JPS6033000A - Motor driven blower - Google Patents

Abstract

PURPOSE:To lessen the amount of direction change of the air blowing from the circumference toward the center while absorbing the noise generated at the impeller part by furnishing a bypass at the periphery of fan case, and by equipping this bypass passage with sound absorbing material. CONSTITUTION:The side of wind guide 11 situated nearer its impeller 14 has an impeller chamber 19 and a volute chamber 20 in connection therewith. The termination 20a of this volute chamber is coupled with a communicative hole 21, which leads the air in communication with the volute chamber 20 to that side of wind guide 11 situated nearer the motor. A hole 17d is provided at that portion of fan case periphery 17b mating with said communicative hole 21, and sound absorbing material 18 is installed as covering this hole 17d. Part of the air introduced into the volute chamber 20 by rotation of the impeller 14 is released out through said sound absorbing material 18, while the other portion passes through the exhaust passage 23, cools the motor and then is released out from the exhaust hole.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electric blower used in a vacuum cleaner or the like.

Structure of the conventional example and its problems As shown in FIG. A plurality of divided chambers 4 are provided on the outer periphery, and the passage 6 surrounded by the fan case 3 and the passage 6 formed below the blower guide 2 are communicated from the polynit chamber 4. The air discharged from the outer periphery of the impeller 1 flows through the volute chamber 4, the passage 5, the passage 6, the inside of the motor 7, and the exhaust port 8 of the motor.

For this reason, in this type of electric blower, the air discharged by the impeller 1 due to centrifugal force and flowing toward the outer circumference is largely changed in direction from the passage 6 to the passage 6 and again toward the inner circumference, and the motor 7 The air flow resistance loss was large due to the air passing through the inside of the air, and the air blowing efficiency was not very high.

Invention Q Purpose The present invention solves these conventional problems and provides a highly efficient electric blower.

Structure of the Invention The electric blower of the present invention is provided with a bypass passage on the outer periphery of the fan case, and a sound-absorbing material is provided in this bypass passage, and a part of the air discharged from the impeller is discharged to the outside through the sound-absorbing material of this bypass passage. This reduces the amount of direction change of air from the outer circumference to the inner circumference while absorbing the noise generated in the impeller (and also reduces the amount of air passing inside the motor, reducing ventilation loss and increasing the This was done to improve efficiency.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIGS. 2 and 3, reference numeral 11 denotes a generally disc-shaped air blowing guide fixed to the motor 12, and is arranged concentrically with the motor shaft 13. 14 is an impeller fixed to the motor shaft 13, which has two discs 14a.

14b, and a blade 14c between the discs 14a and 14b. An inlet 15 is provided in the center of the disc 14a, and air flowing in from this population 16 enters the impeller 1.
The centrifugal force caused by the rotation of blade 1 causes the blade to move toward the outer circumference.
It flows out from an outlet 16 surrounded by the terminal end of 4c and the outer periphery of disks 14a and 14b. 17 is the impeller 14 in the center part.
has an inlet 17a corresponding to the inlet 16 of the disk 14a.
The fan case has a shape that follows the shape of the fan case, and its outer circumferential portion 17b surrounds the blower guide 11, and its base portion 17b surrounds the load side plaque of the motor 12.
2a is fitted and fixed to the outer periphery. A semi-breathable sound absorbing material 18 is attached to the outer periphery of the fan case 17. The configurations of the air guide 11, fan case 17, and sound absorbing material 18 will be explained in more detail.

That is, the impeller 14 side of the blower guide 11 has an impeller chamber 19 consisting of a disk-shaped space in which the impeller is located at an angle of 1°4, shown by a dotted line in FIG. A terminal end 20a of the volute chamber 20 is connected to a communication hole 21 that guides the air passing through the volute chamber 20 to the motor 12 side of the blower guide 11. Outer periphery 17 of fan case 17 corresponding to communication port 21
A hole 17d is provided in b, and a sound absorbing material 18 is provided to cover this hole 17d. 22 has one end close to the outer periphery of the impeller 14, and the other end close to the air guide 1 of the communication hole 21.
It is continuous with the part located outside of the center of 1 and has a constant radius of curvature (the radius of curvature may change along the way).

