JP4534194B2 - Moving coil type linear motor and magnetic circuit assembling method thereof - Google Patents

Description

  The present invention provides a high-precision moving coil linear motor suitable for an alignment stage drive mechanism used in, for example, a semiconductor manufacturing apparatus, a flat display manufacturing apparatus, a printed board manufacturing apparatus, or various inspection apparatuses, and a magnetic field of a stator thereof. The present invention relates to a circuit assembly method.

Patent Document 1 discloses a high-accuracy moving coil linear motor suitable for positioning shown in FIG. 10A (cross-sectional view) and FIG. 10B (cross-sectional view taken along line AA in FIG. 10A). It is disclosed.
In the linear motor of FIG. 10, 2b is a magnet, 6 is a base, 7 is a mover, 8 is a supporting sliding member, 5 is a coil, 9 is a coil frame, 10 is It is a short plate. Two main magnets 2a and two auxiliary magnets 2b are placed on the short plate 10 to form a short plate 11 with magnet, and the short plate 11 with magnet is the traveling direction of the mover 7. A predetermined number is arranged along. The assembly of the magnetic circuit of this linear motor is carried out by placing a magnet array composed of two main magnets 2a and two auxiliary magnets 2b on a short plate 10 in advance to form a short plate 11 with magnets. The short plate 11 with magnet is disposed on the inner surface of the integrally structured base 6 having a substantially U-shaped cross section.

Patent Document 2 discloses a single-axis stage of a movable coil type linear motor shown in FIG. 11 (a) and FIG. 11 (b) (a cross-sectional view taken along line A′-A ′ in FIG. 11A). ing.
In FIG. 11, 101 is a linear motor, 101a is a U-shaped split yoke, 101b is a permanent magnet, 101c is a coil (movable part), 102 is a guide part, Reference numeral 103 denotes a cable bear.

Patent Document 3 discloses a magnetic circuit of a stator of a moving coil linear motor shown in FIG. 12 (side view).
In FIG. 12, 121 denotes a magnet yoke, 122 denotes an upper facing portion constituting an integral yoke having a substantially U-shaped cross section, and 123 denotes a lower side constituting an integral yoke having a substantially U-shaped cross section. 124 is a connecting side portion for connecting the two. 130 and 131 are magnets, 127 and 128 are opposing yoke surfaces, 125a is a screw hole, 132 is a gap, and 132a is a side opening.
Japanese Unexamined Patent Publication No. 2003-32996 (Claims 8, 8, and 9) Japanese Patent Laying-Open No. 2003-121573 (FIG. 10) JP 2000-333435 A (FIG. 9)

However, in the method for assembling a magnetic circuit of a moving coil linear motor using a magnet-attached short plate described in Patent Document 1, (1) using an integrated structure base having a substantially U-shaped cross section. (2) A pair of short plates with magnets are arranged on the inner surface of the base whose cross-sectional shape is formed in a substantially U-shape. Since the assembly work is performed under adverse conditions in which the strong suction / repulsive force between the short plates with magnets acts in the inner space, there is a problem that the skill and perseverance of the operator is required and the work efficiency is very poor. This poor assembly workability is becoming an increasingly serious problem as the magnetic flux density of the magnetic air gap increases with the recent increase in thrust of the linear motor.
In the moving coil type linear motor described in Patent Document 2, since the yoke 101a having a U-shaped cross section has a yoke assembly composed of three yoke plates, the U-shaped yoke having an integral structure is processed and formed. Compared to the case, the processing cost is lower. However, the magnetic circuit of this linear motor is assembled after a yoke assembly 101a having a U-shaped cross section is assembled from three divided yoke plates, and then a pair of inner surfaces facing each other of the yoke assembly 101a via a gap. The operation is to bond the permanent magnets 101b and 101b. This bonding work is expensive and inferior in workability like the magnetic circuit assembling work of Patent Document 1, and improvement has been demanded.
In the moving coil type linear motor described in Patent Document 3, an integral yoke having a substantially U-shaped cross section is used for the stator. However, as in Patent Document 1, the processing cost of the integral yoke is expensive, and As in Patent Documents 1 and 2, the work of bonding the permanent magnet on the integral yoke is inferior in workability.

  Therefore, the problem to be solved by the present invention is that a high-performance movable coil linear motor and its stator that have good assembly workability, reduce the processing cost of the yoke (base), and reduce thrust ripple. A method for assembling a magnetic circuit is provided.

