JP2007053900A - Motor for magnetic disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor for magnetic disk drive adapted to achieve thinning of a motor through a simple and inexpensive configuration. <P>SOLUTION: In an inner-roller motor, a magnetic seal plate 33 is provided between an area where a magnetic disk 13 of a rotor 9 is placed and a winding 23. The outer peripheral edge of the magnetic shielding plate 33 is situated radially inward from an outer peripheral edge of a core back of a stator core 21. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor used for driving a magnetic disk such as a hard disk drive.

  In recent years, information recording apparatuses such as hard disk drives have been rapidly reduced in size and thickness. A conventional motor used for driving a hard disk is configured to have a thickness of about 5 mm or less as shown in FIG. That is, as shown in FIG. 7, in the motor 51, a shaft 55 is screwed to the center of an aluminum fixing member 53 composed of, for example, a plate-like base portion 53a and a peripheral wall portion 53b, and a magnetic disk ( A rotor 59 on which 57 (corresponding to a hard disk) is mounted is rotatably fitted via two ball bearings 61. Further, the stator 65 is fitted in the peripheral wall portion 53 b of the fixing member 53, the driving rotor magnet 63 is fitted on the outer peripheral portion of the rotor 59, and the stator 65 is spaced from the rotor magnet 63 in the radial direction by a predetermined interval. Are arranged opposite to each other. Thus, a motor in which the rotor magnet rotates inward in the radial direction with respect to the stator may be referred to as an inner rotor type motor.

  The rotor 59 is made of a magnetic material (for example, SF20T), and a thin flange portion 59a that covers the upper portion of the rotor magnet 63 is formed on the outer peripheral surface thereof, and the flange portion 59a is positioned above the flange portion 59a. The magnetic flux from the rotor magnet 63 is prevented from leaking with respect to the magnetic disk 57. At the same time, leakage of the magnetic flux is also prevented by increasing the magnetic resistance due to the gap 60 between the flange 59a and the upper end surface of the rotor magnet 63.

  The stator 65 includes a stator core 67 composed of an annular portion and a plurality of magnetic poles projecting radially inward from the inner peripheral surface, and a winding 69 is wound around each magnetic pole of the stator core 67.

  Here, an insulating resin cover 75 is disposed on the upper surface of the stator core 67, and this resin cover 75 forms an annular shape that is substantially the same type as the annular portion of the stator core 67. A plurality of engaging portions 75a projecting radially outward at predetermined intervals are formed, and a plurality of protrusions 77 hanging down toward the stator core 67 are formed on the lower surface of the resin cover 75 in the circumferential direction. It is provided at equal intervals. In the resin cover 75, each protrusion 77 is fitted in the through hole 79 of the stator core 67, and windings passing between the magnetic poles (hereinafter referred to as “crossover wires”) pass through the upper surface of the resin cover 75. The resin cover 75 is pressed against the stator core 67 and fixed. Further, the above-described crossover wire 71 passes through the upper surface side of the resin cover 75 and is locked to the locking portion 75a. As a result, the crossover wire 71 moves inward of the stator core 67 and the winding 69 is loosened. This prevents the magnetic pole from being hindered. Thus, the resin cover 75 is a member provided to lock the crossover wire 71.

  Further, an annular first magnetic shield plate 81 fitted in the upper end portion of the peripheral wall portion 53b of the fixing member 53 is disposed above the stator 65. The first magnetic shield plate 81 allows the magnetic disk to be moved from the stator 65 to the magnetic disk. Magnetic flux leakage to the 57 side is prevented. The first magnetic shield plate 81 includes a first plate-like member 81a made of a magnetic material, and an insulating film 81c bonded to a surface facing the stator 65 with an adhesive 81b. Thus, the first plate-like member By attaching the insulating film 81c to the member 81a, the winding 69 of the stator 65 and the first plate-like member 81a are electrically insulated.

  Furthermore, a through-hole 53c having an L-shaped cross section is formed in the base 53a of the fixing member 53, and a flexible circuit in which one end of a lead wire 83 drawn out from the winding 69 of the stator 65 is provided inside the through-hole 53c. They are electrically connected by a soldering portion 87 of a substrate (FPC) 85. The FPC 85 is connected to a control circuit (not shown) provided outside the motor 51 and directly below the fixing member 53, and the rotation of the motor 51 is controlled by this control circuit. The FPC 85 is provided with a pressure contact type connector (not shown) for electrical connection with the control circuit.

