SE426112B - TORQUE EXTENDED DISC MAGAZINE - Google Patents

Description

7809227-7 These bending moments can cause dynamic bending of the spindle and misalignment errors. Furthermore, since there is a temperature differential between the upper and lower surfaces of the base plate, the resulting thermal expansion gives rise to static out-plane bending of the base plate.

To reduce this bending, U.S. Pat. No. 3,768,083 has proposed the use of two planes. overlying base plate sections.

One is: very rigid and supports the disc pack, the magnetic heads, the main holder and the spindle, while the other supports the powerful pole cores of the voice coil motor.

However, plane bending still occurs because the center of force of the voice coil motor and the center of gravity of both the motor and the disks are at a significant distance from the base plates neutralplazx, and distortion still occurs. due to the difference in temperature between the upper and lower surface of. basplattazi. These problems are substantially eliminated in the disc magazine of the present invention, where each speech polemotoz actuator is mounted within and supported by a hollow, generally annular. synnetic bass so. near a neutral plane as necessary, which divides the opposite walls of the base into two substantially symmetrical portions, and where the disc / spindle housing arrangement is independently attached to the base with the spindle at right angles to the neutral plane and with the center of gravity substantially coincident with this plane.

The above improved configuration has not been suggested previously in the art. U.S. Pat. No. 14,05,9090 discloses a cylindrical frame and bridge plates for centrally supporting a disk, a spindle and a motor in a symmetrical arrangement, the motor, however, consisting of a rotor surrounding a stator, furthermore only fixed heads are used, and finally, there is no voice coil motor or any equivalent movable actuator, which is mounted as described herein for controlling the heads.

A previously known disk archive has a plurality of access mechanisms, which are mounted on the outside of a cast metal casing, which surrounds the disk stack.

Here, however, the casing does not support the disc stack and the spindle, but these are supported. from the bottom. Consequently, the housing does not function as a base.

The U.S. patent 14.0O8.1 »92 describes a magnetic disk memory, in which a disk packet is enclosed in a housing. The housing has a chamber, to which air is supplied to cool the discs and to reduce the temperature gradient between the components inside the chamber. However, this arrangement does not mean a solution. the problem of dynamic out-plane bending, which is relevant in the present case. The disc magazine according to the invention practically eliminates both dynamic and static out-of-plane bending of the base.

The disc magazine according to the invention consists of a substantially symmetrical, hollow, generally annular base, which is divided into two. substantially identical portions of a neutral plane passing through opposing symmetrical walls of the base. A disc / spindle housing arrangement is inserted axially in the cavity and so on. attached to the base that the center of gravity is substantially in said plane. The arrangement supports the coil in at least one voice coil motor (VCM), the pole cores of which are moved axially relative to the coil and then attached to holders. the base within the heel joint. If two VCMs are used, they are arranged at. diametrically opposite sides of the disc. Every VCM powerhouse is so close. as: possible said plan to essentially eliminate. bend base on the base with VCM influence on the heads. The ring base configuration maintains a substantially uniform temperature differential between the inner and outer surfaces of the base. The discs are mounted with theirs. planes vertical and parallel to the neutral plane, so. that the significant temperature gradient will occur parallel to the plane of the disks.

The above and other objects, features and advantages of the invention, which are defined in the following patent claims, appear from the following, more detailed description of a preferred embodiment, which is illustrated in the accompanying drawings.

Figs. 1, 2 and 3 are schematic diagrams of a disc magazine constructed according to the principles of the prior art.

Fig. H is a schematic schematic cross-sectional illustration of a disc magazine according to the principles of the invention.

Fig. 5A and SB are a perspective illustration of the magazine according to Fig. H in disassembled condition.

DESCRIPTION OF FIGS., 1, 2 AND 3.

These figures schematically show a previously known disc magazine with an oasis plate 10, which is connected to a machine frame 11 by means of shock absorbers, shown as springs 12. At the upper surface of the base plate 10 a voice coil notch (VCM) 13 is attached. bbtom 13 consists of a voice coil 13A, which is attached to a carrier / arm arrangement lh. The arrangement lh can be moved like this. that the magnetic heads 15 are brought into the access conversion relation to a selected concentric groove on. a certain determined by a plurality of coaxially arranged magnetic disks 16.

The disc pack is rotatably mounted near one end of a spindle. The spider is supported 7809227-7. its opposite end in non-illustrated bearings supported by base plate x 10.

