JPH069559Y2 - Structure of resin can for motor - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to the structure of a can of a canned motor. The efficiency of the canned motor has been improved by minimizing copper loss, eddy current loss, iron loss, etc. due to the increase in air gap due to the presence of a conventional metal can. It is a thing.

[Prior art]

As shown in FIG. 1, the canned motor includes a hollow cylindrical can 5 in a gap 4 between the stator 2 of the motor 1 and the rotor 3.
The stator 2 is closely fitted to the inside of the stator 2, and the drive shaft of the compressor or pump 6 directly connected to the motor and serving as a load and the shaft of the rotor of the motor are combined and integrally sealed. However, the can 5 is used to completely isolate the fluid from the outside air, except for the fluid leakage portion from the penetration portion of the drive shaft of the load. The air gap 4 in which the can 5 is inserted is an important part that directly affects the characteristics of the motor because the magnetic flux of the stator 2 penetrates. However, the air gap 4 must be increased in order to allow the can to exist. For this reason, the exciting current increases, and the copper loss increases accordingly. Since the can has conductivity because it is metallic, a closed circuit is formed in the can, and eddy current loss occurs. These losses reduce the characteristics of the canned motor, particularly the efficiency, and make it extremely difficult to design a large capacity canned motor. For this reason, a canned motor using a soft magnetic material with high magnetic permeability and high resistance has been used to reduce copper loss and improve efficiency, but even so, there is a limit to the development of an ideal metallic can material. However, it is still in the present situation that cannot be said to be sufficient.

[Means for Solving the Problems]

The present invention has been made in view of such a point, and is a heat-resistant, high-strength resin material having no heat expansion and extensibility, which is a hermetically sealed resin material. Is an attempt to improve the efficiency of a canned motor by kneading a soft magnetic metal fine powder having a low iron loss in a polyimide-based heat-resistant resin and forming it into a ring to form a can.

【effect】

The can has a thin-walled cylindrical shape and has heat resistance against positive and negative temperatures, high strength against pressure, corrosion resistance against various gases and liquids, airtight resistance against gas leakage, etc., and is easy to process, Ideally, it should be a material that is electrically high insulating material, does not generate eddy current loss, has high magnetic permeability to facilitate the passage of air gap magnetic flux, and has various characteristics such as low iron loss. However, there is no material that completely satisfies this. Therefore, the present invention aims to achieve the above-mentioned characteristic requirements by combining two materials without achieving them by one material. That is, the electromagnetic characteristics were achieved by dispersing a soft magnetic metal fine powder having high magnetic permeability, low eddy current loss, low iron loss, etc. in the resin, and electrically insulating the can. The properties, mechanical strength, workability, etc. are achieved with a polyimide resin. In particular, a polyimide resin is generally used for an ink ribbon of a thermal transfer printer, and despite having extensibility, high heat resistance against positive and negative temperatures, high strength against pressure, particularly non-elongation, It has corrosion resistance to various gases and liquids, and is particularly malleable, so it is easy to process.

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the shape, numerical values, specifications, relative arrangement, etc. of the constituent elements described in this embodiment are not intended to limit the scope of the present invention thereto, unless otherwise specified.
It is merely an example of explanation. FIG. 2A shows the shape of the can, and FIG. 2B shows a partially enlarged view thereof. Reference numeral 5 is a can in which the soft magnetic fine powder 8 is kneaded in the polyimide resin material 7 having the above-mentioned characteristics. Generally, the thickness of the can 5 is 2 to 3 mm or less depending on the capacity of the canned motor. As an example of the soft magnetic metal material, fine powder of amorphous magnetic material of about several microns can be dispersed and used. The characteristics of the thus constructed canned motor have a negligibly small value compared to the loss inherent to the motor, because the motor power source is at the commercial frequency and the eddy current loss and the iron loss are negligible. The ratio of the magnetic powder to the resin is related to the magnetic permeability, which reduces the exciting current and consequently the copper loss. However, the increase of the ratio of the magnetic powder to the resin also decreases the strength of the can itself. Involved. The optimum value of this ratio will be found from the characteristics of both, but mechanical strength must be prioritized. The loss due to the can in the conventional canned motor is determined by the capacity of the motor, and its value is close to the motor loss. If the motor loss is assumed to be 8%, the loss due to the can is also about 8%, the total loss is 16%, and the efficiency is 84%. However, according to the can of the present application, the can loss is so large as to be negligible with respect to the loss peculiar to the motor. Therefore, if the above example is adopted, even if the can loss is 8% and the can loss is 2%, The total efficiency is 90%, which greatly contributes to reduction of motor loss, improvement of efficiency, and energy saving, and also makes it easy to design a large capacity canned motor.

[Brief description of drawings]

FIG. 1 is a side view of the canned motor, FIG. 2 (a) is a can shape diagram, and (b) is a partially enlarged view thereof. 1; canned motor, 2; stator, 3; rotor, 4; air gap, 5; can, 6; load, 7; resin material,
8: Soft magnetic fine powder

Claims (1)

[Scope of utility model registration request] 1. A heat-resistant resin of polyimide type is kneaded with a fine powder of a soft magnetic metal metal having a low iron loss and formed into an annular shape, which is closely fitted to the inside of the stator to form a can. Structure of resin can for canned motor.