JP6676961B2 - air compressor - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air compressor, and more particularly to an air compressor used for a pneumatic tool (a nailing machine or a screw driving machine) or the like, wherein a compressed air generating section and a compressed air generated by a compressed air generating section are used. And a tank for storing air.

  The air compressor has a compressed air generator and a tank that stores the compressed air generated by the compressed air generator. For example, the compressed air generating unit includes a power source, a piston reciprocally driven by a driving force output from the power source, a cylinder accommodating the piston reciprocally, and having a volume that changes with the reciprocation of the piston. ,including. An electric motor that outputs rotational driving force may be used as a power source. In this case, the rotational driving force output from the electric motor is converted into a reciprocating driving force by a conversion mechanism and transmitted to the piston.

  When the piston in the cylinder moves from the top dead center to the bottom dead center, the volume of the cylinder increases, the inside of the cylinder becomes negative pressure, and air is introduced into the cylinder. The air introduced into the cylinder is compressed by a piston moving from the bottom dead center to the top dead center in the cylinder, and the pressure is increased. The compressed air (high-pressure air) is sent to a tank via a predetermined pipe and is stored in the tank.

  According to Patent Document 1, when the power supply to the compressor body is turned off, the power stored in the storage battery in advance when the power is supplied is supplied to the notification means, and the notification means reduces the residual pressure in the air tank by the operator. An air compressor to be notified is described.

JP 2010-14057 A

  In an air compressor used for a pneumatic tool (a nail driving machine or a screw driving machine), soap water or the like is used to detect air leakage. Could not be confirmed.

  An object of the present invention is to provide an air compressor having a function of detecting an air leak.

  An air compressor according to the present invention includes a compressed air generation unit, an air tank that stores compressed air generated by the compressed air generation unit, a pressure sensor that detects an internal pressure of the air tank, and the compressed air generation unit. And a control unit for controlling. Further, in the air compressor of the present invention, based on a normal operation mode in which the compressed air generator is controlled so that the internal pressure of the air tank is maintained within a predetermined range, and a change in the internal pressure of the air tank. An arbitrary operation mode can be selected from a plurality of operation modes including an air leakage detection mode in which air leakage is detected. When the air leak detection mode is selected, the control unit obtains a first measurement value by measuring an internal pressure of the air tank, and a first predetermined time has elapsed since the acquisition of the first measurement value. Thereafter, the internal pressure of the air tank is measured again to obtain a second measurement value, and a difference value between the first measurement value and the second measurement value is compared with a first reference value, and the difference value is equal to the first reference value. If it is larger than the reference value, it is determined that there is air leakage. If the difference value is smaller than the first reference value, it is determined that there is no air leak.

  In one aspect of the present invention, when the air leak detection mode is selected, before acquiring the first measurement value, the internal pressure of the air tank is measured to acquire a pre-measurement value, Comparing the pre-measured value with a second reference value, and if the pre-measured value is greater than the second reference value, acquiring the first measured value; If the pressure is smaller than the reference value, the first measurement value is acquired after the internal pressure of the air tank is made higher than the second reference value by operating the compressed air generator.

  In another aspect of the present invention, the control unit activates the compressed air generation unit to set the internal pressure of the air tank higher than the second reference value, and after the second predetermined time elapses, the control unit performs 1 Obtain the measured value.

  In another aspect of the present invention, the control unit that has determined that there is an air leak reports the determination result by at least one of sound and light.

  In another aspect of the present invention, an LED controlled by the control unit is provided, and the control unit, which has determined that there is an air leak, turns on or blinks the LED to report the determination result.

  In another aspect of the present invention, a speaker controlled by the control unit is provided, and the control unit, which has determined that there is an air leak, causes the speaker to emit a notification sound and notifies the determination result.

  In another aspect of the present invention, at least one of the first reference value, the second reference value, and the first predetermined time can be changed.

  In another aspect of the present invention, the second predetermined time can be changed.

  In another aspect of the present invention, the motor that is the power source of the compressed air generator is not operated until the first predetermined time has elapsed.

  In another aspect of the present invention, the control unit controls the electromagnetic valve so as to prevent the compressed air from leaking from the air tank after notifying the determination result.

