US20190203825A1 - Actuator - Google Patents
Actuator Download PDFInfo
- Publication number
- US20190203825A1 US20190203825A1 US16/303,234 US201716303234A US2019203825A1 US 20190203825 A1 US20190203825 A1 US 20190203825A1 US 201716303234 A US201716303234 A US 201716303234A US 2019203825 A1 US2019203825 A1 US 2019203825A1
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- US
- United States
- Prior art keywords
- tube portion
- gap
- axial direction
- rotor
- radial direction
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
- H02K7/10—Structural association with clutches, brakes, gears, pulleys or mechanical starters
- H02K7/116—Structural association with clutches, brakes, gears, pulleys or mechanical starters with gears
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- 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
- F16H57/042—Guidance of lubricant
- F16H57/0427—Guidance of lubricant on rotary parts, e.g. using baffles for collecting lubricant by centrifugal force
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- 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
- B25J9/12—Programme-controlled manipulators characterised by positioning means for manipulator elements electric
- B25J9/126—Rotary actuators
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- 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
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/0409—Features relating to lubrication or cooling or heating characterised by the problem to increase efficiency, e.g. by reducing splash losses
-
- 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
- F16H57/045—Lubricant storage reservoirs, e.g. reservoirs in addition to a gear sump for collecting lubricant in the upper part of a gear case
- F16H57/0454—Sealings between different partitions of a gearing or to a reservoir
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- 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
- F16H57/08—General details of gearing of gearings with members having orbital motion
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
- H02K7/08—Structural association with bearings
- H02K7/083—Structural association with bearings radially supporting the rotary shaft at both ends of the rotor
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
- H02K7/14—Structural association with mechanical loads, e.g. with hand-held machine tools or fans
-
- 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
- F16H49/00—Other gearings
- F16H49/001—Wave gearings, e.g. harmonic drive transmissions
-
- 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
- F16H57/02—Gearboxes; Mounting gearing therein
- F16H57/029—Gearboxes; Mounting gearing therein characterised by means for sealing the gearboxes, e.g. to improve airtightness
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
- H02K11/20—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for measuring, monitoring, testing, protecting or switching
- H02K11/21—Devices for sensing speed or position, or actuated thereby
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K2211/00—Specific aspects not provided for in the other groups of this subclass relating to measuring or protective devices or electric components
- H02K2211/03—Machines characterised by circuit boards, e.g. pcb
Definitions
- the present disclosure relates to an actuator.
- an articulated industrial robot In general, an articulated industrial robot is known.
- an actuator is provided at a joint between a first arm and a second arm, in order to relatively rotatably connect the first arm and the second arm.
- Japanese Unexamined Patent Application Publication No. 2001-304382 discloses a hollow actuator having a lubricant leakage prevention mechanism which prevents lubricant leakage from a hollow wave gear device to a hollow AC servomotor, or to the outside.
- a gap between a hollow output shaft and a wave generator is covered with a lubricant separation member, and an opening of the gap extends to a position close to a wave bearing of the wave generator in order to suppress the lubricant leakage.
- the lubricant leakage prevention mechanism has a complicated structure, and thus the number of components in the hollow actuator also increases. Consequently, it is difficult to reduce or prevent increases in manufacturing cost, and also it is difficult to sufficiently improve production efficiency.
- An actuator each include a motor including a first rotor rotatable in a circumferential direction about a center axis extending in a vertical direction, and a stator to drive the first rotor; a second rotor rotatable in the circumferential direction about the center axis; and a speed reducer which reduces rotation of the first rotor and transmits a torque to the second rotor, via a bearing, in which the first rotor includes a first tube portion extending in an axial direction, the second rotor includes a second tube portion extending in the axial direction, the second tube portion is provided radially outward of the first tube portion, a lubricant is filled in a filling space including at least a portion of a space between an outer surface of the first tube portion and an inner surface of the second tube portion, and the actuator further includes with a width reducing portion which reduces a width of the filling space in a radial direction in at least a
- FIG. 1 is a perspective view illustrating an exemplified configuration of an articulated robot.
- FIG. 2 is a cross-sectional view illustrating an exemplified configuration of an actuator.
- FIG. 3 is a cross-sectional view illustrating a first exemplified configuration of a width reducing portion.
- FIG. 4 is a cross-sectional view illustrating a flow of a lubricant in the first exemplified configuration.
- FIG. 5 is a cross-sectional view illustrating a modification example of the first exemplified configuration of the width reducing portion.
- FIG. 6 is a cross-sectional view illustrating another modification example of the first exemplified configuration of the width reducing portion.
- FIG. 7 is a cross-sectional view illustrating another example of an inclined portion and an inclined surface.
- FIG. 8 is a cross-sectional view illustrating a second exemplified configuration of the width reducing portion.
- FIG. 9 is a cross-sectional view illustrating a third exemplified configuration of the width reducing portion.
- a direction parallel to a center axis CA in an actuator 100 of an articulated robot R is referred to as the “axial direction”. Furthermore, in the axial direction, a direction from a cover 23 of a motor 110 toward a drive output portion 141 of a second rotor 140 is referred to as “upward”, while a direction from the drive output portion 141 of the second rotor 140 toward the cover 23 of the motor 110 is referred to as “downward”. Moreover, among surfaces of each component, a surface facing upward in the axial direction is referred to as “upper surface”, and a surface facing downward in the axial direction is referred to as “lower surface”.
- a direction perpendicular to the center axis CA is referred to as “radial direction” and a circumferential direction about the center axis CA is referred to as “circumferential direction”.
- a direction toward the center axis CA is referred to as “inward”
- a direction away from the center axis CA is referred to as “outward”.
- a side surface facing inward in the radial direction is referred to as “inner surface”
- a side surface facing outward in the radial direction is referred to as “outer surface”.
- FIG. 1 is a perspective view illustrating an exemplified configuration of the articulated robot R.
- the articulated robot R is, for example, an industrial robot used in a manufacturing system for semiconductor devices.
- the articulated robot R includes a first arm R 1 , a second arm R 2 , a joint shaft R 3 , a base R 4 , and actuators 100 a to 100 c , as shown in FIG. 1 .
- the articulated robot R is provided with working units such as a gripping device or an imaging device for assembly, transportation, etc., however, those are not shown in FIG. 1 .
- the actuator 100 a is provided at one end of the first arm R 1 .
- a working unit (not shown) is also attached to the actuator 100 a . That is, the actuator 100 a is provided at a first joint portion between the working unit and the one end of the first arm R 1 .
- the actuator 100 b is provided at a second joint portion between the other end of the first arm R 1 and one end of the second arm R 2 .
- the actuator 100 c is provided at a third joint portion between the other end of the second arm R 2 and one end of the joint shaft R 3 .
- one end fixed to the actuator 100 b is bent perpendicular to the other end fixed to the actuator 100 c .
- the other end of the joint shaft R 3 is fixed to the base R 4 for installing the articulated robot R.
- the first arm R 1 , the second arm R 2 and the working unit rotate relative to the joint shaft R 3 and the base R 4 by driving respective actuators 100 a , 100 b and 100 c . That is, the working unit rotates about a rotation axis of the actuator 100 a with respect to the first arm R 1 by driving the actuator 100 a at the first joint portion.
- the first arm R 1 , the actuator 100 a and the working unit rotate about a rotation axis of the actuator 100 b with respect to the second arm R 2 by driving the actuator 100 b at the second joint portion.
- first arm R 1 , the second arm R 2 , the actuators 100 a and 100 b , and the working unit rotate about a rotation axis of the actuator 100 c with respect to the joint shaft R 3 by driving the actuator 100 c at the third joint portion.
- the actuators 100 a , 100 b and 100 c of the respective joint portions will be collectively referred to as the actuator 100 hereinbelow.
- the center axis CA (refer to FIG. 2 described later) of the actuator 100 corresponds to the rotational axes of the actuators 100 a , 100 b and 100 c .
- the actuator 100 is provided at the first to third joint portions of the articulated robot R, however, the application of the actuator 100 is not limited to this example.
- FIG. 2 is a cross-sectional view illustrating an exemplified configuration of the actuator 100 .
- the actuator 100 is cut with a cutting plane including the center axis CA.
- the actuator 100 is provided with a motor 110 , a speed reducer 120 , a cross-roller bearing 130 , a second rotor 140 , and a second bearing 150 , as shown in FIG. 2 .
- the motor 110 includes a first rotor 1 , a stationary portion 2 , a first bearing 3 , a lubricant 4 , and a width reducing portion 5 .
- the motor 110 further includes a stator 21 (described below) for driving the first rotor 1 .
- the motor 110 is an outer rotor type, and is a driving source of the actuator 100 .
- the first rotor 1 is rotatable in the circumferential direction about the center axis CA extending in the vertical direction.
- the first rotor 1 includes a tubular first tube portion 11 , a circular plate portion 12 having an annular shape, a tubular magnet holding member 13 , and a rotor magnet 14 .
- the first tube portion 11 extends in the axial direction to face a post portion 201 of a shaft 20 (described later) in the radial direction.
- the first tube portion 11 has a protrusion portion 11 a .
- the protrusion portion 11 a is provided at a connecting part between the first tube portion 11 and the circular plate portion 12 .
- the protrusion portion 11 a is, for example, a step that protrudes from the circular plate portion 12 .
- the circular plate portion 12 extends outward in the radial direction from a lower portion of the first tube portion 11 in the axial direction.
- the magnet holding member 13 extends downward in the axial direction from an outer peripheral portion of the circular plate portion 12 in the radial direction, thereby holding the rotor magnet 14 .
- the rotor magnet 14 is held on an inner surface of the magnet holding member 13 , faces the stator 21 in the radial direction, and is rotatable together with the first rotor 1 in the circumferential direction.
- the rotor magnet 14 is disposed facing an outer surface of the stator 21 in the radial direction.
- a plurality of different magnetic poles are alternately arranged on the inner surface of the magnet holding member 13 in the circumferential direction.
- the stationary portion 2 rotatably supports the second rotor 140 via the cross-roller bearing 130 and the second bearing 150 .
- the stationary portion 2 includes a shaft 20 , a stator 21 , a bracket 22 , a cover 23 , a substrate 24 , a cable 25 , a sensor 26 , and flexible printed circuits (FPC) 27 .
