Compliance unit

Abstract

A compliance unit 10 comprises: a body 11; a mounting plate 16; a disk 14 which is movable together with the mounting plate 16; a frame 15 which is fixed to the body 11 and accommodates the disk 14 in a movable manner; and a ball guide 13 which is disposed between the body 11 and the frame 15, accommodates steel balls 131, and guides movement of the disk 14 in an inclination direction thereof. The movement of the disk 14 in the inclination direction is guided by the steel balls 131 and the ball guide 13.

Description

Compliance Unit

[0001] The present invention relates to a compliance unit.

[0002] A conveying device such as a robot arm is used to convey an object from one position to another. Patent Document 1 discloses a compliance unit used in such a conveying device. A gripping member that grips the object is attached to the compliance unit. When the gripping member grips the object at one position or when the gripping member releases the object at another position, the compliance unit absorbs the relative positional deviation between the gripping member and each of the above positions, i.e., the positioning error.

[0003] International Publication No. 2018 / 066284

[0004] There is a demand for further miniaturization of the compliance unit that absorbs positioning errors.

[0005] In one embodiment, the compliance unit includes a main body having a cylindrical shape with a first axis as a central axis and attached to a conveying device, a mounting plate to which a gripping member for gripping a conveyed object is attached, a holding member provided between the main body and the mounting plate, having a cylindrical shape with a second axis as a central axis, to which the mounting plate is fastened and movable together with the mounting plate, an annular member provided between the mounting plate and the main body, having an opening with the first axis as a central axis and movably accommodating the holding member within the opening, a steel ball that guides or restricts movement of the holding member relative to the annular member, and a guide member provided between the main body and the annular member, having an accommodating opening for accommodating the steel ball, and guiding movement of the holding member in an inclined direction inclined with respect to the first axis. The movement of the holding member in the inclined direction is guided by the steel ball and the guide member.

[0006] According to the present invention, the compliance unit can be made smaller.

[0007] FIG. 1 is an external view of a compliance unit according to an embodiment. FIG. 2 is an exploded perspective view of the compliance unit. FIG. 3 is a cross-sectional view of the compliance unit when the mounting plate is in a reference state. FIG. 4 is a cross-sectional view of the compliance unit when the mounting plate is in a compressed state. FIG. 5 is a cross-sectional view of the compliance unit when the mounting plate moves in an inclined direction. FIG. 6 is a cross-sectional view of the compliance unit when the mounting plate moves in an inclined direction. FIG. 7 is a cross-sectional view of the compliance unit when compressed air is supplied. FIG. 8A is a transfer process diagram showing an example of a conveying device provided with a compliance unit. FIG. 8B is a transfer process diagram showing an example of a conveying device provided with a compliance unit. FIG. 8C is a transfer process diagram showing an example of a conveying device provided with a compliance unit. FIG. 8D is a transfer process diagram showing an example of a conveying device provided with a compliance unit. FIG. 8E is a transfer process diagram showing an example of a conveying device provided with a compliance unit. FIG. 8F is a transfer process diagram showing an example of a conveying device provided with a compliance unit.

[0008] Hereinafter, a compliance unit according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0009] Fig. 1 is a perspective view of the exterior of the compliance unit 10. Fig. 2 is an exploded perspective view of the compliance unit 10. Fig. 3 is a cross-sectional view of the compliance unit 10 taken along line AA shown in Fig. 1.

[0010] 1 to 3, compliance unit 10 includes a main body 11, a piston 12, a ball guide 13, a disk 14, a frame 15, and a mounting plate 16. Main body 11 is attached to a transport device 17 (see FIGS. 8A to 8F), and a gripping member 18 (see FIGS. 8A to 8F) is attached to mounting plate 16. Compliance unit 10 is used when transport device 17 transports an object placed in a component storage section, for example, to a component mounting section provided in a different position.

[0011] In the following description, the side of the compliance unit 10 that is attached to the transport device 17 may be referred to as the upper side, and the side that the gripping member 18 is attached to may be referred to as the lower side. As shown in Figures 1 to 3, the main body 11, ball guide 13, frame 15, and mounting plate 16 are arranged in this order from top to bottom.

[0012] <Main body 11> The main body 11 is formed in a cylindrical shape with a first axis X1 along the up-down direction as its central axis. As shown in Fig. 1, a plurality of mounting holes 111 are provided on an upper surface 110 of the main body 11. The mounting holes 111 are internally threaded, and the main body 11 is attached to the conveying device 17 by screw members (not shown) that are threadedly coupled to the mounting holes 111.

