JP2915878B2 - 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 provided with a hemispherical bearing having an improved communication means for preventing pressure from being concentrated between two opposing hemispherical bearings. About.

[0002]

2. Description of the Related Art Generally, hemispherical bearings support a rotating shaft rotatably 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 provided between contact surfaces. Since it does not require an agent, it is used for internal motors of electronic products such as hard disks of computers, laser scanners, laser printers, etc., which require miniaturization.

[0003] The laser printer among these is a printer of a system using a laser beam for printing, and a scanned image is formed on a photosensitive drum which 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 showing the internal structure of such a conventional rotary polygon mirror device. As shown in FIG. 1, the rotary polygon mirror device 10 is mounted on a photosensitive drum (not shown). A polygon mirror 11 that reflects light, a motor 20 that rotates while supporting the polygon mirror, and a cover 12 that receives the polygon mirror 11 and the motor 20 are provided. The polygon mirror 11 reflects light rays through a hole 12a formed in the cover 12. The motor 20 includes a stator 21 and a rotor 22 that interact electromagnetically. The stator 21 includes a stator frame 21a and a stator coil 21 wound therearound.
b. Further, the rotor 22 includes a rotor bush 22.
a and a rotor magnet 22b installed on the outer peripheral surface. The polygon mirror 11 is provided above the rotor bush 22a.
The polygon mirror 11 rotates with the rotor bush 22a, and upper and lower hemispherical bearings 24a and 24b rotatably support the upper and lower portions of the rotor bush 22a. Inserted. These hemispherical bearings 24a and 24b are fixed to a support shaft 23 which is vertically installed at the center of the stator frame 21a, and are arranged such that their curved portions face each other.

FIG. 2 is a cross-sectional view showing the structure of a conventional support shaft provided with communication means and a hemispherical bearing. FIG. 3 is a sectional view showing a conventional support shaft provided with communication means and a spacer connected thereto. FIG. As shown in these figures, the upper and lower sides of the rotor bush 22a have hemispherical grooves 25a, 25b formed in a hemispherical shape so as to receive the hemispherical bearings 24a, 24b, and the hemispherical grooves 25a, 25b.
A communication hole 26 is formed so that the communication holes 5b communicate with each other. Such upper and lower hemispherical grooves 25a, 25b
Are respectively provided with hemispherical bearings 24a, 24b, and formed therein with coupling holes 27, 27 'into which the support shaft 23 can be inserted. The outer peripheral surfaces of the hemispherical bearings 24a and 24b are provided on the rotor bush 2.
A large number of spiral grooves 19 (see FIG. 1) are formed between the rotor bush 22a and the hemispherical bearings 24a, 24b so that air flows in between the rotor bush 22a and the hemispherical bearings 24a and 24b to smooth the rotation.

A spacer 30 for adjusting the clearance between the hemispherical bearings 24a, 24b and the rotor bush 22a is provided between the upper and lower hemispherical bearings 24a, 24b.
Are connected to the support shaft 23, and a spacer groove 31 which falls into the spacer 30 is formed on both sides of the spacer 30.

As shown in FIG. 3, the outer peripheral surface of the support shaft 23 is provided with a circumferential groove 41 and a communicating means 42 formed in a direction perpendicular to the circumferential groove. More specifically, when the spacer 30 is coupled to the support shaft 23,
A circumferential groove 41 having a predetermined depth is formed in the outer circumferential surface of the support shaft 23 which comes into contact with the spacer groove 31 in the circumferential direction so that the hemispherical bearings 24a and 24b are formed when the rotor bush 22a rotates. And the air flowing between the hemispherical grooves 25a and 25b collects in the circumferential groove 41 through the spacer groove 31. As a result, the pressure due to the air that has flowed in concentrates around the spacer groove 31, which causes unstable operation of the rotary polygon mirror device due to such excessive pressure. In order to solve this, a communication means 42 is provided on the support shaft 23 for communicating the inside of the rotor bush 22a with the outside of the rotary polygon mirror device.
Is formed by axially cutting a part of the outer peripheral surface of the support shaft 23 from the lower end of the support shaft 23 to the circumferential groove 41.