- FPC flexible printed circuits
- the shaft 20 is a fixed shaft.
- the shaft 20 includes a through-hole 20 a penetrating in the axial direction.
- the through-hole 20 a is a space that penetrates the post portion 201 , as well as a disk portion 2021 and a tube portion 2022 of a lid portion 202 , as described below.
- the shaft 20 includes the post portion 201 extending along the center axis CA and the lid portion 202 provided at one end (upper end) of the post portion 201 in the axial direction.
- the post portion 201 is a cylindrical hollow member penetrated by the through-hole 20 a .
- the post portion 201 and the lid portion 202 may be different members provided separately from each other as shown in FIG. 2 , but may be coupled to each other to form a single member.
- the lid portion 202 includes the disk portion 2021 and the tube portion 2022 .
- the disk portion 2021 extends radially outward from the post portion 201 when viewed from the axial direction.
- the tube portion 2022 extends downward in the axial direction from an inner peripheral portion of the disk portion 2021 in the radial direction.
- the tube portion 2022 extends from the disk portion 2021 toward the post portion 201 in the axial direction, and is coupled to one end of the post portion 201 in the axial direction.
- the inner diameter of a lower portion of the tube portion 2022 in the axial direction is slightly larger than the outer diameter of an upper portion of the post portion 201 in the axial direction. Therefore, the tube portion 2022 is coupled to the upper portion of the post portion 201 in the axial direction by fitting the upper portion of the post portion 201 in the axial direction into the lower portion of the tube portion 2022 in the axial direction.
- the stator 21 faces the magnet holding member 13 of the first rotor 1 in the radial direction to drive the first rotor 1 .
- the bracket 22 is a member accommodating the stator 21 therein and holding the stator 21 .
- the bracket 22 includes a wall portion 221 as shown in FIG. 2 .
- the motor 110 includes the wall portion 221 , and the wall portion 221 faces, radially outward of the magnet holding member 13 , the magnet holding member 13 in the radial direction.
- the cover 23 accommodates the stator 21 and a lower portion of the substrate 24 in the axial direction, and is attached to the bracket 22 .
- the covers 23 are, for example, fixed to the first arm R 1 , the second arm R 2 and the joint shaft R 3 , at the first to third joint portions of the articulated robot R (see FIG. 1 ), respectively.
- the cover 23 of the actuator 100 a is fixed to one end of the first arm R 1 .
- the cover 23 of the actuator 100 b is fixed to one end of the second arm R 2 .
- the cover 23 of the actuator 100 c is fixed to one end of the joint shaft R 3 .
- the substrate 24 is attached to a lower surface of the bracket 22 at a lower end of the motor 110 in the axial direction.
- the substrate 24 is provided on a side opposite to the sensor 26 with the post portion 201 interposed therebetween in the axial direction.
- the substrate 24 is electrically connected to the stator 21 , and further electrically connected to the sensor 26 via a cable 25 and an FPC 27 .
- the substrate 24 carries a control circuit (not shown), a communication circuit (not shown), and the like.
- the control circuit has functions of performing drive control of the motor 110 , and controlling a rotational position of the second rotor 140 .
- the communication circuit contains an input/output terminal complying with, for example, the Ethernet standard, and has a function of communicating with a device outside the actuator 100 . Therefore, it is possible to control the actuator 100 using an external device connected to the communication circuit.
- the cable 25 is a wiring passing inside the through-hole 20 a , and electrically connects the sensor 26 and the substrate 24 . Consequently, the sensor 26 for detecting a rotational position of a sensor magnet 146 (described later) is connected to the substrate 24 via the cable 25 communicating inside of the through-hole 20 a in the axial direction, which penetrates the shaft 20 and the post portion 201 in the axial direction. Accordingly, the cable 25 , which electrically connects the sensor 26 and the substrate 24 , does not have to pass through, for example, outside of the stationary portion 2 , radially outward of the shaft 20 in the radial direction. Therefore, the actuator 100 can be downsized in the radial direction.
- the sensor 26 is, for example, a Hall element, which is provided on the lid portion 202 .
- the sensor 26 faces a portion of a trajectory of the sensor magnet 146 rotating in the circumferential direction to detect a rotational position of the sensor magnet 146 .
- the sensor 26 may be at a position in the axial direction facing a portion of the trajectory of the sensor magnet 146 rotating in the circumferential direction, or at a position in the radial direction facing a portion of the trajectory of the sensor magnet 146 rotating in the circumferential direction, as shown in FIG. 2 .
- the FPC 27 is a bendable printed circuit board on which the sensor 26 is mounted, and is affixed to the lower surface of the disk portion 2021 .
- the first bearing 3 is provided between the first rotor 1 and the shaft 20 of the stationary portion 2 .
- the first bearing 3 is provided between the first tube portion 11 and the post portion 201 .
- the first bearing 3 rotatably supports the first rotor 1 with respect to the stationary portion 2 .
- a ball bearing can be used as the first bearing 3 .
- the first bearing 3 is fixed to the first rotor 1 , and to the post portion 201 of the shaft 20 provided in the stationary portion 2 , as shown in FIG. 2 .
- an inner ring of the first bearing 3 is fixed to an outer surface of the post portion 201 .
- an outer ring of the first bearing 3 is fixed to an inner surface of the first tube portion 11 of the first rotor 1 .
- the first bearing 3 is disposed above a magnetic circuit of the motor 110 in the axial direction, which includes the rotor magnet 14 , the stator 21 , etc., and does not overlap with the magnetic circuit in the radial direction. Therefore, it is possible to downsize the actuator 100 by increasing a size in the radial direction of the magnetic circuit of the motor 110 , or decreasing a size in the radial direction of the actuator 100 , as compared with a case where the first bearing 3 overlaps with the magnetic circuit in the radial direction.
- the lubricant 4 is, for example, grease, and is filled in a filling space S including at least a portion of a space between an outer surface of the first tube portion 11 and an inner surface of a second tube portion 143 .
- the width reducing portion 5 reduces a width of the filling space S in the radial direction in at least a portion of the filling space S in the axial direction. Consequently, a flow of the lubricant 4 leaking from the filling space S to the outside is suppressed by the width reducing portion 5 . Accordingly, it is possible to reduce the lubricant 4 leaking from the filling space S to the outside. Therefore, it is possible to suppress leakage of the lubricant 4 with a simple configuration.
- the width reducing portion 5 includes at least one of a sealing member 51 and a gap member 52 .
- the sealing member 51 is in the shape of a plate extending in the radial direction and annular when viewed from the axial direction. In FIG. 2 , the sealing member 51 forms a first gap S 1 with the first tube portion 11 .
- the gap member 52 is annular when viewed from the axial direction.
- the gap member 52 forms a second gap S 2 with the second tube portion 143 in FIG. 2 . In particular, the gap member 52 forms the second gap S 2 with a hat gear 122 .
- a configuration of the width reducing portion 5 will be described later.
- the speed reducer 120 reduces the rotation of the first rotor 1 and transmits the torque to the second rotor 140 via an elastic bearing 124 .
- Flexwave registered trademark, manufactured by Nidec-Shimpo Corporation
- Nidec-Shimpo Corporation which is a wave gear device having a reduction ratio of 1/100
- Other reducer such as a planetary gear device may be used as the speed reducer 120 of the actuator 100 .
- the speed reducer 120 includes an internal gear 121 , a hat gear 122 , a cam 123 , and an elastic bearing 124 , as shown in FIG. 2 .
- the internal gear 121 is an internal gear having rigidity, in which teeth aligned in the circumferential direction are formed on an inner surface in the radial direction.
- the internal gear 121 is connected to an inner ring of the cross-roller bearing 130 and a drive output portion 141 (described later) of the second rotor 140 , and is rotatable together with those components in the circumferential direction.
- the hat gear 122 includes a cylindrical portion extending in the axial direction, and an annular portion covering an upper end of the cylindrical portion in the axial direction.
- the post portion 201 of the shaft 20 is inserted into an opening provided at the center of the annular portion.
- the cylindrical portion of the hat gear 122 is deformable in the radial direction.
- An outer surface of the cylindrical portion in the radial direction has teeth formed in the circumferential direction. The number of the teeth is smaller than the number of the teeth formed on an inner surface of the internal gear 121 .
- the cam 123 has an elliptical shape when viewed from the axial direction, and is fixed to the first rotor 1 so as to be rotatable together with the first rotor 1 .
- the cam 123 is formed with an opening penetrating in the axial direction at its center.
- the cam 123 is rotatable about the center axis CA with respect to the post portion 201 by inserting the post portion 201 of the shaft 20 into the opening of the cam 123 .
- the elastic bearing 124 is a radially deformable bearing, and is provided on an outer surface of the cam 123 along an outer peripheral portion of the elliptical cam 123 .
- the elastic bearing 124 is held by the first rotor 1 radially outward of the first bearing 3 , and rotatably supports the second rotor 140 .
- An inner ring of the elastic bearing 124 is fixed to the cam 123 , is attached to the first rotor 1 via the cam 123 , and is rotatable together with the first rotor 1 in the circumferential direction.
- the elastic bearing 124 is accommodated inside the cylindrical portion of the hat gear 122 , and deforms the cylindrical portion of the hat gear 122 in the radial direction in response to a shape of the cam 123 .
- the elastic bearing 124 deflects the cylindrical portion of the hat gear 122 by pushing the cylindrical portion in the radial direction, so that the teeth formed on an outer surface of the deflected portion are partially engaged with the teeth formed on the inner surface of the internal gear 121 .
- the elastic bearing 124 moves a position at which the hat gear 122 and the internal gear 121 are partially engaged in the circumferential direction by rotating the elastic bearing 124 together with the first rotor 1 .
- the internal gear 121 having more teeth than the hat gear 122 rotates at a lower speed than that of the hat gear 122 in response to a difference between the number of teeth of hat gear 122 and the number of teeth of the internal gear 121 . Accordingly, the speed reducer 120 rotates the second rotor 140 connected to the internal gear 121 at a lower speed than that of the first rotor 1 inputting the driving force of the elastic bearing 124 and the hat gear 122 .
- the second rotor 140 is rotatable about the center axis CA in the circumferential direction.