Then. carrier / arm arrangement marxget lh seeks out different. tracks, reaction forces F1 (rig. 2) are generated by and at VCM 13. Since the neutral axis 10a of the base plate 10 is on. a distance Y1 from the point where the force F1 is applied, the base plate is subjected to a bending moment of magnitude FY1. Other bending moments are applied to the base plate azx 10, each time it accelerates in the radial direction, on. due to the fact that the mass centers of the motor 13 and the disc / spindle arrangement 16, 1T are located above the neutral axis 10a. A force F2, which acts at a distance '12 fi from the neutral axis 10a, gives rise to a component F2Y2 on. the base plate 10. If the correct search length and the delay between searches are established. that a considerable force is applied to the VCM1S at the natural frequency of the base plate 10, in-plane bending occurs as shown in Fig. 3. This causes the carrier / arm arm assembly 114 to tilt relative to the disc 16, resulting in the out-track error between the heads lS and the discs. As pointed out above, prior art has sought to reduce this error by making the base plate 10 stiffer by increasing the thickness. However, this approach is unsatisfactory because the base plate becomes heavier and more expensive. Another problem associated with record magazines of this previously known. type is static out-plane bending due to temperature gradients between the upper and lower surfaces of the base plate 10. Increases of this kind cause thermal derailment errors. due to the uneven heating and thermal distortion of the base plate. More specifically, the spinning discs 16 and the voice coil 13 are significant sources of heat. They raise the temperature inside the panel 18 housing 18 inside the ambient air, thereby heating the upper surface of the base plate. On. Due to the extensive turbulence inside the housing, the temperature difference between two arbitrary points inside the housing is small in relation to the temperature difference: between the ambient air and the air inside the housing. The bottom surface of the base plate is normally exposed to the atmosphere or to the protection of the power supply unit, which unit is located below the plate in the machine rail ll. The resulting vertical temperature gradient across the base plate 10 causes it to bend out of the plane of the discs 16, similar to the distortion in Fig. 3, resulting in off-track errors.

The bending problems described above are substantially eliminated in the sheet gas magazine of the present invention, which will be described next. aasxæïvmmc Av nan 'rönanamwx xmrönïncsmnmn ans. h ocn s.

As shown schematically in Fig. H, the disc magazine according to the invention consists of a disc / spindle / cover arrangement 31 with a plurality of parallel discs 32 coaxially arranged in a stack 33. These discs have on their opposite planar surfaces a magnetic material, on. which digital data can be recorded on. magnetic path. The discs in the stack 33 are attached to a hub 314, which is connected to a spindle 35, which in turn is mounted in axially separated bearings 36 and driven from an external source (not shown) via a pulley 37 outside the bearings. The disk stack 33 is provided by a housing 38 which contains a plurality of circumferentially separated radially extending stiffening ribs 39.

Two sets (a, b) of magnetic heads 110 are provided, which heads read or write magnetic signs on a corresponding, axially separated group of discs 32. Each set of heads can be moved by a carrier / arm-arraxxgemmg b1, as for a selected head for conversion contact with a specific track on a particular disc 32. The arrangements 141 are preferably of the type described in the examples given above. An electrically conductive coil 142 in a corresponding linear actuator, preferably a voice coil motor (VCM) 1: 3, is connected to the end of the arrangement h1 from the heads.

Referring to Fig. 5A, each VCM 743 includes a stationary portion bra with a pair of electromagnets 15a, b arranged in peripherally separated relation to a front pole core H6 and a center pole core (not shown) formed integrally with a round rear plate. W. These pole cores are separated radially by a ring-shaped air gap (not shown). Axial movement of the corresponding coil H2, carrier / arm assembly h1 and heads 140a or b is initiated in a conventional manner by allowing current to pass through a certain selected coil.

With reference to fig. SB further contains the disc magazine with a substantially symmetrical, annular base 50. The base is preferably fully cast and consists of upper and lower cover portions Sla, b with opposite ring * or segment-shaped rounded parts. The outer ends of each rounded part end with straight sections oriented in line with each other. The straight sections on the upper part Sla are parallel to, separated from and at their outer ends connected by the straight sections on the lower part Slb. Each cane-ti Bla, b forms a pair of holders 52, 53 (of which only one set is shown).

An important feature of the invention, as shown in fig. Sa, b, is that the base 50 is divided into substantially identical halves by an imaginary neutral plane Sh, which passes vertically through the opposite walls of the upper and lower housing portions Sla, b. The disc / spindle housing arrangement 31, the carrier / / the arrangement 141 and the coils 112 in the voice coil motors 143 are moved as a unit in the direction of the spindle axis into a cavity or cavity 56, which is defined: between the upper and lower base portions S1a, b. The disc / spindle / housing arrangement 31 is then connected t. ex. with rivets directly to the hub pair 57 in the upper and lower sheath portions. 5la, b. The stationary ones. the parts. 1414 of each VCM 1: 3 is now inserted into the cavity 56 in one. direction substantially parallel to the axis of the spindle up to the corresponding spool 142, after which they are moved inwards towards the spindle axis in partially-overlying concentric relation to the respective spool and riveted at the correct holder 52 or 53. The stationary parts 1414 on. the two VCMs are then riveted directly to the holders 52, 53. The arrangement 31, 141, 142, 1414, is centered inside the cavity 56 (i.e. at equal distances from the inner walls of the housing portions 5la, b), the stationary portions 1414 being placed between the parallel straight members of the housing portions. Episode.

'Hub 57 is like that. placed axially in the base 50 that the center of gravity of the arrangement 31 including the associated structure 1ßl, 142 substantially coincides with the neutral plane. Likewise, the holders 52, 53 are arranged so that the center of gravity of the stationary part 1414 in each VCM 143 lies so. as close as possible and preferably coincides with the neutral plane 514.

