ARM AND ROBOT

Abstract

An arm section is composed of a first section, a second section, and a third section located between the first and second sections. The third section includes a first and a second motor. The first section comprises a first reduction mechanism, which has a first coupling gear coupled to the first motor. The second section comprises a second reduction mechanism, which has a second coupling gear coupled to the second motor. The first and third sections have a first mating surface and a second mating surface, respectively, which are cylindrical surfaces arranged coaxially with the first coupling gear or the first motor and are longitudinally mated. The second and third sections have a third mating surface and a third mating surface, respectively.A fourth mating surface is provided, which consists of cylindrical surfaces arranged coaxially with the second coupling gear or the second motor and fitted to each other longitudinally. The first and second mating surfaces and the third and fourth mating surfaces are arranged in positions offset from each other in a direction perpendicular to the longitudinal direction.

Description

Technical field The present revelation relates to an arm limb and a robot. State of the art As is known, a 6-axis articulated robot exists in the prior art, which is equipped with a first arm composed of three detachably attached sections (see, for example, patent literature 1). Both ends of the first arm are connected to a pivoting body and a second arm, and the three sections are assembled from a first arm section, a second arm section, and a third arm section, in that order starting from the side of the second arm. The second arm section houses a first motor and a second motor for driving the first arm and the second arm, respectively, and the first arm section and the third arm section each contain reduction mechanisms for reducing the speed of the motors. List of known writings Patent literature PTL 1 Publication of Japanese Patent No. 7101134 Brief description of the invention Technical problem When the first arm is assembled, the first, second, and third arm sections must be aligned with each other. To simplify this alignment step, it is desirable that the alignment can be performed without the use of an alignment tool, such as a pin. Solution to the problem According to one aspect, the present disclosure provides an arm member having a longitudinal direction and a first end part and a second end part, both of which are end parts in the longitudinal direction, wherein the first end part is connected to a first member in such a way as to be rotatable about a first axis of rotation intersecting the longitudinal direction, and wherein the second end part is connected to a second member in such a way as to be rotatable about a second axis of rotation intersecting the longitudinal direction, wherein the arm member is composed of a first section comprising the first end part, a second section comprising the second end part, and a third section arranged between the first section and the second section, and wherein the first section, the second section, and the third section are connected to each other in the longitudinal direction, the third section comprising a first motor and a second motor,which each rotate about axes parallel to the longitudinal direction, the first section comprises a first reduction mechanism that converts a rotation of the first motor into a rotation about the first axis of rotation and transmits this rotation to the first link, and the first reduction mechanism comprises a first coupling gear that is coupled to the first motor and is rotatable about an axis parallel to the longitudinal direction, the second section comprises a second reduction mechanism that converts a rotation of the second motor into a rotation about the second axis of rotation and transmits this rotation to the second link, and the second reduction mechanism comprises a second coupling gear that is coupled to the second motor and is rotatable about an axis parallel to the longitudinal direction, the first section and the third section have a first mating surface and a second mating surface, respectively.which are fitted together in the longitudinal direction, and the first mating surface and the second mating surface are cylindrical surfaces arranged coaxially with the first coupling gear or the first motor, the second section and the third section have a third mating surface and a fourth mating surface respectively, which are fitted together in the longitudinal direction, and the third mating surface and the fourth mating surface are cylindrical surfaces arranged coaxially with the second coupling gear or the second motor, and the first and second mating surfaces and the third and fourth mating surfaces are arranged in positions that are offset from each other in a direction perpendicular to the longitudinal direction. Brief description of the drawings { Fig. 1} Fig. 1 is a structural view of a robot according to an embodiment of the present disclosure. { Fig. 2} Fig. 2 is an internal structural view of a lower part and a middle part of a first arm. { Fig. 3} Fig. 3 is an internal structural view of an upper part and the middle part of the first arm. { Fig. 4A} Fig. 4A is a front view of the first arm. { Fig. 4B} Fig. 4B is a side view of the first arm. { Fig. 5A} Fig. 5A is a view to illustrate the assembly of the first arm. { Fig. 5B} Fig. 5B is a view to illustrate the assembly of the first arm. { Fig. 6} Fig. 6 is a side view of a robot equipped with a short first arm. Description of embodiments Below, an arm segment and a robot according