JP2000227128A - One-way clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize lock timings of a one way clutch. SOLUTION: In a one-way clutch 5 to switch a drive member 1 and a driven member 2 concentrically arranged inside and outside in a radial direction in a lock condition of synchronous rotation and in a free condition of relative rotation, feed screw mechanisms 10, 11 are applied instead of conventional wedge members. Lock and free actions are implemented by increasing or decreasing a feed amount of a movable thread member 11 and a fixed thread member 10 of the feed screw mechanism to unite or separate those members 10, 11. Thereby, sliding actions existing in the conventional wedge members are eliminated. That allows to control lock and free action timing always constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a one-way clutch. The one-way clutch is built in a feed mechanism of various functional devices, a pulley mounted on an auxiliary machine driven via a belt from a crankshaft of an engine of an automobile or the like, and the like. Examples of the aforementioned auxiliary equipment include a compressor for an air conditioner of an automobile, a water pump, an alternator, a cooling fan, a crank pulley, and the like.

[0002]

2. Description of the Related Art A one-way clutch switches between a locked state in which a driving member and a driven member disposed concentrically inside and outside in the radial direction are synchronously rotated, and a free state in which the driven member and the driven member are relatively rotated. Types and types using sprags are known.

For example, in a one-way clutch using a roller, a wedge-shaped space is provided at several places around a radially opposed space between both members, and a roller serving as a wedge member is disposed in the wedge-shaped space. The wedge-shaped space is provided, for example, on a cam surface formed of a concave curved surface that is concave outward in the radial direction provided at several places on the inner peripheral surface of the annular member disposed radially outward, and on the radially inner side. It is formed by the circular outer peripheral surface of the shaft member.

On the other hand, in a one-way clutch of the type using sprags, sprags as wedge members are arranged at several locations on the circumference of a radially opposed space between the two members, and the rotational speed of the driving member is higher than that of the driven member. The sprags are locked when the rotation speed of the driving member becomes slower than that of the driven member.

[0005]

In a one-way clutch of the type using rollers and sprags as described above, in a locked state, the two members are integrated by the frictional force of a wedge member. In situations where the angular velocity increases, such as in the high-speed rotation range where the centrifugal force increases or in the low-speed range where the rotation fluctuation is large, or in situations where the kinematic viscosity of the internal lubricant increases, such as at low temperatures, the wedge member slips and the engagement becomes weak It is pointed out that there is a tendency. When such a phenomenon occurs, it can be said that the lock timing becomes unstable.

In view of such circumstances, an object of the present invention is to stabilize lock timing in a one-way clutch.

[0007]

A one-way clutch according to the first aspect of the present invention has a locked state in which a driving member and a driven member disposed concentrically inside and outside in the radial direction are synchronously rotated and a free state in which the driven member and the driven member are relatively rotated. The driving member is provided in a fixed state with respect to the peripheral surface facing the driven member in the driving member, and the peripheral surface facing the driven member is formed in a tapered shape, and the tapered peripheral surface is A fixed screw member having a spiral groove, and a driven member which is fitted in a state in which the driven member is slidably displaceable only in the axial direction with respect to a peripheral surface facing the fixed screw member and faces a tapered peripheral surface of the fixed screw member. A movable screw member having a peripheral surface formed in a taper shape parallel to the tapered peripheral surface and having a spiral groove on the tapered peripheral surface to be screwed with a spiral groove of the fixed screw member. A state in which the movable screw member is slid in the axial direction with respect to the fixed screw member in accordance with a relative rotational speed difference between the driving member and the driven member, thereby deepening the screwing and integrating with the fixed screw member. Is removed and the state is switched to the state of separation.

According to a second aspect of the present invention, there is provided the one-way clutch according to the first aspect, wherein the movable screw member is resiliently biased toward a side where screwing of the movable screw member into the fixed screw member is deepened. It has a member.

In short, the present invention is a one-way clutch utilizing a feed screw mechanism, and does not use a plurality of wedge members as in the conventional example. Disappears.

