JP2011112072A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems accompanying overload and those on accuracy without causing a situation of manufacturing cost increase and enlargement of an applicable object. <P>SOLUTION: A power transmission device includes a first ring gear 30 and a second ring gear 40 whose respective inner circumferential gear parts 30a, 40a engage with planetary gears 20 and a brake means, which gives braking torque of preset magnitude using the first ring gear 30 as a stopping element. In this device, a sun gear 10 is used as an input element, while the second ring gear 40 is used as an output element. The brake means restrains the relative rotation of a contacting member to the first ring gear 30 by making it engage with the first ring gear 30 via inclined surfaces 33a, 61a. On the other hand, when rotating torque exceeding the braking torque is applied to the first ring gear 30, relative rotation to the stopping element is permitted because inclining action causes the contacting member to move so as to be relatively separated from the first ring gear. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a power transmission device, and more particularly to a power transmission device having a torque limiter function.

  An example of this type of power transmission device is described in Patent Document 1. In the power transmission device described in Patent Document 1, the sun gear of the planetary gear mechanism is configured as an input element, and the planetary carrier is configured as an output element. A desired brake torque is applied to the ring gear by pressing the friction member in the axial direction.

  In this power transmission device, when the sun gear is rotated, the rotation of the ring gear is restricted by the friction member, so that the planetary carrier can revolve and transmit power. If the rotational load torque of the planetary carrier exceeds the brake torque from this state, it can overcome the brake torque and the ring gear can rotate to release the drive torque of the drive source, possibly causing damage such as damage to the planetary gear mechanism. Absent.

JP 2007-170547 A

  By the way, in the power transmission device described in Patent Document 1, the pressing force of the friction member against the ring gear is the only configuration for restricting the rotation of the ring gear. That is, if the pressing force of the friction member against the ring gear is increased, the rotation of the ring gear can be more reliably regulated. However, in order to increase the pressing force of the friction member against the ring gear, it is necessary to apply a pressing member having a large set load. When a pressing member having a large set load is applied, the rigidity of each part must be increased corresponding to the set load, which causes an increase in the size of the apparatus and an increase in manufacturing cost. Moreover, even if the load on the pressing member is set large, it is difficult to prevent micro slip of the ring gear. Therefore, for example, when the power transmission device is applied to the positioning mechanism, the accuracy may be affected.

  In view of the above circumstances, the present invention provides a power transmission device capable of solving problems associated with overload and problems in accuracy without causing an increase in manufacturing cost or an increase in the size of an application target. For the purpose.

  In order to achieve the above object, a power transmission device according to the present invention meshes with a first gear member rotatably arranged around its own axis and the first gear member, and around its own axis. An intermediate gear member supported by the carrier so as to be rotatable and revolved around the axis of the first gear member, and an inner peripheral gear portion on the inner peripheral portion, the axis of the first gear member One of the second gear member, the first gear member, the second gear member, and the carrier that is disposed so as to be rotatable around and that meshes with the intermediate gear member via an inner peripheral gear portion. And a brake means for applying a brake torque having a preset magnitude with the brake element as a stop element, and using one of the remaining two of the brake means not applying the brake torque as an input element and the other as an output element A transmission device comprising the blur The key means regulates the relative rotation with the stop element by engaging with the stop element via an inclined surface, while the rotating action is applied to the stop element when a rotational torque exceeding the brake torque is applied. The relative rotation with the stop element is allowed by relatively moving away from each other.

  The power transmission device according to the present invention includes a first gear member disposed rotatably about its own axis, and meshes with the first gear member, is rotatable about its own axis, and An intermediate gear member supported to be revolved around the axis of the first gear member, an inner peripheral gear part on the inner peripheral part, and arranged rotatably around the axis of the first gear member; A second gear member meshing with the intermediate gear member via an inner peripheral gear portion, and an inner peripheral gear portion having a number of teeth different from the inner peripheral gear portion of the second gear member on the inner peripheral portion, A third gear member that is rotatably arranged about the axis of the first gear member and meshes with the intermediate gear member via an inner peripheral gear portion, and the second gear member is set in advance as a stop element. Brake means for applying a brake torque having a magnitude, the first gear member as an input element, and In the power transmission device using the third gear member as an output element, the brake means engages with the second gear member via an inclined surface to restrict relative rotation with the second gear member. On the other hand, when a rotational torque exceeding the brake torque is applied to the second gear member, relative rotation with the second gear member is allowed by moving relatively apart by an inclination action. .

