Controllable damper

Abstract

The present invention relates to a controllable shock absorber having damping force control and comprising a shock absorber housing tube at least partially filled with a damping medium, a damping valve for damping force control disposed on the shock absorber housing tube and fluidly connected to the shock absorber housing tube, an inner tube introduced into the shock absorber housing tube via a bottom valve element, and a piston rod capable of longitudinal movement within the inner tube and having a working piston.

Description

Technical Field

[0001] This invention relates to a controllable shock absorber having a damping force control system. The controllable shock absorber includes a shock absorber housing tube at least partially filled with a damping medium, and a damping valve for controlling the damping force disposed on and fluidly connected to the shock absorber housing tube; it has an inner tube inserted into the tubular shock absorber housing via a bottom valve element; and it has a piston rod capable of longitudinal movement within the inner tube and having a working piston.

[0002] The bottom valve element divides the tubular shock absorber housing into a low-pressure chamber and a high-pressure chamber acted upon by the working piston. The inlet opening of the damping valve element is fluidly connected to the high-pressure chamber, and the outlet opening of the damping valve element is fluidly connected to the low-pressure region. Background Technology

[0003] Prior art discloses a shock absorber in which two control valves are arranged hydraulically in parallel with the working piston. During the retraction motion of the piston rod, the damping medium flows through one of the control valves in the compression phase, and during the extension motion of the piston rod, it flows through the other control valve in the rebound phase. To this end, EP 1 538 399A1 provides control valves, each housed in a separate housing. DE 10 2008 015 412 A1 describes a solution in which two control valves are housed in a common housing and are passed through by a suitable inflow in either the compression or rebound phase. These shock absorbers are constructed in a 2-tube configuration, having an inner tube and a tubular shock absorber housing surrounding the inner tube. Furthermore, shock absorbers operating according to the "unidirectional flow" principle and constructed in a 3-tube configuration are known. In this case, only one control valve is provided, and due to the unidirectional flow principle, the flow is always unidirectional, regardless of the compression and rebound phases. Therefore, while it is desirable to install only one control valve in the case of a 2-tube configuration shock absorber for the sake of simplicity, it is also desirable to install only one control valve in the case of a shock absorber based on the unidirectional flow principle in the 2-tube configuration. Summary of the Invention

[0004] Therefore, the object of the present invention is to provide a shock absorber, which, as described above, utilizes two embodiments.

[0005] This objective is achieved by a controllable shock absorber having a damping force control system, the controllable shock absorber comprising: a shock absorber housing tube and a damping valve element for damping force control, the tubular shock absorber housing being at least partially filled with a damping medium, the damping valve element being arranged on and fluidly connected to the shock absorber housing tube, an inner tube inserted into the tubular shock absorber housing via a bottom valve element, a piston rod capable of longitudinal movement within the inner tube and having a working piston, wherein, according to the invention, a separation piston located within the tubular shock absorber housing separates the damping medium in the low-pressure chamber from the gas volume held within the tubular shock absorber housing, and the bottom valve element divides the tubular shock absorber housing into a low-pressure chamber and a high-pressure chamber acted upon by the working piston, and the inlet opening of the damping valve element is fluidly connected to the high-pressure chamber, and the outlet opening of the damping valve element is fluidly connected to the low-pressure chamber, such that the damping valve element is connected in parallel with the working piston.

[0006] The shock absorber configured according to the present invention operates based on the principle of unidirectional flow and is designed with a 2-tube configuration. Furthermore, only one damping valve element or control valve is provided. Therefore, a radially slender construction is generally ensured. By arranging the gas volume and separating it from the low-pressure region, the third cylinder tube can be omitted.

[0007] In an advantageous embodiment of the invention, the gas volume is arranged inside the damping valve element or on the outer circumference of the damping tube.

[0008] An advantageous embodiment of the invention envisions an inner tube inserted into a tubular shock absorber housing via a bottom valve element, such that the bottom valve element is inserted onto the inner circumference of the tubular shock absorber housing and forms a hydraulic seal with the inner tube. Advantageously, the inner tube and the bottom valve element form a mounting unit and can be inserted together into the tubular shock absorber housing in the axial direction.

[0009] An advantageous embodiment of the invention envisions that the damping valve element can be continuously adjusted between minimum and maximum damping characteristics. This allows for the setting of different damping characteristics.

