JP2018119586A - Pulley device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulley device that has high anti-creeping performance, easily radiates heat generated in a bearing from an outer ring to have improved heat radiating properties of the bearing, and hardly transfers heat generated at a rim part into the bearing.SOLUTION: A pulley device comprises a roller bearing 20 and a synthetic resin-made pulley part 30 formed on an outer peripheral surface 21b of the roller bearing 20, and the pulley part 30 has a boss part 31 formed on the outer peripheral surface 21b of the roller bearing 20, a rim part 32 arranged concentrically on an outer diameter side of the boss part 31, and a flange part 33 radially coupling the boss part 31 and rim part 32 to each other. A plurality of projections 25 which extend from the roller bearing 20, radially outward, or axially, i.e. in at least one of the three directions are formed at substantially equal intervals in a peripheral direction with wide faces directed to the peripheral direction, and the projection parts 25 are partially exposed from the boss part 31.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a pulley device, for example, an idler pulley or a tensioner pulley of a driving belt of an engine accessory mounted on an automobile or an agricultural machine, and a pulley device used for an idler pulley or a tensioner pulley of a timing belt. .

  As a conventional pulley apparatus, a pulley apparatus including a rolling bearing and a metal pulley portion attached to an outer diameter surface of an outer ring of the rolling bearing is known. Since these pulley devices are required to reduce weight and cost, in recent years, instead of metal pulley parts, resin pulley parts are integrally formed by injection molding on the outer diameter surface of the outer ring of the rolling bearing. A pulley device is known.

  However, the pulley device in which the resin pulley part is integrally formed with the outer ring in this way has different linear expansion coefficients between the metal outer ring and the resin pulley part. In addition to a decrease in the coupling force between the outer ring and the resin pulley, a high belt load, relative deformation in the circumferential direction between the outer ring and the resin pulley due to deformation of the outer ring and the resin pulley during high-speed rotation, That is, creep may occur.

  In order to improve the creep resistance of such a pulley device, for example, in the pulley device disclosed in Patent Document 1 below, the outer peripheral surface of the outer ring of the rolling bearing is knurled. By this knurling process, when the resin pulley part is integrally formed on the outer diameter surface of the outer ring by injection molding, the bond strength between the outer ring and the pulley part is increased to improve the creep resistance.

  By the way, recently, demands for higher belt load and higher speed for pulley devices have become more severe, and in the near future, it may become impossible to cope with only the improvement of creep resistance by conventional knurling.

  As the belt load and the rotation speed increase further, it can be predicted that the amount of heat generated by the rolling bearing during operation increases. If the pulley is made of metal, heat can be expected to be radiated from the pulley, but if the pulley is made of resin, the outer peripheral surface of the outer ring of the rolling bearing is covered with the resin pulley. The heat generated in is difficult to dissipate. Therefore, there is a concern that if the heat generation amount of the rolling bearing increases due to the high belt load and high speed rotation, the temperature of the rolling bearing rises and the resin of the knurled portion softens, so that creep is more likely to occur. . In addition, there is a concern that the grease inside the rolling bearing is deteriorated by heat and the bearing life is shortened.

  In order to solve such a problem, the following Patent Document 2 discloses that a resin pulley is formed after press fitting a disk-shaped metal plate into an outer ring of a rolling bearing, and a disk-shaped metal is formed from a window opened in a flange portion of the pulley. A technique for releasing heat inside the bearing by exposing a part of the plate is disclosed. However, in the configuration in which the disk-shaped metal plate reaches the vicinity of the rim portion of the pulley as described above, the heat generated by the friction between the rim portion and the belt is transmitted to the bearing through the metal plate, and instead the bearing temperature. There was a risk of urging the rise.

International Publication No. 2013/002284 JP 2009-014119 A

  The present invention has been made in view of the above-described problems, has high creep resistance, and can easily dissipate the heat generated inside the bearing from the outer ring to improve the heat dissipation of the bearing. Another object of the present invention is to provide a pulley apparatus in which heat generated in the rim portion is difficult to be transmitted to the inside of the bearing.