  Here, since the fixing member 53 is made of aluminum which is a nonmagnetic material, the magnetic flux from the stator 65 may adversely affect the control circuit. Therefore, a second magnetic shield plate 89 that prevents magnetic flux from leaking from the stator 65 is attached to the lower surface of the base portion 53 a of the fixing member 53. The second magnetic shield plate 89 includes an insulating film 89a attached to the lower surface of the base 53a of the fixing member 53, and a second plate member 89c made of a magnetic material adhered to the lower surface of the insulating film 89a with an adhesive 89b. The lead wire 83 and the soldering portion 87 from the winding 69 are electrically insulated from the second plate member 89c by the insulating film 89a. Further, in the second magnetic shield plate 89, the portion facing the connector of the FPC 85 is notched, and there is no problem in connection with the control circuit. In FIG. 7, the first magnetic shield plate 81 and the second magnetic shield plate 89 are shown with an enlarged thickness in order to clarify the configuration.

JP 2000-253632 A

  Incidentally, since the first plate member 81a and the insulating film 81c are bonded to each other by the adhesive 81b in the first magnetic shield plate 81, the thickness of the first magnetic shield plate 81 is increased and the motor 51 is made thinner. It was a factor that hinders. Therefore, it has been proposed to make the motor 51 thin by making the insulating film 81c as thin as possible. However, in this case, the insulating film 81c becomes too thin, and thus it is difficult to attach, so that it is insulated from the first plate member 81a. Adhesion with the film 81c is very troublesome and causes a new problem of increasing the manufacturing cost.

  Similarly, since the second magnetic shield plate 89 is also configured to adhere the second plate-like member 89c and the insulating film 89a with the adhesive 89b, the second magnetic shield plate 89 becomes thicker. It was a factor that hindered thinning.

  The resin cover 75 disposed on the upper surface of the stator 65 is attached to the stator core 67 with a projection 77 fitted into the through-hole 79, and is locked to the locking portion 75a through the upper surface side. However, since the resin cover 75 may not be completely tightly fixed to the stator core 67, the resin cover 75 remains attached to the stator core 67 in an unstable state. It may have become.

  As a result, as shown in FIG. 8, since the resin cover 75 partially lifts from the upper surface of the stator core 67 and comes into contact with the first magnetic shield plate 81, the first magnetic shield plate 81 is hindered. The shield plate 81 must be attached upward to some extent. This increases the thickness from the fixing member 53 to the first magnetic shield plate 81, and as a result, prevents the motor 51 from being thinned. Here, it is conceivable that the resin cover 75 is completely tightly fixed to the stator core 67 with an adhesive. However, the resin cover 75 is not fixed horizontally due to uneven application of the adhesive, or the adhesive is not fixed to the stator core 67. The stator 65 flows between the fixing member 53 and the stator 65 is displaced, or the fixing state of the stator 65 is deteriorated due to the pressure accompanying the hardening of the adhesive, and further, outgas is generated from the adhesive, and the adhesive. There is a possibility that various problems such as an uncured problem and an increase in assembly man-hours may occur.

  By the way, as one method for reducing the thickness of the motor 51, it is conceivable to thin the rotor 59, and accordingly, it is necessary to further reduce the thickness of the flange portion 59a. However, since the rotor 59 is machined, it is difficult to reduce the thickness of the flange 59a below the current level while maintaining the processing accuracy of the flange 59a. This also reduces the thickness of the motor 51. It was a hindrance.

  Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to make it possible to reduce the thickness of a motor with a simple and inexpensive configuration.

In claim 1 of the present invention, a rotor having an annular rotor magnet and a portion on which a magnetic disk is placed on the outer periphery, and a rotor supported rotatably about a central axis;
A stator core having a plurality of magnetic poles arranged radially toward the center axis and an annular core back connecting the radially outer ends of the plurality of magnetic poles, and a winding wound around each of the plurality of magnetic poles A stator having a wire and facing the rotor magnet;
A magnetic shield plate in which the axial position is between the portion where the magnetic disk is placed and the winding, and the outer peripheral edge is located radially inward from the outer peripheral edge of the core back;
It is provided with.

  A second aspect of the present invention is characterized in that the outer peripheral edge of the shield plate is located radially inward from a portion where a part of the winding straddling between the magnetic poles is locked between the adjacent magnetic poles.

  According to a third aspect of the present invention, a winding locking member is disposed on one side in the axial direction of the stator core, and the winding locking member locks a part of the winding straddling between adjacent magnetic poles. A stop portion is provided, and the outer peripheral edge of the shield plate is located radially inward from the locking portion.

  The rotor magnet is configured to rotate radially inward with respect to the stator, and such a motor may be referred to as an inner rotor type motor. Further, the stator in this inner rotor type motor is usually used to prevent windings passing between the magnetic poles (hereinafter referred to as “crossover wires”) from passing through the core back in the radial direction and becoming complicated. Is provided with means for locking the connecting wire to the core back (corresponding to a winding locking member in the present invention).

According to a fourth aspect of the present invention, the winding locking member further includes an annular portion disposed on one side in the axial direction of the core back, and a convex guide extending radially inward from the inner peripheral surface of the annular portion. Part
The magnetic shield plate is characterized in that its outer peripheral edge is positioned in the radial direction by contacting the inner peripheral part of the guide part.

