JP5458928B2 - Rotation drive - Google Patents

Description

  The present invention relates to a rotary drive device.

  As one type of rotary drive device, one shown in Patent Document 1 is known. As shown in FIGS. 1 and 2 of Patent Document 1, the rotation driving device is a surface wave motor that uses ultrasonic vibration of a piezoelectric body. The surface wave motor includes a stator 4 in which a piezoelectric body 4b is fixed to an elastic body 4a and a rotor 2 having a traveling wave passive surface 2a in mutual contact with a traveling wave generating surface 4c of the stator 4. This is the structure. In this surface wave motor, the traveling wave generating surface 4c is waved by applying a voltage to the piezoelectric body 4b and is received by the traveling wave passive surface 2a so that the rotor 2 rotates.

  Moreover, what is shown by patent document 2 is known as a drive device. As shown in FIG. 1 in Patent Document 2, the driving device is formed in a semi-annular shape, and the piezoelectric body 15 is attached to two symmetrical locations, and a voltage is applied to the piezoelectric body 15 to obtain 2 The tips of the legs 12 and 13 of the book are rotated in an elliptical shape so that the contacting object (rail 21) is moved in one direction.

  Furthermore, what is shown by patent document 3 is known as a drive device. As shown in FIGS. 1, 2, and 18 in Patent Document 3, in the driving device, piezoelectric plates 18, 20, 22, and 24 are respectively attached to four outer surfaces 37 of a rectangular prism housing 14. In such a drive, the interaction of the activated transducers (eg plates 18, 20, 22 and 24) and the housing 14 causes the orbital movement of the nut 16, which on the other hand of the threaded shaft 12 Causes rotation and translation. As a result, the housing 14 moves in one direction.

JP-A-62-77068 Japanese Patent Laid-Open No. 02-266881 Special table 2008-510445 gazette

  According to the rotation drive device described in Patent Document 1, the rotor 2 is rotated by applying a voltage to the piezoelectric body. However, the torque that can be output is smaller than that of the electric motor due to its structure. There's a problem.

  Further, according to the driving device described in Patent Document 2, since the vibration part that rotates in an elliptical shape is pressed against the object (rail 21) to be driven and driven, only the friction of the contacting part is propelled. There is a problem that power cannot be obtained.

  Further, according to the drive device described in Patent Document 3, when the housing 14 side is deformed, the screws of the housing 14 and the shaft 12 rub against each other, and the shaft 12 is rotated by the friction of the contact surface of the screw. In other words, since the propulsion is carried out only with this frictional force, there is a problem that an increase in propulsive force cannot be expected.

  The present invention has been made to solve the above-described problems, and it is an object of the present invention to obtain a relatively large driving force with a simple configuration and to easily control the driving force in a rotary driving device. To do.

  In order to solve the above-mentioned problem, the structural feature of the invention according to claim 1 includes a main body case, and an internal tooth or an external tooth that is rotatably supported by the main body case and formed in an output shaft and an annular shape. An output rotator that rotates around the output shaft's rotation axis, and makes an orbiting motion eccentrically with respect to the output shaft's rotation shaft, and meshes with the internal teeth of the output rotator when performing the eccentric orbiting motion. An eccentric rotator having internal teeth that mesh with external teeth to be rotated or external teeth of the output rotator, and a weight that contacts the eccentric rotator along an annular wall formed around the rotation axis of the output shaft and circulates And a support device that supports the eccentric rotator so as to be elastically movable, and a strain element that vibrates the eccentric rotator by strain generated in response to an electric signal, and a pressing force by the strain element and an elastic force by the support device Rotating the weight in cooperation with the centrifugal force of the weight An eccentric motion generating device for generating an eccentric orbital motion to the eccentric rotation body, is that with the.

  Further, the structural feature of the invention according to claim 2 is that, in claim 1, the support device comprises an elastic member interposed between the main body case and the eccentric rotator, and the eccentric rotator is attached to the main body case. The strain element is supported on the main body case so as to be elastically movable, and presses the eccentric rotator by a strain generated according to an electric signal.

  According to a third aspect of the present invention, the support device according to the first aspect is configured such that the support device is fixed to the body case and is elastically deformable, and between the first support device and the eccentric rotating body. A second support device comprising an elastic member interposed between the first support device and the second support device for elastically moving the eccentric rotating body with respect to the first support device. The eccentric rotating body is vibrated by vibrating the first support device by the generated strain.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the strain element is any one of a piezoelectric element, a magnetostrictive element, an electrostrictive element, and a shape memory element. It is comprised by.

  The structural feature of the invention according to claim 5 is that in any one of claims 1 to 4, a weight position detection sensor for detecting the position of the weight is further provided.

  A structural feature of the invention according to claim 6 is that, in claim 2, the strain element is provided so as to press the eccentric rotating body in a tangential direction of the annular wall.

  Further, the structural feature of the invention according to claim 7 is that in claim 3, the first support device is formed of an elastic material so that the base end is fixed to the main body case, the tip is a free end, and surrounds the eccentric rotating body. The strain element is attached to the proximal end portion of the first support device.

  The structural feature of the invention according to claim 8 is that, in claim 7, the support device is configured such that the amplitude of the first support device increases as it goes to the tip of the first support device. .

  In the invention according to claim 1 configured as described above, when the weight circulates along the annular wall formed in the eccentric rotator, the eccentric rotator supported by the support device so as to be elastically movable is the centrifugal centrifugal force. An eccentric orbiting motion is performed around the rotation axis of the output shaft of the output rotator by the force and the elastic force of the support device. The strain element vibrates the eccentric rotator, thereby starting the eccentric circular motion described above, and controlling the eccentric circular motion by accelerating and decelerating. When the eccentric rotor rotates in an eccentric manner, the output rotor is rotated by meshing the internal teeth of the eccentric rotor with the external teeth of the output rotor or the external teeth of the eccentric rotor with the internal teeth of the output rotor. .

