JP4717048B2 - Screw compressor - Google Patents

Description

  The present invention relates to a screw compressor.

  In a screw compressor that compresses air with a pair of male and female screw rotors, lubricating oil is injected into the rotor chamber for lubrication and sealing between the screw rotors and between the screw rotor and the rotor chamber, or for cooling the screw rotor and the like. Things are common. In a screw compressor using such lubricating oil, the lubricating oil is separated from the discharged compressed air by an oil separator, and the separated lubricating oil is injected again into the rotor chamber. Lubricating oil is also injected into the bearing chamber that houses the bearing that supports the shaft of the screw rotor, lubricates the bearing, and the lubricating oil overflowing from the bearing chamber is recovered and injected again into the rotor chamber or bearing chamber. . Since the heat generated in the rotor chamber and the bearing increases the temperature of lubrication, there are many screw compressors equipped with an oil cooler that cools the recovered lubricating oil.

  In such an oil-cooled screw compressor, the lubricating oil is separated from the discharged compressed air by an oil separator, but it is difficult to completely remove the oil from the compressed air. Therefore, a screw compressor that lubricates the screw rotor with oil cannot be used in food factories, chemical factories, precision instrument factories, etc. that require clean compressed air that does not contain oil. Therefore, a screw compressor has been proposed in which water is supplied to the rotor chamber and the screw rotor is lubricated, sealed and cooled with water.

  However, since water has a low viscosity, it is difficult to directly mesh the screw rotors. For this reason, in the screw compressor which lubricates a metal screw rotor with water, it is necessary to provide the synchronizing gear which meshes | engages mutually and synchronizes screw rotors at the edge part of a rotor shaft. In the screw compressor, it is necessary to lubricate the synchronous gear, the rotor shaft bearing, and the gear that transmits the rotational force of the motor to the rotor shaft, but it is difficult to sufficiently lubricate these with water.

  If a slide bearing is adopted as a screw rotor bearing, the bearing can be lubricated even with water. However, since the slide bearing has a large gap, the alignment accuracy is low, and the friction is large. Therefore, the slide bearing has a disadvantage that its life is short due to wear, and the use of a rolling bearing is desired.

  Further, by using a resin screw rotor, the screw rotors can be directly meshed with each other even with water lubrication. However, resin screw rotors have a larger coefficient of linear expansion than metal screw rotors, and there is a concern that they will absorb moisture over time, so that the clearance must be increased and the performance is inferior. There is a problem.

As described above, even in a water-lubricated screw compressor, it is desirable to lubricate bearings and gears with lubricating oil. Therefore, in a water-lubricated screw compressor, lubricating oil is sealed in a bearing chamber that houses the bearing and gear, and an oil reservoir is formed so that a part of the bearing and gear is immersed. However, the heat generated by the friction of the bearings and gears increases the temperature of the lubricating oil, causing a problem of poor lubrication and reducing the life of the lubricating oil. In addition, if ancillary equipment is provided to circulate and cool the lubricating oil only for lubricating the bearings and gears to the outside of the compressor, the cost burden becomes excessive.
JP-A-10-141262 JP 2002-310079 A Japanese Patent No. 2580020

  In view of the above-described problems, an object of the present invention is to provide a screw compressor that can cool a lubricating oil for a bearing of a screw compressor, particularly a screw compressor that lubricates a screw rotor with water.

In order to solve the above problems, a screw compressor according to the present invention accommodates a pair of male and female screw rotors that mesh with each other, holds a rotor chamber to which cooling water is supplied, and a bearing that supports the rotor shaft of the screw rotor. And a bearing chamber having an oil reservoir for storing lubricating oil, supplying the cooling water to the rotor chamber through a cooling pipe penetrating the oil reservoir, and at least one of the screw rotors The rotor shaft has a gear in the bearing chamber, the gear is at least partially immersed in the oil reservoir, and the oil reservoir has an outer shape immediately below at least a portion of the gear immersed in the lubricating oil. Is formed in a cylindrical shape slightly larger than the outer periphery of the gear.

According to this configuration, the bearing lubricating oil can be cooled by exchanging heat with the cooling water for cooling the screw rotor via the cooling pipe inside the screw compressor. In addition, since this configuration is simple and the cost increases slightly, cooling of the lubricating oil prevents lubrication failure, prolongs the life of the lubricating oil and the bearing, and enables high-speed operation of the screw compressor.

According to the above configuration, since the gear is at least partially immersed in the oil reservoir , not only the bearing but also the gear can be lubricated and cooled by the lubricating oil.

Further , according to the above configuration, the outer shape of the oil reservoir immediately below the portion of the gear immersed in the lubricating oil is formed in a cylindrical shape slightly larger than the outer periphery of the gear. Since the amount of lubricating oil to be stirred is reduced and heat generation is reduced, the temperature of the lubricating oil can be kept low.

