DE102019216709A1 - Vibration damper with a seal between two work spaces - Google Patents

Abstract

Vibration damper, comprising two working spaces which are separated from one another by a wall, the wall having a space-forming groove with a rectangular cross-section for a ring seal which is pretensioned by a cylinder wall, the space being joined by a further space in the pretensioning direction of the ring seal a cross-section that narrows starting from the first space is connected.

Description

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

The DE 195 08 853 A1 describes a vibration damper with adjustable damping force, which has two working spaces separated by a wall. A groove is formed in the wall in which an annular seal is chambered. Due to the working movements of the vibration damper, the ring seal is alternately loaded. In the DE 195 08 853 A1 options for constructing the wall are shown.

In the "Technical Manual 2007", page 564, from Freudenberg Simrit GmbH & Co. KG, Table 13 shows that the intended groove for an O-ring can have a rectangular to a slightly trapezoidal cross-section. The angle enclosed by the groove base and a groove side surface must not exceed 95 °.

In practice, measurements of the damping force have shown that if the groove was designed in accordance with regulations, a slight dent occurred in the damping force characteristic. The cause was determined to be the sealing function of a seal between two working spaces, which, due to the alternating flow, always builds up the full sealing effect only with a slight delay. This delay manifests itself as a loss of damping force.

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

The object is achieved in that the space is adjoined in the prestressing direction of the ring seal by a further space with a cross section that narrows from the first space.

Due to the narrowing cross section of the second space, a force component is generated in the direction of the surface to be sealed. Overall, a displacement of the entire ring seal within the groove can be reduced.

In a further embodiment of the invention it is provided that the further space has a conical cross section. The behavior of the ring seal should be independent of the direction of flow. The conical cross-section shows a symmetrical sealing behavior. In principle, the cone can have a constant cone angle, but also a convex contour.

Tests have shown that the best effect can be achieved with a cone angle of at least 60 °.

With regard to a long service life, the further space has an offset-free connection width to the first space within the scope of the manufacturing accuracy. This results in a relatively smooth transition between the two working spaces, so that the ring seal is not damaged at a transition edge.

According to an advantageous dependent claim, the further space is adjoined by a third space to compensate for the thermal expansion of the ring seal. The ring seal must be usable in a temperature range of -40 ° to + 80 °. With the additional third space, a minimal gap between a groove side wall of the first space and the ring seal can be ensured, even at higher temperatures, in order to be able to use the hydraulic pressure to build up a preload on the ring seal.

Furthermore, it is provided that the third room is designed in series with the first and the second room. This arrangement prevents the ring seal from being displaced into the third space when pressure is applied.

The third room is designed symmetrically to the second room. Here, too, the point is that there should be no preferred direction for the flow for the sealing function.

In order not to allow the ring seal to enter the third space, the third space is connected to the second space when the ring seal is subjected to pressure. Since the second and third spaces have the same pressure level, the ring seal cannot be displaced into the third space.

If possible, the connection width between the second and third space should be selected so that when a flow approaches the ring seal, starting from one of the working spaces, a lifting movement begins from a side surface of the second space. Due to the large temperature range from -40 ° to + 80 °, the operating behavior of the ring seal can fluctuate greatly. It can therefore be useful if there is a pressure equalization connection between the second and the third space, which ensures a hydraulic connection between the second and the third space.

The installation space for the ring seal within the wall is limited. Therefore, the pressure equalization connection is preferred by at least a groove formed in side walls of the second and third spaces.

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

• 1 Darstellung der Anwendung der Erfindung bei einem Schwingungsdämpfer
• 2 u. 3 Detaildarstellung der Wandung von 1

It shows:

• 1 Illustration of the application of the invention to a vibration damper
• 2 u . 3 Detailed representation of the wall of 1

To illustrate the application of the invention, that known from the prior art is used 1 . It shows an adjustable vibration damper 1 with a cylinder 3 , in which a piston rod 5 along with a piston attached to it 7th performs an axial working movement. The piston rod 5 penetrates the cylinder 3 in each stroke position over the entire length, with the piston 7th is designed as an annular piston. The piston 7th can be equipped with a damping valve and / or a pressure relief valve for each direction of movement.

