KR102339956B1 - linear motor - Google Patents

Abstract

To provide a linear motor capable of significantly reducing a suction force and reducing a detent force while achieving a compact configuration and generation of a large thrust. A linear motor includes a mover having a magnet arrangement in which a plurality of rectangular permanent magnets are arranged, a back yoke as a stator which is disposed to face the mover at intervals, and a back yoke as a stator opposite to the back yoke at a distance from the mover An armature as an arranged stator is provided, the magnetization direction of each of the plurality of permanent magnets is in the thickness direction, the magnetization directions of adjacent permanent magnets are opposite to each other, and the armature includes a plurality of permanent magnets each having a driving coil wound thereon The magnetic pole teeth are at equal pitch, and the back yoke has a plurality of magnetic pole values at the same position as the magnetic pole values of the armature on the surface opposite to the mover in the moving direction of the mover.

Description

linear motor

The present invention relates to a linear motor that takes out a linear motion output by combining a mover and a stator.

Conventionally, a method of converting the output of a rotary motor into linear motion with a ball screw has been used for X and Y movement. However, since the moving speed is slow, the use of a linear motor capable of directly taking out the linear motion output is progressing. A linear motor is generally constituted by combining a mover having a plurality of rectangular permanent magnets and an armature having a plurality of magnetic pole teeth.

In addition, since high-speed repetitive motion is required for wire bonding and tip mounters in a processing machine of a semiconductor manufacturing apparatus, it is preferable to use a linear motor having a small mass and high acceleration. In order to reduce the size of such a linear motor, for example, as disclosed in Patent Documents 1 or 2, the permanent magnets of the mover do not face the front surface of the armature as a stator, but the length of the arrangement of permanent magnets in the mover is increased. A linear motor configured to be shorter than the length of the armature is employed.

This type of linear motor includes a mover having a magnet array in which a plurality of permanent magnets are arranged, a flat plate-shaped back yoke integrated into the magnet array, and an armature in which a driving coil is wound on each of a plurality of magnetic pole teeth. It forms a configuration in which the are opposed at a distance. By energizing the drive coil, the mover (magnet arrangement and back yoke) moves, and the difference in length between the mover and the armature becomes the operable stroke of the linear motor.

When the movable element is formed of a back yoke formed of a ferromagnetic material and a magnet arrangement, an attractive force is generated between the opposing stator and the back yoke. Due to the generated suction force, a large normal drag force acts on the bearing supporting the movable member to be movable in a predetermined direction. This normal drag force shortens the life of the bearing. In addition, the direction in which the normal drag force acts is a direction intersecting the moving direction of the movable element. Therefore, it is necessary to select a bearing in consideration of the normal drag. Therefore, a large bearing is selected rather than a bearing based on the load by the mover. This leads to an enlargement of the overall linear motor.

Then, unlike the above-mentioned linear motor, a linear motor in which only a magnet arrangement functions as a mover and a back yoke functions as a stator has been proposed (Patent Documents 3 to 5 and the like).

In this type of linear motor, the magnet arrangement and the flat back yoke are separated, the back yoke is opposed to the magnet arrangement at a distance from the side opposite to the armature, and only the magnet arrangement is movable. Only the magnet arrangement moves, the back yoke does not move the same as the armature. The length of the magnet arrangement is shorter than the length of the armature, and the difference in this length becomes the operable stroke of the linear motor.

Japanese Patent Laid-Open No. 2005-269822 Japanese Patent Republished Patent Publication No. WO2016/159034 Japanese Patent Laid-Open No. 2005-117856 Japanese Patent Laid-Open No. 2015-130754 Japanese Patent Laid-Open No. 2005-184984

The mover is strongly attracted to the magnetic pole tooth surfaces of the opposing armature. The attraction|suction force F at this time is represented by a following formula.

F=B2S/2μ0

(However, B: magnetic flux density on the magnetic pole value of the electrode element, S: the effective area of the mover and the armature opposite, μ0: the magnetic permeability of the vacuum)

In a linear motor (integrated linear motor: Patent Documents 1 or 2, etc.) having a movable element in which a magnet arrangement and a flat-type back yoke are integrated, this attraction force is usually 10 times or more of the rated thrust. Therefore, there is a problem in that the movable member is bent by the large suction force. As a result, the dimensional accuracy of a processing machine using a linear motor in which such warpage occurs is deteriorated. In addition, it is necessary to increase the rigidity of the movable member, and there is a difficulty in that the structure is enlarged.

Since the excessive suction force also extends to the linear guide supporting the movable element, the linear guide needs to have a large rated load so as to withstand this excessive suction force. Therefore, it is preferable to reduce the suction force as described above. However, when reducing the suction force, it is necessary to realize both a compact configuration and a large thrust force.

In addition, in the integrated linear motor, there is a problem that the cogging torque becomes large due to the large edge effect, and the detent force is large.

In a linear motor (separate type linear motor: Patent Documents 3 to 5, etc.) configured to move only the magnet array by separating the magnet array and the flat-type back yoke, the magnet array acts as a suction force from both the back yoke and the armature, Compared with the integrated linear motor, the overall suction force is small. However, in the separation type linear motor, the area of the magnetic pole opposite to the magnet arrangement is only the area of the magnetic pole value opposite on the armature side, whereas on the back yoke side, the area is substantially the same as the area of the electromagnet. Therefore, when the magnetic flux densities within both intervals are the same, a larger attractive force acts on the back yoke side according to the ratio of the magnetic pole area, so a significant reduction in the overall attractive force cannot be expected.

Therefore, it is conceivable to increase the distance between the magnet arrangement and the back yoke to decrease the magnetic flux density of the gap, and to reduce the attraction force between the magnet arrangement and the back yoke to the same extent as the attraction force between the magnet arrangement and the armature. However, when the distance between the magnet arrangement and the back yoke is increased, since the magnetic flux density for generating thrust from the armature also decreases, there is a problem that the thrust becomes small. Accordingly, in the separation type linear motors proposed so far, there is a problem that a decrease in thrust is unavoidable in order to reduce the suction force acting on the mover.

Further, in the separation type linear motor, as described above, the attractive force between the mover (magnet arrangement) and the stator (armature) and the attractive force between the mover and the back yoke are approximately equal in magnitude and opposite to each other. It becomes possible to reduce the suction force which acts. However, by separating the back yoke and the magnet arrangement, it becomes clear that the eddy current generated in the back yoke during operation increases. An increase in the eddy current leads to heat generation. Such a linear motor is not suitable as a driving source of a stage in an apparatus that needs to maintain the environmental temperature in a predetermined range, for example, a semiconductor manufacturing apparatus.

The present invention was made in view of such circumstances, and while achieving a compact configuration and generation of a large thrust, it is possible to significantly reduce the suction force and at the same time to provide a linear motor capable of reducing the detent force. do.

Another object of the present invention is to provide a linear motor capable of suppressing eddy currents while reducing the attraction force acting on the magnet arrangement.

A linear motor according to the present invention includes a mover having a magnet arrangement in which a plurality of rectangular permanent magnets are arranged, a back yoke serving as a stator disposed to face the mover at a distance from the mover, and the back yoke being spaced apart from the mover. An armature as a stator disposed opposite to the yoke is provided, the magnetization direction of each of the plurality of permanent magnets is in the thickness direction, the magnetization directions of adjacent permanent magnets are opposite to each other, and the armature comprises: Each of the plurality of magnetic pole values on which the driving coil is wound has an equal pitch, and the back yoke has a plurality of magnetic pole values at the same position as the magnetic pole values of the armature on a surface opposite to the mover in the moving direction of the mover. and the magnetic pole area of the magnetic pole value in the back yoke is 0.9 to 1.1 times the magnetic pole area of the magnetic pole value in the armature, and the distance between the mover and the back yoke is the same as the distance between the mover and the armature or characterized by being large.

In the linear motor of the present invention, a mover having a magnet arrangement in which a plurality of permanent magnets are arranged, a back yoke arranged to face the mover at a distance from the mover, and an opposite arrangement to the mover at a distance from the back yoke It has one armature. The magnet arrangement functions as a mover, and the back yoke and armature function as a stator. Each of the plurality of rectangular permanent magnets in the magnet arrangement is magnetized in the thickness direction, and the magnetization direction between the adjacent permanent magnets is in the opposite direction. The armature has a plurality of magnetic pole values at equal pitches, and a drive coil is wound around each magnetic pole value. In the back yoke, the surface facing the movable element is not flat, and a plurality of magnetic pole teeth are formed at equal pitches. The pitch of the magnetic pole values in the back yoke is the same as the pitch of the magnetic pole values of the armature, and the position of the magnetic pole values in the back yoke is the same as the magnetic pole values of the armature in the moving direction of the mover (linear motor). In addition, the magnetic pole area of the magnetic pole value of the back yoke is 0.9 to 1.1 times the magnetic pole area of the magnetic pole value of the armature. Further, the distance between the mover and the back yoke is greater than or equal to the distance between the mover and the armature.

In the linear motor of the present invention, magnetic pole values having substantially the same magnetic pole area are provided in the back yoke at the same position as the armature. That is, only the part of the back yoke to which the driving magnetic flux from the armature is applied is brought close to the mover, and a space is provided from the mover other than the part opposing the magnetic pole value of the armature. Since the magnetic pole area of the armature facing the mover and the magnetic pole area of the back yoke facing the mover are approximately equal, they effectively cancel each other out, and the overall attractive force is greatly reduced. Accordingly, it is possible to realize a significant reduction in the suction force without increasing the distance between the mover and the back yoke. At this time, since it is not necessary to increase the distance between the mover and the back yoke, the decrease in thrust is small.

In addition, since a shear region of the driving magnetic flux is generated in the back yoke due to the concavo-convex shape due to the formation of magnetic pole values in the back yoke, not only the armature but also the back yoke contribute to the generation of thrust. This thrust generation compensates for the drop in thrust caused by an increase in the spacing (air gap) between the movable elements in two places, and thus a large thrust can be obtained as a whole. Accordingly, it is possible to significantly reduce the attraction force acting on the magnet arrangement (movable element) while maintaining the large thrust force.

In the linear motor of the present invention, since the mover is arranged between the armature having a plurality of magnetic pole values at equal pitch and a back yoke having a plurality of magnetic pole values at the same position as the magnetic pole values of the armature in the movable direction, the movable element is perpendicular to the movable direction. Since cogging of the magnet arrangement in the in-direction is reduced, it is possible to reduce the mover detent force.

If the magnetic pole area of the magnetic pole value of the back yoke is made too wide, a large amount of magnetic flux is picked up from the surroundings to increase the suction power. lowers Accordingly, the magnetic pole area of the magnetic pole value of the back yoke is 0.9 to 1.1 times the magnetic pole area of the magnetic pole value of the armature.

Since the driving coil is wound around the magnetic pole value of the armature, the magnetic pole value of the armature is not configured to be too low, and the height of the magnetic pole value of the armature becomes higher than the height of the magnetic pole value in the back yoke. For this reason, in the back yoke, since the height of the magnetic pole value is low, magnetic flux is generated in parts other than the magnetic pole value, and the attraction force tends to be larger than that on the armature side. Accordingly, the distance between the mover and the back yoke is made equal to or larger than the distance between the mover and the armature so as to effectively cancel the suction force.

