JP2016050595A - Centrifugal clutch and geared motor with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal clutch capable of transmitting a larger driving force and in turn protecting an input side member when a strong force from an output side against a rotation is applied.SOLUTION: A centrifugal clutch 200 comprises a clutch drum 40 having a cylindrical side wall part 43 and rotating around a center axis A of the side wall part 43; and a clutch shoe 30 rotated around the center axis A and moved to be contacted with an inner circumferential surface of the side wall part 43 by centrifugal force under the rotation. The inner circumferential surface of the side wall part 43 has a shape with a recessed holding part 45 protruded from inside toward outside of a circle C with the center axis A being applied as a center and the clutch shoe 30 is fitted to the recessed holding part 45 in such a way that a contact plane between the clutch shoe 30 and the clutch drum 40 for applying a pressing force from the clutch shoe 30 against the clutch drum 40 may be inclined in respect to a circumferential direction of the circle C with the center axis A being applied as a center.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a centrifugal clutch and a geared motor, and is suitable for transmitting a large torque.

  Examples of the shutter and door include an electric shutter and an automatic door that are opened and closed by the power of a motor. For such shutters and doors, a geared motor is generally used that transmits a larger torque by decelerating and transmitting the rotation of the motor. There is a demand for such an electric shutter or automatic door to be opened and closed by human power in an emergency. However, when the motor and the shutter, the door, and the like are connected via a mechanism such as a gear, a force for opening and closing the shutter, the door, etc. by human power is transmitted to the motor. In order to rotate the motor in a stationary state, it is necessary to rotate the motor against the torque of the motor. In this case, the shutter, the door, and the like must be opened and closed against the torque. Therefore, when the motor rotates, the power of the motor is transmitted to the shutter, door, etc. When the motor does not rotate, the power of the motor and the shutter, door, etc. does not transmit to the motor. It is preferred that the transmission is cut off. A centrifugal clutch may be used to perform such power transmission / disconnection.

  Patent Document 1 listed below describes an example of a centrifugal clutch. This centrifugal clutch includes a pair of fan-shaped clutch shoes and a cylindrical clutch drum surrounding the pair of clutch shoes. The pair of clutch shoes are disposed on the shaft target with the arcuate surfaces facing the outer peripheral side.

  When the pair of clutch shoes rotate about the shaft center, the respective clutch shoes move to the outer peripheral side by centrifugal force, and the arcuate surface of each clutch shoe and the inner peripheral surface of the clutch drum come into contact with each other. The rotational force of the clutch shoe is transmitted to the clutch drum by the frictional force of each of the contacted surfaces. Therefore, when the motor is mounted so that the pair of clutch shoes rotate as described above, the motor power can be transmitted to the clutch drum by the rotation of the motor. On the other hand, when the pair of clutch shoes are not rotating, each clutch shoe is separated from the clutch drum, so that the power from the clutch drum is not transmitted to the clutch shoe.

JP 2011-85184 A

  Incidentally, there is a need to transmit a larger force from the motor in a state where the motor is attached to the centrifugal clutch described in Patent Document 1 so that the power of the motor is transmitted. Accordingly, there is a need for a centrifugal clutch that can transmit a larger torque from a power input side member to an output side member.

  On the other hand, if the motor power input side member and output side member are completely fixed when the motor rotates, the motor and gears will be destroyed if the power output side member does not move for some reason. There is a concern that it will.

  Therefore, the present invention provides a centrifugal clutch and a geared motor that can protect a member on the input side when a strong force against rotation is applied from the output side while being able to transmit larger power. It is something to try.

  The centrifugal clutch of the present invention has a cylindrical side wall portion, and rotates around the central axis of the side wall portion, and rotates around the central axis, and the inner periphery of the side wall portion due to the centrifugal force generated by the rotation. A clutch shoe that moves so as to contact the surface, and the inner peripheral surface of the side wall portion has a concave holding portion that protrudes from the inside of a circle centered on the central axis to fit the clutch shoe. The contact surface between the clutch shoe and the clutch drum that applies a pressing force from the clutch shoe to the clutch drum in a state where the clutch shoe is fitted to the holding portion is a circle centered on the central axis. It is characterized by being inclined with respect to the circumferential direction.

