Pulley units for tensioning or winding rollers

Abstract

The invention relates to a pulley device (1) for a tensioning roller or a winding roller of a transmission element, the pulley device (1) comprising a pulley (2) and a bearing (3). The bearing is provided with a rotating outer ring (6) on which the pulley (2) is mounted, a fixed inner ring (5) and at least one row of rolling elements (7, 8) arranged between the inner ring (5) and the outer ring (6). The inner ring (5) of the bearing (3) comprises at least one end (33, 34) protruding in the axial direction relative to the outer ring (6). The pulley (2) is provided with at least one pulley element (21, 22) having a C-shaped axial cross section. One pulley element (21, 22) is provided with a lateral portion (35, 37) which extends substantially in the radial direction to enter the immediate vicinity of the outer surface of the end (33, 34) of the inner ring (5) protruding in the axial direction.

Description

Technical Field

[0001] The invention relates to the field of pulley arrangements for tensioning or winding rollers for cooperating with a transmission element, for example a timing belt or timing chain or a drive belt or drive chain of an internal combustion engine of a motor vehicle. Background Art

[0002] Such rollers are usually used to keep the tension in the transmission element permanently within a given range or to locally change the path taken by the transmission element. Therefore, the rollers are called tensioning rollers and winding rollers, respectively. In the winding roller, the pulley is rotatably mounted on a threaded body via a bearing, and the roller is then fixed directly or indirectly to the engine block or to an element of the tensioning roller device, such as an articulated arm or an eccentric.

[0003] The bearing generally comprises a fixed inner ring having holes through which screws pass, a rotating outer ring on which a pulley is mounted (surmounted), and at least one row of rolling elements between the inner and outer rings.

[0004] Such devices are often equipped with seals or additional ( / attached) protective flanges that help protect the device from contaminants or splashes originating from the external environment.

[0005] However, particles or other contamination elements may enter into the immediate vicinity of the sealing components of the bearing and may accumulate in the immediate vicinity of the sealing components of the bearing over time. Since the sealing components may wear, the risk of contamination entering the bearing cavity increases with the service life of the pulley arrangement. Such internal contamination may lead to an accelerated degradation of the internal components of the bearing, in particular to an accelerated degradation of the contact surfaces between the rolling elements and the rings. This may lead to a reduction in the quality of the rotating mechanical connection provided by the pulley arrangement and to a reduced service life of the internal components of the pulley arrangement. In particular in operating mode, the risk of breakage is also higher. Summary of the invention

[0006] The present invention aims to remedy these disadvantages.

[0007] More particularly, the present invention aims to provide such a pulley arrangement which is resistant to high levels of contamination, is particularly economical and can be easily and safely installed, forming a subassembly which cannot be dismantled and which requires little axial and radial space.

[0008] The invention relates to a pulley device for a tensioning roller or a winding roller of a transmission element, the pulley device comprising a pulley and a bearing.

[0009] The bearing is provided with a rotating outer ring, the rotating outer ring having an outer surface, a hole with at least one outer raceway, a front lateral surface and a rear lateral surface. The bearing is also provided with a fixed inner ring, the fixed inner ring having a hole capable of receiving the body of a screw, an outer surface with at least one inner raceway, a rear lateral surface for bearing against a support for a pulley device and a front lateral surface capable of bearing against the head of the screw, the inner ring and the outer ring being coaxial and forming a radial space between each other. The bearing is provided with at least one row of rolling elements, the at least one row of rolling elements being arranged in the radial space and located between the inner raceway and the outer raceway.

[0010] The pulley is provided with at least one pulley element, the at least one pulley element having a C-shaped axial cross-section and having an inner part, an outer part and a middle part, the inner part being mounted on the outer surface of the outer ring of the bearing, the outer part having an outer surface for cooperating with the transmission element, the middle part extending substantially radially between an axial end of the inner part along a first axial side and an axial end of the outer part along the first axial side, the pulley element being formed in one piece.

[0011] According to the invention, the inner ring of the bearing comprises at least one end protruding axially relative to the lateral surface of the outer ring. At least one pulley element is also provided with a lateral portion extending substantially radially from the axial end of the inner portion on the axially opposite side of the middle portion, the free end of the lateral portion entering in the immediate vicinity of the outer surface of the axially protruding end of the inner ring.

[0012] Further advantageous but not essential features of the invention according to which they are used alone or in combination:

[0013] - The inner ring of the bearing is in one piece.

