JP2017025790A - Compressor including sliding bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect that a lubrication layer wears, and suppress the generation of fragments and powder derived from a base material.SOLUTION: A compressor includes a motor, a shaft, a fluid compression mechanism, and a sliding bearing 40. The shaft is rotated around a rotary shaft by the motor. The fluid compression mechanism is driven by the shaft. The sliding bearing 40 journals the shaft. The sliding bearing 40 has a first lubrication layer 41, a second lubrication layer 42, and a base material 43. The first lubrication layer 41 having a first friction coefficient contacts the shaft. The second lubrication layer 42 having a second friction coefficient greater than the first friction coefficient is further isolated from the rotary shaft than the first lubrication layer 41. The base material 43 is further isolated from the rotary shaft than the second lubrication layer 42.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a compressor including a slide bearing.

  A compressor is used in the refrigeration system. In the pressure vessel of the compressor, a motor, a fluid compression mechanism, and a shaft for transmitting the power of the motor to the fluid compression mechanism are installed. As shown in Patent Document 1 (Japanese Patent Application Laid-Open No. 2011-1854), this shaft may be supported by a slide bearing.

  The slide bearing has, for example, a metal base material having a cylindrical shape, and a lubricating layer disposed inside the base material. The lubricating layer is made of a material having a small friction coefficient. The shaft is placed in contact with the lubricating layer. When the shaft rotates during operation of the compressor, the shaft slides with the lubricating layer.

  If the compressor is used for many years, the lubricating layer will wear out. When the lubricating layer disappears due to wear, the shaft slides with the exposed base material. As a result, metal fragments and powder are generated from the base material. Debris and powder circulate in the refrigerant circuit and adversely affect parts installed in the refrigerant circuit.

  An object of the present invention is to detect that the lubricating layer has been worn to some extent and to suppress generation of debris and powder derived from the base material.

  A compressor according to a first aspect of the present invention includes a motor, a shaft, a fluid compression mechanism, and a slide bearing. The shaft is rotated around the rotation axis by a motor. The fluid compression mechanism is driven by the shaft. The plain bearing supports the shaft. The plain bearing has a first lubricating layer, a second lubricating layer, and a base material. The first lubricating layer has a first coefficient of friction and contacts the shaft. The second lubrication layer has a second friction coefficient larger than the first friction coefficient, and is separated from the rotation shaft than the first lubrication layer. The base material is further away from the rotation shaft than the second lubricating layer.

  According to this configuration, when the first lubricating layer disappears by sliding with the shaft and the second lubricating layer is exposed, the operation of the compressor can be stopped. Therefore, since the base material is not exposed, it is possible to suppress the occurrence of a situation in which debris or powder derived from the base material goes out of the compressor and circulates through the refrigerant circuit.

  The compressor which concerns on the 2nd viewpoint of this invention is a compressor which concerns on a 1st viewpoint. WHEREIN: A 2nd friction coefficient is 2 times or more of a 1st friction coefficient.

  According to this configuration, when the first lubricating layer disappears, the shaft slides with the second lubricating layer, and the frictional resistance of the shaft increases. Therefore, the disappearance of the first lubricating layer can be detected by the increase in the frictional resistance.

  The compressor which concerns on the 3rd viewpoint of this invention is a compressor which concerns on a 2nd viewpoint. WHEREIN: A 2nd friction coefficient is 3 times or more of a 1st friction coefficient.

  According to this configuration, the increase in the frictional resistance of the shaft when the first lubricating layer disappears becomes larger. Therefore, it becomes easier to detect the disappearance of the first lubricating layer 41.

  A compressor according to a fourth aspect of the present invention is the compressor according to any one of the first to third aspects, wherein the first lubricating layer and the second lubricating layer are both a porous material and a porous material. It has a resin impregnated in the material.

  According to this configuration, the first lubricating layer and the second lubricating layer have a property that they are not easily worn even when sliding with the shaft due to the presence of the resin. Therefore, it is possible to suppress the worn debris and powder from adversely affecting the refrigerant circuit.

  A compressor according to a fifth aspect of the present invention is the compressor according to the fourth aspect, wherein the porous material is a sintered body of metal powder.

