JPS6043062A - Linear actuator - Google Patents

Abstract

PURPOSE:To increase the effective stroke range capable of obtaining necessary thrust by sequentially reducing a magnetic flux distribution by a permanent magnet toward the boundary of the respective poles, thereby equalizing the thrust generated at a movable coil. CONSTITUTION:Plate-shaped permanent magnets 12, 12 are respectively secured to the upper and lower inside faces of a box-shaped yoke 11. The magnets 12, 12 are arranged at the upper and lower positions as a pair in a facing state at the vertexes of triangles. A gap 13 of the prescribed width is formed between the upper and lower magnets 12 and 12, and a square-shaped movable coil 14 of plane shape is arranged longitudinally movable in the gap 13. The magnetic flux distribution by the magnets 12, 12 is sequentially reduced toward the boundary of the respective poles.

Description

[Detailed description of the invention]

The present invention relates to a linear actuator that can be used, for example, as a device for transporting a recording/reading head to a predetermined track in a floppy disk device. Conventionally, a well-known type of linear actuator is the voice coil type shown in the first illustration. That is, the cylindrical hole 2 formed by the yoke IK
A cylindrical permanent magnet 3 is fitted on the inner peripheral surface of the permanent magnet 3, and a coil 4 wound around a movable element 5 is fitted into the inner part of the permanent magnet 3 for movement in the axial direction. It is being subordinate
・Since the coil 4 is located within the value flux formed by the permanent magnet and the yaw, by correcting the coil 4, the movable element 5 receives a thrust in the direction of the barb 1 of the coil 4.
With the second thrust, it is possible to transport, for example, an old C record or STI record to a predetermined track on a floppy disk. However, in the case of the upper Mt::voice coil type linear linear actuator, the IC must have a magnetic path sufficient to pass the magnetic flux inside the coil in the circle f, 54. -Lokotoha Tatsu: 1 [deru,
Ru. In addition, since there is a Yoder part inside the fill, when the inductance becomes large, there are 159 points. In order to solve the problems of the voice coil type linear actuator mentioned above, a flat type linear actuator as shown in Figure 22) has also been proposed.
Ru. In Figures Z to Fang 4, plate-shaped permanent magnets 7 and 7 are respectively fixed to the subsurface A eye 11 of the matching yoke 6. A gap 8 of a predetermined width is formed between the valley magnets 7 and 7, and a rectangularly wound 109i
Move to coil 9 or yoke 6's eldest child's 1st direction! 2). Each permanent magnet 7.7 has a thickness J of N and S poles.
However, in the longitudinal direction, there are 4I (') in the opposite direction, and the upper and lower magnets are different from each other (the comrades are facing each other). The coil 9 is arranged so that it is slightly longer than ~7/7 of the length of the magnet 7, as shown in Figure 4. When the coil 9 is in the wave zone, a thrust is generated in the same direction on both sides of the coil 0. However, due to the actuator of this type, tt + upper, P of 1 elevation I coil 9, middle 1 □ 6j of the moving direction as shown in Fig. 5 and the daytime and line width of the coil)
If the dimensions are larger than 111, thrust can be obtained, and a large tr.
i, ``l', r-> 5° Also, the maximum (multiple II stroke) of the V fill coil 9 (in the S movement direction of the coil 9 as shown in Figures 3 and 4) Pak 1 on the inside dimension
4) I can only move the length that corresponds to the length, and the movement stroke is too short.Moreover, as shown in Figure 5 -
(Yes, the coil position example 1- Thrust distribution &"l
：The force changes in an ill-like manner and is not constant, and the necessary 411 force is obtained by the actuator. It's limited. Objectives of the present invention (-1, In a flat linear actuator, the thrust force generated within the stroke is 'y;: -j〆iI To provide a linear actuator having the following structure.The feature of the present invention is to provide a linear actuator in which an 11th-stage coil is arranged in a plane on a permanent magnet, and an upper 8-pin permanent [4 stones 1 each with 419' poles] is provided. At the same time, the E7.
In the C filter linear actuator,
-11. Refer to the figure 1i%i L to explain the wooden hammer light.
