KR20190106795A - Transmission device - Google Patents

Abstract

According to an embodiment of the present invention, a transmission device comprises: a first gear connected to a drive source; a ring gear having an outer circumferential surface provided with an outer tooth engaged with the first gear and an inner circumferential surface provided with an inner tooth; a second gear engaged with the inner tooth of the ring gear; a deceleration unit decelerating and outputting an input from the second gear; and a bearing arranged at an internal side in a diameter direction of the ring gear compared to the inner tooth, and rotationally supporting the ring gear.

Description

Delivery device {TRANSMISSION DEVICE}

The present invention relates to a transmission device (eg, a speed reducer) that transmits a rotational driving force to the counterpart device.

Conventionally, the transmission apparatus which transmits the driving force from a drive source to a counterpart apparatus is known. The counterpart device is, for example, an industrial robot or a turntable. As an example of a conventional transmission device, Patent Document 1 discloses a planetary gear reducer used for a drive mechanism for driving the wrist of an industrial robot. This planetary gear reducer decelerates the rotational driving force input from the drive motor as the driving source and transmits it to the wrist of the robot.

The planetary gear reducer includes a ring gear into which a rotational driving force from a drive motor is input, three pinion gears engaged with the ring gear, and a reduction gear that decelerates the rotation input from the pinion gear and outputs it to the wrist of the robot. This ring gear has an outer tooth and an inner tooth. The pinion provided on the output shaft of the drive motor is engaged with the outer tooth of the ring gear. The above three pinion gears mesh with the inner tooth of the ring gear. The ring gear is rotatably supported by the case via a bearing provided on the radially outer side thereof.

Japanese Patent Laid-Open No. 02-048193

In the wrist drive mechanism disclosed in Patent Document 1, the rotation shaft of the ring gear is provided in parallel with the rotation shaft of the drive source. For this reason, the drive source is arrange | positioned at the position shifted from the reducer in the direction along the rotating shaft of a ring gear. Therefore, in the conventional speed reducer, the speed reducer and the drive source cannot be arranged compactly in the direction along the rotation axis of the ring gear.

In the planetary gear reducer described above, a bearing for supporting the ring gear on the support is disposed outside the radial direction of the ring gear. For this reason, the dimension of a planetary gear reducer becomes large in the radial direction of a ring gear.

It is an object of the present invention to solve or alleviate at least part of the above problems. One of the more specific objects of the present invention is to provide a delivery device which can be made compact.

A transmission device according to one embodiment of the present invention includes a ring gear having a first gear connected to a drive source, an outer circumferential surface provided with an outer tooth engaged with the first gear, an inner circumferential surface provided with an inner tooth, and the inner tooth of the ring gear. And a second gear engaged with the gear, a reduction gear for decelerating and outputting an input from the second gear, and a bearing disposed inside the diameter square of the ring gear than the inner tooth and rotatably supporting the ring gear. Equipped.

A transmission device according to one embodiment of the present invention includes a ring gear having a first gear connected to a drive source, an outer circumferential surface provided with an outer tooth engaged with the first gear, an inner circumferential surface provided with an inner tooth, and the inner tooth of the ring gear. A reduction gear having a second gear engaged with the base, a base, a fixed portion provided so as not to rotate relative to the base, and an output portion rotating relative to the base at a speed reduced from the rotation speed of the second gear; The bearing which supports the said ring gear rotatably with respect to the said base in the radial direction inner side of the said ring gear rather than an internal tooth is provided.

A transmission device according to one embodiment of the present invention has a first gear connected to a drive source and rotating around a first rotational shaft, an outer circumferential surface provided with an outer tooth engaged with the first gear, and an inner circumferential surface provided with an inner tooth, A ring gear that rotates around a second rotation shaft extending in a direction different from the first rotation shaft, a second gear meshing with the inner tooth of the ring gear, and a deceleration section that decelerates and outputs an input from the second gear; Equipped.

In one embodiment of the present invention, the inner tooth is disposed closer to the second rotating shaft than the outer tooth in the first virtual surface that passes through the outer tooth perpendicularly to the second rotating shaft.

In one embodiment of the present invention, the deceleration portion includes a fixed portion provided so as not to rotate relative to the base portion, and a rotational portion provided inside the fixed portion and decelerated from the rotational speed of the second gear. It has an output that rotates with respect.

