JP5706591B2 - Power transmission device, clutch device, and drive device - Google Patents

Description

  The present invention relates to a power transmission device, a clutch device, and a drive device capable of transmitting power between a first power transmission member and a second power transmission member.

  Generally, an operation member that operates in a predetermined direction is provided in a vehicle. The power of the actuator or the operating force of the operator is transmitted to the operating member via the first power transmission member and the second power transmission member. In addition, a clutch device may be provided as a power transmission device that prevents power applied from the operating member to the second power transmission member from being transmitted to the first power transmission member. An example of a sheet apparatus having this is described in Patent Document 1.

  The vehicle seat device described in Patent Literature 1 transmits the operating force of an operator to a seat (operation member) to adjust the height. The seat device includes an operation lever operated by an operator and an operation shaft (first power transmission member) through which an operation force of the operation lever is transmitted. The seat device also includes an output shaft (second power transmission member) that transmits power from the operation shaft, and a pinion gear provided on the output shaft. Further, the seat device has a sector gear and a link mechanism for transmitting the power transmitted to the pinion gear to the seat.

  The seat device has a cylindrical housing, and the operation shaft and the output shaft are coaxially arranged in the housing. The operation shaft and the output shaft are configured to be capable of relative rotation. Further, the seat device has a power transmission path for transmitting the operation force (power) transmitted to the operation shaft to the output shaft when the operation lever is operated.

  Further, the seat device has a clutch device. The clutch device is a mechanism that prevents the power of the output shaft from being transmitted to the operation shaft while transmitting the power of the operation shaft to the output shaft. The clutch device is interposed between a brake cam provided to rotate integrally with the output shaft, a control plate rotatably attached to the output shaft, and an inner peripheral surface of the housing and an outer peripheral surface of the brake cam. And a locking spring that presses the roller. Furthermore, the clutch device has a braking spring. The braking spring is attached to a washer fixed to the output shaft, and the braking spring is always pressed against the inner peripheral surface of the housing.

  In the seat device configured as described above, an operation of rotating the operation lever between the neutral position and the upper position or between the neutral position and the lower position is performed. In the seat device, when power is transmitted from the operation lever to the operation shaft, the control plate rotates and pushes the roller, and it is eliminated that the seat device bites between the housing and the brake cam. That is, the lock that prevents the rotation of the brake cam is released. For this reason, the power of the control plate is transmitted to the output shaft via the brake cam, and the seat is raised or lowered. In the sheet apparatus, when the operation lever is stopped at the neutral position, the height of the sheet is fixed.

  On the other hand, when the operation lever is not operated and the seat is moved and the power is transmitted to the output shaft, the roller bites between the outer peripheral surface of the brake cam and the inner peripheral surface of the housing. For this reason, the brake cam is locked, and the brake cam cannot be rotated. In this way, the power of the output shaft can be prevented from being transmitted to the operation shaft.

  Furthermore, in the clutch device described in Patent Document 1, the brake spring is constantly pressed against the inner peripheral surface of the housing. For this reason, the brake springs indicate that the seat height changes from the time when the operation lever is operated and the brake cam is unlocked until the power of the control plate is transmitted to the brake cam. It can be prevented by the frictional force between the housing and the inner peripheral surface of the housing.

JP 2010-255837 A

  However, in the power transmission device described in Patent Document 1, both the locking spring and the braking spring are provided, and there is a problem that the number of parts increases.

  An object of the present invention is to provide a power transmission device, a clutch device, and a drive device capable of reducing the number of parts.

  The power transmission device of the present invention is provided in the first power transmission member along a circumferential direction around the axis, and a first power transmission member and a second power transmission member that can rotate around the axis. A plurality of support shafts, a plurality of movable pieces rotatably supported by the plurality of support shafts, each having a curved surface that gradually increases as the distance from the support shaft reaches the end, and the second power A plurality of locking claws provided on the transmission member and engaged with the plurality of movable pieces, respectively, and a fixed portion provided on the outer side of the plurality of movable pieces in the radial direction about the axis. An elastic member having a member, a sliding portion that slides with the fixed member, and a movable piece holding portion that holds the movable piece, and the curved surface of the movable piece is Power transmission device that is held in a position that does not contact the fixed member When the torque transmitted between the first power transmission member and the second power transmission member exceeds a threshold value, the movable piece is supported against the movable piece holding portion of the elastic member. Rotating about an axis, the curved surface comes into contact with the fixed member to generate a braking force, and no torque is transmitted between the first power transmission member and the second power transmission member. .

  In the power transmission device of the present invention, when the torque transmitted between the first power transmission member and the second power transmission member is a threshold value or less, the plurality of movable pieces and the plurality of locking claws Torque is transmitted between the first power transmission member and the second power transmission member by the engaging force.

  The elastic member in the power transmission device of the present invention has a plurality of engaging portions that respectively engage with the plurality of locking claws, and transmits between the first power transmission member and the second power transmission member. When the torque to be applied is equal to or less than a threshold value, the engagement force between the plurality of engagement portions and the plurality of locking claws, and the engagement force between the plurality of movable pieces and the plurality of movable piece holding portions, Torque is transmitted between the first power transmission member and the second power transmission member.

  The drive device of the present invention is a drive device in which the power of the electric motor is transmitted to the second power transmission member via the first power transmission member, wherein the first power transmission member, the second power transmission member, The power transmission device described above is provided between the two.

  The clutch device of the present invention is provided with a first power transmission member and a second power transmission member that are rotatable about a first axis, and power is provided between the first power transmission member and the second power transmission member. A clutch device that switches between a state in which power transmission can be performed and a state in which power transmission cannot be performed, and is a facing surface that faces the second power transmission member in a radial direction about the first axis A ring-shaped fixing member having a protrusion, a protrusion provided on the second power transmission member and projecting toward the fixing member in a radial direction centered on the first axis, and a radius centered on the first axis A movable piece disposed between the second power transmission member and the fixed member in a direction and rotatably attached to the first power transmission member about a second axis parallel to the first axis. , Provided on the movable piece And the 1st contact part which contacts the said protrusion part, the 2nd contact part which is provided in the said movable piece, and contacts the said fixing member, The force of the direction along the said 2nd axis on the said movable piece The first contact portion is in contact with the protruding portion, and the second contact portion is provided with a force applying member that maintains a state in contact with the inner peripheral surface of the fixing member. Features.

  The drive device of the present invention is a drive device in which the power of the electric motor is transmitted to the second power transmission member via the first power transmission member, wherein the first power transmission member, the second power transmission member, A clutch device that switches between a state in which power transmission can be performed and a state in which power transmission cannot be performed is provided, and the clutch device has the configuration of the clutch device of the present invention.

  The drive device of the present invention is provided with a first power transmission member and a second power transmission member that are rotatable about a first axis, and power is provided between the first power transmission member and the second power transmission member. A clutch device that switches between a state in which power transmission can be performed and a state in which power transmission cannot be performed, and is a facing surface that faces the second power transmission member in a radial direction about the first axis A ring-shaped fixing member having a protrusion, a protrusion provided on the second power transmission member and projecting toward the fixing member in a radial direction centered on the first axis, and a radius centered on the first axis A movable piece disposed between the second power transmission member and the fixed member in a direction and rotatably attached to the first power transmission member about a second axis parallel to the first axis. , Provided on the movable piece, One, a first contact portion that contacts the protruded portion, provided on the movable piece, and characterized in that it comprises a second contact portion in contact with the fixing member.

  According to the power transmission device of the present invention, only one type of elastic member is required, and the number of parts can be reduced.

  According to the power transmission device of the present invention, when the torque transmitted between the first power transmission member and the second power transmission member is equal to or lower than the threshold value, the relationship between the plurality of movable pieces and the plurality of locking claws is achieved. Torque is transmitted between the first power transmission member and the second power transmission member by the resultant force.

  According to the power transmission device of the present invention, when the transmission torque between the first power transmission member and the second power transmission member is equal to or less than the threshold value, the engagement force between the engagement portion and the locking claw, and a plurality of Torque is transmitted between the first power transmission member and the second power transmission member by the engaging force between the movable piece and the plurality of movable piece holding portions.

