JP3025238B2 - Lockable piston / cylinder unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a piston-cylinder unit according to the preamble of claim 1.

[0002]

2. Description of the Related Art German Patent Application No. 43 326 968 discloses a fixture for fixing objects which can move relative to one another. Such a fixing device is, for example, a vehicle door for getting on and off a person.
Used for (Fahrzeugtuer) or flaps (Klappe) (eg doors like glove box lids). These, on the one hand, need to be easily operable, but need to reliably support the loads that occur. An advantage of the fixing device shown in DE-A 43 26 968 is that the holding function is possible independent of the stroke. Other unit types allow the holding function only in a defined open area of the vehicle door or flap, or only in a fixedly defined locking stage.

[0003] The problem with a steplessly lockable unit is that there is a perceivable squeal which is not provided in this manner in prior embodiments with a predetermined locking position and is a lack of comfort. It is in.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to configure a piston-cylinder unit in such a way that the noise problems known from the prior art are solved.
Furthermore, it is another object that the operating force is as constant as possible.

[0005]

The present invention SUMMARY OF THE INVENTION The problem is, the flow path between the shut-off valve, a first one of the shut-off valve
From the outflow side of the stop valve in the direction of flow through the stop valve
This problem is solved by arranging a throttle device having a pressure reduction portion between the first shut-off valve and the second shut-off valve on the valve inflow side. In doing so, the throttle device becomes weaker with an increasing degree of opening of the first closing valve , and the subsequent biasing of the second closing valve increases to the same extent on the valve inlet side. Proper adjustment of the dynamic pressure between the shut-off valves is made so that there are no pressure peaks, which also lead to violent valve movements which sound unpleasant as noise.

[0006]

In another embodiment, the first shut-off valve is a second shut-off valve .
It has one valve closing body. Also, the second stop valve is the second valve
It has a closure. The first valve closing body contacts the support surface (holding surface) of the slider (Schieber) in the opening direction. The slider is also in operative connection with the second valve closing body. As a result, the opening movement of the first valve closing body is transmitted to the second valve closing body. In practice, closed
The stop valves are also mechanically arranged in series. Because they open in the same direction each time.
For that reason, it is advantageous for the second shut-off valve to be provided with a region that is not extended somewhat (sealed region). As a result, the entire valve arrangement is less sensitive to length tolerances in its operating behavior.

[0007] It is therefore advantageous that a throttle device is connected downstream of the second shut-off valve on the outlet side. Controlled decompression (Druckabbau) is performed,
It minimizes possible noise. This is also due to the second characteristic having a 0/1 characteristic curve.
This is because there is no sudden opening of the closing valve .

It is taken into account that the first valve closing body is formed by a valve ring which is arranged axially movably on the valve sleeve. The valve ring is a slide valve in its function. A completely ordinary O-ring may be inserted as the valve ring.

In addition, a throttle device in which the valve sleeve is effective depending on the path (displacement) (the throttle device referred to here )
The device is arranged so that the valve of the second shut-off valve is arranged from the valve outlet side of the first shut-off valve.
Such a throttle having a pressure drop between the inlet side
Device) . The throttle device is controlled by a valve closing body. In this case, the throttle device is defined by at least one groove in the valve sleeve between the first stop valve and the subsequent second stop valve. Multiple grooves of different lengths may be incorporated. As a result, continuous decompression can be performed.

[0010] In view of the universal availability of the piston-cylinder unit (piston-cylinder assembly), the valve device is designed to have two flow directions and to be respectively lockable. ing.
Consider a vehicle whose tailgate must always be open due to the overhanging load. Due to the blocking function in both directions, additional protective measures (Sicherungsmassn
ahme) is not required. In this case, the first shut-off valve is also used for both flow directions.

In order to limit assembly costs, the piston is designed as a tube, on which at least one of the sliders is arranged. In this case, a lid is fixed to at least one end of the tube. As a result, the piston is a pre-assembled structural unit. The slider guided inside the tube is not exposed to lateral forces due to mechanical loads. As a result, motion with less friction is possible.

Preferably, the second valve closing body of the second closing valve is formed as a radially elastic ring. It works in cooperation with a cylindrical valve seat provided on the slider . At this time, the cylinder-shaped valve seat surface for the shut-off switching position is provided on the slider.
Different valve seat surface for the open, open switching position. Thus, the valve closure member is mounted so as to float in the axial direction, and they depend on forces acting
Is moved between the valve seat surfaces.

To ensure unobstructed movement of the slider, the slider of the second shut-off valve is connected to the first shut-off valve and the second shut-off valve .
It is moved in a fluid communication (Fluidenverbindung) between the two shut-off valves. Thereby, the flow communication part changes in its size. In this case, the flow communication part has at least one pressure balance communication part switched by a check valve.

Therefore, the second valve closing body is controlled by the axial movability of the valve closing body, whereby the flow communication (Stroemungsverbindung) between the adjacent working chamber and the flow communication is controlled. Form a check valve for the flow communication. Therefore, an unintended negative pressure in the flow communication portion cannot occur.

[0015] In addition, the piston may have a piston ring separating the two working chambers from each other. that time,
The piston ring is elastically configured and partially deformable in the transverse direction. Thereby, the dynamic pressure communication between the flow communication part and the working chamber is controlled by a relatively slight instantaneous pressure. Thereby, the dynamic pressure in the flow communication part can also be reduced in accordance with the purpose so as not to hinder the slider movement in the running direction (retracting direction) into the flow communication part.

In a structural embodiment, the piston ring is guided by a piston ring groove having a pocket in the region of the dynamic pressure communication. A piston ring may move into the pocket. The piston ring is reliably guided in the piston ring groove. In so doing, the pockets limit lateral deformation, thereby sealing and eliminating material fatigue.

In the case of a lockable piston-cylinder unit, it may be necessary to consider what consequences will be obtained if the locking cannot be overcome, for example in the event of an accident. In the case of vehicle tailgates or front flaps, no special risk factors need to be taken into account. On the contrary, if the side door is equipped with a piston-cylinder unit according to the invention, there is a particular advantage if the piston is fixed to the piston rod by at least one holding element. At that time, the holding element is normally operated with a normal operating force (Norma
It is released when a higher force is applied, and the locking effect of the valve device is eliminated .

