WO2018202386A1

WO2018202386A1 - Damping valve for a vibration damper

Info

Publication number: WO2018202386A1
Application number: PCT/EP2018/059085
Authority: WO
Inventors: Steffen Heyn; Michael Hegmann; Peter Wirth; Gerald Fenn; Wilhelm-Heinrich Broocks; Anton Krawczyk
Original assignee: Zf Friedrichshafen Ag
Priority date: 2017-05-05
Filing date: 2018-04-10
Publication date: 2018-11-08
Also published as: DE102017207605A1

Abstract

The invention relates to a damping valve for a vibration damper, comprising a damping valve body having at least one loading surface and having at least one valve seat surface for at least one valve disk lying on said surfaces, wherein the loading surface and the valve seat surface form a height profile because of the height position of the loading surface and of the valve seat surface with respect to a reference plane of the damping valve body, wherein the height profile, proceeding from the loading surface, has a negative slope with respect to the valve seat surface at least in a peripheral region of the loading surface.

Description

Damping valve for a vibration damper

The invention relates to a damping valve for a vibration damper according to the preamble of patent claim 1.

A fundamental peculiarity of a damping valve with a soft damping force characteristic is the tendency to bumps that are audible especially in modern vehicles inside the vehicle. From DE 34 45 684 A1 discloses a damping valve is known which has a central clamping surface for at least one valve disc and at least one bearing surface for this valve disc. Due to the level position of the bearing surface to the clamping surface, the opening and thus the noise behavior of the damping valve can be influenced.

In DE 197 35 249 C1 it is proposed to machine the support surface and the clamping surface in a process step to a defined final dimension in order to achieve optimum accuracy.

Despite the high production costs and the comparatively tight manufacturing tolerances, however, the Poltereffekt always occurs.

The object of the present invention is to provide a damping valve that is as free as possible from Poltereffekten even with a soft damping force characteristic.

The object is achieved in that the height profile has, starting from the clamping surface at least on a peripheral region of the clamping surface a negative slope to the valve seat surface.

When the valve disc is pressed onto the clamping surface in the mounted state of the damping valve, for example in the context of a tensioning chain of a piston rod pin or a valve rivet in the case of a bottom valve, then the damping valve body is slightly axially compressed in the region of the clamping surface. The compression is on the order of a few μ meters. The valve disc is located due to the residual stress, by a valve disc package or a valve spring also on the valve seat surface. Due to the height profile, the valve disc rolls on the valve seat surface. The roll-off function is generated by the negative slope. This prevents that the valve disc is hollow, ie a minimal gap between the valve disc and the valve seat surface occurs.

If the negative slope between the clamping surface and the valve seat surface is designed differently over the circumference of the clamping surface, then the positive effect of a targeted Abhubbewegung the valve disc of the valve seat surface occurs because the bias of the valve disc is defined over the circumference different. In the area of the lowest preload, the valve disc first lifts off the valve seat surface.

In a further advantageous embodiment, the clamping surface may have a negative slope in the direction of the valve seat surface. The advantage consists in a smoothed course of the bias within the valve disc.

Depending on the design of the damping valve, the valve seat surface may define an at least partially extending groove radially, so that a first valve seat surface is radially closer to the clamping surface than a second valve seat, wherein between the first valve seat surface and the second valve seat surface there is a difference in height, of a negative slope will be described starting from the first valve seat surface. This design is used when one wants to achieve a particularly large pressurized surface on the valve disc, which is greater than an exit area of a passage within the Dämpfventilkörpers. Due to the radial distance of the two valve seat surfaces could result in a hollow location within the valve seat surfaces, which in turn is prevented by the negative slope.

In this variant too, the first valve seat surface has a greater negative slope than the clamping surface in order to achieve a curved valve disk plane. In a further advantageous embodiment, the second valve seat surface has a greater negative slope than the first valve seat surface

In order to come as close as possible to a curved valve disk plane of higher order, a bridging plane between the clamping surface and the first valve seat surface has a greater negative slope than the clamping surface.

This is also the measure that the first valve seat surface has a greater negative slope than the bridging plane.

