JPH06207633A - Shock absorber - Google Patents

Abstract

PURPOSE: To take advantages of both a two-tube type shock absorber and a single-tube type shock absorber by eliminating the drawbacks of both types. CONSTITUTION: A compensation chamber 30 is split into a liquid chamber 32 having a pressure medium and a gas chamber 34 separated from the liquid chamber 32 by a movable separating element 36, and a rod seal member 16 is split into an inner sealing location 18 facing an inner chamber 12 and a sealing location 20 opposite to the inner chamber. An intermediate chamber 50 provided between the sealing locations 18, 20 is connected to the liquid chamber 32 in the compensation chamber 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber for influencing two mass bodies that can move relative to each other, and more particularly to a shock absorber used in an automobile. One of the two mass bodies is a vehicle upper structure, and the other mass body is a wheel support that supports rotatable wheels.

[0002]

2. Description of the Related Art In a shock absorber, a piston rod usually projects from only one side of a cylinder. During the entry stroke of the piston rod into the inner chamber of the cylinder, the pressure medium is pushed inside the inner chamber by the piston rod, so that at least one compensating chamber, which is partially gas-filled, must be provided. I won't. Since this compensation chamber is connected to the inner chamber of the cylinder, the pressure medium can be pushed back from the inner chamber to the compensation chamber during the stroke of the piston rod, and must be supplied back from the compensation chamber to the inner chamber during the stroke. You can
This pressure medium is usually pressure oil.

There are shock absorbers in which an additional cylindrical tube surrounds this cylinder. In this case, an intermediate chamber is formed between the cylinder and the cylindrical tube, and this intermediate chamber is used as a compensation chamber. Significantly or necessarily, the mounting position of this type of shock absorber is such that the piston rod projects upward from the cylinder. Inside the cylinder, a piston rod is connected to the piston. The piston is provided with, for example, a preloaded first check valve, through which the pressure medium is squeezed out of the working chamber on the rod side during the outstroke and on the bottom side. Can flow into the work room. Through the second check valve, this pressure medium escapes from the work chamber on the bottom side to the work chamber on the rod side while being hardly throttled during the stroke. A first bottom-side check valve is provided in the area of the end face of the cylinder on the side opposite to the piston rod, through which the pressure medium flows from the compensation chamber during the stroke. It can flow into the work chamber on the bottom side with almost no squeezing. Second
On the bottom side, but via a preloaded check valve, the volume displaced by the piston rod during the entry stroke escapes from the bottom working chamber into the compensating chamber in a throttled state. This compensation chamber extends to the extent of the end face penetrated by the piston rod. Gas is present in this area of the compensation chamber, depending on the mounting position.
On the end surface of the cylinder penetrated by the piston rod, an inner sealing portion facing the inner chamber is provided between the compensation chamber and the inner chamber. This sealing point must be designed such that no gas can reach the rod-side working chamber from the compensating chamber during the entry / exit stroke. In addition, at this sealing point, the gas collected in the working chamber can escape to the compensation chamber in some cases. On the end face of the cylinder which is penetrated by the piston rod, a further outer sealing point is provided between the compensation chamber and the outer surface of the shock absorber. Since there is a relatively constant and not particularly high pressure in the compensation chamber, a shock absorber of this kind has the advantage that the frictional forces at this point are not particularly great. Such outer sealing points help prevent gas and pressure medium from escaping outward during the outstroke and ensure that no contaminants reach the interior of the shock absorber during the inbound stroke. It's becoming useful. In this type of shock absorber, the mounting position must be such that the piston rod projects upward from the cylinder. Since the compensation chamber is only partially filled with the pressure medium, the shock absorber can only be positioned obliquely in a limited extent. Such a shock absorber is usually called a two-tube shock absorber.

In addition to the two-tube type shock absorber described above, there is also a one-tube type shock absorber. In this type of shock absorber, the compensating chamber does not surround the cylinder, and normally the damping of the pressure medium for the entry and exit strokes is effected by a damping valve provided on the piston. During the entry stroke, so that the volume displaced by the piston rod can escape.
The work chamber on the bottom side is connected to the compensation chamber. The compensating chamber is preloaded with a correspondingly high pressure so that a sufficiently large force is produced during the entry stroke. Due to such preload pressure in the compensation chamber, the entire shock absorber is under relatively high pressure. During the stroke, a high pressure is generated in the working chamber on the piston rod side in proportion to the damping force. This high pressure must be sealed by a rod sealing member provided on the end face penetrated by the piston rod. This high pressure creates a high frictional force on the piston rod, which means that
It impairs comfortable driving characteristics and limits the useful life.