- the second rotor 140 includes a drive output portion 141 , a rotation transmission portion 142 , a tubular second tube portion 143 , a rotor support portion 144 , a magnet support portion 145 , and a sensor magnet 146 .
- the drive output portions 141 are connected to the working unit, the first arm R 1 and the second arm R 2 , at the first to third joint portions of the articulated robot R (see FIG. 1 ), respectively.
- the drive output portions 141 output the driving force of the actuator 100 to the working unit, the first arm R 1 and the second arm R 2 .
- the drive output portion 141 of the actuator 100 a is connected to the working unit and outputs the driving force to the working unit.
- the drive output portion 141 of the actuator 100 b is connected to the first arm R 1 and outputs the driving force to the first arm R 1 .
- the drive output portion 141 of the actuator 100 c is connected to the second arm R 2 and outputs the driving force to the second arm R 2 .
- the rotation transmission portion 142 is connected to the drive output portion 141 and the second tube portion 143 , and is rotatable together with the drive output portion 141 and the second tube portion 143 in the circumferential direction.
- the rotation transmission portion 142 transmits the driving force, input from the first rotor 1 and reduced in the rotation speed by the speed reducer 120 , to the second rotor 140 (in particular, the drive output portion 141 ).
- the rotation transmission portion 142 is the same member as the internal gear 121 of the speed reducer 120 in this embodiment. That is, the internal gear 121 functions as the rotation transmission portion 142 .
- the rotation transmission portion 142 is not limited to this example, and may be a different member from the internal gear 121 . In a case where the rotation transmission portion 142 is a different member, the rotation transmission portion 142 is connected to the internal gear 121 .
- the second tube portion 143 extends in the axial direction, and is provided radially outward of the first tube portion 11 .
- the second tube portion 143 is connected to the rotation transmission portion 142 .
- the second tube portion 143 is the same member as the inner ring of the cross-roller bearing 130 in this embodiment. That is, the inner ring of the cross-roller bearing 130 functions as the second tube portion 143 .
- the second tube portion 143 is not limited to this example, and may be a different member from the inner ring of the cross-roller bearing 130 . In a case where the second tube portion 143 is a different member, the second tube portion 143 is connected to the inner ring of the cross-roller bearing 130 .
- the rotor support portion 144 positions an attachment position of the second bearing 150 to the drive output portion 141 .
- the magnet support portion 145 supports the sensor magnet 146 .
- the sensor magnet 146 is provided on the second rotor 140 and is rotatable together with the second rotor 140 in the circumferential direction.
- the sensor magnet 146 is provided with different magnetic poles formed alternately in the circumferential direction, and is disposed facing the sensor 26 in the radial direction.
- the sensor magnet 146 is not limited to the example of this embodiment, and may be configured to have a plurality of magnet pieces having different magnetic poles alternately arranged in the circumferential direction.
- a configuration of the width reducing portion 5 will be described with reference to first to third exemplified configurations.
- FIG. 3 is a cross-sectional view illustrating the first exemplified configuration of the width reducing portion 5 .
- FIG. 3 corresponds to a part surrounded by a broken line in FIG. 2 .
- the width reducing portion 5 includes the sealing member 51 and the gap member 52 as shown in FIG. 3 .
- the sealing member 51 is provided at an upper end of the wall portion 221 of the bracket 22 in the axial direction, and extends radially inward from the upper end of the wall portion 221 .
- an outer end of the sealing member 51 in the radial direction is provided on the wall portion 211 ; in particular, the outer end of the sealing member 51 is fixed to an upper surface of the wall portion 211 .
- An inner end of the sealing member 51 in the radial direction faces the first tube portion 11 , and forms a minute first gap S 1 with the outer surface of the first tube portion 11 in the radial direction.
- a gap between the sealing member 51 and the first tube portion 11 in the axial direction (that is, the shortest distance therebetween, and a width W of the first gap S 1 in the radial direction) is, for example, 0.05 mm. It is possible to suppress a flow of the lubricant 4 leaking from the filling space S to the outside by providing the sealing member 51 in the filling space S. Even though the sealing member 51 is provided in the filling space S, the volume of the filling space S is not reduced so much. Therefore, leakage of the lubricant 4 can be suppressed without significantly reducing a filling amount of the lubricant 4 in the filling space S.
- the gap member 52 is provided on the first tube portion in FIG. 3 .
- a position of the gap member 52 in the axial direction is determined by the protrusion portion 11 a .
- the protrusion portion 11 a is coupled with the first tube portion 11 in FIG. 3 , but is not limited to this example.
- the protrusion portion 11 a may not be coupled with the first tube portion 11 . That is, the protrusion portion 11 a may protrude axially upward from the circular plate portion 12 at a position away from the first tube portion 11 in the radial direction.
- the gap member 52 includes an inclined portion 521 upward in the axial direction.
- the inclined portion 521 of the gap member 52 includes, axially upward, an inclined surface 521 a intersecting the axial direction.
- an outer peripheral edge of the inclined surface 521 a on a side of the second tube portion 143 is disposed axially upward of an inner peripheral edge of the inclined surface 521 a on a side of the first tube portion 11 .
- an upper portion of the gap member 52 in the axial direction is the inclined portion 521
- an upper surface of the gap member 52 toward the elastic bearing 124 is the inclined surface 521 a . Consequently, the gap member 52 having the inclined surface 521 a can be easily manufactured.
- a shape of the gap member 52 is simple, thus a strength of the gap member 52 can be enhanced as compared with a case where such a shape is complicated.
- FIG. 4 is a cross-sectional view illustrating a flow of the lubricant 4 in the first exemplified configuration.
- the sealing member 51 forms the first gap S 1
- the gap member 52 forms the second gap S 2 .
- the sealing member 51 is provided between the gap member 52 and the circular plate portion 12 of the first rotor 1 in the axial direction. Consequently, a labyrinth structure space can be formed in the filling space S filled with the lubricant 4 .
- the lubricant 4 flows through the labyrinth structure space when flowing from the filling space S to the outside.
- the lubricant 4 needs to pass through the second gap S 2 formed by the annular gap member 52 , a space between the annular sealing member 51 and the annular gap member 52 , the first gap S 1 between the inner end of the annular sealing member 51 in the radial direction and the first tube portion 11 , and a space between the annular sealing member 51 and the circular plate portion 12 having the annular shape. Accordingly, the lubricant 4 hardly flows from the filling space S to the outside. Therefore, it is possible to further suppress leakage of the lubricant 4 .
- the outer end of the sealing member 51 in the radial direction is not limited to the examples of FIGS. 3 and 4 , and may be provided at a lower end of the hat gear 122 provided in the speed reducer in the axial direction. That is, in a case where the width reducing portion 5 includes at least the sealing member 51 , the outer end of the sealing member 51 in the radial direction may be provided on the speed reducer 120 .
- FIG. 5 is a cross-sectional view illustrating a modification example of the first exemplified configuration of the width reducing portion 5 .
- FIG. 5 corresponds to a part surrounded by a broken line in FIG. 2 .
- the gap member 52 provided on the second tube portion 143 forms a third gap S 3 with the first tube portion 11 as shown in FIG. 5 .
- the inner peripheral edge of the inclined surface 521 a of the inclined portion 521 on a side of the first tube portion 11 is axially upward of the outer peripheral edge of the inclined surface 521 a on a side of the second tube portion 143 , as shown in FIG. 5 .
- the gap member 52 may be provided on one member of the first tube portion 11 and the second tube portion 143 .
- the gap member 52 forms the second gap S 2 or the third gap S 3 with the other member of the first tube portion 11 and the second tube portion 143 in the radial direction.
- a protrusion portion 143 a may be provided on the second tube portion 143 to position the gap member 52 in the axial direction.
- the protrusion portion 143 a protrudes in the radial direction from the second tube portion 143 toward the first tube portion 11 .
- one member of the first tube portion 11 and the second tube portion 143 may include a protrusion portion 11 a or 143 a which protrudes toward the other member in the radial direction.
- the gap member 52 is in contact with the protrusion portion 11 a or 143 a in the axial direction. Consequently, a position of the gap member 52 in the axial direction is determined by the protrusion portion 11 a or 143 a .
- the lower end of the gap member 52 in the axial direction is in contact with an upper surface of the protrusion portion 11 a or 143 a , thus the gap member 52 is positioned in the axial direction by the protrusion portion 11 a or 143 a . Therefore, the gap member 52 can be attached more easily, and the attachment work can be carried out with the improved efficiency.
- the outer end of the sealing member 51 in the radial direction may be provided at a lower end of the second tube portion 143 in the axial direction. That is, in a case where the width reducing portion 5 includes at least the sealing member 51 , the outer end of the sealing member 51 in the radial direction may be provided on the second tube portion 143 .
- the speed reducer 120 may be, for example, a planetary speed reducer other than the wave gear device.
- the gap member 52 is a member different from one member of the first tube portion 11 and the second tube portion 143 in FIGS. 3 to 5 .
- the configuration of the gap member 52 is not limited to these examples.
- FIG. 6 is a cross-sectional view illustrating another modification example of the first exemplified configuration of the width reducing portion 5 .
- FIG. 6 corresponds to a part surrounded by a broken line in FIG. 2 .
- the gap member 52 may be integrally formed with one of the first tube portion 11 and the second tube portion 143 .
- the gap member 52 provided on the first tube portion 11 may form a single member with the first tube portion 11 , and in other words, may be a portion of the first tube portion 11 , as shown in FIG. 6 .
- the gap member 52 provided on the second tube portion 143 may form a single member with the second tube portion 143 , and in other words, may be a portion of the second tube portion 143 . Consequently, the number of components in the actuator 100 can be decreased, thus it is possible to suppress increase in manufacturing cost, and to sufficiently improve production efficiency.
- the gap member 52 may be made of the same material as that of one member of the first tube portion 11 and the second tube portion 143 , or a different material from that of the one member.
- a peripheral edge of the inclined surface 521 a of the inclined portion 521 in the radial direction on a side of one member of the first tube portion 11 and the second tube portion 143 is closer to a side of the elastic bearing 124 in the axial direction than a peripheral edge on a side of the other member.
