WO2019012396A1

WO2019012396A1 - An improved one way clutch bearing and method of manufacturing thereof

Info

Publication number: WO2019012396A1
Application number: PCT/IB2018/055010
Authority: WO
Inventors: Vishal MAKWANA
Original assignee: Texspin Bearings Limited
Priority date: 2017-07-11
Filing date: 2018-07-06
Publication date: 2019-01-17
Also published as: CN110914564A; JP2020526724A

Abstract

A one way clutch bearing is disclosed, comprising an outer ring 11b and an inner ring 12 with rollers 13 disposed between them. Rollers are backed by springs 15 for their engagement with outer periphery of inner ring 12 such that the rollers 13 allow inner ring to idly rotate in a first direction, but enable transmit of torque, through a cam action, to outer ring when rotated in the opposite direction. A plurality of cam pins 14, which incorporate a cam profile 141, are held within a plurality of pockets 113 located on inner periphery of the outer ring for a corresponding roller to engage with and provide cam action to enable transmit of rotational torque to the outer ring. Each of the pockets 113 and the cam pins 14 are shaped that allows the cam pins to be held in the corresponding pockets without other fixing means.

Description

AN IMPROVED ONE WAY CLUTCH BEARING AND METHOD OF

MANUFACTURING THEREOF

FIELD OF INVENTION:

The present invention relates to an improved one way clutch bearing of roller type and method of manufacturing thereof. More particularly present invention relates an improved one way clutch bearing; which is a light weight single piece assembly, is easy to manufacture and is cost effective. Further, said improved one way clutch bearing do not allow a roller to dislodge from its position. Furthermore, process of manufacturing of improved one way clutch is highly consistent, have high production rate and is cost effective.

BACKGROUND OF THE INVENTION:

One way clutch of roller type widely used in automotive industry as a torque transmitting or back stop device. Majorly it is used with starter motor of engine in automobile to start the engine.

As shown in Fig. l typically used one way clutch 1A of roller type is comprised of an outer ring 10 including pockets 103, cam surface 102, holes 101 and projections 104 disposed inwardly in a radial direction and extending toward an inner ring 12, the inner ring 12 disposed in concentric with the outer ring 10, a plurality of rollers 13 disposed between an outer surface of the inner ring 12 and cam surfaces 102 of the outer ring 10 and adapted to transmit torque. These rollers are tangentially spring loaded by accordion spring 15 or helical spring (not shown). Further, said holes 101 have counter bore to accommodate head of the mounting bolt.

As shown in Fig. 1 the one way clutch assembly 1A, the inner ring 12 can only be rotated in one direction with respect to the outer ring 10 by means of a cam mechanism constituted by the rollers 13 and the cam surfaces 102 of the outer ring 10. That is to say, the inner ring 12 is designed to idly rotate relative to the outer ring 10 in one direction, and on the other hand, it applies rotational torque to the outer ring via the cam mechanism only in an opposite direction. In the one way clutch 1A of roller type, to obtain positive engagement, rollers 13 as torque transmitting members and springs 15 for biasing the rollers 13 are disposed in respective pockets 103 provided in the outer ring 10.

However, the conventional one way clutch imparts following disadvantages:

• Generally the outer ring 10 is made from forged steel. The internal shape is machined; which is very cumbersome process as the shape includes cam profile 102 and projections 104. Further the machining process is a time consuming process.

• Further the opening al of pockets 103 is larger than diameter of roller, which allows the roller 13 to dislodge radially.

• Yet further, there is a possibility of spring 15 to get in contact with inner ring 12, which wears out the spring 15 and failure of one way clutch occurs.

• Yet further the projection 104 has thickness equal to 105-110% of roller length to accommodate roller 13 and spring 15 in pockets 14, which thereby makes it bulky and expensive.

• Yet further as the thickness of projection is high the mounting hole 101 and counter bore needs to be machined, whereas the machining process is cumbersome, time consuming and expensive process.

Thus, there is a need to provide assembly that obviates the problems of the conventional assembly.

