JP2005130603A - Linear electromagnetic actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear electromagnetic actuator which can improve the setup accuracy of a moving member and besides can obtain desired magnetic properties. <P>SOLUTION: This linear electromagnetic actuator generates axial thrust in a moving member by working magnetic force between a stator and the moving member by energizing the coil of the stator. The moving member is constituted by arranging moving member cores and permanent magnets constituting magnetic poles alternately in axial direction. This is equipped with a cylindrical member 210 which is fixed coaxially to the shaft 202 of the moving member 200 and besides has a flange 210a as a support at its axial one end, and a fixing member 211 which is fixed to its axial other end. The moving member cores 201 and the permanent magnets 203 stacked alternately on the periphery of the cylindrical member are pressure-welded and caught by the above flange 210a and the fixing member 211. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a linear electromagnetic actuator in which the structure of a mover that is linearly driven by a magnetic force acting between a stator and a stator is improved.

FIG. 6 is a perspective view showing the prior art of this type of linear electromagnetic actuator, the main part of which is described in Japanese Patent Application No. 2003-356231 which is the prior application of the present applicant.
In FIG. 6, the stator 100 includes rail-shaped (long-shaped) stator pieces 101, 102, 103, and 104 made of a magnetic material having a plurality of protrusions 107 formed on the inner surface along the longitudinal direction. Thus, the annular bridge 120 made of a magnetic material is closely attached to and joined to the end faces on one side in the longitudinal direction of the stator pieces 101 to 104. The bridge 120 is configured by sintering or bonding a magnetic powder material such as ferrite, and has four round corners as viewed from the axial direction. The width along the radial direction is the width of the stator pieces 101 to 104. At the same time, the outer peripheral surface of the bridge 120 is flush with the outer surfaces of the stator pieces 101 to 104.

Further, coils 108, 109, 110, and 111 are intensively wound around the bridge 120 of the stator pieces 101, 102, 103, and 104, respectively.
Further, 116 is a through hole formed at the center of the bridge 120.

  As shown in detail in FIG. 7, concave grooves 121 to 124 that receive these ends corresponding to the stator pieces 101 to 104 are formed on the surface of the bridge 120 that contacts the stator pieces 101 to 104, respectively. Is formed. The width B of these concave groove portions 121 to 124 is slightly longer than the width b of the end portions of the stator pieces 101 to 104 in order to facilitate receiving (contact) the end portions of the stator pieces 101 to 104 ( B> b) formed. Further, the central axis x of the concave groove portions 121 and 122 and the central axis y of the concave groove portions 123 and 124 intersect with each other near the center of the bridge 120 (orthogonal in the illustrated example).

As shown in FIG. 8, when the end surfaces of the stator pieces 101 to 104 are brought into contact with the bottom surfaces of the concave groove portions 121 to 124, the end portions of the stator pieces 101 to 104 that face the inner side surfaces of the concave groove portions 121 to 124, respectively. The relative movements of the bridge 120 and the stator pieces 101 to 104 along the central axis x and y directions are restricted within a predetermined range (corresponding to the gap represented by B-b). . That is, the position within the contact surface of the bridge 120 is constrained.
Furthermore, since the magnetic circuit by the magnetic pole of the mover 200A, which will be described later, is formed through the contact surfaces of the concave grooves 121-124 and the stator pieces 101-104, the bridge 120 and the stator pieces 101-104 A magnetic attraction force is generated therebetween, and the bridge 120 is attracted to the stator pieces 101 to 104 and integrally held and fixed.

For this reason, without using means such as adhesion and screwing, the stator pieces 101 to 104 in the longitudinal direction of the stator pieces 101 to 104 and the directions orthogonal to the longitudinal direction (x and y directions in FIGS. 7 and 8). The bridge 120 and the stator pieces 101 to 104 can be integrally fixed while restricting the position of.
Therefore, the assembling process can be greatly simplified, an adhesive is not required, and the cost can be reduced. Further, there is no need to provide a screw portion for fixing the stator pieces 101 to 104 and the bridge 120, and the magnetic path is not impaired, so that there is no possibility of deteriorating magnetic characteristics, and the bridge 120 and the stator piece 101 are also not affected. The processing for .about.104 does not require high dimensional accuracy except for the contact surfaces of both including the concave groove portions 121-124.

