Permanent electromagnetic holder and conveying device

Abstract

A permanent electromagnetic holder 1 is provided with: a first magnet 3 that has a relatively small coercive force; a ring-shaped second magnet 4 that is a rare-earth magnet having a relatively large coercive force; and a coil 5 for magnetizing the first magnet through energization thereof. The first magnet 3 is configured such that the magnetic pole surfaces of different magnetic poles are oriented in the thrust direction of an axial center α, the second magnet 4 is configured such that the magnetic pole surfaces of different magnetic poles are oriented in the thrust direction of an axial center α, and the second magnet 4 is disposed outside the first magnet in the radial direction of the axial center α. The first magnet 3, the second magnet 4, and the coil 5 are arranged so as to overlap in the radial direction of the axial center α, and an operation of switching an adsorption ON / OFF state is carried out by switching the magnetizing direction of the first magnet 3 through energization of the coil 5 when the adsorption ON / OFF state is switched.

Description

[Technical Field]

[0001] The present invention relates to a technology for a permanent electromagnetic holder and a transport device equipped with the permanent electromagnetic holder. [Background technology]

[0002] Conventionally, technology relating to a permanent electromagnetic holder equipped with a permanent magnet and a coil has been publicly known (see Patent Document 1). The permanent electromagnetic holder is configured to be able to attract an object to be attracted by the magnetic force of the permanent magnet, and is configured so that attraction of the object to be attracted is turned off when current is applied to the coil.

[0003] Furthermore, technology relating to a permanent electromagnetic suction device that includes a first permanent magnet, a second permanent magnet, and a coil, and that switches the magnetization direction of the first permanent magnet by switching the current direction and passing current through the coil, thereby switching the suction ON state and suction OFF state of the object to be suctioned, is publicly known (see Patent Document 2). The permanent electromagnetic type attracting device has a high attracting force, and can reduce power consumption because it does not require the coil to be continuously energized in the attracting-off state. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-102682 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-75020 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the permanent electromagnetic holder, the permanent magnet and the electromagnet are arranged side by side in the height direction (the direction perpendicular to the attraction surface), which causes a problem that the permanent electromagnetic holder is large in size in the height direction. In addition, in the permanent electromagnetic type attraction device, the first permanent magnet and the second permanent magnet are arranged side by side in the height direction (the direction perpendicular to the attraction surface). Therefore, although the permanent electromagnetic type attraction device has a high attraction force and can reduce power consumption, there is a problem that it is large in the height direction.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and its object is to provide a permanent electromagnetic holder that has a high suction force, reduces power consumption, and can be configured to be relatively thin. [Means for solving the problem]

[0007] The problem to be solved by the present invention is as described above, and the means for solving this problem will now be described.

[0008] That is, in claim 1, there is provided a permanent electromagnetic holder having an attraction surface for an object to be attracted, configured to be able to attract the object to be attracted in an attraction ON state, and configured to be able to release the attracted object to be attracted in an attraction OFF state, the permanent electromagnetic holder comprising a first magnet which is a magnet with a relatively small coercive force, a second magnet which is a rare earth magnet with a relatively large coercive force and configured in a ring shape, and a coil which magnetizes the first magnet when energized, and the first magnet has magnetic pole faces of different magnetic poles which are perpendicular to the attraction surface and which are oriented in a thrust direction of an axis passing through the center of the attraction surface. The second magnet is configured so that the magnetic pole faces of the different magnetic poles face in the thrust direction of the axis and is arranged outside the first magnet in the radial direction of the axis, the coil is arranged between the first magnet and the second magnet, and the first magnet, the second magnet, and the coil are arranged so as to overlap in the radial direction of the axis, and the operation of switching between the attraction ON / OFF states is performed by passing electricity through the coil to switch the magnetization direction of the first magnet when switching between the attraction ON / OFF states.

[0009] In claim 2, a front yoke is provided which is arranged close to the first magnet, the second magnet, and the coil on the attracting surface side in the thrust direction of the axis of the first magnet, the second magnet, and the coil, and a part of the front yoke is configured to protrude on the first magnet side of the coil, on the opposite side of the attracting surface side in the thrust direction of the axis, beyond the attracting surface side end of the coil.

[0010] In claim 3, a back yoke is provided, the bottom of which is located on the side opposite the adsorbing surface side in the thrust direction of the axis, and the opening of which is located on the adsorbing surface side in the thrust direction of the axis, the first magnet, the second magnet, and the coil are located inside the back yoke, the front yoke is arranged to cover the opening of the back yoke, and a portion of the back yoke is configured to protrude toward the adsorbing surface side in the thrust direction of the axis, on the first magnet side of the coil, further than the end of the coil opposite the adsorbing surface side.

[0011] In claim 4, a conveying device is provided with the permanent electromagnetic holder. [Effects of the Invention]

[0012] The present invention has the following effects. That is, according to the present invention, it is possible to provide a high chucking force, reduce power consumption, and have a thin structure. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a cross-sectional view showing a permanent electromagnetic holder according to an embodiment of the present invention. [Figure 2] (a) is a schematic plan view showing the first magnet, the second magnet, and the coil when the permanent electromagnetic holder is in the attraction-ON state, and (b) is a schematic cross-sectional view showing the permanent electromagnetic holder in the attraction-ON state. [Figure 3](a) is a schematic plan view showing the first magnet, the second magnet, and the coil when the permanent electromagnetic holder is in the attraction OFF state, and (b) is a schematic cross-sectional view showing the permanent electromagnetic holder in the attraction OFF state. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] This is also a schematic cross-sectional view showing the permanent electromagnetic holder in the suction ON state. [Figure 8] This is also a schematic cross-sectional view showing the permanent electromagnetic holder in the suction ON state. [Figure 9] This is also a schematic cross-sectional view showing the permanent electromagnetic holder in the suction ON state. [Figure 10] This is also a schematic cross-sectional view showing the permanent electromagnetic holder in the suction OFF state. [Figure 11] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, the permanent electromagnetic holder 1 will be described with reference to Figures 1 to 6. In the following description, the broken lines in the figures represent loops of magnetic lines of force.