PRIOR ARTS AND ITS DISADVANTAGES:

To overcome the issue of roller dislodging, to reduce weight, to minimize the complexity of machining and to increase productivity many attempts has been made; • US patent 8931609 describes a method of manufacturing one way clutch such that roller do not dislodged from its position. Said invention comprises of cylindrical cage with windows to accommodate rollers.

• However, said device includes machining of pockets which is time consuming and expensive process. Further as the thickness of projection is higher, the mounting holes and counter bore of the hole needs to be machined which is cumbersome, time consuming and expensive process.

• US patent 2011/0108382 describes a method of manufacturing one way clutch such that machining complexity reduced by providing pillars, in place of projections, on one of the flange.

• However, said method comprises of spot-welding and complex machining of pillars, which is not desirable for mass production.

• US patent 2002/0148696 describes the device to manufacture one way clutch by stacking piece of blanked sheets to reduce machining complexity and to reduce total size of product.

• However, said device fails to prevent dislodging of roller from its position. It fails to provide adequate dimensional accuracy of sheet stacking and thus is not used in general practice.

• US patent 4106602 describes a method of manufacturing the one way clutch such that product is economical as material saved by gripping elements. By providing gripping element the projections are eliminated.

• However, said device fails to prevent the roller from falling out of one way clutch assembly.

Therefore, available prior arts teaches about the one way clutch that suffers from the disadvantages of dimensional inaccuracy and non-positive engagement, which leads one way clutch bearing to deteriorate from its functioning and that are manufactured produced by means of relatively complex and expensive manufacturing processes. OBJECTS OF THE PRESENT INVENTION:

The main object of present invention is to provide an improved one way clutch bearing; which is a light weight single piece assembly, is easy to manufacture and is cost effective. Another object of present invention is to provide an improved one way clutch bearing as a single piece assembly; wherein the outer ring made from sheet metal working, cold forging or hot forging process.

Still another object of the present invention is to provide an improved one way clutch bearing, wherein said pockets are made from press operation like piercing, blanking or fine blanking which is highly consistent, have high production rate and is cost effective.

Still another object of present invention is to provide an improved one way clutch bearing as a single piece assembly; wherein pockets are so designed that rollers do not dislodged radially.

Still another object of the present invention is to provide an improved one way clutch bearing, wherein top cover and bottom plate are positively locked with outer ring such that rollers and spring do not dislodged axially.

Still another object of the present invention is to provide an improved one way clutch bearing, wherein said cam mechanism is provided by cam-pin and rollers.

Still another object of the present invention is to provide an improved one way clutch; wherein said cam-pin is made by sheet metal working or cold forging operation which is highly consistent, have high production rate and is cost effective.

Still further object of the present invention is to provide an improved one way clutch bearing, wherein projection prevents the spring to be in contact with rotating inner ring thereby prevents it from being wear-out. Yet the object of the present invention is to provide an improved one way clutch bearing; which is light weight single piece assembly, do not have issue of roller dislodging, easy to manufacture, highly consistent, have high production rate and is cost effective. SUMMARY OF THE INVENTION

Aspects of the present disclosure relate to a one way clutch bearing, said bearing comprising: an outer ring; an inner ring; and a plurality of rollers disposed in space between an inner periphery of the outer ring and an outer periphery of the inner ring. Each of the rollers is backed by a spring for engagement of the rollers with the outer periphery of the inner ring such that the plurality of rollers allow the inner ring to idly rotate with respect to the outer ring in a first direction, but enable transmit of torque, through a cam action, to the outer ring when the inner ring is rotated relative to the outer ring in a second direction that is opposite to the first direction. In an aspect, the bearing further comprises: a plurality of cam pins, there can be one cam pin corresponding to each of the rollers, each of the cam pins can incorporate a cam profile for the corresponding roller to engage with and provide said cam action to enable transmit of rotational torque to the outer ring. In another aspect, the plurality of cam pins can be held within a plurality of pockets there being one pocket for each of the cam pins, located on the inner periphery of the outer ring.

