TWI611106B - Screw compressor - Google Patents

Description

Screw compressor

The present invention relates to a screw compressor, and more particularly to a screw compressor having a cooling structure for cooling a motor in which a spiral rotor is rotationally driven.

The screw compressor is a pair of male and female spiral rotors that are rotationally driven by a motor. When the motor is driven at high speed, the motor is caused by the so-called iron loss (hysteresis loss or eddy-current loss) or copper loss (loss caused by coil resistance). heat. Therefore, a cooling jacket that cools a heat generating motor is provided on the outer peripheral portion of the motor casing, and the motor is cooled by heat exchange with a cooling medium such as cooling water or a coolant flowing through the cooling jacket (refer to Patent Document 1). ).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2000-97186

Generally, when the output of the motor is P (W), the number of revolutions of the motor is N (rpm), and the torque generated by the motor is T (N‧ m), the output P (W) of the motor is P ( W) = (2π / 60) × N (rpm) × T (N‧ m) relational expression. When the output P of the motor is the same, when the number of revolutions N is large and the rotation is performed at a high speed, the torque T becomes small, and the size of the motor can be reduced. A high-speed motor using a high-frequency inverter is, for example, a number of revolutions N of about 20,000 rpm.

However, in the screw compressor using the high speed motor as in Patent Document 1, as the size of the motor is smaller, the cooling jacket provided on the outer peripheral portion of the motor casing is smaller. In addition, it is not necessary to cool the motor from the inside. The cooling caused by the smaller cooling jacket is insufficient for the cooling of the motor. In the case where the cooling due to the cooling jacket is insufficiently sufficient, the temperature of the stator coil rises or the temperature of the rotor surface rises, so that the motor output becomes small and the efficiency is lowered.

Therefore, the technical problem to be solved by the present invention is to provide a screw compressor having a cooling structure for cooling a motor in which a spiral rotor is rotationally driven from the inside.

In order to solve the above-described technical problems, according to the present invention, it is possible to provide a screw compressor as follows.

That is, it is characterized by: The compressor main body houses a pair of male and female spiral rotors that are disposed in a horizontal direction in a rotor chamber of the rotor casing; the motor houses a rotor and a stator in a motor housing of the motor casing, and is fixed by the foregoing a motor shaft of the rotor rotationally drives the rotor shaft of the spiral rotor; an oil supply passage for supplying lubricating oil to the oil supply destination; and an intermediate bearing portion for supporting the rotor shaft and disposed on the motor side, and Lubricating by the circulation of the lubricating oil; the oil draining portion is configured to discharge the lubricating oil guided to the motor chamber through the oil supply passage to the motor outside; and the oil recovery portion is to be discharged from the oil draining portion The discharged lubricating oil is recovered.

According to the above configuration, the lubricating oil supplied to the intermediate bearing portion and guided to the motor chamber is cooled by the motor shaft through the motor shaft. The lubricating oil passing through the motor shaft is atomized by the rotor rotating in the motor chamber, and is attached to the rotor, the stator, and the motor shaft in the motor chamber to cool the motor. The lubricating oil used for cooling is recovered to the oil recovery portion without hindering the cooling of the motor. Therefore, the motor that rotationally drives the spiral rotor can be effectively cooled by the lubricating oil supplied to the intermediate bearing portion.

1‧‧‧Spiral compressor (oil-free screw compressor)

2‧‧‧Compressor body

3‧‧‧Spiral rotor

3a‧‧‧Male rotor

3b‧‧‧Female rotor

4‧‧‧Rotor housing

5‧‧‧Motor housing

5a‧‧‧Motor housing body

6‧‧‧Motor

6a‧‧‧Rotor

6b‧‧‧stator

6g‧‧‧ air gap

7‧‧‧ bearing housing

8‧‧‧Cooling sleeve

9‧‧‧ Covers

10‧‧‧Motor shaft oil supply components

10c‧‧‧ oil introduction hole

11‧‧‧Rotor side bearing

12‧‧‧Intermediate bearing department

13‧‧‧Motor-side bearing

14a‧‧‧Intermediate shaft seal

17‧‧‧Rotor room

20‧‧‧Motor room

21‧‧‧Male rotor shaft (rotor shaft)

21c‧‧‧ oil hole

21d‧‧‧Oil export hole

22‧‧‧Female rotor shaft (rotor shaft)

26‧‧‧ screw holes

27‧‧‧ fastening flange

28‧‧‧ fastening bolts (fastening members)

30‧‧‧Motor shaft connecting hole

31‧‧‧Motor shaft

33‧‧‧ center hole

37‧‧‧ bearing support

39‧‧‧Motor shaft connection

41‧‧‧ keys (connecting members)

42‧‧‧ keyway

50‧‧‧ Oil Storage Department

51‧‧‧Motor shaft

54‧‧‧Intermediate communication

63‧‧‧Reservoir drain hole (oil drain)

64‧‧‧Intermediate oil supply port

65‧‧‧Rotor side motor room oil supply port (motor room oil supply port)

66‧‧‧Intermediate oil drain (motor compartment drain; oil drain)

67‧‧‧ casing supply port

68‧‧‧ casing drain

69‧‧‧Motor shaft supply port

71‧‧‧ Oil Recovery Department

72‧‧‧Oil cooler

73‧‧‧ oil pump

75‧‧‧Reservoir drain

77‧‧‧Motor room supply port on the motor side (motor room supply port)

78‧‧‧Motor chamber oil drain on the motor side (motor chamber drain port; oil drain)

80‧‧‧ oil supply road

81‧‧‧Rotor side bearing oil supply road

82‧‧‧Intermediate oil supply road

82a‧‧‧Intermediate oil supply hole

82b‧‧‧Connected space

83‧‧‧Rotor side motor room oil supply path (motor room supply path)

84‧‧‧ casing supply road

85‧‧‧Motor shaft oil supply road

86‧‧‧Motor room supply circuit on the motor side (motor room supply path)

90‧‧‧ Oil drain

91‧‧‧Rotor side bearing oil drain

92‧‧‧Intermediate oil drain (motor room drain)

93‧‧‧Motor compartment oil drain on the motor side (motor compartment drain)

94‧‧‧ casing oil drain

95‧‧‧Reservoir and drainage road

[Fig. 1] Fig. 1 is a cross-sectional view showing a screw compressor according to a first embodiment of the present invention.

Fig. 2 is a longitudinal sectional view showing the screw compressor shown in Fig. 1.

Fig. 3 is a partial cross-sectional view showing a motor chamber of the screw compressor shown in Fig. 2.

Fig. 4 is an enlarged cross-sectional view showing the vicinity of a motor-side bearing portion of the screw compressor shown in Fig. 3.

Fig. 5 is an enlarged cross-sectional view showing the vicinity of an intermediate bearing portion of the screw compressor shown in Fig. 3.

[Fig. 6A] is a cross-sectional view of the arrow of the VI-VI line of Fig. 5.

[Fig. 6B] An enlarged cross-sectional view of a specific portion of a modification of the first embodiment.

[Fig. 7] Fig. 7 is a partial cross-sectional view showing a motor chamber of a screw compressor according to a second embodiment of the present invention.

[Fig. 8] Fig. 8 is a longitudinal sectional view showing a screw compressor according to a third embodiment of the present invention.

