EP0270917B1 - Spring elastic eccenter bearing for a displacement machine - Google Patents

Description

The invention relates to an eccentrically and elastically designed mounting of a displacer executing a circular translational movement in an displacement machine around an eccentric.

DE-OS 28 31 179 discloses such a bearing. The drive shaft of the displacer is designed as a crankshaft, on the crank pin of which a sleeve is pushed which carries an elastic ring made of rubber or an elastomer with a central bore. This elastic ring sits in an adapted front recess of the displacer. Two anti-rotation devices are provided for the displacer, each having a crank mounted in a sleeve in the housing, the crank pin of which is connected to the displacer in the same way as the crank pin of the drive shaft.

A displacement machine designed as a rotary piston machine can e.g. see DE-OS 22 30 773. The displacer (piston) executes a circular (translational) movement around an eccentric. For this, eccentric shafts in a machining or built version have to be produced in a costly manner. When selecting certain operating pressures, e.g. Displacement machines designed as pumps repeatedly result in problems with the design and tolerance of the eccentric shafts of the displacement bearings. Displacers for pumps can be formed axially on one side or double-sided in such machines, so that there is in itself the possibility of supporting the displacers in a resilient manner both radially and axially. In this way, depending on the choice of the spring characteristics, the pressure ranges for such pumps can be set. Such pressure-limited positive displacement pumps partly have the characteristics of flow pumps without the disadvantages such as lack of self-priming ability, cavitation problems with throttled pipe cross sections and the like of turbomachines.

CH-PS 555 476 discloses a displacement machine with a curved displacer, which is rotatably mounted on an eccentric coupled to a rotatably mounted drive shaft and is guided through it to perform a circular movement in a correspondingly curved displacement chamber with an inlet and an outlet . The displacer can be deflected against the action of an elastic force from the contact position with the wall of the displacement chamber along lines of contact parallel to the axes of curvature. A metallic spring element, which acts as an energy store, is provided to generate the elastic force. The spring element can be formed by the displacer formed as a leaf spring bent about a bending axis parallel to the axis of the circular movement. The spring element can also be formed by an elastically deflectable wobble rod which; is articulated at one end to the displacer and is mounted between its ends in a ball joint whose center lies on the axis of rotation of the drive shaft.

With displacement machines of this type, there are considerable functional problems. The elastically deflectable wobble rod mentioned cannot be realized for reasons of sealing technology. Built eccentric shafts with metallic springs require additional guide elements for support and therefore also have additional cost disadvantages.

DE-OS 26 03 462 discloses a positive displacement machine for compressible media. Here, too, the displacer describes a circular translational movement around an eccentric track. In such designs, it is essential to provide an anti-rotation device for the displacer, since otherwise the displacer would immediately suffer mechanical damage if the rotation movement was slight even in addition to the circular movement. Eccentric shafts of costly construction or machined production are also used for these displacement machines, the displacer also being able to be axially sprung and additionally supported with an integrated anti-rotation device. A known anti-rotation lock comprises a plurality of balls, each loaded by compression springs, which execute a slight eccentric movement in correspondingly designed pans.

DE-OS 35 38 522 discloses an anti-rotation device with spring-elastic play compensation for the displacer of a displacement machine. The training is comparable to that of DE-OS 28 31 179.

The invention has for its object to construct the above-described storage of a displacer so that it can be manufactured more cost-effectively.

This object is achieved in that the displacer has a rotatably mounted in it, the eccentric bearing disc in which an eccentric to an outer bearing surface forming the bearing surface is arranged a recess for the rotationally fixed reception of a shaft, the space between the bearing shell and Recess with a rubber-elastic material, such as. B. rubber, is filled to produce a radial elasticity.

DE-OS 22 25 327 it is in a displacement machine designed as a vacuum pump with a circular translational movement around an eccentric displacer known to drive the displacer via three eccentrics acting on its circumference, each rotating in a ball bearing and each formed by an eccentrically fixed socket on the drive shaft. The eccentric bearings are not designed to be elastic, so that there is no generic embodiment in which the problems resulting from an elastic displacement bearing cannot arise.

GB-A-533 960 discloses, as a shock absorber for the suspension of vehicle parts, a disc which consists of an outer ring, an inner ring which is arranged eccentrically thereto and a rubber material which fills the space between the two rings. This shock absorber disc should be mounted so that the inner ring rests on the largest rubber cross-section in the direction of the compressive force acting on it. With e.g. The disk should be mounted so that the inner ring is offset by the eccentricity.

