JP6471703B2 - Airtight leak inspection device and airtight leak inspection method - Google Patents

Description

  The present invention relates to an airtight leak inspection apparatus and an airtight leak inspection method.

  2. Description of the Related Art Conventionally, there are known airtight leak inspection apparatuses for inspecting airtight leakage of workpieces using automobile parts such as common rails and injector pumps as inspection objects (hereinafter referred to as “workpieces”). For example, in the inspection apparatus described in Patent Document 1, a difference between a pressure-proof master work and a work for inspection, which are both airtight and pressurized, is detected simultaneously to detect a differential pressure, and the air-tight leak of the work is determined to pass or fail. The pressure leak method is adopted.

  However, this inspection apparatus has a complicated structure including a differential pressure sensor and a plurality of solenoid valves, and it has been difficult to achieve a simple and inexpensive structure. In general, the differential pressure leak method is limited to air leak measurement. For example, a medium such as dimethyl ether (hereinafter, “DME”) cannot perform a leak test.

Japanese Patent No. 4112340

  On the other hand, an inspection apparatus is also known in which a work is immersed in a water tank and gas leaking from the work is collected by a water displacement method. However, the water displacement method can measure with high accuracy for a medium with low solubility in water such as air, but if the target medium has high solubility, the medium will dissolve in water. Therefore, there is a problem that the medium cannot be collected with high accuracy.

  The present invention was created in view of the above points, and an object thereof is to provide an airtight leak inspection apparatus and an airtight leak inspection method capable of performing a highly accurate airtight leak inspection with a simple configuration. There is to do.

  The airtight leakage inspection apparatus of the present invention is an airtight leakage inspection apparatus that inspects the airtightness of an inspection object (W) having a fluid storage chamber (51). The airtight leakage inspection apparatus includes a pressurizing unit (10), a liquid container (23), a volume variable member (18), a measuring container (25), a measuring unit (26, 27), and a control unit (40). And comprising.

  The pressurizing unit supplies a fluid to the fluid storage chamber or the chamber (15) that stores the inspection object, and applies a predetermined test pressure (Pt). The liquid container is filled with liquid and has a constant volume. The variable volume member is immersed in the liquid container, communicates with the fluid storage chamber or chamber, and changes its external shape following changes in the internal pressure. The measurement container communicates with the liquid container via the connection pipe (24) filled with the liquid. The measurement unit measures a liquid change amount (ΔM) in the measurement container that changes corresponding to a volume change of the volume variable member in the liquid container. The control unit calculates a leakage amount (ΔQ) of the inspection object based on the measurement value (M1) by the measurement unit.

According to the configuration of the present invention, by measuring the volume change of the volume variable member immersed in the liquid container as the liquid change amount in the measurement container, the leakage of the inspection object based on the measured value is measured. The amount can be measured. Even if the medium leaking from the fluid storage chamber of the inspection object or the medium entering the fluid storage chamber due to lack of airtightness is a water-soluble substance, the medium itself directly touches the liquid in the liquid container, for example, water. Therefore, a highly accurate airtight leak inspection can be performed.
Furthermore, since it is not necessary to have a differential pressure sensor or a plurality of solenoid valves, a simple configuration can be achieved.

The cross-sectional schematic diagram explaining schematic structure of the airtight leak test | inspection apparatus by 1st Embodiment of this invention. The flowchart which shows an example of the water injection control which a control apparatus performs. The flowchart which shows an example of leak measurement control. The timing chart which shows an example of leak measurement control. The cross-sectional schematic diagram explaining schematic structure of the airtight leak test | inspection apparatus by 2nd Embodiment of this invention. The flowchart which shows an example of correction amount calculation control. The timing chart which shows an example of correction amount calculation control. The figure which shows correction | amendment control on a graph. The cross-sectional schematic diagram explaining the schematic structure of the airtight leak test | inspection apparatus by 3rd Embodiment of this invention. Sectional schematic diagram explaining schematic structure of the airtight leak test apparatus by 5th Embodiment of this invention. The flowchart which shows an example of leak measurement control. The timing chart which shows an example of leak measurement control. The cross-sectional schematic diagram explaining schematic structure of the airtight leak test apparatus by 6th Embodiment of this invention. The flowchart which shows an example of leak measurement control. The cross-sectional schematic diagram explaining schematic structure of the airtight leak inspection apparatus by 7th Embodiment of this invention. The flowchart which shows an example of leak measurement control.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
[Constitution]
An airtight leakage inspection apparatus 101 according to a first embodiment of the present invention will be described with reference to FIGS. First, the configuration will be described with reference to FIG. As shown in FIG. 1, the airtight leakage inspection apparatus 101 of the present embodiment includes a regulator 11, a first pipe 12, a first valve 13, a first pressure sensor 14, a chamber 15, a second pipe 16, a second valve 17, Pack 18, third pipe 19, third valve 21, cylinder 22, water tank 23, connection pipe 24, female cylinder 25, electronic balance 26, camera 27, fourth pipe 28, fourth valve 29, fifth pipe 31, A fifth valve 32 and a control unit 40 are provided.

