JPH0312058Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention uses high-energy magnet material and improves the shape of permanent magnets (hereinafter simply referred to as magnets) to create a compact The present invention relates to a linear pulse motor that realizes a mover (hereinafter referred to as a slider) and can be made smaller and faster.

(Prior Art) Fig. 5 is a structural diagram showing a conventional example of a linear pulse motor, Fig. 6 is a diagram showing the magnetic pole arrangement of the conventional example, and Fig. 7 explains the operating principle of the conventional example. This is a diagram for

In FIG. 5, 1 is a magnet, 2 is a magnetic pole core, 3 is a coil, 4 is a scale, and 5 is a magnetic path plate.

The magnet 1 is used to generate a constant magnetic flux (bias magnetic flux) in the air gap (hereinafter referred to as an air gap) δ between the magnetic pole core 2 and the scale 4 to obtain a magnetic attraction force. The magnet 1 is magnetized in the vertical direction as shown in FIG. A coil 3 is wound around the magnetic pole core 2. By passing a current through the coil 3, the magnetic pole core 2 becomes an electromagnet, and similarly to the magnet 1, it generates magnetic flux in the air gap δ and causes magnetic attraction. You can gain power. The scale 4 is a toothed plate-like member with high magnetic permeability. The magnetic path plate 5 is for preventing the operating point of the magnet 1 from lowering.
It is made of ferromagnetic material such as iron plate. A magnet 1, a scale 2, and a magnetic path plate 5 constitute a slider.

In FIG. 6, pitch p indicates the tooth pitch of the magnetic pole core 2 and the tooth pitch of the scale 5.

The A-phase magnetic pole A and the B-phase magnetic pole and B of the magnetic pole core 2 are arranged to be shifted by np±(1/2)p (n: integer), respectively. Also, the magnetic pole and B are
They are arranged with a shift of np±(1/4)p. the result,
The magnetic pole A and the magnetic pole are shifted by np±(1/4)p.

The coils 3A and 3 and the coils 3B and 3 are wires of the same thickness and wound the same number of times, but the winding directions are opposite to each other, and they are connected in series. Therefore, when current is passed through these coils, the polarities of N and S are reversed.

Next, the operation of a conventional linear pulse motor will be described with reference to FIG. Note that this operates based on Sawyer's principle.

In FIG. 7, it is assumed that the magnetic flux generated by the magnet 1 is Φm, and the magnetic flux generated by the magnetic poles A and B of the magnetic pole core 2, which serve as electromagnets, is Φe.

As shown in Figure 7a, when a coil current is passed through the coils 3B and 3, the magnetic flux Φm is 2 at the magnetic pole A.
divided. However, at magnetic pole B, the magnetic flux becomes Φm + Φe, and the slider is strongly restrained at the position of magnetic pole B.
At the magnetic pole, the direction becomes Φm - Φe and the direction is canceled.

Next, as shown in FIG. 7b, the coils 3A, 3
When a current is applied to the slider, the slider is held at the magnetic pole position. Similarly, in Figure 7c, at the position of the magnetic pole,
In FIG. 7d, the slider is restrained at the position of the magnetic pole A, and the slider sequentially moves to the right by (1/4)p.

Furthermore, when the direction of current flow is reversed, the cells sequentially move to the left by (1/4)p.

(Problem to be solved by the invention) In a conventional linear pulse motor, a vertically magnetized magnet 1 is arranged on a pair of magnetic pole cores 2, and a magnetic path plate 5 is further provided on top of the magnet 1, and the slider As a result, the slider became large, which was an obstacle to miniaturizing and increasing the speed of linear pulse motors.

In addition, since the magnetic poles A and B of the magnetic pole core 2 constituting the slider are independent, it is difficult to accurately measure the spacing of np±(1/4)p during assembly, even if a jig is used. Even when I used it, it was difficult. If this deviation of np±(1/4)p is not accurate, the accuracy of step movement will deteriorate.

An object of the present invention is to provide a linear pulse motor that enables high-speed response by reducing the weight and size of the slider.

(Means for Solving the Problems) In order to achieve the above object, a linear pulse motor according to the present invention includes a scale in the form of a toothed plate, and a slider disposed with a gap between the scale and the linear pulse motor. The first and second sliders are arranged such that the magnetic pole arrangement of the slider is shifted by 1/4 pitch, and the front side and the back side are opposite to each other.
The cross section of the magnetic pole core and the portion sandwiched between each of the magnetic pole cores is a U-shaped integral shape and has a T-shaped vertical cross section, and the vertical cross section is magnetized symmetrically in the front and back directions. It consists of a permanent magnet molded from high-energy magnetic material.

