JP6948206B2 - Oil-cooled screw compressor - Google Patents

Description

The present invention relates to an oil-cooled screw compressor that employs a lip seal as a shaft seal device, and prevents abnormal wear and seizure of the lip seal seal member (seal lip member), enabling long-term use of the lip seal. Regarding the oil-cooled screw compressor.

The oil-cooled screw compressor is provided with a drive shaft that penetrates the casing and protrudes to the outside of the machine, and the fluid inside the casing does not leak to the outside of the machine at the part where this drive shaft penetrates the casing. As described above, a shaft sealing device for sealing the penetrating portion (shaft sealing portion) is used.

As an example of the oil-cooled screw compressor using such a shaft sealing device, the oil-cooled screw compressor 200 shown in FIG. 7 will be described as an example.

This oil-cooled screw compressor 200 is a two-stage compressor, and is a high-pressure stage in which the discharge port 226 of the low-pressure stage compressor main body 220 arranged in the upper stage of the paper surface is arranged in the lower stage of the paper surface via the intermediate stage passage 250. By communicating with the suction port 235 of the compressor main body 230, the compressed gas compressed by the low-pressure stage compressor main body 220 can be further compressed by the high-pressure stage compressor main body 230.

The low-pressure stage and high-pressure stage compressor bodies 220 and 230 have a pair of male and female screw rotors 223, 223': 233, 233'in the rotor chambers 222 and 232 formed in the casings 221,231, respectively. In FIG. 7, the other rotor 223'233'is located on the back side of the paper surface of the one rotor 223, 233) and is rotatably accommodated, and the screw rotor 223, 223': 233,233. 'The rotor shafts 224 and 234 of one of the screw rotors 223 and 233 are configured so that the rotational driving force from a drive source (not shown) such as an engine or a motor can be input.

In order to enable such input of rotational driving force, the rotor shafts 224 and 234 of each of the above-mentioned low-pressure stage and high-pressure stage compressor bodies 220 and 230 are illustrated via the speed increasing device 240. It can be connected to no drive source.

A casing (gear case) 241 of the speed increasing device 240 is attached to one end side of the casings 221, 231 of the low-pressure stage and high-pressure stage compressor bodies 220 and 230, and the low-pressure stage compressor body 220 and high-pressure stage compression are provided in the gear case 241. With respect to the driven gears 242 and 243, the driven gears 242 and 243 are attached by inserting the ends of one of the rotor shafts 224 and 234 of the machine body 230, and both of these two driven gears 242 and 243 mesh with each other. A drive gear 244 formed with a large diameter is accommodated, and a drive shaft 245 attached to the drive gear 244 is extended outside the gear case 241 to form a speed increasing device 240.

Therefore, by inputting the rotational driving force from a driving source (not shown) such as an engine or a motor to the driving shaft 245 projecting from the gear case 241 to the outside of the machine, the rotational driving force generated by the driving source is increased. After speeding up by the speed device 240, it is configured so that it can be input to the rotor shafts 224 and 234 of the compressor main bodies 220 and 230 of the low pressure stage and the high pressure stage.

Further, in the oil-cooled screw compressor 200, the space inside the gear case 241 forms a part of the intermediate stage passage 250, and the drive shaft 245 provided in the speed increasing device 240 is the gear case 241. Since the drive shaft 245 extends inside and outside, a shaft seal portion 214 is formed at a portion where the drive shaft 245 penetrates the gear case 241, and a mechanical seal 212 is adopted as a shaft seal device for sealing the shaft seal portion 214 for compression. It prevents the fluid and lubricating oil from leaking out of the machine (Patent Document 1).

Japanese Patent No. 6066069

A mechanical seal 212 is used for the shaft sealing device of the drive shaft 245 of the oil-cooled screw compressor 200, but generally, an oil seal is used for the shaft sealing device in addition to the mechanical seal.

Mechanical seals have a longer life than oil seals and are suitable for harsh usage conditions such as when the pressure of the fluid to be sealed is high. There are inherent problems such as taking up space.

On the other hand, in recent years, lip seals using Teflon resin (ethylene tetrafluoride resin), which has excellent heat resistance and abrasion resistance, as a seal member have become general-purpose and have been adopted as a shaft seal device for a compressor body. ing.

FIG. 8 is a diagram showing an example of the conventional lip seal 300. As shown in the figure, an annular lip holding portion 301 made of a synthetic resin containing a metal ring 303 for imparting rigidity is inserted into the casing 330. It is fitted and fixed, and the seal lip 302 at the tip of the lip holding portion 301 is always in sliding contact with the outer peripheral surface of the drive shaft 320 with appropriate elasticity.

As mentioned above, the lip seal has a simple structure, is superior to other oil seals in heat resistance and wear resistance, and is superior to mechanical seals in terms of assembling property and cost. As a shaft sealing device, it is being adopted as an alternative to mechanical seals.

However, for example, in the lip seal 300 shown in FIG. 8, when the pressure inside the machine (inside the casing 330) of the lip seal (shaft sealing device) is high and the pressure difference between the inside and outside (atmospheric pressure) is large. The force (pressing force) that the tip of the seal lip 302 tightens toward the center of the drive shaft 320 increases, and the seal lip 302 bulges and deforms from the inside of the machine to the outside of the machine, so that the contact area with the drive shaft 320 Increases, the sliding resistance between the outer circumference of the drive shaft 320 and the seal lip 302 increases, abnormal wear of the seal lip 302 causes seizure due to heat generation, and the life of the lip seal 300 is shortened. Further, there arises a problem that the power for rotating the drive shaft 320 increases.

From this, when the pressure inside the casing provided with the shaft sealing device is higher than the pressure outside the machine, the inside of the gear case 241 is intermediate, for example, as in the oil-cooled screw compressor 200 of Patent Document 1 described above. It was difficult to change the shaft sealing device from the mechanical seal to the lip seal in the compressor body, which forms a part of the step passage 250 and the pressure inside the gear case 241 is higher than that outside the machine.

On the other hand, in the oil-cooled screw compressor, the present invention is a case where the pressure inside the casing (inside the machine) provided with the shaft sealing device is higher than that outside the machine, and the pressure difference between the inside and the outside of the machine is large. However, a lip seal is used for the shaft sealing device, and the purpose is to prevent the sealing member (seal lip 302) of the lip seal (300) from being abnormally worn or seized.