[0015] The permanent electromagnetic holder 1 is configured to be able to attract an iron product or the like (attachment target 2) using magnetic force. The permanent electromagnetic holder 1 is configured to be able to switch between an ON / OFF suction state. The permanent electromagnetic holder 1 is configured to be able to attract the attraction target 2 when in the attraction ON state, and to be able to release the attracted attraction target 2 when in the OFF state. The permanent electromagnetic holder 1 can be used in a transport device that transports or carries iron products, etc., or a holding device that holds iron products in a state of being adsorbed to a wall surface, ceiling surface, etc. Specific examples of applications in which the permanent electromagnetic holder 1 is used include industrial robots and crane devices that grip and transport workpieces by magnetic force, aircraft such as helicopters and drones that suspend and transport steel frames, etc. by magnetic force, and wall-climbing robots that move while adsorbed to a wall surface by magnetic force. As shown in Figures 1 to 3, the permanent electromagnetic holder 1 is configured in a substantially cylindrical shape and has an attraction surface 1a for an object 2 to be attracted at one end in the thrust direction of the axis α. The axis α is perpendicular to the attraction surface 1a and passes through the center of the attraction surface 1a. The thrust direction of the axis α indicates the direction in which the axis α extends (the height direction of the permanent electromagnetic holder 1), and the radial direction of the axis α indicates the direction perpendicular to the direction of the axis α. The permanent electromagnetic holder 1 includes a first magnet 3, a second magnet 4, a coil 5, a front yoke 6, a back yoke 7, and a spacer 8. In the following description, for convenience, the direction in which the attracting surface 1a of the attracting target 2 in the permanent electromagnetic holder 1 faces downward, but the direction of the permanent electromagnetic holder 1 is not limited to this.

[0016] The first magnet 3 is a magnet with a relatively small coercive force (for example, an alnico magnet or an iron-chromium-cobalt magnet) and is configured in a cylindrical shape. The first magnet 3 is configured so that the magnetic pole faces of different magnetic poles (south pole and north pole) each face in the thrust direction of the axis α. The first magnet 3 is configured so that the magnetic pole faces of different magnetic poles are each arranged so as to be perpendicular to the thrust direction of the axis α.

[0017] The second magnet 4 is a rare earth magnet (e.g., a neodymium magnet) with a relatively large coercive force, and is configured in a cylindrical (ring) shape. The height of the second magnet 4 is configured to be approximately the same as the height of the first magnet 3. The second magnet 4 is configured so that the magnetic pole faces of different magnetic poles (south pole and north pole) each face in the thrust direction of the axis α. The second magnet 4 is configured so that the magnetic pole faces of different magnetic poles are each arranged so as to be perpendicular to the thrust direction of the axis α. The second magnet 4 is arranged radially outward of the first magnet 3 (outward of the first magnet 4 in the radial direction of the axis α). The second magnet 4 is arranged concentrically with the first magnet 3.

[0018] The first magnet 3 and the second magnet 4 are arranged at the same position in the thrust direction of the axis α. The first magnet 3 and the second magnet 4 are arranged so as to overlap in the radial direction of the axis α. The top surface position of the first magnet 3 and the top surface position of the second magnet 4 coincide in the thrust direction of the axis α, and the bottom surface position of the first magnet 3 and the bottom surface position of the second magnet 4 coincide in the thrust direction of the axis α.

[0019] Coil 5 is a solenoid coil, and when energized, generates a strong magnetic flux on the axis α side (first magnet 3 side), magnetizing first magnet 3. Coil 5 switches the magnetization direction of first magnet 3 by switching the energization direction and energizing it. The coil 5 is arranged in an annular shape between the first magnet 3 and the second magnet 4. The coil 5 is arranged radially outside the first magnet 3. The coil 5 is arranged radially inside the second magnet 4. The coil 5 is configured to be close to the first magnet 3 and the second magnet 4. The first magnet 3, the second magnet 4, and the coil 5 are arranged so as to overlap in the radial direction of the axis α.

[0020] The front yoke 6 is a yoke made of a material such as iron, and is configured in a substantially flat, disk-like shape. The front yoke 6 is disposed outside the first magnet 3, second magnet 4, and coil 5. The front yoke 6 is disposed below the first magnet 3, second magnet 4, and coil 5 (on the attracting surface 1a side in the thrust direction of the axis α), close to or in contact with them. The outer diameter of the front yoke 6 is configured to be substantially the same as the outer diameter of the second magnet 4.

[0021] The back yoke 7 is made of a material such as iron and has a generally cylindrical shape with a bottom and an opening. The bottom of the back yoke 7 is located at the top, and the opening is located at the bottom. The inner diameter of the back yoke 7 is larger than the outer diameter of the front yoke 6. The back yoke 7 is disposed outside the first magnet 3, the second magnet 4, and the coil 5. The first magnet 3, the second magnet 4, and the coil 5 are disposed inside the back yoke 7 (inside the back yoke 7). The back yoke 7 is configured to be close to or in contact with the first magnet 3, the second magnet 4, and the coil 5. The bottom of the back yoke 7 is located above the first magnet 3, the second magnet 4, and the coil 5, and the side walls of the back yoke 7 are located outside the first magnet 3, the second magnet 4, and the coil 5. The lower end (lower opening) of the back yoke 7 is located below the first magnet 3, the second magnet 4, and the coil 5. The lower end surface of the back yoke 7 is configured to be approximately flush with the lower surface of the front yoke 6.

[0022] The front yoke 6 is disposed so as to cover the opening of the back yoke 7. The lower surface of the front yoke 6 and the lower end surface of the back yoke 7 form an adsorption surface 1a. The spacer 8 is made of a non-magnetic material such as aluminum, and shields the magnetic flux of the first magnet 3 and the second magnet 4. The spacer 8 is fitted between the outer surfaces of the second magnet 4 and the front yoke 6 and the inner surface of the back yoke 7.

