GB2117089A - Toothed coupling - Google Patents

Abstract

A coupling has an inner member 16 with two sets of external teeth 18 each of which engages in a set of internal teeth 22 of outer members 20. Formed axially beside each pair of meshing teeth in the associated outer member is an annular groove 26 which opens inwards and in which a two-part oil-retaining ring 28 is held. The oil-retaining ring consists of two ring portions 30, 34 each of which has an open sector (32 or 36) of less than 180 DEG and the ring portions lie side by side in the groove in such a manner that the open sectors are situated diametrically opposite one another. Each of the oil-retaining rings thus formed can easily be manufactured and installed and encloses an annular space in which a lubricant 48 is held back. Relative rotation of the ring portions is prevented by one or two projections (40) or 38. <IMAGE>

Description

SPECIFICATION Toothed coupling The invention relates to a toothed coupling having at least one inner coupling member provided with external teeth, at least one outer coupling member provided with internal teeth meshing with the external teeth and an oilretaining ring arranged to hold lubricant in the region of the teeth.

Toothed couplings are commonly used to connect together and transmit torque between two shaft systems which are mounted independently of one another, as a result of which relative radial and/or axial shaft displacements may occur in operation. Because of the misalignment of the axes of the shafts which can be expected to occur in operation, there will be relative movements between the meshing teeth of the coupling, on account of which the teeth have to be lubricated so that wear and resistance to movements within the coupling are kept low. In the case of high-speed couplings, it is usual to lubricate the teeth with lubricant injected continuously in operation.In order that the lubricant will not be thrown off by the centrifugal forces arising in operation, without having lubricated the teeth adequately, the regions surrounded by one coupling member and in which the meshing teeth are disposed, are enclosed in the axial direction by an oil-retaining ring.

In a known coupling of the kind referred to above, hitherto manufactured by the applicants, the oil-retaining ring is composed of two semicircular ring portions of U-shaped cross-section which are inserted axially in an annular seat in an outer coupling member with their ends lying against one another. The oil-retaining ring thus mounted is secured against axial displacement by a spring washer of round wire which is engaged in an annular groove axially beside the ring.

It is the object of the invention to provide a toothed coupling in which the oil-retaining ring may be more simply manufactured and mounted.

According to one aspect of the invention, there is provided a toothed coupling with inner and outer coupling members having internal and external teeth respectively which mesh to interengage the members, at a position offset from said teeth an oil retaining ring being provided to retain lubricant in the region of the teeth, said ring comprising two ring portions which each have a sector of less than 1 800 left open, each ring portion overlapping the open sector of the other ring portion and regions of said other ring portion at both ends of said open sector.

More particularly, the invention may provide a toothed coupling having at least one inner member which comprises external teeth, at least one outer member which comprises internal teeth meshing with the external teeth and an annular seat axially beside said internal teeth for an oilretaining ring which is composed of two ring portions and is secrued in the annular seat to hold lubricant in the region of the teeth, the annular seat comprising an annular groove which is substantially U-shaped in cross-section and the two ring portions each having an open sector of substantially less than 1 800, said portions being engaged axially side by side in the annular groove and being located in relation to one another in such a manner that each ring portion overlaps the open sector of the other ring portion and regions of the other ring portion adjacent thereto at both ends.

The two ring portions which together form the oil-retaining ring may each resemble an ordinary commercial split ring of spring steel known by the name of a Seeger ring and may be inserted in the manner in which such a ring is inserted in an annular groove, but the ring portions are arranged side by side as a pair and oriented in relation to one another in such a manner that together they form a peripherally continuous oil-retaining ring.

Conveniently each of the ring portions comprises a hole at its ends for an assembly tool, for example for a conventional form of pincers provided at its ends with parallel pins, such as are used for the mounting of Seeger rings.

The sector of each ring portion that is left open preferably extends over an angle of 30 to 50 .

In a preferred form of the invention, the two ring portions comprise means which limits or prevents a relative rotation of the two portions.

Such means may appropriately be formed from the open sector of one of the two ring portions and at least one projection on the other ring portion engaging in this sector. Said one ring portion is then preferably plane.

The open sectors of the two ring portions are preferably disposed diametrically opposite one another.

By way of example an embodiment of the invention is described below in more detail and with reference to the accompanying diagrammatic drawing, in which: Figure 1 shows in axial section a toothed coupling according to the invention.

Figure 2 shows an oil-retaining ring of the coupling in an oblique view and Figure 3 shows a modified oil-retaining ring, likewise in an oblique view.

The toothed coupling illustrated connects two shafts 12 and 14 to one another and has a sleeveshaped inner coupling member 1 6 which is disposed between these shafts for limited axial displacement and on each of the two ends of which external teeth 18 are formed. Secured to each of the two shafts 12 and 14 is a hub-like outer coupling member 20 on which internal teeth 22 are formed. The sets of internal teeth 22 are each in constant engagement with a respective one of the sets of external teeth 1 8 of the inner coupling member 1 6.

