JPH0715329Y2 - Rotating electric machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a rotary electric machine using an aluminum die-cast rotor, in which a balance correction balancer is mounted on a rotary shaft.

(Prior Art) FIG. 3 shows a cross section of a rotary electric machine using a balancer in the prior art. Normally, the balance correction of the rotor is carried out by adding a balance weight to the balance pin 2 integrally formed by aluminum die-casting on both end faces of the rotor 1, but the balance weight is accompanied by the increase in speed of the rotating electric machine. Since the centrifugal force generated in the balance pin becomes large, and as a result, the stress generated in the balance pin 2 becomes large, there is a limit to the balance correction by the increasing method.

In order to deal with this, there is a method of mounting the balancer 3 on both ends of the rotor on the rotor shaft 4 at the both ends of the rotor as shown in FIG. .

In such a structure, as shown in FIG.
A space 6 surrounded by 1, the winding 5 and the balancer 3 is formed. Since it is difficult for the air in the space 6 to exchange heat with the outside, the cooling effect of the rotor deteriorates. As a result, the rotor temperature rises significantly, and the temperature of the winding also rises due to this effect. FIG. 4 is a cross section of an open self-ventilating rotary electric machine having a structure in which the pressure difference of the outer diameter of the blades generated by the rotation of the rotor blades 7 is utilized to take in air through a ventilation window 9 provided in the bearing bracket 8 for ventilation. It is a figure.

When the above-mentioned balancer 3 is attached in this structure,
Since the blade effect of the rotor blade 7 is greatly reduced due to the influence of the balancer, sufficient intake from the ventilation window 9 is not performed, which causes a temperature rise due to the reduction of the cooling air volume.

SUMMARY OF THE INVENTION The present invention is an improvement of the above problems, and provides a rotating electric machine having a balancer for correcting rotor balance, which can reduce the temperature rise of the rotor and windings and can be applied to an open self-ventilated rotating electric machine. To aim for things.

[Structure of the Invention] (Means for Solving the Problem) The present invention is a rotating electric machine using a conventional aluminum die-cast rotor, which has a balance correction of a small outer diameter of 80 to 50% of the inner diameter of the rotor blade. (EN) A rotary electric machine having a balance correction structure capable of improving a heat radiation effect of a rotor or a winding and reacting to an open self-ventilation type rotary electric machine by using a balancer.

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

FIG. 1 shows a cross section of an open self-ventilated rotary electric machine using a small-diameter disk-shaped balancer, which is an embodiment of the present invention.

Reference numeral 1 is a rotor, and 7 is a rotor blade integrally formed by aluminum die casting. The rotor 1 is fitted on the shaft 4 and is rotatably supported by the bearing 14 mounted on the bearing bracket 8. The outer diameter d of the small-diameter balancer 3a is set to 80% or less of the inner diameter of the rotor blade, and the rotor blade of the shaft 4 and the bearing are mounted by shrink fitting. An air rectifying plate 10 is attached to the inner surface of the bearing bracket 8, and the tip of the air rectifying plate 10 is located slightly away from the outer peripheral end of the rotor blade 7. Ventilation passages 13 for cooling air between the frame 12 and the stator core 11
Is provided.

The operation of the rotating electric machine using the small-diameter balancer configured as described above will be described.

When the rotor 1 rotates, the rotor blades 7 also rotate with the rotor. As a result, due to the pressure difference generated on the outer and inner circumferences of the rotor blades 7, the cooling air is sucked through the ventilation window 9 and enters the rotating electric machine along the ventilation plate 10. This cooling air passes through the ventilation passage between the ventilation plate 10 and the small-diameter balancer 3a, passes along the inner and outer surfaces of the winding 5 by the rotor blades 7, and reaches the ventilation passage 13 between the stator core 11 and the frame 12.

FIG. 2 is a cooling air flow rate change diagram when the outer diameter d of the small diameter balancer 3a is changed in the 2-pole 1.5kW open drip-proof three-phase induction motor.