  As described above, even when a strain element having a relatively small displacement amount is used, it is possible to apply a force necessary for the occurrence of the eccentric rotating motion to the eccentric rotating body. Once the eccentric orbiting motion is started, a stable orbiting motion can be achieved by the pressing force by the strain element, the centrifugal force of the weight, and the elastic force by the support device. In addition, the eccentric rotating body is not rotated only by the pressing force of the strain element, but the output rotating body is rotated by moving the eccentric rotating body eccentrically using the elastic force of the support device and the centrifugal force of the weight. Can be made.

  Therefore, a relatively large driving force can be obtained with a simple configuration. Further, since the driving force has a good correlation with the centrifugal force of the weight, the driving force can be easily controlled by controlling the rotation (circulation) state of the weight.

  In the invention according to claim 2 configured as described above, in claim 1, the support device is composed of an elastic member interposed between the main body case and the eccentric rotator, and the eccentric rotator is attached to the main body case. The strain element is fixed to the main body case and presses the eccentric rotator by strain generated according to an electric signal. Accordingly, the eccentric rotating body can be reliably supported on the main body case via the elastic member, and the eccentric rotating body can be reliably vibrated by the strain element fixed to the main body case.

  In the invention according to claim 3 configured as described above, in claim 1, the support device is a first support device fixed to the main body case and capable of elastic deformation, and between the first support device and the eccentric rotating body. And a second support device configured to elastically move the eccentric rotating body with respect to the first support device. The strain element is attached to the first support device according to an electrical signal. The eccentric rotating body is vibrated by vibrating the first support device due to the strain generated in this manner. Accordingly, the eccentric rotator can be reliably supported on the main body case via the second support device made of an elastic member and the first support device that can be elastically deformed, and a relatively large vibration can be applied to the eccentric rotator. . Further, since the strain element directly vibrates the first support device and the eccentric rotating body is vibrated by the vibrated first support device, the eccentric rotating body can be more reliably vibrated by the strain element.

  In the invention according to claim 4 configured as described above, in any one of claims 1 to 3, the strain element is any one of a piezoelectric element, a magnetostrictive element, an electrostrictive element, and a shape memory element. It is composed of Thereby, the amount of distortion can be changed according to the electric signal to be supplied, and the rotation control of the eccentric rotator and the rotation drive device can be easily performed.

  The invention according to claim 5 configured as described above further includes a weight position detection sensor for detecting the position of the weight in any one of claims 1 to 4. Thus, the strain element can be controlled more reliably by reliably detecting the position of the weight.

  In the invention according to claim 6 configured as described above, in claim 2, the strain element is provided so as to press the eccentric rotating body in the tangential direction of the annular wall. Can be effectively added to the eccentric rotating body and thus to the weight, and the efficiency can be improved.

  In the invention according to claim 7 configured as described above, in claim 3, the first support device is made of an elastic material so that the base end is fixed to the body case, the tip is a free end, and surrounds the eccentric rotating body. The strain element is formed and attached to the proximal end of the first support device. Thus, the first support device can support the eccentric rotating body with a simple configuration so as to be elastically deformable. Moreover, since the strain element is attached to the base end portion of the first support device, the eccentric rotating body can be vibrated efficiently.

  In the invention according to claim 8 configured as described above, in claim 7, the support device is configured such that the amplitude of the first support device increases toward the tip of the first support device. Thereby, even if the vibration of the base end portion of the first support device is small, a large amplitude can be ensured by going to the tip, so that the eccentric rotating body can be vibrated more efficiently.

It is sectional drawing which shows 1st Embodiment of the rotational drive apparatus by this invention. It is sectional drawing which shows the rotational drive apparatus shown in FIG. 1 along the 2-2 line. It is sectional drawing which shows the rotational drive apparatus shown in FIG. 1 along the 3-3 line. It is a figure which shows the action | operation at the time of the start of the rotational drive apparatus shown in FIG. It is a figure which shows the action | operation at the time of the start of the rotational drive apparatus shown in FIG. It is a figure which shows the action | operation at the time of eccentric rotation motion of the rotational drive apparatus shown in FIG. It is a figure which shows the action | operation at the time of eccentric rotation motion of the rotational drive apparatus shown in FIG. It is a figure which shows the action | operation at the time of eccentric rotation motion of the rotational drive apparatus shown in FIG. It is a figure which shows the action | operation at the time of eccentric rotation motion of the rotational drive apparatus shown in FIG. It is a figure which shows the action | operation when the weight comes to the predetermined position at the time of the eccentric rotation motion of the rotational drive apparatus shown in FIG. It is sectional drawing which shows 2nd Embodiment of the rotational drive apparatus by this invention. It is sectional drawing which shows the rotational drive apparatus shown in FIG. 11 along 12-12 line.

1) First Embodiment Hereinafter, a first embodiment of a rotary drive device according to the present invention will be described with reference to the drawings. 1 is a cross-sectional view of the rotary drive device, FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a cross-sectional view taken along line 3-3 of FIG.

  The rotation drive device 10 includes a main body case 11, an output rotator 12, an eccentric rotator 13, and an eccentric motion generator 20.

The main body case 11 is formed in a box shape from a metal material or a synthetic resin material.
The output rotator 12 is formed of a metal material or a synthetic resin material. The output rotating body 12 includes a main body 12a formed in a disk shape. An output shaft 12b is coaxially provided at the center of the main body 12a. The output shaft 12b is rotatably supported by a bearing 11a attached to the main body case 11. Therefore, the output rotating body 12 is rotatably supported by the main body case 11 and is rotated around the rotation axis of the output shaft 12b. The main body 12 a of the output rotating body 12 is accommodated in the main body case 11. The output shaft 12 b is disposed so as to protrude from the main body case 11.