  The first pipe 12 connects a supply tank (not shown), which is a fluid supply source, and the work 50. In this embodiment, DME is used as a medium (fluid) to be enclosed. The medium is compressed at high pressure and is liquid when enclosed. The regulator 11, the first valve 13, and the first pressure sensor 14 are provided in the middle of the flow path of the first pipe 12, and constitute a pressurizing unit 10 that supplies a predetermined test pressure Pt to the workpiece 50 as an inspection object. . The first valve 13 can open and close the flow path in the first pipe 12.

  In FIG. 1, a portion indicated by a dot is a portion to which a predetermined test pressure Pt is applied by the pressurizing unit 10. The same applies to FIGS. 5, 9, 10, 13, and 15 in the following embodiments.

  A workpiece 50 is accommodated in the chamber 15. The workpiece 50 is an automobile part such as a common rail used for a diesel engine or an injector pump. A fluid storage chamber 51 is formed in the work 50.

  The chamber 15 is provided with an opening / closing door (not shown) so that an operator can open the opening / closing door and attach the workpiece 50 therein. A space surrounded by the inner wall of the chamber 15 and the outer wall of the work 50 is formed as a flow path 54 of the medium leaking from the work 50 as indicated by an arrow A1.

  The second pipe 16 connects the chamber 15 and the pack 18. The lower end of the second pipe 16 is formed to extend into the water storage tank 23. The second valve 17 is provided in the middle of the flow path of the second pipe 16 and can open and close the flow path in the second pipe 16. In the present embodiment, when the medium is sealed in the work 50 at a predetermined test pressure Pt, the medium leaked from the work 50 flows into the pack 18 via the flow path 54 and the second pipe 16. To do.

  The third pipe 19 is formed by branching from the middle of the second pipe downstream from the second valve 17, and the cylinder 22 is connected to the downstream side. The third valve 21 is provided in the middle of the flow path of the third pipe 19, and can open and close the flow path in the third pipe 19. The cylinder 22 is a device for sucking the volume of the pack 18 increased during the inspection. The cylinder 22 corresponds to an example of a “suction part” described in the claims.

  The water tank 23 is provided on the base 41. The water storage tank 23 corresponds to an example of a “liquid container” described in the claims. A water storage portion 42 having a constant volume is formed inside the water storage tank 23, and the water storage portion 42 is filled with water W. The upper base 43 of the water storage portion 42 is formed in a gently tapered shape so as to protrude upward, and when water is poured from below, bubbles in the water storage portion 42 are efficiently discharged to the outside. The air pocket is removed.

  The fourth pipe 28 connects a water supply source (not shown) and the water storage unit 42. The fourth pipe 28 is connected to a portion near the lower bottom in the water accommodating portion 42, and a fourth valve 29 is provided in the middle of the flow path. The fourth valve 29 can open and close the flow path in the fourth pipe 28. Although water injection will be described in detail later, water is supplied from the fourth pipe 28 to the water accommodating portion 42. The fifth pipe 31 extends from the upper bottom 43 to the upper part of the water accommodating portion 42, and a fifth valve 32 is provided in the middle of the flow path. The fifth valve 32 can open and close the flow path in the fifth pipe 31.

  The connection pipe 24 connects the water storage part 42 and the graduated cylinder 25. The connection pipe 24 has a first part 34, a second part 35, and a third part 36. The first portion 34 is formed so that the lower end thereof is immersed near the lower bottom of the water accommodating portion 42 and extends upward through the upper bottom 43 of the water accommodating portion 42. The second portion 35 is formed to extend in the horizontal direction continuously to the first portion 34. The third portion 36 is formed to extend downward in the vertical direction continuously to the second portion 35, and its lower end is located in the graduated cylinder 25. At the time of inspection, the connection pipe 24 is also filled with water W, and the water W is stored in the graduated cylinder 25 to the extent that the lower end of the third portion 36 comes into contact with the liquid.

  At the time of inspection, the medium leaking from the work 50 is vaporized when the pressure drops, and leaks into the flow path 54 as a gas. When the volume of the pack 18 is increased by the medium leaking from the workpiece 50, the increased volume of water W overflows from the water accommodating portion 42 and flows into the graduated cylinder 25 via the connection pipe 24. Therefore, the mass or volume of water in the graduated cylinder 25 before the start of inspection, that is, before the medium leaks, and the mass or volume of water in the graduated cylinder 25 after a certain time has elapsed since the start of the inspection are measured. Thus, the leakage amount of the medium leaking from the workpiece 50 can be obtained. Details of the measurement method will be described later.

  The electronic balance 26 measures the weight of water in the graduated cylinder 25 and is provided on the base 41. A camera 27 for reading the volume scale is provided on the side of the measuring cylinder 25. A windshield case 45 is disposed around the graduated cylinder 25 for precise measurement. The electronic balance 26 and the camera 27 correspond to an example of a “measurement unit” recited in the claims. The measuring cylinder 25 corresponds to an example of a “measurement container” described in the claims.

