JP2008157422A - Driving force transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving force transmission device capable of effectively suppressing an operation failure or degradation of responsiveness. <P>SOLUTION: Protrusions 32 of quadrangular pyramid shape are erected in three rotation symmetric positions around an axis of an armature 30. A radial slant face 32a of each protrusion 32 is formed of an acutely inclined face to an anti-facing surface 31 so as to approach a second cam toward the radial outside of the armature 30. A circumferential slant face 32b of each protrusion 32 is formed of an acutely inclined face to the anti-facing surface 31 so as to approach the second cam in the circumferential direction of the armature 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a driving force transmission device.

Conventionally, a driving force transmission device described in Patent Document 1 is known. The driving force transmission device includes a cylindrical first rotating body that rotates in response to an input of a driving force, a shaft-shaped second rotating body that is coaxially disposed in a cylinder of the first rotating body, A clutch mechanism is provided between the first rotating body and the second rotating body and connects the two rotating bodies so that torque can be transmitted. The clutch mechanism is actuated by being pressed in the axial direction to connect the first rotating body and the second rotating body so as to transmit torque, and a pilot clutch juxtaposed in the axial direction of the main clutch, A cam mechanism that presses the main clutch in the axial direction by the operation of the pilot clutch. Further, an electromagnetic clutch that frictionally engages each clutch plate by a pressing force of an armature that is attracted by an electromagnet and moves in the axial direction is used as the pilot clutch. Then, the torque based on the rotation difference between the first rotating body and the second rotating body transmitted by the operation of the pilot clutch is converted into an axial pressing force by the cam mechanism to press the main clutch, and the first clutch A driving force is transmitted from the rotating body to the second rotating body.
JP 2002-61677 A

  In the driving force transmission device configured as described above, the cam member that presses the main clutch in the axial direction is made of an iron material in order to ensure its strength. For this reason, when the pilot clutch is not operating, that is, when the armature approaches the cam member when the armature can move freely in the axial direction, magnetic flux leaks from the armature to the cam member when the pilot clutch is operated, resulting in malfunction. May occur. Further, if the armature is close to the cam member side, when a relatively small current flows through the electromagnet according to the traveling state of the vehicle, the armature cannot be sufficiently attracted, and the responsiveness may be lowered. Therefore, in the driving force transmission device described in Patent Document 1, the surface of the armature facing the cam member is covered with a nonmagnetic member such as stainless steel. However, in order to cover one side of the armature with the non-magnetic member, a corresponding cost is required, so there is still room for improvement.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a driving force transmission device that can effectively suppress a malfunction or a decrease in responsiveness.

  In order to achieve the above object, the invention described in claim 1 includes a cylindrical first rotating body that is rotated by an input of a driving force, and an axial second shaft that is coaxially disposed rotatably in the first rotating body. A first clutch that is arranged between the rotating body and the first rotating body and the second rotating body and is connected to the first rotating body and the second rotating body so as to transmit torque by being pressed in the axial direction; A second clutch juxtaposed in the axial direction of the first clutch; the first rotating body provided between the first clutch and the second clutch; and transmitted through the second clutch, and the second clutch. A cam mechanism that presses the first clutch by converting a torque based on a rotational difference with the rotating body into an axial pressing force and moving the cam member in the axial direction; and a predetermined filling rate for the first rotating body And the second clutch is driven. And a plurality of clutch plates alternately arranged in the axial direction and axially movable at positions where the clutch plates are sandwiched between the electromagnets and juxtaposed in the axial direction of the cam member. And an annular armature provided so as to be rotatable integrally with a single rotating body, and configured as an electromagnetic clutch that frictionally engages each clutch plate by the pressing force of the armature that is attracted and moved by the electromagnet. A driving force transmission device, wherein a surface of the armature opposite to the clutch plate has a radially inclined surface inclined so as to approach the cam member side toward a radially outer side of the armature, and the armature At least one of the circumferential slopes inclined so as to approach the cam member side in the circumferential direction. It is the gist of.