to an embodiment of the present disclosure are described with reference to the drawings. As shown in Fig. 1, a robot 1 of this embodiment is a 6-axis vertical articulated robot. The robot 1 comprises: a base 2, which is installed on the floor surface (installation area); a pivoting body 3, which is supported to be rotatable along a vertical first axis J1 with respect to the base 2; a first arm 4, which is supported to be pivotable along a horizontal second axis J2 with respect to the pivoting body 3; a second arm 5, which is supported to be pivotable along a horizontal third axis J3, at a distal end of the first arm 4; and a three-axis wrist unit 6, which is supported at a distal end of the second arm 5. The second axis J2 and the third axis J3 are parallel to each other. Fig. 1 is a structural view of the robot 1 when viewed horizontally from the opposite side of the wrist unit 6. The arm segment of this embodiment is the first arm 4. The first arm 4 has the following: a longitudinal direction A, which runs parallel to the first axis J1; and a base end part (first end part) 4a and a distal end part (second end part) 4b, both of which are end parts in the longitudinal direction A. The base end part 4a is connected to the pivot body (first link) 3 in such a way as to be rotatable about the second axis (first axis of rotation) J2, and the distal end part 4b is connected to the second arm (second link) 5 in such a way as to be rotatable about the third axis (second axis of rotation) J3. As shown in Figs. 1, 2 to 3, the first arm 4 comprises a casing 7, two motors 8 and 9, two reduction mechanisms 10 and 11, and two bearings 12 and 13. The motors 8 and 9, the reduction mechanisms 10 and 11, and the bearings 12 and 13 are housed in the casing 7. The bearings 12 and 13 are not shown in Fig. 1. As shown in Figures 4A to 4B, the sheathing 7 is divided into three sections 71, 72, and 73 along the longitudinal direction A at two dividing surfaces P1 and P2. Accordingly, the first arm 4 is composed of a lower part (first section) 4A, an upper part (second section) 4B, and a middle part (third section) 4C, all arranged along the longitudinal direction A. Hereinafter, sections 71, 72, and 73 will also be referred to as sheathing 71, 72, and 73. The lower part 4A comprises the base end part 4a, the upper part 4B comprises the distal end part 4b, and the middle part 4C is positioned between the lower part 4A and the upper part 4B. The lower part 4A and the middle part 4C are detachably combined with each other in the longitudinal direction A, and the upper part 4B and the middle part 4C are detachably combined with each other in the longitudinal direction A. At the first parting surface P1, an upper end surface 71a of the sheathing 71 and a lower end surface 73a of the sheathing 73 are in contact with each other. At the second parting surface P2, a lower end surface 72a of the sheathing 72 and an upper end surface 73b of the sheathing 73 are in contact with each other. To achieve high assembly accuracy of the three sections 4A, 4B, and 4C, it is preferred that the two parting surfaces P1 and P2 are flat surfaces that are parallel to each other. In the figures shown, the two parting surfaces P1 and P2 are flat surfaces that are perpendicular to the longitudinal direction A. The lower part 4A comprises the casing 71 and the first reduction mechanism 10 and the first bearing 12, which are housed in the casing 71. The upper part 4B comprises the casing 72 and the second reduction mechanism 11 and the second bearing 13, which are housed in the casing 72. The central part 4C comprises the casing 73 and the two motors 8 and 9, which are housed in the casing 73. The first motor 8 rotates about an axis parallel to the longitudinal direction A to generate energy for rotating the first arm 4 about the second axis J2 with respect to the pivoting body 3. The second motor 9 rotates about an axis parallel to the longitudinal direction A to generate energy for rotating the second arm 5 about the third axis J3 with respect to the first arm 4. Input gears 8a and 9a, coupled to the reduction mechanisms 10 and 11, are each provided on the output shafts of the motors 8 and 9. It is preferred that the two motors 8 and 9 are arranged parallel to each other in a direction perpendicular to the longitudinal direction A. Fig. 2 shows the internal structure of the lower part 4A and the central part 4C as viewed from the opposite side of the swivel body 3 in a direction parallel to the second axis J2. The first reduction mechanism 10 is coupled to the first motor 8, reduces the rotational speed of the first motor 8, and transmits the rotation to the swivel body 3 at the reduced speed. Furthermore, the first reduction mechanism 10 converts the rotation of the first motor 8 into a rotation about the second axis J2. Specifically, the first reduction mechanism 10 comprises a first hypoid gear set 14 and an intermediate gear unit (a first coupling gear) 15 between the first motor 8 and the hypoid gear set 14. The hypoid gear set 14 has a ring gear (first output hypoid gear) 141 and a pinion unit (first input hypoid gear) 142 which are in mesh with each other. The ring gear 141 is arranged coaxially with the second axis J2 and is fixed to the swivel body 3 with screws. The pinion unit 142 is supported by bearings 20a and 20b in such a way that it can rotate on an axis parallel to the longitudinal direction A and engages with the ring gear 141 and the intermediate gear unit 15. For example, the pinion unit 142 has a bevel gear 142a that engages with the ring gear 141 and a spur gear 142b that engages with the intermediate gear