Each of the two outer coupling members 20 has, at its end remote from the associated shaft 12 or 14, an annular seat 24 with a groove 26 of U-shaped crosss-section which opens radially inwards. Mounted in each of the grooves 26 is a two-part oil-retaining ring 28, the internal diameter of which is smaller than the tooth root diameter of the adjacent external teeth 1 8.

Each of the two oil-retaining rings 28 comprises a first ring portion 30 with an open sector 32 and a second ring portion 34 with an open sector 36. The open sectors 32 and 36 lie diametrically opposite one another and each extends over an angle of about 400. The two ring portions 30 and 34 are made of spring steel with a narrow rectangular cross-section. The first ring portion 30 is plane; the second ring portion 34, on the other hand, as shown in Figures 1 and 2, has two projections 38 in the form of stamped studs with parallel axes, which engage in the open sector 32 of the first ring portion 30 and so prevent the ring portions 30 and 34, which are received in the associated groove 26 almost without clearance, from rotating in relation to one another.

In the modified ring shown in Figure 3, the second ring portion 34 has, instead of the two projections 38 illustrated in Figures 1 and 2, a single projection 40 which is defined by offsetting of this second ring portion 34.

In both the examples of ring illustrated, the two portions 30 and 34 have at their ends adjacent the open sector a pair of holes 42 with parallel exes.

Disposed in the lower region of the coupling are two nozzles 44 from each of which, in operation, a jet of lubricant 46 is directed into the space between each of the oil retaining rings 28 and the adjacent shaft 12 or 14. As a result, the space is kept filled with a lubricant 48 to a height which is delimited by the internal diameter of the oilretaining ring 28 in question, which lubircant constantly covers the meshing teeth 1 8 and 22.

During the assembly of the coupling, two pairs of ring portions 30 and 34 are passed over one of the two sets of external teeth 1 8 onto the inner member 16; the ring portions 30 and 34 are sufficiently resilient to be bent so far, without permanent deformation, that this positioning is easily possible. Then the inner member 1 6 is pushed axially into the two outer coupling portions 20 and these are bolted to the associated shaft 12 or 14. Then, of the two ring portions 30 and 34 which together provide an oil-retaining ring 28, first the first ring portion 30 is gripped at its two holes 42 by Seeger-ring pincers or a like tool to be contracted radially, inserted in the associated groove 26, and released in this so that it expands and locks in the groove. The associated second ring portion 34 is then engaged in a corresponding manner in the same groove 26 and in correct angular alignment to the first portion. The same thing is effected in succession with the two-ring portions 30 and 34 of the second oil-retaining ring 28.

If the jaw clutch has to be dismantled, the two oil-retaining rings 28 are dismounted in that first the second ring portion 34 in each case is gripped at its two holes 42 by the pincers tool and contracted, which is easily possible because the associated first ring portion 30 does not have any projection which would hinder such a contraction.

As soon as the second ring portion 34 has been removed from the groove 26, the first ring portion 30 can also be removed in a corresponding manner.

Claims (9)

1. A toothed coupling with inner and outer coupling members having internal and external teeth respectively which mesh to interengage the members, at a position offset from said teeth an oil retaining ring being provided to retain lubricant in the region of the teeth, said ring comprising two ring portions which each have a sector of less than 1800 left open, each ring portion overlapping the open sector of the other ring portion and regions of said other ring portion at both ends of said open sector.

2. A toothed coupling having at least one inner member which comprises external teeth, at least one outer member which comprises internal teeth meshing with the external teeth and an annular seat axially beside said internal teeth for an oilretaining ring which is composed of two ring portions and is secured in the annular seat to hold lubricant in the region of the teeth, the annular seat comprising an annular groove which is substantially U-shaped in cross-section and the two ring portions each having an open sector of substantially less than 1 800, said portions being engaged axially side by side in the annular groove and being located in relation to one another in such a manner that each ring portion overlaps the open sector of the other ring portion and regions of the other ring portion adjacent thereto at both ends.

3. A coupling as claimed in claim 1 or claim 2, wherein the ring portions comprise holes at their ends for an assembly tool.

4. A coupling as claimed in any one of claim 1 to 3 wherein the open sector of each individual ring portion extends over an angular region of 300 to 500.

5. A coupling as claimed in any one of the claims 1 to 4, the two ring portions comprise means which limits or prevents relative rotation between the portions.

6. A coupling as claimed in claim 5, wherein said means is provided from the open sector of one of the two ring portions and at least one projection on the other ring portion engaging in this sector.

7. A coupling as claimed in claim 6, wherein said one ring portion is plane.

8. A coupling as claimed in claim 6 or claim 7 wherein the open sectors of the two ring portions are disposed diametrically opposite one another.

9. A toothed coupling constructed and arranged for use substantially as described in the accompanying drawing.