DE102021201421B4 - Damping valve device for a vibration damper - Google Patents

Abstract

Damping valve device (1) with a throttle point (37) for a vibration damper (3), comprising a valve carrier (29) with an annular groove (33) in which a valve element (35) with a variable diameter is arranged, the valve element (35) having a flow guide surface (39) forms the throttle point (37), the cross section of which reduces with increasing flow speed of a damping medium within the throttle point (37), the annular groove (33) having a lateral surface (67) of the valve element (35) and annular groove side surfaces (57; 59) of the valve carrier (29) form a pressure chamber (63) which is connected to a working chamber (13) of the vibration damper (3) via an inflow opening (65) and an outflow opening (67), with the annular groove side surface (59) and a Cover side (69) of the valve element (35) an outflow cross section of the outflow opening (67) is limited, the size of which is determined by the radial expansion of the valve element (35) relative to the valve carrier (29), d acharacterized in that the outflow cross section of the outflow opening (67) has a maximum in an initial position of the valve element (35) in conjunction with a maximum cross section (45) of the throttle point (37), in that the cover side (69) of the valve element (29) is on a outer surface area (75) has a rib structure (71) and the annular groove side surface (59) of the valve carrier (29) facing the top side (69) has a groove (83) extending in the circumferential direction, which at least partially define the outflow cross section of the outflow opening (67).

Description

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

From the DE 10 2016 210 790 A1 a damping valve device is known in which a radially expandable valve element with a flow guide surface forms a throttle point that generates a higher damping force with increasing flow speed by reducing the size of a throttle cross section and thus following a progressive damping force characteristic.

The valve element is chambered in an annular groove and is prestressed radially inwards by an elastic limiting ring. The valve element can have a radial slit in order to reduce the forces necessary for an expansion movement.

With a throttle of this design, there is the fundamental problem that the progression of the damping force characteristic is very pronounced. As soon as a limit flow rate of the damping medium is exceeded within the throttle point, the damping force suddenly increases sharply. This operating behavior can be desirable for some applications, but represents a disadvantage for other applications.

The older one DE 10 2019 215 559 A1 discloses a damping valve device with a slotted valve element, the slot as the outflow cross section from a pressure chamber having a minimum outflow cross section in the maximum open position and also a maximum outflow cross section in the maximum throttle position, i.e. when the valve element has widened to the maximum, since the slot also increases in size .

The older one too DE 10 2019 215 556 A1 describes a damping valve device with a valve element which has a profiled top side in the direction of a groove side wall of a valve carrier. The profile serves to form a positive connection with the valve carrier in order to determine an expanded position of the valve element.

The older one DE 10 2019 212 966 A1 shows in the execution 4 a damping valve device with several outflow openings on different pitch circle diameters. With increasing expansion movement of the valve element in the direction of a flow guide surface, the effective outflow cross section increases from a minimum to a maximum.

The object of the present invention is to minimize the disadvantage known from the prior art.

The object is solved by the features of patent claim 1

This achieves pressure control that is dependent on the adjustment path of the valve element. The effect is exploited that, with a large outflow cross section, there is a delayed change in the diameter of the valve element and, in the case of a smaller outflow cross section, there is a more direct reaction of the valve element.

This starts a slow closing movement of the valve element, which leads to a later progression of the damping force in the damping force characteristic.

The rib structure ensures that the outflow channels are always open, which influences the outflow cross-section. Furthermore, a guide edge can be designed on one side of the ring groove with a view to minimizing friction between the valve element and the valve carrier, which edge cannot engage in the profile of the cover side.

With a radially inwardly closed profile of the top side, the outflow cross section of the outflow opening can be reduced with the simplest of means.

In the case of a standardized valve element, the rib structure of at least one additional ring element can be very easily adapted to a desired damping force characteristic of the damping valve device.

A further measure for dimensioning the outflow cross section of the outflow opening consists in the annular groove side surface of the valve carrier facing the top side having a groove extending in the circumferential direction.

Also in the configuration of the groove in the valve carrier, there is the possibility that the groove of the annular groove side surface is formed by an additional disk.

The additional disc is preferably supported on an outer edge of the valve carrier. If there is slight abrasion of the material when the additional disc is fastened to the valve carrier with a non-positive or positive fit, this can be very easily removed on its outer edge.

With regard to a smooth transition between the maximum open and the minimum outflow cross-section of the outflow opening has the Nut in the Ringnutseitenfläche on a different width over the circumference.

