JPH0654515A - Linear dc motor with built-in linear magnetic encoder - Google Patents

Abstract

PURPOSE:To get a thin and accurate linear DC motor with a built-in linear magnetic encoder suitable for load and momental load in any direction by forming a limitless circulation path for a roller in a slider guide, and also, attaching a scale for a linear magnetic encoder, in parallel with the recess of a direct action guide rail. CONSTITUTION:Truck grooves 15 for load opposed to the truck grooves 7 for load made in a direction action guide rail 3 and extending longitudinally in the shifting direction of a slider 2 are made at the inner faces on both sides of a slide unit 24. And, groups of rollers 16 are interposed between the truck grooves 7 and 15, thus this device is constituted so that the slider 2 can shift smoothly. What is more, a return passage 25 for the roller 16 is made and it is made a limitless circulation path. Moreover, a scale 12 for a linear magnetic encoder is attached to the direct action guide rail 3, and a magnetic sensor 18 is attached to the slide unit 24 through magnetic space, whereby the quantity of shifting of the slider 2, the speed of shifting, and the shifting position are detected to control the speed and the position of the slider 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is suitable for loads in all directions of up, down, left and right, and for moment loads, even if the load is large and large thrust is required, and the stroke length is long. The present invention relates to a linear DC motor linear with a built-in linear magnetic encoder of high accuracy which is thin and highly accurate even if the linear magnetic encoder is built in the linear motion guide unit.

[0002]

2. Description of the Related Art In a linear DC motor, particularly a multi-pole / multi-coil type multi-phase linear DC motor, the magnetic poles of N pole and S pole are set to P (P) so that adjacent magnetic poles have different polarities. Is an integer of 2 or more)
A field magnet is provided with each of them to form a field magnet, and n (n is 2
(The above integer) armature coils are arranged to form an armature, and either the field magnet or the armature is attached to a slider that moves relatively, and the other is a stator. There is.

For example, in a multi-pole multi-phase linear DC brushless motor, the magnetic pole of the field magnet is discriminated by a magnetic pole discriminating element to switch the energization of the armature coil in an appropriate direction to linearly move the slider. ing. In a linear DC brushless motor that makes such a straight running, it is desirable to carry out a closed loop control using a linear encoder in order to perform the speed control and the positioning control with high accuracy.

Here, in the case of forming a compact and highly accurate linear DC motor with a built-in linear encoder by rationally incorporating the components of the linear encoder into the linear DC brushless motor, the linear encoder is Simple structure,
It is a good idea to use a linear magnetic encoder that is compact and can be constructed at low cost, but a linear magnetic encoder must be installed in a linear DC motor that satisfies the various conditions described below and has a linear motion guide unit. There is no linear DC motor that can be built in compactly.

In the conventional linear DC brushless motor using the linear magnetic encoder, the scale material for the linear magnetic encoder is previously provided with N poles and S poles at equal intervals along the longitudinal direction of the slider. The magnetic poles of the poles are finely magnetized to form a scale for the linear magnetic encoder, and the scale for the linear magnetic encoder is attached to an appropriate fixed portion of the device or the linear DC brushless motor, and the slider is attached. A magnetic sensor that moves together detects the fine magnetic poles of N pole and S pole of the scale for the linear magnetic encoder.

[0006]

As a linear DC motor using a linear motion guide unit, there is one using a cross roller as disclosed in Japanese Utility Model Laid-Open No. 57-118677. According to the linear motor using the linear motion guide unit of the cross roller built-in type, it is not possible to form a linear DC linear motor which requires a long stroke length, and the linear motion guide unit also has a large thickness. It becomes a large one,
Stroke with a compact built-in linear magnetic encoder
There is a drawback that it is not possible to form a thin linear DC motor having a long length.

There is also a method of using a linear motion guide unit which rolls a track roller bearing having a groove on a rail and runs a slider as shown in Japanese Patent Publication No. 63-27946. However, it is not possible to obtain a linear DC motor with excellent running accuracy, and it is not possible to support an upward load. Further, there are various drawbacks such that a long life linear DC motor having a large load capacity and a large thrust cannot be constructed.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to suit the load in all directions of up, down, left and right, and the moment load even if the load capacity is large and large thrust is required, and the stroke length is long. It is suitable for long lengths, and even if a linear magnetic encoder is built in the linear motion guide unit, it is possible to form a thin, highly accurate linear DC motor with a built-in linear magnetic encoder. Especially.

