Pulley arrangements, especially for tensioning idler pulleys or moving rollers

Abstract

The pulley device (1) comprises a pulley (2) and a bearing (3). The pulley (2) has at least one C-shaped pulley portion (17, 18), the pulley portion (17, 18) having an inner portion (22; 30) mounted on the bearing (3), an outer portion (19; 27) having an outer cylindrical surface (16) for interacting with a belt or a chain, and an intermediate portion (25; 33) extending substantially radially between axial ends of the inner portion (22; 30) and the outer portion (19; 27) on one axial side of the pulley device (1). A gripping surface portion (37, 38; 39, 40) is provided on one of the outer cylindrical surface (16) of the outer ring (5) and the inner cylindrical surface (23, 31) of the inner cylindrical portion (22, 30) of the pulley portion (17, 18), and the gripping surface portion (37, 38; 39, 40) includes a plurality of notches and recesses.

Description

Technical Field

[0001] The invention relates to the field of pulley arrangements for tensioning idlers or runner rollers which are designed to interact with a chain or a belt, for example with a distribution belt of an internal combustion engine of a vehicle. Background Art

[0002] These rollers are usually used to maintain a constant tension on a belt or chain within a determined range or to locally change the path taken by the chain or belt. These are called tensioning idlers ( / idler rollers) or moving rollers, respectively. In a moving roller, the pulley is mounted to rotate on a screw ( / screw) or spindle by means of rolling bearings, and the moving roller is then attached directly or indirectly to the engine block or to an element of the tensioning idler device, such as an articulated arm or an eccentric wheel.

[0003] Document GB190509598 discloses a pulley comprising a male overlap portion and a female overlap portion which are in interlocking relationship and form a cylindrical outer portion for contact with a belt.

[0004] The main drawback of this pulley is the formation of an annular recess on the outer portion (which is adapted to support the belt when the male and female parts are tightened together). There is therefore a risk of premature belt wear.

[0005] A pulley is also known in document GB141829, which includes an outer peripheral portion for contact with the belt, an inner portion and an intermediate portion between the inner portion and the outer portion. The pulley is fastened to the outer ring of the bearing, but during use of the pulley device, the pulley may move slightly in the axial direction. In addition, with this disclosed pulley, the outer portion may deform radially inwards by bending under the action of the belt.

[0006] In document DE 20 2005 011 230 U1 it has been proposed to house a damping ring in a C-shaped pulley, the damping element being used to damp vibrations from the belt and being suitable for limiting radially inward deformations of the outer portion of the pulley. However, the pulley may still deform under heavy loads. Summary of the invention

[0007] The object of the present invention is to overcome these drawbacks by proposing a pulley that is easy to mount on bearings, has good rigidity, is suitable for avoiding premature wear of the belt and allows effective support of said belt.

[0008] To this end, the invention relates to a pulley arrangement suitable for a tensioning idler pulley or a moving roller of a belt or chain, the pulley arrangement comprising a bearing and a pulley.

[0009] The bearing comprises a rotatable outer ring and a fixed inner ring, wherein the outer ring and the inner ring are coaxial.

[0010] The pulley includes at least one pulley portion having a generally C-shaped cross-section and having an inner cylindrical portion, an outer cylindrical portion and a radial middle portion, the inner cylindrical portion having an inner cylindrical surface mounted on the outer cylindrical surface of the outer ring of the bearing, the outer cylindrical portion having an outer cylindrical surface for contacting the belt or the chain, the radial middle portion extending generally in the radial direction between the axial ends of the inner cylindrical portion and the outer cylindrical portion on an axial side of the pulley device, the pulley portion being integrally formed and defining an open end on an axial side opposite to the middle portion.

[0011] According to the present invention, a gripping surface portion is provided on one of the outer cylindrical surface of the outer ring and the inner cylindrical surface of the inner cylindrical portion of the pulley portion, wherein the gripping surface portion includes a plurality of notches and recesses.