  The moving coil type linear motor of the present invention that has solved the above problems includes a stator including a yoke and a permanent magnet and a magnetic circuit having a substantially U-shaped cross section, and the magnetic circuit. A movable coil type linear motor comprising a magnetic gap formed and a mover configured to run in the magnetic gap while having a multiphase coil, the magnetic circuit comprising a permanent magnet, a center yoke, and a center A plurality of side yokes sandwiching and abutting the yoke, and at least one of the side yokes is divided into a plurality along the travel direction of the mover and faces the travel path of the mover. A permanent magnet is placed on the yoke.

  In the linear motor of the present invention, the side yoke includes a first side yoke and a second side yoke that are in contact with and sandwiching the center yoke, and a third side that is in contact with the first side yoke and is opposed to the second side yoke through a gap. A first permanent magnet row comprising a plurality of permanent magnets disposed on the second side yoke and a second permanent magnet row comprising a plurality of permanent magnets disposed on the third side yoke. In the case where a pair of permanent magnet arrays facing each other through a gap is formed, the assemblability is good and the thrust becomes large, so that the practicality is high.

  In the linear motor of the present invention, when the center yoke side or the side yoke side in the vicinity of the position where the side yoke and the center yoke abut are chamfered, the cross-sectional shape is substantially the same without excessively increasing the thickness of the yoke. Since the bending amount of the Y-shaped yoke assembly can be kept small and the thrust ripple can be reduced, it is highly practical.

  The linear motor of the present invention is highly practical when used in a state where a pair of opposing permanent magnet rows are in a vertical positional relationship via a magnetic gap.

A method of assembling a magnetic circuit of a stator of a moving coil linear motor according to the present invention includes a center yoke, a first side yoke and a second side yoke that are in contact with the center yoke and are in contact with the first side yoke. A yoke assembly having a substantially U-shaped cross section including a two-side yoke and a third side yoke facing each other through a gap, the second side yoke and the third side facing each other in the yoke assembly; A pair of permanent magnet rows are arranged on the yoke so as to face each other through a gap, and the second side yoke and / or the third side yoke are divided into a plurality along the arrangement direction of the permanent magnet rows. A method of assembling a magnetic circuit of a stator of a movable coil linear motor having a second side yoke piece and / or a third side yoke piece, the center yoke and the first side yoke And a second side yoke piece with magnet on which a plurality of permanent magnets are placed and a third side with magnet on which a plurality of permanent magnets are placed. The yoke piece is brought into a state of being opposed to each other through a gap, and then the third side yoke piece with the magnet in the opposed state is brought into contact with and fixed on the first side yoke of the substantially L-shaped yoke assembly, A magnetic circuit having a substantially U-shaped cross-section is formed by abutting and fixing a center yoke of the substantially L-shaped yoke assembly and the second side yoke piece with magnets in an opposed state. .
According to the assembling method of the present invention, the rigidity of the magnetic circuit after assembling is maintained by the rigidity of the center yoke and the first side yoke of the integral structure, and the cross-sectional shape of the inner space of the base is substantially U-shaped. Since the assembly work load can be greatly reduced, the assembly work can be performed easily and with high accuracy, and the processing cost can be reduced.

In the method of assembling the magnetic circuit of the stator of the moving coil linear motor of the present invention, an operation of fixing the center yoke and the first side yoke to form a yoke assembly having a substantially L-shaped cross section, and a plurality of permanent The work of making the second side yoke piece with magnets on which the magnet is placed and the third side yoke piece with magnets on which the plurality of permanent magnets are placed facing each other through the gap is performed first. May be. The means for causing the second side yoke piece with magnet and the third side yoke piece with magnet to face each other through a gap is not particularly limited. For example, a nonmagnetic spacer (for example, made of resin) is provided between the two. The method of joining both by the magnetic attraction force which acts between both in the state pinched | interposed is mentioned.
In the method of assembling the magnetic circuit of the stator of the moving coil type linear motor of the present invention, the third side yoke piece with the magnet in contact is brought into contact with the first side yoke of the substantially L-shaped yoke assembly. The work of fixing the center yoke of the substantially L-shaped yoke assembly and the work of fixing the second side yoke piece with magnets facing each other may be performed first. .

  According to the present invention, there is provided a high-performance moving-coil linear motor that has good assembling workability, a low yoke (base) processing cost, and reduced thrust ripple, and a method for assembling the stator thereof. be able to.