  In another aspect of the present invention, the first measured value and the second measured value are average values of pressure measured a plurality of times.

  In another aspect of the present invention, the air compressor includes a compressed air generator, an air tank that stores compressed air generated by the compressed air generator, a pressure sensor that detects an internal pressure of the air tank, A control unit that controls the compressed air generation unit. In this air compressor, an air leak is detected based on a normal operation mode in which the compressed air generation unit is controlled so that the internal pressure of the air tank is maintained within a predetermined range, and a change in the internal pressure of the air tank. An arbitrary operation mode can be selected from a plurality of operation modes including an air leak detection mode performed. When the air leak detection mode is selected, the control unit obtains a first measurement value by measuring an internal pressure of the air tank, and a first predetermined time has elapsed since the acquisition of the first measurement value. Later, the internal pressure of the air tank is measured again to obtain a second measured value, and the rate of change of the pressure between the first measured value and the second measured value is compared with a predetermined reference value. If the rate is larger than the reference value, it is determined that there is air leakage, and if the pressure change rate is smaller than the reference value, it is determined that there is no air leak.

  According to the present invention, an air compressor having a function of detecting an air leak is realized.

It is a figure showing appearance of an air compressor. It is a figure showing the internal structure of an air compressor. FIG. 3 is a diagram illustrating an operation panel. FIG. 3 is a diagram illustrating a configuration of a control unit. It is a figure which shows the change of the tank internal pressure at the time of normal operation mode selection. FIG. 7 is a diagram illustrating a control flow when an air leak detection mode is selected. It is a figure showing an example of a change of tank internal pressure at the time of air leak detection mode selection. FIG. 9 is a diagram illustrating another example of a change in the tank internal pressure when the air leak detection mode is selected. It is a figure showing an example of a use state of an air compressor.

  Hereinafter, an example of an embodiment of an air compressor of the present invention will be described. The air compressor according to the present embodiment is a reciprocating air compressor including a compressed air generation unit powered by an electric motor (hereinafter, “motor”). The application of the air compressor according to the present embodiment is not particularly limited, but is suitable for use as a supply source for supplying compressed air to an air tool for driving nails or screws into wood or the like by the pressure of compressed air. Hereinafter, the air compressor according to the present embodiment will be described in detail with reference to the drawings.

  As shown in FIG. 1, the air compressor 1 has a base 11 including a frame such as a frame and two parallel air tanks 10a and 10b connected to the frame. Legs 12 are attached to the lower surfaces of both ends of each of the air tanks 10a and 10b, and the air compressor 1 is placed at a desired installation location by the four legs 12. In addition, handles 13 are provided at both ends of the base 11, and an operator can carry the air compressor 1 by gripping the handles 13.

  As shown in FIG. 2, the base 11 has a compressed air generator 20 mounted thereon. The compressed air generation unit 20 includes a motor 21 as a power source, a crankcase 22, and two cylinders (a first cylinder 23A and a second cylinder 23B). Normally, the compressed air generator 20 is covered by the cover 14 shown in FIG.

  Referring to FIG. 2 again, the motor 21 includes a stator 21a, a rotor 21b incorporated inside the stator 21a, a rotating shaft (motor rotating shaft 21c) integrated with the rotor 21b, and a rotating position of the rotor 21b. It has a Hall element to detect. That is, the motor 21 is a DC brushless motor. The motor 21 is arranged outside the crankcase 22, but is fixed to a cover of the crankcase 22 and is integrated with the crankcase 22.

  The motor rotation shaft 21c penetrates the rotor 21b and protrudes on both axial sides of the rotor 21b. A protruding portion of the motor rotating shaft 21c protruding to one side in the axial direction of the rotor 21b penetrates through the crankcase 22, and is rotatably supported by a bearing provided on the crankcase 22.

  On the opposite side of the crankcase 22 from the motor 21, there is disposed a control unit 30 including a circuit board on which a semiconductor switching element for controlling the motor 21 by inverter is mounted. The control unit 30 is disposed so as to face the crankcase 22, and is fixed to the air tank 10b.

