JPS6240151Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention relates to an improvement in the sliding valve structure of an oil-cooled screw compressor.

[Technical background]

In recent years, oil-cooled screw compressors equipped with a sliding valve that adjusts the compressed gas capacity have come into widespread use as compressors for refrigeration equipment. Screw compressors with built-in sliding valves have been known for a long time. Its basic structure and functions are shown in the drawings Figures 1, 2, and 3.
This will be explained using figures. In FIGS. 1 and 2, two hollow cylinders 1 and 2 arranged in parallel overlap each other at points 3 and 4 of a circular part of each axis-perpendicular cross section, and form a cylindrical shape with a gourd-shaped cross section. A casing 7 is formed having a working space 8 of holes 5-6. In the working space 8 of the cylindrical hole 5-6, there are two screw rotors that mesh with each other, namely a male rotor 9 and a female rotor 1.
0, and the shafts at both ends of each rotor are rotatably supported by bearings 11, 12, 13, 14, 15 and 16 as shown in FIG. A mechanical seal 18 is disposed on the drive side shaft portion 17 of the male rotor 9 to prevent leakage of lubricating oil from the bearing portion. A balance piston 20 is located at the opposite shaft end 19.
This structure reduces the thrust of the male rotor 9 in the axial direction. In FIG. 1, a part of the lower inner wall of the casing 7 is cut out at the lower part of the mesh between the male rotor 9 and the female rotor 10, and an inner wall 23 having a substantially semicircular cross section perpendicular to the axis is formed in the lower part. Cylindrical hole 5 in it
The overlapping point 4 of -6 is the tip, and the inclined curved surfaces 21 and 22 on both sides are part of the inner wall of the working space 8, and the lower inner wall 23 of the casing 7 is parallel to the rotor axis.
A slide valve 24 that can freely slide is provided. In FIG. 3, the suction port 25 is located at the left end of the working space 8 of the cylindrical hole of the casing 7, and the discharge port 26 is located at the right end.
It is equipped with The suction port 25 is the opening 2 of the suction chamber 27.
8, and the discharge port 26 communicates with a discharge chamber 29 and a discharge port 30. Gas is sucked into the working space 8 from the suction chamber opening 28 through the suction chamber 27 and through the suction port 25 as the rotor rotates. The volume defined by the meshing grooves of the rotors 9 and 10 and the cylindrical hole 5-6 is sequentially reduced by the rotation of the rotors to compress the gas and discharge it from the discharge port 26 through the discharge chamber 29 to the discharge port 30. The slide valve 24 is fixed to one end of a rod 31, and the other end of the rod 31 is fixed to a piston 32. As the discharge gas consumption fluctuates, hydraulic pressure is applied to one side of the piston 32 via oil supply holes 34 and 35 provided at both ends of the hydraulic cylinder 33 in response to a signal from a pressure or temperature detector (not shown). and piston 3
2 in either the left or right direction, and the slide valve 24 is moved via the rod 31. A guide groove 36 is provided in the bottom of the slide valve 24 in the axial direction.
6 starts at a position slightly away from the discharge side end face 37 and cuts through the suction side end face 38. A guide piece 39 that fits and slides in this guide groove 36 is arranged, and the guide piece 39 is connected to the holding pin 4 provided below the casing 7.
0, and serves to accurately maintain the circumferential position of the slide valve. Reference numeral 7' denotes a gutter-shaped guide with an arcuate cross section held on the discharge side end wall of the casing 7, which supports the slide valve 24 when it moves forward and backward into the discharge chamber 29. When the slide valve 24 moves to the position shown by the dashed line in FIG. Inlet 25 with opening 42
The gas sucked into the rotor groove from the opening 4
While passing through the second axial section, the compression action is not performed because the air returns to the suction chamber 27 via the return chamber 43. The compression process begins only when the tip line of the rotor groove reaches the end 38' of the sliding valve 24, which is indicated by a dash-dot line. In this case, the compression process is performed within the length L between the end face 38' and the discharge port 26 of the casing 7, and the capacity of the compressed gas is reduced compared to when the load is full. In this manner, due to pressure or temperature fluctuations, the position of the slide valve 24 is changed to change the suction cut-off position, thereby automatically adjusting the volume of discharged gas.