The linear motor according to the present invention is characterized in that the height of the magnetic pole value in the back yoke is 1/20 times or more and 2 times or less of the pitch of the magnetic pole values.

In the linear motor of the present invention, when the height of the magnetic pole values of the back yoke is made too small compared to the pitch, the effect of providing the magnetic pole values (concave-convex shape) is not obtained. , the effect remains unchanged and goes against the miniaturization. Accordingly, the height of the magnetic pole values in the back yoke is set to be 1/20 times or more and 2 times or less of the pitch of the magnetic pole values.

The linear motor according to the present invention is characterized in that the length of the mover is shorter than the length of the armature and shorter than the length of the back yoke.

In the linear motor of the present invention, the length of the mover is shorter than the length of each of the armature and the back yoke. Therefore, it is a compact structure, and large acceleration can be ensured. Moreover, since the edge effect becomes small, the cogging torque becomes small, and reduction of a detent force can be aimed at.

The linear motor according to the present invention is characterized in that the size of the distance between the mover and the back yoke and/or the size of the distance between the mover and the armature are variable.

In the linear motor of the present invention, the size of the distance between the mover and the back yoke and/or the size of the distance between the mover and the armature is variable. Accordingly, by adjusting the size of the distance between the mover and the back yoke and/or the size of the distance between the mover and the armature according to the magnitude of the driving magnetomotive force during use, it is possible to make the attraction force almost zero.

A linear motor according to the present invention includes a mover having a magnet arrangement in which a plurality of rectangular permanent magnets are arranged, a back yoke serving as a stator disposed to face the mover at a distance from the mover, and the back yoke being spaced apart from the mover. An armature as a stator disposed opposite to the yoke is provided, the magnetization direction of each of the plurality of permanent magnets is in the thickness direction, the magnetization directions of adjacent permanent magnets are opposite to each other, and the armature comprises: Each of the plurality of magnetic pole teeth having a driving coil wound thereon has an equal pitch, and the back yoke has a plurality of magnetic pole values at the same position as the magnetic pole values of the armature on a surface opposite to the mover in the moving direction of the mover. and the magnetic pole teeth of the back yoke are formed by stacking a plurality of plate-like members in a direction intersecting the movable direction of the movable member.

In the linear motor of the present invention, it is possible to reduce eddy currents while reducing the suction force acting on the mover by making the magnetic pole values a layered structure.

In the linear motor according to the present invention, in the back yoke, a part of the back yoke in a direction opposite to the protruding direction of the magnetic pole teeth from the base of the magnetic pole teeth is formed by stacking a plurality of plate-like members in the stacking direction of the magnetic pole teeth, It is characterized in that the plate-shaped member constituting the lamination portion of the back yoke and the plate-shaped member constituting the magnetic pole teeth are integrated.

In the linear motor of the present invention, the back yoke can further reduce eddy currents by forming a part of the back yoke in the thickness direction from the connection portion with the magnetic pole value as a laminated structure. Moreover, since the plate-shaped member constituting the lamination portion of the back yoke and the plate-shaped member constituting the magnetic pole teeth are integrated, the number of manufacturing steps is reduced.

The linear motor according to the present invention is characterized in that the plurality of plate-shaped members are insulated on the laminated surface.

In the linear motor of this invention, since the several plate-shaped member applies the insulation process to the lamination|stacking surface, it becomes possible to further reduce an eddy current.

In the linear motor according to the present invention, the mover has a holding member for holding the magnet arrangement, and the holding member has a plurality of holes into which each of the plurality of permanent magnets is inserted. characterized in that

In the linear motor of the present invention, a magnet array (a plurality of permanent magnets) is held by a holding member. Accordingly, since the rigidity of the movable element (magnet arrangement) is increased, deformation such as bending and bending of the permanent magnet is less likely to occur, and the detent force can be reduced.

The linear motor according to the present invention is characterized in that the movable member has a plate-shaped base material to which the holding member and the plurality of permanent magnets are fixed by adhesion.

In the linear motor of the present invention, in a state in which a plurality of permanent magnets are inserted into the holes of the holding member, the magnet array (plural permanent magnets) and the holding member are adhesively fixed to the plate-shaped base material. Accordingly, it is possible to further reduce the detent force by further increasing the rigidity of the movable element (magnet arrangement), and it is possible to prevent the permanent magnet from falling off.

In the linear motor of the present invention, it is possible to significantly reduce the attractive force acting on the mover (magnet arrangement) while realizing a compact configuration and large thrust generation, and at the same time, it is possible to reduce the mover detent force. . Accordingly, it is possible to suppress deformation due to bending accompanying a large suction force, and it is possible to prevent deterioration of the dimensional accuracy of the device in which the linear motor is used. Since the suction force can be made small, it is possible to reduce the rigidity of the movable member and the rigidity of the support system supporting the movable member, and not only miniaturization can be achieved, but also the acceleration can be improved by reducing the movable mass. Further, by providing the magnetic pole structure in the back yoke, since thrust from the back yoke is added to the mover, the decrease in thrust can be minimized by providing a gap between the magnet arrangement and the back yoke.

Further, in the linear motor of the present invention, it is possible to suppress the eddy current while reducing the attraction force acting on the mover (magnet arrangement).

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the structure of the linear motor of Embodiment 1. FIG.
[ Fig. 2] Fig. 2 is a side view showing the configuration of the linear motor according to the first embodiment.
Fig. 3 is a plan view showing the configuration of a mover in the linear motor according to the first embodiment.
Fig. 4 is an exploded perspective view showing the configuration of a mover in the linear motor according to the first embodiment.
Fig. 5 is a side view showing the flow of magnetic flux in the linear motor according to the first embodiment.
[ Fig. 6] Fig. 6 is a diagram showing the side shape of the back yoke in the linear motor according to the first embodiment.
It is a top view which shows the armature raw material used for manufacture of the armature in the linear motor of Embodiment 1. FIG.
It is a figure which shows the coil of the armature in the linear motor of Embodiment 1. FIG.
[ Fig. 9A ] It is a surface view showing the configuration of the linear motor according to the first embodiment.
9B] It is a side view which shows the structure of the linear motor of Embodiment 1. FIG.
[Fig. 10] Fig. 10 is a graph showing the thrust variation with respect to the electric angle of the linear motor of an example of the first embodiment.
It is a graph which shows the thrust characteristic of the linear motor of an example of Embodiment 1. FIG.
12 is a graph showing the suction force characteristics of the linear motor of an example of the first embodiment.
[Fig. 13] Fig. 13 is a side view showing the configuration of the linear motor of the first conventional example (a structure in which a magnet arrangement and a back yoke are integrated to form a movable member).
[Fig. 14A] It is a surface view showing the configuration of the linear motor of the first conventional example.
14B] It is a side view which shows the structure of the linear motor of the 1st prior art example.
[FIG. 15] It is a side view which shows the structure of the linear motor of the 2nd prior art example (a structure which used only the magnet arrangement|sequence as a mover, and the flat-type back yoke was used as a stator).
[ Fig. 16A ] It is a surface view showing the configuration of the linear motor of the second conventional example.
[ Fig. 16B ] It is a side view showing the configuration of the linear motor of the second conventional example.
17] It is a graph which shows the average thrust in the linear motor of an example of a 1st prior art example, a 2nd prior art example, and Embodiment 1. FIG.
[Fig. 18] It is a graph which shows the average suction force in the linear motor of an example of a 1st prior art example, a 2nd prior art example, and Embodiment 1
19 is a graph showing thrust characteristics of a linear motor according to another example of the first embodiment.
[ Fig. 20 ] It is a graph showing the attractive force characteristics of the linear motor of another example of the first embodiment.
[FIG. 21] It is a graph which shows the thrust characteristic of the linear motor of still another example of Embodiment 1. FIG.
22 is a graph showing the suction force characteristics of the linear motor of still another example of the first embodiment.
23 is a perspective view showing a configuration example of the linear motor according to the second embodiment.
24 is a side view showing a configuration example of the linear motor according to the second embodiment.
Fig. 25 is a perspective view showing a configuration example of magnetic pole values included in the back yoke.
26] It is a partial perspective view which shows the structural example of the base plate contained in a back yoke.
Fig. 27 is a partial perspective view of the back yoke.
28 is a partial side view of the linear motor.
[ Fig. 29A ] It is a graph showing the joule loss of a linear motor according to the related art.
[ Fig. 29B ] It is a graph showing the joule loss of the linear motor in the basic example of the second embodiment.
Fig. 30 is a side view showing another configuration example of the back yoke.
Fig. 31 is a perspective view showing a configuration example of a magnetic pole value block.
Fig. 32 is a perspective view showing a configuration example of the base part.
33 is a partial side view of the linear motor.
[FIG. 34A] It is a graph which shows the joule loss of the linear motor in the basic example of Embodiment 2. FIG.
[FIG. 34B] It is a graph which shows the joule loss of the linear motor in the 1st modification of Embodiment 2. FIG.
Fig. 35 is a side view showing another configuration example of the back yoke.
Fig. 36A is a perspective view showing a configuration example of a magnetic pole unit.
Fig. 36B is a perspective view showing a configuration example of a magnetic pole unit.
37 is a perspective view showing a configuration example of the base part.
Fig. 38A is a side view showing another configuration example of the back yoke.
38B is a perspective view showing a configuration example of the base part.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is described in detail based on drawing which shows the embodiment.

(Embodiment 1)

1 and 2 are a perspective view and a side view showing the configuration of the linear motor 1 according to the first embodiment. 3 and 4 are a plan view and an exploded perspective view showing a configuration example of the movable element 2 in the linear motor 1 according to the first embodiment. 1 and 2, only the movable element 2 is cross-sectional in a direction parallel to the movable direction so that the arrangement of the magnet can be understood.

The linear motor 1 includes a movable element 2 , a back yoke 3 , and an armature 4 . The back yoke 3 is disposed to face the mover 2 with a gap therebetween, and the armature 4 is disposed opposite to the back yoke 3 at a distance from the mover 2 . The back yoke 3 and the armature 4 function as a stator.

As shown in FIG. 4 , the movable element 2 having a long shape includes a plurality of permanent magnets 21 , a holding frame 22 , and a fixed plate 23 . The juxtaposition direction of the plurality of permanent magnets 21 is the longitudinal direction of the movable element 2 . Each permanent magnet 21 forms a rectangular shape. Each permanent magnet 21 is, for example, an Nd-Fe-B type rare-earth magnet. Each permanent magnet 21 is magnetized in the thickness direction (up and down direction in FIG. 2 ), and the magnetization direction of the permanent magnets 21 and 21 adjacent to each other is opposite. That is, in the magnet arrangement, the permanent magnet 21 magnetized in a direction from the back yoke 3 side toward the armature 4 side, and the permanent magnet 21 magnetized in a direction from the armature 4 side toward the back yoke 3 side. Magnets 21 are alternately arranged.

