JP3396882B2 - Recording medium drive - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin recording medium drive for driving a recording medium such as a hard disk. 2. Description of the Related Art Devices such as a personal computer such as a so-called notebook computer are increasingly required to be smaller, thinner, and larger in capacity. For this reason, there is also a strong demand for a nonvolatile auxiliary storage device attached to them to be reduced in size, thickness and capacity. [0003] A so-called flash memory is incorporated in an IC memory card thinned to a thickness of about 5 mm, but satisfactory storage capacity has not been obtained. As one means for realizing a thin, large-capacity nonvolatile auxiliary storage device, it is conceivable to use a recording medium drive device provided with a spindle motor for driving a recording medium such as a hard disk. [0005] However, in order to increase the recording capacity while reducing the size and thickness of the IC memory card to the same level,
It is necessary to prevent the spindle motor from vibrating as much as possible and realize higher rotational accuracy, thereby increasing the recording density on the recording medium. On the other hand, with the miniaturization and thinning, it has become difficult to apply, for example, an adhesive for fixing components to predetermined positions accurately and without excess or shortage.
Since manufacturing efficiency may decrease and cost may increase,
They need to be prevented. The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to reduce the thickness and size of the entire device as much as possible.
It is possible to prevent a reduction in manufacturing efficiency and an accompanying increase in cost, and also to prevent a spindle motor from vibrating as much as possible to improve rotational accuracy and increase a recording density on a recording medium to achieve a large recording capacity. It is an object of the present invention to provide a recording medium driving device capable of performing the above. In order to achieve the above object, a recording medium driving device according to the present invention is arranged such that a rotor hub for holding a recording medium is rotatably supported by a fixed portion,
It is constituted by a ferromagnetic annular thin plate, and the inner peripheral edge of the annular flat plate portion is formed in an annular projection projecting in the axial direction, and the outer peripheral edge portion of the annular flat plate portion is bent slightly inward in the axial direction. is and formed in a magnet holding portion which is folded back such Carlo Tayoku is, at its annular projection, fitted are fixed in order form an interference fit to the rotor hub, fitted into the fit shape interference fit to the magnet holding portion of the rotor yoke The held annular rotor magnet is radially opposed to the stator core supported by the fixed portion, and the annular flat plate portion of the rotor yoke is located between the stator core and the recording medium in the axial direction. I have. According to the first aspect of the present invention, the rotor magnet is internally fitted and held in the magnet holding portion of the rotor yoke formed of the ferromagnetic annular thin plate, and the gap between the stator core and the recording medium in the axial direction. Since the annular flat portion of the rotor yoke is located at the lower end, the rotor yoke prevents the magnetic flux from leaking to the recording medium while contributing to the reduction in thickness in the axial direction. The rotor yoke is fitted and fixed to the rotor hub at the annular projection in an interference-fit manner, and the rotor magnet is fitted and held in the magnet holding part in an interference-fit manner, so that the rotor yoke is fixed to the rotor hub and the rotor yoke is fixed. Is easily fixed without the need for applying an adhesive, and since the magnet holding portion is folded back, sufficient rotor magnet holding force and strength are exhibited. Embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 5 show a hard disk drive as an embodiment of the present invention. FIG. 1 is an enlarged sectional view of a main part of the hard disk drive, FIG. FIG. 4 is a plan view of a main part in a state where the stator to which the core tooth supporting annular member is fitted is attached to the base.
FIG. 5 is an enlarged cross-sectional view of a main part of a rotor yoke and a rotor magnet in a state where a stator to which a core tooth support annular member is fitted is attached to a base. Needless to say, the recording medium that can be targeted in the recording medium driving device of the present invention is not limited to a hard disk. This hard disk drive has a thickness of 5 m.
drive / read / write unit (part shown) for rotating and driving the hard disk and reading / writing from / to the hard disk, and a circuit part (not shown part) for operating them to make the same size as the IC memory card (TYPE 2) )
Are not arranged in a state of being vertically overlapped, that is, in the vertical direction as in the related art, but are arranged in a so-called horizontal direction in a substantially same plane. Reference numeral 10 denotes a 0.4 mm-thick flat plate-shaped base forged with stainless steel in a hard disk drive. Reference numeral 12 denotes a lid of the apparatus, which is made of a 0.25 mm thick stainless steel plate. The periphery of the fitting hole 10a in the base 10 is formed as an annular projection 10b projecting in the axial direction. Disc-shaped bottom 1 closing the lower end of cylindrical portion 14a
4b, a fixed shaft 14c having a columnar shape upward on the central axis.
