FR3038021A1 - PULLEY DEVICE FOR TILT ROLLER OR ROLLER - Google Patents

Abstract

The pulley device comprises a pulley 12, a mounting body 18 supporting the pulley and provided with a bore 18a therethrough, and a fastening screw 20 provided with a rod 42 extending inside said bore and a head 44. The rod 42 of the fixing screw comprises an annular groove 50 and at least one axial groove 52 opening into said groove. The mounting body 18 comprises at least one protuberance 54 integral with said body and projecting into said groove 50 for axial retention of the fixing screw relative to the mounting body.

Description

The present invention relates to the field of pulley devices for tensioner or retractor roller provided to cooperate with a chain or a belt, for example a motor vehicle internal combustion engine timing belt. Such rollers are generally used to permanently maintain a tension on the belt or chain in a specific range or to locally change the path taken by it. These are then called tensioning rollers or rollers. In the rollers, the pulley is rotatably mounted on a screw or a shaft via a bearing, the roller being then attached directly or indirectly to the engine block or to a member of a tensioner device, for example an articulated arm or an eccentric. To achieve the fixing of the roller on its support, one can use a spacer in association with said screw. During this assembly, it is desirable for the screw to be axially integral with the other elements constituting the roller and comprising the pulley. This provides a set that is indémontable, easy to handle and transport, and can be mounted easily. For this purpose, document FR 2 954 437 discloses a pulley device comprising a pulley, a bearing, a spacer supporting the bearing and a fixing screw immobilized axially with respect to the spacer. The axial retention of the screw relative to the spacer is achieved by means of a retaining ring radially interposed between them. The retaining ring is housed partly inside a groove specifically provided on the fixing screw. To achieve the mounting of the retaining ring, this solution requires the provision of a groove or annular clearance of relatively large size on a front surface of the spacer. However, this front surface is used to achieve the attachment of the device on the associated support. This therefore considerably reduces the contact area between the spacer and this support.

The present invention aims to remedy this disadvantage. More particularly, the present invention aims to provide a pulley device easy to manufacture, to assemble and economic. In one embodiment, the pulley device for a tensioner or belt or chain winder comprises a pulley, a mounting body supporting the pulley and provided with a through bore, and a fixing screw provided with a rod. extending inside said bore and a head. The rod of the fixing screw comprises an annular groove and at least one axial groove opening into said groove. The mounting body comprises at least one protuberance integral with said body and projecting within said groove to provide axial retention of the fastening screw relative to the mounting body. Thus, the axial retention of the screw relative to the mounting body is achieved without the interposition of a retaining ring freely mounted between said screw and said mounting body and which requires to provide a large clearance on the front surface of the body mounting used to achieve the attachment of the device on the associated support. This makes it possible to increase the area of contact between this front surface of the mounting body and the support. The device forms a unitary assembly that can be stored, transported and mounted with a risk of accidentally separating the elements constituting it particularly weak. Furthermore, when a tightening torque is exerted on the screw 25 to fix the device on the associated support, the screw can rotate freely in view of the annular shape of the groove. This avoids having to exert additional tightening torque. Preferably, the mounting body comprises two end surfaces axially delimiting said bore, at least the front surface located axially opposite the head of the fixing screw is smooth. The term "smooth" means a face devoid of projections, pins, asperities, ribs, etc. or grooves or recesses, etc. This design further increases the contact area 3038021 between this front surface of the mounting body and the support. The annular groove and said groove are advantageously formed on the outer surface of the fixing screw. Preferably, said screw groove extends from a distal end of the shaft axially opposite the head. Said groove may extend along a threaded portion and a smooth portion of said screw. The smooth portion may include the annular groove.

In one embodiment, the annular groove is defined axially at least by a lateral edge oriented axially towards the head of the fixing screw and adapted to cooperate by contact with said protuberance of the mounting body. Said protrusion can extend inwards from the bore of said body.

In one embodiment, the device comprises a spacer forming the mounting body and a bearing interposed between said spacer and the pulley. In another mode, the bearing may be devoid of the spacer and a bearing ring forms said mounting body.

