JPH027272Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a screw compressor that compresses gas by rotating a pair of male and female screw rotors that mesh with each other within a casing. A male rotor and a female rotor having a pair of thread grooves mesh with each other and rotate in opposite directions, and a tube-shaped rotor chamber is formed by the inner wall of the casing, the thread grooves, and end walls provided at both ends of the male and female rotors. As the male and female rotors rotate, the working space moves in the axial direction and increases or decreases, and gas is sucked in through the suction port provided on one end wall, compressed, and discharged from the discharge port provided on the other end wall. In the screw compressor, oil is supplied from the injection port to the rotor chamber working space for lubrication, cooling, and sealing, and at the same time, oil is supplied to bearings that support each of the rotors to lubricate the bearings. This invention relates to a screw compressor which improves the lubricating oil passage, ensures reliable lubrication and sealing at the discharge side end wall, reduces thrust force applied to male and female rotors, improves efficiency, and keeps costs low.

[Prior art] As a publicly known publication that improves the lubricating oil passage,
No. 50-17686 screw rotor machine is known. As shown in Fig. 1, this screw rotor machine has a male rotor 1 and a female rotor 2, which have a pair of screw grooves 3 and 4 provided on two parallel axes, and mesh with each other to rotate in opposite directions. A tube-shaped rotor chamber working space 8 formed by the inner wall 5' of the casing 5, the threaded grooves 3, 4, and end walls 6, 7 provided at both ends of the male and female rotors 1, 2 allows the male and female rotors 1, 2 to rotate. The gas is increased or decreased as it moves in the axial direction, and gas is sucked through the suction port 9 provided on one end wall 6.
The discharge port 10 (second
The oil is discharged from the rotor chamber working space 8 from the injection port 11 for lubrication, cooling, and sealing, and also radial bearings (suction side bearings) 12 that support the rotors 1 and 2 are mounted in the rotor chamber. The oil leaking from the working space 8 provides lubrication, while the thrust side bearing (discharge side bearing) 13 is supplied with oil from the oil supply port 20 for lubrication, etc.

In this screw compressor, a lubricating oil passage 16 is provided in the casing between the oil reservoir 15 of the thrust bearing 13 and the discharge side end wall 7, and the opening 17 of the end wall 7 of the passage 16 is
A recess 19 in the inner wall 5' of the casing 5 where the land 18 of the female rotor 2 facing the inlet communicates with the suction port 9.
The thread groove 4 between the land 18 and the succeeding land 18' cooperates with the edge 19' of the suction port 9.
when the trailing land 18' is in such a position that it completely seals from the edge 1 of the recess 19.
9', it approaches the land 18 and opens into the rotor chamber working space 8. Therefore, by forming the lubricating oil passage 16 within the casing 5, there is no need to provide external piping.
The cost can be kept low, and since the lubricating oil accumulated in the oil reservoir 15 after lubrication of the thrust bearing 13 (discharge side bearing) enters the working space of the rotor chamber after suction is completed, suction of gas from the suction port 9 is inhibited. , there is no risk of deterioration in suction efficiency.

[Problem to be solved by the invention] The opening 17 on the lubricating oil passage side 16 is such that the land 18' is located at the edge 1 of the recess 19 in the casing inner wall 5'.
9' and compression starts, the land 18' opens into the rotor chamber working space 8 after the compression starts until it passes through the opening 17, so that the pressure in the rotor chamber working space after the compression starts is as high as the above. A large thrust force acts on the discharge side shaft ends 1' and 2' of the male and female rotors 1 and 2 through the opening 17 and the oil reservoir 15, and a large thrust force acts on the male and female rotors 1 and 2, and the rotor at the suction side end wall 6 This has the disadvantage of making thrust bearings expensive for heavy loads in order to prevent seizure.

The purpose of this invention is to have a male rotor and a female rotor that have a pair of thread grooves provided on two parallel axes mesh with each other and rotate in opposite directions. As the male and female rotors rotate, the tube-shaped rotor chamber working space formed by the male and female rotors increases or decreases in the axial direction. The oil is discharged from a discharge port provided on the other end wall, and oil is supplied from the injection port to the working space of the rotor chamber for lubrication, cooling, and sealing, and oil is supplied to the bearings that support each of the rotors. In screw compressors that perform lubrication, this reduces the thrust force acting on the male and female rotors, eliminates the cost-increasing external piping that was formed for the lubricating oil passage, and prevents the end walls of the rotor and casing from seizing. The purpose is to further improve compression efficiency.

