JP2004190510A - Gas compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas compressor capable of efficiently compressing refrigerating gas directly after starting the compressor, securing a vane back pressure which is suitable in regular running. <P>SOLUTION: A rear back pressure space 28 communicates an oil reservoir 27 with a bottom of a vane groove 15 via an back pressure oil supply passage 29. Midway along the back pressure supply passage 29, there is provided with a back pressure opening and closing valve 30 which opens when the pressure difference is not greater than a predetermined value, and is closed when it exceeds the predetermined value, and there is provided with a thread groove pump 40 for flowing the oil in the back pressure oil supply passage in the compressor rotation. This makes, at starting the compressor, the thread groove pump 40 feed the oil in the reservoir 27 into the bottom of the vane groove 15 via the back pressure oil supply passage 29 and ejects the vane 16 out of the vane groove 15. On ejecting the vane 16, the compressor starts to compress the refrigerant gas, the back pressure opening and closing valve 30 closes when the pressure difference between the oil reservoir 27 and the rear back pressure space 28 exceeds the predetermined value to run steady operation under a suitable vane back pressure. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vane rotary type gas compressor used in a car air-conditioning system and the like, and particularly, performs a refrigerant gas compression operation efficiently immediately after the compressor is started, while securing an appropriate vane back pressure during a steady operation. To a vane rotary type gas compressor.
[0002]
[Prior art]
Conventionally, in this type of vane rotary type gas compressor, the bottom space of the vane, that is, the vane is slidably mounted in order to prevent the tip of the vane from separating from the inner surface of the cylinder during the steady operation. Oil at an appropriate pressure is supplied to the bottom of the vane groove of the rotor as back pressure oil. The appropriate pressure of the back pressure oil is an intermediate pressure between the suction pressure of the refrigerant gas and the discharge pressure of the compressed and discharged refrigerant gas in a section where the vane is in the compression stroke from the suction stroke. Is high pressure corresponding to the discharge pressure of the refrigerant gas. The pressures in these sections are collectively called vane back pressure.
[0003]
Incidentally, the required appropriate value of the vane back pressure differs between the steady operation and the startup of the compressor. If the appropriate value of the back pressure of the vane is set to a low value in accordance with the steady operation, the back pressure of the vane at the time of start-up is insufficient, and the vane popping property is deteriorated. A phenomenon of so-called start-up chattering may occur, in which a phenomenon occurs in which the gasket sinks into the groove and jumps up to collide with the inner peripheral surface of the cylinder.
[0004]
Conventionally, in order to solve the problem of the difference between the vane back pressure required at the time of the steady operation and the start of the compressor, the vane back pressure supplied to the bottom of the vane groove at the time of the start and the steady operation is conventionally known. Is to be changed. (For example, refer to Patent Document 1).
[0005]
However, according to the conventional gas compressor described in Patent Literature 1, although there is no problem during the steady operation, the following problem may occur immediately after the compressor is started.
[0006]
That is, in this conventional gas compressor, it is assumed that the vane back pressure is supplied to the bottom of the vane groove, though slightly, in order for the vane to fly out at the time of startup. Due to the weak vane back pressure, the centrifugal force generated after the rotor starts rotating integrally with the rotor shaft causes the tip of the vane to project even slightly from the outer peripheral surface of the rotor to compress and discharge the refrigerant gas. Unless it is not possible. Therefore, for example, when the compressor is started in a state where all the vanes are buried in the vane grooves of the rotor, such as immediately after the compressor is attached to the air conditioning system of the vehicle, the refrigerant in the compressor is filled with the refrigerant. Since the oil has not yet been dissolved and the viscosity of the oil is high, the centrifugal force acting on the vane cannot easily overcome the resistance of the oil film between the vane and the vane groove. Therefore, it takes time for the tip of the vane to protrude even slightly from the outer peripheral surface of the rotor, and it takes more time to generate the back pressure of the vane, so that the refrigerant gas can be efficiently compressed immediately after the compressor is started. In some cases, the start of cooling may be poor.
[0007]
Also, according to the conventional gas compressor, it takes a lot of time to generate the back pressure of the vane, even after it has been installed in the vehicle air-conditioning system and has been operated repeatedly and repeatedly, just like immediately after installation. In some cases, the compression operation of the refrigerant gas cannot be performed efficiently immediately after the compressor is started, and the start-up of cooling may be poor. In this case, the pressure on the suction side of the compressor becomes higher than the pressure on the discharge side depending on the state of the vehicle being left unattended. For example, the hood of a vehicle is exposed to sunlight but the cabin is left in the shade, and the condenser of the air conditioning system inside the hood is exposed to high temperatures, This is the case when a certain evaporator has a lower temperature than the condenser. In this case, the resistance of the oil film between the vane and the vane groove is small because the refrigerant is dissolved in the oil to some extent compared to immediately after the compressor is installed, but the centrifugal force can easily overcome the pressure applied to the tip of the vane. Instead, it takes time for the tip of the vane to protrude even slightly from the outer peripheral surface of the rotor.
[0008]
[Patent Document 1]
JP 2001-271772 A
[0009]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to ensure a proper vane back pressure at the time of steady operation and efficiently perform a refrigerant gas compression operation immediately after the compressor is started. To provide a gas compressor capable of performing the following.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a cylinder having a side block attached to an end face, a rotor rotatably installed through a rotor shaft inside the cylinder, and an outer peripheral surface of the rotor. A vane mounted in the vane groove, and protruding and retracting from the outer peripheral surface of the rotor toward the inner peripheral surface of the cylinder, and the cylinder, the side block, the rotor and the small chamber inside the cylinder partitioned by the vane, A compression chamber for sucking, compressing and discharging the refrigerant gas by the rotation of the rotor, and an oil reservoir on which the pressure of the refrigerant gas discharged from the compression chamber acts; A rear back pressure space formed by a wall surface including a rear side end surface of the air passage communicates with the rear back pressure space, and the vane starts a compression process from a suction stroke. A high pressure oil that opens at one end into the oil reservoir and at the other end at the bottom of the vane groove after the communication between the bottom of the vane groove and the saray groove is interrupted at the other end; A supply path and an inlet are opened to the oil reservoir, and an outlet is provided in the middle of the back pressure oil supply path communicating with the rear back pressure space side and the back pressure oil supply path. A back pressure on-off valve that opens when the difference from the pressure in the rear back pressure space is equal to or less than a predetermined value and closes when the difference exceeds a predetermined value, And a thread groove pump disposed downstream of the back pressure on-off valve and flowing oil in the back pressure oil supply path by rotation of the rotor shaft.