  The output rotating body 12 is provided with an inner tooth 12c formed in an annular shape. Specifically, in the present embodiment, an annular convex portion 12d is formed on the outer peripheral edge portion of the main body 12a. Internal teeth 12c are formed over the entire circumference on the inner circumferential surface of the annular convex portion 12d.

  The eccentric rotating body 13 is formed of a metal material, a synthetic resin material, or the like. The eccentric rotator 13 includes a main body 13a that is a box-shaped housing, and external teeth 13b provided on one side surface (lower surface) of the main body 13a. This eccentric rotator 13 is eccentric with respect to the rotation axis of the output shaft 12b of the output rotator 12 and makes a circular motion.

  The external teeth 13b are formed over the entire circumference on the outer peripheral surface of a convex portion 13c formed in a columnar shape (or cylindrical shape) on the lower surface of the main body 13a. The reference circle diameter (indicated by a dashed line in FIG. 2) of the external teeth 13b is smaller than the reference circle diameter (indicated by a dashed line in FIG. 2) of the internal teeth 12c, and the number of teeth of the external teeth 13b is the internal teeth 12c. Is set to less than the number of teeth. The convex portion 13c of the eccentric rotator 13 is inserted into the annular convex portion 12d of the output rotator 12, and when the eccentric rotator 13 is in a stopped state, the inner teeth 12c and the outer teeth 13b face each other with a space. Are arranged to be. The eccentric rotator 13 meshes with the internal teeth 12 c of the output rotator 12 and the external teeth 13 b of the eccentric rotator 13 when performing an eccentric orbiting motion. The eccentric orbiting motion is not a rotational motion (autorotation) in which the center of the rotating body is at the same location, but a rotational motion in which the center of the rotating body is not located at the same location. It is a rotating motion (revolution).

  An annular groove 13 d formed in an annular shape around the rotation axis of the output shaft 12 a of the output rotator 12 is provided in the main body 13 a of the eccentric rotator 13. The annular groove 13d includes an outer annular wall 13d1 (annular wall) and an inner annular wall 13d2 disposed coaxially on the inner side. The outer annular wall 13d1 and the inner annular wall 13d2 are erected on the bottom surface of the main body 13a. Note that the inner annular wall 13d2 may be omitted and only the outer annular wall 13d1 may be included. Further, the annular groove 13d may be circular or elliptical.

  A weight 21 that circulates along the outer annular wall 13d1 is provided in the annular groove 13d. The weight 21 is formed in a spherical shape. The weight 21 rotates around the outer annular wall 13d1 when the eccentric rotating body 13 makes an eccentric orbiting motion.

  The relationship between the weight 21 and the spring force (elastic force) of the support device 22 will be described. When the eccentric rotator 13 makes an eccentric orbiting motion, when the outer teeth 13b of the eccentric rotator 13 and the inner teeth 12c of the output rotator 12 mesh with each other, the rotational drive device 10 can output a preset minimum torque. As described above, the mass of the weight 21 and the spring force (elastic force) of the support device 22 are set.

  The mass of the weight 21 is preferably set so as to be larger than the mass of the eccentric rotating body 13. This is because the controllability is improved by making the centrifugal force of the weight 21 relatively large. Specifically, it is effective to set the mass of the weight that satisfies the following formula 1 at the minimum torque.

(Equation 1)
mRω ² > (rotational weight) + (elastic force of support device)
m is the weight of the weight 21, and R is the radius of the eccentric rotating body 13 around which the weight 21 rotates.

  The eccentric rotator 13 is supported via a support device 22 so as to be elastically movable. In the present embodiment, the support device 22 includes a plurality of coil springs 22 a interposed between the main body case 11 and the eccentric rotator 13, and supports the eccentric rotator 13 to be elastically movable with respect to the main body case 11. To do.

  Specifically, the main body 13a of the eccentric rotating body 13 is supported from a plurality of directions (for example, four directions) by a plurality of (for example, four) coil springs 22a1, 22a2, 22a3, and 22a4 with respect to the main body case 11. . Each coil spring 22a is interposed between the side surface of the main body 13a and the inner wall surface of the main body case 11 facing the side surface. One end of each coil spring 22 a is connected and fixed to the center in the longitudinal direction of each side surface of the main body 13 a, and the other end is connected and fixed to the center in the longitudinal direction of the inner wall surface of the main body case 11. The four coil springs 22a1, 22a2, 22a3, and 22a4 are set to the same length with the same spring constant.

  Thus, the eccentric rotator 13 is supported in a suspended state by the support device 22, that is, the four coil springs 22a1, 22a2, 22a3, and 22a4. When the eccentric rotator 13 is not rotating (when the rotation driving device 10 is in a non-driven state), the center 13e of the eccentric rotator 13 is connected to the rotation axis of the output rotator 12 (output shaft 12a). It is designed to be supported to match.

  In the present embodiment, the center 13e of the eccentric rotating body 13 is the center of the external tooth 13b. In the present embodiment, the center of the outer tooth 13b and the center of the outer annular wall 13d1 are coincident, but may not be coincident if the center of the outer tooth 13b exists inside the outer annular wall 13d1. This is because the centrifugal force of the weight 21 can be used.

  In addition to the coil spring, the elastic member may be a spring other than the coil spring, rubber, or a soft synthetic resin. Further, the support device may be configured by an elastic member formed in a single bar shape interposed between the top plate of the main body case 11 and the upper surface of the eccentric rotating body 13.