unit 15. The intermediate gear unit 15 is arranged between the first motor 8 and the pinion unit 142 and is supported by bearing 12 and bearing 20c in such a way that an axis running parallel to the longitudinal direction A is rotatable. The intermediate gear unit 15 is coupled to the first motor 8 by being in mesh with the input gear 8a, with the lower part 4A being mechanically connected to the central part 4C. The rotation of the first motor 8 is transmitted to the swivel body 3 via the input gear 8a, the intermediate gear unit 15, the pinion unit 142, and the ring gear 141, and is converted by the gears 142 and 141 into a rotation about the second axis J2. Consequently, the first arm 4 is rotated relative to the swivel body 3. Fig. 3 shows the internal structure of the upper part 4b and the central part 4C as viewed from the opposite side of the wrist unit 6 in a direction parallel to the third axis J3. The second reduction mechanism 11 is coupled to the second motor 9, reduces the rotational speed of the second motor 9, and transmits the rotation at the reduced speed to the second arm 5. Furthermore, the second reduction mechanism 11 converts the rotation of the second motor 9 into a rotation about the third axis J3. Specifically, the second reduction mechanism 11 has a second hypoid gear set 16 and an intermediate gear unit (a second coupling gear) 17 between the second motor 9 and the hypoid gear set 16. The hypoid gear set 16 has a ring gear (second output hypoid gear) 161 and a pinion unit (second input hypoid gear) 162 which mesh with each other. The ring gear 161 is arranged coaxially with the third axis J3 and is fixed to the second arm 5 by screws. The pinion unit 162 is supported by bearings 20d and 20e in such a way that it can rotate on an axis parallel to the longitudinal direction A and engages with the ring gear 161 and the intermediate gear unit 17. For example, the pinion unit 162 has a bevel gear 162a that engages with the ring gear 161 and a spur gear 162b that engages with the intermediate gear unit 17. The intermediate gear unit 17 is arranged between the second motor 9 and the pinion unit 162 and is supported by bearing 13 and bearing 20f in such a way that it can rotate on an axis parallel to the longitudinal direction A. The intermediate gear unit 17 is coupled to the second motor 9 by being in mesh with the input gear 9a, with the upper part 4B being mechanically coupled to the central part 4C. The rotation of the second motor 9 is transmitted to the second arm 5 via the input gear 9a, the intermediate gear unit 17, the pinion unit 162, and the ring gear 161, and is converted by the gears 162 and 161 into a rotation about the third axis J3. Consequently, the second arm 5 is rotated relative to the first arm 4. As shown in Fig. 2, the bearing (first annular member) 12 is arranged such that it extends over the first parting surface P1 in the longitudinal direction A, and part of the bearing 12 and part of the intermediate gear unit 15 project in the longitudinal direction A from the upper end surface 71a at the first parting surface P1. The central part 4C has a circular recessed part 18 which is open towards the lower end surface 73a and in which part of the bearing 12 and part of the intermediate gear unit 15 are housed. An outer surface 12a of the part of the bearing 12 and an inner surface 18a of the recessed part 18 are cylindrical surfaces that are arranged coaxially with the intermediate gear unit 15 and form a first mating surface and a second mating surface respectively, which are fitted to each other in the longitudinal direction A. As shown in Fig. 3, the bearing (second annular member) 13 is arranged such that it extends over the second parting surface P2 in the longitudinal direction A, and part of the bearing 13 and part of the intermediate gear unit 17 project in the longitudinal direction A from the lower end surface 72a at the second parting surface P2. The central part 4C has a circular recessed part 19 which is open towards the upper end surface 73b and in which part of the bearing 13 and part of the intermediate gear unit 17 are housed. An outer surface 12a of the part of the bearing 13 and an inner surface 19a of the recessed part 19 are cylindrical surfaces that are arranged coaxially with the intermediate gear unit 17 and form a third mating surface and a fourth mating surface respectively, which are fitted to each other in the longitudinal direction A. Here, the central axis of bearing 12 and the central axis of bearing 13 are not positioned on the same straight line, but are arranged at positions that are offset from each other in a direction perpendicular to the longitudinal direction A. Consequently, the central axes of the first and second mating surfaces 12a and 18a, and the central axes of the third and fourth mating surfaces 13a and 19a, are also arranged at positions that are offset from each other in a direction perpendicular to the longitudinal direction A. Fig. 4A is a front view of the first arm 4 viewed in the horizontal direction from the side of the pivoting body 3 and the second arm 5. Fig. 4B is a side view of the first arm 4 viewed in the horizontal direction perpendicular to the second axis J2 and the third axis J3. As shown in Fig. 4A and Fig. 4B, the lower part 4A has a first reference surface 21 on its outer side, the upper part 4B has a second reference surface 22 on its outer side, and the middle part 4C has two third reference surfaces 23a and 23b on its outer side. Reference surfaces 21 and 23a serve to adjust the relative positions of the lower part 4a and the middle part 4C about the axis of the