JP5467436B2 - Linear actuator - Google Patents

Description

  The present invention relates to a linear actuator.

  For example, Patent Document 1 discloses a suspension device that uses thrust and damping force generated by a single-phase linear motor (single-phase linear actuator).

JP 2008-286362 A

In the above prior art, since thrust is obtained only by the opposing coil and magnet, there is a problem that the degree of freedom in setting the change in thrust depending on the position is low.
Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to improve the degree of freedom in setting the change in thrust depending on the position.

In order to solve the above-mentioned problems, a linear actuator according to the present invention is arranged linearly in the arrangement direction of the coil, facing a first member having a plurality of coils arranged linearly and the coil. And a second member that moves relative to the first member in the arrangement direction of the plurality of coils , wherein the magnetic member is opposed to the coil. A counter member facing the surface opposite to the surface is provided on the first member, and the counter member has a magnetic flux density arranged at a position facing a center position in the moving direction of each of the plurality of coils. A plurality of high magnetic flux density portions that are likely to be high are provided linearly in the arrangement direction of the coil, and the magnetic flux density is less likely to be higher than the high magnetic flux density portion between each of the plurality of high magnetic flux density portions. Characterize

  According to the present invention, the degree of freedom in setting the characteristics of the linear actuator can be improved.

It is a figure which shows the longitudinal cross-section of the linear actuator which concerns on 1st Embodiment. It is sectional drawing which expands and shows the principal part of the linear actuator of 2 pole 2 slot shown by FIG. (A) is a magnetic flux diagram when the coil at the stroke center of the conventional linear actuator is not energized, and (B) is a state in which the mover is moved to the left in the figure with respect to the armature. It is a magnetic flux diagram in the case. (A) is a magnetic flux diagram when not energizing the coil at the stroke center (reference position) of the linear actuator of the first embodiment, and (B) is a diagram showing the mover with respect to the armature in the state of (A). It is a magnetic flux diagram at the time of moving to the left side in FIG. It is a figure which shows the characteristic of the linear actuator of 1st Embodiment. It is sectional drawing which expands and shows the principal part of the modification of 1st Embodiment (state of a reference position). It is a figure which shows the longitudinal cross-section of the linear actuator which concerns on 2nd Embodiment (state of a reference position). It is a figure which shows the characteristic of the linear actuator of 2nd Embodiment. It is a figure which shows the characteristic of the linear actuator of 3rd Embodiment. It is a figure which shows the characteristic of the linear actuator of 3rd Embodiment. It is sectional drawing which expands and shows the principal part of the linear actuator of 4th Embodiment (state of a reference position). (A) is a magnetic flux line diagram when not energizing the coil at the stroke center (reference position) of the linear actuator of the fourth embodiment, and (B) is a diagram showing the mover with respect to the armature in the state of (A). It is a magnetic flux diagram at the time of moving to the left side in FIG. It is a figure which shows the characteristic of the linear actuator of 4th Embodiment. It is a figure which shows the characteristic of the linear actuator of 4th Embodiment. It is sectional drawing which expands and shows the principal part of the modification of the linear actuator in FIG. 11 (state of a reference position). It is sectional drawing which expands and shows the principal part of the modification of the linear actuator in FIG. 15 (state of a reference position). 1 is a block diagram illustrating a schematic configuration of a suspension device for a railway vehicle that employs a linear actuator of the present invention. It is a top view of the trolley | bogie of a rail vehicle shown by FIG.

  In each embodiment described below, the object and problem described in the column of the problem to be solved by the above-described invention and the effect of the invention and the effect of the invention are not limited, and the problem and object described below are solved. Alternatively, the effects described below can be obtained.

[Stability of thrust characteristics]
In the following embodiments shown in FIGS. 1 to 14, for example, the thrust pulsation based on the relative displacement between the coil of the linear actuator and the permanent magnet (magnetic member) can be reduced as compared with the technique described in Patent Document 1 described above. Stable thrust characteristics can be obtained. This leads to an improvement in control accuracy for suppressing vibration.
In addition, the main built-in fixed core and auxiliary built-in fixed core made of magnetic material are placed on one side of the mover that is not opposite to the armature (inside the mover), reducing thrust pulsation and stabilizing thrust characteristics. Can be made.
Also, a plurality of auxiliary coils are arranged on one side of the mover that does not face the armature (inside the mover), the phase difference of the current between adjacent auxiliary coils is set to 180 degrees, and each auxiliary coil is Because it is arranged with a phase difference of about 90 degrees in electrical angle with respect to the armature coil, it is possible to generate damping force even at stroke positions where it was not possible to generate damping force conventionally. Thus, the stability at the time of failure of the linear actuator can be improved.
Furthermore, a large thrust pulsation can be reduced by arranging the auxiliary core between adjacent auxiliary coils.

[Increase in thrust and damping force of linear actuator]
In the following embodiments, a plurality of auxiliary coils are arranged on one side of the mover that does not face the armature (inside the mover), the phase difference of current between adjacent auxiliary coils is set to 180 degrees, Since the auxiliary coil is arranged with a phase difference of about 90 degrees in electrical angle with respect to the coil of the armature, the maximum value of the damping force can be increased as compared with the conventional linear actuator. The actuator can be reduced in size and increased in damping force.
Further, by arranging the coil and the auxiliary coil in the same phase, the thrust and damping force that can be generated by the coil and the thrust and damping force that can be generated by the auxiliary coil are in phase, so such a linear actuator. Then, the maximum thrust and the maximum damping force can be effectively improved.