[0010] An advantageous embodiment of the invention envisions a damping valve having at least one controllable valve unit, by means of which the damping characteristics can be switched. This further increases the number of settable damping characteristics.

[0011] In a particular embodiment of the present invention, the valve unit may be configured to include a manually adjustable valve, an electrically adjustable valve, or a solenoid adjustable valve for switching damping characteristics.

[0012] Advantageous embodiments of the invention envision a second valve unit having a defined flow cross-section connected upstream or downstream of the first valve unit along the flow direction of the damping medium. Furthermore, it is advantageous to provide additional passive valve units connected in parallel or in series with the first and / or second valve units. Attached Figure Description

[0013] Further features, details, and advantages of the invention will now be explained with reference to the accompanying drawings. The drawings illustrate only illustrative embodiments of the invention. More specifically:

[0014] Figure 1 A schematic diagram of a shock absorber according to the present invention is shown;

[0015] Figure 2 It shows that according to Figure 1 During the rebound phase, the damping valve element of the shock absorber is in the closed position.

[0016] Figure 3 It shows that according to Figure 1 During the rebound phase, the damping valve element of the shock absorber is in the open position.

[0017] Figure 4 It shows that according to Figure 1 During the compression phase, the damping valve element of the shock absorber is in the closed position.

[0018] Figure 5 It shows that according to Figure 1 During the compression phase, the damping valve element of the shock absorber is in the closed position; and

[0019] Figure 6 An alternative embodiment of the damping valve element is shown. Detailed Implementation

[0020] Figure 1 A principal schematic diagram of a possible embodiment of a shock absorber 10 according to the present invention is shown. The shock absorber 10 is presented in a 2-tube configuration and includes a tubular shock absorber housing 12, an inner tube 18, and a damping valve element 14. The inner tube 18 is axially inserted into the damping element 14 in the lower region via a bottom valve element 16, wherein the bottom valve element 14 closes the inner tube 18 at the bottom and circumferentially seals it against the inner circumference of the tubular shock absorber housing 12. An intermediate space is formed between the tubular shock absorber housing 12 and the inserted inner tube 18 and is closed at the bottom via the bottom valve element 16. The inner tube 18 is filled with a damping medium, and a working piston 22 mounted on a piston rod 20 is guided in the inner tube 18 in an axially movable manner. The direction of movement of the working piston 22 can be defined as the longitudinal direction of the shock absorber 10. The upper end of the tubular shock absorber housing 12 is sealed by means of a piston rod guide (not shown).

[0021] During operation, a high-pressure working chamber 26 is formed within the inner tube 18, wherein the working piston 22 divides the chamber into a piston rod-side region 26a and a region 26b away from the piston rod. The high-pressure working region 26 extends through an opening 44 in the wall of the inner tube 18 to the intermediate space between the inner tube 18 and the tubular shock absorber housing 12. The high-pressure working chamber 26 is defined relative to the low-pressure working region 26, which is formed within the tubular shock absorber housing 12 during operation, by a bottom valve element 16. Furthermore, a gas volume 42 is provided within the tubular shock absorber housing 12, which is defined relative to the low-pressure working region 26 by a separating piston 40, which is axially movable within the tubular shock absorber housing 12.

[0022] The damping valve element 14 is mounted on the outside of the tubular shock absorber housing 12, and its function will be further described below in conjunction with the working movement of the working piston 22. The damping valve element 14 has an inlet opening 28 and an outlet opening 30, and is fluidly connected to the high-pressure chamber 26 through the inlet opening 28 and to the low-pressure chamber 24 through the outlet opening 30 via corresponding holes formed in the tubular shock absorber housing 12.

[0023] The damping valve element 14 in the illustrated embodiment includes: a controllable valve unit 34; a second valve unit 36 ​​having a defined flow cross-section, disposed downstream of the first controllable valve unit 34 along the flow direction of the damping medium; and a hydraulic intermediate chamber 38 disposed between the two valve units. The damping valve element 14 can be positioned between an open position and a closed position by means of the controllable valve unit 34.

[0024] Reference Figures 2 to 5 The circulation of the damping medium in the shock absorber 10 is described in the compression stage, the rebound stage, and when the damping valve element 14 is open and closed, respectively.

