GB1565172A - Resilient rotary coupling - Google Patents

Description

(54) RESILIENT ROTARY COUPLING (71) We, MASCHINENFABRIK STROMAG GMBH., a Joint Stock Company organized under the laws of the Federal Republic of Germany, of Postfach 20072009, Hansastrasse 120, 475 Unna, Federal Republic of Germany, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a rotary coupling with a resilient intermediate ring, which is provided with teeth at its inner and its outer circumference and is held by these teeth in corresponding toothings of the two halves of the coupling.

Couplings of this kind are known (DT-PS 373,687). These kinds of construction have the advantage that owing to the characteristics of elasticity of the intermediate ring soft transmission characteristics of the coupling and a very elastic behaviour are achieved.

especially when the thickness of the inserted intermediate ring decreases. Couplings of this kind comprise moreover the advantage that a relatively good compensation for non-alignment of the two shaft ends to be coupled with one another is provided, which is likewise due to the elasticity of the intermediate ring. Constructions of this kind however exhibit the disadvantage that, when a greater elasticity is to be realised and accordingly a greater difference in diameter between the inner and outer diameters of the intermediate ring is selected, the danger occurs that as a result of twisting, the inner teeth of the intermediate element spring out of their toothings. The transmittable rotarv moments are therefore limited in these kinds of construction.

Constructions of elastic couplings are also known (DT-AS 1,031,062), in which it has been attempted to avoid this disadvantage by the strengthening of the tooth region at the inner side of the intermediate ring. To this end, it is necessary that the elastic rubber body of the intermediate ring should be fastened directly onto the hub either mechanically or through vulcanisation, which is technically very disadvantageous as regards production and mounting. In another arrangement the soft rubber body has been fastened upon a hard rubber ring, into which rings of wire rope were vulcanised. This arrangement had indeed primarily only the purpose of absorbing the forces occurring during stressing of the elastic rubber intermediate ring, but in this case the inner hub was provided with four teeth, and a strengthening of the inner region in the region of the toothings was also provided.

These constructions comprise on the other hand the decided disadvantage that apart from technical manufacturing difficulties the whole region of the inner toothing of the elastic rubber member must consist of essentially harder material, so that the rotary elasticity of the whole intermediate ring must likewise be smaller because of the deficiencv of the elastic region of the inner teeth. That is also the case for other known constructions (DT-AS 1,078,822), where both the inner region of the toothing of the elastic intermediate ring and also the outer toothings consist of a crown of steel teeth which is vulcanised-on. In this case also the elastic region is essentially reduced for a similar constructional size, so that indeed higher rotary moments can be realised, which per se impairs the desirable rotary elastic characteristics of the coupling.

The object of the present invention is to construct a coupling of the kind initially mentioned above, with deformable resilient teeth incorporated also at the inner toothing. in such a manner that higher rotary moments can be transmitted without impairment of the rotary elastic characteristics.

The present invention provides a resilient rotary coupling comprising inner and outer coupling parts linked by a resilient intermediate ring which is provided at least at its inner circumference with teeth and is held by the latter in corresponding toothings of the inner part of the coupling, said resilient intermediate ring being provided with a circumferential reinforcing ring located in the region of the roots of the teeth at said inner circumference.

By means of this arrangement it is ensured that during the occurence of higher rotary moments the inner teeth cannot spring out of their toothings. Their deformability is however deliberately not influenced, so that the rotary elastic characteristics of the couplings are preserved. The invention therefore leads in a different direction from the known constructions. It deliberately does not strengthen the inner teeth or provide teeth of a different material, but only aims at preventing the inner teeth of the resilient ring from springing out of their corresponding toothing. The teeth arranged at the inner diameter of the elastic rubber ring can therefore also deform in the rotary direction. although a substantial deformation in the radial direction is prevented. This has the result that higher rotary moments can be realised with preservation of the resilient length and thereby the rotary elastic characteristics of the coupling.

