JP2008025666A - One-way clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the dilution of grease on the side of the inner ring of a one-way clutch. <P>SOLUTION: The one-way clutch comprises a plurality of sprags 3 arranged between an outer ring 1 and the inner ring 2 arranged coaxially with each other along the peripheral direction for engaging/disengaging the outer ring 1 with/from the inner ring 2, a cage 4 for holding the sprags 3, and an elastic member 5 for energizing the sprags 3 in the engaging direction, wherein contact portions between each engaging element 3 and each of the outer ring 1 and the inner ring 2 is lubricated by grease 6 filled between the outer ring 1 and the inner ring 2. Between the outer ring 1 and the inner ring 2, at least one roller 10 is arranged which has an axial center parallel to the axial direction of each of the inner and outer rings 2, 1. The roller 10 is constructed to rotate around the axial center with the rotation of the outer ring 1 or the inner ring 2. With the rotation of the roller 10, the rotating force moves the grease 6 from the side of the outer ring 1 to the side of the inner ring 2, therefore preventing the dilution of the grease 6 on the side of the inner ring 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a one-way clutch that transmits and shuts off rotational torque.

  In general, in an accessory drive device that transmits the rotation of a crankshaft of an engine of an automobile or the like to various accessories via a belt, the accessories such as a hydraulic pump of a power steering device and a compressor of an air conditioner, Alternatively, a one-way clutch is incorporated between a rotating shaft such as an alternator and a pulley provided on the rotating shaft.

  This one-way clutch couples the rotation shaft and pulley when the angular speed of rotation of the crankshaft increases and transmits the rotation of the crankshaft to the rotation shaft. When the angular speed decreases, the one-way clutch exceeds the one-way clutch. It functions to run and cut off the transmission of rotational torque from the crankshaft to the rotating shaft and prevent belt slippage.

As a one-way clutch employed in this type of accessory drive device, as shown in FIG. 4, a sprag type in which a number of “sprags” are incorporated in the space between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring. A one-way clutch is known (see, for example, Patent Document 1).
Also, a roller type that incorporates a number of "rollers" that engage with the circumferential cam surface formed on one of the inner and outer peripheral surfaces in the space between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring. A one-way clutch is also known (see, for example, Patent Document 2).
JP-A-2005-321022 JP 2006-138384 A

In a conventional one-way clutch, grease is filled between an outer ring and an inner ring. This grease is interposed in the contact portion between the engagement member such as the sprag and the roller, and the outer ring and the inner ring, and lubricates the contact portion.
However, when the inner and outer rings of the one-way clutch rotate at a high speed, the grease may move to the outer ring side due to the centrifugal force. If the grease moves to the outer ring side, the lubrication on the inner ring side becomes dilute, which may cause poor lubrication.

  Accordingly, an object of the present invention is to prevent the grease from becoming diluted on the inner ring side of the one-way clutch.

  In order to solve the above problems, the present invention has a rotatable roller disposed between the outer ring and the inner ring. If the roller rotates, the rotational force causes the grease to move from the outer ring side to the inner ring side, so that it is possible to prevent the grease from being diluted on the inner ring side.

  Specifically, the outer ring and the inner ring that are coaxially arranged and relatively rotatable about the axis are arranged along the circumferential direction between the outer ring and the inner ring, and the outer ring and the inner ring are relatively relative to each other in one direction. A plurality of engagement elements that are engaged with the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring when rotated to couple both wheels and are rotated relative to each other in the other direction, and holding that holds the engagement elements And an elastic member that urges each of the engaging elements in a direction to engage with the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, and each of the engaging elements is filled with grease filled between the outer ring and the inner ring. In the one-way clutch adapted to lubricate the contact portion between the outer ring and the inner ring, at least one cylindrical roller having an axis parallel to the axial direction of the inner and outer rings is disposed between the outer ring and the inner ring. The roller is rotatable about the axis. It adopted the clutch.

For example, a configuration in which the driving force is transmitted to the roller and the roller rotates about its own axis independently of the rotation of the outer ring or the inner ring can be considered. The roller can rotate around the axis. For example, when the outer peripheral surface of the roller is in contact with the inner peripheral surface of the outer ring or the outer peripheral surface of the inner ring, the rotational force is transmitted to the roller by the frictional force, or the flow of grease accompanying the rotation of the outer ring or the inner ring A configuration in which the rotational force is transmitted to the roller via the roller can be adopted.
In addition, if the said roller is hold | maintained in the circumferential direction with a holder | retainer, interference with an adjacent engaging element can be excluded.

