JP6760804B2 - Compressor - Google Patents

Description

The present invention relates to a compressor used for refrigeration and air conditioning.

A screw compressor, which is a type of compressor, is mainly composed of a screw rotor, a low-pressure side bearing and a high-pressure side bearing that support the screw rotor, an electric motor that drives the screw rotor, and a casing that houses them. The electric motor can be arranged on either the low pressure side or the high pressure side, but if it is arranged on the low pressure side, the electric motor generated by the low temperature or low pressure refrigerant gas can be cooled, so that the electric motor is often arranged on the low pressure side. Patent Document 1 discloses a screw compressor in which an electric motor for driving a screw rotor is arranged on the low pressure side.

In addition, there are not a few foreign substances such as copper powder and iron powder that could not be completely removed by washing before use in the refrigeration cycle. When the screw compressor, which is a component of the refrigeration cycle, sucks in the refrigerant gas containing these foreign substances, it damages the raceway surface and rolling surface of the bearing that supports the compression mechanism, and the bearing life is significantly shortened. May cause you to. In order to prevent the reliability of the screw compressor from being lowered due to the suction of foreign matter, it is common to equip the casing on the low pressure side with a strainer for removing foreign matter contained in the intake refrigerant gas.

On the other hand, if an electric motor or a strainer is arranged in the casing on the low pressure side, the gas passage area in the casing on the low pressure side is reduced and the suction pressure loss of the refrigerant gas is increased. As a result, the amount of refrigerant circulating decreases and the performance of the compressor deteriorates. Patent Document 2 discloses a screw compressor provided with a fixed flange for mounting a strainer in order to reduce suction pressure loss. In Patent Document 2, by installing a fixed flange for mounting the strainer, it is possible to freely set the passing area of the strainer, the passing area is expanded, and the suction pressure loss is reduced.

Japanese Unexamined Patent Publication No. 07-317684 JP-A-2007-303319

By the way, in addition to the electric motor and strainer arranged in the casing on the low pressure side, the accumulation of refrigerating machine oil in the casing on the low pressure side is a factor for reducing the suction pressure loss. That is, when the oil mixed in the discharged refrigerant gas is carried out from the compressor to the refrigeration cycle, the oil circulates in the refrigeration cycle and is sucked together with the refrigerant from the refrigerant suction port of the compressor, and this oil is sucked from the refrigerant suction port of the compressor. By accumulating in the space, the passage area of the refrigerant gas is reduced. As a result, the pressure loss of the refrigerant gas increased, and the performance of the compressor deteriorated.

Therefore, an object of the present invention is to provide a compressor capable of removing oil accumulated in the lower part of the casing, suppressing an increase in pressure loss of a refrigerant gas, and preventing deterioration of performance.

In order to achieve the above object, the compressor according to one embodiment of the present invention includes a casing having a refrigerant suction port, an electric motor housed in the casing, and a compressor housed in the casing and driven by the electric motor. The compression mechanism unit that compresses the refrigerant gas, the space located in the lower part of the casing on the gas flow path of the refrigerant gas from the refrigerant suction port to the compression mechanism unit, and the compressor mechanism are communicated with each other. An oil passage to be used and a decompression device provided in the middle of the oil passage for forming a decompression region in the oil passage are provided.

According to the present invention, it is possible to provide a compressor capable of removing oil accumulated in the lower part of the casing, suppressing an increase in pressure loss of a refrigerant gas, and preventing deterioration of performance.

The cross-sectional view of the screw compressor which concerns on 1st Embodiment of this invention is shown. The cross-sectional view of the compression mechanism part of a screw compressor is shown. The cross-sectional view of the screw compressor which concerns on 2nd Embodiment of this invention is shown.

Hereinafter, embodiments of the screw compressor of the present invention will be described with reference to the drawings. In each figure, the parts with the same reference numerals indicate the same or corresponding parts.

First, the screw compressor 100 according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 shows a cross-sectional view of the screw compressor 100 according to the first embodiment of the present invention, and FIG. 2 shows a cross-sectional view of a compression mechanism portion of the screw compressor 100.

The screw compressor 100 has a main casing 1, a motor casing 2 having a suction port 7, a discharge casing 3, and an oil separation casing 4 having a discharge port 13, and these casings 1 to 4 are connected to each other in a sealed relationship. ing.

The drive electric motor 6 is housed in the motor casing 2. The drive electric motor 6 includes an electric motor stator 6a fixed to the motor casing 2 and an electric motor rotor 6b rotatably provided in the electric motor stator 6a. The drive electric motor 6 is driven by a current supplied through the power supply terminal 20. Further, the motor casing 2 is formed with a refrigerant suction port 7 to which a strainer is attached.

