DE3501552A1 - Hydraulic shock and vibration damper - Google Patents

Abstract

The invention relates to a hydraulic shock and vibration damper with a cylinder closed at one end in which a piston with a piston rod can be displaced in a sealed manner, having a transfer opening in the piston into which there projects a control element which is fixed to the cylinder and by means of which the transfer cross-section from the cylinder space below the piston to the piston-rod space above the piston can be altered as a function of the piston stroke, having a separating piston which is freely displaceable in the piston-rod space and above which the piston rod is filled with a compressible medium, and having a non-Newtonian damping fluid in the cylinder space which, when the damper is loaded, can be forced backwards and forwards between the cylinder space and the piston-rod space with the displacement of the separating piston, the control element being a tube which is open towards the piston-rod space and has additional transfer openings, distributed in the longitudinal direction of the tube, in the tube wall.

Description

Hydraulic shock and vibration damper

Description The innovation concerns a hydraulic shock and Vibration damper of the type specified in the generic term of protection claim 1.

In a damper of this type known from DE-PS 29 42 029 the control element is a conical pin which is inserted into the continuously formed in the piston The overflow opening protrudes and in this way, depending on the piston stroke, the one for pressing through of the damping fluid present cross-section changed. The conicity of the pen must be very precise so that a desired damping behavior is achieved. He must also be made of high quality material and have a high surface quality, which makes its production very expensive overall. The well-known damper is also complex and expensive to produce. To limit the extension of the piston rod a cable stop is required for the additional components in the construction of the damper must be incorporated.

The innovation is based on the task of providing a hydraulic shock and to create vibration damper of the type mentioned at least equivalent effect is easier and cheaper to manufacture.

The task set is renewed by the in the characterizing Part of the protection claim 1 specified features solved.

In this design, the damping fluid is indeed through the flow opening of the piston, but it must first open the additional throughflow openings of the Push through the tube. Because the piston makes the additional flow openings dependent on the piston stroke covers, the throttle cross-section for the damping fluid is in the desired manner changes. It can be achieved through the arrangement of the additional throughflow openings Predetermine and vary the damping behavior in a wide range. the Manufacture of the pipe and its fastening is much easier and cheaper, than that of the conical control pin in the known damper. Furthermore, the important one The advantage is that the construction of the damper has a cable stop from the outset is integrated, which prevents the piston rod from being pulled out too far.

The damping fluid consists of commercially available components and is insensitive to temperature and stress.

A useful embodiment of the innovation is based on claim 2 emerged. With this sliding fit, friction conditions are constant from the outset predetermined between the tube and the piston, the contained in the damping fluid Fluid brings about a lubricating effect in this area, which also with long idle times prevents mechanical wear.

A further, expedient embodiment emerges from claim 3. The sliding ring located in the piston, which is ultimately used to cover the additional Overflow openings is responsible, receives a secondary function with which it increases the flow cross-section when pulling out the piston rod, so that the It can be pulled out quickly and with little effort. This also has the advantage that the compressible medium only needs a low pressure to restore the damper postpone.

The embodiment according to claim 4 is also expedient because the The valve function of the sliding ring can be precisely determined in advance and the sliding ring is automatic works so that when the damper is compressed, the damping fluid flows through the additional flow openings of the pipe and during the relief or extension stroke in turn automatically both through the additional through-flow openings as well the then enlarged flow cross-section in the piston forces. Manufacturing technology this variant is simple. The assembly does not cause any problems either.

Another important aspect is contained in claim 5. The sliding bush ensures that the frictional forces between the pipe and the Sliding ring have no influence on the damping behavior of the damper.

The variant of claim 6 is also structurally simple.

The cap nut is a commercially available part that is easy to bear heavy loads can be set on the pipe so that the pressure stop - without the flow to hinder the damping fluid - is relatively highly resilient.

