JP2005039941A - Cylindrical linear motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical linear motor that can reduce the cogging thrust of the motor. <P>SOLUTION: The cylindrical linear motor 10 comprises a needle 11 composed of an armature core 12 and an armature coil 13, and a stator 16 arranged with a plurality of permanent magnets 17. In the linear motor, a sintered material is used in the armature core 12, the permanent magnet 17 of the armature core 12 or the stator 16 is subjected to skewing, and steel dummy teeth 14b are arranged at the foremost end or the rearmost end of the armature core 12 in its traveling direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cylindrical linear motor used in a machine tool, a semiconductor manufacturing apparatus, or the like.

As a cylindrical linear motor, one constituted by a mover composed of an armature core and an armature coil and a stator having a large number of permanent magnets is known (for example, see Patent Document 1).
JP-A-8-275497

The cylindrical linear motor described in Patent Document 1 has a compact and compact overall structure and is easy to assemble. The cylindrical linear motor has a rod-shaped stator having a propulsion field magnet and is fitted on the field magnet. The armature coil and the mover mounted with the hall element constitute a linear motor, and a step portion is formed on the surface of the stator at the field magnet portion so that the hall element is disposed opposite to the stator and the mover is attached to the mover. The magnetic sensor is disposed so as to face and approach the magnetized portion.
However, this cylindrical linear motor has a stepped part on the stator surface and the Hall elements are arranged close to each other. Therefore, the gap between the stator and the mover cannot be narrowed, and machining is complicated. There were drawbacks such as.
4A and 4B show a conventional cylindrical linear motor that solves the above-described drawbacks. FIG. 4A is a front view, FIG. 4B is a plan view, and FIG. 4C is a side view.
In the figure, reference numeral 40 denotes a conventional cylindrical linear motor, which mainly comprises a mover side 41 and a stator portion 46.
The mover 41 is an armature core 42 in which a large number of thin electromagnetic steel plates are laminated.
Reference numeral 43 denotes an armature coil, and the armature coils are connected by soldering at the connection portion 44.
The stator 46 constitutes a stator by arranging a large number of permanent magnets 47.
Reference numeral 48 denotes a linear guide that supports the movable element directly below, thereby supporting the movable element 41. The position of the movable element 41 is detected by the linear scale 49a and the linear scale / read head 49b.

However, the conventional cylindrical linear motor 40 has a structure in which the armature coil 42 and the permanent magnet 47 are both arranged perpendicular to the thrust direction, and a cogging thrust is likely to be generated.
As a solution, it is conceivable to skew the armature coil 42, but the armature core is formed by laminating a large number of thin electromagnetic steel sheets, and it is desirable in production that the cross-sectional shape of each one is the same. There has been a problem that the armature core cannot be made into a complicated core shape that skews the armature core.
Further, although the mover 41 is supported by a linear guide 48 disposed below the mover 41, this configuration has a problem that rigidity is low and yawing occurs.
Furthermore, there is a problem that the positioning accuracy is not good because the number of parts from the stage surface 45 of the mover 41, which requires positioning accuracy, to the linear scale / read head 49b that actually detects the position is large.
In addition, the connection work at the connection part 44 for soldering a large number of armature coils 43 is very time-consuming work and lacks reliability such as disconnection due to miswiring and vibration.
Next, with this configuration, dust and foreign matter are likely to accumulate on the surface of the permanent magnet 47 of the stator 46 and the gap between the magnets, and there is a risk of motor failure particularly when metal pieces or the like adhere.
In addition, the permanent magnets 47 need to be accurately arranged at equal intervals in the thrust direction, but are bonded one by one using a positioning jig, which is a laborious operation.
Next, the linear motor 40 is often replaced with a linear motion guide device using a conventional ball screw in a machine tool. Therefore, the stator 46 is very long, and the stator 46 in which a large number of permanent magnets 47 are arranged. The shaft has a problem of large deflection due to its own weight, which adversely affects the characteristics of the motor. Particularly in a semiconductor device, high-accuracy positioning is required, and as a result, the temperature rise of the device is severely limited. However, there is a problem that the temperature specification cannot be satisfied due to heat generation of the mover 41 provided with the armature coil 43. there were.

