JP2007174803A - Linear motor and method of manufacturing stator of linear motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear motor which is devised to improve the production efficiency and reduce the cost by preventing the occurrence of flexure of a stator by lightening the stator, and also by reducing parts count. <P>SOLUTION: In the linear motor which is provided with the above stator 1 that is constituted by stacking/arranging a plurality of permanent magnets 7 and also is extended in shaft form, and a moving member equipped with a coil which is installed shiftably on the peripheral side of the stator 1, the stator 1 is composed of a hollow pipe, the above plurality of permanent magnets 7 which are stacked/arranged within the hollow pipe, and a pair of end caps 11 which are arranged each at both ends of the plurality of permanent magnets and are fixed to the hollow pipe. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to, for example, a linear motor used in a precision positioning system and a linear motor stator manufacturing method for manufacturing such a linear motor stator, and in particular, to reduce the weight of the stator and improve the production efficiency. It relates to something devised so that it can be planned.

  A linear motor capable of non-contact driving is suitable as a driving mechanism for a precision positioning device, for example. Conventional linear motors and actuators using such linear motors are configured as shown in FIGS. 7 and 8, for example.

  FIG. 7 is a cross-sectional view showing the configuration of the linear motor 501, and the linear motor 501 includes a stator 503 and a mover 505. The stator 503 is installed on the outer peripheral side of the nonmagnetic center shaft 507, a plurality of ring-shaped permanent magnets 509 stacked and arranged on the outer periphery of the nonmagnetic center shaft, and the plurality of permanent magnets 509. And a pair of end caps that are screwed into the nonmagnetic center shaft 507 at both side positions of the plurality of permanent magnets 509 and partially inserted and arranged in the nonmagnetic thin pipe 511. 513, 513.

  The movable element 505 includes a coil case 515 and a coil portion 517 accommodated and arranged in the coil case 515.

As shown in FIG. 8, the stator 503 is supported at both ends by support members 519 and 519. The movable element 505 is moved in the left-right direction (arrow a direction) in the figure while being guided by the linear motion guide mechanism 521. The linear guide mechanism 521 includes a pair of guide rails 523 and 523 (shown only on one side in the figure) and guide members 525 and 525 (only two on one side in the figure) that are movably engaged with the respective guide rails 523 and 523. Are shown).
In some cases, the guide rail is constituted by one guide rail.

  For example, Patent Document 1 discloses a configuration of a linear motor of the same type.

Japanese Patent Laid-Open No. 10-313566

The conventional configuration has the following problems.
First, there was a problem that the weight of the stator 503 was heavy. This is because the non-magnetic center shaft 507 is required in the configuration, and the presence of the non-magnetic center shaft 507 increases the weight of the stator 503. And there existed a problem that the bending became large because the weight of the stator 503 was heavy. FIG. 9 shows a state in which the stator 503 is bent. As indicated by the phantom line in FIG. 9, the central portion is bent by the amount of deflection δ.
Further, if the stator 503 is bent, there is a concern about contact between the stator 503 and the coil portion 517 of the movable element 505, and there is a possibility that a healthy operation as a linear motor is impaired.
Further, since the weight of the stator 503 is increased, the weight of the actuator incorporating the stator is also increased.
In addition, the length of the nonmagnetic center shaft 507 used for the stator 503 varies depending on the stroke specifications. Therefore, a plurality of types of nonmagnetic center shafts 507 having different lengths must be prepared. There was a problem that the production efficiency was lowered.
Further, since the number of parts of the stator 503 is large, there is a problem that it is difficult to reduce the cost.

  The present invention has been made on the basis of these points, and the object of the present invention is to prevent the occurrence of bending of the stator by reducing the weight of the stator, and to reduce the number of parts, thereby reducing the production efficiency. An object of the present invention is to provide a linear motor and a linear motor stator manufacturing method devised so as to improve the cost and reduce the cost.