[0008] The rotating polygon mirror device 10 constructed as described above.
In the state where power is not applied, the lower hemispherical bearing 24b
And the lower hemispherical groove 25b are maintained in contact with each other, and the upper hemispherical bearing 24a and the upper hemispherical groove 25a are maintained in a separated state. In this state, when power is applied and the rotor bush 22a starts rotating, air flows between the hemispherical bearings 24a, 24b and the rotor bush 22a, and the inflowing air flows into the hemispherical bearings 24a, 24b. The maximum pressure distribution is made in the minimum gap formed by the eccentric coupling between the rotor bush 22a and the rotor bush 22a, and the hemispherical bearings 24a, 24b and the rotor bush 22a are separated from each other at a fine interval. 22a floats upward. On this occasion,
The air that has flowed into the rotor bush 22a is supplied to the adjacent spacers 3 of the upper and lower hemispherical bearings 24a and 24b.
The pressure concentrates at the zero portion, and the concentrated pressure is reduced to the same atmospheric pressure as the external pressure by the ventilation passage 42 communicating with the outside, while the rotation due to excessive pressure in the rotor bush 22a. The unstable operation of the polygon mirror device is prevented.

[0009]

However, in the conventional motor configured as described above, the communicating means is formed by cutting the outer peripheral surface of the support shaft inserted into the hemispherical bearing. When the communication means is formed large because the operation of the communication means is performed smoothly, the precision of the connection between the support shaft and the hemispherical bearing is reduced. Was not satisfied at the same time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to form a communication means inside a support shaft so that the size of the communication means is sufficiently ensured and the support shaft and the support shaft are connected to each other. An object of the present invention is to provide a motor having a hemispherical bearing that can increase the precision of coupling with the hemispherical bearing.

[0011]

According to the present invention, there is provided a motor having a hemispherical bearing according to the present invention, wherein the rotor bush has upper and lower hemispherical grooves communicating with each other, and the rotor bush is received in the hemispherical grooves. Upper and lower hemispherical bearings, a support shaft penetrating the inside of the upper and lower hemispherical bearings and having a circumferential groove in the circumferential direction, and the upper and lower hemispherical bearings interposed between the upper and lower hemispherical bearings. And a spacer for adjusting the clearance between the hemispherical groove,
Flow between the rotor bush and the hemispherical bearing
In order to maintain the pressure of the incoming air properly,
An axial center is formed at the center of the inside of the shaft, and one end of the shaft is
A communicating means comprising a first vent communicating with the outside of the support shaft, and a second vent formed so as to communicate the first vent and the circumferential groove in a direction perpendicular to the first vent; , Is provided.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a hemispherical bearing communication device according to a preferred embodiment of the present invention. FIG. 4 is a cross-sectional view showing the structure of a support shaft having communication means and a hemispherical bearing according to the present invention, and FIG. 5 shows a support shaft having communication means according to the present invention and a spacer coupled thereto. It is a perspective view. As shown in these drawings, the upper and lower sides of the rotor bush 122a have hemispherical grooves 125a, 1a formed in a hemispherical shape so as to receive hemispherical bearings 124a, 124b.
25b and a communication hole 126 formed such that the hemispherical grooves 125a and 125b communicate with each other. The upper and lower hemispherical grooves 125a and 125b receive hemispherical bearings 124a and 124b, respectively, and have coupling holes 127 and 127 'into which the support shaft 123 can be inserted. further,
The outer peripheral surfaces of the hemispherical bearings 124a and 124b are attached to the rotor bush 122a when the rotor bush 122a rotates.
A number of spiral grooves 19 (see FIG. 1) are formed between the first and second hemispherical bearings 124a and 124b so that air flows in and smooth rotation.

Upper and lower hemispherical bearings 124a, 124
b, a spacer 130 for adjusting the clearance between the hemispherical bearings 124a, 124b and the rotor bush 122a is connected to the support shaft 123, and the spacer 13
0 has spacer grooves 131 formed on both sides thereof.

As shown in FIG. 5, a circumferential groove 141 is formed on the outer peripheral surface of the support shaft 123 in the radial direction, and a communication means 142 is provided on the inner center in the axial direction. It is formed so as to communicate with the groove 141. More specifically, when the spacer 130 is coupled to the support shaft 123, the support shaft 1 comes into contact with the spacer groove 131.
A circumferential groove 141 having a predetermined depth is formed in the outer circumferential surface of the rotor bush 122a.
The air flowing between the hemispherical bearings 124a, 124b and the hemispherical grooves 125a, 125b at the time of rotation is collected in the circumferential groove 141 through the spacer groove 131.
As a result, the pressure due to the air that has flowed in concentrates around the spacer groove 131, causing unstable operation of the rotary polygon mirror device due to such excessive pressure. In order to solve this, a communication means 142 for communicating the inside of the rotor bush 122a with the outside of the rotary polygon mirror device is provided inside the support shaft 123, and this communication means 14 is provided.
Reference numeral 2 denotes a first ventilation hole 142 formed axially in an inner central portion from the lower end of the support shaft 123 to the same height as the circumferential groove 141.
a and the first ventilation port 14a in a direction perpendicular to the first ventilation port 142a.
2a and a second ventilation hole 142b formed so as to communicate the circumferential groove 141.

