JPH0754874A - One-way clutch - Google Patents

Abstract

PURPOSE:To provide an inexpensive one-way clutch which has high meshing force, and relatively low slipping torque. CONSTITUTION:An inner ring 15 is inserted into a hollow cylindrical outer ring 11 movablly in a circumferential direction, which outer ring 11 is formed with a tapered portion 12 having a gradually decreasing inner diameter, and a comparatively steep stepped portion 13 on the end of the tapered portion 12 continued to the above inner diameter. The inner ring 15 is a hollow cylindrical body having ends opposed to each other through a slit 17. A holding window 18 which holds a needle roller 19 is formed on one circumferential end 15a opposing to the other end across the slit 17. The roller 19 is projected in both inward and outward directions from the holding window 18. The circumferential end 15a to which the roller 19 is installed is displaceably formed in a diameter direction. A rotary shaft fitted into the hollow space in the inner ring 15 is locked in rotation in one direction, and slipped in rotation in the other direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-way clutch, and more particularly to a one-way clutch attached to a rotary shaft of an office automation equipment or the like.

[0002]

2. Description of the Related Art Conventionally, one-way clutches having several structures have been used as a transmission mechanism for rotary motion. Among them, small-diameter one-way clutches used in OA equipment and the like are classified into the following two types according to their basic functions and structures.

As shown in FIG. 5, a large number of needle rollers 1 are arranged in each wedge-shaped space formed on the inner peripheral surface of an inner ring (outer race) 2, and each needle roller 1 is spring 3. Is pressed in the circumferential direction by a roller, and a roller is engaged between each wedge-shaped space portion of the inner ring 2 and the rotating shaft S when the rotating shaft S is rotated in one direction, and the frictional force connects the rotating shaft S and the inner ring 2 to each other. It has a structure that locks. The one-way clutch having such a structure is used in a relatively high-grade model.

The other one has a structure in which the coil spring 4 is contacted in a form wound around a rotary shaft S as shown in FIG. 6, and one end thereof is fixed to an inner ring (not shown). In the case of the one-way clutch having this structure, when the rotating shaft S is to be rotated in the locking direction, the coil spring 4 is twisted in the tightening direction due to the friction between the rotating shaft S and the contact surface of the coil spring 4. The inner diameter of the coil spring 4 is reduced.

As a result, the frictional force with the rotating shaft S is increased and fixed. When the coil spring 4 is rotated in the idling direction, the coil spring 4 is twisted in the direction in which the inner diameter of the coil spring 4 increases, so that the frictional force decreases and the coil spring 4 idles with a slight torque.

[0006]

Although the two typical one-way clutches of the prior art as described above have been widely put into practical use, there have been various problems in their intended use. For example, the former model is the best in terms of performance because the meshing force (lock torque) is high and the idling torque is small. However, this clutch has many drawbacks such as a large number of parts, a complicated structure, and a high price.

On the other hand, the latter model is considerably lower in price than the former, but the inner surface of the coil spring 4 and the surface of the rotating shaft are in close contact with each other due to the elasticity of the spring 4 to some extent. Therefore, there is a drawback that frictional force acts on this surface even during idling, the idling torque is several times larger than that of the former one-way clutch, and it cannot be used in a field where the idling torque is limited.

Generally, in the field of using a small one-way clutch, a clutch having an intermediate function and price between the former model and the latter model is desired, and development of such a small one-way clutch is desired. It was rare.

SUMMARY OF THE INVENTION An object of the present invention is to provide a low-priced one-way clutch having a high meshing force and a relatively low idling torque.

[0010]

SUMMARY OF THE INVENTION The present invention is a one-way clutch, for example, a small one-way clutch that can be used for a paper feeding mechanism in a so-called OA device such as a fax machine. Is configured.

