JP2018009699A - Reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reduction gear capable of acquiring a large reduction ratio with a simple configuration.SOLUTION: An external gear 16 on an input shaft 2 side and an external gear 26 on an output shaft 3 side are integrally provided and rotate around an eccentric wheel 30 fixed to the input shaft 2. An internal gear 11 meshing with the external gear 16 on the input shaft 2 side is fixed to a housing 5. An internal gear 21 meshing with the external gear 26 on the output shaft 3 side is coaxial with a shaft center AX of the input shaft 2. When the input shaft 2 rotates by the drive of a motor 6, the external gear 16 revolves around the circumference of the shaft center AX of the input shaft 2. The external gear 16 on the input shaft 2 side performs driven-rotation around an axial center of the eccentric wheel 30 by the internal gear 11. The external gear 26 on the output shaft 3 side rotates around the axial center of the eccentric wheel 30 integrally with the external gear 16 on the input shaft 2 side. The internal gear 21 on the output shaft 3 side performs driven-rotation to the external gear 26 on the output shaft 3 side. The output shaft 3 reduces the rotation speed of the input shaft 2, and rotates.SELECTED DRAWING: Figure 1

Description

本発明は減速機に関する。   The present invention relates to a reduction gear.

減速機は入力軸、回転子、出力軸を備える。入力軸は外力で回転し、回転子は入力軸の回転速度を減速し、出力軸は回転子が減速した回転速度で回転する。一般に入力軸の軸心と出力軸の軸心を同心とする減速機は、波動歯車、遊星歯車等の高精度で複雑な機構を用いる。   The speed reducer includes an input shaft, a rotor, and an output shaft. The input shaft rotates with external force, the rotor reduces the rotational speed of the input shaft, and the output shaft rotates at the rotational speed reduced by the rotor. In general, a speed reducer in which the axis of an input shaft and the axis of an output shaft are concentric uses a highly accurate and complicated mechanism such as a wave gear or a planetary gear.

特許文献１に記載の増速機はロータを備える。ロータはオルダム継手を介し入力軸と連結する。ロータは内部に偏心輪を摺動回転自在に支持する。偏心輪は出力軸に結合する。出力軸は固定外歯車の貫通孔を貫通する。固定外歯車は筐体に固定し、ロータ内部の内歯車に噛合する。ロータは入力軸の回転に伴い回転し、固定外歯車の周囲を自転しつつ公転する。ロータの公転によって、偏心輪は出力軸の周囲を自転しつつ公転し、出力軸を回転する。   The speed increaser described in Patent Document 1 includes a rotor. The rotor is connected to the input shaft through an Oldham coupling. The rotor supports the eccentric ring so that it can slide and rotate. The eccentric ring is coupled to the output shaft. The output shaft passes through the through hole of the fixed external gear. The fixed external gear is fixed to the housing and meshed with the internal gear inside the rotor. The rotor rotates as the input shaft rotates, and revolves while rotating around the fixed external gear. Due to the revolution of the rotor, the eccentric wheel revolves while rotating around the output shaft to rotate the output shaft.

特開２０１２−１４７６６５号公報JP2012-147665A

特許文献１の増速機で入力軸一回転あたりの出力軸の回転数を表す減速比（変速比とも言う）は、内歯車と固定外歯車の歯車比に応じた比率になる。より大きな減速比を得るには、増速機はロータを大型化し、固定外歯車に対する内歯車の歯車比を大きくする必要がある。   A reduction gear ratio (also referred to as a gear ratio) representing the rotation speed of the output shaft per one rotation of the input shaft in the speed increaser of Patent Document 1 is a ratio corresponding to the gear ratio between the internal gear and the fixed external gear. In order to obtain a larger reduction gear ratio, the speed increaser needs to enlarge the rotor and increase the gear ratio of the internal gear to the fixed external gear.

本発明の目的は簡易な構成で大きな減速比を得られる減速機を提供することである。   An object of the present invention is to provide a reduction gear capable of obtaining a large reduction ratio with a simple configuration.

本発明の一態様によれば、所定の軸方向の一方側に設け、前記軸方向に延びる軸心を中心に外力によって回転する入力軸と、前記軸方向の他方側に前記軸心と同心に設け、且つ前記入力軸とは独立に回転する出力軸と、前記入力軸と前記出力軸に連結し、前記入力軸の回転速度を減速して前記出力軸を回転する回転子とを備えた減速機において、前記回転子は、前記入力軸に接続し、且つ前記入力軸の軸心に対し所定の偏心量で偏心する偏心輪と、外歯車と、前記外歯車の径方向外側で前記外歯車に噛合し、前記外歯車より歯数が多い内歯車とを組とする少なくとも二組の歯車組とを備え、前記歯車組は、前記外歯車が前記偏心輪の外周に設けて前記偏心輪の回転軸を中心に回転可能で、且つ前記内歯車の軸心が前記入力軸の軸心と同心であり、前記二組の歯車組は前記軸方向に隣接し、且つ隣り合う前記歯車組の前記外歯車同士が接合し、接合する前記外歯車同士の外径は互いに異なり、前記出力軸は前記軸方向の他方側に位置する前記歯車組の前記内歯車に接続することを特徴とする減速機が提供される。   According to one aspect of the present invention, an input shaft is provided on one side in a predetermined axial direction and is rotated by an external force around an axial center extending in the axial direction, and concentric with the axial center on the other side in the axial direction. A reduction gear provided with an output shaft that rotates independently of the input shaft, and a rotor that is connected to the input shaft and the output shaft and that rotates the output shaft by reducing the rotational speed of the input shaft. In the machine, the rotor is connected to the input shaft and is eccentric with a predetermined eccentricity with respect to the axis of the input shaft, an external gear, and the external gear on the radially outer side of the external gear. And at least two sets of gear sets each having an internal gear with more teeth than the external gear, and the gear set is provided on the outer periphery of the eccentric ring. It can rotate around a rotation axis, and the axis of the internal gear is concentric with the axis of the input shaft. The two gear sets are adjacent to each other in the axial direction, and the outer gears of the adjacent gear sets are joined to each other, the outer diameters of the joined outer gears are different from each other, and the output shaft is the axial direction. A reduction gear is provided which is connected to the internal gear of the gear set located on the other side of the gear.

減速機は内歯車に対する外歯車の偏心量と、外歯車の外径とに応じた減速比を得る。減速機は歯車組が二組である。外歯車同士は接合し偏心輪の回転中心を中心に回転可能である。内歯車は軸心を中心に出力軸と一体に回転する。入力軸が一回転した時、外歯車は内歯車との歯数差の分だけ偏心輪の回転中心を中心に回転する。減速機は、二組の歯車組で十分な減速比を得ることができる。故に減速機は、回転子に波動歯車、遊星歯車等の高精度で複雑な機構を用いず、簡易な構成で、より大きな減速比を得ることができる。   The reduction gear obtains a reduction ratio according to the amount of eccentricity of the external gear with respect to the internal gear and the outer diameter of the external gear. The speed reducer has two sets of gears. The external gears are joined to each other and can rotate around the center of rotation of the eccentric ring. The internal gear rotates integrally with the output shaft about the shaft center. When the input shaft makes one revolution, the external gear rotates around the center of rotation of the eccentric wheel by the difference in the number of teeth from the internal gear. The reduction gear can obtain a sufficient reduction ratio with two gear sets. Therefore, the speed reducer can obtain a larger reduction ratio with a simple configuration without using a highly accurate and complicated mechanism such as a wave gear or a planetary gear for the rotor.

本態様において、前記入力軸は、前記軸方向の他方側に位置する前記歯車組の前記外歯車よりも前記軸方向の他方側に延びる先端部を有し、前記回転子は、前記先端部に接続して前記入力軸と共に回転する錘を備え、前記錘は、前記軸方向から見て前記入力軸の軸心に対し前記偏心輪の回転中心と反対側に重心位置を有してもよい。減速機は入力軸の先端部に錘を接続する。錘の重心位置は軸心に対し、軸方向視で偏心輪、軸受及び外歯車の重心位置と反対側に位置する。錘は、偏心輪の回転に伴い入力軸に作用する遠心力の不釣り合いを抑制する。故に減速機は入力軸の振動を低減できる。   In this aspect, the input shaft has a distal end portion that extends to the other side in the axial direction than the external gear of the gear set located on the other side in the axial direction, and the rotor is disposed on the distal end portion. A weight that is connected and rotates together with the input shaft may be provided, and the weight may have a center of gravity on the opposite side of the center of rotation of the eccentric wheel with respect to the axis of the input shaft when viewed from the axial direction. The reducer connects a weight to the tip of the input shaft. The center of gravity of the weight is located on the opposite side of the center of gravity of the eccentric wheel, the bearing, and the external gear as viewed in the axial direction with respect to the axis. The weight suppresses unbalance of centrifugal force acting on the input shaft as the eccentric wheel rotates. Therefore, the reduction gear can reduce the vibration of the input shaft.

本態様において、前記回転子は、前記歯車組を収容する筐体と、前記筐体に設け、前記錘が回転可能な状態で前記先端部を支持する支持体とを備えてもよい。減速機は偏心輪の回転に伴う入力軸の振動をより確実に低減できる。   In this aspect, the rotor may include a housing that houses the gear set, and a support that is provided in the housing and supports the tip portion in a state where the weight is rotatable. The reduction gear can more reliably reduce the vibration of the input shaft accompanying the rotation of the eccentric wheel.

本態様において、前記入力軸は、前記軸方向の他方側に位置する前記歯車組の前記外歯車よりも前記軸方向の他方側に延びる先端部を有し、前記回転子は、前記歯車組を収容する筐体と、前記筐体に設け、前記入力軸が回転可能な状態で前記先端部を支持する支持体とを備えてもよい。減速機は支持体で入力軸を補強し入力軸を細くできる。故に減速機は偏心輪の径方向の大きさをなるべく小さくし且つ偏心量を大きくできる。   In this aspect, the input shaft has a tip portion that extends to the other side in the axial direction than the external gear of the gear set located on the other side in the axial direction, and the rotor includes the gear set. You may provide the housing | casing to accommodate and the support body which is provided in the said housing | casing and supports the said front-end | tip part in the state which the said input shaft can rotate. The speed reducer can reinforce the input shaft with a support and make the input shaft thinner. Therefore, the reduction gear can reduce the size of the eccentric wheel in the radial direction as much as possible and increase the amount of eccentricity.