[0011]
According to the present invention, when the compressor is stopped, there is almost no pressure difference between the oil reservoir and the rear back pressure space. Therefore, the back pressure on-off valve of the back pressure oil supply passage is opened, and the oil reservoir and the oil reservoir are connected via the back pressure oil supply passage. The rear back pressure space communicates. Immediately after the compressor is started, the oil in the oil sump is guided to the rear back pressure space by the pump action of the thread groove pump, and oil is actively supplied from the rear back pressure space to the bottom of the vane groove via the sali groove. You. As a result, the vane jumps out of the vane groove, and normal compression of the refrigerant gas is started. Then, the pressure of the oil sump becomes higher than that of the rear back pressure space, and the back pressure opening / closing valve which has been opened up to that time is closed. In the subsequent steady-state operation of the compressor, the sali-groove and the back pressure oil supply path are not communicated with each other, so that the excess vane back pressure does not act on the vanes, the appropriate intermediate pressure is maintained as the vane back pressure, and the extra power Never need.
[0012]
In the present invention, the thread groove pump can be provided on the inner peripheral side of the rotor shaft. In the case of this structure, regarding the thread groove pump, (1) a cylindrical inner surface provided on the inner periphery of the rotor shaft, and a right-hand screw provided inside the cylindrical inner surface with a predetermined gap from the cylindrical inner surface. Or (2) a left-handed female screw provided on the inner periphery of the rotor shaft, and a predetermined gap between the female screw and the female screw inside the female screw. And a cylindrical surface.
[0013]
In the present invention, the thread groove pump can be provided on the outer peripheral side of the rotor shaft. In the case of this structure, regarding the thread groove pump, (1) a cylindrical surface provided on the outer periphery of the rotor shaft, and a left-hand thread shape provided at a predetermined distance from the cylindrical surface outside the cylindrical surface. Or (2) a right-handed male screw provided on the outer periphery of the rotor shaft, and a cylinder provided outside the male screw at a predetermined distance from the male screw. A configuration including an inner surface can be employed.
[0014]
In the present invention, a cylinder discharge hole for discharging the refrigerant gas compressed in the compression chamber, and a discharge valve for opening and closing the cylinder discharge hole during operation of the compressor, the discharge valve is provided when the compressor is stopped. A configuration in which the cylinder discharge hole is opened can be adopted.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a gas compressor according to the present invention will be described in detail with reference to FIGS.
[0016]
The gas compressor according to the present embodiment shown in FIG. 1 has a compression mechanism 2 housed in a compressor case 1 having an open end, and a front head 3 attached to an open end of the compressor case 1. The structure is adopted.
[0017]
The compression mechanism 2 has a cylinder 4 having a substantially elliptical inner circumference, side blocks 5 and 6 are attached to both end surfaces of the cylinder 4, and a circular section is provided inside the cylinder 4 via a rotor shaft 7. The rotor 8 is installed rotatably.
[0018]
The rotor shaft 7 is provided integrally with the axis of the rotor 8 and is supported via bearings 9 and 10 of the front and rear side blocks 5 and 6. The bearings 9, 10 of the side blocks 5, 6 have a hole shape penetrating the front and back surfaces of the respective side blocks 5, 6.
[0019]
The front end 7F of the rotor shaft 7 projects from the bearing 9 of the front side block 5 through the boss 11 of the front head 3 to the outside. A pulley 13 is rotatably mounted on the outer periphery of the boss portion 11 of the front head 3 via a bearing 12, and an electromagnetic clutch 14 is provided on an end face side of the pulley 13. The pulley 13 and the rotor shaft 7 are connected by the ON operation of the clutch 14, and the rotor shaft 7 rotates integrally with the pulley 13. The pulley 13 is connected to an engine-side pulley via a belt (not shown) or the like, and rotates by the power of the engine.
[0020]
As shown in FIG. 2, five slit-shaped vane grooves 15 are cut into the outer peripheral surface of the rotor 8, and one vane 16 is slidably mounted in each of the vane grooves 15. . The five vanes 16 are provided so as to be able to protrude and retract in the radial direction from the outer peripheral surface of the rotor 8 to the inner peripheral surface of the cylinder 4.
[0021]
The inside of the cylinder 4 is divided into a plurality of small chambers by the inner wall of the cylinder 4, the inner surfaces of the side blocks 5 and 6, the outer peripheral surface of the rotor 8, and both side surfaces on the tip end side of the vane 16. is there. The compression chamber 17 has a structure in which the rotation of the rotor 8 in the direction of the arrow R in the drawing repeatedly changes the volume, and the suction, compression, and discharge of the refrigerant gas is performed by the volume change.
[0022]
That is, when the volume of the compression chamber 17 changes, the low-pressure refrigerant gas in the suction chamber 18 communicates with the suction port 5 a of the front side block 5 and the suction passage 19 of the cylinder 4 when the volume increases. It is sucked into the compression chamber 17 via a suction port (not shown) dug in the end face of the side block 6. Then, when the volume of the compression chamber 17 starts to decrease, the refrigerant gas in the compression chamber 17 starts to be compressed due to the volume reduction effect. Thereafter, when the pressure of the compressed refrigerant gas becomes higher than the pressure on the side of the discharge chamber 23 in the outer space of the cylinder 4, the discharge valve 22 of the cylinder discharge hole 21 located near the short-diameter portion of the cylinder 4 is opened.
[0023]
When the discharge valve 22 is opened as described above, the high-pressure refrigerant gas in the compression chamber 17 flows out of the cylinder discharge hole 21 toward the discharge chamber 23 in the outer space of the cylinder 4. Simultaneously with the passage of the vane 16 through the discharge hole 21, the pressure difference between the next compression chamber 17 and the discharge chamber 23 sandwiching the discharge valve 22 is reversed, and the discharge valve 22 closes.
[0024]
The high-pressure refrigerant gas flowing out to the discharge chamber 23 side is discharged to the discharge chamber 25 through the oil separator 24 attached to the rear side block 6, as shown in FIG. The high-pressure refrigerant gas discharged into the discharge chamber 23 contains oil for lubricating the sliding portion of the compressor body and sealing the gap portion in a mist state. The oil component in the high-pressure refrigerant gas is separated and captured by the separation filter 26 of the oil separator 24, and is dropped and stored in the oil pool 27 at the bottom of the discharge chamber 25.
