Pulley device for a tensioning roller or a winding roller

Abstract

The present 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); a rolling bearing (3) provided with a rotating outer ring (7), a fixed inner ring (6) and at least one row of rolling elements (9, 10), the pulley (2) being mounted on an outer surface (22) of the outer ring (7), the inner ring (6) and the outer ring (7) being coaxial, a radial space (8) being formed between the inner ring (6) and the outer ring (7), and the at least one row of rolling elements (9, 10) being arranged in the radial space (8). The pulley device (1) further comprises at least one annular protective flange (4, 5) having a substantially radial body. The flange (4, 5) is fixed to the rotating outer ring (7) by pressing an axially protruding portion (29, 30) of the pulley (2) against an outer edge of the flange (4, 5).

Description

Field of the Invention

[0001] The present invention relates to the field of pulley devices for tensioning or winding rollers, which are arranged to cooperate with a transmission element, for example, with a belt or a distributor or a drive train of an internal combustion engine of a motor vehicle. Background Art

[0002] Such rollers are generally used to permanently maintain the tension on a transmission element within a defined range or to locally change the path taken by the transmission element. Thus, the corresponding terms tensioning roller or winding roller are used. In a winding roller, the pulley is mounted to rotate on a helix of a threaded body via a rolling bearing, and then the roller is directly or indirectly fixed to the engine block or to an element of a tensioning roller device, such as a hinged arm or an eccentric wheel.

[0003] A rolling bearing generally includes a fixed inner ring having a hole through which a screw passes, a rotating outer ring on which the pulley is placed, and at least one row of rolling elements interposed between the inner ring and the outer ring.

[0004] Such devices often come equipped with seals, and even additional protective flanges, which help protect the device from contamination or splashing from the external environment.

[0005] However, particulate matter or other contaminating elements may penetrate, which will accumulate over time at the location of the sealing components adjacent to the rolling bearing. Since the sealing components may wear, the risk of contaminants entering the bearing cavity increases with the service life of the pulley device. This internal contamination may lead to accelerated deterioration of the internal components of the rolling bearing, particularly may lead to accelerated deterioration of the contact surfaces between the rolling elements and the rings. Then, the result may be a reduction in the quality of the rotary mechanical linkage provided by the pulley device and a reduction in the service life of the internal components of the rolling bearing. In particular, during the operating mode, the risk of breakage is also relatively high. Summary of the Invention

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

[0007] More particularly, the present invention aims to provide such a pulley device that resists high contamination conditions, is particularly economical, easy and safe to install, and forms an inseparable sub-assembly and has a reduced axial and radial volume.

[0008] The present invention relates to a pulley device for a tensioning or winding roller of a transmission element, the pulley device including a pulley and a rolling bearing, the pulley having an outer surface for cooperating with the transmission element.

[0009] The rolling bearing is provided with a rotating outer ring, a fixed inner ring and at least one row of rolling elements. The pulley is mounted on the outer surface of the outer ring. The inner ring and the outer ring are coaxial, and a radial space is formed between the inner ring and the outer ring. The at least one row of rolling elements is arranged in the radial space.

[0010] The pulley device further includes at least one annular protective flange having a substantially radial body.

[0011] According to the invention, the pulley has at least one portion that axially projects relative to the lateral surface of the rotating outer ring, and the flange is mounted in a hole of the axially projecting portion. The flange is fixed to the rotating outer ring by crimping the axially projecting portion of the pulley toward the outer edge of the flange.

[0012] Thus, the outer edge of the flange is axially clamped between the crimped portion of the pulley and the rotating outer ring.

[0013] According to the invention, the annular protective flange is firmly mounted to the pulley device with sufficient concentricity, avoiding the design of complex components.

[0014] The pulley device (more particularly the radial space between the coaxial rings of the rolling bearing) prevents the entry of contamination. Thereby improving the life and quality of the mechanical linkage ensured by the rolling bearing.

