JPH11230075A - Sealed motor-driven compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand the operating condition range having a small refrigerant circulation quantity by opening a liquid injection valve via the action of an internal thermostat having a low operation set value, and stopping an electric motor via the action of an internal thermostat having a high operation set value. SOLUTION: When the temperature of the motor coil Mc of an electric motor M rises and reaches the operation set value of a second internal thermostat 32, the second internal thermostat 32 is operated to open a liquid injection valve 37, and a low-temperature liquid refrigerant is injected into a compression chamber 24 through a liquid injection circuit 36, the liquid injection valve 37 and a nozzle 38 to cool a scroll compression mechanism C. When the temperature of the motor coil Mc of the electric motor M continuously rises further and reaches the operation set value of a first internal thermostat 31, the first internal thermostat 31 is operated to stop the electric motor M.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hermetic electric compressor suitable for being incorporated in an air conditioner.

[0002]

2. Description of the Related Art One of conventional closed electric scroll compressors.
An example is shown in FIG. The closed housing 8 includes a cylindrical main body 8a, an upper head plate 8b and a lower head plate welded thereto. A scroll-type compression mechanism C and an electric motor M for driving the scroll-type compression mechanism C are built in the closed housing 8, and these are linked to each other via a rotating shaft 5.

The electric motor M includes a stator Ma and a rotor Mb. The stator Ma is fixed to a sealed housing 8, and the rotor Mb is fixed to a rotating shaft 5.

The scroll-type compression mechanism C comprises a fixed scroll 1, an orbiting scroll 2, a rotation preventing mechanism 3 such as an Oldham link for allowing its orbital orbiting motion to prevent its rotation, a frame 6, and the like.

The fixed scroll 1 has an end plate 11 and a spiral wrap 12 erected on the inner surface thereof. The end plate 11 is provided with a discharge port 13 and a discharge valve 47 for opening and closing the discharge port 13. The lift of the discharge valve 47 is regulated by a retainer 48, and one end of each of the discharge valve 47 and the retainer 48 is fastened to the end plate 11 by a bolt 49.

The closed housing 8 is partitioned into a discharge chamber 44 and a low-pressure chamber 28 by bringing the outer peripheral surface of the fixed scroll 1 into close contact with the inner peripheral surface of the main body 8a via an O-ring 89 embedded therein. .

The orbiting scroll 2 includes an end plate 21 and a spiral wrap 22 erected on the inner surface of the end plate 21. A drive bush 54 has a orbiting bearing 73 in a boss 23 projecting from the center of the outer surface of the end plate 21. It is fitted so as to be rotatable via the connector. A rotary shaft 5 is provided in a slide groove 55 formed in the drive bush 54.
An eccentric drive pin 53 projecting from the upper end of the slidably fitted therein.

[0008] A plurality of compression chambers 24 are formed by eccentrically interlocking the fixed scroll 1 and the orbiting scroll 2 by a predetermined distance and shifting the phase by 180 degrees.

The fixed scroll 1 is fastened to the frame 6 which is press-fitted and fixed in the sealed housing 8, and the rotation preventing mechanism 3 is interposed between the frame 6 and the outer peripheral edge of the outer surface of the end plate 21 of the orbiting scroll 2. ing.

The upper end of the rotating shaft 5 is supported on the frame 6 via an upper bearing 71, and the lower end of the rotating shaft 5 is supported by a lower bearing 72. The lower bearing 72 is supported by a stay 15 fixed to a lower portion inside the closed housing 8.

By driving the electric motor M, the rotating shaft 5, the eccentric drive pin 53, the drive bush 54, the slewing bearing
73, the orbiting scroll 2 is driven via the boss 23, and the orbiting scroll 2 revolves orbiting while being prevented from rotating by the rotation preventing mechanism 3.

Then, the refrigerant gas flows through the suction pipe 82 to the low pressure chamber.
The gas enters the compression chamber 24 through a gas passage (not shown). Then, as the volume of the compression chamber 24 decreases due to the orbital movement of the orbiting scroll 2, the compression chamber 24 is compressed and reaches the center chamber while being compressed, pushes and opens the discharge valve 47 from the discharge port 13 to enter the discharge chamber 44, and from there. It is discharged through the discharge pipe 83.

At the same time, oil in an oil sump 81 formed at the bottom of the sealed housing 8 is sucked up by an oil pump 51 and passes through an oil supply hole 52 to turn the bearing 73, the upper bearing 71, the lower bearing 72, and the rotation preventing mechanism 3. , The drive bush 54, the eccentric drive pin 53 and the like are lubricated.

[0014]

In the above-mentioned conventional hermetic compressor, when an excessive current flows through the electric motor M, the electric motor M is stopped. There was a problem that it could not be reliably prevented, and therefore the reliability was poor.