[0025]
A high pressure of the discharge chamber 25, that is, a pressure Pd of the high-pressure refrigerant gas discharged from the compression chamber 17 into the discharge chamber 25 (hereinafter referred to as discharge pressure) acts on the oil reservoir 27 at the bottom of the discharge chamber 25.
[0026]
A rear back pressure space 28 is provided between the oil separator 24 and the rear side block 6 at the center of the rotating shaft of the compression mechanism 2. A back pressure on-off valve 30 is provided.
[0027]
The rear back pressure space 28 is formed by a wall surface including the oil separator 24, a part of the rear side block 6, and a rear end face (one end face) 7 </ b> R of the rotor shaft 7.
[0028]
The back pressure oil supply passage 29 has a diameter of 2 to 3 mm. The inlet of the back pressure oil supply passage 29 opens to the oil reservoir 27, and the outlet of the back pressure oil supply passage 29 communicates with the rear back pressure space 28. I have.
[0029]
The back pressure on-off valve 30 is installed immediately after the inlet of the back pressure oil supply passage 29, and has an inner cylindrical valve chamber 31-1, an inner conical sealing surface 31-2, and a steel ball 32 functioning as a valve body. And a compression spring 33.
[0030]
The valve chamber 31-1 is provided at the inlet of the back pressure oil supply passage 29, and is formed by enlarging the inner diameter of the back pressure supply passage 29.
[0031]
The seal surface 31-2 is provided continuously to the back of the valve chamber 31-1, and the valve chamber 31-1 side is formed in a large-diameter 90 ° tapered shape.
[0032]
The steel ball 32 has a diameter slightly smaller than the inner diameter of the valve chamber 31-1, is freely movable in the valve chamber 31-1, and is provided so as to be able to be in close contact with the sealing surface 31-2. I have. When the steel ball 32 is in close contact with the sealing surface 31-2, the back pressure on-off valve 30 is closed, and the back pressure oil supply passage 29 is closed. When the steel ball 32 separates from the sealing surface 31-2, the back pressure on-off valve 30 is opened, and the back pressure oil supply passage 29 is opened. The pressure of the oil reservoir 27, that is, the discharge pressure Pd acts on the steel ball 32 from the inlet side of the back pressure oil supply passage 29, and at the same time, the pressure of the rear back pressure space 28 from the bottom side of the sealing surface 31-2. Also works.
[0033]
The compression spring 33 is provided such that one end thereof comes into contact with the steel ball 32 from the bottom of the sealing surface 31-2, and always urges the steel ball 32 in a direction to be separated from the sealing surface 31-2.
[0034]
Even if the pressure of the oil reservoir 27 (discharge pressure Pd) is higher than the pressure of the rear back pressure space 28, if the difference is equal to or less than a predetermined value, the steel force 32 is applied by the spring force of the compression spring 33 to the sealing surface 31-. Pulled away from 2. As a result, the back pressure on-off valve 30 is opened, and the back pressure oil supply passage 29 is set in an open state. When the pressure of the oil reservoir 27 (discharge pressure Pd) is higher than the pressure of the rear back pressure space 28 and the difference exceeds a predetermined value, the steel ball 32 resists the spring force of the compression spring 33 due to the difference pressure. Then, the steel ball 32 moves to the sealing surface 31-2 side, and the steel ball 32 comes into close contact with the sealing surface 31-2. Thereby, the back pressure on-off valve 30 is closed, and the back pressure oil supply passage 29 is set to a closed state.
[0035]
In particular, in the gas compressor of the present embodiment, since the appropriate vane back pressure during steady operation is about 55 to 70% of the discharge pressure Pd, the pressure of the oil sump 27 (discharge pressure Pd) is reduced to the rear back pressure space 28. Is higher than the pressure of 0.3 to 0.5 MPa or more, the spring force of the compression spring 33 is set so that the steel ball 32 comes into close contact with the sealing surface 31-2 to close the back pressure oil supply passage 29. ing. This spring force setting is an example in the case of using R134a as the refrigerant gas, but the spring force setting of the compression spring 33 differs depending on the type of the refrigerant gas used. For example, when R22 or R407C is used as the refrigerant gas, the discharge pressure Pd during steady operation is 30 to 50% higher than when R134a is used. Accordingly, when the pressure of the oil reservoir 27 (discharge pressure Pd) becomes higher than the pressure of the rear back pressure space 28 by 0.5 to 0.9 MPa or more, the steel ball 32 comes into close contact with the sealing surface 31-2 and the back pressure oil is supplied. The spring force of the compression spring 33 is set so that the path 29 is closed.
[0036]
As means for opening and closing the back pressure on-off valve 30 of the present embodiment with a desired pressure difference, not only the setting of the spring force but also the setting between the inner diameter of the valve chamber 31-1 and the outer diameter of the steel ball 32. It is also possible to appropriately select the gap formed by the above. If the gap between the inner diameter of the valve chamber 31-1 and the outer diameter of the steel ball 32 is widened while keeping the spring force constant, the pressure difference required for the opening / closing operation increases, and the back pressure on-off valve 30 becomes difficult to close. When it is narrowed, the pressure difference required for the opening / closing operation becomes small and the door is easily closed.
[0037]
On the cylinder-facing surface of the rear side block 6, a salary groove 34 is formed around the bearing 10. The sali groove 34 (hereinafter, referred to as a rear sali groove) is formed such that the bottom of the vane groove 15 faces and communicates from the side surface during the period from the suction stroke of the refrigerant gas to the compression stroke.
[0038]
Further, the rear side salary groove 34 is configured to communicate with the rear back pressure space 28 via the communication hole 35 of the rear side block 6.
[0039]
Therefore, when the back pressure on-off valve 30 is opened and the back pressure oil supply passage 29 is set to the open state, the oil sump 27 is connected to the oil reservoir 27 via the back pressure oil supply passage 29, the rear back pressure space 28, and the communication hole 35. The rear side salary groove 34 communicates.
[0040]
In the gas compressor according to the present embodiment, a perfect circular rotor 8 is arranged at the center of the inner elliptical cylinder 4 and two crescent-shaped cylinder chambers are formed at positions opposed to each other by 180 °. A series of operations such as suction, compression and discharge of refrigerant gas can be performed in the chamber. From the relationship with this structure, two rear side salary grooves 34 are provided, one each at a position facing 180 ° with the rotor shaft 7 interposed therebetween. Similarly, as shown in FIG. 2, two of the aforementioned suction passages 19, suction ports 20, cylinder discharge holes 21, discharge valves 22, discharge chambers 23, etc. are also provided.
