WO2016083017A1

WO2016083017A1 - Damping valve

Info

Publication number: WO2016083017A1
Application number: PCT/EP2015/074082
Authority: WO
Inventors: Lothar Callies; Manuel Gumpert; Timo Schaffelhofer
Original assignee: Zf Friedrichshafen Ag
Priority date: 2014-11-25
Filing date: 2015-10-19
Publication date: 2016-06-02
Also published as: DE102014224021A1

Abstract

An adjustable damping valve (12) for a vibration damper (10), comprising a housing (14), on which a main valve (36) and an auxiliary valve (34) are arranged, wherein a valve body (37) of the main valve (36) is formed by a first valve element (28) and a second valve element (30), and the first valve element (28) and the second valve element (30) are each formed so as to be axially movable relative to the housing (14) and can lift off from a respective valve seat (30a, 34a) in order to influence a damping force of the damping valve (12), wherein the valve seat (34a) of the second valve element (30) is formed by the auxiliary valve (34), the second valve element (30) bears against the auxiliary valve (34), and the second valve element (30) can lift off from the auxiliary valve (34).

Description

damping valve

The invention relates to a damping valve according to the preamble of patent claim 1, and a vibration damper with such a damping valve.

A generic damping valve is shown in DE 198 22 448 A1. In this case, a main valve, which is formed by a valve body, and an additional valve connected in series and arranged axially to one another. The valve body in this case has two valve elements which are independent of each other and depending on the loading direction of the damping valve, i. Compression or Rebound, can lift off their respective valve seat to allow flow of damping medium through the damping valve and restrict this flow. The valve body is directly controlled in the direction of compression and piloted in the direction of rebound over a poppet. The additional valve ensures a basic damping in the direction of the compression and in the direction of the rebound of the damping valve. An assembly of the additional valve, which determines the damping force, is to be chosen as small as possible in the printing direction, with a minimum thickness of the assembly is determined by the acting loads to prevent strength problems. The minimum insertion of the additional valve in the pressure direction, and thus a minimum damping force can not be chosen completely free. Furthermore, such a damping valve builds relatively long in the axial direction.

It is therefore an object to provide an axially space-saving damping valve, wherein the damping valve and in particular the additional valve in the pressure direction to provide the lowest possible damping force.

This object is solved by the features of patent claim 1. In the dependent claims advantageous embodiments of the invention are described.

According to the invention, a generic damping valve is proposed in which the valve seat of the second valve element is formed by the additional valve, the second valve element rests against the auxiliary valve and the second valve element can stand out from the additional valve, in particular in the axial direction. As a result, an axial distance between the additional valve and the valve body of the main valve is reduced to a minimum, whereby the axial space of the damping valve is significantly shortened.

The basic structure of the damping valve may favorably correspond to the embodiments of DE 10 2010 001 302 A1 or DE 198 22 448 A1. The content of these two writings should therefore be regarded as the content of this document.

Conveniently, the damping valve is arranged via a housing on a piston rod and can accordingly move axially within a cylinder of a vibration damper. In this case, the damping valve, in particular its main valve and its additional valve, flows through a damping medium in a movement of the damping valve relative to the cylinder. The main valve and the additional valve are advantageously arranged in a valve housing which is conveniently fixed in the housing or is formed by the housing. The valve body of the main valve is formed by a first valve element, in particular a main slide, and a second valve element, in particular a control ring, which are formed axially movable relative to the valve housing and depending on the loading direction of the damping valve, ie in the printing direction or in the pulling direction , can lift off their respective valve seat. In this case, a valve seat of the first valve element is advantageously formed by the second valve element and a valve seat of the second valve element is formed by the additional valve. The additional valve can in this case form a plurality of valve seats for the second valve element. In addition, the first and / or the second valve element may also be designed in several parts. As a result, the axial space can be optimally utilized. In addition, the second valve element, the additional valve, in particular flow openings of the additional valve, directly control.

Advantageously, the main valve is directly controlled in the direction of the pressure stage and indirectly in the direction of the rebound stage, whereby a damping characteristic of the damping valve and its characteristic curve can be adapted to the requirements. The direct control of the pressure level, in particular by one of the valve elements, makes it possible to form the damping valve with very low damping force in the pressure direction. This is particularly advantageous if damping in the compression direction or even a damping force is to be generated mainly by a bottom valve of the vibration damper. In addition, the damping valve favorably has an actuator which can influence the main valve, in particular the valve body or its valve elements, in order to influence the damping force.