FIG. 5 shows another type of conventional cylindrical linear motor, in which (a) is a front view, (b) is a plan view, and (c) is a side view.
In the figure, reference numeral 50 denotes another type of cylindrical linear motor, which mainly comprises a mover side 51 and a stator portion 56. The armature side 51 is an armature core 52, which is composed of two types, a center laminated core 53 and a both-ends laminated core 54. Each of the center laminated core 53 and the both end laminated cores 54 is made of a thin plate such as an electromagnetic steel plate, and in order to form the armature core 52, a certain number of center laminated cores 53 are laminated, and a certain number of both end laminated cores 54 are further laminated. It is created by stacking and aligning each. An armature coil 55 is disposed between the armature cores 52 and 52.
The stator portion 56 constitutes a stator by arranging a large number of permanent magnets 57.
Reference numeral 58 denotes a linear guide which supports the movable element 51, and detects the position of the movable element 51 by a linear scale 59a and a linear scale / read head 59b.
However, the armature core 52 of this type of cylindrical linear motor 50 has a configuration using two types of laminated cores, that is, a central laminated core 53 and a double-ended laminated core 54, and can be easily positioned and overlapped. There was a problem that it was not possible to spend a lot of time on core production.
In addition, since there are two types of laminated cores, two types of punching die, positioning jig and the like are necessary, and there is a problem that a large amount of cost is required for core production.
Furthermore, since the lamination direction of the thin electromagnetic steel plates is perpendicular to the direction of the magnetic path of the magnetic circuit, there is a problem that eddy current is generated in the electromagnetic steel plates and the motor efficiency is deteriorated.
Therefore, the present invention has been made in view of such problems, and while reducing the cogging thrust, reducing the yawing of the mover, improving the accuracy of position detection, improving the motor characteristics, The purpose is to provide a cylindrical linear motor that can reduce the eddy current and improve the motor efficiency by reducing the eddy current by simplifying the configuration of the child core, thereby reducing the manufacturing time and reducing the manufacturing cost. To do.

In order to solve the above problem, the invention described in claim 1 is a cylindrical linear motor including a mover including an armature core and an armature coil, and a stator in which a large number of permanent magnets are arranged. It is characterized by using a sintered material for the armature core.
According to a second aspect of the present invention, in the cylindrical linear motor according to the first aspect, the armature core or the permanent magnet of the stator is skewed.
Next, the invention according to claim 3 is the cylindrical linear motor according to claim 1 or 2, wherein a steel dummy tooth is arranged at the foremost end or the rearmost end in the traveling direction of the armature core. It is a feature.
According to a fourth aspect of the present invention, in the cylindrical linear motor according to any one of the first to third aspects, the two linear guides arranged on both sides of a plane perpendicular to the moving direction of the mover The movable element is supported, and a linear scale for position detection is provided inside at least one of the linear guides.
According to a fifth aspect of the present invention, in the cylindrical linear motor according to any one of the first to fourth aspects, a notch groove is provided in an upper portion of the armature core, and a connection substrate is provided in the notch groove. It is characterized by the arrangement.
A sixth aspect of the present invention is the cylindrical linear motor according to any one of the first to fifth aspects, wherein a spacer made of a nonmagnetic material is disposed between the permanent magnets.
A seventh aspect of the present invention is the cylindrical linear motor according to any one of the first to sixth aspects, wherein the gap between the movable element and the stator is cleaned, for example, a neoprene sponge or the like. A wiper made of the elastic material is provided on the movable element side.
The invention described in claim 8 is characterized in that, in the cylindrical linear motor according to any one of claims 1 to 7, a hollow shaft is used as a stator.

The invention according to claim 9 is characterized in that the armature core is configured by alternately arranging the central laminated core and the integral yoke.
Further, the invention described in claim 10 is characterized in that several uneven portions are provided in each of the central laminated core and the integral yoke constituting the armature core, and the uneven portions are joined as a reference.

