JP2007208024A - Magnetic circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic circuit including a permanent magnet and an excitation coil capable of energizing the excitation coil so as to change over a magnetic action surface between an excitation state and a non-excitation state with less power consumption, without breaking a permanent magnet even when a ferrite magnet or a rare earth magnet is used as the permanent magnet, which is excellent in magnetic characteristic but friable in terms of material. <P>SOLUTION: The permanent magnet or a permanent magnet assembly is rotatably arranged in a columnar hole enclosed by first and second yokes. When instant energization is performed to the excitation coil so as to rotate the permanent magnet or the permanent magnet assembly, magnetic connection is changed over. Accordingly, the collision of the magnetic polar surface of the permanent magnet or the permanent magnet assembly with the connection surface of the first and second yokes is eliminated so as to prevent the permanent magnet from being broken. Thus, change-over is performed between the excitation state to allow a magnetic flux from the permanent magnet to pass the magnetic action surface and the non-excitation state to allow the magnetic flux not to pass. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a magnetic circuit including a permanent magnet and an excitation coil, and by energizing the excitation coil, the magnetic working surface can be switched between an excitation state in which a magnetic field is generated and a non-excitation state in which no magnetic field is generated. The present invention relates to a magnetic circuit.

  As a first example of a conventional apparatus having a magnetic circuit capable of switching a magnetic action surface between an excited state and a non-excited state, there is a so-called electromagnet device including an exciting coil and an iron core. An electromagnet device is a device that maintains an excited state by continuing energization of an exciting coil and maintains a non-excited state by not energizing. The electromagnet device is simple in structure and easy to operate remotely. However, the electromagnet device is energized in order to maintain the excited state, and therefore requires a large amount of electric energy, and is not a device that is friendly to the global environment. Further, if energization of the exciting coil is continued for a long time, the temperature of the exciting coil is increased, the electric resistance is increased, and the current is decreased, so that the magnetic ability is lowered. If a cooling device is attached to prevent this, the structure of the device becomes complicated, the cost increases, and more energy is required.

  As a second example of the conventional device, there is a so-called permanent magnet device including a permanent magnet and a yoke. The permanent magnet device does not require electrical energy to maintain the excited state, but switching between the excited state and the non-excited state is generally performed by rotating or moving the permanent magnet or yoke by human power. The use of the device is limited to the extent that it is difficult to remotely control the device and can exert human power.

  Further, as a third example of the conventional device, there is a device (lifting magnet) shown in Japanese Utility Model Application Publication No. 2-35745 having both an exciting coil and a permanent magnet. This is because a pair of yokes arranged vertically opposite to each other are fitted with electromagnetic coils (the same as the exciting coil), and permanent magnet steel having a lateral direction between the upper and lower yokes is attached to the electromagnetic coils. It is arranged so as to be movable in the vertical direction by electromagnetic force, and a mild steel member having a height dimension larger than the vertical thickness of the permanent magnet steel is fixed to both ends of the permanent magnet steel, whereby the permanent magnet steel is Only the mild steel member is in contact with the upper and lower yokes without contact with the yoke, and the permanent magnet steel is moved between the upper and lower yokes by the attraction and repulsion action with the permanent magnet steel by the excitation reversal operation of the electromagnetic coil. This is characterized in that the suspended material is adsorbed and released at the lower end of the lower yoke.

In the third example of the conventional apparatus, since the magnetic material is attracted and held by the magnetic force of the permanent magnet (that is, the excited state is maintained), it is not necessary to constantly energize the electromagnetic coil, and switching of the adsorption release (that is, Only at the time of switching between the excited state and the non-excited state), it is only necessary to energize the electromagnetic coil and move the permanent magnet. Since this switching is performed instantaneously, instantaneous energization is sufficient. Therefore, the third example is a device that consumes less power than the first example, and remote control is easier than the second example.
Utility Model Application Notice 2-35-2745

  In the first example of the conventional device, the power consumption is too large, and in the second example of the conventional device, remote operation is difficult. In the third example of the conventional device, the permanent magnet is sandwiched between the fixed mild steel members, and the permanent magnets move with the mild steel member even though the permanent magnets do not directly contact the upper and lower yokes when switching between adsorption and release. Then, since it collides with the upper and lower yokes, the impact is also applied to the permanent magnet, and the permanent magnet is easily damaged. In particular, permanent magnets that are excellent in magnetic properties but brittle in material, such as ferrite magnets and rare earth magnets, are very easily damaged in this third example, and can hardly be used.

  An object of the present invention is a magnetic circuit that can be switched between an excited state and a non-excited state, and it is only necessary to energize an electromagnetic coil only at the time of switching, and it is a magnetic circuit that consumes less power and can be easily operated remotely. In particular, it is to provide a magnetic circuit that is excellent in magnetic properties, such as a ferrite magnet or a rare earth magnet, but does not cause damage to the permanent magnet even when a permanent magnet that is brittle in material is used.

  The magnetic circuit of the present invention includes a first yoke having a first magnetic action surface, a second yoke having a second magnetic action surface and magnetically insulated from the first yoke, And a permanent magnet or permanent magnet assembly rotatably disposed in a cylindrical hole surrounded by the second yoke, and an excitation coil, and energizing the excitation coil to provide a permanent magnet or permanent magnet assembly. And rotating the magnetic connection between the magnetic pole surface of the permanent magnet or the permanent magnet assembly and the connection surfaces of the first yoke and the second yoke exposed on the inner surface of the cylindrical hole, The second magnetic action surface can be switched between an excited state where a magnetic field is generated and a non-excited state where a magnetic field is not generated.

