JPS60229667A - Linear pulse motor - Google Patents

Abstract

PURPOSE:To improve the magnetic flux efficiency and to improve the response of a linear pulse motor by contacting a pair of poles with a permanent magnet, and providing an exciting coil for exciting the poles. CONSTITUTION:The surfaces of platelike poles 17-20 are polarized as pole surfaces, which are concentrically disposed, and a permanent magnet 33 is contacted with a pair of poles 17-20. The poles 17-20 are excited by exciting coils 27, 28. The relative positions of the teeth 17c-20c and the teeth 42a of a scale 42 are displaced by 1/4 pitch on the basis of the mutual action of the magnetic flux of the permanent magnet 33 and the magnetic fluxes generated by exciting coils 27, 28.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a linear pulse smoke structure that is particularly compact and suitable for driving a load with a small maximum displacement on the movable side.

[Prior art]

In general, a linear pulse motor moves a fixed distance (usually 1/4 inch for a 4-ball type) on the primary side or secondary side scale in a step-knob shape for each input pulse supplied to the primary coil. Move forward.

Along with this operation, linear pulse motors are being applied to OA equipment such as the head feed of various printers and the head feed of photoelectric reading devices that require accurate positioning control.

1. The conventional configuration of this linear pulse motor is shown in FIGS. 4 and 5. That is, Fig. 4 is a partially cutaway front view, and Fig. 5 is a partially cutaway side view.
On the next side, the two cores 2 and 3 are magnetically cut off at the center of the front, the side plates 4 and 5 that fix the cores 2 and 3 on both sides, and the backs of the cores 2 and 3 are illustrated. permanent magnets 6, 7 magnetized with the polarity of , a magnetic plate 8 joined to the back surface of the permanent magnets 6.7, and magnetic poles 2a + 2b, 3a formed on each of the iron cores 2.3.

Coils 9a, 9b, 9c, 9d added to 3b, 1 and wheels 12 to 15 rotatably supported on shafts 10.11 supported under both sides of the valley side plates 4.5. Each of the magnetic poles 2a, 2b, 3a, 3b has teeth 2al, 2bl, 3al, 3b with a 1/4 pitch shift.
l is formed. Reference numeral 16 denotes a scale forming the secondary side of the linear pulse motor, and a tooth portion 16a having the same pitch as each of the magnetic pole tooth portions 2al and the like is formed on a flat surface.

In the linear pulse motor shown in FIGS. 4 and 5, when driving, for example, by the -phase excitation method, in the process of sequentially exciting each coil 98 to 9d, each magnetic pole 2a
, 2b, 3a, and 3b Jtfiffed teeth 2al, 2bl, 3al, and 3bl sequentially face the teeth of the secondary scale, thereby moving forward by 1/4 pitch (
Although it appears to be continuous, in principle it is just a step-like displacement. At this time, the primary magnetic flux generator l
and one side of the secondary scale 16 is fixed (normal school)
The other end is movable while maintaining the load to be positioned, thereby achieving practical use.

[Problems with conventional technology]

Incidentally, in recent years, with the development of office automation equipment, various information terminal devices are becoming smaller and thinner, and this trend is also strong in floppy disk drives, for example. Under these circumstances, it is desired to realize an ultra-small and ultra-thin linear pulse motor.

Currently, the trolley type linear pulse motor shown in FIGS. 4 and 5 is not suitable for the above-mentioned market demands. That is, in the above-mentioned floppy disk drive, normally a thrust of 50 g and a stroke of about 10 to 25 degrees are sufficient, whereas it is mechanically difficult to make the body of a linear pulse motor small enough to match this thrust and stroke. To explain more specifically, there is a limit to the reduction in thickness W due to the presence of the wheel attachment mechanism, and the reduction in height H is 1
This is difficult with the conventional structure shown in FIG. 1.2, in which the opposing surfaces of the second and second teeth are perpendicular to the magnetic flux passing through the magnetic pole.

On the other hand, there is a limit to the length reduction because the magnetic poles are arranged in a straight line in the moving direction of the linear pulse motor. In other words, maximum thrust sag, maximum stroke 10~
25 BH is difficult.

