Compressor operation control method and compressor

Abstract

The invention provides a compressor operation control method and a compressor. The present invention ensures stable oil supply to a compressor main body during cooling operation, and prevents the compressor main body from reversing when a drive source is stopped. The cooling operation is divided into a stop preparation period, which is a predetermined period immediately before a drive source such as an engine is stopped, and a main operation period, which is a period from the start of the cooling operation to the stop preparation period. The pressure in the receiving container (60) during the main operation period is set to be equal to or greater than a stable pressure P3 at which oil can be stably supplied to the compressor body (40), and the pressure in the receiving container (60) during the stop preparation period is reduced to a lower limit stable pressure P4, which is a pressure at which the compressor body (40) is not reversed when the drive source is stopped, and thereafter the drive source is stopped.

Description

Technical Field

[0001] The present invention relates to an operation control method for a compressor and a compressor that executes the operation control method. More specifically, it relates to an operation control method for a compressor that performs a predetermined cooling operation before stopping a driving source such as an engine that drives the compressor body, and has characteristics in its actions during the cooling operation, and a compressor that executes the operation control method. Background Art

[0002] Figure 8 The present invention shows a configuration example of an engine-driven compressor 300 including an oil-cooled screw compressor as a compressor main body 340 . The oil-cooled screw compressor compresses a compressed gas together with lubricating oil and discharges the compressed gas as a gas-liquid mixed fluid.

[0003] The engine-driven compressor 300 includes the aforementioned compressor body 340, an engine (not shown), and a receiving tank 360. The receiving tank 360 receives the compressed gas discharged from the compressor body 340 as a gas-liquid mixed fluid containing lubricating oil and separates the lubricating oil from the compressed gas. Furthermore, the compressed gas, from which the lubricating oil has been separated in the receiving tank 360, is configured to be supplied to an air-working machine (not shown), etc., connected to a service valve 366. Furthermore, the lubricating oil recovered in the receiving tank 360 is configured to be supplied to the compressor body 340 via an oil supply passage 364 equipped with an oil cooler 363 and an oil filter 365, utilizing the pressure within the receiving tank 360.

[0004] Such an engine driven compressor 300 is provided with an intake air regulating device 310 for regulating the intake air volume of the compressor body 340 according to the pressure in the receiving container 360 so as to stably supply compressed gas to the consumption side.

[0005] exist Figure 8 In the engine-driven compressor 300 shown, the intake adjustment device 310 is composed of an intake adjustment valve 311 for opening and closing the intake port of the compressor body 340, a control flow channel 312 connecting the closed valve pressure receiving chamber 311a of the intake adjustment valve 311 and the receiving container 360, and a pressure regulator 313 for controlling the opening and closing of the control flow channel 312.

[0006] By setting up such an intake adjustment device 310, when the pressure in the receiving container 360 drops to a level lower than the working starting pressure of the pressure regulator 313 due to the consumption of compressed gas on the consumption side, the pressure regulator 313 closes the control flow channel 312, so that the working pressure is not introduced into the closed valve pressure receiving chamber 311a of the intake adjustment valve 311, but by opening the intake adjustment valve 311, the compressor body 340 sucks in the compressed gas and compresses it to generate compressed gas.

[0007] On the other hand, if the consumption of compressed gas on the consumption side stops and the pressure in the receiving container 360 rises, the pressure regulator 313 opens, and compressed gas begins to be introduced into the closed valve pressure receiving chamber 311a of the intake adjustment valve 311. Since the intake adjustment valve 311 throttles or closes the intake port of the compressor body 340 according to the pressure increase in the receiving container 360, the compressor body 340 reduces the amount of compressed gas generated or stops the generation of compressed gas.

[0008] In the engine-driven compressor 300 constructed as described above, the following situation occurs: even if the power switch is turned off and a stop command for the engine-driven compressor 300 is input, the engine does not stop immediately. Instead, the engine and the compressor body 340 continue to operate under a low load in a so-called "cooling operation" until the temperature of the engine and the compressor body 340 (for example, the temperature of the coolant or lubricating oil) drops to a predetermined temperature or a predetermined cooling time has passed, and then the engine is stopped.

[0009] As an engine-driven compressor that performs such a cooling operation, Patent Document 1 described below describes an engine-driven compressor 300, which includes a bypass flow path (323, 324) that bypasses a pressure regulator 313 and connects a receiving container 360 to a closed valve pressure-receiving chamber 311a of an intake regulating valve 311, an electromagnetic on-off valve (331, 332) that opens and closes the bypass flow path, and a release flow path 314 that exhausts compressed gas in the closed valve pressure-receiving chamber 311a of the intake regulating valve 311 via a throttle portion 315.

[0010] In the engine-driven compressor 300 described in Patent Document 1, during cooling operation, the electromagnetic on-off valves 331 and 332 are opened to introduce the compressed gas in the receiving container 360 into the closed valve pressure receiving chamber 311a of the intake regulating valve 311 via the bypass flow passages 323 and 324, and the compressed gas in the closed valve pressure receiving chamber 311a is exhausted via the release flow passage 314, thereby performing cooling operation while the pressure in the receiving container 360 is reduced. Even if the pressure regulator 313 closes the control flow passage 312 due to the pressure reduction in the receiving container 360, compressed gas can be introduced into the closed valve pressure receiving chamber 311a via the bypass flow passages 323 and 324, thereby maintaining the closed valve state of the intake regulating valve 311 (paragraphs

[0112] to

[0117] of Patent Document 1).

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 2021-179186

[0012] In reference Figure 8In the engine-driven compressor 300 described in the patent document 1, during cooling operation, the intake port of the compressor body 340 is blocked by the intake regulating valve 311, and the pressure in the receiving container 360 is reduced to reduce the back pressure of the compressor body 340, thereby reducing the load applied to the compressor body 340 during cooling operation, and further reducing the load applied to the engine. As a result, not only can the engine and the compressor body 340 be cooled efficiently, but cooling operation can also be performed with a low fuel consumption rate.

[0013] Furthermore, in an attempt to further reduce the load applied to the engine during cooling operation, it may be considered to reduce the pressure in the receiving container 360 to a pressure close to atmospheric pressure to reduce the back pressure of the compressor body 340 as much as possible.

[0014] However, in order to efficiently cool the compressor body 340 during cooling operation and prevent seizure of the compressor body 340, it is necessary to stably supply lubricating oil cooled by the oil cooler 363 to the compressor body 340. As described above, lubricating oil is supplied to the compressor body 340 using the pressure within the receiving container 360. Therefore, if the pressure within the receiving container 360 is significantly reduced to a pressure close to atmospheric pressure during cooling operation, oil will no longer be supplied to the compressor body 340.

[0015] Therefore, even if the pressure in the receiving container 360 during cooling operation becomes lower than that during normal operation, it is necessary to set it to a relatively high pressure so that lubricating oil can be stably supplied to the compressor body 340 when oil is supplied through the oil supply channel 364 equipped with equipment that causes pressure loss, such as the oil filter 365 and the oil cooler 363.

[0016] On the other hand, when the engine is stopped to terminate the cooling operation, the compressor body 340 stops rotating as the engine stops, and the compressed gas in the receiving container 360 begins to flow into the compressor body 340. At this time, the pressure in the receiving container 360 is high. If the torque of the compressed gas flowing into the compressor body 340, which attempts to rotate the screw rotor in the reverse direction, exceeds the rotational resistance applied to the screw rotor by the stopped engine, the screw rotor of the compressor body 340 rotates in the reverse direction, and the engine coupled to the rotor shaft of the compressor body 340 also rotates in the reverse direction.

[0017] Such reverse rotation of the compressor body 340 and the engine may cause adverse effects on the components of the engine-driven compressor 300, such as shortening the life of the oil seal provided in the compressor body 340 or shortening the life of the fan belt of the engine by causing the fan belt to slide.

[0018] To prevent such a reverse rotation of the compressor main body 340 and the engine, it is also possible to consider providing a check valve between the compressor main body 340 and the receiving container 360 to prevent the compressed gas from flowing to the side of the compressor main body 340, or providing a locking mechanism that prevents the reverse rotation of the engine and the compressor main body 340, but the addition of such a check valve and the locking mechanism increases the manufacturing cost of the engine-driven compressor 300.

