JP4534219B2 - Linear electromagnetic actuator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a linear electromagnetic actuator capable of linearly displacing a moving body under the drive action of a linear DC motor that functions as a drive source.
[0002]
[Prior art]
Conventionally, a linear direct current motor (LDM) is known as one of linear motors, and this linear direct current motor has features such as a simple structure, high-speed response, and simplicity of a control method.
[0003]
The linear DC motor is roughly classified into a single-pole linear DC motor using a permanent magnet as a field magnet and a multi-pole linear DC motor using a plurality of permanent magnets in which magnetic poles are alternately arranged in parallel. .
[0004]
[Problems to be solved by the invention]
However, the linear DC motor according to the related art has a problem that the outer diameter is increased when a long stroke is to be obtained. That is, in the linear DC motor according to the prior art, the thickness of the yoke (magnetic material such as low carbon steel) is sufficiently set so that magnetic flux is generated in the yoke along the thrust generation direction and the magnetic flux is not saturated. There is a need to. For this reason, as the stroke is increased, the dimension in the thickness direction of the yoke is increased to become a heavy object, and there is a problem that the outer diameter dimension of the entire apparatus is increased and the size is increased.
[0005]
In addition, when a multipole linear DC motor is used, it is possible to obtain a long stroke, but in order to continuously move a long distance along one direction, the current that flows through the coil every time the magnetic pole changes Therefore, a control means such as switching the direction of the current or controlling the direction of the current flowing through the coil is required, resulting in a complicated structure. Furthermore, the magnitude of the thrust changes depending on the stroke length, and a thrust ripple (torque ripple) may occur.
[0006]
The present invention has been made in consideration of the above-mentioned problems, and provides a linear electromagnetic actuator capable of obtaining a long stroke with a simple structure without increasing the outer diameter of the entire apparatus. With the goal.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a linear electromagnetic actuator having a stator and a mover and displacing the mover by a thrust generated based on Fleming's left hand rule.
An outer yoke having a U-shaped cross section having a pair of side portions and a bottom portion which are made of a magnetic material and arranged to face each other at a predetermined interval;
A set of permanent magnets respectively fixed to a set of sides of the outer yoke;
A first plate disposed between the pair of permanent magnets via an air gap and formed with a first protrusion protruding toward one permanent magnet side, and protruding toward the other permanent magnet side An armature yoke coupled with a second plate on which a second protrusion is formed;
A first coil wound along the circumferential surface of the first plate and a second coil wound along the circumferential surface of the second plate are provided such that coil currents flow in opposite directions. A coil portion having a coil;
It is characterized by providing.
[0008]
In this case, it is preferable to provide a moving body that is displaced integrally with the mover, and further to provide a linear guide that guides the moving body along the axial direction of the outer yoke.
[0009]
Alternatively, the armature yoke may be formed by alternately connecting a plurality of first plates and second plates.
[0010]
Furthermore, a stator is constituted only by the outer yoke, the first permanent magnet interposed between the first plate and the first coil facing one side of the outer yoke, and the other side of the outer yoke. The second permanent magnet interposed between the second plate and the second coil is configured to be included in the mover, or the permanent magnet interposed between the first plate and the second plate. May be included in the mover.
[0011]
According to the present invention, a magnetic flux is generated between the outer yoke and the projection of the armature yoke by the permanent magnet. At that time, the magnetic flux introduced into the armature yoke from one side portion of the outer yoke is led toward the other side portion of the outer yoke after being bent at the joint portion between the first plate and the second plate, and further the magnetic flux Passes through the bottom of the outer yoke and returns to the original side. Therefore, the coil portion is energized, and the coil current flows along the opposite direction to each other. Based on Fleming's left-hand rule between the first coil and the second coil and the magnetic flux, one outer yoke side and the other Thrust in the same direction is generated on the outer yoke side. The mover is displaced based on this thrust.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the linear electromagnetic actuator according to the present invention will be described below and described in detail with reference to the accompanying drawings.
[0013]
In FIG. 1, reference numeral 10 indicates a linear electromagnetic actuator according to an embodiment of the present invention.