Another advantageous embodiment is based on the claim 7th emerged. These pressure relief ducts have the positive effect that the for the Piston rod in the cylinder required seals only with low pressures be hit because the effective pressure in this area is via the relief channels can degrade into the piston rod space as lower pressures prevail, than in the actual cylinder space. So far these seals have been made with up to 400 bar is applied, while the relief channels the application pressure for this Reduce seals to 5 to 25 bar. This increases the service life of these seals much longer. Manufacturing is simplified if the seals and the guide rings can be fitted in the cylinder in the grooves provided there. The piston rod can have a smooth continuous surface, which is also the The service life of the seals and the guide rings benefits.

In terms of assembly technology and structural complexity, there is also an embodiment favorable, as indicated in claim 8.

The embodiment of claim 9 is also expedient because it means There is no need for expensive welded connections, so that the cylinder is absolutely warp-free is guaranteed. If this union nut is part of the mounting flange of the Damper, no further structural measures are required to attach the damper more necessary.

Another and i for the service life of the damper and the wear and tear favorable AusQuhr ~ nOsSorm emerges from claim lo. The two of them are different designed seal gene are only exposed to one medium, which also it is avoided with high reliability that the compressible medium does not interfere with the DaD, ungslluit or vice versa mixed together.

A further, advantageous embodiment emerges from claim 11. The damping fluid can easily pass through this bore in the separating piston filled or the part of the damper to be filled with damping fluid is slightly vented will.

The embodiment of claim 12 is also expedient because it is also In this area of the damper, difficult to control tail connections can be dispensed with and the assembly of the piston rod becomes easy. The tightness and resilience in this area, however, there is no problem.

Another important aspect emerges from claim 13 The gas filling hole allows easy and problem-free filling of the piston rod space with the compressible medium and also a refilling or partial emptying, because the elastomer flap check valve is easy to operate and automatic causes a temporary closure.

The embodiment of claim is also advantageous with regard to this 14, because it ensures a permanently firm lock for the piston rod space is.

The Durchströmmöiinungen are preferably helical on the pipe distributed.

An exemplary embodiment is explained below with the aid of the drawings. It shows: FIG. 1 a longitudinal section through a hydraulic shock and vibration damper at a load, FIG. 2 shows a detail from a longitudinal section through the damper of FIG. 1, during a relief stroke, and FIG. 3 shows a damping force / displacement diagram of the damper according to FIGS. 1 and 2.

A hydraulic shock and vibration damper 1 according to the figures 1 and 2 is used in particular as an elevator damper, impact damper, vibration damper or Bumper damper used for vehicles. It comes with a mounting flange 2 attached to a cylinder 3. Instead of the mounting flange 2, a central mounting flange 2 'could also be attached to the cylinder 3, so that the lower end of the cylinder 3 in tight spaces on the Attachment area protrudes. If a mounting flange 2 'in the middle of the Cylinder 3 is provided, is expediently a lower end of the cylinder 3 completed by a cap nut 4 indicated by dashed lines, which is an in the end 7 of the cylinder inserted closure piece 5 with a sealing ring 6 defines. If, however, the fastening flange 2 is provided at the lower end of the cylinder, then this expediently at the same time part of the nut securing the locking piece 5.

In the opposite, upper end 8 of the cylinder 3 are on the inside circumferential grooves 9 arranged axially spaced, in which guide rings 10 directly sit. Furthermore, annular grooves 11 and 12 for seals 13, 14 are arranged there, the for sealing a hollow piston rod inserted in the cylinder 3 from the open end 8 15 serve. In the designated 25, upper end of the piston rod 15 is a locking piece 16 used, which has a central gas filling hole 17 through the underside an elastomeric flap check valve 18 is closed. In addition, there is a Screw plug 19 screwed into the gas filling hole 17 and with a seal 20 sealed.

The locking piece 16 is by a snap ring 22 in an inside circumferential annular groove 21 in the piston rod 15 secured in position. Outside on the end 25 of the piston rod 15 is a baffle 23 placed and with the locking piece 16 screwed against the snap ring 22 by screws 24.