The cylinder 3 is completely covered by a container tube 9 enveloped. The container pipe has the end 9 over a floor 11 for the cylinder 3 . A piston rod guide 17th closes both the cylinder at the other end 3 as well as the container pipe 9 .

The cylinder has an annular connection block 19th on, which has two separate channels 21st ; 23 to a pumping device 25th and through two channels 27 ; 29 to a housing 31 with adjustable damping valves 33 ; 35 (see 2 ) has. The container pipe engages in an opening on the cover side of the connection block 19th a.

The bottom at the end 11 in turn, a transfer cylinder closes 13th which is also on the connection block 19th is attached and a connecting member 15th carries, as an example, a bracket is shown here as it is, for. B. from the DE 2932138 A1 is known.

The container pipe 9 has at least in the area of the piston rod guide 17th has a substantially identical outer diameter as the transfer cylinder 13th . Furthermore are the soil 11 and the piston rod guide 17th essentially identical in their geometry, so that the same component and the container tube can be used for both functions 9 and the transfer cylinder 13th can be produced from an identical semi-finished product.

The transfer tube 13th is from an end cap 20th locked so that the piston rod 5 is completely protected.

The container pipe 9 and the cylinder 3 form an annulus. Both a management-side work space 37 , a floor-side work space 39 as well as the annulus are completely filled with a damping medium. Both working spaces have the same cross section, so that when the piston rod moves, regardless of direction, a volume of damping medium with an identical cross section is displaced. Therefore, the vibration damper does not need a compensation space for the compensation of an extending and retracting piston rod, but only for a temperature compensation of the damping medium. The executive work area 37 is via at least one radial opening 41 in the cylinder 3 to a first annulus section 43 connected, in turn with the first channel 27 in the connection block 19th to the housing 31 connected is. The same construction principle is used for the working area remote from the piston rod 39 used, which is via the axial flow connection 15th in the centering ring 13th and a second annulus section 45 to the second channel 29 in the connection block 19th connected is. Both annulus sections 43 ; 45 are through a sealing partition 47 of the connection block.

Right on the case 31 with the adjustable damping valves 33 ; 35 is a memory 49 attached to that of the piston rod 5 compensates for displaced damping medium volumes.

The 2 shows the wall in simplified form 1 . The wall 47 has a first room 51 forming circumferential groove 53 with a rectangular cross-section for a ring seal 55 with a circular cross-section in the relaxed state, which is supported by a cylinder wall 57 of the cylinder 3 is biased radially. The width of the first room 51 is dimensioned so that the ring seal 55 unassembled state with low preload on the groove side surfaces 59 ; 61 can come to the plant. A slight gap between the groove side walls 59 ; 61 and the ring seal 57 does not affect the static sealing effect, but worsens the dynamic sealing effect. The first room 51 closes in the pretensioning direction of the ring seal 57 another room 63 with one starting from the first room 51 narrowing cross-section.

The further space has a conical cross section, a cone angle α being at least 60 °. In this representation there is a constant cone angle α. In principle, a convex conical shape would also be possible.

As the 2 further shows, shows the further room 63 An offset-free connection width to the first space within the scope of the manufacturing accuracy 51 on. The ring seal is based on conical surfaces 65 ; 67 which also increases the preload of the ring seal 55 on the cylinder wall 57 results. About the width and depth of the first room 51 you can dimension the preload of the ring seal. With a very flat and very wide first room 51 one would indeed be able to generate a high preload, but the assembly of the wall with the cylinder would be 3 because of the large protrusion of the ring seal 55 very difficult. A protrusion of 15 to 30% of the diameter of the ring seal 55 would be set.

The further or second room 63 a third room closes 69 to compensate for the thermal expansion of the ring seal 55 at. In this illustration, the third room has 69 a rectangular cross-section. The function is less dependent on the cross-section than on the volume of the third room 69 as the volume of the third room required for the compensation function 69 is essential.

The third room is preferred 69 in series with the first and second rooms 51 ; 63 executed to the ring seal 55 with a flow over a groove side surface 59 ; 61 of the first room 51 not to be able to displace into a third room opposite.

Furthermore is the third room 69 symmetrical about a central axis 71 of the first and second room 51 ; 63 designed for both directions of flow over the groove side surfaces 59 ; 61 to achieve the same sealing function.

