JPH0526002A - Scroll type fluid machine - Google Patents

Abstract

PURPOSE:To prevent breakage of a compression mechanism, and suppress any increase in prescribed horsepower of a compressor by forming a high pressure chamber, an intermediate pressure chamber, and a low pressure chamber on the back surface side of a fixed scroll or a turning scroll, and setting the area of the high pressure chamber to a specified value or less. CONSTITUTION:The lap 12 of a fixed scroll 1 is engaged with the lap 22 of a turning scroll 2 so as to form a plurality of enclosed spaces 24 point- symmetrically. The volume of each enclosed space 24 is changed in association with movement of a position where the lap 22 of the turning scroll 2 abuts on the lap 12 of the fixed scroll 1. Two points A, B are represented, wherein, both laps 12, 22 abut on each other at the inner most circumference thereof just after the inner most two enclosed spaces 24A, 24B pass each other. The area of the high pressure chamber is set in an area similar to that of circle whose diameter is equal to the distance between the points A and B, or it is set smaller than that area. Therefore, it is eliminated that any excessive back pressure load is applied to the fixed scrolled 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll type fluid machine.

[0002]

2. Description of the Related Art An example of a conventional scroll type compressor is shown in FIG.
Explaining the longitudinal sectional view, the interior of the closed housing 8 is partitioned into a high pressure side 44 and a low pressure side 45 by a discharge cover 31. Inside the low voltage side 45, a scroll type compression mechanism C is arranged at the upper part thereof, and an electric motor M is arranged at the lower part thereof, which are interlockingly connected to each other via a rotary shaft 5. The electric motor M is composed of a rotor Ma and a stator Mb, the rotor Ma is fixed to the rotating shaft 5, and the stator Mb is fixed by being press-fitted in the hermetic housing 8. The scroll type compression mechanism C has a fixed scroll 1 and an orbiting scroll 2. The fixed scroll 1 includes an end plate 11 and a spiral wrap 12 provided upright on the inner surface thereof.
A discharge port 13 is provided at the center of 1. The orbiting scroll 2 includes an end plate 21 and a spiral wrap 22 provided upright on the inner surface of the orbiting scroll 2. A drive bush 54 is provided in an orbiting bearing 73 in a boss 23 provided upright on the outer surface of the end plate 21.
This drive bush 5 is rotatably fitted and inserted through
An eccentric pin 53 projecting from the upper end of the rotary shaft 5 is slidably fitted in a slide hole 55 formed in the shaft 4. The fixed scroll 1 and the orbiting scroll 2 are eccentric with respect to each other by a predetermined distance, and are meshed with each other at an angle of 180 degrees to form a plurality of closed spaces 24. The orbiting scroll 2 is slidably supported on a casing 6 fixed in a hermetically sealed housing 8. The orbiting scroll 2 is allowed to revolve around the orbiting scroll 2 but prevents its rotation. A rotation prevention mechanism 3 including an Oldham link is provided. The fixed scroll 1 is supported by the casing 6 so as to be able to float via a support spring 32 arranged on the outer periphery of the end plate 11, and the rear surface of the end plate 11 of the fixed scroll 1 is concentric with its center as its center. Cylindrical flanges 15 and 16 of the above are protruded upward, and a cylindrical flange 39 protruded downward on the lower surface of the discharge cover 31 between them is sealed via a pair of inner and outer seal members 37. A back pressure chamber 40 surrounded by these members is formed by fitting in a close slidable manner, and the back pressure chamber 40 is hermetically sealed while the gas is being compressed via pressure guiding holes 41 formed in the end plate 11. It communicates with the space 24. Here, the pressure guiding hole 41 is the wrap 1
It is located at a point in contact with the inner diameter side of 2. A high pressure chamber 42 is formed on the inner peripheral side of the back pressure chamber (also referred to as an intermediate pressure chamber) 40, and a low pressure chamber 43 is formed on the outer peripheral side. The upper end of the rotary shaft 5 has an upper bearing 7 provided in the casing 6.
1, and the lower end is supported by the lower bearing 72. In such a structure, the orbiting scroll 2 is driven by the orbiting drive mechanism including the rotating shaft 5, the eccentric pin 53, the drive bush 54, the boss 23, etc. by driving the electric motor M, and the orbiting scroll 2 rotates by the rotation preventing mechanism 3. While being prevented from rotating by itself, it makes a revolution revolution motion on a circular orbit having a radius of revolution revolution. Then, the gas enters the low pressure chamber 45 through the suction pipe 82,
The air is sucked into the closed space 24 through a route not shown. Then, as the volume of the closed space 24 decreases due to the orbiting motion of the orbiting scroll 2, the gas reaches the central portion while being compressed, and enters the high pressure side 44 through the high pressure chamber 42 from the discharge port 13 and is discharged from here. The pipe 83 and the check valve 84 incorporated therein are pushed open and discharged to the outside. At that time, the fixed scroll 1 is pressed against the orbiting scroll 2 by the gas pressure in the high-pressure chamber 42 and the back-pressure chamber 40, and gas leakage from the sealed space 24 is suppressed. When the liquid is sucked into the closed space 24, the fixed scroll 1 floats up and escapes the liquid, thereby preventing the scroll type compression mechanism from being damaged. Although the high pressure chamber 42, the back pressure chamber 40, and the low pressure chamber 43 are formed on the back surface side of the fixed scroll 1 in the above drawing, these are formed on the back surface of the orbiting scroll 2 and the respective chambers 42, 40,43
It is also possible to press the orbiting scroll 2 against the fixed scroll 1 by a back pressure load based on.

