JPWO2009057526A1 - Reduction gear - Google Patents

Abstract

Provided is a speed reducer in which a support member is exposed at both end faces in the rotation axis direction. The speed reducer disclosed in this specification includes an internal gear, a carrier, a crankshaft, an external gear, and a ring gear. The carrier is arranged coaxially with the internal gear, and includes a pair of support members and carrier pins that connect the support members. The crankshaft is rotatably supported by the carrier, and the eccentric body and the crankshaft gear are fixed. The external gear rotates eccentrically while engaging with the internal gear. The ring gear is arranged coaxially with the internal gear, and includes an internal tooth that engages with the crankshaft gear and an external tooth that engages with the input gear. The outer surfaces of the pair of support members in the rotation axis direction are exposed from the case of the speed reducer.

Description

This application claims priority based on Japanese Patent Application No. 2007-284274 filed on Oct. 31, 2007. The entire contents of that application are incorporated herein by reference.
The present invention relates to a reduction gear. In particular, the present invention relates to an eccentric oscillating speed reduction device that includes an internal gear and an external gear that rotates eccentrically while engaging the internal gear inside the internal gear.

  Japanese Patent Publication No. H11-230276 (Patent Document 1) discloses an eccentric oscillating speed reduction device. The reduction gear includes an internal gear, a carrier, a crankshaft, and an external gear. The internal gear is fixed to the case. The carrier is disposed coaxially with the internal gear and is rotatably supported by the case. The carrier also includes a pair of support members and carrier pins. The pair of support members are arranged to face each other and are connected by carrier pins. The carrier pin extends along the rotation axis of the carrier. The crankshaft is disposed between the pair of support members and is rotatably supported by the pair of support members. An eccentric body and a gear are fixed to the crankshaft and extend along the rotation axis of the carrier. The gear of the crankshaft is engaged with an input gear that transmits the torque of the motor. The external gear is disposed between the pair of support members. A plurality of first through holes and a plurality of second through holes are formed along the circumferential direction of the external gear. A carrier pin is loosely fitted in the first through hole, and an eccentric body of the crankshaft is fitted in the second through hole. Since the second through hole of the external gear and the eccentric body of the crankshaft are fitted, the carrier and the external gear rotate integrally. The external gear is engaged with the internal gear. In this specification, “the carrier pin is loosely fitted in the through hole” means that the carrier pin passes through the through hole in a state where a gap is formed between the through hole and the carrier pin. Means.

In the reduction gear of Patent Document 1, the torque of the motor is transmitted to the crankshaft via the input gear. When the crankshaft rotates, the eccentric body rotates eccentrically around the axis of the crankshaft. When the eccentric body rotates eccentrically, the external gear rotates eccentrically around the axis of the internal gear while engaging with the internal gear. When the external gear rotates eccentrically around the axis of the internal gear by one turn, the external gear rotates relative to the internal gear by an angle corresponding to the difference in the number of teeth between the external gear and the internal gear. To do. That is, when the crankshaft rotates, the external gear rotates relative to the internal gear. As a result, the carrier rotates around the axis of the internal gear. In other words, the carrier rotates relative to the case. The rotation axis of the carrier becomes the output shaft of the reduction gear.
As described above, the carrier includes a pair of support members. The outer surface along the output shaft of one support member is exposed at the end of the reduction gear in the output shaft direction. A member that is rotated by the speed reducer is fixed to the exposed support member. In this specification, a member that is rotated by the speed reducer may be referred to as a “rotated member”. Further, in this specification, a member that fixes the rotated member in the reduction gear is referred to as an “output unit”. That is, one support member of the pair of support members corresponds to the output portion of the speed reducer.
The crankshaft extends from the other support member to the outside of the carrier. A gear is fixed to the shaft of the portion extending outside the carrier. In the following description, the gear fixed to the crankshaft may be referred to as a crankshaft gear. An input gear for transmitting the torque of the motor is engaged with the crankshaft gear. That is, a gear group for transmitting the torque of the motor to the crankshaft is arranged on the opposite side of the output portion of the reduction gear.

In the conventional speed reducer, a gear group is arranged on the opposite side of the output portion of the speed reducer. Therefore, the both ends of the carrier could not be used as the output part of the reduction gear. It is desired that both ends of the carrier be output parts of the speed reducer. If both ends of the carrier can be used as output portions of the speed reducer, for example, a pair of cantilevers extending from the speed reducer to both sides can be rotated.
In the present specification, the expression “the supporting member is exposed” means that the supporting member can fix the rotated member. It does not simply mean that the support member can be seen from the outside of the case when the speed reducer is observed along the rotation axis. For example, when a part of the support member is visible, but a part of the support member is hidden by the motor support for fixing the motor, it is not considered as “exposed”.
The present specification discloses a speed reducer in which carrier support members are exposed on both sides in the rotation axis direction.

