Patent Description:
Cooperative robots are conventionally known as robots that share a work space with a worker. For example, a multi-joint cooperative robot, which is one of such cooperative robots, is provided with a speed reducing mechanism as well as an electric motor that serve as a rotation mechanism at a joint where two arms of the robot are connected to each other. The electric motor applies a rotational force to the speed reducing mechanism. In the multi-joint cooperative robot, the rotational force of the electric motor is decelerated and outputted by the speed reducing mechanism, such that a larger output torque can be applied from one of the two arms to the other. <CIT> discloses a technique related to a wrist swing axis of an industrial robot. In <CIT>, a speed reducer is attached to the frame by bolts.

For small-sized speed reducers, use of resin as a component material is being considered to further reduce the size and weight.

<CIT> relates to robotic modules and connectors used therewith to configure and reconfigure the robotic system to perform a desired task. The robotic modules can comprise an actuated rotation joint associated with a coupling member including an elastic deformation portion and a claw portion.

<CIT> introduces an eccentrically oscillating type reduction gear for robots, emphasizing durability and impact resistance. It features internal and external gears, both crafted from resin to reduce weight while ensuring effective meshing. Additionally, it includes shock-absorbing elements to enhance impact resistance. <CIT> addresses the gear's design in terms of heat dissipation and its influence on lifespan due to temperature rises.

However, when the speed reducers are made of resin or the like for the purpose of reducing the size and weight, the assembly process at the connection between the speed reducer and the mating member using bolts may be complicated, considering the strength of the bolts and the mating member. Therefore, there was room for improvement in terms of simplifying assembly and disassembly work.

The present invention provides a speed reducing mechanism and a robot for which assembly and disassembly work efficiency can be improved.

A speed reducing mechanism according to the invention comprises: a case configured to output rotation to a mating member from a drive source, which is producing a rotational force around an axis; at least one crankshaft provided in the case and configured to rotate by receiving the rotation of the drive source; a carrier provided in the case and configured to decelerate rotation of the crankshaft; a coupling member configured to couple the mating member and the case by elastic deformation; and an anti-rotation portion configured to prevent relative rotation between the mating member and the case, wherein the case is fitted into a through hole formed to pass through the mating member in an axial direction along the axis, and an outer periphery of the case is in contact with an inner surface of the through hole, wherein the coupling member includes: an elastic deformation portion extending in the axial direction along the axis and capable of elastic deformation in a radial direction intersecting the axial direction; and a claw portion provided at a distal end of the elastic deformation portion and projecting in the radial direction, wherein the coupling couples the case fitted into the through hole in the axial direction against the mating member, wherein, in a state in which the coupling member couples the case and the mating member, the elastic deformation portion extends through the through hole along the axial direction, and the elastic deformation portion is in contact with the inner surface of the through hole by elastic deformation, wherein the anti-rotation portion is provided between the outer periphery of the case and the inner surface of the through hole, and wherein the case is prevented from rotating relative to through hole in a circumferential direction around the axis by the anti-rotation portion.

This configuration does not need fastening by bolts or the like for assembly, making it possible to improve work efficiency in assembling and disassembling the output portion and the mating member.

A robot according to the invention comprises: a first member and a second member; and the speed reducing mechanism described above provided between the first member and the second member and configured to rotate the second member relative to the first member, wherein the case outputs the rotational force of the drive source to the second member as the mating member, wherein the coupling member couples the second member and the case by elastic deformation; and the anti-rotation portion prevents relative rotation between the second member and the case.

The present invention improves assembly and disassembly work efficiency.

The following describes a first embodiment of the invention with reference to the accompanying drawings. <FIG> schematically illustrates a cooperative robot according to the embodiment. In <FIG>, the reference sign <NUM> denotes the cooperative robot. In the following description, the vertical and horizontal directions of the cooperative robot <NUM> are defined as the vertical and horizontal directions when the cooperative robot <NUM> is placed on an installation surface F.

As shown in <FIG>, the cooperative robot <NUM> (robot) includes a base portion <NUM> (an example of a first member or a second member in the claims), a rotating head <NUM> (an example of the first member or the second member in the claims), an arm unit <NUM> (an example of the first member or the second member in the claims), speed reducing mechanisms 1A, 1B, and 1C (first speed reducing mechanism 1A, second speed reducing mechanism 1B, and third speed reducing mechanism 1C), servomotors <NUM>, <NUM> and <NUM> (first servomotor <NUM>, second servomotor <NUM>, and third servomotor <NUM>), and an end effector <NUM>. The base portion <NUM> is placed on the installation surface F. The rotating head <NUM> is provided on the base portion <NUM>. The arm unit <NUM> is rotatably assembled to the top of the rotating head <NUM>. The speed reducing mechanisms 1A, 1B, and 1C are assembled to a joint portion 106a of the base portion <NUM>, a joint portion 106b of the rotating head <NUM>, and a joint portion 106c of the arm unit <NUM>. The servomotors <NUM>, <NUM>, and <NUM> serve as drive sources. The end effector <NUM> is attached to the arm unit <NUM>.

The rotating head <NUM> is coupled to the base portion <NUM> so as to be rotatable around a first rotation axis L1. The portion at which the base portion <NUM> is coupled to the rotating head <NUM> constitutes the first joint portion 106a. The first speed reducing mechanism 1A and the first servomotor <NUM> are assembled to the first joint portion 106a. The first rotation axis L1 coincides with, for example, the vertical direction. Rotation of the first servomotor <NUM> is transmitted to the rotating head <NUM> via the first speed reducing mechanism 1A. In this way, the rotating head <NUM> is rotationally driven relative to the base portion <NUM> around the first rotation axis L1.

The arm unit <NUM> includes, for example, two arms <NUM> and <NUM> (first arm <NUM> and second arm <NUM>) each extending in one direction. A first end of the first arm <NUM> is coupled to the upper portion of the rotating head <NUM> so as to be rotatable about a second rotation axis L2. The portion at which the first end of the first arm <NUM> is coupled to the upper end of the rotating head <NUM> constitutes the second joint portion 106b. The second speed reducing mechanism 1B and the second servomotor <NUM> are assembled to the second joint portion 106b.

The second rotation axis L2 coincides with, for example, the horizontal direction. Rotation of the second servomotor <NUM> is transmitted to the first arm <NUM> via the second speed reducing mechanism 1B. In this way, the first arm <NUM> is rotationally driven relative to the rotating head <NUM> around the second rotation axis L2. The first arm <NUM> is driven to swing in the front and rear directions relative to the base portion <NUM>.

A first end of the second arm <NUM> is coupled to a second end of the first arm <NUM> so as to be rotatable about a third rotation axis L3. The portion at which the first end of the second arm <NUM> is coupled to the second end of the first arm <NUM> constitutes the third joint portion 106c. The third speed reducing mechanism 1C and the third servomotor <NUM> are assembled to the third joint portion 106c. The third rotation axis L3 coincides with, for example, the horizontal direction. Rotation of the third servomotor <NUM> is transmitted to the second arm <NUM> via the third speed reducing mechanism 1C. In this way, the second arm <NUM> is rotationally driven relative to the first arm <NUM> about the third rotation axis L3. The second arm <NUM> is driven to swing in the upper and lower directions relative to the first arm <NUM>.

The end effector <NUM> is attached to a second end of the second arm <NUM>. By driving the rotating head <NUM>, the first arm <NUM>, and the second arm <NUM>, the end effector <NUM> is three-dimensionally driven.

The base portion <NUM>, rotating head <NUM>, first arm <NUM>, and second arm <NUM>, which constitute the cooperative robot <NUM>, are made of, for example, aluminum alloys or other materials, such as magnesium alloys, carbon fiber reinforced plastics (CFRP), resins containing boron nitride, or POM (polyacetal), PAEK (Polyaryletherketones) represented by PEEK (polyetheretherketone), or other resins.

The speed reducing mechanisms 1A to 1C will be now described with reference to <FIG>. The basic configuration of the speed reducing mechanisms 1A to 1C is the same. Therefore, only the third speed reducing mechanism 1C will be hereunder described, and description of the first speed reducing mechanism 1A and the second speed reducing mechanism 1B will be omitted.

<FIG> schematically illustrates the third speed reducing mechanism (rotation mechanism) 1C. As shown in <FIG>, the third speed reducing mechanism 1C is what is called an eccentric oscillation speed reducing mechanism. The third speed reducing mechanism 1C includes a cylindrical case <NUM> (an example of an internal gear in the claims), a carrier <NUM> rotatably supported by the case <NUM>, an input crankshaft (crankshaft) <NUM> rotatably supported by the carrier <NUM>, a plurality of (for example, three) output shafts <NUM>, and oscillating gears <NUM> and <NUM> (first oscillating gear <NUM> and second oscillating gear <NUM>) rotatably supported by the input crankshaft <NUM>.

A central axis C1 of the case <NUM> coincides with the third rotation axis L3. In the following description, the direction parallel to the third rotation axis L3 may be referred to as the axial direction, the circumferential direction around the third rotation axis L3 may be referred to as the circumferential direction, and the direction orthogonal to the axial direction may be referred to as the radial direction.

The case <NUM> is made of, for example, POM (polyacetal). The case <NUM> may be made of a resin different from POM, such as PAEK (Polyaryletherketones) represented by PEEK (polyetheretherketone). The resin may be, for example, PPS (Polyphenylene sulfide) or a resin containing PPS. In the embodiment, the case <NUM> may be made of, for example, an aluminum alloy, a magnesium alloy, carbon fiber reinforced plastic (CFRP), or a resin containing boron nitride as long as reduction of the size and weight is possible.