  In the screw compressor according to the present invention, the gear may be a connection gear to which a rotational force from a driving source is transmitted, and is provided on both of the rotor shafts and meshes with each other to synchronize the rotor shaft. And a synchronous gear that is rotated.

  According to this configuration, the gear for driving and synchronizing the screw rotor can be lubricated and cooled.

  In the screw compressor of the present invention, the diameter of the cooling pipe that penetrates the oil reservoir in which the connection gear is immersed is larger than the diameter of the cooling pipe that penetrates the oil reservoir in which the synchronous gear is immersed. May be.

  According to this configuration, since the heat transfer area between the lubricating oil and the cooling fluid of the connecting gear is larger than the heat transfer area between the lubricating oil and the cooling fluid of the synchronous gear, the transmission torque is larger than that of the synchronous gear, and the amount of generated heat is reduced. Large connecting gear lubricant can be cooled sufficiently.

  In the screw compressor of the present invention, the cooling pipe that penetrates the oil reservoir in which the connection gear is immersed and the cooling pipe that penetrates the oil reservoir in which the synchronous gear is immersed are connected in parallel. May be.

  According to this configuration, the flow rate of the cooling fluid flowing through the cooling pipe penetrating the oil sump in which the connecting gear is immersed and the flow rate of the cooling fluid flowing in the cooling pipe penetrating the oil sump in which the synchronous gear is immersed are calculated as the pipe diameter. The difference in cooling effect can be freely set.

  Moreover, the screw compressor of this invention WHEREIN: The said cooling piping may consist of copper pipes.

  According to this configuration, the lubricating oil can be efficiently cooled by the copper pipe having high thermal conductivity.

  In the screw compressor of the present invention, cooling fins may be provided outside the casing forming the bearing chamber.

  According to this configuration, in addition to heat exchange with the cooling fluid, the heat of the lubricating oil can be released to the outside air through the casing.

  According to the present invention, the lubricating oil can be cooled by a simple configuration in which the cooling pipe penetrating the oil reservoir of the lubricating oil in the bearing of the rotor shaft is provided. This prevents poor lubrication, extends the life of the lubricating oil and the bearing, and enables high-speed operation of the screw compressor.

Embodiments of the present invention will now be described with reference to the drawings.
1 and 2 show a screw compressor 1 according to a first embodiment of the present invention. In the screw compressor 1, a pair of male and female screw rotors (male rotor and female rotor) 4 and 5 that mesh with each other are rotatably accommodated in a rotor chamber 3 formed in a housing 2.

  As the screw rotors 4 and 5 rotate, the air is sucked and compressed from the suction port 6 communicating with the rotor chamber 3 formed in the housing 2, and the compressed air is discharged from the discharge port 7.

  The rotor shafts 8 and 9 of the screw rotors 4 and 5 are rotatably supported by rolling bearings 12 and 13 held in bearing chambers 10 and 11 formed on both sides of the rotor chamber 3, respectively. The rotor chamber 3 and the bearing chambers 10 and 11 are separated by seal members 14 and 15. The suction-side bearing chamber 10 is sealed by a flange 17 of the motor 16, and the discharge-side bearing chamber 11 is sealed by a cover 18.

  A connecting gear 19 is provided at the suction side end of the rotor shaft 8 of the male rotor 4. The connection gear 19 is engaged with a drive gear 21 provided on the motor shaft 20 protruding into the bearing chamber 10 from the flange 17 of the motor 16, and transmits the rotational force of the motor 16 to the rotor shaft 8.

  Synchronous gears 22 and 23 that mesh with each other are provided at the discharge side ends of the rotor shafts 8 and 9. The synchronous gears 22 and 23 synchronize the rotation of the rotor shafts 8 and 9 and rotate the screw rotors 4 and 5 so as not to contact each other while maintaining a clearance.

  As shown in FIG. 2, the bearing chambers 10 and 11 are filled with lubricating oil for lubricating the bearings 12 and 13, respectively. The enclosed lubricating oil is stored below the bearing chambers 10 and 11 to form oil reservoirs 24 and 25, respectively. The oil reservoirs 24 and 25 have a liquid level that immerses at least a part of the bearings 12 and 13, the connection gear 19, and the synchronous gears 22 and 23.

  As shown in FIGS. 3 and 4, the screw compressor 1 penetrates the housing 2 from the outside to the inside and further from the inside to the outside so as to penetrate the oil reservoir 24 of the bearing chamber 10 on the suction side. The cooling pipe 26 made of a copper pipe and the cooling pipe 27 made of a copper pipe that penetrates the cover 18 from the outside to the inside and further from the inside to the outside so as to penetrate the oil reservoir 25 of the bearing chamber 11 on the discharge side. And have. The cooling pipes 26 and 27 are airtightly attached to the housing 2 and the cover 18 by a bore through type joint 28 used for installation of a thermocouple or the like.