In one embodiment of the present invention, there is provided a main bearing disposed between the fixed part and the output part, and at least a part of the first gear is disposed between an outer circumferential surface of the main bearing and an outer circumferential surface of the fixed part. have.

In one embodiment of this invention, the said main bearing is arrange | positioned near the said 2nd rotation shaft rather than the said 1st gear in the 2nd virtual surface which passes through a said 1st gear orthogonal to the said 2nd rotation shaft.

In one embodiment of this invention, the outer peripheral surface of the said fixing part has a recessed part, and at least one part of the said 1st gear is arrange | positioned at the said recessed part.

In one embodiment of the present invention, the deceleration unit has a swinging gear that swings by the rotation of the second gear, and the swinging gear passes through the first gear perpendicular to the second rotational axis. On the surface, it is arrange | positioned near the said 2nd rotation shaft rather than the said 1st gear.

1 is a schematic view of a rotary device of one embodiment of the present invention.
2 is a schematic diagram schematically showing a part of an internal structure of a rotating device according to one embodiment of the present invention.
It is a figure explaining the detail of the rotating apparatus of one Embodiment of this invention.
It is sectional drawing which shows typically the cross section of the reducer with which the rotating apparatus of FIG. 3 is equipped.
It is an enlarged view which expands and shows a part of gear unit by other embodiment of this invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described with reference to drawings. First, with reference to FIGS. 1-4, the delivery apparatus by one Embodiment of this invention, and the rotating apparatus provided with the said delivery apparatus are demonstrated. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram schematically showing a rotating device having a delivery device according to an embodiment of the present invention, and Fig. 2 is a schematic diagram schematically showing a part of an internal structure of a rotary device according to an embodiment of the present invention. to be. 3 is a cross-sectional view schematically showing a cross section along the line A-A in FIG. 2, and FIG. 4 is a cross-sectional view schematically showing the cross section along the line B-B in FIG. 3. The illustrated rotating device is used for rotating the wrist or turntable of an industrial robot, for example.

The illustrated rotary device includes a drive source 5 and a speed reducer 10 that transmits rotation from the drive source 5 to the counterpart device. The drive source 5 is an electric motor, for example. The reducer 10 decelerates the rotation input from the drive source 5 and outputs it to the counterpart device (not shown) which becomes a drive object. The transmission device to which the present invention is applicable is not limited to the speed reducer 10.

The reducer 10 has a gear unit 100 that transmits rotation from the drive source 5, a base 15, and a speed reducer 50 supported by the base 15. The reduction gear 10 is provided with a through hole, and a normal center pipe 25 is provided in this through hole. The reduction unit 50 slows down the rotation input from the gear unit 100 and outputs the reduced rotation.

Next, the gear unit 100 will be described in more detail. The gear unit 100 includes a spur gear 1, an input gear 2, and a ring gear 3. The input gear 2 is connected to the drive shaft 111 of the drive source 5, and rotates around the first rotation shaft by a drive force input from the drive source 5.

In the illustrated embodiment, the spur gear 1 is a spur gear. The spur gear 1 applicable to this invention is not limited to a spur gear. As the spur gear 1, any gear capable of transmitting the rotation of the ring gear 3 to the reduction unit 50 (specifically, the crankshaft 80 described later) can be used. In the illustrated embodiment, the gear unit 100 has three spur gears 1, but the number of spur gears 1 provided in the gear unit 100 may be more than three or at least.

The ring gear 3 is supported on the base 15 to rotate about the rotational axis RCX. The ring gear 3 has a supporting member 7 supported on the base 15 and a ring-shaped ring member 8. The support member 7 has a disk-shaped main body 7a and a boss 7b extending in the X2 direction from the radially inner end of the main body 7a. The boss portion 7b has a substantially cylindrical shape. In the illustrated embodiment, the support member 7 and the ring member 8 are separate members, and the ring member 8 is connected to the support member 7 by bolts 14. The support member 7 and the ring member 8 may have an integral one-piece structure. The ring gear 3 has an inner tooth 4 and an outer tooth 6. More specifically, the ring member 8 of the ring gear 3 has an inner tooth 4 and an outer tooth 6. The inner tooth 4 is provided along the inner circumferential surface of the ring member 8 and meshes with the spur gear 1. The outer tooth 6 is provided along the outer circumferential surface of the ring member 8 and meshes with the input gear 2. The input gear 2 is an example of the first gear described in the claims. The spur gear 1 is an example of the second gear described in the claims.