[0019] In addition, in the above description, the engine-driven compressor provided with an engine as a driving source is exemplified, but the same problem occurs when the cooling operation is performed in a compressor provided with a driving source other than an engine, such as a motor. SUMMARY

[0020] Therefore, the present application is an invention made to solve the above-described problems in the prior art, and the first object is to provide a method for controlling the operation of a compressor and a compressor that executes the method for controlling the operation of a compressor, in which, in a compressor in which the above-described cooling operation is performed, the reverse rotation of the compressor main body and the driving source is prevented when the cooling operation is ended by stopping the driving source such as an engine.

[0021] In addition, the second object of the present application is to provide a method for controlling the operation of a compressor and a compressor that executes the method for controlling the operation of a compressor, in which, in addition to preventing the reverse rotation of the compressor main body and the driving source when the cooling operation is ended by stopping the driving source, stable oil supply to the compressor main body can also be ensured when the cooling operation is performed by reducing the pressure in the receiving container.

[0022] Hereinafter, the means for solving the problems will be described together with the reference numerals used in the mode for carrying out the invention. The reference numerals are used to clearly show the correspondence between the description in the claims and the description in the mode for carrying out the invention, and are obviously not used to limit the interpretation of the technical scope of the present application.

[0023] In order to achieve the above-mentioned object, in the operation control method of the compressor 1 of the present invention, the compressor 1 includes: an oil-cooled compressor body 40; a driving source (not shown) such as an engine and a motor, which drives the compressor body 40; a receiving container 60 for introducing the compressed gas ejected from the compressor body 40; an oil supply flow path 64, which connects the receiving container 60 with the compressor body 40 and uses the pressure in the receiving container 60 to supply oil to the compressor body 40; a discharge flow path 20, which discharges the compressed gas in the receiving container 60; and an intake regulating valve 11, which opens and closes the intake port of the compressor body 40. The compressor 1 performs unloading operation and cooling operation. The unloading operation is to operate in a state where the pressure in the receiving container 60 is maintained at a predetermined unloading operation pressure P1 when the intake regulating valve 11 is closed. The cooling operation is to operate in a state where the pressure in the receiving container 60 is reduced by discharging the compressed gas through the discharge flow path 20 when the intake regulating valve 11 is closed before stopping the driving source. When the intake regulating valve 11 is closed, a small amount of compressed gas can be introduced into the compressor body 40. The cooling operation period is divided into a stop preparation period, which is a period immediately before the drive source is stopped, and a main operation period, which is a period from the start of the cooling operation to the stop preparation period. By changing the flow area of ​​the discharge flow passage 20, the pressure in the receiving container 60 is reduced to a stable pressure P3 (for example, 0.3 MPa) during the main operation period. The stable pressure P3 is a pressure that is a predetermined amount lower than the unloading operation pressure P1 and is a pressure that enables stable oil supply to the compressor body 40. During the stop preparation period, the pressure in the receiving container 60 is reduced to a lower limit stable pressure P4 (for example, 0.1 MPa). The lower limit stable pressure P4 is a pressure that is lower than the stable pressure P3 and higher than the atmospheric pressure P0 and is a pressure that prevents the compressor body 40 from rotating in reverse when the drive source is stopped. Thereafter, the drive source is stopped, and the cooling operation is terminated.

[0024] In the main operation period, after the pressure in the receiving container 60 is reduced to the stable pressure P3, it is preferred that the pressure be maintained at the stable pressure P3 until the end of the main operation period.

[0025] In the above-mentioned operation control method, a reference pressure P2 (for example, 0.5 MPa) may also be set. The reference pressure is a pressure that is lower than the unloading operation pressure P1 and higher than the stable pressure P3 (for example, 0.3 MPa) by a predetermined amount. The flow channel area of ​​the discharge flow channel 20 in the main operation period is changed in such a manner that the pressure reduction rate when the pressure in the receiving container 60 decreases from the unloading operation pressure P1 to the reference pressure P2 is higher than the pressure reduction rate when the pressure decreases from the reference pressure P2 to the stable pressure P3.

[0026] Furthermore, after the cooling operation is completed, it is preferred that the compressed gas continue to be discharged from the discharge passage 20 to reduce the pressure in the receiving container 60 to atmospheric pressure.

[0027] In addition, the compressor 1 of the present invention includes: an oil-cooled compressor body 40; a driving source (not shown) such as an engine or a motor, which drives the compressor body 40; a receiving container 60 for introducing the compressed gas ejected from the compressor body 40; an oil supply flow channel 64, which connects the receiving container 60 with the compressor body 40 and uses the pressure in the receiving container 60 to supply oil to the compressor body 40; a discharge flow channel 20, which discharges the compressed gas in the receiving container 60; and an intake regulating valve 11, which opens and closes the intake port of the compressor body 40. The compressor 1 performs unloading operation and cooling operation. The unloading operation The compressor 1 is operated in a manner that the pressure in the receiving container 60 is maintained at a predetermined unloading operation pressure P1 when the intake regulating valve 11 is closed. The cooling operation is operated in a manner that the pressure in the receiving container 60 is reduced by discharging compressed gas through the discharge flow passage 20 before stopping the driving source. The compressor 1 is provided with: a small intake flow passage (not shown) for introducing a small amount of compressed gas into the compressor body 40 when the intake regulating valve 11 is closed; and a variable throttling mechanism 30 for varying the flow area of ​​the discharge flow passage 20. and a control device 70 for controlling the operation of the variable throttle mechanism 30 and the drive source, and pre-dividing the cooling operation period into a stop preparation period as a period immediately before the drive source is stopped, and a main operation period as a period from the start of the cooling operation to the stop preparation period, wherein the control device 70 stores the end conditions of the main operation period and the stop preparation period, and controls the operation of the variable throttle mechanism 30 and the drive source, wherein the control device 70 sets the discharge flow path 20 in a manner that reduces the pressure in the receiving container 60 to a stable pressure P3 during the main operation period. The flow channel area of ​​the discharge flow channel 20 is set, the stable pressure P3 is a pressure that is a predetermined amount lower than the unloading operation pressure P1, and is a pressure that can stably supply oil to the compressor main body 40. The control device 70 sets the flow channel area of ​​the discharge flow channel 20 in the stop preparation period so that the pressure in the receiving container 60 is reduced to the lower limit stable pressure P4. The lower limit stable pressure P4 is a pressure that is lower than the stable pressure P3 and higher than the atmospheric pressure P0, and is a pressure that does not cause the compressor main body 40 to reverse when the driving source stops. The control device 70 stops the driving source thereafter to end the cooling operation.

[0028] Preferably, the control device 70 is configured to control the variable throttle mechanism 30 during the main operation period so that the flow area of ​​the discharge flow path 20 becomes the flow area maintained at the stable pressure P3 after the pressure in the receiving container 60 is reduced to the stable pressure P3.

[0029] It can also be configured that, in any of the above-mentioned compressors 1, a pressure detecting component (pressure sensor) 25 is provided for detecting that the pressure in the receiving container 60 becomes a reference pressure P2, and the reference pressure P2 is a pressure lower than the unloading operation pressure P1 and higher than the stable pressure P3 by a predetermined amount, and the control device 70 controls the variable throttling mechanism 30 during the main operation period in such a manner that the flow path area after the reference pressure P2 is detected changes relative to the flow path area from the start of the cooling operation to the time when the pressure detecting component 25 detects the reference pressure P2, so that the pressure reduction rate when the pressure in the receiving container 60 decreases from the unloading operation pressure P1 to the reference pressure P2 is higher than the pressure reduction rate when the pressure decreases from the reference pressure P2 to the stable pressure P3.

[0030] It is preferable that the variable throttle mechanism 30 is configured to maintain the discharge flow path 20 in an open state even after the cooling operation is completed.

[0031] The variable throttle mechanism 30 may be composed of a plurality of electromagnetic on-off valves 31 and 32 having different bore diameters and arranged in parallel in the discharge flow passage 20 ( Figure 1 ).