  Further, the geared motor of the present invention includes a centrifugal clutch, a motor having a motor shaft that rotates together with the clutch shoe, a connection shaft that rotates together with the clutch drum, and a rotation that is less than the number of rotations of the connection shaft. And a speed reducer having an output shaft that rotates at the same time.

  In such a centrifugal clutch and a geared motor, the clutch shoe is fitted to the holding portion when the clutch shoe contacts the inner peripheral surface by centrifugal force. Therefore, in addition to the frictional force between the clutch shoe and the clutch drum, power is transmitted from the clutch shoe to the clutch drum by a pressing force along the rotational direction applied from the clutch shoe to the clutch drum. On the other hand, in the centrifugal clutch described in Patent Document 1 in which the inner peripheral surface of the clutch drum is circular, power is transmitted only by the frictional force between the clutch shoe and the clutch drum. Therefore, according to the centrifugal clutch of the present invention, larger power can be transmitted.

  Further, in a state where the clutch shoe is fitted to the holding portion of the clutch drum, the contact surface between the clutch shoe and the clutch drum that applies the above pressing force from the clutch shoe to the clutch drum is a circumferential direction of a circle centering on the central axis. It is assumed to be slanted. The clutch shoe receives a resistance against the above pressing force from the clutch drum. The pressing force is a direction in contact with the circle, and the drag force is a force opposite to the pressing force. This drag force can be decomposed into a direction in which the clutch shoe comes out of the holding portion and a direction in which the clutch shoe and the holding portion are in contact with each other. For this reason, in a state where power is transmitted from the clutch shoe to the clutch drum, a force is applied to the clutch drum against the power, and when this force is larger than a predetermined magnitude, the clutch shoe receives from the clutch drum. You can get out of the holding part by drag. Therefore, when a strong force against rotation is applied from the output side, the input side member can be protected.

It is a figure which shows the geared motor using the centrifugal clutch which concerns on 1st Embodiment of this invention. It is sectional drawing in the plane direction of a centrifugal clutch. It is a figure which shows the locked state of a centrifugal clutch from the same viewpoint as FIG. It is a figure which shows the centrifugal clutch of 2nd Embodiment of this invention from the same viewpoint as FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a centrifugal clutch and a geared motor using the centrifugal clutch according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
It is a figure showing geared motor 1 using a centrifugal clutch concerning a 1st embodiment of the present invention. As shown in FIG. 1, the geared motor 1 of the present embodiment includes a motor 100, a centrifugal clutch 200, and a speed reducer 300. In FIG. 1, the centrifugal clutch 200 is shown in a cross-sectional view along the central axis A of the centrifugal clutch 200.

  FIG. 2 is a cross-sectional view of the centrifugal clutch 200 in a planar direction (a direction perpendicular to the central axis A). Specifically, it is a view of the speed reducer 300 side from a plane passing through the line VV in FIG. As shown in FIGS. 1 and 2, the centrifugal clutch 200 includes a housing 10, a bracket 20, a clutch shoe 30, and a clutch drum 40 as main components. 1 and 2, the clutch shoe 30 is not shown in cross section for easy understanding.

  The housing 10 has a cylindrical part 11 and a bottom plate part 12 as main components. The cylinder part 11 has a substantially cylindrical shape. The bottom plate portion 12 is disposed so as to close one opening of the tube portion 11 and is connected to an edge on one side of the tube portion 11. A plurality of screw holes 13 are formed at positions away from the center of the bottom plate portion 12, and screws (not shown) are screwed into the screw holes 13, so that the housing 10 and the housing of the speed reducer 300 are connected. They are fixed to each other. Thus, the centrifugal clutch 200 and the speed reducer 300 are fixed to each other. In FIG. 1, only one screw hole 13 is shown. An opening centered on the central axis A is formed at the center of the bottom plate portion 12, and a metal bush 14 is press-fitted into the opening of the bottom plate portion 12. Accordingly, the metal bush 14 is fixed to the bottom plate portion 12. A through hole is formed in the center of the metal bush 14, and a connecting shaft 310 of the speed reducer is inserted into the centrifugal clutch 200 from this through hole. The metal bush 14 serves as a bearing for the connection shaft 310. The connection shaft 310 rotates about the central axis A.

