JPS63209446A - Bearing mechanism for motor - Google Patents

Abstract

PURPOSE:To easily suppress the inclination and backlash of a shaft, by inserting an O ring into a space between an internal molding section in contact with the rotor shaft of the internal ring of a rolling bearing, and the internal molding section in contact with the rotor shaft of a prepressure ring. CONSTITUTION:By an O ring 10, prepressure is applied to a rolling bearing 5, and so to transfer the stress of a spring 8 to the rolling bearing 5, the ring 10 is inserted into a shaft 4 in front of a prepressure ring 7 inserted into the shaft 4. The O ring 10 is determined with the almost same inner diameter as the outer diameter of the shaft 4, and so the spring pressure of the prepressure spring 8 is applied to the rolling bearing 5 and the O ring 10. Accordingly, the shaft 4 is always held by the O ring 10, and a clearance between the shaft 4 and the rolling bearing 5 is compensated for.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a bearing mechanism for a motor using a rolling bearing, and is used in office automation equipment, information equipment, etc. that require high-precision motor rotation.

BACKGROUND OF THE INVENTION Recently, the use of OA and %tn information equipment has been increasing, especially because of the high reliability of brushless morphs.

Examples include spindle motors for polygon mirror scanners such as C91-Beam 1/Interface, optical discs, and video discs. All of these motors are required to have high rotational precision and high mechanical precision such as shaft deflection and inclination.

Particularly; 1', the motor for the ribbon mirror scanner rotates at high speed, and the inclination of the shaft affects the positional accuracy of the polygon mirror, and the printing accuracy of the rate-to-beam printer is affected by n'L. It is an extremely important technology to suppress vibration and tilt.

FIG. 3 shows the structure of a brushless motor for a polygon mirror scanner. The outer rings of the pair of rolling bearings 5 are fixed to the housing 1 by adhesive or shrink fitting,
A starter shaft 4 is inserted into the inner ring of the rolling bearing 5, and a preload is applied to the rolling bearing 5 by a preload spring 8 via a preload ring 7. At this time, the preload boss 9
The amount of compression of the spring 8 is determined and fixed so that the preload becomes a certain constant value.

In addition, in FIG. 3, 2 is a rotating body attached to the shaft 4, 3 is a magnet rotor attached to the rotating body 2, and 6 is a stator provided opposite to the magnet rotor 3.

Problems to be Solved by the Invention In the above configuration, when a preload is applied to the rolling bearing 5, the movement of the shaft 4 in the axial thrust direction is suppressed, but a clearance is inevitably created between the shaft 4 and the rolling bearing 5. exists in If there is no clearance,
Each part (housing 1° shaft 4. rolling bearing 5)
If the vertical center position of the rolling bearing 5 deviates even slightly due to variations in dimensional tolerance, the shaft 4 may not be able to be inserted. This clearance is rotor 2
The shaft 4 may run out while the rotor 2 is rotating.
If a force is applied to the shaft 4 for some reason, the shaft 4 will also be tilted.

As a method for removing the clearance, No. 411
As shown in the enlarged view of the main part in N, there is a method in which the outer diameter of the shaft 4 and the inner diameter of the rolling bearing 5 are selectively fitted to make the clearance as small as possible.
A method of gluing 4a has been considered, but both methods involve a lot of work loss, and the work itself is complicated, which increases the number of manufacturing steps.

The present invention has been made in order to eliminate the drawbacks of the above-mentioned conventional techniques, and does not cause any work loss, is easy to work with, and suppresses the inclination and rattling of the shaft.

, Means for Solving the Problems Therefore, the present invention provides an O-ring in the space formed by the chamfered part of the inner ring of the rolling bearing that contacts the rotor shaft and the chamfered part of the inner surface of the preload ring that contacts the rotor shaft. This is what was inserted.

If there is a clearance between the working shaft, the foot, and the rolling bearing, the shaft will move freely by that clearance, and this movement will manifest itself as a tilt of the shaft or a runout during rotation. According to the present invention, by inserting the O-ring, the O-ring simultaneously presses the inner ring of the rolling bearing and the shaft, and it is possible to suppress movement by the clearance between the shaft and the inner ring of the bearing.

Example 1 and 2 show the bearing structure of the present invention.

The O-ring 10 is connected to the shaft 4 in order to transmit the stress of the spring 8 to the rolling bearing 5 in order to apply a preload to the rolling bearing 5.
The spring pressure of the preload spring 8 is applied to the rolling bearing 5 and the O-ring 10 because the preload spring 8 is inserted into the shaft 4 before the preload ring 7 which is inserted into the shaft 4, and the inner diameter is determined to be approximately the same as the outer diameter of the shaft 4.

That is, the O-ring 10 is inserted into a space formed by an inner chamfer of the inner ring of the rolling bearing 5 that contacts the rotor shaft 4 and an inner chamfer of the preload ring 7 that contacts the shaft 4. Therefore, the shaft 4 is always held down by the O-ring 12, and the shaft 4 is held down by the rolling bearing 5.
Clearance with? It is a form of compensation.

According to the present invention, the material of the O-ring 12 is preferably a rubber-based material having elasticity in view of the function of the O-ring described above, and its cross section is circular, triangular, square, etc. as long as the above-mentioned function is satisfied. Both are valid.

By adopting the bearing structure of the present invention, the effects of the invention are as follows.
The extremely easy process of inserting an O-ring, without the tedious process of selective fitting or adhesion, which is required in the past, can prevent backlash and damage to the rotor shaft.
This is extremely effective in meeting the demands for precision in OA, information equipment, etc.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing an embodiment of the bearing structure of the present invention, Figure 2 is a sectional view showing an embodiment of the bearing structure of the present invention.
The figure is an exploded perspective view showing the assembly procedure of the bearing structure of the present invention.
FIG. 3 is a sectional view of a brushless smoke for a polygon mirror scanner, and FIG. 4 is a sectional view of a conventional example of a bearing mechanism. DESCRIPTION OF SYMBOLS 1... Housing, 4... Rotor shaft, 5... Rolling bearing, 7... Preload ring, 8... Preload spring, 10・・・・・・
0 ring. 4---D-ta shaft 5---2 r) r'),! 11I! ÷7---Children link'' Section T Figure 8
□ - Child, pressure 11" Figure 2 Figure 8 M

Claims (1)

[Claims] In a motor bearing mechanism in which a preload is applied by a preload spring via a preload ring to a rolling bearing in which an outer ring is fixed to a motor housing and a rotor shaft is inserted and held in the inner ring, a preload is applied by a preload spring through a preload ring. A motor bearing mechanism in which an O-ring is inserted to fill the space formed by the chamfered inner surface and the chamfered inner surface of the preload ring that contacts the rotor shaft.