  The speed reduction device disclosed in the present specification employs a ring gear in which teeth are formed on both the outer peripheral surface and the inner peripheral surface in order to transmit the torque of the motor to the crankshaft gear. In the following description, the teeth on the outer peripheral surface of the ring gear may be referred to as external teeth, and the teeth on the inner peripheral surface may be referred to as internal teeth. The ring gear is arranged coaxially with the carrier, and the inner teeth of the ring gear engage with the crankshaft gear. An input gear that engages with the external teeth of the ring gear is disposed on the outer peripheral side of the ring gear. The torque of the motor is transmitted from the input gear to the ring gear. By adopting a ring gear formed with external teeth and internal teeth, the speed reduction device disclosed in this specification has a gear group for transmitting the torque of the motor to the crankshaft on the outer side in the radial direction of the carrier. it can. It is not necessary to arrange a gear group on either side of the carrier in the rotation axis direction. Further, it is not necessary to arrange a motor or a motor support for fixing the motor on either side of the carrier in the rotation axis direction. This succeeded in exposing both sides of the carrier. That is, the speed reducer disclosed in the present specification can fix the rotated member to both ends of the carrier.

The speed reducer disclosed in this specification includes an internal gear, a carrier, a crankshaft, an external gear, and a ring gear. The internal gear is fixed to the case. The carrier is disposed coaxially with the internal gear and is rotatably supported by the case. The carrier also includes a pair of support members and carrier pins. The pair of support members are arranged to face each other and are connected by carrier pins. The carrier pin extends along the rotation axis of the carrier. The crankshaft is disposed between the pair of support members and is rotatably supported by the carrier. The crankshaft extends along the rotation axis of the carrier, and an eccentric body and a gear (crankshaft gear) are fixed. The external gear is disposed between the pair of support members. The external gear is formed with a first through hole and a second through hole penetrating in the axial direction of the reduction gear. A carrier pin is loosely fitted in the first through hole. An eccentric body of the crankshaft is fitted in the second through hole. The external gear rotates eccentrically while engaging with the internal gear as the crankshaft rotates. The number of teeth of the external gear and the number of teeth of the internal gear are different. For this reason, when the external gear rotates eccentrically around the axis of the internal gear by one turn, the external gear is relative to the internal gear by an angle corresponding to the difference in the number of teeth between the external gear and the internal gear. Rotate to. Further, as described above, the carrier pin is loosely fitted in the first through hole of the external gear. Therefore, when the external gear rotates eccentrically around the axis of the internal gear by one turn, the carrier rotates relative to the internal gear by an angle corresponding to the difference in the number of teeth between the external gear and the internal gear. To do.
The speed reducer disclosed in this specification further includes a ring gear. The ring gear is arranged coaxially with the internal gear and is rotatable relative to the internal gear. The ring gear has teeth formed on the outer peripheral surface and the inner peripheral surface. Its internal teeth are engaged with the crankshaft gear. The external teeth are engaged with an input gear that transmits the torque of the motor.
Both outer surfaces of the pair of support members in the rotation axis direction are exposed from the case. As described above, by adopting the ring gear formed with the inner teeth and the outer teeth, this reduction gear can expose both the outer surfaces of the pair of support members in the rotation axis direction from the case. is there.

  The carrier pin moves around the rotation axis of the carrier as the external gear rotates. A gear that engages with the crankshaft gear cannot be arranged in the range in which the carrier pin moves. In the speed reducer disclosed in this specification, a carrier pin and a crankshaft are disposed between a pair of support members, and they are located inside the ring gear. On the other hand, an input gear that transmits the torque of the motor to the crankshaft gear can be disposed outside the ring gear. A torque transmission path from the motor to the crankshaft gear can be secured without being obstructed by the carrier pin.

In the speed reducer disclosed in the present specification, it is preferable that the ring gear be disposed between the outer surface of the one support member in the rotation axis direction and the outer surface of the other support member in the rotation axis direction.
According to this speed reducer, the ring gear and the crankshaft gear can be meshed between the outer surfaces of the pair of support members in the rotation axis direction. In the axial direction of the reduction gear, a wide space can be secured outside the outer surfaces of the pair of support members.

  When attaching a rotated member to both of a pair of support members, it is necessary to connect a pair of support members firmly. Therefore, it is preferable to arrange the carrier pins that connect the pair of support members at positions offset as much as possible from the rotation axis of the carrier. In other words, when the speed reducer is observed along the rotation axis of the carrier, the carrier pin is located on the outer side in the radial direction of the carrier with respect to the circle that is in contact with the crankshaft gear on the center side of the carrier about the rotation axis of the carrier It is preferable to overhang. With such an arrangement of carrier pins, the pair of support members can be firmly connected to each other.

  The outer diameter of the ring gear may be smaller than the inner diameter of the internal gear. Alternatively, the outer diameter of the ring gear may be larger than the inner diameter of the internal gear. According to the former configuration, the reduction gear can be made compact. According to the latter configuration, the outer diameter of the ring gear can be freely selected, and the reduction ratio between the motor output shaft and the crankshaft can be freely set.

