JP2018071704A - Linear motion expansion and contraction mechanism, and robot arm mechanism with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a weight of an arm part while suppressing strength degradation in a linear motion expansion and contraction mechanism.SOLUTION: A linear motion expansion and contraction mechanism comprises: a plurality of first segments 53 connected to one another at front and rear ends in a bendable manner; a plurality of second segments 54 connected to one another in a bendable manner at front and rear ends of bottom plates; a connection part 55 connecting a headmost first segment and a headmost second segment; and a support part 25 that supports the first and second segments movably in a front-back direction, joins the first and second segments to one another when the first and second segments move forward and separates the first and second segments from one another when the first and second segments move backward. The first and second segments become rigid when the first segments are joined to the second segments, and the first and second segments return to a bending state when they are separated from one another. One or both of the first and second segments gradually decrease in width toward the front.SELECTED DRAWING: Figure 5

Description

  Embodiments described herein relate generally to a linear motion extension mechanism and a robot arm mechanism including the same.

  Conventionally, articulated robot arm mechanisms have been used in various fields such as industrial robots. The inventors have achieved practical application of a linear motion expansion / contraction mechanism (Patent Document 1). This linear motion expansion / contraction mechanism is a very useful structure that expands the movable region of the polar coordinate type robot arm mechanism that does not require an elbow joint and increases its practicality.

  The linear motion expansion / contraction mechanism has a plurality of plate-shaped pieces that are flexibly connected and a plurality of U-shaped grooves that are also flexibly connected on the bottom plate side, and these are joined to each other. By doing so, a columnar arm portion that is straightened and has a certain rigidity is formed. When the motor of the linear motion expansion / contraction mechanism rotates forward, the arm portion that is rigid and becomes a columnar body is sent out from the arm support portion, and when it rotates in the reverse direction, the arm portion is pulled back. Behind the arm support portion, the joined state of the top is released and the rigid state is restored to the bent state. The two types of pieces recovered to the bent state are bent toward the bottom side of one of the pieces, and are accommodated inside the support column.

  As described above, the linear motion expansion / contraction mechanism requires a large number of frames, and thus the weight of the arm portion tends to increase. If the frame is made thinner, smaller, and lighter to reduce the weight of the arm portion, the strength of the frame itself and the strength of the hinge structure that connects the frames may be reduced, and the strength of the arm portion is reduced. On the other hand, if the strength of the arm portion is to be improved, the weight of the frame increases and the weight of the arm portion cannot be avoided. Thus, there was a trade-off between the weight reduction and strength improvement of the arm portion.

Japanese Patent No. 5435679

  The purpose is to reduce the weight of the arm portion while suppressing a decrease in strength in the linear motion expansion / contraction mechanism.

  The linear motion expansion / contraction mechanism according to an embodiment of the present invention includes a plurality of first pieces that are connected to bendable at the front and rear ends, a plurality of second pieces that are connected to bendable at the front and rear ends of the bottom plate, A coupling portion that couples the tops of the plurality of first frames and the tops of the plurality of second frames, and supports the first and second frames movably back and forth, and the first and second frames move forward. A support unit that joins the first and second frames when moving and separates the first and second frames when the first and second frames move backward; The frame is stiffened when the first frame is joined to the second frame, and the first and second frames return to a bent state when separated from each other, and one or both of the first and second frames Is characterized in that the width gradually decreases toward the front.

FIG. 1 is an external perspective view of a robot arm mechanism provided with a linear motion expansion / contraction mechanism according to the first embodiment. FIG. 2 is a side view of the robot arm mechanism of FIG. FIG. 3 is a diagram showing an internal structure of the robot arm mechanism of FIG. FIG. 4 is a diagram showing the robot arm mechanism of FIG. FIG. 5 is a diagram illustrating the arm portion of FIG. 3. FIG. 6 is a diagram illustrating the first frame of FIG. FIG. 7 is a diagram illustrating the second frame in FIG. 3. FIG. 8 is a diagram illustrating an arm unit according to a modification of the first embodiment. FIG. 9 is a diagram illustrating the second frame of FIG. FIG. 10 is a diagram illustrating an arm unit according to a modification of the first embodiment. FIG. 11 is a diagram showing the first frame of FIG. FIG. 12 is a diagram illustrating an arm portion of the linear motion expansion / contraction mechanism according to the second embodiment. FIG. 13 is a diagram illustrating an arm unit according to a modification of the second embodiment. FIG. 14 is a diagram illustrating an arm portion of a linear motion expansion / contraction mechanism according to the third embodiment. FIG. 15 is a diagram illustrating the second frame of FIG. FIG. 16 is a diagram showing an arm portion of a linear motion extension mechanism according to a modification of the third embodiment. FIG. 17 is a diagram illustrating the first frame of FIG. FIG. 18 is a diagram illustrating an arm portion of the linear motion extension mechanism according to the fourth embodiment. FIG. 19 is a diagram illustrating an arm portion of a linear motion expansion / contraction mechanism according to the fifth embodiment.

Hereinafter, a linear motion extension mechanism and a robot arm mechanism including the linear motion extension mechanism according to first to fifth embodiments will be described with reference to the drawings.
(First embodiment)
1 and 2 are external views of a polar coordinate type robot arm mechanism provided with a linear motion expansion / contraction mechanism according to the first embodiment. FIG. 3 shows the internal structure of the linear motion extension / contraction mechanism. FIG. 4 shows the robot arm mechanism with a graphic symbol. 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 arranged in order from the base 1. In general, the first, second, and third joint portions J1, J2, and J3 are referred to as the root three axes, and the fourth, fifth, and sixth joint portions J4, J5, and J6 are mainly end effectors (hand effect). This is called the wrist 3 axis that changes the posture of the genitalia. At least one of the joint portions J1, J2, and J3 constituting the base three axes is a linear motion expansion / contraction mechanism. Here, the third joint portion J3 is configured as a linear motion expansion / contraction mechanism.