  In the power transmission device described above, the brake unit may include an inclined surface formed on the stop element, an abutting member having an inclined surface that contacts the inclined surface of the stop element, and the contact And a pressing member that presses the inclined surface of the member against the inclined surface of the stop element.

  Further, the present invention is characterized in that, in the power transmission device described above, the brake means includes an inclined surface formed on the stop element and a pressing member that presses the stop element via the inclined surface. To do.

  According to the present invention, in the power transmission device described above, the second gear member has an outer peripheral gear portion on an outer peripheral portion, and the brake means has an outer peripheral gear portion on the outer peripheral portion. A fourth gear member disposed rotatably around its own axis with the gear portion engaged with the outer peripheral gear portion of the second gear member; and the fourth gear member rotatable in the axial direction A brake shaft member that is slidably supported along the shaft, a contact portion provided in a state in which movement in the axial direction is restricted at the distal end portion of the brake shaft member, and a pressure that presses the fourth gear member against the contact portion And the inclined surface is provided between the fourth gear member and the contact portion.

  According to the present invention, when the rotational load torque acting on the output element is lower than the brake torque, when the input element is driven, the output element is rotated because the rotation of the stop element is restricted. On the other hand, when the rotational load torque acting on the output element exceeds the brake torque, the rotation of the output element is restricted even when the input element is driven, and the stop element is rotated by overcoming the brake torque. . Thereby, it becomes possible to cut off the power transmission to the output element without requiring an actuator or a controller for controlling the driving of the actuator separately. In addition, the relative rotation with the stop element is restricted by engaging the stop element via the inclined surface as a brake means, and when the rotation torque exceeding the brake torque is applied to the stop element, Since it is used to allow relative rotation with the stop element by moving away from each other, it is possible to reliably prevent the stop element from rotating when the input element is not rotating. It can be prevented from rotating.

1-1 is a partially cutaway side view of a power transmission apparatus according to Embodiment 1 of the present invention. 1-2 is a partially cutaway side view of the power transmission device according to Embodiment 1 of the present invention, and shows a state in which a rotational torque exceeding the brake torque is applied. FIG. 2 is a cross-sectional side view of the power transmission device shown in FIG. 1-1. 3 is a cross-sectional plan view of the power transmission device shown in FIG. 1-1. FIG. 4 is a partially cutaway side view of the power transmission apparatus according to Embodiment 2 of the present invention. FIG. 5 is a cross-sectional side view of the power transmission device shown in FIG. 4. FIG. 6 is a cross-sectional side view of the power transmission device according to the third embodiment of the present invention. 7 is a cross-sectional plan view of the power transmission device shown in FIG. FIG. 8A is a side view of the main part of the power transmission device shown in FIG. 6. FIG. 8-2 is a side view of the main part of the power transmission device shown in FIG. 6 and shows a state in which a rotational torque exceeding the brake torque is applied.

  Exemplary embodiments of a power transmission device according to the present invention will be described below in detail with reference to the accompanying drawings.

(Embodiment 1)
FIGS. 1-1 to 3 show a power transmission apparatus according to Embodiment 1 of the present invention. The power transmission device illustrated here is applied to an actuator unit using the drive motor 1 as a drive source, and includes a sun gear (first gear member) 10 on a drive shaft 1 a of the drive motor 1. The sun gear 10 is a spur gear having an outer peripheral gear portion 10a on the outer peripheral portion, and is fixed to the drive shaft 1a of the drive motor 1 in a state where the shaft centers thereof are matched. The sun gear 10 has a mysterious gear mechanism formed by meshing a first ring gear (second gear member) 30 and a second ring gear (third gear member) 40 via a plurality of planetary gears (intermediate gear members) 20. It is.