longitudinal direction A. Reference surfaces 22 and 23b serve to adjust the relative positions of the upper part 4B and the middle part 4C about the axis of the longitudinal direction A. The first reference surface 21 is a flat surface parallel to an output surface 10a of the first reduction mechanism 10 and is provided on an outer surface of the casing 71. The output surface 10a is a flat mounting surface attached to the pivoting body 3 and, in this embodiment, is an end surface of the ring gear 141 on the side of the pivoting body 3. The second reference surface 22 is a flat surface parallel to an output surface 11a of the second reduction mechanism 11 and is provided on an outer surface of the casing 72. The output surface 11a is a flat mounting surface attached to the second arm 5 and, in this embodiment, is an end surface of the ring gear 161 on the side of the second arm 5. The two output surfaces 10a and 11a are arranged on the same side of the first arm 4 and are parallel to each other. In this embodiment, the casing 7 has a flat side surface 7c on the side of the pivoting body 3 and the second arm 5, and the output surfaces 10a and 11a project from the side surface 7c. The two third reference surfaces 23a and 23b are provided on an outer surface of the casing 73 and are arranged in the longitudinal direction A. As described later, when a user assembles the first arm 4, the positional relationship between the reference surface 23a, which is located near the base end part 4a, and the first reference surface 21 is measured, as is the positional relationship between the reference surface 23b, which is located near the distal end part 4b, and the second reference surface 22. To facilitate the measurement, it is preferred that the third reference surface 23a is arranged in a line with the first reference surface 21 in the longitudinal direction A and that the third reference surface 23b is arranged in a line with the second reference surface 22 in the longitudinal direction A. In this embodiment, the four reference surfaces 21, 22, 23a, and 23b are arranged in a straight line in the longitudinal direction A on the flat side surface 7c. The two third reference surfaces 23a and 23b are flat surfaces parallel to the axes of the motors 8 and 9, and when viewed in the longitudinal direction A, form a predetermined angle with the first reference surface 21 and the second reference surface 22, which are parallel to each other. In this embodiment, the predetermined angle is 0° and the third reference surfaces 23a and 23b are parallel to the first reference surface 21 and the second reference surface 22. As shown in Fig. 2 and Fig. 4A, it is preferred that when viewing the reference surfaces 21 and 23a from the front, the reference surfaces 21 and 23a are arranged at positions that lie away from the central axis of the mating surfaces 12a and 18a in a direction perpendicular to the longitudinal direction A. As shown in Fig. 3 and Fig. 4A, it is preferred that when viewing the reference surfaces 22 and 23b from the front, the reference surfaces 22 and 23b are arranged at positions that lie away from the central axis of the mating surfaces 13a and 19a in a direction perpendicular to the longitudinal direction A. The assembly of the first arm 4 is described below. As shown in Fig. 5A and Fig. 5B, the first arm 4 is assembled using a positioning device 30 during manufacturing in a factory, etc. As shown in Fig. 5A, the positioning device 30 is composed of a horizontally arranged plate-shaped element and has an upper surface 31 and two flat positioning surfaces 32a and 32b for receiving the output surface 10a and output surface 11a of the reduction mechanisms 10 and 11, respectively. In this embodiment, the upper surface 31, which faces the flat side surface 7c, is a flat surface. The two positioning surfaces 32a and 32b are arranged in positions that are set back with respect to the upper surface 31. The two positioning surfaces 32a and 32b are parallel to each other and specifically exhibit a high degree of parallelism minus a defined parallelism tolerance required for the output surfaces 10a and 11a. As shown in Fig. 5B, in a state where the starting surfaces 10a and 11a are aligned with the positioning surface 32a and the positioning surface 32b respectively, the lower part 4A, the upper part 4B and the middle part 4C are combined together. Specifically, the bearing 12 is inserted into the recessed part 18 until the end faces 71a and 73a come into contact, allowing the mating surface 12a to fit into the mating surface 18a and engaging the input gear 8a of the first motor 8 and the intermediate gear unit 15, thereby combining the lower part 4A and the central part 4C. Similarly, the bearing 13 is inserted into the recessed part 19 until the end faces 72a and 73b come into contact, allowing the mating surface 13a to fit into the mating surface 19a and engaging the input gear 9a of the second motor 9 and the intermediate gear unit 17, thereby combining the upper part 4B and the central part 4C. After alignment and combination, the lower part 4A and the upper part 4B can also be fixed to the positioning device 30 by means of clamps 33. Then the lower part 4A, the upper part 4B and the middle part 4C are fixed together by any means, such as screws. To ensure high positional accuracy during the operation of the robot 1, the lower part 4A and the upper part 4B must be precisely aligned in the circumferential direction around the axis in the longitudinal direction A, so that the parallelism between the two starting surfaces 10a and 11a is within a specified tolerance. According to this