  According to this configuration, the porous material is formed by sintering metal powder. Therefore, the first lubricating layer and the second lubricating layer have durability due to the presence of the sintered body having a certain strength.

  In the compressor according to the sixth aspect of the present invention, in the compressor according to any one of the first to fifth aspects, the first lubricating layer has a thickness of 50 μm or more and 100 μm or less.

  According to this configuration, the first lubricating layer has a thickness of 50 μm or more and 100 μm or less. Therefore, it can be expected that the first lubricating layer will be durable until the time when each component of the compressor is likely to deteriorate.

  In the compressor according to the seventh aspect of the present invention, in the compressor according to any one of the first aspect to the sixth aspect, the second lubricating layer has a thickness of 150 μm or more.

  According to this configuration, the second lubricating layer has a thickness of 150 μm or more. Therefore, since the 2nd lubricating layer is thick, the situation where a shaft slides with a base material can be controlled more.

  A refrigeration system according to an eighth aspect of the present invention includes a compressor, a decompressor, a heat source side heat exchanger, a use side heat exchanger, and a control unit. The compressor relates to any one of the first to seventh aspects. The control unit controls the compressor and the decompressor. The control unit includes a thickness detection unit, a normal range storage unit, and a wear determination unit. The thickness detection unit outputs a thickness signal corresponding to the thickness of the first lubricating layer. The normal range storage unit stores a normal range of the thickness signal. The wear determination unit determines whether the thickness signal is within or outside the normal range.

  According to this configuration, the control unit makes the wear loss determination by comparing the thickness signal related to the first lubricating layer with the predetermined normal range. Therefore, control for stopping the operation of the compressor can be performed according to the determination result.

  A refrigeration system according to a ninth aspect of the present invention further includes a current detection unit in the refrigeration system according to the eighth aspect. The current detection unit detects the value of the current flowing through the motor. The thickness signal is calculated based on the current value.

  According to this configuration, the degree of wear of the first lubricating layer can be known by monitoring the current value. Therefore, wear loss determination is easy.

  A refrigeration system according to a tenth aspect of the present invention is the refrigeration system according to the ninth aspect, wherein the control unit further includes a rotation speed detection unit and a reference data storage unit. The rotation speed detection unit detects the rotation speed of the shaft. The reference data storage unit stores current values as reference data for various rotational speeds of the shaft during operation of the refrigeration system over a certain period. The thickness signal is calculated based on the current value corrected using the rotation speed and the reference data.

  According to this configuration, the thickness signal based on the corrected current value is used for the wear loss determination. Therefore, the influence of the increase / decrease of the current value caused by the fluctuation of the rotation speed of the shaft can be eliminated, and thereby the accuracy of wear disappearance determination can be improved.

  According to the compressor concerning the 1st viewpoint of the present invention, generation | occurrence | production of the situation where the fragment or powder of a base material circulates through a refrigerant circuit can be suppressed.

  According to the refrigeration system according to the eighth aspect of the present invention, it is possible to perform control for stopping the operation of the compressor according to the determination result as to whether or not the first lubricating layer is worn.

Sectional drawing of the compressor 100 which concerns on 1st Embodiment of this invention. The perspective view of the sliding bearing 40 mounted in the compressor 100. FIG. The schematic diagram which shows the 1st process of manufacture of the slide bearing 40. FIG. The schematic diagram which shows the 2nd process of manufacture of the slide bearing 40. FIG. The schematic diagram which shows the 3rd process of manufacture of the slide bearing 40. FIG. The schematic diagram which shows the 4th process of manufacture of the slide bearing 40. FIG. The refrigerant circuit figure at the time of cold utilization of the refrigerating system 200 concerning 2nd Embodiment of this invention. The block diagram of the control part 290 mounted in the refrigeration system 200. FIG. The refrigerant circuit figure at the time of heat utilization of the refrigerating system 200. FIG.

