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 in such a way 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 displaced 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 does not essentially differ from the energy absorption force over a wide range. Chen could be defined independently. The absorption behavior could not be specified exactly reproducibly.
• 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 be easy to install and economical to manufacture.
• 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.
• a so-called breakaway element is used to essentially deliver the impact energy to an energy absorption element after the jam has broken loose.
• the breakaway element For an imple mentation form of the breakaway element are in the area of the clamp fastening, where the large clamping forces occur between the housing console and the stationary chassis part, the flat parts pressed against each other by the clamping against the sliding direction, ie. H. arranged at a certain wedge angle in such a way that the original jamming is immediately reduced even with a short displacement path, in that the two wedge surface parts move apart depending on the angle inclination. In this way, in the event of an impact, the jamming is released after a displacement of a few tenths of a mm and the further displacement is no longer determined by undefined clamping forces.
• the housing console 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.
• 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 sliding metal, i.e. in Breakaway, the elevation slides already after a short zen distance, for example a few millimeters, from the other elevation and thus generates the desired breakaway in the event of a crash.
• 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.
• 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, for example, by screwing on Vehicle chassis is clamped.
• the jamming is carried out in such a way that in the event of a crash, the steering shaft with the console can give way, for example by several centimeters.
• 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 tear-open tab, which, for example, is designed in the form of a ball as a tear ball and is mounted between the console 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 conditions in the range of 15 to 35 Nm.
• This very simple embodiment of the arrangement and in particular the possibility of fastening the entire arrangement with only two fastening screws without a separate console guide also enables use in simple application cases without the aforementioned breakaway elements. In this case, however, the defined separation between breakaway force and energy absorption is less clear, but the arrangement can then be implemented particularly cost-effectively.
• Fig. 1 is a side view of the holding arrangement according to the invention for steering columns
• 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
• 3a shows a detailed view of a 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 is a crash force measurement diagram showing the behavior according to the invention
• FIG. 6 shows a detailed illustration of a further clamping surface arrangement in longitudinal section with elevations as spacer elements between the sliding surfaces
• FIG. 7 shows a detailed illustration of a further clamping surface arrangement in a 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.
• the bracket 6 is screwed onto the chassis 18 in such a way that, in the event of an impact, the steering shaft with the guide box 3 can be moved within the slot length.
• the one bracket-side clamping surface 22 inclined under a wedge angle 15 is designed as a wedge shoe 14.
• the other wedge surface 22 on the screw side is designed as a sliding shoe 13 also inclined under 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 be incorporated directly into console 6, for example, with its wedge surface. However, this can be produced more easily and precisely if it is produced as a separate, disk-shaped part and is fastened to the console 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 a fixed manner from 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 is bent as part of the tear bow 7 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 joint 11.
• the tear-open strip with the retaining tab 9 is located between notch tracks and is adjusted through the material thickness of the rice ball sheet, through the material strength, as well as through the roll width with appropriate 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 aforementioned constructive design of the entire holding arrangement, in which the peel bracket 7 with the sliding surfaces 12 is clamped between the bracket flange 6, 8 and the chassis 18, also has particular advantages without the Use together with the special breakaway elements 13, 14, 22, 26, 27, 29. It enables simple assembly with inexpensive design, good operating behavior and high stability of the arrangement, in particular when the arrangement, as preferred, only with two screws 17 is attached to the chassis 18.
• the slide shoe 13 is designed such that a part of it can slide in the running slot 20 when the bracket 6 is displaced relative to the slide shoe 13.
• the wedge surfaces 22 between the wedge shoe 14 and the sliding shoe 13 move apart here 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 lst. This arrangement is shown in the top view in FIG. 3b, where the slot 20 can be seen.
• 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 a breakaway diagram of the measured behavior of the breakaway force over a distance of 45 mm, 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 the same measurement conditions, FIG. 5 shows the behavior according to the invention with an arrangement according to FIG. 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 defined after the short breakaway process, is reproducible and can be predetermined by the absorption element as preferably determined a tear tab, for example with energy absorption forces of 1200 to 5500 N is specified.
• elevations 26, 27 are arranged between the sliding surfaces 8, 12 in order to move the sliding surfaces m from the starting position a short distance from a few tenths of a mm to approx Hold 3mm.
• the elevations 26, 27 are to be arranged essentially symmetrically on both sides of the sliding surfaces in such a way that short sliding surfaces 12 are formed where the elevations are clamped together, which slide down in the sliding metal, i.e. in the event of a crash, and thus over a short distance in mm. Abolish 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 elevations can, for example, have a knob-like design and can be arranged on both sides in the longitudinal direction of the screw fastening 17.
• the slide shoe 13 is implemented, for example, as a simple washer.
• 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 rather are designed like steps.
• the step width of the stair-like formation defines the breakaway path.
• This implementation is particularly simple and inexpensive to implement.
• the aforementioned different types of breakaway elements can also be used in a combined form.

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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)

Applications Claiming Priority (2)

Publications (1)

Family

ID=4203127

Family Applications (1)

Country Status (7)

Cited By (2)

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Citations (3)

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• 1999
  • 1999-05-20 WO PCT/CH1999/000215 patent/WO1999061299A1/de not_active Ceased
  • 1999-05-20 CN CN99806183A patent/CN1107608C/zh not_active Expired - Fee Related
  • 1999-05-20 DE DE59904962T patent/DE59904962D1/de not_active Expired - Lifetime
  • 1999-05-20 US US09/700,377 patent/US6505856B1/en not_active Expired - Lifetime
  • 1999-05-20 JP JP2000550723A patent/JP4387592B2/ja not_active Expired - Fee Related
  • 1999-05-20 ES ES99919021T patent/ES2192048T3/es not_active Expired - Lifetime
  • 1999-05-20 EP EP99919021A patent/EP1080003B1/de not_active Expired - Lifetime

Patent Citations (3)

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