  A base 1 of the robot arm mechanism is provided with a support column 2 that roughly forms a cylindrical body. The column part 2 is separated into upper and lower parts, and the lower frame 21 at the lower part of the column and the upper frame 22 at the upper part of the column are connected by the first joint part J1. The first joint portion J1 is a torsional joint centered on a first rotation axis RA1 perpendicular to the ground contact surface of the base 1. The lower frame 21 is connected to the fixed portion of the first joint portion J1. The upper frame 22 is connected to the rotating part of the first joint part J1. The arm portion 5 pivots horizontally by the rotation of the first joint portion J1.

  First and second frame rows 51 and 52 of a third joint portion J3 to be described later are housed in the hollow interiors of the frames 21 and 22 of the column portion 2 that forms a cylindrical body. On the support column 2, an undulating portion 4 that houses the second joint portion J2 is installed. The second joint portion J2 is a bending joint centered on the second rotation axis RA2 arranged perpendicular to the first rotation axis RA1. The undulating portion 4 has a pair of side frames 23 as a fixing portion of the second joint portion J2. The pair of side frames 23 are placed on the upper frame 22. The pair of side frames 23 supports a cylindrical body 24 as a rotating portion of the second joint portion J2 that also serves as a motor housing. A support portion (feeding mechanism) 25 is attached to the peripheral surface of the cylindrical body 24. The delivery mechanism 25 supports a roller unit 58, a drive gear 56, and a guide roller 57. The delivery mechanism 25 supports the first and second frame rows 51 and 52 so as to be movable back and forth, and also moves the first and second frames 53 and 54 when the first and second frame rows 51 and 52 move forward. When the first and second frame rows 51 and 52 are pulled back, the first and second frames 53 and 54 are separated. The arm portion 5 undulates up and down by the rotation of the second joint portion J2.

  The linear motion expansion / contraction mechanism that forms the third joint portion J3 has a structure newly developed by the inventors, has a limited linear motion range, and has a pull-in range that is the same length as the linear motion range. It is clearly distinguished from a solid linear joint. The third joint portion J3 is a linear motion expansion / contraction mechanism in which the arm portion 5 expands and contracts linearly about a third axis (moving axis) RA3 arranged perpendicular to the second rotation axis RA2. The third joint portion J3 causes the arm portion (columnar body) 5 to expand and contract back and forth while maintaining linear rigidity along the third movement axis RA3.

  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. As shown in FIG. 5, the first frame 53 is typically formed in a substantially flat plate shape. The first frame 53 is not limited to a flat plate shape, and may be a grooved body or a cylindrical body, and the cross-sectional shape thereof is also limited to a square (rectangular) shape such as a U-shape or a square shape. However, it may be a polygonal shape such as a triangle or a pentagon, a circular shape, an elliptical shape, or an arc shape in which a part of a circle or an elliptical shape is cut out. Here, the first frame 53 will be described as having a substantially flat plate shape.

  The second frame row 52 is composed of a plurality of second frames 54 that are flexibly connected. As shown in FIG. 6, the second frame 54 typically forms a groove-like body having a U-shaped cross section. The second frame 54 is not limited to a groove-like body having a U-shaped cross section, and various other cross-sectional groove-like or cylindrical bodies can be adopted. For example, the second frame 54 may be a cylindrical body having a rectangular cross section. The second frame 54 is a groove or cylinder, and its cross-sectional shape is not limited to a quadrangle (rectangle), but a polygon such as a triangle or pentagon, and a circle, ellipse, circle or ellipse. An arc shape in which a part of the arc is cut off may be used. Here, the second frame 54 is described as being configured as a groove-shaped body having a U-shaped cross section.

  As will be described later, the first frame 53 and the second frame 54 are joined. Under the above-described shapes of the first frame 53 and the second frame 54, the overall shape of the cross section in a state where the first frame 53 and the second frame 54 are joined is a quadrangle, a triangle, a rhombus, or a trapezoid. , Other polygons, H-shape, circle, oval.

  The second frame 54 is connected to bendable between the bottom plates. The bending of the second frame row 52 is limited 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 second frame row 52 is linearly arranged. The first first frame 53 in the first frame sequence 51 and the first second frame 54 in the second frame sequence 52 are connected by a combined frame 55.

  The connecting piece 55 is a block having a shape in which the upper part protrudes rearward from the lower part. The protrusion length with respect to the lower part of the upper part is half the length of the second frame 53. The upper part has the same thickness as the first frame 53 and the lower part has the same thickness as the second frame 54. The top first frame 53 is connected to the upper part so that it can be bent, and the top second frame 54 is connected to the lower part so that it can be bent. The connection position between the first frames 53 is shifted by ½ length with respect to the connection position between the second frames 54. The open / close position (connection position) of the front and rear second frames 54 is located at the front and rear center of the first frame 53. This position is equipped with a lock mechanism which will be described later.