The present invention will be better understood on studying the detailed description of an embodiment taken by way of non-limiting example and illustrated by the appended drawings, in which: FIG. 1 is an axial sectional view of FIG. A pulley device according to an exemplary embodiment, FIG. 2 is a perspective view of a fixing screw of the device of FIG. 1, and FIG. 3 is a front view of a spacer of the device. In Fig. 1, the pulley device for tensioner or belt or chain winder, referenced as a whole, comprises a pulley 12, a rolling bearing 14 supporting the pulley, of geometric axis 16, a spacer 18 and a fixing screw 20 coaxial with the axis 16. As will be described in more detail below, the fixing screw 20 and the spacer 18 each comprise a means to ensure their axial retention. relative. The pulley 12 includes an outer axial portion 24 having an outer surface for cooperating with a belt or chain (not shown), an inner axial portion 26 and a radial annular intermediate portion 28 connecting said portions. The outer 24 and inner 26 portions are coaxial with the axis 16. Ribs (not referenced) of stiffening are also provided between the outer 24 and inner axial portions 26 and are connected to the intermediate portion 28. The rolling bearing 14 comprises an inner ring 30, an outer ring 32 on which is mounted the pulley 12, a row of rolling elements 34, here made in the form of balls, arranged between the races of the rings, and a cage 36 ensuring the maintenance the circumferential spacing of the rolling elements 34. The bearing 14 also comprises on each side an annular seal (not referenced) fixed on the outer ring 32 to close the radial space existing between the rings and inside which The rolling elements 34 and the cage 36 are housed. In the exemplary embodiment shown, the inner and outer rings 30 and 30 are massive. In the exemplary embodiment illustrated, the pulley 12 is obtained by overmolding on the outer ring 32 of a plastic material, such as a polyamide. This results in excellent cohesion between these 25 pieces. Alternatively, the pulley could be glued to the outer ring 32, or be made of sheet metal and be fitted on said ring. In another variant, the pulley and the outer ring could be made in one piece. The spacer 18, with axis 16, supports the bearing 14. The inner ring 30 of the bearing is mounted on the spacer 18. The bearing 14 is distinct from the spacer 18. The spacer 18 extends axially in protrusion relative to the pulley 12. The spacer 18 comprises an outer cylindrical axial surface 18a, a cylindrical bore 18b, with an axis 16, and two opposite end faces 18c, 18d radially radially defining said bore and the outer surface. In the exemplary embodiment illustrated, the front surfaces 18c, 18d form end surfaces of the spacer. The outer surface 18a of the spacer has a stepped shape defining an annular radial shoulder 38 forming an abutment surface for the inner ring 30 of the bearing. One of the end surfaces of the inner ring bears axially against the shoulder 38. The outer surface 18a of the spacer comprises a first portion on which is mounted the inner ring 30 of the bearing and a second portion of larger diameter, said portions being interconnected by the shoulder 38. In the exemplary embodiment illustrated, the front surface of the inner ring, situated axially opposite the shoulder 38, is slightly projecting with respect to the front surface. 18c of the spacer. The spacer 18 leaves this radial surface 15 completely free so that it can be used as a reference surface and bear against another surface. The radial surface 18d of the spacer is provided to bear against an external support (not shown) to the device 10 to allow mounting and fixing the device on this support.

The support may for example be the engine block, an articulated arm or an eccentric of the associated automatic tensioner roller. The radial surface 18d is completely smooth. The bore 18b of the spacer extends axially from the front surface 18c to the radial surface 18d. Bore 18b is through. The fixing screw 20 extends inside the bore 18b. The screw 20 can be adjusted with a radial clearance more or less important in the bore 18b. The fastening screw 20 comprises a head 40 and a rod 42 extending axially from the head. The rod 42 comprises a smooth portion 44 extending axially from the head 40 and a threaded portion 46 opposite said head. The smooth portion 44 is centered in the bore 18b of the spacer. The threaded portion 46 extends in axial projection relative to the front surface 18b of the spacer.

