JP2006329157A - Oil injection type compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil injection type compressor which can intend to make cooling efficient without requiring local cooling defect of a driving motor by disappearing air cavity in a cooling jacket of the driving motor. <P>SOLUTION: In the oil injection type compressor provided with an oil circulating flow passage 12 which comes into fluid communication with the compressor itself 20 from an oil separation collector 10 and in which an oil cooler 13 which cools oil separated with the oil separation collector 10 is intervened, it is configured so as to intervene the cooling jacket 2b of the driving motor intermediate on downstream side of the oil circulating flow passage 12 in fluid communication with the compressor itself 20 from the oil cooler 13 and at the same time to bring a gas venting hole 4 provided on an upper portion of the cooling jacket 2b into fluid communication with a gas suction port 30a provided on downstream side from a suction regulator 7 of a suction flow passage 8 by the gas venting flow passage 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an oil-cooled compressor configured to supply oil to a compressor body for lubrication, shaft sealing, and cooling.

  Conventionally, a drive motor that drives an impeller and a screw rotor of a compressor rotates at a high speed and thus generates a large amount of heat, and a cooling mechanism that cools this is essential. As such a cooling mechanism, generally, forced cooling by a fan directly connected to a rotor shaft, supply of cooling air or a refrigerant by an external cooling device, and the like have been conventionally used.

  However, when the fan is directly connected to the rotor shaft, the rotor shaft length becomes long, so that it becomes difficult to support the rotation of the rotor shaft that rotates at high speed, and when cooling air or refrigerant is supplied by an external cooling device, A separate power source and a cooling machine are required, and the apparatus becomes complicated, resulting in a cost increase.

A conventional compressor and its cooling system that have been proposed to solve the above problems will be described below with reference to FIGS.
First, FIG. 3 is a sectional view showing a scroll-type air compressor for a fuel cell according to a conventional invention (see Patent Document 1).

  Reference numeral 100 in the figure denotes this scroll compressor. The compression mechanism section of the compressor 100 includes a fixed scroll 110 and a turning scroll 120 that orbits with respect to the fixed scroll 110. The compressor 100 compresses the fluid sucked with the turning of the turning scroll 120 and discharges 111. Discharge from.

  The orbiting scroll 120 is rotated by a drive motor 130 via a drive crankshaft 131 and revolves with respect to the fixed scroll 110 via a drive crank mechanism 150. The drive motor unit includes a drive motor 130 and a substantially bottomed cylindrical motor housing 190 that surrounds and houses the drive motor 130.

  An annular recess 191 serving as a cooling water channel is formed on the outer peripheral side of the motor housing 190, and a cylindrical outer cylinder 200 is provided around the motor housing 190. A cooling jacket 210 including a cooling water channel 211 hermetically sealed is formed by the annular recess 191 of the motor housing 190 and the outer cylinder 200 closed so as to cover it.

  The cooling water in the cooling jacket 210 flows from the inlet 202 protruding from the outer cylinder 200, passes between the fins 192 of the cooling water channel 211, and is guided to an outlet (not shown). Thus, the drive motor 130 is efficiently cooled by the cooling jacket 210.

  The outer cylinder 200 is integrally fixed to the center housing 170 by a plurality of bolts 220 or press-fitting. Since the center housing 170 and the motor housing 190 are fixed integrally, the outer cylinder 200 is fixed to the motor housing 190 integrally, though indirectly.

  Next, FIG. 4 is a sectional view showing a compressor (see Patent Document 2) in a screw refrigerator according to another conventional invention. The compressor 11 in the screw refrigerator is formed by a motor 21, a first stage compression unit 22, and a second stage compression unit 23, which share an integral casing 31. It is described that the casing 31 of the motor 21 has a liquid cooling structure that is cooled by water or a refrigerant liquid.

The compressor according to the above-described conventional invention described with reference to FIGS. 3 and 4 is cited to show a conventional example of the cooling structure of the oil-cooled compressor according to the present invention. Since the object of the compressor according to the invention is different from the present invention, further explanation is omitted.
JP 2003-35261 A JP 2002-266782 A

  According to the compressor according to the conventional example, in the compressor driven by the drive motor having the cooling jacket, water or refrigerant is used in the case of the compressor for the refrigerator, and oil is used as the coolant in the case of the gas compressor. It is common to use as Therefore, in the oil-cooled compressor according to the present invention, oil is also used as a coolant.

