GB2245408A

GB2245408A - Magnetic disk apparatus

Info

Publication number: GB2245408A
Application number: GB9112074A
Authority: GB
Inventors: Hiroshi Sakurai
Original assignee: Tokico Ltd
Current assignee: Tokico Ltd
Priority date: 1990-06-20
Filing date: 1991-06-05
Publication date: 1992-01-02
Also published as: GB9112074D0; JPH0453081A; DE4120271A1

Abstract

A magnetic disk apparatus comprises a first frame (2) having a plate portion (2A) for forming a base for a whole structure, a magnetic disk rotatably mounted on the first frame, a second frame (3) connected to the first frame having a plate portion for cove ring the first frame where the first and second frames are in abutment relation with each other to define a mounting space therebetween, an elastic member (24) arranged at said abutment surface between the first and second frames for bringing them into elastic contact with each other. <IMAGE>

Description

CES, MAGNETIC DISK APPARATUS

BACKGROUND OF THE INVENTION

The present invention relates to a magnetic disk apparatus provided with an anti-vibration countermeasure.

A magnetic disk apparatus usually comprises a housing or an outer envelope made from two-frames, i.e., a first frame which forms a base of the whole structure, and a second frame which covers the first frame. A spindle motor for rotatably holding magnetic disks, a head arm having a magnetic head at the front end thereof, a shaft for holding the head arm angularly movable thereabout and a voice coil motor for controlling the angular movement of the head arm are mounted on the first frame.

The first frame and the second frame are rigidly fixed to each other to define a tightly closed space therebetween which includes the spindle motor or other equipment described above.

However, the conventional technology has the following disadvantages. That is, since the second frame is rigidly fixed to cover the second frame, when some outer object happens to bump against the first frame, the shock produced thereby will be transmitted as vibration via the first frame to the spindle motor or the shaft etc. to cause them to vibrate. Consequently, owing to the vibration of the magnetic disks or the magnetic head, the magnetic head is dislocated from the predetermined track position, which makes impossible the magnetic disk apparatus to perform correct recording or transcription. This invention is aimed to present a magnetic disk apparatus capable of reliably preventing the disadvantages caused by vibration or shock caused 1 by bumping of the outer object to the magnetic disk apparatus.

SUMMARY OF THE INVENTION

The present invention has been made to accomplish the object mentioned above, and is directed to a magnetic disk apparatus comprising:

a first frame having a plate portion for forming a base for a whole structure; a magnetic disk rotatably mounted on said first frame; a second frame connected to said first frame having a plate portion for covering said first frame, said first and second frames being in abutment relation with each other to derine a mounting space therebetween; an elastic member arranged at said abutment surface between said first and second frames for bringing them into elastic contact with each other.

When a shock or vibration is generated by, for example, bumping of an outer object to the second frame, the shock is transmitted to the first frame. And when the shock is transmitted from the system body, it is further transmitted to the first frame via the second frame which is secured to the system body.

Then, since the first frame is supported by the second frame via an elastic member without being in direct contact with it, the shock is absorbed by the elastic member and is hardly transmitted to the first frame. Consequently, if shocks or vibrations are generated in the recording or transcription operation, they are hardly transmitted to the equipments mounted on the first frame, such as the spindle motor, the shaft etc., so that recording or transcription operation is performed without any hin- 2 1 - drance. Further, disadvantages produced by other types of vibra tions are strictly prevented. Thus, the reliability of the magnetic disk apparatus is advanced.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a plane view of a magnetic disk apparatus according to a first embodiment of the present Invention, from which second frame is omitted; Fig. apparatus Fig. apparatus Fig.

Fig.

Fig. in Fig. 5; Fig. 7 is a bottom view of the second frame shown in Fig. 5; Fig. 8 is a cross-sectional view taken along the VIII-VIII line of Fig. 7; Fig. 9 is a vertical cross-sectional view of the whole magnetic disk apparatus of the first embodiment; Fig. 10 is a left elevational view of the magnetic disk apparatus shown in Fig. 10; Fig. 11 is a plain view of a magnetic disk apparatus according to a second embodiment of the present invention, in which second frame is excluded; Fig. 12 is a cross-sectional view taken along the XII-XII of Fig.

