FR3038020A1 - PULLEY DEVICE FOR TILT ROLLER OR ROLLER - Google Patents

Abstract

The pulley device comprises a pulley 12, a bearing 14, a spacer 18 provided with a through bore 18b and two end faces 18c, 18d defining axially said bore, and a fixing screw 20. The spacer comprises an annular groove 40 extending radially from the bore 18b and arranged axially recessed with respect to the front surface 18d situated axially opposite the head 44 of the fixing screw. The fixing screw comprises at least one first retaining means 54 integral with the rod 46 and projecting inside the groove 40. The spacer comprises at least one second retaining means 40a secured to said spacer, extending projecting from a bottom 40c of the groove and adapted to cooperate by contact with said first retaining means 54.

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, a spacer is generally used 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 fixing screw relative to the spacer is carried out by means of a retaining ring radially interposed between them. 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 overcome this drawback 3038020 2 More particularly, the present invention aims to provide a pulley device easy to manufacture, assemble and economic. In one embodiment, the pulley device for a tensioning roller or belt or belt winder comprises a pulley, a bearing, a spacer supporting said bearing and provided with a through bore and two end faces axially delimiting said bore, and a fixing screw comprising a rod extending inside said bore and a head. The spacer comprises an annular groove extending radially from the bore and disposed axially recessed with respect to the front surface located axially opposite the head of the fastening screw. The fixing screw comprises at least one first retaining means secured to the rod of said screw and projecting inside the groove. The spacer comprises at least one second retaining means secured to said spacer, projecting from a bottom wall of the groove and able to cooperate by contact with said first retaining means to ensure the axial retention of the groove. the fixing screw relative to the spacer. Thus, the axial retention of the screw relative to the spacer is achieved without the use of an interposed retaining ring and freely mounted between said screw and said spacer. 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.

In addition, the annular groove is disposed axially recessed from the front surface used for fixing the device to the associated support. This increases the contact area between the front surface of the spacer and the support. On the other hand, when a tightening torque is exerted on the screw 30 to fix the device on the associated support, the first retaining means can freely rotate inside the annular groove. This avoids having to exert additional tightening torque. The retaining means provide only axial retention function of the screw, and not an anti-rotation function. Preferably, at least said front surface of the spacer located axially opposite the head of the fixing screw is smooth.

By "smooth" is meant a face devoid of projections, nubs, asperities, ribs, etc. or grooves or recesses, etc. This design further increases the contact area between the front surface of the spacer and the support. Preferably, the annular groove of the spacer is delimited axially by two opposite lateral edges, the lateral edge disposed axially on the side of the head of the fixing screw forming the second retaining means. Alternatively, the spacer comprises a washer or retaining ring mounted in the groove and forming the second retaining means.

In one embodiment, the annular groove of the spacer is axially recessed with respect to the front surface located axially on the side of the head of the fixing screw. The annular groove does not open on this frontal surface. In one embodiment, the spacer further comprises at least one notch axially open on the side of the front surface located axially on the side of the head of the fixing screw, said notch being open into the groove and being delimited in the circumferential direction by two opposite side edges. Said notch may extend from said front surface.

Said first retaining means of the fixing screw is advantageously shaped so as to be able to pass through said notch when said screw is introduced into the bore. Preferably, the stem of the fixing screw comprises a smooth portion located axially on the side of the head and a threaded portion, said first retaining means being disposed on the smooth portion. In one embodiment, said first retaining means of the fixing screw is made in one piece with said screw. Alternatively, said first fastening means of the fastening screw is attached to said screw, for example by overmolding. With this last solution, said first retaining means can advantageously be made of a softer material than the material of the fastening screw. In one embodiment, the groove of the spacer is located near the front surface of the spacer located axially on the side of the head of the fixing screw. Alternatively, the groove may be located near the opposite side surface of the spacer. The present invention will be better understood on studying the detailed description of embodiments taken by way of non-limiting examples and illustrated by the appended drawings, in which: FIG. 1 is an axial sectional view of a pulley device according to a first exemplary embodiment, - Figure 2 is a sectional view of a spacer of the device of Figure 1, - Figure 3 is a front view of the spacer of Figure 2, - Figure 4 is a side view of a fixing screw of the device of Figure 1, Figure 5 is a front view of the fixing screw of Figure 4, Figure 6 is a sectional view of a spacer of a pulley device according to a second exemplary embodiment; - FIG. 7 is a side view of a fixing screw of a pulley device according to a third exemplary embodiment, and FIG. an axial sectional view of a pulley device according to a fourth example of embodiment we. 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 means for ensuring their relative axial retention.

