WO2022179068A1 - 内啮合行星齿轮装置和机器人用关节装置 - Google Patents

内啮合行星齿轮装置和机器人用关节装置 Download PDF

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Publication number
WO2022179068A1
WO2022179068A1 PCT/CN2021/114700 CN2021114700W WO2022179068A1 WO 2022179068 A1 WO2022179068 A1 WO 2022179068A1 CN 2021114700 W CN2021114700 W CN 2021114700W WO 2022179068 A1 WO2022179068 A1 WO 2022179068A1
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WIPO (PCT)
Prior art keywords
planetary gear
pins
gear
rotation axis
inner pin
Prior art date
Application number
PCT/CN2021/114700
Other languages
English (en)
French (fr)
Inventor
林文捷
王刚
峯岸清次
郭子铭
伊佐地毅
Original Assignee
美的集团股份有限公司
广东极亚精机科技有限公司
广东美的制冷设备有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 美的集团股份有限公司, 广东极亚精机科技有限公司, 广东美的制冷设备有限公司 filed Critical 美的集团股份有限公司
Priority to CN202180094578.6A priority Critical patent/CN116981864A/zh
Priority to EP21927496.6A priority patent/EP4299950A4/en
Publication of WO2022179068A1 publication Critical patent/WO2022179068A1/zh
Priority to US18/238,407 priority patent/US20230398682A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J9/00—Programme-controlled manipulators
    • B25J9/10—Programme-controlled manipulators characterised by positioning means for manipulator elements
    • B25J9/102—Gears specially adapted therefor, e.g. reduction gears
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
    • F16C19/54—Systems consisting of a plurality of bearings with rolling friction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H1/00—Toothed gearings for conveying rotary motion
    • F16H1/28—Toothed gearings for conveying rotary motion with gears having orbital motion
    • F16H1/32—Toothed gearings for conveying rotary motion with gears having orbital motion in which the central axis of the gearing lies inside the periphery of an orbital gear
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
    • F16C19/22—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings
    • F16C19/34—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for both radial and axial load
    • F16C19/36—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for both radial and axial load with a single row of rollers
    • F16C19/361—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for both radial and axial load with a single row of rollers with cylindrical rollers
    • F16C19/362—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for both radial and axial load with a single row of rollers with cylindrical rollers the rollers being crossed within the single row
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2361/00—Apparatus or articles in engineering in general
    • F16C2361/61—Toothed gear systems, e.g. support of pinion shafts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H1/00—Toothed gearings for conveying rotary motion
    • F16H1/28—Toothed gearings for conveying rotary motion with gears having orbital motion
    • F16H1/32—Toothed gearings for conveying rotary motion with gears having orbital motion in which the central axis of the gearing lies inside the periphery of an orbital gear
    • F16H2001/325—Toothed gearings for conveying rotary motion with gears having orbital motion in which the central axis of the gearing lies inside the periphery of an orbital gear comprising a carrier with pins guiding at least one orbital gear with circular holes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H57/00—General details of gearing
    • F16H57/04—Features relating to lubrication or cooling or heating
    • F16H57/0434—Features relating to lubrication or cooling or heating relating to lubrication supply, e.g. pumps ; Pressure control
    • F16H57/0436—Pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H57/00—General details of gearing
    • F16H57/04—Features relating to lubrication or cooling or heating
    • F16H57/048—Type of gearings to be lubricated, cooled or heated
    • F16H57/0482—Gearings with gears having orbital motion
    • F16H57/0486—Gearings with gears having orbital motion with fixed gear ratio

Definitions

  • Embodiments of the present disclosure generally relate to an internal meshing planetary gear device and a robot joint device, and more specifically, to an internal meshing planetary gear device in which a planetary gear having external teeth is arranged inside an internal gear having internal teeth, and Robot joints.
  • the internally toothed gear is configured by rotatably fitting a plurality of pins (roller pins) that form internal teeth one by one to the inner peripheral surface of a gear main body (internally toothed gear main body) that also serves as a housing.
  • a plurality of inner pin holes are formed at appropriate intervals in the circumferential direction, and inner pins and inner rollers are inserted into the inner pin holes.
  • the inner pin is connected to the bracket at one end side in the axial direction, and the bracket is rotatably supported by the housing via a crossed roller bearing.
  • This gear device can be used as a gear device in which the rotation corresponding to the rotation component of the planetary gear when the internal gear is fixed is taken out from the carrier.
  • Patent Document 1 Japanese Patent Laid-Open No. 2003-74646
  • the purpose of the embodiments of the present disclosure is to provide an internal meshing planetary gear device and a robot joint device that can be easily miniaturized.
  • An internal meshing planetary gear device includes a bearing member, an internally toothed gear, a planetary gear, a plurality of inner pins, and a plurality of sets of rolling bearings.
  • the bearing member includes an outer ring and an inner ring disposed inside the outer ring, and supports the inner ring to be rotatable relative to the outer ring about a rotation axis.
  • the internal gear has internal teeth and is fixed to the outer ring.
  • the planetary gear has external teeth partially meshed with the internal teeth.
  • the plurality of inner pins are respectively inserted into the plurality of inner pin holes formed in the planetary gear, and rotate relative to the inner gear while revolving in the inner pin holes.
  • the plurality of sets of rolling bearings hold respective inner pins of the plurality of inner pins at both sides in a direction parallel to the rotation axis with respect to the planetary gear. Each of the inner pins of the plurality of inner pins is held in the respective sets of rolling bearings in a state capable of rotating.
  • a joint device for a robot includes the internal meshing planetary gear device, a first member fixed to the outer ring, and a second member fixed to the inner ring.
  • FIG. 1 is a perspective view showing a schematic configuration of an actuator including an internal meshing planetary gear device having a basic configuration.
  • FIG. 2 is a schematic exploded perspective view of the above-mentioned internal meshing planetary gear device as seen from the output side of the rotating shaft.
  • FIG 3 is a schematic cross-sectional view of the above-mentioned internal meshing planetary gear device.
  • FIG. 4 is a cross-sectional view taken along line A1-A1 of FIG. 3 , showing the above-mentioned internal meshing planetary gear device.
  • FIG. 5A is a perspective view showing a planetary gear of the above-mentioned ring gear device as a single unit.
  • FIG. 5B is a front view showing the planetary gear of the above-mentioned internal meshing planetary gear device alone.
  • FIG. 6A is a perspective view showing the bearing member of the above-mentioned ring gear device as a single unit.
  • FIG. 6B is a front view showing the bearing member of the above-mentioned internal meshing planetary gear device as a single unit.
  • FIG. 7A is a perspective view showing the eccentric shaft of the above-mentioned ring gear device as a single unit.
  • FIG. 7B is a front view showing the eccentric shaft of the above-mentioned internal meshing planetary gear device alone.
  • FIG. 8A is a perspective view showing the support body of the above-mentioned ring gear device as a single unit.
  • FIG. 8B is a front view showing the support body of the above-mentioned internal meshing planetary gear unit as a single body.
  • FIG. 9 is an enlarged view of a region Z1 of FIG. 3 showing the above-described ring gear device.
  • FIG. 10 is a cross-sectional view taken along line B1-B1 of FIG. 3 , showing the above-mentioned internal meshing planetary gear device.
  • FIG. 11 is a schematic cross-sectional view of the internal meshing planetary gear device according to the first embodiment.
  • FIG. 12A is a schematic enlarged view of a region Z1 of FIG. 11 showing the above-described ring gear device.
  • FIG. 12B is a cross-sectional view taken along line A1-A1 of FIG. 12A , showing the above-mentioned ring gear device.
  • FIG. 13 shows the above-mentioned internal meshing planetary gear device, and is an explanatory diagram schematically showing the force acting in the state of FIG. 12A .
  • Fig. 14 is a side view of the above-mentioned internal meshing planetary gear device as viewed from the output side of the rotary shaft.
  • FIG. 15 is a side view of the above-mentioned internal meshing planetary gear device as viewed from the input side of the rotating shaft.
  • FIG. 16 is a cross-sectional view taken along line A1-A1 of FIG. 11 , showing the above-mentioned ring gear device.
  • FIG. 17 is a cross-sectional view taken along line B1-B1 of FIG. 11 , showing the above-described ring gear device.
  • FIG. 18 is an explanatory diagram showing the arrangement of the rolling bearings in the above-mentioned ring gear device.
  • 19 is a schematic cross-sectional view showing a joint device for a robot using the above-mentioned internal meshing planetary gear device.
  • FIGS. 1 to 3 The drawings referred to in the embodiments of the present disclosure are schematic drawings, and the respective ratios of the sizes and thicknesses of the structural elements in the drawings do not necessarily reflect the actual size ratios.
  • the tooth shape, size, and number of teeth of the inner teeth 21 and the outer teeth 31 in FIGS. 1 to 3 are only schematically shown for illustration, and the gist thereof is not limited to the shapes shown in the drawings.
  • the internal meshing planetary gear device 1 (hereinafter, also simply referred to as “gear device 1 ”) of the present basic structure is a gear device including an internally toothed gear 2 , a planetary gear 3 , and a plurality of inner pins 4 .
  • the planetary gears 3 are arranged inside the annular internal gear 2
  • the eccentric body bearing 5 is arranged inside the planetary gears 3 .
  • the eccentric body bearing 5 has an eccentric inner ring 51 and an eccentric outer ring 52, and the eccentric inner ring 51 rotates (eccentrically moves) around a rotation axis Ax1 (refer to FIG. 3 ) displaced from the center C1 (refer to FIG.
  • the internal meshing planetary gear device 1 further includes a bearing member 6 having an outer ring 62 and an inner ring 61 .
  • the inner ring 61 is arranged inside the outer ring 62 and is supported rotatably relative to the outer ring 62 .
  • the internally toothed gear 2 has internal teeth 21 and is fixed to the outer ring 62 .
  • the internally toothed gear 2 has an annular gear body 22 and a plurality of pins 23 .
  • the plurality of pins 23 are held on the inner peripheral surface 221 of the gear body 22 in a rotatable state to constitute the internal teeth 21 .
  • the planetary gear 3 has external teeth 31 partially meshed with the internal teeth 21 . That is, on the inner side of the internal gear 2 , the planetary gears 3 are inscribed in the internal gear 2 , and a part of the external teeth 31 and a part of the internal teeth 21 are meshed with each other.
  • Such a gear device 1 is used by taking out the rotation corresponding to the rotation component of the planetary gear 3 as, for example, the rotation of the output shaft integrated with the inner ring 61 of the bearing member 6 . Accordingly, the gear device 1 functions as a gear device having a relatively high reduction ratio with the eccentric shaft 7 as the input side and the output shaft as the output side. Therefore, in the gear device 1 of the present basic structure, the planetary gears 3 and the inner ring 61 are connected by the plurality of inner pins 4 in order to transmit the rotation corresponding to the rotation component of the planetary gears 3 to the inner ring 61 of the bearing member 6 .
  • the plurality of inner pins 4 are respectively inserted into the plurality of inner pin holes 32 formed in the planetary gear 3 , and respectively rotate relative to the inner gear 2 while revolving in the inner pin holes 32 . That is, the inner pin hole 32 has a larger diameter than the inner pin 4 , and the inner pin 4 can move so as to revolve in the inner pin hole 32 while being inserted into the inner pin hole 32 .
  • the swing component of the planetary gear 3 that is, the revolution component of the planetary gear 3 is absorbed by the loose engagement between the inner pin hole 32 of the planetary gear 3 and the inner pin 4 .
  • the plurality of inner pins 4 move so as to revolve within the plurality of inner pin holes 32 , respectively, thereby absorbing the swing component of the planetary gear 3 . Therefore, the rotation (rotational component) of the planetary gear 3 other than the swing component (revolution component) of the planetary gear 3 is transmitted to the inner ring 61 of the bearing member 6 through the plurality of inner pins 4 .
  • the inner pin 4 revolves in the inner pin hole 32 of the planetary gear 3, and the rotation of the planetary gear 3 is transmitted to the plurality of inner pins 4. Therefore, as a first related art, there is known a technique using a The inner pin 4 is the technology of the inner roller which can rotate the inner pin 4 as the axis. That is, in the first related art, the inner pin 4 is kept pressed into the inner ring 61 (or the bracket integrated with the inner ring 61 ), and when the inner pin 4 revolves in the inner pin hole 32 , the inner pin 4 It slides with respect to the inner peripheral surface 321 of the inner pin hole 32 .
  • the inner roller is used in order to reduce the loss due to the frictional resistance between the inner peripheral surface 321 of the inner pin hole 32 and the inner pin 4 .
  • the inner pin hole 32 needs to have a diameter that enables the inner pin 4 with the inner roller to revolve, and it is difficult to reduce the size of the inner pin hole 32 .
  • the miniaturization of the planetary gear 3 (in particular, the reduction in diameter) is hindered, and even the miniaturization of the entire gear device 1 is hindered.
  • the gear device 1 of the present basic structure can provide the internal meshing planetary gear device 1 which can be easily miniaturized by the following structure.
  • the gear device 1 of the present basic structure includes a bearing member 6 , an internally toothed gear 2 , a planetary gear 3 , and a plurality of inner pins 4 .
  • the bearing member 6 has an outer ring 62 and an inner ring 61 arranged inside the outer ring 62 .
  • the inner ring 61 is supported so as to be rotatable relative to the outer ring 62 .
  • the internally toothed gear 2 has internal teeth 21 and is fixed to the outer ring 62 .
  • the planetary gear 3 has external teeth 31 partially meshed with the internal teeth 21 .
  • the plurality of inner pins 4 are respectively inserted into the plurality of inner pin holes 32 formed in the planetary gear 3 and rotate relative to the inner gear 2 while revolving in the inner pin holes 32 .
  • each of the plurality of inner pins 4 is held by the inner ring 61 in a rotatable state.
  • at least a part of each of the plurality of inner pins 4 is arranged at the same position as the bearing member 6 in the axial direction of the bearing member 6 .
  • each of the plurality of inner pins 4 is held by the inner ring 61 in a rotatable state, when the inner pins 4 revolve in the inner pin holes 32 , the inner pins 4 themselves can be rotated. Therefore, loss due to frictional resistance between the inner peripheral surface 321 of the inner pin hole 32 and the inner pin 4 can be reduced without using an inner roller which is mounted on the inner pin 4 and can rotate on the inner pin 4 as an axis. Therefore, in the gear device 1 of the present basic structure, the inner rollers are not necessary, and therefore, there is an advantage that miniaturization is easy.
  • each of the plurality of inner pins 4 is arranged at the same position as the bearing member 6 in the axial direction of the bearing member 6 , the size of the gear device 1 in the axial direction of the bearing member 6 can be kept small. That is to say, in the gear unit 1 of the present basic structure, the size of the gear unit 1 in the axial direction can be reduced, compared with the structure in which the bearing member 6 and the inner pin 4 are arranged in parallel (opposed) in the axial direction of the bearing member 6 . Accordingly, it is possible to contribute to further miniaturization (thinning) of the gear device 1 .
  • the number of inner pins 4 can be increased (the number of pins) to smooth the transmission of rotation, or the inner pins can be 4 Thicken to increase strength.
  • the inner pins 4 need to revolve in the inner pin holes 32 of the planetary gears 3 , so as a second related technique, there are a plurality of inner pins 4 only supported by the inner ring 61 (or a bracket integrated with the inner ring 61 ). ) to maintain the situation.
  • the second related art it is difficult to improve the accuracy of the centering of the plurality of inner pins 4, and the poor centering may cause problems such as generation of vibration and reduction in transmission efficiency. That is, each of the plurality of inner pins 4 rotates relative to the inner gear 2 while revolving in the inner pin hole 32 , thereby transmitting the rotation component of the planetary gear 3 to the inner ring 61 of the bearing member 6 .
  • the gear device 1 of the present basic structure can provide the internal meshing planetary gear device 1 in which a problem caused by poor center alignment of the plurality of inner pins 4 is less likely to occur by the following structure.
  • the gear device 1 of the present basic structure includes an internally toothed gear 2 , a planetary gear 3 , a plurality of inner pins 4 , and a support body 8 .
  • the internally toothed gear 2 has an annular gear body 22 and a plurality of pins 23 .
  • the plurality of pins 23 are held on the inner peripheral surface 221 of the gear body 22 in a rotatable state to constitute the internal teeth 21 .
  • the planetary gear 3 has external teeth 31 partially meshed with the internal teeth 21 .
  • the plurality of inner pins 4 rotate relatively with respect to the gear body 22 while revolving in the inner pin holes 32 while being inserted into the plurality of inner pin holes 32 formed in the planetary gear 3, respectively.
  • the support body 8 is annular and supports the plurality of inner pins 4 .
  • the position of the support body 8 is regulated by bringing the outer peripheral surface 81 into contact with the plurality of pins 23 .
  • the plurality of inner pins 4 are supported by the annular support body 8, the plurality of inner pins 4 are bundled by the support body 8, and the relative deviation and inclination of the plurality of inner pins 4 can be suppressed. Then, the outer peripheral surface 81 of the support body 8 is in contact with the plurality of pins 23 , whereby the position of the support body 8 is regulated. In short, the centering of the support body 8 is performed by the plurality of pins 23 , and as a result, the centering of the plurality of inner pins 4 supported by the support body 8 is also performed by the plurality of pins 23 . Therefore, according to the gear device 1 of the present basic structure, it is easy to improve the accuracy of the alignment of the plurality of inner pins 4 , and there is an advantage that problems caused by poor alignment of the plurality of inner pins 4 are less likely to occur.
  • the gear device 1 of the present basic structure constitutes an actuator 100 together with a drive source 101 .
  • the actuator 100 of the present basic structure includes the gear device 1 and the drive source 101 .
  • the drive source 101 generates a drive force for swinging the planetary gear 3 .
  • the drive source 101 oscillates the planetary gear 3 by rotating the eccentric shaft 7 around the rotation axis Ax1.
  • the term “annular” refers to a shape such as a ring (ring) that forms a space (region) enclosed on the inside at least in plan view, and is not limited to a circle that is a perfect circle in plan view
  • the shape (annulus) may be, for example, an elliptical shape, a polygonal shape, or the like.
  • a shape having a bottom such as a cup shape is included in "annular shape” as long as its peripheral wall is annular.
  • the "free fit” refers to the state of being fitted with play (gap), and the inner pin hole 32 is a hole for the inner pin 4 to fit loosely. That is, the inner pin 4 is inserted into the inner pin hole 32 in a state in which a margin of space (gap) is secured between the inner pin 4 and the inner peripheral surface 321 of the inner pin hole 32 .
  • the diameter of at least a portion of the inner pin 4 inserted into the inner pin hole 32 is smaller (thinner) than the diameter of the inner pin hole 32 .
  • the inner pin 4 can move in the inner pin hole 32 in a state of being inserted into the inner pin hole 32 , that is, it can move relatively with respect to the center of the inner pin hole 32 . Thereby, the inner pin 4 can revolve in the inner pin hole 32.
  • a gap as a cavity, and for example, a fluid such as a liquid may be filled in the gap.
  • the "revolution" mentioned in the embodiments of the present disclosure means that an object revolves around a rotation axis other than the central axis passing through the center (center of gravity) of the object. Orbital movement. Therefore, for example, when an object rotates around an eccentric axis parallel to a central axis passing through the center (center of gravity) of the object, the object revolves around the eccentric axis as a rotation axis.
  • the inner pin 4 revolves in the inner pin hole 32 in a circle around a rotation axis passing through the center of the inner pin hole 32 .
  • one side of the rotation axis Ax1 (the left side in FIG. 3 ) is referred to as the “input side”, and the other side (the right side in FIG. 3 ) of the rotation axis Ax1 is referred to as the “output side”. side” situation.
  • rotation is imparted to the rotating body (eccentric inner ring 51) from the “input side” of the rotation axis Ax1, and the rotation of the plurality of inner pins 4 (inner ring 61) is taken out from the “output side” of the rotation axis Ax1.
  • “input side” and “output side” are merely labels given for description, and the gist thereof does not limit the positional relationship between input and output as seen from the gear device 1 .
  • the "rotation axis" referred to in the embodiments of the present disclosure refers to a virtual axis (straight line) that becomes the center of the rotational motion of the rotating body. That is, the rotation axis Ax1 is a virtual axis not accompanied by a substance.
  • the eccentric inner ring 51 rotates around the rotation axis Ax1.
  • the "internal teeth” and “external teeth” mentioned in the embodiments of the present disclosure respectively refer to a collection (group) of a plurality of "teeth” rather than a single “teeth”. That is, the internal teeth 21 of the internally toothed gear 2 are constituted by a set of a plurality of teeth arranged on the inner peripheral surface 221 of the internally toothed gear 2 (gear body 22 ). Similarly, the external teeth 31 of the planetary gears 3 are composed of a plurality of sets of teeth arranged on the outer peripheral surface of the planetary gears 3 .
  • FIG. 1 is a perspective view showing a schematic configuration of an actuator 100 including a gear device 1 .
  • a drive source 101 is schematically shown.
  • FIG. 2 is a schematic exploded perspective view of the gear device 1 as seen from the output side of the rotation shaft Ax1.
  • FIG. 3 is a schematic cross-sectional view of the gear device 1 .
  • FIG. 4 is a cross-sectional view taken along the line A1-A1 in FIG. 3 .
  • the hatching is abbreviate
  • illustration of the inner peripheral surface 221 of the gear body 22 is omitted.
  • 5A and 5B are a perspective view and a front view showing the planetary gear 3 as a single unit.
  • 6A and 6B are a perspective view and a front view showing the bearing member 6 alone.
  • 7A and 7B are a perspective view and a front view showing the eccentric shaft 7 alone.
  • 8A and 8B are a perspective view and a front view showing the support body 8 as a single body.
  • the gear device 1 of this basic structure includes an internally toothed gear 2 , a planetary gear 3 , a plurality of inner pins 4 , an eccentric body bearing 5 , a bearing member 6 , an eccentric shaft 7 , and a support body 8 .
  • the gear device 1 further includes the first bearing 91 , the second bearing 92 , and the housing 10 .
  • the internal gear 2 , the planetary gear 3 , the plurality of inner pins 4 , the eccentric body bearing 5 , the bearing member 6 , the eccentric shaft 7 , the support body 8 , etc., which are components of the gear device 1 are made of stainless steel, Metals such as cast iron, carbon steel for mechanical structures, chromium molybdenum steel, phosphor bronze or aluminum bronze.
  • the metal referred to here includes a metal subjected to surface treatment such as nitriding treatment.
  • the gear device 1 of the present basic structure includes the inscribed planetary gears 3 having a cycloid-like tooth profile.
  • the gear device 1 is used in a state where the gear body 22 of the internal gear 2 is fixed to a fixing member such as the housing 10 together with the outer ring 62 of the bearing member 6 . Thereby, with the relative rotation of the internal gear 2 and the planetary gears 3, the planetary gears 3 are rotated relative to the stationary member (the case 10 and the like).
  • the eccentric shaft 7 is taken out from the output shaft integrated with the inner ring 61 of the bearing member 6 by applying a rotational force as an input to the eccentric shaft 7 .
  • Rotational force as output That is, the gear device 1 operates with the rotation of the eccentric shaft 7 as the input rotation, and the rotation of the output shaft integrated with the inner ring 61 as the output rotation.
  • the output rotation reduced by the relatively high reduction ratio with respect to the input rotation can be obtained.
  • the drive source 101 is a power generation source such as a motor (electric motor).
  • the power generated by the drive source 101 is transmitted to the eccentric shaft 7 in the gear device 1 .
  • the drive source 101 is connected to the eccentric shaft 7 via the input shaft, and the power generated by the drive source 101 is transmitted to the eccentric shaft 7 via the input shaft. Thereby, the drive source 101 can rotate the eccentric shaft 7 .
  • the rotation axis Ax1 on the input side and the rotation axis Ax1 on the output side are on the same straight line.
  • the rotation axis Ax1 on the input side and the rotation axis Ax1 on the output side are coaxial.
  • the rotation axis Ax1 on the input side is the rotation center of the eccentric shaft 7 to which the input rotation is given
  • the rotation axis Ax1 on the output side is the rotation center of the inner ring 61 (and the output shaft) which generates the output rotation. That is, in the gear device 1, the output rotation reduced by a relatively high reduction ratio can be obtained coaxially with respect to the input rotation.
  • the internally toothed gear 2 is an annular member having internal teeth 21 .
  • the internally toothed gear 2 has at least an annular shape whose inner peripheral surface is a perfect circle in plan view.
  • Internal teeth 21 are formed on the inner peripheral surface of the annular internal gear 2 along the circumferential direction of the internal gear 2 . All of the plurality of teeth constituting the internal teeth 21 have the same shape, and are provided at equal intervals over the entire area of the inner peripheral surface of the internally toothed gear 2 in the circumferential direction. That is, the pitch circle of the inner teeth 21 is a perfect circle in plan view. The center of the pitch circle of the internal teeth 21 is on the rotation axis Ax1.
  • the internally toothed gear 2 has a predetermined thickness in the direction of the rotation axis Ax1.
  • the tooth directions of the internal teeth 21 are all parallel to the rotation axis Ax1.
  • the dimension in the tooth direction of the internal teeth 21 is slightly smaller than the thickness direction of the internal tooth gear 2 .
  • the internally toothed gear 2 has an annular (annular) gear body 22 and a plurality of pins 23 .
  • the plurality of pins 23 are held on the inner peripheral surface 221 of the gear body 22 in a rotatable state to constitute the internal teeth 21 .
  • each of the plurality of pins 23 functions as a plurality of teeth constituting the inner teeth 21 .
  • a plurality of grooves are formed in the entire area of the inner peripheral surface 221 of the gear body 22 in the circumferential direction. All of the plurality of grooves have the same shape and are provided at equal intervals.
  • the plurality of grooves are all formed in parallel to the rotation axis Ax1 over the entire length of the gear body 22 in the thickness direction.
  • the plurality of pins 23 are assembled to the gear body 22 so as to be fitted into the plurality of grooves. Each of the plurality of pins 23 is held in a state capable of rotating in the groove.
  • the gear body 22 (together with the outer ring 62 ) is fixed to the casing 10 . Therefore, a plurality of fixing holes 222 for fixing are formed in the gear body 22 .
  • the planetary gear 3 is an annular member having external teeth 31 .
  • the planetary gear 3 has at least an annular shape whose outer peripheral surface is a perfect circle in plan view.
  • external teeth 31 are formed along the circumferential direction of the planetary gear 3 .
  • All of the plurality of teeth constituting the external teeth 31 have the same shape and are provided at equal intervals over the entire area in the circumferential direction of the outer peripheral surface of the planetary gear 3 . That is, the pitch circle of the external teeth 31 is a perfect circle in plan view.
  • the center C1 of the pitch circle of the external teeth 31 is at a position deviated from the rotation axis Ax1 by the distance ⁇ L (see FIG. 4 ).
  • the planetary gear 3 has a predetermined thickness in the direction of the rotation axis Ax1.
  • the outer teeth 31 are formed over the entire length of the planetary gear 3 in the thickness direction.
  • the tooth directions of the external teeth 31 are all parallel to the rotation axis Ax1.
  • the outer teeth 31 are integrally formed with the main body of the planetary gear 3 by a single metal member.
  • the eccentric body bearing 5 and the eccentric shaft 7 are combined with the planetary gear 3 . That is, the opening part 33 opened in a circular shape is formed in the planetary gear 3 .
  • the opening portion 33 is a hole penetrating the planetary gear 3 in the thickness direction. In plan view, the center of the opening 33 is aligned with the center of the planetary gear 3 , and the inner peripheral surface of the opening 33 (the inner peripheral surface of the planetary gear 3 ) and the pitch circle of the outer teeth 31 are concentric circles.
  • the eccentric body bearing 5 is accommodated in the opening 33 of the planetary gear 3 . Furthermore, by inserting the eccentric shaft 7 into the eccentric body bearing 5 (the eccentric inner ring 51 ), the eccentric body bearing 5 and the eccentric shaft 7 are combined with the planetary gear 3 . In a state where the eccentric body bearing 5 and the eccentric shaft 7 are combined with the planetary gear 3, when the eccentric shaft 7 rotates, the planetary gear 3 swings around the rotation axis Ax1.
  • the planetary gears 3 thus constituted are arranged inside the internally toothed gears 2 .
  • the planetary gear 3 is formed to be smaller than the internal gear 2 , and the planetary gear 3 can swing inside the internal gear 2 when combined with the internal gear 2 .
