JP2005300338A - Automobile component inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately measure a volume of an automobile component of a complicated shape that is a measuring object, while keeping a clean condition. <P>SOLUTION: Propane gas of a fixed concentration of is introduced into an empty measuring vessel 1 by a fixed amount from a propane gas introducing part 3 under the condition where atmospheric pressure of air is sealed, and a sample gas mixed sufficiently with the propane is GC-analyzed to find a peak area corresponding to a propane concentration C<SB>0</SB>. Then, the atmospheric pressure of air is sealed in the measuring vessel 1 by the same manner under the condition where the measuring object S is stored therein, and the propane is introduced and GC-analyzed to find a peak area corresponding to a propane concentration C<SB>R</SB>. The volume of the measuring object is calculated based on the concentrations C<SB>0</SB>, C<SB>R</SB>, and a content volume of the measuring vessel 1, since a space volume in an inside of the measuring vessel 1 is reduced by the storage of the measuring object S to increase the propane concentration by a volume corresponding thereto. In particular, an analytical time is shortened and inspection efficiency is enhanced by selecting the component such as propane, propylene, ethane and ethylene as an analyte. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an automobile part inspection apparatus, and more particularly to an automobile part inspection apparatus that measures the volume of various automobile parts having a complicated shape.

  The most common method for measuring the volume of an automobile part or the like is to perform theoretical calculation from dimensions based on the design drawing of the part. However, when the shape is complicated, there is a problem that accurate calculation is difficult. For example, in-vehicle air conditioners are composed of components such as compressors, evaporators, and capacitors, but all of these components have extremely complex shapes, and it is virtually impossible to determine their volume by theoretical calculation. is there. Even if the shape is simple, it is impossible to measure the actual volume although it is not as designed due to variations and defects in molding.

  As a method for actually measuring the volume of a molded product having such a complicated shape, a method using water (or other liquid) as described in Patent Document 1, for example, is conventionally known. In the method described in this document, the object to be measured is submerged in a water tank in which a predetermined amount of water is stored, the amount of increase in the water level at that time is measured, and the volume of the object to be measured is calculated from the amount of water level rise and the bottom area of the water tank. Is calculated.

  In such a method, if even the water level can be read accurately, the volume can be calculated fairly accurately. However, in the case of automobile parts, for example, there is a risk of damaging the parts or degrading performance by immersing in water. In particular, in-vehicle air conditioners may use paper-derived parts for filters and the like, and such parts cannot be immersed in water. It is also conceivable to use a liquid that does not cause damage or performance degradation in place of water. However, if the part shape is complicated, such liquid may remain without being completely discharged. For example, in the case of part inspection used for mass production, it adheres to the part after inspection. Time to wait until the liquid is completely volatilized must be secured, which causes a problem in inspection efficiency. Further, when immersed in water, a water pressure higher than the atmospheric pressure is applied depending on the depth of the water.

Japanese Patent Application Laid-Open No. 6-147952

  Therefore, in the development / research field or the manufacturing field of automobiles and automobile parts, the use of liquid parts such as water without using liquids such as water, and without contaminating or damaging the measurement object. There is a strong need for an apparatus that can accurately measure volume. In consideration of use especially at the manufacturing site, an apparatus is desired that can inspect in as short a time as possible and can directly input the automobile parts after the inspection is finished into the mass production line. Furthermore, since it is difficult to introduce a large number of devices if the cost of the device is high, it is also necessary to suppress the cost of the device as much as possible.

  The present invention has been made in view of these points, and a main object of the present invention is an automobile part that can accurately and efficiently measure the volume of an automobile part having a complicated shape while maintaining a clean state. It is to provide an inspection device.

The present invention made to solve the above problems is an automobile parts inspection apparatus for measuring the volume of automobile parts by gas chromatographic analysis,
a) a gas chromatograph analyzing means including a separation column and a detector for detecting a component separated by the column;
b) a sealable measurement container for containing the measurement object;
c) a specific gas introduction means for introducing a predetermined amount of a specific gas other than the carrier gas into the measurement container;
d) Sample gas introduction means for collecting a certain amount of gas in the measurement container and introducing the collected sample gas into the column with a carrier gas;
e) The specific gas is introduced into the measurement container by the specific gas introduction means in a state where the measurement container is empty and a measurement object is accommodated in the measurement container, and the specific gas diffuses The sample gas in the measurement container is sampled by the sample gas introducing means and introduced into the gas chromatograph analyzing means, and a peak corresponding to the specific gas is found in the chromatogram obtained by the gas chromatographic analyzing means and its concentration An analysis execution means for calculating an index value that reflects
f) Based on two index values respectively obtained by the analysis execution means in a state where the measurement container is empty and a state in which the measurement object is accommodated in the measurement container, and the internal volume of the measurement container Computing processing means for calculating the volume of the measurement object;
It is characterized by having.