  The side opposite to the bottom plate 12 side of the housing 10 is opened, and an inner cap 15 is fitted into the inside of the cylindrical portion 11 from this opening. An opening is formed in the center of the inner cap 15. In addition, an outer cap 16 is fitted into the edge forming the opening of the cylindrical portion 11. The outer cap 16 is fixed to the cylindrical portion 11 by being press-fitted into the cylindrical portion 11. A plurality of screw holes are formed in the outer cap 16, and the outer cap 16 and the motor 100 are fixed by screwing screws 17 into the screw holes. Thus, the centrifugal clutch 200 and the motor 100 are fixed to each other. An opening is formed in the center of the outer cap 16. The motor shaft 110 of the motor 100 is inserted into the centrifugal clutch 200 from the opening of the outer cap 16 and the opening of the inner cap 15, and the tip of the motor shaft 110 is spaced from the tip of the connection shaft 310 of the speed reducer 300 by a predetermined distance. Open and face each other. The motor shaft 110 rotates about the central axis A and transmits the power of the motor 100 to the centrifugal clutch 200.

  An input joint 29 is fixed to the motor shaft 110. The input joint 29 is a cylindrical member, and the motor shaft 110 is press-fitted into the through hole of the input joint 29.

  A bracket 20 is fixed to the input joint 29. Therefore, the bracket 20 is fixed to the motor shaft 110 via the input joint 29. As shown in FIGS. 1 and 2, the bracket 20 mainly includes a bracket fixing portion 21 fixed to the input joint 29 and four side branch portions 22 extending from the bracket fixing portion 21 in a direction perpendicular to the central axis A. It has as a new configuration. The bracket fixing portion 21 has a through hole at the center, and the input joint 29 is press-fitted into the through hole. In the present embodiment, as shown in FIG. 1, the bracket fixing portion 21, the input joint 29, and the motor shaft 110 are arranged so that the end portions of the bracket fixing portion 21, the input joint 29, and the motor shaft 110 are substantially flush with each other. And are fixed.

  As shown in FIG. 2, the four side branch portions 22 of the bracket 20 extend in a cross shape. Each side branch portion 22 is formed with a support hole 22 </ b> H from the tip toward the bracket fixing portion 21 along the longitudinal direction of the side branch portion 22. As shown in FIG. 1, each support hole 22 </ b> H is formed so that its central axis does not overlap the bracket fixing portion 21. Further, the air holes 21H are formed so as to extend from the deepest part which is a dead end of each support hole 22H. The vent hole 21H communicates with the space between the motor shaft 110 and the connection shaft 310. Therefore, the air in the support hole 22H can go to and from the space between the motor shaft 110 and the connection shaft 310 through the vent hole 21H.

  A clutch shoe 30 is attached to each side branch portion 22 so as to be movable in a direction perpendicular to the central axis A. The clutch shoe 30 has a rod part 31 and a head part 32 fixed to one end of the rod part 31 as main components. The rod portion 31 is a cylindrical member having a diameter slightly smaller than that of the support hole 22H, and is inserted into each support hole 22H formed in the side branch portion 22. For this reason, the rod part 31 can move along the longitudinal direction of the support hole 22H extending perpendicularly to the central axis A, whereby the clutch shoe 30 can move in the direction perpendicular to the central axis A as described above. It is said. The head portion 32 has a cylindrical shape thicker than the rod portion 31 on the rod portion 31 side, and a hemispherical shape on the opposite side to the rod portion 31 side.

  The input joint 29, the bracket 20 and the clutch shoe 30 configured as described above constitute members on the power input side of the motor 100, and these members rotate with the motor shaft 110 about the central axis A.

  Next, members on the power output side of the motor 100 in the centrifugal clutch 200 will be described. The output side member of the centrifugal clutch 200 includes an output joint 49 and a clutch drum 40.

  As described above, the output joint 49 is fixed to the connection shaft 310 of the speed reducer 300 inserted into the centrifugal clutch 200 through the through hole of the metal bush 14. The output joint 49 is a cylindrical member, and the connection shaft 310 is press-fitted into the through hole of the output joint 49.

