JP2014234907A - Pulley device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of preventing occurrence of creep between an outer ring and a pulley, ensuring appropriate turning around of resin during injection molding, and improving creep-prevention reliability.SOLUTION: A pulley device 300 comprises: an inner ring 305 having an inner ring raceway 304 on an outer circumferential surface; an outer ring 307 having an outer ring raceway 306 on an inner circumferential surface; a plurality of rolling elements 308 provided between the inner ring raceway 304 and the outer ring raceway 306 so that the rolling elements 308 can freely roll; and a synthetic resin pulley 302 fixedly provided on an outer circumferential surface of the outer ring 307. An engagement groove 317 having an irregular surface formed on a bottom surface by a trapezoidal knurl is provided on the outer circumferential surface of the outer ring 307 for preventing creep.

Description

  The pulley device according to the present invention includes, for example, a mechanism for driving an auxiliary machine such as a compressor used in an air conditioner for an automobile by an endless belt, or a crank pulley and a cam fixed to an end of a crankshaft by a timing belt. It is used as a guide pulley or tension pulley that is used by being incorporated in a belt transmission mechanism such as a mechanism for transmitting rotational force to and from a cam pulley fixed to the end of the shaft.

  As a pulley device such as a guide pulley or a tension pulley that is incorporated in a belt transmission mechanism, a pulley device in which a synthetic resin pulley is fixed to an outer ring of a rolling bearing has been conventionally used in order to reduce weight and cost. It is used. FIG. 7 shows a pulley apparatus 1 incorporating a conventionally known synthetic resin pulley described in Patent Document 1, for example.

  This pulley apparatus 1 is a rolling roller which is a single-row deep groove type radial ball bearing for rotatably supporting a pulley on a support shaft or the like, and a synthetic resin pulley 2 for belting the outer peripheral surface. And a bearing 3. Among these, the rolling bearing 3 includes an inner ring 5 having a single-row inner ring raceway 4 on an outer peripheral surface, an outer ring 7 having a single-row outer ring raceway 6 on an inner peripheral surface, and between the inner ring raceway 4 and the outer ring raceway 6. And a plurality of rolling elements 8, 8 provided so as to be freely rollable. Further, sealing plates 9 and 9 are provided between the outer peripheral surfaces of both ends of the inner ring 5 and the inner peripheral surfaces of both ends of the outer ring 7, and grease filled in the space where the rolling elements 8 are installed leaks to the outside. In addition to preventing external dust and the like from entering this space. The pulley 2 is fixed to the outer peripheral surface of the outer ring 7 of the rolling bearing 3 configured as described above.

  The pulley 2 has a small diameter side cylindrical portion 10 and a large diameter side cylindrical portion 11 provided concentrically with each other. The outer peripheral surface of the intermediate portion of the small-diameter side cylindrical portion 10 and the inner peripheral surface of the intermediate portion of the large-diameter side cylindrical portion 11 are connected by a ring-shaped connecting portion 12. The reinforcing ribs 13 and 13 are provided radially. In such a pulley 2, the small-diameter side cylindrical portion 10 is fixed around the outer ring 7 constituting the rolling bearing 3 by injection molding. That is, in a state where the outer ring 7 is molded on the inner peripheral side, the molten thermoplastic resin is injected into a cavity having an inner shape corresponding to the outer shape of the pulley 2 provided in the mold. . After the thermoplastic resin has cooled and solidified, the mold is opened, and the pulley 2 is taken out of the cavity together with the rolling bearing 3 from the cavity.

  The pulley apparatus 1 configured as described above is used as, for example, a guide pulley or a tension pulley incorporated in a belt transmission mechanism that drives an auxiliary machine of an automobile. That is, the inner ring 5 constituting the rolling bearing 3 is externally fitted and fixed to a support shaft fixed to a fixed part such as a cylinder block of the engine. Then, an endless belt is stretched around the outer peripheral surface of the pulley 2. In this state, the pulley device 1 rotates the pulley 2 as the endless belt travels, and ensures the winding angle of the endless belt or the tension of the endless belt.