As shown in FIG. 4, the holding|maintenance edge 22 has comprised the rectangular plate shape. The thickness of the holding edge 22 is smaller than the thickness of the permanent magnet 21 . A plurality of rectangular holes 221 are provided in the holding frame 22 . The holding edge 22 is made of, for example, a non-magnetic material such as SUS or aluminum. The hole 221 has a shape corresponding to the permanent magnet 21 . Each permanent magnet 21 is fitted into a hole 221 and fixed to the holding edge 22 with an adhesive. The hole 221 is provided so that each permanent magnet 21 fixed to the holding edge 22 may be arranged side by side at equal pitch. In addition, when the permanent magnet 21 is fixed to the holding edge 22, it is inserted into the hole 221 so that the magnetization direction of the permanent magnets 21 and 21 adjacent to each other may become reversed. As shown in Fig. 3, each permanent magnet 21 is skewed at an angle θ.

A plurality of permanent magnets 21 are inserted into the holes 221 of the retaining rim 22 and held, and the retaining rim 22 is fixed to the fixing plate 23 with an adhesive. Further, the bottom surface of each permanent magnet 21 is also adhered to the fixing plate 23 . The fixing plate 23 is made of non-magnetic SUS or the like. As described above, since the magnet arrangement is held by the retaining edge 22 and fixed to the fixing plate 23 by adhesion, the rigidity of the movable element 2 is high, and the permanent magnet 21 does not come off. The movable element 2 is disposed at a gap between the back yoke 3 and the armature 4 so that the fixing plate 23 faces the back yoke 3 . In addition, the fixing plate 23 is not essential, and is unnecessary when the permanent magnet 21 is sufficiently held by the holding edge 22 .

The lengths in the movable direction (left-right direction in Fig. 2) of the back yoke 3 and the armature 4 are approximately the same, and the lengths in the movable direction (left-right direction in Fig. 2) of the movable element 2 are the lengths of this bag It is shorter than the length at the yoke 3 and the armature 4 , and the difference in this length becomes the operable stroke of the linear motor 1 . With this configuration, the edge effect is reduced.

The surface on the side not facing the movable element 2 of the back yoke 3, which is made of mild steel, preferably a soft magnetic material (eg, silicon steel sheet) is flat, but the back yoke 3 is The surface on the side opposite to the movable element 2 is not flat, and a plurality of rectangular magnetic pole teeth 31 are formed at equal pitches in the movable direction. The height of each magnetic pole tooth 31 is 1/20 times or more and 2 times or less of the formation pitch of the magnetic pole teeth 31, Preferably, they are 1/10 times or more and 1 time or less. For example, the height of each magnetic pole value 31 is about half of the formation pitch of the magnetic pole teeth 31 .

In the armature 4, a plurality of rectangular magnetic pole teeth 42 made of a soft magnetic body at equal pitch in the movable direction are integrally provided on a core 41 which is a soft magnetic body, and a driving coil is provided for each magnetic pole tooth 42. (43) is wound.

The pitch of the magnetic pole values 31 in the back yoke 3 is the same as the pitch of the magnetic pole values 42 of the armature 4, and the position of each magnetic pole value 31 in the back yoke 3 is the mover 2 ) is the same as the position of each magnetic pole tooth 42 of the armature 4 in the moving direction. In addition, the shape of the magnetic pole face of the magnetic pole tooth 31 of the back yoke 3 opposite to the movable element 2 is the armature 4 ) of the magnetic pole tooth 42 has a rectangular shape of substantially the same shape as the magnetic pole surface facing the mover 2, and the magnetic pole area of the former is 0.9 to 1.1 times that of the latter. For example, the magnetic pole surface of the magnetic pole tooth 31 and the magnetic pole surface of the magnetic pole tooth 42 have the same rectangular shape and have the same area. Further, the interval between the movable element 2 and the back yoke 3 is equal to or greater than the interval between the movable element 2 and the armature 4 . For example, the interval of the latter is 0.5 mm, and the interval of the former is 0.5 mm or more. In this case, the distance between the movable element 2 and the back yoke 3 does not include the thickness of the fixing plate 23, even when the fixing plate 23 is included as a configuration, but the movable element 2 itself and the back yoke. The interval (shortest distance) of (3) is shown. In other words, the gap is a magnetic gap (magnetic gap), and it is not necessary to consider the thickness of the non-magnetic fixing plate 23 .

The linear motor 1 of Embodiment 1 has the basic structure of 7 permanent magnets 21, 6 magnetic pole teeth 31, and 7 pole 6 slots which the magnetic pole teeth 42 oppose. In the form shown in FIG. 1 and FIG. 2, it has the 14-pole 12-slot structure which doubles the basic structure.

In the linear motor 1 of the first embodiment, on the surface of the back yoke 3 on the side opposite to the mover 2, the magnetic pole teeth 42 of the armature 4 and the magnetic pole teeth 42 of the armature 4 are located at the same position in the moving direction and have substantially the same shape. A magnetic pole tooth 31 having a magnetic pole surface and having substantially the same magnetic pole area is formed. Accordingly, the magnitude of the attractive force generated between the mover 2 and the back yoke 3 and the magnitude of the attractive force generated between the movable element 2 and the armature 4 are approximately the same, as shown in FIG. Since both suction forces in the vertical direction are effectively canceled out, the suction force acting on the movable element 2 as a whole of the linear motor 1 becomes very small. As described above, in the linear motor 1 of the first embodiment, a significant reduction in the suction force can be realized without increasing the distance between the mover 2 and the back yoke 3 . Therefore, since there is no need to increase the distance between the movable element 2 and the back yoke 3, a decrease in thrust is not caused.

Moreover, in the linear motor 1 of Embodiment 1, as mentioned above, the armature 4 which has a plurality of magnetic pole values 42 at equal pitch, and the magnetic pole teeth 42 of this armature 4 and the same position in the movable direction. Since the movable element 2 is arranged between the back yoke 3 having the plurality of magnetic pole teeth 31, the cogging torque of the magnet arrangement in the direction perpendicular to the movable direction is reduced, so that the movable element 2 is It is possible to reduce the detent force of In addition, since the magnet arrangement is held by the retaining frame 22 and fixed to the fixing plate 23 by adhesion, the rigidity of the movable element 2 can be increased, so that the permanent magnet 21 is bent and bent. The deformation of the back is less likely to occur, and this also contributes to the reduction of the detent force of the movable element 2 .

In the linear motor 1 of the first embodiment, a plurality of magnetic pole teeth 31 are formed on the back yoke 3, and a shear region of the driving magnetic flux is generated by the concavo-convex shape opposing the movable element 2 . , not only the armature 4 but also the back yoke 3 contributes to the generation of thrust. 5 : is a side view which shows the flow of magnetic flux in the linear motor 1 of Embodiment 1. As shown in FIG. In Fig. 5, arrows indicate the flow of magnetic flux. In the linear motor 1, while thrust is generated by the front end of the magnetic flux on the armature 4 side, thrust is also generated by the front end of the magnetic flux on the back yoke 3 side, so that the linear motor 1 ) is the sum of these two thrusts. Further, in the linear motor in which the magnetic pole teeth 31 are not formed as in the first embodiment and the back yoke is of a flat plate type, no thrust is generated on the back yoke side, and there is only thrust due to the shear of the magnetic flux on the armature side.

In the linear motor 1 of Embodiment 1, since a gap is also provided between the mover 2 and the back yoke 3, there is a concern that the thrust will decrease due to this gap. However, as described above, since thrust can also be generated on the back yoke 3 side, the drop in thrust due to the gap can be compensated for, and a large thrust can be realized.

From the above, in the linear motor 1 of the first embodiment, the suction force acting on the mover 2 can be significantly reduced while maintaining a large thrust. Accordingly, the movable element 2 hardly undergoes warpage due to the suction force, and the dimensional accuracy of the processing machine of the semiconductor manufacturing apparatus using the linear motor 1 or the like is very high.

Moreover, in the linear motor 1 of Embodiment 1, since the attraction force can be made small, even if it uses the permanent magnet 21 and the holding edge 22 with small rigidity, a trouble does not arise. Accordingly, it is possible to achieve downsizing of the movable element 2 and realize a large acceleration along with the weight reduction of the movable element 2 . In addition, since wear of the movable element 2 is also small, the life of the linear motor 1 can be increased.

In a linear motor, it is common to provide a linear guide on the side surface of the mover as described later in order to smooth the movement of the mover. A small one can be used, which also contributes to miniaturization and longer life of the linear motor.

In the linear motor 1 of Embodiment 1, the length of the movable element 2 is made shorter than the length of the back yoke 3 and the armature 4, and further miniaturization, weight reduction, and high speed are aimed at.

Hereinafter, the specific structure of the linear motor 1 in Embodiment 1 manufactured by this inventor, and the characteristic of the manufactured linear motor 1 are demonstrated.

First, the movable element 2 is manufactured. From a block of Nd-Fe-B type rare-earth magnets (Br=1.395T, HcJ=1273 kA/m), 14 rectangular permanent magnets 21 having a thickness of 5 mm, a width of 12 mm, and a length of 82 mm are cut out. The cut out permanent magnet 21 is magnetized in the thickness direction. Next, the holding edge 22 shown in FIG. 4 is cut out by wire cut from the SUS board of thickness 3mm. The cut holding edge 22 is adhesively fixed to a fixing plate 23 made of a SUS plate having a thickness of 0.2 mm. Then, in the hole 221 of the holding edge 22, 14 permanent magnets 21 coated with an adhesive so that the magnetization directions of the adjacent permanent magnets 21 are opposite to each other, a skew angle θ=3.2 ° is inserted, and the permanent magnet 21 is adhesively fixed to the holding edge 22 and the fixing plate 23 . Here, the thickness of the retaining frame 22 is set to 3 mm with respect to the thickness of the permanent magnet 21 of 5 mm so as to realize both weight reduction of the movable element 2 and high rigidity of the magnet arrangement.

In addition, unlike the above example, you may make it manufacture the holding|maintenance rim 22 by the method of overlapping 6 sheets which were punched by press work to a 0.5 mm-thick SUS board, and fixing by caulking process. In this case, reduction of manufacturing cost can be aimed at.

Next, the back yoke 3 is manufactured. FIG. 6 is a diagram showing the side shape of the back yoke 3 in the linear motor 1 according to the first embodiment.

From mild steel (JIS standard G3101 type code SS400 material), a block having the dimensions shown in Fig. 6 was cut, and 18 magnetic pole teeth 31 of the same shape (width: 6 mm, height: 3 mm, length: 82 mm, magnetic pole area: 492) mm 2 ) at an equal pitch (15.12 mm), and a back yoke 3 was produced.

Next, the armature 4 is manufactured. 7 : is a top view which shows the armature raw material used for manufacture of the armature 4 in the linear motor 1 of Embodiment 1. As shown in FIG. The armature material 44 having the shape shown in Fig. 7 was cut out from a 0.5 mm thick silicon steel sheet (JIS standard C2552 type code 50A 800 material), 164 sheets were cut out, the cut 164 sheets were overlapped, the side surfaces were melted with a CO2 laser, and the width was integrated. A block body of 82 mm, 31 mm in height, and 263.04 mm in length (18 identically shaped magnetic poles 42 (width: 6 mm, height: 25 mm, length: 82 mm, magnetic pole area: 492 mm2) on the core 41) was set at equal pitch (15.12). mm) was obtained.

