Air leak test device and method

Abstract

To provide a new type air leak test device capable of easily setting a reference value for quality determination.SOLUTION: An air leak test device includes a set pressure supply unit 1, a main passage 2 connected to the set pressure supply unit 1, a work capsule 10 connected to an end of the main passage 2, a pressure supply valve 20 and an orifice 30 provided in the main passage 2, an absolute pressure sensor 50 that detects a pressure in the work capsule 10, and a controller 60. The controller 60 executes a pressure supply process for communicating the set pressure supply unit 1 with the work capsule 10 by controlling the pressure supply valve 20, and a closure maintaining process for maintaining the closed state of the work capsule. In the leak test of an inspection object, the quality of the inspection object is determined based on comparison with the average pressure value of the non-defective product pressure data.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a new type of air leak test device and method. [Background technology]

[0002] As shown in Patent Document 1, differential pressure air leak testing devices are widely used as air leak testing devices for determining the hermeticity of hollow products (test objects), particularly the presence or absence of minute leaks. This differential pressure air leak testing device will be briefly described using an example in which a positive test pressure is supplied to a hollow test object without an opening. The upstream end of the main passage is connected to a pressure source via a regulator, and the downstream end is branched, with a work capsule containing the test object connected to one branch and a reference container connected to the other branch. Two ports of a differential pressure sensor are connected to these branch paths, respectively.

[0003] In the differential pressure type air leak test device, the following steps are carried out in order. (1) Pressurization process to supply test pressure to the work capsule and reference vessel. (2) An equilibration process in which the work capsule and reference vessel are isolated from the pressure source and the pressure in both vessels is stabilized. (3) A detection process in which a differential pressure sensor detects the differential pressure between the work capsule and the reference container, and determines whether or not there is a leak in the test object based on this differential pressure. (4) Exhaust process. The differential pressure air leak test device described above requires a pressurization process and an equilibration process before the detection process. Furthermore, during the pressurization process, it takes time for the pressure downstream of the regulator to reach the test pressure. This is because as the test pressure is approached, the regulator opening becomes smaller, restricting the flow rate and slowing the pressure rise. As a result, it may take a total of 15 seconds: 7 seconds for the pressurization process, 2 seconds for the equilibration process, 5 seconds for the detection process, and 1 second for the exhaust process, which places a limit on how quickly a single leak test can be completed.

[0004] The new direct pressure air leak test device disclosed in Patent Document 2 by the present applicant comprises a set pressure supply unit and a main passage, with the set pressure supply unit connected to the base end of the main passage. A work capsule that seals the test object is connected to the end of the main passage. A pressure supply valve and an orifice are provided in the main passage. The pressure inside the work capsule is detected by an absolute pressure sensor. In the case where the set pressure supply unit is a positive pressure, a pressure supply process is carried out in which air is circulated through the orifice by opening the pressure supply valve, thereby increasing the pressure inside the work capsule, and a closed maintenance process is carried out in which the pressure supply valve is closed after a predetermined time has elapsed, thereby cutting off communication between the set pressure supply unit and the work capsule and maintaining the closed state of the work capsule.

[0005] During the pressure supply process, the pressure inside the work capsule rises almost linearly, so the time required for the pressure supply process is short. Also, since the accumulated leaks during the pressure supply process and the closed maintenance process are reflected in the detected pressure, leaks in the test object can be accurately detected even if the time for both processes is short. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] WO2017 / 208543 publication [Patent Document 2] Japanese Patent Publication No. 2021-196229 Summary of the Invention [Problem to be solved by the invention]