[0023] By switching the current flow direction and passing current through the coil 5, the magnetization direction of the first magnet 3 is switched, and the attraction state of the attraction target 2 is switched between an attraction ON state and an attraction OFF state. The operation of switching the attraction ON / OFF state is performed by momentarily passing electricity through the coil 5 when switching the attraction ON / OFF state (turning electricity ON and then immediately OFF) to switch the magnetization direction of the first magnet 3. In the permanent electromagnetic holder 1, for example, the magnetization direction (attraction ON / OFF state) of the first magnet 3 switches 0.01 to 0.2 seconds after electricity starts to be passed through the coil 5. In the attraction ON state, for example, if the magnetic pole of the second magnet 4 on the attraction surface 1a side is N, the magnetic pole of the first magnet 3 on the attraction surface 1a side is magnetized to N. In this way, the first magnet 3 is magnetized in the same direction as the magnetic pole of the second magnet 4, and the attraction ON state is established (see FIG. 2). In the attraction OFF state, for example, if the magnetic pole of the second magnet 4 on the attraction surface 1a side is a north pole, the magnetic pole of the first magnet 3 on the attraction surface 1a side is magnetized to a south pole. In this way, the magnetic flux of the first magnet 3 and the second magnet 4 is looped inside the front yoke 6 and the back yoke 7, preventing the magnetic flux of the first magnet 3 and the second magnet 4 from leaking outside the attraction surface 1a, thereby achieving the attraction OFF state (see FIG. 3).

[0024] In this way, the first magnet 3 is configured so that the magnetic pole faces of different magnetic poles each face in the thrust direction of the axis α, and the second magnet 4 is configured so that the magnetic pole faces of different magnetic poles each face in the thrust direction of the axis α, the first magnet 3, the second magnet 4 and the coil 5 are arranged so that they overlap in the radial direction of the axis α, and the attraction ON / OFF state is switched by passing electricity (instantaneously) through the coil 5 when switching the attraction ON / OFF state, thereby switching the magnetization direction of the first magnet 3. Therefore, the permanent electromagnetic holder 1 can be configured to have a higher attraction force than conventional permanent electromagnetic holders and to have a thinner profile while reducing power consumption. Furthermore, in conventional permanent electromagnetic holders, when the magnetic force of the permanent magnet is relatively strong, it is conceivable to configure the coil to be relatively large so as to cancel the magnetic force of the permanent magnet, but configuring the coil to be relatively large in this way results in an increase in size in the radial direction of the attracting surface (radial direction of the axis).However, the permanent electromagnetic holder 1 configured in this way can suppress an increase in size in the radial direction of the axis α while maintaining a high attracting force, compared to conventional permanent electromagnetic holders configured with a permanent magnet having a relatively strong magnetic force and a relatively large coil.

[0025] Furthermore, after switching the suction ON / OFF state, the permanent electromagnetic holder 1 maintains the switched suction ON / OFF state even when the coil 5 is not energized until the next switching operation of the suction ON / OFF state is performed. For this reason, the permanent electromagnetic holder 1 can prevent the magnetic body or the like from being attracted by mistake when, for example, the power goes out and the power supply is unintentionally cut off and the attraction is turned on, as in the case of a conventional permanent electromagnetic holder. Also, for example, it can prevent the magnetic body or the like from being attracted by mistake when the power supply is unintentionally cut off before the suspension position is set, as in the case of a conventional permanent electromagnetic holder.

[0026] As shown in Figure 1, the front yoke 6 has a groove 6a formed on its upper surface (the surface on which the first magnet 3, second magnet 4, or coil 5 is arranged in the thrust direction of the axis α), and is configured to have a step on the upper surface. The groove 6a of the front yoke 6 is a rectangular groove, has a circular ring shape in a plan view, and is formed concentrically with the first magnet 3 or the second magnet 4. The outer diameter of the groove 6a of the front yoke 6 is configured to be approximately the same as the inner diameter of the second magnet 4. The inner diameter of the groove 6a of the front yoke 6 is configured to be approximately the same as the outer diameter of the first magnet 3.

[0027] A portion (lower portion) of the coil 5 is disposed in the groove 6a of the front yoke 6. The coil 5 is disposed so that its lower end (the end on the attracting surface 1a side) is wedged into the upper portion of the front yoke 6. A portion of the front yoke 6 is configured to protrude upward (the side where the first magnet 3, second magnet 4, or coil 5 is disposed in the thrust direction of the axis α (the side opposite the attracting surface 1a side in the thrust direction of the axis α)) on the inside of the coil 5 (the first magnet 3 side) beyond the lower end of the coil 5 (the end on the attracting surface 1a side). A portion of the front yoke 6 is configured to protrude upward beyond the lower end of the coil 5 on the outside of the coil 5 (the second magnet 4 side).

[0028] In this way, the end of the coil 5 on the attracting surface 1a side is inserted into the upper part of the front yoke 6. The permanent electromagnetic holder 1 is configured so that a portion of the front yoke 6 protrudes from the first magnet 3 side of the coil 5 toward the opposite side of the attracting surface 1a in the thrust direction of the axis α beyond the end of the coil 5 on the attracting surface 1a side. This allows the permanent electromagnetic holder 1 to increase the magnetic flux toward the axis α side (first magnet 3 side), and magnetize the first magnet 3 with relatively little power consumption.

[0029] The back yoke 7 is configured such that a groove 7a is formed on the lower surface of the bottom (the surface on which the first magnet 3, second magnet 4, or coil 5 is arranged in the thrust direction of the axis α) and has a step on the lower surface. The groove 7a of the back yoke 7 is a rectangular groove, has a circular ring shape when viewed from the bottom, and is formed concentrically with the first magnet 3 or the second magnet 4. The outer diameter of the groove 7a of the back yoke 7 is configured to be approximately the same as the inner diameter of the second magnet 4. The inner diameter of the groove 7a of the back yoke 7 is configured to be approximately the same as the outer diameter of the first magnet 3.