Next, a coil is inserted into this block body. 8 : is a figure which shows the coil of the armature 4 in the linear motor 1 of Embodiment 1. FIG. A drive coil 43 was obtained by impregnating with varnish and fixing 17 turns of an enamel-coated conducting wire having a diameter of 2 mm to the arm portion of each magnetic pole tooth 42 of the armature 4 .

U, V, and W in Fig. 8 each indicate U-phase, V-phase, and W-phase of a three-phase AC power supply, and the coils of each phase are all serially connected. U coil, V coil, and W coil are connected so that current flows clockwise when viewed from above, and -U coil, -V coil and -W coil are connected so that current flows counterclockwise when viewed from above. And, the armature (4) is manufactured. Then, six U coils, -U coils, V coils, -V coils, W coils, and -W coils were star-connected and connected to a three-phase AC power supply.

Next, the produced back yoke 3 and the armature 4 are fixed using a jig so that the distance between them is maintained at a constant 6 mm. Moreover, although the space|interval of the back yoke 3 and the armature 4 was fixed so that it might become 6 mm, let this space|interval be a structure which can be adjusted after linear motor 1 assembly. Next, after mounting a linear guide (not shown) on the side surface of the mover 2 , the back yoke 3 and the armature 4 are spaced apart from each other by a predetermined distance. distance, insert the mover (2) with a thickness of 5 mm, and manufacture the linear motor (1). At this time, the distance between the distance between the magnetic pole values 31 of the mover 2 and the back yoke 3 and the distance between the magnetic pole values 42 of the mover 2 and the armature 4 are either 0.5 mm. Moreover, between the linear guide and the armature 4, a load cell was provided so that the attraction|suction force could be measured.

Since it has a structure in which the distance between the back yoke 3 and the armature 4 can be adjusted, it is movable with the distance between the mover 2 and the armature 4 (stimulus value 42) being constant. The distance between the ruler 2 and the back yoke 3 (the magnetic pole value 31) can be set arbitrarily and can be made variable. In addition, by adjusting the insertion position of the movable element 2 to the gap between the back yoke 3 and the armature 4, the distance between the movable element 2 and the back yoke 3 (the magnetic pole value 31), And, it is also possible to set the ratio of the distance between the distance between the movable element 2 and the armature 4 (the magnetic pole value 42) to a desired value.

In addition, as a mechanism for adjusting the gap between the linear guide supporting the armature 4 and the movable element 2 and between the armature 4 and the back yoke 3, the height is adjusted by inserting a gap adjusting screw. A mechanism for adjusting the height by inserting a shim plate having a tapered cross-sectional shape with a screw is employable.

9A and 9B are diagrams showing the configuration of the linear motor 1 of an example of Embodiment 1 produced in this way, and FIG. 9A is a top view thereof, and FIG. 9B is a side view thereof. In FIG. 9B , the discoloration arrow indicates the magnetization direction of the permanent magnet 21 , and the solid arrow indicates the moving direction of the movable element 2 . In addition, the detail of the manufacturing specification of this linear motor 1 is as follows.

Stimulus configuration: 7 poles 6 slots

Material of permanent magnet 21: Nd-Fe-B type rare earth magnet (NMX-S49CH made by Hitachi Metals)

Shape of permanent magnet 21: thickness 5.0mm, width 12mm, length 82mm

Pitch of permanent magnet (21): 12.96mm

Permanent magnet (21) skew angle: 3.2°

The shape of the back yoke (3): 6.0mm thick, 90mm wide, 263.04mm long

Material of back yoke (3): mild steel (JIS standard G3101 type code SS400 material)

Shape of magnetic pole 31: width 6.0mm, height: 3.0mm, length: 82mm

Pitch of magnetic pole teeth 31: 15.12mm

The build of the core 41: 31mm high, 82mm wide, 263.04mm long

Material of core 41: silicon steel plate (JIS standard C2552 type symbol 50A 800 material)

Shape of magnetic pole (42): width 6.0mm, height: 25mm, length: 82mm

Pitch of magnetic pole teeth 42: 15.12mm

The shape of the drive coil 43: width 15.12mm, height 23mm, length 91.12mm

Winding thickness of drive coil 43: 4.06mm

The diameter of the coil of the drive coil 43, the number of turns: 2 mm in diameter, 17 turns

Coil Resistance (1 pc.): 0.0189Ω

Mass of mover (2): 516.6 g

In the above-described linear motor 1, the length (190 mm) of the movable element 2 is shorter than the length (263.04 mm in both) of the back yoke 3 and the armature 4 . The pitch of the magnetic pole values 31 in the back yoke 3 and the pitch of the magnetic pole values 42 in the armature 4 are the same at 15.12 mm in both, and the magnetic pole values 31 and 42 are in the movable direction. is in the same position in

The shape of the magnetic pole face of the magnetic pole teeth 31 opposing the magnet arrangement and the shape of the magnetic pole face of the magnetic pole teeth 42 opposing the magnet arrangement are rectangular with the same dimensions. That is, the width (dimension in the moving direction) of the magnetic pole teeth 31 and the width (the dimension in the moving direction) of the magnetic pole teeth 42 are the same at 6 mm, and the magnetic pole area of the magnetic pole teeth 31 opposite to the magnet arrangement and The magnetic pole area of the magnetic pole teeth 42 opposite to the magnet arrangement is the same at 492 mm 2 in both cases.

The linear motor 1 assembled in this way is installed on the test bench for measuring thrust, and it is driven by a three-phase constant current power source synchronized with the position of the mover 2 (magnet arrangement) to move the mover 2, , thrust and suction were measured.

FIG. 10 is a graph showing the thrust fluctuation with respect to the electric angle of the linear motor 1 according to the example of the first embodiment. This thrust fluctuation is the thrust (U-phase, V-phase, The change of 3-phase combined thrust of W phase) is shown. In FIG. 10 , the horizontal axis is electric angle [°], and the vertical axis is thrust [N]. In the drawing, a is the thrust by the armature 4, b in the drawing is the thrust by the back yoke 3, and in the drawing, c is the overall thrust (the thrust by the armature 4 and the back yoke 3) added thrust of the thrust) respectively. As shown in FIG. 10, it turns out that the substantially constant large thrust is acquired over the whole area.

11 is a graph showing thrust characteristics of the linear motor 1 according to an example of the first embodiment. This thrust characteristic has shown the characteristic when the electric current applied to the drive coil 43 is changed. In FIG. 11 , the horizontal axis is the driving magnetomotive force [A], the left vertical axis is the thrust [N], and the right vertical axis is the thrust magnetomotive force ratio [N/A]. In addition, in the figure, a is a thrust, and in the figure, b has shown the thrust magnetomotive force ratio, respectively. In this linear motor 1, the thrust proportional limit (thrust magnetomotive force ratio is reduced by 10%) is 1000N at the time of 1200A driving magnetism force.

12 is a graph showing the suction force characteristics of the linear motor 1 of an example of the first embodiment. This attractive force characteristic shows the characteristic when the electric current applied to the drive coil 43 is changed. In FIG. 12 , the horizontal axis is the driving magnetomotive force [A], and the vertical axis is the attraction force [N]. In addition, the suction force indicates that the movable element 2 is attracted to the armature 4 side from the + side, and the movable element 2 is attracted to the back yoke 3 side from the - side. As the driving magnetic force increases, the attractive force also increases. For example, when the driving magnetic force is 1200 A, the movable element 2 is attracted to the back yoke 3 side with an attractive force of about 290 N.

By the way, in order to compare and evaluate the linear motor 1 of Embodiment 1 with the conventional linear motor, two types of linear motors (the first conventional example and the second conventional example) are produced as a conventional example, and such characteristics (thrust and suction power) were measured.

First, the configuration of the first conventional example will be described. Fig. 13 is a side view showing the configuration of the linear motor of the first conventional example. The first conventional example is a linear motor (integrated linear motor) having a configuration according to Patent Documents 1 or 2.

The linear motor 50 of the first prior art includes a movable element 51 formed by integrating a magnet array 52 and a back yoke 53, and an armature 54 arranged opposite to the movable element 51 with an interval therebetween. Have. In the first conventional example, the structure in which the magnet arrangement 52 and the back yoke 53 are integrated functions as a mover, and the armature 54 functions as a stator.

The configuration of the magnet arrangement 52 is the same as the configuration of the magnet arrangement of the movable element 2 described above. That is, the magnet arrangement 52 is constituted by holding and fixing a plurality of rectangular permanent magnets 55 to a holding edge of a non-magnetic material at equal pitches and installing them in the movable direction (left and right direction in FIG. 13), and each permanent magnet Reference numeral 55 is magnetized in the thickness direction (up-down direction in Fig. 13), and the magnetization direction of the permanent magnets 55 and 55 adjacent to each other is opposite. In the linear motor 50 of the first conventional example, this magnet array 52 is bonded to a flat plate-shaped back yoke 53 made of mild steel. In addition, the configuration of the armature 54 is the same as that of the armature 4 described above, and a plurality of magnetic pole teeth 57 are integrally provided on the core 56 at equal pitches in the movable direction, and each magnetic pole teeth 57 ) a driving coil 58 is wound.

14A and 14B are diagrams showing the configuration of the linear motor 50 of this first conventional example, and FIG. 14A is a top view thereof, and FIG. 14B is a side view thereof. In FIG. 14B , the discoloration arrow indicates the magnetization direction of the permanent magnet 55 , and the solid arrow indicates the moving direction of the movable element 51 . In addition, the magnitude|size of the space|interval of the movable element 51 and the armature 54 is set to 0.5 mm or 1 mm. The detail of the manufacturing specification of this linear motor 50 is as follows.

Stimulus configuration: 7 poles 6 slots

Material of permanent magnet (55): Nd-Fe-B series rare earth magnet (NMX-S49CH made by Hitachi Metals)

Shape of permanent magnet (55): thickness 5.0mm, width 12mm, length 82mm

Pitch of permanent magnet (55): 12.96mm

Permanent magnet (55) skew angle: 3.2°

The shape of the back yoke (53): 6.0mm thick, 90mm wide, 190mm long

Material of back yoke (53): mild steel (JIS standard G3101 type code SS400 material)

Core 56 build: 31mm high, 82mm wide, 263.04mm long

Material of core 56: silicon steel plate (JIS standard C2552 type symbol 50A 800 material)

Shape of magnetic pole (57): width 6.0mm, height: 25mm, length: 82mm

Pitch of magnetic pole teeth (57): 15.12mm

The shape of the drive coil 58: width 15.12mm, height 23mm, length 91.12mm

Winding thickness of drive coil 58: 4.06mm

The diameter of the coil of the drive coil 58, the number of turns: 2mm in diameter, 17 turns

Coil Resistance (1 pc.): 0.0189Ω

Mass of mover 51 (magnet array 52 + back yoke 53): 1321.01 g

The length in the movable direction (left-right direction in Fig. 13) of the movable armature 51 (the integrated configuration of the magnet array 52 and the back yoke 53) is shorter than the length of the armature 54, and the difference in this length is It becomes an operable stroke of the linear motor 50 .