Is fixedly protruded from the cylindrical portion 14.
The inner periphery of the base is fixed to the annular projection 10b. The upper end reduced diameter portion 14c1 of the fixed shaft 14c is
It is fitted and fixed to the lid 12. The lid 12 is supported by the fixed shaft 14 c and a synthetic resin block 15 interposed between the base 10 and the lid 12. As shown in FIGS. 2 and 4, the core tooth support ring member 16 has fitting projections 16a and 16b projecting upward in the axial direction and a remaining fitting recess 16c.
The material of the core tooth support ring member 16 is preferably a heat-resistant synthetic resin (for example, PPS with a heat-resistant temperature of 220 ° C.). The fitting protrusions 16a and 16b are provided at nine positions for each central angle of 40 degrees. Five of them are provided with fitting projections 16a projecting only upward in the axial direction, and the remaining four places are provided with upper projections 16b1 projecting upward in the axial direction, and further projecting radially inward. Expanded portion 16b2 expanded in the direction
Is provided. These two
The types of fitting projections 16a and 16b are arranged alternately except that the right fitting projection 16a on the right side in FIG. 2 is continuous. The annular bases 18a to 9 of the stator core 18
A stator coil 20 is wound around each of core teeth 18b projecting radially outward in a rotationally symmetric manner. The outer peripheral portion 18b1 of the core tooth 18b is expanded on both sides in the circumferential direction. Each fitting protrusion 16a · 1 of the core tooth support ring member 16
6b is fitted in the circumferential gap between the outer peripheral portions 18b1, and the upper surface of the fitting concave portion 16c is in contact with the bottom surface of the outer peripheral portion 18b1. Therefore, the side surface of the fitting projection 16a and the fitting projection 16
The side surface of the upper protruding portion 16b1 of b is in contact with the side surface of the outer peripheral portion 18b1. The upper surfaces of the fitting projections 16a and 16b and the outer surface 18b1 have the same height. In the case of this embodiment, the expanded portions 1 at the four fitting projections 16b are separated by a central angle of 80 or 120 degrees.
The outer peripheral surface of 6b2 is in contact with the inner peripheral surface of the portion of the outer peripheral portion 18b1 of the two adjacent core teeth 18b that is expanded in the circumferential direction. Therefore, by attaching the core tooth support ring member 16 to the stator core 18 as described above, the center alignment of the core tooth support ring member 16 and the stator core 18 is performed by itself. The flexible circuit board 22 includes an annular portion 22.
a, and a drawer 22b extending outward from one end. The outer diameter of the annular portion 22a is slightly smaller than the inner diameter of the core tooth support ring member 16, and a cutout portion 22a1 corresponding to the enlarged portion 16b2 of the fitting convex portion 16b is formed on the outer peripheral portion of the annular portion 22a. I have. When the flexible circuit board 22 is attached to the lower surface of the stator coil 20, the flexible circuit board 2
A lead portion (not shown) of the stator coil 20 is connected to a terminal region 22a2 provided on the upper surface of the second by soldering, and the cutout portion 22a1 corresponds to the enlarged portion 16b2 of the core tooth support ring member 16. Position. Thus, the core tooth supporting ring member 16
The stator core 18 to which the flexible circuit board 22 is attached is mounted on the base 10 at its annular base 18a.
The cylindrical portion 14 is in contact with the upper surface of the annular protrusion 10b.
a, and the lower surface of the core tooth support ring member 16 is partially in contact with the upper surface of the base 10 with the drawer 22b interposed therebetween. The lead portion 22b of the flexible circuit board 22 is drawn rightward in FIG. 1 along the upper surface of the substrate 10 and is connected to a circuit portion (not shown) provided on the substrate 10. The outer peripheral portion 18b1 of the core teeth 18b and the core tooth supporting ring member 16, and the annular base 1 of the stator core 18
8 a and the annular protrusion 10 b of the base 10, a filling adhesive 24 from each slot of the stator core 18.
