DE3114882A1 - Fluid-type spring arrangement - Google Patents

Description

"Fluid spring assembly"

The invention relates to a fluid spring arrangement and in particular to such a fluid spring arrangement which makes it possible limit the deflection of the wheels of certain vehicles, e.g. construction site vehicles.

At the moment, only mechanical coil springs or Guinmian stops are known, which have considerable disadvantages; on the one hand, these springs transfer some of the energy that they have stored back, resulting in only one results in moderate damping and, on the other hand, these types of springs are not very reliable over a long period of time. Mechanical Springs namely tire, and rubber stops age, what leads to much less energy absorption than in new condition.

The object of the invention is to avoid these disadvantages and to create a fluid spring arrangement which makes it possible to absorb the kinetic energy of an external moving mass in a relatively small way by the corresponding energy is stored and only to a small extent transferred back to the movable mass will.

The invention accordingly relates to a fluid spring which is characterized in that it is one with a compressible one Having fluid-filled pressure chamber, a piston arrangement which is loaded along at least part of the chamber

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is movable, a device for transmitting an external Force on the piston and a device to compensate for any loss of fluid in the chamber.

The piston preferably has a check valve together with a calibrated throttle opening.

The device for compensating for any fluid losses in the chamber comprises a fluid from atom, means for transferring a pressure to the fluid in the supply reservoir and a control valve connecting the reservoir to the chamber; this valve is preferably a flap valve formed, which is provided with two rods on its two ends, a spring and a valve seat.

The chamber preferably has a stop for setting the rest position of the piston; this stop is moreover designed in such a way that it limits the deflection of one of the flap valve rods.

Preferred embodiments of the subject matter of Invention are explained in more detail below with reference to the accompanying drawings.

Fig. 1 shows a section through the fluid spring arrangement in the middle working position,

Fig. 2 shows a partial section through the spring arrangement in the rest position,

Fig. 3 shows an embodiment of the main reservoir,

Fig. 4 shows a cross section through this reservoir,

and
Fig. 5 shows a partial representation of an embodiment

a fluid spring arrangement according to the invention,

which in certain cases is more advantageous than that

first is.

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According to Figures 1 to 4, the fluid spring assembly comprises a main housing 1, which has a parallelepipedal outer shape has, and in which a bore 2 is introduced, which delimits a pressure chamber 3. A piston assembly 4 formed by a piston 5 and a piston rod 6 is by means of the piston 5 slidably received in the bore 2 of the housing 1. The piston rod of the piston 4 is in the housing 1 by means a bearing 7, which is arranged between these two components and on a shoulder 8 of the bore 2 is present. The bearing 7 is held in place by means of an external threaded ring 9 which is inserted into the bore of the Housing 1 introduced thread is screwed. In this ring 9 a bore 1o is made, which is from the piston rod 6 of the piston assembly 4 on the same diameter is penetrated, which is also provided in the camp 7. Sealing takes place by means of two seals 11 and 12, which are shown in an outer groove 13 rest on the bore of the housing 1 or in an inner bore 14 on the piston rod 6 of the piston assembly 4 are provided adjacent. Similarly, the bore 1o of the ring 9 is provided with a wiper seal ring 15 provided, which prevents the ingress of dust and impurities from the outside.

The piston 5 of the piston assembly 4 is on the one hand with a check valve 16 of known type, consisting of a ball 17, a valve 18 and a passage 19, and on the other hand with a calibrated throttle opening 2o. The openings 19 and 2o open out via a radial passage 21, introduced into the piston rod 6 of the piston assembly 4, in a volume 22 and in this way represent the Communication of the chamber 3 with this volume 22.

On the outside of the housing 1, an extension 23 is provided, provided with a bore 24, which on a Part of its circumference is threaded and has a valve

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contains in the form of a tiltable flap 25, which with two rods 26 and 27, one on each side of the valve body 25, is provided.

The valve body cooperates with a seat 28 through which a channel 29 passes over its entire length and contains a return spring 3o which is clamped between a shoulder in the channel 29 and a collar and itself which is attached to the end of the first rod 26. The valve seat assembly 28 is threaded into the Screwed in section of the bore 24, the seal being ensured by a seal 31, the is arranged adjacent to the bore 2 4.

The second rod 27 of the valve body 27 protrudes into the bore 2 of the housing 1 and is shown in the rest position through Fig. 2, from the piston 5 of the piston assembly 4 into a recess 56 in the surface of the bearing 7, the rests against the shoulder 8, pivoted.

