JP2006005973A - Brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brushless motor in which a thrust cap is not removed or a position is not shifted even when a large force is applied in a thrust direction from a shaft.
SOLUTION: A shaft 2, a sleeve 3 that rotatably supports the shaft 2 in the radial direction, a bearing housing 3 that holds the sleeve 3, and a bottomed cylindrical shape that receives the thrust force of the shaft 2 at the bottom. The thrust cap 5 and a mounting base 9 to which the thrust cap 5 is assembled are provided. The thrust cap 9 is formed with a step portion 5b so that a portion opposite to the bottom portion is thick. The step portion 5 b is in contact with the mounting base 9. With this configuration, even when a large force is applied from the shaft 2 to the thrust cap 5 in the thrust direction, this force is received by the mounting base 9 via the step portion 5b of the thrust cap 5, and the thrust cap 5 is removed or positioned. Is prevented from shifting.
[Selection] Figure 1

Description

  The present invention relates to a brushless motor used for a disk drive device or the like.

  As a brushless motor used in disk drive devices that rotate disk-shaped recording media such as optical disks and magnetic disks, the rotor shaft is made up of a cylindrical sleeve impregnated with oil and a disk-shaped thrust plate. Those which are received and supported in a freely rotatable manner are known (for example, Patent Documents 1 to 3).

  FIG. 8 shows a conventional brushless motor of this type, in which a shaft 51 is received in a radial direction by a bottomless cylindrical sleeve 52 impregnated with oil and supported rotatably, and the pivot shape of the shaft 51 is shown. The bottom surface portion is received by a resin thrust plate 53 formed in a disc shape and is rotatably supported. The sleeve 52 is press-fitted and held from the outer peripheral side by a cylindrical bearing housing portion 54 a provided on the bracket 54 so as not to rotate in the circumferential direction. The bracket 54 includes a bearing housing portion 54a, a large diameter cylindrical portion 54b connected to the bearing housing portion 54a via a stepped portion, and an attachment base portion 54c connected to the bottom portion of the large diameter cylindrical portion 54b. Are integrally formed. A bottomed cylindrical thrust cap 55 is fitted in the inner peripheral side of the large-diameter cylindrical portion 54 b of the bracket 54 in a press-fit state, and the thrust plate 53 is fixed on the bottom surface portion of the thrust cap 55.

  A stator core 56 is fitted into the outer periphery of the bearing housing portion 54 a of the bracket 54 in a press-fit state, and a coil 66 is wound around a tooth portion provided on the stator core 56. On the other hand, the inner peripheral cylindrical portion of the rotor frame 57 is press-fitted and fixed to the upper portion of the shaft 51, and a ring-shaped rotor magnet 58 faces the stator core 56 on the inner surface of the outer peripheral cylindrical portion of the frame 57. Fixed in posture.

  In FIG. 8, 59 is a turntable fixed to the upper end of the shaft 51, and a disk-shaped recording medium is detachably attached. 62 is oil leaking from the upper part of the sleeve 52 to the stator core 56 side. The cylindrical member 62 is fitted in a press-fitted state between the inner peripheral surface of the stator core 56 and the outer peripheral surface of the sleeve 52. A printed circuit board 64 is provided with an electric circuit such as a drive control circuit. Reference numeral 70 denotes a ring-shaped magnet component fixed to a position near the inner periphery of the upper surface of the stator core 56. By attracting the frame 57 by the magnetic force of the magnet component 70, the shaft 51 moves upward even while the shaft 51 is rotating. It is difficult to improve the positioning accuracy in the thrust direction.

This conventional brushless motor is assembled in the following steps.
As shown in FIG. 9, first, the printed circuit board 64 is attached to the attachment base portion 54 c of the bracket 54 with the double-sided tape 65. Next, as shown in FIGS. 10A and 10B, the stator core 56 around which the coil 66 is wound is fitted in the outer periphery of the bearing housing portion 54a of the bracket 54 in a press-fit state, as shown in FIG. In addition, the sleeve 52 is inserted into the inner periphery of the bearing housing portion 54a of the bracket 54 in a press-fit state, and is fixed so that the sleeve 52 and the bracket 54 do not move in the circumferential direction relatively. Further, the cylindrical member 62 is fitted between the inner peripheral surface of the stator core 56 and the outer peripheral surface of the sleeve 52 in a press-fitted state.