  A strain element 23 is provided in the main body case 11. The strain element 23 is fixed to the main body case 11. The strain element 23 is composed of a piezoelectric element, and presses and vibrates the eccentric rotator 13 by strain generated according to an electric signal. That is, the strain element 23 is formed in an elongated shape, and is arranged so that one end (base end) is fixed to the step portion 11 b of the main body case 11 and the other end (tip) is at a position where the eccentric rotating body 13 can be pressed. It is installed. The strain element 23 is provided so as to press the eccentric rotator 13 in the tangential direction of the outer annular wall 13d1.

  The distal end portion of the strain element 23 vibrates due to strain generated according to the electric signal. When the tip part moves inward (in a direction approaching the eccentric rotator 13), the eccentric rotator 13 is pressed, and when the tip part moves outward (in a direction away from the eccentric rotator 13), the eccentric rotator 13 is pressed. Do not press.

  The strain element 23 may be configured by any one of a magnetostrictive element, an electrostrictive element, and a shape memory element.

  The eccentric motion generator 20 includes the weight 21, the support device 22, and the strain element 23 described above, and the weight 21 is obtained by the cooperation of the pressing force by the strain element 23, the elastic force by the support device 22, and the centrifugal force of the weight 21. Is caused to generate an eccentric orbiting motion in the eccentric rotating body 13.

  The main body case 11 also includes a weight position detection sensor 14 that detects the position of the weight 21. One or a plurality of weight position detection sensors 14 are provided at any position on the locus (for example, the annular groove 13d) of the weight 21, and the position of the weight 21 is detected by detecting that the weight 21 has passed. It is supposed to be. For example, when the weight 21 is formed of a metal material, the weight position detection sensor 14 is configured by a sensor that can detect the metal material. In addition, when the weight position detection sensor 14 is comprised with a metal detection sensor, it is desirable to comprise the eccentric rotating body 13 mentioned above with a nonmetallic material (for example, synthetic resin material). This is because the detection capability of the weight position detection sensor 14 is exhibited.

  Next, the operation of the rotary drive device 10 configured as described above will be described. In addition, the case where the rotational drive apparatus 10 is installed so that the track surface of the circular motion of the eccentric rotator 13 may be a horizontal plane will be described.

  When the rotary drive device 10 is not driven, the eccentric rotator 13 has a coaxial positional relationship with the output rotator 12, that is, the rotation axis of the output shaft 12b and the center of the eccentric rotator 13 (central axis). The outer teeth 13b of the eccentric rotating body 13 and the inner teeth 12c of the output rotating body 12 are not meshed (see FIGS. 2 and 3).

  When an electrical signal (which may be a sine wave, a rectangular wave, or a triangular wave) is applied to the strain element 23, the tip of the strain element 23 starts to vibrate. Due to the vibration, the eccentric rotator 13 starts to vibrate along the pressing direction.

  That is, as shown in FIG. 4, when the tip of the strain element 23 swings in the direction of the arrow a1 (direction approaching the output shaft 12b), the eccentric rotating body 13 is pressed by the strain element 23 and attached to the support device 22. It moves toward one direction (direction of arrow b1 in FIG. 4) against the force. The directions of the arrows a1 and b1 are the same. Due to the movement of the eccentric rotating body 13 in the direction of the arrow b1, the weight 21 moves in the direction of the arrow c1 in FIG. 4 (clockwise direction in FIG. 4). This is because the weight 21 acts from the eccentric rotator 13 in the direction of the arrow b1, but moves along the outer annular wall 13d1.

  On the other hand, as shown in FIG. 5, when the tip of the strain element 23 swings in the direction of the arrow a2 that is opposite to the arrow a1 (the direction away from the output shaft 12b), the pressing by the strain element 23 against the eccentric rotator 13 is performed. Canceled. The eccentric rotating body 13 moves toward the opposite direction (the direction of the arrow b2 in FIG. 5) to return to the original position (position when not driven) by the urging force of the support device 22. The directions of the arrows a2 and b2 are the same. As the eccentric rotator 13 moves in the direction of arrow b2, the weight 21 moves in the direction of arrow c2 in FIG. 5 (counterclockwise direction in FIG. 5). This is because force acts on the weight 21 in the direction of the arrow b2 from the eccentric rotating body 13, but moves along the outer annular wall 13d1.

  Thus, when vibration (reciprocation) of the eccentric rotating body 13 is performed, the weight 21 also moves as described above in accordance with the vibration, so that the weight 21 starts circular motion along the annular groove 13d. . Then, when the centrifugal force of the weight 21 is applied to the eccentric rotator 13 that has reciprocated linearly, the eccentric rotator 13 becomes an elliptical motion, and thus starts an eccentric orbiting motion. During the eccentric orbiting motion of the eccentric rotator 13, the external teeth 13 b of the eccentric rotator 13 and the internal teeth 12 c of the output rotator 12 are engaged.

  In addition, during the stable eccentric orbiting movement, as shown in FIGS. 6 to 9, the eccentric rotating body 13 and the weight 21 are performing the eccentric orbiting movement in synchronization. Specifically, as shown in FIG. 6, when the external teeth 13b of the eccentric rotator 13 and the internal teeth 12c of the output rotator 12 mesh at the position of the coil spring 22a1, the weight 21 corresponds to the coil spring 22a1. It is in the position to do.

  Further, when the weight 21 rotates clockwise and reaches a position corresponding to the coil spring 22a2, the external teeth 13b of the eccentric rotator 13 and the internal teeth 12c of the output rotator 12 mesh with each other as shown in FIG. On the other hand, the eccentric rotator 13 rotates around to the position corresponding to the coil spring 22a2.