  A fifth aspect of the present invention is characterized in that the magnetic shield plate is fixed to a portion of the winding facing the magnetic shield plate in the axial direction by an adhesive.

  A sixth aspect of the present invention is characterized in that the inner peripheral edge of the magnetic shield plate is located radially outward from the tip of the magnetic pole.

  In the embodiment of the present invention, the portion protruding from the through hole in the protrusion is melted and locked to the core back, so that stress that deforms the peripheral portion of the through hole does not act. In particular, the magnetic disk drive motor is particularly effective when configured as described above when the rigidity around the through hole is low in order to reduce the thickness. For example, if the protrusion of the winding locking member is made of metal and inserted into the through hole, and the tip is plastically deformed, the stator core will be deformed by the load stress applied during the plastic deformation. If it is a structure, there is no deformation. A preferable material for the winding locking member is a synthetic resin such as PBT (polybutylene terephthalate).

  In the present invention, it is possible to reduce the thickness of the magnetic disk drive motor.

  An embodiment of a magnetic disk drive motor according to the present invention will be described with reference to FIGS. However, this embodiment is an example when applied to a thin motor having a thickness of several millimeters used to drive a magnetic disk of a hard disk drive device. FIG. 1 is a partial sectional view, and FIG. 1 is a cross-sectional view taken along line AA, and FIG. 3 is a view for explaining assembly of the motor.

  As shown in FIG. 1, the motor 1 according to this embodiment includes a fixed member 3 such as an aluminum chassis having a plate-like base portion 3 a and a peripheral wall portion 3 b, and a shaft screwed into the center of the fixed member 3. 5, a rotor 9 that is rotatably fitted to the shaft 5 via two ball bearings 7, and a stator 11 that is disposed opposite to the outer side of the rotor 9 in the radial direction at a predetermined interval. Has been. Thus, a motor configured such that a rotor magnet 18 (described later) is positioned radially inward with respect to the stator 11 may be referred to as an inner rotor type motor.

  The rotor 9 has a magnetic disk 13 mounted thereon, and an annular magnetic plate 17 described later is fitted on the outer peripheral surface of the rotor 9 with an adhesive. The rotor 9 has a cylindrical shape and a rotor main body portion 9a in which the ball bearing 7 is fitted on the inner peripheral surface, and a large diameter portion 9b formed on the outer periphery of the lower portion of the rotor main body portion 9a. The flange 9c is formed on the upper outer periphery of the large diameter portion 9b. The small flange 9d protrudes from the lower outer periphery of the flange 9c to a larger diameter than the flange 9c. ing. The magnetic disk 13 is placed on the upper surface of the large-diameter portion 9b and is pressed and fixed by fixing means (not shown) attached to the rotor main body portion 9a. An annular motor driving rotor magnet 18 is fitted on the outer peripheral surface of the large-diameter portion 9b so as to contact the lower surfaces of the flange portion 9c and the small flange portion 9d. The outer diameter of the rotor magnet 18 is larger than that of the small flange portion 9d, and the upper surface of the rotor magnet 18 is exposed to the magnetic disk 13 side accordingly.

  On the outer peripheral surface of the flange portion 9c, a magnetic plate 17 is fitted and fixed with an adhesive interposed, and is placed on the upper surface of the small flange portion 9d. The outer diameter of the magnetic plate 17 is larger than the outer diameter of the rotor magnet 18 and covers the upper surface of the rotor magnet 18. Further, a predetermined gap 19 is formed between the magnetic plate 17 and the rotor magnet 18 by the small flange portion 9d, and a predetermined gap is also formed between the magnetic plate 17 and the magnetic disk 13. The magnetic plate 17 and the magnetic disk 13 are prevented from contacting each other.

  Here, the magnetic plate 17 is preferably formed of a magnetic material having a low magnetic permeability such as SUS430, for example, so that the magnetic flux from the rotor magnet 18 (Nd—Fe—B magnet in this embodiment) is magnetic. Leakage to the disk 13 side can be prevented, and effects such as loss of data recorded on the magnetic disk 13 and malfunction during data writing or reading can be prevented. Further, the gap 19 formed between the rotor magnet 18 and the magnetic plate 17 reduces the magnetic flux from the rotor magnet 18 toward the magnetic disk 13, while increasing the magnetic flux acting on the stator 11. The rotor 9 can be efficiently driven to rotate. Note that the rotor 9 is preferably formed of free-cutting steel such as SF20T having high machinability. By doing so, the rotor 9 requiring high dimensional accuracy can be formed with high accuracy.

