JPS6151671A - Magnetic disc device - Google Patents

Abstract

PURPOSE:To permit wider utilization of the recording surface of a magnetic disc by forming a pulley using a pulley body and a plating layer which is made of a material permitting the welding to a steel belt provided on the external surface of this body, and welding the steel belt to the pulley. CONSTITUTION:To manufacture the pulley 10, the plating layer is formed after performing the masking required for a body member 16 which has the major diameter of 100mum smaller than the desired one. The pulley is completed by shaving its major diameter to the desired dimentions. The sheet shaped steel belt 11 of stainless steel is welded to the circumferential surface 18 of the pulley 10 by a welding part 19. Since the pulley 10 is formed by forming the plating layer 17, which is weldable to the steel belt 11, on the body member of the pulley made of aluminum alloy, the pulley 10 and the belt 11 are jointed without an extra member.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a magnetic disk device used in an external storage device of a computer.

"Prior Art and its Problems" In a general magnetic disk device, the magnetic disk is manufactured from an aluminum alloy.

For this reason, the main components of magnetic disk drives, such as the pace and carriage, as well as the pulley of the step motor that moves this carriage, are made of similar aluminum alloys, and tracking errors due to dimensional changes due to changes in ambient temperature are avoided. We are trying to resolve such inconveniences.

However, steel belts and the like for converting the rotation of the step motor into linear motion of the carriage to which the fully magnetic head is attached are made of stainless steel in terms of strength and flexibility.

However, it is difficult to weld aluminum alloy (hereinafter abbreviated as AJ gold alloy) because it forms a very brittle intermetallic compound with steel belt f: eggplant iron (FI3). Therefore, as shown in FIG. 4, positioning and locking of the steel belt 1 and the pulley 3 of the step motor 2 has conventionally been carried out by tightening a screw 5 into the pulley 3 through a reinforcing plate 4 on the steel belt 1. It is being said.

However, in this way, the steel belt 1 is inserted through the screw 5.
In the conventional locking method of locking the steel pel and the pulley 3, the reinforcing plate 4 stretched over the steel pel and the head of the screw 5 become obstacles, making it difficult to effectively utilize the outer circumference of the pulley 3. Therefore, the permissible rotation angle of the pulley 3 is narrowly limited.
As a result, the moving distance of the magnetic head is shortened, resulting in the dissatisfaction that the recording surface of the magnetic disk cannot be fully utilized.

``Means for Solving the Problems'' This invention was made in view of the above-mentioned circumstances, and it is possible to connect the step motor boob and the steel belt with five welded parts, and to connect the pulley and the steel belt for positioning. The magnetic head can be stopped smoothly, the outer circumference of the pulley can be used for a long time, the magnetic head can be moved over a longer distance, and the recording surface of the magnetic disk can be used more widely. is formed by forming a plating layer made of a material that can be welded to the bobbin main body member and the steel belt provided on the outer peripheral surface of the pulley main body member, and the steel belt is fully welded to the pulley. It is characterized by

"Example" The present invention will be described in detail below with reference to FIG.

FIG. 1 shows a main part of an embodiment of the present invention, which is a pulley to which a step motor 21C (numeral 10) is attached. A steel belt 11 is wound around this pulley IOK. As shown in FIG. 2, this steel belt 11 is latched to a carriage 14 to which a magnetic head 13 for writing and reading information to and from a magnetic disk 12 is attached, and is held by a slide bearing 15. ．．
15.

The pulley 10 of the magnetic disk device in this example is formed of a pulley body member 16 and a plating layer 17. The pulley main body member 16 is a cylindrical member having a diameter smaller than that of the pulley 10, and is made of AJ gold alloy like the magnetic disk 12. The plating layer 17 is formed on the outer peripheral surface of the pulley main body member 16, and is made of materials that can be welded to the steel belt 11, especially laser welding or electron beam welding suitable for precision welding of minute and ultra-thin parts. It is made of a material that can be joined by

Suitable materials for forming this plating layer 17 include:
Nickel (N1), chromium (Cr), or their alloys are used. These materials are also preferable in that they can be easily plated on Ag alloys by electroless plating.

Further, it is desirable that the thickness of this plating layer 17 be 50 μm or more.

If the thickness of this plating layer 17 is 50 μm or less, the plating r? The strength of pulley 117 is low, and even the Ag alloy that makes up the pulley body member 16 is melted during welding.
0 becomes uncertain.