The means for solving the problem are described below together with the reference numerals used in the embodiment of the invention. This reference numeral is for clarifying the correspondence between the description of the claims and the description of the form for carrying out the invention, and needless to say, it is used in a restrictive manner in the interpretation of the technical scope of the present invention. It is not something that can be done.

In order to achieve the above object, the oil-cooled screw compressor 1 of the present invention uses a pair of male and female screw rotors 23, 23'(23, 23': 33, 33'in the embodiment of FIG. 1). , The rotor chamber 22 (22, 32 in FIG. 1) formed in the casing 21 (21, 31, 41 in FIG. 1) is rotatably housed in the rotor chamber 22 (22, 32 in FIG. 1), and both screw rotors 23, 23'(in FIG. 1). The gas to be compressed is sucked into the rotor chamber 22 (22, 32 in FIG. 1) by the meshing rotation of 23, 23': 33, 33'), and the lubricating oil is sucked into the rotor chamber 22 (22, 32 in FIG. 1). From the compressor main body 2 (2, 3 in FIG. 1) and the compressor main body 2 (2, 3 in FIG. 1) that compress the gas to be compressed and discharge the gas-liquid mixed fluid of the compressed gas and the lubricating oil. The discharged gas-liquid mixed fluid is introduced to separate the compressed gas and the lubricating oil, and the oil separator (receiver tank) 88 that stores the separated lubricating oil and the lubricating oil stored in the oil separator 88 are cooled. The oil cooler 89 and the oil supply pipe 81 for supplying the lubricating oil cooled by the oil cooler 89 to each part of the compressor main body 2 (2, 3 in FIG. 1) are provided, and the compressor main body 2 (in FIG. 1) is provided. A drive shaft 45 that opens a shaft hole in the wall surface of the casing 21 (cover 12 in FIG. 1) and connects to the drive source is inserted into 2 and 3), and the shaft hole and the outer periphery of the drive shaft 45 are connected to each other. An oil-cooled screw compressor 1 provided with a shaft sealing device 5 for preventing the gas inside the machine having a relatively high pressure from leaking to the outside of the machine having a relatively low pressure.
The shaft sealing device 5 has a tip end facing the inside of the machine in the axial direction of the drive shaft 45, and has at least two or more seal lips that are in sliding contact with the outer periphery of the drive shaft 45 at intervals (53, 54 in FIG. 2, FIG. 4). In the embodiment of 53a, 53b, in the embodiment of FIG. 5, 53a', 53b', 53c') is provided, and at least one refueling partition formed between the adjacent seal lips 53 and 54 is provided. A lip seal 50 having the seal lips 53, 54 is provided so as to have a space 55 (see FIG. 2, 55a in the embodiment of FIG. 4, 55a', 55b' in the embodiment of FIG. 5) (FIG. 2). In the embodiment of FIG. 4, one lip seal 50 having 2 seal lips 53 and 54 is installed. In the embodiment of FIG. 4, two lip seals having 1 seal lips 53a and 53b are installed 50a and 50b, respectively. In the embodiment of FIG. 5, three lip seals having one seal lip 53a', 53b', 53c' are installed 50a', 50b', 50c', respectively.),
The lubricating oil storage portion of the oil separator 88 and the lubrication space 55 are communicated with each other via the lubrication pipe 81, and at the same time.
Of the rotor chamber 22 in the compressor main body 2, a space having a pressure relatively low with respect to the pressure in the space in the casing 21 (41 in FIG. 1) provided with the shaft sealing device 5 and the refueling. is communicated via the space 55 transgressions regulating pressure pipe 83, the pressure of the oil supply space is at a low pressure relative to the pressure of the inboard and characterized in that it is adjusted to a high pressure to the pressure of the outboard (Claim 1).

The shaft sealing device 5 may include a lip seal 50 (see FIG. 2) in which two or more seal lips 53 and 54 are integrally formed (claim 2).

The shaft sealing device 5 includes two or more lip seals having one seal lip (50a, 50b in the embodiment of FIG. 4, 50a', 50b', 50c' in the embodiment of FIG. 5). (Claim 3).

Further, in the oil-cooled screw compressor 1 of the present invention, the compressor main body is a low-pressure stage compressor main body 2, a high-pressure stage compressor main body 3, a discharge port 26 of the low-pressure stage compressor main body 2, and the high-pressure stage. An intermediate stage passage 19 that communicates with the suction port 35 of the compressor body 3 is provided (FIG. 1).
The refueling pipe 81 is a refueling location of the low-pressure compressor main body 2 via the lubricating oil storage portion of the oil separator 88 and the refueling passage 16 (in the rotor chamber 22 in the embodiment of FIG. 1). , Communicating with the refueling point of the high-pressure stage compressor main body 3 (in the rotor chamber 32 in the embodiment of FIG. 1) and the refueling space 55 of the shaft sealing device 5.
The pressure adjusting pipe 83 may communicate with the oil supply space 55 of the shaft sealing device 5 and the rotor chamber 22 of the low pressure stage compressor main body 2 via the pressure adjusting passage 18 (claim 4).

Further, the compressor main body accelerates the rotation of the drive shaft 45 connected to the drive source and transmits the speed-increasing gear to the low-pressure stage compressor main body 2 and the high-pressure stage compressor main body 3 in the gear case 41. The discharge port 26 of the low-pressure stage compressor main body 2 and the suction port 35 of the high-pressure stage compressor main body 3 are connected to the space inside the gear case 41, and the gear case 41 is the casing 21 (21 in FIG. 1). , 31, 41) and a part of the intermediate stage passage 19, a shaft hole is opened in the wall surface of the gear case 41 to insert the drive shaft 45, and the shaft hole and the outer periphery of the drive shaft 45 The shaft sealing device 5 may be provided between the two (claim 5).

Of the plurality of seal lips 53 and 54 provided in the shaft sealing device 5, the length of the seal lip 53 (seal member 53a) arranged most inside the machine in the axial direction of the drive shaft 45 is set to the length of the other seal lips 54. It may be formed shorter than the length of (seal member 53b) (claim 6).

Further, it is preferable that the thickness of the seal lip 53 (seal member 53a) arranged most inside the machine is made thicker than the thickness of the other seal lip 54 (seal member 53b) (see FIG. 6) (claim). 7).