[0009]

SUMMARY OF THE INVENTION In order to accommodate the armature or the field magnet along the moving direction of the slider, the cross section perpendicular to the moving direction of the slider is substantially concave. A track groove extending along the longitudinal direction of the linear motion guide rail is formed on both outer side walls of the linear motion guide rail, and the slider is moved into the recess of the linear motion guide rail. N (along an integer greater than or equal to 2) P magnetic poles (P is an integer of 2 or more) such that adjacent magnetic poles adjacent to each other have different polarities are formed along the moving direction of the field magnet or the slider. n is an integer greater than or equal to 2) The armature composed of armature coils is housed and arranged, and the linear motion of the slider has an inner raceway groove extending in the longitudinal direction facing the raceway groove of the linear motion guide rail. Field magnet or electric machine provided in the recess of the guide rail An armature or a field magnet is provided on the surface opposite to the linear motion guide rail and the slider so as to relatively move, and a raceway groove formed on the outer side wall of the linear motion guide rail. A rolling element return path communicating with the raceway groove forming the load path is formed in a slider having opposed raceway grooves extending in the longitudinal direction on the inner surface to form an endless circulation path of the rolling element, A rolling element is rotatably accommodated in the infinite circulation passage, a linear magnetic encoder scale is attached in parallel with the concave portion of the linear guide rail, and the linear magnetic encoder scale is provided. Achieved by providing a linear DC motor with a built-in linear magnetic encoder equipped with magnetic sensors for detecting the N pole and S pole of the scale for the linear magnetic encoder at opposing slider positions. it can.

[0010]

1 is a perspective view of a multi-pole multi-phase type movable magnet type linear DC brushless motor 1 incorporating a linear magnetic encoder, with a part of which is omitted.
1 is a vertical cross-sectional view of the same multi-pole, multi-phase type movable magnet type linear DC brushless motor 1 as seen from the traveling direction of the slider, which is indicated by the XY line. The magnet type linear DC brushless motor 1 will be described.

A movable magnet type linear DC brushless motor 1 mainly comprises a slider 2 which constitutes a moving element, and a linear motion guide rail 3 which constitutes a stator.

The linear guide rail 3 has a recess 5 for accommodating an armature in which a cross section orthogonal to the moving direction of the slider 2 is a substantially recess for accommodating the armature 4 along the moving direction of the slider 2. Is formed.

An insulating sheet 2 is provided on the upper surface of the armature housing recess 5.
2, the armature coil 8 and the linear motion guide rail 3 which will be described later are provided.
And electrical insulation processing is performed. In this case, when the linear motion guide rail 3 is not made of a magnetic material, the insulating sheet 22 may be provided after the magnetic material plate is interposed.

On both rail side surfaces 6 of the linear guide rail 3, a track groove 7 for loading is formed extending along the longitudinal direction of the linear guide rail 3.

On the upper surface of the armature accommodating recess 5 of the linear guide rail 3, a plurality of air-core type armature coils 8 are arranged so as not to overlap each other along the moving direction of the slider 2. The coreless stator armature 4 having a coreless structure is housed and arranged.

Explaining the armature coil 8, the armature coil 8 is formed by winding a large number of turns using a conductive wire so as to be an air-core type having a rectangular frame shape. Alternatively, a sheet coil or the like using a plating means or an etching means may be used. Further, in this embodiment, a large number of armature coils 8 are arranged adjacent to each other so as not to overlap each other, but the armature coils 8 are not necessarily arranged closely adjacent to each other. It doesn't have to be.

According to the air-core type armature coil group 8 as described above, the thrust force extending in the direction orthogonal to the traveling direction of the slider 2 can be adopted so that the linear reciprocating 180-degree energization method having good efficiency and performance can be adopted. The open angle between the two effective conductor portions 8a and 8a that contributes to the generation is the open angle of the one magnetic pole width T, where T is the one magnetic pole width of the field magnet 9 in the traveling direction of the slider 2 described later. The winding is formed so that

In the armature coil 8, the slider 2
The two conductor portions 8b parallel to the moving direction of are conductor portions that do not contribute much to the generation of thrust. Further, the armature coil 8 has two conductor portions 8b that do not contribute to the generation of the above thrust.
The length of the conductor 8b to the outside is the same as the width of the field magnet 9 in that direction.

