JPH0692921B2 - Method for measuring internal volume of leaked tare and amount of leak and measuring device using this measuring method - Google Patents

Description

The present invention relates to a method for measuring the internal volume of a tare that leaks, such as an airbag for an automobile, a method for measuring the amount of leakage of a tare that leaks, and these methods. The present invention relates to a measuring device that operates by using.

"Prior Art" As is well known, an airbag developed as a shock absorber for automobiles instantly fills the tare with gas when an impact is detected, creating a cushion between the occupant's body and vehicle equipment such as the steering wheel. At the same time as forming, the weight of the occupant's body is sensed and the gas inside the tare is released at an appropriate speed. Acts to protect the occupant's body.

In this way, the airbag performs gas filling and gas discharging operations from the start to the end of the impact.

Here, if the amount of released gas is too large, the gas is released from the airbag before the impact force is relieved, and the occupant cannot be protected.

Further, when the amount of released gas is excessively small, the reaction force from the airbag becomes large, which may cause the occupant's body to bounce back.

For this reason, the airbag is required to have an appropriate amount of leakage and to have a predetermined internal volume so that the state of gas leakage can be maintained for a required time.

[Problems to be Solved by the Invention] As described above, the airbag is required to have an appropriate leakage and a predetermined internal volume, and it is desired to establish an inspection method therefor.

Conventionally, the technology for measuring the internal volume of a container and the like and the technology for measuring the amount of leakage have been manufactured and sold by the applicant company, but the shape of the container does not change within the range of known technology. The purpose is to detect the presence or absence of very small leaks that should not occur.
There is no technique capable of measuring the internal volume and the amount of leakage of a measuring object that has a relatively large leakage like an airbag and has a large shape deformation.

An object of the present invention is to provide a measuring method and a measuring method capable of measuring an inner volume and a leak amount that have a relatively large amount of leakage like an airbag as described above and have a large amount of deformation and are symmetrical to measurement. The measuring device used is proposed.

[Means for Solving the Problem] In the first invention of this application, the tare to be measured is arranged in a folded state in a measuring container provided with a known gas pressure and a known internal volume, and The measuring tare has a gas pressure higher than the gas pressure in the measuring container, and gas is supplied from a gas supply source with a known internal volume, and the pressure change on the gas supply source side when the measured tare is fully inflated is measured. The amount of gas supplied to the measured tare and the amount of gas leaked from the measured tare into the measuring container is calculated, and the pressure change in the measuring container is measured. The tare with a leak was created by calculating the sum of the volume in which the tare to be measured inflates and the amount of gas leaked into the measuring container, and calculating the internal volume of the tare to be measured from the sum of these values. This method proposes a method for measuring the internal volume of.

The second invention of this application corresponds to the sum of the amount of gas supplied to the measured tare and the amount of gas leaked from the measured tare to the measuring container, which is obtained by measuring the pressure change on the gas supply source side. The amount of the gas leaked from the measured tare into the measuring container from the amount and the value of the internal volume of the measured tare calculated in the first aspect of the invention to obtain the leak amount of the measured tare. It proposes a method for measuring the amount of leakage.

According to the first invention and the second invention, the measuring means can be composed only of the pressure gauge. Since a highly accurate pressure gauge can be easily obtained, therefore, according to the present invention, the internal volume and leakage amount of the tare to be measured can be accurately measured.

The third invention of this application proposes a specific configuration of a measuring apparatus for realizing the measuring methods of the first invention and the second invention.

The characteristic configuration is a gas supply source tank capable of supplying a gas having a volume larger than the internal volume of the measured tare to the measured tare, and a first pressure gauge for measuring the pressure of the gas supply source tank. , The gas source that supplies gas to the gas supply source tank before starting the measurement to increase the gas pressure in the gas supply source tank to a desired value is shielded between the gas source and the gas supply source tank during measurement. A shut-off valve for shutting off, a measuring container having a known inner volume larger than the inner volume of the tare to be measured, a pipe for communicating between this measuring container and the gas supply tank, and a measuring container It is provided in the communication hole of the pipe formed on the inner wall,
A connecting tool for connecting the gas inlet of the tare to be measured to this communication hole, a second pressure gauge for measuring the pressure in the measurement container, and a pipe for communicating between the gas supply tank and the measurement container. An on-off valve, which is provided in the middle and is controlled to open during measurement, and an internal volume of the leaked tare and a leak amount measuring device are configured.

According to the third aspect of the present invention, the internal volume and the amount of leakage of the leaked tare can be actually measured accurately.

"Embodiment" FIG. 1 is a diagram for explaining the configuration of the measuring method and apparatus proposed in the first to third inventions of this application.