  The speed reducer disclosed in this specification can fix the rotated member to both ends of the carrier.

1 shows a reduction gear device with a motor according to a first embodiment; Sectional drawing along the II-II line | wire of FIG. 1 is shown. Sectional drawing along the III-III line | wire of FIG. 1 is shown. The speed reducer with a motor of 2nd Example is shown. The reduction gear with a motor of the 3rd example is shown. 4 shows a reduction gear device with a motor according to a fourth embodiment. 10 shows a reduction gear device with a motor according to a fifth embodiment. Sectional drawing along the VIII-VIII line of FIG. 7 is shown.

The features of each embodiment are described below.
(First feature) The external gear includes a first through hole and a second through hole at a position offset from the center of the external gear. A plurality of first through holes are formed at substantially equal intervals in the circumferential direction of the external gear, and carrier pins are loosely fitted in the respective first through holes. A plurality of second through holes are formed at substantially equal intervals in the circumferential direction of the external gear, and an eccentric body of the crankshaft is fitted into each second through hole.
(Second feature) The crankshaft is rotatably supported by a pair of support members by a pair of bearings.
(Third feature) In the reduction gears 9, 209, 309 and 409, gears (crankshaft gears) are fixed to the respective crankshafts, and the inner teeth of the ring gears are engaged with all of the gears. .
(Fourth feature) In the reduction gears 9, 209 and 309, a gear (crankshaft gear) is fixed to the crankshaft between a pair of bearings supporting the crankshaft.
(Fifth feature) In the reduction gears 9 and 209, two eccentric bodies are fixed to the crankshaft. A crankshaft gear is fixed to the crankshaft between the two eccentric bodies.

Embodiments will be described with reference to the drawings.
(First embodiment)
FIG. 1 shows a cross-sectional view of a reduction gear device 100 with a motor according to this embodiment. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 shows a cross-sectional view taken along line III-III in FIG. In addition, hatching of some components is abbreviate | omitted for clarification of drawing.
As shown in FIG. 1, the reduction gear device 100 with a motor includes a reduction gear device 9 and a motor unit 66. The reduction gear 9 and the motor unit 66 are integrally formed by the case 2. In the present embodiment, the reduction gear 9 will be described in detail. The reduction gear 9 includes an internal gear 32, a carrier 17, a crankshaft 28, external gears 34X and 34Y, and a ring gear 38.
As will be described later, the rotated member is fixed to the carrier 17. When the motor 60 is driven, the motor-equipped reduction gear 100 rotates the carrier 17 around the axis CL1.
The internal gear 32 is fixed to the case 2. More precisely, the internal gear 32 is formed integrally with the case 2. As shown in FIGS. 2 and 3, the internal gear 32 is formed by arranging the internal tooth pin 36 in a rotatable state in the groove 32 a formed in the case 2. In the speed reduction device 9 of the present embodiment, a portion of the case 2 where the internal tooth pin 36 is disposed is referred to as an internal gear 32. The internal gear 32 is formed in a ring shape and surrounds the external gears 34X and 34Y.

As shown in FIG. 1, the carrier 17 includes a pair of support members 18 </ b> X and 18 </ b> Y and a columnar part (carrier pin) 24. The columnar portion 24 extends from the support member 18X toward the support member 18Y along the axis CL1. Support members 18X and 18Y are fixed by bolts 54. As a result, the pair of support members 18 </ b> X and 18 </ b> Y are connected by the columnar part 24. Since the columnar portion 24 is formed integrally with the support member 18X, the number of parts constituting the reduction gear 9 is small compared to the case where the columnar portion 24 and the support members 18X and 18Y are formed separately. Reference numeral 52 denotes an alignment pin. By using the alignment pin 52, when the support members 18X and 18Y are fixed, the alignment of both can be facilitated. Further, the alignment pin 52 can prevent the positional relationship between the support members 18X and 18Y from shifting.
The bolt 54 is surrounded by a broken line 56. In FIG. 1, both the alignment pin 52 and the bolt 54 are illustrated, but actually they do not appear in the same cross section. Therefore, the periphery of the bolt 54 that does not appear in the cross section of FIG. FIG. 2 shows a cross section of the columnar portion 24. The columnar portion 24 is formed with a hole 70 for fitting the alignment pin 52 (see FIG. 1) and a screw hole 72 for the bolt 54 (see FIG. 1). The hole 70 and the screw hole 72 do not exist on the same straight line extending in the radial direction from the axis CL1. Therefore, as described with reference to FIG. 1, the alignment pin 52 and the bolt 54 do not actually appear in the same cross section.