Comparing the two-tube type shock absorber and the one-tube type shock absorber, both structures show that
It has advantages and disadvantages compared to the structure of the opponent. If deciding to adopt either one of these structure shock absorbers, the automobile manufacturer must accept the drawbacks of that structure.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a shock absorber which has the advantages of avoiding the drawbacks of the two-tube shock absorber and the one-tube shock absorber. .

[0007]

In order to solve this problem, in the structure of the present invention, in a shock absorber for influencing the relative movement of two mass bodies, a cylinder having an inner chamber having a pressure medium is provided. A piston rod is provided, which penetrates one end surface of the cylinder, and the piston rod projects into the inner chamber,
Axially slidably supported with respect to the cylinder, the cylinder is coupled to one of the mass bodies, the piston rod is coupled to the other mass body, The end surface penetrated by the piston rod is sealed to the piston rod by the rod seal member, and the compensation chamber is further provided.
Between the compensation chamber and the inner chamber, at least valve means for restricting the flow of the pressure medium from the inner chamber to the compensation chamber is provided, and the compensation chamber is a liquid chamber having the pressure medium,
It is divided into a gas chamber separated from the liquid chamber by a movable separator, and the rod seal member has an inner seal portion facing the inner chamber and a seal portion opposite to the inner chamber. And the intermediate chamber provided between the two sealing points is connected to the liquid chamber of the compensating chamber.

[0008]

The shock absorber according to the present invention has one
It does not have the drawbacks of the tubular shock absorber and the two-tube shock absorber, but has its advantages. In particular, it responds very well to control signals, avoiding even the smallest waste strokes during reversal of movement (transition from the start stroke to the start stroke and vice versa), resulting in extremely small friction force. A shock absorber that has only that is obtained.

Even under adverse operating conditions, gas cannot dissolve in the pressure medium. Such gas may be generated from the pressure medium in some cases because the operating conditions in each shock absorber are constantly changing. This can adversely affect the damping characteristics of the shock absorber, especially the controllability. Since it is possible to easily prevent the pressure medium from being saturated by the melted gas, it is advantageous that no gas is generated from the pressure medium.

Advantageously, a small amount of gas, which may be present in the inner chamber of the cylinder, can escape to the compensation chamber. Advantageously, the gas chambers can be arranged very arbitrarily.

The measures as defined in claim 2 and subsequent claims make possible an advantageous alternative construction of the shock absorber according to claim 1.

In an advantageous construction, the inner sealing member between the compensation chamber and the inner chamber of the shock absorber is a gap packing. This is advantageous because it guarantees very low friction forces. This gap packing can at the same time serve as a piston rod. Since no special sealing value is required for this inner sealing member, a slit guide ring may be used as the piston rod guide. This makes the assembly of this guide ring extremely easy.

It is advantageous if the compensating chamber is constructed as an annular chamber extending so as to surround the cylinder, since a particularly compact construction is obtained.

If this compensating chamber has a gas chamber separated by a diaphragm and another gas chamber separated by a separating piston, an extremely sturdy structure with less hysteresis can be obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Three embodiments of the present invention will be described in detail below with reference to the drawings.

The shock absorber according to the invention can be used whenever it is desired to influence the relative movement of two masses which are movable relative to each other. This shock absorber, especially in automobiles,
It is used to influence between the vehicle superstructure and the wheel supports that support the wheels.

1 to 3 show an important part of the present invention. The various intermediate chambers inside the shock absorber have been shortened in order to show the important parts as large as possible without wasting space. For the same reason, FIGS. 1 to 3 always show only the right half of the shock absorber. It is easy to correspondingly supplement the other half of the shock absorber.

In the embodiment shown in FIG. 1, the damping force can be generated during the traveling stroke, that is, when the piston rod enters the shock absorber. In the embodiment shown in FIGS. 2 and 3, it is possible to damp the movement of the pivotally mounted mass during both the entry and exit strokes.