The pulley 12 comprises an outer axial portion 22 having an outer surface intended to cooperate with a belt or a chain (not shown), an inner axial portion 24 and a radial annular intermediate portion 26 connecting said portions. The outer 22 and inner 24 portions are coaxial with the axis 16. Ribs (not referenced) of stiffening are also provided between the outer axial portions 22 and inner 24 and are connected to the intermediate portion 26. 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 of the circumferential spacing of the rolling elements 34. The bearing 14 also comprises on each side an annular seal 15 (not referenced) fixed on the outer ring 32 to close the radial space existing between the rings and inside. which are housed the rolling elements 34 and the cage 36. The inner ring 30 comprises a cylindrical outer surface (unreferenced) cylindrical on which The inner ring 30 also comprises a cylindrical bore 30a fitted on the spacer 18 and two opposite end faces 30b, 30c radially defining said bore and the outer surface. The outer ring 32 has a similar design. In the exemplary embodiment illustrated, the inner and outer 30 and outer rings 32 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 30 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 The spacer 18 comprises an axial cylindrical outer surface 18a, a cylindrical bore 18b, with an axis 16, and two opposite radial end faces 18c, 18d axially delimiting 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 delimiting an annular radial shoulder 38 forming an abutment surface for the inner ring 30 of the bearing. The front surface 30c 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 30b of the inner ring is slightly protruding from the front surface 18c of the spacer. The spacer 18 leaves the radial surface 30b 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 25 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 smooth. The bore 18b of the spacer extends axially from the front surface 18c to the radial surface 18d. The 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.

As shown more clearly in Figure 2, the spacer 18 includes an annular groove or groove 40 formed on the bore 18b. The groove 40 extends from the bore 18b. The groove 40 extends here radially outwardly from said bore. The groove 40 is located axially recessed from the front surfaces 18c, 18d of the spacer. The groove 40 is shifted inwardly of the spacer relative to these front surfaces 18c, 18d. In the exemplary embodiment illustrated, the groove 40 is located axially close to the front surface 18c. The groove 40 is delimited axially by two opposite radial edges 40a, 40b. The flanges 40a, 40b protrude from the bottom 40c of the groove. In the exemplary embodiment illustrated, the groove 40 has a rectangular cross section in cross section. Alternatively, it is possible to provide other shapes, for example square, arc, etc.

The spacer 18 further comprises a notch 42 which extends axially from the end face 18c and which opens into the groove 40. The notch 42 is open axially on the side of the end face 18c. As illustrated more clearly in FIG. 3, the notch 42 is delimited in the circumferential direction by two opposite lateral edges 42a, 42b facing each other. The notch 42 extends over an angular sector strictly less than 360 °. In the exemplary embodiment illustrated, the notch 42 extends over an angular sector between 40 ° and 50 °. The notch 42 extends axially between the front surface 18c and the groove 40. The notch 42 locally extends the groove 40 and 25 opens on the front surface 18c of the spacer. The edge 40a of the groove is discontinuous in the circumferential direction due to the notch 42. The edge 40b of the groove is annular. Referring again to FIG. 1, the fixing screw 20 comprises a head 44 and a rod 46 extending axially from the head. The rod 46 comprises a smooth portion 48 extending axially from the head 44 and a threaded portion 50 opposite said head. The smooth portion 48 is centered in the bore 18b of the spacer. The threaded portion 50 extends in axial projection relative to the front surface 18b of the spacer. This threaded portion 50 of the screw 3038020 8 is intended to be inserted into a threaded hole formed in the support outside the device. In the exemplary embodiment illustrated, the fixing screw 20 comprises a washer 52 made of material, ie integrally formed, with the rod 46 and the head 44. The washer 52 is mounted axially in abutment against the front surface 30b of the inner ring left free by the spacer 18. Alternatively, it may be possible to provide a separate washer of the screw 20, mounted around the rod 46 and against which is mounted in support of the head 44.