  FIG. 5 shows a cooling jacket for a drive motor of an oil-cooled compressor according to the prior art (hereinafter referred to as a cooling jacket) in a cross-sectional view as seen from the direction of arrows XX in FIG. . In FIG. 5, the cooling liquid is injected from a cooling liquid inlet 18 provided below the cooling jacket 2b, and circulates in the cooling path 2c to cool a drive motor main body (not shown) inside the motor housing 2a. Thereafter, the coolant is discharged from the coolant outlet 19 provided below the cooling jacket 2b.

  In the cooling jacket according to the conventional example, the cooling liquid is injected from the cooling liquid inlet 18 provided below the cooling jacket 2b, and similarly discharged from the cooling liquid outlet 19 provided below the cooling jacket 2b. As shown in FIG. 6, there is an example in which the cooling liquid is injected and discharged from the cooling liquid inlet 18 and the cooling liquid outlet 19 provided above the cooling jacket 2b as shown in FIG.

  In addition, as shown in FIG. 7, the cooling liquid is injected from the cooling water inlet 18 provided below the cooling jacket 2b and discharged from the cooling water outlet 19 provided above the cooling jacket 2b, or alternatively, FIG. In some cases, the coolant is injected from the coolant inlet 18 provided above the cooling jacket 2b and discharged from the coolant outlet 19 provided below the cooling jacket 2b.

  However, in any of the above conventional examples, an air pool is generated at a local location in the cooling jacket 2b, and as a result, local cooling failure and cooling efficiency decrease due to the difficulty of circulating the coolant. There was a problem.

  Accordingly, an object of the present invention is to provide an oil-cooled compressor capable of eliminating the local cooling failure of the drive motor and improving the efficiency of cooling by eliminating the air trap in the cooling jacket. is there.

  In order to achieve the above object, the means employed by the oil-cooled compressor according to claim 1 of the present invention includes a compressor body driven by a drive motor having a cooling jacket, and the suction of the compressor body. A suction flow path provided with a suction adjustment valve that adjusts the flow rate of the gas that flows into the suction port and is connected to the discharge port of the compressor body, and is included in the discharged compressed gas. An oil passage having an oil separation / recovery unit for collecting the oil component, and communicating with the compressor main body from the oil separation / recovery unit and cooling the oil separated by the oil separation / recovery unit In an oil-cooled compressor having an oil circulation channel in which a cooler is interposed, a downstream side of an oil circulation channel communicating from the oil cooler to the compressor body is defined as a first downstream oil channel and a second oil channel. Divided into a downstream oil flow path and divided into the first downstream oil flow path And a gas outlet hole provided in the upper portion of the cooling jacket, and a divided end portion of the second downstream oil passage is communicated with a cooling fluid outlet of the cooling jacket. The gas suction port provided on the downstream side of the suction adjustment valve of the suction channel is communicated with the gas vent channel.

  The means employed by the oil-cooled compressor according to claim 2 of the present invention is the oil-cooled compressor according to claim 1, wherein the gas suction port is provided in the compressor body, and is in the vicinity of the suction port. It is characterized by being.

  The means employed by the oil-cooled compressor according to claim 3 of the present invention is the oil-cooled compressor according to claim 1, wherein the gas suction port is provided in the suction flow path, and is in the vicinity of the suction port. It is characterized by being.

  The means employed by the oil-cooled compressor according to claim 4 of the present invention is the oil-cooled compressor according to any one of claims 1 to 3, wherein the throttle mechanism is provided in the gas vent passage. It is characterized by comprising.

  The means employed by the oil-cooled compressor according to claim 5 of the present invention is the oil-cooled compressor according to any one of claims 1 to 3, wherein an electromagnetic valve is provided in the gas vent passage. And a controller that controls opening and closing of the solenoid valve based on preset control conditions.

  The means employed by the oil-cooled compressor according to claim 6 of the present invention is that, in the oil-cooled compressor according to claim 5, the control condition preset in the controller is immediately after the drive motor is started. The electromagnetic valve is opened only for a predetermined time, and the electromagnetic valve is closed after the predetermined time has elapsed.