Next, the configuration of the second conventional example will be described. Fig. 15 is a side view showing the configuration of the linear motor of the second conventional example. The second conventional example is a linear motor (separation type linear motor) having a configuration according to Patent Documents 3 to 6. In Fig. 15, only the magnet array 62 is cross-sectional in a direction parallel to the movable direction so that the arrangement of magnets can be understood.

The linear motor 60 of the second prior art includes a magnet array 62 , a back yoke 63 disposed opposite to the magnet array 62 at a distance from the magnet array 62 , and a back yoke 63 disposed at a distance from the magnet array 62 . ) and has an armature 64 disposed opposite to the side. Only the magnet arrangement 62 functions as a mover, and the back yoke 63 and the armature 64 function as a stator.

The configuration of the magnet arrangement 62 is the same as the configuration of the magnet arrangement of the movable element 2 described above. That is, the magnet arrangement 62 is constituted by holding and fixing a plurality of rectangular permanent magnets 65 to a holding edge of a non-magnetic material at equal pitches and installing them in the movable direction (left-right direction in Fig. 15), and each permanent magnet Reference numeral 65 is magnetized in the thickness direction (up-and-down direction in Fig. 15), and the magnetization directions of the permanent magnets 65 and 65 adjacent to each other are opposite. The back yoke 63 made of mild steel has a flat surface not only on the side not facing the magnet arrangement 62 but also on the side facing the magnet arrangement 62, and has the same shape as the linear motor 1 of the first embodiment. There are no stimuli. Further, the configuration of the armature 64 is the same as that of the armature 4 described above, and a plurality of magnetic pole teeth 67 are integrally provided on the core 66 at equal pitches in the movable direction, and each magnetic pole teeth 67 are provided integrally. ), the driving coil 68 is wound.

16A and 16B are views showing the configuration of the linear motor 60 of this second conventional example, and Fig. 16A is a top view thereof, and Fig. 16B is a side view thereof. In Fig. 16B, the discoloration arrow indicates the magnetization direction of the permanent magnet 65, and the solid arrow indicates the moving direction of the magnet arrangement 62 (movable element). Moreover, the magnitude|size of the space|interval of the magnet arrangement|sequence 62 and the back yoke 63, and the size of the space|interval of the magnet arrangement|sequence 62 and the armature 64 are both set to 0.5 mm. In addition, the detail of the manufacturing specification of this linear motor 60 is as follows.

Stimulus configuration: 7 poles 6 slots

Material of permanent magnet (65): Nd-Fe-B series rare earth magnet (NMX-S49CH made by Hitachi Metals)

Shape of permanent magnet (65): thickness 5.0mm, width 12mm, length 82mm

Pitch of permanent magnet (65): 12.96mm

Permanent magnet (65) skew angle: 3.2°

The shape of the back yoke (63): 6.0mm thick, 90mm wide, 215mm long

Material of back yoke (63): mild steel (JIS standard G3101 type code SS400 material)

The build of the core (66): 31mm high, 82mm wide, 263.04mm long

Material of core 66: silicon steel plate (JIS standard C2552 type symbol 50A800 material)

The shape of the magnetic pole tooth 67: Width 6.0mm, Height: 25mm, Length: 82mm

Pitch of magnetic pole teeth 67: 15.12mm

Shape of drive coil 68: width 15.12mm, height 23mm, length 91.12mm

Winding thickness of drive coil 68: 4.06mm

The diameter of the coil of the drive coil 68, the number of turns: 2mm in diameter, 17 turns

Coil Resistance (1 pc.): 0.0189Ω

Mass of the mover (magnet array 62): 516.6 g

The length of the magnet arrangement 62 in the movable direction (left-right direction in FIG. 15 ) is shorter than the length of the armature 64 , and the difference in this length becomes the operable stroke of the linear motor 60 .

A comparison of the characteristics (thrust and attraction force) in the examples of the first conventional example, the second conventional example, and the first embodiment described above will be described.

Fig. 17 is a graph showing the average thrust in the linear motors of the first conventional example, the second conventional example, and the example of the first embodiment. Fig. 17 shows the average thrust [N] when the driving magnetic force is 1200A. 18 is a graph showing the average suction force in the linear motors of the first conventional example, the second conventional example, and the example. Fig. 18 shows the average attractive force [N] when the driving magnetic force is 1200A. Here, the average thrust and the average attractive force measure (calculate) the thrust and the attractive force at 25 points at 15° intervals in the range of U-phase electrical angle 0° to 360°, and calculate the average.

17 and 18, A denotes a linear motor 50 (in the first conventional example in which the magnet arrangement 52 and the back yoke 53 are integrated), the distance between the movable element 51 and the armature 54 being 0.5 mm ( Hereinafter, referred to as a linear motor 50A), B denotes a linear motor in which the distance between the movable element 51 and the armature 54 is 1 mm in the first conventional example in which the magnet array 52 and the back yoke 53 are integrated. (50) (hereinafter referred to as a linear motor 50B), where C is the distance between the magnet array 62 and the back yoke 63 in the second conventional example in which the magnet array 62 and the back yoke 63 are spaced apart. , and a linear motor 60 in which the distance between the magnet array 62 and the armature 64 is 0.5 mm, and D is the back yoke 3 spaced apart from the mover 2 (magnet array). In the example of Embodiment 1 in which the magnetic pole teeth 31 are formed, the distance between the mover 2 and the back yoke 3 and the distance between the mover 2 and the armature 4 are both linear. motor (1).

In the linear motor 50A of the first prior art example (A in the figure), the thrust is the largest, 1030N, but the suction force is 4200N, which is a large numerical value about four times the thrust. In the linear motor 50B (B in the drawing) as a countermeasure for reducing this attractive force, the reduction in the obtained thrust is remarkable and becomes 909N, whereas the attractive force is 3360N without much reduction. Therefore, it is understood that no sufficient countermeasures have been taken.

In the linear motor 60 (C in the drawing) of the second conventional example, a relatively large thrust of 980 N can be obtained, but in the suction force, it is attracted to the back yoke 63 side by a large force of 1712 N, and the suction force is not sufficiently reduced. didn't

On the other hand, in the linear motor 1 (D in the figure) of the example of Embodiment 1, the large thrust of 1000 N which is comparable to the linear motor 50A can be acquired. Moreover, the suction force is greatly reduced to 290N (about 1/14 of the linear motor 50A) on the back yoke 3 side. Therefore, in the linear motor 1 of an example of Embodiment 1, it has been demonstrated that a suction force can be reduced significantly, maintaining a large thrust.

By the way, in the linear motor 1 of the example of Embodiment 1, as also shown in FIG. 12, the magnitude|size of the attraction|suction force changes with the magnitude|size of a drive magnetomotive force. Accordingly, if the size of the distance between the movable element 2 and the back yoke 3 is adjusted in accordance with the frequently used thrust region (drive magnetomotive force), the suction force can be further reduced.

In the example of Embodiment 1 described above, the distance between the mover 2 and the back yoke 3 and the distance between the mover 2 and the armature 4 were both equal to 0.5 mm. In another example of 1, the distance between the mover 2 and the armature 4 remains 0.5 mm, and the distance between the mover 2 and the back yoke 3 is set to 0.74 mm. In addition, the other structure is the same as that of the above-mentioned example.

19 is a graph showing thrust characteristics of the linear motor 1 of another example of the first embodiment, and FIG. 20 is a graph showing the suction force characteristics of the linear motor 1 of another example of the first embodiment. In FIG. 19 , the horizontal axis indicates the driving magnetomotive force [A], the left vertical axis indicates the thrust [N], and the right vertical axis indicates the thrust magnetomotive force ratio [N/A], a is the thrust, and b indicates the thrust magnetomotive force ratio, respectively. In addition, in Fig. 20, the horizontal axis is the driving magnetomotive force [A], and the vertical axis is the attraction force [N].

In another example, when the driving magnetism force is 1200A, the thrust force becomes 978N, which is slightly lower than the above example, but in the case of the driving magnetism force of 1200A, the attraction force is only 18N, so almost zero can be realized. This is a suction force at a level that can ignore deformation or lifetime deterioration due to the suction force on the linear guide, the mover, or surrounding structures. Therefore, it turns out that the linear motor 1 of another example is suitable for the objective of reduction of a suction force compared with the example mentioned above, when using with the driving magneto force of the vicinity of 1200 A.

Further, as another example of the first embodiment, a linear motor in which the distance between the movable element 2 and the armature 4 is 0.5 mm and the distance between the movable element 2 and the back yoke 3 is 0.66 mm ( 1) is produced. In addition, the other structure is the same as that of the above-mentioned example.

FIG. 21 is a graph showing the thrust characteristics of the linear motor 1 according to still another example of the first embodiment, and FIG. 22 is a graph showing the attractive force characteristics of the linear motor 1 according to another example of the first embodiment. In FIG. 21 , the horizontal axis indicates the driving magnetomotive force [A], the left vertical axis indicates the thrust [N], and the right vertical axis indicates the thrust magnetomotive force ratio [N/A], a is the thrust, and b indicates the thrust magnetomotive force ratio, respectively. In addition, in Fig. 22, the horizontal axis is the driving magnetomotive force [A], and the vertical axis is the attraction force [N].

In another example, when the driving magnetism force is 1200A, the thrust becomes 984N, which is slightly lower than the above example, but in the case of the driving magnetism force of 600A, the attraction force is only 5N, so almost zero can be realized. Therefore, it turns out that the linear motor 1 of another example is said to be optimal in order to reduce a suction force when using with the driving magneto force of 600 A vicinity.

From the above, by optimally setting the size of the interval between the movable element 2 and the back yoke 3 according to the area of high frequency use, the suction force can be significantly reduced and almost zero can be achieved. As a result, it is possible to prevent deterioration of dimensional accuracy due to warpage of the movable element 2 (magnet arrangement), a decrease in lifespan due to a heavy load on the linear guide, and the like.

In addition, in the above-described form, an example has been described in which the size of the interval between the movable element 2 and the armature 4 is fixed and the size of the interval between the movable element 2 and the back yoke 3 is varied. Conversely, an example of changing the size of the gap between the mover 2 and the armature 4 by fixing the size of the gap between the mover 2 and the back yoke 3, the back yoke 3 and the armature 4 It is also possible to realize a suction force close to zero by an example in which the position of the movable element 2 is changed by fixing the size of the interval of .

Further, in the above-described form, the linear motor 1 having a structure in which the mover 2 is shorter than the armature 4 has been described. Formation of stimulus teeth on the back yoke) is applicable.

(Basic example of Embodiment 2)

23 and 24 are a perspective view and a side view showing a configuration example of the linear motor 1 according to the second embodiment. 23 and 24, only the movable element 2 is cross-sectional in a direction parallel to the movable direction so that the arrangement of the magnet can be understood.

The linear motor 1 of the second embodiment includes a movable element 2, a back yoke 3, and an armature 4, and the back yoke 3 and the armature 4 are a stator, similarly to the first embodiment. function as

In addition, the structure of the mover 2 and the armature 4 in the linear motor 1 of Embodiment 2 is the movable element 2 and the armature 4 in the linear motor 1 of Embodiment 1 mentioned above. Since it is the same as the configuration of , a description thereof will be omitted.