[0007] In the air leak test device of Patent Document 2, setting a threshold value for determining whether or not a test object has a leak (whether or not the product is good) is complicated, and requires experience and time. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides an air leak test device comprising: a set pressure supply unit that supplies a set pressure; a main passage having a base end connected to the set pressure supply unit and a terminal end connected to an object to be tested or a work capsule that seals the object to be tested; a pressure supply valve that is provided in the main passage and controls communication between the set pressure supply unit and the object to be tested or the work capsule; a flow rate restricting unit that is provided in the main passage and restricts the flow rate of air passing through the main passage when the pressure supply valve is open; a pressure sensor that detects the pressure inside the object to be tested or the work capsule; and a control and calculation unit, Prior to the leak test of the test object, the control and calculation unit executes a non-defective product pressure data acquisition process for a plurality of non-defective products of the same standard as the test object and without leaks, and in this non-defective product pressure data acquisition process, the pressure supply valve is opened to communicate between the set pressure supply unit and the test object or the work capsule, thereby starting the supply of pressure into the test object or the work capsule, and the pressure supply valve is closed to interrupt the communication between the set pressure supply unit and the test object or the work capsule, thereby terminating the pressure supply; Following the pressure supply step, a closed state maintaining step is carried out in which the pressure supply valve is maintained in a closed state and the inspection object or work capsule is maintained in a closed state, and non-defective product pressure data including an average pressure value for a plurality of non-defective products is acquired based on the detected pressure from the pressure sensor at at least one specific timing during the time periods of the pressure supply step and the closed state maintaining step, The control and calculation unit executes the pressure supply process and the closed maintenance process during the leak test of the test object, and determines whether the test object is a good product without leaks based on a comparison of the detected pressure from the pressure sensor at the specific timing with the average pressure value of the good product pressure data.

[0009] According to the above-described configuration, it is possible to easily set a criterion for determining whether or not a leak is present in the test object by comparing it with pre-acquired non-defective pressure data.

[0010] Preferably, when the test object is determined to be a non-defective product in the leak test of the test object, the control and calculation unit updates the non-defective product pressure data based on the detected pressure of the test object. According to this configuration, the influence of heat accumulation due to repeated leak tests and the influence of the external temperature can be suppressed or canceled, and an accurate pass / fail determination can be made.

[0011] The non-defective pressure data is preferably updated by a moving average or a weighted average, and the detection output of the latest inspection object that has been judged to be non-defective is weighted.

[0012] Preferably, acquiring the non-defective pressure data in the non-defective pressure data acquisition process includes creating a normal distribution of detected pressure values, and updating the non-defective pressure data in the leak test of the test object includes updating the normal distribution of the non-defective pressure data. The control and calculation unit determines that the test object is a good product when the detected pressure detected by the pressure sensor at the specific timing during the leak test is within a range obtained by multiplying the standard deviation σ in the normal distribution by a first specified magnification, and determines that the test object has a leak when the detected pressure exceeds the range. According to this configuration, by setting in advance the first specified magnification by which the standard deviation σ of the normal distribution should be multiplied, it is possible to automatically set a substantial threshold value for determining whether the product is good or bad.

[0013] Preferably, when the test object is determined to be a non-defective product in the leak test of the test object, the control and calculation unit updates the non-defective product pressure data based on the detected pressure only if the detected pressure is within a range obtained by multiplying the standard deviation σ in the normal distribution by a second specified magnification, the second specified magnification being smaller than the first specified magnification. According to this configuration, high-precision non-defective pressure data can be ensured by updating the non-defective pressure data by excluding detected pressures that are significantly different from the median mean value of the normal distribution from the detected pressures of test objects judged to be non-defective.

[0014] In one embodiment, the specific timing is set to immediately before the end of the closed-state maintaining step. According to this configuration, if there is a leak in the test object, the pass / fail determination is made based on the detected pressure that reflects the maximum accumulated leak amount, so that the pass / fail determination can be made with high reliability. In another embodiment, the specific timing is set to immediately before the end of the closed state maintaining step and at the time of closing the pressure supply valve. With this configuration, the specific timing includes the time of closing the pressure supply valve, so that a pass / fail determination can be made early for a test object with a relatively large leak.