An outer flange portion <NUM> projecting outward in the radial direction is formed on the outer periphery 2a of the case <NUM>. The outer flange portion <NUM> is located at an end of the case <NUM> in the axial direction and is formed integrally with the case <NUM>. The outer flange portion <NUM> has, for example, a rectangular section along the axial direction. The outer flange portion <NUM> has end surfaces 4a and 4b (first end surface 4a, second end surface 4b) facing in the axial directions. The outer flange portion <NUM> is not provided on the entire circumference of the case <NUM> because of case cutting (working of the case <NUM>), but is formed discontinuously in the circumferential direction of the case <NUM>. Therefore, the outer flange portion <NUM> may be invisible in the sectional view shown in <FIG>. Therefore, in <FIG>, the outer flange portion <NUM> is drawn by a double-dashed line.

The second end surface 4b of the outer flange portion <NUM> receives the first surface 112a of the second arm (mating member) <NUM> applied to and contacted with the second end surface 4b. A coupling member <NUM> is fixed to and contacted with the first end surface 4a of the outer flange portion <NUM>. The coupling member <NUM> is locked on the second arm <NUM> by a snap-fit structure. As a result, the outer flange portion <NUM> is sandwiched by the second arm <NUM> and the coupling member <NUM> in the axial direction. Thus, the case <NUM> fitted on the second arm <NUM> is fixed so that it does not move in the axial direction.

The inner peripheral surface 2b of the case <NUM> has a first large-diameter portion 3a and a second large-diameter portion 3b formed therein. The first large-diameter portion 3a is located in a first side of the case <NUM> (the end located on the rotating head <NUM> side) in the axial direction. The first large-diameter portion 3a and the inner peripheral surface 2b of the case <NUM> are connected via a first stepped portion 3c. The second large-diameter portion 3b is located at a second end of the case <NUM> in the axial direction. The second large-diameter portion 3b and the inner peripheral surface 2b of the case <NUM> are connected via a second stepped portion 3d. The inner diameters of the large-diameter portions 3a and 3b are larger than the inner diameter of the case <NUM>. The large-diameter portions 3a and 3b receive the carrier <NUM>.

A plurality of internal tooth pins <NUM> (an example of the internal gear in the claims) are provided on the inner peripheral surface 2b of the case <NUM> between the two stepped portions 3c and 3d. Each of the internal tooth pins <NUM> is formed of, for example, metal. However, this is not limitative. The internal tooth pins <NUM> may be made of, for example, a resin, non-metallic material or the like having a light weight. The internal tooth pins <NUM> may be made of a resin containing carbon nanotubes (CNT) or boron nitride nanotubes (BNNT). The internal tooth pins <NUM> may be made of ferrous metal such as bearing steel. The internal tooth pins <NUM> may be made of carbon fiber reinforced plastic (CFRP).

Each of the internal tooth pins <NUM> is shaped like a solid column. However, the internal tooth pins <NUM> are not necessarily solid but may be hollow. Each of the internal tooth pins <NUM> may be a multi-layered structure having a core material wrapped with a surface material. For example, one of the core and the surface material of the internal tooth pin <NUM> may be made of an iron-based metal, and the other may be made of a copper- or aluminum-based metal. Such a structure can combine good mechanical and density characteristics. As another example of the configuration of the internal tooth pin <NUM>, one of the core and the surface material may be made of metal, and the other may be made of resin. The internal tooth pins <NUM> may be made of sintered metal.

The axial direction of the internal tooth pins <NUM> coincides with the central axis C1 of the case <NUM>. The internal tooth pins <NUM> are arranged at regular intervals in the circumferential direction. The internal tooth pins <NUM> serve as internal teeth that mesh with the oscillating gears <NUM> and <NUM>.

The carrier <NUM> includes a first carrier (shaft flange) <NUM> provided on the first large-diameter portion 3a situated closer to the rotating head <NUM>, and a second carrier (hold flange) <NUM> provided on the second large-diameter portion 3b situated opposite to the first large-diameter portion 3a in the axial direction. Each of the carriers <NUM> and <NUM> is formed in a disc shape. The outer peripheral surfaces of the carriers <NUM> and <NUM> are slidably fitted to the large-diameter portions 3a and 3b, respectively. The carriers <NUM> and <NUM> are positioned relative to the case <NUM> in the axial direction by abutting against the corresponding stepped portions 3c and 3d.

The carriers <NUM> and <NUM> are made of resin, for example. The carriers <NUM> and <NUM> may be made of POM (polyacetal). Each of the carriers <NUM> and <NUM> may be formed of a resin different from POM, such as PAEK (Polyaryl Ether Ketones) represented by PEEK (Poly Ether Ether Ketone). The resin may be PPS (Poly Phenylene Sulfide) or a resin containing PPS. The carriers <NUM> and <NUM> may be made of carbon fiber reinforced plastic (CFRP).

The carriers <NUM> and <NUM> have input shaft holes 13a and 14a, respectively, formed at the center in the radial direction and extending through the carriers <NUM> and <NUM> in the axial direction. The input crankshaft <NUM> is inserted into the input shaft holes 13a and 14a. Bearings 15a and 15b (first bearing 15a and second bearing 15b) are provided in the input shaft holes 13a and 14a, respectively. The bearings 15a and 15b are ball bearings, for example. The input crankshaft <NUM> is rotatably supported by the carriers <NUM> and <NUM> via the bearings 15a and 15b. The rotation axis of the input crankshaft <NUM> coincides with the central axis C1 of the case <NUM> (third rotation axis L3).

In each of the carriers <NUM> and <NUM>, a plurality of (for example, eight) output shaft holes (shaft insertion holes) 13b and 14b are formed at equal intervals in the circumferential direction around the input shaft holes 13a and 14a. Output shafts <NUM> are inserted into the output shaft holes 13b and 14b. Thus, eight output shafts <NUM> are arranged at regular intervals in the circumferential direction. In a surface 13c of the first carrier <NUM> facing away from the second carrier <NUM>, there are formed shim receiving recesses <NUM> that are coaxial with the corresponding output shaft holes 13b. The shim receiving recesses <NUM> are open to the surface 13c and communicate with the corresponding output shaft holes 13b.

In each of the shim receiving recesses <NUM>, an elastic shim <NUM> having an annular shape is received. The inner diameter of the elastic shim <NUM> is approximately the same as or slightly larger than the inner diameter of the output shaft hole 13b. The elastic shim <NUM> is made of rubber or the like and elastically deforms. The elastic shim <NUM> may be made of a material other than rubber, provided that it is made of an elastically deformable material. For example, the rubber may be replaced with a wave washer as the elastic shim <NUM>.

A spacer <NUM> having an annular shape is disposed on the elastic shim <NUM>. The inner diameter of the spacer <NUM> is approximately the same as or slightly larger than the inner diameter of the output shaft hole 13b. The elastic shim <NUM> and the spacer <NUM> are provided for positioning the output shaft <NUM> with respect to the carriers <NUM> and <NUM>. The elastic shim <NUM> and the spacer <NUM> are not limited to the annular shape, but may have various shapes as long as they can absorb manufacturing errors of the case <NUM>, the carriers <NUM> and <NUM>, and the output shaft <NUM>.

In a surface 14c of the second carrier <NUM> facing away from the first carrier <NUM>, there are formed recesses <NUM> that are coaxial with the corresponding output shaft holes 14b. The recesses <NUM> are open in the surface 14c and communicate with the corresponding output shaft holes 14b. The recesses <NUM> may be filled with grease, for example. The output shaft <NUM> inserted in the output shaft holes 13b and 14b is made of, for example, aluminum alloy or ferrous metals such as stainless steel, carbon steel, or bearing steel.

A first end portion 9a of the output shaft <NUM> on the first carrier <NUM> side protrudes slightly outward beyond the surface 13c of the first carrier <NUM>. The elastic shim <NUM> and the spacer <NUM> are attached to the first end portion 9a of the output shaft <NUM>. A first retaining ring 18a is provided on the spacer <NUM> at the first end portion 9a of the output shaft <NUM>. Axial movement of the output shaft <NUM> toward the second carrier <NUM> is restricted by the first retaining ring 18a abutting against the spacer <NUM>.

A second end portion 9b of the output shaft <NUM> on the second carrier <NUM> side is positioned slightly inside the surface 14c of the second carrier <NUM>. That is, the second end portion 9b of the output shaft <NUM> is received in the recess <NUM> of the second carrier <NUM>. A second retaining ring 18b is provided on the second end portion 9b of the output shaft <NUM>. The second retaining ring 18b is received in the recess <NUM>. Axial movement of the output shaft <NUM> toward the first carrier <NUM> is restricted by the second retaining ring 18b abutting against a bottom surface 16a of the recess <NUM>.

The elastic shim <NUM>, the spacer <NUM>, and the retaining rings 18a and 18b serve to position the output shaft <NUM> relative to the carriers <NUM> and <NUM>. Among them, the elastic shim <NUM> and the spacer <NUM> serve to absorb manufacturing errors of the case <NUM>, the carriers <NUM> and <NUM>, and the output shaft <NUM> and adjust the position of the output shaft <NUM> relative to the carriers <NUM> and <NUM>. Specifically, the thicknesses of the elastic shim <NUM> and the spacer <NUM> in the axial direction should be adjusted depending on the amount of play of the output shaft <NUM> in the axial direction relative to the carriers <NUM> and <NUM>. This reduce the play of the output shaft <NUM> in the axial direction relative to the carriers <NUM> and <NUM>. The play is a looseness that allows the output shaft <NUM> to move in the axial direction relative to the carriers <NUM> and <NUM>, which is caused by manufacturing errors of the case <NUM>, the carriers <NUM> and <NUM>, and the output shaft <NUM>.