  In the magnetic circuit of the present invention, the first and / or second yoke can be made into an electromagnet by energizing the exciting coil to generate a magnetomotive force, and exposed to the inner surface of the cylindrical hole. The connecting surface can be N-pole or S-pole. Then, the N pole and the S pole of the magnetic pole surface of the permanent magnet or the permanent magnet assembly are moved away from the N pole and the S pole of the connection surface receiving the repulsive force, respectively, and the S pole and the N pole of the connection surface receiving the attractive force, respectively. Therefore, the magnetic connection between the magnetic pole surface and the connection surface can be switched. At this time, if the magnetomotive force of the exciting coil is sufficient, the permanent magnet or the permanent magnet assembly is rotated instantaneously, and therefore the energization to the exciting coil may be instantaneous. After the magnetic connection between the magnetic pole surface and the connection surface is switched, the excited state and the non-excited state can be stably held by the magnetic force of the permanent magnet even if the exciting coil is not energized. Various structures and operations of the magnetic circuit of the present invention will be described in detail in Examples.

  The magnetic circuit of the present invention can be switched between an excited state and a non-excited state by instantaneous energization of the exciting coil, and is a magnetic circuit with low power consumption. Remote operation is also easy. Furthermore, since the magnetic connection is switched by the rotation of the permanent magnet or the permanent magnet assembly, there is no collision between the magnetic pole surface and the connection surface, and it has excellent magnetic properties, especially ferrite magnets and rare earth magnets. Even if a brittle permanent magnet is used, the permanent magnet is not damaged.

  1 to 4 show a magnetic circuit 10 as a first embodiment of the present invention. This magnetic circuit 10 is a device usually called a lifting magnet or the like. (Alternatively, it may be called a magnet base or a magnet holder.) The outer shape is substantially a rectangular parallelepiped shape, and has an attracting surface (that is, a magnetic acting surface) for attracting and holding the magnetic material on the lower surface. However, in the drawing, a lifting eye bolt or a screw hole or the like disposed on the top of a normal lifting magnet is omitted. 1 and 3 are sectional views in the vertical direction passing through the center of the permanent magnet, and FIG. 1 is a section taken along the line 1-1 in FIG. FIG. 2 is a horizontal sectional view passing through the center of the permanent magnet, and is a section 2-2 in FIG. FIG. 4 is a front view.

  First, the structure of the magnetic circuit 10 will be described. Referring to FIG. 1, the first yoke 11 has a first magnetic action surface 12, and the second yoke 13 has a second magnetic action surface 14. The first yoke 11 and the second yoke 13 are magnetically insulated by separators 15 and 16 made of a nonmagnetic material. A cylindrical hole 17 extending in the horizontal direction is surrounded by the first yoke 11, the second yoke 13, and the separators 15 and 16, and the first and second yokes exposed in the holes are exposed. The surface portions are the connection surface A and the connection surface E, respectively.

  The permanent magnet 20 has a cylindrical side surface portion so as to match the inner surface of the cylindrical hole 17, and is disposed in the cylindrical hole 17 so as to be rotatable about its central axis as a rotation axis. The permanent magnet 20 is magnetized so that the cylindrical side surface portions are magnetic pole surfaces 20a (N pole in FIG. 1) and 20b (S pole in FIG. 1). Therefore, the magnetic pole surfaces 20 a and 20 b can be magnetically connected to the connection surface A and the connection surface E on the inner surface of the cylindrical hole 17. Side surfaces other than the magnetic pole surfaces 20a and 20b are cut out in a planar shape.

  The exciting coil 23 is disposed so as to surround a part of the first yoke 11 and is connected to a power source (not shown). Although the exciting coil 23 is embedded in the first yoke 11, the first yoke 11 is disposed so as to pass through the inside of the exciting coil 23 but not through the outside. An upper surface plate 24 made of a nonmagnetic material is disposed on the upper surface of the magnetic circuit 10 to protect the exciting coil 23, and even if any magnetic material contacts the upper surface, the first yoke 11 and the second yoke 13 are protected. Magnetic connection is prevented from occurring. A lower surface plate 25 made of a nonmagnetic material is disposed on the lower surface to protect the exciting coil 23 and to magnetically connect the first yoke 11 and the second yoke 13 even if any magnetic material contacts the lower surface. To prevent it from happening.

  Referring to FIG. 2, rotating shaft portions 28 and 29 are disposed at both ends of the permanent magnet 20 in the rotating shaft direction. The rotary shaft portions 28 and 29 have grip portions 28 a and 29 a for gripping the permanent magnet 20, respectively. The rotary shaft portions 28 and 29 are supported by bearing portions 30 and 31, respectively. The bearing portions 30 and 31 are disposed on a front plate 26 and a back plate 27 made of a nonmagnetic material, respectively. The front plate 26 and the back plate 27 protect the exciting coil 23, and the magnetic connection between the first yoke 11 and the second yoke 13 does not occur even if any magnetic material contacts the front and back surfaces. I have to.