[0032] When the variable throttle mechanism 30 is composed of a plurality of electromagnetic on-off valves 31 and 32 having different bore diameters and arranged in parallel in the discharge flow path 20, it is preferable that at least one of the electromagnetic on-off valves 31 and 32 is a normally open (NO) electromagnetic on-off valve ( Figure 1 ).

[0033] In addition, the variable throttle mechanism 30 may include electro-pneumatic proportional valves 33, 35 ( Figure 3 、 Figure 6 ).

[0034] The variable throttle mechanism 30 may also be configured to include a normally closed (NC) electro-pneumatic proportional valve 33 and a normally open (NO) electromagnetic on-off valve 34 ( Figure 3 ).

[0035] Alternatively, the variable throttle mechanism 30 may be configured as a normally open (NO type) electro-pneumatic proportional valve 35 provided in the discharge flow path 20 ( Figure 6 ).

[0036] According to the configuration of the present invention described above, the following remarkable effects can be obtained in the compressor 1 of the present invention.

[0037] By reducing the pressure in the receiving container 60 to the lower limit stable pressure P4 during the stop preparation period, which is the period immediately before the drive source is stopped during the cooling operation, and then stopping the drive source to end the cooling operation, it is possible to prevent the compressor body 40 and the drive source from being reversed due to the stop of the drive source and then the stopping of the compressor body 40.

[0038] As a result, it is possible to prevent deterioration of the oil seal and the fan belt caused by reverse rotation of the compressor body or the drive source (eg, engine) when the drive source is stopped.

[0039] Furthermore, in addition to the above-described structure, in a structure in which the pressure in the receiving container 60 is reduced to the stable pressure P3 during the main operation period and then maintained at the stable pressure P3 until the end of the main operation period, not only can the compressor body 40 and the drive source be prevented from reversing when the drive source is stopped, but also during the cooling operation performed by reducing the pressure in the receiving container 60, sintering of the compressor body, etc., which may be caused by poor oil supply, can be reliably prevented.

[0040] A pressure, namely a reference pressure P2, which is lower than the unloading operation pressure P1 and higher than the stable pressure P3 by a predetermined amount, is set, and the flow channel area of ​​the discharge flow channel 20 during the main operation period is changed in such a manner that the pressure reduction rate when the pressure in the receiving container 60 decreases from the unloading operation pressure P1 to the reference pressure P2 is higher than the pressure reduction rate when the pressure in the receiving container 60 decreases from the reference pressure P2 to the stable pressure P3. In this case, the pressure in the receiving container 60 can be reduced at the beginning of the cooling operation, the load applied to the drive source can be reduced as early as possible, the drive source (such as the engine) and the compressor body can be cooled efficiently, and the fuel consumption rate during the cooling operation can be reduced.

[0041] In the structure in which the discharge flow passage 20 continues to discharge the compressed gas in the receiving container 60 after the driving source stops, the pressure in the receiving container 60 can be reduced to the atmospheric pressure P0, and the next startup of the compressor can be smoothly performed.

[0042] By forming a variable throttling mechanism 30 provided in the discharge flow channel 20 by a plurality of electromagnetic opening and closing valves 31 and 32 with different drilling diameters arranged in parallel in the discharge flow channel 20, the flow channel area of ​​the discharge flow channel 20 can be easily changed by changing the opening and closing modes of the plurality of electromagnetic opening and closing valves 31 and 32.

[0043] Furthermore, under this structure, it is possible to maintain a reference to Figure 8The main structure of the existing engine-driven compressor 300 described above remains unchanged, and the electromagnetic on-off valve used is replaced with an electromagnetic on-off valve having a predetermined drilling diameter, and the program of the control device that controls the operation of the electromagnetic on-off valve is rewritten, so that a compressor that executes the operation control method of the present invention can be provided relatively simply and at low cost.

[0044] When the variable throttle mechanism 30 is constituted by a plurality of electromagnetic on-off valves 31 and 32 having different bore diameters arranged in parallel in the discharge flow path 20 as described above, at least one of the electromagnetic on-off valves 31 and 32 (in Figure 1 In the embodiment, the second electromagnetic on-off valve (32) is a normally open (NO) electromagnetic on-off valve. Therefore, if the drive source stops and the power to the electromagnetic on-off valves (31 and 32) stops, the normally open (NO) electromagnetic on-off valve opens, allowing the compressed gas in the receiving container (60) to continue to be discharged through the discharge flow path (20) even after the drive source stops. This reduces the pressure in the receiving container (60) to atmospheric pressure (P0), allowing for smooth startup of the compressor (1) the next time.

[0045] The variable throttle mechanism 30 may include electro-pneumatic proportional valves 33 and 35 as components, thereby making it possible to change the flow channel area of ​​the discharge flow channel 20 in various ways through the electro-pneumatic proportional valves 33 and 35 .

[0046] When a normally closed (NC) electro-pneumatic proportional valve 33 is provided in the variable throttling mechanism 30, a normally open (NO) electromagnetic on-off valve 34 is configured in parallel with the electro-pneumatic proportional valve 33. Thus, even if the power supply to the electro-pneumatic proportional valve 33 and the electromagnetic on-off valve 34 stops accompanying the stop of the driving source, the compressed gas in the receiving container 60 can continue to be discharged through the discharge flow channel 20 after the cooling operation stops by opening the electromagnetic on-off valve 34.

[0047] In addition, in the case where the variable throttling mechanism 30 is composed of a normally open (NO type) electro-pneumatic proportional valve 35, if the power supply to the electro-pneumatic proportional valve 35 stops as the driving source stops, the electro-pneumatic proportional valve 35 opens to the maximum opening and discharges the compressed gas in the receiving container 60. Therefore, even if an electromagnetic on-off valve is not provided in parallel with the electro-pneumatic proportional valve 35, the compressed gas in the receiving container 60 can continue to be discharged after the driving source stops, so that the pressure in the receiving container 60 can be reduced to the atmospheric pressure P0. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is an explanatory diagram of the compressor of Example 1. Figure 2 This is a timing chart showing the operation of each part of the compressor of the first embodiment after the normal operation (unloaded operation) passes through the cooling operation and the engine is stopped. Figure 3 This is an explanatory diagram of the compressor of Example 2. Figure 4 This is a timing chart showing the operation of each part of the compressor of the second embodiment after the normal operation (unloaded operation) passes through the cooling operation and the engine is stopped. Figure 5 This is a timing chart showing the operation of each part of the compressor of the third embodiment after the normal operation (unloaded operation) passes through the cooling operation and the engine is stopped. Figure 6 This is an explanatory diagram of the compressor of Example 4. Figure 7 This is a timing chart showing the operation of each part of the compressor of the fourth embodiment after the normal operation (unloaded operation) passes through the cooling operation and the engine is stopped. Figure 8 This is an explanatory diagram of a conventional compressor (similar to that of Patent Document 1). Figure 1 correspond). DETAILED DESCRIPTION

[0049] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0050] In addition, in the embodiments described below, the compressor of the present invention is illustrated as an engine-driven compressor having an engine as a driving source, but the structure of the compressor of the present invention can also be applied to a motor-driven compressor having a driving source other than an engine, such as a motor as a driving source.

[0051] 1. Example 1 (Overall structure of engine-driven compressor) Figure 1 Reference numeral 1 in the figure denotes an engine-driven compressor according to the present invention. The engine-driven compressor 1 includes a compressor body 40, an engine (not shown) that drives the compressor body 40, and a receiving container 60 that stores compressed gas discharged from the compressor body 40. The compressed gas discharged from the compressor body 40 is stored in the receiving container 60 and then supplied to an air working machine (not shown) connected to a service valve 66 via a pressure regulating valve 61.

[0052] The aforementioned compressor body 40 is an oil-cooled screw compressor that compresses the compressed gas together with the lubricating oil used for lubrication, cooling and sealing. It is constructed to be able to introduce the compressed gas ejected from the compressor body 40 as a gas-liquid mixed fluid mixed with lubricating oil into the receiving container 60 through the ejection flow channel 62, and separate the compressed gas and the lubricating oil in the receiving container 60.

[0053] The lubricating oil separated and recovered in the receiving container 60 is squeezed out by the pressure in the receiving container 60 and supplied to the compressor body 40 through the oil supply passage 64 including the oil cooler 63 and the oil filter 65 .

