JP2019157891A - Wave gear device - Google Patents

Wave gear device Download PDF

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JP2019157891A
JP2019157891A JP2018040814A JP2018040814A JP2019157891A JP 2019157891 A JP2019157891 A JP 2019157891A JP 2018040814 A JP2018040814 A JP 2018040814A JP 2018040814 A JP2018040814 A JP 2018040814A JP 2019157891 A JP2019157891 A JP 2019157891A
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flexible
external gear
peripheral surface
gear
flexible external
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誉史 佐藤
Takashi Sato
誉史 佐藤
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JTEKT Corp
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JTEKT Corp
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Abstract

To regulate the come-off of a flexible bearing without imparting a special shape to the flexible bearing of a wave generator, in a wave gear device.SOLUTION: A wave gear device 1 comprises a rigid inner tooth gear 10 having inner teeth 11, a flexible outer tooth gear 20 having outer teeth 21, and a wave generator 30. The wave generator 30 includes a flexible bearing 50 arranged inside the flexible outer tooth gear 20 in a radial direction. An outer ring 70 of the flexible bearing 50 includes a first axial-direction end part 71 arranged inside an opening end part 25 of the flexible outer tooth gear 20 in the radial direction, and a first chamfered part 74 arranged at an external peripheral face 70a of the first axial-direction end part 71, and contracted in a diameter toward an end face 71a side of the first axial-direction end part 71. The flexible outer tooth gear 20 includes a protrusion 26 formed at an internal peripheral face 20b of the opening end part 25. The protrusion 26 protrudes toward the first chamfered part 74 side, and regulates the come-off of the outer ring 70.SELECTED DRAWING: Figure 2

Description

本発明は、波動歯車装置に関する。   The present invention relates to a wave gear device.

特許文献１に提案される撓み噛み合い式歯車装置では、撓み外歯歯車に、内周面側に突出する突出部が設けられている。また、撓み外歯歯車の径方向の内側に配置された、波動発生器のローラ（軸受）の外周に、前記突出部と係合する凹部を設けることにより、撓み外歯歯車とローラとの軸方向の抜け止めが達成される。   In the flexure meshing gear device proposed in Patent Document 1, the flexure external gear is provided with a projecting portion that projects toward the inner peripheral surface. Further, by providing a concave portion that engages with the protruding portion on the outer periphery of the roller (bearing) of the wave generator, which is disposed on the radially inner side of the flexible external gear, the shaft of the flexible external gear and the roller is provided. Direction prevention is achieved.

特開２０１５−１９０４８８号公報JP2015-190488A

しかしながら、特許文献１では、ローラ（軸受）の外周の軸方向半部に、凹部を形成したり、ローラの外周の軸方向中間部に凹部を形成したりする等、軸受の外周に特殊な形状を付与する必要がある。
本発明の目的は、波動発生器の可撓性軸受に特殊な形状を付与することなく、可撓性軸受の抜けを規制することができる波動歯車装置を提供することである。 However, in Patent Document 1, a special shape is formed on the outer periphery of the bearing, such as forming a recess in the axial half of the outer periphery of the roller (bearing) or forming a recess in the axial intermediate portion of the outer periphery of the roller. Must be granted.
An object of the present invention is to provide a wave gear device that can regulate the removal of a flexible bearing without giving a special shape to the flexible bearing of the wave generator.

請求項１に記載の発明は、内周面（１０ｂ）に複数の内歯（１１）を有する円筒状の剛性内歯歯車（１０）と、外周面（２０ａ）に複数の外歯（２１）を有し軸方向（Ｘ）の少なくとも一方に開口端部（２５）を有する円筒状の可撓性外歯歯車（２０）と、前記可撓性外歯歯車の内側に配置され、前記可撓性外歯歯車を楕円状に撓めて長径部分の外歯を前記剛性内歯歯車の内歯に対して噛合させて噛合位置を周方向に移動させる波動発生器（３０）と、を備え、前記波動発生器が、楕円カム（４０）と、可撓性軸受（５０）と、を含み、前記可撓性軸受が、前記楕円カムの外周面（４０ａ）に設けられる可撓性の内輪（６０）と、前記可撓性外歯歯車の径方向内側に設けられる可撓性の外輪（７０）と、前記外輪と前記内輪との間に介在するボール（８０）と、を有し、前記外輪が、前記可撓性外歯歯車の前記開口端部の径方向内側に配置された軸方向端部（７１）と、前記軸方向端部の外周面（７０ａ）に配置され前記軸方向端部の端面（７１ａ）側に向かって小径となる面取り状部（７４）と、を含み、前記可撓性外歯歯車が、前記開口端部の内周面（２０ｂ）に配置され前記面取り状部側に向けて突出し前記外輪の抜けを規制する突出部（２６）を含む、波動歯車装置（１）を提供する。   The invention according to claim 1 is a cylindrical rigid internal gear (10) having a plurality of internal teeth (11) on the inner peripheral surface (10b), and a plurality of external teeth (21) on the outer peripheral surface (20a). A cylindrical flexible external gear (20) having an open end (25) in at least one of the axial directions (X) and an inner side of the flexible external gear, the flexible A wave generator (30) that flexes the external external gear into an elliptical shape, meshes the external teeth of the long diameter portion with the internal teeth of the rigid internal gear, and moves the meshing position in the circumferential direction, The wave generator includes an elliptic cam (40) and a flexible bearing (50), and the flexible bearing is provided on a flexible inner ring (40a) provided on an outer peripheral surface (40a) of the elliptic cam. 60), a flexible outer ring (70) provided radially inward of the flexible external gear, and interposed between the outer ring and the inner ring. An axial end (71) disposed on the radially inner side of the open end of the flexible external gear, and an outer end of the flexible external gear. A chamfered portion (74) disposed on the outer peripheral surface (70a) and having a smaller diameter toward the end surface (71a) side of the axial end portion, and the flexible external gear includes the opening end portion. Provided is a wave gear device (1) including a projecting portion (26) disposed on an inner peripheral surface (20b) and projecting toward the chamfered portion to restrict the outer ring from coming off.