As a result of the experiment, it was confirmed that when the ratio (d / D) of the outer diameter d of the small diameter balancer 3a and the inner diameter D of the rotor blade 7 was 0.8 to 0.5, there was no influence of the cooling air flow reduction due to the balancer mounting.

In this way, the outer diameter d of the small diameter balancer 3a is set to the inner diameter D of the rotor blade.
By setting 80 to 50% of the above, the cooling air passage is sufficiently secured, and the balancer, which has been seen when using a conventional large-diameter balancer, does not obstruct the passage of the cooling air. There is no decrease.

Further, since the balance correction is performed by reducing the balancer, it is possible to prevent an increase in the stress of the balance pin portion due to the increase in the rotation speed, which is seen in the conventional increase method of adding the balance weight to the balance pin portion.

As is clear from the above description, by reducing the outer diameter of the conventional balancer to 0.8 to 0.5 smaller than the inner diameter of the rotor blade, the blade effect of the rotor blade does not decrease and the cooling effect deteriorates. A balancer can be installed without the need for a coil, and the cooling air flow is reduced as in the conventional structure.
It is possible to suppress an increase in temperature of the rotor, bearing, etc.

On the other hand, in an experiment using a 4-pole, 22-kW fully-closed three-phase induction motor, the winding temperature was measured using the conventional large-diameter balancer and the small-diameter balancer (d / D = 1) based on the present invention. It was confirmed that the temperature decreased by 12 ° C for the increase. From this fact as well, it was confirmed that the use of the small-diameter balancer not only in the open self-ventilated rotary electric machine but also in the fully closed rotary electric machine promotes the stirring of the inside air by the rotor blades.

[Effects of the Invention] As is clear from the above description, the rotating electric machine according to the present invention uses a small-diameter balancer having an outer diameter as small as 80 to 50% of the inner diameter of the rotor blades, so that the cooling air volume is completely reduced. Reduces the temperature rise of windings, bearings, and rotors without decreasing
It enables weight reduction using a balancer, and enables higher speed and smaller size of the rotating electric machine.

Further, also in the fully-closed rotary electric machine, the increase in the effect of stirring the inside air due to the use of the small diameter balancer exerts a remarkable effect in reducing the winding temperature.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an open type rotating electric machine showing an embodiment of the present invention, FIG. 2 is a flow rate change diagram of the rotating electric machine according to the present invention, and FIG. 3 is a sectional view of a conventional open type rotating electric machine. FIG. 4 is a cross-sectional view of a conventional open self-ventilated rotary electric machine. 1 …… Rotor, 2 …… Balance pin, 3 …… Large diameter balancer, 3
a …… Small diameter balancer, 4 …… Axis, 6 …… Space, 7 …… Rotor blade, 10 …… Ventilation plate, 11 …… Stator core.

Claims (2)

[Scope of utility model registration request] 1. A bearing bracket having a plurality of ventilation windows fitted to both ends of a frame, and a conical shape having an opening at the tip, and a bottom portion fixedly arranged to the bearing bracket and cooled by suction from the ventilation window. A rotary electric machine having a ventilation plate for guiding wind, an aluminum die-cast rotor having a plurality of rotor blades formed by aluminum die-casting, and a disc-shaped balancer mounted on a rotor shaft, The opening diameter at the tip of the ventilation plate is set to be approximately the same as the outer diameter of the rotor blade, and the ventilation plate is mounted on the bearing bracket with the tip close to the axial tip of the rotor blade. 80 ~ of the inner diameter of the rotor blade mounted on the rotor shaft on the radial direction line
A rotating electric machine, comprising a balancer having an outer diameter of 50%, wherein cooling air that has passed through the ventilation plate from a ventilation window of a bearing bracket is supplied to the rotor blades between the balancer outer diameter and the ventilation plate inner diameter. 2. A machine comprising a stator, an aluminum die-cast rotor having a plurality of rotor blades formed by aluminum die-casting, and a disc-shaped balancer mounted on a rotor shaft. In the closed rotating electric machine, a balancer having an outer diameter equal to the inner diameter of the rotor blade is attached to the rotor shaft so as to be close to the axial tip of the rotor blade.