  • the outer teeth 31 are formed on the outer peripheral surface of the planetary gear 3
  • the inner teeth 21 are formed on the inner peripheral surface of the inner gear 2 . Therefore, in a state where the planetary gears 3 are arranged inside the inner gear 2 , the outer teeth 31 and the inner teeth 21 face each other.
  • the pitch circle of the outer teeth 31 is one turn smaller than the pitch circle of the inner teeth 21 .
  • the center C1 of the pitch circle of the outer teeth 31 is deviated from the center (rotation axis Ax1) of the pitch circle of the inner teeth 21 by the distance ⁇ L (see FIG. 4 ) s position. Therefore, at least a part of the outer teeth 31 and the inner teeth 21 face each other with a gap therebetween, and the entire circumferential direction does not mesh with each other.
  • the planetary gear 3 swings (revolves) around the rotation axis Ax1 inside the inner gear 2 , the outer teeth 31 and the inner teeth 21 are partially meshed with each other. That is, when the planetary gear 3 swings around the rotation axis Ax1, as shown in FIG. As a result, in the gear device 1 , a part of the external teeth 31 can be meshed with a part of the internal teeth 21 .
  • the number of teeth of the internal teeth 21 in the internal gear 2 is larger than the number of teeth of the external teeth 31 of the planetary gear 3 by N (N is a positive integer).
  • N is "1”
  • the number of teeth (of the external teeth 31 ) of the planetary gear 3 is "1" more than the number of teeth of the inner toothed gear 2 (of the internal teeth 21 ).
  • Such a difference in the number of teeth of the planetary gear 3 and the internally toothed gear 2 defines the reduction ratio of the output rotation with respect to the input rotation in the gear device 1 .
  • the thickness of the planetary gear 3 is smaller than the thickness of the gear main body 22 in the internally toothed gear 2 .
  • the dimension in the tooth direction (direction parallel to the rotation axis Ax1 ) of the outer teeth 31 is smaller than the dimension in the tooth direction (direction parallel to the rotation axis Ax1 ) of the inner teeth 21 .
  • the outer teeth 31 are retracted within the range of the tooth direction of the inner teeth 21 .
  • the rotation corresponding to the rotation component of the planetary gear 3 is taken out as the rotation (output rotation) of the output shaft integrated with the inner ring 61 of the bearing member 6 . Therefore, the planetary gear 3 is connected to the inner ring 61 by the plurality of inner pins 4 .
  • a plurality of inner pin holes 32 into which the plurality of inner pins 4 are inserted are formed in the planetary gear 3 .
  • the inner pin holes 32 are provided in the same number as the inner pins 4 , and in this basic structure, as an example, 18 inner pin holes 32 and 18 inner pins 4 are each provided.
  • Each of the plurality of inner pin holes 32 is a hole that opens in a circular shape and penetrates the planetary gear 3 in the thickness direction.
  • a plurality of (18 here) inner pin holes 32 are arranged on a virtual circle concentric with the opening portion 33 at equal intervals in the circumferential direction.
  • the plurality of inner pins 4 are members that connect the planetary gear 3 and the inner ring 61 of the bearing member 6 .
  • Each of the plurality of inner pins 4 is formed in a cylindrical shape.
  • the diameters and lengths of the plurality of inner pins 4 are the same among the plurality of inner pins 4 .
  • the diameter of the inner pin 4 is one turn smaller than the diameter of the inner pin hole 32 . Thereby, the inner pin 4 is inserted into the inner pin hole 32 (refer to FIG. 4 ) in a state where a margin (clearance) of a space is secured between the inner pin 4 and the inner peripheral surface 321 of the inner pin hole 32 .
  • the bearing member 6 has an outer ring 62 and an inner ring 61 and is used to take out the output of the gear device 1 as the rotation of the inner ring 61 with respect to the outer ring 62 .
  • the bearing member 6 has a plurality of rolling elements 63 (see FIG. 3 ) in addition to the outer ring 62 and the inner ring 61 .
  • both the outer ring 62 and the inner ring 61 are annular members. Both the outer ring 62 and the inner ring 61 have an annular shape that is a perfect circle in a plan view.
  • the inner ring 61 is slightly smaller than the outer ring 62 and is arranged inside the outer ring 62 .
  • the inner diameter of the outer ring 62 is larger than the outer diameter of the inner ring 61 , a gap is generated between the inner peripheral surface of the outer ring 62 and the outer peripheral surface of the inner ring 61 .
  • the inner ring 61 has a plurality of holding holes 611 into which the plurality of inner pins 4 are respectively inserted.
  • the holding holes 611 are provided in the same number as the inner pins 4, and in this basic structure, as an example, 18 holding holes 611 are provided.
  • each of the plurality of holding holes 611 is a hole that opens in a circular shape and penetrates the inner ring 61 in the thickness direction.
  • a plurality of (here, 18) holding holes 611 are arranged at equal intervals in the circumferential direction on a virtual circle concentric with the outer circumference of the inner ring 61 .
  • the diameter of the holding hole 611 is larger than the diameter of the inner pin 4 and smaller than the diameter of the inner pin hole 32 .
  • the inner ring 61 is integrated with the output shaft, and the rotation of the inner ring 61 is taken out as the rotation of the output shaft. Therefore, a plurality of output-side mounting holes 612 (refer to FIG. 2 ) for mounting the output shaft are formed in the inner ring 61 .
  • the plurality of output-side mounting holes 612 are arranged on the inner side of the plurality of holding holes 611 , and are arranged on a virtual circle concentric with the outer circumference of the inner ring 61 .
  • the outer ring 62 is fixed to a fixing member such as the case 10 together with the gear body 22 of the internally toothed gear 2 . Therefore, a plurality of through holes 621 for fixing are formed in the outer ring 62 . Specifically, as shown in FIG. 3 , in a state where the gear body 22 is sandwiched between the outer ring 62 and the housing 10 , screws (bolts) for fixing are inserted through the through holes 621 and the fixing holes 222 of the gear body 22 . ) 60 to be fixed to the housing 10.
  • the plurality of rolling elements 63 are arranged in the gap between the outer ring 62 and the inner ring 61 .
  • the plurality of rolling elements 63 are arranged in parallel along the circumferential direction of the outer ring 62 .
  • the plurality of rolling elements 63 are all metal members of the same shape, and are provided at equal intervals over the entire area of the outer ring 62 in the circumferential direction.
  • the bearing member 6 is a crossed roller bearing. That is, the bearing member 6 has cylindrical rollers as the rolling elements 63 .
  • the axis of the cylindrical rolling element 63 has an inclination of 45 degrees with respect to a plane orthogonal to the rotation axis Ax1 , and is orthogonal to the outer circumference of the inner ring 61 .
  • a pair of rolling elements 63 adjacent to each other in the circumferential direction of the inner ring 61 are arranged in a direction whose axial direction is orthogonal to each other.
  • the bearing member 6 constituted by such a crossed roller bearing, the radial load, the load in the thrust direction (the direction along the rotation axis Ax1 ), and the bending force (bending moment load) with respect to the rotation axis Ax1 are easily received . Moreover, with the one bearing member 6, these three kinds of loads can be endured, and the required rigidity can be ensured.
  • the eccentric shaft 7 is a cylindrical member.
  • the eccentric shaft 7 has a shaft center portion 71 and an eccentric portion 72 .
  • the axial center portion 71 has at least a cylindrical shape whose outer peripheral surface is a perfect circle in plan view.
  • the center (central axis) of the shaft center portion 71 coincides with the rotation axis Ax1.
  • the eccentric portion 72 has a disk shape whose outer peripheral surface is a perfect circle in plan view at least.
  • the center (central axis) of the eccentric portion 72 coincides with the center C1 deviated from the rotation axis Ax1.
  • the distance ⁇ L see FIG.
  • the eccentric shaft 7B is caused to perform eccentric motion by the shaft center portion 71 rotating (autorotating) about the rotation axis Ax1.
  • the shaft center portion 71 and the eccentric portion 72 are integrally formed with a single metal member, thereby realizing the seamless eccentric shaft 7 .
  • the eccentric shaft 7 having such a shape is combined with the planetary gear 3 together with the eccentric body bearing 5 . Therefore, when the eccentric shaft 7 rotates in a state where the eccentric body bearing 5 and the eccentric shaft 7 are combined with the planetary gear 3, the planetary gear 3 swings around the rotation axis Ax1.
  • the eccentric shaft 7 has a through hole 73 penetrating the shaft center portion 71 in the axial direction (longitudinal direction).
  • the through-hole 73 is opened in a circular shape on both end surfaces in the axial direction of the shaft center portion 71 .
  • the center (central axis) of the through hole 73 coincides with the rotation axis Ax1.
  • cables such as power lines and signal lines can be passed through the through holes 73 .
  • a plurality of input-side mounting holes 74 (refer to FIGS. 7A and 7B ) for mounting the input shaft connected to the drive source 101 are formed in the eccentric shaft 7 .
  • the plurality of input-side mounting holes 74 are arranged on a virtual circle concentric with the through-hole 73 around the through-hole 73 on one end face in the axial direction of the shaft center portion 71 .
  • the eccentric body bearing 5 has an eccentric outer ring 52 and an eccentric inner ring 51, absorbs the rotation component of the rotation of the eccentric shaft 7, and is used to only rotate the eccentric shaft 7 other than the rotation component of the eccentric shaft 7, that is, A member that transmits the swing component (revolution component) of the eccentric shaft 7 to the planetary gear 3 .
  • the eccentric body bearing 5 has a plurality of rolling elements 53 in addition to the eccentric outer ring 52 and the eccentric inner ring 51 (see FIG. 3 ).
  • Both the eccentric outer ring 52 and the eccentric inner ring 51 are annular members. Both the eccentric outer ring 52 and the eccentric inner ring 51 have an annular shape that is a perfect circle in plan view.
  • the eccentric inner ring 51 is one turn smaller than the eccentric outer ring 52 , and is arranged inside the eccentric outer ring 52 .
  • the inner diameter of the eccentric outer ring 52 is larger than the outer diameter of the eccentric inner ring 51 , a gap is generated between the inner peripheral surface of the eccentric outer ring 52 and the outer peripheral surface of the eccentric inner ring 51 .
  • the plurality of rolling elements 53 are arranged in the gap between the eccentric outer ring 52 and the eccentric inner ring 51 .
  • the plurality of rolling elements 53 are arranged in parallel along the circumferential direction of the eccentric outer ring 52 .
  • the plurality of rolling elements 53 are all metal members of the same shape, and are arranged at equal intervals over the entire area of the eccentric outer ring 52 in the circumferential direction.
  • the eccentric body bearing 5 is constituted by a deep groove ball bearing using balls as the rolling elements 53 .
  • the inner diameter of the eccentric inner ring 51 corresponds to the outer diameter of the eccentric portion 72 in the eccentric shaft 7 .
  • the eccentric body bearing 5 is combined with the eccentric shaft 7 in a state in which the eccentric portion 72 of the eccentric shaft 7 is inserted into the eccentric inner ring 51 .
  • the outer diameter of the eccentric outer ring 52 corresponds to the inner diameter (diameter) of the opening portion 33 in the planetary gear 3 .
  • the eccentric body bearing 5 is combined with the planetary gear 3 in a state where the eccentric outer ring 52 is fitted into the opening 33 of the planetary gear 3 . In other words, the eccentric body bearing 5 in a state of being attached to the eccentric portion 72 of the eccentric shaft 7 is accommodated in the opening portion 33 of the planetary gear 3 .
  • the dimension in the width direction (direction parallel to the rotation axis Ax1 ) of the eccentric inner ring 51 of the eccentric body bearing 5 is substantially the same as the thickness of the eccentric portion 72 of the eccentric shaft 7 .
  • the dimension in the width direction (direction parallel to the rotation axis Ax1 ) of the eccentric outer ring 52 is slightly smaller than the dimension in the width direction of the eccentric inner ring 51 .
  • the dimension in the width direction of the eccentric outer ring 52 is larger than the thickness of the planetary gear 3 . Therefore, the planetary gears 3 are accommodated within the range of the eccentric body bearing 5 in the direction parallel to the rotation axis Ax1.
  • the dimension in the width direction of the eccentric outer ring 52 is smaller than the dimension in the tooth direction (direction parallel to the rotation axis Ax1 ) of the inner teeth 21 . Therefore, the eccentric body bearing 5 is accommodated within the range of the internal gear 2 in the direction parallel to the rotation axis Ax1.
  • the support body 8 is formed in an annular shape and supports the plurality of inner pins 4 .
  • the support body 8 has a plurality of support holes 82 into which the plurality of inner pins 4 are inserted.
  • the support holes 82 are provided in the same number as the inner pins 4, and in this basic structure, as an example, 18 support holes 82 are provided.
  • each of the plurality of support holes 82 is a hole that opens in a circular shape and penetrates through the support body 8 in the thickness direction.
  • a plurality of (here, 18) support holes 82 are arranged at equal intervals in the circumferential direction on a virtual circle concentric with the outer peripheral surface 81 of the support body 8 .
  • the diameter of the support hole 82 is larger than the diameter of the inner pin 4 and smaller than the diameter of the inner pin hole 32 .
  • the diameter of the support hole 82 is equal to the diameter of the holding hole 611 formed in the inner ring 61.
  • the support body 8 is arrange
  • the support body 8 is explained in detail in the column of "(3.3) Support body".
  • the first bearing 91 and the second bearing 92 are respectively attached to the axial center portion 71 of the eccentric shaft 7 .
  • the first bearing 91 and the second bearing 92 are mounted on both sides of the eccentric portion 72 of the shaft center portion 71 so as to sandwich the eccentric portion 72 in a direction parallel to the rotation axis Ax1 .
  • the first bearing 91 is arranged on the input side of the rotation shaft Ax1.
  • the second bearing 92 is arranged on the output side of the rotation shaft Ax1.
  • the first bearing 91 holds the eccentric shaft 7 rotatably relative to the housing 10 .
  • the second bearing 92 holds the eccentric shaft 7 rotatably with respect to the inner ring 61 of the bearing member 6 . Thereby, the axial center portion 71 of the eccentric shaft 7 is held rotatably at two locations on both sides of the eccentric portion 72 in the direction parallel to the rotation axis Ax1.
  • the casing 10 has a cylindrical shape and has a flange portion 11 on the output side of the rotation axis Ax1.
  • a plurality of installation holes 111 for fixing the casing 10 itself are formed in the flange portion 11 .
  • a bearing hole 12 is formed in the end surface on the output side of the rotating shaft Ax1 in the housing 10 .
  • the bearing hole 12 opens in a circular shape.
  • the first bearing 91 is attached to the housing 10 by fitting the first bearing 91 into the bearing hole 12 .
  • a plurality of screw holes 13 are formed around the bearing hole 12 on the end surface on the output side of the rotating shaft Ax1 of the housing 10 .
  • the plurality of screw holes 13 are used for fixing the gear body 22 of the internally toothed gear 2 and the outer ring 62 of the bearing member 6 to the housing 10 .
  • the fixing screw 60 is passed through the through hole 621 of the outer ring 62 and the fixing hole 222 of the gear body 22 and screwed to the threaded hole 13 , thereby fixing the gear body 22 and the outer ring 62 to the case 10 .
  • the gear device 1 of the present basic structure further includes a plurality of oil seals 14 , 15 , 16 and the like.
  • the oil seal 14 is attached to the end portion on the input side of the rotating shaft Ax1 of the eccentric shaft 7 , and fills the gap between the housing 10 and the eccentric shaft 7 (axial center portion 71 ).
  • the oil seal 15 is attached to the end portion on the output side of the rotating shaft Ax1 of the eccentric shaft 7 , and fills the gap between the inner ring 61 and the eccentric shaft 7 (axial center portion 71 ).
  • the oil seal 16 is attached to the end face on the output side of the rotating shaft Ax1 of the bearing member 6 , and fills the gap between the inner ring 61 and the outer ring 62 .
  • the space sealed by the plurality of oil seals 14 , 15 and 16 constitutes the lubricant holding space 17 (see FIG. 9 ).
  • the lubricant holding space 17 includes the space between the inner ring 61 and the outer ring 62 of the bearing member 6 .
  • the plurality of pins 23 , the planetary gears 3 , the eccentric body bearing 5 , the support body 8 , the first bearing 91 , the second bearing 92 , and the like are accommodated in the lubricant holding space 17 .
  • a lubricant is enclosed in the lubricant holding space 17 .
  • the lubricant is liquid and can flow in the lubricant holding space 17 . Therefore, when the gear device 1 is used, for example, lubricant enters the meshing portion between the inner teeth 21 formed of the plurality of pins 23 and the outer teeth 31 of the planetary gear 3 .
  • the "liquid” mentioned in the embodiments of the present disclosure includes liquid or gel-like substances.
  • gelatinous as used herein refers to a state having intermediate properties between a liquid and a solid, and includes a state of a colloid composed of two phases, a liquid phase and a solid phase.
  • an emulsion in which a dispersant is a liquid phase and a dispersoid in a liquid phase, a suspension in which the dispersoid is a solid phase, and the like are referred to as a gel or a sol. shape".
  • a state in which the dispersant is in a solid phase and the dispersoid is in a liquid phase is also included in "gel-like".
  • the lubricant is a liquid lubricating oil (oil).
  • the eccentric shaft 7 rotates around the rotation axis Ax1 by applying a rotational force as an input to the eccentric shaft 7, whereby the planetary gears 3 oscillate (revolve) around the rotation axis Ax1.
  • the planetary gear 3 swings in a state in which the inner side of the inner gear 2 is inscribed with the inner gear 2 and a part of the outer teeth 31 meshes with a part of the inner teeth 21 . Therefore, the meshing positions of the inner teeth 21 and the outer teeth 31 are along the The inner gear 2 moves in the circumferential direction.
  • the difference in the number of teeth between the internal gear 2 and the planetary gear 3 defines the reduction ratio of the output rotation to the input rotation in the gear device 1 . That is, when the number of teeth of the internal gear 2 is "V1" and the number of teeth of the planetary gear 3 is "V2", the reduction ratio R1 is represented by the following formula 1.
  • the reduction ratio R1 is " 51".
  • the eccentric shaft 7 rotates once (360 degrees) clockwise around the rotation axis Ax1 when viewed from the input side of the rotation axis Ax1
  • the inner ring 61 rotates counterclockwise around the rotation axis Ax1 by a difference in the number of teeth.
  • the amount of "1" that is, about 7.06 degrees).
  • such a high reduction ratio R1 can be realized by the combination of the primary gears (the internal gear 2 and the planetary gear 3 ).
  • the gear device 1 may include at least an internally toothed gear 2 , a planetary gear 3 , a plurality of inner pins 4 , a bearing member 6 , and a support body 8 , and may also include, for example, a spline bush or the like as constituent elements.
  • the gear device 1 of the present basic structure includes the eccentric body bearing 5 which is accommodated in the opening 33 formed in the planetary gear 3 and causes the planetary gear 3 to oscillate.
  • the eccentric body bearing 5 has an eccentric outer ring 52 and an eccentric inner ring 51 arranged inside the eccentric outer ring 52 .
  • the rotating body composed of at least one of the eccentric inner ring 51 and the eccentric inner ring 51 rotating together has a gap 75 in a part on the center C1 side of the eccentric outer ring 52 .
  • the eccentric shaft 7 is "a member that rotates together with the eccentric inner ring 51", and corresponds to a “rotating body”. Therefore, the gap 75 formed in the eccentric portion 72 of the eccentric shaft 7 corresponds to the gap 75 of the rotating body.
  • the clearance 75 is located on the center C1 side when viewed from the rotation axis Ax1 , and thus functions to make the weight balance of the eccentric shaft 7 nearly equal from the rotation axis Ax1 to the circumferential direction.
  • the void 75 includes a concave portion formed on the inner peripheral surface of the through hole 73 penetrating the rotating body along the rotating axis Ax1 of the eccentric inner ring 51 . That is, in this basic structure, since the rotating body is the eccentric shaft 7 , the concave portion formed on the inner peripheral surface of the through hole 73 passing through the eccentric shaft 7 along the rotating axis Ax1 functions as the void 75 . In this way, by utilizing the recessed portion formed on the inner peripheral surface of the through hole 73 as the void 75, the weight balance of the rotating body can be achieved without accompanying a change in the appearance.
  • FIG. 9 is an enlarged view of the region Z1 of FIG. 3 .
  • the plurality of inner pins 4 are members that connect the planetary gears 3 and the inner ring 61 of the bearing member 6 . Specifically, one end portion in the longitudinal direction of the inner pin 4 (in this basic structure, the end portion on the input side of the rotation shaft Ax1 ) is inserted into the inner pin hole 32 of the planetary gear 3 , and the other end portion in the longitudinal direction of the inner pin 4 (in the In this basic structure, the output side end portion of the rotary shaft Ax1 is inserted into the holding hole 611 of the inner ring 61 .
  • the diameter of the inner pin 4 is smaller than the diameter of the inner pin hole 32, a gap can be secured between the inner pin 4 and the inner peripheral surface 321 of the inner pin hole 32, and the inner pin 4 can move in the inner pin hole 32, that is, the inner pin 4 is relatively movable with respect to the center of the inner pin hole 32.
  • the diameter of the holding hole 611 is larger than the diameter of the inner pin 4 , it is smaller than the diameter of the inner pin hole 32 .
  • the diameter of the holding hole 611 is substantially the same as the diameter of the inner pin 4 and slightly larger than the diameter of the inner pin 4 .
  • the movement of the inner pin 4 within the holding hole 611 is restricted, that is, the relative movement of the inner pin 4 with respect to the center of the holding hole 611 is prohibited. Therefore, the inner pin 4 is held in the planetary gear 3 in a state capable of revolving in the inner pin hole 32 , and is held in a state in which it cannot revolve in the holding hole 611 with respect to the inner ring 61 .
  • the swing component of the planetary gear 3 that is, the revolution component of the planetary gear 3 is absorbed by the loose engagement between the inner pin hole 32 and the inner pin 4 , and the plurality of inner pins 4 remove the swing component (revolution component) of the planetary gear 3 .
  • the rotation (rotation component) of the outer planetary gear 3 is transmitted to the inner ring 61 .
  • the diameter of the inner pin 4 is slightly larger than that of the holding hole 611 , so that the inner pin 4 in the state of being inserted into the holding hole 611 is prohibited from revolving in the holding hole 611 , but can be inserted into the holding hole 611 .
  • Rotation within 611 That is, even if the inner pin 4 is inserted into the holding hole 611 , it can rotate in the holding hole 611 because it is not pressed into the holding hole 611 .
  • each of the plurality of inner pins 4 is held by the inner ring 61 in a rotatable state. Therefore, when the inner pins 4 revolve in the inner pin holes 32 , the inner pins 4 themselves are rotatable.
  • the inner pin 4 is held relative to the planetary gear 3 in a state capable of both revolving and autorotation in the inner pin hole 32 , and is only capable of being revolved in the holding hole 611 relative to the inner ring 61 .
  • the state of rotation is maintained. That is, the plurality of inner pins 4 are rotatable (revolved) around the rotation axis Ax1 in a state in which their respective rotations are not restricted (rotatable state), and can revolve within the plurality of inner pin holes 32 .
  • the inner pins 4 can revolve and rotate in the inner pin holes 32 and can rotate in the holding holes 611 . Therefore, when the inner pin 4 revolves in the inner pin hole 32 , since the inner pin 4 is in a state capable of autorotation, it rolls with respect to the inner peripheral surface 321 of the inner pin hole 32 . In other words, since the inner pin 4 revolves in the inner pin hole 32 so as to roll on the inner peripheral surface 321 of the inner pin hole 32 , loss due to frictional resistance between the inner peripheral surface 321 of the inner pin hole 32 and the inner pin 4 is less likely to occur .
  • each of the plurality of inner pins 4 is in direct contact with the inner peripheral surface 321 of the inner pin hole 32 . That is, in this basic structure, the inner pin 4 in which the inner roller is not attached is inserted into the inner pin hole 32 so that the inner pin 4 directly contacts the inner peripheral surface 321 of the inner pin hole 32 .
  • the inner roller can be omitted and the diameter of the inner pin hole 32 can be kept relatively small, so that the planetary gear 3 can be reduced in size (in particular, the diameter), and the gear device 1 as a whole can be easily reduced in size.
  • the size of the planetary gears 3 is fixed, compared with the above-described first related art, for example, the number (number) of the inner pins 4 can be increased to smooth the transmission of rotation, or the inner pins 4 can be made thicker to increase the strength. Furthermore, the number of parts can be kept small by the amount corresponding to the inner roller, which also contributes to cost reduction of the gear device 1 .
  • each of the plurality of inner pins 4 is arranged at the same position as the bearing member 6 in the axial direction of the bearing member 6 . That is, as shown in FIG. 9 , at least a part of the inner pin 4 is arranged at the same position as the bearing member 6 in the direction parallel to the rotation axis Ax1 . In other words, at least a part of the inner pin 4 is located between both end surfaces of the bearing member 6 in the direction parallel to the rotation axis Ax1. In other words, at least a part of each of the plurality of inner pins 4 is arranged inside the outer ring 62 of the bearing member 6 .
  • the end portion on the output side of the rotation axis Ax1 in the inner pin 4 is at the same position as the bearing member 6 in the direction parallel to the rotation axis Ax1.
  • the end portion on the output side of the rotation shaft Ax1 of the inner pin 4 is inserted into the holding hole 611 formed in the inner ring 61 of the bearing member 6 , at least the end portion is arranged in the axial direction of the bearing member 6 with the bearing member 6 . same location.
  • each of the plurality of inner pins 4 is arranged at the same position as the bearing member 6 in the axial direction of the bearing member 6, whereby the size of the gear device 1 in the direction parallel to the rotation axis Ax1 can be kept small. That is, in the gear device 1 of the present basic structure, the number of gears in the direction parallel to the rotation axis Ax1 can be reduced as compared with the structure in which the bearing member 6 and the inner pin 4 are juxtaposed (opposed) in the axial direction of the bearing member 6 . The size of the device 1 can contribute to further miniaturization (thinning) of the gear device 1 .
  • the opening surface on the output side of the rotation shaft Ax1 in the holding hole 611 is closed by, for example, an output shaft or the like integrated with the inner ring 61 . Accordingly, the movement of the inner pin 4 to the output side (the right side in FIG. 9 ) of the rotation shaft Ax1 is restricted by the output shaft or the like integrated with the inner ring 61 .
  • the following structure is employ
  • the lubricant holding space 17 into which the lubricant is injected exists between the inner ring 61 and the outer ring 62 , the smooth rotation of the inner pin 4 is achieved by the lubricant in the lubricant holding space 17 .
  • the inner ring 61 has: a plurality of holding holes 611 into which the plurality of inner pins 4 are respectively inserted; and a plurality of connecting passages 64 .
  • the plurality of connecting passages 64 connect the lubricant holding space 17 between the inner ring 61 and the outer ring 62 and the plurality of holding holes 611 .
  • the inner ring 61 is formed with a connecting passage 64 extending in the radial direction from a portion of the inner peripheral surface of the holding hole 611 , that is, a portion corresponding to the rolling elements 63 .
  • connection passage 64 is a hole penetrating between the bottom surface of the concave portion (groove) in which the rolling element 63 is accommodated in the opposing surface of the inner ring 61 and the outer ring 62 and the inner peripheral surface of the holding hole 611 .
  • the opening surface of the coupling passage 64 on the lubricant holding space 17 side is arranged at a position facing (opposing) the rolling elements 63 of the bearing member 6 .
  • the lubricant holding space 17 and the holding hole 611 are spatially connected via such a connection path 64 .
  • the lubricant in the lubricant holding space 17 is supplied to the holding hole 611 through the connecting passage 64 . That is, when the bearing member 6 operates to roll the rolling elements 63 , the rolling elements 63 function as a pump and can send the lubricant in the lubricant holding space 17 to the holding holes 611 via the connecting passage 64 .
  • the opening surface of the coupling passage 64 on the lubricant holding space 17 side faces (opposes) the rolling elements 63 of the bearing member 6, whereby the rolling elements 63 effectively function as pumps when the rolling elements 63 rotate.
  • the lubricant is interposed between the inner peripheral surface of the holding hole 611 and the inner pin 4 , and the rotation of the inner pin 4 with respect to the inner ring 61 can be smoothed.
  • FIG. 10 is a cross-sectional view taken along line B1-B1 in FIG. 3 .
  • the hatching of members other than the support body 8 is omitted even in cross-section.
