DE2010148A1 - Device for absorbing impact forces, in particular for rail vehicles - Google Patents

Description

201 ons

ALFRED TEVES GMBH. February 12, 1970

6 Frankfurt / Main ^! SL / With / Kr

P 3734

H. Erdmann -

Device for absorbing impact forces, in particular for Rail vehicles

The invention relates to a device for absorbing impact forces, in particular for rail vehicles. consisting of a cylinder filled with fluid and a piston which can be displaced via a piston rod in the cylinder against the action of a resilient means and which is guided in a preferably central opening of the piston with a regulating element . '■■ [" ^: ■■■■: _ ■ ;; -_; ■.; ' _: '■ ■; ■■''■' ■ '": ■: ■. ■■ - ■. ^\\:; '..

Devices of this type are used in railroad cars between the The car body and the bumper bars carrying the buffer and couplings are arranged and have the task of preventing shunting impacts occurring acceleration or deceleration to one for f To keep the cargo safe in value.

Thanks to special designs of the regulating organ, it has been possible to the damper force as a function of the damper travel to give favorably regarded course and thus the cargo of the To protect the car to be braked from damage due to excessive acceleration or deceleration. The regulating body is for this basically designed so that the effective passage cross section for the fluid displaced from the cylinder by the moving piston decreases with increasing damper travel. The German

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Patent specification 1 259 370 provides a tubular regulating member, perforated diaphragms are provided in the wall through which the pressure medium passes. The piston sweeps over during the damper stroke these apertured diaphragms, so that the effective passage cross-section is smaller.

In the German patent specification 1,235,979, a throttle rod is described as a regulating element, which is fixed to the cylinder cover is connected and protrudes through the opening of the piston displaceable in the cylinder. This throttle rod has longitudinal grooves, whose cross-sections decrease parabolically with increasing piston stroke, so that the fluid displaced by the piston during the damping stroke is throttled. This means, for example, that a constant damper force over the entire damper stroke or one in the lower range of the The damper force increases and changes to a value that remains constant for the second half of the damper stroke, for example can be obtained.

In all known devices of this type, the regulating member remains also effective in its unchanged form during the return stroke of the piston. It therefore increases as the return stroke increases Passage cross-section for the fluid, as a result of which the car is accelerated further and further until it reaches the central position with considerable Speed is exceeded and is only braked by squeezing the damper again. (Railway Technical Review, ETR 1964, issue 4, page 127 ff).

It is desirable that the relatively strong acceleration at the beginning of the return stroke, which quickly removes the dangerous from the shock absorber Brings out end position, changes into a delay such that the carriage is approximately in the middle position to the shock beam comes to rest.

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The utility model 1 920 866 suggests arranging a non-return valve between the evaporator and the pick-up chamber which, during the return stroke, increases the effective passage area for the fluid. With this it is achieved. That the shock absorber quickly comes out of the endangered end position and can absorb a short-term subsequent shock; but since the check valve during the entire return stroke of the wagon is effectively bleibtF accelerated throughout the μ period and continues with significant speed- "speed the center position, in which he reached only after renewed compression of the damper /

The object of the invention is to overrun the central position of the Substantial mitigation of wagons and a shock absorber device to create that better meets the requirements for the return stroke.

According to the invention this is achieved in that at the passages for the fluid pressure-dependent to be operated yentil- and throttle devices are provided that only during 'the Return stroke or effective in a certain area of the return stroke | are. . .

The parabolic longitudinal grooves of the regulating needle trained regulating organ are closed by flaps that arranged at the implementation point on the annular piston and around their Attachment point are pivotable or rotatable in one direction.

When the system is actuated, these flaps release the pressure medium flow in the direction of the displacement chamber-Aüfnehmerraum and block it in the opposite direction.

