WO2017188407A1

WO2017188407A1 - Joint mechanism

Info

Publication number: WO2017188407A1
Application number: PCT/JP2017/016845
Authority: WO
Inventors: 尹　祐根
Original assignee: ライフロボティクス株式会社
Priority date: 2016-04-27
Filing date: 2017-04-27
Publication date: 2017-11-02
Also published as: JP2019111587A; TW201741095A

Abstract

The purpose of the present invention is to improve the safety of a joint mechanism by preventing the risk of the arms and fingers of an operator being inserted therein, without impeding the rotational operation of the joint mechanism. A joint mechanism that has: a fixed part; a mobile part (5) that is movably supported on the fixed part; a cover (15) that covers at least one portion of the mobile part (5) and that is formed as a bellows structure so as to be extensible/retractable; and a reinforcing plate (19) and that is installed inside the cover (15) to allow the cover (15) to deform in the movement direction of the mobile part (5) and to prevent the cover (15) from deforming in directions other than the movement direction of the mobile part (5).

Description

Joint mechanism

The embodiment of the present invention relates to a joint mechanism.

In recent years, the environment where robots are in the same space as users is increasing. The possibility of working in the vicinity of an operator is being investigated for industrial robots as well as nursing robots. If this situation is realized, it may be possible for a handicapped person who is supported by a robot to work as well as a normal person. The polar-coordinate robot arm mechanism equipped with a linear motion expansion / contraction mechanism that has been put to practical use by the inventors has no elbow joint and no singularity, so it does not move suddenly at high speeds in unexpected directions. And the motion of the end effector can be predicted, and its safety is very high, and a collaborative work between the robot and the worker is realized without the need for a safety fence. In an environment where the robot and the worker are close to each other and collaborate, there is not only the risk of the arm colliding with the worker, but also the risk of the operator's hand and arm being caught in the internal structure of the rotary joint. is assumed.

The purpose is to improve the safety of the joint mechanism without obstructing its operation and avoiding the danger of the operator's hand or arm being caught.

The joint mechanism according to the present embodiment includes a fixed portion, a movable portion that is movably supported by the fixed portion, a cover that is extendable by a bellows structure that covers at least a part of the movable portion, and movement of the movable portion. And a reinforcing plate attached to the inside of the cover in order to allow deformation of the cover with respect to the direction and prevent deformation of the cover with respect to directions other than the moving direction of the movable part.

FIG. 1 is an external perspective view of a robot arm mechanism to which the joint mechanism according to the present embodiment is applied. FIG. 2 is a side view of the robot arm mechanism of FIG. FIG. 3 is a perspective view of the robot arm mechanism of FIG. 1 viewed from the rear. FIG. 4 is a side view showing the saddle cover of FIG. FIG. 5 is a perspective view of the bowl-shaped cover of FIG. 6 is a side view of the saddle cover of FIG. FIG. 7 is a side view showing how the saddle-shaped cover of FIG. 4 is attached. FIG. 8 is a view showing a reinforcing plate attached to the bowl-shaped cover. FIG. 9 is a view showing a reinforcing plate attached to the arm cover.

Hereinafter, the joint mechanism according to the present embodiment will be described with reference to the drawings. The joint mechanism according to the present embodiment is a linear motion expansion / contraction mechanism (linear motion joint) or a rotary joint mechanism that can be applied to various robot arm mechanisms. An example will be described in which the joint mechanism according to the present embodiment is applied to a polar coordinate type robot arm mechanism provided with a linear motion expansion / contraction mechanism. Of course, the joint mechanism according to the present embodiment may be provided in a mechanism other than the robot arm mechanism.

