Magnet gripper and industrial robot

Abstract

A magnet gripper (14) comprises: a first gripper unit (16) having a first magnet (28) magnetized in the diameter direction; a second gripper unit (16A) having a second magnet (28A) magnetized in the diameter direction; and a rotating shaft (20) that connects the first magnet (28) and the second magnet (28A) so as cause the magnets to rotate around the rotational axis of the rotating shaft. The second gripper unit (16A) is disposed so as to be separated by a distance such that the second gripper is not affected by the adsorption force of the first gripper unit (16).

Description

Magnetic grippers and industrial robots

[0001] The present disclosure relates to a magnetic gripper and an industrial robot.

[0002] Magnetic grippers are used to transport magnetic workpieces such as steel plates. For example, International Publication No. 2018 / 200948 describes a magnetic gripper that attracts or releases a workpiece by the rotational movement of a magnet.

[0003] When transporting a large workpiece, even if the magnetic gripper has enough adhesive power to lift the weight of the workpiece, the workpiece can easily come off when force is applied to the edge, etc. Also, if a single magnetic gripper tries to forcefully attach a large workpiece, it may deform the workpiece or vibrate during transport, making stable transport impossible.

[0004] To avoid the above problems, it has been considered to use multiple magnetic grippers. However, when multiple magnetic grippers are used, electromagnetic actuators or electric motors are required to drive the magnets. In this case, drive circuits are required to drive the multiple electromagnetic actuators or electric motors, respectively, which increases the cost of the device. Furthermore, when multiple drive circuits are integrated using a communication line such as industrial Ethernet, the system configuration becomes more complex.

[0005] The present disclosure aims to solve the above-mentioned problems.

[0006] A first aspect of the present disclosure is a magnetic gripper comprising a first gripper unit having a first magnet magnetized in a diameter direction perpendicular to a rotation axis parallel to an attraction surface, a second gripper unit having a second magnet magnetized in a diameter direction perpendicular to the rotation axis, and a rotating shaft connecting the first magnet and the second magnet and rotating the first magnet and the second magnet around the rotation axis, wherein the first gripper unit and the second gripper unit are positioned at a distance apart such that the attraction forces due to the magnetic force of the first magnet and the attraction forces due to the magnetic force of the second magnet do not affect each other.

[0007] A second aspect of the present disclosure is an industrial robot including the magnetic gripper according to the first aspect and a robot arm that holds and drives the magnetic gripper.

[0008] The magnetic gripper and industrial robot disclosed herein can stably transport large workpieces while suppressing increases in weight and reducing equipment costs.

[0009] FIG. 1 is a perspective view of an industrial robot according to a first embodiment. FIG. 2 is a cross-sectional view of a magnetic gripper according to the first embodiment. FIG. 3A is a perspective view of a first gripper unit of FIG. 1, and FIG. 3B is a perspective view of a second gripper unit of FIG. 1. FIG. 4A is an explanatory diagram showing the flow of magnetic flux in an attracted state of the first gripper unit and the second gripper unit. FIG. 4B is an explanatory diagram of a release operation in which the first gripper unit and the second gripper unit release the attraction of a workpiece. FIG. 4C is an explanatory diagram of a demagnetization operation in which the first gripper unit and the second gripper unit demagnetize a workpiece. FIG. 5 is an explanatory diagram of an attracted state of a workpiece by the magnetic gripper of FIG. 1. FIG. 6 is an explanatory diagram of an attracted state of a workpiece by a magnetic gripper according to a comparative example. FIG. 7 is a cross-sectional view of a magnetic gripper according to a second embodiment. FIG. 8A is a cross-sectional view of a first gripper unit according to a third embodiment in an attracted state, and FIG. 8B is a cross-sectional view of the first gripper unit of FIG. 8A in a released state. FIG. 9 is a cross-sectional view of a magnetic gripper according to a fourth embodiment.

[0010] First Embodiment As shown in Fig. 1, an industrial robot 10 according to this embodiment includes a multi-axis, multi-joint robot arm 12 that is movable at multiple joints 12a, and a magnetic gripper 14 attached to the tip of the robot arm 12. This industrial robot 10 is used, for example, on a production line in an automobile factory to transport magnetic workpieces W, such as steel plates and various parts. The magnetic gripper 14 in Fig. 1 shows one form of a shape that is suitable for attracting a thin plate-like workpiece W.