The above object of the present invention can be achieved by the following constitution.
(1) a rolling bearing, and a synthetic resin pulley portion formed on an outer peripheral surface of the rolling bearing, wherein the pulley portion includes a boss portion formed on the outer peripheral surface of the rolling bearing, and the boss portion. A pulley device having a rim portion concentrically disposed on the outer diameter side of the roller, and a flange portion that connects the boss portion and the rim portion in a radial direction, and is a radially outer side or an axial direction from the rolling bearing. Among the three directions, a plurality of convex portions extending in at least one direction are formed at substantially equal intervals in the circumferential direction so that a wide surface is directed in the circumferential direction, and a part of the convex portions is the boss. Pulley device which is exposed from the part.
(2) The pulley apparatus according to (1), wherein the convex portion is formed from an outer peripheral surface of the rolling bearing to an axial end surface.
(3) D2 ≦ D1 ≦ (D2 + D3) where D1 is the diameter of the virtual circle connecting the radial tips of the convex portions, D2 is the diameter of the outer peripheral surface of the boss portion, and D3 is the diameter of the inner peripheral surface of the rim portion. ) / 2, and the pulley apparatus according to (1).
(4) According to (1) or (2), the rolling bearing includes a cylindrical collar member fitted to an outer peripheral surface of an outer ring, and the convex portion is formed on the collar member. The pulley apparatus as described.
(5) The pulley apparatus according to (1) or (2), wherein the convex portion is formed on an outer ring of the rolling bearing.

  According to the present invention, a plurality of convex portions extending in at least one of the three directions, either radially outside or axially, from the rolling bearing are formed at substantially equal intervals in the circumferential direction. Since the portion is exposed from the boss portion, the outside air can be directly applied to the convex portion of the rolling bearing. Thereby, since the heat generated inside the bearing can be easily radiated from the convex portion, the heat radiation performance of the bearing can be improved. As a result, deterioration of the grease inside the bearing can be suppressed, so that the bearing life can be extended. Moreover, since the temperature rise of the boss | hub part of a pulley part can be suppressed, softening of the resin of a boss | hub part can be suppressed. Furthermore, since the convex portion has a wide surface in the circumferential direction, the resin-made pulley portion can be effectively prevented from rotating relative to the bearing outer ring in the circumferential direction, and high creep resistance can be obtained. .

It is a perspective view explaining a 1st embodiment of a pulley device concerning the present invention. It is a perspective view of the rolling bearing shown in FIG. It is a cross-sectional perspective view of the pulley apparatus shown in FIG. It is a perspective view explaining 2nd Embodiment of the pulley apparatus which concerns on this invention. It is a perspective view of the rolling bearing shown in FIG. It is a perspective view explaining 3rd Embodiment of the pulley apparatus which concerns on this invention.

  Hereinafter, each embodiment of a pulley device concerning the present invention is described in detail based on a drawing.

  The pulley apparatus 10 of 1st Embodiment is provided with the rolling bearing 20 and the pulley part 30 formed in the outer peripheral surface of the outer ring | wheel 21 of the rolling bearing 20, as shown in FIGS.

  As shown in FIGS. 2 and 3, the rolling bearing 20 includes an outer ring 21 having an outer ring raceway surface 21a on an inner circumferential surface, an inner ring 22 having an inner ring raceway surface 22a on an outer circumferential surface, an outer ring raceway surface 21a and an inner ring raceway surface. A plurality of balls 23 arranged so as to be freely rotatable with respect to 22a, and seal members 24 which are attached to both ends in the axial direction of the rolling bearing 20 and seal between the bearing space and the outside.

  As shown in FIG. 1, the pulley portion 30 is a cylindrical boss portion 31 that is attached to the outer peripheral surface of the rolling bearing 20 and a cylindrical shape that is concentrically disposed on the outer diameter side of the boss portion 31 and on which a belt (not shown) is wound. Rim portion 32, and a disc-shaped flange portion 33 that connects the axial intermediate portion of the outer peripheral surface of the boss portion 31 and the axial intermediate portion of the inner peripheral surface of the rim portion 32 in the radial direction. Further, a plurality of reinforcing ribs 34 are formed radially on the both side surfaces of the flange portion 33 at substantially equal intervals in the circumferential direction. And the pulley part 30 is formed in the outer peripheral surface of the rolling bearing 20 by the injection molding of the synthetic resin.