It is completely advantageous if the piston is fixed to the piston rod by two holding elements. In this case, one holding element has a greater holding force than the other holding element. Therefore, in order to be able to open the vehicle door with a noticeable amount of power in the event of an accident, the retaining element which receives the locking force of the piston attached to the piston rod in the opening direction of the door is more than the other retaining element. It may be taken into account that it is weakly configured.

In another advantageous embodiment, from a predetermined stroke position, the damping device influences the stroke movement of the piston-cylinder unit. A stopper or the like is no longer indispensable outside the unit. The damping is generated by mechanical and hydraulic (hydromechanical) pressure stops (compression stops, compression buffers).

Furthermore, it is to be taken into account that the damping device suppresses the speed of the stroke movement and that the closing valve, which is open during the stroke movement, occupies the closed position, thereby locking the piston-cylinder unit. Can be inserted. Thus, not only is damping achieved, but also the switching position (Schaltste) of the valve without the use of expensive electronic equipment.
llung) is affected.

In order to prevent the springing of the door or of another device, the pressure stop has a pressure stop spring with a maximum prestressing force which is less than the operating force required to overcome the locking of the valve device. .

In order to achieve the most accurate damping force possible, the pressure stop, except for the damping cross section, is hydraulically closed during damping operation by packing. Furthermore, it is taken into account according to the invention that the valve ring is designed to be compressible in the axial direction (crushable) and elastically in the radial direction.
As a result, the axial compression (crushing) of the valve ring caused by the operating pressure causes an increased radial prestress in the area of the sealing surface, wherein the maximum prestress of the valve ring is elastic. Limited by body reaction. The frictional force of the valve ring acts against the operating force. Therefore, the change in the friction force is also a change in the operation force. The working pressure and the friction force also act in opposite directions. In this case, the increased operating pressure assists the operating force and, on the other hand, supports the sealing action. The working pressure, frictional force and sealing action are directly related. The maximum frictional force is limited by the elastic. because,
This is because the elastic force supports the valve ring and thereby acts against the operating pressure. By the use of a special sliding material (Gleitwerkstoff) such as, for example, PTFE, a reliable seal is achieved at the inner and outer diameters of the valve ring without direct radial prestressing means.

An elastic element having a spring constant smaller than the spring constant of the closing elastic body is provided on the rear side of the valve ring so that the prestress on the valve ring can be configured to be relatively independent of the force of the closing elastic body. Is added. The force of the closing elastic body determines, for example, the holding force of the piston / cylinder unit. Thereby, the prestressing of the valve ring will also affect the holding power of the piston-cylinder unit. However, this is disadvantageous in some cases.

The elastic element has an arch-shaped (arc-shaped) space shape in consideration of a structural shape that does not take up any special space, and is thereby a kind of disc spring. The elastic element is provided with an opening, for example a slit, in at least one location so that it is not possible to enclose the volume between the elastic element and the support surface of the slider. As a result, the front side and the rear side of the valve ring communicate with each other.

In one embodiment, at least two valve rings are arranged in series. These valve rings seal only by one of their diameters forming a ring shape, and the respective ring-shaped surface of each of the valve rings is biased by the operating pressure. The existing gap can additionally be used for thermal expansion compensation.

Another type is distinguished by the fact that the valve ring has a circumferentially extending groove in one of the surfaces closing the leak. This results in different resilient areas in the valve ring. Thus, the groove has a width in relation to the thickness of the valve ring, resulting in at least one resilient sealing lip. The groove extends toward the sealing lip. The operating pressure acts on one of the sealing lips in the direction of flow (Anstroemrichtung) and causes a corresponding prestress. In addition, a sealing lip on the other side of the groove is raised during the movement of the valve ring,
This gives a relatively strong prestress to the entire valve ring.

In a further advantageous embodiment, it is provided that the valve ring is alternately drawn from two directions and is pressure-energized. The valve ring is configured in a mirror image so that assembly independent of the direction of the valve ring can be eliminated.

In one embodiment, the valve ring has an essentially concave surface shape in the flowing direction. As a result, the valve ring has a surface that can be biased toward the surface to be sealed. Independently or in combination therewith, the support surface may have at least one surface area oriented towards the surface to be closed by the valve ring on the slider. This surface area acts like a wedge (Spannkeil) on the surface of the valve ring.

Independent of the various cross-sectional shapes of the valve ring, it is advantageous if the valve ring has at least one surrounding groove. The groove defines a free space used for thermal expansion compensation.

【Example】

The present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram illustrating an example of an attachment state. 2-9 are cross-sectional views of various embodiments of the present invention. FIG. 10 is a schematic overall view of a piston / cylinder unit. FIG. 11 is a schematic view of an installation state in the case of a side vehicle door. FIG. 12 is a schematic view of a piston / cylinder unit having a damping device. FIG.
FIG. 18 is a schematic illustration of various embodiments of a valve ring that may be pre-stressed.

FIG. 1 shows a stylized motor vehicle 1 having a vehicle tailgate (Fahrzeugheck klappe) 3 movably arranged around a pivot axis 5 oriented transversely to the longitudinal axis of the vehicle. Shown. A piston / cylinder unit 7 is movably pivotally connected between the vehicle body and the vehicle tailgate via a coupling mechanism 9; 11 to assist the opening movement. The piston-cylinder unit has a cylinder 13 and a piston rod 15 which can move axially therein. At this time, one member engages with the vehicle body and one member engages with the vehicle tailgate. As a result, the motion of the vehicle tailgate proceeds in synchronization with the running (retracting) and running (extending) motions of the piston rod. The use of piston and cylinder units is not limited to vehicle tailgates,
It can be diverted to other applications, such as vehicle doors.

A first embodiment is shown in FIGS. At this time, the illustration shows the piston / cylinder unit 7
Is limited to the part having the piston 17 attached to the piston rod 15. The piston 17 forms a casing for the valve device 19. The valve device includes a piston ring 1
Working chamber 23 separated by a piston having 7b;
The flow connection 21 between 25 can optionally be connected, allowing a stepless hydraulic locking of the piston-cylinder unit 7. For this purpose, the valve device has a first closing valve 27 with a valve closing body 29. The valve closing body is formed by a valve ring and is axially movably mounted on a valve sleeve 31 forming a part of a piston. At this time, the valve closing body contacts the support surface (holding surface) 33 of the slider 35. The slider is axially movably arranged on a guide sleeve 37 and is prestressed in the axial direction by a closing spring 39. On the other hand, the closing spring is supported by the lid 41. The lid forms the casing together with the piston. The valve device is constructed in a mirror image (mirror image object) with respect to the first valve closing body 29, and as a result, a shutoff function (lock function) in both flow directions of the flow communication portion 21 is possible.

