JPH0281982A - Scroll compressor - Google Patents

Abstract

PURPOSE:To avoid liquid compression in the time of cold start of a compressor simplified in its constitution by providing a communication hold, connecting a suction chamber to communicate with the inside of a closed vessel, in a fixed scroll and a valve with a built-in shape memory alloy spring halfway the communication hole. CONSTITUTION:In the time of cold start with refrigerant gas dissolved in lubricating oil 21 in the bottom part of a closed vessel 10, its low internal temperature causes a piston 25 to be pressed to the side of a shape memory alloy spring 24 by urging force of a bias spring 26 fixed by a fixing screw 27 in a fixed scroll 1, so that a suction chamber 12 communicates with the inside of the closed vessel 10 through a communication hole 22. That is, a valve 23 with a built-in spring of shape memory alloy is opened, and liquefied refrigerant, reaching the suction chamber 12, is not compressed but guided in the closed vessel 10, avoiding liquid compression. Accordingly, the improvement of reliability can be contrived while preventing a motor from burning due to an overload.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a scroll compressor used as a refrigerant compressor for refrigeration and air conditioning, refrigerators, and the like.

Conventional technology The basic structure, lubrication method, etc. will be explained with reference to FIGS. 3 and 4. In addition, for ease of explanation, solid line arrows indicating the flow direction of the working gas and broken line arrows indicating the flow direction of the lubricating oil are shown as such.

FIG. 3 shows an overall configuration diagram of a conventional hermetic scroll compressor for an air conditioner. The compressor includes both scrolls, a fixed scroll 1 and an orbiting scroll 2, which are compression element parts, an anti-rotation member 3 that prevents rotation of the orbiting scroll 2, and a main shaft 4.
, consists of three bearing parts that support this, namely a swing bearing 6, a main bearing 6, an auxiliary bearing 7, an electric motor 8, and a block 9 of a stationary member that fixes the fixed scroll 1. These components are housed inside the closed container 10.

The operation of the compressor will be explained according to the flow of refrigerant gas and the flow of lubricating oil.

The low-temperature, low-pressure refrigerant gas is guided from the suction pipe 11 and reaches the suction chamber 12 within the fixed scroll 1 . As shown in FIG. 4, the refrigerant gas that has reached the compression element is moved into a closed space 13a formed by both scrolls due to the orbital movement of the orbiting scroll 2, which is prevented from rotating.

As the refrigerant gas 13b gradually contracts and moves to the center of the scroll, the pressure of the refrigerant gas is increased and the refrigerant gas is discharged from the central discharge hole 14. The discharged high-temperature, high-pressure refrigerant gas fills the space 18 around the electric motor via the 16° gap between the containers in the closed container 1o and the communication passages 16, 17, and is guided to the outside via the discharge pipe 19.

On the other hand, a back pressure chamber 2o, which is a space surrounded by the back surface of the orbiting scroll 2 and the block 9, has a back pressure chamber 2o that resists the gas force in the thrust direction due to the gas pressure in a plurality of sealed spaces formed by both the orbiting and fixed scrolls. Therefore, a pressure between suction pressure and discharge pressure acts. This intermediate pressure can be set between the discharge pressure and the suction pressure by providing the pores 2b and 2C in the end plate 2a of the orbiting scroll 2 at positions that communicate the suction chamber 12 and the back pressure chamber 20 of the fixed scroll 1. This is done by applying gas force to the back surface of the orbiting scroll 2.

Next, the flow of lubricating oil will be explained.

Lubricating oil 21 is stored in the lower part of the closed container 10.

The lower end of the main shaft 4 is immersed in the oil at the bottom of the container, and the upper part of the main shaft is provided with an eccentric shaft portion 4a.
is engaged with. For main shaft 4.

An eccentric vertical hole 4a for supplying oil to each bearing portion is formed from the lower end of the main shaft to the upper end surface of the main shaft. The lower end of the main shaft 4 immersed in the lubricating oil 21 is in an atmosphere of high discharge pressure (PD), while the area around the downstream swing bearing 5 is under intermediate pressure (
pm), the lubricating oil 21 at the bottom of the container rises in the vertical hole 4b due to the pressure difference (pd-pm).

The lubricating oil that has ascended through the vertical hole 4b is supplied to the auxiliary bearing, the main bearing 6, and the swing bearing 6, and is discharged to the back pressure chamber 20 through the respective bearing gaps. The lubricating oil that has reached the back pressure chamber 20 is injected into the suction chamber 12 of the fixed scroll 1 through the pores 2b and 2c, and mixed with the refrigerant gas. Next, the lubricating oil is pressurized together with the refrigerant gas, and the discharge hole 1
4. The discharge chamber 15 further moves to the electric motor chamber 18 via communication passages 16 and 17. The lubricating oil that has reached the motor chamber 18 falls to the bottom of the container 1o due to its own weight, is collected at the bottom of the container again, and is supplied to lubricate each part.

