JPH07117055B2 - Scroll type compressor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor used in a refrigeration cycle or the like, and particularly to prevention of liquid compression.

2. Description of the Related Art A conventional configuration will be described with reference to FIGS. 1 is a closed casing, 2 is an electric motor part, and a block is on the upper part.
3, a machine unit main body 7 including a fixed scroll 4, an orbiting scroll 5, and a rotation preventing mechanism 6 is fixed. The fixed scroll 4 is formed of an end plate 4a and an involute standing upright on the end plate 4a or a curved line similar to the involute, and is composed of a wrap 4b having a uniform thickness and height.
It is fixed to block 3 at. The orbiting scroll 5 is composed of an end plate 5a and a wrap 5b which is upright on the end plate 5a and has the same curve as the wrap 4b of the fixed scroll 4.
5a is sandwiched and supported via the end plate 4a of the fixed scroll 4 and the clearance A in the block 3, and is restrained by a rotation preventing mechanism 6 called an Oldham mechanism. And the fixed scroll 4 and the orbiting scroll 5 are
The winding end ends 4b 'and 5b' of the respective wraps 4b and 5b are fitted together with a certain angle offset.

Reference numeral 8 is a discharge hole, and 9 is a suction hole. The discharge hole 8 is provided at the center of the involute of the fixed scroll 4, and the suction hole 9 is provided at the outer edge of the end plate 4a of the involute of the fixed scroll 4. It communicates with chamber 9a. Reference numeral 10 denotes a protrusion provided on the surface of the orbiting scroll 5 opposite to the wrap 5b, which is concentric with the center of the involute of the wrap 5b. Reference numeral 11 denotes a shaft supported by the block 3, and the projection 10 of the orbiting scroll 5 is housed in a boss portion 11a which is provided at an end portion on the machine unit body 7 side and is eccentric from the shaft center. Are connected. Further, 11b is an oil supply passage, which communicates the boss portion 11a with the lower portion of the closed casing 1. Reference numeral 12 is a back pressure chamber formed on the back surface of the orbiting scroll 5, and communicates with the wrap 5b side of the orbiting scroll 5 via a clearance A. Further, 15 is a compression space. 16 is an orbiting scroll end plate 5a
And a thrust bearing provided between the block 3 and the block 3. A suction pipe 17 communicates with the suction hole 9. 18 is a discharge pipe.

Next, the compression mechanism of the scroll compressor will be described.

The rotational movement of the shaft 11 due to the rotation of the electric motor unit 2 is transmitted to the orbiting scroll 5 via the boss portion 11a and the protruding portion 10, but the orbiting scroll 5 does not rotate by the action of the rotation preventing mechanism 6 and does not rotate. A turning motion is performed with the center of the involute of 4 as the turning center. At this time, the winding end 5b 'of the wrap 5b of the orbiting scroll 5 is in contact with the wrap 4b of the fixed scroll 4, and the winding end 4b' of the wrap 4b of the fixed scroll 4 is in contact with the wrap 5b of the orbiting scroll 5. Is completed, and as the orbiting scroll 5 revolves, the pressure in the compression space 15 increases as the two contact points between the wraps 4b and 5b approach the center of the involute.

By the compression mechanism of this scroll compressor, the refrigerant sucked from the suction pipe 17 into the suction chamber 9a through the suction hole 9 is compressed and once discharged into the closed casing 1 through the discharge hole 8, and then the discharge pipe 18 Is discharged to a cooling system (not shown) via the. Further, the thrust force for separating the fixed scroll 4 and the orbiting scroll 5 in the axial direction due to the increase in the pressure of the compression space 15 is, for example, a thrust bearing such as a ball.
The back pressure chamber 12 supported by 16 communicates with the suction chamber 9a via the clearance A, and thus is maintained at the suction pressure.

Problems to be Solved by the Invention In such a conventional method, when the liquid refrigerant of the cooling system flows into the suction chamber through the suction hole at the initial stage of startup, the liquid refrigerant flows into the compression chamber because the volume of the suction chamber is small. As a result, abnormal pressure rise due to liquid compression occurred, and the end plates and wraps of the orbiting and fixed scrolls were sometimes broken or damaged. Further, in order to avoid this, the suction pipe and the back pressure chamber and the back pressure chamber and the suction chamber are communicated in order, and the sucked liquid refrigerant or gas refrigerant once flows into the large back pressure chamber and then reaches the suction chamber. There is also a method of taking a route to prevent liquid compression, but in this case the gas refrigerant that was sucked in will be sucked into the back pressure chamber even during steady operation, and will be affected by heat from the block etc. inside the back pressure chamber. Therefore, there is a problem that the heat receiving loss of the intake gas is increased or the volumetric efficiency is deteriorated. Incidentally, these problems occurred regardless of the presence or absence of the check valve.

The present invention solves the above-mentioned problems of the conventional example, in which a part of the refrigerant sucked from the suction pipe is guided to the suction chamber and a part thereof to the back pressure chamber at the same time, so that the volume efficiency is good. Another object of the present invention is to improve the reliability of scroll parts by guiding a part of the liquid refrigerant to the back pressure chamber even when the liquid refrigerant flows in through the suction pipe to reduce the frequency and time of liquid compression.

Means for Solving the Problems The present invention is provided with a communication passage that simultaneously connects the suction hole with the back pressure chamber and the suction chamber.