There are plate-shaped permanent magnets 12 on the upper and lower inner 11111 surfaces, respectively.
．． 12 is fixed, but this permanent magnet 12, j2 is the same as the permanent magnet 7 in the conventional example shown in Figures 2 to 'A-4.
．． 7 and fart l, ``A'' point (・j-1 is located at the point where the apex points of the triangle are butted against each other as -λ・J, which are arranged one above the other. -1-Lower magnet 12. A gap 13 of a predetermined width is formed between the yoke 12, and within the gap J3, an ijJ'ldr coil 14 wound so as to have a four-degree rectangular planar shape extends in the longitudinal direction of the yoke 1. III!lj1'' Noh.Each Mizuku magnet 7: ]I 2 ii-N pole and S-pole are magnetized in the thickness direction (・Roga,'' 2 parts and rJ
・The magnets 12 and IZ placed at the bottom are triangular shapes that are aligned with each other.
Ka-handling g y・Surname to be reversed r:, middle, upper and lower a1
(1111! It is cut so that the comrade faces x), jj;E. In detail, each permanent magnet 1z is The magnets 11 are arranged alternately in the direction of movement of the coils 14, and are magnetized perpendicularly to the direction of movement of the coil 14 in the z direction. , each ii': 7W decreases as the IQ boundary is reached. In addition, 7μ of the upper part and F part
Stone 12.12-1, make this separately and study hard.
i'fi K- Both sides, +;'i may be made to meet at the end, but in short, it is sufficient to make the width narrower as it approaches the center of one movement direction, and the pair of magnets should be integrated from the beginning. It may also be expressed in the form 1iv. Now, as shown in Figure t7, coil J4 is moved! One limit of the T111 range is 1 to 'Lfi VC, and in the state where the VC is facing one of the 5 poles, the coil 14 is suitably connected to the wide part of the magnetic wire and the opposite coil].
One side of side A of 1 is used to generate a thrust to the left in the figure, and the other mmB part of the coil 14 facing the narrow part of the insulator is used to generate a thrust to the right in the figure. I-, the mmB part of the coil 14 and the opposing 1-romagnet (10mm)
Because the surface of the tG ratio, X1II, which faces part A on one side of the Kari-C coil 14 is different from the other, there is a difference in the thrust generated on both sides, and as a result, the coil 14 generates a thrust to the left in the figure. - will move it to the left. In this way, when the mmB section of the coil 14 is placed in a position opposite to the magnetic hook of -+tlll to the left, the thrust generated at the -;))B section of the coil 14 also becomes a leftward Jjr force. However, in this case, since the area of the magnetic pole facing part A on one side of the coil is reduced, the overall thrust 1t:] does not change much. Autopsy: 1 ton of fruit shown in Figure 8! i! χ represents the distribution of magnetic flux in the above-mentioned sister 11 of the present invention, and
It can be seen that by setting the i-kei to 7 cedar full-width characters, it changes linearly and relatively gently in proportion to the change in i-11'. On the other hand, in the magnetic flux distribution in the conventional flat linear actuator shown by broken line Y, there is relatively little change in magnetic flux within the same magnetic pole, and at the boundary between each magnetic pole. It can be clearly seen that the irB flux distribution is changing. In addition, Figure 9 shows the magnetic flux component I1] (
This shows the change in thrust based on A, and Plan J! F
X represents the actual sister example of the present invention, and broken line y-1 represents the conventional example. As is clear from these curves, according to the conventional i <: 11 Vc, the maximum force is 11 (the force is large or the thrust is also 11). K 'M'J L,, Although the maximum thrust is relatively small according to the present invention, the required I
It can be seen that the effective stroke, which is the range in which the fli force can be expressed as A, is large, and that the thrust force is approximately constant within the A/α curve of this effective stroke. Furthermore, in a triangular permanent magnet, the center of the magnetic field will be shifted toward the wider part of the magnet than the simple dimensional center, so if we look at a pair of magnets with alternating magnetic poles, each magnet
% center or outside (shifting towards the till, the distance between the magnetic clamping center and the center is 1.