  According to the above configuration, the armature can be separated from the cam member by the flow of the lubricating oil accompanying the rotation of the first rotating body when the pilot clutch is not operated. That is, when the radial slope is provided, the lubricating oil flows radially outward due to the centrifugal force when the first rotating body rotates at a high speed. Therefore, the radial slope is generated in the armature due to the flow of the lubricating oil. A force in a direction perpendicular to is applied. Since the radial slope is inclined so as to approach the cam member side, a force biased toward the second clutch is applied to the armature, and the armature moves toward the second clutch. On the other hand, when the circumferentially inclined surface is provided, when the first rotating body rotates at a relatively low speed, the lubricating oil is unevenly distributed under the first rotating body due to gravity, so that the lubricating oil is distributed in the circumferential direction of the armature. It will flow. Therefore, the armature moves to the second clutch side based on the same principle as described above. As described above, the gap between the armature and the electromagnet does not increase, and the electromagnet easily attracts the armature, so that the malfunction or the responsiveness is effectively suppressed.

  According to a second aspect of the present invention, in the driving force transmission device according to the first aspect, at least one of the radial slope and the circumferential slope is erected on the opposite surface. The gist is that the protrusion is formed.

According to the above configuration, since the radial slope and the circumferential slope are formed by the protrusion, it is possible to reliably generate the biasing force toward the second clutch due to the flow of the lubricating oil.
According to a third aspect of the present invention, in the driving force transmission device according to the second aspect, the projecting portion having the same shape has a rotationally symmetric position about the axis of the armature on the opposite surface. The gist is that it was formed.

According to the said structure, the urging | biasing force which generate | occur | produces in each protrusion equilibrates, and the movement to the 2nd clutch side is performed smoothly, without rattling.
According to a fourth aspect of the present invention, in the driving force transmission device according to the first aspect, the radial slope reduces the armature, and the thickness of the armature decreases from the radially outer side toward the radially inner side. The gist is that it is formed by forming a tapered shape.

  According to the above configuration, since the radial slope is formed by tapering the armature, the urging force toward the second clutch side can be generated without increasing the thickness of the armature, and the shaft of the driving force transmission device can be generated. The direction length can be shortened.

  According to the present invention, it is possible to provide a driving force transmission device capable of effectively suppressing a decrease in responsiveness without causing an armature malfunction.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, the driving force transmission device 1 includes a front housing 2 as a first rotating body formed in a bottomed cylindrical shape, and a hollow shaft shape that is freely rotatable in a cylinder of the front housing 2. And an inner shaft 3 as a second rotating body arranged coaxially.

  A shaft-like connecting portion 4 having a spline on the outer periphery protrudes from the bottom 2 a of the front housing 2, and the front housing 2 is connected to the propeller shaft 5 at the connecting portion 4. The front housing 2 rotates based on the driving force input from the propeller shaft 5.

  An annular rear housing 6 is screwed to the opening end 2 b of the front housing 2, and the inner shaft 3 includes a slide bearing 7 provided in a central hole 6 a of the rear housing 6 and a cylinder of the front housing 2. It is rotatably supported by a ball bearing 8 provided inside. A connecting portion (spline fitting portion) 9 (not shown) with a rear differential (not shown) is formed on the inner periphery of the shaft end (right side in the drawing) of the inner shaft 3 that is supported by the slide bearing 7. Has been.

  Further, in the cylinder of the front housing 2, a main clutch 10 capable of connecting the front housing 2 and the inner shaft 3 so as to transmit torque, and a pilot clutch juxtaposed in the axial direction of the main clutch 10 on the rear housing 6 side. 11 and a cam mechanism 12 interposed between the main clutch 10 and the pilot clutch 11 are provided.

  The main clutch 10 as the first clutch employs a multi-plate friction clutch in which a plurality of outer clutch plates 13 and inner clutch plates 14 provided so as to be movable in the axial direction are alternately arranged. Lubricating oil is accommodated in a space partitioned by the rear housing 6 and the inner shaft 3 in the front housing 2, and the main clutch 10 (pilot clutch 11) is connected to each outer clutch plate 13 (18) and each outer clutch plate 13 (18). It is configured as a wet friction clutch in which lubricating oil is interposed between the inner clutch plate 14 (19). Specifically, each outer clutch plate 13 is spline-fitted to the inner periphery of the front housing 2 and each inner clutch plate 14 is spline-fitted to the outer periphery of the inner shaft 3, so that each outer clutch plate 13 can move in the axial direction and has a corresponding front. The housing 2 or the inner shaft 3 is provided so as to be integrally rotatable. Further, the lubricating oil is filled so that at least the entire friction sliding portion of the main clutch 10 at the lower part in the vertical direction is immersed, and the filling ratio of the lubricating oil with respect to the volume of the space in the front housing 2 is 10 to 90%. Is set to

  The main clutch 10 is configured such that the outer clutch plate 13 and the inner clutch plate 14 are pressed in the axial direction and frictionally engaged with each other, thereby coupling the front housing 2 and the inner shaft 3 so that torque transmission is possible. It is configured.