  In parallel with this, as shown in FIG. 12, the shaft 51 is inserted into the outer peripheral surface of the inner cylindrical portion of the frame 57 in a press-fitted state. A ring-shaped rotor magnet 58 is fixed in advance to the inner surface of the outer peripheral cylindrical portion of the frame 57.

  Then, as shown in FIG. 13, the stator core 56, the bracket 54, and the like are assembled, and the shaft 51 is inserted into the sleeve 52 impregnated with oil so that the stator core 56 and the like are housed in the frame 57.

Thereafter, as shown in FIG. 14, the assembly in which these components are assembled is placed upside down on a mounting table 67 on which a plurality of position regulating pins 68 are erected. At this time, the position restriction pin 68 inserted through the insertion hole 57a formed in the frame 57 contacts the tip of the cylindrical member 62, and the bracket 54 whose tip contacts the cylindrical member 62 also moves downward. To be regulated. In this way, with the position restricted so that the bracket 54 does not move downward, the thrust cap 55 to which the thrust plate 53 is fixed is press-fitted into the large-diameter cylindrical portion 54b of the bracket 54 and assembled. As a result, as shown in FIG. 15, the pivot-shaped bottom surface portion of the shaft 51 is in sliding contact with the thrust plate 53, and the motor is completed. Thereafter, a member to be rotated, such as a turntable 59, is attached to the shaft 51 as necessary.
JP 2000-125505 A JP-A-8-289523 JP 2002-262540 A

  However, in the conventional brushless motor, as shown in FIG. 14, the cylindrical portion of the thrust cap 55 is simply press-fitted from below into the large-diameter cylindrical portion 54b of the bracket 54 and assembled. Because of the structure, when a large force acts in the thrust direction from the shaft 51 via the turntable 59 or the like, the thrust cap 55 comes off from the large-diameter cylindrical portion 54b of the bracket 54, and the position of the thrust cap 55 shifts. There was a fear.

  In addition, since the stator core 56 is fitted into the outer peripheral surface of the bearing housing portion 54a of the bracket 54 holding the sleeve 52 in a press-fitted state, the deformation of the bearing housing portion 54a during the press-fitting of the stator core causes the sleeve 52 to be removed. There is a problem in that it directly affects the fitting portion, and as a result, directly affects the perpendicularity of the sleeve 52 and the shaft 51 with respect to the mounting base portion 54c. Similarly, there is a problem that heat and vibration generated in the stator core 56 are easily transmitted to the sleeve 52 through the bearing housing portion 54a, and the reliability of the bearing performance of the sleeve 52 is lowered.

  The present invention solves the above problems and problems, and even when a large force is applied in the thrust direction from the shaft, there is no possibility that the thrust cap will be removed or displaced, and deformation due to press-fitting of the stator core will be adversely affected. Further, it is an object to provide a brushless motor in which heat and vibration generated in a stator core are not easily transmitted to a sleeve.

  In order to solve the above problems and problems, a brushless motor of the present invention includes a shaft, a sleeve that rotatably supports the shaft in the radial direction, a bearing housing that holds the sleeve, and a thrust force in the shaft in the bottom portion. The thrust cap has a bottomed cylindrical shape and a mounting base to which the thrust cap is assembled. The thrust cap is formed with a stepped portion so that a portion opposite to the bottom is thickened. The step portion is in contact with the mounting base.

  According to this configuration, since the step portion of the thrust cap is in contact with the mounting base, even when a large force acts in the thrust direction from the shaft, this force is received by the mounting base via the step portion of the thrust cap. This prevents the thrust cap from being removed or displaced.

  Further, according to the present invention, a portion where the thrust cap is mounted on the mounting base is formed so as to protrude in a cylindrical shape, and the thrust cap is attached to the mounting base in such a posture that the stepped portion of the thrust cap is received by the end surface of the mounting cylindrical portion. It is characterized by being assembled.

