JPH0122959Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an electric blower used in a vacuum cleaner or the like.

Conventional configurations and their problems Conventionally, electric blowers used in vacuum cleaners include those in which a centrifugal impeller is directly connected to a high-speed rotating commutator motor. By using this commutator motor, it is possible to make the motor smaller and faster than an induction motor. but,
In the case of a commutator motor, since the temperature rises significantly during operation, it is necessary to cool the motor, and this is generally cooled by the discharge airflow from the impeller.
Therefore, the structure is such that the airflow discharged from the impeller passes through a passage leading into the inside of the motor.

In the case of a centrifugal impeller, the impeller generates kinetic energy, that is, dynamic pressure,
Efficiency is increased by generating pressure energy, that is, static pressure, and converting this dynamic pressure into static pressure.
As a means for converting this dynamic pressure into static pressure, a volute portion is provided around the impeller.

The volute part and the exhaust passage are integrated around the impeller for the two purposes shown above, namely, converting dynamic pressure into static pressure and guiding airflow into the motor. Impellers equipped with air guides are common.

Fig. 1 shows the general configuration of an electric blower. 1 is a casing, with an intake port 2 opened in the center, and a motor frame 3 on the opposite side from which there is no air leakage. It is installed like this. 4 is a centrifugal impeller having a plurality of blades 4; 5 is a volute portion 5a for converting the dynamic pressure generated by the impeller 4 into static pressure; and an exhaust passage that guides the discharge airflow from the impeller 4 into the inside of the motor. 5b is integrally formed with the air guide.
6 is a motor that drives the impeller 4.

When the impeller 4 is rotated by the motor 6, air is sucked in through the intake port 2 of the casing 1, passes through the inside of the impeller 4, the air guide 5, and the inside of the motor 6, and is discharged to the outside.

Now, if we consider the dynamic pressure and static pressure generated by the electric blower, the airflow discharged from the impeller 4 has a high dynamic pressure component and a high speed. The discharged airflow is converted into static pressure by the volute section 5a, and guided into the motor 6 through the exhaust passage 5b. As described above, the airflow exiting the impeller 4 and the exhaust passage 5b
There is a pressure difference in the airflow passing through the airflow due to the conversion from dynamic pressure to static pressure by the air guide 5. Due to this differential pressure, the motor shaft 6a is
Conventionally, measures as shown in Figure 1 have been taken to prevent airflow from leaking to the sides. In FIG. 1, the exhaust passage 5b of the air guide 5 is
The structure was such that the lower wall 5c of the motor frame 3 was brought into close contact with the motor frame 3.

However, the above configuration has the disadvantage that the dense line portion is only on one side and cannot sufficiently prevent leakage of airflow. In addition, in order to ensure close contact between the two, the motor frame is bent upward, and the lower wall of the air guide is brought into contact with the lower wall of the air guide to forcibly deform it (Japanese Utility Model Publication No. 56-133998). However, in this case, the above deformation causes the support of the motor shaft to become distorted, and as a result,
There were problems such as shaft vibration and uneven load being applied to the bearing.

Purpose of the invention The present invention aims to improve the above-mentioned conventional drawback of airflow leakage and to provide an electric blower that can reliably prevent leakage.

Structure of the Invention In order to achieve the above object, the present invention includes a commutator motor, a motor frame attached to the motor and having a ventilation hole for inflowing cooling air, an impeller, and a movement of the airflow discharged from the impeller. an air guide having a volute part that changes pressure to static pressure and an exhaust passage that guides airflow from the volute part to a vent in the motor frame, and a casing that is attached to the outer periphery of the motor frame and contains the air guide and the impeller. The lower wall of the air guide has a concave portion, and the motor frame has a convex portion that fits into the concave portion.

In the above configuration, when the airflow discharged from the impeller flows through the volute part of the air guide, its dynamic pressure is converted into static pressure, and then the airflow flows from the exhaust passage into the commutator motor through the ventilation hole of the motor frame. The motor is guided and cooled. In addition, a concave part is provided on the lower wall of the air guide and a convex part is provided on the motor frame, and a ravinin structure is adopted by fitting these concave and convex parts to increase ventilation resistance, thereby preventing air leakage between the air guide and the motor frame. be done.

Particularly in the motor frame, the formation of the convex portion provides reinforcement and prevents deformation.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention is shown in FIGS. 2 and 3. In FIG. 2, 11 is a casing having an intake port 12 and attached to the outer periphery of the motor frame 13 in an airtight manner; 14 is a casing having a plurality of blades 4;
The centrifugal impeller 15 has a volute part 15a for converting the dynamic pressure generated in the impeller 14 into static pressure, and an exhaust passage 15b that guides the airflow passing through the volute part 15a to the inside of the motor 16. This is an air guide that is integrally formed with. The air guide 15 and impeller 14 are enclosed in the casing 11. As shown in FIG. 3, a convex portion 13a is formed on the inner peripheral portion of the ventilation hole 13b provided in the motor frame 13 by bending it upward. Further, the lower wall of the air guide 15 has a concave portion 15c into which the convex portion 13a of the motor frame 13 fits.
is formed. And this recessed part 15c and the convex part 1
3a forms a sealing portion 17 that prevents airflow from leaking toward the motor shaft 16a by a ravinin effect.

In the above configuration, since the seal portion 17 between the motor frame 13 and the air guide 15 extends the air leakage passage, the airtightness of the air is increased and leakage due to the dynamic pressure generated in the impeller 14 is prevented. This increases efficiency. Furthermore, the rigidity of the motor frame 13 is increased and the amount of motor frame material can be reduced at the same time, which has great effects.

Effects of the invention The electric blower of the invention forms a seal between the motor frame and the air guide by convex-concave fitting, which easily prevents air leakage, reduces pressure loss, and increases efficiency. I was able to do that. Furthermore, by forming the convex portion on the motor frame, its rigidity is increased. This rigidity is extremely effective in reducing noise by eliminating vibration in the frame, and also has the following important effects. That is, in this type of electric blower, one of the bearings for supporting the motor shaft is attached to the motor frame. In other words, the motor frame serves as a mounting reference portion for the bearing. However, if the rigidity of this frame is high, the above-mentioned mounting standard can be set reliably, and vibration of the motor shaft and uneven load on the bearing can be eliminated. This has an excellent effect on smooth rotation of the impeller and prevention of bearing overheating and damage.

[Brief explanation of the drawing]

Fig. 1 is a partially cut-out side view of a conventional electric blower, Fig. 2 is a partially cut-out side view of an electric blower showing an embodiment of the present invention, and Fig. 3 is the shape of the motor frame. FIG. 11...Casing, 12...Intake port, 13...
...Motor frame, 13a... Convex portion, 14... Impeller, 15... Air guide, 15c... Concave portion,
17...Seal part.

Claims (1)

[Scope of utility model registration request] A commutator motor, a motor frame attached to the motor and having a ventilation hole for cooling air inflow, an impeller, a volute part that changes the dynamic pressure of the airflow discharged from the impeller into static pressure, and the volute part. The air guide has an exhaust passage that guides the airflow from the motor frame to the ventilation hole of the motor frame, and a casing that is attached to the outer periphery of the motor frame and contains the air guide and the impeller. On the other hand, the electric blower has a convex part formed on the motor frame that fits into the concave part.