本態様において、前記偏心輪は、前記入力軸に固定し、且つ前記入力軸の軸心に対し偏心する内側偏心輪と、前記内側偏心輪の外周側に設けて前記内側偏心輪に固定し、且つ前記内側偏心輪の軸心に対し偏心する外側偏心輪とを備え、前記外側偏心輪は、前記内側偏心輪に対する回転位置を変更可能であってもよい。偏心輪は、内側偏心輪に外側偏心輪を固定する位置を変更し、入力軸に対する外側偏心輪の偏心量を変更できる。故に偏心輪は偏心量を調整し、内歯車に対し外歯車が深く噛み合った状態にできる。減速機は歯車組の隙間を減らし、回転力の伝達における損失を低減できる。   In this aspect, the eccentric wheel is fixed to the input shaft and is eccentric to the axis of the input shaft, and is provided on the outer peripheral side of the inner eccentric wheel to be fixed to the inner eccentric wheel. And an outer eccentric ring that is eccentric with respect to the axis of the inner eccentric ring, and the outer eccentric ring may be capable of changing a rotational position with respect to the inner eccentric ring. The eccentric ring can change the eccentric amount of the outer eccentric ring with respect to the input shaft by changing the position where the outer eccentric ring is fixed to the inner eccentric ring. Therefore, the eccentric wheel can adjust the amount of eccentricity so that the outer gear is deeply engaged with the inner gear. The speed reducer can reduce the gap in the gear set and reduce the loss in transmission of rotational force.

本態様において、前記偏心輪と前記外歯車の間に軸受を備えてもよい。減速機は偏心輪に対する外歯車の回転を円滑に行い、回転力の伝達における損失を低減できる。   In this aspect, a bearing may be provided between the eccentric wheel and the external gear. The speed reducer can smoothly rotate the external gear with respect to the eccentric ring, and can reduce loss in transmission of rotational force.

本態様において、前記歯車組は、前記軸方向の一方側から他方側に向けて、第一歯車組、第二歯車組、第三歯車組を有し、前記第二歯車組の外歯車は、前記第一歯車組の外歯車と一体に固定し、前記軸方向の長さが前記第一歯車組の外歯車よりも長く且つ前記軸方向の他方側が径方向外側に突出し、前記第二歯車組の外歯車の外径は、前記第一歯車組の外歯車の外径と異なり、前記第三歯車組の外歯車は、前記第二歯車組の外歯車と一体に形成し且つ前記第一歯車組の外歯車、前記第二歯車組の外歯車と異なる外径であり、前記第三歯車組の内歯車は、前記出力軸に固定し、前記第二歯車組の内歯車は、前記第三歯車組の内歯車と一体に形成し且つ前記出力軸及び前記第三歯車組の内歯車と前記軸方向に移動可能であり、前記出力軸が前記軸方向の他方側に移動した時、前記第二歯車組の内歯車と前記第二歯車組の外歯車は噛合し、前記第三歯車組の内歯車と前記第三歯車組の外歯車は噛合状態を解除し、前記出力軸が前記軸方向の一方側に移動した時、前記第二歯車組の内歯車と前記第二歯車組の外歯車は噛合状態を解除し、前記第三歯車組の内歯車と前記第三歯車組の外歯車は噛合してもよい。出力軸が軸方向に移動することで、減速機は、第二歯車組と第三歯車組を択一的に第一歯車組と接続する。第二歯車組の外歯車と第三歯車組の外歯車は外径が異なる。故に減速機は減速比を変更できる。   In this aspect, the gear set has a first gear set, a second gear set, and a third gear set from one side to the other side in the axial direction, and the external gear of the second gear set is: Fixed integrally with the external gear of the first gear set, the axial length is longer than the external gear of the first gear set, and the other side of the axial direction protrudes radially outward, the second gear set The external gear of the third gear set is different from the external diameter of the external gear of the first gear set, and the external gear of the third gear set is formed integrally with the external gear of the second gear set and the first gear The external gear of the set is different from the external gear of the second gear set, the internal gear of the third gear set is fixed to the output shaft, and the internal gear of the second gear set is the third gear It is formed integrally with the internal gear of the gear set and is movable in the axial direction with respect to the output shaft and the internal gear of the third gear set, and the output shaft is the shaft The internal gear of the second gear set meshes with the external gear of the second gear set, and the internal gear of the third gear set and the external gear of the third gear set mesh. When the output shaft moves to one side in the axial direction, the internal gear of the second gear set and the external gear of the second gear set are released from meshing, and the inner gear of the third gear set is released. The gear and the external gear of the third gear set may mesh with each other. As the output shaft moves in the axial direction, the speed reducer alternatively connects the second gear set and the third gear set to the first gear set. The outer gears of the second gear set and the third gear set have different outer diameters. Therefore, the reduction gear can change the reduction ratio.

減速機１の縦断面斜視図。FIG. 3 is a perspective view of a longitudinal section of the speed reducer 1. 減速機１の分解斜視図。FIG. 2 is an exploded perspective view of the speed reducer 1. 偏心輪３０の分解斜視図。2 is an exploded perspective view of the eccentric ring 30. FIG. 偏心輪３０の動作説明図。The operation explanatory view of eccentric wheel 30. 歯車組１０の動作説明図。FIG. 6 is an operation explanatory diagram of the gear set 10. 歯車組２０の動作説明図。FIG. 6 is an operation explanatory diagram of the gear set 20. 減速機１０１の縦断面図。The longitudinal cross-sectional view of the reduction gear 101. FIG.

本発明の一実施形態である減速機１の構造を説明する。減速機１は入力軸２の回転速度を減速して出力軸３を回転する機構である。   The structure of the reduction gear 1 which is one Embodiment of this invention is demonstrated. The speed reducer 1 is a mechanism that reduces the rotational speed of the input shaft 2 and rotates the output shaft 3.

図１、図２に示す如く、減速機１は入力軸２、出力軸３、回転子４を備える。本実施形態の入力軸２はモータ６の回転軸である。入力軸２は上下方向に棒状に延び、モータ６の駆動で軸心ＡＸを中心に回転する。以下説明では便宜上、軸方向は上下方向に沿い、図中に矢印で示す。入力軸２は先端部２Ａ、中間部２Ｂ、基端部２Ｃを有する。モータ６は入力軸２の基端部２Ｃをモータ６内部にて回転可能に保持する。先端部２Ａと中間部２Ｂはモータ６の上方に突出する。先端部２Ａは径方向に段状に形成する。先端部２Ａ上部の外径は先端部２Ａ下部の外径よりも小さい。   As shown in FIGS. 1 and 2, the speed reducer 1 includes an input shaft 2, an output shaft 3, and a rotor 4. The input shaft 2 of this embodiment is a rotating shaft of the motor 6. The input shaft 2 extends in a bar shape in the vertical direction, and rotates about the axis AX by driving the motor 6. In the following description, for the sake of convenience, the axial direction is along the vertical direction and is indicated by an arrow in the figure. The input shaft 2 has a distal end portion 2A, an intermediate portion 2B, and a proximal end portion 2C. The motor 6 holds the base end 2 </ b> C of the input shaft 2 so as to be rotatable inside the motor 6. The tip portion 2A and the intermediate portion 2B protrude above the motor 6. The tip 2A is formed in a step shape in the radial direction. The outer diameter of the upper end portion 2A is smaller than the outer diameter of the lower end portion 2A.

本実施形態の出力軸３は軸受８の内輪であり、円環状を呈す。軸受８は転がり軸受である。軸受８の外輪７は円環状を呈し出力軸３を回転可能に支持する。出力軸３は入力軸２の基端部２Ｃよりも上方に位置する。出力軸３は入力軸２の軸心ＡＸと同心で入力軸２とは独立して回転する。以下説明では回転体の回転中心が軸心ＡＸと同心の時、回転体の回転中心を便宜上、軸心ＡＸとする。   The output shaft 3 of the present embodiment is an inner ring of the bearing 8 and has an annular shape. The bearing 8 is a rolling bearing. The outer ring 7 of the bearing 8 has an annular shape and supports the output shaft 3 to be rotatable. The output shaft 3 is located above the base end portion 2 </ b> C of the input shaft 2. The output shaft 3 is concentric with the axis AX of the input shaft 2 and rotates independently of the input shaft 2. In the following description, when the rotation center of the rotating body is concentric with the axis AX, the rotation center of the rotating body is referred to as an axis AX for convenience.

回転子４は入力軸２と出力軸３の間に設ける。回転子４は入力軸２の回転速度を減速して出力軸３を回転する機構である。回転子４は筐体５、偏心輪３０、軸受４０、歯車組１０、２０、錘５０、軸受６０、保持体６５を備える。筐体５は平面視円形の有底筒状で、底部中央に円形の開口部５Ａを有する。入力軸２の先端部２Ａと中間部２Ｂは開口部５Ａを挿通する。モータ６は回転子４の下側に配置し、筐体５の底部下面に螺子で固定する。入力軸２の先端部２Ａと中間部２Ｂは開口部５Ａを介し回転子４内に突出する。筐体５外周の縁部５Ｂは上方に突出し周方向に一周する。縁部５Ｂは径方向に厚みを有する。軸受８の外輪７は筐体５の縁部５Ｂ上に螺子で固定する。   The rotor 4 is provided between the input shaft 2 and the output shaft 3. The rotor 4 is a mechanism for reducing the rotational speed of the input shaft 2 and rotating the output shaft 3. The rotor 4 includes a housing 5, an eccentric ring 30, a bearing 40, gear sets 10 and 20, a weight 50, a bearing 60, and a holding body 65. The casing 5 has a bottomed cylindrical shape in plan view, and has a circular opening 5A at the center of the bottom. The tip portion 2A and the intermediate portion 2B of the input shaft 2 pass through the opening 5A. The motor 6 is disposed on the lower side of the rotor 4 and is fixed to the bottom lower surface of the housing 5 with screws. The front end portion 2A and the intermediate portion 2B of the input shaft 2 protrude into the rotor 4 through the opening 5A. The edge 5B of the outer periphery of the housing 5 protrudes upward and makes a round in the circumferential direction. The edge 5B has a thickness in the radial direction. The outer ring 7 of the bearing 8 is fixed on the edge 5B of the housing 5 with screws.