なお、括弧内の英数字は、後述する実施形態における対応構成要素等を表すが、このことは、むろん、本発明がそれらの実施形態に限定されるべきことを意味するものではない。以下、この項において同じ。
請求項２に記載の発明のように、請求項１において、前記突出部が、前記開口端部の前記内周面の全周に設けられていてもよい。 In addition, although the alphanumeric character in a parenthesis represents the corresponding component etc. in embodiment mentioned later, this does not mean that this invention should be limited to those embodiment as a matter of course. The same applies hereinafter.
As in the invention described in claim 2, in claim 1, the protruding portion may be provided on the entire circumference of the inner peripheral surface of the opening end.

請求項３に記載の発明のように、請求項１又は２において、通常時に、前記突出部が、前記面取り状部から離隔しており、前記抜けの規制時に、前記突出部が、前記面取り状部と軸方向に係合するように構成されていてもよい。
請求項４に記載の発明のように、請求項１〜３の何れか一項において、前記可撓性外歯歯車が、前記開口端部を軸方向の一方側のみに含み、前記可撓性外歯歯車の歯溝（Ｇ）の溝底面（ＧＢ）が、前記開口端部側に向かって小径となるクラウニング形状を有していてもよい。 As in the third aspect of the invention, in the first or second aspect, the projecting portion is separated from the chamfered portion at a normal time, and the projecting portion is the chamfered shape at the time of restricting the omission. It may be configured to engage with the portion in the axial direction.
As in the invention described in claim 4, in any one of claims 1 to 3, the flexible external gear includes the opening end on only one side in the axial direction, and the flexibility The groove bottom surface (GB) of the tooth groove (G) of the external gear may have a crowning shape with a smaller diameter toward the opening end side.

請求項１に記載の発明では、可撓性外歯歯車の開口端部の内周面に配置された突出部が、波動発生器の可撓性軸受の外輪の軸方向端部の外周面に配置された面取り状部側に向けて突出している。このため、外輪が軸方向の抜け側へ移動しようとすると、可撓性外歯歯車の突出部が、外輪の面取り状部に対して係合することで、外輪を含む可撓性軸受の抜けが規制される。外輪に通例設けられる面取り状部を用いることで、外輪に特殊な形状を付与する必要がなく、前記抜けを規制することができる。   According to the first aspect of the present invention, the protrusion disposed on the inner peripheral surface of the open end of the flexible external gear is formed on the outer peripheral surface of the axial end of the outer ring of the flexible bearing of the wave generator. It protrudes toward the arranged chamfered part. For this reason, when the outer ring tries to move toward the axial side, the protruding portion of the flexible external gear engages with the chamfered portion of the outer ring, so that the flexible bearing including the outer ring comes off. Is regulated. By using the chamfered portion that is usually provided on the outer ring, it is not necessary to give a special shape to the outer ring, and the above-mentioned omission can be regulated.

請求項２に記載の発明では、可撓性外歯歯車の開口端部において歯底側を全周にわたって肉厚を増加することができる。このため、拡径によって応力が高くなる傾向にある開口端部に発生する応力を低減することができる。
請求項３に記載の発明では、突出部と面取り状部とが軸方向に係合される抜け規制時以外の通常時では、突出部と面取り状部との干渉が抑制される。このため、前記干渉に起因して可撓性外歯歯車の開口端部の応力が増加されることを抑制することができる。 In the invention according to claim 2, the wall thickness can be increased over the entire circumference at the open end of the flexible external gear. For this reason, the stress which generate | occur | produces in the opening edge part in which a stress tends to become high by diameter expansion can be reduced.
In the invention according to the third aspect, interference between the protrusion and the chamfered portion is suppressed in a normal time other than the time when the protrusion and the chamfered portion are engaged in the axial direction. For this reason, it can suppress that the stress of the opening edge part of a flexible external gear resulting from the said interference increases.