  According to the clutch device of the present invention, only one type of force applying member is required, and the number of parts can be reduced. Further, when power is generated in a direction in which the first power transmission member rotates about the first axis, the second contact portion moves along the fixed member in a state where the second contact portion is in contact with the fixed member. In addition, power is transmitted to the second power transmission member via a contact portion between the first contact portion and the protruding portion. In addition, a force in the direction along the second axis from the force applying member is constantly applied to the movable piece, the first contact portion contacts the protruding portion, and the second contact portion contacts the inner peripheral surface of the fixed member. Maintained.

  Therefore, when the power of the first power transmission member is not transmitted to the second power transmission member, when the power of the first power transmission member is switched to the state of transmitting the power to the second power transmission member, the power is transiently changed. It is possible to prevent the state from not being transmitted. Further, since the force in the direction along the second axis from the force applying member is applied to the movable piece, the frictional force at the contact portion between the second contact portion and the fixed member does not increase, and the power of the first power transmission member is increased. When transmitting to the 2nd power transmission member, it can control that power transmission efficiency falls. In addition, power is transmitted without causing a time difference between the time when the condition for transmitting the power of the first power transmission member to the second power transmission member is established and the time when power transmission is actually started. Can do.

  According to the driving device of the present invention, only one kind of force applying member is required, and the number of parts can be reduced. Further, when power is not transmitted from the electric motor to the first power transmission member, it is possible to avoid the external force applied to the second power transmission member being transmitted to the electric motor via the first power transmission member. .

  According to the drive device of the present invention, when power is generated in a direction in which the first power transmission member rotates around the first axis, the second contact portion is in the state where the second contact portion is in contact with the fixed member. Move along. In addition, power is transmitted to the second power transmission member via a contact portion between the first contact portion and the protruding portion.

It is a top view of the drive device which has a power transmission device of the present invention. It is a front view of the drive device which has a power transmission device of the present invention. It is front sectional drawing of the power transmission device of this invention. It is a disassembled perspective view of the power transmission device of this invention. It is a top view of the power transmission device of the present invention. It is a top view of the power transmission device of the present invention. It is the top view which removed the elastic member of the power transmission device shown in FIG. It is a disassembled perspective view of the power transmission device shown in FIG. It is a top view of the drive device of the present invention. It is front sectional drawing of the clutch apparatus of this invention. It is a disassembled perspective view of the clutch apparatus of this invention. It is a top view of the clutch apparatus of this invention. It is a schematic diagram which shows the structure of the clutch apparatus of this invention. It is a schematic diagram which shows another structure of the clutch apparatus of this invention.

(Embodiment 1)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. The drive device 10 shown in FIGS. 1 to 5 is a mechanism for operating an operation member such as a seat back and a seat cushion provided in the vehicle. The drive device 10 includes an electric motor 11. The electric motor 11 has a plurality of permanent magnets (not shown) and an armature 12. The electric motor 11 has a cylindrical yoke 13, and a plurality of permanent magnets are fixed to the inner peripheral surface of the yoke 13. The armature 12 has an electromagnetic coil (not shown) and a commutator (not shown), and the armature 12 is attached to the armature shaft 14. The electric motor 11 has a brush (not shown) that comes into contact with the armature shaft 14. The electric motor 11 is supplied with electric power through the brush to the electromagnetic coil to form a rotating magnetic field, and the armature shaft 14. Is configured to rotate. The electric motor 11 can rotate the armature shaft 14 forward or backward. The electric motor 11 is switched from stop to rotation when a condition for operating the operation member, for example, a switch (not shown) or the like is operated.

  A gear case 15 is fixed to the yoke 13, and an opening 15 a of the gear case 15 is closed by a cover 16. In FIG. 1, the cover 16 is not shown for convenience. The cover 16 is fixed to the gear case 15 by a fixing element such as a screw. The armature shaft 14 is disposed from the inside of the yoke 13 to the inside of the gear case 15. The armature shaft 14 is rotatably supported with respect to each of the yoke 13 and the gear case 15 by a bearing (not shown).

  A worm 14 a is formed on the outer peripheral surface of a portion of the armature shaft 14 disposed inside the gear case 15. Inside the gear case 15 is provided a worm wheel 18 that can rotate around a support shaft 17 fixed to the gear case 15. A gear 18a is formed on the entire circumference of the worm wheel 18, and the gear 18a is engaged with the worm 14a. A reduction mechanism 19 is constituted by the gear 18a and the worm 14a. The speed reduction mechanism 19 is a mechanism that makes the rotational speed of the worm wheel 18 slower than the rotational speed of the armature shaft 14 when power is transmitted from the armature shaft 14 to the worm wheel 18. A gear 20 coaxial with the worm wheel 18 is provided on the outer periphery of the support shaft 17. The gear 20 rotates integrally with the worm wheel 18. The number of teeth of the gear 20 is smaller than the number of teeth of the gear 18 a of the worm wheel 18. As shown in FIG. 3, the gear 20 is disposed at a position different from the worm wheel 18 in the direction along the rotation center of the support shaft 17, that is, in the direction along the axis A in FIG. 3. More specifically, the gear 20 is disposed between the cover 16 and the worm wheel 18 in a direction along the axis A.

  The gear case 15 is provided with a gear case through hole 15b centering on the axis B shown in FIG. 3 and rotatably supporting the output shaft 21. The output shaft 21 is disposed from the inside of the gear case 15 to the outside via the gear case through hole 15b. Further, the cover 16 is provided with a through hole 16a centering on the axis B in FIG. The output shaft 21 is disposed through the through hole 16 a and is rotatable relative to the cover 16 and the gear case 15. The output shaft 21 is configured not to move in the direction along the axis B with respect to the cover 16 and the gear case 15. The output shaft 21 has a cylindrical shape with the axis B as the center, and an inner tooth 21 b is provided on the inner peripheral surface of the shaft hole 21 a of the output shaft 21. A power transmission shaft (not shown) is splined or serrated to the shaft hole 21a of the output shaft 21, and the rotational force (torque) of the output shaft 21 is transmitted to the power transmission shaft. The power transmission shaft is connected to other power transmission elements such as a gear, a shaft, a lever, a link and the like so as to be able to transmit power. The axis B is substantially the same as the rotation center line of the output shaft 21.

  The output shaft 21 has a circular outer peripheral shape in a plane perpendicular to the axis B. Further, three locking claws 32 are provided on the outer peripheral surface of the output shaft 21. The three locking claws 32 are provided at equal intervals along the circumferential direction of the output shaft 21. The three locking claws 32 protrude outward from the outer peripheral surface of the output shaft 21. Moreover, the recessed part 33 is provided between the latching claws 32, respectively.

  An output wheel 23 is provided inside the gear case 15. The output wheel 23 is arranged coaxially with the output shaft 21 around the axis B. A shaft hole 23 a is provided at the center of the output wheel 23. The shaft hole 23a has a circular shape centered on the axis B, and the output shaft 21 is inserted into the shaft hole 23a. The output wheel 23 is disposed between the cover 16 and the worm wheel 18 in a direction along the axis B. The output wheel 23 and the output shaft 21 are relatively rotatable. A gear 23 b is formed on the outer peripheral surface of the output wheel 23, and the gear 23 b is engaged with the gear 20. The number of teeth of the gear 23b is larger than the number of teeth of the gear 20. That is, when power is transmitted from the gear 20 to the output wheel 23, the rotational speed of the output wheel 23 is lower than the rotational speed of the gear 20. That is, the two gears 20 and 23 b constitute a speed reduction mechanism 24.

  A pin 34 is fixed to the output wheel 23. A plurality of, specifically three, pins 34 are fixed on the same circumference around the axis B. As shown in FIG. 4, the output wheel 23 is provided with three holes 35 on the same circumference around the axis B. The hole 35 may be formed so as to penetrate the output wheel 23 in the direction along the axis B, or may not penetrate in the direction along the axis B. The three holes 35 are arranged at equal intervals on the circumference around the axis B. A pin 34 is inserted into each hole 35 and fixed. The three pins 34 are arranged outside the output shaft 21 in the radial direction centered on the axis B. Further, the outer peripheral shape of the pin 34 in a plane perpendicular to the axis B is circular. In this manner, when the output wheel 23 rotates with the three pins 34 attached to the output wheel 23, the three pins 34 can revolve around the axis B.