The thickness of the elastic shim <NUM> in the axial direction is determined such that the elastic shim <NUM> is slightly compressed. Thus, the first carrier <NUM> is biased toward the second carrier <NUM> by an elastic restoring force of the elastic shim <NUM>. This securely prevents the carriers <NUM> and <NUM> and the output shaft <NUM> from being loosened. Even if the play of the output shaft <NUM> in the axial direction relative to the carriers <NUM> and <NUM> increases due to aged deterioration or the like, this play can be absorbed by the elastic shim <NUM>. In addition, by biasing the first carrier <NUM> toward the second carrier <NUM>, preload can be applied to the bearings 15a and 15b disposed in the input shaft holes 13a and 14a, respectively.

Since the movement of the output shaft <NUM> in the axial direction relative to the carriers <NUM> and <NUM> is restricted, the movement of the carriers <NUM> and <NUM> in the axial direction is restricted. Thus, the carriers <NUM> and <NUM> are kept fitted to the corresponding large-diameter portions 3a and 3b of the case <NUM>, respectively. Therefore, the carriers <NUM> and <NUM> and the output shafts <NUM> are integrated together. Each of the output shafts <NUM> is inserted into the output shaft holes 13b and 14b of the carriers <NUM> and <NUM>. Therefore, the output shafts <NUM> are arranged around the input crankshaft <NUM>. Similar to the output shafts <NUM>, the input crankshaft <NUM> may be made of, for example, aluminum alloy, stainless steel or various ferrous metals.

A first end portion 8a of the input crankshaft <NUM> on the first carrier <NUM> side protrudes axially outward through the first bearing 15a. The third servomotor <NUM> (see <FIG>) is coupled to the first end portion 8a. Therefore, the rotation of the third servomotor <NUM> is transmitted to the input crankshaft <NUM>.

A second end 8b of the input crankshaft <NUM> on the second carrier <NUM> side is situated substantially flush with the end surface of the second bearing 15b that faces away from the first carrier <NUM>. The input crankshaft <NUM> has a first eccentric portion 21a and a second eccentric portion 21b arranged in the axial direction between the bearings 15a and 15b. The input crankshaft <NUM> has a large-diameter portion <NUM> positioned between the eccentric portions 21a and 21b. The diameter of the large-diameter portion <NUM> is larger than those of the eccentric portions 21a and 21b.

The first eccentric portion 21a is situated on the first carrier <NUM> side of the second eccentric portion 21b. The second eccentric portion 21b is situated on the second carrier <NUM> side of the first eccentric portion 21a. Each of the eccentric portions 21a, 21b is provided eccentrically with respect to the third rotation axis L3. The eccentric portions 21a and 21b are out of phase with each other. For example, the eccentric portions 21a and 21b are out of phase with each other by <NUM>°.

The first eccentric portion 21a carries a third bearing 15c. The second eccentric portion 21b carries a fourth bearing 15d. Similar to the first bearing 15a and the second bearing 15b, the bearings 15c and 15d are ball bearings, for example. The distance between the bearing 15c and the bearing 15d in the axial direction is regulated by abutment of the axial end surfaces of the bearings 15c and 15d against the large-diameter portion <NUM>. The oscillating gears <NUM> and <NUM> (the first oscillating gear <NUM> and the second oscillating gear <NUM>) are rotatably supported on the eccentric portions 21a and 21b via the bearings 15c and 15d, respectively.

The oscillating gears <NUM> and <NUM> are made of, for example, resin. For example, the oscillating gears <NUM> and <NUM> may be made of POM (polyacetal). Similarly to the material for the carriers <NUM> and <NUM> described above, various resins can be used for the oscillating gears <NUM> and <NUM>.

The oscillating gears <NUM> and <NUM> are arranged at a prescribed distance from each other between the carriers <NUM> and <NUM>. A first crankshaft insertion hole 24a is formed in the center of the first oscillating gear <NUM> in the radial direction to extend through the first oscillating gear <NUM> in the thickness direction (axial direction). The outer peripheral surface of the third bearing 15c is fitted to the first crankshaft insertion hole 24a. Thus, the first oscillating gear <NUM> is rotatably supported on the first eccentric portion 21a via the third bearing 15c. Rotation of the first eccentric portion 21a causes the first oscillating gear <NUM> to rotate oscillatorily. A second crankshaft insertion hole 24b is formed in the center of the second oscillating gear <NUM> in the radial direction to extend through the second oscillating gear <NUM> in the thickness direction (axial direction). The outer peripheral surface of the fourth bearing 15d is fitted to the second crankshaft insertion hole 24b. Thus, the second oscillating gear <NUM> is rotatably supported on the second eccentric portion 21b via the fourth bearing 15d. Rotation of the second eccentric portion 21b causes the second oscillating gear <NUM> to rotate oscillatorily.

The first oscillating gear <NUM> has external teeth 23a formed in the outer periphery thereof. The second oscillating gear <NUM> has external teeth 23b formed in the outer periphery thereof. The external teeth 23a and 23b are meshed with the internal tooth pins <NUM>. The number of teeth for each of the external teeth 23a and 23b is smaller than the number of the internal tooth pins <NUM> by, for example, one. The first oscillating gear <NUM> has first output shaft insertion holes 25a located at positions corresponding to the output shafts <NUM> and receiving the output shafts <NUM> inserted therein. The second oscillating gear <NUM> has second output shaft insertion holes 25b located at positions corresponding to the output shafts <NUM> and receiving the output shafts <NUM> inserted therein. The inner diameters of the output shaft insertion holes 25a and 25b are large enough to allow the oscillatory rotation of the oscillating gears <NUM> and <NUM> with the output shaft <NUM> inserted in the output shaft insertion holes 25a and 25b.

In the third speed reducing mechanism 1C, the surface 14c of the second carrier <NUM> receives, for example, the first arm (stationary member) <NUM> applied thereto. The first arm <NUM> is fixed to the second carrier <NUM> with bolts (not shown). The first arm <NUM> has a projection 111a that projects toward the second carrier <NUM>. The projection 111a is fitted into the input shaft hole 14a of the second carrier <NUM>. This accomplishes positioning of the first arm <NUM> in the radial direction with respect to the second carrier <NUM>. The projection 111a projects to such an extent that it faces the second bearing 15b and the second end portion 8b of the input crankshaft <NUM> with a minute gap therebetween.

As mentioned above, the coupling member <NUM> has a snap-fit structure. The coupling member <NUM> is locked on the second arm <NUM> through a through hole 112d formed in the second arm <NUM>. <FIG> is a schematic perspective view of the third speed reducing mechanism 1C and the second arm <NUM>. <FIG> is a perspective view of the coupling member <NUM>.

As shown in <FIG> and <FIG>, the coupling member <NUM> includes a ring portion <NUM> that contacts with the first end surface 2c of the case <NUM> over the entire circumference, elastic deformation portions <NUM> that extend along the axial direction from the outer periphery of the ring portion <NUM>, and claw portions <NUM> formed at the distal ends 32b of the elastic deformation portions <NUM>. The coupling member <NUM> is formed of the same material as the case <NUM>. The coupling member <NUM> is made of, for example, POM (polyacetal). The coupling member <NUM> may be made of a resin different from POM, such as PAEK (Polyaryletherketones) represented by PEEK (polyetheretherketone). The resin may be PPS (Poly Phenylene Sulfide) or a resin containing PPS. In the embodiment, the coupling member <NUM> may be made of, for example, an aluminum alloy, a magnesium alloy, carbon fiber reinforced plastic (CFRP), or a resin containing boron nitride as long as reduction of the size and weight is possible.

The surface of the ring portion <NUM> that faces in the direction in which the elastic deformation portions <NUM> extend is configured as a holding surface 31a. The holding surface 31a contacts with the first end surface 2c of the case <NUM> over the entire circumference. Further, the holding surface 31a contacts with the entire region of the first end surface 4a of the outer flange portion <NUM> in the axial direction. The inner periphery of the ring portion <NUM> is formed so that the outline of its cross section perpendicular to the axial direction is circular. The inner periphery of the ring portion <NUM> is separated from the carrier <NUM> (second carrier <NUM>) by a predetermined distance in the radial direction over the entire circumference. The inner diameter of the ring portion <NUM> is larger than the diameter of the surface 14c of the second carrier <NUM>.

In contrast, the outer periphery of the ring portion <NUM> has a noncircular outline. Specifically, the outer periphery of the ring portion <NUM> is constituted by a plurality of arc portions 31f and a plurality of flat portions <NUM>. Each of the plurality of arc portions 31f has an arc-shaped outline of its cross section perpendicular to the axial direction, and each of the plurality of flat portions <NUM> has a linear outline of its cross section perpendicular to the axial direction. The plurality of arc portions 31f and the plurality of flat portions <NUM> are arranged alternately in the circumferential direction so as to be adjacent to each other. In the embodiment, four flat portions <NUM> are formed separately in the circumferential direction. Any two of the four flat portions <NUM> facing each other in the radial direction across the central axis C1 are arranged parallel to each other. Further, any two of the four flat portions <NUM> adjacent to each other in the circumferential direction are perpendicular to each other. The flat portions <NUM> are located at the portions of the case <NUM> opened by case cutting.

Of the four flat portions <NUM>, each of a pair of flat portions <NUM> that are opposed to each other in the radial direction has an extension portion <NUM> that extends in the radial direction. The extension portions <NUM> are formed to project in opposite radial directions. The elastic deformation portions <NUM> are formed at the radially outer ends of the extension portions <NUM>.

Each of the elastic deformation portions <NUM> extends in the axial direction along the outer periphery of the case <NUM>. The elastic deformation portion <NUM> is shaped like a plate having a predetermined width along the circumferential direction (circumferential width). The proximal end 32a of the elastic deformation portion <NUM> is connected to the extension portion <NUM>. The elastic deformation portion <NUM> extends from the first end surface 2c of the case <NUM> across the second surface 112b of the second arm <NUM>. In other words, the proximal end 32a of the elastic deformation portion <NUM> is positioned closer to the first arm <NUM> than is the first end surface 2c in the axial direction. The distal end 32b of the elastic deformation portion <NUM> is positioned beyond the second surface 112b of the second arm <NUM>. The elastic deformation portion <NUM> is formed of an elastic material that allows deformation in which the distal end 32b is slightly moved in the radial direction with the proximal end 32a serving as the base point.

