JPH0636358U - Dynamic bearing motor - Google Patents

Abstract

(57) [Summary] [Purpose] By providing a simple position holding means,
Prevents the rotating body from coming off the shaft. [Structure] A radial dynamic pressure bearing is configured between a rotating body (hub 4 and the like) and a shaft 2, a drive magnet 6 is arranged on the rotating body, and a stator 7 is arranged so as to face the drive magnet 6. The position holding means 2 is fixed to the stator support (frame 1) and at least between the stator 7 and the rotating body.
0 and 21 are provided. [Effect] It is possible to regulate the axial position of the rotating body with respect to the fixed stator, and even if the dynamic pressure bearing motor is impacted, the rotating body may slip out of the shaft,
Alternatively, it is possible to prevent the rotating body from largely moving.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a dynamic pressure bearing motor that supports a rotating body by a dynamic pressure bearing.

[0002]

[Prior art]

 As a dynamic pressure bearing motor of this type, there is a motor used in a magnetic disk drive device as shown in FIG. In this motor, a shaft 2 is fixed to a frame 1, and a dynamic pressure bearing body 3 is rotatably fitted on the outer periphery of the shaft 2. On the inner circumference of the dynamic pressure bearing body 3, there is formed a spiral groove (not shown) formed of a substantially spiral groove. When the hydrodynamic bearing body 3 rotates, a fluid such as lubricating oil or air interposed between the shaft 2 and the spiral groove generates a levitation force between the shaft 2 by the spiral groove pumping action. The dynamic pressure bearing body 3 is rotatably supported on the shaft 2 in a non-contact state. The dynamic pressure bearing body 3 is fitted in the inner hole 4 a of the hub 4. A magnetic disk (not shown) is mounted on the outer circumference of the hub 4, and a floating magnetic head that is sought by an actuator faces the magnetic disk. A thrust receiving plate 5 which is in contact with the tip of the shaft 2 is press-fitted and fixed in the upper end side opening of the inner hole 4a of the hub 4.

An annular flange 4b is integrally formed on the lower end of the outer periphery of the hub 4, and a drive magnet 6 is fixed to the inner peripheral surface of the annular flange 4b. Further, a stator core 7 is fixed to a support made up of the frame 1, the stator core 7 has a plurality of salient poles, and a coil 8 is wound around each salient pole. The outer peripheral surface of the stator core 7 faces the inner peripheral surface of the drive magnet 6 with a gap. A motor is constituted by the stator core 8, the drive magnet 6, and the like, and the hub 4 is integrally rotated by urging the drive magnet 6 to rotate. Further, a labyrinth seal portion 9 is formed between the lower end of the annular collar portion 4b of the hub 4 and the frame 1. The labyrinth seal portion 9 is provided to separate the space for mounting the magnetic disk from the space for the motor.

[0004]

[Problems to be solved by the device]

 In the above dynamic pressure bearing motor, the rotating body including the dynamic pressure bearing body 3 and the hub 4 is fitted and inserted in the shaft 2. Therefore, the stator core 7 and the drive magnet 6 are opposed to each other, so Although the drive magnet 6 is attracted by a magnetic attraction force, the hub 4 sometimes slips out of the shaft 2 when an impact is applied to the motor. Therefore, when an impact is applied, the movement of the rotating body may damage the spiral groove or the like of the dynamic pressure bearing body 3, and in some cases, it may be impossible to rotate. There is.

The present invention has been made in order to solve such a problem, and by providing a simple position holding means, it is possible to prevent the rotating body from coming off the shaft. The purpose is to provide a motor.

[0006]

[Means for Solving the Problems]

 According to the present invention, a radial dynamic pressure bearing is formed between a rotating body and a shaft, a driving magnet is disposed on the rotating body, and a stator is fixed to a stator support so as to face the driving magnet. Position holding means is provided at least between the stator and the rotating body.

[0007]

[Action]

 If the position holding means is provided between the stator fixed to the stator support and the rotating body, the axial position of the rotating body is restricted with respect to the fixed stator, so that impact is applied to the dynamic pressure bearing motor. Even if it does, it is possible to prevent the rotor from slipping out of the shaft and to prevent the rotor from moving significantly.

