JP3268101B2 - Positioning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a positioning device for moving various materials to predetermined positions in a wide range of fields such as robots, machine tools, semiconductor devices, etc. The present invention relates to a positioning device having a table, in which a linear motor having a special configuration is effectively arranged, thereby enabling downsizing and flattening, as well as high-speed and high-precision positioning.

[0002]

2. Description of the Related Art As a positioning device having a moving table movably arranged in one axis direction, as shown in FIG. 6, a moving table 3 is moved by a predetermined amount via a ball screw 2 connected to a stepping motor 1 as shown in FIG. A known configuration is known. 4 is a bed in the figure. That is, the moving table 3 is moved in a predetermined uniaxial direction by converting the rotational movement of the stepping motor 1 into a linear movement by the ball screw 2.

FIG. 7 shows a configuration of another positioning device, which is configured to use a voice coil type linear motor (hereinafter referred to as VCM) 10 as a driving source of a moving table. The VCM 10 includes a magnetic circuit section 11 and a movable coil 12, and the movable coil 12 is integrally connected to a moving table 13 which is arranged on a bed 14 by a predetermined means so as to be movable in one axis direction. That is, the moving table 13 is moved in a predetermined uniaxial direction by directly transmitting the linear motion of the movable coil 12 constituting the VCM 10 to the moving table 13.

[0004]

In recent years, in these positioning devices, not only miniaturization but also flattening according to the application has been strongly desired, and there has been a high demand for improvement of responsiveness. It is desired to realize high-speed and high-accuracy positioning. In the positioning device using the stepping motor 1 shown in FIG.
In order to move the moving table 3 at high speed, it is necessary to increase the acceleration of the moving table 3. The acceleration is determined by the ratio (m / F) between the inertial mass (m) of the moving table 3 and the torque (F) of the stepping motor 1, and the inertial mass (m) of the moving table 3 is reduced as much as possible. It is required that the torque (F) be as large as possible.

However, the stepping motor 1 and the moving table 3 are arranged in series via the ball screw 2. To convert the rotational movement of the stepping motor 1 into a linear movement, the connection between the ball screw 2 and the moving table 3 must be established. Since it is indispensable, the reduction of the inertial mass of the moving table 3 is limited. Also, the torque of the stepping motor 1 is usually
It is proportional to about the square of the diameter of the motor and about the square of the length.
Therefore, reducing the diameter of the stepping motor 1 for the purpose of flattening the motor 1 itself results in a large decrease in torque. On the other hand, if the aim is to increase the torque by increasing the length, the projecting portion of the motor 1 becomes very large, and it is not possible to achieve the miniaturization of the entire positioning device. As described above, in the positioning apparatus using the stepping motor 1 shown in FIG. 6, it has been difficult to satisfy both miniaturization, flattening and high speed.

In the above-described positioning apparatus using the VCM 10 shown in FIG. 7, since the movable coil 12 and the moving table 13 constituting the VCM 10 are directly connected, the moving table is compared with the positioning apparatus shown in FIG. 13 is relatively easy to realize. But,
The torque of the VCM 10 depends on the magnetic flux density (B) in the magnetic field in which the movable coil 12 is disposed, the conductor length (L) of the conductor constituting the movable coil 12 located in the magnetic field, and the movable coil 12. Product (B × L)
XA). In order to realize an increase in torque by improving the configuration of the magnetic circuit without increasing the overall height of the VCM 10, it is necessary to increase the length of the movable coil 12 in the moving direction. Is required. Accordingly, as the length of the movable coil 12 increases, the length of the magnetic circuit section inevitably increases, and the magnetic circuit section is formed in order to form a smooth magnetic path without saturating the magnetic flux generated from the permanent magnet. It is necessary to increase the thickness of each yoke, and as a result, the height of the VCM 10 is increased.

The present invention solves the drawbacks of the conventional positioning device as described above, and in particular, enables the miniaturization and flattening by effectively disposing a linear motor having a special configuration. It is an object of the present invention to propose a positioning device capable of high-speed and high-accuracy positioning.

[0008]

According to the present invention, a yoke shape of a magnetic circuit portion constituting a linear motor serving as a driving source of a moving table and an arrangement of permanent magnets and a movable coil are devised. The entire lower surface of the moving table is a linear motor unit, and in particular, a bearing that supports the magnetic circuit unit and the moving table relatively movably at a predetermined position such as a yoke constituting the linear motor is movable. The large thrust generated in the coil can be directly applied to the moving table efficiently, thereby achieving the above object.