[Fig. 9] Fig. 9 is a partial cross-sectional view showing the motor chamber of the screw compressor shown in Fig. 8.

(First embodiment)

First, the screw compressor 1 according to the first embodiment of the present invention will be described with reference to Figs. 1 to 6A.

Fig. 1 is a cross-sectional view showing a screw compressor 1 according to a first embodiment. The screw compressor 1 is an oil-free screw compressor. By each other The pair of spiral rotors 3, which are meshed by the male rotor 3a and the female rotor 3b, which are engaged in the unfueled state, are housed in the rotor chamber 17 formed in the rotor casing 4 of the unfueled compressor main body 2. A bearing housing 7 is attached to the suction side end of the rotor housing 4. A motor casing 5 to which the motor 6 is attached is attached to the discharge side end of the rotor casing 4. The motor 6 has a rotor 6a, a stator 6b, and a motor casing 5. The motor casing 5 is provided with a motor casing body 5a, a cooling jacket 8, and a cover member 9. A rotor 6a and a stator 6b are housed in the motor casing main body 5a. The end of the motor casing 5 is closed by a cover member 9.

The discharge port of the gas (not shown) is formed on the motor 6 side of the rotor casing 4; the suction port of the gas (not shown) is formed on the opposite side of the motor 6 of the rotor casing 4. Timing gears (not shown) that mesh with each other are attached to the respective shaft ends on the opposite side of the motor 6 of the male rotor 3a and the female rotor 3b. In general, the male rotor 3a is rotationally driven by the motor 6. The male rotor shaft 21 of the male rotor 3a is rotated by the rotation of the motor shaft 31 of the motor 6, and the timing gear is transmitted, and the female rotor shaft 22 of the female rotor 3b rotates in synchronization with the male rotor shaft 21.

The motor 6 is a drive source for rotating the rotor shaft of the spiral rotor 3 (usually the male rotor shaft 21). The motor 6 is controlled by the number of revolutions by an inverter (not shown), for example, at a high speed rotation of more than 20,000 rpm. The rotor 6a of the motor 6 is fixed to the outer peripheral portion of the motor shaft 31, and the stator 6b is disposed apart from the outside of the rotor 6a. An air gap 6g is formed between the rotor 6a and the stator 6b. In the motor casing 5, the cooling jacket 8 is disposed in the stator 6b and the motor casing so as to be in close contact with the stator 6b. Between the bodies 5a.

The motor shaft 31 has a plurality of different-diameter shaft portions that are reduced in diameter from the spiral rotor 3 side toward the motor-side bearing portion 13 side. As shown in FIG. 3, the motor shaft 31 is composed of, for example, a first shaft portion 44 and a second shaft portion 45. The first shaft portion 44 of the large diameter is locked to the side end surface of the rotor 6a. The rotor 6a is attached to the second shaft portion 45 of the small diameter. The connection hole 32 extends in the axial direction across the entire first shaft portion 44 and one of the second shaft portions 45. The center hole 33 extends in the axial direction across the remaining portion of the second shaft portion 45. In a state where the flange portions of the bearing support body 37 are in contact with the side end faces of the second shaft portion 45 and the rotor 6a, respectively, the mounting bolts 38 are fastened, whereby the rotor 6a is fixed to the motor shaft 31.

The cooling jacket 8 is attached along the inner side surface of the motor casing main body 5a, and is fastened by bolts in a state where the flange portions of the motor casing body 5 abut each other, whereby the cooling jacket 8 is fixed to the motor casing body 5a. A cooling passage 8b for circulating cooling water or cooled lubricating oil is formed in the cooling jacket portion 8a of the cooling jacket 8. The liquid leakage from the cooling passage 8b toward the motor casing body 5a is prevented by the spacers provided on both sides of the cooling passage 8b in the axial direction.

The male rotor shaft 21 of the spiral rotor 3 and the motor shaft 31 of the motor 6 are formed separately, and the shafts 21 and 31 of the both sides are coaxially extended in the horizontal direction (lateral direction), and a key 41 (coupling member) to be described later is used. Linked into one. On the opposite side of the motor 6 of the male rotor shaft 21, the rotor-side bearing portion 11 is supported by the bearing housing 7. The motor 6 side of the male rotor shaft 21 is supported by the rotor casing 4 by the intermediate bearing portion 12. that is, The male rotor shaft 21 is supported by the rotor-side bearing portion 11 and the intermediate bearing portion 12 so as to be supported at both ends. The bearing support body 37 fixed to the motor side end portion of the motor shaft 31 is supported by the cover member 9 by the motor side bearing portion 13. Therefore, the male rotor shaft 21 and the motor shaft 31 which are integrally coupled are coaxially extended in the horizontal direction (lateral direction), and are supported at three portions of the rotor side bearing portion 11, the intermediate bearing portion 12, and the motor side bearing portion 13. (ie 3 points support). On the other hand, the female rotor shaft 22 of the female rotor 3b is supported by the bearing housing 7 and the rotor housing 4 so as to be supported at both ends by the rotor-side bearing portion 15 and the intermediate bearing portion 16 on the opposite side of the motor 6.

The rotor-side bearing portion 11 that supports the male rotor shaft 21 is composed of, for example, a thrust bearing (4-point contact ball bearing) 11a and a radial bearing (roll bearing) 11b. The intermediate bearing portion 12 is composed of, for example, a radial bearing (roller bearing) 12a provided on the spiral rotor 3 side and a thrust bearing (4-point contact ball bearing) 12b provided on the motor side. The thrust bearing 12b is provided on the motor 6 side, whereby the thrust bearing can be withstood by the thrust bearing 12b even if the rotor shaft 21 is extended by thermal expansion. Further, between the radial bearing 12a and the thrust bearing 12b, an intermediate oil supply passage 82 for supplying lubricating oil to the intermediate bearing portion 12 is provided. The motor-side bearing portion 13 is composed of, for example, a radial bearing (deep groove ball bearing).

Further, the rotor-side bearing portion 15 that supports the female rotor shaft 22 is composed of, for example, a thrust bearing (four-point contact ball bearing) 15a and a radial bearing (roll bearing) 15b. The intermediate bearing portion 16 is, for example, a radial bearing (roller bearing) 16a and a thrust bearing (4-point contact ball bearing) 16b. Composition. Further, a bearing that supports at least the rotor shaft (here, the male rotor shaft 21) connected to the motor shaft 31 on the motor 6 side (in the present embodiment, corresponds to the thrust bearing 12b) is a lubricating oil. It is circulated toward the motor 6 side and is lubricated, and an open-type bearing is used. In addition, in the other embodiments, the other types of bearings are open-shaped, and it is only necessary to appropriately determine whether or not to use an open-type bearing in consideration of the load or lubrication of the bearing.

The male rotor shaft 21 between the male rotor 3a and the intermediate bearing portion 12 is provided with an intermediate shaft seal portion 14a. A shaft seal portion 14c is provided to the male rotor shaft 21 between the rotor side bearing portion 11 and the male rotor 3a. The female rotor shaft 22 between the female rotor 3b and the intermediate bearing portion 16 is provided with a shaft seal portion 14b. The female rotor shaft 22 between the rotor-side bearing portion 15 and the female rotor 3b is provided with a shaft seal portion 14d. Each of the shaft seal portions 14a, 14b, 14c, and 14d includes, for example, a visco seal as an oil seal and a mechanical seal as a gas seal. The spiral seal provided on the bearing side prevents the lubricating oil from flowing into the rotor chamber 17. The mechanical seal provided on the side of the spiral rotor 3 prevents the lubricating oil from flowing into the rotor chamber 17 and the excess leakage of the compressed gas from the rotor chamber 17.