[0030] A portion (upper portion) of the coil 5 is disposed in the groove 7a of the back yoke 7. The coil 5 is disposed so that its upper end (the end opposite the attracting surface 1a) fits into the bottom of the back yoke 7. A portion of the back yoke 7 is configured to protrude downward (in the thrust direction of the axis α, on the side where the first magnet 3, second magnet 4, or coil 5 is disposed (the attracting surface 1a side in the thrust direction of the axis α)) on the inside of the coil 5 (the first magnet 3 side) beyond the upper end of the coil 5 (the end opposite the attracting surface 1a side). A portion of the back yoke 7 is configured to protrude downward beyond the upper end of the coil 5 on the outside of the coil 5 (the second magnet 4 side).

[0031] In this way, the end of the coil 5 opposite the attracting surface 1a is positioned to bite into the bottom of the back yoke 7, and the back yoke 7 is configured so that a portion of the back yoke 7, on the first magnet 3 side of the coil 5, protrudes toward the attracting surface 1a in the thrust direction of the axis α beyond the end of the coil 5 opposite the attracting surface 1a. Therefore, in the permanent electromagnetic holder 1, the magnetic flux toward the axis α side (first magnet 3 side) can be increased, and the first magnet 3 can be magnetized with relatively little power.

[0032] The permanent electromagnetic holder 1 does not have to be configured in a cylindrical shape, but can also be configured in a polygonal shape (for example, a rectangular prism). Furthermore, the first magnet 3 does not have to be configured in a cylindrical shape, and the second magnet 4 does not have to be configured in a cylindrical shape. That is, the first magnet 3 can be configured in a polygonal prism shape (for example, a rectangular prism), and the second magnet 4 can be configured in a polygonal cylindrical shape (for example, a rectangular prism). The second magnet 4 may be configured in a ring shape by arranging a plurality of rare earth magnets each having a predetermined shape (for example, a sector shape). The grooves 6a of the front yoke 6 or the grooves 7a of the back yoke 7 may be formed as round or polygonal grooves.

[0033] 4, the permanent electromagnetic holder 1 can be configured such that the front yoke 6 does not have the groove 6a on its upper surface but has a flat upper surface, and the back yoke 7 does not have the groove 7a on its lower surface of its bottom but has a flat lower surface. By configuring it in this way, the permanent electromagnetic holder 1 can be manufactured relatively easily. Furthermore, the permanent electromagnetic holder 1 can also be configured so that the height of the second magnet 4 is different from the height of the first magnet 3. In this case, for example, as shown in FIG. 5, the length (height) of the axis α of the second magnet 4 in the thrust direction is configured to be shorter than the length (height) of the axis α of the first magnet 3 in the thrust direction. A recess is formed on the upper surface of the front yoke 6, and a recess is also formed on the lower surface of the bottom of the back yoke 7. The outer diameter of the recess in the front yoke 6 and the outer diameter of the recess in the back yoke are configured to be approximately the same as the inner diameter of the second magnet 4. The first magnet 3 and the coil 5 are arranged in the recess in the front yoke 6 and the recess in the back yoke. Furthermore, the permanent electromagnetic holder 1 can also be configured so that the outer diameter of the front yoke 6 is different from the outer diameter of the second magnet 4. In this case, for example, as shown in FIG. 6, the outer diameter of the front yoke 6 is configured to be shorter than the outer diameter of the second magnet 4.

[0034] Next, the permanent electromagnetic holder 1 shown in FIGS. 7 to 10 will be described. In describing the permanent electromagnetic holder 1 shown in Figures 7 to 10, the description of parts that are similar to the permanent electromagnetic holder 1 shown in Figures 1 to 6 will be omitted as appropriate, and the description will focus on parts that are different from the permanent electromagnetic holder 1 shown in Figures 1 to 6.

[0035] 7 to 10, the permanent electromagnetic holder 1 includes a first magnet portion 10 and a second magnet portion 20, and is configured such that the first magnet portion 10 and the second magnet portion 20 are aligned in the thrust direction of the axis α. The first magnet portion 10 is positioned closer to the attraction surface 1a than the second magnet portion 20 in the thrust direction of the axis α. The first magnet section 10 includes a first magnet 13, a second magnet 14, a first coil 15, a front yoke 16, a first back yoke 17, and a spacer 18.

[0036] The first magnet 13 is a magnet with a relatively small coercive force (for example, an alnico magnet or an iron-chromium-cobalt magnet) and is configured in a cylindrical shape. The first magnet 13 is configured so that the magnetic pole faces of different magnetic poles (south pole and north pole) each face in the thrust direction of the axis α. The first magnet 13 is configured so that the magnetic pole faces of different magnetic poles are each arranged so as to be perpendicular to the thrust direction of the axis α. The second magnet 14 is a rare earth magnet (e.g., a neodymium magnet) with a relatively large coercive force, and is configured in a cylindrical (ring) shape. The height of the second magnet 14 is configured to be approximately the same as the height of the first magnet 13. The second magnet 14 is configured so that the magnetic pole faces of different magnetic poles (south pole and north pole) each face in the thrust direction of the axis α. The second magnet 14 is configured so that the magnetic pole faces of different magnetic poles are each arranged so as to be perpendicular to the thrust direction of the axis α. The first magnet 13 and the second magnet 14 are disposed at the same position in the thrust direction of the axis α.

[0037] First coil 15 is a solenoid coil, and when energized, generates a strong magnetic flux on the axis α side (first magnet 13 side), magnetizing first magnet 13. Coil 15 switches the magnetization direction of first magnet 13 by switching the energization direction and energizing it. The first coil 15 is disposed between the first magnet 13 and the second magnet 14. The first coil 15 is disposed radially outward from the first magnet 13. The first coil 15 is disposed radially inward from the second magnet 14. The first coil 15 is configured to be close to the first magnet 13 and the second magnet 14. First magnet 13, second magnet 14, and first coil 15 are arranged so as to overlap in the radial direction of axis α.