3 shows an imaginary plane P1 passing through the outer tooth 6 orthogonal to the axis of rotation RCX. Both the inner tooth 4 and the outer tooth 6 are disposed on this virtual surface P1. In other words, the imaginary surface P1 passes through both the inner tooth 4 and the outer tooth 6. Virtual surface P1 is an example of the 1st virtual surface in a claim. In a conventional speed reducer, teeth of the gear meshing with the input gear and teeth of the gear meshing with the spur gear are disposed at positions displaced in the direction of the central axis of the speed reducer. On the other hand, in the embodiment shown in figure, since the outer tooth 6 which meshes with the input gear 2 and the inner tooth 4 which meshes with the spur gear 1 are arrange | positioned on the virtual surface P1, by this arrangement, The dimension of the center axis RCX direction of the reducer 10 can be made small. The spur gear 1 and the bolt 14 are also arranged on the said virtual surface P1. This arrangement makes it possible to further reduce the size in the direction of the center axis RCX of the reducer 10.

The ring gear 3 rotates around the rotation axis RCX (second rotation axis). The ring gear 3 is arranged so that its rotational axis RCX is not parallel to the rotational axis (first rotational axis) of the input gear 2. In the illustrated embodiment, the rotating shaft RCX of the ring gear 3 coincides with the axis passing through the center of the cylindrical through hole provided in the center of the reducer 10. Therefore, in this specification, the rotating shaft RCX may be called the center axis RCX (of the reducer 10). The second axis of rotation extends in a direction different from the first axis of rotation. Therefore, the input direction of the driving force from the drive source 5 is changed by the input gear 2 and the ring gear 3. In the illustrated embodiment, the bevel gear is configured by the input gear 2 and the ring gear 3. In addition to the bevel gear, the input gear 2 and the ring gear 3 may be screw gears, worm gears, or other gears that can change the direction of transmission of power.

The specific shape, arrangement and number of each gear that is a component of the gear unit 100 are not limited to those shown.

Next, the reduction unit 50 will be described in more detail. The reduction unit 50 includes a crankshaft 80 coupled to the spur gear 1, a crank bearing 84, a rocking gear unit 70, a case 11, a carrier 60, and a pin. Has 20.

The crankshaft 80 has a shaft main body 80a, the eccentric part 81, and the eccentric part 82. As shown in FIG. The shaft main body 80a is a cylindrical member extending in a direction parallel to the central axis RCX. The eccentric part 81 and the eccentric part 82 are cylindrical members. The eccentric part 81 and the eccentric part 82 are eccentric from the shaft main body 80a. The phase of the eccentric part 81 and the phase of the eccentric part 82 are shift | deviated 180 degree from each other. The eccentric part 82 is provided in the X2 side rather than the eccentric part 81 in the center axis | shaft RCX direction. The crankshaft 80 is fixed to the spur gear 1. In other words, the crankshaft 80 is provided so as not to rotate relative to the spur gear 1.

A plurality of crank bearings 84 are provided on the radially outer side of the eccentric portions 81 and 82. The crank bearing 84 is a needle bearing, for example.

The swing gear portion 70 includes a first swing gear 71 and a second swing gear 72 provided on the X2 side of the central swing RCX direction than the first swing gear 71. The first swing gear 71 is mounted to the eccentric portion 81 via the crank bearing 84. Similarly, the second swing gear 72 is mounted to the eccentric portion 82 via the crank bearing 84. The first swing gear 71 has a center hole 71c at its radial center, and three shaft holes 71b around the center hole 71c. The second swing gear 72 has a center hole 72c at its radial center, and three shaft holes 72b around the center hole 72c. The first swing gear 71 has an outer tooth 71a, and the second swing gear 72 has an outer tooth 72a. The number of teeth of the outer tooth 71a of the 1st rocking gear 71 and the number of teeth of the outer tooth 72a of the 2nd rocking gear 72 are the same. In the illustrated embodiment, the number of the pins 20 is one more than the number of teeth of the outer tooth 71a (outer tooth 72a).