[0014]
The linear electromagnetic actuator 10 includes a flat base member 12 and an outer yoke 13 having a U-shaped cross section fixed on a plane of the base member 12 via a screw member (not shown). The outer yoke 13 is formed by integrally connecting a pair of side portions 14a and 14b erected substantially parallel to each other at a predetermined interval and a bottom portion 18 connecting the pair of side portions 14a and 14b. Composed. A pair of rail-shaped permanent magnets 16a and 16b are fixed to the inner surfaces of the side portions 14a and 14b so as to face each other.
[0015]
The outer yoke 13 is preferably formed of a magnetic material such as SS400 according to JIS standards, and the permanent magnets 16a and 16b are magnetized along the thickness direction thereof. The outer yoke 13 (the side portions 14a and 14b and the bottom portion 18) and the permanent magnets 16a and 16b function as a stator for the linear DC motor.
[0016]
As shown in FIG. 3, a substantially L-shaped support block 20 is connected to the base member 12 in the vicinity of one side portion 14 b of the outer yoke 13, and a long guide rail 22 is provided above the support block 20. Is connected to the side portion 14b of the outer yoke 13 substantially in parallel.
[0017]
As shown in FIG. 1, a moving body 24 is provided so as to extend in a direction substantially perpendicular to the axis of the pair of side portions 14a and 14b and the permanent magnets 16a and 16b of the outer yoke 13, and the moving body 24 Is along the axial direction (arrow X direction) of the side portions 14a and 14b of the outer yoke 13 and the permanent magnets 16a and 16b via a guide block 26 (see FIG. 3) having a U-shaped cross section that engages with the guide rail 22. It can be displaced freely.
[0018]
In other words, one end of the moving body 24 is supported via a linear guide 28 composed of a guide rail 22 and a guide block 26, and the movable body 24 is slidably displaced along the guide rail 22 integrally with the guide block 26. It is provided freely.
[0019]
As shown in FIGS. 2 and 3, a coil holder 30 is fixed to the lower surface portion of the moving body 24, and the coil holder 30 has a predetermined air gap 32a between a pair of permanent magnets 16a and 16b. 32b is provided so as to be separated from each other. Inside the coil holder 30, an armature yoke 34 around which a coil to be described later is wound is disposed.
[0020]
As shown in FIGS. 4 and 5, the armature yoke 34 includes a flat plate-like first plate 36 a and a second plate 36 b having substantially the same thickness, dimensions, etc., which are partially overlapped and integrated. The block body has a first protrusion portion (first protrusion portion) 38a protruding toward one permanent magnet 16a and the other permanent magnet 16b side. And a second protrusion (second protrusion) 38b.
[0021]
In other words, the cross-sectional shape of the armature yoke 34 along the substantially horizontal direction is formed in a right-angle cross-section between the first protrusion 38a and the second plate 36b, as shown in FIG. It has a step portion, and also has a step portion formed in a right-angle cross section between the second protrusion 38b and the first plate 36a.
[0022]
A first coil 40a is wound around the rectangular peripheral surface of the first plate 36a, and a first coil 40a is wound around the rectangular peripheral surface of the second plate 36b in a direction opposite to the first coil 40a. Two coils 40b are wound, and the first coil 40a and the second coil 40b constitute a coil portion 42. The armature yoke 34 and the coil portion 42 function as a mover for the linear DC motor.
[0023]
The support block 20 is provided with position detection means 46 including an encoder scale 44 for detecting the position of the moving body 24, and a detection signal detected by the position detection means 46 is output toward a controller (not shown). .
[0024]
As shown in FIG. 1 and FIG. 2, a pair of stoppers 48a for restricting the displacement of the coil holder 30 by contacting the coil holder 30 at both end sides along the axial direction with the coil holder 30 in between. 48b are opposed to each other.
[0025]
The linear electromagnetic actuator 10 according to the embodiment of the present invention is basically configured as described above. Next, the operation and action and effects thereof will be described.
