DE19511867C1 - Drawn-tube energy absorption element for vehicle shock absorbers - Google Patents

Abstract

The energy absorption element is in the form of an outer tube (1) and an inner tube (2) removably fitted co-axially in it. The tubes may slide or roll against each other or may be linked via a common redrawing zone for the entire deformation motion. The inner tube can be redrawn outwards. Its outward-redrawn end zone (6) is connected to the outer tube. The outer tube can be redrawn inwards, with its inwardly redrawn end connected to the inner tube. There may be a round wire element (7,8) or roll body elements in the redrawing zone of either or both tubes.

Description

The invention relates to an inverted tube energy absorber tion element, for example for shock absorption in vehicles can be used.

From the published patent application DE 42 41 103 A1 is an energy ab sorption element in the form of an impact absorber known, the one has everting reversible inverted tube, which is Inverted tube for the purpose of inverting at the assigned end on a suitable neten slip tool supports. It also encompasses Stülprohr a fluid-filled pressure chamber with a throttling Drain.

In the patent DE-PS 11 72 558 is a shock absorber described in which an evertable sleeve made of deformable Me tall between two mutually displaceable, arranged cylindrical parts of different diameters is, with one end area on one and with the other end region on the other cylindrical part is firmly attached.

A me described in the published patent application DE 41 34 545 A1 The chanic energy absorption element contains two inside each other sliding profiles, on which one when moving the profiles material strips that can be deformed due to the acting forces flexible and tear-resistant material is attached, the Attachment with at least one of the two profiles follows and be the essential energy absorption contribution in it is that when moving the profiles this flat Be consolidation successively solves.  

A generic Stülprohr energy absorption element is disclosed in US 52 24 574. At this time the inner and outer tubes meet in the undeform Initial state with the ring bent radially outwards flanges against each other and are fixed to each other there. This with the deformation movement in the outer tube larger diameter with inside turned inside out Pipe tapers in diameter from that with the outer Outer tube connected front end to the opposite Forehead.

In the utility model DE 94 16 640 U1 is a generic ßes Stülprohr energy absorption element for hanging a Bumper disclosed on a vehicle in which on the outside Pipe attached to the vehicle attachable connector which has a collar that wraps around the inner tube closes and against which the inner tube rests supported. The inner tube is encircled with one on the outside the predetermined breaking point provided after a predetermined axial deformation path a tearing of the inner tube be works.

From the published patent application DE 37 11 692 A1 is a bumper geranordnung for vehicles known in which the bumper via a rod-shaped holding member with a plastically ver  malleable tube is connected. The pipe is on one Front side with an outer radial collar on a vehicle carrier element set, and the holding member is by the Pipe inserted and lies with its free face or a radially projecting collar on its periphery ner support shoulder of the tube axially.

From the patent US 35 99 757 it is known in order slip area of two that can be pushed one inside the other To provide a reinforcement ring.

From the published patent application DE 43 16 164 A1 is a slip Pipe arrangement with a sleeve tube of smaller diameter and one with this to form a transition area lumpy inverted tube of larger diameter known in the to achieve a desired force-displacement deformation behavior at least the inverted tube with a smaller diameter in the transition area with diametrically opposed longitudinal slots is provided, whose the inverted tube with a larger diameter facing end portions are formed as bores.

In the design specification DE-AS 13 03 268 overload upset parts described, the harmonica-like folded pipe sections have, which are provided with a plurality of longitudinal slots are, with additional ring grooves at the apex of the folds are brought.

The invention is a technical problem of providing of a Stülprohr energy absorption element based on can be produced relatively little effort, comparatively is flexurally and kink-resistant and in which the axial slip pipe movement is well guided.

