JPS62135253A - Actuator - Google Patents

Abstract

PURPOSE:To improve the rigidity of the central frame by forming a notched portion in the middle part of the central frame and through the remaining part of this notched portion by integrating both sides of the central frame. CONSTITUTION:An actuator is composed of a coil 4 provided at an end of the arm, a side frame 7, an upper frame 8, a base frame 9, a magnet 12 and a central frame 21, where the bed is driven when the coil 4 is electrified. At this moment, in the middle part of the central frame 21 bridged over the central side of the side frame 7, notched portions 22a and 22b are formed in the longitudinal direction. Thus the flux passing through the centre of the central frame 21 is almost interrupted at the notched portions 22a and 22b, an by the remaining part 23 the rigidity of the drive motor can be improved.

Description

[Detailed description of the invention] [Industrial application field] This invention is applicable to, for example, information writing on a magnetic disk.

Regarding the actuator for driving the reading head, etc., especially the magnetic path of the actuator components! Forming drive motor: two related.

[Conventional technology]

The above-mentioned conventional actuator, as shown in FIG.
A coil 4 provided at one end of an arm 3 rotatably attached to a shaft 2 provided in the housing 1 and
A drive motor 5 is fixed to the coil 4 and forms a small magnetic path to drive the coil 4. An information writing/reading head 67a is attached to the other end of the arm 3.

The aforementioned magnetic path! As shown in Fig. 4.5, the drive motor 5 to be formed includes left and right side frames 7.7 facing each other, an upper frame 8 and a lower frame bridging the upper and lower ends of the side frames 7, 7. 9, and a middle frame 10.1 extending from approximately the center of each of the side frames in a direction perpendicular to the extension direction of the side frames and facing each other with a gap 11 in between.
0, the upper frame 8 degrees and the lower frame 9 which are perpendicular to the side frame 7.7 and each side frame 7.7, and the middle frame 10.10, which are arranged to form magnetic paths, respectively. 12.12.

The magnetic flux generated by the above permanent magnet 12.12 is expressed by the four dotted lines s shown in Figure 3: 1 m''-21J 3ez
-4, in the direction of the arrow, that is, the magnet 12 and the middle frame 10.
It crosses the gap 135', enters the middle frame 1O, proceeds in the direction of the side frame 7, forms four magnetic paths through the side frame 7χ, through the upper frame 8 and the lower frame 9, and returns to the permanent magnet. So middle frame 10.10
It has a hollow part that passes through it and is movable in the extension direction of the inner frame (2) When the coil 4 is connected to the attached coil 4, the coil 4 is driven in the direction of arrow F according to Fleming's law, and the head 6 is therefore driven. .

On the other hand, when a current is passed through the coil, the dotted line y is caused by the coil current.
-1,31-2 old middle frame 10. Side frame 7°, upper frame 8 and lower frame 9. Magnetic fluxes circulating with the side frame 7 are respectively formed. If the two inner frames 10° and 10 of ζ are not separated but are continuous as one line as shown in Figure @5, this magnetic flux will be large enough to cause magnetic saturation of the drive motor 5, increasing leakage magnetic flux and causing damage to the surrounding magnetic disks. This would affect the information recorded in the frame, increase the inductance, and worsen the response.In the past, the middle frame was spaced apart to create a gap 11 as shown in Figure 5, and the dotted line! /-1, 31-2, the total amount of magnetic flux is reduced to address the above problem.

[Problem that the invention seeks to solve]

The above problem was solved by dividing the gap 11Y setting into the middle frame Y10.10, but on the other hand, this division lowered the rigidity of the drive motor and made it easier to take pictures, 6 also vibrated, causing problems such as errors occurring when writing or reading information to the magnetic disk.

An object of the present invention is to provide an actuator that has improved rigidity while hardly reducing magnetic flux.

[Means for solving problem sounds]

In order to achieve the above-mentioned object l, the present invention forms a notch in the center portion of the inner stopper which is bridged by the substantially center side C of the side frame in a direction that longitudinally traverses the inner stopper. The left and right sides are integrated through the remaining portion of the notch.

[Effect]

Most of the magnetic flux passing through the center Y of the inner frame is cut off at the notch. The middle frame remains integral with the remainder of the notch.