Action The present invention has the above-described configuration, and a part of the refrigerant sucked from the suction pipe is guided to the suction chamber and a part of the refrigerant is guided to the back pressure chamber, so that the refrigerant sucked from the cooling system is directly guided to the suction chamber. In comparison with, the back pressure chamber functions as a buffer chamber when the liquid refrigerant is sucked, and the frequency and time of liquid compression are reduced,
Since not all the refrigerant is introduced into the back pressure chamber as compared with other conventional examples in which all the intake gas is first introduced into the back pressure chamber and then introduced into the suction chamber, heat transfer from the block and the like is small and therefore the intake gas This has the effect of reducing the volumetric efficiency due to the heating.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3. Incidentally, the same parts as those of the conventional one are designated by the same reference numerals and the description thereof will be omitted. The arrows in the figure indicate the flow direction of the drawn refrigerant.

Reference numeral 19 denotes a suction hole, which communicates with the suction pipe 17. Reference numeral 20 denotes a communication passage, which is formed by partially cutting out the end plate 4a of the fixed scroll so that the suction hole 19 and the suction chamber 9a communicate with each other, and the suction hole 19 and the back pressure chamber 12 are connected via the communication passage 20. Are in communication.

In the above-mentioned configuration, the refrigerant sucked from the suction pipe 17 reaches the communication passage 20 through the suction hole 19, part of which is directly sucked into the suction chamber 9a and part of which reaches the back pressure chamber 12. The refrigerant that has entered the back pressure chamber 12 reaches the suction chamber 9a from the entire circumference through the clearance A between the orbiting and fixed scroll end plates 5a, 4a, and enters the same compression stroke as in the conventional case. Further, even when the liquid refrigerant flows in at the time of start-up, a part of the liquid refrigerant reaches the back pressure chamber 12 through the communication passage 20. Therefore, the amount of the refrigerant directly sucked into the suction chamber 9a is reduced as compared with the conventional case, and the frequency of liquid compression and the liquid compression time are reduced as compared with the conventional case. Further, even during steady operation, a part of the suction gas is always sucked directly into the suction chamber 9a, so that heat is not transferred from the block or the like as compared with the case where all the suction gas is sucked into the back pressure chamber 12 once. There is little decrease in volumetric efficiency due to heating of suction gas.

FIG. 4 shows another embodiment. 21 is spring 21a, valve 21
The check valve mechanism is composed of b and is housed in the suction hole 19. During operation, the suction chamber 9a becomes lower than the suction pipe internal pressure, the valve 21b moves in the direction of compressing the spring 21b, the suction hole 19 and the communication passage 20 communicate with each other, and the communication passage 20 communicates with each other. Refrigerant is drawn in. When stopped, the suction chamber 9a has a high pressure, so that the valve 21b moves toward the suction pipe 17 and is sealed by the end face of the suction pipe 17 and the valve 21b to prevent reverse rotation. Therefore, in addition to the conventional effect, the effect of preventing reverse rotation is added.

In the above description, the case where the suction pipe is provided in the radial direction has been described, but even when the suction pipe is provided in the axial direction, part of the suction gas is made into the suction chamber and part is made to the back pressure chamber by the communication passage. It goes without saying that the effects equivalent to those of the embodiment will be obtained if they are simultaneously led.

EFFECTS OF THE INVENTION As is apparent from the above description, according to the present invention, two orbiting and fixed scrolls which are upright on the end plate and which mesh with each other, a block which fixes the fixed scroll, and a rotation which prevents rotation of the orbiting scroll and performs a turning motion. A prevention mechanism, a suction hole that is opened in the fixed scroll and communicates with a suction pipe, a suction chamber formed on the outer peripheral side of the orbiting and fixed scroll, and a back pressure chamber formed by the end plate and block of the orbiting and fixed scroll. Since the suction hole and the back pressure chamber and the communication passage that simultaneously communicates the suction chamber are provided, part of the refrigerant sucked from the suction pipe is guided to the suction chamber, and part of the refrigerant is guided to the back pressure chamber. When the liquid refrigerant is sucked in, the back pressure chamber functions as a buffer chamber to reduce the frequency and time of liquid compression, and since not all the refrigerant is put in the back pressure chamber, the heat from the block etc. Since the amount of exchange is small, there is an effect that the volumetric efficiency is not lowered by heating the suction gas. In addition, a check valve is housed in the suction hole to add the effect of preventing reverse rotation.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a scroll type compressor showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a suction hole portion in FIG. 1, and FIG. 3 is a III-III 'line in FIG. FIG. 4 is an enlarged sectional view of a suction hole portion in another embodiment, FIG. 5 is a vertical sectional view of a conventional scroll compressor, and FIG. 6 is a sectional view of FIG.
FIG. 6 is a sectional view taken along line VI-VI ′. 3 ... Block, 4 ... Fixed scroll, 4a ... Fixed scroll end plate, 4b ... Fixed scroll wrap, 5 ...
… Orbiting scroll, 5a… Orbiting scroll end plate, 5b…
… Wrap of orbiting scroll, 6… Rotation prevention mechanism, 9a…
… Suction chamber, 12 …… Back pressure chamber, 19 …… Suction hole, 20 …… Communication passage.

Claims (2)

[Claims] 1. Two orbiting and fixed scrolls having mutually upstanding wraps on a mirror plate, a block for fixing the fixed scroll, a rotation preventing mechanism for preventing rotation of the orbiting scroll and performing a turning motion, and A suction hole that is opened in the fixed scroll and communicates with the suction pipe, a suction chamber formed on the outer peripheral side of the wrap of the orbiting and fixed scroll, and a back pressure chamber formed by the end plate of the orbiting and fixed scroll and the block. And a communication passage that simultaneously connects the suction hole with the back pressure chamber and the suction chamber. 2. A scroll compressor according to claim 1, wherein the communication passage is opened and closed by a check valve housed in the suction hole.