JPS6370822A - Polygon motor - Google Patents

Abstract

PURPOSE:To make the titled polygon mirror small in size and light in weight by forming a dynamic pressure air bearing by a mirror surface of a polygon mirror and a wall surface which is placed so as to be opposed to said surface. CONSTITUTION:A shaft 1 is pressed into a housing 2 and fixed, and a coil 4 for generating a rotating magnetic field is provided on the shaft 1. In the periphery of its coil, a polygon mirror 3 whose inner wall surface is magnetized, and which forms a rotor of a motor is provided. A window 6 is a window for allowing a laser to go in and out. By a mirror surface 3A of the polygon mirror, which is rounded a corner formed by the mirror surface and the mirror surface, and a housing inner wall surface 2A which is placed so as to be opposed to said surface, a dynamic pressure air bearing is formed and a load in the radial direction is received, and on the bottom part of the polygon mirror, a groove for generating a dynamic pressure is provided, forms a dynamic pressure air bearing with a housing inner wall surface 2B and receives a load in the thrust direction. In such a way, since the bearing is formed by utilizing the polygon mirror, the titled polygon motor can be made small in size and light in weight.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a polygon motor.

2. Description of the Related Art In recent years, polygon motors have been required to be smaller and lighter as laser printers become smaller.

An example of the conventional polygon motor mentioned above will be described below with reference to the drawings.

FIG. 3 shows a longitudinal section of a conventional polygon motor. In FIG. 3, a fixed shaft 12 is press-fitted into the motor housing bottom 13, a rotor 14 is rotatably inserted into the fixed shaft 12, and a polygon mirror 1 is inserted into the rotor 14.
7 is fixed. 15 is a coil for generating a rotating magnetic field, and a portion 14A of the rotor facing the coil 15
is magnetized, and the rotor 14 forming the rotor of the motor is rotated by the magnetic field generated in the coil 15.

The operation of the polygon motor configured as described above will be explained below. First, the rotor 14 is rotated by a rotating magnetic field generated by the coil 15. When rotor 14 rotates, group 12A and group 13
The rotor 14 floats due to the pressure generated by A, is supported in the radial direction and the thrust direction, and can support the polygon mirror at high speed.

Problems to be Solved by the Invention In the polygon motor constructed as described above, since the polygon mirror and the bearing are constructed separately, there is a limit to miniaturization and thinning, and there are also problems in mass production.

The present invention solves the above conventional drawbacks in view of the above problems, and has a configuration that allows the polygon motor to be made much smaller and thinner than the conventional polygon motor in which a polygon mirror and a bearing are provided separately. It is a polygon motor.

Means for Solving the Problems In order to solve the above problems, the polygon motor of the present invention includes a polygon mirror in which all corners formed by the mirror surfaces are rounded, and a polygon mirror facing the mirror surface of the polygon mirror. This eliminates the need for air for configuring the wall surface separately from the arrangement, making it possible to significantly reduce the size and weight.

EXAMPLE Hereinafter, a polygon motor according to an example of the present invention will be described with reference to FIG.

FIG. 1 shows the configuration of a polygon motor in a first embodiment of the present invention. In FIG. 1, a shaft 1 is press-fitted into a housing 2, and a coil 4 for generating a rotating magnetic field is provided on the shaft 1. A polygon mirror 3 whose inner wall surface is magnetized and forms the rotor of the motor is provided around it. The window 6 is a window for entering and exiting the laser.

Next, the bearing part, which is the key point of the present invention, will be explained. The mirror surface 3A of the polygon mirror with rounded corners formed by the mirror surfaces and the inner wall surface 2A of the housing placed opposite thereto form a dynamic pressure air bearing and receive a load in the radial direction. is provided with a group for generating dynamic pressure, which forms a dynamic pressure air bearing with the housing inner wall surface 2B and receives a load in the thrust direction.

Since the bearing is formed using polygon mirrors in this manner, it is possible to make the bearing significantly smaller and lighter than before.

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

FIG. 2 is a sectional view of a polygon motor showing a second embodiment of the present invention.

In the figure, a dynamic pressure air bearing is formed by a housing inner wall surface 7A placed opposite to the mirror surface of the polygon mirror 8, and receives loads in the radial direction.

Further, a group for generating dynamic pressure is provided at the bottom of the polygon mirror, forming a dynamic pressure bearing with the housing inner wall surface 3B to receive a load in the thrust direction. The above configuration is similar to the configuration shown in FIG.

The difference from the configuration shown in FIG. 1 is that the bottom of the polygon mirror is magnetized and a rotating magnetic field coil 9 is provided facing it to form a planar opposed type motor. This makes it possible to make the polygon motor thinner.

Effects of the Invention As described above, the present invention can be made much smaller and lighter than conventional polygon motors by forming a dynamic pressure air bearing with the mirror surface of the polygon mirror and the wall surface facing it. can.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a polygon motor according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a polygon motor according to a first embodiment of the present invention, and FIG. 3 is a longitudinal cross-section of a conventional polygon motor. It is a front view. 2...Housing, 2 people...Inner wall of housing, 3...Polygon mirror, 3A...
... polygon mirror surface, 7 ... housing,
7A...Housing inner wall surface, 8...Polygon mirror, 8A...Polygon mirror surface, 1
2A...Group (for radial support), 13A
...Group (for thrust support), 17...
...Polygon mirror. Name of agent: Patent attorney Toshio Nakao 1 person 3A2. −
Bosogon mirror surface Figure 2

Claims (1)

[Claims] a polygon mirror; a wall surface disposed opposite to the mirror surface of the polygon mirror, the polygon mirror;
A polygon motor characterized in that a radial air bearing is formed by the wall surface.