[0026]
As shown in FIG. 5, a magnetic flux is generated from one permanent magnet 16b magnetized along the thickness direction, and this magnetic flux passes through the armature yoke 34 via the air gap 32b and further passes through the air gap 32a. Through the other permanent magnet 16a, one side portion 14a of the outer yoke 13, the bottom portion 18 and the other side portion 14b to return to the original permanent magnet 16b. When the magnetic flux passes through the armature yoke 34, as shown in FIG. 5, the magnetic flux that has traveled straight along the second protrusion 38b of the second plate 36b is coupled to the first plate 36a and the second plate 36b. Is bent toward the first plate 36a side, and further proceeds along the first protrusion 38a.
[0027]
When magnetic flux is generated in this way, by energizing a power source (not shown) and causing current to flow through the coil part 42, thrust in the direction of the arrow (Lorentz force) is generated based on Fleming's left-hand rule. Under the action of the thrust, the armature yoke 34, the coil part 42, and the moving body 24 are integrally displaced along the arrow X direction along the guide rail 22.
[0028]
That is, the magnetic flux led out from one permanent magnet 16b to the second ridge 38b of the armature yoke 34 through the air gap 32b, and the other from the first ridge 38a of the armature yoke 34 through the air gap 32a. The magnetic flux derived toward the permanent magnet 16a acts on the coil currents flowing through the first coil 40a and the second coil 40b, respectively, to generate thrust (Lorentz force). The direction of the generated thrust is Fleming The direction of the arrow is based on the left hand rule.
[0029]
Note that the coil current and the magnetic flux flowing in the first and second coils 40a and 40b, respectively, are in a direction substantially orthogonal to the arrow direction in which thrust is generated.
[0030]
When the armature yoke 34, the coil portion 42, and the moving body 24 are displaced along the direction of the arrow X under the action of the thrust, the position of the moving body 24 is detected by the position detecting means 46, and from the position detecting means 46 The derived detection signal is input to a controller (not shown). Further, when the coil holder 30 abuts against the stopper 48b, the displacement is restricted and the stroke end position is obtained.
[0031]
When the armature yoke 34, the coil part 42 and the moving body 24 are displaced in the direction opposite to the above, the direction of the coil current passed through the first and second coils 40a, 40b is reversed by the switching means (not shown). By switching, thrust is generated in the direction opposite to the arrow direction, and the moving body 24 is displaced along the direction opposite to the above.
[0032]
In the present embodiment, the magnetic flux flowing through the outer yoke 13 (side portions 14a and 14b and the bottom portion 18) and the permanent magnets 16a and 16b functioning as a stator of the linear DC motor is substantially perpendicular to the thrust generation direction. It is not necessary to increase the thickness of the outer yoke 13 (side portions 14a and 14b and the bottom portion 18) in order to sufficiently flow the magnetic flux, and a long stroke can be obtained. Therefore, since it is not necessary to change the cross-sectional shape of the outer yoke 13 even if the stroke becomes longer, the outer diameter of the entire apparatus is not increased, and a long stroke can be obtained with a simple structure.
[0033]
As a result, in this embodiment, it is possible to obtain a linear electromagnetic actuator 10 that is small and light and has a long stroke.
[0034]
In the linear electromagnetic actuator 50 according to the comparative example as shown in FIG. 6, the coil 54 is wound along the peripheral surface of the armature yoke 52 formed of a flat block body, and the magnetic flux is generated along the arrow A direction. appear. Therefore, in the linear electromagnetic actuator 50 according to the comparative example, the thrust F1 and the thrust F2 along the opposite directions are generated on one side and the other side of the coil 54 under the action of the current and the magnetic flux flowing through the coil 54. Since each occurs, the moving body (not shown) remains stationary without being displaced.
[0035]
In the present embodiment, the shape of the armature yoke 34 is not limited to the staircase shape as shown in FIGS. 4 and 5, but as shown in FIG. 7, the first and second plates 36a. The armature yoke 56 may be configured by connecting a plurality of block bodies formed in a staircase shape by joining together. In FIG. 7, reference numeral 58 indicates a coil holder.
[0036]
Further, as shown in FIGS. 8 and 9, the side portions 14a and 14b and the bottom portion 18 of the outer yoke 13 may be disposed as the stator of the linear DC motor, and the permanent magnet may be disposed on the mover side. Good.