In order to manufacture such a pulley 10, first, as shown in FIG.
As shown in →, the outer diameter of the desired pulley 1o is also 10
A pulley main body member 16 having an outer diameter smaller than 0μ1 is created. Next, after masking the side surfaces 16a, 16a of the pulley main body member 16 on which it is not necessary to form the plating layer 17, the shaft hole 161) fitted with the rotating shaft of the step motor 2, etc., as shown in FIG. 3(b). As shown in FIG. 2, the pulley body member 16 is hooked onto a jig and immersed in a plating bath to form a thick plating layer 17. Next, Figure 3 (Q)
As shown in FIG. 3, the outer periphery of the plated layer 17 is cut or ground to the desired peripheral surface 18 of the pulley 10, thereby completing the pulley 10 as shown in FIG. 3(d). Note that, in the case where the boob body member 16'jt is formed into a perfect circle, it may not be necessary to cut or grind the outer periphery of the plating layer 17.

The steel belt 11 is a thin plate made of stainless steel, and has a welded portion 19 at its longitudinal center for positioning and locking. The welded portion 19 of this steel belt 11 is plated with the above-mentioned plating r? 11
The pulley 10 is joined to the loop 18 formed by the pulley 17 in a dotted or linear manner by a welding method such as a laser welding method or an electron beam welding method.

"Function" In the magnetic disk drive configured as described above, the pulley body member 16 is plated with a material that can be welded to the steel belt 11. l17 is completely formed and boo IJ
10 is formed, the positioning and locking of the steel belt 11 wound around the pulley 10 is performed by welding the welded portion 19 of the steel belt 11 to the peripheral surface 18 of the pulley 10 formed by the plating layer 17. The reinforcing plate 4 and screws 5, which were conventionally necessary for positioning and locking the steel belt 1 and the boot U 3, are removed, and the protrusions associated with positioning and locking are eliminated from the steel belt 11. be able to. At this time, the positioning and locking of the steel belt 11 and the pulley 10 may be done by welding in a dotted manner or in a linear manner by collapsing in the axial direction of the pulley 10. Therefore, the magnetic disk device of the present invention The carriage 14 provided with the magnetic heads 13 can be moved over long distances by effectively utilizing the longer circumferential surface 18, and the recording surface of the magnetic disk 12 can be utilized more widely.

Moreover, since the plating layer F need only have a thickness necessary to position and lock the steel belt 11 by welding and joining, the ratio of the plating IVi17 to the diameter of the pulley 10 is sufficiently small. Become. Therefore, most of the pulley 10 can be formed into a υ shape by the pulley body member 16 made of the same Ag alloy as the magnetic disk, so the coefficient of linear expansion of this pulley 10 is almost the same as that of the conventional pulley 3. The difference is so small that it can be ignored. Therefore, the tracking accuracy of the magnetic disk device of the present invention can be comparable to that of conventional devices.

Furthermore, since the plating Jm17 of the pulley 10 is naturally formed in close contact with the pulley body member 16, the plating Jm17 of the pulley 10 is naturally formed in close contact with the pulley body member 16, so
When manufacturing, dimensional control regarding fitting of pulley main body member 16 and plating layer 17 can be simplified, and manufacture of pulley 10 is easy.

Incidentally, the magnetic disk device of the present invention is not limited to the above-mentioned embodiments, and includes a magnetic disk 12 made of a material that cannot be welded to a steel belt, such as plastic other than alloy 1, and a magnetic disk device made of the same material as this magnetic disk 12.
The present invention can also be applied to magnetic disk drives that are designed to eliminate tracking errors caused by temperature changes.

"Effects of the Invention" As explained above, the magnetic disk drive of the present invention is made of a material that allows for two connections between the pulley body member and the steel belt that serves as the outer peripheral surface of the pulley body member. Since the pulley is formed from the plated layer and the steel belt is welded to the pulley, the positioning and locking portion between the pulley and the steel belt is formed smoothly. Therefore, the outer periphery of the pulley can be used more effectively to move the magnetic head over a longer distance, resulting in a magnetic disk device that can more widely utilize the recording surface of the magnetic disk.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the main parts of the magnetic disk device of the present invention, Fig. 2 is a schematic configuration diagram showing the groove bottom of the magnetic disk device, and 3 (a) or φ shows a process for manufacturing a pulley. FIG. 4 is a perspective view showing the main parts of a conventional magnetic disk device. 2...Step motor, 10...Pulley, 11...Steel belt, 13...
・Magnetic head, 14... Carriage, 16...
... Pulley main body member, 17 ... Plating layer,
19...Welding part. Figure ■Figure 4

Claims (1)

[Claims] A magnetic disk drive in which a carriage to which a magnetic head is attached is moved by a steel belt wound around a pulley of a step motor, wherein the pulley is connected to a pulley body member and a pulley body member. A magnetic disk device comprising a plating layer made of a material that can be welded to the steel belt provided on the outer peripheral surface of the pulley, and the steel belt is welded to the pulley.