Air spring unit having a divided outer guide

Abstract

An air spring unit for a chassis of a motor vehicle, includes an air spring cover and an air spring piston, wherein an airtightly secured rolling bellows made of elastomer material partially delimits a working chamber between the air spring cover and the air spring piston, which working chamber can be filled with compressed air, wherein the rolling bellows is surrounded by a divided, sleeve-shaped outer guide having a first outer guide part and a second outer guide part.

Claims

1. An air spring unit comprising: an air spring cover an air spring piston, and wherein an airtightly secured rolling bellows made of elastomer material partially delimiting a working chamber between the air spring cover and the air spring piston, which working chamber can be filled with compressed air, wherein the rolling bellows is surrounded by a divided, sleeve-shaped outer guide having a first outer guide part and a second outer guide part, the first outer guide part separate from the second outer guide part by a space, and wherein the rolling bellows forms a torsion fold in the space between the first and the second outer guide part.

2. The air spring unit as claimed in claim 1, wherein the rolling bellows is designed as an axial bellows in the region of the torsion fold.

3. The air spring unit as claimed in claim 1, wherein the rolling bellows is designed as a hybrid bellows having a cross ply bellows in the region of the first outer guide part and having an axial bellows in the region of the second outer guide part.

4. The air spring unit as claimed in claim 1, wherein the first outer guide part can be secured on the rolling bellows by a first inner locking ring and/or the second outer guide part can be secured thereon by a second inner locking ring.

5. The air spring unit as claimed in claim 1, wherein the first outer guide part and/or the second outer guide part are adhesively bonded to the rolling bellows.

6. The air spring unit as claimed in claim 1, wherein the first outer guide part is provided on the air spring piston in a region of a first rolling fold of the rolling bellows.

7. The air spring unit as claimed in claim 1, wherein the second outer guide part is provided on the air spring cover in a region of a second rolling fold of the rolling bellows.

8. The air spring unit as claimed in claim 1, wherein the second outer guide part jointly surrounds a part of the air spring cover and a part of the rolling bellows.

9. The air spring unit as claimed in claim 1, wherein the rolling bellows is secured on the air spring cover by a clamping area, wherein the second outer guide part is arranged between the clamping area and the first outer guide part.

10. The air spring unit as claimed in claim 1, wherein the air spring unit comprises an integrated shock damper, wherein the second outer guide part remains aligned substantially parallel to the shock damper during the inward deflection of the air spring unit.

11. A chassis for a motor vehicle, comprising an air spring system, the air spring system comprising the air spring unit as claimed in claim 1.

12. An air spring unit comprising: an air spring cover an air spring piston, and wherein an airtightly secured rolling bellows made of elastomer material partially delimiting a working chamber between the air spring cover and the air spring piston, which working chamber can be filled with compressed air, wherein the rolling bellows is surrounded by a divided, sleeve-shaped outer guide having a first outer guide part and a second outer guide part, wherein the rolling bellows forms a torsion fold between the first and the second outer guide part, wherein the rolling bellows is designed as an axial bellows in the region of the torsion fold, and wherein the rolling bellows is designed as an extended hybrid bellows having a cross ply bellows in the region of the first and the second outer guide part, wherein the rolling bellows is designed as an axial bellows in the region of the torsion fold.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further preferred embodiments of aspects of the invention will emerge from the subclaims and the following description of exemplary embodiments with reference to the figures.

(2) In the figures:

(3) FIG. 1 shows a first exemplary air spring unit,

(4) FIG. 2 shows a second exemplary air spring unit, and

(5) FIG. 3 shows a third exemplary air spring unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) FIG. 1 shows a first exemplary air spring unit 1 having an air spring 5 and an integrated shock damper 22. On the one hand, air spring unit 1 can be secured on a motor vehicle body by means of an air spring cover 2 and, on the other hand, it can be secured on a wheel carrier of the motor vehicle chassis by means of shock damper 22, whereby the motor vehicle is sprung and damped.

(7) Air spring 5 comprises a rolling bellows 6 made of elastomer material, wherein rolling bellows 6, together with air spring cover 2 and an air spring piston 3, at least partially delimits an airtight working chamber 12 that can be filled with compressed air. At its axial lower end, rolling bellows 6 is airtightly connected to air spring piston 3 by means of a first clamping ring 13 and, at its axial upper end, is airtightly connected to air spring cover 2 by means of second clamping ring 14.

(8) In the case of relative movements in the axial direction of the air spring unit 1 between the air spring cover 2 and the air spring piston 3, rolling bellows 6 rolls on the rolling contact surface of the concentric air spring piston 3, forming a first rolling fold 10. Rolling bellows 6 furthermore forms a second rolling fold 11 on the air spring cover 2, said fold rolling on an annular wedge 4 and acting as a cardanic bearing. By means of the shape of the annular wedge 4, various rolling contours for second rolling fold 11 can be achieved, influencing the spring behavior or even the effect as a cardanic bearing. In addition to acting as a cardanic bearing, second rolling fold 11 also serves partially to absorb torsion when the air spring 5 rotates.

(9) According to the example, the outer guide is embodied as a separate two-part outer guide having a first, lower outer guide part 16 and a second, upper outer guide part 17. An outer guide segmented into more than two parts is likewise conceivable. First outer guide part 16 surrounds first rolling fold 10 and is arranged in the region of the air spring piston 3, while second outer guide part 17 surrounds second rolling fold 11 and is arranged in the region of the air spring cover 2. First outer guide part 16 is secured on the rolling bellows 6 by means of a first inner locking ring 18 and second outer guide part 17 is secured thereon by means of a second inner locking ring 19. Both outer guide parts 16, 17 can also be adhesively bonded to the rolling bellows 6. Outer guide parts 16, 17 are preferably manufactured from aluminum or a steel, but can also be manufactured from a plastic.