[0015]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its gist is that a compression mechanism and an electric motor for driving the compression mechanism are housed in a closed housing. In the hermetic electric compressor, first and second internal thermos whose operation set values are different from each other are embedded in a motor coil of the electric motor,
A hermetically closed electric compressor, wherein the liquid injection valve is opened by operation of the first internal thermo having a low operation set value, and the electric motor is stopped by operation of the second internal thermo having a high operation set value. On the machine.

Another feature is that an output end of each winding of the electric motor is connected to a connector fixed to the sealed housing, and the first and second internal thermos are connected to the winding of the electric motor. The output terminals are connected to the connector in parallel.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is shown in FIG. 1, wherein (A) is a system diagram and (B) is an electric circuit diagram. A first internal thermo 31 having a higher operation set value and a second internal thermo 32 having a lower operation set value are embedded in the motor coil Mc of the electric motor M.

The gas refrigerant discharged from the discharge pipe 83 of the hermetic electric scroll compressor is condensed in the condenser 33, then adiabatically expanded by being throttled by the expansion valve 34, and then evaporated in the evaporator 35. Is sucked from the suction pipe 82 into the low-pressure chamber 28.

When the liquid injection valve 37 is opened, the condenser
The low-temperature liquid refrigerant flowing out of 33 is injected into the liquid injection circuit.
The fuel is injected into the compression chamber 24 of the scroll compression mechanism C via the liquid injection valve 37 and the nozzle 38 interposed therebetween to cool the compression mechanism C.

As shown in (B), the first internal thermo 31 is connected in parallel with the V-phase winding of the electric motor M,
The second internal thermo 32 is connected in parallel with the W-phase winding of the electric motor M.

The output terminals U, V and W of the U-phase, V-phase and W-phase windings of the electric motor M, the output terminal A of the first internal thermo 31 and the output of the second internal thermo 32 The end B is taken out through the connector 39.

The output terminal A of the first internal thermo 31 is connected to a switch (not shown) of the electric motor M,
The output end B of the second internal thermo 32 is connected to the relay of the liquid injection valve 37.

The motor coil Mc of the electric motor M
When the temperature of the second internal thermo 32 rises and reaches the operation set value of the second internal thermo 32, the liquid injection valve 37 is opened by operating the second internal thermo 32, and the low-temperature liquid refrigerant is supplied to the liquid injection circuit 36. The liquid is injected into the compression chamber 24 through the liquid injection valve 37 and the nozzle 38 to cool the scroll compression mechanism C.

Despite this, when the temperature of the motor coil Mc of the electric motor M continues to rise and reaches the operation set value of the first internal thermo 31, the first internal thermo 31 is activated. As a result, the switch of the electric motor M is turned off, and the electric motor M stops.

[0025]

According to the present invention, the first and second internal thermos whose operation set values are different from each other are embedded in the motor coil of the electric motor, and the first internal thermo whose operation set value is low is operated by the operation of the first internal thermo. Opening the injection valve and stopping the electric motor by the operation of the second internal thermostat, which has a high operation set value, can extend the operating condition range where the amount of circulating refrigerant is small, and reduce the reliability of the hermetic electric compressor at low cost. Performance can be improved.

The output terminals of the respective windings of the electric motor are connected to a connector fixed to the sealed housing, and the first and second internal thermos are connected in parallel with the windings of the electric motor to connect these output terminals to the connector. Can reduce the number of terminals of the connector.

[Brief description of the drawings]

1 shows an embodiment of the present invention, (A) is a system diagram, (B)
Is an electric circuit diagram.

FIG. 2 is a longitudinal sectional view of a conventional hermetic electric compressor.

[Explanation of symbols]

 8 Closed housing C Compression mechanism M Electric motor Mc Motor coil 31 First internal thermo 32 Second internal thermo 33 Condenser 34 Expansion valve 35 Evaporator 36 Liquid injection circuit 37 Liquid injection valve U, V, W Electric motor Output terminal of M winding A Output terminal of first internal thermo B Output terminal of second internal thermo

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Masahiko Hirose 60, Iwatsukacho, Nakamura-ku, Nagoya-shi

Claims (2)

[Claims] 1. A hermetic electric compressor in which a compression mechanism and an electric motor for driving the compression mechanism are housed in a hermetically sealed housing, wherein the motor coils of the electric motor have first and second interfaces having different operation set values. A liquid injection valve is opened by operating a first internal thermo having a low operation set value, and the electric motor is stopped by operating a second internal thermo having a high operation set value. And hermetic electric compressor. 2. An output end of each winding of the electric motor is connected to a connector fixed to the closed housing, and the first and second internal thermos are connected in parallel with the winding of the electric motor. 2. The hermetic electric compressor according to claim 1, wherein an output end of the compressor is connected to the connector.