[Simplification of configuration or improvement of productivity]
A linear actuator using a spring to reduce thrust pulsation is well known, but in the following embodiments, thrust pulsation can be reduced without using such a spring. As a result, when compared with the linear actuator of the well-known technique, the assembly can be easily performed, so that the productivity can be improved.
In the following embodiments, since the linear actuator is driven by a single-phase alternating current, the drive circuit can be simplified. In addition, the linear actuator can be simplified as compared with the three-phase linear motor, and the size can be reduced.

[Improved heat dissipation]
When a three-phase linear motor is used in a range where the operation stroke is small, only a specific phase (for example, U phase) may generate heat. Then, since the heat generating portion is localized, a problem of heat dissipation occurs. However, in the following embodiments, since a single-phase linear actuator is employed, all coils generate heat to the same extent regardless of the size of the operation stroke. Therefore, since the surface area of the heat generating portion is increased, heat dissipation is improved.

A railway vehicle 6 including a roll vibration damping device that is a suspension device in which a linear actuator according to the present invention is incorporated will be described with reference to FIGS. 17 and 18.
As shown in FIGS. 17 and 18, the railway vehicle 6 includes a vehicle body 2 and a carriage 4 to which the wheel shaft 3 is attached and attached to the vehicle body 2. The carriage 4 is rotatable about the vertical axis with respect to the vehicle body 2 and is connected so as to be relatively movable in a certain range in the vertical direction and the horizontal direction (vertical direction and horizontal direction in FIG. 17). The vehicle body 2 is supported via the air spring 5. A linear actuator 1 and a variable damping force damper 7 are connected between the vehicle body 2 and the carriage 4.

  The linear actuator 1 and the damping force variable damper 7 are respectively coupled between a center pin 8 fixed to the vehicle body 2 and support columns 9 and 10 fixed to the carriage 4. For this displacement, the thrust of the linear actuator 1 and the damping force of the damping force variable damper 7 act. The vehicle body 2 is provided with various sensor means 11 for detecting a vehicle state such as a stroke sensor for detecting a lateral displacement between the vehicle body 2 and the carriage 4 and an acceleration sensor for detecting a lateral acceleration of the vehicle body 2. A controller 12 for controlling the linear actuator 1 and the damping force variable damper 7 based on an input signal from the sensor means 11 is provided.

  The linear actuator 1 is an electromagnetic actuator that generates a thrust according to an energized current, and generates a thrust according to a drive signal from the controller 12. The damping force variable damper 7 has a damping force switching valve such as a solenoid valve, and is a hydraulic damper capable of switching the damping force in at least two stages by an energization current. The damping force is switched by a control signal from the controller 12. Although it is desirable to use the damping force variable damper 7 from the viewpoints of cost and performance, instead of this, a damper other than a damper whose damping force is not variable or a damper other than a hydraulic damper may be used, and the linear actuator 1 is used. Also good. The vibration reduction control logic of the vehicle body 2 can employ skyhook control, for example.

  The controller 12 controls the linear actuator 1 and the damping force variable damper 7 on the basis of the detection signal of the sensor means 11 to suppress the vibration of the vehicle body. For example, when the railway vehicle 6 travels at a low speed, so-called passive (no control) is performed, the linear actuator 1 is not operated, the damping force of the damping force variable damper 7 is switched to the high damping force side, and the damping force of the damping force variable damper 7 is changed. As a result, the vibration of the vehicle body 2 in the left-right direction is attenuated. On the other hand, when traveling at high speed, so-called active control is executed, the damping force of the damping force variable damper 7 is switched to the low damping force side, and the left and right vibrations of the cart 4 are caused to vibrate based on the lateral acceleration detected by the acceleration sensor. The thrust of the linear actuator 1 is controlled so as to absorb and suppress the vibration of the vehicle body 2 in the left-right direction. As a result, the left and right vibrations of the vehicle body 2 are suppressed in response to the input of disturbance to the carriage 4 due to an irregular track and the input of disturbance to the vehicle body 2 due to aerodynamic vibration, thereby improving ride comfort and running stability. Enables high-speed driving.

(First embodiment)
A first embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1, the linear actuator 1 includes a substantially bottomed cylindrical first member 13, and a second member 14 provided inside the first member 13 and relatively movable with respect to the first member 13. Have The first member 13 includes an armature 17. The armature 17 includes a plurality of (two in the first embodiment) coils 15A and 15B and a core formed of a cylindrical magnetic body (for example, a soft magnetic body such as iron). The core includes a center core 16A and end cores 16B and 16C arranged on both sides in the axial direction of the center core 16A. The second member 14 includes a mover 20 provided corresponding to the armature 17 of the first member 13. The mover 20 includes a plurality (two in the first embodiment) of the main permanent magnets 18A and 18B (magnetic member) and the axial movement direction (stroke direction) of the main permanent magnets 18A and 18B in FIG. Left and right) auxiliary permanent magnets 19A and 19B disposed on both sides. The auxiliary permanent magnets 19A and 19B are provided at positions that face the coils 15A and 15B when the linear actuator 1 makes a stroke, and do not face the coils when they are at a non-stroke center position (when they are at the reference position). This compensates for a decrease in thrust and damping force caused by the main permanent magnets 18A and 18B at the stroke end.