  The first and second frame rows 51 and 52 are pressed and joined to the upper and lower rollers 59 of the support portion (roller unit 58) 58 having a rectangular tube shape. The joined first and second frame rows 51 and 52 constitute a columnar arm portion 5. If the first and second frames 53 and 54 have the above-described typical cross-sectional shapes, the first and second frames 53 and 54 are rigidly joined to form a linear columnar body. However, if the planar shape of the first and second pieces 53 and 54 is a trapezoidal shape or a partial shape of an annular shape, the first and second pieces 53 and 54 are hardened by joining to form curved columnar bodies. Eggplant.

  A drive gear (pinion) 56 is provided behind the row of rollers 59. The drive gear 56 is connected to a motor (not shown) via a speed reducer. As shown in FIG. 5B, a linear gear 239 is provided at the front and rear in the center of the inner wall of the first frame 53. When the plurality of first frames 53 are linearly aligned, the front and rear linear gears 239 are linearly connected to form a long linear gear (rack). The drive gear (pinion) 56 is meshed with a linear linear gear 239. The linear gear 239 connected in a straight line forms a rack and pinion mechanism together with the drive gear 56. When the drive gear 56 rotates forward, the arm portion 5 extends forward. When the drive gear 56 rotates in the reverse direction, the arm portion 5 is pulled back into the undulating portion 4 and contracts. The first and second frame rows 51 and 52 that are pulled back to the rear of the support portion 58 and released from the pressing by the upper and lower rollers 59 are separated from each other. The separated first and second frame rows 51 and 52 are returned to a bendable state. The first and second frame rows 51, 52 that have returned to the bendable state are bent in the same direction (the bottom plate side of the second frame 54) in the undulating portion 4, and are housed inside the column portion 2. At this time, the first frame row 51 is stored in a state substantially parallel to the second frame row 52.

  A wrist portion 6 is attached to the tip of the arm portion 5. The wrist 6 is equipped with fourth to sixth joints J4 to J6. The fourth to sixth joint portions J4 to J6 include three orthogonal rotation axes RA4 to RA6. The fourth joint portion J4 is a torsional rotary joint centered on a fourth rotation axis RA4 that substantially coincides with the expansion / contraction center axis RA3, and the end effector is swung and rotated by the rotation of the fourth joint portion J4. The fifth joint portion J5 is a bending rotation joint about the fifth rotation axis RA5 arranged perpendicular to the fourth rotation axis RA4, and the end effector is tilted back and forth by the rotation of the fifth joint portion J5. Is done. The sixth joint portion J6 is a torsional rotational joint about the sixth rotational axis RA6 that is arranged perpendicular to the fourth rotational axis RA4 and the fifth rotational axis RA5. By the rotation of the sixth joint portion J6, The end effector is pivoted.

  The end effector is attached to an adapter 7 provided at the lower part of 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.

  5A is a top perspective view of the arm portion 5 of FIG. 3, FIG. 5B is a plan view of the arm portion 5 of FIG. 3, and FIG. 5C is a bottom view of the arm portion 5 of FIG. . As shown in FIG. 5, the arm portion 5 is a columnar body having a constant thickness, and is configured such that the width gradually decreases toward the front. That is, the arm portion 5 is configured so that the width thereof gradually decreases toward the front. Hereinafter, the structure of the 1st, 2nd top 53 and 54 for comprising the arm part 5 shown in FIG. 5 is demonstrated.

  6A is a side view of the first frame 53 in FIG. 3, FIG. 6B is a plan view of the first frame 53 in FIG. 3, and FIG. 6C is a perspective view of the first frame 53 in FIG. FIG. 6 and FIG. 6D are top perspective views of the first frame 53 of FIG. As shown in FIG. 6A, the first frame 53 is configured to have a constant thickness (the front portion thickness T11f is the same as the rear portion thickness T11f). Also, as shown in FIG. 6B, the main body 530 of the first frame 53 is configured such that its width gradually narrows toward the front, and its shape is such that the width W11f of the front portion is the width W11r of the rear portion. A narrower trapezoidal shape.

  A pair of bearing blocks 532 are provided in front of the main body 530 in a state of extending from the edge 531. A bearing block 533 is provided between the edge portions 531 at the rear of the main body portion 530. Between the pair of bearing blocks 532 at the front end of the first frame 53, the bearing block 533 at the rear end of the other first frame 53 is fitted. A shaft hole 534 passes through the bearing block 532 at the front end in parallel with the width direction of the first frame 53. A shaft hole 535 is also passed through the bearing block 533 at the rear end in parallel with the width direction of the first frame 53. In the front and rear first frames 53, the shaft hole 535 and the shaft hole 534 communicate with each other in a state where the bearing block 533 of the front first frame 53 is inserted between the bearing blocks 532 of the rear first frame 53. A shaft is inserted into the shaft hole 535 and the shaft hole 534 that communicate with each other. The first frame 53 is connected to be able to be bent by a hinge structure including a pair of bearing blocks 532, a bearing block 533, and a shaft.

  7A is a side view of the second frame 54 in FIG. 3, FIG. 7B is a bottom view of the second frame 54 in FIG. 3, and FIG. 7C is a rear perspective view of the second frame 54 in FIG. FIG. 7 and FIG. 7D are front perspective views of the second frame 54 of FIG. The second frame 54 is formed of a bottom plate 541 and a pair of side plates 540 as a whole and has a U-shaped groove shape (a bowl shape). As shown in FIG. 7A, the side plate 540 of the second frame 54 is configured such that the height H21f of the front portion thereof is the same as the height H21r of the rear portion. In other words, the second frame 54 has a constant thickness. As shown in FIG. 7B, the bottom plate 541 of the second frame 54 is configured such that the width is gradually narrowed toward the front, and the shape of the width W21f of the front portion is narrower than the width W21r of the rear portion. It has a trapezoidal shape.