請求項４に記載の発明では、可撓性外歯歯車が、開口端部を軸方向の一方のみに含む、いわゆるカップ型又はシルクハット型であり、回転時に、開口端部が最も引き伸ばされて引張応力が高くなる傾向にある。また、可撓性外歯歯車の歯溝の溝底面が、開口端部側に向かって小径となるクラウニング形状を有している。仮に、前記突出部を設けない場合、可撓性外歯歯車の開口端部において、歯溝の溝底面と開口端部の内周面との間の部分の肉厚が薄くなるため、前記部分での引張応力がさらに高くなる。これに対して、本発明では、開口端部の内周面に突出部を設けて開口端部の前記部分の肉厚を増大し、引張応力を低減して寿命を向上することができる。   In the invention according to claim 4, the flexible external gear is a so-called cup type or top hat type in which the open end is included in only one of the axial directions, and the open end is most stretched during rotation. Tensile stress tends to increase. Further, the groove bottom surface of the tooth groove of the flexible external gear has a crowning shape having a smaller diameter toward the opening end side. If the projecting portion is not provided, the thickness of the portion between the groove bottom surface of the tooth groove and the inner peripheral surface of the opening end portion is reduced at the opening end portion of the flexible external gear. The tensile stress at is further increased. On the other hand, in the present invention, a protrusion can be provided on the inner peripheral surface of the opening end to increase the thickness of the portion of the opening end, thereby reducing the tensile stress and improving the life.

本発明の一実施形態に係る波動歯車装置の模式的正面図である。It is a typical front view of the wave gear device concerning one embodiment of the present invention. 波動歯車装置の概略断面図である。It is a schematic sectional drawing of a wave gear apparatus. 波動歯車装置の可撓性外歯歯車及び波動発生器の要部の概略拡大断面図である。It is a general | schematic expanded sectional view of the principal part of the flexible external gear of a wave gear apparatus and a wave generator.

以下、本発明を具体化した実施形態を図面に従って説明する。
図１は、本発明の一実施形態に係る製造方法により製造された波動歯車装置１の模式的正面図であり、図２は、波動歯車装置１の概略断面図である。図１に示すように、波動歯車装置１は、剛性内歯歯車１０と、可撓性外歯歯車２０と、波動発生器３０とを備えている。 DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic front view of a wave gear device 1 manufactured by a manufacturing method according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of the wave gear device 1. As shown in FIG. 1, the wave gear device 1 includes a rigid internal gear 10, a flexible external gear 20, and a wave generator 30.

剛性内歯歯車１０は、外周面１０ａと内周面１０ｂとを有する円筒状の歯車であり、内周面１０ｂに、複数の内歯１１を有している。剛性内歯歯車１０は、剛性の高い部材、例えば金属部材で形成されている。
可撓性外歯歯車２０は、剛性内歯歯車１０の径方向の内側に配置されている。可撓性外歯歯車２０は、外周面２０ａと内周面２０ｂとを有する円筒状の歯車であり、外周面２０ａに、複数の外歯２１を有している。剛性内歯歯車１０と可撓性外歯歯車２０は、共通の中心軸Ｃを有している。 The rigid internal gear 10 is a cylindrical gear having an outer peripheral surface 10a and an inner peripheral surface 10b, and has a plurality of internal teeth 11 on the inner peripheral surface 10b. The rigid internal gear 10 is formed of a highly rigid member such as a metal member.
The flexible external gear 20 is disposed inside the rigid internal gear 10 in the radial direction. The flexible external gear 20 is a cylindrical gear having an outer peripheral surface 20a and an inner peripheral surface 20b, and has a plurality of external teeth 21 on the outer peripheral surface 20a. The rigid internal gear 10 and the flexible external gear 20 have a common central axis C.

図２に示すように、可撓性外歯歯車２０は、薄肉カップ形状の金属製の弾性体からなり、円筒部２２と、フランジ部２３とを含む。すなわち、可撓性外歯歯車２０は、いわゆるカップ型である。円筒部２２は、一方の軸方向端部２４と、他方の軸方向端部としての開口端部２５を有している。
また、円筒部２２は、外周面２２ａ（可撓性外歯歯車２０の外周面２０ａに相当）と、内周面２２ｂ（可撓性外歯歯車２０の内周面２０ｂに相当）とを有している。外歯２１は、円筒部２２の外周面２２ａにおいて、一方の軸方向端部２４から開口端部２５まで延びている。すなわち、外歯２１は、円筒部２２の軸方向Ｘの全長にわたって円筒部２２の外周面２２ａに配置されている。また、一方の軸方向端部２４の周縁部は、Ｃ面状又はＲ面状に面取りされている。 As shown in FIG. 2, the flexible external gear 20 is made of a thin cup-shaped metal elastic body, and includes a cylindrical portion 22 and a flange portion 23. That is, the flexible external gear 20 is a so-called cup type. The cylindrical portion 22 has one axial end 24 and an open end 25 as the other axial end.
The cylindrical portion 22 has an outer peripheral surface 22a (corresponding to the outer peripheral surface 20a of the flexible external gear 20) and an inner peripheral surface 22b (corresponding to the inner peripheral surface 20b of the flexible external gear 20). is doing. The external teeth 21 extend from one axial end 24 to the open end 25 on the outer peripheral surface 22 a of the cylindrical portion 22. That is, the external teeth 21 are disposed on the outer peripheral surface 22 a of the cylindrical portion 22 over the entire length in the axial direction X of the cylindrical portion 22. Further, the peripheral edge of one axial end 24 is chamfered in a C-plane shape or an R-plane shape.

