas volume from the low-pressure area, it is possible to dispense with a third cylinder tube.

[0011] Optionally, the gas volume is arranged inside the damping valve element or around the outside of the damper tube.

[0012] An advantageous embodiment of the invention provides that the inner tube is inserted into the damper tube housing via the bottom valve element in such a way that the bottom valve element is inserted circumferentially into the damper tube housing and hydraulically seals against the inner tube. It is advantageous if the inner tube and bottom valve element form an assembly unit and can be inserted together axially into the damper tube housing.

[0013] An advantageous embodiment of the invention provides that the damping valve element is continuously adjustable between a minimum damping setting and a maximum damping setting. This allows different damping characteristics to be set.

[0014] An advantageous embodiment of the invention provides that the damping valve has at least one controllable valve unit via which the damper characteristic can be switched. This allows the number of adjustable damping characteristics to be further increased.

[0015] In a specific embodiment of the invention, it may be provided that the valve unit comprises a manually, electrically or electromagnetically adjustable valve for switching the damper detection.

[0016] An advantageous embodiment of the invention provides that a second valve unit with a defined flow cross-section is connected upstream or downstream of the first valve unit in the flow direction of the damping medium. Furthermore, it is considered advantageous to provide an additional, passive valve unit that is connected in parallel or in series with the first and / or the second valve unit.

[0017] The invention is explained below with further features, details, and advantages with reference to the accompanying figures. The figures merely illustrate exemplary embodiments of the invention. Herein, they show Fig. 1 a schematic representation of a vibration damper according to the invention; Fig. 2 a vibration damper according to Fig. 1 in the rebound stage with a damping valve element in the closed position; Fig. 3 a vibration damper according to Fig. 1 in the rebound stage with a damping valve element in the open position; Fig. 4 a vibration damper according to Fig. 1 in the pressure stage with a damping valve element in the closed position; Fig. 5 a vibration damper according to Fig. 1 in the pressure stage with a damping valve element in the open position and Fig. 6 an alternative design of the damping valve element.

[0018] The Fig. Figure 1 shows, in a predominantly schematic representation, a possible embodiment of a vibration damper 10 according to the invention. The vibration damper 10 is designed in a two-tube configuration and comprises a damper tube housing 12, an inner tube 18, and a damping valve element 14. The inner tube 18 is inserted axially into the damping valve element 14 in a lower region via a bottom valve element 16, the bottom valve element 14 closing the inner tube 18 downwards and sealing circumferentially against an inner circumference of the damper tube housing 12. A space is formed between the damper tube housing 12 and the inner tube 18 inserted therein, which is closed downwards by the bottom valve element 16. The inner tube 18 is filled with damping medium, and a working piston 22, attached to a piston rod 20, is guided axially within the inner tube 18.The direction of movement of the working piston 22 can be defined as a longitudinal direction of the vibration damper 10. The upper end of the damper tube housing 12 is sealed with a piston rod guide (not shown).

[0019] During operation, a high-pressure working chamber 26 is formed within the inner tube 18, with the working piston 22 dividing this chamber into a piston rod-side region 26a and a piston rod-remote region 26b. The high-pressure working chamber 26 extends through openings 44 in the wall of the inner tube 18 into the space between the inner tube 18 and the damper tube housing 12. The high-pressure working chamber 26 is separated from a low-pressure working chamber 26, which forms within the damper tube housing 12 during operation, by the bottom valve element 16. Furthermore, a gas volume 42 is provided in the damper tube housing 12, which is separated from the low-pressure working chamber 26 by a separating piston 40 that is axially movable within the damper tube housing 12.

[0020] A damping valve element 14 is attached to the outside of the damper tube housing 12. Its function in conjunction with the working movement of the working piston 22 is described further below. The damping valve element 14 has an inlet opening 28 and an outlet opening 30 and is fluidically connected to the high-pressure working chamber 26 via the inlet opening 28 and to the low-pressure working chamber 24 via the outlet opening 30, through corresponding bores formed in the damper tube housing 12.