The case 11 is provided in the radially outer side of the oscillation gear part 70. The case 11 has the case main body 11b which has a cylindrical shape, and the flange 11a provided in the radial direction outer side of the case main body 11b. The case main body 11b has the outer peripheral surface 11b1. The outer circumferential surface 11b1 of the case main body 11b is in contact with the inner circumferential surface of the flange 11a. The motor flange 112 is provided in the outer peripheral surface 11b1 of the case main body 11b. The drive source 5 is provided in the case main body 11b and the base 15 by this motor flange 112. As shown in FIG. The outer peripheral surface 11b1 of the case main body 11b is provided with the recessed part 11b2 which was concave radially inward. The recessed part 11b2 is provided in the position which opposes the drive source 5 among the outer peripheral surfaces 11b1 of the case main body 11b. As shown in FIG. 3, at least a part of the input gear 2 to which rotation is input from the drive shaft 111 of the drive source 5 is accommodated in the recess 11b2.

The inner wall of the case body 11b is formed with a plurality of grooves extending along the rotation axis RCX direction. A pin 20 is provided in each of the plurality of grooves. The pin 20 is a cylindrical member extending in the rotational axis RCX direction. As a result, the pin 20 is held by the case main body 11b.

The flange 11a is fastened to the case main body 11b and the base 15 by the bolt. The flange 11a does not rotate relative to the case body 11b and the base 15. The case 11 is an example of the fixing portion described in the claims.

The carrier 60 is provided in the radially inner side of the case 11. The carrier 60 has a first carrier body 61 and a second carrier body 62. The first swing gear 71 and the second swing gear 72 are disposed between the first carrier body 61 and the second carrier body 62. The first carrier body 61 and the second carrier body 62 have through holes extending in the center axis RCX direction at the center thereof. The first carrier body 61 has three shafts 63 protruding from the lower surface thereof in the X2 direction. The shaft 63 extends through the shaft hole 71b of the first swing gear 71 and the shaft hole 72b of the second swing gear 72 to the upper surface of the second carrier body 62. The second carrier body 62 is attached to the shaft 63 by a bolt 64. The first carrier body 61 and the second carrier body 62 do not rotate relative to each other. The first carrier body 61 and the second carrier body 62 may have an integral one-piece structure.

The first carrier body 61 is attached to the case 11 via the first main bearing 91. The second carrier body 62 is attached to the case 11 via the second main bearing 92. Part of the outer circumferential surface of the second main bearing 92 is in contact with the inner circumferential surface of the flange 11a. Thereby, the 1st carrier body 61 and the 2nd carrier body 62 are supported with respect to the case 11 so that rotation is possible.

The carrier 60 is connected to the counterpart device. This counterpart device is a turntable, the arm of an industrial robot, or a rotatable apparatus other than the above. Carrier 60 is an example of the output portion described in the claims.

The base 15 has a disk shaped bottom portion 15a and a boss portion 15b extending in the X1 direction from the radially inner end of the bottom portion 15a. The base 15 is connected to the flange 11a at the radially outer end of the bottom 15a. The boss portion 15b is substantially cylindrical in shape.

A first bearing 13a and a second bearing 13b are provided between the outer circumferential surface of the boss portion 15b of the base 15 and the inner circumferential surface of the boss portion 7b of the support member 7. The 2nd bearing 13b is arrange | positioned at the X2 side rather than the 1st bearing 13a. The 1st bearing 13a and the 2nd bearing 13b are arrange | positioned inside radial direction rather than the inner tooth 4 of the ring gear 3. That is, the 1st bearing 13a and the 2nd bearing 13b are arrange | positioned near the center axis RCX rather than the inner tooth 4 of the ring gear 3. In this way, the ring gear 3 is supported by the first bearing 13a and the second bearing 13b so as to be rotatable about the central axis RCX. In a conventional speed reducer, a bearing for supporting a ring gear is provided outside the radial direction of the ring gear. On the other hand, in the embodiment shown, since the 1st bearing 13a and the 2nd bearing 13b are arrange | positioned inside radial direction of the reducer 10 rather than the inner tooth 4, by this arrangement, It becomes possible to reduce the dimension of the radial direction (10) orthogonal to center axis RCX.

The sealing member 16 is provided between the inner peripheral surface of the boss part 15b and the outer peripheral surface of the center pipe 25. The seal member 16 is disposed in an area between the end on the X1 side of the first bearing 13a and the end on the X2 side of the second bearing 13b. In the illustrated embodiment, the first bearing 13a and the second bearing 13b supporting the ring gear 3 are not directly installed in the center pipe 25, but are radially outer side of the center pipe 25. It is provided in the boss | hub part 15b provided in this. By providing the seal member 16 between this boss | hub part 15b and the center pipe 25, the seal member 16 is at least the 1st bearing 13a and the 2nd bearing 13b in the center axis RCX direction. It can be arrange | positioned at the position which overlaps with one side. This arrangement makes it possible to reduce the size in the direction of the center axis RCX of the reducer 10.