  • FIG. 10 only the internal gear 2 and the support body 8 are shown, and illustration of other members (inner pin 4 etc.) is abbreviate
  • illustration of the inner peripheral surface 221 of the gear body 22 is omitted.
  • the support body 8 is a member that supports the plurality of inner pins 4 . That is, the support body 8 bundles the plurality of inner pins 4 to disperse the load acting on the plurality of inner pins 4 when the rotation (rotation component) of the planetary gear 3 is transmitted to the inner ring 61 .
  • the plurality of support holes 82 into which the plurality of inner pins 4 are respectively inserted are provided.
  • the diameter of the support hole 82 is equal to the diameter of the holding hole 611 formed in the inner ring 61 . Therefore, the support body 8 supports the plurality of inner pins 4 in a state in which each of the plurality of inner pins 4 can rotate. That is, each of the plurality of inner pins 4 is held in a state capable of rotating with respect to both the inner ring 61 of the bearing member 6 and the support body 8 .
  • the positioning of the plurality of inner pins 4 with respect to the support body 8 is performed in both the circumferential direction and the radial direction of the support body 8 . That is, when the inner pin 4 is inserted into the support hole 82 of the support body 8 , movement in all directions in the plane orthogonal to the rotation axis Ax1 is restricted. Therefore, the inner pin 4 is positioned not only in the circumferential direction but also in the radial direction (radial direction) by the support body 8 .
  • the support body 8 has at least an annular shape whose outer peripheral surface 81 is a perfect circle in plan view.
  • the position of the support body 8 is regulated by bringing the outer peripheral surface 81 into contact with the plurality of pins 23 in the internally toothed gear 2 . Since the plurality of pins 23 constitute the internal teeth 21 of the internally toothed gear 2 , in other words, the position of the support body 8 is restricted by bringing the outer peripheral surface 81 into contact with the internal teeth 21 .
  • the diameter of the outer peripheral surface 81 of the support body 8 is the same as the diameter of a virtual circle (addition circle) passing through the tips of the internal teeth 21 of the internally toothed gear 2 .
  • all of the plurality of pins 23 are in contact with the outer peripheral surface 81 of the support body 8 .
  • the center of the support body 8 is positionally regulated so as to overlap with the center (rotation axis Ax1) of the internally toothed gear 2 in a state where the support body 8 is positionally regulated by the plurality of pins 23 .
  • the centering of the support body 8 is performed, and as a result, the centering of the plurality of inner pins 4 supported by the support body 8 is also performed by the plurality of pins 23 .
  • the plurality of inner pins 4 rotate (revolve) about the rotation axis Ax1 , thereby transmitting the rotation (rotation component) of the planetary gear 3 to the inner ring 61 . Therefore, the support body 8 supporting the plurality of inner pins 4 rotates about the rotation axis Ax1 together with the plurality of inner pins 4 and the inner ring 61 . At this time, since the support body 8 is centered by the plurality of pins 23, the support body 8 rotates smoothly in a state where the center of the support body 8 is maintained on the rotation axis Ax1.
  • the support body 8 rotates in the state in which the outer peripheral surface 81 of the several pins 23 contacts, the several pins 23 rotate (autorotate) with the rotation of the support body 8, respectively.
  • the support body 8 constitutes a needle bearing (needle roller bearing) together with the internally toothed gear 2, and rotates smoothly.
  • the outer peripheral surface 81 of the support body 8 rotates relative to the gear body 22 together with the plurality of inner pins 4 in a state in which the outer peripheral surface 81 of the support body 8 is in contact with the plurality of pins 23 . Therefore, if the gear body 22 of the internally toothed gear 2 is regarded as an "outer ring” and the support body 8 is regarded as an “inner ring”, the plurality of pins 23 interposed between the two are regarded as “rolling elements (rollers)" " to function. In this way, the support body 8 constitutes a needle bearing together with the internally toothed gear 2 (the gear main body 22 and the plurality of pins 23 ), and can rotate smoothly.
  • the support body 8 sandwiches the plurality of pins 23 between the gear bodies 22 , the support body 8 also functions as a “stopper” that suppresses movement of the pins 23 in the direction in which the pins 23 are separated from the inner peripheral surface 221 of the gear body 22 . That is, the plurality of pins 23 are sandwiched between the outer peripheral surface 81 of the support body 8 and the inner peripheral surface 221 of the gear main body 22 , thereby suppressing the plurality of pins 23 from floating from the inner peripheral surface 221 of the gear main body 22 . In short, in this basic structure, each of the plurality of pins 23 is in contact with the outer peripheral surface 81 of the support body 8 to restrict movement in the direction of separation from the gear main body 22 .
  • the support body 8 is located on the opposite side of the bearing member 6 from the inner ring 61 with the planetary gear 3 interposed therebetween. That is, the support body 8, the planetary gear 3, and the inner ring 61 are arranged side by side in a direction parallel to the rotation axis Ax1.
  • the support body 8 is positioned on the input side of the rotation shaft Ax1 when viewed from the planetary gear 3, and the inner ring 61 is positioned on the output side of the rotary shaft Ax1 when viewed from the planetary gear 3.
  • the support body 8 supports both ends of the inner pin 4 in the longitudinal direction (direction parallel to the rotation axis Ax1 ) together with the inner ring 61 , and the longitudinal center of the inner pin 4 is inserted through the inner pin hole 32 of the planetary gear 3 .
  • the gear device 1 of the present basic structure includes the bearing member 6 having the outer ring 62 and the inner ring 61 arranged inside the outer ring 62 , and the inner ring 61 is supported so as to be rotatable relative to the outer ring 62 .
  • the gear body 22 is fixed to the outer ring 62 .
  • the planetary gear 3 is located between the support body 8 and the inner ring 61 in the axial direction of the support body 8 .
  • the support body 8 and the inner ring 61 support the both ends of the longitudinal direction of the inner pin 4, the inclination of the inner pin 4 is difficult to generate
  • the bending force (bending moment load) acting on the plurality of inner pins 4 with respect to the rotation axis Ax1 is also easily received.
  • the support body 8 is sandwiched between the planetary gear 3 and the case 10 in the direction parallel to the rotation axis Ax1.
  • the movement of the support body 8 to the input side (left side in FIG. 9 ) of the rotation axis Ax1 is restricted by the casing 10 .
  • the movement to the input side (left side in FIG. 9 ) of the rotation shaft Ax1 is also restricted by the housing 10 about the inner pin 4 that penetrates the support hole 82 of the support body 8 and protrudes from the support body 8 to the input side of the rotation axis Ax1 .
  • the support body 8 and the inner ring 61 are also in contact with both ends of the plurality of pins 23 . That is, as shown in FIG. 9 , the support body 8 is in contact with one end (the end on the input side of the rotation axis Ax1 ) of the pin 23 in the longitudinal direction (direction parallel to the rotation axis Ax1 ). The inner ring 61 is in contact with the other end portion (the end portion on the output side of the rotational axis Ax1 ) of the pin 23 in the longitudinal direction (direction parallel to the rotational axis Ax1 ).
  • the support body 8 and the inner ring 61 are centered at both ends in the longitudinal direction of the pin 23 , the inclination of the inner pin 4 is less likely to occur.
  • the bending force (bending moment load) acting on the plurality of inner pins 4 with respect to the rotation axis Ax1 is also easily received.
  • the plurality of pins 23 have a length greater than or equal to the thickness of the support body 8 .
  • the support body 8 is received within the range of the tooth direction of the internal teeth 21 in the direction parallel to the rotation axis Ax1.
  • the outer peripheral surface 81 of the support body 8 comes into contact with the plurality of pins 23 over the entire length of the tooth direction (direction parallel to the rotation axis Ax1 ) of the inner teeth 21 . Therefore, it is difficult to cause a problem such as "one-sided wear" in which the outer peripheral surface 81 of the support body 8 is partially worn.
  • the outer peripheral surface 81 of the support body 8 is smaller in surface roughness than the one surface of the support body 8 adjacent to the outer peripheral surface 81 . That is, the surface roughness of the outer peripheral surface 81 is smaller than that of both end surfaces of the support body 8 in the axial direction (thickness direction).
  • the "surface roughness” mentioned in the embodiments of the present disclosure refers to the roughness of the surface of the object, and the smaller the value, the smaller (less) the unevenness of the surface is and the smoother it is.
  • the surface roughness is referred to as the arithmetic equilibrium roughness (Ra).
  • the surface roughness of the outer peripheral surface 81 is smaller than that of the surface other than the outer peripheral surface 81 of the support body 8 by processing such as grinding. In this structure, the rotation of the support body 8 becomes smoother.
  • the hardness of the outer peripheral surface 81 of the support body 8 is lower than the peripheral surface of the plurality of pins 23 and higher than the inner peripheral surface 221 of the gear body 22 .
  • the "hardness” mentioned in the embodiments of the present disclosure refers to the hardness of an object, and the hardness of a metal is represented by, for example, the size of an indentation formed by pressing a steel ball with a certain pressure.
  • the hardness of a metal there are Rockwell hardness (HRC), Brinell hardness (HB), Vickers hardness (HV), Shore hardness (Hs), and the like.
  • the hardness of the outer peripheral surface 81 of the support body 8 is increased by processing such as carburizing and quenching.
  • processing such as carburizing and quenching.
  • abrasion powder etc. are hard to generate
  • the gear device 1 and the actuator 100 of this basic structure are suitable for a robot such as a horizontal articulated robot, that is, a so-called Selective Compliance Assembly Robot Arm (SCARA: Selective Compliance Assembly Robot Arm) type robot, for example.
  • SCARA Selective Compliance Assembly Robot Arm
  • the application example of the gear apparatus 1 and the actuator 100 of this basic structure is not limited to the above-mentioned articulated robot,
  • industrial robots other than the articulated robot or a non-industrial robot may be used.
  • industrial robots other than the horizontal articulated robot include a vertical articulated robot, a parallel link robot, and the like.
  • robots other than industrial use include home robots, nursing robots, and medical robots.
  • the internal meshing planetary gear unit 1A (hereinafter, also simply referred to as “gear unit 1A”) of the present embodiment is mainly different from the gear unit 1 having the basic structure in the structure around the inner pin 4 .
  • symbol is attached
  • FIG. 11 is a schematic cross-sectional view of the gear unit 1A.
  • FIG. 12A is a schematic enlarged view of a region Z1 in FIG. 11
  • FIG. 12B is a cross-sectional view taken along line A1 - A1 in FIG. 12A .
  • FIG. 13 is an explanatory diagram schematically showing a force acting in the state of FIG. 12A .
  • FIG. 14 is a side view of the gear device 1A viewed from the output side (right side in FIG. 11 ) of the rotation shaft Ax1
  • FIG. 11 corresponds to a cross-sectional view taken along line A1 - A1 in FIG. 14 .
  • FIG. 15 is a side view of the gear device 1A as viewed from the input side (the left side of FIG. 11 ) of the rotation shaft Ax1 .
  • the gear device 1A of the present embodiment is configured so that a preload is applied from the planetary gears 3 to each of the inner pins 4 when the plurality of inner pins 4 are not rotating with respect to the inner gear 2 . That is, in the gear device 1A, when the plurality of inner pins 4 are non-rotating with respect to the internally toothed gear 2 , the inner peripheral surfaces 321 of the plurality of inner pin holes 32 are pressed against each of the plurality of inner pins 4 , thereby A preload (forces F1 and F2 ) acts on each of the plurality of inner pins 4 .
  • the gear device 1A further includes a support structure 40 that supports each of the plurality of inner pins 4 so as to maintain a state in which the preload is applied.
  • the support structure 40 supports the respective inner pins of the plurality of inner pins 4 so as to cancel the moment M1 (refer to FIG. 13 ) generated by the respective inner pins of the plurality of inner pins 4 due to the preload.
  • the structure (support structure 40 ) supporting the plurality of inner pins 4 is a structure in which both ends of the inner pins 4 are held by the rolling bearings 41 and 42 .
  • the gear device 1A includes a plurality of sets of rolling bearings 41, 42 that hold the respective inner pins of the plurality of inner pins 4 at both sides of the planetary gear 3 in the direction parallel to the rotation axis Ax1.
  • Each of the plurality of inner pins 4 is held by the respective sets of rolling bearings 41 and 42 in a state capable of rotating.
  • the gear device 1A of the present embodiment newly adopts the structure around the inner pin 4 , in particular, the study of the preload for the inner pin 4 and the support structure 40 (rolling bearings 41 , 42 for the inner pin 4 ) )Research.
  • the rolling bearings 41 and 42 are fixed to the inner ring 61 of the bearing member 6A, and the inner pin 4 is held by the inner ring 61 of the bearing member 6A via the rolling bearings 41 and 42 . Therefore, also in the gear device 1A of the present embodiment, it is the same as the basic structure that each of the plurality of inner pins 4 is held by the inner ring 61 in a state capable of rotating.
  • gear device 1A of the present embodiment in addition to the above-mentioned main difference (structure around the inner pin 4 ), as described below, there are many differences in the basic structure.
  • the bearing member 6A of the gear device 1A of the present embodiment includes a first bearing member 601A and a second bearing member 602A.
  • the first bearing member 601A and the second bearing member 602A are each formed of a deep groove ball bearing, and have an inner ring 61 , an outer ring 62 , and a plurality of rolling elements 63 .
  • the first bearing member 601A and the second bearing member 602A are arranged on both sides in the direction parallel to the rotation axis Ax1 with respect to the planetary gear 3 .
  • the inner ring 61 of the first bearing member 601A and the inner ring 61 of the second bearing member 602A each have an annular shape whose outer peripheral surface is a perfect circle centered on the rotation axis Ax1 in plan view.
  • the first bearing member 601A is disposed on the input side (left side in FIG. 11 ) of the rotating shaft Ax1 as viewed from the planetary gear 3 , and is disposed on the output side ( 11) the second bearing member 602A is arranged.
  • the bearing member 6A is constituted by the first bearing member 601A and the second bearing member 602A such that the radial load, the thrust direction (the direction along the rotation axis Ax1 ), and the bending force (bending moment load) to the rotation axis Ax1 are all included. Tolerable.
  • the gear device 1A of the present embodiment includes a bracket flange 18 and an output flange 19 .
  • the bracket flange 18 and the output flange 19 are fixed to the inner ring 61 of the bearing member 6A (each of the first bearing member 601A and the second bearing member 602A).
  • the carrier flange 18 and the output flange 19 are arranged on both sides of the planetary gear 3 in a direction parallel to the rotation axis Ax1, and are coupled to each other through the carrier hole 34 (see FIG. 16 ) of the planetary gear 3 .
  • the carrier flange 18 is disposed on the input side (left side in FIG.
  • the bracket flange 18 is fixed by being fitted into the inner ring 61 of the first bearing member 601A, and the output flange 19 is fixed by being fitted into the inner ring 61 of the second bearing member 602A.
  • the output flange 19 has a plurality of (six as an example) bracket pins 191 (see FIG. 16 ) protruding from one surface of the output flange 19 toward the input side of the rotation axis Ax1 .
  • the plurality of bracket pins 191 respectively penetrate through the plurality of bracket holes 34 (e.g., six) formed in the planetary gear 3 , and the tips of the plurality of bracket pins 191 are fixed to the bracket flange 18 by bracket bolts 181 (see FIG. 15 ).
  • the diameter of the bracket pin 191 is slightly smaller than the diameter of the bracket hole 34, and a gap is ensured between the bracket pin 191 and the inner peripheral surface of the bracket hole 34 so that the bracket pin 191 can move in the bracket hole 34, that is, Relatively movable with respect to the center of the bracket hole 34 . Furthermore, the gap between the bracket pin 191 and the inner peripheral surface of the bracket hole 34 is larger than the gap between the inner pin 4 and the inner peripheral surface 321 of the inner pin hole 32. When the inner pin 4 revolves in the inner pin hole 32, the bracket pin 191 does not interact with the bracket hole 34. contact with the inner surface.
  • a plurality of flange bolt holes 192 for fixing the output flange 19 itself are formed on the surface of the output flange 19 on the opposite side to the bracket pin 191 .
  • both ends of the inner pin 4 are not directly held by the inner ring 61 of the bearing member 6A, but are held by the bracket flange 18 and the output flange 19 (via the rolling bearings 41 and 42 ) integrated with the inner ring 61 . That is, the plurality of inner pins 4 are indirectly held by the inner ring 61 of the bearing member 6A because they are held by the bracket flange 18 and the output flange 19 .
  • the gear device 1A is used by taking out the rotation corresponding to the rotation component of the planetary gear 3 as the rotation of the carrier flange 18 and the output flange 19 integrated with the inner ring 61 of the bearing member 6A. That is, in the basic structure, the relative rotation between the planetary gears 3 and the internally toothed gears 2 is extracted as the rotation component of the planetary gears 3 from the inner ring 61 coupled to the planetary gears 3 by the inner pins 4 . In contrast, in the present embodiment, the relative rotation between the planetary gear 3 and the internally toothed gear 2 is extracted from the carrier flange 18 and the output flange 19 integrated with the inner ring 61 .
  • the gear device 1A is used in a state in which the outer ring 62 of the bearing member 6A is fixed to a housing serving as a fixing member. That is, the planetary gear 3 is connected to the carrier flange 18 and the output flange 19 as rotating members by the plurality of inner pins 4 , and the gear body 22 is fixed to the stationary member, so the relative rotation between the planetary gear 3 and the inner gear 2 is prevented from The rotating members (the bracket flange 18 and the output flange 19) are taken out.
  • the plurality of inner pins 4 rotate relative to the gear body 22 , the rotational force of the holder flange 18 and the output flange 19 is taken out as an output.
  • the housing 10 is seamlessly integrated with the gear body 22 of the internally toothed gear 2 . That is, in the basic structure, the gear main body 22 of the internally toothed gear 2 is used in a state of being fixed to the housing 10 together with the outer ring 62 of the bearing member 6 .
  • the gear main body 22 serving as the fixing member is provided continuously and seamlessly with the housing 10 in the direction parallel to the rotation axis Ax1.
  • the casing 10 is cylindrical, and constitutes the outer contour of the gear device 1A.
  • the central axis of the cylindrical casing 10 is configured to coincide with the rotation axis Ax1. That is, at least the outer peripheral surface of the casing 10 is a perfect circle centered on the rotation axis Ax1 in a plan view (viewed from one of the rotation axis Ax1 directions).
  • the casing 10 is formed in a cylindrical shape opened at both end surfaces in the direction of the rotation axis Ax1.
  • the housing 10 and the gear main body 22 of the internally toothed gear 2 are seamlessly integrated, so that the housing 10 and the gear main body 22 are handled as one component.
  • the inner peripheral surface of the housing 10 includes the inner peripheral surface 221 of the gear body 22 . Furthermore, the outer ring 62 of the bearing member 6A is fixed to the housing 10 . That is, the outer ring 62 of the first bearing member 601A is fixed to the input side (left side in FIG. 11 ) of the rotation shaft Ax1 by fitting, as viewed from the gear body 22 in the inner peripheral surface of the housing 10 . On the other hand, the outer ring 62 of the second bearing member 602A is fixed to the output side of the rotating shaft Ax1 (right side in FIG. 11 ) by fitting, as viewed from the gear body 22 on the inner peripheral surface of the housing 10 .
  • the oil seal 161 fills the gap between the bracket flange 18 and the housing 10
  • the oil seal 162 fills the gap between the output flange 19 and the housing 10
  • the space sealed by the plurality of oil seals 14 , 15 , 161 , and 162 constitutes the lubricant holding space 17 (see FIG. 11 ) similarly to the basic structure.
  • a plurality of installation holes 111 for fixing the case 10 itself are formed in both end surfaces in the direction parallel to the rotation axis Ax1 in the case 10 .
  • the gear device 1A of the present embodiment includes a plurality of planetary gears 3 .
  • the gear device 1A includes two planetary gears 3 , a first planetary gear 301 and a second planetary gear 302 .
  • the two planetary gears 3 are arranged to face each other in a direction parallel to the rotation axis Ax1 (with the support ring 8A interposed therebetween). That is, the planetary gears 3 include the first planetary gears 301 and the second planetary gears 302 which are juxtaposed in the direction parallel to the rotation axis Ax1.
  • These two planetary gears 3 are arranged around the rotation axis Ax1 with a phase difference of 180 degrees.
  • the center C1 of the first planetary gear 301 located on the input side (left side in FIG. 11 ) of the rotation axis Ax1 is positioned relative to the rotation axis Ax1 A state in which it deviates (offsets) toward the upper side of the drawing.
  • the center C2 of the second planetary gear 302 on the output side (right side in FIG.
  • the eccentric shaft 7 has two eccentric parts 72 for one axial part 71 .
  • the centers (central axes) of the two eccentric portions 72 coincide with the centers C1 and C2 deviated from the rotation axis Ax1 , respectively.
  • the shapes of the first planetary gears 301 and the second planetary gears 302 themselves are the same.
  • the eccentric body bearing 5 in a state of being mounted on the eccentric portion 72 centered on the center C1 is accommodated in the opening portion 33 of the first planetary gear 301 .
  • the eccentric body bearing 5 in a state of being mounted on the eccentric portion 72 centered on the center C2 is accommodated in the opening portion 33 of the second planetary gear 302 .
  • the distance ⁇ L1 between the rotation axis Ax1 and the center C1 is the eccentricity of the first planetary gear 301 relative to the rotation axis Ax1
  • the distance ⁇ L2 between the rotation axis Ax1 and the center C2 is the second planetary gear 302 relative to the rotation axis Eccentricity of Ax1.
  • FIGS. 16 and 17 show the states of the first planetary gear 301 and the second planetary gear 302 at a certain time.
  • FIG. 16 is a cross-sectional view taken along line A1-A1 of FIG. 11 , showing the first planetary gear 301 .
  • FIG. 17 is a cross-sectional view taken along the line B1-B1 of FIG. 11 , showing the second planetary gear 302 .
  • illustration of the retainer 54 is omitted, and hatching is omitted even in cross-section.
  • their centers C1 and C2 are rotationally symmetrical at 180 degrees with respect to the rotation axis Ax1 .
  • the eccentricity amount ⁇ L1 and the eccentricity amount ⁇ L2 are opposite to each other in the directions viewed from the rotation axis Ax1, but their absolute values are the same.
  • the shaft center portion 71 rotates (rotates) around the rotation axis Ax1, whereby the first planetary gear 301 and the second planetary gear 302 surround the rotation axis Ax1 with a phase difference of 180 degrees around the rotation axis Ax1. Rotation (eccentric movement).
  • the eccentric body bearing 5 is constituted by a roller bearing instead of the deep groove ball bearing as described in the basic structure. That is, in the gear device 1A of the present embodiment, the eccentric body bearing 5 uses cylindrical (cylindrical) rollers as the rolling elements 53 . Furthermore, in the present embodiment, the eccentric inner ring 51 (see FIG. 3 ) and the eccentric outer ring 52 (see FIG. 3 ) are omitted.
  • the inner peripheral surface of the planetary gear 3 (the opening portion 33 ) becomes the rolling surface of the plurality of rolling elements 53 instead of the eccentric outer ring 52
  • the outer peripheral surface of the eccentric portion 72 becomes the rolling surface of the plurality of rolling elements 53 instead of the eccentric inner ring 51 .
  • the eccentric body bearing 5 has a retainer 54, and each of the plurality of rolling elements 53 is held by the retainer 54 in a state capable of rotating itself.
  • the retainer 54 holds the plurality of rolling elements 53 at equal intervals in the circumferential direction of the eccentric portion 72 .
  • the retainer 54 is not fixed with respect to the planetary gear 3 and the eccentric shaft 7 , but is rotatable relative to the planetary gear 3 and the eccentric shaft 7 , respectively. Accordingly, the plurality of rolling elements 53 held by the retainer 54 move in the circumferential direction of the eccentric portion 72 in accordance with the rotation of the retainer 54 .
  • the gear device 1A of the present embodiment includes a support ring 8A instead of the support body 8 .
  • the support ring 8A is arranged between the two planetary gears 3 , the first planetary gear 301 and the second planetary gear 302 .
  • the support ring 8A has an annular shape whose outer peripheral surface is a perfect circle in plan view at least.
  • the position of the support ring 8A is regulated by bringing the outer peripheral surface into contact with the plurality of pins 23 of the internally toothed gear 2 .
  • the position of the support ring 8A is regulated by bringing the outer peripheral surface into contact with the internal teeth 21 .
  • the diameter of the outer peripheral surface of the support ring 8A is the same as the diameter of a virtual circle (addition circle) passing through the tips of the internal teeth 21 of the internally toothed gear 2 . Therefore, all of the plurality of pins 23 are in contact with the outer peripheral surface of the support ring 8A.
  • the center of the support ring 8A is positionally regulated so as to overlap with the center (rotation axis Ax1 ) of the internally toothed gear 2 in a state where the support ring 8A is positionally regulated by the plurality of pins 23 .
  • the support ring 8A is sandwiched between the first planetary gear 301 and the second planetary gear 302 , and rotates around the rotation axis Ax1 with the rotation (rotation) of the planetary gear 3 .
  • the support ring 8A rotates in a state in which the outer peripheral surface of the support ring 8A is in contact with the plurality of pins 23, the plurality of pins 23 rotate (autorotate) in accordance with the rotation of the support ring 8A.
  • the support ring 8A constitutes a needle bearing (needle roller bearing) together with the internally toothed gear 2, and rotates smoothly.
  • the support ring 8A constitutes a needle bearing together with the internally toothed gear 2 (the gear main body 22 and the plurality of pins 23 ), and can rotate smoothly. Furthermore, since the support ring 8A sandwiches the plurality of pins 23 with the gear body 22 , the support ring 8A also functions as a “stopper” that suppresses movement of the pins 23 in the direction in which the pins 23 are separated from the inner peripheral surface 221 of the gear body 22 . Function.
  • the gear device 1A of the present embodiment includes a spacer 55 .
  • the spacer 55 is arranged between the first bearing 91 and the second bearing 92 which are inner bearing members, and the eccentric body bearing 5 .
  • the spacers 55 are respectively arranged between the first bearing 91 and the eccentric body bearing 5 on the first planetary gear 301 side, and between the second bearing 92 and the eccentric body bearing 5 on the second planetary gear 302 side.
  • the spacer 55 has at least an annular shape whose inner peripheral surface is a perfect circle in plan view.
  • the spacer 55 functions as a "presser" of the eccentric body bearing 5, and restricts the movement of the eccentric body bearing 5 (particularly, the retainer 54) in a direction parallel to the rotation axis Ax1.
  • the spacer 55 secures a gap with respect to the first bearing 91 and the second bearing 92 and the outer rings thereof. Therefore, in the first bearing 91 and the second bearing 92 , their outer rings are not in contact with the spacer 55 , but only their inner rings are in contact with the spacer 55 .
  • the first bearing member 601A and the second bearing member 602A which are the bearing members 6A, have a gap with respect to the planetary gear 3 and the outer ring 62 thereof. Therefore, in the first bearing member 601A and the second bearing member 602A, their outer rings 62 are not in contact with the planetary gears 3 , but only their inner rings 61 are in contact with the planetary gears 3 .
  • the planetary gear 3 is in contact with the inner rings 61 of the first bearing member 601A and the second bearing member 602A, whereby the movement of the planetary gear 3 in the direction parallel to the rotation axis Ax1 is restricted, thereby suppressing the planetary gear 3 tilt.
  • the present embodiment and the The basic structure is also appropriately different.
  • 18 of the inner pin holes 32 and the inner pins 4 are each provided in the basic structure, but in the present embodiment, 6 are provided each as an example.
  • the support structure 40 supports the inner pins 4 so as to cancel the moment generated by the inner pins 4 due to the preload.
  • preload refers to a state in which internal stress is always applied by applying a preload, which is a so-called preload. That is, in the gear unit 1A of the present embodiment, when the plurality of inner pins 4 are not rotating with respect to the inner gear 2 , that is, when the gear unit 1A is not driven, the planetary gears 3 act on the inner pins 4 . pre-pressure.
  • the inner pin 4 is always in contact with the planetary gear 3 at a part of the inner peripheral surface 321 of the inner pin hole 32 , and the state where the inner pin 4 is separated from the planetary gear 3 is unlikely to occur. Therefore, when the gear device 1A is driven, the inner pin 4 revolves in the inner pin hole 32 while being pressed against the inner peripheral surface 321 of the inner pin hole 32 .
  • the gear unit 1A of the present embodiment dares to be configured as Eliminate this gap.
