JP2007170459A - Speed reducer with backlash eliminating function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speed reducer having a great reduction ratio for eliminating backlash while saving space. <P>SOLUTION: A drive unit 10 for a monitoring camera device 1 consists of a fixed first internal gear 15, a rotatable second internal gear 17, and two planetary paired gears 14 having a first external gear 26 and a second external gear 27 in a coaxial manner. The first external gear 26 of the planetary paired gears 14 gears with the first internal gear 15 and the second external gear 27 gears with the second internal gear 17. A reduction-ratio difference is given between the reduction ratio of the first internal gear 15 to the first external gear 26 and the reduction ratio of the second internal gear 17 to the second external gear 27. When rotation driving force is input to the planetary paired gears 14 to revolve while rotating, the rotation driving force is output with a speed reduced corresponding to the reduction ratio difference. At this time, the second internal gear 17 receives torsional stress from both sides toward a gear corresponding point between the first internal gear 15 and the second internal gear 17 to eliminate backlash. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reduction gear having a backlash removal function, and more particularly to a reduction gear with a backlash removal function used in a camera device.

  2. Description of the Related Art Conventionally, as a camera device, a monitoring camera device that performs monitoring using a surveillance camera that is installed on a wall or ceiling of a hallway or an elevator of a building is known. Such a monitoring camera device includes a motor for turning the monitoring camera, a reduction device for decelerating and transmitting the rotational driving force of the motor to the monitoring camera, and a backlash removal device for removing backlash. It has.

The conventional backlash removing device uses a torsion spring to bias a pair of gears in the opposite directions along the circumferential direction. The torsion spring is housed in an internal space formed when a pair of gears are combined in order to save space (see, for example, Patent Document 1).
Japanese Unexamined Patent Publication No. 2004-197822 (page 3-17, FIG. 1)

  However, the conventional backlash removing device can save space by accommodating the torsion spring in the internal space of the pair of gears, but has a problem that the assembling work of the torsion spring is not easy. Further, since the conventional reduction gear device of a camera device uses a multi-stage spur gear reduction device, it is necessary to increase the number of spur gears of the reduction device when obtaining a large reduction ratio. Therefore, there is a problem that it is difficult to save space by increasing the number of parts by that amount and increasing the size of the reduction gear. Moreover, what has a backlash removal function is not provided as a deceleration device used for a camera apparatus. Therefore, in the conventional camera device, it is necessary to separately provide a reduction gear and a backlash removal device, and there is a problem that the number of parts increases accordingly.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a speed reducer with a backlash removing function capable of obtaining a large reduction ratio and removing backlash.

  The reduction gear with backlash removal function of the present invention includes a first internal gear fixedly provided on a housing, and a second internal gear rotatably provided coaxially with the first internal gear. A plurality of satellite pair gears having a single external gear and a second external gear coaxially, wherein the first external gear of each satellite pair gear meshes with the first internal gear and the second external gear is the second gear. A plurality of satellite pair gears meshing with an internal gear and revolving while rotating along the first internal gear and the second internal gear, and a reduction ratio between the first internal gear and the first external gear; The reduction ratio between the second internal gear and the second external gear is provided with a reduction ratio difference. The satellite pair gears are revolved by the rotational driving force input from the drive source, and are decelerated according to the reduction ratio difference. The rotational driving force output from the second internal gear is In the gear, the first external gear and the second external gear has a configuration which is attached via a buffer member having elasticity.

  With this configuration, when the rotational driving force from the drive source is input to the satellite pair gear, the satellite pair gear revolves while rotating along the first internal gear and the second internal gear. At this time, a reduction ratio difference is provided between the reduction ratio of the first internal gear and the first external gear and the reduction ratio of the second internal gear and the second external gear. Therefore, when the satellite pair gear rotates while meshing with the first internal gear and the second internal gear, and makes one revolution along the first internal gear and the second internal gear, a large reduction ratio according to the reduction ratio difference is obtained. The rotational driving force is decelerated. Thereby, a large reduction ratio can be obtained on one rotating shaft. Accordingly, the number of parts does not increase and the size of the speed reducer does not increase as in the conventional multi-stage spur gear speed reducer, and space saving of the speed reducer can be achieved.

  Further, according to this configuration, when the first external gear and the second external gear of the satellite pair gear mesh with the first internal gear and the second internal gear and revolve while rotating, the first external gear and the second external gear. A slight twist occurs between the two. At this time, among the plurality of satellite pair gears, in the satellite pair gear located on one side from the gear coincidence point of the first internal gear and the second internal gear, the second internal gear is rotated toward the other side. Torsional stress is generated in the direction. Further, among the plurality of satellite pair gears, in the satellite pair gear located on the other side from the gear coincidence point of the first internal gear and the second internal gear, the direction in which the second internal gear is rotated toward one side. Torsional stress is generated. Therefore, the second internal gear receives torsional stress from both sides (one side and the other side) toward the gear coincidence point between the first internal gear and the second internal gear. Thereby, backlash is removed and the positional accuracy of the rotational position of the second internal gear is improved. Therefore, unlike the conventional case, there is no need to provide a backlash removing device separately from the speed reducer, the number of parts can be reduced, and space saving of the speed reducer can be achieved. Further, as compared with the conventional backlash device, it is not necessary to assemble the torsion spring, so that the assembling work is easy.

