JP2018163996A - Actuator and magnetic circuit - Google Patents

Abstract

An actuator having two magnetic path members that can be attracted and released is designed to reduce electric power when two magnetic path members are attracted. An actuator (10) includes a first magnetic path member (12), a second magnetic path member (14) capable of being attracted to and released from the first magnetic path member (12), a variable permanent magnet (18), a coil (16), and a release spring. 26 and a bypass magnetic path member 24 . The bypass magnetic path member 24 forms a parallel magnetic path with the variable permanent magnet 18 when the second magnetic path member is in the open state. When current is applied to the coil 16 while the second magnetic path member 14 is in the open state, the magnetic flux passes through a path including the detour magnetic path member 24 having a lower magnetic resistance than the path through the variable permanent magnet 18 . Since the magnetic flux passes through a path with low reluctance, the power required to generate the required magnetic force can be reduced. [Selection drawing] Fig. 1

Description

  The present invention relates to an actuator that operates using the magnetic force of an electromagnet and a permanent magnet, and a magnetic circuit that can be used for the actuator.

  There is known an actuator that attracts and releases two magnetic path members by using the magnetic force of an electromagnet and a permanent magnet. Patent Document 1 below shows a first magnetic path member (yoke 13) and a second magnetic path member (31) that is attracted and released by the first magnetic path member (13). The second magnetic path member (31) is maintained in the attracted state by the magnetic force of the first and second permanent magnets (16, 17). When the second magnetic path member (31) is in the attracted state, the magnetism of the second permanent magnet (17) is reversed by the pulsed energization of the coil (11), and the second magnetic path member (31). The power to adsorb is lost. Then, the second magnetic path member (31) is released from the first magnetic path member (13) by the release spring (32). When the second magnetic path member (31) is in the released state, a pulsed current opposite to the direction when the coil (11) is released is passed. By this energization, the polarity of the permanent magnet (17) is reversed and the second magnetic path member (31) is attracted to the first magnetic path member (13). In addition, the term and code | symbol in () are the term and code | symbol used by the following patent document 1. FIG. These codes are not related to the codes used in the description of the embodiment of the present application.

JP-A-1-303331

  The permanent magnet has a large magnetic resistance, and it is necessary to pass a large current through the coil in order to pass the magnetic flux through the permanent magnet.

  An object of this invention is to reduce the electric power at the time of adsorb | sucking two magnetic path members.

  The actuator according to the present invention has a first magnetic path member, a second magnetic path member that can be attracted and released to the first magnetic path member, and a second magnetic path member that is attracted to the first magnetic path member by a magnetic force. A first permanent magnet, a coil for generating a magnetic flux in a magnetic circuit including the first magnetic path member, the second magnetic path member, and the first permanent magnet; and a second magnetic path member in a direction to be released from the first magnetic path member. In a state where the urging release spring and the second magnetic path member are released from the first magnetic path member, a magnetic path parallel to the first permanent magnet is formed, and the second magnetic path member is the first magnetic path. And a detour magnetic path member arranged so as not to form a magnetic path in parallel with the first permanent magnet in the state of being attracted to the path member. In the first permanent magnet, when the second magnetic path member is released, the magnetic flux density is irreversibly lowered as compared with when the first permanent magnet is attracted. In a state where the second magnetic path member is released from the first magnetic path member, the magnetic flux generated by the coil bypasses the first permanent magnet and passes through the bypass magnetic path member.

  A magnetic circuit according to another aspect of the present invention includes a first magnetic path member, a second magnetic path member that can be attracted to and released from the first magnetic path member, and the second magnetic path member by a magnetic force. In a state where the first permanent magnet to be attracted to the path member and the second magnetic path member are released from the first magnetic path member, a magnetic path parallel to the first permanent magnet is formed, and the second magnetic path member Has a detoured first magnetic path member arranged so as not to form a magnetic path in parallel with the first permanent magnet in a state where is adsorbed to the first magnetic path member. In the first permanent magnet, when the second magnetic path member is released, the magnetic flux density is irreversibly lowered as compared with when the first permanent magnet is attracted. In a state where the second magnetic path member is released from the first magnetic path member, the magnetic flux generated in the magnetic circuit bypasses the first permanent magnet and passes through the bypass magnetic path member.

  Further, the first permanent magnet may be disposed in the second magnetic path member so as to move together with the second magnetic path member, and the bypass magnetic path member may be fixedly disposed.

  Moreover, it can further have the 2nd permanent magnet contained in the magnetic circuit containing a 1st magnetic path member, a 2nd magnetic path member, and a 1st permanent magnet. In a state where the second magnetic path member is attracted to the first magnetic path member, the second permanent magnet is in parallel with the first permanent magnet and causes the second magnetic path member to be attracted to the first magnetic path member by a magnetic force. When the second magnetic path member is released from the first magnetic path member, the polarity is reversed by the magnetic flux of the second permanent magnet, and the magnetic field does not act on the second magnetic path member because it is in series with the first permanent magnet. .

  Further, the magnetic flux density of the first permanent magnet is irreversibly lowered by releasing the second magnetic path member from the first magnetic path member.

  By providing the detour magnetic path member, when the second magnetic path member is released from the first magnetic path member, the magnetic resistance of the magnetic path along the magnetic flux generated in the first and second magnetic path members is reduced. The power for adsorbing the second magnetic path member can be reduced.