As described above, according to the invention of the cylindrical linear motor according to claim 1, since the sintered material is used for the armature core, the armature coil can be easily made into a shape in which the armature coil is skewed. The cogging thrust can be reduced and excellent motor characteristics can be obtained.
In the invention according to claim 2, since the armature core or the magnet of the stator according to claim 1 is skewed, the cogging thrust of the motor can be further reduced, and the motor characteristics are improved.
Next, according to the cylindrical linear motor of the third aspect, since dummy teeth made of sintered material are added to both ends of the armature core, the cogging thrust of the motor can be similarly reduced. And motor characteristics are improved.
According to the invention described in claim 4, the movable element is supported by two linear guides arranged on both sides, and a linear scale for position detection is provided inside at least one of the linear guides. Since they are integrated, there is an effect that the rigidity of the guide is increased, yawing of the mover can be reduced, and motor characteristics and position detection accuracy can be improved.

According to the invention described in claim 5, since the wiring board is arranged in the notch groove provided on the upper part of the armature core, the productivity is good, and the entire groove is resin-molded after the connection. Since it becomes strong against vibration during motor operation, there is an effect that reliability can be improved.
According to the sixth aspect of the present invention, since the non-magnetic material spacers are arranged between the permanent magnets, the permanent magnets are accurately arranged at equal intervals to improve productivity. There is an effect that can be.
According to the seventh aspect of the present invention, since the wiper made of an elastic material such as neoprene sponge is provided in the gap portion between the stator and the stator, dust accumulated on the permanent magnet Since foreign matters can be removed and stable operation of the linear motor can be guaranteed, there is an effect that the reliability of the motor is increased.
According to the invention described in claim 8, a hollow shaft is used for the stator, and the motor can be cooled by flowing a cooling liquid therethrough, and the mass of the shaft is also reduced. As a result, there is an effect that excellent motor characteristics can be obtained.
According to the invention described in claim 9, since the armature core is formed by alternately arranging the central laminated core and the integral yoke, the working time can be shortened, the manufacturing cost can be reduced, and the sintered material can be reduced. By using the integrated yoke made of steel, the magnetic path of the magnetic circuit is not obstructed, so that an eddy current can be reduced.
Further, according to claim 10, the central laminated core and the integral yoke are provided with several uneven portions, respectively, and by joining the uneven portions as a reference, alignment and the like can be easily performed, There is an effect that the production time can be shortened.

Hereinafter, the present invention will be described in detail with reference to the drawings.
(First embodiment of the first invention)
FIG. 1 is a cylindrical linear motor according to a first embodiment of the first invention of the present application, in which (a) is a front view, (b) is a plan view, and (c) is a side view.
In the figure, 10 is a cylindrical linear motor according to the present invention, 11 is a mover, 12 is an armature core, 13 is an armature coil, 14a is a wiring board, 14b is a dummy tooth, 14c is a wiper, 14d is a stage surface, Reference numeral 16 is a stator, 17 is a permanent magnet, 18 is a linear guide, 19a is a linear scale, and 19b is a linear scale read head.
The armature core 12 is formed by integrally forming each block using a sintered material, and the generated eddy current can be suppressed smaller than that obtained by laminating conventional electromagnetic steel sheets, thereby reducing motor loss and improving efficiency. Can be raised.
As a result, the armature core 12 that can only be formed in a simple shape can be formed into a complicated shape, so that the armature coil 13 is skewed.
Accordingly, it is difficult for cogging thrust to be generated between the armature coil 13 and the permanent magnet 17, and excellent motor characteristics can be obtained.