FIG. 1 shows a shock absorber having a cylinder 2 and a piston rod 4. The cylinder 2 has an outer peripheral tube 6, a first end surface 8 and a second end surface 10. Surrounded by the outer peripheral tube 6 and both end surfaces 8 and 10,
An inner chamber 12 is formed in the cylinder 2. This interior room 1
2 is filled with liquid as a pressure medium. The first end face 8 faces upwards and has a cylinder opening 14. Through this cylinder opening 14, the piston rod 4 can enter the inner chamber 12 of the cylinder 2 from the outside. This piston rod 4 is in the cylinder opening 14,
It is supported so as to be slidable in the axial direction.

In order to close the inner chamber 12 of the cylinder 2 to the outside, the cylinder opening 14 is provided with a rod seal member 16 between the first end face 8 and the piston rod 4. The rod seal member 16 mainly comprises an inner seal point 18 and an outer seal point 20. The inner sealing point 18 faces the inner chamber 12 and the outer sealing point 20 points around the shock absorber.

The piston rod 4 is connected to the first mass 22 in the region of the end of the piston rod 4 which is remote from the inner chamber 12. The cylinder 2 has a second mass 24
Is linked to or is bound to. The first mass 22 is, for example, a vehicle superstructure, and the second mass 24 is, for example, a wheel support such as an axle, that is, an axle on which wheels (not shown) are supported.

A compensation chamber 30 is provided in this shock absorber. The compensation chamber 30 has a liquid chamber 32 and a gas chamber 34. A moveable separator 36 separates the gas chamber 34 from the liquid chamber 32. The movable separator 36 is constructed as follows. That is, the gas existing in the gas chamber 34 is configured so as not to be mixed with the pressure medium existing in the liquid chamber 32. In addition, the movable separator 36 is
It is configured to be movable so that the pressures are substantially equal on both sides of. The separating body 36 is, for example, a movable wall.
In the embodiment shown in FIG. 1, this moveable separator 36 is a diaphragm. However, instead of the diaphragm, for example, a shiftable separating piston may be used. The gas in the gas chamber 34 of the compensation chamber 30 is preloaded by a predetermined preload pressure.

The compensation chamber 30 is connected to the inner chamber 12 via the connecting portion 38.
It is connected to the. Valve means 40 is provided in the direction in which the connecting portion 38 extends. This valve means 40 is formed as follows. That is, the flow of the pressure medium is
That is, it is formed so as to be narrowed from the direction toward the compensation chamber 30. The valve means 40 may be arranged such that the throttle amount is variable in relation to the control signal acting on the valve means 40. In the illustrated embodiment, the valve means 40 comprises a check valve 42 and a preloaded check valve 44. The preloaded check valve 44 serves to throttle the pressure medium as it flows from the inner chamber 12 to the compensation chamber 30. The check valve 42 allows the pressure medium from the compensation chamber 30 to reach the inner chamber 12 of the cylinder 2 with almost no throttling.

A cylindrical tube 46 surrounds the outer peripheral tube 6 at radial intervals. The connection 38 between the compensation chamber 30 and the inner chamber 12 extends through the intermediate chamber between the outer peripheral pipe 6 and the pipe 46. This part of the connection 38 between the valve means 40 and the gas chamber 34 can be referred to as a component of the liquid chamber 32.

A circumferentially extending intermediate chamber 50 is formed between the inner seal point 18 and the outer seal point 20. The intermediate chamber 50 is provided with a compensation chamber 3 via a passage 52.
It is connected to 0. Intermediate chamber 50, passage 52, and liquid chamber 3
2 and at least a part of the connection part 38 are filled with a pressure medium and form a part of the compensation chamber 30. A relatively low pressure is also present in the liquid chamber 32 and thus in the intermediate chamber 50. This pressure corresponds to the preload pressure in the gas chamber 34 and is extremely lower than the maximum pressure generated in the inner chamber 12.

