JP2013007412A - Spring-type unidirectional clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double spring type unidirectional clutch compact in an axial direction enhancing the durability and assemblability of clutch springs.SOLUTION: A large-diameter coil spring part 22 is provided to a clutch spring 21 incorporated within the drive gear 1, an interconnecting part 23 is provided to the distal coiled end of the large-diameter coil spring part, and a small-diameter coil spring part 24 wound in a different direction relative to the winding direction of the large-diameter coil spring part 22 is provided to the small-diameter end of the interconnecting part 23. The interconnecting part 23 of the clutch spring 21 has an inward spiral shape in which the winding direction is the same as the winding direction of the large-diameter coil spring part 22. When rotation torque is transmitted, the interconnecting part 23 will not be loaded at high stress, and the clutch spring will be more durable. An annular cover 31 is incorporated to block off an opening at the other end of the drive gear 1, the cover 31 being connected to the drive gear 1; and the cover 31, the clutch spring 21, and the drive gear 1 being formed as a single unit to facilitate assembly.

Description

  The present invention relates to a spring-type one-way clutch that transmits rotation of a drive member in one direction to a driven member.

  As a one-way clutch incorporated in a paper feed mechanism such as a printer, a copying machine, a facsimile, etc., a spring type that transmits and shuts off a one-way rotational torque by tightening and releasing a clutch spring has been conventionally known. It has been.

  As described in Non-Patent Document 1, the spring-type one-way clutch includes a single-spring type in which the clutch spring is single, and a double spring as described in Patent Document 1. There is a double spring type.

  Here, in the single-spring type one-way clutch, the spring is installed in one direction of the drive shaft as an assembly over the shaft ends of the drive shaft (drive arbor) and the driven shaft (driven arbor) arranged on the same axis. The rotation of the clutch spring reduces the diameter of the clutch spring, and the clutch spring tightens the drive shaft and the driven shaft to transmit the rotation of the drive shaft in one direction to the driven shaft. Since it is necessary to use a clutch spring having a large number of windings, there is a problem that the axial direction length of the one-way clutch becomes long and the size is increased.

  On the other hand, in the double spring type one-way clutch, the large-diameter coil spring portion of the double clutch spring is brought into elastic contact with the clutch surface formed on the inner periphery of the drive wheel, and the small-diameter coil spring portion is engaged. The assembly is elastically brought into contact with the clutch surface formed on the outer periphery of the driving wheel, and when the drive wheel rotates in one direction, the large-diameter coil spring portion is enlarged and the small-diameter coil spring portion is reduced in diameter. The diameter coil spring portion tightens the clutch surface of the driving wheel and the small diameter coil spring portion tightens the clutch surface of the driven wheel, thereby coupling the driving wheel and the driven wheel to generate a rotational torque in one direction of the driving wheel. Since the transmission torque capacity is large, a compact one-way clutch having an axial length can be obtained.

“Machine Element Utilization Manual / Spring”, Editor: NHK Spring, Nippon Kijo Co., Ltd., published on February 15, 1995 136

JP 2008-101740 A

  By the way, although the double spring type one-way clutch described in Patent Document 1 has a feature that the axial length can be reduced as described above, the clutch spring is a large-diameter coil spring. Part and small-diameter coil spring part are connected through a continuous part composed of a U-shaped reversing part that bends 180 °, so that each time rotation is transmitted from the drive wheel to the driven wheel, A relatively large stress is repeatedly applied to the reversal part having a small radius of curvature, and the stress is accumulated in the above-mentioned connecting portion, and the connecting portion is easily damaged by fatigue, and the durability of the clutch spring is improved. There are some points that need to be improved.

  In addition, since it is necessary to reduce the diameter of the large-diameter coil spring and incorporate the clutch spring into the drive wheel, expand the small-diameter coil spring portion of the clutch spring and assemble the driven wheel inside it, it is troublesome to assemble. Therefore, there is still a point to be improved in improving the assemblability.