  The planetary gear 20 is a spur gear having an outer peripheral gear portion 20 a on the outer peripheral portion and an integral shaft. Three planetary gears 20 are arranged around the sun gear 10. These planetary gears 20 are supported by a pair of upper and lower planetary carriers 21 in such a manner that their respective axes are parallel to the axis of the sun gear 10 and are equally spaced from each other. In FIG. 1, the planetary carrier 21 positioned below has a sliding hole 21 a formed in the bottom wall. This sliding hole 21a rotates the planetary carrier 21 around the axis of the drive shaft 1a with respect to the main body case 1b by fitting the protrusion 1c provided on the main body case 1b of the drive motor 1 to be slidable. Support as possible. Each planetary gear 20 supported by the planetary carrier 21 meshes with the sun gear 10 via the outer peripheral gear portion 20a, and each of the planetary gears 20 can rotate around its own axis and can be rotated by the planetary carrier 21. It can revolve around its axis.

  The first ring gear 30 has an annular shape and has an inner peripheral gear portion 30a on the inner peripheral surface thereof. The first ring gear 30 can rotate about the axis of the drive shaft 1a on the upper surface of the fixed body 2 attached to the main body case 1b.

  In the first ring gear 30, a peripheral wall 31 is formed on the outer peripheral portion of the opening end face, and a flange 32 is formed at a portion that is further outer peripheral than the peripheral wall 31. The peripheral wall 31 is a ring-shaped portion that protrudes from the outer peripheral portion of the opening end surface of the first ring gear 30, and is configured to have the same axial center as the first ring gear 30. The flange 32 is a portion that protrudes radially outward from the outer periphery of the base end portion of the first ring gear 30, and has convex portions 33 at a plurality of locations on the upper surface thereof. As shown in FIG. 1-2, the convex portion 33 is formed in a substantially trapezoidal shape such that the width gradually decreases as it protrudes, and has inclined surfaces 33a on both sides.

  As shown in FIGS. 1-1 to 3, the second ring gear 40 has a bottomed cylindrical shape, and has an inner peripheral gear portion 40 a on its inner peripheral surface, and its own shaft on the outer surface of the bottom wall. An integral output shaft portion 41 is provided at a central part. When compared with the above-described first ring gear 30, the second ring gear 40 has an outer diameter that is slightly smaller, and an inner circumference in which the number of teeth of the inner circumferential gear portion 40 a is formed on the inner circumferential surface of the first ring gear 30. The gear part 30a is configured to be different from each other. The second ring gear 40 accommodates the three planetary gears 20 including the planetary carrier 21 and the sun gear 10 between the second ring gear 40 and the first ring gear 30 by bringing the opening end surface into contact with the opening end surface of the first ring gear 30. .

  On the other hand, the power transmission device is provided with a cover member 50 at a position covering the second ring gear 40. The cover member 50 has a bottomed cylindrical shape and has a through hole 50a at the center of the bottom wall. The cover member 50 is driven in a state where the output shaft portion 41 of the second ring gear 40 is passed through the through hole 50a. It is attached to the main body case 1 b of the motor 1.

  An abutting member 60 and a pressing spring (pressing member) 70 are arranged inside the cover member 50. The contact member 60 has an annular shape having an inner diameter larger than that of the peripheral wall 31 of the first ring gear 30, and is arranged on the outer peripheral portion of the peripheral wall 31 in a state of being rotatable around the axis of the drive shaft 1a. It is set up. A plurality of concave portions 61 are provided on the end surface of the contact member 60 facing the flange 32 of the first ring gear 30. The concave portion 61 is formed in a shape and size that can fit the convex portion 33 of the first ring gear 30. The concave portion 61 has an inclined surface 61 a that faces the inclined surface 33 a and is provided on the first ring gear 30. The number and position are adjusted so that all of the plurality of convex portions 33 can be fitted simultaneously. The contact member 60 is provided with an engagement protrusion 62 that fits into an engagement groove 52 provided on the inner peripheral surface of the cover member 50. The engaging protrusion 62 engages with the engaging groove 52 of the cover member 50 to restrict relative rotation with the cover member 50, while being along the axial direction of the drive shaft 1 a with respect to the cover member 50. It functions to allow movement. The pressing spring 70 is a coil spring interposed between the cover member 50 and the contact member 60. The pressing spring 70 functions to apply a preset brake torque to the first ring gear 30 by constantly pressing the first ring gear 30 against the upper surface of the fixed body 2 via the contact member 60.