Since the pressure in the intermediate chamber 50 is significantly lower than the maximum pressure in the inner chamber 12, the pressure difference at the inner sealing point 18 is particularly high during the rapid entry stroke (the embodiment of FIG. 1) or It is relatively large during the rapid extension stroke (the embodiment of FIGS. 2 and 3). Since the sealability of the inner sealing point 18 is small, a simple sealing member may be used for the sealing point 18 despite the high pressure difference. In particular, the friction in the area of the sealing point 18
It may be noted that it is small even if the pressure in the inner chamber 12 is very high. Therefore, at the inner seal point 18,
It is often advantageous to form the sealing point 18 as a gap packing rather than using an elastic sealing ring that crimps against the piston rod 4.

Since there is a relatively low pressure in the intermediate chamber 50, which is significantly lower than the maximum pressure in the inner chamber 12, only the relatively low pressure is sealed at the outer sealing point 20. Just do it. This has a very advantageous effect on the selection of the sealing element provided at the sealing point 20. The sealing element provided at the outer sealing point 20 may be configured so that it produces only very small frictional forces. Since the pressure in the intermediate chamber 50 is relatively small,
The sealing ring provided at the outer sealing point 20 is pressed against the piston rod 4 only by a relatively low pressure. This allows a small frictional force.

Since the liquid chamber 32, and thus the intermediate chamber 50, is separated from the gas chamber 34 by the movable separator 36, there is no risk that some gas will be brought into the inner chamber 12 during the travel stroke.

The liquid chamber 32, or the connection 38 associated with this liquid chamber 32, may be connected to the pressure source 54 via a conduit shown in broken lines if necessary. With this pressure source, level control is possible, for example. However, this pressure source 54 may instead be connected to the inner chamber 12. The illustration of this variation is omitted for the sake of clarity. In the region of the first mass, an electronic control unit 56 may be provided, by means of which the valve means 40 and / or the pressure source 54 can be controlled.

FIG. 2 shows another advantageous construction of the shock absorber according to the invention.

In all the drawings, the same or similar parts are designated by the same reference numerals. The following embodiment has a wide range of similar configurations to those of the first embodiment shown in FIG. 1 except for the following differences. The individual parts of the different embodiments can be combined with one another.

In the embodiment shown in FIG. 2, the inner chamber 12
A damping piston 60 is fixed to the end of the piston rod 4 that has entered into the. The damping piston 60 divides the inner chamber 12 into a first working chamber 61 and a second working chamber 62, and is axially slidably supported inside the outer peripheral pipe 6.

At least a part of the pressure medium is provided in both working chambers 6.
Between 1, 62, they can be exchanged with each other through the throttling means 66. This throttle means 66 is preferably arranged on the damping piston 60. In the embodiment shown in FIG. 2, this throttle means 66 has a check valve 67 and a preloaded check valve 68. During the stroke, the pressure medium can reach the second working chamber 62 from the first working chamber 61 through the preloaded check valve 68. In this case, the pressure medium is throttled through the preloaded check valve 68 and an appropriate damping force is produced. Additionally, pressure medium may flow from the compensating chamber 30 through the check valve 42 into the second working chamber 62 during this outstroke. During the entry stroke, part of the pressure medium reaches the first working chamber 61 from the second working chamber 62,
Another pressure medium flows through the preloaded check valve 44. Thereby, an appropriate damping force is formed.

In the embodiment shown in FIG. 2, the compensation chamber 3
0 is a liquid chamber 32a, 32b and a gas chamber 34a, 34
b. Separator 36 constructed in the form of a gas bag
The a can prevent the gas from reaching the liquid chamber 32a from the gas chamber 34a. Another separating body 36b, which is formed in the form of a separating piston, is arranged so that the liquid chamber 32b is appropriately gas chamber 34b.
Separate from.

In FIG. 2, the inner sealing point 18 is a gap packing, which also serves for guiding the piston rod 4. Outside seal part 2
The groove 0 is provided with a grooved ring which, with a slight pressing force, prevents the pressure medium from leaking out of the cylinder 2, with which one edge serves as a wiping element. This eliminates the risk of dirt reaching the cylinder 2 from the outside.

