JP4532864B2 - 3-phase linear motor - Google Patents

Description

The present invention relates to a three- phase linear motor.

  A so-called race track type as shown in FIG. 9 is known as a single coil most commonly used for constituting a linear motor. The coil 100 is manufactured by rotating around an axis passing through the center of the coil, and has a planar structure. Two straight portions (long side portions) 101 extending in the vertical direction in the figure are effective portions for generating thrust. On the other hand, the upper and lower end portions (short-side portions) only have a function of connecting the two straight portions 101 and are referred to as short-side portions 102. The distance between the centers of the two straight portions 101 is Lc.

  FIG. 10 shows a basic configuration when a voice coil motor or a three-phase synchronous linear motor is configured using a racetrack type coil as shown in FIG. In FIG. 10, the case where the racetrack type coil as described in FIG. 9 is used as the voice coil 200 and the case where the same three racetrack type coils are combined and used as the three-phase coil 300 are shown in the form of a plan view. Yes. The voice coil 200 and the three-phase coil 300 are accommodated in the space indicated as the coil installation space in the figure, but in FIG. 10, the voice coil 200 and the three-phase coil 300 are shown on the outside for convenience.

  The magnet device of the linear motor is formed by arranging a plurality of permanent magnets 210 with a coil installation space extending in one axis direction in between. In particular, the magnetic poles of the opposing permanent magnets 210 are different from each other, and the magnetic poles of the adjacent permanent magnets 210 are also different from each other. As a result, a strong magnetic flux density is generated in the gap serving as the coil installation space. The distance from the N pole center of a certain permanent magnet 210 to the S pole center of the adjacent permanent magnet 210 is called a magnetic pole pitch. FIG. 10 shows a phase display in which one N-pole center is the origin and coordinates along the magnet row are normalized by the magnetic pole pitch. In FIG. 10, the magnetic pole pitch is π (rad), and the magnetic period length from one N-pole center to the next N-pole center is 2π (rad). At this time, the magnetic flux density along the coordinates is approximately represented by A cos θ, where A is the maximum value.

  In FIG. 10, the voice coil motor has a center-to-center distance Lc between two coil straight portions equal to the magnetic pole pitch π, and each of the two coil straight portions is adjacent to the centers of the N and S poles of the adjacent permanent magnet 210. The motors are arranged so as to match. That is, FIG. 10 shows a large number of pairs of permanent magnets 210 facing each other, but in the case of a voice coil motor, the permanent magnet side is composed of at least two pairs of permanent magnets 210. In the two linear portions of the voice coil 200, the current and magnetic flux have opposite directions, but the thrust generated by the vector product is in the same direction. Since the voice coil 200 is installed at the maximum point of the magnetic flux density, the generated thrust is also maximized. However, the stroke cannot be made large.

  As described in FIG. 9, in the case of the racetrack type coil 100, only the straight portion 101 contributes to generate thrust, and the upper and lower short sides 102 are not related. The short side portion 102 generates a side force perpendicular to the propulsion direction when entering the magnet row shown in FIG. 10, so it must be removed from the magnet row. The width of the short side portion 102 (the size in the vertical direction in the figure) is basically the same as the width of the straight portion 101 (the size in the horizontal direction in the drawing). The problem is that the storage property of 102 is poor.

  On the other hand, in the case of the three-phase synchronous linear motor in FIG. 10, three coils 300U, 300W, and 300V are integrated in two magnetic periods (4π (rad)) in the order of U phase, W phase, and V phase. Deploy. When the current is adjusted to flow in each coil so as to synchronize with the magnetic phase, even if the three-phase coil 300 moves, a substantially constant thrust can be obtained regardless of its position.

  As apparent from FIG. 10, in the three-phase coil 300, the linear portions of the coils in adjacent phases interfere with each other, so that the width of the linear portion of the coil is actually only half that of the voice coil 200. Accordingly, the width of the short side portion is also half that of the voice coil 200, but the storage property of this portion also becomes a problem.