[0012] According to further advantageous but non-mandatory aspects of the invention, such a pulley arrangement may comprise one or more of the following features:

[0013] The bearing is a rolling bearing, and at least one row of rolling elements is radially interposed between the inner ring and the outer ring.

[0014] - The rolling elements are balls.

[0015] The rolling elements are spaced equidistantly in the circumferential direction and are held by an annular cage.

[0016] The pulley is formed by only one pulley part.

[0017] - The pulley comprises two C-shaped pulley parts mounted to the outer cylindrical surface of the outer ring of the bearing.

[0018] - The open ends of the two pulley parts face each other in the axial direction, and the free ends of the outer parts of the pulley parts abut (abutment) in the axial direction.

[0019] - The two pulley parts are symmetrical with respect to a transverse radial plane passing through the centre of the bearing.

[0020] The total length of the inner parts of the two C-shaped pulley parts mounted on the outer ring is at least equal to 90% of the axial length of the outer cylindrical surface of the outer ring.

[0021] The axial length of the outer portion of the pulley part is greater than the axial length of the inner portion, the outer portion protruding axially on at least one axial side of the inner portion.

[0022] - The inner part of the pulley portion is cylindrical, having an inner cylindrical portion.

[0023] - The pulley part is made from a stamped metal sheet ( / plate) or blank.

[0024] - The inner portion of the pulley part is press-fitted onto the outer cylindrical surface of the outer ring.

[0025] - The gripping surface portion is arranged on the outer cylindrical surface of the outer ring.

[0026] - The gripping surface portion is arranged on the inner cylindrical surface of the inner cylindrical portion of the pulley part.

[0027] - The gripping surface is partly produced by a knurling process.

[0028] The pitch of the notches and recesses is comprised between 0.1 mm and 1 mm.

[0029] - said notches and recesses of the gripping surface portion have a criss-cross pattern, a rectilinear pattern or any other suitable shape.

[0030] - The gripping surface portion is annular. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The invention will now be explained with reference to the accompanying drawings which are intended as illustrative examples and not to limit the purpose of the invention. In the drawings:

[0032] - Figure 1 is an axial cross section of a pulley device according to a first embodiment of the present invention;

[0033] - Figure 2 yes Figure 1 A detailed view of the pulley device;

[0034] - Figure 3 is set at Figure 1 A three-dimensional diagram of a bearing of a pulley device;

[0035] - Figure 4 is an axial cross section of a pulley device according to a second embodiment of the present invention;

[0036] - Figure 5 yes Figure 4 A detailed view of the pulley arrangement B; and

[0037] - Figure 6 is set at Figure 4A three-dimensional view of a bearing of a pulley device. DETAILED DESCRIPTION

[0038] like Figures 1 to 3 As shown, the pulley arrangement 1 is suitable for a tensioning idler pulley or a moving roller of a belt or chain and comprises a pulley 2 adapted to interact with a belt or chain (not shown) and a rolling bearing 3 having a geometric axis X1.

[0039] The rolling bearing includes a fixed inner ring 4, a rotatable outer ring 5, two annular retainers 8, 9 and two annular seals 10, 11. Two rows of rolling elements 6 and 7 are accommodated between the inner ring 4 and the outer ring 5. In this case, the rolling elements 6 and 7 are balls. The two annular retainers 8, 9 respectively maintain the circumferential spacing of the rolling elements 6, 7.

[0040] The inner ring 4 and the outer ring 5 are coaxial and symmetrical with respect to a transverse radial plane Y3 passing through the center of the rolling bearing 3. Advantageously, the rings 4, 5 are of solid type. Solid type is understood to be a ring obtained by machining by removing material from a metal tube ( / tube blank), a bar ( / bar blank), a rough forging and / or a rolled blank by machining, grinding.