This threaded portion 46 of the screw is adapted to be inserted into a threaded hole formed in the support outside the device. The fixing screw 20 comprises a bearing washer 48 mounted around the rod 42 and against which the head 40 is mounted in contact.

The washer 48 is mounted axially in abutment against the front surface of the inner ring left free by the spacer 18. Alternatively, it could be possible to provide a washer made of material, ie made in one piece, with the rod 42 and the head 40 of the fixing screw.

The fixing screw 20 further comprises an annular groove 50 and an axial groove 52 which opens into said groove (FIG. 2). The groove 50 and the groove 52 are distinct from the thread of the threaded portion 46. The groove 50 and the groove 52 are formed on the rod 42. The groove 50 and the groove 52 are formed on the outer surface of the rod 42. The groove 50 and the groove 52 extend radially inwardly from said outer surface. The groove 50 is formed on the smooth portion 44 of the rod. In the exemplary embodiment illustrated, the groove 50 extends axially from the head 40. The groove 50 is delimited axially by the head 40 and a radial edge 50a 20 axially opposite said head and projecting relative to the bottom of said groove. The edge 50a is discontinuous in the circumferential direction because of the groove 52. The groove 52 extends along the rod 42 until it opens axially into the groove 50. The groove 52 extends parallel to the axis 16. The groove 52 extends here on the threaded portion 46 and the smooth portion 44 of the rod. The groove 52 extends from the distal end of the rod 42 located axially opposite the head 44. The groove 52 is rectilinear. The groove 52 is oriented radially outwards. The groove 52 may have a rectangular, square, circular arc, and so on. The spacer 18 includes a protuberance 54 projecting inwardly with respect to the bore 18a. The protrusion 54 is integral with the spacer. The protrusion 54 extends from the bore 18a radially inwardly. In the exemplary embodiment illustrated, the protrusion 54 is located axially on the side of the head 44 of the fixing screw and locally extends the front surface 18c inwardly. The protrusion 54 is made in one piece with the spacer 18. The protrusion 54 may be formed on the spacer 18 5 by local embossing material. The protuberance 54 is thus obtained by local plastic deformation of the spacer 18. Alternatively, the protuberance 54 can be attached and fixed to the spacer 18 by any appropriate means, for example by gluing, welding, etc. The protuberance 54 extends over a limited angular sector (FIG. 3), for example between 5 ° and 20 °. The protrusion 54 may have in cross section a rectangular, square, arcuate, etc. The protuberance 54 extends projecting inside the groove 50 of the fixing screw. The protrusion 54 is engaged inside the groove 50. The protrusion 54 forms a retaining means 15 cooperating with an associated retaining means formed by the edge 50a of the groove to ensure the axial retention of the fastening screw 20 relatively In fact, in the case of axial displacement of the fixing screw 20 in a direction opposite to a direction of engagement of the screw inside the bore 18, the protuberance 54 comes axially into position. contact against the edge 50a of the groove. The axial displacement of the screw 20 is blocked by interference in the axial direction between the protuberance 54 and the edge 50a. The edge 50a forms an abutment surface for the protuberance 54.

To allow insertion of the fastening screw 20 into the bore 18 of the spacer, the protuberance 54 is shaped so that it can engage and slide along the groove 52. The protuberance 54 preferably has a shape complementary to that of the groove 52.

The operator aligns the groove 52 and the protuberance 54 so as to be able to introduce by axial thrust the fastening screw into the bore 18b of the spacer. The screw 20 is pushed axially to bring the washer 48 axially bearing against the bearing 14. The protrusion 54 of the spacer is then located inside the groove 3038021 8 50 of the screw. The operator then pivots the screw 20 relative to the spacer 18 so as to shift circumferentially the protrusion 54 relative to the groove 52 and prevent extraction of the screw.

As indicated above, the cooperation between the protrusion 54 and the groove 50 makes it possible to block any axial displacement of the fixing screw 20 relative to the spacer 18 in the direction opposite to the insertion direction of the screw. It is then possible to store, transport and manipulate the pulley device with a limited risk of disconnecting the constituent elements without having to provide additional retaining means. In the exemplary embodiment illustrated, the protrusion 54 of the spacer is located axially on the side of the screw head.