  The linear actuator 1 is configured by slidably inserting the second member 14 into the first member 13, and the bottom side (the right side in FIG. 1) of the second member 14 protrudes to the outside. At the end portions of the first member 13 and the second member 14, connecting portions 23 and 24 that are connected to the center pin 8 of the vehicle body 2 and the column 9 of the carriage 4 are provided. One end of a rod 25 (which constitutes a part of the opposing member) extending along the center line on the inside of the first member 13 is joined to the bottom of the first member 13. Armature bearings 26 and 27 for slidably guiding the outer peripheral surface of the mover 20 are provided on the inner peripheral portion of the armature 17 on the front end side (right side in FIG. 1) and the base end side (left side in FIG. 1). It is done.

  As shown in FIG. 1, the main permanent magnet 18A has an S pole on the outer peripheral side and an N pole on the inner peripheral side (in FIG. 1 and FIG. 2, a symbol S indicating that the outer peripheral side is the S pole is attached. The main permanent magnet 18B has an N pole on the outer peripheral side and an S pole on the inner peripheral side (in FIG. 1 and FIG. 2, the symbol N indicating that the outer peripheral side is the N pole is attached. ). The auxiliary permanent magnet 19A has an N pole on the outer peripheral side and an S pole on the inner peripheral side, and the auxiliary permanent magnet 19B has an S pole on the outer peripheral side and an N pole on the inner peripheral side. Two coils 15 </ b> A and 15 </ b> B wound in the circumferential direction are accommodated in the inner circumferential groove of the core 16. Each coil 15A, 15B has the axial center position coincident with each main permanent magnet 18A, 18B at the stroke center of the linear actuator 1 (stroke ± 0 mm (reference position) in the state shown in FIGS. 1 and 2). In this way, they are arranged opposite to each other.

  The coils 15A and 15B have a current phase difference of 180 degrees between them. Specifically, for example, the circuit configuration is such that the winding direction is the opposite direction, or the energization direction is opposite. As shown in FIG. 2, when the coils 15A and 15B are energized, a magnetic field is generated, and magnetic poles are generated in the center core 16A and the end cores 16B and 16C. As a result, an axial thrust is generated in the mover 20 by the attractive force and repulsive force between the magnetic poles generated in the central core 16A and the end cores 16B and 16C and the main permanent magnets 18A and 18B. Note that the magnetic pole pitch τp that is the axial distance between the centers of the two main permanent magnets 18A and 18B shown in FIG. 2 is the coil pitch τc that is the axial distance between the centers of the two coils 15A and 15B. Are set equal to each other. In addition, a certain clearance is provided between each core 16A, 16B, 16C and the mover 20.

  As shown in FIG. 1, the linear actuator 1 according to the first embodiment includes a main member of an opposing member disposed opposite to the main permanent magnets 18 </ b> A and 18 </ b> B at the stroke center of the linear actuator 1 inside the mover 20. Main built-in fixed cores 28A and 28B serving as high magnetic flux density portions and auxiliary built-in fixed cores 29A and 29B serving as auxiliary high magnetic flux density portions opposed to the auxiliary permanent magnets 19A and 19B. The main built-in fixed cores 28A and 28B and the auxiliary built-in fixed cores 29A and 29B are made of, for example, the same material as the core 16 and are coupled to the armature 17 via the rod 25. The core pitch (not shown) that is the axial distance between the centers of the main built-in fixed cores 28A and 28B and the auxiliary built-in fixed cores 29A and 29B is set equal to the magnetic pole pitch τp and the coil pitch τc. In addition, a certain clearance is provided between the main built-in fixed cores 28 </ b> A and 28 </ b> B and auxiliary built-in fixed cores 29 </ b> A and 29 </ b> B and the mover 20. Further, there is a space between each of the built-in fixed cores composed of the main built-in fixed cores 28A and 28B and the auxiliary built-in fixed cores 29A and 29B, and the magnetic flux density is less likely to be higher than each of the built-in fixed cores. The coil 15A and the main built-in fixed core 28A are paired, and the coil 15B and the main built-in fixed core 28B are paired.

The operation of the first embodiment will be described.
For comparison with the linear actuator 1 of the first embodiment, prior to describing the operation of the linear actuator 1 of the first embodiment, the armature 17 of the conventional linear actuator 1 ′ without the main built-in fixed cores 28 </ b> A and 28 </ b> B. The force acting between the movable element 20 and the movable element 20 will be described. In addition, the same name and code | symbol are provided to the structure which is the same as that of 1st Embodiment, or an equivalent. Further, description will be made using a simplified diagram in which the auxiliary permanent magnets 19A and 19B are not shown. FIG. 3A shows a magnetic flux diagram when the coils 15A and 15B are not energized at the stroke center of the conventional linear actuator 1 ′.

  At the stroke center, the magnetic flux exits from the N pole and enters the S pole via the end core 16B, the outer peripheral portion of the armature 17 and the end core 16C, and exits from the N pole and passes through the mover 20. Thus, a magnetic flux entering the south pole is generated. In this state, the attractive force or repulsive force acting between the armature 17 and the mover 20 is balanced. In this state, when the mover 20 moves to the left side in FIG. 3A with respect to the armature 17, the balance of the force between the armature 17 and the mover 20 is lost, and the linear actuator 1 'is shown in FIG. Transition to the state of (B). In this state, the axial center position of the center core 16A and the main permanent magnet 15A, the axial center position of the end core 16B and the auxiliary permanent magnet 19A (see FIG. 1), the end core 16C and the main permanent magnet 18B, The axial center positions of are consistent.

