JP2016160964A - Translatory expansion mechanism and robot arm mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a translatory expansion mechanism and a robot arm mechanism that can relax restrictions on application environment.SOLUTION: A translatory expansion mechanism according to an embodiment comprises: a plurality of connection units 21 in a short square cylindrical shape connected to be bendable; and an emission part 30 which has a columnar body constituted with the connection units 21 restricted from being bent and becomes bendable from the state of the columnar body as the connection units 21 are released from being restricted from being bent, and that supports the columnar body. At least one of the connection units 21 comprises a bending joint.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a linear motion expansion / contraction mechanism and a robot arm mechanism.

  Robot devices are applied in various fields such as production lines, medical care and nursing care, and are expected to be applied in further fields in the future. The actual production line has a wide variety of workpiece types and work contents. In addition, the work contents vary in the field of care. In addition, there are various restrictions on the surrounding environment. For example, in the conventional articulated arm mechanism, the movement of the elbow joint is very large and the movement is not predictable, so that it is limited to use in an environment where a relatively large space can be secured. In addition, in the conventional linear motion joint arm mechanism, since the linear motion arm simply expands and contracts linearly, it may not be applicable to an environment where obstacles are scattered.

  An object of the present invention is to provide a linear motion expansion / contraction mechanism and a robot arm mechanism that can alleviate restrictions on the application environment.

  The linear motion expansion / contraction mechanism according to the present embodiment includes a plurality of short-tube-shaped connecting pieces connected to bendable and a columnar body formed by restraining the bending of the connecting pieces. And a support part for supporting the columnar body that is released from the state of the columnar body and is released from the state of the columnar body, and at least one of the connecting pieces includes a bending joint.

FIG. 1 is an external perspective view of a robot arm mechanism including a linear motion extension mechanism according to the present embodiment. FIG. 2 is a cross-sectional view showing the internal structure of the robot arm mechanism of FIG. FIG. 3 is a perspective view showing the structure of the arm portion of FIG. FIG. 4 is a diagram showing an internal structure of the bending joint mechanism of FIG. FIG. 5 is a side view of the arm portion of FIG. FIG. 6 is a perspective view showing another structure of the arm portion of FIG. FIG. 7 is a diagram showing the internal structure of the bending joint mechanism of FIG. FIG. 8 is a top view of the arm portion of FIG. FIG. 9 is a perspective view showing another structure of the arm portion of FIG. FIG. 10 is a perspective view showing another structure of the arm portion of FIG. FIG. 11 is a perspective view showing another structure of the arm portion of FIG.

  Hereinafter, the linear motion expansion / contraction mechanism according to the present embodiment will be described with reference to the drawings. In addition, the linear motion expansion-contraction mechanism which concerns on this embodiment can be used as an independent mechanism (joint). However, in the following description, the linear motion expansion / contraction mechanism according to this embodiment will be described by taking an articulated robot arm mechanism incorporating the linear motion expansion / contraction mechanism according to the first and second embodiments as an example. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.

  FIG. 1 is an external perspective view of a robot arm mechanism including a linear motion extension mechanism according to the present embodiment. FIG. 2 is a cross-sectional view showing the internal structure of the robot arm mechanism of FIG. The robot arm mechanism has a substantially cylindrical base 1, an arm 2 connected to the base 1, and a wrist 4 attached to the tip of the arm 2. The wrist part 4 is provided with an adapter (not shown). In 1st Embodiment, an adapter is provided in the rotation part of 6th rotating shaft RA6 mentioned later. A robot hand corresponding to the application is attached to the adapter provided on the wrist portion 4.

  The robot arm mechanism has a plurality of, here six, joint portions J1, J2, J3, J4, J5, and J6. The plurality of joint portions J1, J2, J3, J4, J5, and J6 are sequentially arranged from the base portion 1. In general, the first, second, and third joints J1, J2, and J3 are called the root three axes, and the fourth, fifth, and sixth joints J4, J5, and J6 change the posture of the robot hand 3. Called wrist 3 axis. The wrist 4 has fourth, fifth, and sixth joints J4, J5, and J6. At least one of the joint portions J1, J2, and J3 constituting the root three axes and a linear motion expansion / contraction joint. Here, the third joint portion J3 is configured as a linear motion expansion / contraction joint portion, particularly a joint portion having a relatively long expansion / contraction distance. The arm part 2 represents the expansion / contraction part of the linear motion expansion / contraction joint part J3 (third joint part J3).

