JP2006029558A - One-way clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-way clutch, in which assembling work or adjusting work can be easily conducted by prohibiting lock action in a stop state. <P>SOLUTION: Pockets 26 having a wedge angle θ are provided in weights 4 and 4 of a centrifugal clutch. When an inner member 2 is in the stop state, a roller 7 contained in the pocket 26 becomes free. When the inner member 2 is rotated in the opposite direction to the wedge angle at prescribed rotation speed or faster, the roller 7 is locked to transmit torque. When it is rotated in the direction of the wedge angle θ, it becomes free to disconnect transmission of torque. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a one-way clutch used in a driving unit such as a paper feeding unit of a printer or a copying machine, and facilitates the assembling work.

  One-way clutches conventionally used in office machines such as printers and copiers are such that an internal member is rotatably fitted to an external member, and a cam surface inclined in a certain rotational direction is formed on the outer diameter surface of the internal member. A pocket having a pocket is provided and a roller is accommodated in the pocket, and the roller is engaged and locked by a relative rotation of the internal member and the external member to transmit torque, and the roller is rotated by rotation in the opposite direction. The transmission of torque is cut off to prevent transmission (Patent Document 1).

Moreover, as a clutch generally known conventionally, there exists a centrifugal force clutch using the centrifugal force which acts on a pair of weight attached to the internal member (nonpatent literature 1). This clutch does not function as a clutch in a stopped state, the outer member can freely rotate with respect to the inner member, and the weight is pressed against the inner diameter surface of the outer member only when the rotation speed exceeds a certain value, and torque is transmitted. It has come to be.
Japanese Patent No. 3270667 "Mechanical motion mechanism" 1987, Gihodo Publishing Co., Ltd. (1106 "Centrifuge Force Clutch (1)"

  Since the one-way clutch functions as a clutch depending on the rotation direction regardless of the rotation speed, the one-way clutch can rotate only in one direction without rotating in the lock direction even when the apparatus is stopped. For this reason, there is a problem that workability is poor because the device does not rotate in the locking direction when the device using the one-way clutch is assembled, or when alignment is performed by hand after assembly. Further, in the case of the centrifugal clutch described above, the torque can be transmitted to the driven side when the rotational speed exceeds a certain rotational speed. When a change occurs, particularly when the speed changes to the low speed side, there is a problem that smooth rotation on the driven side cannot be obtained.

  SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to be free in any rotation direction in a stopped state, so that it does not interfere with assembly work and the like and can reliably exert a clutch function at a low rotation speed. .

  In order to achieve the above object, the present invention provides an external member, an internal member rotatably supported inside the external member, and a rotational axis of the internal member parallel to a centrally symmetric position of the internal member. In a clutch comprising a weight attached to a shaft and transmitting the torque by pressing the weight against the inner diameter surface of the external member by a centrifugal force accompanying the rotation of the internal member above a certain rotational speed. Each of the weights has a pocket that accommodates a roller on a surface facing the inner diameter surface of the external member, and each pocket has a cam surface inclined toward one direction of rotation on the bottom surface, and the cam surface and the inner diameter A wedge angle is formed between the roller and the roller stored in the pocket is free when the internal member is in a stopped state, and the internal member has a constant rotational speed in a direction opposite to the wedge angle. Times beyond When the said rollers are torque transmission performed locked, when rotated in the direction of the wedge angle in the opposite configured as transmission of torque in a free is interrupted.

  According to the above configuration, when the internal member is in the stopped state, the external member or the exterior body integrated with the external member can be freely rotated in either the left or right direction by applying a force such as a hand. Also, when the internal member rotates at a certain rotation speed or more, the roller is pressed by the centrifugal force acting on the weight, and when the rotation direction is opposite to the wedge angle, the roller is caught and locked. Torque is transmitted. When the rotation direction is the reverse direction, the rollers are free and torque transmission is interrupted.

  In addition, it is desirable to take the structure which provided the said pocket close to the attaching part of the said weight. If comprised in this way, since the pressing force exerted on a roller via a weight will become large, even when a rotational speed is low, a reliable clutch action can be performed.

  In addition, when the centrifugal force acting on the weight is insufficient, a C-shaped spring is mounted around the rotation shaft of the internal member, and the C-shaped spring is pressed against the inner surface of each weight so as to be radially outward. It is desirable to adopt a configuration in which a pressing force in the direction is applied and the pressing force is set to a size that does not hinder the rotation of the internal member and the weight integrally therewith. According to this configuration, the spring force of the C-shaped spring can compensate for the lack of centrifugal force and can reliably function as a torque limiter.