  Further, when the weight 21 rotates clockwise and reaches a position corresponding to the coil spring 22a3, the external teeth 13b of the eccentric rotator 13 and the internal teeth 12c of the output rotator 12 mesh with each other as shown in FIG. On the other hand, the eccentric rotator 13 rotates around to a position corresponding to the coil spring 22a3.

  Further, when the weight 21 rotates clockwise and reaches a position corresponding to the coil spring 22a4, the external teeth 13b of the eccentric rotator 13 and the internal teeth 12c of the output rotator 12 mesh with each other as shown in FIG. On the other hand, the eccentric rotator 13 rotates around to a position corresponding to the coil spring 22a4.

Thus, the eccentric rotator 13 performs a rotational motion (revolution) in which the center 13e moves along the predetermined circumference C, that is, an eccentric orbiting motion. At this time, when the rotational speed of the eccentric rotator 13 increases, the centrifugal force increases and the rotational force (torque) also increases. This is because the centrifugal force of the eccentric rotating body 13 conforms to the centrifugal force of the weight 21. The centrifugal force F of the weight 21 is expressed by M × r × ω ² . Here, M is the mass of the weight 21, r is the radius of the center of the weight 21, and ω is the angular velocity. The angular velocity is proportional to the number of rotations (angular velocity = 2π × number of rotations). In addition, the centrifugal force of the eccentric rotator 13 takes the largest value when the weight 12 and the eccentric rotator 13 make an eccentric orbiting motion in synchronization. Moreover, when the weight 12 and the eccentric rotator 13 perform an eccentric orbiting motion in synchronization, the eccentric orbiting motion of the eccentric rotator 13 can be stabilized.

  As described above, the torque of the rotary drive device 10 can be adjusted by the rotational speed (rotational speed, angular speed) of the eccentric rotating body 13, that is, the rotational speed (rotational speed, angular speed) of the weight 21. The output torque of the rotary drive device 10 can be adjusted by controlling the number.

  Adjustment of the rotational speed of the weight 21 (the rotational speed of the eccentric rotator 13) and synchronization of the circular motion of the eccentric rotator 13 and the weight 21 are controlled by pressing by the strain element 23. Specifically, when the weight 21 passes through a predetermined position of the annular groove 13d, the strain element 23 is controlled to press the eccentric rotating body 13 in the direction of arrow a1 (pressing direction) shown in FIGS. The As shown in FIG. 10, the predetermined position is a position where the tangential direction d <b> 1 at the position of the circulating weight 21 coincides with the pressing direction a <b> 1 by the strain element 23. In the present embodiment, the pressing direction a <b> 1 is a direction along the diagonal line of the main body case 11 (upward diagonal line in FIG. 10). If the main body 13a of the eccentric rotator 13 makes a circular motion while the inner surfaces of the eccentric rotator 13 move in parallel with respect to the main body case 11, the pressing direction a1 is a direction along the diagonal line of the main body 13a (upward diagonal line in FIG. 10). It is.

  When the eccentric rotating body 13 is pressed by the strain element 23 when the weight 21 rotating clockwise in FIG. 10 reaches a predetermined position, the pressing force of the strain element 23 can be applied to the weight 21 most efficiently. . The reason will be described below.

  The pressing force F by the strain element 23 acts on the eccentric rotator 13. Further, the weight 21 receives a vertical drag N (= Mg) from the eccentric rotating body 13. In the present embodiment, since the rotation driving device 10 is installed so that the locus of the eccentric rotating body 13 is horizontal, the weight 21 is in contact with the bottom surface of the main body 13a. Therefore, the vertical drag N is received from the bottom surface of the main body 13a. M is the mass of the weight 21 and g is the gravitational acceleration.

  Further, the eccentric rotator 13 is moved in the pressing direction by the pressing force F (in the direction of arrow a1 in FIG. 10) due to the pressing force F, and dragged by the eccentric rotator 13 causes the weight 21 to slide in the pressing direction. Since the friction coefficient μ (kinetic friction coefficient) is between the eccentric rotating body 13 and the weight 21, the weight 21 receives the frictional force f (= μN) from the eccentric rotating body 13. The frictional force f is in the same direction as the pressing force F. Accordingly, the weight 21 moves with the acceleration a (= μg) in the same direction as the pressing force F due to the frictional force f. That is, when the eccentric 21 is pressed by the strain element 23 when the weight 21 comes to a predetermined position, the weight 21 is accelerated.

  Further, the eccentric rotating body 13 is also accelerated by the pressing force F, but is biased by the support device 22. That is, while the weight 21 is accelerated, the eccentric rotator 13 is restricted from moving in the direction of acceleration acting on the weight 21. Therefore, the acceleration of the weight 21 is larger than the acceleration of the eccentric rotating body 13. Thus, when the eccentric rotator 13 is pressed by the strain element 23, the weight 21 is accelerated in the pressing direction. The accelerated weight 21 can rotate in synchronization with the eccentric rotator 13.

  When the acceleration direction of the weight 21 at this time is a direction other than the tangential direction of the annular groove 13d (outer annular wall 13d1), the force of the weight 21 applied in the acceleration direction receives a drag force from the outer annular wall 13d1. It becomes. Therefore, the acceleration of the weight 21 is reduced. On the other hand, when the acceleration direction of the weight 21 is the tangential direction of the annular groove 13d, it is possible to suppress the acceleration of the weight 21 from being reduced, so that the weight 21 can be efficiently accelerated.