  An object of the present invention is to improve the durability and assembly of a clutch spring in a double spring type one-way clutch that is compact in the axial direction.

  In order to solve the above-described problems, in the present invention, an outer member having an outer tube portion, and an inner tube portion provided on an inner surface of a flange portion facing inward from one end of the outer tube portion, An inner member that is inserted into the flange portion and arranged coaxially with the outer member; and a clutch spring that transmits and blocks rotational torque between the inner member and the outer member. A spring is provided with a continuous portion extending inwardly from the winding end of the large-diameter coil spring portion in the same winding direction as the large-diameter coil spring portion, and the large-diameter coil spring at the small-diameter end of the continuous portion A small-diameter coil spring part having a different winding direction from the part is connected, and the small-diameter coil spring part is arranged in the large-diameter coil spring part. The large-diameter coil spring part binds the outer diameter surface of the inner cylinder part. The small-diameter coil spring portion is incorporated to bind the cylindrical outer diameter surface of the inner member, and the opening at the other end of the outer member is closed by incorporating an annular lid, and the lid is closed to the outer member. In this way, a configuration in which the lid, the clutch spring, and the outer member are unitized is adopted.

  In the spring-type one-way clutch configured as described above, one of the outer member and the inner member is a drive side, and the other is a driven side. Now, when the outer member is the driving side and the outer member is rotated in the direction opposite to the winding direction of the large-diameter coil spring portion, the large-diameter coil spring portion is reduced in diameter and the outer-diameter surface of the inner cylinder portion is reduced. The large-diameter coil spring portion rotates together with the outer member, and the rotation is transmitted to the small-diameter coil spring portion via the connecting portion.

  At this time, since the winding direction of the large-diameter coil spring portion and the small-diameter coil spring portion is different, the small-diameter coil spring portion has a reduced diameter and strongly tightens the cylindrical outer diameter surface of the inner member. Is transmitted to the inner member via the clutch spring, and the inner member rotates in the same direction as the outer member.

  On the other hand, when the outer member is rotated in the winding direction of the large-diameter coil spring portion, the small-diameter coil spring is applied when the binding force of the large-diameter coil spring portion is stronger than that of the small-diameter coil spring. The diameter of the portion increases, slip occurs at the contact portion between the small-diameter coil spring portion and the inner member, the rotation of the outer member is not transmitted to the inner member, and the outer member idles.

  Here, when the rotational torque is transmitted from the outer member to the inner member, a stress corresponding to the transmitted torque is applied to the connecting portion of the clutch spring. At this time, since the continuous portion extends inwardly from the winding end of the large-diameter coil spring portion with the same winding direction as the large-diameter coil spring portion rotating together with the outer member, There is no such thing as being stressed locally. For this reason, the continuous portion is not damaged by fatigue.

  In the spring-type one-way clutch according to the present invention, a spiral groove portion that can accommodate a continuous portion of the clutch spring is provided at the distal end portion of the inner cylinder portion, and the cover body is fitted into the distal end portion of the inner cylinder portion. By providing the cylindrical portion, the tip portion which is the free end of the inner cylindrical portion can be supported by the supporting cylindrical portion, thereby increasing the bending rigidity of the inner cylindrical portion, preventing deformation and breakage of the inner cylindrical portion, The inner cylinder part can be securely bound by the reduced diameter of the large-diameter coil spring part. As a result, slippage due to contact between the inner tube portion and the large-diameter coil spring portion can be prevented, and torque can be reliably transmitted between them.

  In addition, an annular engagement groove is provided on one of the outer diameter surface of the support cylinder portion and the inner diameter surface of the tip end portion of the inner cylinder portion, and an engagement convex portion that is engaged with the engagement groove is formed on the other side. By connecting the body and the outer member, the front end of the support cylinder is fitted into the front end of the inner cylinder, and the lid is pushed toward the inner cylinder to engage the engagement protrusion into the engagement groove. And the lid can be easily connected to the outer member.