[Means for Solving the Problems] In the present invention, a male rotor and a female rotor having a pair of thread grooves provided on two parallel axes mesh with each other and rotate in opposite directions, and the inner wall of the casing and the thread grooves mesh with each other and rotate in opposite directions. and end walls provided at both ends of the male and female rotors, and the tube-shaped rotor chamber working space increases or decreases by moving in the axial direction as the male and female rotors rotate,
Gas is inhaled through the suction port provided on one end wall, compressed, and discharged from the discharge port provided on the other end wall.
Supplying oil from the injection port to the rotor chamber working space,
In a screw compressor that performs lubrication, cooling, and sealing as well as lubricating bearings that support each of the rotors to lubricate the bearings, an oil reservoir that communicates with the oil reservoir of the discharge side bearing and opens in the discharge side end wall. A lubricating oil passage is bored in the casing, and when the seal line of the male and female rotors reaches the edge of the recess that communicates with the suction port provided on the inner wall of the casing, the seal line of the preceding female rotor and the seal line of the preceding female rotor are sandwiched between the seal lines. An opening on the discharge side end wall of the lubricating oil passage is formed at a position within approximately 1/2 pitch in both directions of the seal line of the female rotor that is adjacent to and follows the seal line.

[Function] When the male and female rotors rotate and the seal line of the rotor reaches the edge of the recess that communicates with the suction port, gas is trapped in the rotor chamber working space, and is then sequentially compressed as the rotor chamber working space decreases. , the compressed gas is discharged from the discharge port. At this time, oil is supplied from the opening immediately before the rotor chamber working space is closed.

[Example] In FIGS. 3 to 5, the screw compressor 21 has a lubricating oil injection port 22 connected to a casing 23a.
A large amount of oil is injected into the rotor chamber working space 24 during the compression process in the casing 23a to remove the heat generated during compression, and between the helical lands 27 and 28 of the male and female rotors 25 and 26. By sealing the gap between both rotors and the inner wall 23a' of the casing 23a with oil to reduce leakage of compression gas and provide lubrication, the male and female rotors 25 and 26 can be directly engaged without providing a timing gear between the two rotor shafts. Configured to be rotatable. Each of the rotors 25 and 26 is supported by a suction side bearing 31 provided on the casing 23a on the side of the suction side end wall 29 and a discharge side bearing 32 provided on the casing 23b on the side of the discharge side end wall 30, respectively. The suction side bearing 31 is a radial bearing, and the discharge side bearing 32 is a thrust bearing, which sucks working gas from one axial end, compresses it, and discharges it to the other axial end. The rotors 25 and 26 are provided as described above in order to generate a pressure difference between the two ends, and to receive a thrust load acting on the entire rotors 25 and 26 due to the pressure difference.

On the other hand, the lubricating oil path is connected to a receiver tank 36 connected to the discharge port 35 and the receiver tank 3
After the oil separated by the oil separator 37 built into the casing 6 is cooled by the oil cooler 38, it is pressurized by the internal pressure of the oil pump (not shown) or the receiver tank 36, and is forcibly removed from the bearings 31, 32 provided in the casings 23a, 23b. 1st and 2nd passages 39, 40 leading to
and a third passage 41 leading to the lubricating oil injection port 22.

A presser cover 42 is provided in the mounting hole of the discharge side bearing 32, and an oil reservoir 43 is formed. The discharge side end wall 30 communicates with the oil reservoir 43 of the discharge side bearing 32.
A lubricating oil passage 44 that opens to the casing 23b is formed in the casing 23b. The discharge side end wall 3 of this lubricating oil passage 44
The 0-side opening 45 has a seal line c on the female rotor 26 side shown in FIG.
Edge 4 of recess 47 communicating with suction port 46 provided at a'
7'(c' in the figure), the seal line d of the preceding female rotor sandwiching the seal line c (d' in the figure)
and a seal line b adjacent to and subsequent to the seal line c.
It is formed at a position within approximately 1/2 of the pitch p in both directions of the moved position (b' in the figure).

Further, reference numeral 48 designates a recovery passage for oil that lubricates the suction side bearing 31, which is opened in the suction side end wall 29. Furthermore, the fifth
The figure is a developed view of the inner wall 23a' of the casing 23a, and in FIG.
3a' shows the recess 47, a, b, c, d,
e and f indicate the seal lines between the land 28 of the female rotor 26 and the casing inner wall 23a', and g, h, i, and j indicate the seal lines between the land 27 of the male rotor 25 and the casing inner wall 23a', respectively.