In the rotary polygon mirror device thus constructed, the lower hemispherical bearing 124b is provided by the weight of the rotor bush 122a when no power is applied.
And the lower hemispherical groove 125b are maintained in contact with each other, and the upper hemispherical bearing 124a and the upper hemispherical groove 125a are maintained in a separated state. In this state, when power is applied and the rotor bush 122a starts rotating, the hemispherical bearings 124a and 124b and the rotor bush 1
22a, and flows into the hemispherical bearings 124a, 124b and the rotor bush 12a.
2a, a maximum pressure distribution is made in the minimum gap formed by the eccentric coupling, so that the hemispherical bearings 124a, 1a
24b and the rotor bush 122a are spaced apart from each other with a minute gap, so that the rotor bush 122a floats upward. At this time, the air flowing into the rotor bush 122a causes the upper and lower hemispherical bearings 1 to rotate.
The pressure concentrates around the spacer groove 131 of the spacer 130 adjacent to the spacers 24a and 124b, and the concentrated pressure is reduced to the same atmospheric pressure state as the external pressure by the ventilation path (communication means) 142. However, unstable operation of the rotary polygon mirror device due to excessive pressure in the rotor bush 122a is prevented.

[0016]

As described above, in the motor having the hemispherical bearing according to the present invention, instead of cutting off the outer peripheral surface of the support shaft inserted into the hemispherical bearing, the communicating means is used.
By forming it inside, it is possible to secure a sufficient size of the communication means for smoothly performing the above-described operation, and it is possible to increase the precision of coupling between the support shaft and the hemispherical bearing. There are advantages.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an internal structure of a rotary polygon mirror device in which a conventional motor is installed.

FIG. 2 is a cross-sectional view showing the structure of a conventional support shaft provided with a communication means and a hemispherical bearing.

FIG. 3 is a perspective view of a support shaft and a spacer provided with a conventional communication means.

FIG. 4 is a sectional view showing the structure of a support shaft and a hemispherical bearing provided with communication means according to the present invention.

FIG. 5 is a perspective view of a support shaft and a spacer provided with communication means according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 rotating polygon mirror device 11 polygon mirror 12 cover 12a hole 13 polygon mirror bracket 19 groove 20 motor 21 stator 21a stator frame 21b stator coil 22 rotor 22a rotor bush 22b rotor magnet 23 support shaft 24a upper hemispherical bearing 24b Lower hemispherical bearing 25a Upper hemispherical groove 25b Lower hemispherical groove 26 Communication hole 27 Connection hole 27 'Connection hole 30 Spacer 31 Spacer groove 41 Circumferential groove 42 Communication means 122a Rotor bush 123 Support shaft 124a Upper hemispherical bearing 124b Lower hemispherical bearing 125a Upper hemispherical groove 125b Lower hemispherical groove 126 Communication hole 127 Connection hole 127 'Connection hole 130 Spacer 131 Spacer groove 141 Circumferential groove 142 Communication means 142a First ventilation port 142b Second communication Mood

Claims (1)

(57) [Claims] 1. A rotor bush having upper and lower hemispherical grooves communicating with each other, upper and lower hemispherical bearings respectively received in the hemispherical grooves, and circumferentially penetrating inside the upper and lower hemispherical bearings. A support shaft having a circumferential groove, a spacer that is provided between the upper and lower hemispherical bearings and adjusts a clearance between the upper and lower hemispherical bearings and the hemispherical groove, and the rotor bush and the hemispherical bearing. Flow between
In order to maintain the pressure of the incoming air properly,
An axial center is formed at the center of the inside of the shaft, and one end of the shaft is
A first vent communicating with the outside of the support shaft;
Inside the first vent and vertically in front of the first vent
A second vent formed so as to communicate with the circumferential groove;
And a communication means comprising : a motor having a hemispherical bearing.