JPH07264802A - Induction motor - Google Patents

Abstract

PURPOSE:To accelerate the transmission of heat which is transmitted by a stator, the air flowing on the backside of the stator or the convection from the air to a housing by a method wherein three-dimensional protrusions whose cross-sections are changed in the direction of the air flow are provided. CONSTITUTION:An induction motor absorbs the air by a fan attached to a rotor through windows opened in a casing 5. The air is made to flow through a ventilation guide to the backside of a stator 3. Ribs 8 which are distributed in a circumferential direction between the stator 3 and the casing 3 are provided intermittently. By providing the ribs 8 intermittently, the main flows of the air are well mixed and the increase of a pressure loss is smaller than a pressure loss when a conventional continuous rib is used, so that the heat transmission is accelerated with a same fan power. If the ribs are formed by a pressing process, etc., from the outside of the casing 5, the heat radiation area of the outside of the casing 5 is also increased by the pressing process, etc., and a heat radiation performance is increased. As a result, the cooling effect of the induction motor is improved and the coil temperature of the motor is lowered, so that a small and highly reliable induction motor can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor cooling structure for cooling heat generated by an electric motor.

[0002]

2. Description of the Related Art In order to cool heat generated from a stator (stator) and a rotor (rotor) of an induction motor, the back surface of the stator is also cooled (Japanese Utility Model Publication No. 60-192646).
In this case, on the back surface of the stator, plates whose cross-section does not change in the axial direction (ventilation direction) are provided between the housings.

[0003]

When a material having a high thermal conductivity such as aluminum is used as the housing material,
Considering the heat resistance of the heat radiation system, it is necessary to enhance heat transfer by air flowing through the stator and the back surface of the stator or by convection from the air to the housing. Even if only the housing has high thermal conductivity, if the thermal resistance due to convection is large, the total cooling amount does not increase.

[0004]

The heat transfer by convection can be increased by providing three-dimensional projections whose cross-section changes in the direction of the air flow. In this case, the flow rate passing through the back surface of the stator may be reduced due to the increase in pressure loss, but the heat dissipation performance is improved due to the increase in the heat transfer area and the fine disturbance due to the turbulent flow. However, the structure should be such that the pressure loss does not increase as much as possible.

[0005]

The heat transfer coefficient is increased by forming intermittent three-dimensional projections on the rear surface of the stator not only from the housing side but also from the stator side. The protrusions are rounded to generate vortices as smoothly as possible to prevent an increase in pressure loss due to the formation of large vortices due to peeling.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fan 4 attached to a rotor 2 of an induction motor composed of a shaft 1, a rotor 2 and a stator 3 as shown in FIG.
In the system in which the air is absorbed from the open window 6 of the casing 5 and the air is allowed to flow to the back surface of the stator 3 via the blower guide 7, the ribs 8 distributed between the stator 3 and the casing 5 in the circumferential direction are intermittently connected. The heat transfer coefficient of the back surface of the stator is improved by providing the heat transfer coefficient. By providing the ribs 8 intermittently, the mixing between the main flows is improved, the increase in pressure loss is smaller than that in continuous ribs, and heat transfer is promoted by the same fan power. According to the calculation, the heat from the stator 3 is once transferred to the air flow, but if the heat transfer coefficient between the casing 5 and the air flow is high, the heat may also be dissipated from the casing portion outside the stator. To be Therefore, it is necessary to increase the heat transfer coefficient both between the stator and the air flow and between the air flow and the casing. In these structures, this method is more effective when the casing has a high thermal conductivity (203 W / mK) like aluminum because the convection part has a larger thermal resistance.

As shown as another embodiment in FIG. 2, ribs 8 are formed from the outside of the casing 5 by pressing. Also on the outside of the casing 5, the heat radiation area is increased by the pressing process and the like, and the heat radiation performance is improved.
The arrows in the figure represent the airflow flowing through the flow path between the casing 5 and the stator 3.