  The pack 18 is immersed in the water storage portion 42 of the water storage tank 23 and is connected to the lower end of the second pipe 16. The pack 18 is, for example, a thin bag-shaped pack for collecting gas, and is formed of a material that is hardly soluble in water and DME, and the volume thereof can be changed by a change in internal pressure. The pack 18 corresponds to an example of a “volume variable member” described in the claims.

  The control unit 40 includes a microcomputer including a CPU, a ROM, a RAM, an input / output port, and the like, and includes a first pressure sensor 14, valves 13, 17, 21, 29, 32, a cylinder 22, an electronic balance 26, and The camera 27 is electrically connected. The control unit 40 executes various programs and controls opening / closing driving of the valves 13, 17, 21, 29, 32 and driving of the cylinder 22 based on detection signals from the first pressure sensor 14 and the like. Further, the control unit 40 is based on detection data detected by the electronic balance 26 or the camera 27. Various arithmetic processes are executed.

[Water injection method]
Next, the measurement method by the airtight leakage inspection apparatus 101 having the above configuration will be described in order from the water injection method to the water storage tank 23. As shown in FIG. 2, first, in step 1 (hereinafter, “step” is abbreviated as S), the fourth valve 29 is opened. Next, in S2, the fifth valve 32 is opened. That is, water is injected from the fourth valve 29 with both the fourth valve 29 and the fourth valve 29 opened.

Next, in S3, it is determined whether or not a predetermined set time Δt ₅ has elapsed. If the set time Δt ₅ has elapsed, the fifth valve 32 is closed in S4. It should be noted that the time elapse step is illustrated in a simplified manner. Actually, when the set time Δt ₅ has not elapsed and a negative determination is made, the set time Δt ₅ has elapsed and the result is positive. The determination step is repeatedly executed until the determination is made. In the following specification, the same description is given regarding the elapsed step by the preset time control.

The set time Δt ₅ is set to a time from when the fourth valve 29 is opened to start water injection until water overflows from the fifth valve 32. That is, the fifth valve 32 is closed at the timing when water overflows from the fifth valve 32. Next, in S5, it is determined whether or not a predetermined set time Δt ₄ has elapsed. If the set time Δt ₄ has elapsed, the fourth valve 29 is closed in S6. The set time Δt ₄ is set to a time when water is filled from the connection pipe 24 to the measuring cylinder 25. That is, the fourth valve 29 is closed at the timing when the connection pipe 24 is filled with water. By the above water injection control, water gradually accumulates upward from the bottom of the water accommodating portion 42, and the water is filled up to the water accommodating portion 42, the connection pipe 24, and the fifth valve 32 of the fifth pipe 31. The

[Leakage measurement control]
Next, the leak measurement control and the leak measurement method will be described. This leakage measurement control is executed after the water injection control is completed and the water storage tank 23 is filled with water. FIG. 3 is a flowchart showing an example of leakage measurement control, and corresponds to the timing chart shown in FIG. As shown in FIG. 3, first, in S <b> 11, the work 50 is installed in the chamber 15 by the operator.

  Next, in S12, the control unit 40 opens the first valve. In addition, the process from S12 to S24 is executed by the control unit 40. In S13, the pressure (hereinafter referred to as “work pressure”) Pw in the workpiece 50 is measured by the first pressure sensor 14, and in S14, it is determined whether or not the measured workpiece pressure Pw has reached a predetermined test pressure Pt. Is done. If the determination in S14 is affirmative, the process proceeds to S15. On the other hand, if the determination in S14 is negative, the determination in S14 is repeated. The processing of S12 to S14 corresponds to an example of a “pressurization stage” described in the claims.

After the workpiece pressure Pw reaches the predetermined test pressure Pt, the second valve 17 is opened in S15 and measurement is started. Next, in S16, the mass M ₀ of the electronic balance 26 at the start of measurement is measured. In S17, it is determined whether or not a preset inspection time Δt has elapsed. If the inspection time Δt has elapsed, the process proceeds to S18, and the mass M ₁ of the electronic balance 26 is measured.

The inspection time Δt is appropriately set according to the required inspection accuracy, and is set to about 10 to 20 minutes, for example. Further, the measured mass M ₁ corresponds to an example of “measured value” described in the claims. Next, in S19, the leakage amount ΔQ is calculated from the mass difference ΔM = M ₁ −M ₀ between the start time and the end time. Here, assuming that the density of water at the reference temperature T ₀ is ρ ₀ , the leakage amount ΔQ is expressed by Expression (1). The process of S19 corresponds to an example of a “leak amount calculation stage” described in the claims. Further, the mass difference ΔM corresponds to an example of “amount of change in liquid” recited in the claims.

