JP2001132666A - Displacement compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve performance, to reduce vibration and noise by restraining a backflow to an operating chamber side from a delivery chamber side at insufficient compression time while maintaining high performance at proper compression time with inexpensive constitution in a displacement compressor. SOLUTION: In this displacement compressor having an operating chamber 31 for volumetrically reducing/compressing a sucked hydraulic fluid, a delivery chamber 16 for delivering the hydraulic fluid compressed by the operating chamber 31 and a delivery passage 2f for communicating both 31, 16, the delivery passage 2f has passage resistance turning to the operating chamber 31 from the delivery chamber 16 as compared with passage resistance turning to the delivery chamber 16 from the operating chamber 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive displacement compressor, and more particularly, to a scroll compressor in which backflow from a discharge chamber to a working chamber occurs during insufficient compression.

[0002]

2. Description of the Related Art A conventional general positive displacement compressor is a fluid machine that compresses a working fluid sucked into a working chamber to a required discharge pressure by reducing the working chamber volume. The ratio of the discharge pressure to the suction pressure during operation of the positive displacement compressor is called an operation pressure ratio, and the pressure ratio required when designing the compressor is called a design pressure ratio. The discharge port of the positive displacement compressor is designed to open so that the working chamber communicates with the discharge chamber when the design pressure ratio is reached, and the working fluid in the working chamber is designed to be discharged (prior art 1).

The performance of the displacement type compressor of the prior art 1 during operation differs depending on the relationship between the operating pressure ratio and the design pressure ratio.
In the case of a pressure condition in which the operating pressure ratio and the design pressure ratio are substantially equal, it is called proper compression, and the pressure in the working chamber immediately before opening to the discharge port is increased to substantially the same pressure as the discharge chamber pressure. In the case of this proper compression, immediately after the working chamber communicates with the discharge chamber, the working fluid in the working chamber is gradually discharged to the discharge chamber as the working chamber volume changes. When the operating pressure ratio is higher than the design pressure ratio, it is called insufficient compression, and the pressure in the working chamber immediately before opening to the discharge port is lower than the pressure in the discharge chamber. In the case of this insufficient compression, immediately after the working chamber communicates with the discharge chamber, the working fluid flows backward from the discharge chamber to the working chamber due to a pressure difference between the low-pressure working chamber and the high-pressure discharge chamber, and the working chamber pressure rapidly increases. Get higher. The working fluid in the working chamber that has rapidly increased in pressure leaks from the gap in the sliding portion to the working chamber on the low-pressure side, and the compression power increases.

As one means for reducing the performance degradation at the time of insufficient compression, for example, as disclosed in Japanese Patent Application Laid-Open No. Hei 5-133352, a device provided with a discharge valve on the discharge chamber side of a discharge port is known. is there. According to this, when the pressure in the discharge chamber is higher than the pressure in the working chamber immediately before the opening of the discharge port, the discharge valve is not opened even when the working chamber opens to the discharge port during the insufficient compression, and the working fluid is further compressed and discharged. The working fluid can be discharged into the discharge chamber by opening the discharge valve after reaching the room pressure (prior art 2).

[0005]

However, since the positive displacement compressor of the prior art 2 has a discharge valve having a movable part,
In addition to problems such as maintenance of reliability of the discharge valve, limitation of life, increase in cost, and the like, the discharge valve increases the flow path resistance, so that there is a problem that the performance is reduced during proper compression.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the performance by suppressing the backflow from the discharge chamber side to the working chamber side at the time of insufficient compression while maintaining the high performance at the time of proper compression with an inexpensive structure. Another object of the present invention is to obtain a positive displacement compressor capable of reducing vibration and noise.

[0007]

A first feature of the present invention to achieve the above object is to provide a working chamber for reducing the volume of a sucked working fluid and compressing the working fluid, and a working fluid compressed in the working chamber. A discharge chamber for discharging, and a discharge flow path that communicates the working chamber and the discharge chamber, wherein the discharge flow path is smaller than the flow path resistance from the working chamber to the discharge chamber. This is because the flow path resistance toward the working chamber is configured to be large.

