JPH0923630A - Brushless motor - Google Patents

Abstract

(57) [Abstract] [Purpose] In a brushless motor used in a magnetic disk drive, a vibration noise caused by a low joint strength between a hub and a rotor frame is solved, and a low noise that does not hinder the magnetic disk drive. It aims at providing the brushless motor of. The rotor frame 7 is bent along the inner peripheral surface of the hub 1 and is joined to the hub 1. The magnet 8 is installed on the inner circumference of the rotor frame 7 so as to face the core 6. The retaining member 9 is provided with a screw portion 9a, and is installed by tightening the screw portion 3a of the sleeve 3 with a screw. As described above, by bending the rotor frame 7 to increase the number of joints with the hub 1, the strength of the joints is increased and the vibration source at the time of driving the motor is eliminated, thus reducing the noise of the motor body. It can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor (hereinafter abbreviated as a motor) used mainly in a magnetic disk drive.

[0002]

2. Description of the Related Art In recent years, HDD devices in the field of office automation have been increasing in density and rotating at high speeds, and a motor for driving a disk is required to have stable accuracy, while thinning, downsizing and low noise are required. There is a strong demand for it.

[0003] A conventional motor will be described below. As shown in FIG. 2, the hub 1 is supported by the shaft 2. The shaft 2 is inserted into the bearing hole of the sleeve 3, and the thrust plate 4 is installed so as to face the end surface of the shaft 2. The sleeve 3 is a bracket 5
The core 6 is supported by the bracket 5. The rotor frame 7 is supported by the hub 1, and the magnet 8 is installed on the inner circumference of the rotor frame 7 so as to face the core 6.

[0004]

[Problems to be solved by the invention]

(1) In the motor as in the conventional example, the joining portion between the hub 1 and the rotor frame 7 is not sufficiently taken, and the joining portion has a low strength, so that the joining portion causes a vibration source when the motor body is driven. Therefore, the noise of the motor body may increase.

The present invention solves the above problems, and an object thereof is to provide a low noise motor.

(2) In the conventional motor, the rotor frame 7 is cut out from the member by cutting.
Therefore, it takes time to manufacture the rotor frame 7, the number of steps is increased, and unnecessary cost is generated only for the member to be cut out because the rotor frame 7 is cut out from the member. As a result, The production cost of the rotor frame might increase.

The present invention solves the above problems, and an object of the present invention is to provide a rotor frame for a motor which is inexpensive to manufacture.

(3) Since the shaft 2 is inserted into the bearing hole of the sleeve 3 in the motor as in the conventional example, there is a risk that the shaft 2 will fall out of the bearing hole against external force such as vibration and shock. there were.

The present invention solves the above problems, and an object of the present invention is to provide a motor in which the rotor does not fall out.

[0010]

[Means for Solving the Problems]

(1) In order to achieve the above-mentioned object (1), the present invention is characterized in that the rotor frame is bent at the joint portion between the rotor frame and the hub so as to follow the inner peripheral surface of the hub. Have.

(2) In order to achieve the above object (2), the present invention is characterized in that the rotor frame is manufactured by punching a plate material by press working.

(3) In order to achieve the above object (3), the present invention is characterized in that the inner diameter portion of the rotor frame is bent in a direction perpendicular to the shaft.

[0013]

Therefore, according to the present invention, first, the rotor frame 7 shown in FIG. 2 is bent so as to be along the inner peripheral surface of the hub 1 so that the joint portion between the hub 1 and the rotor frame 7 is formed. Increase the strength of the joint.
As a result, there is no possibility that the joint portion becomes a vibration source when the motor is driven due to insufficient strength, and the noise of the motor body can be reduced.

Secondly, the method of manufacturing the rotor frame 7 will be described.
By changing from shaving by cutting to punching by pressing, it is possible to shorten the manufacturing time of the rotor frame 7 and to eliminate the cost of unnecessary members consumed by shaving. As a result, the manufacturing cost of the rotor frame can be reduced.

Thirdly, the inner diameter portion of the rotor frame 7 joined along the inner peripheral surface of the hub 1 is bent in the direction perpendicular to the shaft 2. As a result,
When an external force is applied to the motor body, the retaining member provided on the sleeve 3 comes into contact with the inner diameter portion of the rotor frame 7 that has been subjected to bending, so that the rotor can be prevented from coming off from the bearing. .