<First Embodiment>
(1) Overall Configuration FIG. 1 shows a compressor 100 according to the present invention. The compressor 100 has a scroll type structure, and compresses and discharges the sucked fluid. The compressor 100 includes a pressure vessel 10, a motor 20, a shaft 30, a slide bearing 40, a fluid compression mechanism 50, a suction pipe 61, and a discharge pipe 62.

(2) Detailed configuration (2-1) Pressure vessel 10
The pressure vessel 10 is a vessel having a strength that can withstand the high pressure of the fluid filled therein, and includes a body portion 11, a lid portion 12, and a bottom portion 13. Inside the pressure vessel 10, a motor 20, a shaft 30, a slide bearing 40, and a fluid compression mechanism 50 are provided. A lubricating oil reservoir 14 is provided at the lower portion of the pressure vessel 10. Lubricating oil stored in the lubricating oil reservoir 14 is supplied to the sliding portion inside the compressor 100 by a pump mechanism (not shown), etc., lubricates the sliding portion, and then returns to the lubricating oil reservoir 14 again. .

(2-2) Motor 20
The motor 20 has a stator 21 and a rotor 22. The stator 21 has a cylindrical shape, and the outer peripheral side thereof is fixed to the pressure vessel 10. The rotor 22 is rotatably installed on the inner peripheral side of the stator 21. Due to the electromagnetic interaction between the stator 21 and the rotor 22, the rotor 22 rotates about the rotation axis A.

(2-3) Shaft 30
The shaft 30 is for transmitting the power generated by the motor 20 to the fluid compression mechanism 50. The shaft 30 is fixed to the rotor 22 and rotates around the rotation axis A together with the rotor 22. An eccentric portion 31 is formed on the shaft 30.

(2-4) Slide bearing 40
The slide bearing 40 is for supporting the shaft 30 and is provided, for example, at three locations. When the shaft 30 rotates, the shaft 30 slides on the slide bearing 40 through the lubricating oil.

  FIG. 2 shows a plain bearing 40. The plain bearing 40 has a cylindrical shape and includes a first lubricating layer 41, a second lubricating layer 42, and a base material 43. The first lubricating layer 41 is laminated on the second lubricating layer 42 and has a thickness of, for example, 50 μm or more and 100 μm or less. The second lubricating layer 42 is laminated on the base material 43, and has a thickness of, for example, 150 μm or more and 200 μm or less. The base material 43 is typically made of metal.

  The friction coefficient of the second lubricating layer 42 is larger than the friction coefficient of the first lubricating layer 41. The friction coefficient of a certain material here is a value when the material slides with the shaft 30 through the lubricating oil. For example, the friction coefficient of the second lubricating layer 42 is at least twice that of the first lubricating layer 41. Preferably, the friction coefficient of the second lubricating layer 42 is three times or more that of the first lubricating layer 41.

  3A to 3D show a method for manufacturing the slide bearing 40. In the first step shown in FIG. 3A, a metal powder M made of bronze, for example, is disposed on the base material 43. Next, in the second step shown in FIG. 3B, the metal powder M is heated together with the base material 43 to sinter the metal powder M, thereby forming the porous material P. In the third step shown in FIG. 3C, the material resin of the second lubricating layer is impregnated into the porous material P and cured to form the second lubricating layer 42. In the fourth step shown in FIG. 3D, the material resin of the first lubricating layer is impregnated into the porous material P and cured to form the first lubricating layer 41. Finally, the product of the fourth step is bent to form a cylindrical shape after the thickness is adjusted by cutting. The slide bearing 40 is manufactured by the above process.

(2-5) Fluid compression mechanism 50
Returning to FIG. 1, the fluid compression mechanism 50 is for compressing the fluid using the power transmitted by the shaft 30. The fluid compression mechanism 50 includes a fixed scroll 51 fixed to the pressure vessel 10 and a movable scroll 52 installed in the eccentric portion 31. A compression chamber 53 is defined by the fixed scroll 51 and the movable scroll 52. When the movable scroll 52 performs an eccentric motion by the rotation of the shaft 30, the volume of the compression chamber 53 varies.

(2-6) Suction pipe 61
The suction pipe 61 functions as a passage for taking in the fluid to be compressed from the outside of the pressure vessel 10 into the inside.