The designated 26, lower end of the piston rod 15 is with a Piston 27 connected, which is guided displaceably in the cylinder 3 with outer seals 37 is. The piston 27 has a central throughflow opening 29, which is at the upper Piston side to a circumferential shoulder 28 and on the lower piston side to one circumferential shoulder 31 leads. There are radial relief channels between the shoulders 28 and 31 30 is provided, which extends from the throughflow opening 29 to the inner wall of the cylinder 3 lead, so that between the seals 13 and 14 and the piston 27 building Pressure in the throughflow opening 29 can be reduced. On the shoulder 31 of the piston 27 is followed by an enlarged bore area 32 in which axial flow channels 33 and a snap ring 34 are arranged. In the bore area 32 is a slide ring 35 slidably held, which contains a sliding bush 36. The distance between the snap ring 34 and the shoulder 31 is dimensioned such that the slip ring 35 an axial relative movement within the piston 27 between two axial positions able to carry out. In the one position according to FIG. 1, the sliding ring 35 rests the shoulder 31 and blocks the connection from the flow channel 33 to the flow opening 29 from.

In the other position (Figure 2) it rests on snap ring 34 and establishes a flow connection from the flow channel 33 to the flow opening 29.

In the closure piece 5, a tube 38 is screwed, which with his overhead end 40 protrudes through the piston 27 in such a way that between its outer circumference and the inner wall the throughflow opening 29 is an annular space free.

within the longitudinal extent of the tube 38 are additional throughflow openings 39 provided. The shape, size and arrangement of the additional flow openings 39 is freely selectable and leaves the damping behavior of the damper 1 within a wide range predetermine.

A cap nut 41 is screwed onto the upper end 40 of the tube 38, has the through bores 42, so that from the interior of the tube 38 a flow connection to the top. The cap nut 41 forms a cable stop for in this way the damper, because when the piston rod is pulled out it falls on the shoulder 28 of the Piston 27 is intercepted and prevents further extension of the piston rod.

In the piston rod 15 is a freely displaceable above the piston 27 Separating piston 43 is provided, which is designed as a pot piston and a central one Bore 44 has, through a screw plug 45 with a seal, not shown is locked. The separating piston 43 has a gas seal axially spaced apart 46 and a paste seal 47.

The inner wall delimits the piston 27 and the closure piece 5 of the cylinder 3 has a cylinder space 48 which is filled with a damping fluid 49. The soothing fluid 49 contains, for example, silicone oil of about 100 to 500 mm² / s at 2 # j, preferably 250 mm² / s at 25 ° C with a weight fraction of about 40's. Furthermore, the damping fluid 49 contains solids in a grain size of 80% 3 # µm in a weight proportion of about 60%. In addition to silicone oil, there is also a folyglycol ether or This or an aliphatic or aromatic di- or tricarboxylic acid ester can be used as the fluid phase of the damping paste 49. As a finely divided solid E.g. can be used aluminum oxide, K-yolite, barium sulfate, Magresiumo # cid, Nolybd # nsülfid, Siliciumdio: #id, titanium diomid, Zinc sulfide, kaolin and / or ivagnesium aluminum silicate.

The paste usable for the damper is preferably one per se known homogeneous paste, as described in DE-OS 32 o7 654. The damping fluid not only fills the cylinder space 48, but also the interior space designated by 50 of the separating piston 43.

Between the closure piece 16 and the separating piston 43 limits the Inner wall of the piston rod 15 has a piston rod space 51, which is connected to a compressible Medium is filled under pressure, e.g. with a gas or compressed air, whereby the medium 52 is under a pressure of 3 to 5 bar when the damper 1 is unloaded.

After assembling the individual components and bringing them in the damping fluid 49 is vented after removing the screw plug 45 until there is no longer any air in the paste. Then the screw plug 45 screwed into the bore 44 with its seal. Then the closure piece 16 used and secured in position by the snap ring 22, with even more removed Screw plug 19, the medium 52 is pressed in, the elastomeric flap check valve 18 opens automatically and when the pressurization is terminated automatically the Gas filling hole 17 temporarily closed. Then the screw plug 19 screwed in, whereby a final tight seal is achieved. After that, will the baffle 23 is placed and the locking piece 16 is fixed with the screw 24 against the snap ring 22 and the impact piece 23 on the end 25 of the piston rod 15 pressed on.