A second feature of the present invention is that the working chamber compresses the sucked working fluid by reducing its volume, a discharge chamber discharging the working fluid compressed in the working chamber, the working chamber and the discharge chamber. And a discharge flow path communicating with the discharge path, wherein the discharge flow path is
The present invention is configured to have a flow passage on the side of the working chamber having a small flow cross section and a flow passage on the side of the discharge chamber having a large flow cross section.

A third feature of the present invention is that a working chamber for reducing the volume of the sucked working fluid and compressing the working fluid, a discharge chamber for discharging the working fluid compressed in the working chamber, the working chamber and the discharge chamber. And a discharge flow path communicating with the discharge path, wherein the discharge flow path is
A flow path on the side of the working chamber having a small flow cross-sectional area, and a flow path on the side of the discharge chamber having a large flow cross-sectional area; and a flow connecting the flow path on the working chamber side and the flow path on the discharge chamber side. The road wall is configured to extend outward and toward the working chamber.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. Note that in the second and subsequent embodiments, some of the components common to the first embodiment will be partially omitted, and redundant description will be omitted. The same reference numerals in the drawings of the respective embodiments indicate the same or corresponding components.

First, a positive displacement compressor according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a first embodiment of the invention.
FIG. 2 is a longitudinal sectional view showing a positive displacement compressor of an embodiment, FIG. 2 is an enlarged cross-sectional view of a discharge flow path in the positive displacement compressor of FIG.
FIG. 5 is a cross-sectional view for explaining a series of compression operations of a fixed scroll and an orbiting scroll in the positive displacement compressor of FIG. In the first embodiment, the present invention is applied to a scroll compressor as a positive displacement compressor.

The overall structure of the scroll compressor 20 in the first embodiment will be described with reference to FIG.

The scroll compressor 20 has a structure in which a compression mechanism 30 and a motor 40 are housed in a closed container 1.

The compression mechanism 30 includes the fixed scroll 2, the orbiting scroll 3, the frame 7, and the Oldham ring 9. The fixed scroll 2 has a wrap 2a formed in a spiral shape and stands upright from a head plate 2b, has a lap tooth bottom 2c and a lap tooth tip 2d, and is fixed to a frame 7. Note that the frame 7 is fixed to the closed container 1.
A discharge port 2e is provided at the center of the fixed scroll 2.
And a discharge channel 2f connected thereto. Details of the discharge port 2e and the discharge channel 2f will be described later.

The orbiting scroll 3 has a wrapped bottom 3c and a wrapped tip 3d with a spiral wrap 3a standing on a head plate 3b. In the fixed scroll 2 and the orbiting scroll 3, the respective wraps 2a and 3a are meshed with each other to form the working chamber 31. The series of changes in the working chamber 31 will be described later in detail.

The motor section 40 includes a stator 11 and a rotor 1
2 and a crankshaft 13. Stator 1
1 is fixed to the closed casing 1, and the rotor 12 is rotatably provided in the stator 12. The crankshaft 13 is fixed to the center of the rotor 13, the upper part of which is supported by a main bearing 18 a provided on the frame 7, and the eccentric upper end of the crankshaft 13 drives the orbiting scroll 3 to orbit via the orbiting bearing 18 b. It is connected as follows.
An oil supply pipe 14 is attached to a lower end of the crankshaft 13. The lower end of the oil supply pipe 14 extends to the lower portion 10 of the sealed container that stores the lubricating oil. An oil supply hole 13a is formed at the center of the crankshaft 13 so as to communicate with the oil supply pipe 14. Through this oil supply hole 13a, lubricating oil is supplied between the main bearing 18a, the orbiting bearing 18b, and the fixed scroll 2 and the orbiting scroll 3. It is supplied to sliding parts and the like.

The suction pipe 5 is connected to an external refrigeration cycle, penetrates the closed vessel 1 to reach the fixed scroll 2, and is provided in communication with the suction port 15. The discharge pipe 6 communicates with the discharge chamber 16, penetrates through the closed container 1, and is connected to an external refrigeration cycle.