偏心輪３０は内側偏心輪３１と外側偏心輪３６を備える。図３に示す如く、内側偏心輪３１は軸方向に延びる円筒状を呈す。内側偏心輪３１の軸方向の長さは、入力軸２の先端部２Ａと中間部２Ｂの長さより若干短い。入力軸２の中間部２Ｂは内側偏心輪３１の筒穴３２内に配置する。筒穴３２の内径は中間部２Ｂの外径と略同じである。内側偏心輪３１の軸心ＢＸは軸心ＡＸに対し偏心する。内側偏心輪３１は外周面３３に螺子穴を有する。螺子穴は外周面３３と筒穴３２の内周面の間を径方向に貫通する。固定螺子３４は螺子穴に締結し、内側偏心輪３１を入力軸２の中間部２Ｂに固定する。故に内側偏心輪３１は入力軸２に接続する。入力軸２の回転時、内側偏心輪３１は入力軸２と一体に回転する。該時、内側偏心輪３１の軸心ＢＸは軸心ＡＸの周囲を公転する軌道を通る。   The eccentric ring 30 includes an inner eccentric ring 31 and an outer eccentric ring 36. As shown in FIG. 3, the inner eccentric ring 31 has a cylindrical shape extending in the axial direction. The length of the inner eccentric ring 31 in the axial direction is slightly shorter than the lengths of the front end portion 2A and the intermediate portion 2B of the input shaft 2. The intermediate portion 2 </ b> B of the input shaft 2 is disposed in the cylindrical hole 32 of the inner eccentric ring 31. The inner diameter of the cylindrical hole 32 is substantially the same as the outer diameter of the intermediate portion 2B. The axis BX of the inner eccentric ring 31 is eccentric with respect to the axis AX. The inner eccentric ring 31 has a screw hole on the outer peripheral surface 33. The screw hole penetrates between the outer peripheral surface 33 and the inner peripheral surface of the cylindrical hole 32 in the radial direction. The fixing screw 34 is fastened to the screw hole, and fixes the inner eccentric ring 31 to the intermediate portion 2B of the input shaft 2. Therefore, the inner eccentric ring 31 is connected to the input shaft 2. When the input shaft 2 rotates, the inner eccentric ring 31 rotates integrally with the input shaft 2. At this time, the axis BX of the inner eccentric ring 31 passes through a track revolving around the axis AX.

外側偏心輪３６は軸方向に延びる円筒状を呈す。外側偏心輪３６の軸方向の長さは、内側偏心輪３１の軸方向の長さと略同じである。内側偏心輪３１は外側偏心輪３６の筒穴３７内に配置する。筒穴３７の内径は内側偏心輪３１の外周面３３の外径と略同じである。外側偏心輪３６の軸心ＣＸは内側偏心輪３１の軸心ＢＸに対し偏心し、且つ軸心ＡＸに対し偏心する。外側偏心輪３６は外周面３８に螺子穴を有する。螺子穴は外周面３８と筒穴３７の内周面の間を径方向に貫通する。固定螺子３９は螺子穴に締結し、外側偏心輪３６を内側偏心輪３１に固定する。入力軸２の回転時、外側偏心輪３６は入力軸２及び内側偏心輪３１と一体に回転する。該時、外側偏心輪３６の軸心ＣＸは軸心ＡＸの周囲を公転する軌道を通る。   The outer eccentric ring 36 has a cylindrical shape extending in the axial direction. The axial length of the outer eccentric ring 36 is substantially the same as the axial length of the inner eccentric ring 31. The inner eccentric ring 31 is disposed in the cylindrical hole 37 of the outer eccentric ring 36. The inner diameter of the cylindrical hole 37 is substantially the same as the outer diameter of the outer peripheral surface 33 of the inner eccentric ring 31. The axis CX of the outer eccentric ring 36 is eccentric with respect to the axis BX of the inner eccentric ring 31 and is eccentric with respect to the axis AX. The outer eccentric ring 36 has a screw hole on the outer peripheral surface 38. The screw hole penetrates between the outer peripheral surface 38 and the inner peripheral surface of the cylindrical hole 37 in the radial direction. The fixing screw 39 is fastened to the screw hole to fix the outer eccentric ring 36 to the inner eccentric ring 31. When the input shaft 2 rotates, the outer eccentric ring 36 rotates integrally with the input shaft 2 and the inner eccentric ring 31. At this time, the axis CX of the outer eccentric ring 36 passes through a track revolving around the axis AX.

外側偏心輪３６は軸方向の下部に、外周面３８を周方向に一周する溝部３８１を有する。開環状の止め輪４１（図２参照）は溝部３８１に係合し、外周面３８よりも径方向外側に突出する。   The outer eccentric ring 36 has a groove 381 that goes around the outer circumferential surface 38 in the circumferential direction at the lower portion in the axial direction. An open annular retaining ring 41 (see FIG. 2) engages with the groove 381 and protrudes radially outward from the outer peripheral surface 38.

図１、図２に示す如く、軸受４０は円筒状の針状ころ軸受である。軸受４０の内輪は外側偏心輪３６の外周面３８に嵌合する。軸受４０の外輪は歯車組１０、２０の外歯車１６、２６に嵌合する。軸受４０の下端部は外側偏心輪３６の止め輪４１の上面に当接する。止め輪４１は軸受４０を軸方向に位置決めする。軸受４０の軸方向の長さは偏心輪３０の軸方向の略半分の長さであり、外歯車１６と外歯車２６の軸方向の厚みを足した長さに相当する。   As shown in FIGS. 1 and 2, the bearing 40 is a cylindrical needle roller bearing. The inner ring of the bearing 40 is fitted to the outer peripheral surface 38 of the outer eccentric ring 36. The outer ring of the bearing 40 is fitted to the external gears 16 and 26 of the gear sets 10 and 20. The lower end portion of the bearing 40 abuts on the upper surface of the retaining ring 41 of the outer eccentric ring 36. The retaining ring 41 positions the bearing 40 in the axial direction. The axial length of the bearing 40 is approximately half the axial direction of the eccentric 30, and corresponds to a length obtained by adding the axial thicknesses of the external gear 16 and the external gear 26.

歯車組１０、２０は筐体５内に収容し夫々、外歯車１６、２６と内歯車１１、２１を備える。歯車組２０は歯車組１０の上方に位置する。尚、各図面で各歯車の歯の図示は省略する。外歯車１６は円環状の板状を呈し、外周面に沿って径方向外向きに突出する複数の歯を備える。内歯車１１は円環状の板状を呈し、内周面に沿って径方向内向きに突出する複数の歯を備える。内歯車１１は外歯車１６の径方向外側に位置する。外歯車１６と内歯車１１は互いに噛合する。外歯車１６の外径は内歯車１１の内径よりも小さい。即ち外歯車１６の歯数は内歯車１１の歯数よりも少ない。外歯車１６の軸方向の厚みは軸受４０の軸方向の長さの略１／２である。   The gear sets 10 and 20 are accommodated in the housing 5 and include external gears 16 and 26 and internal gears 11 and 21, respectively. The gear set 20 is located above the gear set 10. In addition, illustration of the tooth | gear of each gear is abbreviate | omitted in each drawing. The external gear 16 has an annular plate shape and includes a plurality of teeth protruding radially outward along the outer peripheral surface. The internal gear 11 has an annular plate shape and includes a plurality of teeth protruding radially inward along the inner peripheral surface. The internal gear 11 is located radially outside the external gear 16. The external gear 16 and the internal gear 11 mesh with each other. The outer diameter of the external gear 16 is smaller than the inner diameter of the internal gear 11. That is, the number of teeth of the external gear 16 is smaller than the number of teeth of the internal gear 11. The axial thickness of the external gear 16 is approximately ½ of the axial length of the bearing 40.

外歯車１６の内周面は軸受４０外周面の下部に嵌合する。外歯車１６の軸心は外側偏心輪３６の軸心ＣＸと同心である。内歯車１１は筐体５の底部上面且つ縁部５Ｂ内側に螺子で固定する。内歯車１１の外径は筐体５の縁部５Ｂの内径と略同じである。内歯車１１の軸心は入力軸２の軸心ＡＸと同心である。軸心ＡＸに対し軸心ＣＸが偏心する偏心量Ａは、外歯車１６の外径の半径Ｒ１と内歯車１１の内径の半径Ｇ１（図４参照）との差分に相当する。入力軸２の回転時、軸心ＣＸは偏心量Ａの長さ分、軸心ＡＸから離れた位置を公転する。外歯車１６は軸心ＡＸの周囲を公転しつつ内歯車１１と噛合する。外歯車１６は内歯車１１と噛合いつつ、軸心ＣＸを中心に入力軸２とは独立して回転する。入力軸２が一方向に一回転した時、外歯車１６は一回公転し、且つ入力軸２の回転方向と逆方向に内歯車１１との歯数差の分だけ軸心ＣＸを中心に回転する。   The inner peripheral surface of the external gear 16 is fitted to the lower part of the outer peripheral surface of the bearing 40. The axis of the external gear 16 is concentric with the axis CX of the outer eccentric ring 36. The internal gear 11 is fixed to the upper surface of the bottom of the housing 5 and inside the edge 5B with screws. The outer diameter of the internal gear 11 is substantially the same as the inner diameter of the edge 5 </ b> B of the housing 5. The axis of the internal gear 11 is concentric with the axis AX of the input shaft 2. The amount of eccentricity A in which the axis CX is eccentric with respect to the axis AX corresponds to the difference between the radius R1 of the outer diameter of the external gear 16 and the radius G1 of the inner diameter of the internal gear 11 (see FIG. 4). When the input shaft 2 rotates, the shaft center CX revolves away from the shaft center AX by the length of the eccentric amount A. The external gear 16 meshes with the internal gear 11 while revolving around the axis AX. The external gear 16 rotates independently of the input shaft 2 around the axis CX while meshing with the internal gear 11. When the input shaft 2 rotates once in one direction, the external gear 16 revolves once and rotates around the shaft center CX by the difference in the number of teeth from the internal gear 11 in the direction opposite to the rotation direction of the input shaft 2. To do.

