WO2022175253A1

WO2022175253A1 - Damping valve device having a progressive damping force characteristic curve

Info

Publication number: WO2022175253A1
Application number: PCT/EP2022/053648
Authority: WO
Inventors: Hartmut Rölleke; Aleksandar Knezevic; Mathias Balensiefer; Jörg Rösseler
Original assignee: Zf Friedrichshafen Ag
Priority date: 2021-02-16
Filing date: 2022-02-15
Publication date: 2022-08-25
Also published as: DE102021201438B3

Abstract

The invention relates to a damping valve device (1) for a vibration damper (3), comprising a throttle point (31) connected to a valve element (29) which can be transferred from a through-flow position into a throttle position depending on the flow velocity of a damping medium inside the throttle point (31), wherein the valve element (29), as an annular element of variable diameter, moves in the closing direction with an increasing flow velocity of the damping medium inside an annular groove (27) of a valve support (25), wherein the annular groove (27) is designed as a pressure chamber (55) which has two through-flow directions and has at least one inflow opening (57) and at least one outflow opening (59) as connection openings, wherein the effective inflow opening (57) has a larger cross-section than the effective outflow opening (59), and an outlet cross-section (63) for the damping medium coming out of the pressure chamber (55) is controlled via a valve device (61), wherein the valve support (25) forms a movable valve body of the valve device (61).

Description

Damping valve device with progressive damping force characteristic

The invention relates to a damping valve device with a progressive damping force characteristic according to the preamble of patent claim 1.

DE 102016210790 A1 describes a damping valve device for a vibration damper, which includes a first damping valve which, in a first operating range, transitions into an open operating position as the flow rate of a damping medium increases. The first damping valve is formed, for example, by a piston valve or a bottom valve of the vibration damper. A second operating range with a progressive damping force characteristic of the vibration damper is influenced by a throttle point in connection with a valve body, which can be converted from an open position to a throttle position independently of the stroke position of a piston rod of the vibration damper as a function of the flow velocity within the throttle position. the valve body moves in the closing direction with increasing flow rate of the damping medium. This generates an additional damping force that makes it unnecessary to use a conventional tension or compression stop, which is only effective in one end position of the piston rod.

The throttling point and the damping valve are arranged hydraulically in series, with the valve body being designed as a ring element with variable diameter, which executes a radial closing movement in the direction of a flow control surface, in which a defined minimum passage cross section is maintained.

DE 102019212966 A1 proposes that the ring element, which can be changed in diameter, is additionally supported by a compressive force within a pressure chamber formed by a ring groove. The function of the pressure chamber is particularly effective when the cross section of an inflow opening is larger than an outflow opening of the pressure chamber. With regard to the damping behavior of a vibration damper, the use of two throttling points makes sense, depending Weil a throttle point for a working direction of the vibration damper. In terms of costs, however, it makes sense to limit it to a damping valve device with a throttle point that is optimally effective for both flow directions.

The object of the present invention is to solve the problem known from the prior Tech technology.

The object is achieved in that the annular groove is designed as a pressure chamber with two flow directions, which has at least one inflow opening and at least one outflow opening as connection openings, the effective inflow opening having a larger cross section than the effective outflow opening, and an outlet cross section for the damping medium is actuated from the pressure chamber via a valve device, the valve carrier forming a movable valve body of the valve device.

In the simplest design, the valve device can be realized without additional components. Consequently, there is also no additional installation space for the additional function of the two flow directions.

So that dirt and component tolerances have as little effect on functional reliability as possible, the valve device is designed as a seat valve.

A simple routing of the flow of the damping medium into the pressure chamber is achieved in that an inner lateral surface of the valve carrier delimits at least one connection channel to the pressure chamber. The inner surface can, for. B. form a geometrically very precise connection channel with egg ner lateral surface of the piston rod of the vibration damper.

