DE102012212647A1 - Dry running compressor - Google Patents

Abstract

The invention relates to a dry-running compressor for compressing gases, in particular air, with at least one piston 1, which is movable in a cylinder by a drive and has a sealing collar 2 for sealing against the cylinder. According to the invention, the sealing collar 2 is provided substantially annularly and fixed by means of a ductile clamping ring 3 on an outer side 4 of the piston 1.

Description

The invention relates to a dry-running compressor for compressing gases, in particular air, with at least one piston, which is movable in a cylinder by a drive and having a sealing collar for sealing against the cylinder.

Pistons in dry running compressors for the air supply, eg. B. in air spring systems, are often equipped with sealing sleeves made of special PTFE material with L-shaped cross-section to seal the piston for the air compression in the cylinder. In this case, the elastic sealing sleeve is pressed by the air pressure from the inside against the cylinder wall and seals during the cylinder stroke by the sealing sleeve slides along the cylinder wall.

To attach the sealing sleeve this is often placed on a shoulder on the piston and fixed by a further plate-shaped or annular member on the piston and clamped, such as from the document DE 10 2008 031 848 A1 is known. In this case, the lower leg of the sealing sleeve must be clamped so strong that this compound remains airtight over all operating conditions, which is often difficult to achieve. The plate or annular components also limit the structural design of the piston.

It is therefore an object of the invention to provide a dry running compressor, which allows a simple, space-saving, easy to install and elastic over all operating conditions attachment of the sealing sleeve.

This object is achieved by a dry-running compressor according to claim 1 of the invention.

The sealing collar of the dry running compressor according to the invention is provided substantially annular and fixed by means of a ductile clamping ring on an outer side of the piston.

The clamping ring is pushed over the pushed onto the piston sealing collar and plastically deformed from the outside to the extent that after the elastic re-deformation sufficient preload force between the piston and the sealing sleeve is present. By thus not limited structural design of the piston and the clamping ring and by the deformation during clamping, the biasing force can be adjusted according to the requirements.

A simple assembly of the clamping ring is achieved in that the clamping ring before the plastic deformation has an inner diameter which substantially corresponds to an outer diameter of the sealing collar.

According to an advantageous embodiment of the invention, the piston in the clamping region of the sealing sleeve on a circumferential groove, in which the sealing sleeve is at least partially formed during the plastic deformation of the clamping ring. This makes it possible to ensure a sufficient clearance of the clamping ring outer diameter to the cylinder wall after the plastic deformation.

In order to further improve the sealing behavior between the piston and the sealing collar and to prevent the sleeve material from flowing away, according to an advantageous development of the invention, a peripheral groove structure is provided in a groove bottom of the circumferential groove.

According to a further advantageous embodiment of the invention, the sealing collar extends on the outside of the piston with a portion beyond the clamping area in the direction of the drive. The additional portion of the sealing sleeve can be used as a piston guide band, which supports transverse forces of the piston, for example, in a straight guided piston. An additional piston guide band can be omitted. Furthermore, a smaller space is required.

The dry running compressor according to the invention is applicable to all areas in which small compressors are used (air spring systems, Reifenfüllkompressoren etc.).

Other features, advantages and applications of the invention will become apparent from the dependent claims and the following description of exemplary embodiments and with reference to the drawings. It shows highly schematized as well as on average:

1 a detail of a piston of a first embodiment according to the invention a dry running compressor and

2 a detail of a piston of a second embodiment according to the invention a dry running compressor.

1 shows a section of a piston 1 a first embodiment of a dry-running compressor for compressing gases, in particular air, which is used in all areas in which small compressors are used (air spring systems, Tire inflation compressors, etc.). The general structure and function of such a compressor are well known, so that in the following only the features essential to the invention will be described.

The compressor has at least one piston 1 on, which is movable in a cylinder, not shown, by a drive. For example, a working movement of the piston can be generated via a crank drive, which essentially consists of a crankshaft with a connecting rod. An electric motor usually drives a drive shaft, which is connected via a roller bearing with the crankshaft, wherein an eccentric bearing of the connecting rod converts the rotational movement of the crankshaft in the substantially translational movement.

