WO2006066831A1

WO2006066831A1 - Dry-running swash-plate compressor with an antifriction bearing-mounted swash-plate

Info

Publication number: WO2006066831A1
Application number: PCT/EP2005/013605
Authority: WO
Inventors: Dieter Spurny
Original assignee: Knorr-Bremse Systeme für Nutzfahrzeuge GmbH
Priority date: 2004-12-20
Filing date: 2005-12-16
Publication date: 2006-06-29
Also published as: DE102004061235A1; EP1831553B1; DE502005003880D1; EP1831553A1; ATE393313T1

Abstract

The invention relates to a dry-running swash-plate compressor, particularly for generating compressed air in goods-carrying vehicles, comprising a swash-plate (2), which is fastened to a drive shaft (1) and which, via a bearing arrangement (3) interacting with the outer radial edge area, converts the driving rotational motion into a reciprocating motion that displaces the at least one piston rod (4), which is mounted on the bearing arrangement (3) and which is mounted on a piston (5) running inside an associated cylinder (6), in order to generate the compressed air. The swash-plate (2) is fastened to the drive shaft (1) via at least one antifriction bearing, which absorbs axial and radial forces and which is mounted coaxial to the swash-plate (2) so that the swash-plate (2) can rotate about the drive shaft (1) along the longitudinal axis.

Description

Dry-running swash plate compressor with a roller bearing swashplate

The invention relates to a dry-running swash plate compressor, in particular for compressed air generation in commercial vehicles, with a swash plate attached to a drive shaft, which converts the driving rotary motion into an oscillating lifting movement via a cooperating with the outer radial edge bearing arrangement, the at least one attached to the bearing assembly piston rod in a assigned cylinder running piston for generating the compressed air forwards.

The field of application of such a swash plate compressor extends primarily to commercial vehicle technology, in commercial vehicles come compressors are used, which are usually driven directly over the engine of the commercial vehicle and supply compressed air for feeding the compressed air electrical system. In commercial vehicles, the compressed air thus generated is used for example for operating a compressed air brake system.

In a generally known manner, primarily oil-lubricated reciprocating compressors are used for the production of compressed air in commercial vehicles. The lubrication of these compressors usually takes place from the oil circuit of the engine. In this case, however, inevitably oil passes through the pistons of the compressor in the generated compressed air. Depending on the age and maintenance condition of the compressor, significant quantities of oil can enter the environment via the compressed air, namely via various vent openings of the compressed air system. Another problem of oil-lubricated reciprocating compressors in the commercial vehicle sector is that ever higher operating pressures demanded from the compressor, which is accompanied by quite high thermal stresses, which leads to coking of a part of the oil passed into the compressed air. This carbon deposits itself within the interior of the cylinder in the compressor and downstream compressed air devices and influences there very sustainably their life. EP 0 859 151 A2 discloses a compressor for generating compressed air in commercial vehicles, which solves this problem in that the compressor is designed here to run as dry as possible. The compressor is constructed in the manner of a swash plate compressor and has only a conventional oil-lubricated engine, which consists essentially of a arranged on a drive shaft swash plate with hemispheres in bearing cups, which form a bearing assembly for transmitting the rotational movement in an oscillating stroke. From the bearing assembly extend piston rods to various pistons, which generate by a reciprocating motion in associated cylinders in a conventional manner, the compressed air. Usually several pistons are arranged on a circumferential circle adjacent to each other in order to realize the highest possible delivery of the swash plate compressor.

The attachment of the swash plate to the drive shaft is usually via a hub-shaft connection or by shrinking the central bore having a swash plate on the drive shaft. In the first case, the connection is detachable for repair purposes. In the latter case, there is an insoluble compound. Always done in the prior art, however, a fixed attachment of the swash plate against the drive shaft.

A critical issue in the prior design of the swashplate compressor engine is the design of the bearing assembly cooperating with the outer radial edge region of the swashplate. Because of the relative movement of the swash plate against the hemispheres of the bearing assembly here is a particularly high friction stress, which has previously been reduced by lubricating measures to a tolerable level. In particular, as a result of the startup of the drive shaft caused by the standstill jerking movements is the

Bearing arrangement additionally heavily loaded. The bearing assembly is also exposed to heavy loads when the piston perform their working movements against a high back pressure.

It is therefore the object of the present invention to reduce the load on the bearing assembly of a swash plate type compressor of the above type. The object is achieved on the basis of a dry running swash plate compressor according to the preamble of claim 1 in conjunction with its characterizing features. The following dependent claims give advantageous developments of the invention.

The invention includes the technical teaching that the swash plate is secured via at least one axial and radial forces receiving rolling bearing on the drive shaft, which is arranged coaxially with the swash plate, so that the swash plate is rotatable about its longitudinal axis about the drive shaft.

The advantage of the solution according to the invention consists, in particular, in that a more favorable distribution of forces of the driving force towards the bearing arrangement is realized via the roller bearing. Jerk movements of the drive shaft are compensated by a corresponding pivoting of the relative position of the swash plate to the drive shaft. This results in less friction on the cooperating with the outer radial edge region of the swash plate bearing assembly, which ultimately leads to less heat. This is the prerequisite for the fact that the compressor according to the invention is no longer drivable only by the powerful vehicle engine, but also by a separate auxiliary engine or by a drive energy branched off from the drive train.

Preferably, the rolling bearing is designed in the manner of a deep groove ball bearing. The deep groove ball bearing can absorb both axial and radial forces and thus ensures a particularly compact design for the rolling bearing.