  In the speed reducer with a backlash removal function of the present invention, the number of teeth of the first internal gear and the number of teeth of the second internal gear are provided with a difference in the number of teeth.

  With this configuration, the reduction ratio is reduced to the reduction ratio between the first internal gear and the first external gear and the reduction ratio between the second internal gear and the second external gear according to the number of teeth difference between the first internal gear and the second internal gear. A ratio difference is provided. That is, when the satellite pair gear rotates while meshing with the first internal gear and the second internal gear, and makes one revolution along the first internal gear and the second internal gear, the first internal gear and the second internal gear The rotational position of is shifted by the difference in the number of teeth. Thereby, a reduction gear ratio difference is provided according to the number of teeth difference between the first internal gear and the second internal gear, and the rotational driving force is decelerated at a large reduction gear ratio according to the reduction gear ratio difference. For example, in this reduction means, the number of teeth of the first internal gear and the second internal gear is increased, and the difference in the number of teeth of the first internal gear and the second internal gear is reduced, so that a large reduction speed is achieved on one rotating shaft. A ratio can be obtained.

  In the speed reducer with a backlash removal function of the present invention, the first internal gear and the second internal gear have a configuration in which pitch circle diameters are different from each other.

  With this configuration, the pitch circle diameters of the first internal gear and the second internal gear are changed to provide a difference in the number of teeth between the number of teeth of the first internal gear and the number of teeth of the second internal gear. Thereby, a reduction gear ratio difference is provided according to the number of teeth difference between the first internal gear and the second internal gear, and the rotational driving force is decelerated at a large reduction gear ratio according to the reduction gear ratio difference. For example, by changing the pitch circle diameter of the first internal gear and the second internal gear, the number of teeth of the first internal gear and the second internal gear is increased, and the difference in the number of teeth of the first internal gear and the second internal gear is reduced. As a result, a large reduction ratio can be obtained on one rotating shaft.

  In the reduction gear with backlash removal function of the present invention, the first internal gear and the second internal gear have different configurations from each other.

  With this configuration, the module of the first internal gear and the second internal gear is changed to provide a difference in the number of teeth between the number of teeth of the first internal gear and the number of teeth of the second internal gear. Thereby, a reduction gear ratio difference is provided according to the number of teeth difference between the first internal gear and the second internal gear, and the rotational driving force is decelerated at a large reduction gear ratio according to the reduction gear ratio difference. For example, by changing the modules of the first internal gear and the second internal gear, increasing the number of teeth of the first internal gear and the second internal gear, and reducing the difference in the number of teeth of the first internal gear and the second internal gear A large reduction ratio can be obtained on one rotating shaft.

  In the speed reducer with backlash removal function of the present invention, the buffer member has a configuration made of an elastomer.

  With this configuration, the buffer member made of elastomer has a high effect of reducing vibration and noise, and a high effect of absorbing torsional stress. Here, the elastomer used as the material of the buffer member includes, for example, thermoplastic elastomer, vulcanized rubber, elastic foam, elastic fiber, and the like.

  In the reduction device with a backlash removal function of the present invention, the reduction device includes an input unit that rotates about the rotation shafts of the first internal gear and the second internal gear and revolves the satellite pair gears. Has a configuration in which a through hole is formed along the rotation axis direction of the first internal gear and the second internal gear.

  With this configuration, the wiring is passed through the through hole of the input means formed along the rotation axis direction of the first internal gear and the second internal gear. Thereby, compared with the case where a through-hole is formed in another location, a space can be used effectively and space saving can be achieved.

  The camera device of the present invention includes the above-described reduction device with a backlash removal function, a drive source connected to the reduction device with the backlash removal function, and the reduction device with the backlash removal function by a driving force from the drive source. And a camera that is rotated via the camera.

  In the present invention, a large reduction ratio is obtained and backlash is reduced by providing a reduction ratio difference between the reduction ratio of the first internal gear and the first external gear and the reduction ratio of the second internal gear and the second external gear. It is possible to provide a speed reducer with a backlash removing function that can be removed and can save space.

  Hereinafter, a reduction gear with a backlash removal function according to an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a case of a reduction gear with a backlash removal function used for a monitoring camera device or the like is illustrated.

(This embodiment)
FIG. 2 shows a monitoring camera device provided with the reduction gear according to the embodiment of the present invention. The monitoring camera device 1 is a dome-type monitoring camera device 1 that is installed on a wall or ceiling of a hallway or an elevator of a building and performs monitoring using a turning camera 4. As shown in FIG. 2, the monitoring camera device 1 includes a base 2 fixed to a wall, a ceiling, and the like, an L-shaped frame 3 that is mounted on the base 2 so as to be rotatable left and right, and an L-shaped frame 3 that is turned up and down. The camera 4 is movably mounted, and is entirely covered with a transparent dome cover 5.

  FIG. 3 is a perspective view showing a state in which the camera 4 is attached to the L-shaped frame 3, and FIG. 4 is an exploded perspective view thereof. As shown in FIGS. 3 and 4, the L-shaped frame 3 includes a vertical frame 6 and a horizontal frame 7. A central fitting hole 8 is formed at the center of the vertical frame 6 and the horizontal frame 7, and a motor mounting hole 9 is formed beside the central fitting hole 8 of the vertical frame 6 and the horizontal frame 7. Yes.