The main casing 1 is formed with a cylindrical bore 15 and a suction port 8 for introducing gas into the cylindrical bore 15. As shown in FIG. 2, the male rotor 5a and the female rotor 5b are housed in the cylindrical bore 15 in a state of being meshed with each other. The compression chamber 30 is formed by the main casing 1 and the meshing tooth surfaces of the male rotor 5a and the female rotor 5b. Further, a suction port forming portion 8a is provided below the male rotor 5a and the female rotor 5b of the main casing 1. The suction port forming portion 8a has an inclined surface 8b that is inclined so as to approach the male rotor 5a and the female rotor 5b from the upstream side to the downstream side of the flow path of the refrigerant gas. The suction port 8 is formed by the inclined surface 8b. The compression mechanism portion is composed of the male rotor 5a, the female rotor 5b, and the like.

On the upstream side of the suction port forming portion 8a, a pre-suction oil collecting portion 33 in which the oil in the refrigerant gas is collected is generated. The pre-suction oil sump 33 is on the gas flow path of the refrigerant gas from the refrigerant suction port 7 to the compression mechanism, and corresponds to a space located at the lower part in the main casing 1. The oil in the refrigerant gas accumulates in the space and becomes the oil reservoir 33 before suction. The space is a recess formed by the main casing 1, other members, and the like.

As shown in FIG. 1, the suction side shaft portion of the male rotor 5a is rotatably supported by roller bearings 9 and 10 provided in the main casing 1, and the discharge side shaft portion of the male rotor 5a is rotatably supported by the discharge casing 3. It is rotatably supported by the roller bearings 11 and ball bearings 12 provided. The shaft of the male rotor 5a is connected to the motor rotor 6b of the drive motor 6 on the motor casing 2 side. The suction side shaft portion of the female rotor 5b is rotatably supported by a roller bearing (not shown) provided in the main casing 1, and the discharge side shaft portion of the female rotor 5b is supported by a roller bearing (not shown) provided in the discharge casing 3. It is rotatably supported by bearings and ball bearings.

Further, the main casing 1 is provided with an oil sump portion 18. The oil sump portion 18 is configured to collect the oil separated from the refrigerant gas by the oil separator provided in the oil separation casing 4. Further, the main casing 1 is formed with an oil passage 31 and a main side refrigerant gas passage 32a. The oil passage 31 is formed so as to connect the compression chamber 30 and the oil reservoir 33 before suction. One end of the oil passage 31 is connected to the lower part of the oil reservoir 33 before suction, and the other end is configured to communicate with the compression chamber 30 at the start of compression of the gas refrigerant. One end of the main refrigerant gas passage 32a is connected to the oil passage 31, and the other end is connected to the discharge side refrigerant gas passage 32b described later. An ejector mechanism 34 as a decompression device is provided at the connection portion between the oil passage 31 and the main side refrigerant gas passage 32a. The ejector mechanism 34 creates a depressurized state by utilizing the flow of the refrigerant gas.

The discharge casing 3 is fixed to the main casing 1 by bolts or the like. The roller bearing 11 and the ball bearing 12 are housed. The discharge casing 3 is formed with a gas discharge passage 14 that communicates the cylindrical bore 15 and the oil separation casing 4. Further, a shielding plate 17 for closing the bearing chamber 16 for accommodating the roller bearing 11 and the ball bearing 12 is attached to one end of the discharge casing 3. The discharge casing 3 is formed with a discharge-side refrigerant gas passage 32b, one end of which is connected to the other end of the main-side refrigerant gas passage 32a and the other end of which is connected to the discharge passage 14. The refrigerant gas passage 32 is configured by the main side refrigerant gas passage 32a and the discharge side refrigerant gas passage 32b.

Further, an oil supply passage (not shown) is formed in the main casing 1 and the discharge casing 3, and is configured to communicate the oil sump portion 18 at the lower part of the main casing 1 with each bearing.

Next, the flow of the refrigerant gas and the oil in the screw compressor 100 will be described.

The low-temperature, low-pressure refrigerant gas sucked from the refrigerant suction port 7 of the motor casing 2 fills the gas passage provided between the drive motor 6 and the motor casing 2, and the gap between the motor stator 6a and the motor rotor 6b. After passing through and cooling the drive motor 6, it passes through the suction side oil reservoir 33 and is compressed from the suction port 8 formed in the main casing 1 under the male rotor 5a and the female rotor 5b. Inhaled into chamber 30. After that, the refrigerant gas is sealed in the compression chamber 30, and is gradually compressed by the reduction of the compression chamber 30 accompanying the rotation of the male rotor 5a to become a high-temperature, high-pressure refrigerant gas, which is discharged from the discharge casing 3 to the discharge passage 14. Is discharged into the oil separation casing 4. Further, a part of the high-temperature and high-pressure refrigerant gas discharged to the discharge passage 14 flows into the refrigerant gas passage 32.