[0003]

In the scroll type compressor of this type, the fixed scroll 1 is orbited by the back pressure load based on each area of the high pressure chamber 42, the intermediate pressure chamber 40 and the low pressure chamber 43 and the gas pressure thereof. It is pressed against 2 to prevent gas from leaking from the closed space 24. Here, it is desirable that the back pressure load be substantially equal to the in-cylinder load that pushes the fixed scroll 1 upward based on each area of the closed space 24 and the gas pressure thereof. By the way, the suction side pressure (pressure of the low pressure chamber 43) and the discharge side pressure (pressure of the high pressure chamber 42) of the compressor are variously changed depending on the operating conditions of the refrigerating apparatus in which this type of compressor is incorporated. It is important to apply an appropriate back pressure load to the fixed scroll 1 under all operating conditions. On the other hand, the relationship between the pressure in the intermediate pressure chamber 40 and the pressure in the low pressure chamber 43 has been clarified, and the areas of the intermediate pressure chamber 40 and the low pressure chamber 43 are set based on this relationship. However, how to set the area of the high pressure chamber 42 has not been clarified yet. For this reason, in particular, the back pressure load applied to the fixed scroll 1 becomes excessively large, which may cause damage to the fixed scroll and the orbiting scroll, or increase the required power of the compressor.

The present invention has been proposed in view of the above circumstances, and by appropriately setting the area of the high pressure chamber,
An object of the present invention is to provide a scroll type fluid machine having a long life which prevents damage to a compression mechanism.

[0005]

To this end, the present invention forms a closed space by meshing a fixed scroll and an orbiting scroll having spiral wraps standing on the inner surface of each end plate with each other to form a closed space. A high pressure chamber, an intermediate pressure chamber, or a low pressure chamber is sequentially formed from the center of the fixed scroll or the orbiting scroll toward the outside, and the fixed scroll or the orbiting scroll is formed in the high pressure chamber, the intermediate pressure chamber, or the low pressure chamber. In a scroll-type fluid machine configured to be pressed toward the orbiting scroll or the fixed scroll by the fluid pressure introduced in, the area of the high-pressure chamber, the innermost part formed on the most center side of the fixed scroll and the orbiting scroll. 2 between the closed chambers
Immediately after the two communicate with each other, the laps are set to have an area equal to or smaller than the area of a circle whose diameter is the distance between the two contact points at which the laps abut on each other.

[0006]