- an inclination angle ⁇ of the inclined surface 521 a with respect to the axial direction from the gap member 52 toward the elastic bearing 124 is an acute angle. Consequently, the lubricant 4 hardly flows toward the second gap S 2 or the third gap S 3 by the inclined surface 521 a . Therefore, it is possible to further suppress leakage of the lubricant 4 .
- the entire upper surface of the gap member 52 in the axial direction is the inclined surface 521 a .
- the configuration of the inclined surface 521 a is not limited to these examples.
- the inclined portion 521 may be a portion of the upper portion of the gap member 52 in the axial direction.
- the inclined surface 521 a may be a portion of an upper surface of the inclined portion 521 .
- FIG. 7 is a cross-sectional view illustrating another example of the inclined portion 521 and the inclined surface 521 a .
- FIG. 7 corresponds to a part surrounded by a broken line in FIG. 2 .
- the inclined portion 521 may be a portion of the upper portion of the gap member 52 in the axial direction. Furthermore, the inclined portion 521 may protrude axially upward from the upper surface of the gap member 52 ; in particular, the inclined portion 521 may protrude axially upward from a partial region of the upper surface in the radial direction.
- the inclined portion 521 may extend in the circumferential direction, and is preferably annular. In this case, the inclined portion 521 overlaps with the upper surface of the gap member 52 when viewed from the axial direction.
- the upper surface is a surface of the gap member 52 toward the elastic bearing 124 . “Axially upward” means a side of the elastic bearing 124 in the axial direction.
- the volume of the filling space S reduced by the gap member 52 is smaller as compared with a case where the upper surface of the gap member 52 is the inclined surface 521 a . Additionally, the lubricant 4 hardly flows to the second gap S 2 by the inclined surface 521 a . Therefore, it is possible to further suppress leakage of the lubricant 4 while suppressing reduction of the amount of the lubricant 4 fillable in the filling space S.
- a position of the inclined portion 521 in the radial direction in the upper surface of the gap member 52 is radially outward of an inner surface of the gap member 52 .
- Such a position may also be radially inward of an outer surface of the gap member 52 , and preferably overlaps with the inner surface or the outer surface of the gap member 52 when viewed from the axial direction.
- the peripheral edge of the inclined surface 521 a preferably overlaps with a peripheral edge of the gap member 52 in, rather than a side of one member of the of the first tube portion 11 and the second tube portion 143 , a side of the other member in the radial direction, when viewed from the axial direction.
- the peripheral edge of the inclined surface 521 a preferably overlaps with an outer peripheral edge of the gap member 52 , radially outward, i.e., closer to a side of the second tube portion 143 than a side of the first tube portion 11 in the radial direction, when viewed from the axial direction.
- the peripheral edge of the inclined surface 521 a preferably overlaps with an inner peripheral edge of the gap member 52 , radially inward, i.e.
- the lubricant 4 further hardly flows toward the second gap S 2 or the third gap S 3 .
- the width reducing portion 5 includes both of the sealing member 51 and the gap member 52 in the first exemplified configuration.
- the width reducing portion 5 is not limited to the example of the first exemplified configuration, and may be configured to include one of the sealing member 51 and the gap member 52 without the other one.
- FIG. 8 is a cross-sectional view illustrating a second exemplified configuration of the width reducing portion 5 .
- FIG. 8 corresponds to a part surrounded by a broken line in FIG. 2 .
- the width reducing portion includes the sealing member 51 but does not include the gap member 52 , as shown in FIG. 8 . Additionally, the outer end of the sealing member 51 in the radial direction is provided on the wall portion 221 as shown in FIG. 8 .
- the outer end of the sealing member 51 in the radial direction is not limited to the example of FIG. 8 , and may be provided on one of the speed reducer 120 or the second tube portion 143 .
- the outer end of the sealing member 51 in the radial direction may be provided at the lower end of the hat gear 122 of the speed reducer 120 .
- the outer end of the sealing member 51 in the radial direction may be provided on a lower portion of the second tube portion 143 in the axial direction.
- the lubricant 4 needs to pass through, when flowing from the filling space S to the outside, the first gap S 1 between the inner end of the annular sealing member 51 in the radial direction and the first tube portion 11 , and a space between the annular sealing member 51 and the circular plate portion 12 having the annular shape. Accordingly, the lubricant 4 hardly flows from the filling space S to the outside as compared with a configuration where the sealing member 51 is not provided on the actuator 100 . Therefore, it is possible to suppress leakage of the lubricant 4 by the sealing member 51 .
- FIG. 9 is a cross-sectional view illustrating a third exemplified configuration of the width reducing portion 5 .
- FIG. 9 corresponds to a part surrounded by a broken line in FIG. 2 .
- the width reducing portion 5 includes at least the gap member 52 , as shown in FIG. 9 .
- the gap member 52 is provided on the first tube portion 11 and is in contact with the circular plate portion 12 .
- the gap member 52 forms the second gap S 2 with the second tube portion 143 in the radial direction.
- the gap member 52 forms the second gap S 2 with the cylindrical portion of the hat gear 122 extending in the axial direction. Consequently, it is possible to position the gap member 52 in the axial direction by the circular plate portion 12 of the first rotor 1 . Therefore, the gap member 52 can be attached more easily, and the attachment work can be carried out with the improved efficiency.
- the lubricant 4 needs to pass through, when flowing from the filling space S to the outside, the second gap S 2 formed by the annular gap member 52 . Accordingly, the lubricant 4 hardly flows from the filling space S to the outside as compared with a configuration where the width reducing portion 5 is not provided on the actuator 100 . Therefore, it is possible to suppress leakage of the lubricant 4 by the gap member 52 .
- the present disclosure is useful for an actuator attached to the robot or the like.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Power Engineering (AREA)
- Robotics (AREA)
- Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)
- General Details Of Gearings (AREA)
- Retarders (AREA)
Abstract
An actuator includes a motor including a first rotor rotatable in a circumferential direction, and a stator to drive the first rotor; a second rotor rotatable in the circumferential direction; and a speed reducer that reduces rotation of the first rotor and transmits a torque to the second rotor via a bearing. The first and second rotors include first and second tube portions extending in an axial direction, respectively. The second tube portion is radially outward of the first tube portion. A lubricant is filled in a filling space including at least a portion of a space between an outer surface of the first tube portion and an inner surface of the second tube portion. The actuator includes a width reducing portion that reduces a width of the filling space in a radial direction in at least a portion of the filling space in the axial direction.
Description
- The present disclosure relates to an actuator.
- In general, an articulated industrial robot is known. In such an industrial robot, an actuator is provided at a joint between a first arm and a second arm, in order to relatively rotatably connect the first arm and the second arm.
- For example, Japanese Unexamined Patent Application Publication No. 2001-304382 discloses a hollow actuator having a lubricant leakage prevention mechanism which prevents lubricant leakage from a hollow wave gear device to a hollow AC servomotor, or to the outside.
- In a lubricant leakage prevention mechanism, a gap between a hollow output shaft and a wave generator is covered with a lubricant separation member, and an opening of the gap extends to a position close to a wave bearing of the wave generator in order to suppress the lubricant leakage.
- However, in Japanese Unexamined Patent Application Publication No. 2001-304382, the lubricant leakage prevention mechanism has a complicated structure, and thus the number of components in the hollow actuator also increases. Consequently, it is difficult to reduce or prevent increases in manufacturing cost, and also it is difficult to sufficiently improve production efficiency.
- An actuator according to an exemplary embodiment of the present disclosure each include a motor including a first rotor rotatable in a circumferential direction about a center axis extending in a vertical direction, and a stator to drive the first rotor; a second rotor rotatable in the circumferential direction about the center axis; and a speed reducer which reduces rotation of the first rotor and transmits a torque to the second rotor, via a bearing, in which the first rotor includes a first tube portion extending in an axial direction, the second rotor includes a second tube portion extending in the axial direction, the second tube portion is provided radially outward of the first tube portion, a lubricant is filled in a filling space including at least a portion of a space between an outer surface of the first tube portion and an inner surface of the second tube portion, and the actuator further includes with a width reducing portion which reduces a width of the filling space in a radial direction in at least a portion of the filling space in the axial direction.
- The above and other elements, features, steps, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.
-
FIG. 1 is a perspective view illustrating an exemplified configuration of an articulated robot. -
FIG. 2 is a cross-sectional view illustrating an exemplified configuration of an actuator. -
FIG. 3 is a cross-sectional view illustrating a first exemplified configuration of a width reducing portion. -
FIG. 4 is a cross-sectional view illustrating a flow of a lubricant in the first exemplified configuration. -
FIG. 5 is a cross-sectional view illustrating a modification example of the first exemplified configuration of the width reducing portion. -
FIG. 6 is a cross-sectional view illustrating another modification example of the first exemplified configuration of the width reducing portion. -
FIG. 7 is a cross-sectional view illustrating another example of an inclined portion and an inclined surface. -
FIG. 8 is a cross-sectional view illustrating a second exemplified configuration of the width reducing portion. -
FIG. 9 is a cross-sectional view illustrating a third exemplified configuration of the width reducing portion. - Exemplified embodiments of the present disclosure will be described below with reference to the drawings.
- In this specification, a direction parallel to a center axis CA in an
actuator 100 of an articulated robot R is referred to as the “axial direction”. Furthermore, in the axial direction, a direction from acover 23 of amotor 110 toward adrive output portion 141 of asecond rotor 140 is referred to as “upward”, while a direction from thedrive output portion 141 of thesecond rotor 140 toward thecover 23 of themotor 110 is referred to as “downward”. Moreover, among surfaces of each component, a surface facing upward in the axial direction is referred to as “upper surface”, and a surface facing downward in the axial direction is referred to as “lower surface”. - A direction perpendicular to the center axis CA is referred to as “radial direction” and a circumferential direction about the center axis CA is referred to as “circumferential direction”. In the radial direction, a direction toward the center axis CA is referred to as “inward”, while a direction away from the center axis CA is referred to as “outward”. Moreover, among lateral surfaces of each component, a side surface facing inward in the radial direction is referred to as “inner surface”, and a side surface facing outward in the radial direction is referred to as “outer surface”.
- It should be noted that the directions and surfaces stated above do not indicate the positional relationships, directions, etc., when incorporated in the actual device.