When the damper 1 is loaded in the direction of an arrow 53 the piston rod 15 is pushed into the cylinder 3. The damping fluid 49 is from the cylinder space 48 by the increasingly covered by the sliding ring 35 additional through-flow openings 39 forced and into the interior of the separating piston 43 pressed. This shifts upward in FIG. 1 and compresses the medium 52 to an increasing extent. At the same time, the piston 27 moves further downwards and the cap nut 41 dips further into the piston rod space 51.

The sliding ring 35 is pressed against the shoulder 31 during this movement, so that the damping fluid 49 nlctl; directly through the throughflow opening 29 can flow.

The outside of the piston rod 15 and below the seals 13, 14 building up pressure is through the pressure relief channels 13 in the flow passage 29 largely dismantled inside, in which there is less pressure than outside of the tube 38 in the cylinder space 49.

When the loading is terminated, the pressure prevailing in the medium 52 pushes Via the locking piece 16, the piston rod 15 in the direction of an arrow 54 after above. This movement is followed by the piston 27, while the sliding ring 35 from the shoulder 31 lifts off and rests on snap ring 34. Since also the separating piston 43 down is shifted, the damping fluid 49 from the space 50 of the separating piston 43 is over the bores 42 of the cap nut 41 and the interior of the tube 38 and the additional Through-flow openings 39 and at the same time on the outside of the cap nut 41 through the throughflow opening 29 and the flow channels 33 are shifted downwards (see Figure 2), where the sliding ring 35 has a relatively large flow cross-section 3 did. In this way, the relatively low pressure in the medium is sufficient 52 from quickly resetting the damper 1.

The piston tube 15 is only so far in the direction of arrow 54 moved until finally the cap nut 41 rests on the shoulder 28 and acts as a cable stop works.

The same thing happens with a tensile load on the impact piece 23 in the direction of arrow 54, where then the damping fluid 49 not just through the pressure in the medium 52, but also through the tensile force in the cylinder space 48 below of the piston 27 is displaced back. When the piston rod 15 is extended also for the seals 13, 14 no inappropriately high negative pressure, because over the Relief channels 30 a Druckauscileicb success. From the damping force / displacement diagram according to Figure 2 it can be seen that the damping force build-up is relatively soft at the beginning, i.e.

that the characteristic curve rises accordingly. After that, the impact speed approximately linearly over a relatively long insertion path of the piston rod 15 decelerated to 0 before the damping force drops slightly towards the end of the stroke. away the point marked with x in the course of the characteristic is reset of the piston rod 15. The force / displacement curve when resetting is then linear again and at an extremely low level of strength. Due to the course of the characteristic the result is a great deal of annihilated impact energy, which annihilates in a harmonious way will. The damper 1 can expediently in particular as a crane damper or Use in wide areas of industry, where preferably moving components need to be dampened. It is particularly advantageous that the with precisely predeterminable Friction with the pipe 38 zscooperating slide ring 35 fulfills a valve function, with the sudden large flow cross-section during the relief stroke of the damper is made available for the damping fluid, so that the relief stroke of the Damper largely independent of the load stroke and the necessary strong Throttling for the damping fluid is. This not only leads to an extraordinary quickly resetting damper, but also at a relatively low-shear force Backflow of the damping fluid during the relief stroke, so that the damping fluid less stressed and warmed up with rapidly successive load cycles is, as with the known dampers, so the damping fluid in both loading directions is forced through the strongly throttled overflow cross-section.