Next, details of the discharge port 2e and the discharge channel 2f provided in the fixed scroll 2 in the first embodiment will be described with reference to FIG.

The discharge passage 2f is connected to a first discharge passage 2f1 and a second discharge passage 2f through a discharge port 2e opened to the working chamber 31.
f2 are formed in this order. The first discharge flow path 2f1 is provided with a flow path wall surface W1 extending from the discharge port 2e to the discharge chamber 16 direction.
, Its diameter is D1, and its distance is L
It is one. The second discharge flow channel 2f2 is formed by a flow channel wall surface W2 including a radial wall surface W21 extending from the flow channel wall surface W1 and a flow direction wall surface W22 extending therefrom. The radial wall surface W21 extends outward from the flow path wall surface W1 and toward the working chamber, has an outer diameter of D2, and has a distance L21 extending toward the working chamber. The flow direction wall surface 22 extends from the outer peripheral end of the radial wall surface W21 to the discharge chamber 16 side,
Its diameter is D2 and its distance is L22. In this case, D1 <D2.

As described above, since the discharge passage 2f has the second discharge passage 2f2 which is larger than the first discharge passage 2f1, the discharge passage 16 has a larger resistance than the flow passage resistance from the working chamber 31 to the discharge chamber 16. Thus, a discharge flow path having a large flow path resistance toward the working chamber 31 is formed.

The flow path wall W1 of the first discharge flow path 2f1
The flow direction wall surface W2 of the second discharge passage 2f2 is formed with constant diameters D1 and D2, but may have a gradually changing diameter. In addition, fixed scroll 2
Although the discharge flow path 2f is provided in the orbiting scroll 3, the present invention can be applied.

Next, the compression operation by the fixed scroll 2 and the orbiting scroll 3 in the first embodiment will be described with reference to FIG.

When the motor 12 is energized to rotate the rotor 12, the crankshaft 13 rotates and the orbiting scroll 3 orbits. Accordingly, the working fluid is sucked into the suction port 15 from the suction pipe 5 and is sucked into the working chamber 31 which is a closed space formed by the fixed scroll 2 and the orbiting scroll 3. When the suction stroke is completed, the working chamber 31 is sealed as shown in FIG. 3A, and has a working chamber 31 a formed inside the orbiting scroll 3 and a working chamber 31 a formed outside the orbiting scroll 3. The working chamber 31b is formed on the left and right. Further, as the orbiting scroll 3 orbits, the working chambers 31 formed on the left and right are formed as shown in FIGS.
Since the volumes of a and 31b decrease, the sucked working fluid is compressed while being sent toward the center of the fixed scroll 2. As the orbiting motion of the orbiting scroll 3 further advances, the state of the discharge start shown in FIG. 3D is reached, and the working chambers 31a and 31b communicate with the discharge port 2e to start the discharge stroke. After completing this discharge stroke, FIG.
The state shown in (A) is completed, and the compression operation is started.

In such a compression operation, between the fixed scroll wrap 2a and the revolving scroll wrap 3a, between the fixed scroll tooth tip 2d and the revolving scroll tooth bottom 3c, and further between the fixed scroll tooth bottom 2c and the revolving scroll tooth tip 3d. There is a slight gap, and lubricating oil is constantly supplied for the purpose of sealing the gap and lubricating the sliding portion. That is, the lubricating oil stored in the lower portion 10 of the closed container is passed through the oil supply pipe 14 fixed to the crankshaft 13 and the oil supply hole 13a provided inside the crankshaft 13 to the gaps between the bearings 18a, 18b and the sliding portion. Supplying. However, the working fluid leaks from the working chamber on the high-pressure side to the working chamber on the low-pressure side through the gap that is not sufficiently sealed, and the input power is required by that much, so the performance is reduced. It is necessary to reduce the amount of leakage of the working fluid as much as possible.