[0054] (Inhalation adjustment device) The engine driven compressor 1 constructed as described above is provided with an intake air adjustment device 10 that controls the intake air amount of the compressor body 40 so as to stably supply compressed gas to the consumer side even if the consumption amount of compressed gas on the consumer side varies.

[0055] The intake adjustment device 10 is composed of an intake adjustment valve 11 for controlling the opening and closing of the intake port of the compressor body 40, a control flow channel 12 connecting the closed valve pressure receiving chamber 113 of the intake adjustment valve 11 and the receiving container 60, and a pressure regulator 13 for controlling the opening and closing of the control flow channel 12 according to the pressure in the receiving container 60, and is provided with a release flow channel 14, which discharges the compressed gas in the closed valve pressure receiving chamber 113 of the intake adjustment valve 11 via a throttling portion 15.

[0056] The engine-driven compressor 1 of the present invention is provided with a small suction flow path (not shown) that allows a relatively small amount of compressed gas to be introduced into the compressor body 40 even when the intake regulating valve 11 is closed. This allows the pressure within the receiving container 60 to be maintained at a predetermined unloading operating pressure P1 during unloading operation, even when compressed gas is continuously discharged through the release flow path 14.

[0057] Various structures can be used as the structure of the small suction flow path (not shown), but for example, a drilled hole can be provided that passes through the valve core of the intake adjustment valve 11, and the drilled hole can be used as the aforementioned small suction flow path (not shown). In addition, when the intake adjustment valve 11 is closed, the valve is not completely closed but maintained in a slightly open state, and the gap can be used as the small suction flow path.

[0058] By providing such a small suction flow path (not shown), a small amount of compressed gas is introduced from the compressor body 40 into the receiving container 60 even during unloaded operation with the intake regulating valve 11 closed.

[0059] Therefore, the flow rate of the compressed gas passing through the control flow passage 12 is adjusted so that the pressure in the receiving container 60 is balanced at the unloading operation pressure P1. In this way, the pressure in the receiving container 60 during the unloading operation can be maintained at the unloading operation pressure P1.

[0060] In a configuration where the drive source is an engine as in the compressor (engine-driven compressor) 1 of this embodiment, the rotational speed of the engine may be varied in accordance with the opening and closing operation of the intake regulating valve 11 provided in the intake regulating device 10 .

[0061] In this case, it is preferred to set the engine rotation speed during unloading operation and cooling operation with the intake regulating valve 11 in the closed state, that is, the no-load rotation speed, to a low rotation speed lower than the engine rotation speed during full-load operation with the intake regulating valve 11 fully open, that is, the full-load rotation speed, so as to reduce the load of the engine during unloading operation and cooling operation and reduce fuel consumption.

[0062] (Discharge channel and variable throttle mechanism) The engine-driven compressor 1 of the present invention is configured such that even if a stop command is input by operating a power switch (not shown) provided on a control panel (not shown) or the like, the engine does not stop immediately. Instead, the engine performs a predetermined cooling operation, and then stops. The cooling operation is performed by operating the engine and the compressor body 40 while the aforementioned intake regulating valve 11 is closed and the compressed gas in the receiving container 60 is discharged to reduce the pressure in the receiving container 60.

[0063] In this manner, in order to enable cooling operation in a state where the compressed gas in the receiving container 60 is discharged to reduce the pressure, the receiving container 60 is connected to one end of the discharge flow path 20 for discharging the compressed gas in the receiving container 60 .

[0064] Furthermore, the discharge flow path 20 is provided with a variable throttle mechanism 30 that changes the flow area of ​​the discharge flow path 20 , thereby varying the flow rate of the compressed gas and changing the pressure in the receiving container 60 .

[0065] In this embodiment, in order to use the compressed gas discharged through the discharge flow channel 20 as the working pressure for closing the intake regulating valve 11 during cooling operation, the other end of the discharge flow channel 20 is connected to the valve closing pressure receiving chamber 113 of the intake regulating valve 11.

[0066] With this configuration, during cooling operation, compressed gas within the receiving container 60 is exhausted via the discharge flow passage 20, the valve-closing pressure-receiving chamber 113 of the intake air regulating valve 11, and the relief flow passage 14. Consequently, the pressure within the receiving container 60 can be reduced to a pressure lower than the unloading operating pressure P1. Furthermore, even after the pressure regulator 13 closes the control flow passage 12 due to the pressure drop within the receiving container 60, operating pressure can be introduced into the valve-closing pressure-receiving chamber 113 of the intake air regulating valve 11 via the discharge flow passage 20, thereby maintaining the intake air regulating valve 11 in the closed state.

[0067] As described above, in this embodiment, the other end of the discharge flow passage 20 is connected to the valve-closing pressure-receiving chamber 113 of the intake air regulating valve 11 in order to close the intake air regulating valve 11 during cooling operation. However, the structure of the engine-driven compressor 1 of the present invention is not limited to this structure. Alternatively, a structure may be provided separately from the discharge flow passage 20 for closing the intake air regulating valve 11 during cooling operation, and the other end of the discharge flow passage 20 may be opened to the atmosphere without passing through the valve-closing pressure-receiving chamber 113 of the intake air regulating valve 11.

[0068] exist Figure 1 In the illustrated embodiment, the aforementioned discharge flow channel 20 is composed of a main flow channel 21 whose one end is connected to the receiving container 60, a manifold 22 connected to the other end of the main flow channel 21, and branch flow channels 23 and 24 that branch from the manifold 22 into two paths and are connected to the closed valve pressure receiving chamber 113 of the intake regulating valve 11.

[0069] A first electromagnetic on-off valve 31 having a first bore diameter is provided in one of the branch flow passages 23 and 24 provided in the discharge flow passage 20, and a second electromagnetic on-off valve 32 having a second bore diameter is provided in the other branch flow passage 24. The first and second electromagnetic on-off valves 31, 32 arranged in parallel form a variable throttle mechanism 30 that varies the flow area of ​​the discharge flow passage 20.

[0070] That is, the first electromagnetic on-off valve 31 and the second electromagnetic on-off valve 32 arranged in the aforementioned branch flow channels 23, 24 function as a "throttling part" that narrows the flow channel area of ​​each branch flow channel 23, 24, and the "drilling diameter" indicating the inner diameter of the flow channel formed in the main body of the first electromagnetic on-off valve 31 and the second electromagnetic on-off valve 32 corresponds to the flow channel area of ​​the electromagnetic on-off valve 31, 32 serving as the aforementioned "throttling part".

[0071] Furthermore, in the case where the first electromagnetic on-off valve 31 and the second electromagnetic on-off valve 32 are arranged in parallel, Figure 1 With the illustrated configuration, the flow channel area of ​​the discharge channel 20 can be varied to zero (zero: fully closed), a first flow channel area O1 corresponding to the first bore diameter, a second flow channel area O2 corresponding to the second bore diameter, and the total area (O1 + O2) of the first and second flow channel areas, when both the first and second electromagnetic on-off valves 31 and 32 are closed, only the first and second electromagnetic on-off valves 31 and 32 are open, and both are open. By varying these flow channel areas, the pressure within the receiving container 60 can be varied.

[0072] In the present embodiment, the first flow passage area O1 corresponding to the first bore diameter is formed to be a flow passage area capable of reducing the pressure in the receiving container 60 to a stable pressure P3 (for example, 0.3 MPa) and maintaining it at the stable pressure P3, and the second flow passage area O2 corresponding to the second bore diameter is formed to be a flow passage area capable of reducing the pressure in the receiving container 60 to a lower limit stable pressure P4 (for example, 0.1 MPa) and maintaining it at the lower limit stable pressure P4. The stable pressure P3 is a pressure lower than the pressure before the start of the cooling operation (the unloading operation pressure P1) and is a pressure at which oil can be stably supplied to the compressor body. The lower limit stable pressure P4 is a pressure lower than the stable pressure P3 (for example, 0.3 MPa) and higher than the atmospheric pressure P0 (0 MPa) and is a pressure at which the compressor body 40 and the engine are not reversed when the engine is stopped.