  Here, in the power transmission device, the convex portion 33 formed on the first ring gear 30 and the concave portion 61 formed on the contact member 60 are fitted as described above. On the other hand, in order to relatively rotate the first ring gear 30, it is necessary to release the fitting state between the convex portion 33 and the concave portion 61. That is, when the rotational force from the drive motor 1 acts on the first ring gear 30 via the sun gear 10 and the planetary gear 20, the pressing spring 70 is caused by the action of the inclined surfaces 33 a and 61 a that are in contact with each other at the convex portion 33 and the concave portion 61. The contact member 60 moves away from the first ring gear 30 against the pressing force, and the fitting state between the convex portion 33 and the concave portion 61 is released. Therefore, the brake torque by the pressing spring 70 is equivalent to the rotational torque necessary to release the fitting state between the convex portion 33 and the concave portion 61.

  In the power transmission device configured as described above, when the drive motor 1 is driven, the sun gear 10 rotates in one direction around its own axis. At this time, when the rotational load torque of the output shaft portion 41 is smaller than the brake torque, the relative rotation of the first ring gear 30 with respect to the contact member 60 is prevented. Accordingly, the planetary gear 20 revolves while rotating due to the rotation of the sun gear 10, and the second ring gear 40 rotates due to the revolution of the planetary gear 20, and the power of the drive motor 1 is output to the outside via the output shaft portion 41. be able to.

  In this case, as described above, the contact member 60 and the first ring gear 30 are in a state in which relative rotation is prevented by the convex portion 33 and the concave portion 61 being fitted to each other. Accordingly, micro slip does not occur between the contact member 60 and the first ring gear 30 unless the fitting state of the convex portion 33 and the concave portion 61 is released. In addition, the set load of the pressing spring 70 may be of a level that prevents the convex portion 33 from deviating from the concave portion 61, and only by the frictional force between the contact member 60 and the first ring gear 30. It is possible to set the first ring gear 30 to be smaller than that which restricts the rotation of the first ring gear 30. Thereby, it is not necessary to set the rigidity of each part of the power transmission device to be large, and it becomes possible to suppress the increase in the size of the device and the increase in the manufacturing cost.

  On the other hand, when the rotational load torque of the output shaft portion 41 exceeds the brake torque in the above-described state, the action of the inclined surfaces 33 a and 61 a that are in contact with each other between the convex portion 33 and the concave portion 61 causes the pressing spring 70 to move. The fitting state of the convex portion 33 and the concave portion 61 is released against the pressing force, the first ring member rotates with respect to the contact member 60, and the power transmission to the second ring gear 40 is transmitted. Be cut off.

  When the rotational load torque of the output shaft portion 41 again falls below the brake torque from the above state, the fitting state between the convex portion 33 and the concave portion 61 is continued, and the second ring gear 40 is rotated by the rotation of the sun gear 10. And the power of the drive motor 1 can be output to the outside via the output shaft portion 41.

  Thus, according to the power transmission device, power transmission to the output shaft portion 41 can be interrupted without requiring an actuator or a controller for controlling the driving of the actuator separately. In addition, as described above, when the convex portion 33 and the concave portion 61 are in the fitted state, microslip cannot occur, so that the set load of the pressing spring 70 is not increased without increasing the setting load. A situation in which the one ring gear 30 rotates can be reliably prevented. Thereby, for example, when the power transmission device is applied to the positioning mechanism, it is possible to ensure high accuracy.

(Embodiment 2)
4 and 5 show a power transmission apparatus according to Embodiment 2 of the present invention. The power transmission device illustrated here is applied to an actuator unit using the drive motor 1 as a drive source, as in the first embodiment, and is different from the first embodiment only in the configuration of the brake means.

  That is, in the power transmission device of the second embodiment, a wave washer (pressing member) 80 is interposed between the first ring gear (second gear member) 30 and the fixed body 2, and the pressing force of the wave washer 80 is used. The first ring gear 30 is brought into contact with the step portion 53 of the cover member 50. As shown in FIG. 5, in the wave washer 80, a pressing portion 80b is bent with respect to a reference flat plate-like base portion 80a, and hemispherical curved protruding portions 80c are formed to protrude at a plurality of locations of the pressing portion 80b. The pressing member is attached to the fixed body 2 in a state in which relative rotation with respect to the fixed body 2 is prevented. A concave portion 35 that fits into the curved convex portion 80 c of the wave washer 80 is formed on the end surface of the first ring gear 30 that faces the fixed body 2. The number and position of the concave portions 35 of the first ring gear 30 are adjusted so that all the curved convex portions 80c of the wave washer 80 can be fitted simultaneously.