  As a method for solving the problem of the short side in the racetrack coil as described above, a so-called saddle coil as shown in FIG. 11 has been proposed. The saddle type coil 400 has a shape in which the short side portion 102 of the racetrack type coil 100 shown in FIG. An example of a method for manufacturing the saddle coil 400 will be described below.

  In FIG. 11A, a winding having a rectangular cross section having a width t is wound as a race track type by winding a predetermined number of times on the same plane. This one-layer coil has a winding start end 100s on the innermost side and a winding end end 100e on the outermost side. Next, in order to make a coil for one phase, the coil for one layer shown in FIG. 11A is bent approximately 90 degrees so that the main surfaces of the two linear portions 101 face each other. It is formed into a letter shape.

  In FIG. 11 (b), a plurality of substantially U-shaped shapes are prepared as described above, and a plurality of these are stacked to form a saddle coil 400 for one phase. Due to such lamination, in the above folding process, the interval between the two linear portions of the innermost coil is the smallest and the interval between the two linear portions of the outermost coil is the largest. Needless to say. Hereinafter, the left and right long side portions are referred to as a straight line portion 401, and the upper and lower short side portions are referred to as a folded portion 402. Of course, the above-described saddle coil manufacturing method is merely an example. In short, the short side of the substantially long rectangular coil is a folded portion that forms an angle of about 90 degrees with respect to the straight portion on the long side. Anything that is made in is good.

Furthermore, a coil as shown in FIG. 12 in which two saddle coils as shown in FIG. 11 are combined has been proposed as a connected saddle coil 500. In FIG. 12, two saddle coils 400A and 400B are combined such that the folded portions 402A and 402B are opposite to each other and the two sets of linear portions 401A and 401B are in close contact with each other. Then, currents in the same direction are allowed to flow through the linear portions 401A and 401B that are in close contact with each other. As a result, a coil is obtained in which the linear portions 401A and 401B that are brought into close contact with each other are integrated (see, for example, Patent Documents 1 and 2).
JP 2002-95231 A JP 2001-103725 A

An object of the present invention is to provide a three- phase linear motor that is effective in reducing the heat generation of a coil by using the above-described connecting saddle type coil.

The present invention is also to realize a number of wires reduction of between switching boxes and coils for switching a current flowing through the coil in the upper Symbol 3-phase linear motor.

According to the present invention, a plurality of pairs of permanent magnets with different magnetic poles facing each other with a coil installation space in which a three-phase coil is disposed are arranged at a magnetic pole pitch π (rad) in the moving direction of the movable part. In the three-phase linear motor in which the magnetic poles of the adjacent permanent magnets are also different with respect to the moving direction, the coils of each phase in the three-phase coil are straight lines in which the short side of the substantially long rectangular coil is the long side. It is composed of two saddle-shaped coils which are folded portions that form an angle of about 90 degrees with respect to the portions, and these two saddle-shaped coils are arranged so that the two folded portions in the respective saddle-shaped coils are opposite to each other. And two linear portions between the two folded portions of one saddle coil are respectively connected to the two folded portions of the other saddle coil. Of close contact as the adhesion straight section into two straight portions, the one of the straight portions of the two straight portions of the one saddle coil also in close contact with the two folded portions of the other saddle coil, And, one of the two straight portions of the other saddle coil is combined as a connecting saddle coil so as to be in close contact with the two folded portions of the one saddle coil, In addition, the three-phase coil is in close contact with the outside of one tight linear portion of the first phase connected saddle coil and the outside of one tight linear portion of the second phase connected saddle coil. The outer side of the other close contact linear part of the connected saddle type coil of the third phase and the outer side of one close contact linear part of the third phase connected saddle type coil are integrally arranged so as to be aligned in a uniaxial direction. In addition, each connecting saddle coil is on the outer side of one of the close contact linear portions. Alternatively, the distance between the inner side and the inner side or the outer side of the other contact straight line portion is equal to the distance between the magnetic pole centers of two adjacent permanent magnets in the movement direction, and the pitch of one phase of the three-phase coil is The extension length per unit of the three-phase coil is 4π (rad) at 4π / 3 (rad), so that a space is created between the inner side of the one close contact straight line portion and the inner side of the other close contact straight line portion. There is provided a three-phase linear motor characterized in that the connecting saddle type coil is accommodated in a cooling shell capable of circulating a refrigerant and a reinforcement is incorporated in the space.

