JPH09292006A - Pulley unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulley unit provided with an one way clutch functioned stablly in a condition in which large rotary centrifugal force is applied. SOLUTION: This pulley unit is provided with a rolling bearing 4 interposed between a rotor 2 and a pulley 3 arranged concentrically on the outer peripheral side of the rotor 2, and a engaging type sprag one way clutch for switching a lock condition for transmitting rotary power between the rotor 2 and the pulley 3 and a free condition for not transmitting rotary power. In the engaging type sprag one way clutch 5, a lock condition is strengthened when rotational centrifugal force is applied on a sprag 51, release of the lock condition is prevented. Since the sprag 51 is pushed on an inner wheel and an outer wheel at all times by rotary centrifugal force in the free condition, all the sprags 51 are locked instantly when the condition is converted from the free condition to the lock condition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pulley unit. The pulley unit of the present invention is, for example, an auxiliary machine of an automobile engine (cooler compressor, alternator,
Used for cooling water pumps, superchargers, hydraulic pumps for steering, etc.).

[0002]

2. Description of the Related Art An alternator such as an alternator of an automobile is driven by the rotational power of a crankshaft of an automobile engine.

That is, a belt is wound around a pulley which is externally fitted and attached to the rotating shaft of the alternator and a pulley which is externally fitted and attached to a crankshaft of an automobile engine. In this case, the alternator is directly driven by the rotational power of the crankshaft.

[0004]

By the way, the above-mentioned conventional example has the following problems.

That is, although the alternator is directly driven by the rotational power of the crankshaft, when the crankshaft is rapidly decelerated from the state where it is rotating at high speed, the alternator cannot rapidly decelerate due to its moment of inertia. And a difference in rotation speed between the alternator occurs. As a result, the belt slides on the alternator pulley, which causes vibration and noise, and damages the belt, which shortens the life of the belt.

Further, it can be said that abrupt deceleration of the pulley of the alternator rotating at a high speed is wasteful because it reduces the power generation action of the alternator.

Therefore, the applicant of the present application installs a one-way clutch between the rotary shaft and the pulley so that when the crankshaft pulley is suddenly decelerated, the crankshaft pulley rotates relative to the alternator pulley. I thought it would be better to cut off the transmission of power. However, in general, a roller type is mainly used as the one-way clutch, but in this type of one-way clutch, the permissible rotational speed is about 6,000 to 8,000 rpm, and the one-way clutch is Because the crankshaft pulley rotates at a higher speed than that, it cannot be used.

Particularly, in the prior art, since the concave cam surface for forming the wedge-shaped space is formed on the inner peripheral surface of the member which becomes the outer ring of the one-way clutch, the roller of the one-way clutch is rotated by the centrifugal force at the time of high speed rotation. Is likely to move to the free side, so that one of the rollers may not be able to maintain the locked state. If this happens, the rollers that are still in the locked state will slip over the rotating shaft and cause abnormal heat generation as the overall balance is lost, causing seizure in a short time or clogging due to solidification of the lubricant. There is.

Therefore, an object of the present invention is to provide a pulley unit provided with a one-way clutch that functions stably even in a situation where a large rotational centrifugal force is exerted.

[0010]

A first pulley unit of the present invention comprises a rolling bearing interposed between a rotating body and a pulley arranged concentrically on the outer periphery of the rotating body, and the rotating body and the pulley. An engagement-type sprag-type one-way clutch that switches between a locked state in which rotational power is transmitted and a free state in which rotational power is not transmitted is provided.

A second pulley unit of the present invention transmits rolling power between a rolling bearing and a rolling bearing interposed between a rotating body and a pulley arranged concentrically on the outer periphery of the rotating body. An engagement type sprag type one-way clutch that switches between a locked state and a non-transmitted free state, wherein the rolling bearing has at least an inner / outer ring and a rolling element, and the one-way clutch is an inner rolling bearing.・ Built-in between outer rings on the side of the raceway.

The engagement-type sprag-type one-way clutch strengthens the locked state when the rotating centrifugal force acts on the sprag, and the locked state is not released. Further, even in the free state, since the sprags are constantly pressed against the inner ring and the outer ring by the centrifugal force of rotation, all the sprags are instantly locked when the free state is shifted to the locked state. In this way, the operation is stable regardless of the use situation, and the reliability is increased.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the embodiments shown in FIGS.

1 to 5 relate to an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a pulley unit, FIG. 2 is a partially enlarged view of the pulley unit, and FIG. 3 is (3) of FIG. −
(3) Line sectional view, FIG. 4 is a perspective view showing the cage, FIG.
[Fig. 5] is a perspective view of the cage viewed from the opposite side of Fig. 4.