[0041] The inner ring 4 comprises a hole 12 for receiving a fastening screw 13 (shown in dotted lines) to fasten the device 1 to an external support. The inner ring also comprises an outer cylindrical surface 14 on which is formed an annular raceway whose cross section has a concave inner profile adapted to the rolling elements 6,7.

[0042] The outer ring 5 comprises a cylindrical hole 15 on which a circular ring raceway is formed, the cross section of which has a concave inner profile suitable for receiving the rolling elements 6 , 7 . The outer ring 5 also comprises an outer cylindrical surface 16 .

[0043] The pulley 2 has two pulley parts 17 , 18 , which have a generally C-shaped cross section.

[0044] The first pulley part 17 comprises an axial annular outer portion 19 providing a cylindrical outer surface 20 designed to interact with a portion of a belt or chain and a cylindrical inner surface or bore 21 .

[0045] The first pulley part 17 further comprises an axial annular inner portion 22 providing a cylindrical inner surface or bore 23 and a cylindrical outer surface 24 into which the outer cylindrical surface 16 of the outer ring 5 of the bearing 3 is mounted.

[0046] The outer portion 19 has a larger diameter than the inner portion 22, and radially surrounds the inner portion 22. Advantageously, the outer portion 19 has a larger axial length than the inner portion 22, and axially protrudes from at least one axial side of the inner portion 22.

[0047] The first pulley part 17 further comprises an annular radial middle portion 25 extending substantially radially between the axial ends of the inner cylindrical portion 22 and the outer cylindrical portion 19 at a first axial side of the pulley device 1 .

[0048] The first pulley part 17 then has a generally C-shaped cross section defining an open end 26 at one axial side of the pulley device 1. The first pulley part 17 is integrally formed.

[0049] The second pulley part 18 comprises an axial annular outer portion 27 providing a cylindrical outer surface 28 designed to interact with a portion of a chain or belt and a cylindrical inner surface or bore 29 .

[0050] The second pulley part 18 further comprises an axial annular inner portion 30 providing a cylindrical inner surface or bore 31 and a cylindrical outer surface 32 into which the outer cylindrical surface 16 of the outer ring 5 of the bearing 3 is mounted.

[0051] The outer portion 27 has a larger diameter than the inner portion 30, and radially surrounds the inner portion 30. Advantageously, the outer portion 27 has a larger axial length than the inner portion 30, and axially protrudes on at least one axial side of the inner portion 30.

[0052] The second pulley portion 18 further comprises an annular radial middle portion 33, which extends substantially radially between the axial ends of the inner cylindrical portion 30 and the outer cylindrical portion 27 on a second axial side of the pulley device 1, wherein the second axial side is axially opposite to (or opposite to) the first axial side.

[0053] The second pulley part 18 then has a generally C-shaped cross section defining an open end 34 at one axial side of the pulley device 1. The second pulley part 18 is integrally formed.

[0054] Advantageously, the pulley parts 17, 18 are each made from a thin metal sheet or blank by folding, cutting and punching.

[0055] Advantageously, the inner cylindrical portion 22 of the first pulley part 17 and the inner cylindrical portion 30 of the second pulley part 18 are press-fitted onto the outer cylindrical surface 16 of the outer ring 5 .

[0056] Advantageously, the two C-shaped pulley parts 17, 18 are symmetrical to each other with respect to the radial plane Y3. The free ends of the outer portion 19 of the first pulley part 17 and the free ends of the outer portion 27 of the second pulley part 18 are in contact with each other in the axial direction, and the open ends 26, 34 are respectively axially facing each other (open). The two outer cylindrical surfaces 20, 28 form surfaces for interacting with a belt or chain. The pulley 2 formed by the two pulley parts 17, 18 configured to be in axial contact with each other is suitable for guiding and supporting a belt or chain in an effective manner.

[0057] According to the first embodiment of the invention, the outer cylindrical surface 16 of the outer ring 5 is provided with two annular grip surface portions 37 , 38 .