[0015] The specific timing is set for each unit time in a predetermined time period from the start of the pressure supply process or from the middle of the pressure supply process to the end of the closed-state maintaining process, In the non-defective pressure data acquisition process, the control and calculation unit creates the non-defective pressure data based on the detected pressure from the pressure sensor for each unit time of the specified time period, and in the leak test of the test object, reads the detected pressure from the pressure sensor for each unit time of the specified time period, determines whether the test object is good or bad, and updates the non-defective pressure data. According to this configuration, updating of the non-defective pressure data and determining the quality of the test object can be performed continuously during a predetermined time period from the start of the pressure supply process or from the middle of the pressure supply process until the end of the closed maintenance process.

[0016] In the above embodiment, preferably, when the control and calculation unit determines that the test object has a leak during the leak test, it executes a step of releasing the main circuit to the atmosphere, thereby terminating the leak test of the test object. According to this configuration, the time required for leak testing of an object to be inspected for leaks can be reduced.

[0017] In another aspect of the present invention, there is provided an air leak testing method, comprising: An air leak test device is provided which includes: a set pressure supply unit which supplies a set pressure; a main passage which has a base end connected to the set pressure supply unit and a terminal end connected to an object to be inspected or a work capsule which seals the object to be inspected; a pressure supply valve which is provided in the main passage and controls communication between the set pressure supply unit and the object to be inspected or the work capsule; a flow rate restricting unit which is provided in the main passage and restricts the flow rate of air passing through the main passage when the pressure supply valve is open; and a pressure sensor which detects the pressure inside the object to be inspected or the work capsule; Prior to the leak test of the test object, a non-defective pressure data acquisition process is carried out for a plurality of non-defective products of the same standard as the test object and free of leaks, and in this non-defective pressure data acquisition process, the pressure supply valve is opened to communicate between the set pressure supply unit and the test object or the work capsule, thereby starting the supply of pressure into the test object or the work capsule, and the pressure supply valve is closed to interrupt the communication between the set pressure supply unit and the test object or the work capsule, thereby terminating the pressure supply, and a closed state maintenance process is carried out following the pressure supply process, in which the pressure supply valve is maintained in a closed state, and the test object or the work capsule is maintained in a closed state, and non-defective pressure data including an average pressure value for the plurality of non-defective products is acquired based on the detected pressure from the pressure sensor at at least one specific timing during the time periods of the pressure supply process and the closed state maintenance process, In the leak test of the test object, the pressure supply step and the closed maintenance step are executed, and based on a comparison of the detected pressure from the pressure sensor at the specific timing with an average pressure value of the non-defective product pressure data, it is determined whether the test object is a non-defective product without leaks; When the test object is determined to be a non-defective product in the leak test of the test object, the non-defective product pressure data is updated based on the detected pressure of the test object; The acquisition of the good product pressure data in the good product pressure data acquisition process includes creating a normal distribution of detected pressure values, and the updating of the good product pressure data in the leak test of the test object includes updating the normal distribution of the good product pressure data. [Effects of the Invention]

[0018] According to the present invention, by using the non-defective pressure data, it is possible to easily set standards for determining whether an object to be inspected is good or bad. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a circuit diagram of an air leak test device according to an embodiment of the present invention. [Figure 2] 10 is a graph showing a change in pressure inside a work capsule during a non-defective product pressure data acquisition process performed by the air leak test device. [Figure 3] 1 is a graph showing the pressure change inside a work capsule during a leak test of an object to be tested, where curve A shows good product pressure data, curve B shows the change in detected pressure when the object to be tested has a small leak, and curve C shows the change in detected pressure when the object to be tested has a large leak. [Figure 4] 10 is a graph schematically showing the change in pressure difference between curve A and curve B. DETAILED DESCRIPTION OF THE INVENTION

[0020] <Air leak test device configuration> An air leak test device according to one embodiment of the present invention will be described below with reference to Fig. 1. The air leak test device includes a set pressure supply unit 1 consisting of a pressure source 1a and a regulator 1b, and a main passage 2. In this embodiment, the set pressure supply unit 1 supplies a positive set pressure. A base end 2a of the main passage 2 is connected to the regulator 1b of the set pressure supply unit 1. A work capsule 10 is connected to an end 2b of the main passage 2. A pressure gauge 3, a pressure supply valve 20, and an orifice 30 (flow rate control unit) are provided in the main passage 2, and a pressure release valve 40 is connected downstream of the pressure supply valve 20 and the orifice 30.