), and the starting end of this wall, that is, the part closest to the impeller 14, has a pollut tongue 22a.
is formed.

Reference numeral 23 denotes an exhaust passage formed on the opposite side to the side where the impeller 14 is located, and is connected to the volute chamber 2o through a communication hole 21 so that the exhaust flow flows from the volute chamber 20 to the exhaust passage 23. ing. As shown in FIG. 2, the terminal end of the exhaust passage 23 communicates with the motor intake hole 12b.

In the above configuration, the inlet 17a of the fan case 17
The incoming air enters the inlet 16 of the impeller 14,
The rotation of the impeller 14 causes it to move in the centrifugal direction and is discharged from the outlet 16. The emitted exhaust gas enters the Polito chamber 20, where it is gradually expanded and converted from dynamic pressure to static pressure, and a part of the flow flows through the hole 17d of the fan case 17 into the sound absorbing material 18. The other flow passes through the side of the sound absorbing material 18 while being absorbed, passes through the communication hole 21, goes around the back side, passes through the exhaust passage 23, and enters the motor intake hole 12b. , after the motor 12 is discharged, it is discharged to the outside from the motor exhaust port 12b.

Next, the noise generated by the rotation of the impeller 14 will be explained. Since the end of the volute tongue 22a of the blower guide 11 is arranged close to the outer periphery of the impeller 14, the rotation of the impeller 14 is affected by J.

The airflow discharged in the centrifugal direction in the vicinity of each blade 14c hits the pollute tongs 22a, and noise is generated at this time. Since this is repeated for each blade, the noise locally increases around a certain frequency □. For example, if the rotation speed is 2150 Or and the number of p6m blades is 7, then (215 oor, p, m /60 seconds) x 7 blades per second 42
500, and a noise of approximately 2500 Hz will be generated.

In this embodiment, the noise generated by the polyto tongs 22a is absorbed by the sound absorbing material 18. Also, conventional motor 1
Because all the air was flowing through the inside of the motor 12, a large wind noise was generated when it passed through the rotating parts and windings of the motor. However, by bypassing some of the air through the hole 17d, By reducing the amount of air passing through the windshield, wind noise can be reduced, reducing noise.

In addition, by bypassing a portion of the air through the hole 17d, it is possible to prevent a decrease in efficiency due to a change in direction of the air flow from outside to inside, and also to prevent a decrease in efficiency due to ventilation resistance within the motor 12, which improves air blowing efficiency. Significant improvements can be made.

Effects of the Invention As is clear from the above embodiments, according to the present invention, it is possible to provide a highly efficient electric blower with reduced noise.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing a conventional electric blower, Fig. 2 is a cutaway side view of essential parts of an electric blower showing an embodiment of the present invention, and Fig. 3 is a front sectional view of the blower section. . 11...Blower guide, 12...Motor, 12b...Motor intake hole, 14...
・・Impeller, 17゛゛・・Fan case, 17d・
...hole, 18 ... sound absorbing material, 20 ...
・Polyto room, 21...Communication path (communication hole). Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] Multiple polyneedle chambers facing the outer periphery of the impeller, a communication passage that guides the polyneedle chambers to the outer circumference, and then from the outer circumference to the back side, and a passageway that leads the exhaust gas inward to the motor intake hole on the back side. The fan case includes an air blowing guide and a fan case that surrounds the outer periphery and upper surface of the impeller and the air blowing guide, the outer periphery of the communication path of the air blowing guide is formed by the fan case, and a hole is formed in a portion of the fan case opposite to the communication path. An electric blower with holes covered with semi-breathable sound absorbing material.