[0058] like Figure 2 and Figure 3 As shown, the gripping surface portions 37, 38 each comprise a plurality of indentations and recesses. Advantageously, the pitch of the indentations and recesses is comprised between 0.1 mm and 1 mm. Advantageously, the indentations and recesses of the gripping surface portions 37, 38 have a cross pattern, a straight line pattern or any other suitable shape.

[0059] The gripping surface portions 37, 38 are advantageously manufactured by a knurling process using a knurling tool.

[0060] The outer cylindrical surface 16 comprises a first gripping surface portion 37 at a first axial side and a second gripping surface portion 38 at a second axial side.

[0061] The first gripping surface portion 37 extends axially ( / along the axial direction) over 70% of the axial length of the inner cylindrical surface 23 of the inner cylindrical portion 22 of the first pulley portion 17. The inner cylindrical surface 23 has an interference fit ( / interference fit) with the outer cylindrical surface 16, more particularly, the inner cylindrical surface 23 has an interference fit with the gripping surface portion 37. The gripping surface portion 37 increases the surface roughness of the outer cylindrical surface 16 and allows limiting any relative axial displacement between the first pulley portion 17 and the outer ring 5.

[0062] Similarly and symmetrically with respect to the radial plane Y3, the second gripping surface portion 38 extends axially over 70% of the axial length of the inner cylindrical surface 31 of the inner cylindrical portion 30 of the second pulley portion 18. The inner cylindrical surface 31 is interference fit with the outer cylindrical surface 16, more particularly, the inner cylindrical surface 31 is interference fit with the gripping surface portion 38. The gripping surface portion 38 increases the surface roughness of the outer cylindrical surface 16 and allows limiting any relative axial displacement between the second pulley portion 18 and the outer ring 5.

[0063] The pulley 2 comprises two pulley parts 17, 18 which are axially held in both axial directions relative to the outer ring 5 of the bearing 3. The pulley 2 is prevented from axial movement even in the event of severe vibrations or shocks and is suitable for effectively supporting the belt or chain for an increased and efficient service life.

[0064] As an alternative, not shown, the gripping surface portions 37 , 38 are connected to one another to form a single gripping surface portion on the outer cylindrical surface 16 of the outer ring 5 .

[0065] Figures 4 to 6 A second embodiment of the present invention is shown in FIG.

[0066] The inner cylindrical surface 23 of the inner cylindrical portion 22 of the pulley portion 17 , the inner cylindrical surface 31 of the inner cylindrical portion 30 of the pulley portion 18 are each provided with an annular gripping surface portion 39 , 40 .

[0067] like Figure 5 and Figure 6 As shown, the gripping surface portion 39 of the first pulley portion 17 includes a plurality of notches and recesses. Similarly, the gripping surface portion 40 of the second pulley portion 18 also includes a plurality of notches and recesses.

[0068] The gripping surface portions 39, 40 are advantageously manufactured by a knurling process using a knurling tool.

[0069] The inner cylindrical surface 23 of the first pulley part 17 is interference fit with the outer cylindrical surface 16, more specifically, the gripping surface portion 39 is interference fit with the outer cylindrical surface 16. The gripping surface portion 39 increases the surface roughness of the inner cylindrical surface 23 and allows limiting any relative axial displacement between the first pulley part 17 and the outer ring 5. Similarly, the inner cylindrical surface 31 of the second pulley part 18 is interference fit with the outer cylindrical surface 16, more specifically, the gripping surface portion 40 is interference fit with the outer cylindrical surface 16. The gripping surface portion 40 increases the surface roughness of the inner cylindrical surface 31 and allows limiting any relative axial displacement between the second pulley part 18 and the outer ring 5.