[Purpose of the invention]

The purpose of this invention is to improve the configuration of the primary side of a linear pulse motor so that the driving principle is the same as the conventional one, but the size is reduced to suit low thrust and short stroke characteristics. Our goal is to provide the configuration of a pulse motor.

[Summary of the invention]

According to the present invention, this purpose is achieved by arranging four plate-shaped magnetic pole members each having a head and a leg so that the heads thereof are concentrated;
On the flat part of the head of the magnetic pole member, teeth are arranged at equal intervals in the moving direction of the linear pulse motor on the movable side, and in order of magnetic flux generation, the teeth are arranged at 1/4 pitch between the teeth and the scale teeth, which will be described later. An excitation coil is attached with a magnetic connection to each pair of magnetic pole legs located perpendicularly to the moving direction of the linear pulse motor, and the above-mentioned A permanent magnet with a different polarity for each pair of magnetic poles is arranged between each magnetic pole, and is opposed to each of the above-mentioned magnetic pole tooth portions, and the tooth portions on both sides are connected along the moving direction of the movable part with the same tooth pitch. A scale that is shifted by a pitch, and a guide means that allows the scale to be displaced within a certain range on the movable side of the linear pulse motor by having a certain gap between the teeth of the scale and the magnetic pole teeth. This is achieved by a linear pulse motor with

〔Example〕

The illustrated embodiment will be specifically described below. 1st
The figure is a perspective view showing the scale section of the linear pulse motor according to the present invention in a separated state, Figure 2 is an exploded view of the linear pulse motor shown in Figure 1 separated into each component, and Figure 3 is an exploded view of each component. It is a principle diagram showing the relative position of a magnetic pole tooth part and a scale tooth part.

In each figure, 17 to 20 are L-shaped flat magnetic poles,
Its heads 17a-20a are centrally arranged, and each leg 1
7b to 20b are arranged so as to form an H-shape as a whole. 17c to 20c are tooth parts, and each magnetic pole 17 to 20
The heads 17a to 2 (la) are formed on the same plane, respectively, and have teeth 19c, 18c, 20c, 17
In the order of c, the relative positions are sequentially shifted by 1/4 pitch with respect to the scale tooth portions to be described later. Reference numerals 21 to 24 are spacers made of a magnetic material, and are connected to the magnetic poles 17 to 20.
are joined to the bottom surfaces of the legs 17b to 20b.

Magnetic frames 25 and 26 are U-shaped in plan, and coils 27 and 28 are mounted in the center of each frame in the form of a flat plate. The magnetic frames 25 and 26 are attached to the leg portions 17b to 20b of the respective magnetic poles 17 to 20 via the spacers 21 to 24 with screws 29 to 20.
It is anchored by 32. 33 is a permanent magnet, which is magnetized as shown in the figure, and the N and S6 magnetic pole faces are each magnetic pole 19.2.
0 and the back surfaces of the heads 17a, 18a of the magnetic poles 17.18.

Reference numeral 34 denotes a backing plate, which forms a magnetic circuit on the side surface of the demagnetizing pole of the permanent magnet 33 and also functions as a fixing member on the primary side. Reference numerals 35 and 36 are guide members, respectively, a bore, a guide m, and 83. :5. 'I&i: it, 35 a 2
+36a l +36a2, and the guide member 3
5, each head 18a of the magnetic pole 18, 20 is connected to the screw 29°32.

It is fixed to the outer part of 20a. On the other hand, the guide member 36 is installed in such a way that screws 31.30 pass through the elongated holes 36bl and 36b2 formed therein, and the guide member 36 can be slightly displaced in a direction perpendicular to the moving direction of the linear pulse motor. It will be done. 37 is a leaf spring, and both ends are attached to the pin 30.3.
1 and the guide member 36 is held at the magnetic pole tooth portion 17c,
Provides restoring force in the 19c direction. Balls 38 to 41 are arranged in ball guide portions 36a2, 35a2, 36al, and 35al formed on the guide members 35 and 36, respectively. Reference numeral 42 denotes a scale forming the secondary side of the linear pulse motor, which has tooth portions 42a having the same pitch as the magnetic pole tooth portions 17c to 20c described above on the negative side, and has an angular cross-sectional cut along both sides of the end portions of the tooth portions 42a. Notches 42bl and 42b2 are formed. As shown in FIG. 3, the second tooth portion 42a includes magnetic pole tooth portions 17c on the left and right along the moving direction of the movable side.
18c.