On the other hand, of the compression reaction forces acting on the male rotor 5a and the female rotor 5b during compression, the radial load is supported by the roller bearings 9, 10 and 11, and the thrust load is supported by the ball bearing 12. Oil for lubrication and cooling of these bearings is provided from an oil reservoir 18 provided on the high pressure side (downstream side of the refrigerant gas with respect to the compression chamber 30) of the main casing 1 through an oil supply passage communicating with each bearing by a differential pressure. Oil is supplied to each bearing through the bearing, and the compressed gas is discharged into the oil separation casing 4. The oil contained in the compressed refrigerant gas is separated from the refrigerant gas by the oil separator in the oil separation casing 4, and is stored in the oil reservoir 18 provided in the main casing 1. After the oil is separated, the compressed refrigerant gas is discharged from the refrigerant discharge port 13.

Further, in the vicinity of the suction port 8 of the main casing 1, the oil mixed in the refrigerant gas sucked from the refrigerant suction port 7 is accumulated, so that the suction side oil pool portion 33 is generated. A decompression region is generated in the ejector mechanism 34 by the refrigerant gas flowing into the refrigerant gas passage 32. Since the ejector mechanism 34 is provided in the middle of the oil passage 31, the oil in the suction side oil reservoir 33 is sucked. The sucked oil is carried to the compression chamber 30, compressed together with the refrigerant gas, and finally stored in the oil reservoir 18 of the main casing 1.

According to the screw compressor 100 as described above, the oil in the suction side oil reservoir 33 is carried to the compression chamber 30 by the ejector mechanism 34 via the oil passage 31, and is separated from the refrigerant gas by the oil separation casing 4. After that, it is stored in the oil reservoir 18. In this way, the oil accumulated in the suction side oil reservoir 33 can be discharged. As a result, it is possible to prevent a decrease in the passage area of the gas refrigerant on the upstream side of the suction port 8 and reduce the pressure loss. Therefore, it is possible to prevent the performance of the screw compressor 100 from deteriorating.

Further, since the decompression device is an ejector mechanism 34, a decompression region can be generated by a simple configuration, and the oil in the suction side oil reservoir 33 can be carried to the compression chamber 30.

Further, since the oil passage 31 is formed in the main casing 1, the size of the screw compressor 100 can be made compact.

Further, since the oil passage 31 is configured to communicate with the compression chamber 30 at the start of compression of the gas refrigerant (immediately after sealing), the differential pressure between the compression chamber 30 and the discharge passage 14 can be increased. The oil discharge effect can be improved.

Further, since the oil passage 31 is connected to the lower part of the suction side oil sump portion 33, the oil accumulated in the suction side oil sump portion 33 can be sufficiently discharged.

Next, the screw compressor 200 according to the second embodiment of the present invention will be described with reference to FIG. The same members as those of the screw compressor 100 according to the first embodiment are designated by the same reference numbers, the description thereof will be omitted, and the different parts will be described.

FIG. 3 shows a cross-sectional view of the screw compressor 200 according to the second embodiment.

As shown in FIG. 3, an oil passage for discharging oil from the pre-suction oil reservoir 33 is composed of an oil pipe 35 and a casing oil passage 36. The oil pipe 35 is provided outside the main casing 1, one end of which is connected to the lower part of the suction side oil reservoir 33, and the other end of which is connected to the end surface of the main casing 1. The casing oil passage 36 is formed in the main casing 1, one end of which is connected to the other end of the oil pipe 35, and the other end of which is connected to the compression chamber 30 (FIG. 2).

Further, the refrigerant gas pipe 37 is provided outside the main casing 1 and the discharge casing 3, one end of which is connected to the refrigerant discharge port 13 of the oil separation casing 4, and the other end of which is connected to the oil pipe 35. An ejector mechanism 34 is provided at the connection portion between the oil pipe 35 and the refrigerant gas pipe 37.

Even in this configuration, the oil in the suction side oil reservoir 33 is carried to the compression chamber 30 by the ejector mechanism 34 via the oil pipe 35 and the casing oil passage 36, and is separated from the refrigerant gas by the oil separation casing 4. , It is stored in the oil reservoir 18.

