JPH0461200B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a scroll compressor used in a refrigeration cycle or the like, and particularly relates to the treatment of thrust force generated by compression.

Configuration of a conventional example and its problems First, the compression principle of a scroll type compressor will be explained with reference to FIG. In FIG. 3, 1a is a fixed scroll wrap, 2a is an orbiting scroll wrap, and 3 is a discharge hole.

In FIG. 3a, the combination of fixed and orbiting scroll wraps 1a, 2a forms a sealed fluid pocket 4. As the orbiting scroll 2 revolves around the center of the fixed scroll 1 with a radius _r0 , the fluid pocket 4 moves to the center as shown in figures b and c, reducing its volume, and as shown in figure d. The pressure reaches the highest level and is discharged from the discharge hole 3 to perform a fluid compression action.

Therefore, a force (hereinafter referred to as thrust force) that tends to separate the orbiting scroll 2 from the fixed scroll 1 is applied to the orbiting scroll 2 due to the pressure within the fluid pocket 4. In order to operate a scroll compressor reliably,
Some mechanical means is required to resist this thrust force.

For the above reasons, the conventional structure was as shown below. The conventional configuration will be explained using FIG. 4.

5 is a sealed casing, 6 is an electric motor section, and a mechanical section main body 9 consisting of a block 7, a fixed scroll 1, an orbiting scroll 2, and an anti-rotation mechanism 8 is fixed to the upper part thereof. Fixed scroll 1
is formed of an end plate 1b and an involute standing upright on the end plate 1b, or a curve similar to an involute, and has a uniform thickness and height, and is fixed to the block 7 by the end plate 1b. The orbiting scroll 2 is composed of an end plate 2b and a lap 2a that stands upright on the end plate 2b and has the same curve as the wrap 1a of the fixed scroll 1. They are sandwiched and supported with a slight clearance, and are restrained by an anti-rotation mechanism 8.

3 is a discharge hole, 10 is a suction hole, and the discharge hole 3 is located in the center of the involute of the fixed scroll 1;
The suction hole 10 is provided at the outer edge of the involute end plate 1b of the fixed scroll 1. Numeral 11 is a projection provided on the opposite side of the wrap 2a of the orbiting scroll 2, and is concentric with the center of the involute of the wrap 2a. Further, the shaft 12 is supported by a thrust bearing 13 and a radial bearing 14 attached to the block 7, and a boss portion 12a, which is eccentric from the center of the shaft 12 provided at the end on the side of the machine body 9, is attached to the center of the orbiting scroll 2. The electric motor section 6 and the orbiting scroll 2 are housed in the protrusion 11.
are connected.

15 is the end plate 2 of the block 7 and the orbiting scroll 2
b and a back pressure chamber defined by condenser A
It communicates with the position where the pressure is reduced by the first pressure reducer B1 via the communication hole 16.

In addition, 17 is a balance weight, 18 is a suction pipe,
19 is a discharge pipe, 20 is an oil supply pipe, B2 is a second pressure reducer, and C is an evaporator.

Next, the operation in this configuration will be explained.

The refrigerant that has flowed into the suction chamber 21 from the suction pipe 8 is discharged from the discharge hole 3 into the sealed casing 5 by the aforementioned compression action, and flows from the discharge pipe 19 to the cooling system. Note that a part of the refrigerant discharged into the hermetic casing 5 also flows downward into the hermetic casing 5 through the passage 22 together with the oil, thereby making the inside of the hermetic casing 5 in a high pressure state.

Further, among the refrigerant flowing into the cooling system, a part of the refrigerant whose pressure has been reduced by the first pressure reducer B1 is transferred to the communication hole 16.
The pressure inside the back pressure chamber 15 is maintained at an intermediate pressure between the discharge pressure and the suction pressure.

When the inside of the back pressure chamber 15 reaches an intermediate pressure, an intermediate pressure acts on the back surface of the end plate 2b of the orbiting scroll 2, and a force suitable for resisting the thrust force generated by the compression action is generated, and the tip of the scroll member and the end plate The system maintains sufficient airtightness and performs highly efficient and reliable steady operation.

However, in the above configuration, at startup, the back pressure chamber 15
The internal pressure did not reach a sufficient pressure to resist the thrust force, and the end plate 2b of the orbiting scroll 2 was sandwiched and supported between the end plate 1b of the fixed scroll 1 and the pedestal part 7a of the block 7 with a small clearance. As a result, the head plate 2b tilts, and the shaft 12 hits one side, causing wear and seizure of the sliding parts, making it impossible to obtain a reliable compressor.

