JP3078201U - Auto tensioner and bearing shield material - Google Patents

Abstract

(57) [Problem] To improve the durability of a ball bearing by covering the ball bearing with a shield member. A pulley is rotatably mounted on a bearing portion of a swing arm via a ball bearing. The ball bearing 50 is covered from above by the first shield member 60 and is covered from below by the second shield member 80, whereby dust, water, salt water, and the like enter the annular holding chamber 53 which is a gap between the inner ring 52 and the outer ring 54. Prevent entry.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to an auto-tensioner used in a drive transmission system that transmits the driving force of an engine to each accessory by one endless belt in an automobile or the like, and particularly to a pulley mounting structure.

[0002]

[Prior art]

 In an auto tensioner, a swing arm is swingably attached to a fixed portion fixed at a predetermined position, and a pulley is attached to the tip of the swing arm in a rotating manner. The belt is hung on. The auto tensioner is provided with biasing means for pressing the pulley against the belt via the swing arm, and damping means for imparting swing resistance to the swing arm. The generated vibration is damped.

A ball bearing is provided between the bearing of the swing arm and the pulley to rotatably support the pulley. The ball bearing includes an outer ring and an inner ring which are two ring-shaped members arranged concentrically, and a plurality of rolling elements housed in an annular holding chamber which is a gap between the outer ring and the inner ring, and the inner ring has an arm bearing portion. In addition, the outer ring is integrally fixed to the pulley. In order for the rolling elements to rotate smoothly, it is necessary to hermetically seal the storage chambers opened at both ends in the axial direction to prevent dust or water. Various measures have been made to solve this problem.

Conventionally, a seal that seals the opening of the holding chamber is provided in the ball bearing itself, and a pan-shaped flange portion integral with the arm bearing portion is formed at both axial ends of the ball bearing. An annular shield member having a diameter approximately equal to the outer diameter of the outer ring is fixed to the swing arm, and the flange and the shield member cover both ends of the ball bearing to prevent dust, water, and salt water from entering the holding chamber. Had been prevented.

[0005]

[Problems to be solved by the invention]

 However, in order for the pulley to rotate smoothly without interfering with the swing arm, there must be a gap between the two. Specifically, the pulley is fixed to the flange of the swing arm and the pulley, or to the swing arm. A gap must be provided between the shield member and the pulley. Therefore, the dust and water resistance of the ball bearings are not sufficient, causing damage due to the ingress of dust into the holding chamber and the occurrence of rust due to the intrusion of water or salt water, which is a cause of deterioration of the ball bearing durability. Was.

[0006] The present invention has been made in view of the above problems, and has as its object to improve the durability of a ball bearing by improving the dustproof and waterproof functions of the ball bearing.

[0007]

[Means for Solving the Problems]

 The auto-tensioner of the present invention has an inner ring that is tightly fixed to the outer peripheral surface of the bearing provided on the swing arm, an outer ring that is tightly fixed to the inner peripheral surface of the pulley, and a ring that is a gap between the inner ring and the outer ring. A ball bearing having a rolling element housed in the holding chamber and rotatably supporting the pulley; an annular first shield member which covers the holding chamber from the swing arm side and is fixedly attached to the inner ring; And an annular second shield member that covers the holding chamber from the opposite side of the swing arm and is tightly fixed to the inner ring. As a result, the dust-proof and waterproof effect of the holding chamber is improved, and the durability of the ball bearing is improved.

The diameter of the annular second shield member is preferably larger than the diameter of the inner peripheral surface of the outer ring and smaller than the diameter of the outer peripheral surface of the outer ring. Thereby, the holding chamber is entirely covered in the radial direction. Further, the second shield member is preferably separated from the end face of the outer ring on the swing arm side, so that the rotation of the outer ring is not hindered.

Further, the shield member according to the present invention covers the ball bearing for rotatably fixing the pulley to the swing arm of the auto tensioner, and has an annular shape and holds the rolling element of the ball bearing. The holding chamber, which is a gap between the inner ring and the outer ring, is covered from the opposite side of the swing arm, and is tightly fixed to the end face of the inner ring on the swing arm side.