Therefore, according to the screw compressor 200 of the present embodiment, the oil accumulated in the suction side oil reservoir 33 can be discharged as in the screw compressor 100 of the first embodiment, so that the suction port 8 can be used. It is possible to prevent a decrease in the passage area of the gas refrigerant on the upstream side, and it is possible to reduce the pressure loss. Therefore, it is possible to prevent the performance of the screw compressor 200 from deteriorating.

Further, since the oil passage is composed of the oil pipe 35 provided outside the main casing 1, the main casing 1 can be simplified. Further, since the ejector mechanism 34 and the refrigerant gas pipe 37 are also provided outside the main casing 1 and the discharge casing 3, the main casing 1 and the discharge casing 3 can be simplified.

The present invention is not limited to the above-described examples, and includes various modifications.
For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations.

For example, in the above embodiment, the ejector mechanism 34 is used as the decompression device, but a pump may be used. Further, in the above embodiment, the oil passage 31 is configured to communicate with the compression chamber 30 at the start of compression of the gas refrigerant, but the volume ratio at the start of compression to the middle of compression is 1 to 1.5. It may be configured to communicate with a certain compression chamber 30. If the timing for returning the oil is before the start of compression (volume ratio is 1 or less), the oil leaks to the low pressure side to warm the refrigerant gas, the refrigerant gas expands, and the refrigerant gas may not be sufficiently compressed in the compression chamber 30. There is sex. On the other hand, when the volume ratio is larger than 1.5, the differential pressure between the compression chamber 30 and the discharge passage 14 cannot be sufficiently taken, and the oil in the suction side oil reservoir 33 cannot be sufficiently discharged.

Further, although the above embodiment has described the case where the present invention is applied to a screw compressor for refrigeration and air conditioning, other gas compressors such as a rotary type, a scroll type, and a reciprocating compressor, as well as oil on the suction side. The same applies to any compressor in which a puddle is generated. Further, although one end of the refrigerant gas pipe 37 is connected to the refrigerant discharge port 13 of the oil separation casing 4, it may be connected to the discharge passage 14.

1 Main casing 2 Motor casing 3 Discharge casing 4 Oil separation casing 5a Male rotor 5b Female rotor 6 Drive motor 6a Electric motor stator 6b Motor rotor 7 Refrigerator suction port 8 Suction port 8a Suction port forming part 8b Inclined surface 9 Roller bearing 10 Roller bearing 11 Roller bearing 12 Ball bearing 13 Refrigerator discharge port 14 Refrigerator gas discharge passage 15 Cylindrical bore 16 Bearing chamber 17 Shielding plate 18 Oil reservoir 20 Power supply terminal 30 Compressor 31 Oil passage 32 Refrigerator gas passage
32a Main side refrigerant gas passage 32b Discharge side refrigerant gas passage 33 Suction side oil reservoir 34 Ejector mechanism 35 Oil pipe 36 Casing oil passage 37 Refrigerant gas pipe

Claims (6)

A casing with a refrigerant suction port and
The electric motor housed in the casing and
A compression mechanism unit housed in the casing, driven by the electric motor, and compressing the refrigerant gas.
An oil passage on the gas flow path of the refrigerant gas from the refrigerant suction port to the compression mechanism portion, which communicates with the space located at the lower part in the casing and the compression mechanism portion.
A decompression device provided in the middle of the oil passage and for forming a decompression region in the oil passage is provided .
The compression mechanism has a male rotor and a female rotor that mesh with each other.
A compression chamber for compressing the gas refrigerant is formed by the casing and the meshing tooth surfaces of the male rotor and the female rotor.
The oil passage communicates the space with the compression chamber.
The decompressor, the compressor Ru ejector mechanism der to form a region of reduced pressure by using a flow of high-pressure gas refrigerant discharged from the compression chamber. The compressor according to claim 1 , wherein the oil passage is formed in the casing. The oil passage is formed in an oil pipe provided outside the casing and one end connected to the space, and one end connected to the other end of the oil pipe and the other end connected to the compression chamber. Consists of a casing passage and
The compressor according to claim 1 or 2 , wherein the ejector mechanism is provided in the oil pipe. The compressor according to any one of claims 1 to 3, wherein the oil passage is configured to communicate with the compression chamber at the start of compression of the gas refrigerant. The oil passage is configured to communicate with the compression chamber in which the volume ratio at the start of compression to the middle of compression is 1 to 1.5, according to any one of claims 1 to 3. Described compressor. The space is an oil sump where oil in the refrigerant gas is collected.
The compressor according to any one of claims 1 to 5 , wherein the oil passage is connected to the lower part of the oil sump.

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