DE1272146B - Self-pumping, hydropneumatic suspension strut that can be used as an additional spring, especially for motor vehicles - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

B 60 g

German class: 63 c - 41

Number: 1272146

File number: P 12 72 146.9-21 (H 55780)

Filing date: April 13, 1965

Open date: 4th July 1968

The invention relates to a self-pumping, hydropneumatic that can be used as an auxiliary spring Suspension strut, in particular for motor vehicles, with a gas preload Working space, a storage space under low gas tension and a rod-shaped one trained working piston, which is in one with the working space via throttle openings and / or Valves connected cylinder immersed.

There are hydropneumatic suspensions of this type known (German Auslegeschrift 1135 779), which are equipped with additional pumping devices. With a relatively high structural effort these struts can only deliver small amounts of oil by using small pump piston surfaces, so that longer driving distances are required for height regulation.

With other suspensions of the same type (e.g. German Auslegeschrift 1157 089), those with large Working pump volume, correspondingly large oil reserves and large gas spaces must be provided, which are difficult or impossible to accommodate for spatial reasons.

In the case of various designs, the additional pumping device is very complicated and enlarged the overall length of the damper. Suspension struts in which the pumping device is constantly in action, also convey oil when the vehicle vibrates when the vehicle has long since reached its normal position Has. This oil has to get back into the reserve space, which leads to additional flow losses and this is associated with undesirable attenuation phenomena. The large ones required here Flow cross-sections to the reserve space have an unfavorable effect on driving behavior, because they are e.g. Leaning of the vehicle in curves allow the gas cushion of the spring chamber to relax Oil is pressed into the reserve space and thus when driving straight ahead the vehicle due to insufficient spring action sinks in on one side. Attempts have been made to prevent this by having these flow cross-sections to the reserve space when reaching the normal position, which, however, entails, that the spring characteristic hardens almost suddenly.

An air suspension strut combined with a hydraulic shock absorber is also known (patent application B 32761 11/63 c), which has a plunger instead of a conventional piston rod. Otherwise, however, this is not a hydropneumatic suspension with an automatic one Height regulation, as both the self-pumping, self-pumping, hydropneumatic suspension struts, in particular for motor vehicles

Applicant:

Hoesch Aktiengesellschaft,

4600 Dortmund, Eberhardstr. 12th

Named as inventor:
Manfred Löhr, 5868 Letmathe;
Dr.-Ing. Hans-Jürgen Hoffmann,
5850 Hohenlimburg

borrowed facilities as well as a gas bias There is no standing storage space to hold the volume of liquid required for height adjustment.

The same applies to a still known (German Auslegeschrift 1190 812) with a hydraulic one Shock absorbers combined air suspension, with the difference that this non-generic suspension not a plunger, but a relatively thick piston rod forming an inner cylinder has, with which a damping piston of conventional design is firmly connected.

It is also known ("Schweizerische Bauzeitung", 83rd year, no. 7, p. 107 of February 18, 1965) the plunger-like design of a piston for a valveless expansion piston machine for low temperatures for controlling a gaseous medium. Finally, suspension struts of the above type are known (German Auslegeschrift 1183 801), in which the reserve room and / or the work area around the actual damper part are arranged, which by a tubular separation of air and oil and outside air space prevent the dissipation of the heat generated during the damping work. Due to the type of arrangement of the rod-shaped used to control the control processes trained working piston goes into the overall length at least twice the stroke. The run over The elastic seals through the control channels can lead to the premature destruction of the Lead sealing. In addition, the working piston must not only outside with the partition, but also cooperate sealingly with the pump piston on the inside. The pumping effect is

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ratio of the pump piston area to the effective working piston area is limited.

The invention is based on the object of a hydropneumatic suspension of the type specified in the introduction Generate to create improvements with relatively few and simple parts in particular with regard to manufacturing costs, pumping action and service life, because of the short overall length can be used in many ways and has a favorable effect on driving behavior.

According to the invention, these advantages are achieved in a self-pumping, hydropneumatic strut of the type specified in the introduction essentially thereby

Furthermore, a particularly simple structure results from the fact that the working piston is direct and without Interposition of other components channels and throttle bores in the working piston controls on its entire length surrounding regulating sleeve. The gap between the working piston and the regulating sleeve can be dimensioned so that there is a sufficient seal between the various holes or channels is guaranteed, which means that any ίο elastic seal with the exception of the one in each hydropneumatic Suspension strut existing rod seal can be dispensed with.

