JP5460991B2 - Linear motor stator - Google Patents

Description

  The present invention relates to a stator for a linear motor used in industrial machines such as machine tools.

  Conventionally, in an industrial machine such as a machine tool, a linear motor has been used as a means for realizing high speed and high accuracy. Among such linear motors, especially in long-stroke machines, the use of expensive permanent magnets on the mover side reduces the amount of permanent magnets used and realizes cost reduction of the motor. Is disclosed in Patent Document 1.

  4A and 4B show a conventional linear motor disclosed in Patent Document 1, in which FIG. 4A is a cross-sectional structure diagram, and FIG. 4B is a diagram showing a magnetization direction of a permanent magnet. In FIG. 4A, reference numeral 12 denotes a stator which is fixed to, for example, a machine tool bed. The stator 12 is made of a soft magnetic material such as an electromagnetic steel plate, and the stator salient poles 10 are formed on the surface with a pitch P. Reference numeral 11 denotes a mover, which is fixed to a table of a machine tool, for example, and is supported so as to be movable in the X-axis direction of FIG. 4 by a rolling guide or the like provided between the bed of the machine tool and the table. Similarly to the stator 12, the mover 11 is formed by laminating electromagnetic steel plates, for example. Further, 13, 14 and 15 are teeth of U, V and W phases constituting the mover 11, and each is shifted by a (P / 3) pitch corresponding to an electrical angle of 120 ° relative to the X-axis direction. Has been placed.

  16, 17, and 18 are U, V, and W-phase AC windings wound around each tooth, and 19 is a permanent magnet that is alternately arranged in the order of N, S, N,. Each phase tooth has three sets of permanent magnets arranged at a pitch P, where N and S are a set, as shown in FIG. Reference numeral 20 denotes a mover magnetic yoke, 21 denotes a stator magnetic yoke, and 22 denotes a state of magnetic flux in a state where a current is applied to the AC windings 16, 17, and 18 in the direction of U → VW. The AC windings 16, 17, and 18 are connected to star windings in which the U phase, V phase, and W phase are connected at neutral points as shown in FIG.

  Now, when a current is applied to the AC windings 16, 17, and 18, the three-phase teeth are excited in the positive or negative direction in the Y-axis direction. At this time, among the permanent magnets 19, the magnetic flux of the permanent magnets arranged in the same magnetic direction as the excitation direction of the AC winding is strengthened, and the magnetic flux of the permanent magnets arranged in the magnetic direction opposite to the excitation direction is weakened. Therefore, the teeth of each phase are excited to either the N pole or the S pole, and become one magnetic pole having a large N pole or S pole. And the magnetic flux which passed each tooth | gear and the stator side comprises a closed loop as shown by 22 of FIG. At this time, a magnetic attraction force corresponding to the position is generated in the mover and the stator, so that a thrust is generated in the mover.

  The flow of magnetic flux will be described in more detail. If the current flows in the U → V, W phase, that is, the AC winding 16 is in the winding direction shown in the figure and the AC windings 17 and 18 are in the opposite direction to the winding direction shown in the figure, the teeth 13 in FIG. At the poles, the teeth 14 and 15 become N poles, and as shown by the magnetic flux 22, the magnetic flux flows from the teeth 13 to the teeth 14 and 15, and then passes through the stator 12 and returns to the teeth 13 again. To do. Then, a magnetic attraction force acts on the mover 11 in the X-axis direction to generate a thrust.

  The feature of the conventional linear motor shown in FIG. 4 is that an expensive permanent magnet is arranged on the side of the mover. Therefore, when the stroke of the linear motor becomes long, the amount of permanent magnet used can be reduced. The cost reduction can be realized. In addition, since a plurality of magnetic poles of each phase composed of the permanent magnet 19 of the mover are excited by one winding, the winding length is shortened, and the electric current flows through the winding due to the electrical resistance. There is also a characteristic that loss, so-called copper loss, is reduced and efficiency is increased.

  In addition to the star winding shown in FIG. 5, a Δ winding can be adopted as a method for connecting the AC winding.

  FIG. 6 is a view showing a general stator 12 according to the prior art. In order to reduce the eddy current generated in the stator, the magnetic steel sheets are laminated. In addition, the magnetic steel sheet is fixed with an adhesive to prevent the stator from being deformed by the magnetic attractive force generated between the mover and the motor characteristics being deteriorated or the mover and the stator being in contact with each other. To increase rigidity.

JP 2005-185061 A

  However, the conventional linear motor stator as described above has the following problems.