  The first cylinder 23A and the second cylinder 23B are provided on both sides of the crankcase 22. The first cylinder 23A and the second cylinder 23B are arranged at positions different by 180 degrees with respect to the rotation direction of the motor rotation shaft 21c. The first cylinder 23A houses the first piston 23a in a reciprocating manner. A second piston 23b is accommodated in 23B so as to be able to reciprocate.

  One end of a first connecting rod is pin-connected to the first piston 23a in order to convert the rotational movement of the motor rotation shaft 21c into a reciprocating movement of the first piston 23a, and the other end of the first connecting rod is It is rotatably connected to an eccentric cam mounted on the motor rotation shaft 21c. Further, one end of a second connecting rod is pin-connected to the second piston 23b in order to convert the rotational movement of the motor rotation shaft 21c into a reciprocating movement of the second piston 23b, and the other end of the second connecting rod is connected to the second piston 23b. Is rotatably connected to another eccentric cam mounted on the motor rotation shaft 21c. Therefore, in the following description, the motor rotation shaft 21c may be referred to as "crankshaft 21c". The rotational driving force output from the motor 21 is converted into a reciprocating driving force by a conversion mechanism including a crankshaft 21c, an eccentric cam, and a connecting rod (a first connecting rod, a second connecting rod), and the piston (the first piston 23a, It is transmitted to the second piston 23b).

  When the first piston 23a is driven in a direction to compress the upper chamber of the first cylinder 23A, the second piston 23b is driven in a direction to expand the upper chamber of the second cylinder 23B. On the other hand, when the second piston 23b is driven in a direction to compress the upper chamber of the second cylinder 23B, the first piston 23a is driven in a direction to expand the upper chamber of the first cylinder 23A.

  A buffer chamber is provided inside the cylinder head of each of the cylinders 23A and 23B. When the first piston 23a is driven in a direction to compress the upper chamber of the first cylinder 23A and the pressure of the air in the upper chamber becomes higher than a predetermined pressure, the reverse direction between the upper chamber of the first cylinder 23A and the buffer chamber is established. The stop valve is opened. Then, the air compressed by the first piston 23a is sent to the upper chamber of the second cylinder 23B via the first pipe 24 that connects the first cylinder 23A and the second cylinder 23B.

  When the second piston 23b is driven in the direction of compressing the upper chamber of the second cylinder 23B and the pressure of the air in the upper chamber becomes higher than a predetermined pressure, the reverse direction between the upper chamber of the second cylinder 23B and the buffer chamber is established. The stop valve is opened. Then, the air compressed by the second piston 23b is sent to and stored in the air tank 10a via the second pipe connecting the second cylinder 23B and the air tank 10a. The air tanks 10a and 10b communicate with each other via a third pipe. Therefore, the pressures in the air tanks 10a and 10b are kept uniform.

  Here, outside air is introduced into the upper chamber of the first cylinder 23A shown in FIG. That is, the first piston 23a compresses outside air, and the second piston 23b further compresses outside air (air) compressed by the first piston 23a. In other words, the first piston 23a is a first-stage low-pressure piston, and the second piston 23b is a second-stage high-pressure piston. The first cylinder 23A is a first-stage low-pressure cylinder, and the second cylinder 23B is a second-stage high-pressure cylinder. Thus, the air compressor 1 according to the present embodiment compresses air in two stages. Specifically, the first piston 23a generates compressed air of about 1.0 [MPa], and the second piston 23b generates compressed air of about 4.0 to 4.5 [MPa].

  As shown in FIG. 1, above the ends of the air tanks 10a and 10b, there are provided couplers 15a and 15b, which are outlets for compressed air. Further, pressure reducing valves 16a and 16b for adjusting the pressure of the compressed air are provided between the air tanks 10a and 10b and the couplers 15a and 15b, respectively. The pressure of the compressed air adjusted by the pressure reducing valves 16a, 16b is measured and displayed by pressure gauges 17a, 17b installed near the respective pressure reducing valves 16a, 16b.

