JPS6110961A - Movable coil type linear dc motor - Google Patents

Abstract

PURPOSE:To enhance the machining accuracy and to simultaneously improve the productivity by separating a portion including a permanent magnet and an outer yoke added with a slider guiding mechanism, thereby enabling to independently machine them. CONSTITUTION:Permanent magnets 1 magnetized in the thicknesswise direction and ferromagnetic units 2 are alternately disposed to form a center yoke 3, and U-shaped outer yokes 4 are disposed at the prescribed interval on three sides of the yoke 3. Side yokes 5A, 5B for magnetically coupling are formed at both longitudinal ends of the yokes 4, 3. A movable coil 8 is formed in a rectangular section, and secured to a slider 8 guided and supported to an outer yoke 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention is a movable device suitable for driving parts of equipment that requires highly accurate positioning, such as assembly robots or X-Y stages incorporated in semiconductor manufacturing equipment. Regarding coil type linear DC motors.

[Background of the invention]

A conventional linear DC moke for positioning is disclosed in Japanese Patent Publication No. 58-49099, for example.
Permanent magnets magnetized in the thickness direction and arranged alternately so that the magnetization directions are different are provided on one side of the outer yoke,
A center yoke is placed with a certain gap from this permanent magnet, and both ends of the yokes are joined by side yokes to form a magnetic circuit, and the space between the outer yoke and the center yoke, which forms part of the magnetic circuit, is A movable coil is movably provided. A movable coil is coupled to a slider supported by a kite roller, and this guide roller rolls while being guided by a groove provided on the outside of the outer yoke. On the other hand, a permanent magnet is fixed to the inner side of the outer yoke. In this way, in conventional systems, members are attached using the inside and outside of the outer yoke, so in the case of a complete positioning device with high precision,
In one member, the guide surface must be processed with high precision and the permanent magnets must be aligned and bonded, which poses a problem in terms of productivity.

In addition, in the conventional magnetic circuit configuration, permanent magnets are simply arranged to face each other on both sides of the moving coil, and no permanent magnets are provided on the opposite side of the slider. Therefore, leakage magnetic flux occurs on the opposite side of the slider, and since this magnetic flux does not act at right angles to the moving coil, it does not contribute to the thrust force at all, and is wasted energy. By the way, in the case of trying to use the above-mentioned moving coil part, all the magnets must be placed outside the moving coil part, so the amount of permanent magnets increases as a whole, and it is cost-effective. . Furthermore, the magnetic flux does not act at right angles on the sliding side of the '6J moving coil, and it cannot contribute to the generation of thrust. As described above, the conventional moving coil type linear DC motor has the disadvantage that the magnetic flux generated by the permanent magnet cannot be effectively applied to the coil.

[Purpose of the invention]

The purpose of this invention is to provide a guide support mechanism for a moving coil and a permanent magnet. It is an object of the present invention to provide a moving coil type linear DC motor that can be manufactured with high precision and in which magnetic flux acts efficiently on a moving coil.

[Summary of the invention]

In the linear DC motor of this invention, multiple permanent magnets are made of ferromagnetic material in the direction of magnetization. A center yoke is formed by interposing the same poles to face each other at predetermined intervals, and a gap is formed between the center yoke and the outer yoke holding the permanent magnet, and within this gap, a magnet is placed along both yokes. According to the above structure, the outer yoke has a constant gear ratio with the center yoke, and the part facing the gap is made of a ferromagnetic material with a predetermined thickness. Since it is only necessary, the outer side of the outer yoke, that is, the guide surface of the slider can be processed with high precision. By arranging a twisted permanent magnet on the center line of the center yoke, most of the magnetic flux is directed to the outer yoke located outside of the center yoke, so there is no effect on the moving coil where the outer yoke surrounds the center yoke. The magnetic flux density acts and thrust is obtained.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described based on all the drawings. 1st
3 to 3 show a first embodiment of the present invention. A center yaw 3 is constructed by alternately arranging permanent magnets 1 and ferromagnetic 212 bodies 2 magnetized in the thickness direction. The center yoke 3 has a rectangular cross section, and has an integral structure in which each magnet has its magnetic pole facing the ferromagnetic material and the same poles facing each other and bonded to the ferromagnetic material. As shown in FIG. 2, U-shaped outer yokes 4 are arranged on three sides of the center yoke 3 at predetermined intervals of two. At both ends of the outer yoke 4 and the center yoke 3 in the longitudinal direction, side yokes 5A and 5B are added which are magnetically coupled, and a gap 6 is formed between the two members. This gap 6 forms a movement space for the movable coil 8 loosely fitted to the center yoke 3.