  A clutch drum 40 is fixed to the output joint 49. Therefore, the clutch drum 40 is fixed to the connection shaft 310 via the output joint 49. The clutch drum 40 has a clutch drum fixing part 41, a flat plate part 42, and a side wall part 43 as main components. The clutch drum fixing portion 41 has a through hole at the center, and an output joint 49 is press-fitted into the through hole. In the present embodiment, as shown in FIG. 1, the clutch drum fixing portion 41 and the output joint 49 are connected so that the end portions of the clutch drum fixing portion 41, the output joint 49, and the connection shaft 310 are substantially flush. The shaft 310 is fixed. A slight gap is formed between the clutch drum fixing portion 41 and the bracket fixing portion 21, and the clutch drum 40 and the bracket 20 can freely rotate with each other.

  A flat plate portion 42 that extends in a direction perpendicular to the central axis A is connected to the clutch drum fixing portion 41. The flat plate portion 42 is a member having a circular outer periphery, and extends from the clutch drum fixing portion 41 to the front of the inner peripheral surface of the cylindrical portion 11 of the housing 10. A side wall portion 43 is connected to the outer periphery of the flat plate portion 42. The side wall portion 43 has a cylindrical shape extending along the direction of the central axis A. A slight gap is formed between the outer peripheral surface of the side wall portion 43 and the inner peripheral surface of the cylindrical portion 11 of the housing 10. Further, as shown in FIG. 2, the inner peripheral surface of the side wall portion 43 has an uneven shape, and a convex portion 44 located inside a circle C indicated by a broken line centering on the central axis A, and the circle C And a concave holding portion 45 protruding outward from the inside. When viewed along the central axis A, the holding portion 45 has an arc shape, and the radius of curvature substantially matches the curvature of the hemispherical tip of the head portion 32 of the clutch shoe 30. Further, the number of the holding portions 45 is preferably a multiple of the number of the clutch shoes 30. In this case, when the clutch shoe 30 is fitted to the holding portion 45 as described later, all the clutch shoes 30 can be fitted simultaneously.

  The output joint 49 and the clutch drum 40 which are members on the output side having the above-described configuration rotate together with the connection shaft 310 about the central axis A.

  Although not particularly shown, the connection shaft 310 and the output shaft 320 are connected by a mechanism in the speed reducer 300, and the output shaft 320 rotates at a smaller number of rotations than the number of rotations of the connection shaft 310.

  Next, normal operation of the geared motor 1 using the centrifugal clutch 200 will be described.

  First, electric power is applied to the motor 100 from a power source (not shown), and the motor shaft 110 rotates about the central axis A. As described above, the motor shaft 110 and the bracket 20 are fixed to each other via the input joint 29, and the clutch shoe 30 is inserted into the support hole 22H of the bracket 20. Accordingly, the bracket 20 rotates about the central axis A together with the clutch shoe 30 as the motor shaft 110 rotates.

  The clutch shoe 30 moves toward the side wall 43 of the clutch drum 40 by the centrifugal force due to this rotation. At this time, since air enters the support hole 22H through the vent hole 21H, the clutch shoe 30 can move appropriately. Then, the tip end portion of the head portion 32 of the clutch shoe 30 is fitted to the holding portion 45 on the inner peripheral surface of the side wall portion 43. Thus, the centrifugal clutch 200 is locked. FIG. 3 is a diagram showing the locked state of the centrifugal clutch 200 from the same viewpoint as FIG. When the clutch shoe 30 rotates in the direction indicated by the arrow in FIG. 3 in the locked state, the clutch shoe 30 presses the clutch drum 40 around the area S1 indicated by the dotted line in FIG. That is, in the centrifugal clutch 200, when the contact surface between the clutch shoe 30 and the clutch drum 40 that applies the pressing force from the clutch shoe 30 to the clutch drum 40 is viewed along the central axis A, a circle centering on the central axis A is used. It is oblique to the circumferential direction of C. Being oblique with respect to the circumferential direction means being oblique with respect to the tangent of the circle C on the tangent surface. In the present embodiment, when viewed along the central axis A, the holding portion 45 has an arc shape, and a portion of the head portion 32 of the clutch shoe 30 that fits the holding portion 45 has an arc-shaped convex shape. Thus, the contact surface is inclined with respect to the circumferential direction of the circle C. In the centrifugal clutch 200 thus locked, the clutch shoe 30 and the clutch drum 40 are fixed to each other, so that the clutch drum 40 rotates together with the clutch shoe 30 that rotates together with the motor shaft 110.