[0021] The work capsule 10 includes a capsule body 11, which is, for example, in the shape of a container with an open upper end for accommodating an inspection object W, and a lid 12. The capsule body 11 is movable between a carry-in / carry-out position (not shown) and an inspection position below the lid 12. When the capsule body 11 is in the inspection position, the capsule body 11 and the lid 12 are clamped by a clamping mechanism, and the inspection object W is sealed in the accommodation space of the capsule body 11.

[0022] The air leak test device further includes a high-resolution (1 Pa) absolute pressure sensor 50 (direct pressure sensor; pressure sensor) for detecting the pressure of the work capsule 10, and a controller 60 (control and calculation unit). The absolute pressure sensor 50 is connected to the work capsule 10 or the main passage 2 downstream of the pressure supply valve 20 and the orifice 30. The controller 60 controls the work capsule 10, the pressure supply valve 20, and the pressure release valve 40, reads the detected pressure from the absolute pressure sensor 50, and determines whether or not the test object W is leaking (determines whether or not the test object is a non-defective product).

[0023] <Valve control overview> With the work capsule 20 connected to the end 2b of the main passage 2, the controller 60 executes a pressure supply step, a closed state maintenance step, and an exhaust step by valve control, which will be described below.

[0024] In the initial state, the pressure supply valve 20 is closed and the pressure release valve 40 is open, so that the work capsule 10 and the main passage 2 communicating with this work capsule 10 are at atmospheric pressure. <Pressure supply process> The pressure release valve 40 is closed and then the pressure supply valve 20 is opened. The time point at which the pressure supply valve 20 opens is indicated by the symbol t0 in Figures 2 and 3. The pressure supply process is the period from when the pressure supply valve 20 opens at time t0 until when it closes at time t1, which will be described later. When the pressure supply valve 20 opens, the set pressure from the set pressure supply unit 1 is applied to the orifice 30, and air flows through the orifice 30 and is supplied to the main passage 2 and the work capsule 10. The time required for this pressure supply process is approximately 2 seconds.

[0025] During the pressure supply process from the pressure supply start time t0 to the closing operation time t1 of the pressure supply valve 20, the pressure inside the work capsule 10 rises almost linearly from atmospheric pressure. If the inspection object W is a non-defective product, it reaches pressure Pa in a short time, as shown in Figures 2 and 3. The closing operation time t1 is set so that pressure Pa is approximately 100 kPa higher than atmospheric pressure, but the set pressure output from the pressure setting unit 1 is approximately 100 kPa higher than this pressure Pa. Because a substantially constant amount of air flows through the orifice 30 and pressure supply is performed by opening and closing the pressure supply valve 20, the pressure inside the work capsule 10 rises linearly as described above. In other words, unlike the test pressure supply process in a differential pressure leak test device, the pressure does not follow a saturation curve where the pressure rise becomes gentler as the test pressure is approached. As a result, the time for the pressure supply process can be shortened.

[0026] <Closing maintenance process> At time t1, a set time (for example, 2 seconds) after pressure supply start time t0, the pressure supply valve 20 is closed, thereby blocking communication between the set pressure supply unit 1 and the warp capsule 10 and maintaining the closed state of the work capsule 10. When the pressure supply valve 20 closes at time t1 and transitions to the closed state maintenance process, the pressure inside the work capsule 10 begins to decrease from the peak pressure near the closing operation time t1 due to cooling after adiabatic compression, etc. Immediately after the closing operation time t1, the pressure drop is relatively large, and then gradually decreases more slowly. The time required for this closed state maintenance process is approximately 4 seconds.