The pressure adjusting pipe 83 may be provided with a throttle 84 having a narrow flow path area (claim 8).

According to the configuration of the present invention described above, the shaft sealing device 5 of the oil-cooled screw compressor 1 of the present invention has the inner casing (inside the machine) side and the casing by two seal lips 53 and 54 adjacent to each other at intervals. A refueling space 55 partitioned from the outside (outside the machine) side (atmospheric pressure) is formed. Then, since the high-pressure lubricating oil is introduced into the refueling space 55 from the oil separator 88 via the refueling pipe 81, the pressure in the refueling space 55 rises. As a result, the magnitude of the pressure inside the machine, the refueling space 55, and the outside (atmospheric pressure) becomes the pressure inside the machine> the pressure at the refueling space 55> the pressure outside the machine (atmospheric pressure). Even if the pressure difference between the inside of the machine and the outside of the machine is large due to the high pressure, the pressure difference between the inside of the machine and the refueling space 55 and the pressure difference between the refueling space 55 and the outside of the machine are the same as the inside of the machine. Since it is smaller than the pressure difference on the outside of the machine, the bulging deformation of each seal lip 53, 54 caused by a large pressure difference is suppressed, and the force (pressing force) that each seal lip 53, 54 tightens the drive shaft due to the pressure difference is suppressed. Suppress and reduce sliding resistance.

Further, since the seal lip 53 arranged most inside the machine is lubricated by the lubricating oil transmitted from the inside of the machine along the outer circumference of the drive shaft 45 and the lubricating oil in the lubrication space 55 on the outside of the machine, the outer circumference of the drive shaft 45 is provided. Friction with and is reduced.

Further, since the lubricating oil introduced into the oil supply space 55 is collected in the rotor chamber 22 via the pressure adjusting pipe 83, the oil separator 88 to the oil cooler 89 in the oil supply space 55 (between the seal lips 53 and 54). Lubricating oil that has passed through and cooled is sequentially supplied to cool the seal lips 53 and 54.

As described above, the oil-cooled screw compressor 1 of the present invention can effectively prevent abnormal wear and seizure of the seal lips 53 and 54 of the lip seal 50.

Even if the oil-cooled screw compressor 1 of the present invention is a two-stage compressor provided with a low-pressure stage compressor main body 2 and a high-pressure stage compressor main body 3, the seal lips 53 and 54 of the shaft sealing device 5 are abnormal. It was possible to prevent wear and seizure.

Further, the oil-cooled screw compressor 1 of the present invention is a two-stage compressor, and the gear case 41 of the oil-cooled screw compressor 1 forms a part of the intermediate stage passage 19, so that the pressure inside the gear case 41 is increased. Even if the pressure becomes high, as described above, the pressure difference between the inside of the gear case 41 (inside the machine) and the seal lips 53 and 54 (refueling space 55) and the pressure difference between the refueling space 55 and the outside of the casing 41 (outside the machine). The pressure difference between the inside and outside of the machine was kept smaller, the sliding resistance of the seal lips 53 and 54 was reduced, and abnormal wear and seizure of the seal lips 53 and 54 could be prevented.

Of the plurality of seal lips provided in the shaft sealing device 5, the length of the seal lip 53 arranged on the innermost side of the machine is made shorter than the length of the other seal lips 54 to receive the pressure inside the machine. By reducing the surface area of 53, the bulging deformation of the seal lip 53 is prevented, the tightening force (pressing force) of the seal lip 53 due to the increase in the contact area between the seal lip 53 and the drive shaft 45 is suppressed, and the seal lip is suppressed. The sliding resistance of the 53 was reduced, and abnormal wear and seizure of the seal lip 53 could be prevented.

Further, since the thickness of the seal lip 53 is increased to increase the rigidity of the seal lip 53, the bulging deformation of the seal lip 53 is prevented, and the pressure difference between the machine inner space and the refueling space 55 fluctuates. However, the deformation of the seal lip 53 was reduced, the tightening force of the drive shaft 45 by the seal lip 53 was stabilized, and the sealing performance could be maintained.

Further, the pressure in the oil supply space 55 could be adjusted by providing the pressure adjusting pipe 83 with a throttle 84 having a narrow flow path area.

FIG. 5 is a cross-sectional side view showing an embodiment of the oil-cooled screw compressor of the present invention. An enlarged cross-sectional view of the shaft sealing portion 14 of FIG. The whole view which shows the refueling mechanism to the oil-cooled screw compressor of FIG. An enlarged cross-sectional view showing a modified example of the shaft sealing portion 14. An enlarged cross-sectional view showing another modified example of the shaft sealing portion 14. An enlarged cross-sectional view showing still another modified example of the shaft sealing portion 14. FIG. 5 is a cross-sectional side view showing an embodiment of a conventional oil-cooled screw compressor. FIG. 5 is a cross-sectional view showing an example of a conventional lip seal.

In the embodiment for carrying out the invention, a two-stage compression type compressor is described, but the present invention is not limited to the two-stage compression type, but is not limited to the two-stage compression type, but is limited to a single-stage compression type or a multi-stage compressor having two or more stages. As will be described later, it can be applied to a compression type and also to a compressor body without a speed-increasing device.

Hereinafter, examples of the present invention will be described with reference to the accompanying drawings, but the configuration of the present invention is not limited to the examples shown below.

The oil-cooled screw compressor 1 of the first embodiment of the present invention shown in FIG. 1 is called a so-called "two-stage compressor", and the discharge port 26 of the low-pressure stage compressor main body 2 arranged on the upper stage of the paper surface is intermediate. By communicating with the suction port 35 of the high-pressure stage compressor main body 3 arranged at the lower stage of the paper surface through the step passage 19, the compressed gas compressed by the low-pressure stage compressor main body 2 is further applied to the high-pressure stage compressor main body 3. It is configured so that it can be compressed with.

As described above, the compressor body of the present embodiment is composed of the compressor bodies 2 and 3 of the low pressure stage and the high pressure stage, and male and female in the rotor chambers 22 and 32 formed in the casings 21 and 31, respectively. A pair of screw rotors 23, 23': 33, 33'(the other rotor 23'33'in FIG. 1 is on the back surface of one rotor 23, 33) is meshed and rotatably accommodated. , Screw rotors 23, 23': 33, 33'It is possible to input the rotational driving force from a drive source (not shown) such as an engine or a motor to the rotor shafts 24, 34 of one of the screw rotors 23, 33. It is configured so that it can be done.