[0070] As an alternative not shown, the pulley arrangement 1 may comprise only one pulley portion 17 or 18. According to another alternative embodiment not shown, the pulley arrangement comprises a pulley 2 having two C-shaped pulley portions 17, 18 but mounted on the outer cylindrical surface 16 of the outer ring 5, the pulley 2 having two intermediate portions 25, 33 axially abutting each other, the open ends 26, 34 of the pulley portions 17, 18 being open at opposite axial sides of the pulley arrangement 1.

[0071] Representative non-limiting examples of the present invention are described in detail above with reference to the accompanying drawings. This detailed description is intended only to teach those skilled in the art more details for practicing the preferred aspects of the present teachings, and is not intended to limit the scope of the present invention. In addition, each of the additional features and teachings disclosed above can be used alone or in combination with other features and teachings to provide an improved pulley device.

[0072] Furthermore, various features of the representative examples described above and the various independent and dependent claims below may be combined in ways not specifically and expressly recited to provide other useful embodiments of the present teachings.

Claims

1. A pulley device, suitable for a belt or chain tensioning idler wheel or a moving roller, the pulley device comprising: - a bearing having a rotatable outer ring and a fixed inner ring, the rotatable outer ring and the fixed inner ring being coaxial; and - a pulley, provided with at least one pulley portion, the at least one pulley portion having a generally C-shaped cross-section and having an inner cylindrical portion, the inner cylindrical portion having an inner cylindrical surface mounted on the outer cylindrical surface of the rotatable outer ring of the bearing, the at least one pulley portion also having an outer cylindrical portion and a radial intermediate portion, the outer cylindrical portion having an outer cylindrical surface configured to contact the belt or chain tensioner idler wheel, the axial length of the outer cylindrical portion (19; 27) of the pulley portion (17; 18) being greater than the axial length of the inner cylindrical portion (22; 30) of the pulley portion (17; 18), the radial intermediate portion (25; 33) connecting the axial ends of the inner cylindrical portion (22; 30) and the outer cylindrical portion (19, 27) on one axial side of the pulley device (1) in an inclined manner relative to a transverse radial plane (Y3) passing through the center of the bearing (3), the pulley portion being integrally formed and defining an open end on at least one axial side opposite to the intermediate portion; It is characterized in that: the at least one pulley part also includes a gripping surface portion arranged on one of the outer cylindrical surface of the rotatable outer ring and the inner cylindrical surface of the inner cylindrical part of at least one pulley part, and the gripping surface portion includes a plurality of notches and recesses.

2. The pulley device according to claim 1, characterized in that: The pulley (2) is formed by only one pulley part.

3. The pulley device according to claim 1, characterized in that: The pulley (2) comprises two C-shaped pulley parts (17, 18) mounted on the outer cylindrical surface (16) of the outer ring (5) of the bearing (3).

4. The pulley device according to claim 3, characterized in that: The open ends (26, 34) of the two pulley parts (17, 18) face each other in the axial direction, and the free ends of the outer parts (19, 27) of the pulley parts (17, 18) abut against each other in the axial direction.

5. The pulley device according to claim 3 or 4, characterized in that: The two pulley parts (17, 18) are symmetrical with respect to a transverse radial plane (Y3) passing through the center of the bearing (3).

6. The pulley device according to any one of claims 1 to 4, characterized in that The inner cylindrical portion (22, 30) of the pulley portion (17, 18) is press-fitted onto the outer cylindrical surface (16) of the outer ring (5).

7. The pulley device according to any one of claims 1 to 4, characterized in that The gripping surface portions (37, 38; 39, 40) are manufactured by a knurling process.

8. The pulley device according to any one of claims 1 to 4, characterized in that The pitch of the notches and recesses is comprised between 0.1 mm and 1 mm.

9. The pulley device according to any one of claims 1 to 4, characterized in that The notches and recesses of the gripping surface portions (37, 38; 39, 40) have a cross pattern or a straight line pattern.

10. The pulley device according to any one of claims 1 to 4, characterized in that The gripping surface portions (37, 38; 39, 40) are annular.

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