[0073] In this embodiment, a normally closed (NC) electromagnetic on-off valve is used as the first electromagnetic on-off valve 31, and a normally open (NO) electromagnetic on-off valve is used as the second electromagnetic on-off valve 32. After the engine stops, the second electromagnetic on-off valve 32 is opened even when the power to the first and second electromagnetic on-off valves 31 and 32 is stopped. Therefore, even if the engine is stopped when the pressure in the receiving container 60 is at the lower limit stable pressure P4, the pressure in the receiving container 60 can be reduced to atmospheric pressure P0 by continuing to discharge the compressed gas in the receiving container 60 after the engine stops.

[0074] (Control device) The engine-driven compressor 1 of the present invention constructed as described above is provided with a control device 70 composed of an electronic control device such as a microcontroller. The control device 70 is configured to control the operation of the first electromagnetic on-off valve 31 and the second electromagnetic on-off valve 32 constituting the variable throttling mechanism 30, thereby changing the flow channel area of ​​the discharge flow channel 20 and changing the pressure in the receiving container 60 during cooling operation.

[0075] In the present invention, the cooling operation is divided into a stop preparation period, which is a period immediately before the engine is stopped, and a main operation period, which is a period from the start of the cooling operation to the stop preparation period (see Figure 2), by causing the control device 70 to control the action of the variable throttle mechanism 30, the pressure in the receiving container 60 is reduced from the unloading operation pressure P1 to the stable pressure P3 and maintained at the stable pressure P3 during the main operation period. The stable pressure P3 is a pressure that is a predetermined amount lower than the unloading operation pressure P1 and is a pressure that can stably supply oil to the compressor body 40. During the stop preparation period, the pressure in the receiving container 60 is reduced from the stable pressure P3 to a lower limit stable pressure P4. The lower limit stable pressure P4 is a pressure that is lower than the stable pressure P3 and higher than the atmospheric pressure P0, and is a pressure that does not cause the compressor body 40 and the engine to reverse when the engine stops. Thereafter, the engine is stopped and the cooling operation is terminated.

[0076] By configuring in this manner, during the main operation period of the cooling operation, the compressor body is stably supplied with oil, thereby preventing sintering, etc. On the other hand, by reducing the pressure in the receiving container 60 to the lower limit stable pressure P4 during the stop preparation period immediately before stopping the engine, the compressor body and the engine are prevented from reversing when the engine is stopped, and deterioration of the oil seal of the compressor body and the fan belt of the engine caused by the reversal is prevented.

[0077] Furthermore, in this embodiment, by setting a reference pressure P2 (for example, 0.5 MPa) as a pressure lower than the unloading operation pressure P1 and higher than the stable pressure P3 (for example, 0.3 MPa) by a predetermined amount, and in the aforementioned main operation period, the flow channel area of ​​the discharge flow channel 20 is changed in such a manner that the pressure reduction rate when the pressure in the receiving container 60 decreases from the unloading operation pressure P1 to the reference pressure P2 is higher than the pressure reduction rate when the pressure decreases from the reference pressure P2 to the stable pressure P3, so that after the cooling operation starts, the back pressure of the compressor body 40 can be rapidly reduced to the reference pressure P2, thereby reducing the load applied to the compressor body 40 and then to the engine as soon as possible.

[0078] (Action description) Reference Figure 2 The timing chart shown explains the operation of each component during the cooling operation and before and after the start of the cooling operation in the engine-driven compressor 1 of the present invention configured as described above.

[0079] When stopping the engine-driven compressor 1, the air compressor equipment (not shown) connected to the service valve 66 of the engine-driven compressor 1 is stopped beforehand, and the consumption of compressed gas on the consumer side is stopped. Consequently, the pressure within the receiving container 60 rises above the operating pressure of the pressure regulator 13 provided in the control flow passage 12, resulting in an unloaded operation state in which the intake port of the compressor body 40 is closed by the intake regulating valve 11.

[0080] Thus, during the unloading operation before the start of the cooling operation, the control device 70 de-energizes (opens) the normally closed (NC) first electromagnetic on-off valve and energizes (opens) the normally open (NO) second electromagnetic on-off valve. Consequently, both the first and second electromagnetic on-off valves 31 and 32 are closed, preventing the compressed gas in the receiving container 60 from being discharged through the discharge flow path 20 (T0).

[0081] In this state, when a power switch (not shown) provided on an operating panel (not shown) or the like of the engine-driven compressor 1 is turned off, a main operation period (T1) of the cooling operation is started.

[0082] When the cooling operation starts, the control device 70 starts energizing (turning on) the first electromagnetic on-off valve 31 and de-energizing (turning off) the second electromagnetic on-off valve ( T1 ).

[0083] The first electromagnetic on-off valve 31 , which has a small bore diameter and is of the normally closed (NC) type, can open even when there is a relatively large pressure difference between the primary and secondary sides. When power is first supplied, the first electromagnetic on-off valve 31 opens immediately ( T1 ).

[0084] Therefore, during the unloading operation, the pressure in the receiving container 60, which is maintained at the predetermined unloading operation pressure P1 only by discharging compressed gas from the control flow channel 12 of the intake adjustment device 10, cannot maintain the pressure before the start of the cooling operation (unloading operation pressure P1) due to the increase in the flow channel area caused by the opening of the first electromagnetic on-off valve 31, but begins to decrease (T1-T2).

[0085] On the other hand, since a relatively large valve core is provided in the second electromagnetic on-off valve 32 of the normally open (NO) type, which has a large bore diameter, a large pressure difference between the primary and secondary sides not only applies a large force in the direction of seating the valve core on the valve seat (valve closing direction), but also since the normally open (NO) second electromagnetic on-off valve 32 is opened only by the force of the return spring, the force to separate the valve core from the valve seat is weak.

[0086] As a result, when the pressure in the receiving container 60 is high and the pressure difference between the primary and secondary sides is large, the second electromagnetic on-off valve 32 cannot open immediately even if it is switched to non-energized (off). Instead, it opens only when the pressure in the receiving container 60 drops due to the opening of the first electromagnetic on-off valve 31 and the pressure difference between the primary and secondary sides decreases to the pressure difference at which the second electromagnetic on-off valve 32 can operate (T2).

[0087] Due to the opening of the second electromagnetic on-off valve 32, the flow channel area of ​​the discharge flow channel 20 becomes the total area (O1+O2) of the first flow channel area O1 corresponding to the drill hole diameter (first drill hole diameter) of the first electromagnetic on-off valve 31 and the second flow channel area O2 corresponding to the drill hole diameter (second drill hole diameter) of the second electromagnetic on-off valve 32, thereby increasing the pressure reduction rate in the receiving container 60, thereby reducing the back pressure of the compressor body 40 as soon as possible.

[0088] If the pressure in the receiving container 60 drops to a level lower than the operating start pressure of the pressure regulator 13 provided in the control flow channel 12, the compressed gas will no longer be introduced from the control flow channel 12 to the closed valve pressure receiving chamber 113 of the intake regulating valve 11. However, the compressed gas in the receiving container 60 will continue to be introduced to the closed valve pressure receiving chamber 113 of the intake regulating valve 11 through the discharge flow channel 20, so that the intake regulating valve 11 maintains the closed valve state even after the switching to the cooling operation.

[0089] Then, when the control device 70 receives a detection signal from the pressure sensor 25 provided in the manifold 22 that the pressure in the receiving container 60 has dropped to a reference pressure P2 (for example, 0.5 MPa), the control device 70 closes the second electromagnetic on-off valve 32 by de-energizing (off) the second electromagnetic on-off valve 32 and continues to energize (on) the first electromagnetic on-off valve 31 to maintain the first electromagnetic on-off valve 31 in the open state, thereby reducing the flow area of ​​the discharge flow path 20 to the first flow area O1 (T3) corresponding to the drill hole diameter of the first electromagnetic on-off valve 31.

[0090] By reducing the flow channel area of ​​the discharge flow channel 20 in this manner, although the pressure reduction rate in the receiving container 60 decreases, the pressure in the receiving container 60 continues to decrease until it reaches the stable pressure P3 and stabilizes at the stable pressure P3.