In order to achieve the above object, the linear motor according to claim 1 of the present invention is formed by laminating and arranging a plurality of permanent magnets, and can be moved to the outer peripheral side of the stator and a stator extended in a shaft shape. In the linear motor comprising a mover provided with a coil, the stator includes a hollow pipe, a plurality of permanent magnets stacked and arranged in the hollow pipe, and the plurality of permanent magnets. It is characterized by comprising a pair of end caps arranged at both ends of the magnet and fixed to the hollow pipe.
According to a second aspect of the present invention, the linear motor according to the first aspect is characterized in that the permanent magnet has a ring shape.
The linear motor according to claim 3 is the linear motor according to claim 2, wherein the ring-shaped permanent magnet is laminated and disposed on the outer periphery of the assembly center shaft during assembly, and the assembly center shaft is removed after assembly. It is characterized by being left behind.
According to a fourth aspect of the present invention, in the linear motor according to the first aspect, the permanent magnet has a solid shape.
According to a fifth aspect of the present invention, there is provided the linear motor according to any one of the first to fourth aspects, wherein the hollow pipe and the end cap are fixed by caulking.
A linear motor according to claim 6 is the linear motor according to any one of claims 1 to 4, wherein the hollow pipe and the end cap are fixed by welding.
According to a seventh aspect of the present invention, in the linear motor according to the sixth aspect, the hollow pipe and the end cap are fixed by laser welding.
According to another aspect of the stator manufacturing method of the linear motor of the present invention, a plurality of permanent magnets are stacked and arranged in the hollow pipe, and an end cap is inserted into each of the hollow pipes on both sides of the plurality of permanent magnets. -It is arranged and a plurality of permanent magnets are pressed in the axial direction via the end cap, and the hollow pipe and each end cap are fixed in this state.
A linear motor stator manufacturing method according to claim 9 is the linear motor stator manufacturing method according to claim 8, wherein a plurality of ring-shaped permanent magnets are provided on an assembly center shaft having male screw portions at both ends. Through the end caps at both side positions of the plurality of permanent magnets, insert and place them in the hollow pipe, and screw the nuts into the male threaded portions at both ends of the assembly center shaft. In this state, a plurality of permanent magnets are pressed, and in this state, the hollow pipe and the respective end caps are fixed, and then the nut is removed to pull out the assembly center shaft.
The linear motor stator manufacturing method according to claim 10 is the linear motor stator manufacturing method according to claim 8 or 9, wherein the hollow pipe and each end cap are fixed by caulking. It is what.
The linear motor stator manufacturing method according to claim 11 is the linear motor stator manufacturing method according to claim 8 or 9, wherein the hollow pipe and each end cap are fixed by welding. It is what.
A linear motor stator manufacturing method according to claim 12 is the linear motor stator manufacturing method according to claim 11, wherein the hollow pipe and each end cap are fixed by laser welding. It is.

As described above, according to the linear motor according to the present invention, a plurality of permanent magnets are stacked and arranged, and the stator is extended in the shape of a shaft, and the coil is movably installed on the outer peripheral side of the stator. The stator includes a hollow pipe, a plurality of permanent magnets stacked and arranged in the hollow pipe, and both ends of the plurality of permanent magnets. Since it is composed of a pair of end caps that are respectively disposed and fixed to the hollow pipe, the weight of the stator is reduced, the weight of the linear motor using such a stator is reduced, and such a linear motor is incorporated. The weight of the actuator can be reduced.
Further, according to the method of manufacturing a stator for a linear motor of the present invention, a plurality of permanent magnets are stacked and arranged in a hollow pipe, and an end cap is inserted into each of the hollow pipes on both sides of the plurality of permanent magnets. -Since a plurality of permanent magnets are axially pressed through the end caps and the hollow pipe and the respective end caps are fixed in that state, the desired stator can be easily manufactured. Can do.
In addition, a plurality of ring-shaped permanent magnets are passed through a center shaft having male screw portions at both ends, end caps are respectively passed at both side positions of the plurality of permanent magnets, and they are inserted and arranged in a hollow pipe. A plurality of permanent magnets are pressed through the end caps by screwing nuts to the male screw portions at both ends of the center shaft, and the hollow pipe and the respective end caps are fixed in this state, and then the nuts are removed. When the center shaft is pulled out, a stator having a configuration without the center shaft can be easily manufactured.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a side sectional view showing a manufacturing process of a stator 1 used in a linear motor according to the present embodiment. First, there is a nonmagnetic center shaft 3 for assembly, and both ends of the nonmagnetic center shaft 3 for assembly. The part is provided with male screw parts 5 and 5. The assembly nonmagnetic center shaft 3 is made of stainless steel (for example, SUS304), for example.