  As shown in FIG. 1, cooling water (cooling fluid) is supplied from the water cooler 29 to the cooling pipe 26 that penetrates the suction-side bearing chamber 10, and the cooling pipe 26 that penetrates the oil reservoir 24 of the bearing chamber 10. The cooling water that has flowed therethrough further flows through the cooling pipe 27 that passes through the oil reservoir 25 of the bearing chamber 11 on the discharge side, and is supplied to the rotor chamber 3. The cooling water supplied to the rotor chamber 3 cools the rotor chamber 3 and the screw rotors 4, 5, and between the screw rotors 4, 5 and between the screw rotors 4, 5 and the inner wall of the rotor chamber 3. Seal. The cooling water supplied to the rotor chamber 3 is discharged from the discharge port 7 together with the compressed air, separated from the compressed air in the gas-liquid separator 30 and circulated to the water cooler 29.

  In the screw compressor 1, the lubricating oil enclosed in the bearing chambers 10 and 11 is caused by rolling friction of the bearings 12 and 13, friction between the connection gear 19 and the drive gear 21, heat generation due to friction between the synchronous gears 22 and 23, and The temperature rises due to heat generated by stirring the lubricating oil. However, since the cooling water flowing through the cooling pipes 26 and 27 exchanges heat with the lubricating oil via the cooling pipes 26 and 27 and takes the heat of the lubricating oil, the temperature of the lubricating oil is prevented from rising excessively. .

  Thus, in the screw compressor 1, since the cooling pipes 26 and 27 are provided, overheating of the lubricating oil is prevented, so that the bearings 12 and 13 and the gears 18, 21, 22, and 23 are seized due to poor lubrication. The screw rotors 4 and 5 can be rotated at a high speed to increase the compression capacity. Further, the deterioration of the lubricating oil can be prevented by preventing overheating of the lubricating oil, and the maintenance cost of the screw compressor 1 can be reduced.

  5 and 6 show a screw compressor 1 according to a second embodiment of the present invention. In the following description, the same components as those described above are denoted by the same reference numerals, and description thereof is omitted. In the screw compressor 1 of this embodiment, the diameter of the cooling pipe 26 that penetrates the oil sump 24 of the bearing chamber 10 that houses the connection gear 19 passes through the oil sump 25 of the bearing chamber 11 that accommodates the synchronous gears 22 and 23. The diameter of the cooling pipe 27 is larger.

  The connecting gear 19 transmits all the torque output from the motor 16 to the rotor shaft 8 of the male rotor 4, while the synchronous gears 22 and 23 transmit a part of the torque of the motor 16 to the rotor shaft 9 of the female rotor 5, This is only for synchronization between the rotor shafts 8 and 9. Therefore, the heat generation amount of the connection gear 19 and the drive gear 21 is larger than the heat generation amount of the synchronous gears 22 and 23. In the present embodiment, the heat transfer areas of the cooling pipes 26, 27 and the oil reservoirs 24, 25 are made different according to the amount of heat generated in the bearing chambers 10, 11, and the temperature of the oil reservoir 24 and the temperature of the oil reservoir 25 are Can be cooled to substantially the same temperature. As the diameter of the cooling pipes 26 and 27 increases, the flow rate of the cooling water in the cooling pipes 26 and 27 decreases. However, an increase in cooling efficiency due to an increase in heat transfer area results in a decrease in cooling efficiency due to a decrease in flow rate. Win.

  Furthermore, in FIG. 7, the screw compressor 1 of 3rd Embodiment of this invention is shown. In the screw compressor 1 of the present embodiment, not only the diameter of the cooling pipe 26 that penetrates the bearing chamber 10 is larger than the diameter of the cooling pipe 27 that penetrates the bearing chamber 11, but the cooling pipe 26 and the cooling pipe 27 are arranged in parallel. It is connected. That is, the cooling water supplied from the cooler 29 is branched immediately before and supplied to the cooling pipe 26 and the cooling pipe 27. The cooling water flowing through the cooling pipes 26 and 27 merges and is introduced into the rotor chamber 3. Is done.

  In the present embodiment, the flow rate of the cooling water in the cooling pipe 26 does not become slower than the flow rate of the cooling water in the cooling pipe 27. Moreover, the ratio of the flow rate of the cooling water between the cooling pipe 26 and the cooling pipe 27 can be freely set using an orifice or the like. Therefore, even when the heat generation amount of the connection gear 19 and the drive gear 21 is considerably larger than the heat generation amount of the synchronous gears 22 and 23, the ratio between the cooling capacity of the oil reservoir 24 and the cooling capacity of the oil reservoir 25 is Can be set appropriately.