外歯車２６は円環状の板状を呈し、外周面に沿って径方向外向きに突出する複数の歯を備える。内歯車２１は円環状の板状を呈し、内周面に沿って径方向内向きに突出する複数の歯を備える。内歯車２１は外歯車２６の径方向外側に位置する。外歯車２６と内歯車２１は互いに噛合する。外歯車２６の外径は内歯車２１の内径よりも小さい。即ち外歯車２６の歯数は内歯車２１の歯数よりも少ない。外歯車２６の軸方向の厚みは軸受４０の軸方向の長さの略１／２である。   The external gear 26 has an annular plate shape and includes a plurality of teeth protruding radially outward along the outer peripheral surface. The internal gear 21 has an annular plate shape and includes a plurality of teeth protruding radially inward along the inner peripheral surface. The internal gear 21 is located on the radially outer side of the external gear 26. The external gear 26 and the internal gear 21 mesh with each other. The outer diameter of the outer gear 26 is smaller than the inner diameter of the inner gear 21. That is, the number of teeth of the external gear 26 is smaller than the number of teeth of the internal gear 21. The thickness of the external gear 26 in the axial direction is approximately ½ of the axial length of the bearing 40.

外歯車２６の内周面は軸受４０外周面の上部に嵌合する。外歯車２６は外歯車１６の上側に螺子止めで接合し、一体に固定する。即ち外歯車１６と外歯車２６は接合する。外歯車１６と外歯車２６は偏心輪３０及び軸受４０を介し、入力軸２の中間部２Ｂに設ける。外歯車２６の軸心は外側偏心輪３６の軸心ＣＸと同心である。外歯車２６の外径は外歯車１６の外径よりも小さい。外歯車２６の歯数は外歯車１６の歯数よりも少ない。   The inner peripheral surface of the external gear 26 is fitted to the upper portion of the outer peripheral surface of the bearing 40. The external gear 26 is joined to the upper side of the external gear 16 with screws and fixed integrally. That is, the external gear 16 and the external gear 26 are joined. The external gear 16 and the external gear 26 are provided in the intermediate portion 2 </ b> B of the input shaft 2 via the eccentric ring 30 and the bearing 40. The axis of the external gear 26 is concentric with the axis CX of the outer eccentric ring 36. The outer diameter of the external gear 26 is smaller than the outer diameter of the external gear 16. The number of teeth of the external gear 26 is smaller than the number of teeth of the external gear 16.

内歯車２１は、内歯車１１上方に内歯車１１とは非接触の状態で配置する。内歯車２１の内径は内歯車１１の内径よりも小さい。即ち内歯車２１の歯数は内歯車１１の歯数よりも少ない。内歯車２１は内側の縁部に沿って一周し、且つ上面から上方へ突出する突部２２を有する。突部２２は軸受８の内輪、即ち出力軸３の軸穴３Ａに係合し、出力軸３を位置決めする。内歯車２１は出力軸３に螺子で固定する。即ち内歯車２１は出力軸３に接続する。内歯車２１の軸心は入力軸２の軸心ＡＸと同心である。   The internal gear 21 is disposed above the internal gear 11 so as not to contact the internal gear 11. The internal diameter of the internal gear 21 is smaller than the internal diameter of the internal gear 11. That is, the number of teeth of the internal gear 21 is smaller than the number of teeth of the internal gear 11. The internal gear 21 has a protrusion 22 that goes around the inner edge and protrudes upward from the upper surface. The protrusion 22 engages with the inner ring of the bearing 8, that is, the shaft hole 3 </ b> A of the output shaft 3 to position the output shaft 3. The internal gear 21 is fixed to the output shaft 3 with screws. That is, the internal gear 21 is connected to the output shaft 3. The axis of the internal gear 21 is concentric with the axis AX of the input shaft 2.

外歯車２６は、軸心ＡＸに対し偏心量Ａで偏心する軸心ＣＸを中心に回転可能であり、且つ内歯車２１と噛合する。入力軸２の回転時、外歯車２６は軸心ＣＸを中心に外歯車１６と一体に回転する。内歯車２１は外歯車２６に従動し、軸心ＡＸを中心に出力軸３と一体に回転する。   The external gear 26 is rotatable about an axis CX that is eccentric with an eccentric amount A with respect to the axis AX, and meshes with the internal gear 21. When the input shaft 2 rotates, the external gear 26 rotates integrally with the external gear 16 about the axis CX. The internal gear 21 is driven by the external gear 26 and rotates integrally with the output shaft 3 about the axis AX.

錘５０は軸方向に厚みを有する円筒状の釣合い錘である。錘５０の内周面５１は外側偏心輪３６の外周面３８に嵌合する。錘５０は外周面５２に螺子穴を有し、螺子穴に固定螺子を締結して外側偏心輪３６に固定する。錘５０の固定位置は入力軸２の先端部２Ａ下部に対応する。即ち錘５０は偏心輪３０を介し、先端部２Ａ下部に接続する。錘５０の軸心は軸心ＣＸに対し偏心し、且つ軸心ＡＸに対し偏心する。   The weight 50 is a cylindrical counterweight having a thickness in the axial direction. The inner peripheral surface 51 of the weight 50 is fitted to the outer peripheral surface 38 of the outer eccentric ring 36. The weight 50 has a screw hole on the outer peripheral surface 52, and a fixing screw is fastened to the screw hole to be fixed to the outer eccentric ring 36. The fixed position of the weight 50 corresponds to the lower part of the distal end portion 2A of the input shaft 2. In other words, the weight 50 is connected to the lower portion of the distal end portion 2A via the eccentric ring 30. The axis of the weight 50 is eccentric with respect to the axis CX, and is eccentric with respect to the axis AX.

軸心ＡＸに対し軸心ＣＸが偏心するので、偏心輪３０、軸受４０及び外歯車１６、２６の重心位置は平面視で軸心ＡＸの位置と異なる。故に入力軸２の回転時、入力軸２は偏心輪３０、軸受４０及び外歯車１６、２６から遠心力の作用を受ける。錘５０の重心位置は軸心ＡＸの位置に対し、平面視で偏心輪３０、軸受４０及び外歯車１６、２６の重心位置と反対側に位置する。錘５０の重さは偏心輪３０、軸受４０及び外歯車１６、２６の重さと略同じ重さである。故に入力軸２の回転時、錘５０は入力軸２に作用する遠心力の不釣り合いを抑制する。   Since the axis CX is eccentric with respect to the axis AX, the positions of the centers of gravity of the eccentric 30, the bearing 40 and the external gears 16 and 26 are different from the position of the axis AX in plan view. Therefore, when the input shaft 2 rotates, the input shaft 2 receives the action of centrifugal force from the eccentric ring 30, the bearing 40 and the external gears 16 and 26. The center of gravity of the weight 50 is located on the opposite side of the center of gravity of the eccentric 30, the bearing 40, and the external gears 16 and 26 in plan view with respect to the position of the axis AX. The weight 50 has substantially the same weight as the eccentric ring 30, the bearing 40, and the external gears 16 and 26. Therefore, when the input shaft 2 rotates, the weight 50 suppresses the unbalance of centrifugal force acting on the input shaft 2.

軸受６０は円筒状の樹脂性軸受である。軸受６０の筒穴は入力軸２の先端部２Ａ上部に係合し、入力軸２を回転可能に支持する。軸受６０は入力軸２の先端部２Ａ上部を支持する。モータ６は入力軸２の基端部２Ｃを保持する。即ち軸受６０とモータ６は入力軸２の両端を支持し、入力軸２を補強する。軸受６０の下端部６１は径方向外向きに鍔状に突出する。軸受６０の下面は偏心輪３０の上面に接触又は近接する。   The bearing 60 is a cylindrical resin bearing. The cylindrical hole of the bearing 60 is engaged with the upper end portion 2A of the input shaft 2 to support the input shaft 2 rotatably. The bearing 60 supports the top end 2 </ b> A of the input shaft 2. The motor 6 holds the proximal end portion 2 </ b> C of the input shaft 2. That is, the bearing 60 and the motor 6 support both ends of the input shaft 2 and reinforce the input shaft 2. A lower end portion 61 of the bearing 60 protrudes radially outward in a bowl shape. The lower surface of the bearing 60 is in contact with or close to the upper surface of the eccentric ring 30.

保持体６５は軸受８を介し、軸受６０を筐体５に保持する。保持体６５は円筒状を呈し、上部外周面が径方向外側に突出し、上部内周面が径方向内側に突出する。保持体６５下部の外径は出力軸３の軸穴３Ａの内径と略同じである。保持体６５上部の外径は保持体６５下部の外径よりも大きい。保持体６５上部の開口部６６の内径は軸受６０の外径と略同じである。軸受６０は開口部６６に嵌合する。軸受６０の下端部６１は保持体６５上部の下面に当接し、保持体６５に対し軸受６０を位置決めする。保持体６５下部は軸方向上方から出力軸３の軸穴３Ａ内に嵌合する。保持体６５上部は出力軸３上面に当接し、出力軸３に対し保持体６５を位置決めする。保持体６５下部の開口部６７の内径は、入力軸２の回転に伴う錘５０の回転時に錘５０の外周面が通る領域よりも大きい。故に保持体６５下部は錘５０の回転範囲に干渉しない。   The holding body 65 holds the bearing 60 in the housing 5 via the bearing 8. The holding body 65 has a cylindrical shape, and the upper outer peripheral surface protrudes radially outward, and the upper inner peripheral surface protrudes radially inward. The outer diameter of the lower part of the holding body 65 is substantially the same as the inner diameter of the shaft hole 3 </ b> A of the output shaft 3. The outer diameter of the upper part of the holding body 65 is larger than the outer diameter of the lower part of the holding body 65. The inner diameter of the opening 66 above the holding body 65 is substantially the same as the outer diameter of the bearing 60. The bearing 60 is fitted into the opening 66. The lower end portion 61 of the bearing 60 is in contact with the lower surface of the upper portion of the holding body 65 and positions the bearing 60 with respect to the holding body 65. The lower part of the holding body 65 is fitted into the shaft hole 3A of the output shaft 3 from above in the axial direction. The upper part of the holding body 65 abuts on the upper surface of the output shaft 3 and positions the holding body 65 with respect to the output shaft 3. The inner diameter of the opening 67 below the holding body 65 is larger than the region through which the outer peripheral surface of the weight 50 passes when the weight 50 rotates as the input shaft 2 rotates. Therefore, the lower part of the holding body 65 does not interfere with the rotation range of the weight 50.