This problem is caused by a Stülprohr energy absorption element with the features of claim 1 solved. That Ener Gi absorption element is made up of two in a simple manner  sweeping, covering the entire deformation movement away from each other immediately to achieve the desired axia len stub tube movement pipes constructed, of which we at least one is designed as an inverted tube. It is from outer socket tube coaxially received inner socket tube outside and / or the outer everting tube inside, where at the everted end area with the other tube connected is. Because of the mutual overlap of the two Pipes is the energy absorption element very bend and kink stiff, and the pipes support each other, which provides good guidance for their axial deformation movement is provided relative to each other. With the right shape tion of the two tubes can be a desired characteristic of Deformation path of the energy absorption element depending reach the force of action.

In a development of the invention according to claim 2 under supports the attachment of one or more round wire elements or rolling element elements in the or the inverted areas Inverting process, thereby supporting the bending moment is improved.

By an embodiment of the invention according to claim 3 an individually desired inversion behavior of the Pipes by using a slotted, folded, perforated or notched tube profile in the inside out the pipe area is provided.  

Through a development of the invention according to claim 4 additional shock absorber effect by means of the damping Fluidsy stems achieved.

By variable design of the pipe diameter along the inverting tube area can in a further training of the Erfin practically any desired Force / displacement characteristic for the energy absorption element be put.

Preferred embodiments of the invention are in the drawings shown and are described below. Here zei gene:

Fig. 1 shows a longitudinal section through a reversing pipe-Energieabsorp tion element in an extended position,

Fig. 2 is a longitudinal sectional view of the energy absorption element of Fig. 1 in a collapsed position and

Fig. 3 shows a schematic longitudinal section through a further example of a Stülprohr energy absorption element.

The Energieabsorptionsele ment shown in Figs. 1 and 2 is constructed of an outer reverser pipe (1) and an inner reverser pipe (2), wherein the inner reversing pipe (2) engages with a smaller diameter in the outer reverser pipe (1) of larger diameter. Both inverted tubes ( 1 , 2 ) are arranged coaxially to one another with a common longitudinal axis ( 9 ) and consist of a bendable, unbreakable material which enables the inverted tubes ( 1 , 2 ) to be turned inside out. In this case, the inner reverser pipe (2) is turned inside of the captured in the outer reverser pipe (1) end portion (6) on the outside, whereas the outer reversing pipe (1) turned inside from its inner reverser pipe (2) facing end portion (5) on inside is. The outwardly around end region ( 6 ) of the inner everting tube ( 2 ) is fixed via ei ne welded joint ( 13 ) or another suitable connection to a facing inner peripheral region of the outer everting tube ( 1 ). Analogously, the inwardly turned end region ( 5 ) of the outer sleeve ( 1 ) is fixed by a weld connection ( 14 ) to a facing outer circumferential area of the inner sleeve ( 2 ). This mutual arrangement of the two inverted tubes ( 1 , 2 ) to one another results in a high degree of bending and buckling rigidity of the energy absorption element and good guidance of the inverted tubes ( 1 , 2 ) in their energy-absorbing axial relative movement. Accordingly, the inverting takes place by a rolling bending movement through 180 °, forming respective inverting bead regions ( 3 , 4 ), which each form an end face of the inverting tube ( 1 , 2 ). In the two order bulge areas ( 3 , 4 ) a round wire element ( 7 , 8 ), in the case of circular cylindrical sleeve tubes ( 1 , 2 ) a respective round wire ring ( 7 , 8 ), inserted, whereby the support from the bending moment and thus the inverted movement is improved overall. Instead of the round wire elements ( 7 , 8 ) NEN alternatively rolling element, z. B. in the form of Wälzku gels are introduced.