  A bearing block 543 that supports a bearing (bearing) 545 is provided between the pair of side plates 540 behind the bottom plate 541. A pair of bearing blocks 542 are provided in front of the bottom plate 541 to support the bearing 544 in a state of extending from the side plate 540. In the front and rear second pieces 54, the bearing block 543 of the rear second piece 54 is fitted between the pair of bearing blocks 542 of the front second piece 54. The bearing 544 of the bearing block 542 of the front second piece 54 communicates with the bearing 545 of the bearing block 543 of the rear second piece 54. A shaft (not shown) is inserted into the communicating bearings 544 and 545. The second frame 54 is connected to be able to be bent by a hinge structure including a pair of bearing blocks 542, a bearing block 543, and a shaft. The second frame row 52 can be bent on the inner side (the surface side of the bottom plate 541), and on the opposite side, the front and rear second frames 24 are linearly arranged so that the end surfaces of the side plates 540 are in contact with each other. Lock with.

  As described above, in order to increase the rigidity of the arm portion 5, it is necessary to firmly hold the first and second frame rows 51 and 52 in a joined state. For this purpose, the first and second frames 53 and 54 are provided with a lock mechanism for maintaining the joined state. As the locking mechanism, the first frame 53 is provided with pinhole blocks 536 protruding on both sides of the surface (back surface, inner surface) facing the second frame 54, and the second frame 54 is sandwiched between the pinhole blocks 536. A chuck block 548 and a lock pin block 546 are separately provided at the front and rear. The pinhole block 536 is a small piece having a quadrangular prism shape whose side shape is a right trapezoid whose one base angle is a right angle, and a pinhole 537 is formed along the front-rear direction.

  When the arm portion 5 is extended, the chuck block 548 and the lock pin block 546 of the front and rear second pieces 54 sandwich the pin hole block 536 of the first piece 53 from the front and rear, and project forward of the lock pin block 546. The lock pin 547 is inserted into the pinhole 537 of the pinhole block 536. As a result, the first and second frames 53 and 54 are firmly fastened and the joined state is maintained. When the arm portion 5 contracts, the second piece 54 returns to a bendable state behind the roller unit 58 and is pulled downward by gravity. On the other hand, the first frame 53 is pulled rearward by the drive gear 56 while maintaining the horizontal posture. When the second frame 54 is pulled downward and the first frame 53 is pulled rearward, the lock pin 547 of the second frame 54 is pulled out from the pin hole 537 of the first frame 53, and the second frame 54 is received by the front and rear. The part opens the pinhole block 536 of the first frame 53, whereby the joined state of the first and second frames 53 and 54 is released, and the first frame 53 and the second frame 53 are separated from each other so as to be bent.

  Under the dimensional design as described above, the arm portion 5 is configured as a columnar body whose width gradually narrows toward the front. In the linear expansion / contraction mechanism, a load due to the weight of the arm unit 5 is generated between the arm unit 5 and the roller unit 58 that supports the arm unit 5. In order to ensure the strength of the linear motion extension / contraction mechanism, the arm unit 5 can be obtained from the roller unit 58 with a support force larger than the maximum load generated between the arm unit 5 and the roller unit 58. Designed. The supporting force obtained from the roller unit 58 can be improved by increasing the contact area between the arm portion 5 and the roller unit 58. The contact area between the arm unit 5 and the roller unit 58 can be increased, for example, by increasing the width of the arm unit 5 or increasing the thickness of the arm unit 5. The width and thickness of the conventional arm portion 5 are constant, and the dimensions thereof are determined so that a supporting force larger than the maximum load generated between the arm portion 5 and the roller unit 58 can be obtained from the roller unit 58. Yes. However, the load generated between the arm unit 5 and the roller unit 58 is so small that the arm unit 5 contracts, and the width and thickness of the arm unit 5 do not necessarily have to be constant.

  Like the linear motion expansion / contraction mechanism according to the first embodiment, the first and second frames 53 and 54 are configured so that the width of the arm portion 5 gradually decreases toward the front, so that the arm portion 5 The arm weight can be reduced as compared with the conventional arm portion 5 having a constant thickness and width while securing a supporting force larger than the load due to the weight of the arm portion 5 that changes according to the extension distance. That is, according to 1st Embodiment, the arm part 5 can be reduced in weight, suppressing a strength fall in a linear motion expansion-contraction mechanism. Since the arm portion 5 can be reduced in weight, the arm portion 5 can be expected to be downsized. Further, since the arm portion 5 can be reduced in weight, the first and second frames 53 and 54 may be formed of a material having lower strength than the conventional first and second frames 53 and 54.

  In the above description, both the first and second frames 53 and 54 are configured to gradually narrow toward the front, but one of the first and second frames 53 and 54 is directed toward the front. You may make it narrow gradually.

  8 and 9, a configuration in which only the first frame 53 of the first and second frames 53 and 54 is gradually narrower toward the front will be described. 10 and 11, a configuration in which only the second frame 54 of the first and second frames 53 and 54 is gradually narrowed toward the front will be described.