  Whether the weight 21 is at the predetermined position is determined based on the detection result of the weight position detection sensor 14. Specifically, the rotational speed of the weight 21 is derived based on the detection result of the weight position detection sensor 14, that is, the current detection result and the previous detection result. Then, the position of the weight 21 is derived from the current detection result and the derived rotational speed of the weight 21, and the derived result is compared with a predetermined position. Further, the weight position detection sensor 14 is disposed at a position corresponding to the predetermined position, and the weight position detection sensor 14 detects the passage of the weight 21 to determine that the weight 21 is at the predetermined position. Good.

  As is clear from the above description, in the rotary drive device 10 according to the first embodiment, when the weight 21 circulates along the annular wall 13d1 formed in the eccentric rotating body 13, the support device 22 (coil spring) 22a1 to 22a4) is supported by the eccentric rotator 13 so as to be elastically movable. The eccentric rotator 13 is eccentrically rotated around the rotation axis of the output shaft 12b of the output rotator 12 by the centrifugal force of the weight 21 and the elastic force of the support device 22. It has a configuration like this. The strain element 23 presses the eccentric rotator 13 so as to start the eccentric orbiting motion described above or to accelerate and decelerate the eccentric orbiting motion. The output rotating body 12 is rotated by meshing the outer teeth 13b of the eccentric rotating body 13 and the inner teeth 12c of the output rotating body 12 by the eccentric rotating body 13 making an eccentric orbiting motion.

  As described above, even when the strain element 23 having a relatively small displacement amount is used, it is possible to apply the force necessary for the occurrence of the eccentric circular motion to the eccentric rotating body 13. Once the eccentric orbiting motion is started, a stable orbiting motion can be achieved by the pressing force by the strain element 23, the centrifugal force of the weight 21, and the elastic force by the support device 22. In addition, the eccentric rotating body 13 is not moved only by the pressing force by the strain element 23, but the eccentric rotating body 13 is moved eccentrically by using the elastic force of the support device 22 and the centrifugal force of the weight 21. The output rotating body 12 can be rotated.

  Therefore, a relatively large driving force can be obtained with a simple configuration. Furthermore, since the driving force has a good correlation with the centrifugal force of the weight 21, the driving force can be easily controlled by controlling the rotation (circulation) state of the weight 21.

  The support device 22 includes coil springs 22a1 to 22a4 (elastic members) interposed between the main body case 11 and the eccentric rotator 13, and supports the eccentric rotator 13 so as to be elastically movable with respect to the main body case 11. The strain element 23 is fixed to the main body case 11 and presses the eccentric rotator 13 by strain generated according to an electric signal. Accordingly, the eccentric rotator 13 can be reliably supported on the main body case 11 via the coil springs 22a1 to 22a4, and the eccentric rotator 13 can be reliably pressed by the strain element 23 fixed to the main body case 11. Can do.

  The strain element 23 is configured by any one of a piezoelectric element, a magnetostrictive element, an electrostrictive element, and a shape memory element. Thereby, the amount of distortion can be changed according to the supplied electric signal, and the rotation control of the eccentric rotating body 13 and the output control of the rotation driving device 10 can be easily performed.

  Further, a weight position detection sensor 14 for detecting the position of the weight 21 is further provided. Accordingly, the strain element 23 can be more reliably controlled by reliably detecting the position of the weight 21.

  Further, the strain element 23 is provided so as to press the eccentric rotator 13 in the tangential direction of the annular wall 13 d 1, whereby the energy of the strain element 23 can be effectively applied to the eccentric rotator 13 and thus the weight 21. It is possible to improve efficiency.

  In the embodiment described above, the output rotator 12 is provided with the internal teeth 12c and the eccentric rotator 13 is provided with the external teeth 13b meshing with the internal teeth 12c. In addition, the eccentric rotor 13 may be provided with internal teeth that mesh with the external teeth.

  Further, instead of or in place of supporting the output shaft 12b, the main body 12a (including the convex portion 12d) may be supported. Furthermore, the main body 13a of the eccentric rotator 13 may have a triangular shape or a circular shape instead of a square shape.

  Further, the rotary drive device 10 is not limited to be installed so that the orbital surface of the circular motion of the eccentric rotator 13 becomes a horizontal plane, and the rotary drive device 10 so that the orbital surface becomes a vertical surface. May be installed. In this case, when the rotary drive device 10 is stopped, the weight 21 is positioned at the lowest vertical direction of the annular groove 13d by its own weight, so that it is most efficiently pressed to raise the weight 21 from the lowermost part to the uppermost part at the time of activation. The strain element 23 should be disposed so as to be able to be taken into consideration (including the pressing direction).

2) Second Embodiment Next, a second embodiment will be described. While different points from the first embodiment will be described, the same components will be denoted by the same reference numerals and description thereof will be omitted. In the second embodiment, as shown in FIGS. 11 and 12, the support device 122 is different and the attachment position of the strain element 23 is different. 11 is a view of the inside from a certain cross section, and FIG. 12 is a cross sectional view taken along line 12-12 of FIG. In FIG. 12, only the base 111a is shown in the main body case 111, and other parts are omitted.

  The support device 122 includes a first support device 31 that is fixed to the body case 111 and can be elastically deformed, and coil springs 122a1 to 122a3 (elastic members) interposed between the first support device 31 and the eccentric rotating body 13. And a second support device 32 that supports the eccentric rotating body 13 with respect to the first support device 31 so as to be elastically movable.

  The main body case 111 is formed in a box shape from a metal material or a synthetic resin material. The main body case 111 has a base 111a arranged horizontally and a side wall 111b erected on the upper surface of the base 111a.

  The first support device 31 is formed of an elastic material (for example, a metal material or a synthetic resin material) so that the base end is fixed to the base 111 a of the main body case 111, the tip is a free end, and surrounds the eccentric rotating body 13. . The first support device 31 is an elongated plate-shaped material formed into a C shape. The plate-like material may be a metal material or a synthetic resin material as long as it is a material that is elastically deformed. The first support device 31 may not be C-shaped but may be U-shaped, and is preferably configured such that the bending increases toward the tip.