[0014] -The inner ring of the bearing comprises a track element provided with an outer surface having at least one inner raceway for rolling elements, and a spacer provided with an outer surface mounted in a hole in the track element for receiving a screw, a rear lateral surface for bearing against a support for a pulley arrangement, and a front lateral surface for bearing against the head of the screw.

[0015] - The pulley arrangement comprises a retaining member for cooperating with the screw.

[0016] The bore of the fixed inner ring comprises an inner circumferential groove in which is housed an annular O-ring cooperating with the screw.

[0017] - The cage maintains the circumferential spacing of the rolling elements.

[0018] - The rolling elements are balls.

[0019] - The inner part of the pulley element is tightly ( / securely) mounted on the outer surface of the outer ring of the bearing.

[0020] A lateral portion of a pulley element bears axially against a lateral surface of the outer ring of the bearing.

[0021] The free ends of the lateral portions of the pulley element enter into the immediate vicinity of the outer surface of the end portion of the inner ring protruding in the axial direction, so as to form a narrow channel.

[0022] The free end of the lateral portion of the pulley element is provided with a sealing member having at least one sealing lip in sliding contact with the outer surface of the axially protruding end of the inner ring.

[0023] - The sealing member is made of a polymer material.

[0024] - The sealing member is overmoulded on the free end of the lateral portion of the pulley element.

[0025] - The end of the inner ring protrudes axially relative to the lateral portion of the pulley element.

[0026] - The ends of the inner ring are chamfered.

[0027] - A washer is interposed between the front lateral surface of the inner ring and the head of the screw.

[0028] The outer diameter of the washer is strictly greater than the inner diameter of the free end of the lateral portion of the pulley element.

[0029] - The washer is formed as a single piece with the head of the screw.

[0030] - said end of said inner ring is provided with a circumferential groove on its outer surface.

[0031] - The pulley comprises a pulley element having a C-shaped axial cross section.

[0032] - The pulley comprises two pulley elements having a C-shaped axial section.

[0033] The middle parts of the two pulley elements bear axially against each other.

[0034] The pulley element is made of metal, for example steel.

[0035] The pulley element is made of a plastic material, for example polyamide. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The invention will be better understood on reading the detailed description of embodiments given purely by way of non-limiting examples and illustrated in the accompanying drawings, in which:

[0037] - Figure 1 is a rear perspective view of a pulley device according to a first embodiment of the present invention;

[0038] - Figure 2 yes Figure 1 An axial cross-sectional view of the pulley device in FIG.

[0039] - Figure 3 is an axial cross-sectional view of a pulley device according to a second embodiment of the present invention; and

[0040] - Figure 4 1 is an axial cross-sectional view of a pulley device according to a third embodiment of the present invention. DETAILED DESCRIPTION

[0041] As in Figure 1 and Figure 2 As can be seen in the drawing, the pulley device (with the overall reference 1) for a tensioning roller or winding roller for a belt has a geometric axis X1 and comprises a pulley 2 designed to cooperate with a transmission element (not shown) such as a belt or chain, a bearing 3 and a screw 4.

[0042] The bearing 3 comprises a fixed inner ring 5 and a rotating outer ring 6, the inner ring 5 and the outer ring 6 being coaxial with respect to the axis X1. The bearing 3 also comprises two rows of rolling elements 7 and 8, which are arranged in the form of balls in the radial space formed between the two rings, and a cage (not shown), which respectively maintains the circumferential spacing of the rolling elements 7 and 8.

[0043] The inner ring 5 and the outer ring 6 are coaxial. In the exemplary embodiment shown, the ring is solid, that is to say it is obtained by machining or grinding with material removed from a metal tube, a bar, a forged part or a rolled blank.

[0044] The inner ring 5 comprises a bore 9 , a stepped outer surface 10 provided with a raceway (not shown) having an axial section with a concave annular inner profile adapted for the rolling elements 7 , 8 , and rear and front lateral surfaces 11 , 12 .

[0045] The outer ring 6 includes a stepped cylindrical hole 13, an outer cylindrical surface 14, a rear lateral surface 15 and a front lateral surface 16. The stepped cylindrical hole 19 is provided with a raceway (not shown), the axial cross-section of which has a concave annular inner contour suitable for the rolling elements 7 and 8, and the pulley 2 is mounted on the outer cylindrical surface 14.