  By the way, in the case of the pulley device 1 in which the synthetic resin pulley 2 is fixed to the outer peripheral surface of the outer ring 7 as described above, the outer ring 7 is made of a metal material such as bearing steel. 2 has a different coefficient of linear expansion. Therefore, due to a temperature rise during use, the adhesion between the outer ring 7 and the pulley 2 may be reduced, and a relative slip (creep) may occur between the outer ring 7 and the pulley 2. As a technique for preventing such creep, there is a technique described in Patent Document 2, for example.

  A pulley apparatus 100 described in Patent Document 2 is shown in FIG. FIG. 8 is a partially cut perspective view of the pulley apparatus 100 cut along the same cross section as FIG. 7 described above. In the pulley device 100, a locking groove 117, which is a circumferential groove recessed with respect to the outer peripheral surface, is formed on the outer peripheral surface of the outer ring 107 of the rolling bearing 103, compared to the pulley device 1 shown in FIG. Yes. The groove bottom portion of the locking groove 117 has a concavo-convex surface formed by triangular knurling. FIG. 9 is a perspective view in which the synthetic resin pulley 102 is removed from the pulley device 100 so that the shape of the locking groove 117 can be seen, and FIG. 10 is a front view thereof. FIG. 11 is a cross-sectional view taken along the line AA in FIG.

A pulley 102 is fixed to the outer peripheral surface of the outer ring 107 of such a rolling bearing 103 by injection molding in the same manner as the pulley device 1 described above.
Since the locking groove 117 is formed on the outer peripheral surface of the outer ring 107 over the entire circumference, the thermoplastic resin melted at the time of the injection molding is filled. It is formed so as to fill the uneven surface 117. It is possible to prevent the occurrence of creep by meshing the uneven surface with the small diameter side cylindrical portion 110.

JP-A-10-122339 Japanese Patent Laid-Open No. 11-148550

  By the way, in the case of the locking groove by the triangular knurling process as described above, the resin may not be properly wound during the injection molding of the resin. Further, with the recent high performance of automobiles, the load and rotation speed required for the pulley tend to increase more and more, and in the structure for preventing creep by the locking groove by the triangular knurling process as described in Patent Document 2, In the future, creep may not be prevented.

  In view of the circumstances as described above, it is an object of the present invention to provide a pulley apparatus having improved reliability against creep.

  The purpose mentioned above is an inner ring having an inner ring raceway on the outer peripheral surface, an outer ring having an outer ring raceway on the inner peripheral surface, and a plurality of rolling elements provided between the inner ring raceway and the outer ring raceway so as to be freely rollable. In a pulley apparatus comprising a synthetic resin pulley fixed to the outer peripheral surface of the outer ring, the outer peripheral surface of the outer ring has a concave and convex surface formed by a trapezoidal knurl on the bottom surface to prevent creep. This is achieved by a pulley device characterized in that one or more locking grooves are provided.

  In the case of the pulley device of the present invention configured as described above, the above-mentioned locking groove can prevent creep from occurring between the outer ring and the pulley. In addition, the resin wrap-around at the time of injection molding is good, and the reliability against creep can be improved.

1 is a partially cut perspective view of a pulley apparatus showing a first embodiment of the present invention. The perspective view which removed the pulley from the pulley apparatus of FIG. The front view which removed the pulley from the pulley apparatus of FIG. BB sectional drawing of FIG. CC sectional drawing of FIG. The partial cutaway perspective view of the pulley apparatus which shows the 2nd Example of this invention. The partial cutaway perspective view of the pulley apparatus of conventional structure. The fragmentary cutaway perspective view of the pulley apparatus which has the latching groove of conventional structure. The perspective view which removed the pulley from the pulley apparatus of FIG. The front view which removed the pulley from the pulley apparatus of FIG. AA sectional drawing of FIG.

