JP2005065430A - Moving magnet type linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high precision moving magnet type linear actuator having a long lifetime in which thermal deformation of a linear guide incident to temperature rise can be suppressed by preventing transmission of heat generated from an armature winding to a linear guide rail. <P>SOLUTION: Stator of the linear actuator has a stator base 2, an armature 1, and a linear guide rail 5 having a U-shaped cross-section and arranged linearly to face the armature 1. A moving member has a linear guide block 7 sliding on the opposite inner side faces of the linear guide rail 5 through rollers, a movable table 14 being secured to the upper part of the linear guide block 7 to straddle the linear guide rail 5, and a field section consisting of a field yoke 4 and a field permanent magnet 3 and disposed oppositely to the armature 1 through a magnetic air gap above the movable table 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a linear motor that is used for various industrial machines such as an electrical component mounting apparatus, a semiconductor-related apparatus, or a machine tool, and is suitable for driving a linear motion mechanism thereof. The present invention relates to a moving magnet type linear actuator in which an armature having an armature winding as a mover is used as a stator.

Conventionally, a moving magnet type linear actuator that is used in various industrial machines such as an electrical component mounting apparatus, a semiconductor-related apparatus, or a machine tool and suitable for driving the linear motion mechanism is as shown in FIG. ing. 4A and 4B show a moving magnet type linear actuator showing the prior art, in which FIG. 4A is a plan view thereof, and FIG. 4B is a front sectional view taken along line BB in FIG. ) Corresponds to a view seen through from arrow A in (b).
4, 41 is an armature, 42 is a stator base, 43 is a field permanent magnet, 44 is a field yoke, 45 is a linear guide rail, 46 is a sensor, 47 is a linear guide block, 48 is a linear scale section, Reference numeral 49 is a stopper, 50 is a sensor lead, and 51 is a motor lead.
In the linear actuator, a field yoke 44 is provided on the back surface of the field permanent magnet 43, and the field yoke 44 serves both as a mover and a magnetic circuit. The armature 41 has a structure including a slotless coil group, and is arranged on the stator base 42 via a mover and a magnetic gap to constitute a stator. Parallel linear guide rails 45 are fixed to the stator base 42 on both sides of the armature 41, and linear guide blocks 47 that slide on the rails are arranged on the linear guide rail 45. It is fixed at the bottom of both ends. Further, a linear scale 48 constituting a linear encoder is disposed on the side surface of the mover, and a sensor 46 for detecting the linear scale is disposed on the stator base 42 so as to face the linear scale 48. ing. In this linear actuator, when the armature winding is excited, the mover moves linearly within a stroke that is the difference between the armature length and the mover length by a moving magnetic field formed by the field and the armature. (For example, see Patent Document 1).
Japanese Patent Laid-Open No. 9-266659 (Specification, page 5, FIG. 3)

However, in the prior art, since the linear guide rail 45 is arranged in the vicinity of the stator base 42 and the armature having the armature winding as a heating element, the heat generated by the armature winding is transmitted to the linear guide rail 45. Since the temperature rises, there is a problem that the thermal accuracy of the linear guide adversely affects positioning accuracy and life.
The present invention has been made to solve the above-described problems, and prevents the heat generation of the armature winding from being transmitted to the linear guide rail, and can suppress the thermal deformation of the linear guide accompanying a temperature rise. An object of the present invention is to provide a moving magnet type linear actuator with high accuracy and long life.

