JPS59215986A - Screw compressor - Google Patents

Abstract

PURPOSE:To prevent a motor from overheating without using any oil tank separately by sucking refrigerant through the motor an arranging and outer casing with a gap against a casing of a screw compressor. CONSTITUTION:On a partition wall between a rotor casing part 1a and a motor frame part 25a, a suction port 21 of a screw compressor is bored. An outer casing 38 is hermetically brought in contact with a flange 39 with a gap to the periphery of the rotor casing part 1a, which is completely covered. The refrigerant gas discharged into the outer casing 38 from a discharge port 22 is conducted through a de-mister 41 to the delivery side, while the oil in the refrigerant is separated and dropped to an oil reservoir part 46.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hermetic screw compressor mainly used for refrigerators.

FIG. 1 is a longitudinal sectional view of a conventional hermetic screw compressor. Both sides of the rotor casing 1 form a suction side end wall and a discharge side end wall, which are sealed by a suction casing and a discharge casing 3, and a male rotor tag and a female rotor 3 are engaged, and both rotors are connected to the discharge side of the casing l. It is in contact with the bicircular arc shape outer periphery on the side. When both rotors rotate in the direction of the arrow in the figure, they have the same lead, and the position where they engage gradually moves.The male rotor tag and male rotor Hiroshi, which engage with each other by providing thread grooves and threads with large leads on the outer periphery, are integrated. 6. Journal bearings whose shaft parts are respectively fitted into the discharge casing. (The journal bearing is not visible in the diagram)
and journal bearings g fitted into the discharge casing 3, respectively.
, 9 (journal bearings are not visible in the figure) bear the radial load, and the male rotor's shaft and the female rotor's inner rings are fitted into the motor frame. A nut into which the shaft part is fitted and screwed into each shaft part between it and the stepped part /41. /! Axial movement is restrained by r (symbols /, ?, 7.1 are not shown).

The integrated shaft of the male rotor is connected to the flexible drive shaft via the shaft coupling /4. is connected to. The opposite end of the flexible drive shirt (flexible drive shirt)/7 connected to the shaft joint 16 is connected to the hollow motor shaft /g by a spline.

The end of the suction casing is covered by a cover 79 fixed to the suction casing 2.

A suction passage is provided above the suction casing, and a suction port 21 is opened at a position continuous to the upper end surface between the male rotor and the female rotor S. A discharge port is provided on the end face of the discharge casing 3 opposite to the position where the male rotor S and the female rotor S meet below the suction port (not shown).

Two cylinders are fixed to the suction casing and its cover 19.

An unloader piston 23 sealed by a sealing ring is fitted into the cylinder 22, and the piston rod is sealed in a hole in the suction casing and extends into the rotor casing to change the suction side volume. It is fixed to a slide valve cog that adjusts the suction amount. , 20 is a balance piston that is rotatably fitted into the shaft of the male rotor tag, and whose outer diameter side is in close contact with the cylinder chamber Oa, and which balances the thrust with the male rotor tag by applying pressure oil to the cylinder chamber 20a. be.

A motor frame 5 is fixed to the discharge casing 3,
Motor frame, 2. An oil separation casing 2 is fixed to lt via a bearing plate 2A.

Motor frame! , 5-, a stator 29 is fixed within the motor frame 2! A rotor 3 is mounted on a motor shaft/1 supported by three bearings fitted into a partition wall 31 and a bearing plate 26.
3 is fixed.

The partition wall 31 and the bearing plate 2A are provided with openings of 0.7/a, 24a. An oil separator 31I is provided in the oil separation casing 27, and the oil separation casing 27 is provided with a delivery 33 and an oil outlet 3A for separated oil.

As is clear from the above, the screw compressor, motor, and oil separator are lined up in this order from the left in the figure and are integrally connected.

When the motor is energized, the motor shaft it rotates, causing the flexible drive shirt l-/7 to rotate.

And the female rotor engages when the male rotada is rotated via the shaft coupling 16! rotates in the opposite direction to the male rotada. As an example, these rotational speeds are 300'Or, p
, is rotated at high speed by an electric motor of about m.