That is, in the one-way clutch of the present invention, a taper portion whose inner diameter is gradually reduced and a relatively steep step portion which is formed at the end portion of the taper portion on the inner diameter gradually decreasing side and is relatively steep is formed on the inner peripheral surface. A hollow cylindrical outer ring formed,
An inner ring that is rotatably inserted into the outer ring and has a hollow cylindrical body with both ends in close proximity to each other in the circumferential direction with a gap therebetween, and a holding window formed in one end that faces in close proximity with the gap in between. , A roller disposed in the holding window and protruding inward and outward in the radial direction from the holding window, and means for supporting the one end in the circumferential direction to which the roller is attached so as to be displaceable in the radial direction. The rotary shaft is inserted into the hollow portion of the inner ring to lock one rotation of the rotation shaft and idle the other rotation.

Further, in the one-way clutch of the present invention, in addition to the above-mentioned characteristics, the means for supporting the one end in the circumferential direction so as to be displaceable in the radial direction is different from the edge of the one end in the circumferential direction with the holding window as a boundary. At least one axially provided on the opposite side
It is characterized in that it consists of a notch in a book.

[0013]

According to the one-way clutch of the present invention, it is assumed that the rotary shaft relatively inserted into the inner ring of the clutch rotates in one direction. The rotation direction of the rotating shaft is such that the inner ring contacting the shaft is moved by the frictional force of the roller held at one end portion in the circumferential direction toward the tapered portion of the outer ring.

When the roller moves to the taper portion that gradually reduces the inner diameter of the outer ring due to the movement of the inner ring due to the rotation of the rotary shaft, the roller is pushed inward in the radial direction by the taper portion. One end in the circumferential direction of the inner ring holding this roller by the holding window is supported so that it can be displaced in the radial direction, so the roller is displaced inward in the radial direction, and as a result, there is a constriction between the outer ring and the shaft. It This causes strong frictional contact between the rotary shaft and the inner peripheral surface of the inner ring, and as a result, the rotary shaft is connected to the outer ring via the inner ring and is in a locked state.

Further, when the rotating shaft rotates in the opposite direction to the above, the inner ring moves in the opposite direction to the above, the roller separates from the taper portion of the outer ring, and the outer peripheral surface of the rotating shaft radially outwards. In response to a pushing-back force to the outer circumferential end, the one end in the circumferential direction is displaced radially outward and released from the confining pressure between the outer ring and the rotary shaft. However, at the same time, the other end of the inner ring engages with a relatively steep step at the inner diameter gradually decreasing end of the tapered portion, and the inner ring is prevented from moving. At this time, since the forced meshing force between the rotating shaft and the outer ring via the roller is released as described above, there is almost no contact pressure between the rotating shaft and the inner ring, and thus the rotating shaft idles.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The one-way clutch of the present invention will now be described in more detail with reference to the embodiments shown in the drawings. FIG. 1 shows a one-way clutch 10 according to an embodiment of the present invention. The one-way clutch 10 of this embodiment includes a hollow cylindrical outer casing or outer ring 11 made of steel. On the inner peripheral surface of the outer ring 11, there are formed a tapered portion 12 having a gradually decreasing inner diameter, and a relatively steep step portion 13 so as to return to the inner diameter of the outer ring 11 at an end portion on the gradually decreasing inner diameter of the tapered portion 12. ing.

The stepped portion 13 functions as a stopper when the inner ring is moved in one direction in the circumferential direction, which will be described later. As shown in FIG. 4, the tapered portion 12 and the stepped portion 13 form a concave portion 14 so as to be partially crushed from the outer peripheral surface of the outer ring 11 by a machine or tool such as a press. It can be easily formed by bulging that portion toward the inner peripheral surface. Inside the outer ring 11, a hollow cylindrical inner ring 15 made of synthetic resin is inserted so as to be movable in the circumferential direction.

As shown in FIG. 2, the inner ring 15 is prevented from slipping off in the axial direction by flange portions 16 formed by bending both axial ends of the outer ring 11 inward in the radial direction. At this time, the portion where the flange portion 16 is formed is as shown in FIG.
As shown in FIG.
It is a portion extending from 0 degree to 270 degrees.

Since the inner ring 15 is made of synthetic resin as described above, the inner ring 15 can be integrally molded. However, structurally explaining it, a shaft to be used inserted into the hollow portion of the inner ring 15 as shown in FIG. That is, one slit 17 in the axial direction is formed in one location on the peripheral surface of a completely hollow cylindrical body having a basic inner diameter slightly larger than the outer diameter of the rotating shaft S (about 0.01 to 0.05 mm in diameter) to form a gap. It is opened.