[0046] The fixed inner ring 5 extends axially beyond the rotating outer ring 6 in an axially rearward direction towards the support on which the pulley device 1 is mounted. Therefore, the fixed inner ring 5 is provided with an axial end 33 protruding rearwards, the rear lateral surface 11 of which is axially offset relative to the rear lateral surface 15 of the outer ring 6. The rear lateral surface 11 serves to form a bearing surface for the bearing 3 against the support for the device 1.

[0047] The fixed inner ring 5 also extends axially beyond the rotating outer ring 6 in an axial forward direction away from the support on which the pulley arrangement 1 is mounted. Therefore, the fixed inner ring 5 is provided with a forwardly projecting axial end 34, the front lateral surface 12 of which is axially offset relative to the front lateral surface 16 of the outer ring 6. The front lateral surface 12 serves to form a bearing surface for the screw 4.

[0048] Advantageously, the bearing 3 comprises an annular seal (not indicated) on each axial side to close the radial space situated between the rings 5 ​​, 6 and housing the rolling elements 7 , 8 inside it.

[0049] As an option, the bearing may include a different number of rows of rolling elements arranged between the outer ring and the inner ring, such as a single row of rolling elements.

[0050] As an option, the bearing may include other types of rolling elements, such as tapered rollers or needle rollers.As an option, the bearing may be a plain bearing.

[0051] In this embodiment, the inner ring 5 is formed in one piece. According to an alternative embodiment not shown, the bearing 3 may comprise an annular spacer mounted in the inner ring 5 .

[0052] The screw 4 comprises a body 17 and a head 18 at one axial end of said body 17. The body 17 is housed in the bore 9 of the bearing 3 and extends axially beyond the rear lateral surface 11 of the fixed inner ring 5. The body 17 comprises a threaded portion intended to be screwed into a corresponding threaded opening of a support for the pulley device 1. On the axially opposite side of the support into which the body 17 is intended to be screwed, the head 18 of the screw 4 has a relatively flat surface that bears against the front lateral surface 12 of the inner ring 5 of the bearing 3.

[0053] In the embodiment shown, the bore 9 of the inner ring 3 is provided at its rear end with a circumferential groove 19. An annular O-ring 20, preferably an elastic annular O-ring, is housed in said groove 19 and cooperates with the body 17 of the screw 4 to keep the screw 4 fixed to the inner ring 5 and thus to the pulley device 1.

[0054] The pulley 2 comprises a rear pulley element 21 and a front pulley element 22 .

[0055] The rear pulley element 21 comprises an outer annular portion 23 having a cylindrical hole (not indicated) and an outer cylindrical surface 24 capable of cooperating with a transmission member. The element 21 also comprises an inner annular portion 25 having an outer cylindrical surface (not indicated) and a cylindrical hole 26 tightly mounted on the outer cylindrical surface 14 of the rotating outer ring 6 of the bearing 3. The outer annular portion 23 is tubular and has a larger diameter than the inner annular portion 25, which is also tubular and radially surrounds the inner annular portion 25. The axial dimension of the outer annular portion 23 is also larger than that of the inner annular portion 25, which protrudes axially relative to the inner annular portion 25 on the rear axial side of the device 1.

[0056] Finally, the rear pulley element 21 comprises an intermediate portion 27 connecting the inner annular portion 25 and the outer annular portion 23. The intermediate portion 27 extends radially between the front axial ends of the inner annular portion 25 and the outer annular portion 23 of the rear pulley element 21.

[0057] The rear pulley element 21 has an overall shape that is C-shaped in axial section and defines an annular opening open at the rear axial side of the device 1 towards a support on which the device 1 is mounted.

[0058] The front pulley element 22 comprises an outer annular portion 28 having a cylindrical hole (not indicated) and an outer cylindrical surface 29 capable of cooperating with a transmission member. The element 22 also comprises an inner annular portion 30 having an outer cylindrical surface (not indicated) and a cylindrical hole 31 tightly mounted on the outer cylindrical surface 14 of the rotating outer ring 6 of the bearing 3. The outer annular portion 28 is tubular and has a larger diameter than the inner annular portion 30, which is also tubular and radially surrounds the inner annular portion 30. The axial dimension of the outer annular portion 28 is also larger than that of the inner annular portion 30, the outer annular portion 28 protruding axially relative to the inner annular portion 30 at the front axial side of the device 1.

[0059] Finally, the front pulley element 22 comprises an intermediate portion 32 connecting the inner annular portion 30 and the outer annular portion 28. The intermediate portion 32 extends radially between the rear axial ends of the inner annular portion 30 and the outer annular portion 28 of the front pulley element 22.

