TWI805890B - flex mesh gearing - Google Patents

Abstract

The present invention provides a manipulator capable of improving the service life of a main bearing of a deceleration device provided at a joint, and a flexural engagement type deceleration device suitable for the manipulator. The manipulator includes: a first arm member (13), a second arm member (17), and a driving device (19) for driving the second arm member (17) relative to the first arm member (13). The driving device (19) has: a fixed member (51) fixed to the first arm member (13), a speed reduction mechanism (50), and a rotation decelerated by the speed reduction mechanism (50) is transmitted and connected to the second arm member (17). ) of the output member (52), the main bearing (59) arranged between the fixed member (51) and the output member (52). When viewed from the radial direction of the main bearing (59), the center of gravity (G17) of the second arm member (17) overlaps with the range (W1) of the rolling surface of the rolling elements of the main bearing.

Description

flex mesh gearing

The invention relates to a manipulator and a flexural meshing gear device.

An industrial manipulator has an arm and a joint that turns the arm, and the joint is provided with a speed reducer that decelerates rotational motion generated by a motor or the like and transmits it to the arm (for example, refer to Patent Document 1). The speed reducer 31 provided at the joint of Patent Document 1 includes a housing 31b fixed to a frame, an input gear 31a for inputting rotational motion, and an output shaft 31c connected to the arm 4 . As shown in FIG. 2 and FIG. 4 of Patent Document 1, the arm 4 of an industrial manipulator is often connected to the axially outer side of the output shaft 31c of the reducer 31, and extends from the connecting portion along the radius of rotation. configuration. (Prior Art Literature) (patent documents) Patent Document 1: Japanese Patent Laid-Open No. 2014-69269