  The wave washer 80 according to the second embodiment functions to apply a preset brake torque to the first ring gear 30, as with the pressing spring 70 according to the first embodiment. Here, in the power transmission device, the concave portion 35 formed in the first ring gear 30 and the curved convex portion 80 c formed in the wave washer 80 are fitted, and the first ring gear 30 is attached to the fixed body 2. In order to perform the relative rotation, it is necessary to release the fitting state between the concave portion 35 and the curved convex portion 80c. That is, when the rotational force from the drive motor 1 acts on the first ring gear 30 via the sun gear (first gear member) 10 and the planetary gear (intermediate gear member) 20, the curved convex portions 80c and the concave portions 35 are curved to contact each other. By the action of the inclined surfaces 80d and 35a, the curved convex portion 80c is elastically deformed so as to deviate from the concave portion 35 against the pressing force of the wave washer 80, and the fitting state between the curved convex portion 80c and the concave portion 35 is released. Will be. Therefore, the brake torque by the wave washer 80 is equivalent to the rotational torque necessary to release the fitting state between the curved convex portion 80c and the concave portion 35. Since other configurations are the same as those in the first embodiment, the same reference numerals are given and detailed descriptions thereof are omitted.

  In the power transmission device configured as described above, when the drive motor 1 is driven, the sun gear 10 rotates in one direction around its own axis. At this time, when the rotational load torque of the output shaft portion 41 is smaller than the brake torque, the relative rotation of the first ring gear 30 with respect to the stationary body 2 is prevented. Accordingly, the planetary gear 20 revolves while rotating due to the rotation of the sun gear 10, and the second ring gear (third gear member) 40 rotates due to the revolution of the planetary gear 20, and the drive motor is driven to the outside via the output shaft portion 41. 1 power can be output.

  In this case, as described above, the fixed body 2 and the first ring gear 30 are in a state in which relative rotation is prevented by fitting the curved convex portion 80c and the concave portion 35 of the wave washer 80 to each other. Therefore, micro slip does not occur between the fixed body 2 and the first ring gear 30 unless the fitting state of the curved convex portion 80c and the concave portion 35 is released. In addition, the set load of the wave washer 80 is only required to prevent the curved convex portion 80 c from escaping from the concave portion 35, and the first load is set only by the frictional force between the fixed body 2 and the first ring gear 30. It is possible to set the ring gear 30 to be smaller than that which restricts the rotation of the ring gear 30. Thereby, it is not necessary to set the rigidity of each part of the power transmission device to be large, and it becomes possible to suppress the increase in the size of the device and the increase in the manufacturing cost.

  On the other hand, when the rotational load torque of the output shaft portion 41 exceeds the brake torque in the above-described state, the wave washer 80 is pushed by the action of the inclined surfaces 80d and 35a that are in contact with each other between the curved convex portion 80c and the concave portion 35. The fitting state between the curved convex portion 80 c and the concave portion 35 is released against the pressure, and the first ring gear 30 rotates with respect to the fixed body 2, and the power transmission to the second ring gear 40 is cut off.

  When the rotational load torque of the output shaft portion 41 again falls below the brake torque from the above state, the fitting state between the curved convex portion 80c and the concave portion 35 is continued, and the second ring gear 40 is rotated by the rotation of the sun gear 10. The power of the drive motor 1 can be output to the outside through the output shaft portion 41 by rotating.

  Thus, according to the power transmission device, power transmission to the output shaft portion 41 can be interrupted without requiring an actuator or a controller for controlling the driving of the actuator separately. In addition, as described above, when the curved convex portion 80c and the concave portion 35 are in the fitted state, microslip cannot occur, so that the first load is not required without increasing the set load of the wave washer 80. It is possible to reliably prevent the ring gear 30 from rotating. Thereby, for example, when the power transmission device is applied to the positioning mechanism, it is possible to ensure high accuracy.