In the above configuration, a configuration in which a plurality of recesses are formed on the surface of the roller can be employed. If the concave portion is formed on the surface of the roller, the grease easily adheres to the surface of the roller, so that the grease can be held more efficiently on the outer ring side, and the held grease can be moved to the inner ring side.
In addition, although the said recessed part may employ | adopt free planar shape and cross-sectional shape, for example, if the bottom part is formed in the dimple shape which used the arc-shaped surface, since the retention power (adhesion force) of grease improves further, it is desirable.

  Further, in the above configuration, a groove extending along the axial direction of the roller, a groove extending in the circumferential direction of the roller, or a groove extending spirally around the axis of the roller is formed on the surface of the roller. A configuration may be employed.

If a groove extending along the axial direction of the roller is formed on the surface of the roller, the side wall along the length direction of the groove should move the grease (direction from the outer ring side toward the inner ring side). Orthogonal to Since the grease hits the wall surface of the groove, the holding force for moving the grease in the circumferential direction along the surface of the roller can be further increased.
The groove in the axial direction may be provided over the entire length of the roller or a part thereof. If the axial grooves are provided in parallel in a plurality of rows, the effect is further enhanced.

Further, if a groove extending in the circumferential direction of the roller is formed on the surface of the roller, there is an effect that the grease easily enters the groove.
If the surface of the roller has a groove extending spirally around the axis of the roller, the effects of both the axial groove and the circumferential groove can be expected.

  In addition, although the said groove | channel of an axial center direction, the groove | channel of the circumferential direction, and a helical groove | channel may each be employ | adopted independently, you may selectively employ | adopt the groove | channel of a some form from the above. Moreover, you may use together the groove | channel of all the forms. Furthermore, the structure which provided the said recessed part between adjacent groove | channels is also employable.

  In the present invention, since a rotatable roller is disposed between the outer ring and the inner ring of the one-way clutch, the grease is moved from the outer ring side to the inner ring side by the rotational force of the roller so that the grease is not diluted on the inner ring side. Can be.

  Further, since the recess or groove is formed on the surface of the roller, the grease can be efficiently moved from the outer ring side to the inner ring side.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a pulley with a built-in clutch in which a one-way clutch is incorporated in a pulley 7.
The one-way clutch includes an outer ring 1 that is press-fitted into an inner diameter surface of a pulley 7, an inner ring 2 that is coaxially incorporated inside the outer ring 1, and a sprag (engagement element) that is incorporated between the inner and outer wheels 1 and 2. 3, a retainer 4 that holds the sprag 3, and a coil spring (elastic member) 5 that biases the sprag 3 in the engaging direction.

  The outer ring 1 has a shorter axial length than the inner ring 2, and an inner peripheral cylindrical surface (inner peripheral surface) 1 a is formed on the inner periphery of the outer ring 1.

  On the outer periphery of the inner ring 2, an outer peripheral cylindrical surface (outer peripheral surface) 2a that is opposed to the inner peripheral cylindrical surface 1a of the outer ring 1 in the radial direction is formed. Further, on the outer periphery of the inner ring 2, bearing fitting surfaces 2b, 2b having a slightly smaller diameter than the outer cylindrical surface 2a are formed on both axial sides of the outer cylindrical surface 2a. The bearing part 8 is supported by this.

  The bearing part 8 consists of a ball bearing with a single seal. The bearing portion 8 is assembled so that the seal 8c is positioned on the outer side in the axial direction, and the outer ring 1 and the inner ring 2 integral with the pulley 7 are relatively rotated around the axis by the pair of bearings 8a and 8b and the ball 9. It is supposed to be rotatable. Grease 6 is sealed in the space between the outer ring 1 and the inner ring 2 between the bearing portions 8 provided on both sides in the axial direction.

  The sprags 3 are arranged at equal intervals in the circumferential direction between the inner peripheral cylindrical surface 1 a of the outer ring 1 and the outer peripheral cylindrical surface 2 a of the inner ring 2.

A cage 4 is provided between the inner peripheral cylindrical surface 1a of the outer ring 1 and the outer peripheral cylindrical surface 2a of the inner ring 2 for positioning the sprags 3 in the circumferential direction. The cage 4 is made of a synthetic resin molded product, and is formed with a plurality of pockets 4a for individually accommodating the sprags 3 and spring accommodating recesses 4b communicating with the pockets 4a (see FIG. 1 (a)). ).
The coil spring 5 is incorporated in each spring accommodating recess 4b, and the cam spring formed on each sprag 3 is engaged with the inner peripheral cylindrical surface 1a of the outer ring 1 and the outer peripheral cylindrical surface 2a of the inner ring 2. The sprags 3 are urged in the direction of alignment.
As shown in FIG. 4 of the conventional example, the cage 4 has a configuration in which the ball 9 of one bearing portion 8 in the axial direction is held by the cage 4.