  A plurality of permanent magnets 7 are laminated and arranged on the outer periphery of the nonmagnetic center shaft 3 for assembly. The permanent magnet 7 has a ring shape and is laminated and arranged so as to pass through the outer periphery of the nonmagnetic center shaft 3 for assembly. The polarities of the adjacent and arranged permanent magnets 7 and 7 are arranged so that the same poles face each other. In this state, it is inserted and arranged in the nonmagnetic thin-walled pipe 9.

  End caps 11 and 11 are respectively inserted and arranged at both ends of the laminated and arranged permanent magnets 7 in the nonmagnetic thin walled pipe 9. An annular groove 13 is formed in advance at a predetermined position of the end cap 11. Further, a through hole 15 is bored at the center position of the end cap 11, and both end portions of the nonmagnetic center shaft 3 for assembly are passed through the through hole 15.

  Next, nuts 17 and 17 are screwed onto the male screw portions 5 and 5 of the nonmagnetic center shaft 3 for assembly projecting outward from the end caps 11 and 11. By tightening the nuts 17 and 17, the plurality of laminated and arranged permanent magnets 7 and the end caps 11 and 11 are pressed in close contact with each other in the axial direction.

Next, the nonmagnetic thin-walled pipe 9 and the end caps 11 and 11 are caulked. That is, the nonmagnetic thin pipe 9 and the end caps 11 and 11 are caulked at the positions of the annular grooves 13 and 13 of the end caps 11 and 11 by the caulking machine 21 as shown in FIGS.

The caulking machine 21 has the following configuration. First, there is a rotation main shaft (not shown), and three chuck claws (not shown) are attached to the rotation main shaft at intervals of 120 °. Each of these three chuck claws is configured to be movable in the radial direction. Rollers 23, 23, and 23 are attached to the three chuck claws in a rotatable state through shaft portions 25, 25, and 25, respectively.

First, the predetermined position of the stator 1 is gripped by the three rollers 23, 23, 23. The predetermined position is the position of the annular groove 13 of the end cap 11. In this state, the rollers 23, 23, 23 are moved radially inward to press the stator 1. At the same time, the rotating spindle itself is rotated. As a result, the three rollers 23, 23, 23 rotate and revolve while pressing a predetermined position of the stator 1. Thereby, a predetermined caulking is performed.
The pressing force, the number of rotations, the time, etc. during caulking are appropriately set according to the outer diameter, thickness, etc. of the nonmagnetic thin pipe 9 of the stator 1.
Incidentally, in the case of this type of caulking machine 21, the stator 1 side is configured not to rotate, and the support structure of the stator 1 is simply clamped to the extent that the rotation is prevented, so it is very simple. Things are enough.

By performing the caulking, the end caps 11 and 11 and the nonmagnetic thin pipe 9 are fixed.
Next, the stator 1 is removed from the caulking machine 21. Then, the nuts 17 on both sides are removed, and the nonmagnetic center shaft 3 for assembly is pulled out. Thereby, the stator 1 according to the present embodiment is obtained. This is shown in FIG. FIG. 3A is a side sectional view of the stator 1, and FIG. 3B is an enlarged sectional view showing a portion b of FIG. 3A.

As described above, according to the present embodiment, the following effects can be obtained.
First, the weight of the stator 1 is reduced. This is because there is no nonmagnetic center axis in the finally obtained configuration. That is, the nonmagnetic center shaft 3 for assembly is pulled out after assembly. Since the stator 1 can be reduced in weight in this way, it is possible to reduce the deflection of the stator 1 and prevent inadvertent contact between the stator 1 and the mover side. A stable operation as a linear motor can be provided.
Further, when the linear motor is incorporated in the actuator, the weight of the actuator can be reduced.
Moreover, since the number of parts constituting the stator 1 can be reduced, parts management can be facilitated and costs can be reduced.
The nonmagnetic center shaft 3 for assembly used at the time of assembly is only used at the time of assembly, and can be used repeatedly.
In addition, as for the nonmagnetic center shaft 3 for assembly used at the time of assembly, if a long one is prepared in advance so that it can correspond to the length of all specifications, one nonmagnetic center shaft 3 for assembly can be used. It becomes possible to deal with the manufacture of the stator 1 of all specifications.