By coordinating the arrangement of the bores and channels, it can be achieved that that the cylinder of the working piston as a 15 area of the respective working piston stroke ent-regulating sleeve is designed that the working piston to speaking volume of liquid from the Vorratsihrer tightly encloses the entire length, whereby the space is promoted into the work area, whereby Working piston in the upregulation area when rebounding ensures rapid inflation, especially with it Liquid from the storage room via a channel, the effective work surface also at the same time or several check valves are pumped into the interior ao.

the regulating sleeve is sucked in and it is sucked in. The damping can be

springs over one or more non-return valves in self-cross sections in the up-regulating area so much reduced the working space presses, while it is normal, that practically all of the vibration energy area is used with its front side in the regulating sleeve on the vehicle for pumping work. Ordered Openings and / or channels for working with is advantageously a path dependency space and in the Abregeibbereich also given openings for damping. In normal and reduced to Releases storage room. area, on the other hand, the vibration energy can pass through

In a further embodiment of the inventive concept control of corresponding throttle cross-sections in kens, the annular gap between the heat are advantageously implemented. This creates a Schwin working piston and the regulating sleeve in per se known 30 transmission damping achieved.

ter way by one or more piston rings. Another advantage is to be seen in the fact that by

sealed, so that a permanent seal against the increasing pressure difference between is guaranteed. Work and storage room also the energy consumption

Another advantage from a manufacturing point of view is that it is enlarged and thus the damping is load-dependent the channels in the rule sleeve as open grooves on 35 will.

the outer jacket of the regulating sleeve, the strut according to the invention allows fer-

which are sealed against the gas working space and against each other by a drawn-over pipe. According to further features of the invention, the path of the working piston to the outside is through a ball lock limited, which cooperates with an annular groove on the working piston. Furthermore, between the Working space and the interior of the regulating sleeve a constantly open passage and / or a pressure relief valve available.

In a modification of the inventive concept, the working space can also be arranged at the outer end of the working piston, the one with the working space has connected longitudinal bore that is in

ner to forego damping altogether. A vibration damper of conventional design can then be used be arranged parallel to it.

Finally, it is also advantageous that the working piston has no raised heels and can be sanded in a continuous process as well as on his inner end arranged working space only requires an external machining, which is a special inexpensive manufacturing allowed.

Struts according to the invention are both with and without separation of gas and liquid in the Working and storage room functional, with versions can be formed with separation

Normal area over an opening and a ring 50 that the liquid with the outer tube in a channel in the working piston and a channel in the connection and enables good heat dissipation

Gel sleeve is compared with the interior of the regulating sleeve.

commitment. In the drawings are schematic execution

Advantageously, the working space can also be shown within approximately examples of the invention. In the individual

and shows as 55 nen over the entire length of a protective tube

Annular space formed and the path of the working col- F i g. 1 a suspension strut with a solid, rod-shaped

bens to be limited to the outside by a shoulder on the upper cover and on the protective tube.

Finally, the proposed strut is characterized in that the damping load and / or is path-dependent.

In the strut according to the invention is through

the design and arrangement of a rod-shaped replacing a piston of conventional design

Working piston an extremely short length of the Fe-shaped arrangement of the working space within derbeines allows, so that versatile application and over the entire length of a protective tube.

There are options and installation difficulties

can be largely avoided. lower suspension 1 on an axle of a vehicle

trained working piston and arrangement of working and storage space one above the other in one Outer jacket,

F i g. 2 a mechanical lock for the working piston,

3 shows a strut with a hollow working piston and working space at the outer end of the same and Fig. 4 shows a strut according to Fig. 3 with ring

ges and is attached to the structure with an upper suspension 2, is surrounded by an outer jacket 3, sealed at the bottom by a base 4 and at the top by a cover 5 with a rod seal 6. A rod-shaped working piston 7 slides in a regulating sleeve 8 The interior 9 of the regulating sleeve 8 below the working piston 7 is separated from a working chamber 11 by a valve plate 10 and connected to the latter by a check valve 12. The working chamber 11 is divided by a diaphragm 13 into a gas-α working chamber 11 and a liquid working chamber 11 b. A storage space 16 is also divided by a membrane 17 into a gas storage space 16 α and a liquid storage space 16 b and is connected to the interior 9 of the regulating sleeve via a channel 20 and a check valve 21. Into the channel 20 an opening 22 of the control sleeve to the liquid reservoir space 16 makes b in ausgefahrenem working piston the connection of the inner space 9 opens. Another opening 23 connects the interior 9 of the regulating sleeve via a channel 24 with the liquid working space lift. Working space 11 and storage space 16 are separated from one another by a partition 25. One or more piston rings 26 can be provided between the working piston 7 and the regulating sleeve 8.

