DE102008055512A1 - Air spring for e.g. towing vehicle, has fastening bead whose lower side is provided against shoulder of piston, and circulating sealing rib arranged on shoulder between cone seat and rolling edge of piston - Google Patents

Abstract

The air spring (1) has rolling bellows (3) including a fastening bead (4) with a bead core (5) and made of elastomer material. The bead core is provided at an end of the rolling bellows facing a rolling piston (2), where piston is made of plastic. A conical sealing surface of the fastening bead is provided against a cone seat (7) of the piston, where a lower side of the fastening bead is provided against a shoulder of the piston. A circulating sealing rib is arranged on the shoulder between the cone seat and a rolling edge of the piston.

Description

The The invention relates to an air spring for commercial vehicles with a rolling piston made of plastic and a rolling bellows made of elastomeric material, wherein the Rolling bellows at its, the rolling piston end facing a Befestigungswulst having a bead core, which with its conical sealing surface on a Conical seat of the rolling piston and with its underside on the shoulder of the rolling piston sealingly applied.

such Air springs are known per se and in great variety in commercial vehicles, For example, in towing vehicles and trailers, in use.

The Attachment of the bellows on the rolling piston is usually done by simply pushing on the mounting bead of the rolling bellows on the conical seat of the rolling piston. The mounting bead is usually this with at least one embedded, tensile bead core or annular body or Pierce core made of steel or steel wire reinforced and is under the effect the internal pressure of the rolling bellows at the associated conical seat of the rolling piston and the shoulder of the rolling piston.

alternative can the connection of the bellows on the rolling piston also over a screwed clamping plate made, which the rolling bellows on the Rolling piston fixed. In this attachment, however, the internal volume of the rolling piston for used the screw, so this is no longer for a minimization the natural frequency available stands. An air spring with such a connection of the rolling bellows on the rolling piston is not the subject of the present invention be.

As is known, exists the rolling piston made of plastic. This will prevent corrosion protected and has an advantage over a conventional one Rolling piston made of Me tall a lower weight. It has, however shown that such air springs are often not tight with temperature fluctuations are.

outgoing From this prior art, the invention is based on the object a generic air spring to further develop such that a tight connection of the bellows is ensured on the rolling piston even with temperature fluctuations.

These The object is achieved by the Characteristics of claim 1 solved.

According to the invention is on the shoulder between conical seat and the rolling edge of the rolling piston arranged at least one circumferential sealing rib.

It has been shown to make this an airtight connection between Rolling bellows and rolling piston at any expected operating temperature the air spring can be reached. Such a connection is effective and cost-effective produced.

at a usual one Air spring with a rolling piston made of plastic, to which the connection of the bellows only over a cone-shaped Sealing surface of a Fixing bead with bead core made of steel, can the tightness the Konussitz construction can not be guaranteed, because the Plastic rolling piston and the fixing bead with steel core expand differently with temperature fluctuations. This is up the coefficients of expansion which are different by a factor of ten attributed to plastic and steel.

at a rolling bellows with an end fastening bead and metallic Bead core presses the internal pressure in the air spring, although usually the Befestigungswulst in the cone-shaped sealing surface or in the conical seat of the rolling piston, however, can change in temperature the diameter of the cone seat made of plastic and the metal core trained Befestigungswulstes due to the different Coefficient of linear expansion of plastic and metal change so much that at a low Internal pressure in the air spring sealing the cone seat no longer guaranteed is.

Here creates the embodiment of the invention Remedy.

at the air spring according to the invention is the rolling bellows by its own weight and within the Air spring acting internal pressure on the sealing rib pressed. in the Contrast to the seal over the conical sealing surface or the conical seat, this first affects the surface of Sealing rib as a sealing surface.

The change in length of the bead core has on this surface only a very small influence.

In addition, will the rolling bellows with increasing pressure on the sealing surface of the Sealing rib pressed.

temperature fluctuations remain without influence on the tightness of the air spring.

Advantageous can in this connection of the rolling bellows on the rolling piston the Inner volume of the rolling piston remain free. In addition, can be the rolling bellows relatively easily separate from the rolling piston, wherein the Rolling piston is reusable.

A development of the invention provides that the sealing rib is molded onto the shoulder of the rolling piston.

Preferably is the sealing rib in cross-section V-, semi-oval, or semicircular.

following the invention will be explained with reference to two embodiments, the are shown in the drawing. In this show

1 a first and 2 a second embodiment, namely:

1a and 2a in each case a part of an air spring in longitudinal section and

1b and 2 B respectively the detail view X.

In the two figures of the drawing are the same parts always with the provided the same reference numerals.

1 and 2 show an air spring 1 for commercial vehicles.

The air spring 1 has a rolling piston 2 made of plastic and a rolling bellows 3 made of elastomeric material. The rolling bellows 3 has on his, the rolling piston 2 facing end a mounting bead 4 with a steel bead core 5 , The fastening bead 4 lies with its conical sealing surface 6 at a conical seat 7 of the rolling piston 2 and with its bottom 8th on the shoulder 9 of the rolling piston 2 sealingly.

According to the invention is on the shoulder 9 between cone seat 7 and the rolling edge 10 of the rolling piston 2 at least one circumferential sealing rib 11 is arranged.

2 shows opposite 1 a sealing rib 11 , which continues in the outer shoulder area, so close to the rolling edge 10 is arranged, whereby quasi a softer Rolgbalgwandabschnitt over the sealing rib 11 lies.

Incidentally, is in both embodiments a retaining lug to achieve the tightness is not required.

1

air spring

2

roll-off

3

bellows

4

fixing bead

5

bead

6

sealing surface

7

conical seat

8th

bottom

9

shoulder

10

roll-off edge

11

sealing rib

Claims (3)

Air spring ( 1 ) for commercial vehicles with a rolling piston ( 2 ) made of plastic and a rolling bellows ( 3 ) made of elastomeric material, wherein the rolling bellows ( 3 ) on his, the rolling piston ( 2 ) facing end a Befestigungswulst ( 4 ) with a bead core ( 5 ), which (4) with its conical sealing surface ( 6 ) on a conical seat ( 7 ) of the rolling piston ( 2 ) and with its underside ( 8th ) on a shoulder ( 9 ) of the rolling piston ( 2 ) sealingly, characterized in that on the shoulder ( 9 ) between conical seat ( 7 ) and the rolling edge ( 10 ) of the rolling piston ( 2 ) at least one circumferential sealing rib ( 11 ) is arranged. Air spring according to claim 1, characterized in that the sealing rib ( 11 ) on the shoulder ( 9 ) of the rolling piston ( 2 ) is injected. Air spring according to claim 1 or 2, characterized in that the sealing rib ( 11 ) is formed in cross-section V-, semi-oval, or semicircular.