The permanent magnets can be formed from high energy magnetic materials such as rare earth magnets or rare earth plastic magnets.

The pitch of the teeth of the magnetic pole core may be equal to or different from the pitch of teeth of the scale.

(Example) The present invention will be described in detail below with reference to the drawings and the like.

FIG. 1 is a structural diagram showing an embodiment of the linear pulse motor according to the present invention, FIG. 2 is a diagram showing the magnetic pole arrangement of the motor of the embodiment, and FIG. 3 is an illustration of the operating principle of the motor of the embodiment. In order to facilitate understanding, the upper side of the T-shaped longitudinal section of the permanent magnet is omitted in each figure.

FIG. 4 shows a perspective view of an embodiment of the permanent magnet used in the present invention.

In FIG. 1, 11 and 12 are magnets, 21 and 22 are magnetic pole cores, 3 is a coil, and 4 is a magnet.
is the scale.

The magnets 11 and 12 function to generate a constant magnetic flux Φm, and the coil 3 wound around the magnetic pole cores 21 and 22 functions to generate a magnetic flux Φe due to the electromagnet in the magnetic pole cores 21 and 22.

The magnets 11 and 12 are made of a high-energy magnetic material, such as a rare earth magnet or a rare earth plastic magnet.

The magnets 11 and 12 are formed into a U-shape and are magnetized in the front and back directions as shown in FIG. The reason why the magnets 11 and 12 are formed into a U-shape is that the cross-sectional area of the magnets 11 and 12 can be increased even in the limited space of the slider. Note that the one-dot chain line in FIG. 1 is the center line of the magnetic pole of the magnet 11. Moreover, if the magnets 11 and 12 are made into a U-shape and molded from rare earth plastic magnet material, they can be easily manufactured in large quantities.

By optimally designing the thickness and cross-sectional area of the magnets 11 and 12, the necessary magnetic flux can be obtained without lowering the operating point of the magnets 11 and 12. As a result, the slider can be made more compact and high-speed response can be achieved. In other words, if the force required for acceleration is F, the slider weight is m, and the acceleration is α, then the relationship is F = mα, so if the force F required for acceleration is constant, by reducing the slider weight m, , the acceleration α can be increased.

As shown in FIG. 2, the pitch p is
1, 22 and scale 4 tooth pitch.
In this embodiment, the tooth pitch of the slider and the scale 5 are
The pitches of the teeth are the same (p=p ₁ ).

The centers of the teeth 21a, 22a of the magnetic poles A, B, . Moreover, the center of the magnetic pole yokes 21b, 22b of the magnetic pole iron cores 21, 22 and the magnetic pole teeth 21a,
The center of 22a is shifted by (1/4)p.

In addition, as shown in the arrow view of FIG. 2 aX-X shown in FIG. The magnets 11 and 12 are sandwiched between the magnetic pole cores 21 and 22, and the magnetic pole yoke portion 21
b, 22b are assembled in a sandwich structure with opposite directions.

The magnetic pole arrangement of the magnetic pole iron cores 21 and 22 is shifted at equal intervals of (1/4) p, and the magnetic pole intervals of magnetic pole A and magnetic pole B are every other, and the length of the magnetic circuit is constant. Therefore, the structure is such that it is not easily affected by variations in the characteristics of the magnet. For this reason,
The suction forces in the air gap δ are balanced. As a result, there is little variation in the holding force and moving force (thrust) of the slider due to switching of excitation. In other words, Fig. 3 a, b, c, which will be described later,
It is possible to reduce variations in holding force at each holding position of d.

The magnetic pole cores 21 and 22 have a structure in which they are assembled in opposite directions. Therefore, when the magnetic pole cores 21 and 22 are manufactured by press punching or the like, dimensional errors can be canceled out, and the accuracy of the slider holding position can be improved. Furthermore, since the magnetic pole cores are connected, when the magnetic pole cores are processed using a press or the like, they can be held with the precision of the press, so positioning of the magnetic poles is not necessarily necessary, making assembly easier.

In scale 4, the magnetic flux Φm of the magnets 11 and 12 is determined by the magnetization direction, and is from the front to the back of the paper (or from the back to the front), and the magnetic flux Φe of the electromagnet is determined from the front to the back of the paper, or from the back to the front, depending on the direction of the current. The direction alternates from the back to the front. In other words, the direction is 90 degrees from the direction of movement of the slider (Fig. 2c). In this way, the length of the magnetic path remains constant even if the phase excitation is changed, so that the holding force does not change due to a change in the length of the magnetic path.