Purpose of the Invention The present invention has been made in view of the above points, and it is an object of the present invention to obtain a highly reliable and highly efficient compressor by applying an appropriate anti-thrust force to the back surface of the orbiting scroll not only during steady operation but also at startup. It is in.

Structure of the Invention To achieve this object, the present invention prevents seizure, wear, etc. by introducing discharge pressure during startup and intermediate pressure during steady operation into the back pressure chamber on the back of the orbiting scroll. This is how it was done.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Note that the same parts as those in the conventional example are given the same reference numerals, and the description thereof will be omitted.

23 is a valve mechanism disposed between the rear of the first pressure reducer B1 of the cooling system and the communication hole 16 of the back pressure chamber 15, and the casing 24 includes a spring 25 and a valve body 26. be. Also, in the casing 24,
An intermediate pressure communication pipe 27 communicating with the rear of the first pressure reducer B1;
high-pressure communication pipes 28, 29 communicating with the front of the condenser A;
A back pressure communication pipe 30 communicating with the communication hole 16 is provided. Further, the spring 25 is set to be weaker than the discharge pressure during normal operation and stronger than the balance pressure during stoppage.
Note that 31 is a communication hole provided in the valve body, and 32 is a pressure sensitive chamber.

Next, the operation of this configuration will be explained.

At startup, the valve mechanism 23 (in the state shown in FIG. 1) has a pressure inside the pressure sensitive chamber 32, which is the discharge pressure, which is still lower than the discharge pressure during steady operation, and the valve body is overcome by the restoring force of the spring 25. 26 is pressed to the left in the figure, the communication hole 31 communicates with the high pressure communication pipe 29, and the back pressure chamber 15
The pressure inside becomes the discharge pressure. Therefore, the end plate 2 provides a force to resist the thrust force generated by the compression action.
The pressure on the back side b becomes the discharge pressure, and the end plate 2b can be pushed up in the direction of the anti-thrust force with an appropriate force.
It is possible to prevent the tilting phenomenon of the mirror plate 2b.

Next, as time passes and steady operation is achieved, the valve mechanism 23
In the state shown in FIG. 2, the discharge pressure also becomes larger than the discharge pressure at startup, and the valve body 26 overcomes the spring force and is pushed to the right in FIG. 2, and the communication hole 31 communicates with the intermediate pressure communication pipe 27. , the pressure inside the back pressure chamber 15 becomes an intermediate pressure, and the minimum force necessary to resist the thrust force acts on the back surface of the head plate 2b, pushing the head plate 2b up with an appropriate force in the direction of the anti-thrust force, thereby preventing the tilting phenomenon. The tip of the wrap is kept airtight, resulting in highly efficient and reliable operation.

Effects of the Invention As is clear from the above description, the present invention provides a valve mechanism that introduces discharge pressure during startup and intermediate pressure during steady operation into the back pressure chamber on the back surface of the orbiting scroll. It is possible to prevent tilting of the surface, prevent seizure, wear phenomena, etc.
It also maintains airtightness at the tip of the wrap, resulting in a highly efficient and highly reliable compressor.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a scroll compressor showing an embodiment of the present invention, Fig. 2 is a cross-sectional view showing the operating state of the valve mechanism shown in Fig. 1, and Fig. 3 is the compression principle of the scroll compressor. In the explanatory diagrams, a to d are transition diagrams of the compression process, and FIG. 4 is a sectional view of a conventional scroll compressor. 1... fixed scroll, 1a... fixed scroll wrap, 1b... fixed scroll end plate, 2
...Orbiting scroll, 2a... Orbiting scroll wrap, 2b... Orbiting scroll end plate, 8...
Rotation prevention mechanism, 15... Back pressure chamber, 16... Communication hole, 23... Valve mechanism.

Claims (1)

[Claims] 1. A fixed scroll and an orbiting scroll having spiral wraps formed on the end plate are engaged with each other with the wraps inside, and an electric motor unit is provided for rotating the orbiting scroll with respect to the fixed scroll, and a motor unit is provided on the back surface of the orbiting scroll. A valve mechanism is provided with a communication hole for supplying fluid to the provided back pressure chamber, and the communication hole is configured to supply discharge pressure fluid during startup and supply pressure fluid intermediate between the discharge pressure and suction pressure during steady operation. Scroll type compressor.