FIG. 1, FIG. 2, and FIG. 3 show the appearance of a polar coordinate type robot arm mechanism provided with this linear motion expansion / contraction mechanism. On the base 1 of the robot arm mechanism, a column portion 2 forming a cylindrical body is installed. The support | pillar part 2 accommodates the 1st joint part J1. The first joint portion J1 is a rotational joint that rotates about the rotation axis RA1. The rotation axis RA1 is, for example, parallel to the vertical direction. The arm part 5 is turned by the rotation of the first joint part J1. The column part 2 includes a lower part 2-1 and an upper part 2-2. The lower part 2-1 is connected to the fixed part of the first joint part J1. The upper part 2-2 is connected to the rotating part of the first joint part J1, and rotates about the rotation axis RA1. The first and second top rows of the third joint portion J3 to be described later are housed in the hollow inside the column portion 2 that forms a cylindrical body. On the upper part 2-2 of the column part 2, a undulating part 4 for accommodating the second joint part J2 is installed. The second joint portion J2 is a rotary joint that rotates about the rotation axis RA2. The second joint portion J2 is provided as a joint mechanism according to the present embodiment. The rotation axis RA2 is horizontal, for example. The second joint portion J2 is installed on the upper portion 2-2 of the column portion 2. The arm unit 5 rotates upward or downward around the rotation axis RA2.

The third joint portion J3 is provided by a linear motion extending and retracting mechanism. The linear motion expansion / contraction mechanism has a structure newly developed by the inventors, and the movable range is clearly longer than that of a conventional prismatic joint. Although the arm portion 5 of the third joint portion J3 is freely bendable, the bending is limited when the arm portion 5 is fed forward from the support mechanism 25 at the base of the arm portion 5 along the central axis (extension / retraction center axis RA3), and linear rigidity is achieved. Is secured. When the arm part 5 is pulled back, the bending is recovered. The arm unit 5 includes a first frame row 51 and a second frame row 52. The first frame row 51 is composed of a plurality of first frames 53 that are connected to be freely bent. Each first frame 53 is formed in a substantially flat plate shape. The plurality of first frames 53 are connected in a row so as to be freely bent by a plurality of hinge portions. Each hinge portion connects adjacent pairs of first frames 53 at their end portions. The second frame row 52 includes a plurality of second frames 54. Each second frame 54 is a tube having a circular or polygonal cross-sectional shape or a semi-tube shape thereof. That is, the semi-tubular shape is either a semicircular ridge shape or a half-square ridge shape. Typically, each second piece 54 has a half-angled bowl shape in which a bottom plate and a two-side plate are combined at a right angle. The plurality of second frames 54 are connected in a row at a plurality of hinge portions so as to be freely bent. Each hinge portion connects adjacent pairs of second frames 54 at the end portions of the bottom plate. The bending of the second frame row 52 is locked at a position where the end surfaces of the side plates of the second frame 54 come into contact with each other. At that position, the plurality of second frame rows 52 are linearly arranged. The first first frame 53 of the first frame sequence 51 and the second second frame 54 of the second frame sequence 52 are connected by a combined frame 55. For example, the combined frame 55 has a shape obtained by combining the first frame 53 and the second frame 54.

The first frame row and the second frame row are pressed and joined to each other by a roller when passing through a roller unit (not shown). By joining, the first and second frame rows exhibit linear rigidity and constitute the columnar arm portion 5. The cross section of the arm portion 5 is, for example, rectangular. A drive gear is provided behind the roller unit. The drive gear is connected to the stepping motor via a speed reducer. A linear gear is formed in the center of the back surface of the first frame along the connecting direction. When a plurality of first frames are aligned in a straight line, adjacent linear gears are connected in a straight line to form a long linear gear. The drive gear 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. When the drive gear rotates forward, the first and second frame rows become columnar bodies and are sent forward. When the drive gear rotates in the reverse direction, the columnar body is pulled back and separated into first and second frame rows between the roller unit and the drive gear. For example, the first frame row constituting the columnar body maintains a horizontal posture by the guide roller and the drive gear, and the second frame row constituting the columnar body is pulled downward by gravity, whereby the second frame row and the second frame row are One frame sequence is separated from each other. The separated first frame row and second frame row return to a bendable state. The first frame row and the second frame row that have been returned to the bendable state are both stored in a substantially parallel state in the column portion 2 while being bent in the same direction (inner side).

