DE20012513U1 - Telescopic steering system for a motor vehicle - Google Patents

Description

LOESENBEOfc ««STRA-CKE · SPECHT · DANTZ

PATENT ATTORNEYS
EUROPEAN PATENT AND TRADEMARK ATTORNEYS

Dr. Otto Loesenbeck (1931-1980)
Reiche GmbH & Co. KG Dipi.-ing. A. stracke

Automotive Components Dipl.-Ing. Kgr;.-Ogr;. Loesenbeck

Gasstrasse 7,9,16 ™ ^P !"? ^hys *' ^ ¹

Dipl.-Ing. J. Dantz

32791 Location

Jöllenbecker Strasse 164
D-33613 Bielefeld
Phone: +49(0521)98618-0
Fax: +49(0521)890405
E-mail: [email protected]
20/8 Internet: www.pa-loesenbeck.de

July 17, 2000

Telescopic steering system for a motor vehicle

The present invention relates to a telescopic steering system for a motor vehicle according to the preamble of claim 1.
5

Such a steering system is known from DE 32 02 669 Al.

The inner tube has a triangular cross-section, while the outer tube is adapted to this cross-sectional shape and runs at a distance from the inner part. The circumferential gap between the inner part and the outer tube is partially filled with plastic in the longitudinal axis direction, forming a sliding bushing that enables a play-free transmission of a torque applied to the inner part to the outer tube.

However, the given friction coefficient hinders a very smooth height adjustment of a connected steering wheel, i.e. a very smooth axial displacement of the inner part and the outer tube relative to each other, as is desirable.

LOESENBECK · STRACKE · SPECHT · DAwi"Z - PATENT ATTORNEYS - EUROPEANVATENT AND TRADEMARK ATTORNEYS

Registration text dated 17.07.2000 Page 2

The present invention is therefore based on the object of designing a steering system of the generic type in such a way that, while maintaining a play-free torque transmission between the inner part and the outer tube or the outer tube and the inner part, the friction coefficient during the axial displacement of the two parts relative to one another is minimized.

This object is achieved by a steering system having the features of claim 1.

The rolling elements can consist of balls, needles, rollers or coil springs, whereby the elongated rolling elements, i.e. the needles, rollers and coil springs, extend transversely to the longitudinal axis of the inner part and are held in cages just like balls.

The preload can be created, for example, by twisting. The inner part is twisted relative to the outer tube by a certain angle and the restoring forces press the rolling elements against the corresponding inner side of the outer tube, which enables the steering system to rotate without play.

According to a further advantageous embodiment of the invention, the diameter of the coil springs is slightly larger than the width of the gap, so that when the inner part is pushed into the outer tube, the initially circular cross-section of the coil spring is deformed into an oval cross-section. The elastic forces of the coil spring deformed in this way ensure that it is pressed firmly against the inner part on the one hand and the associated inner surface of the outer tube on the other.

Compared to the state of the art, the use of rolling elements has resulted in a significant improvement in the smooth running of the axial displacement between

LOESENBECK · STRACKE · SPECHT · DAWIZ - LAWYERS - EURlSPEAtfPATENT AND TRADEMARK ATTORNEYS

Registration text dated 17.07.2000 Page 3

the inner part and the outer tube. At the same time, during a rotary movement, the torque applied to the corresponding part, i.e. the inner part or the outer tube, is transferred to the corresponding part without play.

When determining the preload, it is essential that the rolling resistance of the rolling elements is so low that the displacement force with which the inner part can be displaced relative to the outer tube is < 85 N, so that the maximum preload torque is below that resulting from the defined torque that must be transmitted without play.
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According to an advantageous development of the invention, the coil springs are designed as tension springs, the windings of which are in a block position before assembly.

Furthermore, it can be provided that the inner part and the outer tube are designed to be polygonal in cross-section, preferably isosceles, wherein, viewed in cross-section, a rolling element is assigned to each leg forming a contact surface.

The rolling elements can be arranged in a common, connected cage, which is pushed onto the inner part before assembly.

