JP5393415B2 - Power transmission device - Google Patents

Description

  The present invention relates to a power transmission device, and more particularly to a power transmission device that switches the output destination of power from one drive source.

  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 power of the charge motor is transmitted to the charge unit mechanism to perform shutter charging, and then the power of the charge motor is transmitted to the flywheel. The generated vibration is reduced. For switching the power, a planetary gear mechanism is applied. For example, a planetary carrier is connected to a charge unit mechanism, and a ring gear is connected to a flywheel.

  In this power transmission device, the power of the charge motor is transmitted to the charge unit mechanism by restricting the rotation of the ring gear, and shutter charging can be performed. On the other hand, when the rotation of the planetary carrier is restricted while the ring gear is allowed to rotate, the output destination of the power from the charge motor is switched to the flywheel, and the vibration of the camera is reduced by the inertial force of the flywheel. .

JP 2008-58545 A

  By the way, in order to switch the rotation of the ring gear and the planetary carrier between a restricted state and an allowed state, an actuator and a controller for controlling the driving of the actuator are essential. For this reason, when the power transmission device of Patent Document 1 is applied, not only the manufacturing cost is remarkably increased, but also the size of the application target such as a camera is increased.

  In view of the above circumstances, an object of the present invention is to provide a power transmission device capable of switching a power output destination without causing an increase in manufacturing cost or an increase in the size of an application target.

  In order to achieve the above object, a power transmission device according to the present invention is disposed so as to be rotatable about its own axis, and is engaged with a first gear member driven by a driving source and the first gear member. An intermediate gear member that is rotatable about its own axis and revolved around the axis of the first gear member, and an inner peripheral gear portion on an inner peripheral portion, A second gear member that is rotatably arranged around the shaft center and meshes with the intermediate gear member via an inner peripheral gear portion is different from an inner peripheral gear portion of the second gear member at an inner peripheral portion. A third gear member having an inner peripheral gear portion having the number of teeth, rotatably disposed about the axis of the first gear member, and meshing with the intermediate gear member via the inner peripheral gear portion; Brake means for applying a preset brake torque to the second gear member, A first gear member and an input element, and characterized in that the output element of the second gear member and the third gear member.

  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 contact member, a contact body provided in a state in which movement of the brake shaft member in the axial direction is restricted, and pressing the fourth gear member against the contact body. The fourth gear member includes a pressing member that applies the brake torque.

  According to the present invention, when the rotational load torque acting on the third gear member is lower than the brake torque, when the first gear member is driven, the rotation of the second gear member is restricted, so that the third gear member is It is rotated. On the other hand, when the rotational load torque acting on the third gear member exceeds the brake torque, the rotation of the third gear member is restricted even when the first gear member is driven, and the second gear is overcome by overcoming the brake torque. The member will be rotated. As a result, it becomes possible to switch the power output destination between the second gear member and the third gear member without requiring a separate actuator or a controller for controlling the driving of the actuator. There is no fear of inviting.

FIG. 1 is a cross-sectional side view conceptually showing a power transmission device according to an embodiment of the present invention. 2 is a cross-sectional plan view of the power transmission device shown in FIG. 3 is an external perspective view of the power transmission device shown in FIG.

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

  1 to 3 show a power transmission device according to an embodiment of the present invention. The power transmission device illustrated here is provided between a charge unit mechanism C that performs shutter charging of a camera and a charge motor M that is a driving source thereof. The charge motor M is, for example, an ultrasonic motor, and includes a sun gear (first gear member) 10 on its drive shaft MS. 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 MS of the charge motor M 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 MS with respect to the main body case MC by slidably fitting the protrusion MCe provided on the main body case MC of the charge motor M. 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 a bottomed cylindrical shape, and has an inner peripheral gear portion 30a on its inner peripheral surface and an outer peripheral gear portion 30b on its outer peripheral surface. The first ring gear 30 rotates about the axis of the drive shaft MS with respect to the main body case MC by slidably fitting the lower projection of the planetary carrier 21 into a slide hole 30c provided in the bottom wall. 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 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 can be rotated around the axis of the drive shaft MS by making the opening face the opening of the first ring gear 30, and the planetary carrier 21 can be interposed between the second ring gear 40 and the first ring gear 30. 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 50. The brake shaft member 50 is attached to a support member B attached to the main body case MC of the charge motor M, and its own axis is parallel to the axis of the drive shaft MS at a portion that is the outer periphery of the first ring gear 30. It is arranged in a state. The brake shaft member 50 is provided with a flywheel gear (fourth gear member) 60 and a contact body 70.

