JP2611925B2 - One-way clutch - Google Patents

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 mounted on a rotating shaft of, for example, OA equipment.

[0002]

2. Description of the Related Art Hitherto, as a one-way clutch as a transmission mechanism of rotational motion, several types of structures have already been used. Among them, small-diameter one-way clutches used for 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 respective wedge-shaped spaces formed on the inner peripheral surface of an inner race (outer race) 2 as shown in FIG. To engage the rollers between the wedge-shaped spaces of the inner ring 2 and the rotating shaft S during one-way rotation of the rotating shaft S, and connect the rotating shaft S and the inner ring 2 by this frictional force. It is of a structure that locks. One-way clutches having such a structure are used for relatively high-end models.

[0004] The other one has a structure in which a coil spring 4 is brought into contact with a rotating shaft S in such a manner as to be wound thereon 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 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.

[0005] Thereby, the frictional force with the rotating shaft S is increased and fixed. When the coil spring 4 rotates in the idling direction, the coil spring 4 is twisted in a direction in which the inner diameter increases, so that the frictional force is reduced and the coil spring 4 idles with a slight torque.

[0006]

Although the above-mentioned two typical one-way clutches of the prior art have been widely used in practice, there have been various problems with respect to the purpose of use. For example, the former model has the best performance in terms of high engagement force (lock torque) and low idling torque. However, this clutch has many drawbacks, such as a large number of parts and a complicated structure, which results in a high price.

[0007] On the other hand, the latter model is considerably cheaper than the former, but the inner surface of the coil spring 4 and the surface of the rotating shaft are closely contacted by a certain pressure due to the elasticity of the spring 4. Therefore, the 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 there is a drawback that it cannot be used in the field where the idling torque is limited.

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

SUMMARY OF THE INVENTION An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a low-cost one-way clutch having a high engaging force and a relatively small idling torque.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a one-way clutch, for example, a small one-way clutch which can be used for a paper feed mechanism in a so-called OA machine such as a fax machine. It is configured as follows.

That is, the one-way clutch of the present invention has a hollow portion formed on the inner peripheral surface with a tapered portion having an inner diameter gradually reduced and a step formed at the inner diameter gradually decreasing end of the tapered portion to return to the inner diameter. A cylindrical outer ring, an inner ring that is rotatably inserted into the outer ring, and has a hollow cylindrical body whose opposite ends are closely opposed to each other through a gap in the circumferential direction, and at one end portion that is closely opposed with the gap interposed therebetween. A formed holding window, a roller disposed on the holding window, and protruding radially inward and outward from the holding window, and supporting the one end in the circumferential direction to which the roller is attached so as to be displaceable in the radial direction. A rotation shaft is inserted into the hollow portion of the inner ring to lock one rotation of the rotation shaft in one direction and idle the rotation in the other direction.

Further, in addition to the above-mentioned features, the one-way clutch of the present invention further comprises a means for supporting the one end in the circumferential direction so as to be displaceable in the radial direction. At least one axially provided on the opposite side
It is characterized by comprising a cut portion of a book.

[0013]

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

When the roller moves to the tapered portion which gradually reduces the inner diameter of the outer ring due to the accompanying movement of the inner ring due to the rotation of the rotating shaft, the roller is pushed radially inward by the tapered portion. One end in the circumferential direction of the inner ring holding this roller by the holding window is supported so as to be displaceable in the radial direction, so that the roller is displaced inward in the radial direction, thereby being pressed between the outer ring and the shaft. You. As a result, a strong frictional contact occurs between the rotating shaft and the inner peripheral surface of the inner ring, and as a result, the rotating shaft is connected to the outer ring via the inner ring to be in a locked state.

When the rotating shaft rotates in the opposite direction, the inner ring moves in the opposite direction, the roller moves away from the tapered portion of the outer ring, and the outer circumferential surface of the rotating shaft moves radially outward. , The one end in the circumferential direction is displaced radially outward to be released from the pressure between the outer ring and the rotating shaft. However, at the same time, the inner ring of the other end movement of the inner ring engages the stepped portion definitive on the gradually reducing inner diameter side end portion of the tapered portion is prevented. At this time, as described above, since the forced meshing force between the rotating shaft and the outer ring via the roller is released, there is almost no contact pressure between the rotating shaft and the inner ring, and the rotating shaft idles.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a one-way clutch according to the present invention. FIG. 1 shows a one-way clutch 10 according to one embodiment of the present invention. The one-way clutch 10 of this embodiment has 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 whose inner diameter gradually decreases and a step portion 13 which is relatively steep so as to return to the inner diameter of the outer ring 11 at an inner diameter gradually decreasing end of the tapered portion 12. ing.

The step 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 step portion 13 form the concave portion 14 so as to be partially crushed from the outer peripheral surface of the outer ring 11 by a machine or a tool such as a press machine. It can be easily formed by swelling the portion toward the inner peripheral surface. A hollow cylindrical inner ring 15 made of a synthetic resin is inserted into the outer ring 11 so as to be movable in the circumferential direction.

As shown in FIG. 2, the inner ring 15 is prevented from falling off in the axial direction by a flange portion 16 having both ends in the axial direction of the outer ring 11 bent inward in the radial direction. At this time, the portion where the flange portion 16 is formed corresponds to FIG.
As shown in the figure, the stepped portion 13 at the end portion on the inner diameter gradually decreasing side of the tapered portion 12 moves about 25
The portion extends from 0 degrees to 270 degrees.