  As described above, the one-way clutch according to the present invention has an effect of facilitating assembly work and manual adjustment work of the position of each part and the like because the clutch function does not work when the device is in a stopped state. In addition, by adopting a configuration in which the position of the pocket is close to the attachment part of the weight, or a configuration in which centrifugal force is assisted by a C-shaped spring, the clutch function is reliably exhibited even in the low-speed rotation range. In addition, the entire product can be reduced in size and weight.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

Embodiment 1
The one-way clutch of the first embodiment shown in FIGS. 1 to 4 includes an external member 1, an internal member 2 rotatably supported in the external member 1, and a pair of internal members 2 attached to the internal member 2. It consists of weights 4 and 4, a lid 5 of the external member 1, an exterior body 6 (in the illustrated case, a roller with a collar), rollers 7 and the like.

  The external member 1 is formed in a cylindrical shape (see FIG. 3), and a plurality of axial grooves 8 are formed on the outer peripheral surface. The external member 1 is fitted into the exterior body 6, and the same number of protrusions 10 formed on the inner diameter surface of the exterior body 6 are fitted into the groove 8 and integrated. One end of the outer package 6 is closed by the end wall 9, and the lid 5 is fitted to the open end of the other end. One end surface of the external member 1 is integrated with the end wall 9 and the other end surface is in contact with the inner surface of the lid 5. Shaft holes 12 and 13 are provided at the centers of the end wall 9 and the lid 5.

  The inner member 2 is a plate-like member having a required thickness that is slightly shorter than the inner diameter of the outer member 1, and a boss 15 having a shaft hole 14 is provided at the center portion, and the shaft holes 12, 13, 14 are provided. A shaft 16 inserted through the shaft is rotatably supported inside the external member 1, and a D-cut 17 is applied to the shaft hole 14 so as to rotate integrally with the shaft 16. Notched step portions 18 and 18 are provided on the left and right side portions of the upper and lower end portions of the internal member 2, and a bearing piece 19 is provided on each notch step portion 18 so as to protrude in opposite directions at both the upper and lower end portions (see FIG. 4). .

  The weights 4, 4 have the same weight and are symmetrical with respect to the center of the shaft 16, and are disposed on both sides of the inner member 2. Each weight 4 has a semi-cylindrical outer peripheral surface 21 and inner side surfaces 22, 22 facing the inner member 2, and faces the boss 15 with a predetermined interval between both inner side surfaces 22, 22. An arc surface 23 is provided. A mounting portion 24 is provided at one end of the outer peripheral surface 21, the mounting portion 24 is fitted between the bearing pieces 19, 19, and the weight 4 is attached to the internal member 2 by a pair of pins 25 parallel to the shaft 16. On the other hand, it can be freely rotated. Each pair of pins 25 for attaching the two weights 4 and 4 is disposed at a symmetrical position with respect to the center of the shaft 16 as shown in FIG.

  Pockets 26 opened at both end surfaces of the weight 4 are provided on the outer peripheral surface 21 close to the mounting portion 24, and the rollers 7 are accommodated in the pockets 26. The pocket 26 is provided with a cam surface 27 on the bottom surface. This cam surface 27 has a wedge angle θ that becomes narrower toward the pin 25 side with respect to a tangent drawn at the contact point of the inner diameter surface of the outer member 1 in the locked state of the roller 7 (see FIG. 5A). The roller 7 becomes free when it moves in the direction opposite to the wedge angle θ in the pocket 26 (see FIGS. 1A and 1B), and conversely locks when it moves in the direction of the wedge angle θ (FIGS. 5A and 5B). )reference). The pocket 26 is preferably provided at a position as close as possible to the mounting portion 24 in order to maximize the pressing force of the roller 7 accommodated therein against the inner diameter surface of the outer member 1.

  A spring support pin 28 is provided at an end portion (that is, a free end portion) opposite to the mounting portion 24 of each weight 4, and the other weight 4 facing the spring support pin 28 is connected to the pin 25 of the other weight 4. A coil spring 29 is interposed therebetween. The coil spring 29 presses the inner side surfaces 22 and 22 of each weight 4 against the internal member 2 by pulling the free end portion of each weight 4 toward the mounting portion 24 side of the other weight 4 with a predetermined spring force. At the same time, a constant gap is formed between the outer peripheral surface 21 and the inner diameter surface of the external member 1.

  The spring force of the coil spring 29 is set to be smaller than a predetermined centrifugal force acting on the weights 4 and 4.

  The one-way clutch of the first embodiment is as described above, and when the internal member 2 is in a stopped state, the weights 4 and 4 are internal members as shown in FIGS. Pulled to the second side, the roller 7 is in a free state. Therefore, in this state, the external member 1 and the exterior body 6 integrated therewith can freely rotate in both directions (see arrows A and B).