[0091] Thus, during the main operation period from the start of the cooling operation to the stop preparation period, the pressure in the receiving container 60 is above the stable pressure P3 at which lubricating oil can be stably supplied to the compressor body 40, thereby ensuring stable oil supply to the compressor body 40.

[0092] In this embodiment, the passage of a predetermined time (for example, 120 seconds) from the start of the cooling operation is set as the termination condition for the aforementioned main operation period, and this condition is stored in the control device 70. Then, when the predetermined time (T4) has elapsed, the control device 70 de-energizes both the first and second electromagnetic on-off valves 31 and 32, closing the normally closed (NC) first electromagnetic on-off valve 31 and opening the normally open (NO) second electromagnetic on-off valve 32, thereby transitioning to the stop preparation period.

[0093] In this embodiment, the main operation period ends when a predetermined time (for example, 120 seconds) has elapsed since the start of the cooling operation. However, instead of this configuration, the main operation period may be terminated and the system transitioned to the stop preparation period if, for example, the temperature of the engine coolant and / or the temperature of the lubricating oil in the compressor body falls below a predetermined temperature. The main operation period termination conditions are not limited to the aforementioned conditions.

[0094] In this manner, by terminating the main operation period and shifting to the stop preparation period, the flow channel area of ​​the discharge flow channel 20 becomes the second flow channel area O2 corresponding to the bore diameter of the second electromagnetic on-off valve 32 .

[0095] The second flow channel area O2 serves as a flow channel area for reducing the pressure in the receiving container 60 to the lower limit stable pressure P4 and maintaining it at the lower limit stable pressure P4, and the stop preparation period is set to a time longer than the time required for the compressed gas in the receiving container 60 to be reduced from the stable pressure P3 to the lower limit stable pressure P4 when the flow channel area O2 is used to discharge the compressed gas in the receiving container 60 (in this embodiment, as an example, 60 seconds).

[0096] As a result, when the engine enters the stop preparation period and compressed gas begins to be discharged through the second electromagnetic on-off valve 32 provided in the discharge flow path 20, the pressure in the receiving container 60 decreases from the stable pressure P3 to the lower stable pressure P4 and is then maintained at the lower stable pressure P4. When the stop preparation period of a predetermined time (for example, 60 seconds) expires, the control device 70 stops the engine and ends the cooling operation (T5).

[0097] Furthermore, although lubricating oil is supplied to the compressor body 40 during the stop preparation period because the pressure within the receiving container 60 is maintained above atmospheric pressure P0, the same stable oil supply as during the main operation period cannot be ensured. Therefore, it is preferable to set the stop preparation period to be as short as possible. Therefore, for example, when the pressure sensor 25 provided in the manifold 22 detects that the pressure within the receiving container 60 has reached the aforementioned lower limit stable pressure P4, the control device 70 may stop the engine and terminate the cooling operation (stop preparation period), without being limited to the above-described configuration.

[0098] When the engine stops, the compressor body 40 stops, and the compressed gas in the receiving container 60 begins to flow into the compressor body 40. However, since the engine stops while the pressure in the receiving container 60 is low, the torque in the reverse direction generated by the compressed gas flowing into the compressor body 40 is small compared to the rotational resistance exerted on the screw rotor by the stopped engine. Specifically, since the pressure in the receiving container 60 drops to the lower limit stable pressure P4, which prevents the compressor body 40 and the engine from rotating reversely, deterioration of the oil seal associated with the reverse rotation of the compressor body 40 and deterioration of the fan belt due to slippage associated with the reverse rotation of the engine are effectively prevented.

[0099] When the engine stops, the power (ACC power supply) to the electrical components of the engine-driven compressor 1 is disconnected, de-energizing both the first and second electromagnetic on-off valves 31 and 32. Since the normally open (NO) second electromagnetic on-off valve 32 remains open, compressed gas continues to be discharged from the receiving container 60 through the discharge flow path 20 even after the engine stops, reducing the pressure in the receiving container 60 to atmospheric pressure P0.

[0100] By reducing the pressure in the receiving container 60 to the atmospheric pressure P0 in this manner, the next startup of the engine-driven compressor 1 can be smoothly performed.

[0101] 2. Example 2 In reference Figure 1 and Figure 2 In the engine-driven compressor 1 (Example 1) described above, an example is shown in which the aforementioned discharge flow path 20 is provided separately from the control flow path 12 provided in the intake adjustment device 10, and the variable throttle mechanism 30 is constituted by a first electromagnetic on-off valve 31 and a second electromagnetic on-off valve 32 provided in parallel in the discharge flow path 20.

[0102] In this regard, refer to the following Figure 3 and Figure 4 In the engine driven compressor 1 of the present embodiment (Example 2) described above, the variable throttle mechanism 30 is constituted by the electro-pneumatic proportional valve 33 and the electromagnetic on-off valve 34 provided in parallel in the discharge flow passage 20, and the electro-pneumatic proportional valve 33 is provided with a reference Figure 1 The function of the pressure regulator 13 provided in the control flow passage 12 of the engine driven compressor 1 is described, thereby removing the control flow passage 12 and the pressure regulator 13 from the structure.

[0103] Other structures and references Figure 1 The structure of the engine-driven compressor 1 described above is the same.

[0104] The discharge flow channel 20 of this embodiment (Example 2) is also the same as that of the reference Figure 1 As in the previously described embodiment (Example 1), the structure is such that the manifold 22 is connected to the other end of the main flow channel 21, one end of which is connected to the receiving container 60, and the branch flow channels 23 and 24 branched into two by the manifold 22 are connected to the valve closing pressure receiving chamber 113 of the intake regulating valve 11.

[0105] A normally closed (NC type) electro-pneumatic proportional valve 33 is provided in the branch flow channel 23 on one side of the branch flow channels 23 and a normally open (NO type) electromagnetic on-off valve 34 is provided in the branch flow channel 24 on the other side. The variable throttling mechanism 30 is formed by the electro-pneumatic proportional valve 33 and the electromagnetic on-off valve 34 arranged in parallel.

[0106] The normally closed (NC type) electro-pneumatic proportional valve 33 is configured to increase the flow path area according to the input signal from the fully closed state where no control signal is input. Figure 4 As shown, the structure is such that during cooling operation, the opening can be changed to "small" corresponding to the first flow channel area O1, "medium" corresponding to the second flow channel area O2, and "large" corresponding to the total area of ​​the first flow channel area O1 and the second flow channel area O2.

[0107] In this regard, a normally open (NO type) electromagnetic on-off valve is provided in the branch flow channel 24 on the other side as the electromagnetic on-off valve 34, which can close the branch flow channel 24 on the other side when the electromagnetic on-off valve 34 is energized (connected), and open the branch flow channel 24 on the other side when the electromagnetic on-off valve 34 is not energized (disconnected).

[0108] The bore diameter of the electromagnetic on-off valve 34 is not particularly limited, and electromagnetic on-off valves 34 with various bore diameters may be used. As an example, in this embodiment, an electromagnetic on-off valve 34 with a bore diameter corresponding to the second flow channel area O2 is used.

[0109] The operation of the variable throttle mechanism 30 constructed as described above is controlled by a control device 70 composed of an electronic control device such as a microcontroller.

[0110] The following reference Figure 4 The timing chart shown illustrates the state of control of each component by the control device 70.

[0111] In either the normal operation state before the start of the cooling operation or the cooling operation state, while the engine-driven compressor 1 is operating, the control device 70 sets the normally open (NO type) electromagnetic on-off valve 34 to the energized (on) state and maintains the other branch flow channel 24 in the discharge flow channel 20 in the closed state (T0).

[0112] On the other hand, when the engine driven compressor 1 is in the unloaded operation state before the cooling operation, the control device 70 sets the opening of the electro-pneumatic proportional valve 33 to a relatively small opening (at a pressure of 100°C) that can maintain the pressure in the receiving container 60 at the pressure before the start of the cooling operation (unloaded operation pressure P1). Figure 4 The compressed gas is introduced into the valve closing pressure receiving chamber 113 of the intake regulating valve 11 through one branch flow passage 23, thereby closing the intake regulating valve 11 (T0).

[0113] When the power switch provided on the operating panel of the engine-driven compressor is turned off from this state, the cooling operation starts, and the control device 70 changes the opening degree of the electro-pneumatic proportional valve 33 to “large” ( T1 ).