(A material having both functions of a filler and an adhesive; preferably a thermosetting material in terms of heat resistance; for example, a material cured by heating to about 100 ° C.).
The annular projection 10b, the annular base 18a, the core teeth 18b, the core tooth support ring member 16, the stator coil 20, and the annular portion 22a of the flexible circuit board 22 are integrally fixed by solidifying the filling adhesive 24. The gap between the bottom surface of the outer peripheral portion 18b1 of the core teeth 18b and the upper surface of the fitting concave portion 16c, and the gap between the side surface of the fitting convex portion 16a or the upper protruding portion 16b1 and the side surface of the outer peripheral portion 18b1 are filled and bonded. Although it is desirable that the agent 24 enters the gap and adheres to each other and does not flow out (depending on the physical properties such as the viscosity of the filling adhesive, for example, about 0.1 mm), it is desirable that It does not matter if it is small enough not to leak. In the circumferential gap between the outer peripheral portions 18b1 of the core teeth 18b of the stator core 18 fitted and fixed to the cylindrical portion 14a of the fixed shaft member 14, the fitting projection 16a and the fitting projection 16a of the core tooth support ring member 16 are fitted. Upper projection 1 of projection 16b
6b1 is fitted, and the upper surface of the fitting recess 16c is in contact with the bottom surface of the outer peripheral portion 18b1 of the core tooth 18b.
It is possible to easily fill and solidify the filling adhesive 24 as it is in the space surrounded by the annular projection 10b, the annular base 18a, the outer peripheral portion 18b1 of the core teeth 18b, and the core tooth support ring member 16. it can. Since the base 10 is flat, unlike the case where the core tooth support ring member 16 and the like are integrally formed on the base, the amount of processing to be performed on the base is extremely small. Therefore, it can be efficiently manufactured as a whole. In addition, it is possible to use a thin plate that is difficult to process the core tooth support ring member and the like.
Since the fixed shaft member 14 having the cylindrical portion 14a is fitted and fixed to the annular projection 10b of the base 10 and the core tooth support ring member 16 is directly fixed to the base 10 and the bottom plate of the stator is omitted, so that the entire apparatus is provided. This is highly effective in reducing the thickness of the device. The annular base 18a of the stator core 18 is fitted and fixed to the annular projection 10b of the base 10, and the fitting projection 16b of the core tooth support ring member 16 is fixed in the circumferential direction between the outer peripheral portions 18b1 of the core teeth 18b of the stator core 18. Since the base 10, the stator core 18, the stator coil 20 wound around the stator core 18, and the core tooth support ring 16 are integrally fixed by the filling adhesive 24, the overall strength and The rigidity is increased, and thus the natural frequency of the entire body including the stator core 18 is increased. Since the occurrence of resonance is well prevented, vibration is effectively suppressed, which greatly contributes to the improvement of rotation accuracy, and is effective in increasing the recording density on a recording medium such as a hard disk. Further, when the core tooth supporting ring member 16 is formed of a non-metallic material as in this embodiment, unlike the case of being formed of a metal, the occurrence of eddy current loss and hysteresis loss during driving of the motor is prevented. , Good current characteristics are realized. Reference numeral 26 denotes a first ball bearing, and reference numeral 28 denotes a second ball bearing. The inner rings of the first ball bearing 26 and the second ball bearing 28 are fixed to the outer peripheral surface of the fixed shaft 14c with an adhesive. The rotor hub 30 made of aluminum (a non-ferromagnetic material) comprises a cylindrical portion 30a and an annular projecting portion 30b provided on the outer periphery of the upper portion thereof.
The outer rings of the first ball bearing 18 and the second ball bearing 20 are fixed by an adhesive. As a result, the rotor hub 30
It is rotatably supported by the fixed shaft 14c. The annular projecting portion 30b of the rotor hub 30
A 1.3 inch hard disk 31 is externally fitted to the upper cylindrical portion 30a, and the bottom surface of the inner peripheral portion of the
Ob is screwed to the annular projection 30b in contact with the upper surface of Ob. The rotor yoke 32 is made of a ferromagnetic thin plate.