  Specifically, as shown in FIG. 12, the second support device 32 includes a plurality of (for example, three) coil springs 122 a 1, 122 a 2, and 122 a 3 for the main body 13 a of the eccentric rotating body 13. It supports from the direction (3 directions). Each coil spring 122a is interposed between the three corners of the main body 13a and the inner wall surface of the first support device 31 facing the corners. One end of each of the coil springs 122a1, 122a2, 122a3 is connected and fixed to each corner 13a1, 13a2, 13a3 of the main body 13a, and the other end is an inner wall surface of the first support device 31 and each corner 13a1 of the main body 13a. , 13a2 and 13a3 are connected and fixed at positions facing the inner wall surface of the first support device 31 at predetermined intervals. Further, the three coil springs 122a1, 122a2, 122a3 are set to the same length (natural length), and the spring constant is set to be smaller toward the tip of the first support device 31.

  As described above, the eccentric rotating body 13 is supported by the second support device 32 in a floating state. When the eccentric rotator 13 is not rotating (when the rotation driving device 10 is in a non-driven state), the center 13e of the eccentric rotator 13 is connected to the rotation axis of the output rotator 12 (output shaft 12a). It is designed to be supported to match.

  In the present embodiment, the center 13e of the eccentric rotating body 13 is the center of the external tooth 13b. In the present embodiment, the center of the outer tooth 13b and the center of the outer annular wall 13d1 are coincident, but may not be coincident if the center of the outer tooth 13b exists inside the outer annular wall 13d1. This is because the centrifugal force of the weight 21 can be used.

  The support device 122 is configured such that the amplitude of the first support device 31 increases as going to the tip of the first support device 31. Specifically, as described above, the first support device 31 may be configured such that the bending increases toward the tip. In addition, the spring constant of the coil spring 122a of the second support device 32 may be set smaller as it goes to the tip of the first support device 31 with the same length. In addition, you may make it set the coil spring 122a of the 2nd support apparatus 32 so that natural length may become long, so that it goes to the front-end | tip of the 1st support apparatus 31 with the same spring constant.

  The strain element 23 is attached to the proximal end portion of the first support device 31. When the tip of the strain element 23 swings counterclockwise in FIG. 12, the amplitude of the first support device 31 increases as the support device 122 goes to the tip of the first support device 31. The first support device 31 is deformed so as to shrink inward. On the other hand, when the tip of the strain element 23 swings clockwise in FIG. 12, the first support device 31 is deformed so as to expand outward. Note that the number of strain elements 23 may be not limited to one, but a plurality of strain elements 23 may be provided in the width direction. A larger force can be applied to the first support device 31. Further, a plurality of them may be provided in the longitudinal direction. A larger amplitude can be applied to the first support device 31.

  The side wall 111b is provided with a bearing 11b, and the output shaft 12b of the output rotation end 12 is rotatably supported on the bearing 11b.

  The operation of the rotary drive device 10 configured as described above will be described. When the distal end portion of the strain element 23 swings clockwise in FIG. 12, the first support device 31 is deformed so as to expand outward. The eccentric rotator 13 rotates in the clockwise direction around the corner 13a1 as a fulcrum. Along with this movement, the weight 21 moves in the clockwise direction.

  On the other hand, when the tip of the strain element 23 swings counterclockwise in FIG. 12, the first support device 31 is deformed so as to shrink inward. The eccentric rotating body 13 rotates counterclockwise around the corner 13a1 as a fulcrum. With this movement, the weight 21 moves in the counterclockwise direction.

  While repeating such a movement, the weight 21 starts a circular movement in the clockwise direction or the counterclockwise direction. During the eccentric orbiting motion of the eccentric rotator 13, the external teeth 13 b of the eccentric rotator 13 and the internal teeth 12 c of the output rotator 12 are engaged. Further, during the stable eccentric orbiting motion, the eccentric rotating body 13 and the weight 21 are performing the eccentric orbiting motion in synchronization with each other as in the first embodiment described above.

  Similar to the first embodiment, the output torque of the rotary drive device 10 can be adjusted by controlling the rotational speed of the weight 21. The rotational speed of the weight 21 can be controlled by controlling the vibration of the strain element 23.

  As is clear from the above description, in the rotary drive device 10 according to the first embodiment, the support device 122 includes the first support device 31 fixed to the body case 111 and elastically deformable, and the first support device. A second support device 32 comprising coil springs 122a1 to 122a3 (elastic members) interposed between 31 and the eccentric rotator 13, and supporting the eccentric rotator 13 with respect to the first support device 31 so as to be elastically movable; The strain element 23 is attached to the first support device 31 and vibrates the eccentric rotating body 13 by vibrating the first support device 31 by strain generated according to an electric signal. Accordingly, the eccentric rotator 13 is reliably supported on the main body case 111 via the second support device 32 formed of the coil springs 122a1 to 122a3 (elastic member) and the first support device 31 that can be elastically deformed, and the eccentric rotator. A relatively large vibration can be applied to 13. Further, since the strain element 23 directly vibrates the first support device 31 and the eccentric rotating body 13 is vibrated by the vibrated first support device 31, the eccentric rotation body 13 is more reliably vibrated by the strain element 23. be able to.

  In addition, the first support device 31 is formed of an elastic material so that the base end is fixed to the main body case 111 and the tip end is a free end and surrounds the eccentric rotating body 13, and the strain element 23 is the base end of the first support device 31. It is attached to the part. Thereby, the 1st support apparatus 31 can support the eccentric rotary body 13 by a simple structure so that elastic deformation is possible. Further, since the strain element 23 is attached to the proximal end portion of the first support device 31, the eccentric rotating body 13 can be vibrated efficiently.