DE-A-25 18 150 discloses an eccentric shaft, preferably intended for radial and rotary piston machines, consisting of an essentially cylindrical shaft with an eccentric cooperating with the piston. The eccentric shaft consists of an outer ring body, a shaft penetrating the ring body and a connecting element connecting both parts. The connecting element can be designed as an injection molded part, which is produced by injection between the ring body and the shaft and is made of plastic, as a result of which a certain elasticity is introduced into the transmission of the eccentric shaft.

Since it is already possible to impart different spring characteristics to a plastic by means of electron beam crosslinking, it would be possible to form the bearing disk according to the invention in one piece. For a more conventional production, however, it is advantageous if the outer bearing jacket is a bearing ring, into which a bush forming the aforementioned recess is vulcanized. The bearing ring can preferably be the inner ring of a rolling bearing.

As an elastic material e.g. Find rubber. The operating temperatures for the choice of rubber material and the desired operating pressures for the Shore hardness (spring characteristic) of the rubber as well as for the cross sections of the eccentric bearings are decisive. A specific spring characteristic can be achieved by specifically arranged and designed cross-sectional weakenings (notches, beads and / or channels or the like) in the elastic material.

The bearing disc according to the invention is simple to manufacture, quick and easy to assemble, reliable in operation but economical in maintenance. Tests have shown that the elastic bearings according to the invention not only achieve the specified operating pressures perfectly, but that, in particular in multi-shaft machines, the tolerances of the individual machine parts are compensated properly.

For the torque transmission between shaft and elastic bearing all conceivable form-fitting and / or non-positive connection technologies such as thread, key / groove connection, pressing or the like can be used. to get voted.

A bearing which is not only elastic in the radial direction but also in the axial direction is characterized in accordance with the invention in that the bearing ring and / or the bushing covers or covers a portion of the end faces of the elastic material with a collar.

The object on which the invention is based can also be achieved in accordance with an alternative solution in connection with the features mentioned at the outset in that the displacer has a bearing disc which is rotatably mounted in it and forms the eccentric and in which a recess is formed eccentrically to an outer bearing surface which forms the bearing surface the inclusion of a pin or the like. is arranged, wherein the bearing disk consists of two cover disks sandwiching between them a layer of elastic material.

In this embodiment, the displacer is elastically supported in the axial direction. This embodiment can be used in particular as a reliable anti-rotation device, which can also be produced particularly inexpensively.

• Figur 1 eine Lagerscheibe in Draufsicht;
• Figur 2 einen Querschnitt der Lagerscheibe gemäß Figur 1;
• Figur 3 in einer abgewandelten Ausführungsform eine Lagerscheibe in einer Darstellung gemäß Figur 1;
• Figur 4 die Lagerscheibe gemäß Figur 3 im Querschnitt (obere Hälfte) sowie in Stirnansicht (untere Hälfte);
• Figur 5 eine abgewandelte Ausführungsform einer Lagerscheibe in einer Darstellung gemäß Figur 1;
• Figur 6 die andere Stirnseite der Lagerscheibe gemäß Figur 5;
• Figur 7 ein Querschnitt gemäß der Linie VII-VII in Figur 6;
• Figur 8 eine abgewandelte Ausführungsform einer Lagerscheibe in einer Darstellung gemäß Figur 5;
• Figur 9 einen Querschnitt durch die Lagerscheibe gemäß Figur 8;
• Figur 10 in Draufsicht und zum Teil im Schnitt gemäß der Linie B-B in Figur 11 eine Exzenterlagerung mit einer Verdrehsicherung für einen Verdränger und
• Figur 11 in vergrößertem Maßstab einen Schnitt gemäß der Linie A-A in Figur 10.

Some exemplary embodiments of the invention are shown in the drawing. Show it:

• Figure 1 shows a bearing washer in plan view;
• Figure 2 shows a cross section of the bearing washer according to Figure 1;
• Figure 3 in a modified embodiment, a bearing plate in a representation according to Figure 1;
• Figure 4 shows the bearing washer according to Figure 3 in cross section (upper half) and in front view (lower half);
• FIG. 5 shows a modified embodiment of a bearing disk in a representation according to FIG. 1;
• FIG. 6 the other end face of the bearing washer according to FIG. 5;
• 7 shows a cross section along the line VII-VII in Figure 6;
• Figure 8 shows a modified embodiment of a bearing plate in a Representation according to Figure 5;
• 9 shows a cross section through the bearing washer according to FIG. 8;
• Figure 10 in plan view and partly in section along the line BB in Figure 11, an eccentric bearing with an anti-rotation device for a displacer and
• FIG. 11 shows an enlarged section along the line AA in FIG. 10.