  Further, the inner diameter surface of the flange portion and the inner diameter surface of the lid body are radial bearing surfaces that relatively rotatably support the outer member and the inner member, so that the outer member and the inner member are accurately relative to each other. Can be rotated.

  In addition, when a hook piece is provided at the winding start end of the large-diameter coil spring portion of the clutch spring, and the hook piece is locked to the outer cylinder portion of the outer member, the outer member can be used as a drive side in use. The rotation of the side member can be reliably transmitted to the large-diameter coil spring portion. Further, when the rotation transmission from the outer member to the inner member is interrupted, the small diameter coil spring portion and the cylindrical outer diameter surface contact portion of the inner member can be caused to slip, and the sliding portion can be specified. it can.

  For this reason, when the outer member is formed of a synthetic resin molded product and has a lower hardness than the inner member made of metal, the outer member having a lower hardness is prevented from being worn by contact with the clutch spring. Can do.

  As described above, when each of the outer member and the lid is a synthetic resin molded product and is lower than the hardness of the inner member made of metal, the large-diameter coil spring portion has a small binding force to tighten the inner cylinder portion. If the coil spring part is made stronger than the binding force for tightening the inner member, the contact between the small diameter coil spring part and the inner member is the same as when the hook piece part is locked to the outer cylinder part when torque transmission is interrupted. Slip can be caused at the portion, and wear of the outer member can be suppressed.

  Here, an engagement groove extending in the axial direction from the other end surface of the outer cylinder portion is formed on the inner diameter surface of the outer cylinder portion, and the hook piece portion is engaged with the engagement groove so that the outer cylinder portion Since the hook piece portion can be engaged with the engagement groove when the clutch spring for fitting the large-diameter coil spring portion to the radial surface is assembled, the assembly of the clutch spring can be facilitated.

  In addition, if a large-diameter recess is provided in which the lid is fitted at the other end opening of the outer cylinder, the inside of the outer cylinder can be completely sealed, and the grease sealed inside leaks to the outside. In addition, it is possible to effectively prevent foreign matters from entering from the outside to the inside.

  When the inner member is the drive side, when the inner member is rotated in the direction opposite to the winding direction of the small-diameter coil spring portion, the small-diameter coil spring portion is reduced in diameter so that the cylindrical outer diameter surface of the inner member is reduced. The small diameter coil spring portion is rotated together with the inner member. The rotation is transmitted to the large-diameter coil spring portion through the continuous portion, and the large-diameter coil spring portion is reduced in diameter to strongly tighten the outer diameter surface of the inner cylinder portion, and the rotation of the inner member is performed via the clutch spring. The outer member is transmitted to the outer member, and the outer member rotates in the same direction as the inner member.

  Even in this case, the stress is not locally applied to the continuous portion of the clutch spring, and the continuous portion is not damaged by fatigue.

  In the present invention, as described above, the large-diameter coil spring portion and the small-diameter coil spring portion disposed inside thereof and having a winding direction different from that of the large-diameter coil spring portion are separated from the winding end of the large-diameter coil spring portion. By providing a continuous portion extending in an inward spiral, it is possible to prevent local stress from being applied to the continuous portion during transmission of rotational torque between the outer member and the inner member. Can do. For this reason, it is extremely less likely that the continuous portion is damaged due to fatigue, and the durability of the clutch spring can be improved.

  Further, the opening at the other end of the outer member is closed by incorporating an annular lid, the lid is connected to the outer member, and the lid, the clutch spring, and the outer member are unitized, so that the clutch By inserting the end of the inner member into the small-diameter coil spring portion of the spring and rotating the inner member in the axial direction while pushing the inner member in the axial direction, the small-diameter coil spring portion expands in diameter, Since the inner member can be incorporated into the small-diameter coil spring portion, the one-way clutch can be incorporated very easily.

