GB1598897A

GB1598897A - Free-wheel coupling device

Info

Publication number: GB1598897A
Application number: GB20128/78A
Authority: GB
Original assignee: Nadella SA
Current assignee: Timken France SAS
Priority date: 1977-06-08
Filing date: 1978-05-17
Publication date: 1981-09-23
Also published as: IT7849727A0; ES470640A1; FR2393980B1; JPS6120737B2; IT1105120B; JPS545157A; FR2393980A1

Description

(54) FREE-WHEEL COUPLING DEVICE (71) We, NADELLA, a French Body Corporate, of 133-137 Boulevard National, 92505 Rueil-Malmaison, France, 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 present invention relates to a freewheel coupling device.

A known type of free-wheel coupling device comprises a cage for retention of a plurality of wedging elements intended to be interposed between an outer ring and an inner ring, one of which rings is equipped with a circular series of ramps, and elastic means, generally formed by a series of springs connected to cage sockets, to ensure the wedging of the elements for a given direction of relative rotation of the rings.

Known free-wheel coupling devices with reliable operation generally have a high cost that is mainly due to the complexity of the cage used and to the multiplicity of the elements forming the devices.

On the other hand, devices utilising a single member for the locking thrust of the assembly of wedging elements possess at least one of the following drawbacks:- they necessitate the use of special parts and especially special cages; they are of poor reliability as regards the elastic means for thrusting the wedging elements into the locking position; the elastic thrust means by reason of their form and arrangement necessitate the use of thrust washers in the axial direction of the cage with the consequence of an increase of the number of parts and of the assembly operations; and they are unsuitable for the transmission of axial thrusts.

The purpose of the present inven tion is thus to remedy the above-mentioned drawbacks by proposing a simple but reliable device formed mainly from standard bearing parts.

According to the present invention, a free wheel coupling device, of the type comprising a guide cage for a plurality of wedging elements disposed between a cylindrical track and a ring equipped with a series of ramps against which the wedging elements are thrust to lock the device, for a given direction of relative rotation between the track and the ring, by means of an elastic connection between the cage and the ring carrying the ramps, is characterised in that the elastic connection is formed by at least one radial projection on the cage which directly or indirectly elastically bears against a generally radial surface of the ramped ring.

The radial ring surface may be formed by a radial wall of an axial groove or shoulder in the ring.

According to a first embodiment of the invention, an elastic member is disposed between the or each radial cage projection and the associated radial ring surface.

The above and other features of the present invention are illustrated, by way of example, by the accompanying drawings, wherein:- Fig. 1 is, in radial section, a first embodiment of a free-wheel coupling device according to the invention, Fig. 2 is a section along the line 11-11 in Fig. 1, Fig. 3 is a detailed axial section illustrating the indirect elastic connection between a radial cage projection and a radial ring surface, Fig. 4 is a perspective view of the cage of the coupling; and Fig. 5 is a similar section to Fig. 3, but illustrating a direct elastic connection.

The free-wheel coupling device shown in Figs. 1 and 2, consists of a cage 1 having pockets 2 to retain and guide a plurality of cylindrical wedging elements 3, formed by rollers or needles, and disposed between a cylindrical inner track on an inner ring 5, provided with integral radial shoulders 6 for axial guidance of the elements 3 and possible transmission of axial thrusts through the intermediary of the radial faces 4 of these elements, and an outer ring 7 equipped with attached radial flanges 8, forming guide shoulders, made fast with the ring by a series of rivets 10, or by any other means such as bolts for example, the outer ring 7 having attached thereto or integral therewith a track having a circular series of wedging ramps 11.

The cage 1 is shown in more detail in Fig. 4, can be metallic or of synthetic material, and has a radial projection 13, that is preferably curved and, in the case of a metallic cage, formed by bending out of the cage a tab that, preferably, has a slight curvature towards the interior of the cage. Such a tab 13 may be ;;r shaped or of any other form that can be obtained by cutting and bending of cage material normally removed to form a pocket 2', which preferably will be without a wedging element, the projection or tab 13 being intended to come into elastic abutment, through the intermediary of an elastic member consti tuted by a spring 17 for example (Fig. 3), against the radial wall 18 of a generally axial groove 21 formed in the ring 7. The spring 17 being at least partially inserted in the groove 21.