Next, the arrangement of the input gear 2 will be described. 3 shows an imaginary surface P2 passing through the second main bearing 92 orthogonal to the axis of rotation RCX. Virtual surface P2 is an example of the 2nd virtual surface in a claim. Both the 2nd main bearing 92 and the input gear 2 are arrange | positioned on this virtual surface P2. In other words, the virtual surface P2 has passed through both the 2nd main bearing 92 and the input gear 2. The 2nd main bearing 92 is arrange | positioned near the center axis RCX rather than the input gear 2 on the virtual surface P2. This arrangement makes it possible to reduce the size in the direction of the center axis RCX of the reducer 10. In the embodiment shown, the drive shaft 111 of the drive source 5 is also arrange | positioned on the virtual surface P2. This arrangement also makes it possible to reduce the size in the direction of the center axis RCX of the reducer 10.

3 shows an imaginary surface P3 passing through a second swinging gear 72 perpendicular to the axis of rotation RCX. Virtual surface P3 is an example of the 3rd virtual surface in a claim. Both the second swing gear 72 and the input gear 2 are disposed on this imaginary surface P3. In other words, the imaginary surface P3 passes through both the second swinging gear 72 and the input gear 2. In the illustrated example, the virtual surface P3 passes near the upper end of the input gear 2. The second swing gear 72 is disposed closer to the central axis RCX than the input gear 2 on the virtual surface P3. This arrangement makes it possible to reduce the size in the direction of the center axis RCX of the reducer 10.

As shown in FIG. 3, in the direction orthogonal to the central axis RCX, at least a part of the input gear 2 is an outer circumferential surface 91a of the main bearing 91 (or an outer circumferential surface 92a of the main bearing 92). )] And the position of the outer circumferential surface 11b1 of the case main body 11b. This arrangement makes it possible to reduce the size of the reduction gear 10 in the radial direction (direction perpendicular to the central axis RCX).

Next, with reference to FIG. 5, the speed reducer by other embodiment of this invention is demonstrated. 5 is an enlarged view of a part of a cross section of a speed reducer according to another embodiment of the present invention. In the embodiment shown in FIG. 5, the configuration of the ring gear 3 is different from the embodiment shown in FIG. 3. In the embodiment shown in FIG. 5, the ring gear 3 has a supporting member 7, an outer tooth member 8a, and an inner tooth member 8b. Both the outer tooth member 8a and the inner tooth member 8b have a ring shape. The outer tooth 6 is provided in the outer peripheral surface of the outer tooth member 8a, and the inner tooth 4 is provided in the inner peripheral surface of the inner tooth member 8b. The support member 7 has a disk-shaped main body 7a and a boss 7b extending in the X2 direction from the radially inner end of the main body 7a. The outer tooth member 8a, the inner tooth member 8b, and the main body portion 7a of the support member 7 are connected by bolts 14.

Next, the operation of the speed reducer 10 will be described. When rotation is input to the input gear 2 from the drive source 5, the ring gear 3 rotates around the central axis RCX in association with the rotation of the input gear 2. The rotation of this ring gear 3 is transmitted to the spur gear 1 which is engaged with the inner tooth 4 of the ring gear. When the spur gear 1 rotates, the eccentric portion 81 and the eccentric portion 82 of the crankshaft 80 rotate eccentrically. By the eccentric rotation of this eccentric part 81 and the eccentric part 82, the 1st oscillation gear 71 and the 2nd oscillation gear 72 oscillate rotation. At this time, the center axis CX1 of the first swing gear 71 and the center axis CX2 of the second swing gear 72 are wound around the rotation center axis RCX of the carrier 60. Accordingly, the first swinging gear 71 and the second swinging gear 72 move around the inside of the case main body 11b while the outer tooth 71a and the outer tooth 72a are engaged with the pin 20. Each time the crankshaft 80 rotates once, the first swinging gear 71 rotates relative to the case 11 by only one tooth which is a difference between the number of the pins 20 and the number of teeth of the outer tooth 71a. In this way, the rotation of the crankshaft 80 is decelerated by the reduction ratio of "the number of teeth of 1 / outer tooth 71a", and is transmitted to the carrier 60. Thereby, the carrier 60 rotates with respect to the case 11 and the base 15 by the rotation speed decelerated from the rotation speed of the crankshaft 80. As described above, the rotation input from the drive source 5 to the speed reducer 10 is decelerated and output from the carrier 60 to the counterpart device.