  Specifically, for example, the index value may be a peak area corresponding to a specific gas on a chromatogram. In a state where the measurement object is accommodated in the measurement container having a certain internal volume, the volume of the empty space in the measurement container is smaller than the internal volume of the measurement container by the volume of the measurement object. Therefore, when a specific gas of the same amount and the same concentration is introduced into the measurement container and diffused in the internal space in the state where the measurement container is empty and the state where the measurement object is accommodated in the measurement container, The concentration of the specific gas in the internal space is higher in the latter (in the state in which the measurement object is accommodated) by the narrower spatial volume than in the former. That is, the difference in concentration between the two reflects the difference in space volume in the measurement container, that is, the volume of the measurement object. The arithmetic processing means calculates the volume of the measurement object by substituting two index values into a predetermined arithmetic expression based on such a principle and executing the calculation.

  The specific gas used here is naturally other than the carrier gas, but it is preferable that the specific gas is chemically stable and can be detected with high sensitivity by a detector. In order to shorten the length, it is desirable that the column should pass through the column as quickly as possible. Of course, it is also necessary not to damage the automobile part to be measured. As the gas suitable for such conditions, for example, propane, propylene, ethane, ethylene and the like are suitable. Even if ethane is not prepared with ethane gas, since ethane gas is mixed with propane gas as an impurity at a predetermined ratio in a generally available propane gas, this propane gas is introduced into a measuring vessel and ethane contained as an impurity is gas chromatographed. It is good also as an analysis object in a graph.

  In this way, by using any one of propane, propylene, ethane, or ethylene as an analysis target in the gas chromatograph, the time for one gas chromatograph analysis can be shortened, which is advantageous for increasing the inspection efficiency. By repeatedly analyzing the same sample gas, the concentration calculation accuracy can be increased and the volume accuracy can be increased.

  The specific gas should be a gas that does not exist in the measurement container before the gas is introduced into the measurement container. However, even if the gas is present in the measurement container, there is no problem in the measurement. . That is, if it is not guaranteed that the same gas does not exist in the measurement container before the specific gas is introduced into the measurement container, the sample gas in the measurement container is first introduced before the specific gas is introduced. Gas chromatographic analysis to determine the concentration of the specific gas or the above index value, and subsequently introduce the specific gas into the measurement container, and then perform the gas chromatographic analysis of the sample gas in the measurement container to determine the concentration of the specific gas or the above index By obtaining the value and calculating the difference between the two concentrations or the index value, the influence of the specific gas originally present in the measurement container can be excluded.

  In addition, normal air may be present in the measurement container that has been sealed before the specific gas is introduced, but the air in the measurement container may be another gas (for example, an inert gas such as nitrogen). May be substituted. Such replacement ensures that the specific gas does not exist in the measurement container before the introduction of the specific gas, so that it is not necessary to analyze the concentration of the specific gas existing in the measurement container in advance as described above. Become.

  According to the automobile parts inspection apparatus according to the present invention, even for parts having a very complicated shape, the parts can be maintained in a clean state without using a liquid such as water that may damage the parts. The volume can be obtained with high accuracy. Further, since a liquid such as water does not adhere to the parts after the measurement is completed, it can be put into the production line immediately after the measurement is completed. In addition, if a small amount of a specific gas is introduced into a measurement container that is sealed at approximately atmospheric pressure, the measurement container is approximately at atmospheric pressure, so that a large pressure is not applied to the object to be measured. Therefore, it is possible to accurately measure the volume even for parts that are recessed. Furthermore, the basic configuration of the apparatus according to the present invention is a gas chromatograph whose measurement target is a gas sample, and since it is relatively inexpensive among various types of analysis apparatuses, the cost of the apparatus can be kept low.

  Hereinafter, an automotive parts inspection apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a main part of an automobile parts inspection apparatus according to this embodiment.

  This inspection apparatus includes, as basic components, a measurement container 1 for accommodating a measurement object S that is an automobile part, and propane gas introduction for introducing propane gas, which is a specific gas in the present invention, into the measurement container 1. Unit 3, gas chromatograph unit 11 including column 12 and detector 13, sample gas introduction unit 4 that collects a certain amount of sample gas in the measurement container 1 and introduces it into the column 12, and detection signal from the detector 13 In response, the data processing unit 20 that executes data processing and a control unit 30 that comprehensively controls the operation of each unit are provided.

  The measuring container 1 having an internal volume V can be sealed so that gas does not enter and exit from the outside, and a fan 2 for stirring the gas sealed inside is attached. The internal volume of the measurement container 1 can be appropriately determined depending on the size of the measurement object S, but here it is assumed to be 30 L as an example. The internal volume V may be obtained from, for example, a dimension on the specification of the measurement container 1 or a dimension by actual measurement, but may be obtained by other methods.