  Referring to FIGS. 2 and 4, a handle 32 is attached to a portion protruding outward of the rotary shaft portion 28. Further, stoppers 33 and 34 for restricting the rotation of the handle 32 (that is, the rotation of the permanent magnet 20) are arranged on the front plate 26. The stoppers 33 and 34 can adjust the protrusion length of the front-end | tip parts 33b and 34b by rotating the screws 33a and 34a, respectively. However, when the rotary shaft portions 28 and 29 and the handle 32 are not arranged, the cylindrical shape is formed from the lower surface of the first yoke 11 and the right side surface of the second yoke 13 as a stopper for limiting the rotation of the permanent magnet 20. It is possible to arrange a screw projecting on the inner surface of the hole 17 so as to contact a portion of the side surface of the permanent magnet 20 that is cut out in a flat shape, but it is not preferable.

  Next, the operation and effect of the magnetic circuit 10 will be described. Referring to FIG. 1, the N pole surface 20 a of the permanent magnet is magnetically connected to the connection surface A, and the S pole surface 20 b is magnetically connected to the connection surface E. Therefore, the magnetic flux of the permanent magnet 20 passes from the N pole surface 20a in the direction of the arrow 35, and the first yoke 11, the first magnetic action surface 12, the magnetic body 40, the second magnetic action surface 14, and the second magnetic action surface. It returns to the south pole face 20b of the permanent magnet through the yoke 13. That is, FIG. 1 shows an excited state in which a magnetic field is generated on the first and second magnetic action surfaces and the magnetic body 40 can be attracted and held.

  In order to switch the excitation state of FIG. 1 to the non-excitation state, the excitation coil 23 is energized so that the connection surface A becomes the N pole and the first magnetic action surface 12 becomes the S pole. The S pole of the first magnetic action surface 12 passes through the magnetic body 40 and the connection surface E of the second yoke 13 becomes the S pole. Then, the N pole surface 20a of the permanent magnet receives a magnetic repulsive force from the N pole of the connection surface A, and the S pole surface 20b of the permanent magnet receives a magnetic repulsive force from the S pole of the connection surface E. Magnet 20 begins to rotate. At this time, in order to ensure that the permanent magnet 20 rotates clockwise in FIG. 1, the permanent magnet 20 rotates clockwise slightly in advance rather than the N pole surface 20a and S pole surface 20b of the permanent magnet being in the horizontal position. It is preferable that the tip 33b (see FIG. 4) of the stopper 33 protrude a little longer so that it is in the position. As a result, the permanent magnet rotates clockwise, and the handle 32 comes into contact with the tip 34b of the stopper 34 when the permanent magnet rotates approximately 90 degrees. This state is the non-excited state shown in FIG.

  Referring to FIG. 3, the N pole surface 20a and the S pole surface 20b of the permanent magnet are connected to both the connection surface A and the connection surface E substantially equally with the separators 15 and 16 interposed therebetween. That is, the left half of the N pole face 20a and the S pole face 20b of the permanent magnet is magnetically short-circuited by the first yoke 11, and the magnetic flux passes in the direction of the arrow 36. Further, the right half of the N pole face 20 a and the S face pole 20 b of the permanent magnet is magnetically short-circuited by the second yoke 13, and the magnetic flux passes in the direction of the arrow 37. Therefore, FIG. 3 shows a non-excitation state in which there is no magnetic flux passing through the first and second magnetic action surfaces, and no magnetic field is generated on the first and second magnetic action surfaces (that is, no attracting force is generated). ing. In the non-excited state, the magnetic body 40 that has been attracted and held is released.

  In order to switch the non-excitation state of FIG. 3 to the excitation state of FIG. 1, the excitation coil 23 is energized in the opposite direction so that the connection surface A is the S pole and the first magnetic action surface 12 is the N pole. To. Then, the N pole surface 20a of the permanent magnet receives a magnetic attractive force from the S pole of the connection surface A, the permanent magnet 20 rotates approximately 90 degrees counterclockwise, and the handle 32 stops against the tip 33b of the stopper 33. . The entire N pole surface 20a of the permanent magnet is magnetically connected to the connection surface A, and the entire S pole surface 20b is magnetically connected to the connection surface E. This state is the excitation state shown in FIG.

  In the magnetic circuit 10, switching between the excited state and the non-excited state only requires switching the energizing direction to the exciting coil 23, so that remote operation is easy. In addition, if the magnetomotive force of the exciting coil 23 is sufficient, the permanent magnet 20 rotates instantaneously, and even after the magnetic connection between the magnetic pole surface and the connecting surface is switched, there is no need to energize the exciting coil 23. Since the excitation state and the non-excitation state can be stably maintained by the magnetic force of the permanent magnet 20, the excitation coil 23 can be energized instantaneously. Therefore, the magnetic circuit 10 is a magnetic circuit with low power consumption.

  Further, in the magnetic circuit 10, the permanent magnet 20 only rotates around the central axis and does not collide with the connection surface A and the connection surface E, so that the permanent magnet 20 is not damaged. In particular, even if a permanent magnet that is excellent in magnetic properties such as a ferrite magnet or a rare earth magnet but is brittle in material is used, the permanent magnet is not damaged. More preferably, an impact absorbing member such as a rubber or a spring can be disposed at the tip portions 33b and 34b of the stoppers 33 and 34 to which the handle 32 hits.