It is a schematic diagram which shows schematic structure of the actuator of this embodiment. It is a schematic diagram which shows schematic structure of the actuator of other embodiment. It is a schematic diagram which shows schematic structure of the actuator of other embodiment. It is a schematic diagram which shows schematic structure of the actuator of other embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating a configuration of an actuator 10 according to the present embodiment. (A) shows a state where the second magnetic path member 14 is attracted to and joined to the first magnetic path member 12 (hereinafter referred to as “attracted state”), and (b) shows the first magnetic path. The second magnetic path member 14 is released from the member 12 and is separated (hereinafter referred to as “released state”). (C) is a figure which shows the state which is operate | moving so that the 2nd magnetic path member 14 of a released state may be adsorb | sucked.

  The first magnetic path member 12 is substantially U-shaped, and a coil 16 is disposed inside the U-shape. A current flows through the coil 16 in a direction penetrating the paper surface of FIG. The second magnetic path member 14 can be attracted to and released from the first magnetic path member 12. The second magnetic path member 14 includes a first magnetic path piece 14 </ b> A and a second magnetic path piece 14 </ b> B respectively corresponding to the U-shaped ends of the first magnetic path member 12. The first magnetic path piece 14A and the second magnetic path piece 14B are substantially linear or substantially flat. The first magnetic path piece 14A is opposed to one end of the U-shape of the first magnetic path member 12, and the second magnetic path piece 14B is opposed to the other end. When the second magnetic path member 14 is attracted to the first magnetic path member 12, the first magnetic path piece 14A is joined to one end of the U shape, and the second magnetic path piece 14B is joined to the other end. A permanent magnet 18 is disposed between the first magnetic path piece 14A and the second magnetic path piece 14B, and these are integrated. The permanent magnet 18 is a magnet that has a small holding force and can easily reverse the polarity. Hereinafter, the permanent magnet 18 is referred to as a variable permanent magnet 18. The variable permanent magnet 18 can be an alnico magnet, for example. When the second magnetic path member 14 is attracted to the first magnetic path member 12, a closed circuit is formed by the first magnetic path member 12, the second magnetic path member 14, and the variable permanent magnet 18. The coil 16 passes through the inside of this closed circuit.

  The first magnetic path piece 14A and the second magnetic path piece 14B extend beyond the variable permanent magnet 18 to the opposite side of the first magnetic path member 12. A portion extending beyond the variable permanent magnet 18 is referred to as a rear extension 22. A rear extension belonging to the first magnetic path piece 14A is indicated by 22A, and a rear extension belonging to the second magnetic path piece 14B is indicated by 22B. When the second magnetic path member 14 is released (see (b)), the bypass magnetic path member 24 is disposed at a position between the rear extension portions 22A and 22B. The bypass magnetic path member 24 is disposed so as not to change its position relative to the first magnetic path member 12.

The second magnetic path member 14 is urged by a release spring 26 in a direction away from the first magnetic path member 12. The urging force of the release spring 26 is referred to as “ _FE ”. The coil 16 can generate a magnetic flux in a magnetic circuit formed by the first magnetic path member 12, the second magnetic path member 14, the variable permanent magnet 18, and the bypass magnetic path member 24.

When the second magnetic path member 14 is in the attracted state, the variable permanent magnet 18 holds a magnetic force because the magnetic path is closed. The magnetic force that acts to attract the second magnetic path member 14 to the first magnetic path member 12 is referred to as “F _M ”. The magnetic force F _M overcomes the biasing force F _E of the release spring 26, the second magnetic path member 14 is maintained in the suction state. The magnetic flux generated by the variable permanent magnet 18 when the second magnetic path member 14 is in the attracted state is indicated by “Φ _M ”.

When the second magnetic path member 14 is in the attracted state, the second magnetic path member 14 is released when a current that generates a magnetic flux in a direction opposite to the magnetic flux Φ _M by the variable permanent magnet 18 is passed through the coil 16. . When the opposite magnetic flux is generated by the coil 16, the magnetic flux cancels at least a part of the magnetic flux Φ _M. That is, in FIG. 1, a current is passed through the coil 16 in a direction penetrating the paper surface from the back side to the front side to generate a magnetic flux in the magnetic path formed by the first magnetic path member 12 and the second magnetic path member 14, thereby making the variable The magnetic flux Φ _M by the permanent magnet 18 is reduced. As the magnetic flux Φ _M decreases, the magnetic force F _M decreases, the biasing force F _E of the release spring 26 exceeds the magnetic force F _M , and the second magnetic path member 14 is released from the first magnetic path member 12. When the second magnetic path member 14 is released, the magnetic path is opened, the magnetic flux Φ _M is decreased, and the variable permanent magnet 18 is demagnetized. That is, the variable permanent magnet 18 is a magnet having a characteristic of demagnetizing when the magnetic path is opened, and the magnetic flux density is irreversibly lowered when the second magnetic path member 14 is released. In order to prevent the magnetic flux of the variable permanent magnet 18 from being formed so as to pass through the bypass magnetic path member 24 when the second magnetic path member 14 is released, the first magnetic path piece 14A and the bypass magnet A gap is provided between the path member 24 and the second magnetic path piece 14B and the bypass magnetic path member 24 to increase the magnetic resistance. The variable permanent magnet 18 can be demagnetized by a magnetic flux generated by energization of the coil 16.

