JPH059179U - Spindle motor - Google Patents

Abstract

(57) [Summary] [Construction] A rotor hub 5 in which a bearing 3 composed of a slide bearing is provided on a printed circuit board 1, a spindle 4 is supported by the bearing 3, and a rotor 5 composed of a permanent magnet is fixed to the spindle 4.
1 and the turntable 6 are fixed, the stator core 8 is fixed to the printed circuit board 1, the outer circumference of the stator core 8 is opposed to the inner circumference of the rotor 5 with a radial gap, and the magnetic poles of the rotor 5 are fixed. The rotor hub 51 is pressed against the end surface 31 of the bearing 3 by the magnetic attraction force generated between the rotor 5 and the stator core 8 or the printed circuit board 1. [Effect] Since the rotor hub is constantly pressed against the end surface of the bearing, the axial displacement can be reduced without providing the thrust receiver.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

  The present invention is used for a floppy disk drive device and a drive device for audiovisual equipment. Related to a spindle motor.

[0002]

[Prior art]

  Conventionally, as shown in FIG. 3, a spindle motor has a control unit for the spindle motor. The bearing housing 2 is fixed to the mounted printed circuit board 1 and the inner circumference of the bearing housing 2 is fixed. The bearing 3 is fitted to the shaft 3, and the spindle 3 is supported by the bearing 3. A rotor hub 51 to which a ring-shaped rotor 5 made of a permanent magnet is fixed is fixed to the end portion. Turntable 6 to which a disc storing information is attached at the other end It is fixed. A stator core 8 having an armature coil 7 is fixed to the printed circuit board 1. The outer circumference of the stator core 8 faces the inner circumference of the rotor 5 with a radial gap. I have to.   In this case, in order to reduce the axial displacement due to the external force of the rotor, the bearing 3 has a ball When using bearings or sliding bearings, as shown in Figure 4, 1 is provided with a thrust receiver 33 to press the end of the spindle 4 (for example, a special (Kaisho 61-18339, JP-A 62-155759).

[0003]

[Problems to be solved by the device]

  However, with the above configuration, the cost is high when ball bearings are used, and sliding bearings are used. When it is used, there is a drawback that the number of parts is large and the number of assembling steps is increased.   The present invention can reduce the cost by using plain bearings without increasing the number of parts. The purpose is.

[0004]

[Means for Solving the Problems]

  According to the present invention, a bearing is provided on a printed circuit board, and the spindle is supported by the bearing. Rotor hub and turntable in which a rotor made of a permanent magnet is fixed to the spindle And the stator core on the printed circuit board, and the outer circumference of the stator core. In a spindle motor in which the rotor is opposed to the inner circumference of the rotor with a radial gap. , The plain bearing is directly fixed to the printed circuit board, and The rotor hub is pressed against the end surface of the bearing by the magnetic attraction generated by the poles It was done so.   Especially, the axial center of the rotor is eccentric to the axial center of the stator core. , The rotor core is attracted by the attractive force generated between the stator core and the magnetic poles of the rotor. The bumps generate an axial component that presses the end surface of the bearing.   In addition, the printed circuit board is composed of a metal-based printed circuit board made of a magnetic material. , Is opposed to the side surface of the rotor with a gap.

[0005]

[Action]

  Shift the axial centers of the stator core and the rotor composed of permanent magnets to fix the rotor. Generates an axial component of the suction force that presses the fixed rotor hub against the end surface of the plain bearing. Since the rotor hub is always pressed against the end surface of the plain bearing, Similarly, reduce the axial displacement.

[0006]

【Example】

  The present invention will be described with reference to the embodiments shown in the drawings.   FIG. 1 is a side sectional view showing an embodiment of the present invention. The spindle 3 is supported by the bridge 3, and one end of the spindle 4 is made of a permanent magnet. The rotor hub 51 to which the rotor 5 is fixed is fixed, and the turntable 6 is fixed to the other end. Fixed, the stator core 8 having the armature coil 7 is fixed to the printed circuit board 1, and the stator is fixed. The configuration in which the outer circumference of the iron core 8 is opposed to the inner circumference of the rotor 5 with a radial gap in between is conventional. It is almost the same.   It differs from the conventional one in the following points. That is, the bearing 3 is composed of a sliding bearing such as an oil-impregnated alloy. Then, the flange portion 32 is provided on the bearing 3, and the flange portion of the bearing 3 is directly provided on the printed circuit board 1. 32 is fixed. The axial center of the rotor 5 with respect to the axial center of the stator core 8 By the eccentric amount e. In addition, the rotor hub 51 generates an axial component that pushes the end surface 31 of the bearing 3. It   FIG. 2 shows an embodiment in which the rotor hub 51 is arranged above the bearing 3.   Also in this case, the rotor hub 51 is always pressed against the end surface 31 of the bearing 3. Thus, the axial displacement can be reduced even when an axial external force is applied to the rotor. .   It should be noted that the printed circuit board 1 is subjected to an insulation treatment on a magnetic material such as a steel plate, and the printed board 1 Printed circuit board 1 when using a metal-based printed circuit board with a printed circuit board The rotor 5 is made to face the side surface with a gap. At this time, the leakage flux of the rotor 5 Since the lint substrate 1 is constantly sucked to press the rotor hub 51 against the bearing 3, It is not necessary to make the stator core 5 and the stator core 8 eccentric.

[0007]

[Effect of device]

  As described above, according to the present invention, the rotor hub is always pressed against the end surface of the bearing. Since it is designed so that it is not necessary to provide thrust receivers, the cost is low. Sliding bearings can be used, and the number of work steps can be reduced, resulting in low cost There is an effect that a pindle motor can be provided.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a side sectional view showing another embodiment of the present invention.

FIG. 3 is a side sectional view showing a conventional example.

FIG. 4 is a side sectional view showing another conventional example.

[Explanation of symbols]

1 printed circuit board, 3 bearings 32 Flange 4 spindles 5 rotor 51 rotor hub 6 turntable 7 Armature coil 8 Stator core

Claims (3)

[Scope of utility model registration request] 1. A printed circuit board is provided with a bearing, a spindle is supported by the bearing, a rotor hub having a rotor made of a permanent magnet is fixed to the spindle, and a turntable is fixed, and a stator core is fixed to the printed circuit board. Then, in a spindle motor in which the outer circumference of the stator core is opposed to the inner circumference of the rotor with a radial gap, the bearing, which is a sliding bearing, is fixed to the printed circuit board and is generated by the magnetic pole of the rotor. The rotor hub is pressed against the end surface of the bearing by the magnetic attraction force. 2. The rotor hub is urged by the attraction force generated between the stator core and the magnetic pole of the rotor by eccentricizing the center of the rotor in the axial direction with respect to the center of the stator core. The spindle motor according to claim 1, wherein an axial component for pressing the end face of the spindle motor is generated. 3. The spindle motor according to claim 1, wherein the printed circuit board is composed of a metal-based printed circuit board made of a magnetic material, and is opposed to a side surface of the rotor with a gap.