On the other hand, as shown in FIGS. 6 and 9, the mover 200 </ b> A includes a front substantially square first steel plate 201 a that constitutes the convex portion of the magnetic pole and a front substantially square second steel plate 201 b that constitutes the concave portion of the magnetic pole. And a predetermined number (two in this example) are stacked as a unit, and for example, four mover cores 201 that are alternately stacked along the axial direction, and between these mover cores 201 It is comprised from the three permanent magnets 203 which were arrange | positioned and each magnetized along the axial direction, and the axial part 202 to which the needle | mover core 201 and the permanent magnet 203 are fixed.
The mover core 201 and the permanent magnet 203 are alternately stacked and fixed to the shaft portion 202 by means such as press fitting and adhesion.
The mover 200A is disposed in the inner space of the stator 100 so that the shaft portion 202 penetrates the through hole 116 of the stator 100. At this time, the magnetic pole of the mover 200A forms a gap in the protrusion 107 of the stator 100. It is a thing which faces apart.

FIG. 10 is a longitudinal sectional view showing another movable element 200B in the prior art.
In this example, a cylindrical member 204 made of a non-magnetic material is fixed to the shaft portion 202, and the movable member core 201 and the permanent magnet 203 (which penetrate through the centers thereof) having substantially the same configuration as that in FIG. The inner diameters of the through holes are, of course, different from those shown in FIG. 9). These mover cores 201 and the like are also fixed to the cylindrical member 204 by press-fitting or bonding.
By adopting such a configuration, even when a magnetic material such as iron is used as the shaft portion 202, direct magnetic coupling between the mover core 201 and the shaft portion 202 is avoided, and the shaft portion 202 is moved inside. Since the leakage magnetic flux which passes is reduced, the thrust fall of the needle | mover 200B can be suppressed.

Here, the operation of the linear electromagnetic actuator shown in FIG. 6 will be outlined.
The protrusions 107 of the stator pieces 101 to 104 are arranged so as to be sequentially displaced along the longitudinal direction with respect to the adjacent stator pieces. For example, current is passed through the coils 108 and 109 so that the stator piece 101 is When the N pole and the stator piece 102 are excited so as to become the S pole, the S pole of the mover 200A is attracted to the protrusion 107 of the stator piece 101, and the N pole of the mover 200A is attracted to the protrusion 107 of the stator piece 102, respectively. Therefore, the mover 200 moves along the axial direction.
At this time, if the stator piece 103 is passed through the coils 110 and 111 of the other pairs of stator pieces 103 and 104 and excited so that the stator piece 103 has the N pole and the stator piece 104 has the S pole, the S pole of the mover 200A. Is attracted to the protrusion 107 of the stator piece 103 and the N pole of the mover 200A is attracted to the protrusion 107 of the stator piece 104, so that the mover 200 further moves in the same direction.

Next, by passing a current through the coils 108 and 109 in the opposite direction, the mover 200A further moves in the same direction, and then the coils 110 and 111 and the coils 108 and 109 are alternately excited. The thrust can be continuously generated in the mover 200A and moved in one direction.
Note that the current flowing through the coils 108 to 111 is a pulsed or sinusoidal current.

As described above, since this prior art has a three-dimensional structure that surrounds the mover 200A by the stator 100, the space utilization rate of the linear electromagnetic actuator can be improved and the size can be reduced. By canceling out the magnetic attractive force from the shaft, the burden on the mechanism portion such as the shaft portion 202 supporting the mover 200A and its bearing (not shown) is reduced.
Further, if the movable element 200A is formed in a cylindrical shape, it is not necessary to strictly adjust the mounting angle around the axis of the movable element 200A, and the moment due to the magnetic attractive force to the shaft portion 202 is eliminated. The annular bridge 120 is effective in securing a sufficient magnetic path. If the bearing of the shaft portion 202 of the mover 200A is disposed in the through-hole 116 formed therein, the linear electromagnetic actuator can be reduced in size and weight. Can contribute.

  Note that a movable element in which a plurality of stator cores 201 are laminated in the axial direction as shown in FIGS. 6, 9, and 10, and a linear pulse motor having the movable element are disclosed in Patent Documents 1 and 2 below. It is also described in.