In an aspect, each of the pockets and the cam can be shaped that allows the cam pins to be held in the corresponding pockets without other fixing means. In an aspect, the bearing can further comprise a top cover and a bottom plate. The top cover and the bottom plate can be designed to fit on a top side and a bottom side of the outer ring, respectively. Further, the top cover and the bottom plate can by prevent axial displacement of the plurality of cam pins and thus help in retaining them in position with the outer ring. In an aspect, the outer ring, the top cover and the bottom plate can incorporate plurality of holes for mounting purpose. In an aspect, the bottom side of the outer ring can incorporates a circular recess, and the bottom plate can be fitted in the recess of the outer ring by an interference fit.

In an aspect, the top cover can be designed to wrap around the top side and outer periphery of the outer ring, and can be fixed by at least one of crimping and caulking operation.

In an aspect, the plurality of pockets are defined by a plurality of projections. The projections can be radially inward projections extending from the inner periphery of the outer ring towards centre of the outer ring. Thus, each of the pockets can be located between two adj acent proj ections.

In an aspect, thickness of the projections can be substantially less than thickness of the outer ring, therby saving material and reducing weight of the bearing. In an aspect, thickness of the cam pins can be substantially same as thickness of the outer ring, but can be less than the thickness of the outer ring so that fitment of the bottom plate can be done in the recess on the bottom side of the outer ring.

In an aspect, thickness of the plurality of projections can be 30 - 50% of length of the rollers.

In an aspect, the projections can be shaped to provide an opening in the pockets, which can be located near the outer periphery of the inner ring so that the corresponding roller can engage with the outer periphery of the inner ring through the opening. In an embodiment the opening can be 5-10% smaller than diameter of the rollers. The opening being smaller than the roller diameter can prevent radial dislodging of the rollers when the inner race is not in position.

In an aspect, the cam pins can incorporate an outer face that is convex and has a curvature matching the inner periphery of the outer ring for the plurality of the cam pins to rest against the inner periphery of the outer ring. The cam pins can also have a spring seating face for one end of the spring to rest against. The cam pins can further have an inner face opposite the outer face that incorporates a cam profile to provide said cam action to the corresponding roller to enable transmit the rotational torque to the outer ring. In an alternate arrangement of the cam pins, the cam pins can be shaped such that the one end of the spring rests against a side of the corresponding pocket. BRIEF DESCRIPTION OF THE DRAWINGS:

Fig. 1 discloses the top view of conventional one way clutch bearing.

Fig. 2 discloses the fragmentary view of present invention of improved one way clutch bearing.

Fig. 3 discloses sectional the first step of manufacturing of outer ring of improved one way clutch bearing.

Fig. 4 discloses sectional the second step of manufacturing of outer ring of improved one way clutch bearing.

Fig. 5 discloses the final step of manufacturing of outer ring of improved one way clutch bearing. Fig. 6 discloses the top view of present invention of improved one way clutch bearing.

Fig. 7 discloses the sectional view of present invention of improved one way clutch bearing.

Fig. 8 discloses the sectional view of second embodiment of present invention showing cam- pin, roller, spring and pockets.

Fig. 9 discloses the sectional view of third embodiment of present invention showing cam- pin, roller, spring and pockets. Reference numerals used for various parts of the invention:

1 Present improved one way clutch bearing

1A Conventional One way clutch assembly

10 Conventional outer ring

101 Holes

102 Cam profile

103 Pockets

104 Projections 11 Raw piece of Improved outer ring

11a Semi finish improved outer ring

l ib Improved outer ring

111 Guide surface

112 Under groove

113 Pockets

113a Pockets of second embodiment

113b Pockets of third embodiment

114 Projections

115 Holes

116 Inner peripheral face of pockets

117 Peripheral face

12 Inner ring

121 Outer face of inner ring

13 Rollers

14 Cam-pin

14a Cam-pin of second embodiment

14b Cam-pin of third embodiment

141 Cam profile

141a Cam profile of second embodiment

141b Cam profile of third embodiment

142 Outer face

143 Spring seating face

15 Spring

16 Top cover

161 Holes of top cover

17 Bottom plate

171 Holes of bottom plate

DETAILED DESCRIPTION OF THE PRESENT INVENTION:

The present invention An Improved One Way Clutch Bearing and Method of Manufacturing Thereof 1 provides an improved one way clutch bearing of roller type and a method for manufacturing it, wherein said improved one way clutch bearing; is a light weight single piece assembly, which is easy to manufacture and is cost effective. Further, process of manufacturing of improved one way clutch is highly consistent and have high production rate. Referring to Fig. 1 to Fig. 9 an embodiment of the present invention provides an improved one way clutch bearing wherein said improved one way clutch bearing 1 mainly comprises of:

• Outer ring lib

• Inner ring 12

• Rollers 13

• Cam-pin 14

• Spring 15

• Top cover 16

• Bottom plate 17

Said outer ring lib further comprises of guide surface 111, under groove 112, pockets 113 and projections 114, extended inwardly in radial direction, and holes 115 for mounting the one way clutch bearing 1 on rotor (not shown).

Said cam-pin 14 is provided to constitute said cam mechanism between roller 13, cam-pin 14 and inner ring 12 and further comprises of outer face 142, spring seating face 143 and cam- profile 141. Said outer face 142 is provided to accommodate cam-pin 14 in pockets 113, wherein said outer face 142 of cam-pin 14 has the radius R similar to the radius R of inner peripheral face 116 of pockets 113. Said the inner face 116 of pocket 113 is provided at extreme inner peripheral face 117 of outer ring lib to provide full support to the outer face 142 of cam-pin 14. The rollers 13 are tangentially spring loaded by spring 15.

Referring to fig.6, said spring 15 is provided for biasing the roller 13 and is located between roller 13 and spring seating face 143 of cam-pin 14 in respective pockets 113 of outer ring lib. Said rollers 13 are placed such that they are engaged by cam surfaces 141 of cam-pins 14 and outer face 121 of inner ring 12 and there by provides a condition where the said one way clutch bearing 1 is locked in one direction. As can be seen from Fig. 6. The cam pins 14 are held within the pockets 113 without any additional means for fixing the cam pins 14. They are retained in the corresponding pocket 113 on account of matching profiles of the two. Referring to Fig.7, said roller 13 and spring 15 are located between the cam-pin 14 and inner ring 12, wherein the thickness of the said projections 114 is kept 30-50% of the roller length, which thereby reduces the weight and cost of the present one way clutch bearing. Further, the projections 114 are so designed that opening of pocket 113 is 5-10% smaller than that of the roller 13 diameter, as shown in Fig. 6, to prevent the roller 13 to dislodge radially from its position. Moreover, the projection 114 prevents the spring 15 to be in contact with outer face 121 of inner ring 12, which thereby prevents said spring 15 from any wear. Said top cover 16 made from sheet steel joined with outer ring lib attached by methods that includes crimping, caulking or alike positive engagement method. Said top cover 16 and bottom plate 17 comprises of holes 161 and 171 for mounting purpose. Said bottom plate 17 consists of interference fit with guide surface 111 and have clearance fit with under groove 112, so that it can be fix in outer ring lib. Further, the bottom plate 17 can be mechanically locked with outer ring lib.

Referring to Fig. 6 and Fig. 7, the present one way clutch bearing 1, is provided in form of a single unit which further prevents said roller 13 and spring 15 to get dislodged from its position and there by provides a one way clutch bearing. Another alternative to the present one way clutch bearing is by providing a sealing to the said inner periphery of top cover 16 and bottom plate 17 to reduce the accumulation of foreign particles in pockets 114 as top cover 16 and bottom plate 17 are fixed with outer ring lib.