  Even after the magnetic circuit 10 is switched to the excitation state shown in FIG. 1, the energization to the excitation coil 23 can be continued. Thereby, the magnetic field generated on the first and second magnetic action surfaces can be strengthened, and the magnetic body 40 can be attracted and held more strongly. Furthermore, the magnetic field generated on the first and second magnetic action surfaces can be weakened by weakly energizing the exciting coil 23 in the opposite direction. In addition, a lock mechanism can be attached to the handle 32 so that an unexpected force is applied to the handle 32 from the outside and the permanent magnet 20 is not rotated.

  Even when the magnetic circuit 10 is switched to the non-excited state shown in FIG. 3, the attraction force remains due to the magnetization caused by the material of the magnetic body 40 that is the object to be attracted, making it difficult to release the magnetic body 40. There is. In such a case, the tip 34b of the stopper 34 shown in FIG. 4 is projected slightly shorter, and the rotation of the handle 32 (that is, the rotation of the permanent magnet 20) is rotated slightly more clockwise than the vertical position. You should stop it. As a result, the area of the S pole face 20b of the permanent magnet connected to the connection surface A is larger than the area of the N pole face 20a, and the area of the N pole face 20a of the permanent magnet connected to the connection face E is S pole face 20b. Larger than the area. Therefore, a weak south pole is generated on the first magnetic action surface, and a weak north pole is generated on the second magnetic action surface. Acts, the magnetization caused by the material of the magnetic body 40 is canceled out, and the release becomes easy.

  5 to 7 show a magnetic circuit 50 as a second embodiment of the present invention. This magnetic circuit 50 is also a device usually called a lifting magnet or the like. The outer shape is a substantially rectangular parallelepiped shape, and has an attracting surface (that is, a magnetic acting surface) for attracting and holding the magnetic material on the lower surface. However, in the drawing, a lifting eye bolt or a screw hole or the like disposed on the top of a normal lifting magnet is omitted. 5 and 7 are vertical sectional views passing through the center of the permanent magnet, and FIG. 5 is a sectional view taken along the line 5-5 in FIG. FIG. 6 is a horizontal cross-sectional view passing through the center of the permanent magnet, which is a 6-6 cross section of FIG.

  First, the structure of the magnetic circuit 50 will be described. Referring to FIG. 5, the first yoke 51 has a side plate portion 52, an upper connection portion 53, and a lower connection portion 54, and has a first magnetic action surface 55 on the lower surface of the side plate portion 52. The second yoke 56 has a second magnetic action surface 57 on the lower surface. The upper connecting portion 53, the lower connecting portion 54, and the second yoke 56 of the first yoke are magnetically insulated by separators 61, 62, 63 made of a nonmagnetic material. A cylindrical hole 64 extending in the horizontal direction is surrounded by the upper connecting portion 53, the lower connecting portion 54, the second yoke 56, and the separators 61, 62, 63 of the first yoke. The surface portions of the upper connection portion 53 and the lower connection portion 54 exposed in the cylindrical hole 64 are the connection surface B1 and the connection surface B2, respectively, and the second yoke exposed in the cylindrical hole 64. Is the connection surface E.

  The exciting coil 65 is disposed so as to surround the boundary between the side plate portion 52 and the upper connecting portion 53 of the first yoke 51, and is connected to a power source (not shown). The exciting coil 65 is embedded in the first yoke. When the magnetic circuit 50 is manufactured, the side plate portion 52 of the first yoke 51 is assembled at a position indicated by a two-dot chain line, and the exciting coil is assembled. After arranging 65, the side plate part 52 can be attached with a screw or the like. A top plate 66 made of a non-magnetic material is disposed on the top surface of the magnetic circuit 50 to protect the exciting coil 65, and even if any magnetic material contacts the top surface, the first yoke 51 and the second yoke 56 Magnetic connection is prevented from occurring.

  The permanent magnet assembly 69 is rotatably disposed in the cylindrical hole 64 with its central axis as the rotation axis. The permanent magnet assembly 69 has a permanent magnet 70 in the center, and magnetic pole members 71 and 72 made of a magnetic material are disposed on the left and right magnetic pole surfaces of the permanent magnet 70, respectively. The outer end surfaces of the magnetic pole members 71 and 72 are magnetic pole surfaces 71 a and 72 a having cylindrical side surface shapes so as to match the inner surface of the cylindrical hole 64. The permanent magnet assembly 69 includes covers 73 and 74 made of a nonmagnetic material, and protects the permanent magnet 70.

  Referring to FIG. 6, rotating shaft portions 75 and 76 made of a nonmagnetic material are disposed at both ends of the permanent magnet assembly 69 in the rotating shaft direction. The rotary shaft portions 75 and 76 have grip portions 75 a and 76 a for gripping the permanent magnet assembly 69, respectively. Both the grip portions 75a and 76a are coupled to the magnetic pole members 71 and 72 by screws or the like. The rotating shaft portions 75 and 76 are supported by bearing portions 77 and 78, respectively. The bearing portions 77 and 78 are disposed on a front plate 67 and a back plate 68 made of a nonmagnetic material, respectively. The front plate 67 and the back plate 68 protect the exciting coil 65, and the magnetic connection between the first yoke 51 and the second yoke 56 does not occur even if any magnetic material contacts the front and back surfaces. I have to. A handle 79 may be attached to a portion protruding outside the rotating shaft portion 75. However, the rotating shaft portions 75 and 76 and the handle 79 may not be arranged.