Japanese Patent Laid-Open No. 7-170719 (FIGS. 1-4, etc.) Japanese Utility Model Publication No. 6-60284 (FIG. 1, FIG. 5 etc.)

In the above-described conventional movers 200A and 200B, when the mover core 201 is press-fitted and fixed to the shaft portion 202 or the cylindrical member 204, for example, as shown in FIG. 11, deformation caused by press-fitting into the first steel plate 201a or the like. (Warpage) may occur, and a gap may be generated inside the steel plate 201a, between the steel plates 201a and 201b, and between these and the permanent magnet 203. As a result, predetermined assembly accuracy cannot be obtained, and an increase in magnetic resistance causes a problem that the magnetic flux passing through the magnetic path is reduced and the thrust is reduced.
In addition, the steel plates 201a and 201b remain stressed due to the press-fitting, thereby deteriorating the magnetic characteristics and causing the thrust to decrease as described above.

  Furthermore, when the mover core 201 is fixed by adhering to the shaft portion 202 or the cylindrical member 204 instead of press-fitting, it takes time to bond a large number of the steel plates 201a and 201b and the permanent magnet 203 one by one. In addition, the cost is high and the cost is high, and there is a possibility that excess adhesive enters between the steel plates 201a and 201b and the permanent magnet 203, resulting in failure to obtain predetermined assembly accuracy and magnetic characteristics.

  Accordingly, the present invention aims to provide a linear electromagnetic actuator that solves the above-described problems, improves the assembly accuracy of the mover, and obtains desired magnetic characteristics.

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to apply a magnetic force between the stator and the mover by energizing the coil of the stator, and generate a thrust along the axial direction on the mover. In the linear electromagnetic actuator, wherein the mover is configured by alternately laminating a mover core and a permanent magnet constituting a magnetic pole in the axial direction,
A cylindrical member fixed concentrically to the shaft portion of the mover and having a support portion at one end in the axial direction; and a fixing member that can be fixed to the other end in the axial direction of the cylindrical member. The mover core and the permanent magnet, which are alternately stacked on the outer peripheral surface, are pressed and clamped by the support portion and the fixing member.

The invention according to claim 2 is the linear electromagnetic actuator according to claim 1,
The mover core is formed as a unit in which a predetermined number of first steel plates constituting the convex portions of the magnetic poles and second steel plates constituting the concave portions of the magnetic poles are laminated, and the permanent magnet is axially And M (M is an integer of 2 or more) mover cores and M−1 permanent magnets are alternately stacked.

  According to a third aspect of the present invention, in the linear electromagnetic actuator according to the first or second aspect, the cylindrical member is formed in a substantially cylindrical shape, and the first and second steel plates and the permanent magnet constituting the mover core. Further, a through hole having an inner diameter equal to or larger than the outer diameter of the cylindrical member is formed.

The invention according to claim 4 is the linear electromagnetic actuator according to any one of claims 1 to 3,
The fixing member is fixed by press-fitting or bonding to an end portion of the cylindrical member.

The invention according to claim 5 is the linear electromagnetic actuator according to any one of claims 1 to 4,
The member in which the mover core and the permanent magnet are alternately laminated is formed in a substantially cylindrical shape.

The invention according to claim 6 is the linear electromagnetic actuator according to any one of claims 1 to 5,
The cylindrical member and the fixing member are formed of a nonmagnetic material.

The invention according to claim 7 is the linear electromagnetic actuator according to any one of claims 1 to 6,
The stator is concentrated in each stator piece in order to magnetize the stator pieces, and a plurality of stator pieces made of a magnetic body having a plurality of protrusions arranged in a rail shape at a predetermined interval in the longitudinal direction. Each of the stator pieces is arranged substantially in parallel with each other, and the stator piece is arranged at the end of each stator piece and an annular bridge that magnetically couples the stator pieces. As well as
The mover is disposed in an internal space surrounded by the stator pieces, and the protrusion of the stator and the magnetic pole of the mover face each other with a gap therebetween.