As shown in FIG. 1, the carrier 17 is rotatably supported with respect to the case 2 by a pair of bearings 8X and 8Y. The bearing 8X is formed of a groove 14X formed in the support member 18X, a rolling element 12X, and an outer ring 10X. The bearing 8Y is formed of a groove 14Y formed in the support member 18Y, a rolling element 12Y, and an outer ring 10Y. The bearings 8X and 8Y have the same effect as the angular ball bearing. That is, the bearings 8X and 8Y prohibit the carrier 17 from moving in the thrust direction and also from moving in the radial direction. Since both the bearings 8X and 8Y use a groove formed in the support member as an inner ring, the number of parts is smaller than a bearing having an inner ring separately. The carrier 17 is arranged coaxially with the axis CL1 of the internal gear 32. Therefore, the carrier 17 rotates around the axis line CL1. The axis line CL1 can also be referred to as the axis line of the carrier 17.
The outer surfaces (outer ends) of the pair of support members 18X and 18Y in the direction of the axis CL1 are exposed from the case 2. More specifically, there are no components constituting the motored reduction gear 100 outside the outer ends of the support members 18X and 18Y. Therefore, the rotated member can be fixed to both the outer surface 16 of the support member 18X and the outer surface 58 of the support member 18Y.
As shown in FIG. 2, three columnar portions 24 are formed at equal intervals in the circumferential direction of the axis line CL1. Further, the columnar portion 24 is formed on the outer side in the radial direction of the carrier 17 from a circle in contact with the crankshaft gear 40 (details of the crankshaft gear 40 will be described later) on the center side of the carrier 17. Therefore, the columnar portion 24 can firmly connect the pair of support members 18X and 18Y shown in FIG. Even if a large force is applied to the pair of support members 18X and 18Y, the carrier 17 can be prevented from being deformed.

As shown in FIG. 1, the crankshaft 28 is disposed between the pair of support members 18X and 18Y. The crankshaft 28 is rotatably supported by a pair of support members 18X and 18Y by a pair of tapered roller bearings 26X and 26Y. The crankshaft 28 extends along the axis CL1. Two eccentric bodies 42X and 42Y and a gear 40 (crankshaft gear) are fixed to the crankshaft 28. The rotating shafts of the eccentric bodies 42X and 42Y are offset from the rotating shaft 41 of the crankshaft 28. However, the eccentric bodies 42X and 42Y have opposite offset directions. Therefore, the rotating shaft of the eccentric body 42X and the rotating shaft of the eccentric body 42Y are on opposite sides of the axis 41.
The eccentric bodies 42X and 42Y and the gear 40 are disposed between the pair of tapered roller bearings 26X and 26Y. The gear 40 is fixed to the crankshaft 28 between the eccentric body 42X and the eccentric body 42Y. That is, the gear 40 is fixed to the midpoint of the crankshaft 28 in the direction of the axis 41. Therefore, the torque applied to the gear 40 is applied to the pair of tapered roller bearings 26X and 26Y with a good balance.
As shown in FIG. 3, three crankshafts 28 are arranged at equal intervals in the circumferential direction of an external gear 34X described later. The external gear 34X can be eccentrically rotated around the axis line CL1 in a balanced manner.

As shown in FIG. 1, the external gears 34X and 34Y are disposed between the pair of support members 18X and 18Y. As shown in FIG. 3, the second through hole 29X is formed in the external gear 34X at a position offset from the center 74 of the external gear 34X. Three second through holes 29X are formed, and each second through hole 29X is formed at equal intervals in the circumferential direction. An eccentric body 42X is fitted in each of the second through holes 29X. Actually, the eccentric body 42X is fitted in the second through hole 29X via the needle roller bearing 44X. Therefore, the eccentric body 42X can rotate inside the second through hole 29X. The eccentric body 42X is circular, and the center thereof is eccentric from the axis 41 of the crankshaft 28. Therefore, when the crankshaft 28 rotates, the eccentric body 42X rotates eccentrically around the axis 41. When the eccentric body 42X rotates eccentrically, the external gear 34X rotates eccentrically around the axis CL1.
A first through hole 19X is also formed in the external gear 34X at a position offset from the center 74. Three first through holes 19X are formed, and each first through hole 19X is formed at equal intervals in the circumferential direction. The columnar portion 24 is loosely fitted in each first through hole 19X. That is, the columnar portion 24 passes through the first through hole 19X in a state where a gap is secured from the inner wall of the first through hole 19X. Since the columnar portion 24 is loosely fitted in the first through hole 19X, even if the external gear 34X rotates eccentrically, the carrier 17 (see FIG. 1) does not rotate eccentrically.

  The above description is common to the external gear 34Y (see FIG. 1). Therefore, detailed description of the external gear 34Y will be omitted by giving the same reference numerals as the reference numerals attached to the external gear 34X. However, the center of the external gear 34Y is on the opposite side of the center 74 of the external gear 34X across the axis CL1. That is, the external gear 34X and the external gear 34Y exist at positions symmetrical with respect to the axis CL1. Therefore, the rotation balance of the speed reducer 9 is kept good.

