JP3583361B2 - Vibration damper with adjustable damping force - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The invention relates to a vibration damper (vibration damper, shock absorber) with adjustable damping force according to the preamble of claim 1.
[0002]
[Prior art]
DE 197 23 347 A1 (DE 197 23 347 C1) describes elastic legs (suspension struts, shock absorbing struts) with load-dependent damping, in particular for motor vehicles (motor vehicles such as motor vehicles). , Federbein). The elastic leg surrounds a hydropneumatic vibration damper having a piston rod connected to a piston body (a vibration damper by the action of liquid and gas), and a member connected to a vehicle and a container of the vibration damper. A resilient means (suspension spring, Traggeder) disposed between the resilient means support (spring carrier), said piston rod being axially movably disposed in a piston rod guide, and a piston rod packing; The piston rod guide is a component of the damping valve. At that time, the change in the elastic force (elasticity) of the support elastic means is indirectly transmitted to the damping valve via the contact surface of the elastic means support with the member fixed to the container, thereby causing a load-dependent adjustment. . In this case, an auxiliary device is provided which is supported by the container or a member fixed to the container and exerts an additional elastic force on the supporting elastic means via the elastic means support.
[0003]
In the case of this structure, the elastic coefficient (spring constant, Federrate) of the vehicle supporting elastic means is immediately adjusted in addition to the damping force when the auxiliary device is adjusted. Damping force adjustment independent of the vehicle support elastic means is also possible. Such damping force adjustments are known, for example, from DE 199 16 39 A1 (DE199 01 639 A1). For this purpose, a cylindrical connection (Rohrstutzen) is formed on the surface (side surface) of the cylinder of the vibration damper, which is connected to an adjustable damping valve. This type of cylindrical connection requires a certain amount of manufacturing costs (manufacturing effort). This is because the tubular connection requires a small manufacturing tolerance.
[0004]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION It is an object of the invention to create an adjustable damping valve which allows the simplest possible connection to a vibration damper.
[0005]
[Means for Solving the Problems]
According to the invention, the object is to provide a sleeve-shaped support axially connected to a cylinder, the sleeve-shaped support having an axially adjustable (possibly axially displaceable) piston, The piston is also operatively connected to the damping valve on the other hand (Wirkverbindung, operatively connected, i.e. not only the two members are directly connected, but also for movement, i.e. via the other And the support includes a bottom, whereby the support and the bottom form a pressure chamber filled with a pressure medium, The problem is solved by the piston being guided movably in the axial direction in the pressure chamber. The sleeve-shaped support can be particularly easily fixed to the cylinder. Furthermore, it is possible to utilize an adjustable valveless vibration damper cylinder. The support may be a member independent of the cylinder that is disposed on the cylinder but is not flowed through by the working medium in the cylinder.
[0006]
In a first purely mechanical embodiment, the support has a threaded part that cooperates with an adjustable piston thread.
In another advantageous embodiment, the piston has a stop which limits the prestressing stroke (Vorspannweg) of the piston to the damping valve.
[0007]
In addition, the piston may have at least one tool surface for the adjustment movement (Werkzeugflaeche).
Instead, the support has a bottom, so that the support and the bottom form a pressure chamber filled with a pressure medium, in which the piston is guided movably in the axial direction. Is also good. The pressure chamber is in communication with a pressure source, which generates a pressure level depending, for example, on the load (load, Beladung) or on other parameters, such as the vehicle lateral acceleration (Fahrzeugquerbeschleunigung).
[0008]
In another embodiment, the support is configured to be movable in the axial direction and has a stop, which determines the end position in the removal direction of the support. This makes it possible to easily slide-mount the support as a structural unit on the cylinder of the vibration damper (push it in along the cylinder surface). For axial fixing, the support has locking means (catch means, Rastmittel), which form a locking connection (catch connection) with the stopper. The locking means need only be held in one direction, specifically in the removal direction. The operating pressure in the vibration damper results in that the locking means is always moved in the direction of the stop.
[0009]
It is possible for the support to be axially biased by additional elastic means and for the support to affect the prestress of the damping valve independently of the piston. Based on the axial mobility of the support, additional elastic means can influence the adjustable damping valve.
[0010]
It can be taken into account that the pressure in the pressure chamber loads the piston towards the adjustable damping valve. On the other hand, it is very significant if the piston is prestressed on one side by a failsafe-Feder towards the damping valve and defines a pressure chamber on the other side. At that time, the operating pressure in the pressure chamber acts against the force of the fail-safe elastic means. In the case of a lack of operating pressure (failure, Ausfall), the maximum prestress of the fail-safe elastic means appears at the damping valve.
[0011]
In order to simplify the use of the additional elastic means, the pressure connection for the pressure chamber may be made radially on the support. Thereby, a larger engagement surface at the bottom of the support is freed by the additional elastic means.
[0012]
In order to solve the possible tightness (sealing) problem as simply as possible, a flexible tube filled with a pressure medium and sealing the pressure chamber may be provided in the pressure chamber. .