  As described above, the thrust cap stepped portion is received by the end surface of the mounting cylindrical portion, so that, for example, a larger force is better than when the thrust cap stepped portion is received by the flat plate portion of the mounting base. It can be received and supported.

  Further, according to the present invention, the thick cylindrical portion formed thicker through the step portion in the thrust cap is disposed so as to have a gap with respect to the bearing housing, and the stator core is disposed outside the large diameter cylindrical portion. It is attached.

  With this configuration, the stator core can be supported by the large-diameter cylindrical portion of the thrust cap, but the deformation when the stator core is press-fitted and assembled by the gap between the bearing housing and the vibration and heat from the stator core are affected by the bearing housing. It becomes difficult to be transmitted to.

  As described above, according to the present invention, since the step portion of the thrust cap is in contact with the mounting base, even if a large force acts in the thrust direction from the shaft, this force is transmitted through the step portion of the thrust cap. Receiving by the mounting base, it is possible to prevent the thrust cap from being removed or displaced, and the reliability is improved.

  In addition, by forming a portion of the mounting base where the thrust cap is mounted so as to protrude in a cylindrical shape, the thrust cap is assembled to the mounting base in a posture to receive the stepped portion of the thrust cap by the end surface of the mounting cylindrical portion. Even when a greater force acts in the thrust direction from the shaft, this force can be reliably received, and the reliability is further improved.

  Further, by arranging the thick cylindrical portion formed thick via the stepped portion in the thrust cap so as to have a gap with respect to the bearing housing, by attaching a stator core to the outside of the large cylindrical portion, While the stator core can be supported by the large-diameter cylindrical portion of the thrust cap, due to the gap with the bearing housing, deformation when the stator core is press-fitted and assembled, and vibration and heat from the stator core are not easily transmitted to the bearing housing. The adverse effects of the deformation are suppressed, the reliability as a motor is improved, and the life of the motor as a bearing is extended.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, for ease of understanding, the case where the vertical direction in FIG. 1 is arranged along the vertical direction is described, but the motor and its components are limited to being arranged in such a direction. Not what you want.

  As shown in FIG. 1, a brushless motor according to an embodiment of the present invention includes a shaft 2 having a turntable 1 on which a disk-shaped recording medium is detachably attached, and a porous metal material. For example, a bottomless cylindrical sleeve 3 that is impregnated with oil and rotatably supports the shaft 2 in the radial direction, and a substantially bottomless cylindrical shape that is externally fitted to the sleeve 3 and holds the sleeve 3. A bearing housing 4, a bottomed cylindrical thrust cap 5 fitted and assembled to the outer periphery of the bearing housing 4 and receiving the thrust force of the shaft 2 through a thrust plate 6 and a thrust magnet 7, and a shaft An annular retaining member 8 that is fitted on the outer periphery of the bottom portion 2 to prevent the shaft 2 from being pulled upward, and a thrust cap 5 is assembled in the center hole. The base 9, the printed circuit board 10 mounted on the mounting base 9 and provided with an electric circuit such as a drive control circuit, and the outside of the large-diameter cylindrical portion 5 c formed on the upper side of the thrust cap 5 A stator core 11 fitted and attached, a coil 12 wound around a tooth portion provided on the stator core 11, and a rotor whose inner cylindrical portion is press-fitted and fixed to the upper portion of the shaft 2. A frame 13 and a ring-shaped rotor magnet 14 fixed in a posture facing the stator core 11 on the inner surface of the outer peripheral cylindrical portion of the frame 13 are provided.

  Here, the upper portion of the bearing housing 4 is extended further upward than the upper end of the sleeve 3 with a slight gap from the outer periphery of the sleeve 3, and the sleeve 3 is covered from the outer peripheral side by the bearing housing 4. The oil impregnated in the sleeve 3 is prevented from scattering outside.