  On the outer peripheral surface 21b of the outer ring 21 of the rolling bearing 20, a thin plate-like convex portion 25 extending radially in the radial direction over the entire axial width along the axial direction has a wide surface in the circumferential direction. A plurality are formed at substantially equal intervals in the circumferential direction. The diameter D1 of the virtual circle connecting the radial ends of the plurality of convex portions 25 is equal to or larger than the diameter D2 of the outer peripheral surface 31a of the boss portion 31. Therefore, a part of the convex part 25 is exposed. That is, the radial front end surface of the convex portion 25 is viewed from the outer peripheral surface 31a of the boss portion 31, or the radial front end portion of the convex portion 25 protrudes from the outer peripheral surface 31a. Here, the plurality of reinforcing ribs 34 on both side surfaces of the flange portion 33 is an integral multiple of the convex portion 25, and the radial front end portion of the convex portion 25 protrudes from the circumferential central portion of the adjacent reinforcing rib 34. ing. The radial tip end of the protruding convex portion 25 has a higher heat dissipation effect as the surface area of the portion protruding from the outer peripheral surface 31a is larger.

  However, if the height in the radial direction of the convex portion 25 is too high, the heat of the rim portion 32 is transferred to the bearing, so as shown in FIG. 3, (the diameter D2 of the outer peripheral surface 31a of the boss portion 31) ≦ ( The diameter D1 of the virtual circle connecting the radial tips of the convex portions 25) ≦ {(the diameter D2 of the outer peripheral surface 31a of the boss portion 31) + (the diameter D3 of the inner peripheral surface of the rim portion)} / 2. desirable.

  In addition, since the convex part 25 which protruded from the outer peripheral surface 31a of the boss | hub part 31 has faced the surface in the circumferential direction, since the projection area which touches external air is large, it can thermally radiate efficiently.

  Even if the radial front end of the convex portion 25 is not exposed and the radial front end of the convex portion 25 is buried in the boss portion 31, a heat dissipation effect cannot be obtained, but the convexity is higher than the uneven step of the knurled. By increasing the height in the radial direction of the portion 25, it is possible to obtain a higher creep prevention effect than the conventional knurling creep prevention mechanism.

  As described above, according to the pulley device 10 of the present embodiment, the outer ring 21 of the outer ring 21 is formed with a plurality of radially extending projections 25 in the circumferential direction. Since a higher binding force than that of the pulley portion can be expected, a high creep prevention effect can be obtained.

  Further, by exposing a part of the convex portion 25 from the outer peripheral surface 31 a of the boss portion 31, outside air is applied to the radial front end portion of the convex portion 25 of the metal outer ring 21 or the radial outer end surface of the convex portion 25. Can be applied directly. Thereby, since the heat generated inside the bearing can be easily radiated from the convex portion 25, the heat radiation performance of the bearing can be improved. As a result, since the temperature rise of the rolling bearing 20 can be suppressed, deterioration of the grease inside the rolling bearing can be suppressed, and the bearing life can be extended. Moreover, since the temperature rise of the boss | hub part 31 of the pulley part 30 can be suppressed, softening of the resin of the boss | hub part 31 can be suppressed. In addition, it is possible to suppress a decrease in the coupling force between the metal bearing outer ring and the resin pulley portion due to the difference in thermal expansion accompanying the temperature rise.

  Next, a second embodiment is shown in FIGS. The second embodiment differs from the first embodiment in that the convex portion 25 is formed so as to protrude in the axial direction from the axial end surface 21c of the outer ring 21. That is, a plurality of convex portions 25 extending in the axial direction are formed on the axial end surface 21c of the outer ring 21 of the rolling bearing 20 in the circumferential direction. The axial end portion of the convex portion 25 is the same as or extends from the axial end surface 31b of the boss portion 31, and a part of the convex portion 25 is exposed. That is, the axial front end surface of the convex portion 25 is viewed from the axial end surface 31b of the boss portion 31, or the axial front end portion of the convex portion 25 protrudes from the axial end surface 31b. The larger the surface area of the protruding portion of the protruding convex portion 25 in the axial direction is, the higher the heat radiation effect is.