When the second magnetic path member 14 is in a released state or a magnetic force F _M is small, or zero, a state won biasing force F _E of the release spring 26. At this time, even if the coil 16 is not energized, the released state of the second magnetic path member 14 is maintained. Further, even if the second magnetic path member 14 approaches the first magnetic path member 12 by an external force such as vibration, because the magnetic force F _M is small, the first magnetic path member 12 of the second magnetic path member 14 Adsorption is suppressed. Moreover, adhesion of foreign substances such as iron powder to the second magnetic path member 14 can also be suppressed.

In order to bring the second magnetic path member 14 into the attracted state again, a current flowing from the front side to the back side of the paper is passed through the coil 16. The magnetic flux Φ _E generated by this current passes through a path including the bypass magnetic path member 24 whose magnetic resistance is smaller than the path through the variable permanent magnet 18 (indicated by a one-dot chain line in (c)). The detour magnetic path member 24 is arranged so as to form a magnetic path in parallel with the variable permanent magnet 18, and actually the magnetic flux according to the magnetic resistance that changes according to the attracted state and the released state of the second magnetic path member 14. The route to go through is determined. When the magnetic force F _M generated by the magnetic flux Φ _E is larger than the urging force F _E of the release spring 26, the second magnetic path member 14 is attracted to the first magnetic path member 12. In addition, the variable permanent magnet 18 is magnetized again by the magnetic flux Φ _E generated by passing a current through the coil 16, and a magnetic flux Φ _M is generated by the variable permanent magnet 18. If the second magnetic path member 14 is attracted and the magnetic flux Φ _M is generated by the variable permanent magnet 18, the magnetic flux Φ _M of the variable permanent magnet 18 is maintained without the magnetic flux Φ _E by the coil. Therefore, the variable permanent magnet 18 does not cause self-demagnetization, the magnetic force is maintained, and the attracted state is maintained.

The actuator 10 operates when a current is supplied to the coil 16 when the second magnetic path member 14 is attracted and released, and it is not necessary to apply a current to the coil 16 in order to maintain the attracted state and the released state. Further, when releasing the second magnetic path member 14, it is not necessary to reverse the magnetism of the variable permanent magnet 18, and the current flowing through the coil 16 to release the second magnetic path member 14 can be suppressed. Further, when the suction of the second magnetic path member 14, a lower path of reluctance through the bypass magnetic path member 24 for the passage of the magnetic flux [Phi _E, a small current, it is possible to generate a magnetic force F _M required.

  FIG. 2 is a schematic diagram illustrating a configuration of an actuator 30 according to another embodiment. (A) shows a state where the second magnetic path member 34 is attracted to and joined to the first magnetic path member 32 (hereinafter referred to as “attracted state”), and (b) shows the first magnetic path. The second magnetic path member 34 is released from the member 32 and is separated (hereinafter referred to as “released state”). (C) is a figure which shows the state which is operate | moving so that the 2nd magnetic path member 34 of a releasing state may be adsorb | sucked.

  The first magnetic path member 32 is substantially linear or flat. The second magnetic path member 34 can be attracted to and released from the first magnetic path member 32. The second magnetic path member 34 includes a first magnetic path piece 34 </ b> A and a second magnetic path piece 34 </ b> B that respectively correspond to the linear ends of the first magnetic path member 32. Each of the first magnetic path piece 34A and the second magnetic path piece 34B has a substantially linear shape or a substantially flat plate shape. The first magnetic path piece 34A faces the side of one end of the first magnetic path member 32, and the second magnetic path piece 34B faces the side of the other end. A coil 36 and two permanent magnets 38 and 40 are disposed between the first magnetic path piece 34A and the second magnetic path piece 34B. The two permanent magnets 38 and 40 are arranged so as to sandwich the coil 36, and both ends thereof are in contact with the first magnetic path piece 34A and the second magnetic path piece 34B, respectively. The first and second magnetic path pieces 34A and 34B and the two permanent magnets 38 and 40 may move together, and the coil 36 may move integrally therewith or may be fixed. When the second magnetic path member 34 is attracted to the first magnetic path member 32, the first magnetic path piece 34A is joined to one end of the first magnetic path member 32, and the second magnetic path piece 34B is joined to the other end. . A current flows through the coil 36 in a direction penetrating the paper surface of FIG. One permanent magnet 38 has a small holding force and can easily reverse the polarity. Hereinafter, the permanent magnet 38 is referred to as a variable permanent magnet 38. The variable permanent magnet 38 can be, for example, an alnico magnet. The other permanent magnet 40 is a magnet that has a large holding force and cannot easily reverse its polarity. Hereinafter, the permanent magnet 40 is referred to as a fixed permanent magnet 40. The fixed permanent magnet 40 can be a neodymium magnet, for example.

  The first magnetic path piece 34A and the second magnetic path piece 34B extend beyond the variable permanent magnet 38 to the opposite side of the first magnetic path member 32. The portions extending beyond the variable permanent magnet 38 are referred to as rear extension portions 42A and 42B. A rear extension belonging to the first magnetic path piece 34A is indicated by 42A, and a rear extension belonging to the second magnetic path piece 34B is indicated by 42B. When the second magnetic path member 34 is released (see (b)), the detour magnetic path member 44 is disposed at a position between the rear extension portions 42A and 42B.