Here, in this pulley with a built-in clutch, the outer ring 1 provided with the pulley 7 is on the driving side and the inner ring 2 is on the driven side, and each sprag 3 has the pulley 7 together with the outer ring 1 with respect to the inner ring 2 as shown in FIG. When relative rotation is performed in the direction of the arrow shown in a), the inner and outer cylindrical surfaces 1a and 2a are engaged to transmit the rotational torque of the outer ring 1 to the inner ring 2.
Each sprag 3 rotates relative to the inner ring 2 in the opposite direction indicated by the arrow, or the rotational speed of the inner ring 2 that rotates in the same direction with respect to the outer ring 1 that rotates in the arrow direction. When the rotational speed of the outer ring 1 exceeds the rotational speed of the outer ring 1, the engagement with the inner and outer cylindrical surfaces 1 a and 2 a is released, and the rotation transmission from the outer ring 1 to the inner ring 2 is cut off.

Therefore, as shown in FIG. 2, when the pulley 7 (outer ring 1) is rotated in the direction of arrow f2, the sprag 3 changes its posture in the direction indicated by the chain line in the figure (see arrow s1), and each cam of the sprag 3 The surface engages with the inner peripheral cylindrical surface 1 a of the outer ring 1 and the outer peripheral cylindrical surface 2 a of the inner ring 2. By this engagement, the rotation of the pulley 7 is transmitted to the inner ring 2.
When the rotation speed of the inner ring 2 exceeds the rotation speed of the outer ring 1, the pulley 7 rotates relative to the inner ring 2 in the direction of the arrow f1 in the figure, so that the sprag 3 changes its posture in the opposite direction (see arrow s2). The sprag 3 is disengaged from the inner and outer cylindrical surfaces 1a and 2a, and the rotation transmission from the outer ring 1 to the inner ring 2 is interrupted.

For this reason, if such a pulley with a built-in clutch is attached to the rotating shaft of the alternator and the alternator is driven by driving a belt between the pulley attached to the crankshaft and the pulley on the rotating shaft, the angular speed of the crankshaft increases. At this time, the one-way clutch is engaged, and the rotation of the crankshaft is transmitted to the rotating shaft of the alternator. Further, when the angular velocity of the crankshaft is reduced, the one-way clutch is idling, and the rotation transmission from the crankshaft to the rotating shaft of the alternator is interrupted.
For this reason, it is possible to prevent slippage between the pulley 7 and the belt applied thereto, and to suppress wear of the belt.

  Here, with the rotation of the outer ring 1 or the inner ring 2 of the one-way clutch, a centrifugal force acts on the grease 6 enclosed between the bearing parts 8 and 8. Due to this centrifugal force, the grease 6 tends to be gradually distributed radially outward. That is, the grease 6 is unevenly distributed on the outer ring 1 side, and the grease 6 on the inner ring 2 side is diluted.

At this time, a metal roller 10 having an axis parallel to the axial direction of the one-way clutch is disposed between the outer ring 1 and the inner ring 2. The roller 10 is formed in a columnar shape, and its diameter is set to be substantially the same as the distance between the inner and outer cylindrical surfaces 1a and 2a.
The roller 10 is housed in the pocket 4a of the retainer 4 and positioned in the circumferential direction of the one-way clutch, and is rotatable around the axis at that position. Further, the roller 10 is restricted from moving in the axial direction by a known method while being allowed to rotate around its axis.

When the outer peripheral cylindrical surface 10a of the roller 10 is in contact with the inner peripheral cylindrical surface 1a of the outer ring 1 and the outer peripheral cylindrical surface 2a of the inner ring 2, the opposing surfaces 10a, 1a and 10a, 2a slide against each other, and the friction force Thus, the rotational force is transmitted to the roller 10.
As the roller 10 rotates, the grease 6 moves from the outer ring 1 side to the inner ring 2 side as indicated by an arrow in FIG. For this reason, it is possible to prevent the grease 6 from being diluted on the inner ring 2 side.

  In addition, since a large number of dimple-shaped recesses 11 whose bottom surface is an arc surface is formed on the cylindrical surface (front surface) 10a of the roller 10 (see FIGS. 3A and 3B), the grease 6 has the recess 11 This is advantageous in that the roller 10 is easily held along with the rotation. Further, if the concave portion 11 is in a dimple shape, there is an effect that when the grease 6 adheres to the outer peripheral cylindrical surface 2a of the inner ring 2 on the inner ring 2 side, it is easily detached from the cylindrical surface 10a of the roller 10.

  As another embodiment, grooves 12, 13, and 14 having various shapes may be formed instead of the recesses 11 formed in the cylindrical surface 10 a of the roller 10. FIG. 3C shows a mode in which a groove 12 extending in the axial direction is formed on the cylindrical surface 10 a of the roller 10. FIG. 3D shows a mode in which grooves 13 extending in the circumferential direction are formed on the cylindrical surface 10 a of the roller 10. Further, FIG. 3E shows a mode in which a spiral groove 14 is formed on the cylindrical surface 10 a of the roller 10. Any of the grooves 12, 13, and 14 has a function capable of efficiently moving the grease 6 from the outer ring 1 side to the inner ring 2 side.

