FR2591983A1 - TELESCOPIC TUBE - Google Patents

Abstract

An inner tube 1, of triangular section, comprises two sliding bushings 5, on which slides an outer tube 2 connected in rotation with the inner tube. A recess 4 is made on the inner tube 1, between the two sliding bushings 5. The outer tube 2 has at 3, towards one of the bushings 5, a triangular section which is angularly offset with respect to its triangular section at 6. located towards the other bushing 5, so as to create an effect of torsion of the inner tube 1, improving guidance and eliminating any play. Application: steering columns for motor vehicles, adjustable in height. (CF DRAWING IN BOPI)

Description

"TELESCOPIC TUBE"

  The present invention relates to a telescopic tube, in particular for vehicle steering columns

  mechanically resistant to the folding and

  height, this telescopic tube being composed of a

  inner tube of triangular section and an outer tube

  ne, which in their overlapping areas are rotationally connected in a torsion-resistant and play-free manner

  through two sliding bushes

  around the inner tube by projection or surmou-

  age, and allowing a relative flow along the axis

longitudinal axis of the telescopic tube.

  Steering columns of this kind are currently

  well known, and they have long been involved in the construction of motor vehicles. In particular, they are mounted on cars of

  modern design, which are currently reaching

  its exceeding 200 km / h. At such speeds, known telescopic tubes pose certain problems which are considered very troublesome. So, at speeds here

  mentioned, are generated vibrations whose frequency

  quences are located at 20 to 30 Hz and which bring the outer tube of the telescopic tube into resonance, so much so that even the smallest clearance between the inner tube

  and the outer tube is sufficient to cause a noise of cli

  quetis. This game can, for example, result from the simple fact that the sliding bushings made of

  synthetic, contract under the influence of

  erature, for example when the temperature drops below

below 20 C.

  The present invention aims to eliminate these drawbacks

  and it proposes to provide a telescopic tube

  copic of the kind indicated above in which, by very simple constructive means, it is obtained a precise guide and without play of the inner tube in the outer tube,

  this under all conditions including temperature.

  For this purpose, in the telescopic tube according to

  one of the faces of the inner tube has a recess situated between the two sliding bushings, and the overlap zone situated in the part comprising one of the sliding bushings has, in cross-sectional view, an angular offset with respect to to the overlap area in the part containing the other

sliding sleeve.

  By this particular relative arrangement of the sections, when the inner tube is introduced into the outer tube, a torsion torque is obtained which leads to a deformation of the inner tube, which is

  permitted by the recess formed in this inner tube.

  In an advantageous embodiment of the invention,

  tion, this torsional deformation of the inner tube

  located in the field of elastic deformation of said tube.

  In other words, a certain limit value should not be exceeded for the angular offset between the sections of the two overlapping areas. this value

  being itself dependent on the design and

constituent of the inner tube.

  The inner tube thus undergoes, in its area of elastic deformation, a kind of twisting which creates stresses, resulting in the existence of a restoring force and the support of the different faces of the tube.

  triangular section against the corresponding faces.

  of the outer tube. In this way, there is a total absence of clearance between the inner tube and the outer tube, which remains even if the sliding bushings retract more or less for example to the

  following a drop in the outside temperature. In addition

  their, the return force generates, between the sliding sleeves of the inner tube on the one hand and the outer tube on the other hand, a friction which, by a suitable choice of the angular offset between the two sections, can be adjusted so to provide optimum resistance when adjusting the height of the steering column,

  in the particular application here considered.

  Another advantage of the telescopic tube structure

  According to the invention, this structure necessarily leads to a compensation of the manufacturing dimensional tolerances between the inner tube and the outer tube. In any case, the invention will be better understood

  using the following description, with reference to the drawing

  schematic annexed representing, by way of non-limiting example, an embodiment of this telescopic tube: Figure 1 is a longitudinal sectional view of a telescopic tube according to the present invention; FIG. 2 is a cross-sectional view of this telescopic tube, along the line II-II of FIG. 1. FIG. 3 is another cross-sectional view of this telescopic tube, along the line III-III of FIG. 1. The telescopic tube, shown in Figure 1, consists essentially of an inner tube 1. of triangular section, and an outer tube 2. Two sliding sleeves 5, made in a known manner of synthetic material. projected or overmolded around the inner tube 1, are provided in the areas of overlap between the inner tube 1 and the outer tube 2. The sleeves 5 form sliding bearings, allowing sliding

  perfect of the inner tube 1 with respect to the outer tube 2.

  According to the invention, the inner tube 1 has, between the two sliding bushes 5, a recess 4 which,

  in the form in question, results from a removal

  material in the wall of one of the three wings

  of this tube 1 of triangular section; this is well

  ble on the sectional view of Figure 3.

  As clearly shown in Figure 2, the tube

  external 2 is also realized, in part, with a

  triangular shape, this in its areas of overlap with the inner tube 1. This figure 2 also indicates

  the manner in which, according to the invention, the triangular sections

  3 and 6 of the outer tube 2 in the two overlapping areas are, according to the invention. angularly offset from each other, for clarity of the drawing, the section 6 located outside the section plane (along the line II-II) is shown simply in phantom in Figure 2. Due to the offset angular of the two sections 3 and 6 of the outer tube 2, the inner tube 1 undergoes torsion while remaining in its elastic deformation area, and this inner tube 1 thus acts substantially as a spring

torsion.

  Of course, the invention is not limited to the sole embodiment of this telescopic tube described

  above, as an example; it embraces

  all variants of implementation and application

  the same principle. In particular, the

  4 of the inner tube 1 is feasible in forms different from that previously described, provided that it leads to a reduction of the resistance torque to the

twist in the relevant part.

Claims (4)

  1. Telescopic tube, in particular for columns   management of mechanically resistant motor vehicles   bending and adjustable in height, consisting of an inner tube (1) of triangular section and an outer tube (2), which in their overlapping areas are rotatably connected torsionally resistant and   without play via two sliding bushes-   (5) applied around the inner tube (1) by projection   or by overmolding, and allowing relative sliding along the longitudinal axis of the telescopic tube, characterized in that one of the faces of the inner tube (1) has a recess (4) located between the two sliding bushes (5). , and that the overlap area in the portion having one of the slip bushes (5) has, in cross-sectional view, an angular offset with respect to the overlap area   located in the part with the other sliding sleeve (5).   Telescopic tube according to claim 1,   characterized in that the outer tube (2) also has   a triangular section, in its areas of overlap   with the inner tube (1), and in that the triangular sections (3 and 6) of the outer tube (2) in the two overlapping areas are angularly offset one compared to each other.   Telescopic tube according to claim 1 or 2,   characterized in that the inner tube (1) is positively   mounted, a torsion in its deformation domain elastic.   4. Telescopic tube according to any one of   Claims 1 to 3. characterized in that the recess   (4) of the inner tube (1) results from a removal of. material in the wall of one of the three wings of this tube (1) of triangular section.