[0010]

[Embodiment of the invention]

 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a perspective view showing the auto-tensioner together with a belt, and a part of the auto-tensioner is shown broken. The auto-tensioner 10 has a cup 12 fixed to a predetermined position of an engine block (not shown), a swing shaft member 14 fixed to the center of the cup 12, and a rotatably mounted to the swing shaft member 14. A swing arm 16 and a pulley 18 attached to the tip of the swing arm 16 and relatively rotating about an axis L2 parallel to the swing axis L1 are provided. A belt 20 contacts the outer peripheral surface of the pulley 18.

The swing arm 16 is urged in a predetermined rotational direction by a torsion coil spring 22 housed in the cup 12, and the urge direction coincides with the direction in which the belt 20 is tightened. An annular damping member 24 made of a synthetic resin material is provided between the swing arm 16 and the cup opening 12a. The damping member 24 is fixed to the swing arm 16 and has two ring springs 26. Is pressed against the cup opening 12a.

When the belt 20 is driven, the pulley 18 relatively swings around the axis L2 and swings around the swing axis L1 within a certain angle range by the vibration generated in the belt 20. At this time, the swing arm 16 rotates around the swing axis L1 integrally with the pulley 18, and the damping member 24 slides on the cup opening 12a to apply frictional resistance to the swing arm 16. Thereby, the swing of the pulley 18, that is, the vibration of the belt 20 is attenuated.

FIG. 2 is a vertical cross-sectional view showing the configuration near the pulley in a partially enlarged manner. The swing arm 16 includes a cylindrical bearing portion 162 extending upward in the figure with the axis L2 as the axis. The pulley 18 is mounted on the outside of the bearing portion 162 via a ball bearing 50 so as to rotate. The pulley 18 is formed by integrally forming a cylindrical inner peripheral wall 182 and an outer peripheral wall 184 having an axis L2 as an axis and an annular wall 186 connecting these upper ends. The bearing portion 162 is inserted through.

The ball bearing 50 includes an inner ring 52 tightly fixed to an outer peripheral surface 162 a of the bearing portion 162, an outer ring 54 closely fixed to an inner peripheral surface 182 a of the pulley 18 (inner peripheral wall 182), and an inner ring 52 and an outer ring. And a plurality of rolling elements 56 housed in an annular holding chamber 53 which is a gap with the roller 54, and supports the pulley 18 rotatably around the axis L2. The holding chamber 53 has both ends opened in the direction of the axis L2, and these openings are closed by a seal (not shown).

The inner ring 52 is fixed in the direction of the axis L2. Specifically, the swing arm 16 includes a pedestal 164 having a diameter substantially equal to the outer diameter of the inner ring 52 on the base end side of the bearing portion 162. The lower end surface 52a of the inner ring 52 is supported from below by the pedestal 164. You. On the other hand, a bowl-shaped first shield member 60 is provided above the ball bearing 50 in the figure, and the first shield member 60 is tightly fixed to the upper end surface 52 b of the inner race 52 by bolts 70. The bolt 70 passes through the center hole 62 of the first shield member 60, and the male screw part 72 formed on the outer peripheral surface is screwed into the female screw part 162 b formed on the inner peripheral surface of the bearing part 162. As a result, it is attached to the swing arm 16. By the flange 74 of the bolt 70, the relative movement of the first shield member 60 and the inner ring 52 in the direction of the axis L2 is restricted.

The diameter of the first shield member 60 is set to a value smaller than the outer diameter of the outer ring 54 and larger than the inner diameter of the outer ring 54. That is, the gap between the inner ring 52 and the outer ring 54 is covered from above, thereby preventing foreign substances such as dust, water, and salt water from entering the gap from above. The outer edge 64 of the first shield member 60 is bent upward in the figure so as not to interfere with the outer ring 54 of the ball bearing 50, and is separated from the upper end surface 54b of the outer ring 54.