(Problem to be solved by the present invention) The speed reducer is provided with: a fixed member connected to the base member, an output member connected to the target member which is an output target of power, and a main bearing disposed between the fixed member and the output member. In addition, the output member is rotatably supported by the fixed member via the main bearing. As in the conventional industrial manipulator mentioned above, when the arm is connected to the axially outer side of the output member of the reducer and arranged to extend from there in the radial direction of rotation, the main bearing is used as the fulcrum, and the slave arm is extended in the longitudinal direction. The moment arm becomes longer when the load is applied. The moment arm represents the distance between the fulcrum and the line of action of the force. The product of the load and the moment arm is the moment applied to the fulcrum. Therefore, if the moment arm of the reducer is longer, a large moment will be applied to the main bearing even if the load is small. Therefore, a reduction gear with a long arm is installed in a conventional industrial robot in a joint, and a large moment tends to be applied to the main bearing of the reduction gear, resulting in a problem that the life of the main bearing is shortened. An object of the present invention is to provide a manipulator capable of improving the service life of a main bearing of a reduction gear provided at a joint, and a flexural engagement type reduction gear suitable for the manipulator. (means to solve problems) The manipulator related to the present invention has: a first arm member, a second arm member, and a driving device for driving the second arm member relative to the first arm member, The manipulator is composed as follows: The driving device has: a fixed member fixed to the first arm member, a speed reduction mechanism, an output member that transmits the rotation decelerated by the speed reduction mechanism and is connected to the second arm member, and is disposed between the fixed member and the output member. between main bearings, When viewed from the radial direction of the main bearing, the center of gravity of the second arm member overlaps with the range of the rolling surfaces of the rolling elements of the main bearing. The flexurally meshed gear device related to the present invention includes: an oscillating body, an external gear flexibly deformed by the oscillating body, a first internal gear and a second internal gear meshing with the external gear, arranged on the first the main bearing between the internal gear and the second internal gear, The flexurally meshed gear unit is constructed as follows: The first internal gear is rotatable integrally with the outer ring of the main bearing, the second internal gear is rotatable integrally with the inner ring of the main bearing, The second internal gear has an extension portion extending radially outward of an outer ring member constituting the main bearing. (Effect of Invention) According to the present invention, it is possible to improve the life of the main bearing of the reduction mechanism provided at the joint between the first arm member and the second arm member.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a side view showing a manipulator according to an embodiment of the present invention. Fig. 2 is a rear view of the manipulator of Fig. 1 viewed from the rotation direction of the second arm. The manipulator 1 of the embodiment of the present invention is an industrial manipulator or a collaborative manipulator that works in cooperation with humans, specifically a multi-joint manipulator. The manipulator 1 includes: a base member 11, a first revolving arm 13, a first drive device 15, a second arm 17, a second drive device 19, a third arm 21, a third drive device 23, a fourth revolving arm 25, a 4. Driving device 27, fifth arm 29, fifth driving device 31, sixth arm 33, sixth driving device 35, processing head 41, and head driving device 43. Among them, the first swing arm 13 corresponds to an example of the first arm member related to the present invention. The second arm 17 corresponds to an example of a second arm member related to the present invention. The second driving device 19 corresponds to an example of a driving device related to the present invention. The base member 11 is fixed in the working space and becomes the base of the manipulator 1 . The first revolving arm 13 is rotatably supported by the base member 11 via the first driving device 15 . The second arm 17 is rotatably supported by the first swing arm 13 via the second drive device 19 . The third arm 21 is rotatably supported by the second arm 17 via the third drive device 23 . The fourth turning arm 25 is rotatably supported by the third arm 21 via the fourth driving device 27 . The fifth arm 29 is rotatably supported by the fourth swing arm 25 via the fifth drive device 31 . The sixth arm 33 is rotatably supported by the fifth arm 29 via the sixth drive device 35 . Focusing on the second arm 17, one end in the longitudinal direction of the second arm 17 is rotatably supported by the first swing arm 13 via the second driving device 19, and the other end in the longitudinal direction of the second arm 17 is The driving device 23 supports the third arm 21 in a rotatable manner. The first to sixth drive devices 15 , 19 , 23 , 27 , 31 , and 35 function as first to sixth joints between the arms, respectively. The first driving device 15 has: a fixed member connected to the base member 11, an output member supported by the fixed member so as to be rotatable about the rotary axis A1, a motor that generates power, and a motor that decelerates the rotational motion of the motor and transmits it to the output. The reduction mechanism of the component. The first revolving arm 13 is connected to the output member of the first drive device 15 , and is driven by the first drive device 15 to rotate around the revolving axis A1 . The second driving device 19 includes a fixed member 51 ( FIG. 3 ) connected to the first swing arm 13 , and an output member 52 ( FIG. 3 ) supported by the fixed member 51 so as to be rotatable around the rotation axis A2 . Furthermore, the second drive device 19 includes a motor 61 that generates power, and a reduction mechanism 50 that reduces the rotational motion of the motor 61 and transmits it to the output member 52 . The second arm 17 is connected to the output member 52 of the second drive