JP2002364542A - Electrically driven compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrically driven compressor of a suction refrigerant cooling type, having a simple structure permitting a small size, a lighter weight and a lower cost. SOLUTION: A motor part M is installed on a top side in a top-to-bottom direction and a compressing mechanism C is on a bottom side for operation. Thus, a refrigerant containing a lubricant flows from the motor part M on the upper side to the compressing mechanism C on the lower side and all flows into the compressing mechanism C without being left in the motor part M, therefore achieving a structure of lubricating the compressor without providing a special oiling mechanism. The need for a conventional lubricant reserving part and the oiling mechanism leading to a complicated structure is eliminated and so the electrically driven compressor has a simple structure permitting a smaller size, a lighter weight and a lower cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric compressor of a suction refrigerant cooling type for sucking a gas refrigerant from a motor part side to cool the motor part, and more particularly to a refrigerant pressure on a high pressure side which is a critical pressure of the refrigerant. As an electric compressor applied to the supercritical refrigeration cycle described above, the present invention is effectively applied to a heat pump water heater or the like employing a supercritical heat pump cycle using carbon dioxide as a refrigerant.

[0002]

2. Description of the Related Art Conventionally, in a vertically mounted electric compressor used for a refrigeration cycle of an air conditioner, a water heater, or the like, a lubricating oil reservoir is provided at a lower portion of a closed container and lubricating oil accumulated there is provided for lubrication of the compressor. And a lubrication mechanism for feeding the lubrication target part.

[0003]

However, the provision of the lubricating oil reservoir makes the electric compressor large (high). Further, it is necessary to vertically form the lubricating oil supply passage in the shaft, and to form the lubricating oil return passage in the housing, which complicates the structure and raises the processing cost.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a simple structure capable of reducing the size and weight and reducing the cost of an electric compressor of a suction refrigerant cooling system. It is in.

[0005]

In order to achieve the above object, the present invention employs the following technical means.

According to the first aspect of the present invention, the motor unit (M)
And the compression mechanism (C) is installed and operated as a top side in the top and bottom direction.

Accordingly, the refrigerant containing the lubricating oil flows from the upper motor section (M) to the lower compression mechanism section (C),
Since all of the oil flows into the compression mechanism (C) without remaining in the motor (M), the compressor can be lubricated without providing a special oil supply mechanism. As a result, the conventional lubricating oil reservoir and the conventional oil supply mechanism with a complicated structure can be eliminated, and the electric compressor can have a simple structure capable of reducing the size and weight and reducing the cost.

According to the second aspect of the present invention, the closed container (1
0) is filled with a low-pressure suction gas refrigerant before compression,
The compression mechanism (C) is characterized in that the discharge chamber (25) which becomes high in pressure with the discharged gas refrigerant after compression is surrounded by a low-pressure suction gas refrigerant atmosphere.

As a result, the discharge chamber (25) in the high-pressure gas atmosphere is surrounded by the low-pressure gas atmosphere, and there is no portion in contact with the atmospheric pressure. Can reduce the pressure resistance only by the pressure difference from the low-pressure gas, and can reduce the thickness of the housing.

In addition, since all parts in contact with the atmospheric pressure are in a low-pressure gas atmosphere, it is easy to secure the pressure resistance of the sealed container (10), so that the electric compressor can be reduced in size and weight and cost can be reduced. It can be structured.

This is particularly advantageous in an electric compressor used in a supercritical refrigeration cycle using carbon dioxide as a refrigerant, in which the high-pressure side pressure is higher by 2 to 5 times or more than that in a refrigeration cycle using chlorofluorocarbon as a refrigerant. To demonstrate.

According to the third aspect of the present invention, the motor section (M)
An electric terminal (40) for supplying electric power to the motor (30) housed in the airtight container (10) is provided on the top surface side of the closed container (10), and an outer terminal portion (41b) of the electric terminal (40).
After the external lead wire (42) is connected to the connector, the connection portion is sealed with a filler (P).