[0021] The damping valve element 14 in the illustrated embodiment comprises a controllable valve unit 34, a second valve unit 36 ​​with a defined flow cross-section, which is connected downstream of the first, controllable valve unit 34 in the flow direction of the damping medium, and a hydraulic intermediate chamber 38 arranged between the two valve units. The damping valve element 14 can be set between an open position and a closed position via the controllable valve unit 34.

[0022] Based on the Fig. 2, Fig. 3, Fig. 4 to Fig. 5 describes the circuit of the damping medium in the vibration damper 10 in the compression stage, the rebound stage and each with open and closed damping valve element 14.

[0023] The Fig. Figure 2 shows the vibration damper 10 in the rebound stage, symbolized by arrow 46 in the area of ​​the piston rod. The damping valve element 14, or the adjustable valve unit 34, is in the closed position. This provides a hard characteristic during operation of the vibration damper 10. The piston rod 20 and the working piston 22 move upwards in the direction of arrow 46. The damping fluid flows through a valve element 48 in the working piston 22 from the piston rod-side area to the area furthest from the piston rod in the high-pressure working chamber 26. The flow of the damping fluid is symbolized by arrow Q1. To compensate for the piston rod volume, damping fluid flows from the low-pressure working chamber 24 through a check valve 50 in the bottom valve element 16 into the high-pressure working chamber 26. This does not generate a damping force. This flow of the damping fluid is symbolized by arrow Q. A .

[0024] The Fig. Figure 3 shows the vibration damper 10 also in the rebound stage, symbolized by arrow 46 in the area of ​​the piston rod. Furthermore, the damping valve element 14, or the adjustable valve unit 34, is in the open position. This provides a soft characteristic during operation of the vibration damper 10. The piston rod 20 and the working piston 22 move upwards in the direction of arrow 46. The damping fluid flows from the piston rod-side area of ​​the high-pressure working chamber 26 via the openings 44, into the space between the inner tube 18 and the damper tube housing 12, and through the inlet opening into the damping valve element 14. The damping fluid exits the damping valve element 14 again via the outlet opening 30 into the low-pressure working chamber 24. The flow of the damping fluid then continues via the check valve 50 in the bottom valve element 16 into the area furthest from the piston rod of the high-pressure working chamber 26.The flow of the damping medium is symbolized by arrow Q2. To compensate for the piston rod volume, damping medium flows from the high-pressure working chamber 24 on the piston rod side through the valve element 48 in the working piston 22 into the high-pressure working chamber 26 further away from the piston rod. This generates a small damping force. This flow of damping medium is symbolized by arrow Q1. In this working area of ​​the vibration damper 10, the damping medium flows mainly through the damping valve element 14, so Q1 << Q2. The separating piston 40 moves upwards to compensate for the volume of the piston rod 20 exiting the damper tube housing 12. The distribution between the flows Q1 and Q2 can be varied by intermediate positions of the valve unit 34 between the open and closed positions, so that different damping characteristics can be set in the rebound stage.

[0025] The Fig. Figure 4 shows the vibration damper 10 in the compression stage, symbolized by arrow 54 in the area of ​​the piston rod. The damping valve element 14, or the adjustable valve unit 34, is in the closed position. This provides a hard characteristic during operation of the vibration damper 10. The piston rod 20 and the working piston 22 move downwards in the direction of arrow 46. The damping fluid flows from the high-pressure working chamber 26 to the low-pressure working chamber 24 via a valve element 52 in the bottom valve element 16. The flow of the damping fluid is symbolized by arrow Q3. A small amount of the damping fluid also flows from the area furthest from the piston rod to the area closer to the piston rod in the high-pressure working chamber 26 via a valve element 54 in the working piston 22. The flow of the damping fluid is symbolized by arrow Q*4.Damping force can be generated via this flow of damping medium.