  As shown in FIG. 2, the air tank 10a is provided with a safety valve 18a that automatically opens when the pressure in the air tanks 10a and 10b becomes higher than a predetermined pressure. On the other hand, a drain device 18b is provided in the air tank 10b, and when the drain device 18b is operated, the water in the air tanks 10a and 10b is discharged together with the compressed air. As shown in FIG. 1, an operation panel 19 is provided on an upper surface of the cover 14, and various kinds of information are transmitted to a control unit 30 (FIG. 2) via an input unit (not shown) provided on the operation panel 19. Command or instruction is input.

  During the operation of the air compressor 1, the temperatures of the compressed air generator 20 and the controller 30 shown in FIG. Therefore, the air compressor 1 is provided with two cooling fans (a first cooling fan 25a and a second cooling fan 25b) opposed to each other across the crankcase 22. The first cooling fan 25a is a cooling fan for mainly supplying cooling air to the compressed air generating unit 20, and is arranged at a position facing the crankcase 22 with the motor 21 interposed therebetween. The second cooling fan 25b is a cooling fan for mainly supplying cooling air to the control unit 30, and is disposed between the crankcase 22 and the control unit 30.

  Here, the air compressor 1 according to the present embodiment has a plurality of operation modes. The user can select an arbitrary operation mode from a plurality of operation modes of the air compressor 1. Specifically, the air compressor 1 has at least two operation modes, a “normal operation mode” and an “air leak detection mode”. As shown in FIG. 3, the operation panel 19 is provided with a mode switch 26. When the mode switch 26 is pressed, the normal operation mode is selected. When the mode changeover switch 26 is pressed for a long time (for example, when the state where the mode changeover switch 26 is pressed is continued for 5 seconds or more), the air leak detection mode is selected. In other words, when the mode switch 26 is pressed for a long time, the operation mode is switched from the normal operation mode to the air leak detection mode.

  As shown in FIG. 4, the control unit 30 includes a central processing unit (hereinafter, “CPU”) 31, a random access memory (hereinafter, “RAM”) 32, a read-only memory (hereinafter, “ROM”) 33, and a timer 34. Then, the compressed air generator 20 is controlled according to the operation mode selected as described above. The ROM 33 stores a control program for controlling the compressed air generator 20, and the RAM 32 is used for temporarily storing data and calculation results required for executing the control program.

  The air tank 10b is provided with a pressure sensor 35 for detecting the internal pressure of the air tank 10b. The pressure sensor 35 outputs an electric signal (detection signal) corresponding to the internal pressure of the air tank 10b to the control unit 30. As described above, the internal pressure of the air tank 10b and the internal pressure of the air tank 10a (FIG. 1) are kept equal. Therefore, in the following description, the internal pressure of the air tanks 10a, 10a is generically referred to as "tank internal pressure". That is, the pressure inside the tank is detected by the pressure sensor 35, and the detection result is input to the control unit 30. Normally, the pressure sensor 35 detects the tank internal pressure at a predetermined sampling cycle, and outputs a detection signal to the control unit 30. The pressure sensor 35 in the present embodiment detects the tank internal pressure every one second and outputs a detection signal to the control unit 30. The control unit 30 displays a numerical value indicating the tank internal pressure detected by the pressure sensor 35 on the display unit 27 provided on the operation panel 19.

  The control unit 30 controls the compressed air generation unit 20 based on the control program and according to the selected operation mode. Hereinafter, the control executed by the control unit 30 will be described separately when the normal operation mode is selected and when the air leak detection mode is selected.

(When normal operation mode is selected)
The control unit 30 shown in FIG. 4 controls the compressed air generation unit 20 so that the tank internal pressure is maintained within a predetermined range. Specifically, as shown in FIG. 5, the control unit 30 controls the compressed air generation unit so that the tank internal pressure is maintained between a predetermined lower limit (Pmin) and a predetermined upper limit (Pmax). 20 is controlled. When the compressed air stored in the air tanks 10a and 10b shown in FIG. 1 and the like is consumed, the tank internal pressure decreases. Therefore, the control unit 30 shown in FIG. 4 operates the compressed air generation unit 20 (motor 21) to generate the compressed air when the tank internal pressure decreases to the lower limit (Pmin). Thereafter, when the tank internal pressure rises to the upper limit (Pmax), the control unit 30 stops the compressed air generation unit 20 (motor 21) and stops the generation of compressed air. Thereafter, when the tank internal pressure again decreases to the lower limit value (Pmin), the control unit 30 operates the compressed air generation unit 20 (motor 21) again to restart the generation of the compressed air.