  FIG. 8A is an upper perspective view of the arm unit 5 according to a modification of the first embodiment, FIG. 8B is a plan view of the arm unit 5, and FIG. 8C is a bottom view of the arm unit 5. is there. 9A is a side view showing the second frame 54 of FIG. 8, FIG. 9B is a bottom view of the second frame 54 of FIG. 8, and FIG. 9C is the rear of the second frame 54 of FIG. FIG. 9D is a front perspective view of the second frame 54 in FIG. The first frame 53 in FIG. 8 is the same in size and shape as the first frame 53 shown in FIG. Therefore, the first frame row 51 arranged in a straight line has a constant thickness and a gradually narrower width toward the front. As shown in FIG. 9 (a), each of the pair of side plates 540 has a constant height (the height H22f of the front portion is the same as the height H22r of the rear portion). Configured. As shown in FIG. 9B, the bottom plate 541 of the second frame 54 has a constant width (the front portion width W22f is the same as the rear portion width W22r). Therefore, the width and thickness of the second frame row 52 aligned in a straight line are constant. The width of the last first frame 53 of the first frame row 51 is substantially the same as the width of the last second frame 54 of the second frame row 52.

  Under the dimensional design described above, the arm portion 5 is formed in a columnar body having a constant thickness and a gradually narrowing width of the first frame row 51 toward the front, as shown in FIG. Thus, even when only the first frame 53 of the first and second frames 53 and 54 is gradually narrowed forward, the weight of the arm unit 5 that changes according to the extension distance of the arm unit 5 is determined. The arm weight can be reduced as compared with the conventional arm portion 5 having a constant thickness and width, while ensuring a supporting force larger than the load due to.

  10A is an upper perspective view of the arm unit 5 according to a modification of the first embodiment, FIG. 10B is a plan view of the arm unit 5, and FIG. 10C is a bottom view of the arm unit 5. is there. 11A is a side view showing the first frame 53 of FIG. 10, FIG. 11B is a plan view of the first frame 53 of FIG. 10, and FIG. 11C is the rear of the first frame 53 of FIG. FIG. 11D is a front perspective view of the first frame 53 of FIG. The second frame 54 in FIG. 10 is the same in size and shape as the second frame 54 shown in FIG. Therefore, the second frame row 52 arranged in a straight line has a constant thickness and a gradually narrower width toward the front. As shown in FIG. 11A, the first frame 53 is configured to have a rectangular side surface with a constant thickness (the front portion thickness T12f is the same as the rear portion thickness T12r). As shown in FIG. 11B, the first frame 53 has a constant width (the front portion width W12f is the same as the rear portion width W12r). Accordingly, the first frame row 51 arranged in a straight line has a constant width and thickness. The width of the last first frame 53 of the first frame row 51 is substantially the same as the width of the last second frame 54 of the second frame row 52.

  Under the dimensional design described above, the arm portion 5 is configured as a columnar body having a constant thickness and a gradually narrowing width of the second frame row 52 toward the front, as shown in FIG. As described above, even when only the second frame 54 of the first and second frames 53 and 54 is gradually narrowed forward, the weight of the arm unit 5 that changes according to the extension distance of the arm unit 5 is determined. The arm weight can be reduced as compared with the conventional arm portion 5 having a constant thickness and width, while ensuring a supporting force larger than the load due to.

(Second Embodiment)
In the first embodiment, the first and second frames 53 and 54 are configured so that the width of the arm portion 5 is gradually reduced. However, the first and second pieces are formed so that the width of the arm portion 5 is gradually reduced. Two frames 53 and 54 may be configured.
12A is an upper perspective view of the arm unit 5 according to the second embodiment, FIG. 12B is a plan view of the arm unit 5 according to the second embodiment, and FIG. 12C is the second embodiment. It is a bottom view of the arm part 5 which concerns. The first frame row 51 includes first frames 53a, 53b, and 53c (collectively referred to as a first frame 53). The first frames 53a and 53b have the same shape and thickness as the first frame 53 shown in FIG. 11, and the widths thereof are different from each other. The width W13 of the first frame 53a is narrower than the width W14 of the first frame 53b. A plurality of first frames 53a are arranged in the front portion of the first frame row 51, and a plurality of first frames 53b are arranged in the rear portion. The first frame 53a and the first frame 53b are connected by the first frame 53c. The structure of the first frame 53c is the same as that of the first frame 53 shown in FIG. 11, and the shape thereof is different from those of the other first frames 53a and 53b. The width of the front portion of the first frame 53c is configured to be the width W13 of the first frame 53a, and the width of the rear portion is configured to be the width W14 of the first frame 53b. The second frame row 52 includes second frames 54a and 54b (collectively referred to as the second frame 54). The second frames 54a and 54b have the same shape and thickness as the second frame 54 shown in FIG. 9, and the widths thereof are different from each other. The width W23 of the second frame 54a is narrower than the width W24 of the second frame 54b. A plurality of second frames 54a are arranged in the front portion of the second frame row 52, and a plurality of second frames 54b are arranged in the rear portion. The width W13 of the first frame 53a is the same as the width W23 of the second frame 54a, and the width W14 of the first frame 53b is the same as the width W24 of the second frame 54b.

  Under the dimensional design described above, the arm portion 5 is formed in a columnar body having a constant thickness and a stepwise narrowing toward the front as shown in FIG. In this way, by using a plurality of types of first and second frames 53 and 54 having different widths so that the width of the arm portion 5 gradually decreases toward the front, the extension distance of the arm portion 5 can be increased. The arm weight can be reduced as compared with the conventional arm portion 5 having a constant thickness and width while securing a supporting force larger than the load due to the weight of the arm portion 5 that changes accordingly. That is, according to the linear motion expansion / contraction mechanism of the second embodiment, the arm portion 5 can be reduced in weight while suppressing a decrease in strength.