(Embodiment 3)
6 to 8-2 show a power transmission apparatus according to Embodiment 3 of the present invention. The power transmission device illustrated here is applied to an actuator unit using the drive motor 1 as a drive source, as in the first embodiment. A sun gear (first gear member) 10 is attached to the drive shaft 1 a of the drive motor 1. I have. The sun gear 10 is a spur gear having an outer peripheral gear portion 10a on the outer peripheral portion, and is fixed to the drive shaft 1a of the drive motor 1 in a state where the shaft centers thereof are matched. The sun gear 10 has a mysterious gear mechanism formed by meshing a first ring gear 130 (second gear member) and a second ring gear (third gear member) 40 via a plurality of planetary gears (intermediate gear members) 20. It is.

  The planetary gear 20 is a spur gear having an outer peripheral gear portion 20 a on the outer peripheral portion and an integral shaft. Three planetary gears 20 are arranged around the sun gear 10. These planetary gears 20 are supported by a pair of upper and lower planetary carriers 21 in such a manner that their respective axes are parallel to the axis of the sun gear 10 and are equally spaced from each other. The planetary carrier 21 located below in FIG. 6 has a sliding hole 21a formed in the bottom wall. This sliding hole 21a rotates the planetary carrier 21 around the axis of the drive shaft 1a with respect to the main body case 1b by fitting the protrusion 1c provided on the main body case 1b of the drive motor 1 to be slidable. Support as possible. Each planetary gear 20 supported by the planetary carrier 21 meshes with the sun gear 10 via the outer peripheral gear portion 20a, and each of the planetary gears 20 can rotate around its own axis and can be rotated by the planetary carrier 21. It can revolve around its axis.

  The first ring gear 130 has a bottomed cylindrical shape, and has an inner peripheral gear portion 130a on an inner peripheral surface thereof and an outer peripheral gear portion 130b on an outer peripheral surface thereof. The first ring gear 130 rotates about the axis of the drive shaft 1a with respect to the main body case 1b by fitting the lower protrusion of the planetary carrier 21 in a sliding hole 130c provided in the bottom wall so as to be slidable. Is possible.

  The second ring gear 40 has a bottomed cylindrical shape, and has an inner peripheral gear portion 40a on the inner peripheral surface thereof, and an output shaft portion 41 that is integral with a portion that is on its own axial center on the outer surface of the bottom wall. It is what has. When compared with the first ring gear 130 described above, the second ring gear 40 has a slightly smaller outer diameter, and an inner circumference formed on the inner circumference of the first ring gear 130 with the number of teeth of the inner circumference gear portion 40a. The gear part 130a is configured to be different from each other. The second ring gear 40 can be rotated around the axis of the drive shaft 1 a by making the opening face the opening of the first ring gear 130, and the planetary carrier 21 can be interposed between the second ring gear 40 and the first ring gear 130. The three planetary gears 20 including the sun gear 10 and the sun gear 10 are accommodated.

  On the other hand, the power transmission device includes a brake shaft member 150. The brake shaft member 150 is attached to the support member 5 attached to the main body case 1 b of the drive motor 1, and its own axis is parallel to the axis of the drive shaft 1 a at a portion that becomes the outer periphery of the first ring gear 130. It is arranged in a state. The brake shaft member 150 is provided with a flywheel gear (fourth gear member) 160 and a contact body 170.

  The flywheel gear 160 is a spur gear having an outer peripheral gear portion 160a on the outer peripheral portion, and can rotate around the axis of the brake shaft member 150 and can slide along the axial direction of the brake shaft member 150. It arrange | positions at the brake shaft member 150 so that it may become. The flywheel gear 160 is configured with a large mass so that a large inertia force can be obtained when the flywheel gear 160 rotates around the axis of the brake shaft member 150. The contact body 170 is a disk-like member fixed at a position where the flywheel gear 160 is sandwiched between the brake shaft member 150 and the support member 5, and has an outer diameter substantially equal to that of the flywheel gear 160. is there.

  The flywheel gear 160 is provided with a plurality of convex portions 161 on the outer periphery of the surface facing the contact body 170, while the contact body 170 has an outer periphery on the surface facing the flywheel gear 160. A plurality of concave portions 171 are provided in the portion. The convex portion 161 is formed in a substantially trapezoidal shape such that the width gradually decreases as it protrudes, and has inclined surfaces 161a on both sides. The concave portion 171 is formed in a shape and size that can fit the convex portion 161 of the flywheel gear 160, and has an inclined surface 171 a that faces the inclined surface 161 a and is provided on the flywheel gear 160. The number and position are adjusted so that all of the plurality of convex portions 161 can be fitted together.