[0013]
The solution in which the bottom of the support has two concentrically arranged guide ring lands (piston lands, Fuehrungsringstege), between which the piston is arranged, is particularly space-saving and The seal turned out to be simple.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described in detail based on the description of the following figures.
FIG. 1 shows the piston rod end of a vibration damper with an adjustable damping valve,
FIG. 2 shows an adjustable damping valve with a pressure tube in the pressure chamber;
FIG. 3 shows an adjustable damping valve with fail-safe resilient means,
FIG. 4 shows the support as a part,
FIG. 5 shows a cross-sectional view of FIG.
FIG. 6 shows a vibration damper with additional elastic means,
FIG. 7 shows a vibration damper with an adapter ring.
[0015]
FIG. 1 shows an end of the vibration damper (vibration damper) 1 on the piston rod side. The vibration damper has a piston rod 5 movable in the axial direction in a cylinder 3. A piston rod guide 7 defines a cylinder on the end side and thereby defines a working chamber 9. An adjustable damping valve 11 is arranged in the piston rod guide 7. The adjustable damping valve comprises a valve plate 13 and damping valve elastic means (damping valve spring) 15. A fluid communication part (liquid communication part) 17 to the compensation chamber 19 is formed in the piston rod guide part, and when the valve plate is lifted from the valve seat by the pressure in the working chamber filled with the damping medium. The fluid communication part is opened.
[0016]
The whole vibration damper 1 is sealed by the piston rod packing 21. The piston rod packing has a reinforcement (Armierung) and is supported on the valve plate 13 via a transmission sleeve (Uebertragungshuelse) 23.
[0017]
A sleeve-shaped support 25 having a bottom 27 is axially connected to the cylinder. The bottom part of the support, the sleeve part, and the ring land (ring strip part, piston land, Ringsteg) 29 cooperate with the piston 31 to form a pressure chamber 33. The pressure chamber is filled with a pressure medium, for example oil or air, and can be actuated via a pressure connection 35 at the operating pressure. The piston 31 is prestressed by the operating pressure in the pressure chamber in the direction towards the adjustable damping valve and is supported on the valve plate via a piston rod packing and a transmission sleeve, and is thereby regulated. Exerts a closing force on the possible damping valve. Packings are provided at the inner and outer diameters of the piston to combat the loss of pressure medium. Depending on the ratio of the closing force in the pressure chamber to the operating pressure in the working chamber 9, the damping medium can flow via the fluid communication to the compensation chamber 19. There is no flow communication between the working chamber and the whole support in the vibration damper.
[0018]
The support 25 has locking means 37. The locking means cooperate with the stop 39 of the vibration damper to form a locking connection. During assembly, the support itself, as a completed structural unit, is simply pushed into the vibration damper until the locking means resiliently rests behind the stop. In the removal direction, the support is axially fixed. However, in the direction toward the adjustable damping valve, the support can be further pressed against the vibration damper. The operating pressure in the pressure chamber causes the locking means to always abut the stopper. For that reason, another axial fixation for the support is not essential. In order not to apply too much load on the damping valve whose operating pressure is adjustable, the piston 31 has a stopper 41 which limits the piston stroke.
[0019]
The configuration shown in FIG. 2 broadly corresponds to the configuration of FIG. The difference is that instead of packing in the piston 31, a flexible tube 43 sealing the pressure chamber 33 is incorporated. At that time, the piston 31 may be configured as a simple plate element (a plate bending member, a member obtained by bending a plate).
[0020]
Another difference lies in the radially arranged pressure connection 35 for the pressure chamber 33. Thereby, the bottom 27 of the support 25 can be used as a stopper surface (collision surface) for the additional elastic means.
[0021]
FIG. 3 shows an adjustable damping valve with fail-safe resilient means (fail-safe spring, Failsafe-Feder) 47. The fail-safe elastic means 47 pushes a fastening sleeve 49 via the piston 31. On the other hand, the clamping sleeve acts on the valve plate 13 via the piston rod packing 21 and the transmission sleeve 23. Thereby, the piston 31 is prestressed on one side towards the damping valve adjustable by the fail-safe resilient means 47 and loaded on the other side by the pressure in the pressure chamber 33, or the piston is The pressure chamber is defined. The pressure in the pressure chamber acts against the elastic force (spring force) of the fail-safe elastic means. As a result, the maximum closing force acts on the valve plate in the event of a pressure loss (pressure failure, Druckausfall).
[0022]
FIG. 4 shows the support 25 in a configuration in which the piston is guided between two guide ring lands 29a; 29b, the guide ring lands defining a pressure chamber 33. As the piston, a tubular body provided with a simple O-ring 51 as a sealing means can be incorporated. In this illustration, the locking means 37 configured as radially elastic segments are recognizable.
[0023]
FIG. 5 shows a cross-section development (Schnittverlauf) specific to FIG. For reinforcement, the support, in particular the bottom 27, has reinforcing ribs 53 which extend radially. This rib is significant, for example, when the additional elastic means 55 is used as shown in FIG.
[0024]
The pressure connection 35 is arranged radially to the support but tangential to the pressure chamber 33. It is thus achieved that very narrow pressure chambers are possible independent of the diameter of the pressure connection.