  Further, the support device 122 is configured such that the amplitude of the first support device 31 increases as going to the tip of the first support device 31. Thereby, even if the vibration of the base end portion of the first support device 31 is small, a large amplitude can be ensured by going to the tip, so that the eccentric rotating body 13 can be vibrated more efficiently.

  Further, according to the second embodiment, the direction of the circular motion of the eccentric rotating body 13, that is, the direction of the circular motion of the weight 21 is controlled by changing the vibration speed of the strain element 23 in two different directions. be able to.

  Further, since the circular motion of the weight 21 occurs when the first support device 31 swings due to the vibration of the strain element 23, the rotation of the weight 21 can be started regardless of the position of the weight 21, and the rotation speed of the weight 21. Can be amplified.

  Further, by providing the first support device 31 with the second support device 32 constituted by the coil springs 122a1 to 122a3, the swing of the eccentric rotating body 13 can be increased, and the base end portion of the first support device 31 is provided. Even if the vibration is small, if it goes to the tip, a large amplitude can be secured, so that the rotation of the eccentric rotating body 13 and thus the weight 21 can be amplified without increasing the amplitude of the strain element 23.

  In addition, when a plurality of strain elements 23 are provided, vibrations applied to the first support device 31 can be controlled to different frequencies. That is, the rotational speed can be changed by changing the frequency, and the bending (amplitude) of the tip can be increased by vibrating the second support device 32 (support device 122) at different timings. The amount of eccentricity of the eccentric rotating body 13 can be increased.

  In the second embodiment, the rotary drive device 10 is installed so that the orbital surface of the circular motion of the eccentric rotator 13 is a vertical surface. In addition, you may make it install the rotational drive apparatus 10 so that the track surface may become a horizontal surface.

  Further, in the present embodiment, similarly to the first embodiment, the weight position detection sensor 14 may be provided, and the strain element 23 may be controlled by detecting the position of the weight 21. The three coil springs 122a1, 122a2, 122a3 may be set to the same length with the same spring constant.

  Moreover, although the present invention is applied to a rotary drive device having a hypocycloid gear, it may be applied to a rotary drive device having a planetary gear or another gear mechanism.

DESCRIPTION OF SYMBOLS 10 ... Rotary drive device, 11 ... Main body case, 12 ... Output rotary body, 12a ... Main body, 12b ... Output shaft, 12c ... Internal tooth, 12d ... Annular convex part, 13 ... Eccentric rotary body, 13a ... Main body, 13a1, 13a2 , 13a3 ... corners of the main body, 13b ... external teeth, 13c ... convex, 13d ... annular groove, 13d1 ... outer annular wall (annular wall), 13d2 ... inner annular wall, 13e ... center of the eccentric rotating body, 14 ... Weight position detection sensor, 20 ... eccentric motion generating device, 21 ... weight, 22 ... support device, 22a, 22a1, 22a2, 22a3, 22a4 ... coil spring, 23 ... strain element, 31 ... first support device, 32 ... second Support device, 111 ... body case, 111a ... base, 111b ... side wall, 122 ... support device, 122a1 to 122a3 ... coil spring.

Claims (8)

A body case,
An output rotating body that is rotatably supported by the main body case, includes an output shaft and an annular or internal teeth or outer teeth, and is rotated around a rotation axis of the output shaft;
The output rotating body eccentrically rotates with respect to the rotation axis of the output shaft, and the outer teeth of the output rotating body mesh with the internal teeth of the output rotating body when the eccentric rotating movement is performed. An eccentric rotator with internal teeth that mesh with the teeth;
A weight that abuts on the eccentric rotator along an annular wall formed around the rotation axis of the output shaft and circulates, a support device that supports the eccentric rotator so as to be elastically movable, and an electric signal A strain element that vibrates the eccentric rotator due to the strain generated by rotating the weight by the cooperation of the pressing force by the strain element, the elastic force by the support device, and the centrifugal force of the weight. An eccentric motion generating device that generates the eccentric orbiting motion in the eccentric rotating body. The support device according to claim 1, comprising an elastic member interposed between the main body case and the eccentric rotator, and supporting the eccentric rotator with respect to the main body case so as to be elastically movable.
The rotation drive device, wherein the strain element is fixed to the main body case and presses the eccentric rotating body by strain generated according to an electric signal. 2. The support device according to claim 1, wherein the support device includes a first support device fixed to the main body case and elastically deformable, and an elastic member interposed between the first support device and the eccentric rotating body. A second support device that supports the rotating body so as to be elastically movable with respect to the first support device;
The rotational driving device characterized in that the strain element is attached to the first support device and vibrates the eccentric rotating body by vibrating the first support device by strain generated according to an electric signal.   4. The rotation driving device according to claim 1, wherein the strain element is formed of any one of a piezoelectric element, a magnetostrictive element, an electrostrictive element, and a shape memory element. 5. .   5. The rotary drive device according to claim 1, further comprising a weight position detection sensor that detects a position of the weight. 6.   3. The rotation drive device according to claim 2, wherein the strain element is provided so as to press the eccentric rotating body in a tangential direction of the annular wall.   4. The first support device according to claim 3, wherein the first support device is formed of an elastic material so that a proximal end is fixed to the main body case, a distal end is a free end, and surrounds the eccentric rotating body, and the strain element is the first support device. It is attached to the base end of the rotary drive device. 8. The rotary drive device according to claim 7, wherein the support device is configured such that an amplitude of the first support device increases as going to a tip of the first support device.

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