19c, 20c (!: same pitch and 1/2 bi'7
It consists of toothed portions 42al and 42a2 having a zigzag offset. On the other hand, the notches 42bl, 42b2 engage the balls 39.41 and 38.40 to maintain a constant gear knob between the pole teeth 17c-20c and the scale teeth 42a. At the same time, the balls 39 and 41 are moved to the range of the ball guide portions 35a2 and 35al of the guide member 35, and the ball 38
, 40 are ball guide portions 36a2., 40 of the guide member 36.
Leaf spring 3 so that it can be transferred to the range of 36al
7 acts to guide the relative displacement between the scale 42 and the primary magnetic poles 17 to 20.

In the above configuration, the scale 42 side is the oJ moving side, and the magnetic poles 19 and 20 are turned into N poles by the permanent magnet 33, and the magnetic poles 17.1
8 is defined as the south pole. Now, the current element in the coil 28 is
(Tooth portion 19c of magnetic pole 19 and tooth portion 42a1 of scale 42
When the electromagnetic flux generated thereby and the magnetic flux from the permanent magnet 33 are caused to flow, the magnetic flux from the permanent magnet 33 becomes magnetic pole 1.
9 are superimposed, magnetic pole 20 is canceled, and eventually magnetic pole 19
The scale is moved to a stable point by the magnetic attraction force between the teeth 19c of the scale 42 and the teeth of the scale 42, and then stopped.

Next, at the same time as the current element ``■'' of the coil 28 is turned off, the +■
When the electromagnetic flux generated thereby and the magnetic flux from the permanent magnet 33 are superimposed at the magnetic pole 18 and canceled at the magnetic pole 17, the teeth 18c of the magnetic pole 18 A stable point is obtained by moving h 1/4 pitch by the magnetic attraction force between the tooth portion 42a2.

Next, when the current +I to the coil 27 is cut off and a current of 1 is supplied to the coil 28 at the same time, an addition/subtraction effect of the magnetic flux occurs, which is opposite to the above, and the tooth portion 2 (Ic and the scale tooth portion 42a27 of the magnetic pole 20) Then, a stable state is obtained by further displacing the 1/4 pitch scale 42.Similarly, when the current supply to the coil 28 is stopped, one current is supplied to the coil 27. The scale 42 is displaced by 1/4 pitch due to the suction force between it and the school tooth portion 42a1, and then reaches a stable state.With the above operation, the scale 42 achieves a displacement of 1 pitch, but the same By repeating the operation, the school 42 is displaced by an amount proportional to the input signal (±■).The maximum allowable displacement of the scale at this time is determined by the amount of the balls 38 to 41 that hold the gear and guide the scale 42. Transfer tolerance range, that is, each ball guide portion 3 of the guide member 35, 36
5al + 35a2, 36al, 2 of length 36a2
The stroke will be twice as long. On the other hand, when reversing the driving direction of the movable side of the linear pulse motor, the order of excitation of the excitation coils 27 and 28 may be reversed.

In the above embodiment, an embodiment in which the scale side is movable has been described, but it is also possible to make the negative side magnetic flux generating section side movable. Furthermore, instead of forming teeth in the head of each plate-shaped magnetic pole in the form of a pretext, slit-shaped teeth can be used. A pair of magnetic pole teeth facing perpendicularly to each other may integrally connect the tips of the teeth. In this case, the efficiency inevitably decreases due to the increase in leakage magnetic flux, but the mechanical strength can be increased. Furthermore, the pulse current supply to the linear pulse motor excitation coils 27 and 28 is not limited to the one-phase excitation method as in the above-mentioned embodiments, but may also employ two-phase excitation as in the conventional linear pulse motor. Then, the legs of the 1 pairs of magnetic poles are integrally formed. By making the permanent magnet 33 unidirectional, it is not necessary to provide the contact plate 34.