2 is a front elevational view of the magnetic disk shown in Fig. 1; 3 is a left elevational view of the magnetic disk shown in Fig. 2; 4 is a plain view of the second frame; 5 is a front elevational view of the second frame; 6 is a left elevational view of the second frame shown Fig. 13 is a left elevational view of the magnetic disk 3 1 apparatus Fig. Fig. Fig.

shown in Fig. 12; 14 is a plain view of the second frame; is a front elevational view of the second frame; 16 is a left elevational view of the second frame shown in Fig. 15; Fig. 17 is a bottom view of the second frame shown in Fig. 15; Fig. 18 is a cross-sectional view taken along the XVIIIXVIII line of Fig. 17; Fig. 19 is a vertical cross-sectional view of the whole magnetic disk apparatus of the second embodiment; DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiment of the present invention will be described below.

In the Figs. 1 to 10, numeral 1 designates a housing comprising a first frame 2 for forming a base of the whole structure and a second frame 3 for covering the first frame 2 to define a tightly closed space therebetween, as shown more in detail in Figs. 9 and 10. The first frame 2 comprises a lower plate portion 2A, an end portion of which is formed in a half circular plate, a vertical wall portion 2B integrally formed on the other end portion of the lower plate portion 2A, and four brackets 2C integrally formed on the lower surface of the lower plate portion 2A.

The second frame 3 comprises a surrounding wall portion 3A which is in an abutment with either the outer periphery of the lower plate portion and both sides of the vertical wall portion 2B so as to define a surrounding wall around the tightly closed space, and an upper plate portion 3B integrally formed on the 4 surrounding wall portion 3A which is in an abutment with the upper surface of the vertical wall portion 2B to define said closed space above the first frame 2 in accommodation with the surrounding wall portion. Numeral 3C designates a plurality of recesses respectively formed at the corresponding position of the fixing brackets. A rubber receiving hole 3D for securing an anti-vibration rubber therein is formed at each of the recess 3C. Numeral 3E designates a plurality of threaded holes formed on the second frame 3 for securing the magnetic disk apparatus to a system body (not shown) via the second frame 3.

Numeral 4 designates the spindle motor secured to the lower plate portion 2A for rotating the magnetic disks. Numeral 5 designates two magnetic disks rotatably held by the spindle motor. These magnetic disks 5 are secured to a rotor (not shown) with a predetermined distance to each other separated by a spacer 6 through three bolts and a clamp 7.

Numeral 9 designates a shaft fixed to the lower plate portion 2A so as to be located outside of the diameter reach of the magnetic disk 5 from the rotational axis thereof. The shaft 9 is firmly held by the lower plate portion 2A for supporting the head arm (described below) angularly movable as described below.

Numeral 10 designates a head arm held by the shaft 9 angularly movable thereabout. The head arm 10 comprises a carrier portion (not shown) directly held by the shaft 9, the head holding arm portions 10A extending from the carrier portion toward the magnetic disk 5, and leaf springs 10B secured to the head holding arm portion 10A at its distal end in a manner so as to extend along the front and rear surfaces of the magnetic disk 5. At the front end of each of the leaf springs 10B, a magnetic head 11 is mounted for seeking both sides of the surfaces of the magnetic disk 5 to operate recording or transcription of information.

Numeral 12 designates said voice coil motor for controlling the angular movement of the head arm 10. The voice coil motor 12 comprises a magnet yoke 12A fixed to the first frame 3 in the vicinity of the lower plate portion 2A and equipped with a magnet (not shown), and a magnet coil 12B fixed to the head arm 10 in the vicinity of the carrier portion.

Numeral 13 designates a flexible printed circuit fixed on an upper surface of the lower plate portion 2A formed so as to be forked in two branches. One branch of the flexible printed circuit 13 extends to the spindle motor 4 and includes wirings for supplying power to the spindle motor 4. Another branch of the flexible printed circuit 13 extends to the head arm 10 and includes wirings for supplying power currency thereto. Numeral 14 designates a connecter arranged to penetrate through the vertical wall portion 2B for electrically connecting the wirings of both 1 inside and outside of the housing 1. The flexible printed circuit 13 is connected to the inside terminals of the connecter, so that it is electrically connected to the circuit plate (described below) therethrough.

Numeral 15 designates a circuit board of the disk apparatus secured to the four fixing projections 16 formed on the lower surface of the lower plate portion 2A by screw 17 respectively. This circuit board includes a connecter 18 which is connected to the above mentioned connecter 14 via a flexible printed circuit 19.