[0011] 2, the magnetic gripper 14 includes a first gripper unit 16, a second gripper unit 16A, a rotating shaft 20, a drive mechanism 22, and an intermediate housing 24. The magnetic gripper 14 attracts and holds the workpiece W at two locations, the first gripper unit 16 and the second gripper unit 16A. The first gripper unit 16 and the second gripper unit 16A are spaced apart from each other at a distance such that their magnetic forces (attractive forces) do not substantially affect each other. In the following description, in order to clarify the shapes and positional relationships of the components, the terms axial direction, width direction, and attraction direction are used to indicate three mutually orthogonal directions.

[0012] The axial direction is a direction parallel to the surface of the workpiece W and a direction parallel to the rotation axis of the magnet and the rotating shaft 20. The width direction is a direction parallel to the surface of the workpiece W and perpendicular to the rotation axis and the rotating shaft 20 (a direction perpendicular to the paper surface in FIG. 2). The attraction direction is a direction perpendicular to the rotation axis and the rotating shaft 20 and perpendicular to the surface of the workpiece W. Note that, in the attraction direction, the direction approaching the workpiece W is referred to as "down," and the direction away from the workpiece W is referred to as "up." Note that the terms "up" and "down" are used to explain the positional relationship of the components of the magnetic gripper 14, and do not limit the arrangement direction of the magnetic gripper 14.

[0013] The first gripper unit 16 includes a first yoke 26, a first magnet 28, and a pair of pole pieces 30. The first yoke 26 is made of a magnetic material with high magnetic permeability. The first yoke 26 has a first end face 26a in a first axial direction and a second end face 26b in a second axial direction. The first end face 26a and the second end face 26b are formed by planes perpendicular to the axial direction. The first yoke 26 also has a lower face 26c located on the workpiece side in the attracting direction and an upper face 26d located on the opposite side of the attracting direction. The lower face 26c and the upper face 26d are formed by planes perpendicular to the attracting direction. Furthermore, as shown in FIG. 3A , the first yoke 26 has a first side portion 26e on one side in the width direction and a second side portion 26f on the other side in the width direction.

[0014] A recess 26g is formed in a first side portion 26e of the first yoke 26, and a recess 26h is formed in a second side portion 26f of the first yoke 26. Pole pieces 30 are fitted and fixed in the recesses 26g and 26h, respectively.

[0015] The pole pieces 30 are plate-shaped members made of a magnetic material with high magnetic permeability. The lower ends of the pole pieces 30 protrude further toward the workpiece W than the lower surface 26c of the first yoke 26. The pair of pole pieces 30 abut against the workpiece W to transmit the magnetic flux of the first magnet 28 to the workpiece W. The lower ends of the pole pieces 30 are arranged along a predetermined plane (attraction surface). The attraction surface is parallel to the axial direction and perpendicular to the attraction direction. The pole pieces 30 are removably fixed to the first yoke 26 with removable fastening members such as screws or bolts (not shown). Therefore, the pole pieces 30 are replaceable, and can be replaced if their shape changes due to wear or the like.

[0016] The first yoke 26 has a housing chamber 34 at its center in the width direction and the attraction direction. The housing chamber 34 is circular when viewed in the axial direction. The housing chamber 34 extends in the axial direction, penetrating from the first end face 26a to the second end face 26b. The housing chamber 34 houses the first magnet 28. The inner circumferential surface of the housing chamber 34 is located outside the rotation radius of the first magnet 28, and therefore does not interfere with the rotational displacement of the first magnet 28.

[0017] The first yoke 26 further has an air gap 36. The air gap 36 is located at the center of the first yoke 26 in the width direction. The air gap 36 is a portion of the first yoke 26 through which magnetic flux has difficulty passing, and prevents magnetic flux from passing in the width direction of the first yoke 26. The air gap 36 prevents a short circuit in the magnetic circuit through the first yoke 26 when the pair of magnetic poles of the first magnet 28 are oriented in the width direction, and directs the magnetic flux toward the pole piece 30.

