JPH11303746A - Motor-driven compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent a leakage of magnetic flux from a permanent magnet by providing end plates made of a nonmagnetic material between balance weights and a permanent magnet, and forming caulking pins caulking the balance weights to at least one end of a rotor with a nonmagnetic material. SOLUTION: When this motor-driven compressor is operated, a crankshaft 5 is rotated as a rotor 4 is rotated, a piston 6 is reciprocated, and gas is compressed and discharged through a discharge pipe. A permanent magnet 7 is internally provided in the rotor 4, and balance weights 9 made of a ferromagnetic material are fitted to the rotor 4. The balance weights 9 are fixed to both ends of the rotor 4 by caulking pins 8 made of aluminum which is a nonmagnetic material. End plates 10 made of a nonmagnetic material are provided between the permanent magnet 7 and the balance weights 9 made of the ferromagnetic material, and a leakage of magnetic flux from the permanent magnet 7 is effectively prevented in cooperation with the caulking pins 8 made of the nonmagnetic material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric compressor connected to a refrigeration cycle such as an electric refrigerator, and more particularly to a technique of a rotor of an electric element.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of environmental protection, CFC-based refrigerants used in electric compressors, for example, R12, contain chlorine in the molecule, so that even if a small amount is released into the atmosphere, even a small amount of the stratospheric refrigerant is generated. Destruction of large amounts of ozone is being elucidated, and switching to alternative refrigerants of HC-based (R600a) and FHC-based (R134a, R410A, R407C) that do not contain chlorine is rapidly progressing. Also, it is necessary to reduce energy consumption in order to prevent global warming, and to improve the energy efficiency of electric compressors, brushless motors have begun to be used for the electric motors. Refrigeration capacity control.

[0003] The rotor of the brushless motor is provided with a balance weight for balancing imbalance during rotation of the compression element. The rotor of the brushless motor includes a permanent magnet, and a balance weight formed of a non-magnetic material is used to prevent leakage of magnetic flux.
FIG. 3 is a sectional view of an electric compressor using a conventional brushless motor. FIG. 4 is a sectional view of a main part of FIG. A compression element 2 and a motor element (brushless motor) 3 are provided in a container 1, and a crankshaft 5 is shrink-fitted to a rotor 4 of the motor element 3, and a piston 6 is attached to a tip of the crankshaft 5.
Is attached. In the electric compressor configured as described above, when the electric compressor starts operating, the rotor 4 rotates, the crankshaft 5 rotates, and the piston 6 reciprocates to compress gas. Reference numeral 7 denotes a permanent magnet housed in the rotor 4, reference numeral 8 denotes a caulking pin formed of a ferromagnetic steel material, and reference numeral 9 denotes a non-magnetic member fixed to at least one end of the rotor by a caulking pin 8 penetrating the rotor 4. A balance weight 10 formed of brass as a body is an end plate formed of brass as a non-magnetic body, and is interposed between the balance weight 9 and the permanent magnet 7. Other components and operations are the same as those of the conventional example.

[0004]

However, in the above-described conventional configuration, the magnetic flux from the permanent magnet 7 is transmitted to the caulking pin 8 which is a ferromagnetic material, and leaks to the balance weight 9.
The balance weight 9 must be formed of a non-magnetic material such as brass, and has a problem that it is expensive.

An object of the present invention is to solve the above-mentioned conventional problems and to prevent the leakage of magnetic flux at a low cost.

[0006]

According to the first aspect of the present invention, an end plate made of a non-magnetic material is interposed between a balance weight and a permanent magnet.
The swaging pin is made of a non-magnetic material.

In order to solve the above problem, according to the present invention, the caulking pin is formed of aluminum.

In order to solve the above-mentioned problem, according to the present invention, the end plate is formed of brass.

In order to solve the above-mentioned problem, according to the present invention, the balance weight is formed of an iron plate.

As a result, the leakage of magnetic flux can be prevented, and the balance weight can be formed at low cost.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 of the present invention comprises a compression element and a brushless motor for driving the compression element. An electric compressor in which a balance weight for balancing unbalance during rotation is fixed to at least one end of the rotor by a caulking pin that penetrates the rotor, between the balance weight and the permanent magnet. An electric compressor having an end plate made of a non-magnetic material interposed and the caulking pin made of a non-magnetic material, which can prevent leakage of magnetic flux from a permanent magnet.