When the female rotor y1 and the female rotor j rotate, gas is sucked from the suction port ko l through the piping (not shown) into the suction space constituted by the rotor casing 11 male rotor tag and the female rotor S, and from the compression space part, the gas is drawn into the male rotor tag and the female rotor. The outer periphery of each of the rotors S is in close contact with the inner periphery of the casing 1, and from the 7-pitch discharge side of these rotors, a compression space is created, and the gas gradually fills the volume between the male rotor, female rotor S, and casing 1. It is compressed by the reduction, is discharged from the discharge port, exits into the space between the discharge casing 3 and the partition wall 31 of the motor frame, passes through the opening 31a, and enters the motor. Then, it passes through the gap between the hestator cord and the rotor 33 and the passage between the stator 29 and the motor frame 23, passes through the opening 0.2A in the bearing plate B, and enters the oil separation casing core. , the refrigerant mixed with oil supplied to the screw compressor is passed through oil separator 3I.
The refrigerant is separated into refrigerant and oil by IJ, and the refrigerant is delivered to IJ s.
It exits from r and is sent to the process of the refrigeration cycle that continues.

The separated oil is collected at an oil outlet 36 and collected in an oil tank (not shown), cooled by a cooler, and sent to a screw compressor by an oil pump.

The above-mentioned conventional compressor of this type was constructed as shown in FIG. 1 and had the following drawbacks.

l Because it is horizontal, it is long in the axial direction and requires a large installation space.

Since the drive motor is located on the discharge side of the gas creme compressor, it is in an atmosphere of a mixture of refrigerant and a large amount of oil, and this mixture is at a high temperature of 60℃ to 1θO℃, so a structural design that increases the cooling effect is required. It will stop moving. Due to the large amount of oil and refrigerant contained in the discharged gas, the motor coil is susceptible to insulation failure, that is, softening, swelling, and melting due to heat, resulting in a shortened lifespan.

3. Because the compressor rotor casing is single-layered, the rotor meshing noise and rolling bearing noise are loud.

A separate oil tank is required to store the separated oil.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hermetic screw compressor that is small in size, requires a small installation space, does not heat up the motor, operates quietly, and does not require a separate oil tank.

The present invention is characterized in that a fully enclosed motor is disposed on the suction side of the screw compressor so that refrigerant is sucked through the motor, and the screw compressor is spaced apart from the casing of the screw compressor including the discharge side of the screw compressor. It has an outer casing that covers the machine, and the outer casing further has a delivery system, with the inside of the motor being a low-pressure chamber and the outside casing being a high-pressure chamber, and the motor inside the low-pressure chamber and the screw compressor inside the high-pressure chamber. be.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a longitudinal sectional view, and FIG. 3 is a longitudinal sectional view perpendicular to FIG.

The rotor casing, motor frame, and suction casing form an integrated casing lO, and the journal bearing 6. is fitted into the rotor casing part/a. The integrated shaft portion of the female rotor q1 and the female rotor S, which have mutually engaging threads formed on their outer peripheries, are supported by the journal bearings t and 9 fitted into the discharge casing 3 fixed to the rotor casing part/a. ing. Journal bearing f,? On the side there is a discharge casing 3 and a cover 37 fixed to the discharge casing 3.
A thrust bearing is engaged with the shaft of the male rotor and female rotor 5 to carry the thrust of both rotors.
/J is provided, and the shaft ends of these rotors are locked so as to carry the thrust of the male rotor tag and female rotor S.

A suction port 0.2/ of the screw compressor is bored in the partition wall between the rotor casing part /a and the motor frame part 3a. The outer casing 3g is sealed and fixed to the flange 39 at the boundary between the motor frame parts J, lta and the rotor casing part/a at a distance from the outer periphery of the rotor casing part/a, so that the rotor casing part/a is completely covered. ing.

The discharge casing 3 is provided with a discharge port L2, and the delivery 3! is the provision.

The lower part of the outer casing 3g has an oil reservoir ttti,
It communicates with the oil outlet 36 through the oil source octopus. Passages z and tb are provided at a plurality of locations between the inner periphery of the motor frame parts j and ta and the stator 29 in the motor axial direction. Motor frame part 25a of the casing! The fixed motor cover 4I3 has a refrigerant intake port pp.

The motor shaft 30 is integrated with the male rotor of the screw compressor, and only one side of the rotor 33 has a journal bearing 1.
1.

Although not shown, the journal bearing &, 'l, t, 9, thrust bearings i, i, i3, the engagement part of the male rotor and female rotor j, the male rotor, the female rotor! Sealing part on outer circumference and inner circumference of rotor casing part Ja, male rotor tag, female rotor! Oil is sent into the working space where the refrigerant gas is compressed for purposes such as cooling, lubrication, and sealing, and these oils are ultimately discharged from the screw compressor together with the refrigerant. be.