(2-7) Discharge pipe 62
The suction pipe 61 functions as a passage for sending out the high-pressure fluid discharged from the fluid compression mechanism 50 from the inside of the pressure vessel 10 to the outside.

(3) Basic operation The compressor 100 compresses the fluid in the following manner.

  The fluid outside the pressure vessel 10 is taken into the pressure vessel 10 through the suction pipe 61 and enters the compression chamber 53. As the volume of the compression chamber 53 is reduced, the low-pressure fluid in the compression chamber 53 is compressed and becomes high-pressure fluid. The high-pressure fluid passes through a discharge valve (not shown) provided in the movable scroll 52 and then goes out of the pressure vessel 10 through the discharge pipe 62.

(4) Wear Detection Operation When the compressor 100 is used for a long period of time, the first lubricating layer 41 is gradually worn by sliding with the shaft 30. Finally, since the first lubricating layer 41 disappears and the second lubricating layer 42 is exposed, the shaft 30 slides with the second lubricating layer 42. Since the friction coefficient of the second lubricating layer 42 is larger than the friction coefficient of the first lubricating layer 41, the frictional resistance that the shaft 30 receives is larger than that before the disappearance of the first lubricating layer 41. By detecting this change in frictional resistance, it can be detected that the first lubricating layer 41 has disappeared due to wear.

  The frictional resistance is observed, for example, by monitoring the magnitude of the current flowing through the motor 20 of the compressor 100. A thickness signal corresponding to the thickness of the first lubricating layer 41 is calculated based on the current value. When the thickness value indicated by the thickness signal is out of the predetermined range, it is determined that the first lubricating layer 41 has disappeared. In response to the disappearance of the first lubricating layer 41, control for forcibly stopping the operation of the compressor 100 is performed.

(5) Features (5-1)
When the first lubricating layer 41 disappears by sliding with the shaft 30 and the second lubricating layer 42 is exposed, the operation of the compressor 100 can be stopped. Therefore, since the base material 43 is not exposed, it is possible to suppress the occurrence of a situation in which debris or powder derived from the base material 43 goes out of the compressor 100 and circulates through the refrigerant circuit.

(5-2)
As described above, the friction coefficient of the second lubricating layer 42 can be set to be twice or more the friction coefficient of the first lubricating layer 41. In this case, when the first lubricating layer 41 disappears, the shaft 30 slides with the second lubricating layer 42, and the frictional resistance of the shaft 30 increases. Therefore, the disappearance of the first lubricating layer 41 can be detected by the increase in the frictional resistance.

(5-3)
As described above, the friction coefficient of the second lubricating layer 42 can be three times or more the friction coefficient of the first lubricating layer 41. In this case, the increase in the frictional resistance of the shaft 30 when the first lubricating layer 41 disappears becomes larger. Therefore, it becomes easier to detect the disappearance of the first lubricating layer 41.

(5-4)
The first lubrication layer 41 and the second lubrication layer 42 have the property that they are not easily worn by sliding with the shaft 30 due to the presence of the resin. Therefore, it is possible to suppress the worn debris and powder from adversely affecting the refrigerant circuit.

(5-5)
The porous material P is produced by sintering metal powder M. Accordingly, the first lubricating layer 41 and the second lubricating layer 42 have durability due to the presence of the sintered body having a certain strength.

(5-6)
The first lubricating layer 41 has a thickness of 50 μm or more and 100 μm or less. Therefore, it can be expected that the first lubricating layer 41 is durable until the time when the components of the compressor 100 are likely to deteriorate.

(5-7)
The second lubricating layer 42 has a thickness of 150 μm or more. Therefore, since the 2nd lubricating layer 42 is thick, the situation where the shaft 30 slides with the base material 43 can be suppressed more.

(6) Modifications (6-1) Shape of the slide bearing 40 The above-described slide bearing 40 is composed of a single member having a cylindrical shape. Instead of this, the plain bearing 40 may be composed of a single member or a plurality of members having an arc shape. According to this configuration, the shaft 30 and the slide bearing 40 can be easily installed in the manufacture of the compressor 100.

