JP2009287608A - Turn energizing mechanism and pulley device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turn energizing mechanism capable of effectively reducing a rotating speed fluctuation between an outside member and an inside member. <P>SOLUTION: The turn energizing mechanism 1 comprises the outside member 2 having an outside raceway surface 21 on the inner periphery and rotatable around a first axis X1, the inside member 3 having an inside raceway surface 31 on the outer periphery, which is arranged on the radial inside of the outside raceway surface 21, and rotatable around the first axis X1, and balls 4 rollingly arranged between the outside raceway surface 21 and the inside raceway surface 31. The outside raceway surface 21 is formed around a second axis X2 inclined to the first axis X1, and the inside raceway surface 31 is formed around a third axis X3 corresponding to the first axis X1 and arranged crossing the outside raceway surface 21. The balls 4 are arranged in a crossing area between the outside raceway surface 21 and the inside raceway surface 31. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotation urging mechanism having spring elasticity in the rotation direction, and a pulley apparatus including the rotation urging mechanism.

  An alternator used as an auxiliary machine for an engine of an automobile or the like is driven by a rotational force extracted from a crankshaft and supplies electric power necessary for running the automobile. An alternator pulley device is attached to the input shaft of the alternator, and the rotational force of the engine is applied to the alternator by spanning a belt between the alternator pulley device and a pulley attached to the crankshaft. Communicating.

  In general, a crankshaft of an engine such as an automobile is given a rotational force by an explosive force in a cylinder, so that the rotational speed fluctuates. On the other hand, in the alternator, a relatively heavy armature or the like is rotating integrally with the input shaft, and if the fluctuation of the rotation speed of the crankshaft is abrupt, the armature is caused by an inertial force generated by its own rotation. In some cases, it is not possible to follow fluctuations in the rotational speed of the crankshaft.

  If the alternator cannot follow the fluctuations in the rotational speed, there will be a temporary difference between the rotational speed of the crankshaft and the alternator, causing slip between the alternator pulley device and the belt, The tension of the arm may fluctuate excessively. Such excessive belt slip and tension fluctuations may cause abnormal noise of the belt and shorten the life. In addition, in order to prevent the belt from slipping, the initial tension of the belt may be set relatively high. In this case, the rotational resistance of the crankshaft increases and the fuel efficiency performance of the engine may be lowered. .

  For this reason, in a conventional pulley device for an alternator, a pulley member around which a belt is wound and an input shaft of the alternator are fixed so as to be integrally rotatable in order to allow fluctuations in the rotational speed transmitted from the crankshaft. A rotation urging mechanism is provided between the pulley bosses.

  As this rotation urging mechanism, in Patent Document 1, a torsion coil spring is provided between a pulley member and a pulley boss, and the pulley member and the pulley boss are temporarily moved by an elastic force generated by twisting the torsion coil spring. A technique is disclosed in which fluctuations in rotational speed are alleviated by elastically rotating relative to each other in the circumferential direction.

Japanese Patent Laid-Open No. 5-180287

In the rotation urging mechanism of Patent Document 1, the rotational fluctuation relaxation characteristic of the pulley member with respect to the pulley boss depends on the torsion coil spring, and this torsion coil spring is large enough to be incorporated into the alternator pulley device. Therefore, the wire diameter, the free length, the number of windings, etc. are limited, and the characteristics of the torsion coil spring cannot be set freely. Further, the spring constant of the torsion coil spring is constant, and the spring constant cannot be freely changed according to the torsion angle. For this reason, the freedom degree at the time of setting the rotation fluctuation relaxation characteristic as the pulley device for an alternator is limited, and there is a possibility that the rotation speed fluctuation of the crankshaft cannot be sufficiently reduced. In addition, the provision of the coil spring reduces the strength of the pulley device, which is disadvantageous in terms of durability.
The present invention has been made in view of such circumstances, and a rotation urging mechanism capable of more effectively mitigating fluctuations in rotational speed between an outer member such as a pulley member and an inner member such as a pulley boss, and the like. An object is to provide a pulley device.