  A tilt drive unit 10 a is attached to the vertical frame 6 of the L-shaped frame 3, and a pan drive unit 10 b is attached to the horizontal frame 7. The camera 4 is attached to the tilt drive unit 10a via the camera holding frame 11, and the base 2 is attached to the pan drive unit 10b (see FIG. 2).

  In the present embodiment, a common drive unit 10 is used as the tilt drive unit 10a and the pan drive unit 10b. That is, the drive unit for tilt 10a and the drive unit for pan 10b have the same configuration. Here, the configuration of the common drive unit 10 will be described below.

  FIG. 5 is a partial cross-sectional view of the drive unit 10 (for example, the drive unit 10a for tilting) attached to the L-shaped frame 3. As shown in FIGS. 4 and 5, the drive unit 10 includes a motor 12, an input gear 13 to which a rotational driving force from the motor 12 is input, a satellite pair gear 14 attached to the input gear 13, and a first internal gear. A unit frame 16 having a gear 15, an output member 18 having a second internal gear 17, and a unit cover 19 attached to the unit frame 16 are provided.

  As shown in FIGS. 2 to 5, from the outside (left side in FIGS. 2 and 5) of the vertical frame 6 of the L-shaped frame 3, a motor 12 (for example, a tilting motor) is inserted into the motor mounting hole 9 of the vertical frame 6. 12) is attached. The input gear 13 is attached to the center fitting hole 8 of the vertical frame 6 from the inside of the vertical frame 6 (the right side in FIGS. 2 and 5). Here, the motor 12 corresponds to a drive source of the present invention.

  As shown in FIGS. 2 to 5, the input gear 13 meshes with a drive gear 21 attached to a motor rotation shaft 20 of a motor 12 (for example, a tilting motor 12). In addition, a cylindrical fitting boss portion 22 is erected outward at the center of the outer side surface (left side surface in FIGS. 2 and 5) of the input gear 13. The input gear 13 is rotatably attached to the vertical frame 6 by fitting the fitting boss portion 22 of the input gear 13 into the center fitting hole 8 of the vertical frame 6. In addition, a cylindrical sun boss portion 23 (corresponding to the sun portion for the satellite pair gear 14) is erected inward at the center of the inner surface of the input gear 13 (the right side in FIGS. 2 and 5). In the vicinity of the sun boss portion 23 on the inner surface of the input gear 13, two rotation shafts 24 (corresponding to the satellite rotation shaft for the satellite pair gear 14) are erected inward. The input gear 13 rotates around the rotation axes of the first internal gear 15 and the second internal gear 17. Further, a through hole 25 is formed in the central portion of the input gear 13 along the rotation axis direction of the first internal gear 15 and the second internal gear 17 (see FIG. 1). Here, the input gear 13 corresponds to the input means of the present invention, and the through hole 25 of the input gear 13 corresponds to the through hole of the present invention.

  Two satellite pair gears 14 are rotatably fitted to the two rotation shafts 24 of the input gear 13. FIG. 6 is an exploded perspective view of the satellite pair gear 14, and FIG. 7 is a cross-sectional view of the satellite pair gear 14. 6 and 7, the satellite pair gear 14 includes a first external gear 26 that meshes with the first internal gear 15, a second external gear 27 that is arranged coaxially with the first external gear 26, and an input. The buffer member 28 is fitted to the rotation shaft 24 of the gear 13. The buffer member 28 is in the shape of a cross with a hole in which a rotation shaft hole 29 for inserting the rotation shaft 24 is provided at the center and a convex portion 30 is provided in all directions. Cross-shaped fitting holes 31 and 32 corresponding to the shape of the buffer member 28 are provided in the central portions of the first external gear 26 and the second external gear 27, respectively. The first external gear 26 and the second external gear 27 are respectively fitted on the buffer member 28 and arranged coaxially. It can also be said that the first external gear 26 and the second external gear 27 are attached to the rotation shaft 24 via the buffer member 28.

  As a material of the buffer member 28, for example, an elastomer such as a thermoplastic elastomer, a vulcanized rubber, an elastic foam, and an elastic fiber is used alone or in combination. As a material of the buffer member 28 of the present embodiment, it is preferable to use a thermoplastic elastomer.

  FIG. 1 is a plan view showing a state in which two satellite pair gears 14 are attached to the input gear 13. As shown in FIG. 1, the two satellite pair gears 14 are attached at positions close to each other (in FIG. 1, a position about 20 ° apart from the central angle). As shown in FIGS. 1 and 5, the satellite pair gear 14 is attached to the rotation shaft 24 of the input gear 13, and the first external gear 26 meshes with the first internal gear 15 and the second external gear. 27 meshes with the second internal gear 17. Then, when the input gear 13 rotates, the satellite pair gear 14 rotates while the first external gear 26 meshes with the first internal gear 15 and the second external gear 27 meshes with the second internal gear 17 and rotates. It is configured to revolve around the sun boss portion 23 along the circumferential direction of the first internal gear 15 and the second internal gear 17.