Due to this slit 17, the inner ring 15 is formed as shown in FIG.
As shown in FIG.
It has a hollow cylindrical shape with a and 15b as a whole. A rectangular window 18 that is long in the axial direction is formed at one end portion 15a in the circumferential direction of the inner ring 15.
A needle roller 19 extending in the axial direction of the inner ring 15 and having a diameter substantially equal to the thickness of the inner ring 15 is rotatably held at 8.

At that time, the holding window 18 is formed by the needle roller 1.
On the inner peripheral surface side, the width dimension is shorter than the diameter of the needle roller 19 so that 9 does not fall inside. Two notches 2 extending in the axial direction are formed on the inner ring 15 on the side opposite to the edge of the one end 15a in the circumferential direction with the window 18 as a boundary.
0 and 21 are provided in a zigzag pattern. That is, one notch 20 is made from one side in the axial direction of the inner ring 15 to the vicinity of the other side, and the other notch 21 is adjacent to the one notch 20 and parallel to the other side. It is put up to the vicinity.

As a result, the one end portion 15a in the circumferential direction holding the needle roller 19 can be partially displaced in the radial direction. That is, when the needle roller 19 is attached to the outer ring 11 while being held, the needle roller 19 is attached in a state in which the gap between the notches 20 and 21 is compressed, so that the needle roller 19 is fixed between the inner surface of the tapered portion and the outer circumference of the shaft. It will create a state that can be pressed by force. Further, as is apparent from FIG. 1, the circumferential one end 15a is evenly ground on the inner circumferential surface side and the outer circumferential surface side from the vicinity where the cut portion 20 is formed to the edge of the circumferential one end 15a. And its thickness has been reduced.

Therefore, when the rotary shaft S, which will be described later, is fitted into the hollow portion of the inner ring 15, the inner peripheral surface at the one end portion 15a in the circumferential direction opens a space 22 with respect to the rotary shaft S, and the outer peripheral surface is A space 23 is also formed on the inner peripheral surface of the outer ring 11. The spaces 22 and 23 are about 0.3 mm. Needle roller 19 arranged in holding window 18
Has a diameter substantially equal to the thickness of the portion other than the one end portion 15a of the inner ring 15 as described above, and thus the rotary shaft protruding from the inner peripheral surface and the outer peripheral surface of the holding window 18 and inserted into the hollow portion of the inner ring 15. It is in a state of lightly contacting S and the outer ring 11.

The one-way clutch 10 thus constructed is used such that the rotary shaft S is relatively fitted into the hollow portion of the inner ring 15 as shown in FIG. At that time, the rotating shaft S is in contact with the needle roller 19.
Therefore, when the rotating shaft S rotates to the left in FIG. 1, contact friction of the inner ring 15 contacting the rotating shaft S or rotation of the needle roller 19 by the rotating shaft S causes
The inner ring 15 moves in the same direction along with the rotation axis S.

As a result, one end portion 15 of the inner ring 15 in the circumferential direction is formed.
When the needle roller 19 held by a comes to the taper portion 12 of the outer ring 11, the circumferential one end portion 15a supported so as to be displaceable in the radial direction is radially inward of the needle roller 19 due to the gradually decreasing inclined surface of the inner diameter. Is allowed, and as a result, the needle roller 19 is pinched between the rotating shaft S and the tapered portion 12 of the outer ring 11. Therefore, the contact friction between the rotating shaft S and the inner peripheral surface of the inner ring 15 increases, and the two are connected. Therefore, the rotary shaft S is locked.

On the contrary, when the rotary shaft S rotates to the right as viewed in FIG. 1, as described above, the rotary shaft S and the inner ring 15 are rotated.
The inner ring 15 also moves to the right by a light contact with. As a result, the needle roller 19 has the tapered portion 12
And is released from the clamping pressure between the rotation shaft S and the outer ring 11. At the same time, the other end 15b in the circumferential direction of the inner ring 15 comes into contact with the step portion 13 at the end portion on the inner diameter gradually decreasing side of the taper portion 12 to prevent relative movement with respect to the outer ring 11. As a result, the contact frictional force between the inner peripheral surface of the inner ring 15 and the rotating shaft S returns to a normal extremely small state, so that the rotating shaft S idles with respect to the inner ring 15.