  Therefore, the linear actuator 1 ′ tries to maintain the state shown in FIG. In the state of FIG. 3 (B), magnetic flux that exits from the N pole and enters the S pole via the central core 16A, the outer peripheral portion of the armature 17 and the end core 16C, and the mover 20 exits from the N pole. And a magnetic flux entering the S pole via the. FIG. 5 shows the thrust pulsation between the armature 17 and the mover 20 when the state of FIG. 3 (A) is shifted to the state of FIG. 3 (B).

  When the coils 15A and 15B are energized in the state of FIG. 3A, there is a current phase difference of 180 degrees between the coils 15A and 15B. In addition, the end core 16B, the center core 16A, and the end core 16C are magnetized to the north, south, and north poles, respectively. Since the surface of the mover 20 is magnetized to the north and south poles by the main permanent magnets 18A and 18B, there is an attractive force between the cores 16A, 16B and 16C and the main permanent magnets 18A and 18B. Or a repulsive force acts and the thrust which moves the needle | mover 20 to the left side in FIG. 3 (A) generate | occur | produces. When the coils 15A and 15B are energized in the reverse direction, the direction of the generated magnetic flux is also reversed, so that the end core 16B, the center core 16A, and the end core 16C are respectively in the S pole, N pole, and S pole. Magnetized.

  In such a linear actuator 1 ', the thrust becomes maximum when the axial center positions of the coils 15A and 15B shown in FIG. 3A coincide with the axial center positions of the main permanent magnets 18A and 18B. For example, the thrust becomes zero when the axial center position of the center core 16A shown in FIG. 3B and the axial center position of the main permanent magnet 18A or 18B coincide. The coil generation force in FIG. 5 represents the thrust during this energization. Further, the thrust of the linear actuator 1 ′ is (thrust pulsation) + (coil generation force), which is the conventional thrust in FIG. 5.

  Next, FIG. 4A shows a magnetic flux diagram when the coils 15A and 15B are not energized at the stroke center of the linear actuator 1 of the first embodiment. Here, the auxiliary permanent magnets 19A and 19B and the auxiliary built-in fixed cores 29A and 29B will be described using a simplified diagram. In this state, the magnetic flux that exits from the N pole and enters the S pole via the end core 16B, the outer peripheral portion of the armature 17 and the end core 16C, and the mover 20, the main built-in fixed A magnetic flux entering the south pole via the core 28A, the rod 25, the main built-in fixed core 28B, and the mover 20 is generated. Thus, in a state where the coils 15A and 15B are not energized, the force generated between the center core 16A and the main permanent magnets 18A and 18B and between the end cores 16B and 16C and the main permanent magnets 18A and 18B, Two systems of forces (attraction or repulsion) are generated between the built-in fixed cores 28A and 28B and the main permanent magnets 18A and 18B.

  In this state, the attractive force or repulsive force acting between the armature 17 and the mover 20 is balanced. In this state, when the mover 20 moves to the left side in FIG. 4A with respect to the armature 17, the balance of force between the armature 17 and the mover 20 is lost, and the linear actuator 1 is shown in FIG. Try to shift to the state of B). The force generated between the mover 20 and the main built-in fixed cores 28A, 28B at this time is first between the main permanent magnets 18A, 18B and the main built-in fixed cores 28A, 28B in the state of FIG. Since the mutual axial center positions coincide with each other, a force for maintaining the mutual position acts between the mover 20 and the main built-in fixed cores 28A and 28B.

  That is, as shown in FIG. 5, the force generated between the armature 17 and the mover 20 (conventional method in FIG. 5) and the mover 20 and the main built-in fixed cores 28A and 28B are generated. It can be seen that there is a phase difference of 180 degrees from the force (the present invention in FIG. 5). Therefore, the thrust pulsation (the combined thrust pulsation in FIG. 5) when the coils 15A and 15B in the first embodiment are not energized is (the thrust pulsation between the armature 17 and the mover 20) + (movable element 20—main built-in fixed). The thrust pulsation between the cores 28A and 28B), and it can be seen that the linear actuator 1 of the first embodiment can reduce the thrust pulsation as compared with the conventional method.

  Here, when the coils 15A and 15B are energized in the state of FIG. 4A, there is a current phase difference of 180 degrees between the coils 15A and 15B, and therefore, for example, the end core 16B, The center core 16A and the end core 16C are magnetized to the north, south, and north poles, respectively. Since the surface of the mover 20 is magnetized to the north and south poles by the main permanent magnets 18A and 18B, there is an attractive force between the cores 16A, 16B and 16C and the main permanent magnets 18A and 18B. Or a repulsive force acts and the thrust which moves the needle | mover 20 to the left side in FIG. 4 (A) generate | occur | produces. When the coils 15A and 15B are energized in the reverse direction, the direction of the generated magnetic flux is also reversed, so that the end core 16B, the center core 16A, and the end core 16C are respectively in the S pole, N pole, and S pole. Magnetized.