  Hereinafter, a moving coil linear motor and a method of assembling a stator thereof according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view perpendicular to the traveling direction of a mover showing an embodiment of the moving coil linear motor of the present invention. FIG. 2 is a cross-sectional view of the magnetic circuit portion of FIG.
In the moving coil type linear motor 40 shown in FIGS. 1 and 2, reference numeral 42 denotes an integral structure extending in a direction perpendicular to the paper surface and a ferromagnetic center yoke (for example, made of SS400). Chamfered portions 42 a and 42 a are provided at both upper ends of the center yoke 42. By providing the chamfered portion 42 a, it is possible to reduce the amount of bending caused by the magnetic attraction / repulsion force acting between the opposing side yokes 43, 45, 44, and hence the thrust ripple of the movable coil linear motor 40. Can be reduced. Reference numeral 43 denotes a ferromagnetic first side yoke (for example, made of SS400), which is an integral structure extending in a direction perpendicular to the paper surface. Reference numeral 44 denotes a ferromagnetic second side yoke (for example, made of SS400), which includes a plurality of second side yoke pieces 44a, 44b (for example, 10 divided pieces) extending in a direction perpendicular to the paper surface. Reference numeral 52 denotes a boundary of the second side yoke piece. Reference numeral 45 denotes a ferromagnetic third side yoke (for example, made of SS400), which includes a plurality of third side yoke pieces 45a, 45b (for example, 10 divided pieces) extending in a direction perpendicular to the paper surface. 53 is a boundary of the third side yoke piece. The flat portion 42b at the left end of the center yoke 42 and the stepped portion 44e of the second side yoke are in contact with each other and are fastened by screws (not shown). Fastened with screws (not shown) in a state where the flat portion 42b at the right end of the center yoke 42 and the stepped portion 43c of the first side yoke are in contact with each other. The third side yoke pieces 45a, 45b,... Are in contact with the stepped portion 43d of the first side yoke and are fastened with screws (not shown), and the permanent magnet 41 is bonded thereon. A permanent magnet 41 is bonded to the step portion 44d of the second side yoke piece. As shown in FIG. 2, the pair of permanent magnets 41 and 41 is composed of a pair of opposed permanent magnet rows (a first permanent magnet row 410 and a second permanent magnet row 411). In the first permanent magnet row 410, auxiliary magnets 41b oriented in the horizontal direction and main magnets 41a oriented in the vertical direction are alternately arranged from the left end side. That is, the main magnet 41a and the auxiliary magnet 41b are alternately arranged, and the magnetic poles of the main magnet 41a are alternately arranged on the magnetic air gap 51 side so that different polarities appear alternately, and the main magnet appearing on the magnetic air gap 51 side. The main magnet 41a is sandwiched and disposed so that the magnetic poles of the auxiliary magnet 41b having the same polarity as the magnetic pole of 41a face each other. The arrangement of the permanent magnets in the second permanent magnet row 411 is the same, and the magnetic poles of the pair of main magnets 41a, 41a facing each other via the magnetic gap 51 form a so-called Halbach type magnetic circuit in which the opposite polarities are comrades. The center yoke 42 and the side yokes 43, 44, 45 form a yoke assembly 54 having a substantially U-shaped cross section. The yoke assembly 54 and the permanent magnet 41 constitute a stator magnetic circuit 50 having a substantially U-shaped cross section.
Reference numeral 46 denotes a multiphase coil (for example, a three-phase coil). Reference numeral 49 denotes a coil frame, which is connected to a table 47 constituting the mover. The mover 47 is movable in a direction perpendicular to the paper surface via supporting sliding members (for example, linear motor guides) 48, 48 provided on the upper portion of the stator 50.