[0060] The front pulley element 22 has an overall shape that is C-shaped in axial section and defines an annular opening that is open at the front axial side of the device 1 , facing away from the support on which the device 1 is mounted.

[0061] The rear pulley element 21 and the front pulley element 22 are mounted on the rotating outer ring 6 of the bearing 3 so that their middle parts 27 and 32 bear against each other in the axial direction. The pulley elements 21, 22 are mounted in a symmetrical manner in the axial direction. The outer cylindrical surface 24 of the outer annular part 23 of the rear pulley element 21 and the outer cylindrical surface 29 of the outer annular part 28 of the front pulley element 22 respectively form in combination a surface for cooperating with a transmission element.

[0062] Advantageously, each of the rear pulley element 21 and the front pulley element 22 is in one piece and is advantageously formed by cutting and stamping a metal sheet, for example made of steel.

[0063] According to the invention, the rear pulley element 21 is provided with a rear lateral portion 35 .

[0064] The rear lateral portion 35 extends substantially radially from the axial end of the inner portion (inner annular portion) 25 on the axially opposite side of the middle portion 27 of the rear pulley element 21. The rear lateral portion 35 bears axially against the rear lateral surface 15 of the outer ring 6 of the bearing 3. The rear lateral surface 35 is provided with a free end which enters into the immediate vicinity of the outer surface of the axially rearwardly protruding end portion 33 of the inner ring 5 to form a radial narrow channel 36.

[0065] Similarly, on the axially opposite side of the rear lateral portion 35, the front pulley element 22 is provided with a front lateral portion 37. The front lateral portion 37 extends substantially radially from the axial end of the inner portion (inner annular portion) 30 on the axially opposite side of the middle portion 32 of the front pulley element 22. The front lateral portion 37 bears axially against the front lateral surface 16 of the outer ring 6 of the bearing 3. The front lateral surface 37 is provided with a free end, which enters into the immediate vicinity of the outer surface of the axially forwardly protruding end 34 of the inner ring 5 to form a radial narrow channel 38.

[0066] Particularly advantageously, the axially forwardly projecting end 34 of the inner ring 5 projects axially relative to the front lateral portion 37 of the front pulley element 22. Furthermore, the axially forwardly projecting end 34 is chamfered to form an additional barrier to the intrusion of contaminants and water. In an alternative manner not shown, the outer surface of the axially forwardly projecting end 34 can be provided with a circumferential groove to form not only a barrier to contaminants and water, but also a collector for contaminants and water. Such a component can also be provided on the rear surface of the inner ring 5.

[0067] In an alternative not shown, one of the front pulley element 21 and the rear pulley element 22 may be provided with a lateral portion.

[0068] Figure 3 A second embodiment of the invention is shown, wherein identical elements are provided with identical reference numerals.

[0069] In this embodiment, an annular washer 39 is interposed axially between the front lateral surface 12 of the inner ring and the head 18 of the screw 4. The washer 39 has a central hole in which the body 17 of the screw 4 is housed.

[0070] The front lateral surface 12 is arranged at the axially forwardly projecting end 34 of the inner ring 5. Thus, the washer 39 is axially offset relative to the front lateral portion 37 of the front pulley element 22.

[0071] Particularly advantageously, the outer diameter of the washer 39 is strictly greater than the inner diameter of the free end of the front lateral portion 37 .

[0072] Advantageously, the gasket 39 forms an additional barrier for preventing the intrusion of contaminants or water through the front narrow channel 38 between the front lateral portion 37 of the front pulley element 22 and the inner ring 5 .

[0073] Furthermore, advantageously, an axial narrow channel 40 may be formed between the gasket 39 and the lateral portion 37. The continuous structure of the axial narrow channel 40 and the radial narrow channels 38 forms a labyrinth seal for the device 1.

[0074] exist Figure 3 In the embodiment shown in , the washer 39 and the head 18 of the screw 4 are separate elements. In an alternative not shown, the washer and the head of the screw are formed as a single piece.

[0075] Figure 4 A third embodiment of the invention is shown in FIG. 2 , wherein identical elements are provided with identical reference numerals.

[0076] The free end of the rear lateral portion 35 of the rear pulley element 21 is provided with a sealing member 41 having a lip in sliding contact with the outer surface of the axially rearwardly protruding end portion 33 .

[0077] Similarly, the free end of the front lateral portion 37 of the front pulley element 22 is provided with a sealing member 42 having a lip in sliding contact with the outer surface of the axially forwardly projecting end portion 34 .

