JP2007263293A - Pulley device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulley device that hardly causes the generation of a creep between an outer ring of a bearing and a pulley, also hardly causes deterioration in the quality of grease in the bearing, and is facilitated in recycling. <P>SOLUTION: A ring-shaped joint member 3 composed of a polymeric material is arranged between the outer ring 11 of the bearing 1 and the light metal pulley 2. A thermal expansion coefficient of the joint member 3 is set larger than a thermal expansion coefficient of the pulley 2, and a thermal expansion coefficient of the outer ring 11 is set smaller than the thermal expansion coefficient of the pulley 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pulley apparatus, and more particularly to a pulley apparatus suitable for use in a tensioner or idler of a timing belt of an automobile engine.

  Conventionally, for example, in a pulley device used in a tension belt or idler of a timing belt of an automobile engine, in order to reduce the weight, reduce the cost, and reduce the weight, the outer peripheral surface of the metal outer ring of the bearing is used. There is one in which a resin pulley is integrally formed (see Japanese Patent Laid-Open No. 2001-200197).

  However, since the conventional pulley device has different thermal expansion coefficients between the outer ring material and the pulley material, creep is generated between the bearing outer ring and the pulley due to a difference in thermal expansion when the temperature rises. There's a problem.

In addition, since the resin pulley has poor heat dissipation, heat generated by the bearing and frictional heat generated between the resin pulley and the belt are not sufficiently dissipated and accumulated in the resin pulley. The temperature of the bearing rises. Here, there is a problem that the grease in the bearing is easily deteriorated due to the rise in the temperature of the bearing, and the life of the bearing is shortened. Further, since the resin pulley is inferior in recyclability, there is a problem that the use of the resin pulley is not preferable from the viewpoint of effective use of resources and the viewpoint of environmental preservation.
JP 2001-200197 A

  Accordingly, an object of the present invention is to provide a pulley device in which creep is unlikely to occur between the outer ring of the bearing and the pulley, grease in the bearing is hardly deteriorated, and recycling is easy.

In order to achieve the above object, the pulley device of the present invention is:
A bearing having an outer ring, an inner ring and rolling elements;
A light metal pulley,
Provided between the inner peripheral surface of the pulley and the outer peripheral surface of the outer ring, and an annular joint member made of a polymer material,
A thermal expansion coefficient of the pulley is larger than a thermal expansion coefficient of the outer ring, and a thermal expansion coefficient of the joint member is larger than a thermal expansion coefficient of the pulley.

  According to the present invention, since the joint member having a thermal expansion coefficient larger than the thermal expansion coefficient of the pulley is interposed between the pulley and the bearing, the temperature of the pulley device rises and the pulley Even if it thermally expands in a direction away from the bearing, the joint member having a thermal expansion larger than that of the pulley expands so as to compress the bearing, and the outer ring can be restrained by the pulley. Therefore, it is possible to suppress the occurrence of creep between the outer ring of the bearing and the pulley.

  Further, according to the present invention, since the pulley is made of light metal, heat dissipation can be improved as compared with a resin pulley, and heat generated in the bearing, and the light metal pulley and belt can be improved. Friction heat generated between the two can be sufficiently dissipated to the outside. Therefore, an increase in the bearing temperature can be suppressed, the speed of deterioration of the grease in the bearing can be delayed, and the life of the bearing can be extended. Further, since the grease is hardly deteriorated, it is possible to refrain from using an expensive lubricating oil such as a heat-resistant high-performance grease, thereby reducing the cost of the pulley device.

  Further, according to the present invention, since the pulley is made of light metal, the strength can be increased as compared with a conventional resin pulley. Therefore, since the thickness of each part of the pulley can be reduced, the pulley device can be reduced in weight.

  Further, according to the present invention, since the pulley made of light metal is used, the pulley can be recycled, and the ratio of the recyclable portion in the entire apparatus can be increased. Therefore, the reusability of resources can be improved and it can contribute to environmental conservation.

  According to the pulley device of the present invention, it is possible to suppress the occurrence of creep between the outer ring of the bearing and the pulley. Further, the weight of the apparatus can be reduced, the grease in the bearing can be hardly deteriorated, and the life of the bearing can be extended. Moreover, the ratio of the recyclable part in the whole apparatus can be increased, the reusability of resources can be improved, and it can contribute to environmental conservation.

  FIG. 1 is a front view of a pulley apparatus 100 according to an embodiment of the present invention. 2 is a cross-sectional view taken along the line XX of FIG.

  As shown in FIG. 2, the pulley device 100 includes a ball bearing 1 as an example of a bearing, a light metal pulley 2, and a joint member 3 disposed between the ball bearing 1 and the pulley 2.

  The ball bearing 1 includes an outer ring 11, an inner ring 12, and a ball 13 disposed between the outer ring 11 and the inner ring 12. The outer ring 11, the inner ring 12 and the balls 13 are made of a steel material such as high carbon chromium bearing steel (SUJ2). A plurality of the balls 13 are arranged at predetermined intervals in the circumferential direction between the raceway grooves of the outer ring 11 and the raceway grooves of the inner ring 12 while being held by a cage (not shown). Further, both end portions in the axial direction of the annular space 14 formed by the outer ring 11 and the inner ring 12 are sealed by seal members 16 and 16, and grease is sealed therein. Here, the sealing members 16 and 16 are schematically illustrated because the illustrated space is narrow. The seal members 16 and 16 are configured to slide with respect to the inner ring 12.