A method of assembling the stator magnetic circuit 50 shown in FIGS.
First, the right end flat surface 42b of the center yoke 42 and the stepped portion 43c of the first side yoke are screwed together to form a yoke assembly having a substantially L-shaped cross section. Next, a plurality of permanent magnets 41 are bonded onto the third side yoke pieces 45a, 45b,... To form a predetermined number of third side yoke pieces with magnets. In parallel, a plurality of permanent magnets 41 are bonded onto the second side yoke pieces 44a, 44b... To form a predetermined number of second side yoke pieces with magnets.
Next, one piece of the second side yoke piece with magnet and one piece of the third side yoke piece are joined together by a magnetic attraction force acting between them with a non-magnetic spacer (not shown) having a predetermined thickness interposed therebetween. This pair of joined bodies is prepared in a number corresponding to the travel stroke of the mover 47 of the moving coil linear motor 40.
A stepped portion of the first side yoke of the substantially L-shaped yoke assembly is formed by connecting the third side yoke piece with a magnet in a state of being joined to the second side yoke piece by sandwiching the nonmagnetic spacer (not shown). Screwed in contact with 43d. In parallel, the left end flat surface 42b of the center yoke 42 of the substantially L-shaped yoke assembly and the stepped portion 44e of the second side yoke piece with magnet on one side in the joined state are screwed together. . In this way, the pair of magnet-attached side yoke pieces are incorporated into the substantially L-shaped yoke assembly. In this manner, a plurality of pairs of magnetized second side yoke pieces and third side yoke pieces, which are finally matched to the travel stroke of the moving coil linear motor 40, are sequentially provided in the center yoke 42 of the substantially L-shaped yoke assembly. In addition, a magnetic circuit having a substantially U-shaped cross section is formed by being assembled to the first side yoke 43.
In the assembling method, the third side yoke piece with magnet in a state of being joined to the second side yoke piece with the nonmagnetic spacer (not shown) interposed between the first side of the substantially L-shaped yoke assembly. The work of screwing in a state of being in contact with the stepped portion 43d of the side yoke, and the second side yoke piece 1 with the magnet on one side in the joined state with the left end flat surface 42b of the center yoke 42 of the substantially L-shaped yoke assembly. Either of the work of screwing in a state where the stepped portion 44e of the piece is in contact may be performed first.
As a modification of the assembling method, the number of the second side yoke pieces with magnets and the third side yoke pieces to be joined by a magnetic attraction force with a non-magnetic spacer (not shown) having a predetermined thickness interposed therebetween is two or more. Also good.

FIG. 3 is a cross-sectional view perpendicular to the traveling direction of the mover, showing another embodiment relating to the moving coil linear motor of the present invention. FIG. 4 is an example of a cross-sectional view taken along the line CC of the magnetic circuit portion of FIG.
In the moving coil linear motor 60 shown in FIGS. 3 and 4, reference numeral 62 denotes an integral structure extending in a direction perpendicular to the paper surface and a ferromagnetic center yoke (for example, made of SS400). Chamfered portions 62a and 62a are provided at the upper ends of both ends of the center yoke 62, and the amount of bending caused by magnetic attraction / repulsive force acting between the opposing side yokes 63, 65 and 64 can be reduced. Accordingly, the thrust ripple of the moving coil linear motor 60 can be reduced. Reference numeral 63 denotes a ferromagnetic first side yoke (for example, made of SS400), which is an integral structure extending in a direction perpendicular to the paper surface. The outer side surface 63 a of the first side yoke is a mounting surface (reference surface) to the base 70. Reference numeral 64 denotes a ferromagnetic second side yoke (for example, manufactured by SS400), which includes a plurality of second side yoke pieces 64a, 64b (for example, 20 divided pieces) extending in a direction perpendicular to the paper surface. Reference numeral 72 denotes a boundary of the second side yoke piece. Reference numeral 65 denotes a ferromagnetic third side yoke (for example, manufactured by SS400), which includes a plurality of third side yoke pieces 65a, 65b (for example, 20 divided pieces) extending in a direction perpendicular to the paper surface. 73 is a boundary of the third side yoke piece. The flat plate 62b at the left end of the center yoke 62 and the stepped portion 64e of the second side yoke are in contact with each other and are fastened by screws (not shown). The center portion 62 is fastened by a screw (not shown) in a state where the flat portion 62b at the right end of the center yoke 62 and the stepped portion 63c of the first side yoke are in contact with each other. The third side yoke pieces 65a, 66b,... Are in contact with the stepped portion 63d of the first side yoke with screws (not shown), and the permanent magnet 61 is bonded thereon. A permanent magnet 61 is bonded to the step portion 64d of the second side yoke pieces 64a, 64b. As shown in FIG. 4, the pair of permanent magnets 61, 61 includes a pair of opposed permanent magnet rows (first permanent magnet row 610 and second permanent magnet row 611). In the first permanent magnet row 610, from the left end side, auxiliary magnets 61b oriented in the horizontal direction and main magnets 61a oriented in the vertical direction are alternately arranged, and the magnetic poles of the main magnet 61a are alternately arranged on the magnetic gap 71 side. Are arranged so that different polarities appear, and the main magnet 61a is sandwiched so that the magnetic poles of the auxiliary magnet 61b having the same polarity as the main magnet 61a appearing on the magnetic gap 71 side face each other. The arrangement of the permanent magnets in the second permanent magnet row 611 is the same, and the magnetic poles of the pair of main magnets 61a, 61a facing each other via the magnetic gap 71 form a Halbach type magnetic circuit in which different polarities exist. The center yoke 62 and the side yokes 63, 64, 65 form a yoke assembly 77 having a substantially U-shaped cross section. The yoke assembly 77 and the permanent magnet 61 constitute a magnetic circuit 78 having a substantially U-shaped cross section.
Reference numeral 66 denotes a multiphase coil (for example, a three-phase coil), and reference numeral 69 denotes a coil frame, which is connected to the mover 67. The mover 67 is movable in a direction perpendicular to the paper surface via supporting sliding members (for example, linear motor guides) 68 and 68 provided on the upper portion of the stator 75.
The assembly method of the magnetic circuit 78 is the same as that of the linear motor 40 of FIG. 1. The linear motor 60 provided with this magnetic circuit 78 has a pair of opposing permanent magnet rows 610 and 611 arranged vertically with a magnetic gap 71 therebetween. It is suitable for applications that are used in a positional relationship.