  The first joint portion J1 is a torsion joint centered on the first rotation axis RA1 that is supported, for example, perpendicularly to the base surface. The second joint portion J2 is a bending joint centered on the second rotation axis RA2 arranged perpendicular to the first rotation axis RA1. A Z axis is defined parallel to the first rotation axis RA1. An orthogonal three-axis robot coordinate system (X, Y, Z) centering on the Z axis is defined. The third joint portion J3 is a joint in which the arm portion 2 expands and contracts linearly around a third axis (moving axis) RA3 arranged perpendicular to the second rotation axis RA2.

  The fourth joint portion J4 is a torsion joint centered on the fourth rotation axis RA4. The fourth rotation axis RA4 substantially coincides with the third movement axis RA3 when a later-described seventh joint portion J7 is not rotating, that is, when the entire arm portion 2 is linear. The fifth joint J5 is a bending joint centered on a fifth rotation axis RA5 orthogonal to the fourth rotation axis RA4. The sixth joint portion J6 is a bending joint centered on the sixth rotation axis RA6 that is perpendicular to the fourth rotation axis RA4 and perpendicular to the fifth rotation axis RA5.

  The arm support body (first support body) 11a that forms the base portion 1 has a cylindrical hollow structure formed around the first rotation axis RA1 of the first joint portion J1. The first joint portion J1 is attached to a fixed base (not shown). When the first joint portion J1 rotates, the arm portion 2 pivots left and right along with the shaft rotation of the first support 11a. The first support 11a may be fixed to the ground plane. In that case, the arm part 2 is provided in a structure that turns independently of the first support 11a. A second support part 11b is connected to the upper part of the first support 11a.

  The second support portion 11b has a hollow structure that is continuous with the first support portion 11a. One end of the second support portion 11b is attached to the rotating portion of the first joint portion J1. The other end of the second support portion 11b is opened, and the third support portion 11c is fitted so as to be rotatable on the second rotation axis RA2 of the second joint portion J2. The 3rd support part 11c has a hollow structure which consists of a scale-like exterior which is connected to the 1st support part 11a and the 2nd support part. The third support portion 11c is accommodated in the second support portion 11b and sent out as the second joint portion J2 is bent and rotated. The rear part of the arm part 2 that constitutes the linear motion expansion / contraction joint part J3 (third joint part J3) of the robot arm mechanism is housed in the hollow structure in which the first support part 11a and the second support part 11b are continuous by contraction. The

  The third support portion 11c is fitted to the lower end portion of the second support portion 11b so as to be rotatable about the second rotation axis RA2 with respect to the open end lower portion of the second support portion 11b. Thereby, a second joint portion J2 as a bending joint portion around the second rotation axis RA2 is configured. When the second joint portion J2 rotates, the arm portion 2 rotates in a vertical direction around the second rotation axis RA2, that is, performs a undulation operation.

  The fourth joint portion J4 is a torsional joint having an arm central axis along the expansion / contraction direction of the arm portion 2, that is, a fourth rotation axis RA4 that typically contacts the third movement axis RA3 of the third joint portion J3. When the fourth joint portion J4 rotates, the wrist portion 4 and the robot hand attached to the wrist portion 4 rotate about the fourth rotation axis RA4. The fifth joint J5 is a bending joint having a fifth rotation axis RA5 orthogonal to the fourth rotation axis RA4 of the fourth joint J4. When the fifth joint portion J5 rotates, the fifth joint portion J5 rotates up and down (vertical direction around the fifth rotation axis RA5) together with the robot hand from the fifth joint portion J5 to the tip. The sixth joint J6 is a bending joint having a sixth rotation axis RA6 perpendicular to the fourth rotation axis RA4 of the fourth joint J4 and perpendicular to the fifth rotation axis RA5 of the fifth joint J5. When the sixth joint portion J6 rotates, the robot hand turns left and right.

  As described above, the robot hand attached to the adapter of the wrist portion 4 includes the first, second, and third joint portions J1. J2. It is moved to an arbitrary position by J3, and is arranged in an arbitrary posture by the fourth, fifth, and sixth joint portions J4, J5, and J6. In particular, the length of the extension / contraction distance of the arm part 2 of the third joint part J3 enables the robot hand to reach a wide range of objects from the proximity position of the base 1 to the remote position. Further, the curvilinear expansion / contraction operation of the arm portion 2 of the third joint portion J3 makes it possible to relax the restriction of the application environment. The third joint portion J3 is characterized by a linear expansion / contraction operation realized by a linear motion expansion / contraction mechanism constituting the third joint portion J3 and a length of the expansion / contraction distance.

