JPH0668198U - Magnetic disk device shield case - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a shield case of a magnetic disk device having a shielding effect against noise in a wide frequency range. [Structure] A dust-proof case 10 in which a shield case 2 having a three-layer structure of a resin sheet 3, a magnetic body 4, and a conductor 5 is formed, and functional parts such as a magnetic head of a magnetic disk device are sealed.
Further, the printed wiring board 12 on which various circuit components 12 of the magnetic disk device are mounted is wrapped around without any gap, and both ends of the shield case 2 are overlapped with each other to form an electrically closed loop having a low resistance value with a conductive tape.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a shield case for a small-sized magnetic disk device, and more particularly to a shield case for a magnetic disk device that is small and lightweight and has good shielding characteristics.

[0002]

[Prior art]

 The shield case of the conventional magnetic disk device is disclosed by the inventor of the present application in Japanese Utility Model Laid-Open No. 2-144196. FIG. 4 shows an embodiment of a shield case of a conventional magnetic disk device. In the embodiment shown in FIG. 4, functional parts such as a magnetic disk and a magnetic head, which are particularly required to be dust-proof, are hermetically sealed and housed in a dust-proof case 10 to protect them from dust, and various circuit parts that are not particularly dust-proof 11 is mounted on a printed wiring board 12 arranged outside the dust-proof case 10, and these functional components and the printed wiring board 12 are electrically connected by a flexible printed wiring board (not shown) to reduce the size and weight. A magnetic disk device designed to be realized is configured, and the shield case 17 is configured to enclose the magnetic disk device.

The dustproof case 10 has its mounting portion fixed to the support frame 13 with screws 15 via a vibration-proof suspension 14. The printed wiring board 12 is fixed to the support frame 13 with screws 16.

Since such a magnetic disk device has a structure in which the dust-proof case 10 is fixed via the vibration-proof suspension 14, the dust-proof case 10 vibrates vertically and horizontally to some extent even when an external impact is applied. In order to absorb the shock, the functional parts of the magnetic disk device housed in the dustproof case 10 are protected from vibration.

A magnetic disk device including a dust-proof case 10 containing functional parts and a printed wiring board 12 having various circuit parts 11 mounted thereon has a flexible shield attached to a support frame 13. The case 17 is entirely covered.

The shield case 17 has a flexible resin sheet 17a having a thickness of 0.1 mm to 0.3 mm coated with a conductive thin film 17b such as aluminum or copper to a thickness of 10 μm to 60 μm on one surface thereof. It is configured by forming a box-shaped or sleeve-shaped product. Further, since the shield case 17 has flexibility, the shield case 17 has flexibility, and the entire circumference of the magnetic disk device can be easily wrapped without a gap, and the magnetic disk device is shielded from electromagnetic noise. Further, the end of the conductive thin film 17b is connected to the other part of the conductive thin film 17b when the magnetic disk device is wrapped, forming an electrically closed loop.

In the magnetic disk device enclosed in the shield case 17, the support frame 13 to which the dustproof case 10 and the printed wiring board 12 are attached is attached to the metal bracket 19 made of metal through the attachment hole of the shield case 17. The magnetic disk device is fixed in the host device such as a personal computer by being fixed with the screw 18 and the bracket 19 being fixed with the mechanical chassis 21 by the screw 20. Further, since the mechanical chassis 21 is electrically grounded, the shield case 17 enclosing the magnetic disk device is also grounded via the mechanical chassis 21.

Since the shield case 17 can reliably cover the entire circumference of the magnetic disk device, the magnetic disk device is protected from electromagnetic noise. In particular, since the conductive thin film 17b of the shield case 17 is made of a shield material such as aluminum or copper, it is possible to shield against noise components in a wide frequency range. Further, since the shield case 17 is grounded via the mechanical chassis 21 of the host device such as a personal computer, the charge on the shield case 17 due to noise can be released to the ground, and the shield effect is further improved. .

As described above, the shield case 17 of the magnetic disk device has a flexible resin sheet 17a having a thickness of 0.1 mm to 0.3 mm and a conductive thin film 17b made of aluminum, copper, or the like 10 μm to 60 μm. Since it is coated in the thickness of 1 to form a box or sleeve, it can be made smaller and lighter.