[0078] Advantageously, the sealing members 41, 42 are made of a polymer material.Preferably, the sealing members 41, 42 are overmoulded onto the free ends of the rear lateral portion 35 and the front lateral portion 37, respectively.

[0079] With such an embodiment, if application conditions permit, sealing components inside the bearing can be eliminated.

[0080] Embodiments of the invention have been shown as having a two-part pulley. As an alternative, the pulley arrangement can be provided with a single C-shaped pulley element. In this case, only one lateral part is provided on one axial side of the arrangement.

[0081] Furthermore, all or only some of the technical features of the various embodiments may be combined with each other. Thus, the pulley device may be adjusted in terms of cost, performance, and ease of use.

Claims

1. A pulley device (1) for use as a tensioning roller or a winding roller for a transmission element, the pulley device (1) comprising a bearing (3) and a pulley (2), - the bearing (3) is provided with a rotating outer ring (6), a fixed inner ring (5) and at least one row of rolling elements (7, 8), the rotating outer ring (6) having an outer surface (14), a hole (13) having at least one outer raceway, a front lateral surface (16) and a rear lateral surface (15), the fixed inner ring (5) having a hole (9) capable of receiving a body (17) of a screw (4), an outer surface (10) having at least one inner raceway, a rear lateral surface (11) for bearing against a support member for the pulley device and a front lateral surface (12) capable of bearing against a head (18) of the screw (4), the inner ring (5) and the outer ring (6) being coaxial and forming a radial space between each other, the at least one row of rolling elements (7, 8) being arranged in the radial space and being located between the inner raceway and the outer raceway; - the pulley (2) is provided with at least one pulley element (21, 22), the at least one pulley element (21, 22) having a C-shaped axial cross section and having an inner part (25, 30), an outer part (23, 28) and an intermediate part (27, 32), the inner part (25, 30) being mounted on the outer surface (14) of the outer ring (6) of the bearing (3), the outer part (23, 28) having an outer surface (24, 29) for cooperating with the transmission element, the intermediate part (27, 32) extending substantially in the radial direction between an axial end of the inner part (25, 30) along a first axial side and an axial end of the outer part (23, 28) along the first axial side, the pulley element (21, 22) being formed as a single piece; It is characterized in that The inner ring (5) of the bearing (3) comprises at least one end (33, 34) protruding in the axial direction relative to the lateral surface (15, 16) of the outer ring (6), At least one pulley element (21, 22) is further provided with a lateral portion (35, 37) extending substantially radially from an axial end of the inner portion (25, 30) on axially opposite sides of the intermediate portion (27, 32), the free end of the lateral portion (35, 37) entering in the immediate vicinity of the outer surface of the axially protruding end portion (33, 34) of the inner ring (5); The free ends of the lateral portions (35, 37) of the pulley elements (21, 22) are provided with sealing components (41, 42), and the sealing components (41, 42) have at least one sealing lip that is in sliding contact with the outer surface of the axially protruding end portions (33, 34) of the inner ring (5).

2. The pulley device according to claim 1, characterized in that: A lateral portion (35, 37) of a pulley element (21, 22) bears axially against a lateral surface (15, 16) of an outer ring (6) of the bearing (3).

3. A pulley arrangement according to any one of the preceding claims, characterised in that The free ends of the lateral portions (35, 37) of the pulley elements (21, 22) enter into the immediate vicinity of the outer surface of the axially protruding ends (33, 34) of the inner ring (5) to form narrow channels (36, 38).

4. The pulley device according to claim 1 or 2, characterized in that: The ends (33, 34) of the inner ring (5) protrude axially relative to the lateral portions (35, 37) of the pulley elements (21, 22).

5. The pulley device according to claim 1 or 2, characterized in that: The ends (33, 34) of the inner ring (5) are chamfered.

6. The pulley device according to claim 1 or 2, characterized in that: A washer (39) is interposed between the front lateral surface (12) of the inner ring (5) and the head (18) of the screw (4).

7. The pulley device according to claim 6, characterized in that The outer diameter of the washer (39) is strictly greater than the inner diameter of the free end of the lateral portion (37) of the pulley element (22).

8. The pulley device according to claim 1 or 2, characterized in that: The pulley (2) comprises two pulley elements (21, 22) with C-shaped axial cross-sections, and the middle parts (27, 32) of the two pulley elements (21, 22) are supported against each other in the axial direction.

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