  On the other hand, a bracket 26 is fixed to the cover 16. A shaft hole 26 c is provided in the bracket 26. Further, a ring 36 is provided around the axis B, and the output shaft 21 is inserted into the inside of the ring 36 and the shaft hole 26c. Further, the ring 36 is formed with an inner peripheral surface 37 as a facing surface facing the output shaft 21. The ring 36 is fixed in the through hole 16 a of the cover 16. The cover 16 and the bracket 26 are configured not to rotate relative to each other about the axis B in a state where the ring 36 is assembled to the through hole 16a. The end surface of the ring 36 and the side surface of the output wheel 23 are not in contact with each other.

  Cams 38 are rotatably supported by the three pins 34 described above. The cam 38 is capable of rotating around the axis E of the pin 34 while being attached to the pin 34. Further, the cam 38 can revolve around the axis B together with the pin 34 when the output wheel 23 rotates. The three cams 38 are each integrally formed of metal. Each cam 38 approximates a shape in which three sides of an equilateral triangle are expanded outward. Specifically, two curved surfaces 39 and one curved surface 40 are provided on the outer periphery of each cam 38. Of the three curved surfaces 39, 40, the curved surface 40 is disposed on the outermost periphery in the radial direction of the output shaft 21.

  A corner 41 is provided between the two curved surfaces 39, and the surface of the corner 41 is curved with a larger curvature than the curved surfaces 39 and 40. In addition, corner portions 42 are provided between the curved surface 40 and the curved surface 39, respectively. The corner 42 is disposed outside the corner 41 in the radial direction of the output shaft 21. The linear distance from the vertex of the corner portion 41 to the vertex of the corner portion 42 is longer than the distance from the bottom of the recess 33 to the inner peripheral surface 37 of the ring 36 in the radial direction of the output shaft 21. One corner 41 provided in each of the three cams 38 is disposed in each of the three recesses 33.

  Further, one elastic member 43 is arranged between the ring 36 and the output shaft 21 and between the cams 38 adjacent in the circumferential direction. The elastic member 43 includes a first arc part 44, a second arc part 45 as a sliding part, and a connection part 46 as a movable piece holding part that is continuous with the first arc part 44 and the second arc part 45. Have. The first arc portion 44 is arranged inside the second arc portion 45 in the radial direction of the output shaft 21. The connecting portion 46 connects the end portion of the first arc portion 44 in the circumferential direction and the end portion of the second arc portion 45 in the circumferential direction. The circumferential length of the first arc portion 44 is shorter than the circumferential length of the second arc portion 45. The three elastic members 43 are each formed of a metal plate, and the three elastic members 43 are subjected to spring treatment. The three elastic members 43 are compression springs that generate a repulsive force against a circumferential force.

  The connection portions 46 of the two elastic members 43 are pressed against the two curved surfaces 39 of one cam 38, respectively. That is, the cam 38 is sandwiched from both sides in the circumferential direction by the two elastic members 43 in a state where the corner portion 41 is disposed in the concave portion 33. For this reason, the cam 38 is prevented from rotating around the pin 34. Further, in a state where the cam 38 is prevented from rotating around the pin 34, a gap is formed between the curved surface 40 and the inner peripheral surface 37 of the ring 36 and is not in contact with each other.

  The pin 34, the cam 38, the ring 36, the elastic member 43, the recess 33, and the locking claw 32 constitute a power transmission device 47 of the present invention.

  When the torque of the electric motor 11 is not transmitted to the output wheel 23 and no external force is applied to the output shaft 21, the posture of the cam 38 is maintained by the elastic member 43. That is, the cam 38 is held at a neutral position where the corner portion 41 is disposed in the recess 33 and the curved surface 40 is not in contact with the inner peripheral surface 37 of the ring 36.

  On the other hand, when the torque of the electric motor 11 is transmitted to the output wheel 23 in a state where the cam 38 is held at the neutral position by the elastic member 43, the torque of the output wheel 23 is changed to the pin 34, the cam 38, and the locking claw. It is transmitted to the output shaft 21 via 32. Therefore, even if the output wheel 23 rotates in either the clockwise direction or the counterclockwise direction in FIGS. 1 and 5, the torque of the output wheel 23 is transmitted to the output shaft 21. Further, when the torque of the output wheel 23 is equal to or less than the threshold value, the elastic member 43 is elastically deformed in the range of the gap formed between the curved surface 40 and the inner peripheral surface 37 of the ring 36. That is, the curved surface 40 is held in a state of not contacting the inner peripheral surface 37 of the ring 36.

  On the other hand, when the torque of the output wheel 23 exceeds the threshold value, the elastic member 43 is elastically deformed, and the cam 38 is inclined in any direction from the neutral position with the corner portion 41 as a fulcrum. As a result, the curved surface 40 of the cam 38 is pressed against the inner peripheral surface 37 of the ring 36 to generate a braking force, and the output wheel 23 is prevented from rotating. That is, torque is not transmitted from the output wheel 23 to the output shaft 21.

  On the other hand, when torque is transmitted from the power transmission shaft to the output shaft 21 in a state where the cam 38 is held at the neutral position by the elastic member 43 and the electric motor 11 is stopped, the engagement claw 32 and the corners of the engaging claw 32 are Due to the engaging force with the portion 41, the torque of the output shaft 21 is transmitted to the output wheel 23 via the cam 38 and the pin 34. Here, even if the output wheel 23 rotates in either the clockwise direction or the counterclockwise direction in FIGS. 1 and 5, the torque of the output wheel 23 is transmitted to the output shaft 21. If the torque transmitted from the power transmission shaft to the output shaft 21 is equal to or less than the threshold value, the elastic member 43 is not elastically deformed and the curved surface 40 is held in a state where it is not in contact with the inner peripheral surface 37 of the ring 36. The

  On the other hand, when a sudden load is applied to the seat and the torque transmitted from the power transmission shaft to the output shaft 21 exceeds a threshold value, the elastic member 43 is elastically deformed, and the cam 38 tilts with the corner portion 41 as a fulcrum. . As a result, the curved surface 40 of the cam 38 is pressed against the inner peripheral surface 37 of the ring 36 to generate a braking force, thereby preventing the output shaft 21 from rotating. That is, torque is not transmitted from the output shaft 21 to the output wheel 23.

  Further, in the power transmission device 47, when the torque transmitted between the output wheel 23 and the output shaft 21 exceeds a threshold value, the elastic member 43 is elastically deformed, and the second arcuate portion 45 becomes the inner peripheral surface of the ring 36. 37, and the first arc portion 44 is pressed against the outer peripheral surface of the locking claw 32. Accordingly, the frictional force between the elastic member 43 and the ring 36 and the frictional force between the elastic member 43 and the locking claw 32 act on the output shaft 21 as a braking force. Note that the elastically deformed elastic member 43 is restored to its original shape when the transmitted torque is less than or equal to the threshold value.

  The principle of generation of braking force in the power transmission device 47 is as follows. The distance between the center position of the pin 34 and the center position in the circumferential direction of the curved surface 40 of the cam 38 is set smaller than the distance between the center position of the pin 34 and the inner peripheral surface 37 of the ring 36. In addition, the distance between the center position of the pin 34 and the end portion in the circumferential direction of the curved surface 40 of the cam 38 is set larger than the distance between the center position of the pin 34 and the inner peripheral surface 37 of the ring 36. . Therefore, when the cam 38 is held at the neutral position, a gap is formed between the curved surface 40 of the cam 38 and the inner peripheral surface 37 of the ring 36. On the other hand, when the cam 38 tilts around the pin 34 from the neutral position, the curved surface 40 of the cam 38 comes into sliding contact with the inner peripheral surface 37 of the ring 36 and generates a braking force.

  As described above, the power transmission device 47 is a clutch device that transmits power between the output wheel 23 and the output shaft 21. Further, when the torque transmitted between the output wheel 23 and the output shaft 21 is equal to or less than the threshold value, the torque is transmitted, while on the other hand, when the torque transmitted between the output wheel 23 and the output shaft 21 exceeds the threshold value. It has a role as a torque limiter that does not transmit torque.

  Furthermore, the power transmission device 47 prevents reverse rotation of the output wheel 23 when a sudden load is applied to the seat and the torque transmitted from the power transmission shaft to the output shaft 21 exceeds a threshold value. It serves as a reverse rotation prevention device.