After ΔQ is calculated by the equation (1), the second valve 17 is closed in S20, and the medium inflow to the pack 18 due to the work leakage is stopped. Next, in S21, the third valve 21 is opened, and in S22, the cylinder 22 is moved for a predetermined time. This step is a process of sucking the medium enclosed in the pack 18 and returning it to the original volume of the pack 18 because the volume of the pack 18 is increased by the inflow of the medium. The time Δt ₃ for returning the volume of the pack 18 to the original state is expressed by Expression (2), where u is the moving speed of the cylinder 22 and A is the cross-sectional area of the cylinder 22.

After the cylinder 22 is moved by time Δt ₃ , the third valve 21 is closed in S23. Next, in S24, the first valve is closed. Further, in S25, the work 50 is removed from the chamber 15 by the operator, and this control process is ended.

In the flowchart shown in FIG. 3, the mass value obtained by the electronic balance 26 is used for leakage amount conversion, but the leakage amount can also be calculated by reading the volume scale by the camera. In this case, the volume L ₀ of the measuring cylinder 25 is read by the camera in S16, and the volume L ₁ of the measuring cylinder 25 is read by the camera in S18. The leakage amount ΔQ = ΔL / Δt can be calculated from the volume difference ΔL = L ₁ −L ₀ between the start time and the end time.

[effect]
As described above, in the first embodiment, the medium leaked from the work 50 is once collected in the pack 18 and the volume change of the pack 18 is converted into the mass change or volume change of the water in the water storage tank 23. Thus, the leak amount ΔQ of the workpiece 50 is calculated. Since the medium does not directly contact water, even a water-soluble medium that dissolves in water can be measured with high accuracy.

  Further, it is not necessary to provide a differential pressure sensor and a plurality of electromagnetic valves as compared with the conventional differential pressure leak method, and a simple and inexpensive apparatus configuration can be obtained.

  Furthermore, since the lower end of the third portion 36 of the connection pipe 24 is in contact with the liquid in the measuring cylinder, the pack 18 is not in contact with liquid and is dropped from the connection pipe 24. A change in the amount of water corresponding to the increase in volume can be suitably grasped in the measuring cylinder 25. Specifically, in the case of the dropping form, it takes time to drop due to the influence of the surface tension at the lower end of the connecting pipe 24, and this makes it difficult to grasp a slight increase. This is because it is difficult to be affected by the liquid contact as in the embodiment.

  In the inspection of this embodiment, the leaked medium flows in the chamber, so that the medium does not leak outside the apparatus 101.

Second Embodiment
[Constitution]
Next, an airtight leak inspection apparatus 102 according to a second embodiment of the present invention will be described with reference to FIGS. First, the configuration will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the structure similar to 1st Embodiment, and description is abbreviate | omitted. The hermetic leak inspection apparatus 102 of the second embodiment further includes a sixth pipe 61, a second pressure sensor 62, a sixth valve 63, and a measurement master 64 as compared to the hermetic leak inspection apparatus 101 of the first embodiment. Is different.

  The sixth pipe 61 is branched from the downstream position of the first valve 13 in the middle of the flow path of the first pipe 12, and is formed to the upstream position of the third valve 21 in the middle of the flow path of the third pipe 19. Yes. In the middle of the flow path of the sixth pipe 61, a second pressure sensor 62, a measurement master 64, and a sixth valve 63 are provided in order from the upstream. The measurement master 64 generates a known flow rate at a specified pressure, and includes an orifice or a nozzle.

[Correction amount Δq calculation control by measurement master 64]
Next, correction amount Δq calculation control by the measurement master 64 will be described. This control is a control that is periodically executed once a day, for example, as a stage before measuring the leakage of the workpiece 50. Based on the correction amount Δq calculated by this control, the leakage amount calculated for the workpiece 50 is corrected. In addition, in calculating the correction amount Δq, it is the same as the first embodiment in that the water injection control is finished and the water tank 23 is filled with water.

  FIG. 6 is a flowchart showing an example of the correction amount Δq calculation control, and corresponds to the timing chart shown in FIG. This control is substantially the same as the leak measurement control described in the first embodiment, except that the workpiece master 50 is not pressurized but the measurement master 64 is pressurized. First, in S11-2, the measurement master 64 is attached by an operator, and the first valve is opened by the control unit 40 in S12.

  In S13-2, the pressure in the measurement master 64 (hereinafter referred to as “master pressure”) Pm is measured by the second pressure sensor 62, and in S14-2, the measured master pressure Pm has reached a predetermined test pressure Pt. It is determined whether or not. If the determination in S14-2 is affirmed, the process proceeds to S15-2. On the other hand, if the determination in S14-2 is negative, the determination in S14 is repeated.

After the master pressure Pm reaches the predetermined test pressure Pt, the sixth valve is opened in S15-2 and measurement is started. Hereinafter, mass measurement in S16 to S18 is the same as in the first embodiment. In S19-2, a correction amount Δq is calculated. The measurement master 64 can correct the measurement value from the measurement value and the known master value. The master leakage amount ΔQ _m is a known value, and the true mass ΔM _m to be detected is expressed by Equation (3), where the measurement time is Δt and the water density at the reference temperature is ρ ₀ .