The projecting end portion of the bearing support body 37 is inserted into the center hole 33 of the motor shaft 31, and is fastened by the mounting bolt 38 in a state where the flange portion of the bearing support body 37 abuts against the side end surface of the motor shaft 31. Thereby, the bearing support body 37 is fixed to the motor shaft 31, and one end of the center hole 33 on the motor side bearing portion 13 side is closed. As shown in Fig. 3, the inner ring of the motor-side bearing portion 13 is fixed by a ring disposed on the bearing support body 37. 61 is positioned to be unable to move in the axial direction. On the other hand, the motor-side bearing portion 13 is attached to the bearing mounting hole 9a of the cover member 9 with a clearance fit. Thereby, the outer ring of the motor side bearing portion 13 can be moved in the axial direction. In other words, the motor-side bearing portion 13 is assembled to the motor 6 so as to allow sliding of the outer wheel in the axial direction. According to this configuration, even if the motor shaft 31 is extended by thermal expansion, it is possible to prevent an excessive load from being applied to the motor-side bearing portion 13.

The cover member 9 is attached to the cooling jacket 8 so as to close the opening of the motor casing 5. The cover member 9 is fixed to the cooling jacket 8 in a state in which the flange portion of the cover member 9 abuts against the side end surface of the cooling jacket 8 with a bolt.

The shaft diameter of the motor shaft 31 of the motor 6 is larger than the shaft diameter of the male rotor shaft 21 of the spiral rotor 3. The motor shaft 31 of the large diameter is formed with a coupling hole 32 for inserting the connection end portion 24 on the motor 6 side of the male rotor shaft 21. A center hole 33 having a larger diameter than the coupling hole 32 is formed in the motor shaft 31. The central hole 33 and the coupling hole 32 form a through hole that penetrates the inside of the motor shaft 31 in the axial direction, and the motor shaft 31 has a hollow structure. A step is formed on the boundary between the center hole 33 of the large diameter and the connecting hole 32 of the small diameter. The fastening flange 27 can be freely inserted into the center hole 33 by the step of the through hole penetrating the motor shaft 31, but the connection hole 32 is a dead end. The fastening flange 27 has a screw insertion hole and a plurality of flange communication holes 27a. A plurality of flange communication holes 27a communicate with the center hole 33 and the oil guiding hole 21c.

The inner circumferential surface of the coupling hole 32 provided in the motor shaft 31 31b is formed with, for example, a second key groove 31a having a rectangular cross section. The outer peripheral surface 21b provided in the connection end portion 24 of the male rotor shaft 21 is formed with, for example, a first key groove 24a having a rectangular cross section. The key groove 42 having a rectangular cross section is formed in the axial direction by the first key groove 24a and the second key groove 31a. In a state in which the connecting end portion 24 is inserted into the connecting hole 32, the key 41 of the rectangular cross section is sandwiched between the inner peripheral surface 31b of the connecting hole 32 of the motor shaft 31 and the outer peripheral surface 21b of the connecting end portion 24 of the male rotor shaft 21. Configured between. The key 41 is fitted into the key groove 42, whereby the key 41 is fitted to the key groove 42. Therefore, the key 41 functions as a connecting member that integrally connects the motor shaft 31 and the male rotor shaft 21.

A fastening portion 25 is provided inside the connecting end portion 24. The fastening portion 25 includes an oil guiding hole 21c and a screw hole 26 that extend in the axial direction from the end surface of the connecting end portion 24. The oil guide hole 21c has a larger aperture than the screw hole 26. Further, a space between the connection end portion 24 and the fastening flange 27 is provided as a flow path connecting the oil guiding hole 21c and the flange communication hole 27a. Therefore, the lubricating oil passing through the flange communication hole 27a can flow in the annular gap formed between the oil guiding hole 21c and the fastening bolt 28. Between the screw hole 26 of the rotor shaft (here, the male rotor shaft 21) and the first key groove 24a, a plurality of oil discharge holes 21d extending in the direction orthogonal to the axis are formed. The plurality of oil lead-out holes 21d communicate with the oil guide holes 21c and the motor chamber 20. As shown in Fig. 5, a part of the motor shaft communication portion 39 is formed by the center hole 33, the plurality of flange communication holes 27a, and the oil guiding hole 21c communicating with the plurality of oil lead-out holes 21d.

The screw portion 28b of the fastening bolt 28 is screwed to the fastening portion 25 screw holes 26. By fastening the screw insertion hole of the flange 27, the fastening bolt 28 as a fastening member is inserted. When the fastening flange 27 is inserted into the center hole 33 and the fastening bolt 28 is fastened in a state in which the step of the through hole is engaged, the joint end portion 24 of the male rotor shaft 21 is directed toward the motor side bearing portion. Trapped in the direction of 13, the head 28a of the fastening bolt 28 is locked to the fastening flange 27. Therefore, the motor shaft 31 and the male rotor shaft 21 are tightened by the fastening bolts 28. As described above, in a state in which the motor shaft 31 and the male rotor shaft 21 are integrally coupled by the key 41, the motor shaft 31 and the male rotor shaft 21 are tightened by the fastening bolts 28.

The motor shaft 31 and the male rotor shaft 21 are integrally coupled by a key 41 as a connecting member, and the motor shaft 31 and the male rotor shaft 21, which are fastened by the fastening bolt 28 as a fastening member, are connected as a single shaft. Body effect. Further, since the fitting structure used for the key 41 is not affected by the lubricating oil, even if the lubricating oil enters the connecting hole 32 via the male rotor shaft 21 extending in the horizontal direction, the motor shaft 31 can be revolved. The torque is reliably transmitted between the sub-shafts 21.

At this time, the head portion 28a of the fastening bolt 28 is located in the center hole 33 formed so as to penetrate the motor shaft 31 in the axial direction. In detail, the head portion 28a is caught inside the center hole 33 of the motor shaft 31 so as to be located near the axial end surface of the fastening portion 25 of the male rotor shaft 21. That is, it is configured such that the axial length of the fastening bolt 28 is short. According to this configuration, the influence of the thermal expansion of the fastening bolt 28 is reduced, and the fastening can be surely performed. Further, the connecting end portion 24 of the male rotor shaft 21 and the fastening portion 25, and the coupling hole 32 and the center hole 33 of the motor shaft 31 are coaxially extended.

A radial bearing 12a of the intermediate bearing portion 12 is attached to the motor 6 side of the rotor casing 4. The position of the inner ring of the radial bearing 12a with respect to the male rotor shaft 21 is fixed, and the position of the outer wheel of the radial bearing 12a with respect to the rotor casing 4 is fixed by a fixing ring. The bearing support member 19 is attached to the motor 6 side of the rotor casing 4 through the spacer 18. The bearing support member 19 and the spacer 18 are fixed to the motor 6 side of the rotor casing 4 by fastening with bolts. The inner wheel of the thrust bearing 12b is fixed to the position of the male rotor shaft 21 by the lock nut 23a.