  The rotation urging mechanism of the present invention has an outer raceway surface on the inner circumference, an outer member rotatable around a first axis, and an inner raceway surface arranged radially inside the outer raceway surface. And an inner member rotatable around the first axis, and a ball arranged to roll between the outer raceway surface and the inner raceway surface, and the outer raceway surface And the inner raceway surface is formed around a second axis inclined with respect to the first axis, and the other raceway surface is inclined with respect to the second axis. It is formed around an axis and is disposed so as to intersect with the one track surface, and the balls are disposed at the intersection of the outer track surface and the inner track surface.

  Further, the pulley device of the present invention includes a pulley member around which a belt is wound, a shaft body disposed concentrically with the pulley member on an inner peripheral side of the pulley member, the pulley member and the shaft body, A rotation biasing mechanism disposed between the outer raceway surface provided on the inner circumferential side of the pulley member and the outer circumferential side of the shaft body. An inner raceway surface arranged radially inward of the outer raceway surface, and a ball arranged to roll between the outer raceway surface and the inner raceway surface, and the outer raceway surface and the One of the inner raceways is formed around a second axis inclined with respect to the rotational axis of the pulley member, and the other raceway is inclined with respect to the second axis. Formed around an axis and disposed so as to intersect the one raceway surface, Serial balls, characterized in that it is arranged on the outer raceway surface and cross section of the inner raceway surface.

  According to the above rotation urging mechanism and the pulley device, for example, when the outer member (pulley member) rotates around the first axis (the rotation axis of the pulley member) relative to the inner member (shaft body), this Along with the outer raceway surface, the ball rolls to a position shifted in the circumferential direction from the intersection of the outer raceway surface and the inner raceway surface. At a position shifted in the circumferential direction from the intersection, the radial distance between the outer raceway surface and the inner raceway surface gradually narrows in a wedge shape, and balls enter the wedge-shaped space, so that the outer raceway surface and the inner raceway surface become inward. A ball is gradually pinched between the raceway surface. By this action, an elastic force (rotating biasing force) is generated in a direction that relaxes the relative rotation between the outer raceway surface and the inner raceway surface. When the relative rotation angle between the outer raceway surface and the inner raceway surface reaches a predetermined value, the relative rotation between the outer raceway surface and the inner raceway surface is restricted by the balls, and the outer member and the inner member rotate integrally.

Therefore, in the present invention, it is possible to elastically absorb (relax) rotational fluctuations between the outer member and the inner member within a range in which the outer raceway surface and the inner raceway surface can be rotated relative to each other. The rotational fluctuation mitigation characteristics can be freely set by changing the curvature radius of the outer raceway surface and the inner raceway surface, the diameter of the ball, etc., and the rotational fluctuation can be effectively mitigated.
Further, unlike the prior art, it is not necessary to have a complicated structure for providing a torsion coil spring or a torsion coil spring, and it is possible to form a rotation urging mechanism with a very simple structure. The mechanism can also be reduced in size. In addition, the outer member and the inner member can be formed with the outer raceway surface and the inner raceway surface around the second and third axes by substantially the same method as the processing of the raceway surface of a general rolling bearing. It is easy to manufacture.
In addition, the rotation urging mechanism of the present invention has a form like a rolling bearing by the outer member, the inner member, and the balls, and can have a structure capable of supporting a radial load acting on the outer member and the inner member.

  It is preferable that the third axis coincides with the first axis. Thereby, the other raceway surface can be processed by the same method as the method of processing the raceway surface of the rolling bearing, and the workability can be further improved.

  According to the present invention, fluctuations in rotational speed between the outer member and the inner member can be more effectively mitigated.