〔Example〕

An embodiment of the present invention will be described below with respect to direction C:.

FIG. 1 is a front view of a drive motor according to an embodiment of the present invention, and FIG. 2 is a perspective view of a middle frame portion of another embodiment.

In these figures, 3, 7, 8, 9, 12 are all the same as 3, 7, 8, 9, 12 in FIG. So 21 is the middle frame, 22a.

22b is ζ2 on both upper and lower sides of the central part of the middle frame 21 and the middle frame?
Notches provided in the longitudinal direction, 23 are notches 2
This is the remaining part between 2a and 22b, and in this embodiment, the thickness T of this remaining part is 20% of the thickness 2t of the middle frame, that is, 0.4t.
And so.

The drive motor of this embodiment and the conventional one with the inner frame divided into two parts.
When compared with a drive motor, inductance L has a relationship between magnetic energy E and L-2]7E2 (where I = coil current), so as a result of calculating magnetic energy EY by magnetic field analysis, The ratio of the magnetic energy of the motor to the magnetic energy of the drive motor in the upper air embodiment is 1:1.
．． 08, therefore the inductance ratio is also 1:1.0
8, and there is almost no difference in inductance.

In addition, the rigidity of the a-al fixed point passing through the remaining part 23 of the drive motor can be simply considered as the total thickness of the respective thicknesses t of the upper frame 8 and lower frame 9 and the thickness of the middle frame 10 or 21. It is proportional to the cube of the size. The above a of the middle frame 10 in the conventional drive motor
-a point is shown in Figure 5 (2) (T) (There are two gaps, so the thickness there is 0, so the total thickness of the conventional drive motor is t + t - 2t, while in the actual row The thickness of the remaining part of the drive motor is 0.4t for a 20mm inner frame with a thickness of 2t.
Therefore, the total thickness is 2°4t, and the rigidity ratio of the conventional drive motor and the drive motor of the embodiment is (2t
)': (2,4t)'=1:1.7, and the rigidity of the drive motor of the embodiment is greatly improved by 70 inches.

The middle frame of another example is shown in the second piece. In the embodiment shown in FIG. 1, the notches 22a and 22b are formed on the upper surface of the inner frame 21.

Although it is provided on the lower surface, in the embodiment shown in FIG. 2, it is a notch 24a.

Provided on the front and rear surfaces of the 24bY middle frame. The drive motor of the embodiment shown in FIG. 2 also has the same effect as the g-motion motor of the embodiment of the first factor.

Although the present invention has been described with respect to an actuator for driving information writing and reading heads of magnetic disks, the actuator of the present invention can also be applied to other actuators such as optical disk devices. The remaining portion is not limited to the middle 20.

〔Effect of the invention〕

The drive motor of the actuator of the present invention has a structure in which the left and right sides of the inner frame are integrated via the remaining portion 2 of the cutout by forming a notch in the center portion of the inner frame in a direction that vertically traverses the inner frame. Since the magnetic flux passing through the central portion of the inner frame can be cut off, the rigidity of the inner frame can be greatly improved, and therefore the vibration of the actuator is reduced and the accuracy of reading etc. is improved.

44 Description of Drawings 1'I14 Vehicle The first factor is a front view of the drive motor of one embodiment of this invention, FIG. 2 is a perspective view of the inner frame portion of another embodiment, and FIG. 3 is a side view of the actuator. , FIG. 4 is a front view of the motor, and FIG. 5 is a front view of a conventional drive motor, showing the magnetic path.

4...Coil, 7.7...Side frame, 8...Upper frame, 9
...-Lower frame, 12.12... Magnet, 22a, 22b
, 24a, 24b...notch part, 23...remaining part.

Claims (1)

[Scope of Claims] Left and right side frames facing each other, upper and lower frames provided to bridge the upper and lower ends of the side frames, and a middle frame bridged approximately at the center of the side frames. a magnet that forms a magnetic path with mutually orthogonal portions of the side frames, upper and lower frames, and left and right half portions of the middle frame; In an actuator that is attached movably in an extension direction and is equipped with a coil that drives an information processing head, a notch is formed in the center of the middle frame in a direction that extends vertically through the middle frame, so that the left and right sides of the middle frame are separated. An actuator characterized in that the actuator is integrated through the remaining portion of the notch.