Furthermore, 14b is the dummy teeth made from steel materials, and the thrust which cancels cogging similarly can be obtained by arrange | positioning at the both ends of the armature core 12. FIG.
A linear guide 18 is configured to support the mover 11 from both sides. As a result, the rigidity is increased, the yawing of the mover 11 is reduced, and a high-precision and smooth movement can be obtained. The linear guide 18 is chamfered, and a linear scale 19a is directly attached to the surface for integration.
Reference numeral 19b denotes a linear scale read head. With this configuration, the accuracy of position detection of the mover 11 can be improved.
Moreover, the connection board | substrate 14a is arrange | positioned in the notch groove provided in the upper part of the armature core 12, Thereby, positioning and connection operation | work of each armature core 12 can be performed easily. The notch groove in which the wiring board 14a is arranged is resin-sealed as a whole, and is strong against vibration during motor operation, thereby preventing disconnection.
Further, spacers 16a made of a non-magnetic material are disposed between the permanent magnets 17 to perform positioning, thereby facilitating the work of arranging the permanent magnets 17 at equal intervals with high accuracy.
Next, a wiper 14c made of neoprene sponge, which is an elastic material, is provided in the gap between the mover 11 and the stator 16, and dust and foreign matter accumulated on the permanent magnet 17 of the stator 16 can be removed. Stable operation of the linear motor 10 can be guaranteed.
Furthermore, the hollow shaft 16b is used for the stator 16, and the permanent magnet 17 whose characteristics are deteriorated due to a temperature rise can be cooled by flowing a cooling liquid therethrough. In particular, strict temperature specifications required for semiconductor manufacturing equipment and the like can be satisfied.
This cooling liquid can also prevent vibration during motor operation, and also reduce the mass of the shaft, so that the amount of deflection is reduced and excellent motor characteristics can be obtained.

(Second embodiment)
FIG. 2 is a cylindrical linear motor according to the second embodiment, wherein (a) is a front view, (b) is a plan view, and (c) is a side view.
In the figure, 20 is a cylindrical linear motor according to the present invention, 21 is a mover, 22 is an armature core, 23 is an armature coil, 24a is a wiring board, 24b is a dummy tooth, 24c is a wiper, 24d is a stage surface, 26 is a stator, 27 is a permanent magnet, 28 is a linear guide, 29a is a linear scale, and 29b is a linear scale read head.
In addition to applying a skew to the armature coil in the first embodiment, the stator 26 has a structure in which the permanent magnet 27 is also skewed, thereby further reducing the cogging thrust of the motor. be able to.
In addition, linear scales 29a are arranged on the linear guides 28 on both sides of the movable element 21, and the position is detected by the linear scale / read head 29b. As a result, the values detected by the two sensors can be canceled, and the accuracy of positioning of the mover can be further improved.

3A and 3B are diagrams showing the configuration of the cylindrical linear motor according to the second invention of the present application, in which FIG. 3A is a front view, FIG. 3B is a plan view, and FIG. 3C is a side view.
In the figure, 30 is a cylindrical linear motor according to the second invention of the present application, 31 is a mover, 32 is an armature core, 33 is a central laminated core, 34 is an integral yoke made of sintered material, 35 is an armature coil, Reference numeral 36 denotes a stator portion, 37 a permanent magnet, 38 a linear guide, 39 a a linear scale, and 39 b a linear scale read head.
The armature core 32 includes a central laminated core 33 formed by punching electromagnetic steel sheets into a ring shape and then laminated to a certain thickness, and an integrated yoke 34 made of a sintered material that is also integrally formed into a ring shape. Are arranged alternately.
As shown in FIG. 5, the stacking work of the thin plates, which took a very long time, is reduced in the workability because the number of laminated cores is one kind in this way. Since only one type is required, production costs can be reduced.
Furthermore, since the sintered yoke 34 made of a sintered material does not disturb the magnetic path of the magnetic circuit, eddy current can be reduced.