[Prior art and problems]

In an oil-cooled screw compressor having a sliding valve as described above, in order to facilitate the movement of the sliding valve,
Some slide valves have an oil groove on the outer periphery, into which a portion of the lubricating oil is injected and supplied into the bearing or working space. FIG. 4 is an exploded view of the sliding portion of a conventional sliding valve, viewed from the bottom, showing the arrangement of oil grooves. An oil groove 44 is provided in the circumferential direction near the discharge side end face 37, and oil grooves 45, 46, 4 on the axis communicate with the oil groove 44 in the axial direction on both sides with the guide groove 36 in between.
5' and 46' are provided, and the sliding valve 2 is inserted from the oil sump oil supply groove 49.
A part of the oil that is injected toward the working space 8 through the oil passages 47 and 48 in the oil reservoir 4 is branched from the oil sump oil supply groove 49 and flows into the oil grooves 45, 46, 45', and 4 on the axis.
6' for forced lubrication of the sliding surfaces. In this way, the sliding surface can slide smoothly,
Compressed gas is dissolved in the lubricating oil,
Since the pressure near the discharge side of the slide valve is high, the oil groove 44 can sufficiently provide lubrication and sealing effects, but the pressure is low near the suction side, and the gas in the lubricating oil expands.
The air returns to the suction side through the gap between the sliding surfaces through the return chamber 43 or the opening 42, reducing the amount of suction from the suction chamber opening 28 and deteriorating the performance of the compressor. Particularly in the case of compressors used in refrigerators, a considerable amount of refrigerant is dissolved in the oil, and when the oil pressure drops, more gas is generated from the oil, which goes to the suction side and recompresses, causing a new This results in a decrease in suction gas and significantly deteriorates the performance of the compressor. Therefore, in order to eliminate such defects,
In the device according to No. 19316, as shown in FIGS. 5 and 6, an oil groove 50 is provided in the circumferential direction near the discharge side end surface 37 of the sliding valve 54, and communicates with the oil sump oil supply groove 49 for lubricating oil. The oil groove 50 is extended in the axial direction to substantially the center 51, 51' of the slide valve 54 at both ends of the slide valve 54 in the circumferential direction, thereby forming a primary oil groove 50. The oil groove 5 is located slightly away from both ends 51 and 51' of the primary oil groove 50 and faces toward the suction side end surface 38.
2, 52' are provided, and these oil grooves 52, 52' are bent in the circumferential direction near the suction side end surface 38,
Furthermore, these oil grooves are extended in the axial direction along both sides of the guide groove 36, and the primary side oil groove 50 and the guide groove 36 are
A secondary oil groove 53 formed by connecting an end to the vicinity of the discharge side edge of the secondary oil groove 53 is disposed, and the secondary oil groove 53 is communicated with the oil sump oil supply groove 55. The oil sump oil supply groove 55 passes through the inside of the slide valve 54 and communicates with a recovery passage 56 that communicates with the working space 8 . In FIG. 5, the oil reservoir oil supply groove 55 provided in the slide valve 54 is always in communication with the passage 57 of the casing 7 even when the slide valve 54 moves, so that oil including oil after bearing lubrication can be collected. It was a big groove. A recovery passage 56 for recovering oil from the slide valve 54 into the working space 8 is connected to the inclined curved surface 22 of the slide valve 54.
By configuring the opening 60 so that it always communicates with the compression chamber after suction is closed regardless of the movement of the slide valve, the oil after lubricating the sliding surface of the slide valve 54 is transferred to the secondary side. The oil is collected through the oil groove 53 and recovery passage 56 into the compression chamber after the suction is closed, thereby eliminating a decrease in the suction volumetric efficiency of the compressor and responding to the pressure difference between the suction side end surface 38 and the discharge side end surface 37 of the upper surface of the sliding valve. By setting the primary oil groove 50 on the lower surface of the sliding valve to high pressure and the secondary oil groove 53 to low pressure to equalize the pressure distribution between the two, the sliding valve is held horizontally and the sliding valve is Partial contact with the outer periphery of the rotor due to lifting is avoided. In this way, in the invention of Japanese Patent Publication No. 57-19316, it is possible to improve the suction volumetric efficiency and prevent the sliding valve from floating. At the discharge end of the oil groove that is separated from the next oil groove, the supplied lubricating oil is part of the oil that is injected and supplied to the bearings and compression chambers, and is a pressure oil with a higher pressure than the discharge pressure of the compressed gas. Therefore, the sliding valve floats up and comes into partial contact with the outer periphery of the rotor, resulting in contact between the sliding valve and the rotor, resulting in damage to the rotor and/or the sliding valve.