  Furthermore, as another embodiment, the cylindrical surface 10a of the roller 10 is in contact with either the inner peripheral cylindrical surface 1a of the outer ring 1 or the outer peripheral cylindrical surface 2a of the inner ring 2, and the rotational force is applied. Alternatively, the cylindrical surface 10a of the roller 10 is not in contact with both the cylindrical surfaces 1a and 2a, and the roller 10 is flowed through the circumferential flow of the grease 6 as the outer ring 1 or the inner ring 2 rotates. Alternatively, a configuration in which the rotational force is transmitted may be adopted.

  Moreover, although the space | interval of the sprags 3 and 3 adjacent to the roller 10 may be set freely, in the said embodiment, the space | interval is set to be the same as the space | interval between the above-mentioned adjacent sprags 3 and 3. FIG. For this reason, the retainer 4 can use the conventional product which does not provide the roller 10.

The material of the roller 10 may be the same metal material as the sprag 3, but may be a synthetic resin material.
Moreover, in this embodiment, although the roller 10 was arrange | positioned in two places along the circumferential direction, the number which arrange | positions the roller 10 can be set freely.

This embodiment is a pulley with a built-in clutch incorporating a one-way clutch. The outer ring 1 is a driving side and the inner ring 2 is a driven side. However, as another embodiment, the inner ring 2 is a driving side and the outer ring 1 is a driven side. It can also be applied to one-way clutches for various applications.
In the above embodiment, a sprag type one-way clutch in which the engagement element 3 is formed of a sprag is shown as the one-way clutch, but the one-way clutch is not limited to this. For example, the present invention can be applied to a roller type one-way clutch in which the engagement element 3 is composed of rollers (rollers).

1 shows an embodiment, (a) is a cut side view, (b) is a cut front view. Enlarged view of the main part showing the action of sprags The details of the roller are shown, (a) and (b) are embodiments in which dimple-shaped recesses are formed on the surface, (c) is an embodiment in which grooves extending in the axial direction are formed on the surface, and (d) is a surface in the circumferential direction. The aspect which formed the groove | channel which extends, (e) is each perspective view which shows the aspect which formed the helical groove | channel on the surface A conventional example is shown, (a) is a cut side view, (b) is a cut front view.

Explanation of symbols

1 Outer ring 2 Inner ring 3 Sprag (engagement element)
4 Cage 4a Pocket 4b Spring accommodating recess 5 Coil spring (elastic member)
6 Grease 7 Pulley 8 Bearing portion 8a, 8b Bearing 8c Seal 9 Ball 10 Roller 10a Surface 11 Recess 12, 13, 14 Groove

Claims (6)

The outer ring 1 and the inner ring 2 that are coaxially arranged and relatively rotatable about the axis, and are arranged along the circumferential direction between the outer ring 1 and the inner ring 2, and the outer ring 1 and the inner ring 2 are relatively relative to each other in one direction. A plurality of engagement elements 3 that are engaged with the inner peripheral surface 1a of the outer ring 1 and the outer peripheral surface 2a of the inner ring 2 by rotating to connect the two wheels 1 and 2 and are rotated relative to each other in the other direction; A retainer 4 for holding the engagement elements 3; and an elastic member 5 for urging the engagement elements 3 in a direction to engage the inner peripheral surface 1a of the outer ring 1 and the outer peripheral surface 2a of the inner ring 2. In the one-way clutch in which the contact portion between each of the engagement elements 3 and the outer ring 1 and the inner ring 2 is lubricated by the grease 6 filled between the outer ring 1 and the inner ring 2;
At least one roller 10 having an axis parallel to the axial direction of the inner and outer rings 2 and 1 is disposed between the outer ring 1 and the inner ring 2, and the roller 10 is rotatable around the axis. One-way clutch characterized by   The one-way clutch characterized in that the roller 10 rotates around the axis as the outer ring 1 or the inner ring 2 rotates.   The one-way clutch according to claim 1, wherein a plurality of recesses 11 are formed on the surface of the roller 10.   The one-way clutch according to any one of claims 1 to 3, wherein a groove 12 extending along the axial center direction of the roller 10 is formed on the surface of the roller 10.   The one-way clutch according to claim 1, wherein a groove 13 extending in a circumferential direction of the roller 10 is formed on a surface of the roller 10.   The one-way clutch according to any one of claims 1 to 5, wherein a groove 14 extending spirally around the axis of the roller 10 is formed on the surface of the roller 10.

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