[0027] <Exhaust process> At time t2, a set time (for example, 4 seconds) after the closing operation of the pressure supply valve 20 at time t1, the pressure release valve 40 is opened and the work capsule 10 is released to the atmosphere (exhaust process). During this exhaust process, the pressure inside the work capsule 10 drops rapidly and returns to atmospheric pressure. This exhaust process takes approximately 1 second. As mentioned above, the time required for the entire process, including the pressure supply process, closed maintenance process, and exhaust process, is approximately 7 seconds, which is about half the time required for a typical differential pressure air leak test.

[0028] <Process for acquiring pressure data on non-defective products> Prior to executing a leak test on the inspection object W, a non-defective pressure data acquisition process is executed. In this non-defective pressure data acquisition process, a plurality of leak-free non-defective products (e.g., several tens of products) of the same specifications as the inspection object W are prepared, and the pressure supply process, closed maintenance process, and exhaust process described above are executed for these non-defective products. In this non-defective pressure data acquisition process, the pressure inside the work capsule 10 changes to follow the curve A in FIG. 2 or a curve approximating this curve A.

[0029] The controller 60 reads the detected pressure from the absolute pressure sensor 50 every unit time (for example, 0.1 seconds) during the time period from the start time t0 of the pressure supply process or from partway through the pressure supply process to the end time t2 of the closed state maintenance process, calculates the average value from several tens of detected pressures every unit time, creates a normal distribution curve centered on this average value every unit time, and stores it as initial non-defective pressure data. If the average value of the detected pressures for each unit time is plotted, curve A in Figure 2 is drawn.

[0030] <About the air leak test to be inspected> Next, the air leak test of the inspection object W will be described with reference to Fig. 3. Curve A in Fig. 3 is a curve based on non-defective pressure data already stored in the controller 60, and is the same as curve A in Fig. 2. This non-defective pressure data is updated each time the air leak test of the inspection object W is repeated, as will be described later.

[0031] In the air leak test of the test object W, the sequence control of the valves 20 and 40 is performed in the same manner as described above, and the pressure supply step, the closed state maintenance step, and the exhaust step are performed. If there is a leak in the test object W, some of the air that flows into the work capsule 10 through the orifice 30 during the pressure supply process will enter the internal space of the test object W, thereby suppressing the pressure rise inside the work capsule 10. Therefore, as shown by curves B and C in Figure 3, the pressure is lower than that of curve A during the pressure supply process, and the peak values ​​Pb and Pc at the time t1 when the pressure supply valve 20 closes are also lower than the peak value Pa of the non-defective product pressure data. If the test object W has a relatively small leak, the pressure drop is smaller than that of curve A of the non-defective product pressure data, as shown by curve B, and if the test object W has a large leak, the pressure drop is larger as shown by curve C.

[0032] In the closed state maintenance process after the time t1 of the closing operation of the pressure supply valve 20, for the test object W with a relatively small leak, the intrusion (leakage) of pressurized air into the test object W continues, and therefore, as shown in curve B, the pressure drop increases accordingly compared to the non-defective pressure data A. Figure 4 shows a schematic diagram of the increase over time in the pressure difference inside the work capsule 10 between the non-defective pressure data shown by curve A and the test object with a leak shown by curve B. In the test object W with a large leak, the intrusion (leakage) of pressurized air into the test object W has almost finished, so the pressure inside the work capsule 10 decreases along a curve similar to the curve A of the good product pressure data, as shown by curve C. However, since the peak value Pc at the closing operation time t1 is low, a large pressure difference from the good product is maintained.

[0033] In this embodiment, in the leak test of the inspection object W, the controller 60 reads the detected pressure from the absolute pressure sensor 50 at unit time intervals during a predetermined time period from time t0 of the pressure supply process or from the middle of the pressure supply process to time t2 at which the closed maintenance process ends, in the same manner as when obtaining good product pressure data, and compares it with the good product pressure data at the same time.