The bypass magnetic path member 44 is disposed so as not to change its position relative to the first magnetic path member 32. The second magnetic path member 34 is biased in a direction away from the first magnetic path member 32 by a release spring 46. The urging force of the release spring 46 is referred to as “ _FE ”. The coil 36 can generate a magnetic flux in a magnetic circuit formed by the first magnetic path member 32, the second magnetic path member 34, the variable permanent magnet 38, or the detour magnetic path member 44.

When the second magnetic path member 34 is attracted to the first magnetic path member 32, a closed magnetic circuit is formed by the first and second magnetic path members 32, 34, the variable permanent magnet 38, and the fixed permanent magnet 40. . The magnetic flux Φ _M1 generated by the variable permanent magnet 38 passes through a magnetic path formed by the second magnetic path piece 34B, the first magnetic path member 32, and the second magnetic path piece 34A. The magnetic flux Φ _M2 generated by the fixed permanent magnet 40 also passes through the magnetic path formed by the second magnetic path piece 34B, the first magnetic path member 32, and the second magnetic path piece 34A. The magnetic flux Φ _M1 and the magnetic flux Φ _M2 are parallel to each other, and the variable permanent magnet 38 and the fixed permanent magnet 40 are arranged in parallel when the second magnetic path member 34 is attracted to the first magnetic path member 32. . Further, when the second magnetic path member 34 is attracted to the first magnetic path member 32, the magnetic flux Φ _M1 of the variable permanent magnet 38 is maintained, so that the variable permanent magnet 38 does not cause self-demagnetization and maintains the magnetic force. doing.

The magnetic force that acts to attract the second magnetic path member 34 to the first magnetic path member 32 will be referred to as “F _M ”. The magnetic force F _M overcomes the biasing force F _E of the release spring 46, the second magnetic path member 14 is maintained in the suction state.

When the second magnetic path member 34 is in the attracted state, the second magnetic path member 34 is released when a current that generates a magnetic flux in a direction opposite to the magnetic flux Φ _M1 by the variable permanent magnet 38 is passed through the coil 36. When the opposite magnetic flux is generated by the coil 36, the magnetic flux cancels at least a part of the magnetic flux Φ _M1 . That is, in FIG. 2, a current is passed through the coil 36 in a direction penetrating the paper surface from the back side to the front side to generate a magnetic flux in the magnetic path formed by the first magnetic path member 32 and the second magnetic path member 34. The magnetic flux Φ _M1 by the permanent magnet 38 is reduced. As the magnetic flux Φ _M1 decreases, the magnetic force F _M decreases, the urging force F _E of the release spring 46 exceeds the magnetic force F _M , and the second magnetic path member 34 is released from the first magnetic path member 32. When the second magnetic path member 34 is released, the magnetic path is opened, the magnetic flux Φ _M1 is decreased, and the variable permanent magnet 38 is demagnetized. That is, the variable permanent magnet 38 is a magnet having a characteristic of demagnetizing when the magnetic path is opened, and the magnetic flux density is irreversibly lowered when the second magnetic path member 34 is released. In order to prevent the magnetic flux passing through the bypass magnetic path member 44 from being formed and the magnetic flux of the variable permanent magnet 38 being maintained when the second magnetic path member 34 is released, the first magnetic path piece 34A. Further, a gap is provided between the bypass magnetic path member 44 and the second magnetic path piece 34B and the bypass magnetic path member 44 to increase the magnetic resistance. When the second magnetic path member 34 is in the released state, a gap is formed between the first magnetic path member 32 and the magnetic resistance due to this gap is set to be greater than the magnetic resistance of the variable permanent magnet 38. . As a result, the magnetic flux generated by the fixed permanent magnet 40 acts on the variable permanent magnet 38, and the magnetism of the variable permanent magnet 38 is reversed. The variable permanent magnet 38 and the fixed permanent magnet 40 form a common magnetic flux Φ _M1 , ₂ and are arranged in series when the second magnetic path member 34 is released. The magnetic flux Φ _M1 , ₂ does not cause the variable permanent magnet 38 to self-demagnetize and maintain the magnetic force. The variable permanent magnet 38 can be demagnetized by a magnetic flux generated by energization of the coil 36.

When the second magnetic path member 34 is in the released state, the magnetic flux [Phi _{M1, 2} remains in the second magnetic path member 34, little interaction with the first magnetic path member 32, the magnetic force F _M is reduced, The biasing force F _E of the release spring 46 has been won. At this time, the released state of the second magnetic path member 34 is maintained even if the coil 36 is not energized. Further, even if the second magnetic path member 34 approaches the first magnetic path member 32 by an external force such as vibration, because the magnetic force F _M is small, the first magnetic path member 32 of the second magnetic path member 34 Adsorption is suppressed. Moreover, adhesion of foreign substances such as iron powder to the second magnetic path member 34 can also be suppressed.

In order to bring the second magnetic path member 34 into the attracted state again, a current flowing from the front side to the back side of the paper is passed through the coil 36. The magnetic flux Φ _E generated by this current passes through the bypass magnetic path member 44 having a smaller magnetic resistance than the path through the variable permanent magnet 38. The detour magnetic path member 44 is arranged so as to form a magnetic path in parallel with the variable permanent magnet 38, and actually the magnetic flux according to the magnetic resistance that changes according to the attracted state and the released state of the second magnetic path member 34. The route to go through is determined. When the magnetic force F _M generated by the magnetic flux Φ _E is larger than the biasing force F _E of the release spring 46, the second magnetic path member 34 is attracted to the first magnetic path member 32. In addition, the variable permanent magnet 38 is magnetized again by the magnetic flux Φ _E generated by passing a current through the coil 36, and a magnetic flux Φ _M1 is generated by the variable permanent magnet 38. If the second magnetic path member 34 is attracted and the magnetic flux Φ _M1 is generated by the variable permanent magnet 38, the magnetic flux Φ _M1 of the variable permanent magnet 38 is maintained without the magnetic flux Φ _E by the coil 36. Therefore, the variable permanent magnet 38 does not cause self-demagnetization, the magnetic force is maintained, and the attracted state is maintained.