[0015] According to other advantageous but non-essential features of the invention, such a pulley device may further include the following features used alone or in any technically permissible combination:

[0016] - The flange directly bears against the lateral surface of the outer ring.

[0017] - The axially projecting portion of the pulley is crimped at multiple positions on the outer periphery of the outer edge of the flange.

[0018] - The flange has an inner edge forming a hole, and the inner edge forming the hole enters a position adjacent to the outer surface of the fixed inner ring.

[0019] - The inner ring of the rolling bearing is made of a single piece.

[0020] - The inner ring of the rolling bearing includes a raceway element and a spacer. The raceway element is provided with an outer surface suitable for the rolling element, and the spacer is provided with an outer surface mounted in a hole of the raceway element.

[0021] - The cage ensures the circumferential spacing of the rolling elements.

[0022] - The rolling elements are balls.

[0023] - The pulley device further includes a rear sealing member and a front sealing member that enclose the radial space on each axial side.

[0024] - The pulley is made of metal, for example, made of steel.

[0025] - The pulley is made of a plastic material, for example, made of polyamide.

[0026] - The pulley is formed by overmolding a plastic material onto the outer ring of the rolling bearing.

[0027] - The flange is made of metal, for example, made of steel.

[0028] - The flange is made of a plastic material, for example, made of polyamide.

[0029] Brief Description of the Drawings

[0030] The present invention will be better understood by reading the following embodiments given entirely by way of non - limiting example.

[0031] A description is given with reference to the accompanying drawings, in which:

[0032] - Figure 1 is a perspective view of a pulley device according to an embodiment of the present invention;

[0033] - Figure 2 is Figure 1 the axial sectional view of the pulley device of

[0034] - Figure 3 is Figure 2 the view of detail A of the pulley device of Detailed Description of the Embodiments

[0035] As can be seen in Figure 1 and Figure 2 a pulley device (overall reference numeral 1) for a belt tensioning roller or a winding roller has a geometric axis X1 and includes a pulley 2, a rolling bearing 3, two protective flanges 4 and 5 adapted to cooperate with a transmission element (not shown) such as a belt or a chain.

[0036] The rolling bearing 3 includes a stationary inner ring 6 and a rotating outer ring 7. The inner ring 6 and the outer ring 7 are coaxial with respect to the axis X1 and a radial space 8 is formed therebetween. The rolling bearing 3 further includes two rows of rolling elements 9 and 10 and cages 11 and 12. The two rows of rolling elements 9 and 10 are produced in the form of balls here and are arranged between the outer ring and the inner ring. The cages 11 and 12 respectively ensure the circumferential spacing of the rolling elements 9 and 10.

[0037] The inner ring 6 and the outer ring 7 are coaxial. In the exemplary embodiment shown, the rings are solid, that is to say, the rings are obtained by machining or grinding to remove material from a metal tube, bar, forging part or rolled blank.

[0038] The inner ring 6 includes a hole 13, an outer surface 14, and both a rear lateral surface 17 and a front lateral surface 18. The cylindrical portion of the outer surface 14 is provided with raceways 15, 16. The raceways 15, 16 have a concave inner profile in the axial section and have a toroidal form suitable for the balls 9, 10.

[0039] The hole 13 of the inner ring 6 is adapted to receive a screw (not shown). The body of the screw extends axially beyond the rear lateral surface 17 of the stationary inner ring 6. The body includes a threaded portion for screwing into a corresponding clamping opening of the support of the pulley device 1.

[0040] The outer ring 7 includes a cylindrical hole 19, an outer cylindrical surface 22, and both a rear lateral surface 23 and a front lateral surface 24. The cylindrical hole 19 is provided with raceways 20, 21. The raceways 20, 21 have a concave inner profile in the axial section and have a toroidal form suitable for the balls 9, 10. The pulley 2 is mounted on the outer cylindrical surface 22.

