JPH0521984Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is based on a movable element that faces a stator having an inductor protrusion, and a permanent magnet (PM) on the magnetic pole surface of the electromagnet.
Regarding PM type 4-phase Surf Ace motor with affixed.

[Conventional technology]

XY stage used in semiconductor manufacturing equipment,
OA equipment, peripheral equipment XY plotters, scanners,
Demand for Surf Eighth pulse motors is increasing for automatic drafting machines and other applications.

For example, Variable reluctance
A surface pulse motor manufactured by Xinetix, which has hybrid (HB) type linear pulse motors arranged on the X and Y axes, is in practical use.

One of them includes a device for controlling relative motion between two members along a single axis (Special Publication No. 49
-41602), which is a device consisting of a total of four variable magnetic resistance type three-phase linear pulse motors, two on the X axis and two on the Y axis. Two, a specific one
There is a device (Special Publication No. 52-7962) that controls the movement of an output member along two axes, and it consists of a total of four hybrid two-phase linear pulse motors, two on the X axis and two on the Y axis. It is a device. Furthermore, the prior art previously proposed by the applicant (Patent Application No. 122431/1986)
(Japanese Patent Application Laid-Open No. 62-89467) and the name of the invention is Surf Eighth Pulse Motor). The first invention in this prior example is as follows: The stator is a flat magnetic material, on the surface of which a square lattice is cut, means for providing protruding teeth of the magnetic material at the intersections of the lattice, and a mover. consists of a five-phase concentrated winding electromagnet, and the magnetic pole surface facing the stator of each electromagnet is provided with protruding teeth of magnetic material at the same pitch as the stator, and the relative positions of each phase electromagnet are as follows: In the X, Y orthogonal coordinate system rotated by an angle tan ^-1 (1/2) with respect to this square lattice, the second phase is
Phase is +X direction, 3rd phase is +Y direction, 4th phase is -X
The fifth phase is 1/1 of the grid pitch in the -Y direction.
A Surf Eight pulse motor characterized by having a means for providing a difference by √5, and a means for supporting the movable element in opposition to the stator with a constant gap and movable in the X direction and the Y direction. .

Further, the second invention is as follows: The stator is a flat magnetic material, and a triangular lattice is cut on the surface thereof, and means for providing protruding teeth of the magnetic material at the intersections of the lattice, and a movable member. The child consists of a seven-phase concentrated winding electromagnet, and the magnetic pole surface facing the stator of each electromagnet is provided with protruding teeth of magnetic material at the same pitch as the stator, and the relative position of each phase electromagnet is , X, Y rotated by an angle tan ^-1 (√3/5) with respect to this triangular lattice,
In the Z oblique coordinate system, with respect to the first phase, the second phase is in the +X direction, the third phase is in the +Y direction, and the fourth phase is in the +Y direction.
Phase is +Z direction, 5th phase is -X direction, 6th phase is -Y
direction, the 7th phase is 1/1 of the lattice pitch in the -Z direction.
A surfboard characterized by having the following: means for providing a difference by √7; and means for supporting the movable element in opposition to the stator with a constant gap and allowing movement in the X direction, Y direction, and Z direction. Eighth pulse motor.

It is.

[Problem that the invention attempts to solve]

However, the conventional surface pulse motor,
There are only models with complicated structures and high prices, such as the XY plotter made by Heuretsu Pats Card (trade company name), which has a linear pulse motor mounted on the Y axis, and is not used very often.

In addition, the command current in the previous example is cosθ _x・
cosθ _y , which is proportional to the product of sine waves, cannot separate the X and Y directions, computation is rather complicated, and control is not easy due to interference between X and Y. It was hot.

Here, the present invention overcomes the difficulties of the conventional example and the preceding example, and the thrust in directions perpendicular to each other,
The purpose of the present invention is to provide a PM type 4-phase Surf Eight motor that commands current in an excitation mode that can be independently controlled and facilitates thrust, speed, and position control.