The cage with the enclosed rolling elements is expediently guided on the inner part or in the outer tube in such a way that it moves axially relative to both the inner part and the outer tube during longitudinal displacement. This minimizes the rolling resistance compared to the structural situation in which the cage is fixed to the inner part or the outer tube.

Further advantageous embodiments of the invention are characterized in the subclaims.

An embodiment is described below with reference to the accompanying drawings.

LOESENBECK · STRACKE · SPECHT · OAiSl - LAWYERS - EUR©PEAtf PATENT AND TRADEMARK ATTORNEYS

Registration text dated 17.07.2000 Page 4

Show it:

Figure 1 shows a part of a steering system according to the invention in a

Longitudinal section

Figure 2 shows a cross section through the steering system along the line II&mdash;II in

Figure 1.

Figure 1 shows an inner part 1 and an outer tube 2 enclosing the inner part on the outside as part of a telescopic steering system for a motor vehicle.

As can be seen from Figure 2, both the inner part 1 and the outer tube 2 are approximately triangular in cross-section, with legs at the same angle to one another forming support surfaces for rolling elements 3, which are supported on the one hand on the corresponding inner side of the outer tube 2 and the associated outer surface of the inner part 1.

The rolling elements 3 are preloaded and inserted into a gap 5 which is formed uniformly circumferentially between the inner part 1 and the outer tube 2.

The longitudinal axes of the rolling elements 3 run transversely to the longitudinal axis of the inner part 1 or the outer tube 2 arranged concentrically thereto.

The rolling elements 3, which in the present embodiment are designed in the form of rollers, are held in a cage 4 which encloses the inner part 1, which can also be designed as a tube.

However, other designs of the cage 4, which preferably consists of plastic, are also conceivable.
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LOESENBECK · STRACKE ■ SPECHT · DAblf Z - LAWYERS - EUR(S*EAN*ft\TENT AND TRADEMARK ATTORNEYS

Registration text dated 17.07.2000 Page 5

It is also conceivable to provide recesses in the inner part 1 which serve to accommodate the rolling elements 3 in which they roll when the inner part 1 is axially displaced.

Claims (9)

1. Telescopic steering system for a motor vehicle, with an inner part ( 1 ) which is guided in an outer tube ( 2 ) in a torsion-proof manner and so as to be longitudinally displaceable with a displacement force of < 85 N, a gap ( 5 ) being formed between the inner part ( 1 ) and the outer tube ( 2 ), characterized in that rolling elements ( 3 ) which can roll in the longitudinal axis direction of the inner part ( 1 ) and are introduced under prestress are provided in the gap ( 5 ), which rolling elements are supported on the one hand on the inner part ( 1 ) and on the other hand on the associated inner surface of the outer tube ( 2 ). 2. Steering system according to claim 1, characterized in that the rolling elements ( 3 ) are designed as rollers, needles or coil springs extending transversely to the longitudinal axis direction of the inner part ( 1 ). 3. Steering system according to claim 2, characterized in that the rolling elements ( 3 ) are preloaded in the direction of rotation. 4. Steering system according to claim 3, characterized in that the inner part ( 1 ) is twisted relative to the outer tube ( 2 ). 5. Steering system according to claim 2, characterized in that the coil springs are deformed from a circular to an oval cross-section. 6. Steering system according to claim 1, characterized in that the inner part ( 1 ) has a polygonal cross-section and the gap ( 5 ) runs uniformly all around. 7. Steering system according to claim 6, characterized in that the inner part ( 1 ) and the outer tube ( 2 ) have an approximately triangular, isosceles cross-section, the legs forming the support surfaces for the rolling elements ( 3 ). 8. Steering system according to claim 1, characterized in that the rolling elements ( 3 ) are held in a cage ( 4 ). 9. Steering system according to claim 8, characterized in that the cage ( 4 ) with the enclosed rolling elements ( 3 ) is longitudinally displaceable relative to the inner part ( 1 ) and the outer tube ( 2 ).