embodiment, the alignment between the lower part 4A and the upper part 4B can be easily carried out using the positioning device 30, which has the positioning surfaces 32a and 32b, such that the parallelism between the two starting surfaces 10a and 11a is within the specified tolerance, ensuring the required assembly accuracy of the first arm 4. Furthermore, according to this embodiment, the lower part 4A and the central part 4C have mating surfaces 12a and 18a, respectively, which are provided coaxially with the intermediate gear unit 15 and are aligned in the longitudinal direction A. Thus, by aligning the mating surfaces 12a and 18a, the lower part 4A and the central part 4C can be aligned at the positions where the intermediate gear unit 15 and the input gear 8a are engaged. Consequently, a pin-like element is not required for aligning the lower part 4A and the central part 4C. Similarly, the upper part 4B and the central part 4C each have a mating surface 13a and a mating surface 19a, respectively, which are coaxial with the intermediate gear unit 17 and are aligned longitudinally A. Thus, by aligning the mating surfaces 13a and 19a, the upper part 4B and the central part 4C can be aligned at the positions where the intermediate gear unit 17 and the input gear 9a are engaged. Therefore, a pin-like element is not required for aligning the upper part 4B and the central part 4C. Furthermore, according to this embodiment, the bearings 12 and 13 are arranged at positions that are offset from each other in a direction intersecting the longitudinal direction A. Consequently, in a state where the lower part 4A and the upper part 4B are aligned with respect to the positioning surfaces 32a and 32b, the circumferential position of the central part 4C with respect to the lower part 4A and the upper part 4B is uniquely determined. Thus, no pin-like element is required to align the central part 4C in the circumferential direction with respect to the lower part 4A and the upper part 4B. Furthermore, according to this embodiment, the mating surfaces 12a and 13a are composed of the outer surfaces of the bearings 12 and 13 that support the intermediate gear units 15 and 17. Thus, it is not necessary to add additional annular links to the first arm 4 to provide the mating surfaces 12a and 13a. Furthermore, according to this embodiment, the two motors 8 and 9 are arranged in parallel. Thus, a short first arm 4 can be manufactured by a simple design modification in which the positions of the two motors 8 and 9 are simply changed in the longitudinal direction A. Furthermore, according to this embodiment, the first arm 4 is subdivided into sections 4A and 4B, which comprise the reduction mechanism 10 and the reduction mechanism 11 respectively, and section 4C, which comprises the motors 8 and 9. Thus, during assembly, such as when adjusting the backlash of the reduction mechanisms 10 and 11, the assembly can be carried out in the small units 4A and 4B. Consequently, the automation of the assembly process is facilitated. Furthermore, in the manufacture of the first arm 4, all sections 4A, 4B and 4C can be machined using a small machine tool (of small machine tools), thus enabling a reduction in machining costs. Furthermore, according to this embodiment, sections 4A, 4B, and 4C have reference surfaces 21, 22, 23a, and 23b. When sections 4A and 4B, which house the reduction mechanisms 10 and 11, are exchanged, reference surfaces 21, 22, 23a, and 23b are used, making it possible to assemble the first arm 4 with a high level of assembly accuracy, equivalent to that achieved before disassembly. For example, there is the case where, after the first arm 4 has been shipped, the lower part 4A is replaced by a user to exchange the first reduction mechanism 10. At this point, the lower part 4A is removed from the central part 4C, and then a new lower part 4A is connected to the central part 4C. Similarly, there is the case where, to replace the second reduction mechanism 11, the upper part 4B is removed from the central part 4C, and then a new upper part 4B is connected to the central part 4C. In this case, as shown in Fig. 4B, the user can use the reference surfaces 21, 22, 23a, and 23b to precisely align the lower part 4A and the upper part 4B. Fig. 4B shows the replacement of the upper part 4B. Before removing the upper part 4B from the central part 4C, the user uses a measuring instrument 40, such as a dial gauge, to measure the positional relationship between the reference surfaces 23b and 22 (for example, the parallelism between the reference surfaces 23b and 22). The user then combines a new upper part 4B with the central part 4C and remeasures the positional relationship between the reference surfaces 23b and 22 using the measuring instrument 40. The user then rotates the upper part 4B about the central axis of the mating surfaces 13a and 19a with respect to the central part 4C, positions the upper part 4B with respect to the central part 4C at the position where the positional relationship between the reference surfaces 23b and 22 corresponds to the positional relationship between them before removal, and fixes the upper part 4B to the central part 4C. Therefore, it is possible to do this without using a special device, such as...B. the positioning device 30, makes it possible to achieve a high degree of parallelism between the starting surfaces 10a and 11a, which corresponds to that before the exchange. At this point, the reference surfaces 22 and 23b are arranged at positions that lie away from the central axis of the fitting surfaces 13a and 19a in a direction perpendicular to the longitudinal direction