[0013] The main body 11 is formed with a cylinder bore 112 that has an opening on the lower side and extends in the up-down direction with the first axis X1 as its central axis. The cylinder bore 112 is a space that houses a piston 12, which will be described later. The main body 11 also has an air passage 113 that extends in a direction intersecting the first axis X1 and communicates with the cylinder bore 112. The cylinder bore 112 is a pressure chamber into which compressed air as a fluid is supplied and discharged from the outside via the air passage 113. A bolt hole 115 with an internal thread is formed in a surface 114 on the lower side of the main body 11. A bolt 20 inserted into the bolt hole 115 fastens to the main body 11.

[0014] <Piston 12> The piston 12 is housed in a cylinder bore 112 of the main body 11, which serves as a pressure chamber, so as to be movable along the first axis X1. The piston 12 is formed in a cylindrical shape with the first axis X1 as its central axis. A groove 122 is formed in an outer peripheral side surface 121 of the piston 12, extending in the circumferential direction. A seal member 123 is housed in this groove 122. When the piston 12 is housed in the cylinder bore 112, the seal member 123 abuts against a side wall surface 112a of the cylinder bore 112.

[0015] The piston 12 has an accommodation hole 125 that has an opening on the lower side and extends in the up-down direction around the first axis X1 as its central axis. The accommodation hole 125 is a space that accommodates a first elastic member 124, such as a coil spring. An upper end of the first elastic member 124 abuts against an upper inner wall surface 126 of the cylinder bore 112. A lower end of the first elastic member 124 abuts against an upper surface of a ball guide 13, which will be described later. In other words, the first elastic member 124 is disposed between the piston 12 and the ball guide 13. The piston 12 is biased upward by the first elastic member 124. In other words, the first elastic member 124 is a biasing member that biases the piston 12 in a direction away from the ball guide 13, which will be described later.

[0016] <Ball guide 13> The ball guide 13 is formed in a disk shape centered on the first axis X1. The ball guide 13 is fixed to the lower surface 114 of the main body 11 with bolts 20. Four accommodating openings 132 that accommodate steel balls 131 are formed in the ball guide 13. The accommodating openings 132 are formed on the circumference of the ball guide 13, centered on the first axis X1. The accommodating openings 132 are through holes that penetrate the ball guide 13 from the inside to the outside along the direction of the first axis X1. The inner diameter of the accommodating openings 132 is approximately equal to the diameter of the steel ball 131. Therefore, the accommodating openings 132 rotatably accommodate the steel ball 131.

[0017] The thickness (length along the first axis X1) of the ball guide 13 is smaller than the diameter of the steel ball 131. Therefore, the steel ball 131 accommodated in the accommodation opening 132 protrudes from the ball guide 13 on the upper and lower sides. The number of accommodation openings 132 is not limited to four, and a plurality of accommodation openings 132 may be formed according to the number of steel balls 131.

[0018] The thickness (length along the first axis X1) of a region 133 of the ball guide 13 near the first axis X1 is smaller than the thickness (length along the first axis X1) of a region 134 near the outer edge of the ball guide 13. A first curved surface 135 is formed on a lower surface 136 of the ball guide 13, which connects the regions 133 and 134 and is a curved surface whose thickness gradually decreases as it approaches the region 133. The first curved surface 135 is an annular region centered on the first axis X1 and including the receiving opening 132 therein.

[0019] Therefore, it can be said that the first curved surface 135 is part of a spherical surface whose center of curvature is an imaginary central point located on the first axis X1, which is the radial center of the ball guide 13, and below the ball guide 13. In other words, the first curved surface 135 is a concave surface facing upward of the compliance unit 10. By forming the first curved surface 135, the ball guide 13 functions as a guide member that guides movement of the disk 14, which will be described later, in an inclined direction inclined with respect to the first axis X1.

[0020] <Disk 14> The disk 14 is provided below the ball guide 13. The disk 14 is housed in a frame 15 (described later) and fastened to a mounting plate 16 (described later) on its lower side. In other words, the disk 14 is provided between the main body 11 and the mounting plate 16. The disk 14 has a cylindrical first disk portion 141 and a second disk portion 142 with the second axis X2 as its central axis. An accommodating hole 144 is formed in the first disk portion 141 to accommodate a second elastic member 143 such as a coil spring. The accommodating hole 144 has an opening on the upper side of the first disk portion 141, i.e., on the side facing the ball guide 13, and is a space extending along the second axis X2.