Provision can also be made for at least one connection opening to the pressure chamber to be made on the inner lateral surface. The exit sides of the connection openings are easily accessible for post-processing, so that the risk of burr formation is minimized. For precise control of the movement of the valve carrier, the valve carrier is guided so that it can move axially between a first and a second stop.

So that the at least one stop does not have a disruptive effect on the flow conditions on and in the damping valve device, at least one of the stops is arranged radially within a pitch circle diameter determined by the at least one connection opening.

In a further function, at least one of the stops represents a component that determines the size of the outlet cross section.

For this purpose, one can provide, for example, that at least one stop disk is designed with a profile that determines the outflow cross section. Depending on the required damping force behavior, the damping force characteristics of the damping valve device can be influenced by selecting the stop disc.

Optionally, the valve carrier is positioned in a defined starting position by means of a spring arrangement. The valve carrier thus performs a defined valve lift movement, starting from a standstill.

Another option is that the pressure chamber is equipped with a pressure relief valve to prevent damage to the damping valve device or the vibration damper.

A possible design of the pressure relief valve is that a possibly already existing spring arrangement is part of the pressure relief valve.

Based on the following description of figures, the invention will be explained in more detail who the. It shows:

Fig. 1 Section of a vibration damper in the area of the damping valve device Fig. 2 and 3 Damping valve device according to Fig. 1 4 and 5 damping valve device with a pressure relief valve

FIG. 1, in combination with FIGS. 2 and 3, shows a damping valve device 1 for a vibration damper 3 of any design, 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 and fastened to a piston rod 9 .

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

For example, a valve carrier 25 is net angeord to be axially movable on the piston rod 9 . The valve carrier 25 has a circumferential annular groove 27 in which a variable diameter valve element 29 is guided. This valve element 29 is radially movable or radially elastic and forms a valve body for a throttle point 31 as part of the damping valve device 1. The valve element 29 forms the throttle point 31 with an inner wall 33 of the cylinder 11, the inner wall representing a flow guide surface.

On the top side, the valve element 29 carries a return spring 35, as shown on an enlarged scale in FIG. Between the inner wall 33 and an outer surface 37 of the valve element 29 Mantelflä is a variable throttle cross section 39 which generates an additional damping force.

At a piston rod speed in a first operating range, e.g. B. dress ner 1m / s, the throttle point 31 is fully open. The damping force is then only from the passage channels 17; 19 in connection with the valve discs 21; 23 he begets. When the valve disks 21; 23 lift the valve discs 21; 23 from its valve seat surface 39; 41 onwards The lifting movement of the valve disk 21; 23 is in each case supported by a support disk 43; 45 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 29 changes to a throttle position and performs a closing movement in the direction of the flow guide surface 33. Due to the high flow rate of the damping medium in the throttle point 31 formed as an annular gap, a negative pressure is formed, which leads to a radial expansion of the valve element 29 alen. However, so that the throttle point cannot become blocked under any circumstances, the return spring 35 maintains the defined minimum passage cross section. Alternatively, the valve element 29 can have a profiling of the outer lateral surface 37 or the valve carrier 25 has a mechanical stop for the valve element 29.

FIG. 2 shows an enlargement of the damping valve device 1 according to FIG. 51 and an annular groove base 53 forms a pressure chamber 55 which is connected to the working chamber 13 of the vibration damper 3 via an inflow opening 57 and an outflow Publ opening 59 . The pressure chamber 55 brings about, via the inner lateral surface 47 , an additional force component which is directed radially outward and expands the valve element, which supports the negative pressure situation prevailing in the throttle point 37 .