In an advantageous embodiment variant, the second valve element blocks flow openings of the additional valve when it rests against the valve seat. The flow openings serve the flow of damping medium through the additional valve.

Such flow openings can be opened, for example, by lifting the second valve element, if the damping medium to flow through the additional valve and optionally also the damping valve resistance possible. Such a resistance-free flow can thereby be made possible for one flow direction, for example in the pressure direction, and blocked in the other flow direction, for example in the pulling direction. For this purpose, the second valve element, for example, rest positively and / or non-positively on the valve seat of the additional valve. The one or more valve seats are expediently formed circumferentially around the respective flow openings or the respective flow openings. In an advantageous variant, the flow opening, in particular an edge of the flow opening on the surface of the additional valve, can itself form a valve seat. The second valve element can thereby release or block, in particular control, throughflow openings of the additional valve.

It is further proposed that the second valve element blocks flow openings formed as pressure openings, wherein the pressure openings serve the flow of damping medium in the pressure direction through the additional valve.

As a result, a low damping force in the pressure direction can be generated by the damping valve. In this case, the damping medium flows through the additional valve in the ideal case almost without resistance, in particular by the pressure openings, wherein the damping force preferably by the second valve element and the associated valve seat is determined. As a result, for example, acting as a damping agent disk packages can be avoided, which may be affected by low damping forces of strength problems.

In this case, a movement of the damping valve in the direction of pressure normally corresponds to a retraction movement of the damping valve into the cylinder of the vibration damper, a movement of the damping valve in the pulling direction corresponding to an extension movement of the damping valve out of the cylinder.

Preferably, the second valve element is formed in cross-section at least by two radially spaced valve webs and a connecting web or U-shaped.

The two valve webs of the second valve element in this case rest against the valve seats of the additional valve, wherein these are connected to one another on the side facing away from the additional valve by the connecting web, that the pressure openings can be blocked by the second valve element. In this case, the valve webs preferably extend in the axial direction, the connecting web advantageously in the axial direction. The second valve element may thus be U-shaped in cross section. Advantageously, the second valve element is closed in the circumferential direction or circular. In this case, one of the valve webs is advantageously arranged radially outside and one of the valve webs is arranged radially inside the through-openings to be blocked at the valve seats of the additional valve. A surface which is formed between the valve webs, the flow openings on the surface of the additional valve advantageously covers completely. At least one of the valve webs may also extend beyond the connecting web in the axial direction. The second valve element may therefore have a chair shape in cross-section. At such an end of the extended valve web, which deflects the additional valve, the second valve element can, for example, form a valve seat for the first valve element. Conveniently, a damping means is formed on the additional valve, which applies a damping force under load of the damping valve in the pulling direction. The damping agent preferably applies the steam force exclusively in the pulling direction.

The additional valve can thus generate a Grunddämpf force in the pulling direction, wherein a damping force in the pressure direction, for example, by the main valve and / or by an optionally formed on the vibration damper bottom valve can be generated. A damping force of the damping valve in the pressure direction can thereby be made very small. By reducing the required damping means can also reduce the number of components of the damping valve.

Furthermore, the flow openings can be formed on the additional valve as at least one pressure opening and at least one pulling opening, wherein the damping means throttles a flow of damping medium through the pulling openings.

The pressure opening is flowed through by the damping medium under load of the damping valve in the pressure direction, whereas the pulling opening is flowed through by the damping medium under load of the damping valve in the pulling direction. In this case, the above-described damping means is favorably arranged on the pulling opening, which generates the damping force in the pulling direction and expediently locks the pull opening under load in the pressure direction. In addition, the second valve element is favorably arranged at the pressure openings, which can block and release the pressure openings.

It is further proposed that the damping medium flows in a lifting of the second valve element of the valve seat of the additional valve substantially without resistance through the damping valve, in particular through the pressure openings of the additional valve. In addition, it may also be the case that the damping medium flows substantially without resistance through the damping valve.