• 1 Schnittdarstellung durch einen Schwingungsdämpfer im Bereich der Dämpfventileinrichtung
• 2 Detaildarstellung der Dämpfventileinrichtung nach 1
• 3 Detaildarstellung vom Ventilträger
• 4 Alternativvariante zur Ausführung nach 2

The invention is to be explained in more detail on the basis of the following description of the figures.
It shows:

• 1 Sectional view through a vibration damper in the area of the damping valve device
• 2 Detailed view of the damping valve device 1
• 3 Detailed view of the valve carrier
• 4 Alternative variant to the version according to 2

The 1 shows a damping valve device 1 for a vibration damper 3 of any type of construction, which is only partially shown. In addition to the damping valve device 1 , the vibration damper 3 includes a first damping valve 5 with a damping valve body designed as a piston 7 which is fastened to a piston rod 9 .

The damping valve body 7 divides a cylinder 11 of the vibration damper into a working chamber 13 on the piston rod side and a working chamber 13 remote from the piston rod; 15, both of which are filled with damping medium. In the damping valve body 7 are passageways 17; 19 are designed for one flow direction on different pitch circles. The design of the passage channels 17; 19 is only to be regarded as an example. An exit side of the passage channels 17; 19 is provided with at least one valve disc 21; 23 at least partially covered.

In addition, the vibration damper has a cable stop 25, which comes into contact with a stop surface on the cylinder side, e.g. a piston rod guide 27, after a defined extension movement of the piston rod 9.

The cable stop 25 includes a valve carrier 29 which is fixed directly to the piston rod by a positive connection. A ring-shaped elastomer element 31 is placed on an upper side of the carrier 29, for example, which is held by a slight radial prestress even during an oscillating movement of the piston rod 9. The elastomer element 31 acts as an additional support spring from the stop point on the stop surface.

The valve carrier 29 has a circumferential annular groove 33, in which a variable-diameter valve element 35 is guided. This valve element 35 is radially movable or radially elastic and forms a valve body for a throttle point 37 as part of the damping valve device 1. The valve element 35 forms the throttle point 37 with an inner wall of the cylinder 11, the inner wall 39 representing a flow guide surface. In principle, the invention can also be implemented in a valve carrier that is independent of the cable stop.

On the outside, the valve element 35 carries a return spring 41, e.g. B. in the execution of a locking ring. Between the inner wall 39 and an outer lateral surface 43 of the valve element 35 there is a variable throttle cross section 45 which generates an additional damping force.

At a piston rod speed in a first operating range, e.g. B. less than 1 m / s, the throttle point 37 is fully open. The damping force is then only from the passage channels 17; 19 in connection with the valve discs 21; 23 generated. With an inflow of the valve disks 21; 23 raise the valve discs 21; 23 from its valve seat surface 47; 49 off. The lifting movement is carried out by a supporting disc 51; 53 limited.

In a second operating range with a piston rod speed that is greater than the limit speed of the first operating range, i.e. greater than the 1 m/s specified as an example, the valve element 35 changes to a throttle position and performs a closing movement in the direction of the flow guide surface 39. Due to the high flow speed of the damping medium in the throttle point 37 formed as an annular gap, a negative pressure is formed, which leads to a radial expansion of the valve element 35 . However, so that the throttle point 37 cannot become blocked under any circumstances, the return spring 41 maintains the defined minimum passage cross section.

The 2 shows an enlargement of the damping valve device 1 with a different attachment technique on the piston rod 9. In the enlargement it can be seen that the annular groove 33 with an inner lateral surface 55 of the valve element 35 and annular groove side surfaces 57; 59 and an annular groove base 61 forms a pressure chamber 63 which is connected to the working chamber 13 of the vibration damper 3 via an inflow opening 65 and an outflow opening 67 . The pressure chamber 63 causes a force component which is directed radially outward and widens the valve element 35 and which supports the negative pressure situation prevailing in the throttle point 37 .

The pressure chamber 63 has an outflow opening 67 so that a pressure level built up in the pressure chamber 63 can also relax again and so that the damping valve device 1 can be converted back into a maximum throttle cross section Axial opening formed in the valve carrier 29, but by the annular groove side surface 59 of the valve carrier 29 and a cover side 69 of the valve element 35.

However, the cross section of the outflow opening 67 is not constant, but its size is determined by the radial extent of the valve element 35 relative to the valve carrier 29 .

It has turned out to be advantageous with regard to the comfort behavior of a vehicle if the outflow cross section has a maximum in an initial position of the valve element in conjunction with a maximum cross section of the throttle point 37 . If the throttle point 37 is opened to the maximum, i.e. generates the minimum damping force, then the valve element 35 should only move a closing movement in the direction of the flow guide surface 39, i.e. the inner wall of the cylinder 11, after a certain pressure build-up in the pressure chamber 63. The pressure build-up is achieved by the large outflow cross-section.

The inner lateral surface 55 of the valve element 35 is inclined in the direction of the pressure chamber 35 . When pressure is applied, the inclined lateral surface 55 provides a vertical force component that displaces the valve element 35 in the direction of the annular groove side surface 59 that is opposite the inflow opening 65 . Consequently, at the beginning of the pressure build-up, a discharge cross-section with a greater height is available than in the case of an advanced pressure build-up when a top side 69 of the valve element 35 is in contact with the ring groove side surface 59 . The cover side 69 has a rib structure 71 so that there is a defined outflow cross section. Radial grooves 73 are formed via the rib structure 71 and the outflow cross section is determined via their cross sections.