The pulley unit 1 shown in the figure comprises a cylindrical rotating body 2 and a pulley 3 made of sheet metal such as JIS standard SPCC material.
And a rolling bearing 4 such as a deep groove type ball bearing, and an engagement type sprag one-way clutch 5.

The rotating body 2 is integrally fitted on a rotating shaft or the like, and the pulley 3 is concentrically arranged on the outer periphery of the rotating body 2 via a rolling bearing 4 having a one-way clutch 5 built therein. Has been done.

The rolling bearing 4 comprises inner and outer rings 41, 42, a rolling element 43 composed of a plurality of balls, and a corrugated cage 44, and has a sealed structure with a seal (reference numeral omitted) in the illustrated example. The inner and outer rings 41, 42 are set to be longer on one side in the axial direction than those of general bearings, and are made of bearing steel or the like. The raceways of the rolling elements 43 are provided in the axial half regions of the inner and outer rings 41, 42, and the one-way clutch 5 described below is provided in the remaining axial half regions.

The one-way clutch 5 includes a plurality of sprags 51.
, A cylindrical retainer 52, and a plurality of springs 53, and the sprag 51 and the spring 53 with respect to the retainer 52.
Is held.

The sprag 51 has a rectangular parallelepiped upper and lower surfaces which are curved cam surfaces, and a front surface is provided with a partially arcuate convex cam portion. The sprag 51 is formed of a metal such as JIS standard SUJ2.

The cage 52 is provided at several circumferential positions so as to penetrate radially inward and outward, and accommodates the sprag 51 in a tiltable manner, and a column portion between the sprag pockets 521 adjacent in the circumferential direction. A spring mounting portion 522 provided in 524 and mounted in a state in which the spring 53 presses the sprag 51 to the upright posture, and an annular portion 525 on one axial side.
On the outer peripheral surface of a, there are provided convex portions 523 which are provided at several circumferential positions so as to project radially outward. The cage 52 is made of synthetic resin such as reinforced polyamide.
The outer diameter of the annular portion 525b on the other side in the axial direction is set to be larger than the outer diameter of the annular portion 525a on the one side in the axial direction, and is formed on the inner peripheral surface shoulder portion of the outer ring 41 of the rolling bearing 4. A non-contact sealing portion having a labyrinth effect is formed between the step portion 412 and the step portion 412.

The spring 53 is composed of a leaf spring curved in a substantially U shape, and has a main body 531 which is positioned and mounted on the spring mounting portion 522 of the retainer 52, and the sprag 51 is elastically urged by a restoring force caused by compression. Urging tongue 532.
The spring 53 is formed of a metal such as JIS standard SUS301. The spring 53 is attached to the retainer 5.
2, the tongue piece 532 has the sprag 5
1 becomes a non-compressed natural state when not incorporated in the retainer 52, but becomes a compressed state when the sprag 51 is incorporated in the retainer 52.
1 is pressed to the upright posture, and the sprag 51, the retainer 52, and the spring 53 are not separated.

Further, the spring mounting portion 522 of the retainer 52.
Consists of a notch which is opened in the outer diameter side so as to be continuous with the sprag pocket 521 and which is substantially inverted L-shaped in side view. Two kinds of protrusions 526, 5 are provided in this notch.
The main body 531 of the spring 53 is positioned in a state where the tongue piece 532 of the spring 53 is projected into the sprag pocket 521 by 26, 527 and 527. Further, in the pillar portion 524 of the retainer 52, the ridges 52 extending in the radial direction are provided at two axial positions on the inner wall surface on the sprag pocket 521 side.
8 is provided in a protruding manner, and the raised portion 528 is provided with a concave guide surface 529 for guiding the tilting movement of the sprag 51. In addition, between the two raised portions 528 and between the two raised portions 528 and the annular portion 525 on both axial sides of the retainer 52.
The space between a and 525b is used to store a lubricant such as grease.

A circumferential groove 411 continuous in the circumferential direction is provided at the axially substantially central position of the inner circumferential surface of the outer ring 41 of the rolling bearing 4 described above, and the one-way clutch 5 of the one-way clutch 5 is provided to the circumferential groove 411. Since the convex portion 523 of the retainer 52 is slidably engaged with the retainer 52 of the one-way clutch 5,
The outer rings 41, 42 are axially positioned so that they can rotate relative to each other.