In this case, the second valve element can lift off the additional valve to the

Release pressure opening. By the additional valve in this case no or only a negligible damping force is generated. The printing openings, in particular their Flow cross-sections, are favorably this very large or much larger than the train openings formed. A flow through the damping medium in the pressure direction through the additional valve can be carried out substantially without resistance. A damping force in the pressure direction is thus, as already mentioned, generated by the interaction of the second valve element and the corresponding valve seat on the additional valve, wherein this damping force can be very low, in particular lower than in a durable, designed as a disk package damping means.

Conveniently, the damping valve is used in a vibration damper, which has a bottom valve, which generates a damping force under load of the pressure stage.

The damping means is conveniently designed as a disk package.

It is also further proposed that the pressure openings are arranged on the additional valve on a larger circle and the Zugöffnungen on a smaller pitch circle.

As a result, a simple equipping the additional valve with a damping means and a simple control of the pressure openings through the second valve element is possible. In this case, the pressure openings are arranged substantially radially outside the pull openings. In addition, flow openings of the larger pitch circle, in particular their flow cross-section, can be made very large. In this case, a disk pack can be attached as a damping means at a midpoint of the additional valve and thereby cover the train openings starting from the center in the radial direction to the outside. If, in addition, the pressure openings are arranged essentially on a uniform pitch circle or radius on the additional valve, then the second valve element can be formed by a simple shape, for example by the U-shape or chair shape mentioned above. However, it may also be advantageous if the pressure openings on the small pitch circle, ie radially inward, and the pulling openings on the additional valve on the large pitch circle, ie radially outward, are arranged. It is also proposed a vibration damper having a damper valve according to one of claims 1 to 9 or according to at least one of the previous embodiments.

The vibration damper according to the invention and the associated damping valve are explained below by way of example with reference to the accompanying figures. The figures show:

1 shows a vibration damper with a damping valve, which comprises a main valve and an additional valve.

FIG. 2 shows the additional valve of FIG. 1 in an axial view; FIG.

Fig. 3 shows a further embodiment of the additional valve. FIG. 1 shows a vibration damper 10 with a damping valve 12. The damping valve 12 is operatively connected via a housing 14 with a piston rod 16. On the housing 14, a piston 1 8 is also arranged, which divides an interior of a cylinder 20 in an upper working space 22 and a lower working space 24. In the housing 14, a valve housing 26 is further arranged. In this case, in particular within the valve housing 26, a main valve 36 and an additional valve 34 is arranged. A valve body 37 of the main valve 36 is formed by a first valve element 28 and a second valve element 30. The valve elements 28, 30 can in principle also be designed in several parts. The two valve elements 28, 30 are axially adjacent to each other and each axially displaceable relative to the valve housing 26, wherein the second valve element 30 abuts the auxiliary valve 34 and can lift off axially thereof. The first valve element 28 is also referred to as the main slide 28, the second valve element 30 as the control ring 30. In this case, the first valve element 28 and the second valve element 30 are biased axially by a spring element 32 relative to the additional valve 34, whereby the prestressing can thus also be influenced by an actuator 40 via a damper characteristic curve of the main valve. The actuator includes, among other things, a coil and an armature. The main valve 36 and its operation are substantially already known from DE 198 22 448 A1. In addition, in the first valve element 28 a Check valve 38 is formed. This is already disclosed, for example, in DE 10 2010 001 302 A1. These two writings are therefore to be regarded as the content of this document.

The additional valve is shown inter alia in Figure 1 and in Figure 2. In this case, the additional valve 34 has pressure openings 42 and pull openings 44. The pressure openings 42 in this case serve a flow of damping medium from a lower working space 24 into an upper working space 22, that is to say when the damping valve 12 is loaded in the pressure direction. Accordingly, the pulling openings 44 serve a flow of damping medium from the upper working chamber 22 into a lower working space 24, that is to say when the damping valve 12 is loaded in the pulling direction.

In this case, a disc pack 46 is arranged as a damping means 46 on the additional valve 34, which is assigned to the pulling openings 44 and locks them in the pressure direction and releases in the pulling direction and generates a damping force in the pulling direction. Further, the pressure openings 42, the second valve element 30 is assigned, which blocks the pressure openings 42 in the pulling direction and can release in the pressure direction, depending on the load condition of the damping valve 12. The second valve member 30 encloses the pressure ports 42 to the additional valve 34 and locks them, especially as long the second valve element rests against the additional valve 34. Furthermore, the second valve element is biased by the spring element 32 relative to the additional valve 30, wherein this bias can be influenced by the actuator.