[0041] The stationary inner ring 6 extends axially in the rear axial direction beyond the rotating outer ring 7. The rear axial direction points to the support on which the pulley device 1 is to be mounted. The rear lateral surface 17 is used to form a bearing surface of the support of the abutment device 1 for the rolling bearing 3.

[0042] The rolling bearing 3 advantageously includes an annular rear seal 25 and an annular front seal 26 to enclose the radial space 8 existing between the inner ring 6 and the outer ring 7 and accommodating the rolling elements 9, 10 on each axial side.

[0043] Advantageously, each of the seals 25, 26 includes a first end and a second end, the first end being fixed in a circumferential groove provided in the hole portion 19 of the outer ring 7, and the second end being formed by a lip that slidably contacts a part of the outer surface 14 of the inner ring 6. Thus, the radial space 8 is enclosed in an axially tightly sealed manner between the two seals 25, 26.

[0044] As an alternative, the rolling bearing may include different numbers of rows of rolling elements arranged between the outer ring and the inner ring, such as a single row of rolling elements.

[0045] As an alternative, the rolling bearing may include other types of rolling elements, such as tapered rollers, needle rollers or even cylindrical rollers.

[0046] In this embodiment, the inner ring 6 is formed as a single piece. According to an alternative embodiment (not shown), the rolling bearing 3 may include an annular spacer mounted in the inner ring 6.

[0047] The pulley 2 includes an outer cylindrical surface 27 and an inner surface 28. The outer cylindrical surface 27 is for cooperating with a transmission element such as a belt or a chain, and the inner surface 28 is firmly mounted on the outer surface 22 of the outer ring 7. The pulley has a substantially tubular form and is centered on the central axis X1. The frictional force between the outer surface 27 and the transmission element allows the transmission of rotational torque.

[0048] According to another embodiment (not shown), the transmission element may be a toothed belt. In particular, the transmission element may be a Poly-V type toothed belt, or may be any other type of toothed belt without limiting the present invention. Then, the outer surface 27 is provided with elements such as rigids or notches to cooperate with the form of the belt.

[0049] The pulley 2 further includes a rear portion 29 and a front portion 30, which axially project relative to the rear lateral surface 23 and the front lateral surface 24 of the outer ring 7, respectively. In the illustrated embodiment, these axially projecting portions 29, 30 are stages.

[0050] Advantageously, the pulley 2 can be produced from a plastic material, and preferably from polyamide, for example, from PA6 or PA66. The pulley 2 can advantageously be formed by overmoulding a plastic material on the outer ring 7 of the rolling bearing 3. As a result, excellent cohesion is formed between these parts. As an alternative, the pulley 2 can be produced from a metallic material (such as steel) and can be crimp-mounted on the outer cylindrical surface 22 of the outer ring 7. The pulley 2 can also have other forms optimized according to the application requirements.

[0051] The pulley device 1 further includes a rear protective flange 4 and a front protective flange 5 mounted on both sides of the sealed radial space 8. More specifically, the rear flange 4 covers the rear seal 25, and the front flange 5 covers the front seal 26 to provide primary protection against external contamination, especially against dust and particles.

[0052] The rear flange 4 includes a substantially radial body extending between an inner edge and an outer edge forming a hole, the inner edge of the formed hole being mounted around a cylindrical portion of the outer surface 13 of the inner ring 6, and the outer edge being mounted in a hole of an axially protruding rear portion (rear axially protruding portion) 29 of the pulley 2. The rear flange 4 abuts against the rear lateral surface 23 of the outer ring 7.

[0053] Similarly, the front flange 5 includes a substantially radial body extending between an inner edge and an outer edge forming a hole, the inner edge of the formed hole being mounted around a cylindrical portion of the outer surface 13 of the inner ring 6, and the outer edge being mounted in a hole of an axially protruding front portion (front axially protruding portion) 30 of the pulley 2. The front flange 5 abuts against the front lateral surface 24 of the outer ring 7.