  At this time, a slight twist is generated between the first external gear 26 and the second external gear 27 of the satellite pair gear 14. In the present embodiment, of the two satellite pair gears 14, one side (the right side in FIG. 1) of the first internal gear 15 and the second internal gear 17 from the gear coincidence point (the position at 12 o'clock in FIG. 1). ), The torsional stress is generated in such a direction as to rotate the second internal gear 17 toward the other side (left side in FIG. 1). Of the two satellite pair gears 14, the satellite pair gear 14 located on the other side of the gear coincidence point of the first internal gear 15 and the second internal gear 17 rotates the second internal gear 17 toward one side. The torsional stress is generated in such a direction. That is, the second internal gear 17 receives a torsional stress from both sides (one side and the other side) toward the gear coincidence point between the first internal gear 15 and the second internal gear 17. Therefore, regardless of whether the second internal gear 17 (output member 18) rotates in the forward or reverse direction, the second internal gear 17 (output member 18) receives torsional stress from both sides and is positioned at the gear coincidence point. Become. Thereby, in the drive unit 10 of this Embodiment, the backlash is removed. Therefore, it can be said that the drive unit 10 of the present embodiment is a drive unit 10 with a backlash removal function.

  As shown in FIGS. 2 to 5, a unit frame 16 is attached from the inside of the input gear 13 to the inner side surface (the right side surface in FIGS. 2 and 5) of the vertical frame 6 of the L-shaped frame 3. A circular central opening 33 is formed at the center of the unit frame 16. A first internal gear 15 is formed on the inner peripheral surface of the peripheral edge of the central opening 33 of the unit frame 16. As shown in FIG. 4, a motor mounting portion 34 is provided at the lower portion of the unit frame 16. The tilt motor 12 is attached to the motor attachment portion 34 of the unit frame 16 through the motor attachment hole 9 of the vertical frame 6. Here, the unit frame 16 corresponds to the housing of the present invention.

  An output member 18 is mounted coaxially with the input gear 13 inside the input gear 13 and the satellite pair gear 14. As shown in FIGS. 1 and 5, a through hole 35 is formed at the center of the output member 18, and a fitting annular step is provided at the peripheral edge of the upper end of the through hole 35 of the output member 18. A portion 36 is formed. Then, the output member 18 and the input gear 13 are rotatable with respect to each other by fitting the lower end portion of the sun boss portion 23 of the input gear 13 into the fitting annular step portion 36 of the output member 18. A second internal gear 17 that meshes with the second external gear 27 of the satellite pair gear 14 is formed on the outer side surface (left side surface in FIG. 5) of the output member 18.

  In the present embodiment, as shown in FIG. 5, a first annular step portion 37 is formed on the outer side surface (left side surface in FIG. 5) of the peripheral edge of the central opening 33 of the unit frame 16. The input gear 13 is housed in the first annular step 37 with the unit frame 16 attached to the vertical frame 6. In this way, the input gear 13 is rotatably attached to the unit frame 16. On the other hand, a second annular step 38 is formed on the inner side surface (the right side surface in FIG. 5) of the peripheral edge of the central opening 33 of the unit frame 16. A mounting annular step 39 is provided on the upper surface of the unit cover 19. The unit cover 19 is attached to the unit frame 16 in a state where the output member 18 is stored in the mounting annular step portion 39 of the unit cover 19, and the output member 18 is stored in the second annular step portion 38 of the unit frame 16. In this way, the output member 18 is rotatably attached to the unit frame 16.

  As shown in FIGS. 2 and 4, a rotating member 41 is attached and fixed to the output member 18 of the tilt drive unit 10 a via an attachment plate 40. An L-shaped camera holding frame 11 is attached and fixed to the rotating member 41. A camera mounting hole 42 is provided in the camera holding frame 11, and a camera 4 using an image sensor such as a CCD or CMOS is mounted in the camera mounting hole 42. On the other hand, the base 2 is attached and fixed to the rotating member 41 attached to the drive unit 10b for bread.

  In the present embodiment, the module m1 of the first internal gear 15 is set to 0.4 mm, the pitch circle diameter d1 is set to 35.2 mm, and the number of teeth z1 is set to 88. The module m2 of the second internal gear 17 is set to 0.4 mm, the pitch circle diameter d2 is set to 34.8 mm, and the number of teeth z2 is set to 87. Here, the module m3 of the first external gear 26 of the satellite pair gear 14 is set to 0.4 mm, the pitch circle diameter d3 is set to 7.6 mm, and the number of teeth z3 is set to 19. . The module m4 of the second external gear 27 is set to 0.4 mm, the pitch circle diameter d4 is set to 7.2 mm, and the number of teeth z4 is set to 18.

As described above, in the present embodiment, the first internal gear 15 and the second internal gear 17 are set to different values by setting the pitch circle diameters d1 and d2 of the first internal gear 15 and the second internal gear 17 to different values. A tooth number difference Δz is provided, and the speed reduction ratio is reduced to the reduction ratio between the first internal gear 15 and the first external gear 26 and the reduction ratio between the second internal gear 17 and the second external gear 27 according to the tooth number difference Δz. A ratio difference is provided. In this case, a large reduction ratio i corresponding to the reduction ratio difference is expressed by the following Equation 1.
Reduction ratio i = {z4 × (z1 / z3) −z2} / z2 (Formula 1)

  As described above, since the reduction ratio difference is provided between the reduction ratio of the first internal gear 15 and the first external gear 26 and the reduction ratio of the second internal gear 17 and the second external gear 27, the satellite pair gears. 14 rotates around the first internal gear 15 and the second internal gear 17 and revolves around the sun boss portion 23 along the first internal gear 15 and the second internal gear 17. The rotational positions of the internal gear 15 and the second internal gear 17 are shifted by the reduction ratio difference. As a result, the rotational driving force is decelerated at a large reduction ratio i (≈0.0417) corresponding to the reduction ratio difference. Therefore, it can be said that the drive unit 10 of the present embodiment is a drive unit 10 with a large deceleration function. Here, the drive unit 10 with a large deceleration function corresponds to the reduction gear of the present invention.