  Next, the operation and effect of the magnetic circuit 50 will be described. Referring to FIG. 5, one magnetic pole surface 71a (N pole in FIG. 5) of the permanent magnet assembly 69 is magnetically connected to the connecting surface B1, and the other magnetic pole surface 72a (S pole in FIG. 5) is magnetically connected to the connecting surface E. Connected to. Therefore, the magnetic flux of the permanent magnet assembly 69 passes from the N pole surface 71a in the direction of the arrow 81, and the first yoke 51, the first magnetic action surface 55, the magnetic body 85, the second magnetic action surface 57, 2 returns to the S pole surface 72a of the permanent magnet assembly 69 through the yoke 56. That is, FIG. 5 shows an excited state in which a magnetic field is generated on the first and second magnetic action surfaces and the magnetic body 85 can be attracted and held.

  In order to switch the excitation state of FIG. 5 to the non-excitation state, the excitation coil 65 is energized so that the connection surface B1 becomes the N pole, and the first magnetic action surface 55 and the connection surface B2 become the S pole. The S pole of the first magnetic acting surface 55 passes through the magnetic body 85 and turns the connection surface E of the second yoke 56 into the S pole. At this time, the N pole surface 71a of the permanent magnet assembly receives a magnetic repulsive force from the N pole of the connection surface B1, and receives a magnetic attractive force from the S pole of the nearby connection surface B2. The S pole surface 72a of the permanent magnet assembly receives a magnetic repulsive force from the S pole of the connection surface E, and receives a magnetic attractive force from the N pole of the nearby connection surface B1. Therefore, the permanent magnet assembly 69 rotates 90 degrees counterclockwise in FIG. 5, the N pole surface 71a is magnetically connected to the S pole of the connection surface B2, and the S pole surface 72a is the N pole of the connection surface B1. And stop magnetically connected. This state is the non-excited state shown in FIG. After the permanent magnet assembly 69 is rotated, the non-excited state is maintained even if the energization of the exciting coil 65 is stopped.

  Referring to FIG. 7, the N pole surface 71a of the permanent magnet assembly is magnetically connected to the connection surface B2, and the S pole surface 72a of the permanent magnet assembly is magnetically connected to the connection surface B1. Therefore, the permanent magnet assembly 69 is magnetically short-circuited by the first yoke 51, and the magnetic flux passes in the direction of the arrow 82. Accordingly, FIG. 7 shows a non-excitation state in which no magnetic field is generated on the first magnetic action surface 55 and the second magnetic action surface 57 (that is, no attracting force is generated). In the non-excited state, the magnetic body 85 that has been attracted and held is released.

  In order to switch the non-excitation state of FIG. 7 to the excitation state of FIG. 5, the exciting coil 65 is energized in the opposite direction to the above, the connection surface B1 is the S pole, and the first magnetic action surface 55 and the connection surface B2 are N. Try to be the pole. At this time, the N pole surface 71a of the permanent magnet assembly receives a magnetic repulsive force from the N pole of the connection surface B2, and receives a magnetic attractive force from the S pole of the nearby connection surface B1. Accordingly, the permanent magnet assembly 69 rotates 90 degrees clockwise in FIG. 7 and enters the excited state of FIG.

  In the magnetic circuit 50, switching between the excited state and the non-excited state only requires switching the energizing direction to the exciting coil 65, so that remote operation is easy. Further, if the magnetomotive force of the exciting coil 65 is sufficient, the permanent magnet assembly 69 is instantaneously rotated. After the magnetic connection between the magnetic pole surface and the connecting surface is switched, the exciting coil 65 is energized. Even if not, the excitation state and the non-excitation state can be stably maintained by the magnetic force of the permanent magnet, so that the excitation coil 65 may be energized instantaneously. Therefore, the magnetic circuit 50 is a magnetic circuit with low power consumption.

  Further, in the magnetic circuit 50, the permanent magnet assembly 69 only rotates around the central axis, and the permanent magnet assembly 69 does not collide with the connection surfaces B1, B2, and E. There is no damage. In particular, even if a permanent magnet that is excellent in magnetic properties such as a ferrite magnet or a rare earth magnet but is brittle in material is used, the permanent magnet 70 is not damaged.

  Even after the magnetic circuit 50 is switched to the excitation state shown in FIG. 5, the energization to the excitation coil 65 can be continued. Thereby, the magnetic field generated on the first and second magnetic action surfaces can be strengthened, and the magnetic body 85 can be attracted and held more strongly. Further, the magnetic field generated on the first and second magnetic action surfaces can be weakened by weakly energizing the exciting coil 65 in the opposite direction.

  Even when the magnetic circuit 50 is switched to the non-excited state shown in FIG. 7, the attractive force remains due to the magnetization caused by the material of the magnetic body 85 that is the object to be attracted, making it difficult to release the magnetic body 85. There is. In such a case, it is preferable that a slightly larger energization is instantaneously performed in the same direction as the energization of the excitation coil 65 when the non-excitation state is set. As a result, a stronger south pole is generated on the first magnetic action surface 55 and a stronger north pole is generated on the second magnetic action surface 57 and is attracted and held to the magnetic body 85. A stronger magnetic field opposite to the above acts, and the magnetization caused by the material of the magnetic body 85 is canceled out and the release becomes easy.

