JPS6219088Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a rotating electrical machine that reduces noise.

As shown in FIG. 1, a conventional rotating electric machine blows cooling air 3 that cools the heat generating parts housed in the yoke 1 through a plurality of exhaust holes 2 provided at the outer peripheral end of the yoke 1. It is designed for direct exhaust. For this reason, the magnetic noise and mechanical noise of the rotating machine are also discharged all at once, resulting in a drawback that the noise is large.

This invention was made to eliminate the above-mentioned drawbacks, and provides a rotating electric machine in which an air passage is provided on the outer periphery of the yoke to cover each exhaust hole and make the radial cross section of the rotating electric machine approximately square.

A rotating electrical machine generally has a circular or polygonal cross section in the radial direction, and a substantially rectangular space is secured at its mounting position. The inventor focused on these points and achieved the desired purpose by providing a wind duct around the outer circumference of the yoke so that the cross section in the radial direction of the rotating electric machine was approximately square.

This will be explained below based on the figures. Figures 2 and 3
In the figure, 1 is a yoke, 2 is an exhaust hole, and a plurality of them are provided at the outer peripheral end of the yoke 1. Reference numeral 4 denotes a wind duct which is closed at both ends and formed into a predetermined shape, and is attached to the yoke 1 so as to cover each exhaust hole 2. 5 is a sound absorbing material pasted on the inner surface of each air passage 4, and 6 is an exhaust port provided in each air passage 4.

With this structure, the yoke 1 and each air passage 4 form a radial cross section of the yoke into a substantially rectangular shape, and the cooling air 7a containing noise is directed as shown by the arrow. As shown, the cooling air 7a discharged from the exhaust hole 2 in the radial direction changes its direction in the axial direction when it hits the sound absorbing material 5, and then changes its direction in the radial direction again when it hits the sound absorbing material 5 at the end of the air passage 4. The air is then discharged from the exhaust port 6 into the atmosphere as cooling air 7 with reduced noise.

It is generally known that noise energy is absorbed when it collides with an object, and that the noise level decreases as the energy decreases.

FIG. 4 is a curve diagram showing the relationship between the number of rotations of the electric motor and noise according to a noise measurement test, in which numeral 3 shows the noise characteristics of the conventional rotating electric machine and 7 shows the noise characteristics of the example. According to this, the invented one has a rotation speed of 4,000 r.
A noise reduction of approximately 5dB(A)at1m was achieved at pm.

In the above embodiment, the case where the exhaust port of the air passage was provided in the radial direction of the yoke was explained, but the same effect as in the above embodiment can be obtained even if the exhaust port is provided in the axial direction.
Noise can be further reduced by making the sound absorbing material thicker or by providing a predetermined partition member inside the wind duct.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional rotating electrical machine, FIG. 2 is a perspective view of a proposed rotating electrical machine, FIG. 3 is a sectional view of FIG. 2, and FIG. 4 is a curve diagram of noise characteristics. In the figure, 1 is a yoke, 2 is an exhaust hole, 4 is a wind passage, and 5
is a sound absorbing material, 6 is an exhaust port, and 7 is a cooling air. Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] A rotating body fixed to a rotating shaft is placed inside a yoke,
A plurality of cooling air discharge ports are provided on the outer periphery of the yoke in a direction substantially perpendicular to the rotation axis, and a projected cross section surrounding the discharge ports and in a direction substantially perpendicular to the rotation axis extends through the yoke. The air outlet is configured to have a substantially rectangular shape including the exhaust port, and has an exhaust port communicating with the inside of the yoke via the discharge port at a predetermined distance in the direction of the rotating shaft from the surface facing the discharge port. A rotating electric machine characterized in that a sound-absorbing material that can come into contact with the cooling air is installed inside the machine.