JP2008157395A - Electromagnetic spring clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic spring clutch of a particularly low profile type, increasing friction torque on the friction face of an armature and miniaturizing an electromagnetic coil. <P>SOLUTION: The electromagnetic spring clutch 1 comprises a first rotating shaft 2 formed in a double cylindrical shape with an outer cylinder portion 2a and an inner cylinder portion, where a connection portion 2b is provided at one end for connecting the outer cylinder portion 2a to the inner cylinder portion and an opening portion is provided at the other end. The outer cylinder portion 2a is inserted through a field core 11 and borne by the field core 11, and the inner cylinder portion is rotatably inserted through a second rotating shaft 3. A coil spring 7 connecting the first rotating shaft 2 to the second rotating shaft 3 for transmitting rotating force has one end entering into a hollow portion between the outer cylinder portion 2a and the inner cylinder portion. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electromagnetic spring clutch, and more particularly to an electromagnetic spring clutch that transmits or does not transmit an input rotational force to an output shaft via a coil spring by energizing or de-energizing an electromagnetic coil.

  In office automation equipment such as printers and copiers, for example, an electromagnetic spring clutch is incorporated in a mechanism portion for transporting paper and the like, and has a function of transmitting / not transmitting transport power and the like.

  Here, there exists the electromagnetic spring clutch 100 of patent document 1 as an example of the conventional electromagnetic spring clutch (FIG. 4). In the electromagnetic spring clutch 100, when the electromagnetic coil 110 is energized, the armature 138 moves and abuts against the abutting portion, and the armature 138 is braked, whereby the coil spring 140 is wound and the first spring is wound. When the rotating shaft 126 and the second rotating shaft 134 are rotated together and the electromagnetic coil 110 is not energized, the armature 138 is separated from the contact portion, the braking is released, and the coil spring 140 is wound. The tightening is loosened to release the integrated rotation of the first rotating shaft 126 and the second rotating shaft 134.

JP 2002-31161 A

However, in the above-described conventional electromagnetic spring clutch, a part of the field core 116 is formed in the bearing portion 122 that supports the first rotating shaft 126, and the bearing portion 122 and the coil spring 140 are arranged side by side on the same axis. are arranged, since the bearing portion 122 needs a certain length, the longer the axial length L _0, there is a problem that thinning is difficult. In addition, since the end face of the cylindrical armature 138 is abutted against the contact portion 142, a sufficient braking force cannot be obtained and a large amount of electric power is required.

  The present invention has been made in view of the above circumstances, and provides a particularly thin electromagnetic spring clutch, as well as an electromagnetic spring clutch capable of increasing the friction torque on the armature friction surface and reducing the size of the electromagnetic coil. With the goal.

  The present invention solves the above-described problems by the solving means described below.

  An electromagnetic spring clutch according to the present invention includes a ring-shaped field core having a ring-shaped cross section, an electromagnetic coil built in the field core, and a first rotatably supported through the field core. A first rotary shaft, a second rotary shaft that is coaxial with the first rotary shaft and rotatably supported on the first rotary shaft, and is rotatably provided on the second rotary shaft; A flange-like member extending in a flange shape in a direction opposite to the end face of the field core, an input hub provided on the second rotating shaft, and an armature provided on a surface of the flange-like member facing the field core; A coil spring having one end connected to the first rotating shaft and the other end locked to the collar-shaped member, and the field core and the armature are energized by energizing or de-energizing the electromagnetic coil. An electromagnetic spring clutch in which the coil spring is wound or released by being attracted or dissociated to connect or release the first rotating shaft and the second rotating shaft. The rotating shaft is provided with an outer cylinder part and an inner cylinder part, a connecting part for connecting the outer cylinder part and the inner cylinder part is provided on one end side, and is formed in a double cylinder shape having an opening part on the other end side. The outer cylinder part is inserted through the field core and is supported by the field core, the inner cylinder part is rotatably inserted through the second rotating shaft, and the coil spring has one end side. It has entered into the hollow part between the said outer cylinder part and the said inner cylinder part, It is characterized by the above-mentioned.

  The coil spring is formed to have an outer diameter smaller than the inner diameter of the outer cylinder portion, and is formed to have an inner diameter smaller than the outer diameter of the inner cylinder portion and the outer diameter of the second rotating shaft, The inner cylinder portion and the outer peripheral portion of the second rotating shaft are fitted.