[0018] In this embodiment, the air gap portion 36 has a first groove 36a and a second groove 36b. The first groove 36a is located below the accommodating chamber 34, faces the accommodating chamber 34, and extends in the axial direction. The first groove 36a has a semicircular cross-sectional shape when viewed in the axial direction. The second groove 36b is located above the accommodating chamber 34, faces the accommodating chamber 34, and extends in the axial direction. The second groove 36b has a semicircular cross-sectional shape when viewed in the axial direction. Note that the shapes of the first groove 36a and the second groove 36b are not limited to semicircular shapes, and any appropriate shape can be selected as long as they can provide resistance to the passage of magnetic flux passing through the first yoke 26 in the width direction.

[0019] In the air gap 36, the groove is filled with air, which has low magnetic permeability, reducing the cross-sectional area of ​​the magnetic material through which magnetic flux passes. However, the first yoke 26 of this embodiment is not completely divided by the air gap 36, but is instead integrally connected by a thin magnetic wall. With this configuration, the accommodation chamber 34 does not open to the lower surface 26c or the upper surface 26d, and is isolated from the outside in an airtight and liquid-tight manner. This structure makes it easy to prevent water and dust from entering the accommodation chamber 34. The air gap 36 may be formed on the lower surface 26c and the upper surface 26d. In this case, the accommodation chamber 34 does not need to have a groove. Alternatively, the air gap 36 may be formed as a through-hole penetrating in the axial direction, formed between the lower surface 26c and the accommodation chamber 34 and between the upper surface 26d and the accommodation chamber 34.

[0020] The first magnet 28 has a plurality of disk-shaped magnet pieces 28a. The plurality of magnet pieces 28a are arranged at predetermined intervals in the axial direction and are fixed to one another in the axial direction via the rotating shaft 20 to form the first magnet 28. Each magnet piece 28a is magnetized in the diametric direction so that the center of the north pole is at the same position in the circumferential direction (same angle in the rotational direction). Arranging the magnet pieces 28a at intervals in the axial direction spreads the magnetic flux, allowing an attractive force to be generated over a relatively wide area, so that a large workpiece W can be attracted with a relatively small number of magnets. Note that if the workpiece W is thick and heavy, the first magnet 28 may be configured so that the plurality of magnet pieces 28a are closely packed in the axial direction to generate a stronger magnetic flux density.

[0021] In the illustrated example of the first magnet 28, the rotating shaft 20 is used to connect the multiple magnet pieces 28a, but this embodiment is not limited to this. The first magnet 28 may be configured by connecting the multiple magnet pieces 28a using a separate member such as a rod, frame, or disk that can be connected to the rotating shaft 20. The first magnet 28 may also be configured by a single cylindrical magnet piece 28a that extends long in the axial direction.

[0022] 2 and 3B, the second gripper unit 16A has a second yoke 26A, a second magnet 28A, a pole piece 30, and an air gap 36A. The second yoke 26A, the second magnet 28A, the pole piece 30, and the air gap 36A are formed to have the same shapes and dimensions as the first yoke 26, the first magnet 28, the pole piece 30, and the air gap 36, respectively, of the first gripper unit 16. In the configuration of the second gripper unit 16A, a description of the same configuration as the first gripper unit 16 will be omitted.

[0023] The circumferential center position (rotational angle) of the N pole of the second magnet 28A is the same as the circumferential center position (rotational angle) of the N pole of the first magnet 28. Furthermore, the circumferential center position of the S pole of the second magnet 28A is the same as the circumferential center position of the S pole of the first magnet 28. Note that the circumferential center position of the N pole of the second magnet 28A may be 180° different from the circumferential center position of the N pole of the first magnet 28.

[0024] The second gripper unit 16A is separated from the first gripper unit 16 by a distance that does not substantially reach the magnetic force of the first magnet 28 of the first gripper unit 16. Here, the distance that does not substantially reach the magnetic force of the first magnet 28 is a distance that does not cause magnetic coupling or a magnetic circuit to the extent that the magnetic flux of the first magnet 28 affects the attraction force between the second gripper unit 16A and each member of the second gripper unit 16A.