[0041]
Further, in the gas compressor of the present embodiment, since five vanes 16 are arranged on the rotor 8, the compression chamber divided into vanes in one crescent-shaped cylinder chamber during one rotation of the rotor 8 has five vanes. Formed once. Therefore, during one rotation of the rotor 8, a series of operations of sucking, compressing, and discharging refrigerant gas is performed five times in one crescent cylinder chamber, and is performed ten times in both cylinder chambers. Since the number of vanes of five is an odd number, the operations of suction, compression, and discharge in both cylinder chambers are alternately performed in opposite phases.
[0042]
The rear saliary groove 34 and the oil sump 27 communicate with the oil supply hole 36 of the rear side block 6 via the clearance of the bearing 10. In this communication route, the oil in the oil sump 27 is decompressed when passing through the clearance of the bearing 10, and the decompressed oil is supplied to the rear-side salary groove 34. The pressure of the reduced pressure oil is an intermediate pressure between the suction pressure and the discharge pressure of the refrigerant gas.
[0043]
A sali groove 37 is also formed on the cylinder facing surface of the front side block 5. The front sali-groove 37 is formed so that the bottom of the vane groove 15 faces and communicates with the side surface at the time of the refrigerant gas suction stroke to the compression stroke, similarly to the rear sali groove 34.
[0044]
The front side sali-groove 37 is formed in the oil sump 27 through the clearance of the bearing 9 of the front side block 5 and the oil supply holes 36, 36, 36 of the front side block 5, the cylinder 4 and the rear side block 6. Communicating. Also in this communication route, the oil in the oil sump 27 is depressurized when passing through the clearance of the bearing 9, and the decompressed oil is supplied to the front-side salary groove 37. In addition, two front side salary grooves 37 are formed for the same reason as the rear side salary groove 34. The pressure of the decompressed oil is also an intermediate pressure between the suction pressure and the discharge pressure of the refrigerant gas.
[0045]
The high pressure oil supply passage 38 is provided in the rear side block 6. One end of the high-pressure oil supply passage 38 communicates with the oil supply hole 36 of the rear side block 6 through an annular groove 39 partially hollowing the inner surface of the bearing 10 of the rear side block 6. It is structured to open to the oil reservoir 27 side via the supply hole 36. The other end of the high-pressure oil supply passage 38 has a structure that opens to the bottom of the vane groove 15 after the communication between the bottom of the vane groove 15 and the saray grooves 34 and 37 is cut off.
[0046]
That is, in the gas compressor of the present embodiment, after the communication between the bottom of the vane groove 15 and the sali grooves 34 and 37 is interrupted, the bottom of the vane groove 15 communicates with the other end of the high-pressure oil supply path 38 from the side. The high-pressure oil corresponding to the discharge pressure Pd present in the oil reservoir 27 passes through the oil supply hole 36, the annular groove 39, and the high-pressure oil supply passage 38 of the rear side block 6, and becomes the vane back pressure at the bottom of the vane groove 15. Directly pumped. That is, in the gas compressor of the present embodiment, an intermediate pressure between the discharge pressure and the suction pressure acts as a vane back pressure on the bottom of the vane groove 15 of the vane 16 in the suction / compression stroke in the steady operation state, At the bottom of the vane groove 15 of the vane 16 during the discharge stroke, the discharge pressure acts as a vane back pressure. If the other end of the high pressure oil supply path 38 communicates with the bottom of the vane groove 15 before the communication between the bottom of the vane groove 15 and the sali grooves 34 and 37 is interrupted, the vane of the vane 16 in the suction / compression stroke is The back pressure increases due to the influence of the discharge pressure from the high-pressure oil supply passage 38. For this reason, the load at which the tip end of the vane 16 is pressed against the inner peripheral surface of the ellipse of the cylinder 4 increases, and the sliding resistance increases, the power increases, and the fuel efficiency of the vehicle is adversely affected.
[0047]
The bottom space of the five vane grooves 15 of the rotor 8, the total of four sali grooves 34, 37 provided two in each of the side blocks 5, 6, and the rear back pressure space 28 of the rear side block 6 are on the rear side. The communication hole 35 of the side block 6 forms a structure that communicates with each other as one space. The entire one space communicating with each other is simply referred to as a back pressure space. The total volume of the back pressure space is approximately twice the total value of the bottom space volume of the five vane grooves 15 formed when all the five vanes 16 are in contact with the inner peripheral surface of the ellipse of the cylinder 4. It has become. The reason why the total volume of the back pressure space is set in this manner is to largely reduce transmission of oil at the bottom of the vane groove 15, that is, back pressure oil to the surroundings due to the movement of the vane 16 during the steady operation of the compressor. This is because a proper balance between what the user wants to do and how to reduce the amount of oil in the oil reservoir 27 so as not to be too small is considered.
[0048]
A thread groove pump 40 is provided in the middle of the back pressure oil supply path 29, and the thread groove pump 40 is disposed downstream of the back pressure on-off valve 30. In particular, in this embodiment, the screw groove pump 40 is installed immediately before the outlet of the back pressure oil supply passage 29.
[0049]
The thread groove pump 40 can be provided on the inner peripheral side of the rotor shaft 7, or can be provided on the outer peripheral side of the rotor shaft 7.
[0050]
In the gas compressor of FIG. 1, an example is shown in which a thread groove pump 40 is provided on the inner peripheral side of the rotor shaft 7, and details of the peripheral portion including the thread groove pump 40 in FIG. 1 are shown in FIG. . FIG. 4 is a view showing details of another embodiment in which the thread groove pump 40 is provided on the inner peripheral side of the rotor shaft 7, similarly to FIG. 3.
[0051]
5 shows an example in which a thread groove pump 40 is provided on the outer peripheral side of the rotor shaft 7, and details of a peripheral portion including the thread groove pump 40 in FIG. 5 are shown in FIG. FIG. 7 is a view showing details of another embodiment in which the thread groove pump 40 is provided on the outer peripheral side of the rotor shaft 7, similarly to FIG. 6.
[0052]
<Structure description of thread groove pump 40 shown in FIG. 1 (FIG. 3)>
The thread groove pump 40 shown in the figure has a rear end portion 7R of the rotor shaft 7 formed in a cylindrical shape, and a right-hand screw formed inside the cylinder of the rotor shaft rear cylindrical portion 41 with a predetermined gap from the cylindrical inner surface 42. A male screw 43 having a shape is provided.