Conventionally, in an electric compressor of a suction refrigerant cooling system in which gas refrigerant is sucked from the motor section (M) side, if the electric terminal (40) is provided on the motor section (M) side, the electric terminal (40) is also reduced. The cooling mechanism is provided on the side of the compression mechanism (C) where the temperature becomes high due to the short circuit caused by dew condensation. However, even if the electric terminal (40) is provided on the compression mechanism (C) side, the possibility of dew condensation remains and reliability is low.

In addition, a passage for passing a lead wire is provided in the compression mechanism section (C) to be provided on the compression mechanism section (C) side, or an electric terminal (4) is provided on the cylindrical surface of the sealed container (10).
The provision of the seat 0) is complicated and the workability is poor. Also,
The workability of assembling is poor due to welding of the electric terminals (40) to the cylindrical surface and routing of the lead wires, etc., which causes a cost increase. In addition, the position of the connecting portion is limited by the outer surface of the cylinder or the like.

On the other hand, there is an example in which an electric terminal (40) is provided on the motor section (M) side and a rubber bush is attached to the lead wire to seal the lead wire outlet. However, dew condensation cannot be completely prevented. The problem remains.

However, according to the above invention, the electric terminal (40)
Is provided on the motor part (M) side, the outer connection part is completely sealed by sealing with the filler (P), so that the structure has high reliability against dew condensation. Also, this allows the electric terminals (4) to be placed on the top surface of the closed container (10) close to the motor (30).
0) can be arranged, and workability, assembling workability, and installability can be improved, so that the electric compressor can have a simple structure capable of reducing the size and weight and reducing the cost.

By the way, the reference numerals in parentheses of the above-mentioned means are examples showing the correspondence with the concrete means described in the embodiments described later.

[0018]

Next, embodiments of the present invention will be described with reference to the drawings.

In this embodiment, an electric compressor (hereinafter, abbreviated as a compressor) according to the present invention is applied to a water heater using a supercritical heat pump cycle using carbon dioxide as a refrigerant. Is a schematic diagram of a water heater.

Reference numeral 100 denotes a compressor according to the present invention;
Reference numeral 0 denotes a water-refrigerant heat exchanger (hereinafter, referred to as a heater) that exchanges heat between high-temperature and high-pressure refrigerant discharged from the compressor 100 and water for supplying hot water (water supply). Note that the heater 200 has a counterflow heat exchanger structure in which the feedwater flow and the refrigerant flow are opposed to each other in order to improve the heat exchange efficiency between the feedwater and the refrigerant.

Reference numeral 300 denotes a decompressor for decompressing the refrigerant flowing out of the heater 200. This depressurizer 300 is of a fixed throttle type with a fixed opening like a capillary tube. Reference numeral 400 denotes a heat absorber (evaporator) that evaporates the refrigerant decompressed by the decompressor 300 and absorbs heat from the atmosphere, and 500 converts the refrigerant flowing out of the heat absorber 400 into a liquid-phase refrigerant and a gas-phase refrigerant. Compressor 100 separates only gas phase refrigerant
This is an accumulator that flows out to the suction side and stores excess refrigerant during the cycle.

Reference numeral 610 denotes a temperature setting panel (temperature setting means) for setting and inputting a desired hot water supply temperature by a user of the water heater.
620 is a temperature sensor (temperature detecting means) for detecting the refrigerant temperature on the refrigerant inlet side of the heater 200;
630 is a water pump for supplying water.

The rotational speeds of the compressor 100 and the water pump 630 are determined based on the temperature set on the temperature setting panel 610 and the temperature detected by the temperature sensor 620 in accordance with a preset program according to an electronic control unit (ECU) 600.
Is controlled by Further, in the outdoor unit of the water heater that accommodates these devices, the compressor 100 is installed in such a manner that the motor unit M is on the top side in the top and bottom direction and the compression mechanism C is on the ground side.

Next, the structure of the compressor 100 will be described with reference to the sectional view of FIG.