Similarly, a radial bearing 16a of the intermediate bearing portion 16 is attached to the motor 6 side of the rotor casing 4. The position of the inner ring of the radial bearing 16a to the female rotor shaft 22 is fixed, and the position of the outer wheel of the radial bearing 16a to the rotor casing 4 is fixed by a fixing ring. The inner wheel of the thrust bearing 16b is fixed to the position of the female rotor shaft 22 by the lock nut 23b.

Further, the inner ring, the outer ring, and the rolling elements constituting the bearing are usually formed of a steel material and have electrical conductivity. Therefore, the high-frequency current from the inverter circuit of the motor 6 flows to the intermediate bearing portion 12 and the motor-side bearing portion 13 of the motor shaft 31 supporting the motor 6, the outer bearing of the intermediate bearing portion 12 and the motor-side bearing portion 13, and A shaft voltage is generated between the inner wheels, which causes damage to the current corrosion of the bearing. Therefore, the intermediate bearing portion 12 and the motor-side bearing portion 13 are electrically insulated. The bearing is electrically insulated, such as an inorganic insulating material such as a rolling system ceramic of a bearing, or the outer surface of at least one of the inner and outer wheels of the bearing is subjected to an organic insulating material such as an epoxy resin or an unsaturated polyester resin. Covered. another Further, in the support member or the outer casing supporting the bearing, the portion abutting the bearing may be covered with an insulating material. By electrically insulating the intermediate bearing portion 12 and the motor-side bearing portion 13 in this manner, the high-frequency current from the inverter circuit of the motor 6 causes the electric corrosion of the bearing portions 12 and 13 to be less likely to occur.

(cooling structure of the motor due to lubricating oil)

Next, in the first embodiment, a cooling structure in which the screw 6 that rotates the spiral rotor 3 at a high speed is cooled by lubricating oil will be described.

As shown in FIG. 2, the intermediate oil supply port 64 that communicates with the intermediate oil supply passage 82 is formed in the upper portion of the rotor casing 4. The intermediate oil supply hole 82a extending from the intermediate oil supply port 64 to the intermediate bearing portion 12 is formed inside the rotor casing 4. The radial bearing 12a and the thrust bearing 12b are separated by the spacer 18. A communication space 82b is formed between the separated radial bearing 12a and the thrust bearing 12b. The intermediate oil supply hole 82a is connected to the communication space 82b. Therefore, the intermediate oil supply passage 82 is transmitted to the communication space 82b through the intermediate oil supply hole 82a in the rotor casing 4.

The lubricating oil supplied to the intermediate oil supply passage 82 is supplied to the radial bearing 12a and the thrust bearing 12b of the intermediate bearing portion 12 through the communication space 82b. The lubricating oil supplied to the radial bearing 12a is used for lubrication and cooling of the radial bearing 12a. The lubricating oil is restricted by the oil seal of the intermediate shaft seal portion 14a toward the rotor chamber 17. On the other hand, the rotor casing 4 is provided with an intermediate communication portion 54 which is formed at one end and a gap portion formed between the radial bearing 12a and the intermediate shaft seal portion 14a. The other end is in communication with the motor chamber 20. The lubricating oil that is to flow from the radial bearing 12a toward the spiral rotor 3 side is guided into the motor chamber 20 through the intermediate communication portion 54. The lubricating oil guided into the motor chamber 20 through the intermediate communication portion 54 is discharged from the oil discharge portion to the outside of the motor chamber 20 and collected in the oil recovery portion 71.

Therefore, by providing the intermediate communication portion 54, when the radial bearing 12a is open, it is possible to prevent the lubricating oil from flowing into the rotor chamber 17 beyond the intermediate shaft seal portion 14a. In particular, in the multi-stage compressor in which the plurality of motors 6 can individually adjust the number of revolutions, if the spiral rotor 3 of the low-pressure stage includes the intermediate communication portion 54, the negative pressure can be effectively performed even when the discharge side of the low-pressure section is negative. The lubricating oil is prevented from flowing into the rotor chamber 17.

The lubricating oil supplied to the thrust bearing 12b is used for lubrication and cooling of the thrust bearing 12b. The lubricating oil that is lubricated and cooled while flowing through the thrust bearing 12b is guided into the motor chamber 20, and the motor shaft 31 is cooled from the outer surface. The lubricating oil is atomized into an oil mist by the motor shaft 31 and the rotor 6a that rotate at high speed in the motor chamber 20. The lubricating oil that is atomized by the oil adheres to the rotor 6a, the stator 6b, and the motor shaft 31 in the motor chamber 20, and cools the motor 6 from the inside of the motor chamber 20.

The motor-side oil supply port 65 on the rotor side that communicates with the motor-chamber oil supply path 83 on the rotor side is formed on the upper portion of the motor chamber 20 on the side of the intermediate bearing portion 12, that is, the upper portion of the motor casing 5 on the side of the intermediate bearing portion 12. . The motor chamber supply passage 83 on the rotor side and the motor chamber supply port 65 on the rotor side function as a motor chamber supply passage and a motor chamber supply port, respectively. The motor chamber oil supply port 65 on the rotor side is provided with a spray capable of spraying the lubricating oil in a particulate form. Shot nozzle (not shown).

The lubricating oil supplied to the motor chamber supply passage 83 on the rotor side is guided into the motor chamber 20 through the nozzle. The lubricating oil guided into the motor chamber 20 is attached to the rotor 6a, the stator 6b, and the motor shaft 31 in the motor chamber 20, and the motor 6 is cooled.

The intermediate oil discharge port 66 that communicates with the intermediate oil drain passage 92 is formed at the bottom of the motor chamber 20 on the side of the intermediate bearing portion 12, that is, the bottom of the motor housing 5 on the side of the intermediate bearing portion 12. The intermediate oil drain passage 92 and the intermediate oil discharge port 66 function as a motor chamber drain passage and a motor chamber drain port (oil drain portion), respectively. The lubricating oil used for the lubrication of the intermediate bearing portion 12 and the cooling of the motor 6 is collected at the bottom of the motor chamber 20 on the side of the intermediate bearing portion 12, and is discharged to the outside of the motor chamber 20 through the intermediate oil discharge port 66. This lubricating oil is recovered to the oil recovery portion 71 through the intermediate oil drain passage 92.

The motor-side oil supply port 77 that communicates with the motor-side oil supply passage 86 on the motor side is formed on the upper portion of the motor chamber 20 on the motor-side bearing portion 13 side, that is, as a cooling jacket on the motor-side bearing portion 13 side. The upper part of the motor housing 5 of 8. The motor chamber supply passage 86 on the motor side and the motor chamber supply port 77 on the motor side function as a motor chamber supply passage and a motor chamber supply port, respectively. The motor chamber oil supply port 77 on the motor side is opened so that the lubricating oil flows out toward the winding of the stator 6b. A motor-side bearing oil supply hole 79 is formed in an upper portion of the cover member 9 located below the winding of the stator 6b. The motor-side bearing oil supply hole 79 is an oil receiving portion having an upper portion that expands the opening area in a concave shape.

Lubrication of the oil supply path 86 supplied to the motor side The oil is supplied into the motor chamber 20 through the motor chamber oil supply port 77 on the motor side, and the winding of the stator 6b is cooled. The lubricating oil flowing down the windings of the stator 6b is collected by the oil receiving portion, and is supplied to the motor-side bearing portion 13 through the motor-side bearing oil supply hole 79. The lubricating oil supplied to the motor-side bearing portion 13 is used for lubrication and cooling of the motor-side bearing portion 13. The lubricating oil that has lubricated and cooled the motor-side bearing portion 13 is guided into the motor chamber 20.