[0025] The distance between the first gripper unit 16 and the second gripper unit 16A is set depending on the dimensions of the workpiece W to be gripped. In one aspect, the axial center of the second gripper unit 16A and the axial center of the first gripper unit 16 are disposed with the center of gravity of the workpiece W in between. In this case, the distance between the axial center of the first gripper unit 16 and the axial center of the second gripper unit 16A can be set to ⅓ or more, more preferably ½ or more, and even more preferably ⅔ or more of the longitudinal dimension of the workpiece W. The first gripper unit 16 and the second gripper unit 16A disposed in this manner can stably transport the thin plate-like workpiece W without deforming or vibrating it.

[0026] As shown in Fig. 2, the rotating shaft 20 extends in the axial direction along the rotation axis. In this embodiment, the rotating shaft 20 passes through the first magnet 28 and the second magnet 28A in the axial direction. The rotating shaft 20 is connected to the first magnet 28 and the second magnet 28A, and the first magnet 28 and the second magnet 28A rotate integrally with the rotating shaft 20. One axial end 20a of the rotating shaft 20 protrudes from the first magnet 28. A drive mechanism 22 is connected to the end 20a of the rotating shaft 20.

[0027] The drive mechanism 22 is connected to the rotary shaft 20 and rotates the rotary shaft 20 about its rotation axis. The drive mechanism 22 includes a drive motor 38 and a transmission mechanism 40. The drive motor 38 is attached to the first yoke 26 of the first gripper unit 16. The transmission mechanism 40 includes, for example, pulleys 40a and 40b and a belt 40c. The pulley 40a is connected to the drive shaft 38a of the drive motor 38, and the pulley 40b is connected to the rotary shaft 20. The belt 40c is stretched between the pulleys 40a and 40b and transmits the rotation of the drive shaft 38a of the drive motor 38 to the rotary shaft 20. The transmission mechanism 40 may be configured with a sprocket and a chain, or may be configured with a coaxial coupling mechanism using gears or a coupling.

[0028] The magnetic gripper 14 of this embodiment is configured as described above. In the illustrated example, the storage chambers 34, 34A are open at the ends of the first gripper unit 16 and the second gripper unit 16A, but the storage chambers 34, 34A may be sealed liquid-tight and airtight with end caps (not shown). This configuration provides high waterproof performance.

[0029] The operation of the magnetic gripper 14 will now be described.

[0030] 4A to 5, under the control of a control device (not shown), the magnetic gripper 14 rotates the rotary shaft 20 via the drive mechanism 22 to attract and release the workpiece W. When attracting the workpiece W, as shown in Fig. 4A, the first magnet 28 of the first gripper unit 16 is rotated so that the north and south poles (magnetization direction) of the first magnet 28 face the width direction. At this time, the north and south poles of the second magnet 28A of the second gripper unit 16A also face the width direction.

[0031] As shown in the figure, magnetic field lines flowing out from the magnetic pole of the first magnet 28 flow into the first yoke 26. Because the first yoke 26 is magnetically divided in the width direction by the air gap portion 36, most of the magnetic flux is directed toward the pole piece 30 and is emitted from the lower end of the pole piece 30. The magnetic flux emitted from the pole piece 30 flows through the magnetic workpiece W. This causes the workpiece W to be attracted to the first gripper unit 16. Similarly, in the second gripper unit 16A, most of the magnetic field lines of the second magnet 28A flow through the workpiece W, and the second gripper unit 16A attracts the workpiece W.

[0032] 4B , when the pair of magnetic poles of the first magnet 28 (second magnet 28A) of the magnetic gripper 14 are oriented in the attracting direction, the magnetic field lines of the first magnet 28 (second magnet 28A) are short-circuited inside the first yoke 26 (second yoke 26A). This prevents the magnetic field from leaking to the pair of pole pieces 30, reducing the attractive force on the workpiece W. As a result, the magnetic gripper 14 releases its attraction to the workpiece W.

[0033] Depending on the magnetic characteristics of the workpiece W, magnetization due to the magnetic field generated when the workpiece W was attracted may remain, and simply placing the workpiece W in the position shown in Fig. 4B may not release the attraction of the workpiece W. In such cases, the drive mechanism 22 rotates the first magnet 28 (second magnet 28A) from the position shown in Fig. 4B to the position shown in Fig. 4C. In the position shown in Fig. 4C, a weak magnetic field in the opposite direction to that in Fig. 4A is emitted from the pair of pole pieces 30, demagnetizing the workpiece W. This allows the magnetic gripper 14 to release the attraction of the workpiece W even if the workpiece W is magnetized.

