JPH0421337A - Electric motor - Google Patents

Abstract

PURPOSE:To form a highly reliable hearing by forming knurl-like recessing and projecting parts to the end section of a shaft forcibly fitted in a rotator and deciding the outside diameter by grinding the projecting parts and, at the same time, putting a bearing on the recessing and projecting parts after filling the recessing parts with a heat insulating member. CONSTITUTION:This electric motor is formed in such a way that knurl-like recessing and projecting parts 4 are formed at the end section of a shaft 2 and the parts 4 are formed to an outside diameter suitable for a bearing 3 to be put on the parts 4 by grinding the tips of the projecting parts 5. The recessing parts 6 are filled with a heat insulating member 7 made of a resin, etc. When the heat of a rotor 1 is transferred to the end section where the bearing 3 is put on the shaft 2, the heat of the shaft 2 is not transferred to the inner race of the beraing 3, because the heat insulating member 7 in the gap between the bearing 3 and parts 4 exerts a strong resistance. Therefore, the service life of the bearing 3 can be prolonged and a highly reliable electric motor can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric motor equipped with a bearing structure that is not affected by the heat of the rotor.

[Prior Art] In an electric motor, heat of a rotor is transmitted to a bearing through a shaft, and since the bearing is provided in a bracket, there may be a large temperature gradient between the heat dissipated by the bracket and the bearing.

This temperature gradient is caused by a large temperature gradient between the inner and outer rings when the bearing is formed by a ball bearing, which compresses the balls interposed between the inner and outer rings due to thermal expansion. It turns out.

In addition, rising temperatures have led to lubricating oil being released.

When the bearing is a metal type, an oil core is generally provided on the outside in the radial direction, or heat is transmitted to the oil core to increase the temperature of the lubricating oil.

[Problems to be Solved by the Invention] When heat is conducted to the bearing in this way, if the former ball is compressed, the ball will be damaged or damaged.
This shortens the life of the bearing.

Of course, if the temperature of the lubricating oil rises, it will evaporate.
Scratches formed on the ball, causing noise and shortening its lifespan.

In particular, the bearings of electric motors that drive fans of air conditioners etc. have low I
Since high noise is required, failure of the bearing due to such scratches on the ball is inconvenient because the slight noise of the bearing is diffused through the fan.

In addition, in the case of the latter metal type, the temperature of the lubricating oil in the oil core increases, which promotes evaporation of the lubricating oil, which also has the problem of shortening its life.

The present invention was made in view of these circumstances, and
It is an object of the present invention to provide an electric motor that can eliminate bearing failures due to bearing temperature gradients and form highly reliable bearings.

[Means for Solving the Problems] The present invention involves forming knurling-like unevenness on the end of the shaft that is press-fitted to the rotor, and determining the outer diameter by grinding the convex portions of the unevenness. The problem is solved by filling the recess with a heat insulating material and fitting the bearing into the recess.

[Operation] Since the heat insulating member is interposed while the heat of the rotor is transferred to the bearing via the shaft, it exhibits thermal resistance and the rate of temperature rise on the inner diameter side of the bearing is reduced.

Therefore, even if the outer diameter side of the bearing is cooled by the bracket, a large temperature gradient will not occur.

[Embodiment] The present invention will be explained based on an embodiment shown in the drawings. Fig. 1 is a vertical cross-sectional view of a main part of an electric motor according to an embodiment of the present invention, and Fig. 2 is a side view of the motor. It is a diagram.

In FIG. 1, the electric motor has a rotor 1 formed to rotate inside a stator (not shown), and a shaft 2 that is press-fitted into the rotor 1.

The shaft 2 is provided at its end with a bearing 3 formed by a ball bearing, and this bearing 3 is fitted into a knurled unevenness 4 formed at the end of the shaft 2.

Furthermore, this unevenness 4 is located on the outside in the radial direction, that is, the convex portion 5
The tip of the shaft 2 is cut, and the axis of the cut surface coincides with the axis of the shaft 2.

Further, the recesses 6 of the unevenness 4 are filled with a heat insulating material 7 such as resin or adhesive.

In FIG. 2, the electric motor is fitted with a bearing 3 consisting of four ball bearings formed at the end of a shaft 2. Because the bearing 3 is fitted, the tips of the convex parts of the convexes and convexes 4 are fitted. A heat insulating member 7 such as resin is filled in the position of the recess 5 of the unevenness 4, and the inner ring of the bearing 3 is configured to stably support the end of the shaft 2. .

In such a configuration, the electric motor has a funnel l, ? at the end of the shaft 2. A --shaped unevenness 4 is formed, and the tips of the convex parts 5 of the unevenness 4 are cut to have an outer diameter that allows the bearing 2 to fit therein.

Then, the recess 6 is filled with a heat insulating member 7 such as resin, but the end point may be filled in a step before cutting the projection 5 and cut together with the projection 5.

Further, when using an adhesive, the bearing 3 may be fitted into the unevenness 4 and then the recessed portion 6 may be filled.

With this configuration, when the heat of the rotor 1 is transmitted through the shaft 2 to the end where the bearing 3 is provided, the bearing 3
Since the heat insulating member 7 is interposed between the surface and the unevenness 4, it exhibits a large resistance and is thermally insulated, so that the heat of the shaft 2 is not transmitted to the inner ring of the bearing 3.

Of course, the heat of the shaft 2 is transmitted to the bearing 3 via the convex portion 5, but since this type of bearing 3 is held by a member with good heat dissipation such as a bracket (not shown), the heat conduction from the shaft 3 is limited. As more heat is dissipated, the temperature rise of the bearing 3 is reduced.

Even if a metal bearing is used for the bearing, this effect reduces heat conduction from the shaft 2, eliminating problems such as evaporation of lubricating oil, and providing the same effect on life extension. 6 The bearing 3 can be used due to the mechanical strength of the protrusion 5 if the recess 6 of the unevenness 4 is not filled with the heat insulating member 7, but if the unevenness 4 is rolled like knurling, Since it becomes difficult to make the convex part 5 larger by deepening the concave part 6, the mechanical strength of the convex part 5 decreases.
It is preferable that the heat insulating member 7 be filled in the space.

As the heat insulating member 7, a premix made of a resin and an inert substance such as sand, a resin without a mixture, or a typical adhesive can be used.

If adhesive is used, it can be expected that it will have an adhesive effect on the inner ring of the bearing 3, so there is no need to press fit the bearing 3 into the unevenness 4. Also, if the recessed part 6 is filled with a premix, etc., it will adhere to the inner ring of the bearing 3. Since it comes into contact with the inner ring of the bearing 3, the mechanical strength is increased and the bearing 3 can be press-fitted.

[Advantageous Effects of the Invention 1] According to the present invention, since heat is not conducted to the bearing through the shaft, the life of the bearing is extended and a highly reliable electric motor can be obtained, and the effects are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part of an electric motor according to an embodiment of the present invention, and FIG. 2 is a side view thereof. 1...2 rotor, 2...shaft, 3...-bearing,
4... Unevenness, 5... Convex part, 6... Concave part, 7
...Insulating material.

Claims (1)

[Claims] A knurling-like unevenness is formed on the end of the shaft that is press-fitted into the rotor, and the outer diameter is determined by grinding the protrusions of the unevenness, and the recess is filled with a heat insulating material, and the bearing is installed in the unevenness. An electric motor characterized by being fitted.