The motor-side oil discharge port 78 that communicates with the motor-side oil drain passage 93 on the motor side is formed at the bottom of the motor chamber 20 on the motor-side bearing portion 13 side, that is, as a cooling jacket on the motor-side bearing portion 13 side. The bottom of the motor housing 5 of 8. The motor chamber drain passage 93 on the motor side and the motor chamber drain port 78 on the motor side function as a motor chamber drain passage and a motor chamber drain port (oil drain portion), respectively. The lubricating oil used for the lubrication of the motor-side bearing portion 13 and the cooling of the windings of the stator 6b of the motor 6 is concentrated at the bottom of the motor chamber 20 on the motor-side bearing portion 13 side, and passes through the motor-side oil discharge port 78 on the motor side. And is discharged to the outside of the motor chamber 20. This lubricating oil is recovered to the oil recovery portion 71 through the motor chamber drain passage 93 on the motor side.

A rotor-side bearing oil supply port (not shown) that communicates with the rotor-side bearing oil supply passage 81 is formed in the upper portion of the bearing housing 7 on the rotor-side bearing portion 11 side. Inside the bearing housing 7, a rotor-side bearing oil supply hole (not shown) that extends from the rotor-side bearing oil supply port to the rotor-side bearing portion 11 is formed.

The lubricating oil supplied to the rotor-side bearing oil supply passage 81 is supplied to the rotor-side bearing portion 11 through the rotor-side bearing oil supply hole. Be The lubricating oil supplied to the rotor-side bearing portion 11 is used for lubrication and cooling of the rotor-side bearing portion 11. The lubricating oil that has lubricated and cooled the rotor-side bearing portion 11 is restricted by the oil seal of the shaft seal portion 14c toward the rotor chamber 17.

A rotor-side bearing oil discharge port (not shown) that communicates from the rotor-side bearing portion 11 to the rotor-side bearing oil drain passage 91 is formed at the bottom of the bearing housing 7. The lubricating oil used for lubrication and cooling of the rotor-side bearing portion 11 is discharged to the outside of the bearing housing 7 through the rotor-side bearing oil discharge port. This lubricating oil is recovered to the oil recovery portion 71 by the rotor-side bearing oil drain passage 91.

In the upper portion of the motor casing 5, a casing oil supply port 67 communicating with the casing oil supply passage 84 is formed. The casing oil supply port 67 is in communication with the cooling passage 8b. The lubricating oil supplied to the casing oil supply passage 84 is supplied to the cooling passage 8b through the casing oil supply port 67, and the stator 6b is cooled.

A sleeve drain port 68 that communicates with the casing drain passage 94 is formed in a lower portion of the motor casing 5. The downstream side of the cooling jacket 8 is connected to a casing oil drain passage 94 constituting a part of the oil discharge passage 90. The casing drain port 68 is in communication with the cooling passage 8b. The lubricating oil that has flowed through the cooling passage 8b is discharged to the motor casing 5 through the casing drain port 68. This lubricating oil is recovered to the oil recovery portion 71 through the casing drain passage 94. Therefore, the lubricating oil that lubricates and cools the bearing portions 11, 12, and 13 flows to the cooling passage 8b of the cooling jacket portion 8a, whereby the cooling of the stator 6b of the motor 6 can also be utilized.

As shown in Fig. 3, the motor shaft oil supply member 10 is provided with The mounting flange 10a and the protruding portion 10b are attached to the opening portion of the side surface of the cover member 9 in a sealed state. A motor shaft oil supply port 69 is formed in a central portion of the mounting flange 10a. An oil introduction hole 10c is formed inside the protruding portion 10b extending in the axial direction. The oil introduction hole 10c is a through hole extending in the axial direction, and communicates with the motor shaft oil supply port 69 and the insertion hole 37c of the bearing support body 37.

An insertion hole 37c is formed in a central portion of the bearing support body 37. The insertion hole 37c is larger than the protruding portion 10b of the motor shaft oil supply member 10, and is a through hole through which the protruding portion 10b can be inserted in the axial direction with a slight gap therebetween. The oil introduction hole 10c and the insertion hole 37c are disposed coaxially with respect to the center hole 33. A part of the protruding portion 10b is inserted into the insertion hole 37c so that the end portion of the protruding portion 10b overlaps the insertion hole 37c in the axial direction. As shown in Fig. 4, a part of the motor shaft communication portion 39 is formed by the oil introduction hole 10c and the insertion hole 37c communicating with the center hole 33.

Therefore, the motor shaft communication portion 39 is configured by the oil introduction hole 10c, the insertion hole 37c, the center hole 33, the plurality of flange communication holes 27a, and the oil guide hole 21c communicating with the plurality of oil outlet holes 21d. According to this configuration, the lubricating oil supplied from the motor shaft oil supply port 69 that communicates with the motor shaft oil supply passage 85 flows in the center hole 33 formed in the motor shaft 31, and the rotor 6a is inside (inside). cool down. The lubricating oil flowing through the center hole 33 cools the motor shaft 31 from the inside (inside). Further, the center hole 33 extending in the axial direction along the rotor 6a is further expanded in diameter than the insertion hole 37c (in the present embodiment, the diameter is increased to 3 times the diameter). on). Thereby, the surface area (heat transfer surface) of the center hole 33 can be made large, and the cooling effect of the rotor 6a can be improved.

The lubricating oil that flows through the center hole 33 and cools the rotor 6a of the motor 6 from the inside flows out from the plurality of oil lead-out holes 21d. The lubricating oil that has flowed out of the plurality of oil outlet holes 21d is atomized into an oil mist by the motor shaft 31 and the rotor 6a that rotate at high speed in the motor chamber 20. The lubricating oil that is atomized by the oil adheres to the rotor 6a, the stator 6b, and the motor shaft 31 in the motor chamber 20, and cools the motor 6. The lubricating oil used for cooling of the motor 6 is discharged to the outside of the motor chamber 20 through the intermediate oil drain port 66. This lubricating oil is recovered to the oil recovery portion 71 through the intermediate oil drain passage 92.

The rotor side bearing oil discharge passage 91, the intermediate oil discharge passage 92, the motor side oil discharge passage 93 on the motor side, and the casing oil discharge passage 94 are merged to constitute the oil discharge passage 90. The oil draining path 90 is connected to the oil recovery part 71 that recovers the lubricating oil. On the downstream side of the oil recovery unit 71, an oil cooler 72 that cools the recovered lubricating oil is provided. The oil supply passage 80 for supplying the lubricating oil to the oil supply destination is connected to the downstream side of the oil pump 73. The oil supply destination is the rotor side bearing portion 11, the intermediate bearing portions 12, 16, the motor side bearing portion 13, and the like. In the present embodiment, as the cooling medium, lubricating oil is supplied to the cooling jacket 8 and the center hole 33 of the motor shaft 31 in the motor chamber 20. Therefore, the oil supply passage 80 is divided into a rotor side bearing oil supply passage 81, an intermediate oil supply passage 82, a rotor side motor chamber oil supply passage 83, a casing oil supply passage 84, a motor shaft oil supply passage 85, and a motor side. The motor room supply passage 86. Each of the oil supply passages 81, 82, 83, 84, 85, and 86 is connected to the respective rotation The sub-side bearing oil supply port, the intermediate oil supply port 64, the rotor-side motor chamber oil supply port 65, the casing oil supply port 67, the motor shaft oil supply port 69, and the motor-side motor chamber oil supply port 77. Therefore, the lubricating oil is repeated in the following processes: supplied to the compressor body 2 and the respective oil supply destinations of the motor 6 which must be lubricated and cooled, and used for lubrication and cooling of the respective oil supply destinations, after which the lubricating oil is recovered. The oil recovery unit 71 is cooled to the oil cooler 72. In this manner, the lubricating oil is circulated in the screw compressor 1 and used.