When the motor is energized, the motor shaft 30 rotates and the male rotor rotates in the opposite direction to the mating female rotor Sli. The refrigerant sucked from the refrigerant intake log is the motor cover 4t. Go inside, stator a and rotor 33
Gap between, passage between motor frame part Kota a and stator 29: 1. Passing through jt'0, the motor lower space lI!
to go into. Therefore, the stator 9 and the rotor 33 are cooled by low-temperature refrigerant gas from the surroundings. Lower space 4/! From there, the refrigerant sucked into the screw compressor through the suction 0.2/ is moved to the male rotor tag, and the space following the female rotor 3 engages the discharge side, where the refrigerant gas is compressed and transferred to the discharge casing 3.
The oil in the refrigerant supplied to the screw compressor is separated by the demister F/ from the discharge 0.22 discharged from the outer casing 3 to the inside of the outer casing 3 and passes through the demister 4// to the oil reservoir in the lower part of the outer casing 3t. Fall to Department QA. The oil in the oil reservoir lI6 is filtered by an oil source device 4'j, sucked out from an oil outlet 36 by an oil pump (not shown), cooled by an oil cooler (not shown), and sent to a screw compressor.

The oil-free refrigerant gas that has passed through the demister 4'/ is circulated from the delivery 35 through a necessary process in the refrigeration cycle to the refrigerant intake port VU of the motor cover t13. In the screw compressor, the thrust of the male rotor q acts upward against the gravity of the male rotor, motor rotor 33, motor shaft 30, etc. in the figure, and is supported by the thrust bearing 7.2.

The fpH diagram is another example of the invention. The first embodiment has a motor in the upper part and a screw compressor in the lower part, but this embodiment has a motor in the lower part and a screw compressor in the upper part.

A casing 10 in which a rotor casing part/a and a motor frame part 3a are integrated is fixed to a base duct. The structure inside the motor frame N'2ja is the same as the first embodiment turned upside down. The refrigerant intake port p<z is the motor frame part,
2. ta base 41-7, stator 29, rotor 3
Provided so that the space between 3 and the outside communicate with each other.

The configuration of the screw compressor is the same as in the first embodiment. The outer casing 3Ir is fixed to the flange 3de of the casing IO. The demister II/ is provided so as to partition the outer casing 3g between the screw compressor and the delivery I)ysl provided at the top of the outer casing 3g.

When the motor is energized, the screw compressor rotates, and the refrigerant that enters from the refrigerant intake port 1I is sent to the stator, 2q, and rotor 3.
Listen to the space between 3 and the passage λ, yb, and space G! The refrigerant is sucked into the screw compressor through the suction ports, t and i, is compressed, enters the outer casing 3g from the discharge port, the oil is separated in the demister Il, and the refrigerant is delivered to the delivery IJ,
? The oil is supplied to the refrigeration cycle from oil reservoir lI6.
The oil accumulates in the oil and is taken out from the oil outlet JA through the oil source octopus. Still other embodiments may be horizontal. That is, place it horizontally in the state shown in Figure 1, Figure 3, or Figure 9,
A delivery is provided in the upper part of the outer casing, the inside of the outer casing is partitioned off with a demister between the delivery and the discharge of the screw compressor, and the lower part of the outer casing is used as an oil reservoir and an oil filter and an oil outlet are provided.

The effects of the present invention are as described above: (1) Since the device is arranged vertically, the installation space is small, so multiple devices can be installed in parallel. Since the weight of the compressor rotor and the rotor of the drive motor in the radial direction is eliminated, the bearing load is reduced. Furthermore, since the shaft does not bend due to its own weight, the drive motor can be supported on one side. Cantilevering simplifies the oil supply system and reduces the number of bearings in front of the bearings. In the thrust direction, the rotor's own weight is applied when the rotor is stopped, but when the rotor is in operation, a thrust force acts in the direction opposite to its own weight, so the thrust load is reduced by the amount of the rotor's own weight, so the thrust bearing may be small. By arranging the discharge port of the discharge gas at a position lower than the oil separation element as in the first embodiment, it is possible to expect the effect of separating a large amount of oil in the discharge gas by gravity. Part of the oil contained in the suction port gas and the oil leaked from the suction side seal are introduced into the compression chamber without retention.

(2) Place the drive motor on the low pressure side of the screw compressor,
Since the refrigerant gas intake is located on the opposite side of the screw compressor, the drive motor is cooled with low-temperature suction gas during operation, resulting in a high cooling effect and stable operation as the suction gas temperature remains almost constant. can continue. And the motor can be made smaller. Since the suction gas contains almost no oil, deterioration in insulation due to oil and refrigerant can be prevented.