Claims (17)

Hydraulic shock and vibration absorbers Protection claims 1. Hydraulic Shock and vibration damper with a cylinder closed on one side in which sealed a piston is displaceable with a piston rod, with an overflow opening in the piston, into which a cylinder-mounted control element protrudes, with the piston stroke dependent the overflow cross-section from the cylinder space below the piston to the above of the piston lying piston rod space is changeable, with one in the piston rod space freely movable separating piston, above which the piston rod with a compressible Medium is filled, and with a non-Newtonian damping fluid in the cylinder space, when the damper is loaded and the separating piston is shifted between the cylinder space and the piston rod space can be pressed back and forth, characterized in that the Control element a tube (38) open to the piston rod space (52) with additional, overflow openings (39) distributed in the pipe's longitudinal direction in the pipe wall, which from the piston (27) can be covered depending on the benhub that on the piston rod side Pipe end 40 is provided against the piston 27 can be applied cable stop, and that the dampening fluid 49 is a homogeneous paste. 2. Hydraulic shock and vibration damper according to claim 1, characterized characterized in that the piston (27) surrounds the tube (38) in a sliding fit. 3. Hydraulic shock and vibration damper according to the claims 1 and 2, characterized in that in the overflow opening (29) #es a piston (27) Sliding ring (35) is relatively displaceable between two axially spaced positions is mounted, which includes the tube (38 »and in one position the outside of the Shuts off the pipe (38) lying through-flow opening part. 4. Hydraulic shock and vibration damper according to claim 3, characterized characterized in that the sliding ring (35) in one position on a shoulder (31) of the Piston (27 and in the other position caught on a snap ring (34) in the piston (27) is. 5. Hydraulic shock and vibration damper according to at least one of Claims 1 to 4, characterized in that the sliding ring (35) contains a sliding bush (36). 6. Hydraulic shock and vibration damper according to claim 1, characterized characterized in that the cable stop is pierced and fastened on the tube (38) Cap nut (41) is. 7. Hydraulic shock and vibration damper according to at least one of claims 1 to 6, characterized in that that the piston 27 is provided with pressure relief channels 30, which a connection from the piston rod space to the area facing the open end 8 of the cylinder 3 above the piston seals 37 by the cylinder 3 in grooves 11, 12, 9 directly pushing the piston rod 15 having seals 13, 14 and guide rings 10 surrounding the outside. 8. Hydraulic shock and vibration damper according to at least one of claims 1 to 7, characterized in that the tube 38 is inserted into one of the underside Bottom piece 5 forming the cylinder closure is screwed in. 9. Hydraulic shock and vibration damper according to claim 8, characterized characterized in that the bottom piece 5 is inserted into the cylinder 3 with a sealing ring 6 and is held by a union nut 4, which is preferably part of a fastening flange 2 for damper 1 is. lo. Hydraulic shock and vibration damper according to at least one of claims 1 to 9, characterized in that the separating piston 43 at least a gas seal 46 and a paste seal 47 axially spaced therefrom carries. 11. Hydraulic shock and vibration damper according to at least one of claims 1 to 1O, characterized in that the separating piston 43 has a bore 44 contains which is closed by a screw 45 with a seal. 12. Hydraulic shock and vibration damper according to at least one of claims 1 to 11, characterized in that on the piston 27 facing away At the end 25 of the piston rod 15, a locking piece 16 is inserted and secured by a snap ring 22 is secured in the piston rod 15, and that on the outside of the piston rod end 25 a baffle 23 placed and with the locking piece 16 against the snap ring 22 is screwed. 13. Hydraulic shock and vibration damper according to claim 12, characterized characterized in that the closure piece 16 has a gas filling hole 17 which passes through an elastomeric flap check valve 18 is closed. 14. Hydraulic shock and vibration damper according to the claims 12 and 13, characterized in that the gas filling hole 17 in addition and the The baffle 23 facing is closed by a screw plug 19 with a seal 20 is. 15. Hydraulic shock and vibration damper according to one of the preceding Claims, characterized in that the overflow openings (39) on the pipe (38) are distributed helically. 16. Hydraulic shock and vibration damper according to claim 1, characterized characterized in that the damping fluid is a paste of a silicone oil, Polygl ~ Jkol or a carboxylic acid ester is finely divided solid. 17. Hydraulic shock and vibration damper according to claim 16, characterized in that the solid consists of aluminum oxide, cryolite, barium sulfate, X neslum oxide, molybdenum sulfide, silicon dioxide, titanium dioxide: #id, zinc sulfide, kaolin and / or Magnesium aluminum silicate is made.