  The stator 11 is fitted into the inner periphery of the peripheral wall portion 3b of the fixing member 3, and as shown in FIG. 2, the stator 11 is projected inward in the radial direction from the annular portion (core back) 21a and the annular portion 21a. The stator core 21 is composed of a plurality of magnetic poles (teeth) 21b and windings 23 wound around the magnetic poles 21b. Note that there are various methods for winding the winding wire 23 depending on the desired rotation characteristics, and this embodiment only shows an example. As is apparent from FIG. 2, the stator 11 in the inner rotor type motor shown in this embodiment normally has a winding 27 (crossover wire) passing between the magnetic poles 21b passing radially inward from the annular portion 21a. In order to prevent the wearing from becoming complicated, it is necessary to have a configuration in which the connecting wire 27 is locked to the annular portion 21a. Therefore, in this embodiment, a means for locking the crossover wire 27 to a resin cover 29 described later is provided.

  As shown in FIG. 2, an insulating resin cover 29 that is an annularly formed winding locking member is disposed on the upper surface of the stator core 21. The resin cover 29 is provided with an annular portion 29d placed on the upper surface of the annular portion 21a of the stator core 21 and a radially outward projection from the upper side of the outer peripheral surface of the annular portion 29d with a predetermined interval in the circumferential direction. A plurality of locking portions 29a, a plurality of protrusions 31 projecting in the axial direction from the lower surface of the annular portion 29d toward the stator core 21, and provided at predetermined intervals in the circumferential direction, and an inner peripheral surface of the annular portion 29d A plurality of guide portions 29b protruding inward in the radial direction and provided at a predetermined interval in the circumferential direction, and protruding outward in the radial direction from the lower side of the outer peripheral surface of the annular portion 29d and provided at a predetermined interval in the peripheral direction. And a plurality of projecting portions 29c.

  Here, when the connecting wire 27 is wound around the other magnetic pole 21b from the magnetic pole 21b through the upper surface of the annular portion 29d, the connecting wire 27 is again connected to the upper surface of the annular portion 29d via the lower surface of the locking portion 29a. It is locked so that it is guided to the lower surface of the stator core 21. The guide portion 29b is used for positioning a first magnetic shield plate 33 described later.

  In the present embodiment, as shown in FIG. 2, the above-described connecting wire 27 is stretched from the upper surface side of the resin cover 29 to the lower side of the engaging portion 29a, and the connecting wire 27 is engaged with the engaging portion 29a. Thereby, the inward movement of the connecting wire 27 of the stator core 21 is prevented. On the other hand, as shown in FIG. 1, the protrusion 31 of the resin cover 29 is fitted into each of the plurality of through holes 21 c formed in the axial direction in the annular portion 21 a of the stator core 21, and the tip of the protrusion 31 is the stator core. The resin cover 29 is firmly fixed to the stator core 21. The resin cover 29 is firmly fixed to the stator core 21. Here, the protrusion 31 is formed integrally with the resin cover 29, but may be formed of a separate member. In addition, since the through hole 21c of the stator core 21 is formed at the position farthest from the magnetic pole 21b between the adjacent magnetic poles 21b, the magnetic characteristics of the stator core 21 are hardly affected.

An annular first magnetic shield plate 33 is disposed on the upper surface of the stator 11, and the first magnetic shield plate 33 is a first plate member made of a magnetic material having a low magnetic permeability such as SUS430. 33a and an insulating resin 33b coated on the lower surface of the first plate-like member 33a with a predetermined thickness. The lower surface of the first magnetic shield plate 33 is PSA (Pressure
Sensitive
It is fixed to the upper surface of the stator 11 by an adhesive 35 such as Adhesive, and the outer periphery of the first magnetic shield plate 33 is disposed in contact with the guide portion 29b of the resin cover 29 and positioned in the radial direction. At this time, the windings 23 of the stator 11 and the first plate member 33a are electrically insulated from each other by the resin 33b coated on the first plate member 33a. As the insulating resin coated on the first plate-like member 33a, for example, an epoxy resin, a polyester resin, a PES resin, or an acrylic resin can be used.

  Further, a through hole 3c having an L-shaped cross section is formed in the base portion 3a of the fixing member 3, and the flexible circuit board (FPC) 37 disposed in the through hole 3c is pulled out from the winding 23. The lead wires 39 are electrically connected by the soldering portion 41. The FPC 37 is connected to a control circuit (not shown) disposed outside the motor and directly below the fixing member 3, and drive control of the motor 1 is performed by this control circuit. The FPC 37 is provided with a pressure contact type connector (not shown) for electrical connection with the control circuit.

