JP2872203B2 - Motor with hemispherical bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor, and more particularly, to a motor in which two opposing hemispherical bearings and an adjacent hemispherical bush are provided with permanent magnets to reduce the axial load. The present invention relates to a motor having a hemispherical bearing.

[0002]

2. Description of the Related Art In general, hemispherical bearings allow a rotating shaft to be rotatably supported in a radial direction and an axial direction, so that it is not necessary to use a plurality of bearings for each direction, and special lubrication is required between contact surfaces. Since it does not require an agent, it is used for an internal motor of an electronic product such as a hard disk of a computer, a laser scanner, a laser printer, or the like, which is required to be downsized.

[0003] Among these, a laser printer is a printer of a system that prints using a laser beam, and a scanned image is formed on a photosensitive drum that responds to light by the laser beam. For this purpose, a rotary polygon mirror device having a polygon mirror that rotates so as to move the light beam at a constant linear speed so as to coincide with the axial direction of the photosensitive drum is provided.

FIG. 1 is a view schematically showing a configuration of a general laser printer. As shown in the figure, a laser printer is provided with a semiconductor laser 1 according to scanned data.
A collimator lens 102 for collecting the light of No. 01 into a parallel laser beam, a rotating polygon mirror device 100 for forming a linear image with the parallel light beam, and a rotating polygon mirror device 100. A cylindrical lens 103 provided between the collimating lens 102 and the collimating lens 102;

Further, there is provided a photosensitive drum 104 which is a medium for recording a print information pattern using a light beam emitted from the cylindrical lens 103 through the rotary polygon mirror device 100.
Between the rotary polygon mirror device 100 and the photosensitive drum 104, a spherical lens 105, an annular lens 106, a horizontal synchronization mirror 107, a detection sensor 108, a reflection mirror 109, and the like are sequentially arranged. A light beam moved at a constant linear speed toward the photosensitive drum 104 by the rotating polygon mirror device 100 is focused on the photosensitive drum 104 via the spherical lens 105, and the light beam is moved to a desired position on the photosensitive drum 104 by the reflecting mirror 109. Is reflected. The horizontal synchronization mirror 107 and the detection sensor 108 are used to match the start positions on the photosensitive drum 104.

FIG. 2 is a view showing the internal structure of a conventional rotary polygon mirror device. As shown in FIG.
00 is a polygon mirror 111 for reflecting light rays to the photosensitive drum.
And a motor 120 that supports and rotates the motor, and a polygonal mirror 111 and a housing 112 that receives the motor 120.

The polygon mirror 111 reflects a light beam through a hole 112a formed in the housing 112. The motor 120 is an electromagnetically interacting stator 12
1 and a rotor 125, and a stator 121 made of a coil is fixed to a housing 112,
The rotator 125 is connected to a fixing member 113 provided below the polygon mirror 111.

A hemispherical bush 122 is connected to the center of the housing 112, and upper and lower hemispherical bearings 124a and 124b are rotatably inserted into upper and lower portions of the hemispherical bush 122.

Upper and lower hemispherical bearings 124a,
A rotation shaft 123 is provided at the center of the hemispherical bush 122 and connected to the polygon mirror 111 so as to penetrate them, and a rotor 125 provided above the stator 121 when power is applied. And a polygon mirror 11 coupled thereto
1 and the rotating shaft 123 rotate integrally. Thus, the hemispherical bearing 1 coupled to the rotating shaft 123
24a and 124b also start to rotate, but air flows in by a groove 119 provided outside the hemispherical bearings 124a and 124b, and the hemispherical bush 122
Contact surface is separated at a fine interval.

Next, the structure of a conventional hemispherical bearing and a hemispherical bush will be described in detail with reference to FIG. The hemispherical bearings 12 are provided above and below the hemispherical bush 122.
4a, 124b so that hemispherical grooves 126a,
26b are formed, and these hemispherical grooves 12
A communication hole 127 is formed so that 6a and 126b communicate with each other. Upper and lower hemispherical grooves 126a, 126
b, hemispherical bearings 124a and 124b are arranged such that the respective flat portions 131a and 131b face each other, and a coupling hole (not shown) into which the rotating shaft 123 can be inserted is formed therein. A spiral groove 119 is formed on the outside.