The mass ΔM _m represented by the formula (3) is a true mass, and corresponds to an example of a “true amount” described in the claims. On the other hand, if the mass change actually measured by the electronic balance 26 is ΔM, the difference from the true mass is ΔM _m −ΔM, which is an amount to be corrected. Therefore, the leakage correction amount Δq is expressed by the equation (4).

Therefore, the corrected leak amount ΔQ _hosei indicated by a broken line in FIG. 8 is expressed by Equation (5), _{where the} measured value by the workpiece 50 is ΔQ _n .

In the case of volume detection, if the volume change actually measured in the graduated cylinder 25 is ΔL, the difference from the true volume is ΔQ _m × Δt−ΔL, which is an amount to be corrected. Therefore, the leakage correction amount Δq is expressed by the equation (6).

  The process of S19-2 corresponds to an example of a “correction amount calculation stage” described in the claims. After calculating the correction amount Δq, the sixth valve is closed in S20-2. Thereafter, in S21 to S24, the cylinder 22 is driven to release the pressure and stop the medium encapsulation. This process is the same as in the first embodiment. Finally, in S25-2, the measurement master 64 is removed by the operator, and this control process ends.

In the second embodiment, the leakage measurement control of the workpiece 50 is the same as that of the first embodiment shown in FIG. 3, and in the calculation of the leakage amount ΔQ in S19, the measured value ΔQ _n of the workpiece 50 is _expressed by the above equation (5). In addition, the amount of correction Δq is taken into account and the amount of leakage ΔQ _hosei is calculated.

According to the second embodiment, the same effects as those of the first embodiment can be obtained, and more accurate leakage measurement can be performed by correcting the measured value ΔQ _n with the correction amount Δq. Further, by periodically measuring the correction amount Δq by the measurement master 64, it can be used for daily accuracy management of the inspection apparatus 102, so that the reliability of the inspection apparatus 102 can be improved.

  Furthermore, if the value of the correction amount Δq is large, it can be recognized that the inspection apparatus is defective, and therefore the correctness of the inspection apparatus 102 can be verified. In addition, if the correction amount Δq is constant, the correctness of the apparatus 102 is guaranteed in the long term.

<Third Embodiment>
[Constitution]
Next, an airtight leakage inspection apparatus 103 according to a third embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the structure similar to 1st Embodiment, and description is abbreviate | omitted. The airtight leak inspection apparatus 103 according to the third embodiment is different from the airtight leak inspection apparatus 101 according to the first embodiment in that it further includes a temperature sensor 65 that detects the water temperature of the water storage tank 23. The temperature sensor 65 is connected to the control unit 40. The temperature sensor 65 corresponds to an example of “temperature detection means” recited in the claims.

[Correction control by temperature change]
If there is a change in water temperature during detection, a measurement error occurs due to the volume expansion or contraction of water. In 3rd Embodiment, the water temperature in the water storage tank 23 is detected, and temperature correction is performed. Hereinafter, the correction method of the water temperature change in the water storage tank 23 will be described. It is assumed that the mass detected by the electronic balance 26 is ΔM = M ₁ −M ₀ and the change in water temperature is ΔT = T ₁ −T ₀ . Here, T ₀ is the water temperature at the start of measurement, and T ₁ is the water temperature at the end of measurement. Furthermore, if the sum of the volume of the water storage tank 23 and the piping volume from the water storage tank 23 to the graduated cylinder 25 is V, and the volume expansion rate of water is β, the leak amount ΔQ _temp after temperature correction is expressed by equation (7). Is done. Here, Δt is the measurement time, and ρ ₀ is the water density at the reference temperature.

Similarly, assuming that the volume detected by the graduated cylinder 25 is ΔL = L ₁ −L ₀ , the leak amount ΔQ _temp after temperature correction is expressed by Expression (8).

  According to the third embodiment, it is possible to perform leak measurement with higher accuracy by correcting the error due to the change in the water temperature of the water storage tank 23 while achieving the same effect as the first embodiment.

<Fourth embodiment>
Next, an airtight leakage inspection apparatus according to a fourth embodiment of the present invention will be described. The fourth embodiment is characterized in that an error due to water pressure in the water storage tank 23 is corrected, and the device configuration itself may be any device configuration from the first embodiment to the third embodiment. . An example will be described with reference to the third embodiment shown in FIG.

In the present embodiment, the amount of leakage is calculated based on the volume change of the pack 18 in the water storage tank 23. Therefore, the volume leaked in the atmospheric pressure P ₀ changes depending on the position of the pack 18 in the water storage tank 23. Let ΔQ _{0 be} the leakage that has leaked in the atmosphere, Δt the measurement time, and ΔL ₀ = ΔQ ₀ × Δt the volume. Since the volume ΔL ₀ leaked in the atmosphere contracts due to water pressure, the volume increment of the pack 18 decreases and an error occurs. Here, when the average height from the upper surface of the water storage section 42 of the water storage tank 23 to the pack 18 is h, the water density at the reference temperature is ρ ₀ , and the measured volume difference is ΔL, these are the relations of the equation (9). It is expressed by a formula.