The operation of the one-way clutch of the present invention is as follows.
When the rotation speed of the driving member becomes faster than that of the driven member, the movable screw member slides along the axial direction in a direction to deepen the screwing into the fixed screw member, and the movable screw member and the fixed screw member are integrated. Since the driving member and the driven member are in a locked state in which they can rotate synchronously, rotational power is transmitted from the driving member to the driven member.

On the other hand, when the rotation speed of the driven member is higher than that of the driving member, the movable screw member slides in the axial direction in a direction to make the screwing of the fixed screw member shallower, so that the spiral groove of the movable screw member is formed. Is disengaged from the spiral groove of the fixed screw member, and the driving member is in a free state in which the driving member relatively rotates with respect to the driven member, so that rotational power is not transmitted from the driving member to the driven member.

As described above, the sliding amount of the movable screw member from the locked state to the free state is physically regulated by the inclination angle of the tapered peripheral surface between the movable screw member and the fixed screw member. , The free operation timing is always constant.

According to the second aspect of the present invention, if the resilient urging member is provided, the play of the threaded portion between the movable screw member and the fixed screw member can be eliminated, and the sliding operation of the movable screw member can be performed. Becomes smoother.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on embodiments shown in the drawings.

The one-way clutch of the present invention can be built in pulleys of various auxiliary machines mounted on engines such as automobiles. Therefore, in this embodiment, an example in which a one-way clutch is incorporated in a pulley of an alternator as an auxiliary machine will be described.

1 to 3 show an embodiment of the present invention. 1 is a sectional view showing a free state of a pulley unit having a built-in one-way clutch, FIG. 2 is a sectional view showing a locked state of the pulley unit of FIG. 1, and FIG. 3 is (3)-of FIG. (3) It is an arrow view of a line section.

In the figure, A indicates the entire pulley unit. The pulley unit A includes a pulley 1 as a driving member, a rotating shaft 2 as a driven member, two rolling bearings 3 and 4, and a one-way clutch 5.

The pulley 1 is formed in an annular shape, and has a belt groove 1a around which a drive belt 6 is wound.
Is provided.

The rotating shaft 2 serves as an input shaft of the alternator, and is arranged concentrically on the inner periphery of the pulley 1.

The rolling bearings 3 and 4 are composed of a pulley 1 and a rotating shaft 2.
The bearings are arranged on both axial sides of the opposed space and mainly bear the radial load, and are, for example, deep groove ball bearings.

The one-way clutch 5 includes a pulley 1 and a rotating shaft 2.
Is disposed between the two rolling bearings 3 and 4 in a space opposed to the above, and is appropriately switched between a locked state in which the rotational power is transmitted from the pulley 1 to the rotary shaft 2 and a free state in which the rotational power is not transmitted. is there.

The structure of the one-way clutch 5 will be described in detail. The one-way clutch 5 includes a fixed screw member 10 formed of an annular body having an inner peripheral surface formed into a tapered shape, a movable screw member 11 formed of an annular body having an outer peripheral surface formed into a tapered shape,
A guide ring 12 for guiding an axial sliding operation of a movable screw member 11 and a coil spring 13 as a resilient urging member
And

The fixed screw member 10 is fixedly fitted to the inner peripheral surface of the pulley 1 as a driving member by press-fitting, and guides the sliding operation of the movable screw member 11.
The inner peripheral surface of the fixing screw member 10 is formed in a tapered shape, and a spiral groove 10a is provided in the tapered inner peripheral surface.

The movable screw member 11 is fitted slidably only in the axial direction on the outer peripheral surface of the rotating shaft 2 as a driven member. The outer peripheral surface of the movable screw member 11 is formed in a tapered shape, and the spiral groove 1 formed on the tapered inner peripheral surface of the fixed screw member 10 is formed on the tapered outer peripheral surface.
A spiral groove 11a screwed to 0a is formed. Also,
A spline 11b is formed on the inner peripheral surface of the movable screw member 11.

The inclination angle of the tapered inner peripheral surface of the fixed screw member 10 and the inclination angle of the tapered outer peripheral surface of the movable screw member 11 are set to be substantially the same. The sliding range of the movable screw member 11 in both axial directions is regulated by the screwing depth of the screw member 11. Further, each peak (tooth tip) of the spiral groove 10a of the fixed screw member 10 and the spiral groove 11a of the movable screw member 11 has a rounded R shape so as not to be easily worn.