The embodiment of the present invention has the above-mentioned configuration, and its effects will be explained next.

In FIGS. 3 and 5, now the male rotor 25
When the shaft end 49 of the male rotor 25 and the female rotor 26 are rotated by an appropriate drive mechanism, the land 2
7 and 28 are engaged with each other, and the male rotor 25 and the female rotor 26 rotate in opposite directions. By the rotation of both screw rotors 25 and 26, working gas is sucked through the suction port 46 and the land 2 of the male rotor is
Thread groove 50 between 7 and 27 and land 2 of female rotor
Thread groove 51 between 8 and 28 and casing inner wall 23
It is confined in the rotor chamber working space 24 formed by a' and the end walls 29, 30 at both ends of the male and female rotors, is sequentially compressed, and is discharged from the discharge port 35. That is, in FIG. 5, both screw rotors 25,
26, each seal line moves upward in the drawing, and when the seal lines c and h reach the edge 47' of the casing inner wall recess 47, that is, the seal line c moves upward in the drawing.
When moving to position c', gas is trapped in the rotor chamber working space between the seal lines c, d, h, and i, and is then sequentially compressed as the rotor chamber working space decreases, and the seal lines d and i are connected to the discharge port 35. When it reaches
The compressed gas is discharged to the discharge port 35. At this time, just before the seal line c moves to position c' and confines the gas, lubricating oil is injected into the rotor chamber working space 24 from the injection port 22 provided in the casing 23a to seal, cool, and lubricate each part. After the above actions, the compressed gas is discharged from the oil separator 3 from the discharge port 35.
7 is fed into the receiver tank 36 which contains 7.

On the other hand, lubricating oil is pressurized in the suction side bearing 31 and the discharge side bearing 32 by the internal pressure of an oil pump or receiver tank 36 (not shown), and the passage 39,
40. In particular, the lubricating oil on the discharge side is supplied to the discharge side bearing 32 via the annular groove 34 provided in the cylindrical spacer 33 of the male and female rotor 25, 26 shafts, and after lubricating the discharge side bearing 32, etc. The lubricating oil is injected into the reservoir 43 and sent to the opening 45 via the lubricating oil passage 44 . A part of the oil discharged from this opening 45 lubricates the discharge side end wall 30, and most of the oil is used in the rotor chamber working space 24 where the opening 45 opens.
is directly discharged.

In FIG. 5, the rotor chamber working space opened by this opening 45 is the rotor chamber working space between the seal lines c, d, h, and i in the vicinity where the seal lines c and h reach the edge 47' of the recess 47 on the inner wall of the casing. The volume of the working space is expanded sequentially, and it is also the working space immediately before ending inhalation or immediately after starting compression. For this reason,
The rotor chamber working space is a casing inner wall recess 47.
An opening 45 and a lubricating oil passage 4 are provided at the discharge side shaft ends 52 of the male and female rotors, which communicate with the suction port 46 through the oil reservoir 43 of the discharge side bearing 32 and project into the oil reservoir.
Almost the same pressure as that of the suction port acts through 4.
Then, when the seal lines c and h reach the edge 47', that is, when the seal line c reaches the c' position, the rotor chamber working space between the seal lines c, d, h, and i finishes suction. At this time, as the seal lines c, h approach the edge 47', that is, just before the rotor chamber working space is closed, the gaps between the seal lines c, h and the edge 47' become smaller, and therefore, the gap between the seal lines c, h and the edge 47' becomes smaller. Recess 47
The amount of oil leaking to the suction port 46 through the suction port 46 is extremely small, and the inhibition of gas suction into the suction port 46 by this oil is extremely small. Further, the gas contained in the oil discharged from the opening 45 eliminates the negative pressure in the working space of the rotor chamber at the end of suction, thereby increasing the filling efficiency.