  The bypass magnetic path member 44 may be fixed, and the second magnetic path member 34 may be moved while being in contact with the fixed bypass magnetic path member 44.

  FIG. 3 is a schematic diagram illustrating a configuration of an actuator 50 according to still another embodiment. (A) shows a state where the second magnetic path member 54 is attracted to and joined to the first magnetic path member 52 (hereinafter referred to as “attracted state”), and (b) shows the first magnetic path. The second magnetic path member 54 is released from the member 52 and separated (hereinafter referred to as “released state”). (C) is a figure which shows the state which is operate | moving so that the 2nd magnetic path member 54 of a releasing state may be adsorb | sucked.

  The first magnetic path member 52 is substantially U-shaped, and a coil 56 is disposed inside the U-shape. A current flows through the coil 56 in a direction penetrating the paper surface of FIG. The second magnetic path member 54 has a substantially linear shape or a substantially flat plate shape and can be attracted to and released from the first magnetic path member 52. The second magnetic path member 54 is arranged so as to bridge the U-shaped ends of the first magnetic path member 52 when attracted to the first magnetic path member 52. A permanent magnet 58 is arranged on one side of the U-shape of the first magnetic path member 52 so that the direction connecting both poles is along the one side of the U-shape. The permanent magnet 58 is a magnet that has a small holding force and can easily reverse the polarity. Hereinafter, the permanent magnet 58 is referred to as a variable permanent magnet 58. The variable permanent magnet 58 can be, for example, an alnico magnet. When the second magnetic path member 54 is attracted to the first magnetic path member 52, a closed circuit is formed by the first magnetic path member 52, the second magnetic path member 54, and the variable permanent magnet 58. The coil 56 passes through the inside of this closed circuit.

  The detour magnetic path member 64 is disposed in parallel with the side of the first magnetic path member 52 where the variable permanent magnet 58 is disposed. In this actuator 50, the bypass magnetic path member 64 is formed integrally with the second magnetic path member 54 and has a substantially L shape as a whole. The tip 64a of the bypass magnetic path member 64 faces the portion of the first magnetic path member 52 that is closer to the root than the variable permanent magnet 58, even when the second magnetic path member 54 is released and moved (see (b)). To be arranged.

The second magnetic path member 54 is biased in a direction away from the first magnetic path member 52 by a release spring 66. The urging force of the release spring 66 is referred to as “ _FE ”. The coil 56 can generate a magnetic flux in a magnetic circuit formed by the first magnetic path member 52, the second magnetic path member 54, the variable permanent magnet 58, or the detour magnetic path member 64.

When the second magnetic path member 54 is in the attracted state, the variable permanent magnet 58 holds the magnetic force because the magnetic path is closed. The magnetic force that acts to attract the second magnetic path member 54 to the first magnetic path member 52 is denoted as “F _M ”. The magnetic force F _M overcomes the biasing force F _E of the release spring 66, the second magnetic path member 54 is maintained in the suction state. The magnetic flux generated by the variable permanent magnet 58 when the second magnetic path member 54 is in the attracted state is indicated by “Φ _M ”.

When the second magnetic path member 54 is in the attracted state, the second magnetic path member 54 is released when a current that generates a magnetic flux in a direction opposite to the magnetic flux Φ _M by the variable permanent magnet 58 is passed through the coil 56. . When the opposite magnetic flux is generated by the coil 56, the magnetic flux cancels at least a part of the magnetic flux Φ _M. That is, in FIG. 3, a current is passed through the coil 56 in a direction passing through the paper surface from the front side to the back side to generate a magnetic flux in the magnetic path formed by the first magnetic path member 52 and the second magnetic path member 54, thereby making the variable The magnetic flux Φ _M by the permanent magnet 58 is reduced. At this time, the magnetic path of the path passing through the bypass magnetic path member 64 is made larger by the gap between the tip 64a and the first magnetic path member 52 than the magnetic resistance of the path passing through the variable permanent magnet 58, The magnetic flux generated by the coil 56 does not pass through the bypass magnetic path member 64 but passes through the variable permanent magnet 58. As the magnetic flux Φ _M decreases, the urging force F _E of the release spring 66 exceeds the magnetic force F _M , and the second magnetic path member 54 is released from the first magnetic path member 52. When the second magnetic path member 54 is released, the magnetic path is opened, the magnetic flux Φ _M is decreased, and the variable permanent magnet 68 is demagnetized. That is, the variable permanent magnet 68 is a magnet having a characteristic of demagnetizing when the magnetic path is opened, and the magnetic flux density is irreversibly lowered when the second magnetic path member 54 is released. Note that the variable permanent magnet 58 can be demagnetized by a magnetic flux generated by energization of the coil 56.