図４を参照し偏心輪３０が外歯車１６と内歯車１１の噛み合いを調整する動作を説明する。内側偏心輪３１は固定螺子３４を締結して入力軸２に固定した状態である。内側偏心輪３１の軸心ＢＸは入力軸２の軸心ＡＸに対し偏心する。外側偏心輪３６は固定螺子３９を緩め、内側偏心輪３１に対し回転可能にする。外側偏心輪３６の軸心ＣＸは軸心ＢＸに対し偏心する。   The operation in which the eccentric 30 adjusts the meshing between the external gear 16 and the internal gear 11 will be described with reference to FIG. The inner eccentric ring 31 is fixed to the input shaft 2 by fastening a fixing screw 34. The axis BX of the inner eccentric ring 31 is eccentric with respect to the axis AX of the input shaft 2. The outer eccentric ring 36 loosens the fixing screw 39 and makes it rotatable with respect to the inner eccentric ring 31. The axis CX of the outer eccentric ring 36 is eccentric with respect to the axis BX.

外歯車１６と内歯車１１の間隙Ｂが０でない時、作業者は外側偏心輪３６を内側偏心輪３１に対し回転する。軸心ＣＸの位置は平面視で軸心ＢＸの周囲を移動する。軸心ＡＸの位置に対する軸心ＢＸの位置は変わらない。軸心ＣＸの位置と軸心ＡＸの位置との間の長さ、即ち偏心量Ａは変化する。内歯車１１の内径の半径Ｇ１は、偏心量Ａと外歯車１６の外径の半径Ｒ１と間隙Ｂとを足した長さに相当する。故に偏心量Ａを調整し間隙Ｂが０又は０に近づく時、外歯車１６は内歯車１１と深く噛み合う状態になる。外側偏心輪３６は固定螺子３９を締結して内側偏心輪３１に固定し、外歯車１６と内歯車１１が噛み合う状態を維持する。   When the gap B between the external gear 16 and the internal gear 11 is not 0, the operator rotates the outer eccentric ring 36 relative to the inner eccentric ring 31. The position of the axis CX moves around the axis BX in plan view. The position of the axis BX with respect to the position of the axis AX does not change. The length between the position of the axial center CX and the position of the axial center AX, that is, the eccentric amount A changes. The radius G1 of the inner diameter of the internal gear 11 corresponds to the length obtained by adding the eccentric amount A, the radius R1 of the outer diameter of the external gear 16 and the gap B. Therefore, when the amount of eccentricity A is adjusted and the gap B is close to 0 or close to 0, the external gear 16 is in a state of being deeply engaged with the internal gear 11. The outer eccentric ring 36 is fastened to the inner eccentric ring 31 by fastening a fixing screw 39, and maintains a state where the outer gear 16 and the inner gear 11 are engaged with each other.

図５、図６を参照し減速機１の動作を説明する。以下説明で各部位の位置関係及び回転向きは、減速機１を平面視した場合の向きを基準とする。入力軸２、出力軸３、回転子４の回転角度を、θを用いた変数で表し、単位はラジアンを使用する。マーカＭ１は偏心輪３０上の所定の一点を示し、マーカＭ２は内歯車１１上の所定の一点を示し、マーカＭ３は外歯車１６上の所定の一点を示し、マーカＭ４は外歯車２６上の所定の一点を示し、マーカＭ５は内歯車２１上の所定の一点を示す。例えば図５に示す如く、内歯車１１と外歯車１６は噛合位置Ｔ１１、Ｔ１２で互いに噛合する。噛合位置Ｔ１１は内歯車１１における外歯車１６との噛合位置である。噛合位置Ｔ１２は外歯車１６における内歯車１１との噛合位置である。入力軸２はモータ６の駆動で軸心ＡＸを中心に時計回りにθｉｎ回転する。マーカＭ１と矢印Ｊで示す如く、偏心輪３０は軸心ＡＸを中心に時計回りにθｉｎ回転する。外歯車１６は軸心ＡＸの周囲をθｉｎ公転する。マーカＭ２で示す如く、内歯車１１は筐体５に固定するので回転しない。偏心輪３０の回転後、内歯車１１における外歯車１６との噛合位置Ｔ２１は、回転前の噛合位置Ｔ１１に対し軸心ＡＸを中心に時計回りにθｉｎに相当する歯数分移動する。即ち偏心輪３０回転後の噛合位置Ｔ２１は、回転前の噛合位置Ｔ１１に対し２πＧ１（θｉｎ／２π）＝Ｇ１・θｉｎ移動する。Ｇ１は内歯車１１の内径の半径である。   The operation of the speed reducer 1 will be described with reference to FIGS. In the following description, the positional relationship and the rotation direction of each part are based on the direction when the speed reducer 1 is viewed in plan. The rotation angle of the input shaft 2, the output shaft 3, and the rotor 4 is represented by a variable using θ, and the unit is radians. The marker M1 indicates a predetermined point on the eccentric ring 30, the marker M2 indicates a predetermined point on the internal gear 11, the marker M3 indicates a predetermined point on the external gear 16, and the marker M4 is on the external gear 26. A predetermined point is indicated, and the marker M5 indicates a predetermined point on the internal gear 21. For example, as shown in FIG. 5, the internal gear 11 and the external gear 16 mesh with each other at meshing positions T11 and T12. The meshing position T11 is a meshing position of the internal gear 11 with the external gear 16. The meshing position T12 is a meshing position of the external gear 16 with the internal gear 11. The input shaft 2 rotates θin clockwise around the axis AX by driving the motor 6. As shown by the marker M1 and the arrow J, the eccentric ring 30 rotates θin clockwise around the axis AX. The external gear 16 revolves around the axis AX by θin. As indicated by the marker M2, the internal gear 11 does not rotate because it is fixed to the housing 5. After the rotation of the eccentric wheel 30, the meshing position T21 of the internal gear 11 with the external gear 16 moves clockwise by the number of teeth corresponding to θin around the axis AX with respect to the meshing position T11 before the rotation. That is, the meshing position T21 after the rotation of the eccentric wheel 30 moves 2πG1 (θin / 2π) = G1 · θin with respect to the meshing position T11 before the rotation. G1 is the radius of the inner diameter of the internal gear 11.

外歯車１６は内歯車１１との間に半径差がある。故にマーカＭ３と矢印Ｋで示す如く、外歯車１６は公転しつつ、内歯車１１との半径差に応じた外周長さの差分を自転することで、内歯車１１との噛合を維持する。外歯車１６における内歯車１１との噛合位置Ｔ２２は、外歯車１６の自転と公転によって、回転前の噛合位置Ｔ１２に対し軸心ＣＸを中心に時計回り方向にθａに相当する歯数分移動する。外歯車１６の噛合位置Ｔ２２は、回転前の噛合位置Ｔ１２に対し２πＲ１（θａ／２π）＝Ｒ１・θａ移動する。Ｒ１は外歯車１６の外径の半径である。内歯車１１における外歯車１６との噛合位置Ｔ２１が噛合位置Ｔ１１に対し移動する長さと、外歯車１６における内歯車１１との噛合位置Ｔ２２が噛合位置Ｔ１２に対し移動する長さは、同じである。故に、
Ｇ１・θｉｎ＝Ｒ１・θａ ・・・ （１）
が成り立つ。 The external gear 16 has a radial difference from the internal gear 11. Therefore, as shown by the marker M3 and the arrow K, the external gear 16 revolves while rotating the difference in the outer peripheral length according to the radial difference from the internal gear 11, thereby maintaining the meshing with the internal gear 11. The meshing position T22 of the external gear 16 with the internal gear 11 is moved by the number of teeth corresponding to θa in the clockwise direction around the axis CX with respect to the meshing position T12 before rotation due to the rotation and revolution of the external gear 16. . The meshing position T22 of the external gear 16 moves 2πR1 (θa / 2π) = R1 · θa with respect to the meshing position T12 before the rotation. R1 is the radius of the outer diameter of the external gear 16. The length at which the meshing position T21 of the internal gear 11 with the external gear 16 moves relative to the meshing position T11 is the same as the length of the meshing position T22 of the external gear 16 with respect to the internal gear 11 relative to the meshing position T12. . Therefore,
G1 · θin = R1 · θa (1)
Holds.

図６に示す如く、入力軸２の回転前、内歯車２１と外歯車２６は夫々の噛合位置Ｔ３１、Ｔ３２で互いに噛合する。噛合位置Ｔ３１は内歯車２１における外歯車２６との噛合位置である。噛合位置Ｔ３２は外歯車２６における内歯車２１との噛合位置である。外歯車１６と外歯車２６は一体に回転する。故にマーカＭ４と矢印Ｐで示す如く、入力軸２がθｉｎ回転する間、外歯車２６は軸心ＡＸの周囲を時計回りに公転しつつ、軸心ＣＸを中心に反時計回りに自転する。回転後、外歯車２６における内歯車２１との噛合位置Ｔ４２は、回転前の噛合位置Ｔ３２に対し軸心ＣＸを中心に時計回り方向にθａに相当する歯数分移動する。即ち外歯車２６における内歯車２１との噛合位置Ｔ４２は、回転前の噛合位置Ｔ３２に対し２πＲ２（θａ／２π）＝Ｒ２・θａ移動する。Ｒ２は外歯車２６の外径の半径である。   As shown in FIG. 6, before the input shaft 2 rotates, the internal gear 21 and the external gear 26 mesh with each other at their meshing positions T31 and T32. The meshing position T31 is a meshing position of the internal gear 21 with the external gear 26. The meshing position T32 is a meshing position of the external gear 26 with the internal gear 21. The external gear 16 and the external gear 26 rotate integrally. Therefore, as indicated by the marker M4 and the arrow P, while the input shaft 2 rotates by θin, the external gear 26 revolves around the axis AX in the clockwise direction and rotates counterclockwise around the axis CX. After the rotation, the meshing position T42 of the external gear 26 with the internal gear 21 moves by the number of teeth corresponding to θa clockwise about the axis CX with respect to the meshing position T32 before the rotation. That is, the meshing position T42 of the external gear 26 with the internal gear 21 moves by 2πR2 (θa / 2π) = R2 · θa with respect to the meshing position T32 before rotation. R2 is the radius of the outer diameter of the external gear 26.