Present embodiment serves all the aspects of one way clutch of roller type yet is light in weight, easy to manufacture, highly consistent, have high production rate and is cost effective. METHOD OF MANUFACTURING IMPROVED OUTER RING:

Referring to Fig.3 the present one way clutch bearing 1 consists of an improved outer ring lib made from sheet steel or forged steel, wherein the best method for manufacturing the improved outer ring is as follows: a. Referring to Fig.3, said raw piece 11 of improved outer ring lib, made from sheet metal working or forging process. b. Said outer ring 11 is then machined by turning operation, as shown in Fig. 4, to get outer ring 11a which comprises of guide face 111 and under groove 112 to fix bottom plate 17. Said outer ring 11a alternatively made from sheet metal working, eliminating the first step, which is highly consistent, and has high production rate and is cost-effective process. c. After machining of outer ring 11a the pockets 113, the projections 114 and holes 115 are formed by piercing, blanking or fine blanking process. Wherein due to piercing, blanking or fine blanking process, forming of complex shape is done reliably and quickly, which further improves consistency and production rate. Thereby machining of mounting holes and counter bore is eliminated. d. After blanking, piercing or fine blanking process operation the outer ring lib is subjected to hardening process in case of high torque transmission application.

METHOD OF MANUFACTURING CAM-PIN:

Said cam-pin 14 is provided to constitute said cam mechanism between rollers 13, cam-pin 14 and inner ring 12, wherein the best method to manufacture the cam-pin 14 of the present one way clutch bearing 1 is through: a. said cam-pin 14 is made from rectangular strip or rectangular bar of steel by press operation or cold forging process, thereby achieving high consistency and high production rate; b. said cam-pins 14 is further subjected to hardening process; wherein in case of low torque transmission the hardening of outer ring lib is not needed thereby reduces the manufacturing cost. OTHER EMBODIMENTS OF PRESENT INVENTION:

i) Second embodiment of present invention:

Another embodiment of present invention is as shown in Fig. 8. This embodiment comprises of:

• Outer ring lib

• Inner ring 12

• Rollers 13

• Cam-pin 14a

• Spring 15

• Top cover 16

• Bottom plate 17,

Wherein,

Said outer ring lib further comprises of guide surface 111, under groove 112, pockets 113a, modified as per cam-pin 14a, and projections 114, extended inwardly in radial direction, and mounting holes 115.

Said cam-pin 14a comprises of outer face 142 and cam-profile 141. Said cam-pin 14a does not consists of spring seating face 143 like as described in main embodiment. Said outer face 142 is same as described in main embodiment. The rollers 13 are tangentially spring loaded by spring 15. Said spring 15 is accommodated between roller 13 and pockets 113a, wherein the opening of pocket 113a is kept 5-10% smaller than that of roller length to prevent the roller 13 to dislodge from its position. Also, the top cover 16 and bottom plate 17 are fixed with outer ring lib as described in main embodiment, which thereby provides a single piece assembly of one way clutch bearing. ii) Third embodiment of present invention: Another embodiment of present invention is as shown in Fig. 9. This embodiment comprises of:

• Outer ring lib

• Inner ring 12

• Rollers 13

• Cam-pin 14b

• Spring 15

• Top cover 16

• Bottom plate 17,

Wherein,

Said outer ring lib further comprises of guide surface 111, under groove 112, pockets 113b, modified as per cam-pin 14b, and projections 114, extended inwardly in radial direction, and mounting holes 115.

Said cam-pin 14b comprises of outer face 142 and cam-profile 141b. Said cam-pin 14b consists of alternative of cam profile 141b as shown in Fig. 9. Said outer face 142 is same as described in main embodiment. The rollers 13 are tangentially spring loaded by spring 15. Said spring 15 is accommodated between roller 13 and pockets 113b, wherein the opening of pocket 113b is kept 5-10% smaller than that of roller length to prevent the roller 13 to dislodge from its position. Also, the top cover 16 and bottom plate 17 are fixed with outer ring lib as described in main embodiment, which thereby provides a single piece assembly of one way clutch bearing.

As can be seen from Figs. 8 and 9, in case of alternate embodiments of the one-war bearing also, the cam pins 14a /14b are held within the corresponding pockets 113a/113b without any additional means for fixing the cam pins 14a /14b. They are retained in the corresponding pockets 113a/113b on account of matching profiles of the two. The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

ADVANTAGES OF THE INVENTION:

There are many advantages of the present invention over prior art and conventional:

1. Present invention provides improved one way clutch bearing in single unit.

2. Present invention provides improved one way clutch bearing; in which the problem of dislodging of roller and spring is eliminated.