The wrist part 6 is attached to the tip of the arm part 5. The wrist 6 is equipped with fourth to sixth joints J4 to J6. The fourth to sixth joints J4 to J6 are each provided with three orthogonal rotation axes RA4 to RA6. The fourth joint portion J4 is a rotary joint that rotates about a fourth rotation axis RA4 that substantially matches the expansion / contraction center axis RA3, and the end effector swings by the rotation of the fourth joint portion J4. The fifth joint J5 is a rotary joint that rotates around a fifth rotation axis RA5 that is arranged perpendicular to the fourth rotation axis RA4. The end effector tilts back and forth by the rotation of the fifth joint J5. . The sixth joint portion J6 is a rotary joint that rotates around a sixth rotation axis RA6 that is arranged perpendicular to the fourth rotation axis RA4 and the fifth rotation axis RA5. By the rotation of the sixth joint portion J6, The end effector is pivoted.

The end effector is attached to an adapter provided at the rotating part of the sixth joint part J6 of the wrist part 6. The end effector is moved to an arbitrary position by the first, second, and third joint portions J1, J2, and J3, and is disposed in an arbitrary posture by the fourth, fifth, and sixth joint portions J4, J5, and J6. In particular, the length of the expansion / contraction distance of the arm portion 5 of the third joint portion J3 enables the end effector to reach a wide range of objects from the proximity position of the base 1 to the remote position. 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.

The arm portion 5 formed into a columnar body by joining the first and second frame rows has a rectangular or almost circular cross section. The joined first and second frame rows are covered with an arm cover 15 having a flexible resin bellows structure, for example. One end portion of the arm cover 15 is connected to a joint portion of the wrist portion 6 with the arm portion 5, and the other end portion is connected to a hard cover 22 described later. The arm cover 15 has elasticity by using a bellows structure. The arm cover 15 expands and contracts linearly according to the expansion and contraction of the arm unit 5 and covers the entire arm unit 5. Further, a reinforcing plate (reinforcing plate 19 shown in FIG. 9, which will be described in detail later) for reinforcing the arm cover 15 is attached to the arm portion 5.

As described above, the second joint portion J2 of the robot arm mechanism is provided as the joint mechanism according to the present embodiment. As shown in FIGS. 4A and 4B, the second joint portion J2 includes a pair of side frames 32 as a fixing portion (supporting portion). The side frame 32 is placed on an upper portion of a support frame (link) as a casing of the support section 2. A cylindrical body 31 serving as a rotating portion that also serves as a motor housing is pivotally supported at both ends of the pair of side frames 32. The pair of side frames 32 are covered with a bowl-shaped hard cover 21. The side frame 32 is mounted on the upper part of the frame of the column 2 corresponding to the link between the first and second joints J1 and J2. A motor is fixed inside the cylindrical body 31 together with a gear box. An output shaft (drive shaft) of the gear box is fixed to one side frame 32. The cylindrical body 31 rotates with the rotation of the output shaft. The lug body 33 is fixed to the cylindrical body 31 in such a manner as to protrude forward along the radial direction from the peripheral surface thereof. The cylindrical body 31 and the lug body 33 constitute a rotating part. The lug body 33 is provided with the injection portion 35 that supports the first and second frame rows described above. When the cylindrical body 31 rotates, the injection part 35 also rotates with it, whereby the arm part 5 supported by the injection part 35 undulates. The first frame row and the second frame row sent out through the injection unit 35 and pulled back are changed in direction while sliding on the upper peripheral surface of the cylindrical body 31. The lug body 33 is covered with the cylindrical hard cover 22 together with the injection portion 35.