  Furthermore, in FIG. 8, the screw compressor 1 of 4th Embodiment of this invention is shown. In the screw compressor 1 of the present embodiment, cooling fins 31 are formed so as to protrude outside the housing 2 that forms the bearing chamber 10 and the cover 18 that seals the bearing chamber 11. In the present embodiment, the cooling fin 31 can also dissipate the heat of the lubricating oil to the outside air, so that the effect of cooling the lubricating oil sealed in the bearing chamber 10 and the bearing chamber 11 is higher.

  Furthermore, in FIG. 9, the screw compressor 1 of 5th Embodiment of this invention is shown. In the screw compressor 1 of the present embodiment, the housing 2 that forms the bearing chamber 10 and the cover 18 that seals the bearing chamber 11, as in the bearing chamber 11 shown in FIG. A portion defining the outer shape of the oil reservoir immediately below the gears 22 and 23 is formed in a cylindrical shape slightly larger than the outer periphery of the connection gear 19 and the synchronous gears 22 and 23. That is, the housing 2 and the cover 18 have cross-sectional shapes perpendicular to the rotor shafts 8 and 9 at the portions that define the outer shapes of the oil reservoirs 24 and 25, respectively, than the outer shapes of the gears 19, 22, and 23. It is formed so as to be an arc having a slightly larger diameter. As a result, the amount of lubricating oil directly agitated by the connecting gear 19 and the synchronous gears 22 and 23 decreases, and the amount of heat generated by the lubricating oil decreases.

  In the above embodiment, copper pipes are used for the cooling pipes 26 and 27. However, since the copper pipe not only has a high thermal conductivity, but can be easily piped by an inexpensive commercially available pipe joint, Contributes to reduction.

The horizontal sectional view of the screw compressor of a 1st embodiment of the present invention. FIG. 2 is a vertical sectional view of the screw compressor of FIG. 1. Sectional drawing of the bearing chamber of the suction side of the screw compressor of FIG. Sectional drawing of the bearing chamber of the discharge side of the screw compressor of FIG. The horizontal sectional view of the screw compressor of a 2nd embodiment of the present invention. FIG. 2 is a vertical sectional view of the screw compressor of FIG. 1. The horizontal sectional view of the screw compressor of a 3rd embodiment of the present invention. The horizontal sectional view of the screw compressor of a 4th embodiment of the present invention. The vertical sectional view of the screw compressor of a 5th embodiment of the present invention. FIG. 10 is a cross-sectional view of the bearing chamber on the discharge side of the screw compressor of FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw compressor 2 Housing 3 Rotor chamber 4 Screw rotor (male rotor)
5 Screw rotor (female rotor)
8, 9 Rotor shaft 10, 11 Bearing chamber 12, 13 Bearing 19 Connection gear 21 Drive gear 22, 23 Synchronous gear 24, 25 Oil reservoir 26, 27 Cooling pipe 31 Radiation fin

Claims (8)

A rotor chamber containing a pair of male and female screw rotors that mesh with each other, and supplied with cooling water;
Holding a bearing that supports the rotor shaft of the screw rotor, and having a bearing chamber provided with an oil reservoir for storing lubricating oil;
Through the cooling pipe provided through the oil reservoir, the cooling water is supplied to the rotor chamber ,
The rotor shaft of at least one of the screw rotors has a gear in the bearing chamber,
The gear is at least partially immersed in the oil sump;
A screw compressor , wherein the oil reservoir is formed in a cylindrical shape in which an outer shape directly below at least a portion of the gear immersed in the lubricating oil is slightly larger than an outer periphery of the gear . The screw compressor according to claim 1 , wherein the gear is a connection gear to which a rotational force from a driving source is transmitted. 2. The screw compressor according to claim 1 , wherein the gear is a synchronous gear that is provided on both of the rotor shafts and meshes with each other to rotate the rotor shaft synchronously. The gear is provided at an end of the rotor shaft opposite to the connection gear, to which the rotational force from the driving source is transmitted, and meshes with each other to rotate the rotor shaft synchronously. The screw compressor according to claim 1 , further comprising a synchronous gear. Diameter of the cooling pipe where the connection gear penetrates the reservoir the oil immersed is claimed in claim 4, wherein the synchronization gears being greater than the diameter of the cooling pipe that penetrates the reservoir the oil immersed Screw compressor. And the cooling pipe where the connection gear penetrates the reservoir the oil soaked, the synchronization claim 4 or 5 gear, characterized in that the said cooling pipe extending through the sump the oil is soaked connected in parallel Screw compressor described in 1. The screw compressor according to any one of claims 1 to 6 , wherein the cooling pipe is made of a copper pipe. The screw compressor according to any one of claims 1 to 7 , wherein a cooling fin is provided outside a casing forming the bearing chamber.

Images