[0053]
Here, regarding the structure of the male screw 43, a portion of the oil separator 24 facing the center of the rotor shaft rear end surface 7 </ b> R is formed in a rod-like shape so as to project toward the inside of the cylinder of the rotor shaft rear cylindrical portion 41. At the same time, a structure in which a right-hand thread is formed in the rod-shaped protrusion 44 is employed.
[0054]
In short, the thread groove pump 40 shown in the figure has a cylindrical inner surface provided on the inner circumference of the rotor shaft 7, that is, a cylindrical inner surface 42 of the rotor shaft rear cylindrical portion 41, and the cylindrical inner surface inside the cylindrical inner surface 42 and the predetermined inner surface. This is a structure including a right-handed male screw 43 provided with a gap therebetween, and is of a type in which a cylindrical inner surface 42 of the inner circumference of the rotor shaft 7 rotates.
[0055]
In the gas compressor employing the thread groove pump 40 shown in the figure, the above-mentioned back pressure oil supply passage 29 passes through the center of the rod-shaped protrusion 44 of the oil separator 24 and is located on the tip end side of the rod-shaped protrusion 44. From the inside of the rotor shaft rear cylindrical portion 41, and from there through the space between the male screw 43 of the thread groove pump 40 and the cylindrical inner surface 42 from the cylindrical inlet side of the rotor shaft rear cylindrical portion 41. The structure communicates with the back pressure space 28. Therefore, the gas compressor has a structure in which the vicinity of the cylindrical inlet of the rotor shaft rear cylindrical portion 41 becomes an outlet of the back pressure oil supply passage 29, and the screw groove pump 40 of FIG. .
[0056]
<Description of the structure of the thread groove pump shown in FIG. 4>
The screw groove pump 40 shown in the figure has a rear end 7R of the rotor shaft 7 formed in a cylindrical shape, and a female screw 45 having a left-hand thread shape provided on a cylindrical inner surface 42 of the rotor shaft rear cylindrical portion 41. A cylindrical surface 46 is provided inside a female screw 45 with a predetermined gap from the female screw.
[0057]
Here, as for the cylindrical surface 46 provided with a predetermined gap from the female screw 45 as described above, a portion of the oil separator 24 facing the center of the rotor shaft rear end surface 7R is replaced with a rotor shaft rear cylindrical portion. A structure in which a rod-shaped protrusion is formed toward the inside of the cylinder 41 and the outer periphery of the rod-shaped protrusion 44 is formed in a cylindrical surface shape is adopted.
[0058]
In short, the thread groove pump 40 shown in the figure has a left-handed female screw 45 provided on the inner periphery of the rotor shaft 7 (the cylindrical inner surface 42 of the rotor shaft rear cylindrical portion 41), and the female screw 45 inside the female screw 45. This is a structure comprising a screw and a cylindrical surface 46 (outer peripheral surface of the rod-shaped protrusion 47) provided with a predetermined gap, and a female screw 45 on the inner periphery of the rotor shaft 7 is rotated.
[0059]
In the gas compressor employing the thread groove pump 40 shown in the figure, the above-mentioned back pressure oil supply passage 29 passes through the center of the rod-shaped protrusion 44 of the oil separator 24 and is located on the tip end side of the rod-shaped protrusion 44. From the inside of the rotor shaft rear cylindrical portion 41, and from there through the space between the female screw 45 of the thread groove pump 40 and the cylindrical surface 46 from the cylindrical inlet side of the rotor shaft rear cylindrical portion 41. The structure communicates with the back pressure space 28. Therefore, also in this case, the vicinity of the cylindrical inlet of the rotor shaft rear cylindrical portion 41 becomes the outlet of the back pressure oil supply passage 29, and the screw groove pump 40 of FIG.
[0060]
<Structure description of thread groove pump 40 shown in FIG. 5 (FIG. 6)>
The screw groove pump 40 shown in the figure has a center part of the rotor shaft rear end face 7R protruding in a rod shape toward the oil separator 24 facing the same, and the outer peripheral surface of the rod protruding part 47 is formed in a cylindrical surface shape. A left-handed female screw 45 is provided outside the cylindrical surface 48 with a predetermined gap.
[0061]
Here, regarding the structure of the female screw 45, a hole 49 into which the rod-shaped protrusion 47 is inserted is formed on the oil separator 24 side, and a left-hand thread groove is formed on the inner surface of the hole 49. Adopted.
[0062]
In short, the thread groove pump 40 shown in the figure has a cylindrical surface 48 provided on the outer periphery of the rotor shaft 7 (outer peripheral surface of the rod-shaped projection 47) and a predetermined space outside the cylindrical surface 48 with the cylindrical surface. And a left female screw 45 provided on the outer periphery of the rotor shaft 7, and a cylindrical surface on the outer periphery of the rotor shaft 7 rotates.
[0063]
In the gas compressor employing the thread groove pump 40 shown in the figure, the above-mentioned back pressure oil supply passage 29 enters the hole 49 of the oil separator 24 from the bottom side of the hole 49, and further from the hole 49 The structure passes through the space between the female screw 45 of the pump 40 and the cylindrical surface 48 and communicates with the rear back pressure space 28 from the inlet side of the hole 49. Therefore, in this case, the vicinity of the inlet of the hole 49 is an outlet of the back pressure oil supply passage 29, and the screw groove pump 40 of FIG.
[0064]
<Description of the structure of the thread groove pump shown in FIG. 7>
The thread groove pump 40 shown in the figure has a center portion of the rotor shaft rear end surface 7R protruding in a rod shape toward the oil separator 24 facing the rotor shaft end portion 7R. And a cylindrical inner surface 50 is provided outside the male screw 43 with a predetermined gap from the male screw.
[0065]
Here, regarding the structure of the cylindrical inner surface 50 provided with a predetermined gap from the male screw 43 as described above, a hole 49 into which the rod-shaped protrusion 47 is inserted is formed in the oil separator 24 side, A structure in which the inner surface of the hole 49 is formed in a cylindrical inner surface shape is adopted.
[0066]
In short, the thread groove pump 40 shown in the figure includes a right male screw 43 provided on the outer periphery of the rotor shaft 7 and a cylindrical inner surface 50 provided outside the male screw 43 at a predetermined interval from the male screw. This is a type in which the male screw 43 on the outer periphery of the rotor shaft 7 rotates.