A bowl-shaped (groove-shaped) bowl-shaped cover 14 is stretched between the hard covers 21 and 22. The hard covers 21 and 22 approach or separate as the arm portion 5 moves up and down due to the rotation of the cylindrical body 31. In order to follow the change in the gap as the hard covers 21 and 22 approach / separate, the saddle-shaped cover 14 has, for example, a saddle shape having a U-shaped (horse-shoe-shaped) cross section as shown in FIGS. It has a flexible resin bellows structure. The cross section of the bellows structure may be C-shaped or U-shaped. The same

U-shaped flanges

16 and 17 are attached to both end faces of the bellows structure. The saddle-shaped cover 14 has a bellows structure, so that it expands and contracts as the hard covers 21 and 22 approach / separate. In the hard covers 21 and 22, the closer to the rotation center axis of the rotating part, the larger the distance to approach / separate with the rotation of the rotating part. Therefore, when viewed from the direction of the rotation axis RA2, the bowl-shaped cover 14 expands and contracts (deforms) so as to form a fan shape or an arc shape centering on the rotation center axis of the rotation portion.

Further, as shown in FIGS. 6 and 7, for example, two reinforcing plates (intermediate plates) 18-1 and 18-2 are provided on the inner side of the saddle-shaped cover 14 (the side facing the rotating portion). It is mounted in a direction orthogonal to the rotation direction of the rotating part (movable part). The reinforcing plates 18-1 and 18-2 separate the saddle-shaped cover 14 from the internal structure such as the rotating part (movable part) of the rotary joint mechanism and reinforce the saddle-shaped cover 14, that is, the rotating part (movable part). Deformation (collapse) of saddle-shaped cover 14 with respect to the moving direction, here, with respect to the rotational direction, and with respect to directions other than the moving direction of the movable part, that is, typically the radial direction crossing the rotational direction. This is a reinforcing member for the saddle-shaped cover 14 that is attached to the inside of the saddle-shaped cover 14 in order to prevent this. The reinforcing plates 18-1 and 18-2 are attached to the inner side of the mountain fold portion of the bellows structure of the bowl-shaped cover 14. Further, the reinforcing plates 18-1 and 18-2 are mounted with a uniform interval, for example, with respect to the maximum extension range of the saddle-shaped cover 14. As a result, the reinforcing plates 18-1 and 18-2 attached to the bowl-shaped cover 14 are arranged substantially evenly by moving in accordance with the expansion and contraction of the bowl-shaped cover 14. Therefore, since the entire saddle-shaped cover 14 can be reinforced in average, there is no possibility that the bellows structure will be crushed.

8 (a), 8 (b), and 8 (c) are diagrams showing the configuration of the reinforcing plates 18-1 and 18-2. The reinforcing plates 18-1 and 18-2 are typically thin plate members made of resin, as shown in FIG. 8B. As shown in FIG. 8A, the outer edge shape of the reinforcing plates 18-1 and 18-2 is formed in a U-shape (or C-shape or U-shape) that matches the inner surface shape of the bowl-shaped cover 14. .

In the vicinity of the lower end of the bowl-shaped cover 14 attached between the hard covers 21 and 22, a fan-shaped or arc-shaped curved portion (arc) formed by the bowl-shaped cover 14 along the lower end of the bowl-shaped cover 14. The rails 40 arranged in parallel with the shape of the rail (along the direction in which the bowl-shaped cover 14 expands and contracts) are provided. In this embodiment, for example, two

rails

40a and 40b are provided. As shown in FIGS. 8A and 8C, the two end portions (lower ends) of the reinforcing plates 18-1 and 18-2 are engaged with the

rails

40a and 40b in the engaged state.