The fixing screw 20 also comprises a protuberance 54 projecting from the rod 46. The protuberance 54 is integral with the rod 46. The protuberance 54 extends from the outer surface of the rod 46. The protrusion 54 extends radially outwards. The protuberance 54 is formed on the smooth portion 48 of the rod. In the illustrated embodiment, the protrusion 54 is located axially in the vicinity of the head 44. The protrusion 54 is formed on the screw 20 by local embossing material. The protuberance 54 is obtained by local plastic deformation of the screw 20.

The protrusion 54 protrudes into the groove 40 of the spacer. The protuberance 54 is engaged within the groove 40. The protrusion 54 forms a retaining means cooperating with an associated retaining means formed by the edge 40a of the groove 40 to provide axial retention of the fastening screw 20 relatively 25 to the spacer 18. Indeed, 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 40a 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 40a. The edge 40a forms an abutment surface for the protuberance 54. To allow the insertion screw 20 to be inserted into the bore 18 of the spacer, the protuberance 54 is shaped so as to be able to pass through. of the notch 42. In this purpose, the circumferential dimension of the protuberance 54 is strictly smaller than that of the notch 42. As illustrated more clearly in FIG. 5, the protuberance 54 is delimited in the circumferential direction by two opposite side edges 54a, 54b. The radial dimension of the protuberance 54 is also strictly smaller than that of the notch 42. In order to mount the fixing screw 20, the operator axially introduces said screw into the bore 18b and aligns the protuberance 54. and the notch 42 so as to pass the protrusion 54 through the notch 42. The screw 20 is pushed axially to bring the washer 42 axially bearing against the bearing 14. The protuberance 54 is then located The operator then pivots the screw 20 relative to the spacer 18 so as to shift the protuberance 54 in the circumferential direction relative to the notch 42 and prevent extraction of the screw. As indicated above, the cooperation between the protuberance 54 and the edge 40a of the groove 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 20 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, a single protrusion 54 is provided on the fixing screw. Alternatively, it is possible to provide several protuberances on the fixing screw. In this case, several opening notches specific to each protuberance are provided on the spacer. In the described embodiments, the introduction of the protrusion or protuberances of the fixing screw inside the annular groove 40 of the spacer is carried out by means of one or more notches opening on the front surface 18c. In a variant, as illustrated in FIG. 6, in which the identical elements bear the same references, the spacer 18 is 3038020 devoid of such notches. The introduction of the protrusion of the fixing screw inside the groove 40 is done here by force fitting. In this case, it may be preferable to slightly reduce the radial dimension of the protuberance so as to facilitate its mounting in the groove 40. In the previously described embodiments, the protuberance is integral with the screw. Alternatively, it is possible to provide, as illustrated in FIG. 7, in which the identical elements bear the same references, a fastening screw 20 comprising a protrusion 56 attached and fixed thereto by any appropriate means, for example by overmolding. , gluing, gluing, etc. The arrangement of the protuberance 56 on the screw 20 is identical to that described above for the protuberance integral with the screw. With such a protrusion 56 attached, it is advantageous to make it in a softer material than the material of the screw when the spacer is devoid of notch (s) opening (s) as provided in the second embodiment described. The protuberance 56 may for example be made of elastic synthetic material so as to facilitate its deformation upon the insertion of the screw 20 into the bore of the spacer. The protuberance 56 may for example be made of elastomer such as a nitrile rubber, or thermoplastic elastomer or polyurethane. Alternatively, it is possible to provide on the screw a plurality of protuberances 56 spaced relative to each other in the circumferential direction or a protuberance 56 of annular shape. In the exemplary embodiments illustrated, the groove 40 of the spacer does not open on any of the end surfaces 18c, 18d. As a variant, as illustrated in FIG. 8, in which the identical elements 30 have the same references, the groove 40 opens out on the front surface 18c of the spacer. The spacer 18 comprises a retaining ring 60 fixed in the groove 40 of the spacer. In the example shown, the retaining ring 60 is flush with the front surface 18c. Alternatively, the ring 60 could be slightly recessed with respect to said front surface. The ring 60 is adapted to cooperate with the protrusion 54 of the fixing screw to ensure the axial retention of said screw relative to the spacer 18. More specifically, the lateral edge of the retaining ring which is oriented on the side protrusion 54 cooperates with it. The ring 60 extends projecting from the bottom 40c of the groove. In this embodiment, the retaining means formed by the ring 60 integral with the spacer 18 is attached to it, unlike the previous embodiments in which the retaining means is made integral with said spacer. The retaining ring 60 attached to the spacer 18 may be open in the circumferential direction so as to delimit an axially open notch on the side of the front surface 18c. Alternatively, the retaining ring 60 can be continuous in the circumferential direction.