[0114] As a result, the pressure in the receiving container 60 begins to drop rapidly from the unloading operation pressure P1.

[0115] Upon receiving a detection signal from the pressure sensor 25 indicating that the pressure in the receiving container 60 has dropped to the reference pressure P2 , the control device 70 reduces the opening of the electro-pneumatic proportional valve 33 to “small” ( T3 ).

[0116] This "small" opening becomes an opening corresponding to the flow path area O1 that reduces the pressure in the receiving container 60 to the stable pressure P3 and maintains it at the stable pressure P3. Therefore, although the pressure reduction rate in the receiving container 60 slows down, it further reduces from the reference pressure P2 to the stable pressure P3 and maintains it at the stable pressure P3, thereby ensuring a stable supply of lubricating oil to the compressor body 40.

[0117] When a predetermined time (for example, 120 seconds) has passed since the start of the cooling operation (T4), the control device 70 changes the opening of the electro-pneumatic proportional valve 33 to "medium", and the cooling operation shifts from the main operation period to the stop preparation period.

[0118] Furthermore, in this embodiment, the timing for transitioning from the main operation period to the stop preparation period is set to occur when a predetermined time (for example, 120 seconds) has elapsed since the start of the cooling operation. However, instead of this configuration, for example, the transition from the main operation period to the stop preparation period may be conditioned on the temperature of the engine coolant and / or the temperature of the lubricating oil in the compressor body falling below a predetermined temperature. The transition conditions are not limited to the aforementioned example.

[0119] The opening degree of the electro-pneumatic proportional valve 33 during the stop preparation period, i.e., the "medium" opening degree, corresponds to the second flow passage area O2, which reduces the pressure within the receiving container 60 to and maintains it at the lower regulated pressure limit P4. Consequently, the pressure within the receiving container 60 begins to decrease from the regulated pressure P3 to and maintains it at the lower regulated pressure limit P4. Once the stop preparation period has elapsed for a predetermined period (for example, 60 seconds), the control device 70 stops the engine, terminating the cooling operation (T5).

[0120] When the engine stops, the compressor body 40 stops rotating, and the compressed gas in the receiving container 60 flows toward the compressor body 40. However, since the pressure in the receiving container 60 drops to the lower limit stable pressure P4, which prevents the compressor body 40 and the engine from rotating in reverse even with such compressed gas inflow, deterioration of the oil seal associated with the reverse rotation of the compressor body 40 and deterioration of the fan belt due to slippage of the fan belt associated with the reverse rotation of the engine are appropriately prevented.

[0121] By stopping the engine, the power supply (ACC power supply) to the electrical components provided in the engine-driven compressor 1 is disconnected. If the electromagnetic on-off valve 34 provided in the other branch flow passage 24 becomes de-energized (opened), the normally open (NO type) electromagnetic on-off valve 34 opens the other branch flow passage 24.

[0122] As a result, even if the normally closed (NC) electro-pneumatic proportional valve 33 is de-energized (off) and fully closed, the pressure in the receiving container 60 can be reduced to atmospheric pressure P0 by discharging the compressed gas in the receiving container 60 through the other branch flow path 24 .

[0123] 3. Example 3 Above, in reference Figure 3 and Figure 4 In the embodiment described (Example 2), the following structure is described: the normally open (NO type) electromagnetic on-off valve 34 provided in the other branch flow passage 24 is configured to maintain a closed valve state during the operation of the engine-driven compressor 1, regardless of normal operation or cooling operation, and is opened only after the power supply is stopped when the engine stops. The flow passage area of ​​the discharge flow passage 20 during cooling operation is changed only by adjusting the opening of the electro-pneumatic proportional valve 33.

[0124] In this regard, Figure 5 The timing diagram shown shows the Figure 3In the engine-driven compressor 1 of the same structure, the control device 70 stops (disconnects) the power supply to the normally closed (NC) electro-pneumatic proportional valve 33 and the power supply to the normally open (NO) electromagnetic on-off valve 34 at the timing (T4) when the main operation period shifts to the stop preparation period, thereby fully closing the electro-pneumatic proportional valve 33 and opening the electromagnetic on-off valve 34. As a result, the compressed gas in the receiving container 60 during the stop preparation period is discharged through the electromagnetic on-off valve 34 (the other branch flow channel 24). The other operations are the same as those in the reference. Figure 4 The embodiment described (Example 2) is the same.

[0125] As described above, the bore diameter of the electromagnetic on-off valve 34 provided in the other branch flow passage 24 corresponds to the second flow passage area O2, which reduces the pressure in the receiving container 60 to and maintains it at the lower stabilization pressure P4. Therefore, during the stop preparation period, by fully closing the electro-pneumatic proportional valve 33 to close one branch flow passage 23 and discharging the compressed gas in the receiving container 60 through the other branch flow passage 24 equipped with the electromagnetic on-off valve 34, the pressure in the receiving container 60 can be reduced to and stabilized at the lower stabilization pressure P4.

[0126] Furthermore, even if the control device 70 stops the engine and disconnects the ACC power supply due to expiration of the stop preparation period, the normally open (NO type) electromagnetic on-off valve 34 continues to be maintained in the open state. Therefore, the compressed gas in the receiving container 60 continues to be discharged even after the engine stops, thereby reducing the pressure in the receiving container 60 to the atmospheric pressure P0.

[0127] 4. Example 4 In reference to the aforementioned Figure 3 In the described embodiments (Examples 2 and 3), a normally closed (NC) electro-pneumatic proportional valve 33 is employed as the electro-pneumatic proportional valve provided in the variable throttle mechanism 30. Furthermore, a normally open (NO) electromagnetic on-off valve 34 is provided in parallel with the electro-pneumatic proportional valve 33. This configuration allows for discharge of compressed gas from the receiving container 60 after the engine is stopped and the cooling operation is completed, via the other branch flow path 24 opened by the electromagnetic on-off valve 34.

[0128] In this regard, Figure 6 and Figure 7 In the present embodiment (Example 4) shown, a normally open (NO type) electro-pneumatic proportional valve 35 is provided as the electro-pneumatic proportional valve, so that the flow area of ​​the discharge flow path 20 during the cooling operation can be changed by the electro-pneumatic proportional valve 35, and the compressed gas in the receiving container 60 can also be discharged after the engine is stopped and the cooling operation is ended through the electro-pneumatic proportional valve 35.

[0129] That is, in Figure 6and Figure 7 In the illustrated embodiment (Example 4), the variable throttle mechanism 30 for making the flow path area of ​​the discharge flow path 20 variable is constituted by only the normally open (NO type) electro-pneumatic proportional valve 35 .

[0130] Under this structure, when the engine-driven compressor 1 is in an unloaded operation state before starting the cooling operation, the control device 70 is in a state of slightly opening the electro-pneumatic proportional valve 35 with an opening between "fully closed" and "small" to introduce working pressure into the closed valve pressure receiving chamber 113 of the intake regulating valve 11.

[0131] In this state, if the power switch is turned off to instruct the engine driven compressor 1 to stop, the cooling operation starts, and the control device 70 sets the opening of the electro-pneumatic proportional valve 35 to "large" to rapidly reduce the pressure in the receiving container 60 (T1).

[0132] When the control device 70 receives a detection signal (T3) from the pressure sensor 25 indicating that the pressure in the receiving container 60 has dropped to the reference pressure P2, the control device 70 reduces the opening of the electro-pneumatic proportional valve 35 to "small" corresponding to the first flow channel area O1, thereby further reducing the pressure in the receiving container 60 from the reference pressure P2 and stabilizing it at the stable pressure P3.

[0133] Then, after a predetermined time (for example, 120 seconds) has elapsed since the start of the cooling operation (T4), the control device 70 changes the opening of the electro-pneumatic proportional valve 35 to "medium" corresponding to the second flow passage area O2, shifting the cooling operation from the main operation phase to the stop preparation phase. Simultaneously, the pressure within the receiving container 60 is reduced from the steady pressure P3 to the lower steady pressure limit P4. After the predetermined time (for example, 60 seconds) of the stop preparation phase has elapsed, the control device 70 stops the engine, terminating the cooling operation (T5).