[Means for solving problems]

In the present invention, the stator is a flat plate made of a magnetic material, and has a plurality of protrusions forming inductor teeth in a square lattice shape at a constant pitch on the surface facing the mover, and the mover has four pieces. A thin plate of permanent magnet magnetized in a lattice-like multipolar manner is attached to the surface of the iron core of each electromagnet facing the stator, and the magnetic poles of the permanent magnet of the mover face the inductor teeth of the stator. and is supported so that it can freely move on a plane through a certain gap, and the relative position of the mover permanent magnet magnetic pole and the stator inductor tooth is the N pole of the permanent magnet of the first electromagnet EP ₁₁ . coincides with the center of the inductor tooth, the permanent magnet of the second electromagnet EP ₂₁ adjacent to the left side of the first electromagnet is N
The position is shifted in the X direction by 1/2 of the pole pitch that is the distance between the pole and the S pole, and the third electromagnet EP ₁₂ adjacent to the lower side of the first electromagnet is shifted in the Y direction by 1/2 of the pole pitch. The fourth electromagnet EP ₂₂ , which is diagonally adjacent to the first electromagnet, is shifted to 1/2 of the pole pitch.
This is a PM type 4-phase Surf Eight motor in which first to fourth electromagnets are arranged at positions shifted in the X direction and Y direction, respectively.

[Effect]

The currents i ₁₁ , _{i 21} , _i 12 , i ₂₂ flowing through the four electromagnets EP 11 , EP ₂₁ , EP ₁₂ , EP ₂₂ are expressed as: i ₁₁ ∝cosθ〓＋cosθ〓 i ₂₁ ∝sinθ〓−sinθ〓 i ₁₂ ∝sinθ 〓＋sinθ〓 i ₂₂ ∝cosθ〓−cosθ〓 The phase of the command current becomes the sum of the sine waves, which makes calculation easy and highly accurate, and allows independent control in the two directions of orthogonal α and β. It is positioned based on the lattice pitch of the inductor teeth.

Note that in the phase matrix of the command armature current, when the phase angle in the X direction is θ _x and the phase angle in the Y direction is θ _y , θ〓 and θ〓 are obtained by rotating them by 45 degrees.

〔Example〕

A perspective view (with the electromagnet omitted) showing the external appearance of one embodiment of the present invention is shown in FIG. 1a.
FIG. 1b is a perspective view of one element electromagnet forming a mover. The electromagnet EP ₁₁ (other electromagnets are similar) has a coil 4 ₁₁ concentratedly wound around the central leg of an iron core 3 ₁₁ in which E-shaped cores are laminated, and a lattice-shaped coil on the surface of the iron core 3 ₁₁ facing the stator 1. A multi-pole magnetized permanent magnet ₅₁₁ is attached.

FIG. 2 is a plan view of the stator and mover facing each other with a gap in between, with the armature electromagnets shown in solid lines and the inductor teeth shown in dotted lines.

FIG. 3 is a diagram showing the relationship between the stator coordinate system X-Y and the mover coordinate system α-β.

The stator 1 has magnetic protrusions (hereinafter referred to as inductor teeth) 101, 102, . . . arranged in a square grid shape.
It is a flat plate of magnetic material having 171, .

The mover 2 has four electromagnets EP ₁₁ , EP ₁₂ , EP ₂₁ ,
Consisting of EP ₂₂ , each electromagnet element EP ₁₁ coil 4 ₁₁
As shown by solid lines in FIG. 2, a thin plate of a permanent magnet 5 ₁₁ magnetized in a lattice-like multipolar manner is attached to the cut surface of the iron core 3 ₁₁ which is excited by form.

The mover 2 is supported with a certain gap with respect to the stator 1, with the magnetic poles (N, S, ...) of the permanent magnet 5 facing the inductor teeth 101, ..., and is free to move on a plane. It is configured so that it can be carried out.

The relative position of the electromagnet's magnetic poles to the inductor teeth is as follows: When the N pole of electromagnet EP ₁₁ is aligned with the center of the inductor teeth, electromagnet EP ₂₁ has a pole pitch (distance between N and S poles) in the X direction. The electromagnet EP ₁₂ is shifted by 1/2 of the pole pitch in the Y direction,
Four electromagnets EP ₁₁ , EP ₂₁ , EP ₁₂ , _and EP ₂₂ are arranged so that the electromagnets EP 22 are shifted by 1/2 of the pole pitch in the X direction and the Y direction, respectively.

This state diagram is shown in FIG.

Therefore, the permanent magnet 5 of each armature (mover 2) electromagnet EP for the inductor tooth T as shown in FIG.
At the relative position of the magnetic poles, if the coil 4 ₁₁ of the electromagnet EP ₁₁ is excited so that the inductor tooth becomes the S pole, the N pole of the permanent magnet 5 and the induced S pole of the inductor tooth attract each other, so In this position, the mover 2 is balanced.