[0021] The lower end of the second elastic member 143 abuts against the bottom surface 144a of the accommodating hole 144, and the upper end abuts against the region 133 on the surface 136 of the ball guide 13. In other words, the second elastic member 143 is provided between the ball guide 13 and the disc 14. As a result, the disc 14 is biased downward by the second elastic member 143, i.e., in a direction away from the ball guide 13.

[0022] A second curved surface 145 that protrudes upward, i.e., toward the ball guide 13, which is a guide member, is formed on the upper side of the first disk portion 141, i.e., on the side facing the surface 136 of the ball guide 13. The second curved surface 145 can be said to be part of a spherical surface whose center of curvature is an imaginary central point located on the second axis X2, which is the radial center of the disk 14, and below the first disk portion 141. In other words, the second curved surface 145 is a convex surface that faces upward of the compliance unit 10.

[0023] Four holding portions 147 that hold the steel balls 131 from below are formed on the second curved surface 145. The holding portions 147 are formed on the second curved surface 145 on a circumference centered on the second axis X2. The diameter of the circumference on which the holding portions 147 are formed is approximately equal to the diameter of the circumference on which the accommodation opening 132 is formed. The holding portions 147 are recesses with tapered surfaces. The holding portions 147 widen upward so that the inner diameter gradually increases from the bottom to the top. The number of holding portions 147 is not limited to four, and multiple holding portions 147 may be formed according to the number of steel balls 131.

[0024] The second disk portion 142 is formed adjacent to the lower end of the first disk portion 141 and extends downward along the second axis X2. The second disk portion 142 has a cylindrical shape with bolt holes 148 formed therein through which bolts 21 for fastening the mounting plate 16 (described later) are inserted. In other words, the disk 14 functions as a holding member to which the mounting plate 16 (described later) is fastened. The outer diameter of the second disk portion 142 is smaller than the outer diameter of the first disk portion 141. Therefore, an end face 149 that protrudes radially outward beyond the second disk portion 142 is formed on the lower side of the first disk portion 141.

[0025] <Frame 15> The frame 15 is an annular member having an opening 151 formed therein with the first axis X1 as its central axis. The upper surface of the frame 15 abuts against an area 134 formed on a lower surface 136 of the ball guide 13. The frame 15 is fixed to the main body 11 together with the ball guide 13 by bolts 20. In other words, the ball guide 13, which is a guide member, is disposed between the main body 11 and the frame 15, which is an annular member.

[0026] The opening 151 is a through-hole that penetrates the frame 15 from the inside to the outside in the direction along the first axis X1. The opening 151 accommodates the disk 14 described above. The opening 151 is formed by a first opening 151a and a second opening 151b that have different opening diameters. In other words, the frame 15 is formed by a first annular portion 15a in which the first opening 151a is formed, and a second annular portion 15b in which the second opening 151b is formed and has an inner diameter different from that of the first annular portion 15a.

[0027] The first opening 151a is formed above the second opening 151b. The diameter of the first opening 151a formed in the first annular portion 15a is larger than the outer diameter of the first disk portion 141 of the disk 14 described above. The diameter of the second opening 151b formed in the second annular portion 15b is larger than the outer diameter of the second disk portion 142 of the disk 14 described above but smaller than the diameter of the first opening 151a. Therefore, the disk 14 is accommodated in the opening 151 with a gap S1 that allows movement in a direction intersecting (orthogonal to) the first axis X1 (hereinafter referred to as the planar direction).

[0028] A step surface 152 connecting the first annular portion 15a and the second annular portion 15b is formed at the boundary between the first opening 151a and the second opening 151b. The step surface 152 faces the end surface 149 of the disk 14 described above. As shown in FIG. 3 , when the step surface 152 and the end surface 149 of the disk 14 are in contact with each other, a gap S2 is formed between the disk 14 and the ball guide 13. Therefore, the disk 14 is accommodated in the opening 151 so as to be movable in a direction along the first axis X1 (hereinafter referred to as the up-down direction) relative to the frame 15. Note that the gap S2 is smaller than the diameter of the steel ball 131. This prevents the steel ball 131 from falling out of the accommodation opening 132.