As described above, the motor casing 5 is attached to the discharge side of the rotor casing 4, and the motor shaft 31 of the motor 6 extends to the discharge side of the rotor casing 4. The discharge side of the rotor casing 4 is heated by the gas compression by the spiral rotor 3, and the motor shaft 31 also becomes high temperature. The motor shaft 31 that has become high in temperature is cooled by the lubricating oil, and the cooling effect by the lubricating oil is more exhibited.

In the above embodiment, as shown in FIG. 6A, in the male rotor shaft 21 and the motor shaft 31, the shaft diameter of the motor shaft 31 is configured to be larger than the shaft diameter of the male rotor shaft 21. Further, the motor shaft 31 is coupled to the male rotor shaft 21 by inserting the coupling end portion 24 of the male rotor shaft 21 into the coupling hole 32 formed in the motor shaft 31. The motor shaft 31 functions as one of the shafts, and the male rotor shaft 21 functions as the other shaft.

On the other hand, as in the modification shown in FIG. 6B, the axial diameter of the male rotor shaft 21 is larger than the axial diameter of the motor shaft 31, and the male rotor shaft 21 can be configured to function as one shaft. The motor shaft 31 acts as the other shaft. The outer peripheral surface 34b provided in the connecting end portion 34 of the motor shaft 31 is formed with, for example, a second key groove having a rectangular cross section. 31a. The inner peripheral surface 24b of the connection hole 23 provided in the male rotor shaft 21 is formed with, for example, a first key groove 24a having a rectangular cross section. The key groove 42 having a rectangular cross section is formed by the first key groove 24a and the second key groove 31a.

In a state in which the connecting end portion 34 of the motor shaft 31 is inserted into the coupling hole 23 of the male rotor shaft 21, the key 41 of the rectangular cross section is sandwiched between the outer peripheral surface 34b of the connecting end portion 34 of the motor shaft 31 and the male rotor shaft 21. The inner peripheral surface 24b of the connection hole 23 is disposed between. The key 41 is fitted into the key groove 42, whereby the key 41 is fitted to the key groove 42. Therefore, the motor shaft 31 and the male rotor shaft 21 are integrally connected by the key 41 acting as a coupling member.

(Second embodiment)

Next, a second embodiment of the present invention will be described with reference to Fig. 7. In the second embodiment, constituent elements having the same functions as those of the constituent elements in the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated.

In the screw compressor 1 of the second embodiment, the male rotor shaft 21 also serves as the motor shaft portion 51, and the male rotor shaft 21 and the motor shaft portion 51 are constituted by one shaft body.

The motor 6 side of the male rotor shaft 21 extends from the portion on the side of the motor 6 of the lock nut 23a to the portion of the motor-side bearing portion 13, and constitutes the motor shaft portion 51. A motor shaft communication hole 30 is formed inside the motor shaft portion 51. The motor shaft communication hole 30 extends in the axial direction and communicates with the end face opening of the motor side bearing portion 13 side and a plurality of oil guides Outlet 21d. A part of the protruding portion 10b is inserted into the motor shaft communication hole 30 such that the end portion of the protruding portion 10b of the motor shaft oil supply member 10 overlaps the insertion hole 37c in the axial direction. Further, the motor shaft communication portion 39 is configured by the oil introduction hole 10c and the motor shaft communication hole 30 communicating with the plurality of oil outlet holes 21d.

According to this configuration, the lubricating oil supplied from the motor shaft oil supply port 69 connected to the motor shaft oil supply passage 85 flows in the motor shaft communication hole 30 formed in the motor shaft portion 51. The lubricating oil flowing through the motor shaft communication hole 30 cools the motor shaft 31 and further cools the rotor 6a.

The lubricating oil flowing through the motor shaft communication hole 30 and used for cooling by the motor 6 flows out from the plurality of oil lead-out holes 21d and is atomized by oil, and adheres to the rotor 6a and the stator 6b in the motor chamber 20. And the motor shaft 31 cools the motor 6. The lubricating oil used for cooling of the motor 6 is discharged to the outside of the motor chamber 20 through the intermediate oil drain port 66, and is recovered to the oil recovery portion 71 by the intermediate oil drain passage 92.

(Third embodiment)

Next, a third embodiment of the present invention will be described with reference to Figs. 8 and 9. In the third embodiment, constituent elements having the same functions as those of the constituent elements in the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated.

In the screw compressor 1 of the third embodiment, the motor-side oil discharge port 78 (shown in FIG. 2) on the motor-side bearing portion 13 side is closed, and is formed to be discharged to the motor chamber 20. Lubricating oil The oil storage hole (the oil draining portion) 63 that is adjusted in the oil level of the oil stored in the oil reservoir 50 is adjusted.

The motor-side oil discharge port 78 on the motor side of the motor-side bearing portion 13 is closed by, for example, a closing plug, and is configured such that the lubricating oil does not pass from the motor-side oil discharge port 78 on the motor side shown in FIG. Flow out. The oil reservoir portion 50 is a lower portion of the motor chamber 20 on the motor-side bearing portion 13 side, and a lower side portion of the stator 6b on the motor-side bearing portion 13 side and the motor casing 5 (in the present embodiment, cooling) The lower side portion and the bottom surface portion of the sleeve 8) are formed. The oil reservoir portion 50 communicates with the motor chamber oil supply port 77 on the motor side, and stores the lubricating oil supplied to the motor chamber 20 on the motor side bearing portion 13 side.

The storage and discharge port 75 that communicates with the storage and draining passage 95 is formed on the side of the motor casing 5 that is the side of the motor chamber 20 (in the present embodiment, the side of the cooling jacket 8), or It is the side of the cooling jacket 8 and the cover member 9. The reservoir drain hole 63 communicates with the oil reservoir portion 50 and the reservoir drain port 75 to function as an oil drain portion. The oil storage hole 63 is configured to adjust the oil level of the oil stored in the oil reservoir 50 so that the lowermost portion of the air gap 6g formed between the rotor 6a and the stator 6b is immersed in the lubricating oil. In the present embodiment, the storage and drain holes 63 are disposed at a position lower than the lowermost portion of the air gap 6g. At this time, by adjusting the amount of oil discharged by the storage drain hole 63, the oil level can be adjusted. Further, the oil storage hole 63 may be adjusted in height by setting the height of the oil flow (the height of the oil flow). The storage and drain hole 63 may extend in a substantially horizontal direction or an obliquely downward direction.