-
FIG. 1 is a perspective view illustrating an exemplified configuration of the articulated robot R. The articulated robot R is, for example, an industrial robot used in a manufacturing system for semiconductor devices. The articulated robot R includes a first arm R1, a second arm R2, a joint shaft R3, a base R4, andactuators 100 a to 100 c, as shown inFIG. 1 . Additionally, the articulated robot R is provided with working units such as a gripping device or an imaging device for assembly, transportation, etc., however, those are not shown inFIG. 1 . - The
actuator 100 a is provided at one end of the first arm R1. A working unit (not shown) is also attached to theactuator 100 a. That is, theactuator 100 a is provided at a first joint portion between the working unit and the one end of the first arm R1. Theactuator 100 b is provided at a second joint portion between the other end of the first arm R1 and one end of the second arm R2. Theactuator 100 c is provided at a third joint portion between the other end of the second arm R2 and one end of the joint shaft R3. In the second arm R2, one end fixed to theactuator 100 b is bent perpendicular to the other end fixed to theactuator 100 c. The other end of the joint shaft R3 is fixed to the base R4 for installing the articulated robot R. - The first arm R1, the second arm R2 and the working unit rotate relative to the joint shaft R3 and the base R4 by driving
respective actuators actuator 100 a with respect to the first arm R1 by driving theactuator 100 a at the first joint portion. The first arm R1, theactuator 100 a and the working unit rotate about a rotation axis of theactuator 100 b with respect to the second arm R2 by driving theactuator 100 b at the second joint portion. Furthermore, the first arm R1, the second arm R2, theactuators actuator 100 c with respect to the joint shaft R3 by driving theactuator 100 c at the third joint portion. - The
actuators actuator 100 hereinbelow. In this case, the center axis CA (refer toFIG. 2 described later) of theactuator 100 corresponds to the rotational axes of theactuators actuator 100 is provided at the first to third joint portions of the articulated robot R, however, the application of theactuator 100 is not limited to this example. -
FIG. 2 is a cross-sectional view illustrating an exemplified configuration of theactuator 100. InFIG. 2 , theactuator 100 is cut with a cutting plane including the center axis CA. Theactuator 100 is provided with amotor 110, aspeed reducer 120, a cross-roller bearing 130, asecond rotor 140, and a second bearing 150, as shown inFIG. 2 . - First, a configuration of the
motor 110 will be described. Themotor 110 includes afirst rotor 1, astationary portion 2, a first bearing 3, alubricant 4, and awidth reducing portion 5. Themotor 110 further includes a stator 21 (described below) for driving thefirst rotor 1. Themotor 110 is an outer rotor type, and is a driving source of theactuator 100. - The
first rotor 1 is rotatable in the circumferential direction about the center axis CA extending in the vertical direction. Thefirst rotor 1 includes a tubularfirst tube portion 11, acircular plate portion 12 having an annular shape, a tubularmagnet holding member 13, and arotor magnet 14. Thefirst tube portion 11 extends in the axial direction to face apost portion 201 of a shaft 20 (described later) in the radial direction. Moreover, thefirst tube portion 11 has aprotrusion portion 11 a. Theprotrusion portion 11 a is provided at a connecting part between thefirst tube portion 11 and thecircular plate portion 12. Theprotrusion portion 11 a is, for example, a step that protrudes from thecircular plate portion 12. Thecircular plate portion 12 extends outward in the radial direction from a lower portion of thefirst tube portion 11 in the axial direction. Themagnet holding member 13 extends downward in the axial direction from an outer peripheral portion of thecircular plate portion 12 in the radial direction, thereby holding therotor magnet 14. Therotor magnet 14 is held on an inner surface of themagnet holding member 13, faces thestator 21 in the radial direction, and is rotatable together with thefirst rotor 1 in the circumferential direction. Therotor magnet 14 is disposed facing an outer surface of thestator 21 in the radial direction. In particular, a plurality of different magnetic poles are alternately arranged on the inner surface of themagnet holding member 13 in the circumferential direction. - The
stationary portion 2 rotatably supports thesecond rotor 140 via thecross-roller bearing 130 and thesecond bearing 150. Thestationary portion 2 includes ashaft 20, astator 21, abracket 22, acover 23, asubstrate 24, acable 25, asensor 26, and flexible printed circuits (FPC) 27. - The
shaft 20 is a fixed shaft. Theshaft 20 includes a through-hole 20 a penetrating in the axial direction. In particular, the through-hole 20 a is a space that penetrates thepost portion 201, as well as adisk portion 2021 and atube portion 2022 of alid portion 202, as described below. - Furthermore, the
shaft 20 includes thepost portion 201 extending along the center axis CA and thelid portion 202 provided at one end (upper end) of thepost portion 201 in the axial direction. Thepost portion 201 is a cylindrical hollow member penetrated by the through-hole 20 a. Moreover, thepost portion 201 and thelid portion 202 may be different members provided separately from each other as shown inFIG. 2 , but may be coupled to each other to form a single member. - The
lid portion 202 includes thedisk portion 2021 and thetube portion 2022. Thedisk portion 2021 extends radially outward from thepost portion 201 when viewed from the axial direction. Thetube portion 2022 extends downward in the axial direction from an inner peripheral portion of thedisk portion 2021 in the radial direction. Thetube portion 2022 extends from thedisk portion 2021 toward thepost portion 201 in the axial direction, and is coupled to one end of thepost portion 201 in the axial direction. The inner diameter of a lower portion of thetube portion 2022 in the axial direction is slightly larger than the outer diameter of an upper portion of thepost portion 201 in the axial direction. Therefore, thetube portion 2022 is coupled to the upper portion of thepost portion 201 in the axial direction by fitting the upper portion of thepost portion 201 in the axial direction into the lower portion of thetube portion 2022 in the axial direction. - The
stator 21 faces themagnet holding member 13 of thefirst rotor 1 in the radial direction to drive thefirst rotor 1. Thebracket 22 is a member accommodating thestator 21 therein and holding thestator 21. Thebracket 22 includes awall portion 221 as shown inFIG. 2 . In particular, themotor 110 includes thewall portion 221, and thewall portion 221 faces, radially outward of themagnet holding member 13, themagnet holding member 13 in the radial direction. Thecover 23 accommodates thestator 21 and a lower portion of thesubstrate 24 in the axial direction, and is attached to thebracket 22. Furthermore, thecovers 23 are, for example, fixed to the first arm R1, the second arm R2 and the joint shaft R3, at the first to third joint portions of the articulated robot R (seeFIG. 1 ), respectively. In particular, thecover 23 of the actuator 100 a is fixed to one end of the first arm R1. Thecover 23 of theactuator 100 b is fixed to one end of the second arm R2. Thecover 23 of theactuator 100 c is fixed to one end of the joint shaft R3. - The
substrate 24 is attached to a lower surface of thebracket 22 at a lower end of themotor 110 in the axial direction. In particular, thesubstrate 24 is provided on a side opposite to thesensor 26 with thepost portion 201 interposed therebetween in the axial direction. Thesubstrate 24 is electrically connected to thestator 21, and further electrically connected to thesensor 26 via acable 25 and anFPC 27. Thesubstrate 24 carries a control circuit (not shown), a communication circuit (not shown), and the like. The control circuit has functions of performing drive control of themotor 110, and controlling a rotational position of thesecond rotor 140. The communication circuit contains an input/output terminal complying with, for example, the Ethernet standard, and has a function of communicating with a device outside theactuator 100. Therefore, it is possible to control theactuator 100 using an external device connected to the communication circuit. - The
cable 25 is a wiring passing inside the through-hole 20 a, and electrically connects thesensor 26 and thesubstrate 24. Consequently, thesensor 26 for detecting a rotational position of a sensor magnet 146 (described later) is connected to thesubstrate 24 via thecable 25 communicating inside of the through-hole 20 a in the axial direction, which penetrates theshaft 20 and thepost portion 201 in the axial direction. Accordingly, thecable 25, which electrically connects thesensor 26 and thesubstrate 24, does not have to pass through, for example, outside of thestationary portion 2, radially outward of theshaft 20 in the radial direction. Therefore, theactuator 100 can be downsized in the radial direction. - The
sensor 26 is, for example, a Hall element, which is provided on thelid portion 202. Thesensor 26 faces a portion of a trajectory of thesensor magnet 146 rotating in the circumferential direction to detect a rotational position of thesensor magnet 146. Thesensor 26 may be at a position in the axial direction facing a portion of the trajectory of thesensor magnet 146 rotating in the circumferential direction, or at a position in the radial direction facing a portion of the trajectory of thesensor magnet 146 rotating in the circumferential direction, as shown inFIG. 2 . - The
FPC 27 is a bendable printed circuit board on which thesensor 26 is mounted, and is affixed to the lower surface of thedisk portion 2021. - The
first bearing 3 is provided between thefirst rotor 1 and theshaft 20 of thestationary portion 2. In particular, thefirst bearing 3 is provided between thefirst tube portion 11 and thepost portion 201. Thefirst bearing 3 rotatably supports thefirst rotor 1 with respect to thestationary portion 2. For example, a ball bearing can be used as thefirst bearing 3. Thefirst bearing 3 is fixed to thefirst rotor 1, and to thepost portion 201 of theshaft 20 provided in thestationary portion 2, as shown inFIG. 2 . In particular, an inner ring of thefirst bearing 3 is fixed to an outer surface of thepost portion 201. Meanwhile, an outer ring of thefirst bearing 3 is fixed to an inner surface of thefirst tube portion 11 of thefirst rotor 1. - The
first bearing 3 is disposed above a magnetic circuit of themotor 110 in the axial direction, which includes therotor magnet 14, thestator 21, etc., and does not overlap with the magnetic circuit in the radial direction. Therefore, it is possible to downsize theactuator 100 by increasing a size in the radial direction of the magnetic circuit of themotor 110, or decreasing a size in the radial direction of theactuator 100, as compared with a case where thefirst bearing 3 overlaps with the magnetic circuit in the radial direction. - The
lubricant 4 is, for example, grease, and is filled in a filling space S including at least a portion of a space between an outer surface of thefirst tube portion 11 and an inner surface of asecond tube portion 143. - The
width reducing portion 5 reduces a width of the filling space S in the radial direction in at least a portion of the filling space S in the axial direction. Consequently, a flow of thelubricant 4 leaking from the filling space S to the outside is suppressed by thewidth reducing portion 5. Accordingly, it is possible to reduce thelubricant 4 leaking from the filling space S to the outside. Therefore, it is possible to suppress leakage of thelubricant 4 with a simple configuration. - The
width reducing portion 5 includes at least one of a sealingmember 51 and agap member 52. The sealingmember 51 is in the shape of a plate extending in the radial direction and annular when viewed from the axial direction. InFIG. 2 , the sealingmember 51 forms a first gap S1 with thefirst tube portion 11. Thegap member 52 is annular when viewed from the axial direction. Thegap member 52 forms a second gap S2 with thesecond tube portion 143 inFIG. 2 . In particular, thegap member 52 forms the second gap S2 with ahat gear 122. A configuration of thewidth reducing portion 5 will be described later. - A configuration of the