Engaging portions

18a and 18b are formed to be slidable. The reinforcing plates 18-1 and 18-2 are provided between the inside of the bowl-shaped cover 14 and the

rails

40a and 40b. Thereby, the reinforcing plate 18 supports the hook-shaped cover 14 from the inside, and ensures the rigidity of the hook-shaped cover 14. The reinforcing plates 18-1 and 18-2 have outer peripheral portions mounted inside the saddle-shaped cover 14 and slidably engaged with the

rails

40a and 40b. The shape cover 14 (bellows structure) moves as it expands and contracts (deforms). Accordingly, the reinforcing plates 18-1 and 18-2 support the saddle-shaped cover 14 from the inside in a uniform arrangement with respect to the expansion / contraction direction (length direction) of the saddle-shaped cover 14 at all times. The upper surfaces of the

rails

40a and 40b (contact surfaces with the reinforcing plates 18-1 and 18-2) so that the reinforcing plates 18-1 and 18-2 can smoothly slide on the

rails

40a and 40b. In addition, a lubricating film may be applied. Moreover, you may comprise the

rails

40a and 40b with a member with lubricity. Further, a lubricating film may be applied to the engaging

portions

18a and 18b of the reinforcing plates 18-1 and 18-2, or a member having lubricity may be attached.

In addition, when the 2nd joint part J2 rotates to the attitude | position which the arm part 5 stood to the highest position, it is preferable on safety that the hard covers 21 and 22 close completely, and a clearance gap does not exist among them. At this time, the bellows-shaped cover 14 is in the most contracted state. The attachment member 23 is provided at a position recessed downward by a predetermined distance from the upper edge of the hard cover 21 so that the most contracted bellows-shaped cover 14 can be suitably accommodated inside the hard covers 21 and 22. The attachment member 24 is provided at a position recessed forward by a predetermined distance from the rear edge of the cover 22.

Thus, by covering the gap between the hard covers 21 and 22 that open and close following the movement of raising and lowering the arm portion 5 with the bellows-shaped saddle-shaped cover 14, the operator's hand is attached to the saddle-shaped cover 14 by any chance. Even if placed, the saddle-shaped cover 14 is reinforced by the reinforcing plates 18-1 and 18-2, so that the bellows structure is not crushed. For this reason, the penetration | invasion to the inner side of the joint part J2 of an operator's hand can be suppressed, and the danger pinched by the internal structure of a joint can be avoided.

Next, the reinforcing plate 19 for reinforcing the arm cover 15 will be described. 9A, 9B, and 9C are diagrams showing the configuration of the reinforcing plate 19. FIG. The reinforcing plate 19 separates the cover 15 from the internal structure (top row) such as the arm portion 5 (movable portion) of the linear motion joint mechanism and reinforces the cover 15, that is, the moving direction of the arm portion 5, here the moving axis. A cover for allowing deformation of the cover 15 in the direction of RA3 and preventing deformation (collapse) of the cover 15 in a direction other than the moving direction, that is, a direction that intersects the moving direction, typically perpendicular to the moving direction. 15 is a reinforcing member of the cover 15 that is mounted inside 15 in a direction orthogonal to the moving direction.

As shown in FIGS. 9A, 9B, and 9C, the reinforcing plate 19 has a typical shape in which the center is cut out in a rectangular shape in accordance with the rectangular shape of the cross section of the arm portion 5. Is a thin plate-like annular member made of resin. The outer peripheral shape of the reinforcing plate 19 has an outer shape corresponding to the shape of the cross section of the arm cover 15. Here, since the cross-sectional shape of the arm cover 15 is formed in a cylindrical shape close to a rectangle, the outer peripheral shape of the reinforcing plate 19 is also formed in a rectangular shape so as to match it. The reinforcing plate 19 is attached to the inner side of the mountain fold portion of the bellows structure of the arm cover 15 in the same manner as the reinforcing plates 18-1 and 18-2 attached to the bowl-shaped cover 14. Therefore, a space corresponding to the width from the outer periphery of the reinforcing plate 19 to the opening is ensured between the arm cover 15 and the arm portion 5. The reinforcing plate 19 is mounted near the center of the maximum extension range with respect to the expansion / contraction direction (length direction) of the arm cover 15.