As shown in FIG. 3 (D), when the working chambers 31a and 31b whose volumes have been reduced communicate with the discharge port 2e of the fixed scroll 2, the pressure of the working fluid in the working chamber 31 increases. If the pressure is higher than the pressure, the pressure is discharged to the discharge chamber 16 via the discharge flow path 2f. Here, the pressure in the working chamber 31 immediately before opening to the discharge port 2e and the discharge chamber 16
The state of the flow inside the discharge passage 2f that connects the working chamber 31 and the discharge chamber 16 differs depending on the relationship of the internal pressure. When the pressure in the working chamber 31 immediately before opening to the discharge port 2 e and the pressure in the discharge chamber 16 are approximately equal and appropriate compression is performed, the working fluid flows along with the change in the volume of the working chamber 31 to decrease. Is discharged slowly.

In the case of insufficient compression, in which the pressure in the working chamber 31 immediately before the opening of the discharge port 2e is lower than the pressure in the discharge chamber 16, immediately after the working chamber 31 communicates with the discharge port 2e, the discharge chamber 16 Due to the pressure difference between the inside of the working chamber 31 and the working chamber 31,
Backflow occurs. However, from the working chamber 31 to the discharge chamber 1
6 from the discharge chamber 16 to the working chamber 31
Since the discharge flow path 2f has a large flow path resistance toward the working chamber 31, backflow into the working chamber 31 can be suppressed.

As described above, in the embodiment of the present invention,
Since a sudden rise in the pressure in the working chamber 31 immediately after the opening of the discharge port 2e can be mitigated, internal leakage from the high-pressure working chamber 31 at the center to the low-pressure working chamber 31 at the periphery can be reduced, and the performance is improved. In addition, the fluctuation of the gas pressure in the working chamber 31 is reduced, so that low vibration and low noise can be achieved. Moreover, since a discharge valve is not required unlike the related art, the high performance at the time of proper compression is improved. While maintaining the performance, the performance can be improved at the time of insufficient compression, and since a discharge valve serving as a movable portion is not required, reliability can be improved and cost can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view of a discharge channel section according to a second embodiment of the present invention.

In the second embodiment, the distance L1 'of the wall surface W1 of the first discharge channel 2f1 is reduced and the flow of the second discharge channel 2f2 is smaller than that of the first embodiment. Road wall W2
Is different in that the distance L22 'is longer. By doing so, it is possible to configure the discharge flow path 2f in which the flow resistance from the discharge chamber 16 to the working chamber 31 is larger than the flow resistance from the working chamber 31 to the discharge chamber 16.

Next, a third embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 5 is a plan view of a flow path member used in the third embodiment of the present invention, and FIG. 6 is a sectional view taken along line AA of FIG.

In the third embodiment, a flow path member 50 such as a bush is added to an end face of a discharge passage of a fixed scroll 2 of a generally used scroll compressor. The flow path member 50 has the same discharge flow path 2f as the discharge flow path 2f of the first embodiment. According to the third embodiment, the same effect as that of the first embodiment can be obtained without largely changing the design of the fixed scroll of the general scroll compressor.

Next, the fourth, fifth, sixth and seventh embodiments of the present invention will be described.
An embodiment will be described with reference to FIGS.

In the fourth embodiment, as shown in FIG.
Compared to the first embodiment, the third discharge channel 2f3 is added to the second discharge channel 2f2. Third discharge channel 2
f2 is a flow path wall W composed of a radial wall W31 extending from the flow path wall W2 and a flow direction wall W32 extending therefrom.
3. The radial wall surface W31 extends outward from the flow path wall surface W2 toward the working chamber, has an outer diameter D3, and has a distance L31 extending toward the working chamber.
The flow direction wall surface 32 extends from the outer peripheral end of the radial wall surface W31 to the discharge chamber 16 side, has a diameter D3, and has a distance L32. In this case, D2 <D3. By doing so, it is possible to configure the discharge flow path 2f in which the flow resistance from the discharge chamber 16 to the working chamber 31 is larger than the flow resistance from the working chamber 31 to the discharge chamber 16.

In the fifth embodiment, as shown in FIG.
The second embodiment differs from the first embodiment in that the second discharge passage 2f2 is formed eccentrically with respect to the first discharge passage 2f1. More specifically, the fifth embodiment has a flow path structure in which two types of discharge flow paths 2f1 and 2f2 having different inner diameters are arranged so as to have different center axes.