[0054] The flanges are formed by cutting from a metal (e.g., steel) plate. As an option, the flanges can be made of a plastic material, e.g., made of polyamide.

[0055] According to the present invention, the rear flange 4 and the front flange 5 are each fixed to the rotating outer ring 7 by pressing the rear axially protruding portion 29 and the front axially protruding portion 30 of the pulley 2 onto the flanges 4, 5.

[0056] More specifically, the crimping portions 31 are formed by local plastic deformation of the hole portions of the rear axially protruding portion 29. These crimping portions 31 are formed toward the outer edge of the rear flange 4. Thus, the outer edge of the rear flange 4 is axially clamped between these crimping portions 31 of the pulley 2 and the rear lateral surface 23 of the rotating outer ring 7.

[0057] Similarly, the crimping portions 32 are formed by local plastic deformation of the hole portions of the front axially protruding portion 30. These crimping portions 30 are formed toward the outer edge of the front flange 5. Thus, the outer edge of the front flange 5 is axially clamped between these crimping portions 32 of the pulley 2 and the front lateral surface 24 of the rotating outer ring 7.

[0058] The axially protruding portions 29, 30 of the pulley 2 are each crimped at a plurality of positions on the outer periphery of the outer edge of the flanges 4, 5. In the illustrated embodiment, the crimping portions 31, 32 are evenly distributed circumferentially. As an option, these crimping portions can have another circumferential distribution.

[0059] Particularly advantageously, the rear flange 4 and the front flange 5 each have an inner edge forming a hole, which inner edge enters a position of a part of the outer surface 13 of the inner ring 6 that is adjacent and fixed. In this way, the flanges 4, 5 and the inner ring 6 form a labyrinth sealing means.

[0060] In addition, the technical features of different embodiments can be combined with each other in all features or only some of them. Therefore, the pulley device can be adjusted in terms of cost, performance and ease of use.

Claims

1. A pulley device (1) for a tensioning roller or a winding roller of a transmission element, the pulley device (1) comprises: - a pulley (2) having an outer surface (27) for cooperating with the transmission element; - a rolling bearing (3) provided with a rotating outer ring (7), a fixed inner ring (6) and at least one row of rolling elements (9, 10), the pulley (2) being mounted on the outer surface (22) of the outer ring (7), the inner ring (6) and the outer ring (7) being coaxial, and a radial space (8) being formed between the inner ring (6) and the outer ring (7), the at least one row of rolling elements (9, 10) being arranged in the radial space (8); and - at least one annular protective flange (4, 5) having a substantially radial body, characterized in that the pulley (2) has at least one portion (29, 30) protruding axially with respect to the lateral surfaces (23, 24) of the rotating outer ring (7), the annular protective flange (4, 5) being mounted in a hole of the axially protruding portion (29, 30), and the annular protective flange (4, 5) being fixed to the rotating outer ring (7) by pressing the axially protruding portion (29, 30) of the pulley (2) against the outer edge of the annular protective flange (4, 5), the annular protective flange (4, 5) directly bearing against the lateral surfaces (23, 24) of the rotating outer ring (7).

2. The pulley device according to claim 1, characterized in that the axially protruding portions (29, 30) of the pulley (2) are pressed at a plurality of positions on the outer periphery of the outer edge of the annular protective flange (4, 5).

3. The pulley device according to claim 1 or 2, characterized in that the annular protective flange (4, 5) has an inner edge forming a hole, and the inner edge forming the hole enters a position adjacent to the outer surface (14) of the fixed inner ring (6).

4. The pulley device according to claim 1 or 2, characterized in that the pulley device (1) further comprises a rear sealing member (25) and a front sealing member (26) that enclose the radial space (8) on each axial side.

5. The pulley device according to claim 1 or 2, characterized in that the pulley (2) is made of metal.

6. The pulley device according to claim 1 or 2, characterized in that the pulley (2) is made of a plastic material.

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