  In such a linear actuator 1, the axial center positions of the coils 15A and 15B and the axial center positions of the main permanent magnets 18A and 18B shown in FIG. The thrust is maximized in the matched state. For example, the thrust is zero when the axial center position of the central core 16A shown in FIG. 4B and the axial center position of the main permanent magnet 18A or 18B are matched. . The coil generation force in FIG. 5 represents the thrust during this energization. Since the thrust of the linear actuator 1 (combined thrust in FIG. 5) is (synthetic thrust pulsation) + (coil generation force), as shown in FIG. 5, the combined thrust is a coil compared with the conventional thrust. The linear actuator 1 according to the first embodiment can be reduced in thrust pulsation as compared with the conventional method.

  In the first embodiment, the thrust of the linear actuator 1 when current is supplied to the coils 15 </ b> A and 15 </ b> B from the outside has been described, but this explanation applies the force from the outside to move the mover 20 to the armature 17. The present invention can also be applied to the case where a voltage is induced when moved by the movement. In this case, what is generated in the linear actuator 1 is not a thrust but a damping force. Further, the main built-in fixed cores 28A and 28B and the auxiliary built-in fixed cores 29A and 29B can have any shape. For example, as shown in FIG. 6, the linear actuator 1 can be configured by securing the axial width of the portion of the main built-in fixed cores 28 </ b> A and 28 </ b> B near the mover 20 and reducing the width of the other portions. . Thereby, the 1st member 13 (refer FIG. 1) of the linear actuator 1 can be reduced in weight.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to the accompanying drawings. In addition, the same name and code | symbol are provided to the structure which is the same as that of 1st Embodiment mentioned above, or equivalent. In addition, for the sake of brevity, descriptions overlapping with the first embodiment are omitted.
In the first embodiment, as shown in FIG. 5, the axial center position of the center core 16A and the axial center position of the main permanent magnet 18A or 18B (magnetic member) coincide, that is, the stroke is ± 40 mm. Sometimes the thrust and damping force of the linear actuator 1 become zero. Therefore, in the second embodiment, as shown in FIG. 7, a plurality (three in the second embodiment) of the mover 20 on the side not facing the armature 17, that is, inside the mover 20. Auxiliary coils 22A, 22B, and 22C (configured between the high magnetic flux density portions of the opposing member) were arranged to configure the linear actuator 21.

In the linear actuator 21, the phase difference of current between adjacent auxiliary coils 22A and 22B and between 22A and 22C is set to 180 degrees. Specifically, for example, the circuit configuration is such that the winding direction is the opposite direction, or the energization direction is opposite. The auxiliary coils 22 </ b> A, 22 </ b> B, and 22 </ b> C are coupled to the armature 17 through the rod 25. The auxiliary coils 22A, 22B, 22C are arranged with a phase difference of about 90 degrees in electrical angle with respect to the coils 15A, 15B of the armature 17. The axial center position distance τ _S2 between adjacent auxiliary coils 22A and 22B and between 22A and 22C is set substantially equal to the axial center position distance τ _S1 between the coils 15A and 15B. The auxiliary coils 22A, 22B, and 22C are made of a non-magnetic material (copper in this embodiment), and thus are magnetically equivalent to air.

  Here, the damping force when the auxiliary coils 22A, 22B, and 22C are short-circuited and the mover 20 is moved relative to the armature 17 by applying a force from the outside will be described. In the state of FIG. 7, since the axial center positions of the main permanent magnets 18A and 18B coincide with the boundary positions between the adjacent auxiliary coils 22A, 22B, and 22C, no damping force is generated. In this state, when the linear actuator 21 contracts, that is, when the mover 20 moves to the left in FIG. 7 with respect to the armature 17, a damping force is generated between the mover 20 and the auxiliary coils 22A, 22B, and 22C. The combined damping force generated by the linear actuator 21 at this time is (thrust pulsation between the armature 17 and the mover 20) + (coil generation damping force) + (auxiliary coil generation damping force). The present invention is represented by the damping force.

Therefore, in the second embodiment, it is possible to generate a damping force even at a stroke position (a position of ± 40 mm in FIG. 8) where the damping force cannot be generated by the conventional method. Stability at the time of failure can be improved. Further, as can be seen from FIG. 8, the maximum value of the damping force is increased as compared with the conventional linear actuator 1 ′, and the linear actuator 21 can be reduced in size and increased in damping force. Furthermore, in 2nd Embodiment, since auxiliary coil 22A, 22B, 22C is always a short circuit state, even if it is a case where coil 15A, 15B is a disconnection, a dielectric breakdown, etc., the needle | mover 20 and auxiliary coil 22A, By generating a damping force between 22B and 22C, the stability at the time of failure can be improved.
In the present embodiment, the high magnetic flux density portion of the present invention has the auxiliary coils 22A, 22B, and 22C that are likely to have a high magnetic flux density only when the mover 20 is moved relative to the armature 17. The magnetic flux density is unlikely to be high at the axially intermediate portions of the auxiliary coils 22A, 22B, and 22C.

(Third embodiment)
A third embodiment of the present invention will be described with reference to the accompanying drawings. In addition, the same name and code | symbol are provided to the structure which is the same as that of 1st and 2nd embodiment mentioned above, or equivalent. Further, for the sake of brevity, the description overlapping with the first and second embodiments is omitted.
In the second embodiment, the auxiliary coils 22A, 22B, and 22C (opposing members) are always short-circuited with emphasis on countermeasures against failure, but in the third embodiment, the auxiliary coils 22A, 22B, and 22C are externally connected. Emphasis is placed on improving the vibration damping performance by supplying current from In order to embody this, in the third embodiment, a stroke sensor (not shown) for detecting the stroke position is provided, and the energization directions of the auxiliary coils 22A, 22B, and 22C are based on the stroke position detected by the stroke sensor. The linear actuator 21 was configured to control the above.

