FR3038955A1 - PULLEY DEVICE FOR TENDER ROLLER OR ROLLER AND ASSOCIATED MOUNTING METHOD - Google Patents

Abstract

The pulley device for a tensioning roller or belt or belt winder comprises a pulley 12, a mounting body 18 supporting the pulley and provided with a through bore 18b, and a fastening screw 20 extending inside said bore. The device further comprises at least one locking pin 22 mounted in an axial groove 50 of the mounting body which extends from the front surface 18d located axially opposite a head 44 of the fixing screw. . Said locking pin 22 is made at least partly of deformable material and cooperates by contact with the fixing screw to ensure the axial retention of said screw relative to the mounting body.

Description

Pulley device for tensioner roller or winder and associated mounting method

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 to further provide a relatively large annular groove 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. Moreover, this solution requires the use of a screw of particular design.

The present invention aims to remedy these disadvantages.

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 roller or belt or belt winder comprises a pulley, a mounting body supporting the pulley and provided with a through bore and two end surfaces axially defining said bore, and a fixing screw comprising a rod extending inside said bore and a head. The device further comprises at least one locking pin mounted in an axial groove of the mounting body which extends from the front surface located axially opposite the head of the fixing screw and which opens into said bore . Said locking pin is made at least partially of deformable material and cooperates by contact with the fixing screw to ensure the axial retention of said 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 which requires to provide an annular groove on the front surface of the body 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. On this front surface, the area adjacent to the bore is interrupted in the circumferential direction by the groove. The groove is formed locally on the front surface of the spacer, i.e. the groove is non-annular.

Moreover, the use of such a locking pin to ensure this axial retention is applicable to any type of screw design, for example with or without a groove. Blocking the fixing screw by axial and / or radial contact with the locking pin is obtained by deformation of said pin. The deformable nature of the locking pin also facilitates assembly of the device.

In one embodiment, said locking pin may be made at least partly of elastically deformable material.

Advantageously, said locking pin extends along an axis of elongation parallel to the axis of the fixing screw.

Preferably, the fixing screw comprises a rod extending inside said bore, said locking pin cooperating by contact with said rod. Said locking pin can cooperate by contact with a smooth portion of said rod. Alternatively, said locking pin can cooperate by contact with a threaded portion of said rod.

It may be advantageous to have a portion of said blocking pin axially between two successive flanks of the thread of the threaded portion and which cooperates by axial contact with said thread. The locking pin may comprise at least one inwardly projecting tongue forming said portion. Alternatively, it is possible to provide a protuberance formed in the form of a point extending radially inwardly to form said portion.

Alternatively or in combination, said locking pin cooperates by radial contact with the fixing screw to ensure axial retention by radial clamping on said screw.

The groove of the mounting body may be delimited radially by an axial bottom wall against which radially bears against said locking pin. The groove can lead to a front surface of the mounting body located axially opposite a head of the fixing screw.

In one embodiment, the device comprises a spacer forming the mounting body and a bearing radially interposed between said spacer and the pulley. In another mode, the device may be devoid of the spacer, a bearing ring then forming said mounting body. The invention further relates to a method of assembling a pulley device for a tensioning roller or belt or chain winder, in which a subassembly comprising a pulley and a mounting body provided with a through bore is mounted. then a fixing screw is inserted inside said bore of the mounting body. An axial groove of the mounting body is formed which is formed locally from a front surface of the spacer, before or after the step of introducing the fixing screw, at least one locking pin made at least partially deformable material for axially locking said screw relative to said contact mounting body.

The present invention will be better understood on studying the detailed description of embodiments taken as non-limiting examples and illustrated by the appended drawings, in which: FIG. 1 is an axial sectional view of a device pulley according to a first exemplary embodiment, - Figure 2 is a detail view of Figure 1, - Figure 3 is a perspective view of the device of Figure 1, - Figure 4 is a partial front view of the FIG. 5 is an axial sectional view of a pulley device according to a second exemplary embodiment.

In FIG. 1, the pulley device for tensioning roller 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 later, the device 10 also comprises a locking pin 22 to ensure the axial retention of the fixing screw 20 relative to the spacer 18 .

The pulley 12 comprises an outer axial portion 24 having an outer surface intended to cooperate with a belt or a 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 of 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 to inside which are housed the rolling elements 34 and the cage 36. In the illustrated embodiment, the inner and outer 30 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 parts. 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 protruding relative to the pulley 12. The spacer 18 comprises an axial cylindrical outer surface 18a, a cylindrical bore 18b, of axis 16, and two opposite radial face 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. One of the front 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 illustrated embodiment, the front surface of the inner ring, located axially opposite the shoulder 38, is slightly protruding from the front surface 18c of the spacer. The spacer 18 leaves this radial surface 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 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.