内歯車２１は外歯車２６との間に半径差がある。故にマーカＭ５と矢印Ｑで示す如く、内歯車２１は時計回りに自転することで、外歯車２６との半径差に応じた外周長さの差分を解消し、外歯車２６との噛合を維持する。内歯車２１における外歯車２６との噛合位置Ｔ４１は、内歯車２１の自転によって、回転前の噛合位置Ｔ３１に対し軸心ＡＸを中心に時計回り方向にθｂに相当する歯数分移動する。内歯車２１の噛合位置Ｔ４１は、回転前の噛合位置Ｔ３１に対し２πＧ２（θｂ／２π）＝Ｇ２・θｂ移動する。Ｇ２は内歯車２１の内径の半径である。外歯車２６における内歯車２１との噛合位置Ｔ４２が噛合位置Ｔ３２に対し移動する長さと、内歯車２１における外歯車２６との噛合位置Ｔ４１が噛合位置Ｔ３１に対し移動する長さは同じである。故に、
Ｒ２・θａ＝Ｇ２・θｂ ・・・ （２）
が成り立つ。 The internal gear 21 has a radial difference from the external gear 26. Therefore, as indicated by the marker M5 and the arrow Q, the internal gear 21 rotates clockwise, thereby eliminating the difference in the outer peripheral length corresponding to the radial difference from the external gear 26 and maintaining the meshing with the external gear 26. . The meshing position T41 of the internal gear 21 with the external gear 26 is moved by the number of teeth corresponding to θb in the clockwise direction around the axis AX with respect to the meshing position T31 before rotation by the rotation of the internal gear 21. The meshing position T41 of the internal gear 21 moves 2πG2 (θb / 2π) = G2 · θb with respect to the meshing position T31 before rotation. G2 is the radius of the inner diameter of the internal gear 21. The length that the meshing position T42 of the external gear 26 with the internal gear 21 moves with respect to the meshing position T32 is the same as the length of the meshing position T41 of the internal gear 21 with the external gear 26 that moves with respect to the meshing position T31. Therefore,
R2 · θa = G2 · θb (2)
Holds.

上記（１）、（２）式より、
θｂ＝（Ｇ１／Ｒ１）・（Ｒ２／Ｇ２）・θｉｎ ・・・ （３）
となる。上述の如く、内歯車２１は自転して外歯車２６との噛合を維持する。内歯車２１が自転する角度をθｏｕｔとする。θｏｕｔはθｉｎと、外歯車２６の公転と内歯車２１の自転による噛合位置の移動分の角度θｂとの差分である。故に、
θｏｕｔ＝θｉｎ−θｂ ・・・ （４）
が成り立つ。（３）式に（４）式を代入すると、
θｏｕｔ＝｛１−（（Ｇ１・Ｒ２）／（Ｒ１・Ｇ２））｝θｉｎ ・・・ （５）
となる。 From the above formulas (1) and (2),
θb = (G1 / R1) · (R2 / G2) · θin (3)
It becomes. As described above, the internal gear 21 rotates and maintains meshing with the external gear 26. An angle at which the internal gear 21 rotates is θout. θout is the difference between θin and the angle θb of the movement of the meshing position due to the revolution of the external gear 26 and the rotation of the internal gear 21. Therefore,
θout = θin−θb (4)
Holds. Substituting (4) into (3),
θout = {1-((G1 · R2) / (R1 · G2))} θin (5)
It becomes.

偏心輪３０の偏心量をＡとし、外歯車１６、２６と内歯車１１、２１の夫々の噛合における間隙Ｂが０であるとみなすと、
Ｒ１＋Ａ＝Ｇ１ ・・・ （６）
Ｒ２＋Ａ＝Ｇ２ ・・・ （７）
が成り立つ。（５）式に（６）、（７）式を代入すると、
θｏｕｔ＝｛（（Ｒ１−Ｒ２）Ａ）／（Ｒ１（Ｒ２＋Ａ））｝θｉｎ ・・・ （８）
となる。減速比は入力軸２の１回転あたりの出力軸３の回転数、即ちθｉｎ／θｏｕｔと定義する。（８）式を変形すると、
θｉｎ／θｏｕｔ＝｛Ｒ１（Ｒ２＋Ａ）｝／｛Ａ（Ｒ１−Ｒ２）｝ ・・・ （９）
となる。 Assuming that the eccentric amount of the eccentric ring 30 is A and that the gap B in the meshing between the external gears 16 and 26 and the internal gears 11 and 21 is 0,
R1 + A = G1 (6)
R2 + A = G2 (7)
Holds. Substituting Equations (6) and (7) into Equation (5),
θout = {((R1-R2) A) / (R1 (R2 + A))} θin (8)
It becomes. The reduction ratio is defined as the number of rotations of the output shaft 3 per rotation of the input shaft 2, that is, θin / θout. When formula (8) is transformed,
θin / θout = {R1 (R2 + A)} / {A (R1-R2)} (9)
It becomes.

減速比が１より大きい時、即ちθｉｎ／θｏｕｔ＞１の時、回転子４は入力軸２の回転速度を減速して出力軸３を回転する。該時、出力軸３の回転方向は入力軸２の回転方向と同一である。Ｒ１、Ｒ２、Ａは０より大きい値なので、θｉｎ／θｏｕｔ＞１と（９）式より、Ｒ１＞Ｒ２である。本実施形態の回転子４は入力軸２の回転速度を減速して出力軸３を回転できる。（９）式によれば（Ｒ１−Ｒ２）が０に近い値となる程θｉｎ／θｏｕｔは大きな値となる。即ち外歯車２６の外径の半径Ｒ２を外歯車１６の外径の半径Ｒ１に近付ける程、回転子４は減速比をより大きくできる。（９）式よりＲ１＝Ｒ２の時、減速比が無限大となるので回転子４は回転しない。減速比が−１より小さい時、即ちθｉｎ／θｏｕｔ＜−１の時、回転子４は入力軸２の回転速度を減速し、且つ入力軸２の回転方向とは反対方向に出力軸３を回転する。該時、Ｒ１、Ｒ２、Ａは０より大きい値なのでＲ１＜Ｒ２である。   When the reduction ratio is greater than 1, that is, when θin / θout> 1, the rotor 4 rotates the output shaft 3 by reducing the rotational speed of the input shaft 2. At this time, the rotation direction of the output shaft 3 is the same as the rotation direction of the input shaft 2. Since R1, R2, and A are values greater than 0, θ1 / θout> 1 and R1> R2 from equation (9). The rotor 4 of this embodiment can reduce the rotational speed of the input shaft 2 and rotate the output shaft 3. According to equation (9), θin / θout becomes larger as (R1−R2) becomes closer to 0. That is, the closer the outer radius R2 of the external gear 26 is to the outer radius R1 of the external gear 16, the greater the reduction ratio of the rotor 4 can be. From equation (9), when R1 = R2, the reduction ratio is infinite, so the rotor 4 does not rotate. When the reduction ratio is smaller than -1, that is, when θin / θout <-1, the rotor 4 decelerates the rotational speed of the input shaft 2 and rotates the output shaft 3 in the direction opposite to the rotational direction of the input shaft 2. To do. At this time, since R1, R2, and A are values greater than 0, R1 <R2.

以上説明の如く、減速機１は内歯車１１、２１に対する外歯車１６、２６の偏心量Ａと、外歯車１６、２６の外径の半径Ｒ１、Ｒ２とに応じた減速比を得る。減速機１は歯車組１０、２０が二組である。外歯車２６は外歯車１６の上側に接合し、軸心ＣＸを中心に回転可能である。内歯車２１は外歯車２６に従動し、軸心ＡＸを中心に出力軸３と一体に回転する。入力軸２が一回転した時、外歯車１６は内歯車１１との歯数差の分だけ軸心ＣＸを中心に回転する。減速機１は二組の歯車組１０、２０で十分な減速比を得ることができる。故に減速機１は、回転子４に波動歯車、遊星歯車等の高精度で複雑な機構を用いず、簡易な構成で、より大きな減速比を得ることができる。   As described above, the reduction gear 1 obtains a reduction ratio according to the eccentricity A of the external gears 16 and 26 with respect to the internal gears 11 and 21 and the radii R1 and R2 of the outer diameters of the external gears 16 and 26. The reduction gear 1 has two sets of gear sets 10 and 20. The external gear 26 is joined to the upper side of the external gear 16 and is rotatable about the axis CX. The internal gear 21 is driven by the external gear 26 and rotates integrally with the output shaft 3 about the axis AX. When the input shaft 2 rotates once, the external gear 16 rotates about the shaft center CX by the difference in the number of teeth from the internal gear 11. The reduction gear 1 can obtain a sufficient reduction ratio with the two gear sets 10 and 20. Therefore, the reduction gear 1 can obtain a larger reduction ratio with a simple configuration without using a highly accurate and complicated mechanism such as a wave gear or a planetary gear for the rotor 4.

減速機１は、入力軸２の先端部２Ａ下部に錘５０を接続する。錘５０の重心位置は軸心ＡＸの位置に対し、平面視で偏心輪３０、軸受４０及び外歯車１６、２６の重心位置と反対側に位置する。錘５０は、偏心輪３０の回転に伴い入力軸２に作用する遠心力の不釣り合いを抑制する。故に減速機１は入力軸２の振動を低減できる。   The speed reducer 1 connects a weight 50 to the lower part of the tip end 2 </ b> A of the input shaft 2. The center of gravity of the weight 50 is located on the opposite side of the center of gravity of the eccentric 30, the bearing 40, and the external gears 16 and 26 in plan view with respect to the position of the axis AX. The weight 50 suppresses unbalance of centrifugal force acting on the input shaft 2 as the eccentric ring 30 rotates. Therefore, the speed reducer 1 can reduce the vibration of the input shaft 2.

減速機１は軸受６０で入力軸２の先端部２Ａ上部を回転可能に支持した。故に減速機１は偏心輪３０の回転に伴う入力軸２の振動をより確実に低減できる。   The speed reducer 1 rotatably supports the upper end portion 2A of the input shaft 2 with a bearing 60. Therefore, the speed reducer 1 can more reliably reduce the vibration of the input shaft 2 accompanying the rotation of the eccentric wheel 30.

偏心輪３０は、内側偏心輪３１に外側偏心輪３６を固定する位置を変更し、入力軸２に対する外側偏心輪３６の偏心量Ａを変更できる。故に偏心輪３０は偏心量Ａを調整し、内歯車１１、２１に対し外歯車１６、２６が深く噛み合った状態にできる。減速機１は、歯車組１０、２０の隙間を減らし、回転力の伝達における損失を低減できる。   The eccentric ring 30 can change the eccentric amount A of the outer eccentric ring 36 with respect to the input shaft 2 by changing the position where the outer eccentric ring 36 is fixed to the inner eccentric ring 31. Therefore, the eccentric ring 30 can adjust the eccentric amount A so that the external gears 16 and 26 are deeply engaged with the internal gears 11 and 21. The speed reducer 1 can reduce the gap between the gear sets 10 and 20 and reduce loss in transmission of rotational force.