In order to enable such input of rotational driving force, one rotor shaft 24, 34 of each of the above-mentioned low-pressure stage and high-pressure stage compressor bodies 2 and 3 is illustrated via the speed increasing device 4. It can be connected to no drive source.

In the illustrated embodiment, the casing (gear case) 41 of the speed increasing device 4 is attached to one end side of the casings 21 and 31 of the compressor main bodies 2 and 3 of the low pressure stage and the high pressure stage, and the low pressure is formed in the gear case 41. The end portions of the rotor shafts 24 and 34 of each of the stage compressor main body 2 and the high pressure stage compressor main body 3 are inserted to attach the driven gears 42 and 43, and both of these two driven gears 42 and 43 mesh with each other. A drive gear 44 having a large diameter with respect to the driven gears 42 and 43 is accommodated, and a drive shaft 45 attached to the drive gear 44 is extended outside the gear case 41 to form a speed increasing device 4. There is.

Therefore, by inputting the rotational driving force from a driving source (not shown) such as an engine or a motor to the driving shaft 45 projecting from the gear case 41 to the outside of the machine, the rotational driving force generated by the driving source is increased. After speeding up by the speed device 4, the speed can be input to the rotor shafts 24 and 34 of the compressor main bodies 2 and 3 of the low pressure stage and the high pressure stage.

Further, in FIG. 1, the curves having arrows shown in the spaces inside the casings 21, 31, and 41 of the oil-cooled screw compressor 1 indicate the flow direction of the air flowing through the apparatus, as shown in the figure. In the compressor 1, the discharge port 26 of the low-pressure stage compressor main body 2 communicates with the suction port 35 of the high-pressure stage compressor main body 3 via the intermediate stage passage 19, and the space inside the gear case 41 is the said. It forms part of the intermediate passage 19.

Since the drive shaft 45 provided in the speed increasing device 4 extends inside and outside the gear case 41, a shaft seal portion 14 is formed at a portion where the drive shaft 45 penetrates the gear case 41 to seal the shaft. The device 5 is used to prevent the compressed fluid and lubricating oil from leaking out of the machine.

As described above, in order to provide the drive shaft 45 penetrating the inside and outside of the gear case 41, the end plate 41a of the gear case 41 is formed with a bearing chamber 11 in which the bearing 13 is housed, and the bearing chamber 11 is provided. A cover 12 is provided in the center of the gear case 41, which covers the drive shaft 45 from the shaft end direction and has a shaft hole 12d through which the drive shaft 45 can be inserted.

The bearing chamber 11 is a cylindrical space formed to a predetermined diameter, and by providing an inwardly projecting brim portion 11a on the inner peripheral edge of one end on the drive gear 44 side, the inner diameter of this portion can be changed to another. It is formed narrowly with respect to the part.

Further, the cover 12 described above has a drive shaft in the center that closes the cylindrical portion 12a inserted into the bearing chamber 11, the flange portion 12b protruding from the outer peripheral surface of the cylindrical portion 12a, and the end portion of the cylindrical portion 12a. A method such as bolting the flange portion 12b to the end plate 41a of the gear case 41 in a state where the end surface 12c in which the shaft hole 12d for inserting the 45 is formed is formed and the cylindrical portion 12a is inserted into the bearing chamber 11. By fixing the casing 41 with a shaft end, the bearing chamber 11 can be covered from the shaft end direction of the drive shaft 45.

Further, this portion is also sealed so that the fluid does not leak through the gap between the outer peripheral surface of the cylindrical portion 12a provided on the cover 12 and the inner peripheral surface of the bearing chamber 11, and is shown in the figure. In the embodiment, the gap can be sealed by inserting the cylindrical portion 12a into the bearing chamber 11 with the O-ring 15 fitted in the concave groove formed on the outer peripheral surface of the cylindrical portion 12a. I am trying to do it.

FIG. 2 is an enlarged view of the shaft sealing portion 14 of FIG. 1, and as shown in the figure, the shaft sealing device 5 used in the oil-cooled screw compressor 1 of the present embodiment has a rigid metal ring. A frame is formed by the outer case 51 and the inner case 52 of the above, and the lip seal 50 includes two seal lips 53 and 54 held by the frame and a dust strip member 56. The lip seal 50 is shown in the figure. As shown, the outer case 51 is fixed by being inserted into the inner peripheral side of the cylindrical portion 12a of the cover 12.

The seal lips 53 and 54 and the dust strip member 56 are made of synthetic resin, but it is preferable to use Teflon (registered trademark) resin (for example, ethylene tetrafluoride resin) having excellent heat resistance and abrasion resistance. ..

As shown in FIG. 2, the tips of the two seal lips 53 and 54 face the inside of the machine in the axial direction of the drive shaft 45. Here, the two seal lips 53 and 54 of the drive shaft 45 have their tips. The seal lip located inside the machine in the axial direction is called the inside seal lip 53, and the seal lip located outside the machine is called the outside seal lip 54.

As shown in FIG. 2, the dust strip member 56 is located further outside the machine than the outside seal lip 54, and the tip thereof faces the outside of the machine in the axial direction of the drive shaft 45.

In the lip seal 50, the inner peripheral surface of the machine inner seal lip 53, the machine outer seal lip 54, and the dust strip member 56 are constantly slidably contacted with the outer peripheral surface of the collar 48 fitted to the drive shaft 45 with appropriate elasticity. As a result, the inner peripheral surface of the cylindrical portion 12a of the cover 12 and the outer peripheral surface of the collar 48 are sealed, and in particular, the fluid inside the machine (inside the casing 41) is sealed by the machine inside seal lip 53 and the machine outside seal lip 54. At the same time, the dust strip member 56 prevents external dust from entering the machine.

In the present embodiment, the collar 48 is fitted to the drive shaft 45, and the two seal lips 53 and 54 and the dust strip member 56 are in sliding contact with the outer periphery of the collar 48. The two seal lips 53 and 54 and the dust strip member 56 may be in direct sliding contact with the outer peripheral surface of the drive shaft 45 without being provided.

