JPH02199288A - Fluid compressor - Google Patents

Abstract

PURPOSE:To reduce incurring of a friction loss between a blade and a cylinder and to improve compression efficiency by providing a bleeding passage through which fluid in the middle of compression is guided in a spiral groove through the bottom of the given portion of the groove and which applies a back pressure of an intermediate pressure value on a blade. CONSTITUTION:Approximately at the intermediate portion, on the suction end side and the delivery end side of a cylinder 7, of an actuating chamber 15, refrigerant gas in the middle of compression and present in the actuating chamber 15 is bled in a bleed passage 30. Refrigerant gas guided in the bleed passage 30 is guided in a spiral groove 13 through the bottom of the given portion of the groove 13, and a back pressure of an intermediate pressure value is applied on a blade 14. This constitution enables reduction of incurring of a friction loss between the blade and the cylinder and improvement of compression efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a fluid compressor for compressing refrigerant gas in a refrigeration cycle, for example, and particularly relates to an improvement in means for applying back pressure to the blades of the fluid compressor. .

(Prior Art) Various types of compressors have been known, such as a reciprocating type and a rotary type. but.

In these compressors, the structure of the driving part such as a crankshaft that transmits one rotational force to the compressor part, and the compression part is complicated and has a large number of parts. moreover.

In order to increase compression efficiency in such compressors.

It is necessary to provide a check valve on the discharge side, but since the pressure difference between both sides of this check valve is very large, gas easily leaks from the check valve, resulting in low compression efficiency. In order to solve these problems, it is necessary to improve the dimensional accuracy and assembly accuracy of each component, which increases manufacturing costs.

A screw pump is also disclosed in US Pat. No. 2,401,189. According to this pump, a rotating body having a cylindrical shape and having a spiral groove formed on its outer peripheral surface is disposed within the sleeve.

A spiral blade is slidably fitted into the groove. By driving the two rotating bodies to rotate, the fluid trapped between two adjacent windings of the blade between the outer circumferential surface of the first rotating body and the inner circumferential surface of the sleeve is transferred from one end of the sleeve to the other end. do. In other words, the screw pump described above only transfers fluid from one end to the other, and does not have the function of compressing fluid.

Therefore, recently, a fluid compressor has been proposed that eliminates the above-mentioned problems, has a relatively simple structure, improves sealing performance, can perform efficient compression, and is easy to manufacture and assemble from nine parts. This is, for example, as shown in FIG. 5, and is used, for example, as a hermetic compressor for refrigerant gas used in a refrigeration cycle.

This compressor main body 1 consists of an electric element 3 and a compression element 4 housed in a sealed case 2. The electric element 3 has an annular stator 5 fixed to the inner surface of the sealed case 2 and an annular rotor 6 provided inside the stator 5. The compression element 4 has a cylinder 7 made of a hollow cylinder, and the rotor 6 is coaxially fitted onto the outer peripheral surface of the cylinder 7. Both ends of the cylinder 7 are rotatably supported by a main bearing 8 and a sub-bearing 9 fixed to the inner surface of the sealed case 2, and both ends of the cylinder 7 are hermetically closed by the main and sub-bearings 8 and 9. ing.

A piston 10 as a cylindrical rotating body is accommodated in the hollow portion of the cylinder 7 along the axial direction. This piston 10 is arranged such that its center axis A is eccentric by a distance Me with respect to the center axis B of the cylinder 7 , and a portion of the outer circumferential surface of the piston 10 is in contact with the inner circumferential surface of the cylinder 7 . Both ends of the piston 10 are rotatably supported by the main and sub bearings 8.9, respectively.

Further, an engagement hole (not shown here) is provided at one end of the piston 7 from the circumferential surface toward the axial direction, and protrudes from the inner circumferential surface of the cylinder 7 into this engagement hole. Here, a drive pin (not shown) is inserted along the radial direction of the cylinder 7 so as to be movable forward and backward.

A spiral groove 13 extending between both ends of the piston 100 is formed on the outer peripheral surface of the piston 10 . The pitch of this spiral groove 13 is from the right side to the left side in the figure of one car.
In other words, it is formed gradually smaller from the suction side to the discharge side of the cylinder 7. A spiral blade 14 is fitted into the groove 13. This blade 14 is made of, for example, a fluororesin material and has appropriate elasticity. The thickness of this blade 14 is the same as that of the spiral groove 1.
3, and each part of the blade 14 can move forward and backward with respect to the groove 13 along the radial direction of the piston 10, and the outer circumferential surface of the blade 14 slides in close contact with the inner circumferential surface of the cylinder 7. It is possible.