Example 1
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a pulley apparatus 200 which is an example of a first embodiment of the present invention.

  This pulley device 200 is a rolling roller which is a single-row deep groove type radial ball bearing for rotatably supporting a pulley 202 on a support shaft or the like, and a pulley 202 made of synthetic resin for belting an outer peripheral surface. And a bearing 203. Among these, the rolling bearing 203 includes an inner ring 5 having a single row of inner ring raceways 4 on an outer peripheral surface, an outer ring 207 having a single row outer ring raceway 6 on an inner peripheral surface, and a space between the inner ring raceway 4 and the outer ring raceway 6. And a plurality of rolling elements 8 provided so as to be freely rollable. Further, sealing plates 9 and 9 are provided between the outer peripheral surfaces of both ends of the inner ring 5 and the inner peripheral surfaces of both ends of the outer ring 207, so that the grease filled in the space where the rolling elements 8 are installed leaks to the outside. In addition to preventing external dust and the like from entering this space.

  On the outer peripheral surface of the outer ring 207 of the rolling bearing 203, a locking groove 217, which is a circumferential groove recessed with respect to the outer peripheral surface, is formed. The groove bottom portion of the locking groove 217 has an uneven surface formed by trapezoidal knurling. FIG. 2 is a perspective view in which the synthetic resin pulley 202 is removed from the pulley device 200 so that the shape of the locking groove 217 can be seen, and FIG. 3 is a front view thereof. 4 is a cross-sectional view taken along the line BB, which is a cross-section perpendicular to the axis of FIG. 3, and FIG. 5 is a cross-sectional view taken along the line CC of FIG.

The locking groove 217 is provided not at the center of the outer ring 207 in the axial direction but at an end portion having a large radial thickness near one axial direction. This is to ensure a certain distance between the outer ring raceway 6 and the locking groove 217 in order to avoid a decrease in rigidity due to the radial thickness of the outer ring 207 being reduced by the locking groove 217. Further, by providing the locking groove 217 on the inner side in the axial direction (on the rolling element 8 side) than the sealing plate 9, a groove for attaching the sealing plate 9 provided on the inner peripheral surface of the outer ring 207 and the locking groove 217 are provided. Similarly, a certain interval is secured.
In this embodiment, one locking groove 217 is provided at a position close to one axial direction of the outer ring 207. However, two locking grooves are provided on both sides of the outer ring raceway 6 in the axial direction. Also good.

As shown in FIGS. 2 to 5, the shape of the locking groove 217 is such that substantially trapezoidal concave portions are arranged on the circumference at the bottom of the circumferential groove having a certain width and certain depth. As shown in FIGS. 4A and 5A, substantially trapezoidal concave portions having the same shape are arranged at a single pitch at the bottom of the circumferential groove. However, the shape is not limited to this, and as shown in FIG. 4B, the substantially trapezoidal concave portions may have a circumferential discontinuous pitch, and the circumferential widths of the concave portions are different. Also good. Moreover, as shown in FIG.4 (c), the radial direction depth of each recessed part may differ.
Further, the locking groove 217 is provided with a back portion at the bottom of the circumferential groove as shown in FIG. Thus, in order to facilitate processing, side grooves that are deeper than the groove bottom of the circumferential groove may be provided at both ends in the axial direction of the circumferential groove.
Further, as shown in FIGS. 4 (d) and 5 (c), a concave portion in which substantially trapezoidal concave portions are arranged on the circumference directly on the outer peripheral surface of the outer ring 207, not on the bottom of the circumferential groove. A column may be provided. This is not strictly a groove, but in the present specification and claims, such a thing is also referred to as a locking groove 217 for convenience.