  In addition, the hollow portion is formed to have a depth over almost the entire width of the ring portion of the field core.

  According to the first and second aspects, in the conventional electromagnetic spring clutch, the bearing portion and the coil spring are configured to be arranged side by side in the axial direction, whereas the electromagnetic spring clutch of the present invention is The rotating shaft of 1 is formed in a double cylinder shape, and a coil spring is disposed (entered) in the hollow portion, so that the bearing portion and the coil spring are arranged in a direction (radial direction) perpendicular to the axial direction. It becomes possible to do. As a result, the electromagnetic spring clutch can be reduced in thickness and size.

  According to the third aspect, the sliding portion (bearing portion) between the first rotating shaft and the field core, and the winding portion between the coil spring and the first rotating shaft and the second rotating shaft are orthogonal to the axial direction. It is possible to more efficiently configure the arrangement that overlaps in the direction (radial direction) to be performed, and it is particularly suitable as a configuration for reducing the axial length.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view (upper half sectional view) showing an example of an electromagnetic spring clutch 1 according to an embodiment of the present invention. FIG. 2 is a front view of the electromagnetic spring clutch 1. FIG. 3 is an exploded perspective view showing an assembly structure of the first rotating shaft 2, the collar-like member 5 and the coil spring 7 of the electromagnetic spring clutch 1.

  The electromagnetic spring clutch 1 shown in FIG. 1 supports a ring-shaped field core 11 having a ring-shaped cross section, an electromagnetic coil 10 built in the field core 11, and the field core 11 so as to be rotatable. The first rotating shaft 2, the second rotating shaft 3 that is coaxial with the first rotating shaft 2 and supported rotatably on the first rotating shaft 2, and rotates on the second rotating shaft 3. A flange-shaped member 5 that is freely provided and extends in a flange shape in a direction facing the end surface 11 a of the field core 11, an input hub 4 provided on the second rotating shaft 3, and a field core 11 of the collar-shaped member 5. The armature 6 is provided on the surface to be mounted, and the coil spring 7 is engaged with the first rotating shaft 2 at one end and the collar member 5 at the other end. In the present application, the term is used as the “axial direction” as the direction parallel to the longitudinal direction of the first rotating shaft 2 and the “radial direction” as the direction orthogonal to the axial direction.

  As shown in FIG. 1, the field core 11 is formed in a ring shape with a cross section having a square shape. The electromagnetic coil 10 is built in this ring-shaped space. The electromagnetic coil 10 is configured by winding an electric wire around the outer peripheral surface of a coil bobbin, and is electrically connected to a power source via a terminal box 22. Specifically, the field core 11 includes a bottomed double ring portion having an opening on one end side and a yoke 11a that closes the opening.

  Reference numeral 2 shown in FIG. 1 denotes a first rotating shaft. The first rotating shaft 2 is formed using a synthetic resin material, and has an outer cylinder part 2a and an inner cylinder part 2c (FIG. 3), and the outer cylinder part 2a and the inner cylinder part 2c on one end side in the axial direction. Is formed in a double cylindrical shape having an opening on the other end side. The space between the outer cylinder part 2 a and the inner cylinder part 2 c is the hollow part 12. In the present embodiment, as shown in FIG. 1, the axial length of the inner cylindrical portion 2c is configured to be longer than the axial length of the outer cylindrical portion 2a, but each length is appropriately set. . The outer diameter of the outer cylindrical portion 2a of the first rotating shaft 2 is slightly smaller than the inner diameter of the field core inner peripheral portion 11b, and the outer cylindrical portion 2a is inserted into the field core inner peripheral portion 11b. As a result, the first rotating shaft 2 is rotatably supported by the field core 11.

  A groove 2j (FIG. 3) is formed on the outer peripheral surface of the end portion of the inner cylindrical portion 2c and the retaining ring 21 is fitted, and a snap fit engagement claw 2k is provided on the end portion of the outer cylindrical portion 2a. Thus, the end of the field core 11 is snap-fit engaged. The retaining ring 21 and the snap-fit engagement claw 2k restrict movement of each component of the electromagnetic spring clutch 1 in the axial direction.