[0034] <Specific method for determining pass / fail> If the detected pressure for the test object W falls within a range obtained by multiplying the standard deviation σ from the center value (average value) of the normal distribution of pressure data for non-defective products at the same time by a first specified magnification factor A1, the test object W is determined to be a non-defective product with no leaks. If the detected pressure does not fall within this range, the test object W is determined to be a non-defective product with a leak. σ·A1 is, for example, ±6σ. In this embodiment, if the test object W has a leak, the detected pressure will be lower than the center value of the non-defective product pressure data. Therefore, if the detected pressure falls within a range of -6σ or less, the test object W may be determined to have a leak, and if the detected pressure falls within a range of -6σ or more, the test object W may be determined to be a non-defective product. The first specified magnification factor A1 is not limited to "6" and can be set within a range of, for example, "4 to 8."

[0035] As described above, the quality of the inspection object W is judged based on the normal distribution of the pressure data of non-defective products. The standard for the quality judgment is automatically set by simply acquiring the initial pressure data of non-defective products and setting the first specified magnification, so setting this standard does not require skill or effort.

[0036] In this embodiment, the pass / fail judgment is made by comparing the non-defective pressure data with the detected pressure every unit time during a predetermined time period from the pressure supply process to the closed maintenance process, and the exhaust process is executed at time t2. The final pass / fail judgment of the inspection object W may be made just before the end of the closed maintenance process. At this timing, as shown in FIG. 4, if there is a leak in the inspection object W, the difference between the non-defective pressure data A and the detected pressure of the inspection object W will be at its maximum, and a highly accurate pass / fail judgment can be made. Also, In the pass / fail judgment for each unit time, if it is judged that there is a leak in the inspection object W, this judgment may be made the final judgment, and the pass / fail judgment thereafter may be omitted.

[0037] <Update of good product pressure data> When the leak test is repeated, the detected pressure when the test object is a pass-quality product also changes due to changes in heat accumulation in the device itself and changes in the environmental temperature. Therefore, in this embodiment, when the test object W is determined to be a pass-quality product in the above-mentioned leak test, the detected pressure of this test object W per unit time is used to update the pass-quality product pressure data per unit time, thereby suppressing or canceling the effects of heat accumulation and changes in the environmental temperature, thereby making it possible to accurately determine whether the test object is pass-quality or not.

[0038] The non-defective pressure data is updated using a moving average or weighted average to weight the detected pressure of the latest inspection target W. The update of the non-defective pressure data includes not only updating the average value but also updating the normal distribution.

[0039] Even for the detected pressures of test objects W judged to be good, detected pressures far from the median (average value) of the normal distribution of good-quality pressure data may be excluded, and only detected pressures close to the median may be selected and used to update the good-quality pressure data, thereby increasing the reliability of the good-quality pressure data. In other words, only if the detected pressure of a test object W judged to be good falls within a range obtained by multiplying the standard deviation σ from the median value (average value) of the normal distribution of good-quality pressure data at the same time by a second specified magnification A2, this detected pressure is used to update the good-quality pressure data. In Figure 2, this range of detected pressures is schematically shown by a dotted line. σ·A2 is set in the range of ±1σ to ±3σ. The second specified magnification A2 is smaller than the first specified magnification A1.

[0040] In this embodiment, since the absolute pressure sensor 50 is used, the mass flow rate of the leaked air can also be calculated from the pressure difference between the detected pressure and the pressure data of the non-defective product, and the environmental temperature.

[0041] Other embodiments of the present invention will be described below. In the following description, the parts that will be omitted are the same as those in the preceding embodiment. Second Embodiment In the second embodiment, similar to the first embodiment, the pass / fail judgment is performed by comparing the non-defective pressure data with the detected pressure for each unit time during a predetermined time period from the pressure supply step to the closed maintenance step, and if it is determined that there is a leak in the test object based on one or more pass / fail judgments during the pressure supply step or the closed maintenance step, the exhaust step is performed immediately after this judgment and the leak test is terminated. In this embodiment, the leak test time for the test object with a leak can be shortened.