  Even when the axial tip portion of the convex portion 25 is not exposed and the axial tip portion of the convex portion 25 is buried in the boss portion 31, the heat dissipation effect is low, but the convex portion 25 is higher than the uneven step of the knurling. By increasing the length in the axial direction, it is possible to obtain a higher creep prevention effect than the conventional knurling creep prevention mechanism. In addition, the axial direction length of the convex part 25 does not need to have the same both end surfaces.

  The second embodiment may be combined with the first embodiment. In this case, it is desirable that the protrusions 25 are exposed at all three positions in the radial direction and the axial direction. However, a heat dissipation effect can be obtained even if only one of these is exposed.

  Next, a third embodiment is shown in FIG. In the third embodiment, the convex portion 25 in the first embodiment, the second embodiment, and the combination thereof is not provided directly on the outer ring 21 of the rolling bearing 20, but a separate collar member 40 provided with the convex portion 25. Is press-fitted to the outer peripheral surface 21 b of the outer ring 21. The collar member 40 is made of steel, and can be integrated with the outer ring 21 by press-fitting to obtain the same effects as those of the first embodiment, the second embodiment, and combinations thereof.

  FIG. 4 shows the first embodiment as a representative. In the case of the second embodiment, only one end face in the axial direction can be provided on the collar member. However, by pressing a collar member having a half the axial width of the outer ring 21 from both axial sides, It is also possible to cope with an embodiment in which the convex portion 25 protrudes.

In addition, this invention is not limited to what was illustrated by said each embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.
For example, in the present embodiment, the case where the present invention is applied to a ball bearing is illustrated, but the present invention is not limited to this, and the present invention may be applied to other types of rolling bearings such as a cylindrical roller bearing and a tapered roller bearing. Good. Moreover, although this embodiment illustrated the case where it applies to a single row rolling bearing, it is not limited to this, You may apply this invention to a double row rolling bearing.
A plurality of V-shaped grooves may be formed on the rim portion 32 of the pulley portion 30 so that the V-belt is wound around the rim portion 32. Further, the reinforcing rib 34 of the pulley portion 30 may not be provided. In that case, there is no restriction | limiting in the circumferential direction position which the convex part 25 exposes.

DESCRIPTION OF SYMBOLS 10 Pulley apparatus 20 Rolling bearing 21 Outer ring 21a Outer ring raceway surface 21b Outer peripheral surface 21c Axial end surface 22 Inner ring 22a Inner ring raceway surface 25 Convex part 30 Pulley part 31 Boss part 31a Outer peripheral face 32 Rim part 33 Flange part 34 Reinforcement rib 40 Color member 40a Outer peripheral surface D1 Diameter of a virtual circle connecting the radial ends of a plurality of convex portions D2 Diameter of the outer peripheral surface of the boss portion D3 Diameter of the inner peripheral surface of the rim portion

Claims (5)

A rolling bearing, and a pulley portion made of synthetic resin formed on the outer peripheral surface of the rolling bearing,
The pulley portion includes a boss portion formed on an outer peripheral surface of the rolling bearing, a rim portion concentrically disposed on an outer diameter side of the boss portion, and a flange portion that connects the boss portion and the rim portion in a radial direction. And a pulley device comprising:
A plurality of convex portions extending in at least one of the three directions, either radially outward or axially, from the rolling bearing are formed at substantially equal intervals in the circumferential direction so that a wide surface faces in the circumferential direction. And
A pulley apparatus, wherein a part of the convex part is exposed from the boss part.   The pulley apparatus according to claim 1, wherein the convex portion is formed from an outer peripheral surface of the rolling bearing to an end surface in the axial direction.   When the diameter of a virtual circle connecting the radial tips of the convex portions is D1, the diameter of the outer peripheral surface of the boss portion is D2, and the diameter of the inner peripheral surface of the rim portion is D3, D2 ≦ D1 ≦ (D2 + D3) The pulley apparatus according to claim 1, wherein the pulley apparatus is / 2. The rolling bearing includes a cylindrical collar member fitted to the outer peripheral surface of the outer ring,
The pulley apparatus according to claim 1, wherein the convex portion is formed on the collar member.   The pulley apparatus according to claim 1, wherein the convex portion is formed on an outer ring of the rolling bearing.

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