  As described above, the clutch drum 40 and the connection shaft 310 of the speed reducer 300 are fixed to each other via the output joint 49. Accordingly, the connection shaft 310 rotates about the central axis A by the rotation of the clutch drum 40. As the connection shaft 310 rotates, the output shaft 320 rotates at a speed lower than that of the connection shaft 310.

  In this way, the power of the motor 100 is transmitted to the output shaft 320.

  On the other hand, when no power is applied to the motor 100 and the motor shaft 110 is not rotating, the clutch shoe 30 does not move toward the side wall 43 of the clutch drum 40, and therefore the clutch shoe 30 and the clutch drum 40 are not fixed to each other. . In this state, even if some force is applied to the output shaft 320 and the output shaft 320 rotates and the connection shaft 310 rotates by this rotation, the clutch drum 40 rotates but the clutch shoe 30 does not rotate. Accordingly, the force applied to the output shaft 320 is disconnected in the centrifugal clutch 200 and is not transmitted to the motor 100.

  As described above, when the motor 100 is operating normally, when the electric power applied to the motor 100 is cut off and the motor shaft 110 is stopped from rotating, the clutch shoe 30 stops rotating. The clutch shoe 30 is positioned on the side of the side wall 43 of the clutch drum 40 and remains fitted to the holding portion 45, and is in the same state as shown in FIG. However, in this state, centrifugal force is not acting on the clutch shoe 30. In this state, the output shaft 320 may be rotated by some force, the connection shaft 310 may be rotated by the rotation, and the clutch drum 40 may be rotated. For example, the clutch drum 40 may rotate in the direction of the arrow shown in FIG. In this case, the clutch drum 40 presses the clutch shoe 30 around the area S2 indicated by the dotted line in FIG.

  As shown in FIG. 3, the contact surface between the clutch shoe 30 and the clutch drum 40 in the region S <b> 2 is in the circumferential direction of the circle C in a state where the clutch shoe 30 is fitted to the holding portion 45 of the clutch drum 40. On the other hand, it is slanted. The pressing force applied to the clutch shoe 30 by the clutch drum 40 is a direction in contact with the circle C, and the pressing force received by the clutch shoe 30 from the clutch drum is a direction in which the clutch shoe 30 comes out of the holding portion 45 (clutch shoe 30 Can be disassembled into a direction of moving toward the central axis A) and a direction of contact with the clutch shoe 30 (a direction in which the holding portion 45 contacts in the region S2). For this reason, the clutch shoe 30 can come out of the holding portion 45 by the pressing force received from the clutch drum 40. Accordingly, the clutch shoe 30 comes out of the holding portion 45 and the clutch drum 40 rotates idly with respect to the clutch shoe 30. As described above, the clutch shoe 30 and the clutch drum 40 that apply a pressing force from the clutch drum 40 to the clutch shoe 30 so that the clutch drum 40 rotates the clutch shoe 30 in a state where the clutch shoe 30 is fitted to the holding portion 45. Even if the clutch shoe 30 is not biased toward the central axis A side, the contact surface (contact surface in the region S2) is inclined with respect to the circumferential direction of the circle C centered on the central axis A. The clutch shoe 30 can come out of the holding portion 45.

  As described above, in the centrifugal clutch 200 of the present embodiment, since the clutch shoe 30 is fitted to the holding portion 45 as described above, in addition to the frictional force between the clutch shoe 30 and the clutch drum 40, the clutch shoe 30 Power is transmitted from the clutch shoe 30 to the clutch drum 40 by the pressing force along the rotational direction applied from 30 to the clutch drum 40. Therefore, compared with the case where the inner peripheral surface of the clutch drum is circular and the power is transmitted only by the frictional force, the centrifugal clutch 200 of this embodiment can transmit a larger power.

