AU2017206408A1

AU2017206408A1 - Pneumatic spring for axles of vehicles with air suspension

Info

Publication number: AU2017206408A1
Application number: AU2017206408A
Authority: AU
Inventors: Roland Berghaus; Martin Fleischhauer; Lisa HASENBURG; Bernhard Walter
Original assignee: BPW Bergische Achsen KG
Current assignee: BPW Bergische Achsen KG
Priority date: 2016-01-14
Filing date: 2017-01-05
Publication date: 2018-08-02
Anticipated expiration: 2037-01-05
Also published as: PL3403000T3; RU2731041C2; RU2018129354A3; EP3403000A1; EP3403000B1; RU2018129354A; ES2928121T3; WO2017121425A1; AU2017206408B2; DE102016100581A1

Abstract

The invention relates to a pneumatic spring (1) for axles of vehicles with air suspension, comprising a plunger piston (5) which can be fixed to an axle, an upper closure cover (2) which can be fixed to the vehicle and which comprises rolling bellows (3) secured to the cover, and a bead (32) which is formed on the rolling bellows (3) and which is fixed to the upper face (13) of the plunger piston (5) by a ring (6). The aim of the invention is to allow a simple, non-detachable, and pressure-tight fixation of the rolling bellows (3) to the plunger piston (5) with a pneumatic spring (1) and to allow a fully automatic assembly. According to the invention, this is achieved in that the ring (6) is secured against the plunger piston (5) via a rotational mechanism formed on the ring (6) and on the plunger piston (5).

Description

(57) Zusammenfassung: Die Erfindung betrifft eine Luftfeder (1) fur Achsen luftgefederter Fahrzeuge mit einem achsseitig festlegbaren Tauchkolben (5), einem fahrzeugseitig festlegbaren oberen Abschlussdeckel (2) mit einem daran befestigten Rollbalg (3), und mit einem an dem Rollbalg (3) ausgebildeten Wulst (32), der an der Oberseite (13) des Tauchkolbens (5) durch einen Ring (6) fixiert ist. Um eine einfache, unlosbare und druckdichte Befestigung des Rollbalgs (3) am Tauchkolben (5) mit einer Luftfeder (1) zu ermoglichen und eine vollautomatische Montage zu erlauben, wird erfindungsgemaB vorgeschlagen, den Ring (6) fiber einen, einerseits an dem Ring (6) und andererseits an dem Tauchkolben (5) ausgebildeten Drehmechanismus, gegen den Tauchkolben (5) zu sichem.

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Veroffentlicht:

— mit internationalem Recherchenbericht (Artikel 21 Absatz 3)

BPW Bergische Achsen KG

Ohlerhammer

51674 Wiehl

UC/do/mw

05.01.2017 'Pneumatic Spring for Axles of Vehicles with Air Suspension'

The invention concerns a pneumatic spring for axles of vehicles with air suspension, with a plunger piston which can be fixed to an axle, an upper closing cover which can be fixed to the vehicle with rolling lobe attached thereto, and a bead which is formed on the rolling lobe and fixed to the upper face of the plunger piston by a ring.

Pneumatic springs generally consist of an elastic rolling lobe filled with compressed air, which is usually fixed at the top to a closing cover arranged on the vehicle and at the bottom to a plunger piston. When the pneumatic spring is compressed, the plunger piston penetrates into the volume of the rolling lobe. On the axle side, the plunger piston is fixed either directly to the vehicle axle or to the longitudinal control arm guiding the vehicle axle. Furthermore, so-called buffer elements for damping impacts may be arranged between the rolling lobe and the plunger piston.

The rolling lobe is filled with air via a pressure valve located on the upper closing cover. At each of its upper and lower ends, the rolling lobe has a bead which may have a vulcanized wire core. These beads are attached to the upper closing cover of the pneumatic spring and to the plunger piston.

The prior art discloses various possibilities for fixing the beads of the rolling lobe to the closing cover and to the plunger piston. The rolling lobe beads are normally attached to the closing cover in that the beads are enclosed in flanged rims of the closing cover.