The compressor 100 is constructed by joining an upper casing 12 and a lower casing 13 also made of iron to both ends of a cylindrical casing 11 made of iron pipe by welding.
0 is formed. The interior is roughly divided into a compression mechanism section C for compressing the refrigerant and a motor section M for driving the compression mechanism section C.
Are arranged vertically.

The compression mechanism section C is a well-known scroll-type compression mechanism including an orbiting scroll 21 and a fixed scroll 22, and a compressor housing 20 for accommodating a movable portion such as the orbiting scroll 21. These are also made of iron, and after being combined, the compressor housing 20 and the fixed scroll 22 are fixed with bolts (not shown).

In the motor section M, a DC brushless motor 30 (hereinafter abbreviated as a motor) is housed. The motor 30 has a stator 31 composed of a stator core and windings.
And the magnet rotor 3 rotating in the stator 31
2 are provided.

One end of the rotor shaft 33 supporting the magnet rotor 32 in the longitudinal direction is connected to the orbiting scroll 21 through the compressor housing 20 and is rotatable by a radial bearing 34 fixed to the compressor housing 20. Is held. On the other hand, the other end of the rotor shaft 33 is connected to the motor housing 3.
5, and is rotatably held by a radial bearing 36 fixed thereto.

The upper casing 12 is provided with an electric terminal 40 for supplying electric power to the motor 30. FIG. 3 shows the structure of the electric terminal section 40. An electric terminal 41 is fixedly welded to the upper casing 12, and a lead wire 37 from the motor 30 is connected to an inner terminal portion 41a of the electric terminal 41. An external lead wire 4 for connecting to a control power supply (not shown) is provided on the outer terminal portion 41b.
2 are connected.

A ring 43 is press-fitted and fixed to the upper casing 12 around the connection between the outer terminal 41b and the external lead wire 42 so as to surround the connection.
After the connection operation is completed, a filler P such as an epoxy resin is poured and molded (sealed) to completely waterproof the connection portion.

The external lead wire 42 protruding from the molded portion is fixed by a resin clamp 45 attached to the tip of a plate 44 screwed and fixed to a ring 43, and the external lead wire 42 is applied to the molded portion by a stress applied to the external lead wire 42. Cracks and the like are prevented from causing insulation failure.

Next, the flow of the gas refrigerant will be described.

The accumulator 5 is provided in the upper casing 12.
A suction port 14 for introducing the refrigerant flowing out of 00 into the closed container 10 is formed. The gas refrigerant is sucked into the closed container 10 from the suction port 14, and the sucked low-pressure gas refrigerant is
The refrigerant enters the suction chamber 24 via a refrigerant passage (not shown) formed between the stator 31 and the inner wall of the cylindrical casing 11 and a refrigerant passage (not shown) formed in the compressor housing 20.

The low-pressure gas refrigerant passes through a refrigerant passage (not shown) formed between the fixed scroll 22 and the inner wall of the cylindrical casing 11 to a space 26 between the fixed scroll 22 and the lower casing 13. Is also supplied.

The gas refrigerant entering the suction chamber 24 is compressed between the scrolls 21 and 22 to become a high-pressure gas refrigerant.
The liquid is discharged to a discharge chamber 25 formed by the fixed scroll 22 and the plate 23, and discharged from the discharge port 27, which communicates with the outside from the discharge chamber 25, to the outside of the compressor (heater 200).

Next, the features of this embodiment will be described.

The motor section M is installed on the top side in the up-down direction, and the compression mechanism section C is installed and operated on the ground side. This allows
Since the refrigerant containing the lubricating oil flows from the upper motor section M to the lower compression mechanism section C, and flows into the compression mechanism section C without remaining in the motor section M, the compressor can be operated without providing a special oil supply mechanism. It has a lubricating structure. For this reason, the conventional lubricating oil reservoir and the oil supply mechanism that complicates the structure are eliminated, and the electric compressor has a simple structure capable of reducing the size and weight and reducing the cost.