In addition, it can be provided that there is a positive gradient between the clamping surface and the valve seat surface relative to at least one circumferential region. About this measure can be set with a comparatively flat height profile a different bias over the circumference of the valve disc and achieve a targeted repeatable opening behavior of the valve disc.

In an alternative solution, starting from the clamping surface to the valve seat surface is a positive slope, which is dimensioned differently large over the circumference. For this purpose, the valve seat surface in relation to the clamping surface is simply made with a slight height excess and then partially reworked, z. B. ground. Then inevitably sets a positive increase, which causes the valve disc in an angular range has a higher bias voltage than in an adjacent angular range. Due to the different bias sets in the angular range with the lower bias the Abhubbewegung the valve disc of the valve seat surface.

In principle, there is the possibility that the plane of the valve seat surface and the plane of the clamping surface are inclined to each other. An inclination of the planes to each other is not necessarily linked to a plane plane of the valve seat surface (s) and the clamping surface.

The invention will be explained in more detail with reference to the following description of the figures. It shows:

Fig. 1 sectional view through a damping valve

FIG. 2 shows a top view of the damping valve body according to FIG. 1. FIG

3 is a sectional view of the Dämpfventilkörpers of FIG .. 1

FIG. 4 shows a further plan view of the damping valve body according to FIG. 1

5 perspective view of Fig. 2nd

6 Perspective view of FIG. 4

Fig. 7-12 schematic representations of the height profile of the damping valve

1 shows an example of a damping valve 1 for a vibration damper of any type. In principle, the invention could also be embodied on a bottom valve or an adjustable damping valve.

The damping valve 1 is designed on a piston rod 3, of which only one piston rod pin 5 is shown. In conjunction with FIGS. 2 to 6, it can be seen that a damping valve body 7 of the damping valve 1 has two separate groups of passage channels 9; 1 1, which extend substantially parallel to the central axis of the damping valve 1. The central axis of the damping valve 1 is congruent with the longitudinal axis of the piston rod 3 and the piston rod pin 5. The two groups of passage channels 9; 1 1 are flowed through in the opposite direction of a damping medium during operation of the damping valve. The damping medium passes through inlet openings 13; 15 in the passageways 9; 1 1, the outlet openings 17; 19 of at least one valve disc 21; 23 are covered. 1, a valve disc arrangement is shown by way of example. Many variations are conceivable. By means of a piston nut 25, the complete damping valve 1 is fixed to the piston rod 3.

As can be seen from the combination of FIGS. 1 to 6, the damper valve body has a central opening 27 for receiving the piston rod pin 5. On a first cover side of the damper valve body 7, hereinafter referred to as pull side 29, FIG. 2, is an annular clamping surface 31 z for at least one Venom tilscheibe 21 executed. An outer edge 33 of the clamping surface 31 z delimits a circumferential groove 35, which is closed radially on the outside by a closed meander-shaped valve seat surface 37 which is formed by a raised web 39 (FIG. 3). Within the channel 35, five passage channels 9a - 9c are arranged, exit the outlet openings 17 in the groove 35. The passage channels 9a - 9c are all located on a common pitch circle diameter and have a rectangular basic shape. Each outlet opening 17 of this group of passage channels 9a - 9 c has a plurality of funnel-shaped transitions 41 a - 41 c, which form the flow surface between the passage channels 9 a - 9 c and the channel bottom. At least one of the funnel-shaped transitions 41 a of each outlet opening is directed radially outward. Although the radial distance of the radially outer funnel edge 41a to the valve seat surface 37 is dimensionally equal at all outlet openings, the distance A1 of the valve seat surface 37 to the central axis in the region of an outlet opening 9a is different from the distance A2 of a valve seat surface or a valve seat surface region of a second outlet opening 9b executed to the central axis. It applies A1>A2> A3. The funnel angle of the transitions 41 varies slightly, since the passage channels 9a, 9b, 9c are arranged on a pitch circle. In addition, the passage channel 9 has at least one funnel-shaped transition 41 b; 41 c in the circumferential direction of the trough.

It has already been mentioned that the damping valve body 7 has five passageways 9a; 9b; 9c and thus has an odd number of passage channels. The distances A2; A2; A3 of the valve seat surface 37 with respect to an axis of symmetry 43 between the passage channel 9a and the center axis of the Dämpfventilkörpers 7 are executed in mirror image.