  On the other hand, the cam mechanism 12 can rotate integrally with the inner shaft 3 by being spline-fitted to the outer periphery of the first cam 15 that is rotatably provided by being supported on the inner shaft 3, The second cam 16 is provided so as to be movable in the axial direction, and the ball member 17 is interposed between the first cam 15 and the second cam 16.

  Both the first cam 15 and the second cam 16 are formed in a disk shape, the first cam 15 is disposed on the rear housing 6 side, and the second cam 16 is disposed on the main clutch 10 side. The outer peripheral surface of the first cam 15 is spline-fitted with an inner peripheral end of an inner clutch plate 19 of the pilot clutch 11 described later, and the second cam 16 is spline-fitted with the outer periphery of the inner shaft 3. A plurality of V-shaped grooves (not shown) inclined in the circumferential direction are formed on the opposing surfaces of the first cam 15 and the second cam 16 so as to oppose each other. It is clamped by the first cam 15 and the second cam 16 in a state of being arranged in the V-shaped groove. In the cam mechanism 12, when the first cam 15 and the second cam 16 rotate relative to each other, the first cam 15 and the second cam 16 are separated from each other, that is, the second cam 16 as a cam member is moved. The main clutch 10 is configured to move in the axial direction and press the main clutch 10.

  Further, the pilot clutch 11 as the second clutch, like the main clutch 10, is a multi-plate type in which a plurality of outer clutch plates 18 and inner clutch plates 19 provided so as to be movable in the axial direction are alternately arranged. The friction clutch is adopted. Specifically, each outer clutch plate 18 is spline-fitted to the inner periphery of the front housing 2 and the inner clutch plate 19 is spline-fitted to the outer periphery of the first cam 15, so that they can move in the axial direction and correspond to each other. The front housing 2 or the first cam 15 is provided so as to be rotatable together. The pilot clutch 11 connects the front housing 2 and the first cam 15 so that torque can be transmitted by the outer clutch plates 18 and the inner clutch plates 19 being pressed in the axial direction and frictionally engaged with each other. It is configured.

  Accordingly, the first cam 15 having the ball member 17 sandwiched between the second cam 16 is in a state of rotating together with the second cam 16, that is, the inner shaft 3 when the pilot clutch 11 is not operated. A rotation difference corresponding to the rotation difference between the front housing 2 and the inner shaft 3 is generated between the housing 2 and the first cam 15. The pilot clutch 11 is operated to connect the front housing 2 and the first cam 15 so that torque can be transmitted, and thereby torque based on the rotational difference between the front housing 2 and the inner shaft 3 (first cam 15). Is transmitted to the cam mechanism 12.

  That is, the driving force transmission device 1 transmits torque based on the rotational difference between the front housing 2 and the inner shaft 3 to the cam mechanism 12 by the operation of the pilot clutch 11, and the cam mechanism 12 generates the first cam generated by the torque. Based on the rotational difference between the first cam 15 and the second cam 16, the second cam 16 is moved to the axial main clutch 10 side. That is, the cam mechanism 12 converts torque based on the rotational difference between the front housing 2 and the inner shaft 3 transmitted via the pilot clutch 11 into axial pressing force. When the second cam 16 presses the main clutch 10, the main clutch 10 is operated, that is, the front housing 2 and the inner shaft 3 are connected so as to transmit torque.

  The pilot clutch 11 is configured as an electromagnetic clutch using the electromagnet 20 as a drive source. Specifically, the rear housing 6 is formed with an annular groove 21 that opens to the outside of the front housing 2 (on the side opposite to the front housing 2, the right side in FIG. 1). Is housed in. The rear housing 6 is provided with a cylindrical portion 6b extending from the center hole 6a in the axial direction to the front housing 2 side. The electromagnet 20 is connected to the rear housing by a ball bearing 22 provided in the cylindrical portion 6b. 6 (and front housing 2).