  Furthermore, since the opening at the other end of the outer member can be closed by incorporating the lid, the leakage of the grease sealed between the opposing portions of the outer member and the inner member is prevented, and from the outside It is possible to prevent foreign matter from entering the inside.

The longitudinal cross-sectional view which shows embodiment of the spring type one-way clutch which concerns on this invention Sectional view along the line II-II in FIG. Longitudinal sectional view of unit product consisting of outer member, clutch spring and lid Partially cutaway perspective view showing drive gear Front view of clutch spring Sectional view along line VI-VI in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the spring type one-way clutch includes a unit product A and a rotating shaft 41 as an inward member assembled in the unit product A.

  As shown in FIG. 3, the unit product A includes a drive gear 1 as an outer member, a clutch spring 21 incorporated in the drive gear 1, and the clutch spring 21 connected to the drive gear 1. It consists of a lid body 31 to prevent it from being removed.

  As shown in FIGS. 3 and 4, the drive gear 1 has an outer cylinder portion 2, and a large number of teeth 3 are formed in the circumferential direction on the outer diameter surface of the outer cylinder portion 2. An inward flange portion 4 is formed at one end of the outer cylinder portion 2, and an inner diameter surface of the flange portion 4 is a radial bearing surface 5 that rotatably supports the rotating shaft 41. Further, the flange portion 4 is formed with an inner cylinder portion 6 on the inner surface thereof, and the inner cylinder portion 6 and the outer cylinder portion 2 are arranged coaxially.

  As shown in FIG. 3, a large-diameter concave portion 8 is formed in the other end opening of the outer cylinder portion 2. The aforementioned lid 31 is fitted into the large-diameter recess 8, and the annular space 7 formed between the outer diameter surface 6 a of the inner cylinder portion 6 and the inner diameter surface 2 a of the outer cylinder portion 2 is closed by the lid body 31. Has been.

  The lid body 31 has an annular shape, and a support cylinder portion 32 formed on the inner peripheral portion thereof is fitted into the distal end portion of the inner cylinder portion 6 to support the distal end portion of the inner cylinder portion 6. The inner diameter surface of the support cylinder portion 32 is a radial bearing surface 33 that rotatably supports the rotary shaft 41.

  An engagement convex portion 34 having a semicircular cross section is formed on the outer diameter surface of the support cylinder portion 32. The engaging convex portion 34 engages with an annular engaging groove 9 having a semicircular cross section formed on the inner diameter surface of the distal end portion of the inner cylinder portion 6, and the lid body 31 is prevented from being pulled out by the engagement. Is connected to

  In addition, an engagement groove may be formed in the support cylinder part 32, and an engagement convex part may be provided in the inner cylinder part 6.

  Here, in the embodiment, the drive gear 1 and the lid body 31 are formed of a synthetic resin, but the material is not limited to the synthetic resin and may be a metal.

  As shown in FIGS. 5 and 6, the clutch spring 21 includes a large-diameter coil spring portion 22, an inward spiral-shaped continuous portion 23 that is continuously provided at the winding end of the large-diameter coil spring portion 22, and The small-diameter coil spring portion 24 is arranged on the inside of the large-diameter coil spring portion 22 so as to be continuous with the small-diameter end of the continuous portion 23, and outwards at the winding start end of the large-diameter coil spring portion 22. A hook piece 25 is formed.

  Here, the winding directions of the large-diameter coil spring portion 22 and the small-diameter coil spring portion 24 are different. In the embodiment, the large-diameter coil spring portion 22 is clockwise and the small-diameter coil spring portion 24 is counterclockwise, and the winding direction of the spiral continuous portion 23 is the same as the winding direction of the large-diameter coil spring portion 22. ing.

  As shown in FIGS. 1 to 3, the clutch spring 21 is incorporated so that the continuous portion 23 is accommodated in the spiral groove portion 10 formed at the tip portion of the inner cylinder portion 6. In addition, the clutch spring 21 has a large-diameter coil spring portion 22 that binds to the outer-diameter surface 6 a of the inner cylinder portion 6, and a small-diameter coil spring portion 24 that binds to the cylindrical outer-diameter surface 41 a of the rotating shaft 41. A hook piece portion 25 provided at the winding start end of the spring portion 22 is incorporated into an axial engagement groove 11 formed on the inner diameter surface of the outer cylinder portion 2 of the drive gear 1.