  The linear actuator 21 having an N pole N slot structure (N is an integer of 2 or more) as shown in FIG. 7 can be driven without using a stroke sensor. In this case, the direction of the control force, that is, The direction of thrust generated by energization of the auxiliary coils 22A, 22B, and 22C depends on the direction of current. FIG. 9 shows the thrust generated when the auxiliary coils 22A, 22B, and 22C are energized (auxiliary coil generated thrust). As shown in this figure, the thrust generated when the auxiliary coils 22A, 22B, and 22C are energized contracts with the extension force (the thrust ratio in FIG. 9 is the + side) with reference to the stroke center (position of the stroke 0 mm). 9 (the thrust ratio in FIG. 9 is -side), and the resultant thrust in this case is (thrust pulsation) + (coil generation force) + (auxiliary coil generation force).

  Accordingly, in the contraction direction of the stroke based on the stroke of 0 mm, it is possible to generate a larger thrust than that of the conventional linear actuator 1 ′, but in the extension direction of the stroke based on the stroke of 0 mm, the conventional linear actuator Only a thrust smaller than 1 'can be generated. Therefore, in the third embodiment, as described above, the stroke sensor for detecting the stroke position is disposed, and the linear actuator 21 is controlled so as to control the energization direction of the auxiliary coils 22A, 22B, and 22C based on the detected stroke position. Configured. In this case, the stroke position for switching the energization direction is preferably the center of the stroke.

  In the third embodiment, a position sensor such as a high-precision potentiometer or laser displacement meter is used to detect the stroke position, and the current supplied to the auxiliary coils 22A, 22B, and 22C depends on the stroke position and the thrust command. Thus, by appropriately controlling, it is possible to generate a composite thrust represented by the same curve as the composite damping force (the present invention damping force) as shown in FIG. However, the linear actuator 21 is required to reduce costs and not use a stroke sensor. In this case, it is desirable to use a relatively low-cost position sensor such as a Hall element as the stroke sensor.

  When the Hall element is used as a stroke sensor, the sensor output changes depending on the sensor mounting state, the energization of the auxiliary coils 22A, 22B, and 22C, and thus it is difficult to detect the position with high accuracy. Therefore, as shown in FIG. 10, the current supplied to the auxiliary coils 22A, 22B, and 22C in the other regions should not be energized within the region of ± 15 mm from the stroke center, for example. The linear actuator 21 can be configured to switch the direction of the.

  In the third embodiment, it is not necessary to use a high-accuracy position sensor for detecting the stroke position. For example, a relatively low-cost position sensor such as a Hall element can be used. Can be suppressed. In addition, since the current is supplied to the auxiliary coils 22A, 22B, and 22C only in the stroke region where the thrust can be generated with high efficiency, the coils 15A and 15B and the auxiliary coils 22A, 22B, and 22C are made efficient. By utilizing it effectively, a larger thrust can be generated, and the linear actuator 21 can be miniaturized and the damping performance can be improved.

  Furthermore, in the third embodiment, for example, the coils 15A and 15B are energized to generate thrust, thereby regenerating and using the currents induced in the auxiliary coils 22A, 22B and 22C, thereby achieving high vibration suppression with less power. Performance can be obtained. In the third embodiment, the ratio of the current supplied to the coils 15A, 15B and the auxiliary coils 22A, 22B, 22C can be arbitrarily set. For example, in the vicinity of the stroke center where a large thrust can be generated efficiently, the current supplied to the coils 15A and 15B is increased, and the stroke generated by the auxiliary coils 22A, 22B and 22C is about ± 40 mm (see FIG. 10), the current supplied to the auxiliary coils 22A, 22B, and 22C is increased.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to the accompanying drawings. In addition, the same name and code | symbol are provided to the structure same as the 1st-3rd embodiment mentioned above or an equivalent. In addition, for the sake of brevity, descriptions overlapping with the first to third embodiments are omitted.
In the second and third embodiments described above, as shown in FIG. 7, a plurality of (second and third embodiments) are provided on the side of the mover 20 that does not face the armature 17, that is, on the inner side of the mover 20. Then, by arranging the three) auxiliary coils 22A, 22B, and 22C (opposing members) to constitute the linear actuator 21, the stroke region in which thrust and damping force are generated and the force are improved.

  As shown in FIG. 11, in the fourth embodiment, auxiliary cores 32A and 32B that are high magnetic flux density portions of the present invention are arranged between adjacent auxiliary coils 22A, 22B, and 22C in the second and third embodiments. Thus, the linear actuator 31 is configured to reduce a large thrust pulsation. The auxiliary cores 32A and 32B are coupled to the armature 17 via the rod 25 (see FIGS. 1 and 7). FIG. 12A shows a magnetic flux diagram when the coils 15A and 15B and the auxiliary coils 22A, 22B, and 22C are not energized. Here, the auxiliary permanent magnets 19 </ b> A and 19 </ b> B will be described using a simplified diagram in which illustration is omitted.