  1 is a cross-sectional view of a rotation urging mechanism 1 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA of FIG. The rotation urging mechanism 1 includes an annular outer ring (outer member) 2 having an outer raceway surface 21 on the inner periphery, an annular inner ring (inner member) 3 having an inner raceway surface 31 on the outer periphery, and an outer raceway surface 21. And a plurality of balls 4 arranged between the inner raceway surfaces 31. The outer ring 2, the inner ring 3, and the ball 4 are made of metal such as bearing steel. The outer ring 2 and the inner ring 3 are rotatable around the first axis X1. The outer raceway surface 21 and the inner raceway surface 31 are formed in a concave arc shape (concave curved surface shape) as a cross-section cut by a plane passing through the first axis X1, and the curvature radius thereof is larger than the radius of the ball 4. Yes.

  As shown in FIG. 1, the outer raceway surface 21 is formed around the second axis X2 inclined with respect to the first axis X1. In other words, the outer raceway surface 21 is formed in parallel to the surface Y2 inclined with respect to the vertical surface Y1 orthogonal to the first axis X1. The inner raceway surface 31 is formed around a third axis X3 that coincides with the first axis X1. In other words, the inner raceway surface 31 is formed in parallel with the vertical surfaces Y1 and Y3 orthogonal to the first and third axes X1 and X3. Therefore, the third axis X3 of the inner raceway surface 31 is inclined with respect to the second axis X2 of the outer raceway surface 21.

  In FIG. 2, the outer raceway surface 21 and the inner raceway surface 31 intersect at two upper and lower locations, and balls 4 are disposed at each intersection. For example, when the inner ring 3 is stopped and the outer ring 2 is rotated around the first axis X1, the ball 4 moves in the circumferential direction as the outer raceway surface 21 moves. Hereinafter, the operation at this time will be described in detail with reference to FIG.

  FIG. 3A is a schematic front view for explaining the operation of the rotation urging mechanism, and FIG. 3B is a schematic cross-sectional view corresponding to the arrow BB in FIG. 3A and 3B, when the outer raceway surface 21 rotates in the arrow direction C with respect to the inner raceway surface 31, the balls 4 move in the circumferential direction as indicated by the arrow D along with the outer raceway surface 21. To do. At this time, the radial distance between the outer raceway surface 21 and the inner raceway surface 31 gradually decreases in a wedge shape at a position shifted in the circumferential direction from the intersection center O between the outer raceway surface 21 and the inner raceway surface 31. Therefore (see FIG. 3B), the balls 4 are gradually strongly sandwiched between the outer raceway surface 21 and the inner raceway surface 31, and the relative rotation between the outer raceway surface 21 and the inner raceway surface 31 is restricted. As a result, the inner raceway surface 31 rotates integrally with the outer raceway surface 21. When the outer ring raceway surface 21 rotates in the reverse direction (indicated by a dotted arrow), the ball 4 rolls in the reverse direction (indicated by a dotted arrow) and acts in the same manner as described above.

  In the process in which the outer raceway surface 21 and the inner raceway surface 31 rotate relative to each other, the contact pressure between the balls 4 and the outer raceway surface 21 and the inner raceway surface 31 is gradually increased. And the direction (relative rotation) which relieves the relative rotation of the outer raceway surface 21 and the inner raceway surface 31 by elastic deformation of the ball 4 and the raceway surfaces 21 and 31 accompanying the contact between the ball 4 and the raceway surfaces 21 and 31. A rotational biasing force (torsion spring force) in the direction opposite to the direction is generated. Further, the spring constant of the rotation urging mechanism 1 gradually increases as the amount of relative movement in the axial direction between the outer raceway surface 21 and the inner raceway surface 31 increases, and the rotation urging force also increases accordingly. .

In the above configuration, when the outer ring 2 and the inner ring 3 can be rotated relative to each other within a predetermined range, and the outer ring 2 and the inner ring 3 are rotating together, the rotational fluctuation occurs between the two and the third part. It is possible to elastically absorb (relax) rotational fluctuations in the relative rotational range.
Further, the rotational fluctuation mitigation characteristics can be freely set by changing the curvature radius and groove depth of the outer raceway surface 21 and the inner raceway surface 31, the radius of the ball 4, the crossing angle of the outer raceway surface 21 and the inner raceway surface 31, and the like. Can be set to For example, if the radius of curvature of the outer raceway surface 21 and the inner raceway surface 31 is increased, the relative rotation range of the outer raceway surface 21 and the inner raceway surface 31 is also increased, and the spring constant (spring stiffness) of the rotation biasing mechanism 1 is increased. It can be set low. Therefore, it is possible to effectively mitigate rotational fluctuations between the outer member 2 and the inner member 3 according to the rotational characteristics of the outer ring 2 and the inner ring 3.