[0067]
In the gas compressor employing the thread groove pump 40 shown in the figure, the above-mentioned back pressure oil supply passage 29 enters the hole 49 of the oil separator 24 from the bottom side of the hole 49, and further from the hole 49 The structure passes through the space between the male screw 43 of the pump 40 and the inner surface 50 of the cylinder and communicates with the rear back pressure space 28 from the inlet side of the hole 49. Therefore, also in this case, the vicinity of the inlet of the hole 49 is an outlet of the back pressure oil supply passage 29, and the screw groove pump 40 of FIG.
[0068]
<Structural description common to the above thread groove pumps>
The number of threads of the male screw 43 and the female screw 45 is not limited to one, but may be plural. In the case of one thread, a cylindrical surface having a width of about 1 to 2 mm is formed at the apex of the thread of the male screw 43 or the female screw 45 in the axial direction. The width of the cylindrical surface can be reduced by increasing the number of the rows.
[0069]
A predetermined gap G1 between the apex of the thread of the male screw 43 and the cylindrical surface 42 or 50 separated from the apex of the screw thread, and a predetermined gap between the apex of the thread of the female screw 45 and the cylindrical surface 46 or 48 separated from the crest of the screw thread. G1 needs to be widened if the kinematic viscosity of the oil used is high, and must be narrow if the kinematic viscosity is low. In the vane rotary type gas compressor as in the present embodiment, the kinetic viscosity of the oil is higher than that of other types of gas compressors (90 cSt or more at 40 ° C., 18 cSt or more at 100 ° C.), and thus the gap G1 is A gap having a width of about 0.1 to 1.0 mm may be used.
[0070]
The cross-sectional shape of the male screw 43 and the female screw 45 is preferably a rectangular shape in which the wall surface of the screw groove is 90 ° or close to 90 °. If a general screw with a triangular cross section whose wall has a slope of 60 ° is used, the oil flowing force acts strongly not only in the direction of the rotation axis but also in the radial direction. It can be a factor in increasing power.
[0071]
<Operation description of thread groove pump 40 shown in FIG. 1 (FIG. 3) and FIG. 5 (FIG. 6)>
In each of the thread groove pumps 40 in these figures, the screw is not rotated, and the cylindrical surface is rotated by the rotation of the rotor shaft 7 so that the oil in the back pressure oil supply passage 29 is moved toward the rear back pressure space 28. Let it flow. That is, when the rotor shaft 7 starts rotating by the activation of the compressor, in the thread groove pump 40, the rotating cylindrical inner surface 42 or the rotating cylindrical inner surface 42 separated from the apex of the thread of the non-rotating male screw 43 or female screw 45 by a predetermined gap G1. A viscous flow in the same rotational direction as the rotor shaft 7 is generated in the oil interposed between the cylindrical surface 48 and the oil. The viscous flow of the rotating oil is transmitted to the oil in the thread groove of the male screw 43 or the female screw 45 by viscous friction, and the oil in the screw groove tries to rotate so as to be dragged. Then, when the oil in the screw groove rotates, the rotating oil collides with the wall surface of the non-rotating screw groove, so that the direction of the oil flows toward the rear back pressure space 28 along the wall surface of the screw groove. Is converted to
[0072]
As described above, the oil flows in the direction of the rear back pressure space 28, so that oil is sucked from the back pressure oil supply passage 29 on the upstream side of the thread groove pump 40 to the thread groove pump 40 side, and Oil is continuously and continuously delivered from the groove pump 40 to the rear back pressure space 28 on the downstream side thereof. For this reason, the oil is further supplied from the rear back pressure space 28 to the salary groove 34 through the communication hole 35.
[0073]
As described above, the oil is supplied to the sali-groove 34 one after another, so that the oil tends to enter the bottom of the vane groove 15 from the sali-groove 34. Then, at the same time as the oil enters the bottom of the vane groove 15, the vane 16 jumps out of the vane groove 15, and suction, compression, and discharge of the refrigerant gas are started.
[0074]
When the operation is described as above, it seems that it takes a considerable time from the rotation of the rotor shaft 7 until the vane 16 jumps out. However, the operation from the start of the rotation of the rotor shaft 7 to the jumping operation of the vane 16 is instantaneously performed. It is. This is because oil already exists in the rear back pressure space 28, the sali groove 34, and the bottom of the vane groove 15 before the rotation of the rotor shaft 7 starts. Since the oil is an incompressible fluid, the oil is started to be sent out from the thread groove pump 40, and at the same time, the sent out oil acts to push out the oil at the bottom of the vane groove 15 on the downstream side.
[0075]
When the suction, compression, and discharge of the refrigerant gas are started as described above, the discharge pressure of the discharge chamber 25 in the upper space of the oil reservoir 27 gradually increases due to the discharge pressure. This high pressure acts on the oil in the oil sump 27, the oil is further sent out from the oil sump 27 to the back pressure oil supply passage 29, and the oil is supplied from the oil sump 27 to the rear side via the oil supply hole 36 in the rear side block 6. Oil supply to the bearing 10 of the side block is started. The supply of oil from the oil reservoir 27 to the bearing 9 of the front side block is also started through the oil supply holes 36 of the rear side block 6, the cylinder 4 and the front side block 5.
[0076]
When the suction, compression, and discharge of the refrigerant gas are repeated several times, the pressure in the discharge chamber 25 further increases, and the high pressure also acts on the oil in the oil reservoir 27. Then, when the pressure of the oil in the oil reservoir 27 becomes higher than the pressure of the rear back pressure space 28 by 0.3 to 0.5 MPa or more, the back pressure on-off valve 30 of the back pressure oil supply passage 29 operates. That is, the compression spring 33 contracts, and the steel ball 32 comes into close contact with the sealing surface 31-2. Thereby, the back pressure on-off valve 30 is closed, and the back pressure oil supply passage 29 is closed. Then, the intermediate-pressure oil reduced in pressure is supplied to the bottom of the vane groove 15 via the clearances of the bearings 9 and 10 of the front and rear side blocks 5 and 6, and the gas compressor enters a steady state operation.
