JP2723610B2 - Two-stage compression rotary compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a two-stage compression type rotary compressor used for an air conditioner, a water heater, a refrigerator and the like.

2. Description of the Related Art In recent years, a two-stage compression type rotary compressor capable of increasing a condensing temperature has been considered in response to a demand such as an increase in a hot water temperature in a hot water supply device in an air conditioner or the like. For example, Japanese Patent Application Laid-Open No. Sho 62-29787
There is a stage compression type rotary compressor.

Problems to be Solved by the Invention However, the configuration of the conventional two-stage compression type rotary compressor has the following problems.

(1) The temperature rise of the motor unit that is not actively cooled becomes excessive, and the use load limit must be set.

(2) Although it was necessary to make the volume of the second-stage cylinder smaller than the volume of the first-stage cylinder, the configuration of the compressor section was not clarified, so that the processing was easy, the middle plate and the piston Problem of leakage loss from seal surface

The present invention has been made in view of the above problems, and provides a two-stage compression type rotary compressor that solves these problems.

Means for Solving the Problems In order to solve the above problems, the present invention provides a motor unit inside a closed container, a compressor unit having two compression chambers driven by the motor unit and performing two-stage compression, The first stage and the second stage cylinders are provided below the lower part, and the crankshaft eccentricity of both cylinders is the same, the height of the first stage cylinder is higher than that of the second stage cylinder, The compressed refrigerant is discharged into an airtight container above the electric motor unit and is branched so as to be discharged into an airtight container below the electric motor unit.

The present invention has a configuration in which the compressed refrigerant due to the first-stage discharge pressure is discharged into the closed container above the electric motor unit and is branched so as to be discharged into the closed container below the electric motor, thereby partially cooling the electric motor unit. The refrigerant which is not overheated mainly by the electric motor is sucked into the second stage cylinder.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a two-stage compression type rotary compressor according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an airtight container, 2 denotes a motor portion accommodated in the upper portion of the airtight container 1, and 3 and 4 denote a first-stage cylinder and a second-stage cylinder disposed below the electric motor portion 2, respectively. Reference numeral 5 denotes an intermediate plate located between the first-stage cylinder 3 and the second-stage cylinder 4 and fixed to the closed container 1. Reference numeral 6 denotes a lower bearing end plate, 7 denotes an upper bearing end plate, 8 denotes a crankshaft connecting the motor unit 2 and the compressor unit, 9 denotes a first-stage piston, and 10 denotes a second-stage piston. Reference numeral 11 denotes a first-stage suction pipe, and reference numeral 12 denotes a connection pipe that directly discharges the first-stage discharged refrigerant to the outside of the closed container 1, and is connected to an upper portion of the electric motor unit 2 of the closed container 1. Reference numeral 13 denotes a second-stage discharge pipe for directly discharging the second-stage discharged refrigerant to the outside of the closed container 1.

Reference numeral 15 denotes a valve cover for temporarily storing the first-stage discharged refrigerant, and reference numeral 16 denotes a communication hole that connects the inside of the valve cover 15 and the inside of the closed container 1.

As described above, the refrigerant is sucked from the first-stage suction pipe 11 with the rotation of the first-stage piston 9. The inhaled refrigerant is 1
After being compressed to the first stage discharge pressure by the third stage cylinder 3,
Closed container 1 above motor unit 2 through connecting pipe 12
It is discharged into. The discharged refrigerant cools the electric motor unit 2 and is sucked into the second-stage cylinder 4 from a second-stage suction hole formed in the upper bearing end plate 7. The sucked refrigerant of the first stage discharge pressure is compressed to the second stage discharge pressure, and the second stage discharge pipe
The liquid is discharged out of the closed container 1 through 13. On the other hand, the refrigerant compressed to the first-stage discharge pressure is discharged into the closed vessel 1 above the electric motor unit 2 through the connecting pipe 12, cools the electric motor unit 2, and is sucked into the second-stage cylinder. On the other hand, it is sucked into the second stage cylinder through the communication hole 16.

Therefore, since the first-stage discharge pipe is connected to the closed vessel above the motor unit by the connection pipe, there is an effect that the motor unit can be actively cooled by the first-stage discharge refrigerant. Further, since the motor section is cooled, the use load of the compressor can be limited more than a general two-stage compressor, and there is an advantage that the use range can be expanded.