[0029] When the disc 14 moves upward relative to the frame 15 within the opening 151 and the disc 14 comes into contact with the ball guide 13, the first curved surface 135 and the second curved surface 145 come into contact with each other. In this case, the first curved surface 135 and the second curved surface 145 slide against each other, allowing the disc 14 to be guided by the first curved surface 135 and move at an incline. That is, the disc 14 is accommodated in the opening 151 so as to be movable in a direction inclined relative to the first axis X1 (hereinafter referred to as the inclined direction). As described above, the disc 14 is also accommodated in the opening 151 so as to be movable in a planar direction. Therefore, the frame 15 can be said to be an annular member that accommodates the disc 14, which serves as a holding member, so as to be movable in directions intersecting the first axis X1 (planar direction and inclined direction).

[0030] Furthermore, since the disc 14 is not fixed to the frame 15, the disc 14 can rotate about the second axis X2. That is, the disc 14 is accommodated in the opening 151 so as to be rotatable along the rotation direction about the second axis X2.

[0031] In the direction along the first axis X1, the length of the wall surface 150 of the second opening 151b is shorter than the length of the second disk portion 142. Therefore, the vicinity of the lower end of the disk 14 housed in the opening 151 protrudes downward from the lower surface 153 of the frame 15.

[0032] A mounting hole 155 for mounting a pin 154 is formed in a surface 153 of the frame 15. When the pin 154 is mounted in the mounting hole 155, its head 154a protrudes downward from the surface 153.

[0033] <Mounting Plate 16> The mounting plate 16 is formed in a circular plate shape centered on the second axis X2. The mounting plate 16 is provided below the frame 15, facing the frame 15. In other words, the frame 15, which is an annular member, is provided between the main body 11 and the mounting plate 16. Specifically, the mounting plate 16 is fastened to the disk 14 housed in the frame 15 by bolts 21 inserted into bolt holes 161 formed with the second axis X2 as the central axis. Therefore, the mounting plate 16 is provided to be movable in the planar direction, the up-down direction, the tilt direction, and the rotation direction in accordance with the movement of the disk 14 in the planar direction, the up-down direction, the tilt direction, and the rotation direction.

[0034] As described above, the vicinity of the lower end of the disk 14 protrudes downward below the surface 153 of the frame 15. Therefore, there is a gap S3 between the mounting plate 16 fixed to the disk 14 and the frame 15. In the direction along the first axis X1, the gap S3 is larger than the above-mentioned gap S2.

[0035] Furthermore, a positioning hole 163 is formed in a lower surface 162 of the mounting plate 16 for positioning when attaching a gripping member 18 that grips the transported object. A head accommodating hole 165 is formed in an upper surface 164 of the mounting plate 16, and accommodates a head 154a of the pin 154 attached to the frame 15. The diameter of the head accommodating hole 165 is larger than the diameter of the head 154a of the pin 154. When the inner wall surface of the head accommodating hole 165 abuts against the head 154a due to rotational movement of the mounting plate 16, the movement of the mounting plate 16 in the rotational direction is restricted. In other words, the head accommodating hole 165 functions as a movement restrictor for the mounting plate 16 in the rotational direction.

[0036] <Movement of Mounting Plate 16> The cross-sectional view of Figure 3 shows a state in which compressed air is not supplied to the cylinder bore 112. In this state, a gap S2 is formed between the first curved surface 135 of the ball guide 13 and the second curved surface 145 of the disc 14. At this time, the steel ball 131 is positioned at the center point of the holding portion 147. As a result, the second axis X2 is approximately coaxial with the first axis X1. In the following explanation, the position of the mounting plate 16 when the first axis X1 and the second axis X2 are approximately coaxial may be referred to as the reference position, and the state in which the mounting plate 16 is located at the reference position may be referred to as the reference state.

[0037] Figure 4 is a cross-sectional view of the compliance unit 10 showing a case where the mounting plate 16 has moved upward from the reference state shown in Figure 3. Note that Figure 4 also shows a state where compressed air is not supplied to the cylinder hole 112. Figure 4 also shows a state where the first curved surface 135 of the ball guide 13 and the second curved surface 145 of the disk 14 are in contact. In other words, the above-mentioned gap S2 is not formed, and a gap S4 is formed between the end surface 149 and the step surface 152.

[0038] At this time, the disk 14 and mounting plate 16 are restricted from moving further upward by the ball guide 13. In other words, the disk 14 is accommodated in the frame 15 so as to be movable in the direction along the first axis X1 between the step surface 152 and the first curved surface 135. In the following description, the state in which the first curved surface 135 and the second curved surface 145 are in contact with each other as shown in FIG. 4 may be referred to as a compressed state.

