JPS6032547A - Exhaust gas cooling fan of rotary electric machine - Google Patents

Abstract

PURPOSE:To improve the efficiency of a rotary electric machine by using a shape memory alloy for blades of an exhaust gas cooling fan of the machine and varying the shape of the blades by the temperature change. CONSTITUTION:In a rotary electric machine of a load state in which an exhaust gas cooling fan 11 having blades 10 of shape memory alloy, cooling air intaken from a suction window 7 of a bearing bracket 9a is led to a cooling fan 4a of a rotor 5 by an air guide plate 6a. When becoming a light load state, the temperature in the machine decreases, and the temperature decreases lower than the temperature of the shape variation of the shape memory alloy. Then, the blade 10b is bent in a zigzag shape at the center of the blade 10b, the outer diameter of the cooling fan is reduced to increase the radial distance to a guide plate 6b, and small air flow rate adapted for the light load state can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an exhaust cooling fan for a rotating electric machine whose blades are made of a shape memory alloy.

[Technical background of the invention and its problems]

In general, fans play an important role in cooling rotating electric machines, and the cooling effect is improved by increasing the fan's air volume C2. The air volume of this fan is expressed by the following formula 1% (1) where ψ: Flow coefficient B: Inside of the fan blade (in) D: Outside diameter of the fan (in) U: Outside circumferential speed of the fan (m/5ec) -ηDN 0X100 N: Fan rotation speed (rpm) The larger the fan blade 1J, fan outer diameter, and fan rotation speed, the greater the air volume, but the windage loss increases and the efficiency of the rotating electric machine decreases.

Generally, the temperature of a rotating electric machine during operation changes due to changes in efficiency and rotational speed depending on the load condition.

For this reason, if a fan is provided to sufficiently cool the rotating electrical machine when it is operating at a high temperature, an extra air volume will be provided when the rotating electrical machine is operating at a low temperature, resulting in more cooling than necessary. Therefore, the rotating electrical machine in the low temperature operating state loses excess energy. On the other hand, if a fan is provided that is optimal at low temperature operating conditions, there is a drawback that cooling will be insufficient at high temperatures.

[Purpose of the invention]

The present invention improves on the above points, and uses shape memory alloy (i14) in the blades of the exhaust cooling fan, which changes the shape of the blades depending on the temperature of the rotating electric machine load state and generates the optimum air volume. The purpose is to provide an exhaust cooling fan.

[Summary of the invention]

The present invention is an exhaust cooling fan for a rotating electric machine, the fan having blades made of a shape memory alloy. As a result, the temperature at which the blade shape changes is set, and the blade shape is changed by the temperature change caused by the load of the rotating electric machine. Then, an exhaust cooling fan with a shape suitable for the cooling place is obtained, and an air volume optimal for the load condition of the rotating electric machine is generated.

Therefore, the efficiency of the rotating electric machine is improved by eliminating the unnecessary air flow in the conventional light load state, and at the same time, it is possible to prevent temperature rise beyond the allowable level during low speed rotation.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a front view of the top f1 (including a cross section) of a rotating electric machine in a loaded state, showing an embodiment of the present invention;
A stator core 3 containing stator windings 2 is delivered inside the stator core 3. A rotor 5 having die-cast cooling fans 4a and 4b is disposed on the inner diameter of the stator core 3 via a gap.

Further, bearing brackets (9a and 9b) having an intake window 7 and an exhaust window 8 are disposed through four wind plates 6a and 6b on the load side and anti-load side provided at both ends of the frame 1, and the rotor 5 is mounted on a bearing bracket. Supported through.

The blade 10 made of shape memory alloy is fixed to the fan boss with rivets or bolts, etc. as shown in FIG. 3 (a).
) as shown in the rotor 5.
Fix it on the anti-load side.

This shape memory alloy has bidirectional 'J' i -N i
For alloy systems, the temperature at which the shape changes is, for example, 70°C for class E insulation.
The set temperature is set at about ゛C, and this set temperature is changed depending on the insulation class.