  Further, since the power transmission device 47 only uses one type of elastic member 43, the number of parts can be reduced, and the number of assembling steps of the power transmission device 47 can be reduced. Further, the elastic member 43 may be disposed between the ring 36 and the output shaft 21 and between the cams 38, and the assembly work of the elastic member 43 is easy.

  Further, torque is transmitted between the output wheel 23 and the output shaft 21 in a state where the curved surface 40 of the cam 38 is separated from the inner peripheral surface 37 of the ring 36. That is, sliding between the inner peripheral surface 37 of the ring 36 and the cam 38 can be prevented. For this reason, when transmitting torque from the output wheel 23 to the output shaft 21, power loss can be suppressed.

  When torque is transmitted between the output wheel 23 and the output shaft 21, the connecting portion 46 of the elastic member 43 is pressed against the curved surface 39 of the cam 38, and the posture of the cam 38 is maintained. Therefore, the cam 38 does not swing around the pin 34, and the corner portion 41 can be prevented from colliding with the locking claw 32 and generating noise. The elastic member 43 according to the first embodiment is elastically deformed in the radial direction of the output shaft 21 by pressing the two cams 38 against the two connecting portions 46.

  The torque threshold in the first embodiment is an artificially determined value, and the torque threshold can be arbitrarily changed by changing the rigidity of the elastic member 43. In the first embodiment, since a metal leaf spring is used as the elastic member 43, the torque threshold is determined by the spring constant. For example, the higher the rigidity of the elastic member 43, the higher the torque threshold.

  Here, the correspondence between the configuration of the first embodiment and the present invention will be described. The axis B corresponds to the axis of the present invention, the output wheel 23 corresponds to the first power transmission member of the present invention, and the output. The shaft 21 corresponds to the second power transmission member of the present invention, the pin 34 corresponds to the support shaft of the present invention, the cam 38 corresponds to the movable piece of the present invention, and the ring 36 corresponds to the fixed shaft of the present invention. It corresponds to a member.

(Embodiment 2)
Next, a second embodiment of a power transmission device that can be used in the drive device 10 shown in FIG. 1 will be described with reference to FIGS. That is, the power transmission device 48 in the second embodiment can be used in the drive device 10 instead of the power transmission device 47 in the first embodiment. 6 to 8, the same components as those in FIGS. 1 to 5 are denoted by the same reference numerals as those in FIGS.

  The power transmission device 48 according to the second embodiment includes an elastic member 49 and a cam 50 in addition to the output wheel 23 and the output shaft 21. A plurality of cams 50, specifically three, are provided, and the three cams 50 are respectively attached to the output wheel 23 via pins 51. The three pins 51 are press-fitted and fixed in holes 35 formed in the output wheel 23. The three cams 50 are each formed of metal, and the three cams 50 can rotate about the pin 51, respectively. The three pins 51 are arranged at equal intervals on the same circumference around the axis B. The three pins 51 are provided around the axis E, respectively.

  Since the three cams 50 have the same shape, only one cam 50 will be described for convenience. The cam 50 has a thick portion 50a having a long length in the direction along the axis E and a thin portion 50b having a short length. The cam 50 is attached to the pin 51 so that the thick portion 50a is disposed outside the thin portion 50b in the radial direction about the axis B. Moreover, the cam 50 has the convex part 50c which follows the thin part 50b. The convex part 50c protrudes inward from the innermost periphery of the thin part 50b. The convex portion 50 c is disposed in the concave portion 33 of the output shaft 21. Depending on the position of the cam 50 around the pin 51, a gap is formed between the end 50 d of the convex portion 50 c and the end 32 a of the locking claw 32 in the circumferential direction around the axis B. The The curved surface 50e provided on the outer periphery of the cam 50 has an arc shape on a plane perpendicular to the axis E.

  On the other hand, the elastic member 49 is integrally formed by a plate-shaped metal spring, and the elastic member 49 is supported so as not to move in the direction along the axis B. The elastic member 49 is attached to the outer periphery of the output shaft 21, and the elastic member 49 includes an annular portion 52 formed in an annular shape, and three third engaging portions provided on the inner periphery of the annular portion 52. As one engaging convex part 53, two sets of second engaging convex parts 54 as a movable piece holding part provided on the outer periphery of the annular part 52, and a sliding part provided on the outer periphery of the annular part 52 And three arms 55.

  The annular portion 52 is disposed outside the locking claw 32, and the three first engaging convex portions 53 are separately press-fitted and fixed to the three concave portions 33 of the output shaft 21. For this reason, the elastic member 49 and the output shaft 21 can rotate integrally. The arm 55 extends outward from the outer periphery of the annular portion 52 and is curved in a vortex shape. The arm 55 is pressed against the inner peripheral surface 37 of the ring 36. The elastic member 49 exhibits an elastic force in the circumferential direction and the radial direction around the axis B.

  Three sets of two sets of second engaging convex portions 54 are provided. The two sets of second engaging projections 54 are arranged on both sides of one cam 50 in the circumferential direction centering on the axis B, and the two sets of second engaging projections 54. The radial tip centered on the axis B is arranged on the side of the thick portion 50a in the circumferential direction centered on the axis B, thereby holding the cam 50 in the neutral position. Further, the portion of the annular portion 52 between the two second engagement convex portions 54 is disposed so as to overlap the thin portion 50b.

  Since the cam 50 is sandwiched on both sides in the circumferential direction by a pair of second engaging projections 54, rotation of the cam 50 around the pin 51 is suppressed. Further, when the cam 50 is prevented from rotating around the pin 51, a gap is formed between the curved surface 50e and the inner peripheral surface 37 of the ring 36, and is not in contact with each other.

  Next, an operation when the power transmission device 48 in the second embodiment is used in the drive device 10 will be described. Here, the case where the torque of the electric motor 11 is transmitted to the output wheel 23 via the gear 20 and the torque in the direction of rotating the output wheel 23 counterclockwise in FIGS. 6 and 7 will be described as an example. When the torque transmitted to the output wheel 23 is equal to or less than the threshold value, the amount of elastic deformation of the second engagement convex portion 54 that receives the force of the cam 50 is very small.

  For this reason, a gap is secured between the end 50d of the convex portion 50c and the end 32a of the locking claw 32, and the cam 50 is held in the neutral position. That is, the curved surface 50 e of the cam 50 does not contact the inner peripheral surface 37 of the ring 36. Therefore, the torque transmitted from the pin 51 to the cam 50 is transmitted to the elastic member 49 via the second engagement convex portion 54, and the force is applied between the first engagement convex portion 53 and the locking claw 32. The resultant force is transmitted to the output shaft 21. As described above, the power transmission device 48 transmits the torque of the output wheel 23 to the output shaft 21 via the cam 50 and the elastic member 49.

  On the other hand, when the torque transmitted to the output wheel 23 exceeds the threshold value, the second engagement convex portion 54 that receives the force of the cam 50 is elastically deformed. Then, the cam 50 and the output shaft 21 are relatively rotated in the circumferential direction within a minute angle range, and the end portion 50d of the convex portion 50c and the end portion 32a of the locking claw 32 come into contact with each other. As a result, the cam 50 rotates counterclockwise around the pin 51 within a predetermined angle range, the curved surface 50e of the cam 50 contacts the inner peripheral surface 37 of the ring 36, and a braking force is generated. In this way, the power transmission device 48 does not transmit torque from the output wheel 23 to the output shaft 21.

  Furthermore, an operation when the torque of the output shaft 21 is transmitted to the output wheel 23 will be described.

  Here, the case where the torque of the direction which rotates the output shaft 21 counterclockwise with FIG. 6, FIG. 7 arises is demonstrated as an example. The torque of the output shaft 21 is transmitted to the elastic member 49 by the engaging force between the locking claw 32 and the first engaging convex portion 53. When the torque transmitted to the elastic member 49 is equal to or less than the threshold value, the amount of elastic deformation of the second engagement convex portion 54 that comes into contact with the thick portion 50a of the cam 50 is very small.