  Also in this three-phase linear motor, currents in opposite directions are passed through the two contact linear portions of each phase.

  In the present three-phase linear motor, the coil of each phase is a distance between the outer side or the inner side of one of the two contact linear portions and the inner side or the outer side of the other contact linear portion. Is made equal to the distance between the magnetic pole centers of two permanent magnets adjacent to each other in the moving direction.

3-phase linear motor that by the present invention, by using a connecting saddle coil is effective in reducing the heat generation of the coil, the number of wiring lines between the switching box and the coil for switching a current flowing through the coil Can be reduced. Further, when the connecting saddle type coil is accommodated in the cooling shell and used in a reduced pressure atmosphere, it is possible to easily realize the reinforcement that suppresses the expansion of the cooling shell due to the pressure difference between the inside and outside of the cooling shell.

  FIG. 1 shows a voice coil motor and a three-phase linear motor according to the present invention in the form of a plan view similar to FIG. In the case of a magnet device for a voice coil motor, at least two pairs of permanent magnets 11 are arranged with a coil installation space extending in one axial direction in between. On the other hand, the magnet device in the case of a three-phase linear motor is formed by arranging a plurality of pairs of permanent magnets 11 with a coil installation space extending in one axial direction. In particular, the magnetic poles of the permanent magnets 11 facing each other are different from each other, and the magnetic poles of the adjacent permanent magnets 11 are also different from each other. As a result, a strong magnetic flux density is generated in the gap serving as the coil installation space.

  In this embodiment, the connecting saddle coil described above is used as the coil. In particular, the connecting saddle coil 50 for the voice coil motor is connected to the connecting saddle coil 50 having a wide linear portion as described later. Used as a coil. On the other hand, as will be described later, a connecting saddle coil having a narrow straight portion is used for the connecting saddle coil for the three-phase linear motor.

  Also in this embodiment, the distance from the N pole center of a certain permanent magnet 11 to the S pole center of the adjacent permanent magnet 11 is referred to as a magnetic pole pitch p, and the coordinates along the magnet row with one N pole center as the origin. Is normalized by the magnetic pole pitch p and displayed as a phase as shown in FIG. That is, the magnetic pole pitch p is π (rad), and the magnetic period length from one N-pole center to the next N-pole center is 2π (rad). At this time, as described with reference to FIG. 10, the magnetic flux density along the coordinates is approximately represented by Acos θ, where A is the maximum value.

  In FIG. 1, regarding the voice coil motor, the voice coil 200 described with reference to FIG. 10 is replaced with a connected saddle coil 50 including two saddle coils. In this voice coil motor, the distance Lp between the portions where the linear portions are in close contact with each other in the two saddle coils is equal to the magnetic pole pitch p, and the portions where the linear portions are in close contact with each other are adjacent to the permanent magnet 11. The motor is arranged so as to coincide with the centers of the north and south poles. Hereinafter, a straight line portion formed by closely contacting two straight line portions is referred to as a close contact straight line portion. Of course, they are connected so that the current direction of the contact straight line portions is the same. In addition, the direction of the current in one contact straight line portion is opposite to the direction of the current in the other contact straight line portion, and the magnetic flux has the opposite direction, but the thrust generated by the vector product is the same direction. Since the connecting saddle coil 50 is installed at the maximum point of the magnetic flux density, the generated thrust is also maximized.