(10) At the same time, rolling bellows 6 is configured as a hybrid bellows according to the example. Thus, the first rolling fold 10 and a lower part of the rolling bellows 6 in the region of the first outer guide part 16 is embodied as a cross ply bellows 7, while second rolling fold 11 and an upper part of the rolling bellows 6 in the region of the second outer guide part 17 is embodied as an axial bellows 8. In the upper end region of the first outer guide part 16 or in the clamping region, by means of a first inner locking ring 18, there is a region of overlap 9 between cross ply bellows 12 and axial bellows 13 of the rolling bellows 6.

(11) Rolling bellows 6 can also be designed as an extended hybrid bellows. In this case, first rolling fold 10 and a lower part of the rolling bellows 6 in the region of the first outer guide part 16 is embodied as a cross ply bellows 7, and second rolling fold 11 and an upper part of the rolling bellows 6 in the region of the second outer guide part 17 is likewise embodied as a cross ply bellows. Only torsion fold 15 is embodied as an axial bellows. Accordingly, the regions of overlap between the cross ply bellows and the axial bellows are provided in the clamping regions, by means of inner locking rings 18 and 19. Thus, a pliable axial bellows with effective torsion absorption and improved cardanic deflection is advantageously used for torsion point TP, wherein the remainder of the rolling bellows 6 is embodied as a robust cross ply bellows.

(12) In the free region between the two outer guide parts 16, 17, rolling bellows 6 forms a torsion fold 15 according to the example, wherein torsion fold 15 is embodied as an axial bellows 8. Thus, an advantageous torsion point TP is created in the central region of the air spring 5, said torsion point enabling effective torsion absorption in the case of rotary movements of the air spring 5 by virtue of the embedded axial reinforcements.

(13) Shock damper 22 is integrated into air spring piston 3, wherein air spring piston 3 surrounds a damper tube 23 of the shock damper in a hollow cylinder shape and is secured on said tube.

(14) Shock damper 22 furthermore comprises a damper rod 24 and is supported centrally in a bearing socket 30 of the air spring cover 2 by means of damper bearings 25. An additional spring 26 resting against the air spring cover 2 is arranged below the damper bearing 25 and in the working chamber 12 of the air spring 5, wherein additional spring 26 surrounds the damper rod 24 in a hollow cylinder shape and serves as a stop buffer for damper tube 23. At an upper side of the air spring unit 1 are fastening elements 29. A closure cap 27 is disposed above the damper rod 24 and the damper bearing 25. An air connection 28 is disposed above the closure cap 27 and provides a means to connect the air spring unit 1 with an air supply (not shown).

(15) Torsion fold 15 also advantageously acts as a cardanic bearing. As the air spring pivots, the lower rolling fold is pressed against the air spring piston as in the prior art, as a result of which a force is exerted on the shock damper. The divided outer guide according to the example significantly reduces the pressure of the first rolling fold 10 against air spring piston 3. During inward deflection, both outer guide parts 16, 17 pivot at different angles to one another, as a result of which first rolling fold 10 is pressed only slightly or not at all against air spring piston 3, and therefore disadvantageous transverse forces do not act on shock damper 22.

(16) To protect the rolling folds against contamination, a corrugated bellows 20 is secured on the lower end of the first outer guide part 16, protecting the first rolling fold 10. A further protective bellows 21 is secured on the air spring cover 2 and on the upper end of the second outer guide part 17 and thus protects the second rolling fold 11.

(17) FIG. 2 shows a second exemplary air spring unit 1, which substantially corresponds in respect of the divided outer guide to the air spring unit in FIG. 1 and differs in the embodiment of the air spring cover 2.

(18) Air spring cover 2 is shaped as a large-volume cover and can comprise several parts. In this exemplary embodiment, rolling bellows 6 is secured on air spring cover 2 by means of second clamping ring 14, without the formation of an upper rolling fold. Rolling bellows 6 rolls on the air spring piston 3 by means of rolling fold 10. First outer guide part 16 surrounds rolling fold 10 and is arranged in the region of the air spring piston 3, while second outer guide part 16 is provided radially around the clamping area 14 and surrounds an upper part of the rolling bellows as well as a lower part of the air spring cover 2. That is to say that the second outer guide part rests externally on the air spring cover 2, on the one hand, and on the rolling bellows 6, on the other hand. In this fastening variant, there is no inner locking ring.

(19) As in the illustrative embodiment shown in FIG. 1, the torsion fold 15 with torsion point TP, which additionally acts as a cardanic bearing, forms between the two outer guide parts 16, 17. At the same time, as in FIG. 1, rolling bellows 6 is designed as a hybrid bellows or, alternatively, can be designed as an extended hybrid bellows.

(20) A third exemplary air spring unit 1 is shown in FIG. 3, differing in respect of the design of the second outer guide part 17 from the air spring unit in FIG. 2. In this fastening variant, second outer guide part 17 is secured by means of second inner locking ring 19 and is provided below the clamping area 14.

LIST OF REFERENCE SIGNS

(21) 1 Air spring unit 2 Air spring cover 3 Air spring piston 4 Annular wedge 5 Air spring 6 Rolling bellows 7 Cross ply bellows 8 Axial bellows 9 Region of overlap 10 First rolling fold 11 Second rolling fold 12 Working chamber 13 First clamping ring 14 Second clamping ring 15 Torsion fold 16 First outer guide part 17 Second outer guide part 18 First inner locking ring 19 Second inner locking ring 20 Corrugated bellows 21 Protective bellows 22 Shock damper 23 Damper tube 24 Damper rod 25 Damper bearing 26 Additional spring 27 Closure cap 28 Air connection 29 Fastening element 30 Bearing socket TP Torsion point