FIG. 2 shows the valve device in the locked position.
The valve closing body 29 of the first closing valve 27 is in the sealing area 43 in the central part of the valve sleeve 31. Starting from the sealing surface area, a throttle device 45 connects to the outlet side of the first shut-off valve 27. In order to release a larger flow-through cross-section as the adjustment path (adjustment displacement) of the valve closing body 29 increases, the throttle device comprises several grooves 45 'of different lengths. FIG. 4 shows the tube 17a of the piston as a part, which allows the groove 45 'to be recognized.

The valve device 19 has two shut-off valves 27; 47 or 27; 47 'arranged in series.
In this case, the second shut-off valve 47; 47 'is only opened when the first shut-off valve has already been switched to the durable state. The second closing valve 47; 47 'is also a valve closing body 49; 4 configured as an elastic ring-shaped body.
It has 9 '. The elastic ring-shaped body is tightly fixed to the cylindrical valve seat surface 51; 51 ', and the slider 3 of the second closing valve 47;
5; 35 'can be supported on the flange 53; 53'.

The cylindrical valve seat surface 51; 51 'has another valve seat surface 55; 55' of smaller diameter on the side opposite the flange. The other valve seat surface is formed in a tapered shape. Thereby, the flange 5
3: There is no need for the step to be overcome during axial movement from the direction 53 '.

A throttle device is also connected downstream of the second shut-off valve on the outflow side. The throttle device comprises a slit 57; 57 'in the tube 17a of the piston. This prevents the complete dynamic pressure acting on the first shut-off valve from flowing undisturbed through the second shut-off valve 47; 47 'and causing noise.

In the valve device 19, for reasons of operating comfort,
The valve operating force (Ventilausloesekraft) divided into stages is input. For this purpose, both shut-off valves 27; 47; 4
7 'are provided with differently sized pressure biased surfaces. For the first shut-off valve 27, the pressure-biased surface should be made equal to the area of the valve ring, hereinafter referred to as A _Ring . The second shut-off valve 47; 47 'has a much larger pressure-biasable surface. This surface results from a ring of sliders 35; 35 'with valve _closures 49; 49', hereinafter referred to as A _Schieber . Surface A
_Schieber is obviously bigger. As a result, the effective opening force (opening force, Offenhaltu
ngskraefte) is many times greater than the operating force at the first shut-off valve. At that time, the operating force only needs to be procured for a short moment, at which time comfortable use exists.

In FIG. 3, the movement of the piston rod 15 in the direction of the arrow to the left has been accepted. Left working room 23
Is forced to increase. Through an opening 59 'in the lid 41' on the left side of the piston, medium, usually oil, can flow from the working chamber 23 into the piston, with the second closing valve 4 on the left side.
7 'acts on the slider 35' in the closing direction. The stopper 61 'restricts the running movement of the slider on the piston. The slider 35 'has a flow recess 63' on the side of the valve ring that allows the medium to reach the valve ring. The valve ring is pushed out of the valve seat surface 51 'by pressure. Thereby, the medium is transferred to the first valve closing body 29.
The gap 65 'to be hit is released. Closing spring 39
A dynamic pressure is generated on the surface A _Ring to move the slider 35 together with the valve closing body 29 toward the working chamber 25 against the force of the above. As soon as the first valve closing body 29 leaves its starting position, the medium can flow into the flow communication 21 via the throttle device formed by the different length grooves 45 '. In this case, a significant pressure difference is generated, so that the second valve closing body 49 is urged with a relatively small dynamic pressure.

The dynamic pressure on the surface A _Schieber in the flow communication 21 moves the slider 35 further right until the second valve closing body 49 reaches the area of another throttle device formed by the slit 57. Based on the large surface A _Schieber , relatively low dynamic pressure is sufficient to keep the slider open during piston rod movement.
As a result, the operating force on the flap is small.

As soon as the piston rod 15 stops relative to the cylinder 13, no dynamic pressure is applied to the first and second shut-off valves. A pressure balance occurs in which the slider 35 of the second closing valve 47 is again moved to its starting position based on the elastic force of the closing spring 39. The slider movement of the first closing valve 27 towards the sealing surface area 43 causes the first valve closing body 29 to be moved into the sealing surface area 43 by the support surface 33 of the slider 35. As a result, the first shut-off valve 27 occupies its shut-off position. Thereby, the entire valve device 19 is in a shut-off state.

In the case of a reverse piston rod movement in which the working chamber 25 is reduced, the flow into the piston 17 takes place precisely as already described. The valve ring sits on the sealing surface 43 and also serves as a first valve closure in this direction of flow. However, differently, the left second shut-off valve 4
The gap 65 'described in the middle at 7' is present due to the reverse flow direction from the working chamber 23. However, the gap is already closed by the valve closing body 49 'of the second closing valve 47' when the first closing valve 27 flows slightly, and the second valve closing body 49 is closed by the valve seat surface. 51 '.

FIGS. 5 and 6 show a valve device 19 having a functional principle according to FIGS. Accordingly, the two shut-off valves 27; 47 are similarly controlled in series. At this time, the surface A _Schieber capable of energizing the pressure with different dynamic pressures is _used.
And A _Ring .

The difference from FIGS. 2 and 3 is that the slider 35; 35 'is directly connected to the pin (shaft, Zapf) of the piston rod 15.
en). Furthermore, the valve closing bodies 49; 49 'of the respective second closing valves have only one but extended valve seat surface 51. As a result, the valve closing body is no longer deformed in the radial direction.

A fundamental problem with sliders exists whenever they are pushed into one cavity or moved out of it. It is necessary to prevent the generation of dynamic pressure or negative pressure that hinders the slider movement. For that reason, the valve device 19 has a check valve 67; 67 'for connecting or shutting off the pressure balance communication 69, 69'. The check valve is formed by a piston ring 17b of the piston, which hydraulically separates both working chambers 23; 25. The piston ring is guided in the piston ring groove 71. The piston ring groove has pockets 73; 73 '. A pressure balance communication part 69; 69 'is provided in the pocket.
Is open. The pocket is fitted in the groove side wall, so that the elastically configured piston ring is deformed into one or more pockets by a correspondingly acting frictional force between the cylinder and the piston ring. And thereby the pressure balance communication 69; 6
Open or close one of the 9's.