  According to the present invention, regardless of the method of press-fitting or bonding the mover core, the mover core and the permanent magnet laminated together along the axial direction of the tubular member are pressed by the support portion of the tubular member and the fixed member. Because of the sandwiching structure, deformation of the steel plate constituting the mover core and entry of the adhesive can be prevented, and assembly accuracy and magnetic characteristics can be improved, productivity can be improved, and cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a first embodiment of the present invention. The same components as those in FIGS. 6 and 10 are denoted by the same reference numerals.

In FIG. 1, 100 is a stator, and its structure is exactly the same as FIG.
Reference numeral 200 denotes a mover, and its structure will be described below with reference to FIG. In FIG. 2, reference numeral 210 denotes a cylindrical member fixed to the shaft portion 202, and a flange 210 a as a support portion is formed at one axial end portion of the cylindrical member 210. Reference numeral 211 denotes an annular fixing member fitted to the other axial end of the cylindrical member 210.

Further, as in FIG. 10, a predetermined number of first substantially square front steel plates 201a constituting the convex portions of the magnetic poles and second substantially square steel plates 201b constituting the concave portions of the magnetic poles (this embodiment). For example, four mover cores 201 in which these are stacked alternately along the axial direction, and three permanent magnets arranged between these mover cores 201 203 is disposed on the outer peripheral surface of the body portion of the cylindrical member 210.
3 is a front view showing the mover core 201, and FIG. 4 is a front view showing the permanent magnet 203. The steel plates 201a and 201b and the permanent magnet 203 have through-holes 201c having an inner diameter equal to or larger than the outer diameter of the body of the cylindrical member 210. , 203a are formed.

  A method for assembling the movable element 200 will be described. First, the shaft portion 202 is inserted into the cylindrical member 210 and the both are integrally fixed. Next, a predetermined number of mover cores 201 and permanent magnets 203 are alternately mounted on the body from the non-flange side end of the cylindrical member 210, and finally the fixing member 211 is press-fitted or bonded to the end of the body. To do. Thereby, the mover core 201 and the permanent magnet 203 are pressed and sandwiched by the flange 210a and the fixed member 211, so that the mover 200 is integrally formed.

In this embodiment, the steel plates 201a and 201b (mover core 201) and the permanent magnet 203 are formed with through holes 201c and 203a that are equal to or slightly larger than the outer diameter of the body of the cylindrical member 210. It can be easily placed on the body of the member 210, and there is no need to press fit. Therefore, an excessive force is not applied to the mover core 201 and the permanent magnet 203, and deformation (warping) and distortion do not occur, so that no gap is generated between the steel plates 201a and 201b and the permanent magnet 203, and the assembly accuracy is improved. There is no risk of lowering the power, increasing the magnetic resistance, or lowering the thrust.
In addition, an actuator having stable magnetic characteristics can be obtained without worrying that stress accompanying press-fitting remains on the steel plates 201a and 201b.

Furthermore, since the mover 200 can be formed simply by laminating the mover core 201 and the permanent magnet 203 around the cylindrical member 210 and press-fitting or bonding the fixed member 211, the productivity is improved and the cost is reduced. can do.
In addition, since the place where the fixing member 211 is bonded is limited, there is no fear that excess adhesive enters between the steel plates 201a and 201b and deteriorates the magnetic characteristics.

  In addition, by forming the cylindrical member 210 and the fixing member 211 with a non-magnetic material, even when a magnetic material such as iron is used for the shaft portion 202, a direct magnetic contact between the mover core 201 and the shaft portion 202 is achieved. The leakage magnetic flux passing through the shaft portion 202 can be reduced by avoiding the coupling.

Next, FIG. 5 is a perspective view of a mover 200 ′ according to another embodiment of the present invention.
In this example, the mover 200 ′ is formed in a substantially cylindrical shape as a whole. In other words, the member in which the mover core 201 ′ and the permanent magnet 203 ′ are alternately stacked is formed in a substantially cylindrical shape.