図３は、可撓性外歯歯車２０及び波動発生器３０の要部の概略拡大断面図である。図３に示すように、可撓性外歯歯車２０において、外歯２１と周方向に隣接する歯溝Ｇの溝底面ＧＢが、軸方向Ｘのクラウニング形状を有している。
具体的には、溝底面ＧＢは、軸方向Ｘの中間部に配置されて軸方向Ｘにストレートに延びる非クラウニング領域である大径のストレート領域ＧＢ０と、軸方向Ｘに関してストレート領域ＧＢ０を挟んで配置されるクラウニング領域である第１傾斜領域ＧＢ１及び第２傾斜領域ＧＢ２とを含む、台形状に形成されている。 FIG. 3 is a schematic enlarged cross-sectional view of the main parts of the flexible external gear 20 and the wave generator 30. As shown in FIG. 3, in the flexible external gear 20, the groove bottom surface GB of the tooth groove G adjacent to the external tooth 21 in the circumferential direction has a crowning shape in the axial direction X.
Specifically, the groove bottom surface GB is disposed at an intermediate portion in the axial direction X and sandwiches the large-diameter straight region GB0 that is a non-crowning region extending straight in the axial direction X and the straight region GB0 with respect to the axial direction X. It is formed in a trapezoidal shape including the first inclined region GB1 and the second inclined region GB2 which are the crowning regions to be arranged.

第１傾斜領域ＧＢ１は、ストレート領域ＧＢ０から開口端部２５側に向かって小径となるように傾斜している。第２傾斜領域ＧＢ２は、ストレート領域ＧＢ０から一方の軸方向端部２４側に向かって小径となるように傾斜している。
前記クラウニング形状があることで、可撓性外歯歯車２０の開口端部２５側が拡径されるように変形された状態でも、可撓性外歯歯車２０の外歯２１が、剛性内歯歯車１０の内歯１１に対して適正に接触され得る。 The first inclined region GB1 is inclined so as to have a smaller diameter from the straight region GB0 toward the opening end 25 side. The second inclined region GB2 is inclined so as to have a smaller diameter from the straight region GB0 toward the one axial end 24 side.
Because of the crowning shape, the external teeth 21 of the flexible external gear 20 are rigid internal gears even when the opening end 25 side of the flexible external gear 20 is deformed to have a larger diameter. The ten internal teeth 11 can be properly contacted.

図２に示すように、フランジ部２３は、円筒部２２の一方の軸方向端部２４から径方向の内側に延びる。フランジ部２３には、図示しない出力軸が取り付けられる。外歯２１の歯数は、内歯１１の歯数よりも少なくされている。外歯２１の歯数と内歯１１の歯数との差（歯数差）は、例えば２である。
可撓性外歯歯車２０は、図１に示すように弾性変形することで、楕円形に撓むことができる。そして、楕円形の長軸の両端部分Ｐ１において、外歯２１と内歯１１とが噛み合った状態となり、楕円形の短軸の両端部分Ｐ２で、外歯２１と内歯１１とが離隔した状態となる。 As shown in FIG. 2, the flange portion 23 extends radially inward from one axial end 24 of the cylindrical portion 22. An output shaft (not shown) is attached to the flange portion 23. The number of teeth of the external teeth 21 is smaller than the number of teeth of the internal teeth 11. The difference (number of teeth difference) between the number of teeth of the external teeth 21 and the number of teeth of the internal teeth 11 is, for example, 2.
The flexible external gear 20 can be bent into an elliptical shape by elastic deformation as shown in FIG. Then, the outer teeth 21 and the inner teeth 11 are engaged with each other at both ends P1 of the elliptical long axis, and the outer teeth 21 and the inner teeth 11 are separated at both ends P2 of the elliptical short axis. It becomes.

図１および図２に示すように、波動発生器３０は、可撓性外歯歯車２０の円筒部２２の径方向の内側に配置されている。波動発生器３０は、非円形カムとしての楕円カム４０と、可撓性軸受５０とを含む。可撓性軸受５０は、可撓性を有し円筒部２２の径方向の内側に配置されている。楕円カム４０は、可撓性軸受５０の径方向の内側に配置されている。すなわち、楕円カム４０に、可撓性軸受５０が外嵌され、可撓性軸受５０に、可撓性外歯歯車２０の円筒部２２が外嵌されている。   As shown in FIGS. 1 and 2, the wave generator 30 is disposed inside the cylindrical portion 22 of the flexible external gear 20 in the radial direction. The wave generator 30 includes an elliptical cam 40 as a non-circular cam and a flexible bearing 50. The flexible bearing 50 has flexibility and is disposed inside the cylindrical portion 22 in the radial direction. The elliptical cam 40 is disposed inside the flexible bearing 50 in the radial direction. That is, the flexible bearing 50 is fitted on the elliptical cam 40, and the cylindrical portion 22 of the flexible external gear 20 is fitted on the flexible bearing 50.