【the purpose】

In order to more reliably prevent the sliding valve from floating, the present invention eliminates the force in the lifting direction of the sliding valve due to the pressurized injection supply oil applied to the oil groove on the discharge end side of the sliding valve. , there is no partial contact between the upper part of the sliding valve and the outer periphery of the rotor, making it possible to narrow the gap between the two as much as possible, increasing compression efficiency and suction volume efficiency, reducing power consumption and improving compression. The purpose is to improve the performance of the machine.

【composition】

The structure for achieving the above object of the present invention will be explained based on the illustrated embodiment. Two hollow cylinders 1 and 2 arranged in parallel are connected to each other by circular portions 3 and 4 formed in the cross sections perpendicular to the respective axes. A working space 8 in which overlapping cylindrical holes 5-6 are formed is formed in a casing 7 having an inlet 25 at one end and a discharge port 26 at the other end, and the working space 8 is formed in a casing 7 having an inlet 25 at one end and a discharge port 26 at the other end, and the working space 8 is interlocked with and rotates within the cylindrical holes 5-6. Two screw rotors 9 and 10 are arranged, and two cylindrical holes 5- in the casing 7 are arranged.
It is provided in the lower part of the casing 7 parallel to the rotor axis so as to form a part of the wall of the working space 8 at the lower position where the parts 6 overlap, and is perforated from the suction side end surface 38 to the vicinity of the discharge side end surface 37 in the axial direction of the bottom surface. guide groove 3
In the oil-cooled screw compressor, the oil-cooled screw compressor has a sliding valve 94 that is slidably disposed through the casing 7 of the sliding valve 94 and adjusts the compressed gas capacity by changing the closing position of the working space 8. Both ends of an oil groove 71 extending approximately the entire length in the circumferential direction near the discharge side end face 37 of the sliding face are connected to the suction side end face along the vicinity of both axial edges of the sliding face. 38, and then the oil grooves 72 and 73 are bent in the circumferential direction near the suction side end surface 38, and
These oil grooves 74, 75 are extended along the vicinity of both side edges of the guide groove 36 to form oil grooves 74', 75',
These oil grooves 74' and 75' are connected to an oil groove 71 provided near the discharge side end face 37 extending approximately the entire length in the circumferential direction to form a series of collection grooves 70, and this collection groove 70 is slidable. Recovery passage 56 passing through valve 94
is always in communication with the compression chamber in the casing 7 after suction is closed, and in the axial direction of the sliding surface that communicates with the pressurized lubricating oil supply passage 58 of the casing 7 at a position that does not intersect with the recovery groove 70. Elongated oil sump oil supply grooves 49a, 49b are provided in the oil sump oil supply grooves 49a, 49b, and the oil sump oil supply grooves 49a, 49b are always connected to the compression chamber after the suction is closed via recovery passages 47, 48, 81' passing through the inside of the slide valve 94. The oil grooves 74' and 76' are provided so as to communicate with each other and are provided along both side edges of the guide groove 36 and the vicinity of the both side edges.
It is characterized in that escape grooves 91 and 92 are formed in the vicinity of the oil groove 71, which extends approximately the entire length in the circumferential direction.

[Effect]

Therefore, according to the present invention, lubricating oil is supplied to the entire sliding surface from the oil reservoir oil supply grooves 49a, 49b which are elongated in the axial direction of the sliding surface and communicate with the pressurized lubricating oil supply passage 58 of the casing 7. is constantly collected into the compression chamber after suction is closed in the casing 7 through a series of collection grooves 70 arranged on almost the entire sliding surface and through a collection passage 56 penetrating the inside of the sliding valve 94, and is constantly collected into the compression chamber after suction is closed in the casing 7. Also, the entire sliding valve 94 does not float up, and the refrigerant dissolved in the lubricating oil introduced into the collection groove does not separate or expand, ensuring that the compression after suction is closed from the series of collection grooves 70 is ensured. They will always be collected back into the room. Furthermore, since one end of the relief grooves 91 and 92 penetrates and communicates with the suction side end surface 38, the pressure acting on the lower surface of the slide valve 94 becomes closer to the suction pressure (atmospheric pressure), and the compression pressure in the working space 8 causes the slide valve to A force pushing the slide valve 94 downward cancels out the force in the direction of lifting the slide valve 94.

