EP0461494B1 - Eccentric drive for a rotating mass - Google Patents

Description

The invention relates to an eccentric drive for a rotating mass according to the preamble of claim 1.

Such turning masses are formed, for example, by the rotors of displacement machines working according to the spiral principle and known from the Motortechnische Zeitschrift, MTZ 46 (1985) 323-327. Such machines are characterized by an almost pulsation-free conveyance of a gaseous working medium, for example consisting of air or an air-fuel mixture, and can therefore also be used with advantage for charging purposes of internal combustion engines. During the operation of such a positive-displacement machine operating as a compressor or pump, a number of approximately crescent-shaped working spaces are enclosed along the displacement chamber between the spiral-shaped displacement body and the two peripheral walls of the displacement chamber, which work spaces move from the inlet through the displacement chamber to the outlet, their volume constantly reduced and the pressure of the working fluid can be increased accordingly.

For the drive of such a displacement machine, it is known (DE-OS 35 38 522) to provide two eccentric arrangements arranged at a distance from one another, which may consist, for example, of eccentric cranks, one of the two eccentric arrangements essentially as a drive arrangement and the other essentially as Guide arrangement is formed. To avoid impermissibly high loads caused by tolerance accumulation during production or by different thermal expansion stretch between the two points of attack on the rotating rotor, it is also known from the cited document to provide a bearing arrangement provided with an elastic bedding at at least one of the points of attack, preferably at the point of attack of the guide device. The elastic bedding is formed by a rubber-elastic outer ring surrounding the bearing. It has now been shown that the heat generated by bearing friction and the friction of the elastic bedding exceeds the permissible limits, especially at higher speeds. As a speed-dependent cause, the deflection of the drive shaft or main shaft caused by the inertial forces in relation to a minimal deflection of the guide shaft or auxiliary shaft must be mentioned in particular. The resulting deviations in the position of the two eccentric shafts relative to one another can lead to the destruction of the elastic bedding or even one of the bearings.

From FR-A-25 32 011 the use of a rigid sliding block is known as a guide element which can be displaced parallel to the compensating direction in a parallel guide. Here, however, there is no elasticity in the guide direction, which runs transversely to the starting direction.

The object of the present invention is to further develop an eccentric drive of the type known from DE-OS 35 38 522 and in particular to avoid the occurrence of stresses and the associated development of heat.

According to the invention the object is achieved by the characterizing features of patent claim 1. Thereafter, the receptacle for the guide element is essentially elongated in the direction of an imaginary connecting line between the points of attack (compensation direction). The guide element is less rigid in the direction mentioned than in the transverse direction (guide direction) for this purpose, so that the bearing ring can evade in the compensating direction under any pressure that may occur.

Advantageous developments of the invention result from the subclaims. The receptacle can be designed both as an elongated hole, an oval opening or as an opening with a side open in the compensating direction of the rotating mass. It is crucial that the opening is larger in the direction mentioned than in the guide direction.

The guide element and the bearing ring are advantageously adapted to the particular shape of the receptacle. The receptacle can have parallel surfaces that permit displacement. The elastic guide element can be non-circular on its outer circumference, corresponding to the shape of the receptacle, as well as circular. A non-circular guide element can be inserted on the one hand in a form-fitting manner and on the other hand with play in the longitudinal direction of the receptacle. An embodiment with an oval receptacle and a corresponding oval elastic guide element, which is arranged in a form-fitting manner in the receptacle, is particularly advantageous. The bearing ring seated inside the guide element is circular. This way. a greater material thickness of the guide element than in the circumferential direction in the compensating direction of the rotating mass. Accordingly, the possibility of yielding to a pressure of the bearing ring is greater in the compensating direction than in the guide direction. Bearing-destroying or heat-generating tensions are effectively avoided in this way.

In further developments of the inventive concept, fat pockets can be provided in the guide element and / or in the receptacle for storing a lubricant. This applies in particular to guide elements which can be moved in the receptacle.