Next, a second embodiment of the present invention will be described with reference to FIG. In the case of the second embodiment, the shape of the caulking portion is changed. That is, in the case of the first embodiment, the annular groove 13 is formed in the end cap 11. However, in this embodiment, the recesses 31 are formed at four orthogonal positions and the portion is used. It is something that was squeezed. Here, four caulks are used, but the number of caulks may be changed as appropriate according to the required strength.

Then, as shown in FIG. 4A, the punches 33 are used for caulking. The state after caulking is shown in FIG. Further, the configuration of the end cap 11 is shown in FIGS.
Even with such a configuration, the same effects as in the case of the first embodiment can be obtained.

Next, a third embodiment of the present invention will be described with reference to FIG. In the case of the third embodiment, the end caps 11 and 11 and the plurality of permanent magnets 7 are pressed by the separate jigs 41 and 41 without using the nonmagnetic center shaft 3 for assembly. It is caulked with a non-magnetic thin wall pipe.
In this case, since the nonmagnetic center shaft 3 for assembly is not used, the permanent magnet 7 may be solid rather than ring-shaped. In that case, the stator is heavier than a configuration in which a non-magnetic center shaft is not inserted and a ring-shaped permanent magnet is incorporated, but it is possible to create a stronger magnetic field. Can be increased.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. In the case of the first to third embodiments, the nonmagnetic thin-walled pipe 9 and the end caps 11 and 11 are fixed by caulking. In the case of the fourth embodiment, this is laser welding. It is made to connect by. That is, as shown in FIG. 6, the laser beam 53 is irradiated and welded to the boundary between the nonmagnetic thin-walled pipe 9 and the end cap 11 by the laser welding machine 51.

The above point will be described in detail. A pulsed YAG laser beam 53 is emitted from the laser beam emission port 51 a of the laser welding machine 51. In this case, since the high-energy YAG laser beam 53 is emitted in a very short time, the joint is hardly heated, and is instantaneously melted and fixed. Further, by rotating the stator 1 while continuously emitting the pulsed YAG laser beam 53, the stator 1 is hardly heated, and can be welded and joined all around.
Note that the rotational speed, pulse frequency, and the like of the stator 1 are appropriately set according to the outer diameter of the stator 1 and the required bonding strength.
Further, although a method of welding all around while rotating the laser beam emission port 51a is conceivable, the drawing and rotation device of an optical fiber cable (not shown) attached to the laser beam emission port 51a becomes complicated, and the work In consideration of safety, such as protection of the eyes of the person, the method of rotating the workpiece is preferable.

  In the case of laser welding, as already described, since a high-energy laser beam is output in an extremely short time, the joining portion is hardly heated and is convenient for the permanent magnet 7. This point will be described in detail. First, the permanent magnet 7 is vulnerable to heat, and may be demagnetized or demagnetized when exposed to high temperatures. On the other hand, in the case of normal arc welding or the like, the joint becomes very hot, and therefore the permanent magnet 7 in the vicinity of the joint may be demagnetized and demagnetized. When the permanent magnet 7 is demagnetized / demagnetized, the thrust of the linear motor is reduced. For this, for example, arc welding or the like may be performed while cooling the joint portion and the vicinity of the joint portion, but equipment such as a cooling device is required, and the welding operation becomes very difficult.

On the other hand, in the case of laser welding (for example, the pulse YAG method) as in the present embodiment, the nonmagnetic pipe 9 is thin, so even if the heat input to the joint and the vicinity of the joint is small. Can be easily joined. Further, even if the non-magnetic pipe 9 and the end caps 11 and 11 are made of different metals, they can be joined relatively easily. Further, in the case of laser welding, it is not necessary to use a welding rod, a brazing agent, or the like, so that the handling is easy. In addition, since the swelling of the outer diameter of the joint portion is small, dimensional management is easy.

The present invention is not limited to the first to fourth embodiments.
For example, the shape of the caulking portion, the configuration of the caulking machine, and the like are not limited to those illustrated, and various other configurations such as a spatula stop and swaging can be considered.

The present invention relates to a linear motor and a method of manufacturing a linear motor stator that manufactures a stator of such a linear motor, and more particularly, to reduce the weight of the stator and improve the production efficiency. For example, it is suitable for manufacturing a linear motor used in a precision positioning system and a stator of the linear motor.