In a loaded rotary electric machine that has a built-in exhaust cooling fan 11 having blades 10 made of shape memory alloy, the cooling air sucked in from the intake window 7 of the bearing bracket 9a is It goes up the plate 6al2 and is guided to the cooling fan 4a of the rotor 5. Then, the cooling air processed by the rotation of the rotor 5 flows from the ventilation path between the coil end and the air guide plate 63 to the ventilation path between the stator core 3 and the frame 1 as shown by the arrow. flows to Then, it flows over the surface of the coil end and is discharged from the exhaust window 8 of the bearing bracket 9b by the exhaust cooling fan 11.

Since the temperature inside the rotating electric machine under such a load condition is higher than the temperature at which the shape memory alloy changes its shape, the bellows-like bent portion of the shape memory alloy blade in the low temperature condition extends in the radial direction. Then, as shown in FIG. 3(a), the outer diameter of the exhaust cooling fan becomes maximum, and the rotation of the exhaust cooling fan provides the maximum amount of air, thereby providing a cooling function under load.

- When the actual diameter load condition is reached, the temperature inside the rotating electrical machine decreases,
This temperature is lower than the temperature at which the shape memory alloy changes shape. Then, the blade 10b bends in a bellows shape at the center of the blade 10b as shown in FIG. 3(b), and the outer diameter of the exhaust cooling fan decreases as shown in FIG. The distance is also increased, resulting in a smaller air volume suitable for light load conditions. Therefore, the conventional phenomenon of wind loss being the same in light load states and load states is eliminated, and the wind loss in light load states is reduced compared to that in loaded states, improving the efficiency of the rotating electric machine.

As another example, a primary voltage controlled rotary tube 1,
During high-speed rotation, the rotational speed is high, so the exhaust cooling fan provides sufficient airflow and sufficient cooling is performed, but during low-speed rotation, the airflow l'11 decreases as the rotational speed decreases, resulting in poor cooling. In such a case, the blade shape should be bent (+11 in the radial direction or circumferential direction as shown in FIGS. S4 (a) to (d)) during high-speed rotation.

Then, since the outer diameter of the exhaust cooling fan is small or the area is small, the air volume is small compared to the blade shape of the bent 7 (υ).Then, as the rotation speed becomes low, the internal temperature of the rotating electric machine reaches its upper limit. , when the blade reaches the temperature above the shape change,
The bent portions of the blades are extended, increasing the outer diameter and surface finish of the exhaust cooling fan. Therefore, despite the low speed rotation, a wind n tip close to the wind h1 obtained at high speed rotation can be obtained, and the rotating electrical machine can be sufficiently cooled even during low speed rotation, eliminating the risk of the temperature exceeding the permissible temperature.

〔Effect of the invention〕

As described above, according to the present invention, a shape memory alloy is used for the blades of a single-turn electric exhaust cooling fan, the temperature at which the blade shape changes is set, and the blade shape is changed by the temperature change due to the load of the rotating electric machine. change. Then, an exhaust cooling fan with a shape suitable for the cooling place is obtained, and an air volume optimal for the load condition of rotating heavy machinery is generated. Therefore, the efficiency of the rotating electric machine can be improved by eliminating unnecessary air volume in the conventional light load state, and it is also possible to prevent an increase in temperature during low speed rotation.

[Brief explanation of the drawing]

FIG. 1 is a front view including an upper section of a rotating electrical machine in a loaded state showing an embodiment of the present invention; FIG. The figure is a side sectional view of the exhaust cooling fan of the present invention, and FIG. 4 is a side view of the exhaust cooling fan showing another embodiment. 10...Blade, 11...Exhaust cooling fan. Agent Patent attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 3 (α) Figure 3<b) (0-) (C) Figure 4 (b) CIt)

Claims (1)

[Claims] What is claimed is: 1. A cooling fan for exhaust air of a rotating electric machine, the fan having blades made of a shape memory alloy.