As shown in FIG. 3, ribs 8 are arranged in a zigzag pattern to generate finer vortices necessary for improving heat transfer performance, thereby improving the heat transfer coefficient. In the pressing process, as shown in FIG. 4, the rib mold 21 of the press mold 20 is moved to the casing 5
Then, the rib 8 is formed by pressing the raw material. The pressing process is performed by inserting the raw material of the casing 5 between the press die 20 and the press pedestal 22.

As shown in FIG. 6, the casing 5 is formed by bending a material plate of the casing 5 provided with ribs 8 and welding the ends thereof.

As shown in FIG. 7, by forming the rib 10 from the casing 5 into a rhombus, the flow resistance is reduced. Further, a structure in which the opening 11 is partially provided in the housing to promote the circulation of air is also effective.

FIG. 8 is a view showing another embodiment, in which the rib 23 extending from the casing 5 has a circular shape, which has an advantage that pressure loss is reduced, but the heat transfer coefficient is also slightly reduced. .

As shown in FIG. 9, the rib 2 from the casing 5
It is also effective when making 4 streamlined.

In FIG. 10, ribs 26 are attached to a steel plate 25 such as an electromagnetic steel plate forming a stator. By partially laminating these plates 25 as shown in FIG. 11,
A rectangular rib is formed in contact with the casing 5. The part 27 where no rib is formed is formed by laminating steel plates having no rib 26, which is close to a normal disc.

FIG. 12 shows a rib 28 inside the casing 5.
Welded to the rib 28
Heat is dissipated through the.

FIG. 13 is a view showing a manufacturing method using an aluminum die casting, in which the projection 3 of the aluminum die casting mold 29 is used.
0 is transferred from the inside of the aluminum housing. The cylinder 31 is inserted when transferring by the mold, but the cylinder is taken out when the mold 30 is pulled out. The effect is further enhanced by providing the radiation fins 33 on the outside of the casing 5 and increasing the heat radiation to the outside as the heat transfer between the housing and the airflow increases.

FIG. 14 shows a case where the casing rib 8 and the stator 3 are not in contact with each other, which has an effect of reducing the flow resistance of air. In this case, if some of the ribs 8 are in contact with the stator 3, the stator 3
Can be fixed.

[0017]

According to the present invention, if the cooling effect is enhanced,
Since the coil temperature of the motor is low, the induction motor can be made compact and highly reliable.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a partial perspective view showing an embodiment of the present invention.

FIG. 3 is a partial perspective view showing a second embodiment of the present invention.

FIG. 4 is a perspective view showing a second embodiment of the present invention.

FIG. 5 is a sectional view showing a third embodiment of the present invention.

FIG. 6 is a sectional view showing a fourth embodiment of the present invention.

FIG. 7 is a partial perspective view showing a fifth embodiment of the present invention.

FIG. 8 is a partial perspective view showing a sixth embodiment of the present invention.

FIG. 9 is a partial perspective view showing a seventh embodiment of the present invention.

FIG. 10 is a front view showing a component of the present invention.

FIG. 11 is a partial perspective view showing an eighth embodiment of the present invention.

FIG. 12 is a partial perspective view showing a ninth embodiment of the present invention.

FIG. 13 is a partial perspective view showing the manufacturing method of the present invention.

FIG. 14 is a partial perspective view showing the manufacturing method of the present invention.

FIG. 15 is a partial perspective view showing a tenth embodiment of the present invention.

[Explanation of symbols]

1 ... Shaft, 2 ... Rotor, 3 ... Stator, 4 ... Fan,
5 ... Casing, 6 ... Ventilation window, 7 ... Guide, 8 ... Casing rib.

Front page continued (72) Inventor Go Omata 7-1, Higashi Narashino, Narashino City, Chiba Prefecture Industrial Equipment Division, Hitachi, Ltd. (72) Inventor Eiichiro Sugawa 7-1, Higashi Narashino, Narashino City, Chiba Co., Ltd. Hitachi Industrial Equipment Division

Claims (1)

[Claims] 1. An induction motor comprising a stator, a rotor, a fan attached to the rotor, a shaft, a housing, and a blower guide, wherein an intermittent rib is provided so as to contact the back surface of the stator. Electric motor.