  On the other hand, in the case of a three-phase linear motor, the three racetrack type coils 300U, 300W, and 300V described in FIG. 10 are replaced with three connected saddle type coils 60U, 60W, and 60V composed of two saddle type coils. . In other words, three linked saddle-shaped coils 60U, 60W, 60V are arranged in an integrated manner between two magnetic periods (4π (rad)) in the order of U phase, W phase, and V phase. In other words, the three connecting saddle coils 60U, 60W, 60V are in close contact with the outside of one contact straight portion of the connecting saddle coil 60U and the outside of one contact straight portion of the connecting saddle coil 60W. The outside of the other close contact linear part of the coil 60W and the outside of the close contact linear part of the connecting saddle type coil 60V are in close contact with each other so as to be aligned in a uniaxial direction. In addition, with regard to the connecting saddle type coil 60U, the distance between the outside (or inside) of one contact straight line portion and the inside (or outside) of the other contact straight line portion is the distance Lp, that is, the magnetic pole pitch p. To be equal to The same applies to the connecting saddle coils 60W and 60V.

  In such a three-phase coil, if the current is adjusted to flow in each phase coil so as to be synchronized with the magnetic phase, even if the three-phase coil moves, a substantially constant thrust is generated regardless of its position. can get.

  Next, a connecting saddle type coil used in a voice coil motor or a three-phase linear motor according to the present invention will be described with reference to FIGS. Both FIG. 2 and FIG. 3 show a connecting saddle type coil formed by connecting two saddle type coils obtained by attaching a folded portion to a racetrack type coil.

  The connection saddle coil 50 of FIG. 2 shows an example in which two saddle coils 50A and 50B formed by racetrack coils having two wide straight portions are combined as described in FIG. Such a connecting saddle coil 50 is suitable for a voice coil motor, but can also be applied to a three-phase linear motor. In addition, the part shown with the broken line shows the outline before folding.

  The connection saddle coil 60 of FIG. 3 shows an example in which two saddle coils 60A and 60B made up of racetrack coils having two narrow linear portions are combined as described in FIG. Such a connecting saddle coil 60 is suitable for a three-phase linear motor. This is because the linear portions of the coils in adjacent phases interfere with each other as described above. However, it may be applied to a voice coil motor.

  In the connecting saddle-type coil 50 as shown in FIG. 2, the width, thickness and height of the straight portions related to the thrust generation in the saddle-type coils 50A and 50B are the same. In the racetrack type coil, it extends up and down by the width of the folded portion (size in the vertical direction), but in the structure of the connecting saddle type coil, this is distributed to the left and right. The choice of whether to extend vertically or to distribute to left and right depends on the type of usage and cannot be generally stated. However, for example, when used in the form as shown in FIG.

  FIG. 4A shows a vertical cross-sectional structure when a connecting saddle type coil is applied to a linear motor called a movable coil type. 2 and 3 can be used as the connection saddle coil, but the case where the connection saddle coil 60 of FIG. 3 is used will be described below. In FIG. 4A, a plurality of permanent magnets 41 are fixed to an inner wall of a substantially U-shaped yoke 40 that is fixed to a fixing portion (not shown) and extends in a uniaxial direction in the form described in FIG. In the coil installation space formed between the permanent magnets 41 on both sides, the three-phase coils 60U, 60W, 60V shown in FIG. 1 are movably disposed. In FIG. 4 (a), one connecting saddle coil is indicated by 60. On the other hand, the holder 42 is attached to the upper folded portion side of the connecting saddle type coil 60 here. The holder 42 is supported so as to be movable in the uniaxial direction via a guide member (not shown) extending in the uniaxial direction. The holder 42 is also usually provided with a table for loading an object to be conveyed.

  FIG. 4B shows a vertical cross-sectional structure in the case where a connecting saddle type coil is applied to a linear motor called a movable magnet type. In FIG. 4B, a large number of three-phase coils composed of the three connecting saddle-shaped coils 60U, 60W, 60V shown in FIG. 1 are arranged in a uniaxial direction in series, and both ends thereof are fixed by fixing portions. The In FIG. 4 (b), one connecting saddle coil is indicated by 60. A yoke 45 having a square cross section is disposed so as to be movable in a uniaxial direction so as to surround the periphery of the connection saddle coil 60. That is, the yoke 45 has a predetermined length and is supported so as to be movable in the uniaxial direction via a guide member (not shown) extending in the uniaxial direction. A plurality of permanent magnets 46 are fixed to both inner side walls of the yoke 45, respectively.