  • the gear device 1A of the present embodiment it is possible to reduce or eliminate at least the backlash generated by the gap between the inner peripheral surface 321 of the inner pin hole 32 and the inner pin 4 , thereby easily suppressing the angle transmission error to a small value .
  • the gear device 1A with a high reduction ratio even if there is a backlash caused by a slight backlash, the error of the rotation of the output side (output flange 19 ) with respect to the rotation of the input side (eccentric shaft 7 ) is not enough. That is to say, the angle transmission error also increases, so the effect of reducing or eliminating the backlash is large.
  • the angle transmission error at the time of starting the gear unit 1A from the stopped state to the start of rotation can be reduced, so that the starting characteristics of the gear unit 1A can be greatly improved, and the gear unit 1A can be greatly improved. responsiveness at startup or when the direction of rotation is switched. As a result, as in the field of robots, for example, even in fields where stopping, starting, or switching of the rotation direction is frequently performed and the requirements for angular transmission errors are severe, the gear device 1A can exhibit sufficient characteristics.
  • each of the plurality of inner pins 4 is held by the inner ring 61 in a state capable of autorotating.
  • each inner pin 4 is not directly held by the inner ring 61 , but is held by the bracket flange 18 and the output flange 19 (via the rolling bearings 41 and 42 ) integrated with the inner ring 61 , and thus is held by the bearing member
  • the inner ring 61 of 6A is held indirectly.
  • the inner pin 4 is kept rotatable, even if the inner pin 4 revolves in the inner pin hole 32 in a state of being pressed against the inner peripheral surface 321 of the inner pin hole 32 , the inner pin 4 is in the state of being able to rotate, so the inner pin 4 is in the rotatable state.
  • the inner peripheral surface 321 of the inner pin hole 32 rolls. In other words, since the inner pin 4 revolves in the inner pin hole 32 so as to roll on the inner peripheral surface 321 of the inner pin hole 32 , loss due to frictional resistance between the inner peripheral surface 321 of the inner pin hole 32 and the inner pin 4 is less likely to occur .
  • the support structure 40 includes a plurality of sets of holding portions 410 , which hold the respective inner pins of the plurality of inner pins 4 on both sides in the direction parallel to the rotation axis Ax1 with respect to the planetary gear 3 , 420.
  • the support structure 40 for supporting each inner pin 4 includes a plurality of sets of holding parts 410 and 420 so as to eliminate the moment generated by each inner pin 4 due to the preload.
  • the respective group holding portions 410 and 420 hold the respective inner pins 4 on both sides in the direction parallel to the rotation axis Ax1 with respect to the planetary gear 3 .
  • the holding parts 410 and 420 are provided in the same number of sets as the number of the inner pins 4 . In the present embodiment, as an example, six sets of the holding parts 410 and 420 are provided corresponding to the six inner pins 4 .
  • each set of holding parts 410 and 420 holds both ends of the inner pin 4 in the longitudinal direction.
  • the holding part 410 is arranged on the input side (left side in FIG. 12A ) of the rotation shaft Ax1 as viewed from the planetary gear 3
  • the holding part 420 is arranged on the output side (right side in FIG. 12A ) of the rotation shaft Ax1 as seen from the planetary gear 3 .
  • each of the plurality of sets of holding portions 410 and 420 includes a pair of rolling bearings 41 and 42 .
  • the holding portion 410 is formed of the rolling bearing 41
  • the holding portion 410 is formed of the rolling bearing 41 . That is, the pair of rolling bearings 41 and 42 constitute the respective group holding portions 410 and 420 . Therefore, in the present embodiment, as an example, six sets of the pair of rolling bearings 41 and 42 are provided in the same number as the holding parts 410 and 420 .
  • the rolling bearing 41 is fixed by being press-fitted to the bracket flange 18
  • the rolling bearing 42 is fixed by being press-fitted to the output flange 19 .
  • each of the rolling bearings 41 and 42 holds both ends of the inner pin 4 in the longitudinal direction in a state in which the inner pin 4 can rotate.
  • each of the rolling bearings 41 and 42 has an outer ring 401 and a plurality of rolling elements 402 .
  • the outer ring 401 is an annular member.
  • the outer ring 401 has an annular shape that is a perfect circle in plan view.
  • the inner diameter of the outer ring 401 is larger than the diameter (outer diameter) of the inner pin 4 by one turn, a gap is generated between the inner peripheral surface of the outer ring 401 and the outer peripheral surface of the inner pin 4 .
  • the plurality of rolling elements 402 are arranged in the gap between the outer ring 401 and the inner pin 4 .
  • the plurality of rolling elements 402 are arranged in parallel along the circumferential direction of the outer ring 401 .
  • the plurality of rolling elements 402 are all metal members of the same shape, and are provided at equal intervals over the entire area of the outer ring 401 in the circumferential direction.
  • each of the rolling bearings 41 and 42 is a needle bearing (needle roller bearing) as an example. That is, each of the rolling bearings 41 and 42 has cylindrical rollers as the rolling elements 402 . In addition, the axes of the cylindrical rolling elements 402 are all arranged parallel to the rotation axis Ax1. In the present embodiment, each of the rolling bearings 41 and 42 does not have an inner ring, and the inner pin 4 functions as an inner ring. Therefore, by rolling the plurality of rolling elements 402 in the rolling bearings 41 and 42 , the inner pin 4 rotates relative to the outer ring 401 , and the rolling bearings 41 and 42 can hold the inner pin 4 rotatably.
  • needle roller bearing needle roller bearing
  • the gear device 1A of the present embodiment includes the plurality of sets of rolling bearings 41 , 42 holding each of the plurality of inner pins 4 at both sides in the direction parallel to the rotation axis Ax1 with respect to the planetary gear 3 .
  • Each of the plurality of inner pins 4 is held by the set of rolling bearings 41 and 42 in a rotatable state. According to this configuration, the inner pin 4 can rotate, and the loss due to frictional resistance between the inner peripheral surface 321 of the inner pin hole 32 and the inner pin 4 is unlikely to occur, so the inner roller can be omitted.
  • the inner pin 4 in which the inner roller is not attached is inserted into the inner pin hole 32 so that the inner pin 4 directly contacts the inner peripheral surface 321 of the inner pin hole 32 .
  • the inner roller can be omitted and the diameter of the inner pin hole 32 can be kept relatively small, so that the planetary gear 3 can be reduced in size (especially, the diameter), and the entire gear device 1A can be easily reduced in size.
  • the holding portions 410 and 420 that hold the inner pins 4 include a pair of rolling bearings 41 and 42 . Therefore, when the inner pin 4 rotates, a loss due to frictional resistance between the inner pin 4 and the holding parts 410 and 420 is less likely to occur.
  • the inner pin 4 connects the planetary gear 3 to the rotating member (the carrier flange 18 and the output flange 19 ), and at least when the gear unit 1A is driven, a bending force (bending moment load) acts on the inner pin 4 . Therefore, for example, when the inner pin 4 is held by the sliding bearing, the frictional resistance between the inner pin 4 and the holding parts 410 and 420 increases due to the bending force, and the loss due to the frictional resistance increases.
  • the holding parts 410 and 420 include the rolling bearings 41 and 42 .
  • the respective inner peripheral surfaces 321 of the plurality of inner pin holes 32 are directed toward the plurality of inner pins 4 .
  • the respective inner pins are pressed against each other, whereby a preload (forces F1 and F2 ) is applied to each of the plurality of inner pins 4 from the planetary gear 3 .
  • a preload forces F1 and F2
  • the bending force bending moment load
  • the holding parts 410 and 420 include the rolling bearings 41 and 42 , even if a large bending force acts on the inner pin 4 , the frictional resistance between the inner pin 4 and the holding parts 410 and 420 is hardly affected. It is also particularly useful for the structure of
  • the surface of the inner pin 4 and the surface of the rolling elements 402 of the rolling bearings 41 and 42 are pressed against each other elastically by the reaction forces F3 and F4.
  • the inner pin 4 and the rolling elements 402 are elastically deformed by the Hertz contact stress (stress or pressure applied to the elastic contact portion) acting between the inner pin 4 and the surfaces of the rolling elements 402 .
  • the deformation amount due to the elastic deformation of the inner pin 4 as a beam is larger than the deformation amount due to the Hertzian contact stress. Therefore, even if elastic deformation due to the Hertzian contact stress occurs, at least the elastic deformation of the inner pin 4 itself causes a force (reaction force) to act on the planetary gears 3 (the first planetary gear 301 and the second planetary gear 302 ) from the inner pin 4 . ) can also be maintained above a constant value. In other words, the inner pin 4 maintains a pressing state with respect to the inner peripheral surface 321 of the inner pin hole 32 of the first planetary gear 301 and the inner peripheral surface 321 of the inner pin hole 32 of the second planetary gear 302 . As a result, the "preload" acting on the inner pin 4 from the planetary gear 3 is maintained.
  • the preload acts by the bending moment generated in each of the plurality of inner pins 4 . That is, in the present embodiment, the "preload" is maintained by taking advantage of the fact that the deformation amount due to the elastic deformation of the inner pin 4 due to the bending moment acting on the inner pin 4 is larger than the deformation amount due to the Hertzian contact stress. In other words, by using the elasticity of the inner pin 4 itself, the inner peripheral surface 321 of the inner pin hole 32 is pressed against the inner pin 4 , whereby the preload is applied from the planetary gear 3 to the inner pin 4 . Therefore, the number of parts can be kept small without providing other parts for generating the preload except the inner pin 4, which contributes to the miniaturization of the gear device 1A as a result.
  • the above-mentioned preload is realized by the negative clearance (negative clearance) provided between the inner pin 4 and the inner peripheral surface 321 of the inner pin hole 32 .
  • the "negative clearance” mentioned in the embodiments of the present disclosure refers to the so-called “interference amount”, and if the two are assembled according to the design between them, the two are referred to as mutually overlapping (pressing).
  • the inner pin 4 is theoretically located at a distance from the inner pin hole 32 when viewed in the direction of the rotation axis Ax1
  • the state in which the inner peripheral surface 321 is pressed against the inner pin 4 .
  • a negative gap that is provided between each of the plurality of inner pins 4 and each of the inner peripheral surfaces 321 of the plurality of inner pin holes 32 and is equal to or less than 1/100 of the diameter of each of the inner pins 4 acts. pre-pressure.
  • the magnitude of the negative clearance for realizing the preload is set to be equal to or greater than 0 and equal to or less than 1/100 of the diameter of each of the inner pins 4 .
  • the negative gap between the inner pin 4 and the inner peripheral surface 321 of the inner pin hole 32 is preferably 0 mm or more and 0.05 mm or less.
  • the magnitude of the negative gap between the inner pin 4 and the inner peripheral surface 321 of the inner pin hole 32 is preferably 1/200 of the diameter of the inner pin 4, and more preferably 1/300 or less.
  • negative clearances are uniformly set for a plurality of (here, six) inner pins 4 . Therefore, when the plurality of inner pins 4 are non-rotating with respect to the inner gear 2 , a preload is applied from the planetary gears 3 by pressing the inner peripheral surfaces 321 of the plurality of inner pin holes 32 against all of the plurality of inner pins 4 .
  • this structure is not necessarily required for the gear device 1A, and the preload may not be applied to a part of the plurality of inner pins 4 .
  • the preload is applied to the inner pin 4 not only from the planetary gear 3 but also from the rolling bearings 41 and 42 . That is, about the pair of rolling bearings 41 and 42 holding the inner pin 4 , a negative gap is also set between the plurality of rolling elements 402 and the inner pin 4 .
  • the difference between the inner diameter of the outer ring 401 and the diameter (diameter) of the inner pin 4 is equal to or less than twice the diameter (diameter) of the rolling elements 402 . Thereby, a negative clearance (interference) of 0 or more is generated between the inner pin 4 and the rolling elements 402 .
  • the fitting tolerance of the inner pin 4 with respect to the rolling bearings 41 and 42 is preferably "k6" or more, and more preferably "p6".
  • the plurality of sets of rolling bearings 41 and 42 each have a plurality of rolling elements 402 . By pressing the plurality of rolling elements 402 , an inner pin-side preload is applied to each of the plurality of inner pins 4 .
  • the clearance between the inner pin 4 and the rolling bearings 41 and 42 serving as the holding parts 410 and 420 is reduced or eliminated, and the backlash of the inner pin 4 caused by the clearance can be suppressed.
  • the gear device 1A of the present embodiment it is possible to reduce or eliminate the backlash generated by the gap between the inner pin 4 and the rolling bearings 41 and 42 , thereby easily suppressing the angle transmission error to a small value.
  • negative clearances are uniformly set for the rolling bearings 41 and 42 for a plurality of (here, six) inner pins 4 . Therefore, the inner pin side preload acts on all of the plurality of inner pins 4 from both the rolling bearings 41 and 42 .
  • this structure is not necessarily required for the gear device 1A, and the inner pin side preload may not be applied to a part of the plurality of inner pins 4 .
  • the arrangement of the plurality of sets of rolling bearings 41 and 42 in the direction parallel to the rotation axis Ax1 is at a position overlapping at least a part of the first bearing 91 and the second bearing 92 . That is, in the direction parallel to the rotation axis Ax1, at least a part of the rolling bearing 41 is at the same position as the first bearing 91, and at least a part of the rolling bearing 42 is at the same position as the second bearing 92.
  • the dimension in the width direction (direction parallel to the rotation axis Ax1 ) of the first bearing 91 and the second bearing 92 is smaller than the dimension in the width direction of the rolling bearings 41 and 42 .
  • each bearing of the first bearing 91 and the second bearing 92 is accommodated within the respective ranges of the rolling bearings 41 and 42 in the direction parallel to the rotation axis Ax1.
  • each bearing of the first bearing 91 and the second bearing 92 is arranged inside each of the rolling bearings 41 and 42 .
  • the gear device 1A of the present embodiment includes the inner bearing members (the first bearing 91 and the second bearing 92 ) that hold the eccentric shaft 7 that eccentrically oscillates the planetary gear 3 rotatably with respect to the inner ring 61 .
  • the gear device 1A of the present embodiment includes the inner bearing members (the first bearing 91 and the second bearing 92 ) that hold the eccentric shaft 7 that eccentrically oscillates the planetary gear 3 rotatably with respect to the inner ring 61 .
  • the gear device 1A of the present embodiment includes the inner bearing members (the first bearing 91 and the second bearing 92 ) that hold the eccentric shaft 7 that eccentrically oscillates the planetary gear 3 rotatably with respect to the inner ring 61 .
  • the first bearing 91 and the second bearing 92 constitute the eccentric shaft 7 that eccentrically oscillates the planetary gear 3 via the carrier flange 18 and the output flange 19 so as to be able to hold the eccentric shaft 7 relative to the inner ring 61 of the (bearing member 6A) Rotating "inboard bearing member".
  • the space originally provided outside the inner bearing member (the first bearing 91 and the second bearing 92 ) of the gear device 1A is used as the installation space for the rolling bearings 41 and 42 . Therefore, it is possible to suppress an increase in the size of the gear device 1A in the direction parallel to the rotation axis Ax1 due to the provision of the rolling bearings 41 and 42 .
  • the first bearing member 601A and the second bearing member 602A are at least partially overlapping. That is, in the direction parallel to the rotation axis Ax1, at least a part of the rolling bearing 41 is at the same position as the first bearing member 601A, and at least a part of the rolling bearing 42 is at the same position as the second bearing member 602A.
  • the dimension in the width direction (direction parallel to the rotation axis Ax1 ) of the first bearing member 601A and the second bearing member 602A is substantially the same as the dimension in the width direction of the rolling bearings 41 and 42 . Therefore, the respective bearing members of the first bearing member 601A and the second bearing member 602A are accommodated in the respective ranges of the rolling bearings 41 and 42 in the direction parallel to the rotation axis Ax1. In other words, the respective bearing members of the first bearing member 601A and the second bearing member 602A are provided on the outer sides of the rolling bearings 41 and 42 .
  • the gear device 1A of the present embodiment at least a part of the plurality of sets of rolling bearings 41 and 42 is located at the same position as the bearing member 6A (the first bearing member 601A and the second bearing member 602A) in the direction parallel to the rotation axis Ax1.
  • the space originally provided inside the bearing member 6A (the first bearing member 601A and the second bearing member 602A) of the gear device 1A is used as the installation space for the rolling bearings 41 and 42 . Therefore, it is possible to suppress an increase in the size of the gear device 1A in the direction parallel to the rotation axis Ax1 due to the provision of the rolling bearings 41 and 42 .
  • the rolling bearings 41 and 42 are arranged outside the inner bearing members (the first bearing 91 and the second bearing 92) and inside the bearing member 6A (the first bearing member 601A and the second bearing member 602A).
  • the rolling bearings 41 and 42 are arranged using the space between the inner bearing members (the first bearing 91 and the second bearing 92 ) and the bearing member 6A (the first bearing member 601A and the second bearing member 602A). Therefore, it is possible to suppress an increase in the size of the gear device 1A in the radial direction (direction orthogonal to the rotation axis Ax1 ) due to the provision of the rolling bearings 41 and 42 .
  • the arrangement of the plurality of sets of rolling bearings 41 and 42 viewed from the direction parallel to the rotation axis Ax1 is basically the same as the arrangement of the plurality of inner pins 4 . That is, as shown in FIGS. 16 and 17 , when an imaginary circle VC1 passing through the center of each of the plurality of inner pins 4 is set when viewed from a direction parallel to the rotation axis Ax1 , the plurality of sets of rolling bearings 41 and 42 are arranged on the imaginary circle. on VC1.
  • the present embodiment particularly as shown in FIG.
  • the plurality of sets of rolling bearings 41 and 42 are arranged at equal intervals in the circumferential direction around the rotation axis Ax1 when viewed from a direction parallel to the rotation axis Ax1 .
  • the arrangement of the rolling bearing 41 is shown, and the arrangement of the rolling bearing 42 is also the same.
  • hatching is abbreviate
  • the plurality of sets of rolling bearings 41 and 42 are arranged on the virtual circle VC1 at equal intervals in the circumferential direction of the virtual circle VC1. That is to say, viewed from a direction parallel to the rotation axis Ax1, the virtual circle VC1 passes through the respective centers of the plurality of rolling bearings 41 (or 42), and the virtual circle VC1 between two adjacent rolling bearings 41 (or 42) is on the virtual circle VC1 The distance is uniform for the plurality of rolling bearings 41 (or 42 ). According to this arrangement, the plurality of inner pins 4 are held by the plurality of sets of rolling bearings 41 and 42 , and the force applied to the plurality of inner pins 4 can be equally distributed when the gear device 1A is driven.
  • the center of a virtual circle VC1 passing through the centers of the plurality of sets of rolling bearings 41 and 42 coincides with the rotation axis Ax1 when viewed from a direction parallel to the rotation axis Ax1 .
  • the center of the virtual circle VC1 is equal to the center of the gear body 22 of the internal gear 2, the center of the pitch circle of the internal teeth 21, and the like, and is located on the rotation axis Ax1.
  • the gear device 1A of the present embodiment constitutes a joint device 200 for a robot together with the first member 201 and the second member 202 .
  • the joint device 200 for a robot of the present embodiment includes the gear device 1A, the first member 201 and the second member 202 .
  • the first member 201 is fixed by the outer ring 62 .
  • the second member 202 is fixed by the inner ring 61 .
  • FIG. 19 is a schematic diagram of the robot joint device 200 corresponding to the cross-sectional view taken along the line B1-B1 in FIG. 13 .
  • the first member 201 and the second member 202 are schematically shown.
  • the first member 201 is indirectly fixed to the outer ring 62 of the bearing member 6A by being fixed to the plurality of installation holes 111 formed in the housing 10 .
  • the second member 202 is indirectly fixed to the inner ring 61 of the bearing member 6A by being fixed to the plurality of flange bolt holes 192 formed in the output flange 19 .
  • the thus-configured joint device 200 for a robot functions as a joint device by relatively rotating the first member 201 and the second member 202 around the rotation axis Ax1.
  • the first member 201 and the second member 202 relatively rotate.
  • the rotation (input rotation) generated by the drive source 101 is decelerated at a relatively high reduction ratio in the gear device 1A, and the first member 201 or the second member 202 is driven with a relatively high torque. That is to say, the first member 201 and the second member 202 connected by the gear device 1A are capable of bending and extending around the rotation axis Ax1.
  • the joint device 200 for a robot is used for a robot such as a horizontal articulated robot (articulated robot), for example.
  • the robot joint device 200 is not limited to the articulated robot, and can be used for industrial robots other than the articulated robot, robots other than industrial robots, and the like, for example.
  • the gear device 1A of the present embodiment is not limited to the joint device 200 for a robot, but can be used for vehicles such as an automated guided vehicle (AGV) as a wheel device such as an in-wheel motor.
  • AGV automated guided vehicle
  • the first embodiment is only one of various implementations of the embodiments of the present disclosure.
  • Embodiment 1 Various changes can be made in accordance with designs and the like as long as the objects of the embodiments of the present disclosure can be achieved.
  • the drawings referred to in the embodiments of the present disclosure are all schematic diagrams, and the respective ratios of the sizes and thicknesses of the structural elements in the drawings are not necessarily limited to reflect the actual size ratios.
  • modifications of the first embodiment will be listed. The modified examples described below can be applied in combination as appropriate.
  • the planetary gear 3 is exemplified as two types of the gear device 1A, but the gear device 1A may include three or more planetary gears 3 .
  • the gear device 1A may include only one planetary gear 3 .
  • two of the three planetary gears 3 may be in the same phase, and the remaining one planetary gear 3 may be rotated 180 degrees around the rotation axis Ax1 phase difference configuration.
  • the three planetary gears 3 themselves function as "support members" for supporting each of the plurality of inner pins 4 so as to cancel the moment M1 (refer to FIG. 13 ) generated in each of the plurality of inner pins 4 by the preload.
  • the inner pin 4 is not necessarily held by the holding parts 410 and 420 (rolling bearings 41 and 42 ) at both ends, but may be held by the holding parts 410 and 420 (rolling bearings 41 and 42 ) only at one end.
  • the plurality of sets of rolling bearings 41 and 42 may not be located at the same positions as the inner bearing members (the first bearing 91 and the second bearing 92 ) in the direction parallel to the rotation axis Ax1 .
  • the plurality of sets of rolling bearings 41 and 42 may be arranged in parallel with the inner bearing member (the first bearing 91 and the second bearing 92 ) in the direction parallel to the rotation axis Ax1 .
  • the plurality of sets of rolling bearings 41 and 42 may not be at the same position as the bearing member 6A (the first bearing member 601A and the second bearing member 602A) in the direction parallel to the rotation axis Ax1.
  • the plurality of sets of rolling bearings 41 and 42 may be arranged in parallel with the bearing member 6A (the first bearing member 601A and the second bearing member 602A) in the direction parallel to the rotation axis Ax1.
  • the plurality of sets of rolling bearings 41 and 42 may not be arranged at equal intervals in the circumferential direction around the rotation axis Ax1 when viewed from a direction parallel to the rotation axis Ax1. Furthermore, when viewed from a direction parallel to the rotation axis Ax1, the center of the virtual circle VC1 passing through the centers of the plurality of sets of rolling bearings 41 and 42 does not need to coincide with the rotation axis Ax1.
  • the number of inner pins 4 and the number of pins 23 (the number of teeth of the inner teeth 21 ), the number of teeth of the outer teeth 31 and the like described in the first embodiment are merely examples, and may be appropriately changed.
  • the bearing member 6A may be a crossed roller bearing, an angular contact ball bearing, or the like, as in the basic structure.
  • the bearing member 6A such as a four-point contact ball bearing, can withstand radial loads, loads in the thrust direction (directions along the rotation axis Ax1), and bending forces (bending moment loads) with respect to the rotation axis Ax1. by.
  • eccentric body bearing 5 is not limited to the roller ball bearing, and may be, for example, a deep groove ball bearing, an angular contact ball bearing, or the like.
  • each constituent element of the gear device 1A is not limited to metal, for example, resin such as engineering plastic may be used.
  • the gear device 1A is not limited to the inner ring 61 (the bracket flange 18 and the output flange 19 ) as long as the relative rotation between the inner ring 61 and the outer ring 62 of the bearing member 6 can be taken out as an output.
  • the rotational force is taken out of the structure as an output.
  • the rotational force of the outer ring 62 (case 10 ) that rotates relative to the inner ring 61 may be taken out as the output.
  • the lubricant is not limited to a liquid substance such as lubricating oil (oil), and may be a gel substance such as grease.
  • the gear device 1A may include inner rollers. That is, in the gear device 1A, each of the plurality of inner pins 4 does not necessarily have to be in direct contact with the inner peripheral surface 321 of the inner pin hole 32 , and inner rollers may be interposed between each of the plurality of inner pins 4 and the inner pin hole 32 . In such a case, the inner roller is fitted to the inner pin 4 so as to be able to rotate on the inner pin 4 as an axis.
  • each of the plurality of inner pins 4 may be held by the inner ring 61 in a rotatable state, and it is not essential for the gear device 1A that each of the plurality of inner pins 4 is held by the rolling bearings 41 and 42 .
  • each of the plurality of inner pins 4 may be directly held by the inner ring 61, or may be directly held by the bracket flange 18 integrated with the inner ring 61, the output flange 19, or the like.
  • the support ring 8A is not necessary for the gear device 1A, and the support ring 8A may be appropriately omitted, or the support body 8 described in the basic structure may be used instead of the support ring 8A.
  • the gear device 1A only needs to employ at least one of the study on the preload of the inner pin 4 and the study on the support structure 40 of the inner pin 4 , and it is not necessary to use both of them. That is, in the gear device 1A, only the case in which the preload is applied by pressing the inner peripheral surface 321 of the inner pin hole 32 against the inner pin 4 (a study of the preload on the inner pin 4 ), and the one equipped with the rolling bearings 41 and 42 holding the inner pin 4 can be adopted. Any of the cases (research on the support structure 40 of the inner pin 4) may be sufficient.
  • the gear device 1A only needs to employ at least one of the study of the preload for the inner pin 4 and the study of the support structure 40 of the inner pin 4 , and other structures can be appropriately omitted or changed according to the basic structure.
  • the inner pin 4 may be held in a press-fitted state with respect to the inner ring 61 (or the bracket flange 18 or the output flange 19 integrated with the inner ring 61 ).
  • each of the plurality of inner pins 4 is held in a state of being unable to rotate with respect to the inner ring 61 .
  • each of the plurality of inner pins 4 may be arranged at the same position as the bearing member 6A in the axial direction of the bearing member 6A.
  • the internal meshing planetary gear device (1, 1A) of the first form includes a bearing member (6, 6A), an internally toothed gear (2), a planetary gear (3), a plurality of inner pins (4), and a plurality of Set of rolling bearings (41, 42).
  • the bearing member (6, 6A) has an outer ring (62) and an inner ring (61) arranged inside the outer ring (62), and supports the inner ring (61) so as to be rotatable relative to the outer ring (62) by a rotation axis ( Ax1) is the center of relative rotation.
  • the internal gear (2) has internal teeth (21) and is fixed to the outer ring (62).
  • the planetary gear (3) has external teeth (31) partially meshed with the internal teeth (21).
  • the plurality of inner pins (4) are respectively inserted into the plurality of inner pin holes (32) formed in the planetary gear (3), and rotate relative to the inner gear (2) while revolving in the inner pin holes (32).
  • a plurality of sets of rolling bearings (41, 42) hold respective inner pins of the plurality of inner pins (4) at both sides in a direction parallel to the rotation axis (Ax1) with respect to the planetary gear (3).
  • Each of the plurality of inner pins (4) is held by each set of rolling bearings (41, 42) in a state of being able to rotate.
  • the inner pin (4) can rotate, and the loss due to frictional resistance between the inner peripheral surface (321) of the inner pin hole (32) and the inner pin (4) is less likely to occur, so the inner roller can be omitted. Therefore, since the inner roller can be omitted and the diameter of the inner pin hole (32) can be kept relatively small, the planetary gear (3) can be reduced in size, and the entire internal meshing planetary gear device (1, 1A) can also be reduced in size. It is easy to realize miniaturization.
  • the inner pin (4) is held by the rolling bearings (41, 42) on both sides of the planetary gear (3) in the direction parallel to the rotation axis (Ax1), so that the inner pin (4) is not easily caused when it rotates. loss due to frictional resistance.