  In FIG. 12, the first and second frame rows 51 and 52 are constituted by two types of frames having different widths, but one of the first and second frame rows 51 and 52 is constituted by a plurality of types of frames having different widths. May be. Each of the first and second frame rows 51 and 52 may be composed of three or more types of first and second frames 53 and 54 having different widths. Furthermore, in one of the plurality of first and second frames 53 and 54, at least one frame may be configured to be narrower than the other frames.

  FIG. 13 is an upper perspective view of the arm unit 5 according to a modification of the second embodiment. Here, one first frame 53e out of the plurality of one frame 53 is configured to be narrower than the other first frame 53d. In this way, by configuring the width of at least one of the plurality of first and second frames 53 and 54 to be narrower than the other frames, the thickness and width of the conventional arm unit 5 are constant. The arm weight can be reduced.

(Third embodiment)
In the first embodiment, the configuration of the first and second frames 53 and 54 for gradually reducing the width of the arm portion 5 has been described. However, the first portion is formed so that the thickness of the arm portion 5 is gradually reduced. The second frames 53 and 54 may be configured. FIG. 14A is an upper perspective view of the arm portion 5 of the linear motion expansion / contraction mechanism according to the third embodiment, and FIG. 14B is a side view of the arm portion 5 of FIG. 15A is a side view of the second frame 54 of FIG. 14, and FIG. 15B is a bottom view of the second frame 54 of FIG.

  In the third embodiment, the first frame 53 is configured in the same manner as the first frame 53 of the modification of the first embodiment shown in FIG. Accordingly, the width and thickness of the first frame row 51 arranged linearly are constant. As shown in FIG. 15, each of the pair of side plates 540 is configured such that the height of the second frame 54 gradually decreases toward the front, and the shape of the second frame 54 is such that the height H25f of the front portion is the height of the rear portion. Side trapezoid shape lower than the height H25r. Further, the bottom plate 541 of the second frame 54 is configured to have a constant width (the width W25f of the front portion is the same as the width W25r of the rear portion). Therefore, the width of the second frame row 52 aligned in a straight line is constant, and the thickness is gradually thinner toward the front. The width of the second frame 54 is configured to be the same as the width of the first frame 53.

  Under the dimensional design described above, the arm portion 5 is formed in a columnar body having a constant width and a gradually thinner thickness toward the front, as shown in FIG. As described above, even when the thickness of the second frame 54 is gradually reduced toward the front so that the thickness of the arm portion 5 is gradually reduced toward the front, depending on the extension distance of the arm portion 5. The arm weight can be reduced as compared with the conventional arm portion 5 having a constant thickness and width while securing a supporting force larger than the load due to the changing weight of the arm portion 5. That is, according to the linear motion extension / contraction mechanism of the third embodiment, the arm portion 5 can be reduced in weight while suppressing a decrease in strength.

  In addition, in order to make the thickness of the arm part 5 gradually thinner toward the front, the thickness of the first frame 53 may be gradually made thinner toward the front. FIG. 16A is an upper perspective view of an arm unit 5 according to a modification of the third embodiment, and FIG. 16B is a side view of the arm unit 5 according to a modification of the third embodiment. 17A is a side view of the first frame 53 of FIG. 16, and FIG. 17B is a plan view of the first frame 53 of FIG.

  The second frame 54 has the same shape and dimensions as those of the second frame 54 of the modification of the first embodiment shown in FIG. Therefore, the width and thickness of the second frame row 52 aligned in a straight line are constant. As shown in FIG. 17, the first frame 53 is configured such that the thickness is gradually reduced toward the front, and the side shape thereof is a trapezoid whose front portion thickness T15f is smaller than the rear portion thickness T15r. Further, the main body portion 531 of the first frame 53 has a constant width (the front portion width W15f is the same as the rear portion width W15r). Therefore, the width of the first frame row 51 arranged in a straight line is constant, and the thickness is gradually thinner toward the front. The width of the first frame 53 is configured to be the same as the width of the second frame 54.

  Under the dimensional design described above, the arm portion 5 is configured as a columnar body having a constant width and a progressively thinner thickness toward the front, as shown in FIG. As described above, even when the thickness of the first frame 53 is gradually reduced toward the front so that the thickness of the arm portion 5 is gradually reduced toward the front, depending on the extension distance of the arm portion 5. The arm weight can be reduced as compared with the conventional arm portion 5 having a constant thickness and width while securing a supporting force larger than the load due to the changing weight of the arm portion 5. That is, according to the linear motion expansion / contraction mechanism according to the modification of the third embodiment, the arm portion 5 can be reduced in weight while suppressing a decrease in strength.

(Fourth embodiment)
In the second embodiment, the configuration of the first and second frames 53 and 54 for reducing the width of the arm part 5 in stages has been described. However, the first part is designed so that the thickness of the arm part 5 is reduced in stages. The second frames 53 and 54 may be configured. FIG. 18A is an upper perspective view of the arm portion 5 of the linear motion expansion / contraction mechanism according to the fourth embodiment, and FIG. 18B is a side view of the arm portion 5 of FIG. In the fourth embodiment, the first frame 53 is configured in the same manner as the first frame 53 of the modification of the first embodiment shown in FIG. Accordingly, the width and thickness of the first frame row 51 arranged linearly are constant. The second frame row 52 includes second frames 54f, 54g, and 54h (collectively referred to as the second frame 54). The second frames 54f and 54g have the same shape and width as the second frame 54 shown in FIG. 9, and the side plates 540 have different heights. The height H26 of the second frame 54f is lower than the height H27 of the second frame 54g. A plurality of second frames 54f are arranged in the front portion of the second frame row 52, and a plurality of second frames 54g are arranged in the rear portion. The second frame 54f and the second frame 54g are connected by a second frame 54h. The structure of the second frame 54h is the same as that of the second frame 54 shown in FIG. 9, and the shape thereof is different from those of the other second frames 54f and 54g. In the second frame 54h, the height of the front portion of the side plate 540 is configured as the height H26 of the second frame 54f, and the height of the rear portion is configured as the height H27 of the second frame 54g. The width of the first frame 53 is the same as the width of the second frame 54.