The inner peripheral edge of the annular flat plate portion 32a is formed on an annular projection 32b projecting upward in the axial direction, and the outer peripheral edge of the annular flat plate portion 32a is slightly axially inward as shown in FIG. It is formed in the magnet holding part 32c bent toward the outside and turned outward. In addition, it is also possible to turn back the magnet holding part 32c inside. The rotor yoke 32 has an annular projection 32.
In (b), the outer fitting portion 30b of the rotor hub 30 is externally fitted and fixed in an interference fit. Such fixing can be realized by, for example, press-fitting the annular protrusion 30b into the inner peripheral side of the annular protrusion 32b of the rotor yoke 32. The magnet holding portion 32 of the rotor yoke 32
c, an annular rotor magnet 34 is fitted and held in an interference fit (for example, by press-fitting the rotor magnet 34 inside the magnet holding portion 32c), and is fitted to the stator core 18 radially outward. are doing. The annular flat portion 32 of the rotor yoke 32
a is located between the stator core 18 and the hard disk 31 in the axial direction. A rotor magnet 34 is fitted and held in a magnet holding portion 32c of a rotor yoke 32 made of a ferromagnetic annular thin plate, and the rotor yoke 3 is disposed between the stator core 18 and the hard disk 31 in the axial direction.
Since the two annular flat plate portions 32a are located, the rotor yoke 3
2 is a hard disk 3 which contributes to thinning in the axial direction.
1 prevents leakage of magnetic flux. The rotor yoke 32 has an annular projection 32.
2b, the rotor magnet 30 is externally fitted and fixed to the rotor hub 30 in the form of an interference fit.
Since the inner portions are fitted and held in a tight fit, the fixing of the rotor yoke 32 to the rotor hub 30 and the fixing of the rotor magnet 34 to the rotor yoke 32 can be easily performed without the need for applying an adhesive. Accordingly, a reduction in manufacturing efficiency and an accompanying increase in cost are prevented despite the extremely thin and small size. An annular seal plate 36 is fitted and fixed to the inner peripheral portion of the upper end of the cylindrical portion 30a of the rotor hub 30, and the inner peripheral portion of the seal plate 36 has a slight radial gap with the outer peripheral surface of the fixed shaft 14c. Facing each other. This prevents the lubricant fine particles and the like from the first ball bearing 26 from scattering into the disk chamber 38 from above. The cylindrical portion 30 of the rotor hub 30
a, the cylindrical portion 14a, and the rotor magnet 3
4, a labyrinth seal-like effect is obtained by the core tooth support ring member 16 and the outer peripheral portion 18b1 of the core teeth 18b of the stator core 18, and the lubricant fine particles and the like from the second ball bearing 28 are transferred between the base 10 and the magnet holding portion 32c. It can be prevented from flying into the disk chamber 38 from between. Further, the annular flat portion 32a of the rotor yoke 32 and the rotor magnet 34
The annular groove of the radially inward opening formed between
Lubricant fine particles and the like that can leak from the second ball bearing 28 can be stored, and an effect of preventing the lubricant particles from scattering into the disk chamber 38 can be exhibited. The read / write magnetic head and its driving mechanism are not shown. FIG. 6 to FIG.
FIG. 6 is an enlarged cross-sectional view of a main part of a hard disk drive as another embodiment of the present invention, FIG.
FIG. 8 is a lower perspective view thereof. This embodiment is different from the embodiment shown in FIG.
5 to 5 are the same as those in the embodiment shown in FIG. In this embodiment, the hard disk 31 is screwed by the screw 39. The screw hole 30b1 provided in the annular projecting portion 30b of the rotor hub 30 is penetrated to facilitate processing such as rust prevention and dust removal. The lower opening of the screw hole 30b1 is closed by the upper surface of the inner peripheral portion of the screw hole 30b1. For this purpose, the inner peripheral edge of the annular flat plate portion 32a is projected downward to form an annular projecting portion 32d, and the upper surface of the inner peripheral portion of the rotor yoke 32 is formed in an annular projecting portion 30b.
The annular protrusion 32d is fitted and fixed to the cylindrical portion 30a of the rotor hub 30 in an fitted state while being in contact with the lower surface of the rotor hub 30. In this embodiment, the core tooth supporting ring member 16 and the flexible circuit board 2 of the above embodiment are used.