3. Present invention provides improved one way clutch bearing; wherein the problem of spring wear is eliminated.

4. Present invention provides improved one way clutch bearing which is light in weight, easy to manufacture, highly consistent, have high production rate and is cost effective.

Claims

We Claim:

1. A one way clutch bearing, said bearing comprising:

an outer ring;

an inner ring;

a plurality of rollers disposed in space between an inner periphery of the outer ring and an outer periphery of the inner ring, the plurality of rollers backed by a plurality of springs for the plurality of the rollers to engage with the outer periphery of the inner ring such that the plurality of rollers allow the inner ring to idly rotate with respect to the outer ring in a first direction, but enable transmit of torque, through a cam action, to the outer ring when the inner ring is rotated relative to the outer ring in a second direction that is opposite to the first direction;

wherein, the bearing further comprises:

a plurality of cam pins, there being one cam pin corresponding to each of the plurality of rollers, each of the cam pins incorporating a cam profile for the corresponding roller to engage with and provide said cam action to enable transmit of rotational torque to the outer ring; wherein the plurality of cam pins are held within a plurality of pockets there being one pocket for each of the cam pins, located on the inner periphery of the outer ring.

2. The bearing as claimed in claim 1, wherein each of the pockets and the cam pin are shaped that allows the cam pins to be held in the corresponding pockets without other fixing means.

3. The bearing as claimed in claim 1, wherein the bearing further comprises a top cover and a bottom plate, the top cover and the bottom plate adapted to fit on a top side and a bottom side of the outer ring, respectively; the top cover and the bottom plate adapted to hold the plurality of cam pins with the outer ring by preventing axial displacement of the plurality of cam pins.

4. The bearing as claimed in claim 3, wherein the outer ring, the top cover and the bottom plate incorporate plurality of holes for mounting purpose.

5. The bearing as claimed in claim 3, wherein the bottom side of the outer ring incorporates a circular recess, and the bottom plate is fitted in the recess of the outer ring by an interference fit.

6. The bearing as claimed in claim 3, wherein the top cover is adapted to wrap around the top side and outer periphery of the outer ring and fixed by at least one of crimping and caulking operation.

7. The bearing as claimed in claim 1, wherein the plurality of pockets are defined by a plurality of projections, said projections being radially inward projections extending from the inner periphery of the outer ring towards a centre of the outer ring such that each of the pockets is located between two adjacent projections out of the plurality of projections.

8. The bearing as claimed in claim 7, wherein thickness of the plurality of projections is substantially less than thickness of the outer ring.

9. The bearing as claimed in claim 5, wherein thickness of the plurality of cam pins is substantially same as thickness of the outer ring allowing for fitment of the bottom plate in the recess on the bottom side of the outer ring.

10. The bearing as claimed in claim 8, wherein thickness of the plurality of projections is 30 - 50% of length of the plurality of rollers.

11. The bearing as claimed in claim 7, wherein the plurality of projections are shaped to provide an opening in the plurality of pockets, the opening located near the outer periphery of the inner ring for the corresponding roller to engage with the outer periphery of the inner ring; and wherein the opening is 5-10% smaller than diameter of the plurality of rollers to prevent radial dislodging of the rollers.

12. The bearing as claimed in claim 1, wherein the plurality of cam pins incorporate: an outer face that is convex and having a curvature matching the inner periphery of the outer ring for the plurality of the cam pins to rest against the inner periphery of the outer ring;

a spring seating face for one end of the spring to rest against; and

an inner face opposite the outer face and incorporating a cam profile to provide said cam action to the corresponding roller to enable transmit of rotational torque to the outer ring.

13. The bearing as claimed in claim 1, wherein the plurality of cam pins incorporate:

an outer face that is convex and having a curvature matching the inner periphery of the outer ring for the plurality of the cam pins to rest against the inner periphery of the outer ring; and

an inner face opposite the outer face and incorporating a cam profile to provide said cam action to the corresponding roller to enable transmit of rotational torque to the outer ring;

wherein one end of the spring rests against a side of the corresponding pocket.