That is, the present invention relates to a positioning apparatus having a moving table movably disposed in one axis direction , wherein the moving table driving linear actuator is provided below the moving table.
A linear motor is connected to a pair of plate-like yokes that are opposed to each other by forming a predetermined gap at a central yoke and are integrated with the moving direction of the moving table.
A magnetic path forming yoke having a substantially D-shaped cross-section in the cross direction;
Symmetric position via the central yoke, and at least one of the opposing surfaces of the pair of plate-like yoke, the magnetic having a pair of plate-shaped permanent magnet to secure the different magnetic poles disposed adjacent each moving direction of the moving table and the circuit portion, the shape in the pair of plate-like yoke held integrally connected to the moving table
And a pair of flat movable coils disposed opposite to the plate-shaped permanent magnets in the gaps formed, and
A magnetic table and a moving table, which constitute a motor, are relatively movably arranged.

[0010]

The positioning apparatus according to the present invention will be described in detail with reference to an embodiment shown in FIGS. FIG. 1 is an explanatory view of a longitudinal section, and FIG. 2 is an explanatory view of an aa transverse section of FIG. In the positioning device 20 of the present invention, substantially the entire lower surface of the moving table 30 is used as a linear motor unit, and the linear motor is composed of a magnetic circuit unit 21 and a movable coil 27 that is arranged integrally with the moving table 30. Further, a bearing 32 is provided at a predetermined position of a yoke constituting the magnetic circuit portion 21 so that the magnetic circuit portion 21 and the moving table 30 are relatively movably arranged.

The magnetic circuit section 21 will be described in detail. First, the yoke for forming a magnetic path is formed such that a pair of flat yokes 22, 23 are opposed to each other with a predetermined gap 24 formed therebetween. Central yoke 25 located in the central part of
Is connected and integrated in a substantially D-shape. The yoke in the present invention is Ryakue type yoke cross section of the main part of the magnetic path forming represents Oh Rukoto in Ryakue type, and means for the bearing arrangement to be described below, various other members The overall yoke cross-sectional shape does not need to be substantially D-shaped due to means added for disposition. In addition, a pair of flat yokes 22, 23
The central yoke 25 and the central yoke 25 may be assembled independently of each other.
It is desirable to appropriately select one of them, taking into account the shape and dimensions of the yoke, assembling workability, workability, etc., such as forming one of the central parts 2 and 23 and the central yoke 25 as an integral product.

A flat movable coil 27, which will be described later, is disposed in the space 24. A permanent magnet is used as a magnetic field generating means for applying a propulsive force to the flat movable coil 27. It is necessary to arrange them at predetermined positions. In the present invention, the central yoke 25
And a pair of flat yokes 22 and 2
3 is provided on at least one of the opposing surfaces,
(In the figure, the direction of the arrow: the direction of movement of the moving table 30 and the direction of movement of the movable coil 27 are the same, so the direction of movement is shown in the figure for the flat movable coil 27).
A pair of plate-shaped permanent magnets having different magnetic poles adjacent to each other are fixed thereto. In the figure, a pair of plate-like permanent magnets 26, 2 are symmetrically placed on a lower yoke 22 of the pair of plate-like yokes 22, 23 via a central yoke 25, respectively.
6 is fixed. The pair of flat permanent magnets 26, 26 are magnetized in the thickness direction, and have different magnetic poles adjacent to each other in the moving direction of the moving table 30.
26d. These 26a, 26b (2
6c and 26d) can also be obtained by magnetizing an integral flat permanent magnet such that different magnetic poles are adjacent to each other. However, 26a and 26b (26c and 26d) may be constituted by independent magnets.

Further, in the drawing, the description has been made of the configuration in which the pair of plate-shaped permanent magnets 26, 26 are arranged on the yoke 22 located on the lower side. However, the configuration is arranged on the yoke 23 located on the upper side. One side is disposed on the yoke 22 located on the lower side, and the other side is disposed on the yoke 23 located on the upper side. A structure in which substantially the same magnetic field strength acts on the flat movable coils 27, 27 located in the gaps 24, 24 formed in
In other words, it is sufficient that the permanent magnets are arranged at symmetrical positions via the central yoke 25, and it is desirable to appropriately select their arrangement in consideration of the magnetic properties of the permanent magnets, the workability of assembly, and the like. Various known materials can also be used for the material of the flat permanent magnet. In particular, in the present invention for the purpose of miniaturization and flattening, a neodymium-based rare-earth magnet having excellent magnetic properties, for example, having a maximum energy product of 30 MGOe or more is used. Is preferred.

