JPS6347070B2 - - Google Patents

Description

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

Generally, a linear pulse motor moves the primary or secondary scale in steps by a fixed distance (usually 1/4 pitch for a 4-pole type motor) for each input pulse supplied to the primary coil.
Along with this operation, linear pulse motors are being applied to OA equipment such as head feed for various printers and photoelectric reading devices that require accurate positioning control. The conventional configuration of this linear pulse motor is shown in FIGS. 1 and 2. That is, Fig. 1 is a partially cutaway side view, and Fig. 2 is a partially cutaway front view. In each figure, 1 is responsible for generating magnetic flux of the linear pulse motor.
On the next side, the two cores 2 and 3 are magnetically shrunk at the center of the side surface, the side plates 4 and 5 that fix the cores 2 and 3 on both sides, and the upper surface of each of the cores 2 and 3 are Permanent magnets 6, 7 magnetized with the illustrated polarities, a magnetic plate 8 bonded to the upper surface of the permanent magnets 6, 7,
Magnetic poles 2a, 2 formed on each of the above iron cores 2, 3
Coils 9a, 9 attached to b, 3a, 3b
b, 9c, 9d, wheels 1 rotatably supported on shafts 10, 11 supported under both sides of each side plate 4, 5;
It consists of 2 to 15. And each of the above magnetic poles 2
Teeth portions 2a1, 2b1, 3a1, 3b1 are formed with a, 2b, 3a, and 3b shifted by 1/4 pitch. 16 is a scale forming the secondary side of the linear pulse motor, and the above-mentioned magnetic pole teeth 2 are shown on the top surface.
Teeth 16a are formed with the same pitch as a1.

The wheels 12 to 15 are formed integrally with rail bands 17a and 1 along both edges of the scale 16.
7b, thereby magnetic poles 2a, 2b, 3
Teeth portions 2a1, 2b1, 3a1, 3b1 of a, 3b
A constant gap g is maintained between the tooth portion 16a of the scale 16 and the tooth portion 16a of the scale 16. (Note that the gap g is exaggerated to make the diagram easier to understand).
The traveling direction of the wheels 12 to 15 is regulated by guide rails 18a and 18b fixed along the rail bands 17a and 17b.

In the linear pulse motor shown in FIGS. 1 and 2 above, when driving, for example, by a one-phase excitation method, in the process of sequentially exciting each coil 9a to 9d, each magnetic pole 2a, 2b, 3a, 3b is The formed teeth 2a ₁ , 2b ₁ , 3a ₁ , 3b ₁ step by 1/4 pitch by facing the teeth of the secondary scale in sequence (it looks continuous, but in principle it is just a step). displacement). At this time, 1
One of the next-side magnetic flux generating device 1 and the secondary-side scale 16 is fixed (normal scale), and the other is engaged with the positioning load and is movable to achieve practical use.

By the way, in recent years, with the development of office automation equipment, various information terminal devices have become smaller and thinner.
For example, this tendency is strong in floppy disk drives as well. 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. 1 and 2 is not suitable for the above-mentioned market demands. In other words, in the floppy disk drive mentioned above, the normal thrust is 50g and the stroke is
Approximately 1025 mm is sufficient, whereas it is difficult to make the linear pulse motor machine small enough to accommodate this thrust and stroke due to its mechanical structure. To explain more specifically, there is a limit to the reduction in width W due to the presence of the wheel attachment mechanism, and the reduction in height H is linear.
This is difficult with the conventional structure shown in FIGS. 1 and 2, in which the opposing surfaces of the secondary tooth portions are orthogonal to the magnetic flux passing through the magnetic poles. On the other hand, there is a limit to the shortening of the length L because the magnetic poles are arranged in a straight line in the moving direction of the linear pulse motor. That is, the maximum thrust is 50
g, it is difficult to set a maximum stroke of 10 to 25 mm.