FIG. 5 is another example of a cross-sectional view taken along the line CC of the magnetic circuit portion of the linear motor 60 of FIG.
In FIG. 5, the pair of permanent magnets 61, 61 in FIG. 3 includes a pair of permanent magnet rows (a first permanent magnet row 620 and a second permanent magnet row 621). Both the first and second permanent magnet rows 620 and 621 are arranged such that main magnets 61a ′ oriented in the longitudinal direction are sequentially arranged from the left end side so that different polarities appear alternately on the magnetic gap 71 ′ side, The magnetic poles of the pair of main magnets 61a ′ and 61a ′ opposed via the magnetic gap 71 ′ have a magnetic circuit configuration of different polarities.

In the magnetic circuit of the linear motor of the present invention, the shape of the chamfered portion provided in the center yoke or the side yoke is not limited to a flat surface, but may be a convex surface or a concave surface, but it is preferable that the chamfer width w is 2 to 20 mm. 5 to 15 mm is more preferable. Providing the chamfered portion is very effective for improving the efficiency of assembly work in the Halbach magnetic circuit with particularly strong magnetic attraction / repulsion force and for suppressing the bending of the yoke assembly having a substantially U-shaped cross section. If the width dimension w of the chamfered portion is less than the above range, the effect of suppressing the bending cannot be obtained, and if it exceeds the above range, the magnetic circuit is increased in size and the practicality is lowered.
The chamfer angle of the chamfered portion is preferably 30 to 60 degrees. When the chamfering angle is out of the above range, the effect of suppressing the bending tends to decrease.

In the magnetic circuit of the linear motor of the present invention, the number of permanent magnets placed on the second and third side yoke pieces is not particularly limited, but the second and third side magnets are considered in consideration of magnetic attraction / repulsive force during assembly. Each of the yoke pieces is preferably 2 to 30 pieces, more preferably 4 to 15 pieces. If the number of arrangements per piece of the second and third side yoke pieces is two or less, there is no practicality, and if it exceeds 30, the magnetic attraction / repulsive force at the time of assembling increases and the assembling work becomes difficult.
The number of the second and third side yoke pieces depends on the stroke of the mover, the dimensions of the permanent magnet and the yoke, and is not particularly limited, but it is practical to use 5 to 50 pieces per magnetic circuit. It is more practical to use ~ 30 pieces. Outside this range, assembly efficiency and accuracy are reduced.

FIG. 6 is a cross-sectional view perpendicular to the traveling direction of the mover, showing still another embodiment relating to the moving coil linear motor of the present invention.
The moving coil linear motor 80 shown in FIG. 6 is the same as the moving coil linear motor 80 shown in FIG. 3 except that a flat ferromagnetic yoke (integral structure, for example, made of SS400) having no chamfered portion is used as the center yoke 82. Since the configuration is the same as that of No. 60 and the assembly method is the same, the description is omitted.