  For this reason, a gap is secured between the end 50d of the convex portion 50c and the end 32a of the locking claw 32, and the cam 50 is held in the neutral position. That is, the curved surface 50 e of the cam 50 does not contact the inner peripheral surface 37 of the ring 36. Therefore, the force transmitted from the elastic member 49 to the cam 50 is transmitted to the output wheel 23 via the pin 51. As described above, the power transmission device 48 can transmit the torque of the output shaft 21 to the output wheel 23 via the elastic member 49 and the cam 50.

  On the other hand, when the torque of the output shaft 21 exceeds the threshold value, the second engaging convex portion 54 pressed against the cam 50 is elastically deformed. Then, the cam 50 rotates clockwise around the pin 51 within a small angle range, and the end 50d of the convex portion 50c and the end 32a of the locking claw 32 come into contact with each other. As a result, the curved surface 50e of the cam 50 comes into contact with the inner peripheral surface 37 of the ring 36, and a braking force is generated. In this way, the power transmission device 48 does not transmit torque from the output shaft 21 to the output wheel 23.

  The principle of generation of the braking force in the power transmission device 48 is as follows. The distance between the center position of the pin 51 and the center position in the circumferential direction of the curved surface 50 e of the cam 50 is set smaller than the distance between the center position of the pin 51 and the inner peripheral surface 37 of the ring 36. In addition, the distance between the center position of the pin 51 and the end portion in the circumferential direction of the curved surface 50 e of the cam 50 is set to be larger than the distance between the center position of the pin 51 and the inner peripheral surface 37 of the ring 36. . Therefore, in the state where the cam 50 is held at the neutral position, a gap is formed between the curved surface 50 e of the cam 50 and the inner peripheral surface 37 of the ring 36. On the other hand, when the cam 50 tilts around the pin 51 from the neutral position, the curved surface 50e of the cam 50 comes into sliding contact with the inner peripheral surface 37 of the ring 36 and generates a braking force.

  As described above, the power transmission device 48 is a clutch device that transmits power between the output wheel 23 and the output shaft 21. Further, when the torque transmitted between the output wheel 23 and the output shaft 21 is equal to or less than the threshold value, the torque is transmitted, while on the other hand, when the torque transmitted between the output wheel 23 and the output shaft 21 exceeds the threshold value. It has a role as a torque limiter that does not transmit torque.

  Furthermore, the power transmission device 48 prevents reverse rotation of the output wheel 23 when a sudden load is applied to the seat and the torque transmitted from the power transmission shaft to the output shaft 21 exceeds a threshold value. It serves as a reverse rotation prevention device.

  Further, since the power transmission device 48 is limited to using one type of elastic member 49, the number of parts can be reduced, and the number of assembling steps of the power transmission device 48 can be reduced. Furthermore, the elastic member 49 may be disposed between the ring 36 and the output shaft 21 and between the cams 50, and the assembly operation of the elastic member 49 is easy.

  Further, torque is transmitted between the output wheel 23 and the output shaft 21 in a state where the curved surface 50 e of the cam 50 is separated from the inner peripheral surface 37 of the ring 36. That is, sliding between the inner peripheral surface 37 of the ring 36 and the cam 50 can be prevented. For this reason, when transmitting torque from the output wheel 23 to the output shaft 21, power loss can be suppressed.

  When torque is transmitted between the output wheel 23 and the output shaft 21, one cam 50 is supported by one set of second engaging convex portions 54, and the postures of the three cams 50 are respectively Retained. Therefore, the cam 50 does not swing around the pin 51, and it is possible to prevent the convex portion 50c from colliding with the locking claw 32 and generating abnormal noise.

  The torque threshold in the second embodiment is an artificially determined value, and the torque threshold can be arbitrarily changed by changing the rigidity of the elastic member 49. In the second embodiment, since a metal spring is used as the elastic member 49, the torque threshold is determined by the spring constant. For example, the higher the rigidity of the elastic member 49, the higher the torque threshold.

  Here, the relationship between the configuration in the second embodiment and the configuration of the present invention will be described. The pin 51 corresponds to the support shaft of the present invention, and the cam 50 corresponds to the movable piece of the present invention. The relationship between the other configurations in the second embodiment and the configuration of the present invention is the same as the relationship between the configuration in the first embodiment and the present invention.

(Embodiment 3)
In the clutch device described in Patent Document 1, the braking spring is constantly pressed against the inner peripheral surface of the housing. For this reason, the frictional force generated at the contact portion between the braking spring and the inner peripheral surface of the housing also acts as a braking force when the power of the operating shaft is transmitted to the output shaft via the control plate and the brake cam. Therefore, there is a problem that the power transmission efficiency is reduced when the power of the operation shaft is transmitted to the output shaft. In addition, since a slight play is provided between the engaging projection provided on the brake cam and the engaging hole formed in the control plate, the operating lever is operated even if the operating lever is operated. Therefore, there is a problem that a slight time difference occurs in the timing from when the clutch device is released to when the operation of the seat is started.

  The purpose of the third embodiment of the present invention is to establish a condition for transmitting power from the first power transmission member to the second power transmission member when transmitting power from the first power transmission member to the second power transmission member. It is an object of the present invention to provide a clutch device and a drive device that have no time difference in the timing from when the power transmission is actually started until the power transmission efficiency is reduced, and that can suppress the reduction in power transmission efficiency.

  The third embodiment of the present invention will be described below with reference to FIGS. 2 and 9 to 13. 9 to 13, the same components as those in FIGS. 1 to 5 are denoted by the same reference numerals as those in FIGS. 1 to 5. The output shaft 21 in the second embodiment has a circular outer peripheral shape in a plane perpendicular to the axis B. A locking claw 22 is provided on the outer peripheral surface of the output shaft 21. The locking claw 22 is provided at a location corresponding to the through hole 16 a in the direction along the axis B of the output shaft 21. The locking claw 22 protrudes outward in the radial direction of the output shaft 21. A plurality of, specifically three, locking claws 22 are provided along the circumferential direction with the axis B as the center. The three locking claws 22 are arranged at equal intervals along the circumferential direction around the axis B.

  The locking claw 22 has contact surfaces 22a and 22b at both ends in the circumferential direction around the axis B, respectively. The contact surfaces 22a and 22b are planes parallel to the plane in the direction along the axis. As shown in FIG. 10, the circumferential width between the contact surfaces 22 a and 22 b formed on one locking claw 22 becomes wider toward the inside of the gear case 15 (downward in FIG. 10). . That is, each contact surface 22a, 22b alone is tapered with respect to a straight line C parallel to the axis B. The three locking claws 22 have the same shape such as the amount of protrusion in the radial direction around the axis B and the length in the circumferential direction.

  An output wheel 23 is provided inside the gear case 15. The output wheel 23 is arranged coaxially with the output shaft 21 around the axis B. A shaft hole 23 a is provided at the center of the output wheel 23. The shaft hole 23a has a circular shape centered on the axis B, and the output shaft 21 is inserted into the shaft hole 23a. The output wheel 23 is disposed between the cover 16 and the worm wheel 18 in a direction along the axis B. The output wheel 23 and the output shaft 21 are relatively rotatable. A gear 23 b is formed on the outer peripheral surface of the output wheel 23, and the gear 23 b is engaged with the gear 20. The number of teeth of the gear 23b is larger than the number of teeth of the gear 20. That is, when power is transmitted from the gear 20 to the output wheel 23, the rotational speed of the output wheel 23 is lower than the rotational speed of the gear 20. That is, the two gears 20 and 23 b constitute a speed reduction mechanism 24.

  A pin 25 is fixed to the output wheel 23. A plurality of pins 25, specifically six, are fixed on the same circumference around the axis B. As shown in FIG. 8, the output wheel 23 is provided with six holes 23 c on the same circumference around the axis B. The hole 23c may be formed so as to penetrate the output wheel 23 in the direction along the axis B, or may not penetrate in the direction along the axis B. The six holes 23c are arranged at equal intervals on the circumference centered on the axis B. A pin 25 is inserted and fixed in each hole 23c. The six pins 25 are arranged outside the output shaft 21 in the radial direction about the axis B. Further, the outer peripheral shape of the pin 25 in a plane perpendicular to the axis B is circular. Thus, when the output wheel 23 rotates in a state where the six pins 25 are attached to the output wheel 23, the six pins 25 can revolve around the axis B.