  • the internal meshing planetary gear device (1, 1A) of the second aspect further includes inner bearing members (first bearing 91, second bearing 92) in addition to the first aspect.
  • the inner bearing members (first bearing 91, second bearing 92) hold the eccentric shaft (7) eccentrically swinging the planetary gear (3) rotatably with respect to the inner ring (61).
  • At least a part of the plurality of sets of rolling bearings (41, 42) is at the same position as the inner bearing member (first bearing 91, second bearing 92) in a direction parallel to the rotation axis (Ax1).
  • an increase in the size of the ring planetary gear device (1, 1A) in the direction parallel to the rotation axis (Ax1) due to the provision of the rolling bearings (41, 42) can be suppressed.
  • an increase in the size of the ring planetary gear device (1, 1A) in the direction parallel to the rotation axis (Ax1) due to the provision of the rolling bearings (41, 42) can be suppressed.
  • At least the backlash generated by the gap between the inner peripheral surface (321) of the inner pin hole (32) and the inner pin (4) can be reduced or eliminated, and the angle transmission error can be kept small. Furthermore, even if the preload is applied to the inner pin (4), loss due to frictional resistance is less likely to occur when the inner pin (4) rotates.
  • a preload is applied by the bending moment generated in each of the plurality of inner pins (4).
  • the number of parts can be kept small without providing other parts for generating the preload except for the inner pin (4), and as a result, it is possible to contribute to the miniaturization of the internal meshing planetary gear device (1, 1A). change.
  • each of the plurality of sets of rolling bearings (41, 42) has a plurality of rolling elements (402).
  • the plurality of rolling elements (402) press against the respective inner pins of the plurality of inner pins (4), so that an inner pin side pre-pressure acts on each inner pin of the plurality of inner pins (4).
  • the backlash generated by the clearance between the inner pin (4) and the rolling bearings (41, 42) can be reduced or eliminated, and the angle transmission error can be kept small.
  • a plurality of sets of rolling bearings (41, 42) They are arranged at equal intervals in the circumferential direction around the rotation axis (Ax1).
  • the plurality of inner pins (4) are held by the plurality of sets of rolling bearings (41, 42), and the force applied to the plurality of inner pins (4) can be equally distributed when the inner meshing planetary gear device (1, 1A) is driven. dispersion.
  • the plurality of sets of rolling bearings (41, The center of the virtual circle (VC1) at the center of 42) coincides with the rotation axis (Ax1).
  • the ninth aspect of the robot joint device (200) includes: the internal meshing planetary gear device (1, 1A) of any one of the first to eighth aspects; a first member (201) fixed by an outer ring (62); The inner ring (61) is fixed to the second member (202).
  • the diameter of the inner pin hole (32) can be kept relatively small, so that the planetary gear (3) can be reduced in size, and the robot joint device (200) as a whole can be easily reduced in size.
  • the structures of the second to eighth aspects are not necessarily provided for the internal meshing planetary gear device (1, 1A), and can be appropriately omitted.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Robotics (AREA)
  • Retarders (AREA)
  • Support Of The Bearing (AREA)
  • Rolling Contact Bearings (AREA)

Abstract

本公开实施例提供容易小型化的内啮合行星齿轮装置及机器人用关节装置。内啮合行星齿轮装置(1A)包括轴承构件(6A)、内齿齿轮(2)、行星齿轮(3)、多个内销(4)和多组滚动轴承(41、42)。多个内销(4)在分别插入到在行星齿轮(3)形成的多个内销孔(32)中的状态下，一边在内销孔(32)内公转一边相对于内齿齿轮(2)相对旋转。多组滚动轴承(41、42)相对于行星齿轮(3)在与旋转轴Ax1平行的方向的两侧处保持多个内销(4)的各个内销。多个内销(4)的各个内销以能够自转的状态而保持于各组滚动轴承(41、42)。

Description

内啮合行星齿轮装置和机器人用关节装置
相关申请的交叉引用
本申请基于申请号为特愿2021-030510、申请日为2021年2月26日的日本专利申请提出，并要求该日本专利申请的优先权，该日本专利申请的全部内容在此引入本申请作为参考。
技术领域
本公开实施例一般性地涉及内啮合行星齿轮装置和机器人用关节装置，更详细而言，涉及在具有内齿的内齿齿轮的内侧配置有具有外齿的行星齿轮的内啮合行星齿轮装置和机器人用关节装置。
背景技术
作为关联技术，已知有行星齿轮一边进行偏心摆动一边与内齿齿轮进行内啮合的、所谓的偏心摆动类型的齿轮装置(例如，参照专利文献1)。在关联技术的齿轮装置中，偏心体与输入轴一体形成，且在偏心体经由偏心体轴承来安装行星齿轮。在行星齿轮的外周形成有圆弧齿形等的外齿。
内齿齿轮通过将一个个地构成内齿的多个销(滚子销)旋转自如地装入于兼作为壳体的齿轮主体(内齿齿轮主体)的内周面而构成。在行星齿轮，沿圆周方向以适当的间隔形成有多个内销孔(内滚子孔)，在内销孔插入有内销及内滚子。内销在其轴向的一端侧与支架连结，支架经由交叉滚子轴承而旋转自如地支承于壳体。该齿轮装置能够作为将内齿齿轮固定时的行星齿轮的相当于自转分量的旋转从支架取出的齿轮装置来使用。
现有技术文献
专利文献
专利文献1：日本特开2003-74646号公报
发明内容
发明所要解决的技术问题
在上述关联技术的结构中，由于用于减少因行星齿轮的内销孔的内周面与内销之间的摩擦阻力而引起的损失的内滚子是必需的，因此难以实现内销孔的小型化，例如妨碍行星齿轮的小型化等。
本公开实施例的目的在于提供容易小型化的内啮合行星齿轮装置及机器人用关节装置。
用于解决技术问题的方案
本公开实施例的一形态的内啮合行星齿轮装置包括轴承构件、内齿齿轮、行星齿轮、多个内销和多组滚动轴承。所述轴承构件具有外圈及配置于所述外圈的内侧的内圈，将所述内圈支承为能够相对于所述外圈以旋转轴为中心相对旋转。所述内齿齿轮具有内齿且固定于所述外圈。所述行星齿轮具有与所述内齿局部性地啮合的外齿。所述多个内销在分别插入到形成在所述行星齿轮的多个内销孔的状态下，一边在所述内销孔内公转一边相对于所述内齿齿轮相对旋转。所述多组滚动轴承相对于所述行星齿轮在与所述旋转轴平行的方向的两侧处保持所述多个内销的各个内销。所述多个内销的各个内销以能够自转的状态而保持于各组滚动轴承。
本公开实施例的一形态的机器人用关节装置包括所述内啮合行星齿轮装置、固定于所述外圈的第一构件和固定于所述内圈的第二构件。
发明效果
根据本公开实施例，能够提供容易小型化的内啮合行星齿轮装置及机器人用关节装置。
附图说明
图1是示出包含基本结构的内啮合行星齿轮装置在内的执行器的概略结构的立体图。
图2是上述的内啮合行星齿轮装置的从旋转轴的输出侧观察到的概略的分解立体图。
图3是上述的内啮合行星齿轮装置的概略剖视图。
图4是示出上述的内啮合行星齿轮装置的、图3的A1-A1线剖视图。
图5A是以单体示出上述的内啮合行星齿轮装置的行星齿轮的立体图。
图5B是以单体示出上述的内啮合行星齿轮装置的行星齿轮的主视图。
图6A是以单体示出上述的内啮合行星齿轮装置的轴承构件的立体图。
图6B是以单体示出上述的内啮合行星齿轮装置的轴承构件的主视图。
图7A是以单体示出上述的内啮合行星齿轮装置的偏心轴的立体图。
图7B是以单体示出上述的内啮合行星齿轮装置的偏心轴的主视图。
图8A是以单体示出上述的内啮合行星齿轮装置的支承体的立体图。
图8B是以单体示出上述的内啮合行星齿轮装置的支承体的主视图。
图9是示出上述的内啮合行星齿轮装置的、图3的区域Z1的放大图。
图10是示出上述的内啮合行星齿轮装置的、图3的B1-B1线剖视图。
图11是实施方式一的内啮合行星齿轮装置的概略剖视图。
图12A是示出上述的内啮合行星齿轮装置的、图11的区域Z1的概略放大图。
图12B是示出上述的内啮合行星齿轮装置的、图12A的A1-A1线剖视图。
图13示出上述的内啮合行星齿轮装置，是示意性地表示在图12A的状态下作用的力的说明图。
图14是上述的内啮合行星齿轮装置的从旋转轴的输出侧观察到的侧视 图。
图15是上述的内啮合行星齿轮装置的从旋转轴的输入侧观察到的侧视图。
图16是示出上述的内啮合行星齿轮装置的、图11的A1-A1线剖视图。
图17是示出上述的内啮合行星齿轮装置的、图11的B1-B1线剖视图。
图18是示出上述的内啮合行星齿轮装置中的、滚动轴承的配置的说明图。
图19是示出使用了上述的内啮合行星齿轮装置的机器人用关节装置的概略剖视图。
具体实施方式
(基本结构)
(1)概要
以下，参照图1～图3进行关于本基本结构的内啮合行星齿轮装置1的概要。本公开实施例参照的附图都是示意性的图，图中的各结构要素的大小及厚度各自的比未必反映实际的尺寸比。例如，图1～图3中的内齿21及外齿31的齿形、尺寸及齿数等都不过是为了说明而示意性地表示的，其主旨并不限定为图示的形状。
本基本结构的内啮合行星齿轮装置1(以下，也简称为“齿轮装置1”)是包括内齿齿轮2、行星齿轮3和多个内销4的齿轮装置。在该齿轮装置1中，在环状内齿齿轮2的内侧配置有行星齿轮3，而且，在行星齿轮3的内侧配置有偏心体轴承5。偏心体轴承5具有偏心体内圈51及偏心体外圈52，偏心体内圈51绕着从偏心体内圈51的中心C1(参照图3)偏离的旋转轴Ax1(参照图3)进行旋转(偏心运动)，由此使行星齿轮3摆动。偏心体内圈51例如通过插入于偏心体内圈51的偏心轴7的旋转而绕着旋转轴Ax1进行旋转(偏心运动)。另外，内啮合行星齿轮装置1还包括轴承构件6， 轴承构件6具有外圈62及内圈61。内圈61配置于外圈62的内侧，并被支承为能够相对于外圈62相对旋转。
内齿齿轮2具有内齿21且固定于外圈62。特别是在本基本结构中，内齿齿轮2具有环状的齿轮主体22和多个销23。多个销23以能够自转的状态保持于齿轮主体22的内周面221而构成内齿21。行星齿轮3具有与内齿21局部性地啮合的外齿31。也就是说，在内齿齿轮2的内侧，行星齿轮3内切于内齿齿轮2，成为外齿31的一部分与内齿21的一部分啮合的状态。在该状态下，当偏心轴7旋转时行星齿轮3摆动，内齿21与外齿31的啮合位置沿内齿齿轮2的圆周方向移动，在两齿轮(内齿齿轮2及行星齿轮3)之间产生与行星齿轮3和内齿齿轮2的齿数差对应的相对旋转。此处，如果将内齿齿轮2固定，则伴随着两齿轮的相对旋转而行星齿轮3旋转(自转)。其结果是，从行星齿轮3获得与两齿轮的齿数差相应地以比较高的减速比被减速了的旋转输出。
这种齿轮装置1以下述方式使用：将行星齿轮3的相当于自转分量的旋转作为例如与轴承构件6的内圈61一体化的输出轴的旋转而取出。由此，齿轮装置1以偏心轴7为输入侧，以输出轴为输出侧，作为比较高的减速比的齿轮装置发挥功能。因此，在本基本结构的齿轮装置1中，为了将行星齿轮3的相当于自转分量的旋转向轴承构件6的内圈61传递而利用多个内销4将行星齿轮3与内圈61连结。多个内销4在分别插入到形成于行星齿轮3的多个内销孔32的状态下，分别一边在内销孔32内公转一边相对于内齿齿轮2相对旋转。也就是说，内销孔32具有比内销4大的直径，内销4能够以插入于内销孔32的状态在内销孔32内公转的方式进行移动。并且，行星齿轮3的摆动分量、也就是说行星齿轮3的公转分量通过行星齿轮3的内销孔32与内销4的游嵌而被吸收。换言之，多个内销4以分别在多个内销孔32内公转的方式进行移动，由此吸收行星齿轮3的摆动分量。因此，通过多个内销4，将除了行星齿轮3的摆动分量(公转分量)之外的、 行星齿轮3的旋转(自转分量)向轴承构件6的内圈61传递。
然而，在这种齿轮装置1中，内销4在行星齿轮3的内销孔32内一边公转，一边向多个内销4传递行星齿轮3的旋转，因此作为第一关联技术，已知有使用装配于内销4而能够以内销4为轴进行旋转的内滚子的技术。也就是说，在第一关联技术中，内销4保持为以被压入于内圈61(或与内圈61一体的支架)的状态，当内销4在内销孔32内公转之际，内销4相对于内销孔32的内周面321滑动。因此，作为第一关联技术，为了减少因内销孔32的内周面321与内销4之间的摩擦阻力而引起的损失而使用内滚子。但是，如果是第一关联技术那样包括内滚子的结构，则内销孔32需要具有使带内滚子的内销4能够公转的直径，内销孔32的小型化困难。当内销孔32的小型化困难时，会妨碍行星齿轮3的小型化(特别是小径化)，甚至妨碍齿轮装置1整体的小型化。本基本结构的齿轮装置1通过以下的结构而能够提供容易小型化的内啮合行星齿轮装置1。
即，如图1～图3所示，本基本结构的齿轮装置1包括轴承构件6、内齿齿轮2、行星齿轮3和多个内销4。轴承构件6具有外圈62及配置于外圈62的内侧的内圈61。内圈61被支承为相对于外圈62能够相对旋转。内齿齿轮2具有内齿21且固定于外圈62。行星齿轮3具有与内齿21局部性地啮合的外齿31。多个内销4在分别插入到形成于行星齿轮3的多个内销孔32的状态下，一边在内销孔32内公转一边相对于内齿齿轮2相对旋转。此处，多个内销4各自以能够旋转的状态保持于内圈61。进一步，多个内销4各自将至少一部分配置于在轴承构件6的轴向上与轴承构件6相同的位置。
根据该形态，多个内销4各自以能够自转的状态由内圈61保持，因此内销4在内销孔32内公转之际，内销4自身能够自转。因此，即使不使用装配于内销4而能够以内销4为轴进行旋转的内滚子，也能够减少因内销孔32的内周面321与内销4之间的摩擦阻力而引起的损失。因此，对于本 基本结构的齿轮装置1而言，内滚子并非必须，故而有容易小型化的优点。而且，多个内销4各自将至少一部分配置于在轴承构件6的轴向上与轴承构件6相同的位置，因此能够将轴承构件6的轴向上的齿轮装置1的尺寸抑制得小。也就是说，与轴承构件6和内销4沿轴承构件6的轴向并列(相对)的结构相比，在本基本结构的齿轮装置1中，能够减小轴向上的齿轮装置1的尺寸，从而能够对齿轮装置1的进一步小型化(薄型化)作出贡献。
进一步，如果行星齿轮3的尺寸与上述第一关联技术相同，则与上述第一关联技术相比，例如，还能够增加内销4的个数(根数)从而使旋转的传递顺畅，或者使内销4变粗从而提高强度。
另外，在这种齿轮装置1中，内销4需要在行星齿轮3的内销孔32内公转，因此作为第二关联技术，存在多个内销4仅由内圈61(或与内圈61一体的支架)保持的情况。根据第二关联技术，多个内销4的定芯的精度难以提高，由于定芯不佳而可能会导致振动的产生、及传递效率的下降等不良状况。也就是说，多个内销4分别一边在内销孔32内公转一边相对于内齿齿轮2相对旋转，由此将行星齿轮3的自转分量向轴承构件6的内圈61传递。此时，如果因多个内销4的定芯的精度不够而多个内销4的旋转轴相对于内圈61的旋转轴偏离或倾斜，则成为定芯不佳的状态，可能导致振动的产生及传递效率的下降等不良状况。本基本结构的齿轮装置1通过以下的结构，能够提供难以产生因多个内销4的定芯不佳而引起的不良状况的内啮合行星齿轮装置1。
即，图1～图3所示，本基本结构的齿轮装置1包括内齿齿轮2、行星齿轮3、多个内销4和支承体8。内齿齿轮2具有环状的齿轮主体22和多个销23。多个销23以能够自转的状态保持于齿轮主体22的内周面221而构成内齿21。行星齿轮3具有与内齿21局部性地啮合的外齿31。多个内销4在分别插入到在行星齿轮3形成的多个内销孔32的状态下，一边在内 销孔32内公转一边相对于齿轮主体22相对旋转。支承体8为环状并支承多个内销4。此处，支承体8通过使外周面81与多个销23接触而被进行位置限制。
根据该形态，多个内销4由环状的支承体8支承，因此多个内销4由支承体8捆束，可抑制多个内销4的相对的偏离及倾斜。而且，支承体8的外周面81与多个销23接触，由此进行支承体8的位置限制。总之，通过多个销23进行支承体8的定芯，结果是，关于被支承体8支承的多个内销4也利用多个销23进行定芯。因此，根据本基本结构的齿轮装置1，容易实现多个内销4的定芯的精度提高，并具有难以产生因多个内销4的定芯不佳而引起的不良状况这样的优点。
另外，如图1所示，本基本结构的齿轮装置1与驱动源101一起构成执行器100。换言之，本基本结构的执行器100包括齿轮装置1和驱动源101。驱动源101产生用于使行星齿轮3摆动的驱动力。具体而言，驱动源101使偏心轴7以旋转轴Ax1为中心旋转，由此使行星齿轮3摆动。
(2)定义
本公开实施例中所说的“环状”是指至少在俯视时如在内侧形成包围而成的空间(区域)的圈(环)那样的形状，并不限于在俯视时为正圆的圆形状(圆环状)，例如也可以是椭圆形状和多边形状等。进一步，例如，即使是杯状那样具有底部的形状，只要其周壁为环状，就包含在“环状”内。
本公开实施例所说的“游嵌”是指嵌成具有游隙(间隙)的状态，内销孔32是供内销4游嵌的孔。也就是说，内销4以在与内销孔32的内周面321之间确保了空间的富余度(间隙)的状态插入于内销孔32。换言之，内销4中的、至少插入于内销孔32的部位的直径比内销孔32的直径小(细)。因此，内销4在插入于内销孔32的状态下，能够在内销孔32内移动，也就是说能够相对于内销孔32的中心相对地移动。由此，内销4能够在内销 孔32内公转。但是，在内销孔32的内周面321与内销4之间，无需确保作为空洞的间隙，例如，也可以在该间隙填充液体等流体。
本公开实施例所说的“公转”是指某物体环绕通过该物体的中心(重心)的中心轴以外的旋转轴转圈，当某物体公转时，该物体的中心沿着以旋转轴为中心的公转轨道移动。因此，例如，在某物体以与通过该物体的中心(重心)的中心轴平行的偏心轴为中心旋转的情况下，该物体以偏心轴为旋转轴公转。作为一例，内销4环绕通过内销孔32的中心的旋转轴转圈地在内销孔32内公转。
另外，在本公开实施例中，有将旋转轴Ax1的一方侧(图3的左侧)称为“输入侧”，将旋转轴Ax1的另一方侧(图3的右侧)称为“输出侧”的情况。在图3的例中，从旋转轴Ax1的“输入侧”向旋转体(偏心体内圈51)赋予旋转，从旋转轴Ax1的“输出侧”取出多个内销4(内圈61)的旋转。但是，“输入侧”及“输出侧”只不过是为了说明而赋予的标签，其主旨并不限定从齿轮装置1观察到的、输入及输出的位置关系。
在本公开实施例中所说的“旋转轴”是指成为旋转体的旋转运动的中心的虚拟性的轴(直线)。也就是说，旋转轴Ax1是不伴有实体的虚拟轴。偏心体内圈51以旋转轴Ax1为中心进行旋转运动。
在本公开实施例中所说的“内齿”和“外齿”分别指多个“齿”的集合(组)而不是单体的“齿”。也就是说，内齿齿轮2的内齿21由配置于内齿齿轮2(齿轮主体22)的内周面221的多个齿的集合构成。同样，行星齿轮3的外齿31由配置于行星齿轮3的外周面的多个齿的集合构成。
(3)结构
以下，关于本基本结构的内啮合行星齿轮装置1的详细结构，参照图1～图8B进行说明。
图1是示出包含齿轮装置1的执行器100的概略结构的立体图。在图1中，示意性地示出驱动源101。图2是齿轮装置1的从旋转轴Ax1的输出 侧观察到的概略的分解立体图。图3是齿轮装置1的概略剖视图。图4是图3的A1-A1线剖视图。其中，在图4中，关于偏心轴7以外的部件，虽然也是剖面但是省略了剖面线。进一步，在图4中，省略了齿轮主体22的内周面221的图示。图5A及图5B是以单体示出行星齿轮3的立体图及主视图。图6A及图6B是以单体示出轴承构件6的立体图及主视图。图7A及图7B是以单体示出偏心轴7的立体图及主视图。图8A及图8B是以单体示出支承体8的立体图及主视图。
(3.1)整体结构
如图1～图3所示，本基本结构的齿轮装置1包括内齿齿轮2、行星齿轮3、多个内销4、偏心体轴承5、轴承构件6、偏心轴7和支承体8。另外，在本基本结构中，齿轮装置1还包括第一轴承91、第二轴承92及壳体10。在本基本结构中，作为齿轮装置1的结构要素的内齿齿轮2、行星齿轮3、多个内销4、偏心体轴承5、轴承构件6、偏心轴7及支承体8等的材质是不锈钢、铸铁、机械结构用碳素钢、铬钼钢、磷青铜或铝青铜等金属。此处所说的金属包括实施了氮化处理等表面处理的金属。
另外，在本基本结构中，作为齿轮装置1的一例，例示使用了摆线类齿形的内切式行星齿轮减速装置。也就是说，本基本结构的齿轮装置1包括具有摆线类曲线齿形的内切式的行星齿轮3。
另外，在本基本结构中，作为一例，齿轮装置1在内齿齿轮2的齿轮主体22与轴承构件6的外圈62一起固定于壳体10等固定构件的状态下使用。由此，伴随着内齿齿轮2与行星齿轮3的相对旋转，行星齿轮3相对于固定构件(壳体10等)相对旋转。
进一步，在本基本结构中，在将齿轮装置1用于执行器100的情况下，通过向偏心轴7施加作为输入的旋转力，从而从与轴承构件6的内圈61一体化的输出轴取出作为输出的旋转力。也就是说，齿轮装置1以偏心轴7的旋转为输入旋转，以与内圈61一体化的输出轴的旋转为输出旋转进行动 作。由此，在齿轮装置1中，可得到相对于输入旋转以比较高的减速比被减速了的输出旋转。
驱动源101是马达(电动机)等动力的产生源。由驱动源101产生的动力向齿轮装置1中的偏心轴7传递。具体而言，驱动源101经由输入轴与偏心轴7相连，由驱动源101产生的动力经由输入轴向偏心轴7传递。由此，驱动源101能够使偏心轴7旋转。
进一步，在本基本结构的齿轮装置1中，如图3所示，输入侧的旋转轴Ax1与输出侧的旋转轴Ax1处于同一直线上。换言之，输入侧的旋转轴Ax1与输出侧的旋转轴Ax1为同轴。此处，输入侧的旋转轴Ax1是被赋予输入旋转的偏心轴7的旋转中心，输出侧的旋转轴Ax1是产生输出旋转的内圈61(及输出轴)的旋转中心。也就是说，在齿轮装置1中，能够在同轴上相对于输入旋转而得到以比较高的减速比被减速了的输出旋转。
如图4所示，内齿齿轮2是具有内齿21的环状的部件。在本基本结构中，内齿齿轮2具有至少内周面在俯视观察下为正圆的圆环状。在圆环状的内齿齿轮2的内周面，沿着内齿齿轮2的圆周方向形成有内齿21。构成内齿21的多个齿全部为同一形状，且以等间距地设置于内齿齿轮2的内周面的圆周方向的整个区域。也就是说，内齿21的节圆在俯视时为正圆。内齿21的节圆的中心处于旋转轴Ax1上。另外，内齿齿轮2沿旋转轴Ax1的方向具有规定的厚度。内齿21的齿向均与旋转轴Ax1平行。内齿21的齿向方向的尺寸比内齿齿轮2的厚度方向稍小。