In the magnetic circuit section 21 having the above-described yoke configuration and magnet arrangement, for example, a magnetic path formed by the flat permanent magnet 26b in the drawing will be described. A magnetic path consisting of the magnet 26b → the lower yoke 22 → the center yoke 25 → the upper yoke 23 → the plate-shaped permanent magnet 26b is formed to form a magnetic field having a predetermined strength in the gap 24. The magnetic path formed by the plate-shaped permanent magnet 26d is as shown by a broken line B in the figure. The magnetic path formed by the plate-shaped permanent magnet 26a is a magnetic path in the direction opposite to the broken line A in the figure, and the magnetic path formed by the plate-shaped permanent magnet 26c is a magnetic path in the direction opposite to the broken line B in the figure. .

A gap 24 formed in the magnetic circuit portion 21
Inside, a pair of flat movable coils 27, 27 are arranged to face the plate-shaped permanent magnets 26, 26, respectively. More specifically, in order to make the action of the magnetic field on the flat movable coils 27 and 27 uniform (ie, to make the torque constant) when the flat movable coils 27 and 27 move, it is necessary to use the illustrated components. As described above, only the portions (short portions in FIG. 2) corresponding to the direction perpendicular to the moving direction in each of the flat movable coils 27, 27 have different magnetic pole portions (26a and 26b and 26c and 26d) of the plate-like permanent magnets 26, 26. ) Is desirably located immediately above the parentheses. The above-mentioned flat movable coils 27, 27 are respectively provided with coil holders 28,
Although it is held at 28, it is further integrally connected to the moving table 30 by connecting members 29 and 29. That is, the linear movement of the flat movable coils 27, 27 is the linear movement of the moving table 30 directly.

The moving table 3 integrated with the magnetic circuit section 21 and the flat movable coils 27, 27 described above.
0 means that the well-known bearing means is disposed between at least one of the pair of plate-like yokes 22 and 23 constituting the magnetic circuit portion 21 and the moving table 30, for example, so that the bearing means relatively moves through the bearing. Arranged freely. In the figure, a configuration is shown in which bearings 32 are arranged between bearing support portions 31, 31 erected at both end portions of a flat yoke 22 located at a lower portion and both end portions of a movable table 30. In the configuration described above, the flat movable coils 27, 27
When a current in a predetermined direction is applied to the flat movable coils 27, 27, and a movable table 30 integrally connected to the flat movable coils 27, 27 together with the flat movable coils 27, 27 due to the interaction with the magnetic field in the air gap 24, in a predetermined uniaxial direction Go to

FIGS. 3, 4 and 5 are partial longitudinal sectional views showing another embodiment of the present invention. In any of the configurations, the configuration of the magnetic circuit section 21 is basically the same, and the arrangement configuration of the bearing 32 for relatively movably disposing the moving table 30 and the magnetic circuit section 21 is different. FIG.
The bearing 32 is arranged between the plate-like yoke 23 located at the upper part of the magnetic circuit portion 21 and the moving table 30. In the drawing, the outer peripheral surface of the side end of the plate-like yoke 23 and the moving table 30 The bearing 32 is arranged between the inner peripheral surface of the side end and the flat permanent magnet 26 is also fixed to the inner surface of the flat yoke 23 located above.

FIG. 4 shows a structure in which a bearing 32 is disposed between a flat plate yoke 22 located at the lower part of the magnetic circuit section 21 and the moving table 30. In FIG. A bearing 32 is disposed between the outer peripheral surface and the inner peripheral surface at the side end of the moving table 30, and the flat movable coil 27 moves directly via the coil holder 28 without using the connecting member 29 in FIG. It is connected integrally with the table 30. FIG. 5 shows a non-magnetic material (for example, Al or an Al alloy or the like) on which the magnetic circuit portion 21 is fixedly arranged.
A bearing 32 is arranged between a base member 33 made of a material and the moving table 30. In the figure, an inner peripheral surface of a bearing support portion 34 erected at a side end of the base member 33 and a side of the moving table 30 are shown. The bearing 32 is arranged between the outer peripheral surface and the end. In any of the configurations, the same effects as those of the positioning device having the structure shown in FIGS. 1 and 2 can be obtained, and in the configurations other than those shown in the drawings, the movement of the moving table 30 in the one axial direction is smoothly realized. It is desirable to select an appropriate configuration in consideration of the mounting of the bearings, the working of the flat yokes 22, 23, and the like.