  Further, in the cylinder of the front housing 2, an annular armature 30 is arranged in the axial direction at a position where the outer clutch plate 18 and the inner clutch plate 19 are sandwiched between the armature 30 and the rear housing 6. The spline is slidably fitted. The pilot clutch 11 moves so that the armature 30 is attracted by the electromagnetic force of the electromagnet 20 and sandwiches the outer clutch plates 18 and the inner clutch plates 19 with the rear housing 6. The clutch plate 18 and the inner clutch plate 19 are configured to frictionally engage.

  As described above, the driving force transmission device 1 can control the operation (friction engagement force) of the pilot clutch 11 through power supply to the electromagnet 20. The operation of the main clutch 10, that is, the driving force that can be transmitted between the front housing 2 and the inner shaft 3 can be freely controlled through the operation of the pilot clutch 11.

(Arrangement suppression mechanism from the armature pilot clutch)
Next, a structure for suppressing the armature 30 from separating from the pilot clutch 11 will be described.

  A plurality of protrusions 32 are erected on the surface 31 opposite to the outer clutch plate 18 of the armature 30 formed in an annular shape. More specifically, as shown in FIG. 2, the same quadrangular pyramid-shaped protrusions 32 are erected at three rotationally symmetric positions around the axis of the armature 30. The radial slope 32 a of each protrusion 32 is formed by a plane inclined at an acute angle so as to approach the second cam 16 toward the outer side in the radial direction with respect to the opposite surface 31. Further, the circumferential inclined surface 32 b of each protrusion 32 is formed by a plane inclined at an acute angle with respect to the counter-facing surface 31 so as to approach the second cam 16 in the circumferential direction of the armature 30. Further, the height of the protrusion 32 is formed lower than the distance between the armature 30 and the second cam 16.

  When the front housing 2 is rotated at a high speed by the input of the driving force, as shown in FIG. 3, the lubricating oil accommodated in the front housing 2 is a centrifugal force generated by the rotation of the front housing 2, as indicated by an arrow Y1. Flowed radially outward. At this time, the lubricating oil collides with the radial inclined surface 32a of the armature 30 and biases the armature 30 toward the pilot clutch 11 side. More specifically, since the radial slope 32a is inclined with respect to the radial line of the armature 30, the lubricating oil flowed in the direction of the arrow Y1 hits the radial slope 32a and has a diameter as shown by the arrow Y2. The direction of the flow can be changed in the direction along the directional slope 32a. At this time, a force in a direction perpendicular to the radial inclined surface 32a is applied to the armature 30 from the lubricating oil. The armature 30 is applied with a force (in the direction of the white arrow in FIG. 3) for urging the axial pilot clutch 11 side, and the armature 30 moves to the pilot clutch 11 side.

  On the other hand, when the front housing 2 rotates at a relatively low speed, the lubricating oil is unevenly distributed downward in the front housing 2 due to gravity, so that the lubricating oil flows in the circumferential direction of the armature 30. For this reason, the armature 30 moves to the pilot clutch 11 side similarly to the case where the lubricating oil collides with the circumferential slope 32b of the armature 30 and collides with the radial slope 32a. Further, since the protrusions 32 are provided at three rotationally symmetric positions around the axis of the armature 30, the urging forces generated at the protrusions 32 are balanced and move toward the pilot clutch 11 without rattling. Can be moved smoothly.

  Since the armature 30 moves to the pilot clutch 11 side in this way, separation between the armature 30 and the pilot clutch 11 is suppressed. Therefore, when the armature 30 is attracted by the electromagnet 20, each outer clutch plate 18 and inner clutch plate 19 can be frictionally engaged. Therefore, the armature 30 can frictionally engage the outer clutch plates 18 and the inner clutch plates 19 without requiring time for the armature 30 to move to the pilot clutch 11 side, so that the response of the driving force transmission device 1 is reduced. Can be suppressed.

  Further, even when the transmission torque is reduced in accordance with the road surface condition where the vehicle travels, that is, even when the current supplied to the electromagnet 20 is reduced and the force for attracting the armature 30 is reduced, the electromagnet 20 is provided with the armature 30. Can be sucked and moved to the pilot clutch 11 side. Therefore, the armature 30 and the pilot clutch 11 are separated from each other, and the electromagnet 20 cannot move the armature 30 to the pilot clutch 11 side and cannot transmit torque. Can be suppressed.