To the piston 1 for the air compression seal against the cylinder, the piston points 1 a sealing collar 2 which is made of an elastically deformable material such as polytetrafluoroethylene.

To a simple, space-saving, easy to install and elastic over all operating conditions attachment of the sealing sleeve 2 to allow this is provided substantially annular and is made by means of a ductile clamping ring 3 on an outside 4 of the piston 1 attached.

For fastening the sealing collar 2 becomes the clamping ring 3 over the on the piston 1 deferred sealing sleeve 2 pushed and plastically deformed so far with known manufacturing processes from the outside, that after the elastic re-deformation sufficient preload force between the piston 1 and sealing cuff 2 is available.

It is advantageous if the clamping ring 3 before the plastic deformation has an inner diameter, which is substantially an outer diameter of the sealing sleeve 2 corresponds to the assembly of the clamping ring 3 to simplify.

This attachment allows adaptation of the biasing force to different requirements, since neither plate nor annular fasteners the structural design of the piston 1 restrict.

In particular 1 can be seen, the piston has 1 in the clamping area of the sealing collar 2 a circumferential groove 5 on, in which the sealing cuff 2 at least partially during the plastic deformation of the clamping ring 3 is formed. In the clamping or fastening area of the sealing collar 2 can thus ensure a sufficient clearance of Klemmringausßendurchmessers to the cylinder wall after the plastic deformation.

Outside the mounting area, the sealing collar is used 2 as a sealing lip 6 which the piston 1 seals for the air compression in a compression chamber, not shown.

To the sealing behavior between pistons 1 and sealing cuff 2 To further improve and prevent flow of the sleeve material, in the groove bottom of the circumferential groove 5 a not shown, circumferential groove structure may be provided.

If it is not a vibrating piston but a straight piston (eg double-acting pistons in 2-stage compressors), this is in addition to the sealing sleeve 2 a piston guide band is required, which lateral forces of the piston 1 can support. Such a piston guide band is known to be generally in a groove below the sealing sleeve 2 inserted. The assembly is carried out either by elastic expansion and snap into the groove or by using a slotted piston guide band, which is used for the assembly of the piston 1 must be fixed again in the cylinder.

To avoid these disadvantages, the sealing sleeve extends 2 of the second embodiment according to 2 on the outside 4 of the piston 1 beyond the clamping area towards the drive. The additional section 7 the sealing cuff 2 , which is characterized by the in 2 shown embodiment of the piston 1 to the piston 1 applies, can be used as a piston guide band, which transverse forces of the piston 1 for example, supported by a straight guided piston.

LIST OF REFERENCE NUMBERS

1

piston

2

sealing sleeve

3

clamping ring

4

outside

5

groove

6

sealing lip

7

section

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008031848 A1 [0003]

Claims (5)

Dry-running compressor for compressing gases, in particular air, with at least one piston ( 1 ), which is movable in a cylinder by a drive and a sealing collar ( 2 ) for sealing against the cylinder, characterized in that the sealing collar ( 2 ) provided substantially annular and by means of a ductile clamping ring ( 3 ) on an outside ( 4 ) of the piston ( 1 ) is attached. Dry-running compressor according to claim 1, characterized in that the clamping ring ( 3 ) has an inner diameter prior to the plastic deformation, which essentially corresponds to an outer diameter of the sealing collar ( 2 ) corresponds. Dry running compressor according to claim 2, characterized in that the piston ( 1 ) in the clamping region of the sealing collar ( 2 ) a circumferential groove ( 5 ) into which the sealing collar ( 2 ) at least partially during the plastic deformation of the clamping ring ( 3 ) is formed. Dry running compressor according to claim 3, characterized in that in a groove bottom of the circumferential groove ( 5 ) is provided a circumferential groove structure. Dry-running compressor according to one of the preceding claims, characterized in that the sealing collar ( 2 ) on the outside ( 4 ) of the piston ( 1 ) with a section ( 7 ) extends beyond the clamping area in the direction of the drive.

Images