JPH0552200A - Motor-driven blower - Google Patents

Abstract

PURPOSE:To improve efficiency of an electric motor by restraining rise of temperature of brushes and a rotor of a motor-driven blower motor. CONSTITUTION:A rotor 23 is arranged in a housing 21 of an electric motor of a motor-driven blower, a pair of coils 44a, 44b is provided and a pair of brushes 58a, 58b is installed. A rotor wound with the coils 44a, 44b is formed in a rectangular shape and fixed inside of the cylindrical housing 21 in the angular part closed state. A space on the side of the coils 44a, 44b is blocked with a plate 60 and cooling air is passed only through spaces A, B. Consequently, this improves efficiency of the electric motor by cooling the brushes 58a, 58b and preventing them from rising in temperature and overheating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system for an electric blower, and more particularly to a cooling structure for a commutator type motor.

[0002]

2. Description of the Related Art Conventionally, as a cooling air flow path configuration of an electric blower using a commutator type motor, as described in JP-B-2-32879, the direction of the stator winding is orthogonal to the brush device side. There was a method of providing a main flow path.

[0003]

In the above-mentioned conventional example, although it is effective in terms of cooling of the stator winding or air blowing performance, it is effective in cooling the rotor winding or of the commutator and brush device. No consideration was given to cooling.

Actually, the temperature rise is generally high in the rotor side winding, which has a higher current density than in the stator side, and the temperature rises especially at the sliding part between the brush and the commutator, but the temperature rises as described above. In such a conventional structure, since the cooling air mainly passes through the outside of the stator, the rotor is not cooled, and since it is the stator winding side air passage, it is difficult to cool the brush device portion.

Accordingly, in recent years, as a motor for a vacuum cleaner, in which the competition for high power has become particularly intense, the temperature rises with the conventional structure, and eventually the efficiency of the motor decreases and the temperature of the brush increases. There is a risk that the motor life will be shortened and the commutation failure and early brush wear will occur, shortening the motor life. An object of the present invention is to improve reliability in a commutator motor by suppressing an increase in rotor winding temperature, improving motor efficiency, and suppressing an increase in brush temperature.

[0006]

In order to achieve the above object, the present invention uses a plate on the stator winding side of the space with the inner surface of the housing formed outside each side of the substantially rectangular stator core. Block the side facing the brush device side,
This is achieved by configuring as a cooling air passage.

[0007]

When the electric blower is operated, the exhaust flow of the fan is guided to the intake port of the embra by the fixed guide vanes arranged on the outer circumference.

After that, the exhaust flow passes through the inside of the motor housing, and since the inside of the housing passes through the flow passage formed between the outside of the stator core on the brush device side and the inside of the housing, the cooling air is directly passed. Hits the brush device and is cooled intensively.

Therefore, it is possible to effectively cool the brush, prevent premature wear of the brush due to high temperature overheating, abnormal phenomena such as defective commutation, and improve reliability.

Further, since the sliding portion between the brush and the commutator, which has the highest temperature, is also cooled, the temperature rise of the rotor winding connected to the commutator can be suppressed and the motor efficiency can be improved. it can.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

First, FIG. 1 shows an example applied to an electric blower used in an electric vacuum cleaner.

The electric blower 1 is composed of an electric motor section 2 and a blower section 3.

The electric motor section 2 is a commutator type electric motor, and a rotor 23 and a stator 24 are housed in a housing 21 and an end bracket 22 as shown in FIG. The stator 24 has a two-pole configuration, and a pair of brush devices 58 arranged between the pair of windings 44 a and 44 b are mounted on the housing 21. As shown in FIG. 2, the stator core formed in a rectangular shape is fixed in a cylindrical housing 21 in a state where the corner portions are in close contact with each other, and between each four sides of the rectangle and the inner surface of the housing 21,
Spaces A, B, C and D are formed respectively and face the brush device 58 and the stator windings 44a and 44b. As shown in FIG. 4, a plate 60 that closes the space is disposed in the spaces C and D on the side of the stator windings 44a and 44b. Further, an intake port 22a is provided in the space A, B direction of the end bracket 22.

The rotor 23 is supported by bearings 25a and 25b, and the rotary shaft 26 penetrates the end bracket 22 and extends toward the blower unit 3 side.

In the blower unit 3, a fixed guide vane 31 is arranged on the end bracket 22, and a centrifugal impeller 32 is arranged integrally fixed to the rotary shaft 26, and a casing 33 is covered to cover them. , Is fixed to the outer circumference of the end bracket 22 by press fitting.