FIG. 7 is a cross-sectional view perpendicular to the traveling direction of the moving coil linear motor, showing still another embodiment relating to the magnetic circuit of the moving coil linear motor of the present invention.
In the magnetic circuit 278 of FIG. 7, reference numeral 262 denotes a plate-shaped ferromagnetic center yoke (integral structure, for example, made of SS400) that extends in a direction perpendicular to the paper surface. Reference numeral 263 denotes a first side yoke (integral structure, for example, made of SS400) that extends in a direction perpendicular to the paper surface, and a chamfered portion 263a is provided on the side that is in contact with and fastened to the center yoke 262. Reference numeral 264 denotes a second side yoke 264 (for example, made of SS400, 15 divided pieces) that extends in a direction perpendicular to the paper surface. Is provided. A permanent magnet 261 is placed on the step portion 264d of the second center yoke. A third side yoke 265 on which a permanent magnet 261 is placed is fixed to the step portion 263d of the first side yoke. The third side yoke 265 is composed of a plurality of pieces extending in a direction perpendicular to the paper surface (for example, made of SS400, 15 divided pieces). A pair of permanent magnets 261 and 261 are opposed to each other with a magnetic gap 271 therebetween. Reference numeral 263b denotes a mounting surface to a base or the like (not shown).
The magnetic circuit 278 is different from the magnetic circuit 78 of FIG. 3 in that chamfered portions 263a and 264a are provided not on the center yoke but on the side yoke, but the other configurations are the same. Therefore, the assembly method of the magnetic circuit 278 is the same as the assembly method of the magnetic circuit 78 of FIG.
In the magnetic circuit 278, the side yoke is provided with the chamfered portions 263a and 264a, so that when the magnetic circuit 278 is incorporated in the movable coil type linear motor, the amount of deflection generated on the opening side facing the magnetic gap 271 of the magnetic circuit 278 due to the magnetic attraction force. Since it can be reduced, thrust ripple can be reduced, and a highly accurate moving coil linear motor can be configured.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by these Examples.
Example 1
The main magnet 61a (NdFeB based anisotropic sintering made by Hitachi Metals, Ltd. having a thickness Tm of 22.5 mm, a length Lm1 of 27 mm, and a height Hm of 88 mm, having the shape shown in FIGS. Magnet, product name: HS55AH), auxiliary magnet 61b (NdFeB anisotropic sintered magnet having a thickness Tm of 22.5 mm, a length Lm2 of 27 mm, and a height Hm of 88 mm, product name: HS55AH), center yoke 62 ( Made of SS400, thickness Tc is 26 mm, chamfered portion 62a has a width w of 5 mm and is chamfered to C5), first side yoke 63 (made of SS400, thickness Ts1 is 11.8 mm), second side yoke piece 64 (SS400 Made, thickness Ts2 is 21.8 mm, divided into 20 in the stroke direction), and third side yoke piece 65 (made from SS400, thickness Ts3 is 10 mm, stroke direction Using the 20 divided are), the assembled magnetic circuit 78 for moving-coil linear motor 60 of FIG. 3, to constitute a linear motor 60 has.
As a result of measuring the deflection amounts δ1 and δ2 of the opening-side end points Q and S of the magnetic circuit 78 incorporated in the linear motor 60, it was found that the level was practically satisfactory. As shown in FIG. 8A, the deflection amount δ1 is obtained when the tangent line E is drawn from the fastening side end face 64b of the second side yoke 64 along the outer side face 64j, and further the tangent line F is drawn from the opening side end face 64t. The distance between the position P where the two intersect and the opening-side end point Q was measured to obtain the deflection amount δ1. When the tangent line G is drawn from the fastening side end surface 63b of the first side yoke 63 along the mounting surface 63a and the tangent line H is further drawn from the opening side end surface 63t, the deflection amount δ2 is the position R where the two intersect and the opening side end point. The distance from S was measured to obtain the amount of deflection δ2.
FIG. 9 shows a typical measurement example of thrust-stroke characteristics in the stable running state (stroke 3000 mm) of the linear motor 60. In FIG. 9, the vertical axis represents the mover thrust value, and the horizontal axis represents the travel stroke value of the mover when the arbitrary position is the origin. From FIG. 9, it was found that the thrust ripple was suppressed to 4%, and the accuracy was equal to or higher than that of the conventional moving coil linear motor. The thrust ripple is defined by (maximum thrust value in a stable running state−minimum thrust value in a stable running state) ÷ (average thrust value in a stable running state) × 100 (%).