The second valve element 30 is in this case formed in cross-section by two valve webs 30b and a connecting web 30c. The valve webs 30b in this case have substantially in the axial direction and are connected to one another via the connecting web 30c, which extends substantially in the radial direction. The radially inwardly arranged valve web is in this case extended in the axial direction beyond the connecting web 30c and forms a valve seat 30a for the first valve element. The second valve element 30 is therefore formed in the cross-section substantially chair-shaped and has at least one U-shaped portion. In addition, the second valve element 30 is closed in the circumferential direction or circular. The connecting web 30c and the valve webs 30b in this case enclose the pressure openings 42 axially on one side on the additional valve 30. The valve webs 30b are arranged on corresponding valve seats 34a of the additional valve 34. Here, the valve seats 34 a are formed on a surface of the auxiliary valve 34. In principle, the edge at the corresponding flow openings 42, 44 serve as a valve seat.

3 shows a further arrangement of the second valve element 30 on the additional valve 34. In this case, a planar surface 34b is formed on the additional valve 34, which is formed radially outward on the additional valve 34 and is offset by one step relative to the remaining surface. This flat surface 34b is made with low tolerances or high accuracy, in order to ensure optimal installation of the second valve element 30 to the additional valve 34 and to prevent leakage. In this case, the valve webs 30b, in particular their contact surfaces 30d assigned to the plane surface 34b can likewise be produced with a low tolerance or high accuracy. This can be ensured, for example, by a single grinding operation in which both contact surfaces 30d of the second valve element 30 are processed simultaneously.

It can be seen in FIGS. 1 and 2 that the pressure openings 42 are arranged radially outward on a large pitch circle and the tension openings 44 are arranged radially inward on a small pitch circle. In this case, the pressure openings 42 and the pull openings 44 are each arranged substantially at a constant or uniform radius at the additional valve 34. The second valve element 30 may therefore be circular and thus complete all pressure ports in a simple manner. In addition, the damping means 46 may be formed as a simple circular disk package 46.

In addition, it can be seen in FIG. 2 that the pressure openings 42 are in this case designed in the circumferential direction as elongated holes with a large flow cross-section. As a result, a possible resistance-free flow of the

Damping medium through the additional valve 34 possible. The damping effect of the damping Valve 12 is thus determined mainly by the second valve element 30 and its associated valve seats 34a.

In principle, constant openings 48 are formed on the first valve element 28, on the second valve element 30 and / or on the additional valve 34. The constant openings need not be formed on all said elements, as long as minimum flow of damping medium through the damping valve 12 between the lower working chamber 24 and the upper working chamber 22 is possible. Here, the constant openings 48 are formed on the first valve element 28 and on the additional valve 34. At the additional valve 34, the laminated core is in its radially outer region of circumferential circumferential webs 62, wherein at these webs 62, the constant openings 48 are recessed.

The additional valve may be caulked, pressed or screwed, inter alia, on the piston 18.

In the following, the operation of the damping valve will be explained in more detail. During a movement of the damping valve 12 in the cylinder 20 in the pressure direction, ie from the piston rod 1 6 in the direction of additional valve 34, first flows a damping medium from the lower working chamber 24 through the constant openings 48 on the additional valve 34 and / or on the second valve element 30 in one Anteroom 50 of the damping valve. Furthermore, the damping medium flows from the vestibule 50 via the constant opening 48 of the first valve element 28 in the upper working chamber 22 on. The damping medium can also flow via the check valve 60 in a control chamber 54, via a throttle opening 52 in the upper working space, depending on the bias of the check valve 60. Increases a speed of movement of the damping valve 12, so a pressure on the surface 30e of the second valve element 30 on. The second valve element 30 can now lift off with sufficient force on the surface 30 e of the valve seats 34 a of the additional valve 34, whereby the damping medium from the lower working chamber 24 through the pressure ports 42 can flow directly into the upper working chamber 22. In this case, the damping effect is determined in the pressure direction by the second valve element 30 and its associated valve seats 34a, wherein the flow through the pressure port 42 itself is essentially without resistance. In this case, a flow of damping medium through the pulling openings 44 does not take place, apart from the constant openings 48, which are essentially negligible. The damping means 46 also generates no damping force at flow of