  On the other hand, a bracket 26 is fixed to the cover 16. The bracket 26 has a disk part 26a and a cylinder part 26b formed continuously on the outer periphery of the disk part 26a. A shaft hole 26c is provided through the disk portion 26a, and the output shaft 21 is inserted into the shaft hole 26c. In addition, an inner peripheral surface 26 e as an opposing surface that faces the output shaft 21 is formed in the cylindrical portion 26 b. The output shaft 21 and the bracket 26 are relatively rotatable. Thus, the bracket 26 is formed in an annular shape. The cylindrical portion 26 b is assembled in the through hole 16 a of the cover 16. The cover 16 and the bracket 26 are configured not to rotate relative to each other about the axis B in a state where the cylindrical portion 26b is assembled to the through hole 16a. The outer peripheral surface shape of the cylindrical portion 26b may be circular or non-circular. The shape of the inner peripheral surface of the cylindrical part 26b is circular. In a state where the bracket 26 is fixed to the cover 16, the tip of the cylindrical portion 26 b and the side surface of the output wheel 23 are not in contact with each other.

  Cams 27a and 27b are attached to the six pins 25, respectively. The cams 27 a and 27 b are capable of rotating (rotating) around the axis D of the pin 25 while being attached to the pin 25. The cams 27a and 27b can revolve around the axis B together with the pin 25 when the output wheel 23 rotates. Two locking claws 28 and 29 are provided on the cams 27a and 27b, respectively. The two locking claws 28 and 29 are provided at different positions in the circumferential direction of the pin 25.

  With the cams 27 a and 27 b attached to the pins 25, the locking claw 28 is positioned outside the locking claw 29 in the radial direction of the output wheel 23. Moreover, the location which opposes the inner peripheral surface 26e of the bracket 26 in the latching claw 28 is a curved surface. The curved surface has an arc shape centered on the pin 25. That is, the locking claw 28 is in contact with the inner peripheral surface 26 e of the cylindrical portion 26 b of the bracket 26 on the outer peripheral side of the output wheel 23 with respect to the pin 25, and the locking claw 29 is on the inner peripheral side of the output wheel 23 with respect to the pin 25. It comes into contact with the locking claw 22 of the output shaft 21. The cam 27a and the cam 27b are respectively attached to the pins 25 so as to be alternately arranged in the circumferential direction with the axis B as the center.

  First, in the cam 27a, the locking claw 29 and the contact surface 22a of the locking claw 22 are in contact with each other, and the locking claw 28 is in contact with the inner peripheral surface 26e of the cylindrical portion 26b. That is, the cam 27 a is attached to the pin 25 so that the locking claw 29 is disposed inside the locking claw 28 in the radial direction centered on the axis B. Further, in the locking claw 28, a portion that is diagonally separated from the portion that contacts the contact surface 22 a of the locking claw 29 and the locking claw 22 is an inner peripheral surface 26 e of the cylindrical portion 26 b. The amount of protrusion of the locking claw 22, the length in the circumferential direction of the locking claw 22, the distance between the pins 25 in the circumferential direction, the distance between the locking claws 22 in the circumferential direction, and the like are determined. ing.

  On the other hand, in the cam 27b, the locking claw 29 and the contact surface 22b of the locking claw 22 are in contact, and the locking claw 28 is in contact with the inner peripheral surface 26e of the cylindrical portion 26b. That is, the cam 27 b is attached to the pin 25 so that the locking claw 29 is disposed inside the locking claw 28 in the radial direction centered on the axis B. Further, in the locking claw 28, a portion that is diagonally separated from the portion that contacts the contact surface 22 b of the locking claw 29 and the locking claw 22 is an inner peripheral surface 26 e of the cylindrical portion 26 b. The amount of protrusion of the locking claw 22, the length in the circumferential direction of the locking claw 22, the distance between the pins 25 in the circumferential direction, the distance between the locking claws 22 in the circumferential direction, and the like are determined. ing.

  A coil spring 30 as an elastic member is disposed between the disc portion 26a and the cams 27a and 27b. The coil spring 30 is disposed so as to be wound around the pin 25, and generates a force that constantly pushes the cam 27 a and the cam 27 b toward the output wheel 23. The clutch device 31 of this embodiment is configured by the above-described elements such as the bracket 26, the pin 25, the cams 27a and 27b, the coil spring 30, and the like. That is, the drive device 10 of the present embodiment includes the clutch device 31. The elements such as the output shaft 21, the bracket 26, the pin 25, the cams 27a and 27b, and the coil spring 30 are all made of a metal material such as iron.

  The operation of the driving device 10 of this embodiment will be described. First, the case where the electric motor 11 stops and no external force is applied from the power transmission shaft to the output shaft 21 will be described. The six cams 27 a and 27 b constituting the clutch device 31 are always pushed toward the output wheel 23 by the force of the coil spring 30. Further, the contact surfaces 22a and 22b of the locking claw 22 are tapered.

  For this reason, among the six cams 27 a and 27 b, the locking claws 29 of the three cams 27 a are always kept in contact with the contact surface 22 a of the locking claw 22. Further, the locking claws 28 of the three cams 27a are always kept in contact with the inner peripheral surface 26e of the cylindrical portion 26b. For this reason, the three cams 27a are stopped without rotating around the pin 25. On the other hand, the locking claws 29 of the remaining three cams 27 b are always in contact with the contact surface 22 b of the locking claw 22. Further, the locking claws 28 of the three cams 27b are always kept in contact with the inner peripheral surface 26e of the cylindrical portion 26b. For this reason, the three cams 27b are stopped without rotating around the pin 25.

  Next, a case where an external force (load) is applied from the power transmission shaft to the output shaft 21 while the electric motor 11 is stopped will be described. For example, when an external force is applied to the output shaft 21 and a clockwise torque about the axis B is generated in the output shaft 21, the contact surfaces 22b of the three locking claws 22 of the output shaft are connected to the three cams 27b. A counterclockwise force about the pin 25 is applied to each of the three cams 27b by being pressed against the locking claws 29, respectively. Then, the force which presses the latching claw 28 of the three cams 27b against the inner peripheral surface 26e of the cylinder part 26b increases. That is, the locking claws 28 of the three cams 27b bite into the inner peripheral surface 26e. The three cams 27b are prevented from rotating counterclockwise about the pin 25 by the frictional force of the contact surface between the locking claws 28 of the three cams 27b and the inner peripheral surface 26e. . For this reason, the output shaft 21 does not rotate clockwise around the axis B. Therefore, the torque transmitted from the power transmission shaft to the output shaft 21 is not transmitted to the output wheel 23.

  On the other hand, when counterclockwise torque about the axis B is applied to the output shaft 21 while the electric motor 11 is stopped, the contact surfaces 22a of the three locking claws 22 of the output shaft 21 are applied. Are pressed against the locking claws 29 of the three cams 27a, and a clockwise force is applied to the three cams 27a around the pin 25. Then, the force which presses the latching claw 28 of the three cams 27a against the inner peripheral surface 26e of the cylinder part 26b increases. That is, the locking claws 28 of the three cams 27a bite into the inner peripheral surface 26e. The three cams 27a are prevented from rotating clockwise around the pin 25 by the frictional force between the locking claws 28 of the three cams 27a and the inner peripheral surface 26e. For this reason, the output shaft 21 does not rotate counterclockwise about the axis B.

  Therefore, the torque transmitted from the power transmission shaft to the output shaft 21 is not transmitted to the output wheel 23. As described above, the drive device 10 according to the present embodiment can prevent the external force from being transmitted to the electric motor 11 even if an external force is applied to the output shaft 21 while the electric motor 11 is stopped. That is, the clutch device 31 is in a state where the power of the output shaft 21 is not transmitted to the output wheel 23.

  Next, the electric motor 11 is stopped and the output shaft 21 is stopped, or the torque is transmitted from the power transmission shaft to the output shaft 21 and the output shaft 21 is stopped. The operation when switching to a state in which the power of the motor 11 is transmitted to the output shaft 21 will be described. In the electric motor 11, when electric power is supplied to the electromagnetic coil and a rotating magnetic field is formed, the armature shaft 14 rotates in one direction, for example, the positive direction by the rotating magnetic field. The torque of the armature shaft 14 is transmitted to the gear 20 via the worm 14 a and the worm wheel 18. Then, torque in a predetermined direction, for example, clockwise in FIGS. 9 and 12 is applied to the output wheel 23. This torque is a force in a direction to revolve the six cams 27a and 27b in a clockwise direction on the circumference around the axis B.