When the electric motor section 2 is energized, the centrifugal impeller 32 rotates together with the rotary shaft 26, sucks air from the inlet section 32a and discharges it from the outer peripheral section 32b.

Thereafter, the exhaust gas is guided to the suction port 22a of the end bracket 22 through the fixed guide vane 31,
The rotor 23, the stator 24, the brush device 58, the commutator 23a, etc., which flow into the electric motor section 2 from the suction port 22a and whose temperature rises during operation, are cooled, and the housing 2
It is discharged to the outside from the first exhaust port 21a.

Generally, in a commutator motor, the rotor winding 43 has a higher current density than the stator windings 44a and 44b,
In addition, the gap between the rotor core 53 and the stator core 54 is
Since the magnetic path structure is formed to be narrow, it is difficult for the cooling air to flow, and the temperature of the rotor 23 including the rotor winding 43 rises high.

Further, the brush 58 sliding during rotation.
Since a and b and the commutator 23a have the highest temperature,
Since the rotor winding 43 connected to the commutator 23a is heated and its temperature rises, the temperature becomes higher than that of the stator windings 44a, 44b.

Conventionally, in order to improve the aerodynamic performance of the electric blower 1, there has been a method of providing an air passage in the outer circumferential space on the stator winding side as described in Japanese Utility Model Publication No. 2-32879. However, no consideration was given to the cooling of the rotor 23 and the brush device 58.

In particular, as the electric blower used for a vacuum cleaner which has recently been highly competitive in high power, the rotor 23 is used.
Also, the increased temperature of the brush device 58 may reduce the efficiency and reliability of the electric motor.

In the present embodiment, in the space ABCD formed on the outer periphery of the stator core 54, the stator windings 44a, b side C, D are closed by the plate 60, and the cooling air is blown to the brush device 58 side air passage. By passing only B and D,
The brush device 58 is intensively cooled to suppress the temperature rise of the brush.

As a result, instability factors such as premature wear due to overheating of the brush and incomplete rectification can be eliminated to improve reliability. Further, by lowering the temperatures of the brushes 58a and 58b, the temperature between the highest temperature brushes 58a and 58b and the commutator 23a can be similarly reduced, so that the temperature rise of the rotor winding 43 is suppressed and the motor efficiency is reduced. Is improved.

If instead of the plate 60, the end bracket 22 is provided with a backing plate portion 22b to block the air passages C and D and to make cooling air flow only to A and B,
As mentioned above, it can be cooled without increasing the number of parts,
The reliability can be improved.

[0026]

According to the present invention, the brushes 58a and 58b are centrally cooled without increasing the number of parts, so that the temperature rise is suppressed and the commutation failure, the astringency, the early wear, etc. are prevented and the reliability is improved. Can be improved.

Further, since the commutator 23a which rotates and slides with the brushes 58a, 58b is also cooled, the rotor winding 43 connected to the commutator 23a is also cooled and the temperature rise is suppressed, so that the efficiency of the motor is improved. Improvement is achieved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an electric blower according to an embodiment of the present invention.

2 is a perspective view showing the assembly of the electric motor unit 2. FIG.

FIG. 3 is a cross-sectional view of an electric motor unit 2.

FIG. 4 is a cross-sectional view of the electric motor unit 2 of the embodiment.

[Explanation of symbols]

21 ... Housing, 24 ... Stator, 44a, b ... Stator winding, 54 ... Stator core, 60 ... Plate.

Claims (3)

[Claims] 1. An end bracket having a suction port is provided on an end face on the opening side of the housing, the stator and the rotor being housed in a housing having a cylindrical portion with one end opened, and the end bracket having the suction port. However, an electric motor equipped with a fan in which the bearing support portion of the end bracket is mounted on the shaft of a rotor passing through, a fixed guide vane that guides the exhaust flow of the fan to the intake port of the end bracket, and a fan casing that covers the fan guide fan In the blower, the outer shape of the stator iron core as viewed from the axial direction is substantially rectangular, and the brush device is arranged between two poles of the stator winding. Closely contact the inner surface of the cylinder,
2 of each side of the rectangle facing the brush device
An electric blower, wherein a space formed between a side and an inner surface of the housing serves as an air passage for exhaust air from the fan. 2. The electric blower according to claim 1, further comprising: a plate that closes a ventilation path between the two sides of the stator core and the inner surface of the housing. 3. The electric blower according to claim 1, wherein the suction port of the end bracket is provided in the brush device side air passage direction.