Vibration damper with adjustable damping valve devices

Abstract

Vibration damper comprising a working cylinder in which an axially movable piston rod with a piston separates a working chamber on the piston rod side from a working chamber remote from the piston rod, wherein the working cylinder is enclosed by a tubular body, wherein the tubular body and the working cylinder form annular fluid lines which are separated by an annular separating element, wherein each fluid line connects one of the two working chambers to an adjustable damping valve assembly, wherein the damping valve assemblies each have an inlet port and an outlet port and the two damping valve assemblies are connected on the outlet side to a common reservoir which compensates for the volume of damping medium displaced by the piston rod within the working cylinder, wherein the separating element has an annular groove.which is connected on the one hand to the outflow openings of the two adjustable damping valve devices and on the other hand to the common storage tank.

Description

[0001] The invention relates to a vibration damper with adjustable damping valve devices according to the preamble of claim 1.

[0002] In a vibration damper with one damping valve assembly per working direction located outside a working cylinder, the problem arises of fluid flow from one of the working chambers to the connected damping valve assembly. At first glance, this problem could be solved quite simply by attaching an adjustable damping valve assembly to the axially movable piston rod of the vibration damper and a second damping valve assembly to the bottom of a working chamber furthest from the piston rod, or even outside the working cylinder. However, this would result in the use of two different valve designs for the damping valve assembly. This level of complexity is often impractical.

[0003] DE 100 25 399 A1 discloses a vibration damper with two adjustable damping valve devices on an outer surface of an outer container tube. The vibration damper has a working cylinder with a working chamber on the piston rod side and a working chamber away from the piston rod. An axially two-part transmission tube forms a fluid connection between the working chamber on the piston rod side and a first adjustable damping valve device, and a second fluid connection between a working chamber away from the piston rod and a second adjustable damping valve device. An annular separating element is arranged between the two sections of the transmission tube, hydraulically isolating the two fluid connections.

[0004] The separating element has separate radial channels for the inlet and outlet of both adjustable damping valves. For proper function, the separating element must be aligned circumferentially with the two adjustable damping valves. Aligning the separating element is an assembly process that is difficult to automate.

[0005] US Patent 5,586,627 A discloses a vibration damper comprising two adjustable damping valve assemblies connected via a separating element to a reservoir within an outer tube body. The separating element forms a separate functional section within the axially divided outer tube body.

[0006] DE 10 2018 213 462 B4 features a separating element that limits a fluid connection to an external housing. A storage tank is located inside the external housing. Here, too, an axially divided outer tube body is used, with the separating element forming a longitudinal section of the outer tube body.

[0007] The object of the present invention is to simplify the fluid guidance in a vibration damper, thus solving the described assembly problem.

[0008] The problem is solved by the features of claim 1.

[0009] Thus, the flow paths in connection with the adjustable damping valve devices are very simple in design.

[0010] In a further advantageous embodiment, the separating element has a radial contact surface that rests on a cylindrical surface of the working cylinder. The working cylinder can be axially undivided. The outer tube body also does not require a parting line for the insertion of the separating element.

[0011] Preferably, the separating element is bonded to the working cylinder by a material-bonded connection. A fastening technique is preferred that causes at least minimal distortion to the working cylinder, e.g., soldering, gluing, or low-distortion welding processes such as laser welding.

[0012] Furthermore, it is provided that at least one axial end face of the separating element delimits one of the fluid lines to one of the adjustable damping valve devices. The separating element therefore does not need to have a nozzle geometry for the flow transition from the fluid line to the adjustable damping valve device. There is also no need for a rotational alignment of the separating element with respect to the adjustable damping valve device.

[0013] According to an advantageous dependent claim, the annular groove is bounded by ring flanges, each carrying at least one seal. The separating element can therefore be manufactured very easily using a primary forming process, for example, in a plastic injection molding process or a metal sintering process. The seals ensure that, for the sealing effect of the separating element, no double fit occurs with the radially adjacent components at the inner and outer diameters.

[0014] A further measure to simplify the flow paths within the vibration damper is to arrange the two adjustable damping valve assemblies axially offset from each other relative to the working cylinder. This eliminates any space constraints associated with the inlet openings of the adjustable damping valves and the annular groove for connection to the accumulator.