In FIG. 5, the mover core 201 ′ is configured by laminating a plurality of annular first and second steel plates, and the mover core 201 ′ and the annular permanent magnet 203 ′ are formed on the body of the cylindrical member 210. It is laminated alternately around the part. The press-contacting and clamping structure of the mover core 201 ′ and the permanent magnet 203 ′ by the flange 210a and the fixed member 211 of the cylindrical member 210 is the same as that in FIG.
In this case, it is desirable that the facing surface of the protrusion of the stator piece facing the magnetic pole of the mover 200 ′ is also a curved surface adapted to the outer peripheral surface of the magnetic pole.
According to this embodiment, the first and second steel plates constituting the mover core 201 ′ and the permanent magnet 203 ′ can be laminated without having to consider the position (angle) alignment around the axis. Further improvement.

  In the above embodiments, the case where the number of stator pieces is four has been described. However, the present invention is not limited to this, and the number of stator pieces is generally K (K is an integer of 3 or more). It is applicable to the case of piece.

It is a perspective view which shows embodiment of this invention. It is a longitudinal cross-sectional view of the needle | mover in embodiment. It is a front view of the needle | mover core in embodiment. It is a front view of the permanent magnet in an embodiment. It is a perspective view of the needle | mover in other embodiment of this invention. It is a perspective view of a prior art. It is explanatory drawing of the principal part in a prior art. It is explanatory drawing of the principal part in a prior art. It is a longitudinal cross-sectional view of the needle | mover in a prior art. It is a longitudinal cross-sectional view of the needle | mover in a prior art. It is a longitudinal cross-sectional view of the needle | mover in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100: Stator 101-104: Stator piece 107: Protrusion 108-111: Coil 116: Through-hole 120: Bridge 200,200 ': Movable element 201, 201': Movable element core 201a, 201b: Steel plate 201c: Through-hole 202: Shaft part 203, 203 ': Permanent magnet 203a: Through hole 210: Cylindrical member 210a: Flange (support part)
211: Fixed member

Claims (7)

A linear electromagnetic actuator that energizes a coil of a stator to cause a magnetic force to act between the stator and the mover, and generates a thrust along the axial direction on the mover, the mover having a magnetic pole In a linear electromagnetic actuator configured by alternately laminating and arranging a mover core and a permanent magnet in the axial direction,
A cylindrical member fixed concentrically to the shaft of the mover and having a support at one end in the axial direction;
A fixing member that can be fixed to the other axial end of the cylindrical member,
A linear electromagnetic actuator, wherein the mover core and the permanent magnet, which are alternately stacked on the outer peripheral surface of the cylindrical member, are pressed and clamped by the support portion and the fixing member. The linear electromagnetic actuator according to claim 1,
The mover core is formed as a unit in which a predetermined number of first steel plates constituting the convex portions of the magnetic poles and second steel plates constituting the concave portions of the magnetic poles are laminated, and the permanent magnet is axially A linear electromagnetic actuator characterized in that M (M is an integer of 2 or more) mover cores and M-1 permanent magnets are alternately stacked. The linear electromagnetic actuator according to claim 1 or 2,
The cylindrical member is formed in a substantially cylindrical shape, and a through hole having an inner diameter equal to or larger than an outer diameter of the cylindrical member is formed in the first and second steel plates and the permanent magnet constituting the mover core. Linear electromagnetic actuator. In the linear electromagnetic actuator according to any one of claims 1 to 3,
A linear electromagnetic actuator, wherein the fixing member is fixed by press-fitting or adhering to an end of the cylindrical member. In the linear electromagnetic actuator according to any one of claims 1 to 4,
A linear electromagnetic actuator characterized in that a member in which the mover core and permanent magnet are alternately laminated is formed in a substantially cylindrical shape. In the linear electromagnetic actuator according to any one of claims 1 to 5,
A linear electromagnetic actuator characterized in that the cylindrical member and the fixing member are formed of a non-magnetic material. In the linear electromagnetic actuator according to any one of claims 1 to 6,
The stator is concentrated in each stator piece in order to magnetize the stator pieces, and a plurality of stator pieces made of a magnetic body having a plurality of protrusions arranged in a rail shape at a predetermined interval in the longitudinal direction. Each of the stator pieces is arranged substantially in parallel with each other, and the stator piece is arranged at the end of each stator piece and an annular bridge that magnetically couples the stator pieces. As well as
A linear electromagnetic actuator characterized in that the mover is arranged in an internal space surrounded by these stator pieces, and a projection of the stator and a magnetic pole of the mover face each other with a gap.

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