  FIG. 2 is a cross-sectional view showing the internal structure of the robot arm mechanism of FIG. The linear motion expansion / contraction mechanism has an arm part 2 and an injection part 30. The arm unit 2 includes a plurality of connecting pieces 21 connected in a row. The plurality of connecting pieces 21 are short cylindrical bodies having the same cross-sectionally R shape. The front and rear connecting pieces 21 are connected in a row so as to be bent by pins at the end portions of each other. The connecting piece 21 has a bending rotation axis parallel to the width direction of the connecting piece 21. The plurality of connecting pieces 21 connected in a row can be bent inward. However, since the cross section of the connecting pieces 21 has a square shape, the side plates of the adjacent connecting pieces 21 collide with each other to the outside. Does not bend. The plurality of connecting pieces 21 constitutes a columnar body having a certain rigidity by restraining inward bending. Further, the columnar body is separated into a plurality of connecting pieces 21 by releasing the bending restriction. Of the four plates constituting the connecting piece 21, each of the two plates provided perpendicular to the bottom plate is referred to as a side plate, and the plate provided opposite to the bottom plate is referred to as a top plate. A cylindrical portion is defined by the back surface of each plate. A linear gear (not shown) is formed on the surface of the bottom plate of the connecting piece 21 along the connecting direction. When the plurality of connecting pieces 21 are aligned in a straight line, the linear gears are connected in a straight line to form a long linear gear.

  The plurality of connecting pieces 21 are restrained from being bent by the injection portion 30 attached near the opening in the third support 11c. For example, the bending of the plurality of connecting pieces 21 is restricted by the constraining plate provided on the top plate surface of the connecting piece 21 straddling the top plate surfaces of the front and rear connecting pieces 21 by the injection unit 30. The injection unit 30 includes a plurality of upper rollers 31 and a plurality of lower rollers 32 supported by a rectangular tube-shaped frame 35. For example, the plurality of upper rollers 31 and the plurality of lower rollers 32 are arranged along the arm center axis at an interval substantially equal to the length of the connecting piece 21. The connecting pieces 21 guided to the injection unit 30 are linearly aligned by the upper roller 31 and the lower roller 32 and supported by the plurality of upper rollers 31 and the plurality of lower rollers 32. A part of the injection plate 30 behind the bottom plate is cut out, and a drive gear 50 is provided in the cut out part. The position where the drive gear 50 is provided corresponds to the position of the linear gear provided on the bottom plate surface of the connecting piece 21. The drive gear 50 is connected to the motor 55 via a speed reducer (not shown). The drive gear 50 is meshed with a linear linear gear. The linear gear connected in a straight line forms a rack and pinion mechanism together with the drive gear 50.

  When the arm is extended, the motor 55 is driven and the drive gear 50 rotates forward, whereby the plurality of connecting pieces 21 are fed forward from the injection unit 30. At this time, the plurality of connecting pieces 21 are constrained to be bent inward by the injection portion 30 to form a columnar body. When the arm contracts, the motor 55 is driven and the drive gear 50 rotates in the reverse direction, whereby the columnar body is pulled back to the injection unit 30. At this time, the columnar body is released from the bending restriction at the injection portion 30 and separated into the connecting pieces 21. The separated connecting piece 21 is bent in a direction along the first rotation axis RA1 and stored in the first support 11a.

  The linear motion extension / contraction mechanism according to the present embodiment has a seventh joint portion J7. One connecting piece 21 among the plurality of connecting pieces 21 constituting the arm portion 2 has a bending joint mechanism constituting the seventh joint portion J7. The seventh joint J7 is a bending joint centered on a seventh rotation axis RA7 parallel to the bending rotation axis of the connecting piece 21. Hereinafter, the connecting piece 21 including the bending joint mechanism having the seventh rotation axis RA7 parallel to the bending rotation axis of the connecting piece 21 is referred to as a joint piece 25. In the robot arm mechanism shown in FIG. 2, the seventh rotation axis RA7 is a rotation axis parallel to the second rotation axis RA2. When the seventh joint portion J7 rotates, from the joint piece 25 to the tip, the seventh joint portion J7 rotates in the vertical direction around the seventh rotation axis RA7, that is, performs a undulation operation.