To fix the rolling lobe to the rolling piston, DE 10 2012 104 964 A1 discloses a catch solution. In the region of its cover plate, the rolling piston has an inwardly tapering cavity for a conical sealing seat with a bead-like bulge of the rolling lobe. The trapezoid rolling lobe bead is axially secured by means of a groove, running circumferentially along the inner leg of the cavity of the plunger piston in the region of its cover plate, and a clamping ring which sits in the groove by form fit. The fixing of the rolling lobe bead, by clamping of a clamping ring in the groove, is under permanent load, such as for example by a vertical oscillating motion, and susceptible to material wear due to the friction forces occurring between the clamping ring

001

-2and the rolling lobe bead. This may lead to material loss and the associated breakout of the rolling lobe bead from the cavity of the conical sealing seat.

A fixing of the rolling lobe to the plunger piston by means of threaded arrangements is disclosed in DE 41 15 028 C2. This discloses a pneumatic spring consisting of a rolling lobe and a plunger piston, wherein at its open end, the rolling lobe has conical sealing beads which are connected to threaded portions situated on a conical sealing seat of the plunger piston. Mounting such an arrangement calls for a complex twisting of the rolling lobe, which must therefore be performed manually, against the threaded portions attached to the cone. Furthermore, such a twist connection of the threaded portions and the rolling lobe under permanent load may lead to damage to the rolling lobe.

The invention is based on the object of creating a simple, non-releasable and also pressuretight mounting of the rolling lobe on the plunger piston, which is also suitable for fully automatic attachment of the rolling lobe to the plunger piston.

This object is achieved by a pneumatic spring for axles of vehicles with air suspension, with the features given in claim 1.

Such a pneumatic spring consists mainly of a rolling lobe which is mounted on a closing cover attached to the vehicle, the main body of which lobe is filled with air and has beads at its upper and lower end, and with a plunger piston, the lower end of which is attached to the axle. The upper end of the rolling lobe is attached to the closing cover, while the bead on the lower end of the rolling lobe is secured to the upper face of the plunger piston by a ring. Such a fixing is achieved via a rotational mechanism formed on the ring and on the plunger piston.

The fixing of the rolling lobe and the plunger piston, secured by a ring as described here, is distinguished by a simple rotational mechanism which simultaneously connects together several components of the pneumatic spring in one working step, for example by mutual clamping or bracing.

The rotational mechanism, which achieves the connection between the rolling lobe and the plunger piston via a ring, is characterized by a thread running between the ring and the plunger piston. The thread consists of an inner thread running along the cylindrical inner face of the ring, and an outer thread situated on the casing surface of a round protrusion of the plunger piston. Such a thread, molded directly onto the plunger piston, allows the omission of additional connecting elements - apart from the ring - for connecting the plunger piston and

001

-3the rolling lobe. This leads firstly to a material saving and secondly to a simplified coupling of the two components. The plunger piston, with its protrusion located on its upper face and its outer thread, may for example be produced in one step in an injection molding process.

An additional feature of the ring securing the rolling lobe to the plunger piston is the nonreleasable toothed engagement of the ring with the plunger piston. Such a toothed engagement may for example be achieved by catch elements located on the side of the ring facing the plunger piston, and catch elements arranged on the side of the plunger piston facing the closing cover. In one embodiment, the catch elements, extending up or down from the respective surface, have a chamfer. Such a toothing mechanism with chamfered catch elements has the advantage that it allows only a unidirectional rotational movement, and hence guarantees a non-releasable rotational fixing. In the embodiment according to the invention, this leads to a permanent locking of rolling lobe and plunger piston, with the decisive advantage that no additional connecting elements are required, such as the clamping rings or thread portions shown in the prior art.

A further advantage of the locking mechanism according to the invention is achieved in that the ring also surrounds, as well as the rolling lobe and the plunger cover, a buffer element arranged between the plunger piston and the upper closing cover. This is achieved via a radial widening, oriented towards the casing surface of the pneumatic spring, on the side of the buffer element facing the plunger piston, and by a radial widening of the ring oriented towards the inside of the pneumatic spring and facing the upper closing cover, wherein the two radial widenings overlap. In this way, no further or autonomous locking components are required for fixing the buffer element to the rolling lobe or plunger piston.

The buffer element preferably consists of a rubber-like thermoplastic material. The base material of the rolling lobe and plunger piston, made from rubber, also allows fully automatic production of the main components of the pneumatic spring.

