JPS5813192A - Electric fan - Google Patents

Abstract

PURPOSE:To simplify construction by slipping a motor shaft with respect to an input shaft, in a wind direction grill speed reduction mechanism, when the input shaft is subjected to a load torque over a normal operation torque so as to reduce the load torque, thereby permitting a gear, a bearing, a supporting frame and so on. to be reduced the strength. CONSTITUTION:When a permanent magnet 14 mounted on an output shaft 8 of a speed reduction mechanism 7 is opposed to a magnetic substance 15 secured to a revolution shaft 4B of a motor with a voides 16A, 16B, a magnetic circuit is formed. When the motor runs, the magnetic substance 15 and the permanent magnet 14 are magnetically attracted into one form and the revolution torque of the motor is thereby transmitted to the speed reduction mechanism 7. Once the load torque exceeds a preset transmission torque, a joint slips and acts as a toque restricting joint. Hence, by setting the load of the speed reduction mechanism 7 to the minimum, the load torque is eased and the demanded strength of a gear, a bearing, a supporting frame and so on may be thereby reduced, on account of which the weight and size of the entire speed reduction mechanism may be reduced.

Description

[Detailed Description of the Invention] In a conventional electric fan equipped with a wind direction grill for changing the direction of the wind radially through rotation, the rotating shaft of the fan motor is connected to the input shaft of the speed reduction mechanism for rotating the wind direction grill. It was directly connected.

The configuration is illustrated in FIG.
is a motor rotating shaft to which an impeller 5 of an electric fan is directly connected to one end, and 7 is a speed reduction mechanism. A rotary wind direction grill 9 is directly connected to the output shaft 8 of the speed reduction mechanism, and its input shaft is directly connected to the other end of the motor rotation shaft 4.

Normally, the rotation of the wind direction grill is approximately 5 rpm, so the reduction ratio is approximately 1 for the motor rotation of 120 Or pm.
/240.

However, since the wind generated by the impeller 5 has a rotational component, it imparts rotational force to the wind direction grill.

The magnitude of this rotational force is determined by the impeller 5 and the wind direction grill 9.
Although it differs depending on the shape of the grill, it was found that the torque required to rotate the grill is 70 to 80 inches.

Therefore, the torque of the motor for driving the wind direction grill may be small enough to compensate for the torque generated by the air blowing.

However, when starting the motor, in addition to the inertial resistance of the wind direction grille and the starting frictional resistance of the deceleration mechanism, torque is not generated by air blowing until wind power is generated, so a larger motor torque than during steady operation is required.

Conventional reduction mechanisms that are directly connected to the motor shaft use large gears whose strength far exceeds that required for steady operation, making the reduction mechanisms large and expensive.

The purpose of this invention is to provide a reduction gear gear shaft for wind direction grill rotation;
The objective is to reduce the required strength of bearings, support frames, etc., reduce the overall size and weight of the reduction mechanism, simplify the wind direction grill drive mechanism, increase productivity, and reduce the load on the motor at startup. .

In order to achieve the above object, the present invention provides a torque control system that causes the motor shaft to slip with respect to the input shaft when the load torque of the input shaft of the wind direction grill reduction mechanism is larger than that during steady operation. Limitations Next, the configuration of the present invention will be described with reference to embodiments.

In FIG. 2, a large gear 11A fixed to the output shaft 8 of the speed reduction mechanism 7 is meshed with a small gear 12A fixed to the pin 13. Large gear 11B fixed to the other end of pin 13
is the small gear 12B loosely fitted into the small diameter trap at the end of the output shaft 8.
They are interlocked.

As shown in FIG. 3, a rectangular permanent magnet 14 is fixed to the boss of the small gear 12B, and a rectangular magnetic body 15, which is the same as the permanent magnet, is fixed to the rotating shaft 4 of the motor. ing. A magnetic circuit is formed when the permanent magnet 14 and the magnetic body 15 face each other with air gaps 16A and 16B maintained. When the motor rotates, since the magnetic body and the permanent magnet are integrated by magnetic attraction, the rotational force of the motor is transmitted to the speed reduction mechanism. The amount of torque that can be transmitted by this joint is determined by the strength of the permanent magnet, the size of the air gap, and how the cross-sectional area of the magnetic path of the magnetic body is selected. If the load torque exceeds the set transmission torque, the joint slips and acts as a torque limiting joint.

According to the present invention, by setting the transmittable torque of the joint to a level that compensates for the torque generated by wind power, the joint slips under high loads at startup, so the load of the reduction mechanism 6 can be set to the minimum. The purpose of the invention in the title can be achieved.

In addition to the aforementioned torque-limiting joint using a combination of a permanent magnet and a magnetic material, the same effect can be achieved by using a torque-limiting joint using the contact between the friction plate 1 11 17 and the pressure spring 18 shown in FIG. .

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of an electric fan equipped with a rotary wind direction grill, Fig. 2 is a longitudinal cross-sectional view of a reduction mechanism according to the present invention provided with a torque limiting joint, and Fig. 3 is a longitudinal cross-sectional view of a fan equipped with a rotating wind direction grill. Body, 2...
・Motor, 3...Support leg, 4:...Motor rotation axis, 5
... Impeller, 6... Protection net, 7... Reduction mechanism, 8
...Output shaft of the reduction mechanism, 9...Wind direction grill, 10.
... Detent pin, 11... Large gear, 12... Small gear, 13... Pin, 14... Permanent magnet, 15...
Magnetic material, 16... air gap, 17... friction plate, 18...
・Press spring.琐 l Figure 2 3121 40'g S figure

Claims (1)

[Claims] 1. An electric fan characterized in that a torque limiting joint is provided between the rotation axis of the electric fan's motor and the input shaft of the speed reduction mechanism for rotation of the wind direction grill, so that the transmitted torque does not exceed the torque during steady operation.