At the distal end 32b of the elastic deformation portion <NUM>, there is formed the claw portion <NUM> projecting radially outward. The circumferential width of the claw portion <NUM> is equal to the circumferential width of the elastic deformation portion <NUM>. The claw portion <NUM> has a sloping surface 33a that is inclined to increase the thickness from the distal end 32b toward the proximal end. The claw portions <NUM> (and the elastic deformation portions <NUM>) are formed at positions opposed to each other in the radial direction across the central axis C1. In this embodiment, the elastic deformation portion <NUM> shaped like a plate and having a predetermined thickness has an end portion that is bent twice to form the claw portion <NUM>, but this is not limitative. The distance between the claw portions <NUM> in the radial direction is larger than the distance between two locking grooves <NUM> (described later) that are arranged symmetrically with respect to the central axis C1.

The coupling member <NUM> is placed from the second carrier <NUM> side onto the case <NUM> fitted into the through hole (through portion) 112d formed in the second arm <NUM>, in such a manner that the ring portion <NUM> covers the first end surface 2c of the case <NUM>. At this time, the arc portions 31f contact with the first end surface 4a of the outer flange portion <NUM>. The outer flange portion <NUM> is formed by case cutting not to correspond to the flat portions <NUM> in the circumferential direction, but to correspond to the arc portions 31f in the circumferential direction.

The second arm <NUM> has the through hole 112d extending through the second arm <NUM> in the thickness direction of the second arm <NUM> (the axial direction). The case <NUM> is fitted into the through hole 112d of the second arm <NUM>. The through hole 112d has approximately the same diameter and inner surface shape as the case <NUM> fitted therein. The through hole 112d is in contact with the outer periphery 2a of the case <NUM>, except for the portions corresponding to the locking grooves (through portion) <NUM> (described later).

The inner diameter of the through hole 112d preferably decreases toward the direction in which the case <NUM> is inserted. Specifically, the inner diameter of the through hole 112d preferably gradually decreases along the axial direction from the first surface 112a toward the second surface 112b. In this embodiment, a tapered surface is formed on the inner side of the through hole 112d so as to approach the central axis C1 from the proximal end 32a toward the distal end 32b of the elastic deformation portion <NUM>. The outer periphery 2a of the case <NUM> is also shaped in conformity to the tapered or other decreased diameter shape of the through hole 112d. This prevents looseness between the second arm <NUM> and the case <NUM>.

The case <NUM> is fitted into the through hole 112d of the second arm <NUM>. The inner periphery of the through hole 112d has a noncircular shape corresponding to the outer periphery of the ring portion <NUM>. Accordingly, the inner periphery of the through hole 112d is constituted by four arc portions 112f and four flat portions <NUM>. Each of the four arc portions 112f has an arc-shaped outline of its cross section perpendicular to the axial direction, and each of the four flat portions <NUM> has a linear outline of its cross section perpendicular to the axial direction. Of the four flat portions <NUM>, each of a pair of flat portions <NUM> that are opposed to each other in the radial direction has a locking groove <NUM> that corresponds to the extension portion <NUM> and the elastic deformation portion <NUM>. The coupling member <NUM> and the locking groove <NUM> of the second arm <NUM> constitute a coupling portion.

The outer periphery 2a of the case <NUM> has a surface shape corresponding to the through hole 112d of the second arm <NUM>. Specifically, the outer periphery 2a of the case <NUM> has a noncircular shape corresponding to the outer periphery of the ring portion <NUM>. The outer periphery 2a of the case <NUM> is constituted by four arc portions 2f and four flat portions <NUM>. Each of the four arc portions 2f has an arc-shaped outline of its cross section perpendicular to the axial direction, and each of the four flat portions <NUM> has a linear outline of its cross section perpendicular to the axial direction.

The case <NUM> is fitted into the through hole 112d of the second arm <NUM> so as to protrude inward in the radial direction. This prevents the case <NUM> from rotating in the circumferential direction relative to the through hole 112d. In other words, the flat portions <NUM> and <NUM> constitute an anti-rotation portion that prevents the case <NUM> from rotating in the circumferential direction relative to the through hole 112d.

When setting up the coupling member <NUM>, the elastic deformation portion <NUM> is inserted into the locking groove <NUM> from the second carrier <NUM> side toward the case <NUM> fitted into the through hole 112d of the second arm <NUM>. The claw portion <NUM> abuts against the inner surface of the locking groove <NUM>, causing the elastic deformation portion <NUM> to elastically deform so that the distal end 32b moves radially inward with the proximal end 32a serving as the base point. As the elastic deformation portion <NUM> is inserted further into the locking groove <NUM>, the claw portion <NUM> passes through the locking groove <NUM> and reaches the outside of the locking groove <NUM> in the axial direction, beyond the second surface 112b of the second arm <NUM>. Thus, the claw portion <NUM> detaches from the inner surface of the locking groove <NUM>, and the elastic deformation portion <NUM> is elastically deformed so that the distal end 32b moves radially outward with the proximal end 32a serving as the base point. At this time, a contact surface 32d of the elastic deformation portion <NUM> contacts with an inner surface 112h1 of the locking groove <NUM>.

As a result, the elastic deformation portion <NUM> is fixed to the locking groove <NUM> by the snap-fit structure using the elastic restorative deformation of the elastic deformation portion <NUM>. On the second surface 112b of the second arm <NUM>, the claw portion <NUM> abuts against the periphery of the through hole 112d. The coupling member <NUM> is thus retained to the second arm <NUM>. Further, the holding surface 31a of the ring portion <NUM> abuts against the first end surface 2c of the case <NUM> and the first end surface 4a of the outer flange portion <NUM>. Since the holding surface 31a of the ring portion <NUM> covers the first end surface 2c of the case <NUM> and the first end surface 4a of the outer flange portion <NUM>, the case <NUM> is retained to the through hole 112d. On the first surface 112a of the second arm <NUM>, the second end surface 4b of the outer flange portion <NUM> abuts against the periphery of the through hole 112d. The case <NUM> is thus retained to the through hole 112d. When setting up the coupling member <NUM>, the coupling member <NUM> and the case <NUM> can be fitted together into the through hole 112d of the second arm <NUM>.

Next, the operation and action of the third speed reducing mechanism 1C will be described. The third servomotor <NUM> shown in <FIG> is driven to rotate the input crankshaft <NUM> shown in <FIG>. With the rotation of the crankshaft <NUM>, the oscillating gears <NUM> and <NUM> rotatably supported by the eccentric portions 21a and 21b are oscillatorily rotated. A part of the external teeth 23a and 23b of the oscillating gears <NUM> and <NUM> then mesh with the internal tooth pins <NUM> of the case <NUM>.

The number of teeth for each of the external teeth 23a and 23b is smaller than the number of the internal tooth pins <NUM> by, for example, one. Therefore, the meshing positions of the external teeth 23a and 23b with the internal tooth pins <NUM> (case <NUM>) are shifted sequentially in the circumferential direction. Thus, the oscillating gears <NUM> and <NUM> rotate. The rotation of the oscillating gears <NUM> and <NUM> is at a lower speed than the rotation of the input crankshaft <NUM>.

The output shafts <NUM> are inserted into the output shaft insertion holes 25a and 25b. When the oscillating gears <NUM> and <NUM> rotate, the rotational force of the oscillating gears <NUM> and <NUM> in the rotational direction is transmitted to the output shafts <NUM>. Each of the output shaft <NUM> is rotatably supported by the carriers <NUM> and <NUM>. Thus, the rotational force of the oscillating gears <NUM> and <NUM> is transmitted to the carriers <NUM> and <NUM>.

The outer peripheral surfaces of the carriers <NUM> and <NUM> are slidably fitted to the large-diameter portions 3a and 3b of the case <NUM>, respectively. Thus, each of the carriers <NUM> and <NUM> is rotated relative to the case <NUM>. That is, the rotation of the third servomotor <NUM> is decelerated and outputted to the carrier <NUM> (the first carrier <NUM> and second carrier <NUM>). The second arm <NUM> is fixed to the case <NUM>. The first arm <NUM> is fixed to the second carrier <NUM>. Thus, the first arm <NUM> is rotated around the third rotation axis L3 relative to the second arm <NUM>.

For example, when the rotation of the first arm <NUM> (the second carrier <NUM>) is restricted, the rotation of the third servomotor <NUM> is decelerated and outputted to the case <NUM>. In this case, the second arm <NUM> is rotated relative to the first arm <NUM> about the third rotation axis L3. That is, the speed reducing mechanism 1C restricts the rotation of either the case <NUM> or the carrier <NUM>, so that the other of the case <NUM> and the carrier <NUM> serves as the output for the servomotor <NUM>. This operation principle also applies to the first speed reducing mechanism 1A and the second speed reducing mechanism 1B.

The output shaft <NUM> and the carriers <NUM> and <NUM> are integrated by inserting the output shaft <NUM> into the output shaft holes 13b and 14b. Thus, the output shaft <NUM> is freely rotated relative to the carriers <NUM> and <NUM>. Moreover, by forming the carriers <NUM> and <NUM> of resin, the output shaft <NUM> can be rotatably supported by the carriers <NUM> and <NUM> without providing bearings separately from the carriers <NUM> and <NUM>. The oscillating gears <NUM> and <NUM> are made of resin.

