JPH01286766A - Stator for permanent magnet linear stepping motor - Google Patents

Abstract

PURPOSE:To easily select the length of a stator by combining magnetic pieces and nonmagnetic pieces of accurate sizes, alternately superposing them, and disposing them between the parallel parts of a U-shaped frame. CONSTITUTION:Frames 15, 15a made of U-shaped magnetic pieces of a stator are so clamped with bolts 16 on a magnetic base 12 as to direct the parallel parts toward the longitudinal direction of the base 12. The frames 15, 15a have a protrusion at U-shaped connecting end, a recess is formed at its opening end, magnetic pieces 17 and nonmagnetic pieces 18 having the same thickness are so alternately vertically filled between the parallel parts of the frame 15 as to form pectinated magnetic teeth in the same plane as that of the upper surface of the frame. In this case, the pieces 17, 18 are held in advance in an accurate size by machining. Further, the frame 15a is similarly formed, clamped together with a retaining plate 19 with a bolt 20 passing the parallel parts of the two frames 15, 15a, and secured integrally with the base 12. Thus, the length of the stator can be altered by the size or the like of the frame itself.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is widely used in information equipment, automated machinery, etc.
This invention relates to a permanent magnet type linear step motor in which a mover reciprocates on a stator.

[Conventional technology]

FIG. 4 shows a cross-sectional view of a conventional permanent magnet type linear step motor to explain its structure and operation. In FIG. 4, a plate-shaped permanent magnet 1 has a bank plate (yoke) 2 on its upper surface, and a mover yoke 3 on the opposite surface.
and 5 are fixed with the gap 11 maintained, and the mover yoke 3
and 5 are each provided with a wheel 10 at one end, and these wheels 10 are in contact with the stator 4 which serves as a rail. The permanent magnet 1 is magnetized so that the right half, that is, the movable element yoke 5 side, and the left half, that is, the movable element yoke 3 side in FIG. The back plate 2 remains, and the mover yoke 3. It passes through the stator 4 and the movable yoke 5 in this order and returns to its original position.

On the other hand, the movable element yoke 3 has two magnetic poles 6a and 6b, which form a pair.
are provided so as to face the stator 4 with a slight gap 15 maintained at their tips, and the magnetic poles 6a and 6b are provided with @ wire portions 7a and 7b, respectively. This state is exactly the same for the movable yoke 5, and in the movable yoke 5, the magnetic poles 6c, 6d and the winding portions 7c, 7 wound around these poles 6c, 6d.
d. Further, a plurality of magnetic teeth are formed at the tip of each magnetic pole 6a to 6d facing the stator 4 with a pitch of τ, and hereinafter these will be simply referred to as magnetic teeth corresponding to the signs of the magnetic poles 6a to 6d. The distance between the magnetic teeth 8a and 8b on the movable element yoke 3 side and the distance between the magnetic teeth 8C and 8d on the movable element yoke 5 side, expressed as teeth 8a to 8d, are both τ, (
, + 0.5), and the distance between the magnetic teeth 8b and 8C from the movable platen 3 to the movable yoke 5 is τp (n+0.
25) are arranged so that the following relationship holds true. Cabinet,
n is any integer.

On the other hand, the stator 4 has many magnetic teeth 8a to 8d and a gap 1.
A large number of slits are cut on the surfaces facing each other at a distance from each other to form a comb-like shape, and the peaks of the slits are formed into magnetic teeth (hereinafter referred to as comb-shaped magnetic teeth 9). It is formed. The pinch of the comb-shaped magnetic teeth 9 is also the same as that of the magnetic teeth 8a to 8d provided on the movable element yoke 3.5.

The two wheels 10 have magnetic teeth 8a to 8d and comb-shaped magnetic teeth 9.
The gap 11 is formed between the movable yoke 3 and the movable yoke 5, and has the role of making the movable yoke 3 and the movable yoke 5 run while maintaining a gap 15 facing each other at a constant interval. This is to prevent the magnetic flux generated from the permanent magnet 1 from being short-circuited and to allow the magnetic flux to pass through a predetermined magnetic circuit. Further, illustrations of electrical control systems and the like associated with this device are omitted.