  As shown in FIGS. 1 and 3, in the present embodiment, the inner cylindrical portion 2c of the first rotating shaft 2 includes a step portion 2f and is configured in a two-stage structure of a large diameter portion 2e and a small diameter portion 2d. The Here, the outer diameter of the large-diameter portion 2e is formed to be the same as the outer diameter of the second rotating shaft 3 (external cylindrical portion 3a described later). On the other hand, the outer diameter of the small diameter portion 2d is formed to be slightly smaller than the inner diameter of the second rotating shaft 3 (an inner cylindrical portion 3b described later). Part 3b). As a result, the second rotary shaft 3 is rotatably supported by the first rotary shaft 2. An insertion hole 2m is formed in the axial direction at the center of the inner cylindrical portion 2c of the first rotating shaft 2, and an output shaft (not shown) is inserted into the insertion hole 2m. The insertion hole 2m and the output shaft are formed in a D-shaped cross section (D-cut portion 2n), whereby the output shaft and the first rotation shaft 2 can be rotated together.

  1 shown in FIG. 1 is a second rotating shaft. The second rotating shaft 3 is formed using a synthetic resin material, and is provided with an input hub 4 that extends continuously in the radial direction integrally with the second rotating shaft 3. The second rotating shaft 3 and the input hub 4 may be formed integrally or separately. In the present embodiment, the second rotating shaft 3 is formed in a structure in which the outer cylindrical portion 3a is closely fitted to the inner cylindrical portion 3b, and the outer cylindrical portion 3a is a synthetic resin material that is resistant to sliding wear. It consists of.

  1 shown in FIG. 1 is a coil spring. The coil spring 7 is formed to have an outer diameter smaller than the inner diameter of the outer cylindrical portion 2 a of the first rotating shaft 2, and the outer diameter of the inner cylindrical portion 2 c of the first rotating shaft 2 and the second rotating shaft 3. The inner diameter is smaller than the outer diameter, and the inner cylinder 2c and the outer periphery of the second rotating shaft 3 are fitted over each other. In the present embodiment, the outer diameter of the inner cylindrical portion 2c and the outer diameter of the second rotating shaft 3 are formed substantially the same. Further, the coil spring 7 is arranged with one end side entering the hollow portion 12 between the outer cylinder portion 2a and the inner cylinder portion 2c. Here, both ends of the coil spring 7 are bent. Among them, the end portion 7 a bent in the axial direction is locked in the locking groove 2 p formed in the first rotating shaft 2, and the other end portion 7 b bent in the radial direction is formed in the collar-like member 5. The locking groove 5a is locked. In addition, the hollow part 12 is formed in the depth over the full length of the width | variety of the ring part of the field core 11. FIG.

  With this configuration, for example, in the conventional electromagnetic spring clutch 100 and the like, the bearing portion 122 and the coil spring 140 and the like are provided side by side in the axial direction, whereas the electromagnetic spring clutch 1 according to the present invention is configured as follows. One end side of the coil spring 7 can enter into the hollow portion 12 of the first rotating shaft 2 formed in a double cylindrical shape. That is, the sliding portion (bearing portion) between the first rotating shaft 2 and the field core 11 and the winding portion between the coil spring 7 and the first rotating shaft 2 and the second rotating shaft 3 are orthogonal to the axial direction. It is possible to configure as an arrangement that overlaps in the direction (radial direction). Thereby, compared with the conventional electromagnetic spring clutch 100, there exists an effect that significant thickness reduction can be achieved regarding an axial direction. Furthermore, it is possible to downsize the device to which the clutch is attached.

  The hollow portion 12 is formed to have a depth that extends over almost the entire length of the ring portion of the field core 11, so that the sliding portion (bearing portion) between the first rotating shaft and the field core, the coil spring, and the first In the electromagnetic spring clutch 1, it is possible to more efficiently configure an arrangement in which the winding portions of the rotation shaft and the second rotation shaft are overlapped in a direction (radial direction) orthogonal to the axial direction. Particularly, it is suitable as a configuration for reducing the axial length.