  Here, for example, if the fixing member 3 is made of a nonmagnetic material such as aluminum, the magnetic flux from the stator 11 may adversely affect the control circuit described above. A second magnetic shield plate 43 for preventing the magnetic flux from leaking from the stator 11 is fixed (not shown). The second magnetic shield plate 43 includes, for example, a second plate member 43a made of a magnetic material with low permeability such as SUS430, and an insulating resin coated on the upper surface of the second plate member 43a with a predetermined thickness. The lead wire 39 and the soldering part 41 connected to the FPC 37 and the second plate member 43a are electrically insulated by the insulating resin 43b. Further, in the second magnetic shield plate 43, the portion facing the connector of the FPC 37 is cut away, and there is no problem in connection with the control circuit. Here, as the resin 43b coated on the second plate-like member 43a, the same material as that used for coating the first magnetic shield plate 33 can be used. In FIG. 1, the first magnetic shield plate 33 and the second magnetic shield plate 43 are shown enlarged in thickness in order to clarify the configuration. In the motor 1 configured as described above, a drive current is supplied to the winding 23 of the stator 11 to excite the stator core 21, and the rotor 9 is rotationally driven by the mutual magnetic action between the stator core 21 and the rotor magnet 18. Then, the magnetic disk 13 placed on the rotor 9 rotates integrally with the rotor 9, and the data recorded on the magnetic disk 13 is read or read by the read / write head (not shown). Is written.

  Next, the assembly procedure of the motor 1 will be briefly described with reference to FIG. First, as shown in FIG. 3, a stator assembly 45 in which the stator 11 is attached to the fixed member 3 is assembled, and a rotor assembly 47 including the shaft 5, the pair of ball bearings 7, the rotor 9, and the rotor magnet 18 is assembled. Keep it. Before the rotor assembly 47 is attached to the stator assembly 45, a cylindrical member 49 for aligning the axial centers of the rotor assembly 47 and the stator 11 is installed on the fixed member 3 inside the stator 11. deep. At this time, the outer peripheral surface of the cylindrical member 49 is substantially in contact with the inner peripheral surface of the stator 11, and the thickness of the cylindrical member 49 is substantially equal to the gap between the stator 11 and the rotor magnet 18. It has become. In this state, after inserting the rotor assembly 47 along the inner peripheral surface of the cylindrical member 49, the shaft 5 is screwed to the fixing member 3. Thereby, the rotor assembly 47 can be fixed to the stator assembly 45 in a state where the axes of the rotor assembly 47 and the stator 11 are exactly aligned. Thereafter, the cylindrical member 49 is removed, and the magnetic plate 17 is attached to the rotor 9. At this time, since the magnetic plate 17 is attached by adhesion, no load is applied to the ball bearing 7. As an assembling procedure, it is possible to attach the stator 11 after the rotor assembly 47 is first attached to the fixing member 3 and installed on the cylindrical member 49. Any of the above assembling methods can be realized by configuring the magnetic plate 17 as a separate member from the rotor 9.

  Therefore, according to the above-described embodiment, the first magnetic shield plate 33 and the second magnetic shield plate 43 are made of insulating resin 33b, 43b on one surface of the first and second plate-like members 33a, 43a, respectively. Therefore, both the magnetic shield plates 33 and 43 can be formed thinner than in the case where the insulating film is bonded with an adhesive as in the prior art, and the time required for bonding is also increased. As a result, the entire motor 1 can be thinned. In addition, according to the coating, since the resin film thickness can be set in detail, various insulating films can be formed according to the application, and the adhesive that has been used conventionally becomes unnecessary, Accordingly, the manufacturing cost can be reduced.

  In particular, since the second magnetic shield plate 43 can be formed thin, it is not necessary to greatly reduce the thickness of the fixing member 3 when the motor 1 is thinned, so that the rigidity of the motor 1 can be prevented from being lowered.

  At this time, insulating resins 33b and 43b may be coated on both the front and back surfaces of the plate-like members 33a and 43a of the magnetic shield plates 33 and 43. By doing this, outgas from the plate-like members 33a and 43a is performed. Since the generation of rust can be prevented and surface treatment such as rust prevention treatment is not required, the manufacturing cost can be reduced. Here, if the plate-like members 33a and 43a are formed of a material that does not generate outgas, as shown in FIG. 1, it is possible to outgas even by coating the resin 33b and 43b only on one surface of the plate-like members 33a and 43a. Can be prevented.

  In addition, by fixing the first magnetic shield plate 33 to the upper surface of the winding 23, the first magnetic shield plate 33 is disposed in a space formed between the stator 11 and the magnetic disk 13. The leakage of magnetic flux from the stator 11 can be prevented without increasing the thickness of the motor. At this time, since the guide portion 29b of the resin cover 29 facilitates the alignment of the first magnetic shield plate 33 in the radial direction, the first magnetic shield plate 33 can be accurately fixed at a predetermined position. .

  By the way, in the above-described embodiment, the first and second magnetic shield plates 33 and 43 are bonded to the stator 11 or the fixing member 3 with an adhesive such as PSA. It doesn't matter.