The arrangement of the ring inside the pneumatic spring allows the ring underside to radially overlap the lower bead of the rolling lobe, and thus secure the rolling lobe. In this case too, no further material components are required for fixing the rolling lobe bead. Rolling lobe beads normally consist of a wire ring vulcanized into the plastic of the rolling lobe, offering additional stability against clamping forces.

The clamping of the main components of the pneumatic spring - in particular the rolling lobe, plunger piston and buffer element - by the ring constitutes a simple, non-releasable, material17 001

-4saving and stable embodiment of a rotational fixing, and also a bracing of the main components of the pneumatic spring. The non-releasable rotational fixing counters the horizontally acting shear forces, while the clamping of the lower rolling lobe bead under the ring counters the substantially vertically acting forces. Also, it is thus possible to produce the main components of the pneumatic spring fully automatically, for example in the injection molding process, and clamp these together in just one step, whereby complex working steps and material costs can be saved.

Further details and advantages of the invention arise from the description below and the associated drawings, which show an exemplary embodiment of a pneumatic spring according to the invention. The drawings show:

Fig. 1 a perspective view of an embodiment of a pneumatic spring on an axle with air suspension;

Fig. 2 a section along a longitudinal axis of a pneumatic spring, with a closing cover attached to the vehicle, a rolling lobe attached thereto, a plunger piston attached to the axle, a buffer element, and a ring clamping the rolling lobe, plunger piston and buffer element;

Fig. 3 an exploded view of the pneumatic spring with the individual components shown in figure 1;

Fig. 4 a diagrammatic cross-section through the plunger piston;

Fig. 5 a detail view of an extract of a ring of catch elements arranged on the plunger piston;

Fig. 6 a perspective view of the underside of the ring clamping the rolling lobe and plunger piston;

Fig. 7 a detail view of an extract of a catch element arranged on the lower inside of the ring.

The pneumatic spring 1 according to figure 1 is attached by its lower face to a vehicle axle 4. Figure 2 shows a cross-section through a pneumatic spring 1, which consists of a closing cover 2 attached to a vehicle, e.g. to a vehicle chassis, a rolling lobe 3 attached thereto, a

001

-5plunger piston 5 attached to the vehicle axle 4 or to the longitudinal control arm of the vehicle axle, a ring 6 securing the rolling lobe 3 to the plunger piston 5, and a buffer element 10 arranged between the closing cover 2 and the plunger piston 5. The buffer element 10 is arranged above the plunger piston 5.

The closing cover 2 attached to the vehicle carries on its upper face 11, facing the vehicle, a compressed air connection 20 and a screw thread 21 pointing towards the vehicle, and is mounted rigidly on the chassis by retaining bolts 22. On its outside, the closing cover 2 has radially running enclosure pockets 30 which terminate in the direction of the interior of the pneumatic spring. The upper end of the rolling lobe 3 facing the closing cover 2 is received in the enclosure pockets 30.

The annular ends of the rolling lobe on both the upper face 12 and the lower face 14 of the rolling lobe 3 take the form of upper annular beads 31 and lower annular beads 32. The beads 31 on the upper face 12 of the rolling lobe are enclosed in the enclosure pockets 30 of the closing cover 2, e.g. by rim flanging.

The rolling lobe 3 at least partially surrounds the casing surface of the plunger piston 5 attached to the axle, on which surface it rolls during suspension compression. As a result, the plunger piston 5 plunges into the volume of the rolling lobe 3 during the compression process. The side of the plunger piston 5 facing the vehicle axle 4 is connected via a thread 33 and a corresponding threaded bolt 23 to the vehicle axle 4 or to a control arm of the vehicle. On its upper face 13 facing the closing cover 2 of the pneumatic spring 1, the plunger piston 5 has a protrusion 35 running axially relative to the longitudinal axis A.

The interior of the plunger piston 5 is formed by cavities 40 and partly by solid material. Weblike connecting elements 41 run from the plunger piston casing 42 radially relative to its longitudinal axis A, and protrude into the interior of the plunger piston 5 along the longitudinal axis A, whereby the cavities 40 are delimited from each other and formed as segments.