It is a figure which shows the 1st Embodiment of this invention and is a sectional side view which shows the process of manufacturing the stator of a linear motor. It is a figure which shows the 1st Embodiment of this invention, and is a side view which shows a mode that the nonmagnetic thin-walled pipe and end cap of the stator of a linear motor are caulked. FIGS. 3A and 3B are diagrams showing a first embodiment of the present invention, FIG. 3A is a side sectional view showing a configuration of a stator of a linear motor, and FIG. 3B is an enlarged view of a portion b of FIG. FIG. FIGS. 4A and 4B are views showing a second embodiment of the present invention, in which FIG. 4A is a partial side sectional view showing a process of manufacturing a stator of a linear motor, and FIG. 4B is a configuration of the stator of the linear motor. FIG. 4C is a side view showing the configuration of the end cap, and FIG. 4D is a dd cross-sectional view of FIG. 4C. It is a figure which shows the 3rd Embodiment of this invention, and is a side view which shows the manufacturing process of the stator of a linear motor. It is a figure which shows the 4th Embodiment of this invention, and is a side view which shows the manufacturing process of the stator of a linear motor. It is a figure which shows a prior art example, and is a sectional side view which shows the structure of a linear motor. It is a figure which shows a prior art example, and is a sectional side view which shows the structure of the actuator incorporating a linear motor. It is a figure which shows a prior art example, and is a side view which shows a mode that the stator of the linear motor bent.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stator 3 Nonmagnetic center shaft 5 for assembly 5 Male thread part 7 Permanent magnet 9 Nonmagnetic thin-walled pipe 11 End cap 13 Annular groove 15 Through hole 21 Caulking machine 23 Roller

Claims (12)

A linear motor comprising a stator that is formed by laminating and arranging a plurality of permanent magnets and that is extended in the shape of a shaft, and a mover that is installed on the outer peripheral side of the stator and has a coil. In
The stator includes a hollow pipe, a plurality of permanent magnets laminated and arranged in the hollow pipe, and a pair of end caps arranged at both ends of the plurality of permanent magnets and fixed to the hollow pipe. A linear motor comprising: The linear motor according to claim 1,
A linear motor characterized in that the permanent magnet has a ring shape. The linear motor according to claim 2,
The linear motor is characterized in that the ring-shaped permanent magnet is laminated and arranged on the outer periphery of an assembly center shaft at the time of assembly, and is left after the assembly center shaft is removed after assembly. The linear motor according to claim 1,
A linear motor characterized in that the permanent magnet is solid. In the linear motor according to any one of claims 1 to 4,
A linear motor, wherein the hollow pipe and the end cap are fixed by caulking. In the linear motor according to any one of claims 1 to 4,
The linear motor, wherein the hollow pipe and the end cap are fixed by welding. The linear motor according to claim 6,
The linear motor, wherein the hollow pipe and the end cap are fixed by laser welding. A plurality of permanent magnets are laminated and arranged in the hollow pipe, end caps are inserted and arranged in the hollow pipes on both sides of the plurality of permanent magnets, and a plurality of permanent magnets are inserted through the end caps. The linear motor stator manufacturing method is characterized in that the hollow pipe and the respective end caps are fixed in this state by pressing in the axial direction. In the stator manufacturing method of the linear motor according to claim 8,
A plurality of ring-shaped permanent magnets are passed through a center shaft for assembly having male threaded portions at both ends, end caps are respectively passed at positions on both sides of the plurality of permanent magnets, and they are inserted and arranged in a hollow pipe. A plurality of permanent magnets are pressed through the end caps by screwing the nuts to the male screw portions at both ends of the assembly center shaft, and the hollow pipe and the respective end caps are fixed in this state, and then the nuts are fixed. The linear motor stator manufacturing method is characterized in that the center shaft for assembly is pulled out and the assembly center shaft is pulled out. In the stator manufacturing method of the linear motor according to claim 8 or 9,
A linear motor stator manufacturing method, wherein the hollow pipe and each end cap are fixed by caulking. In the stator manufacturing method of the linear motor according to claim 8 or 9,
A method of manufacturing a stator of a linear motor, wherein the hollow pipe and each end cap are fixed by welding. The linear motor stator manufacturing method according to claim 11,
The method of manufacturing a stator for a linear motor, wherein the hollow pipe and each end cap are fixed by laser welding.

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