  Further, when the internal member 2 rotates at a certain rotational speed or more, the coil spring 29 is stretched by the centrifugal force acting on the weights 4, 4, and each weight 4 approaches the inner diameter surface of the external member 1. When the rotation direction of the internal member 2 is the direction opposite to the wedge angle θ (see arrow a in FIG. 5A), the roller 7 is engaged and locked, and the external member 1 and the exterior body 6 are locked. Torque is transmitted (see arrow A in FIG. 5A). In this case, when the exterior body 6 is rotated from the load side and becomes larger than the rotation speed of the internal member 2, the lock is released and the transmission of torque is interrupted.

  Conversely, when the internal member 2 rotates in the direction of the wedge angle θ (see arrow b), the rollers 7 are in a free state and the transmission of torque is interrupted.

[Embodiment 2]
In the case of the first embodiment described above, this is a form used when a centrifugal force sufficient to lock the roller 7 is generated by the rotation of the internal member 2. However, when such a large centrifugal force cannot be obtained due to the rotational speed, the weight of the weight 4, etc., a structure as shown in FIG. In other words, in this case, holes 31 and 31 are provided at two locations on the internal member 2 across the boss 15 of the internal member 2, and a C-shaped spring 32 is passed through the holes 31 and 31 with a margin. In a state where the diameter is slightly reduced, it is pressed against the arc surfaces 23 and 23 of the weights 4 and 4, and a pressing force radially outward is applied to each weight 4. The pressing force is added to the centrifugal force accompanying the rotation of the internal member 2 to compensate for the lack of centrifugal force.

  In this case, the coil spring 29 used in the first embodiment is not used, but this is because the spring force of the coil spring 29 works in the direction to cancel the centrifugal force acting on the weight 4. This is because sufficient centrifugal force can be obtained by avoiding the above. For this reason, in a stopped state, the roller 7 falls into the deepest part of the pocket 26, and the weight 4 may come into contact with the inner diameter surface of the external member 1, but the internal member 2 is prevented from rotating by friction at the contact part. The spring force of the C-shaped spring 32 is selected to such an extent that there is not. Other structures are the same as those in the first embodiment.

  Since the one-way clutch of the second embodiment is as described above, when the internal member 2 is in a stopped state, the exterior body 6 can rotate in either the left or right direction integrally with the external member 1 (FIG. 6 ( c)). Further, when the inner member 2 rotates in the direction of arrow a, the roller 7 is locked, torque is transmitted, and the exterior body 6 rotates in the direction of arrow A (see FIG. 6A). When it is rotated from the load side and becomes larger than the rotation speed of the internal member 2, the lock is released and torque transmission is interrupted. Conversely, when the internal member 2 rotates in the direction of the arrow b, the rollers 7 are in a free state, and torque transmission is interrupted. These actions are the same as in the first embodiment.

(A) Sectional view at the time of stop of Embodiment 1, (b) Partially enlarged sectional view of the same as above (A) Sectional view taken along line XX in FIG. 1 (a), (b) Sectional view taken along line YY in FIG. 1 (a) Exploded perspective view of Embodiment 1 Partially enlarged exploded perspective view of the above (A) Cross-sectional view during rotation, (b) Partially enlarged cross-sectional view. (A) Sectional view at the time of rotation of Embodiment 2, (b) Partial perspective view of the above, (c) Partially enlarged sectional view at the time of stopping

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 External member 2 Internal member 4 Weight 5 Lid 6 Exterior body 7 Roller 8 Groove 9 End wall 10 Rib 12 Shaft hole 13 Shaft hole 14 Shaft hole 15 Boss 16 Shaft 17 D cut 18 Notch step part 19 Bearing piece 21 Outer periphery Surface 22 Inner surface 23 Arc surface 24 Mounting portion 25 Pin 26 Pocket 27 Cam surface 28 Spring support pin 29 Coil spring 31 Hole 32 C-shaped spring

Claims (3)

  An external member, an internal member rotatably supported inside the external member, and a weight attached to a centrally symmetric position of the internal member with an axis parallel to the rotation axis of the internal member, In the clutch that transmits the torque by pressing the weight against the inner diameter surface of the external member by a centrifugal force accompanying the rotation of the internal member at a certain rotational speed or more, facing the outer member inner diameter surface of each weight Each surface is provided with a pocket storing a roller, and each pocket has a cam surface inclined in one direction of rotation on its bottom surface and forms a wedge angle between the cam surface and the inner diameter surface, The roller stored in the pocket is free when the internal member is in a stopped state, and the roller locks and torques when the internal member rotates in a direction opposite to the wedge angle beyond a certain rotational speed. of Reaches is performed, the one-way clutch, characterized in that contrary to become free when rotated in the direction of the wedge angle transmission of torque is interrupted.   The one-way clutch according to claim 1, wherein the pocket is provided close to an attachment portion of the weight.   A C-shaped spring is mounted around the rotation axis of the internal member, and the C-shaped spring is pressed against the inner surface of each weight to apply a radially outward pressing force. The one-way clutch according to claim 1, wherein the one-way clutch is set to a size that does not prevent rotation of the weight integrally formed therewith.

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