[0015] Preferably, the adjustable damping valve devices comprise an adjustable damping valve with only one flow direction, wherein a check valve is connected upstream of this damping valve, which is closed in this flow direction towards the damping valve device. The alternating flow through the damping valve device, but the one-way flow through the adjustable damping valve, is thus achieved independently of the design of the separating element.

[0016] The following description of the figures will be used to explain the invention in more detail.

[0017] It shows: Fig. 1 Longitudinal section through a vibration damper in the area of ​​the adjustable damping valve devices Fig. 2 Longitudinal section through the vibration damper according to Fig. 1 in the area of ​​an external storage device Fig. 3 Excerpt from the Fig. 1 in the area of ​​the separating element Fig. 4 Separating element as a single part Fig. 5 Detailed representation of the adjustable damping valve device according to Fig. 1

[0018] The Fig. 1 and Fig. Figure 2 shows a vibration damper 1 with a working cylinder 3 in which an axially movable piston rod 5 with a piston 7 separates a working chamber 9 on the piston rod side, completely filled with damping medium, from a working chamber 11 further away from the piston rod. The piston 7 can be designed as a closed displacer or optionally with a valve assembly known per se. The valve assembly can also act as a simple pressure relief valve between the two working chambers.

[0019] The working cylinder 3 is enclosed by a tubular body 13, wherein the tubular body 13 and the working cylinder 3 form annular fluid lines 15; 17. The piston rod-side working chamber 15 has at least one radial connection opening 19 into a first fluid line 15. The connection opening 19 can be located either in the wall of the working cylinder 3 or within a piston rod guide 21.

[0020] The working chamber 11, located away from the piston rod, also has at least one connection opening 23, which is preferably located in a support base 25 of the working cylinder 3. A radial connection opening in the wall of the working cylinder 3 is also possible.

[0021] An annular separating element 27 separates the two fluid lines 15; 17, each of which connects one of the two working chambers 9; 11 to an adjustable damping valve assembly 29; 31. The adjustable damping valve assembly 29; 31 comprises at least one adjustable damping valve 33 and one actuator 35. The exact design of the adjustable damping valve 33 and the actuator 35 is subordinate to the invention. Preferably, the adjustable damping valve 33 is designed as a main stage valve that experiences a hydraulic counterforce to an opening force caused by the excitation of the vibration damper via a pre-stage valve.

[0022] The pre-stage valve is preferably actuated by an electromagnetic actuator. Reference is made by way of example to DE 10 2021 202 304 A1, the entire content of which is to be considered part of this description.

[0023] The damping valve assemblies 29; 31 each have an inlet opening 37 and an outlet opening 39, the two damping valve assemblies 29; 31 being connected on the outlet side to a common reservoir 41, which compensates for the volume of damping medium displaced by the piston rod 5 within the working cylinder 3. The reservoir 41 is connected to the two adjustable damping valves 29; 31 outside the outer tube body 13 and comprises an inner pressure cylinder 43 containing a damping medium filling 45 and a compressed gas spring 49 separated by a separating piston 47. In this embodiment, the reservoir 41 is designed as a two-shell body, such that an annular space 53 exists between the inner pressure cylinder 43 and an outer housing 51, which serves as a hydraulic connection between the damping medium filling 45 and the working cylinder 3. Fig. 2) The use of the invention is not limited to this design of the storage device 41.

[0024] The two adjustable damping valve devices 29; 31 are arranged axially and also circumferentially offset from each other with respect to the working cylinder 3. Fig. 1) The outer pipe body 13 can optionally have two connections 55; 57 for a pump not shown, wherein the connections 55; 57 each open into one of the two fluid lines 15; 17.

[0025] The Fig. Figure 3 shows a section of the vibration damper 1 according to Fig. 1 in the area of ​​the separating element 27. The essential element of the separating element 27 consists in the fact that it has an annular groove 59 which is connected on one side to the outflow openings 39 of the two adjustable damping valve assemblies 29; 31 and on the other side to the common reservoir 41. For axial fixation and also for sealing, the separating element 27 has a radial contact surface 61, Fig. 4, which rests on an outer lateral surface of the working cylinder 3.