  As shown in FIG. 1, the ring gear 38 is arranged coaxially with the internal gear 32 and is rotatable with respect to the internal gear 32. The ring gear 38 is disposed between the external gear 34X and the external gear 34Y. The external gear 34X and the external gear 34Y prohibit the ring gear 38 from moving in the direction of the axis CL1. As shown in FIG. 2, the ring gear 38 has external teeth and internal teeth. The internal teeth of the ring gear 38 mesh with all three gears 40. The input gear 4 is disposed outside the ring gear 38. The input gear 4 is rotatably supported by the case 2 by a deep groove ball bearing 6 (see FIG. 1). The input gear 4 is engaged with the external teeth of the ring gear 38. The input gear 4 is engaged with a motor gear 68 fixed to the output shaft 64 of the motor 60. The input gear 4 is a gear for transmitting the torque of the motor 60 to the ring gear 38.

  Here, the effect of engaging the motor gear 68 with the input gear 4 that engages with the ring gear 38 will be described. As described above, the ring gear 38 is disposed inside the internal gear 32. The ring gear 38 is disposed between the external gears 34X and 34Y. Therefore, the input gear 4 and the internal gear 32 overlap each other at the portion where the torque of the motor 60 is transmitted to the ring gear 38. In order for the input gear 4 and the ring gear 38 to mesh with each other, it is necessary to divide the internal gear 32 in the direction of the axis CL1 (see reference numerals 32X and 32Y in FIG. 1). An internal tooth pin 36X is fitted in the internal gear 32X. An internal tooth pin 36Y is fitted in the internal gear 32Y. That is, the internal tooth pin 36X and the internal tooth pin 36Y are prepared separately. If the range in which the internal gear 32 is divided into the internal gear 32X and the internal gear 32Y is wide, the number of parts constituting the reduction gear 9 increases.

  When the ring gear 38 and the motor gear 68 are directly meshed (also referred to as fixing the input gear 4 to the motor output shaft 64), the diameter of the motor gear 68 must be increased. Alternatively, the distance between the ring gear 38 and the output shaft 64 of the motor 60 must be shortened. However, when the diameter of the motor gear 68 is increased, the curvature of the outer periphery of the motor gear 68 is decreased. Therefore, the range in which the internal gear 32 is divided into the internal gear 32X and the internal gear 32Y becomes wide. As a result, the number of parts constituting the reduction gear 9 increases. By interposing the input gear 4 between the ring gear 38 and the motor gear 68, the range divided into the internal gear 32X and the internal gear 32Y can be narrowed. By using the motor gear 68 without directly fixing the input gear 4 to the output shaft 64 of the motor 60, the number of parts of the entire reduction gear 9 can be reduced as a result. If the range divided into the internal gear 32X and the internal gear 32Y is narrow, the internal pin 36X and the internal pin 36Y can be omitted. More specifically, in a range where the input gear 4 and the internal gear 32 overlap, a structure in which the external gears 34X and 34Y are not meshed with the internal gear 32 can be employed. When the range divided into the internal gear 32X and the internal gear 32Y is narrow and the rotational torque applied to the internal gear 32 is relatively small, the range where the input gear 4 and the internal gear 32 overlap. Rotational torque can be transmitted only by the internal gear 32 other than. Also in this case, an increase in the number of parts can be prevented. If the distance between the ring gear 38 and the output shaft 64 of the motor 60 is shortened, the motor 60 covers the outer surface 58 of the support member 18Y. The rotated member cannot be fixed to the outer side surface 58. That is, the rotated member cannot be fixed to both ends of the carrier 17.

Another effect obtained by engaging the motor gear 68 with the input gear 4 will be described.
As described above, when the input gear 4 engaged with the ring gear 38 is directly fixed to the output shaft 64 of the motor 60, the diameter of the input gear 68 may be increased. In the speed reducer with motor 100, the speed reducer 9 and the motor unit 66 are integrally formed by the case 2. That is, the motor gear 68 is accommodated in the case 2. Therefore, when the diameter of the motor gear 68 is increased, the size of the reduction device 100 with the motor is increased. By using the motor gear 68 in addition to the input gear 4, the diameter of the gear (motor gear 68) fixed to the output shaft 64 of the motor 60 can be reduced. Thereby, the size of the reduction device 100 with a motor can be reduced.
In addition, the reduction ratio between the output shaft 64 of the motor and the crankshaft 28 can be adjusted more easily than when the input gear 4 is fixed to the output shaft 64 of the motor.