(6-2) Material of the first lubricating layer 41 and the second lubricating layer 42 The first lubricating layer 41 and the second lubricating layer 42 described above have the porous material P made by sintering the metal powder M. ing. Instead, at least one of the first lubricating layer 41 and the second lubricating layer 42 may have a porous material made by sintering carbon powder. According to this configuration, the sliding bearing 40 may be manufactured at a lower cost than when the metal powder M is used.

  Or at least one of the 1st lubricating layer 41 and the 2nd lubricating layer 42 may be comprised from the homogeneous raw material which does not have a porous material. According to this structure, manufacture of the slide bearing 40 becomes easier.

(6-3) Presence / absence of lubricating oil The compressor 100 does not have the lubricating oil reservoir 14, and the lubricating oil may not be used. In this case, the coefficient of friction of a specific material in the above discussion means a value when the material slides with the shaft 30 without lubricating oil.

Second Embodiment
(1) Overall Configuration FIG. 4 shows a refrigerant circuit of the refrigeration system 200 according to the present invention. The refrigeration system 200 includes a communication pipe 210, a heat source unit 240, and a utilization unit 250.

(2) Detailed configuration (2-1) Connection piping 210
The communication pipe 210 is for transferring fluid refrigerant between the heat source unit 240 and the utilization unit 250. The communication pipe 210 has a gas communication pipe 211 used for exchange of gas refrigerant and a liquid communication pipe 212 used for exchange of liquid refrigerant.

(2-2) Heat source unit 240
The heat source unit 240 is a device that generates cold or warm heat, and includes the compressor 100, a four-way switching valve 241, a heat source side heat exchanger 242, a heat source side pressure reducer 243, and an accumulator 244.

(2-2-1) Four-way selector valve 241
The four-way switching valve 241 is for switching the operation mode of the heat source unit 240. When the four-way switching valve 241 connects a pipe as indicated by a solid line in the figure, the heat source unit 240 is in a mode of operating as a cold heat source. On the other hand, when the four-way switching valve 241 connects the piping as indicated by the broken line in the drawing, the heat source unit 240 is in a mode of operating as a heat source.

(2-2-2) Compressor 100
The compressor 100 has been described above as the first embodiment. That is, the plain bearing 40 mounted on the compressor 100 includes a first lubricating layer 41, a second lubricating layer 42, and a base material 43, as shown in FIG.

(2-2-3) Heat source side heat exchanger 242
Returning to FIG. 4, the heat source side heat exchanger 242 performs heat exchange between the refrigerant and the air. When the heat source unit 240 operates as a cold heat source, the heat source side heat exchanger 242 operates as a condenser. On the other hand, when the heat source unit 240 operates as a heat source, the heat source side heat exchanger 242 operates as an evaporator.

(2-2-4) Heat source side decompressor 243
The heat-source-side decompressor 243 is for decompressing the refrigerant, and includes an expansion valve capable of adjusting the opening. When the heat source unit 240 operates as a cold heat source, the heat source side decompressor 243 is fully opened, and the decompression operation of the refrigerant is not performed. On the other hand, when the heat source unit 240 operates as a heat source, the opening degree of the heat source side decompressor 243 is appropriately reduced to decompress the circulating refrigerant.

(2-2-5) Accumulator 244
The accumulator 244 separates the refrigerant in a gas-liquid two-phase state into a gas refrigerant and a liquid refrigerant. The accumulator 244 allows the gas refrigerant to reach the compressor 100 while allowing the liquid refrigerant to remain in its housing.

(2-3) Usage unit 250
The utilization unit 250 is a device that makes use of the cold or warm heat generated by the heat source unit 240 for the user, and includes a utilization side heat exchanger 251 and a utilization side decompressor 252.

(2-3-1) Use side heat exchanger 251
The use side heat exchanger 251 performs heat exchange between the refrigerant and the air. When the heat source unit 240 operates as a cold heat source, the use side heat exchanger 251 operates as an evaporator. On the other hand, when the heat source unit 240 operates as a heat source, the use side heat exchanger 251 operates as a condenser.