  In either case of FIGS. 4A and 4B, permanent magnets enter both sides of the linear contact portion of the connecting saddle coil 60, so that there is an appropriate space for storing the folded portion above and below the permanent magnet. to be born. On the other hand, when a race track type coil is used, it becomes longer in the vertical direction, and useless spaces are created above and below the permanent magnet.

  In the case of a voice coil motor, the form is the same as in FIGS. 4 (a) and 4 (b). That is, in the case of the movable coil type, the connecting saddle type coil 50 shown in FIG. 1, that is, the voice coil, is movably disposed in the coil installation space formed between the permanent magnets 41 on both sides. On the other hand, in the case of the movable magnet type, a large number of connecting saddle type coils 50 shown in FIG. 1 are arranged in series in a uniaxial direction, and both end portions thereof are fixed by fixed portions.

  The voice coil 200 shown in FIG. 10 and the connecting saddle type coil 50 (voice coil) shown in FIG. 1 take the maximum value of thrust at the illustrated position (θ = 0 rad). As the voice coil moves, the thrust decreases as shown in FIG. In general, it is desirable for a voice coil to continue to produce a constant thrust regardless of position variations. For example, θ can only be up to 0.45 (rad) for a request to suppress the thrust drop to within 10%. Since the normalized coordinate is π (rad) when the magnetic pole pitch is p (mm), the stroke L (mm) corresponding to 0.45 (rad) is L = (0.45 / π) p ( mm).

  In order to increase the stroke L, the magnetic pole pitch p must be increased. On the other hand, when the magnetic pole pitch p is increased with a racetrack coil having a wide linear portion, the width of the upper and lower short sides (size in the vertical direction) is increased and the storage property is deteriorated as described above. It is. Therefore, it becomes clear that the superiority of the connecting saddle type coil (voice coil) 50 according to the present invention increases as the large stroke L is required.

  However, the racetrack type coil is also devised to divide the coil into two and keep the width of the upper and lower short sides small. For example, instead of the voice coil 200 of FIG. 10, it is conceivable to use two race track type voice coils 200A and 200B as shown in FIG. In this case, the width of the short side portion can be halved while keeping the volume of the straight portion effective for thrust generation the same as that of the voice coil of FIG. 10 or FIG. Further, the magnetic flux density from the north pole to the south pole of the central permanent magnet 215 can be similarly taken. However, the magnetic flux density of the permanent magnet 216 having a half length disposed on both sides of the permanent magnet 215 is considerably lower than the central magnetic flux density.

  Therefore, in the case of the voice coil motor shown in FIG. 6, the thrust is generally inferior, and the thrust reduction rate with respect to voice coil position fluctuation is also large. In addition, there is a burden that permanent magnets 215 and 216 of different sizes must be made. Therefore, it can be said that the voice coil motor by the connecting saddle type coil 50 as in the present invention aims at the same effect as the voice coil motor of FIG. 6, but far superior in performance.

  In order to explain the superiority of the three-phase linear motor according to the present invention, the three-phase linear motor disclosed in Patent Document 2 will be described with reference to FIG. FIG. 7 shows a three-phase linear motor using a connecting saddle type coil in the form of a plan view similar to FIG.