By using the core-tooth-support-ring-unit-integrated wiring board 40 in place of 2, the number of components is reduced to increase the manufacturing efficiency. The core-tooth supporting ring unit integrated wiring board 40
It comprises an annular portion 40a and a drawer portion 40b extending outward from one end thereof. On the outer peripheral portion of the annular portion 40a, a core tooth support ring portion 42 is provided integrally over the entire periphery. The core tooth support ring portion 42 has fitting protrusions 42a and 42b projecting upward in the axial direction and a remaining fitting recess 42c. The fitting protrusion 42b includes an upper protrusion 42b1 and an expanding portion 42b2. These core tooth support ring portions 4
2, the fitting protrusions 42a and 42b, the upper protrusion 42b1, the expanding portion 42b2, and the fitting recess 42c are respectively the core tooth support ring member 42 and the fitting protrusion 42a in the above-described embodiment.
Corresponding to the upper projection 42b1, the expanded portion 42b2, and the fitting concave portion 42c, the same operation and effect can be obtained. The flexible circuit board 44 has an annular portion 44
a and a lead-out portion 44b, and are provided integrally on the upper part of the core-tooth supporting ring portion integrated wiring board 40. The annular portion 44 a is located inside the core tooth support ring portion 42 on the annular portion 40 a of the core tooth support ring portion integrated wiring board 40. 40a1 is a radial rib integrally provided on the annular portion 44a of the flexible circuit board 44.
The lead-out portion 44b extends outward from one end of the annular portion 44a, along the lead-out portion 40b of the core-tooth-support-ring-unit integrated wiring board 40, through the lower portion of the core-tooth support ring 42. An annular portion 44a of the flexible circuit board 44
Is provided with a terminal area 44a2 for connecting a lead portion of the stator coil 20 by soldering. A terminal portion 44b1 is provided on the upper surface of the leading end of the drawer portion 44b. Core tooth supporting ring unit integrated wiring board 40
The leading end of the lead-out portion 40b is connected to the terminal portion 44b.
1 is used to form a connector section 46. The core-tooth supporting ring portion integrated wiring board 40 is
For example, in the core tooth support ring portion 42, the stator core 1
8, the bottom surface of the annular portion 40a is fixed on the base 10 with an adhesive or the like. A fitting protrusion 40a2 may be provided on the bottom surface of the annular portion 40a, and the fitting protrusion 40a2 may be fitted into a fitting hole provided on the base 10 accordingly. The annular portion 4 of the lead portion 40b of the core tooth supporting ring portion integrated wiring board 40
A portion near the outer side of Oa is formed in a recess 40b1 which is one step lower than other portions, and is provided on the base 10 in order to reduce the thickness while avoiding rotation inhibition of the magnet holding portion 32c of the rotor yoke 32 and the rotor magnet 34. Through hole 10c
Is fitted to. 9 to 11 show a hard disk drive as still another embodiment of the present invention. FIG. 9 is an enlarged sectional view of a main part, FIG. 10 is a perspective view of a main part of a base, FIG. 11 is a perspective view of the stator core. This embodiment is different from the embodiment shown in FIG.
5 to 5 are the same as those in the embodiment shown in FIG. A flanged axial bearing 50b is provided at the lower end of the cylindrical radial bearing 50a.
Is fixed to the cylindrical portion 14a of the fixed shaft member 14 with its lower end surface in contact with the upper surface of the bottom portion 14b. The rotor hub 52 comprises a cylindrical portion 52a and an annular projecting portion 52b provided on the outer peripheral side. The rotor hub 52 is fitted around the bearing member 50 and is rotatably supported via a lubricant. Cylindrical part 52a of rotor hub 52
Is radially supported by the radial bearing portion 50a, and the lower annular surface of the cylindrical portion 52a is axially supported by the upper annular surface of the axial bearing portion 50b. In this embodiment, as in the embodiment shown in FIGS. 6 to 8, the annular protruding portion 52 of the rotor hub 52 is used to screw the hard disk 31 with the screw 39.