When the second magnetic path member 54 is in the released state or the magnetic force F _M is small, or zero, a state won biasing force F _E of the release spring 66. At this time, even if the coil 56 is not energized, the released state of the second magnetic path member 54 is maintained. Further, even if the second magnetic path member 54 approaches the first magnetic path member 52 by an external force such as vibration, because the magnetic force F _M is small, the first magnetic path member 52 of the second magnetic path member 54 Adsorption is suppressed. Moreover, adhesion of foreign substances such as iron powder to the second magnetic path member 54 can also be suppressed.

In order to bring the second magnetic path member 54 into the attracted state again, a current flowing from the back side to the front side of the paper is passed through the coil 56. The magnetic flux Φ _E generated by this current passes through a path including a bypass magnetic path member 64 in which the magnetic resistance is made smaller than the path through the variable permanent magnet 58 (indicated by a one-dot chain line in (c)). The detour magnetic path member 64 is arranged so as to form a magnetic path in parallel with the variable permanent magnet 58, and the magnetic flux actually varies according to the magnetic resistance that changes according to the attracted state and the released state of the second magnetic path member 54. The route to go through is determined. When the magnetic force F _M generated by the magnetic flux Φ _E is larger than the biasing force F _E of the release spring 66, the second magnetic path member 54 is attracted to the first magnetic path member 52. In addition, the variable permanent magnet 58 is magnetized again by the magnetic flux Φ _E generated by passing a current through the coil 56, and a magnetic flux Φ _M is generated by the variable permanent magnet 58. If the second magnetic path member 54 is attracted and the magnetic flux Φ _M is generated by the variable permanent magnet 58, the magnetic flux Φ _M of the variable permanent magnet 58 is maintained without the magnetic flux Φ _E by the coil. Therefore, the variable permanent magnet 58 does not cause self-demagnetization, the magnetic force is maintained, and the attracted state is maintained.

The actuator 50 operates when a current is passed through the coil 56 when the second magnetic path member 54 is attracted and released, and it is not necessary to pass a current through the coil 56 in order to maintain the attracted state and the released state. Further, when releasing the second magnetic path member 54, it is not necessary to reverse the magnetism of the variable permanent magnet 58, and the current flowing through the coil 56 in order to release the second magnetic path member 54 can be suppressed. Further, when the suction of the second magnetic path member 54, a lower path of reluctance through the bypass magnetic path member 64 for the passage of the magnetic flux [Phi _E, a small current, it is possible to generate a magnetic force F _M required.

  FIG. 2 is a schematic diagram illustrating a configuration of an actuator 70 according to another embodiment. (A) shows a state where the second magnetic path member 74 is attracted to and joined to the first magnetic path member 72 (hereinafter referred to as “attracted state”), and (b) shows the first magnetic path. The second magnetic path member 74 is released from the member 72 and separated (hereinafter referred to as “released state”). (C) is a figure which shows the state which is operate | moving so that the 2nd magnetic path member 74 of a releasing state may be adsorb | sucked.

  The first magnetic path member 72 is substantially U-shaped, and a coil 76 is disposed inside the U-shape. A current flows through the coil 76 in a direction penetrating the paper surface of FIG. The second magnetic path member 74 has a substantially linear shape or a substantially flat plate shape and can be attracted to and released from the first magnetic path member 72. The second magnetic path member 74 is disposed so as to bridge both U-shaped ends of the first magnetic path member 72 when attracted to the first magnetic path member 72. A permanent magnet 78 is disposed on one side of the U-shape of the first magnetic path member 72 so that the direction connecting both poles is along the one side of the U-shape. The permanent magnet 78 is a magnet that has a small holding force and can easily reverse the polarity. Hereinafter, the permanent magnet 78 is referred to as a variable permanent magnet 78. The variable permanent magnet 78 can be, for example, an alnico magnet. The actuator 70 further includes a permanent magnet 80. The permanent magnet 80 is disposed between the U-shaped tip portions of the first magnetic path member 72, and both ends thereof are in contact with the U-shaped tip portions. The permanent magnet 80 is a magnet that has a large holding force and cannot easily reverse its polarity. Hereinafter, the permanent magnet 80 is referred to as a fixed permanent magnet 80. The fixed permanent magnet 80 can be a neodymium magnet, for example. The first magnetic path member 72, the variable permanent magnet 78, and the fixed permanent magnet 80 may move together, and the coil 76 may move integrally therewith or may be fixed.

  The detour magnetic path member 84 is disposed in parallel with the side of the first magnetic path member 72 where the variable permanent magnet 78 is disposed. In this actuator 70, the bypass magnetic path member 84 is formed integrally with the second magnetic path member 74, and has a substantially L shape as a whole. The tip 84a of the bypass magnetic path member 84 faces the portion of the first magnetic path member 72 that is closer to the root than the variable permanent magnet 78, even if the second magnetic path member 74 is released and moved (see (b)). To be arranged.

The second magnetic path member 74 is biased in a direction away from the first magnetic path member 72 by a release spring 86. The urging force of the release spring 86 is referred to as “ _FE ”. The coil 76 can generate a magnetic flux in a magnetic circuit formed by the first magnetic path member 72, the second magnetic path member 74, the variable permanent magnet 78 or the detour magnetic path member 64.