  Next, the non-normal operation of the geared motor 1 will be described.

  In a state where power from the motor 100 is transmitted to the output shaft 320, a strong force that resists rotation may be applied to the output shaft 320. For example, when the geared motor 1 is used for an automatic door, the automatic door is opened by the rotation of the motor 100, but a load or the like is caught on the automatic door and the automatic door cannot be opened. At this time, a strong force against rotation is applied to the output shaft 320 from the automatic door whose movement is restricted. When the clutch shoe 30 presses the clutch drum 40 in order for the clutch shoe 30 to rotate the clutch drum 40, the clutch shoe 30 receives a resistance against the pressing force from the clutch drum 40. This resistance tends to increase when a strong force against the rotation is applied to the output shaft 320 as described above.

  By the way, in a state where the clutch shoe 30 is fitted to the holding portion 45 of the clutch drum 40, the contact surface between the clutch shoe 30 and the clutch drum 40 in the region S1 is in the circumferential direction of the circle C as described above. And slanted. The pressing force applied to the clutch drum 40 by the clutch shoe 30 is a direction in contact with the circle C, and the drag force received by the clutch shoe 30 from the clutch drum is a force opposite to the pressing force. The drag force includes a direction in which the clutch shoe 30 comes out of the holding portion 45 (a direction in which the clutch shoe 30 moves toward the central axis A) and a direction in contact with the clutch shoe 30 (in the region S1, the holding in the clutch shoe 30). In the direction of contact with the portion 45). For this reason, when the drag is larger than a predetermined magnitude, the clutch shoe 30 can come out of the holding portion 45 by the drag received from the clutch drum 40. In this way, the clutch shoe 30 and the clutch drum 40 that apply a pressing force from the clutch shoe 30 to the clutch drum 40 so that the clutch shoe 30 rotates the clutch drum 40 in a state where the clutch shoe 30 is fitted to the holding portion 45. The contact surface (contact surface in the region S1) is inclined with respect to the circumferential direction of the circle C centered on the central axis A, so that the clutch shoe 30 can come out of the holding portion 45. Therefore, according to the centrifugal clutch 200 of this embodiment, when a strong force against rotation is applied from the output side of the output shaft 320 or the like, the input side member such as the motor 100 can be protected.

  Thereafter, the clutch shoe 30 rotates idly with respect to the clutch drum 40. If at least one of the head part 32 of the clutch shoe 30 and the side wall part 43 of the clutch drum 40 is made of resin, the sound that the head part 32 collides with the convex part 44 on the inner peripheral surface of the side wall part 43 when idling. Can be reduced. On the other hand, if both the head part 32 and the side wall part 43 are made of metal, it is easy to detect an abnormality due to the sound of the head part 32 hitting the convex part 44 when idling.

  Further, in the centrifugal clutch 200 of the present embodiment, the holding portion 45 has an arc shape, or a portion that fits the holding portion 45 of the clutch shoe 30 has an arc-shaped convex shape. Therefore, when the tip of the clutch shoe 30 is pulled out from the holding portion 45, the force in the direction in which the clutch shoe 30 received by the clutch shoe 30 from the side wall portion 43 of the clutch drum 40 is gradually weakened. Therefore, the motor shaft 110 that rotates idly can be smoothly moved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described in detail with reference to FIG. In addition, about the component which is the same as that of 1st Embodiment, or equivalent, except the case where it demonstrates especially, the same referential mark is attached | subjected and the overlapping description is abbreviate | omitted.

  FIG. 4 is a view showing the centrifugal clutch according to the second embodiment of the present invention from the same viewpoint as FIG. As shown in FIG. 4, the centrifugal clutch 201 of the present embodiment is different from the centrifugal clutch 200 of the first embodiment in that the inner peripheral surface of the side wall 43 of the clutch drum 40 is polygonal. In this embodiment, the case where the inner peripheral surface of the side wall part 43 is a regular octagon centering on the central axis A is shown. Moreover, in this embodiment, the vertex of the polygon is chamfered into a rounded shape. This chamfered apex portion is the holding portion 45 of this embodiment.