In order to limit the upward travel of the working piston 7, a lock (FIG. 2) is provided. Two or more bores 27 receive balls 28, which are preloaded by springs 29 against the Working piston are pressed. When the working piston extends, the balls sit in an annular groove 30 and thus prevent its further upward movement. The annular groove 30 is expediently designed so that the inclination of its lower annular surface 31 is parallel to the axis of the bores 27 and thus no component occurs which presses the ball back against the spring force. The working piston moves on again, the ball is pushed back into the bore 27 by the incline of the upper annular surface 32.

In the up-regulating area, the openings 22 and 23 are covered by the working piston 7. During relative movements between the axle and body of the vehicle of the working piston 7, which then operates as a pump piston, liquid is supplied from the fluid supply chamber 16 b through the channel 20 and promoted the check valve 21 into the interior 9 of the control sleeve during the upward movement. During the downward movement of the working piston 7, the check valve 21 closes, and the amount of liquid delivered is pressed through the check valve 12 into the liquid working space 11 &. In this pumping operation, the gas storage chamber 16 relaxes a, and the gas-α working chamber 11 is compressed. The resulting increase in pressure in the interior 9 of the regulating sleeve brings the working piston into the normal position in which the opening 23 is released.

In cases in which the pump performance should not be fully effective, it is also possible to provide an additional continuously open passage 36 in the valve plate 10 by the damping work is performed, by which the pumping work is reduced.

When the vehicle vibrates in the normal range, the interior space 9 of the regulating sleeve is connected to the fluid working chamber 11 and via the opening 23 and the channel 24. As a result, the pressure of the gas working space 11 α constantly acts on the surface of the working piston. The spring force runs in this area in accordance with the pressure curve in the gas working space 11 a. The damping force is determined by the opening 23 acting as a throttle and can become greater the greater the pressure in the working chamber 11. In this way, the damping is load-dependent. When moving the working piston inwards, a corresponding effect can be achieved in that the flow opening of the check valve 12 is dimensioned accordingly and an additional, not shown, spring-loaded force limiting valve is provided between the interior 9 of the regulating sleeve and the liquid working space lift in the valve plate 10.

If the working piston 7 extends so far that the opening 22 is released, then liquid ao from the liquid working space 11 b via channel 24, opening 23, interior 9 of the regulating sleeve, opening 22 and channel 20 in the liquid storage space 16 b. Depending on the load on the working piston 7, the latter retracts again until the opening 22 is covered.

A particularly simple production results from the fact that the channels 20 and 24 are designed as grooves on the outer jacket of the regulating sleeve and are separated from the gas working space 11 α by a tube 33 which, apart from these two channels, is firmly and tightly attached to the regulating sleeve 8 sits, wherein the channels can be offset by 180 ° in the rule sleeve. The tube 33 can simultaneously serve as a spacer between the valve plate 10 and the partition 25 and absorb tension forces.

Another embodiment is shown in FIG. 3, the working space 11 'being arranged at the outer end of the pierced working piston 7'. The storage space 16 'is connected to the interior 9' of the regulating sleeve via the check valve 2Γ. Another check valve 12 'is arranged at the inner end of the pierced working piston T and establishes the connection between the interior 9' of the regulating sleeve and the working chamber 11 '. An annular channel 34 'with openings 23' which connect it to the longitudinal bore 35 'of the working piston 7' can be sealed at the top and / or bottom with piston rings 26 '. The regulating sleeve 8 'also has a channel 24' via which the direct connection between the working space 11 'and the interior 9' of the regulating sleeve via the longitudinal bore 35 ', the opening 23' and the annular channel 34 'in the normal and regulated position will be produced. The opening 22 'leads directly into the storage space 16'. Otherwise, the function in the different working areas of the working piston is the same as in the embodiment according to FIG. 1. Here, too, a continuously open additional passage 36 'can be provided. An exit of the working piston from the regulating sleeve can be prevented by providing an extension 37 'on the upper cover 5' and an extension 39 'on the protective tube 38'. The working piston can then only extend until the projections 39 'and 37' lie on top of one another. By interposing an elastic buffer (not shown here) between these two approaches, dynamic stop forces can also be absorbed.