  When the handle 79 is attached, the rotation position of the permanent magnet assembly 69 can be confirmed by the rotation, and the permanent magnet assembly 69 can be manually rotated using the handle 79. In addition, a lock mechanism may be attached to the handle 79 so that an unexpected force is applied to the handle 79 from the outside and the permanent magnet assembly 69 is not rotated.

  Note that the structure shown in FIG. 5 of the magnetic circuit 50 is inverted upside down with the upper connecting portion 53 and the lower connecting portion 54 of the first yoke, the separator 61 and the exciting coil 65, with the section 6-6 in FIG. Even if the structure is changed, the same operation and effect as the magnetic circuit 50 are exhibited.

  FIG. 8 shows a magnetic circuit 100 as a third embodiment of the present invention. This magnetic circuit 100 is also a device normally called a lifting magnet or the like and is similar to the magnetic circuit 50 of the second embodiment. The outer shape of the magnetic circuit 100 is a substantially rectangular parallelepiped shape, and the magnetic material is attracted and held on the lower surface. It has an attracting surface (ie a magnetic working surface) FIG. 8 is a vertical sectional view passing through the center of the permanent magnet as in FIG. Note that a horizontal sectional view passing through the center of the permanent magnet is almost the same as that in FIG.

  First, the structure of the magnetic circuit 100 will be described. Referring to FIG. 8, the first yoke 101 has an upper plate portion 102, a side plate portion 103, an upper connection portion 104, a middle connection portion 105, and a lower connection portion 106, and the first yoke 101 is formed on the lower surface of the side plate portion 103. A magnetic working surface 107 is provided. The second yoke 108 has a second magnetic action surface 109 on the lower surface. The upper connecting portion 104, the middle connecting portion 105, the lower connecting portion 106, and the second yoke 108 of the first yoke are magnetically insulated by separators 111, 112, 113, 114 made of a nonmagnetic material, respectively. There is a cylindrical hole 116 surrounded by these and extending in the horizontal direction. The surface portions of the upper connection portion 104, the middle connection portion 105, and the lower connection portion 106 exposed in the cylindrical hole 116 are connection surfaces C1, C2, and C3, respectively, and are exposed in the cylindrical hole 116. The surface portion of the second yoke 108 is a connection surface E.

  The exciting coil 117 is disposed so as to surround the boundary between the upper plate portion 102 and the upper connecting portion 104 of the first yoke, and the exciting coil 118 is arranged at the boundary between the side plate portion 103 and the middle connecting portion 105 of the first yoke. The two exciting coils are connected to a power source (not shown). Both excitation coils 117 and 118 are embedded in the first yoke, but when the magnetic circuit 100 shown in FIG. 8 is manufactured, the upper plate portion 102 and the side plate portion 103 of the first yoke 101 are divided into two. The upper plate portion 102 and the side plate portion 103 can be attached with screws or the like after being assembled in the form of being separated at the position of the dotted line and arranging the exciting coils 117 and 118. In addition, a separator 115 is disposed for magnetic insulation between the upper plate portion 102 of the first yoke 101 and the second yoke 108.

  The permanent magnet assembly 119 is rotatably disposed in the cylindrical hole 116 with its central axis as the rotation axis. The permanent magnet assembly 119 is the same as the permanent magnet assembly 69 in the magnetic circuit 50 of the second embodiment. That is, magnetic pole members 121 and 122 made of a magnetic material are disposed on the left and right magnetic pole surfaces of the permanent magnet 120, respectively. The outer end surfaces of the magnetic pole members 121 and 122 are magnetic pole surfaces 121a and 122a having a cylindrical side surface shape so as to match the inner surface of the cylindrical hole 116. The permanent magnet assembly 119 includes covers 123 and 124 made of a nonmagnetic material, and protects the permanent magnet 120.

  Although not shown in the drawing, a rotating shaft portion made of a nonmagnetic material is disposed at both ends of the permanent magnet assembly 119 in the rotating shaft direction. Hereinafter, the structure of the rotating shaft and the like is the same as the structure of FIG. 6 described in the second embodiment, so refer to the description of FIG.

  Next, the operation and effect of the magnetic circuit 100 will be described. Referring to FIG. 8, one magnetic pole surface 121a (N pole in FIG. 8) of the permanent magnet assembly 119 is magnetically connected to the connecting surface C2, and the other magnetic pole surface 122a (S pole in FIG. 8) is magnetically connected to the connecting surface E. Connected to. Accordingly, the magnetic flux of the permanent magnet assembly 119 flows from the N pole surface 121a to the middle connection portion 105, the side plate portion 103, the first magnetic action surface 107, the magnetic body 135, the second magnetic action surface 109, and the first yoke. It returns to the S pole surface 122a of the permanent magnet assembly 119 through the two yokes 108. That is, FIG. 8 shows an excited state in which a magnetic field is generated on the first and second magnetic action surfaces and the magnetic body 135 can be attracted and held.