  The sleeve 3 is attached to the attachment base 9 via the thrust cap 5 and the bearing housing 4. In this case, the relative position of the bearing housing 4 with respect to the thrust cap 5 can be adjusted. The bearing housing 4 and the thrust cap 5 are fixed to each other by an adhesive 15 as a fixed body. More specifically, as shown in FIG. 2B, a plurality of slits 16 are cut into the cylindrical portion of the bearing housing 4 that fits with the thrust cap 5 at predetermined angles along the axial direction. In the state where the bearing housing 4 is merely fitted to the thrust cap 5 before the adhesive 15 is applied in a subsequent process, as shown in FIG. For example, the position of the bearing housing 4 with respect to the thrust cap 5 can be adjusted by using a jig such as a holding pin 18. Further, as shown in FIG. 2 (a), a part of the outer periphery of the sleeve 3 (may be a part of the inner periphery of the thrust cap 5) is a step when the shaft 2 is inserted into the sleeve 3 to be described later. A groove passage 3a for discharging the air in the thrust cap 5 to the outside is formed.

  The thrust cap 5 includes a thin cylindrical portion 5h extending upward from the bottom surface portion thereof, a step portion 5b formed at the upper end of the thin cylindrical portion 5h and extending in the radial direction, and the step portion 5b. The large-diameter cylindrical portion 5c formed to extend upward from the portion 5b. The large-diameter cylindrical portion 5c of the thrust cap 5 is between the bearing housing 4 and more specifically, the sleeve 3 in the bearing housing 4. Is provided with a gap between the outer peripheral portion of the portion where is fitted. And the adhesive agent 15 is inject | poured into the location near the step part 5b in this clearance gap, and the bearing housing 4 and the thrust cap 5 are adhering. In addition, the stator core 11 is attached so that the inner periphery of the lower half of the stator core 11 is press-fitted into the outer periphery of the portion above the injection point of the adhesive 15 in the thick cylindrical portion 5c of the thrust cap 5. .

  The thrust cap 5 is in a state in which the thin cylindrical portion 5h is press-fitted into the inner periphery of the mounting cylindrical portion 9a integrally formed so as to protrude upward from the central hole portion of the mounting base 9 in a cylindrical shape. It is attached. Then, the thrust cap 5 is assembled to the mounting base 9 in such a posture that the end portion 5b of the thrust cap 5 is received by the end surface of the mounting cylindrical portion 9a in the mounting base 9, and the thrust cap 5 is prevented from being detached downward. ing.

  Further, as described above, the retaining member 8 is disposed in the space between the thrust cap 5 and the bottom portion of the shaft 2, and the retaining member 8 is fitted on the outer periphery of the bottom portion of the shaft 2 in a press-fit state. Even when the shaft 2 is about to move upward, the retaining member 8 abuts against the lower end of the sleeve 3 to prevent the shaft 2 from coming upward. In addition to the thrust plate 6 made of resin, a thrust magnet 7 is also fixed on the bottom surface of the thrust cap 5, and not only the shaft 2 but also the retaining member 8 is made of a material that receives magnetic force. By attracting the shaft 2 and the retaining member 8 so as not to be pulled out upward by the magnetic force, the upward movement-preventing force of the shaft 2 is strengthened. As shown in FIGS. 1 and 7, a plurality of position regulating pins 17 that support the retaining member 8 from below when the retaining member 8 is press-fitted into the outer periphery of the bottom of the shaft 2 at the bottom of the thrust cap 5. A through-hole 5d is formed for passing through.

Next, the procedure for assembling the brushless motor will be described.
As shown in FIG. 3A, first, the printed board 10 is attached to the upper surface of the attachment base 9. In this embodiment, as shown in FIG. 3 (a), a riveting process (the rivet portion is indicated by L in FIG. 3 (a), but this portion is omitted in other drawings). Thus, the printed circuit board 10 is attached to the attachment base 9, and there is an advantage that the double-sided tape that has been used conventionally is unnecessary, but this is not restrictive. Further, the thrust magnet 7 and the thrust plate 6 are fixed on the bottom surface of the thrust cap 5. Further, the retaining member 8 is accommodated in the thrust cap 5.