此处，如上所述，内齿齿轮2具有环状(圆环状)的齿轮主体22和多个销23。多个销23以能够自转的状态保持于齿轮主体22的内周面221而构成内齿21。换言之，多个销23分别作为构成内齿21的多个齿发挥功能。具体而言，如图2所示，在齿轮主体22的内周面221在圆周方向的整个区域形成有多个槽。多个槽全部为同一形状，且以等间距地设置。多个槽均与旋转轴Ax1平行，并遍及齿轮主体22的厚度方向的全长地形成。多个销 23以嵌于多个槽的方式组合于齿轮主体22。多个销23各自被保持为能够在槽内自转的状态。另外，齿轮主体22(与外圈62一起)固定于壳体10。因此，在齿轮主体22形成有固定用的多个固定孔222。
如图4所示，行星齿轮3是具有外齿31的环状的部件。在本基本结构中，行星齿轮3具有至少外周面在俯视观察下成为正圆的圆环状。在圆环状的行星齿轮3的外周面，沿着行星齿轮3的圆周方向形成有外齿31。构成外齿31的多个齿全部为同一形状，且等间距地设置于行星齿轮3的外周面的圆周方向的整个区域。也就是说，外齿31的节圆在俯视观察下为正圆。外齿31的节圆的中心C1处于距旋转轴Ax1偏离了距离ΔL(参照图4)的位置。另外，行星齿轮3沿旋转轴Ax1的方向具有规定的厚度。外齿31均遍及行星齿轮3的厚度方向的全长地形成。外齿31的齿向均与旋转轴Ax1平行。在行星齿轮3中，与内齿齿轮2不同，外齿31与行星齿轮3的主体由一个金属构件一体形成。
此处，对于行星齿轮3组合有偏心体轴承5及偏心轴7。也就是说，在行星齿轮3形成有呈圆形状地开口的开口部33。开口部33是沿着厚度方向贯通行星齿轮3的孔。在俯视观察下，开口部33的中心与行星齿轮3的中心一致，开口部33的内周面(行星齿轮3的内周面)与外齿31的节圆为同心圆。在行星齿轮3的开口部33收容有偏心体轴承5。进一步，通过将偏心轴7插入于偏心体轴承5(的偏心体内圈51)，来将偏心体轴承5及偏心轴7组合于行星齿轮3。在行星齿轮3组合有偏心体轴承5及偏心轴7的状态下，当偏心轴7旋转时，行星齿轮3绕着旋转轴Ax1摆动。
这样构成的行星齿轮3配置于内齿齿轮2的内侧。在俯视观察下，行星齿轮3形成得比内齿齿轮2小一圈，行星齿轮3在与内齿齿轮2组合的状态下，能够在内齿齿轮2的内侧摆动。此时，在行星齿轮3的外周面形成有外齿31，在内齿齿轮2的内周面形成有内齿21。因此，在内齿齿轮2的内侧配置有行星齿轮3的状态下，外齿31与内齿21相互相对。
进一步，外齿31的节圆比内齿21的节圆小一圈。并且，在行星齿轮3内切于内齿齿轮2的状态下，外齿31的节圆的中心C1处于从内齿21的节圆的中心(旋转轴Ax1)偏离了距离ΔL(参照图4)的位置。因此，外齿31与内齿21的至少一部分隔着间隙相对，不存在圆周方向的整体相互啮合的情况。但是，行星齿轮3在内齿齿轮2的内侧绕着旋转轴Ax1摆动(公转)，因此外齿31与内齿21局部性地啮合。也就是说，通过行星齿轮3绕着旋转轴Ax1摆动，如图4所示，构成外齿31的多个齿中的一部分的齿与构成内齿21的多个齿中的一部分的齿啮合。结果是，在齿轮装置1中，能够使外齿31的一部分与内齿21的一部分啮合。
此处，内齿齿轮2中的内齿21的齿数比行星齿轮3的外齿31的齿数多N(N为正整数)。在本基本结构中，作为一例，N为“1”，行星齿轮3的(外齿31的)齿数比内齿齿轮2的(内齿21的)齿数多“1”。这样的行星齿轮3与内齿齿轮2的齿数差规定了齿轮装置1中的输出旋转相对于输入旋转的减速比。
另外，在本基本结构中，作为一例，行星齿轮3的厚度比内齿齿轮2中的齿轮主体22的厚度小。进一步，外齿31的齿向方向(与旋转轴Ax1平行的方向)的尺寸比内齿21的齿向方向(与旋转轴Ax1平行的方向)的尺寸小。换言之，在与旋转轴Ax1平行的方向上，外齿31收于内齿21的齿向的范围内。
在本基本结构中，如上所述，行星齿轮3的相当于自转分量的旋转作为与轴承构件6的内圈61一体化了的输出轴的旋转(输出旋转)而取出。因此，行星齿轮3利用多个内销4与内圈61连结。如图5A及图5B所示，在行星齿轮3形成有用于供多个内销4插入的多个内销孔32。内销孔32设置与内销4相同的个数，在本基本结构中，作为一例，内销孔32及内销4各设置18个。多个内销孔32各自是呈圆形状地开口并沿着厚度方向贯穿行星齿轮3的孔。多个(此处为18个)内销孔32在与开口部33同心的虚 拟圆上沿圆周方向等间隔地配置。
多个内销4是将行星齿轮3与轴承构件6的内圈61连结的部件。多个内销4各自形成为圆柱状。多个内销4的直径及长度在多个内销4中相同。内销4的直径比内销孔32的直径小一圈。由此，内销4以在与内销孔32的内周面321之间确保有空间的富余度(间隙)的状态插入于内销孔32(参照图4)。
轴承构件6是具有外圈62及内圈61并用于取出齿轮装置1的输出作为内圈61相对于外圈62的旋转的部件。轴承构件6除了外圈62及内圈61之外，还具有多个滚动体63(参照图3)。
如图6A及图6B所示，外圈62及内圈61均为环状的部件。外圈62及内圈61均具有在俯视观察下为正圆的圆环状。内圈61比外圈62小一圈并配置于外圈62的内侧。此处，外圈62的内径由于比内圈61的外径大，所以在外圈62的内周面与内圈61的外周面之间产生间隙。
内圈61具有供多个内销4分别插入的多个保持孔611。保持孔611设置与内销4相同的个数，在本基本结构中，作为一例，保持孔611设置18个。如图6A及图6B所示，多个保持孔611各自是呈圆形状地开口并沿着厚度方向贯穿内圈61的孔。多个(此处为18个)保持孔611在与内圈61的外周同心的虚拟圆上沿圆周方向等间隔地配置。保持孔611的直径为内销4的直径以上，且比内销孔32的直径小。
进一步，内圈61与输出轴一体化，且取出内圈61的旋转作为输出轴的旋转。因此，在内圈61形成有用于安装输出轴的多个输出侧安装孔612(参照图2)。在本基本结构中，多个输出侧安装孔612比多个保持孔611更靠内侧，且配置于与内圈61的外周同心的虚拟圆上。
外圈62与内齿齿轮2的齿轮主体22一起固定于壳体10等固定构件。因此，在外圈62形成有固定用的多个透孔621。具体而言，如图3所示，外圈62在与壳体10之间夹有齿轮主体22的状态下，利用穿过透孔621及 齿轮主体22的固定孔222的固定用的螺钉(螺栓)60而固定于壳体10。
多个滚动体63配置于外圈62与内圈61之间的间隙。多个滚动体63沿外圈62的圆周方向并列配置。多个滚动体63全部为同一形状的金属部件，在外圈62的圆周方向的整个区域等间距地设置。
在本基本结构中，作为一例，轴承构件6为交叉滚子轴承。也就是说，轴承构件6具有圆筒状的滚子作为滚动体63。并且，圆筒状的滚动体63的轴相对于与旋转轴Ax1正交的平面具有45度的倾斜，并且与内圈61的外周正交。进一步，在内圈61的圆周方向上相互相邻的一对滚动体63配置成轴向相互正交的朝向。在这样的由交叉滚子轴承构成的轴承构件6中，径向的载荷、推力方向(沿着旋转轴Ax1的方向)的载荷、及对于旋转轴Ax1的弯曲力(弯曲力矩载荷)均容易承受。而且，通过一个轴承构件6，能够耐受这三种载荷，从而能够确保所需的刚性。
如图7A及图7B所示，偏心轴7是圆筒状的部件。偏心轴7具有轴心部71和偏心部72。轴心部71具有至少外周面在俯视观察下为正圆的圆筒状。轴心部71的中心(中心轴)与旋转轴Ax1一致。偏心部72具有至少外周面在俯视观察下为正圆的圆盘状。偏心部72的中心(中心轴)与从旋转轴Ax1偏离的中心C1一致。此处，旋转轴Ax1与中心C1之间的距离ΔL(参照图7B)成为偏心部72相对于轴心部71的偏心量。偏心部72呈在轴心部71的长度方向(轴向)的中央部从轴心部71的外周面遍及整周地突出的凸缘形状。根据上述的结构，对于偏心轴7而言，通过轴心部71以旋转轴Ax1为中心旋转(自转)，从而使得偏心部72进行偏心运动。
在本基本结构中，轴心部71及偏心部72由一个金属构件一体形成，由此，实现无缝的偏心轴7。这样的形状的偏心轴7与偏心体轴承5一起组合于行星齿轮3。因此，当偏心轴7以在行星齿轮3组合有偏心体轴承5及偏心轴7的状态进行旋转时，行星齿轮3绕着旋转轴Ax1摆动。
进一步，偏心轴7具有沿轴向(长度方向)贯通轴心部71的贯通孔73。 贯通孔73在轴心部71中的轴向的两端面呈圆形状地开口。贯通孔73的中心(中心轴)与旋转轴Ax1一致。能够在贯通孔73穿过例如电源线及信号线等线缆类。
另外，在本基本结构中，从驱动源101向偏心轴7施加作为输入的旋转力。因此，在偏心轴7形成有用于安装与驱动源101相连的输入轴的多个输入侧安装孔74(参照图7A及图7B)。在本基本结构中，多个输入侧安装孔74在轴心部71的轴向的一端面的贯通孔73的周围，并配置在与贯通孔73同心的虚拟圆上。
偏心体轴承5是具有偏心体外圈52及偏心体内圈51、并吸收偏心轴7的旋转中的自转分量、并用于仅将除了偏心轴7的自转分量之外的偏心轴7的旋转也就是说偏心轴7的摆动分量(公转分量)向行星齿轮3传递的部件。偏心体轴承5除了偏心体外圈52及偏心体内圈51以外，还具有多个滚动体53(参照图3)。
偏心体外圈52及偏心体内圈51均为环状的部件。偏心体外圈52及偏心体内圈51均具有在俯视观察下为正圆的圆环状。偏心体内圈51比偏心体外圈52小一圈，且配置于偏心体外圈52的内侧。此处，偏心体外圈52的内径比偏心体内圈51的外径大，因此在偏心体外圈52的内周面与偏心体内圈51的外周面之间产生间隙。
多个滚动体53配置于偏心体外圈52与偏心体内圈51之间的间隙。多个滚动体53沿偏心体外圈52的圆周方向并列配置。多个滚动体53全部为同一形状的金属部件，并等间距地配置于偏心体外圈52的圆周方向的整个区域。在本基本结构中，作为一例，偏心体轴承5由使用滚珠作为滚动体53的深沟球轴承构成。
此处，偏心体内圈51的内径与偏心轴7中的偏心部72的外径一致。偏心体轴承5以在偏心体内圈51插入有偏心轴7的偏心部72的状态与偏心轴7组合。另外，偏心体外圈52的外径与行星齿轮3中的开口部33的 内径(直径)一致。偏心体轴承5以在行星齿轮3的开口部33嵌入有偏心体外圈52的状态与行星齿轮3组合。换言之，在行星齿轮3的开口部33收容有装配于偏心轴7的偏心部72的状态的偏心体轴承5。
另外，在本基本结构中，作为一例，偏心体轴承5中的偏心体内圈51的宽度方向(与旋转轴Ax1平行的方向)的尺寸与偏心轴7的偏心部72的厚度大体相同。偏心体外圈52的宽度方向(与旋转轴Ax1平行的方向)的尺寸比偏心体内圈51的宽度方向的尺寸稍小。进一步，偏心体外圈52的宽度方向的尺寸比行星齿轮3的厚度大。因此，在与旋转轴Ax1平行的方向上，在偏心体轴承5的范围内收有行星齿轮3。另一方面，偏心体外圈52的宽度方向的尺寸比内齿21的齿向方向(与旋转轴Ax1平行的方向)的尺寸小。因此，在与旋转轴Ax1平行的方向上，在内齿齿轮2的范围内收有偏心体轴承5。
在偏心体轴承5及偏心轴7组合于行星齿轮3的状态下，当偏心轴7旋转时，在偏心体轴承5中，偏心体内圈51绕着从偏心体内圈51的中心C1偏离的旋转轴Ax1旋转(偏心运动)。此时，偏心轴7的自转分量由偏心体轴承5吸收。因此，通过偏心体轴承5仅将除了偏心轴7的自转分量之外的偏心轴7的旋转、也就是说偏心轴7的摆动分量(公转分量)向行星齿轮3传递。由此，当偏心轴7以在行星齿轮3组合有偏心体轴承5及偏心轴7的状态进行旋转时，行星齿轮3绕着旋转轴Ax1摆动。
如图8A及图8B所示，支承体8是形成为环状并支承多个内销4的部件。支承体8具有供多个内销4插入的多个支承孔82。支承孔82设置与内销4相同的个数，在本基本结构中作为一例，支承孔82设置18个。如图8A及图8B所示，多个支承孔82各自是呈圆形状地开口并沿着厚度方向贯通支承体8的孔。多个(此处为18个)支承孔82在与支承体8的外周面81同心的虚拟圆上沿圆周方向等间隔地配置。支承孔82的直径为内销4的直径以上，且比内销孔32的直径小。在本基本结构中，作为一例，支承孔 82的直径与形成于内圈61的保持孔611的直径相等。
如图3所示，支承体8以从旋转轴Ax1的一方侧(输入侧)与行星齿轮3相对的方式配置。并且，通过向多个支承孔82插入多个内销4，支承体8以捆束多个内销4的方式发挥功能。进一步，支承体8通过使外周面81与多个销23接触而被进行位置限制。由此，通过多个销23来进行支承体8的定芯，结果是，关于被支承体8支承多个内销4，也利用多个销23进行定芯。关于支承体8，在“(3.3)支承体”一栏中进行详细说明。
第一轴承91及第二轴承92分别装配于偏心轴7的轴心部71。具体而言，如图3所示，第一轴承91及第二轴承92以在与旋转轴Ax1平行的方向上夹着偏心部72的方式装配于轴心部71中的偏心部72的两侧。从偏心部72观察时，第一轴承91配置于旋转轴Ax1的输入侧。从偏心部72观察时，第二轴承92配置于旋转轴Ax1的输出侧。第一轴承91将偏心轴7保持为相对于壳体10能够旋转。第二轴承92将偏心轴7保持为相对于轴承构件6的内圈61能够旋转。由此，偏心轴7的轴心部71在与旋转轴Ax1平行的方向上的偏心部72的两侧的两个部位处被保持为能够旋转。
壳体10为圆筒状，并在旋转轴Ax1的输出侧具有凸缘部11。在凸缘部11形成有用于将壳体10自身固定的多个设置孔111。另外，在壳体10中的旋转轴Ax1的输出侧的端面形成有轴承孔12。轴承孔12呈圆形状地开口。通过向轴承孔12内嵌入第一轴承91，从而将第一轴承91安装于壳体10。
另外，在壳体10的旋转轴Ax1的输出侧的端面且在轴承孔12的周围形成有多个螺纹孔13。多个螺纹孔13用于将内齿齿轮2的齿轮主体22及轴承构件6的外圈62固定于壳体10而使用。具体而言，固定用的螺钉60穿过外圈62的透孔621及齿轮主体22的固定孔222而拧紧到螺纹孔13，由此将齿轮主体22及外圈62固定于壳体10。
另外，如图3所示，本基本结构的齿轮装置1还包括多个油封14、15、 16等。油封14装配于偏心轴7的旋转轴Ax1的输入侧的端部，并填塞壳体10与偏心轴7(轴心部71)之间的间隙。油封15装配于偏心轴7的旋转轴Ax1的输出侧的端部，并填塞内圈61与偏心轴7(轴心部71)之间的间隙。油封16装配于轴承构件6的旋转轴Ax1的输出侧的端面，并填塞内圈61与外圈62之间的间隙。由这些多个油封14、15、16密闭的空间构成润滑剂保持空间17(参照图9)。润滑剂保持空间17包含轴承构件6的内圈61与外圈62之间的空间。进一步，在润滑剂保持空间17内收容有多个销23、行星齿轮3、偏心体轴承5、支承体8、第一轴承91及第二轴承92等。
并且，在润滑剂保持空间17封入有润滑剂。润滑剂为液体，能够在润滑剂保持空间17内流动。因此，在齿轮装置1的使用时，例如润滑剂进入由多个销23构成的内齿21与行星齿轮3的外齿31的啮合部位。本公开实施例所说的“液体”包括液状或凝胶状的物质。在此所说的“凝胶状”是指具有液体与固体的中间性质的状态，包括由液相和固相这两个相构成的胶质(colloid)的状态。例如，分散剂为液相且分散质为液相的乳剂(emulsion)，分散质为固相的悬浮液(suspension)等称为凝胶(gel)或溶胶(sol)的状态包含于“凝胶状”。而且，分散剂为固相且分散质为液相的状态也包含于“凝胶状”。在本实施方式中，作为一例，润滑剂为液状的润滑油(油液)。
在上述的结构的齿轮装置1中，向偏心轴7施加作为输入的旋转力，从而偏心轴7以旋转轴Ax1为中心进行旋转，由此行星齿轮3绕着旋转轴Ax1摆动(公转)。此时，行星齿轮3以在内齿齿轮2的内侧内切于内齿齿轮2且外齿31的一部分啮合于内齿21的一部分的状态摆动，因此内齿21与外齿31的啮合位置沿内齿齿轮2的圆周方向移动。由此，在两齿轮(内齿齿轮2及行星齿轮3)之间产生与行星齿轮3与内齿齿轮2的齿数差对应的相对旋转。并且，通过多个内销4，将除了行星齿轮3的摆动分量(公转 分量)之外的、行星齿轮3的旋转(自转分量)向轴承构件6的内圈61传递。其结果是，从一体化于内圈61的输出轴，可得到与两齿轮的齿数差相应地以比较高的减速比被减速了的旋转输出。
然而，如上所述，在本实施方式的齿轮装置1中，内齿齿轮2与行星齿轮3的齿数差规定了齿轮装置1中的输出旋转相对于输入旋转的减速比。也就是说，在将内齿齿轮2的齿数设为“V1”并将行星齿轮3的齿数设为“V2”的情况下，减速比R1由下述式1表示。
R1＝V2/(V1-V2)……(式1)
总之，内齿齿轮2与行星齿轮3的齿数差(V1-V2)越小，则减速比R1越大。作为一例，内齿齿轮2的齿数V1为“52”，行星齿轮3的齿数V2为“51”，其齿数差(V1-V2)为“1”，因此根据上述式1，减速比R1为“51”。在这样的情况下，从旋转轴Ax1的输入侧观察时，当偏心轴7以旋转轴Ax1为中心顺时针旋转一周(360度)，则内圈61以旋转轴Ax1为中心逆时针旋转齿数差”1”的量(也就是说约7.06度)。
根据本基本结构的齿轮装置1，这样高的减速比R1能够通过一级齿轮(内齿齿轮2及行星齿轮3)的组合来实现。
另外，齿轮装置1只要至少包括内齿齿轮2、行星齿轮3、多个内销4、轴承构件6和支承体8即可，例如，还可以包括花键衬套等作为结构要素。
然而，在如本基本结构的齿轮装置1那样成为高速旋转侧的输入旋转伴有偏心运动的情况下，如果未取得进行高速旋转的旋转体的平衡，则可能会导致振动等，因此有时使用平衡配重等来取得重量平衡。即，由偏心体内圈51及偏心体内圈51一起旋转的构件(偏心轴7)中的至少一者构成的旋转体以高速进行偏心运动，因此优选取得该旋转体的相对于旋转轴Ax1的重量平衡。在本基本结构中，如图3及图4所示，通过在偏心轴7的偏心部72的一部分设置空隙75来取得旋转体相对于旋转轴Ax1的重量平衡。
总之，在本基本结构中，不附加平衡配重等而通过减薄旋转体(此处 为偏心轴7)的一部分进行轻量化，由此取得旋转体相对于旋转轴Ax1的重量平衡。即，本基本结构的齿轮装置1包括收容于形成在行星齿轮3的开口部33并使行星齿轮3摆动的偏心体轴承5。偏心体轴承5具有偏心体外圈52及配置于偏心体外圈52的内侧的偏心体内圈51。从偏心体内圈51的旋转轴Ax1观察，由偏心体内圈51及偏心体内圈51一起旋转的构件的至少一者构成的旋转体在偏心体外圈52的中心C1侧的一部具有空隙75。在本基本结构中，偏心轴7是“与偏心体内圈51一起旋转的构件”，相当于“旋转体”。因此，在偏心轴7的偏心部72形成的空隙75相当于旋转体的空隙75。如图3及图4所示，该空隙75在从旋转轴Ax1观察下处于中心C1侧的位置，因此发挥作用以使偏心轴7的重量平衡从旋转轴Ax1至周向接近均等。
更详细而言，空隙75包含形成在沿着偏心体内圈51的旋转轴Ax1贯通旋转体的贯通孔73的内周面上的凹部。也就是说，在本基本结构中，旋转体为偏心轴7，因此在沿着旋转轴Ax1贯通偏心轴7的贯通孔73的内周面上形成的凹部作为空隙75发挥功能。如此，通过将形成于贯通孔73的内周面的凹部作为空隙75来利用，能够在不伴有外观上的变更的情况下取得旋转体的重量平衡。
(3.2)内销的自转结构
接下来，关于本基本结构的齿轮装置1的内销4的自转结构，参照图9更详细地进行说明。图9是图3的区域Z1的放大图。
首先作为前提，如上所述，多个内销4是将行星齿轮3与轴承构件6的内圈61连结的部件。具体而言，内销4的长度方向的一端部(在本基本结构中为旋转轴Ax1的输入侧的端部)插入于行星齿轮3的内销孔32，内销4的长度方向的另一端部(在本基本结构中为旋转轴Ax1的输出侧的端部)插入于内圈61的保持孔611。
此处，内销4的直径比内销孔32的直径小一圈，因此能够在内销4与 内销孔32的内周面321之间确保间隙，内销4能够在内销孔32内移动，也就是说内销4能够相对于内销孔32的中心相对地移动。另一方面，保持孔611的直径虽然为内销4的直径以上，但是比内销孔32的直径小。在本基本结构中，保持孔611的直径与内销4的直径大致相同，比内销4的直径稍大。因此，内销4在保持孔611内的移动被限制，也就是说内销4相对于保持孔611的中心的相对的移动被禁止。因此，对于内销4而言，在行星齿轮3中以在内销孔32内能够公转的状态被保持，且相对于内圈61以在保持孔611内不能公转的状态被保持。由此，行星齿轮3的摆动分量、也就是说行星齿轮3的公转分量被内销孔32与内销4的游嵌吸收，并通过多个内销4将除了行星齿轮3的摆动分量(公转分量)之外的、行星齿轮3的旋转(自转分量)向内圈61传递。
然而，在本基本结构中，内销4的直径比保持孔611稍大，由此内销4在插入于保持孔611的状态下，虽然在保持孔611内的公转被禁止，但是能够进行在保持孔611内的自转。也就是说，内销4即使是插入于保持孔611的状态，也因为不是被压入于保持孔611而能够在保持孔611内自转。这样，在本基本结构的齿轮装置1中，多个内销4各自以能够自转的状态由内圈61保持，因此在内销4在内销孔32内公转之际，内销4自身能够自转。
总之，在本基本结构中，内销4相对于行星齿轮3以能够进行在内销孔32内的公转及自转这两者的状态被保持，且相对于内圈61以仅能够进行在保持孔611内的自转的状态被保持。也就是说，多个内销4以各自的自转未被约束的状态(能够自转的状态)，能够以旋转轴Ax1为中心旋转(公转)，并且能够在多个内销孔32内公转。因此，在利用多个内销4将行星齿轮3的旋转(自转分量)向内圈61传递之际，内销4能够在内销孔32内进行公转及自转，且能够在保持孔611内进行自转。因此，内销4在内销孔32内公转之际，内销4处于能够自转的状态，因此相对于内销孔32 的内周面321进行滚动。换言之，内销4以在内销孔32的内周面321上滚转的方式在内销孔32内公转，因此难以产生因内销孔32的内周面321与内销4之间的摩擦阻力而引起的损失。
这样，在本基本结构的结构中，由于原本就难以产生因内销孔32的内周面321与内销4之间的摩擦阻力而引起的损失，因此能够省略内滚子。因此，在本基本结构中，多个内销4各自采用直接与内销孔32的内周面321接触的结构。也就是说，在本基本结构中，成为将未装配内滚子的状态的内销4插入于内销孔32从而使得内销4直接与内销孔32的内周面321接触的结构。由此，能够省略内滚子，能够将内销孔32的直径抑制得比较小，因此能够进行行星齿轮3的小型化(特别是小径化)，且作为齿轮装置1整体也容易实现小型化。如果将行星齿轮3的尺寸设为固定，则与上述第一关联技术相比，例如，还可以增加内销4的个数(根数)来使旋转的传递顺畅，或者使内销4变粗而提高强度。进一步，能够根据内滚子相应的量将部件个数抑制得少，从而也有助于齿轮装置1的低成本化。
另外，在本基本结构的齿轮装置1中，多个内销4各自的至少一部分在轴承构件6的轴向上配置于与轴承构件6相同的位置。也就是说，如图9所示，在与旋转轴Ax1平行的方向上，内销4将其至少一部分配置于与轴承构件6相同的位置。换言之，内销4的至少一部分位于与旋转轴Ax1平行的方向上的轴承构件6的两端面之间。再换言之，多个内销4各自将至少一部分配置于轴承构件6的外圈62的内侧。在本基本结构中，内销4中的旋转轴Ax1的输出侧的端部在与旋转轴Ax1平行的方向上处于与轴承构件6相同的位置。总之，内销4中的旋转轴Ax1的输出侧的端部插入于在轴承构件6的内圈61形成的保持孔611，因此至少该端部在轴承构件6的轴向上配置于与轴承构件6相同的位置。
这样，多个内销4各自的至少一部分在轴承构件6的轴向上配置与轴承构件6相同的位置，由此能够将与旋转轴Ax1平行的方向上的齿轮装置 1的尺寸抑制得小。也就是说，与轴承构件6和内销4沿轴承构件6的轴向并列(相对)的结构相比，在本基本结构的齿轮装置1中，能够减小与旋转轴Ax1平行的方向上的齿轮装置1的尺寸，并能够对齿轮装置1的进一步的小型化(薄型化)作出贡献。
此处，保持孔611中的旋转轴Ax1的输出侧的开口面例如由与内圈61一体化的输出轴等闭塞。由此，关于内销4向旋转轴Ax1的输出侧(图9的右侧)的移动，被与内圈61一体化的输出轴等限制。
另外，在本基本结构中，为了使得内销4相对于内圈61的自转顺畅地进行而采用以下的结构。即，通过使润滑剂(润滑油)介于在内圈61形成的保持孔611的内周面与内销4之间而使内销4的自转顺畅。特别是在本基本结构中，在内圈61与外圈62之间存在供润滑剂注入的润滑剂保持空间17，因此利用润滑剂保持空间17内的润滑剂实现内销4的自转的顺畅化。
如图9所示，在本基本结构中，内圈61具有：供多个内销4分别插入的多个保持孔611；和多个连结路64。多个连结路64使内圈61和外圈62之间的润滑剂保持空间17与多个保持孔611之间相连。具体而言，在内圈61形成有从保持孔611的内周面的一部分即与滚动体63对应的部位沿径向延伸的连结路64。连结路64是将内圈61的与外圈62相对的相对面中的收容滚动体63的凹部(槽)的底面与保持孔611的内周面之间贯通的孔。换言之，连结路64的润滑剂保持空间17侧的开口面配置于与轴承构件6的滚动体63面对(相对)的位置。润滑剂保持空间17与保持孔611经由这样的连结路64而在空间上相连。
根据上述结构，由于利用连结路64将润滑剂保持空间17与保持孔611连结，因此润滑剂保持空间17内的润滑剂穿过连结路64而被供给至保持孔611。也就是说，当轴承构件6动作而滚动滚动体63时，滚动体63作为泵发挥功能，能够将润滑剂保持空间17内的润滑剂经由连结路64送入至保持孔611。特别是连结路64的润滑剂保持空间17侧的开口面处于与轴承 构件6的滚动体63面对(相对)的位置，由此在滚动体63旋转时滚动体63作为泵有效地发挥作用。其结果是，润滑剂介于保持孔611的内周面与内销4之间，能够实现内销4相对于内圈61的自转的顺畅化。
(3.3)支承体
接下来，关于本基本结构的齿轮装置1的支承体8的结构，参照图10更详细地进行说明。图10是图3的B1-B1线剖视图。但是，在图10中，关于支承体8以外的部件，即使是剖面也省略剖面线。另外，在图10中，仅图示内齿齿轮2及支承体8，省略了其他的部件(内销4等)的图示。进一步，在图10中，省略了齿轮主体22的内周面221的图示。
首先作为前提，如上所述，支承体8是支承多个内销4的部件。也就是说，支承体8通过捆束多个内销4，从而分散将行星齿轮3的旋转(自转分量)向内圈61传递之际的、作用于多个内销4的载荷。具体而言，具有供多个内销4分别插入的多个支承孔82。在本基本结构中，作为一例，支承孔82的直径与形成于内圈61的保持孔611的直径相等。因此，支承体8以多个内销4各自能够自转的状态支承多个内销4。也就是说，多个内销4各自以相对于轴承构件6的内圈61与支承体8均能够自转的状态被保持。
这样，支承体8关于周向及径向这两个方向上，进行多个内销4的相对于支承体8的定位。也就是说，内销4通过插入于支承体8的支承孔82，从而与旋转轴Ax1正交的平面内的相对于全部方向的移动被限制。因此，内销4利用支承体8不仅在周向而且在径向(径向)也被定位。