【Example】

The details of the present invention will be explained below based on the illustrated embodiments (the overall structure of the oil-cooled screw compressor is the same as that described above, so the explanation will be omitted). In FIGS. 7 and 8, On the central axis of the bottom surface of the slide valve 94, there is a suction side end surface 38 in the axial direction.
A guide groove 36 is formed closer to the discharge side end face 37 . An oil groove 71 is provided in the vicinity of the discharge side end face 37 of the slide valve 94 along the side edge of the end face 37 and extends approximately the entire length in the circumferential direction. The oil grooves 72 and 73 are extended along the vicinity of both axial edges of the guide groove 36 to the vicinity of the suction side end face 38, and the oil grooves 72, 73 are further extended along the vicinity of the suction side end face 38 toward the vicinity of both longitudinal sides of the guide groove 36. Then, the oil grooves 74 and 75 formed near the suction side end face 38 are further connected to the guide groove 3.
A series of recovery grooves 70 are formed by extending along the vicinity of both side edges of the guide grooves 36 to the tips of the guide grooves 36, and further connecting the tips to oil grooves 71 formed near the discharge side end face. In the embodiment shown in the figure, two oil reservoir oil supply grooves are provided for supplying lubricating oil to the sliding surface of the sliding valve 94. That is, the oil sump oil supply groove 49a is located between the oil grooves 72 and 74', and the oil sump oil supply groove 49a is located between the oil grooves 75' and 73'.
b are each formed in the longitudinal direction between the oil grooves in an elongated substantially elliptical shape with a long side arranged in the direction of movement of the slide valve 94 so that lubricating oil can be received even when the slide valve 94 moves. It is set up. Further, oil grooves 74', 7 formed along both side edges of the guide groove 36 and the vicinity of both side edges of the guide groove 36.
Relief grooves 91 and 92 are provided along the longitudinal direction of the sliding surface between 5', that is, at equal positions on the left and right sides of the central axis of the sliding valve 94, respectively. This relief groove 9
One end of 1,92 is provided so as to pass through and communicate with the suction side end face of the sliding valve 94, and the other end is bored so as to reach the vicinity of the oil groove 71 formed near the discharge side end face 37 of the sliding face. It is formed by A sliding valve 94 is provided in the oil sump oil supply grooves 49a and 49b.
Openings 78, 79, 8 which are one end of a passage passing through the interior.
2 is provided. That is, the oil sump oil supply groove 49
An opening 78 faces the opening 7a, which injects and supplies pressurized lubricating oil to the compression chamber after the intake of the working space is closed through the recovery passage 47, and also opens the opening 7 of the oil sump oil supply groove 49a.
9 is provided with a recovery passage 48 that passes through the slide valve 94. In addition, as shown in FIG.
7 and 48 are both inclined curved surfaces 2 on the upper surface of the sliding valve 94
There are branch openings at 1 and 22. Oil sump oil supply groove 49a
As mentioned above, there are two passages penetrating through the slide valve 94, but the oil sump oil supply groove 49