As described above, the lubricating oil that has flowed into the motor chamber 20 and cools the motor 6 is collected in the oil reservoir portion 50 and stored. The lubricating oil stored in the oil retaining portion 50 is adjusted to a desired oil level by the storage drain hole 63, and is discharged to the outside of the motor chamber 20. Therefore, the oil level of the lubricating oil stored in the oil reservoir portion 50 can be located slightly above the air gap 6g of the lowermost portion. Therefore, the rotor 6a can be cooled by heat exchange with the lubricating oil that is in contact with the cooled stator 6b. On the other hand, it is also possible to adjust the oil level to be located only slightly below the lowermost air gap 6g. At this time, the lubricating oil is prevented from entering the air gap 6g, whereby the rotor 6a can smoothly rotate to suppress the occurrence of the rotation loss. Further, since the lower portion of the stator 6b is cooled by the lubricating oil stored in the oil reservoir portion 50, the cooling effect of the motor 6 can be improved. Further, the lubricating oil discharged to the outside of the motor chamber 20 by the oil drain hole 63 is recovered to the oil recovery portion 71 by the storage and drain passage 95.

Further, as shown in the first embodiment, the rotor shaft 21 of the spiral rotor 3 and the motor shaft 31 of the motor 6 may be configured separately, or as shown in the second embodiment, the male rotor shaft 21 also serves as the motor shaft portion 51 and revolves. The sub-shaft 21 and the motor shaft portion 51 may be constituted by one shaft body.

In addition, in the above-described embodiment, the oil recovery unit 71 is not described in detail, and the oil recovery unit 71 may be at least a space for collecting the lubricating oil discharged to the motor chamber 20 . For example, the oil recovery unit 71 may be configured by an oil groove provided separately from the motor chamber 20, and may be configured integrally with the motor case 5.

Further, in the above embodiment, the key 41 is used as the A connecting member for integrally connecting the motor shaft 31 and the male rotor shaft 21 may be a tapered ring (also referred to as a locking assembly) as the connecting member. Further, the tapered ring connects the motor shaft 31 and the male rotor shaft 21 by the frictional force generated by the circumferential surface of the ring which is disposed in the installation space between the motor shaft 31 and the male rotor shaft 21. The tapered ring is formed by combining a wedge-shaped inner ring having one inclined surface and a wedge-shaped outer ring having the other inclined surface engaged with the one inclined surface.

Further, the configuration of the rotor-side bearing portion 11, the intermediate bearing portion 12, or the motor-side bearing portion 13, and the configuration of each of the shaft seal portions 14a, 14b, 14c, and 14d are not limited to the above-described embodiments. The screw compressor 1 having the above-described cooling structure is, for example, an oil-free type that is rotationally driven at a high speed of about 20,000 rpm. In addition, the cooling oil is introduced into the rotor chamber 17 and is rotationally driven at a low speed of about 3000 rpm. Oil-cooled can also be used.

Further, in order to remove the cooling jacket 8, a cooling passage 8b through which the lubricating oil for cooling the stator 6b of the motor 6 flows may be formed in the motor casing main body 5a. At this time, the stator 6b is directly attached to the inner wall surface of the motor casing main body 5a.

In addition, the "rotor side" of the "rotor side bearing portion 11, the rotor side bearing oil supply path 81, and the rotor side bearing oil discharge path 91" in the present specification is located on the spiral rotor 3 side of the compressor main body 2. It is not intended to be located on the side of the rotor 6a of the motor 6.

As is apparent from the above description, the screw compressor 1 of the present invention includes the compressor main body 2 and is housed in the rotor chamber 17 of the rotor casing 4. The spiral rotor 3 that accommodates a pair of male and female arms that are engaged with each other in the horizontal direction is housed; the motor 6 houses the rotor 6a and the stator 6b in the motor chamber 20 of the motor casing 5, and is fixed to the motor of the rotor 6a. The shaft 31 rotationally drives the rotor shaft 21 of the spiral rotor 3; the oil supply passage 80 is for supplying lubricating oil to the oil supply destination; and the intermediate bearing portion 12 is for supporting the rotor shaft 21 and is provided to the motor. 6 side, and is lubricated by the circulation of the lubricating oil; the oil discharge portions 66, 78 are for discharging the lubricating oil guided into the motor chamber 20 through the oil supply passage 80 to the outside of the motor chamber 20; The oil recovery unit 71 collects the lubricating oil discharged from the oil draining units 66 and 78.

According to the above configuration, the lubricating oil supplied to the intermediate bearing portion 12 and guided into the motor chamber 20 is cooled by the motor shaft 31 via the motor shaft 31. The lubricating oil that has passed through the motor shaft 31 is atomized by the motor shaft 31 and the rotor 6a that rotate in the motor chamber 20, and adheres to the rotor 6a, the stator 6b, and the motor shaft 31 in the motor chamber 20, and the motor 6 cooling. The lubricating oil used for cooling is recovered to the oil recovery portion 71 without hindering the cooling of the motor 6. Therefore, the motor 6 that rotationally drives the spiral rotor 3 can be effectively cooled by the lubricating oil supplied to the intermediate bearing portion 12.

The present invention can also have the following features in addition to the above features.

In other words, the screw compressor 1 further includes a rotor-side bearing portion 11 provided on the opposite side of the intermediate bearing portion 12 for supporting the rotor shaft 21 at both ends, and a motor-side bearing portion 13 The motor shaft 31 that extends coaxially with respect to the rotor shaft 21; the oil reservoir portion 50 is configured to store lubricating oil supplied to the motor-side bearing portion 13 to be formed in the motor-side bearing portion 13 a lower portion of the motor chamber 20 on the side; and a draining oil drain hole for discharging the lubricating oil to the outside of the motor chamber 20 as the oil drain hole, thereby adjusting the oil level of the oil stored in the oil reservoir portion 50 height. According to this configuration, the lubricating oil stored in the oil reservoir portion 50 is adjusted to a desired oil level by the storage drain hole 63, and is discharged to the outside of the motor chamber 20. Therefore, the oil level of the lubricating oil stored in the oil reservoir portion 50 can be located slightly above the air gap 6g of the lowermost portion. Therefore, the rotor 6a can be cooled by heat exchange with the lubricating oil that is in contact with the cooled stator 6b. On the other hand, it is also possible to adjust the oil level to be located only slightly below the lowermost air gap 6g. At this time, the lubricating oil is prevented from entering the air gap 6g, whereby the rotor 6a can smoothly rotate to suppress the occurrence of the rotation loss. Further, since the lower portion of the stator 6b is cooled by the lubricating oil stored in the oil reservoir portion 50, the cooling effect of the motor 6 can be improved.

The discharge side of the rotor casing 4 is connected to the motor casing 5. According to this configuration, the motor shaft 31 of the motor 6 extends on the discharge side of the rotor casing 4. Further, the discharge side of the rotor case 4 is heated by the gas compression by the spiral rotor 3, and the motor shaft 31 also becomes high temperature. The motor shaft 31 that has become high in temperature is cooled by the lubricating oil, and the cooling effect by the lubricating oil is more exhibited.