[0042] Third Embodiment In the third embodiment, the pass / fail judgment is not made for each unit time during a predetermined time period from the pressure supply step to the closed state maintaining step, but is made at a time (specific timing) immediately before the end of the closed state maintaining step. If there is a leak in the test object W, the amount of leakage will be maximized immediately before the time t2 when the atmosphere release valve 40 opens, and the pressure difference between the pass / fail pressure data and the detected pressure will be maximized accordingly (see FIG. 4), making it possible to accurately judge whether the test object W is pass / fail. In this embodiment, pass / fail pressure data is created in the same way as in the above embodiments, and is updated with the detected pressure of the test object W that has been judged to be pass / fail, only at the specific timing.

[0043] In the fourth embodiment, the pass / fail determination is performed at the time of the closing operation of the pressure supply valve 20, that is, at the boundary between the pressure supply step and the closed state maintaining step (first specific timing), and at the time immediately before the end of the closed state maintaining step (second specific timing). In this embodiment, the pass / fail pressure data is also acquired only at the first and second specific timings. At the first specified timing, if the leak in the test object is large, the pressure difference between the detected pressure and the non-defective product pressure data A will be large, as shown by curve C in Figure 3, making it possible to accurately determine that the test object has a leak. Immediately after this determination that a leak exists, the exhaust process may be performed to end the leak test.

[0044] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. The orifice may be omitted. In this case, the narrow internal passage of the pressure supply valve 20 serves to restrict the amount of air flow to a certain level.

[0045] A hollow test object may be directly connected to the end of the main passage without using a work capsule. For example, when performing a leak test on a hollow test object with an opening, such as a fuel tank or a plastic bottle, the opening is directly connected to the end of the main passage.

[0046] The set pressure supply unit may be a negative pressure source. The operation when the set pressure is negative can be explained using the graphs in Figures 2 and 3, which are inverted around atmospheric pressure. The quality may be determined by comparing the difference between the average value of the non-defective pressure data and the detected pressure with a threshold value without using a normal distribution. [Industrial Applicability]

[0047] The present invention can be applied to an air leak test device. [Explanation of symbols]

[0048] 1 Set pressure supply unit 2 Main passage 10 Work Capsules 20 Pressure supply valve 30 Orifice (pressure limiting part) 40 Pressure Relief Valve 50 Absolute pressure sensor (pressure sensor) 60 Controller (control and calculation unit) W Inspection subject

Claims

1. a set pressure supply unit that supplies a set pressure; a main passage having a base end connected to the set pressure supply unit and a distal end connected to an inspection object or a work capsule that seals the inspection object; a pressure supply valve provided in the main passage for controlling communication between the set pressure supply unit and the inspection object or the work capsule; a flow rate restricting portion provided in the main passage and configured to restrict the flow rate of air passing through the main passage when the pressure supply valve is open; a pressure sensor for detecting the pressure inside the inspection object or the work capsule; a control and calculation unit; In an air leak test device comprising: The control and calculation unit executes a non-defective pressure data acquisition step for a plurality of non-defective products having the same standard as the test object and no leaks, prior to the leak test of the test object, and in this non-defective pressure data acquisition step, a pressure supply process in which the pressure supply valve is opened to communicate between the set pressure supply unit and the inspection object or the work capsule, thereby starting the supply of pressure into the inspection object or the work capsule, and the pressure supply valve is closed to block the communication between the set pressure supply unit and the inspection object or the work capsule, thereby terminating the pressure supply; Following the pressure supply step, a closed state maintaining step of maintaining the closed state of the pressure supply valve and maintaining the closed state of the inspection object or work capsule; Run acquiring non-defective product pressure data including an average pressure value for a plurality of non-defective products based on the detected pressure from the pressure sensor at at least one specific timing during the pressure supply step and the closed-off maintaining step; The control and calculation unit executes the pressure supply process and the closed maintenance process in the leak test of the test object, and determines whether the test object is a non-defective product without leaks based on a comparison of the detected pressure from the pressure sensor at the specific timing with an average pressure value of the non-defective product pressure data.

2. 2. The air leak test device according to claim 1, wherein the control and calculation unit updates the good-product pressure data based on the detected pressure of the test object when the test object is determined to be a good product in the leak test of the test object.

3. 3. The air leak test device according to claim 2, wherein the non-defective product pressure data is updated by a moving average or a weighted average.