In the linear motor 1 of the second embodiment, the configuration of the back yoke 3 is different from the linear motor 1 of the first embodiment. The back yoke 3 includes magnetic pole teeth 31 and a base plate 32 . The base plate 32 has a rectangular plate shape. The magnetic pole teeth 31 are being fixed to the base plate 32 . The magnetic pole teeth 31 are fixed so that a part thereof protrudes from the base plate 32 . The shape of the protruding portion is a rectangular parallelepiped shape. The plurality of magnetic pole teeth 31 are arranged at equal pitch along the longitudinal direction of the base plate 32 . The magnetic pole teeth 31 are formed by, for example, a laminated silicon steel plate as described later. The base plate 32 is formed of, for example, carbon steel such as SS400.

The back yoke 3 and the armature 4 are disposed to face each other with a distance away from each other. Then, the movable element 2 is disposed at the interval. The first face of the mover 2 is opposed to the back yoke 3 at intervals. A second face opposite to the first face of the mover 2 faces the armature 4 at a distance.

As shown in FIG. 24, the lengths in the movable direction (left-right direction in FIG. 24) of the back yoke 3 and the armature 4 are substantially the same. In addition, the pitch of the magnetic pole values 31 in the back yoke 3 is the same as the pitch of the magnetic pole values 42 of the armature 4 . The position of each magnetic pole tooth 31 in the back yoke 3 is the same as the position of each magnetic pole tooth 42 of the armature 4 in the moving direction of the mover 2 . Moreover, the magnetic pole surface of the magnetic pole tooth 31 and the magnetic pole surface of the magnetic pole tooth 42 are the same rectangular shape, and have the same area. Further, the interval between the movable element 2 and the back yoke 3 is substantially the same as the interval between the movable element 2 and the armature 4 .

In the movable element 2, the magnetization directions of the permanent magnets 21 and 21 adjacent to each other are reversed. When the movable armature 2 is disposed at the interval between the back yoke 3 and the armature 4, a permanent magnet 21 magnetized in a direction from the back yoke 3 side toward the armature 4 side, and the armature 4 ) side, the permanent magnets 21 magnetized in a direction toward the back yoke 3 side are alternately arranged.

During the operation of the linear motor 1 , an attraction force is generated between the magnetic pole teeth 31 of the back yoke 3 and the permanent magnet 21 of the mover 2 . In addition, an attraction force is also generated between the magnetic pole teeth 42 of the armature 4 and the permanent magnet 21 of the movable element 2 . The two suction forces acting on the mover 2 are opposite to each other. By adjusting the magnetic circuit, such as making the magnetic pole surface of the magnetic pole tooth 31 and the magnetic pole surface of the magnetic pole tooth 42 the same rectangular shape or the same area, the magnitude of the attraction force can be made substantially the same. Accordingly, the attraction force generated between the magnetic pole teeth 31 and the permanent magnet 21 and the attraction force generated between the magnetic pole teeth 42 and the permanent magnet 21 can be balanced. That is, the two suction forces can be erased from each other. In addition, when it is difficult to balance the two attractive forces due to factors such as processing errors and assembly errors, the distance between the magnetic pole teeth 31 and the permanent magnet 21 or the distance between the magnetic pole teeth 42 and the permanent magnet 21 is adjusted. and balance the two suction powers.

As mentioned above, since the linear motor 1 of Embodiment 2 has the same structure as the linear motor 1 of Embodiment 1 mentioned above, also in the linear motor 1 of Embodiment 2, the linear of Embodiment 1 Like the motor 1, the suction force acting on the mover 2 can be greatly reduced while maintaining a large thrust. Also in the linear motor 1 of the second embodiment, it is possible to reduce the detent force of the movable element 2 as in the linear motor 1 of the first embodiment.

Hereinafter, the structure of the back yoke 3 which is the characteristic of Embodiment 2 is demonstrated in detail. 25 is a perspective view showing a configuration example of the magnetic pole teeth 31 included in the back yoke 3 . The magnetic pole tooth 31 has a T-shape in cross section and has two protrusions 31a and 31a protruding from the bottom (lower side in Fig. 25) in the short length direction. For this reason, the protrusions 31a and 31a (which are horizontally H-shaped in FIG. 25 ) are portions that engage with the recesses 32a and 32a of a dovetail groove 321 described later. During the operation of the linear motor 1 , the short longitudinal direction of the magnetic pole teeth 31 becomes a direction parallel to the moving direction of the mover 2 .

The magnetic pole teeth 31 are formed by stacking the magnetic pole pieces 311 . The pole piece 311 includes a protrusion 311a for engagement formed by notching a part of the rectangular plate shape. The pole piece 311 is formed of a thin plate such as silicon steel having soft magnetic properties. The stacked magnetic pole pieces 311 are fixed to each other by heat welding, caulking, or the like. In the case of heat welding, for example, first, a heat-hardening adhesive is applied to the surface of the pole piece 311 and a heat-sealable coating film is laminated, followed by heating while applying pressure to the plate surface. The magnetic pole pieces 311 are fixed to each other by heating.

In addition, the eddy current damage is reduced as the plate thickness of the magnetic pole pieces 311 constituting the magnetic pole teeth 31 is reduced, that is, the number of the magnetic pole pieces 311 is increased. In consideration of strength and assembly effort, the thickness of the pole piece 311 is preferably set to about 0.2 to 0.5 mm. The number and plate thickness of the magnetic pole pieces 311 constituting the magnetic pole teeth 31 may be appropriately designed according to the required specifications.

26 is a partial perspective view showing a configuration example of the base plate 32 included in the back yoke 3 . For convenience of explanation, FIG. 26 is drawn with the vertical direction reversed from that of FIGS. 24 and 25 . The base plate 32 is provided with a dovetail groove 321 along the short longitudinal direction. The dovetail groove 321 has a shape corresponding to the protrusion 311a of the magnetic pole piece 311 (the protrusion 31a of the magnetic pole tooth 31). The dovetail groove 321 has a recessed portion 32a corresponding to the projection 311a (projection 31a). 24 and 25 , a plurality of dovetail grooves 321 are formed in the base plate 32 . The plurality of dovetail grooves 321 are provided at equal pitches along the movable direction of the movable element 2 . The arrangement direction of the plurality of dovetail grooves 321 is parallel to the moving direction of the mover 2 when the linear motor 1 is operating.

27 is a partial perspective view of the back yoke 3 . Similarly to FIG. 26, for convenience of explanation, the up-down direction is reversed to FIG. 24 and FIG. 25, and is drawn. In the back yoke 3 , the projection 31a of the magnetic pole tooth 31 engages the dovetail groove 321 .

The magnetic pole teeth 31 are fixed to the base plate 32, for example, as follows. An adhesive is applied to one or both of the dovetail groove 321 and the magnetic pole 31 . Positioning is determined by inserting the magnetic pole teeth 31 into the dovetail grooves 321 using a jig or the like. When the adhesive has hardened, the jig is removed. In addition, the fixing method is not limited to this. Other methods may be used as long as the pitch of the magnetic pole teeth 31 or the amount of the magnetic pole teeth 31 protruding from the base plate 32 can be fixed within a predetermined error range.

The linear motor 1 applies a three-phase alternating current to the drive coil 43 of the armature 4, so that the magnetic pole value 42 of the armature 4, the permanent magnet 21 of the mover 2, and the back yoke ( The magnetic flux flowing through the magnetic pole value 31 of 3) is generated. The suction force generated between the movable element 2 and the armature 4 due to the generated magnetic flux and the suction force generated between the movable element 2 and the back yoke 3 become the thrust of the movable element 2, and the movable element 2 is movable. Ruler (2) moves.

Next, the reduction of the eddy current will be described. 28 is a partial side view of the linear motor 1 . In Fig. 28, an example of the flow of magnetic flux is indicated by a solid arrow, and an example of an eddy current is indicated by a dotted arrow. As shown in Fig. 28, in the magnetic pole value 31, magnetic flux flows in the vertical direction on the ground. That is, it flows in the direction parallel to the plate surface of the magnetic pole piece 311 which comprises the magnetic pole tooth 31. Eddy currents tend to flow in a direction that opposes the change in magnetic flux on a plane perpendicular to the direction in which the magnetic flux flows. That is, in the case shown in FIG. 28, it is going to flow counterclockwise with respect to the direction in which magnetic flux flows. The direction of this eddy current is a direction penetrating the plate surface of the magnetic pole piece 311 constituting the magnetic pole tooth 31 . However, since the magnetic pole teeth 31 are stacked with a plurality of magnetic pole pieces 311 and the electrical resistance between the magnetic pole pieces 311 is large, it is possible to reduce the eddy current. Moreover, when an insulating film is applied to the plate surface (surface) of the pole pieces 311, it becomes possible to further reduce the eddy current flowing between the pole pieces 311.

29A and 29B are graphs showing an example of a joule loss due to an eddy current, FIG. 29A is a graph showing a joule loss of a linear motor according to the related art, and FIG. 29B is a linear motor 1 in a basic example of the second embodiment. It is a graph showing the joule loss of The difference in the configuration between the linear motor according to the related art and the linear motor in the second embodiment is as follows. In the former case, the magnetic pole values do not have a laminated structure. For example, the excitation value in electrons is a block of soft magnetic material. Alternatively, the base plate 32 and the magnetic pole teeth 31 may be integrally formed of a soft magnetic material. In contrast, in the latter, the magnetic pole teeth 31 have a laminated structure. Other conditions, the structure and dimensions of the linear motor, the number of turns of the coil, and driving conditions are the same. For example, the coil drive current was 70.6 A, and the moving speed of the mover was 1000 mm/s.

29A and 29B are electric angles indicating the position of the movable element 2 . The unit of the horizontal axis is degrees (°). The vertical axis of FIGS. 29A and 29B is the Joule loss due to the eddy current. The unit is watt (W). The graph labeled back yoke shows the joule loss to the back yoke. As shown in Fig. 29A, in the linear motor according to the related art that does not have a laminated structure of magnetic pole teeth, the joule loss to the back yoke is around 80 W, whereas the linear motor 1 according to the second embodiment in which magnetic pole teeth 31 have a laminated structure. ), the joule loss to the back yoke 3 is reduced to around 50 W.

In FIGS. 29A and 29B, graphs labeled U, V, and W represent absolute values of Joule losses due to energization occurring in coils U, V, and W, respectively. Moreover, although the joule loss to the coil by energization to the coil is the same in FIGS. 29A and 29B, a large difference is shown in the joule loss to the back yoke. This result is an example showing that the joule loss due to eddy current can be reduced in the case where the magnetic pole values are not laminated under the same dimension and shape when the laminate structure is used, and the size and speed of the linear motor The absolute value of the Joule loss due to the eddy current is changed by this, but the ratio of the effect of both at the same speed is maintained.