  Under the above-described dimensional design, the arm portion 5 is formed into a columnar body having a constant width and a gradually decreasing thickness toward the front, as shown in FIG. As described above, the second frame row 52 is composed of a plurality of types of second frames 54 having different heights of the side plates 540 so that the thickness of the arm unit 5 is gradually reduced toward the front. The arm weight can be reduced as compared with the conventional arm portion 5 having a constant thickness and width while securing a supporting force larger than the load due to the own weight of the arm portion 5 that changes according to the extension distance of 5. That is, according to the linear motion extension / contraction mechanism according to the modification of the fourth embodiment, the arm portion 5 can be reduced in weight while suppressing a decrease in strength.

(Fifth embodiment)
FIG. 19A is an upper perspective view of the arm portion 5 of the linear motion expansion / contraction mechanism according to the fifth embodiment, FIG. 19B is a side view of the arm portion 5 of FIG. 19A, and FIG. FIG. 19A is a side view of the first frame row 51 in FIG. 19A, and FIG. 19D is a side view of the second frame row 52 in FIG. 19A. In the fifth embodiment, the first frame 53 has the same configuration and dimensions as the first frame 53 shown in FIG. The second frame 54 has the same structure as the second frame 54 shown in FIG. 15, and each of the pair of side plates 540 is configured to gradually increase in height toward the front, and the shape is the front The height H25f of the portion is a side trapezoidal shape higher than the height H25r of the rear portion. The change in the thickness of the first frame 53 per unit length is the same as the change in the height of the side plate 540 of the second frame 54 per unit length.

  Due to the dimensional design described above, the first frame row 51 gradually decreases in thickness toward the front, the thickness T18 of the first first frame 53 is thinner than the thickness T19 of the last first frame 53, The two-frame row 52 gradually increases in thickness toward the front, and the height H28 of the side plate 540 of the leading second frame 54 is higher than the height H29 of the side plate 540 of the trailing second frame 54. . The arm portion 5 formed by joining the first and second pieces 53 and 54 is formed into a columnar body having a constant width and thickness. As described above, even if the thickness and width of the arm portion 5 are constant, the conventional arm can be adjusted by adjusting the ratio of the thicknesses of the first and second frames 53 and 54. There is a possibility that the weight of the arm portion 5 can be reduced as compared with the portion 5.

  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.

  5... Arm part 51. First frame row 52. Second frame row 53. Second frame 54 54 Second frame 55.

Claims (18)