[0034] For example, when a paint containing magnetic flakes is applied to the workpiece W, it is desirable to further reduce the residual magnetization of the workpiece W. In this case, demagnetization by the magnetic gripper 14 is performed by reciprocating (rotating) the first magnet 28 and the second magnet 28A between angles +θ and −θ around a rotation angle θ=90°, at which the magnetic poles of the first magnet 28 and the second magnet 28A face the attraction direction. During this operation, the first magnet 28 and the second magnet 28A are operated so that the absolute value of the rotation angle θ gradually approaches 0 and are finally stopped at an angle of 90°. This demagnetization operation gradually reduces the magnetization direction of the workpiece W while repeatedly reversing it multiple times, ultimately reducing the residual magnetization of the workpiece W to an extremely small value. The magnetic gripper 14 does not require a demagnetizing electromagnetic coil and can be demagnetized simply by rotating the first magnet 28 and the second magnet 28A.

[0035] The magnetic gripper 100 shown in the comparative example in Fig. 6 includes one gripper unit 116. The magnetic gripper 100 adheres to a relatively large workpiece W at one suction point. Therefore, when a sudden load F indicated by the arrow is applied to an end of the workpiece W, the magnetic gripper 100 peels off the workpiece W at a load F that is weaker than the maximum adhesive force of the gripper unit 116.

[0036] 5, the magnetic gripper 14 of this embodiment attracts a relatively large workpiece W with a first gripper unit 16 and a second gripper unit 16A that are spaced apart in the axial direction. Therefore, even if a sudden load F as indicated by the arrow is applied to an end of the workpiece W, the load F can be distributed and supported at the two attraction points, preventing the workpiece W from falling off.

[0037] Furthermore, the magnetic gripper 14 can drive the two gripper units 16, 16A with a single drive mechanism 22, which prevents the device configuration from becoming complicated.

[0038] Second Embodiment As shown in Fig. 7, a magnetic gripper 14A of this embodiment differs from the magnetic gripper 14 shown in Fig. 1 in the position of the drive mechanism 22. The other configuration of the magnetic gripper 14A is similar to that of the magnetic gripper 14 shown in Fig. 1. In the configuration of the magnetic gripper 14A, parts that are similar to those corresponding to the magnetic gripper 14 are given the same reference numerals, and descriptions thereof will be omitted.

[0039] In the magnetic gripper 14A of this embodiment, the drive mechanism 22 is connected to the rotary shaft 20 at a portion between the first gripper unit 16 and the second gripper unit 16A. The drive motor 38 of the drive mechanism 22 is attached to the upper surface of the intermediate housing 24. The transmission mechanism 40 has a belt 40c that passes through an opening 24a provided in the upper surface of the intermediate housing 24, and is connected to the drive shaft 38a of the drive motor 38 and the rotary shaft 20 through the opening 24a in the intermediate housing 24.

[0040] Third Embodiment As shown in Figures 8A and 8B, this embodiment relates to a first gripper unit 16B according to a modified example. The first gripper unit 16B of this embodiment differs from the first gripper unit 16 described with reference to Figures 1 to 3A in the first yoke 26B and the air gap portion 36B. The other configuration of the first gripper unit 16B is similar to that of the first gripper unit 16 shown in Figures 2 and 3A. In the first gripper unit 16B, portions similar to those of the first gripper unit 16 are designated by the same reference numerals, and descriptions thereof will be omitted.

[0041] The first yoke 26B is separated into a first portion 42 located closer to the first side portion 26e in the width direction and a second portion 44 located closer to the second side portion 26f. The first portion 42 and the second portion 44 are integrally formed from a magnetic material with high magnetic permeability. A plate member 46 is attached between the first portion 42 and the second portion 44 as the air gap portion 36B. The plate member 46 is made of a non-magnetic material. The plate member 46 is located at the center in the width direction and extends in the axial direction. In this embodiment, the air gap portion 36B is formed by the plate member 46. The plate member 46 is liquid-tightly joined to the first portion 42 and the second portion 44 and liquid-tightly seals the outer periphery of the accommodation chamber 34.