The linear motor 1 according to the second embodiment has the following effects. The magnetic pole teeth 31 are constituted by laminating magnetic pole pieces 311 formed of silicon steel plates. Therefore, the direction of the eddy current is a direction penetrating the plate surface. At this time, due to the distance between the surfaces of the magnetic pole pieces 311 , the contact resistance between the magnetic pole pieces, the oxide film formed on the surface of the magnetic pole pieces 311 , etc., the resistance in the eddy current direction at the magnetic pole teeth 31 is compared with the case where it is formed of a soft magnetic block, it is larger. Accordingly, it becomes possible to reduce the eddy current flowing through the magnetic pole teeth 31 . Further, the surface (laminated surface) of the pole piece 311 may be subjected to an insulating treatment such as forming a film of an insulating material. When the insulating treatment is applied, it becomes possible to further reduce the eddy current between the respective silicon steel sheets.

Moreover, in Embodiment 2, let the magnetic pole tooth 31 which the back yoke 3 has a laminated structure. For example, when the entire back yoke is formed of a laminated steel sheet, there is a concern that the rigidity is inferior. In that case, there is a possibility that the back yoke 3 may be warped due to the suction force generated between it and the movable element 2 . However, in the basic example, only the magnetic pole teeth 31 have a laminated structure, and the base plate 32 to which the magnetic pole teeth 31 are fixed does not have a laminated structure. Therefore, the bending of the back yoke 3 is related to the related art (the case where the magnetic pole teeth 31 and the base plate 32 are respectively formed of a soft magnetic material, or the magnetic pole teeth 31 and the base plate 32 are integrated with a soft magnetic material) Even when compared with the configuration by ), it is insignificant.

(First Modification of Embodiment 2)

The first modification relates to a form in which a part of the base plate constituting the back yoke 3 has a laminated structure. 30 is a side view showing another configuration example of the back yoke 3 . The back yoke 3 includes a base portion 33 and a magnetic pole block 34 . The stimulus value block 34 includes a part to be fitted 34a and a plurality of stimulus teeth 31 .

31 is a perspective view showing a configuration example of the magnetic pole block 34. As shown in FIG. The magnetic pole tooth block 34 is formed by laminating a plurality of magnetic pole tooth pieces (plate-shaped members) 341 . The stacking direction of the magnetic pole tooth pieces 341 is a direction intersecting with the arrangement direction of the magnetic pole teeth 31 . The magnetic pole tooth piece 341 includes a to-be-fitted portion 341a, a connecting portion 341b, and a plurality of protrusions 341c. The fitted portion 341a has an inverted trapezoidal cross-section. The fitted portion 341a is a portion to be the fitted portion 34a of the magnetic pole tooth block 34 . The protrusion 341c has a rectangular cross-section. The plurality of protrusions 341c are formed at equal pitches in the longitudinal direction of the magnetic pole tooth pieces 341 . The protrusion 341c is a portion that becomes the magnetic pole tooth 31 of the magnetic pole tooth block 34 . The connecting portion 341b is a portion positioned between the to-be-fitted portion 341a and the protruding portion 341c in the height direction of the magnetic pole tooth piece 341 . The connecting portion 341b connects the plurality of protruding portions 341c. The magnetic pole tooth piece 341 is formed of, for example, a silicon steel plate. The connecting portion 341b is a plate-shaped member constituting a laminated portion serving as a part of the base portion of the back yoke 3 . The protrusion 341c is a plate-shaped member constituting the magnetic pole teeth 31 . The magnetic pole tooth piece 341 is formed by integrating two plate-shaped members.

32 is a perspective view showing a configuration example of the base portion 33. As shown in FIG. The base part 33 shown in FIG. 32 is inverted upside down from the base part 33 shown in FIG. The base part 33 forms a rectangular plate shape. The base portion 33 is formed with a fitting groove 33a having a trapezoidal cross-section.

The fitting portion 34a of the magnetic pole tooth block 34 is fitted into the fitting groove 33a of the base portion 33 . In addition, in the base portion 33 , the length in the movable direction of the mover 2 may be set to match the length in the movable direction of the magnetic pole value block 34 . The magnetic pole tooth block 34 is fixed to the base part 33 as follows. After applying an adhesive to one or both of the fitting grooves 33a or the fitting portion 34a, fitting is performed. Thereby, the base part 33 and the magnetic pole tooth block 34 are fixed. As a result of the above, the back yoke 3 is formed.

Next, the reduction of the eddy current will be described. 33 is a partial side view of the linear motor 1 . In Fig. 33, an example of the flow of magnetic flux is indicated by a solid arrow, and an example of an eddy current is indicated by a dotted arrow. The reduction of the eddy current in the magnetic pole value 31 is the same as in the basic example described above, and therefore the description thereof is omitted. Here, the reduction of the eddy current in the connection part 341b of the magnetic pole value block 34 is demonstrated. As shown in Fig. 33, in the connecting portion 341b, magnetic flux flows in the left-right direction in the paper. That is, it flows in a direction parallel to the plate surface of the magnetic pole tooth piece 341 constituting the magnetic pole tooth block 34 . Eddy currents tend to flow in a direction that opposes the change of magnetic flux on a plane perpendicular to the direction in which the magnetic flux flows. That is, as shown in Fig. 33, the magnetic flux tends to flow counterclockwise with the direction in which the magnetic flux flows as an axis. The direction of this eddy current is a direction penetrating the plate surface of the magnetic pole tooth piece 341 constituting the magnetic pole tooth block 34 . However, since the magnetic pole tooth block 34 stacks a plurality of magnetic pole tooth pieces 341 and the resistance between the magnetic pole tooth pieces 341 becomes large, it becomes possible to reduce the eddy current. In addition, when an insulating film is applied to the plate surface, it becomes possible to further reduce the eddy current flowing between the magnetic pole tooth pieces 341 .

In addition, the height of the connection part 341b is demonstrated. As shown in Fig. 33, the height of the connecting portion 341b is denoted by d. The magnetic flux flowing between the adjacent magnetic pole teeth 31 flows in the left-right direction in the paper. The path through which the magnetic flux flows follows the shortest path. Therefore, the magnetic flux does not flow to the portion that is more than a certain distance away from the magnetic pole value 31 . Accordingly, the height d of the connecting portion 341b may be set to a value capable of sufficiently allowing the magnetic flux in the left and right directions of the paper to flow. In addition, the base portion 33 through which magnetic flux does not flow can be formed of a non-magnetic material. For example, the base part 33 is formed of alumina etc. which have high rigidity and a large elastic modulus. Alternatively, non-magnetic stainless steel or aluminum alloy may be used.

34A and 34B are graphs showing an example of a joule loss due to an eddy current, and FIG. 34A is a graph showing a joule loss of the linear motor 1 in the basic example. Fig. 34A is a rearrangement of Fig. 29B. 34B is a graph showing the joule loss of the linear motor 1 in the first modified example. In the basic example, the magnetic pole teeth 31 have a laminated structure, whereas in the first modified example, the magnetic pole teeth and a part of the base plate have a laminated structure. Other conditions, the structure and dimensions of the linear motor, the number of turns of the coil, and driving conditions are the same. For example, the coil drive current was 70.6 A, and the moving speed of the mover was 1000 mm/s.

As shown in Fig. 34A, in the linear motor 1 of the basic example, the joule loss of the back yoke 3 is around 50 W, whereas in the linear motor 1 of the first modification, as shown in Fig. 34B, the back yoke 3 is (3) Joule loss is reduced to around 2.5W. This is because, since the connecting portion 341b has a stacked structure, the eddy current caused by the magnetic flux flowing through the connecting portion 341b is also reduced. In FIGS. 34A and 34B, the graphs labeled U, V, and W show the absolute values of Joule losses due to energization occurring in the U-phase, V-phase, and W-phase of the coil, respectively. Moreover, although the joule loss to the coil by energization to the coil is the same in FIGS. 34A and 34B, there is a large difference in the joule loss to the back yoke. These results are examples showing that the latter can reduce Joule losses due to eddy currents when only the magnetic pole values are laminated under the same dimension and shape, and when the magnetic pole values and part of the back yoke are laminated. The absolute value of the joule loss due to the eddy current changes depending on the size of the motor or the speed of the linear motor, but the ratio of both effects at the same speed is maintained.

In the linear motor 1 in the first modification, the magnetic pole tooth block 34 is constituted by laminating silicon steel plates (pole tooth pieces 341). In the linear motor 1, in addition to the magnetic pole teeth 31, a part of the thickness direction from the connecting portion with the magnetic pole teeth 31 of the back yoke 3 has a laminated structure. Therefore, the magnetic flux flowing through the connecting portion 341b between the adjacent magnetic pole teeth 31 is in a direction parallel to the surface of the magnetic pole tooth piece 341 . The direction of the eddy current generated by the flow of magnetic flux is the direction penetrating the plate surface of the magnetic pole tooth piece 341 . However, due to the distance between the surfaces of the magnetic pole tooth pieces 341 and the oxide film formed on the surface, the resistance in the eddy current direction in the connection portion 341b is increased compared to the case where the laminated structure is not used. Accordingly, it becomes possible to reduce the eddy current flowing through the connecting portion 341b. Therefore, it becomes possible to further reduce the eddy current flowing through the back yoke 3 .

Further, in the first modification, the following effects reside in addition to the above-described effects in which the basic example 1 resides. Since it is possible to form the base portion 33, which is a part of the back yoke 3, of a non-magnetic material, it becomes possible to form it with a material having a high elastic modulus, for example, alumina. Thereby, since the rigidity of the whole back yoke 3 is increased, it is possible to reduce the deflection caused by the attraction force generated between the movable element 2 and the movable element 2 . Moreover, when the rigidity of the whole back yoke 3 exceeds the rigidity requested|required by the material of the base part 33, it becomes possible to make the back yoke 3 thin.

(Second Modification of Embodiment 2)

The second modification relates to a form in which a part of the base plate 32 constituting the back yoke 3 has a laminated structure. 35 is a side view showing another configuration example of the back yoke 3 . The back yoke 3 includes a plurality of back yoke units 301 and a back yoke unit 302 . The back yoke unit 301 includes a base portion 35 and a magnetic pole unit 36 . The back yoke unit 302 includes a base portion 35 and a magnetic pole unit 37 . The difference between the back yoke unit 301 and the back yoke unit 302 is the difference between the included stimulation value units. One end of the back yoke 3 is referred to as a back yoke unit 301 , and the other end is referred to as a back yoke unit 302 . Thereby, as shown in FIG. 35, it becomes possible to comprise the back yoke 3 provided with the magnetic pole teeth 31 at both ends.

36A and 36B are perspective views showing a configuration example of the stimulation value units 36 and 37 , FIG. 36A shows a configuration example of the stimulation value unit 36 , and FIG. 36B shows a configuration example of the stimulation value unit 37 . The magnetic pole unit 36 includes a plurality of magnetic pole teeth 31 formed in a comb-tooth shape and a to-be-fitted portion 36a. The magnetic pole teeth 31 have a rectangular cross-section. The to-be-fitted portion 36a has an inverted trapezoidal cross-section.