  The oil-cooled compressor according to claim 1 of the present invention divides the downstream side of the oil circulation passage communicating from the oil cooler to the compression main body into a first downstream oil passage and a second downstream oil passage. The split end portion of the first downstream oil passage is communicated with the cooling fluid inlet of the cooling jacket, and the split end portion of the second downstream oil passage is communicated with the cooling fluid outlet of the cooling jacket. The present invention relates to an oil cooling structure of an oil cooling compressor.

  The oil cooling structure of the oil cooling compressor communicates the gas vent hole provided in the upper part of the cooling jacket with the gas suction port provided on the downstream side of the suction adjustment valve of the suction flow path through the gas vent flow path. In addition, by adopting a configuration in which the accumulated gas in the cooling jacket is extracted to the compressor body side, air accumulation in the cooling jacket is eliminated, and local cooling failure and cooling efficiency decrease due to poor oil circulation. It is an improvement.

  Moreover, according to the oil-cooled compressor according to claim 2 of the present invention, in the oil-cooled compressor according to claim 1, the gas suction port is provided in the compressor body and in the vicinity of the suction port. Therefore, the negative pressure serves to reliably extract the staying gas in the cooling jacket.

  Furthermore, according to the oil-cooled compressor according to claim 3 of the present invention, in the oil-cooled compressor according to claim 1, the gas suction port is the suction flow path, and the suction of the compressor main body. Since it is provided in the vicinity of the mouth, as in the previous section, the negative pressure ensures the extraction of the staying gas in the cooling jacket.

  According to an oil-cooled compressor according to a fourth aspect of the present invention, in the oil-cooled compressor according to any one of the first to third aspects, a throttle mechanism is provided in the gas vent passage. Therefore, it is possible to suppress a decrease in oil in the cooling jacket and suppress a decrease in cooling efficiency.

  On the other hand, according to the oil-cooled compressor according to claim 5 of the present invention, in the oil-cooled compressor according to any one of claims 1 to 3, the gas vent flow path is electromagnetically coupled. Since the controller is provided to control opening and closing of the electromagnetic valve based on a preset control condition while interposing a valve, by opening and closing the electromagnetic valve as necessary after starting the compressor, Cooling efficiency can be improved without causing a reduction in oil in the cooling jacket.

  Furthermore, according to the oil-cooled compressor according to claim 6 of the present invention, in the oil-cooled compressor according to claim 5, the control condition preset in the controller is that the drive motor is started. By opening the solenoid valve for a predetermined time immediately after that and closing the solenoid valve after a predetermined time has elapsed, it is possible to reliably suppress the decrease in oil in the cooling jacket and improve the efficiency of cooling. Can be planned.

  First, an oil-cooled compressor according to Embodiment 1 of the present invention will be described below with reference to FIG.

  The compressor includes a compressor body 20 having a structure in which a pair of male and female screw rotors 22 (not shown) are meshed with each other and rotatably accommodated in the compressor body casing 21. A suction flow path 8 is connected to the suction port 20a of the compressor body 20, and one end side of the discharge flow path 9 is connected to the discharge port 20b.

  Only one of the male and female screw rotors 22 constituting the compressor main body 20 is connected to the drive shaft 11 of the drive motor 1 as shown. By rotating the screw rotor 22 by the drive motor 1, the gas supplied from the suction passage 8 is compressed by the compressor body 20 and discharged to the discharge passage 9 as a high-pressure fluid.

  The drive motor 1 is housed in a motor housing (corresponding to reference numeral 2 a in FIGS. 5 to 8) inside the motor casing 2, and the motor casing 2 is integrally coupled to the compressor body casing 21. The drive motor 1 includes a stator 26 fixed to the inner surface of the motor casing 2 and a rotor 27 that rotates about the drive shaft 11, and the rotation of the drive motor 1 is controlled by a controller 25. And this drive motor 1 is transmitting the rotational force of the said drive shaft 11 to the screw rotor 22 of the compressor main body 20 via the bearing 23a.

  The motor casing 2 includes a motor housing 2a that is an outer shell of the drive motor, and a cooling jacket 2b that is provided outside the motor housing 2a and forms a cooling path 2c through which oil (coolant), which will be described later, communicates. Become. In that respect, the configuration is the same as that of FIGS.

  The suction flow path 8 is provided with a suction adjustment valve 7 for adjusting the flow rate of gas passing through the suction flow path 8, and the valve opening degree is controlled by the controller 25. An oil separation / recovery device 10 is interposed in the discharge flow path 8, and an oil separation element 10 a is provided in the oil separation / recovery device 10.