  In the embodiment described above, the first magnetic shield plate 33 is directly bonded to the upper surface of the stator 11 with the adhesive 35, but the outer periphery of the first magnetic shield plate 33 is connected to the peripheral wall portion of the fixing member 3. The first magnetic shield plate 33 is disposed at a predetermined interval above the stator 11 by being fixed to the upper end of 3b or fixed to the upper surface of the resin cover 29. Of course, the upper part of the stator 11 may be covered to prevent leakage of magnetic flux from the stator 11.

  Furthermore, according to the above-described embodiment, each protrusion 31 provided on the resin cover 29 is fitted into the through hole 21c of the stator core 21, and the tip of each protrusion 31 is led out to the lower surface side of the stator core 21. Since the tip is deformed by melting and locked to the periphery of the through hole 21c, the resin cover 29 can be firmly fixed to the stator core 21. Therefore, the peripheral edge of the resin cover 29 does not lift from the upper surface of the stator core 21 as in the conventional case, and the increase in the thickness of the stator 11 due to the lift of the resin cover 29 can be prevented, and the motor 1 can be made thinner. it can.

  The insulating resin cover 29 is locked to the stator core 21 at the periphery of the through hole 21c by deforming the tip (lower end) of the protrusion 31 by melting. It is particularly effective. In other words, for example, when a protrusion is formed by rivets and crimping is performed to crush the tip of the protrusion, the rigidity of the stator cannot be maintained with respect to the load applied to the stator at the time of crushing, which may cause damage. On the other hand, by deforming the tip of the projection 31 by melting and engaging the periphery of the through hole 21c, such a load does not act on the stator 11 at all, and the rigidity of the motor can be maintained.

  In the above-described embodiment, the resin cover 29 is fixed to the stator core 21 by melting and deforming the tip of the protruding portion 31. However, the resin cover 29 is fixed to the stator 11 without applying a load. As a method, for example, as shown in FIG. 4, the protrusion 31 of the resin cover 29 may be composed of a pair of claw-shaped portions 31 a having protrusions at the tips and spaced apart from each other. The pair of claw-shaped portions 31a have a maximum width set larger than the inner diameter of the through hole 21c, and when inserted from one side of the through hole 21c, the protrusions come into contact with the peripheral edge of the through hole 21c and It is pressed in the approaching direction and elastically deformed, and insertion of the through hole 21c is allowed. And if the front-end | tip of the nail | claw-shaped part 31a protrudes from the other side of the through-hole 21c, while the pressure-contact force to the nail | claw-shaped part 31a will lose | disappear, the shape will be restored, and the nail | claw-shaped part 31a will be in the periphery of the other side of the through-hole 21c. The protrusions are locked, and movement relative to the through hole 21c is restricted. In this way, the resin cover 29 can be fixed to the stator core 21 more easily. Here, the nail | claw-shaped part 31a comprises the elastic latching | locking part of this invention.

  Furthermore, according to the above-described embodiment, the thin flange 59a for preventing magnetic flux leakage that has been conventionally formed integrally with the rotor 59 (see FIG. 7) is configured as a separate member by the magnetic plate 17, Magnetic plate 17 prevents leakage of magnetic flux from rotor magnet 18 to magnetic disk 13 side. This eliminates the need for precision machining of the thin flange 59a as a conventional means for preventing magnetic flux leakage that has hindered the rotor from being thinned. As a result, the rotor 9 can be thinned easily and accurately. Thus, the motor 1 can be thinned.

  In addition, in the conventional case, since the flange portion 59a is formed integrally with the rotor 59, it is difficult to select a material that has two properties of high machinability and low magnetic permeability required for the rotor. However, as in the above-described embodiment, by configuring the conventional rotor 59 with the two members 9 and 17, a material with high machinability such as free-cutting steel (for example, SF20T) is selected for the rotor 9. As a result, the processing accuracy of the rotor 9 can be drastically improved, and magnetic flux leakage from the rotor magnet 18 to the magnetic disk 13 can be prevented by selecting a material having a low magnetic permeability for the magnetic plate 17. That is, since it can be composed of a material according to the characteristics of each part, the high-performance rotor 9 can be formed compared to the conventional structure.

  Further, instead of the magnetic plate 17 attached to the rotor 9, the first magnetic shield plate 33 may be extended to the rotor 9 side so as to cover the upper surface of the rotor magnet 18. Even in this case, the magnetic fluxes of the rotor magnet 18 and the stator 11 can be prevented from leaking to the magnetic disk 13 side as in the above-described embodiment. On the contrary, instead of the first magnetic shield plate 33, the upper surface of the stator 11 may be covered with the magnetic plate 17.