In the exemplary embodiments 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 a portion 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. The invention has been illustrated on the basis of a pulley device comprising a rolling bearing provided with an inner ring, an outer ring and at least one row of rolling elements arranged between the rings. Alternatively, the bearing may be of the sliding type and consist of an annular body, for example made of thermoplastic material, and may comprise radial grooves capable of being filled with lubricant. In another variant, the sliding bearing may comprise two tracks or rings sliding directly on one another.

Claims (10)

REVENDICATIONS1. A pulley device for a tensioning roller or belt or chain winder comprising a pulley (12), a bearing (14), a spacer (18) supporting said bearing and provided with a through bore (18b) and two end surfaces ( 18c, 18d) axially delimiting said bore, and a fixing screw (20) comprising a rod (46) extending inside said bore and a head (44), characterized in that the spacer comprises a groove ( 40) extending radially from the bore (18b) and arranged axially recessed with respect to the front surface (18d) located axially opposite the head (44) of the fastening screw, said screw comprising at least a first retaining means (54; 56) integral with said rod (46) and projecting into the groove (40), the spacer including at least one second retaining means (40a); 60) secured to said spacer, projecting from a bottom (40c) of the groove and adapted to cooperate by contact with said first retaining means (54; 56) to ensure the axial retention of the fixing screw relative to the spacer. 2. Device according to claim 1, wherein at least said front surface (18d) of the spacer located axially opposite the head (44) of the fixing screw is smooth. 3. Device according to claim 1 or 2, wherein the annular groove (40) of the spacer is defined axially by two lateral edges (40a, 40b) opposite, the lateral edge (40a) arranged axially on the side of the head. (44) of the fastening screw forming the second retaining means. 4. Device according to claim 1 or 2, wherein the spacer comprises a retaining ring (60) mounted in the groove and forming the second retaining means. 5. Device according to any one of the preceding claims, wherein the annular groove (40) of the spacer is disposed axially recessed relative to the front surface (18c) located axially on the side of the head (44) of the screw. 3038020 13 6. Device according to any one of the preceding claims, wherein the spacer further comprises at least one notch (42) open axially on the side of the end surface (18c) which is situated axially on the side of the head (44). the fixing screw, said notch being open into the groove (40) and being delimited in the circumferential direction by two opposite lateral edges (42a, 42b). 7. Device according to claim 6, wherein said first retaining means (54; 56) of the fixing screw is shaped so as to be able to pass through said notch when said screw is inserted into the bore (18b). . 8. A device according to any one of the preceding claims, wherein the shank (46) of the fixing screw comprises a smooth portion (48) located axially on the side of the head and a threaded portion (50), said first means retainer (54; 56) being disposed on the smooth portion. 9. Device according to any one of the preceding claims, wherein said first retaining means (54) of the fastening screw is integrally formed with said screw. 20 10.Device according to any one of claims 1 to 8, wherein said first retaining means (56) of the fixing screw is attached to said screw, for example by overmolding, said first retaining means being made of a material more flexible than the material of the screw.