The output shaft <NUM> is smoothly brought into contact with the oscillating gears <NUM> and <NUM> without providing bearings separately from the oscillating gears <NUM> and <NUM>. The PV limit of each carrier <NUM> and <NUM> and each oscillating gear <NUM> and <NUM> can be increased. Therefore, the speed reducing mechanisms 1A, 1B, and 1C can be stably operated, which extends the product life. Since it is not necessary to provide bearings for the contact between the carriers <NUM> and <NUM> and the output shaft <NUM> and between the oscillating gears <NUM> and <NUM> and the output shaft <NUM>, the speed reducing mechanisms 1A, 1B and 1C can have a smaller size.

The output shaft <NUM> is inserted into the output shaft holes 13b and 14b of the carriers <NUM> and <NUM>, respectively. Therefore, compared to the case where the output shaft <NUM> is press-fitted into the carriers <NUM> and <NUM> and fixed therein, the work efficiency in assembling and disassembling the speed reducing mechanisms 1A, 1B and 1C can be improved. The carriers <NUM> and <NUM> and the oscillating gears <NUM> and <NUM> are formed of resin, such that they can have a smaller weight. On the other hand, the output shaft <NUM> is formed of metal, and thus the rigidity of the output shaft <NUM> can be increased. Therefore, the speed reducing mechanisms 1A, 1B, and 1C can be operated more stably, and the product life can be extended.

In the eccentric oscillation speed reducing mechanisms (rotation mechanisms 1A, 1B, 1C), the carriers <NUM> and <NUM> having the output shaft holes 13b and 14b and the oscillating gears <NUM> and <NUM> having the output shaft insertion holes 25a and 25b are used as described above. As a result, the drive efficiency can be improved while downsizing the speed reducing mechanisms 1A, 1B, and 1C. Moreover, the PV limit of each carrier <NUM>, <NUM> and each oscillating gear <NUM>, <NUM> can be easily increased, and the rigidity of the output shaft <NUM> can also be increased. Therefore, the speed reducing mechanisms 1A, 1B, and 1C can be stably operated. The product life of the speed reducing mechanisms 1A, 1B, and 1C can be extended.

The elastic shim <NUM> and the spacer <NUM> are attached to the first end portion 9a of the output shaft <NUM>. Therefore, positioning of the output shaft <NUM> relative to the carriers <NUM> and <NUM> can be performed easily and accurately. The elastic shim <NUM> and the spacer <NUM> can absorb manufacturing errors of the case <NUM>, the carriers <NUM> and <NUM>, and the output shaft <NUM>. The elastic shim <NUM> and the spacer <NUM> help positional adjustment of the output shaft <NUM> relative to the carriers <NUM> and <NUM>.

The two members (the elastic shim <NUM> and the spacer <NUM>) are used for adjusting the position of the output shaft <NUM>. Thus, it is possible to increase the variety of positional adjustment methods by combining these two members. Therefore, it is possible to more easily and accurately position the output shaft <NUM> relative to the carriers <NUM> and <NUM>, and to reduce looseness of the output shaft <NUM>.

In particular, the elastic shim <NUM> may be attached so as to be compressed and deformed slightly in the axial direction, such that the elastic restoring force produced in the elastic shim <NUM> can bias the first carrier <NUM> toward the second carrier <NUM>. This securely prevents looseness of the carriers <NUM> and <NUM> and the output shaft <NUM>. Even if the looseness of the output shaft <NUM> in the axial direction relative to the carriers <NUM> and <NUM> increases due to aged deterioration or the like, this looseness can be absorbed by the elastic shim <NUM>. By biasing the first carrier <NUM> toward the second carrier <NUM>, a preload can be applied to the bearings 15a and 15b disposed in the input shaft holes 13a and 14a of the carriers <NUM> and <NUM>, respectively.

The speed reducing mechanisms 1A, 1B, and 1C as described above can be used for the joint portions 106a, 106b, and 106c, respectively, of the cooperative robot <NUM>, such that the operation of the cooperative robot <NUM> can be stabilized. The speed reducing mechanisms 1A, 1B, and 1C as described above can be used for the joint portions 106a, 106b, and 106c, respectively, of the cooperative robot <NUM>, such that the product life of the cooperative robot <NUM> can be extended.

In the above first embodiment, the elastic shim <NUM> and the spacer <NUM> are provided on the first end portion 9a of the output shaft <NUM>. However, the configuration is not limited to this. The elastic shim <NUM> and the spacer <NUM> may be provided on the second end portion 9b of the output shaft <NUM>. Further, it is also possible that the elastic shims <NUM> and the spacers <NUM> are provided on both end portions 9a and 9b of the output shaft <NUM>. In addition, it is also possible that either one of the elastic shim <NUM> and the spacer <NUM> is provided.

In the first embodiment, the outer flange portion <NUM> is sandwiched between the second arm <NUM> and the ring portion <NUM> of the coupling member <NUM> to axially fix the case <NUM> fitted into the through hole 112d. The case <NUM> is fitted into the through hole 112d and the flat portions <NUM> of the anti-rotation portion are contacted with the flat portions <NUM>, so as to prevent the case <NUM> from rotating in the circumferential direction relative to the second arm <NUM>. Therefore, when the speed reducing mechanism 1C is assembled to the second arm <NUM>, to which the decelerated output of the speed reducing mechanism 1C is transmitted, there is no need to use bolts or other fasteners. Specifically, the assembly process can be completed by simply hooking the claw portion <NUM>, which is a snap-fit structure, to the periphery of the second surface 112b. This reduces steps of the work process required for fastening by multiple bolts and eliminates work time. Since bolts and other fasteners are not used, there is no need to consider the strength of fastening when reducing the size or changing materials to resin for downsizing and weight reduction. Therefore, there is no need to form holes or other openings necessary for bolting in the outer flange portion <NUM> and the second arm <NUM>. This can also reduce the steps of the work process.

In the first embodiment, the outer flange portion <NUM> is sandwiched between the second arm <NUM> and the coupling member <NUM> on both sides, so as to axially fix the case <NUM> fitted into the through hole 112d. The case <NUM> is fitted into the through hole 112d and the flat portions <NUM> of the anti-rotation portion are contacted with the flat portions <NUM>, so as to prevent the case <NUM> from rotating in the circumferential direction relative to the second arm <NUM>. The anti-rotation capacity obtained by preventing the deformation of the anti-rotation portion can be higher than the anti-rotation capacity obtained by a frictional force produced by fastening with bolts. This enables larger torque transmission.

In the first embodiment, the coupling member <NUM> and the case <NUM> are separate components, but these members can be integrated. Specifically, the coupling member <NUM> with its holding surface 31a in contact with the first end surface 2c can be formed integrally with the case <NUM> without changing the shapes thereof. In other words, the elastic deformation portion <NUM> having the claw portion <NUM> at the distal end 32b may be formed integrally with the case <NUM>. In this case, the outer flange portion <NUM> does not need to be held by the ring portion <NUM>, and thus the proximal end 32a of the elastic deformation portion <NUM> can be positioned near the second end surface 4b of the outer flange portion <NUM> in the axial direction. In this case, it is preferable to mold the coupling member <NUM> and the case <NUM> with resin.

By the way, wave gears are sometimes preferred in precision apparatuses using small speed reducers, for the advantage of light weight. However, wave gears can cause ratcheting due to overloading or the like. Therefore, there is a need for a compact and lightweight eccentric oscillating speed reducer to replace the wave gears. If resin or other materials are used to reduce the size and weight of an eccentric oscillating speed reducer, the threaded portion, which is the connection with the mating member, may fail to have enough strength to withstand. In other words, in a rotation mechanism (including oscillating speed reducers) that uses resin, when bolts are used in the connection with the mating member to which the torque is transmitted, the threaded holes in the resin may fail to withstand the tightening strength of the bolts. This problem is solved in the present embodiment by using a snap-fit structure for the coupling member <NUM>.

Torque is transmitted by means of circumferential irregularities that mesh with each other, as in the relationship between the flat portions <NUM> of the through hole 112d and the flat portions <NUM> of the outer periphery 2a of the case <NUM>. This enables larger torque transmission than the friction between the surfaces using the axial tension of screws. Further, the snap-fit structure using the coupling member <NUM> allows easier mounting and dismounting of the case <NUM> than with bolts.

Even if the case <NUM> and the elastic deformation portion <NUM> are integrated, a resin-made member of the output portion that outputs rotation can be fastened to the mating member, by using a snap-fit structure as the coupling member <NUM> that deforms elastically.

The following describes a second embodiment of the speed reducing mechanism according to the invention with reference to the accompanying drawings. <FIG> is a perspective view showing the rotation mechanism according to the present embodiment. The second embodiment is different from the first embodiment in terms of the coupling portion and the output portion. Except for the coupling portion and the output portion, the same reference numerals are given to elements of the second embodiment corresponding to elements of the first embodiment, and the description of these elements will not be repeated.

As shown in <FIG>, this embodiment includes the case <NUM> as the fixed portion and the carrier <NUM> as the output portion. In other words, the second arm (mating member) <NUM> is coupled to the carrier <NUM>, and the first arm <NUM> is coupled to the case <NUM>.

In the case <NUM> of this embodiment, the outer flange portion <NUM> is formed continuously over the entire circumference of the case <NUM>. The outer flange portion <NUM> has a plurality of bolt holes 4d penetrating therethrough in the axial direction and arranged at equal intervals in the circumferential direction. The outer flange portion <NUM> receives the first arm <NUM> applied thereto from the outside in the axial direction (the opposite side to the second arm <NUM>), which is the lower side in <FIG>. Bolts are inserted into the bolt holes 4d from the opposite side to the first arm <NUM>. The bolts are tightened to the internally threaded portions of the first arm <NUM>, thereby fixing the case <NUM> to the first arm <NUM>. The first arm <NUM> is not shown in <FIG>.

