COMPENSATING COUPLING

Abstract

A compensating coupling comprises two outer coupling parts, namely an input-side coupling part and an output-side coupling part, both of which are to be connected to rotatable elements, more particularly shafts, and a center coupling part, which can be moved to a limited extent relative to the outer coupling parts. The center coupling part is composed of: a tube piece in the form of a damping element; and two tube end pieces, which are fastened to the tube piece and which are each designed to be fitted onto one of the outer coupling parts in a centered manner by ball head centering.

Claims

1. A compensating coupling for compensating for a radial offset between two rotatable elements, the coupling comprising: two outer coupling parts configured for connection to the rotatable elements, including an input-side coupling part and an output-side coupling part; a center coupling part that is movable to a limited extent relative to the outer coupling parts; the center coupling part comprises a tube piece formed as a damping element and two tube end pieces fastened to the tube piece; and the two tube end pieces are each configured to be fitted onto a respective one of the outer coupling parts centered by ball head centering.

2. The compensating coupling according to claim 1, wherein at least one respective connection between the tube piece and a respective one of the tube end pieces comprises an overload coupling.

3. The compensating coupling according to claim 2, wherein both said connections between the tube piece and the respective tube end pieces comprise said overload couplings, and a load capacity of said connections is determined by an adhesive introduced between the tube piece and the tube end pieces.

4. The compensating coupling according to claim 1, wherein the tube piece comprises a fiber-reinforced plastic.

5. The compensating coupling according to claim 1, wherein the center coupling part is centered relative to the outer coupling parts by a respective ball head.

6. The compensating coupling according to claim 5, wherein the ball heads are components of the respective outer coupling parts.

7. The compensating coupling according to claim 5, wherein the ball heads are components of the tube end pieces.

8. The compensating coupling according to claim 5, further comprising a torque-transmitting connection between the ball head and the coupling part coupled thereto provided by a pin fixed in the ball head and a corresponding groove in said coupling part.

9. The compensating coupling according to claim 5, further comprising a torque-transmitting connection between the ball head and the coupling part coupled thereto formed via toothing of the ball head and of said coupling part.

10. The compensating coupling according to claim 5, wherein the ball head is followed by an extension section which, via interposition of at least one elastic ring, rests on an inner peripheral surface of one of the coupling parts.

11. A compensating coupling for compensating for a radial offset between two rotatable elements, the coupling comprising: two outer coupling parts configured for connection to the rotatable elements, including an input-side coupling and an output-side coupling part; a center coupling part that is movable relative to the outer coupling parts; the center coupling part comprises a tube piece formed as a damping element and first and second tube end pieces fastened to respective first and second ends of the tube piece; and the first and second tube end pieces are engaged on, respectively, the input-side coupling part and the output-side coupling part, centered by respective ball heads.

12. The compensating coupling according to claim 11, wherein at least respective connection between the tube piece and a respective one of the tube end pieces comprises an overload coupling.

13. The compensating coupling according to claim 12, wherein both said connections between the tube piece and the respective tube end pieces comprise said overload couplings, and a load capacity of said connections is determined by an adhesive located between the tube piece and the tube end pieces.

14. The compensating coupling according to claim 11, wherein the tube piece comprises a fiber-reinforced plastic.

15. The compensating coupling according to claim 11, wherein the ball heads are components of the respective outer coupling parts.

16. The compensating coupling according to claim 11, the ball heads are components of the tube end pieces.

17. The compensating coupling according to claim 11, further comprising a torque-transmitting connection between at least one of the ball heads and the coupling part coupled thereto provided by a pin fixed in the ball head and a corresponding groove in said coupling part.

18. The compensating coupling according to claim 11, further comprising a torque-transmitting connection between the ball head and the coupling coupled thereto formed via toothing of the ball head and corresponding toothing of said coupling part.

19. The compensating coupling according to claim 11, wherein art least one of the ball heads is followed by an extension section which, via interposition of at least one elastic ring, rests on an inner peripheral surface of one of the coupling parts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Two exemplary embodiments of the invention are explained in more detail below with reference to a drawing. In the drawing:

[0025] FIG. 1 shows a first exemplary embodiment of a compensating coupling, and

[0026] FIG. 2 shows a second exemplary embodiment of a compensating coupling.

DETAILED DESCRIPTION

[0027] Unless otherwise stated, the following explanations relate to both exemplary embodiments. Corresponding or basically identical parts are marked with the same reference symbols in all figures.

[0028] A compensating coupling, identified as a whole by the reference numeral 1, is intended for use in a test rig for spindle bearings. It is a high-speed application in which the compensating coupling 1 is operated under critical conditions. Spindle bearings with a speed index of up to 4,000,000 mmrpm are tested with the help of the compensating coupling 1. The compensating coupling 1 is thus part of a multi-shaft system operated at high speed.

[0029] The compensating coupling 1 comprises two outer coupling parts 2, 3, namely an input-side coupling part 2 and a driven-side coupling part 3, as well as a center coupling part 4 connecting the outer coupling parts 2, 3, which is designed as an intermediate coupling shaft. Overall, the compensating coupling 1 is able to compensate for both a lateral and an axial offset between the outer coupling parts 2, 3. The outer coupling parts 2, 3 are to be connected to shafts or other rotating elements. Alternatively, the coupling parts 2, 3 can be designed as integral components of such elements, that is to say of a driving element or an element on the output side.