The space between the inner circumferential surface of the cylinder 7 and the outer circumferential surface of the piston 10 is formed by the blade 14 into a plurality of working chambers 15.
It is divided into... In other words, each working chamber 15 is formed between two adjacent windings of the blade 14, and extends along the blade 14 from the contact point between the piston 10 and the inner peripheral surface of the cylinder 7 to the next contact point. form. The volume of the working chamber 15 is the cylinder 7.
gradually decreases from the suction side to the discharge side.

A suction hole 16 extending in the axial direction of the cylinder 7 passes through the main bearing 8 located on the suction side of the cylinder 7 . One end of this suction hole 16 opens into the working chamber 15 in the cylinder 7, and the other end opens into the suction tube 1 of the refrigeration cycle.
7 is connected.

Further, the secondary bearing 9 located on the discharge side of the cylinder 7
is provided with a discharge hole 18, one end of which opens into the working chamber 15 inside the cylinder 7, and the other end opens into the sealed case 2. Further, a discharge tube 19 of a refrigeration cycle is connected to the sealed case 2, and communicates with the discharge hole 18.

On the other hand, an oil reservoir 20 in which lubricating oil collects is formed at the inner bottom of the sealed case 2. The lower end opening of the oil suction pipe 21 provided in the main bearing 8 is immersed in the lubricating oil in the oil reservoir 20 . The upper end opening of this oil suction pipe 21 is located on the inner peripheral surface of the main bearing 8 and on the shaft portion 1 of the piston 10.
It opens into a space 8a that does not face 0a. From this.

When the inside of the sealed case 2 is in a high pressure state, the lubricating oil in the oil reservoir 20 flows through the oil suction pipe 21 to the space 8a of the main bearing 8.
It will be sucked up and filled here. Further, an oil guide hole 22 is provided from the end surface of the piston 10 facing the space 8a to a midway point along the axial direction. This end opens at the bottom of the spiral 13 at a predetermined location. Therefore, the lubricating oil sucked up into the space 8a as the piston 10 rotates is introduced into the groove 13 and between the blade 14 and the piston 14 through the oil guide hole 22.

Next, the operation of such a fluid compressor will be explained. When the electric element 3 is energized to rotate the rotor 6, the cylinder 7 rotates together. The rotation of the cylinder 7 is
The power is transmitted to the piston 10 through the pin and the engagement hole, and the piston 10 is driven to rotate with a portion of its outer circumferential surface in contact with the inner circumferential surface of the cylinder 7, and the blade 14 also rotates together. Since this blade 14 rotates with its outer circumferential surface in contact with the inner circumferential surface of the cylinder 7, each part of the blade 14 is rotated as it approaches the contact area between the outer circumferential surface of the three pistons 10 and the inner circumferential surface of the cylinder 7. It is pushed into the groove 13 and moves in the direction of jumping out of the groove 13 as it moves away from the contact portion. On the other hand, when the compression element 4 is actuated, the suction tube 1
Refrigerant gas is sucked into the cylinder 7 through the cylinder 7 and the suction hole 16 .

The sucked refrigerant gas remains trapped in the crescent-shaped working chamber 15 between the windings of the blades 14.

As the piston 10 rotates, the compressed refrigerant gas is sequentially transferred to the working chamber 15 on the discharge side and compressed. It is once discharged to 2 and then returned to the refrigeration cycle through the discharge tube 19.

Further, since the compressed high-pressure gas is once discharged into the sealed case 2 from the discharge hole 19, the pressure inside the sealed case 2 becomes high. Under the influence of this pressure, lubricating oil is sucked up from the oil reservoir 20 into the oil suction pipe 21 and is supplied into the groove 13 through the oil guide hole 22. Therefore, the blade 14 is subjected to back pressure.

Its outer circumferential surface is always in close contact with the inner circumferential surface of the cylinder 7, thereby reliably partitioning the working chambers 15 from each other. Moreover,
The blade 14 smoothly moves forward and backward along the radial direction of the cylinder 7, and its operation is reliable.

According to the fluid compressor that operates in this manner, the refrigerant gas is transported and compressed while being confined within the working chamber 15, so the gas can be compressed efficiently, simplifying the configuration of the compressor and reducing the number of parts. In addition, since the rotor 6 of the electric element 3 is fitted into the cylinder 7 of the compression element 4, there is no need to provide a dedicated four-wheel shaft, bearings, etc. to support the rotor 6, and the configuration of the compressor can be improved. It can be further simplified and the number of parts can be reduced by two.