The configuration of the permanent magnet type linear step motor has been outlined above with reference to FIG. 4, and now its operating principle will be explained. In the linear step motor, magnetism is generated between magnetic teeth 8a to 8d formed on the magnetic poles 6a to 6d of the movable yokes 3 and 5 and a large number of magnetic teeth consisting of comb-shaped magnetic teeth 9 formed on the stator 4. The force moves the mover in steps, and the stepping force is proportional to the difference in the amount of magnetic flux passing between the opposing magnetic teeth, and the accuracy of the amount of one step and the stop position is determined by the magnetic teeth 8a to 8d and the comb tooth shape. It is governed by the geometrical relative position with the magnetic teeth 9 and their machining accuracy.

In FIG. 4, t! By connecting the striped portions 7a and 7b with opposite polarity and passing a current from a control circuit (not shown) through them, the magnetomotive force due to the stripes 7a increases the magnetic flux generated from the permanent magnet 1, and the magnetomotive force due to the winding 7b increases. When working to reduce the magnetic flux generated from the permanent magnet 1, the relative geometrical positions of the magnetic teeth 8a and the comb-shaped magnetic teeth 9 are as shown in FIG. Since the amount of magnetic flux passing through the magnetic teeth 8a and the comb-shaped magnetic teeth 9 is large, the magnetic force is increased, and the magnetic resistance at that part is minimized, that is, the opposing teeth and grooves are directly opposed to each other. become. In addition, since the amount of magnetic flux passing through the magnetic teeth 8b and the comb-shaped magnetic teeth 9 decreases, the magnetic force is small, and the magnetic teeth 8b
is 0, where the tooth and groove face each other directly due to the magnetic force acting on the magnetic tooth 8a.
, the position is shifted by a pitch of 5τ.

On the other hand, a winding portion 7 is provided between the magnetic teeth 8c and 8d and the comb-shaped magnetic teeth 9.
Since no current is flowing through the magnetic teeth c and 7d, no magnetic force is generated, and due to the distances between the magnetic teeth 8b and 8c and the magnetic teeth 8c and 8d mentioned above, the positional relationship is such that the magnetic tooth 8c is the comb-shaped magnetic tooth 9. and 0.75τ, pitch, magnetic tooth 8d is comb-shaped magnetic tooth 9 and 1.2
The position is pitch shifted by 5τ.

Here, the winding portions 7c are connected to each other so as to have opposite polarities,
Using a control circuit (not shown) in 7d, the magnetomotive force by the winding part 7d increases the magnetic flux generated from the permanent magnet 1, and the magnetomotive force by the winding part 7c decreases the magnetic flux generated from the permanent magnet 1. A current is applied, and at the same time the winding part is 7 m long,
When the current flowing through the magnetic teeth 7b is cut off, the amount of magnetic flux passing through the magnetic teeth 8d and the comb-shaped magnetic teeth 9 increases, and the amount of magnetic flux passing through the magnetic teeth 8c and the comb-shaped magnetic teeth 9 decreases. The magnetic force between the comb-shaped magnetic teeth 9 is larger than that on the magnetic teeth 8c side,
The movable element moves to the position where the magnetic resistance is minimum, that is, the position where the teeth and grooves face each other, and then stops.

At this time, the direction in which the mover moves is from right to left in FIG. 4, and the amount of movement is as described above (the relative positional deviation between the magnetic teeth 8d and the comb-shaped magnetic teeth 9 is 0.25τ).