  In order to switch the excitation state in FIG. 8 to the non-excitation state, for example, the excitation coil 117 is energized so that the connection surface C1 becomes the S pole. Then, the connection surface C2 and the connection surface C3 become N poles. The N pole surface 121a of the permanent magnet assembly receives a magnetic repulsive force from the N pole of the connection surface C2 and the connection surface C3, and receives a magnetic attractive force from the S pole of the connection surface C1. Accordingly, the permanent magnet assembly 119 rotates 90 degrees clockwise in FIG. 8, the N pole surface 121a is magnetically connected to the S pole of the connection surface C1, and the S pole surface 122a is connected to the N pole of the connection surface C3. Magnetically connect and stop. This state is a non-excitation state of the magnetic circuit 100. After the permanent magnet assembly 119 is rotated, the non-excited state is maintained by the magnetic force of the permanent magnet even if the energization of the exciting coil 117 is stopped.

  In the non-excited state, the magnetic flux of the permanent magnet assembly 119 passes through the first yoke upper connection portion 104, upper plate portion 102, side plate portion 103, and lower connection portion 106 from the N pole surface 121a. Return to the S pole surface 122a of 119. That is, since the magnetic flux is short-circuited by the first yoke 101, a magnetic field is not generated on the first and second magnetic action surfaces, and the magnetic material cannot be attracted and held.

  In order to switch the non-excitation state to the excitation state, the excitation coil 118 is energized so that the connection surface C2 becomes the S pole. Then, the connection surface C1 and the connection surface C3 become N poles. The N pole surface 121a of the permanent magnet assembly receives a magnetic repulsive force from the N pole of the connection surface C1, and receives a magnetic attractive force from the S pole of the connection surface C2. Therefore, the permanent magnet assembly 119 rotates 90 degrees counterclockwise in FIG. 8, the N pole surface 121a is magnetically connected to the S pole of the connection surface C2, and the S pole surface 122a is magnetically connected to the connection surface E. Connect to and stop. This state is an excitation state of the magnetic circuit 100 shown in FIG. After the permanent magnet assembly 119 is rotated, the excited state is maintained by the magnetic force of the permanent magnet even if the energization to the exciting coil 118 is stopped.

  In the magnetic circuit 100, the rotation direction of the permanent magnet assembly 119 can be determined as described above by properly using energization to the excitation coil 117 and the excitation coil 118 when switching between the excited state and the non-excited state. Switching between the excited state and the non-excited state only requires energization of the exciting coil 117 and the exciting coil 118, so that the magnetic circuit 100 can be easily operated remotely. Further, the permanent magnet assembly 119 rotates instantaneously, and after the excitation state and the non-excitation state are switched, the excitation state and the non-excitation state are changed by the magnetic force of the permanent magnet 120 even if the excitation coil is not energized. Since it can be maintained stably, the energization of the exciting coil may be instantaneous, and the magnetic circuit 100 is a magnetic circuit with low power consumption.

  However, even after the magnetic circuit 100 is switched to the excited state, energization to the exciting coil 118 can be continued. Thereby, the magnetic field generated on the first and second magnetic action surfaces can be strengthened, and the magnetic body 135 can be attracted and held more strongly. Further, the magnetic field generated on the first and second magnetic acting surfaces can be weakened by weakly energizing the exciting coil 118 in the opposite direction.

  Further, since the permanent magnet assembly 119 only rotates around the central axis, and the permanent magnet assembly 119 does not collide with the connection surfaces C1, C2, C3, E, the permanent magnet 120 may be damaged. No. In particular, even if a permanent magnet that is excellent in magnetic properties such as a ferrite magnet or a rare earth magnet but is brittle in material is used, the permanent magnet 120 is not damaged.

  As described above, the excitation coil 117 and the excitation coil 118 are separately used for switching the excitation state and the non-excitation state of the magnetic circuit 100. However, both excitation coils can be used simultaneously. For example, in order to switch the excitation state of FIG. 8 to the non-excitation state, the excitation coil 117 is energized to make the connection surface C1 N pole, and at the same time, the excitation coil 118 is energized to make the connection surface C2 N pole. Then, the connection surface C3 becomes the S pole, the permanent magnet assembly 119 rotates 90 degrees counterclockwise, the N pole surface 121a is magnetically connected to the S pole of the connection surface C3, and the S pole surface 122a is connected. Magnetically connected to the north pole of surface C1 and stopped. This state is also a non-excited state of the magnetic circuit 100. At this time, energization to the excitation coil 117 and the excitation coil 118 causes the first magnetic action surface 107 to be the S pole, and thus exerts a magnetic field opposite to that when the magnetic body 135 is attracted and held, and magnetic The residual attractive force due to the magnetization of the body 135 can be offset and release can be facilitated.

  Further, in order to switch the non-excitation state to the excitation state, it is only necessary to energize the excitation coil 117 and the excitation coil 118 at the same time so that the connection surface C1 and the connection surface C2 become the S pole. Then, the connection surface C3 becomes an N pole, the permanent magnet assembly 119 rotates 90 degrees clockwise, the N pole surface 121a is magnetically connected to the connection surface C2, and the S pole surface 122a is magnetically connected to the connection surface E. The magnetic circuit 100 enters an excited state.

In addition, since the magnetic circuit 100 has two exciting coils, even if a failure occurs in one of the exciting coils, the remaining exciting coils can be used, and it is easy to deal with the failure.
The exciting coil may be disposed so as to surround the boundary portion between the side plate portion 103 and the lower connecting portion 106 of the first yoke 101, or may be disposed so as to surround the connecting surface E of the second yoke 108. Also good.