A, whereby the upper part 4B and the central part 4C can be aligned with high positional accuracy. Similarly, when replacing the lower part 4A, the reference surfaces 21 and 23a are arranged at positions that lie away from the central axis of the mating surfaces 12a and 18a in a direction perpendicular to the longitudinal axis A, whereby the lower part 4A and the central part 4C can be aligned with a high positional accuracy. Although the embodiment and modification of the present disclosure have been described above, the arm limb and the robot of the present disclosure are not limited to the embodiment and modification described above and various changes can be made without deviating from the core of the present disclosure. For example, robot 1 is not limited to a vertical articulated robot and can also be any robot equipped with an arm segment and two segments rotatably connected to both end parts of the arm segment. The two motors 8 and 9 can also be arranged in series in the longitudinal direction A. The assembly of the first arm 4 can also be carried out without using the positioning device 30. For example, the lower part 4A and the upper part 4B can also be aligned to positions where the starting surfaces 10a and 11a become parallel to each other using any other means. In this case, when the lower part 4A and the upper part 4B are aligned, the central part 4C is automatically aligned, thus eliminating the need for an alignment element such as a pin. The third reference surfaces 23a and 23b can also be inclined to the first reference surface 21 and the second reference surface 22, respectively. Specifically, in a state where the first reference surface 21 and the second reference surface 22 are parallel to each other, the third reference surfaces 23a and 23b can also be arranged at a predetermined angle of more than 0° to the reference surfaces 21 and 22 when viewed in the longitudinal direction A. In this case, it is possible to position the lower part 4A relative to the central part 4C based on the positional relationship between the reference surfaces 21 and 23a, and to position the upper part 4B relative to the central part 4C based on the positional relationship between the reference surfaces 22 and 23b. It is also possible for only one of the third reference surfaces 23a and 23b to be provided on the central part 4C. The third reference surfaces 23a and 23b are not necessarily required. In this case, for example, when the upper part 4C is replaced, the positional relationship between the first reference surface 21 and the second reference surface 22 is measured, and the upper part 4B is positioned at the point where the first reference surface 21 and the second reference surface 22 become parallel to each other. The specific structures of the reduction mechanisms 10 and 11 can also be other structures, as long as rotations of the motors 8 and 9 can be transmitted to the two links 3 and 5. For example, gears for converting rotations of the motors 8 and 9 into rotations about the axes J2 and J3 can also be gears of other types, different from the hypoid gears 141 and 142 and 161 and 162. The links forming the mating surfaces and their arrangement can also be modified according to the specific structures of the reduction mechanisms 10 and 11. The first and second annular links are not limited to bearings 12 and 13 and can also be any annular or cylindrical links provided in the lower part 4A and the upper part 4B. The first and second annular links can also be provided in the central part 4C and arranged coaxially with the axes of the motors 8 and 9. In this case, cylindrical mating surfaces are provided on the lower part 4A and the upper part 4B for fitting onto cylindrical outer surfaces of the annular links. The following remarks are further disclosed with regard to the embodiments and modifications described above. (Note 1) Arm link comprising a longitudinal direction and a first end part and a second end part, both of which are end parts in the longitudinal direction, wherein the first end part is connected to a first link in such a way as to be rotatable about a first axis of rotation intersecting the longitudinal direction, and wherein the second end part is connected to a second link in such a way as to be rotatable about a second axis of rotation intersecting the longitudinal direction, wherein the arm link is composed of a first section comprising the first end part, a second section comprising the second end part, and a third section arranged between the first section and the second section, and wherein the first section, the second section, and the third section are connected to each other in the longitudinal direction, the third section comprising a first motor and a second motor, each of which rotates about axes parallel to the longitudinal direction.The first section comprises a first reduction mechanism that converts a rotation of the first motor into a rotation about the first axis of rotation and transmits this rotation to the first link, and the first reduction mechanism has a first coupling gear that is coupled to the first motor and is rotatable about an axis parallel to the longitudinal direction; the second section comprises a second reduction mechanism that converts a rotation of the second motor into a rotation about the second axis of rotation and transmits this rotation to the second link, and the second reduction mechanism has a second coupling gear that is coupled to the second motor and is rotatable about an axis parallel to the longitudinal direction; the first section and the third section have a first mating surface and a second mating