In addition, the screw holes 52b1 provided in the hole b are pierced to facilitate processing such as rust prevention and dust removal, and the lower opening of the screw holes 52b1 is closed by the upper surface of the inner peripheral portion of the rotor yoke 32. Therefore, the inner peripheral edge of the annular flat plate portion 32a is projected downward to form an annular projection 32e, and the upper surface of the inner peripheral portion of the rotor yoke 32 contacts the lower surface of the annular protrusion 52b. Are fitted to the cylindrical portion 52a of the rotor hub 52 in an interference fit. At the upper end side of the annular projection 10d of the upper projection formed on the periphery of the fitting hole 10a in the base 10, a plurality of notches 10d1 of the upper end side opening and the remaining projections 1d are provided.
0d2 is provided. The notch 10d1 of the annular projection 10d and the projection 1 are formed on the inner peripheral portion of the annular base 18a of the stator core 18.
A notch 18a1 of the radially inner opening corresponding to 0d2 and the remaining protrusion 18a2 are provided. The annular projection 10d on the base 10
The notch 10d1 of the annular projection 10d and the projection 18a2 provided on the inner peripheral portion of the stator core 18 are fitted to each other, and the projection 1
0d2 and the notch 18a1 of the stator core 18 are fitted, so that the stator core 18
Is prevented from rotating, and the protrusion 10d2 of the annular protrusion 10d is further prevented.
Is bent radially outward, whereby the stator core 18 and the annular projection 10d are fixed. Therefore, the positioning and fixing of the stator core 18 in the circumferential direction with respect to the base 10 can be performed easily and surely without the need for applying an adhesive, thereby manufacturing. In the above description of the embodiment, the vertical positional relationship, dimensions, number, material, shape,
The relative arrangement and the like are not intended to limit the scope of the present invention only to them, but are merely illustrative examples, unless otherwise specified. According to the recording medium drive of the first aspect, the rotor yoke prevents the magnetic flux from leaking to the recording medium side while contributing to the thinning in the axial direction, thereby improving the recording accuracy. The fixing of the rotor yoke to the rotor hub and the fixing of the rotor magnet to the rotor yoke are easy without the need for applying an adhesive, and the magnet holding portion is folded back. Exhibits rotor magnet holding power and strength. Therefore, even if the entire apparatus is made as thin and small as possible, it is possible to prevent a reduction in manufacturing efficiency and an accompanying increase in cost. [0060]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged sectional view of a main part of a hard disk drive. FIG. 2 is a plan view of a core tooth supporting annular member. FIG. 3 is a plan view of a main part in a state where a stator fitted with a core tooth support annular member is attached to a base. FIG. 4 is a front sectional view of a state in which a stator fitted with a core tooth support annular member is attached to a base. FIG. 5 is an enlarged sectional view of a main part of a rotor yoke and a rotor magnet. FIG. 6 is an enlarged sectional view of a main part of another hard disk drive. FIG. 7 is a plan view of the core-tooth supporting ring unit integrated wiring board. FIG. 8 is a lower perspective view of the core-tooth supporting ring unit integrated wiring board. FIG. 9 is an enlarged sectional view of a main part of still another hard disk drive. FIG. 10 is a perspective view of a main part of the base. FIG. 11 is a perspective view of a stator core. [Description of References] 10 Base 10a Fitting hole 10d Annular projection 10d1 Notch 10d2 Projection 18 Stator core 18a Annular base 18a1 Notch 18a2 Projection 30 Rotor hub 30b Annular extension 32 Rotor yoke 32a Annular flat portion 32b Annular projection 32c Magnet holder 34 Rotor magnet

Claims (1)

(57) [Claim 1] A rotor hub for holding a recording medium is rotatably supported by a fixed portion, is composed of a ferromagnetic annular thin plate, and an inner peripheral edge of the annular flat plate portion is It is formed into an annular protruding portion which protrudes in the axial direction, the outer peripheral edge of the annular flat plate portion, axially a little bent radially inward and folded magnet holding portion is formed by a Carlo Tayoku is At the annular projection, an annular rotor magnet which is fitted and fixed to the rotor hub in an interference fit, and which is fitted and held in the magnet holding portion of the rotor yoke in an interference fit, is supported by the fixed portion.
Phase against the the stator core and radially recording medium driving apparatus characterized by annular flat plate portion of the rotor yoke is located between the stator core and the recording medium in the axial direction.