(2-3-2) User-side decompressor 252
The use-side decompressor 252 is for decompressing the refrigerant, and includes an expansion valve capable of adjusting the opening degree. When the heat source unit 240 operates as a heat source, the use-side decompressor 252 is fully opened and the refrigerant decompression operation is not performed. On the other hand, when the heat source unit 240 operates as a cold heat source, the opening of the use-side decompressor 252 is appropriately throttled to decompress the circulating refrigerant.

(2-4) Control unit 290
FIG. 5 shows the control unit 290 of the refrigeration system 200. The control unit 290 controls a sensor for monitoring the operation state of each unit and an actuator for driving each unit, and performs various calculations.

  The control unit 290 includes a central processing unit 291, an operation panel 292, an actuator driving unit 293, a motor current detection unit 294, a motor rotation speed detection unit 295, a thickness detection unit 296, a reference data storage unit 297, a normal range storage unit 298, and A wear determination unit 299 is provided. The physical mounting positions of these portions are not particularly limited, that is, either of the utilization unit 250 and the heat source unit 240 may be used, or may be other than that.

(2-4-1) Central processing unit 291
The central processing unit 291 supervises the processing of each unit.

(2-4-2) Operation panel 292
The operation panel 292 is for inputting various settings.

(2-4-3) Actuator drive unit 293
The actuator driving unit 293 is for driving various actuators. The driving target includes the motor 20 of the compressor 100, the four-way switching valve 241, the heat source side pressure reducing device 243, the use side pressure reducing device 252, and the like.

(2-4-4) Motor current detection unit 294
The motor current detection unit 294 detects the magnitude of the current flowing through the motor 20 of the compressor 100.

(2-4-5) Motor rotation speed detector 295
The motor rotation speed detector 295 is connected to the encoder 23 of the motor 20 and detects the rotation speed of the rotor 22 or the shaft 30.

(2-4-6) Thickness detector 296
The thickness detector 296 estimates the thickness of the first lubricating layer 41 from the current value output from the motor current detector 294 and the rotational speed output from the motor rotational speed detector 295 by calculation, and a thickness signal indicating the thickness. Is output.

(2-4-7) Reference data storage unit 297
The reference data storage unit 297 stores all operating conditions of the compressor and the current magnitude of the motor 20 associated therewith as reference data.

(2-4-8) Normal range storage unit 298
The normal range storage unit 298 stores a value that defines a normal range of the thickness of the first lubricating layer 41 that is desirable when the compressor 100 is operated.

(2-4-9) Wear determination unit 299
The wear determination unit 299 compares the thickness signal output from the thickness detection unit 296 with the normal range stored in the normal range storage unit 298, so that the operation of the compressor 100 should be stopped. It is determined whether or not wear has occurred.

(3) Basic operation (3-1) Cold energy utilization operation When a user utilizes cold energy, the four-way switching valve 241 performs the connection indicated by the solid line in FIG. The refrigerant circulates in the direction of the arrow shown in FIG.

  In the heat source unit 240, the high-pressure gas refrigerant discharged from the compressor 100 goes to the heat source side heat exchanger 242 via the four-way switching valve 241. In the heat source side heat exchanger 242 functioning as a condenser, the high-pressure gas refrigerant releases heat into the air and becomes high-pressure liquid refrigerant. The high-pressure liquid refrigerant passes through the fully open heat source side pressure reducer 243, exits the heat source unit 240, passes through the liquid communication pipe 212, and reaches the use side pressure reducer 252 in the use unit 250. The use-side decompressor 252 having the adjusted throttle opening decompresses the high-pressure liquid refrigerant and releases the low-pressure gas-liquid two-phase refrigerant. In the use-side heat exchanger 251 that functions as an evaporator, the low-pressure gas-liquid two-phase refrigerant becomes a low-pressure gas refrigerant while absorbing heat from the air and providing cold heat to the user. The low-pressure gas refrigerant exits from the utilization unit 250 and enters the heat source unit 240 through the gas communication pipe 211. Thereafter, the low-pressure gas refrigerant goes to the accumulator 244 via the four-way switching valve 241. The accumulator 244 holds the liquid refrigerant that remains slightly in the low-pressure gas refrigerant, and directs only the gas refrigerant to the compressor 100.