Therefore, the original leakage amount ΔQ ₀ is expressed by Expression (10).

Further, from ΔL = ΔM / ρ ₀ , the leakage amount ΔQ ₀ from the mass difference ΔM is expressed by Expression (11).

  According to the fourth embodiment, it is possible to perform leak measurement with higher accuracy by correcting the error due to the water pressure at the position of the pack 18 while achieving the same effect as the first embodiment.

<Fifth Embodiment>
[Constitution]
Next, an airtight leakage inspection apparatus 105 according to a fifth embodiment of the present invention will be described with reference to FIGS. First, the configuration will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the structure similar to 1st Embodiment, and description is abbreviate | omitted. The airtight leak inspection apparatus 105 according to the fifth embodiment is different from the airtight leak inspection apparatus 101 according to the first embodiment in that the chamber 15, the second valve 17, and the cylinder 22 are not included.

[Leakage measurement control]
Next, the leak measurement control and the leak measurement method will be described. In the fifth embodiment, a test pressure Pt is applied to the workpiece 50 and the pack 18 as indicated by dots in FIG. Then, as shown by arrow A5, when there is a leak in the work 50, the volume of the portion where the test pressure Pt is applied decreases, and the amount of leakage is measured by utilizing the decrease in the volume of the pack 18. When the volume of the pack 18 decreases, the water in the graduated cylinder 25 is sucked into the water storage tank 23 and the measured value decreases. This decrease amount is detected, and the leakage amount is calculated. In the present embodiment, since the water in the graduated cylinder 25 is sucked into the water storage tank 23 side, the piping in the graduated cylinder 25 and the water in the graduated cylinder 25 need to be in contact with each other.

  FIG. 11 is a flowchart showing an example of leakage measurement control, and corresponds to the timing chart shown in FIG. As shown in FIG. 11, first, in S <b> 51, the work 50 is attached between the first pipe 12 and the second pipe 16 by the operator. Next, in S52, the first valve is opened by the control unit 40. In S53, the work pressure Pw is measured by the first pressure sensor 14, and in S54, it is determined whether or not the measured work pressure Pw has reached a predetermined test pressure Pt. If the determination in S54 is affirmative, the process proceeds to S55. On the other hand, if the determination in S54 is negative, the determination in S54 is repeated.

After the workpiece pressure Pw reaches the predetermined test pressure Pt, the first valve 13 is opened and measurement is started in S55. Next, in S56, the mass M ₀ of the electronic balance 26 at the start of measurement is measured. In addition, since the process of S56-S59 is the same as that of S16-S19 shown in FIG. 3 in 1st Embodiment, description is abbreviate | omitted. Next, in S60, the third valve 21 is opened.

Next, in S63, the work pressure Pw is measured by the first pressure sensor 14, in S62, the measured workpiece pressure Pw whether decreased to atmospheric pressure P ₀ is determined. If the determination in S62 is affirmative, the process proceeds to S63. On the other hand, if the determination in S62 is negative, the process returns to S61 and the determination in S62 is repeated. If the work pressure Pw has decreased to the atmospheric pressure P ₀ , the third valve 21 is closed in S63. Next, in S64, the work 50 is removed by the operator, and this control process ends.

  Also in the fifth embodiment, since the medium does not come into direct contact with water, highly accurate leakage measurement is possible even with a water-soluble medium that dissolves in water. Further, since the chamber 15 and the cylinder 22 are not provided, the apparatus configuration can be further simplified.

<Sixth Embodiment>
Next, an airtight leakage inspection apparatus 106 according to a sixth embodiment of the present invention will be described with reference to FIGS. First, the configuration will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the structure similar to 1st Embodiment, and description is abbreviate | omitted. The airtight leak inspection apparatus 106 according to the sixth embodiment is substantially the same as the airtight leak inspection apparatus 101 according to the first embodiment, but includes the first pipe 12, the inner wall of the chamber 15, and the outer wall of the work 50 when the work is attached. The difference is that the enclosed flow path 54 communicates.

  In the embodiments so far, the amount leaked from the workpiece 50 is detected, but in the sixth embodiment, the amount of leakage in the direction of entering the workpiece 50 is detected as indicated by an arrow A6 in FIG. As shown by dots in FIG. 13, a test pressure Pt is applied to the chamber 15 to detect the amount of leakage that enters the work 50 from the flow path.

  FIG. 14 is a flowchart showing an example of leakage measurement control, and corresponds to the timing chart shown in FIG. The leak measurement control of the sixth embodiment is different from the leak measurement control of the first embodiment in that the object to which the test pressure Pt is applied is not the workpiece 50 but the chamber 15, but other leak amount calculation methods The same applies to.