As already explained above, the cross-sectional shape of the third space is 69 for the function of the ring seal 55 irrelevant. Connection width B of the third space is more important in this context 69 with the second room 63 . The connection width is preferably dimensioned such that the third space 69 when the ring seal is subjected to pressure 55 with the second room 63 connected is. It is impossible to give an exact measure in general, since z. B. the material of the ring seal plays a major role. The inside diameter and the cord diameter of the ring seal also have an effect 55 out.

The aim should be that between the second and the third room 63 ; 69 a pressure equalization connection 73 exists, which ensures that when there is a flow against the ring seal 55 in the high pressure state of the second space 63 and in the third room 69 the same pressure prevails so that the ring seal 55 not in the third room 69 is pushed in.

If the dimensioning instructions explained above cannot be implemented, the pressure compensation connection 73 alternatively by at least one groove 75 in the conical surfaces 65 ; 67 of the second room 63 and side faces 77 of the third room 69 are formed. (see 3 )

The 2 shows the ring seal 55 in the unloaded state. Both work rooms 43 ; 45 on both sides of the wall 47 have largely the same pressure level. Consequently, the ring seal 55 due to the shape of the second room 63 in the middle of the first room 51 held. As already mentioned, there is between the ring seal 55 and the groove side surfaces 59 ; 61 practically no bias in the first room.

In the event of a pressure load, for example from the work area 43 becomes the ring seal 55 on the opposite side wall of the groove 59 biased. The hydraulic working medium lifts the ring seal 55 also from the conical surface facing the higher pressure side 67 so that a hydraulic connection between the work area 43 , the first room 51 , the second room 63 and the third room 69 consists. Because of this pressure distribution, the ring seal 55 not disproportionately in the third room 69 repressed. Should the lifting movement be due to incalculable operating conditions at the ring seal 55 not be possible, then the groove can 75 act as a pressure equalization connection.

List of reference symbols

1

Vibration damper

3

cylinder

5

Piston rod

7th

piston

9

Container pipe

11

ground

13th

Transfer cylinder

15th

Connecting body

17th

Piston rod guide

19th

Connection block

20th

cap

21

channel

23

channel

25th

Pumping device

27

channel

29

channel

31

casing

33

adjustable damping valve

35

adjustable damping valve

37

Working space on the piston rod side

39

Working area remote from the piston rod

41

Radial opening

43

first annulus section

45

second annulus section

47

Wall

49

Storage

51

first room

53

Groove

55

Ring seal

57

Cylinder wall

59

Groove side surfaces

61

Groove side surfaces

63

another room

65

Conical surface

67

Conical surface

69

third room

71

Central axis

73

Pressure equalization connection

75

Groove

77

Side faces

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 19508853 A1 [0002]
• DE 2932138 A1 [0022]

Claims (10)

Vibration damper (1), comprising two working spaces (37; 39) which are separated from one another by a wall (47), the wall (47) having a groove (53) which forms a space (51) and has a rectangular cross-section for a ring seal ( 55) which is pretensioned by a cylinder wall (57), characterized in that the space (51) is adjoined in the pretensioning direction of the ring seal (55) by a further space (63) with a cross-section that narrows from the first space (51). Vibration damper after Claim 1 , characterized in that the further space (63) has a conical cross section. Vibration damper after Claim 2 , characterized in that a cone angle α is at least 60 °. Vibration damper after Claim 1 , characterized in that the further space (63) has an offset-free connection width to the first space (51) within the scope of the manufacturing accuracy. Vibration damper after Claim 1 , characterized in that the further space (63) is followed by a third space (69) to compensate for the thermal expansion of the ring seal (55). Vibration damper after Claim 5 , characterized in that the third space (69) is designed in series with the first and the second space (51; 63). Vibration damper after Claim 5 , characterized in that the third space (69) is designed symmetrically to the second space (63). Vibration damper after Claim 5 , characterized in that the third space (69) is connected to the second space (63) when the ring seal (55) is subjected to pressure. Vibration damper after Claim 8 , characterized in that there is a pressure equalization connection (73) between the second and the third space (63; 69). Vibration damper after Claim 9 , characterized in that the pressure equalization connection (73) is formed by at least one groove (75) in side walls (65; 67) of the second and third space.

Images