Alternatively, it is possible to provide other provisions of the protuberance. For example, it is possible to provide a protuberance located axially in the vicinity of the front surface 18d or flush with said surface. It is understood that the position of the annular groove 50 on the fixing screw is determined by the axial position of the protuberance 54 on the spacer. In the exemplary embodiment illustrated, the annular groove 50 of the fixing screw is delimited axially by the head 40 and the edge 50a. As a variant, the groove may be offset axially with respect to the head 40 and may be defined axially by two axially opposite radial edges.

In the exemplary embodiment illustrated, the head of the fixing screw extends axially beyond the pulley 12. In a variant, it is possible to provide a clearance on the front surface 18c so as to receive at least one part of the head of the fixing screw. The front surface then has a stepped shape. In this case, the fixing screw may be devoid of the support washer. In the exemplary embodiment illustrated, the device comprises the spacer 18 interposed radially between the bearing 14 and the screw. The protrusion is provided on the spacer 18. Alternatively, the device could be devoid of the spacer 18. In this case, the fixing screw 3038021 9 extends directly inside the bore of the inner ring of the bearing. The inner ring includes the retaining protuberance projecting inwardly with respect to the bore of said ring.

In the exemplary embodiments described, a single protuberance 54 is provided on the spacer or on the inner ring of the bearing. Alternatively, it is possible to provide several protuberances on the spacer, or on said ring, spaced relative to each other in the circumferential direction. In this case, the fixing screw 10 comprises a plurality of grooves which each open into the annular groove. The invention has been illustrated on the basis of a pulley device comprising a rolling bearing provided with at least one row of rolling elements disposed between the inner and outer rings.

Alternatively, the bearing may be of the sliding type and consist of a single annular ring, for example made of thermoplastic material, and may include radial grooves capable of being filled with lubricant. In another variant, the sliding bearing may comprise two rings sliding directly on one another.

Claims (10)

REVENDICATIONS1. Pulley device for tensioner roller or belt or chain winder comprising a pulley (12), a mounting body (18) supporting the pulley and provided with a through bore (18a), and a fastening screw (20) provided a rod (42) extending inside said bore and a head (44), characterized in that the rod (42) of the fixing screw comprises an annular groove (50) and at least one axial groove (52) opening into said groove, the mounting body (18) comprising at least one protrusion (54) integral with said body and projecting inside said groove (50) to ensure the axial retention of the fixing screw relative to the mounting body. 2. Device according to claim 1, wherein the mounting body (18) comprises two end faces (18c, 18d) defining axially said bore, at least the front surface (18d) located axially opposite the head (44). ) of the fixing screw is smooth. 3. Device according to claim 1 or 2, wherein the annular groove (50) and said groove (52) are formed on the outer surface of the fixing screw. The device according to any one of the preceding claims, wherein said groove (52) of the fixing screw extends from a distal end of the rod (42) situated axially opposite the head ( 44). Apparatus according to any one of the preceding claims, wherein said groove (52) of the fixing screw extends along a threaded portion (46) and a smooth portion (44) of said screw. 6. Device according to any one of the preceding claims, wherein a smooth portion (44) of the fixing screw comprises the groove (50) annular. 7. Device according to any one of the preceding claims, wherein the annular groove (50) is defined axially at least by a lateral edge (50a) oriented axially towards the head (40) of the fixing screw and adapted to cooperating by contact with said protuberance (54) of the mounting body (18) to provide axial retention of the fixing screw relative to the mounting body. The device of any one of the preceding claims, wherein said protuberance (54) extends inwardly from the bore (18a) of the mounting body. 9. Device according to any one of the preceding claims, comprising a spacer (18) forming the mounting body and a bearing (14) interposed between said spacer and the pulley. 10 10.Device according to any one of claims 1 to 8, comprising a bearing (14) provided with at least one ring which forms said mounting body.