Figur 1

eine Teilansicht des erfindungsgemäßen Exzenterantriebes im Schnitt mit einem speziellen Führungselement;

Figur 2

eine Teilansicht entsprechend Figur 1, jedoch mit einem anderen Führungselement und mit entsprechend angepaßter Kombination Lagerring-Aufnahme;

Figur 3

eine Teilansicht der Drehmasse (Verdränger) mit erfindungsgemäßer Ausbildung der Aufnahme;

Figuren 4, 5 und 8

Variationen der Aufnahme im Verdränger gemäß Figur 3;

Figuren 6 und 7

Verdränger mit Aufnahme ähnlich Figur 3, jedoch mit eingesetzten unterschiedlichen Führungselementen;

Figuren 9 und 10

ein spezielles Führungselement im Schnitt und in der Seitenansicht;

Figuren 11 und 12

ein weiteres spezielles Führungselement in der Draufsicht und im Schnitt;

Figuren 13 und 14

Verdränger mit Aufnahme ähnlich Figur 7, jedoch mit verschiebbarem Führungselement und eingearbeiteten Fettaschen;

Figur 15

Verdränger mit Aufnahme ähnlich Figur 6, jedoch mit besonders gestaltetem Führungselement und entsprechendem Lagerring;

Figur 16

eine Teilansicht des Verdrängers mit der Aufnahme und eingesetztem Führungselement im Schnitt.

To avoid stresses caused by waves not aligned in parallel, the receptacle in the area of its inner wall and / or the guide element in the area of its outer circumferential surface can be spherical.
Particularly advantageous embodiments of the invention are explained in more detail below with reference to drawings. Show it:

Figure 1

a partial view of the eccentric drive according to the invention in section with a special guide element;

Figure 2

a partial view corresponding to Figure 1, but with a different guide element and with a suitably adapted combination bearing ring holder;

Figure 3

a partial view of the rotating mass (displacer) with inventive design of the recording;

Figures 4, 5 and 8

Variations in the uptake in the displacer according to FIG. 3;

Figures 6 and 7

Displacer with receptacle similar to Figure 3, but with different guide elements used;

Figures 9 and 10

a special guide element in section and in side view;

Figures 11 and 12

another special guide element in plan view and in section;

Figures 13 and 14

Displacer with receptacle similar to Figure 7, but with a sliding guide element and incorporated fat pockets;

Figure 15

Displacer with receptacle similar to Figure 6, but with a specially designed guide element and corresponding bearing ring;

Figure 16

a partial view of the displacer with the recording and inserted guide element in section.

Figures 1 and 2 show the basic structure of a guide device 10 formed by an eccentric arrangement for a displacer 11 of a spiral loader. The latter is eccentrically rotatably arranged in a two-part housing 12, 13 and is guided by a guide shaft 14 with an eccentric pin 15. The guide shaft 14 is itself supported by a ball bearing 16 in the housing part 12. An imaginary connecting line from the guide shaft 14 to a drive shaft, not shown, and back defines a compensation direction.

At the top of the displacer 11, a receptacle 17 for the eccentric pin 15 is formed in the form of a bearing eye. To compensate for operational or tolerance-related tensions between the eccentric pin 15 and the receptacle 17, an elastic bed 20 (guide element) in the form of a profile ring is provided between the two in addition to a needle bearing 18 and a bearing ring 19. The needle bearing 18 is sealed off from the outer bearing ring 19 by an additional sleeve 21, so that the grease for the needle bearing 18 cannot emerge from the area of the sleeve 21.

The elastic bedding 20 essentially differs in FIGS. 1 and 2. According to FIG. 1, a profile ring with a flat cross section is provided, which is essentially enclosed by the cross sections of the bearing ring 19 and the receptacle 17. The receptacle 17 is secured against axial deflection by a locking ring 22 in the bearing ring 19.