[0077]
<Description of the operation of the thread groove pump shown in FIGS. 4 and 7>
In each of the screw groove pumps 40 in these figures, the screw is rotated by the rotation of the rotor shaft 7, and the cylindrical surface separated from the apex of the screw thread is not rotated. It is caused to flow in the direction of the back pressure space 28. That is, when the rotor shaft 7 starts rotating by starting the compressor, the oil in the thread groove of the male screw 43 or the female screw 45 also rotates in the screw groove pump 40. However, rotation of the oil in the thread groove is suppressed by viscous frictional resistance of the non-rotating oil interposed between the apex of the thread and the cylindrical surface 46 or the cylindrical inner surface 50 separated by the predetermined gap G1. . By suppressing the rotation of the oil in the screw groove in this way, the oil in the screw groove flows toward the rear back pressure space 28 along the wall surface of the screw groove.
[0078]
As described above, the direction of the oil flow is directed to the rear back pressure space 28 side, so that the oil is sucked from the back pressure oil supply passage 29 on the upstream side of the screw groove pump 40 to the screw groove pump 40 side. The oil is continuously and continuously delivered from 40 to the rear back pressure space 28 downstream thereof. The subsequent operation is the same as that of the thread groove pump 40 shown in FIG. 1 (FIG. 3) and FIG. 5 (FIG. 6).
[0079]
By the way, in the thread groove pump 40 of FIGS. 1 (FIG. 3) and FIG. 5 (FIG. 6) and the thread groove pump of FIGS. 4 and 7, the common reason why oil flows inside the pump is as follows. It is. That is, the oil in the thread groove pump is divided into a rotating side and a fixed side, and viscous frictional resistance acts at a contact portion with each other. It flows along the wall.
[0080]
Accordingly, there is almost no difference between the thread groove pump 40 of FIGS. 1 (FIG. 3) and FIG. 5 (FIG. 6) and the thread groove pumps of FIGS. However, as shown in FIG. 1 (FIG. 3) and FIG. 5 (FIG. 6), a thread groove pump of a type in which the screw does not rotate but the uneven cylindrical surface separated from the apex of the screw thread rotates. In this case, since the weight balance in the circumferential direction of the rotating body can be kept uniform, vibration and noise during rotation due to slight deviation of the weight balance do not occur. On the other hand, in the case of a thread groove pump in which a screw rotates, as shown in FIGS. 4 and 7, it is difficult to keep the weight balance in the circumferential direction even when the screw is formed. Therefore, as the thread groove pump used in the gas compressor, a type in which the cylindrical surface rotates without rotating the screw is more preferable.
[0081]
In the above-described example of the thread groove pump, a case where one is a screw and the other is a cylindrical surface is shown, but a type in which a screw is formed on both the rotating side and the non-rotating side may be used.
[0082]
<Description of the structure to operate the thread groove pump more efficiently immediately after the compressor is started>
In order to efficiently draw out the pumping action of the thread groove pump 40 at the time of starting the compressor, it is better to store the oil in the oil sump 27 as much as possible. Immediately after the compressor is attached to the air conditioner system, the oil groove is filled with oil when the compressor is shipped, so that the thread groove pump 40 operates efficiently. However, after the operation of the compressor is repeatedly performed, the oil in the oil sump 27 moves to the low-pressure suction chamber 18 through the oil supply holes 36 to the bearings 9 and 10 after the compressor is stopped. A situation can occur in which no oil is stored.
[0083]
By the way, conventionally, it is a technical problem to suppress an increase in the starting torque due to the oil compression when the compressor is restarted in a state in which the oil is being delivered to the suction chamber 18 side and an increase in the starting noise accompanying the restart. The following measures have been proposed and implemented as countermeasures. For example, (1) a check valve is provided at the suction port 3-1 of the front head 3 communicating with the suction chamber 18, or (2) an open / close valve is provided at the inlet of the oil supply hole 36 to the bearings 9, 10. It is. By these means, even after the compressor is stopped, the oil is not sent out to the suction chamber 18 side, and is sufficiently stored in the oil sump 27.
[0084]
In the gas compressor according to the present invention, in order to make the thread groove pump 40 operate efficiently, it is not effective to use the above-mentioned means (1) or (2) together as means for storing oil in the oil sump 27. is there. However, as shown in FIG. 2, as a more preferable means, the discharge valve 22 and the discharge valve side opening end of the cylinder discharge hole 21 are so arranged that the discharge valve 22 does not completely block the cylinder discharge hole 21 when the compressor is stopped. There is a method of providing a minute gap G2 between the gap G2. In this case, when the discharge valve 22 is a reed valve having a plate thickness of 0.15 to 0.3 mm, the minute gap G2 is set to about 0.1 to 0.5 mm, and the cylinder discharge hole 21 during the operation of the compressor is reduced. It can be opened and closed.
[0085]
With the above configuration, immediately after the compressor is stopped, the cylinder discharge hole 21 is opened by the elastic force of the reed valve type discharge valve 22, whereby high-pressure refrigerant gas flows from the cylinder discharge hole 21 to the suction chamber 18 side. Due to the shift, the high pressure does not act on the oil reservoir 27 at the bottom of the discharge chamber 25. Accordingly, the oil can be sufficiently stored in the oil sump 27 even after the compressor is stopped, without providing a mechanism such as a check valve or an on-off valve as in the above-mentioned means (1) and (2). The thread groove pump 40 can be operated efficiently immediately after the next compressor start. In addition, the reed valve having a gap between the cylinder discharge hole 21 when the compressor is stopped, the speed at which the cylinder collides when the cylinder discharge hole 21 is closed during operation, and the speed of the collision with the cylinder discharge hole 21 when the compressor is stopped. Since it is slower than a reed valve having no gap between them, noise can be reduced.
[0086]
<Other configurations such as back pressure on-off valve>
As another configuration of the back pressure on-off valve 30, for example, a cylindrical valve body in which the sealing surface 31-2 has a 90 ° taper surface may be used instead of the steel ball 32. The seal surface 31-2 may have a taper surface other than 90 °.
[0087]
The back pressure oil supply passage 29 and the back pressure on-off valve 30 may be incorporated in the rear side block 6 instead of the oil separator 24 side.
[0088]
【The invention's effect】
According to the gas compressor according to the present invention, since the configuration provided with the thread groove pump that allows the oil in the back pressure oil supply path to flow by the rotation of the rotor shaft is employed, while appropriately maintaining the vane back pressure during steady operation, It has the following effects.