  Further, in the present embodiment, as shown in FIGS. 1 and 5, the central portion of the input gear 13 and the output member 18 (second internal gear 17) is along the rotation axis direction (the vertical direction in the drawing in FIG. 1). The through holes 25 and 35 are provided. In the present embodiment, the outer surface of the first external gear 26 of the satellite pair gear 14 contacts the inner surface of the input gear 13 and rotates while sliding smoothly. Further, the inner side surface of the second external gear 27 of the satellite pair gear 14 is in contact with the outer side surface of the output member 18 and rotates while sliding smoothly. That is, the satellite pair gear 14 is sandwiched between the input gear 13 and the output member 18 so as to be slidable and rotatable.

  The operation of the dome-type surveillance camera device 1 having the drive unit 10 (the speed reduction device with a backlash removal function) configured as described above will be described below.

  When the surveillance camera device 1 according to the embodiment of the present invention is turned up and down (tilted), the tilt motor 12 is driven using a controller (not shown). The rotational driving force of the motor 12 is transmitted from the driving gear 21 attached to the motor rotating shaft 20 to the input gear 13, and the input gear 13 rotates.

  When the input gear 13 rotates, the satellite pair gear 14 revolves around the sun boss portion 23 along the first internal gear 15 and the second internal gear 17. At this time, the first external gear 26 of the satellite pair gear 14 meshes with the first internal gear 15 and the second external gear 27 meshes with the second internal gear 17, so that the satellite pair gear 14 revolves while rotating. In the present embodiment, the first internal gear 15 and the second internal gear 17 are provided with a tooth number difference Δz, and the reduction ratio between the first internal gear 15 and the first external gear 26 is determined according to the tooth number difference Δz. The reduction ratio between the second internal gear 17 and the second external gear 27 is provided with a reduction ratio difference. Therefore, when the satellite pair gear 14 revolves around the sun boss portion 23 once, the second internal gear 17 that is rotatable with respect to the fixed first internal gear 15 rotates slightly behind, and the first The relative rotational positions of the internal gear 15 and the second internal gear 17 are shifted by the difference in reduction ratio. In this manner, when the rotational driving force is transmitted from the input gear 13 to the second internal gear 17, the speed is reduced at a large reduction ratio i corresponding to the reduction ratio difference, and the rotation direction is reversed.

  The rotational driving force decelerated and transmitted to the second internal gear 17 is output from the output member 18 provided integrally with the second internal gear 17 to the camera holding frame 11 via the rotary member 41. When the camera holding frame 11 rotates, the camera holding frame 11 rotates up and down with respect to the L-shaped frame 3 together with the camera 4, and the camera 4 of the monitoring camera device 1 rotates up and down (tilt). .

  When the monitoring camera device 1 of the present embodiment is rotated left and right (panned), a panning motor 12 is driven using a controller (not shown). Then, in the same manner as described above, the rotational driving force of the motor 12 is transmitted from the driving gear 21 attached to the motor rotating shaft 20 to the input gear 13 and the input gear 13 rotates.

  When the input gear 13 rotates, the satellite pair gear 14 revolves along the first internal gear 15 and the second internal gear 17 while rotating around the sun boss portion 23. Similarly to the above case, when the satellite pair gear 14 revolves around the sun boss portion 23 once, the relative rotational positions of the first internal gear 15 and the second internal gear 17 are as described above. It shifts by the reduction ratio difference. In this manner, when the rotational driving force is transmitted from the input gear 13 to the second internal gear 17, the speed is reduced at a large reduction ratio i corresponding to the reduction ratio difference, and the rotation direction is reversed.

  The rotational driving force transmitted by decelerating to the second internal gear 17 is output from the output member 18 provided integrally with the second internal gear 17 to the base 2. Then, the base 2 tries to turn left and right with respect to the L-shaped frame 3. In this case, since the base 2 is fixed to a ceiling, a wall surface or the like, when the base 2 tries to turn left and right with respect to the L-shaped frame 3, the L-shaped frame 3 rotates left and right with respect to the base 2 by the reaction force. Move. When the L-shaped frame 3 rotates left and right with respect to the base 2, the camera 4 attached to the L-shaped frame 3 via the camera holding frame 11 also rotates with respect to the base 2 in the left-right direction. In this way, the camera 4 of the monitoring camera device 1 rotates left and right (panning).

  According to the drive unit 10 of such an embodiment of the present invention, the reduction ratio between the first internal gear 15 and the first external gear 26 and the reduction ratio between the second internal gear 17 and the second external gear 27 are reduced. By providing the difference, it is possible to obtain a large reduction ratio i corresponding to the reduction ratio difference, to eliminate backlash, and to save space.