[0042] 8A , when the N and S poles of the first gripper unit 16B face the first portion 42 and the second portion 44, the air gap portion 36B prevents short-circuiting of magnetic flux inside the first yoke 26B. As a result, the magnetic flux of the first magnet 28 is directed toward the pair of pole pieces 30, generating an attractive force for the workpiece W. Also, as shown in FIG. 8B , when the N and S poles of the first magnet 28 face the plate member 46, the magnetic flux is short-circuited inside the first portion 42 and the second portion 44. In this case, magnetic flux is not emitted from the pair of pole pieces 30, and therefore the first gripper unit 16B does not generate an attractive force.

[0043] As described above, the same effects as those of the magnetic gripper 14 in Fig. 1 can be obtained. The structure of the first gripper unit 16B can also be applied to the second gripper unit 16A shown in Fig. 3B.

[0044] Fourth Embodiment As shown in FIG. 9 , a magnetic gripper 14C of this embodiment includes a third gripper unit 16C in addition to the first gripper unit 16 and the second gripper unit 16A. The third gripper unit 16C includes a third yoke 26C, a third magnet 28C, a pair of pole pieces 30, and an air gap portion 36. The third yoke 26C is configured similarly to the first yoke 26 of the first gripper unit 16 (see FIG. 3A ), and the third magnet 28C is configured similarly to the first magnet 28 of the first gripper unit 16 (see FIG. 3A ). The pair of pole pieces 30 are also similar to the pole piece 30 of the first gripper unit 16 (see FIG. 3A ). The third magnet 28C is arranged so that its rotation axis is coaxial with the rotation axes of the first magnet 28 and the second magnet 28A, and is magnetized in the same direction of rotation.

[0045] The magnetic gripper 14C has a rotating shaft 20. The rotating shaft 20 extends linearly along the rotation axis of the first magnet 28, the second magnet 28A, and the third magnet 28C, connecting them to one another. A drive mechanism 22 is connected to an end 20a of the rotating shaft 20. The rotating shaft 20 rotates the first magnet 28, the second magnet 28A, and the third magnet 28C integrally by the rotational force of the drive mechanism 22. The drive mechanism 22 of the magnetic gripper 14C is the same as the drive mechanism 22 described with reference to FIG. 1.

[0046] The magnetic gripper 14C of this embodiment attracts the workpiece W at three attraction points. Therefore, the magnetic gripper 14C can stably transport a larger workpiece W. Note that, although the above description has been given of an example in which the magnetic gripper 14C has three gripper units, this embodiment is not limited to this. The magnetic gripper 14C may have four or more gripper units.

[0047] The following additional notes are further disclosed regarding the above embodiment.

[0048] (Supplementary Note 1) The magnetic gripper (14, 14A, 14C) of the present disclosure comprises a first gripper unit (16, 16B) having a first magnet (28) magnetized in a diameter direction perpendicular to a rotation axis parallel to an attraction surface, a second gripper unit (16A) having a second magnet (28A) magnetized in a diameter direction perpendicular to the rotation axis, and a rotating shaft (20) connecting the first magnet and the second magnet and rotating the first magnet (28) and the second magnet (28A) around the rotation axis, and the first gripper unit and the second gripper unit are arranged at a distance such that the attraction force due to the magnetic force of the first magnet and the attraction force due to the magnetic force of the second magnet do not affect each other.

[0049] The above-described magnetic gripper can stably transport large workpieces with a simple device configuration while suppressing an increase in the weight of the gripper unit.

[0050] (Supplementary Note 2) In the magnetic gripper described in Supplementary Note 1, the first gripper unit has a first yoke (26, 26B) that houses the first magnet and transmits the magnetic force of the first magnet to the workpiece (W), the second gripper unit has a second yoke (26A) that houses the second magnet and transmits the magnetic force of the second magnet to the workpiece, the first yoke and the second yoke are spaced apart from each other in the direction of the rotation axis, and it is not necessary to form a magnetic circuit between the first magnet and the second magnet. This magnetic gripper can transport workpieces efficiently and stably with a small number of gripper units.