The carrier <NUM> is formed integrally with a coupling member <NUM> as the coupling portion. The coupling member <NUM> is formed on the surface 14c of the second carrier <NUM>. The coupling member <NUM> protrudes in the axial direction from the surface 14c of the second carrier <NUM>. The coupling member <NUM> is formed near the center of the surface 14c of the second carrier <NUM> in the radial direction. The coupling member <NUM> includes a base <NUM> formed near the center of the surface 14c in the radial direction, two elastic deformation portions <NUM> extending in the axial direction from the base <NUM>, a claw portion <NUM> formed at the distal end 132b of each of the two elastic deformation portions, and a central projection <NUM>.

The base <NUM> is formed integrally with the second carrier <NUM>. The base <NUM> projects in the axial direction from the surface 14c. The base <NUM> has a rectangular outline as viewed from the axial direction. The respective proximal ends 132a of the elastic deformation portions <NUM> are connected to the two opposed short sides of the four sides of the base <NUM>. The proximal ends 132a are each formed as a plate positioned along the short side of the base <NUM>. The distal ends 132b are each formed to be separated from the surface 14c in the axial direction. The elastic deformation portions <NUM> are formed such that the direction from the proximal ends 132a toward the distal ends 132b is perpendicular to the surface 14c.

The elastic deformation portions <NUM> are symmetrical to each other around the central axis C1. The elastic deformation portions <NUM> are parallel to each other. The elastic deformation portions <NUM> are formed along the lateral direction of the outline of the base <NUM>. The elastic deformation portions <NUM> are spaced apart from each other in the radial direction along the longitudinal direction of the outline of the base <NUM>. The central projection <NUM> is formed on a portion of the base <NUM> between the elastic deformation portions <NUM>. The mutually opposed surfaces of the elastic deformation portions <NUM> are parallel to each other along the axial direction. At the distal ends 132b of the elastic deformation portions <NUM>, there are formed the claw portions <NUM> projecting in the radial direction.

The claw portions <NUM> are formed on the elastic deformation portions <NUM> so as to project outward in the opposite radial directions. The claw portions <NUM> project outward from the outline of the base <NUM> as viewed along the axial direction. Each of the claw portions <NUM> is formed so that the amount of projection in the radially outward direction increases from the distal end 132b toward the proximal end 132a. In other words, the amount of projection of the claw portion <NUM> is largest at the position spaced by a predetermined distance from the distal end 132b toward the proximal end 132a. The claw portion <NUM> has a sloping surface 133a that is inclined to increase the thickness from the distal end 132b toward the proximal end 132a.

The outermost diameter between the elastic deformation portions <NUM>, or the distance between the sloping surfaces 133a along the longitudinal direction of the outline of the base <NUM>, increases from the distal ends 132b toward the proximal ends 132a along the sloping surfaces 133a. The distance between the contact surfaces 132d of the elastic deformation portions <NUM> along the longitudinal direction of the outline of the base <NUM> is constant over the range from the claw portions <NUM> to the proximal ends 132a.

Thus, the outermost diameter between the elastic deformation portions <NUM> corresponds to the distance between the sloping surfaces 133a along the longitudinal direction of the outline of the base <NUM>. The elastic deformation portions <NUM> can be elastically deformed to the extent that the outermost diameter between the claw portions <NUM> changes. The elastic deformation portions <NUM> are hardly elastically deformed in a direction perpendicular to the projecting direction of the claw portions <NUM> along the surface 14c.

As viewed from the axial direction, the central projection <NUM> does not project outward beyond the outline of the base <NUM> (toward the surface 14c). As viewed from the axial direction, the central projection <NUM> extends over the entire lateral length of the outline of the base <NUM>. The central projection <NUM> has the same length as one side of the outline of the base <NUM> in the lateral direction. The central projection <NUM> has a length in the longitudinal direction of the outline of the base <NUM> that is shorter than the distance between the proximal ends 132a of the elastic deformation portions <NUM>. In other words, the central projection <NUM> is radially separated from each of the elastic deformation portions <NUM> in the longitudinal direction of the outline of the base <NUM>.

The central projection <NUM> is hardly elastically deformable in the lateral direction of the outline of the base <NUM>, which direction is perpendicular to the projecting direction of the claw portions <NUM> along the surface 14c. The side surfaces 134d of the central projection <NUM> are planes extending along the longitudinal direction of the outline of the base <NUM>. The side surfaces 134d are spaced apart by a distance equal to the lateral length of the outline of the base <NUM>.

The second arm <NUM> has a through hole (through portion) <NUM> extending through the second arm <NUM> in the thickness direction thereof. The through hole <NUM> corresponds to the through hole 112d in the first embodiment. The coupling member <NUM> is fitted in the through hole <NUM>. As viewed from the axial direction, the through hole <NUM> has approximately the same outline as the base <NUM> of the coupling member <NUM> fitted therein. In other words, as viewed from the axial direction, the through hole <NUM> has a rectangular outline and is open to the first surface 112a and the second surface 112b of the second arm <NUM>. The outline of the opening in the first surface 112a and the outline of the opening in the second surface 112b of the second arm <NUM> are formed in the same shape and provided at the same position in the axial direction.

The inner periphery of the through hole <NUM> is in contact with the outer periphery of the base <NUM> of the coupling member <NUM> fitted in the through hole <NUM>. In the inner periphery of the through hole <NUM>, the entire periphery of the opening close to the second surface 112b is in contact with the outer periphery of the base <NUM>. In particular, the inner periphery of the through hole <NUM> is in contact with the side surfaces 134d of the central projection <NUM> and the side surfaces 132e of the elastic deformation portions <NUM>. Further, the inner periphery of the through hole <NUM> is in contact with the contact surfaces 132d of the elastic deformation portions <NUM>.

After assembly, the coupling member <NUM> extends through the through hole <NUM>. The second surface 112b of the second arm <NUM> is in contact with the surface 14c of the second carrier <NUM>. The second surface 112b of the second arm <NUM> is not in contact with the first end surface 2c of the case <NUM>. The elastic deformation portions <NUM> extend in the axial direction from the second surface 112b of the second arm <NUM> beyond the first surface 112a of the second arm <NUM>.

In this embodiment, the anti-rotation portion includes the contact surfaces 132d, the side surfaces 134d, and the side surface 132e of the coupling member <NUM>. Also, the anti-rotation portion includes the through hole <NUM> of the second arm <NUM>.

When assembling the coupling member <NUM> and the second arm <NUM> to each other, the coupling member <NUM> and the second arm <NUM> are brought close to each other in the axial direction so that the second surface 112b remains perpendicular to the axial direction. At this time, the sides of the inner periphery of the through hole <NUM> along the lateral direction are aligned with the elastic deformation portions <NUM> as viewed from the axial direction, and the sides of the inner periphery of the through hole <NUM> along the longitudinal direction are aligned with the side surfaces 134d as viewed from the axial direction.

With this position maintained, the elastic deformation portions <NUM> are inserted into the through hole <NUM> of the second arm <NUM>. The claw portions <NUM> abut against the inner surface of the through hole <NUM>, causing the elastic deformation portions <NUM> to elastically deform so as to bend inward in the longitudinal direction of the outline of the base <NUM>. In other words, the projecting shape of the claw portions <NUM> causes the elastic deformation portions <NUM> to elastically deform in the directions in which the distal ends 132b move closer to each other.

When the elastic deformation portions <NUM> are inserted into the through hole <NUM>, the claw portions <NUM> pass through the through hole <NUM> and reach the outside of the through hole <NUM> in the axial direction, beyond the first surface 112a of the second arm <NUM>. Thus, the claw portions <NUM> no longer abut against the inner surface of the through hole <NUM>, causing the elastic restorative deformation of the elastic deformation portions <NUM> in which the elastic deformation portions <NUM> straighten outward in the longitudinal direction of the outline of the base <NUM> to return to the positions taken before the insertion. The inner surface of the through hole <NUM> contacts with the contact surfaces 132d of the elastic deformation portions <NUM> adjacent to the claw portions <NUM>. At the same time, the second surface 112b of the second arm <NUM> contacts with the surface 14c of the second carrier <NUM>. The contact area between the second surface 112b of the second arm <NUM> and the surface 14c of the second carrier <NUM> is as large as possible. This arrangement sets and defines the direction of fixation of the second arm <NUM> to the second carrier <NUM>.

As a result, the elastic deformation portions <NUM> are fixed to the through hole <NUM> by the snap-fit structure using the elastic restorative deformation of the elastic deformation portions <NUM>. On the first surface 112a of the second arm <NUM>, the claw portions <NUM> abut against the periphery of the through hole <NUM>. This allows the coupling member <NUM> to be retained to the second arm <NUM>. In other words, the second arm <NUM> and the second carrier <NUM> can be retained to each other.

Further, the side surfaces 134d of the central projection <NUM> and the side surfaces 132e of the elastic deformation portions <NUM> contact with the inner surface of the through hole <NUM> in the lateral direction of the outline of the base <NUM>. Further, the contact surfaces 132d of the elastic deformation portions <NUM> contact with the inner surface of the through hole <NUM> in the longitudinal direction of the outline of the base <NUM>.

In the axial direction along the central axis C1, all the contactable surfaces of the outer periphery of the coupling member <NUM>, including the outline of the base <NUM>, positioned on the second surface 112b side of the claw portions <NUM> and the first surface 112a of the second arm <NUM> are in contact with the inner surface of the through hole <NUM>. In other words, all the contactable surfaces of the outer periphery of the coupling member <NUM> are in contact with the inner surface of the through hole <NUM> for the entire length in the thickness direction of the second arm <NUM>. This prevents the rotation between the second arm <NUM> and the carrier <NUM> by the action of the anti-rotation portion.

In the second embodiment, the carrier <NUM> and the coupling member <NUM> are formed of resin, and at the same time, the carrier <NUM> and the coupling member <NUM> are integrated. This produces the effect of providing a rotation mechanism and a robot that can have a small size and weight using resin and have an improved assembly and disassembly work efficiency. At the same time, since the case <NUM> does not have to be made of resin, it does not lack the necessary strength for bolting or the like.