Hereinafter, the structure of the joint piece 25 having the bending joint mechanism will be described with reference to FIGS. FIG. 3 is a perspective view showing the structure of the arm portion 2 of FIG. FIG. 4 is a diagram showing an internal structure of the arm portion 2 of FIG. FIG. 5 is a side view of the arm portion 2 of FIG.
The joint piece 25 includes a first piece member 251 and a second piece member 252. The first frame member 251 has a concave shape (C shape) in the longitudinal section. The second frame member 252 has a convex shape (inverted T shape) in the longitudinal section. The second piece member 252 is rotatably fitted to the first piece member 251. A rotating shaft is fixed to both edge portions on the rear side of the first piece member 251. The rotation shaft is fixed in parallel to the bending rotation axis of the connecting piece 21. The rotation shaft has a seventh rotation axis RA7 parallel to the bending rotation axis. A second top member 252 is rotatably provided on the rotating shaft via a bearing. For example, a stepping motor is incorporated in the second piece member 252 as an actuator. A rotation shaft is connected to the drive shaft of the stepping motor via a gear or the like. According to the bending joint mechanism of the joint piece 25 described above, the first piece member 251 can be rotated about the seventh rotation axis RA7 with respect to the second piece member 252 by the rotation of the stepping motor. That is, the portion from the joint piece 25 to the tip of the arm portion 2 can be raised and lowered around the seventh rotation axis RA7. Both edge portions of the bottom portion of the second piece member 252 are notched in a tapered shape so that the cross section is a mountain shape. Thereby, as shown in FIG. 5, the movable range of the angle θ <b> 1 that undulates up and down of the seventh joint portion J <b> 7 can be expanded to an angle exceeding 90 degrees in the vertical direction.

  According to the linear motion expansion / contraction mechanism according to the present embodiment described above, a bending joint that bends up and down can be incorporated into the arm portion 2 that linearly expands and contracts. Thereby, the robot hand attached to the adapter of the wrist part 4 can be made to reach the target position through a route other than a straight line. For example, even when there is an obstacle on a straight line connecting the opening of the third support 11c and the target position, the robot hand can reach the target position while avoiding the obstacle from above or below. Therefore, according to the linear motion expansion / contraction mechanism according to the present embodiment, restrictions on the application environment can be relaxed.

(Modification)
The seventh joint portion J7 may be a bending joint centered on a seventh rotation axis RA7 parallel to the Z axis perpendicular to the bending rotation axis of the connecting piece 21 parallel to the Y axis. One of the plurality of connecting pieces 21 has a bending joint mechanism constituting the seventh joint portion J7. In the modification, the seventh joint portion J7 has a seventh rotation axis RA7 orthogonal to the bending rotation axis of the connecting piece 21. Hereinafter, the connecting piece 21 including the bending joint mechanism having the seventh rotation axis RA7 orthogonal to the bending rotation axis of the connecting piece 21 is referred to as a joint piece 27. In this case, when the seventh joint portion J7 rotates, it turns to the left and right about the seventh rotation axis RA7 from the joint piece 27 to the tip. FIG. 6 is a perspective view showing another structure of the arm portion 2 of FIG. FIG. 7 is a view showing the internal structure of the arm portion 2 of FIG. FIG. 8 is a top view of the arm portion 2 of FIG. Here, it is assumed that the seventh rotation axis RA7 is orthogonal to the bending rotation axis of the connecting piece 21 and the third movement axis RA3. In other words, the seventh rotation axis RA7 is a rotation axis parallel to the thickness direction of the connecting piece 21.

  The joint piece 27 includes a third piece member 271 and a fourth piece member 272. The third frame member 271 has a concave shape (C shape) in cross section. The fourth frame member 272 has a convex shape (inverted T shape) in the longitudinal section. A fourth frame member 272 is rotatably fitted to the third frame member 271. A rotating shaft is fixed to both edge portions of the skirt portion of the third frame member 271. The rotation shaft is fixed so as to be orthogonal to the bending rotation axis of the connecting piece 21 and the third movement axis RA3. The rotation shaft has a seventh rotation axis RA7 orthogonal to the bending rotation axis and the third movement axis RA3. A fourth frame member 272 is rotatably provided on the rotating shaft via a bearing. For example, a stepping motor is incorporated in the fourth frame member 272 as an actuator. A rotation shaft is connected to the drive shaft of the stepping motor via a gear or the like. According to the bending joint mechanism of the joint piece 27 described above, the third piece member 271 can be rotated about the seventh rotation axis RA7 with respect to the fourth piece member 272 by rotating the stepping motor. That is, the portion from the joint piece 27 to the tip of the arm portion 2 can be turned left and right about the seventh rotation axis RA7. Both edge portions of the fourth frame member 272 are notched so that the longitudinal section thereof is a mountain shape. Thereby, as shown in FIG. 8, the movable range of the angle θ2 of turning to the right and left of the seventh joint portion J7 can be expanded to an angle exceeding 90 degrees on each of the left and right.