The energy absorption element is shown in Fig. 1 in a largely extended position, in which the Umstülpwulst area ( 3 ) of the outer sleeve ( 1 ) by a distance (d) from an end stop plate ( 15 ) of the inner sleeve ( 2 ) the other end of which forms, is removed. Densel ben distance (d) take in this energy absorption element set ting the end of the inverted bead area ( 4 ) of the inner inverted tube ( 2 ) from a stop bottom ( 16 ) of the outer inverted tube ( 1 ), which accordingly forms its other front end, and the everted inverted tube ends ( 5 , 6 ) from the respective opposite inverted bead area ( 4 , 3 ). If the energy absorption element from the outside, ie via the stop bottom ( 16 ) of the outer spout tube ( 1 ) on the one hand and the stop plate ( 15 ) of the inner spout tube ( 2 ) on the other hand, is subjected to a compressive force, it is deformed by successively turning over Inverted tubes ( 1 , 2 ) on the inverted bead regions defined by the round wire rings ( 7 , 8 ), energy being absorbed by the inverted operation. With this inverted deformation, the two inverted tubes ( 1 , 2 ) are successively pushed into one another until the pressure is released or the energy absorption element finally assumes the position shown in FIG. 2, in which the inner inverted tube ( 2 ) is completely in the outer inverted tube ( 1 ) is recorded. Compared to the extended position of FIG. 1, the energy absorption element has been shortened by a total of a deformation length ( 2 d) which is twice as large as the previous distance (d) of the everting beads ( 3 , 4 ) from their opposite stop surfaces ( 15 , 16 ).

In the position of Fig. 2, therefore, the two order Stülpwülste ( 3 , 4 ) against the stop plate ( 15 ) or the bottom plate ( 16 ). At the same time, the ends of the inverted tube sections ( 5 , 6 ) extend to the respective round wire ring ( 7 , 8 ) of the opposite inverted bead ( 3 , 4 ) within a tube section between the inside ( 2 ) and the outer inverting tube ( 1 ) formed annular space ( 11 ). Since the volume of this annular space ( 11 ) changes due to the successive inclusion of the inverted tube regions, there are overflow openings ( 10 ) in the outer surface of the inner sleeve ( 2 ) between this space ( 11 ) and an interior space delimited by the shell of the inner sleeve ( 2 ) ( 12 ) are provided, of which only two are indicated in FIG. 1 for the sake of simplicity. The interior ( 12 ) is also limited by the stop floor ( 16 ) and the adjoining tubular casing area of the outer sleeve ( 1 ) and by the stop plate ( 15 ) of the inner sleeve ( 2 ). Since the volume of this interior ( 12 ) changes considerably when the two everting tubes ( 1 , 2 ) are pushed together, suitable overflow openings (not shown) in one or more of the boundary walls of the interior space ( 12 ) to the exterior or to a subsequent one are not ge showed fluid pressure chamber provided. When such a fluid pressure chamber is arranged, the interior ( 12 ) and the ring chamber ( 11 ) can additionally be filled with a hydraulic fluid or a gas in order to additionally provide a hydraulic or pneumatic damping effect for the energy absorption element.

If the deformation path from the everting movement has been used up and the position shown in FIG. 2 has been reached, further deformation occurs only with a noticeable increase in the force previously required for the everting process, in the form of a folding of the four in the position of FIG. 2 coaxially inside sleeve tube sections. In the state of FIG. 2, the energy absorption element therefore forms a folding block for the so-called catastrophe, e.g. B. in a serious accident, when the energy absorption element is used as a structural element of a motor vehicle. The ge compared to the everting deformation length ( 2 d) small block length (b) of the energy absorption element is advantageous, which is only slightly larger than half the deformation length (d).

As an alternative to the welding shown on both sides of the everted tube end region ( 5 , 6 ) at the associated circumferential region of the other tube, provision can be made to connect only the eggend end region firmly to the other tube and the other end region only for axial guidance to use the other tube, after which only one tube is used as an active sleeve tube for energy consumption. The end region serving only for guiding the other tube end region can alternatively also not be turned inside out, in which case suitable sliding or rolling elements are then inserted between these unfixed tube end region and the opposite peripheral region of the other tube. As a further modification, if necessary, a narrowing of the diameter of one or both areas of the inverting tube ( 1 , 2 ) to be inverted can be provided as the inverting length progresses. While the pipe design shown with a constant diameter leads to a constant forming force along the inversion path, such a modification can be used to achieve an increasing forming force to increase the forming force, which is often desirable. Of course, other force / displacement characteristics can also be achieved by changing the diameter.

