Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D1/00—Steering controls, i.e. means for initiating a change of direction of the vehicle
  • B62D1/02—Steering controls, i.e. means for initiating a change of direction of the vehicle vehicle-mounted
  • B62D1/16—Steering columns
  • B62D1/18—Steering columns yieldable or adjustable, e.g. tiltable
  • B62D1/19—Steering columns yieldable or adjustable, e.g. tiltable incorporating energy-absorbing arrangements, e.g. by being yieldable or collapsible
  • B62D1/195—Yieldable supports for the steering column

Definitions

• the invention relates to a steering device for motor vehicles with a steering shaft according to the preamble of claim 1.
• Steering devices for motor vehicles are often designed to be displaceable in two parts, so that in the event of a head-on collision, the steering device does not endanger the driver by the steering device giving way when the body collides with the steering wheel and the impact energy is absorbed.
• the displaceable steering shaft tube which receives the steering wheel-side steering shaft, is usually arranged in a housing, which is clamped relative to the vehicle chassis by screwing in a predetermined position.
• the screw connection is designed so that in the event of an impact, the shaft end on the steering wheel side with the screwed housing bracket in the axial direction, in the locked state, can be moved by a certain distance. The impact energy is absorbed accordingly by the jam.
• a disadvantage of the known crash systems for steering columns is that, on the one hand, the breakaway force could not be defined essentially independently of the energy absorption force over a wide range. The absorption hold could not be specified exactly reproducible.
• the object of the present invention to propose a crash system for a steering column arrangement, as a result of which the disadvantages of the prior art are eliminated.
• the task is to implement a crash system for steering columns, which enables a defined breakaway force and a defined energy absorption with reproducible behavior.
• the arrangement should have a high stability and be easy to assemble and economically producible.
• a particularly inexpensive and space-saving steering column arrangement with a crash system for energy absorption results from the fact that the steering shaft is mounted in a guide box, which in turn is firmly connected to a holding bracket, the holding bracket having flange-like sliding surfaces on the side, which are clamped, for example, by screwing to the vehicle chassis is.
• the clamping is performed such that i event of a crash, can be play, shifted at ⁇ by several centimeters, the steering shaft compliant with the console.
• the energy absorption element is fixedly connected to the chassis on the one hand and, on the other hand, where the energy absorption takes place, connected to the steering shaft via the console.
• the absorption element is preferably designed as a sheet metal part with a pull tab, which for example we se ball-shaped as a tear bar is mounted between the bracket flange and the chassis.
• This embodiment has the great advantage that the arrangement can be fastened to the chassis with only two fastening means, preferably two screws. This greatly simplifies the execution and also allows quick assembly, which has a positive effect on the overall costs.
• the tightening torques of the screws are advantageously in the range from 15 to 35 Nm.
• the flexural strain is made possible in that at ⁇ play between the sliding surfaces, spaced from the clamp fixtures, spacers are provided WEL cause bending tension when clamped.
• Such elevations can be a few tenths of a millimeter to a few millimeters. These can be provided in the shaft axis direction or laterally to the fastening elements.
• the arrangement is designed such that the breakaway force is decoupled from the energy absorption force in the event of a crash when the steering shaft is moved in the event of an impact.
• the jam should therefore be released immediately in the event of a crash, for which purpose a so-called breakaway element is used to essentially deliver the impact energy to an energy absorption element after the jam has broken loose. It is thereby achieved that the energy absorption over the defined displacement path is essentially no longer influenced by undefined clamping forces and the absorption effect is predetermined by the design of the absorption element
• the surface parts pressed against each other by the jamming are slightly inclined with respect to the sliding direction, ie arranged under a certain wedge angle so that already at the original jamming is reduced immediately after a short displacement by moving the two wedge surface parts apart depending on the angle inclination.
• the housing console which which fixes the steering shaft tube is connected to the chassis via a tear strip. The execution of this tear strip essentially determines the degree and the course of the energy absorption behavior. By appropriately dimensioning this pull tab, the energy absorption behavior can be designed to be optimally gentle for the driver.
• a further preferred embodiment consists in the fact that in the area of the compressed sliding surfaces, elevations are arranged on both sides of the surfaces, which mutually support each other over a short distance, whereby the sliding surface is essentially formed in the short contact zones of the elevations and in the event of displacement, that is to say in the event of a breakaway , one elevation slides off the other elevation after a short distance, for example a few millimeters, and thus generates the desired breakaway in the event of a crash.
• the bending tension can be generated simply by appropriate dimensioning of the sliding surface parts, by the tension being generated by elastic deformation during the clamping, if necessary up to the defined stop of the opposite, clamped parts.