[0038] The front yoke 16 is a yoke made of a material such as iron and is configured in a generally flat disk shape. The front yoke 16 is disposed below the first magnet 13, the second magnet 14, and the first coil 15, in close proximity to or in contact with them.

[0039] First back yoke 17 is a yoke made of a material such as iron, and is configured in a substantially cylindrical shape having a bottom and an opening. The bottom of first back yoke 17 is located at the top, and the opening is located at the bottom. The inner diameter of first back yoke 17 is configured to be larger than the outer diameter of front yoke 16. The first back yoke 17 is disposed outside the first magnet 13, the second magnet 14, and the first coil 15. The first magnet 13, the second magnet 14, and the first coil 15 are disposed inside the first back yoke 17. The first back yoke 17 is configured to be close to or in contact with the first magnet 13, the second magnet 14, and the first coil 15. The bottom of the first back yoke 17 is located above the first magnet 13, the second magnet 14, and the first coil 15, and the side walls of the first back yoke 17 are located outside the first magnet 13, the second magnet 14, and the first coil 15. The lower end (lower opening) of the first back yoke 17 is located below the first magnet 13, the second magnet 14, and the first coil 15. The lower end surface of the first back yoke 17 is configured to be approximately flush with the lower surface of the front yoke 16.

[0040] The front yoke 16 is disposed so as to cover the opening of the first back yoke 17 . The spacer 18 is made of a non-magnetic material such as aluminum, and shields the magnetic flux of the first magnet 13, the second magnet 14, the third magnet 23, and the fourth magnet 24. The spacer 18 is fitted between the outer surfaces of the second magnet 14 and the front yoke 16 and the inner surface of the first back yoke 17.

[0041] The second magnet section 20 includes a third magnet 23, a fourth magnet 24, a second coil 25, a second back yoke 27, and a spacer 28.

[0042] The third magnet 23 is a magnet with a relatively small coercive force (for example, an alnico magnet or an iron-chromium-cobalt magnet) and is configured in a cylindrical shape. The outer diameter of the third magnet 23 is larger than the inner diameter of the second magnet 14 but smaller than the outer diameter of the second magnet 14. The third magnet 23 is configured so that its magnetic pole faces face the thrust direction of the axis α. The third magnet 23 is configured so that the magnetic pole faces (south pole and north pole) of different magnetic poles are arranged so that they are perpendicular to the thrust direction of the axis α. The third magnet 23 is disposed above the first back yoke 17 so as to be close to or in contact with the upper surface of the first back yoke 17. The third magnet 23 is disposed on an axis concentric with the axes of the first magnet 13 and the second magnet 14.

[0043] The fourth magnet 24 is a rare earth magnet (e.g., a neodymium magnet) with a relatively large coercive force, and is configured in a cylindrical (ring) shape. The height of the fourth magnet 24 is configured to be approximately the same as the height of the third magnet 23. The outer diameter of the fourth magnet 24 is configured to be larger than the outer diameter of the second magnet 14. The fourth magnet 24 is configured so that the magnetic pole faces of different magnetic poles (south pole and north pole) each face in the thrust direction of the axis α. The fourth magnet 24 is configured so that the magnetic pole faces of different magnetic poles are each arranged so as to be perpendicular to the thrust direction of the axis α. The fourth magnet 24 is disposed above the first back yoke 17 so as to be close to or in contact with the upper surface of the first back yoke 17. The fourth magnet 24 is disposed radially outside the third magnet 23 (outside the third magnet 23 in the radial direction of the axis α). The fourth magnet 24 is disposed concentrically with the first magnet 13, the second magnet 14, and the third magnet 23.

[0044] The third magnet 23 and the fourth magnet 24 are disposed at the same position in the thrust direction of the axis α. The third magnet 23 and the fourth magnet 24 are disposed so as to overlap in the radial direction of the axis α. The upper surface position of the third magnet 23 and the upper surface position of the fourth magnet 24 coincide in the thrust direction of the axis α, and the lower surface position of the third magnet 23 and the lower surface position of the fourth magnet 24 coincide in the thrust direction of the axis α.

[0045] Second coil 25 is a solenoid coil, and when energized, generates a strong magnetic flux on the axis α side (third magnet 23 side), magnetizing third magnet 23. When energized while switching the energization direction, second coil 25 switches the magnetization direction of third magnet 23. The second coil 25 is disposed between the third magnet 23 and the fourth magnet 24. The second coil 25 is disposed radially outward from the third magnet 23. The second coil 25 is disposed radially inward from the fourth magnet 24. The second coil 25 is configured to be close to the third magnet 23 and the fourth magnet 24. The third magnet 23, the fourth magnet 24, and the second coil 25 are arranged so as to overlap in the radial direction of the axis α.

[0046] The second back yoke 27 is a yoke made of a material such as iron, and is configured in a substantially cylindrical shape having a bottom and an opening. The bottom of the second back yoke 27 is located at the top, and the opening is located at the bottom. The inner diameter of the second back yoke 27 is configured to be larger than the outer diameter of the first back yoke 17. The second back yoke 27 is disposed outside the first magnet portion 10 (first magnet 13, second magnet 14, first coil 15), third magnet 23, fourth magnet 24, and second coil 25. The first magnet portion 10 (first magnet 13, second magnet 14, first coil 15), third magnet 23, fourth magnet 24, and second coil 25 are disposed inside the second back yoke 27. The second back yoke 27 is configured to be close to or in contact with the third magnet 23, fourth magnet 24, and second coil 25. The bottom of the second back yoke 27 is located above the third magnet 23, fourth magnet 24, and second coil 25, and the sidewalls of the second back yoke 27 are located outside the first magnet portion 10 (first magnet 13, second magnet 14, first coil 15), third magnet 23, fourth magnet 24, and second coil 25. The lower end portion (lower opening) of the second back yoke 27 is located below the third magnet 23, the fourth magnet 24, and the second coil 25. The lower end surface of the second back yoke 27 is configured to be substantially flush with the lower surface of the front yoke 16 and the lower end surface of the first back yoke 17.