Advantageously the reinforcing ring is vulcanised-in and is adapted in its breadth to the thickness of the intermediate ring in the region of the roots of the inner teeth. Bv this arrangement the inner toothing is held over its whole breadth. The reinforcing ring can suitably be provided with bores, so that an intimate connection of the elastic rubber material with the reinforcing ring is possible. In order that the rotary resilient characteristics should be influenced to the minimum. the reinforcing ring is constructed in the form of a thin metal ring of which the radial dimension is only small in comparison with that of the resilient intermediate ring.

This thin metal ring is suitably arranged as near as possible to the region of the roots of the teeth, but not so near that only the teeth lie on the inner side of the metal ring. It has turned out to be suitable when the reinforcing ring has a diameter which is about 5% larger than the diameter of the intermediate ring at the roots of its teeth.

The invention is illustrated bv wav of example in the accompanying drawings. in which Figure I is a view of a coupling constructed in accordance with the invention.

shown partly in section, and Figure 2 is a section through the coupling along the line II-II of Figure 1.

In Figures 1 and 7 are shown two coupling halves 1 and 2 of a rotary elastic coupling.

The outer coupling half 2 comprises a flange part 2a. which is connected with a shaft end in a manner not further illustrated, and a toothed ring 2b, which is screwed onto the flange part 2a by means of screws 3. The ring 2b is provided on its inner side with inwardly directed round toothed ribs 4. over which are slid the corresponding tooth spaces of an elastic intermediate ring 5 inserted between the coupling halves 1 and 2. The inner half 1 of the coupling essentially comprises a hub part which is provided with outwardly directed teeth 6, which in the illustrated example have a special form insofar as they are broader in the region of the head 6a than in the region of the root 6b.

Between these single teeth 6 engage the inwardlv directed teeth 7 of the elastic rubber member 5, which are correspondingly formed and likewise in the region of their tooth roots 7b are smaller than in the head region. In the region of the roots 7b of the teeth 7 there is vulcanised into the elastic rubber intermediate ring 5, a thin metal ring 8 which, as apparent from Figure 2, is as broad as the elastic rubber intermediate ring 5 in the region 7b of the tooth roots. The metal ring 8 moreover comprises bores 10 equally distributed around its circumference and respectively symmetrical to the central plane 9 shown in Figure 2, in the illustrated example there being 16 pairs distributed around the circumference. The arrangement of the bores 10 is thus so selected that a respective bore is arranged on a radius passing through each tooth 7 and on the median line bisecting the angle between two such radii.

The arrangement in accordance with the invention enables the elastic rubber intermediate ring to deform over its whole radial dimension upon the occurrence of a rotary moment between the coupling halves 1 and 2. i.e. from its inner diameter (which corresponds approximately to the diameter 6b of the tooth roots of the coupling half 1) measured outwardlv to the outer diameter.

The metal ring 8 vuicanised therein does not prevent the deformation of the region of the teeth 7 in the rotary direction during the occurrence of a rotary moment. It serves only to prevent a radial outward displacement of the teeth when higher rotary moments occur. For this purpose the metal ring 8 should be arranged as near as possible to the roots 7b of the teeth 7. but not so near that the intermediate region 11 (see Figures 1 and 2) of the elastic rubber material between the metal ring and the head 6a of the teeth 6 of the inner coupling member is too small. It has become apparent that the arrangement is suitably advantageous when the metal ring has a central diameter which is about 5% greater than the diameter of the elastic rubber intermediate ring 5 in the region of the roots 7b of its teeth.

As can be seen in Figure 2, the thickness of the elastic rubber member 5 increases towards its inner diameter. The arrangement is so selected that the thickness at the inner diameter is approximately double that at the outer diameter. Approximately the same surface pressure then occurs on the flanks of the teeth at the outer toothing and at the inner toothing. The novel rotary elastic shaft coupling is characterised by a very rotary elastic behaviour that however allows relatively high rotary moments to be realised.