此处，支承体8具有至少外周面81在俯视观察下为正圆的圆环状。并且，支承体8通过使外周面81与内齿齿轮2中的多个销23接触而被进行位置限制。多个销23由于构成内齿齿轮2的内齿21，所以换言之，支承体8通过使外周面81与内齿21接触而被进行位置限制。此处，支承体8的外周面81的直径与穿过内齿齿轮2的内齿21的前端的虚拟圆(齿顶圆)的直径相同。因此，多个销23全部与支承体8的外周面81接触。由此，在 支承体8由多个销23进行了位置限制的状态下，支承体8的中心以与内齿齿轮2的中心(旋转轴Ax1)重叠的方式被进行位置限制。由此，进行支承体8的定芯，结果是，关于由支承体8支承的多个内销4，也利用多个销23进行定芯。
另外，多个内销4以旋转轴Ax1为中心旋转(公转)，由此将行星齿轮3的旋转(自转分量)向内圈61传递。因此，对多个内销4进行支承的支承体8与多个内销4及内圈61一起以旋转轴Ax1为中心旋转。此时，支承体8利用多个销23进行定芯，因此以支承体8的中心被维持在旋转轴Ax1上的状态，支承体8顺畅地旋转。而且，支承体8以其外周面81与多个销23接触的状态旋转，因此伴随着支承体8的旋转，多个销23各自旋转(自转)。由此，支承体8与内齿齿轮2一起构成滚针轴承(针状滚子轴承)，并顺畅地旋转。
即，支承体8的外周面81以与多个销23相接的状态与多个内销4一起相对于齿轮主体22相对旋转。因此，如果将内齿齿轮2的齿轮主体22看作“外圈”，将支承体8看做“内圈”，则介于两者之间的多个销23作为“滚动体(滚子)”发挥功能。这样，支承体8与内齿齿轮2(齿轮主体22及多个销23)一起构成滚针轴承，并能够进行顺畅的旋转。
进一步，由于支承体8在齿轮主体22之间夹着多个销23，因此支承体8也作为抑制销23从齿轮主体22的内周面221分离的方向的移动的“限动件”发挥功能。也就是说，多个销23通过夹在支承体8的外周面81与齿轮主体22的内周面221之间，从而抑制多个销23从齿轮主体22的内周面221的浮起。总之，在本基本结构中，多个销23各自通过与支承体8的外周面81接触而被限制从齿轮主体22分离的方向的移动。
然而，如图9所示，在本基本结构中，支承体8隔着行星齿轮3而位于轴承构件6的与内圈61相反的一侧。也就是说，支承体8、行星齿轮3及内圈61沿与旋转轴Ax1平行的方向并列配置。在本基本结构中，作为一 例，支承体8在从行星齿轮3观察下位于旋转轴Ax1的输入侧，内圈61在从行星齿轮3观察下位于旋转轴Ax1的输出侧。并且，支承体8与内圈61一起支承内销4的长度方向(与旋转轴Ax1平行的方向)的两端部，内销4的长度方向的中央部贯通插入行星齿轮3的内销孔32。总之，本基本结构的齿轮装置1包括轴承构件6，该轴承构件6具有外圈62及配置于外圈62的内侧的内圈61，且内圈61被支承为能够相对于外圈62相对旋转。并且，齿轮主体22固定于外圈62。此处，行星齿轮3在支承体8的轴向上位于支承体8与内圈61之间。
根据该结构，支承体8及内圈61支承内销4的长度方向的两端部，因此难以产生内销4的倾斜。特别是也容易承受作用于多个内销4的对于旋转轴Ax1的弯曲力(弯曲力矩载荷)。另外，在本基本结构中，在与旋转轴Ax1平行的方向上，支承体8被夹在行星齿轮3与壳体10之间。由此，支承体8向旋转轴Ax1的输入侧(图9的左侧)的移动被壳体10限制。关于贯通支承体8的支承孔82而从支承体8向旋转轴Ax1的输入侧突出的内销4，向旋转轴Ax1的输入侧(图9的左侧)的移动也被壳体10限制。
在本基本结构中，支承体8及内圈61还与多个销23的两端部接触。也就是说，如图9所示，支承体8与销23的长度方向(与旋转轴Ax1平行的方向)的一端部(旋转轴Ax1的输入侧的端部)接触。内圈61与销23的长度方向(与旋转轴Ax1平行的方向)的另一端部(旋转轴Ax1的输出侧的端部)接触。根据该结构，支承体8及内圈61在销23的长度方向的两端部被定芯，因此难以产生内销4的倾斜。特别是也容易承受作用于多个内销4的对于旋转轴Ax1的弯曲力(弯曲力矩载荷)。
另外，多个销23具有支承体8的厚度以上的长度。换言之，在与旋转轴Ax1平行的方向上，支承体8收于内齿21的齿向的范围内。由此，支承体8的外周面81遍及内齿21的齿向方向(与旋转轴Ax1平行的方向)的全长地与多个销23接触。因此，难以产生支承体8的外周面81局部性地 磨损的“单边磨损”那样的不良状况。
另外，在本基本结构中，支承体8的外周面81比支承体8的与外周面81相邻的一表面表面粗糙度小。也就是说，外周面81的表面粗糙度比支承体8的轴向(厚度方向)的两端面小。本公开实施例所说的“表面粗糙度”是指物体的表面的粗糙程度，值越小则表面的凹凸越小(越少)越光滑。在本基本结构中，作为一例，将表面粗糙度设为算数平衡粗糙度(Ra)。例如，通过研磨等处理，外周面81比支承体8的外周面81以外的面的表面粗糙度小。在该结构中，支承体8的旋转变得更加顺畅。
另外，在本基本结构中，支承体8的外周面81的硬度比多个销23的周面低且比齿轮主体22的内周面221高。本公开实施例所说的“硬度”是指物体的坚硬程度，金属的硬度例如由以一定的压力推压钢球而形成的压痕的大小来表示。具体而言，作为金属的硬度的一例，有洛氏硬度(HRC)、布氏硬度(HB)、维氏硬度(HV)或肖氏硬度(Hs)等。作为提高金属部件的硬度(变硬)的手段，例如有合金化或热处理等。在本基本结构中，作为一例，通过渗碳淬火等处理来提高支承体8的外周面81的硬度。在该结构中，即使由于支承体8的旋转也难以产生磨损粉等，容易长期地维持支承体8的顺畅的旋转。
(4)适用例
接下来，说明本基本结构的齿轮装置1及执行器100的适用例。
本基本结构的齿轮装置1及执行器100例如适用于水平多关节机器人、即所谓的选择柔性组合机器人臂(SCARA：Selective Compliance Assembly Robot Arm)型机器人那样的机器人。
另外，本基本结构的齿轮装置1及执行器100的适用例并不限于上述那样的水平多关节机器人，例如，也可以是除了水平多关节机器人以外的产业用机器人或产业以外的机器人等。作为一例，水平多关节机器人以外的产业用机器人有垂直多关节型机器人或平行连杆型机器人等。在产业用 以外的机器人中，作为一例，有家庭用机器人、护理用机器人或医疗用机器人等。
(实施方式一)
＜概要＞
本实施方式的内啮合行星齿轮装置1A(以下，也简称为“齿轮装置1A”)如图11～图15等所示，主要是内销4周边的结构与基本结构的齿轮装置1不同。以下，关于与基本结构同样结构，标注相同的附图标记而适当省略说明。
图11是齿轮装置1A的概略剖视图。图12A是图11的区域Z1的概略放大图，图12B是图12A的A1-A1线剖视图。图13是示意性地表示在图12A的状态下作用的力的说明图。图14是从旋转轴Ax1的输出侧(图11的右侧)观察到的齿轮装置1A的侧视图，图11相当于图14的A1-A1线剖视图。图15是从旋转轴Ax1的输入侧(图11的左侧)观察到的齿轮装置1A的侧视图。
作为与基本结构第一个主要的不同点，本实施方式的齿轮装置1A构成为在多个内销4相对于内齿齿轮2为非旋转时，从行星齿轮3向各内销4作用预压力。也就是说，在齿轮装置1A中，在多个内销4相对于内齿齿轮2为非旋转时，多个内销孔32各自的内周面321向多个内销4的各个内销靠压，由此对多个内销4的各个内销作用有预压力(力F1、F2)。此处，齿轮装置1A还包括支承多个内销4的各个内销的支承结构40，以维持作用有预压力的状态。支承结构40支承多个内销4的各个内销，以抵消因预压力而产生于多个内销4的各个内销的力矩M1(参照图13)。
另外，作为本实施方式的齿轮装置1A的与基本结构的第二个主要的不同点，支承多个内销4的结构(支承结构40)是由滚动轴承41、42保持内销4的两端部的结构。也就是说，齿轮装置1A包括相对于行星齿轮3在与旋转轴Ax1平行的方向的两侧处保持多个内销4的各个内销的多组滚动轴 承41、42。多个内销4的各个内销以能够自转的状态由各组滚动轴承41、42保持。
总之，作为与基本结构主要的不同点，本实施方式的齿轮装置1A新采用了内销4周边的结构、特别是对于内销4的预压力的研究和关于内销4的支承结构40(滚动轴承41、42)的研究。此处，滚动轴承41、42固定于轴承构件6A的内圈61，内销4经由滚动轴承41、42由轴承构件6A的内圈61保持。因此，在本实施方式的齿轮装置1A中，关于多个内销4的各个内销以能够自转的状态由内圈61保持这点也与基本结构一样。
＜其他的不同点＞
本实施方式的齿轮装置1A中，除了上述的主要的不同点(内销4周边结构)之外，如以下说明那样，对于基本结构有多个不同点。
作为其他的第一个不同点，本实施方式的齿轮装置1A的轴承构件6A包含第一轴承构件601A及第二轴承构件602A。第一轴承构件601A及第二轴承构件602A分别由深沟球轴承构成，并具有内圈61、外圈62及多个滚动体63。第一轴承构件601A及第二轴承构件602A相对于行星齿轮3配置在与旋转轴Ax1平行的方向的两侧。第一轴承构件601A的内圈61及第二轴承构件602A的内圈61均具有外周面在俯视观察下是以旋转轴Ax1为中心的正圆的圆环状。具体而言，如图11所示，从行星齿轮3观察在旋转轴Ax1的输入侧(图11的左侧)配置有第一轴承构件601A，从行星齿轮3观察在旋转轴Ax1的输出侧(图11的右侧)配置有第二轴承构件602A。轴承构件6A利用第一轴承构件601A及第二轴承构件602A构成为径向的载荷、推力方向(沿着旋转轴Ax1的方向)的载荷、及对于旋转轴Ax1的弯曲力(弯曲力矩载荷)都能耐受。
作为其他的第二个不同点，如图11所示，本实施方式的齿轮装置1A包括支架凸缘18及输出凸缘19。支架凸缘18及输出凸缘19固定于轴承构件6A(第一轴承构件601A及第二轴承构件602A各自)的内圈61。支架 凸缘18及输出凸缘19相对于行星齿轮3配置在与旋转轴Ax1平行的方向两侧，并穿过行星齿轮3的支架孔34(参照图16)而相互结合。具体而言，如图11所示，从行星齿轮3观察在旋转轴Ax1的输入侧(图11的左侧)配置有支架凸缘18，从行星齿轮3观察在旋转轴Ax1的输出侧(图11的右侧)配置有输出凸缘19。对于支架凸缘18而言，通过嵌入第一轴承构件601A的内圈61而被固定，对于输出凸缘19而言，通过嵌入第二轴承构件602A的内圈61而被固定。
输出凸缘19具有从输出凸缘19的一表面朝向旋转轴Ax1的输入侧突出的多个(作为一例为6个)支架销191(参照图16)。这些多个支架销191分别贯通在行星齿轮3形成的多个(作为一例为6个)支架孔34，多个支架销191的前端利用支架螺栓181(参照图15)固定于支架凸缘18。此处，支架销191的直径比支架孔34的直径小一圈，且在支架销191与支架孔34的内周面之间确保间隙，支架销191能够在支架孔34内移动，也就是说能够相对于支架孔34的中心相对地移动。而且，支架销191与支架孔34的内周面的间隙比内销4与内销孔32的内周面321的间隙大，内销4在内销孔32内公转之际，支架销191不与支架孔34的内周面接触。另外，在输出凸缘19中的与支架销191相反的一侧的表面形成有用于将输出凸缘19自身固定的多个凸缘螺栓孔192(参照图14)。
此处，内销4的两端部不是直接由轴承构件6A的内圈61保持，而是由与内圈61一体化的支架凸缘18及输出凸缘19(经由滚动轴承41、42)保持。也就是说，多个内销4因由支架凸缘18及输出凸缘19保持而间接地由轴承构件6A的内圈61保持。
由此，齿轮装置1A以下述方式使用：将行星齿轮3的相当于自转分量的旋转作为与轴承构件6A的内圈61一体化的支架凸缘18及输出凸缘19的旋转而取出。即，在基本结构中，行星齿轮3与内齿齿轮2之间的相对的旋转从利用内销4连结于行星齿轮3的内圈61作为行星齿轮3的自转分 量取出。对此，在本实施方式中，行星齿轮3与内齿齿轮2之间的相对的旋转从与内圈61一体化的支架凸缘18及输出凸缘19取出。在本实施方式中，作为一例，齿轮装置1A以轴承构件6A的外圈62固定于作为固定构件的壳体的状态进行使用。即，行星齿轮3利用多个内销4与作为旋转构件的支架凸缘18及输出凸缘19连结，齿轮主体22固定于固定构件，因此行星齿轮3与内齿齿轮2之间的相对的旋转从旋转构件(支架凸缘18及输出凸缘19)取出。换言之，在本实施方式中，构成为多个内销4相对于齿轮主体22进行相对旋转之际，将支架凸缘18及输出凸缘19的旋转力作为输出取出。
作为其他的第三个不同点，在本实施方式中，壳体10与内齿齿轮2的齿轮主体22无缝地一体化。也就是说，在基本结构中，内齿齿轮2的齿轮主体22与轴承构件6的外圈62一起以固定于壳体10的状态使用。对此，在本实施方式中，在与旋转轴Ax1平行的方向上，作为固定构件的齿轮主体22与壳体10无缝地连续设置。
更详细而言，壳体10为圆筒状，且构成齿轮装置1A的外轮廓。在本实施方式中，圆筒状的壳体10的中心轴构成为与旋转轴Ax1一致。也就是说，壳体10的至少外周面在俯视观察下(从旋转轴Ax1方向的一方观察)是以旋转轴Ax1为中心的正圆。壳体10形成为在旋转轴Ax1方向的两端面开口的圆筒状。此处，壳体10与内齿齿轮2的齿轮主体22无缝地一体化，从而壳体10及齿轮主体22作为一个部件来处理。因此，壳体10的内周面包含齿轮主体22的内周面221。进一步，在壳体10固定有轴承构件6A的外圈62。也就是说，从壳体10的内周面中的齿轮主体22观察，第一轴承构件601A的外圈62通过嵌入而固定于旋转轴Ax1的输入侧(图11的左侧)。另一方面，从壳体10的内周面的齿轮主体22观察，第二轴承构件602A的外圈62通过嵌入而固定于旋转轴Ax1的输出侧(图11的右侧)。
进一步，壳体10的旋转轴Ax1的输入侧(图11的左侧)的端面由支 架凸缘18来闭塞，壳体10的旋转轴Ax1的输出侧(图11的右侧)的端面由输出凸缘19来闭塞。因此，如图11、图14及图15所示，在被壳体10、支架凸缘18及输出凸缘19包围的空间内，收容有行星齿轮3、多个内销4、多个销23、及偏心体轴承5等部件。此处，油封161填塞支架凸缘18与壳体10之间的间隙，油封162填塞输出凸缘19与壳体10之间的间隙。由多个油封14、15、161、162密闭的空间与基本结构同样地构成润滑剂保持空间17(参照图11)。在壳体10中的与旋转轴Ax1平行的方向的两端面形成有用于将壳体10自身固定的多个设置孔111。
作为其他的第四个不同点，本实施方式的齿轮装置1A包括多个行星齿轮3。具体而言，齿轮装置1A包括第一行星齿轮301和第二行星齿轮302这两个行星齿轮3。两个行星齿轮3配置为在与旋转轴Ax1平行的方向上(夹着支承环8A)相对。也就是说，行星齿轮3包含沿与旋转轴Ax1平行的方向并列的第一行星齿轮301及第二行星齿轮302。
这些两个行星齿轮3(第一行星齿轮301及第二行星齿轮302)绕着旋转轴Ax1以180度的位相差配置。在图11的例中，第一行星齿轮301及第二行星齿轮302中的、位于旋转轴Ax1的输入侧(图11的左侧)的第一行星齿轮301的中心C1处于相对于旋转轴Ax1向图的上方偏离(偏)的状态。另一方面，位于旋转轴Ax1的输出侧(图11的右侧)的第二行星齿轮302的中心C2处于相对于旋转轴Ax1向图的下方偏离(偏)的状态。这样，多个行星齿轮3在以旋转轴Ax1为中心的周向上均等地配置，由此能够取得多个行星齿轮3之间的重量平衡。在本实施方式的齿轮装置1A中，这样在多个行星齿轮3之间取得重量平衡，因此省略偏心轴7的空隙75(参照图3)。
更详细而言，偏心轴7对于一个轴心部71具有两个偏心部72。这些两个偏心部72的中心(中心轴)分别与从旋转轴Ax1偏离的中心C1、C2一致。另外，第一行星齿轮301及第二行星齿轮302的形状自身相同。并且， 在第一行星齿轮301的开口部33收容有装配于以中心C1为中心的偏心部72的状态的偏心体轴承5。在第二行星齿轮302的开口部33收容有装配于以中心C2为中心的偏心部72的状态的偏心体轴承5。此处，旋转轴Ax1与中心C1之间的距离ΔL1为第一行星齿轮301相对于旋转轴Ax1的偏心量，旋转轴Ax1与中心C2之间的距离ΔL2为第二行星齿轮302相对于旋转轴Ax1的偏心量。
在图16及图17中，示出某时刻的第一行星齿轮301及第二行星齿轮302的状态。图16是图11的A1-A1线剖视图，示出第一行星齿轮301。图17是图11的B1-B1线剖视图，示出第二行星齿轮302。其中，在图16及图17中，省略保持器54的图示，并且即使是剖面也省略剖面线。如图16及图17所示，在第一行星齿轮301与第二行星齿轮302中，它们的中心C1、C2相对于旋转轴Ax1位于180度旋转对称。在本实施方式中，对于偏心量ΔL1和偏心量ΔL2而言，从旋转轴Ax1观察到的朝向虽然相反，但是它们的绝对值相同。根据上述的结构，轴心部71以旋转轴Ax1为中心旋转(自转)，由此第一行星齿轮301及第二行星齿轮302绕着旋转轴Ax1以180度的位相差地绕着旋转轴Ax1旋转(偏心运动)。
作为其他的第五个不同点，如图11所示，在本实施方式中，偏心体轴承5由滚子轴承构成来代替基本结构所说明的那样的深沟球轴承。也就是说，在本实施方式的齿轮装置1A中，偏心体轴承5使用圆柱状(圆筒状)的滚子作为滚动体53。进一步，在本实施方式中，省略了偏心体内圈51(参照图3)及偏心体外圈52(参照图3)。因此，行星齿轮3(的开口部33)的内周面代替偏心体外圈52成为多个滚动体53的滚动面，偏心部72的外周面代替偏心体内圈51成为多个滚动体53的滚动面。在本实施方式中，偏心体轴承5具有保持器(retainer)54，多个滚动体53各自以能够自转的状态保持于保持器54。保持器54在偏心部72的圆周方向上等间距地保持多个滚动体53。进一步，保持器54相对于行星齿轮3及偏心轴7不固定， 而是能够相对于行星齿轮3及偏心轴7各自进行相对旋转。由此，伴随着保持器54的旋转，由保持器54保持的多个滚动体53向偏心部72的圆周方向移动。
作为其他的第六个不同点，如图11所示，本实施方式的齿轮装置1A包括支承环8A来代替支承体8。支承环8A配置于第一行星齿轮301和第二行星齿轮302这两个行星齿轮3之间。支承环8A具有至少外周面在俯视观察下为正圆的圆环状。并且，支承环8A通过使外周面与内齿齿轮2的多个销23接触而被进行位置限制。多个销23由于构成内齿齿轮2的内齿21，所以换言之，支承环8A通过使外周面与内齿21接触而被进行位置限制。此处，支承环8A的外周面的直径与穿过内齿齿轮2的内齿21的前端的虚拟圆(齿顶圆)的直径相同。因此，多个销23全部与支承环8A的外周面接触。由此，在支承环8A由多个销23进行了位置限制的状态下，支承环8A的中心以与内齿齿轮2的中心(旋转轴Ax1)重叠的方式被进行位置限制。
此处，支承环8A被第一行星齿轮301与第二行星齿轮302夹持，且伴随着行星齿轮3的旋转(自转)以旋转轴Ax1为中心旋转。此时，支承环8A以其外周面与多个销23接触的状态旋转，因此伴随着支承环8A的旋转，多个销23各自旋转(自转)。由此，支承环8A与内齿齿轮2一起构成滚针轴承(针状滚子轴承)，并顺畅地旋转。即，如果将内齿齿轮2的齿轮主体22看做“外圈”，将支承环8A看做“内圈”，则介于两者之间的多个销23作为“滚动体(滚子)”发挥功能。这样，支承环8A与内齿齿轮2(齿轮主体22及多个销23)一起构成滚针轴承，并能够进行顺畅的旋转。进一步，由于支承环8A在与齿轮主体22之间夹着多个销23，因此支承环8A也作为抑制销23从齿轮主体22的内周面221分离的方向的移动的“限动件”发挥功能。
作为其他的第七个不同点，如图11所示，本实施方式的齿轮装置1A 包括间隔件55。间隔件55配置于作为内侧轴承构件的第一轴承91及第二轴承92与偏心体轴承5之间。具体而言，间隔件55分别配置于第一轴承91与第一行星齿轮301侧的偏心体轴承5之间，及第二轴承92与第二行星齿轮302侧的偏心体轴承5之间。间隔件55具有至少内周面在俯视观察下为正圆的圆环状。间隔件55作为偏心体轴承5的“按压件”发挥功能，并限制偏心体轴承5(特别是保持器54)向与旋转轴Ax1平行的方向的移动。
此处，间隔件55相对于第一轴承91及第二轴承92在与它们的外圈之间确保间隙。因此，在第一轴承91及第二轴承92中，它们的外圈不与间隔件55相接，而仅是它们的内圈与间隔件55接触。另一方面，作为轴承构件6A的第一轴承构件601A及第二轴承构件602A相对于行星齿轮3在与它们的外圈62之间确保间隙。因此，在第一轴承构件601A及第二轴承构件602A中，它们的外圈62不与行星齿轮3相接，而仅是它们内圈61与行星齿轮3接触。并且，在行星齿轮3中与第一轴承构件601A及第二轴承构件602A的内圈61相接，由此行星齿轮3的向与旋转轴Ax1平行的方向的移动被限制，从而抑制行星齿轮3的倾斜。
另外，除了上述的点以外，例如，关于内齿齿轮2及行星齿轮3的齿数、减速比、内销孔32及内销4的个数乃至各部分的具体的形状及尺寸等，在本实施方式与基本结构中也适当不同。例如，关于内销孔32及内销4，在基本结构中各设置18个，而对此，在本实施方式中，作为一例，各设置6个。
＜内销周边的结构＞
接下来，关于本实施方式的齿轮装置1A中的、内销4周边的结构，参照图11～图18更详细地进行说明。
如上所述，在本实施方式中，在多个内销4相对于内齿齿轮2为非旋转时，多个内销孔32各自的内周面321向多个内销4的各个内销靠压，由此从行星齿轮3对多个内销4的各个内销作用有预压力(力F1、F2)。并且， 支承结构40支承各内销4，以抵消因该预压力而产生于各内销4的力矩。
本公开实施例所说的“预压力”是指通过作用预先压力而处于始终作用有内部应力的状态，是所谓的预负载(preload)。即，在本实施方式的齿轮装置1A中，在多个内销4相对于内齿齿轮2为非旋转时，也就是说在不驱动齿轮装置1A的状态下，从行星齿轮3向各内销4作用预压力。总之，在本实施方式中，多个内销4相对于内齿齿轮2旋转时(齿轮装置1A的驱动时)自不必说，即使是多个内销4相对于内齿齿轮2为非旋转时(齿轮装置1A的非驱动时)，内销孔32的内周面321也靠压于内销4。
根据上述结构，在本实施方式的齿轮装置1A中，内销4始终在内销孔32的内周面321的一部分处与行星齿轮3接触，难以产生内销4与行星齿轮3分离的状态。因此，如果驱动齿轮装置1A，则内销4以靠压于内销孔32的内周面321的状态在内销孔32内公转。一般来说，在考虑组装公差等来组装齿轮装置的状态下，在齿轮装置为非驱动时，在内销孔的内周面与内销之间确保间隙，但是本实施方式的齿轮装置1A敢于构成为消除该间隙。因此，根据本实施方式的齿轮装置1A，能够减少或消除至少因内销孔32的内周面321与内销4之间的间隙而产生的齿隙(Backlash)，从而容易将角度传递误差抑制得小。特别是在高的减速比的齿轮装置1A中，即使是因稍稍的间隙而产生的齿隙，输出侧(输出凸缘19)的旋转相对于输入侧(偏心轴7)的旋转的误差、也就是说角度传递误差也会变大，因此减少或消除齿隙的效果大。
进一步，根据本实施方式的结构，能够减小齿轮装置1A从停止的状态到开始旋转的启动时的角度传递误差，因此能够大幅地改善作为齿轮装置1A的启动特征，从而大幅地提高齿轮装置1A的启动时或者旋转方向切换时的响应性。其结果是，例如如机器人领域那样，即使是频繁地进行停止、启动或者旋转方向的切换，并且对角度传递误差的要求严格的领域，只要是齿轮装置1A也能够发挥充分的特性。
而且，在本实施方式中，多个内销4各自以能够自转的状态由内圈61保持。但是，严格来说，各内销4不是直接由内圈61保持，而是由与内圈61一体化的支架凸缘18及输出凸缘19(经由滚动轴承41、42)保持，由此由轴承构件6A的内圈61间接地保持。这样，根据内销4被保持为能够自转的结构，即使内销4以靠压于内销孔32的内周面321的状态在内销孔32内公转，内销4由于处于能够自转的状态，因此也相对于内销孔32的内周面321滚动。换言之，内销4以在内销孔32的内周面321上滚转的方式在内销孔32内公转，因此不易产生因内销孔32的内周面321与内销4之间的摩擦阻力而引起的损失。
另外，如图12A所示，在本实施方式中，支承结构40包含相对于行星齿轮3在与旋转轴Ax1平行的方向的两侧处保持多个内销4的各个内销的多组保持部410、420。总之，支承各内销4的支承结构40包含多组保持部410、420，以消除因该预压力而产生于各内销4的力矩。各组保持部410、420相对于行星齿轮3在与旋转轴Ax1平行的方向的两侧保持各内销4。保持部410、420设置为与内销4的根数相同的组数，在本实施方式中，作为一例，与6根内销4对应地设置6组保持部410、420。
具体而言，各组保持部410、420保持内销4的长度方向的两端部。从行星齿轮3观察在旋转轴Ax1的输入侧(图12A的左侧)配置有保持部410，从行星齿轮3观察在旋转轴Ax1的输出侧(图12A的右侧)配置有保持部420。
此处，多组保持部410、420的各组包含一对滚动轴承41、42。在本实施方式中，保持部410由滚动轴承41构成，保持部410由滚动轴承41构成。也就是说，一对滚动轴承41、42构成各组保持部410、420。因此，在本实施方式中，作为一例，一对滚动轴承41、42设置与保持部410、420相同的数量的6组。滚动轴承41通过压入于支架凸缘18而固定，滚动轴承42通过压入于输出凸缘19而固定。
具体而言，一对滚动轴承41、42将内销4的长度方向的两端部保持为内销4能够自转的状态。此处，如图12A及图12B所示，各滚动轴承41、42具有外圈401及多个滚动体402。如图12B所示，外圈401是环状的部件。外圈401具有俯视观察下为正圆的圆环状。此处，外圈401的内径比内销4的直径(外径)大一圈，因此在外圈401的内周面与内销4的外周面之间产生间隙。多个滚动体402配置于外圈401与内销4之间的间隙。多个滚动体402沿外圈401的圆周方向并列配置。多个滚动体402全部为同一形状的金属部件，在外圈401的圆周方向的整个区域等间距地设置。
在本实施方式中，作为一例，各滚动轴承41、42是滚针轴承(针状滚子轴承)。也就是说，各滚动轴承41、42具有圆筒状的滚子作为滚动体402。并且，圆筒状的滚动体402的轴均配置成平行于旋转轴Ax1。在本实施方式中，各滚动轴承41、42不具有内圈，内销4作为内圈发挥功能。因此，根据各滚动轴承41、42，多个滚动体402进行滚动，由此内销4相对于外圈401旋转，从而各滚动轴承41、42能够将内销4保持为能够自转。