  The pulley 2 is made of, for example, a light metal such as aluminum, aluminum alloy, magnesium, or magnesium alloy. The thermal expansion coefficient of these materials is larger than the thermal expansion coefficient of the steel material constituting the outer ring 11 and smaller than the thermal expansion coefficient of the polymer material constituting the joint member 3. Thus, in this embodiment, since the said pulley 2 is a light metal, heat dissipation can be improved compared with the conventional resin pulley. Accordingly, the grease of the ball bearing 1 and the temperature of the belt stretched around the outer peripheral surface of the pulley 2 can be kept at a low temperature, and the life of the grease of the ball bearing 1 and the belt can be extended as compared with the resin pulley. it can. Further, since the grease is difficult to deteriorate, it is possible to refrain from using an expensive lubricating oil such as a heat-resistant high-performance grease, and the cost of the pulley device 100 can be suppressed.

  Furthermore, since the pulley 2 is made of light metal, the strength of the pulley 2 can be increased. Therefore, compared with the conventional resin pulley, the thickness of each part of the pulley 2 can be reduced, and the pulley 2 can be reduced in weight.

  As shown in FIG. 1, the pulley 2 is arranged on the outer periphery of the annular boss portion 21 and the boss portion 21 at a predetermined interval in the radial direction of the boss portion 21 and concentrically with the boss portion 21. The annular rim portion 22 and a plurality of plate-like spoke portions 23 extending radially from the boss portion 21 toward the rim portion 22 in the radial direction of the boss portion 21 in the circumferential direction of the boss portion 21. ing. The boss portion 21, the rim portion 22, and the plurality of spoke portions 23 are integrally formed by extrusion molding. In addition to the inner periphery and outer periphery of the boss portion 21 and the inner periphery and outer periphery of the rim portion 22 being planes parallel to the axis, the side surface of the plate-like spoke portion 23 is parallel to the central axis of the pulley device 100. Since it consists of a plane, this pulley 2 can be manufactured by extrusion molding.

  As shown in FIG. 1, a space 24 surrounded by the boss portion 21, the rim portion 22 and the two spoke portions 23, 23 penetrates in the axial direction. By forming the space 24 penetrating in the axial direction in the pulley 2, the weight of the pulley 2 is reduced and the manufacturing cost of the pulley 2 is reduced. A belt is stretched around the outer peripheral surface 22 a of the rim portion 22. Since the space 24 penetrating in the axial direction is formed, air can be passed in the axial direction in addition to good heat dissipation resulting from the fact that the material of the pulley 2 is made of light metal, and the pulley 2 is made efficient. Can be cooled. Accordingly, the temperature of the pulley 2 can be kept low, so that the belt in contact with the pulley 2 can be hardly deteriorated and the life of the belt can be extended.

  As shown in FIG. 2, the axial width of the boss portion 21 is substantially equal to the axial width of the outer ring 11, while the axial width of the rim portion 22 is the radial width of the rim portion 22. It is wider than the axial width of the boss portion 21 located inward. Further, as shown in FIGS. 1 and 2, the side surface 25 facing the spoke portion 23 adjacent to the spoke portion 23 in each spoke portion 23 is formed in parallel to the axial direction. As shown in FIG. 2, the shape of both end edges 30 of the side surface 25 is a parabolic shape symmetrical to the vertical bisector of the central axis of the pulley 2, and the side surface 25 has a substantially ginkgo leaf shape. It has a shape.

  On the other hand, the front surface 27 (one surface of the surfaces connecting the two side surfaces 25 of the spoke portion 23) and the rear surface 28 (the surface connecting the two side surfaces 25 of the spoke portion 23) of the spoke portion 23. The shape of the other surface is a vertically long plane with a narrow width that connects the rim portion 22 to the boss portion 21. That is, the spoke part 23 is a plate-like member in the shape of a ginkgo leaf. 2, the front surfaces 27, 27... Of the plurality of spoke portions 23 are located on the same rotational surface with the central axis of the pulley device as the center, and the rear surface 28 of the spoke 23. , 28... Are located on the same rotational surface centered on the central axis, and are arranged in the circumferential direction without any irregularities. The plate-like spoke portion 23 firmly supports the boss portion 21 and the rim portion 22 and is robust against an external force in the axial direction.

  In this embodiment, the shape of both end edges of the side surface 25 of the spoke 23 is a substantially parabolic shape. However, in the present invention, the shape of both end edges of the side surface of the spoke is a curved shape formed of a part of an ellipse that expands in the axial direction as going outward in the radial direction, and in the axial direction as going outward in the radial direction. The shape may be a linear shape that expands toward the end, or a hyperbolic shape that expands toward the outside in the radial direction. Further, the shape of both end edges of the side surface of the spoke may be a linear shape parallel to a plane perpendicular to the central axis of the pulley device.