  Then, out of the six cams 27a and 27b, the three cams 27a have a contact portion between the locking claw 28 and the inner peripheral surface 26e of the cylindrical portion 26b, and a contact surface between the locking claw 29 and the locking claw 22. The circumferential force applied to the contact portion with 22a increases. Here, the locking claw 28 of the three cams 27a and the inner peripheral surface 26e are kept in contact with each other by frictional force, while the locking claw 29 of the three cams 27a, the locking claw 22, The contact state is maintained by the engaging force. For this reason, the engaging force between the locking claw 29 and the locking claw 22 of the three cams 27a is stronger than the frictional force between the locking claw 28 of the three cams 27a and the inner peripheral surface 26e. Therefore, the clutch device 31 receives the reaction force at the contact portion between the locking claw 28 of the three cams 27a and the inner peripheral surface 26e, and transmits the power of the output wheel 23 to the locking claw of the three cams 27a. 29 is transmitted to the output shaft 21 from a contact portion between the engaging claw 22 and the engaging claw 22. That is, while the locking claws 28 of the three cams 27a serving as fulcrums are in contact with the inner peripheral surface 26e, they move in the circumferential direction while sliding along the inner peripheral surface 26e. Is transmitted to the output shaft 21. In this way, the output shaft 21 rotates clockwise about the axis B.

  On the other hand, when a force is applied to the remaining three cams 27b so as to revolve clockwise in the circumferential direction about the axis B, the three cams 27b include the locking claws 29 and the locking claws 22. The contact surface 22b of the cylindrical portion 26b is in contact with the inner peripheral surface 26e of the cylindrical portion 26b while rotating in a clockwise direction around the axis B. That is, the three cams 27b revolve clockwise in the circumferential direction about the axis B, and at the same time, the output shaft 21 rotates clockwise in the circumferential direction about the axis B. That is, the revolution speed of the three cams 27b matches the rotation speed of the output shaft 21. In other words, the angular velocity when the three cams 27b revolve and the angular velocity of the output shaft 21 are the same. This prevents the three cams 27b from rotating counterclockwise about the pin 25. Accordingly, when the output shaft 21 rotates with the torque transmitted from the electric motor 11 to the output wheel 23, the friction of the contact portion between the locking claws 28 of the three cams 27b and the inner peripheral surface 26e of the cylindrical portion 26b. Power does not increase.

  Next, the armature shaft 14 is stopped and the output shaft 21 is stopped, or the torque is transmitted from the power transmission shaft to the output shaft 21 and the output shaft 21 is stopped. The operation when the motor 11 is driven and the armature shaft 14 is switched to the state of rotating in the reverse direction will be described. When the armature shaft 14 rotates in the reverse direction, a counterclockwise torque is transmitted to the output wheel 23 in FIGS. 9 and 12. That is, power is generated by the output wheel 23.

  Then, out of the six cams 27a and 27b, the three cams 27b have contact portions between the locking claws 28 and the inner peripheral surface 26e of the cylindrical portion 26b, and contact surfaces between the locking claws 29 and the locking claws 22. The circumferential force applied to the contact portion with 22b increases. Here, the engaging claw 28 of the three cams 27b and the inner peripheral surface 26e are kept in contact with each other by a frictional force. On the other hand, the locking claw 29 and the locking claw 22 of the three cams 27b are kept in contact with each other by the engagement force. For this reason, the engaging force between the locking claw 29 of the three cams 27b and the contact surface 22b of the locking claw 22 is greater than the frictional force between the locking claw 28 of the three cams 27b and the inner peripheral surface 26e. Is stronger.

  Therefore, the clutch device 31 receives the reaction force at the contact portion between the locking claw 28 of the three cams 27b and the inner peripheral surface 26e, and transmits the power of the output wheel 23 to the locking claw of the three cams 27b. 29 is transmitted to the output shaft 21 from a contact portion between the engaging claw 22 and the engaging claw 22. That is, in a state in which the locking claws 28 of the three cams 27b serving as fulcrums are in contact with the inner peripheral surface 26e, the locking claw 28 moves while sliding in the circumferential direction, whereby the power of the output wheel 23 is output to the output shaft. 21 is transmitted. In this way, the output shaft 21 rotates clockwise about the axis B.

  On the other hand, when a force is applied to the three cams 27a so as to revolve counterclockwise in the circumferential direction around the axis B in FIGS. And the contact surface 22a of the locking claw 22, and the locking claw 28 and the inner peripheral surface 26e of the cylindrical portion 26b are in contact with each other in the counterclockwise direction around the axis B. Revolve to. The three cams 27a revolve counterclockwise in the circumferential direction around the axis B, and at the same time, the output shaft 21 rotates counterclockwise in the circumferential direction around the axis B. That is, the revolution speed of the three cams 27a matches the rotation speed of the output shaft 21. In other words, the angular velocity when the three cams 27a revolve and the angular velocity of the output shaft 21 are the same. This prevents the three cams 27a from rotating counterclockwise around the pin 25. Therefore, when the output shaft 21 rotates with the torque transmitted from the electric motor 11 to the output wheel 23, the friction at the contact portion between the locking claws 28 of the three cams 27a and the inner peripheral surface 26e of the cylindrical portion 26b. Power does not increase.

The principle of generation of the braking force in the clutch device 31 is as follows. The distance between the center position of the pin 25 and the center position in the circumferential direction of the curved surface of the locking claw 28 of the cam 27a or the cam 27b is based on the distance between the center position of the pin 25 and the inner peripheral surface 26e of the cylindrical portion 26b. Is set too small. The distance between the center position of the pin 25 and the end portion in the circumferential direction of the curved surface of the locking claw 28 of the cam 27a or the cam 27b is the distance between the center position of the pin 25 and the inner peripheral surface 26e of the cylindrical portion 26b. It is set larger than the distance. Therefore, when the cam 27a or the cam 27b is held at the neutral position, a gap is formed between the curved surface of the locking claw 28 in the cam 27a or the cam 27b and the inner peripheral surface 26e of the cylindrical portion 26b. . On the other hand, when the cam 27a or the cam 27b tilts about the pin 25 from the neutral position, the curved surface of the locking claw 28 of the cam 27a or the cam 27b comes into sliding contact with the inner peripheral surface 26e of the cylindrical portion 26b, and the control As described above, the clutch device 31 of the present embodiment automatically has a state where the power of the output shaft 21 is not transmitted to the output wheel 23 and a state where the power of the output wheel 23 is transmitted to the output shaft 21. Switch. In the clutch device 31, the six cams 27a and 27b are always pushed in the direction along the axis B by the force of the coil spring 30, and the locking claws 29 of the six cams 27a and 27b are locked. The nail 22 is always in contact. That is, there is no play between the locking claw 29 and the locking claw 22. At the same time, the locking claws 29 of the six cams 27a and 27b are always in contact with the inner peripheral surface 26e of the cylindrical portion 26b.

  Therefore, the electric motor 11 is stopped and no torque is transmitted from the power transmission shaft to the output shaft 21, or the electric motor 11 is stopped and the torque is transmitted from the operation transmission shaft to the output shaft 21. When the torque of the electric motor 11 is switched to the state where the torque of the electric motor 11 is transmitted to the output wheel 23, it is possible to avoid a state where the power is not transmitted transiently. That is, it is possible to prevent the occurrence of “torque loss” in which torque is not transmitted to the output shaft 21 even though torque is transmitted from the electric motor 11 to the output wheel 23. That is, it is possible to prevent a time difference from occurring in the timing until the power is actually transmitted from the output wheel 23 to the output shaft 21 after the condition for transmitting the power from the output wheel 23 to the output shaft 21 is established. The condition for transmitting power from the output wheel 23 to the output shaft 21 is established, for example, when a switch for operating the operating member is operated.