In the peripheral regions with the smallest groove width, the passage channels 1 1 are arranged for the other flow direction. These passageways 1 1 are designed as a slot, as shown in FIG. 2 can be seen, showing the inlet opening 15 of the passage channels 1 1. In FIGS. 4 and 6 it is clear that the outlet openings 19 of the passage channels have a greater width radially outward than radially inward and thus have a cloverleaf-like shape. The outlet openings 19 are framed by raised valve seat surfaces 45 which are mounted on a second cover page 47, in the further pressure side, are connected to an annular clamping surface 31 d. The valve seat surfaces 45 have in the region of the inlet openings 13 for the passage channels 9 of the opposite flow direction to a substantially parallel sealing edge. Furthermore, radially extending portions of the valve seat surface 45 define an inflow funnel 49 for the passageways 9.

FIG. 7 describes a cross section through the damping valve 1 using the example of FIGS. 4 and 6 with the inner clamping surface 31 and the radially positioned valve seat surface 45. Between these surfaces run the passage channels 9 which are enclosed by the valve seat surface 45. In Fig. 7 a horizontal reference plane 51 is located, the z. B. can be formed from the top side 47 of the Dämpfventilkörpers 7, from which the clamping surface 31 and the valve seat surface 45 extend axially. The clamping surface 31 and the valve seat surface 45 thus form a height profile on the damping valve body 7.

In the simplest embodiment of the invention, the height profile, starting from the clamping surface 31 at least on a peripheral region of the clamping surface 31 on a negative to the valve seat surface slope with the angle α. If one were to place the at least one valve disc 23 on the clamping surface 31 and not distort, then at least between the said peripheral region and the underside of the valve disc 23, a small air gap 53 before. The air gap would be very small in the order of between 0.001 and 0.005 mm. When the piston nut 25 is biased defined at the end of the valve assembly, then the Dämpfventilkörper 7 is slightly axially compressed and the air gap 53 is closed because the valve disc 23 is supported with a bias on the valve seat surface 45.

Again, in the simplest embodiment, the clamping surface 31 extends at right angles to the main axis, ie the central axis of the piston rod 3. In an expanded variant, the clamping surface 31 in the direction of the valve seat surface 45 has a negative slope.

In the left-hand half section of FIG. 7, the valve seat surface 45 is over-inflated compared to the right-hand half cut, ie, there is a positive gradient Consequently, there is then in this area a significant greater bias of the valve disc 23, since the valve disc 23 is more shielded during assembly of the piston nut 25 on the deeper clamping surface 31. The valve disk 23 will therefore lift off first from the valve seat surface 45 in the right half and then only in the region of the left half section. Simplified here are all valve seat 45 executed in a plane plan, which is inclined to the reference plane 51.

Figure 8 represents the simplest variant, as z. B. in Figures 2 and 5 can be applied. The valve seat surface 37 radially delimits the at least sectionally extending groove 35 so that a first valve seat surface 37i extends radially closer to the clamping surface 31 than a second valve seat surface 37a, wherein between the first valve seat surface 37i and the second valve seat surface 37a there is a height difference, that of a negative slope starting from the first valve seat surface 37i will be described. In FIG. 8, the negative slope, starting from the clamping surface 31, is constant over the first valve seat surface 37i to the second valve seat surface 37a. This embodiment represents a limit of the invention. Even with this construction, it is ensured that in the valve disc 21 in the mounted state, d. H. under tension there are no air gaps.

FIG. 9 shows a modification in which the pitch, starting from the clamping surface 31, is constant radially outward relative to a cutting plane, but can vary over the circumference. Thus, the negative slope in the right half section is greater than in the left half section, i. α 1> α 2. As a result, in the left half in the mounted state, a larger bias voltage within the valve disc 21 is established than in the right half section.

FIG. 10 is intended to illustrate an optimized height profile, in which the first valve seat surface 37 i has a greater negative gradient than the clamping surface 31. The second valve seat surface 37a in turn has a greater negative slope than the first valve seat surface 37i. A bridging plane 55 between the clamping surface 31 and the first valve seat surface 37 i has a greater negative slope than the clamping surface 31. However, the first valve seat surface 37i has a larger negative As a result, the tangents at the said planes form a curve corresponding to a higher-order mathematical function. In Fig. 10, the height profile over the entire circumference of the Dämpfventilkörpers is constant. Although the radial distances of the valve seat surfaces 37i, 37a can vary from one another, the envelope, represented by the valve disk 21 for the height profile, remains constant.