可撓性軸受５０は、楕円カム４０の外周面４０ａに外嵌された内輪６０と、可撓性外歯歯車２０の円筒部２２に内嵌された外輪７０と、内輪６０と外輪７０との間に介在する複数のボール８０と、リテーナ９０とを含む。ボール８０は、内輪６０の外周に形成された外周軌道溝６６と外輪７０の内周に形成された内周軌道溝７６との間に介在している。ボール８０は、リテーナ９０によって互いに離隔された状態で、内輪６０と外輪７０の間に、自転及び公転可能に挟持されている。   The flexible bearing 50 includes an inner ring 60 that is externally fitted to the outer peripheral surface 40 a of the elliptical cam 40, an outer ring 70 that is internally fitted to the cylindrical portion 22 of the flexible external gear 20, and the inner ring 60 and the outer ring 70. A plurality of balls 80 interposed therebetween and a retainer 90 are included. The ball 80 is interposed between an outer peripheral raceway groove 66 formed on the outer periphery of the inner ring 60 and an inner peripheral raceway groove 76 formed on the inner periphery of the outer ring 70. The balls 80 are sandwiched between the inner ring 60 and the outer ring 70 so as to be able to rotate and revolve while being separated from each other by the retainer 90.

外輪７０は、外周面７０ａと、内周面７０ｂと、第１軸方向端部７１と、第２軸方向端部７２とを含む。外輪７０の外周面７０ａは、軸方向Ｘの中央部に配置された円筒面部７３と、第１軸方向端部７１に配置された第１面取り状部７４と、第２軸方向端部７２に配置された第２面取り状部７５とを含む。
第１軸方向端部７１は、可撓性外歯歯車２０の開口端部２５の径方向内側に配置されている。第１面取り状部７４は、第１軸方向端部７１における外周面７０ａにおいて、第１軸方向端部７１の端面７１ａ側に向かって小径となる面取り状部である。第２軸方向端部７２は、第２軸方向端部７２における外周面７０ａにおいて、第２軸方向端部７２の端面７２ａ側に向かって小径となる面取り状部である。 The outer ring 70 includes an outer peripheral surface 70 a, an inner peripheral surface 70 b, a first axial end 71, and a second axial end 72. The outer peripheral surface 70 a of the outer ring 70 is formed by a cylindrical surface portion 73 disposed at the center portion in the axial direction X, a first chamfered portion 74 disposed at the first axial end portion 71, and a second axial end portion 72. And a second chamfered portion 75 arranged.
The first axial end 71 is disposed on the radially inner side of the open end 25 of the flexible external gear 20. The first chamfered portion 74 is a chamfered portion whose diameter decreases toward the end surface 71 a side of the first axial end portion 71 on the outer peripheral surface 70 a of the first axial end portion 71. The second axial end portion 72 is a chamfered portion having a smaller diameter toward the end surface 72 a side of the second axial end portion 72 on the outer peripheral surface 70 a of the second axial end portion 72.

円筒面部７３と第１面取り状部７４とは、可撓性外歯歯車２０の歯溝Ｇの溝底面ＧＢの第１傾斜領域ＧＢ１の径方向内側に配置されている。
可撓性外歯歯車２０は、円筒部２２の開口端部２５における内周面２２ｂに設けられ、外輪７０の第１面取り状部７４側に向けて突出する突出部２６を含む。突出部２６は、開口端部２５における内周面２２ｂの全周に設けられている。突出部２６は、開口端部２５の端面２５ａ側に向かって小径となる傾斜状に縮径されている。 The cylindrical surface portion 73 and the first chamfered portion 74 are disposed on the radially inner side of the first inclined region GB1 of the groove bottom surface GB of the tooth groove G of the flexible external gear 20.
The flexible external gear 20 includes a protrusion 26 that is provided on the inner peripheral surface 22 b of the opening end 25 of the cylindrical portion 22 and protrudes toward the first chamfered portion 74 of the outer ring 70. The protruding portion 26 is provided on the entire circumference of the inner peripheral surface 22 b at the opening end portion 25. The protruding portion 26 is reduced in diameter so as to have a smaller diameter toward the end surface 25a side of the opening end portion 25.

突出部２６は、可撓性外歯歯車２０の円筒部２２からの外輪７０の抜けを規制する機能を果たす。具体的には、突出部２６は、通常時は、第１面取り状部７４から離隔しており、外輪７０の抜けを規制するときに、第１面取り状部７４と軸方向Ｘに係合するように構成されている。
可撓性軸受５０の内輪６０および外輪７０は、楕円カム４０に嵌合されていない状態では真円形状になる。楕円カム４０の楕円の長径は、真円時の内輪６０の内径より大きく設定され、楕円カム４０の楕円の短径は、真円時の内輪６０の内径より小さく設定されている。 The protrusion 26 functions to restrict the outer ring 70 from coming off from the cylindrical portion 22 of the flexible external gear 20. Specifically, the protruding portion 26 is normally separated from the first chamfered portion 74, and engages with the first chamfered portion 74 in the axial direction X when the removal of the outer ring 70 is restricted. It is configured as follows.
The inner ring 60 and the outer ring 70 of the flexible bearing 50 have a perfect circle shape when not fitted to the elliptical cam 40. The major axis of the ellipse of the elliptic cam 40 is set to be larger than the inner diameter of the inner ring 60 when it is a perfect circle, and the minor axis of the ellipse of the elliptic cam 40 is set to be smaller than the inner diameter of the inner ring 60 when it is a perfect circle.