The inner sides of the axial protrusion 35 of the plunger piston 5, on the upper face 13 of the plunger piston 5 facing the closing cover 2, surround a partial length of a casing surface 43 of a buffer element 10 arranged between the plunger piston 5 and the closing cover 2. In the embodiment shown here, the radius of the buffer element 10 is smaller than the radius of the protrusion 35 of the upper face 13 of the plunger piston 5. The inner region of the buffer element 10 is composed of the buffer element cavities 50 and solid material components,

001

-6which are separated by webs 51 running radially relative to the longitudinal axis A of the pneumatic spring 1.

The protrusion 35 on the upper face 13 of the plunger piston 5 is surrounded externally by the ring 6. Also, a part length of the buffer element 10 is surrounded by the ring 6. The collar 52, protruding into the interior of the pneumatic spring 1 and running radially relative to the longitudinal axis A, lies at least partially on a collar 53 of the buffer element 10 running radially relative to the longitudinal axis A and oriented towards the casing surface 44 of the pneumatic spring 1. At this point, the collar 52 of the ring 6 protruding into the interior of the pneumatic spring 1 has an inner radius which is smaller than the outer radius of the collar 53 on the buffer element 10, both in relation to the longitudinal axis A of the pneumatic spring 1. Furthermore, on its underside 60, the ring 6 radially overlaps the annular lower bead 32 of the rolling lobe 3 and encloses this in a pocket 61.

Figure 2 also shows clearly that the underside 60 of the ring 6 facing the vehicle axle at least partially radially overlaps the lower annular bead 32 of the rolling lobe 3. The upper face 13 of the plunger piston 5 has a depression 62, running around the longitudinal axis A of the pneumatic spring 1 in the form of an annular channel, in which the lower annular bead 32 of the rolling lobe 3 sits by form fit. The rolling lobe 3 is fixed at its lower face 14 by the partial overlap by the underside 60 of the ring 6 over the lower bead 32 of the rolling lobe 3.

As also shown in figure 3, the outside 63 of the protrusion 35 of the plunger piston 5, pointing in the direction of the closing cover 2, is provided with an outer thread 64. The corresponding counter-thread 65 is formed on the inside of the ring 6, surrounding the protrusion 35 and buffer element 10. With its inner thread 65, the ring 6 surrounds the outer thread 64 of the protrusion 35 of the plunger piston 5, and also at least partially encloses the buffer element

10.

Furthermore, the upper face 13 of the plunger piston 5, in the region of an end face 18 of the protrusion 35 running radially and pointing towards the closing cover 2, has an annular arrangement of catch elements 71.

The annular arrangement of lower catch elements 71 on the end face 18 of the protrusion 35 is also shown in figure 4 and figure 5. This arrangement is an annular succession of lower catch elements 71, with a chamfer 72 of the individual catch elements 71 running towards the vehicle. As figure 5 shows particularly clearly, the tips 75 of the individual catch elements 71, and the troughs 76 of the catch elements 71, form two planes which establish the position of

001 -7the catch elements 71 relative to the longitudinal axis A of the pneumatic spring. It is particularly important here that all tips 75 have the same position relative to the longitudinal axis A of the pneumatic spring 1, and all troughs 76 have the same position relative to the longitudinal axis A of the pneumatic spring 1. Such an annular arrangement of catch elements

71 is preferably produced economically from a single component.

For the toothed engagement of the lower face 17 of the collar 52 of the ring 6 with the protrusion 35 of the plunger piston 5, the collar 52 of the ring 6, from its lower face, is equipped with at least two symmetrically arranged catch elements 72, preferably however with four symmetrically arranged catch elements 72.

As figures 6 and 7 show, the upper catch elements 72 also have a chamfer 74 which runs in the direction of the vehicle axle. When the ring is attached to the plunger piston 5, not only does the inner thread 65 of the ring 6 engage with the outer thread 64 of the protrusion 35 of the plunger piston 5, but also the catch elements 72 situated on the lower face 17 of the collar 52 of the ring 6 engage with the catch elements 71 situated on the end face 18 of the protrusion 35 of the plunger piston 5. The lower catch elements 71 and the upper catch element 72 thus create a non-releasable connection with unilateral locking.

In a further embodiment, such a connection may also be implemented via a rotational mechanism in the manner of a bayonet closure between the ring 6 and the upper face 13 of the plunger piston.