In order to solve the above problems, the invention of claim 1 is arranged such that the armature part is on the stator side and the field part is on the mover side, and the position of the mover in the sliding direction relative to the stator is set. In the moving magnet type linear actuator that is detected by an encoder, the stator faces the armature portion, a stator base, an armature portion fixed to the stator base and mounted with a plurality of coil groups. A linear guide rail having a U-shaped cross section, and the mover is disposed in a concave portion of the linear guide rail and on both inner side surfaces of the linear guide rail. A linear guide block that slides through a rolling element, and a movable table that is fixed to the upper part of the linear guide block and arranged so as to straddle the linear guide rail A field portion made of a field permanent magnet that is disposed opposite to the armature portion via a magnetic gap and is provided above the movable table via a field yoke, and The encoder includes an optical linear scale disposed on a side surface of the movable table, and a sensor that faces the linear scale and is disposed on the stator base side and detects the linear scale. It is an optical encoder.
According to a second aspect of the present invention, in the moving magnet type linear actuator according to the first aspect, the stator base is formed of a nonmagnetic member, and a thin silicon steel plate is provided between the armature portion and the stator base. It is characterized in that a yoke formed by laminating is arranged.
According to a third aspect of the present invention, in the moving magnet type linear actuator according to the first or second aspect of the present invention, a refrigerant conduit or a forced liquid cooling jacket is embedded in the stator base.
According to a fourth aspect of the present invention, in the moving magnet type linear actuator according to the first or second aspect, a cover that covers a side surface of the linear actuator is attached, and the cover is attached to the side on which the linear scale is attached. Further, a punching process suitable for the shape of the sensor is performed so as not to interfere with the sensor.
According to a fifth aspect of the present invention, in the moving magnet type linear actuator according to the first or second aspect, between the both end mounting portions of the linear guide and the mounting portion of the stator base on which the armature portion is disposed. Further, it is characterized in that a resin or a ceramic member is sandwiched as a heat insulating material.

According to the moving magnet type linear actuator of the first aspect of the invention, the linear guide block is slid on both inner side surfaces of the U-shaped linear guide rail on the stator side via the rolling elements. Since it has a structure with a so-called monorail structure in which a movable table having a magnetic field part is disposed so as to straddle the linear guide rail at the top, the generated heat of the armature is composed of a linear guide rail and a linear guide block By adopting a structure that is difficult to transmit to the linear guide portion, it is possible to prevent life deterioration due to temperature rise and thermal deformation. In addition, since the linear guide has a monorail arrangement, the width of the actuator can be reduced.
Further, the linear scale is disposed on the side surface of the movable table, the linear scale sensor is disposed on the stator base 2, and the mounting positions of the sensor unit and the armature stator base are separated from each other. For this reason, the influence of heat on detection accuracy can be suppressed as much as possible by adopting a structure in which heat is not easily transmitted from the armature to the sensor unit.
According to the second aspect of the present invention, the stator base is made of a nonmagnetic member, and the yoke formed by laminating thin silicon steel plates is disposed between the armature portion and the stator base. Since the eddy current generated when the magnet is driven can be reduced as compared with the case of the member, this yoke portion iron loss can be greatly reduced.
According to the third aspect of the present invention, since the refrigerant conduit or the forced liquid cooling jacket is embedded in the stator base, the armature located in the vicinity of the stator base is efficiently cooled. It is possible to reduce the temperature rise of the child portion and improve the cooling performance of the linear actuator.
According to the fourth aspect of the present invention, since the cover 13 is attached so as to cover the side surface of the linear actuator, even if a magnetic substance or a foreign object falls on the linear actuator from the outside, the gap between the mover and the stator or the linear Magnetic materials and foreign substances can be prevented from being mixed between the guides, and good measures can be taken to improve the accuracy of the linear actuator and the life of the linear guide.
According to the fifth aspect of the present invention, since the heat insulating material is provided between the both end attachment portions of the linear guide and the attachment portion of the stator base provided with the armature portion, heat transfer to the movable body is hindered. The accuracy change due to thermal expansion can be suppressed.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a moving magnet type linear actuator showing a first embodiment of the present invention, in which (a) is a plan view thereof, and (b) is a front sectional view taken along line BB of (a). Yes, (a) corresponds to the view seen through from arrow A in (b).
In FIG. 1, 1 is an armature, 2 is a stator base, 2A is a sensor holder, 3 is a field permanent magnet, 4 is a field yoke, 5 is a linear guide rail, 6 is a sensor, 7 is a linear guide block, 8 Is a linear scale unit, 9 is a stopper mechanism, 10 is a sensor lead, 11 is a motor lead, and 14 is a movable table.
The features of the present invention are as follows.
That is, the stator of the linear actuator includes a stator base 2, an armature 1 that is fixed to the stator base 2, a slotless type, and a plurality of coil groups are mounted, and a straight line that faces the armature 1. And a linear guide rail 5 having a U-shaped cross section, and the mover is disposed in a concave portion of the linear guide rail 5 and rolling elements on both inner side surfaces of the linear guide rail 5. A linear guide block 7 that slides over the linear guide block 7, a movable table 14 that is fixed to the upper portion of the linear guide block 7 and that is arranged so as to straddle the linear guide rail 5, and the armature 1 and the magnetic gap A field portion made up of field permanent magnets 3 which are arranged opposite to each other and have magnetic poles alternately arranged as N-poles, S-poles and the like via a field yoke 4 on the upper side of the movable table 14; Is
Further, the linear actuator is provided with an optical linear scale 8 disposed on the side surface of the movable table 14 and the linear scale 8 so as to face the linear scale 8 and is disposed on the stator base 2 and detects the linear scale 8. An optical encoder composed of the sensor 6 is provided. The sensor unit 6 is attached to a position away from the armature 2 attached to the stator base 2 via the sensor holder 2A.
In addition, the stator base 2 is provided with stopper mechanisms 9 before and after the linear guide rail 5 in the longitudinal direction, and serves as an overrun prevention mechanism for the movable table 14.
In such a configuration, the present linear actuator has a smaller number of field magnetic poles than the number of magnetic poles of the magnetomotive force generated in the armature portion, and the difference becomes a stroke on the movable side of the linear actuator, and performs linear movement.
Accordingly, the linear guide block 7 is slid on both inner side surfaces of the U-shaped linear guide rail 5 on the stator side via the rolling elements, and the field magnet portion is straddled over the linear guide rail 5 on the linear guide block 7. Since the movable table 14 having a so-called monorail structure is provided, the generated heat of the armature is difficult to be transmitted to the linear guide portion composed of the linear guide rail 5 and the linear guide block 7. By doing so, it is possible to prevent life deterioration due to temperature rise and thermal deformation. In addition, since the linear guide has a monorail arrangement, the width of the actuator can be reduced.
Further, the linear scale 8 is disposed on the side surface of the movable table 14, the linear scale sensor 6 is disposed on the stator base 2, and the mounting positions of the sensor unit 6 and the armature stator base 2 are separated from each other. Since the position configuration is adopted, it is possible to suppress the influence of heat on detection accuracy as much as possible by adopting a structure in which heat is not easily transmitted from the armature to the sensor unit 6.