  7, in this example, the six saddle coils described in FIG. 11 are integrated in a uniaxial direction as follows. The inside of one linear part of the V-phase first saddle coil 71-1V with the folded part reversed is adjacent to the inside of one linear part of the U-phase first saddle coil 71-1U. Arrange. Adjacent to the outside of one straight line portion of the U-phase first saddle coil 71-1U is the outside of one straight line portion of the W-phase first saddle coil 71-1W having the same folded portion. Let them be arranged. The W-phase first saddle coil 71-1W is disposed so that the inside of the other straight line portion of the V-phase first saddle coil 71-1V is adjacent to the inside of one straight line portion of the W-phase first saddle coil 71-1W. Between the inner side of the other straight line portion of the W-phase first saddle coil 71-1W and the outer side of the other straight line portion of the V-phase first saddle coil 71-1V, the folded portion is reversed. One linear portion of the U-phase second saddle coil 71-2U is arranged adjacent to each other. Between the outer side of the other straight line portion of the W-phase first saddle coil 71-1W and the inner side of the other straight line portion of the U-phase second saddle coil 71-2U, the folded portion is oriented in the same direction. One linear portion of the V-shaped second saddle coil 71-2V is arranged adjacent to each other. Between the outside of the other straight line portion of the U-phase second saddle coil 71-2U and the inside of the other straight line portion of the V-phase second saddle coil 71-2V, the folded portion is reversed. The W-phase second saddle coil 71-2W is arranged so that one linear portion is adjacent. The distance from the inner side of one linear part of the saddle coil to the outer side of the other linear part is made equal to the magnetic pole pitch π.

  Here, the three-phase coil in FIG. 10 or FIG. 1 has a normalized length of 4π and one unit of the three-phase coil is mounted, whereas in the three-phase coil in FIG. 7, (4 + 2/3) π is 2 The unit is implemented. Since the volume of the linear portion for each unit is the same, it can be said that the three-phase coil using the saddle type coil can mount a coil turn number close to twice that of the racetrack type coil per unit length. When the same current flows, the thrust is approximately doubled and the heat generation amount is approximately doubled in the three-phase coil of FIG.

  On the other hand, if an attempt is made to obtain a double thrust with a racetrack coil, the amount of heat generation is quadrupled by doubling the current. Therefore, the three-phase coil in FIG. 7 generates about half the heat to generate the same thrust.

  From the viewpoint of the amount of generated heat alone, the three-phase coil in FIG. 7 is superior, so the three-phase coil in FIG. 1 may seem unnecessary. However, in practice, the three-phase coil of FIG. For example, the moving magnet type linear motor requires a very long stroke. In this case, in order to suppress heat generation, it is necessary to connect each coil to a switching box having a large number of changeover switches, and to switch the coil through which a current flows as the mover (three-phase coil) moves by the changeover switch. become.

  However, since the number of coils in the three-phase coil in FIG. 7 is approximately doubled, the number of wires connecting the switching box and each coil is also doubled. Since three wires are required for each coil unit, for example, when it exceeds 10 units, it becomes 30 or more and it becomes difficult. On the other hand, in the case of the present invention, since the number of wirings is half, it becomes easy.

  FIG. 8 is a longitudinal sectional view for explaining a coil cooling system applied to the movable coil linear motor. The saddle-shaped connecting coil 60 is accommodated in a cooling shell 80 having a larger cross-sectional shape. In the cooling shell 80, the liquid refrigerant can be circulated, and the upper liquid reservoir portion 81 is provided at a position corresponding to the upper folded portion of the vertical connection coil 60, and the lower folded portion is disposed on the lower vertical connection coil 60. A corresponding portion has a lower liquid reservoir 82. 83 is a coil holder. The illustration of the stator side of the linear motor is omitted.

  When a linear motor with a cooling shell as shown in FIG. 8 is used in a vacuum, the pressure difference between the inside and outside of the cooling shell 80 increases, so it is desirable to add reinforcement that restricts the expansion of the cooling shell 80. .

  In the three-phase coil shown in FIG. 7, there is no space for reinforcement because the windings are almost completely packed. On the other hand, the three-phase coil according to the present invention shown in FIG. 1 has a large space in the central portion of the coil as can be seen from FIG. Therefore, the three-phase motor according to the present invention is more convenient.

3-phase linear motor that by the present invention, a stage device and for fine movement of the driven object, a semiconductor manufacturing device, it can be applied to the stepper or the like for such exposure apparatus.