4. 3. The air leak test device according to claim 2, wherein acquiring the non-defective pressure data in the non-defective pressure data acquisition step includes creating a normal distribution of detected pressure values, and updating the non-defective pressure data in the leak test of the test object includes updating the normal distribution of the non-defective pressure data.

5. 5. The air leak test device according to claim 4, wherein the control and calculation unit determines that the test object is a non-defective product when the detected pressure detected by the pressure sensor at the specific timing in the leak test of the test object is within a range obtained by multiplying the standard deviation σ of the normal distribution by a first specified magnification, and determines that the test object has a leak when the detected pressure exceeds the range.

6. 6. The air leak test device according to claim 5, wherein the control and calculation unit, when determining that the test object is a non-defective product in the leak test of the test object, updates the non-defective product pressure data based on the detected pressure only if the detected pressure is within a range obtained by multiplying the standard deviation σ in the normal distribution by a second specified magnification, and the second specified magnification is smaller than the first specified magnification.

7. 2. The air leak test device according to claim 1, wherein the specific timing is set to immediately before the end of the closed state maintaining step.

8. 2. The air leak test device according to claim 1, wherein the specific timing is set to immediately before the end of the closed state maintaining step and during the closing operation of the pressure supply valve.

9. The specific timing is set for each unit time in a predetermined time period from the start of the pressure supply process or from the middle of the pressure supply process to the end of the closed-state maintaining process, The control and calculation unit In the non-defective pressure data acquisition step, the non-defective pressure data is generated based on the pressure detected by the pressure sensor for each unit time of the predetermined time period; 3. The air leak test device according to claim 2, wherein, in the leak test of the test object, the detected pressure from the pressure sensor is read for each unit time of the predetermined time period, a pass / fail judgment is made on the test object, and the pass / fail pressure data is updated.

10. 10. The air leak test device according to claim 8, wherein the control and calculation unit, when determining that the test object has a leak during the leak test, executes a step of releasing the main circuit to the atmosphere, thereby terminating the leak test of the test object.

11. a set pressure supply unit that supplies a set pressure; a main passage having a base end connected to the set pressure supply unit and a distal end connected to an inspection object or a work capsule that seals the inspection object; a pressure supply valve provided in the main passage for controlling communication between the set pressure supply unit and the inspection object or the work capsule; a flow rate restricting portion provided in the main passage and configured to restrict the flow rate of air passing through the main passage when the pressure supply valve is open; a pressure sensor for detecting the pressure inside the inspection object or the work capsule; An air leak test device equipped with Prior to the leak test of the test object, a non-defective pressure data acquisition step is performed on a plurality of non-defective products of the same standard as the test object and free of leaks, and in this non-defective pressure data acquisition step, a pressure supply process in which the pressure supply valve is opened to communicate between the set pressure supply unit and the inspection object or the work capsule, thereby starting the supply of pressure into the inspection object or the work capsule, and the pressure supply valve is closed to block the communication between the set pressure supply unit and the inspection object or the work capsule, thereby terminating the pressure supply; Following the pressure supply step, a closed state maintaining step of maintaining the closed state of the pressure supply valve and maintaining the closed state of the inspection object or work capsule; Run acquiring non-defective product pressure data including an average pressure value for a plurality of non-defective products based on the detected pressure from the pressure sensor at at least one specific timing during the pressure supply step and the closed-off maintaining step; In the leak test of the test object, the pressure supply step and the closed maintenance step are executed, and based on a comparison of the detected pressure from the pressure sensor at the specific timing with an average pressure value of the non-defective product pressure data, it is determined whether the test object is a non-defective product without leaks; When the test object is determined to be a non-defective product in the leak test of the test object, the non-defective product pressure data is updated based on the detected pressure of the test object; an air leak testing method characterized in that acquiring the good product pressure data in the good product pressure data acquisition step includes creating a normal distribution of detected pressure values, and updating the good product pressure data in the leak test of the test object includes updating the normal distribution of the good product pressure data.

Images