FIG. 5 shows another embodiment of the shield case of the conventional magnetic disk device. In FIG. 4A, the shield case 22 is composed of a cover 23 and a base 24, and the cover 23 and the base 24 are respectively formed of a resin sheet and a conductive thin film, like the shield case 17 of FIG.

FIG. 1B shows a connecting portion between the cover 23 and the base 24, the cover 23 is composed of a resin sheet 23a and a conductive thin film 23b, and the base 24 is composed of a resin sheet 24a and a conductive thin film 24b. The contact portion is configured such that the conductive thin film 23b and the conductive thin film 24b are in contact with each other. By thus bringing the conductive thin films into contact with each other, the conductive state of the conductive thin film 17b in the case of the shield case 17 shown in FIG. 4 is improved.

[0012]

[Problems to be solved by the device]

 However, as personal computers such as notebook computers and palmtop personal computers have become smaller, miniaturization of magnetic disk devices has also been required, and the space on the host side for housing the magnetic disk devices has also become smaller. As a result, the distance from the switching power supply or DRAM, which is a noise source inside the personal computer, to the magnetic disk unit becomes shorter, and noise with a frequency of several 100 kHz from the switching power supply and noise with a frequency of several MHz from the DRAM etc. It will be easier.

Therefore, the shield case using the conductive thin film of a good conductor of aluminum or copper for the shield material of the conventional magnetic disk device is not effective in shielding the noise generated in the DRAM or the like in the frequency band of several MHz. However, there is a problem that a sufficient shielding effect cannot be obtained for noise of several 100 kHz band generated from a switching power supply or the like.

The present invention has been made to solve such a problem, and its purpose is to shield a magnetic disk device that has a sufficient shield effect against noise in a wide frequency band from several hundred kHz to several MHz. To provide the case.

[0015]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, a shield case of a magnetic disk device according to the present invention comprises a flexible metal formed of a magnetic material and a flexible metal formed of a good conductor in close contact with each other. It is characterized in that a case is composed of laminated sheets, and a connecting portion between sheets forming the case is connected by a conductive sheet to form a closed loop.

Further, the magnetic metal and the good conductor metal are characterized in that they are adhered and laminated via a conductive adhesive.

[0017]

[Action]

 A shield case of a magnetic disk device according to the present invention is formed by a sheet in which a flexible metal formed of a magnetic material and a flexible metal formed of a good conductor are closely adhered and laminated. Since the magnetic disk device is wrapped around without any gap, it is possible to shield the noise in a wide frequency band from several 100 kHz to several MHz generated by the switching power supply and DRAM of the personal computer body.

Further, since the shield case of the magnetic disk device is composed of a thin and flexible conductive thin film in which a magnetic metal and a good conductor metal are laminated, flexibility and weight reduction can be realized. it can.

[0019]

【Example】

 An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an embodiment of a shield case of a magnetic disk device according to the present invention. In FIG. 1, the shield case 2 of the shield case 1 of the magnetic disk device is composed of a resin sheet 3, a magnetic body 4, a conductor 5, and a conductor tape 6.

A dust-proof case 10 for hermetically housing functional components such as a magnetic disk and a magnetic head, various circuit components 11 constituting a magnetic disk device other than the functional components, and a printed wiring board 12 on which the various circuit components 11 are mounted. The support frame 13 that supports the dustproof case 10 and the printed wiring board 12, the vibration isolation suspension 14, the metal bracket 19, the mechanical chassis 21, and the screws 15, 16, 18, and 20 are shown in FIG. The configuration is the same as that of the above, and the description is omitted.

The shield case 2 is formed by forming a sheet having a three-layer structure of a resin sheet 3, a magnetic body 4, and a conductor 5 into a box shape, and enclosing the entire magnetic disk device without any gap, and overlapping both ends of the sheet. To configure. The both ends of the sheet are superposed on each other in the lateral direction or the longitudinal direction of the dust-proof case 10 in which the functional components of the magnetic disk device are sealed.

Since magnetic and electrical closed loops cannot be formed by simply overlapping both ends of a sheet having a three-layer structure, as an example, the inner conductors 5 of the portions where both ends of the sheet are overlapped are It can be attached with a conductor tape 6 to form a closed electrical and magnetic loop.