FIG. 1 shows a bearing disc 3, in which a recess 5 for receiving a shaft, not shown, is arranged eccentrically to the outer bearing jacket 4. The material 7 filling the space between the bearing jacket 4 and the recess 5 is designed to be rubber-elastic. The outer bearing jacket 4 is formed by a bearing ring 8, into which a bush 9 forming the said recess 5 is vulcanized.

Figures 3 and 4 show that the bearing ring 8 also be the inner ring of a roller bearing 10. In both exemplary embodiments according to FIGS. 1 to 4, the inner diameter of the bearing ring 4 is a multiple of that of the bushing 9.

In the two exemplary embodiments according to FIGS. 1 to 4, the bearing disk 3 has spring-elastic properties exclusively in the radial direction.

In order to obtain an eccentric bearing designed not only in the radial direction but also in the axial direction, according to FIGS. 5 to 7 both the bearing ring 8 and the bushing 9 can each have a portion of the end faces of the rubber-elastic material 7 with a collar 11 or 12 cover. The spring-elastic path in the radial direction is determined by the radial distance 15 between the collar 11 and the bushing 9 or by the radial distance 16 between the collar 12 and the bearing ring 8. In the exemplary embodiment, this radial spring travel is relatively short; Figure 7 shows that the resilient design is greater in the axial direction. This results from the axial distance between the aforementioned collars 11 and 12 and from the elasticity of the rubber-elastic material 7. The radial distances 15, 16 between the collar 11 and the bushing 9 or the collar 12 and the bearing ring 8 can be different from the rubber-elastic one Material 7 filled out or left out of this material.

The bearing disc 3 according to FIGS. 8 and 9 has spring-elastic properties only in the axial direction. Here, the bearing disk 3 consists of two cover disks 14, which sandwich a layer of rubber-elastic material 7 between them. As in the embodiments described above, a recess 5 for receiving a pin or the like is arranged eccentrically to the outer bearing jacket 4. FIG. 9 shows that the rubber-elastic material 7 is arched somewhat radially inwards between the two cover disks 14 both in the area of the bearing casing 4 and in the area of the recess 5.

Figures 10 and 11 show the possible uses for the bearing disks described above. FIG. 11 shows a cross section through a displacement machine and reveals a displacer 1 which carries out a translational movement about an eccentric a with respect to a displacement chamber or a displacement housing 2. Here, the displacer 1 is driven in a conventional manner via an eccentric shaft 6. According to the invention, a bearing disk 3 according to FIGS. 1 to 6 can be used for the eccentric bearing of the displacer. In addition, FIGS. 10 and 11 also show an anti-rotation device for the displacer 1. This anti-rotation device is formed by a bearing disk 3 according to FIGS. 8 and 9, that is to say a bearing disk which is designed to be spring-elastic only in the axial direction. A pin 13 engages in the recess 5 arranged eccentrically to the outer bearing jacket 4 by the dimension a.

Claims (7)

1. Eccentrically and resiliently constructed bearing of a displacer (1) performing a circular translational movement about an eccentric in a displacer machine, characterized in that the displacer (1) has mounted rotatably therein a bearing plate (3) which forms the eccentric and in which a cutout (5) is arranged eccentrically with respect to an outer bearing casing (4) forming the bearing surface, for non-rotatably receiving a shaft (6), the intermediate space between the bearing casing (4) and the cutout (5) being filled with a rubber-elastic material (7) such as caoutchouc to produce a radial resilience.

2. Bearing according to Claim 1, characterized in that the outer bearing casing (4) is a bearing ring (8) into which a lining (9) forming the said cutout (5) is vulcanized.

3. Bearing according to Claim 2, characterized in that the bearing ring (8) is the inner ring of a roller bearing (10).

4. Bearing according to Claim 2 or 3, characterized in that the internal diameter of the bearing ring (8) is a multiple of that of the lining (9).

5. Bearing according to one of the preceding claims, characterized in that, to achieve a particular spring characteristic in the rubber-elastic material (7), there are provided notches, beadings and/or channels or the like as cross- sectional weakening points.

6. Bearing according to one of Claims 2 to 5, characterized in that the hearing ring (8) and/or the lining (9) cover a part region of the end sides of the rubber-elastic material (7) by means of a collar (11, 12).

7. Bearing according to Claim 1, characterized by a twist-prevention means for the displacer (1), comprising a bearing plate (3) in which a cutout (5) is arranged eccentrically with respect to the outer bearing casing (4), for receiving a peg (13) or the like, the bearing plate (3) comprising two cover plates (14) which enclose between them in the manner of a sandwich a layer of rubber-elastic material (7).

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