  Further, the torsion coil spring and the complicated structure for providing the torsion coil spring as in the prior art are not required, and the outer raceway surface and the inner raceway surface are formed on the outer member and the inner member, and between the raceway surfaces. The rotation urging mechanism 1 can be formed with a simple structure in which balls are arranged, and the rotation urging mechanism 1 can be downsized. Further, since the outer raceway surface 21 and the inner raceway surface 31 are formed as uniform grooves in the circumferential direction around the second and third axes X2 and X3, a method for processing the raceway surface of a general rolling bearing (polishing) The outer raceway surface 21 and the inner raceway surface 31 can be formed by substantially the same method as the method (method), and manufacture (processing) is facilitated. Further, the rotation urging mechanism 1 is configured like a rolling bearing by the outer member 2, the inner member 3, and the balls 4, so that the radial load acting on the outer ring 2 and the inner ring 3 can be supported.

Hereinafter, application examples of the rotation urging mechanism 1 of the present invention will be described.
FIG. 4 is a cross-sectional view of the pulley device 7 provided with the rotation urging mechanism 1 of the present invention. The pulley device 7 is used by being attached to an input shaft 8 of an alternator used as an engine auxiliary machine such as an automobile. The pulley device 7 includes a pulley boss (shaft body) 71 formed in a cylindrical shape, a cylindrical pulley member 72 disposed coaxially on the outer peripheral side of the pulley boss 71, and two rolling members interposed therebetween. And a bearing 73. A rotation urging mechanism 1 is provided between the two rolling bearings 73.

A wave-like groove is formed on the outer peripheral surface 72A of the pulley member 72, and the belt 9 for transmitting the rotational force from the crankshaft of the engine is wound around the outer peripheral surface 72A.
An input shaft 8 protruding from an alternator (not shown) is inserted into the inner periphery of the pulley boss 71. Further, an internal thread portion 71A is integrally formed in the axially intermediate portion of the pulley boss 71, and the external thread portion 8A provided at the end of the input shaft 8 is screwed into the internal thread portion 71A. Thus, the pulley boss 71 is connected to the input shaft 8 so as to be rotatable together. Further, a regular hexagonal wrench insertion portion 71 </ b> B for inserting a hexagon wrench for screwing the pulley boss 71 to the input shaft 8 is formed at the inner peripheral end of the pulley boss 71.
The rolling bearing 73 enables the pulley boss 71 and the pulley member 72 to rotate relative to each other and supports a radial load acting on the pulley member 72.

  The rotation urging mechanism 1 includes a pulley member 72 as an outer member (outer ring), a pulley boss 71 as an inner member (inner ring), and a ball 4. An outer raceway surface 721 is formed on the inner circumferential surface of the pulley member 72, an inner raceway surface 711 is formed on the outer circumferential surface of the pulley boss 71, and a plurality (two pieces) are provided between the outer raceway surface 721 and the inner raceway surface 711. Balls 4 are arranged. These detailed configurations are as described with reference to FIGS. The outer raceway surface 721 and the inner raceway surface 711 do not have to be directly formed on the pulley member 72 or the pulley boss 71, and are fixed to the outer member fixed to the inner peripheral surface of the pulley member 72 or the outer peripheral surface of the pulley boss 71. The inner member may be formed.

  In this embodiment, when the pulley member 72 is rotated by the rotational power transmitted from the crankshaft of the engine via the belt 9, the outer raceway surface 721 moves relative to the inner raceway surface 711 in the circumferential direction and is axially moved. Also move relative. As described with reference to FIG. 3, the ball 4 is strongly sandwiched between the outer raceway surface 721 and the inner raceway surface 711, thereby restricting relative movement between the outer raceway surface 721 and the inner raceway surface 711. Then, the pulley boss 71 rotates together with the pulley member 72, and the input shaft 8 of the alternator rotates.