  That is, in the drive unit 10 of the present embodiment, when the rotational driving force from the motor 12 is input to the satellite pair gear 14, the satellite pair gear 14 rotates along the first internal gear 15 and the second internal gear 17. While revolving. At this time, a reduction ratio difference is provided between the reduction ratio of the first internal gear 15 and the first external gear 26 and the reduction ratio of the second internal gear 17 and the second external gear 27. Therefore, when the satellite pair gear 14 rotates while meshing with the first internal gear 15 and the second internal gear 17 and makes one revolution along the first internal gear 15 and the second internal gear 17, the reduction ratio difference is increased. The rotational driving force is decelerated at a corresponding large reduction ratio i. Thereby, a large reduction ratio i can be obtained on one rotating shaft. Therefore, the number of parts does not increase and the size of the speed reducer does not increase as in the conventional multi-stage spur gear speed reducer, and space saving of the speed reducer can be achieved.

  Further, in the drive unit 10 of the present embodiment, the first external gear 26 and the second external gear 27 of the satellite pair gear 14 mesh with the first internal gear 15 and the second internal gear 17 having the tooth number difference Δz. When revolving while rotating, a slight twist occurs between the first external gear 26 and the second external gear 27. At this time, of the two satellite pair gears 14, in the satellite pair gear 14 located on one side from the gear coincidence point of the first internal gear 15 and the second internal gear 17, the second internal gear 17 is directed to the other side. Torsional stress is generated in such a direction as to rotate. Of the two satellite pair gears 14, the satellite pair gear 14 located on the other side of the gear coincidence point of the first internal gear 15 and the second internal gear 17 rotates the second internal gear 17 toward one side. Torsional stress is generated in such a direction. Therefore, the second internal gear 17 receives torsional stress from both sides (one side and the other side) toward the gear coincidence point between the first internal gear 15 and the second internal gear 17. Thereby, the backlash is removed and the positional accuracy of the rotational position of the second internal gear 17 is improved. Therefore, unlike the conventional case, there is no need to provide a backlash removing device separately from the speed reducer, the number of parts can be reduced, and space saving of the speed reducer can be achieved. Further, as compared with the conventional backlash device, it is not necessary to assemble the torsion spring, and the same operation of assembling the satellite pair gear 14 can be performed twice, so that the assembling operation is easy.

  In the drive unit 10 of the present embodiment, since the elastic buffer member 28 is interposed between the first external gear 26 and the second external gear 27, the first external gear 26 and the second external gear. 27 is absorbed by the buffer member 28. Thereby, the rotation and revolution of the satellite pair gear 14 are performed smoothly. In addition, since the elastic buffer member 28 is interposed between the first external gear 26 and the second external gear 27, vibration transmitted from the drive source to the first external gear 26 is absorbed by the buffer member 28. . Thereby, the vibration transmitted to the second external gear 27 is reduced, and the noise generated by the vibration is reduced.

  Further, in the drive unit 10 of the present embodiment, the reduction ratio between the first internal gear 15 and the first external gear 26, the second internal gear 15, and the second external gear 26 according to the tooth number difference Δz between the first internal gear 15 and the second internal gear 17. A reduction ratio difference is provided in the reduction ratio between the internal gear 17 and the second external gear 27. That is, when the satellite pair gear 14 rotates while meshing with the first internal gear 15 and the second internal gear 17, and makes one revolution along the first internal gear 15 and the second internal gear 17, the first internal gear 15 and the rotation position of the second internal gear 17 are shifted by an amount corresponding to the tooth number difference Δz. Thereby, a reduction gear ratio difference is provided according to the tooth number difference Δz between the first internal gear 15 and the second internal gear 17, and the rotational driving force is decelerated at a large reduction gear ratio i corresponding to the reduction gear ratio difference. For example, in the drive unit 10, the number of teeth of the first internal gear 15 and the second internal gear 17 is increased, and the tooth number difference Δz between the first internal gear 15 and the second internal gear 17 is reduced to reduce the number of teeth. A large reduction ratio i can be obtained on the rotation axis. Therefore, the number of parts does not increase and the size of the speed reduction mechanism does not increase as in the conventional case, and the monitoring camera device 1 can be downsized.

  Further, in the drive unit 10 of the present embodiment, the number of teeth z1 of the first internal gear and the number of teeth of the second internal gear are changed by changing the pitch circle diameters d1 and d2 of the first internal gear 15 and the second internal gear 17. A tooth number difference Δz is provided for z2. Thereby, a reduction gear ratio difference is provided according to the tooth number difference Δz between the first internal gear 15 and the second internal gear 17, and the rotational driving force is decelerated at a large reduction gear ratio i corresponding to the reduction gear ratio difference. For example, the pitch circle diameters d1 and d2 of the first internal gear 15 and the second internal gear 17 are changed to increase the number of teeth z1 and z2 of the first internal gear 15 and the second internal gear 17, and the first internal gear 15 By reducing the tooth number difference Δz of the second internal gear 17, a large reduction ratio i can be obtained on one rotating shaft.

  In the drive unit 10 of the present embodiment, an elastomeric buffer member 28 is used. The buffer member 28 made of elastomer has a high effect of reducing vibration and noise, and a high effect of absorbing torsional stress.