  The flywheel gear 60 is a spur gear having an outer peripheral gear portion 60a on the outer peripheral portion, and can rotate around the axis of the brake shaft member 50 and can slide along the axial direction of the brake shaft member 50. It arrange | positions at the brake shaft member 50 so that it may become. The flywheel gear 60 is configured with a large mass so that a large inertial force can be obtained when the flywheel gear 60 rotates around the axis of the brake shaft member 50. The contact body 70 is a disk-like member fixed at a position where the flywheel gear 60 is sandwiched between the brake shaft member 50 and the support member B, and has an outer diameter substantially equal to that of the flywheel gear 60. is there.

  Further, in the power transmission device, a pressing spring (pressing member) 80 is interposed between the support member B and the flywheel gear 60. The pressing spring 80 applies a preset braking torque to the first ring gear 30 via the flywheel gear 60 by constantly pressing the end surface of the flywheel gear 60 against the end surface of the contact body 70. In the present embodiment, the pressing spring 80 is configured by arranging a coil spring wound in a coil shape on the outer peripheral portion of the brake shaft member 50.

  The power transmission device configured as described above is mounted on the camera in a state where the output shaft portion 41 is linked to the charge unit mechanism C so that shutter charging is performed when the output shaft portion 41 of the second ring gear 40 rotates. To do.

  Now, when the charge motor M is driven to perform shutter charging in this camera, the sun gear 10 rotates in one direction around its own axis. At this time, in the power transmission device, since the flywheel gear 60 is in pressure contact with the contact body 70 by the pressing spring 80, the frictional force acting between the flywheel gear 60 and the contact body 70 is used. The rotation of the flywheel gear 60 is restricted, and the rotation of the first ring gear 30 meshing with the flywheel gear 60 is restricted. 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, so that shutter charging is performed via the output shaft portion 41.

  When the shutter charge is completed and the charge unit mechanism C reaches the charge end, the rotation of the output shaft portion 41 is prevented by the charge unit mechanism C and the rotational load torque of the second ring gear 40 exceeds the brake torque. . In this state, the rotation of the sun gear 10 allows the flywheel gear 60 to rotate against the frictional force acting between the contact body 70 and the flywheel gear 60 to rotate via the first ring gear 30. It will be. Thereby, the vibration of the camera can be reduced by the inertial force of the flywheel gear 60. Note that the charge unit mechanism C returns to the initial state at an appropriate timing, and if the shutter charge is performed again, the flywheel gear 60 will rotate each time thereafter.

  Here, according to the power transmission device, the output destination of the charge motor M is automatically switched to the flywheel gear 60 when the rotational load torque of the second ring gear 40 exceeds the brake torque. And no controller for controlling the actuator drive. Moreover, if the rotational load torque of the second ring gear 40 is removed, the output destination of the charge motor M automatically returns to the second ring gear 40 again. Therefore, the manufacturing cost can be reduced, and there is no fear of increasing the size of the camera to be applied.

  In the above-described embodiment, the power transmission mechanism interposed between the charge motor M of the camera and the shutter charge mechanism is illustrated, but the first gear member is used as an input element, and the second gear member and If the third gear member is an output element, it is of course possible to apply it to others.

  In the embodiment described above, an ultrasonic motor is applied as a drive source. However, an ultrasonic motor is not necessarily applied, and for example, a stepping motor or a DC motor may be applied.

  Further, in the above-described embodiment, the brake torque is applied to the second gear member by engaging the fourth gear member pressed by the pressing member with the second gear member. Not. For example, it is possible to apply the brake torque even when the second gear member is directly pressed against the fixed body by the pressing member.

  Furthermore, in the above-described embodiment, the planetary gear 20 is supported by the planetary carrier 21, but when the mysterious gear mechanism is configured as in the embodiment, it is not always necessary to support the planetary gear by the planetary carrier. A planetary gear may simply be interposed between the sun gear and the ring gear.

DESCRIPTION OF SYMBOLS 10 Sun gear 10a Outer periphery gear part 20 Planetary gear 20a Outer periphery gear part 21 Planetary carrier 30 1st ring gear 30a Inner periphery gear part 30b Outer periphery gear part 40 Second ring gear 40a Inner periphery gear part 41 Output shaft part 50 Brake shaft member 60 Flywheel gear 60a Peripheral gear part 70 Contact body 80 Pressing spring M Charge motor

Claims (1)

A first gear member rotatably disposed about its own axis and driven by a drive source;
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
Braking means for applying a brake torque having a preset magnitude to the second gear member, the first gear member as an input element, and the second gear member and the third gear member as an output element. and to have,
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 body provided in a state in which movement in the axial direction is restricted at the tip of the brake shaft member;
A pressing member that applies the brake torque to the fourth gear member by pressing the fourth gear member against the contact body;
Power transmission apparatus characterized by comprising a.

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