A dustproof case 10 for hermetically storing the functional components of the magnetic disk device is fixed to a support frame 13 together with a printed wiring board 12 on which various circuit components 11 are mounted via a suspension 14, and the whole of these components. It is covered with a shield case 2 and grounded by a mechanical chassis 21 of the personal computer body via a metal bracket 19. Therefore, the shield case 2 is also electrically grounded to the mechanical chassis 21 of the PC main body, and has the same low impedance as the mechanical chassis 21 of the PC main body, so that the shield effect is enhanced against the noise that jumps into the shield case 2. To be done.

FIG. 2 is a block diagram of the shield case of the magnetic disk device according to the present invention. FIG. 3A shows an example of the structure of the shield plate (sheet) 7 which constitutes the shield case. The shield plate (sheet) 7 is made of, for example, a resin sheet 7A made of PVC having a thickness of 200 μm, a magnetic metal 7B made of iron (Fe) having a thickness of 25 μm, and aluminum (Al) having a thickness of 20 μm. It has a three-layer structure of a good conductor metal 7C.

The magnetic metal 7B and the good conductor metal 7C are laminated by being adhered to each other via a conductive adhesive having a low resistance value, and the magnetic metal 7B and the good conductor metal 7C have a low electrical and magnetic resistance. Make the configuration to keep the value.

FIG. 2B shows the structure of the shield case 2 composed of the shield plates (sheets) 7, and FIG. 1C shows the structure of both end portions of the shield case 2 where the shield plates (sheets) 7 are superposed. . The inner conductors 5 (20 μm of Al) at the portions where both ends of the sheet are overlapped are pasted with a conductor tape 6 made of aluminum (Al). Therefore, since the shield case 2 is constructed with a low resistance value from the magnetic metal 7B to the conductive tape 7 via the good conductor metal 7C, a closed loop can be formed with a low resistance electrically or magnetically.

FIG. 3 is a magnetic shield characteristic diagram of the shield plate (sheet) according to the present invention. The shield plate (sheet) of the present invention has excellent shield (attenuation) characteristics in a wider frequency range than the conventional shield plate (PVC + Al: 20 μm).

[0028]

[Effect of device]

 As described above, the shield case of the magnetic disk device according to the present invention forms a shield case with a sheet in which a magnetic metal and a good conductor metal are closely adhered to each other, and the magnetic disk device is wrapped around without a gap. It is possible to shield the noise of a wide frequency band from several 100 kHz to several MHz generated by the switching power supply and DRAM of the main body. Further, the shield case of the magnetic disk device according to the present invention is light and excellent in flexibility.

Therefore, it is possible to provide a shield case that is suitable for a small magnetic disk device, has good shielding performance, is lightweight, and is suitable for downsizing.

[Brief description of drawings]

FIG. 1 is an embodiment of a shield case of a magnetic disk device according to the present invention.

FIG. 2 is a block diagram of a shield case of the magnetic disk device according to the present invention.

FIG. 3 is a magnetic shield characteristic diagram of a shield plate (sheet) according to the present invention.

FIG. 4 shows an embodiment of a shield case of a conventional magnetic disk device.

FIG. 5 is another embodiment of the shield case of the conventional magnetic disk device.

[Explanation of symbols]

1 ... Shield case of magnetic disk device, 2, 17, 2
2 ... Shield case, 3, 17a, 23a, 24a ... Resin sheet, 17b, 23b, 24b ... Conductive thin film, 4 ... Magnetic body, 5 ... Conductor, 6 ... Conductor tape, 7 ... Shield plate, 7A ... PVC ( 200 μm), 7B ... Fe (25 μm
m), 7C ... Al (20 μm), 10 ... dust-proof case, 1
1 ... Various circuit parts, 12 ... Printed wiring board, 13 ... Support frame, 14 ... Suspension, 15, 16, 18,
20 ... screw, 21 ... mechanical chassis,

Claims (2)

[Scope of utility model registration request] 1. A shield case for a magnetic disk device, wherein small and precise functional parts such as a magnetic head, a spindle motor and a voice coil motor are enclosed in a dust-proof case so as to enclose the entire small magnetic disk device. A case is formed by a sheet in which a flexible metal formed of a magnetic material and a flexible metal formed of a good conductor are laminated in close contact, and a connecting portion between sheets forming the case. Is a shield case of a magnetic disk device, which is connected by a conductive sheet to form a closed loop. 2. The shield case for a magnetic disk drive according to claim 1, wherein the magnetic metal and the good conductor metal are laminated in close contact with each other via a conductive adhesive.