  In the drive unit 10 of the present embodiment, the wiring of the camera 4 is passed through the through holes 25 and 35 of the input gear 13 and the output member 18 (second internal gear 17). Thereby, compared with the case where a through-hole is formed in another part of the L-shaped frame 3 of the monitoring camera device 1, the space inside the monitoring camera device 1 can be used effectively, and space saving is achieved. Can be achieved. Therefore, the monitoring camera device 1 can be reduced in size.

  Further, in the drive unit 10 of the present embodiment, by setting the number of teeth z2 of the second internal gear 17 to be smaller than the number of teeth z1 of the first internal gear 15, the rotational direction of the input gear 13 and the output member 18 The direction of rotation can be reversed. Conventionally, in order to reverse the rotation direction of the gear, it has been necessary to interpose another member such as an idler gear, but in the present embodiment, the gear of the gear is not interposed without interposing another member such as an idler gear. The direction of rotation can be reversed. Thereby, space saving can be achieved by the amount of another member such as an idler gear, and the monitoring camera device 1 can be miniaturized.

  As described above, in the monitoring camera device 1 including the drive unit 10 of the present embodiment, the monitoring camera device 1 can be downsized.

(Modification)
A modification of the present embodiment is shown in FIG. FIG. 8 is a sectional view of a speed reduction mechanism according to a modification. The configuration of this modified example is the same as the configuration of the above embodiment, although the set value of the gear of the speed reduction mechanism is different from that of the above embodiment.

  In this modification, the module m1 of the first internal gear 15 is set to 0.4 mm, the pitch circle diameter d1 is set to 34.8 mm, and the number of teeth z1 is set to 87. The module m2 of the second internal gear 17 is set to 0.395 mm, the pitch circle diameter d2 is set to 34.8 mm, and the number of teeth z2 is set to 88. Here, the module m3 of the first external gear 26 of the satellite pair gear 14 is set to 0.4 mm, the pitch circle diameter d3 is set to 7.2 mm, and the number of teeth z3 is set to 18. . The module m4 of the second external gear 27 is set to 0.4 mm, the pitch circle diameter d4 is set to 7.2 mm, and the number of teeth z4 is set to 18.

  As described above, in this modification, by setting the modules m1 and m2 of the first internal gear 15 and the second internal gear 17 to different values, the first internal gear 15 and the second internal gear 17 have a difference in the number of teeth. Δz is provided, and the reduction ratio difference between the reduction ratio of the first internal gear 15 and the first external gear 26 and the reduction ratio of the second internal gear 17 and the second external gear 27 depends on the difference in the number of teeth Δz. Is provided.

  In this modification, the difference between the module m2 of the second internal gear 17 and the module m4 of the second external gear 27 is very small. On the other hand, a slight clearance is provided between the second internal gear 17 and the second external gear 27. Therefore, although the module m2 of the second internal gear 17 and the module m4 of the second external gear 27 are different, there is a margin corresponding to the clearance between the second internal gear 17 and the second external gear 27. 17 and the second external gear 27 can mesh with each other.

  In this modification, the modules m1 and m2 of the first internal gear 15 and the second internal gear 17 are changed so that the number of teeth difference Δz between the number of teeth z1 of the first internal gear 15 and the number of teeth z2 of the second internal gear 17 varies. Provided. Thereby, a reduction gear ratio difference is provided according to the tooth number difference Δz between the first internal gear 15 and the second internal gear 17, and the rotational driving force is decelerated at a large reduction gear ratio i corresponding to the reduction gear ratio difference. For example, the modules m1 and m2 of the first internal gear 15 and the second internal gear 17 are changed to increase the number of teeth z1 and z2 of the first internal gear 15 and the second internal gear 17, and the first internal gear 15 and the second internal gear 17 2 The tooth number difference Δz of the internal gear 17 is reduced. Thereby, a large reduction ratio i can be obtained on one rotating shaft. Therefore, the number of parts does not increase and the size of the speed reduction mechanism does not increase as in the conventional case, and the monitoring camera device 1 can be downsized.

  In this case, when the satellite pair gear 14 revolves around the sun boss portion 23 once, the second internal gear 17 that is rotatable with respect to the fixed first internal gear 15 slightly advances and rotates, The relative rotational positions of the first internal gear 15 and the second internal gear 17 are shifted by the difference in reduction ratio. In this way, when the rotational driving force is transmitted from the input gear 13 to the second internal gear 17, the speed is reduced at a large speed reduction ratio i corresponding to the speed reduction ratio difference. At this time, the rotation direction of the input gear 13 and the rotation direction of the output member 18 are the same rotation direction.

  As another modification, the number of teeth z1 and z2 of the above modification may be reversed. That is, the module m1 of the first internal gear 15 is set to 0.395 mm, the pitch circle diameter d1 is set to 34.8 mm, the number of teeth z1 is set to 88, and the module of the second internal gear 17 is set. m2 may be set to 0.4 mm, the pitch circle diameter d2 may be set to 34.8 mm, and the number of teeth z2 may be set to 87. In this case, the rotation direction of the input gear 13 and the rotation direction of the output member 18 are opposite to each other.

  As still another modification, the number of teeth z1 and z2 of the present embodiment may be reversed. That is, the module m1 of the first internal gear 15 is set to 0.4 mm, the pitch circle diameter d1 is set to 34.8 mm, the number of teeth z1 is set to 87, and the module of the second internal gear 17 is set. m2 may be set to 0.4 mm, the pitch circle diameter d2 may be set to 35.2 mm, and the number of teeth z2 may be set to 88. In this case, the rotation direction of the input gear 13 and the rotation direction of the output member 18144 are the same rotation direction.