speed reducer 120 will be described below. Thespeed reducer 120 reduces the rotation of thefirst rotor 1 and transmits the torque to thesecond rotor 140 via anelastic bearing 124. In this embodiment, Flexwave (registered trademark, manufactured by Nidec-Shimpo Corporation), which is a wave gear device having a reduction ratio of 1/100, is adopted as thespeed reducer 120, but the present disclosure is not limited to the example of the embodiment. Other reducer such as a planetary gear device may be used as thespeed reducer 120 of theactuator 100. - The
speed reducer 120 includes aninternal gear 121, ahat gear 122, acam 123, and anelastic bearing 124, as shown inFIG. 2 . - The
internal gear 121 is an internal gear having rigidity, in which teeth aligned in the circumferential direction are formed on an inner surface in the radial direction. Theinternal gear 121 is connected to an inner ring of thecross-roller bearing 130 and a drive output portion 141 (described later) of thesecond rotor 140, and is rotatable together with those components in the circumferential direction. - The
hat gear 122 includes a cylindrical portion extending in the axial direction, and an annular portion covering an upper end of the cylindrical portion in the axial direction. Thepost portion 201 of theshaft 20 is inserted into an opening provided at the center of the annular portion. The cylindrical portion of thehat gear 122 is deformable in the radial direction. An outer surface of the cylindrical portion in the radial direction has teeth formed in the circumferential direction. The number of the teeth is smaller than the number of the teeth formed on an inner surface of theinternal gear 121. - The
cam 123 has an elliptical shape when viewed from the axial direction, and is fixed to thefirst rotor 1 so as to be rotatable together with thefirst rotor 1. Thecam 123 is formed with an opening penetrating in the axial direction at its center. Thecam 123 is rotatable about the center axis CA with respect to thepost portion 201 by inserting thepost portion 201 of theshaft 20 into the opening of thecam 123. - The
elastic bearing 124 is a radially deformable bearing, and is provided on an outer surface of thecam 123 along an outer peripheral portion of theelliptical cam 123. Theelastic bearing 124 is held by thefirst rotor 1 radially outward of thefirst bearing 3, and rotatably supports thesecond rotor 140. An inner ring of theelastic bearing 124 is fixed to thecam 123, is attached to thefirst rotor 1 via thecam 123, and is rotatable together with thefirst rotor 1 in the circumferential direction. - The
elastic bearing 124 is accommodated inside the cylindrical portion of thehat gear 122, and deforms the cylindrical portion of thehat gear 122 in the radial direction in response to a shape of thecam 123. In particular, theelastic bearing 124 deflects the cylindrical portion of thehat gear 122 by pushing the cylindrical portion in the radial direction, so that the teeth formed on an outer surface of the deflected portion are partially engaged with the teeth formed on the inner surface of theinternal gear 121. Furthermore, theelastic bearing 124 moves a position at which thehat gear 122 and theinternal gear 121 are partially engaged in the circumferential direction by rotating theelastic bearing 124 together with thefirst rotor 1. At this time, theinternal gear 121 having more teeth than thehat gear 122 rotates at a lower speed than that of thehat gear 122 in response to a difference between the number of teeth ofhat gear 122 and the number of teeth of theinternal gear 121. Accordingly, thespeed reducer 120 rotates thesecond rotor 140 connected to theinternal gear 121 at a lower speed than that of thefirst rotor 1 inputting the driving force of theelastic bearing 124 and thehat gear 122. - A configuration of the
second rotor 140 will be described. Thesecond rotor 140 is rotatable about the center axis CA in the circumferential direction. Thesecond rotor 140 includes adrive output portion 141, arotation transmission portion 142, a tubularsecond tube portion 143, arotor support portion 144, amagnet support portion 145, and asensor magnet 146. - The
drive output portions 141 are connected to the working unit, the first arm R1 and the second arm R2, at the first to third joint portions of the articulated robot R (seeFIG. 1 ), respectively. Thedrive output portions 141 output the driving force of theactuator 100 to the working unit, the first arm R1 and the second arm R2. In particular, thedrive output portion 141 of the actuator 100 a is connected to the working unit and outputs the driving force to the working unit. Thedrive output portion 141 of theactuator 100 b is connected to the first arm R1 and outputs the driving force to the first arm R1. Thedrive output portion 141 of theactuator 100 c is connected to the second arm R2 and outputs the driving force to the second arm R2. - The
rotation transmission portion 142 is connected to thedrive output portion 141 and thesecond tube portion 143, and is rotatable together with thedrive output portion 141 and thesecond tube portion 143 in the circumferential direction. Therotation transmission portion 142 transmits the driving force, input from thefirst rotor 1 and reduced in the rotation speed by thespeed reducer 120, to the second rotor 140 (in particular, the drive output portion 141). Therotation transmission portion 142 is the same member as theinternal gear 121 of thespeed reducer 120 in this embodiment. That is, theinternal gear 121 functions as therotation transmission portion 142. However, therotation transmission portion 142 is not limited to this example, and may be a different member from theinternal gear 121. In a case where therotation transmission portion 142 is a different member, therotation transmission portion 142 is connected to theinternal gear 121. - The
second tube portion 143 extends in the axial direction, and is provided radially outward of thefirst tube portion 11. Thesecond tube portion 143 is connected to therotation transmission portion 142. Thesecond tube portion 143 is the same member as the inner ring of thecross-roller bearing 130 in this embodiment. That is, the inner ring of the cross-roller bearing 130 functions as thesecond tube portion 143. However, thesecond tube portion 143 is not limited to this example, and may be a different member from the inner ring of thecross-roller bearing 130. In a case where thesecond tube portion 143 is a different member, thesecond tube portion 143 is connected to the inner ring of thecross-roller bearing 130. - The
rotor support portion 144 positions an attachment position of thesecond bearing 150 to thedrive output portion 141. Moreover, themagnet support portion 145 supports thesensor magnet 146. Thesensor magnet 146 is provided on thesecond rotor 140 and is rotatable together with thesecond rotor 140 in the circumferential direction. In this embodiment, thesensor magnet 146 is provided with different magnetic poles formed alternately in the circumferential direction, and is disposed facing thesensor 26 in the radial direction. However, thesensor magnet 146 is not limited to the example of this embodiment, and may be configured to have a plurality of magnet pieces having different magnetic poles alternately arranged in the circumferential direction. - A configuration of the
width reducing portion 5 will be described with reference to first to third exemplified configurations. - First, a first exemplified configuration of the
width reducing portion 5.FIG. 3 is a cross-sectional view illustrating the first exemplified configuration of thewidth reducing portion 5.FIG. 3 corresponds to a part surrounded by a broken line inFIG. 2 . In the first exemplified configuration, thewidth reducing portion 5 includes the sealingmember 51 and thegap member 52 as shown inFIG. 3 . - The sealing
member 51 is provided at an upper end of thewall portion 221 of thebracket 22 in the axial direction, and extends radially inward from the upper end of thewall portion 221. In a case where thewidth reducing portion 5 includes at least the sealingmember 51, an outer end of the sealingmember 51 in the radial direction is provided on the wall portion 211; in particular, the outer end of the sealingmember 51 is fixed to an upper surface of the wall portion 211. An inner end of the sealingmember 51 in the radial direction faces thefirst tube portion 11, and forms a minute first gap S1 with the outer surface of thefirst tube portion 11 in the radial direction. Moreover, a gap between the sealingmember 51 and thefirst tube portion 11 in the axial direction (that is, the shortest distance therebetween, and a width W of the first gap S1 in the radial direction) is, for example, 0.05 mm. It is possible to suppress a flow of thelubricant 4 leaking from the filling space S to the outside by providing the sealingmember 51 in the filling space S. Even though the sealingmember 51 is provided in the filling space S, the volume of the filling space S is not reduced so much. Therefore, leakage of thelubricant 4 can be suppressed without significantly reducing a filling amount of thelubricant 4 in the filling space S. - The
gap member 52 is provided on the first tube portion inFIG. 3 . A position of thegap member 52 in the axial direction is determined by theprotrusion portion 11 a. In particular, when thegap member 52 is provided on thefirst tube portion 11, a lower end of thegap member 52 in axial direction is in contact with an upper surface of theprotrusion portion 11 a, thereby positioning thegap member 52 in the axial direction. Moreover, theprotrusion portion 11 a is coupled with thefirst tube portion 11 inFIG. 3 , but is not limited to this example. Theprotrusion portion 11 a may not be coupled with thefirst tube portion 11. That is, theprotrusion portion 11 a may protrude axially upward from thecircular plate portion 12 at a position away from thefirst tube portion 11 in the radial direction. - The
gap member 52 includes aninclined portion 521 upward in the axial direction. Theinclined portion 521 of thegap member 52 includes, axially upward, aninclined surface 521 a intersecting the axial direction. InFIG. 3 , an outer peripheral edge of theinclined surface 521 a on a side of thesecond tube portion 143 is disposed axially upward of an inner peripheral edge of theinclined surface 521 a on a side of thefirst tube portion 11. In particular, an upper portion of thegap member 52 in the axial direction is theinclined portion 521, and an upper surface of thegap member 52 toward theelastic bearing 124 is theinclined surface 521 a. Consequently, thegap member 52 having theinclined surface 521 a can be easily manufactured. A shape of thegap member 52 is simple, thus a strength of thegap member 52 can be enhanced as compared with a case where such a shape is complicated. - In the first exemplified configuration, the
lubricant 4 filled in the filling space S flows through a space having a labyrinth structure established by the sealingmember 51 and thegap member 52.FIG. 4 is a cross-sectional view illustrating a flow of thelubricant 4 in the first exemplified configuration. As shown inFIG. 4 , the sealingmember 51 forms the first gap S1, and thegap member 52 forms the second gap S2. Furthermore, the sealingmember 51 is provided between thegap member 52 and thecircular plate portion 12 of thefirst rotor 1 in the axial direction. Consequently, a labyrinth structure space can be formed in the filling space S filled with thelubricant 4. Thelubricant 4 flows through the labyrinth structure space when flowing from the filling space S to the outside. In particular, thelubricant 4 needs to pass through the second gap S2 formed by theannular gap member 52, a space between the annular sealingmember 51 and theannular gap member 52, the first gap S1 between the inner end of the annular sealingmember 51 in the radial direction and thefirst tube portion 11, and a space between the annular sealingmember 51 and thecircular plate portion 12 having the annular shape. Accordingly, thelubricant 4 hardly flows from the filling space S to the outside. Therefore, it is possible to further suppress leakage of thelubricant 4. - The outer end of the sealing
member 51 in the radial direction is not limited to the examples ofFIGS. 3 and 4 , and may be provided at a lower end of thehat gear 122 provided in the speed reducer in the axial direction. That is, in a case where thewidth reducing portion 5 includes at least the sealingmember 51, the outer end of the sealingmember 51 in the radial direction may be provided on thespeed reducer 120. - In a case where the