On the wall of the housing 1 opposite the extension 2 3, a reservoir 32 is welded, which is a parallelepiped Has outer shape. This reservoir shown in Fig. 1, 3 and 4 is provided with a cross piece 33, consisting of three ribs 34, 35 and 36; the ribs 34 and 35 are arranged one above the other on both sides of the ribs 36, and they are covered by shells in the form of four side walls 37, 38, 39 and 4o. One of the ends of the reservoir 32 is closed by a bottom 41, while the other end is welded to the wall of the housing 1. the Fluid communication between the pressure chamber 3 and the reservoir 32 results by means of a passage 42 therein Wall. The free flow of the fluid inside the reservoir 32 is ensured by openings 43 in FIG the cross piece 33. The side walls also have a drain screw 44, which is used to remove the air during

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to withhold the filling of the reservoir.

Furthermore, two eyes 57 are provided on the bottom 41, which serve to attach the fluid spring to a chassis or a To attach machine. This reservoir 32 can withstand a very high internal pressure, although it is very light in construction is, because the wall thicknesses of the metal can be kept low because the ribs 34, 35 and 36 are subject to tension and prevent the bottom 41 and the side walls deform significantly.

Finally, a compensation reservoir 45 is attached to the side wall of the housing 1 by means of screws 46, which has the projection 2 3, with a flat seal 47 between the reservoir 45 and the housing 1 Prevents leakage of the liquid.

This reservoir 45 contains a fluid volume 48 and is provided with a first stopper 49 which enables the filling and the level adjustment of the fluid volume 48. Furthermore, a second plug 5o is provided with a hole 51, the leads to the outside atmosphere; the stopper 5o is provided above the stopper 49 in such a way that on the volume 48 atmospheric pressure works.

A fastening eye 52 is attached to the compensation reservoir 48 and, together with the eyes 5 7 to attach the fluid spring to a chassis or machine. These eyes 57 and 52 do not receive the forces the tone of a moving mass 53 (shown in Fig. 1) result, since a buffer 5 4 for intercepting these forces is arranged behind the side that is the piston rod guide side opposite.

In the end of the channel 29 of the valve seat assembly 28, a tube 55 is inserted, which with its other end in

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Direction of the lower part of the compensation reservoir 45 opens in order to prevent air from being sucked in. This Compensation reservoir 45 is made of lightweight material, since it does not have to withstand any high internal pressure, because it is under free air pressure as a result of the bore 51 in the second stopper 5o.

The one used in the various chambers of the fluid spring Fluid is a special silicone-based oil with a relatively high compression coefficient and low viscosity.

Before the spring is put into operation, the chambers 3, 22 and the reservoir 32 are cleared of air bubbles, and the reservoir 45 is brought to the level by means of the plug 49. The operation of the fluid spring according to FIGS 2 is the following:

In the rest state (Fig. 2), the piston rod 6 of the piston assembly 4 is fully extended downward, and their piston 5 rests on the surface of the bearing 7. For this Basically, the piston 5 pivots the second rod 27 of the flap valve 25 into the recess 56 of the bearing 7.

The pivoting of the valve head 25 establishes the communication of the fluid volume 48 of the compensation reservoir 45 with the chamber 22 thanks to the tube 55 in the channel 29 of the valve seat 28; this chamber 22 also communicates with the Pressure chamber 3 via the bore 21, the bore 19 of the check valve 16 and the throttle opening 2o. Chamber 3 communicates with the reservoir 32 via the opening 42.

For this reason, the various fluid volumes 48, 22, 3 and 32 are connected to one another and are also available under atmospheric pressure, since the hole 51 in the plug 5o leads to the free atmosphere.

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The mass 53 to be intercepted comes into contact with the piston rod 6 of the piston assembly 4 and presses the latter upwards with the effect that the rod 27 of the valve body 25 is released and the valve body against his Valve seat 28 is pressed by the return spring 3o.

The main fluid, consisting of volumes 22, 3 and 32 is separated from the volume of compensation fluid 48, see above that now the housing 1 is sealed. Each increase in the internal pressure sets the valve body 25 only more firmly on the Seat 28 and ensures the seal at this level.

The piston assembly 4, which is still to be intercepted Mass 53 is pushed, slides along the bore 2 of the housing 1, the chamber 22 under the piston 5 of the The piston assembly 4 is fed from the volume 3 via the check valve 16 and the throttle bore 2o; accordingly arises no negative pressure below the piston 5 of the piston arrangement 4.

The penetration of the piston 4 into the interior of the bore 2 reduces the total volume of oil contained in the Chamber 3, the reservoir 32 and the chamber 22.

Due to the compressibility of the oil, this reduction in volume causes a corresponding increase in the pressure in the chambers 3 and 32. This pressure leads to an increasing resistance with the way against the action of the external mass 53.

The movement of the piston assembly continues until the reaction of the fluid spring equals the force of action exerted of the mass to be intercepted. When the piston assembly has reached the end of its path, it strikes accordingly the bottom of the housing 1, which in turn by means of the buffer 54 is supported for intercepting the forces.