このため、図１に示すように、内輪６０の径方向の内側に配置された楕円カム４０は、その長径部の２箇所（図２では上下２箇所）で内輪６０を径方向の外側に押圧して内輪６０を楕円形に弾性変形させる。外輪７０は、ボール８０を介して内輪６０により楕円形に弾性変形される。楕円形に弾性変形された内輪６０及び外輪７０は、楕円カム４０が回転することに伴って楕円形の長径部となる箇所が周方向に変位する。   Therefore, as shown in FIG. 1, the elliptical cam 40 disposed on the inner side in the radial direction of the inner ring 60 presses the inner ring 60 outward in the radial direction at two places of the long diameter portion (upper and lower two places in FIG. 2). Then, the inner ring 60 is elastically deformed into an elliptical shape. The outer ring 70 is elastically deformed into an oval shape by the inner ring 60 via the ball 80. The inner ring 60 and the outer ring 70 that are elastically deformed into an elliptical shape are displaced in the circumferential direction at locations where the elliptical long-diameter portion of the elliptical cam 40 rotates.

すなわち、波動発生器３０は、可撓性外歯歯車２０の周方向において１８０度位相が異なる２箇所を外周側に向けて押圧し（図１において黒塗り矢符を参照）、可撓性外歯歯車２０を楕円形に弾性変形させることにより、可撓性外歯歯車２０のなす楕円形の長軸の両端部分Ｐ１の外歯２１を内歯１１に噛合させる。
そして、波動発生器３０の回転に伴って、可撓性外歯歯車２０と剛性内歯歯車１０との噛み合わせ位置が周方向に移動する。これにより、外歯２１と内歯１１の歯数差に応じた相対回転が、可撓性外歯歯車２０と剛性内歯歯車１０との間に発生する。 In other words, the wave generator 30 presses two locations that are 180 degrees out of phase in the circumferential direction of the flexible external gear 20 toward the outer peripheral side (see black arrows in FIG. 1), By externally deforming the toothed gear 20 into an elliptical shape, the external teeth 21 of both end portions P1 of the elliptical long axis formed by the flexible externally toothed gear 20 are engaged with the internal teeth 11.
As the wave generator 30 rotates, the meshing position of the flexible external gear 20 and the rigid internal gear 10 moves in the circumferential direction. Thereby, relative rotation according to the difference in the number of teeth between the external teeth 21 and the internal teeth 11 occurs between the flexible external gear 20 and the rigid internal gear 10.

本実施形態によれば、可撓性外歯歯車２０の開口端部２５の内周面２０ｂに設けられた突出部２６が、波動発生器３０の可撓性軸受５０の外輪７０の第１軸方向端部７１の外周面７０ａに配置された第１面取り状部７４側に向けて突出している。このため、外輪７０が、第１軸方向端部７１の端面７１ａ側へ移動しようとすると、可撓性外歯歯車２０の突出部２６が、外輪７０の第１面取り状部７４に対して軸方向Ｘに係合することで、外輪７０を含む可撓性軸受５０の抜けが規制される。外輪７０に通例設けられる面取り状部７４，７５を用いることで、外輪７０に特殊な形状を付与する必要がなく、前記抜けを規制することができる。   According to the present embodiment, the protrusion 26 provided on the inner peripheral surface 20 b of the open end 25 of the flexible external gear 20 is the first shaft of the outer ring 70 of the flexible bearing 50 of the wave generator 30. It protrudes toward the first chamfered portion 74 disposed on the outer peripheral surface 70 a of the direction end portion 71. Therefore, when the outer ring 70 tries to move toward the end surface 71 a of the first axial end 71, the protruding portion 26 of the flexible external gear 20 is pivoted with respect to the first chamfered portion 74 of the outer ring 70. By engaging in the direction X, removal of the flexible bearing 50 including the outer ring 70 is restricted. By using the chamfered portions 74 and 75 that are typically provided in the outer ring 70, it is not necessary to give the outer ring 70 a special shape, and the above-described removal can be regulated.

また、突出部２６が、可撓性外歯歯車２０の開口端部２５の内周面２０ｂの全周に配置されている。このため、可撓性外歯歯車２０の開口端部２５において歯底側を全周にわたって肉厚を増加することができる。このため、拡径によって応力が高くなる傾向にある開口端部２５に発生する応力を低減することができる。
また、可撓性外歯歯車２０の突出部２６と外輪７０の第１面取り状部７４とが軸方向Ｘに係合される抜け規制時を除く通常時では、突出部２６と第１面取り状部７４との干渉が抑制される。このため、前記干渉に起因して可撓性外歯歯車２０の開口端部２５の応力が増加されることを抑制することができる。 Moreover, the protrusion part 26 is arrange | positioned at the perimeter of the internal peripheral surface 20b of the opening edge part 25 of the flexible external gear 20. FIG. For this reason, the wall thickness can be increased over the entire circumference at the open end 25 of the flexible external gear 20. For this reason, the stress which generate | occur | produces in the opening edge part 25 in which a stress tends to become high by diameter expansion can be reduced.
Further, the protrusion 26 and the first chamfered shape are normal in the normal state except when the protruding portion 26 of the flexible external gear 20 and the first chamfered portion 74 of the outer ring 70 are engaged in the axial direction X. Interference with the part 74 is suppressed. For this reason, it can suppress that the stress of the opening edge part 25 of the flexible external gear 20 resulting from the said interference increases.