The purpose of this invention is to improve the configuration of the primary side of the linear pulse motor so that the driving principle is the same as the conventional one, but the size can be reduced to suit the low thrust and short stroke characteristics. The purpose of the present invention is to provide a linear pulse motor configuration that can be used.
According to the present invention, this purpose is achieved by arranging the heads of four plate-shaped magnetic poles having head and leg parts so as to concentrate, and placing the movable side of the linear pulse motor on the flat part of the heads of the magnetic poles. The tooth portions are formed at equal intervals along the direction of movement of the linear pulse motor, and are sequentially displaced by 1/4 pitch in the order of magnetic flux generation, and are located on the same side with respect to the direction of movement of the movable side of the linear pulse motor. An excitation coil is attached to the legs of each pair of magnetic poles with magnetic connection, a permanent magnet having a different polarity is arranged on the back side of each pair of magnetic poles, and A scale that faces the teeth of each magnetic pole and has the same tooth pitch, and a constant gap is maintained between the teeth of the scale and the teeth of the magnetic pole so that the movable side of the linear pulse motor can move forward. This is accomplished by a linear pulse motor with directional guide means.

The illustrated embodiment will be specifically described below. FIG. 3 is a perspective view showing the scale part of the linear pulse motor according to the present invention in a separated state, and FIG. 4 is an exploded view of the linear pulse motor shown in FIG. 3 separated into each component. 5 and 6 are a plan view and a front view of the motor. In each figure, 73, 74, 75, 76 are L-shaped flat magnetic pole members, whose heads 73a, 74a, 7
5a, 76a are centrally arranged, each leg 73
b, 74b, 75b, and 76b are arranged in an H-shape as a whole. 73c, 74c, 75
c and 76c are tooth portions, respectively, for each magnetic pole member 73~
76 is formed on the flat part of the heads 73a to 76a,
The teeth 75c and 74 have the same pitch, respectively.
c, 76c, and 73c have relative positional displacements of 1/4 pitch in sequence. 21, 22, 2
3 and 24 are spacers made of magnetic material;
It is joined to the bottom surface portions of the legs 73b to 76b of the magnetic pole members 73 to 76. Magnetic frames 77 and 78 are U-shaped in plan, and coils 79 and 80 are mounted in the center of each magnetic frame in the form of a flat plate. The magnetic frames 77 and 78 are attached to the leg portions 73b to 76b of the respective magnetic pole members 73 to 76 with screws 8 via the spacers 21 to 24.
5, 86, 87, and 88. 81
is a permanent magnet, which is magnetized as shown in the figure, and the N and S magnetic pole faces are the heads 75 of the magnetic pole members 75 and 76, respectively.
a, 76a and the back surfaces of the heads 73a, 74a of the magnetic pole members 73, 74. Reference numeral 82 denotes a backing plate, which forms a magnetic circuit on the side surface of the demagnetizing pole of the permanent magnet 81 and also functions as a fixing member on the primary side.

Guide support members 83 and 84 each having an L-shaped cross section connect magnetic pole members 73 to 76 with teeth 73c to 76c in between.
76 are arranged on the heads 73a to 76a. One guide support member 83 is positioned by the above-mentioned screws 85 and 86, and the pair of magnetic pole members 7
5 and 76, the other guide support member 84 has a pair of notches 90A and 90B, as clearly shown in FIG. and the other pair of magnetic pole members 7
It can be slid on 3,74. Bis 87,
A leaf spring 89 is disposed on the guide support member 84 with both ends supported by the guide support member 88 .
4 toward the other guide support member 83.