The fastening screw, with axis 16, 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 intended to be inserted into a threaded hole formed in the support outside the device.

The fastening 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 18. Alternatively, it may 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.

As indicated above, the blocking pin 22 makes it possible to axially lock the fixing screw 20 with respect to the spacer 18. The locking pin 22 is distinct from the screw 20 and the spacer 18. The locking pin 22 is mounted in an axial groove 50 formed on the spacer. In this embodiment, no fixing of the locking pin 22 on the spacer 18 is provided. Alternatively, the locking pin 22 could be fixed on the spacer 18 by any suitable means, for example by gluing or overmolding.

The locking pin 22 is made of a deformable material, for example a synthetic material such as a polyamide 6.6, or an elastomer or a rubber or an elastomeric thermoplastic. The locking pin 22 is preferably made of elastic deformable material. The blocking pin 22 is made in one piece. The blocking pin 22 may be obtained by molding. The locking pin 22 extends along an axis of elongation parallel to the axis 16. The locking pin 22 comprises a body 22a and a retaining tongue 22b extending inwards from said body and co-operating with the fastening screw 20 to ensure its axial retention as will be described in more detail later.

The groove 50 of the spacer is formed locally on the front surface 18d so as to leave circumferentially on either side of said groove an area of material adjacent to the bore 18b. The groove 50 extends axially from the front surface 18d and opens radially into the bore 18b. The groove extends along an axis parallel to the axis 16. The groove 50 is delimited axially by a radial shoulder 50a. The groove 50 extends axially between the front surface 18d and the shoulder 50a. The shoulder 50a extends radially outwardly the bore 18b. The groove 50 is delimited radially by a bottom wall 50b axial opening on the front surface 18d. The bottom wall 50b extends the shoulder 50a axially outwards. With the exception of the groove 50, the radial surface 18d of the spacer is smooth. The term "smooth" means a face devoid of projections, pins, asperities, ribs, etc. or grooves or recesses, etc. This design makes it possible to increase the contact zone between this frontal surface of the spacer and the support associated with the device 10.

As shown more clearly in Figures 3 and 4, the groove 50 of the spacer is delimited in the circumferential direction by two opposite edges 50c, 50d side opposite. The groove 50 extends over an angular sector strictly less than 360 °. In the exemplary embodiment illustrated, the groove 50 extends over an angular sector between 40 ° and 50 °. The groove 50 can be obtained by countersinking. In the exemplary embodiment illustrated, the section of the groove 50 is rectangular. Alternatively, the axial section of the groove 50 may have other shapes, for example square, trapezoidal, circular, etc.

The body 22a of the locking pin bears in the circumferential direction against the edges 50c, 50d of the groove, and in the radial direction against the bottom wall 50b of said groove. The body 22a is in register with the groove 50. The body 22a is located axially recessed relative to the front surface 18d of the spacer. In this embodiment, the body 22a also remains radially recessed from the fixing screw 20.

As illustrated more clearly in FIG. 2, the tab 22b of the locking pin extends obliquely inwardly from the body 22a. The tongue 22b extends from a small diameter edge of the bore body 22a. The tongue 22b extends inwardly projecting relative to the bore 18b of the spacer. The tongue 22b is mounted in contact against the threaded portion 46 of the fixing screw. The tongue 22b engages between two successive flanks facing the thread of the threaded portion 46.

An axial displacement of the screw 20 relative to the spacer 18 is blocked by the axial contact between the tongue 22b of the flocking pin and the thread of the threaded portion 46 of said screw. In this embodiment, the axial locking is achieved by interference between the threaded portion 46 of the screw and the tongue 22b. The tongue 22b forms a retaining means cooperating by axial contact with the threaded portion 46 of the fixing screw. The tongue 22b may be shaped to be in conformance with the flanks of the threaded portion 46 of the screw with which it cooperates.

To assemble the pulley device, the procedure is as follows. In a first step, a subassembly is fitted provided with the pulley 12, the rolling bearing 14, the spacer 18 on which the groove 50 has previously been formed locally, and the locking pin 22. Locking pin 22 on the spacer is effected by simple axial thrust.

Then, in a second step, the fastening screw 20 equipped with the washer 48 is introduced into the bore 18b of the spacer to bring said washer axially into contact with the inner ring 30 of the bearing. When the fastening screw 20 is inserted, the tongue 22b is deformed and flexes radially outwards under the effect of contact with said screw.