When the second magnetic path member 74 is attracted to the first magnetic path member 72, a closed magnetic circuit is formed by the first and second magnetic path members 72 and 74, the variable permanent magnet 78, and the fixed permanent magnet 80. . The magnetic flux Φ _M1 generated by the variable permanent magnet 78 passes through a magnetic path formed by the first magnetic path member 72 and the second magnetic path member 74. The magnetic flux Φ _M2 generated by the fixed permanent magnet 80 also passes through the magnetic path formed by the first magnetic path member 72 and the second magnetic path member 74. The magnetic flux Φ _M1 and the magnetic flux Φ _M2 are parallel, and the variable permanent magnet 78 and the fixed permanent magnet 80 are arranged in parallel when the second magnetic path member 74 is attracted to the first magnetic path member 72. . When the second magnetic path member 74 is attracted to the first magnetic path member 72, the magnetic flux Φ _M1 of the variable permanent magnet 78 is maintained, so that the variable permanent magnet 78 does not cause self-demagnetization and maintains magnetic force. doing.

When the second magnetic path member 74 is in the attracted state, the second magnetic path member 74 is released when a current that generates a magnetic flux in a direction opposite to the magnetic flux Φ _M1 by the variable permanent magnet 78 is passed through the coil 76. When the opposite magnetic flux is generated by the coil 76, the magnetic flux cancels at least a part of the magnetic flux Φ _M1 . That is, in FIG. 4, a current is passed through the coil 16 in a direction passing through the paper surface from the back side to the front side to generate a magnetic flux in the magnetic path formed by the first magnetic path member 72 and the second magnetic path member 74, thereby making the variable The magnetic flux Φ _M1 by the permanent magnet 78 is reduced. At this time, the magnetic path of the path passing through the bypass magnetic path member 64 is made larger by the gap between the tip 64a and the first magnetic path member 52 than the magnetic resistance of the path passing through the variable permanent magnet 78, The magnetic flux generated by the coil 56 does not pass through the bypass magnetic path member 64 but passes through the variable permanent magnet 58. As the magnetic flux Φ _M1 decreases, the urging force F _E of the release spring 86 exceeds the magnetic force F _M , and the second magnetic path member 74 is released from the first magnetic path member 72. When the second magnetic path member 74 is released, the magnetic path is opened, the magnetic flux Φ _M1 is decreased, and the variable permanent magnet 78 is demagnetized. That is, the variable permanent magnet 78 is a magnet having a characteristic of demagnetizing when the magnetic path is opened, and the magnetic flux density is irreversibly lowered when the second magnetic path member 54 is released. In order to prevent the magnetic path of the detour magnetic path member 44 from being formed and the magnetic flux of the variable permanent magnet 38 being maintained when the second magnetic path member 74 is released, the first magnetic path member A gap is provided between 72 and the tip end portion 84a of the detour magnetic path member 84 to increase the magnetic resistance. When the second magnetic path member 74 is in the released state, a gap is formed between the second magnetic path member 74 and the first magnetic path member 72, and the magnetic resistance due to this gap is set to be greater than the magnetic resistance of the variable permanent magnet 78. . As a result, the magnetic flux generated by the fixed permanent magnet 80 acts on the variable permanent magnet 78, and the magnetism of the variable permanent magnet 78 is reversed. The variable permanent magnet 78 and the fixed permanent magnet 80 form a magnetic flux Φ _M1 , ₂ and are in a series state when the second magnetic path member 74 is released. The magnetic flux Φ _M1 , ₂ does not cause the variable permanent magnet 78 to self-demagnetize and maintain the magnetic force. The variable permanent magnet 78 can be demagnetized by a magnetic flux generated by energization of the coil 76.

When the second magnetic path member 74 is in the released state, the magnetic flux [Phi _{M1, 2} remains in the second magnetic path member 74, since hardly interact with the first magnetic path member 72, the magnetic force F _M is reduced, The biasing force F _E of the release spring 86 has been won. At this time, the released state of the second magnetic path member 74 is maintained even when the coil 76 is not energized. Further, even if the second magnetic path member 74 approaches the first magnetic path member 72 by an external force such as vibration, because the magnetic force F _M is small, the first magnetic path member 72 of the second magnetic path member 74 Adsorption is suppressed. Moreover, adhesion of foreign substances such as iron powder to the second magnetic path member 74 can also be suppressed.

In order to bring the second magnetic path member 74 into the attracted state again, a current flowing from the front side to the back side of the paper is passed through the coil 76. The magnetic flux Φ _E generated by this current passes through the bypass magnetic path member 84 whose magnetic resistance is smaller than the path through the variable permanent magnet 78. The detour magnetic path member 84 is disposed so as to form a magnetic path in parallel with the variable permanent magnet 78, and actually the magnetic flux according to the magnetic resistance that changes according to the attracted state and the released state of the second magnetic path member 74. The route to go through is determined. When the magnetic force F _M generated by the magnetic flux Φ _E is larger than the urging force F _E of the release spring 86, the second magnetic path member 74 is attracted to the first magnetic path member 72. In addition, the variable permanent magnet 78 is magnetized again by the magnetic flux Φ _E generated by passing a current through the coil 76, and a magnetic flux Φ _M1 is generated by the variable permanent magnet 78. If the second magnetic path member 74 is attracted and the magnetic flux Φ _M1 is generated by the variable permanent magnet 78, the magnetic flux Φ _M1 of the variable permanent magnet 78 is maintained even if the magnetic flux Φ _E by the coil 76 is eliminated. Therefore, the variable permanent magnet 78 does not cause self-demagnetization, the magnetic force is maintained, and the attracted state is maintained.