The upper surface of each armature coil group 8 forming the coreless stator armature 4 has a longitudinal width substantially equal to that of the armature coil 8 and prevents dust and the like from entering. In order to protect the armature 4, a long plate-shaped printed wiring board 10 having a slightly larger lateral width is arranged and fixed by a screw 23. Reference numeral 20 indicates a color.
A printed wiring conductive pattern (not shown) is formed on the printed wiring board 10. Via this pattern, the armature coils 8 and the field magnets 9 are arranged according to the magnetic pole states of the armature coils 8 and the field magnets 9. Power is supplied to the magnetic pole discriminating element 21 such as a hall element for position detection for switching energization, and an output signal is obtained.

The magnetic pole discriminating element 21 is a hole I.
An appropriate magnetoelectric conversion element such as C, a hall element, or a magnetoresistive element may be used. The magnetic pole discriminating element 21 group is on a conductor extension line where a conductor portion 8a that contributes to the thrust generated by the armature coil 8 and a conductor portion 8b that is orthogonal to the conductor portion 8a and does not contribute to the thrust generation intersect. Field magnet 9
The magnetic poles of the N pole and the S pole of the field magnet 9 can be detected by arranging them on the lower surface of the printed wiring board 10 facing the Based on an output signal from the magnetic pole discriminating element 21 corresponding to the magnetic poles of the N pole and the S pole of the field magnet 9, a driver in an energization control circuit (not shown) is activated to generate thrust in a predetermined direction. The armature coils 8 are energized in an appropriate direction.

A linear magnetic encoder scale 1 is provided on the linear motion guide rail 3 in parallel with the armature accommodating recess 5.
A linear magnetic encoder scale accommodating groove 13 for accommodating 2 is formed, and a linear magnetic encoder scale 12 is adhered to the linear magnetic encoder scale accommodating groove 13 Is attached and formed.

The slider 2 is made of an appropriate material, and has a lower surface for closing the magnetic path of a field magnet 9 formed in an inverted concave shape when viewed from the running direction of the slider 2. A magnet yoke 11 made of a magnetic material is fixed, and L-shaped slide units 24 are attached to both sides of the magnet yoke 11 with screws 19 or the like.

On both inner surfaces of the slide unit 24, a load track which faces the load track groove 7 formed in the linear motion guide rail 3 and extends in the longitudinal direction along the moving direction of the slider 2. A groove 15 is formed, and a group of rolling elements (guide balls) 16 is interposed between the raceway grooves 7 and 15, and the slider is provided along the longitudinal direction of the raceway groove 7 by the raceway grooves 7 and 15 and the group of rolling elements 16. 2 is configured to be able to move smoothly.

The slide unit 24 has a raceway groove 15
A rolling passage 25 is formed inside the outer position of the rolling passage 16 so as to communicate with the raceway grooves 7 and 15 and permit the direction change and the reciprocal rolling of the rolling body 16 by the end gap. To form an infinite circulation passage.

The magnet yoke 11 is constructed so that the air gap length (magnetic air gap length) between the linear motion guide rail 3 and the surface of the armature housing recess 5 is parallel. It has a planar lower inner surface 17 opposed to the lower inner surface 17 and is provided with a field magnet 9 on the surface of the lower inner surface 17 facing the armature 4 for relative movement.

On the lower inner surface 17 of the magnet yoke 11, N and S magnetic poles are provided as P (P is 2 or more) so that adjacent magnetic poles have different polarities in the moving direction of the slider 2. In this embodiment, the field magnet 9 having three poles is fixed by using an appropriate means such as an adhesive for convenience of drawing.