[0026] The Fig. Figure 5 shows the vibration damper 10 in the compression stage, symbolized by arrow 54 in the area of ​​the piston rod. The damping valve element 14, or the adjustable valve unit 34, is also in the open position. This provides a soft characteristic during operation of the vibration damper 10. The piston rod 20 and the working piston 22 move downwards in the direction of arrow 46. The damping medium flows from the area furthest from the piston rod in the high-pressure working chamber 26, through the valve element 54 into the area closest to the piston rod in the high-pressure working chamber 26, and then through the openings 44 into the space between the inner tube 18 and the damper tube housing 12, and through the inlet opening into the damping valve element 14. The damping medium exits the damping valve element 14 through the outlet opening 30 into the low-pressure working chamber 24. The flow of the damping medium is symbolized by arrow Q2.A small amount of damping fluid flows as flow Q3 through the valve element 52 in the bottom valve element 16 directly from the high-pressure working chamber 26 into the low-pressure working chamber 24. In this working area of ​​the vibration damper 10, the damping fluid flows mainly through the damping valve element 14, so Q3 << Q4. The separating piston 40 moves downwards to equalize the volume of the piston rod 20 entering the damper tube housing 12. The distribution between the flows Q3 and Q4 can be varied by intermediate positions of the valve unit 34 between the open and closed positions, so that different damping characteristics can be set in the compression stage.

[0027] The Fig. Figure 6 shows a simplified embodiment of a damping valve element 14, in which only a controllable valve unit 34 is provided. Reference symbol list 10 vibration dampers 12 damper tube housings 14 Damping valve element 16 Bottom valve element 18 inner tube 20 piston rod 22 working pistons 24 Low-pressure work area 26 High-pressure workroom 26a piston rod-side high-pressure area 26b high-pressure area far from piston rod 28 Entrance opening 30 Exit opening 32 Valve element 34 Valve unit 36 Valve unit 38 Hydraulic intermediate chamber 40 separating pistons 42 Gas volume 44 Opening 46 Rebound stage 48 Valve element 50 Check valve 52 Valve element 54 pressure stage

Claims

[1] Adjustable vibration damper (10) according to the Uniflow principle with damping force control, comprising a damper tube housing (12) at least partially filled with damping medium and a damping valve element (14) arranged on the damper tube housing (12) and fluidically connected for damping force control, an inner tube (18) inserted into the damper tube housing (12) via a bottom valve element (16), a piston rod (20) movable longitudinally in the inner tube (18) with a working piston (22), wherein the bottom valve element (16) divides the damper tube housing (12) into a low-pressure working chamber (24) and a high-pressure working chamber (26, 26a, 26b) acted upon by the working piston (22) and a separating piston (40) located in the damper tube housing (12) separates the damping medium in the low-pressure working chamber (24) from a gas volume (42) held in the damper tube housing (12), wherein the bottom valve element (16) has a check valve (50) for the damping medium flow (Q) A ) from the low-pressure working chamber (24) into the high-pressure working chamber (26) and wherein the bottom valve element (16) has a valve element (52) for damping medium flow (Q3) from the high-pressure working chamber (26) into the low-pressure working chamber (24), wherein an inlet opening (28) of the damping valve element (14) is fluidically connected to the high-pressure working chamber (26) and an outlet opening (30) of the damping valve element (14) is fluidically connected to the low-pressure working chamber (24), so that the damping valve element (14) is connected in parallel to the working piston (22). [2] Adjustable vibration damper (10) according to claim 1, characterized by, that the inner tube (18) is inserted into the damper tube housing (12) via the bottom valve element (16) in such a way that the bottom valve element (16) is inserted into the damper tube housing (12) on its inner circumference and seals hydraulically to the inner tube (18). [3] Adjustable vibration damper (10) according to claim 1, characterized by , that the damping valve element (14) is continuously adjustable between any minimum damping characteristic and any maximum damping characteristic. [4] Adjustable vibration damper (10) according to claim 2, characterized by , that the damping valve element (14) has at least one controllable valve unit (34) via which the damper recognition can be switched. [5] Adjustable vibration damper (10) according to claim 3, characterized by , that the valve unit (34) includes a manually, electrically or electromagnetically adjustable valve for switching the damper detection. [6] Adjustable vibration damper (10) according to claim 4, characterized by , that a second valve unit (36) with a defined flow cross-section is connected upstream or downstream of the first valve unit (34) in the flow direction of the damping medium. [7] Adjustable vibration damper (10) according to claim 4 or 5, characterized by , that a further, passive valve unit is provided, which is connected in parallel or in series with the first and / or the second valve unit (34, 36).

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