Numeral 20 designates an anti-vibration rubber installed be- 6 1 1 tween the bracket 2C of the first frame 2 and the recess 3C of the second frame 3, which is installed in the rubber receiving hole 3D. Stud bolts 21 are inserted into the anti-vibration rubber to be threaded to the thread hole 2D for elastically connecting the first frame 2 to the second frame 3.

Numeral 22 designates a first fitting groove formed on the first frame 2. The first fitting groove 22 is formed on the outer peripheral surface of the lower plate portion 2A and on the outer peripheral surface of the vertical wall portion 2B so as to extend to the upper surface thereof to form a semi-circle. Numeral 23 designates a second fitting groove formed on the inner surface of the surrounding wall portion 3A of the secona frame 3. The second fitting groove 23 is formed at the location corresponding to the first fitting groove 22 of the first frame 2 when the second frame 3 is fitted to the first frame.

Numeral 24 designates an elastic member 24 fittingly arranged between the two fitting grooves 22, 23 formed in a ring of a round cross-section. The elastic member 24 seals the gap between the first and second frames, further brings them into elastic contact to each other to prevent the transmission of vibrations therebetween.

In the magnetic disk apparatus of the present embodiment as mentioned above, the magnetic disk 5 is caused to rotate by the rotation of the spindle motor 4, and the head arm 10 is con trolled by the voice coil motor 12 to seek the surface of the magnetic disk 5 to move onto any track position for recording or transcription of information.

When a shock or a vibration is generated at the second frame 3, for example, by being dumped, the shock is transmitted to the 7 first frame 2. On the other hand, when the shock is transmitted from the direction of the system body, it is further transmitted to the first frame 2 via the second frame 3 which is secured to the system body.

However, since the first frame 2 is supported by the second frame 3 via an anti-vibration rubber 20 and an elastic member 24 so that it does not come into direct contact therewith, the shock is absorbed in the antivibration rubber 20 and the elastic member 24 and is hardly transmitted to the first frame 2. Consequently, even if shocks or vibrations are generated during the recording or transcription operations, they are hardly transmitted to the equipment mounted on the first frame 2 such as the spindle motor. the shaft etc., so that the recording or the transcription is performed without any hindrance. Further, disadvantages produced by vibrations owing to other reasons are strictly prevented.

Accordingly, the reliability of the magnetic disk apparatus is highly improved.

SECOND EMBODIMENT The second embodiment will be described with reference to the Figs. 11 to 19. Since the construction of this embodiment as a whole is almost the same as the first embodiment described above, the description of the corresponding part will be omitted and is shown on figures with the same numerals.

In the second embodiment, the circuit board is not installed in the magnetic disk apparatus but in the system body.

Numeral 31 designates the first frame comprising a lower plate portion 31A and a vertical wall portion 31B as similarly 8 constructed with the first embodiment. However, at the first frame 31 of the present embodiment, the fixing bracket 2C of the, first embodiment is not arranged. And at the corresponding location of the lower plate portion 31A, four threaded holes are formed to have a threaded inner surface and a bottom.

Numeral 32 designates the second frame of the present embodiment. The second frame 32 comprises a base plate portion 32A, a surrounding wall portion 32B opening in one direction and a covering body 32C. The second frame 32 is formed in a shape of a bag in which one end portion is open and others are closed. Recesses 33 are formed on the base plate portion 32A of the second frame 32 respectively at the locations corresponding to the threaded holes 31C of the first frame 31; and at each of the recesses 33, a hole 33A for installing an anti-vibration rubber 37 therein is formed.

On the first frame 31, a spindle motor 4, a shaft 9 and a voice coil motor 12 etc. are mounted.

A first fitting groove 34 is formed on the first frame 31 so as to extend from the outer surface of the lower plate portion 31A to the vertical wall portion 31B, and a second fitting groove 35 is formed on the inner surface of the surrounding wall portion -32B of the second frame 32. An elastic member 36 is snugly arranged between the first and the second fitting grooves 34, 35 for bringing them into elastic contact to each other.

Further, an anti-vibration rubber 37 is installed in the rubber receiving hole 33A of the second frame 32, and a stud bolt 38 is inserted through the anti-vibration rubber 37 to be threaded to the thread hole 34A so that the first frame 31 is elastically connected to the second frame 32.

9 11 By the construction mentioned above, this second embodiment of the invention can perform the same functions or provide the same effectiveness as the first embodiment previously mentioned.