device 19 , and is driven by the second drive device 19 to rotate around the rotation axis A2 . The third driving device 23 has: a fixed member connected to the second arm 17, an output member supported by the fixed member so as to be rotatable around the rotation axis A3, a motor that generates power, and decelerates the rotational motion of the motor and transmits it to the The reduction mechanism of the output member. The third arm 21 is connected to the output member of the third drive device 23 , and is driven by the third drive device 23 to rotate around the rotation axis A3 . The fourth driving device 27 has: a fixed member connected to the third arm 21, an output member rotatably supported by the fixed member around the rotation axis A4, a motor that generates power, and decelerates the rotational motion of the motor and transmits it to the The reduction mechanism of the output member. The fourth revolving arm 25 is connected to the output member of the fourth drive device 27 , and is driven by the fourth drive device 27 to rotate around the revolving axis A4 . The fifth driving device 31 has: a fixed member connected to the fourth swing arm 25, an output member supported by the fixed member so as to be rotatable around the rotation axis A5, a motor generating power, and decelerating and transmitting the rotational motion of the motor. to the reduction mechanism of the output member. The fifth arm 29 is connected to the output member of the fifth drive device 31 , and is driven by the fifth drive device 31 to rotate around the rotation axis A5 . The sixth driving device 35 has: a fixed member connected to the fifth arm 29, an output member rotatably supported by the fixed member around the rotation axis A6, a motor that generates power, and decelerates the rotational motion of the motor and transmits it to the The reduction mechanism of the output member. The sixth arm 33 is connected to the output member of the sixth drive device 35 , and is driven by the sixth drive device 35 to rotate around the rotation axis A6 . In addition, the driving devices on the processing head 41 side such as the fifth driving device 31 and the sixth driving device 35 may be configured such that power is transmitted from a motor provided at a position away from the driving unit. In addition, the driving devices on the processing head 41 side, such as the fifth driving device 31 and the sixth driving device 35, may be constructed such that the speed reduction mechanism is omitted, and the motion is transmitted without amplifying the torque. In each of the first to sixth driving devices 15, 19, 23, 27, 31, and 35, a bearing (hereinafter referred to as "main bearing") is provided between the fixed member and the output member, and the output member is rotatable via the main bearing. Or the way of rotation is supported by fixed components. The processing head 41 is held at the tip of the sixth arm 33 and performs processing such as welding on the object to be processed. The head driving device 43 is held by the third arm 21 and supplies energy such as laser light or electric power to the processing head 41 . With such a configuration, the manipulator 1 rotates the first and fourth rotating arms 13 and 25, and rotates the second, third, fifth and sixth arms 17, 21, 29 and 33, thereby being able to rotate along the 3 The machining head 41 is moved axially and its angle is changed. Thereby, the robot arm 1 can move the processing head 41 with a high degree of freedom, and can perform processing on various positions of the object to be processed from various angles. <Second Driving Device> FIG. 3 is a cross-sectional view showing a second arm and a second driving device. In this specification, unless otherwise specified, an axial direction means a direction along the rotation axis O1 of the second drive device 19 , and a radial direction means a direction perpendicular to the rotation axis O1 unless otherwise specified. The second drive device 19 includes the reduction mechanism 50 , the fixing member 51 , the output member 52 , the main bearing 59 , and the motor 61 as described above. Among these, the configuration of the combined reduction mechanism 50, the fixed member 51, the output member 52, and the main bearing 59 corresponds to an example of the flexural meshing type gear device related to the present invention. The reduction mechanism 50 includes an input shaft 53 having a vibrating body 53a, an external gear 55 flexibly deformed by the vibrating body 53a, a first internal gear 51g and a second internal gear 52g meshing with the external gear 55 . Furthermore, the reduction mechanism 50 further includes input bearings 58A and 58B supporting the input shaft 53 , and a vibrating body bearing 56 disposed between the external gear 55 and the vibrating body 53 a. The fixed member 51 is configured by connecting a first member 51A provided with a first internal gear 51g, a second member 51B in which an input bearing 58A is fitted, and a third member 51C in which a main bearing 59 is fitted. A part of the third member 51C functions as the outer ring of the main bearing 59 , so the fixing member 51 can rotate integrally with the outer ring of the main bearing 59 . The fixing member 51 corresponds to an example of an outer ring member related to the present invention. In addition, the fixing member 51 may integrally form the first member 51A, the second member 51B, and the third member 51C with one member, or may be divided into a plurality of members elsewhere and connected via a connecting member. Furthermore, since the fixing member 51 is an integral member with the first internal gear 51g, the fixing member 51 itself can be called a first internal gear. The output member 52 is constituted by connecting the first member 52A provided with the second internal gear 52g and fitted with the main bearing 59 outside, and the second member 52B fitted with the input bearing 58B. A part of the first member 52A functions as the inner ring of the main bearing 59 , so the output member 52 can rotate integrally with the inner ring of the main bearing 59 . The second member 52B has an extension portion 52ex extending from the outer peripheral side of the input bearing 58B, through the anti-motor side of the fixing member 51 , to the radially outer side of the fixing member 51 . The extension portion 52ex extends to a position closer to the motor side than the main bearing 59 in the axial direction. The motor side indicates the side on which the motor 61 is arranged