  Furthermore, a pressing spring 180 is interposed between the support member 5 and the flywheel gear 160 in the power transmission device. The pressing spring 180 applies a preset brake torque to the first ring gear 130 via the flywheel gear 160 by constantly pressing the end surface of the flywheel gear 160 against the end surface of the contact body 170. In the third embodiment, the pressing spring 180 is configured by arranging a coil spring wound in a coil shape on the outer peripheral portion of the brake shaft member 150.

  Here, in the power transmission device, as described above, the convex portion 161 formed on the flywheel gear 160 and the concave portion 171 formed on the contact body 170 are fitted to each other. On the other hand, in order to relatively rotate the flywheel gear 160, it is necessary to release the fitting state between the convex portion 161 and the concave portion 171. That is, when the rotational force from the drive motor 1 acts on the flywheel gear 160 via the sun gear 10, the planetary gear 20, and the first ring gear 130, the functions of the inclined surfaces 161 a and 171 a that come into contact with each other in the convex portion 161 and the concave portion 171. Thus, the flywheel gear 160 moves away from the contact body 170 against the pressing force of the pressing spring 180, and the fitting state between the convex portion 161 and the concave portion 171 is released. Therefore, the brake torque by the pressing spring 180 is equivalent to the rotational torque required to release the fitting state between the convex portion 161 and the concave portion 171.

  In the power transmission device configured as described above, when the drive motor 1 is driven, the sun gear 10 rotates in one direction around its own axis. At this time, when the rotational load torque of the output shaft portion 41 is smaller than the brake torque, the relative rotation of the flywheel gear 160 with respect to the contact body 170 is prevented, and the relative rotation of the first ring gear 130 with respect to the drive motor 1 is prevented. The rotation is blocked. Accordingly, the planetary gear 20 revolves while rotating due to the rotation of the sun gear 10, and the second ring gear 40 rotates due to the revolution of the planetary gear 20, and the power of the drive motor 1 is output to the outside via the output shaft portion 41. be able to.

  In this case, as described above, the contact body 170 and the flywheel gear 160 are in a state in which relative rotation is prevented by fitting the convex portion 161 and the concave portion 171 to each other. Therefore, micro slip does not occur between the contact body 170 and the flywheel gear 160 unless the fitting state of the convex portion 161 and the concave portion 171 is released. Micro slip does not occur in the meshing first ring gear 130. In addition, the set load of the pressing spring 180 may be of a level that prevents the convex portion 161 from deviating from the concave portion 171, and only by the frictional force between the contact body 170 and the flywheel gear 160. It is possible to set the flywheel gear 160 smaller than that which restricts the rotation of the flywheel gear 160. Thereby, it is not necessary to set the rigidity of each part of the power transmission device to be large, and it becomes possible to suppress the increase in the size of the device and the increase in the manufacturing cost.

  On the other hand, when the rotational load torque of the output shaft portion 41 exceeds the brake torque in the above-described state, the pressing spring 180 is acted on by the curved inclined surfaces 161a and 171a that are in contact with each other between the convex portion 161 and the concave portion 171. The fitting state between the convex portion 161 and the concave portion 171 is released against the pressing force of the first, the flywheel gear 160 rotates with respect to the contact body 170, and the first ring gear 130 is further driven by the drive motor. By rotating with respect to 1, the power transmission to the second ring gear 40 is cut off.

  When the rotational load torque of the output shaft portion 41 again falls below the brake torque from the above state, the fitting state between the convex portion 161 and the concave portion 171 is continued, and the second ring gear 40 is rotated by the rotation of the sun gear 10. And the power of the drive motor 1 can be output to the outside via the output shaft portion 41.

  Thus, according to the power transmission device, power transmission to the output shaft portion 41 can be interrupted without requiring an actuator or a controller for controlling the driving of the actuator separately. In addition, as described above, when the convex portion 161 and the concave portion 171 are in the fitted state, microslip cannot occur, so that the fly load is not required without increasing the set load of the pressing spring 180. It is possible to reliably prevent the wheel gear 160 and the first ring gear 130 from rotating. Thereby, for example, when the power transmission device is applied to the positioning mechanism, it is possible to ensure high accuracy.