(3-2) Operation using heat When the user uses heat, the four-way switching valve 241 performs the connection indicated by the broken line in FIG. As a result, the refrigerant circuit of the refrigeration system 200 is as shown in FIG. The refrigerant circulates in the direction of the arrow shown in FIG.

  In the heat source unit 240, the high-pressure gas refrigerant discharged from the compressor 100 exits the heat source unit 240 through the four-way switching valve 241, passes through the gas connection pipe 211, and is used in the usage unit 250. The heat exchanger 251 is reached. In the use-side heat exchanger 251 that functions as a condenser, the high-pressure gas refrigerant becomes a high-pressure liquid refrigerant while releasing heat to the air to provide heat to the user. The high-pressure liquid refrigerant passes through the fully-open use side pressure reducer 252, exits from the use unit 250, passes through the liquid communication pipe 212, and reaches the heat source side pressure reducer 243 in the heat source unit 240. The heat source side decompressor 243 having an adjusted throttle opening decompresses the high-pressure liquid refrigerant and releases the low-pressure gas-liquid two-phase refrigerant. In the heat source side heat exchanger 242 functioning as an evaporator, the low-pressure gas-liquid two-phase refrigerant absorbs heat from the air and becomes a low-pressure gas refrigerant. The low-pressure gas refrigerant goes to the accumulator 244 via the four-way switching valve 241. The accumulator 244 holds the liquid refrigerant that remains slightly in the low-pressure gas refrigerant, and directs only the gas refrigerant to the compressor 100.

(4) Wear disappearance determination operation (4-1) Basic determination operation The current consumption of the motor 20 is acquired by the motor current detection unit 294 shown in FIG. The thickness detection unit 296 substitutes the acquired current value for a predetermined function representing the relationship between the current and the thickness, calculates the thickness value of the existing first lubricating layer 41, and outputs a thickness signal. When the thickness value indicated by the thickness signal deviates from the normal range stored in the normal range storage unit 298, the wear determination unit 299 determines that the first lubricating layer 41 has disappeared due to wear, and the compressor 100 operation is stopped.

(4-2) Correction Operation The current consumption of the motor 20 varies depending on the rotational speed of the shaft 30. Therefore, in the wear disappearance determination operation, in order to eliminate the influence of fluctuations in the rotational speed of the shaft 30, a correction operation may be performed in the following manner.

  First, reference data is accumulated over a long period of time from about 3 to 10 weeks after the installation of the refrigeration system 200. That is, in any operating state of the refrigeration system 200 performed during this period, the current consumption value acquired by the motor current detection unit 294, the rotation speed value acquired by the motor rotation speed detection unit 295, and the compressor 100 Is stored in the reference data storage unit 297 as reference data.

  Next, in actual use, when the current value is acquired by the motor current detection unit 294, the acquired current value is used for the reference data storage unit 297 in order to cancel the influence of the difference in rotational speed and the difference in pressure. Is corrected by calculation using the reference data stored in.

  The thickness detector 296 substitutes the corrected current value into a predetermined function representing the relationship between the current and the thickness, calculates the thickness value of the existing first lubricating layer 41, and outputs a thickness signal. Finally, the thickness signal based on the corrected current value is used for the wear loss determination of the first lubricating layer 41.

(5) Features (5-1)
The controller 290 compares the thickness signal related to the first lubricating layer 41 with a predetermined normal range to determine wear loss. Therefore, control for stopping the operation of the compressor 100 can be performed according to the determination result.

(5-2)
The degree of wear of the first lubricating layer 41 can be known by monitoring the current value. Therefore, wear loss determination is easy.

(5-3)
For the wear loss determination, a thickness signal based on the corrected current value is used. Therefore, the influence of the increase / decrease in the current value due to the fluctuation of the rotation speed of the shaft 30 can be eliminated, thereby improving the accuracy of the wear loss determination.

(6) Modification (6-1) Application of Modification of First Embodiment The modification described in the first embodiment may be applied to the compressor 100 of the refrigeration system 200 according to the present embodiment.