There is one lubricating oil supply passage passing through the inside of the casing 7 leading to the point a (reference numeral 58). Furthermore, an opening 82 of a passage 81' that passes through the slide valve 94 and communicates with the recovery passages 47 and 48 within the slide valve 94 faces the oil sump oil supply groove 49b side, and the oil sump oil supply groove 49b The lubricating oil supply passage 58 communicates with an injection passage 80 which is provided in the casing 7 and is in open communication with the compression chamber after the suction is closed, while the lubricating oil supply passage 58 is connected to another injection passage 83 which is provided in the casing 7 and which is in open communication with the compression chamber after the suction is closed. The oil supplied to the lubricating oil supply passage 58 is communicated with the recovery passages 47 and 48 and the injection passage 8.
It is always injected and supplied into the compression chamber after suction is closed through the openings 0 and 83. Further, the opening 77 of the recovery passage 56, which always recovers lubricating oil from the recovery groove 70 to the compression chamber after the suction of the working space is closed, via the recovery passage 56 penetrating the slide valve 94, is located in the oil groove 75'.
It faces into the collection recess 76 formed near the discharge side end surface of the cylinder. Movement of the slide valve 94 changes the opening positions of the recovery passage 56 communicating with the recovery groove 70 and the recovery passages 47 and 48 communicating with the oil sump oil supply groove 49a, which open on the inclined curved surfaces 21 and 22 on the upper surface of the slide valve 94. Regardless of the situation, it is always located in a position that communicates with the compression chamber after suction is closed. In the above embodiment, the pressurized lubricating oil supplied through the lubricating oil supply passage 58 in the casing 7 is transferred to the recovery passage 4 within the oil sump oil supply groove 49a and the slide valve 94.
The lubricating oil overflows from the oil sump oil supply groove 49b through a passage 81' communicating with the oil supply grooves 7 and 48, lubricates the sliding surface with the lubricating oil that permeates the sliding surface, and flows into the collection groove 70. As a result, the pressure acting on the lower surface of the slide valve becomes closer to the suction pressure (atmospheric pressure), and the compression pressure in the working space creates a force that presses the slide valve downward to reliably prevent the slide valve from floating. Furthermore, the lubricating oil supplied from the lubricating oil supply passage 58 is transferred to the oil sump oil groove 49a and this oil sump oil groove 49a.
An oil sump oil supply groove 49b that communicates with the oil sump through a passage 81'.
It passes through the recovery passages 47, 48 penetrating the inside of the slide valve through the opening 78 or 79 provided in the opening 78 or 79 provided in the
The oil is injected and supplied to the compression chamber after suction closure, which is formed in the working space 8 by the two screw rotors 9 and 10 that rotate in mesh with each other above the slide valve 94 through the casing 7. After each function of cooling and sealing is achieved, it is discharged together with the compressed gas to the discharge port 30 via the discharge port 29 shown in FIG. 3. On the other hand, the lubricating oil collected in the series of collection grooves 70 is transferred from a collection recess 76 provided in communication with the grooves 70 to a collection passage 56 penetrating inside the slide valve 94 after the suction of the working space 8 is closed. The cooling effect and sealing effect of the compression chamber can be improved after the suction of the working space 8 is closed. The overall operation of the oil-cooled screw compressor is the same as that described above in the technical background section, so a description thereof will be omitted.