The annular groove 27 leads out as a pressure chamber 55 with two flow directions. The dimensioning rule is that the effective inflow opening 57 has a larger cross section than the effective outflow opening 59. Due to the changing flow direction of the damping valve device and thus also the pressure chamber, the openings also change their function, i.e. for a flow direction, one opening forms the inflow opening and the Opening in the other side wall of the ring groove is the outflow opening, see Fig. 3. With the opposite direction of flow, the functions consequently change. For this operating behavior, the damping valve device 1 has a valve device 61 via which a Outlet cross section 63 can be switched into the pressure chamber 55 depending on the direction of flow. The valve carrier 25 forms a movable valve body of the valve device 61 which is slidably mounted on the piston rod 9 . Since the valve carrier 25 is between a first and a second stop 65;

67, both of which are attached to the piston rod 9, and an inner lateral surface 69 of the valve carrier 25 out.

In this exemplary embodiment, the inner lateral surface 69 of the valve carrier 25 delimits at least one connection channel to the pressure chamber. The damping valve device has two axially extending connection channels 71 for each direction of flow; 73, which by means of an annular seal 75, z. B. in a groove of the piston rod 9, are hydraulically separated. Both connection channels 71 ; 73 are connected to the workroom 13.

Between the connection channels 71 ; 73 and the pressure chamber 55, there is a flow connection to the pressure chamber 55 via the at least one connection opening or inflow opening and outflow opening on the inner lateral surface 69.

An inflow opening into the pressure chamber 55 is formed for a flow direction from the connection opening. Although the damping medium flows out of the pressure chamber via the downstream connection opening in the direction of flow, at least one of the stops 65; 67 is a component that determines the size of the outlet cross section 63, in that the stop has a profile, e.g. B in the form of a notch. For example, at least one stop disk 77; 79 be designed with a profile that determines the discharge cross-section. The stop disk 77; 79 is also threaded onto the piston rod 9 and is based z. B. on a shoulder of the piston rod or a locking ring.

FIG. 2 shows the flow against the valve carrier 25 or the damping valve device 1 during an inward movement of the piston rod. The damping medium flows through the damping valve 17; 21 in the piston 7 and thereby fills the working chamber 13. As a result, the valve carrier 25 rests against the upper stop 65. The damping medium flows through the axial channel 73 and the connection opening, which now forms the inflow opening into the pressure chamber 55, exerts a radial pressure force there on the valve element 29 and flows via the connection opening = outflow opening 59 into the upper axial channel 71. The effective outlet cross section 63 is formed by the stop 65, since the notch or the groove has a smaller cross-section than the inflow opening 57 into the pressure chamber 55.

When the piston rod extends, the damping valve device 1 behaves as shown in Fig. 3. The valve carrier 25 moves on the piston rod 9 in the direction of the lower stop 65 on the piston side. The damping medium can enter the pressure chamber 55 via the comparatively large axial passage 71 and the connection opening 59 flow in, flow out again via the connection opening 57 and generate a pressure gradient via the open outlet cross section 63 in the stop 67, so that the inflow cross section into the pressure chamber 55 is also larger here than the effective outlet cross section 63 in the stop 67.

Because of the stop function of the valve carrier 25 on the stops 65; 67 and the resulting size of the effective outlet cross section 63 forms the Ven tilträger 25 part of a seat valve.

FIGS. 4 and 5 show a damping valve device 1 in which the valve carrier is positioned in a defined starting position by means of a spring arrangement 81 . Such a spring arrangement 81 is also possible and useful in the embodiment according to FIGS. The spring arrangement 81 comprises at least two springs 83 acting in opposite directions; 85, which is z. B. on the piston rod 9 end support zen and at least indirectly on a cover page 87; 89 of the valve carrier 25.