  According to the linear motion expansion / contraction mechanism according to the modified example of the present embodiment described above, a bending joint that bends left and right can be incorporated into the arm portion 2 that linearly expands and contracts. Thereby, the robot hand attached to the adapter of the wrist part 4 can be made to reach the target position through a route other than a straight line. For example, even when there is an obstacle on a straight line connecting the opening of the third support 11c and the target position, the robot hand can reach the target position while avoiding the obstacle from the left or the right. it can. Therefore, according to the linear motion expansion / contraction mechanism according to the modification of the present embodiment, it is possible to relax the restriction of the application environment.

  In addition, the arm part 2 which comprises the linear motion expansion-contraction mechanism which concerns on this embodiment may be provided with the some bending joint with the same direction of a rotating shaft. For example, as shown in FIG. 9, the arm unit 2 may include a plurality of, here two bending joints. Two joint pieces 25 out of the plurality of connection pieces 21 include a bending joint mechanism having seventh and eighth joint portions J7 and 8 parallel to the bending rotation axis of the connection piece 21. For example, as shown in FIG. 10, among the plurality of connecting pieces 21, two joint pieces 27 are seventh and eighth joint portions J7 orthogonal to the bending rotation axis of the connecting piece 21 and the third movement axis RA3. , 8 may be provided.

  Furthermore, the arm part 2 which comprises the linear motion expansion-contraction mechanism which concerns on this embodiment may be provided with the multiple types of bending joint from which the direction of a rotating shaft differs. For example, as shown in FIG. 11, among the plurality of connecting pieces 21, the joint piece 25 includes a bending joint mechanism that forms a seventh joint portion J7 parallel to the bending rotation axis of the connecting piece 21, and the joint piece 27 is connected. You may provide the bending joint mechanism which comprises the 8th joint part J8 orthogonal to the bending | flexion rotation axis of the top | top | piece 21, and an arm center axis | shaft.

  As described above, by incorporating a plurality of bending joints in the arm section 2 that linearly expands and contracts, the robot hand can reach the target position through a more complicated path than the arm section 2 including one bending joint. it can.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Base part, 2 ... Arm part, 4 ... Wrist part, J1, J2, J4, J5, J6, J7 ... Rotary joint part, J3 ... Linear motion joint part, 11a ... 1st support body, 11b ... 2nd support body , 11c ... third support, 21 ... connecting piece, 25, 27 ... joint piece, 30 ... injection part, 31 ... upper roller, 32 ... lower roller, 50 ... drive gear, 55 ... motor

Claims (7)

A plurality of short-tube-shaped connecting pieces connected to bendable, and a columnar body is formed by restraining the bending of the connecting piece. Return to a bendable state,
A support portion for supporting the columnar body,
At least one of the connecting pieces includes a bending joint.   2. The linear motion expansion / contraction mechanism according to claim 1, wherein a rotation axis of the bending joint is parallel to a bending rotation axis of the connecting piece.   The linear motion expansion / contraction mechanism according to claim 2, wherein two or more of the plurality of connecting pieces have the bending joint.   2. The linear motion expansion / contraction mechanism according to claim 1, wherein a rotation axis of the bending joint is orthogonal to a bending rotation axis of the connecting piece.   The linear motion expansion / contraction mechanism according to claim 4, wherein a rotation axis of the bending joint is orthogonal to a central axis of the columnar body.   6. The linear motion expansion / contraction mechanism according to claim 5, wherein two or more connecting pieces among the plurality of connecting pieces have the bending joint. 6. The linear motion expansion / contraction mechanism according to claim 5, wherein at least one of the plurality of connecting pieces has a bending joint having a rotation axis parallel to a bending rotation axis of the connecting piece.