Another measure to prevent negative pressure in the flow passage 21 is that the extended valve seat surface 51; 51 'of each second shut-off valve 47; 47' has at least one passage (recess). , Einstich) 75; 75 '. As a result, the valve closing body 49;
5; When it is covered (wrapped) by 75 ',
No action is taken to block complete leakage.

FIG. 5 shows the valve device 19 in a stationary state. The same operating pressure prevails in both working chambers 23; 25. The first stop valve 27 is in a closed state,
The second shut-off valves 47; 47 'also do not allow the passage of medium. Further, the piston ring 17b is located in the piston ring groove 71 consistently and uniformly in the circumferential direction.

In FIG. 6, the piston rod is moved to the left
Moved toward. This increases the pressure in the work chamber. The medium under pressure flows into the valve device via an opening 59 'in the lid 41'. The left slider 35 'is moved by its stopper 61' on the basis of the effective dynamic pressure and the elastic force of the closing spring 39 '.
7a. Only a small leak is caused by the valve closing body groove 7
It is possible to enter the inside of 7 ', and the valve closing body 49 is brought into contact with the back surface of the stopper 61'. However, the position of the valve closure is not important for this direction of flow.

The movement of the piston rod makes available the frictional force between the inner diameter of the cylinder 13 and the piston ring 17b which elastically deforms the piston ring in the region of the pocket 73. Thereby, the pressure balance communication part 69 is closed by the piston ring.

The medium flowing in is diverted towards the inner diameter of the slider 35 'and transferred by the vertical duct 79' (see FIG. 6) to the first shut-off valve 27. The slider 35 'is provided so that the closing body occupies a predetermined operating position.
End face 33 ′ of first closing valve 27 facing closing body 29.
Are formed diagonally, but on the other side there is a ring-shaped chamber 81 'in which a dynamic pressure can be generated which can move the valve closing body 29 of the first closing valve 27 in the axial direction. .

During the displacement movement of the first valve closing body 27, it moves out of the sealing surface area 43. as a result,
Media can enter. In this case, grooves 45 'of different length form a throttle device for reducing pressure (relaxation of pressure) beyond the sealing surface area. Nevertheless, a dynamic pressure is generated in the flow communication part 21. at the same time,
Due to the direct contact with the slider 35, they move together in synchronization. The valve closing body 4 of the right second closing valve 47
9 is under prestress on the inner diameter of the tube 17a. Thereby, there is a permanent frictional coupling. In this movement phase of the second shut-off valve 47, the valve closing body 49 of the second shut-off valve is kept on the valve seat surface 51 by frictional force in the area of the passage 75. Exceptional media volumes can enter. At that time, the pressure is reduced in the same manner. Despite the intrusion of the medium amount, a dynamic pressure can be generated in the flow communication portion 21. At that time, the surface A _Ring and A already same principles as described for FIGS. 2 and 3 are biased pressure
_{Used for Schieber} .

The dynamic pressure in the flow communication part 21 causes the slider to move the valve closing body 49 further toward the working chamber 25. The passage 75 in the valve seat surface 51 is no longer provided in this movement phase. This is because the valve closing body 49 of the second closing valve occupies its illustrated position. However, during that time, the slider is
In the area of the slit 57, the slit enables the narrowed medium to enter. Relatively little dynamic pressure holds the slider in the open position. The gradual decompression does not cause any noise at first.

As soon as the piston rod movement is interrupted, it is desired that a pressure balance between the working chambers 23; 25 occurs. The elastic deformation of the piston ring 17b causes it to move back to its relaxed position. Thereby, the pressure balance communication part 69 is released again. Now, an inevitable gap 83 between the flow communication part 21 and the pressure balance communication part 69, the pipe 17a and the cylinder 13 is provided.
There is direct communication between the working chamber 25 via As a result, a pressure balance between the flow communication portion 21 and the working chamber 25 may also occur. Thus, the slider 35 can certainly be pushed back to its starting position by the closing spring 39.

Since both sliders 35; 35 'are constructed identically, the lock in response to the piston movement in the opposite direction is, as already mentioned, locked on the left second shut-off valve 4.
Can be strictly followed by 7 '(ie, can be performed similarly). However, different elastic forces in the closing springs 39; 39 'may be taken into account in order to adapt the necessary dynamic pressure to the requirements.

FIGS. 7 and 8 are likewise variants of FIGS. 5 and 6. The essential functional difference between the variants of both FIGS. 5 and 6 and FIGS. 7 and 8 is that the valve closing bodies 49; 49 'of the respective second closing valves 47; 47' are ring-shaped. It is not necessary or possible to carry out any axial or radial movement in the groove 85; 85 '. As an alternative to the function "prevention of negative pressure in the flow communication part 21", a check valve constituted by the slider 35;
9; another pressure balance communication 87 having the form 89 ';
87 'is used. The tilting disc is switched by pressure bias between two limited stops on the slider.

In the rest position (fixed position) shown in FIG. 7, the first shut-off valve 27 and both second shut-off valves 47; 47 'and the tilting disc between the flow communication part 21 and the working chamber 23; 89; the check valve with 89 'is closed. The first pressure balance connection 69; 69 'switched (connected) by the piston ring is open.

In the piston rod movement in the direction of the arrow, the medium mostly flows into the slider 35 ′ formed in the shape of a pot and reaches the first shut-off valve 29. However, at the same time a relatively small part of the medium is
3, and also flows to the piston ring 17b, via the pressure balance communication 69 'to a check valve having a tilting disc 89' for another pressure balance communication 87 '. Due to the differently sized pressure-biasable surfaces of this check valve, it is held in a closed position. Whether the check valve in the left slider 35 ′ is open or closed is insignificant for the function of the second stop valve 47 on the right.