  As described above, when the normal operation mode is selected, the control unit 30 operates the compressed air generation unit 20 (motor 21) intermittently to reduce the tank internal pressure to the lower limit value (Pmin) and the upper limit value (Pmax). Keep between. In the present embodiment, the lower limit (Pmin) is set to 2.3 [MPa], and the upper limit (Pmax) is set to 4.3 [MPa]. Further, it is needless to say that the operation and stop timings of the compressed air generation unit 20 (motor 21) as described above are determined based on the detection result of the tank internal pressure by the pressure sensor 35.

(When air leak detection mode is selected)
When the air leak detection mode is selected, the control unit 30 shown in FIG. 4 executes the control flow for air leak detection shown in FIG. When the air leak detection mode is selected, the control unit 30 executes step 101. In step 101, the control unit 30 resets the count of the timer 34 shown in FIG. 4 and measures the tank internal pressure to acquire a measured value. Specifically, the control unit 30 stores the tank internal pressure detected by the pressure sensor 35 when the air leak detection mode is selected as a pre-measured value (P ₀ ) in the RAM 32.

Thereafter, the control unit 30 proceeds to step 102 shown in FIG. In step 102, the control unit 30 compares the pre-measured value (P ₀ ) with the second reference value (Ps). If the tank pressure is too low, it will be impossible or difficult to detect air leaks. Therefore, a second reference value (Ps) is set in advance as a reference value for determining whether or not air leak detection is possible. As shown in FIG. 5, the second reference value (Ps) in the present embodiment is set to a value larger than the lower limit (Pmin) and smaller than the upper limit (Pmax). In other words, the second reference value (Ps) in the present embodiment is a pressure higher than the lower limit (Pmin) and lower than the upper limit (Pmax). However, the second reference value (Ps) may be set to a value smaller than the lower limit (Pmin) depending on an object for which air leakage is to be measured.

FIG. 6 is referred to again. When the control unit 30 determines in step 102 that the pre-measured value (P ₀ ) is larger than the second reference value (Ps), the process proceeds to step 103. On the other hand, if the control unit 30 determines in step 102 that the pre-measurement value (P ₀ ) is smaller than the second reference value (Ps), the control unit 30 proceeds to step 104 to activate the motor 21 (FIG. 4) and perform the pre-measurement. After the value (P ₀ ) becomes larger than the second reference value (Ps), the process proceeds to step 103. That is, the process proceeds to step 103 after the tank internal pressure is set to be higher than the second reference value (Ps).

  In step 103, it is determined whether the motor 21 is operating, that is, whether the motor 21 is rotating. When the control unit 30 determines in step 103 that the motor 21 is not rotating, the process proceeds to step 105, and when it determines that the motor 21 is rotating, the process proceeds to step 201.

The control unit 30 that has proceeded to step 105 measures the tank internal pressure again to acquire a measured value. Specifically, the control unit 30 stores the tank internal pressure detected by the pressure sensor 35 in the RAM 32 as a first measured value (P ₁ ). Note that the first measurement value (P ₁ ) may be an average value of pressures measured a plurality of times near the measurement point.

On the other hand, the control unit 30 that has shifted to step 201 executes step 105 after executing steps 201 to 204 and stores the first measured value (P ₁ ) in the RAM 32. The control unit 30 that has proceeded to step 201 stops the motor 21 started in step 104. Subsequently, the control unit 30 causes the timer 34 to start counting (step 202). Next, the control unit 30 stops the timer 34 after the second predetermined time has elapsed, resets the count, and executes step 105. Specifically, the control unit 30 determines whether or not the count of the timer 34 has reached a predetermined value (T ₂ ) (step 203), and if the count has reached the predetermined value (T ₂ ), In step 204, the timer 34 is stopped, the count is reset, and step 105 is executed.