Since it was a pinch, the amount of movement until these teeth face each other accurately is 0.25τ, and the magnetomotive force of the winding part 7b is generated from the control circuit (not shown) to the permanent magnet. 1, and a current is passed so that the magnetomotive force of the winding part 7a decreases the magnetic flux of the permanent magnet 1, and the magnetic flux of the winding part 7c is increased.
, 7d is cut off, the relative position of the magnetic tooth 8b and the comb-tooth magnetic tooth 9 in the pre-operation is the same as that of the magnetic tooth 8d before the pre-operation and the comb-tooth-shaped magnetic! It is in the same position as No. 19, and the mover moves 0.25τ to the left in Fig. 4.

Pinch move.

As described above, the linear step motor shown in FIG. 4 selects the direction of the current flowing through the windings 7a to 7d from a control circuit not shown, determines the polarity of the magnetic poles 6a to 6d, and controls the current intermittently. By doing so, highly accurate stepping motion can be performed.

By the way, in general, when using a linear step motor, the stop position accuracy for each step operation is one of the most important performances, and the linear step motor with the structure shown in Figure ◆ has magnetic teeth 8a for step operation and stop position. ~8d and comb-shaped magnetic tooth 9
The stopping position accuracy is determined by their relative position accuracy. This relative position accuracy is determined by the magnetic teeth 8a to 8.
d and the processing accuracy of the comb-shaped magnetic teeth 9.

Here, a method of processing the comb-shaped magnetic teeth 9 formed on the stator 4 will be described. FIG. 5 is a plan view showing only the stator 4, and FIG. 6 is a sectional view thereof.

In both figures, the same reference numerals are used for parts common to those in FIG. 4. As shown in FIG. 5, the stator 4 has holes formed by press punching or photoetching to form comb-shaped magnetic teeth 9 having a pitch of τ, but FIG. This is a case in which the magnetic body 11 is adhesively fixed onto a base 12 which is also made of a magnetic body and is not shown in the figure.

On the other hand, FIGS. 7 and 8 similarly show a plan view and a sectional view of the stator 4, and the plan view in FIG. 7 is exactly the same as that in FIG. The tooth-shaped magnetic teeth 9 are formed by photo-etching, and therefore, as shown in FIG. 8, a plurality of perforated magnetic bodies 13 are laminated and bonded onto the base 12. In this way, the stator 4 can have the comb-shaped magnetic teeth 9 formed by press punching or photo etching, but since the magnetic flux path in a linear step motor is the same, the stator 4 can be fabricated using either of these methods. is used.

[Problem to be solved by the invention]

The structure and operation of the permanent magnet type linear step motor and the production of the stator 4 have been described above, but the problem is the pitch τ of the comb-shaped magnetic teeth 9 formed on the stator 4.

The aim is to control the In other words! When trying to manufacture a precision linear step motor with a small stepping distance, high precision can be expected by machining the mover side, but the pitch τ of the comb-shaped magnetic teeth 9 on the stator side is set to be quite small. This is because it is not possible to obtain a stator that fits the grooves using the conventional processing method described above, and the reason for this is as follows.

First, when forming the comb-shaped magnetic teeth 9 by press punching, when the slit length is about 20 m in FIG.
The limit is 2 m. The pitch τ of the perfectly comb-shaped magnetic teeth 9,
is a maximum of 0.4, so it is impossible to obtain a precision linear step motor with a movement distance of 0.4 m x 0.25-0 or less than 1 crane. When forming the teeth 9, it is possible to control the pitch error to the micron level by setting the thickness of the magnetic material 13 shown in FIG. 8 to 0.5 mm or less. However, in this case, the step feed action of the linear motor is to form a loop in which the magnetic flux flows from the magnetic teeth 88 to 8d (Fig. 4) of the stator to the comb-shaped magnetic teeth 9, but the comb-shaped magnetic teeth 9 have a predetermined height. Therefore, it is common to use a plurality of magnetic bodies 13 stacked together using an adhesive. Each magnetic material 1 with holes made by etching
3 on the magnetic base 12 shown in FIG. 8, after applying an adhesive, the necessary number of sheets are stacked along the guide and the adhesive is hardened. However, the process of bonding a large number of thin plates having slits in which the comb-shaped magnetic teeth 9 are formed at very narrow intervals to the thin magnetic plate 13 causes the comb-shaped magnetic teeth 9 to be curved and deformed. This reduces the pitch accuracy of the comb-shaped magnetic teeth 9.