  Since the surface of each laminated steel sheet is magnetically coated, the adhesive strength is weak and cannot be used with a naturally curable adhesive such as an anaerobic adhesive. Therefore, it is common to use an epoxy thermosetting adhesive or an electrical steel sheet with an adhesive coat that has been previously coated with an adhesive. The stator laminated with the adhesive is placed in a furnace at about 120 ° C. to 200 ° C. for a certain period of time and cured.

  Due to this thermosetting operation, the stator 12 is warped as shown in FIG. The reason is that the stator salient poles are provided on the surface of the stator that faces the mover, and the back surface on the opposite side is flat. Therefore, when heat is applied, the thermal stress generated on both surfaces differs. Because. When the stator is warped in this way, the air gap with the mover is not uniform, making it difficult to check the air gap after assembly. For this reason, the assembly accuracy is lowered, the air gap is partially widened, and the magnetic resistance of the widened air gap is increased, so that the magnetic flux density is lowered and the desired thrust cannot be obtained.

  Moreover, in order to eliminate this warp, the upper surface of the salient pole of the stator can be additionally processed into a flat surface. However, the 0.3 mm generated at the corner of the stator salient pole by press working of the electromagnetic steel sheet by processing. Since there is no such R portion, the permeance change in this portion becomes steep and the motor ripple increases. In addition, since the stator surface is electrically contacted with the adjacent magnetic steel sheets, an eddy current is generated and a motor loss occurs. In addition, it is difficult to implement due to increased costs due to an increase in processing steps.

In the linear motor according to the present invention, in the stator of the linear motor, which is arranged with a predetermined interval along the moving direction of the mover, and has a plurality of stator salient poles having the same width at the pitch P on the surface. , salient pole shape and the same shape of said stator salient poles, is disposed on the reverse side of the opposing surface opposite to said movable element of said stator, said salient poles disposed on back surface the recess, characterized that you have been fitted into the stator auxiliary yoke having a convex portion so as to fill the recess.

  Further, the stator is configured by laminating electromagnetic steel sheets, and the laminated electromagnetic steel sheets are bonded and fixed to each other.

  In a stator of a linear motor that is arranged with a predetermined interval in the moving direction of the mover and has a plurality of stator salient poles having the same width at the pitch P on the surface, the shape of the stator salient pole is substantially the same. By arranging the salient poles of the same shape on the back surface opposite to the surface facing the mover, it is possible to reduce the warpage of the stator during adhesive hardening, so the air gap between the mover and the stator is kept uniform. The desired motor thrust can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating the stator of the linear motor according to the first embodiment. Reference numeral 30 denotes a stator according to the present invention, which is formed by laminating and bonding a plurality of electromagnetic steel sheets. In the stator 30, a stator salient pole 10a is disposed on the surface facing the mover, and a salient pole 10b having the same shape as the stator salient pole 10a is also disposed on the back surface on the opposite side. The mover and other symbols are the same as those in FIG.

  In the stator of the linear motor according to the first embodiment, salient poles having substantially the same shape are disposed on the opposing surface of the mover and the opposite back surface. Therefore, even if the temperature is raised during the adhesion hardening of the electromagnetic steel sheet, the thermal stress is uniformly applied on both sides, so that the warp of the stator is eliminated.

  The stator magnetic yoke 32 of the stator 30 has the same width Hy as the stator magnetic yoke 21 of FIG. This is because when the width Hy of the stator magnetic yoke is reduced, the magnetic saturation limit of the magnetic flux 22 generated in the stator magnetic yoke portion is lowered, and the peak thrust is reduced. Therefore, the width H1 of the stator 30 is increased by the height Hc of the salient pole 10b as compared with the width H4 of the stator of the conventional linear motor of FIG.

  FIG. 2 is a diagram illustrating the stator of the linear motor according to the second embodiment. Reference numeral 35 denotes a stator of a linear motor according to the present invention, in which a stator salient pole 36a is disposed on the surface facing the movable element, and a salient pole 36b having the same shape as the stator salient pole 36a is disposed on the back surface on the opposite side. . A stator auxiliary yoke 37 having a convex portion is fixed by adhesion or the like so as to fill the concave portion of the salient pole 36b. The mover and other symbols are the same as those in FIG.

  The stator salient pole 36a and salient pole 36b of the second embodiment are the same as those of the first embodiment, but the stator auxiliary yoke 37 is fitted to the salient pole 36b. The stator auxiliary yoke 37 fitted in the recess 36b can be passed through. Therefore, the width Hy2 of the stator magnetic yoke 38 of the stator 35 can be the same as the width Hy of the stator magnetic yoke 21 of FIG. 4, and the width H2 of the stator 35 is also equal to the width H1 of the stator 30. Can be the same.