in the axial direction, and the anti-motor side indicates the opposite side. The second member 52B has a form in which the side on which the main bearing 59 is arranged is positioned axially inward, and does not protrude axially outward beyond the input bearing 58B. In other words, in the axial direction of the reduction mechanism 50 , the anti-motor side end of the output member 52 is located at the same position as the anti-motor side end of the input bearing 58B, or axially inside. In addition, the output member 52 may form the first member 52A and the second member 52B integrally with one member, or may be divided into a plurality of members elsewhere and connected to each other via a connection member. Furthermore, since the output member 52 is an integral member with the second internal gear 52g, the output member 52 itself can be called a second internal gear. The input shaft 53 has: a vibrating body 53a that is hollow and has an elliptical shape (not necessarily a geometrically complete ellipse) in a cross section perpendicular to the rotation axis O1; The external shape of the cross section perpendicular to the rotation axis O1 is circular shaft portions 53b, 53c. A motor shaft 61 a of the motor 61 is connected to one end portion of the input shaft 53 via a connection member 61 b, and a driving force is input from the motor 61 . The input shaft 53 is rotated around the rotation axis O1 by the power of the motor 61 . The external gear 55 is a flexible cylindrical metal, and teeth are provided on the periphery. The external gear 55 is held so as to be rotatable relative to the vibrating body 53 a via the vibrating body bearing 56 . Of the first internal gear 51g and the second internal gear 52g, one meshes with the tooth portion from the central half of the external gear 55 in the axial direction, and the other meshes with the tooth portion from the central half of the external gear 55 in the axial direction. . The first internal gear 51 g is configured such that tooth portions are formed at corresponding positions on the inner peripheral portion of the first member 51A of the fixed member 51 . The 2nd internal gear 52g is comprised by the tooth part formed in the corresponding position of the inner peripheral part of the 1st member 52A of the output member 52. The input bearings 58A, 58B are sealed bearings provided with a lubricant sealing member. Therefore, no oil seal is provided between the input shaft 53 and the fixing member 51 and the output member 52, and the axial dimension of the device is shortened. The input bearing 58A is disposed between the second member 51B of the fixed member 51 and one (motor side) shaft portion 53 b of the input shaft 53 . The input bearing 58B is disposed between the second member 52B of the output member 52 and the other (anti-motor side) shaft portion 53 c of the input shaft 53 . The input shaft 53 is rotatably supported by the fixed member 51 and the output member 52 via input bearings 58A and 58B. The main bearing 59 is, for example, a crossed roller bearing, and can receive both an axial load and a radial load. The rolling elements of the main bearing 59 include a plurality of first rollers and a plurality of second rollers arranged in a direction crossing the rotation axis with the first rollers. The main bearing 59 is arranged between the inner peripheral side of the third member 51C of the fixed member 51 and the outer peripheral side of the first member 52A of the output member 52 . The output member 52 is supported rotatably relative to the fixed member 51 by the main bearing 59 . As described above, in the present embodiment, a part of the fixed member 51 functions as the outer ring of the main bearing 59 , and a part of the output member 52 functions as the inner ring of the main bearing 59 . However, the main bearing 59 may have a dedicated outer ring and inner ring, and the outer ring and the fixing member 51 may be fitted so that the outer ring can rotate integrally with the fixing member 51 . Alternatively, the inner ring and the output member 52 may be fitted so that the inner ring can rotate integrally with the output member 52 . The second driving device 19 is configured as described above, and drives the vibrating body 53 a of the input shaft 53 to rotate by the motor 61 . When the vibrating body 53 a rotates, the motion is transmitted to the external gear 55 . At this time, the external gear 55 is limited to a shape along the outer peripheral surface of the vibrating body 53a, and is bent in an elliptical shape when viewed from the axial direction. Furthermore, in the external gear 55, a portion at the position of the major axis of the ellipse when viewed from the axial direction meshes with the first internal gear 51g and the second internal gear 52g. Therefore, the external gear 55 does not rotate at the same rotational speed as the vibrating body 53 a, but the vibrating body 53 a relatively rotates inside the external gear 55 . And, with this relative rotation, the external gear 55 flexes and deforms so that the major axis position and the minor axis position of the ellipse when viewed from the axial direction move in the peripheral direction. The cycle of this deformation is proportional to the rotation cycle of the vibrating body 53a. When the external gear 55 flexes and deforms, the position of its major axis moves, whereby the meshing position of the external gear 55 and the first internal gear 51g changes in the direction of rotation. Here, the number of teeth of the external gear 55 is set to 100, and the number of teeth of the first internal gear 51g is set to 102. Due to the difference in the number of teeth, the meshing teeth of the external gear 55 and the first internal gear 51g gradually shift each time the meshing position of the teeth rotates once, and the external gear 55 rotates (autorotates). With the above-mentioned number of teeth, the rotational motion of the input shaft 53 is decelerated at a reduction ratio of 100:2 and transmitted to the external gear 55 . On the other hand, the meshing position of the external gear 55 and the second internal gear 52g also changes in the direction of rotation due to the rotation of the vibrating body 53a. Here, the number of teeth of the external gear 55 and the second internal gear 52g are set to be the same number. At this time, the external gear 55 and the second internal gear 52g do not rotate relative to each other, and the rotational motion of the external gear 55 is transmitted to the second