second tube portion 143 directly faces the filling space S and is directly in contact with thelubricant 4, thegap member 52 may be provided on thesecond tube portion 143.FIG. 5 is a cross-sectional view illustrating a modification example of the first exemplified configuration of thewidth reducing portion 5.FIG. 5 corresponds to a part surrounded by a broken line inFIG. 2 . Thegap member 52 provided on thesecond tube portion 143 forms a third gap S3 with thefirst tube portion 11 as shown inFIG. 5 . Furthermore, the inner peripheral edge of theinclined surface 521 a of theinclined portion 521 on a side of thefirst tube portion 11 is axially upward of the outer peripheral edge of theinclined surface 521 a on a side of thesecond tube portion 143, as shown inFIG. 5 . - As stated above, the
gap member 52 may be provided on one member of thefirst tube portion 11 and thesecond tube portion 143. Thegap member 52 forms the second gap S2 or the third gap S3 with the other member of thefirst tube portion 11 and thesecond tube portion 143 in the radial direction. By providing thegap member 52 in the filling space S, the longer the second gap S2 in the axial direction is, the harder thelubricant 4 flowing through the second gap S2 or the third gap S3 flows. Therefore, it is possible to suppress flow of thelubricant 4 leaking from the filling space S to the outside according to the length of the second gap S2 or the third gap S3 in the axial direction. - In a case where the
second tube portion 143 directly faces the filling space S and is directly in contact with thelubricant 4, as shown inFIG. 5 , aprotrusion portion 143 a may be provided on thesecond tube portion 143 to position thegap member 52 in the axial direction. Theprotrusion portion 143 a protrudes in the radial direction from thesecond tube portion 143 toward thefirst tube portion 11. When providing thegap member 52 on thesecond tube portion 143, a lower end of thegap member 52 in the axial direction is in contact with an upper surface of theprotrusion portion 143 a, thereby positioning thegap member 52 in the axial direction. - As state above, one member of the
first tube portion 11 and thesecond tube portion 143 may include aprotrusion portion gap member 52 is in contact with theprotrusion portion gap member 52 in the axial direction is determined by theprotrusion portion gap member 52 in the axial direction is in contact with an upper surface of theprotrusion portion gap member 52 is positioned in the axial direction by theprotrusion portion gap member 52 can be attached more easily, and the attachment work can be carried out with the improved efficiency. - Furthermore, in a case where the
second tube portion 143 directly faces the filling space S and is directly in contact with thelubricant 4, the outer end of the sealingmember 51 in the radial direction may be provided at a lower end of thesecond tube portion 143 in the axial direction. That is, in a case where thewidth reducing portion 5 includes at least the sealingmember 51, the outer end of the sealingmember 51 in the radial direction may be provided on thesecond tube portion 143. - In the configuration where the sealing
member 51 and thegap member 52 are provided on thesecond tube portion 143, thespeed reducer 120 may be, for example, a planetary speed reducer other than the wave gear device. - The
gap member 52 is a member different from one member of thefirst tube portion 11 and thesecond tube portion 143 inFIGS. 3 to 5 . However, the configuration of thegap member 52 is not limited to these examples.FIG. 6 is a cross-sectional view illustrating another modification example of the first exemplified configuration of thewidth reducing portion 5.FIG. 6 corresponds to a part surrounded by a broken line inFIG. 2 . In a case where thewidth reducing portion 5 includes at least thegap member 52 as shown inFIG. 6 , thegap member 52 may be integrally formed with one of thefirst tube portion 11 and thesecond tube portion 143. In particular, thegap member 52 provided on thefirst tube portion 11 may form a single member with thefirst tube portion 11, and in other words, may be a portion of thefirst tube portion 11, as shown inFIG. 6 . Thegap member 52 provided on thesecond tube portion 143 may form a single member with thesecond tube portion 143, and in other words, may be a portion of thesecond tube portion 143. Consequently, the number of components in theactuator 100 can be decreased, thus it is possible to suppress increase in manufacturing cost, and to sufficiently improve production efficiency. Moreover, thegap member 52 may be made of the same material as that of one member of thefirst tube portion 11 and thesecond tube portion 143, or a different material from that of the one member. - In the
gap member 52, a peripheral edge of theinclined surface 521 a of theinclined portion 521 in the radial direction on a side of one member of thefirst tube portion 11 and thesecond tube portion 143 is closer to a side of theelastic bearing 124 in the axial direction than a peripheral edge on a side of the other member. Furthermore, as illustrated inFIGS. 3 to 5 , an inclination angle θ of theinclined surface 521 a with respect to the axial direction from thegap member 52 toward theelastic bearing 124 is an acute angle. Consequently, thelubricant 4 hardly flows toward the second gap S2 or the third gap S3 by theinclined surface 521 a. Therefore, it is possible to further suppress leakage of thelubricant 4. - In
FIGS. 3 to 6 , the entire upper surface of thegap member 52 in the axial direction is theinclined surface 521 a. However, the configuration of theinclined surface 521 a is not limited to these examples. Theinclined portion 521 may be a portion of the upper portion of thegap member 52 in the axial direction. Furthermore, theinclined surface 521 a may be a portion of an upper surface of theinclined portion 521.FIG. 7 is a cross-sectional view illustrating another example of theinclined portion 521 and theinclined surface 521 a.FIG. 7 corresponds to a part surrounded by a broken line inFIG. 2 . - As shown in
FIG. 7 , theinclined portion 521 may be a portion of the upper portion of thegap member 52 in the axial direction. Furthermore, theinclined portion 521 may protrude axially upward from the upper surface of thegap member 52; in particular, theinclined portion 521 may protrude axially upward from a partial region of the upper surface in the radial direction. Theinclined portion 521 may extend in the circumferential direction, and is preferably annular. In this case, theinclined portion 521 overlaps with the upper surface of thegap member 52 when viewed from the axial direction. The upper surface is a surface of thegap member 52 toward theelastic bearing 124. “Axially upward” means a side of theelastic bearing 124 in the axial direction. Consequently, the volume of the filling space S reduced by thegap member 52 is smaller as compared with a case where the upper surface of thegap member 52 is theinclined surface 521 a. Additionally, thelubricant 4 hardly flows to the second gap S2 by theinclined surface 521 a. Therefore, it is possible to further suppress leakage of thelubricant 4 while suppressing reduction of the amount of thelubricant 4 fillable in the filling space S. - A position of the
inclined portion 521 in the radial direction in the upper surface of thegap member 52 is radially outward of an inner surface of thegap member 52. Such a position may also be radially inward of an outer surface of thegap member 52, and preferably overlaps with the inner surface or the outer surface of thegap member 52 when viewed from the axial direction. In particular, the peripheral edge of theinclined surface 521 a preferably overlaps with a peripheral edge of thegap member 52 in, rather than a side of one member of the of thefirst tube portion 11 and thesecond tube portion 143, a side of the other member in the radial direction, when viewed from the axial direction. That is, in a case where thegap member 52 is provided on thefirst tube portion 11, the peripheral edge of theinclined surface 521 a preferably overlaps with an outer peripheral edge of thegap member 52, radially outward, i.e., closer to a side of thesecond tube portion 143 than a side of thefirst tube portion 11 in the radial direction, when viewed from the axial direction. In a case where thegap member 52 is provided on thesecond tube portion 143, the peripheral edge of theinclined surface 521 a preferably overlaps with an inner peripheral edge of thegap member 52, radially inward, i.e. closer to a side of thefirst tube portion 11 than a side of thesecond tube portion 143 in the radial direction, when viewed from the axial direction. Consequently, thelubricant 4 further hardly flows toward the second gap S2 or the third gap S3. - The
width reducing portion 5 includes both of the sealingmember 51 and thegap member 52 in the first exemplified configuration. However, thewidth reducing portion 5 is not limited to the example of the first exemplified configuration, and may be configured to include one of the sealingmember 51 and thegap member 52 without the other one. -
FIG. 8 is a cross-sectional view illustrating a second exemplified configuration of thewidth reducing portion 5.FIG. 8 corresponds to a part surrounded by a broken line inFIG. 2 . In the second exemplified configuration, the width reducing portion includes the sealingmember 51 but does not include thegap member 52, as shown inFIG. 8 . Additionally, the outer end of the sealingmember 51 in the radial direction is provided on thewall portion 221 as shown inFIG. 8 . - Alternatively, the outer end of the sealing
member 51 in the radial direction is not limited to the example ofFIG. 8 , and may be provided on one of thespeed reducer 120 or thesecond tube portion 143. In particular, the outer end of the sealingmember 51 in the radial direction may be provided at the lower end of thehat gear 122 of thespeed reducer 120. Furthermore, in a case where thesecond tube portion 143 directly faces the filling space S and is directly in contact with thelubricant 4, the outer end of the sealingmember 51 in the radial direction may be provided on a lower portion of thesecond tube portion 143 in the axial direction. - In the second exemplified configuration, the
lubricant 4 needs to pass through, when flowing from the filling space S to the outside, the first gap S1 between the inner end of the annular sealingmember 51 in the radial direction and thefirst tube portion 11, and a space between the annular sealingmember 51 and thecircular plate portion 12 having the annular shape. Accordingly, thelubricant 4 hardly flows from the filling space S to the outside as compared with a configuration where the sealingmember 51 is not provided on theactuator 100. Therefore, it is possible to suppress leakage of thelubricant 4 by the sealingmember 51. -
FIG. 9 is a cross-sectional view illustrating a third exemplified configuration of thewidth reducing portion 5.FIG. 9 corresponds to a part surrounded by a broken line inFIG. 2 . In the third exemplified configuration, thewidth reducing portion 5 includes at least thegap member 52, as shown inFIG. 9 . Thegap member 52 is provided on thefirst tube portion 11 and is in contact with thecircular plate portion 12. Furthermore, thegap member 52 forms the second gap S2 with thesecond tube portion 143 in the radial direction. In particular, thegap member 52 forms the second gap S2 with the cylindrical portion of thehat gear 122 extending in the axial direction. Consequently, it is possible to position thegap member 52 in the axial direction by thecircular plate portion 12 of thefirst rotor 1. Therefore, thegap member 52 can be attached more easily, and the attachment work can be carried out with the improved efficiency. - In the third exemplified configuration, the
lubricant 4 needs to pass through, when flowing from the filling space S to the outside, the second gap S2 formed by theannular gap member 52. Accordingly, thelubricant 4 hardly flows from the filling space S to the outside as compared with a configuration where thewidth reducing portion 5 is not provided on theactuator 100. Therefore, it is possible to suppress leakage of thelubricant 4 by thegap member 52. - The embodiments of the present disclosure have been described above. The scope of the present disclosure is not limited to the embodiments stated above. Features of the above-described preferred embodiments and the modifications thereof may be combined appropriately as long as no conflict arises.