Furthermore, as explained in FIGS. 1 and 2, conventionally, when the seal lines c and h reach the edge 47', the opening 17 of the discharge side end wall of the lubricating oil passage is opened close to the seal line d. Therefore, after the seal lines c and h pass the edge 47', the opening 17 remains until they pass through the opening 17.
opens into the rotor chamber working space between the seal lines c, d, h, and i after the start of compression, and therefore, oil leakage to the suction port 46 can be reliably prevented, but the rotor chamber working space after the start of compression pressure at the opening 17 of the lubricating oil passage
This pressure acts on the oil reservoir of the discharge side bearing through the pressure, and this pressure also acts on the discharge side shaft ends of the male and female rotors, and a large thrust force is applied to the male and female rotors.

On the other hand, in the embodiment of the present invention, as described above,
Since the pressure acting on the discharge side shaft end of the male and female rotors can be made almost the same as that on the suction port, the thrust force applied to the male and female rotors can be reduced, and very little oil leaks to the suction port, improving suction efficiency. can also be improved.

[Effects of the invention] As described above, the present invention provides a lubricating oil passage in the casing that communicates with the oil reservoir of the discharge side bearing and opens at the end wall of the discharge side, and also connects the seal wires of the male and female rotors to the inner wall of the casing. Immediately in front of the recess that communicates with the provided suction port, the seal line is located within approximately 1/2 pitch with respect to both the seal line of the preceding female rotor and the seal line of the female rotor that follows the seal line. With the configuration in which the opening is provided at the position,
First, the pressure that acts on the oil reservoir of the discharge side bearing of the male and female rotors can be made almost the same pressure as the suction port, and the pressure that acts on the shaft end of the male and female rotor discharge side can be reduced, which reduces the pressure that acts on the rotor. Thrust force can be reduced. Second, since the internal passage system is adopted in which the lubricating oil passage is formed by drilling into the casing, piping parts and their installation are unnecessary, and the cost is reduced. Thirdly, by opening the opening of the lubricating oil passage in the discharge side end wall, sufficient oil can be supplied between the discharge side rotor end faces, and seizing of both can be prevented. Fourthly, it is possible to prevent obstruction of gas suction into the suction port due to oil leakage to the suction port after lubricating the discharge side bearing, and to prevent a decrease in suction efficiency, and also to improve filling efficiency.
Fifth, since the opening of the lubricating oil passage is formed near the seal line of the female rotor where the land teeth are thin, the time that the land blocks the opening is shortened, and the oil is efficiently transferred to the working space of the rotor chamber. can be discharged.

As described above, it is possible to provide an efficient screw compressor that has many practically beneficial effects.

[Brief explanation of the drawing]

1 and 2 show a conventional screw rotor machine.
The figure is a sectional view taken along line b-b in Fig. 1, Figs. 3 to 5 show embodiments of the present invention, and Fig. 3 is a sectional view taken along c-c in Fig.
4 is a sectional view taken along line dd in FIG. 3. Figure 5 shows the casing 2 shown in Figures 3 and 4.
3a is a developed view of the inner wall 23a'. 22... Lubricating oil injection port, 23a, 23b... Casing, 24... Rotor chamber working space, 25...
Male rotor, 26... Female rotor, 29, 30... End wall, 31, 32... Bearing, 35... Discharge port, 43
... Oil reservoir, 44 ... Lubricating oil passage, 45 ... Opening, 46 ... Suction port, 47 ... Recess, 47' ...
Edge, a, b, c, d, e, f, g, h, i, j...
...Seal line, p...pitch.

Claims (1)

[Scope of utility model registration request] A male rotor and a female rotor having a pair of thread grooves provided on two parallel axes mesh with each other and rotate in opposite directions, and the thread grooves are formed by an inner wall of the casing and an end wall provided at both ends of the male and female rotors. As the male and female rotors rotate, the tube-shaped rotor chamber working space increases or decreases in the axial direction, and gas is sucked in through the suction port provided on one end wall, compressed, and transferred to the other end wall. Screw compression that discharges oil from a provided discharge port and supplies oil from an injection port to the working space of the rotor chamber for lubrication, cooling, and sealing, and also supplies oil to bearings that support each rotor to lubricate the bearings. In the machine, a lubricating oil passage that communicates with the oil reservoir of the discharge side bearing and opens at the discharge side end wall is bored in the casing, and a recess is formed in which the seal wire of the male and female rotors communicates with the suction port provided on the inner wall of the casing. When the edge is reached, the lubrication is applied to a position within approximately 1/2 pitch in both directions of the seal line of the leading female rotor sandwiching the seal line and the seal line of the succeeding female rotor adjacent to the seal line. A screw compressor characterized in that an opening is formed on the discharge side end wall side of the oil passage.