  The embodiments of the present invention have been described above by way of example, but the scope of the present invention is not limited to these embodiments, and can be changed or modified according to the purpose within the scope of the claims. is there.

  For example, in the above description, an example of a speed reducer with a backlash removal function provided with two satellite pair gears 14 has been described. However, the scope of the present invention is not limited to these, and three or more satellite pairs are provided. A reduction gear with a backlash removing function including the gear 14 may be used.

  In the above description, in order to provide a reduction ratio difference between the reduction ratio of the first internal gear and the first external gear and the reduction ratio of the second internal gear and the second external gear, The case where the number of teeth difference Δz is provided in the number of teeth z1 and z2 of the internal gear is illustrated. However, the scope of the present invention is not limited to this, and a reduction ratio difference is provided between the reduction ratio of the first internal gear and the first external gear and the reduction ratio of the second internal gear and the second external gear. It may be the structure which is. For example, the tooth number difference Δz is not provided in the tooth numbers z1 and z2 of the first internal gear and the second internal gear, and the tooth number difference is provided in the tooth numbers z3 and z4 of the first external gear and the second external gear. It may be done.

  In the above description, the first internal gear 15 and the first internal gear 15 and the second internal gear 17 are set differently from each other by setting either the modules m1 and m2 or the pitch circle diameters d1 and d2 of the second internal gear 17 to be different from each other. The example in which the number of teeth z1 and z2 of the internal gear 17 is different from each other has been described. However, the scope of the present invention is not limited to these, and by setting both the modules m1 and m2 and the pitch circle diameters d1 and d2 of the first internal gear 15 and the second internal gear 17 to be different from each other. The number of teeth z1 and z2 of the first internal gear 15 and the second internal gear 17 may be different from each other.

  In the above description, the case where the tooth number difference Δz between the first internal gear 15 and the second internal gear 17 is 1 has been described, but the scope of the present invention is not limited to these, and the first internal gear 15 The tooth number difference Δz between the gear 15 and the second internal gear 17 may be two or more.

  As described above, the speed reduction device with a backlash function according to the present invention has an effect that a large reduction ratio can be obtained and the backlash can be removed, and space saving can be achieved. It is useful as a reduction gear used in

The figure which shows a mode that two satellite pair gears were attached to the input gear in the drive unit of embodiment of this invention. The front view for demonstrating the dome type surveillance camera apparatus in embodiment of this invention The perspective view which shows the state which attached the camera in embodiment of this invention to the L-shaped flame | frame. The disassembled perspective view which shows a mode that the drive unit in embodiment of this invention is attached to an L-shaped frame Sectional drawing of the drive unit attached to the L-shaped frame in embodiment of this invention 1 is an exploded perspective view of a satellite pair gear according to an embodiment of the present invention. Sectional view of the satellite pair gear in the embodiment of the present invention Sectional drawing of the satellite pair gear in the modification of embodiment of this invention

Explanation of symbols

1 Surveillance camera device 4 Camera 10 Drive unit (decelerator with backlash removal function)
12 Motor (drive source)
13 Input gear (input means)
14 Satellite pair gear 15 First internal gear 16 Unit frame (housing)
17 Second internal gear 18 Output member 25 Input gear through hole 26 First external gear 27 Second external gear 28 Buffer member 35 Output member through hole

Claims (7)

A first internal gear fixedly provided on the housing;
A second internal gear rotatably provided coaxially with the first internal gear;
A plurality of satellite pair gears each having a first external gear and a second external gear coaxially, wherein the first external gear of each satellite pair gear meshes with the first internal gear, and the second external gear is A plurality of satellite pair gears meshing with the second internal gear and revolving while rotating along the first internal gear and the second internal gear;
With
A reduction ratio difference is provided between the reduction ratio of the first internal gear and the first external gear and the reduction ratio of the second internal gear and the second external gear.
The satellite pair gears revolve by the rotational driving force input from the driving source, and the rotational driving force decelerated according to the reduction ratio difference is output from the second internal gear.
In each satellite pair gear, the first external gear and the second external gear are attached via a buffer member having elasticity, and a reduction device with a backlash removal function.   2. The reduction device with a backlash removal function according to claim 1, wherein a difference in the number of teeth is provided between the number of teeth of the first internal gear and the number of teeth of the second internal gear.   The speed reduction device with a backlash removal function according to claim 2, wherein the first internal gear and the second internal gear have different pitch circle diameters.   The speed reduction device with a backlash removal function according to claim 2, wherein the first internal gear and the second internal gear have different modules.   The speed reducing device with a backlash removing function according to any one of claims 1 to 4, wherein the buffer member is made of an elastomer. An input means for rotating about the rotation axis of the first internal gear and the second internal gear and revolving the satellite pair gear;
The through hole is formed in the said input means along the rotating shaft direction of the said 1st internal gear and the said 2nd internal gear, The Claim 1 thru | or 5 characterized by the above-mentioned. Reducer with backlash removal function. A speed reducer with a backlash removal function according to any one of claims 1 to 6,
A drive source connected to the speed reducer with backlash removal function;
A camera that is rotated by the driving force from the driving source via the reduction device with the backlash removing function;
A camera device comprising:

Images