  In the embodiment described above, the rotor 9 is made of free-cutting steel. However, the material of the rotor 9 is not particularly limited to this, and focusing on the thermal expansion characteristics, for example, heat such as aluminum. A material having a high expansion coefficient may be used. In this way, the aluminum expands at a high temperature, so that the generation of a gap due to the thermal expansion of the ball bearing 7 can be suppressed, and the rotation characteristics of the ball bearing 7 at a high temperature can be prevented from being deteriorated. In this case, since aluminum is a nonmagnetic material, a magnetic member as a yoke is preferably interposed between the rotor magnet 18 and the rotor 9. For example, a cylindrical magnetic member may be newly added, or the inner peripheral wall portion 17a is formed on the inner peripheral surface of the magnetic plate 17 so as to have an L-shaped cross section, and the inner peripheral wall portion 17a It may be arranged between the inner peripheral surface of the rotor magnet 18 and the rotor 9. In this case, as shown in FIG. 5A, the magnetic plate 17 may be configured such that a gap 19 is formed between the rotor magnet 18 and the magnetic plate 17, or as shown in FIG. As shown, the magnetic plate 17 may be configured not to form a gap. Note that the materials of the rotor 9 and the magnetic plate 17 are not necessarily different materials as described above, and may be made of the same kind of material.

  Furthermore, in the above-described embodiment, the magnetic plate 17 is externally fitted by being fixed to the rotor 9, but the attachment of the magnetic plate 17 is not limited to this method. For example, FIG. 1), the gap 19 between the magnetic plate 17 and the rotor magnet 18 is eliminated by omitting the small flange portion 9d in FIG. 1, and the magnetic plate 17 is directly placed on the rotor magnet 18 by the magnetic force of the rotor magnet 18. As shown in FIG. 6B, a protrusion 45 for caulking and fixing is formed on the upper surface of the small flange portion 9d, and the magnetic plate 17 is fixed to the rotor 9 by caulking the protrusion 45. Alternatively, although not shown, it may be fixed by press-fitting.

  Furthermore, in the above-described embodiment, the magnetic plate 17 is formed of a member different from the rotor 9, so that the assembly accuracy of the motor 1 is improved, and the axes of the stator 11 and the rotor magnet 18 are particularly easily aligned. Rotational characteristics can be achieved.

  In the above-described embodiment, the thin motor 1 including the first magnetic shield plate 33, the second magnetic shield plate 43, the magnetic plate 17, and the resin cover 29 locked to the stator 11 is illustrated. However, it is not always necessary to include all of the first magnetic shield plate 33, the second magnetic shield plate 43, the magnetic plate 17, and the resin cover 29. To obtain a thin motor, What is necessary is just to provide at least any one.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.

  As described above, since the insulating film of the first magnetic shield plate disposed between the stator and the magnetic disk disk is formed by coating, the insulating film is bonded to the conventional adhesive film. The first magnetic shield plate can be reduced in thickness so that the entire motor can be reduced in thickness, and a thin motor having a good magnetic shield effect can be provided.

  In addition, since an insulating film is formed by coating on the second magnetic shield plate disposed on the side opposite to the stator of the base of the fixing member, compared to the case where an insulating film is bonded with an adhesive as in the prior art. The second magnetic shield plate itself can be thinned, and the entire motor can be thinned.

  Also, each protrusion of the winding locking member is inserted from one side of the through hole, and the tip of the protrusion protruding from the other side of the through hole is melted and locked to the periphery of the through hole. The wire locking member can be reliably fixed to the stator core. Therefore, the winding locking member does not float from the stator core, and the increase in the thickness of the stator due to the lifting of the conventional winding locking member can be prevented, and the motor can be thinned.

  In addition, when each protrusion of the winding locking member is inserted into the through hole, the tip is elastically contracted to allow the insertion to be permitted. On the other hand, if the projection penetrates the through hole and protrudes from the other side, the tip contracts. Is restored. As a result, each protrusion is restricted from moving in the anti-insertion direction with respect to the through hole, and the winding locking member can be firmly fixed to the stator core. As a result, the winding locking member Therefore, the thickness of the stator can be prevented from increasing due to the lifting of the winding locking member as in the prior art, and the motor can be made thinner. Further, since the protrusion is only elastically deformed and inserted into the through hole, even if the rigidity around the through hole of the stator core is low, the winding locking member can be easily fixed to the stator core without deformation of the stator core. .

  In addition, since the first magnetic shield plate is fixed to the upper surface of the stator winding, the first magnetic shield plate is directly attached to the stator, and the motor can be thinned. . Further, since the first magnetic shield plate is brought into contact with the guide portion of the winding locking member, the positioning becomes easy and the first magnetic shield plate can be accurately fixed to the stator.

  Further, since the magnetic plate is disposed between the magnetic disk and the rotor magnet, the magnetic flux of the rotor magnet can be prevented from affecting the magnetic disk. In addition, since this magnetic plate is made of a member different from the rotor, it is not necessary to process a thin portion for preventing magnetic flux leakage, which has been a hindrance to reducing the rotor thickness as in the prior art. As a result, the rotor can be thinned easily, and the motor can be thinned.