[0026] Preferably, the separating element 27 is materially bonded to the working cylinder 3 in order not to negatively affect the sliding surface for the piston 7 in the working chambers 9; 11. In principle, there is a relatively free choice of material for the separating element 27, although a primary forming manufacturing process is generally preferred.

[0027] The magnified view clearly shows that at least one axial end face 63; 65 of the separating element 27 axially limits one of the fluid lines 15; 17 to one of the adjustable damping valve assemblies 29; 31. The fluid lines 15; 17 into the adjustable damping valve assemblies 29; 31 are thus essentially defined by the working cylinder 3 and the outer pipe body 13. The outer pipe body may have a connection geometry, e.g., a pipe stub 67 for the transition to the adjustable damping valve 33.

[0028] In the Fig. Figure 4 shows the separating element 27 as a single component. The separating element 27 consists of a simple sleeve as its base body. The annular groove 59 is bounded by annular flanges 69 and 71, each of which carries at least one seal 77 and 79 in an annular groove 73 and 75. Thus, there are a total of three annular grooves 59, 73, and 75. No further radial or axial channels are necessary, making this component ideally suited for a primary mold manufacturing process.

[0029] When the piston rod-side working chamber 9 is compressed, the damping medium contained therein is displaced through the connection openings 19 into the first fluid line 15. The damping medium then reaches the adjustable damping valve assembly 29. During this flow process, the separating element 27 prevents the passage of damping medium into the second fluid line 17.

[0030] The damping medium then flows through the adjustable damping valve 33 within the adjustable damping valve assembly 29, which opens a more or less large flow cross-section. The damping medium then enters an annular space 81 within the adjustable damping valve assembly 29, which has the outflow opening to the annular groove 59. The adjustable damping valve 33 of the damping valve assembly 29 has only one flow direction, and a check valve 83 is located upstream of the adjustable damping valve 33 in the annular space 81, which is closed when the flow enters the damping valve assembly in this direction. Fig. 5)

[0031] The damping medium displaced from the piston rod-side working chamber 9 is replenished by damping medium from the reservoir 41 and can flow into the second adjustable damping valve assembly 31 via the annular groove 59 and the outlet opening 39, which then acts as an inlet opening. An identical check valve 83 in the second damping valve assembly 31 opens and, via the inlet opening 37, provides access to the second fluid line 17, which ensures a flow of damping medium into the expanding working chamber 11 located away from the piston rod.

[0032] During the retraction of the piston rod 5 into the working cylinder 3, the damping medium is displaced from the working chamber 11 furthest from the piston rod and through at least one connection opening 23 into the second fluid line 17. Even in this flow direction, the separating element 27 prevents a hydraulic short circuit between the working chambers 9 and 11 via the two fluid lines 15 and 17. The damping medium passes through the adjustable damping valve 33 of the damping valve assembly 31 and enters the annular groove 59 of the separating element 27 via the outlet opening 39. The majority of the damping medium can flow through the opening check valve 83 within the first adjustable damping valve assembly 29 into the first fluid line 15 and then further into the working chamber 9 on the piston rod side. The excess damping medium is displaced through the annular groove 59 in the separating element 27 into the connected reservoir 41. Reference sign 1 vibration damper 3 working cylinders 5 piston rod 7 pistons 9 piston rod-side working space 11 working space far from piston rod 13 pipe bodies 15 Fluid line 17 Fluid line 19 Connection opening 21 Piston rod guide 23 Connection opening 25 Support floor 27 Separating element 29 adjustable damping valve assembly 31 adjustable damping valve assembly 33 adjustable damping valve 35 Actuator 37 Inlet opening 39 Outlet 41 storage 43 pressure cylinders 45 Damping medium filling 47 separating pistons 49 Gas spring 51 cases 53 annular space 55 Connection for pump 57 Connection for pump 59 Ring groove in the separating element 61 Contact area 63 Front surface 65 Front surface 67 pipe fittings 69 Ring flange 71 Ring flange 73 Ring groove 75 Ring groove 77 Seal 79 Seal 81 Ring space 83 Check valve

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