  Since the oil is slightly mixed in the high-pressure gas flowing into the oil separation / recovery device 10, the oil is captured by the oil separation element 10 a provided inside the oil separation / recovery device 10. The oil trapped by the oil separation element 10a is dropped by its own weight, and an oil reservoir 10b is formed below the oil separation / recovery device 10 inside.

  The oil recovered in the oil reservoir 10b in this manner is circulated by an oil pump (not shown) through the oil circulation passage 12 communicating from the oil separator / collector 10 to the compressor body 20. An oil cooler 13 is interposed in the oil circulation passage 12, and the oil passing therethrough is cooled by temperature control by the controller 25.

  Of the oil circulation channels 12, the downstream oil circulation channels 12 communicating from the oil cooler 13 to the compressor body 20 are divided into a first downstream oil channel 16 and a second downstream oil channel 17. And the split end of the first downstream oil passage 16 is communicated with the cooling fluid inlet 18 of the cooling jacket 2b. At the same time, the divided end portion of the second downstream oil passage 17 is communicated with the cooling fluid outlet 19 of the cooling jacket 2b.

  On the other hand, the oil cooled by the oil cooler 13 is injected into the cooling passage 2 c from the cooling fluid inlet 18 provided in the cooling jacket 2 b of the motor casing 2 through the first downstream oil passage 16. In addition, a three-way valve 14 is interposed in the oil circulation flow path 12 on the upstream side from the oil separator / collector 10 to the oil cooler 13, and the oil cooler 13 extends from the three-way valve 14. The remaining oil that has not reached the flow passes through the bypass flow path 15 from the three-way valve 14 and then merges with the oil cooled by the oil cooler 13.

  Here, the three-way valve 14 is configured to cool the drive motor 1 to an appropriate temperature and supply an oil amount to an oil cooler 13 interposed in the oil circulation passage 12 so as to reach a preset target temperature; The controller 25 commands a distribution ratio with the amount of oil that flows through the bypass flow path 15 as it is without being supplied to the oil cooler 13, and the valve opening and closing is controlled according to the command signal.

  Then, similarly to the conventional example described with reference to FIGS. 5 to 8, the cooled oil is injected into the cooling passage 2c through the cooling fluid inlet 18 provided in the cooling jacket 2b of the motor casing 2, and the motor The internal drive motor 1 is cooled through the housing 2a. The oil that has finished cooling the drive motor 1 is supplied to the compressor body casing 21 from the cooling fluid outlet 19 of the motor casing 2 through the second downstream oil passage 17 in which the oil filter 24 is interposed. Is supplied to the oil supply port 28 that needs to be supplied.

  Such an oil supply port 28 is formed by the oil supply port 28a to the suction side bearing / shaft seal 23a, the oil supply port 28b to the discharge side bearing / shaft seal 23b, the screw rotor 22 and the compressor body casing 21. It is comprised from the oil supply port 28c to the compression space which carries out.

  Further, a gas vent hole 4 is provided in the upper portion of the cooling jacket 2b of the motor casing 2 in addition to the cooling fluid inlet 18 and the cooling fluid outlet 19, and the suction regulating valve of the gas vent hole 4 and the suction flow path 8 is provided. 7 is connected to the gas suction port provided on the downstream side by the gas vent passage 3 so as to extract the staying gas in the cooling jacket 2b to the compressor body 20 side.

  And it is preferable to provide the said gas inlet in the compressor main body casing 21 in the vicinity of the inlet 20a of the compressor main body 20, as shown by the code | symbol 30a of FIG. By adopting such a configuration, during the operation of the compressor, the vicinity of the suction port 20a of the compressor body 20 has a negative pressure equal to or lower than the atmospheric pressure, so that the stagnant gas in the cooling jacket 2b is easily generated. Thus, the cooling efficiency of the cooling jacket 2b can be improved and local cooling failure can be eliminated.

  In the suction flow path 8, the pressure loss due to the suction adjustment valve 7 and the suction flow path 8 is between the upstream side of the suction adjustment valve 7 shown in FIG. 1 and the vicinity of the suction port 20 a of the compressor body 20. As a result, a pressure difference occurs during compressor operation. For example, in a compressor with a rated output of 15 kW, the pressure at the suction port 20a is about 2.27 kPa lower than the upstream pressure (= atmospheric pressure) of the suction adjustment valve 7 during operation.