The rib structure 71 is optionally implemented only on an outer surface area 75 of the cover side 69 of the valve element 35 . A radially inner surface area 77 is flat and has no profile. The radial extension of the closed inner surface area 77 can also be selected to be large enough that a guide edge 79 on the annular groove side surface 59 forms a slide valve with the rib structure 71 and the inner surface area 77, which keeps at least a remaining cross section of the outflow opening 67 open at all times.

In principle, the rib structure 71 can be molded into the cover side 69 . The dashed line below the top side is intended to symbolize that the rib structure can also be formed by at least one additional ring element 81 .

A further component of the slide valve described above can form the annular groove side surface 59 facing the cover side, which has a circumferentially extending groove 83 which partially defines the outflow cross section of the outflow opening. In the area of the groove 83 there is a particularly large outflow cross section. At this point there is also the possibility that the groove 83 of the annular groove side surface 59 is formed by an additional disk 85 which is preferably supported on an outer edge 87 of the valve carrier 29 .

In the synopsis of 2 and 3 it becomes clear that the groove 83 in the annular groove side surface 59 can have a different width over the circumference in order to prevent an abrupt narrowing of the outflow cross section of the outflow opening 67 .

The 4 shows a variant of a damping valve device 1 in which a rib structure on the top side 69 was dispensed with. Alternatively, the top side is divided into a radially inner raised area 89 and the outer surface area 75 . The raised area 89 has a lower height “h” than the height “H” of the leading edge 79, so that no form-fitting connection can occur between the raised area 89 of the cover side 69 of the valve element 35 and the groove 83 in the valve carrier 29. Furthermore, the guide edge 79 is spaced far enough from the raised area 89 in its radial position, so that no positive locking between the raised area 89 and the guide edge 79 can occur even when the valve element 35 is in a maximum expansion position. Here, too, the cover side 69 of the valve element 35 and the annular groove side surface 59 form a slide valve with which the cross section of the outflow opening can be changed depending on the radial expansion movement of the valve element 35 .

Reference List

1

damping valve device

3

vibration damper

5

first damping valve

7

dampening valve body

9

piston rod

11

cylinder

13

working space on the piston rod side

15

working space away from the piston rod

17

passage channels

19

passage channels

21

valve disc

23

valve disc

25

cable stop

27

piston rod guide

29

valve carrier

31

elastomeric element

33

ring groove

35

valve element

37

throttle point

39

inner wall

41

return spring

43

lateral surface

45

throttle cross-section

47

valve seat surface

49

valve seat surface

51

support washer

53

support washer

55

inner surface

57

ring groove side face

59

ring groove side face

61

ring groove footprint

63

pressure room

65

inflow opening

67

outflow opening

69

cover page

71

rib structure

73

radial groove

75

outer surface area

77

inner surface area

79

leading edge

81

additional ring element

83

groove

85

additional disc

87

outer edge

89

raised area

Claims (5)

Damping valve device (1) with a throttle point (37) for a vibration damper (3), comprising a valve carrier (29) with an annular groove (33) in which a valve element (35) with a variable diameter is arranged, the valve element (35) having a flow guide surface (39) forms the throttle point (37), the cross section of which reduces with increasing flow speed of a damping medium within the throttle point (37), the annular groove (33) having a lateral surface (67) of the valve element (35) and annular groove side surfaces (57; 59) of the valve carrier (29) form a pressure chamber (63) which is connected to a working chamber (13) of the vibration damper (3) via an inflow opening (65) and an outflow opening (67), with the annular groove side surface (59) and a Top side (69) of the valve element (35) an outflow cross section of the outflow opening (67) is limited, the size of which is determined by the radial expansion of the valve element (35) relative to the valve carrier (29), d a characterized in that the outflow cross section of the outflow opening (67) has a maximum in an initial position of the valve element (35) in conjunction with a maximum cross section (45) of the throttle point (37), in that the top side (69) of the valve element (29) is on a outer surface area (75) has a rib structure (71) and the annular groove side surface (59) of the valve carrier (29) facing the top side (69) has a groove (83) extending in the circumferential direction, which at least partially define the outflow cross section of the outflow opening (67). damping valve device claim 1 , characterized in that the rib structure (71) is formed by at least one additional ring element (81). damping valve device claim 1 , characterized in that the groove (83) of the annular groove side surface (59) is formed by an additional disk (85). damping valve device claim 3 , characterized in that the additional disk (85) is supported on an outer edge (87) of the valve carrier (29). Damping valve device according to at least one of Claims 1 to 4, characterized in that the groove (83) in the annular groove side surface (59) has a different width over the circumference.

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