When the current i ₁₁ of the electromagnet EP ₁₁ is cut off and the current i ₂₁ of the electromagnet EP ₂₁ is applied, the mover 2 moves 1/2 in the right (X) direction.
The magnetic pole pitch moves and stops.

Alternatively, when a current is applied to the electromagnet EP ₁₂ , the mover moves downward (-Y) by 1/2 magnetic pole pitch.

In this way, by switching the electromagnets EP _jk (j, k are 1 or 2) one after another, thrust can be generated in any direction and the mover 2 can move above the stator 1.

The expression representing the thrust force generated in the mover 2 can be obtained as follows.

The magnetic flux _B a created by the magnetomotive force of armature electromagnet EP _jk is
It is modulated by the inductor tooth T and distributed as follows.

B _a = B _n (1 + K ² cos2π/λx・cos2π/λy) ... (1 formula) where B _n is the maximum magnetic flux amplitude created by the magnetomotive force of the armature electromagnet, λ is the pole pair pitch, and K ² is the magnetic field modulation. The ratio x, y is the coordinate value (length) of the X-Y coordinate.

The magnetomotive force created by the magnetic poles of the permanent magnet 5 is expressed as a magnetizing current i _f as follows: i _f =2H _c L _n (Equation 2).

Here, H _c is the coercive force of the permanent magnet 5, and L _n is the thickness.

The magnetizing current i _f flows in a square loop with one side of λ/2 (as shown in Figure 2).

If the total magnetic flux due to the magnetomotive force B _a of the armature electromagnet surrounded by this loop is φ, the thrust forces F _x and F _y are F _x = i _f dφ/dx F _y = i _f dφ/dy.

Therefore, considering i _f φ=U as the thrust potential, U=4i _f B _n K ² (λ/2π) ² cos2π/λx・cos2π/λ
y...(Equation 3) is obtained.

The magnetomotive force B _n caused by each electromagnet will be expressed as B _jk , and its potential will be expressed as U _jk .

Here, the magnetomotive force B _jk is given as follows.

B ₁₁ = B _n cosθ _x・cosθ _y B ₂₁ = B _n sinθ _x・cosθ _y B ₁₂ = B _n cosθ _x・sinθ _y B ₂₂ = B _n sinθ _x・cosθ _y ... (4 formula) Potential at this time U is U=U ₁₁ +U ₂₁ +U ₁₂ +U ₂₂ , that is, U=4i _f BmK ² (λ/2π) ² cos(θ _x −2π/λx) cos(
θ _y −2π/λ y) ...(Equation 5).

X in the phase matrix of the commanded armature current
It is clear that if the phase angle in the direction θ _x and the phase angle in the Y direction are θ _y and those θ _x and θ _y are commanded, the movable element 2 moves to that position and becomes balanced.

However, it is necessary to create and command an armature current i _jk that creates a magnetic flux as expressed by equation (4).

The phase matrix of the armature current can be expressed as cos θ _x · cos θ _y , sin θ _x · cos θ _y , cos θ _x · sin θ _y , sin θ _x · sin θ _y ... (equation 6) from (equation 4).

The coordinates (θ _x , θ _y ) of stator 1 are set to the next mover 2.
Coordinates are converted to the coordinates (θ〓, θ〓).

θ _x + θ _y = θ〓 θ _x −θ _y = −θ〓} ...(Equation 7) Then, the phase matrix is 1/2cosθ〓+COSθ〓, sinθ〓−sinθ〓, sinθ〓+sinθ〓 cosθ〓−cosθ〓 ... ...(Equation 8) becomes.

The coordinates of (θ〓, θ〓) are the coordinates of (θ _x , θ _y ) rotated by 45 degrees (Fig. 3) and the dimensions multiplied by 1/√2, and the tooth pitch (pole-to-pole pitch) is λ /√2 (Figure 2).

This means that positioning is performed based on the lattice pitch λ/√2 of the inductor teeth T (101, 102, . . . ) rather than the pole pair pitch λ/2 of the magnetic poles of the permanent magnet 5.

The method of determining the command current i _jk from θ and θ in equation (8) is easy to calculate because it is in the form of a sum rather than a product of sine waves as in equation (6).