[0030] In the exemplary embodiments, the input-side coupling part 2 has a flange 5 which is to be fastened to a driving element. Furthermore, a shaft 8 can be seen on the input-side coupling part 2, which can be used to center the input-side coupling part 2 on the driving element. As far as the coupling part 3 on the output side is concerned, a connection contour 6 can be seen in FIG. 2, which can be used for connection to a shaft on the output side. In the exemplary embodiment according to FIG. 1, the coupling part 3 on the output side is only partially shown.

[0031] The intermediate coupling shaft 4, which positively connects the outer coupling parts 2, 3 to one another in a manner that will be explained in more detail below, has a tube piece 7 in both exemplary embodiments, which acts as a damping element of the compensating coupling 1. The tube piece 7 is designed as a CFRP tube, which is wound with ultra-high modulus carbon fibers. In addition to its mechanical damping function, the tube piece 7 also represents an element for thermal decoupling and electrical insulation. In the arrangements according to FIGS. 1 and 2, the central axis of the tube piece 7, designated MA, and thus of the entire center coupling part 4, coincides with the central axes of the outer coupling parts 2, 3. The diameter of the center coupling part 4 denoted by D.sub.M is identical to the diameter of the tube piece 7. L.sub.M denotes the total length of the center coupling part 4.

[0032] In addition to the tube piece 7, two tube end pieces 9, 10, which are metal parts, are to be allocated to the center coupling part 4. An insert piece 11 is formed by each tube end piece 9, 10 and is held in the tube piece 7. The insert pieces 11 each have a first annular connecting section 12 and a second annular connecting section 13 spaced parallel therefrom. An intermediate section 14 with a comparatively small diameter is formed between the annular connecting sections 12, 13. The annular space between the intermediate section 14 and the inner peripheral surface of the tube piece 7 is filled with an adhesive 15, through which an overload coupling 17, 18 is formed. A front contact section 16 of the insert piece 11 borders on the two ends of the tube piece 7.

[0033] The center coupling part 4 is in each case centered relative to the outer coupling parts 2, 3 with the aid of a ball head 19, which is also generally referred to as a spherical section, so that there is a double ball head centering. Viewed in the longitudinal direction of the central axis MA, the spherical section 19 is adjoined on the one hand by a neck 20 and on the other hand by an extension section 21.

[0034] In the embodiment according to FIG. 1, the ball heads 19 are parts of the outer coupling parts 2, 3. A pin 23, which acts as a torque-transmitting element, is inserted through a bore 22, which runs through the center of the ball head 19 and intersects the central axis MA at right angles. The pin 23 engages in a longitudinal groove 24 which is located in the tube end piece 9,10. As is known from Oldham couplings, the pins 23 of the two outer coupling parts 2, 3 are rotated by 90° relative to one another. However, in contrast to conventional Oldham couplings, the center coupling part 4 cannot be displaced in relation to the outer coupling parts 2, 3, but can only be slightly tilted.

[0035] The centering of the center coupling part 4 relative to the outer coupling parts 2, 3 with the aid of two spherical heads 19 is also provided in the exemplary embodiment according to FIG. 2. In this case, the ball heads 19 have external toothing 31 which each engage in an internal toothing 32 in a form-fitting manner, enabling the transmission of a torque. The internal toothing 32 is formed in bores 29, 30 of the outer coupling parts 2, 3, while the ball heads 19 are formed as integral components of the tube end pieces 9, 10 on the insert pieces 11.

[0036] In both exemplary embodiments, there are two annular grooves 25, 26 in the extension section 21, in each of which an O-ring 27, 28 is inserted. The O-rings 27, 28, i.e. damping rings, represent a means of pre-centering when assembling the compensating coupling 1. In addition, the O-rings 27, 28 act as damping elements that are effective in the axial direction during operation of the compensating coupling 1.

[0037] The compensating coupling 1 is assembled by simply plugging the coupling parts 2, 3, 4 together. In a similar manner, the equalizing coupling 1 can be dismantled by pulling the coupling parts 2, 3, 4 apart, wherein access to the equalizing coupling 1 from one side, i.e. either from the input-side coupling part 2 or from the driven-side coupling part 3, is sufficient.

LIST OF REFERENCE SYMBOLS

[0038] 1 Compensating coupling [0039] 2 Outer coupling part, input-side [0040] 3 Outer coupling part, output-side [0041] 4 Center coupling part, intermediate coupling shaft [0042] 5 Flange [0043] 6 Connection contour [0044] 7 Tube piece, damping element [0045] 8 Shaft on the input-side coupling part [0046] 9 Tube end piece, input-side bushing [0047] 10 Tube end piece, output-side bushing [0048] 11 Insert piece [0049] 12 First annular connecting section [0050] 13 Second annular connecting section [0051] 14 Intermediate section [0052] 15 Adhesive [0053] 16 Front-side attachment section [0054] 17 Overload coupling [0055] 18 Overload coupling [0056] 19 Spherical section, ball head [0057] 20 Neck [0058] 21 Extension section [0059] 22 Bore [0060] 23 Pin [0061] 24 Groove, longitudinal groove [0062] 25 Annular groove [0063] 26 Annular groove [0064] 27 O-ring [0065] 28 O-ring [0066] 29 Bore [0067] 30 Bore [0068] 31 External toothing [0069] 32 Internal toothing [0070] D.sub.M Diameter of the center coupling part [0071] L.sub.M Length of the center coupling part [0072] L.sub.R Length of tube piece [0073] MA central axis