[0037]
For example, in FIG. 8, the first permanent magnet 60a is provided adjacent to the first plate 36a so as to be close to one side portion 14a of the outer yoke 13, and the first permanent magnet 60a is set so as to be close to the other side portion 14b of the outer yoke 13. 9, two permanent magnets 60b are provided adjacent to the second plate 36b. In FIG. 9, the first plate 36a and the second plate 36b are interposed between the first plate 36a and the second plate 36b. The plate 36b is connected. By comprising in this way, the effect similar to the above is acquired.
[0038]
【The invention's effect】
According to the present invention, the following effects can be obtained.
[0039]
That is, since the magnetic flux generated by the permanent magnet is substantially perpendicular to the thrust generation direction, it is not necessary to increase the thickness of the outer yoke in order to sufficiently flow the magnetic flux, and a long stroke can be obtained. Accordingly, since it is not necessary to change the cross-sectional shape of the outer yoke even if the stroke becomes long, the outer diameter of the entire apparatus is not increased, and a long stroke can be obtained with a simple structure.
[Brief description of the drawings]
FIG. 1 is a plan view of a linear electromagnetic actuator according to an embodiment of the present invention.
2 is a longitudinal sectional view taken along line II-II in FIG.
3 is a longitudinal sectional view taken along line III-III in FIG.
4 is a partially omitted cross-sectional view of the stator and mover of the linear electromagnetic actuator shown in FIG. 1 along a substantially horizontal direction.
5 is a partially omitted perspective view showing the flow of magnetic flux of the linear electromagnetic actuator shown in FIG. 1. FIG.
FIG. 6 is a partially omitted cross-sectional view along a substantially horizontal direction of a stator and a mover of a linear electromagnetic actuator according to a comparative example.
FIG. 7 is a partially omitted cross-sectional view along a substantially horizontal direction showing a modification of the armature yoke.
FIG. 8 is a partially omitted cross-sectional view along a substantially horizontal direction showing another modification of the armature yoke.
FIG. 9 is a partially omitted cross-sectional view along a substantially horizontal method showing still another modification of the armature yoke.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Linear electromagnetic actuator 12 ... Base member 13 ... Outer yoke 14a, 14b ... Side part 16a, 16b, 60a, 60b, 62 ... Permanent magnet 18 ... Bottom part 20 ... Support block 22 ... Guide rail 24 ... Moving body 26 ... Guide block 28 ... Linear guide 30 ... Coil holder 32a, 32b ... Air gap 34, 52, 56 ... Armature yoke 36a, 36b ... Plate 38a, 38b ... Projection part 40a, 40b ... Coil 42 ... Coil part

Claims (4)

In a linear electromagnetic actuator having a stator and a mover and displacing the mover by a thrust generated based on Fleming's left-hand rule,
An outer yoke having a U-shaped cross section having a pair of side portions and a bottom portion which are made of a magnetic material and arranged to face each other at a predetermined interval;
A set of permanent magnets respectively fixed to a set of sides of the outer yoke;
A first plate disposed between the pair of permanent magnets via an air gap and formed with a first protrusion protruding toward one permanent magnet side, and protruding toward the other permanent magnet side An armature yoke coupled with a second plate on which a second protrusion is formed;
A first coil wound along the circumferential surface of the first plate and a second coil wound along the circumferential surface of the second plate are provided such that coil currents flow in opposite directions. A coil portion having a coil;
A linear electromagnetic actuator comprising: In the linear electromagnetic actuator according to claim 1 Symbol placement,
A linear electromagnetic actuator, wherein the movable element is provided with a moving body that is integrally displaced. The linear electromagnetic actuator according to claim 2 ,
The linear electromagnetic actuator, wherein the moving body is provided with a linear guide for guiding the moving body along an axial direction of the outer yoke. In the linear electromagnetic actuator according to claim 1 Symbol placement,
The linear armature actuator according to claim 1, wherein the armature yoke is formed by alternately connecting a plurality of first plates and second plates.

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