[0016]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the hub 1 is supported by a shaft 2. The sleeve 3 is provided with a threaded portion 3 a, and the shaft 2 is inserted into a bearing hole of the sleeve 3. A thrust plate 4 is installed so as to face the end surface of the shaft 2. The sleeve 3 is supported by the bracket 5, and the core 6 is attached to the bracket 5.
It is supported by being crimped by. The rotor frame 7 is supported by the hub 1, and the magnet 8 is installed on the inner circumference of the rotor frame 7 so as to face the core 6. The retaining member 9 is provided with a threaded portion 9a, which is fixed to the threaded portion 3a of the sleeve 3 by screwing.

The operation of the above structure will be described below. First, since the rotor frame 7 is bent along the inner peripheral surface of the hub 1, the hub 1
And the strength of the joint portion of the rotor frame 7 increases. As a result, when the motor is driven, the joint portion does not become a vibration source due to insufficient strength, and the noise of the motor body can be reduced.

Secondly, since the rotor frame 7 is manufactured by punching by press working, it is possible to shorten the manufacturing time and to eliminate the member cost consumed by shaving. As a result, the manufacturing cost of the rotor frame 7 can be reduced, so that the price of the motor body can be reduced.

Thirdly, in order to prevent the shaft 2 from coming off from the sleeve 3, a bending process is applied to the inner diameter portion of the rotor frame 7 in a direction perpendicular to the shaft 2, so that the rotating body vibrates or receives an impact. It will not fall out due to the external force, and the motor will be able to rotate stably.

Further, the outer diameter of the rotor frame 7 is set to be at least twice the diameter of the portion of the hub 1 on which the magnetic disk is mounted. As a result, it becomes possible to obtain a sufficient drive torque for driving the rotating body of the motor body, and the motor body can be made thinner in the axial direction. here,
A method of incorporating the retaining member 9 will be briefly described. The retaining member 9 is attached when the shaft 2 of the rotating body is inserted into the sleeve 3. The retaining member 9
Is passed through the shaft 2 of the rotating body while being inclined with respect to the shaft 2, and the convex portion of the retaining member 9 is inserted into the inner peripheral concave portion formed by the inner diameter portions of the hub 1 and the rotor frame 7. Next, the center of the retaining member 9 and the shaft 2
The shaft 2 is inserted into the sleeve 3 with their centers aligned. The sleeve 3 and the retaining member 9 have a threaded portion, and the retaining member 9 is screwed and fastened to the sleeve 3 by the threaded portion 9a.

[0022]

As described above, according to the present invention, since the number of joints between the hub and the rotor frame is increased and the strength of the joints is increased, the vibration source at the time of driving the motor is eliminated.
The noise of the motor body can be reduced.

Secondly, since the rotor frame is manufactured by punching by press working, it is possible to shorten the manufacturing time and to eliminate the cost of members consumed by cutting, and as a result, the manufacturing cost of the rotor frame is reduced. Since the price is low, the price of the motor body can be reduced.

Thirdly, in order to prevent the shaft from coming off the sleeve, the inner diameter portion of the rotor frame is bent in a direction perpendicular to the shaft,
It is possible to realize a motor in which the rotating body does not fall off due to external forces such as vibration and shock.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an internal configuration of a motor according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing the internal structure of a conventional motor.

[Explanation of symbols]

 1 hub 2 shaft 3 sleeve 3a, 9a screw part 4 thrust plate 5 bracket 6 core 7 rotor frame 8 magnet 9 retaining member

Claims (3)

[Claims] 1. A bracket main body, a hub that rotates relative to the bracket main body, a rotor frame supported by an inner peripheral surface of the hub, a shaft supporting the hub, and a shaft supporting the shaft. A sleeve, a thrust plate installed to face the end face of the shaft, a shaft, the sleeve, and a thrust plate that form a fluid bearing. The rotor frame is arranged along the inner peripheral surface of the hub. A brushless motor characterized in that the joint part of is bent. 2. The brushless motor according to claim 1, wherein the rotor frame is manufactured by stamping a member by press working. 3. A bracket main body, a hub which rotates relative to the bracket main body, a rotor frame supported by an inner peripheral surface of the hub, a shaft supporting the hub, and the shaft. A sleeve, a thrust plate installed to face the end face of the shaft, a retaining member for preventing the rotating body installed in the sleeve from coming off, the shaft, the sleeve and the thrust plate to form a fluid bearing. In the configuration, the inner diameter portion of the rotor frame installed along the inner peripheral surface of the hub is bent in a direction perpendicular to the axis, and when the external force acts on the motor main body, the detachment occurs. The stopper member prevents the rotating body from coming off the bearing by contacting the bent inner diameter portion of the rotor frame. Resumota.