The following describes a speed reducing mechanism according to a third embodiment of the invention with reference to the accompanying drawings. <FIG> schematically illustrates a speed reducing mechanism <NUM> according to the third embodiment. The third embodiment is different from the first and second embodiments in terms of the elastic shim. Except for the elastic shim, the same reference numerals are given to elements of the third embodiment corresponding to elements of the first and second embodiments, and the description of these elements will not be repeated.

The difference between the third embodiment and the first and second embodiments is that the elastic shim <NUM> is provided on the first end portion 9a side of the output shaft <NUM> in the first embodiment, whereas the elastic shim <NUM> is not provided in the third embodiment. As shown in <FIG>, the shim receiving recess <NUM> (see <FIG>) is not formed in the surface 13c of the first carrier <NUM>. Therefore, the entire surface 13c of the first carrier <NUM> is flat. Only the spacer <NUM> is provided on the first end portion 9a of the output shaft <NUM>. The speed reducing mechanism <NUM> thus configured also produces the same effect as in the first embodiment.

The following describes a fourth embodiment of the speed reducing mechanism according to the invention with reference to the accompanying drawings. <FIG> is an exploded perspective view showing the rotation mechanism according to the fourth embodiment. The fourth embodiment is different from the above-described second embodiment in terms of the coupling portion and the output portion. Except for the coupling portion and the output portion, the same reference numerals are given to elements of the fourth embodiment corresponding to elements of the second embodiment, and the description of these elements will not be repeated.

In the case <NUM> of this embodiment, the outer flange portion <NUM> is formed continuously over the entire circumference of the case <NUM>. The outer flange portion <NUM> has a plurality of bolt holes 4d penetrating therethrough in the axial direction and arranged at equal intervals in the circumferential direction. The outer flange portion <NUM> receives the first arm <NUM> applied thereto from the outside in the axial direction (the opposite side to the second arm <NUM>), which is the lower side in <FIG>. Bolts are inserted into the bolt holes 4d from the side of the outer flange portion <NUM> opposite to the first arm <NUM>. The bolts are tightened to the internally threaded portions of the first arm <NUM>, thereby fixing the case <NUM> to the first arm <NUM>. The first arm <NUM> is not shown in <FIG>.

The carrier <NUM> is formed integrally with a coupling member <NUM> as the coupling portion. The coupling member <NUM> is formed on the surface 14c of the second carrier <NUM>. The coupling member <NUM> protrudes in the axial direction from the surface 14c of the second carrier <NUM>. The coupling member <NUM> is formed near the center of the surface 14c of the second carrier <NUM> in the radial direction. Unlike the coupling member <NUM> of the second embodiment, the coupling member <NUM> does not include a base <NUM> (see <FIG>) formed near the center of the surface 14c in the radial direction. The coupling member <NUM> includes two elastic deformation portions <NUM> extending in the axial direction from the surface 14c of the second carrier <NUM>, claw portions <NUM> formed at the distal ends 142b of the two elastic deformation portions, and two projections <NUM> provided on the surface 14c of the carrier <NUM> and positioned outside the second arm (mating member) <NUM>.

As with the elastic deformation portions <NUM> in the second embodiment, the elastic deformation portions <NUM> are formed integrally with the second carrier <NUM>. As with the elastic deformation portions <NUM> in the second embodiment, the elastic deformation portions <NUM> project from the surface 14c in the axial direction. The elastic deformation portions <NUM> are provided at the same positions as the elastic deformation portions <NUM> in the second embodiment, as viewed from the axial direction. The proximal ends 142a of the elastic deformation portions <NUM> are shaped like a plate and connected to the surface 14c of the second carrier <NUM>. The distal ends 142b of the elastic deformation portions <NUM> are separated from the surface 14c in the axial direction. The elastic deformation portions <NUM> are formed such that the direction from the proximal ends 142a toward the distal ends 142b is perpendicular to the surface 14c.

The elastic deformation portions <NUM> are symmetrical to each other around the central axis C1. The elastic deformation portions <NUM> are parallel to each other. The elastic deformation portions <NUM> are formed in the same manner as the elastic deformation portions <NUM>. The proximal ends 142a of the elastic deformation portions <NUM> are formed to be planes parallel to each other. At the distal ends 142b of the elastic deformation portions <NUM>, there are formed claw portions <NUM> projecting in the radial directions so as to be opposed to each other.

The claw portions <NUM> are formed so as to project radially inward. In the second embodiment, as viewed from the axial direction, the claw portions <NUM> project outside of the outline of the base <NUM> from the elastic deformation portions <NUM> extending along the lateral direction of the outline of the base <NUM>. In this respect, the claw portions <NUM> of the present embodiment are different.

Each of the claw portions <NUM> is formed so that the amount of projection in the radially inward direction increases from the distal end 142b toward the proximal end 142a. In other words, the amount of projection of the claw portion <NUM> is largest at the position spaced by a predetermined distance from the distal end 142b toward the proximal end 142a. The claw portion <NUM> has a sloping surface 143a that is inclined to increase the thickness from the distal end 142b toward the proximal end 142a.

The distance between the elastic deformation portions <NUM> decreases along the sloping surfaces 143a from the distal ends 142b toward the proximal ends 142a. Further, the distance between the elastic deformation portions <NUM> is constant beyond the claw portions <NUM> to the proximal ends 142a. The contact surfaces 142e positioned perpendicular to the direction in which the claw portions <NUM> of the elastic deformation portions <NUM> are opposed are flush with each other.

The distance between the elastic deformation portions <NUM> is the distance between the sloping surfaces 143a in the radial direction and the distance between the contact surfaces 142d in the radial direction. The elastic deformation portions <NUM> can be elastically deformed to the extent that the distance between the claw portions <NUM> changes. The elastic deformation portions <NUM> are hardly elastically deformable in a direction perpendicular to the projecting direction of the claw portions <NUM> along the surface 14c.

The projections <NUM> are formed on both sides of the second arm (mating member) <NUM>, as viewed from the axial direction. The projections <NUM> are opposed to the contact surfaces 142e, as viewed from the axial direction. The projections <NUM> extend longer than and in the same direction as the distance between the elastic deformation portions <NUM>, as viewed from the axial direction. The projections <NUM> project from the surface 14c in the same direction as the elastic deformation portions <NUM>.

The projections <NUM> has a surface facing radially outward that is shaped like an arc having the same outline as the surface 14c of the second carrier <NUM>. The projections <NUM> has a surface facing radially inward that is contacted by the side surfaces 112c of the second arm (mating member) <NUM>. The projections <NUM> are spaced apart from the two elastic deformation portions in the radial direction, as viewed from the axial direction.

The projections <NUM> are hardly elastically deformable in a direction perpendicular to the projecting direction of the claw portions <NUM> along the surface 14c. The side surfaces 145d of the projections <NUM> have a planar shape extending along the longitudinal side surfaces 112c of the second arm (mating member) <NUM> and in parallel to the contact surfaces 142e.

The second arm <NUM> has two through holes (through portions) 112n extending through the second arm <NUM> in the thickness direction thereof. The through holes 112n correspond to the through hole <NUM> in the second embodiment. As viewed from the axial direction, the two through holes 112n are spaced apart in the projecting direction of the claw portions <NUM> (radial direction). Each of the through holes 112n has a rectangular outline, as viewed from the axial direction. Each of the through holes 112n is open to the first surface 112a and the second surface 112b of the second arm <NUM>. The opening outline of the through holes 112n open to the first surface 112a and the opening outline of the through holes 112n open to the second surface 112b are formed in the same shape as viewed from the axial direction and are provided at the same position in the axial direction.

The through holes 112n receive the corresponding elastic deformation portions <NUM> fitted therein. As viewed from the axial direction, the through holes 112n have an outline that is slightly larger than the outline of the elastic deformation portions <NUM> fitted therein. As viewed from the axial direction, the through holes 112n have an outline with approximately the same dimension as the outline of the elastic deformation portions <NUM> fitted therein, in a direction perpendicular to the projecting direction of the claw portions <NUM>. As viewed from the axial direction, the through holes 112n have an outline that is in contact with the contact surfaces 142e.

As viewed from the axial direction, the through holes 112n have an outline larger than the opposed proximal ends 142a of the elastic deformation portions <NUM> fitted therein, in the direction opposite to the projecting direction of the claw portions <NUM>. As viewed from the axial direction, the through holes 112n have an outline that is approximately the same as the outline of the proximal ends 142a of the elastic deformation portions <NUM> fitted therein, in the projecting direction of the claw portions <NUM>.

In other words, the distance between the inner peripheries of the through holes 112n is the same as the distance between the contact surfaces 142d of the opposed proximal ends 142a of the elastic deformation portions <NUM>, in the projecting direction of the claw portions <NUM>. The distance between the inner peripheries of the through holes 112n on the side opposite to the projecting direction of the claw portions <NUM> is larger than the distance between the outer surfaces of the distal ends 142b of the elastic deformation portions <NUM>.

The inner peripheries of the through holes 112n are in contact with the contact surfaces 142d and the contact surfaces 142e of the elastic deformation portions <NUM> of the coupling member <NUM> fitted in the through holes 112n. In the inner peripheries of the through holes 112n, the peripheries of the openings close to the second surface 112b are in contact with the contact surfaces 142d.

The elastic deformation portions <NUM> penetrate through the corresponding through holes 112n. At this time, the second surface 112b of the second arm <NUM> contacts with the surface 14c of the carrier <NUM>. The second surface 112b of the second arm <NUM> is not in contact with the first end surface 2c of the case <NUM>. The elastic deformation portions <NUM> extend in the axial direction from the second surface 112b of the second arm <NUM> beyond the first surface 112a of the second arm <NUM>.