  It was confirmed that the pulley 2 did not make wind noise during operation. The reason for this is not clear, but since the side surface 25 of the plate-like spoke portion 23 is a surface parallel to the axial direction, there is no pumping action even if the pulley rotates, and it rotates while holding air. It is thought that this is because. Further, the front surfaces 27, 27,... Of the plurality of spoke portions 23 are located on the same rotation surface centered on the central axis of the pulley device, and the rear surfaces 28, 28,. , Which are located on the same plane of rotation centered on the central axis and are lined up in the circumferential direction without any unevenness, so that the flow of wind that moves radially outward by the centrifugal force at the spokes 23 It is thought that it is one reason that can be rectified. Paradoxically speaking, when the side surface of the plate-like pulley is inclined with respect to the axial direction, it is considered that the blowing noise and wind noise are easily generated as the pulley rotates.

  The pulley 3 is manufactured by a method in which a light metal material is extruded at a high temperature. First, a rod-like body having a cross-sectional shape of the front view of FIG. 1 in which the boss portion 21, the rim portion 22 and the spoke portion 23 are integrated is formed by extrusion molding, and this is formed into a shaft of the rim portion 22 of the pulley 3. The boss portion 21, the rim portion 22 and the spoke portion 23 are formed by cutting the front and rear surfaces appropriately, and the boss portion 21, the rim portion 22 and the spoke portion 23 are integrated. A pulley is manufactured. Thus, since the side surface 25 of the spoke part 23 consists of a surface parallel to an axial direction, the said pulley 2 can process the pulley 2 by extrusion molding. Therefore, mass production of the pulley 2 is possible, and the manufacturing cost of the pulley 2 can be reduced.

  The joint member 3 has an annular shape. As shown in FIG. 2, the joint member 3 is interposed between the outer ring 11 and the boss portion 21. The joint member 3 is provided between the outer peripheral surface 11 a of the outer ring 11 and the inner peripheral surface 21 a of the boss portion 21. The inner peripheral surface of the joint member 3 covers the entire outer peripheral surface 11 a of the outer ring 11, and the outer peripheral surface of the joint member 3 supports the entire inner peripheral surface 21 a of the boss portion 21. The joint member 3 is made of, for example, a plastic material such as rubber or nylon, an elastomer, or glass fiber, and the thermal expansion coefficient of the material of the joint member 3 is higher than the thermal expansion coefficient of the material of the outer ring 11. It is larger than the thermal expansion coefficient of the material of the pulley 2, that is, the light metal.

  Thus, since the joint member 3 having a thermal expansion coefficient larger than the thermal expansion coefficient of the pulley 2 is interposed between the pulley 2 and the outer ring 11, the temperature of the pulley device rises and the pulley 2 becomes a ball. Even if the thermal expansion is performed in a direction away from the bearing 1, the joint member 3 having a thermal expansion larger than that of the pulley 2 is expanded so as to compress the ball bearing 1, and the outer ring 11 can be restrained by the pulley 2. Therefore, the outer ring 11 and the boss portion 21 are not separated from each other, and creep does not occur between the outer ring 11 of the ball bearing 1 and the pulley 2.

  The ball bearing 1, the pulley 2, and the joint member 3 are integrally formed by the following method, for example. First, the ball bearing 1 and the pulley 2 are arranged on the same plane, and then the outer peripheral surface 11a of the outer ring 11 of the ball bearing 1 and the boss portion of the pulley 2 while compressing the flexible joint member 3 made of a polymer material. 21 between the inner circumferential surface 21a of the joint member 3 until both end portions in the axial direction of the joint member 3 engage with both side surfaces of the outer ring 11 and the boss portion 21 in the axial direction. The joint member 3 is integrally formed. If this method using the flexibility of the material of the joint member 3 is used, the bonding can be reliably performed without using an adhesive. Here, the method of pushing the molded joint member 3 while compressing it has been described. However, by filling a polymer material between the pulley 2 and the outer ring 11 by an injection molding method, the ball bearing 1, the pulley 2 and It goes without saying that the joint member 3 may be integrated. Moreover, although the pulley apparatus 100 of the said embodiment had the ball bearing 1, it cannot be overemphasized that the pulley apparatus of this invention may have rolling bearings other than ball bearings, such as a roller bearing. It is.

It is a front view of the pulley apparatus of one Embodiment of this invention. It is sectional drawing of the pulley apparatus of one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ball bearing 2 Pulley 3 Joint member 11 Outer ring 12 Inner ring 21 Boss part 22 Rim part 23 Spoke part 100 Pulley device

Claims (1)

A bearing having an outer ring, an inner ring and rolling elements;
A light metal pulley,
Provided between the inner peripheral surface of the pulley and the outer peripheral surface of the outer ring, and an annular joint member made of a polymer material,
The pulley apparatus, wherein a thermal expansion coefficient of the pulley is larger than a thermal expansion coefficient of the outer ring, and a thermal expansion coefficient of the joint member is larger than a thermal expansion coefficient of the pulley.

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