By the piston rod movement, the pressure balance communicating portion 69 is isolated from the working chamber 25 by the blocking state of the piston ring 17b in the pocket 73 of the piston ring groove. When the first shut-off valve 27 opens, the pipe 1
The medium flowing into the flow communication portion 21 via the groove 45 'in 7a can generate a second smaller dynamic pressure in the second shut-off valve 47. No special leakage loss occurs. The dynamic pressure effective on the pressure- _energized surface A _{Schieber causes} the slider 35 to resist the force of the closing spring 39 and cooperate with the valve closing body 49,
It is moved to the area of the slit 57. Thereby, the second stop valve 47 is also opened. In this case, a new decompression takes place by means of a slit configured as a throttle device, in order to avoid any sudden changes in pressure (Druckspruenge) and therefore noise.

At the beginning of the opening movement of the first and second closing valves 27 and 47, a situation arises as can be seen in FIG. The piston ring 17 b blocks the pressure reducing communication part (pressure release communication part) 69, and the first closing valve 27
At the moment when the valve closing body 29 has not yet reached the groove 45 behind the valve sealing area 43, a negative pressure will occur in the flow communication 21. This negative pressure will be detrimental to the opening behavior of the second shut-off valve 47. For that reason, the non-return valve 87; 89 of another pressure balance communication 89 opens at this moment, allowing the medium to flow from the working chamber 25 into the flow communication 21. As soon as the first shut-off valve 27 allows the medium to enter (medium overflow), the dynamic pressure in the flow communication part 21 closes the check valves 87 and 89 again.

If the piston rod is no longer displaced, the dynamic pressure on the second shut-off valve 47 will also drop until the force of the closing spring 39 is greater than the opening force of the dynamic pressure. In this operating state, the valve arrangement behaves exactly as described for FIGS. At this time, the second pressure reducing communication section 8
9 are closed, whereas the first pressure relief communication 69 with the check valve formed by the piston ring is open. as a result,
The slider can be controlled into the flow communication section 21 until the rest position is occupied again.

FIG. 10 is a sectional view showing the entire piston / cylinder unit 7. The valve device corresponds to the configuration shown in FIGS. The preceding description has always started because the locking function is effective for all stroke lengths of the piston-cylinder unit. However, there are applications where the lock function in a given area is not used with a very high probability. To this end, the cylinder has at least one bypass groove 91 or an enlarged diameter part. It allows communication between the two work chambers 23; 25 independently of the operating position of the valve device 19.

As already mentioned in FIGS. 2 and 3, the entire piston 17 can be pre-assembled with its internal parts independently of the piston rod 15 as a structural unit. The fixing of the piston is achieved by a ring-shaped holding element 9.
3:95. Said retaining elements are brought into the region of the piston rod 15 in each case a groove 97; The piston is aligned between both grooves in the piston rod. If the desired position of the piston is occupied, both holding elements are pressed into the respective groove and the form-locking connection.
As a result, the axial position of the piston is fixed.

It has to be taken into account that, for example, in the event of an accident, the locking function of the valve device should not be unlocked for reasons that are not obvious. For that reason, when the flap has to be opened, for example, the holding element 95, which takes on the support, is torn off when a detachment force (Losreisskraft) is introduced which acts more than an acceptable operating force. In this particular embodiment, it is a holding element 95 between the piston 17 and the separating piston 101.

In FIG. 10, the separation piston 101 is prestressed by a coil compression spring 103.
However, the space 105 between the separating piston and the bottom 107 of the piston-cylinder unit is prestressed by the compressed gas, so that the working pressure which moves the piston rod in the running direction acts on the end face of the piston rod. Then it is quite significant. .

FIG. 11 shows, for example, the state of attachment of the piston / cylinder unit 7 at the lateral vehicle door 3a connected to the front column (A pillar) of the motor vehicle 1. In this application, the locking function is undertaken by the piston-cylinder unit. Unlike the application shown in FIG. 1, the vertical acting weight of the vehicle door is less critical in operation. This is because the hinge takes on the mounting (bearing) of the door. With regard to the opening force, it has the consequence that the door can accept a relatively high movement speed with a corresponding swing. This is because only the frictional force at the bearing and the inertia force (moment of inertia) of the vehicle door must be overcome.
In the closing direction, the mechanical load is less important. Because the hinge 109 and the center pillar (B pillar)
This is because the lock portion (not shown) can absorb the force.

In the opening direction, the same situation looks distinctly different. Only the hinges will have to hold the door 3a and absorb the forces. In this case, not only does the weight act downwards, but also the inertial force of the vehicle door is much more important for the load on the hinges and especially on their joints in the vehicle body. The simplest possibility of reliably absorbing the inertial forces is to raise the vehicle body clearly at the joint. However, it will need to accept the weight gain. In so doing, structural space is barely sufficient for such measures.

FIG. 12 shows a piston / cylinder unit 7 shown in FIG. 10 having a piston corresponding to FIGS.
FIG. At that time, the modified example may be similar to another described one.

The piston / cylinder unit 7 has a mechanical / hydraulic (hydromechanical) pressure stopper (Druckanschlag) 111. The pressure stopper has a stopper sleeve 113 supported by the piston rod guide unit 117 via a pressure stopper spring 115.

The stopper sleeve has a surrounding flange 119. A packing ring (seal ring) 121 is fitted into the flange.
The packing ring seals a gap between the stopper sleeve 113 and the cylinder 13. The inner wall portion of the stopper sleeve is configured with a step. At this time, the step surface 123 is located at the point of insertion of the pressure stopper 111 (Ein
from the contact surface 125 of the holding element 93.

Step surface 12 from the inlet side of the stopper sleeve
The diameter of the steps up to 3 is determined in such a way that no particular restriction occurs compared to the diameter of the holding element 93. The actual stop is the damping aperture 1 in the stopper sleeve.
27. This damping opening allows the rear side of the stopper sleeve to communicate with the inflow side of the piston 17.

The illustration in FIG. 12 is compressed for the entire length of the piston-cylinder unit. Of course, the pressure stopper does not directly hit the bypass groove 91. The interval between the bypass groove and the insertion point of the pressure stopper,
It can be adapted to the occasional use situation.

In the piston rod movement in which the working chamber 23 is reduced, the holding element 93 moves at a substantially constant speed from a predetermined stroke position into the stepped inner wall. The medium (usually a hydraulic fluid, as already mentioned) in the working chamber 23 is a valve 27 with an open piston.
47. End face 12 of holding element 93
As soon as 5 abuts against the stepped surface 123, the damping opening 127
, A damping force for lowering the speed of the piston is generated. The end face 125 and the step face then form at least a dynamically effective seal. As a result, the damping effect is determined solely by the cross section of the damping opening in a manner that meets the purpose.