As described above, the comb-shaped magnetic teeth 9 are formed in order to reduce the pitch τ of the comb-shaped magnetic teeth 9 formed on the stator 4 of the linear step motor to obtain a precision linear step motor with a short moving distance per step. If this is done by press punching, the pitch dimension is up to 0.4 Tsuru, and if etching is performed below that, the pitch accuracy will deteriorate, so in any case, the conventional method yields a satisfactory stator. I can't.

The present invention has been made in view of the above-mentioned points, and its object is to provide a stator for an orthogonal flux type linear step motor with high precision and a small pitch dimension.

[Means to solve the problem]

The stator of the present invention has a frame made of a U-shaped magnetic material fixed on a magnetic material base with its parallel portions in the longitudinal direction of the base,
A comb-shaped magnetic tooth is created by alternately filling a large number of magnetic pieces and non-magnetic pieces of the same thickness in the space between the parallel parts of the frame so that the thickness surface is flush with the top surface of the frame. The convex portion and the concave portion of the U-shaped frame having the same shape can be fitted into each other, and the frames on which magnetic teeth are formed can be connected to each other. .

[Effect]

As described above, the present invention forms the comb-shaped magnetic teeth of the stator by alternately arranging magnetic pieces and non-magnetic pieces of the same thickness in the frame, so the magnetic tooth pitch is The thickness is determined by these thicknesses, and the pitch of the magnetic teeth can be reduced by accurately manufacturing the thickness by machining in advance. Furthermore, since the frames can be connected to each other through the convex portion and the concave portion, the length of the stator can be easily changed.

〔Example〕

The present invention will be explained below based on examples.

FIG. 1 shows a plan view of the stator of the present invention viewed from above.
In FIG. 1, 15 and 15a are frames made of the same U-shaped magnetic material, and bolts 16 are mounted on the base 12 so that the parallel portions face the longitudinal direction of the magnetic base 12.
It is fixed with. The frame 15° 15a has a convex portion at the U-shaped connecting end, and a concave portion at the open end.
It is possible to fit the protrusion of the frame 15a into the recess at the open end of the frame 15. To form the comb-shaped magnetic teeth, frame 1
5, magnetic pieces 17 and non-magnetic pieces 18 having the same thickness are alternately filled in a direction perpendicular to the parallel part of the frame 15. The thickness surface of the frame body 15 is made to be the same as the upper surface of the frame body 15. In FIG. 1, only the magnetic piece 17 is shown with diagonal lines. The dimensions of the magnetic piece 17 and the non-magnetic piece 18 must be maintained with high precision by machining in advance. The same thing is done for the frame 15a, and the convex part of the linking part of the frame 15a is fitted into the concave part of the open end of the frame body 15, and then the magnetic material having the convex part is placed in the concave part of the open end of the frame body 15a. The presser plates 19 of the two frames 15.15a and the presser plates 19 are fastened together using bolts 20 passing through the parallel parts of the two frames 15.15a, and both the frame bodies 15.15a and the presser plates 19 are attached to the base using bolts 16. It is fixed to 12 and made into one piece. Magnetic piece 17
and the non-magnetic material pieces are pressed and brought into close contact, and the frames 15 and 15
A magnetic body 15a is interposed in the joint portion a to maintain a required magnetic tooth pitch. Magnetic piece 17 and non-magnetic piece 18
The thickness can be up to about 0.1 xs, so a magnetic tooth pitch of 0.2 m can be obtained with high accuracy.

As described above, the stator of the present invention has magnetic material pieces 17 between the parallel parts of the two frame bodies 15.15 m each having uneven parts.
and non-magnetic material pieces 18 are arranged alternately in a predetermined quantity, and the frame body 15 is
and 15a can be connected using the concave and convex portions, so the length of the stator can be changed depending on the dimensions of the frame itself or the number of frames used. Figure 2 shows an example of this, in which a frame 15b is added to the stator in Figure 1.
The length of the stator is extended by connecting them using long bolts 20a. All other parts are the same as those in FIG. 1, so the explanation will be omitted. It goes without saying that it can also be used with only one frame.