  When FIG. 12A is used as the stroke center of the linear actuator 31, the magnetic flux exits the N pole and enters the S pole via the end core 16B, the outer peripheral portion of the armature 17, and the end core 16C. Then, a magnetic flux that exits from the N pole and enters the S pole via the mover 20, the auxiliary core 32A, the rod 25, the auxiliary core 32B, and the mover 20 is generated. As a result, in a state where the coils 15A, 15B and the auxiliary coils 22A, 22B, 22C are not energized, between the center core 16A and the main permanent magnets 18A, 18B (magnetic member) and the end cores 16B, 16C and the main permanent magnet 18A. , 18B, and a force generated between the auxiliary cores 32A, 32B and the main permanent magnets 18A, 18B (two attractive forces or repulsive forces) are generated.

  In the state of FIG. 12A, the attractive force or repulsive force acting between the armature 17 and the mover 20 is balanced. In this state, when the mover 20 moves to the left side in FIG. 12A with respect to the armature 17, the balance of the force between the armature 17 and the mover 20 is lost, and the linear actuator 31 is shown in FIG. Try to shift to the state of B). At this time, the force generated between the mover 20 and the auxiliary cores 32A and 32B is, first, in the state of FIG. 12A, the axial directions of the main permanent magnets 18A and 18B and the auxiliary cores 32A and 32B. Since the center positions coincide with each other, a force for maintaining the mutual position acts between the mover 20 and the auxiliary cores 32A and 32B.

  That is, as shown in FIG. 13, the force (thrust pulsation) generated between the armature 17 and the mover 20 and the force (thrust pulsation) generated between the mover 20 and the auxiliary cores 32A and 32B. Indicates that there is a phase difference of 180 degrees. Therefore, the thrust pulsation (the thrust pulsation between the mover and the auxiliary core in FIG. 13) when the coils 15A and 15B and the auxiliary coils 22A, 22B, and 22C are not energized in the fourth embodiment is (between the armature 17 and the mover 20). (Thrust pulsation)) + (thrust pulsation between the mover 20 and the auxiliary cores 32A and 32B), it can be seen that the thrust pulsation is reduced in the linear actuator 31 of the fourth embodiment compared to the conventional method.

  Here, the damping force when the coils 15A, 15B and the auxiliary coils 22A, 22B, 22C are short-circuited and the mover 20 is moved relative to the armature 17 by applying a force from the outside will be described. In the state of FIG. 11, since the axial center positions of the main permanent magnets 18A and 18B and the axial center positions of the auxiliary cores 32A and 32B coincide with each other, no damping force is generated. In this state, when the linear actuator 31 contracts, that is, when the mover 20 moves to the left side in FIG. 11 with respect to the armature 17, a damping force is generated between the mover 20 and the auxiliary cores 32A and 32B. The combined damping force generated by the linear actuator 31 at this time is (thrust pulsation between the armature 17 and the mover 20) + (coil generated damping force) + (auxiliary core generated damping force). It is expressed by damping force.

  Therefore, in the fourth embodiment, it is possible to generate the damping force even at the stroke position (position of ± 40 mm in FIG. 13) where the damping force could not be generated by the conventional method, and the linear actuator 31. It is possible to improve the stability at the time of failure. In the fourth embodiment, since the coils 15A and 15B and the auxiliary coils 22A, 22B, and 22C are always short-circuited, if the coils 15A and 15B and the auxiliary coils 22A, 22B, and 22C are disconnected, broken down, etc. Even so, the occurrence of a damping force between the mover 20 and the auxiliary cores 32A and 32B can improve the stability at the time of failure.

  Further, in the fourth embodiment, by arranging the auxiliary cores 32A, 32B between the adjacent auxiliary coils 22A, 22B, 22C, as shown in FIG. 13, thrust pulsation (between the mover and the auxiliary core in FIG. 13). Since the thrust pulsation is reduced, the linear actuator 31 can be easily handled. Specifically, the initial position of the conventional linear actuator 1 ′ is a position where the axial center position of the central core 16A coincides with the boundary position between the main permanent magnets 18A and 18B. When 'is attached to an object such as a vehicle, it is necessary to extend or contract the linear actuator 1 ′. However, in the fourth embodiment, the thrust pulsation is reduced to facilitate the attachment work. it can.

  Next, in the fourth embodiment, a case where the coils 15A and 15B and the auxiliary coils 22A, 22B, and 22C are energized will be described. As described in the third embodiment, the thrust generated when the auxiliary coils 22A, 22B, and 22C are energized is based on the stroke center (position of the stroke 0 mm) (the thrust ratio in FIG. 9 is the + side). And the contraction force (thrust ratio in FIG. 9 is -side), but using a highly accurate stroke sensor (position sensor), the coils 15A and 15B and the auxiliary are used according to the stroke position and the direction of thrust. By appropriately supplying current to the coils 22A, 22B, and 22C, it is possible to generate a composite thrust that draws the same curve with respect to the composite damping force as shown in FIG. FIG. 14 shows thrust characteristics of the linear actuator 31 of the fourth embodiment when an operation equivalent to that of the third embodiment is performed using a simple stroke sensor (position sensor) such as a Hall element. .

  In the fourth embodiment, in the stroke center where the thrust generated with respect to the supplied current is small (low efficiency), the auxiliary coils 22A, 22B and 22C are not energized, and the stroke region where relatively high efficiency is obtained. While energizing the diaphragm and auxiliary coils 22A, 22B, and 22C, the stroke position near the center of the stroke is detected with high accuracy by a stroke sensor (position sensor), and the auxiliary coils 22A, 22B, and 22C are detected based on the detection result of the stroke sensor. It was configured to switch the direction of the supplied current. Therefore, in the fourth embodiment, by using the coils 15A and 15B and the auxiliary coils 22A, 22B, and 22C efficiently and effectively, a large thrust can be generated, and the linear actuator 31 can be downsized. It is possible to improve vibration control performance.