[0072] Further, fluid may flow into the piston. This is because there is still an interval between the lid 41 ′ and the stopper sleeve 113 at the point of attachment of the pressure stopper 111.

With a decrease in the speed of movement of the piston, the flow velocity of the fluid is also reduced by the piston and therefore by the dynamic pressure at the valves 27,47. If the dynamic pressure is below the threshold, the valves 27 and 47 are locked (see FIG. 7).
Move to Forcibly, the piston, piston rod, and thereby the vehicle door are also stuck. At this time, the entire process is not abrupt but progresses continuously due to the damping action of the damping opening, and the force introduction to the vehicle body occupies a level that can be reliably controlled. Valve 27 in the shut-off position (lock position);
47 'also prevents the possibility of the vehicle door bouncing. In this connection, the elastic force of the pressure stopper spring 115 can cause the pressure stopper to be moved back to the starting position against the frictional force between the packing 121 and the cylinder 13,
However, it has to be ascertained that it is so small that it cannot exert a forcing force on the piston rod.

In the following examples, various valve rings 2
9 will be described. For the overall function of the valve device, see FIG.
See the description of the figures for FIGS. In FIG.
The valve closing body or valve ring 29 is used for both sliders 3
5; 35 'and a closing spring 39 for urging the same;
Are tightened between. Stopper 61; 61 '
Is not effective in the closed valve position, so that the prestress of the valve ring depends only on the elastic force of the closing spring 39; 39 '. The valve ring is made of a compressible (crushable) radially resilient material having a relatively low coefficient of friction. The valve ring is squashed with increasing pressure bias due to the medium flowing through the vertical duct 79; 79 '. In this case, the pressure rises very quickly, so that radial expansion occurs in parallel. Valve ring compression capacity (Stauchfaehigk
eit) should be evaluated as a spring constant acting in series with the spring constant of each closing spring. Due to the effective reconciliation of the compression capacity of the valve ring to the spring constant of the closing spring, before the maximum radial spread (expansion) and thus the standard force on the sealing surface exists, only a small amount in the opening direction of the valve ring It can be achieved that a good exercise progresses. However, in a movement that is already in progress, there is sliding friction. As a result, there is a low level of friction which is known to reduce comfort when using the piston-cylinder unit.

The valve ring is designed in a mirror image, so that it can be mounted without fear of being mistaken. 14A and 14B show another cross-sectional shape of the valve ring 29. FIG. In this case, their cross-sectional shape is such that at least one groove 29 for compensating the thermal expansion of the valve ring is provided.
a. By the way, the use of the groove 29a achieves an essentially linear contact between the valve ring 29 and the sealing surface area 43.

In the modification shown in FIG. 15A, the slider 3
5; 35 'of the bearing surface 33; 33' is a surface area 33 oriented in the direction of the surface to be cleared by the valve ring
a; 33a '. These surface areas 33a; 3
3a 'acts on the valve ring 29 like a tightening wedge (Spannkeile) and enhances the radial deformation of the valve ring 29.

FIG. 15B shows a modification in which this effect is further enhanced. The valve ring has a concave surface profile in the area of the pressure-biased surface in its relaxed mounting position. The support surfaces 33; 33 'have correspondingly corresponding contours. On one side of the valve ring 29, pressure acts on the concave surface profile, whereby the sealing lip 29b; 29b 'generated gives a stronger prestress. On the contact side of the valve ring in one of the sliders 35; 35 ', the bearing surface 33; 33' acts like a wedge by means of a surface area 33a; 33a 'directed to it.

In FIGS. 16A and 16B, the stopper 6
1: a valve device is used to determine the slider position with 61 'closed. The valve ring 29 can be displaced only slightly axially in the sealing area 43 when the valve is closed.

The configuration shown in FIG. 16A has at least two closing members which close and contact the inner diameter portion or the outer diameter portion.
Check valve body 29c, 29d; consisting 29c. As soon as the medium hits one of the closing valve bodies 29c; 29d through the vertical duct 79; 79 ', the entire packet is transferred to the slider 35;
35 'is shifted towards the current support surface 33; 33'. At this time, the operating pressure acts on the ring-shaped surface 29e of the closing valve body 29c and on the inner diameter portion 29f. As a result, these closure valves are axially and radially compressed and prestressed. One for each
A valve packet with closing valves 29c and 29d would be sufficient. However, it cannot be ruled out that the basic prestresses of the two closing valves differ from each other and that an axial gap between the two closing valves as they flow in.

The embodiment shown in FIG. 16B shows a valve ring 29 having a deeper groove 29a compared to the configuration shown in FIGS. 14A and 14B. The valve ring is configured undersized (Untermass) with respect to the piston rod 15. As a result, the sealing lip 29b;
b '. Valve ring 29 from the direction of the vertical duct 79 '
In the case of the exemplary bulging, the sealing lip 29b '
Are more strongly prestressed radially inward.
At the same time, the axially movable valve ring 29 is displaced to the right. The frictional force between the sealing lip 29b and the piston rod 15 causes the sealing lip to move toward the groove 29a. This causes a radial prestress of the valve ring.

In FIGS. 17 and 18, the stoppers 61; 61 'are again effective for determining the slider position in the closed valve position. Unlike FIGS. 16A and 16B, the free space between the support surfaces 33; 33 'is filled by elastic elements 29g and 29g'.
Thereby, the axial prestress of the valve ring 29 is determined primarily by the elastic modulus (spring constant) of the elastic elements 29g; 29g '. The elastic element does not block the leak at the inner diameter portion and does not block the leak at the outer diameter portion. An unillustrated cut-out (Einschnitte) connects the front side of the respective elastic element with the rear side in such a way that undefined encapsulation of the medium never occurs.

The modification shown in FIG. 18 is different from the modification shown in FIG.
This corresponds to a modification of FIG. The difference is that the elastic elements 29g; 29g 'have an arched spatial shape, thereby providing the advantage of a small structural space compared to the variant shown in FIG. Further, the spring constant can be reduced.
In general, the introduction of the elastic element is only meaningful when the spring constant of the elastic element is smaller than the spring constant of the closing spring 39; 39 '.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of an attachment state.