(3) The partition wall divides the low-pressure chamber and the high-pressure chamber into two, and since the suction gas is not heated by the high-temperature discharged gas, a decrease in volumetric efficiency can be suppressed.

(4) Since the high pressure chamber has a constant casing, it has the effect of reducing rotor meshing noise and rolling bearing noise. Oil can be stored at the bottom of the outer casing. It is possible to install an oil separation demister in the gap between the inner and outer casings. And since no shaft seal is required, there is no leakage of refrigerant. The outer casing is just a casing and is completely sealed. The compressor drive motor, oil separation device and oil reservoir unique to screw compressors are all integrated, making it smaller and lighter.

Furthermore, the above effects can also be achieved with a horizontal type. However, although the setting space is smaller than that of the conventional example, it is larger than that of the vertical embodiment of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional example, FIG. 2 is a longitudinal sectional view of an embodiment of the present invention, FIG. 3 is a longitudinal sectional view in a direction perpendicular to FIG. 1, and FIG. FIG. 3 is a longitudinal cross-sectional view of the embodiment. l-.Rotor casing /a..Rotor casing section K..Suction casing 2a..Rotor casing section 3..Discharge casing...Male rotor 3.ΦFemale rotor 6,7J,9..Journal bearing 10.. Casing /:l. 13-・Thrust bearing /l, 15・Rice nut/A-・
Shaft coupling: Flexible drive shaft /1
・・Motor shaft /9・・Cover 20−・Balance piston :l Q a@fist cylinder chamber 21・・Suction port
2...Discharge port 23 - Unloader piston 2'l-
-Slide valve 23...Motor frame, 2ta
・・Motor frame part ko, tb-φ passage, 2A・・
Bearing plate, 2Aa...Opening 27...Oil separation casing Co9...Stator 30111I Mootsu shaft 31...
Partition wall 3/a-” opening 3 pieces...Bearing 33I1110
-Ta 3'l...Oil sepa l. -Ta 35... Delivery 36... Oil outlet 37... Cover 3g - Outer casing 39... Flange g/...
・Demister tl, 2・・Oil filter lIJ・・Motor cover tl・・Intake lok S・・Lower space q6・Oil sump Guku・ψ base. Figure 1 Figure 2 Figure 3 Figure 4 Figure 7

Claims (1)

[Scope of Claims] l An oil separation element for oil contained in the refrigerant and an oil sump for oil used to supply oil to a separate screw compressor are provided in parallel within the casing, and the distance between the shafts is smaller than the diameter of the casing. A male rotor and a female rotor are provided in two cylindrical bores that overlap each other such that the diameter of the rotor is small, and are rotatably supported around the bore center and mesh with each other in turn. Both ends of the bore are provided with a suction side end wall and a discharge side end wall that are perpendicular to the bore axis, and the suction side end wall and the discharge side end wall have an end wall suction port and an end wall discharge port, respectively, and the male and female ports. In a screw compressor equipped with bearings that support the rotor shaft on the suction and discharge sides, the drive shaft of the screw compressor and the shaft of the fully enclosed motor are directly connected, and the drive shaft of the screw compressor is directly connected to the screw compressor through the inside of the motor. The inside of the motor is a low-pressure chamber so that the working fluid can be sucked in (1), and the screw compressor and motor frame are connected, and at least the screw compressor is connected to the outer casing at a distance from the casing of the screw compressor. A screw compressor with a sealed outer casing as a high-pressure chamber and a compressed working fluid delivered to the outer casing. The screw compressor according to claim 1, wherein the drive shaft and motor shaft of the screw compressor are arranged vertically so that the low pressure chamber and the high pressure chamber are arranged vertically. 3. The screw compressor according to claim 1, characterized in that the high pressure chamber is arranged in the upper part and the low pressure chamber is arranged in the lower part. The screw compressor according to claim 1, wherein the low pressure chamber is arranged at the upper part and the high pressure chamber is arranged at the lower part. Claims 1, 1, and 2, wherein an oil separation element is disposed in the outer casing between the discharge port of the screw compressor and the delivery of the outer casing, and the lower part of the outer casing is an oil reservoir.
The screw compressor according to any one of Items 3 and 9. Claims 1 to 5 are characterized in that the male rotor and the rotor of the motor are supported by a bearing disposed on the suction side of the drive shaft of the screw compressor and a bearing on the discharge side. A screw compressor of any one of the following. 7. Any one of claims 1 to 6, wherein the bearings that support the shafts of the male and female rotors of the screw compressor on the discharge side are provided with a thrust bearing in parallel with a radial bearing. Two screw compressors.