Fig. 3 shows the form and manner of connection of the spring 17 which is generally "hat" shaped, the cage projection 13 bearing upon the central convex part 19 of the spring to ensure that the wedging elements 3 are thrust into the locking position.

As known, the device according to the invention is intended to ensure the driving, by a driving shaft made fast by any means with the inner ring 5, of a shaft or any other driven member made fast with the outer ring, for a given direction of rotation of the driving shaft.

In fact, the rotation in the anti-clockwise direction of the inner ring 5, by virtue of the cosperation of the cage 1 and the spring 17, ensures wedging of the elements 3 against the ramps 11 and consequent driving of the outer ring 7.

Rotation of the inner ring 5 in the opposite direction pushes the wedging elements back towards the bottoms 22 of the ramps where the elements can no longer effect transmission of movement to the outer ring.

In order to obtain better balancing of the device, the cage may have certain pockets empty, for example three pockets staggered by 120 , at least one of which has a tab 13 projecting radially therefrom.

Fig. 5 shows an alternative embodiment to that shown by Fig. 3, in which the cage 1 is made of a material possessing the necessary flexibility and resilience permitting the radial projection or tab 13 to fulfil the elastic function of the spring 17.

In fact, this figure shows a flexible tab 13 (drawn in dotted lines in Fig. 4) of generally curved or facetted form having one and preferably two arms 23 contacting the radial wall 18 of the groove 21 into which it is inserted. Such an arrangement provides direct elastic connection of the cage with the ring 7 ensuring that the wedging elements 3 are thrust into the locking position without the use of a separate spring.

It is also possible to provide a cage equipped with two or more radial projections 13 in regular or irregular distribution co-operating with respective radial ring surfaces either directly or via elastic members inserted into axial grooves possessing the same distribution in the ramped ring. In an extreme case, as many cage radial projections 13 and ring radial surfaces 18, with or without intermediary springs 17, can be provided as the cage comprises pockets. In this case, the pockets having radial projections 13 would also have to have wedging elements 3.

The radial surfaces can be formed by axial shoulders separating successive ramps in the ring 7.

In the above examples, the projection 13 has been described as being an integral part of the cage 1 which could be formed by any part of the latter such as a bar, an edge or even an extremity when an open cage is used.

The projection 13 could equally be formed by a separate piece attached, for example by welding, to the cage.

The rings are preferably machined or sintered but it is possible for at least one ring, and more particularly the one having a ramped track, to be obtained by a cold deformation process such as stamping for example.

The wedging elements could be balls instead of needles or rollers.

Finally, the devices described can be reversed by the use of an inner ring equipped with wedging ramps and at least one radial surface co-operating with a cage equipped with a radial projection inturned towards the axis of the device.

WHAT WE CLAIM IS: 1. A free-wheel coupling device of the type comprising a guide cage for a plurality of wedging elements disposed between a cylindrical track and a ring equipped with a series of ramps against which the wedging elements are thrust to lock the device, for a given direction of relative rotation between the track and the ring, by means of an elastic connection between the cage and the ring carrying the ramps, characterised in that the elastic connection is formed by at least one radial projection on the cage which directly or indirectly elastically bears against a generally radial surface of the ramped ring.

2. A device according to claim 1, characterised in that the or each radial project tion is an integral part of the cage.

3. A device according to claim 1, characterised in that the or each radial projection is attached to the cage.

4. A device according to any one of claims 1 to 3, characterised in that ramped ring forms either the inner ring or the outer ring of the device.

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

Claims

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

the outer ring 7 having attached thereto or integral therewith a track having a circular series of wedging ramps 11.

The cage 1 is shown in more detail in Fig. 4, can be metallic or of synthetic material, and has a radial projection 13, that is preferably curved and, in the case of a metallic cage, formed by bending out of the cage a tab that, preferably, has a slight curvature towards the interior of the cage. Such a tab 13 may be ;;r shaped or of any other form that can be obtained by cutting and bending of cage material normally removed to form a pocket 2', which preferably will be without a wedging element, the projection or tab 13 being intended to come into elastic abutment, through the intermediary of an elastic member consti tuted by a spring 17 for example (Fig. 3), against the radial wall 18 of a generally axial groove 21 formed in the ring 7. The spring

17 being at least partially inserted in the groove 21.

Fig. 3 shows the form and manner of connection of the spring 17 which is generally "hat" shaped, the cage projection 13 bearing upon the central convex part 19 of the spring to ensure that the wedging elements 3 are thrust into the locking position.