  According to the centrifugal clutch of the present embodiment, the holding portions 45 adjacent to each other are connected to each other in a plane, so that when the clutch shoe 30 rotates idly with respect to the clutch drum 40, the head portion 32 is attached to the side wall portion 43. Sound that hits the inner peripheral surface can be reduced.

  In the present embodiment, the case where the inner peripheral surface of the side wall portion 43 is a regular octagon is shown, but this is an example, and may be a regular dodecagon, for example. When the inner peripheral surface is a regular polygon as in the present embodiment, a polygon having a vertex that is a multiple of the clutch shoe 30 is preferable because all the clutch shoes 30 are fitted simultaneously. Moreover, in this embodiment, although the vertex of the polygon is chamfered in the rounded shape, it does not need to be chamfered.

  The present invention has been described above by taking the first and second embodiments as examples, but the present invention is not limited to these.

  For example, the number of side branch portions 22 may be other than four. However, it is preferable from the viewpoint of improving the rotation balance that the number of the side branch portions 22 is plural and extends around the central axis A at equal intervals.

  Further, the tip of the head portion 32 of the clutch shoe 30 may have a shape other than a hemispherical shape. For example, the tip of the head part 32 may be conical. In this case, it is preferable that the shape of the holding portion 45 is also conical.

  Further, although not particularly mentioned in the above embodiment, the clutch shoe 30 is made of a spring member or the like on the central axis side with a weak force as long as the clutch shoe 30 can be fitted to the holding portion 45 by centrifugal force when the clutch shoe 30 rotates. It may be energized.

  The centrifugal clutch 200 of the present embodiment is used with the motor 100 and the speed reducer 300 connected thereto, but the power input side member and the power output side member are connected to the centrifugal clutch 200. Any method may be used.

  As described above, the centrifugal clutch of the present invention can be used in various fields such as electric shutters, automatic doors, and other fields that transmit power from the input side and try to block power from the output side. it can.

DESCRIPTION OF SYMBOLS 10 ... Case 20 ... Bracket 22 ... Side branch part 22H ... Support hole 30 ... Clutch shoe 31 ... Rod part 32 ... Head part 40 ... Clutch drum 43 ... -Side wall part 45 ... Holding part 100 ... Motor 110 ... Motor shaft 200, 201 ... Centrifugal clutch 300 ... Reduction gear 310 ... Connection shaft 320 ... Output shaft

Claims (7)

A clutch drum having a cylindrical side wall and rotating around a central axis of the side wall;
A clutch shoe that rotates around the central axis and moves so as to contact the inner peripheral surface of the side wall portion by centrifugal force due to the rotation;
With
The inner peripheral surface of the side wall portion protrudes outward from the inside of a circle centered on the central axis, and has a concave holding portion into which the clutch shoe is fitted,
In a state where the clutch shoe is fitted to the holding portion, a contact surface between the clutch shoe and the clutch drum that applies a pressing force from the clutch shoe to the clutch drum is a circumferential direction around the central axis. Centrifugal clutch characterized by being inclined with respect to In a state where the clutch shoe is fitted to the holding portion, a contact surface between the clutch shoe and the clutch drum that applies a pressing force from the clutch drum to the clutch shoe is a circumferential direction of a circle centering on the central axis The centrifugal clutch according to claim 1, wherein the centrifugal clutch is inclined. The centrifugal clutch according to claim 2, wherein the holding portion has an arc shape. The centrifugal clutch according to claim 2, wherein the inner peripheral surface has a polygonal shape, and the holding portion is an apex portion of the polygon. The centrifugal clutch according to claim 4, wherein the apex portion is chamfered in an arc shape. The centrifugal clutch according to claim 3 or 5, wherein a portion of the clutch shoe that fits into the holding portion has an arcuate convex shape. The centrifugal clutch according to any one of claims 1 to 6,
A motor having a motor shaft that rotates with the clutch shoe;
A reduction shaft having a connection shaft that rotates together with the clutch drum, and an output shaft that rotates at a rotation less than the number of rotations of the connection shaft;
A geared motor comprising:

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