When power is applied to the rotary polygon mirror device 100, the rotor 125 rotates, thereby rotating the polygon mirror 111, the rotating shaft 123, and the hemispherical bearings 124a and 124b. . When the hemispherical bearings 124a, 124b start to rotate, the hemispherical bearings 124a, 124b and the hemispherical bush 122
And air flows in between the hemispherical bearings 124a,
The maximum pressure distribution is made in the minimum gap formed by the eccentric coupling between the hemispherical bush 122 and the hemispherical bearing 124a, 124b and the hemispherical groove 126a, 12
6b is separated at a fine interval.

[0012]

However, in the conventional rotary polygon mirror device configured as described above,
When power is not applied, the upper hemispherical bearing and the upper hemispherical groove are kept in contact with each other due to the weight of the rotor, the fixing member, the polygon mirror, the rotating shaft, and the rotating body composed of the hemispherical bearing. . Therefore, there is a problem that the hemispherical bearing and the hemispherical bush receive a load in the axial direction due to the weight of the rotating body.

Further, at the time of initial startup or at the time of stop after startup, there is a problem that friction occurs due to the contact between the hemispherical bearing and the hemispherical bush, which increases current consumption of the motor and causes wear of the contact surface. .

The present invention has been made to solve the above problems, and an object of the present invention is to provide a separation means between a hemispherical bearing and a hemispherical bush for maintaining them in a non-contact state. An object of the present invention is to provide a motor having a hemispherical bearing capable of reducing an axial load acting on the hemispherical bearing and the hemispherical bush.

[0015]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a hemispherical bush having hemispherical grooves communicating with each other at upper and lower portions, a hemispherical bearing received in the hemispherical grooves, and a hemispherical bearing. In a motor having a rotating shaft penetrating the inside of a bearing, a plurality of permanent magnets are arranged in a row so that repulsive force acts on adjacent surfaces of opposed upper and lower hemispherical bearings and a hemispherical bush located therebetween. It is characterized by being arranged.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a hemispherical bearing according to the present invention will be described in more detail with reference to the accompanying drawings. The same parts as those in the related art will be described using the same reference numerals.

FIG. 4 is a sectional view showing the internal structure of a rotary polygon mirror device provided with a motor according to the present invention. As shown in the drawing, the rotating polygon mirror device 100 includes a polygon mirror 111 for reflecting light rays on a photosensitive drum, a motor 120 for supporting and rotating the same, and a housing 112 for receiving the polygon mirror 111 and the motor 120. And

The polygon mirror 111 reflects light rays through a hole 112a formed in the housing 112. The motor 120 is an electromagnetically interacting stator 12
1 and a rotor 125, and a stator 121 made of a coil is fixed to a housing 112,
The rotator 125 is connected to a fixing member 113 provided below the polygon mirror 111.

A hemispherical bush 122 is connected to the center of the housing 112, and upper and lower hemispherical bearings 124a and 124b are rotatably inserted into upper and lower portions of the hemispherical bush 122.

Upper and lower hemispherical bearings 124a,
A rotating shaft 123 is provided at the center of the hemispherical bush 122 and connected to the polygon mirror 111 so that the rotating shaft 123 is provided above the stator 121 when power is applied. , Polygon mirror 111, rotation axis 123,
In addition, the rotating body including the hemispherical bearings 124a and 124b starts to rotate integrally. When the hemispherical bearings 124a, 124b start rotating, air flows between the hemispherical bearings 124a, 124b and the hemispherical bush 122, and the hemispherical bearings 124a, 124b.
4b and the hemispherical bush 122, a maximum gap is formed in the minimum gap formed by the eccentric coupling, so that the hemispherical bearings 124a, 124b and the hemispherical grooves 126a, 126a,
26b.