As known, the device according to the invention is intended to ensure the driving, by a driving shaft made fast by any means with the inner ring 5, of a shaft or any other driven member made fast with the outer ring, for a given direction of rotation of the driving shaft.

In fact, the rotation in the anti-clockwise direction of the inner ring 5, by virtue of the cosperation of the cage 1 and the spring 17, ensures wedging of the elements 3 against the ramps 11 and consequent driving of the outer ring 7.

Rotation of the inner ring 5 in the opposite direction pushes the wedging elements back towards the bottoms 22 of the ramps where the elements can no longer effect transmission of movement to the outer ring.

In order to obtain better balancing of the device, the cage may have certain pockets empty, for example three pockets staggered by 120 , at least one of which has a tab 13 projecting radially therefrom.

Fig. 5 shows an alternative embodiment to that shown by Fig. 3, in which the cage 1 is made of a material possessing the necessary flexibility and resilience permitting the radial projection or tab 13 to fulfil the elastic function of the spring 17.

In fact, this figure shows a flexible tab 13 (drawn in dotted lines in Fig. 4) of generally curved or facetted form having one and preferably two arms 23 contacting the radial wall 18 of the groove 21 into which it is inserted. Such an arrangement provides direct elastic connection of the cage with the ring 7 ensuring that the wedging elements 3 are thrust into the locking position without the use of a separate spring.

It is also possible to provide a cage equipped with two or more radial projections 13 in regular or irregular distribution co-operating with respective radial ring surfaces either directly or via elastic members inserted into axial grooves possessing the same distribution in the ramped ring. In an extreme case, as many cage radial projections 13 and ring radial surfaces 18, with or without intermediary springs 17, can be provided as the cage comprises pockets. In this case, the pockets having radial projections 13 would also have to have wedging elements 3.

The radial surfaces can be formed by axial shoulders separating successive ramps in the ring 7.

In the above examples, the projection 13 has been described as being an integral part of the cage 1 which could be formed by any part of the latter such as a bar, an edge or even an extremity when an open cage is used.

The projection 13 could equally be formed by a separate piece attached, for example by welding, to the cage.

The rings are preferably machined or sintered but it is possible for at least one ring, and more particularly the one having a ramped track, to be obtained by a cold deformation process such as stamping for example.

The wedging elements could be balls instead of needles or rollers.

Finally, the devices described can be reversed by the use of an inner ring equipped with wedging ramps and at least one radial surface co-operating with a cage equipped with a radial projection inturned towards the axis of the device.

WHAT WE CLAIM IS: 1. A free-wheel coupling device of the type comprising a guide cage for a plurality of wedging elements disposed between a cylindrical track and a ring equipped with a series of ramps against which the wedging elements are thrust to lock the device, for a given direction of relative rotation between the track and the ring, by means of an elastic connection between the cage and the ring carrying the ramps, characterised in that the elastic connection is formed by at least one radial projection on the cage which directly or indirectly elastically bears against a generally radial surface of the ramped ring.
2. A device according to claim 1, characterised in that the or each radial project tion is an integral part of the cage.
3. A device according to claim 1, characterised in that the or each radial projection is attached to the cage.
4. A device according to any one of claims 1 to 3, characterised in that ramped ring forms either the inner ring or the outer ring of the device.
5. A device according to any one of claims 1

to 4, characterised in that the ring or the track has radial flanges mounted thereon and forming axial guiding shoulders for the wedging elements.
6. A device according to any one of claims 1 to 5, characterised in that the ring or the track has integral radial shoulders to axially guide the wedging elements.
7. A device according to any one of claims 1 to 6, characterised in that the or each cage radial projection is resiliently flexible and bears, at least in part, directly against the associated radial surface of the ramped ring.
8. A device according to any one of claims 1 to 6, characterised in that an elastic member is disposed between the or each radial cage projection and the associated radial ring surface.
9. A device according to claim 2 and any of claims 4 to 8 when dependent thereon, characterised in that the or each radial projection is a tab bent from the cage.
10. A device according to any one of the previous claims, characterised in that the or each radial ring surface is formed by the radial wall of an axial groove or shoulder in the ring.
11. A device according to any one of the previous claims, characterised in that the wedging elements are rollers, needles or balls.
12. A free-wheel device substantially as described with reference to or as shown by Figs. 1 to 4 or Fig. 5 of the accompanying drawings.