  Further, the clutch device 31 of the present embodiment applies a force in the direction along the axis B to the cams 27a and 27b by the force of the coil spring 30, so that the locking claw 29 is always in contact with the contact surfaces 22a and 22b. ing. For this reason, the force applied to the cams 27a and 27b from the coil spring 30 does not increase the frictional force at the contact portion between the locking claw 28 of the cams 27a and 27b and the inner peripheral surface 26e. Therefore, when the power of the electric motor 11 is transmitted from the output wheel 23 to the output shaft 21, it is possible to suppress a decrease in power transmission efficiency.

  Here, the correspondence between the configuration described in Embodiment 3 and the configuration of the present invention will be described. The output wheel 23 corresponds to the first power transmission member of the present invention, and the output shaft 21 of the present invention. It corresponds to the second power transmission member, the axis B corresponds to the first axis of the present invention, the axis D corresponds to the second axis of the present invention, and the coil spring 30 corresponds to the force applying member of the present invention. The bracket 26 corresponds to the fixing member of the present invention, the inner peripheral surface 26e corresponds to the facing surface of the present invention, the cams 27a and 27b correspond to the movable piece of the present invention, and the locking claw 22 The locking claw 29 corresponds to the first contact portion of the present invention, and the locking claw 28 corresponds to the second contact portion of the present invention.

  It goes without saying that the present invention is not limited to the first to third embodiments, and various modifications can be made without departing from the scope of the invention. For example, as the elastic member in the first embodiment, a compression coil spring or a rubber-like elastic body can be used. The compression coil spring is arranged in a direction that expands and contracts in the circumferential direction about the axis. Furthermore, when using a compression coil spring, it is also possible to provide a guide portion for guiding expansion and contraction of the compression coil spring on the end face of the output wheel. Moreover, the power transmission device in the first and second embodiments may be provided with four or more pins and cams. Further, although the ring 36 is provided separately from the cover 16 and the bracket 26, the ring 36 may be integrally formed with the cover 16 or the bracket 26.

  In the clutch device 31 according to the third embodiment, the number of pins attached to the output wheel 23 and the number of cams attached to the pins are an even number and the same number. That is, the number of pins and cams in this embodiment may be four or eight.

  Further, the clutch device according to the third embodiment includes a structure in which the pin and the cover are not in contact with each other. With this structure, when gear power is transmitted to the output shaft via the pin and cam, it is possible to prevent power loss due to frictional resistance between the pin and the cover. In the clutch device according to the third embodiment, as shown in FIG. 13, an outward flange 25a is provided on the pin 25, and a coil spring 30 (elastic member) is interposed between the outward flange 25a and the cams 27a and 27b. Including the structure to be made. In this structure, the reaction force when the coil spring 30 pushes the cams 27 a and 27 b is received by the outward flange 25 a, and the coil spring 30 does not contact the bracket 26. Therefore, it is possible to prevent power loss due to the frictional resistance between the coil spring 30 and the bracket 26. If the outward flange 25 a is provided, the elastic member can be a disc spring instead of the coil spring 30.

  Moreover, as shown in FIG. 14, the taper inclination directions of the contact surfaces 22a and 22b provided on the locking claws 22 in the direction of the axis B may be reversed. In this case, a coil spring 30 is provided between the cams 27 a and 27 b and the output wheel 23. Furthermore, the force applying member in the present invention can use a rubber-like elastic body instead of the spring. The drive device of the present invention includes a structure in which the power of the electric motor is transmitted to the output shaft via the output wheel, and a structure in which the power of the electric motor is transmitted to the output wheel via the output shaft. The drive device of the present invention includes a mechanism for operating a seat back provided in a vehicle, a seat cushion, glass provided in a door, and the like by the power of an electric motor.

  The power transmission device and the clutch device of the present invention include a configuration in which the first power transmission member is operated manually. The power transmission device and the clutch device having this configuration have operation members such as an operation lever and an operation knob provided on the vehicle. The operation lever can be reciprocated within a predetermined angle range around the support shaft. The operation knob can be rotated about the rotation axis. The power transmission device and the clutch device having this configuration are configured such that the operating force applied to the operation member is converted into the power of the first power transmission member. In the power transmission device and the clutch device having this configuration, when the operation member is operated, a condition for transmitting power from the first power transmission member to the second power transmission member is established. The power transmission device and the clutch device having this configuration can prevent a time difference from occurring in the timing from when the operation member is operated until the power of the first power transmission member is transmitted to the second power transmission member.

  The power transmission device, the clutch device, and the drive device of the present invention can be used as a mechanism for operating an operation member provided in a vehicle, for example, a seat back, a seat cushion, a glass provided in a door, and the like. .

Claims (7)

A first power transmission member and a second power transmission member rotatable about an axis;
A plurality of support shafts provided in the first power transmission member along a circumferential direction around the axis;
A plurality of movable pieces that are rotatably supported by the plurality of support shafts and have curved surfaces that gradually increase as the distance from the support shaft reaches an end;
A plurality of locking claws provided on the second power transmission member and engaged with the plurality of movable pieces,
A fixing member provided to be fixed outside the plurality of movable pieces in a radial direction centered on the axis;
An elastic member having a sliding portion that slides with the fixed member, and a movable piece holding portion that holds the movable piece;
Have
A power transmission device in which the curved surface of the movable piece is held by the movable piece holding portion at a position where it does not contact the fixed member;
When the torque transmitted between the first power transmission member and the second power transmission member exceeds a threshold value, the movable piece is centered on the support shaft against the movable piece holding portion of the elastic member. A power transmission device, wherein the power transmission device rotates and the curved surface comes into contact with the fixing member to generate a braking force, and torque is not transmitted between the first power transmission member and the second power transmission member. The power transmission device according to claim 1,
When the torque transmitted between the first power transmission member and the second power transmission member is equal to or less than a threshold value, the first power is generated by the engagement force between the plurality of movable pieces and the plurality of locking claws. Torque is transmitted between the transmission member and the second power transmission member. The power transmission device according to claim 1,
The elastic member has a plurality of engaging portions that respectively engage with the plurality of locking claws,
When the torque transmitted between the first power transmission member and the second power transmission member is a threshold value or less, the engagement force between the plurality of engagement portions and the plurality of locking claws, and the plurality Torque is transmitted between the first power transmission member and the second power transmission member by an engagement force between the movable piece and the plurality of movable piece holding portions. A drive device in which the power of the electric motor is transmitted to the second power transmission member via the first power transmission member,
4. A driving device comprising: the power transmission device according to claim 1 provided between the first power transmission member and the second power transmission member. 5. A first power transmission member and a second power transmission member that are rotatable about the first axis are provided, and power can be transmitted between the first power transmission member and the second power transmission member. A clutch device that switches between a normal state and a state where power cannot be transmitted,
An annular fixing member having a facing surface facing the second power transmission member in a radial direction about the first axis;
A protrusion provided on the second power transmission member and protruding toward the fixing member in a radial direction centered on the first axis;
The second power transmission member is disposed between the second power transmission member and the fixing member in a radial direction about the first axis, and the second power transmission member is centered on a second axis parallel to the first axis. A movable piece attached rotatably,
A first contact portion provided on the movable piece and in contact with the protruding portion;
A second contact portion provided on the movable piece and in contact with the fixed member;
A force in a direction along the second axis is constantly applied to the movable piece, the first contact portion comes into contact with the projecting portion, and the second contact portion comes into contact with the inner peripheral surface of the fixed member. A clutch device comprising a force applying member for maintaining the state. A drive device in which the power of the electric motor is transmitted to the second power transmission member via the first power transmission member,
A clutch device is provided that switches between a state in which power transmission can be performed and a state in which power transmission cannot be performed between the first power transmission member and the second power transmission member. A drive apparatus having the structure described in item 5. A first power transmission member and a second power transmission member that are rotatable about the first axis are provided, and power can be transmitted between the first power transmission member and the second power transmission member. A clutch device that switches between a normal state and a state where power cannot be transmitted,
An annular fixing member having a facing surface facing the second power transmission member in a radial direction about the first axis;
A protrusion provided on the second power transmission member and protruding toward the fixing member in a radial direction centered on the first axis;
The second power transmission member is disposed between the second power transmission member and the fixing member in a radial direction about the first axis, and the second power transmission member is centered on a second axis parallel to the first axis. A movable piece attached rotatably,
A first contact portion provided on the movable piece and in contact with the protruding portion;
A second contact portion provided on the movable piece and in contact with the fixed member;
A clutch device comprising:

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