Suspension strut for a vehicle

Abstract

A suspension strut for a vehicle has an air spring unit and a damper unit. The damper unit has a damper tube, which extends into a rolling tube of the air spring unit. The damper tube has supporting geometries distributed over its circumference, against which supporting geometries a radially expanded end of the rolling tube is supported. In order to support the rolling tube on the supporting geometries of the damper tube, a torsion element is provided. The torsion element is arranged between the radially expanded end of the rolling tube and the supporting geometries of the damper tube. The torsion element forms a form fit with the supporting geometries for the purpose of torque transmission.

Claims

1. A suspension strut for a vehicle, the suspension strut comprising: an air spring unit having a rolling tube with a radially expanded end; a damper unit having a damper tube extending into said rolling tube of said air spring unit, said damper tube having a circumference and distally separated supporting geometries distributed over said circumference, against said supporting geometries said radially expanded end of said rolling tube is supported; and a torsion element for supporting said rolling tube on said supporting geometries of said damper tube, said torsion element disposed between said radially expanded end of said rolling tube and said supporting geometries of said damper tube, said torsion element forming a form fit with said supporting geometries for purposes of torque transmission, said torsion element having interior recesses formed therein and said supporting geometries being disposed in said interior recesses in a formed fitted manner, said torsion element being one of vulcanized on or adhesively bonded to an inner side of said radially expanded end of said rolling tube; and during use of the suspension strut, a relative rotation is produced between said damper unit and said air spring unit about a longitudinal axis of said damper unit, wherein the torque transmission between said air spring unit and said damper unit takes place by an elastic torsion of said torsion element.

2. The suspension strut according to claim 1, wherein said torsion element is configured in several parts and has a shape-stabilizing core body, said shape-stabilizing core body being over molded with a rubber-elastic material via injection-molding.

3. The suspension strut according to claim 1, wherein: said damper tube and said rolling tube defining a pressure chamber formed in a region between said damper tube and said rolling tube; and said torsion element has a sealing lip running around an outside, and seals off said pressure chamber from an inside of said rolling tube.

4. The suspension strut according to claim 1, wherein said damper tube has a wall and said supporting geometries are formed as outwardly curved moldings in said wall of said damper tube using a shaping method.

5. The suspension strut according to claim 1, wherein three said supporting geometries are distributed 120 apart over said circumference of said damper tube.

6. The suspension strut according to claim 1, wherein said supporting geometries have a supporting shoulder facing in a direction of said air spring unit, wherein said supporting geometries fit in said supporting shoulder in said interior recesses in said torsion element.

7. The suspension strut according to claim 1, wherein said torsion element is vulcanized or adhesively bonded on an inside of said radially expanded end of said rolling tube or is pressed into said radially expanded end.

8. The suspension strut according to claim 1, wherein said torsion element is accommodated in a form-fitting manner in said radially expanded end of said rolling tube, said radially expanded end has an inwardly shaped edge, by means of said inwardly shaped edge a form fit is formed between said torsion element and said rolling tube in a direction of a longitudinal axis of said damper unit.

9. The suspension strut according to claim 2, wherein: said torsion element is formed from a rubber-elastic material; said shape-stabilizing core body is formed from a hard plastic material or a metal material; and said rubber-elastic material is a nitrile rubber.

10. The suspension strut according to claim 8, wherein said inwardly shaped edge is an inwardly facing flared flange.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 shows an exemplary embodiment of a suspension strut in a cut away side view, with an arrangement according to the invention of the rolling tube of an air spring unit on the damper tube of a damper unit;

(2) FIG. 2 shows an enlarged view of a detail of the arrangement of supporting geometries on a damper tube, on which a partially shown torsion element is shown;

(3) FIG. 3 shows a perspective view of a torsion element, shown cut away,

(4) FIG. 4 shows a side view of the arrangement of the torsion element on the damper tube, and

(5) FIG. 5 shows a cross-sectional view of the damper tube with a torsion element according to the section line A-A as shown in FIG. 4.

DESCRIPTION OF THE INVENTION

(6) FIG. 1 shows an exemplary embodiment of a suspension strut 1 having the features of the present invention. The suspension strut 1 is used for arrangement in a vehicle running gear and forms a connecting member between a vehicle dome and an axle of the vehicle. The suspension strut 1 has an air spring unit 10 and a damper unit 11. The air spring unit 10 is used to suspend the axle on the vehicle frame, and the damper unit 11 provides damping of the movement of the axle on the vehicle. In order to arrange the suspension strut 1 in the vehicle, connecting bolts 23 are arranged at the end of the air spring unit 10, so that a direct connection is produced between a part of the air spring unit 10 and a spring dome of the vehicle. The damper unit 11 has a damper tube 12, and a fastening eye 24 is arranged at the end of the damper tube 12, with which fastening eye the damper unit 11 can be connected to the axle of the vehicle.

(7) The damper tube 12 of the damper unit 11 extends into a rolling tube 13 of the air spring unit 10, and the damper unit 11 further has a piston rod 25, which extends into the air spring unit 10 and is connected to a part of the air spring unit 10 in a manner not shown in detail.

(8) The rolling tube 13 is supported on supporting geometries 14, which are formed on the damper tube 12 of the damper unit 11. To this end, the rolling tube 13 has a radially expanded end 15, and a torsion element 16 is accommodated on the inside of the radially expanded end 15, by means of which torsion element the rolling tube 13 is supported on the supporting geometries 14.