[0047] The spacer 28 is made of a non-magnetic material such as aluminum, and shields the magnetic flux of the first magnet 13, the second magnet 14, the third magnet 23, and the fourth magnet 24. The spacer 28 is fitted between the outer surface of the fourth magnet 24 and the first back yoke 17 and the inner surface of the second back yoke 27. The lower surface of the front yoke 16, the lower end surface of the first back yoke 17, and the lower end surface of the second back yoke 27 are configured as an adsorption surface 1a.

[0048] By switching the current flow direction and passing current through the first coil 15 and / or the second coil 25, the magnetization direction of the first magnet 13 and / or the third magnet 23 is switched, and the attraction target 2 is switched between an attraction ON state and an attraction OFF state. The operation of switching the attraction ON / OFF state is performed by instantaneously passing current through the first coil 15 and / or the second coil 25 when switching the attraction ON / OFF state (turning current ON to the first coil 15 and / or the second coil 25 and then immediately turning current OFF to the first coil 15 and / or the second coil 25), thereby switching the magnetization direction of the first magnet 13 and / or the magnetization direction of the third magnet 23. For example, in the permanent electromagnetic holder 1, the magnetization direction of the first magnet 13 and / or the magnetization direction of the third magnet 23 (attraction ON / OFF state) switches 0.01 to 0.2 seconds after current begins to be passed through the first coil 15 and / or the second coil 25.

[0049] For example, in the attraction-ON state, if the magnetic pole of the second magnet 14 on the attraction surface 1a side is the north pole and the magnetic pole of the fourth magnet 24 on the attraction surface 1a side is the south pole, then by passing current only through the first coil 15, the magnetic pole of the first magnet 13 on the attraction surface 1a side is magnetized to the north pole. In this way, the first magnet 13 is magnetized in the same direction as the magnetic pole of the second magnet 14, and the attraction-ON state is established (see FIG. 7). Also, for example, in the attraction-ON state, if the magnetic pole of the second magnet 14 on the attraction surface 1a side is a north pole and the magnetic pole of the fourth magnet 24 on the attraction surface 1a side is a south pole, by passing current only through the second coil 25, the magnetic pole of the third magnet 23 on the attraction surface 1a side is magnetized to a south pole. In this way, the third magnet 23 is magnetized in the same direction as the magnetic pole of the fourth magnet 24, and the attraction-ON state is established (see FIG. 8). At this time, a stronger attraction force for attracting the attraction target object 2 is generated compared to when the attraction-ON state is established by passing current only through the first coil 15. Furthermore, for example, in the attraction-ON state, if the magnetic pole of the second magnet 14 on the attracting surface 1a side is a north pole and the magnetic pole of the fourth magnet 24 on the attracting surface 1a side is a south pole, by passing current through the first coil 15 and the second coil 25, the magnetic pole of the first magnet 13 on the attracting surface 1a side is magnetized to a north pole and the magnetic pole of the third magnet 23 on the attracting surface 1a side is magnetized to a south pole. In this way, the first magnet 13 is magnetized in the same direction as the magnetic pole of the second magnet 14, and the third magnet 23 is magnetized in the same direction as the magnetic pole of the fourth magnet 24, resulting in the attraction-ON state (see FIG. 9 ). At this time, a stronger attraction force for attracting the attraction target object 2 is generated compared to when the attraction-ON state is achieved by passing current only through the first coil 15 or only through the second coil 25.

[0050] In the attraction-off state, for example, if the magnetic pole of the second magnet 14 on the attracting surface 1a side is a north pole and the magnetic pole of the fourth magnet 24 on the attracting surface 1a side is a south pole, the magnetic pole of the first magnet 13 on the attracting surface 1a side is magnetized to a south pole, and the magnetic pole of the third magnet 23 on the attracting surface 1a side is magnetized to a north pole. In this way, the magnetic flux of the first magnet 13, second magnet 14, third magnet 23, and fourth magnet 24 is looped inside the front yoke 16, first back yoke 17, and second back yoke 27, preventing the magnetic flux of the first magnet 13, second magnet 14, third magnet 23, and fourth magnet 24 from leaking outside the attracting surface 1a, thereby achieving the attraction-off state (see FIG. 10 ).

[0051] In this way, the first magnet portion 10 is disposed closer to the attracting surface 1a than the second magnet portion 20 in the thrust direction of the axis α, the first magnet 13 is configured so that the magnetic pole faces of different magnetic poles face the thrust direction of the axis α, the second magnet 14 is configured so that the magnetic pole faces of different magnetic poles face the thrust direction of the axis α, the first magnet 13, the second magnet 14, and the first coil 15 are disposed so as to overlap in the radial direction of the axis α, and the third magnet 23 is configured so that the magnetic pole faces of different magnetic poles face the thrust direction of the axis α. The third magnet 23, the fourth magnet 24, and the second coil 25 are arranged so that their magnetic pole faces face the thrust direction of the axis α, and the third magnet 23, the fourth magnet 24, and the second coil 25 are arranged so that they overlap in the radial direction of the axis α, and the attraction ON / OFF state is switched by passing electricity (instantaneously) through the first coil 15 and / or the second coil 25 when switching the attraction ON / OFF state, thereby switching the magnetization direction of the first magnet 13 and the magnetization direction of the third magnet 23. Therefore, the permanent electromagnetic holder 1 has a higher attraction force and reduces power consumption compared to conventional permanent electromagnetic holders, and can be configured to be relatively thin in a configuration in which the first magnet portion 10 and the second magnet portion 20 are arranged side by side in the thrust direction of the axis α.