internal gear 52g at a reduction ratio of 1:1. By such an operation, the rotational motion of the input shaft 53 is decelerated at a reduction ratio of 100:2 and transmitted to the second internal gear 52g, and the rotational motion is output to the output member 52 . <Connection of the 1st swing arm, the 2nd drive device, and the 2nd arm> As shown in FIG. In the cross section of FIG. 3 , only one connection point is shown, but a plurality of points in the peripheral direction are connected in the same manner. The first swing arm 13 is disposed on the motor side of the speed reduction mechanism 50 and connected to the fixing member 51 from the motor side. The first swing arm 13 is provided with a through-hole h1 in the direction in which the motor shaft 61a extends. The housing 61d of the motor 61 is fixed to the first swing arm 13 on the opposite side of the reduction mechanism 50, and the motor shaft 61a is connected to the input shaft 53 through the through hole h1. The second arm 17 has, on one end side in the longitudinal direction, a hollow portion 173 in which the reduction mechanism 50 is disposed, a first frame member 171 disposed on the motor 61 side of the hollow portion 173 , and a first frame member 171 disposed on the anti-motor side of the hollow portion 173 . 2 frame members 172. The first frame member 171 and the second frame member 172 are connected to, for example, a side wall portion provided so as to surround the hollow portion 173 to be integrated. The first frame member 171 is provided with a through-hole h2 leading to the hollow portion 173 in the axial direction of the reduction mechanism 50 . The first frame member 171 is connected to the extension part 52ex of the output member 52 via a connecting member C2 such as a bolt while passing through the through hole h2 of the connecting part between the fixing member 51 and the first pivoting arm 13 . The first frame member 171 is disposed closer to the motor side than the extension portion 52ex, and is connected to the extension portion 52ex from the motor side. In addition, the second frame member 172 may be connected to the output member 52 from the anti-motor side. As shown in FIG. 3 , when viewed in the radial direction of the reduction mechanism 50 (the radial direction of the main bearing 59 ), the center of gravity G17 of the second arm 17 is located in a range W1 overlapping the rolling surface of the main bearing 59 . Here, the center of gravity G17 of the second arm 17 represents the center of gravity of the total weights of components fixed to the second arm 17 and not moving relative to the second arm 17 (non-displacement). That is, in the example of the manipulator 1 of FIG. 1 , the center of gravity G17 of the second arm is formed by the weight of the constituent parts including the second arm 17 and the third driving device 23, except for the third arm that moves relative to the second arm 17. The weight of each constituent element from the arm 21 to the processing head 41 is calculated. FIG. 4 is a cross-sectional view showing a joint portion of a comparative example. The joint part of the comparative example is as follows: the first rotary arm 13 is connected to the fixed member 51 from the motor side through the connecting member C11, and the first frame member 171 of the second arm 17 is connected to the output from the anti-motor side through the connecting member C12. Member 52. In the comparative example, when the center of gravity G17 of the second arm 17 is the force acting point of the force exerted on the output member 52 in the radial direction with the main bearing 59 as the fulcrum, the moment arm L1 becomes longer. Therefore, when a load is applied from the center of gravity G17 of the second arm 17 in the radial direction of the reduction mechanism 50 , a large moment, which is the product of the load and the moment arm L1 , is applied to the main bearing 59 . On the other hand, in the second joint part of the present embodiment shown in FIG. The moment arm is close to zero. Therefore, in the joint portion of the present embodiment, even when a large load is applied from the center of gravity G17 of the second arm 17 in the radial direction of the reduction mechanism 50 , only a small moment is applied to the main bearing 59 . Therefore, in the second joint portion of the present embodiment, the life of the main bearing 59 can be improved as compared with the joint portion of the comparative example. However, a general manipulator sometimes includes a multi-joint arm in which a plurality of arms are sequentially connected so as to rotate in the same direction as each other. Turning in the same direction means that the rotation axes of the plurality of joints between the arms are parallel to each other. Here, the center of gravity of the main bearing provided in each joint part and the arm connected to the output member of the joint part is largely separated in the axial direction as shown in FIG. 4 . Furthermore, from the base side to the tip side of the multi-joint arm, the shifting direction of the center of gravity of the arm of each joint part is set to the same direction. In such a configuration, shifts in the centers of gravity of the plurality of arms from the root side to the tip side act cumulatively on the joints on the root side, resulting in an extremely unbalanced configuration. Usually, in order to prevent such a balance difference, the designer of the multi-joint arm designs so that the deviation of the center of gravity of a plurality of arms does not accumulate from the root side to the tip side. Specifically, in a combination of several joints and the arms connected thereto, the designer sets the shift direction of the center of gravity of the arm in the opposite direction to the direction of shift of the center of gravity of the arms of the other joints. Offset of the center of gravity of the plurality of arms from the root side to the tip side is offset midway. In addition, it is designed so that the overall balance becomes good in consideration of the respective weights of the plurality of arms and the shift amounts of the centers of gravity of the arms at the respective joints. However, such a design for adjusting the balance is very complicated, and if the specifications of all the arms from the root side to the tip side are not determined, it is difficult to realize an optimal design. However, in the second joint portion of the present embodiment, the center of gravity G17 of the second arm 17 is located