In FIG. 1, the height of the first-stage cylinder 3 is higher than the height of the second-stage cylinder 4, and the eccentric portions 8A and 8B of the crankshaft 8 have the same eccentric amount. I have. Since the first stage cylinder volume and the second stage cylinder volume have the same amount of eccentricity of the crankshaft, the cylinder volume is proportional to the ratio of the respective cylinder heights.

That is, in the first-stage cylinder, the pressure in the hollow portion 21 of the middle plate 5 is the first-stage discharge pressure. Refrigerant leaks from the gap between the end face and the middle plate end face. 2
Conversely, in the second stage cylinder,
Refrigerant leaks into the hollow portion 21 of the middle plate 5 from the gap between the end face of the second-stage piston and the end face of the middle plate, resulting in pressure loss.

In order to reduce these leaks, it is necessary to increase the length of the leak passage. Generally, the length of the leak passage between the hollow portion 21 of the intermediate plate 5 and the inside of the cylinder decreases as the amount of eccentricity of the eccentric portion of the crankshaft 8 increases.

Therefore, as in the present embodiment, the crankshaft eccentricity of the first-stage and second-stage cylinders is the same, and the height of the first-stage cylinder is higher than the height of the second-stage cylinder. The second stage is larger than the second stage, so that appropriate two-stage compression can be performed. Further, since the amount of eccentricity of the crankshaft is the same in the first stage and the second stage, there is an advantage that processing is easy.

In addition, since the length of the leakage passage can be made the same as that of the first stage and the second stage with respect to the leakage from the intermediate portion of the middle plate 5, there is an advantage that the pressure loss due to the leakage loss can be reduced.

In addition, since the first-stage discharged refrigerant is branched into a flow path for discharging the refrigerant from the first-stage cylinder to the connecting pipe and a flow path for discharging the refrigerant into the closed vessel, the main motor unit is partially cooled while being mainly cooled. Since the refrigerant that is not overheated by the motor unit can be sucked into the second-stage cylinder through the communication hole, volume-efficient compression can be performed.

Effects of the Invention As is clear from the above, the following effects can be obtained by the present invention.

(1) Since the first-stage discharge pipe is connected to the closed vessel above the motor by the connection pipe, the motor section can be actively cooled by the first-stage discharge refrigerant. Further, since the motor section is cooled, the use load limit of the compressor can be set larger than that of a general two-stage compression type rotary compressor, and there is an advantage that the use range is expanded.

(2) A configuration in which the compressed refrigerant due to the first-stage discharge pressure is discharged into the closed container above the electric motor unit and branched so as to be discharged into the closed container below the electric motor unit, thereby partially cooling the electric motor unit. In addition, the refrigerant that is not overheated mainly by the electric motor unit can be sucked into the second-stage cylinder, and compression with good volumetric efficiency can be performed.

(3) By setting the height of the first-stage cylinder higher than that of the second-stage cylinder with the same amount of crankshaft eccentricity of both cylinders, the cylinder volume of the first-stage cylinder is larger than that of the second-stage cylinder, and A simple two-stage compression can be performed. In addition to ease of processing, compression loss has also been reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a two-stage compression type rotary compressor according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Closed container, 2 ... Electric motor part, 3 ... 1st cylinder, 4 ... 2nd cylinder, 5 ... Middle plate, 6 ... Lower bearing end plate, 7 ... Upper bearing end plate, 8 ... crankshaft, 9 ...
... First stage piston, 10 ... Second stage piston, 11 ... First stage suction pipe, 12 ... Connection pipe, 13 ... Second stage discharge pipe, 16 ...
Communication hole, 21 ... hollow part of middle plate.

Claims (1)

(57) [Claims] 1. A motor unit in a sealed container, a compressor unit driven by the motor unit and having two compression chambers for two-stage compression, and a first-stage and a second-stage cylinder below the motor unit. The first-stage cylinder height is made higher than the second-stage cylinder with the same amount of crankshaft eccentricity of the two cylinders, and the compressed refrigerant due to the first-stage discharge pressure is discharged into the closed container above the electric motor unit. And a two-stage compression type rotary compressor configured to be branched so as to be discharged into a closed container below the electric motor.