[0052] When switching between the suction ON / OFF state, the mode of energizing the coils (first coil 15 and / or second coil 25) can be selected from among energizing the first coil 15, energizing the second coil 25, or energizing the first coil 15 and the second coil 25. The mode of energizing the coils is selected, for example, by a company employee operating an operation switch or the like. For example, when it is desired to make the attraction force for attracting the attraction target 2 relatively weak, the selection is made to energize only the first coil 15 when switching between the attraction ON / OFF states. Furthermore, for example, if it is desired to strengthen the suction force for suctioning the object to be suctioned 2 compared to when current is applied only to the first coil 15, when switching the suction ON / OFF state, the selection is made to apply current only to the second coil 25. Furthermore, for example, if it is desired to strengthen the suction force for suctioning the object to be suctioned 2 compared to when current is passed through only the first coil 15 or only the second coil 25, then when switching the suction ON / OFF state, the first coil 15 and the second coil 25 are selected to be energized.

[0053] In this way, when switching the suction ON / OFF state, it is possible to select the mode in which current is passed through the coils, from among passing current through the first coil 15, passing current through the second coil 25, or passing current through both the first coil 15 and the second coil 25. Therefore, it is possible to set the suction force for adsorbing the object to be adsorbed 2 to be changed depending on the specifications of the object to be adsorbed 2 and the use of the permanent electromagnetic holder 1, etc. The permanent electromagnetic holder 1 may be configured such that only the first coil 15 and the second coil 25 are energized when switching between the chucking ON / OFF state.

[0054] The front yoke 16 is configured such that a groove (not shown) is formed on the upper surface thereof, and the upper surface has a step. A portion (lower portion) of the first coil 15 is disposed in the groove of the front yoke 16. The first coil 15 is disposed so that its lower end (the end on the attracting surface 1a side) is wedged into the upper portion of the front yoke 16. A portion of the front yoke 16 is configured to protrude upward from the lower end (the end on the attracting surface 1a side) of the first coil 15 on the inside of the first coil 15 (the first magnet 13 side). A portion of the front yoke 16 is configured to protrude upward from the lower end of the first coil 15 on the outside of the first coil 15 (the second magnet 14 side).

[0055] In this way, the end of the first coil 15 on the attracting surface 1a side is disposed so as to bite into the upper part of the front yoke 16, and a part of the front yoke 16 is configured to protrude on the first magnet 13 side of the first coil 15 toward the opposite side of the attracting surface 1a side in the thrust direction of the axis α beyond the end of the first coil 15 on the attracting surface 1a side. Therefore, in the permanent electromagnetic holder 1, the magnetic flux toward the axis α side (first magnet 13 side) can be increased, and the first magnet 13 can be magnetized with relatively little power consumption.

[0056] The first back yoke 17 is configured such that a groove (not shown) is formed in the lower surface of the bottom portion, and the lower surface has a step. A portion (upper portion) of the first coil 15 is disposed in the groove of the first back yoke 17. The first coil 15 is disposed so that its upper end (the end opposite the attracting surface 1a) is embedded in the bottom of the first back yoke 17. A portion of the first back yoke 17 is configured to protrude downward (in the thrust direction of the axis α, toward the side where the first magnet 13, the second magnet 14, or the first coil 15 is disposed (the attracting surface 1a side in the thrust direction of the axis α)) on the inside of the first coil 15 (the first magnet 13 side) beyond the upper end (the end opposite the attracting surface 1a) of the first coil 15. A portion of the first back yoke 17 is configured to protrude downward beyond the upper end of the first coil 15 on the outside of the first coil 15 (the second magnet 14 side).

[0057] In this way, the end of the first coil 15 opposite the attracting surface 1a side is disposed so as to bite into the bottom of the first back yoke 17, and the first back yoke 17 is configured so that a portion of the first back yoke 17, on the first magnet 13 side of the first coil 15, protrudes toward the attracting surface 1a side in the thrust direction of the axis α beyond the end of the first coil 15 opposite the attracting surface 1a side. Therefore, in the permanent electromagnetic holder 1, the magnetic flux toward the axis α side (first magnet 13 side) can be increased, and the first magnet 13 can be magnetized with relatively little power consumption.

[0058] The second back yoke 27 may also be configured such that, like the front yoke 16, a groove (not shown) is formed in the upper surface of the bottom, thereby providing a step on the upper surface. A portion (lower portion) of the second coil 25 is disposed in the groove of the second back yoke 27. The second coil 25 is disposed so that its lower end portion (end portion on the attracting surface 1a side) is wedged into the upper portion of the second back yoke 27. A portion of the second back yoke 27 is configured to protrude upward from the lower end portion (end portion on the attracting surface 1a side) of the second coil 25 on the inside of the second coil 25 (third magnet 23 side). A portion of the second back yoke 27 is configured to protrude upward from the lower end portion of the second coil 25 on the outside of the second coil 25 (fourth magnet 24 side).

[0059] In this way, the end of the second coil 25 on the attracting surface 1a side is disposed so as to bite into the upper part of the second back yoke 27, and a part of the second back yoke 27 is configured to protrude on the third magnet 23 side of the second coil 25 toward the opposite side of the attracting surface 1a side in the thrust direction of the axis α beyond the end of the second coil 25 on the attracting surface 1a side. Therefore, in the permanent electromagnetic holder 1, the magnetic flux toward the axis α side (first magnet 13 side) can be increased, and the first magnet 13 can be magnetized with relatively little power consumption.

[0060] Similar to the first back yoke 17, the second back yoke 27 may be configured such that a groove (not shown) is formed in the lower surface of the bottom portion, thereby providing a step on the lower surface. A portion (upper portion) of the second coil 25 is disposed in the groove of the second back yoke 27. The second coil 25 is disposed so that its upper end (the end opposite the attracting surface 1a) is wedged into the bottom of the second back yoke 27. A portion of the second back yoke 27 is configured to protrude downward (toward the side where the third magnet 23, the fourth magnet 24, or the second coil 25 is disposed in the thrust direction of the axis α (the attracting surface 1a side in the thrust direction of the axis α)) from the upper end (the end opposite the attracting surface 1a) of the second coil 25 inside the second coil 25 (the third magnet 23 side). A portion of the second back yoke 27 is configured to protrude downward from the upper end of the second coil 25 outside the second coil 25 (the fourth magnet 24 side).