[0039] As described above, because gap S3 is larger than gap S2, even in the compressed state, a gap is formed between frame 15 and mounting plate 16. Therefore, even when first curved surface 135 and second curved surface 145 are in contact with each other, mounting plate 16 and disk 14 to which mounting plate 16 is fixed can move in the planar direction, tilt direction, and rotational direction relative to frame 15.

[0040] Figure 5 is a cross-sectional view of the compliance unit 10 showing a case where the mounting plate 16 has moved (swinged) in the tilting direction from the reference state shown in Figure 3. Note that Figure 5 also shows a state where compressed air is not supplied to the cylinder hole 112. When the mounting plate 16 and the disk 14 tilt, the second axis X2 is no longer coaxial with the first axis X1, but is tilted relative to the first axis X1.

[0041] 5, tilting of the disk 14 causes a portion of the second curved surface 145 to move upward by the distance of the gap S2. As a result, a portion of the second curved surface 145a comes into contact with a portion of the first curved surface 135 (the first curved surface 135a), and the remaining portion of the second curved surface 145 does not come into contact with the remaining portion of the first curved surface 135. As described above, since the gap S3 is larger than the gap S2, even when the mounting plate 16 is tilted, the gap S3 is formed between the frame 15 and the mounting plate 16. Therefore, even when the mounting plate 16 is tilted, the mounting plate 16 and the disk 14 to which the mounting plate 16 is fixed can move in the rotational direction.

[0042] Figure 6 is a cross-sectional view of the compliance unit 10 showing a case where the mounting plate 16 has moved (swinged) in a tilting direction from the compressed state shown in Figure 4. Note that Figure 6 also shows a state where compressed air is not being supplied to the cylinder hole 112. When the mounting plate 16 and the disk 14 tilt, the second axis X2 is no longer coaxial with the first axis X1, but is tilted relative to the first axis X1.

[0043] Because the first curved surface 135 and the second curved surface 145 are already in contact, the second curved surface 145 slides relative to the first curved surface 135 as the disc 14 tilts. At this time, as the second curved surface 145 slides along the first curved surface 135, the steel ball 131 rotating in the accommodation opening 132 is positioned on the slope of the holding portion 147, which is a tapered recess. In other words, the disc 14, which is a holding member, moves in the tilting direction, guided by the steel ball 131 and the ball guide 13, which is a guiding member. It can also be said that the steel ball 131 guides the movement of the disc 14 relative to the frame 15, which is an annular member.

[0044] As described above, since gap S3 is larger than gap S2, a gap is also formed between frame 15 and mounting plate 16. That is, even in the state shown in Figure 6, mounting plate 16 and disk 14 to which mounting plate 16 is fixed can move in the rotation direction.

[0045] When the force moving the mounting plate 16 no longer acts on the mounting plate 16, the biasing force of the second elastic member 143 causes the disk 14 and the mounting plate 16 to return from the state shown in Figures 4 to 6 to the reference position shown in Figure 3.

[0046] FIG. 7 is a cross-sectional view of the compliance unit 10 showing a state in which compressed air is supplied to the cylinder bore 112 from the state shown in FIGS. 3 to 6 . When compressed air is supplied to the cylinder bore 112 via the air passage 113, the pressure within the cylinder bore 112 increases, causing the piston 12 to move downward against the biasing force of the first elastic member 124. As the piston 12 moves downward, the lower end surface 127 of the piston 12 comes into contact with the steel ball 131, thereby stopping the movement of the piston 12. The steel ball 131 that has come into contact with the piston 12 is pressed by the piston 12 and positioned at the center point of the retaining portion 147. As described above, the diameter of the circumference on which the retaining portion 147 is formed and the diameter of the circumference on which the accommodation opening 132 is formed are approximately equal, so when the steel ball 131 is positioned at the center point of the retaining portion 147, the first axis X1 and the second axis X2 are approximately coaxial.

[0047] The pressure in the cylinder bore 112 is transmitted to the disk 14 via the steel ball 131. This presses the end surface 149 of the disk 14 against the stepped surface 152 of the frame 15, forming a gap S2 between the first curved surface 135 and the second curved surface 145. This restricts movement of the disk 14 in the up-down, planar, tilted, and rotational directions. That is, the movement of the disk 14 relative to the frame 15 in directions intersecting and along the first axis X1 is restricted by the steel ball 131 pressed by the piston 12 and the frame 15, which is an annular member. The disk 14 is held (locked) at a reference position where the first axis X1 and the second axis X2 are substantially coaxial (locked state). It can also be said that the steel ball 131 restricts movement of the disk 14, which is a holding member, relative to the frame 15, which is an annular member. As a result, the mounting plate 16 is restricted from moving in the up-down direction, the horizontal direction, the tilt direction, and the rotation direction, and is also locked at the reference position.