  The pulley 202 has a small diameter side cylindrical portion 210 and a large diameter side cylindrical portion 11 provided concentrically with each other. The outer peripheral surface of the intermediate portion of the small-diameter side cylindrical portion 210 and the inner peripheral surface of the intermediate portion of the large-diameter side cylindrical portion 11 are connected by a ring-shaped connecting portion 12. The reinforcing ribs 13 and 13 are provided radially. In such a pulley 202, the small-diameter side cylindrical portion 210 is fixed around the outer ring 207 constituting the rolling bearing 203 by injection molding. That is, in a state where the outer ring 207 is molded on the inner peripheral side, the molten synthetic resin is poured into a cavity having an inner shape corresponding to the outer shape of the pulley 202 provided in the mold. Then, after the synthetic resin is cooled and solidified, the mold is opened, and the pulley 202 is taken out from the cavity together with the rolling bearing 203.

  Since the outer circumferential surface of the outer ring 207 is formed with a locking groove 217 over the entire circumference, since the synthetic resin melted at the time of this injection molding is filled, the small diameter side cylindrical portion 210 has the locking groove 217. It is formed so as to fill the uneven surface. It is possible to prevent the occurrence of creep by meshing the uneven surface with the small diameter side cylindrical portion 210.

  Further, the radial thickness of the outer ring 207 is set to be thicker than the radial thickness of the inner ring 5. This is to suppress a decrease in rigidity due to the locking groove 217 as described above and at the same time suppress deformation of the outer ring 207, particularly the outer ring raceway 6, due to a molding pressure applied to the outer ring 207 during injection molding.

(Example 2)
FIG. 6 shows a pulley apparatus 300 that is an example of the second embodiment of the present invention.
This pulley device 300 includes a synthetic resin pulley 302 for belting an outer peripheral surface, and a rolling bearing 303 which is a double row angular ball bearing for rotatably supporting the pulley 302 on a support shaft or the like. Consists of Among them, the rolling bearing 303 includes an inner ring 305 having double-row inner ring raceways 304 and 304 on the outer peripheral surface, an outer ring 307 having double-row outer ring raceways 306 and 306 on the inner peripheral face, and the inner ring raceway 304 and outer ring raceway. A plurality of rolling elements 308 and 308 are provided between 306 and 306 so as to freely roll. Further, sealing plates 309 and 309 are provided between the outer peripheral surfaces of both ends of the inner ring 305 and the inner peripheral surfaces of both ends of the outer ring 307, and the grease filled in the space where the rolling elements 308 are installed leaks to the outside. In addition to preventing external dust and the like from entering this space.

  On the outer peripheral surface of the outer ring 307 of the rolling bearing 303, a locking groove 317 that is a circumferential groove recessed with respect to the outer peripheral surface is formed. An uneven surface is formed on the groove bottom of the locking groove 317 by trapezoidal knurling. The shape of the locking groove 317 is the same shape as the locking groove 217 of the pulley apparatus 200 according to the first embodiment described above.

  The locking groove 317 is provided between the axial direction of the outer ring 307 and the double-row outer ring raceways 306 and 306, and has a thick radial thickness at a substantially central part in the axial direction. This is for avoiding a decrease in rigidity due to the radial thickness of the outer ring 307 being reduced by the locking groove 317. In the present embodiment, one locking groove 317 is provided at a substantially central portion in the axial direction. However, like the locking groove 217 of the pulley device 200 according to the first embodiment described above, one axial groove is provided. A locking groove may also be provided at the end of each or both ends in the axial direction. Further, these may be combined to provide one to three locking grooves.

  The pulley 302 has a small-diameter side cylindrical portion 310 and a large-diameter side cylindrical portion 311 provided concentrically with each other, like the pulley 202 of the pulley device 200 according to the first embodiment described above. The outer peripheral surface of the intermediate portion of the small diameter side cylindrical portion 310 and the inner peripheral surface of the intermediate portion of the large diameter side cylindrical portion 311 are connected by an annular connecting portion 312, and a plurality of each are provided on both side surfaces of the connecting portion 312. The reinforcing ribs 313 and 313 are provided radially. In such a pulley 302, the small-diameter side cylindrical portion 310 is fixed around the outer ring 307 constituting the rolling bearing 303 by injection molding. That is, molten synthetic resin is injected into a cavity having an inner shape corresponding to the outer shape of the pulley 302 provided in the mold in a state where the outer ring 307 is molded on the inner circumferential side. Then, after the synthetic resin is cooled and solidified, the mold is opened, and the pulley 302 is taken out of the cavity together with the rolling bearing 303.