Moreover, the scale tooth portions 42al and 42a2 are each 1/2
In the case of a pitch-shifted implementation row, the tooth portions of a pair of magnetic pole members facing perpendicularly to the moving direction are at the same relative position, which is effective in terms of manufacturing, but this is not limited to this.
It is sufficient to have two rows of teeth with a required pitch deviation with respect to the scale 42, and the four magnetic pole teeth have a deviation of 1/4 pitch from the scale teeth in sequence. .

In addition, the mounting position of the permanent magnet 33 is not limited to the back surface of the magnetic pole, and may be provided, for example, between the end surfaces of the opposing magnetic pole teeth.

As described above, in the linear pulse motor according to the present invention, the surface of the plate-shaped magnetic pole is used as the magnetic pole surface, and these magnetic pole surfaces are arranged in a concentrated manner, and each pair is arranged along the moving direction of the linear pulse motor movable side. The magnetic poles of the magnetic poles are brought into contact with different magnetic poles of a permanent magnet, and there are two excitation coils that excite each pair of magnetic poles, and based on the interaction between the magnetic flux of the permanent magnet and the magnetic flux generated by excitation of the excitation coil, The relative position between the magnetic pole teeth and the teeth formed on the surface of the scale facing the magnetic pole teeth with the required bi-notch deviation in two rows in the direction of movement of the movable part is set by 1/4 bi-notch. It is designed to be displaced step by step. Based on this configuration, it has many features listed in the following section.

(1) Since the magnetic pole surface can be concentrated, the magnetic path length is shorter than the conventional configuration in which the magnetic poles are continuously provided along the moving direction of the movable side, and as a result, the magnetic flux efficiency is improved.

(2) Based on the fact in item (1), the secondary scale can be downsized, and accordingly, when the scale is set on the movable side, the thrust/movable side weight becomes large and responsiveness can be improved.

(3) Since the magnetic path length of the magnetic flux generated from the permanent magnet is all uniform, there is almost no variation in thrust force, and stopping accuracy is improved.

(4) The entire linear pulse motor can be made thinner and its range of application can be expanded.

That is, in relation to the items described in items (1) to (4) above, the configuration according to the present invention is not only compact, but also has excellent features such as improving the performance of linear pulse motors and having a structure suitable for mass production. This has produced a positive effect.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a separated state of the linear pulse motor 0 scale part according to the present invention, 21°t, ir-
tx Figure 1 is an exploded view of parts, Figure 3 is a principle diagram showing the tooth configuration of the magnetic pole and scale, Figures 4 and 5 are partially cutaway side views showing the configuration of a conventional linear pulse motor, respectively. It is a front view. 17-20...Magnetic poles 1, 7 c-20c...Magnetic pole teeth 25.26...Magnetic frame 27.28...Excitation fill 33...Permanent magnet 35.36...・Scale guide member 37...Plate spring 38-41...Ball 42
...Scale 42bl, 42b2...Notch 42al, 42
a2...Scale tooth part) ko1B(1(/EC)

Claims (1)

[Claims] (1) Arrange the heads of the four plate-shaped magnetic pole members having head and leg parts so that they are concentrated, and on the surface of the scale facing the plate-shaped magnetic pole members, the IJ = movable side of the apulse motor. Equally spaced tooth portions are formed in parallel with each other at a predetermined pitch along the traveling direction, and a bath is formed on the flat portion of the head of the magnetic pole member in the traveling direction of the movable side of the linear pulse motor. Therefore, teeth having the same pitch as the scale teeth are formed at equal intervals so that the relative displacement force with the opposing scale teeth changes sequentially in the order of magnetic flux generation by 17 beaches, and the movement of the linear pulse motor is An excitation coil is attached with a magnetic connection to each pair of magnetic pole legs located perpendicular to the direction of movement of the side, and a permanent magnet with a different polarity is attached to each pair of magnetic poles. disposed between the plate-shaped magnetic pole members and facing each of the magnetic pole teeth,
A scale having the same teeth and notches, and the scale,
A linear pulse smoker comprising a guide means having a certain gear/knob between the teeth and the magnetic pole teeth to allow displacement within a certain range on the movable side of the linear pulse motor.