(9) The damper tube 12 extends along a longitudinal axis 22 of the suspension strut 1, and the exemplary embodiment shows three supporting geometries 14 on the circumference of the damper tube 12, which are situated at the same height in relation to the longitudinal axis 22. The torsion element 16 is arranged on the supporting geometries 14 in such a manner that the supporting geometries 14 fit inside the torsion element 16. A conical fit is produced by the radially expanding end 15 of the rolling tube 13, in which the torsion element fits in a force-transmitting manner. The arrangement of the torsion element 16 on the supporting geometries 14 of the damper tube 12 is shown in more detail in FIG. 2 below.

(10) FIG. 2 shows a view of a partially cut away damper tube 12, on which two supporting geometries 14 have been made by way of example. The supporting geometry 14 shown on the right is visible from the inside of the damper tube 12, and it can be seen that the supporting geometries 14 are formed as mouldings in the wall of the damper tube 12, which curve radially outwards from the inside of the damper tube 12. The supporting geometries 14 have a supporting shoulder 21, against which the torsion element 16 can bear. To this end, the torsion element 16 has recesses 17, in which the supporting geometries 14 can fit. The number of recesses 17 made on the inside of the torsion element 16 corresponds to the number of the supporting geometries 14 on the damper tube 12.

(11) FIG. 3 shows a perspective view of an exemplary embodiment of a torsion element 16, as can be configured to form a connection according to the invention between the rolling tube 13 of the air spring unit 10 and the damper tube 12 of the damper unit 11. The torsion element 16 is essentially annular, the torsion element 16 being shown half cut away. On the inside the recesses 17 are shown, in which the supporting geometries 14 according to FIG. 2 can fit. The torsion element 16 in the form shown is in an uninstalled, unloaded state, and it can be seen that the recesses 17 are already made in the basic geometric structure of the torsion element 16.

(12) The torsion element 16 has a rubber-elastic material, for example a nitrile rubber, which is produced by injection moulding. On the inside the torsion element 16 has a shape-stabilising core body 18, which is produced from a hard material, for example a hard plastic material or a metal material, and is formed running around with the torsion element 16 in an annular manner.

(13) On the outside the torsion element 16 has an essentially conical contour, which is adapted to the conical shape of the radially expanded end 15 of the rolling tube 13. At the end of the torsion element 16, at which the conical outer contour has a smaller diameter, the torsion element 16 has a sealing lip 20, which is formed in one piece from the rubber-elastic material. With the sealing lip 20 the torsion element 16 can perform a sealing function against the inside of the rolling tube 13. The sealing effect between the torsion element 16 and the damper tube 12, in particular the supporting geometries 14, is achieved by the interior press fit of the torsion element 16. The radially expanded end 15 can either merely sit on the outside of the torsion element 16 or the torsion element 16 is vulcanised or for example adhesively bonded onto the inside of the radially expanded end 15 of the rolling tube 13.

(14) FIG. 4 shows a side view of the arrangement of the torsion element 16 on the supporting geometries 14 of the damper tube 12, and the torsion element 16 has a sealing lip 20 on the outside. The cross-sectional view of the torsion element 16 on the supporting geometries 14 of the damper tube 12 according to section line A-A is shown in FIG. 5 below.

(15) FIG. 5 shows a cross-sectional view of the arrangement of the torsion element 16 on the damper tube 12 according to section line A-A. The damper tube 12 is formed by way of example with three supporting geometries 14, which are formed as radially outwardly curved mouldings. To accommodate the supporting geometries 14 and thus to produce a form-fitting geometry, the torsion element 16 has recesses 17, in which the supporting geometries 14 fit. The form fit between the recesses 17 and the supporting geometries 14 allows the transmission of torques between the torsion element 16 and the damper tube 12 about the longitudinal axis 22, as a result of which a rotation of the damper unit 11 with respect to the air spring unit 10 is produced in the elastic region of the torsion element 16, as shown in FIG. 1. The elastic, torque-transmitting rotation of the damper unit 11 with respect to the air spring unit 10 can be an angle of less than 10, preferably of less than 5, and particularly preferably of less than 1 about the longitudinal axis 22.

(16) According to a further embodiment, the radially expanded end 15 of the rolling tube 13 can have a corrugated shape, which is formed in a complementary manner to the supporting geometries 14 in the damper tube 12. For example, the radially expanded end 15 can have three wave-like, outwardly formed bulges, which are made in the radially expanded end 15 in the radial positions in which the supporting geometries 14 are also situated. The torsion element 16, when in the mounted state, can press elastically into the outwardly formed bulges in the end 15, as a result of which a form fit between the torsion element 16 and the rolling tube 13 is likewise created in the direction of rotation.

(17) The invention is not limited in its implementation to the above-specified preferred exemplary embodiment. Rather, a number of variants are conceivable, which make use of the solution described even with fundamentally differently designed configurations. All the features and/or advantages given in the claims, description or drawings, including design details or spatial arrangements, can be essential to the invention both alone and in a wide variety of combinations.

LIST OF REFERENCE SYMBOLS

(18) 1 Suspension strut 10 Air spring unit 11 Damper unit 12 Damper tube 13 Rolling tube 14 Supporting geometry 15 Radially expanded end 16 Torsion element 17 Recess 18 Core body 19 Pressure chamber 20 Sealing lip 21 Supporting shoulder 22 Longitudinal axis 23 Connecting bolts 24 Fastening eye 25 Piston rod