Further, as shown in FIG. 2, in the oil-cooled screw compressor 1 of the first embodiment, the oil-cooled screw compressor 1 is provided between the machine inner seal lip 53 and the machine outer seal lip 54 by the lip seal 50. A lubrication space 55 is formed in which the lubricating oil in the oil separator (receiver tank) 88 is introduced during the operation of the oil separator (receiver tank) 88.

The refueling space 55 is a space partitioned from the inside of the gear case 41 (inside space of the machine) and the outside of the machine (atmospheric pressure) by the seal lip 53 inside the machine and the seal lip 54 outside the machine. It plays an intermediate layer between the space inside the aircraft and the outside of the aircraft (atmospheric pressure).

Further, in the lip seal 50 of the present embodiment, a spacer 6 is provided between the machine inner seal lip 53 and the machine outer seal lip 54. In the lip seal 50 of the present embodiment, the interposition of the spacer 6 between the machine inner seal lip 53 and the machine outer seal lip 54 is not essential, and the spacer 6 may be omitted.

Further, in the lip seal 50 of the present embodiment, as shown in FIG. 2, the outer case 51 and the spacer 6 are penetrated between the machine inner seal lip 53 and the machine outer seal lip 54, and a casing (in FIG. 1). , The oil supply holes 57, 61 (the oil supply holes 57 formed in the outer case 51, the oil supply holes 61 formed in the spacer 6) communicating with the oil supply passage 16 formed in the cover 12, the casing 41 and the end plate 41a). Similarly, oil drain holes 58 and 62 (oil drain holes 58 formed in the outer case 51 and oil drain holes 62 formed in the spacer 6) are formed so as to communicate with the pressure adjusting passage 18 formed in the casing.

The oil supply passage 16 communicating with the oil supply holes 57 and 61 is connected to the oil supply pipe 81, and as shown in FIG. 3, the gas-liquid mixed fluid discharged from the oil-cooled screw compressor 1 is introduced and compressed. The lubricating oil from the oil separator 88, which separates the gas and the lubricating oil and stores the separated lubricating oil, passes through the oil filter to remove impurities such as dust mixed in the lubricating oil, and the oil cooler 89 is removed. After passing through and cooling, the oil supply pipe 81 from the oil cooler 89 is branched and introduced into the oil supply passage 18 provided in the oil-cooled screw compressor main body 1, and as shown in FIG. 1, this oil supply is introduced. The passage 18 is branched, passed through the oil supply holes 57 and 61, and introduced into the oil supply space 55.

Since refueling is pressure-fed by the pressure inside the oil separator 88, lubricating oil under high pressure is introduced into the refueling space 55 between the two seal lips 53 and 54, so the space between the two seal lips 53 and 54 (refueling space). The pressure in the space of 55) becomes high, and when comparing the magnitudes of the pressure inside the gear case 41 (inside the machine), the refueling space 55, and the outside of the machine (atmospheric pressure), the pressure inside the machine> the pressure in the refueling space 55> the machine The pressure is outside (atmospheric pressure), and so on.

As a result, even if the pressure difference between the inside of the machine and the outside of the machine is large due to the high pressure inside the machine, the pressure difference between the inside of the machine and the refueling space 55 remains between the inside of the machine and the outside of the machine as described above. Since the pressure difference between the refueling space 55 and the outside of the machine is also smaller than the pressure difference between the inside and the outside of the machine, the seal lips 53 and 54 bulge and deform due to the large pressure difference. In addition to suppressing this, the force (pressing force) at which the seal lips 53 and 54 tighten the drive shaft 45 due to the pressure difference can be suppressed, and the sliding resistance can be reduced.

Further, since the machine inside seal lip 53 is lubricated by the lubricating oil transmitted from the inside of the machine along the outer circumference of the drive shaft 45 and the lubricating oil in the lubrication space 55 on the outside of the machine, the outer circumference of the collar 48 and the inside of the machine seal lip 53 are lubricated. Friction with 53 can be reduced.

Further, the pressure adjusting passage 18 communicating with the oil drain holes 58 and 62 of the lip seal 50 is connected to the pressure adjusting pipe 83, and as shown in FIG. 1, the oil supply space 55 is provided by the pressure adjusting pipe 83. It communicates with the space in the rotor chamber 22 of the low-stage compression main body 2 at a position where the pressure is relatively low with respect to the pressure in the (casing 41 accommodating the shaft sealing device 5). In FIG. 1, for convenience of drawing, a part of the path of the pressure regulating pipe 83 is omitted, and a circle symbol (circle A) is attached to the end side and the start end side thereof, and those having the same code are connected to each other. Which indicates that.

Therefore, the lubricating oil introduced into the refueling space 55 is collected in the rotor chamber 22, so that the refueling space 55 uses the refueling hole 57 to take the cooled lubricating oil from the oil separator 88 that has passed through the oil cooler 89. , 61 are sequentially introduced, and the seal lips 53 and 54 can be effectively cooled.

Further, the pressure adjusting pipe 83 of the present embodiment is provided with a throttle 84 having a narrow flow path area, and the throttle 84 is adjusted so that the refueling space 55 has an appropriate pressure. The proper pressure in the oil supply space 55 is the pressure inside the case 41 (inside the machine) and the pressure outside the machine (atmospheric pressure) when the suction valve of the oil-cooled screw compressor 1 is open. It is in the middle.

As described above, the present embodiment can prevent abnormal wear and seizure of the seal lips 53 and 54 of the lip seal 50, prevent wear of the drive shaft 45, and further, power to rotate the drive shaft. Can also be suppressed.

Regarding the lip seal 50 of the present embodiment, the length of the machine inside seal lip 53 is formed shorter than the length of the machine outside seal lip 54 to reduce the surface area of the seal lip 53 that receives the pressure inside the machine. There is. Prevents bulging deformation of the seal lip 53, suppresses the tightening force (pressing force) of the seal lip 53 due to the increase in the contact area with the drive shaft 45, reduces the sliding resistance of the seal lip 53, and reduces the sliding resistance of the seal lip 53. It is possible to prevent abnormal wear and seizure.

Further, as shown in FIG. 6a, the thickness of the shortened machine inner seal lip 53 may be made thicker than the thickness of the machine outer seal lip 54. As a result, the rigidity of the seal lip 53 is increased, the bulging deformation of the seal lip 53 is prevented, and even if the pressure difference between the machine inner space and the refueling space 55 fluctuates, the deformation of the seal lip 53 is reduced. , The tightening force of the drive shaft 45 by the seal lip 53 can be stabilized, and the seal performance can be maintained.