[0134] When the engine stops and the ACC power supply is disconnected, if the power to the electro-pneumatic proportional valve 35 is stopped, the electro-pneumatic proportional valve 35 becomes "large (fully open)", so that the compressed gas in the receiving container 60 continues to be discharged even after the engine stops, and the pressure in the receiving container 60 can be reduced to atmospheric pressure P0. Description of Reference Numerals

[0135] 1 (Engine-driven) compressor 10 Inhalation adjustment device 11 Intake adjustment valve 113 (Suction regulating valve) closed valve pressure chamber 12 Control flow channel 13. Pressure regulator 14 Release flow channel 15 Throttle 20 Discharge channel 21 Main channel 22 Manifold 23 (One side) branch channel 24 (Other side) branch channel 25 Pressure Sensor 30 Variable throttle mechanism 31 First electromagnetic on-off valve (NC type) 32 Second electromagnetic on-off valve (NO type) 33 Electro-pneumatic proportional valve (NC type) 34 Solenoid on-off valve (NO type) 35 Electro-pneumatic proportional valve (NO type) 40 Compressor body 60 receiving container 61 Pressure regulating valve 62 ejection channel 63 Oil cooler 64 oil supply channel 65 Oil filter 66 Service Valve 70 Control Device 300 Engine Driven Compressor 310 Inhalation adjustment device 311 Intake adjustment valve 311a Closed valve pressure chamber 312 Control Flow Channel 313 Pressure Regulator 314 Release flow channel 315 Throttling Unit 323, 324 bypass flow channel 331, 332 electromagnetic on-off valve 340 compressor body 360 receiving container 363 Oil Cooler 364 oil supply channel 365 Oil Filter 366 Service Valve 365 Oil filter.

Claims

1. A method for controlling the operation of a compressor, the compressor comprising: Oil-cooled compressor body; a driving source for driving the compressor body; a receiving container for introducing the compressed gas ejected from the compressor body; an oil supply passage, connecting the receiving container with the compressor body and utilizing the pressure in the receiving container to supply oil to the compressor body; a discharge flow channel for discharging the compressed gas in the receiving container; as well as The intake regulating valve opens and closes the intake port of the compressor body. The compressor performs unloading operation and cooling operation. The unloading operation is performed in a state where the intake regulating valve is closed and the pressure in the receiving container is maintained at a predetermined unloading operation pressure. The cooling operation is performed before stopping the driving source, with the intake regulating valve closed and the compressed gas discharged through the discharge flow path to reduce the pressure in the receiving container. The operation control method of the compressor is characterized in that: When the intake regulating valve is closed, a small amount of compressed gas can be introduced into the compressor body. The cooling operation period is divided into a stop preparation period, which is a period immediately before the drive source is stopped, and a main operation period, which is a period from the start of the cooling operation to the stop preparation period. By changing the flow channel area of ​​the discharge flow channel, During the main operation period, the pressure in the receiving container is reduced to a stable pressure, which is a pressure lower than the unloading operation pressure by a predetermined amount and is a pressure at which oil can be stably supplied to the compressor body. During the stop preparation period, the pressure in the receiving container is reduced to a lower limit stable pressure, which is a pressure lower than the stable pressure and higher than atmospheric pressure, and is a pressure at which the compressor body does not rotate inversely when the driving source stops. Thereafter, the driving source is stopped, and the cooling operation is terminated.

2. The operation control method of the compressor according to claim 1, characterized in that: In the main operation period, after the pressure in the receiving container is reduced to the stable pressure, the stable pressure is maintained until the end of the main operation period.

3. The operation control method of the compressor according to claim 1, characterized in that: setting a reference pressure, the reference pressure being a pressure lower than the unloading operation pressure and higher than the stable pressure by a predetermined amount, The flow channel area of ​​the discharge flow channel in the main operation period is changed in such a manner that a pressure reduction rate when the pressure in the receiving container decreases from the unloading operation pressure to the reference pressure is higher than a pressure reduction rate when the pressure in the receiving container decreases from the reference pressure to the stable pressure.

4. The operation control method of a compressor according to any one of claims 1 to 3, characterized in that: After the cooling operation is completed, the compressed gas continues to be discharged from the discharge flow channel to reduce the pressure in the receiving container to atmospheric pressure.

5. A compressor comprising: Oil-cooled compressor body; a driving source for driving the compressor body; a receiving container for introducing the compressed gas ejected from the compressor body; an oil supply passage, connecting the receiving container with the compressor body and utilizing the pressure in the receiving container to supply oil to the compressor body; a discharge flow channel for discharging the compressed gas in the receiving container; as well as The intake regulating valve opens and closes the intake port of the compressor body. The compressor performs unloading operation and cooling operation. The unloading operation is performed in a state where the intake regulating valve is closed and the pressure in the receiving container is maintained at a predetermined unloading operation pressure. The cooling operation is performed before stopping the driving source, with the intake regulating valve closed and the compressed gas discharged through the discharge flow path to reduce the pressure in the receiving container. The compressor is characterized in that The compressor is provided with: a small intake flow passage for introducing a small amount of compressed gas into the compressor body when the intake regulating valve is closed; A variable throttle mechanism that changes the flow channel area of ​​the discharge flow channel; and a control device that controls the operation of the variable throttle mechanism and the drive source, and The cooling operation period is divided in advance into a stop preparation period, which is a period immediately before the drive source is stopped, and a main operation period, which is a period from the start of the cooling operation to the stop preparation period. The control device stores the end conditions of the main operation period and the stop preparation period, and controls the operation of the variable throttle mechanism and the drive source. The control device sets the flow channel area of ​​the discharge flow channel in the main operation period so that the pressure in the receiving container is reduced to a stable pressure, which is a pressure lower than the unloading operation pressure by a predetermined amount and is a pressure at which oil can be stably supplied to the compressor body. The control device sets the flow channel area of ​​the discharge flow channel in the stop preparation period so that the pressure in the receiving container is reduced to a lower limit stable pressure, which is a pressure lower than the stable pressure and higher than atmospheric pressure and is a pressure at which the compressor body is not reversed when the driving source stops. The control device then stops the driving source to end the cooling operation.

6. The compressor according to claim 5, characterized in that The control device controls the variable throttle mechanism during the main operation period so that the flow area of ​​the discharge flow path becomes a flow area that is maintained at the stable pressure after the pressure in the receiving container is reduced to the stable pressure.

7. The compressor according to claim 5, characterized in that A pressure detecting member is provided for detecting the pressure in the receiving container to be a reference pressure, wherein the reference pressure is a pressure lower than the unloading operation pressure and higher than the stable pressure by a predetermined amount. The control device controls the variable throttling mechanism during the main operation period in such a manner that the flow area after the reference pressure is detected changes relative to the flow area from the start of the cooling operation to the detection of the reference pressure by the pressure detection component, so that the pressure in the receiving container decreases at a higher pressure drop rate when the pressure decreases from the unloading operation pressure to the reference pressure than when the pressure decreases from the reference pressure to the stable pressure.

8. The compressor according to any one of claims 5 to 7, characterized in that: The variable throttle mechanism is configured to maintain the discharge flow path in an open state even after the cooling operation is completed.

9. The compressor according to any one of claims 5 to 7, characterized in that: The variable throttle mechanism is composed of a plurality of electromagnetic on-off valves having different bore diameters and arranged in parallel in the discharge flow path.

10. The compressor according to claim 8, characterized in that The variable throttle mechanism is composed of a plurality of electromagnetic on-off valves with different bore diameters arranged in parallel in the discharge flow channel. At least one of the electromagnetic on-off valves is a normally open electromagnetic on-off valve.

11. The compressor according to any one of claims 5 to 7, characterized in that: The variable throttle mechanism includes an electro-pneumatic proportional valve in its structure.

12. The compressor according to claim 8, characterized in that The variable throttle mechanism includes a normally closed electro-pneumatic proportional valve and a normally open electromagnetic on-off valve, which are arranged in parallel in the discharge flow path.

13. The compressor according to claim 8, characterized in that The variable throttle mechanism is composed of a normally open electro-pneumatic proportional valve provided in the discharge flow path.

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