surface, respectively, that are fitted to each other in the longitudinal direction.and the first mating surface and the second mating surface are cylindrical surfaces arranged coaxially with the first coupling gear or the first motor, the second section and the third section have a third mating surface and a fourth mating surface respectively, which are fitted to each other in the longitudinal direction, and the third mating surface and the fourth mating surface are cylindrical surfaces arranged coaxially with the second coupling gear or the second motor, and the first and second mating surfaces and the third and fourth mating surfaces are arranged in positions that are offset from each other in a direction perpendicular to the longitudinal direction. (Note 2) Arm link according to Note 1, wherein the first reduction mechanism comprises a first output hypoid gear which is arranged coaxially with the first axis of rotation and which is fixed to the first link, and a first input hypoid gear which is supported in such a way as to be rotatable about an axis parallel to the longitudinal direction and which engages with the first output hypoid gear, and the second reduction mechanism comprises a second output hypoid gear which is arranged coaxially with the second axis of rotation and which is fixed to the second link, and a second input hypoid gear which is supported in such a way as to be rotatable about an axis parallel to the longitudinal direction and which engages with the second output hypoid gear. (Note 3) Arm link according to note 1 or 2, wherein the first mating surface or the second mating surface is an outer surface of a first annular link provided in the first section or the third section, and the third mating surface or the fourth mating surface is an outer surface of a second annular link provided in the second section or the third section. (Note 4) Arm link according to note 3, wherein the first annular link is a first bearing provided in the first section and supporting the first coupling gear. (Note 5) Arm link according to note 3 or 4, wherein the second annular link is a second bearing provided in the second section and supporting the second coupling gear. (Note 6) Arm section according to one of Notes 1 to 5, wherein the first motor and the second motor are arranged parallel to each other in a direction perpendicular to the longitudinal direction. (Note 7) Arm section according to any one of Notes 1 to 6, wherein the first section, the second section and the third section are detachably combined, the first section has a first reference surface provided on an outside of the first section, the second section has a second reference surface provided on an outside of the second section, and the first reference surface is a flat surface parallel to an output surface of the first reduction mechanism, and the second reference surface is a flat surface parallel to an output surface of the second reduction mechanism. (Note 8) Arm segment according to Note 7, wherein the third section has third reference surfaces provided on an outside of the third section, and the third reference surfaces are flat surfaces arranged at a predetermined angle to the first reference surface and the second reference surface in a state in which the first reference surface and the second reference surface are arranged parallel to each other. (Note 9) Arm link according to note 7 or 8, wherein the first reference surface is located in a position which, when viewed from the front, is away from a central axis of the first mating surface and the second mating surface, and the second reference surface is located in a position which, when viewed from the front, is away from a central axis of the third mating surface and the fourth mating surface. (Note 10) Robot comprising the arm segment according to one of the notes 1 to 9, a first segment and a second segment. (Note 11) Robot according to Note 10, comprising: a pivoting body supported to be rotatable about a first axis with respect to a base; a first arm supported to be rotatable about a second axis perpendicular to the first axis with respect to the pivoting body; and a second arm supported to be rotatable about a third axis parallel to the second axis with respect to the first arm, wherein the pivoting body is the first member, the first arm is the arm member, and the second arm is the second member. Reference symbol list 1 Robot 3 Swivel body (first link) 4 First arm (arm link) 4A Lower part (first section) 4B Upper part (second section) 4C Middle part (third section) 4a Base end part (first end part) 4b Distal end part (second end part) 5 Second arm (second link) 8, 9 Motor 10, 11 Reduction mechanism 12, 13 Bearing (annular link) 12a, 13a, 18a, 19a Mating surface 141, 161 Ring gear (output hypoid gear) 142, 162 Pinion unit (input hypoid gear) 15, 17 Intermediate gear unit (coupling gear) 21, 22, 23a, 23b Reference surface A Longitudinal direction J2 Second axis (first axis of rotation) J3 Third axis (second axis of rotation) QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature JP 7101134

[0004]

Claims