The control unit 30 having stored the first measured value (P ₁ ) in the RAM 32 in step 105 moves to step 106 and causes the timer 34 to start counting. Next, the control unit 30 stops the timer 34 after the first predetermined time has elapsed, resets the count, and proceeds to step 109. Specifically, the control unit 30 determines whether or not the count of the timer 34 has reached a predetermined value (T ₁ ) (step 107), and if the count has reached the predetermined value (T ₁ ), The process proceeds to step 108 to stop the timer 34, reset the count, and then proceeds to step 109.

The control unit 30 that has proceeded to step 109 measures the tank internal pressure again to obtain a measured value. Specifically, the control unit 30 stores the tank internal pressure detected by the pressure sensor 35 in the RAM 32 as a second measured value (P ₂ ). Note that the second measurement value (P ₂ ) may be an average value of the pressures measured a plurality of times near the measurement point.

In the following step 110, the difference between the first measurement value (P ₁ ) obtained in step 105 and the second measurement value (P ₂ ) obtained in step 109 is compared with a first reference value (Pj). Specifically, the control unit 30 calculates a difference value ΔP (P ₁ −P ₂ ) between the first measurement value (P ₁ ) and the second measurement value (P ₂ ) stored in the RAM 32, This is compared with a preset first reference value (Pj).

Thereafter, when the difference value ΔP (P ₁ −P ₂ ) is larger than the first reference value (Pj), the control unit 30 determines that “there is an air leak”, shifts to step 111, and proceeds to step 111. Then, the process is terminated after turning on the LED 28 provided in the. On the other hand, when the difference value ΔP (P ₁ −P ₂ ) is smaller than the first reference value (Pj), it is determined that “no air leakage”, and the process ends without turning on the LED 28. That is, the second reference value (Ps) is a threshold value for determining whether or not air leak detection is possible, whereas the first reference value (Pj) is a threshold value for determining presence or absence of air leakage.

As described above, when the air leak detection mode is selected, the first measurement value measured in advance and (P _1), the first measurement value (P ₁₎ a first predetermined time after measuring the (T ₁₎ The difference value ΔP (P ₁ −P ₂ ) from the second measurement value (P ₂ ) measured after the lapse of the period is compared with the first reference value (Pj), and based on the comparison result, the air leakage is performed. Is determined (FIG. 7). In other words, the presence or absence of air leakage is determined based on whether or not the amount of decrease in the tank internal pressure within a certain time is greater than a predetermined threshold. Further, instead of the difference value ΔP, a pressure change rate (gradient) between the first measured value (P ₁ ) and the second measured value (P ₂ ) is obtained, and the obtained pressure change rate (gradient) is calculated. Compared with a predetermined reference value for the pressure change rate, if the pressure change rate is large (in the case of a steep slope), it is determined that "air leaks", and if the pressure change rate is small (in the case of a gentle slope) ) May be determined as “no air leakage”.

Here, as shown in FIG. 6, prior to the measurement of the first measurement value (P ₁ ) (step 105), the presence or absence of rotation of the motor 21 is determined (step 103). If the motor 21 is not rotating, the first measurement value (P ₁ ) is measured as it is, while if the motor 21 is rotating, the first measurement value (P ₁ ) is executed after steps 201 to 204 are executed. (P ₁ ) is measured. The reason why the presence or absence of rotation of the motor 21 is determined before the measurement of the first measurement value (P ₁ ) and the control is made different depending on the determination result will be described.

If the control unit 30 determines in step 102 that the pre-measured value (P ₀ ) is smaller than the second reference value (Ps), the process proceeds to step 104 to start the motor 21 and increase the tank internal pressure. FIG. 8 shows a graph of the change in the tank internal pressure at this time. That is, when the motor 21 is started to fill the air tanks 10a and 10b (FIG. 1) with compressed air, the tank internal pressure temporarily shows a high value due to a temperature rise (compression heat). Thereafter, when the motor 21 is stopped, the temperature of the compressed air in the air tanks 10a and 10b decreases, and accordingly, the tank internal pressure also decreases. That is, in order to accurately measure the first measurement value (P ₁ ), it is necessary to wait for the change in the tank internal pressure due to the temperature change to settle. Therefore, in the control flow shown in FIG. 6, when the motor 21 is started in step 104 to increase the tank internal pressure, steps 201 to 204 are executed and then step 105 is executed. ing. In short, the first measurement value (P ₁ ) is measured after the second predetermined time (T ₂ ) has elapsed after stopping the motor 21 in step 201.