Also, (cosθ〓, sinθ〓), (cosθ〓, sinθ〓)
If we divide it into , (8) can be written as cosθ〓 00 cosθ〓+0 sinθ〓sinθ〓 0+cosθ〓 00 −cosθ〓+0 sinθ〓−sinθ〓 0. Since these four current components flow without interfering with each other, (cos θ〓, sin θ〓) serves as a linear motor in the α direction, and (cos θ〓, sin θ〓) serves as a linear motor in the β direction.

Next, as another embodiment of the present invention, there is a means of adding two of cos θ〓, sin θ〓, cos θ〓, and sin θ〓 to the winding of each electromagnet to create a command current phase using an operational amplifier. .

Furthermore, as another embodiment of the present invention, _the armature electromagnet winding w _jk is connected as shown below, and each phase signal is separated and _independent . Connect 1/2 of the winding w ₁₁ of ₁₁ and 1/2 of the winding w _{22 of electromagnet EP 22 in} in-phase series to obtain cos θ〓.

Similarly, 1/2w ₂₁ +1/2w ₁₂ →sinθ〓 1/2w ₁₁ −1/2w ₂₂ →cosθ〓 Here, −1/2w ₂₂ means that 1/2 of the windings are connected in reverse phase series. and 1/2w ₁₂ −1/2w ₂₁ →sinθ〓.

[Effect of idea]

Thus, according to the present invention, a PM type 4-phase surf-eight motor that is economical and has significantly improved reliability can be obtained because it exhibits the following many remarkable effects.

In other words, since the phase of the command current is the sum of the sine waves, calculations become easier and accuracy can be increased.

Two orthogonal directions α and β can be controlled independently.

Since positioning can be performed based on the lattice pitch of the stator teeth, it is easy to achieve accuracy.

Since the position of the winding of each electromagnet and the distribution of current are symmetrical in both the α direction and the β direction, the positioning accuracy is improved.

By setting the excitation mode of the phase of θ〓 or θ〓 to zero, it is possible to perform linear restraint that allows movement only in that direction.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of an embodiment of the present invention;
FIG. 2 is an opposing plan view showing lattice coordinates formed by stator protrusions and mover magnetic poles, and FIG. 3 is a diagram showing the relationship between the stator coordinate system and the mover coordinate system. 1... Stator, 101, 102,..., 171
... Stator projection (inductor tooth), 2 ... Mover, 3 _1
1 ...Iron core, 4 ₁₁ ...Coil, 5 ₁₁ ...Permanent magnet,
5... Whole permanent magnet.

Claims (1)

[Claims for Utility Model Registration] 1. The stator is a flat plate made of a magnetic material, and has a plurality of protrusions forming inductor teeth in a square lattice shape with a constant pitch on the surface facing the movable element, and is movable. The mover consists of four electromagnets, and a thin plate of permanent magnet magnetized in a lattice-like multipolar manner is attached to the surface of the iron core of each electromagnet facing the stator. It faces the inductor teeth and is supported so that it can freely move on a plane through a certain gap, and the relative positions of the mover permanent magnet magnetic poles and the stator inductor teeth are determined by the first electromagnet EP ₁₁ When the N pole of the permanent magnet coincides with the center of the inductor tooth, the permanent magnet of the second electromagnet EP ₂₁ adjacent to the left side of the first electromagnet is 1/2 of the pole pitch that is the distance between the N pole and the S pole.
The third electromagnet EP ₁₂ , which is adjacent to the lower side of the first electromagnet, is shifted in the Y direction by 1/2 of the pole pitch.
A fourth electromagnet diagonally adjacent from the electromagnet
EP ₂₂ is a PM type 4-phase surf-eight motor characterized in that the first to fourth electromagnets are arranged at positions shifted by 1/2 of the pole pitch in the X direction and the Y direction, respectively. 2 The currents i ₁₁ , i ₂₁ , i ₁₂ , i ₂₂ flowing through the coils of the first to fourth electromagnets wound with the same number of turns are i ₁₁ ∝cosθ〓＋cosθ〓 i ₂₁ ∝sinθ〓−sinθ〓 i ₁₂ ∝ sinθ〓＋sinθ〓 i ₂₂ ∝cosθ〓−cosθ〓 However, θ〓, θ〓 can be commanded and controlled by the synthesis of sine waves having the phases of θ〓, θ〓 like the phase angle of the command position. thrust, motion,
A PM type four-phase surf ace motor according to claim 1 of the utility model registration claim, which performs position control.