【effect】

As mentioned above, the present invention is provided in the lower part of the casing parallel to the rotor axis so as to form a part of the working space wall at the lower position where the two cylindrical holes in the casing overlap, and the suction is drawn in the axial direction of the bottom surface. Sliding with the sliding valve casing, which is slidably disposed through a guide groove drilled from the side end face to the vicinity of the discharge end face, and adjusts the compressed gas capacity by changing the closing position of the working space. Both ends of an oil groove are provided in the surface near the discharge side end face of the sliding face and extend to the vicinity of the suction side end face along the vicinity of both axially opposite edges of the sliding face, Next, the oil is bent in the circumferential direction near the suction side end face, and further extended along the vicinity of both side edges of the guide groove to reach approximately the entire length in the circumferential direction near the discharge side end face. The recovery groove is connected to the groove and formed in series, and the recovery groove is always communicated with the compression chamber after suction is closed in the casing via a passage passing through the inside of the sliding valve, and at a position that does not intersect with the recovery groove. An elongated oil sump oil supply groove is provided in the axial direction of the sliding surface that communicates with the pressurized lubricant supply passage of the casing, and the oil sump oil supply groove is always closed to suction via a passage that penetrates inside the slide valve. An oil groove is provided so as to communicate with the rear compression chamber, and between both side edges of the guide groove and an oil groove provided along the vicinity of the both side edges, one end of which penetrates into the suction side end face, and the other end of which is located near the discharge side end face. Since the escape groove is formed near the oil groove that extends approximately the entire length in the circumferential direction, the discharge side end face of the sliding surface also becomes part of the recovery groove, and lubricates the sliding surface. The pressurized oil prevents the sliding valve from floating up, making it possible to reliably prevent contact between the upper part of the sliding valve and the outer periphery of the screw rotor, and also to prevent recovery after the sliding surface of the sliding valve has been lubricated. The oil can be recovered into the compression chamber after suction is closed, thereby eliminating a drop in suction volumetric efficiency, reducing power consumption, and improving compressor efficiency. Further, between the both side edges of the guide groove and the oil groove provided along the vicinity of the both side edges, one end penetrates into the suction side end face, and the other end extends approximately the entire length in the circumferential direction near the discharge side end face. Since the relief groove is formed near the oil groove, the pressure acting on the lower surface of the slide valve at the suction side end face of the slide valve is more relaxed than before, and the slide valve is prevented from floating. I can do it. Thereby, it is possible to eliminate the possibility that the upper part of the slide valve and the outer periphery of the screw rotor will partially contact each other at the suction side end surface.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional oil-cooled screw compressor with a sliding valve, Fig. 3 is a sectional view taken along the - line, Fig. 2 is a plan sectional view taken along the - line of Fig. 1, and Fig. 3 is a cross-sectional view taken along the - line of Fig. 1. 4 is a developed view of the sliding surface of the conventional sliding valve 24, FIG. 5 is a developed view of the sliding surface of the sliding valve 54 of FIG. 6, and FIG. FIG. 5 is a sectional view taken along the line, both of which are related to the conventional example. 7 and 8 show an embodiment of the present invention, FIG. 7 is a developed view of the sliding surface of the sliding valve shown in FIG. 8, and FIG. 8 is a sectional view taken along the line -- in FIG. 7. It is. 1, 2...Hollow cylinder, 5, 6... Cylindrical hole, 7...
...Casing, 8... Working space, 9... Male rotor, 10... Female rotor, 23... Lower inner wall, 2
5... Suction port, 26... Discharge port, 47, 48...
Recovery passageway, 49a, b...oil sump oil supply groove, 56...
Recovery passageway, 57, 58... Lubricating oil supply passageway, 70
... Recovery groove, 71 to 75, 74', 75' ... Oil groove, 80, 83 ... Injection passage, 91, 92 ... Relief groove, 94 ... Sliding valve.

Claims (1)

[Claims for Utility Model Registration] A working space is formed by forming a cylindrical hole that overlaps with each other in a circular part formed in a cross section perpendicular to the axis of each of two hollow cylinders arranged in parallel, with an inlet at one end and an inlet at the other end. Two screw rotors are formed in a casing having a discharge port at an end and rotate in mesh with each other in the cylindrical hole, and a part of the working space wall is disposed at a lower position where the two cylindrical holes overlap in the casing. It is provided in the lower part of the casing parallel to the rotor axis so as to form a section, and is slidably disposed through a guide groove bored from the suction side end face to the vicinity of the discharge side end face in the axial direction of the bottom surface. In an oil-cooled screw compressor having a sliding valve that adjusts the compressed gas capacity by changing the closing position of the space, on the sliding surface of the sliding valve with the casing, near the discharge side end surface of the sliding surface. Both ends of the oil groove, which is provided almost the entire length in the circumferential direction, are extended along the vicinity of both axial edges of the sliding surface to the vicinity of the suction side end face, and then bent in the circumferential direction near the suction side end face. and further extending near both side edges of the guide groove,
A series of recovery grooves are formed by connecting to the oil groove extending approximately the entire length in the circumferential direction near the discharge side end face, and this recovery groove is constantly connected to the inside of the casing via a recovery passage passing through the inside of the slide valve. An elongated oil sump oil supply groove is provided in the axial direction of the sliding surface that communicates with the pressurized lubricating oil supply passage of the casing at a position that communicates with the compression chamber after suction is closed and does not intersect with the recovery groove, The oil reservoir oil supply groove is provided so as to always communicate with the compression chamber after suction is closed via a recovery passage passing through the inside of the slide valve, and both side edges of the guide groove,
The oil grooves are located between the oil grooves provided along the vicinity of both side edges, with one end penetrating through the suction side end face and the other end extending approximately the entire length in the circumferential direction near the discharge side end face. A sliding valve structure for an oil-cooled screw compressor characterized by the formation of relief grooves.