11, the envelope or the height profile is tilted, so that in turn the negative pitch between the clamping surface 31 and the valve seat surfaces 37i, 37a is designed differently over the circumference of the clamping surface. But also the slope within the clamping surface 31 is variable over the circumference.

FIG. 12 shows an alternative solution in which, starting from the clamping surface 31 to the valve seat surface 45, a positive gradient α 1; α 2 is present, which is dimensioned differently across the circumference. The plane of the valve seat surface 45 and the plane of the clamping surface 31 are inclined to each other. In the right half section, the valve seat surface 45 has a negative slope α 3 radially outward. The valve disc 23 has between the clamping surface 31 and the valve seat surface radially outward a positive slope α 1, ie the valve seat surface 45 is dimensioned raised to the clamping surface 31. In the left half section, the height profile, starting from the clamping surface 31, also extends with a positive pitch α 2 which is greater than in the right half section, ie the left area of the valve seat surface 45 is raised in relation to the clamping surface 31 and the valve seat surface 45 in the right half section. Again, the effect of different bias is utilized to promote a defined Abhubverhalten the valve disc.

REFERENCE CHARACTERS

I damping valve

3 piston rod

5 piston rod pins

7 damper valve body

9 passage channel

I I passageway

13 inflow openings

15 inflow openings

17 outlet openings

19 outlet openings

21 valve disc

23 valve disc

25 piston nut

27 central opening

29 train side

31 clamping surface

33 edge

35 gutter

37 valve seat surface

39 footbridge

41 funnel-shaped transition

43 symmetry axis

45 valve seat area

47 second cover page

49 inflow funnels

51 reference plane

53 air gap

55 Bridging level

Claims

claims

A damping valve (1) for a vibration damper comprising a damper valve body (7) with at least one clamping surface (31) and at least one valve seat surface (37; 45) for at least one valve disc (21; 23), wherein the clamping surface (31) and the valve seat surface (37; 45) form a height profile based on a reference plane (51) of the Dämpfventilkörpers (7), characterized in that the height profile starting from the clamping surface (31) at least has on a peripheral region of the clamping surface a valve seat surface (37, 45) negative slope.

2. Damping valve according to claim 1, characterized in that the negative slope between the clamping surface (31) and the valve seat surface (37, 45) over the circumference of the clamping surface (31) is designed differently.

3. Damping valve according to claim 1, characterized in that the clamping surface (31) in the direction of the valve seat surface (37, 45) has a negative slope.

4. damping valve according to claim 1, characterized in that the valve seat surface (37i, 37a) an at least partially extending groove (35) radially bounded, so that a first valve seat surface (37i) radially closer to the clamping surface (31) than a second valve seat surface ( 37a), wherein between the first valve seat surface (37i) and the second valve seat surface (37a) there is a height difference which is described by a negative slope from the first valve seat surface (37i).

5. Damping valve according to claim 4, characterized in that the first valve seat surface (37 i) has a greater negative slope than the clamping surface (31).

6. damping valve according to claim 4, characterized in that the second valve seat surface (37 a) has a greater negative slope than the first valve seat surface (37 i).

7. Damping valve according to claim 4, characterized in that a bridging plane (51) between the clamping surface (31) and the first valve seat surface (37i) has a greater negative slope than the clamping surface (31).

8. damping valve according to claim 7, characterized in that the first valve seat surface (37i) has a greater negative slope than the bridging plane (55).

9. Damping valve according to claim 1, characterized in that between the clamping surface (31) and the valve seat surface (37; 45) relative to at least one peripheral region is a positive slope.

10. Damping valve according to the preamble of claim 1, characterized in that starting from the clamping surface (31) to the valve seat surface (37; 45) there is a positive slope, which is dimensioned differently large over the circumference of the clamping surface.

11. Damping valve according to claim 10, characterized in that the plane of the valve seat surface (37; 45) and the plane of the clamping surface (31) are inclined to each other.