FIG. 5 is a sectional view showing the structure of a hemispherical bearing and a hemispherical bush according to the present invention, which will be described in more detail with reference to FIG. Hemispherical grooves 126a, 126b are formed on the upper and lower sides of the hemispherical bush 122 so as to receive the hemispherical bearings 124a, 124b,
A communication hole 127 is formed at the center so that the hemispherical grooves 126a and 126b communicate with each other. In the upper and lower hemispherical grooves 126a, 126b, hemispherical bearings 124a, 124b are provided with respective flat portions 131a, 1b.
31b are arranged so as to face each other, a coupling hole (not shown) into which the rotating shaft 123 can be inserted is formed inside, and a spiral groove 119 is formed outside.

As shown in FIG. 6, the characteristic elements of the present invention include upper and lower hemispherical bearings 124a,
A permanent magnet is provided on each of the opposed flat portions 131a and 131b of the 124b, and another one of the two permanent magnets 140a and 140c provided above and below is connected to the hemispherical bush 122 between the two permanent magnets 140a and 140c. Permanent magnet 14
0b is provided. At this time, the three permanent magnets are arranged one above the other so that repulsive forces are generated.

The rotating polygon mirror device 10 constructed as described above
At 0, in the initial state with no power applied,
The hemispherical bearing 1 is formed by the repulsive force of the permanent magnet as described above.
24a and 124b and the hemispherical grooves 126a and 126b are kept apart from each other, so that power is applied to the rotor 125 and the polygon mirror 1 provided above the stator 121.
11, a rotating shaft 123, and a hemispherical bearing 124a,
When the rotating body made of 124b rotates, smoother rotation is performed.

[0024]

As described above, the motor having the upper and lower hemispherical bearings according to the present invention is provided on the adjacent surfaces of the opposing upper and lower hemispherical bearings and the hemispherical bush located between them. By providing the permanent magnets so that repulsive forces act on each other, the hemispherical bearing and the hemispherical groove are separated from each other to reduce the axial load acting on the hemispherical bearing and the hemispherical bush due to the weight of the rotating body. Can be done.

Another advantage is that current consumption and wear are reduced by minimizing friction between the hemispherical bearing and the hemispherical bush at the time of initial start-up and at the time of stop after start-up.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view schematically showing a configuration of a general laser printer.

FIG. 2 is a sectional view showing an internal structure of a rotary polygon mirror device provided with a conventional motor.

FIG. 3 is a cross-sectional view showing a structure of a conventional hemispherical bearing and a hemispherical bush.

FIG. 4 is a sectional view showing an internal structure of a rotary polygon mirror device provided with a motor according to the present invention.

FIG. 5 is a sectional view showing a structure of a hemispherical bearing and a hemispherical bush according to the present invention.

FIG. 6 is an enlarged view of an “X” part in FIG. 5;

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 rotating polygon mirror device 101 semiconductor laser 102 collimating lens 103 cylindrical lens 104 photosensitive drum 105 spherical lens 106 toric lens 107 horizontal synchronous mirror 108 detection sensor 109 reflecting mirror 111 polygon mirror 112 housing 112a hole 113 fixing member 119 groove 120 motor 121 Stator 122 Hemispherical bush 123 Rotation axis 124a Upper hemispherical bearing 124b Lower hemispherical bearing 125 Rotor 126a Upper hemispherical groove 126b Lower hemispherical groove 127 Communication hole 140a Permanent magnet 140b Permanent magnet 140c Permanent magnet

Claims (3)

(57) [Claims] 1. A motor comprising: a hemispherical bush having upper and lower hemispherical grooves communicating with each other; a hemispherical bearing received in the hemispherical groove; and a rotating shaft penetrating inside the hemispherical bearing. A motor having a hemispherical bearing, further comprising a separating means for maintaining the hemispherical bearing and the hemispherical bush in a non-contact state. 2. The device according to claim 1, wherein said separating means comprises a plurality of permanent magnets provided on adjacent surfaces of the upper and lower hemispherical bearings facing each other and a hemispherical bush located therebetween. Motor with hemispherical bearings. 3. The permanent magnets according to claim 2, wherein the permanent magnets are arranged in a row so that repulsive forces act on each other.
A motor comprising a hemispherical bearing according to claim 1.