  Next, in this state, as shown in FIG. 3 (b), the portion from the bottom of the thrust cap 5 to the thin cylindrical portion 5 h is placed in the mounting cylindrical portion 9 a of the mounting base 9. The stepped portion 5b is fitted and fixed in a press-fit state until the lower surface of the stepped portion 5b contacts the tip of the mounting tubular portion 9a of the mounting base 9.

  On the other hand, as shown in FIG. 4 (a), a bearing housing 4 is fitted on a sleeve 3 impregnated with oil and assembled, and the lower portion of the bearing housing 4 with the sleeve 3 assembled in this manner is shown in FIG. As shown to b), it is made to fit in the small diameter cylindrical part 5h of the thrust cap 5. FIG. At this time, since the slit 16 is formed in the portion of the bearing housing 4 to be fitted to the small diameter cylindrical portion 5h, the bearing housing 4 is fitted in a state where it is press-fitted with a relatively small force (so-called light press-fitted state). Combined. In this state, the pressing pin 18 for adjusting the verticality is applied to the upper end portion of the bearing housing 4 and the like so that the shaft core of the sleeve 3 is adjusted to have a good verticality with respect to the mounting base 9.

  Then, in a state in which a posture in which good perpendicularity is obtained is maintained, as shown in FIG. 4 (c), an adhesive 15 is injected between the bearing housing 4 and the thin cylindrical portion 5h and cured. The bearing housing 4 in which the sleeve 3 is assembled and the thrust cap 5 in the mounting base 9 are fixed.

  Thereafter, as shown in FIG. 5, the stator core 11 around which the coil 12 is wound is fitted and assembled to the large-diameter cylindrical portion 5 c of the thrust cap 5. Further, as shown in FIG. 6, the shaft 2 is inserted and fixed in advance in a press-fit state on the frame 13 to which the ring-shaped rotor magnet 14 is fixed, and thus the shaft to which the frame 13 is fixed. 2 is inserted into the sleeve 3 until the bottom surface thereof abuts against the thrust plate 6. At this time, the position restricting pin 17 is passed upward from a through hole 5d provided at the bottom of the thrust cap 5, and the retaining member 8 is supported from below at the tip thereof to prevent the retaining at a predetermined position on the bottom of the shaft 2. The shaft 2 to which the frame 13 or the like is fixed is inserted while restricting the member 8 to be press-fitted. As a result, the brushless motor is completed. Thereafter, as shown in FIG. 7, a rotation target component such as the turntable 1 is attached to the shaft 2 as necessary.

  According to the above configuration, the thrust cap 5 that receives the thrust force of the shaft 2 at the bottom portion is formed with the step portion 5b so as to spread in the radial direction, and the step portion 5b is brought into contact with the mounting base 9. Even when a large force acts in the thrust direction (downward in FIG. 1) from the shaft 2 via the turntable 1, this force is received by the mounting base 9 via the step portion 5 b of the thrust cap 5. Therefore, the thrust cap 5 is prevented from being detached from the mounting base 9 and the assembly position with respect to the mounting base 9 is prevented from shifting, and the reliability of the motor as a bearing is improved.

  Further, a portion of the mounting base 9 where the thrust cap 5 is mounted is formed so as to protrude in a cylindrical shape, and the thrust cap 5 is mounted in such a posture that the stepped portion 5b of the thrust cap 5 is received by the end surface of the mounting cylindrical portion 9a. By assembling to the base 9, even when a larger force is applied in the thrust direction from the shaft 2 side, this force can be reliably received, and the reliability is further improved.

  In addition, a thick cylindrical portion 5c that is thickly formed through a step portion 5b in the thrust cap 5 is disposed so as to have a gap with respect to the bearing housing 4, and a stator core is disposed outside the large diameter cylindrical portion 5c. 11, the stator core 11 can be satisfactorily supported by the large-diameter cylindrical portion 5c of the thrust cap 5, and the deformation when the stator core 11 is press-fitted and assembled by the gap between the bearing housing 4 and It becomes difficult for vibration and heat from the stator core 11 to be transmitted to the bearing housing. Therefore, the adverse effect on the perpendicularity of the sleeve 3 and the shaft 2 to the mounting base 9c due to the deformation of the large-diameter cylindrical portion 5c due to the press-fitting of the stator core 11 can be minimized, and the heat from the stator core 11 can be transferred to the bearing housing 4. As a result, it is difficult to transmit to the sleeve 3 and the shaft 2, and as a result, it is difficult to cause adverse effects such as the thrust plate 6 being easily worn by heat, and vibration between the sleeve 3 and the shaft 2 can be minimized. Reliability is also improved.