In the portion of the upper inner surface 26 of the slide unit 24 facing the linear magnetic encoder scale 12, the linear magnetic encoder scale 12 is alternately formed at a fine pitch. A magnetic sensor 18 for detecting the magnetic poles of the N pole and the S pole is attached through a parallel magnetic gap, and the N pole of the scale 12 for the linear magnetic encoder is
The S-pole magnetic pole fine multi-pole attached magnetic pole can be detected. As a result, the magnetic sensor 18 counts the number of N-pole and S-pole fine multi-pole magnetic poles of the magnetic pole of the linear magnetic encoder scale 12, whereby the moving amount, moving speed, moving position, etc. of the slider 2 are determined. , By this, the speed of the slider 2,
Position servo can be performed.

[0028]

When the armature coil group 8 is energized in the appropriate direction in accordance with the signal from the magnetic pole discriminating element 21 and thrust is generated, the rolling elements 16 roll in the infinite circulation passage due to loads in all directions. Therefore, the slider 2 smoothly moves in a predetermined direction.

[0029]

As described above, the present invention provides a linear motion guide unit having an infinite circulation passage which can smoothly drive the slider even when a load or a moment load is applied in all directions.
Even if the load is large and a large thrust is required, the stroke length is long, and even if the linear magnetic encoder is built in the linear motion guide unit, the thickness is thin and high. It is possible to form a linear DC motor with a built-in linear magnetic encoder with high accuracy and long life. In the above embodiment, the movable magnet type linear brushless motor has been described, but it is also applicable to the movable armature type linear brushless motor in which the field magnet is fixed and the armature is the mover. It goes without saying that the present invention is also applicable to a DC linear motor that uses a brush and a commutator instead of the brushless type.

[Brief description of drawings]

FIG. 1 is a top perspective view of a multipole / multiphase movable magnet type linear DC brushless motor 1 in which a linear magnetic encoder is incorporated, with some cutouts omitted.

FIG. 2 is a vertical cross-sectional view of the same multi-pole multi-phase type movable magnet type linear DC brushless motor as seen from the traveling direction of the slider, which is indicated by an XY vertical cross-section line.

[Explanation of symbols]

 1 movable magnet type linear DC brushless motor 2 slider 3 linear motion guide rail 4 armature 5 armature housing recess 6 rail side surface 7 (for load) raceway groove 8 armature coil 8a For generating thrust Conductor part 8b that contributes Conductor part that does not contribute to generation of thrust 9 Field magnet 10 Printed wiring board 11 Magnet yoke 12 Scale for linear magnetic encoder 13 Scale storage groove for linear magnetic encoder 15 ( (For load) Raceway groove 16 Rolling element 17 Upper inner surface 18 Magnetic sensor 19 Screw 20 Color 21 Magnetic pole discriminating element 22 Insulation seal 23 Screw 24 Slide unit 25 Return path 26 Upper inner surface

Claims (1)

[Claims] 1. A linear DC motor with a built-in linear magnetic encoder comprising the following components. The linear motion guide rails are formed on both outer side walls of the linear motion guide rails whose cross section orthogonal to the moving direction of the slider is substantially recessed for accommodating an armature or a field magnet along the moving direction of the slider. The track groove is formed so as to extend along the longitudinal direction of the groove. P magnetic poles of N and S poles (P is an integer of 2 or more) are formed in the concave portion of the linear motion guide rail so that adjacent magnetic poles are different poles along the moving direction of the slider. The armature consisting of n (n is an integer of 2 or more) armature coils is housed and arranged along the moving direction of the field magnet or the slider. A slider having a raceway groove extending in the longitudinal direction facing the raceway groove of the linear motion guide rail on the inner surface is provided on the surface facing the field magnet or armature provided in the recess of the linear motion guide rail. A child or a field magnet is provided so that the linear motion guide rail and the slider can be moved relative to each other. A rolling element return path communicating with the raceway groove forming the load passage is formed in the slider having an inner surface having a raceway groove extending in the longitudinal direction facing the raceway groove formed on the outer side wall of the linear motion guide rail. To form an endless circulation path for the rolling elements. The rolling element is rotatably accommodated in the infinite circulation passage of the rolling element. The scale for the linear magnetic encoder should be attached parallel to the recess of the linear motion guide rail. At the slider position facing the scale for the linear magnetic encoder, N of the scale for the linear magnetic encoder is provided.
A magnetic sensor for detecting the magnetic poles of the pole and the S pole is attached.