  Thus, although the stator of the linear motor of Example 2 is the same size as the conventional linear motor, the stator 35 has substantially the same shape on the surface facing the mover and the back surface on the opposite side. Therefore, even if the temperature is raised during the adhesion hardening of the electromagnetic steel sheet, the thermal stress is applied uniformly on both sides, and the warp of the stator is eliminated.

  The stator auxiliary yoke 37 includes a salient pole 39 that is a convex portion and a connecting portion 40 that is connected to the salient pole 39. Even if the connecting portion 40 is not provided, the same effect as in the second embodiment is obtained. Is obtained. However, when the stator auxiliary yoke 37 is integrated, the working time is shortened compared to the work of fitting each of the salient poles 39 into the recess of the stator salient pole 36b when the stator auxiliary yoke 37 is fixed to the stator 35. it can.

  Further, the stator auxiliary yoke 37 can be manufactured by using a remaining material such as an electromagnetic steel plate from which the stator salient pole 36b is punched. Usually, the width of the salient pole 39 of the stamped stator auxiliary yoke 37 is set to the stator. Since it becomes larger than the width of the salient pole 36b, the fitting becomes difficult. For this reason, if the salient pole 36b and the salient pole 39 are trapezoidal, they can be easily fitted.

  FIG. 3 shows a case where the present invention is applied to a magnetic attraction force canceling type linear motor. The linear motor shown in FIG. 1 is folded around a central axis 63 as an axis of symmetry. Since the magnetic attractive force generated in SIDE-A and SIDE-B is the same magnitude and opposite in direction, the magnetic attractive force is canceled out. In the magnetic attraction force canceling type, since the magnetic attraction force of the motor is not transmitted to the attached device, the life of the guide of the device to which the linear motor is attached can be extended, and deformation of the device due to the magnetic attraction force can be prevented.

  Also in the magnetic attraction force cancellation type of FIG. 3, since the stator structure is the same as in the second embodiment, the same effects as in the second embodiment can be obtained. Of course, the same structure as that of the first embodiment may be adopted.

  In the above description, the salient pole having substantially the same shape as that of the stator salient pole is described as being disposed on the back surface of the stator opposite to the surface facing the mover. Here, it is preferable that the two substantially have the same shape. However, in practice, even if they are not exactly the same shape, if they are the same shape to some extent, When the temperature is raised at the time of adhesive curing, the thermal stress is applied almost uniformly on both sides, and the effect of eliminating the warpage of the stator is similarly achieved. That is, the shape of the stator salient poles and the shape of the back salient poles may be in a range that is considered to be substantially the same. For example, even if a part of the dimension of each part of the shape of the stator salient pole and a part of the dimension of each part of the shape of the salient pole on the back surface are different from each other, It is only necessary that the shape is the same, that is, substantially the same shape. Moreover, you may provide a difference in both shapes according to the necessity degree of the effect of equalization of thermal stress. For example, in FIG. 1 and the like, the rectangular salient poles that are the same as the rectangular shape of the stator salient poles are arranged on the back surface, but depending on the necessity of the effect of thermal stress, Can be appropriately modified.

  The application of the stator of the linear motor according to the present invention is not limited to the linear motor of the principle disclosed here, but may be a stator having a stator salient pole and configured by laminating electromagnetic steel plates. Even if the principle of the linear motor is different, the same effect can be obtained.

It is a figure which shows Example 1 of the linear motor which concerns on this invention. It is a figure which shows Example 2 of the linear motor which concerns on this invention. It is a figure which shows the case where this invention is applied to a magnetic attraction force cancellation type | mold linear motor. It is a figure which shows the stator of the conventional linear motor. It is a figure which shows the alternating current winding of a linear motor. It is a figure which shows the stator of the conventional linear motor. It is a figure which shows the mode of a deformation | transformation in the stator of the conventional linear motor.

Explanation of symbols

  10, 10a, 36a Stator pole, 10b, 36b Salient pole, 11 Movable, 12, 30, 35 Stator, 13, 14, 15 Teeth, 16, 17, 18 AC winding, 19 Permanent magnet, 22 Magnetic flux 37 Stator auxiliary yoke.

Claims (2)

In a stator of a linear motor that is arranged with a predetermined interval along the moving direction of the mover and has a plurality of stator salient poles on the surface at intervals of a pitch P,
Salient pole shape and the same shape of said stator salient poles, the recess of the well on the back of the opposing surface opposite to the movable element is arranged, said salient poles disposed on said back surface of said stator the linear motor stator, characterized that you have stator auxiliary yoke having a convex portion is fitted so as to fill the recess. The stator is constructed by laminating electromagnetic steel plates, the electromagnetic steel plates stacked, the linear motor stator according to claim 1, characterized that you have been bonded respectively.

Images