The magnetic pole tooth unit 36 is formed by stacking a plurality of magnetic pole tooth pieces (plate-shaped members) 361 . The stacking direction of the magnetic pole tooth pieces 361 is a direction that intersects with the arrangement direction of the magnetic pole teeth 31 . The magnetic pole tooth piece 361 includes a to-be-fitted portion 361a, a connecting portion 361b, and a plurality of protrusions 361c. The to-be-fitted part 361a forms an inverted trapezoidal cross-section. The fitted portion 361a is a portion to be the fitted portion 36a of the magnetic pole unit 36 . The protrusion 361c has a rectangular cross-section. The plurality of protrusions 361c are formed at equal pitch in the longitudinal direction of the magnetic pole tooth pieces 361 . The protrusion 361c is a portion that becomes the magnetic pole tooth 31 of the magnetic pole tooth unit 36 . The connecting portion 361b is a portion positioned between the to-be-fitted portion 361a and the protruding portion 361c in the height direction of the magnetic pole tooth piece 361 . The connecting portion 361b connects the plurality of protruding portions 361c. The magnetic pole tooth piece 361 is formed of, for example, a silicon steel plate. The connecting portion 361b is a plate-shaped member constituting a laminated portion that becomes a part of the base portion of the back yoke 3 . The protrusion 361c is a plate-shaped member constituting the magnetic pole teeth 31 . The magnetic pole tooth piece 361 is formed by integrating two plate-shaped members.

The magnetic pole tooth unit 37 is formed by stacking a plurality of magnetic pole tooth pieces 371 . The stacking direction of the magnetic pole tooth pieces 371 is a direction that intersects with the arrangement direction of the magnetic pole teeth 31 . The magnetic pole tooth piece 371 has substantially the same configuration as the magnetic pole tooth piece 361 . Hereinafter, the point that the magnetic pole tooth piece 371 is different from the magnetic pole tooth piece 361 will be mainly described. The magnetic pole tooth piece 371 includes a to-be-fitted portion 371a, a connecting portion 371b, and a plurality of protrusions 371c. The connecting portion 361b of the magnetic pole tooth piece 361 protrudes in the longitudinal direction from one end in the longitudinal direction. In contrast, the connecting portions 371b of the magnetic pole tooth pieces 371 do not protrude from both ends in the longitudinal direction in the longitudinal direction. The rest of the configuration of the magnetic pole tooth piece 371 is the same as that of the magnetic pole tooth piece 361 , so a description thereof will be omitted.

37 is a perspective view showing a configuration example of the base portion 35. As shown in FIG. The base part 35 shown in FIG. 37 is upside-down inverted from the base part 35 shown in FIG. The base part 35 forms a rectangular plate shape. The base part 35 is formed with a fitting groove 35a having a trapezoidal cross-section.

The fitted part 36a of the magnetic pole tooth unit 36 or the fitted part 37a of the magnetic pole tooth unit 37 fits into the fitting groove 35a of the base part 35 . In addition, in the base part 35 , the length in the movable direction of the mover 2 may be set to match the length in the movable direction of the magnetic pole tooth unit 36 or the magnetic pole tooth unit 37 . The base portion 35 and the magnetic pole unit 36 or the magnetic pole unit 37 are fixed as follows. After applying an adhesive to one or both of the fitting groove 35a and the fitted portion 361a or the fitted portion 371a, fitting is performed. Thereby, the base part 35 and the magnetic pole unit 36 or the magnetic pole tooth unit 37 are fixed. As a result of the above, the back yoke unit 301 or the back yoke unit 302 is formed. Then, according to the stroke of the linear motor 1, the number of back yoke units 301 is selected, and a plurality of back yoke units 301 and one back yoke unit 302 are combined, as shown in FIG. 35 . A back yoke 3 is formed. Each of the back yoke units 301 and 302 may be coupled by a known method, for example, the back surfaces of the back yoke units 301 and 302 may be fixed with a rectangular plate-like member.

In the linear motor 1 in the second modification, the magnetic pole tooth units 36 and 37 are constituted by laminating silicon steel plates (pole tooth pieces 361 and 371). In the linear motor 1, in addition to the magnetic pole teeth 31, a part of the thickness direction from the connecting portion with the magnetic pole teeth 31 of the back yoke 3 has a laminated structure. Therefore, the magnetic flux flowing to the connecting portions 361b and 371b between the adjacent magnetic pole teeth 31 is in a direction parallel to the surfaces of the magnetic pole tooth pieces 361 and 371 . The direction of the eddy current generated by the flow of magnetic flux is a direction penetrating the plate surfaces of the magnetic pole tooth pieces 361 and 371 . However, due to the spacing between the surfaces of the magnetic pole tooth pieces 361 and 371, the oxide film formed on the surface, etc., the resistance in the eddy current direction in the connecting portions 361b and 371b is larger than that in the case of not having a laminated structure. . Therefore, it becomes possible to reduce the eddy current flowing through the connecting portions 361b and 371b. Therefore, it becomes possible to further reduce the eddy current flowing through the back yoke 3 .

Further, in the second modification, the following effects reside in addition to the above-described effects in which the basic example 1 resides. Since it is possible to form the base portion 35, which is a part of the back yoke 3, of a non-magnetic material, it becomes possible to constitute it from a material having a high elastic modulus, for example, alumina. Thereby, since the rigidity of the whole back yoke 3 is increased, it is possible to reduce the deflection caused by the attraction force generated between the movable element 2 and the movable element 2 . Moreover, when the rigidity of the whole back yoke 3 exceeds the rigidity requested|required by the material of the base part 35, it becomes possible to make the back yoke 3 thin. Moreover, in the second modification, by varying the number of back yoke units 301 included in the back yoke 3 , it becomes possible to change the stroke of the linear motor 1 .

In addition, although the number of magnetic pole values 31 provided with each of the back yoke units 301 and 302 was set to five, it is not limited to that. Although it has been said that the base part 35 is provided with the one stimulation tooth unit 36 or the stimulation tooth unit 37, it is not limited thereto. Although the stimulation value unit 36 and the stimulation value unit 37 are each provided with the same number of stimulation values 31, the present invention is not limited thereto.

(Third modification of Embodiment 2)

The third modified example relates to a configuration in which the base portion 35 is a single plate in the second modified example. 38A is a side view showing another configuration example of the back yoke 3 . The back yoke 3 includes a base portion 33 , a plurality of magnetic pole tooth units 36 and a magnetic pole tooth unit 37 . The configuration of the stimulus value unit 36 and the stimulus value unit 37 is the same as in the above-described second modified example, and thus description thereof is omitted.

38B is a perspective view showing a configuration example of the base portion 33. As shown in FIG. The base part 33 shown in FIG. 38B is upside down from the base part 33 shown to FIG. 38A. The base portion 33 has a plurality of dovetail grooves (fitting grooves) 33a formed in a rectangular plate material. The shape of the dovetail groove 33a corresponds to the to-be-fitted portions 36a and 37a of the magnetic pole tooth units 36 and 37 . The back yoke 3 is fitted to the dovetail grooves 33a of the base portion 33 and the to-be-fitted portions 36a and 37a of the magnetic pole tooth units 36 and 37, and then fixed with an adhesive or the like. The base portion 33 is formed of a non-magnetic material.

In the third modified example, in addition to the above-described effect in which the basic example 1 resides, the following effects reside. It becomes possible to comprise the base part 33 which is a part of the back yoke 3 from a nonmagnetic material with a high elastic modulus, for example, alumina. Thereby, since the rigidity of the whole back yoke 3 is increased, it is possible to reduce the deflection caused by the attraction force generated between the movable element 2 and the movable element 2 .

In the above-described basic example and first to third modified examples, the space between adjacent magnetic pole teeth 31 may be filled with a non-magnetic material, for example, a resin mold or the like. As a result, the strength of the back yoke 3 is increased, and the bending of the back yoke 3 due to the suction force generated between it and the movable element 2 can be more effectively suppressed.

The base plate 32 in the above-described basic example may have a laminated structure in which a part of the magnetic pole teeth 31 in a direction opposite to the protruding direction (thickness direction) of the magnetic pole teeth 31 is formed. In other words, the magnetic pole teeth 31 (protrusions 31a, 31a), which are laminated structures, may be engaged with the recesses 32a and 32a in the laminated structure portion of the base plate 32 having a partially laminated structure. This makes it possible to suppress the eddy current caused by the magnetic flux flowing in the moving direction of the mover 2 as in the first and second modified examples.

The technical features (structural requirements) described in each embodiment can be combined with each other, and new technical features can be formed by combining them. It should be thought that embodiment disclosed this time is an illustration in every point, and is not restrictive. The scope of the present invention is not the meaning described above, it is indicated by the claims, and it is intended that all changes within the meaning and scope equivalent to the claims are included.

1 linear motor
2 mover
3 back yoke
4 Armature
21 permanent magnet
22 maintenance border
23 fixed plate
31 Stimulus value
32 base plate
33 base
34 stimulus block
35 base
36 stimulus units
37 stimulus unit
41 core
42 stimulus
43 drive coil
221 hole
301 back yoke unit
302 back yoke unit
311 pole piece
341 Stimulus Tooth Piece
361 magnetic pole
371 Stimulated Tooth

Claims (9)

A mover having a magnet arrangement in which a plurality of rectangular permanent magnets are arranged, a back yoke serving as a stator facing the mover at a distance from the mover, and facing the mover at a distance from the back yoke and an armature as a stator,
The magnetization direction of each of the plurality of permanent magnets is in the thickness direction, and the magnetization direction of the permanent magnets adjacent to each other is the opposite direction,
The armature has a plurality of magnetic pole teeth each having a driving coil wound at an equal pitch,
the back yoke has a plurality of magnetic pole values at the same position as the magnetic pole values of the armature on a surface opposite to the movable element in the moving direction of the mover;
The magnetic pole teeth of the back yoke are formed by stacking a plurality of plate-shaped members in a direction intersecting the moving direction of the movable member,
At least one of a distance between the mover and the back yoke and a distance between the mover and the armature is variable;
In the back yoke, a part of the back yoke in a direction opposite to the protrusion direction of the magnetic pole teeth from the base of the magnetic pole teeth is formed by stacking a plurality of plate-shaped members in the stacking direction of the magnetic pole teeth,
A linear motor characterized in that the plate-shaped member constituting the lamination portion of the back yoke and the plate-shaped member constituting the magnetic pole teeth are integrated.
According to claim 1,
The height of the magnetic pole value in the back yoke is 1/20 times or more and 2 times or less of the pitch of the magnetic pole values.
3. The method of claim 1 or 2,
A length of the mover is shorter than a length of the armature and shorter than a length of the back yoke.
delete According to claim 1,
The magnetic pole area of the magnetic pole value in the back yoke is 0.9 to 1.1 times the magnetic pole area of the magnetic pole value in the armature, and the distance between the mover and the back yoke is the same as the distance between the mover and the armature, or big
Linear motor, characterized in that.
delete According to claim 1,
The plurality of plate-shaped members are formed by applying insulation treatment to the laminated surface.
Linear motor, characterized in that.
According to claim 1,
The mover has a holding member for holding the magnet arrangement, and the holding member has a plurality of holes into which each of the plurality of permanent magnets is inserted.
9. The method of claim 8,
The movable member has a plate-shaped base material to which the holding member and the plurality of permanent magnets are adhesively fixed.

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