[0019]

[Embodiment] The maximum energy product is 36MGOe in the permanent magnet which is the source of the magnetic field of the motor that applies thrust to the moving table.
Using a neodymium-based rare-earth magnet consisting of, the positioning device of the present invention shown in FIG. 1 and the conventional positioning device shown in FIG. 6 and FIG. The maximum speed was measured. In addition, the above measurement was performed in a configuration where the resolution was set to 1 μm, the height of each motor was set to 40 mm, and the stroke of the moving table was set to ± 20 mm by arranging a predetermined position sensor and the like in each positioning device. Was carried out.

The maximum speed of the moving table in the positioning device shown in FIG. 6 was about 20 mm / sec, and the maximum speed of the moving table in the positioning device shown in FIG. 7 was about 200 mm / sec. Compared with these conventional positioning devices, it has been confirmed that the positioning device according to the present invention shown in FIG. 1 has a maximum speed of the moving table of 450 mm / sec or more, which enables very high-speed response. Therefore, if the same characteristics as those of the related art are obtained, further flattening is possible. For example, even if the motor height is 30 mm, the maximum speed of the moving table in the positioning apparatus shown in FIG. The maximum speed (about 420 mm / sec) is obtained, and the flattening can be performed to a thickness of about 1/2 of the conventional thickness.

[0021]

According to the present invention, as is apparent from the above embodiments, the shape of the yoke of the magnetic circuit and the arrangement of the permanent magnets and the movable coils constituting the linear motor serving as the driving source of the moving table are devised. Thus, substantially the entire lower surface of the moving table is formed as a linear motor portion, and the thrust is increased by increasing the substantial conductor length of the movable coil located in the magnetic field without increasing the magnetic circuit portion. By realizing and arranging a bearing part that movably supports the moving table at a predetermined position such as a yoke that constitutes a linear motor, thrust can be efficiently applied to the moving table directly connected to the moving coil. In addition, since the inertial mass of the moving table itself can be reduced, the size and flatness required of the positioning device have recently been increased, One highly accurate positioning can allow the.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing an embodiment of a positioning device according to the present invention, which is a sectional view in a direction orthogonal to a moving direction of a moving table .
Surface.

FIG. 2 is an explanatory sectional view showing one embodiment of the positioning device of the present invention, and is an explanatory sectional view taken along the line aa in FIG. 1;

FIG. 3 is an explanatory partial sectional view showing another embodiment of the positioning device of the present invention.

FIG. 4 is a partial sectional explanatory view showing another embodiment of the positioning device of the present invention.

FIG. 5 is a partially sectional explanatory view showing another embodiment of the positioning device of the present invention.

FIG. 6 is an explanatory perspective view showing a conventional positioning device using a stepping motor.

FIG. 7 is a perspective explanatory view showing a conventional positioning device using a voice coil type linear motor.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H02K 33/18 B23Q 5/28 G05D 3/00 H01L 21/68

Claims (1)

(57) [Claims] 1. A positioning device having a moving table movably arranged in one axial direction, wherein the positioning table is
The moving table drive linear motor
The linear motor forms a predetermined gap and connects and integrates a pair of plate-like yokes facing each other at a central yoke, and has a cross-sectional shape substantially orthogonal to the moving direction of the moving table.
A magnetic path forming yoke, which is shaped like an e-shape , and different magnetic poles at symmetrical positions via the central yoke and at least one opposing surface of the pair of flat yoke in the moving direction of the moving table.
Each flat and <br/> magnetic circuit having a pair of flat plate-like permanent magnet fixed adjacent arranged in a space formed by being held integrally connected pair of plate-like yoke to the moving table A positioning device, comprising: a pair of flat movable coils arranged to face a cylindrical permanent magnet; and the magnetic circuit unit and a moving table constituting a linear motor are relatively movably arranged. .