The dimensions, materials, and arrangements of each component described herein are not limited to those explicitly described in the embodiments, and each component may have any dimensions, materials, and arrangements that may be included within the scope of the present invention. It can be modified. In addition, the component which is not explicitly demonstrated in this specification may be added to embodiment described, and some of the component demonstrated in each embodiment may be abbreviate | omitted.

Each embodiment mentioned above may be combined suitably. An embodiment realized by combining a plurality of embodiments can also be an embodiment of the present invention.

1: 2nd gear (spur gear)
2: first gear (input gear)
3: ring gear
4: internal
5: driving source
6: shouting
7: support member
8: ring member
10: reducer
11: case
13: bearing
14: Bolt
15: Donate
16: seal member
100: gear unit

Claims (12)

A first gear connected to the drive source,
A ring gear having an outer circumferential surface provided with an outer tooth engaged with the first gear and an inner circumferential surface provided with an inner tooth;
A second gear meshing with the inner tooth of the ring gear;
A reduction unit for decelerating and outputting the input from the second gear;
It is arrange | positioned inside the radial direction of the said ring gear rather than the said inner tooth, and is provided with the bearing which rotatably supports the said ring gear. A first gear connected to the drive source,
A ring gear having an outer circumferential surface provided with an outer tooth engaged with the first gear and an inner circumferential surface provided with an inner tooth;
A second gear meshing with the inner tooth of the ring gear;
Donation,
A deceleration part having a fixed part provided so as not to rotate with respect to the base, an output part rotating with respect to the base at a rotational speed reduced from the rotational speed of the second gear;
And a bearing for rotatably supporting the ring gear relative to the base in the radially inner side of the ring gear than the inner tooth. A first gear connected to the drive source and rotating around the first rotational shaft,
A ring gear having an outer circumferential surface provided with an outer tooth engaged with the first gear, an inner circumferential surface provided with an inner tooth, and rotating around a second rotating shaft extending in a direction different from the first rotating shaft;
A second gear meshing with the inner tooth of the ring gear;
And a deceleration part for decelerating and outputting the input from the second gear. The transmission device according to claim 3, wherein the internal teeth are arranged closer to the second rotary shaft than the external teeth in the first virtual surface perpendicular to the second rotary shaft and passing through the external teeth. The base according to claim 3 or 4, having a base,
And the deceleration portion has a fixed portion provided so as not to rotate with respect to the base, and an output portion provided inside the fixed portion and rotating with respect to the base at a rotational speed reduced from the rotational speed of the second gear. . 6. A main bearing according to claim 5, further comprising a main bearing disposed between the fixing part and the output part,
At least a part of said first gear is arrange | positioned between the outer peripheral surface of the said main bearing and the outer peripheral surface of the said fixed part. The said main bearing is closer to the said 2nd rotation shaft than the said 1st gear in the 2nd virtual surface which passes through a said 1st gear orthogonal to the said 2nd rotation axis, The said main bearing is in any one of Claims 3-6. And a delivery device. The outer peripheral surface of the said fixed part has a recessed part,
At least a portion of the first gear is disposed in the recess. The said deceleration part has a swing gear of Claims 3-8 which oscillates by the rotation of the said 2nd gear,
The swinging gear is disposed closer to the second rotational axis than the first gear in a third virtual surface passing through the first gear perpendicular to the second rotational axis. A first gear connected to the drive source,
A ring gear having an outer circumferential surface provided with an outer tooth engaged with the first gear and an inner circumferential surface provided with an inner tooth;
A second gear meshing with the inner tooth of the ring gear;
It is arrange | positioned inside the radial direction of the said ring gear rather than the said inner tooth, and is provided with the bearing which rotatably supports the said ring gear. A first gear connected to the drive source,
A ring gear having an outer circumferential surface provided with an outer tooth engaged with the first gear and an inner circumferential surface provided with an inner tooth;
A second gear meshing with the inner tooth of the ring gear;
Donation,
And a bearing provided between said base and said ring gear. A first gear connected to the drive source and rotating around the first rotational shaft,
A ring gear having an outer circumferential surface provided with an outer tooth engaged with the first gear, an inner circumferential surface provided with an inner tooth, and rotating around a second rotating shaft extending in a direction different from the first rotating shaft;
And a second gear meshing with the inner tooth of the ring gear.

Images