  Further, when the armature 30 moves to the second cam 16 side due to the influence of the second cam 16 being magnetized due to the occurrence of magnetic flux leakage, the distance between the armature 30 and the second cam 16 becomes narrow, so the armature The flow speed of the lubricating oil flowing between 30 and the second cam 16 is increased, that is, the flow speed of the lubricating oil hitting the protrusion 32 is increased. Therefore, since the armature 30 is urged toward the pilot clutch 11 with a strong force, the armature 30 can be prevented from being separated from the pilot clutch 11. On the other hand, when the armature 30 approaches the outer clutch plate 18 side, the gap between the armature 30 and the second cam 16 becomes wide, so that the flow rate of the lubricating oil flowing between the armature 30 and the second cam 16 is slow. That is, the flow velocity of the lubricating oil that hits the protrusion 32 is reduced. Accordingly, the force with which the armature 30 is urged toward the pilot clutch 11 is weakened. Therefore, when the pilot clutch 11 is not operated, the armature 30 can reduce the distance between the outer clutch plate 18 and the inner clutch plate 19 and increase in the drag torque can be suppressed.

As described above, according to the present embodiment, the following effects can be obtained.
(1) Three quadrangular pyramidal protrusions 32 were erected at rotationally symmetric positions around the axis of the armature 30. A radial slope 32 a of each protrusion 32 is formed by a surface that is inclined at an acute angle with respect to the counter-facing surface 31 so as to approach the second cam 16 toward the radially outer side of the armature 30. Further, the circumferentially inclined surface 32 b of each protrusion 32 is formed by a surface inclined at an acute angle with respect to the opposite surface 31 so as to approach the second cam 16 in the circumferential direction of the armature 30. When the front housing 2 rotates at a high speed by the input of the driving force, the lubricating oil accommodated in the front housing 2 is caused to flow outward in the radial direction by the centrifugal force generated by the rotation of the front housing 2, and the lubricating oil is supplied to the armature. The armature 30 is urged toward the outer clutch plate 18 by striking the 30 radial slope 32a. On the other hand, when the front housing 2 rotates at a relatively low speed, the lubricating oil is unevenly distributed downward in the front housing 2 due to gravity. The armature 30 is urged toward the outer clutch plate 18 side. Since the armature 30 moves toward the pilot clutch 11 by being biased toward the outer clutch plate 18 in this way, the armature 30 and the pilot clutch 11 are prevented from being separated from each other, and the armature 30 operates. Deterioration of the responsiveness of the driving force transmission device 1 can be effectively suppressed without causing defects.

  (2) Since the protrusions 32 are erected at three rotationally symmetric positions around the axis of the armature 30, the urging forces generated by the protrusions 32 are balanced and do not rattle. The movement to is carried out smoothly.

  (3) When the armature 30 moves to the second cam 16 side, the flow rate of the lubricating oil that strikes the protrusion 32 increases, and therefore, the armature 30 is urged toward the outer clutch plate 18 with a strong force. It is possible to prevent the pilot clutch 11 from being separated further.

  (4) When the armature 30 moves to a position where it comes into contact with the outer clutch plate 18, the flow rate of the lubricating oil that strikes the protrusion 32 is reduced, and therefore the armature 30 is biased toward the outer clutch plate 18. Since the force becomes weak, an increase in drag torque can be suppressed.

In addition, you may implement each said embodiment in the following aspects.
-In this embodiment, although the protrusion 32 was provided in three places, if it is not restricted to this and the armature 30 moves along an axial direction, the number of the protrusions 32 may be fewer than three places, There may be more than three locations. Furthermore, in the present embodiment, the protrusions 32 are erected only in one row in the radial direction, but a plurality of rows may be erected.

  In the present embodiment, the protrusions 32 having the same shape are erected at rotationally symmetric positions around the axis of the armature 30, but the shapes of the protrusions may not be the same, and the rotationally symmetric positions It is not necessary to stand up.

  -In this embodiment, although the shape of the protrusion 32 was made into square pyramid shape, it is not restricted to this, The radial direction slope which changes the flow of the lubricating oil which flows to a radial direction outer side to the flow toward the 2nd cam 16 side And the protrusion which has at least one slope of the circumferential direction slope which changes the flow of the lubricating oil which flows along the circumferential direction into the flow which goes to the opposite direction of the pilot clutch 11 should just be used. For example, as shown in FIG. 4A, three triangular pyramid-shaped protrusions 42 are erected at rotationally symmetric positions around the axis of the armature 30, and a radial slope 42a and a circumferential slope 42b are provided. It may be formed.