The guide ring 12 is externally fitted to the area of the two rolling bearings 3 and 4 on the outer peripheral surface of the rotating shaft 2 so as to be immovable in the circumferential and axial directions. On the surface, the spline 1 of the movable screw member 11
A spline 12a that fits spline with 1b is formed. It should be noted that not only spline fitting but also keys and serrations can be used.

The coil spring 13 is disposed in a compressed state between the movable screw member 11 and the inner ring of the rolling bearing 4 on the left side in the figure on the outer periphery of the rotating shaft 2 and fixes the movable screw member 11 by the extension restoring force. This is to resiliently bias the screw member 10 in a direction to deepen the screwing.

Next, the operation of the pulley unit A will be described.

First, when the pulley 1 is rotated clockwise by the belt 6 when viewed from the right side in the figure, the fixing screw member 10 of the one-way clutch 5 fixed to the pulley 1 rotates synchronously with the pulley 1. become. As a result, the movable screw member 11 of the one-way clutch 5 slides in the axial direction to the right in the drawing, that is, to the side where screwing into the fixed screw member 10 is deepened. Thus, the movable screw member 11
When the fixed screw member 10 is screwed to the maximum, the sliding operation of the movable screw member 11 is stopped, and the movable screw member 11 and the fixed screw member 10 are integrated. Thus, the pulley 1 is integrated with the rotating shaft 2. This state is the locked state of the one-way clutch 5. As a result, the rotational power is transmitted from the pulley 1 to the rotary shaft 2 at a ratio of approximately 1: 1.

On the other hand, when the pulley 1 is rotated counterclockwise as viewed from the right side in the drawing, the fixing screw member 10 of the one-way clutch 5 fixed to the pulley 1 rotates synchronously with the pulley 1. . As a result, the movable screw member 11 of the one-way clutch 5 moves in the left direction in the drawing, that is, the fixed screw member 1
The shaft slides in the axial direction against the elastic biasing force of the coil spring 13 to the side where the screwing with respect to 0 is made shallower. In this way, when the screwed state between the movable screw member 11 and the fixed screw member 10 is completely released, the sliding operation of the movable screw member 11 is stopped, and the movable screw member 1 is stopped.
1 and the fixing screw member 10 become relatively rotatable. This state is the free state of the one-way clutch 5. as a result,
The transmission of rotational power from the pulley 1 to the rotary shaft 2 is cut off.

In the case where the pulley 1 is used to rotate only in the clockwise direction, if the rotation speed of the pulley 1 temporarily decreases during the rotation of the pulley 1, the rotation shaft 2 Since the rotational speed is momentarily higher than the rotational speed of the pulley 1 due to the rotational inertia force, the movable screw member 11 of the one-way clutch 5 rotates clockwise together with the rotating shaft 2 while moving in the left direction in the figure, that is, with the fixed screw member 10. Since it slides in the axial direction against the elastic urging force of the coil spring 13 in the direction of releasing the screwed state, as described above, the pulley 1 and the rotary shaft 2 are in a free state in which the rotary shaft 2 is relatively rotated. The transmission of rotational power from the pulley 1 to the rotary shaft 2 is cut off.

Thereafter, when the rotation speed of the pulley 1 becomes higher than that of the rotation shaft 2, as described above, the movable screw member 11 of the one-way clutch 5 moves to the right side in the drawing, that is, the side on which the screwing into the fixed screw member 10 is deepened. As the one-way clutch 5 is locked in the axial direction, the rotational power is transmitted from the pulley 1 to the rotary shaft 2.

As described above, even if the rotational speed of the pulley 1 fluctuates in height (pulsation), the one-way clutch 5 is appropriately switched between the locked state and the free state, and the rotational speed of the pulley 1 is pulsated. Is rectified and transmitted to the rotating shaft 2 linearly. Further, even when the rotation speed of the pulley 1 is reduced from high speed to low speed, the one-way clutch 5 is in a free state and the rotating shaft 2 can be rotated at high speed by its own rotational inertia. Efficiency can be increased.