• FIG. 1 Another particularly simple, preferred embodiment of a breakaway element is that at least in a partial area of the clamped flat parts, these opposing clamping surfaces are designed so that the clamping force is released after a short displacement.
• Fig. 1 is a side view of the holding arrangement according to the invention for steering columns
• Fig. La is a side view of the holding arrangement for steering columns m installed condition for the deformation test.
• FIG. 2 shows a cross section through the holding arrangement according to FIG. 1
• Fig. 2a shows a detailed view of the clamp in cross section
• FIG. 3a shows a detailed illustration of a bend-clamped clamping surface arrangement in longitudinal section with inclined clamping surfaces
• FIG. 3b is a top view of the clamping arrangement in accordance with FIG. 3a
• Fig. 4 is a crash force measurement diagram showing the behavior according to the prior art
• FIG. 5 shows a crash force measurement diagram which shows the behavior with a breakaway element
• Fig. 6 is a detailed view of a further, bend-clamped clamping surface arrangement in longitudinal section Elevations as spacing elements between the sliding surfaces
• Fig. 7 is a detailed view of a further clamping surface arrangement in longitudinal section with steps in the clamping area
• a steering shaft with the steering shaft axis 1 is connected to a steering wheel 2 and mounted in a guide box 3, which, as shown in FIG. 1, is firmly connected, for example clamped, to a holding bracket 6.
• the guide box 3 can also be arranged to be adjustable in height and / or in the slow direction.
• the console 6 is in turn attached to the chassis 18 of the vehicle.
• the shaft 1 is designed to be displaceable one inside the other in the event of a crash, with the result that the console 6 also has to be mounted in a range of up to 50 mm in relation to the chassis 18 so that it can be moved slowly in the event of a crash.
• the console 6 is preferably U-shaped and at least partially surrounds the guide box 3 to be accommodated.
• the bearing guide part 4 is fixed, for example, by brackets 5 between the console part 6.
• sliding surfaces 8 are arranged on both sides, which receive an elongated slot 20.
• This is designed as a slot and serves to receive the fastening elements 13, 16, 17 as well as bolts or preferably clamping screws 17.
• the console 6 is preferably designed as a sheet metal part, which can be produced particularly inexpensively if it is punched out and is designed as a bent part. In addition to the cost advantage, this also has the advantage that greater bending stiffness is possible than, for example, with welded structures.
• one end of the bracket-side clamping surface 22 is advantageously 20 m from the starting clamping position in the end region of the running slot, and is advantageously inclined under a wedge angle 15 as a wedge shoe 14.
• the other wedge surface 22 on the screw side is designed as a sliding shoe 13 also inclined at the wedge angle 15.
• the slide shoe 13 is preferably designed such that it slides in the track 20 in the event of displacement. Since the clamping surfaces are no longer below 90 ° with respect to the clamping direction, an immediate breakaway of the clamping force is possible even with short displacement distances. Suitable wedge angles are from 2 ° to 15 °, preferably from 3 ° to 8 °.
• the console 6 is, for example, screwed directly to the chassis 18 with screws 17, the slide shoe 13 preferably being arranged on the screw head side with a washer 21.
• the arrangement is shown in cross section, from which the preferred method of attachment is shown on both sides of the shaft axis 1 on the chassis 18.
• the wedge shoe 14 can, for example, be incorporated directly into the console 6 with its wedge surface. However, this can be produced more easily and precisely if it is used as a separate, disc-shaped part is made and attached to the bracket 6.
• an energy absorption element 9 is additionally provided, which is preferably designed as a sheet metal part with a tear strip and holding tab 9.
• the sheet metal part 7 is designed as a retaining bracket 7, which surrounds the U-shaped bracket 6 in the upper region and is fixed in place with the jamming of the bracket 6 on the chassis 18 in the starting position.
• the tear-open tab 9 is advantageously provided in the upper, flat, U-shaped sheet metal part of the tear bar 7.
• the tear-open tab 9, as part of the tear-off bow 7, is bent against the console 6 in such a way that the tab 9 can be fixed relative to the console, for example clamped or with a welded connection 11.
• the tear-open strip with the retaining tab 9 is located between notch tracks and is adjusted by the material thickness of the tear-iron sheet, by the material strength, as well as by the roll width with the corresponding roll radius. It may be desirable to be able to vary the absorption force profile along the way, for example by varying the roll width.
• the slide shoe 13 is designed such that part of it can slide in the running slot 20 when the console 6 is displaced relative to the slide shoe 13.
• the wedge surfaces 22 between the wedge shoe 14 and the slide shoe 13 move apart when they are designed as a breakaway element and the jamming is broken loose, the holding force or the energy absorption being determined by the tear strip.
• the tear bar 7 is advantageously designed on both sides as a sheet metal tongue, which lies between the chassis 18 and the sliding flange surface 8 of the bracket 6 and is also clamped in place with respect to the chassis 18 by the screw connection 17.
• the console 6 thus moves maximally according to the slot length 20 together with the wedge shoe 14, which thus moves away from the stationary sliding shoe 13, the tear bar 7 also remaining stationary and the tear tab 9, which is fixed to a console part 6, being torn open becomes.