总之，如上所述，本实施方式的齿轮装置1A包括相对于行星齿轮3在与旋转轴Ax1平行的方向的两侧处保持多个内销4各自的多组滚动轴承41、42。多个内销4各自以能够自转的状态由组滚动轴承41、42保持。根据该结构，内销4能够自转，由于原本就不易产生因内销孔32的内周面321与内销4之间的摩擦阻力而引起的损失，因此能够省略内滚子。因此，在本实施方式中，成为将未装配内滚子的状态的内销4插入于内销孔32从而内销4直接与内销孔32的内周面321接触的结构。由此，能够省略内滚子，能够将内销孔32的直径抑制得比较小，因此能够进行行星齿轮3的小型化(特别是小径化)，且作为齿轮装置1A整体也容易实现小型化。而且，保持各内销4的保持部410、420包含一对滚动轴承41、42。因此，在内销4旋转之际，不易产生因内销4与保持部410、420之间的摩擦阻力而引起的损失。
特别是，内销4将行星齿轮3与旋转构件(支架凸缘18及输出凸缘19)连结，至少在齿轮装置1A驱动时，对内销4作用弯曲力(弯曲力矩载荷)。因此，例如，在利用滑动轴承保持内销4的情况下，因该弯曲力而内销4与保持部410、420之间的摩擦阻力变大，从而因该摩擦阻力而引起的损失变大。对此，在本实施方式中，保持部410、420包含滚动轴承41、42，由此即使对内销4作用弯曲力，也难以影响内销4与保持部410、420之间的摩擦阻力，从而不易产生因摩擦阻力而引起的损失。
进一步，如上所述，在本实施方式的齿轮装置1A中，在多个内销4相对于内齿齿轮2为非旋转时，将多个内销孔32的各自的内周面321向多个内销4各的各个内销靠压，由此从行星齿轮3对多个内销4的各个内销作用预压力(力F1、F2)。在将这样的预压力作用于内销4的情况下，对内销4作用的弯曲力(弯曲力矩载荷)变得更大。因此，本实施方式的齿轮装置1A那样，通过保持部410、420包含滚动轴承41、42，从而即使大的弯曲力作用于内销4，对于难以影响内销4与保持部410、420之间的摩擦阻力的结构而言也特别有用。
接下来，参照图13，关于在多个内销4相对于内齿齿轮2为非旋转时、也就是说齿轮装置1A的非驱动时，作用于内销4的力(预压力)，更详细地进行说明。
此处，从两个行星齿轮3(第一行星齿轮301及第二行星齿轮302)对各内销4作用相互相反朝向的力。例如，在图13所示的状态下，从第一行星齿轮301对内销4作用向上的力F1，从第二行星齿轮302对内销4作用朝下的力F2，因此在内销4作用有顺时针的力矩M1。另一方面，各内销4的两端部由保持部410、420(一对滚动轴承41、42)保持，因此在力矩M1的作用下，在内销4的两端部作用有来自保持部410、420的反作用力F3、F4。因此，内销4的表面与滚动轴承41、42的滚动体402的表面在反作用力F3、F4的作用下相互靠压地进行弹性接触。结果是，通过在内销4 及滚动体402的表面之间作用有赫兹(Hertz)的接触应力(施加于弹性接触部分的应力或压力)，从而在内销4及滚动体402产生弹性变形。
另外，当将力F1(或F2)与反作用力F3(或F4)进行比较时，反作用力F3(或F4)比力F1(或F2)小(F3＜F1、或F4＜F2)。也就是说，反作用力F3与力F1的比由从力矩M1的中心到力F1的作用点为止的距离(L2)与到反作用力F3的作用点为止的距离(L1)之比来表示(F3：F1＝L2：L1)。因此，施加于滚动体402的载荷变得比较小，由赫兹的接触应力而产生的内销4及滚动体402的变形量也变得比较小。
在该状态下，内销4作为梁的由弹性变形而引起的变形量比由赫兹的接触应力而引起的变形量大。因此，即使产生由赫兹的接触应力而引起的弹性变形，通过至少内销4自身的弹性变形，从内销4作用于行星齿轮3(第一行星齿轮301及第二行星齿轮302)的力(反作用力)也可维持在恒定以上。换言之，内销4相对于第一行星齿轮301的内销孔32的内周面321、及第二行星齿轮302的内销孔32的内周面321维持靠压的状态。结果是，维持从行星齿轮3作用于内销4的“预压力”。
这样，在本实施方式的齿轮装置1A中，通过产生于多个内销4各自的弯曲力矩而作用预压力。即，在本实施方式中，利用因作用于内销4的弯曲力矩而内销4进行弹性变形所引起的变形量比由赫兹的接触应力而引起的变形量大这一情况来维持“预压力”。换言之，利用内销4自身的弹性，使内销孔32的内周面321向内销4靠压，由此使预压力从行星齿轮3作用于内销4。因此，除内销4以外，无需设置用于产生预压力的其他部件就能够将部件个数抑制得少，因此，结果是有助于齿轮装置1A的小型化。
然而，上述那样的预压力通过设于内销4与内销孔32的内周面321之间的负的间隙(负间隙)来实现。本公开实施例所说的“负的间隙”是指所谓的“过盈量”，若按照两者间的设计的组装则两者称为相互重复(靠压)的关系。例如，如果在内销4与内销孔32的内周面321之间设置“X”的 负的间隙(-X)，则从旋转轴Ax1方向观察，在理论上，内销4处于从内销孔32的内周面321向内销孔32的外侧伸出“X”的状态。也就是说，在内销4与行星齿轮3的组装之际，为避免在内销4与内销孔32的内周面321之间产生正的间隙，通过使得该间隙为0以下来实现内销孔32的内周面321对内销4按压的状态。其结果是，在使内销4与行星齿轮3组合的状态下，即使是在多个内销4相对于内齿齿轮2为非旋转时，从行星齿轮3也对内销4作用有预压力(力F1、F2)。
在本实施方式中，作为一例，通过设置于多个内销4各自与多个内销孔32各自的内周面321之间的、内销4各自的直径的100分之一以下的负的间隙来作用预压力。总之，在本实施方式中，将用于实现预压力的负的间隙的大小设为0以上并且为内销4各自的直径的100分之一以下。作为一例，在销23的直径为5mm左右的情况下，内销4与内销孔32的内周面321之间的负的间隙优选为0mm以上且0.05mm以下。进一步，内销4与内销孔32的内周面321之间的负的间隙的大小优选为内销4的直径的200分之一，更优选为300分之一以下。
在本实施方式中，对于多个(此处为6个)内销4，一律设定负的间隙。因此，在多个内销4相对于内齿齿轮2为非旋转时，通过将多个内销孔32各自的内周面321向多个内销4全部靠压，由此从行星齿轮3作用预压力。但是，该结构对于齿轮装置1A而言不是必需设置的结构，也可以对多个内销4的一部分不作用预压力。
另外，在本实施方式中，不仅从行星齿轮3，也从滚动轴承41、42对内销4作用预压力。也就是说，关于保持内销4的一对滚动轴承41、42，也在多个滚动体402与内销4之间设定负的间隙。具体而言，外圈401的内径与内销4的径(直径)之差为滚动体402的径(直径)的2倍以下。由此，在内销4与滚动体402之间产生0以上的负的间隙(过盈量)。作为一例，内销4相对于滚动轴承41、42的嵌合公差优选为“k6”以上，更优 选为“p6”。总之，多组滚动轴承41、42各自具有多个滚动体402。通过靠压多个滚动体402从而向多个内销4的各个内销作用内销侧预压力。
根据该结构，减小或消除内销4与作为保持部410、420的滚动轴承41、42之间的间隙，能够抑制因该间隙而引起的内销4的晃动。结果是，根据本实施方式的齿轮装置1A，能够减少或消除因内销4与滚动轴承41、42之间的间隙而产生的齿隙(Backlash)，从而容易将角度传递误差抑制得小。
在本实施方式中，对于多个(此处为6个)内销4，对于滚动轴承41、42，一律设定负的间隙。因此，从滚动轴承41、42两者对多个内销4全部作用内销侧预压力。但是，该结构对于齿轮装置1A而言不是必需设置的结构，也可以对多个内销4的一部分不作用内销侧预压力。
以下，关于本实施方式的滚动轴承41、42的配置，更详细地进行说明。
首先，如图11所示，关于与旋转轴Ax1平行的方向上的多组滚动轴承41、42的配置，处于与第一轴承91及第二轴承92至少一部分重叠的位置。也就是说，在与旋转轴Ax1平行的方向上，滚动轴承41的至少一部分处于与第一轴承91相同的位置，滚动轴承42的至少一部分处于与第二轴承92相同的位置。特别是在本实施方式中，第一轴承91及第二轴承92各自的宽度方向(与旋转轴Ax1平行的方向)的尺寸比滚动轴承41、42各自的宽度方向的尺寸小。因此，在与旋转轴Ax1平行的方向上，在滚动轴承41、42各自的范围内，收有第一轴承91及第二轴承92的各个轴承。换言之，在滚动轴承41、42各自的内侧配置有第一轴承91及第二轴承92的各个轴承。
这样，本实施方式的齿轮装置1A包括内侧轴承构件(第一轴承91及第二轴承92)，该内侧轴承构件将使行星齿轮3进行偏心摆动的偏心轴7保持为相对于内圈61能够旋转。此处，在与旋转轴Ax1平行的方向上，多组滚动轴承41、42的至少一部分处于与内侧轴承构件(第一轴承91及第二轴承92)相同的位置。也就是说，第一轴承91及第二轴承92构成经由支 架凸缘18及输出凸缘19将使行星齿轮3进行偏心摆动的偏心轴7保持为相对于(轴承构件6A)的内圈61能够旋转的“内侧轴承构件”。这样，在本实施方式中，将原本设置于齿轮装置1A的内侧轴承构件(第一轴承91及第二轴承92)外侧的空间用作滚动轴承41、42的设置空间。因此，能够抑制因设置滚动轴承41、42而引起的、与旋转轴Ax1平行的方向上的齿轮装置1A的尺寸的增大。
进一步，如图11所示，关于与旋转轴Ax1平行的方向上的多组滚动轴承41、42的配置，第一轴承构件601A及第二轴承构件602A处于至少一部分重复的位置。也就是说，在与旋转轴Ax1平行的方向上，滚动轴承41的至少一部分处于与第一轴承构件601A相同的位置，滚动轴承42的至少一部分处于与第二轴承构件602A相同的位置。特别是在本实施方式中，第一轴承构件601A及第二轴承构件602A各自的宽度方向(与旋转轴Ax1平行的方向)的尺寸与滚动轴承41、42各自的宽度方向的尺寸大致相同。因此，在与旋转轴Ax1平行的方向上，在滚动轴承41、42各自的范围内，收有第一轴承构件601A及第二轴承构件602A的各个轴承构件。换言之，在滚动轴承41、42各自的外侧设置第一轴承构件601A及第二轴承构件602A的各个轴承构件。
这样，本实施方式的齿轮装置1A在与旋转轴Ax1平行的方向上，多组滚动轴承41、42的至少一部分处于与轴承构件6A(第一轴承构件601A及第二轴承构件602A)相同的位置。这样，在本实施方式中，将原本设置于齿轮装置1A的轴承构件6A(第一轴承构件601A及第二轴承构件602A)的内侧的空间用作滚动轴承41、42的设置空间。因此，能够抑制因设置滚动轴承41、42而引起的、与旋转轴Ax1平行的方向上的齿轮装置1A的尺寸的增大。
特别是在本实施方式中，滚动轴承41、42配置于内侧轴承构件(第一轴承91及第二轴承92)的外侧且轴承构件6A(第一轴承构件601A及第 二轴承构件602A)的内侧。换言之，滚动轴承41、42利用内侧轴承构件(第一轴承91及第二轴承92)与轴承构件6A(第一轴承构件601A及第二轴承构件602A)之间的空间进行配置。因此，能够抑制因设置滚动轴承41、42而引起的、径向(与旋转轴Ax1正交的方向)上的齿轮装置1A的尺寸的增大。
另一方面，关于从与旋转轴Ax1平行的方向观察到的多组滚动轴承41、42的配置，基本上与多个内销4的配置同样。即，如图16及图17所示，从与旋转轴Ax1平行的方向观察，设定穿过多个内销4各自的中心的虚拟圆VC1的情况下，多组滚动轴承41、42配置于虚拟圆VC1上。在本实施方式中，特别如图18所示，从与旋转轴Ax1平行的方向观察，多组滚动轴承41、42在绕着旋转轴Ax1的圆周方向上等间隔地配置。在图18中，示出滚动轴承41的配置，且滚动轴承42的配置也同样。另外，在图18中，即使是剖面也省略剖面线。
即，多组滚动轴承41、42在虚拟圆VC1上沿虚拟圆VC1的圆周方向等间隔地配置。也就是说，从与旋转轴Ax1平行的方向观察，虚拟圆VC1穿过多个滚动轴承41(或42)各自的中心，并且相邻的两个滚动轴承41(或42)间的在虚拟圆VC1上的距离对于多个滚动轴承41(或42)而言为均匀。根据该配置，由多组滚动轴承41、42保持多个内销4，且在齿轮装置1A驱动时，能够将施加于多个内销4的力均等地分散。
进一步，如图18所示，在本实施方式中，从与旋转轴Ax1平行的方向观察，穿过多组滚动轴承41、42的中心的虚拟圆VC1的中心与旋转轴Ax1一致。换言之，虚拟圆VC1的中心与内齿齿轮2的齿轮主体22的中心、或者内齿21的节圆的中心等相等，处于旋转轴Ax1上。根据该结构，内齿齿轮2的齿轮主体22的中心与多个内销4相对于内齿齿轮2的旋转中心容易高精度地维持于旋转轴Ax1上。其结果，在齿轮装置1A中，有不易产生因定芯不佳而引起的振动的产生及传递效率的下降等的不良状况这样的优 点。
＜适用例＞
如图19所示，本实施方式的齿轮装置1A与第一构件201及第二构件202一起构成机器人用关节装置200。换言之，本实施方式的机器人用关节装置200包括齿轮装置1A、第一构件201和第二构件202。第一构件201由外圈62固定。第二构件202由内圈61固定。图19是图13的相当于B1-B1线剖视图的机器人用关节装置200的概略图。在图19中，示意性地示出第一构件201及第二构件202。
在本实施方式中，作为一例，第一构件201固定于在壳体10形成的多个设置孔111，由此相对于轴承构件6A的外圈62间接地固定。第二构件202相对于在输出凸缘19形成的多个凸缘螺栓孔192固定，由此相对于轴承构件6A的内圈61间接地固定。
如此构成的机器人用关节装置200通过将第一构件201与第二构件202以旋转轴Ax1为中心相对旋转，从而作为关节装置发挥功能。此处，通过由驱动源101(参照图1)驱动齿轮装置1A的偏心轴7，从而第一构件201与第二构件202相对旋转。此时，驱动源101所产生的旋转(输入旋转)在齿轮装置1A中以比较高的减速比被减速，而以比较高的力矩驱动第一构件201或第二构件202。也就是说，由齿轮装置1A连结的第一构件201与第二构件202以旋转轴Ax1为中心能够进行屈伸动作。
机器人用关节装置200例如用于水平多关节机器人(关节型机器人)这样的机器人。进一步，机器人用关节装置200并不限于水平多关节机器人，例如，也可以用于除水平多关节机器人以外的产业用机器人、或者除产业用以外的机器人等。另外，本实施方式的齿轮装置1A并不限于机器人用关节装置200，例如，作为轮毂电机等车轮装置，也可以用于无人搬运车(AGV：Automated Guided Vehicle)等车辆。
＜变形例＞
实施方式一只不过是本公开实施例的各种实施方式的一个。实施方式一只要能够实现本公开实施例的目的，就可以根据设计等进行各种变更。另外，本公开实施例中所参照的附图均为示意图，图中的各结构要素的大小和厚度各自的比不一定限于反映实际的尺寸比。以下，列举实施方式一的变形例。以下所说明的变形例可适当组合而应用。
在实施方式一中，例示了行星齿轮3为两个类型的齿轮装置1A，但是齿轮装置1A可以包括三个以上行星齿轮3。例如，在齿轮装置1A包括三个行星齿轮3的情况下，优选这三个行星齿轮3绕着旋转轴Ax1以120度的位相差配置。另外，齿轮装置1A也可以仅包括一个行星齿轮3。或者，在齿轮装置1A包括三个行星齿轮3的情况下，也可以使这些三个行星齿轮3中的两个行星齿轮3为相同位相，剩余的一个行星齿轮3绕着旋转轴Ax1以180度的位相差配置。在该情况下，三个行星齿轮3自身作为支承多个内销4各自的“支承构件”发挥功能，以抵消因预压力而产生于多个内销4的各个内销的力矩M1(参照图13)。
另外，关于内销4，其两端部并不是必须由保持部410、420(滚动轴承41、42)保持，也可以仅一端部由保持部410、420(滚动轴承41、42)保持。
另外，在与旋转轴Ax1平行的方向上，多组滚动轴承41、42也可以不处于与内侧轴承构件(第一轴承91及第二轴承92)相同的位置。例如，多组滚动轴承41、42也可以配置为在与旋转轴Ax1平行的方向与内侧轴承构件(第一轴承91及第二轴承92)并列。同样，在与旋转轴Ax1平行的方向上，多组滚动轴承41、42也可以不处于与轴承构件6A(第一轴承构件601A及第二轴承构件602A)相同的位置。例如，多组滚动轴承41、42也可以配置为在与旋转轴Ax1平行的方向与轴承构件6A(第一轴承构件601A及第二轴承构件602A)并列。
另外，从与旋转轴Ax1平行的方向观察，多组滚动轴承41、42也可以 不在旋转轴Ax1周围的圆周方向上等间隔地配置。进一步，从与旋转轴Ax1平行的方向观察，穿过多组滚动轴承41、42的中心的虚拟圆VC1的中心也可以不与旋转轴Ax1一致。
另外，实施方式一所说明的内销4的个数及销23的个数(内齿21的齿数)、及外齿31的齿数等只不过为一例，可以适当变更。
另外，轴承构件6A与基本结构同样既可以是交叉滚子轴承，也可以是角接触球轴承等。但是，轴承构件6A优选例如四点接触球轴承等那样对于径向的载荷、推力方向(沿着旋转轴Ax1的方向)的载荷、及对于旋转轴Ax1的弯曲力(弯曲力矩载荷)都能耐受。
另外，偏心体轴承5并不局限于滚子球轴承，例如，也可以为深沟球轴承或角接触球轴承等。
另外，齿轮装置1A的各结构要素的材质并不限于金属，例如，可以为工程塑料等树脂。
另外，齿轮装置1A只要是能够将轴承构件6的内圈61与外圈62之间的相对的旋转作为输出取出即可，并不限于将内圈61(支架凸缘18及输出凸缘19)的旋转力作为输出取出的结构。例如，也可以将相对于内圈61相对旋转的外圈62(壳体10)的旋转力作为输出取出。
另外，润滑剂并不限于润滑油(油液)等液状的物质，可以是润滑脂等凝胶状的物质。
另外，齿轮装置1A可以包括内滚子。也就是说，在齿轮装置1A中，多个内销4各自不是必须与内销孔32的内周面321直接接触，也可以在多个内销4各自与内销孔32之间夹设内滚子。在这样的情况下，内滚子装配于内销4而能够以内销4为轴进行旋转。
另外，多个内销4各自只要以能够自转的状态保持于内圈61即可，多个内销4各自由滚动轴承41、42保持的情况在齿轮装置1A中不是必须的。例如，多个内销4各自既可以由内圈61直接保持，也可以由与内圈61一 体化的支架凸缘18或输出凸缘19等直接保持。
另外，支承环8A在齿轮装置1A不是必需的，既可以适当省略支承环8A，也可以使用基本结构所说明的支承体8来代替支承环8A。
另外，齿轮装置1A只要采用对于内销4的预压力的研究、关于内销4的支承结构40的研究的至少一者即可，无需采用这两者。即，齿轮装置1A可仅采用通过将内销孔32的内周面321向内销4靠压从而作用预压力的情况(对于内销4的预压力的研究)、配备保持内销4的滚动轴承41、42的情况(关于内销4的支承结构40的研究)中的任一者即可。
进一步，齿轮装置1A只要采用对于内销4的预压力的研究、关于内销4的支承结构40的研究的至少一者即可，因此关于其他的结构，可以根据基本结构进行适当省略或变更。例如，在齿轮装置1A中，与第一关联技术同样，内销4也可以在相对于内圈61(或与内圈61一体化的支架凸缘18或输出凸缘19)以压入的状态保持。在这样的情况下，多个内销4各自相对于内圈61以无法自转的状态保持。另外，多个内销4各自只要在轴承构件6A的轴向上配置于与轴承构件6A相同的位置即可。
(总结)
如以上说明所述，第一形态的内啮合行星齿轮装置(1、1A)包括轴承构件(6、6A)、内齿齿轮(2)、行星齿轮(3)、多个内销(4)和多组滚动轴承(41、42)。轴承构件(6、6A)具有外圈(62)及配置于外圈(62)的内侧的内圈(61)，将内圈(61)支承为能够相对于外圈(62)以旋转轴(Ax1)为中心相对旋转。内齿齿轮(2)具有内齿(21)且固定于外圈(62)。行星齿轮(3)具有与内齿(21)局部性地啮合的外齿(31)。多个内销(4)在分别插入到在行星齿轮(3)形成的多个内销孔(32)的状态下，一边在内销孔(32)内公转一边相对于内齿齿轮(2)相对旋转。多组滚动轴承(41、42)相对于行星齿轮(3)在与旋转轴(Ax1)平行的方向的两侧处保持多个内销(4)的各个内销。多个内销(4)的各个内销以能够自转的状态而 由各组滚动轴承(41、42)保持。
根据该结构，内销(4)能够自转，且不易产生因内销孔(32)的内周面(321)与内销(4)之间的摩擦阻力而引起的损失，因此能够省略内滚子。因此，由于能够省略内滚子，且能够将内销孔(32)的直径抑制得比较小，所以能够进行行星齿轮(3)的小型化，且作为内啮合行星齿轮装置(1、1A)整体也容易实现小型化。而且，内销(4)相对于行星齿轮(3)在与旋转轴(Ax1)平行的方向的两侧处，通过滚动轴承(41、42)来保持，因此在内销(4)旋转之际不易产生因摩擦阻力而引起的损失。
第二形态的内啮合行星齿轮装置(1、1A)，在第一形态的基础上，还包括内侧轴承构件(第一轴承91、第二轴承92)。内侧轴承构件(第一轴承91、第二轴承92)将使行星齿轮(3)偏心摆动的偏心轴(7)保持为相对于内圈(61)能够旋转。在与旋转轴(Ax1)平行的方向上，多组滚动轴承(41、42)的至少一部分处于与内侧轴承构件(第一轴承91、第二轴承92)相同的位置。
根据该形态，能够抑制因设置滚动轴承(41、42)而引起的、与旋转轴(Ax1)平行的方向上的内啮合行星齿轮装置(1、1A)的尺寸的增大。
在第三形态的内啮合行星齿轮装置(1、1A)中，在第二形态的基础上，在与旋转轴(Ax1)平行的方向上，多组滚动轴承(41、42)的至少一部分处于与轴承构件(6、6A)相同的位置。
根据该形态，能够抑制因设置滚动轴承(41、42)而引起的、与旋转轴(Ax1)平行的方向上的内啮合行星齿轮装置(1、1A)的尺寸的增大。
在第四形态的内啮合行星齿轮装置(1、1A)中，在第一～第三任一形态的基础上，在多个内销(4)相对于内齿齿轮(2)为非旋转时，通过多个内销孔(32)各自的内周面(321)向多个内销(4)的各个内销靠压，由此对多个内销(4)的各个内销作用有预压力。
根据该形态，能够减少或消除至少因内销孔(32)的内周面(321)与 内销(4)之间的间隙而产生的齿隙，从而能够将角度传递误差抑制得小。而且，尽管使预压力作用于内销(4)，但在内销(4)自转之际也不易产生因摩擦阻力而引起的损失。
在第五形态的内啮合行星齿轮装置(1、1A)中，在第四形态的基础上，通过产生于多个内销(4)的各个内销的弯曲力矩来作用有预压力。
根据该形态，除内销(4)以外，无需设置用于产生预压力的其他部件就能够将部件个数抑制得少，因此，结果是有助于内啮合行星齿轮装置(1、1A)的小型化。
在第六形态的内啮合行星齿轮装置(1、1A)中，在第一～第五任一形态的基础上，多组滚动轴承(41、42)各自具有多个滚动体(402)。通过多个滚动体(402)向多个内销(4)的各个内销靠压，由此对多个内销(4)的各个内销作用有内销侧预压力。
根据该结构，能够减少或消除因内销(4)与滚动轴承(41、42)的间隙而产生的齿隙，从而能够将角度传递误差抑制得小。
在第七形态的内啮合行星齿轮装置(1、1A)中，在第一～第六任一形态的基础上，从与旋转轴(Ax1)平行的方向观察，多组滚动轴承(41、42)在绕着旋转轴(Ax1)的圆周方向上等间隔地配置。
根据该形态，利用多组滚动轴承(41、42)保持多个内销(4)，且在内啮合行星齿轮装置(1、1A)驱动时，能够将施加于多个内销(4)的力均等地分散。
在第八形态的内啮合行星齿轮装置(1、1A)中，在第一～第七任一形态的基础上，从与旋转轴(Ax1)平行的方向观察，穿过多组滚动轴承(41、42)的中心的虚拟圆(VC1)的中心与旋转轴(Ax1)一致。
根据该形态，有不易产生因定芯不佳而引起的振动的产生及传递效率的下降等的不良状况这样的优点。
第九形态的机器人用关节装置(200)包括：第一～第八任一形态的内 啮合行星齿轮装置(1、1A)；由外圈(62)固定的第一构件(201)；和由内圈(61)固定的第二构件(202)。
根据该形态，能够将内销孔(32)的直径抑制得比较小，因此能够进行行星齿轮(3)的小型化，且作为机器人用关节装置(200)整体也容易实现小型化。
关于第二～第八形态的结构，对于内啮合行星齿轮装置(1、1A)而言不是必需设置的结构，可以适当省略。
附图标记说明
1、1A 内啮合行星齿轮装置
2 内齿齿轮
3 行星齿轮
4 内销
6、6A 轴承构件
7 偏心轴
21 内齿
31 外齿
32 内销孔
41、42 滚动轴承
61 内圈
62 外圈
91 第一轴承(内侧轴承构件)
92 第二轴承(内侧轴承构件)
200 机器人用关节装置
201 第一构件
202 第二构件
321 内周面
402 滚动体
410、420 保持部
601A (第一)轴承构件
602A (第二)轴承构件
Ax1 旋转轴
VC1 虚拟圆
工业实用性
根据本公开实施例，能够提供容易小型化的内啮合行星齿轮装置及机器人用关节装置。

Claims (9)

  1. 一种内啮合行星齿轮装置，其中，包括：
    轴承构件，具有外圈及配置于所述外圈的内侧的内圈，将所述内圈支承为能够相对于所述外圈以旋转轴为中心相对旋转；
    内齿齿轮，具有内齿且固定于所述外圈；
    行星齿轮，具有与所述内齿局部性啮合的外齿；
    多个内销，在分别插入到在所述行星齿轮形成的多个内销孔中的状态下，一边在所述内销孔内公转一边相对于所述内齿齿轮相对旋转；和
    多组滚动轴承，相对于所述行星齿轮在与所述旋转轴平行的方向的两侧处保持所述多个内销的各个内销，
    所述多个内销的各个内销以能够自转的状态而保持于各组滚动轴承。
  2. 根据权利要求1所述的内啮合行星齿轮装置，其中，
    所述内啮合行星齿轮装置还包括内侧轴承构件，所述内侧轴承构件将使所述行星齿轮偏心摆动的偏心轴保持为相对于所述内圈能够旋转，
    在与所述旋转轴平行的方向上，所述多组滚动轴承的至少一部分处于与所述内侧轴承构件相同的位置。
  3. 根据权利要求1或2所述的内啮合行星齿轮装置，其中，
    在与所述旋转轴平行的方向上，所述多组滚动轴承的至少一部分处于与所述轴承构件相同的位置。
  4. 根据权利要求1～3中任一项所述的内啮合行星齿轮装置，其中，在所述多个内销相对于所述内齿齿轮为非旋转时，通过所述多个内销孔各自的内周面向多个内销的各个内销靠压，由此对所述多个内销的各个内销作用有预压力。
  5. 根据权利要求4所述的内啮合行星齿轮装置，其中，
    通过产生于所述多个内销的各个内销的弯曲力矩来作用有所述预压力。
  6. 根据权利要求1～5中任一项所述的内啮合行星齿轮装置，其中，
    所述多组滚动轴承各自具有多个滚动体，
    通过所述多个滚动体向所述多个内销的各个内销靠压，由此对所述多个内销的各个内销作用有内销侧预压力。
  7. 根据权利要求1～6中任一项所述的内啮合行星齿轮装置，其中，
    从与所述旋转轴平行的方向观察，所述多组滚动轴承在绕着所述旋转轴的圆周方向上等间隔地配置。
  8. 根据权利要求1～7中任一项所述的内啮合行星齿轮装置，其中，
    从与所述旋转轴平行的方向观察，穿过所述多组滚动轴承的中心的虚拟圆的中心与所述旋转轴一致。
  9. 一种机器人用关节装置，其中，包括：
    权利要求1～8中任一项所述的内啮合行星齿轮装置；和
    固定于所述外圈的第一构件；和
    固定于所述内圈的第二构件。
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