Since the inner race 15 is made of synthetic resin as described above, it can be integrally molded. However, when this is structurally described, as shown in FIG. 3, a shaft used to be inserted into a hollow portion of the inner race 15 is used. That is, one axial slit 17 is formed at 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 open.

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

At this time, the holding window 18 is connected to the needle roller 1.
The inner peripheral surface has a width smaller than the diameter of the needle roller 19 so that the inner roller 9 does not fall inside. Two notches 2 extending in the axial direction are provided on the inner ring 15 on the side opposite to the edge of the circumferential one end 15a with the window 18 as a boundary.
0 and 21 are provided in a staggered manner. That is, one notch 20 is inserted 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 is parallel to one side from the other side. It is put up near.

Thus, the one end 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 mounted on the outer ring 11 while holding the needle roller 19, the needle roller 19 is mounted in a state where the gap between the cuts 20 and 21 is compressed. This will create a state that can be pressed by force. Further, as shown in FIG. 1, the inner peripheral surface and the outer peripheral surface of the circumferential one end 15 a are uniformly cut from the vicinity of the cut portion 20 to the edge of the circumferential one end 15 a. Thus, its thickness has been reduced.

Therefore, when an inner peripheral surface at one end 15a in the circumferential direction is fitted with a rotating shaft S, which will be described later, in the hollow portion of the inner ring 15, a space 22 is formed with respect to the rotating shaft S, and the outer peripheral surface is formed. A space 23 is also provided for the inner peripheral surface of the outer ring 11. The spaces 22, 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, so that the rotation shaft protrudes from the inner and outer peripheral surfaces of the inner ring 15 and is inserted into the hollow portion of the inner ring 15. S and the outer ring 11 are lightly contacted.

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

Thus, one end 15 of the inner race 15 in the circumferential direction is formed.
When the needle roller 19 held on the outer ring 11 reaches the tapered portion 12, the one end 15 a in the circumferential direction, which is supported so as to be displaceable in the radial direction, radially inward of the needle roller 19 due to the gradually decreasing slope of the inner diameter. As a result, the needle roller 19 is pressed between the rotation shaft S and the tapered portion 12 of the outer ring 11. Therefore, the contact friction between the rotation shaft S and the inner peripheral surface of the inner ring 15 increases, and the two are connected. Therefore, the rotation axis S is locked.

Conversely, when the rotating shaft S rotates rightward as viewed in FIG. 1, the rotating shaft S and the inner ring 15 are rotated as described above.
The inner ring 15 also moves rightward due to the light contact with the inner ring 15. As a result, the needle roller 19 is
From the rotating shaft S and the outer ring 11 to release the pressure. 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 on the inner diameter gradually decreasing end of the tapered portion 12, so that the relative movement with respect to the outer ring 11 is prevented. As a result, the contact friction force between the inner peripheral surface of the inner ring 15 and the rotating shaft S returns to a normal and extremely small state, and the rotating shaft S idles with respect to the inner ring 15.

As described above, when the rotation shaft S rotates in one direction, the rotation shaft S meshes with the outer ring 11 via the inner ring 15 to be in a locked state. On the other hand, when the rotation shaft S rotates in the other direction, the rotation shaft S and the outer ring 11 The connection is released by the movement of the inner race 15, and the rotation shaft S idles with respect to the inner race 15.
However, when assembling the inner ring 15 into the outer ring 11,
As shown in FIG. 1, the tapered portion 12 formed on the outer ring 11 must be fitted so that the maximum inner diameter gradually decreasing portion is located in the slit 17 of the inner ring 15.

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

In the above embodiment, if the needle roller 19 is made of stainless steel such as SUS, stainless steel or the like, there is no danger of rust or the like occurring at the rotating shaft contact portion, 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 anti-rust oiling.

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 tapered portion whose inner diameter gradually decreased 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 engagement force and a relatively small idling torque.

According to the one-way clutch of the present invention, since the locking is performed by increasing the frictional force with the rotating shaft by the eccentricity of the inner ring by one roller, it is not necessary to strictly regulate the shape accuracy of the roller contact portion. And the like.

[Brief description of the drawings]

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

FIG. 2 is a 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 race constituting the one-way clutch of the embodiment shown in FIG. 1;

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

FIG. 5 is a cross-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]

 DESCRIPTION OF SYMBOLS 10 One-way clutch 11 Outer ring 12 Inner diameter taper part 13 Step part 14 Recess 15 Inner ring 15a One circumferential end 15b The other circumferential end 16 Flange part 17 Slit 18 Holding window 19 Needle roller 20 Cut part 21 Cut part 22 Space 23 Space S Axis of rotation

Claims (2)

(57) [Claims] 1. A tapered portion having an inner diameter gradually reduced, and an end portion of the tapered portion which is gradually reduced in inner diameter is formed to return to the inner diameter .
A hollow cylindrical outer ring having a step formed on the inner peripheral surface, and an inner ring rotatably inserted into the outer ring and having a hollow cylindrical body whose two ends are closely opposed to each other in the circumferential direction through a gap. And a holding window formed at one end portion facing and opposed to the gap, the roller disposed on the holding window, protruding radially inward and outward from the holding window, and the roller was attached. Means for supporting one end in the circumferential direction so as to be displaceable in the radial direction, and inserting a rotating shaft into the hollow portion of the inner ring to lock one-directional rotation of the rotating shaft and idle in the other direction. A one-way clutch. Means for supporting one end in the circumferential direction so as to be displaceable in the radial direction, at least one at least one provided in the axial direction on the opposite side of the edge of the one end in the circumferential direction from the holding window. The one-way clutch according to claim 1, comprising a notch.