[0048] On the other hand, when compressed air is exhausted from the cylinder bore 112, the piston 12 moves upward due to the biasing force of the first elastic member 124. That is, when compressed air is not supplied to the cylinder bore 112, which serves as a pressure chamber, the first elastic member 124 moves the piston 12 along the first axis X1 in a direction away from the ball guide 13. As a result, the end face 127 of the piston 12 moves away from the steel ball 131, and the force pressing the end face 149 of the disk 14 against the stepped surface 152 no longer acts. As a result, the state in which the mounting plate 16 was locked in the reference position is released. As a result, the mounting plate 16 returns to the reference state shown in FIG. 3 and becomes movable in the up-down direction, horizontal direction, tilt direction, and rotational direction.

[0049] 8A to 8F are transport process diagrams showing an example of a transport device 17 provided with the compliance unit 10. A gripping member 18 that grips the transported object W is attached to the transport device 17 via the compliance unit 10. 8A to 8F show processes when the transport device 17 transports, for example, the transported object W placed in the component storage section 30 to the component mounting section 31.

[0050] 8A shows a state in which the transport device 17 approaches the transported object W placed in the accommodation hole 32 of the component accommodation unit 30. As shown in Fig. 8A, the transported object W is placed in the accommodation hole 32 with its central axis P, i.e., the central axis for positioning, tilted.

[0051] Figure 8B shows a state in which the transport device 17 has moved downward from the state shown in Figure 8A toward the transported object W, and the gripping members 18 have approached the transported object W. Figure 8C shows a state in which the transported object W has been gripped by the gripping members 18 in the state shown in Figure 8B. Because the central axis P is inclined with respect to the first axis X1, the mounting plate 16 moves at an angle so that the second axis X2 becomes coaxial with the central axis P in response to the gripping of the transported object W by the gripping members 18. In other words, the mounting plate 16 and the disk 14 are in the state shown in Figure 5.

[0052] 8D shows a state in which the transport device 17 has moved away from the component storage section 30 and the transported object W has been removed from the component storage section 30. With the transported object W removed from the storage hole 32, fluid (compressed air) is supplied from the outside to the cylinder hole 112. As a result, the compliance unit 10 enters a locked state in which the piston 12 presses the steel ball 131 and the disk 14 is pressed against the frame 15. In other words, the mounting plate 16 is locked at the reference position. In this state, the transport device 17 transports the transported object W to the component mounting section 31.

[0053] 8E shows a state in which the transport device 17 moves downward and the transported object W approaches the accommodation hole 33 of the component mounting unit 31. When the transported object W approaches the accommodation hole 33, the compressed air in the cylinder hole 112 is discharged to the outside, and the locked state of the mounting plate 16 is released. In other words, the mounting plate 16 returns to the reference state shown in FIG. 8E also shows a case in which the central axis Q of the accommodation hole 33, i.e., the central axis for positioning, is inclined with respect to the first axis X1.

[0054] When the lower part of the transported load W comes into contact with the accommodation hole 33, the mounting plate 16 approaches the frame 15 along the direction of the first axis X1. As the mounting plate 16 moves, the disk 14 also moves along the direction of the first axis X1, as described above. Then, as shown in FIG. 4 , the first curved surface 135 and the second curved surface 145 come into contact with each other, and the disk 14 enters a compressed state in which upward movement thereof is restricted.

[0055] 8F shows the state in which the transport device 17 shown in FIG. 8E has been inserted into the component mounting section 31. As described above, the first axis X1 is inclined with respect to the central axis Q. Therefore, the mounting plate 16 moves in an inclined direction with respect to the frame 15, and the second curved surface 145 of the disk 14 slides against the first curved surface 135. As a result, the state shown in FIG. 6 is reached, and in this state, the transported object W is inserted into the storage hole 33 and positioned. Then, the gripping member 18 moves downward, inserting the transported object W into the storage hole 33.