Damping medium in the pressure direction through the damping valve 12th

During a movement of the damping valve 12 in the pulling direction, ie of the additional valve 34 in the direction of the piston rod 1 6, the damping medium can first flow from the upper working chamber 22 via the constant openings 48 in the vestibule and then in the lower working space 24. Increases the speed of movement of the damping valve 12, so increases a pressure in the control chamber 54 through the throttle opening 52. From a certain pressure in the control chamber 54, the valve cone 56 lifts from its valve seat 58 on the first valve member 30 from. As a result, the damping medium can flow past the valve cone 56 via the antechamber 50 and the pull openings 44 and the damping means 46, in particular the disk package 46, into the lower working space 24. If the movement speed of the damping valve 12 increases further, the first valve element 28 can lift off its valve seat 30a due to the force of the pressure acting on the surface 28a and move axially relative to the bias by the spring 32. The damping medium can flow from the upper working space 22 past between the first valve element 28 and second valve element 30, in particular its valve seat 30a, into the antechamber 50 through the pulling openings 44 past the damping means 46 into the lower working space 24.

The second valve element 30 in this case permanently blocks the pressure openings, as a result of which the damping medium is damped by the damping means 46. The damping means 46 permanently generates a damping force at a flow of damping medium in the pulling direction. In addition, the check valve 60 remains closed under load of the damping valve 12 in the pulling direction. REFERENCE CHARACTERS

vibration

damping valve

casing

piston rod

piston

cylinder

upper working space

lower workspace

valve housing

first valve element, main valve second valve element, control ring valve seat

b valve bridge

c connecting bridge

d contact area

e area

spring element

additional valve

a valve seat

b plane surface

main valve

valve body

check valve

actuator

pressure opening

draft opening

Disk package, steaming agent

constant opening

anteroom

throttle opening

control room

shuttle valve seat

Check valve footbridge

Claims

claims

1 . An adjustable damper valve (12) for a vibration damper (10) comprising

- A housing (14) on which a main valve (36) and an additional valve (34) are arranged,

- Wherein a valve body (37) of the main valve (36) by a first valve element (28) and a second valve element (30) are formed, and

- The first valve element (28) and the second valve element (30) are each formed axially movable relative to the housing (14) and can be lifted from a respective valve seat (30 a, 34 a) to influence a damping force of the damping valve (12),

characterized in that the valve seat (34a) of the second valve element (30) is formed by the additional valve (34), the second valve element (30) abuts the auxiliary valve (34) and the second valve element (30) of the additional valve (34) can take off.

2. Adjustable damping valve (12) according to claim 1, characterized in that the second valve element (30) when applied to the valve seat (34 a) flow openings (42, 44) of the additional valve (34) blocks.

3. Adjustable damping valve (12) according to claim 2, characterized in that the second valve element (30) as pressure openings (42) formed flow openings (42, 44) blocks, wherein the pressure openings (42) the flow of damping medium in the pressure direction through the additional valve (34) serve.

4. Adjustable damping valve (12) according to one of claims 1 to 3, characterized in that the second valve element (30) in cross-section at least by two radially spaced valve webs (30b) and a connecting web (30c) or U-shaped.

5. Adjustable damper valve (12) according to one of claims 1 to 4, characterized in that on the additional valve (30) a damping means (46) is formed, which applies a damping force under load of the damping valve (12) in the pulling direction.

6. Adjustable damping valve (12) according to one of claims 2 to 5, characterized in that the flow openings (42, 44) on the additional valve (34) as at least one pressure opening (42) and at least one pull opening (44) are formed the damping means (46) throttles a flow of damping medium through the pulling openings (44).

7. Adjustable damping valve (12) according to one of claims 1 to 6, characterized in that the damping medium in a lifting of the second valve element (30) of the valve seat (34 a) of the additional valve (34) substantially without resistance through the additional valve (34). flows.

8. Adjustable damping valve (12) according to one of claims 5 to 7, characterized in that the damping means (46) by a disc package (46) is formed.

9. Adjustable damping valve (12) according to one of claims 3 to 8, characterized in that the pressure openings (42) on the additional valve (34) on a larger pitch circle and the pulling openings (44) are arranged on a smaller pitch circle.

10. Vibration damper (10) having an adjustable damping valve (12) according to one of the preceding claims.