  1 is a collar-shaped member. The collar member 5 is provided on the second rotating shaft 3, that is, at a position surrounding the outer periphery of the second rotating shaft 3. In the present embodiment, both end portions of the collar member 5 in the axial direction are rotatably supported by the first rotating shaft 2 and the input hub 4. The collar member 5 has a shape extending in a rib shape in a direction facing the end face (yoke) 11a of the field core, and an armature 6 is fixed to the face of the collar member 5 facing the yoke 11a. The shaped member 5 and the armature 6 can rotate together. At this time, the armature 6 is located on the opposite side of the electromagnetic coil 10 with the yoke 11a interposed therebetween. The collar-like member 5 is formed in a cup shape having an outer wall portion extending in the axial direction at the outer edge portion thereof, so that dust such as toner, paper dust, grease, etc. is placed between the armature 6 and the yoke 11a. The effect of the cover which prevents entering can be produced, and it is suitable.

  The armature 6 is formed in a continuous or intermittent disk shape using a magnetic material. The outer diameter of the armature 6 is formed to be the same as or larger than the outer diameter of the field core 11.

  With this configuration, it is possible to increase the outer diameter of the armature 6 to the same extent as the outer diameter of the field core 11 as compared with the conventional electromagnetic spring clutch 100. In other words, the diameter of the contact surface with the field core 11 in the armature 6 can be made larger. This makes it possible to reduce the size of the electromagnetic coil 10 required to obtain the same friction torque. As a result, not only the electromagnetic spring clutch 1 can be reduced in size and weight, but also power consumption and manufacturing cost can be reduced. Further, in the conventional electromagnetic spring clutch 100 and the like, the armature is formed in a cylindrical shape, whereas in the electromagnetic spring clutch 1 according to the present invention, the armature 6 is formed in a plate shape, so that it is thin in the axial direction. It also contributes to

  Here, as shown in FIG. 1, the engagement protrusion 15 is provided to stand in the radial direction from the field core 11. The engagement protrusion 15 is fixed to an engagement portion (not shown) on the apparatus side where the electromagnetic spring clutch 1 is installed, and prevents the electromagnetic spring clutch 1 from being rotated around the output shaft or the like.

It continues and demonstrates operation | movement of the electromagnetic spring clutch 1 provided with the said structure.
When the electromagnetic coil 10 is in a non-energized state, the electromagnetic spring clutch 1 first transmits the rotational force input to the input hub 4 to the second rotary shaft 3. When the second rotating shaft 3 rotates in the direction to wind the coil spring 7, the coil spring 7 is wound and the first rotating shaft 2 and the second rotating shaft 3 are connected to each other. Therefore, both rotating shafts rotate together. As a result, an output shaft (not shown) inserted into the first rotating shaft 2 rotates. At this time, since the electromagnetic force does not act on the armature 6 fixed to the collar-shaped member 5 from the electromagnetic 10, the collar-shaped member 5 has the first rotating shaft 2 to which the coil spring 7 and the coil spring 7 are fitted. Together with the second rotary shaft 3, the second rotary shaft 3 is idled.

  In this state, when the electromagnetic coil 10 is energized, a magnetic circuit is formed in the field core 11 and the armature 6. As a result, the armature 6 receives the attractive force from the electromagnetic coil 10 and is attracted to the yoke 11a.

  When the armature 6 is attracted to the yoke 11a, the rotation of the armature 6 and the collar-like member 5 to which the armature 6 is fixed is braked, and the first rotating shaft 2 and the collar, which have been rotating integrally until then, are braked. A difference occurs in the number of rotations with the shaped member 5. The coil spring 7 is unwound and loosened by this difference in rotational speed, and the connection between the first rotary shaft 2 and the second rotary shaft 3 by the coil spring 7 is released. As a result, the rotational force input to the input hub 4 is transmitted to the second rotating shaft 3, but is not transmitted to the first rotating shaft 2, so that the rotation of the output shaft stops. At this time, the second rotating shaft 3 idles in the coil spring 7.

  When the electromagnetic coil 10 is de-energized again, the attractive force of the electromagnetic coil 10 with respect to the armature 6 is lost, so that the adsorption between the armature 6 and the yoke 11a is released. The collar-like member 5 starts to idle again, and the braking is released. Therefore, the rotational force input to the input hub 4 is transmitted to the second rotating shaft 3, and the second rotating shaft 3 rotates in the direction to wind the coil spring 7, so that the coil spring 7 is wound. Since the first rotating shaft 2 and the second rotating shaft 3 are connected to each other, both the shafts start to rotate together, and the rotational force is transmitted to the output shaft.