According to a second aspect of the present invention, there is provided the electric compressor according to the first aspect, wherein the caulking pins are formed of aluminum. Since aluminum is softer than steel,
This has the effect that the caulking operation can be easily performed.

According to a third aspect of the present invention, there is provided the electric compressor according to the first aspect, wherein the end plate is formed of brass. Since the brass has strength even if it is made of a thin plate, the end plate is formed at the time of forming the rotor. This has the effect that the above distortion can be avoided.

According to a fourth aspect of the present invention, the balance weight is formed of an iron plate.
The electric compressor according to the above, wherein an end plate formed of a non-magnetic material is interposed between the balance weight and the permanent magnet, and since the caulking pins are formed of the non-magnetic material, leakage of magnetic flux can be prevented. And the balance weight can be formed by an inexpensive iron plate.

[0015]

Embodiments of the present invention will be described below with reference to FIGS. The same parts as in the conventional example are denoted by the same reference numerals,
Detailed description is omitted.

(Embodiment 1) FIG. 1 is a sectional view of an electric compressor according to an embodiment of the present invention shown in claims 1 to 4, and FIG.
4 is a rotor, 4 is a rotor, 7 is a permanent magnet formed of strontium ferrite contained in the rotor 4, 9 is a balance weight formed by stacking SPCC steel plates, which are ferromagnetic materials, and 10 is a balance weight. Balance weight 9 and permanent magnet 7
An end plate made of brass, which is a non-magnetic material, is interposed between the end plates, 8 is a caulking pin made of aluminum, which is a non-magnetic material, and balance weights 9 penetrate the rotor 4 at both ends of the rotor 4. It is fixed by swaging pins 8. With the above configuration, the magnetic flux of the permanent magnet is generated by interposing an end plate that is a non-magnetic material between the permanent magnet and the balance weight that is a ferromagnetic material, and forming the caulking pin with a non-magnetic material. Leakage of magnetic flux can be prevented. By changing the material of the balance weight from expensive brass to SPCC, material cost can be reduced by about 75%, and leakage of magnetic flux can be prevented at low cost.

[0017]

As apparent from the above embodiment, claim 1
According to the invention described above, the rotor of the brushless motor is provided with a permanent magnet therein, and a balance weight for balancing imbalance during rotation of the compression element is provided at least at one end of the rotor with a caulking pin penetrating the rotor. An electric compressor fixed by the above, wherein an end plate formed of a non-magnetic material is interposed between the balance weight and the permanent magnet, and the caulking pin is formed of the non-magnetic material. This has the advantageous effect of preventing the leakage of magnetic flux from the coil.

According to the second aspect of the present invention, there is provided the electric compressor in which the caulking pins are formed of aluminum. Since aluminum is softer than steel, an advantageous effect that the caulking operation can be easily performed can be obtained.

According to the third aspect of the present invention, there is provided an electric compressor in which the end plate is formed of brass, and since brass is strong even if it is thin, distortion on the end plate at the time of forming the rotor can be avoided. The advantageous effect described above can be obtained.

According to the fourth aspect of the present invention, since the end plate made of a non-magnetic material is interposed between the balance weight and the permanent magnet, and the caulking pin is made of the non-magnetic material, the magnetic flux is increased. And the balance weight can be formed with an inexpensive iron plate.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electric compressor according to an embodiment of the present invention described in claims 1, 2, 3, and 4;

FIG. 2 is a sectional view of a main part of the electric compressor according to the embodiment of the present invention described in claims 1, 2, 3, and 4;

FIG. 3 is a cross-sectional view of an electric compressor using a conventional brushless motor.

FIG. 4 is a sectional view of a main part of an electric compressor using a conventional brushless motor.

[Explanation of symbols]

 4 Rotor 7 Permanent magnet 8 Caulking pin 9 Balance weight 10 End plate

Claims (4)

[Claims] A brushless motor for driving the compression element; a permanent magnet is provided in a rotor of the brushless motor; and a balance weight for balancing unbalance during rotation of the compression element is provided. An electric compressor fixed to at least one end of the rotor by a caulking pin penetrating the rotor, wherein an end plate formed of a non-magnetic material is interposed between the balance weight and the permanent magnet, and An electric compressor with caulking pins made of non-magnetic material. 2. The electric compressor according to claim 1, wherein the caulking pin is made of aluminum. 3. The electric compressor according to claim 1, wherein the end plate is made of brass. 4. The electric compressor according to claim 1, wherein the balance weight is formed of an iron plate.