[0025] Figure 2 The damper 10 in the rebound phase is shown, indicated by arrow 46 in the piston rod region. Additionally, the damping valve element 14 or controllable valve unit 34 is in the closed position. As a result, the damper 10 provides a stiff characteristic during operation. The piston rod 20 and the working piston 22 move upwards in the direction of arrow 46. The damping medium flows from the region of the high-pressure chamber 26 on the piston rod side to the region on the distal side of the piston rod through valve element 48 in the working piston 22. The flow of the damping medium is indicated by arrow Q1. To compensate for the piston rod volume, the damping medium flows from the low-pressure chamber 24 to the high-pressure chamber 26 through check valve 50 in the bottom valve element 16. As a result, no damping force is generated. This flow of the damping medium is indicated by arrow Q. A express.

[0026] Figure 3The damper 10 in the rebound phase is also shown, indicated by arrow 46 in the piston rod region. Additionally, the damping valve element 14 or controllable valve unit 34 is in the open position. As a result, the damper 10 provides a soft characteristic during operation. The piston rod 20 and the working piston 22 move upwards in the direction of arrow 46. The damping medium flows through opening 44 from the high-pressure chamber 26 region on the piston rod side into the intermediate space between the inner tube 18 and the tubular damper housing 12, and enters the damping valve element 14 through the inlet opening. The damping medium exits the damping valve element 14 again through outlet 30 into the low-pressure chamber 24. The damping medium then continues to flow through the check valve 50 in the bottom valve element 16 into the region of the high-pressure chamber 26 away from the piston rod. The flow of the damping medium is indicated by arrow Q2. To compensate for the piston rod volume, the damping medium flows through valve element 48 in the working piston 22 from the high-pressure chamber 24 on the piston rod side into the high-pressure chamber 26 away from the piston rod. As a result, a small damping force is generated. This flow of the damping medium is indicated by arrow Q1. Within this operating range of the damper 10, the damping medium flows primarily through the damping valve element 14 (i.e., Q1 << Q2). The release piston 40 moves upward to compensate for the volume of the piston rod 20 extending from the tubular damper housing 12. The distribution between flows Q1 and Q2 can be altered by the valve unit 34 in an intermediate position between the open and closed positions, thereby enabling the setting of different damping characteristics during the rebound phase.

[0027] Figure 4 The damper 10 in the compression phase is shown, indicated by arrow 54 in the piston rod region. Additionally, the damping valve element 14 or controllable valve unit 34 is in the closed position. As a result, the damper 10 provides a stiff characteristic during operation. The piston rod 20 and the working piston 22 move downwards in the direction of arrow 46. The damping medium flows from the high-pressure chamber 26 to the low-pressure chamber 24 through valve element 52 in the bottom valve element 16. The flow of the damping medium is indicated by arrow Q3. Through valve element 54 in the working piston 22, the damping medium further flows in a small amount from the region of the high-pressure chamber 26 away from the piston rod into the region on the piston rod side. The flow of the damping medium is indicated by arrow Q*4. This flow of the damping medium can be used to generate damping force.

[0028] Figure 5Shows a shock absorber 10 in the compression phase, which is indicated by the arrow 54 in the piston rod region. Additionally, the damping valve element 14 or the controllable valve unit 34 is in the open position. As a result, the shock absorber 10 provides a soft characteristic during operation. The piston rod 20 and the working piston 22 move downward in the direction of the arrow 46. The damping medium flows from the region of the high-pressure chamber 26 remote from the piston rod into the region of the high-pressure chamber 26 on the piston rod side through the valve element 54, and then flows through the opening 44 into the intermediate space between the inner tube 18 and the tubular shock absorber housing 12, and through the inlet opening into the damping valve element 14. The damping medium leaves the damping valve element 14 again through the outlet opening 30 and enters the low-pressure chamber 24. The flow of the damping medium is indicated by the arrow Q2. A small portion of the damping medium flows directly from the high-pressure chamber 26 into the low-pressure chamber 24 through the valve element 52 in the bottom valve element 16, i.e., the flow Q3. In this operating range of the shock absorber 10, the damping medium mainly flows through the damping valve element 14, i.e., Q3 << Q4. The separating piston 40 moves downward in order to compensate for the volume of the piston rod 20 entering the tubular shock absorber housing 12. The distribution between the flows Q3 and Q4 can be changed by an intermediate position of the valve unit 34 between the open and closed positions, so that different damping characteristics can be set in the compression phase.