[0056] When the cross section of the transported object W is rectangular and the accommodation hole 33 is a rectangular hole, if the transported object W is misaligned in the rotational direction with respect to the rectangular hole, the mounting plate 16 moves in the rotational direction about the first axis X1, thereby allowing the transport device 17 to insert the transported object W into the rectangular hole.

[0057] According to the above-described embodiment, at least one of the following advantageous effects can be obtained.

[0058] (1) The compliance unit 10 includes a ball guide 13, a disk 14, and a frame 15. The disk 14, which has a cylindrical shape with the second axis X2 as its central axis, is housed in an opening 151 of the frame 15 so as to be movable together with a fastened mounting plate 16. The ball guide 13 is disposed between the main body 11 and the frame 15, and houses a steel ball 131 that guides or restricts movement of the disk 14 relative to the frame 15, and also guides movement of the disk 14 in the tilting direction.

[0059] As a result, the movement of the mounting plate 16 is restricted and guided by the disk 14, which is a single member housed in the frame 15 attached below the main body 11. As a result, the radial size of the compliance unit 10 can be reduced compared to a comparative compliance unit configured in such a way that the member that restricts the movement of the mounting plate 16 and the member that guides it are separate members and arranged along the radial direction of the main body 11. As a result, by arranging multiple compliance units 10 at an extremely narrow pitch on one conveying device 17, it becomes possible to transport multiple transported objects W with one conveying device 17. Furthermore, it becomes possible to reduce the size of the conveying device 17 compared to the case in which multiple compliance units of the comparative example are arranged to transport multiple transported objects W.

[0060] Furthermore, the steel ball 131 is held and the movement of the disc 14 in the tilt direction is guided by the ball guide 13, which is a single member. At this time, the steel ball 131 is accommodated in an accommodating opening 132, which is a through hole formed in the ball guide 13. Therefore, the ball guide 13 and the steel ball 131 are disposed at the same position in the vertical direction, and it is possible to reduce the size of the compliance unit 10 in the vertical direction (the direction along the first axis X1).

[0061] (2) A first curved surface 135 is formed on a surface 136 of the ball guide 13 facing the disk 14. The first curved surface 135 is recessed about the first axis X1 in a direction away from the disk 14. A second curved surface 145 is formed on the side of the disk 14 facing the ball guide 13 and protrudes toward the ball guide 13 about the second axis X2. The second curved surface 145 slides against the first curved surface 135, thereby guiding the movement of the disk 14 in the tilting direction. This allows the mounting plate 16 attached to the disk 14 to swing in accordance with the movement of the disk 14 in the tilting direction.

[0062] (3) The second curved surface 145 is formed with a holding portion 147, which is a tapered recess that holds the steel ball 131 housed in the housing opening 132. This allows the steel ball 131 to be held without falling out, and also allows the disk 14 to move while being guided by the rotation of the steel ball 131.

[0063] (4) The disk 14 is housed between the stepped surface 152 formed on the frame 15 and the first curved surface 135 so as to be movable in the direction along the first axis X1. This allows the disk 14, which is a single member housed in the frame 15 attached below the main body 11, to restrict and guide the movement of the mounting plate 16 along the first axis X1.

[0064] (5) The inner diameter of the first annular portion 15a of the frame 15 is larger than the outer diameter of the disk 14. This allows the disk 14 to move within the opening 151 in a direction (planar direction) intersecting (perpendicular to) the first axis X1.

[0065] (6) The second elastic member 143 is provided between the disk 14 and the ball guide 13 and biases the disk 14 in a direction away from the ball guide 13. As a result, when no external force is applied to the disk 14 via the mounting plate 16, the biasing force can position the disk 14 at a reference position where the first axis X1 and the second axis X2 are substantially coaxial.

[0066] (7) The first elastic member 124, which is a biasing member, is disposed between the piston 12 and the ball guide 13 and biases the piston 12 in a direction (upward) away from the ball guide 13. When compressed air is supplied to the cylinder bore 112, which is a pressure chamber, the piston 12 moves along the first axis X1 toward the ball guide 13 against the biasing force of the first elastic member 124 and presses the steel ball 131. This causes the mounting plate 16 to enter a locked state in which it is locked at the reference position, as described above. Furthermore, when compressed air is not supplied to the cylinder bore 112, the piston 12 moves along the first axis X1 away from the ball guide 13 due to the biasing force of the first elastic member 124. This releases the mounting plate 16 from the locked state, as described above. As a result, the first elastic member 124 included in the member that switches the mounting plate 16 between a locked state and an unlocked state can also be arranged along the first axis X1, which contributes to preventing the compliance unit 10 from becoming larger in the radial direction.