[0025]
FIG. 6 shows the adjustable valve corresponding to FIG. 1 associated with the support shown in FIGS. 4 and 5. It is evident that the additional elastic means (auxiliary elastic means) 55 additionally or alternatively influences the damping action of the adjustable damping valve independent of the piston 31. To that end, the support 25 is axially movable and can transmit the movement of the additional elastic means to the valve plate 13.
[0026]
FIG. 7 includes two embodiments. In the cross section of the right half, a support 25 fixed to the vibration damper 1 in the axial direction is shown. The bottom 27 has two guide ring lands 29a; 29b and can move axially with respect to the support. The bent edge (flanged) edge 25 a prevents the bottom 27 from being pushed out of the support by the pressure in the pressure chamber 33. In order to seal the pressure chamber, the side of the piston 31 facing the pressure chamber is entirely covered by packing. The packing provides a sealing action at the inner and outer diameters of the piston. Also in the case of this modification, the additional elastic means 55 (see FIG. 6) can be used.
[0027]
In the left half section of FIG. 7, a mechanically adjustable (possibly repositionable) piston 31 is used together with a resilient device (spring device) 57. The resilient device 57 provides the necessary prestress on the valve plate 13. The adjustment stroke of the piston 31 causes a change in the prestress of the elastic device 57. The support has a threaded portion 59 which meshes with a screw 61 at the outer diameter of the piston. A locking ring (snap ring) 63 prevents the piston 31 from being pushed out of the support 25 or accidentally loosened and pulled out. At least one tool surface 65 is free due to the adjustment movement transmitted from the tool (not shown) to the piston.
[0028]
For both variants of FIG. 7, the vibration damper 1 has an adapter ring 67. The adapter ring 67 is welded to the vibration damper. In this case, a welding method without thermal deformation is advantageous. The adapter ring is already welded during the manufacture of the outer cylinder of the vibration damper. The adapter ring has a radially widened (hem-spreading) region 67a, which is also welded to the support 25 or joined using a fastening belt (Spannband) 69.
[0029]
As can be seen in the cross section of the left half, the vibration damper is provided with free space for the forming tool which wraps around the outer cylindrical part of the vibration damper or provides a lock bead. A minimum distance A from the upper edge must be maintained.
[Brief description of the drawings]
FIG. 1 shows a piston rod-side end of a vibration damper with an adjustable damping valve.
FIG. 2 shows an adjustable damping valve with a pressure tube in a pressure chamber.
FIG. 3 shows an adjustable damping valve with fail-safe resilient means.
FIG. 4 is a view showing a support as a component.
FIG. 5 is a diagram showing a sectional view of FIG. 4;
FIG. 6 is a diagram showing a vibration damper provided with an additional elastic means.
FIG. 7 is a diagram showing a vibration damper provided with an adapter ring.
[Explanation of symbols]
Reference Signs List 1 vibration damper 3 cylinder 11 damping valve 25 support 27 bottom 29a; 29b guide ring land 31 piston 33 pressure chamber 35 pressure connection 37 locking means 39 stopper 41 stopper 43 tube 47 fail-safe elastic means 55 additional elastic means 59 screw part 61 Screw 65 Tool surface 67 Adapter ring

Claims (9)

A cylinder having a piston rod disposed axially movably in the cylinder, the cylinder forming a working chamber, the working chamber having a damping valve on an end side, and the damping valve being A vibration damper with adjustable damping force, adjustable with respect to the throttle action of
A sleeve-shaped support (25) is axially connected to the cylinder (3), the support having an axially adjustable piston (31), while the piston is connected to the damping valve. Being in an operative connection, said support (25) having a bottom (27), whereby the support (25) and the bottom (27) form a pressure chamber (33) filled with a pressure medium. The piston (31) is movably guided in the axial direction in the pressure chamber. Vibration according to claim 1, characterized in that the piston (31) has a stopper (41), which limits the prestressing stroke of the piston (31) to the damping valve (11). Attenuator. Characterized in that said support (25) is configured to be axially movable and has locking means (37), said locking means determining a terminal position in the removal direction of said support (25), The vibration damper according to claim 1. The vibration damper according to claim 3, characterized in that the locking means (37) form a locking connection with the stopper (39) of the vibration damper. The said support (25) is axially biased by additional elastic means (55), and said support (25) influences said adjustable damping valve (11). 4. The vibration attenuator according to 3. The piston (31) is prestressed on one side by means of a fail-safe resilient means (47) towards the adjustable damping valve (11) and on the opposite side the pressure chamber (31). 33. The vibration damper according to claim 1, wherein the vibration damper defines (33). 2. The vibration damper according to claim 1, wherein the pressure connection for the pressure chamber is arranged radially on the support. 3. A flexible tube (43) is arranged in said pressure chamber (33), said flexible tube being filled with a pressure medium and sealing said pressure chamber (33). Item 4. The vibration damper according to Item 1. The bottom (27) of the support (25) has two guide ring lands (29a; 29b) arranged concentrically, between which the piston (31) is arranged. The vibration damper according to claim 1, wherein:

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