In the embodiment according to FIG. 4 can be used to achieve a shorter overall length of the work area 11 "within and over the entire length of a strut surrounding and with the working piston connected protective tube 38 'are formed as an annular space. From the longitudinal hole 35 ' of the working piston 7 'lead a channel 40 "through a protective tube cover 41" to the working space 11 ". If there is no separation of gas and liquid in the working space 11 ″ must be from the channel 40 ″ Immerse the tube not shown here in the liquid level.

By appropriate dimensioning of the flow cross-sections the openings 23 or 23 'and the valves 21 or 21' and 12 or 12 'can be on a Damping can be completely dispensed with, so that only the spring forces are effective in the normal range Up-regulating range only pure pumping work is done. This makes it possible to use the shock absorber as an additional spring with level control instead of conventional steel or rubber additional springs to be used in vehicles.

In all of the exemplary embodiments listed, it is possible to rely on a separation between gas and liquid to do without in the work room and / or storage room.

It is also possible to use the working and storage rooms in the illustrated embodiments to be interchanged, whereby the channels and valves must be changed accordingly.

For safety reasons, a space not shown here can be placed between the work space 11 and the storage space 16 Pressure relief valve are provided.

Claims (9)

Claims: 35 1. Self-pumping, hydropneumatic strut that can be used as an auxiliary spring, especially for motor vehicles, with a working space under gas preload, a storage space under lower gas preload and a rod-shaped working piston which is immersed in a cylinder connected to the work space via throttle openings and / or valves , characterized in that the cylinder of the working piston (7 or T) is designed as a regulating sleeve (8 or 8 ') which tightly encloses the working piston over its entire length, the working piston in the regulating area when rebounding liquid from the storage space (16 or 16 ') one or more check valves (21 or 21') are sucked into the interior (9 or 9 ') of the regulating sleeve via a channel (20) and these are sucked into the working space during de-springing via one or more check valves (12 or 12') (11 or 11 ') presses, while in the normal range it is arranged with its end face in the regulating sleeve Openings (23) and / or channels (24 or 24 ') to the working space and, in the de-energizing area, also openings (22 or 22') to the storage space. 2. Hydropneumatic strut according to claim I _1, characterized in that the annular gap between the working piston (7 or 7 ') and the regulating sleeve (8 or 8') is sealed in a manner known per se by one or more piston rings (26 or 26 ') . 3. A hydropneumatic strut according to claims 1 and 2, characterized in that the channels (20 and 24) in the regulating sleeve (8) are designed as open grooves on the outer jacket of the regulating sleeve, which through a drawn-over tube (33) against the gas working space (11 d) and sealed against each other. 4. Hydropneumatic strut according to claims 1 to 3, characterized in that the path of the working piston (7) to the outside by a ball lock (bore 27 with ball 28 and spring 29) which cooperates with an annular groove (30) on the working piston, limited will. _: 5. Hydropneumatic strut according to claims 1 to 4, characterized in that a continuously open passage (36 or 36 ') and / or a pressure relief valve between the working space (11 or 11 ') and the interior (9 or 9') of the regulating sleeve is present. 6. Hydropneumatic strut according to claims 1, 2 and 5, characterized in that the working space (U ') is arranged at the outer end of the working piston (7') which has a longitudinal bore connected to the working space (35 ') which is in Normal area via an opening (23 ') and an annular channel (34') in the working piston and a channel (24 ') in the regulating sleeve with the interior (9') of the regulating sleeve in connection. 7. Hydropneumatic strut according to Claims 1, 2, 5 and 6, characterized in that that the working space (H ") inside and over the entire length of a protective tube (38 ') designed as an annular space ... 8. Hydropneumatic strut according to claims 1, 2 and 5 to ■ 7, characterized in that that the path of the working piston (7 ') to the outside through a shoulder (37') at the top Lid (5 ') and a shoulder (39') on the protective tube (38 ') is limited. 9. Hydropneumatic strut according to claims 1 to 8, characterized in that the damping is load and / or path dependent. Considered publications: German Auslegeschriften No. 1190 812, 801, 1157 089;
German patent application B32761II / 63c made known on November 29, 1956); "Schweizerische Bauzeitung", Volume 83, No. 7, P. 107, dated February 18, 1965. 1 sheet of drawings 809 568/346 6.68 © Bundesdruckerei Berlin