In FIG. 1, 100 is a tare to be measured, 200 is a measuring container in which the tare 100 to be measured is housed, and 300 is a tank for a gas supply source.

The gas pressure source tank 300 and the measurement container 200 have a first pressure gauge.
301 and the second pressure gauge 201 are provided, and the gas supply tank 30
It is configured to be able to measure 0 and the pressure of the gas in the measuring container 200.

The gas supply tank 300 has a known internal volume V ₁ and is previously filled with a gas having a known pressure P ₁ such as air. This gas is supplied from the gas source 500 through the shutoff valve 501.

The shutoff valve 501 is controlled to be closed when the pressure in the gas supply tank 300 reaches a predetermined pressure P ₁ .

A pipe 400 is provided between the gas supply tank 300 and the measuring container 200.
To communicate. A valve 401 is provided in the middle of the pipe 400. A connecting member 203 is provided in a communication hole of the measuring container 200 with the pipe 400, and the gas blowing port 101 of the tare 100 to be measured is connected to the connecting member 203 to connect the tare 100 to be measured to the pipe 400.

The valve 401 is closed until the start of measurement, and is controlled to open at the start of measurement so as to supply gas from the gas supply source 300 to the tare 100 to be measured, and to measure the change in pressure inside the measuring container 200 by the second pressure gauge 2
Measure with 01.

That is, the initial pressure P _A inside the measurement container 200 is set to a value smaller than the initial pressure P ₁ of the gas supply source tank 300. As an example, for example, the valve 202 is temporarily opened to the atmosphere, the inside of the measurement container 200 is set to the atmospheric pressure, and the value is set to the initial value P _A. The initial value P _A may take a pressure value other than atmospheric pressure.

Set the internal volume of the gas supply tank 300 to V ₁ and set the measuring container 2
The internal volume of 00 is set to a known value V _0, and the internal volumes V ₁ and V ₀ of these gas supply source tank 300 and measurement container 200 are the tare 100 to be measured.
The size is selected to be sufficiently larger than the inner volume x of, for example, several times.

When the gas having the pressure P ₁ is applied to the tare 100 to be measured from the gas supply tank 300, the tare 100 to be measured swells inside the measuring container 200 as shown in FIG.

When a certain time t elapses, the measured tare 100 reaches a state of being sufficiently inflated.

The values of the first pressure gauge 301 and the second pressure gauge 201 are read at an arbitrary time after the measured tare 100 is fully inflated, and the pressure values of the gas supply tank 300 and the measurement container 200 are read.
Measure P ₂ and P _B.

Based on these measured values P ₁ , P ₂ , P _A , P _B (absolute pressure), the internal volume V _{1 of the} gas supply source tank 300, and the internal volume V ₀ of the measuring container 200, the internal volume of the measured tare 100 is measured. x is Can be found at.

The reason will be described below.

In addition to the known values V ₁ , V ₀ and measured values P ₁ , P ₂ , P _A , P _B , the measured tare
The amount of gas leakage seen inside 100 is ΔV ₂ , the measured tare 100
Letting ΔV _B be the amount of gas leaked outside of, P ₂ ΔV ₂ = P _B ΔV _B ………… (2) P ₁ V ₁ = P ₂ (V ₁ + x + ΔV ₂ ) …… ( 3) P _A V ₀ + P _B ΔV _B = P _B (V ₀ −x) (4) Substituting equation (2), P _A V ₀ + P ₂ ΔV ₂ = P _B (V ₀ −x)… … (4) ′ From formula (3) ΔV ₂ = (P ₁ / P ₂ −1) V ₁ −x …… (3) ′ (3) ′ Formula is substituted into formula (4) ′ P _A V ₀ + P ₂ {(P ₁ / P ₂ -1) V ₁ −x} = P _B (V ₀ −x) (P ₁ -P ₂ ) V _1- (P _B -P _A ) V ₀ = (P ₂ -P _B ) x ………… (5) Equation (1) is derived from Equation (5).

Here, the inner volume V ₁ of the gas supply tank 300 and the measuring container 2
The internal volume V _{0 of} 00 must be several times larger than the internal volume x of the tare 100 to be measured. However, gas supply tank 30
When the initial pressure P _{1 of the} gas stored in 0 is large, the internal volume V ₁ can be reduced in inverse proportion to the pressure value P ₁ . In short, it suffices if a gas capable of sufficiently inflating the measured tare 100 is stored.

Further, the initial pressure P _A in the measurement container 200 is required to be sufficiently smaller than the initial pressure P ₁ of the gas supply 300.