  In the spring-type one-way clutch configured as described above, when the drive gear 1 is rotated in the direction opposite to the winding direction of the large-diameter coil spring portion 22, as shown by the arrow in FIG. The diameter is reduced and the outer diameter surface 6 a of the inner cylinder portion 6 is further tightened, and the large-diameter coil spring portion 22 rotates together with the drive gear 1. The rotation is transmitted to the small-diameter coil spring portion 24 through the continuous portion 23.

  At this time, since the winding direction of the large-diameter coil spring portion 22 and the small-diameter coil spring portion 24 is different, the small-diameter coil spring portion 24 is reduced in diameter and tightens the outer diameter surface 41 a of the rotating shaft 41. Therefore, the rotation of the drive gear 1 is transmitted to the rotation shaft 41 via the clutch spring 21, and the rotation shaft 41 rotates in the same direction as the drive gear 1.

  When the rotational torque is transmitted from the drive gear 1 to the rotating shaft 41, the connecting portion 23 of the clutch spring 21 is loaded with a stress corresponding to the transmitted torque. At this time, the connecting portion 23 is assumed to be the same as the winding direction of the large-diameter coil spring portion 22 that rotates together with the drive gear 1 and extends inwardly from the winding end of the large-diameter coil spring portion 22. There is no case where stress is locally applied to the installation portion 23. Further, since the stress applied to the continuous portion 23 is received by the inner surface of the spiral groove portion 10, the continuous portion 23 is not damaged by fatigue.

  On the other hand, when the drive gear 1 is rotated in the opposite direction to the direction indicated by the arrow in FIG. 2 (the same direction as the winding direction of the large-diameter coil spring portion 22), the rotation is greatly increased from the hook piece portion 25. The rotation of the large-diameter coil spring portion 22 is transmitted to the small-diameter coil spring portion 24 via the connecting portion 23 and the small-diameter coil spring portion 24 is expanded in diameter. Due to the expanded diameter, slip occurs at the contact portion between the small-diameter coil spring portion 24 and the outer diameter surface 41a of the rotating shaft 41, and the rotation of the driving gear 1 is not transmitted to the rotating shaft 41, and the driving gear 1 rotates idle.

  As described above, when the rotation transmission is interrupted, the clutch spring 21 slips at the contact portion with the rotating shaft 41 having a high hardness, so that the inner cylinder portion 6 of the driving gear 1 having a low hardness is worn. There is no.

  As in the spring type one-way clutch shown in the embodiment, when each of the drive gear 1 and the lid 31 is a synthetic resin molded product and is lower in hardness than the rotating shaft 41 made of metal, the large-diameter coil spring portion If the tightening force for tightening the inner cylindrical portion 6 is made stronger than the tightening force for the small-diameter coil spring portion 24 tightening the rotating shaft 41, the contact portion between the small-diameter coil spring portion 24 and the rotating shaft 41 is blocked when torque transmission is interrupted. Slip can be caused and wear of the inner cylinder part 6 can be prevented.

  In the spring-type one-way clutch according to the embodiment, as shown in FIG. 3, an annular lid 31 is incorporated in the large-diameter recess 8 formed in the other end opening of the drive gear 1, and the lid 31 is assembled. The lid 31 is connected to the drive gear 1 by the engagement of the engagement convex portion 34 on the outer diameter surface of the formed support cylinder portion 32 and the engagement groove 9 of the inner cylinder portion 6, so that the drive gear 1 and the clutch spring 21 are connected. Since the cover 31 is unitized, the end of the rotary shaft 41 is inserted into the small-diameter coil spring portion 24 of the clutch spring 21, and the winding direction of the small-diameter coil spring portion 24 is pushed in the axial direction. The small-diameter coil spring portion 24 is expanded by contact with the rotary shaft 41, and the rotary shaft 41 can be incorporated into the small-diameter coil spring portion 24. For this reason, the one-way clutch can be incorporated very easily.