Further, although omitted in FIG. 2, in the oil-cooled screw compressor 1 of the present embodiment, as shown in FIG. 1, an oil drainage passage 17 is provided outside the machine in the axial direction of the drive shaft 45 from the lip seal 50. By providing the cover 12 and communicating the oil drainage passage 17 with the drain pipe 85, the lubricating oil leaked beyond the lip seal 50 is collected in the drain receiver 86 via the oil drainage passage 17 and the drain pipe 85. May be possible.

The oil-cooled screw compressor 1 of the second embodiment of the present invention has the same structure as that of the first embodiment described above except for the structure of the shaft sealing device 5 in the shaft sealing portion 14.

The shaft sealing device 5 of the first embodiment described above is a lip seal 50 in which two seal lips 53 and 54 are integrally formed on one lip seal, but the shaft sealing device 5 of the second embodiment is As shown in FIG. 4, No. 5 is composed of two lip seals having one seal lip on one lip seal, and the first lip seal located inside the machine in the axial direction of the drive shaft 45 (1). The lip seal (inside the machine) is called the lip seal 50a, and the lip seal located on the outside of the machine is called the second (outside the machine) lip seal 50b.

Each of the first lip seal 50a and the second lip seal 50b has a frame formed by the outer cases 51a and 51b and the inner cases 52a and 52b having a rigid metal ring, and the seal member (seal lip) 53a held by the frame. , 53b, and further, the second lip seal 50b is provided with a dust strip member 56a on the outer side of the seal member 53b.

Further, as shown in FIG. 4, the first lip seal 50a and the second lip seal 50b are fixed by inserting the outer cases 51a and 51b into the inner peripheral side of the cylindrical portion 12a of the cover 12, respectively. An oil supply space 55a is formed between the 1 lip seal 50a and the 2nd lip seal 50b, and a spacer 6 is provided between the seal members 53a and 53b of the two lip seals.

Further, as shown in FIG. 4, the spacer 6 is provided with an oil supply hole 61 and an oil drain hole 62, and the oil supply hole 61 is provided with an oil supply pipe 81 (FIG. 4) via the oil supply passage 16 as in the first embodiment described above. The oil drain hole 62 communicates with the pressure adjusting pipe 83 (not shown) via the pressure adjusting passage 18.

As shown in FIG. 4, in the present embodiment, since the refueling passage 16 communicates with the refueling space 55a formed between the two lip seals 50a and 50b, the lip seal is different from the first embodiment. It is not necessary to directly form the oil supply hole and the oil drain hole.

With the above configuration, high pressure lubricating oil is introduced from the oil separator 88 into the oil supply space 55a between the two sealing members 53a and 53b, so that the pressure in the oil supply space 55a becomes high and the pressure in the space of the oil supply space 55a becomes high, and the pressure in the gear case 41 (machine). Comparing the magnitudes of the pressure inside the machine, the refueling space 55a, and the pressure outside the machine (atmospheric pressure), the pressure inside the machine> the pressure inside the refueling space 55a> the pressure outside the machine (atmospheric pressure), in that order. Even if the pressure difference between the inside of the machine and the outside (atmospheric pressure) is large due to the high pressure inside the machine, the pressure difference between the inside of the machine and the refueling space 55a is inside the machine. The pressure difference between the inside and outside of the machine (atmospheric pressure) is small, and the pressure difference between the refueling space 55a and the outside of the machine is also small compared to the pressure difference between the inside of the machine and the outside of the machine (atmospheric pressure). It is possible to prevent the seal members 53a and 53b from bulging and deforming due to the difference, and to suppress the force (pressing force) at which the seal members 53a and 53b tighten the drive shaft 45 due to the pressure difference, thereby reducing the sliding resistance.

Further, since the lubricating oil introduced into the oil supply space 55a is collected in the rotor chamber 22 via the pressure adjusting pipe 83, the oil supply space 55a is cooled lubrication from the oil separator 88 that has passed through the oil cooler 89. Since the oil is sequentially introduced through the oil supply holes 61, the seal members 53a and 53b can be effectively cooled.

Further, in the present embodiment, the length of the seal member 53a of the first lip seal 50a is shorter than the length of the seal member 53b of the second lip seal 50b.

Further, in the lip seal of the present embodiment, as shown in FIG. 6b, the thickness of the seal member 53a of the first lip seal 50a may be thicker than the thickness of the seal member 53b of the second lip seal 50b.

The oil-cooled screw compressor 1 of the third embodiment of the present invention is the first except for the structure of the shaft sealing device 5, the oil supply passage 16, the pressure adjusting passage 18, and the pressure adjusting pipe 83 in the shaft sealing portion 14. It has the same structure as the embodiment.

As shown in FIG. 5, the shaft sealing device 5 of the third embodiment is composed of three lip seals having one seal lip on one lip seal, and here, the most machine in the axial direction of the drive shaft 45. The lip seal arranged inside is called the first lip seal 50a', the lip seal arranged in the center is called the second lip seal 50b', and the lip seal arranged on the outermost side of the machine is called the third lip seal 50c'.

Each of the first to third lip seals 50a', 50b', and 50c'is framed by the outer cases 51a', 51b', 51c'and the inner cases 52a', 52b', 52c', which are rigid metal rings. A seal member (seal lip) 53a', 53b', 53c'held in the frame is provided, and a third lip seal 50c'is a dust strip on the outside of the seal member 53c'. A member 56a'is provided.

Further, the length of the seal member 53a'of the first lip seal 50a'is made shorter than the length of the seal member 53b' of the second lip seal 50b', and the length of the seal member 53b' of the second lip seal 50b'is shortened. The length of the third lip seal 50c'is shorter than the length of the seal member 53c'.

Further, in the first to third lip seals 50a', 50b', 50c', as shown in FIG. 5, the outer cases 51a', 51b', 51c' are placed on the inner peripheral side of the cylindrical portion 12a of the cover 12. Each is fixed by inserting, and the first refueling space 55a'is provided between the first lip seal 50a'and the second lip seal 50b', and the second lip seal 50b'and the third lip seal 50c' A second refueling space 55b'is formed between them, and between the first lip seal 50a'and the second lip seal 50b', and between the second lip seal 50b'and the third lip seal 50c'. Spacers 6 and 6'are provided for each.