The inside of the closed vessel 10 is filled with the low-pressure suction gas refrigerant before compression, and the discharge chamber 25 of the compression mechanism C, which is high in pressure by the discharge gas refrigerant after compression, is surrounded by the low-pressure suction gas refrigerant atmosphere. It has a structure. This allows
The discharge chamber 25, which is a high-pressure gas atmosphere, is surrounded by a low-pressure gas atmosphere, and there is no part in contact with the atmospheric pressure. Only the pressure resistance can be reduced, and the thickness of the housing can be reduced.

Further, since all parts in contact with the atmospheric pressure are in a low-pressure gas atmosphere, it is easy to secure the pressure resistance of the sealed container 10. Therefore, the electric compressor has a simple structure capable of reducing the size and weight and reducing the cost. I have.

This is particularly effective in an electric compressor used for a supercritical refrigeration cycle using carbon dioxide as a refrigerant, which has a high pressure on the high side of 2 to 5 times or more as compared with a refrigeration cycle using chlorofluorocarbon as a refrigerant. Is showing.

The motor 30 accommodated in the motor section M
Terminal 40 for supplying power to the closed container 10
After the external lead wire 42 is connected to the outer terminal portion 41b of the electric terminal portion 40, the connection portion is molded with the filler P.

Thus, the electric terminal section 40 is connected to the motor section M
Even if it is provided on the side, the outer connection portion is completely waterproofed by being molded (sealed) with the filler P, and has a highly reliable structure against dew condensation. In addition, the motor 3
Since the electric terminal section 40 can be arranged on the top surface of the closed container 10 close to zero, and the workability, assembling workability, and installation property can be improved, the electric compressor can be reduced in size and weight and cost can be reduced. It has a structure.

(Other Embodiments) The present invention is not limited to the above-described embodiment, but can be modified or expanded as follows.

In the above-described embodiment, the scroll type compression mechanism is employed as the compression mechanism C. However, the electric compressor according to the present invention is not limited to this, and may be a vane type, a rotary piston (rolling piston) type, or the like. Other compression mechanisms may be used.

In the above embodiment, the motor 30 is a DC brushless motor. However, the present invention is not limited to this, and may be another electric motor such as an induction motor.

In the above embodiment, carbon dioxide is used as the refrigerant. However, the refrigerant used in the supercritical heat pump cycle is not limited to carbon dioxide, and may be, for example, ethylene, ethane, nitrogen oxide, or the like. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a water heater using an electric compressor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the electric compressor according to the embodiment of the present invention.

FIG. 3 is a detailed view of an electric terminal unit in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Closed container 25 Discharge chamber 30 Motor 40 Electric terminal part 41b Outer terminal part 42 External lead wire C Compression mechanism part M Motor part P Filling material

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Noritaka Akiyama 1-1-1, Showa-cho, Kariya-shi, Aichi F-term in DENSO Corporation (Reference) 3H003 AA01 AB04 AC03 BD01 BE00 CF02 CF03 3H029 AA02 AA13 BB00 BB12 BB32 CC02 CC07 CC09 CC27 CC56 CC62

Claims (3)

[Claims] 1. A compression mechanism (C) for sucking and compressing a refrigerant and a motor (M) for driving the compression mechanism (C) are connected in series in a closed container (10) through which the refrigerant flows. An electric compressor for supplying the refrigerant to the compression mechanism section (C) through the motor section (M), wherein the motor section (M) is set to the top side in the vertical direction and the compression mechanism section (C) An electric compressor, which is installed and operated as a ground side. 2. A discharge chamber (25) in which the inside of the closed container (10) is filled with a low-pressure suction gas refrigerant before compression, and a high-pressure discharge gas refrigerant of the compression mechanism (C) with the discharge gas refrigerant after compression.
2. The electric compressor according to claim 1, wherein the compressor is surrounded by the low-pressure suction gas refrigerant atmosphere. 3. An electric terminal section (40) for supplying electric power to a motor (30) housed in the motor section (M).
Is provided on the top side of the closed container (10), and an external lead wire (42) is connected to the outer terminal portion (41b) of the electric terminal (40). The electric compressor according to claim 1, wherein the compressor is sealed.