JPH025664Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to a brushless motor suitable as a drive motor for VTRs, floppy disk drives, etc., and particularly relates to the structure of a bearing that rotatably supports the rotating shaft of a rotor. Regarding.

[Traditional background]

BACKGROUND ART Conventionally, brushless motors have been widely used as drive motors for VTRs, floppy disk drives, and the like because they are compact and can provide high torque.

3 and 4 show an outline of a conventional brushless motor. Here, FIG. 3 is a sectional view showing the overall configuration of the brushless motor, and FIG. 4 is an enlarged sectional view showing details of the bearing portion of the brushless motor of FIG. 3.

The brushless motor is composed of a rotor section 1 and a stator section 2, as shown in FIG. A boss 13 is fixed to the rotor part 1 by screws to the central axis of a rotor yoke 3 formed in a circular bowl shape.
A rotary shaft 4 is fixedly fixed to this boss 13,
A rotor magnet 5 is fixed inside the rotor yoke 3 with the rotating shaft 4 as its center, and is formed into a ring shape and magnetized in segments along the circumferential direction.
Further, in the stator section 2, a bearing boss 7 is fixed to a stator yoke 6 formed of a soft magnetic material, and a bearing boss 7 is located at a position facing the rotor magnet 5 with the boss 7 as the center. A plurality of drive coils 8 are arranged in a circular manner. As shown in FIG. 4, in the central shaft portion of the boss 7, a bearing hole 10 has a bearing hole 10 formed approximately in the center thereof with a bearing 9 having a height approximately equal to the width of the outer ring of a rolling bearing (to be described later) and protruding inward. A rolling bearing 11, such as a ball bearing, is installed in the bearing hole 10 below the bearing 9, and a sliding bearing 12, such as an oil-less metal, is press-fitted into the upper part of the bearing 9. has been done.

By supporting the rotating shaft 4 erected in the rotor section 1 on the inner surface of the inner ring of the rolling bearing 11 and the inner surface of the sliding bearing 12, the rotor section 1 can be freely rotated with respect to the stator 2. It can be configured as follows.

By the way, the inner diameter of the bearing hole 10 into which the rolling bearing 11 is installed is formed to be somewhat larger than the outer diameter of the rolling bearing 11 in order to facilitate its insertion. The axis is aligned with the sliding bearing 12 using a tool, and the bearing is fixed with adhesive under a predetermined preload.

However, adjustment using such a special jig differs from the state in which the actual shaft 4 and rotor part 1 are assembled, and when the actual items are assembled, misalignment may occur, and especially due to differences in preload conditions. This will affect the rotation.

[Purpose of invention]

The present invention was devised to eliminate the drawbacks of the prior art described above, and is a brushless motor that can be implemented at low cost and that uses preload to prevent performance deterioration after the rotor and shaft are assembled. The purpose is to provide.

[Summary of the idea]

In order to achieve the above object, the present invention fixes the rotating shaft to a first boss fixed to the rotor yoke of the rotor, and a sliding bearing is attached to the inner periphery of the second boss fixed to the stator part. In a brushless motor that includes a sliding bearing and rotatably supports the rotating shaft by these bearings, a relief part is formed in the sliding bearing to avoid contact with the inner ring of the rolling bearing, and the rolling bearing is A gap for filling an adhesive is formed between an outer periphery and an inner periphery of the second boss, and a hole for inserting an adhesive is formed in the rotor yoke and the first boss at a position facing the gap. They are characterized by their respective formations.

[Example of idea]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a sectional view showing the present invention, in which the same members as in the conventional example are designated by the same reference numerals.

A bearing hole 15 having a constant diameter from the upper surface to the lower surface of the boss 7 is formed in the central axis portion of the boss 7 . A rolling bearing 1 is provided on the inner periphery of the sliding bearing 12 on the side that comes into contact with the rolling bearing 11.
A relief portion 12a is formed to avoid the inner ring portion of the inner ring 1. Further, the outer diameter of the rolling bearing 11 is formed to be smaller than the bearing hole 15 so that it can be filled with adhesive.

In the brushless motor of this embodiment, the relief portion 12a is formed in the slide bearing 12 to prevent direct contact between the slide bearing 12 and the inner ring portion of the rolling bearing 11. Problems such as seizure will not occur even if a bearing receiver is not provided.

On the other hand, a hole 16 for inserting an adhesive is formed near the rotation axis 4 of the rotor yoke 3, and this hole 1
A hole 17 is also bored in the boss 13 at a position corresponding to 6.

The present invention is constructed as described above, and its installation work will be explained below.

As shown in FIG. 1, the rotor yoke 3 and the rotating shaft 4 are assembled into the rolling bearing 11, and then from the holes 16 and 17 of the rotor yoke 3 and the boss 13,
The outer peripheral surface of the rolling bearing 11 and the bearing hole 15 of the boss 7
Fill adhesive between the inner peripheral surface and fix.

At this time, in order to eliminate play between the outer ring and the inner ring of the rolling bearing 11, in this embodiment, a preload is applied by the adhesion force of the rotor magnet 5. In other words, the preload is maintained when the product is completed. It is designed to be fixed so that misalignment does not occur.

If an adhesive with a long curing time is used, the rotor can be installed after the adhesive is applied, and alignment can be performed by percussion.

Note that the present invention is not limited to the above embodiments, and the holes may be plural or round or square.

[Effect of idea]

As explained above, the brushless motor of the present invention has an adhesive insertion hole in the rotor, etc., so even if the preload state is different from the conventional brushless motor, alignment can be performed when it is assembled into a product. It can be fixed in place without causing misalignment.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
1, FIG. 3 is a sectional view showing the overall structure of a brushless motor to which the present invention is applied, and FIG. 4 is a sectional view showing the bearing structure of a conventional brushless motor. DESCRIPTION OF SYMBOLS 1...Rotor part, 2...Stator part, 3...Rotor yoke, 4...Rotating shaft, 5...Rotor magnet, 6...Stator yoke, 7...Boss, 8...
Drive coil, 9... Bearing bearing, 10... Bearing hole, 11... Rolling bearing, 12... Sliding bearing, 13... Boss, 15... Bearing hole, 16, 17
...hole.

Claims (1)

[Scope of utility model registration request] The first rotor yoke 3 of the rotor section 1 is
A rotating shaft 4 is fixed to a boss 13 of
Rolling bearings 11 are installed internally, and these bearings 1
In the brushless motor in which the rotary shaft 4 is rotatably supported by 1 and 12, the sliding bearing 12 is formed with a relief portion 12a to avoid contact with the inner ring of the rolling bearing 11, and the outer periphery of the rolling bearing 11 is and the inner periphery of the second boss 7 to form an adhesive filling gap, and the rotor yoke 3 and the first
A brushless motor characterized in that holes 16 and 17 for inserting an adhesive are formed in the boss 13 of the motor.