[0008]

【Example】

 An embodiment of a dynamic pressure bearing motor according to the present invention will be described below with reference to the drawings. Incidentally, FIG. 1 shows a dynamic pressure bearing motor for a magnetic disk drive similar to that of FIG. 3, the same reference numerals as those in FIG. That is, the dynamic pressure bearing body 3 is rotatably fitted on the outer periphery of the shaft 2 fixed to the frame 1, and the spiral groove formed of a substantially spiral groove is formed on the inner periphery of the dynamic pressure bearing body 3. A radial dynamic pressure bearing is formed by forming the above, and the inner hole 4a of the hub 4 is fitted to the outer circumference of the dynamic pressure bearing body 3 as in the example shown in FIG. The embodiment of FIG. 1 differs from that of FIG. 3 in that a position holding means is provided at least between the stator and the rotating body.

That is, as the position holding means shown in FIG. 1, a ring-shaped permanent member fixed to the bottom surface of the hub 4 is provided on the inner and outer flat surfaces of the stator core 7 fixed to the stator support body including the frame 1. The magnets 20 and 21 are attached so as to face each other. The permanent magnets 20 and 21 face the plane of the stator core 7 to magnetically attract the hub 4 to the stator core 7. Therefore, the attraction force, which is the magnetic attraction force generated by the stator core 7 and the drive magnet 6 described above, acts on the hub 4, and the hub 4 can be held at the normal position even if a shock is applied to the motor. it can. The attraction force of the permanent magnets 20 and 21 is set by an assumed impact force, and may be one permanent magnet in some cases.

FIG. 2 shows another embodiment as a position holding means. The outer peripheral surface of the stator core 17 is formed so as to have a smaller diameter toward the hub 4 to form a substantially truncated cone shape, while a drive magnet is formed. The inner peripheral surface of 16 is formed obliquely along the outer peripheral surface of the stator core 17. As a result, the facing gap between the outer peripheral surface of the stator core 17 and the inner peripheral surface of the drive magnet 16 is inclined, and the vector of the attractive force of the drive magnet 16 increases downward. Therefore, a large suction force is applied to the hub 4, and the hub 4 can be held at the normal position even if a shock is applied to the motor as in the above-mentioned example.

In the embodiment described above, the hub 4 is provided with the permanent magnets 20 and 21 to face the stator core 7, or the facing angle between the drive magnet 16 fixed to the hub 4 and the stator core 17 is slanted. As a result, the position holding means for increasing the magnetic attraction force is constructed.This is the case of the dynamic pressure bearing motor for the magnetic disk drive, and in the case of the motor of the general construction, the rotating body is used. The rotor may be a normal rotor, and the stator support is not limited to the frame 1 and may have any other structure as long as it fixes a stator core such as a stator substrate, and the like without departing from the scope of the present invention. Can be changed in various ways.

[0012]

[Effect of device]

 As is apparent from the above description, since the dynamic bearing motor of the present invention has the position holding means between the stator fixed to the stator support and the rotating body, the rotating body is fixed relative to the fixed stator. The axial position of the rotor can be regulated, and even if a shock is applied to the dynamic pressure bearing motor, it is possible to prevent the rotor from slipping out of the shaft or the rotor moving significantly. There are advantages.

[0013]

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a dynamic pressure bearing motor according to the present invention.

FIG. 2 is a sectional view of an essential part showing another embodiment of the position holding means.

FIG. 3 is a cross-sectional view showing a conventional dynamic pressure bearing motor.

[Explanation of symbols]

 1 frame (stator support) 2 shaft 3 dynamic pressure bearing 4 hub 6 drive magnet 7 stator core (stator) 20,21 permanent magnet

Claims (1)

[Scope of utility model registration request] 1. A radial dynamic pressure bearing is provided between a rotating body and a shaft, a drive magnet is disposed on the rotating body, and a stator is fixed to a stator support so as to face the drive magnet. , A dynamic bearing motor comprising position holding means at least between the stator and the rotating body.