As shown in FIG. 2, the movable coil 8 has a rectangular cross section and is fixed to a slider 9 that is guided and supported by the outer yoke 6. (7) When driving a moving coil with a three-phase flow, wind three independent coils lla, llb, and 1ick around the coil bobbin JO as shown in Fig. 3, and connect each coil 1 between them. Three magnetic detection elements 12a, 12b, and J-2c such as Hall elements that detect magnetic flux are provided.

The slider 9 is attached to the outer surface of the U-shaped outer yoke 4 via a guide support mechanism 20 so as to straddle the upper open portion of the outer yoke.

This guide support mechanism 20 is composed of a guide support part 21 formed on the outer surface of the outer yoke along the longitudinal direction, and a traveling means 22 provided on the side of the slider that is supported by the guide support part and moves. There is. That is, in the first embodiment, a pair of V grooves are formed in the longitudinal direction on the outer surface of the outer yoke 4, sandwiching the center yoke 4, and a traveling means using a pole bearing is provided on the inner surface of the slider 9 facing the V grooves. The traveling means is fitted into a V-groove and is movably supported over the outer surface of the entire outer yoke of the slider.

Next, the operation of the first embodiment will be explained.

As shown in FIG. 4, the magnetic flux flows in a direction perpendicular to the gap and alternately reversed.

Therefore, the moving coil 8 in the gap is moved in a direction perpendicular to the direction of magnetic flux (longitudinal direction) by passing current.
The full thrust is generated. That is, the magnetic detection elements 12a, 12b
, 12c, the direction of the magnetic flux is detected based on the signal from the moving coil, and the other two coils except the one at the position where the direction of the magnetic flux changes are energized to generate full thrust, and the slider 9 fixed to the movable coil is The entire outer yoke 4 is overflowed and moved. The direction of this movement can be freely changed by changing the direction of the current flowing through each coil of the movable coil.

5 to 8 show other embodiments of the present invention,
Components that are the same as those in the first embodiment are given the same reference numbers and their explanations will be omitted.

5 and 6 show a second embodiment of the invention. In the second embodiment, all the constituent members have circular cross sections.

7 and 8 show a third embodiment of the invention. The third embodiment is the outer yoke 4 in the second embodiment.
The outer yoke has a diamond-shaped cross section, and the outer surface of the outer yoke is directly used as a static pressure guide surface 30 for the guide support mechanism of the slider 9, so there is no wobbling and the positioning accuracy of the slider can be improved. 32 is a static pressure pocket formed on the inner surface of the slider 9.

〔Effect of the invention〕

As described above, according to the present invention, the part containing the permanent magnet and the outer yoke part to which the slider's guide mechanism is fully attached are separated, so that they can be processed completely independently, so that processing accuracy cannot be improved. At the same time, productivity can be improved. In addition, since the center yoke is interposed in the direction of magnetization of the permanent magnet, the magnetic flux can be applied to the coil effectively.Compared to conventional magnets, the permanent magnet is smaller and has a smaller capacity to achieve the same thrust force. You can expect excellent effects such as good results.

[Brief explanation of the drawing]

FIG. 1 is a front view of a first embodiment of a moving coil type sunia flow mork according to the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 3 is a sectional view of the moving coil. FIG. 4 is a diagram showing the flow of magnetic flux in the magnetic circuit of the present invention, FIG. 5 is a front view of an embodiment of the body 2 of the present invention, FIG. 6 is a sectional view taken along line BB in FIG. 5, and FIG. 81 is a perspective view of the slider shown in FIG. 7. FIG. 81 is a perspective view of the third embodiment fli of the present invention. l... Permanent magnet, 2... Ferromagnetic material, 3... Center yoke, 4... Outer yaw, 5A, 5B... Zide yoke, 8... Moving coil, 9... Slider, 12a,
12b, 12c - magnetic detection element, 20... guide support mechanism.

Claims (4)

[Claims] (1) Two or more permanent magnets are provided so that they are magnetized in the thickness direction and the same poles face each other, and a ferromagnetic material is placed on both sides of the magnets in the direction of magnetization to form a center yoke. A ferromagnetic outer yoke is arranged with a gap of A moving coil type linear DC motor consists of a moving coil arranged so as to move along the moving coil. (2) The moving coil type linear DC motor according to claim 1, wherein the center yoke is formed to have a rectangular cross section, and the other sides except for this one side are surrounded by an outer yoke. (3) The movable structure according to claim 1, wherein the center yoke is formed to have a circular cross section, and an outer yoke having a circular cross section in which a slit is formed in the longitudinal direction is arranged with a certain gap between the center yoke and the center yoke. Coil type linear DC motor. (4) The center yoke is formed to have a circular cross section, and an outer yoke having a rhombic cross section with a slit formed in the longitudinal direction is arranged at a certain gap from the center yoke, and the outer surface of the outer yoke supports the movable coil. A moving coil type linear DC motor according to claim 1, wherein the moving coil type linear DC motor is used as a guide surface for a moving part.