According to this structure, the area of the high-pressure chamber is equal to or larger than the average value of the area of the closed space which is in the discharge pressure state when the orbiting scroll makes one revolution by the revolution orbiting motion. Is also set smaller. Therefore, the load applied from the back surface of the fixed scroll or the orbiting scroll by the high pressure chamber becomes equal to or smaller than the load applied from the inner surface of the fixed scroll or the orbiting scroll by the closed space in the discharge pressure state, and the compressor The operating conditions of the refrigerating apparatus in which the is incorporated will vary variously, and an excessive back pressure load will not be applied to the fixed scroll or the orbiting scroll.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, one embodiment of the present invention is shown in FIG.
Its longitudinal sectional view is substantially the same as FIG. The area of the high pressure chamber 42 in the present invention is set as follows. That is, the wrap 12 of the fixed scroll 1 and the wrap 22 of the orbiting scroll 2 are meshed with each other to form a number of closed spaces 24 in point symmetry, and the closed space 24 has a volume equal to that of the wrap 22 of the orbiting scroll 2. It changes with the movement of the position where the first lap 12 contacts. And
Immediately after the two innermost sealed spaces 24A, 24B formed on the innermost sides of the fixed scroll 1 and the orbiting scroll 22 pass each other (that is, the base ends P of the wraps 12, 22).
Immediately after the contact between the wraps 12 and 22), the two points at which the laps 12 and 22 come into contact with each other at the innermost circumference are A,
Assuming B, the area of the high pressure chamber is equal to or smaller than the area of a circle whose diameter is the distance between the points A and B, or is smaller than the area of this circle and the opening area of the discharge port 13 is set as its lower limit. . Here, the area of the circle whose diameter is the distance between the points A and B is such that the closed space 24 is in the discharge pressure state when the orbiting scroll 2 makes one revolution by the orbiting orbiting motion.
The average value of the area of (the pressure of the compressed gas in the closed space 24 is sufficient to be discharged through the discharge port 13) is shown. Therefore, the load that pushes the fixed scroll 1 downward by the high-pressure chamber 42 becomes equal to or smaller than the load that pushes the fixed scroll 1 upward by the closed space 24 in the discharge pressure state, and this compressor is incorporated. Even if the operating conditions of the refrigeration system are changed, the fixed scroll 1 is not subjected to an excessive back pressure load.

[0008]

According to such a structure, the load applied from the back surface of the fixed scroll or the orbiting scroll by the high pressure chamber is the same as the load applied from the inner surface of the fixed scroll or the orbiting scroll by the closed space in the discharge pressure state. Even if it becomes smaller or smaller than that, and the operating conditions of the refrigeration system in which this compressor is incorporated are variously changed, an excessive back pressure load is not applied to the fixed scroll or the orbiting scroll. In addition, damage to the orbiting scroll can be prevented, and increase in required power of the compressor can be suppressed.

In short, according to the present invention, the fixed scroll and the orbiting scroll, in which spiral wraps are erected on the inner surface of each end plate, are meshed with each other to form a closed space. A high pressure chamber, an intermediate pressure chamber, or a low pressure chamber is sequentially formed from the center to the outside on the back side of the fluid, and the fixed scroll or the orbiting scroll is introduced into the high pressure chamber, the intermediate pressure chamber, or the low pressure chamber. In a scroll type fluid machine configured to be pressed against the orbiting scroll or the fixed scroll by pressure, the area of the high pressure chamber is defined between the innermost closed chamber formed on the most center side of the fixed scroll and the orbiting scroll. Immediately after the two have communicated with each other, the two contact points where the laps abut on their innermost circumference The distance it was set to less than the area of a circle the diameter of, from getting a scroll fluid machine of life to prevent damage to the compression mechanism, the present invention is extremely useful industrially.

[Brief description of drawings]

FIG. 1 is a horizontal cross-sectional view showing a scroll unit according to an embodiment of the present invention.

FIG. 2 is an overall vertical sectional view showing a known scroll compressor.

[Explanation of symbols]

 1 Fixed Scroll 2 Orbiting Scroll 11 End Plate 12 Wrap 21 End Plate 22 Wrap 24 Sealed Space 24A Sealed Space 24B Sealed Space 40 Intermediate Pressure Chamber 42 High Pressure Chamber 44 Low Pressure Chamber

Claims (1)

Claim: What is claimed is: 1. A fixed scroll or swivel scroll having spiral wraps standing upright on the inner surface of each end plate meshes with each other to form a closed space. A high pressure chamber, an intermediate pressure chamber, or a low pressure chamber was sequentially formed from the center to the outside on the back side of the scroll, and the fixed scroll or the orbiting scroll was introduced into the high pressure chamber, the intermediate pressure chamber, or the low pressure chamber. In a scroll type fluid machine configured to be pressed toward the orbiting scroll or the fixed scroll by a fluid pressure, the area of the high pressure chamber is defined between the fixed scroll and the orbiting scroll, which is the innermost closed chamber between the innermost closed chambers. Immediately after the two of the above have communicated with each other, between the two contact points where the above laps abut on the innermost circumference Scroll fluid machine, characterized in that set below the area of a circle the release diameter.