In contrast, an elastic bedding 20 is provided in FIG. 2, which is wider and stronger in cross-section and which in turn axially secures the receptacle 17 by external circumferential beads 23, 24. In addition, in FIG. 2 the elastic bedding 20 with the bearing ring 19 is fixed connected, e.g. B. by vulcanization or gluing.

The opening of the receptacle 17 is not circular, but rather elongated or oval. The exact shape of the opening is described below with reference to the other figures.

FIG. 3 shows a simplified representation of the section of the displacer 11 in which the receptacle 17 is provided. This is in the form of an elongated opening, not a circular one. The longer diameter D₂ of the receptacle 17 extends approximately in the compensating direction. A displacer 11 corresponds to the rotating mass mentioned at the beginning of the description. The smaller diameter D 1 extends approximately in the circumferential direction of the displacer 11.

Figures 4, 5 and 8 show variations in the shape and position of the receptacle 17. According to Figure 4, the longer diameter is inclined with respect to the compensating direction. This is advantageous under certain load conditions in the spiral loader.

According to Figure 5, the receptacle 17 is open in the compensating direction on the outer circumference 25. This enables a particularly simple assembly of the elastic bedding 20 or the guide element. The guide element can slide along the side walls 26, 27 delimiting the receptacle 17 in order to compensate for dimensional or installation tolerances and tension caused by operation.

FIG. 8 shows a receptacle 17 with semicircularly curved walls 28, 29, which are connected to one another by straight side walls 30, 31. In contrast, the curved areas of the receptacle 17 in FIG. 3 are elliptically shaped.

FIGS. 6 and 7 show the displacer 11 with elastic bedding 20 inserted into the receptacle 17. In both figures, the receptacle 17 is elliptically elongated. The shape of the guide element representing the elastic bedding 20 is adapted accordingly and completely fills the receptacle 17. In this case, the circular bearing ring 19 is drawn in the guide element. There is now a certain flexibility in the arrangement of the bearing ring 19 in the receptacle 17. This is greater in the compensating direction (distance A₂) than in the guide direction (distance A₁). Evasion of the bearing ring 19 in the compensating direction is therefore easily possible, while the guide function for the eccentric pin 15 (not shown in FIG. 6) is retained in the guide direction. FIG. 7 shows a modification of this. Thereafter, the guide element is circular in shape both inside and outside. A movement of the guide element 20 in the compensating direction (arrow 32) is possible by displacement within the receptacle and / or by an elastic deformation of the material of the elastic bedding. Also advantageous is an almost circular design of the contours of the guide element and embedding in an elongated receptacle, but the receptacle is completely filled by the latter by deforming the material of the guide element.

The above-mentioned and the following embodiments can be applied both to configurations according to FIG. 1 and to configurations according to FIG. 2. For configurations according to FIG. 2, only the guide element - as mentioned above - has to be of larger dimensions and be formed with the circumferential beads 23, 24.

Figures 9 to 12 show different variants of the guide element. According to FIG. 9, the guide element consists of an essentially circular base body 33 which has partial beads 34, 35 on opposite regions of its circumference. Figure 10 shows a side view of Figure 9 (or Figure 9 shows a section through Figure 10 along the line IX-IX). Thereafter, three partial beads arranged one above the other are provided on each side. FIG. 11 also shows an almost circular base body 36. However, cross-sectional reinforcements 37, 38 are provided on opposite regions of the circumference, which are connected to the base body 36 to form axially extending spaces 39, 40. FIG. 12 shows a section along the line XII-XII in FIG. 11.

FIGS. 13 and 14 show receptacles 17 with guide elements 20 displaceable therein. To store a lubricant, either the walls of the receptacle 17 have fat pockets 41, 42 or the guide element 20 itself (fat pockets 43, 44). The fat pockets 41 to 44 are preferably not arranged in the compensating direction, but rather transversely thereto. Such fat pockets can also be provided in all other embodiments.