  Further, as shown in FIG. 4B, the protrusion 52 is formed in a triangular prism shape, the side surface of the triangular prism and the counter-facing surface 31 are brought into contact with each other, and the remaining two side surfaces are circumferentially inclined surfaces 52b directed in the circumferential direction. May be erected. Furthermore, the protrusion 52 may be erected with the remaining side surface other than the side surface in contact with the opposite surface 31 facing in the radial direction. Thus, only one of the radial slope and the circumferential slope may be formed on the armature 30.

  In the present embodiment, the plurality of protrusions 32 are erected, but one protrusion may be formed over the entire circumference of the armature 30. For example, as shown in FIG. 4C, a projecting portion 62 having a triangular cross section may be provided in an annular shape over the entire circumference of the armature 30 to form a radial slope 62a.

  -In this embodiment, although the protrusion 32 was provided in the armature 30, it is not restricted to this, As shown in FIG.4 (d), the armature 30 becomes thin, so that it goes to a counter-facing surface 31 in radial direction inner side. The tapered surface 72 may be formed to form the radial slope 72a. By doing so, it is possible to generate a biasing force toward the outer clutch plate 18 without increasing the thickness of the armature 30, and the axial length of the driving force transmission device 1 can be shortened. Further, the protrusion 32 may be formed on the tapered surface 72. By doing in this way, the force urged | biased to the pilot clutch 11 side can be strengthened.

Sectional drawing of a driving force transmission device. The perspective view of an armature. The action figure which shows the flow of lubricating oil. (A)-(d) The perspective view of another armature.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Driving force transmission device, 2 ... Front housing, 3 ... Inner shaft, 10 ... Main clutch, 11 ... Pilot clutch, 12 ... Cam mechanism, 13, 18 ... Outer clutch plate, 14, 19 ... Inner clutch plate, 15 ... 1st cam, 16 ... 2nd cam, 20 ... Electromagnet, 30 ... Armature, 31 ... Anti-opposing surface, 32, 42, 52, 62 ... Projection, 32a, 42a, 62a, 72a ... Radial slope, 32b, 42b 52b, a circumferential slope, 72, a tapered surface.

Claims (4)

A cylindrical first rotating body that is rotated by an input of a driving force, an axial second rotating body that is coaxially disposed rotatably in the first rotating body, and the first rotating body and the second rotating body. A first clutch that is arranged in between and pressed in the axial direction to connect the first rotating body and the second rotating body so as to transmit torque; a second clutch juxtaposed in the axial direction of the first clutch; Torque based on the rotational difference between the first rotating body and the second rotating body, which is provided between the first clutch and the second clutch and is transmitted via the second clutch, is used as an axial pressing force. A cam mechanism that presses the first clutch by converting and moving the cam member in the axial direction; and a lubricating oil that is contained in the first rotating body at a predetermined filling rate, and the second clutch is driven Electromagnets that are the source, and multiple axially arranged An annular armature that is arranged in parallel with the latch plate and in the axial direction of the cam member so as to be axially movable at a position sandwiching the clutch plates between the electromagnets and to rotate integrally with the first rotating body. A driving force transmission device configured as an electromagnetic clutch that frictionally engages each clutch plate by a pressing force of the armature that is attracted and moved by the electromagnet,
On the surface of the armature opposite to the clutch plate, a radially inclined surface that is inclined so as to approach the cam member side toward the radially outer side of the armature, and the cam member side in the circumferential direction of the armature A driving force transmission device, wherein at least one of slopes in the circumferential direction inclined so as to approach is formed. The driving force transmission device according to claim 1,
At least one of the radial slope and the circumferential slope is formed by a protrusion standing on the opposite surface. The driving force transmission device according to claim 2,
The drive force transmission device according to claim 1, wherein the protrusions having the same shape are formed at rotationally symmetrical positions around the axis of the armature on the opposite surface. The driving force transmission device according to claim 1,
The driving force transmission device according to claim 1, wherein the radial slope is formed by tapering the armature so that a plate thickness of the armature decreases from a radially outer side toward a radially inner side.

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