High-pressure dome type compressor

• US 20020159890A1
• Filed: 11/14/2001
• Published: 10/31/2002
• Est. Priority Date: 03/31/2000
• Status: Active Grant

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Hirano, Masatoshi, Nojima, Nobuhiro, Ida, Kazuo, Kajiwara, Mikio, Deguchi, Ryohei, Komori, Keiji
• Granted Patent: US 6,652,238 B2
• Time in Patent Office: Days
• US Class Current: 417/32
• CPC Class Codes: F04C 2240/403 with inverter for speed control
• CPC Class Codes: F04C 28/08 characterised by varying the rotational speed
• CPC Class Codes: F04C 29/045 of the electric motor in hermetic pumps
• CPC Class Codes: Y10S 417/902 Hermetically sealed motor pump unit

Abstract

There is provided a high-pressure dome type compressor which comprises a motor using a rare earth magnet and has stable performance. There are provided a compression element 3 and a DC motor 5 for driving the compression element 3 in a casing 2. The motor 5 is disposed in a high pressure area 6, which obtains a high temperature and high pressure due to a discharged gas. The motor 5 includes a rare earth/iron/boron permanent magnet having an intrinsic coercive force of 1.7 MA/m⁻¹ or greater in a rotor and has a rated output or 1.9 kW or higher. An inverter 10 controls a current to be supplied to the motor 5 such that a temperature of the motor 5 becomes equal to a predetermined temperature or lower and that an opposing magnetic field generated in a stator of the motor 5 has a predetermined strength or less. Therefore, since the rare earth magnet of the motor 5 does not obtain a high temperature and is not exposed to a strong opposing magnetic field, the magnet is hardly demagnetized. Thus, performance of the motor 5 and further performance of the high-pressure dome type compressor 1 become stable.

Claims

1. A high-pressure dome type compressor comprising a compression element (3) and a motor (5) for driving the compression element (3) in a casing (2), the motor (5) being disposed in a high pressure area (6) filled with a gas discharged from the compression element (3) in the casing (2), characterized in that:

the motor (5) has a rated output of 1.9 kW or higher; and

a rotor (5a) of the motor (5) includes a rare earth/iron/boron permanent magnet (25) having an intrinsic coercive force of 1.7 MA/m<sup>−

1</sup> or greater.

2. The high-pressure dome type compressor according to claim 1, further comprising:

a temperature sensor (15) for detecting a temperature of the motor (5); and

first control means for, upon receipt of a signal from the temperature sensor (15), controlling a current to be supplied to the motor (5) such that the temperature of the motor (5) becomes equal to a predetermined temperature or lower.

3. The high-pressure dome type compressor according to claim 1, further comprising:

current detecting means for detecting a current flowing in the motor (5);

second control means for receiving a signal from the current detecting means and controlling a current to be supplied to the motor (5) such that an opposing magnetic field generated in the motor (5) becomes equal to a predetermined strength or less.

4. The high-pressure dome type compressor according to claim 1, wherein

a discharge pipe (8) for discharging the discharged gas from the casing (2) is disposed on a side of the motor (5) opposite from the compression element (3).

5. The high-pressure dome type compressor according to claim 1, wherein

a discharge pipe (8) is communicated with the high pressure area (6) between the compression element (3) and the motor (5), while the gas discharged from the compression element (3) passes through a path (21) in a crank shaft (4) and is discharged to the high pressure area (6) on a side of the motor (5) opposite from the compression element (3).

6. The high-pressure dome type compressor according to claim 1, wherein

the permanent magnet (25) for the rotor (5a) of the motor (5) is coated with aluminium.

7. A refrigerant unit comprising the high-pressure dome type compressor according to claim 1 and using R32 as a refrigerant.