The cylinder 7 and the piston 10 are in contact with each other while being rotated in the same direction. For this reason, the friction between these members is small and each can rotate smoothly, resulting in less vibration and noise.

A highly efficient compressor can be realized.

(Problems to be Solved by the Invention) However, although the fluid compressor has such various advantages, it also has one problem. That is, the high-pressure gas compressed in the working chamber 15 is discharged into the sealed case 2 from the discharge hole 18. The pressure of this high-pressure gas acts on the lubricating oil in the oil reservoir 20, and the oil suction pipe 21 sucks up the lubricating oil and supplies it to the groove 13. Therefore, the lubricating oil actually supplied into the groove 13 has a pressure substantially equal to the pressure of the high-pressure gas discharged from the discharge hole 18. On the other hand, the blade 14 has a groove 13
There is a narrow gap between them due to the relationship between them going in and out. Therefore, the high-pressure lubricating oil guided into the groove 13 exerts extremely large back pressure on the blade 14 and expands the outer circumferential surface of the blade 14 to bring it into close contact with the inner circumferential surface of the cylinder 7, while expanding the gap between the blade 14 and the groove 13. act. As a result, gas leakage occurs between adjacent working chambers 15, which may reduce compression efficiency, and the lubricating oil itself leaks and back pressure becomes excessive, causing friction loss between the blade 14 and cylinder 7. The occurrence of defects is taken into consideration.

The present invention has been made in view of these circumstances, and its purpose is to apply the optimal back pressure necessary for blade expansion.

It is an object of the present invention to provide a fluid compressor that prevents gas and lubricating oil from leaking between adjacent working chambers, improves compression efficiency, and reduces friction loss between blades and cylinders.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a cylinder pivotally supported within a sealed case, a rotating body pivotally supported within the cylinder, and a spiral shape formed on the outer peripheral surface of the rotating body. In a fluid compressor comprising a groove and a blade fitted into the groove to partition a plurality of working chambers, the fluid being compressed from the working chamber between the suction end side and the discharge end side of the cylinder is compressed into the spiral shape. This fluid compressor is characterized in that a bleed passage is provided for introducing air into the groove through the bottom surface of a predetermined portion of the groove and applying an intermediate back pressure to the blade.

(Function) Fluid in the process of being compressed in the working chamber between the suction end and the discharge end of the cylinder is introduced into the groove from the bottom of a predetermined part of the spiral groove through the bleed passage, and the blade is Since an intermediate back pressure is applied, the back pressure does not become excessive.

(Embodiment) An embodiment of the present invention will be described below based on the drawings.
Since the structure and operation of the fluid compressor are as previously explained with reference to FIG. 5, the same parts are given the same numbers and a new explanation will be omitted here. As shown in FIG. 1, the piston 10 is provided with an air bleed passage 30. This bleed air passage 30 is.

One end thereof opens on the circumferential surface of the piston 10 at an approximately intermediate portion between the suction end side and the discharge end side of the cylinder 7.

The other end opens at a predetermined portion of the bottom surface of the spiral groove 13.

Then, the openings are once drilled in the radial direction toward the central axis of the piston 10.

It consists of holes that are provided along the central axis direction and communicate with each other. Therefore, the compressed fluid in a predetermined portion of the working chamber 15 can be introduced into a predetermined portion of the groove 13 via the bleed passage 30.

As the piston 10 and cylinder 7 rotate, the refrigerant gas introduced into the working chamber 15 is gradually compressed, reaches a predetermined pressure, and is once discharged into the closed case 2 from the discharge hole 18. Further, the fact that the air is guided from the sealed case 2 to a predetermined refrigeration cycle via the discharge tube 19 is exactly the same as that described above.

On the other hand, in the working chamber 15 at a location approximately midway between the suction end and the discharge end of the cylinder 7, the refrigerant gas in the middle of compression in the working chamber 15 is bled into the bleed passage 30. The refrigerant gas guided to the bleed passage 30 is led into the groove 13 from the bottom surface of a predetermined portion of the spiral groove 13, and applies an intermediate back pressure to the blade 14. Unlike the case where the high pressure inside the sealed case 2 is directly applied to the blade 14 as described in FIG. 5, the pressure is lower than this, so it does not become excessive. therefore.

Since the expansion pressure of the blade 14 is at an optimum value and the gap between the blade 14 and the groove 13 is not enlarged more than necessary, there is no gas leak between adjacent working chambers 15.