  Further, in the fourth embodiment, a relatively low-cost position sensor such as a Hall element can be employed. For example, it is manufactured in comparison with the case where a highly accurate position sensor such as a potentiometer or a laser displacement meter is used. Cost can be reduced. Further, by generating thrust by the coils 15A and 15B and regenerating and using the current induced by the auxiliary coils 22A, 22B, and 22C, high vibration damping performance can be obtained with less power. The ratio of the current supplied to the coils 15A, 15B and the auxiliary coils 22A, 22B, 22C can be arbitrarily set. For example, in the vicinity of the stroke center where a large thrust can be generated efficiently, the current supplied to the coils 15A and 15B is increased, and the stroke generated by the auxiliary coils 22A, 22B and 22C is about ± 40 mm (see FIG. 13), the current supplied to the auxiliary coils 22A, 22B, and 22C can be increased.

In the second to fourth embodiments, the axial center position distance τ _S1 between the coils 15A and 15B is equal to the axial center position distance τ _S2 between the adjacent auxiliary coils 22A, 22B, and 22C. Although configured, it is not intended to be limited to this. By setting τ _S1 ≠ τ _S2 and arbitrarily setting the characteristics of the thrust and damping force that can be generated by the auxiliary coils 22A, 22B, and 22C, it becomes possible to design the linear actuators 21 and 31 according to their use. Further, the phase difference between the coils 15A and 15B and the auxiliary coils 22A, 22B and 22C can be set arbitrarily. For example, as shown in FIG. 15, the linear actuator 34 can be configured by arranging the coils 15A and 15B and the auxiliary coils 22A and 22B in the same phase.

  In this case, the thrust and damping force that can be generated by the coils 15A and 15B and the thrust and damping force that can be generated by the auxiliary coils 22A and 22B have the same phase. Therefore, in such a linear actuator 34, thrust is generated. Although the stroke range is the same as that of the above-described embodiment, the maximum thrust and the maximum damping force can be effectively improved. Thereby, the linear actuator 34 can be reduced in size by limiting a stroke. In the third and fourth embodiments, the coils 15A and 15B and the auxiliary coils 22A, 22B, and 22C can arbitrarily select the energization mode, the regeneration mode, and the short-circuit mode as necessary.

As a modification of the linear actuator 34 in FIG. 15, as shown in FIG. 16, an auxiliary core 32 can be provided between the auxiliary coils 22 </ b> A and 22 </ b> B to configure the linear actuator 35. In this case, thrust pulsation is generated between the auxiliary core 32 and the main permanent magnets 18A and 18B, and the thrust pulsation is larger than that of the conventional linear actuator 1 ', but compared with the linear actuator 34 shown in FIG. Thus, a larger thrust can be obtained, and the linear actuator 35 can be reduced in size.
Moreover, in the said embodiment, although the pitch of the high-density magnetic flux part arrange | positioned inside a magnetic member is made the same with the pitch of a coil, the characteristic of the thrust and damping force as a whole is changed by comprising differently. be able to.
Furthermore, in the above-described embodiment, the axial position of the high-density magnetic flux portion is the same as the position of the coil, but the overall thrust and damping force characteristics can be changed by configuring differently.
Moreover, although the cylindrical linear motor was demonstrated to the example in the said embodiment, it is good also considering a 1st member, a 2nd member, and an opposing member as a flat plate.
Furthermore, in the above-described embodiment, an example in which the present invention is used for a railway has been shown. However, the present invention is not limited to this, and the present invention can also be used for an automobile suspension or a building vibration damper.

1, 21, 31, 34, 35 Linear actuator, 15A, 15B Coil, 17 Armature, 18A, 18B Main permanent magnet (magnetic member), 20 Mover, 22A, 22B, 22C Auxiliary coil (opposing member), 28A, 28B Main built-in fixed core (opposing member)

Claims (5)

A first member having a plurality of coils arranged in a straight line;
A second member having a plurality of magnetic members arranged linearly in the arrangement direction of the coils facing the coil and relatively moving in the arrangement direction of the plurality of coils with respect to the first member A linear actuator consisting of
The first member is provided with a facing member facing the surface opposite to the facing surface of the coil of the magnetic member,
The opposing member has a plurality of high magnetic flux density portions, which are likely to be high in magnetic flux density , arranged linearly in the arrangement direction of the coils. Provided,
Wherein the plurality of each of between the high magnetic flux density section linear actuator, characterized in that it is the magnetic flux density is hardly higher than the high magnetic flux density section.   The linear actuator according to claim 1, wherein the high magnetic flux density portion of the facing member is made of a magnetic material.   The linear actuator according to claim 1, wherein an auxiliary coil is provided on the opposing member, and the high magnetic flux density portion is formed by a gap between the auxiliary coils.   The linear actuator according to claim 1, wherein a pitch of the high magnetic flux density portion of the facing member is the same as a pitch between the coils.   The position of the axially intermediate portion of the high magnetic flux density portion of the opposing member is attached so that the position where the axial position of the coil and the axially intermediate portion is the same is the reference position. 4. The linear actuator according to any one of 4.

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