減速機１は偏心輪３０と外歯車１６、２６の間に軸受４０を設けた。故に減速機１は偏心輪３０に対する外歯車１６、２６の回転を円滑に行い、回転力の伝達における損失を低減できる。   The reduction gear 1 is provided with a bearing 40 between the eccentric ring 30 and the external gears 16 and 26. Therefore, the speed reducer 1 can smoothly rotate the external gears 16 and 26 with respect to the eccentric ring 30 and can reduce loss in transmission of rotational force.

本発明は上記実施形態に限定せず種々変更できる。外歯車１６の外径は外歯車２６の外径よりも小さくてもよい。該時、θｉｎ／θｏｕｔ＜−１になり、減速比は−１より小さくなる。回転子４は入力軸２の回転速度を減速し、且つ入力軸２の回転方向とは反対方向に出力軸３を回転できる。   The present invention is not limited to the above embodiment and can be variously modified. The outer diameter of the external gear 16 may be smaller than the outer diameter of the external gear 26. At this time, θin / θout <−1 and the reduction ratio becomes smaller than −1. The rotor 4 can reduce the rotational speed of the input shaft 2 and can rotate the output shaft 3 in the direction opposite to the rotational direction of the input shaft 2.

外歯車１６と外歯車２６は螺子で一体に固定したが、外歯車１６と外歯車２６を一体成形してもよい。該場合、減速機１は部品点数を減らし、回転子４の構成を簡易化できる。   Although the external gear 16 and the external gear 26 are integrally fixed with screws, the external gear 16 and the external gear 26 may be integrally formed. In this case, the speed reducer 1 can reduce the number of parts and simplify the configuration of the rotor 4.

錘５０はなくてもよい。軸受６０及び保持体６５はなくてもよい。錘５０と軸受６０及び保持体６５は何れか一方のみを設けてもよい。錘５０がなく、軸受６０及び保持体６５がある構成の時、減速機１は軸受６０で入力軸２を補強し入力軸２を細くできる。故に減速機１は偏心輪３０の径方向の大きさをなるべく小さくし且つ偏心量Ａを大きくできる。   The weight 50 may not be provided. The bearing 60 and the holding body 65 may be omitted. Only one of the weight 50, the bearing 60, and the holding body 65 may be provided. When the weight 50 is not provided and the bearing 60 and the holding body 65 are provided, the speed reducer 1 can reinforce the input shaft 2 with the bearing 60 and make the input shaft 2 thinner. Therefore, the reduction gear 1 can reduce the size of the eccentric wheel 30 in the radial direction as much as possible and increase the amount of eccentricity A.

偏心輪３０は外側偏心輪３６と内側偏心輪３１によって偏心量Ａを調整せず、予め偏心量Ａを所定の大きさに設定した一部品からなってもよい。内歯車１１、２１と外歯車１６、２６は平歯車であれば容易に製造でき好ましいが、斜歯歯車、山歯歯車等を用いてもよい。   The eccentric ring 30 may be composed of one component in which the eccentric amount A is set to a predetermined size in advance without adjusting the eccentric amount A by the outer eccentric ring 36 and the inner eccentric ring 31. The internal gears 11 and 21 and the external gears 16 and 26 can be easily manufactured as long as they are spur gears, but bevel gears, angle gears, and the like may be used.

回転子４は二組の歯車組１０、２０を備えたが、四組以上の偶数組の歯車組を備えてもよい。例えば四組の歯車組を備えた時、回転子は以下の如き構成としてもよい。一組目と二組目の歯車組の外歯車は偏心輪及び軸受を介し入力軸に設ける。二組目の歯車組の内歯車は軸心ＡＸを中心に回転可能な回転軸を固定する。三組目と四組目の歯車組の外歯車は偏心輪及び軸受を介し該回転軸に設ける。一組目と三組目の歯車組の内歯車は夫々筐体に固定する。四組目の歯車組の内歯車は出力軸に固定する。回転子の構成は歯車組が六組以上の偶数組ある場合も同様である。減速機は歯車組の組数の増加に応じて減速比をより大きくできる。   Although the rotor 4 includes the two gear sets 10 and 20, the rotor 4 may include an even number of four or more gear sets. For example, when four sets of gears are provided, the rotor may be configured as follows. The external gears of the first and second gear sets are provided on the input shaft through eccentric rings and bearings. The internal gear of the second gear set fixes a rotation shaft that can rotate about the axis AX. The external gears of the third and fourth gear sets are provided on the rotating shaft via eccentric rings and bearings. The internal gears of the first and third gear sets are each fixed to the housing. The internal gear of the fourth gear set is fixed to the output shaft. The configuration of the rotor is the same when there are an even number of gear sets of six or more. The reduction gear can increase the reduction ratio as the number of gear sets increases.

図７に示す如く、減速機１０１は減速比を変更可能な構成でもよい。減速機１０１の回転子１０４は筐体５、偏心輪１３０、軸受１４０、歯車組１１０、１２０、１７０を備える。筐体５、偏心輪１３０、軸受１４０の構成は上記実施形態の筐体５、偏心輪３０、軸受４０と略同じなので説明を省略する。歯車組１１０の外歯車１１６は軸受１４０の下部に嵌合する。歯車組１１０の内歯車１１１は筐体５の底部上面且つ縁部５Ｂ内に固定する。外歯車１１６と内歯車１１１は噛合した状態を維持する。歯車組１２０の外歯車１２６は外歯車１１６上方に位置し、外歯車１１６と一体に固定する。外歯車１２６は軸方向に外歯車１１６の二倍以上の長さを有し、上部が径方向外側に突出する。外歯車１２６の上部は外周に歯を有する歯車を構成する。外歯車１２６の下部は上部よりも外径が小さく、外周に歯を有さない。   As shown in FIG. 7, the reduction gear 101 may have a configuration in which the reduction ratio can be changed. The rotor 104 of the speed reducer 101 includes a housing 5, an eccentric ring 130, a bearing 140, and gear sets 110, 120, and 170. Since the structure of the housing | casing 5, the eccentric wheel 130, and the bearing 140 is as substantially the same as the housing | casing 5, the eccentric wheel 30, and the bearing 40 of the said embodiment, description is abbreviate | omitted. The external gear 116 of the gear set 110 is fitted to the lower part of the bearing 140. The internal gear 111 of the gear set 110 is fixed in the upper surface of the bottom of the housing 5 and in the edge 5B. The external gear 116 and the internal gear 111 maintain a meshed state. The external gear 126 of the gear set 120 is positioned above the external gear 116 and is fixed integrally with the external gear 116. The external gear 126 has a length more than twice that of the external gear 116 in the axial direction, and the upper portion protrudes radially outward. The upper part of the external gear 126 constitutes a gear having teeth on the outer periphery. The lower part of the external gear 126 has a smaller outer diameter than the upper part and does not have teeth on the outer periphery.

歯車組１７０の外歯車１７６は外歯車１２６の上に外歯車１２６と一体形成する。外歯車１１６、１２６、１７６の軸心は偏心輪１３０の軸心と同心である。外歯車１１６、１２６、１７６は、偏心輪１３０の軸心を中心に入力軸２とは独立して回転可能に設ける。外歯車１２６の歯車部分の外径は外歯車１１６の外径より大きく、外歯車１７６の外径は外歯車１１６の外径より小さい。   The external gear 176 of the gear set 170 is formed integrally with the external gear 126 on the external gear 126. The axes of the external gears 116, 126, and 176 are concentric with the axis of the eccentric ring 130. The external gears 116, 126, and 176 are provided to be rotatable independently of the input shaft 2 around the axis of the eccentric ring 130. The external diameter of the gear portion of the external gear 126 is larger than the external diameter of the external gear 116, and the external diameter of the external gear 176 is smaller than the external diameter of the external gear 116.

歯車組１７０の内歯車１７１は出力軸１０３の下に固定する。出力軸１０３は軸受１０８の内輪である。歯車組１２０の内歯車１２１は内歯車１７１の下に内歯車１７１と一体形成する。内歯車１２１は軸方向に内歯車１１１の二倍以上の長さを有し、下部が径方向内側に突出する。内歯車１２１の下部は内周に歯を有する歯車を構成する。内歯車１２１の上部は下部よりも外径が小さく、外周に歯を有さない。   The internal gear 171 of the gear set 170 is fixed below the output shaft 103. The output shaft 103 is an inner ring of the bearing 108. The internal gear 121 of the gear set 120 is integrally formed with the internal gear 171 under the internal gear 171. The internal gear 121 has a length that is at least twice that of the internal gear 111 in the axial direction, and the lower portion projects radially inward. The lower part of the internal gear 121 constitutes a gear having teeth on the inner periphery. The upper part of the internal gear 121 has a smaller outer diameter than the lower part and does not have teeth on the outer periphery.

内歯車１１１、１２１、１７１の軸心は入力軸２の軸心ＡＸと同心である。内歯車１２１、１７１は軸心ＡＸを中心に回転可能に設ける。内歯車１２１の歯車部分の内径は内歯車１１１の内径より大きく、内歯車１７１の内径は内歯車１１１の内径より小さい。軸受１０８の外輪１０７は筐体５に固定せず、軸方向に移動可能に設ける。故に出力軸１０３と内歯車１２１、１７１は軸方向に移動可能である。   The shafts of the internal gears 111, 121, and 171 are concentric with the shaft center AX of the input shaft 2. The internal gears 121 and 171 are provided to be rotatable about the axis AX. The internal diameter of the gear portion of the internal gear 121 is larger than the internal diameter of the internal gear 111, and the internal diameter of the internal gear 171 is smaller than the internal diameter of the internal gear 111. The outer ring 107 of the bearing 108 is not fixed to the housing 5 but provided to be movable in the axial direction. Therefore, the output shaft 103 and the internal gears 121 and 171 can move in the axial direction.