• the bore in the tear bar 7 is advantageously provided with a flange 16 such that the slide shoe 13 is brought together with the flange 16, as can also be seen from FIG. 2a.
• FIG. 3b This arrangement is shown in the top view in FIG. 3b, where the slot 20 can be seen.
• elevations 26, 27 are provided between the sliding surfaces 8, 12, these surfaces are kept at a distance and can be pressed together in the clamping area be what causes an elastic bending of the parts. This bending tension increases the stability of the arrangement significantly. As a result, it is possible to build smaller materials and less material.
• the elevations 26, 27 can be provided on one side either on the console side or on the tearbar side or as an intermediate layer. You must se n spaced relative to the clamp 17 so that a resilient bracing is possible.
• the elevations 26, 27 can, for example, have a knob-like design.
• the method of bending bracing can also be used advantageously in arrangements without the breakaway elements 22, 26, 27 mentioned above. However, a combination enables a particularly economical implementation.
• a further improvement in the reproducibility of the breakaway behavior can be achieved by treating the clamping surfaces 22, that is to say the inclined sliding shoe surface 13 and the wedge shoe surface 14, in a defined manner. This can be done, for example, by specifically roughening and / or coating the surfaces and / or also lubricating them.
• FIG. 4 shows the measured behavior of the breakaway force over a distance of 45 mm in a breakaway diagram, the screw connection being carried out with a torque of 25 Nm. From this it can be seen that the breakaway force was over 9000 N and only drops after a longer path of approximately 5 mm, but a relatively high residual clamping force of approximately 6000 N remains undefined until the path of 45 mm has been worked through. Under Densel ⁇ ben measurement conditions is m FIG 5, the erfmdungsgemasse Behavior shown with an arrangement according to Figure 1. The screw connection was also set with 25 Nm torque.
• the breakaway force reaches 6000 N and drops steeply and defines immediately after about 1 mm of travel, in order to subsequently remain at a low level with breakaway elements with inclined surfaces below 2000 N uniformly over the entire 45 mm travel.
• the absorption energy is thus defined, reproducible and predeterminable by the absorption element after the short breakaway process, such as preferably determining a tear-open tab, for example with energy absorption forces of 1200 to 5500 N.
• elevations 26, 27 are arranged between the sliding surfaces 8, 12, around the sliding surfaces m from the starting position a small distance of a few tenths of a to to hold about 3mm.
• the elevations 26, 27 are to be arranged essentially symmetrically on both sides of the sliding surfaces in such a way that where the elevations are clamped together, short sliding surfaces 12 are formed, which slide off one another in the event of displacement, that is to say in the event of a crash, and thus over a short distance mm range cancel the clamping force effect, with which the energy absorption by the absorption element 7, 9, 11 is then taken over in a defined manner.
• Such projections can be formed, for example, like knob-out and double-sided ⁇ m long shaft axis direction of the screw fixing to be disposed 17th
• the slide shoe 13 is implemented, for example, as a simple washer.
• This arrangement of a breakaway element can be dimensioned in a simple manner in such a way that it can be mounted in a braced manner, as shown in FIG. 6
• FIG. 7 shows another extremely advantageous and easy-to-implement embodiment of a breakaway element.
• the anemic lying, clamped surfaces of the slide shoe 13 and the original wedge shoe 14 are not wedge-shaped, but are designed in a step-like manner.
• the step width of the stair-like formation defines the breakaway path.
• This embodiment is particularly simple and inexpensive to implement.
• the above-mentioned different types of breakaway elements can also be used in a combined form. This arrangement can also be advantageously combined with spacer elements 26, 27 for bending bracing.
• the steering column 25 can absorb larger forces F v by means of an inventive, bend-braced holding arrangement, or the transverse deflection f 1, f 2 is less with the corresponding force acting on the steering wheel 2.
• a Lensaulenan angel 25 for the corresponding measurement setup is ⁇ is provided.
• the steering column 25 is attached to the chassis 18 at two points 23, 24.
• deflections f ⁇ , f 2 measured by - 2mm as shown in the diagram in FIG.
• deflection values of less than -2 mm can also be achieved with sheet metal constructions under the same measuring conditions, which corresponds to the hard specifications required today.
• FIG. 9 shows deflection values of less than -1.8 mm, with the same force and the embodiment according to the invention with bending bracing.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Steering Controls (AREA)

Priority Applications (4)

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Publications (1)

Family

ID=4203151

Family Applications (1)

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Cited By (1)

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Citations (5)

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• 1999
  • 1999-05-17 ES ES99917733T patent/ES2224639T3/es not_active Expired - Lifetime
  • 1999-05-17 WO PCT/CH1999/000208 patent/WO1999061297A1/de not_active Ceased
  • 1999-05-17 EP EP99917733A patent/EP1077861B1/de not_active Expired - Lifetime
  • 1999-05-17 DE DE59910588T patent/DE59910588D1/de not_active Expired - Lifetime
  • 1999-05-17 JP JP2000550721A patent/JP4387591B2/ja not_active Expired - Fee Related
  • 1999-05-17 CN CN99806184A patent/CN1106967C/zh not_active Expired - Fee Related
  • 1999-05-17 US US09/700,369 patent/US6530600B1/en not_active Expired - Lifetime

Patent Citations (5)

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