Arm link comprising a longitudinal direction and a first end part and a second end part, both of which are longitudinal end parts, wherein the first end part is connected to a first link in such a way as to be rotatable about a first axis of rotation intersecting the longitudinal direction, and wherein the second end part is connected to a second link in such a way as to be rotatable about a second axis of rotation intersecting the longitudinal direction, wherein the arm link is composed of a first section comprising the first end part, a second section comprising the second end part, and a third section arranged between the first section and the second section, and wherein the first section, the second section, and the third section are connected to each other longitudinally, the third section comprising a first motor and a second motor, each rotating about axes parallel to the longitudinal direction.The first section comprises a first reduction mechanism that converts a rotation of the first motor into a rotation about the first axis of rotation and transmits this rotation to the first link, and the first reduction mechanism has a first coupling gear that is coupled to the first motor and is rotatable about an axis parallel to the longitudinal direction; the second section comprises a second reduction mechanism that converts a rotation of the second motor into a rotation about the second axis of rotation and transmits this rotation to the second link, and the second reduction mechanism has a second coupling gear that is coupled to the second motor and is rotatable about an axis parallel to the longitudinal direction; the first section and the third section have a first mating surface and a second mating surface, respectively, that are fitted to each other in the longitudinal direction.and the first mating surface and the second mating surface are cylindrical surfaces arranged coaxially with the first coupling gear or the first motor, the second section and the third section have a third mating surface and a fourth mating surface respectively, which are fitted to each other in the longitudinal direction, and the third mating surface and the fourth mating surface are cylindrical surfaces arranged coaxially with the second coupling gear or the second motor, and the first and second mating surfaces and the third and fourth mating surfaces are arranged in positions that are offset from each other in a direction perpendicular to the longitudinal direction. Arm link according to claim 1, wherein the first reduction mechanism comprises a first output hypoid gear which is arranged coaxially with the first axis of rotation and which is fixed to the first link, and a first input hypoid gear which is supported in such a way as to be rotatable about an axis extending parallel to the longitudinal direction and which engages with the first output hypoid gear, and the second reduction mechanism comprises a second output hypoid gear which is arranged coaxially with the second axis of rotation and which is fixed to the second link, and a second input hypoid gear which is supported in such a way as to be rotatable about an axis extending parallel to the longitudinal direction and which engages with the second output hypoid gear. Arm member according to claim 1 or 2, wherein the first mating surface or the second mating surface is an outer surface of a first annular member provided in the first section or the third section, and the third mating surface or the fourth mating surface is an outer surface of a second annular member provided in the second section or the third section. Arm link according to claim 3, wherein the first annular link is a first bearing provided in the first section and supporting the first coupling gear. Arm member according to claim 3 or 4, wherein the second annular member is a second bearing provided in the second section and supporting the second coupling gear. Arm section according to one of claims 1 to 5, wherein the first motor and the second motor are arranged parallel to each other in a direction perpendicular to the longitudinal direction. Arm element according to one of claims 1 to 6, wherein the first section, the second section and the third section are detachably combined, the first section has a first reference surface provided on an outside of the first section, the second section has a second reference surface provided on an outside of the second section, and the first reference surface is a flat surface parallel to an output surface of the first reduction mechanism, and the second reference surface is a flat surface parallel to an output surface of the second reduction mechanism. Arm member according to claim 7, wherein the third section has third reference surfaces provided on an outside of the third section, and the third reference surfaces are flat surfaces arranged at a predetermined angle to the first reference surface and the second reference surface in a state in which the first reference surface and the second reference surface are arranged parallel to each other. Arm member according to claim 7 or 8, wherein the first reference surface is arranged in a position which, when viewed from the front, is away from a central axis of the first mating surface and the second mating surface, and the second reference surface is arranged in a position which, when viewed from the front, is away from a central axis of the third mating surface and the fourth mating surface. Robot comprising the arm segment according to any one of claims 1 to 9, a first segment and a second segment. Robot according to claim 10, comprising: a pivoting body which is supported in such a way as to be rotatable about a first axis with respect to a base; a first arm which is supported in such a way as to be rotatable about a second axis perpendicular to the first axis with respect to the pivoting body; and a second arm which is supported in such a way as to be rotatable about a third axis parallel to the second axis with respect to the first arm, wherein the pivoting body is the first member, the first arm is the arm member and the second arm is the second member.

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