Next, the operation of the linear pulse motor according to the present invention will be explained.

As shown in Figure 3a, the coil 3
When a current flows through A and 3, the magnetic flux becomes Φm + Φe at the magnetic pole A, and the magnetic pole A of the magnetic pole core 21 on the front side
At the same time, the magnetic flux at the magnetic pole becomes Φm+Φe, and the slider is held in the position shown in FIG. 3a because it is restrained by the teeth of the magnetic pole core 22 on the back side.

Next, when current is applied to the coil in the direction of the arrows in Figures 6b, 6c, and 6d, the holding position of the slider moves in the direction of the arrows based on the same principle as in Figure 6a. Moving. The interval of movement is (1/4) p
Therefore, it is possible to operate the motor in a manner compatible with the conventional linear pulse motor.

In addition, in FIG. 2, only the tooth pitch p ₁ of the magnetic pole cores 21 and 22 can be made p≠p ₁ . However, if the pitch p ₁ of the magnetic pole iron cores 21 and 22 is set larger than the pitch p of the scale 4, but when considering the magnetic pole A as a reference, if the pitch p ₁ is set too large,
It may interfere with the teeth of the magnetic poles B, . . ., resulting in increased magnetic flux leakage and a loss in holding force. For this reason, the magnetic pole core 2 that constitutes the slider
If the optimum pitch p ₁ is given by taking into account manufacturing errors in the tooth width and tooth pitch of scales 1 and 22 and scale 4, the air gap magnetic flux at each magnetic pole tooth becomes close to a sine wave, and the direction of movement of the slider The slope of the holding force becomes close to a sine wave. Considering the above, in this embodiment, as an example, p ₁ > (1 to 1.04)
It is about p.

FIG. 4 is a perspective view showing a magnet used in the linear pulse motor according to the present invention, and the magnet 11 has a T-shaped cross section. This is to strengthen the slider holding force and thrust. Note that the one-dot chain line in FIG. 4 is the center line of the magnetic pole of the magnet 11.

The linear pulse motor according to the present invention can be suitably used in applications such as microstep drives that require a sinusoidal slope of holding force.

(Effects of the invention) As explained in detail above, according to the invention,
Since the slider can be made lighter and smaller, it is possible to realize a linear pulse motor that enables high-speed response.

Furthermore, since the magnetic pole cores are connected, when the magnetic pole cores are processed using a press or the like, they can be held with the precision of the press, so positioning of the magnetic poles is not necessarily necessary, making assembly easier.

Furthermore, since the length of the magnetic path is constant, the holding force can be kept constant.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram showing an embodiment of the linear pulse motor according to the present invention, FIG. 2 is a diagram showing the magnetic pole arrangement of the motor of the embodiment, and FIG. 3 is an illustration of the operating principle of the motor of the embodiment. This is a diagram for Fourth
The figure shows another embodiment of the magnet used in the linear pulse motor according to the present invention.
FIG. 5 is a structural diagram showing a conventional example of a linear pulse motor, FIG. 6 is a diagram showing the magnetic pole arrangement of the conventional example, and FIG. 7 is a diagram for explaining the operating principle of the conventional example. . 1... Magnet, 2... Magnetic pole iron core, 3... Coil, 4... Scale, 5... Magnetic path plate, 11,1
2...Magnet, 21, 22...Magnetic pole iron core.

Claims (1)

[Claims for Utility Model Registration] (1) In a linear pulse motor consisting of a tooth-shaped plate-shaped scale and a slider arranged with a gap from the scale, the magnetic pole arrangement of the slider is shifted by 1/4 pitch to the front side. The cross section of the portion sandwiched between the first and second magnetic pole cores, which are arranged with their back sides facing oppositely, is U-shaped and has a T-shaped vertical cross section. What is claimed is: 1. A linear pulse motor comprising a permanent magnet molded from a high-energy magnetic material, the longitudinal section of which is magnetized symmetrically in the front and back directions. (2) The linear pulse motor according to claim 1, wherein the permanent magnet is formed of a high-energy magnetic material such as a rare earth magnet or a rare earth plastic magnet. (3) The linear pulse motor according to claim 1, wherein the tooth pitch of the magnetic pole core is different from the tooth pitch of the scale. (4) The linear pulse motor according to claim 1, wherein the tooth pitch of the magnetic pole core is different from the tooth pitch of the scale.