To explain, as shown in FIG. 2, from the suction end to the discharge end of the cylinder 7, the upper cross-sectional side of the blade 14 is designated by a to f in order, and the lower cross-sectional side is designated by a to f in order. f'' and working chambers 151 between the blades a to f on the upper side of the cross section: A to E,
One end of the air bleed passage 30 opens into the working chamber C, and the other end opens into the groove 13 into which the blade b is fitted. In other words,
Blade b fitted into groove 13 communicating with bleed air passage 30
serves as a partition between one working chamber A and B.

During actual operation, as shown in Figure 4, in each of the working chambers, the pressure rises from the 0 position and is compressed to the highest pressure at the 2π position, and new refrigerant is supplied from the suction end side or the adjacent working chamber. Since fresh gas is introduced, the pressure suddenly drops to the same level as the 0 position. Thereafter, the same action is repeated as one rotation angle becomes a multiple of 2π.

Here, as shown in FIG. 3, in the groove 13 where the bleed passage 30 opens, the back pressure applied to the blade b becomes PC, which is the pressure in the working chamber C. Also.

As the blades 14 are fitted into the grooves 13 so as to be able to move in and out, a narrow gap exists between them, as in the conventional case. Therefore, a portion of the refrigerant gas that is guided into the groove 13 and applies back pressure to the blade b leaks into the working chambers A and B from these gaps. In each of the working chambers A and B, pressure is applied to the refrigerant gas, and P^+
It is the internal pressure of PB. From the groove 13 to each working chamber A,
The amount of gas leaking to B is pc in one working chamber A.
- Differential pressure with PA 1 In working chamber B, P. -PB are determined by the differential pressure. This has a smaller differential pressure than that previously explained in FIG. 5.

Therefore, the amount of gas leakage can be reduced. at the same time.

The expansion pressure of the blade 14 does not become excessive, and the friction loss between the blade 14 and the cylinder 7 is reduced and the blade 1
The fact that wear prevention of 4 can be obtained is as explained above with reference to FIG.

In the above embodiment, the intermediate-pressure refrigerant gas was extracted at position C of the working chamber 15 and applied to position b of the blade 14, but it is not limited to these positions, and the optimal The position may be set appropriately to obtain a suitable intermediate pressure. Therefore, each location is not limited to one location either.

Moreover, such a fluid compressor can be applied not only to refrigeration cycles but also to other compressors.

〔Effect of the invention〕

As explained above, since back pressure is applied to the blade at an intermediate pressure during compression, it is possible to obtain the optimal back pressure necessary for expansion of the blade, and to reduce friction loss between the blade and cylinder. There is no increase in blade wear. Moreover.

The amount of gas leaking from the groove to the working chamber has been reduced.

This has effects such as improving compression efficiency.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the present invention, with Figure 1 being a longitudinal sectional view of a fluid compressor, Figure 2 being a longitudinal sectional view of its main parts, and Figure 3 being a partially enlarged view. Figure 4 is a diagram showing pressure changes with rotation angle in each working chamber.
FIG. 5 is a longitudinal sectional view of a fluid compressor showing a conventional example of the present invention. 2... Sealed case, 7... Cylinder, 10... Rotating body (piston), 13... Groove, 15... Working chamber,
14...Blade, 30...Bleed part. Figure 1 Applicant's representative Patent attorney Takehiko Suzue Figure 2 O π 2π 3π Rotation angle

Claims (1)

[Claims] A cylinder rotatably supported within a sealed case and having a suction end side and a discharge end side, a rotating body that is eccentrically and rotatably supported along the axial direction within this cylinder, and an outer periphery of this rotating body. A spiral groove is provided on the surface at a pitch that gradually decreases from the suction end side to the discharge end side of the cylinder, and the groove is fitted into the groove so as to be freely removable in the approximate radial direction of the rotating body, and the outer peripheral surface is the inner peripheral surface of the cylinder. and a blade that is in close contact with the cylinder and divides the space between the inner circumferential surface of the cylinder and the outer circumferential surface of the rotary body into a plurality of working chambers, and as the cylinder and the rotary body rotate relative to each other. In a fluid compressor that sequentially transfers fluid that flows into a working chamber from the suction end side of the cylinder to the working chamber on the discharge end side of the cylinder, compresses it, and once discharges it into a sealed case, the fluid flows between the suction end side and the discharge end of the cylinder. A bleed passage is provided for introducing fluid in the middle of compression from the working chamber between the sides into the groove through the bottom surface of a predetermined portion of the spiral groove and applying an intermediate back pressure to the blade. fluid compressor.