In this way, when the rotating shaft S rotates in one direction, it engages with the outer ring 11 via the inner ring 15 and becomes in a locked state, while when the rotating shaft S rotates in the other direction, the rotating shaft S and the outer ring 11 are separated from each other. The connection is released by the movement of the inner ring 15, and the rotation shaft S runs idle with respect to the inner ring 15.
However, when assembling the inner ring 15 into the outer ring 11,
As shown in FIG. 1, the taper portion 12 formed on the outer race 11 must be fitted so that the maximum inner diameter decreasing portion is located in the slit 17 of the inner race 15.

In the one-way clutch 10 of the above-described embodiment, when it is necessary to increase the lock torque between the rotary shaft S and the inner ring 15, the inner peripheral surface of the inner ring 15 (the contact surface with the rotary shaft S) is changed. It is preferable to perform serration processing. In this case, it goes without saying that the idling torque has no adverse effect.

Further, in the above-mentioned embodiment, if the needle roller 19 is made of stainless steel such as SUS, that is, stainless steel, there is no fear of rusting at the contact portion of the rotating shaft, and the durability can be improved. Needle roller 1
If 9 is made of stainless steel, it is natural that there is no need for rust preventive coating oil.

As described above, according to the present invention,
A needle roller was held at one end in the circumferential direction of a hollow cylindrical inner ring provided with a slit in the axial direction, and this one end was formed so as to be displaceable in the radial direction, and a taper portion with a gradually decreasing inner diameter was formed on the inner circumferential surface. With a very simple structure in which the inner ring is rotatably inserted into the outer ring, it is possible to provide a low-priced one-way clutch having a high meshing force and a relatively low idling torque.

Further, according to the one-way clutch of the present invention, the eccentricity of the inner ring by one roller increases the frictional force with the rotating shaft to perform the locking, so that it is not necessary to strictly regulate the shape accuracy of the roller contact portion. It also has effects such as.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a one-way clutch according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the one-way clutch of the embodiment shown in FIG. 1 along the line AA.

FIG. 3 is a perspective view showing an inner ring that constitutes the one-way clutch of the embodiment shown in FIG.

FIG. 4 is a perspective view showing a one-way clutch of the embodiment shown in FIG.

FIG. 5 is a sectional view schematically showing a conventional small one-way clutch.

FIG. 6 is a perspective view schematically showing another conventional small one-way clutch.

[Explanation of symbols]

 10 One-Way Clutch 11 Outer Ring 12 Inner Diameter Reduced Tapered Section 13 Stepped Section 14 Recess 15 Inner Ring 15a Circumferential One End 15b Circumferential Other End 16 Flange 17 Slit 18 Holding Window 19 Needle Roller 20 Notch 21 Notch 22 Space 23 Space S Axis of rotation

Claims (2)

[Claims] 1. A hollow cylindrical shape having an inner peripheral surface formed with a taper portion whose inner diameter is gradually reduced and a relatively steep step portion which is formed at an end portion on the inner diameter gradually decreasing side of the taper portion so as to return to the inner diameter. Outer ring, an inner ring rotatably inserted in the outer ring, and both ends thereof circumferentially facing each other through a gap to form a hollow cylindrical body, and one end portion facing each other across the gap. Holding window, a roller arranged in the holding window and protruding inward and outward in the radial direction from the holding window, and means for supporting the circumferential one end portion to which the roller is attached so as to be displaceable in the radial direction. A one-way clutch comprising a rotating shaft inserted into a hollow portion of the inner ring to lock one rotation of the rotating shaft and idle rotation of the other direction. 2. A means for supporting the one end in the circumferential direction so as to be displaceable in the radial direction is at least one axially provided on the opposite side of the edge of the one end in the circumferential direction with the holding window as a boundary. The one-way clutch according to claim 1, wherein the one-way clutch comprises a notch.