  The bypass magnetic path member 84 may be fixed, and the second magnetic path member 74 may move while being in contact with the fixed bypass magnetic path member 84.

  Each of the above embodiments is an exemplification, and various modifications are possible within the scope of the gist of the present invention. For example, the shapes of the first magnetic path member, the second magnetic path member, the detour magnetic path member, and the permanent magnet can be changed.

  DESCRIPTION OF SYMBOLS 10 Actuator, 12 1st magnetic path member, 14 2nd magnetic path member, 14A 1st magnetic path piece, 14B 2nd magnetic path piece, 16 coils, 18 Variable permanent magnet (1st permanent magnet), 22 Back extension part, 24 detour magnetic path member, 26 release spring, 30 actuator, 32 first magnetic path member, 34 second magnetic path member, 34A first magnetic path piece, 34B second magnetic path piece, 36 coil, 38 variable permanent magnet (first 1 permanent magnet), 40 fixed permanent magnet (second permanent magnet), 42 rearward extension, 44 bypass magnetic path member, 46 release spring, 50 actuator, 52 first magnetic path member, 54 second magnetic path member, 56 coil , 58 variable permanent magnet (first permanent magnet), 64 bypass magnetic path member, 66 release spring, 70 actuator, 72 first magnetic path member, 74 second magnetic path member, 74A first magnetic path piece, 74B first Magnetic path pieces, 76 coils, 78 variable permanent magnet (first permanent magnet) 80 fixed permanent magnet (second permanent magnet) 84 bypass magnetic path member 86 releases the spring.

Claims (8)

A first magnetic path member;
A second magnetic path member that can be attracted to and released from the first magnetic path member;
A first permanent magnet that attracts the second magnetic path member to the first magnetic path member by a magnetic force;
A coil that generates magnetic flux in a magnetic circuit including a first magnetic path member, a second magnetic path member, and a first permanent magnet;
A release spring that urges the second magnetic path member in a direction to release from the first magnetic path member;
In a state where the second magnetic path member is released from the first magnetic path member, the second magnetic path member is attracted to the first magnetic path member so as to form a magnetic path parallel to the first permanent magnet. A detour magnetic path member arranged so as not to form a magnetic path parallel to the first permanent magnet in the state;
Have
The first permanent magnet has an irreversibly reduced magnetic flux density when the second magnetic path member is released compared to when it is attracted,
In a state where the second magnetic path member is released from the first magnetic path member, the magnetic flux generated by the coil bypasses the first permanent magnet and passes through the detour magnetic path member.
Actuator. The actuator according to claim 1,
The first permanent magnet is disposed in the second magnetic path member so as to move together with the second magnetic path member,
The detour magnetic path member is fixedly arranged,
Actuator. The actuator according to claim 1, further comprising a second permanent magnet included in a magnetic circuit including the first magnetic path member, the second magnetic path member, and the first permanent magnet,
In a state where the second magnetic path member is attracted to the first magnetic path member, the first permanent magnet and the second permanent magnet are in a parallel state, and the second magnetic path member is attracted to the first magnetic path member by a magnetic force. ,
When the second magnetic path member is released from the first magnetic path member, the polarity of the first permanent magnet is reversed by the magnetic flux of the second permanent magnet, and the first permanent magnet and the second permanent magnet are in series. Magnetic force does not act on the second magnetic path member,
Actuator.   4. The actuator according to claim 1, wherein the first permanent magnet irreversibly decreases the magnetic flux density by releasing the second magnetic path member from the first magnetic path member. Actuator. A first magnetic path member;
A second magnetic path member that can be attracted to and released from the first magnetic path member;
A first permanent magnet that attracts the second magnetic path member to the first magnetic path member by a magnetic force;
In a state where the second magnetic path member is released from the first magnetic path member, the second magnetic path member is attracted to the first magnetic path member so as to form a magnetic path parallel to the first permanent magnet. A detour magnetic path member arranged so as not to form a magnetic path parallel to the first permanent magnet in the state;
A magnetic circuit comprising:
The first permanent magnet has an irreversibly reduced magnetic flux density when the second magnetic path member is released compared to when it is attracted,
In a state where the second magnetic path member is released from the first magnetic path member, the magnetic flux generated in the magnetic circuit bypasses the first permanent magnet and passes through the detour magnetic path member.
Magnetic circuit. The magnetic circuit according to claim 5,
The first permanent magnet is disposed in the second magnetic path member so as to move together with the second magnetic path member,
The detour magnetic path member is fixedly arranged,
Magnetic circuit. The magnetic circuit according to claim 5, further comprising a second permanent magnet included in the magnetic circuit including the first magnetic path member, the second magnetic path member, and the first permanent magnet,
In a state where the second magnetic path member is attracted to the first magnetic path member, the first permanent magnet and the second permanent magnet are in a parallel state, and the second magnetic path member is attracted to the first magnetic path member by a magnetic force,
When the second magnetic path member is released from the first magnetic path member, the polarity of the first permanent magnet is reversed by the magnetic flux of the second permanent magnet, and the first permanent magnet and the second permanent magnet are in series. Magnetic force does not act on the second magnetic path member,
Magnetic circuit.   8. The magnetic circuit according to claim 5, wherein the first permanent magnet has an irreversible decrease in magnetic flux density due to the second magnetic path member being released from the first magnetic path member. , Magnetic circuit.

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