Next, the operation mechanism of the reduction gear device with motor 100 will be described. In the following description, alphabetical subscripts may be omitted when describing an event common to substantially the same parts having a plurality of parts.
When the output shaft 64 of the motor 60 rotates, the crankshaft 28 rotates via the motor gear 68, the input gear 4, the ring gear 38, and the crankshaft gear 40. The rotation of the output shaft 64 of the motor 60 can be decelerated and transmitted to the crankshaft 28. When the crankshaft 28 rotates, the eccentric body 42 rotates eccentrically. In other words, the rotation shaft of the eccentric body 42 moves around the axis 41 of the crankshaft 28. When the eccentric body 42 rotates eccentrically, the external gear 34 rotates eccentrically around the axis CL <b> 1 of the internal gear 32. The external gear 34 rotates eccentrically around the axis CL <b> 1 while meshing with the internal gear 32. Therefore, the external gear 34 rotates with respect to the internal gear 32 by a difference in the number of teeth from the internal gear 32. As a specific example, in the case of the speed reducer 9, the number of teeth of the external gear 34 is 39, and the number of teeth of the internal gear 32 (number of internal teeth pins) is 40. When the external gear 34 rotates eccentrically about the axis line CL1 (ie, the crankshaft 28 rotates 40 times), the external gear 34 rotates about the axis line CL1 once. That is, when the crankshaft rotates 40 times, the external gear 34 rotates once with respect to the internal gear 32. As the external gear 34 rotates, the crankshaft 28 moves once around the axis CL1.
As described above, the columnar portion 24 of the carrier 17 is loosely fitted in the first through hole 19 of the external gear 34. Therefore, when the crankshaft 28 rotates 40 times, the support member 18 rotates once around the axis CL1. In other words, the carrier 17 rotates once with respect to the case 2. A rotated member (not shown) fixed to both end surfaces (the outer surface 16 and the outer surface 58) of the carrier 17 can be rotated.

  As described above, when the external gear 34 rotates around the axis CL1, the crankshaft 28 moves around the axis CL1. Therefore, the gear 40 fixed to the crankshaft 28 also moves around the axis line CL1 (see FIG. 2). That is, while the speed reducer 9 operates, the positional relationship between the input gear 4 and the gear 40 always changes. In the reduction gear 9 of the present embodiment, the input gear 4 and the gear 40 can always be engaged by adopting the ring gear 38 in which inner teeth and outer teeth are formed.

The characteristics of the reduction gear 9 will be described.
By adopting the ring gear 38 formed with external teeth and internal teeth, the torque of the motor 60 can be transmitted from the outside of the ring gear 38 to the crankshaft 28. In other words, the input gear 4 for transmitting the torque of the motor 60 to the gear 40 can be arranged on the outer side in the radial direction of the axis CL <b> 1 than the crankshaft 28. There is no need to arrange the input gear 4 outside the carrier 17 in the direction of the axis CL1. The outer surface of the carrier 17 in the direction of the axis CL1 can be exposed from the case 2. That is, both the outer surface 16 of the support member 18X and the outer surface 58 of the support member 18Y can be exposed. Thereby, the speed reducer 9 has an output part which fixes a to-be-rotated member on the both sides of an axis line CL1 direction.

As shown in FIG. 2, the columnar portion 24 that connects the pair of support members 18X and 18Y is arranged at a position that is largely offset from the axis CL1. In other words, the columnar portion 24 is located outside the circle that is in contact with the gear 40 on the center side of the carrier 17 (see FIG. 1) with the axis CL1 as the center. Although the columnar portion 24 and the crankshaft 28 both move around the axis CL1, the ring gear 38 has external teeth, and the column gear portion 24 can be largely offset from the axis CL1. This is because the input gear 4 is engaged. The pair of support members 18X and 18Y that fix the member to be rotated can be firmly connected by the plurality of columnar portions 28 that are largely offset from the axis CL1.
As will be described later, the speed reducer 9 has a through hole formed in the center of the carrier 17. It is geometrically possible to fix the rotated members on both sides of the reduction gear 9 in the direction of the axis CL1 through the through hole. However, such a through hole is smaller than a circle that contacts the gear 40 of the crankshaft 28 on the center side of the carrier 17. Therefore, a member having a large diameter (a member for fixing the members to be rotated) cannot be passed through the through hole formed in the center of the carrier 17. With such a through hole, the rotated members disposed on both sides of the speed reduction device 9 cannot be firmly connected. In the speed reduction device 9 of the present embodiment, a pair of support members 18X and 18Y exposed on both sides of the speed reduction device 9 are firmly connected by a columnar portion 24. Therefore, the rotated member can be firmly fixed to both sides of the reduction gear 9 in the direction of the axis CL1.

Other features of the reduction gear 9 will be described.
As shown in FIG. 1, an oil seal 30 </ b> X is disposed between the support member 18 </ b> X and the case 2. An oil seal 30Y is disposed between the support member 18Y and the case 2. The oil seals 30 </ b> X and 30 </ b> Y can prevent oil in the speed reduction device 9 from leaking outside the speed reduction device 9.
A through hole 20 is formed at the center of the support member 18X, and a through hole 48 is formed at the center of the support member 18Y. A through hole 46X is formed at the center of the external gear 34X, and a through hole 46Y is formed at the center of the external gear 34Y. Since the through holes 20, 48, 46X, and 46Y communicate with each other, wiring, piping, and the like can be passed between the outer surface 16 and the outer surface 58.