It is not necessary that the elastic rubber intermediate ring should have the form of tooth which is described and illustrated in the exemplary embodiments. It is also possible to provide other forms of tooth which can be selected with a view to the desired properties of the coupling. In such a case a vulcanised-in reinforcing ring in the form of a metal ring or the like also prevents springing of the inner teeth out of the inner coupling ring during the occurrence of higher rotary moments.

The form of tooth shown in the exemplary embodiment exhibits however the additional advantage that the external form of the teeth itself serves to counteract the springing of the teeth out of the inner toothing.

WHAT WE CLAIM IS: 1. A resilient rotary coupling comprising inner and outer coupling parts linked by a resilient intermediate ring which is provided at least at its inner circumference with teeth and is held by the latter in corresponding toothings of the inner part of the coupling, said resilient intermediate ring being provided with a circumferential reinforcing ring located in the region of the roots of the teeth at said inner circumference.

2. A coupling according to Claim 1, wherein the said reinforcing ring is vulcanised into the resilient ring and corresponds in its breadth to the thickness of the intermediate ring in the region of the roots of said teeth.

3. A coupling according to Claim 1 or 2.

wherein the reinforcing ring is provided with bores.

4. A coupling according to any one of Claims 1 to 3, wherein the reinforcing ring is a thin metal ring.

5. A coupling according to any one of Claims 1 to 4, wherein the reinforcing ring has a diameter which is approximatelv 5% greater than the diameter of the intermediate ring at the roots of the said teeth.

6. A coupling according to any one of Claims 1 to 5, wherein the thickness of the resilient intermediate ring increases from the outer circumference to the inner circumference, the thickness at the inner circumference being approximately double that at its outer circumference.

7. A resilient rotary coupling substantially as described herein with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. region of the roots 7b of its teeth. As can be seen in Figure 2, the thickness of the elastic rubber member 5 increases towards its inner diameter. The arrangement is so selected that the thickness at the inner diameter is approximately double that at the outer diameter. Approximately the same surface pressure then occurs on the flanks of the teeth at the outer toothing and at the inner toothing. The novel rotary elastic shaft coupling is characterised by a very rotary elastic behaviour that however allows relatively high rotary moments to be realised. It is not necessary that the elastic rubber intermediate ring should have the form of tooth which is described and illustrated in the exemplary embodiments. It is also possible to provide other forms of tooth which can be selected with a view to the desired properties of the coupling. In such a case a vulcanised-in reinforcing ring in the form of a metal ring or the like also prevents springing of the inner teeth out of the inner coupling ring during the occurrence of higher rotary moments. The form of tooth shown in the exemplary embodiment exhibits however the additional advantage that the external form of the teeth itself serves to counteract the springing of the teeth out of the inner toothing. WHAT WE CLAIM IS:

1. A resilient rotary coupling comprising inner and outer coupling parts linked by a resilient intermediate ring which is provided at least at its inner circumference with teeth and is held by the latter in corresponding toothings of the inner part of the coupling, said resilient intermediate ring being provided with a circumferential reinforcing ring located in the region of the roots of the teeth at said inner circumference.

2. A coupling according to Claim 1, wherein the said reinforcing ring is vulcanised into the resilient ring and corresponds in its breadth to the thickness of the intermediate ring in the region of the roots of said teeth.

3. A coupling according to Claim 1 or 2.

wherein the reinforcing ring is provided with bores.

4. A coupling according to any one of Claims 1 to 3, wherein the reinforcing ring is a thin metal ring.

5. A coupling according to any one of Claims 1 to 4, wherein the reinforcing ring has a diameter which is approximatelv 5% greater than the diameter of the intermediate ring at the roots of the said teeth.

6. A coupling according to any one of Claims 1 to 5, wherein the thickness of the resilient intermediate ring increases from the outer circumference to the inner circumference, the thickness at the inner circumference being approximately double that at its outer circumference.

7. A resilient rotary coupling substantially as described herein with reference to the accompanying drawings.