A pair of guide members 91 and 92 having an L-shaped cross section and capable of sliding along the guide support members 83 and 84 are disposed inside the guide support members 83 and 84. A pair of notches 93a, 93b, 93c, 93d are provided in the vertical portion of each guide member 91, 92, as clearly shown in FIG.
are formed, and the two of this linear pulse motor are connected to these.
Balls 94, 95, 101, 102 for guiding both sides of the scale 72 forming the next side are rotatably received. In addition, a pair of rectangular notches 96a, 96 are provided in the horizontal portion of each guide member 91, 92.
b, 96c, and 96d are formed, and rollers 97, 98, 103, and 104 are rotatably fitted into these. As clearly shown in FIG. 6, both lower edges 72b of the scale 72
03, 104, and thereby the tooth portion 72a formed on the lower surface of the scale 72 and the magnetic pole member 7.
A constant gap g is maintained between the teeth 73c to 76c of teeth 3 to 76. Teeth 72a of scale 72
are the same pitch as the teeth 73c to 76c of the magnetic pole members 73 to 76. Ball 94, 95, 101, 1
02 is placed in a light clamped state between both sides of the scale 72 and the vertical portions of the guide support members 83 and 84 due to the biasing force of the leaf spring 89. In addition, the magnetic pole member 7
A pair of guide support members 83 on the edges of 3 to 76,
Between 84 and 84 are two pairs of stoppers 99a, 99b, 1
00a and 100b are fixed, thereby reducing the movable range of the guide members 91 and 92, and therefore the scale 72.
(However, the movable range of the guide members 91 and 92 is twice that of the guide members 91 and 92.)

In the above configuration, the scale 72 side is the movable side, and the permanent magnet 81 sets the magnetic pole members 75 and 76 as N poles and the magnetic pole members 73 and 74 as S poles.
Now, when current +I (the polarity is such that the teeth 75c of the magnetic pole member 75 and the teeth 72a of the scale 72 are attracted) flows through the coil 80, the electromagnetic flux generated thereby and the magnetic flux from the permanent magnet 81 are are superimposed on the magnetic pole member 75 and canceled on the magnetic pole member 76, and as a result, the teeth 75c of the magnetic pole member 75 overlap the scale 7.
The scale 72 is moved to a stable point by the magnetic attraction force between the two teeth 72a and stopped. Next, when the current +I of the coil 80 is cut off, the current +I of the coil 79 is turned off.
(The polarity is set such that the teeth 74c of the magnetic pole member 74 and the teeth 7a of the scale 72 attract each other). When the electromagnetic flux generated thereby and the magnetic flux from the permanent magnet 81 are superimposed in the magnetic pole member 74, This is canceled out in the magnetic pole member 73, and as a result, the tooth portion 74c of the magnetic pole member 74 moves by 1/4 pitch due to the magnetic attraction force between it and the tooth portion 72a of the scale 72 to obtain a stable point.
Next, when the current +I to the coil 79 is cut off and the current -I is supplied to the coil 80 at the same time, an addition/subtraction effect of the magnetic flux occurs which is opposite to the above, and the magnetic pole member 76
The teeth 76c of the scale and the teeth 72a of the scale attract each other, and the 1/4 pitch scale 72 is further displaced to obtain a stable state. Similarly, when the current supply to the coil 80 is stopped and a current of -I is supplied to the coil 79, the magnetic attraction force between the teeth 73c and the scale teeth 72a of the magnetic pole member 73 causes the 1/4 pitch A stable state is reached after the scale 72 is displaced.
With the above operation, the scale 72 achieves a displacement of 1 pitch, but by repeating the same operation, the scale 72 is displaced by an amount proportional to the input signal (+I). The maximum allowable displacement of the scale 72 at this time is the gap retention and the scale 72
Rollers 97, 98, 103, 10 that play a guiding role
4 and balls 94, 95, 101, 102, the allowable movement range of the guide members 91, 92, that is, the stoppers 99a, 99b, 100a, 100
The stroke has a length equivalent to twice the length between b. 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 79 and 80 may be reversed.

In this embodiment, rollers 97, 98, 1 are used to maintain the gap g between the tooth portion 72a of the scale and the tooth portions 73c to 76c of the magnetic pole members 73 to 76.
03 and 104 are used, but it is possible to replace this with a ball. Compared to this case, the contact with the ball is at a point, but the rollers 97,
There is a line contact with 98, 103, and 104. Therefore, when the same load is applied, rollers have greater durability and less wear, and can stably maintain a constant gap over a longer period of time.