(Example 2)
As the center yoke 82 of the magnetic circuit 98 of the moving coil linear motor 80 of FIG. 6, the one made of SS400 and having a thickness Tc ′ of 26 mm was used. All other components were the same as those in the first embodiment, and the magnetic circuit 98 was assembled to form the linear motor 80 shown in FIG. The amount of deflection (δ1 + δ2) of the magnetic circuit 98 of the linear motor 60 was measured in the same manner as in Example 1. As a result, the amount of deflection (δ1 + δ2) was about twice that in Example 1, and the thrust ripple was about 8 However, there was no practical problem.

(Comparative example)
An integral structure yoke having a substantially U-shaped cross-section, which was processed into the same shape and dimensions as the yoke assembly 77 consisting of four divided yokes constituting the magnetic circuit 78 of FIG. 3, was prepared. A moving coil linear motor was constructed in the same manner as in Example 1 except that this integral structure yoke was incorporated in place of the yoke assembly 77 of FIG. The thrust ripple of this linear motor was almost the same as in the first embodiment.

In the magnetic circuit of the linear motor of the present invention, the permanent magnet thickness (Tm) and the center yoke thickness (Tc) are used to increase the magnetic flux density distribution of the magnetic gap and bring it closer to a sine wave and to suppress the deflection amounts δ1 and δ2. ) And the thickness of the side yoke (Ts: the thickness of the second side yoke Ts2 or the sum of the thicknesses of the first and third side yokes (Ts1 + Ts3)), Tc ≧ Tm ≧ Ts in a range where there is no practical problem. It is preferable that Tc>Tm> Ts.
Further, in the magnetic circuit for a linear motor of the present invention, in order to increase the magnetic flux density distribution of the magnetic gap and bring it closer to a sine wave, and to suppress the deflection amounts δ1 and δ2, regarding the yoke thickness, Ts2 = 0.7 (Ts1 + Ts3) To 1.3 (Ts1 + Ts3) is preferable, and Ts2 = 0.8 (Ts1 + Ts3) to 1.2 (Ts1 + Ts3) is more preferable.
Note that the ratio of the thicknesses of Ts1 and Ts3 may be set as appropriate in consideration of the efficiency and accuracy of assembly work.

In the above-described embodiments and examples, the case where the center yoke and the first side yoke constituting the magnetic circuit of the linear motor of the present invention are integrated structures has been described. However, in applications where the rigidity of the magnetic circuit is not strict, The first side yoke may be composed of a plurality of pieces, and the center yoke and the first side yoke may be composed of a plurality of pieces.
In the above-described embodiments and examples, the case of a three-phase coil has been described, but there is no problem in configuring the movable coil linear motor of the present invention even in the case of a two-phase or four-phase or more multi-phase coil.
In the above embodiments and examples, NdFeB block permanent magnets are used. However, the present invention is not particularly limited, and appropriate materials and shapes can be used.

It is sectional drawing perpendicular | vertical with respect to the moving direction of a needle | mover which shows an example of the movable coil type | mold linear motor (vertical type) of this invention. 2 is a cross-sectional view of the magnetic circuit portion of FIG. It is sectional drawing perpendicular | vertical with respect to the moving direction of a needle | mover which shows an example of the movable coil type | mold linear motor (horizontal type) of this invention. FIG. 4 is an example of a cross-sectional view taken along line CC of the magnetic circuit portion of FIG. 3. It is sectional drawing which shows the other structural example of the magnetic circuit of the moving coil type | mold linear motor of this invention. It is sectional drawing perpendicular | vertical with respect to the moving direction of a needle | mover which shows the other example of the movable coil type | mold linear motor (horizontal type) of this invention. It is sectional drawing perpendicular | vertical with respect to a running direction which shows the further another structural example of the magnetic circuit of the moving coil linear motor of this invention. It is a figure explaining the measuring point of the amount of bending of a magnetic circuit (a), and a figure explaining the size of a permanent magnet (b). It is a figure which shows an example of the measurement result of the thrust ripple of the moving coil linear motor of this invention. It is sectional drawing (a) perpendicular | vertical with respect to the moving direction of a needle | mover which shows the conventional moving coil type | mold linear motor, and AA arrow sectional drawing (b) of (a). It is the external view (a) which shows the conventional movable coil type | mold linear motor, and A'-A 'arrow sectional drawing (b). The side view of the magnetic circuit for stators of the conventional moving coil type linear motor is shown.