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The mass 53 to be intercepted has been braked in this way and then stopped. She returns the moment and the piston assembly 4 is released.

The latter returns downwards due to the pressure acting on the cross section of the piston rod 6; The piston 5 is partially balanced due to the presence of openings 19 and 21. Chamber 22 is compressed, and out For this reason, the ball 17 of the check valve 16 sits on its seat 18. The fluid must pass the throttle opening 2o happen. It is accordingly metered out of the chamber 22 into the chamber 3, and the piston assembly 4 can only slowly return and come into stop on contact with the bearing 7 with the result that the rod 2 7 of the valve body 25 in the Recess 56 is pivoted and the communication of the compensation chamber 48 with the chambers 22, 3 and 32 is restored will. The fluid spring is in the rest position again.

During the piston return, most of the Energy stored in the fluid spring in the form of heat is given off in the damping arrangement and accordingly not on carry back the external mass, which is an important advantage of this spring arrangement.

If the heating of the oil caused an increase in internal pressure or a change in temperature caused a contraction caused, or even if minor leakage losses or creep losses of the seals occur, all of these will occur Changes automatically compensated in the rest position from the compensation reservoir.

The embodiment described above according to FIG. 1 to 3 provide good results, especially for vehicles that are not prone to accidents, such as overturning or immerse in liquids such as river water or ponds.

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In this case, namely, the compensation reservoir 45 (Fig. 1), which communicates with the atmosphere, either lose oil from volume 48 or replenish with a parasitic fluid such as water.

To avoid these disadvantages, the! Compensations · reservoir 45 has its own pressure-maintaining means, for example a gas that is enclosed under pressure above the volume of the fluid 48 is.

For this reason, the plugs 49 and 51 must be completely tight.

In addition, it is obvious that the reservoir 45 itself must also be completely tight, in particular in Height of its connection with the wall of the housing 1.

Such seals are relatively easy to achieve with a medium such as oil, but much worse achievable with a fluid, such as gas, that is much less viscous. To prevent the fluid brake from a reservoir with such a sealing quality, the pre-pressure generating devices according to FIG. 5 comprise an envelope 6o, which at least partially has a flexible and expandable wall, but is gas-tight, for example a Cover made of elastomer or rubber.

Advantageously, it is the entirety of the wall of the envelope 6o that is made of such a material.

This envelope 6o is filled with a pressurized gas and installed in the reservoir 45.

This shell 6o can be in the reservoir through an opening 61 are inserted into the wall 62 of the reservoir

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is incorporated and sealed by a plug 6 3, which in turn is either screwed very tightly or even welded in.

The plug 63 could of course alternatively also serve as a refill seal for the fluid volume, if here compressible oil is used.

Once this sleeve has been inserted into the reservoir 45, there is a relative negative pressure around it Shell, and because of the acting on the enclosed gas Under pressure, the entire space 64 above the volume 6 8 is taken up by this shell 6o, the walls 69 and 65 of which to that of the compensation reservoir above the liquid volume level or against the separating miniscus between the volume 48 and the space 64.

Once the envelope 6o has been filled with gas, it is closed by means of a locking member 66 at the opening 67, where the gas was introduced.

These locking devices are known per se and have no manufacturing difficulties, so that they very are reliable and provide the envelope with a good seal over a significant service life.

The pressurization devices described above 4, are very advantageous over those according to FIG. 1. They allow a construction of the compensation reservoir 45 such that it can be easily attached to the housing 1 of the chamber 3 by means of, for example, screws 46 can be screwed on.

The sealing that can be achieved in this way is sufficient to prevent the oil from leaking outwards from the volume 48, in particular at the level of the seal 68 between the walls

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of the compensation reservoir 45 and the housing 1.

Furthermore, the sealing of the gas envelope can be achieved more easily with the materials of which it is made than with those from which such compensation reservoirs are usually made.

Finally, and this is perhaps the greatest benefit, comes from a vehicle that has such a fluid brake has, if the vehicle overturns, no gas in the chamber 3, and there can therefore no malfunctions in the function caused by the fluid spring.

Accordingly, as soon as the vehicle has been set up again, the spring again has the same characteristics and properties on what is not in the form of execution Fig. 1 let reach, because the spring must always work so that the valve and the mouth of the tube 55 are in the lower tier. Namely, if part of the gas from the compensation reservoir 45 into the compression chamber 3, the spring would lose some of its properties and become a "slack" spring, and this would require that the spring would have to be completely refilled in order to give it the desired properties to lend again. In addition, and advantageously, in order to prevent atmospheric pressure from penetrating into the To prevent the compensation reservoir 45, the pressure holding device is kept under pressure in the case of an envelope, which is far above the atmospheric pressure under which the vehicle is moving.