Although the embodiments of the present invention have been described above, the present invention is of course not limited thereto, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiments, the scale side is movable, but the primary magnetic flux generation section side may be the movable side. Moreover, instead of forming the teeth in the concave shape on the head of each plate-shaped magnetic pole member, it is also possible to form the teeth in the form of slits. The teeth of a pair of magnetic pole members 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, linear pulse motor excitation coil 7
The pulse current supply to the motors 9 and 80 is not limited to the one-phase excitation method as in the above embodiment, but may also be two-phase excitation as in the conventional linear pulse motor.
The legs of the pair of magnetic pole members may be integrally formed. By making the permanent magnet 81 unidirectional, it is not necessary to provide the contact plate 82.

As described above, in the linear pulse motor according to the present invention, the surface of the plate-shaped magnetic pole member is used as the magnetic pole surface, and these magnetic pole surfaces are arranged in a concentrated manner so as to be arranged in a direction perpendicular to the traveling direction of the movable side of the linear pulse motor. The back surface of each pair of magnetic poles is brought into contact with a different magnetic pole of a permanent magnet, and two excitation coils are provided to excite each pair of magnetic pole members, and the magnetic flux generated by the excitation of the above-mentioned permanent magnet and the above-mentioned excitation coil is Based on the interaction between the teeth of the magnetic pole member and the scale, the relative position of the teeth of the magnetic pole member and the opposing teeth is displaced by 1/4 pitch. Based on this configuration, it has many features listed in the following section.

(1) Since the configuration allows the magnetic pole surfaces to be concentrated, the magnetic path length is shorter than in the conventional configuration in which magnetic poles are continuously provided along the moving direction of the movable side.
Magnetic flux efficiency can be improved. .

(2) Based on the fact in (1), if the secondary scale can be made smaller and the scale is made movable,
The thrust force/movable side weight is increased 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.
Stopping accuracy can be improved.

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

In other words, in relation to the items described in items (1) to (4) above, the configuration according to the present invention not only achieves miniaturization, but also improves the properties of a linear pulse motor and has a structure suitable for mass production. It has produced excellent effects.

[Brief explanation of drawings]

Figures 1 and 2 are a partially cutaway side view and front view showing the configuration of a conventional linear pulse motor, respectively, and Figure 3 is a linear pulse motor according to an embodiment of the present invention with the scale section separated. 4 is an exploded view of the parts shown in FIG. 3, FIG. 5 is a plan view of the same linear pulse motor, and FIG. 6 is a front view of the same. In the figure, 72...scale, 72a...
...Tooth portion, 73-76...Magnetic pole member, 73c-76
c...Magnetic pole tooth portion, 77, 78...Magnetic frame, 79,
80... Excitation coil, 81... Permanent magnet, 9
1, 92...Guide member, 94, 95, 101,
102... Ball, 97, 98, 103, 104
……roller.

Claims (1)

[Scope of Claims] 1. The heads of four plate-shaped magnetic poles each having a head and a leg are arranged so as to be concentrated, and the movable side of the linear pulse motor is arranged on the flat surface of the heads of the magnetic poles. The teeth are formed at equal intervals along the direction and are sequentially displaced by 1/4 pitch in the order of magnetic flux generation, and each pair is located on the same side with respect to the direction of movement of the movable side of the linear pulse motor. An excitation coil is attached to the legs of the magnetic poles with magnetic connection, and permanent magnets each having a different polarity are arranged on the back surface of each of the magnetic poles, and A scale that faces the teeth of the scale and has the same tooth pitch, and a constant gap is maintained between the teeth of the scale and the teeth of the magnetic pole to move the movable side of the linear pulse motor in the traveling direction. A linear pulse motor comprising a guide means for guiding the motor. 2. The linear pulse motor according to item 1, wherein the guide means includes a roller, thereby maintaining the constant gap.