Figure 15 shows another special feature. Here, the bearing ring 19 is non-circular, so that there is a positive connection with respect to the guide element 20. This prevents twisting of the two parts against each other. This is of great importance in the proposed elongated shape of the receptacle 17. Another advantageous possibility is to firmly connect the bearing ring 19 to the guide element 20, for. B. by vulcanization or gluing. As shown in FIG. 15, the guide element 20 can completely fill the receptacle 17 or else have an annular shape or have an elliptical shape and nevertheless not completely fill the receptacle 17.

FIG. 16 shows a further variant, this time for a guide element similar to the embodiment according to FIG. 2. The peripheral surface 45 of the guide element 20 is offset from the beads 23, 24 towards the center point, so that a gap is formed between the receptacle 17 and the guide element 20. This serves to receive a lubricant, so that the guide element 20 is displaceable in the receptacle 17.

Claims (12)

1. Eccentric drive for a rotating mass (11) having a drive device which is formed by means of a first eccentric arrangement and which engages at least one point on the rotating mass (11) and having a guide device which is formed by means of a second eccentric arrangement (15) and which engages at least a further point arranged at a distance thereto, furthermore having a bearing arrangement with a flexible bedding (20) comprising a guide element held between a bearing ring (19) of the bearing arrangement and a receiving device (17) provided on the rotating mass (11), the said bearing arrangement being provided at at least one of the engagement points, characterised in that the receiving device (17) is of an elongated construction substantially in the direction of an imaginary connection line between the engagement points (compensating direction), so that the second eccentric arrangement (15) is mounted in this direction in the receiving device (17) in a more flexible manner than in the transverse direction thereto (guide direction).
2. Eccentric drive according to claim 1, characterised in that the receiving device (17) is formed as an opening which is enclosed on all sides and is in particular of an oval shape.
3. Eccentric drive according to claim 1, characterised in that the receiving device (17) is constructed as an elongated opening having a region which is additionally open in the compensating direction of the rotating mass (displacer 11).
4. Eccentric drive according to one of claims 1 to 3, characterised in that the receiving device (17) comprises a crowned inner wall (30, 31; 26, 27) and/or a guide element (20) comprises a crowned outer peripheral surface.
5. Eccentric drive according to one of claims 1 to 4, characterised in that the receiving device (17) comprises recesses (grease pockets 41 to 44) for the purpose of storing a lubricating medium.
6. Eccentric drive according to one of claims 1 to 5, characterised in that the guide element (20) is displaceably arranged within the receiving device (17).
7. Eccentric drive according to one of claims 1 to 6, characterised in that for the purpose of preventing rotational movements and/or displacing movements in the receiving device, the guide element (20) is non-circular, preferably oval in shape, at its outer periphery.
8. Eccentric drive according to one of claims 1 to 7, characterised in that the guide element (20) has recesses (grease pockets 41 to 44) in its outer peripheral surface for the purpose of storing a lubricating medium.
9. Eccentric drive according to one of claims 1 to 8, characterised in that the guide element (20) comprises circumferential swellings (23, 24; 34, 35) in regions extending from the receiving device (17) for the purpose of fixing it axially with respect to the receiving device (17) and/or to delimit a space for the purpose of storing a lubricating medium.
10. Eccentric drive according to one of claims 1 to 9, characterised in that the inside of the guide element (20) and the outer periphery of the bearing ring (19) corresponding thereto are non-circular, in particular having a surface which is at least flat in sections.
11. Eccentric drive according to one of claims 1 to 10, characterised in that the guide element (20) is fixedly connected to the bearing ring (19), in particular being moulded onto the bearing ring (19) or being adhered thereto.
12. Eccentric device according to one of claims 1 to 11, characterised in that the guide element (20) is received by the receiving device (17) with a certain amount of clearance in the compensating direction.

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