It should be understood that when only one VCM has been used - or when two. VCM has been used to control heads which access different or the same disks - it is entirely possible for each VCM 143 center of power to lie in the neutral plane 514. However, if - as is the case in the illustrated embodiment - two VCM 143 have been used To control the access of different axially separated sets of heads 140a., b, it may be necessary to slightly shift the VCM power centers from the neutral plane, but in such a case the power centers should be displaced identically, the jerk small distances from the neutral plane.

The entire disc / spindle / housing arrangement must have its center of gravity located at the neutral plane of the ring base 50 to prevent inertial forces arising from the in-place acceleration of the base, generating bending moments and inducing out-plane bending modes of the type previously described. in connection with Figs. 1 ~ 3.

Since the VCM reaction forces act either -wdd or near the neutral plane 514 and the inertial forces of the disk / spindle / housing arrangement act through the neutral plane, 'dynamic cur-plane increase is substantially eliminated, static out-plane bending due to * temperature gradients also becomes substantially eliminated in the disc magazine according to the invention. It should be observed that the axis of the spindle 35 is horizontal, so. that the planes of the discs are vertical. The significant temperature gradient thus appears parallel to the plane of the disks (not "out of plane" as in the prior art embodiment according to Figs. 1-3). Since the disc / spindle / housing arrangement 31 is centered within the cavity 56 in the substantially symmetrical base 50 and the walls of the housing portions 51a, b above and below the arrangement have a uniform thickness,

Claims (7)

1. 7809227-7 there is a substantially uniform temperature differential between the cavity and the ambient air outside the base. Base 50 axial. ends are closed by casings of plastic or light metal. These covers have so. insignificant stiffness in relation to the base and the temperature gradients above them do not cause the ring base to bend out of plane. In summary, in the improved disk magazine of the present invention, the dynamic elevation of the base out of the plane of the disks caused by speech coil motor reaction forces, and the static elevation of the base out of the plane of the disks due to temperature gradients are substantially eliminated. . This eliminates an important reason for off-track errors, which: enables a reduction in the permitted track: - -to-track-distance on the respective discs. Furthermore, exchange in the field of the disc / spindle / jaw arm assembly 31 is simplified, since this. arrangements with associated variable. structure 142, 111, 140 can be removed axially as a unit after the relatively heavy stationary portions 1414 of VCM 143 have been removed by detachment in straight-off directions. A patent magazine, comprising an electromagnetically controlled impactor (143), having a fixed part (1414) and a movable part (142), which is movable parallel to and supported by an arrangement of discs (32) in a housing, characterized by a hollow bezel (50), the neutral plane (514) of which extends through the center of the base: notched upper and lower housing portions (Bla, Slb), which base is arranged to receive a disc therein for mounting / the cover arrangement (31) with its center of gravity substantially coinciding with the neutral plane, the base further being arranged for direct mounting: receiving the fixed part (1414) in the impactor (141, 142, 143, 1414), so that its center of gravity and the cancer reaction center essentially coincides with the neutral plane (514). Disc magazine according to claim 1 with at least one voice coil motor (143), characterized by means (57) for receiving the arrangement (31) in the base substantially centered inside the base cavity (56) and with the center of gravity substantially coinciding with the neutral plane and means (52). , 53) for mounting the motor core cores (146) directly in the base in such a way that the power center of each motor substantially coincides with the central plane (514). Disc magazine according to claims 1 and 2, characterized in that the means (57) receiving the disc / cover arrangement (31) place the axis of the arrangement at right angles to the plane and substantially centered in said cover portions (Bla , Slb) in the base (50) to maintain a substantially uniform temperature differential between the insides of the base. and outside. 7809227-7 h. Disc magazine according to the patent claim 3, k å. N n e t e c k n a. T thereof, a said. arrangement (31) comprises a stack (33) of magnetic disks (32), mounted with the plane of the disks vertical and parallel to the neutral plane, so. that the significant temperature gradient appears parallel to the plane of the disks. Disc magazine according to Claim 1, characterized in that it comprises 'at least' one magset head set displaceable by the actuator (143) (e.g. lma, hOb in Fig. H), which is movable in directions parallel to the neutral plume ( Sh) for conversion engagement with the disc (32), whereby the power center gets the actuator fixed. and moving part lies substantially in the neutral plane to substantially eliminate any bending moments on. the base during the parallel movement of the variable. parts. _ Disc magazine according to claim 1, characterized in that said fixed part (M4) is detachable in a direction parallel to the neutral plane, and that said. movable member (142) is then releasable together with the arrangement (31) in a direction substantially perpendicular to said plane. Disc magazine according to claim 5, comprising two actuator and two magnetic head sets, characterized in that the magnet head sets. makes access to different axially separated groups of discs, and that the center of gravity and the center of force of the respective actuators are shifted substantially identical, uwket small distances in opposite directions from the neutral plane.