  Since the outer circumferential surface of the outer ring 307 is formed with a locking groove 317 over the entire circumference, since the synthetic resin melted at the time of this injection molding is filled, the small diameter side cylindrical portion 310 has the locking groove 317. It is formed so as to fill the uneven surface. It is possible to prevent the occurrence of creep by meshing the uneven surface with the small diameter side cylindrical portion 310.

  Further, the radial thickness of the outer ring 307 is set to be thicker than the radial thickness of the inner ring 305. This is to suppress a decrease in rigidity due to the locking groove 317 as described above and at the same time suppress deformation of the outer ring 307, particularly the outer ring raceway 306, due to molding pressure applied to the outer ring 307 during injection molding.

  In this embodiment, examples of the single-row deep groove type radial ball bearing and the double-row angular ball bearing have been described as the rolling bearing. However, the rolling bearing is not limited to this. For example, the rolling element may be a cylindrical roller or a tapered roller.

  As described above, according to the pulley device of the present invention, it is possible to prevent the occurrence of creep between the outer ring and the pulley by the locking groove, and the resin wrap-around during the injection molding is good. Because it can improve the reliability against creep, for example, it is fixed to the end of the crankshaft by an endless belt or a mechanism that drives an auxiliary machine such as a compressor used in an air conditioner for automobiles, or by a timing belt. It can be suitably used as a guide pulley or a tension pulley that is used by being incorporated in a belt transmission mechanism such as a mechanism for transmitting rotational force between the crank pulley and the cam pulley fixed to the end of the camshaft.

DESCRIPTION OF SYMBOLS 1 Pulley apparatus 2 Pulley 3 Rolling bearing 4 Inner ring raceway 5 Inner ring 6 Outer ring raceway 7 Outer ring 8 Rolling element 9 Sealing plate 10 Small diameter side cylindrical part 11 Large diameter side cylindrical part 12 Connection part 13 Reinforcement rib 100 Pulley apparatus 102 Pulley 103 Rolling bearing 107 Outer ring 110 Small diameter side cylindrical portion 117 Locking groove 200 Pulley device 202 Pulley 203 Rolling bearing 207 Outer ring 210 Small diameter side cylindrical portion 217 Locking groove 300 Pulley device 302 Pulley 303 Rolling bearing 304 Inner ring raceway 305 Inner ring 306 Outer ring raceway 307 Outer ring 308 Rolling body 309 Sealing plate 310 Small diameter side cylindrical portion 311 Large diameter side cylindrical portion 312 Connection portion 313 Reinforcement rib 317 Locking groove

Claims (3)

An inner ring having an inner ring raceway on the outer peripheral surface;
An outer ring having an outer ring raceway on the inner peripheral surface;
A plurality of rolling elements provided between the inner ring raceway and the outer ring raceway so as to be freely rollable;
A synthetic resin pulley fixed to the outer peripheral surface of the outer ring;
In the pulley apparatus provided with
The pulley apparatus according to claim 1, wherein one or more locking grooves for preventing creep are formed on the outer peripheral surface of the outer ring.   The pulley apparatus according to claim 1, wherein the pulley is fixed to the outer peripheral surface of the outer ring by injection molding, and molten resin is filled and solidified in the locking groove at the time of injection molding. The inner ring is an inner ring having double-row inner ring raceways on the outer peripheral surface;
The outer ring is an outer ring having a double row outer ring raceway on the inner peripheral surface,
The pulley device according to claim 1, wherein the locking groove is provided in a substantially central portion in the axial direction of the outer ring.

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