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In a blind hole of the regulating needle facing the cylinder cover there is a spring-loaded check valve. In front of and behind the valve body, a transverse bore opens into the blind hole. One of the transverse holes is made by the annular piston during the damping stroke driven over, while the second transverse bore remains in the displacement chamber even with the maximum possible damping stroke. Approximately During the first third of the return stroke, the check valve is pushed through the cross hole in the pick-up area acted upon by the fluid flowing back in the opening direction.

The invention is capable of various embodiments, one being described in more detail below with reference to the drawing.

The figure shows a longitudinal section through a shock absorber according to the invention.

The cylinder 1 filled with fluid is closed with the cover 5. Sealed against the cylinder wall, the annular piston 3 can be displaced via the piston rod 2, which is likewise tightly guided arranged. The regulating needle protrudes into the opening of the annular piston 3 4, the other end of which is anchored in the cylinder cover 5. It points in the direction of the cylinder cover open blind hole 6, in which a check valve is arranged, the valve body Io through a in the cylinder cover supporting helical spring 9 is held in contact with its valve seat 7, which forms a step in the blind hole 6. On both sides of the valve seat 7, cross bores 11, 12 connect the blind hole 6 with the displacement chamber 15 of the cylinder 1. On its circumference the regulating needle 4 has a plurality of longitudinal grooves 13, the cross-sections of which decrease parabolically as the damping stroke increases. At the Implementation of the regulating needle 4 through the annular piston 3 are in recesses of the annular piston 3 around their attachment point

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pivotable or rotatable flaps 14 are arranged which normally close the cross-sectional areas of the longitudinal grooves 13 or leave only one throttle cross-section 16 free. Only with increased Pressure in the displacement chamber 15 give the flaps 14 the full passage cross section of the longitudinal grooves 13 free »The hollow The piston rod 2 formed is divided into two spaces 8, 18 by an overhung separating piston 17. The all-round tightly closed space 18 is filled with pressurized gas, while ^ the space 8 ™ connected to the cylinder interior 15 for taking up the fluid displaced by the annular piston 3 during the damping stroke serves and is also filled with fluid. The annular piston 3 rests in the normal position on a stop machined on the cylinder wall. In this area, the inner diameter of the cylinder 1 narrows down to the outer diameter ν of Piston rod ■ 2, so that a diohtende guide of the piston rod in cylinder 1 is possible. In the transition area between Ring piston 3, cylinder 1 and piston rod 2 an annular space 20, which is larger during the stroke and via bores 19 in the wall of the piston rod 2 connection with the displacement chamber 8 has. In the normal position, the holes 19 are through the Cylinder wall covered »i

The mode of operation of the shock absorber according to the invention is as follows:. "■" - <■ · ■ '""''-. ■■■.: "- '] -'-- .""" ■■■■ -. "- ' - """'" .- ■' ■■ · ^.:

If there is a joint from one of the two longitudinal lines, move it. " piston rod 2 and ring piston 3 against cylinder 1; in the process, the fluid is displaced from the cylinder space 15 and flows through the longitudinal grooves 13 of the regulating needle 4 into the Pick-up space 8 and from here through the cross hole 19 into the enlarging annulus 20. The flaps 16 are thereby from Fluid is applied in the opening direction so that the full flow

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access cross-section is available. That from the displacement room 15 fluid penetrating into the smaller pickup space 8 displaces the separating piston 17 so that the gas in space 18 is compressed and the gas spring is tensioned. While the annular piston moves over the regulating needle 4, the effective one is reduced Passage cross-section of the longitudinal grooves 13, whereby the desired damping comes about. Runs over in the latter section of the hub the annular piston 3 the transverse bore IX in the regulating needle 4, so that this now opens into the pick-up space 8, where, however, the transverse bore 12 even with the maximum possible stroke in the displacement space 15 of the cylinder 1 remains. The check valve IO is acted upon in the closing direction during the damper stroke.