In the two embodiments described above, a head arm having an arm angularly movable is employed. However, a head arm having aa arm linearly slidable is also employable which is also capable of performing the same functions or effectiveness as described above.

Further, in the two embodiments described above, the first and second fitting grooves are respectively formed on the first and second frames, and an elastic member is fittingly arra nged between them. However, since the invention is valid so long as the elastic member is located at the abutment surfaces between the first and second frames, it is permissible to form only one fitting groove on one of the first and second frames. It is also possible to form these grooves having a cross-section not of a semi-circle but of a rectangle shape.

It is also possible to form a fitting groove of a crosssection of a quarter circle to each abutment surface of the first frame and the second frame. The two quarter circles form a fitting groove of a half shape when the two frames come into contact with each other so that a "figure of eight" ring shape elastic member can be installed therein.

It is also possible to form fitting grooves on the outer surface of the first frame and the second frame so as to extend across the abutment line thereof when they come into contact to each other. Elastic members formed in a shape of a ring are arranged in the fitting groove so as to hang both the first frame and the second frame. By doing so, when the magnetic disk apparatus drops onto the floor, the elastic member will be first bumped against the floor, thus absorbing the shocks which the magnetic disk apparatus would have received.

1 1 i - il

Claims

WHAT IS CLAIMED IS: 1. A magnetic disk apparatus comprising: a first frame

having a plate portion for forming a base for a whole structure; a magnetic disk rotatably mounted on said first frame; a second frame connected to said first frame having a plate portion for covering said first frame, said first and second frames being in abutment relation with each other to define a mounting space therebetween; an elastic member arranged at said abutment surface between said first and.second frames for bringing them into elastic contact with each other. 2. A magnetic disk apparatus according to claim 1, wherein said elastic member is formed into an elongated shape, and a fitting groove for installing said elastic member therein is formed in at least one of said abutment surface of said first and second frames. 3. A magnetic disk apparatus according to claim 2, wherein a vertical wall is formed at the edge of said plate portion to define a surrounding wall around said mounting space. 4. A magnetic disk apparatus according to claim 3, wherein said vertical wall is formed on plate portions of both of said first and second frames. 5. A magnetic disk apparatus according to claims 3, wherein the inner surface of said vertical wall of one of the first and second frames is in abutment with the side surface of said plate portion of the other frame. 6. A magnetic disk apparatus according to claim 3, wherein said vertical wall is formed at the edge of said plate portion of one

12 G- of said first and second frames at opposite positions to each other with respect to said mounting space, so that said vertical wall holds said plate portion of the other frame. 7. A magnetic disk apparatus according to claim 4, wherein said fitting groove is formed continuously on an upper surface of said vertical wall and on a side surface of said plate portion. 8. A magnetic disk apparatus according to claim 1, wherein said first and second frames are connected by connecting member via said elastic member arranged between said frames in the vicinity of said elastic member. 9. A magnetic disk apparatus according to claim 1. wherein a fitting groove for installing a first elastic member therein is formed on at least one of said abutment surface, and said first and second frames are connected by connecting member via a second elastic member arranged between said frames in the vicinity of said elastic member. 10. A magnetic disk apparatus according to claim 8, wherein said connecting member is arranged on the surface of said plate portion of said first frame opposite to said mounting space. 11. A magnetic disk apparatus according to claim 9, wherein said connecting member is arranged on the surface of said plate portion of said first frame opposite to said mounting space. 12. A magnetic disk apparatus according to claim 10, wherein said connecting member is composed of a threaded members. 13. A magnetic disk apparatus according to claim 11, wherein said connecting member is composed of a threaded members. 14. A magnetic disk apparatus according to claim 1, wherein a second fitting groove is formed on the outer surface of said first and second frames so as to extend continuously on both 13 first and second frames, further comprising a second elastic member arranged in said second fitting groove, said second elas tic member being formed in an elongated shape. 15. A magnetic disk apparatus substantially as herein described with reference to and as shown un the accompanying drawings.

14 Published 1991 at 7be Patent Office, Concept House. Cardiff Road. Newport. Gwent NP9 1RH. Further copies maybe obtained from Sales Branch. Unit 6. Nine Mile Point. Cwrafelinfach. Cross Keys. Newport. NP I 7HZ. Printed by Multiplex techniques ltd. St Mary Cray, Kent.