  When a rotational variation occurs between the pulley member 72 and the pulley boss 71 due to a rotational variation of the crankshaft, the rotational variation can be elastically reduced by the relative rotation of the pulley member 72 and the pulley boss 71. And the slip which arises between the belt 9 and the pulley member 72 can be suppressed effectively by relieving the fluctuation | variation of the rotational speed of a crankshaft. Therefore, it is possible to set the initial tension of the belt 9 low, thereby reducing the load on the crankshaft and improving the fuel efficiency of the engine.

The present invention is not limited to the above-described embodiment, and can be appropriately changed in design. For example, the second axis X2 of the outer raceway surfaces 21 and 721 and the first axis X1 may coincide with each other, and the third axis X3 of the inner raceway surfaces 31 and 711 may be inclined with respect to the first axis X1. Good. Further, both the second and third axis X2 and X3 can be inclined with respect to the first axis X1.
The outer raceway surface 21 and the inner raceway surface 31 may have the same radius of curvature or groove depth or different dimensions. Whether the radius of curvature and the groove depth are the same or different can be appropriately designed according to the rotational characteristics of the outer member 2 and the inner member 3. Further, the number of trajectory rows of the balls 4 is not limited to one row, and may be double rows such as 2 rows and 3 rows according to the load.

  The rotation urging mechanism of the present invention can be applied to, for example, a crank pulley, a pulley for a car air conditioner, an auto tensioner, and the like in addition to a pulley device for an alternator. It can also be used for a clutch disk of a clutch. Further, it can be used as a torque sensor by attaching an angle sensor that can measure the rotation angle between the inner and outer rings.

It is sectional drawing of the rotation urging | biasing mechanism in embodiment of this invention. It is AA arrow sectional drawing of FIG. (A) is a schematic front view for demonstrating the effect | action of a rotation biasing mechanism, (b) is a schematic sectional drawing corresponded to the BB arrow of (a). It is sectional drawing of the pulley apparatus to which the rotation urging mechanism is applied.

Explanation of symbols

1 Rotating biasing mechanism 2 Outer ring (outer member)
21 Outer raceway surface 3 Inner ring (inner member)
31 Inner raceway surface 4 Ball 7 Pulley device 71 Pulley boss (shaft body)
72 Pulley member 9 Belt

Claims (3)

An outer member having an outer raceway surface on the inner periphery and rotatable about a first axis;
An inner member arranged on the outer periphery of the outer raceway surface on the radially inner side and rotatable about the first axis; and
A ball disposed so as to roll between the outer raceway surface and the inner raceway surface,
Any one of the outer raceway surface and the inner raceway surface is formed around a second axis inclined with respect to the first axis, and the other raceway is formed with respect to the second axis. Formed around the inclined third axis and disposed so as to intersect the one track surface;
The rotation urging mechanism characterized in that the balls are arranged at intersections of the outer raceway surface and the inner raceway surface.   The rotation urging mechanism according to claim 1, wherein the third axis coincides with the first axis. A pulley member around which a belt is wound;
On the inner peripheral side of this pulley member, a shaft body arranged concentrically with the pulley member,
A rotation biasing mechanism disposed between the pulley member and the shaft body,
The rotation biasing mechanism is
An outer raceway surface provided on the inner peripheral side of the pulley member;
An inner raceway surface disposed radially inward of the outer raceway surface on the outer peripheral side of the shaft body;
A ball disposed so as to roll between the outer raceway surface and the inner raceway surface,
One of the outer raceway surface and the inner raceway surface is formed around a second axis inclined with respect to the rotation axis of the pulley member,
The other raceway surface is formed around a third axis inclined with respect to the second axis and is disposed so as to intersect the one raceway;
The pulley apparatus, wherein the balls are arranged at an intersection of the outer raceway surface and the inner raceway surface.

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