[0067] Although various embodiments have been described above, the present invention is not limited to these. Other embodiments that are conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0068] Although the compliance unit 10 of the embodiment includes the first elastic member 124, which is a biasing member, it may not include the first elastic member 124. In this case, the compliance unit 10 may not include the piston 12 biased by the first elastic member 124 or the seal member 123 provided on the piston 12. Furthermore, the main body 11 does not have a cylinder hole 112 for accommodating the piston 12. That is, the compliance unit 10 does not have a pressure chamber and is not supplied with compressed air. Furthermore, the compliance unit 10 does not have a configuration in which the piston 12 presses the steel ball 131. In this case, the compliance unit 10 does not enter a locked state in which the mounting plate 16 is locked in the reference position, as shown in FIG. 8D . However, even when compressed air is not supplied, the disc 14 is guided in its tilting direction by the steel ball 131 and the ball guide 13 in which the steel ball 131 is accommodated, as in the embodiment. As a result, the same effects (1) to (6) as those obtained by the embodiment can be obtained.

[0069] REFERENCE SIGNS LIST 10 Compliance unit, 11 Main body, 12 Piston, 13 Ball guide, 14 Disk, 15 Frame, 15a First annular portion, 15b Second annular portion, 16 Mounting plate, 17 Conveying device, 18 Grip member, 112 Cylinder hole, 124 First elastic member, 131 Steel ball, 132 Storage opening, 135 First curved surface, 143 Second elastic member, 145 Second curved surface, 147 Holding portion, 151 Opening, 152 Step surface, X1 First axis, X2 Second axis

Claims

a mounting plate to which a gripping member for gripping a transported object is attached; a holding member provided between said main body and the mounting plate, having a cylindrical shape with a second axis as its central axis, to which said mounting plate is fastened and movable together with said mounting plate; an annular member provided between the mounting plate and said main body, having an opening with the first axis as its central axis and movably accommodating the holding member within said opening; a steel ball that guides or restricts movement of the holding member relative to the annular member; and a guide member provided between said main body and the annular member, having an accommodating opening for accommodating the steel ball, and guiding movement of the holding member in an inclined direction inclined with respect to the first axis, wherein movement of the holding member in the inclined direction is guided by the steel ball and the guide member.

2. A compliance unit as described in claim 1, wherein a first curved surface is formed on the surface of the guide member facing the holding member, the first curved surface being concave in a direction away from the holding member and centered on the first axis, and a second curved surface is formed on the surface of the holding member facing the guide member, the second curved surface being centered on the second axis and protruding toward the guide member, and the second curved surface slides against the first curved surface to guide the movement of the holding member in the inclined direction.

3. A compliance unit according to claim 2, wherein the second curved surface is formed with a retaining portion which is a tapered recess for retaining the steel ball accommodated in the accommodation opening.

4. A compliance unit as described in claim 3, wherein the annular member is formed with a first annular portion and a second annular portion having different inner diameters formed along the first axis, and a step surface connecting the first annular portion and the second annular portion, and the retaining member is accommodated within the annular member between the step surface and the first curved surface and movable in a direction along the first axis.

5. A compliance unit according to claim 4, wherein the inner diameter of the first annular portion is larger than the outer diameter of the holding member.

6. A compliance unit according to claim 5, further comprising an elastic member provided between said holding member and said guide member, said elastic member biasing said holding member in a direction away from said guide member.

7. A compliance unit as described in claim 6, wherein the main body portion is provided with a pressure chamber having the first axis as its central axis, and a piston is disposed within the pressure chamber so as to be movable in a direction along the first axis, and when no fluid is supplied to the pressure chamber, the movement of the retaining member in the inclined direction is guided by the steel ball and the guide member, and when fluid is supplied to the pressure chamber, the movement of the retaining member relative to the annular member is restricted by the steel ball pressed by the piston and the annular member, and the retaining member is held in a position where the first axis and the second axis are coaxial.

8. A compliance unit as described in claim 7, further comprising a biasing member disposed between the piston and the guide member and biasing the piston in a direction away from the guide member, wherein when no fluid is supplied to the pressure chamber, the piston moves along the first axis in a direction away from the guide member due to the biasing force of the biasing member, and when fluid is supplied to the pressure chamber, the piston moves along the first axis towards the guide member against the biasing force of the biasing member and presses the steel ball.

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