001

-8List of Reference Signs

Pneumatic spring

Closing cover

Rolling lobe

Vehicle axle

Plunger piston

Ring

Buffer element

Upper face

Lower face

End face

Compressed air connection

Screw connection

Retaining bolt

Threaded bolt

Enclosure pocket

Upper annular bead

Lower annular bead

Thread

Protrusion

Cavity

Connecting element

Plunger piston casing

Casing surface

Buffer element cavity

Web

Collar (ring)

Collar (buffer element)

Ring underside

001

-9Pocket Depression Outside Outer thread Inner thread Catch element Catch element Chamfer Chamfer

Longitudinal axis

001

Claims

Claims

1. A pneumatic spring (1) for axles of vehicles with air suspension, with a plunger piston (5) which can be fixed to an axle, an upper closing cover (2) which can be fixed to the vehicle with a rolling lobe (3) attached thereto, and a bead (32) which is formed on the rolling lobe (3) and which is fixed to the upper face (13) of the plunger piston (5) by a ring (6), characterized in that the ring (6) is secured against the plunger piston (5) via a rotational mechanism formed firstly on the ring (6) and secondly on the plunger piston (5).
2. The pneumatic spring as claimed in claim 1, characterized in that the rotational mechanism is a thread (34) between the ring (6) and the plunger piston (5).
3. The pneumatic spring as claimed in claim 2, characterized in that the thread (34) consists of an outer thread (64) and an inner thread (65), wherein the outer thread (64) is arranged on the plunger piston (5) and the inner thread (65) on the ring (6).
4. The pneumatic spring as claimed in claims 1 to 3, characterized in that the outer thread (64) is located on a round protrusion (35) molded onto the upper face (13) of the plunger piston (5).
5. The pneumatic spring as claimed in claim 1, characterized in that the side of the ring (6) facing away from the closing cover (2) and the side of the plunger piston (5) facing the closing cover (2) are toothed, whereby the toothing locks unilaterally.
6. The pneumatic spring as claimed in any of claims 1 to 5, characterized in that the side of the ring (6) facing away from the closing cover (2) consists of several upper catch elements (72) arranged radially symmetrically, and the side of the plunger piston (5) facing the closing cover (2) consists of several mutually adjacent lower catch elements (71), wherein the upper catch elements (72) have a chamfer (74) in the direction of the upper face (13) of the plunger piston (5), and the lower catch elements (71) have a chamfer (73) in the direction of the lower face (16) of the closing cover (2).
7. The pneumatic spring as claimed in claim 6, characterized in that the upper catch elements (72) are formed on the lower face (17) of a collar (52) of the ring (6) protruding towards the longitudinal axis (A) of the pneumatic spring (1), and the lower catch

17 001

- 11 25 elements (71) are formed on the end face (18) of a round protrusion (35) of the plunger piston (5).
8. The pneumatic spring as claimed in any of the preceding claims, characterized in that

5 the ring (6) surrounds a buffer element (10) situated on the plunger piston (5) and facing the closing cover (2).
9. The pneumatic spring as claimed in claim 8, characterized in that the buffer element (10) is made of a rubber or a thermoplastic material.
10. The pneumatic spring as claimed in claims 8 and 9, characterized in that the buffer element (10) has a radial collar (53) oriented towards the casing surface (44) of the pneumatic spring (1), and the ring (6) has a radial collar (52) oriented towards the longitudinal axis (A) of the pneumatic spring (1), wherein the collar (52) of the ring (6)

15 overlaps the collar (53) of the buffer element (10) circumferentially.
11. The pneumatic spring as claimed in any of the preceding claims, characterized in that the underside (60) of the ring (6) facing the plunger piston (5) radially overlaps the lower bead (32) of the rolling lobe (3).
12. The pneumatic spring as claimed in any of claims 1 to 11, characterized in that the ring (6) secures the plunger piston (5), the buffer element (10) and the lower bead of the rolling lobe (3) non-releasably, preferably clamping them together.
13. The pneumatic spring as claimed in any of claims 1 to 12, characterized in that the plunger piston (5), with the protrusion (35) located on its upper face and the outer thread (64), is produced in one step by injection molding.

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