By the way, the rolling bearing 4 and the one-way clutch 5 described above are assembled separately and then coupled together. Specifically, since the assembly of the rolling bearing 4 is well known, its description is omitted here. The one-way clutch 5 is assembled by the spring mounting portion 522 of the retainer 52.
After attaching the spring 53 to the outer diameter side in a snap fit manner, the sprag pocket 521 of the retainer 52 is attached.
Insert the sprag 51 against. At the time of inserting the sprag 51, the tongue piece 53 of the spring 53 mounted before that is inserted.
2 is elastically deformed in the compression direction, and due to the restoring force of this tongue piece 532, the sprag 51 is held in an upright posture so as not to fall off. Then, in order to install the one-way clutch 5 in the rolling bearing 4, first, the inner and outer rings 41, 42 of the rolling bearing 4 are to be assembled.
The cage 52 is fitted in from one side in the axial direction.
The radial length of the one annular portion 525a is the inner / outer ring 41,
Since it is slightly larger than the spacing between 42, and the sprag 51 is in an upright posture, it cannot be fitted between the inner and outer rings 41, 42 as it is. Therefore, as a first step, one annular portion 52 of the cage 52 is
By forcibly fitting 5a between the inner and outer rings 41, 42, the convex portion 523 of the annular portion 525a is slightly elastically deformed and pushed in. At this time, a tapered chamfer is applied to the end edge of the convex portion 523 in order to facilitate pushing. In the second step, with the side surface of the sprag 51 in contact with the end surfaces of the inner / outer rings 41, 42, one of the inner / outer rings 41, 42 is rotated in the direction of arrow B in FIG. The frictional force of this rotation causes the sprag 51 to tilt to the free state, so that at this time, if the cage 52 is pushed into the inner / outer rings 41, 42, it can be fitted. Moreover, the amount of pushing is the cage 5
It is assumed that the second convex portion 523 engages with the circumferential groove 421 of the outer ring 42. By this engagement, the elastic deformation of the convex portion 523 is released and the natural state is restored. Then, in this state, the outer diameter portion of the one annular portion 525b of the retainer 52 is located at the step portion 422 of the shoulder portion of the inner peripheral surface of the outer ring 42, which forms the non-contact sealing portion.

The pulley unit 1 described above is attached to an auxiliary machine of an automobile engine (for example, a cooler compressor, an alternator, a cooling water pump, a supercharger, a hydraulic pump for steering, etc.) as shown in FIG. 6, for example. FIG.
FIG. 3 is a diagram schematically showing an accessory drive mode of an automobile engine. In the figure, 81 is an automobile engine, 82 is a crank pulley, 83 is an accessory of the automobile engine, 84 is a belt,
Reference numeral 85 is a tension pulley.

The pulley unit 1 in such a usage form
Will be described. First, when the pulley 3 and the outer ring 42 of the rolling bearing 4 rotate in the same direction as the direction of arrow A in FIG. 3, that is, the pressing direction of the tongue piece 532 of the spring 53, as the crank pulley 82 rotates, the sprag 51 is placed in an upright posture. As a result, the pressing force of the tongue piece 532 is added, and the sprag 51 is locked. Therefore, the outer ring 42 of the pulley 3 and the rolling bearing 4 and the inner ring 41 and the rotary shaft 831 of the auxiliary machine 83 are integrated and rotate in synchronization.

From this state, when the pulley 3 and the outer ring 42 of the rolling bearing 4 are rapidly decelerated as the crank pulley 82 decelerates, the inner ring 41 and the rotating shaft 831 of the auxiliary machine 83 are not rapidly decelerated by the moment of inertia. 3 and the outer ring 42 of the rolling bearing 4 rotate relatively slower than the inner ring 41 and the rotation shaft 831 of the auxiliary machine 83.
As a result, the sprag 51 comes to be in a tilted posture against the pressing force of the tongue piece 532, so that the sprag 51 becomes free. Therefore, the pulley 3 and the outer ring 42 and the inner ring 41 and the rotating shaft 831 are separately rotated, so that the belt 84 does not slip on the pulley 3 and damage or abnormal noise is avoided. To be done.

Even if the pulley 3 and the outer ring 42 of the rolling bearing 4 rotate in the opposite direction, that is, in the direction of arrow B in FIG. 3, the one-way clutch 5 is in the free state.

By the way, when the lock-free operation of the sprag 51 as described above is repeated, although the whole one-way clutch 5 is slightly, one-way clutch 5, for example, arrow A in FIG.
However, since the convex portion 523 of the retainer 52 is slidably guided in the circumferential groove 411 of the outer ring 41 to allow the rotation, microvibration does not occur.