(6-2) Change in procedure of wear loss determination operation When the wear loss of the first lubricating layer 41 is determined, the thickness signal based on the corrected current value is calculated in the above-described procedure. However, the wear loss determination is not limited to this method. That is, the thickness signal may be first calculated by directly calculating the thickness from the uncorrected current value, and then the thickness signal may be corrected in order to eliminate the influence of fluctuations in the rotational speed. According to this procedure, depending on the design of the control unit 290, there is a possibility that the processing capability of the central processing unit 291 required for wear loss determination can be reduced.

  Alternatively, the target of the correction operation may be a value in the normal range stored in the normal range storage unit 298 instead of either the thickness value or the current value.

  Further, the wear disappearance determination may be any other procedure that can detect the disappearance of the first lubricating layer 41.

(6-3) Wear determination operation other than current monitoring When the wear disappearance is determined, the current value of the motor 20 is monitored in the above-described procedure. However, the wear loss determination is not limited to this method. That is, the wear loss determination may be performed using an optical sensor and a means such as image recognition without monitoring the current. According to this configuration, there is a possibility that the degree of wear of the first lubricating layer 41 can be determined more accurately.

A Rotating shaft M Metal powder P Porous material 10 Pressure vessel 20 Motor 30 Shaft 40 Slide bearing 41 First lubrication layer 42 Second lubrication layer 43 Base material 50 Fluid compression mechanism 100 Compressor 200 Refrigeration system 210 Connection piping 240 Heat source unit 241 Four-way selector valve 242 Heat source side heat exchanger 243 Heat source side pressure reducer 244 Accumulator 250 User unit 251 User side heat exchanger 252 User side pressure reducer 290 Controller 294 Motor current detector 295 Motor rotation speed detector 296 Thickness detector 297 Reference data storage unit 298 Normal range storage unit 299 Wear determination unit

JP 2011-1854 A

Claims (10)

A motor (20);
A shaft (30) rotated about a rotation axis (A) by the motor;
A fluid compression mechanism (50) driven by the shaft;
A plain bearing (40) for supporting the shaft;
With
The sliding bearing is
A first lubricating layer (41) having a first coefficient of friction and in contact with the shaft;
A second lubricating layer (42) having a second friction coefficient greater than the first friction coefficient and being further away from the rotating shaft than the first lubricating layer;
A base material (43) that is more distant from the rotating shaft than the second lubricating layer;
A compressor (100). The second friction coefficient is at least twice the first friction coefficient.
The compressor according to claim 1. The second friction coefficient is at least three times the first friction coefficient.
The compressor according to claim 2. The first lubricating layer and the second lubricating layer both have a porous material (P) and a resin impregnated in the porous material.
The compressor according to any one of claims 1 to 3. The porous material is a sintered body of metal powder (M).
The compressor according to claim 4. The first lubricating layer has a thickness of 50 μm or more and 100 μm or less;
The compressor according to any one of claims 1 to 5. The second lubricating layer has a thickness of 150 μm or more;
The compressor according to any one of claims 1 to 6. The compressor according to any one of claims 1 to 7,
Decompressors (243, 252),
A heat source side heat exchanger (242);
A use side heat exchanger (251);
A control unit (290) for controlling the compressor and the decompressor;
With
The controller is
A thickness detector (296) that outputs a thickness signal corresponding to the thickness of the first lubricating layer;
A normal range storage unit (298) for storing a normal range of the thickness signal;
A wear determination unit (299) for determining whether the thickness signal is within or outside the normal range;
Having
Refrigeration system (200). A current detector (294) for detecting a value of a current flowing through the motor;
Further comprising
The thickness signal is calculated based on the current value.
The refrigeration system according to claim 8. The controller is
A rotational speed detector (295) for detecting the rotational speed of the shaft;
A reference data storage unit (297) for storing the value of the current as reference data for various rotational speeds of the shaft during operation of the refrigeration system over a certain period of time;
Further comprising
The thickness signal is calculated based on the value of the current corrected using the rotation speed and the reference data.
The refrigeration system according to claim 9.

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