As described above, the one-way clutch 5 employs a feed screw mechanism without using a wedge-shaped member as in the conventional example. Sliding of the wedge-shaped member, which may occur, can be eliminated. In the one-way clutch 5 of the present invention, the movement of the movable screw member 11 corresponding to the conventional wedge-shaped member is guided by the tapered spiral grooves 10a, 11a to regulate the movement range. The lock and free operation timings of the clutch 5 can always be kept constant, and the operation responsiveness can be stabilized.

It should be noted that the present invention is not limited to only the above embodiment, and various applications and modifications are conceivable.

(1) In the above embodiment, the pulley 1 is used as a driving member and the rotary shaft 2 is used as a driven member. In this case, it is necessary to attach the fixed screw member 10 to the rotating shaft 2 and the movable screw member 11 to the pulley 1 respectively.

(2) In the above embodiment, the guide ring 12 having the spline 12a is attached to the outer periphery of the rotary shaft 2. However, the guide ring is formed by forming a spline on the outer peripheral surface of the rotary shaft 2. 12 may not be used.

(3) In the above-described embodiment, an example has been described in which the one-way clutch 5 is incorporated in a pulley of an alternator as an auxiliary device of an automobile. However, the one-way clutch 5 can be incorporated in a pulley of another auxiliary device. In any case, one-way clutch 5
The movable screw member 11 of the one-way clutch 5 is attached to the driven member side so as to be slidable only in the axial direction.
0 may be fixedly attached to the drive member side.

[0039]

In the one-way clutch according to the first and second aspects of the present invention, the amount of screwing of the movable screw member and the fixed screw member of the feed screw mechanism is increased / decreased, and the two are unified and disengaged. Since the locking and free operation are performed by switching to the above, the sliding element such as the wedge-shaped member of the conventional example can be eliminated, and the locking and free operation timing can be constantly controlled, The operation responsiveness can be stabilized.

In particular, if the movable screw member is elastically urged in one of the axial directions by the elastic urging member as in claim 2, the play of the threaded portion between the movable screw member and the fixed screw member is provided. Can be eliminated, and the sliding operation of the movable screw member can be made smooth.

As described above, according to the present invention, a one-way clutch exhibiting a stable and highly reliable clutch function can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of an upper half showing a free state in a pulley unit including a one-way clutch according to an embodiment of the present invention.

FIG. 2 is a sectional view of the upper half of the pulley unit of FIG. 1 showing a locked state.

3 is a sectional view taken along line (3)-(3) of FIG.

[Explanation of symbols]

 Reference Signs List A pulley unit 1 pulley 2 rotating shaft 5 one-way clutch 10 one-way clutch fixed screw member 10a helical groove of fixed screw member 11 one-way clutch movable screw member 11a helical groove of movable screw member 12 guide ring 13 coil spring

Claims (2)

[Claims] 1. A one-way clutch for switching between a locked state in which a driving member and a driven member disposed concentrically inside and outside in a radial direction and a free state in which the driven member and the driven member are relatively rotated, wherein the driven member is driven by the driven member. A fixed screw member provided in a fixed state with respect to a peripheral surface facing the member and having a tapered peripheral surface facing the driven member and having a spiral groove in the tapered peripheral surface; In the above, the peripheral surface facing the fixed screw member is slidably fitted only in the axial direction so as to be slidable only in the axial direction, and the peripheral surface facing the tapered peripheral surface of the fixed screw member is parallel to the tapered peripheral surface. A movable screw member having a tapered peripheral surface and having a spiral groove screwed into the spiral groove of the fixed screw member on the tapered peripheral surface; Depending on the rotational speed difference,
When the movable screw member is slid in the axial direction with respect to the fixed screw member, the movable screw member is switched between a state in which the movable screw member is deepened and integrated and a state in which the screw is removed and separated. One-way clutch. 2. The one-way clutch according to claim 1, further comprising a resilient biasing member for resiliently biasing the movable screw member toward a side where screwing of the movable screw member into the fixed screw member is deepened. A one-way clutch.