[0051] (Supplementary Note 3) In the magnetic gripper according to Supplementary Note 1 or 2, the first magnet and the second magnet may be arranged such that the position of the N pole of the first magnet and the position of the N pole of the second magnet are the same in the rotation direction. This magnetic gripper can switch between attracting and releasing the multiple gripper units by rotating a single rotating shaft.

[0052] (Supplementary Note 4) In the magnetic gripper described in any one of Supplementary Notes 1 to 3, each of the first magnet and the second magnet may be composed of a plurality of disk-shaped magnetic pieces (28a) arranged at intervals in the direction of the rotation axis. This magnetic gripper can generate an attractive force by dispersing the magnetic force over a wide range while reducing the weight of the magnet.

[0053] (Supplementary Note 5) In the magnetic gripper described in Supplementary Note 3 or 4, the first magnet and the second magnet may have the same configuration. By making the first magnet and the second magnet the same component, the magnetic gripper can reduce device costs.

[0054] (Supplementary Note 6) The magnetic gripper according to any one of Supplementary Notes 1 to 5 may include an intermediate housing (24) that connects the first gripper unit and the second gripper unit and accommodates the rotating shaft. This magnetic gripper can protect the rotating shaft from dust and water.

[0055] (Supplementary Note 7) In the magnetic gripper described in Supplementary Note 2, the first yoke and the second yoke may have a magnet accommodating chamber (34, 34A) that rotatably accommodates the first magnet or the second magnet, and an air gap portion (36, 36A) that is perpendicular to the rotation axis and is located at the center in the width direction parallel to the attraction surface and that prevents magnetic flux from flowing in the width direction. This magnetic gripper can generate and release an attraction force by the rotation of the first magnet and the second magnet.

[0056] (Supplementary Note 8) In the magnetic gripper described in Supplementary Note 7, the air gap portion may have a groove formed by cutting out the first yoke or the second yoke. This magnetic gripper has excellent waterproof properties because the air gap portion does not have any openings on the top and bottom surfaces.

[0057] (Supplementary Note 9) In the magnetic gripper according to any one of Supplementary Notes 2, 7, and 8, the first gripper unit and the second gripper unit may have pole pieces (30) replaceably attached to the first yoke and the second yoke, respectively. By making the pole pieces, which are prone to wear, replaceable, this magnetic gripper can reduce maintenance costs.

[0058] (Supplementary Note 10) The magnetic gripper according to any one of Supplements 1 to 9 may further include a third gripper unit (16C) having a third magnet (28C) magnetized in a diameter direction perpendicular to the rotation axis, the third magnet being connected to the first magnet and the second magnet via the rotating shaft, and the third gripper unit being disposed in a position not affected by the magnetic attraction force of the first magnet and the second magnet. This magnetic gripper can stably transport larger-sized workpieces at three attraction points.

[0059] (Supplementary Note 11) The magnetic gripper according to any one of Supplementary Notes 1 to 10 may further include a drive mechanism (22) that rotates the rotating shaft, the drive mechanism being connected to one end (20 a) of the rotating shaft in the direction of extension of the rotation axis. This magnetic gripper can drive multiple gripper units with one drive mechanism.

[0060] (Supplementary Note 12) The magnetic gripper according to any one of Supplementary Notes 1 to 10, further comprising a drive mechanism (22) that rotates the rotating shaft, the drive mechanism being connected to the rotating shaft between the first gripper unit and the second gripper unit. Since the drive mechanism is not disposed at an end of the rotating shaft, the magnetic gripper can be made smaller in size in the axial direction.

[0061] (Supplementary Note 13) An industrial robot (10) according to the present disclosure includes the magnetic gripper according to any one of Supplementary Notes 1 to 12, and a robot arm (12) that holds and drives the magnetic gripper. This industrial robot can stably transport large workpieces.