(Second embodiment)
With reference to FIG. 4, the motor-equipped reduction device 200 will be described. The reduction gear device with motor 200 is a modification of the reduction gear device with motor 100. Therefore, description may be abbreviate | omitted by attaching | subjecting the same code | symbol or the same code | symbol to the last 2 digits to the components substantially the same as the reduction gear apparatus 100 with a motor.
In the reduction gear 209, the outer diameter of the ring gear 238 is larger than the inner diameter of the internal gears 232X and 232Y. Therefore, the ring gear 238 is arranged so as to overlap the internal gears 232X and 232Y over the entire circumference of the internal gears 232X and 232Y. The ring gear 238 is disposed between the external gear 34X and the external gear 34Y. As a result, the internal gear 232X that meshes with the external gear 34X and the internal gear 232Y that meshes with the external gear 34Y are formed separately. The ring gear 238 is rotatably supported by the case 202 by a pair of deep groove ball bearings 206X and 206Y. In the motorized reduction gear 200, an input gear 268 that engages with the ring gear 238 is fixed to the output shaft 64 of the motor.

  The characteristics of the reduction gear 209 will be described. In the reduction gear 209, the internal gears 232X and 232Y are divided in the direction of the axis CL1. Therefore, a gap is formed between the internal gear 232X and the internal gear 232Y. A ring gear 238 is disposed in the gap. The outer diameter of the ring gear 238 is not limited by the inner diameter of the internal gears 232X and 232Y. The ring gear 238 and the input gear 268 can be directly meshed without extremely increasing the diameter of the input gear 268, that is, without increasing the size of the case 202. As in the reduction gear 9 of the first embodiment, it is possible to omit the engagement of the motor gear 68 (see FIG. 1) with the input gear 4. In other words, the torque of the motor 60 can be transmitted to the crankshaft gear 40 with only one input gear 268. Further, since the ring gear 238 is supported by the case 202 by the pair of deep groove ball bearings 206X and 206Y, the ring gear 238 is less likely to be displaced.

(Third embodiment)
With reference to FIG. 5, the motor-equipped reduction device 300 will be described. The reduction gear device with motor 300 is a modification of the reduction gear device with motor 200. Therefore, description may be abbreviate | omitted by attaching | subjecting the same code | symbol to the component substantially the same as the deceleration apparatus 200 with a motor, or the same code | symbol in the last two digits.
An eccentric body 42X, an eccentric body 42Y, and a gear 40 are fixed to the crankshaft 28. The parts fixed to the crankshaft 28 are the same as those of the reduction gear 209. However, the fixed position is different. In the reduction gear 309, the gear 40 is not fixed between the eccentric body 42X and the eccentric body 42Y. The gear 40 is fixed to the crankshaft 28 outside the range where the eccentric body 42X and the eccentric body 42Y are fixed. Therefore, the ring gear 338 that meshes with the gear 40 is not disposed between the external gear 34X and the external gear 34Y. The outer diameter of the ring gear 338 is larger than the inner diameter of the internal gear 332. That is, the ring gear 338 and the internal gear 332 are overlapped over the entire circumference.
When the ring gear is arranged between the two external gears, and the ring gear and the internal gear are overlapped over the entire circumference, the two internal teeth that are engaged with the respective external gears It is necessary to prepare gears. On the other hand, in the reduction gear 309 of the present embodiment, the ring gear 338 is not disposed between the external gear 34X and the external gear 34Y. Therefore, even if the ring gear 338 and the internal gear 332 overlap over the entire circumference, it is not necessary to prepare two internal gears. Alternatively, the internal gear 332 may not be divided in the direction of the axis CL1. That is, the internal gear that meshes with the external gear 34X and the internal gear that meshes with the external gear 34Y can be integrally formed. The number of parts constituting the speed reducer 309 can be reduced.

(Fourth embodiment)
With reference to FIG. 6, the motor-equipped reduction device 400 will be described. A reduction gear device with motor 400 is a modification of the reduction gear units 200 and 300 with motor. Therefore, description may be abbreviate | omitted by attaching | subjecting the same code | symbol or the same code | symbol to the last 2 digits to the components substantially the same as the speed reducer 200,300.
In the reduction gear 409, the eccentric body 42 </ b> X, the eccentric body 42 </ b> Y, and the gear 440 are fixed to the crankshaft 28. The eccentric body 42X and the eccentric body 42Y are disposed between the pair of tapered roller bearings 26X and 26Y. The gear 440 is fixed to the crankshaft 28 outside the pair of tapered roller bearings 26X and 26Y. Further, a columnar portion 424 extends from the support member 418Y toward the support member 418X, and the support member 418X and the columnar portion 424 are fixed by a bolt 54. An additional support member 480 is fixed to the support member 418Y by bolts 482 and 484. In the reduction gear 409, a carrier 417 is formed by the support members 418X and 418Y and the additional support member 480. The rotated member can be fixed to the outer surface 16 of the support member 418X and the outer surface 458 of the additional support member 480.
In the reduction gear 409 of the present embodiment, the gear 440 can be fixed to the crankshaft 28 after the crankshaft 28 is supported by the support members 418X and 418Y. Since the gear 440 is fixed in a state where the crankshaft 28 is supported, the assembling work is easy to perform. Further, the meshing state of the gear 440 and the ring gear 438 can be easily adjusted.
A through hole 20 is formed at the center of the support member 418X, and a through hole 448 is formed at the center of the support member 418Y. A through hole 46X is formed at the center of the external gear 34X, and a through hole 46Y is formed at the center of the external gear 34Y. By forming the through holes 20, 448, 46X, and 46Y, the speed reduction device 409 is reduced in weight. Note that the through holes 20, 448, 46X, and 46Y may not be formed. For example, if the through holes 20 and 448 are not formed, the strength of the carrier 417 can be increased. Further, the support member 418Y and the additional support member 480 may be integrally formed.