Next, a second embodiment of the present invention will be described.
FIG. 2 is a moving magnet type linear actuator showing a second embodiment of the present invention, wherein (a) is a plan view thereof, and (b) is a front sectional view taken along line BB of (a). Yes, (a) corresponds to the view seen through from arrow A in (b).
In FIG. 2, 12 is an armature yoke, and 15 is a refrigerant conduit.
The second embodiment is different from the first embodiment as follows.
In other words, the stator base 2 is made of a nonmagnetic material, and the armature yoke 12 formed by laminating thin silicon steel plates between the armature 1 and the stator base 2 is disposed.
In addition, a forced liquid cooling refrigerant conduit 15 is embedded in the stator base 2. Thereby, the effective thrust performance of a linear actuator can be improved and a temperature rise can be prevented.
Therefore, the stator base is composed of a non-magnetic member, and the yoke formed by laminating a thin silicon steel plate is disposed between the armature portion and the stator base, so that the magnet can be compared with a solid magnetic member. Since the eddy current generated when the motor is driven can be reduced, the yoke part iron loss can be greatly reduced.
Further, since the refrigerant conduit 15 is embedded in the stator base 2, the armature positioned in the vicinity of the stator base 2 is efficiently cooled, so that the temperature rise of the armature portion is reduced, and the linear actuator Can improve the cooling performance.
In the present embodiment, the configuration using the forced liquid cooling refrigerant conduit 15 is described, but a forced liquid cooling jacket may be used instead.