また、可撓性外歯歯車２０が、開口端部２５を軸方向Ｘの一方のみに含む、いわゆるカップ型であり、回転時に、開口端部２５が最も引き伸ばされて引張応力が高くなる傾向にある。また、可撓性外歯歯車２０の歯溝Ｇの溝底面ＧＢが、開口端部２５側に向かって小径となるクラウニング形状（第１傾斜領域ＧＢ１）を有している。仮に、可撓性外歯歯車２０の開口端部２５の内周面２０ｂに、突出部２６を設けない場合、可撓性外歯歯車２０の開口端部２５において、歯溝Ｇの溝底面ＧＢと開口端部２５の内周面２０ｂとの間の部分Ｑの肉厚が薄くなるため、部分Ｑでの引張応力がさらに高くなる。これに対して、本実施形態では、開口端部２５の内周面２０ｂに突出部２６を設けて開口端部２５の部分Ｑの肉厚を増大し、引張応力を低減して寿命を向上することができる。   Further, the flexible external gear 20 is a so-called cup type in which the opening end 25 is included only in one of the axial directions X, and the opening end 25 is stretched most during rotation and the tensile stress tends to increase. is there. Further, the groove bottom surface GB of the tooth groove G of the flexible external gear 20 has a crowning shape (first inclined region GB1) having a smaller diameter toward the opening end 25 side. If the protrusion 26 is not provided on the inner peripheral surface 20b of the opening end 25 of the flexible external gear 20, the groove bottom surface GB of the tooth groove G at the opening end 25 of the flexible external gear 20 is assumed. And the thickness of the portion Q between the opening end portion 25 and the inner peripheral surface 20b of the opening end portion 25 is reduced, so that the tensile stress at the portion Q is further increased. On the other hand, in this embodiment, the protrusion 26 is provided on the inner peripheral surface 20b of the opening end 25 to increase the thickness of the portion Q of the opening end 25, thereby reducing the tensile stress and improving the life. be able to.

また、可撓性外歯歯車２０において外歯２１が円筒部２２の軸方向Ｘの全長に設けられているため、回転時に各外歯２１の歯面が受ける面圧を抑制することができる。このため、耐久性を向上することができる。また、可及的に、外歯２１の歯たけを低くすることが可能となり、小型化を達成することができる。
本発明は、前記実施形態に限定されるものではない。例えば、可撓性外歯歯車２０は、いわゆるシルクハット型（フランジ部２３が円筒部２２から径方向外側に延びるタイプ）であってもよい。また、可撓性外歯歯車２０は、軸方向Ｘの一対の端部の双方が開口端部２５とされる、いわゆるパンケーキ型であってもよい。 Moreover, since the external teeth 21 are provided in the axial direction X of the cylindrical part 22 in the flexible external gear 20, the surface pressure which the tooth surface of each external tooth 21 receives at the time of rotation can be suppressed. For this reason, durability can be improved. In addition, it is possible to reduce the tooth depth of the external teeth 21 as much as possible, thereby achieving downsizing.
The present invention is not limited to the above embodiment. For example, the flexible external gear 20 may be a so-called top hat type (a type in which the flange portion 23 extends radially outward from the cylindrical portion 22). Further, the flexible external gear 20 may be a so-called pancake type in which both of the pair of end portions in the axial direction X are open end portions 25.

また、歯溝Ｇの溝底面ＧＢにおいて、非クラウニング領域であるストレート領域ＧＢ０が無くされて、溝底面ＧＢの軸方向Ｘの全体にクラウニング（いわゆるフルクラウニング）が設けられてもよい。
また、突出部２６として、開口端部２５における内周面２０ｂの周方向に等間隔で離隔する複数の突出部が設けられてもよい。その他、本発明は、特許請求の範囲記載の範囲内で種々の変更を施すことができる。 Further, in the groove bottom surface GB of the tooth groove G, the straight region GB0 which is a non-crowning region may be eliminated, and crowning (so-called full crowning) may be provided in the entire axial direction X of the groove bottom surface GB.
Further, as the protruding portion 26, a plurality of protruding portions that are spaced apart at equal intervals in the circumferential direction of the inner peripheral surface 20b at the opening end portion 25 may be provided. In addition, the present invention can be variously modified within the scope of the claims.