at a position overlapping the range of the rolling surface of the main bearing 59 when viewed in the radial direction. Therefore, even in the case where the joints and the arms are spliced sequentially to form a multi-joint arm, there will not be a situation in which the center of gravity of each arm shifts and accumulates to greatly break the balance. Therefore, by applying the same configuration as the second driving device 19 and the second arm 17 of the present embodiment to a plurality of joints and a plurality of arms, a multi-joint arm capable of easily designing and adjusting a balanced manipulator can be obtained. advantages. Alternatively, it is possible to obtain the advantage of being able to design a multi-joint arm of a well-balanced manipulator even if the specifications of all the arms are not determined. Furthermore, according to the second driving device 19 of the present embodiment, the output member 52 which rotates integrally with the inner ring of the main bearing 59 has an extension portion 52ex extending radially outward of the fixed member 51 which rotates integrally with the outer ring. Furthermore, the second arm 17 is connected to the extension portion 52ex. Accordingly, even when a simple form such as a frame shape elongated in one direction is adopted as the second arm 17, it is possible to easily realize a configuration in which the center of gravity G17 of the second arm 17 is arranged at a radial position of the main bearing 59. Effect. Here, as a comparative example, a configuration is considered in which a member that rotates integrally with the outer ring of the main bearing 59 is connected to the second arm 17, and a member that rotates integrally with the inner ring of the main bearing 59 is fixed to the base end side. The first swing arm 13. In the configuration of this comparative example, the inner ring of the main bearing 59 is stationary and the outer ring rotates. Rolling bearings such as the main bearing 59 are characterized by less sliding wear than sliding bearings, but sliding wear in rolling bearings is difficult to be completely zero. In addition, when the same rotational speed is output, comparing the configuration in which the inner ring is stationary and extracts rotational motion from the outer ring with the configuration in which the outer ring is stationary and extracts rotational motion from the inner ring, the former configuration in which the outer ring is extracted rolls The sliding speed of the body is higher. Therefore, the latter configuration of extracting the inner ring can suppress the occurrence of sliding wear in the main bearing 59 to a low level. Therefore, in this embodiment, the second arm 17 is connected to the output member 52 which rotates integrally with the inner ring of the main bearing 59, and compared with the above-mentioned comparative example, the occurrence of sliding wear of the main bearing 59 can be further suppressed, and the life can be improved. This configuration is especially effective when the joint of a robot arm is used in a severe environment. Furthermore, according to the second driving device 19 of the present embodiment, the input bearing 58B on the anti-motor side is a sealed bearing. Therefore, there is no need to arrange the lubricant seal member 60 (see FIG. 4 ) on the opposite side of the motor from the input bearing 58B. Therefore, the axial dimension of the reduction mechanism 50 can be shortened, and the second arm 17 can be made thinner accordingly. Furthermore, the second drive device 19 according to the present embodiment has a form in which the second member 52B of the output member 52 does not protrude further axially outward than the input bearing 58B on the anti-motor side. Therefore, the dimension in the axial direction of the reduction mechanism 50 including the output member 52 can be shortened, and the second arm 17 can be made thinner accordingly. The embodiments of the present invention have been described above. However, the present invention is not limited to the above-mentioned embodiments. For example, in the above-mentioned embodiment, the first revolving arm 13 is shown as the first arm member related to the present invention, but as long as the first arm member related to the present invention is a member to which the fixing member of the drive device is fixed, its shape and structure There is no limit. For example, when the driving device according to the present invention is disposed on the most proximal side of the multi-joint arm, the base member of the multi-joint arm corresponds to the first arm member according to the present invention. Furthermore, in the embodiment, a multi-joint manipulator has been described as an example, but the type of manipulator is not particularly limited, and any manipulator having a first arm member and a second arm member can be widely used. Moreover, in the above-mentioned embodiment, the main bearing related to this invention was shown as the structure of a pair of main bearing. However, the main bearing may also be composed of a set of two or more pairs of bearings arranged differently in the axial direction. In this case, the "range of the rolling surface of the rolling element of the main bearing" related to the present invention is defined as the range from the rolling surface located on the most side in the axial direction to the rolling surface located on the other most side in the axial direction . In addition, in the above-mentioned embodiment, as the speed reduction mechanism 50 provided in the second joint part of the manipulator 1, the speed reduction mechanism of the flexural mesh type gear apparatus was shown. However, as the reduction mechanism provided in the driving device of the manipulator related to the present invention, reduction mechanisms such as an eccentric swing type reduction gear or a simple planetary reduction gear that obtains a deceleration effect by swinging an external gear or an internal gear by an eccentric body may also be used. As for the eccentric oscillating type reduction gear, a so-called center crank type eccentric oscillating type reduction gear in which the eccentric shaft is arranged on the axis of the reduction mechanism can be used, or two or more eccentric bodies can be arranged offset from the axis of the reduction mechanism. The so-called distributed eccentric swing type reduction gear. In addition, details shown in the embodiments can be appropriately changed without departing from the spirit of the invention.