The cooperation in the axial direction between the tongue 22b of the locking pin and the threaded portion 46 serves to block any axial displacement of the screw 20 relative to the spacer 18 in the direction opposite to the insertion direction of the screw. The tongue 22b makes it possible, by a bracing effect, to promote the axial retention of the screw 20. The deformable nature of the locking pin 22 also makes it easier to introduce the fixing screw 20 into the interior of the housing. the bore 18b of the spacer. Alternatively, in an assembly variant, it is possible to insert the locking pin 22 inside the groove 50 of the spacer after the step of introducing the fixing screw 20. The exemplary embodiment illustrated in FIG. 5, in which the identical elements bear the same references, differs from the preceding example in that the locking pin 22 does not have a retaining tab. The body 22a of the pin comes here radially in contact against the threaded portion 46 of the fixing screw. In this embodiment, the axial retention of the fixing screw 20 relative to the spacer is effected by radial clamping of the locking pin 22 on said screw. Given the deformable nature of the locking pin 22, portions of the body 22a of the pin can engage between successive flanks opposite the thread of the threaded portion 46 of the screw and participate in the axial retention of the screw 20 by contact axial.

In this exemplary embodiment, the tightening torque to be exerted on the fastening screw 20 to fix the device 10 on the associated support is greater than that to be applied with the device 10 of the first exemplary embodiment to the extent that the entire the inner surface of the body 22a here comes into frictional contact against the threaded portion 46 of the screw.

In each of the exemplary embodiments illustrated, the locking pin 22 cooperates by contact with the threaded portion 46 of the fixing screw. Alternatively, it is possible to provide a cooperation of the locking pin 22 by contact with the smooth portion 44 of the fixing screw. However, it is favored to obtain a good axial locking of the fixing screw 20 in the case of a cooperation of the locking pin 22 with the threaded portion 46 of the screw.

In the exemplary embodiments illustrated, the head 44 of the fastening screw extends axially beyond the pulley 12. In a variant, it is possible to provide a clearance on the front surface 18c of the spacer so as to receive at least a 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 support washer.

In the embodiments described, the device comprises the spacer 18 which is interposed radially between the bearing 14 and the fixing screw 20. The locking pin 22 is housed in the axial groove 50 formed on the spacer. Alternatively, the device could be devoid of the spacer 18. In this case, the fixing screw 20 extends directly inside the bore of the inner ring of the bearing. The inner ring comprises the axial groove inside which the locking pin is mounted.

In the exemplary embodiments described, a single locking pin is provided. As a variant, it is possible to provide a plurality of locking pins for effecting the axial retention of the fixing screw.

In this case, several grooves specific to each locking pin are provided on the spacer or on the inner ring of the bearing. 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 comprise 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)

A pulley device for a tensioning roller or belt or chain winder comprising a pulley (12), a mounting body (18) supporting the pulley 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 device further comprises at least one counter blocking device (22) mounted in an axial groove (50) of the mounting body which extends from the end surface (18d) located axially opposite the head (44) of the fastening screw and which opens in said bore, said locking pin (22) being made at least partially of deformable material and cooperating by contact with the fixing screw to ensure the axial retention of said screw relative to the mounting body. 2. Device according to claim 1, wherein said locking pin (22) extends along an axis of elongation parallel to the axis (16) of the fixing screw. 3. Device according to claim 1 or 2, wherein the groove (50) of the mounting body is delimited radially by an axial bottom wall (50b) against which comes radially bearing said locking pin (22). 4. Device according to any one of the preceding claims, wherein the screw (20) for fixing comprises a rod (42) extending inside said bore (18b), said locking pin (22) cooperating with said rod. 5. Device according to claim 4, wherein said locking pin (22) cooperates with a threaded portion (46), or a smooth portion (44) of said rod. 6. Device according to claim 5, wherein at least a portion (22b; 22a) of said locking pin (22) is located axially between two successive flanks of the thread of the threaded portion (46) of said rod and cooperates by axial contact. with said thread. 7. Device according to any one of the preceding claims, wherein said locking pin (22) cooperates by radial contact with the fixing screw to ensure the axial retention by radial clamping on said screw. 8. Device according to any one of the preceding claims, wherein said groove (50) opens on a front surface (18d) of the mounting body located axially opposite a head (44) of the fixing screw. 9. Device according to any one of the preceding claims, wherein the device comprises a spacer (18) forming the mounting body and a bearing (14) radially interposed between said spacer and the pulley (12). 10. A method of assembling a pulley device for a tensioner roller or belt or chain winder, in which a subassembly comprising a pulley and a mounting body provided with a through bore is mounted, then a fastening screw comprising a head and a rod within said bore of the mounting body, characterized in that is mounted in an axial groove of the mounting body formed locally from a front surface of the spacer, before or after the step of introducing the fixing screw, at least one locking pin made at least partly of deformable material for axially locking said screw relative to said contact mounting body.