[0029] Figure 6 Shows a simplified embodiment of the damping valve element 14, in which only the controllable valve unit 34 is provided.

[0030] List of reference numerals

[0031] 10 Shock absorber

[0032] 12 Tubular shock absorber housing

[0033] 14 Damping valve element

[0034] 16 Bottom valve element

[0035] 18 Inner tube

[0036] 20 Piston rod

[0037] 22 Working piston

[0038] 24 Low-pressure chamber

[0039] 26 High-pressure chamber

[0040] 26a High-pressure region on the piston rod side

[0041] 26b High-pressure region remote from the piston rod

[0042] 28 Inlet opening

[0043] 30 Outlet opening

[0044] 32 valve elements

[0045] 34 controllable valve units

[0046] 36 Second Valve Unit

[0047] 38 hydraulic intermediate chamber

[0048] 40 Separating Piston

[0049] 42 gas volume

[0050] 44 openings

[0051] 46 rebound stage

[0052] 48 valve elements

[0053] 50 check valve

[0054] 52 valve components

[0055] 54 Compression Stage

Claims

1. A controllable shock absorber (10) having a damping force control system, said controllable shock absorber comprising: A tubular shock absorber housing (12) and a damping valve element (14) for controlling damping force, the tubular shock absorber housing being at least partially filled with a damping medium, the damping valve element being disposed on the tubular shock absorber housing (12) and fluidly connected to the tubular shock absorber housing. The inner tube (18) is inserted into the tubular shock absorber housing (12) via a bottom valve element (16). The piston rod (20) is capable of moving longitudinally within the inner tube (18) and has a working piston (22). in, The bottom valve element (16) divides the tubular shock absorber housing (12) into a low-pressure chamber (24) and a high-pressure chamber (26, 26a, 26b) acted upon by the working piston (22), and The separating piston (40) located in the tubular shock absorber housing (12) separates the damping medium in the low-pressure working chamber (24) from the gas volume (42) held in the tubular shock absorber housing (12). The inlet opening (28) of the damping valve element (14) is fluidly connected to the high-pressure chamber (26), and the outlet opening (30) of the damping valve element (14) is fluidly connected to the low-pressure chamber (24), so that the damping valve element (14) is connected in parallel with the working piston (22). During the rebound phase, the damping valve element (14) can be in the closed position, allowing the damping medium to flow through the working piston (22) and the bottom valve element (16) without flowing through the damping valve element (14). During the rebound phase, the damping valve element (14) can be in the open position, allowing the damping medium to flow through the working piston (22), the bottom valve element (16), and the damping valve element (14).

2. The controllable shock absorber (10) according to claim 1, characterized in that, The gas volume (42) is arranged inside the damping valve element (14) or in the tubular shock absorber housing (12).

3. The controllable shock absorber (10) according to claim 1, characterized in that, The inner tube (18) is inserted into the tubular shock absorber housing (12) through the bottom valve element (16), such that the bottom valve element (16) is inserted into the inner circumference of the tubular shock absorber housing (12) and forms a hydraulic seal with the inner tube (18).

4. The controllable shock absorber (10) according to claim 1 or 2, characterized in that, The damping valve element (14) can be continuously adjusted between any desired minimum damping characteristic and any desired maximum damping characteristic.

5. The controllable shock absorber (10) according to claim 3, characterized in that, The damping valve element (14) has at least one controllable valve unit (34), and the damping characteristics can be switched by means of the controllable valve unit.

6. The controllable shock absorber (10) according to claim 5, characterized in that, The controllable valve unit (34) includes a manually adjustable valve, an electrically adjustable valve, or an electromagnetically adjustable valve for switching the damping characteristics.

7. The controllable shock absorber (10) according to claim 5, characterized in that, A second valve unit (36) having a defined flow cross-section is connected upstream or downstream of the controllable valve unit (34) along the flow direction of the damping medium.

8. The controllable shock absorber (10) according to claim 7, characterized in that, A passive valve unit is also provided, which is connected in parallel or in series with the controllable valve unit (34) and / or the second valve unit (36).

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