In this case, even if the envelope leaked to the outside, the spring would always retain its quality, as long as the pressure inside the shell would be above that of atmospheric pressure. - This undoubtedly gives the fluid spring according to the invention has a greatly extended service life.

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Claims (16)

Sponsorship claims 1J fluid spring arrangement with a compressible volume of liquid, in which a piston assembly is displaceable, the damping devices acting against the displacement having, and with a supply of compressible fluid to compensate for volume losses, characterized by - A first pressure reservoir (3) in which the piston assembly (4) between two end positions, a compressed and a relaxed end position, is movable - a second reservoir (43) next to the first reservoir such that the first (3) and the second (43) reservoir have a first common wall section (2) with a communication device (42) between the two reservoirs, which communication device (42) is in the area of the compressed end position is provided, and - A third reservoir (48) next to the first reservoir such that the third and the first reservoir one have second common wall section, which is in the relaxation end position of the piston assembly has a controllable fluid valve for fluid communication between the first (3) and third (48) reservoirs. 2. Fluid spring assembly according to claim 1, characterized by means for pressurizing the third Reservoirs (48). 130061/0729 :.:; j: -: - ;: "i 31U882 3. Fluid spring arrangement according to claim 2, characterized in / that the device for pressurizing consists of a pressurized predetermined volume of gas which is sealed is housed in the third reservoir (48). 4. Fluid spring arrangement according to claim 3, characterized in that that the gas volume is enclosed in a shell (6o) which is inserted into the third reservoir (4 8) and at least has a wall section made of a deformable material that is expandable under the gas pressure. 5. fluid spring arrangement according to one of claims 1 to 4, characterized in that the first or the second reservoir (3, 43) has at least one drainage device (44) for Blowing off the atmosphere from the reservoir as it is filled with the fluid. 6. Fluid spring arrangement according to one of the preceding claims, characterized in that the piston arrangement (4) has a check valve (16) associated with the damping device having. 7. Fluid spring arrangement according to claim 6, characterized in that the check valve arrangement (16) from a valve opening (19) is formed, which is the piston (5) of the piston assembly penetrates and on the one hand forms a valve seat (18) and on the other hand a recess for receiving a ball (17), which comes into operative connection with the valve seat (18) when the piston arrangement (4) moves into its relaxation end position. 8. fluid spring arrangement according to claim 6 or 7, characterized in that that the damping device of at least one calibrated throttle opening (2o) is formed, which the The piston (5) of the piston assembly (4) passes through. 9. fluid spring arrangement according to one of the preceding claims, characterized in that the controllable valve in 130081/0729 _ ₃ _ ; ί - - ■; 31U882 The opening position can be brought by the piston of the piston arrangement (4) when the latter is in the relaxation end position. 10. Fluid spring arrangement according to claim 2, characterized in that that the valve is formed by a valve seat body (28) which has a communication opening between the reservoir (48) and a chamber of the first reservoir (3) produces that a flap valve body (25) has a first rod (26), which is immersed in the reservoir (48) which has an elastic restoring element (3o) arranged on the first rod (26) is, by means of which the valve body (25) is biased against the valve seat (28) that on the valve body (25) a second rod (27) is positioned opposite the first rod (26) and into the chamber (2 2) in the path of the piston assembly (4) protrudes in such a way that the piston arrangement actuates the second rod (27) in the relaxation end position lift at least part of the valve body (25) from its valve seat (28). 11. Fluid spring arrangement according to one of claims 2 to 1o, characterized in that the means for pressurizing the fluid contained in the reservoir (48) of a hole (51) is formed, which establishes the communication with the outside air and in the reservoir (48) above the Operating level of the compensation fluid is provided to to expose this fluid to atmospheric pressure. 12. Fluid spring arrangement according to one of the preceding claims, characterized in that the first reservoir (3) a stop (56) for defining the relaxation end position the piston assembly (4). 13. Fluid spring arrangement according to claim 12, characterized in that that the stop is designed such that it limits the movement of the second rod (2 7). 130061/0729 .: .-. ■ - ■■.: ·; ■ "■ ;; '^; 31U882 14. Fluid spring arrangement according to claims 9 to 13, characterized characterized in that the inlet of the controllable valve (25) is connected via a suction pipe (55) that against facing the bottom of the third reservoir. 15. Fluid spring arrangement according to one of the preceding claims, characterized in that the assembly of the first, second and third reservoir is formed substantially parallelepiped. 16. Fluid spring arrangement according to one of claims 3 to 15, characterized in that the gas volume under a predetermined pressure is below a pressure well above atmospheric pressure lying pressure. 130061/0729