FIG. 3 shows another advantageous embodiment. In contrast to the embodiment shown in FIGS. 1 and 2, in the embodiment shown in FIG. 3, the compensation chamber 30 as a whole including the gas chamber has a cylinder 2 and a cylindrical tube formed by stepping. It is located inside the intermediate chamber between 46. Movable separator 3
6 is a diaphragm, on the other hand, on the first end face 8,
On the other hand, since it is fixed to the pipe 46, the intermediate chamber between the cylinder 2 and the pipe 46 is roughly seen, with the liquid chamber 32 located towards the center and towards the outside, ie the pipe 4
The gas chamber 34 is located toward the position 6. The moveable separator 36 has the shape of a substantially flexible hose.

In addition, the range of the rod seal member 16,
That is, the check valve 70 is provided in the range of the first end surface 8. This check valve 70 is provided in the first working chamber 61 in a state where the pressure medium is hardly throttled from the liquid chamber 32 of the compensation chamber 30.
Connected so that you can reach. However, reverse flow is blocked by the check valve 70. This means that no matter how large the throttle means 66 is closed during the travel stroke, the pressure in the first working chamber 61 is a predetermined value, that is,
This has the advantageous effect that there is no risk of the pressure falling significantly below the preload pressure in the gas chamber 34. As a result, the pressure in the first working chamber 61 does not drop to such an extent that it reaches the vapor pressure range of the pressure medium. In the embodiment shown in FIG. 3, both the damping force for the entry stroke and the damping force for the extension stroke are adjusted by the throttle means 66.
For this purpose, the diaphragm means 66 is connected to the electronic control unit 56 via an electrical line 72.

In the region of the inner sealing point 18, a guide ring 73 of bearing material is additionally arranged in FIG. For good guidance of the piston rod 4, this sealing point 18 may be formed in the form of a rod guide with a separate guide ring 73. Advantageously, if the guide ring 73 is axially slit, the sealing properties are not impaired, which significantly improves the assemblability of this guide ring 73, as well as the friction force and the guide force. The properties are also significantly improved.

A wiping member 74 is further located outside the outer sealing point 20. This wiping member has a grooved ring disposed at the outer sealing point 20 during the running stroke, which causes contamination particles to be generated. Prevent from being damaged by.

In the shock absorber constructed according to the present invention, the liquid chamber 32 is separated from the gas chamber 34, so that there is no possibility that gas exists in the upper region of the liquid chamber 32, that is, the region of the check valve 70. Therefore, in this embodiment, the pressure medium is supplied from below by a separate conduit to the check valve 7.
It is not necessary to supply 0. For the same reason, it is not necessary to configure the inner sealing part so that the medium is not brought into the inner chamber 12 during the traveling stroke. In any case, the gas that adversely affects the damping characteristics is
This is because it is guaranteed that there is no fear of reaching.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a shock absorber according to the present invention.

FIG. 2 is a sectional view showing a second embodiment of the shock absorber according to the present invention.

FIG. 3 is a sectional view showing a third embodiment of the shock absorber according to the present invention.

[Explanation of symbols]

2 cylinders, 4 piston rods, 6 peripheral tubes,
8, 10 End face, 12 Inner chamber, 14 Cylinder opening, 16 Rod sealing member, 18, 20 Sealing point, 22, 24 Mass body, 30 Compensation chamber, 32,
32a, 32b liquid chamber, 34, 34a, 34b gas chamber, 36, 36a, 36b separator, 38 connection part, 40 valve means, 42, 44 check valve, 46
Pipe, 50 intermediate chamber, 52 passage, 54 pressure source,
56 electronic control unit, 60 damping piston, 61, 6
2 working chambers, 66 throttle means, 67, 68, 70
Check valve, 72 conduit, 73 guide ring, 74
Wiping member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Andreas Krug, Federal Republic of Germany Stuttgart Foyerbacher Weg 15 (72) Inventor Peter Zeiner, Germany Stuttgart Jupiter Weg 14 (72) Inventor Dieter Wiltsch, Brackenheim Alte Schmeide 32 (72) Inventor Andrew-William Kingston Germany Korntal-Mün Hingen Butzengasse 3 (72) Inventor Stephan Beier Germany Ditzingen Hohe Strasse 31 (72) Inventor Andreas Berner Germany Prohingen Esli Ngerst Rase 192 (72) Inventor Manfred Gerdes Germany Korntal-Mün Hingen Christoph Strasse 22 (72) Inventor Hans Hecker Germany Sachsenheim Hohe Strasse 31 (72) Inventor Tobias Hafner Germany Stuttgart Taichhofn Strasse 6 (72) Inventor Dieter Kava Germany Erdmannhausen Sommerharden Strasse 20 (72) Inventor Martin Kirschner Germany Stuttgart Kissinger Strasse 52 (72) Inventor Steffen Schneider Germany Federal Tam Brechter Strasse 62 (72) 72) Inventor, Halalt Spiel, Federal Republic of Germany Freiberg Graf-Adelmann-Strasse 31 (72) Inventor, Ewald Sci Piece Germany Vaihingen Gin Star Weserblick click 3 (72) inventor Michael Tissha Germany Abstatt sila over Strasse 14 (72) inventor Jürgen Lampe Germany Stuttgart les over Te Bahnhofstrasse 11