  In the above-described embodiment, the case where the bearing housing 4 and the thrust cap 5 are substantially cylindrical has been described. However, the present invention is not limited to this, and may be adapted to the shape of the outer peripheral side of the sleeve 3. It is also possible to form the outer peripheral side of 3 in a square shape, and to form the bearing housing 4 and the thrust cap 5 in a substantially rectangular tube shape.

  The brushless motor of the present invention can be applied not only to a brushless motor but also to various motors.

Sectional drawing of the brushless motor which concerns on embodiment of this invention (A) is a cross-sectional plan view of the brushless motor sleeve and the bearing housing at a fitting position. (B) is a perspective view of the sleeve of the brushless motor and the bearing housing. (A), (b) is sectional drawing which shows the process of assembling the thrust cap of the same brushless motor to a mounting base, respectively. (A) is a sectional view showing a state in which the sleeve of the brushless motor is assembled to the bearing housing. (B) is a sectional view showing the adjustment operation of the bearing housing and sleeve of the brushless motor. (C) is a fixing of the brushless motor. Sectional drawing which shows the state which inject | poured the adhesive agent as a body Sectional drawing which shows the state which assembled the stator core of the same brushless motor Sectional drawing which shows the state which attaches the shaft and flame | frame of the brushless motor Sectional drawing which shows the state which attaches a turntable to the same brushless motor Cross-sectional view of a conventional brushless motor Sectional drawing which shows the state which assembled the printed circuit board of the conventional brushless motor to a bracket (A) is sectional drawing which shows the state which assembled | attached the stator core of the conventional brushless motor (b) is sectional drawing which shows the state which assembled the stator core of the conventional brushless motor Sectional drawing which shows the state which assembled | attached the O-ring of the conventional brushless motor Sectional drawing which shows the state which assembles a shaft and a retaining member to the frame of the conventional brushless motor Sectional drawing which shows the state which assembled | attaches the flame | frame, shaft, etc. of the conventional brushless motor to a sleeve etc. Sectional drawing which shows the state which attaches the thrust cap of the conventional brushless motor Sectional drawing which shows the state which attaches a turntable to the conventional brushless motor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turntable 2 Shaft 3 Sleeve 4 Bearing housing 5 Thrust cap 5b Step part 5c Large diameter cylindrical part 5h Small diameter cylindrical part 6 Thrust board 7 Thrust magnet 8 Retaining member 9 Mounting base 9a Mounting cylindrical part 10 Printed circuit board 11 Stator core 12 Coil 13 Frame 14 Rotor magnet 15 Adhesive (fixed body)
16 Slit 17 Position restriction pin 18 Holding pin

Claims (3)

A shaft,
A sleeve that rotatably supports the shaft in the radial direction;
A bearing housing that holds the sleeve;
A bottomed cylindrical thrust cap that receives the thrust force of the shaft at the bottom,
A mounting base to which the thrust cap is assembled;
In the thrust cap, a step is formed so that a portion on the opposite side to the bottom is thick,
A brushless motor characterized in that a step portion of the thrust cap is in contact with a mounting base.   The location where the thrust cap is mounted on the mounting base is formed so as to protrude in a cylindrical shape, and the thrust cap is assembled to the mounting base in such a manner that the end portion of the mounting cylindrical portion receives the stepped portion of the thrust cap. The brushless motor according to claim 1.   A large-diameter cylindrical portion formed thickly through a stepped shape portion in the thrust cap is disposed so as to have a gap with respect to the bearing housing, and a stator core is attached to the outside of the large-diameter cylindrical portion. The brushless motor according to claim 1, wherein the motor is a brushless motor.

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