[0062] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0063] DESCRIPTION OF SYMBOLS 10... Industrial robot 12... Robot arm 14, 14A, 14C... Magnetic gripper 16, 16A, 16B, 16C... Gripper unit 20... Rotating shaft 22... Drive mechanism 24... Intermediate housing 26, 26A, 26B, 26C... Yoke 28, 28A, 28C... Magnet 34, 34A... Storage chamber 36, 36A, 36B... Air gap portion

Claims

1. A magnetic gripper (14, 14A, 14C) comprising: a first gripper unit (16, 16B) having a first magnet (28) magnetized in a diameter direction perpendicular to a rotation axis parallel to an attraction surface; a second gripper unit (16A) having a second magnet (28A) magnetized in a diameter direction perpendicular to the rotation axis; and a rotating shaft (20) connecting the first magnet (28) and the second magnet (28A) and rotating the first magnet (28) and the second magnet (28A) about the rotation axis, wherein the first gripper unit (16, 16B) and the second gripper unit (16A) are arranged at a distance such that the attraction forces due to the magnetic force of the first magnet (28) and the attraction forces due to the magnetic force of the second magnet (28A) do not affect each other.

2. A magnetic gripper (14, 14A, 14C) according to claim 1, wherein the first gripper unit (16, 16B) has a first yoke (26, 26B) that houses the first magnet (28) and transmits the magnetic force of the first magnet (28) to the workpiece (W), the second gripper unit (16A) has a second yoke (26A) that houses the second magnet (28A) and transmits the magnetic force of the second magnet (28A) to the workpiece (W), and the first yoke (26, 26B) and the second yoke (26A) are spaced apart from each other in the direction of the rotation axis, and no magnetic circuit is formed between the first magnet (28) and the second magnet (28A).

3. A magnetic gripper (14, 14A, 14C) according to claim 1, wherein the first magnet (28) and the second magnet (28A) have the N pole position of the first magnet (28) and the N pole position of the second magnet (28A) identical in the direction of rotation.

4. A magnetic gripper (14, 14A, 14C) according to claim 3, wherein each of the first magnet (28) and the second magnet (28A) is composed of a plurality of disk-shaped magnetic pieces (28a) arranged at intervals in the direction of the rotation axis.

5. A magnetic gripper (14, 14A, 14C) according to claim 3, wherein the first magnet (28) and the second magnet (28A) have the same configuration.

6. A magnetic gripper (14, 14A, 14C) according to claim 1, comprising an intermediate housing (24) that connects the first gripper unit (16, 16B) and the second gripper unit (16A) and accommodates the rotating shaft (20).

7. A magnetic gripper (14, 14A, 14C) according to claim 2, wherein the first yoke (26, 26B) and the second yoke (26A) have a magnet accommodating chamber (34, 34A) that rotatably accommodates the first magnet (28) or the second magnet (28A), and an air gap portion (36, 36A) that is perpendicular to the rotation axis and is positioned at the center in the width direction parallel to the attraction surface, and that prevents magnetic flux from flowing in the width direction.

8. A magnetic gripper (14, 14A, 14C) according to claim 7, wherein the air gap portion (36, 36A) has a groove cut out of the first yoke (26) or the second yoke (26A).

9. A magnetic gripper (14, 14A, 14C) according to claim 2, wherein the first gripper unit (16, 16B) and the second gripper unit (16A) have pole pieces (30) interchangeably attached to the first yoke (26, 26B) and the second yoke (26A), respectively.

10. A magnetic gripper (14C) according to any one of claims 1 to 9, further comprising a third gripper unit (16C) having a third magnet (28C) magnetized in a diametric direction perpendicular to the rotation axis, the third magnet (28C) being connected to the first magnet (28) and the second magnet (28A) via the rotating shaft (20), and the third gripper unit (16C) being positioned so as not to be affected by the attractive force of the magnetic forces of the first magnet (28) and the second magnet (28A).

11. A magnetic gripper (14, 14C) according to any one of claims 1 to 9, comprising a drive mechanism (22) that rotates the rotating shaft (20), the drive mechanism (22) being connected to one end (20a) of the rotating shaft (20) in the direction of extension of the rotation axis.

12. A magnetic gripper (14A) according to any one of claims 1 to 9, comprising a drive mechanism (22) for rotating the rotating shaft (20), the drive mechanism (22) being connected to the rotating shaft (20) between the first gripper unit (16) and the second gripper unit (16A).

13. An industrial robot (10) comprising: a magnetic gripper (14, 14A, 14C) according to any one of claims 1 to 9; and a robot arm (12) that holds and drives the magnetic gripper (14, 14A, 14C).

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