Next, a third embodiment of the present invention will be described.
FIG. 3 is a moving magnet type linear actuator showing a third embodiment of the present invention, in which (a) is a plan view thereof, and (b) is a front sectional view taken along line BB of (a). Yes, (a) corresponds to the view seen through from arrow A in (b).
In FIG. 3, 13 is a cover.
The third embodiment is different from the first and second embodiments as follows.
That is, a cover 13 that covers the side surface is attached to the side surface of the linear actuator, and the cover 13 is subjected to a punching process that matches the shape of the sensor 6 so that the sensor 6 does not interfere on the side where the linear scale 8 is attached. It is the point which gave.
In addition, a resin 16 or a ceramic member is sandwiched as a heat insulating material between the both end attachment portions of the linear guide and the attachment portion of the stator base 2 provided with the armature portion.
Therefore, since the cover 13 that covers the side surface of the linear actuator is attached, even if a magnetic material or foreign matter falls on the linear actuator from the outside, the gap between the mover and the stator or the magnetic material or foreign matter between the linear guides Mixing can be prevented, and good measures can be taken to improve the accuracy of the linear actuator and the life of the linear guide.
Moreover, since the resin 16 is provided between the both ends of the linear guide and the mounting portion of the stator base 2 provided with the armature portion, heat transfer to the movable body is hindered, and accuracy change due to thermal expansion is suppressed. can do.

1 is a moving magnet type linear actuator showing a first embodiment of the present invention, wherein (a) is a plan view thereof, (b) is a front sectional view taken along line BB of (a), ) Corresponds to a view seen through from arrow A in (b). It is a moving magnet type linear actuator which shows 2nd Example of this invention, Comprising: (a) is the top view, (b) is a front sectional view which follows the BB line of (a), (a ) Corresponds to a view seen through from arrow A in (b). It is a moving magnet type linear actuator which shows the 3rd example of the present invention, (a) is the top view, (b) is the front sectional view which meets the BB line of (a), (a ) Corresponds to a view seen through from arrow A in (b). 1 is a moving magnet type linear actuator showing a prior art, in which (a) is a plan view thereof, (b) is a front sectional view taken along line BB of (a), and (a) is (b). This corresponds to a view seen through from the arrow A in FIG.

Explanation of symbols

1: Armature 2: Stator base 2A: Sensor holder 3: Field permanent magnet 4: Field yoke 5: Linear guide rail 6: Sensor (linear scale detector)
7: Linear guide block 8: Linear scale portion 9: Stopper 10: Sensor lead 11: Motor lead 12: Armature yoke 13: Cover 14: Movable table 15: Refrigerant conduit 16: Resin (thermal insulating material)

Claims (5)

In the moving magnet type linear actuator in which the armature portion is arranged on the stator side and the field magnet portion is arranged on the mover side, and the position of the mover in the sliding direction with respect to the stator is detected by an encoder.
The stator is arranged in a straight line so as to face the armature portion, a stator base, an armature portion fixed to the stator base and mounted with a plurality of coil groups, and a U-shaped cross section. A linear guide rail having
The movable element is disposed in a concave portion of the linear guide rail, and is fixed to an upper portion of the linear guide block, and a linear guide block that slides on both inner side surfaces of the linear guide rail via rolling elements. A movable table arranged so as to straddle the linear guide rail, and a permanent field provided on the upper portion of the movable table via a field yoke and opposed to the armature portion via a magnetic gap. A field portion made of a magnet,
The encoder includes an optical linear scale disposed on a side surface of the movable table, and a sensor that faces the linear scale and is disposed on the stator base side and detects the linear scale. A moving magnet type linear actuator characterized by being an optical encoder. 2. A motor according to claim 1, wherein said stator base is made of a non-magnetic member, and a yoke formed by laminating a thin silicon steel plate is disposed between said armature portion and said stator base. Bing magnet type linear actuator. 3. The moving magnet type linear actuator according to claim 1, wherein a refrigerant conduit or a forced liquid cooling jacket is embedded in the stator base. A cover that covers a side surface of the linear actuator is attached, and the cover is subjected to a punching process in accordance with the shape of the sensor so that the sensor does not interfere with the side on which the linear scale is attached. The moving magnet type linear actuator according to claim 1 or 2. 3. A resin or a ceramic member is sandwiched as a heat insulating material between both ends of the linear guide and a stator base mounted with the armature portion. The moving magnet type linear actuator described.

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