Between the intermediate bearing portion 12 and the intermediate shaft seal portion 14a, an intermediate communication portion for connecting the motor chamber 20 is provided. 54. According to this configuration, even when the intermediate bearing portion 12 is open, it is possible to prevent the lubricating oil from flowing into the rotor chamber 17 beyond the intermediate shaft seal portion 14a. In particular, in the multi-stage compressor in which the plurality of motors 6 can individually adjust the number of revolutions, if the spiral rotor 3 of the low-pressure section is provided with the intermediate communication portion 54, the negative pressure can be effectively prevented even when the discharge side of the low-pressure section is a negative pressure. The lubricating oil flows into the rotor chamber 17.

The intermediate bearing portion 12 is formed by a radial bearing 12a provided on the spiral rotor 3 side and a thrust bearing 12b provided on the motor side, between the radial bearing 12a and the thrust bearing 12b. An intermediate oil supply passage 82 for supplying lubricating oil to the intermediate bearing portion 12 is provided. According to this configuration, the thrust bearing 12b is provided on the motor side, and even if the rotor shaft 21 is extended by thermal expansion, the thrust bearing 12b can receive the thrust load.

The motor-side bearing portion 13 is assembled to the motor 6 so as to allow sliding of the outer wheel in the axial direction. According to this configuration, even if the motor shaft 31 is extended by thermal expansion, it is possible to prevent an excessive load from being applied to the motor-side bearing portion 13.

An oil cooler 72 is provided in the middle of the oil supply passage 80 for supplying the lubricating oil to the oil supply destination from the oil recovery unit 71. According to this configuration, the lubricating oil can be recycled.

The oil supply passage 80 includes a casing oil supply passage 84 connected to a cooling jacket 8 that cools the stator 6b of the motor 6, and a downstream side of the cooling jacket 8 is connected to the oil recovery portion 71. According to this configuration, the lubricating oil for lubricating and cooling the bearing portions 11, 12, and 13 can be utilized. Cooling of the stator 6b of the motor 6.

The oil supply passage 80 further includes motor chamber supply passages 83 and 86 that are connected to the motor chamber supply ports 65 and 77 that supply the lubricating oil from the upper portion of the motor chamber 20. According to this configuration, the lubricating oil for lubricating and cooling the bearing portions 11, 12, and 13 can be atomized by oil and used for cooling the stator 6b of the motor 6.

1‧‧‧Spiral compressor

2‧‧‧Compressor body

3‧‧‧Spiral rotor

3a‧‧‧Male rotor

4‧‧‧Rotor housing

5‧‧‧Motor housing

5a‧‧‧Motor housing body

6‧‧‧: Motor

6a‧‧‧Rotor

6b‧‧‧stator

7‧‧‧ bearing housing

8‧‧‧Cooling sleeve

8a‧‧‧Cooling section

8b‧‧‧Cooling path

9‧‧‧ Covers

10‧‧‧Motor shaft oil supply components

11‧‧‧Rotor side bearing

11a‧‧‧ thrust bearing

11b‧‧‧ radial bearing

12‧‧‧Intermediate bearing department

12a‧‧‧radial bearing

12b‧‧‧ thrust bearing

13‧‧‧Motor-side bearing

14a‧‧‧Intermediate shaft seal

14c‧‧‧ shaft seal

17‧‧‧Rotor room

20‧‧‧Motor room

21‧‧‧Male rotor shaft (rotor shaft)

23a‧‧‧Lock nut

24‧‧‧Link end

27‧‧‧ fastening flange

28‧‧‧ fastening bolts (fastening members)

31‧‧‧Motor shaft

33‧‧‧ center hole

37‧‧‧ bearing support

41‧‧‧ keys (connecting members)

42‧‧‧ keyway

54‧‧‧Intermediate communication

64‧‧‧Intermediate oil supply port

65‧‧‧Rotor side motor room oil supply port (motor room oil supply port)

66‧‧‧Intermediate oil drain (motor compartment drain; oil drain)

69‧‧‧Motor shaft supply port

71‧‧‧ Oil Recovery Department

72‧‧‧Oil cooler

73‧‧‧ oil pump

77‧‧‧Motor room supply port on the motor side (motor room supply port)

78‧‧‧Motor chamber oil drain on the motor side (motor chamber drain port; oil drain)

79‧‧‧Motor-side bearing oil supply hole

80‧‧‧ oil supply road

81‧‧‧Rotor side bearing oil supply road

82‧‧‧Intermediate oil supply road

82a‧‧‧Intermediate oil supply hole

82b‧‧‧Connected space

83‧‧‧Rotor side motor room oil supply path (motor room supply path)

84‧‧‧ casing supply road

85‧‧‧Motor shaft oil supply road

86‧‧‧Motor room supply circuit on the motor side (motor room supply path)

90‧‧‧ Oil drain

91‧‧‧Rotor side bearing oil drain

92‧‧‧Intermediate oil drain (motor room drain)

93‧‧‧Motor compartment oil drain on the motor side (motor compartment drain)

94‧‧‧ casing oil drain

Claims (9)

A screw compressor includes a compressor main body in which a pair of male and female spiral rotors that are engaged with each other in a horizontal direction are housed in a rotor chamber of a rotor casing, and a motor that houses a rotor in a motor housing of the motor casing and a stator, wherein the rotor shaft of the spiral rotor is rotationally driven by a motor shaft fixed to the rotor; the oil supply path is for supplying lubricating oil to the oil supply destination; and the intermediate bearing portion is for supporting the rotor shaft And being disposed on the motor side and being lubricated by the flow of the lubricating oil; the oil draining portion is configured to discharge the lubricating oil guided into the motor chamber through the oil supply passage to the motor outside; and the oil recovery unit The lubricating oil discharged from the oil draining portion is recovered. The screw compressor according to claim 1, further comprising: a rotor-side bearing portion provided on the opposite side of the intermediate bearing portion for supporting the rotor shaft at both ends; and a motor-side bearing The motor is configured to support the motor shaft that extends coaxially with respect to the rotor shaft, and the oil reservoir portion is configured to store lubricating oil supplied to the motor-side bearing portion and to be formed on the motor-side bearing portion side. The lower portion of the motor chamber and the oil storage hole are configured to discharge the lubricating oil to the outside of the motor as the oil discharge portion, thereby adjusting the oil level of the oil stored in the oil storage portion. The screw compressor according to claim 1, wherein the discharge side of the rotor casing is connected to the motor casing. The screw compressor according to claim 1, wherein an intermediate communication portion for connecting the motor chamber is provided between the intermediate bearing portion and the intermediate shaft seal portion. The screw compressor according to any one of claims 1 to 4, wherein the intermediate bearing portion is formed by a radial bearing provided on the spiral rotor side and a thrust bearing provided on the motor side. An intermediate oil supply passage for supplying lubricating oil to the intermediate bearing portion is provided between the radial bearing and the thrust bearing. The screw compressor according to the second aspect of the invention, wherein the motor-side bearing portion is assembled to the motor so as to allow sliding of an outer wheel in an axial direction. The screw compressor according to the first aspect of the invention, wherein the oil cooler is provided in the middle of the oil supply passage for supplying the lubricating oil to the oil supply destination from the oil recovery unit. The screw compressor according to claim 7, wherein the oil supply passage includes a casing oil supply passage connected to a cooling jacket that cools the stator of the motor, and a downstream side of the cooling jacket Connected to the aforementioned oil recovery unit. The screw compressor according to claim 7 or 8, wherein the oil supply passage further includes: a motor chamber supply passage connected to a motor chamber oil supply port for supplying lubricating oil from an upper portion of the motor chamber .