Alternatively, however, it is also possible to form the rolling bearing from a combination of a radial bearing with a thrust bearing. This separate storage proves to be considerably cheaper compared to a deep groove ball bearing. Furthermore, such a bearing combination is more robust, so that a longer life can be achieved. As an axial bearing for such a combined roller bearing, for example, an axial ball bearing is suitable. However, it is also possible that other suitable thrust bearings are used. As a radial bearing is primarily a needle roller bearing, since this can be combined to save space with a thrust bearing. According to a further measure improving the invention, the at least one roller bearing should be lubricated via a pressure oil supply extending through the drive shaft to the roller bearing. This requires that pass through the drive shaft corresponding oil channels. Alternatively, however, it is also possible for at least one rolling bearing to lubricate via spray oil, which exits, for example, from the point of entry of the drive shaft into the compressed-air-side guide bore in the housing. Furthermore, it is also conceivable that form at least one rolling bearing between the drive shaft and swash plate as a permanently lubricated roller bearing.

Further measures improving the invention will be described in more detail below together with the description of a preferred embodiment of the invention with reference to FIGS. It shows:

1 shows a longitudinal section through a dry-running swash plate compressor,

2 shows a longitudinal section as an enlarged detail in the region of the swash plates according to a first embodiment, and

3 shows a longitudinal section as an enlarged detail in the region of the swash plates according to a second embodiment.

The dry-running swash plate compressor illustrated in FIG. 1 has a drive shaft 1 on the part of the engine, which is set into rotary motion by a motor (not shown here). On the drive shaft 1 is a swash plate 2 via a - not visible here - fixed bearings. The swash plate 2 sets via a bearing assembly 3, the rotational movement of a drive shaft 1 in an oscillating

Lifting movement around. The lifting movement is attached to a on the bearing assembly 3 Transfer piston rod 4. In addition to the piston rod 4 further piston rods with associated bearing arrangements are available; The following description is thus to be understood as an example. The piston rod 4 forwards the reciprocating motion generated due to the rotation of the swash plate 2 to a piston 5 which is coaxially fixed to the end of the piston rod 4 opposite the bearing assembly 3. The piston 5 runs within an associated cylinder, in which the compressed air is generated due to the movement of the piston 5. A suction of air from the atmosphere takes place through the piston 5, which has a check valve assembly 7 for this purpose. The compressed air leaves the cylinder 6 via a further correspondingly designed check valve arrangement 8 on the cylinder piston 9, which is attached to the valve housing 10. Via a guide bore 11, the piston rod 4 is guided axially relative to the compressor housing 10.

According to Figure 2, the swash plate 2 is mounted on the manner of a deep groove ball bearing 12 rolling bearing, which is arranged coaxially with the swash plate 2 and ensures a so-called four-point storage. As a result, the swash plate 2 is rotatable about the drive shaft 1 along its longitudinal axis. The deep groove ball bearing 12 is lubricated via a through the drive shaft 1 to the deep groove ball bearing 12 extending pressure oil supply 15.

According to the Ausführungsforai shown schematically in Figure 3, the rolling bearing between the drive shaft 1 and swash plate 2 from a combination of a radial bearing 13 with a thrust bearing 14. The radial bearing 13 is here designed in the manner of a ball bearing, whereas the thrust bearing 14 formed in the manner of Axiahillenkugellagers is.

The invention is not limited to the two preferred embodiments described above. On the contrary, modifications are conceivable which are encompassed by the scope of protection of the following claims. Thus, it is also conceivable, for example, to carry out the rolling bearing of the swash plate on the drive shaft via other types of rolling bearings, as long as the axial and radial forces occurring at this point are thereby adequately intercepted. LIST OF REFERENCE NUMBERS

1 drive shaft

2 swash plate 3 bearing arrangement

4 piston rod

5 pistons

6 cylinders

7 Check valve device 8 Check valve device

9 cylinder head

10 housing

11 guide hole

12 Deep groove ball bearings 13 Radial bearings

14 thrust bearings

15 pressure oil supply

Claims

Accepted

1. A dry-running swash plate compressor, in particular for compressed air generation in commercial vehicles, with a drive shaft (1) fixed swash plate (2), which interacts via a cooperating with the outer radial edge region of the bearing assembly (3) the driving rotary motion in an oscillating stroke movement, the at least one the bearing assembly (3) attached piston rod (4) on in an associated cylinder (6) running piston (5) for generating the compressed air weiterleitet, characterized in that the swash plate (2) via at least one axial and radial forces receiving rolling bearing on the drive shaft (1) is fixed, which is arranged coaxially with the swash plate (2), so that the swash plate (2) along the longitudinal axis about the drive shaft (1) is rotatable.

2. Dry running swash plate compressor according to claim 1, characterized in that the rolling bearing in the manner of a deep groove ball bearing (12) is formed (Fig. 2).

3. Dry running swash plate compressor according to claim 1, characterized in that the rolling bearing consists of a combination of a radial bearing (13) with a thrust bearing (14) (Fig. 3).

4. Dry running swash plate compressor according to claim 3, characterized in that the radial bearing (13) is designed in the manner of a needle bearing.

5. Dry running swash plate compressor according to claim 3, characterized in that the axial bearing (14) is designed in the manner of an axial ball bearing.

6. Dry running swash plate compressor according to claim 1, characterized in that the at least one rolling bearing over a through the

Drive shaft (1) to the rolling bearing towards running pressure oil supply (15) is lubricated.

7. Dry running swash plate compressor according to claim 1, characterized in that the at least one rolling bearing is lubricated by spray oil, which emerges from Spritzölöffhungen in the region of the drive-side housing (10) in the direction of the swash plate (2).

8. Dry running swash plate compressor according to claim 1, characterized in that the at least one roller bearing is lubricated for life.