  In the first to third embodiments described above, a wonder gear mechanism having two ring gears is exemplified, but a planetary gear mechanism having one ring gear may be applied. Is possible. Moreover, although the sun gear is used as an input element and the ring gear is used as an output element, the input element and the output element can be arbitrarily changed.

  Furthermore, in Embodiment 1 mentioned above, while providing the convex part in the 1st ring gear, while forming the concave part in the contact member, a convex part and a concave part may be a reverse aspect. Similarly, in the second embodiment, a concave portion is formed in the first ring gear, while a curved convex portion is formed in the wave washer. In the third embodiment, a convex portion is provided in the flywheel gear, while the contact body is provided with a convex portion. Although the concave portion is provided, the concave and convex portions may be formed in the opposite manner.

DESCRIPTION OF SYMBOLS 1 Drive motor 10 Sun gear 20 Planetary gear 21 Planetary carrier 30 1st ring gear 33 Convex part 33a Inclined surface 35 Concave part 35a Inclined surface 40 2nd ring gear 41 Output shaft part 60 Contact member 61 Concave part 61a Inclined surface 70 Pressing spring 80 Wave washer 80c Curved convex portion 80d Inclined surface 130 First ring gear 150 Brake shaft member 160 Flywheel gear 161 Convex portion 161a Inclined surface 170 Contact body 171 Concave portion 171a Inclined surface 180 Press spring

Claims (5)

A first gear member disposed rotatably about its own axis;
An intermediate gear member meshed with the first gear member, supported by a carrier so as to be rotatable about its own axis and revolved about the axis of the first gear member;
A second gear member having an inner peripheral gear portion on an inner peripheral portion, rotatably disposed about an axis of the first gear member, and meshing with the intermediate gear member via the inner peripheral gear portion; ,
Brake means for applying a brake torque having a preset magnitude using any one of the first gear member, the second gear member, and the carrier as a stop element, and the rest not applying the brake torque of the brake means A power transmission device having one of the two as an input element and the other as an output element,
The brake means regulates relative rotation with the stop element by engaging with the stop element via an inclined surface, and tilts when a rotational torque exceeding the brake torque is applied to the stop element. A power transmission device that allows relative rotation with the stop element by relatively moving apart by an action. A first gear member disposed rotatably about its own axis;
An intermediate gear member that meshes with the first gear member, is rotatable about its own axis, and is revolved around the axis of the first gear member;
A second gear member having an inner peripheral gear portion on an inner peripheral portion, rotatably disposed about an axis of the first gear member, and meshing with the intermediate gear member via the inner peripheral gear portion; ,
The inner peripheral gear portion has an inner peripheral gear portion having a number of teeth different from that of the inner peripheral gear portion of the second gear member, and is disposed rotatably around the axis of the first gear member. A third gear member meshing with the intermediate gear member via
Brake means for applying a brake torque having a preset magnitude with the second gear member as a stop element, the power transmission apparatus using the first gear member as an input element and the third gear member as an output element Because
The brake means regulates relative rotation with the second gear member by engaging with the second gear member through an inclined surface, while a rotational torque exceeding the brake torque is applied to the second gear member. And a power transmission device that allows relative rotation with the second gear member by being moved relatively apart by a tilting action. The brake means includes
An inclined surface formed on the stop element;
A contact member having an inclined surface that contacts the inclined surface of the stop element;
The power transmission device according to claim 1, further comprising: a pressing member that presses the inclined surface of the abutting member against the inclined surface of the stop element. The brake means includes
An inclined surface formed on the stop element;
The power transmission device according to claim 1, further comprising: a pressing member that presses the stop element via the inclined surface. The second gear member has an outer peripheral gear portion on the outer peripheral portion,
The brake means includes
A fourth gear member having an outer peripheral gear portion at the outer peripheral portion and disposed rotatably around its own axis in a state where the outer peripheral gear portion is engaged with the outer peripheral gear portion of the second gear member;
A brake shaft member that supports the fourth gear member so as to be rotatable and slidable along the axial direction;
An abutting portion provided in a state in which movement in the axial direction is restricted at a tip portion of the brake shaft member;
The power according to claim 2, further comprising: a pressing member that presses the fourth gear member against the contact portion, and the inclined surface is provided between the fourth gear member and the contact portion. Transmission device.

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