  By the operation described above, it is possible to transmit / not transmit the input to the input hub 4 to the output shaft by energizing / de-energizing the electromagnetic coil 10, and the electromagnetic spring clutch 1 can be used as a clutch mechanism. .

  As described above, the electromagnetic spring clutch according to the present invention has a plurality of effective configurations for reducing the thickness, and synergistically exhibits the effect of reducing the thickness, thereby comparing with the conventional electromagnetic spring clutch. Thus, a significant reduction in thickness is achieved. Furthermore, by making it possible to increase the friction torque on the armature friction surface, it is possible to reduce the size of the electromagnetic coil as compared with the conventional case.

  In this embodiment, the field core and the armature are attracted by energization of the electromagnetic coil, so that the coil spring is released from tightening, and the first rotating shaft and the second rotating shaft are released. The “normally closed electromagnetic spring clutch” in which the connection with the rotating shaft is released has been described as an example, but the technical idea according to the present invention is applied to the “normally open electromagnetic spring clutch” as shown in FIG. Of course you can.

It is a side view (upper half sectional view) showing an example of an electromagnetic spring clutch according to an embodiment of the present invention. It is a front view of the electromagnetic spring clutch shown in FIG. It is a disassembled perspective view which shows the assembly structure of the 1st rotating shaft, collar member, and coil spring of the electromagnetic spring clutch shown in FIG. It is the schematic which shows an example of the electromagnetic spring clutch which concerns on the conventional embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electromagnetic spring clutch 2 1st rotating shaft 2a Outer cylinder part of 1st rotating shaft 2b Connection part of 1st rotating shaft 2c Inner cylinder part of 1st rotating shaft 2d Of inner cylinder part of 1st rotating shaft Small diameter portion 2e Large diameter portion of the inner cylindrical portion of the first rotating shaft 2f Step portion of the inner cylindrical portion of the first rotating shaft 2h Flange portion of the first rotating shaft 2j Groove portion of the first rotating shaft 2k First Snap-fit engagement claw of rotating shaft 2m 1st rotating shaft insertion port 2n D-cut portion of 1st rotating shaft 2p Locking groove of 1st rotating shaft 3 2nd rotating shaft 2a 2nd rotating shaft External cylindrical part 2b Internal cylindrical part of the second rotating shaft 4 Input hub 5 Collar member 5a Collar member locking groove 6 Armature 7 Coil spring 10 Electromagnetic coil 11 Field core 11a End face of the field core (yoke)
11b Inner peripheral part of field core 12 Hollow part 15 Engaging protrusion 21 Retaining ring 22 Terminal box

Claims (3)

A ring-shaped field core in which a cross-section of the ring portion has a square shape;
A first rotating shaft inserted through the field core and rotatably supported;
A second rotating shaft coaxially supported by the first rotating shaft and rotatably supported on the first rotating shaft;
A collar-like member that is rotatably provided on the second rotation shaft and extends in a brim shape in a direction facing the end face of the field core;
An input hub provided on the second rotating shaft;
An armature provided on a surface of the collar-like member facing the field core;
A coil spring having one end on the first rotating shaft and the other end locked on the collar-shaped member;
When the electromagnetic coil is energized or de-energized, the field core and the armature are attracted or dissociated, whereby the coil spring is wound or released, and the first rotating shaft and the second rotating shaft are Is an electromagnetic spring clutch that is connected or released.
The first rotating shaft includes an outer cylinder part and an inner cylinder part, a connecting part for connecting the outer cylinder part and the inner cylinder part is provided on one end side, and a double part having an opening on the other end side. While being formed in a cylindrical shape, the outer cylinder portion is inserted through the field core and is supported by the field core, and the inner cylinder portion is rotatably inserted in the second rotation shaft,
One end side of the coil spring enters into a hollow portion between the outer cylinder portion and the inner cylinder portion. The coil spring is formed to have an outer diameter smaller than an inner diameter of the outer cylinder portion, and is formed to have an outer diameter smaller than an outer diameter of the inner cylinder portion and an outer diameter of the second rotating shaft. The electromagnetic spring clutch according to claim 1, wherein the electromagnetic spring clutch is fitted to an outer peripheral portion of the cylindrical portion and the second rotating shaft. 3. The electromagnetic spring clutch according to claim 1, wherein the hollow portion is formed to have a depth extending substantially over the entire length of the ring portion of the field core.

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