In the y-scroll compressor configured as above,
A suction chamber 12 in the fixed scroll 1 guided from the suction pipe 11
As shown in FIG. 4, the refrigerant gas reaches the point where the closed spaces 13a and 13b formed by both scrolls gradually shrink due to the orbital movement of the orbiting scroll 2, which is prevented from rotating.
As the refrigerant gas moves to the center of the scroll,
The pressure is increased and the liquid is discharged into the closed container 10 from the central discharge hole 14. Furthermore, the lubricating oil 21 at the bottom of the container that has reached the back pressure chamber 20 is injected into the suction chamber 12 of the fixed scroll 1 through the pores 2b and 2c and mixed with the refrigerant gas.

Problems to be Solved by the Invention However, in the above configuration, during cold start-up when the refrigerant gas is dissolved in the lubricating oil 21 at the bottom of the closed container 1o, the lubricating oil 21 containing liquid refrigerant flows into the back pressure chamber 20. As a result,
It is injected into the suction chamber 12 through the pores 2b and 2C, and mixes with the refrigerant gas led from the suction pipe 11, resulting in liquid compression, which places an excessive load on the motor and causes burnout of the motor due to overcurrent. It had a problem of 7.

The present invention solves these conventional problems and provides a scroll compressor that has a simple configuration and can avoid liquid compression during cold startup.

Means for Solving the Problems In order to solve the above-mentioned problems, the scroll compressor of the present invention has a communication hole in the fixed scroll that communicates the suction chamber with the inside of the closed container, and a shape memory in the middle of the communication hole. It is equipped with a valve with a built-in alloy spring.

According to the above-described configuration, the valve with a built-in shape memory alloy spring opens during cold startup to communicate the suction chamber with the inside of the sealed container to avoid liquid compression and prevent motor burnout due to overload. Can be done.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2. Note that the same parts as in the conventional example are given the same reference numerals, and the description thereof will be omitted. In FIG. 1, 22 is a communication hole that communicates between the suction chamber 12 and the inside of the closed container 10, and 23 is a valve with a built-in shape memory alloy spring provided in the middle of the communication hole. In FIG. 2, 24 is a shape memory alloy spring, 25 is a piston that opens and closes the communication hole 22, 26 is a bias spring that biases the piston 26 toward the shape memory alloy spring 24, and 27 is the bias spring 2e. Tighten with the fixing screw to secure it.

In the above configuration, when the refrigerant gas is dissolved in the lubricating oil 21 at the bottom of the closed container 1o and the closed container 1o is started, the closed container 1o
Since the temperature inside is low and the piston 25 is pressed toward the shape memory alloy spring 24 by the biasing force of the bias spring 26 fixed by the fixing screw 27 in the fixed scroll 1, the inside of the suction chamber 12 and the closed container 10 are is the communication hole 22
communicate via. That is, the shape memory alloy spring built-in valve 23 opens, and the liquid refrigerant that has reached the suction chamber 12 is guided into the closed container 10 without being compressed, thereby avoiding liquid compression.

In addition, during a temporary period including startup under heat, the temperature inside the closed container 10 is high and the shape memory alloy spring 24 inside the fixed scroll 1
expands 1 and presses the piston 26 toward the bias spring 26, so that the communication hole 22 is closed by the piston 25. That is, since the shape memory alloy spring built-in valve 23 is closed, the refrigerant that has reached the suction chamber 12 is not guided into the closed container 10 via the communication hole 22.

As described above, according to this embodiment, by providing the communication hole 22 that communicates between the suction chamber 12 and the inside of the closed container 1o, and the valve 23 with a built-in shape memory alloy spring in the middle of the communication hole 22, it is possible to The liquid refrigerant that has reached the suction chamber 12 is guided into the closed container 1o without being compressed, thereby avoiding liquid compression, preventing motor burnout due to excessive load, and improving reliability.

Effects of the Invention As described above, the present invention provides a communication hole that communicates between the suction chamber and the inside of the sealed container, and also provides a valve with a built-in shape-memory alloy spring in the middle of the communication hole, so that the suction chamber is closed during cold startup. The liquid refrigerant that has reached the temperature is guided into the sealed container without being compressed, thereby avoiding liquid compression, preventing motor burnout due to an oversized pipe, and improving reliability.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a scroll compressor showing an embodiment of the present invention, Fig. 2 is a cross-sectional view of the valve with a built-in shape memory alloy spring shown in Fig. 1, and Fig. 3 is a longitudinal cross-sectional view of a conventional scroll compressor. side view,
FIG. 4 is a cross-sectional view showing the meshing state of the scrolls. 1...Fixed scroll %2...Orbiting scroll, 2a...End plate, 10...Airtight container, 12...Suction chamber, 22 ...Communication hole, 23...Shape memory alloy (Built-in valve. Name of agent: Patent attorney Shigetaka Awano and one other person Fig. (-m-Fixed flow Ishi2- 10,000 foot 1 Yo scroll &---so negative-a to---ri d memi number, 12- inhalation e2-,,-1Ef1ako

Claims (1)

[Claims] A fixed scroll having a spiral wrap on an end plate in a closed container, an orbiting scroll having a spiral wrap on an end plate that engages with the wrap, and a suction chamber in the fixed scroll and the inside of the closed container in the fixed scroll. A scroll compressor characterized by having a communicating hole and a shape memory alloy spring built-in valve provided in the middle of the communicating hole.