  In addition to lifting magnets, magnet bases, and magnet holders, the magnetic circuit of the present invention also applies magnetic fields such as magnet chucks, various magnetic adsorption and holding devices, magnetic sorters, magnetizing devices, magnetic processing devices, and magnetic repulsion force application devices. It is a magnetic circuit that can be used in many devices. When using the magnetic circuit of the present invention, the first yoke extension member magnetically connected only to the first yoke, or the second yoke extension member magnetically connected only to the second yoke. Either or both of them can be arranged, and a new shape magnetic action surface suitable for use can be formed by the yoke extension member.

It is sectional drawing (1-1 section of FIG. 2) of the perpendicular direction of Example 1 of the magnetic circuit of this invention, and has shown the excitation state. It is sectional drawing of the horizontal direction of Example 1 of the magnetic circuit of this invention (2-2 section of FIG. 1). It is sectional drawing of the perpendicular direction of Example 1 of the magnetic circuit of this invention, and has shown the non-excitation state. It is a front view of Example 1 of the magnetic circuit of the present invention. It is sectional drawing (5-5 section of FIG. 6) of the perpendicular direction of Example 2 of the magnetic circuit of this invention, and has shown the excitation state. FIG. 6 is a horizontal sectional view (cross section 6-6 in FIG. 5) of the magnetic circuit according to the second embodiment of the present invention. It is sectional drawing of the perpendicular direction of Example 2 of the magnetic circuit of this invention, and has shown the non-excitation state. It is sectional drawing of the perpendicular direction of Example 3 of the magnetic circuit of this invention, and has shown the excitation state.

Explanation of symbols

10, 50, 100: Magnetic circuit 11, 51, 101: First yoke 12, 55, 107: First magnetic working surface 13, 56, 108: Second yoke 14, 57, 109: Second magnetic Working surface 17, 64, 116: Cylindrical hole 20, 70, 120: Permanent magnet 69, 119: Permanent magnet assembly 71, 72, 121, 122: Magnetic pole member 23, 65, 117, 118: Excitation coil 15, 16, 61, 62, 63, 111, 112, 113, 114, 115: Separator 28, 29, 75, 76: Rotating shaft 32, 79: Handle 33, 34: Stopper

Claims (5)

  Surrounded by a first yoke having a first magnetic acting surface, a second yoke having a second magnetic acting surface and magnetically insulated from the first yoke, and the first and second yokes A permanent magnet or permanent magnet assembly rotatably arranged in the cylindrical hole formed, and an excitation coil, and energizing the excitation coil to rotate the permanent magnet or permanent magnet assembly to rotate the permanent magnet or permanent magnet. The magnetic connection between the magnetic pole surface of the magnet assembly and the connection surfaces of the first yoke and the second yoke exposed on the inner surface of the cylindrical hole is switched, and the first and second magnetic action surfaces are switched. A magnetic circuit that can be switched between an excited state where a magnetic field is generated and a non-excited state where a magnetic field is not generated. The first yoke has a connection surface A that is exposed at one location in the circumferential direction on the inner surface of the cylindrical hole, and the second yoke is a connection that is exposed at one location in the circumferential direction on the inner surface of the cylindrical hole. Surface E,
Energizing the exciting coil, one of the magnetic pole surfaces of the permanent magnet or permanent magnet assembly is connected to the connection surface A and the other magnetic pole surface is connected to the connection surface E, and both of the magnetic pole surfaces are connected The magnetic circuit according to claim 1, wherein the magnetic circuit can be switched to a non-excited state connected to both surfaces A and E.   The first yoke has connection surfaces B1 and B2 exposed at two locations in the circumferential direction on the inner surface of the cylindrical hole, and the second yoke is exposed at one location in the circumferential direction on the inner surface of the cylindrical hole. A connection surface E to be energized, energizing the exciting coil, one magnetic pole surface of the permanent magnet or permanent magnet assembly is connected to either the connection surface B1 or B2, and the other magnetic pole surface is connected to the connection surface E. It is possible to switch between an excitation state to be performed and a non-excitation state in which one magnetic pole surface is connected to one of the connection surfaces B1 or B2 and the other magnetic pole surface is connected to the other of the connection surfaces B1 or B2. The magnetic circuit according to claim 1.   The first yoke has connection surfaces C1, C2, and C3 exposed at three locations in the circumferential direction on the inner surface of the cylindrical hole, and the second yoke is located at one location in the circumferential direction on the inner surface of the cylindrical hole. And the exciting coil is energized so that one of the magnetic pole surfaces of the permanent magnet or permanent magnet assembly is connected to one of the connecting surfaces C1, C2 or C3, and the other magnetic pole. An excitation state in which the surface is connected to the connection surface E, one magnetic pole surface is connected to any one of the connection surfaces C1, C2, or C3, and the other magnetic pole surface is one of the remaining two connection surfaces. The magnetic circuit according to claim 1, wherein the magnetic circuit can be switched to a non-excitation state connected to one. The magnetic circuit according to any one of claims 1 to 4, wherein a rotating shaft portion is disposed in the permanent magnet or the permanent magnet assembly.

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