[It's thicker, so the coil 14's S le 11
Stoyoke is a wide-ranging man, and it's 21.
In the conventional one described in Fig. 2 to Fig. 4, the maximum displacement is 4 out of 4.
However, according to the embodiment of the present invention, when the winding width of the coil is made smaller, the effective stroke becomes larger than the conventional one. The effect 1 of the above-mentioned fruit Q 13'll of the present invention is to transfer the magnetic flux of the 41μ group of a pair of permanent magnets S to the 2'7 oy b into a magnetic (, needle) As the boundary is reached, the lJ moving coil is arranged in this magnetic flux (r), so it is not necessarily necessary to make the permanent IA stone triangular, but it can be made magnetic by other + stages. However, if the magnetic flux is made to decrease sequentially as it reaches the σp boundary, the effect of the seagull can be obtained.The values of the present invention can be used for the figures JO1 and JO11. This shows the real sister mode of the permanent magnet, for example, a pair of N-S rectangular main jifts has a commutative pole 17, which has the opposite polarity to the sovereign, at the boundary of the main jift of the N-S pair.
]・For example, in Figure 11, the main 1i+9 of the N -S pair
．． Mainly at the boundary of 2tJ (competent poles 21, 2 with opposite polarity
At the same time, the commutative poles 21 and 22 are arranged in a triangular shape so that each of their cutting points are inserted into each of the main poles 19 and 20, and the bases of the triangles of the commutative poles 21 and 22 correspond to each other. It is made by joining the same sides. If the permanent magnet is formed as shown in Figure U and Figure 1, the boundary of the main pole (= the point near J
The bundle is slightly stepped and the fourth order 11. # Slightly, υ′ becomes negative 5)・i+i of the fi magnetic flux as shown by the solid line (4) It is possible to take a large coil as shown in Figure 12. b) The coil must be made into a rectangular shape. As shown, the coil 23(1) directly contributes to thrust generation.
) - side C' between the side A part and the other side B part, bend the part I) inward and move it in the jbb direction 11
．． By forming 11 oblique sides, this length may also be made to contribute to the thrust force. The inward penetration dimension of each side C,]), the moving direction jli, and the opposing angle m
'4 "If you change it appropriately, everyone will get 4L=
＠-ru]f "Can change force, has ℃, 4f
It is possible to produce a uniform blur with very little force (1'-). In each of the examples above, the 11-IIJ+ coil was connected to an air-core coil, but if a magnetic material is provided inside the coil, even greater thrust can be obtained. In addition, there is no need to use two stones, just one. A coil may be placed in the magnetic flux between the permanent <a stone and the H-ri. In the flat type linear actuator with tC filters facing each other, the magnetic flux distribution due to the permanent magnet is made to decrease each (11) lθζ as it reaches the boundary of Chapter 1, so 1''゛!help The thrust force generated by the cocoil becomes uniform, and it becomes possible to enlarge the effective stroke range in which the necessary thrust force can be obtained.

[Brief explanation of drawings]

Figure 1 is a sectional view showing an example of a conventional linear actuator, Figure 2 is an imr diagram showing another example of a conventional linear actuator, and Figure 3 is a permanent magnet of the same type. Only the part shown is 1-Slope 1], Fig. 4 is a 31/- side view of the permanent straight stone part, and Fig. 5 is the same 1-Conventional Ita 11 (. Diagram showing 9 genders,
”・Figure 6 I1 Partially broken slope view showing an example of the present invention,
Figures 1 and 7 are the permanent magnet part ρ flat ii diagram of the same example as above, Figure 8 Figure 6 *: 1 in the above example and the conventional example
)F, the line 1n] which accepts the bundle distribution in layer 9 is upper 1i11
An actual sister example of the present invention (and an I-diagram showing the gravity of the thrust in the conventional 911). 1-1 is a top view, i'++1 is also a part of the permanent magnet!;) is a top view showing other aspects of the actual gun, and 121-1 can be used in the present invention. FIG. 7 is a plan view showing another embodiment of the +jJ moving coil. 11... Yoke, 1z... Permanent magnet, 14... Moving coil, pole, 21, 2z... Compensating pole, 23... Moving coil.

Claims (1)

[Claims] A planar movable coil is placed face-to-face with the permanent magnet, and each magnetic core of the permanent magnet is distributed alternately in the direction of movement, and the permanent magnet is magnetized in a direction perpendicular to the direction of movement of the magnetic coil. 1. A linear actuator comprising: a linear actuator, characterized in that the magnetic flux distribution of the permanent magnet is sequentially reduced as it approaches a boundary between each magnetic pole;