Refueling holes 61, 61'and drain holes 62, 62'are provided in the spacers 6, 6', respectively, and the oil supply holes 61, 61'communicate with the oil supply pipe 81 via the oil supply passages 16a and 16b to drain oil. The holes 62 and 62'communicate with the pressure adjusting pipe 83 via the pressure adjusting passages 18a and 18b.

As shown in the figure, the refueling passages 16a and 16b communicate with each other in the space (refueling space) formed between the three lip reels 50a', 50b', and 50c'. Unlike, it is not necessary to form oil supply holes and oil drain holes directly on the lip seal.

As shown in FIG. 5, the refueling passage 16 of the present embodiment has a first refueling passage 16a corresponding to the refueling hole 61 opened in the spacer 6 between the first lip seal 50a'and the second lip seal 50b'. , The second refueling passage 16b corresponding to the refueling hole 61'opened in the spacer 6'between the second lip seal 50b'and the third lip seal 50c'.

Further, the pressure adjusting passage 18 of the present embodiment is the first pressure adjusting passage 18a corresponding to the oil drain hole 62 opened in the spacer 6'provided between the first lip seal 50a'and the second lip seal 50b'. And a second pressure adjusting passage 18b corresponding to the oil drain hole 62'opened in the spacer 6'provided between the second lip seal 50b'and the third lip seal 50c' are provided.

Further, in the present embodiment, the first pressure adjusting pipe 83a connected to the first pressure adjusting passage 18a and the second pressure adjusting pipe 83b connected to the second pressure adjusting passage 18b are provided with throttles 84a and 84b, respectively. The first throttle 84a provided in the first pressure adjusting pipe 18a is formed thinner than the second throttle 84b provided in the second pressure adjusting pipe 18b, and the other ends of the first pressure adjusting pipe and the second pressure adjusting pipe are respectively formed. , It is connected to the space in the rotor chamber 22 of the low pressure stage compressor main body 2 at a position relatively low with respect to the pressure in the casing 41 accommodating the shaft sealing device 5.

In the present embodiment, due to pressure feeding from the oil separator 88, the lubricating oil under high pressure is first between the sealing member 53a'of the first lip seal 50a'and the sealing member 53b' of the second lip seal 50b'. The oil supply space 55a'and the second oil supply space 55b'between the seal member 53b'of the second lip seal 50b'and the seal member 53c' of the third lip seal 50c', and described above. The pressure in each of the oil supply spaces 55a'and 55b'in the full load state where the suction valve of the oil-cooled screw compressor 1 is open is stepped from the inside of the gear case 41 to the outside of the machine by the first throttle 84a and the second throttle 84b. When the pressure inside the gear case 41 (inside the machine space), the first oil supply space 55a', the second oil supply space 55b', and the outside of the machine (atmospheric pressure) are compared, the pressure inside the machine is compared. Pressure> Pressure in the first refueling space 55a'(inside refueling space)> Pressure in the second refueling space 55b' (outside refueling space)> Pressure outside the machine (atmospheric pressure).

As a result, even when the pressure difference between the inside of the machine and the outside of the machine (atmospheric pressure) is large due to the high pressure inside the gear case 41 (inside the machine), the inside of the machine and the inside of the first refueling space 55a' The pressure difference is smaller than the pressure difference between the inside and outside of the machine. Similarly, the pressure difference between the first refueling space 55a'and the second refueling space 55b', and the second refueling space 55b'and the outside of the machine. Since the pressure difference between the above and the outside of the machine (atmospheric pressure) is smaller than the pressure difference between the inside and outside of the machine (atmospheric pressure), the seal members 53a', 53b', and 53c' are suppressed from bulging and deforming due to the large pressure difference, and the pressure Due to the difference, the sealing members 53a', 53b', 53c' can suppress the force (pressing force) for tightening the drive shaft 45, and the sliding resistance can be reduced.

Further, since the lubricating oil introduced into the refueling spaces 55a'and 55b' is collected in the rotor chamber 22 via the pressure adjusting pipe 83, the first refueling space 55a'and the second refueling space 55b'are collected. The cooled lubricating oil from the oil separator 88 that has passed through the oil cooler 89 is sequentially introduced through the oil supply holes 61, and the sealing members 53a', 53b', and 53c'can be effectively cooled.

Further, in the present embodiment, the pressure in each of the refueling spaces 55a'and 55b' is adjusted by the diameter (thinness) of the first throttle 84a and the second throttle 84b, but the pressure in each refueling space is stepwise. In addition to adjusting the diameter of the throttle so that it is as low as possible, the other end of the first pressure regulating pipe 83a should communicate with the working space at a higher pressure than the working space of the rotor chamber with which the second pressure adjusting pipe 84b communicates. It may be.

Although the embodiment of the present invention has been described above, in order to form at least one of the refueling spaces 55, the number of lip seals having one seal lip is two or more, and the number of lip seals having two or more seal lips is one. That is all.

For example, in the first embodiment, as shown in FIG. 2, one lip seal having the seal lip of 2 is installed. In the second embodiment, as shown in FIG. 4, two lip seals each having one seal lip are installed. In the third embodiment, as shown in FIG. 5, three lip seals each having one seal lip are installed.

All of the above-described embodiments have been described by taking as an example a case where a lip seal is provided on the shaft sealing portion 14 of the two-stage screw compressor provided with the speed increasing device 4. The oil-cooled screw compressor 1 of the present invention is not limited to the two-stage screw compressor, and for example, a lip seal is provided on the shaft seal portion 14 of the speed increasing device 4 provided in the single-stage compressor main body 2'. It may be one, or it does not have a speed-up device as in the case where one of the rotor shafts directly penetrates the casing and protrudes to the outside of the machine to serve as a drive shaft that communicates with the drive source. A lip seal may be used for the shaft seal of the compressor body.