On the other hand, a second shield member 80 is provided below the ball bearing 50 in the figure, and the second shield member 80 is tightly attached to the lower end surface 52 a of the inner ring 52 by being sandwiched between the base 164 and the inner ring 52. It is fixed and the relative movement in the direction of the axis L2 is restricted. The diameter of the second shield member 80 is set to a value larger than the diameter of the inner peripheral surface of the outer ring 54 and smaller than the diameter of the outer peripheral surface of the outer ring 54, and covers the gap between the inner ring 52 and the outer ring 54 from below. This prevents foreign substances such as dust, water, and salt water from entering the gap from below.

FIG. 3 is a perspective view showing a state in which the second shield member 80 is cut in half vertically. The second shield member 80 is an annular plate member in which a hole 82 having a diameter slightly larger than the outer diameter of the bearing portion 162 is formed at the center, and is made of a material that can be easily processed, for example, a metal such as an aluminum alloy or a synthetic resin. It is formed. The outer edge 84 of the second shield member 80 is lowered one step downward in the figure so as not to interfere with the outer ring 54 of the ball bearing 50, and is separated from the lower end surface 54a of the outer ring 54 with a slight clearance. Thereby, the outer ring 54 can rotate relatively without contacting the second shield member 80. The lower corner 86 of the hole 82 is rounded in correspondence with the roundness 168 (FIG. 2) formed at the connecting portion between the bearing 162 and the base 164 facing each other.

The pulley 18 includes a flange 188 extending from the lower end of the inner peripheral wall 182 toward the pedestal 164 on the radially inner side. The flange 188 is located below the second shield member 80 in the direction of the axis L2, It extends at least to the axial center L2 side from the outer edge of the second shield member 80 in the radial direction. Further, a saucer-shaped flange 166 extending radially outward from the pedestal 164 of the swing arm 16 is located below the axis L2. As described above, the ball bearing 50, that is, the holding chamber 53 in the direction of the axis L2 is covered three times from below by the second shield member 80, the flange 188, and the flange 166, and the dustproof and waterproof function is improved.

[0021]

[Effect of the invention]

 As described above, the auto tensioner of the present invention is provided with a shield member to improve the dustproof and waterproof functions of the ball bearing, thereby improving the durability of the ball bearing.

[Brief description of the drawings]

FIG. 1 is a perspective view, partially cut away, of an embodiment of an auto tensioner of the present invention.

FIG. 2 is an enlarged view showing a configuration near a pulley in an arrow direction.

FIG. 3 is a perspective view showing a second shield member partially broken away.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Auto tensioner 16 Swing arm 162 Bearing 18 Pulley 50 Ball bearing 52 Inner ring 53 Holding chamber 54 Outer ring 56 Rolling element 60 First shield member 80 Second shield member

Claims (4)

[Utility model registration claims] 1. An inner ring closely fixed to an outer peripheral surface of a bearing portion provided on a swing arm, an outer ring tightly fixed to an inner peripheral surface of a pulley, and an annular ring which is a gap between the inner ring and the outer ring. A ball bearing having a rolling element housed in a holding chamber and rotatably supporting the pulley; and an annular first shield that covers the holding chamber from the swing arm side and is tightly fixed to the inner ring. An auto-tensioner, comprising: a member; and an annular second shield member that covers the holding chamber from the opposite side of the swing arm and is fixedly attached to the inner ring. 2. The auto tensioner according to claim 1, wherein a diameter of the second shield member is larger than a diameter of an inner peripheral surface of the outer ring and smaller than a diameter of an outer peripheral surface of the outer ring. 3. The auto-tensioner according to claim 1, wherein the second shield member is separated from an end surface of the outer race on the side of the swing arm. 4. A shield member for covering a ball bearing for rotatably fixing a pulley to a swing arm of an auto-tensioner, wherein the shield member has an annular shape and is provided between an inner ring and an outer ring for holding a rolling element of the ball bearing. A shield member for a bearing, wherein the annular holding chamber, which is a gap, is covered from the opposite side of the swing arm, and is tightly fixed to an end face of the inner ring on the swing arm side.