  FIG. 9 shows an example of a use state of the air compressor 1. In the illustrated use state, the air compressor 1 and the sub tank 40 are connected via an air hose 41, and the sub tank 40 and the pneumatic tool 50 are connected via an air hose 51. The illustrated pneumatic tool 50 is a nail driver that drives nails into wood or the like by the pressure of compressed air.

  The compressed air stored in the air tanks 10 a and 10 b of the air compressor 1 is sent to the sub tank 40 via the air hose 41 and stored in the sub tank 40. The compressed air stored in the sub tank 40 is supplied to the nailing machine 50 via the air hose 51.

  As shown in FIG. 9, when the air compressor 1, the sub-tank 40 and the nailing machine 50 are connected in series via the air hoses 41 and 51, the air compressor 1, the air hoses 41 and 51, the sub-tank 40 and the nailing machine 50 When air leakage occurs in any of the above cases, the internal pressure of the air tanks 10a and 10b of the air compressor 1 decreases.

  Therefore, if it is determined that “there is air leakage” as a result of executing the air leakage detection mode under the connection state shown in FIG. 9, any of the air compressor 1, the air hoses 41 and 51, the sub tank 40, and the nailing machine 50 It can be seen from FIG. Thereafter, the connection with the nailing machine 50 is released, and the air leak detection mode is executed again. As a result, if "no air leakage" is determined, it is determined that the source of the air leak is the nailing machine 50. Can be identified. On the other hand, if it is determined that “there is an air leak”, the source of the air leak is not the nailer 50 but the sub-tank 40, the air hoses 41 and 51 or the air compressor 1 located upstream of the nailer 50. Can be specified. As described above, if the air leak detection mode is executed a plurality of times while sequentially removing the sub-tank 40, the air hoses 41 and 51, and the nailing machine 50 connected to the air compressor 1, the source of the air leak is finally determined. Can be identified.

  As described above, according to the air compressor 1 according to the present embodiment, not only the air leak in the air compressor itself, but also the air leak in the sub tank 40, the air hoses 41 and 51, and the nailing machine 50 connected to the air compressor 1. Can also be detected.

The present invention is not limited to the above embodiment, but can be variously modified without departing from the gist thereof. For example, at least one of the first reference value (Pj), the second reference value (Ps), the first predetermined time (T ₁ ), and the second predetermined time (T ₂ ) can be changed. In this case, each value can be changed to an arbitrary value by operating the input unit on the operation panel 19.

  Steps 201 to 204 shown in FIG. 6 may be omitted when the change in the tank internal pressure due to the change in the temperature of the compressed air is negligible or allowable.

  In the above embodiment, the control unit 30 that has determined that there is an air leak reports the determination result by light. Specifically, the control unit 30 illuminates the LED 28 provided on the operation panel 19 to notify the determination result. However, the determination result may be notified by blinking the LED 28 or turning off the LED 28 that has been lit up to that time. In addition, the determination result may be notified by sound in addition to or instead of light. For example, a speaker may be provided in addition to or in place of the LED 28, and the speaker may emit a notification sound or a message to notify the determination result.

  Further, the control unit 30 notifies the determination result and operates an opening / closing means such as an electromagnetic valve (not shown) to automatically stop the supply of the compressed air from the air tanks 10a and 10b to the air hose 41 and the air tool 50. Embodiments are also included in the present invention.

  Although the air compressor 1 according to the above embodiment is a multi-stage air compressor having two sets of cylinders and pistons, the number of cylinders and pistons may be one or three or more. Further, the air compressor to which the present invention is applied is not limited to a reciprocating air compressor, but may be applied to, for example, a rotary air compressor.