In the sixth embodiment, as shown in FIG.
Compared with the fifth embodiment, the third embodiment is different from the fifth embodiment in that a third discharge passage 2f3 which is further eccentric is formed in the second discharge passage 2f2. The third discharge passage 2f3 is connected to the first discharge passage 2f.
It is eccentric in the same direction as the eccentric direction of the second discharge passage 2f2 with respect to f1.

In the seventh embodiment, as shown in FIG. 10, the third discharge passage 2f3 is different from that of the sixth embodiment.
Is formed eccentrically in a direction opposite to the eccentric direction of the second discharge passage 2f2.

[0037]

According to the present invention, it is possible to improve the performance by suppressing the backflow from the discharge chamber side to the working chamber side at the time of insufficient compression while maintaining the high performance at the time of proper compression with an inexpensive structure. A positive displacement compressor capable of reducing vibration and noise can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a positive displacement compressor according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a discharge channel in the positive displacement compressor of FIG.

FIG. 3 is a cross-sectional view illustrating a series of compression operations of a fixed scroll and an orbiting scroll in the positive displacement compressor of FIG.

FIG. 4 is a sectional view of a discharge channel section according to a second embodiment of the present invention.

FIG. 5 is a plan view of a flow path member used in a third embodiment of the present invention.

6 is a sectional view taken along line AA of FIG.

FIG. 7 is a cross-sectional view of a discharge channel section according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view of a discharge channel section according to a fifth embodiment of the present invention.

FIG. 9 is a cross-sectional view of a discharge channel section according to a sixth embodiment of the present invention.

FIG. 10 is a sectional view of a discharge channel section according to a seventh embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Closed container, 2 ... Fixed scroll, 2a ... Wrap, 2
b ... end plate, 2c ... tooth bottom, 2d ... tooth tip, 2e ... discharge port, 2f ... discharge flow path, 2f1 ... first discharge flow path, 2f2 ...
2nd discharge flow path, 2f3 ... third discharge flow path, 3 ... orbiting scroll, 3a ... wrap, 3b ... head plate, 3c ... tooth bottom, 3d ...
Tooth tip, 5 ... suction pipe, 6 ... discharge pipe, 7 ... frame, 9 ... Oldham ring, 10 ... lower part of sealed container, 11 ...
Stator, 12 ... rotor, 13 ... crankshaft, 1
3a: oil supply hole, 14: oil supply pipe, 15: suction chamber, 16
... Discharge chamber, 18a ... Main bearing, 18b ... Slewing bearing, 2
0: compressor, 30: compression mechanism, 40: electric motor.

Continued on the front page (72) Inventor Go Tsuchiya 502 Kandachi-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratories, Hitachi, Ltd. F-term (reference) 3H029 AA02 AA14 AA21 AB03 BB21 BB47 CC02 CC06 CC25 3H039 AA03 AA12 BB02 BB25 CC01 CC29

Claims (3)

[Claims] A working chamber for compressing the sucked working fluid by reducing its volume, a discharge chamber for discharging the working fluid compressed by the working chamber, and a discharge passage communicating the working chamber and the discharge chamber. Wherein the discharge flow path has a larger flow path resistance from the discharge chamber to the working chamber than a flow resistance from the working chamber to the discharge chamber. . 2. A working chamber for reducing the volume of the sucked working fluid and compressing the working fluid, a discharge chamber for discharging the working fluid compressed by the working chamber, and a discharge passage communicating the working chamber and the discharge chamber. Wherein the discharge passage has a flow passage on the side of the working chamber having a small flow cross-sectional area and a flow passage on the side of the discharge chamber having a large flow cross-sectional area. . 3. A working chamber for compressing the sucked working fluid by reducing its volume, a discharge chamber for discharging the working fluid compressed by the working chamber, and a discharge passage communicating the working chamber and the discharge chamber. The discharge flow path has a flow passage on the side of the working chamber having a small flow cross-sectional area, and a flow passage on the side of the discharge chamber having a large flow cross-sectional area. A positive displacement compressor characterized in that a flow path wall connecting a flow path on the chamber side extends outward and toward the working chamber.