- While preferred embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims.
- The present disclosure is useful for an actuator attached to the robot or the like.
Claims (15)
1-14. (canceled)
15. An actuator comprising:
a motor including a first rotor rotatable in a circumferential direction about a center axis extending in a vertical direction, and a stator to drive the first rotor;
a second rotor rotatable in the circumferential direction about the center axis; and
a speed reducer that reduces rotation of the first rotor and transmits a torque to the second rotor, via a bearing; wherein
the first rotor includes a first tube portion extending in an axial direction;
the second rotor includes a second tube portion extending in the axial direction;
the second tube portion is radially outward of the first tube portion;
a lubricant is filled in a filling space including at least a portion of a space between an outer surface of the first tube portion and an inner surface of the second tube portion; and
the actuator further comprises a width reducing portion that reduces a width of the filling space in a radial direction in at least a portion of the filling space in the axial direction.
16. The actuator according to claim 15 , wherein
the width reducing portion includes at least one of a seal and a gap;
the seal has a plate shape extending in the radial direction and annular when viewed from the axial direction;
an inner end of the seal in the radial direction faces the first tube portion and defines a first gap with an outer surface of the first tube portion in the radial direction; and
the gap is annular when viewed from the axial direction, is provided on at least one of the first tube portion and the second tube portion, and defines a second gap with the other of the first tube portion and the second tube portion in the radial direction.
17. The actuator according to claim 16 , wherein
the width reducing portion includes at least the seal;
the motor includes a rotor magnet facing the stator, a magnet holder that holds the rotor magnet, and a wall radially facing the magnet holder radially outward of the magnet holder; and
an outer end of the seal in the radial direction is provided on the wall portion.
18. The actuator according to claim 16 , wherein
the width reducing portion includes at least the seal; and
an outer end of the seal in the radial direction is provided on one of the speed reducer and the second tube portion.
19. The actuator according to claim 16 , wherein
the width reducing portion includes at least the gap; and
the gap is integral with one of the first tube portion and the second tube portion.
20. The actuator according to claim 16 , wherein
the one of the first tube portion and the second tube portion includes a protrusion that protrudes toward the other of the first tube portion and the second tube portion in the radial direction; and
the gap is in contact with the protrusion in the axial direction.
21. The actuator according to claim 16 , wherein
the first rotor further includes a circular plate portion extending radially outward from the first tube portion;
the width reducing portion includes at least the gap; and
the gap is provided on the first tube portion and is in contact with the circular plate portion to define the second gap with the second tube portion in the radial direction.
22. The actuator according to claim 20 , wherein the protrusion includes a step that protrudes from the circular plate portion in the axial direction.
23. The actuator according to claim 16 , wherein
the first rotor further includes a circular plate portion extending radially outward from the first tube portion;
the width reducing portion includes the seal and the gap; and
the seal is provided between the gap and the circular plate portion in the axial direction.
24. The actuator according to claim 16 , wherein
the gap includes an inclined portion; and
in the inclined portion, a peripheral edge, of an inclined surface, on a side of the one of the first tube portion and the second tube portion in the radial direction is closer to a side of the bearing than a peripheral edge on a side of the other of the first tube portion and the second tube portion in the axial direction.
25. The actuator according to claim 24 , wherein an inclination angle of the inclined surface with respect to the axial direction from the gap toward the bearing is an acute angle.
26. The actuator according to claim 24 , wherein a surface of the gap facing the bearing defines the inclined surface.
27. The actuator according to claim 24 , wherein
the inclined portion protrudes from a surface of the gap facing the bearing toward a side of the bearing in the axial direction; and
the inclined portion overlaps with a portion of the surface of the gap facing the bearing when viewed from the axial direction.
28. The actuator according to claim 27 , wherein a peripheral edge of the inclined surface overlaps with a peripheral edge of the gap on a side of the other of the first tube portion and the second tube portion instead of the one of the first tube portion and the second tube portion in the radial direction, when viewed from the axial direction.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US16/303,234 US20190203825A1 (en) | 2016-05-27 | 2017-02-10 | Actuator |
Applications Claiming Priority (3)
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US201662342326P | 2016-05-27 | 2016-05-27 | |
US16/303,234 US20190203825A1 (en) | 2016-05-27 | 2017-02-10 | Actuator |
PCT/JP2017/004960 WO2017203754A1 (en) | 2016-05-27 | 2017-02-10 | Actuator |
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US20190203825A1 true US20190203825A1 (en) | 2019-07-04 |
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ID=60412170
Family Applications (2)
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US16/303,234 Abandoned US20190203825A1 (en) | 2016-05-27 | 2017-02-10 | Actuator |
US16/303,683 Active 2037-10-02 US11002355B2 (en) | 2016-05-27 | 2017-02-10 | Actuator with sensor on output flange |
Family Applications After (1)
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US16/303,683 Active 2037-10-02 US11002355B2 (en) | 2016-05-27 | 2017-02-10 | Actuator with sensor on output flange |
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US (2) | US20190203825A1 (en) |
JP (2) | JP6658877B2 (en) |
CN (2) | CN109155570B (en) |
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CN103758938B (en) * | 2014-01-15 | 2016-08-24 | 徐州科源液压股份有限公司 | Excavator rotary reducer |
CN104033579B (en) * | 2014-03-31 | 2016-06-15 | 南车株洲电力机车有限公司 | A kind of power transmission shaft dynamic sealing device |
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2017
- 2017-02-10 CN CN201780032075.XA patent/CN109155570B/en not_active Expired - Fee Related
- 2017-02-10 WO PCT/JP2017/004959 patent/WO2017203753A1/en active Application Filing
- 2017-02-10 WO PCT/JP2017/004960 patent/WO2017203754A1/en active Application Filing
- 2017-02-10 JP JP2018519084A patent/JP6658877B2/en not_active Expired - Fee Related
- 2017-02-10 CN CN201780032120.1A patent/CN109154380B/en not_active Expired - Fee Related
- 2017-02-10 US US16/303,234 patent/US20190203825A1/en not_active Abandoned
- 2017-02-10 JP JP2018519085A patent/JP6610780B2/en not_active Expired - Fee Related
- 2017-02-10 US US16/303,683 patent/US11002355B2/en active Active
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US20220397191A1 (en) * | 2019-11-22 | 2022-12-15 | Schaeffler Technologies AG & Co. KG | Flexible transmission component and method of manufacturing a transmission component |
US20220173634A1 (en) * | 2020-08-12 | 2022-06-02 | Joby Aero, Inc. | Compact Offset Outrunner Harmonic Drive Rotary Actuator And Deployment System Using Same |
US11942855B2 (en) * | 2020-08-12 | 2024-03-26 | Joby Aero, Inc. | Compact offset outrunner harmonic drive rotary actuator and deployment system using same |
EP4092202A1 (en) * | 2021-05-20 | 2022-11-23 | Nabtesco Corporation | Transmission with falling-off prevention feature |
US11781637B2 (en) | 2021-05-20 | 2023-10-10 | Nabtesco Corporation | Transmission with falling-off prevention feature |
EP4092882A3 (en) * | 2021-09-30 | 2023-09-13 | Shenzhen Pengxing Intelligent Research Co., Ltd. | Electric drive module and electric drive equipment |
Also Published As
Publication number | Publication date |
---|---|
WO2017203754A1 (en) | 2017-11-30 |
US11002355B2 (en) | 2021-05-11 |
JPWO2017203753A1 (en) | 2019-02-28 |
JP6610780B2 (en) | 2019-11-27 |
CN109154380B (en) | 2021-11-09 |
JPWO2017203754A1 (en) | 2019-02-28 |
WO2017203753A1 (en) | 2017-11-30 |
CN109155570A (en) | 2019-01-04 |
CN109155570B (en) | 2020-12-01 |
JP6658877B2 (en) | 2020-03-04 |
US20200321833A1 (en) | 2020-10-08 |
CN109154380A (en) | 2019-01-04 |
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