  Since the pressure in the cooling jacket 2b is slightly higher than the atmospheric pressure due to the vapor pressure of the oil, this pressure, combined with the negative pressure, exhausts the staying gas in the cooling jacket 2b, and the compressor body 20 The action is taken out reliably to the side.

  Further, in order to surely cool the inside of the motor casing 2, it is desirable that oil is not circulated from the cooling fluid outlet 19 to the compressor body 20 side more than necessary. On the other hand, oil other than the gas retained in the cooling jacket 2b from the gas vent hole 4 through the gas vent channel 3 may be supplied to the compressor body 20 side along with the gas flow. . If the amount of oil supplied to the compressor main body 20 through the gas vent flow path 3 becomes large, there is a possibility that proper cooling of the drive motor 1 cannot be maintained.

  For this reason, although not shown in the drawing, in order to prevent such a large amount of oil from being supplied by the gas vent channel 3, it is preferable to provide a throttle mechanism in the gas vent channel 3. The term “throttle mechanism” as used herein refers to a mechanism having a function of narrowing the flow rate of fluid passing through the gas vent channel 3 such as an orifice, a venturi, or a flow rate adjusting valve.

  Alternatively, in order to prevent a large amount of oil from being supplied through the gas vent channel 3, an electromagnetic valve 5 is provided in the gas vent channel 3 as shown in FIG. A controller 25 for controlling the electromagnetic valve 5 is preferably provided. The preset control condition is more preferably a condition in which the electromagnetic valve 5 is opened for a predetermined time immediately after the drive motor 1 is started and the electromagnetic valve 5 is closed after the predetermined time has elapsed. . With the above-described configuration, a large amount of oil can be automatically prevented from being supplied through the gas vent channel 3.

  Next, the oil cooling structure of the oil cooling type compressor according to the second embodiment of the present invention will be described below with reference to FIG. 2 which is a cooling system diagram thereof. Note that the second embodiment of the present invention differs from the first embodiment in that the position of the gas suction port provided on the downstream side of the suction adjustment valve 7 of the suction flow path 8 is different, and the rest is completely the same configuration. The description of the configuration of the gas vent channel 3 will be stopped.

  That is, in Embodiment 1 of the present invention, the attachment position of the gas vent channel 3 to the compressor body 20 side is as shown in FIG. 1 in the compressor body casing 21 in the vicinity of the suction port 20a of the compressor body 20. Although it was set as the structure provided in the provided gas suction port 30a, it was set as the structure provided in the gas suction port 30b of the suction flow path 8 vicinity of the suction port 20a as shown in FIG. By adopting such a configuration, it is possible to efficiently extract the staying gas in the cooling jacket 2b and obtain the same effect as in the first embodiment.

  As described above, in the oil-cooled compressor according to the present invention, the downstream oil passage of the oil circulation passage communicating from the oil cooler to the compression body is divided into the first downstream oil passage and the second downstream oil flow. And the divided end of the first downstream oil passage is communicated with the cooling fluid inlet of the cooling jacket, and the divided end of the second downstream oil passage is connected to the cooling fluid outlet of the cooling jacket. The present invention relates to an oil cooling structure of an oil cooling type compressor communicated with the oil cooling type.

  The oil cooling structure of the oil cooling compressor communicates the gas vent hole provided in the upper part of the cooling jacket with the gas suction port provided on the downstream side of the suction adjustment valve of the suction flow path through the gas vent flow path. In addition, by adopting a configuration in which the accumulated gas in the cooling jacket is extracted to the compressor body side, air accumulation in the cooling jacket is eliminated, and local cooling failure and cooling efficiency decrease due to poor oil circulation. It is an improvement.

  Further, since the gas suction port provided on the downstream side of the suction adjustment valve of the suction channel is configured to be provided in the vicinity of the suction port in the compressor body or in the vicinity of the suction port in the suction channel, the retained gas in the cooling jacket The negative pressure necessary for extracting the compressor to the compressor body side is more reliably secured.