1 Oil-cooled screw compressor 11 Bearing chamber 11a Brim 12 Cover 12a Cylindrical 12b Flange 12c End face 12d Shaft hole 13 Bearing 14 Shaft seal 15 O-ring 16 Refueling passage 16a 1st refueling passage 16b 2nd refueling passage 17 Oil passage 18 Pressure regulation passage 18a 1st pressure adjustment passage 18b 2nd pressure adjustment passage 19 Intermediate stage passage 2 Low pressure stage compressor body (2'compressor body (single stage type))
21 Casing 22 Rotor chamber 23,23'Screw rotor 24 Rotor shaft 25 Suction port 26 Discharge port 3 High-pressure stage compressor body 31 Casing 32 Rotor chamber 33, 33'Screw rotor 34 Rotor shaft 35 Suction port 36 Discharge port 4 Accelerator 41 Gear case (casing)
41a End plate (of gear case)
42, 43 Driven gear 44 Drive gear 44a Boss (of drive gear)
45 Drive shaft 48 color 5 shaft sealing device 50 Lip seal 50a 1st lip seal 50b 2nd lip seal 50a'1st lip seal 50b' 2nd lip seal 50c' 3rd lip seal 51 Outer case 51a, 51b Outer case 51a' , 51b', 51c'Outer case 52 Inner case 52a, 52b Inner case 52a', 52b', 52c' Inner case 53 (inside the machine) Seal lip 53a, 53b Seal member 53a', 53b', 53c' Seal member 54 ( Outside the machine) Seal lip 55 Refueling space 55a Refueling space
55a'First refueling space 55b' Second refueling space 56 Dustrip member 56a Dust strip member 56a'Dust strip member 57 Refueling hole 58 Drainage hole 6,6'Spacer 61,61' Refueling hole 62,62' Drainage Oil hole 81 Refueling pipe 83 Pressure adjusting pipe 83a First pressure adjusting pipe 83b Second pressure adjusting pipe 84 Squeezing 84a First squeezing 84b Second squeezing 85 Drain pipe 86 Drain receiver 88 Oil separator (receiver tank)
89 Oil cooler 200 Oil-cooled screw compressor 214 Shaft seal 212 Mechanical seal 220 Low-pressure stage compressor body 221 Casing 222 Rotor chamber 223, 223'Screw rotor 224 Rotor shaft 225 Suction port 226 Discharge port 230 High-pressure stage compressor body 231 Casing 232 Rotor chamber 233, 233'Screw rotor 234 Rotor shaft 235 Suction port 236 Discharge port 240 Speed increasing device 241 Gear case (casing)
241a End plate (of gear case)
242,243 Driven gear 244 Drive gear 245 Drive shaft 250 Intermediate stage passage 300 Lip seal 301 Lip holding part 302 Seal lip 303 Metal ring 320 Drive shaft 330 Casing

Claims (8)

A pair of male and female screw rotors are rotatably housed in a rotor chamber formed in a casing, and the compressed gas is sucked into the rotor chamber by the meshing rotation of both screw rotors, and is compressed together with lubricating oil in the rotor chamber. The compressor body that compresses the gas and discharges the gas-liquid mixed fluid of the compressed gas and the lubricating oil, and the gas-liquid mixed fluid discharged from the compressor body are introduced and separated into the compressed gas and the lubricating oil. An oil separator that stores the separated lubricating oil, an oil cooler that cools the lubricating oil stored in the oil separator, and a refueling pipe that supplies the lubricating oil cooled by the oil cooler to each part of the compressor body. A drive shaft is inserted into the compressor body by opening a shaft hole in the wall surface of the casing to connect to the drive source, and at a relatively high pressure between the shaft hole and the outer periphery of the drive shaft. An oil-cooled screw compressor equipped with a shaft seal device that prevents fluid inside a machine from leaking to the outside of the machine, which has a relatively low pressure.
The shaft sealing device is formed between the adjacent seal lips, with the tip end in the machine-inside direction in the axial direction of the drive shaft, and at least two seal lips that are in sliding contact with the outer periphery of the drive shaft at intervals. A lip seal having the seal lip is provided so as to have at least one refueling space partitioned from the outside.
The lubricating oil storage portion of the oil separator and the refueling space are communicated with each other via the refueling pipe, and at the same time.
Among the rotor chamber of the compressor body, and a relatively low pressure space with respect to the pressure space in the casing provided with the shaft sealing device, it is communicated through the oil supply space and is regulated pressure line An oil-cooled screw compressor characterized in that the pressure in the refueling space is adjusted to a low pressure with respect to the pressure inside the machine and a high pressure with respect to the pressure outside the machine. The oil-cooled screw compressor according to claim 1, wherein the shaft sealing device includes a lip seal in which two or more seal lips are integrally formed. The oil-cooled screw compressor according to claim 1, wherein the shaft sealing device includes two or more lip seals including one seal lip. The compressor main body is provided with an intermediate stage passage that communicates the low pressure stage compressor main body and the high pressure stage compressor main body with the discharge port of the low pressure stage compressor main body and the suction port of the high pressure stage compressor main body.
The refueling pipe communicates the lubricating oil storage portion of the oil separator with the refueling location of the low pressure stage compressor main body, the refueling location of the high pressure stage compressor main body, and the refueling space of the shaft sealing device. ，
The oil-cooled screw according to any one of claims 1 to 3, wherein the pressure adjusting pipe communicates the oil supply space of the shaft sealing device with the rotor chamber of the low-pressure stage compressor main body. Compressor. The compressor main body accommodates a speed-increasing gear that accelerates the rotation of the drive shaft connected to the drive source and transmits the low-pressure stage compressor main body and the high-pressure stage compressor main body in a gear case, and the low-pressure stage compressor main body. The discharge port of the compressor body and the suction port of the high-pressure stage compressor body are connected to the space inside the gear case, and the gear case forms a part of the casing and the intermediate stage passage, and is shafted on the wall surface of the gear case. The oil-cooled screw compressor according to claim 4, wherein a hole is opened to insert the drive shaft, and the shaft sealing device is provided between the shaft hole and the outer periphery of the drive shaft. Among the plurality of seal lips provided in the shaft sealing device, the length of the seal lip arranged on the innermost side of the machine in the axial direction of the drive shaft is formed to be shorter than the length of the other seal lips. The oil-cooled screw compressor according to any one of claims 1 to 5. Among the plurality of seal lips provided in the shaft sealing device, the thickness of the seal lip arranged on the innermost side of the machine in the axial direction of the drive shaft is made thicker than the thickness of the other seal lips. The oil-cooled screw compressor according to claims 1 to 6. The oil-cooled screw compressor according to any one of claims 1 to 7, wherein the pressure adjusting pipe is provided with a throttle having a narrow flow path area.

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