  Further, since the opening of the other end of the drive gear 1 is closed by the incorporation of the lid 31, the leakage of the grease sealed inside the drive gear 1 is prevented and foreign substances from the outside to the inside are prevented. Intrusion can be prevented.

A Unit product 1 Drive gear (outer member)
2 outer cylinder part 4 flange part 5 radial bearing surface 6 inner cylinder part 6a outer diameter surface 8 large diameter recessed part 9 engaging groove 10 spiral groove part 11 engaging groove 21 clutch spring 22 large diameter coil spring part 23 connecting part 24 small diameter coil Spring part 25 Hook piece part 31 Cover body 32 Support cylinder part 33 Radial bearing surface 34 Engaging convex part 41 Rotating shaft (inner member)
41a outer diameter surface

Claims (8)

  An outer member having an outer cylindrical portion, an outer member having an inner cylindrical portion provided on an inner surface of the flange portion facing inward from one end of the outer cylindrical portion, and being inserted into the flange portion and coaxial with the outer member An inner member that is disposed, and a clutch spring that transmits and blocks rotational torque between the inner member and the outer member, and the clutch spring extends from a winding end of the large-diameter coil spring portion. A continuous portion extending inwardly with the same winding direction as that of the large-diameter coil spring portion is provided, and a small-diameter coil spring portion having a winding direction different from that of the large-diameter coil spring portion is continuously provided at the small-diameter end of the continuous portion. The small-diameter coil spring portion is arranged in the large-diameter coil spring portion, the large-diameter coil spring portion binds the outer diameter surface of the inner cylinder portion, and the small-diameter coil spring portion is a cylinder of the inner member. The outer diameter surface is tightly integrated, the opening at the other end of the outer member is closed by incorporating an annular lid, the lid is connected to the outer member, and the lid, clutch spring, and outer Spring-type one-way clutch with unitized members.   A spiral groove portion is provided at the distal end portion of the inner cylinder portion so as to accommodate the continuous portion of the clutch spring, and the lid body is fitted into the distal end portion of the inner cylinder portion, and the distal end portion of the inner cylinder portion The spring-type one-way clutch according to claim 1, further comprising a support cylinder portion that supports the spring.   An annular engagement groove is provided on one of the outer diameter surface of the support cylinder portion and the inner diameter surface of the tip end portion of the inner cylinder portion, and an engagement convex portion that is engaged with the engagement groove is formed on the other side. The spring type one-way clutch according to claim 2, wherein the outer member and the outer member are connected.   The spring according to any one of claims 1 to 3, wherein an inner diameter surface of the flange portion and an inner diameter surface of the lid body are radial bearing surfaces that relatively rotatably support the outer member and the inner member. Formula one-way clutch.   The large-diameter coil spring portion of the clutch spring has a hook piece portion at a winding start end, and the hook piece portion is locked to an outer cylinder portion of the outer member. A spring-type one-way clutch described in 1.   The spring-type one according to claim 5, wherein an engagement groove extending in an axial direction from the other end surface of the outer cylinder portion is formed on an inner diameter surface of the outer cylinder portion, and the hook piece portion is engaged with the engagement groove. Direction clutch.   2. The outer member and the lid are each formed of a synthetic resin, and the binding force for tightening the inner cylinder portion by the large-diameter coil spring portion is stronger than the binding force for tightening the inner member by the small-diameter coil spring portion. The spring-type one-way clutch according to any one of Items 5 to 5.   The spring type one-way clutch according to any one of claims 1 to 7, wherein a large-diameter concave portion is provided in the other end opening of the outer cylinder portion, and the lid is fitted in the large-diameter concave portion.

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