１…波動歯車装置、１０…剛性内歯歯車、１０ｂ…内周面、１１…内歯、２０…可撓性外歯歯車、２０ａ…外周面、２０ｂ…内周面、２１…外歯、２５…開口端部、２６…突出部、３０…波動発生器、４０…楕円カム、４０ａ…外周面、５０…可撓性軸受、６０…内輪、７０…外輪、７０ａ…外周面、７１…第１軸方向端部、７１ａ…端面、７４…第１面取り状部、８０…ボール、Ｇ…歯溝、ＧＢ…溝底面、ＧＢ１…第１傾斜領域（クラウニング領域）、ＧＢ２…第２傾斜領域（クラウニング領域）、Ｘ…軸方向   DESCRIPTION OF SYMBOLS 1 ... Wave gear apparatus, 10 ... Rigid internal gear, 10b ... Inner peripheral surface, 11 ... Internal tooth, 20 ... Flexible external gear, 20a ... Outer peripheral surface, 20b ... Inner peripheral surface, 21 ... External tooth, 25 ...... Open end, 26 ... projection, 30 ... wave generator, 40 ... elliptical cam, 40a ... outer peripheral surface, 50 ... flexible bearing, 60 ... inner ring, 70 ... outer ring, 70a ... outer peripheral surface, 71 ... first Axial end portion, 71a ... end face, 74 ... first chamfered portion, 80 ... ball, G ... tooth groove, GB ... groove bottom, GB1 ... first inclined region (crowning region), GB2 ... second inclined region (crowning) Area), X ... axial direction

Claims (4)

内周面に複数の内歯を有する円筒状の剛性内歯歯車と、
外周面に複数の外歯を有し軸方向の少なくとも一方に開口端部を有する円筒状の可撓性外歯歯車と、
前記可撓性外歯歯車の内側に配置され、前記可撓性外歯歯車を楕円状に撓めて長径部分の外歯を前記剛性内歯歯車の内歯に対して噛合させて噛合位置を周方向に移動させる波動発生器と、を備え、
前記波動発生器が、楕円カムと、可撓性軸受と、を含み、
前記可撓性軸受が、前記楕円カムの外周面に設けられる可撓性の内輪と、前記可撓性外歯歯車の径方向内側に設けられる可撓性の外輪と、前記外輪と前記内輪との間に介在するボールと、を有し、
前記外輪が、前記可撓性外歯歯車の前記開口端部の径方向内側に配置された軸方向端部と、前記軸方向端部の外周面に配置され前記軸方向端部の端面側に向かって小径となる面取り状部と、を含み、
前記可撓性外歯歯車が、前記開口端部の内周面に配置され前記面取り状部側に向けて突出し前記外輪の抜けを規制する突出部を含む、波動歯車装置。 A cylindrical rigid internal gear having a plurality of internal teeth on the inner peripheral surface;
A cylindrical flexible external gear having a plurality of external teeth on the outer peripheral surface and having an open end in at least one of the axial directions;
It is arranged inside the flexible external gear, the flexible external gear is bent in an elliptical shape, and the external teeth of the long diameter portion are meshed with the internal teeth of the rigid internal gear to establish the meshing position. A wave generator that moves in a circumferential direction,
The wave generator includes an elliptical cam and a flexible bearing;
The flexible bearing includes a flexible inner ring provided on an outer peripheral surface of the elliptical cam, a flexible outer ring provided on a radially inner side of the flexible external gear, the outer ring, and the inner ring. And a ball interposed between
The outer ring is disposed on the radially inner side of the opening end of the flexible external gear, and on the outer peripheral surface of the axial end and on the end surface of the axial end. A chamfered portion having a smaller diameter toward the
A wave gear device, wherein the flexible external gear includes a protruding portion that is disposed on an inner peripheral surface of the opening end portion and protrudes toward the chamfered portion side to restrict the outer ring from coming off. 請求項１に記載の波動歯車装置において、前記突出部が、前記開口端部の前記内周面の全周に設けられている、波動歯車装置。   2. The wave gear device according to claim 1, wherein the protruding portion is provided on the entire circumference of the inner peripheral surface of the opening end portion. 請求項１又は２に記載の波動歯車装置において、通常時に、前記突出部が、前記面取り状部から離隔しており、前記抜けの規制時に、前記突出部が、前記面取り状部と軸方向に係合するように構成されている、波動歯車装置。   3. The wave gear device according to claim 1, wherein the protruding portion is separated from the chamfered portion at a normal time, and the protruding portion is axially separated from the chamfered portion at the time of restriction of the slipping. A wave gear device configured to engage. 請求項１〜３の何れか一項に記載の波動歯車装置において、前記可撓性外歯歯車が、前記開口端部を軸方向の一方のみに含み、
前記可撓性外歯歯車の歯溝の溝底面が、前記開口端部側に向かって小径となるクラウニング形状を有している、波動歯車装置。 The wave gear device according to any one of claims 1 to 3, wherein the flexible external gear includes the opening end only in one of the axial directions.
The wave gear device, wherein a groove bottom surface of a tooth groove of the flexible external gear has a crowning shape having a smaller diameter toward the opening end side.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112524153A (en) * 2020-11-06 2021-03-19 北京工业大学 Design and machining process for flexible bearing outer ring of harmonic reducer wave generator

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112524153A (en) * 2020-11-06 2021-03-19 北京工业大学 Design and machining process for flexible bearing outer ring of harmonic reducer wave generator

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