It is a top view for demonstrating the relationship between the permanent magnet and coil in the voice coil motor and three-phase linear motor by this invention using a connection saddle-type coil. It is the figure which showed an example of the connection saddle type coil used for the voice coil motor by this invention. It is the figure which showed an example of the connection saddle type coil used for the three-phase linear motor by this invention. FIG. 2 is a longitudinal sectional view when the voice coil motor or the three-phase linear motor shown in FIG. 1 is configured as a moving coil type motor (FIG. A) and a moving magnet type motor (FIG. B). It is the figure which showed an example of the displacement amount-thrust characteristic in the voice coil motor shown by FIG. It is the top view which showed an example of the voice coil motor using the well-known race track type coil for the comparison with the voice coil motor shown by FIG. It is the top view which showed an example of the three-phase linear motor using the well-known saddle type coil for the comparison with the three-phase linear motor shown by FIG. It is a longitudinal cross-sectional view which shows schematic structure in the case of accommodating and using the voice coil or three-phase coil used in this invention in the shell for cooling. It is the perspective view which showed an example of the race track type coil. It is a top view for demonstrating the relationship between the permanent magnet and coil in a well-known voice coil motor and a three-phase linear motor. It is a figure for demonstrating an example of the manufacturing process of the saddle type coil used in this invention. It is the figure which showed the example of the connection saddle type coil which connected the saddle type coil by FIG.

Explanation of symbols

11, 41, 46, 75, 210, 215, 216 Permanent magnet 40, 45 Yoke 42, 83 Holder 50, 60, 500 Linked saddle coil 50A, 50B, 60A, 60B, 400A, 400B saddle coil 80 Cooling shell 100, 200A, 200B Race track type coil 101, 401A, 401B Linear portion 102, 402A, 402B Turned portion 200 Voice coil 300 Three-phase coil

Claims (2)

A plurality of pairs of permanent magnets with different magnetic poles facing each other across a coil installation space in which a three-phase coil is disposed are arranged at a magnetic pole pitch π (rad) in the moving direction of the movable part, and are adjacent to each other in the moving direction. In a three-phase linear motor in which the magnetic poles of the permanent magnets are also different,
The coils of each phase in the three-phase coil are composed of two saddle-shaped coils in which the short side of the substantially long rectangular coil is a folded part that forms an angle of about 90 degrees with respect to the straight part on the long side. These two saddle coils are combined so that the two folded portions in the respective saddle coils are opposite to each other, and the two linear portions between the two folded portions in one saddle coil are Each of the two saddle coils is in close contact with two linear portions between the two folded portions as a tight linear portion, and one of the two linear portions of the one saddle coil is the other linear portion. The two folded portions of the other saddle coil, and one of the two straight portions of the other saddle coil is the two folded portions of the one saddle coil. Connected and combined into a saddle coil, moreover the three phase coils to also close contact, the outer of the one contact linear portion connecting saddle coils of the first phase coupling saddle coils of the second phase The outside of one of the contact linear portions is in close contact, and the outside of the other contact linear portion of the second phase connected saddle coil and the outside of the one contact linear portion of the third phase connected saddle coil are The connecting saddle coils are arranged so as to be aligned in a uniaxial direction while being in close contact with each other, and the distance between the outer side or the inner side of one of the close contact linear portions and the inner side or the outer side of the other close contact linear portion Is equal to the distance between the magnetic pole centers of two permanent magnets adjacent to each other in the moving direction, and the one-phase pitch of the three-phase coil is 4π / 3 (rad), and the extension length per unit of the three-phase coil is 4π (rad) and the one contact straight line portion A space is formed between the inner side of the inner wall and the inner side of the other contact straight line portion, and the connecting saddle coil is accommodated in a cooling shell capable of circulating the refrigerant, and reinforcement is incorporated in the space. A three-phase linear motor characterized by that.   2. The three-phase linear motor according to claim 1, wherein currents in opposite directions are passed through the two contact linear portions of each phase. 3.

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