  The oil-cooled compressor according to the present invention has been described by taking the screw compressor as an example as described above, but it goes without saying that the gist can be applied to other turbo compressors, reciprocating compressors, and the like. Moreover, although the form which concerns on this invention demonstrated by the figure which the drive coaxial of the electric motor was directly connected with the rotor shaft of the compressor main body, it is natural also when transmitting rotation via a coupling or a reduction gear between both shafts. included.

  In the first and second embodiments of the present invention, the drive motor 1, the solenoid valve 5, the suction regulating valve 7, the oil cooler 13, and the three-way valve 14 are controlled by the controller 25 that is the same control device. However, the present invention is not limited to this. These may be controlled by different control devices.

It is a cooling system figure of the oil cooling type compressor concerning form 1 of the present invention. It is a cooling system figure of the oil cooling type compressor concerning form 2 of the present invention. It is sectional drawing of the conventional scroll type air compressor. It is sectional drawing of the compressor in the conventional screw refrigerator. It is sectional drawing which shows arrow XX of FIG. It is sectional drawing applicable to FIG. 5 which concerns on another prior art example. It is sectional drawing applicable to FIG. 5 which concerns on another another prior art example. It is sectional drawing applicable to FIG. 5 which concerns on another another prior art example.

Explanation of symbols

1 ... Drive motor,
2 ... Motor casing, 2a ... Motor housing, 2b ... Cooling jacket, 2c ... Cooling path,
3 ... Gas vent flow path, 4 ... Gas vent hole, 5 ... Solenoid valve, 7 ... Suction adjustment valve, 8 ... Suction flow path,
9: Discharge flow path,
10 ... Oil separator / collector, 10a ... Oil separator element, 10b ... Oil reservoir,
DESCRIPTION OF SYMBOLS 11 ... Drive shaft, 12 ... Oil circulation flow path, 13 ... Oil cooler, 14 ... Three-way valve,
15 ... Bypass channel, 16 ... First downstream oil channel, 17 ... Second downstream oil channel,
18 ... Cooling fluid inlet, 19 ... Cooling fluid outlet,
20 ... Compressor body, 20a ... Suction port, 20b ... Discharge port,
21 ... Compressor body casing,
22 ... Screw rotor, 22a ... Male screw rotor,
23a ... Suction side bearing / shaft seal, 23b ... Discharge side bearing / shaft seal,
24 ... Oil filter, 25 ... Controller, 26 ... Stator, 27 ... Rotor,
28, 28a, 28b, 28c ... oil supply port,
30a, 30b ... Gas inlet

Claims (6)

  A suction flow path including a compressor body driven by a drive motor having a cooling jacket, and provided with a suction adjustment valve that communicates with the suction port of the compressor body and adjusts the flow rate of the gas flowing into the suction port. And having a discharge passage in which one end side is connected to a discharge port of the compressor main body, and an oil separation and recovery unit for recovering oil contained in the discharged compressed gas is provided, and the oil separation and recovery unit An oil-cooled compressor having an oil circulation passage that is connected to the compressor main body and in which an oil cooler that cools the oil separated by the oil separation and recovery unit is interposed, from the oil cooler to the compressor A downstream side of the oil circulation passage communicating with the main body is divided into a first downstream oil passage and a second downstream oil passage, and a divided end portion of the first downstream oil passage is formed on the cooling jacket. And communicating with the cooling fluid inlet and the second downstream oil flow The split end portion of the cooling jacket is communicated with a cooling fluid outlet of the cooling jacket, and a gas vent hole provided in the upper portion of the cooling jacket and a gas suction port provided on the downstream side of the suction adjustment valve of the suction passage An oil-cooled compressor characterized by being connected by a road.   The oil-cooled compressor according to claim 1, wherein the gas suction port is provided in the compressor body and is in the vicinity of the suction port.   The oil-cooled compressor according to claim 1, wherein the gas suction port is provided in the suction flow path and is in the vicinity of the suction port.   The oil-cooled compressor according to any one of claims 1 to 3, wherein the gas vent passage is provided with a throttle mechanism.   4. The controller according to claim 1, further comprising: a controller that interposes an electromagnetic valve in the gas vent passage and controls opening and closing of the electromagnetic valve based on a preset control condition. 5. The oil-cooled compressor as described in one term.   The control condition set in advance in the controller is to open the solenoid valve for a predetermined time immediately after starting the drive motor, and to close the solenoid valve after a predetermined time has elapsed. The oil-cooled compressor according to claim 5.

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