Further advantages of the energy absorption element shown be stand in that an easy start without the need for a Triggers is possible that there is no noticeable springback and that the stip / slick effect is eliminated. In addition to the use dung as a structural element of a motor vehicle, for. B. in one Longitudinal beam, the energy absorption element according to the invention also elsewhere in the vehicle, e.g. B. as a deformable steering column or deformable jacket pipe, or outside of vehicle construction can be used wherever such deformation and / or damping elements are required.

Fig. 3 shows a variant of the Stülprohr-energy absorption element of FIGS . 1 and 2, in which in turn an outer Stülprohr ( 21 ) with an inwardly turned end region ( 23 ) and an inner Stülprohr ( 22 ) with an outwardly turned end region ( 24 ) are provided, which are now seamlessly formed from one piece to form an intermediate region ( 25 ) which connects the two everted end regions ( 23 , 24 ) coaxially to the two inverting tubes ( 21 , 22 ). In this Stülprohr- energy absorption element, the two Stülprohr- energy absorption element ( 21 , 22 ) consequently by the everting process itself, by which the length of the connecting intermediate region ( 25 ) changes, with respect to the axial energy absorption movement parallel to the longitudinal axis ( 26 ) of the energy absorption element to stabilize each other. If necessary, sliding or rolling elements, not shown, can be inserted between the intermediate pipe area ( 25 ) on the one hand and the outer ( 21 ) and / or the inner sleeve ( 22 ) for further improved guidance.

A further variant for improved pipe routing consists in tapering the outer inverting tube ( 21 ) by means of a suitable roller tool to an outer diameter shape ( 27 ), as is indicated by dashed lines. This taper takes place shortly behind the bent end of this tube ( 21 ) to the diameter of the tube-connecting intermediate region ( 25 ), so that the outer sleeve tube ( 21 ) in the overlap region with the inter mediate region ( 25 ) abuts against it and in this way by the sem is safely guided axially.

Leave the Stülprohr energy absorption elements described for example in the upper part facing the occupants integrate a steering column of a motor vehicle to get there with regard to lateral forces, e.g. B. by friction and tilting, unemp sensitive, axially leading, rigid, torsional stiff and largely play-free deformation element to provide short block length. With such a deforma tion element can take into account the fact that the Coefficient of friction strongly from tolerances, type of surfaces, temperatures etc. is dependent, the static and sliding friction shares at gerin eng number of friction points and low load on them are desirably kept low.

Claims (6)

1. Stülprohr energy absorption element, with

• - an outer ( 1 ) and an inner tube ( 2 ) which can be accommodated coaxially in the outer tube,

characterized in that

• - The tubes are axially sliding or rolling or connected via a common inverted area over the entire deformation movement directly to each other, wherein
• - The inner tube is formed as an evertable inverted tube, the outwardly inverted end region ( 6 ) of which is connected to the outer tube, and / or the outer tube is designed as an inwardly invertible inverted tube, the inwardly inverted end region ( 5 ) is connected to the inner tube.

2. Stülprohr energy absorption element according to claim 1, further characterized by a round wire element ( 7 , 8 ) or rolling element elements in the inverted area of the outer ( 1 ) and / or the inner tube ( 2 ). 3. Stülprohr energy absorption element according to claim 1 or 2, further characterized in that at least one of the two tubes ( 1 , 2 ) is provided on its inverting length with a slotted, folded, perforated or notched profile. 4. Stülprohr energy absorption element according to one of claims 1 to 3, further an integrated fluid damping system with one or more overflow openings ( 10 ) at least in the wall of one of the pipes ( 1 , 2 ) for fluid connection of an annular space ( 11 ) between the two Tubes and a radially inner space ( 12 ) delimited by the two tubes with one another and / or with an outer space radially outside the tubes. 5. Stülprohr energy absorption element according to one of claims 1 to 4, further characterized in that at least one of the two tubes ( 1 , 2 ) along its inversion length has a variable diameter for a defined influencing the force / displacement characteristic of the energy-absorbing order has everting movement .