Claims (13)

[Claims] 1. A shock absorber for influencing the relative movement of two mass bodies is provided with a cylinder having an inner chamber with a pressure medium, the piston rod penetrating one end face of the cylinder. Is provided, the piston rod projects into the inner chamber, and is axially slidably supported with respect to the cylinder, the cylinder being coupled to one of the both mass bodies. The piston rod is coupled to the other mass body, the end surface penetrated by the piston rod is sealed to the piston rod by a rod seal member, and a compensation chamber is further provided. Between the compensation chamber and the inner chamber, at least valve means for restricting the flow of the pressure medium from the inner chamber to the compensation chamber is provided, and the compensation chamber (30) Is divided into a liquid chamber (32) having the pressure medium and a gas chamber (34) separated from the liquid chamber (32) by a movable separator (36), and the rod seal member ( 16) is divided into an inner sealing portion (18) facing the inner chamber (12) and a sealing portion (20) on the opposite side of the inner chamber, and both sealing portions (18, 20) Between the liquid chamber (3) of the compensation chamber (30).
A shock absorber characterized in that it is connected to 2). 2. The end of the piston rod (4) protruding into the inner chamber is connected to a damping piston (60), which penetrates the inner chamber (12) by the piston rod. The first working chamber (61),
A second working chamber (62), the pressure medium being at least partially exchangeable between the two working chambers (61, 62) via a throttle means (66), A shock absorber according to claim 1, wherein two working chambers (62) are connected to the compensation chamber (30) via the valve means (40). 3. The throttling means (66) is adapted to enable a substantially unthrottled flow of pressure medium from the second working chamber (62) to the first working chamber (61). And the valve means (40) is adapted to allow an almost unthrottled flow of pressure medium from the liquid chamber (32) of the compensation chamber (30) to the second working chamber (62). The shock absorber according to claim 2, which is present. 4. The shock absorber according to claim 2, wherein the throttling action of the pressure medium is controllable in at least one flow direction by a control signal acting on the throttling means (66). 5. The connection (7) monitored by a check valve.
0) from the liquid chamber (32) to the first working chamber (6
The shock absorber according to any one of claims 2 to 4, which communicates with 1). 6. The shock absorber as claimed in claim 5, wherein the connection (70) monitored by a check valve branches from the liquid chamber (32) in the region of the rod seal member (16). 7. The shock absorber according to claim 1, wherein the inner sealing point (18) is a gap packing. 8. The shock absorber according to claim 7, wherein the inner sealing member (18) serves for guiding the piston rod (4). 9. The shock absorber according to claim 1, wherein the movable separator (36) is a diaphragm. 10. The shock absorber according to claim 1, wherein the movable separator (36) is a separating piston. 11. The cylinder (2) is at least partially surrounded by a pipe (46), the intermediate chamber between the cylinder (2) and the pipe (46) being the compensation chamber (3).
0) forming a shock absorber according to any one of claims 1 to 10. 12. Compensation chamber (30) comprises at least one
2. One separate gas chamber (34a, 34b), said gas chamber being separated from said liquid chamber (32a, 32b) by a moveable separator (36a, 36b). The shock absorber according to any one of 1 to 11. 13. At least one of the gas chambers (34a, 34b) is separated by a diaphragm (36a) and at least one of the gas chambers (34a, 34b) is separated by a separation piston (36b). The shock absorber according to claim 12, which is provided.