(5th Example)
The motored speed reducer 500 will be described with reference to FIGS. FIG. 8 shows a cross-sectional view taken along line VIII-VIII in FIG. The reduction gear unit with motor 500 is a modification of the reduction gear unit with motor 400. Therefore, components that are substantially the same as the reduction gear unit with motor 400 may be denoted by the same reference numerals and description thereof may be omitted.
The speed reducer 509 of this embodiment also has three second through holes 29 formed at equal intervals in the circumferential direction of the external gear 34, and the eccentric body 42 is fitted in each second through hole 29. (See FIG. 3). That is, three crankshafts 28 are provided. However, the gear 540 is fixed to only one of the three crankshafts 28. As shown in FIG. 8, one gear 540 (crankshaft gear) and the internal teeth of the ring gear 538 are engaged with each other. The crankshaft 28 (not shown) to which the gear 540 is not fixed is arranged to maintain the rotational balance of the external gear 34.
Since the speed reduction device 509 of the present embodiment needs only one gear 540 to be fixed to the crankshaft 28, the number of parts constituting the speed reduction device 509 can be reduced. Further, the support member 518Y can be made larger than the support member 418Y (see FIG. 6) of the reduction gear 409. That is, the contact area between the support member 518Y and the additional support member 580 can be increased. Even if a large force is applied to the carrier 517, the carrier 517 can be prevented from being deformed.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

In the first embodiment, the crankshaft 28 is rotatably supported by the pair of support members 18X and 18Y by the pair of tapered roller bearings 26X and 26Y. However, the crankshaft is not necessarily supported by the pair of support members 18X and 18Y. For example, a crankshaft having a through hole in the axial direction of the speed reducer is prepared, a pair of support members are connected by a columnar columnar part, and the columnar part is fitted into the throughhole of the crankshaft through a bearing. May be. Even in that case, the crankshaft can be made rotatable with respect to the pair of support members. In other words, the crankshaft only needs to be supported so as to be rotatable with respect to the carrier. Similarly, in the second to fifth embodiments, the crankshaft may be supported so as to be rotatable with respect to the carrier.
According to said structure, a cylindrical columnar part can be substituted for the columnar part (carrier pin) of a carrier. The first through hole into which the carrier columnar part is loosely fitted and the second through hole into which the eccentric body of the crankshaft is fitted can be used as the same hole.

The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

Claims (5)

An internal gear fixed to the case;
A carrier that is arranged coaxially with the internal gear and is rotatably supported by the case, and a pair of opposing support members connected by carrier pins extending along the rotation axis;
A crankshaft rotatably supported between the pair of support members, extending along the rotation axis, and having the eccentric body and the crankshaft gear fixed thereto;
It is arranged between a pair of support members, a carrier pin is loosely fitted in the first through hole, and the eccentric body is fitted in the second through hole. An external gear that rotates eccentrically while engaging;
It is arranged coaxially with the internal gear and is rotatable with respect to the internal gear, teeth are formed on the outer peripheral surface and the inner peripheral surface, and the internal teeth are engaged with the crankshaft gear. A ring gear whose outer teeth are engaged with an input gear that transmits the torque of the motor,
A speed reducing device, wherein an outer side surface of each support member in a rotation axis direction is exposed from the case.   The speed reducer according to claim 1, wherein the ring gear is disposed between an outer surface of one support member and an outer surface of the other support member.   When observed along the rotation axis of the carrier, the carrier pin projects outwardly in the radial direction of the carrier from the circle that contacts the crankshaft gear on the center side of the carrier with the rotation axis of the carrier as the center. The speed reducer according to claim 1 or 2.   The reduction gear according to any one of claims 1 to 3, wherein an outer diameter of the ring gear is smaller than an inner diameter of the internal gear. The reduction gear according to any one of claims 1 to 3, wherein an outer diameter of the ring gear is larger than an inner diameter of the internal gear.

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