In addition, as shown in a partially enlarged view A of FIG. 3A, the electromagnetic steel sheet constituting the center laminated core 33 is provided with several V-shaped or semicircular irregularities 33a by pressing, In addition, unevenness 34 a having the same shape is also formed on both end surfaces of the integral yoke 34.
By joining the concave and convex portions as a reference, positioning can be easily performed in the process of stacking a large number of thin plates of the central laminated core 33 and joining the central laminated core 33 and the integral yoke 34, and in a short time The child core 32 can be manufactured.
The armature coil 35 is disposed between the armature cores 32 and 32, and the stator portion 36 includes a large number of permanent magnets 37 to constitute a stator.
Reference numeral 38 denotes a linear guide which supports the movable element 31. The position of the movable element 31 is detected by the linear scale 39a and the linear scale / read head 39b.
As described above, according to the second invention of the present application, the armature core is configured by alternately arranging the central laminated core and the integral yoke, so that the working time can be shortened and the manufacturing cost can be reduced.
Furthermore, by using an integral yoke made of a sintered material, the magnetic path of the magnetic circuit is not obstructed, and eddy currents can be reduced.
In addition, since the central laminated core and the integral yoke constituting the armature core are each provided with several uneven portions, and the uneven portion is used as a reference, the position can be easily adjusted and the armature core can be easily aligned. The production time of can be further reduced.

It is a figure of the cylindrical linear motor which concerns on 1st Embodiment of this-application 1st invention, (a) is a front view, (b) is a top view, (c) is a side view. It is a figure of the cylindrical linear motor which similarly shows 2nd Embodiment, (a) is a front view, (b) is a top view, (c) is a side view. It is a figure of the cylindrical linear motor which concerns on this invention 2nd invention, (a) is a front view, (b) is a top view, (c) is a side view. It is a figure of the conventional cylindrical linear motor, (a) is a front view, (b) is a top view, (c) is a side view. It is a figure of another type of conventional cylindrical linear motor, (a) is a front view, (b) is a top view, (c) is a side view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cylindrical linear motor 11,21,31 needle | mover 12,22,32 armature core 13,23,33 Armature coil 14a, 24a Connection board 14b, 24b Dummy teeth 14c based on 1st Embodiment of this invention 1st invention 24c Wiper 14d, 24d Stage surface 16, 26, 36, Stator 17, 27, 37 Permanent magnet 18, 28, 38 Linear guides 19a, 29a, 39a Linear scales 19b, 29b, 39b Linear scale / read head 20 1 Cylindrical linear motor 30 according to the second embodiment of the present invention Cylindrical linear motor 33 according to the second invention of the present application Central laminated core 33a Uneven portion 34 of the central laminated core Sintered material integrated yoke 34a Sintered material integrated Yoke irregularities

Claims (10)

A cylindrical linear motor comprising a mover composed of an armature core and an armature coil, and a stator having a large number of permanent magnets arranged therein, and a cylinder characterized by using a sintered material for the armature core Linear motor. The cylindrical linear motor according to claim 1, wherein a skew is applied to the permanent magnet of the armature core or the stator. 3. The cylindrical linear motor according to claim 1, wherein a steel dummy tooth is disposed at a foremost end or a rearmost end in the traveling direction of the armature core. Two linear guides arranged on both sides of a plane perpendicular to the moving direction of the mover support the mover, and a linear scale for position detection is provided inside at least one of the linear guides. The cylindrical linear motor according to any one of claims 1 to 3. The cylindrical linear motor according to any one of claims 1 to 4, wherein a cutout groove is provided in an upper portion of the armature core, and a wiring board is disposed in the cutout groove. The cylindrical linear motor according to claim 1, wherein a spacer made of a nonmagnetic material is disposed between the permanent magnets. The cylinder according to any one of claims 1 to 6, wherein a wiper made of an elastic material for cleaning a gap portion between the mover and the stator is provided on the mover side. Linear motor. The cylindrical linear motor according to claim 1, wherein a hollow shaft is used as the stator. In a cylindrical linear motor composed of an armature core, a mover composed of an armature coil, and a stator having a large number of permanent magnets, the armature core is composed of a laminated core and an integral yoke. Cylindrical linear motor. The cylindrical linear motor according to claim 9, wherein the laminated core and the integral yoke are each provided with several uneven portions, and the uneven portions are joined based on the uneven portions.

Images