[0061] In this way, the second coil 25 is arranged so that the end opposite to the attracting surface 1a side is wedged into the bottom of the second back yoke 27, and the second back yoke 27 is configured so that a portion of the second back yoke 27, on the third magnet 23 side of the second coil 25, protrudes toward the attracting surface 1a side in the thrust direction of the axis α beyond the end of the second coil 25 opposite to the attracting surface 1a side. Therefore, in the permanent electromagnetic holder 1, it is possible to increase the magnetic flux toward the axis α side (third magnet 23 side), and magnetize the third magnet 23 with relatively little power.

[0062] The permanent electromagnetic holder 1 may also be configured such that, in addition to the first magnet portion 10 and the second magnet portion 20, three or more magnet portions are arranged in a line in the thrust direction of the axis α. The second magnet 14 or the fourth magnet 24 may be configured in a ring shape by arranging a plurality of rare earth magnets having a predetermined shape (for example, a sector shape). The grooves of the front yoke 16, the second back yoke 17, or the second back yoke 27 may be formed as round or polygonal grooves.

[0063] 11, the permanent electromagnetic holder 1 can also be configured such that the coil 5 is disposed above the second magnet 4 (on the opposite side to the attracting surface 1a in the thrust direction of the axis α) and is disposed so as to bite into the back yoke 7. In this case, the first magnet 3 and the second magnet 4 are disposed so as to overlap in the radial direction of the axis α, and the coil 5 is disposed radially outside the first magnet 3 and above the second magnet 4, and the coil 5 and the second magnet 4 are disposed so as to overlap in the thrust direction of the axis α. By configuring in this way, the permanent electromagnetic holder 1 can increase the magnetic flux toward the axis α side (first magnet 3 side), and the first magnet 3 can be magnetized with relatively little power consumption. [Industrial Applicability]

[0064] The present invention is utilized in a permanent electromagnetic holder configured to be able to attract an object to be attracted using magnetic force, and a conveyance device equipped with the permanent electromagnetic holder. [Explanation of symbols]

[0065] 1 Permanent electromagnetic holder 1a Adsorption surface 2. Object to be adsorbed 3 First magnet 4 Second magnet 5 coils 6 Front Yoke 6a Groove 7 Back Yoke 7a Groove 8 spacers 10 First magnet section 13 First magnet 14 Second magnet 15 First coil 16 Front Yoke 17 First Back Yoke 18 spacer 20 Second magnet part 23 Third magnet 24 Fourth magnet 25 Second coil 27 Second back yoke 28 spacer α axis center

Claims

1. A permanent electromagnetic holder having an attraction surface for an object to be attracted, configured to be able to attract the object to be attracted in an attraction-on state, and configured to be able to detach the attracted object to be attracted in an attraction-off state, a first magnet having a relatively small coercive force; a second magnet that is a rare earth magnet with a relatively large coercive force and is configured in a ring shape; a coil that magnetizes the first magnet when energized; a back yoke having a bottom portion disposed on a side opposite to an adsorption surface side in a thrust direction of an axis, and an opening portion disposed on the adsorption surface side in the thrust direction of the axis; a front yoke disposed to cover the opening of the back yoke, the first magnet, the second magnet, and the coil are disposed inside the back yoke, the first magnet is configured such that magnetic pole faces of different magnetic poles face in a thrust direction of the axis that is perpendicular to the attracting surface and passes through a center of the attracting surface, the second magnet is configured so that magnetic pole faces of different magnetic poles face in a thrust direction of the axis, and is disposed outside the first magnet in a radial direction of the axis, the coil is wound around a portion of the back yoke and a portion of the front yoke between the first magnet and the second magnet and is disposed so as to bite into the back yoke and the front yoke, the first magnet, the second magnet, and the coil are arranged to overlap in the radial direction of the axis, The switching operation of the attraction ON / OFF state is performed by momentarily energizing the coil to switch the magnetization direction of the first magnet when switching the attraction ON / OFF state. Permanent electromagnetic holder.

2. A permanent electromagnetic holder having an attraction surface for an object to be attracted, configured to be able to attract the object to be attracted in an attraction-on state, and configured to be able to detach the attracted object to be attracted in an attraction-off state, a first magnet having a relatively small coercive force; a second magnet that is a rare earth magnet with a relatively large coercive force and is configured in a ring shape; a coil that magnetizes the first magnet when energized; the first magnet is configured such that magnetic pole faces of different magnetic poles face in a thrust direction of an axis that is perpendicular to the attracting surface and passes through a center of the attracting surface, the second magnet is configured so that magnetic pole faces of different magnetic poles face in a thrust direction of the axis, and is disposed outside the first magnet in a radial direction of the axis, the coil and the second magnet are arranged to overlap in a thrust direction of the axis, the first magnet and the second magnet are arranged to overlap in the radial direction of the axis, The switching operation of the attraction ON / OFF state is performed by momentarily energizing the coil to switch the magnetization direction of the first magnet when switching the attraction ON / OFF state. Permanent electromagnetic holder.

3. The first magnet is configured such that the length of the shaft center in the thrust direction is shorter than the length of the shaft center in the radial direction, The second magnet is configured to be annular, and the length of the shaft center in the thrust direction is configured to be shorter than the length of the shaft center in the radial direction. The permanent electromagnetic holder according to claim 1 or 2.

4. a back yoke having a bottom portion disposed on a side opposite to an adsorption surface side in a thrust direction of the axis, and an opening portion disposed on the adsorption surface side in the thrust direction of the axis, the first magnet, the second magnet, and the coil are disposed inside the back yoke, The coil is wound around a portion of the back yoke on the inner side of the back yoke and is disposed so as to bite into the back yoke. The permanent electromagnetic holder according to claim 2 .

5. A transport device comprising the permanent electromagnetic holder according to any one of claims 1 to 4.

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