Explanation of symbols

40, 60, 80: linear motor,
41, 61, 81, 261: permanent magnet,
41a, 61a, 61a ′: main magnet, 41b, 61b: auxiliary magnet,
42, 62, 82, 262: Center yoke,
42a, 62a, 263a, 264a: chamfered portions,
42b, 62b: end plane portions,
43, 63, 63 ′, 83, 263: first side yoke,
43a, 63a, 83a, 263b: mounting surface,
43c, 43d, 44d, 44e, 63c, 63d, 64d, 64e, 83c, 83d, 84d, 84e, 263d, 264d: steps,
44, 64, 84, 263, 264: second side yoke,
44a, 44b, 64a, 64b, 64a ′, 64b ′: second side yoke pieces,
46, 66, 86: polyphase coil,
45, 65, 85, 265: third side yoke,
45a, 45b, 65a, 65b, 65a ′, 65b ′: third side yoke pieces,
47, 67, 87: Movable element (table),
48, 68, 88: support sliding member (linear motor guide),
49, 69, 89: coil frame,
51, 71, 71 ′, 91, 271: magnetic gap,
52, 53, 72, 73: boundary,
50, 75, 95: stator,
54, 77, 97: Yoke assembly,
70, 90: base,
78, 98, 278: magnetic circuit,
410, 610: first permanent magnet row,
411,611: 2nd permanent magnet row | line | column.

Claims (5)

  A center yoke, a first side yoke and a second side yoke that contact each other with the center yoke interposed therebetween to form a magnetic air gap, and a third side that contacts the first side yoke and opposes the second side yoke via the magnetic air gap A yoke composed of a yoke, a first permanent magnet array composed of a plurality of permanent magnets disposed on the magnetic air gap facing surface of the second side yoke, and a magnetic air gap facing surface of the third side yoke. A stator having a magnetic circuit having a substantially U-shaped cross-section with a pair of permanent magnet rows made of a plurality of second permanent magnet rows made of a plurality of permanent magnets, and capable of running in the magnetic gap A movable element having a multi-phase coil configured, and the second side yoke and the third side yoke are divided into a plurality of directions in the same direction as the travel direction of the multi-phase coil. The Moving-coil linear motor. The moving coil linear motor according to claim 1, wherein the center yoke is an integral structure, and the first side yoke is an integral structure. The center yoke or the side yoke is chamfered in the vicinity of the position where the side yoke and the center yoke abut, the chamfering width is 2 to 20 mm, and the chamfering angle is 30 to 60 degrees. The moving coil type linear motor described.   4. The moving coil linear motor according to claim 1, wherein the pair of opposed permanent magnet rows is used in a state where the upper and lower positions are in a vertical relationship via a magnetic gap. A center yoke, a first side yoke and a second side yoke that contact each other with the center yoke interposed therebetween to form a magnetic air gap, and a third side that contacts the first side yoke and opposes the second side yoke via the magnetic air gap A yoke composed of a yoke, a first permanent magnet array composed of a plurality of permanent magnets disposed on the magnetic air gap facing surface of the second side yoke, and a magnetic air gap facing surface of the third side yoke. A stator having a magnetic circuit having a substantially U-shaped cross-section with a pair of permanent magnet rows made of a plurality of second permanent magnet rows made of a plurality of permanent magnets, and capable of running in the magnetic gap And a second side yoke piece and a second side yoke piece divided into a plurality of portions in the same direction as the travel direction of the multiphase coil. A third side moving-coil linear motor assembly methods from the yoke piece is constructed, the cross-sectional shape to form the yoke assembly of substantially L-shaped by fixing the said center yoke and first side yoke, The second side yoke piece having a plurality of permanent magnets constituting the first permanent magnet row and the third side yoke piece having a plurality of permanent magnets constituting the second permanent magnet row, Next, the third side yoke piece in the opposed state is brought into contact with and fixed on the surface facing the magnetic air gap of the first side yoke that forms the substantially L-shaped yoke assembly. together, by fixing the second side yoke pieces of the opposite state to the center yoke that forms a yoke assembly of said substantially L-contacts, moving coil, characterized in that assembling the magnetic circuit Method of assembling a linear motor.

Images