出力軸１０３が軸方向上方へ移動すると、内歯車１２１は外歯車１２６と噛合し、内歯車１７１は外歯車１７６との噛合状態を解除する。回転子１０４は歯車組１１０と歯車組１２０を介し、入力軸２の回転速度を減速し且つ入力軸２とは反対方向に出力軸１０３を回転する。出力軸１０３が軸方向下方へ移動すると、内歯車１２１は外歯車１２６との噛合状態を解除し、内歯車１７１は外歯車１７６と噛合する。回転子１０４は歯車組１１０と歯車組１７０を介し、入力軸２の回転速度を減速し且つ入力軸２と同方向に出力軸１０３を回転する。   When the output shaft 103 moves upward in the axial direction, the internal gear 121 meshes with the external gear 126, and the internal gear 171 releases the meshed state with the external gear 176. The rotor 104 reduces the rotational speed of the input shaft 2 through the gear set 110 and the gear set 120 and rotates the output shaft 103 in the direction opposite to the input shaft 2. When the output shaft 103 moves downward in the axial direction, the internal gear 121 releases the meshed state with the external gear 126, and the internal gear 171 meshes with the external gear 176. The rotor 104 reduces the rotational speed of the input shaft 2 and rotates the output shaft 103 in the same direction as the input shaft 2 via the gear set 110 and the gear set 170.

出力軸１０３が軸方向に移動することで、減速機１０１は歯車組１２０と歯車組１７０を択一的に歯車組１１０と接続する。歯車組１２０の外歯車１２６と歯車組１７０の外歯車１７６は外径が異なる。故に減速機１０１は減速比を変更できる。   As the output shaft 103 moves in the axial direction, the reduction gear 101 alternatively connects the gear set 120 and the gear set 170 to the gear set 110. The external gear 126 of the gear set 120 and the external gear 176 of the gear set 170 have different outer diameters. Therefore, the reduction gear 101 can change the reduction ratio.

上記実施形態の軸受６０が本発明の「支持体」に相当する。歯車組１１０が本発明の「第一歯車組」に相当し、歯車組１２０が本発明の「第二歯車組」に相当し、歯車組１７０が本発明の「第三歯車組」に相当する。   The bearing 60 of the above embodiment corresponds to the “support” of the present invention. The gear set 110 corresponds to the “first gear set” of the present invention, the gear set 120 corresponds to the “second gear set” of the present invention, and the gear set 170 corresponds to the “third gear set” of the present invention. .

１ 減速機
２ 入力軸
２Ａ 先端部
３ 出力軸
４ 回転子
５ 筐体
１０、２０、１１０、１２０、１７０ 歯車組
１１、２１ 内歯車
１６、２６ 外歯車
３０ 偏心輪
３１ 内側偏心輪
３６ 外側偏心輪
４０、６０ 軸受
５０ 錘
Ａ 偏心量
ＡＸ 軸心 DESCRIPTION OF SYMBOLS 1 Reducer 2 Input shaft 2A Tip part 3 Output shaft 4 Rotor 5 Case 10, 20, 110, 120, 170 Gear set 11, 21 Internal gear 16, 26 External gear 30 Eccentric wheel 31 Inner eccentric wheel 36 Outer eccentric wheel 40, 60 Bearing 50 Weight A Eccentricity AX Shaft center

Claims (7)

所定の軸方向の一方側に設け、前記軸方向に延びる軸心を中心に外力によって回転する入力軸と、
前記軸方向の他方側に前記軸心と同心に設け、且つ前記入力軸とは独立に回転する出力軸と、
前記入力軸と前記出力軸に連結し、前記入力軸の回転速度を減速して前記出力軸を回転する回転子と
を備えた減速機において、
前記回転子は、
前記入力軸に接続し、且つ前記入力軸の軸心に対し所定の偏心量で偏心する偏心輪と、
外歯車と、前記外歯車の径方向外側で前記外歯車に噛合し、前記外歯車より歯数が多い内歯車とを組とする少なくとも二組の歯車組と
を備え、
前記歯車組は、前記外歯車が前記偏心輪の外周に設けて前記偏心輪の回転軸を中心に回転可能で、且つ前記内歯車の軸心が前記入力軸の軸心と同心であり、
前記二組の歯車組は前記軸方向に隣接し、且つ隣り合う前記歯車組の前記外歯車同士が接合し、
接合する前記外歯車同士の外径は互いに異なり、
前記出力軸は前記軸方向の他方側に位置する前記歯車組の前記内歯車に接続すること
を特徴とする減速機。 An input shaft provided on one side in a predetermined axial direction and rotated by an external force around an axial center extending in the axial direction;
An output shaft provided concentrically with the shaft center on the other side in the axial direction, and rotating independently of the input shaft;
In a speed reducer that is connected to the input shaft and the output shaft, and includes a rotor that rotates the output shaft by reducing the rotational speed of the input shaft.
The rotor is
An eccentric wheel connected to the input shaft and eccentric with a predetermined eccentricity with respect to the axis of the input shaft;
An external gear, and at least two sets of gears that are meshed with the external gear on the outside in the radial direction of the external gear and have an internal gear with more teeth than the external gear,
In the gear set, the outer gear is provided on the outer periphery of the eccentric ring so that the outer gear can rotate around the rotation axis of the eccentric ring, and the axis of the inner gear is concentric with the axis of the input shaft,
The two gear sets are adjacent in the axial direction, and the external gears of the adjacent gear sets are joined together,
The outer diameters of the external gears to be joined are different from each other,
The output shaft is connected to the internal gear of the gear set located on the other side in the axial direction. 前記入力軸は、前記軸方向の他方側に位置する前記歯車組の前記外歯車よりも前記軸方向の他方側に延びる先端部を有し、
前記回転子は、前記先端部に接続して前記入力軸と共に回転する錘を備え、
前記錘は、前記軸方向から見て前記入力軸の軸心に対し前記偏心輪の回転中心と反対側に重心位置を有することを特徴とする請求項１に記載の減速機。 The input shaft has a tip portion that extends to the other side in the axial direction than the external gear of the gear set located on the other side in the axial direction;
The rotor includes a weight connected to the tip portion and rotating together with the input shaft,
2. The speed reducer according to claim 1, wherein the weight has a position of a center of gravity on a side opposite to a rotation center of the eccentric ring with respect to an axis of the input shaft when viewed from the axial direction. 前記回転子は、
前記歯車組を収容する筐体と、
前記筐体に設け、前記錘が回転可能な状態で前記先端部を支持する支持体と
を備えたことを特徴とする請求項２に記載の減速機。 The rotor is
A housing that houses the gear set;
The speed reducer according to claim 2, further comprising: a support body provided on the housing and supporting the tip portion in a state where the weight is rotatable. 前記入力軸は、前記軸方向の他方側に位置する前記歯車組の前記外歯車よりも前記軸方向の他方側に延びる先端部を有し、
前記回転子は、
前記歯車組を収容する筐体と、
前記筐体に設け、前記入力軸が回転可能な状態で前記先端部を支持する支持体と
を備えたことを特徴とする請求項１に記載の減速機。 The input shaft has a tip portion that extends to the other side in the axial direction than the external gear of the gear set located on the other side in the axial direction;
The rotor is
A housing that houses the gear set;
The speed reducer according to claim 1, further comprising: a support body provided on the casing and supporting the tip portion in a state where the input shaft is rotatable. 前記偏心輪は、
前記入力軸に固定し、且つ前記入力軸の軸心に対し偏心する内側偏心輪と、
前記内側偏心輪の外周側に設けて前記内側偏心輪に固定し、且つ前記内側偏心輪の軸心に対し偏心する外側偏心輪と
を備え、
前記外側偏心輪は、前記内側偏心輪に対する回転位置を変更可能であることを特徴とする請求項１から４の何れかに記載の減速機。 The eccentric ring is
An inner eccentric ring fixed to the input shaft and eccentric with respect to the axis of the input shaft;
An outer eccentric ring that is provided on the outer circumferential side of the inner eccentric ring, is fixed to the inner eccentric ring, and is eccentric with respect to the axis of the inner eccentric ring;
The reduction gear according to any one of claims 1 to 4, wherein the outer eccentric wheel is capable of changing a rotational position with respect to the inner eccentric wheel. 前記偏心輪と前記外歯車の間に軸受を備えたことを特徴とする請求項５に記載の減速機。   The speed reducer according to claim 5, further comprising a bearing between the eccentric wheel and the external gear. 前記歯車組は、
前記軸方向の一方側から他方側に向けて、第一歯車組、第二歯車組、第三歯車組を有し、
前記第二歯車組の外歯車は、前記第一歯車組の外歯車と一体に固定し、前記軸方向の長さが前記第一歯車組の外歯車よりも長く且つ前記軸方向の他方側が径方向外側に突出し、
前記第二歯車組の外歯車の外径は、前記第一歯車組の外歯車の外径と異なり、
前記第三歯車組の外歯車は、前記第二歯車組の外歯車と一体に形成し且つ前記第一歯車組の外歯車、前記第二歯車組の外歯車と異なる外径であり、
前記第三歯車組の内歯車は、前記出力軸に固定し、
前記第二歯車組の内歯車は、前記第三歯車組の内歯車と一体に形成し且つ前記出力軸及び前記第三歯車組の内歯車と前記軸方向に移動可能であり、
前記出力軸が前記軸方向の他方側に移動した時、前記第二歯車組の内歯車と前記第二歯車組の外歯車は噛合し、前記第三歯車組の内歯車と前記第三歯車組の外歯車は噛合状態を解除し、
前記出力軸が前記軸方向の一方側に移動した時、前記第二歯車組の内歯車と前記第二歯車組の外歯車は噛合状態を解除し、前記第三歯車組の内歯車と前記第三歯車組の外歯車は噛合することを特徴とする請求項１〜６の何れかに記載の減速機。 The gear set is
From one side of the axial direction to the other side, having a first gear set, a second gear set, a third gear set,
The external gear of the second gear set is fixed integrally with the external gear of the first gear set, the axial length is longer than the external gear of the first gear set, and the other side in the axial direction has a diameter. Protruding outward in the direction,
The outer diameter of the external gear of the second gear set is different from the outer diameter of the external gear of the first gear set,
The external gear of the third gear set is formed integrally with the external gear of the second gear set and has an outer diameter different from that of the external gear of the first gear set and the external gear of the second gear set,
The internal gear of the third gear set is fixed to the output shaft,
The internal gear of the second gear set is formed integrally with the internal gear of the third gear set and is movable in the axial direction with the output shaft and the internal gear of the third gear set,
When the output shaft moves to the other side in the axial direction, the internal gear of the second gear set meshes with the external gear of the second gear set, and the internal gear of the third gear set and the third gear set The external gear of the release the meshing state,
When the output shaft moves to one side in the axial direction, the internal gear of the second gear set and the external gear of the second gear set are released from meshing, and the internal gear of the third gear set and the first gear are The reduction gear according to any one of claims 1 to 6, wherein the external gear of the three-gear set meshes.

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