From the above, it can be understood that the inner volume x of the tare 100 to be measured is obtained by the equation (1).

In the second invention of this application, since the inner volume x of the tare 100 to be measured is obtained, the leakage amount Δ is calculated from the above equation (3) ′.
V ₂ can be obtained. This leakage amount ΔV ₂ and the measured tare
The leak amount ΔV ₂ per unit time can be obtained by measuring the time t until 100 is fully expanded. As is clear from the equation (3) ′, the leakage amount ΔV ₂ is the tank 300
It is determined by the change ratio of the internal pressure and the internal volume x of the measured tare 100.

FIG. 3 shows a specific embodiment for constructing the device of this application.

In this embodiment, for one gas supply tank 300,
A plurality of (two in this example) measuring vessels 200A and 200B are connected through a valve 401 and a switching valve 402, and the measuring vessels 200A and 200B are alternately connected to the gas supply tank 300 by switching the switching valve 402. The structure is shown.

In this way, the measurement containers 200A and 200B are stored in the gas supply tank.
By being configured so that they can be alternately connected to 300, it is possible to perform the work of exchanging the tare 100 to be measured for the other measuring container 200B while the one measuring container 200A is performing the measurement. Therefore, one gas supply tank 300
Can be used for efficient measurement.

FIG. 4 shows a modified embodiment of the present invention. In this example, the gas pressure source 700 supplies gas pressure to the measuring container 200, which indicates that the pressure gauge 701 constantly indicates a constant pressure, through the integrating flow meter 600, and the integrating flow meter 600 measures the gas flow rate. Then
_A case is shown in which the internal volume x of the tare 100 to be measured is measured by the integrated flow rate value and the pressure change P _A -P _B in the measuring container 200.

Also in the embodiment shown in FIG. 4, the internal volume x of the measured tare 100 can be measured.

"Effects of the Invention" As described above, according to the present invention, it is possible to measure the internal volume of a tare with a leak. In particular, FIGS. 1 to 3
According to the embodiment described in the drawings, since the measured value is only the pressure value, the pressure can be easily measured with high accuracy, and therefore the measurement with high accuracy can be performed.

Therefore, for example, when it is used for measuring the inner volume of an automobile airbag, it greatly contributes to the reliability improvement of the airbag.

[Brief description of drawings]

1 and 2 are diagrams for explaining the first to third inventions of this application, and FIG. 3 is a diagram showing an example of a specific configuration of the device proposed in the third invention of this application, FIG. 4 is a diagram for explaining a modified embodiment of the present invention. 100: Tare to be measured, 200: Measuring container, 201: Pressure gauge, 300: Tank for gas supply source, 301: Pressure gauge, 400: Pipe, 401: Shut-off valve,
500: Gas source.

Claims (3)

[Claims] 1. _A known initial gas pressure P _A and a known internal volume V _0.
While placing the measured tare in a folded state in the measuring container equipped with, the measured tare has a gas pressure P ₁ larger than the gas pressure in the measuring container, and the internal volume V ₁ is known. A gas is supplied from a certain gas supply source, and the internal volume X of the tare to be measured is X = [from the pressure P _B in the measuring container at the time when the tare to be measured is sufficiently inflated and the pressure P ₂ of the gas supply source. (P ₁ -P ₂ ) V _1- (P _B -P _A ) V _O ] / (P ₂ -P _B ). 2. Leakage for calculating the amount of gas leaked from the measured tare from the internal volume value of the measured tare measured by the internal volume measuring method according to claim 1 and the pressure change of the atmospheric pressure supply source. A method for measuring the amount of tare leakage. 3. A tank for a gas supply source capable of supplying a gas having a volume larger than the inner volume of the tare to be measured to the tare to be measured, and B. A first pressure measuring tank for the gas supply source. A pressure gauge, C. a gas source that supplies gas to the gas source tank before the start of measurement to increase the gas pressure in the gas source tank to a desired value, and D. the above gas source and gas supply during measurement. A shut-off valve for shutting off between the source tank, E. a measuring container having a known internal volume larger than the internal volume of the tare to be measured, F. this measuring container and the gas supply tank G. a pipe that communicates with G. a coupling that is attached to the mouth of the pipe formed on the inner wall of this measuring container and that attaches and detaches the gas inlet of the tare to be measured to the mouth of this pipe. Second pressure gauge for measuring the pressure in the container for the gas supply, and I. The tank for the gas supply source provided in the above pipe and only for the time of measurement Leakage tare of the internal volume measuring device with a configured by a valve switching a state for supplying the gas, to be measured tare mounted on Luo the connector.