FIG. 2 is a schematic cross-sectional view of one embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of the embodiment shown in FIG. 2 in another state.

FIG. 4 is a view of a tube of a piston as a part. A cross-sectional view is shown on the left side, and a view of the end face is shown on the right side.

FIG. 5 is a schematic sectional view of another embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view of the embodiment shown in FIG. 5 in another state.

FIG. 7 is a schematic sectional view of another embodiment of the present invention.

FIG. 8 is a schematic sectional view of the embodiment shown in FIG. 7 in another state.

FIG. 9 is a schematic sectional view of the embodiment shown in FIG. 7 in still another state.

FIG. 10 is an overall view of a piston / cylinder unit.

FIG. 11 is a diagram showing an example of a mounting situation in the case of a vehicle door on the side.

FIG. 12 is a diagram of a piston-cylinder unit having a damping device.

FIG. 13 is an illustration of an embodiment of a valve ring that can be prestressed.

FIG. 14 is an illustration of another embodiment of a valve ring that can be pre-stressed.

FIG. 15 is an illustration of another embodiment of a valve ring that may be pre-stressed.

FIG. 16 is an illustration of another embodiment of a valve ring that may be pre-stressed.

FIG. 17 is an illustration of another embodiment of a valve ring that can be prestressed.

FIG. 18 is an illustration of another embodiment of a valve ring that may be pre-stressed.

[Explanation of symbols]

7 Piston / cylinder unit 15 Piston rod 17 Piston 17a Pipe 17b Piston ring 19 Valve device 21 Flow communication part 23, 25 Work chamber 27 First closing valve 29 Valve closing body 29a Groove 29b Sealing lip 29c; 29d Valve ring 29f Ring Surface 29g elastic element 31 valve sleeve 33 support surface 33a surface area 35; 35 'slider 39 closing spring 41; 41' lid 43 sealing surface area 45 'groove (throttle device) 47; 47' second closing valve 49 49 'valve closing body 51; 51' valve seat surface 55; 55 'valve seat surface 57 slit (throttle device) 69; 69' pressure balance communicating portion 71 piston ring groove 73; 73 'pocket 75; 75' passage (pressure) 87 ′ 87 ′ pressure balance communication section 89 89 'tilted disk 93; 95 holding element 111 pressure stopper 113 stopper sleeve 115 pressure stopper spring 117 the piston rod guide unit, attenuation cross section 121 packing ring 123 step surface 125 end face

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI F16F 9/52 F16F 9/52 (31) Priority claim number 19820404: 3 (32) Priority date May 7, 1998 (1998) .5.7) (33) Priority country Germany (DE) (72) Inventor Dirk Renecke, Germany Day 56626 an dernaach Zandweg 14 (72) Inventor Andreas Ritter Germany, Day 56206 Hill Gerd Hauptstrasse 11 (72) Inventor Marco Gehren DE 54570 Niederstadtfeld Hauptstrasse 5 (56) References JP-A-6-323356 (JP, A) JP-A-7-180422 (JP, A) JP Hei 10-19075 (JP, A) JP-A Hei 10-231876 (JP, A) JP-A-61-175636 (JP, U) German Patent Application Publication 4326968 (DE, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16F 9/00-9/58 B60J 5 / 04 B60J 5/10 E05C 17/30 E05F 3/04

Claims (34)