As shown in FIG. 9 (c), the arm portion 5 is inserted into the opening of the reinforcing plate 19. Since the reinforcing plate 19 is not fixed to the arm portion 5, the inner edge of the opening slides on the surface of the arm portion 5 as the arm cover 15 expands and contracts in accordance with the expansion and contraction operation of the arm portion 5. When the reinforcing plate 19 moves, the opening of the reinforcing plate 19 and the arm portion 5 are rubbed. Therefore, the reinforcing plate 19 has sliding portions (mouth edges) 19-1 and 19-2 slightly longer than the plate thickness above and below the edge of the opening so that the reinforcing plate 19 can move smoothly. Is provided. A lubricant film is applied to the inner surfaces of the sliding portions 19-1 and 19-2 that come into contact with the arm portion 5, and the entire reinforcing plate 19 or at least the sliding portions 19-1 and 19-2 are made of a self-lubricating resin. May be.

Since the reinforcing plate 19 is mounted in the vicinity of the center with respect to the expansion / contraction direction (length direction) of the arm cover 15, the length of the arm cover 15 is the same regardless of the length of the arm portion 5. Located near the center. Accordingly, the reinforcing plate 18 can be supported from the inside of the arm cover 15 to ensure the rigidity of the arm cover 15 regardless of the length of the arm portion 5.

In this way, by covering the arm part 5 with the arm cover 15 having a bellows structure whose length changes in accordance with the linear movement, even if the operator's hand is placed on the arm cover 15, the arm cover 15 Since it is reinforced by the reinforcing plate 19, the bellows structure is not crushed. For this reason, it can suppress that an operator's hand contacts the arm part 5 which moves directly, and can avoid a danger.

In the above description, two reinforcing plates 18-1 and 18-2 are attached to the saddle-shaped cover 14, and one reinforcing plate 19 is attached to the arm cover 15. At least one reinforcing plate may be attached. In other words, one or three or more reinforcing plates may be attached to the bowl-shaped cover 14. Further, two or more reinforcing plates may be attached to the arm cover 15. When a plurality of reinforcing plates are mounted, they are arranged so as to be substantially uniform in the length direction with respect to each of the bowl-shaped cover 14 or the arm cover 15 as described above. In addition, about the saddle-shaped cover 14 and the arm cover 15, when there exists a range which needs reinforcement especially, you may add a reinforcement board in the range, and may narrow the space | interval which arrange | positions a reinforcement board.

Although several embodiments of the present invention have been described, these embodiments are presented as examples 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, 2 ... Support | pillar part, 4 ... Unraveling part, 5 ... Arm part, 6 ... Wrist part, 14 ... Cover, 15 ... Arm cover, 18 (18-1, 18-2), 19 ... Reinforcement plate, 21, 22 ... Hard cover, 32 ... Side frame, 31 ... Cylindrical body.

Claims

A fixed part;
A movable part supported movably on the fixed part;
A cover formed to be stretchable by a bellows structure covering at least a part of the movable part;
At least one reinforcing plate attached to the inside of the cover to allow deformation of the cover with respect to the moving direction of the movable part and to prevent deformation of the cover with respect to a direction other than the moving direction of the movable part. A joint mechanism characterized by:
The joint mechanism according to claim 1, wherein a rail is provided in the fixing portion along a direction in which the cover extends and contracts, and the reinforcing plate slides on the rail by the expansion and contraction of the cover.
The joint mechanism according to claim 1 or 1, wherein the plurality of reinforcing plates are arranged uniformly within a maximum extension range of the cover.
The joint mechanism is a linear motion joint;
The cover has a cylindrical shape,
The joint mechanism according to claim 1, wherein the reinforcing plate is an annular body having an outer peripheral shape that matches an inner shape of the cover.
The joint mechanism is a rotary joint;
The cover is configured in a bowl shape having a U-shaped or C-shaped cross section,
The joint mechanism according to claim 1, wherein the reinforcing plate is a U-shaped plate or a C-shaped plate aligned with the inside of the cover.
6. The joint mechanism according to claim 5, wherein the cover expands and contracts so as to form a fan shape or an arc shape centering on a rotation center axis of the rotating portion.