Another difference from FIG. 2 is that the pressure chamber 35 is equipped with a pressure relief valve 91; 93 is equipped. At a pressure level above a limit pressure, one of the valve disks 95; 97, which on the cover page 87; 89 of the valve carrier 25 rest against the force of the springs 83; 85 of the spring arrangement 81 from the top side 87; 89 and completely release the connection opening. As a result, the spring arrangement 81 is a component the relief valves 91; 93. In the opposite direction of flow, valve disks 95; 97 of the pressure relief valves 91; 93 the inflow opening 57; 59 in the starting position. When there is a flow against the damping valve device 1, the valve carrier 25 moves away from the valve disk 95 facing the flow; 97 and thus releases the full cross-section of the connection opening. The ring-shaped stop 71 ensures that the spring 85; 83 retains at least a residual spring deflection that is necessary for the function of the overpressure valve 91 ; 93 is provided. In the embodiment according to FIG. 4 the stop is designed radially on the outside of the spring arrangement 81 . In practice, the stops enclose the spring arrangement 81 over a length section.

5 is intended to show that the stop 65; 67 can also be designed radially inside the spring arrangement 81. The sleeve-shaped stop 65; 67 dips into a shoulder of the inner lateral surface 69 of the valve carrier. In a direct comparison to FIG. 4, it can be seen that at least one of the stops 65; 67 radially inside one of the at least one connection opening 57; 59 bestimm th pitch circle diameter 99 is arranged. This results in favorable conditions for the damping medium flowing into and out of the pressure chamber 55 .

Reference sign

damping valve device

Vibration damper first damping valve

dampening valve body

piston rod

Cylinder working space on the piston rod side working space away from the piston rod

passage channels

valve disc

valve carrier

ring groove

valve element

throttle point

inner wall

return spring outer surface

valve seat surface

support washer

Support washer inner lateral surface

ring groove side face

ring groove footprint

pressure room

inflow opening

outflow opening Valve device outlet cross-section first stop second stop inner lateral surface of the valve carrier

connecting channel

ring seal

stop washer

spring assembly

Feather

cover page

pressure relief valve

valve disc

pitch diameter

Claims

patent claims

1. Damping valve device (1) for a vibration damper (3), comprising a throttle point (31) in connection with a valve element (29) which, depending on the flow rate of a damping medium within the throttle point (31), can be converted from an open position to a throttle position , wherein the valve element (29) moves in the closing direction as an annular element with a variable diameter as the flow rate of the damping medium increases within an annular groove (27) of a valve carrier (25), characterized in that the annular groove (27) acts as a pressure chamber (55) with two flow directions, which has at least one inflow opening (57) and at least one outflow opening (59) as connection openings, the effective inflow opening having a larger cross section than the effective outflow opening, and an outlet cross section (63) for the damping medium from the Pressure chamber (55) controlled via a valve device (61). rt is, wherein the valve carrier (25) forms a movable valve body of the valve device (61).

2. Damping valve device according to claim 1, characterized in that the Venti leinrichtung (61) is designed as a seat valve.

3. Damping valve device according to claims 1 or 2, characterized in that an inner lateral surface (69) of the valve carrier (25) delimits at least one connection channel (71; 73) to the pressure chamber (55).

4. Damping valve device according to claim 3, characterized in that at least one connection opening (57; 59) to the pressure chamber (55) on the inner surface surface (69) is executed.

5. Damping valve device according to Claims 1 to 4, characterized in that the valve carrier (25) is guided so as to be axially movable between a first and a second stop (65; 67).

6. Damping valve device according to claim 5, characterized in that at least one of the stops (65; 67) is arranged radially within one of the at least one connection opening (57; 59) determined pitch circle diameter.

7. Damping valve device according to at least one of Claims 5 and 6, characterized in that at least one of the stops (65; 67) represents a component which determines the size of the outlet cross section (63).

8. Damping valve device according to claim 7, characterized in that at least one stop disc (77; 79) is designed with a profile that determines the outlet cross-section (63).

9. Damping valve device according to at least one of claims 1 to 8, characterized in that the valve carrier (25) is positioned in a defined starting position by means of a spring arrangement (81).

10. Damping valve device according to at least one of claims 1 to 9, characterized in that the pressure chamber (55) is equipped with a pressure relief valve (91; 93).

11. Damping valve device according to claim 10, characterized in that the spring arrangement (81) is part of the pressure relief valve (91; 93).