A plurality of first frames which are connected to each other so as to be bent at the front and rear ends;
A plurality of second pieces that are connected to each other so as to be bent at the front and rear ends of the bottom plate;
A coupling unit coupling the tops of the plurality of first frames and the tops of the plurality of second frames;
The first and second frames are supported so as to be movable back and forth, and when the first and second frames move forward, the first and second frames are joined, and the first and second frames are moved backward. A support part that separates the first and second frames when moving,
The first and second frames are rigid when the first frame is joined to the second frame, and the first and second frames return to a bent state when separated from each other.
One or both of the first and second frames gradually decrease in width toward the front, and the linear motion expansion / contraction mechanism is characterized in that   2. The linear motion expansion / contraction mechanism according to claim 1, wherein one or both of the first and second frames has a trapezoidal planar shape.   2. The linear motion expansion / contraction mechanism according to claim 1, wherein one of the first and second frames gradually decreases in width toward the front, and the other has a constant width.   The linear motion expansion / contraction mechanism according to claim 3, wherein the first frame gradually decreases in width toward the front, and the second frame has a constant width. A plurality of first frames which are connected to each other so as to be bent at the front and rear ends;
A plurality of second pieces that are connected to each other so as to be bent at the front and rear ends of the bottom plate;
A coupling unit coupling the tops of the plurality of first frames and the tops of the plurality of second frames;
The first and second frames are supported so as to be movable back and forth, and when the first and second frames move forward, the first and second frames are joined, and the first and second frames are moved backward. A support part that separates the first and second frames when moving,
The first and second frames are rigid when the first frame is joined to the second frame, and the first and second frames return to a bent state when separated from each other.
One or both of the first and second frames are at least one of which is narrower than the other, and is a linear motion expansion / contraction mechanism.   6. The linear motion expansion / contraction mechanism according to claim 5, wherein the first and second frames have a planar rectangular shape.   6. The linear motion expansion / contraction mechanism according to claim 5, wherein one or both of the first and second frames has a plurality of front widths smaller than a plurality of rear widths. A plurality of first frames which are connected to each other so as to be bent at the front and rear ends;
A plurality of second pieces that are connected to each other so as to be bent at the front and rear ends of the bottom plate;
A coupling unit coupling the tops of the plurality of first frames and the tops of the plurality of second frames;
The first and second frames are supported so as to be movable back and forth, and when the first and second frames move forward, the first and second frames are joined, and the first and second frames are moved backward. A support part that separates the first and second frames when moving,
The first and second frames are rigid when the first frame is joined to the second frame, and the first and second frames return to a bent state when separated from each other.
One or both of the first and second frames gradually decrease in thickness toward the front.   The linear motion expansion / contraction mechanism according to claim 8, wherein one or both of the first and second frames have a trapezoidal side surface.   9. The linear motion expansion / contraction mechanism according to claim 8, wherein one of the first and second frames gradually decreases in thickness toward the front, and the other has a constant thickness.   The linear motion expansion / contraction mechanism according to claim 3, wherein the first frame gradually decreases in thickness toward the front, and the second frame has a constant thickness. A plurality of first frames which are connected to each other so as to be bent at the front and rear ends;
A plurality of second pieces that are connected to each other so as to be bent at the front and rear ends of the bottom plate;
A coupling unit coupling the tops of the plurality of first frames and the tops of the plurality of second frames;
The first and second frames are supported so as to be movable back and forth, and when the first and second frames move forward, the first and second frames are joined, and the first and second frames are moved backward. A support part that separates the first and second frames when moving,
The first and second frames are rigid when the first frame is joined to the second frame, and the first and second frames return to a bent state when separated from each other.
One or both of the first and second frames are at least one of which is thinner than the other, and is a linear motion expansion / contraction mechanism.   13. The linear motion expansion / contraction mechanism according to claim 12, wherein the first and second frames have a rectangular side surface.   The linear motion expansion / contraction mechanism according to claim 12, wherein one or both of the first and second frames has a plurality of front thicknesses smaller than a plurality of rear thicknesses. A support column having a swivel rotary joint is supported on a base, and a undulation having a undulation rotary joint is placed on the support, and the undulation includes a linearly stretchable arm. The arm is equipped with a wrist that can be fitted with an end effector, and the wrist is equipped with at least one rotary joint for changing the posture of the end effector. In the robot arm mechanism,
The linear motion extension mechanism is
A plurality of first frames which are connected to each other so as to be bent at the front and rear ends;
A plurality of second pieces that are connected to each other so as to be bent at the front and rear ends of the bottom plate;
A coupling unit coupling the tops of the plurality of first frames and the tops of the plurality of second frames;
The first and second frames are supported so as to be movable back and forth, and when the first and second frames move forward, the first and second frames are joined, and the first and second frames are moved backward. A support part that separates the first and second frames when moving,
The first and second frames are rigid when the first frame is joined to the second frame, and the first and second frames return to a bent state when separated from each other.
One or both of the first and second frames gradually decrease in width toward the front. A support column having a swivel rotary joint is supported on a base, and a undulation having a undulation rotary joint is placed on the support, and the undulation includes a linearly stretchable arm. The arm is equipped with a wrist that can be fitted with an end effector, and the wrist is equipped with at least one rotary joint for changing the posture of the end effector. In the robot arm mechanism,
The linear motion extension mechanism is
A plurality of first frames which are connected to each other so as to be bent at the front and rear ends;
A plurality of second pieces that are connected to each other so as to be bent at the front and rear ends of the bottom plate;
A coupling unit coupling the tops of the plurality of first frames and the tops of the plurality of second frames;
The first and second frames are supported so as to be movable back and forth, and when the first and second frames move forward, the first and second frames are joined, and the first and second frames are moved backward. A support part that separates the first and second frames when moving,
The first and second frames are rigid when the first frame is joined to the second frame, and the first and second frames return to a bent state when separated from each other.
One or both of the first and second frames are characterized in that at least one has a narrower width than the other. A support column having a swivel rotary joint is supported on a base, and a undulation having a undulation rotary joint is placed on the support, and the undulation includes a linearly stretchable arm. The arm is equipped with a wrist that can be fitted with an end effector, and the wrist is equipped with at least one rotary joint for changing the posture of the end effector. In the robot arm mechanism,
The linear motion extension mechanism is
A plurality of first frames which are connected to each other so as to be bent at the front and rear ends;
A plurality of second pieces that are connected to each other so as to be bent at the front and rear ends of the bottom plate;
A coupling unit coupling the tops of the plurality of first frames and the tops of the plurality of second frames;
The first and second frames are supported so as to be movable back and forth, and when the first and second frames move forward, the first and second frames are joined, and the first and second frames are moved backward. A support part that separates the first and second frames when moving,
The first and second frames are rigid when the first frame is joined to the second frame, and the first and second frames return to a bent state when separated from each other.
One or both of the first and second frames gradually decrease in thickness toward the front, and the robot arm mechanism is characterized in that: A support column having a swivel rotary joint is supported on a base, and a undulation having a undulation rotary joint is placed on the support, and the undulation includes a linearly stretchable arm. The arm is equipped with a wrist that can be fitted with an end effector, and the wrist is equipped with at least one rotary joint for changing the posture of the end effector. In the robot arm mechanism,
The linear motion extension mechanism is
A plurality of first frames which are connected to each other so as to be bent at the front and rear ends;
A plurality of second pieces that are connected to each other so as to be bent at the front and rear ends of the bottom plate;
A coupling unit coupling the tops of the plurality of first frames and the tops of the plurality of second frames;
The first and second frames are supported so as to be movable back and forth, and when the first and second frames move forward, the first and second frames are joined, and the first and second frames are moved backward. A support part that separates the first and second frames when moving,
The first and second frames are rigid when the first frame is joined to the second frame, and the first and second frames return to a bent state when separated from each other.
One or both of the first and second frames are characterized in that at least one of them is thinner than the other.

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