[0089]
(1) At the same time as the rotation of the rotor shaft is started by the start of the compressor, oil is supplied to the bottom of the vane groove by the pump action of the thread groove pump and the vane jumps out. Therefore, the normal compression operation of the refrigerant gas immediately after the start of the compressor. Can be started. When the normal compression operation starts, the back pressure on / off valve closes immediately and the oil supply to the bottom of the vane groove by the thread groove pump stops, so that no excessive vane back pressure is generated during the steady operation of the compressor, Can be prevented from rising. Therefore, the start-up of the cooling is quickened while maintaining the low fuel consumption of the vehicle.
[0090]
(2) By supplying oil to the bottom of the vane groove by the pump action of the thread groove pump as described above, a sufficient back pressure of the vane at the time of starting the compressor is ensured independently of the normal operation of the compressor. And the occurrence of chattering at the time of starting the compressor can be prevented, and the noise transmitted to the passenger compartment can be reduced.
[0091]
(3) Since the refrigerant gas is not supplied to the rear back pressure space when the compressor is started, there is no adverse effect on lubrication, and the durability of the compressor is improved.
[0092]
(4) Since the centrifugal force applied to the vane is not required when the vane pops out at the time of starting the compressor, the vane can be further reduced in weight, and the degree of freedom in designing the offset amount of the vane groove is increased.
[0093]
(5) When the vane jumps out when the compressor is started, it is hardly affected by the viscous resistance of the oil in the vane groove, so that it is possible to use a higher-viscosity oil, and the seal film leaks due to the oil film. (Internal leak) can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a gas compressor according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along line II-II of FIG.
FIG. 3 is an enlarged view of a thread groove pump employed in the gas compressor of FIG. 1 and a peripheral portion thereof;
FIG. 4 is an explanatory view of a modified example of the thread groove pump employed in the gas compressor of FIG. 1 and its peripheral portion.
FIG. 5 is a sectional view of a gas compressor according to another embodiment of the present invention.
FIG. 6 is an enlarged view of a screw groove pump employed in the gas compressor of FIG. 5 and a peripheral portion thereof;
FIG. 7 is an explanatory view of a modified example of the thread groove pump employed in the gas compressor of FIG. 5 and its peripheral portion.
[Explanation of symbols]
1 Compressor case
2 Compression mechanism
3 Front head
3-1 Suction port
4 cylinder
5 Front side block
5a Inlet
6 Rear side block
7 Rotor shaft
7F Front end of rotor shaft
7R Rotor shaft rear end face
8 rotor
9, 10 Bearing
11 Boss
12 Bearing
13 Pulley
14 clutch
15 Vane Groove
16 Vane
17 Compression chamber
18 Inhalation chamber
19 Inhalation passage
20 inlet
21 Cylinder discharge hole
22 Discharge valve
23 Discharge chamber
24 Oil separator
25 Discharge chamber
26 Separation filter
27 Oil pool
28 Rear back pressure space
29 Back pressure oil supply path
30 back pressure on-off valve
31-1 valve room,
31-2 Seal surface
32 steel ball
33 Compression spring
34 Rear side groove
35 Communication hole
36 Oil supply hole
37 Front side salary groove
38 High pressure oil supply path
39 annular groove
40 thread groove pump
41 Rotor shaft rear cylinder
42 Inner surface of cylinder of rotor shaft rear cylinder
43 Male screw
44 Bar-shaped protrusion of oil separator
45 female screw
46 Outer peripheral surface (cylindrical surface) of rod-shaped protrusion of oil separator
47 Rod-shaped protrusion of rotor shaft
48 Peripheral surface of cylindrical protrusion of rotor shaft (cylindrical surface)
49 holes
Inner surface of 50 holes (inner surface of cylinder)
G1, G2 gap

Claims (8)

A cylinder with a side block attached to the end face,
A rotor rotatably installed via a rotor shaft inside the cylinder,
A vane mounted in a vane groove formed on an outer peripheral surface of the rotor, and protruding and retracting from an outer peripheral surface of the rotor toward an inner peripheral surface of the cylinder;
The cylinder, a side block, a rotor and a small chamber inside the cylinder partitioned by a vane, and the rotation of the rotor repeatedly changes the size of the volume, and the compression chamber that sucks, compresses, and discharges the refrigerant gas by the volume change. ,
An oil reservoir in which the pressure of the refrigerant gas discharged from the compression chamber acts,
A rear back pressure space formed by a wall surface including a rear end surface of the rotor shaft,
A sali groove communicating with the rear back pressure space, and the vane communicating with a bottom of the vane groove in a section of a compression process from a suction stroke;
A high-pressure oil supply path that opens at one end of the oil reservoir and opens at the bottom of the vane groove after communication with the bottom of the vane groove and the saray groove is interrupted at the other end;
An inlet is open to the oil reservoir, and an outlet is a back pressure oil supply passage communicating with the rear back pressure space side,
It is provided in the middle of the back pressure oil supply path, opens when the difference between the pressure of the oil reservoir and the pressure of the rear back pressure space is equal to or less than a predetermined value, and closes when the difference exceeds a predetermined value. Back pressure on-off valve
A screw groove pump that is disposed in the middle of the back pressure oil supply path and downstream of the back pressure on-off valve and that causes oil in the back pressure oil supply path to flow by rotation of the rotor shaft. A gas compressor, comprising: The gas compressor according to claim 1, wherein the thread groove pump is provided on an inner peripheral side of the rotor shaft. The thread groove pump includes a cylindrical inner surface provided on the inner periphery of the rotor shaft, and a right-handed male screw provided inside the cylindrical inner surface with a predetermined gap from the cylindrical inner surface. The gas compressor according to claim 2, wherein: The thread groove pump comprises a left-handed female screw provided on the inner periphery of the rotor shaft, and a cylindrical surface provided with a predetermined gap between the female screw inside the female screw. The gas compressor according to claim 2, wherein: The gas compressor according to claim 1, wherein the screw groove pump is provided on an outer peripheral side of the rotor shaft. The thread groove pump comprises a cylindrical surface provided on the outer periphery of the rotor shaft, and a left-handed female screw provided at a predetermined distance from the cylindrical surface outside the cylindrical surface. The gas compressor according to claim 5, wherein The thread groove pump comprises a right-handed male screw provided on the outer periphery of the rotor shaft, and a cylindrical inner surface provided at a predetermined distance from the male screw outside the male screw. The gas compressor according to claim 5, wherein A cylinder discharge hole that discharges the refrigerant gas compressed in the compression chamber, and a discharge valve that opens and closes the cylinder discharge hole during operation of the compressor is provided.
The gas compressor according to claim 1, wherein the discharge valve opens the cylinder discharge hole when the compressor is stopped.

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