Both side surfaces 112c of the second arm (mating member) <NUM> are in contact with the entire length of the side surfaces 145d of the projections <NUM>. The side surfaces 145d of the two projections <NUM> are in contact with both side surfaces 112c of the second arm <NUM>. Thus, when the coupling member <NUM> is assembled, the second arm <NUM> is sandwiched between the two projections <NUM>.

In this embodiment, the anti-rotation portion includes the contact surfaces 142d and the contact surfaces 142e of the elastic deformation portions <NUM> and the side surfaces 145d of the projections <NUM>. Also, the anti-rotation portion includes the through holes 112n and the both side surfaces 112c of the second arm <NUM>.

When assembling the coupling member <NUM> and the second arm <NUM> to each other, the coupling member <NUM> and the second arm <NUM> are brought close to each other in the axial direction so that the second surface 112b remains perpendicular to the axial direction. At this time, the two through holes 112n are aligned with the elastic deformation portions <NUM> as viewed from the axial direction, and the both side surfaces 112c of the second arm <NUM> are aligned with the side surfaces 145d of the projections <NUM> as viewed from the axial direction. In <FIG>, the dotted lines indicate the direction in which the coupling member <NUM> and the second arm <NUM> are brought close to each other for assembly.

With this position maintained, the elastic deformation portions <NUM> are inserted into the through holes 112n of the second arm <NUM>. The claw portions <NUM> then abuts against the inner surfaces of the two through holes 112n. Thus, the elastic deformation portions <NUM> are elastically deformed so that the distal ends 142b move away from each other with the proximal ends 142a serving as the base points. In other words, the projecting shape of the claw portions <NUM> causes the elastic deformation portions <NUM> to elastically deform in the directions in which the distal ends 142b move away from each other. At this time, the through holes 112n of the second arm <NUM> contacts with the contact surfaces 142e.

When the elastic deformation portions <NUM> are further inserted into the through holes 112n, the claw portions <NUM> pass through the through holes 112n and reach the outside beyond the first surface 112a of the second arm <NUM>. The claw portions <NUM> then no longer abut against the inner surfaces of the through holes 112n. Accordingly, the elastic deformation portions <NUM> undergo the elastic restorative deformation in which the distal ends 142b move closer to each other with the proximal ends 142a serving as the base points, so as to return to the positions taken before the insertion. The inner surfaces of the through holes 112n contact with the contact surfaces 142d of the elastic deformation portions <NUM> adjacent to the claw portions <NUM>.

Simultaneously, the both side surfaces 112c of the second arm <NUM> contact with the side surfaces 145d of the projections <NUM>. Further, the second surface 112b of the second arm <NUM> contacts with the surface 14c of the second carrier <NUM>. The contact area between the second surface 112b of the second arm <NUM> and the surface 14c of the carrier <NUM> is as large as possible. This arrangement sets and defines the direction of fixation of the second arm <NUM> to the carrier <NUM>.

As a result, the elastic deformation portions <NUM> are fixed to the through holes 112n by the snap-fit structure using the elasticity of the elastic deformation portions <NUM>. Simultaneously, the both side surfaces 112c of the second arm <NUM> are fixed to the side surfaces 145d of the projections <NUM>. On the first surface 112a of the second arm <NUM>, the claw portions <NUM> abut against the peripheries of the through holes 112n. This allows the coupling member <NUM> to be retained to the second arm <NUM>. In other words, the second arm <NUM> and the carrier <NUM> can be retained to each other. The both side surfaces 112c of the second arm <NUM> contact with the side surfaces 145d of the projections <NUM>, and the contact surfaces 142e of the elastic deformation portions <NUM> contact with the inner surfaces of the through holes 112n. In the direction perpendicular to the contact surfaces 142e, the contact surfaces 142d of the elastic deformation portions <NUM> are in contact with the opposed inner surfaces of the through holes 112n.

As viewed from the axial direction along the central axis C1, the second arm <NUM> is sandwiched between the elastic deformation portions <NUM> and the projections <NUM> of the coupling member <NUM>. All the contactable surfaces of the coupling member <NUM> and the projection <NUM> are in contact with the second arm <NUM>. Specifically, all the contactable surfaces of the coupling member <NUM> and the projections <NUM> are in contact with the through holes 112n and the both side surfaces 112c for the entire length in the thickness direction of the second arm <NUM>. This prevents the rotation between the second arm <NUM> and the carrier <NUM> by the action of the anti-rotation portion.

In the embodiment, the carrier <NUM>, the coupling member <NUM>, and the projections <NUM> are formed of resin, and at the same time, the carrier <NUM>, the coupling member <NUM>, and the projections <NUM> are integrated. This produces the effect of providing a rotation mechanism and a robot that can have a small size and weight using resin and have an improved assembly and disassembly work efficiency. At the same time, since the case <NUM> does not have to be made of resin, it does not lack the necessary strength for bolting or the like. This embodiment produces the same advantageous effects as the second embodiment described above.

Furthermore, in this embodiment, the action of the anti-rotation portion is received only by the projections <NUM>, and the fixation between the carrier <NUM> and the coupling member <NUM> in the axial direction is accomplished by the snap-fit structure. This arrangement makes it possible to present a more secure action of the anti-rotation portion. Further, the projections <NUM> can be divided into multiple portions, as indicated by the double-dotted line in <FIG>. In this case, the plurality of projections <NUM> may all be formed along the both side surfaces 112c.

The present invention is not limited to the above embodiments but encompasses various modifications of the above embodiments not departing from the scope of the present invention, as defined by the appended claims. For example, in the coupling member <NUM> of the second embodiment, the claw portions <NUM> are configured to project in opposite directions, but they may also be formed inwardly to face each other. In addition, an anti-rotation portion is formed, in which the central projection <NUM> inside the through hole <NUM> is positioned and prevented from rotating relative to the carrier <NUM> of the second arm <NUM>, using the side surfaces 134d and the like. It is also possible that an axial projection for preventing rotation is formed on the surface 14c of the carrier <NUM> at positions on both sides of the second arm <NUM> in the lateral direction of the outline of the base <NUM>.

For example, in the above-described embodiments, the speed reducing mechanisms 1A to 1C are used in the cooperative robot <NUM> as a robot. However, this configuration is not limitative. The configurations of the above-described embodiments can be applied to various robots including, for example, two members (first member and second member) and a speed reducing mechanisms 1A to 1C disposed between the two members, the second member rotating relative to the first member.

In the above embodiments, the speed reducing mechanisms 1A to 1C have been described as an example of the gear mechanism. However, the gear mechanism is not limited to these. The configuration of the above-described embodiments can be applied to various gear mechanisms other than the speed reducing mechanisms 1A to 1C in which, for example, two gears are meshed with each other, and the rotational force is transmitted to one of the two gears, or the rotational force of this gear is transmitted to a shaft.

In the above-described embodiments, the speed reducing mechanisms 1A to 1C are what is called eccentric oscillating speed reducing mechanisms, and each speed reducing mechanism has a single center crankshaft (input crankshaft <NUM>) coaxial with the central axis C1 of the case <NUM>. However, the embodiments are not limited to this. For example, the eccentric oscillating speed reducing mechanism may be configured to oscillatorily rotate the oscillating gears <NUM> and <NUM> by rotation of two or more input crankshafts <NUM> in conjunction with each other. In this case, the input crankshafts <NUM> rotate while they revolve around the center axis C1 at the same time.

In the embodiments described above, the cooperative robot <NUM> uses the servomotors <NUM>, <NUM>, and <NUM> as drive sources. However, the drive sources are not limited to these. For example, various drive sources such as other electric motors, hydraulic motors, engines or the like may be used in place of the servomotors.

In the above embodiments, the carriers <NUM> and <NUM> are made of resin, for example. However, the carriers <NUM> and <NUM> may be made of other materials capable of reducing the size and weight.

Claim 1:
A speed reducing mechanism (1A, 1B, 1C), comprising:
a case (<NUM>) configured to output rotation to a mating member (<NUM>) from a drive source (<NUM>, <NUM>, <NUM>), which is producing a rotational force around an axis (C1);
at least one crankshaft (<NUM>) provided in the case (<NUM>) and configured to rotate by receiving the rotation of the drive source (<NUM>, <NUM>, <NUM>);
a carrier (<NUM>) provided in the case (<NUM>) and configured to decelerate rotation of the crankshaft (<NUM>);
a coupling member (<NUM>) configured to couple the mating member (<NUM>) and the case (<NUM>) by elastic deformation; and
an anti-rotation portion configured to prevent relative rotation between the mating member (<NUM>) and the case (<NUM>),
wherein
the case (<NUM>) is fitted into a through hole (112d) formed to pass through the mating member (<NUM>) in an axial direction along the axis, and an outer periphery (2a) of the case (<NUM>) is in contact with an inner surface of the through hole (112d),
the coupling member (<NUM>) includes:
an elastic deformation portion (<NUM>) extending in the axial direction along the axis (C1) and capable of elastic deformation in a radial direction intersecting the axial direction; and
a claw portion (<NUM>) provided at a distal end (32b) of the elastic deformation portion (<NUM>) and projecting in the radial direction,
the coupling member (<NUM>) couples the case (<NUM>) fitted into the through hole (112d) in the axial direction against the mating member (<NUM>),
in a state in which the coupling member (<NUM>) couples the case (<NUM>) and the mating member (<NUM>), the elastic deformation portion (<NUM>) extends through the through hole (112d) along the axial direction, and the elastic deformation portion (<NUM>) is in contact with the inner surface of the through hole (112d) by elastic deformation,
the anti-rotation portion is provided between the outer periphery (2a) of the case (<NUM>) and the inner surface of the through hole (112d), and
the case (<NUM>) is prevented from rotating relative to the through hole (112d) in a circumferential direction around the axis (C1) by the anti-rotation portion.