If there is no longer any external force acting from the direction of impact, the pressure conditions in the displacement chamber 15 and the pick-up chamber are reversed 8 um. Since the volume of the pickup space 8 plus the annular space 20 is always smaller than the volume of the displacement space 15, the gas in the space 18 of the piston rod 2 was tensioned by acting on the separating piston 17 during the damping stroke. This gas spring now initiates the return stroke. Due to the increased pressure in the pick-up space 8, the check valve 10 opens, the fluid flows through the transverse bore 11, the blind hole 6 and the transverse bore 12 back into the displacement space. Because the passage cross-section is relatively large, the ring piston is accelerated strongly and quickly comes out of the endangered end position.

If the annular piston 3 has passed the transverse bore 11 on the return stroke, this connection is canceled and the fluid can only still flow back into the displacement chamber 15 through the throttle points 16 on the flaps 14 closing the longitudinal grooves 13.

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The throttling of the fluid causes the annular piston. 3 with the Piston rod 2 delayed so that they approach their normal position only at low speed, thus also when Return stroke a damping occurs. Ring pistons 3 and Piston rod 2 of its Nonnais division shown in the figure, additional end position damping occurs in that the transverse bores 19 connecting the annular space 2O and the pick-up space 8 are gradually covered by the cylinder wall 1, so too the outflow of the fluid from the annular space 20 is throttled. It is thus achieved that the annular piston 3 without metallic Impact softly swings into its normal position «■

The inventive design of the shock absorber is achieved that after a damping stroke carried out in a known manner Return stroke of the piston begins with a quick start and in the second Section of the stroke length changes into a delayed movement. Of the Piston is no longer accelerated over the entire return stroke as in the devices according to the prior art, a new one Compression of the shock absorber as a result of the recoil during a hard metallic impact of the piston in its normal position is avoided. Short-term successive impacts can g Do not damage the shock absorber as it accelerates the end position ™ leaves.

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Claims (1)

ALFRED TEVES GfIBII February 12, 1970 Frankfurt (Main) SL / Mit / llie P 3734 H. Erdraann - 99 Claims / v-1. Device for absorbing impact forces, especially for rail vehicles, consisting of a cylinder filled with fluid and a cylinder with a piston rod in the cylinder against the action of a resilient means of displaceable piston which cooperates with a regulating member in a preferably central opening of the piston is guided, characterized in that that at the points of passage for the fluid pressure-dependent actuated valve and throttle devices are provided, which only are effective during the return stroke or in a certain area of the return stroke. 2. Device according to claim 1, characterized in that that the parabolic longitudinal grooves (13) of the regulating element, which is designed as a regulating needle (4), pass through at the lead-through point on the annular piston (3) around its attachment point in one direction pivotably or rotatably arranged flaps (14) are closed, which have a throttle bore (16), 3 · Device according to claim 1 and 2, characterized in that that the flaps (14) the pressure medium flow in the direction of the displacement chamber-pickup chamber release and lock in the opposite direction. 109839/01 1 6 . ^; : ' ^{:: ί} ; ■ ": ■" .. \ -V ": V ~ -9- - ■■;. ■ ^; ■ -.- ■ ■: _ V-: ρ 3734. 4, device according to one or more of the preceding claims, characterized ge 1 $ e η η ie ic h η et _f that a spring-loaded check valve (lo) is arranged in a blind hole (6) of the gumming needle (4) facing the cylinder cover (3) - and that a cross hole (! Ι) in front of the valve body (Ip) and a second cross hole (12) behind the valve body (10) open into the, blind hole (6) ». 3 »Device in accordance with one or more of the preceding claims, thereby g e Ic e η η ζ e i c h η e t that the one cross hole | ll) is overrun by the Bing piston (3) during the damping stroke, while the second transverse bore (12) even with the maximum possible damping stroke in the Displacer remains in (1-5-), 6. yorrichtnng according to one or more of the preceding claims, characterized geke u η ζ ei ch η e t_ that the check valve (IQ) can be acted upon in the opening direction in the first section of the Bückhubes through the transverse bore (! Ι) located in the pick-up space 109839/0116 / IO Blank page