A load such as tension of the belt 84 applied to the pulley 3 of the pulley unit 1 is received by the rolling bearing 4 and hardly acts on the one-way clutch 5. The operation of is performed stably.

Moreover, since the one-way clutch 5 is of the engagement type, the pulley 3 and the rotary shaft 83 of the auxiliary machine 83
In the situation where 1 and 1 are rotating at high speed in synchronization with each other, the sprag 51
When the is locked, it will not shift to the free state. Therefore, from the pulley 3 to the rotary shaft 83 of the auxiliary machine 83
It is possible to reliably and efficiently transmit the power to the gear 1 and to prevent the sprag 51 in the locked state from slipping on the inner ring 41 of the rolling bearing 4, thereby preventing abnormal heat generation of the one-way clutch 5.

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

(1) The pulley unit 1 can be configured as shown in FIG. In this example, a rolling bearing 4 having no inner / outer ring is used, and the inner / outer ring is shared by the rotating body 2 and the pulley 3. Further, the pulley 3 is not made of sheet metal, but is formed into a cylindrical shape by a steel material such as JIS standard S45C material or a synthetic resin such as fiber reinforced plastic (FRP). Further, the one-way clutch 5 is prevented from coming off in the axial direction by the cage 44 of the rolling bearing 4 and one seal. The rolling bearing 4, the pulley 3, and the one-way clutch 5 of this example can be applied to the above embodiment.

(2) The engagement type sprag type one-way clutch 5 may be as shown in FIG. In this one-way clutch 5, a sprag 51 having a substantially hourglass shape in a side view is used, and a spring 53 made of a cylindrical thin plate material as shown in FIG. 9 is used. The operation is basically similar to that of the above-described embodiment.

(3) The one-way clutch 5 may be provided with inner and outer rings, which is not shown.

(4) The one-way clutch 5 is connected to the rolling bearing 4
It can be arranged not only on one side of the track surface but also on both sides.

As described above, various application examples and modification examples have been described, but in addition to these, the present invention can be implemented in various forms without departing from the spirit of the present invention.

[0038]

According to the present invention, the locked state of the one-way clutch can be reliably maintained even in the situation where an excessive rotational centrifugal force is exerted, so that the power transmission can be performed stably. The heat generation of the one-way clutch can be suppressed, and the reliability and life can be improved.

Further, when the pulley is suddenly decelerated, the pulley and the rotating body are relatively rotated to prevent the belt wound around the pulley from slipping. It is possible to avoid the occurrence of abnormal noise and to contribute to extending the life of peripheral members.

In particular, in the pulley unit of the second aspect, the rolling bearing has the one-way clutch built-in, so that it can be easily attached to the pulley and the rotating body, which contributes to the improvement of productivity.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a pulley unit according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view of the pulley unit shown in FIG.

FIG. 3 is a sectional view taken along line (3)-(3) of FIG. 2;

FIG. 4 is a perspective view showing a retainer of a one-way clutch.

5 is a perspective view of the retainer of the one-way clutch seen from the opposite side of FIG.

FIG. 6 is an explanatory view schematically showing an example of an accessory drive mode of an automobile engine.

FIG. 7 is a vertical sectional view showing a pulley unit according to another embodiment of the present invention.

FIG. 8 is a vertical sectional view showing another example of the one-way clutch.

9 is a perspective view showing a part of a retainer of the one-way clutch shown in FIG.

[Explanation of symbols]

 1 pulley unit 2 rotating body 3 pulley 4 rolling bearing 41 inner ring of rolling bearing 42 outer ring of rolling bearing 43 rolling element of rolling bearing 5 one-way clutch 51 sprag 52 of one-way clutch 52 retainer of one-way clutch 53 spring of one-way clutch

Claims (2)

[Claims] 1. A rolling bearing interposed between a rotating body and a pulley concentrically arranged on the outer periphery thereof, and a locked state in which rotational power is transmitted between the rotating body and the pulley and a free state in which the rotational power is not transmitted. A pulley unit comprising an engagement type sprag type one-way clutch for switching between and. 2. A rolling bearing interposed between a rotating body and a pulley concentrically arranged on the outer periphery thereof, and a locked state in which rotational power is transmitted between the rotating body and the pulley and a free state in which the rotational power is not transmitted. An engagement type sprag type one-way clutch for switching between the rolling bearing and the rolling bearing having at least an inner / outer ring and a rolling element, wherein the one-way clutch has a raceway surface side between the inner and outer rings of the rolling bearing. The pulley unit is characterized in that