(57) [Claims] 1. A piston-cylinder unit having a cylinder divided into two working chambers by a piston attached to a piston rod, wherein there is a flow communication part between both working chambers, and the flow communication part is a valve device. In a piston-cylinder unit, wherein the valve arrangement has at least two shut-off valves arranged in series, each having a valve inlet side and a valve outlet side, which open in sequence. Device (19) having two flow directions and each
And the shut-off valves (27; 47; 4) in the respective flow directions.
7 '), a throttle device (45') is arranged in the flow path between the shut-off valve (2 ) and the throttle device (45 ').
7, 47; 47 ') and the valve outlet side of the first shut-off valve (27) and the shut-off valve (27, 47; 47').
A second closing following the first closing valve (27) in the flow-through direction;
Stop valve (47; 47 ') has a pressure relief portion between the valve inlet side, the throttle device before Symbol first shut-off valve (27)
Characterized in that it decreases in operation with increasing degree of opening of the second closing valve (47; 47 ') and to the same extent the pressure bias of the second closing valve (47; 47') increases on the valve inlet side.
Cylinder unit. Wherein said the first shut-off valve (27) is closed first valve closing body (29), said second shut-off valve (47;
47 ') has a second valve closure (49; 49').
If, and, said first valve closing body (29) is a slider in the opening direction; contact with the support surface (35 35 ') (33), wherein the slider is likewise the second valve closing body (4
9; 49 '), whereby the opening movement of the first valve closing body (29) is transmitted to the second valve closing body (49; 49'). The piston / cylinder unit according to claim 1. 3. The piston-cylinder unit according to claim 1, wherein a throttle device (57) is connected downstream of the second shut-off valve (47; 47 ') on the outlet side. 4. The valve closure according to claim 2, wherein the first valve closure is formed by a valve ring axially movably arranged in a valve sleeve. Piston and cylinder unit. 5. The valve sleeve according to claim 5, wherein the valve sleeve is provided in the first closed position.
Between the stop valve (27) and the second stop valve (47; 47 ').
The throttle device (4) disposed in the flow path between
5 ') and the throttle device (4
5 ') is characterized in that it is controlled by the dependent has potent and said first valve closing body displacement (29), piston-cylinder unit according to claim 4. 6. The throttle device (45 ') between said first shut-off valve (27) and said second shut-off valve (47; 47') in said valve sleeve (31). The piston / cylinder unit according to claim 4, characterized in that it is constituted by at least one groove (45 '). 7. The piston-cylinder unit according to claim 6, wherein a plurality of grooves (45 ') of different lengths are incorporated. 8. The piston-cylinder unit according to claim 1, wherein the first shut-off valve is used for both flow directions. 9. The piston (17) is a tubular body (17a).
And at least one slider (35; 35 ') is disposed on the tube, and a lid (41; 41') is fixed to at least one end of the tube. The piston according to claim 1, wherein the piston is a pre-assembled structural unit.
The piston / cylinder unit according to the item. 10. The second valve closing body (49; 49 ′) of the second closing valve (47; 47 ′) is configured as a radially elastic ring-shaped body, The body works in cooperation with a cylinder-shaped valve seat surface (51; 51 ') provided on the slider (35; 35') to block the light.
The cylindrical valve seat surface (51; 51 ') for the disconnected switching state is provided with the slider (35; 35').
Another valve seat for the open switching state (5
5. The piston-cylinder unit according to claim 2, characterized in that it has a different diameter from 5; 'The second valve closing body (49; 49; (47 47)' wherein said second shut-off valve is) is supported floating in the axial direction, the depending on the forces acting Cylinder
-Shaped valve seat surface (51; 51 ') and the other valve seat surface (5
5; 55 '), characterized in that it is moved between the piston-cylinder unit according to claim 10. 12. The slider (35; 35 ') of the second shut-off valve (47; 47') is connected to the first shut-off valve (27) and the second shut-off valve (47; 47 '). In the flow communication (21) during which the flow communication changes with respect to its size and the flow communication (21) is switched by a check valve (69) 69 ';75;75';87;
87 '). The piston and cylinder unit according to claim 2, wherein 13. The second valve closing body (49; 49 ′).
Working space (23; 2)
5) and the flow communication between the flow communication part (21) is controlled, whereby the second valve closing body (4) is controlled.
9; 49 ') is the pressure balance communicating portion (75; 7').
13. The piston-cylinder unit according to claim 12, characterized in that said check valve for 5 ') is formed. 14. The pressure balance communication part (87; 8).
Said check valve for 7 ') comprises a tilting disc (89; 8);
9 ') is formed by controlling the flow communication between the adjacent working chamber (23; 25) and the flow communication part (21) by its axial mobility. The piston / cylinder unit according to claim 12 . 15. The piston (17) has a piston ring (17b), which separates both working chambers (23; 25) from one another, said piston ring being elastically configured. And partially deformable in the transverse direction, whereby the flow communication part (2
1) and the pressure balance communication (6) between the working chamber (23; 25) having the lower instantaneous pressure.
9; 69 ') characterized in that it is child Control,
The piston / cylinder unit according to claim 12. 16. The piston ring (17b) is guided by a piston ring groove (71), and the piston ring groove is formed in a pocket (73; 73 ') in the area of the dynamic pressure communication part (69; 69'). The piston ring can move into the pocket.
The piston / cylinder unit according to the item. 17. The piston (17) is fixed to said piston rod ( 15 ) by at least one retaining element (93; 95), said retaining element being loosened upon introduction of a force higher than the standard operating force and The piston-cylinder unit according to claim 1, characterized in that the locking action of the valve device (19) is eliminated. 18. The piston rod ( 1 ) is provided by two holding elements (93; 95).
5 ) and one holding element (93)
18. The piston-cylinder unit according to claim 17, characterized in that the has a greater holding force than the other holding element. 19. A piston / cylinder unit (7) for which a damping device (113) is provided from a predetermined stroke position.
The piston / cylinder unit according to claim 1, wherein the piston / cylinder unit influences a stroke motion of the piston / cylinder. 20. The piston-cylinder unit according to claim 19, wherein the damping is generated by a hydromechanical pressure stop ( 111 ). 21. The damping device suppresses the speed of a stroke movement and a closed open during the stroke movement.
The stop valve (27; 47; 47 ') occupies the closed position,
20. The piston / cylinder unit according to claim 19, wherein the piston / cylinder unit is thereby locked. 22. The pressure stopper (111) having a pressure stopper elastic body (115) having a maximum prestress force less than the operating force necessary to overcome the shutoff of the valve device (19). Characterized by
The piston / cylinder unit according to claim 20. 23. Packing (121; 12) except that said pressure stopper (111) has a damping cross section (117).
21. The piston-cylinder unit according to claim 20, characterized in that the piston-cylinder unit does not receive hydraulic pressure during damping operation. 24. The first valve closing member (29),
It is formed by a grayed (29), and has the valve ring (29) is configured to be resilient to and radially as a compression capability in the axial direction, whereby,
The axial compression of the valve ring caused by the actuation pressure causes an increased radial prestress in the region of the sealing surface (43), the maximum prestress of said valve ring (29) being reduced by the elastic (29g, The piston / cylinder unit according to claim 2, wherein the piston / cylinder unit is limited by the reaction force of (39). 25. An elastic element (29g) is attached to the rear side of the valve ring (29), the elastic modulus of which is smaller than that of the closing elastic body (39). Item 25. The piston-cylinder unit according to item 24. 26. The elastic element according to claim 2, wherein the elastic element has an arcuate spatial shape.
6. The piston / cylinder unit according to 5. 27. at least two valve rings (29c;
29d) are arranged in series, they seal only by one of the diameters forming their ring shape, and the ring-shaped surface (29f) of the respective valve ring is biased by operating pressure. The piston / cylinder unit according to claim 24, wherein 28. The piston-cylinder unit according to claim 24, wherein the valve ring has a circumferentially extending groove (29a) in a surface covering the leak. 29. The valve according to claim 29, wherein the groove has a width in relation to the thickness of the valve ring, whereby at least one elastic sealing lip (29b) is created.
A piston / cylinder unit according to claim 28. 30. The valve closing member (29), wherein the valve closing member (29) is a valve ring.
The piston-cylinder unit according to claim 2, characterized in that the piston-cylinder unit is formed by a ring (29) and that the valve ring (29) is alternately driven and pressure-urged from two directions. . 31. The first valve closing member (29) is provided with a valve ring.
The piston-cylinder unit according to claim 2, characterized in that the piston-cylinder unit is formed by a ring (29) and the valve ring (29) is configured in a mirror-image manner. 32. A has an essentially concave surface shape in the direction to come the valve ring (29) flows, whereby the direction urging pressure possible surface of the surface to be sealed to the valve ring (29b) is characterized in that there is (29b).
The piston / cylinder unit according to any one of the above. 33. The supporting surface in the slider (35) (33), having at least one surface region (33a) oriented in the direction of the surface to be closed leakage by the valve ring (29) The piston / cylinder unit according to claim 24, characterized in that: 34. The valve ring (29) having at least one surrounding groove (29a), the groove defining a free space used for thermal expansion compensation. Item 34. The piston-cylinder unit according to any one of Items 24-33.