In the present embodiment, as shown in FIG. 14, the pressure (hereinafter referred to as “chamber pressure”) Pc in the chamber 15 is measured in S13-6. Next, in S14-6, it is determined whether or not the measured chamber pressure Pc has reached a predetermined test pressure Pt. If the determination in S14-6 is affirmative, the process proceeds to S15. On the other hand, if the determination in S14-6 is negative, the process returns to S13-6, and the determination in S14-6 is repeated until the chamber pressure Pc reaches a predetermined test pressure Pt. Since other processes are the same as those in the first embodiment, description thereof will be omitted.
Also in the sixth embodiment, the same effects as in the first embodiment can be obtained.

<Seventh embodiment>
[Constitution]
Next, an airtight leak inspection apparatus 107 according to a seventh embodiment of the present invention will be described with reference to FIGS. 15 and 16. First, the configuration will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the structure similar to 6th Embodiment, and description is abbreviate | omitted. In the airtight leakage inspection apparatus 107 according to the seventh embodiment, the first pipe 12 and the chamber 15, and the chamber 15 and the second pipe 16 communicate with each other.

  Further, in the present embodiment, since the volume of the pack 18 is reduced, the cylinder 22 that sucks the increased volume of the pack 18 is not provided. The seventh embodiment is different from the sixth embodiment in that the test pressure Pt is applied in the chamber 15 and the pack 18 as indicated by dots in FIG.

  In the present embodiment, the test pressure Pt is applied to the chamber 15 and the pack 18, and the volume of the pack 18 is reduced by the medium being sucked into the work 50 due to the leakage of the work 50 as indicated by an arrow A7. The amount of leakage is calculated using this.

[Leakage measurement control]
FIG. 16 is a flowchart showing an example of leakage measurement control, and corresponds to the timing chart shown in FIG. The leak measurement control is substantially the same as the control of the fifth embodiment shown in FIG. In the present embodiment, when the first valve 13 is opened in S52, the chamber pressure Pc is measured in S53-7.

  Next, in S54-7, it is determined whether or not the measured chamber pressure Pc has reached a predetermined test pressure Pt. If the determination in S54-7 is affirmed, the process proceeds to S55. On the other hand, if the determination in S54-7 is negative, the process returns to S53-7, and the determination in S54-7 is repeated until the chamber pressure Pc reaches a predetermined test pressure Pt.

In addition, since the process of S55-S60 is the same as the process of the same step shown in FIG. 11 in 5th Embodiment, description is abbreviate | omitted. Then, in S61-7, the first pressure sensor 14 is measured chamber pressure Pc, the S62-7, the measured chamber pressure Pc whether decreased to atmospheric pressure P ₀ is determined. If the determination in S62-7 is affirmed, the process proceeds to S63. On the other hand, when the determination of S62-7 is negative, the process returns to S61-7 and the determination of S62-7 is repeated. When the chamber pressure Pc decreases to the atmospheric pressure P ₀ , the third valve 21 is closed in S63. Next, in S64, the work 50 is removed from the chamber 15 by the operator, and this control process ends.

In the present embodiment, as in the fifth embodiment, the water in the graduated cylinder 25 is sucked into the water storage tank 23, so that the pipe in the graduated cylinder 25 and the water in the graduated cylinder 25 are in contact with each other. It will be necessary.
Also in the seventh embodiment, since the medium does not come into direct contact with water, highly accurate leakage measurement is possible even with a water-soluble medium that dissolves in water.

<Other embodiments>
In each of the embodiments described above, the fluid sealed in the workpiece 50 or the chamber 15 is DME, but other liquids or gases such as air may be used. Further, the liquid stored in the water storage tank 23 is not limited to water.

  In each of the above embodiments, the electronic balance 26 and the camera 27 are provided. However, any one of them may be provided. When calculating the leak amount from the mass, the electronic balance 26 can be provided. When calculating the leak amount from the volume, the camera 27 can be provided.

  In the calculation control of the correction amount Δq by the measurement master 64 of the second embodiment, the measurement master 64 is attached in S11-2 and the measurement master 64 is detached in S25-2 in FIG. 6, but the measurement master 64 is attached. You can leave it. In this case, when calculating the leakage amount of the workpiece 50, the leakage amount control of the workpiece can be performed by blocking the flow path in the sixth pipe by the on-off valve.

  Alternatively, the correction amount Δq may be obtained by using a calibration master that has substantially the same configuration as the workpiece 50 and is airtight and has no leakage or has a known leakage amount. In this case, using the inspection apparatus 101 of the first embodiment, using the calibration master instead of the inspection work 50, the leakage amount measured by actual measurement and the known leakage amount are controlled by the same control as the leakage measurement control shown in FIG. The correction amount Δq can be obtained from the comparison with the leakage amount.

  In each of the above embodiments, the lower end of the third portion 36 of the connection pipe 24 is in contact with the liquid in the graduated cylinder 25. However, in the form in which the volume of the pack 18 is increased during the inspection, the liquid is not necessarily in contact with the liquid. There is no need. You may implement as a form which the water for a volume increase dripped in the measuring cylinder 25 from the lower end of the connection piping 24. FIG.