FIG. 3 is a sectional view of the central portion of FIG. 1 using the same reference numerals as in FIG. 1 in order to show the shape of the stator of the present invention in the height direction, and the explanation thereof will be omitted.

〔Effect of the invention〕

Conventionally, the stator of a permanent magnet type linear step motor has had comb-shaped magnetic teeth formed by punching out a magnetic plate with a press or drilling holes by photo etching and providing a large number of slits. There is a limit to reducing the vL tooth pitch, and although it is possible to reduce the barge pinch by etching, there is a decrease in accuracy due to the deformation of the magnetic teeth. Whereas I couldn't get a step motor,
As described in the examples, the stator of the present invention does not directly process only magnetic plates to form magnetic teeth, but combines magnetic pieces and non-magnetic pieces finished with highly accurate dimensions. By placing these alternately stacked on top of each other between the parallel parts of the U-shaped frame, the thickness surfaces exposed on these surfaces were flush with the top surface of the frame, resulting in comb-shaped magnetic teeth. Since the pitch dimension of is determined by the thickness dimension of the magnetic material piece and the non-magnetic material piece, it is possible to reduce the magnetic tooth pitch to about 172 compared to the conventional one and obtain a linear step motor that performs precise stepping motion. can. Furthermore, since the convex portion formed at the connecting end of the U-shaped frame body and the concave portion formed at the open end allow the frames to be connected to each other, the length of the stator can be easily adjusted as required. This has the advantage of being selectable.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the stator of the present invention, Fig. 2 is a plan view showing a modified example, Fig. 3 is a sectional view of Fig. 1, and Fig. 4 is a main part of the orthogonal magnet type linear step motor. 5 is a sectional view, and FIG. 5 is a partial plan view of a stator manufactured by press punching.
The figures are the same (partial sectional view, Fig. 7 is a partial plan view of a stator fabricated by photoetching, and Fig. 8 is a partial sectional view of the same. 4: stator, 9: comb-shaped magnetic teeth, 15.15a , 15b
: Frame, 16.20, 20a : Bolt, 17: Magnetic piece, 18: Non-magnetic piece, 19: Holding plate. 17 Shoulder 1 Life Stop Agency Figure 1 Figure 2 Figure 3 Figure 6 Figure 8

Claims (1)

[Scope of Claims] 1) A mover yoke in which a plurality of magnetic teeth are provided at the tips of two sets of magnetic poles that operate in pairs, and a winding portion is attached to each of the magnetic poles, and this mover The stator includes a plate-shaped permanent magnet connected to a yoke, a back plate, and a large number of comb-shaped magnetic teeth facing each of the magnetic teeth at the tip of the magnetic pole with a predetermined gap therebetween. A stator of a permanent magnet type linear step motor that performs stepping motion by magnetic flux generated by a winding portion and magnetic force generated in the air gap in a magnetic circuit, the stator comprising: i) one main surface of a rectangular magnetic base; Parallel parts are fixed along the longitudinal direction of this base, one end forms a convex part and is connected, the other end forms a concave part and is open, and in the same shape, the convex part and the concave part are connected. ii) a frame made of a U-shaped magnetic material that can be fitted and connected to each other; and ii) a surface of one thickness perpendicular to the parallel portion of the frame is arranged at an interval between the parallel portions of the frame and the upper surface of the frame. a plurality of magnetic material pieces and non-magnetic material pieces each having the same thickness and filled in a predetermined quantity alternately so as to be on the same surface; 1. A stator for a permanent magnet type linear step motor, comprising: a magnetic material piece; and a holding plate made of a magnetic material having a convex portion that fixes the non-magnetic material piece in close contact with each other.