1 Air compressors 10a, 10b Air tank 19 Operation panel 20 Compressed air generator 21 Motor 21a Stator 21b Rotor 21c Motor rotation shaft (crank shaft)
22 Crank case 23A First cylinder 23B Second cylinder 23a First piston 23b Second piston 26 Mode switch 27 Display 28 LED
30 control unit 32 RAM
33 ROM
34 Timer 35 Pressure sensor 40 Sub tank 41, 51 Air hose 50 Pneumatic tool (Nailer)

Claims (10)

A compressed air generation unit, an air tank that stores compressed air generated by the compressed air generation unit, a pressure sensor that detects an internal pressure of the air tank, and a control unit that controls the compressed air generation unit. An air compressor,
A normal operation mode in which the compressed air generator is controlled so that the internal pressure of the air tank is maintained within a predetermined range; and an air leak detection mode in which air leakage is detected based on a change in the internal pressure of the air tank. And, an arbitrary operation mode can be selected from a plurality of operation modes including
The control unit, when the air leak detection mode is selected,
Measure the internal pressure of the air tank to obtain a pre-measured value, and when the obtained pre-measured value is larger than a predetermined reference value , measure the internal pressure of the air tank to obtain a first measured value. When the acquired and obtained pre-measured value is smaller than the reference value, the internal pressure of the air tank is made higher than the reference value by the operation of the compressed air generation unit, and the compressed air generation is performed. Measuring the internal pressure of the air tank after the second predetermined time has elapsed since the stop of the unit to obtain the first measurement value,
After a first predetermined time has elapsed since the acquisition of the first measurement value, the internal pressure of the air tank is measured again to acquire a second measurement value,
Comparing a difference value between the first measurement value and the second measurement value with a first reference value,
If the difference value is larger than the first reference value, it is determined that there is an air leak, and if the difference value is smaller than the first reference value, it is determined that there is no air leak,
air compressor. The air compressor according to claim 1, wherein the control unit that determines that there is an air leak reports the determination result by at least one of sound and light. Having an LED controlled by the control unit,
The control unit determines that there is an air leak, turns on or blinks the LED, and notifies the determination result,
The air compressor according to claim 2 . Having a speaker controlled by the control unit,
The control unit that has determined that there is an air leak notifies the determination result by causing the speaker to emit a notification sound,
The air compressor according to claim 2 . The air compressor according to any one of claims 1 to 4 , wherein at least one of the reference value , the first reference value , and the first predetermined time is changeable. The air compressor according to claim 1 , wherein the second predetermined time can be changed.   The air compressor according to claim 1, wherein the motor that is a power source of the compressed air generation unit is not operated until the first predetermined time has elapsed. The air compressor according to claim 2 , wherein the control unit controls the electromagnetic valve so as to prevent the compressed air from leaking from the air tank after notifying the determination result.   The air compressor according to claim 1, wherein the first measurement value and the second measurement value are average values of pressures measured a plurality of times. A compressed air generation unit, an air tank that stores compressed air generated by the compressed air generation unit, a pressure sensor that detects an internal pressure of the air tank, and a control unit that controls the compressed air generation unit. An air compressor,
A normal operation mode in which the compressed air generator is controlled so that the internal pressure of the air tank is maintained within a predetermined range, and an air leak detection mode in which air leakage is detected based on a change in the internal pressure of the air tank. And, an arbitrary operation mode can be selected from a plurality of operation modes including
The control unit, when the air leak detection mode is selected,
Measuring the internal pressure of the air tank to obtain a pre-measured value, and when the obtained pre-measured value is larger than a first reference value , measuring the internal pressure of the air tank to obtain a first measured value When the acquired pre-measured value is smaller than the first reference value, the internal pressure of the air tank is higher than the first reference value by the operation of the compressed air generation unit. And, after a second predetermined time has elapsed since the compressed air generation unit stopped, measuring the internal pressure of the air tank to obtain the first measurement value,
After a first predetermined time has elapsed since the acquisition of the first measurement value, the internal pressure of the air tank is measured again to acquire a second measurement value,
Comparing the rate of pressure change between the first measured value and the second measured value with a predetermined second reference value;
If the pressure change rate is larger than the second reference value, it is determined that there is air leakage, and if the pressure change rate is smaller than the second reference value, it is determined that there is no air leak,
air compressor.

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