  In each of the above embodiments, a confirmation window may be provided in the water storage tank 23 so that the operator can visually confirm the volume change of the pack 18.

  In each of the above embodiments, the work 50 is an automobile part such as a common rail or an injector pump. However, the work 50 is not limited to an automobile part, but may be various as long as it has a fluid storage chamber inside and requires internal airtightness. The workpiece can be applied to this inspection apparatus.

  The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from the spirit of the invention.

10: Pressurizing unit 15: Chamber 18: Pack (volume variable member)
23 ・ ・ ・ Water tank (liquid container)
24 ... Connection piping 25 ... Female cylinder (measuring container)
40: Control unit 50: Workpiece (inspection object)
51... Fluid storage chamber 101...

Claims (10)

An airtight leak inspection apparatus for inspecting airtightness of an inspection object (W) having a fluid storage chamber (51),
A pressurizing unit (10) for supplying a fluid to the fluid storage chamber or into a chamber (15) for storing the inspection object and applying a predetermined test pressure (Pt);
A constant volume liquid container (23) filled with liquid;
A volume variable member (18) that is immersed in the liquid container, communicates with the fluid storage chamber or the chamber, and changes its outer shape following a change in internal pressure;
A measuring container (25) communicating with the liquid container via a connecting pipe (24) filled with the liquid;
A measuring unit (26, 27) for measuring a liquid change amount (ΔM) in the measurement container that changes in response to a volume change of the volume variable member in the liquid container;
A control unit (40) for calculating a leakage amount (ΔQ) of the inspection object based on a measurement value (M1) by the measurement unit;
An airtight inspection apparatus comprising:   The hermetic leak inspection apparatus according to claim 1, wherein the control unit controls the pressurizing unit to calculate the leakage amount based on the test pressure and the measured value. The control unit has a correction amount (Δq determined in advance by an inspection when the pressurizing unit pressurizes the measurement master (64) whose master leak amount (ΔQ _m ) when the test pressure is applied is known. The airtight leakage inspection apparatus according to claim 1, wherein the leakage amount (ΔQ _hosei ) is calculated in consideration of   The volume of the said volume variable member increases when the said pressurization part supplies the said fluid at the time of a test | inspection, and there exists a leak in the said fluid storage chamber. The described airtight leak inspection device. The chamber communicates with the variable volume member;
The hermetic leak inspection device according to claim 4, wherein the pressurizing unit supplies the fluid to the fluid storage chamber of the inspection object stored in the chamber. A suction part (22) for sucking the inside of the variable volume member;
The airtight leak inspection apparatus according to claim 5, wherein the control unit controls the suction unit so as to reduce the volume of the volume variable member that has increased due to leakage of the fluid from the fluid storage chamber. The fluid storage chamber of the inspection object communicates with the pressurizing unit on the upstream side in the fluid supply direction, and communicates with the volume variable member on the downstream side in the supply direction.
The hermetic leak inspection device according to any one of claims 1 to 3, wherein the pressurizing unit supplies the fluid to the fluid storage chamber and the volume variable member. Temperature detection means (65) for detecting the temperature of the liquid in the liquid container,
The airtight leak test according to any one of claims 1 to 7, wherein the control unit calculates the leak amount in consideration of a temperature change amount (ΔT) detected by the temperature detecting means. apparatus. A pressurizing unit (10) for supplying a fluid to a fluid storage chamber formed inside the inspection object (W) or a chamber (15) for storing the inspection object and applying a predetermined test pressure (Pt). )When,
A constant volume liquid container (23) filled with liquid;
A volume variable member (18) that is immersed in the liquid container, communicates with the fluid storage chamber or the chamber, and changes its outer shape following a change in internal pressure;
A measuring container (25) communicating with the liquid container via a connecting pipe (24) filled with the liquid;
A measuring unit (26, 27) for measuring a liquid change amount (ΔM) in the measurement container that changes in response to a volume change of the volume variable member in the liquid container;
A control unit (40) for controlling the pressurizing unit;
An airtight leak inspection method using an airtight leak inspection apparatus comprising:
A pressurizing step (S12, S13, S14) by the pressurizing unit;
Based on the difference between the start measurement value (M ₀ ) at the start of the inspection measured by the measurement unit and the end measurement value (M1) at the end of the inspection, the control unit leaks the inspection object. A leakage amount calculating step (S19) for calculating (ΔQ);
Including airtight leak inspection method. In the inspection when the pressurizing unit pressurizes the measurement master (64) having a known master leakage amount (ΔQ _m ) indicating leakage when the test pressure is applied, the actual measurement value (ΔM) obtained A correction amount calculating step (S19-2) in which the control unit calculates a correction amount (Δq) based on a difference from a true amount (ΔM _m ) calculated from the master leakage amount;
The airtight leak inspection method according to claim 9, wherein, in the leak amount calculation step, the control unit calculates a leak amount (ΔQ) of the inspection object in consideration of the correction amount.

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