  Further, since the magnetic plate is disposed between the magnetic disk and the rotor magnet, the magnetic flux of the rotor magnet can be prevented from affecting the magnetic disk. In addition, since this magnetic plate is made of a member different from the rotor, it is not necessary to process a thin portion for preventing magnetic flux leakage, which has been a hindrance to reducing the rotor thickness as in the prior art. As a result, the rotor can be thinned easily, and the motor can be thinned. Further, since the magnetic plate placed on the upper surface of the rotor magnet is attracted by the magnetic force of the rotor magnet, the magnetic plate can be fixed much more easily than using means such as press fitting or adhesive.

  In addition, since the magnetic plate is formed to have an L-shaped cross section and is interposed between the large diameter portion of the rotor and the rotor magnet, a member that acts as a yoke for the rotor magnet is used as part of the magnetic plate. By doing so, there is no need to increase the number of parts. In particular, when the rotor is formed of a nonmagnetic material, it is desirable to configure in this way.

  Further, since the magnetic plate is disposed between the magnetic disk and the rotor magnet, the magnetic flux of the rotor magnet can be prevented from affecting the magnetic disk. In addition, since this magnetic plate is made of a member different from the rotor, it is not necessary to process a thin portion for preventing magnetic flux leakage, which has been a hindrance to reducing the rotor thickness as in the prior art. As a result, the rotor can be thinned easily, and the motor can be thinned. In addition, the magnetic plate is firmly fastened to the flange because it is fixed by plastically deforming a part of the flange.

  Also, while the magnetic plate is made of a magnetic material having a lower permeability than the rotor, the rotor is made of a magnetic material that has better machinability than the magnetic plate, so that the magnetic flux from the rotor magnet to the magnetic disk side is transmitted. Thus, the influence on the magnetic disk can be surely prevented, and precise machining of the rotor can be easily performed.

It is a partial sectional view of one embodiment of this invention. It is AA arrow sectional drawing of FIG. It is a figure which shows an example of the assembly of the motor in one Embodiment of this invention. It is a figure which shows the some modification of one Embodiment of this invention. It is a figure which shows the one part modification from which one Embodiment of this invention differs. It is a figure which shows a part of another modification of one Embodiment of this invention. It is a partial sectional view of a conventional example. It is a partial cross section figure from which a prior art example differs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 3 Fixing member 3a Base 3b Perimeter wall part 5 Shaft 9 Rotor 11 Stator 13 Magnetic disk 17 Magnetic plate 18 Rotor magnet 21 Stator core 21c Through-hole 23 Winding 29 Resin cover (winding locking member)
29a Locking part 31 Projection part 31a Claw-shaped part (elastic locking part)
33 first magnetic shield plate 33a first plate member (plate member)
33b Resin (film)
43 Second magnetic shield plate 43a Second plate member (plate member)
43b Resin (film)

Claims (6)

A rotor having an annular rotor magnet and a portion on which the magnetic disk is placed on the outer peripheral portion, and a rotor supported rotatably around a central axis;
A stator core having a plurality of magnetic poles radially arranged with the tips directed toward the central axis and an annular core back connecting the radially outer ends of the plurality of magnetic poles, and wound around each of the plurality of magnetic poles A stator provided with a winding, and facing the rotor magnet;
A magnetic shield plate having an axial position between the portion on which the magnetic disk is placed and the winding, and an outer peripheral edge thereof positioned radially inward from an outer peripheral edge of the core back;
A magnetic disk drive motor comprising:   2. The magnetic disk according to claim 1, wherein the outer peripheral edge of the shield plate is located radially inward between the magnetic poles adjacent to each other and a portion where the part of the winding straddling the magnetic poles is locked. Drive motor. A winding locking member is disposed on one side in the axial direction of the stator core,
The winding locking member includes a locking portion that locks a part of the winding straddling between adjacent magnetic poles,
The magnetic disk drive motor according to claim 1, wherein an outer peripheral edge of the shield plate is located radially inward from the locking portion. The winding locking member further includes an annular portion disposed on one side in the axial direction of the core back, and a convex guide portion extending radially inward from the inner peripheral surface of the annular portion,
4. The magnetic disk drive motor according to claim 3, wherein the outer periphery of the magnetic shield plate is positioned in a radial direction by contacting an inner peripheral portion of the guide portion.   5. The magnetic disk drive motor according to claim 1, wherein the magnetic shield plate is fixed by an adhesive to a portion of the winding facing the magnetic shield plate in the axial direction. 6. .   6. The magnetic disk drive motor according to claim 1, wherein an inner peripheral edge of the magnetic shield plate is located radially outward from a tip of the magnetic pole.

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