1: manipulator 13: 1st swing arm 17: 2nd arm 19: The second driving device 50:Deceleration mechanism 51: Fixed components 51g: 1st internal gear 52: Export components 52ex: extension 52g: 2nd internal gear 53: Input shaft 55: External gear 56: Vibrator bearing 58A, 58B: input bearing 59: Main bearing 61: motor 61a: Motor shaft 61b: Connecting components C1, C2: Connecting components 171: 1st frame member 172: 2nd frame member G17: Center of gravity of the second arm W1: the range of the rolling surface

[ Fig. 1 ] is a side view showing a manipulator according to an embodiment of the present invention. [Fig. 2] is a rear view of the manipulator in Fig. 1 viewed from the rotation direction of the second arm. [ Fig. 3 ] is a sectional view showing a second arm and a second driving device. [ Fig. 4 ] is a cross-sectional view showing a joint portion of a comparative example.

13: 1st swing arm

17: 2nd arm

19: The second driving device

50:Deceleration mechanism

51: Fixed components

51A: 1st member

51B: 2nd member

51C: 3rd component

51g: 1st internal gear

52: Export components

52A: 1st member

52B: 2nd member

52ex: extension

52g: 2nd internal gear

53: Input shaft

53a: Oscillator

53b, 53c: Shaft

55: External gear

56: Vibrator bearing

58A, 58B: input bearing

59: Main bearing

61: motor

61a: Motor shaft

61b: Connecting components

61d: shell

171: 1st frame member

172: 2nd frame member

173: hollow part

C1, C2: Connecting components

G17: Center of gravity of the second arm

h1, h2: through hole

O1: axis of rotation

W1: the range of the rolling surface

Claims (5)

A flexurally meshed gear device comprising: a vibrating body, an external gear flexibly deformed by the vibrating body, a first internal gear and a second internal gear meshing with the external gear, and a first internal gear and a second internal gear arranged between the first internal gear and the external gear. The main bearing between the second internal gears is characterized in that the first internal gear is rotatable integrally with the outer ring of the main bearing, and the second internal gear is rotatable integrally with the inner ring of the main bearing. The second internal gear has an extension portion that overlaps the main bearing when viewed in the radial direction, and the extension portion extends radially outward of an outer ring member constituting the main bearing. The flexural meshing gear device according to claim 1, wherein the second internal gear includes: a first member provided with internal teeth, and a second member having the extension portion; the extension portion, when viewed from a radial direction It overlaps with the internal teeth of the above-mentioned first member. The flexural meshing gear device according to claim 2, further comprising: an input shaft having the vibrating body, and an input bearing supporting the input shaft, wherein the input bearing is arranged between the input shaft and the second member . The flexural meshing gear device according to claim 3, wherein, The second member does not protrude further axially outward than the input bearing. The flexural meshing gear device according to claim 1, wherein the extending portion extends to a position closer to the first internal gear side than the main bearing in the axial direction.

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