The sample gas introduction unit 4 includes a sampling valve 5 that is a six-way valve that can be switched between a connection state indicated by a solid line and a connection state indicated by a dotted line in FIG. 1, a gas extraction port 1 a of the measurement container 1, and a sampling valve 5. Measurement with the electromagnetic on-off valve 6 connected between the port [3], the measuring tube 7 connected between the ports [5] and [6] of the sampling valve 5, and the port [4] of the sampling valve 5 A pump 8 connected between the gas recovery port 1b of the container 1 and a carrier gas supply port 10 connected to the port [2] of the sampling valve 5; the port [1] of the sampling valve 5 is a column 12 inlet ends are connected. The carrier gas is a mobile phase in the gas chromatograph unit 11, and generally helium (He) or nitrogen (N ₂ ), which is an inert gas, is used. The carrier gas supply port 10 has a pressure greater than atmospheric pressure, such as about atmospheric pressure, so that a certain amount of carrier gas flows in the column 12 due to the differential pressure between the carrier gas supply port 10 and the outlet end of the column 12. The carrier gas is supplied at twice the gas pressure.

  The propane gas introduction unit 3 has the same configuration as that of the sample gas introduction unit 4, for example, holds the propane gas in a pre-pressurized state in a predetermined capacity measuring tube, and receives a gas introduction instruction from the control unit 30. The propane gas held in the measuring tube can be configured to flow into the measurement container 1. Alternatively, a configuration may be adopted in which propane gas sucked into a fixed volume syringe or the like is injected into the measurement container 1 in response to a gas introduction instruction from the control unit 30. In any case, it is only necessary that the propane gas having a constant amount (for example, 1 to 10 mL) and a constant concentration can be stably introduced into the measurement container 1.

  The data processing unit 20 is embodied by a data processing device dedicated to a chromatograph (for example, Chromatopack (registered trademark) manufactured by Shimadzu Corporation or a personal computer). Functionally, the data processing unit 20 includes a chromatogram creation unit 21, a target peak area calculation unit 22, It includes a storage unit 23, a volume calculation unit 24, etc. The control unit 30 is also embodied by a personal computer or the like, and is provided with an operation unit 31 and a display unit 32.

Next, the basic principle of volume measurement of automobile parts in the apparatus of this embodiment will be described.
First, as an initial state, let us consider a state in which normal air is enclosed in a measurement container 1 having an internal volume V as shown in FIG. 2A and the gas pressure is atmospheric pressure. At this time, there is a possibility that a small amount of propane gas is contained in the air in the measurement container 1, but here, it is assumed that there is no propane gas contained initially for the sake of simplicity. A certain amount of propane gas having a constant concentration is introduced into the measurement container 1. As shown in FIG. 2B, the introduced propane gas is uniformly diffused into the space in the measurement container 1, and at this time, the concentration of propane in the sample gas in the measurement container 1 is C ₀ . And

Next, the measurement object S is accommodated in the measurement container 1 in a state where the propane gas is completely discharged from the measurement container 1, and normal air is sealed in the measurement container 1 in this state, and the gas pressure is atmospheric pressure. Is considered (FIG. 2 (c)). Also at this time, it is assumed that the propane gas is not contained in the air in the measurement container 1. If the volume of the measuring object S is V1, the volume of the space in the measurement container 1 should be (V-V1). A certain amount of propane gas having a constant concentration is introduced into the measurement container 1 in the same manner as described above. As shown in FIG. 2 (d), as introduced propane gas is uniformly diffused in the space in the measuring container 1, the concentration of propane in the sample gas measurement container 1 in this case is C _R And

Comparing the state of FIG. 2 (b) with the state of FIG. 2 (d), the latter itself has a narrower space in which the propane gas molecules spread than the former, despite the introduction of the same amount (number of molecules) of propane gas. Therefore, it is considered that the existence density of propane gas molecules is high and the propane concentration in the sample gas is increased accordingly. Therefore, since the propane gas is the same amount in both cases, the following equation is established.
V · C ₀ = (V−V1) · C _R
from now on,
V1 = V · (C _R −C ₀ ) / C _R (1)
It is obtained. That is, the propane concentration C _0, C _R and the measuring container 1 internal volume V of the sample gas in the measurement container 1 in each condition of FIG. 2 (b) and (d), the volume V1 of the measuring object S It is possible to calculate. Therefore, if the above equation (1) is given to the volume calculation unit 24 in advance, the volume V1 can be calculated by substituting the propane concentration C ₀ , _CR or an index value corresponding to this into the equation (1). it can.

  2A and 2C, it is assumed that propane gas does not exist in the measurement container 1, but this assumption cannot be adopted depending on the measurement environment conditions and the type of specific gas. In that case, the propane obtained by measuring the initial concentration of propane in the measurement container 1 in the states of FIGS. 2 (a) and 2 (c), and measuring in the states of FIGS. 2 (b) and (d), respectively. By subtracting the initial concentration from the concentration, the propane concentration derived from the propane gas introduced into the measurement container 1 later can be accurately obtained. As will be described later, in principle, in order to measure a certain propane concentration, it is only necessary to execute one gas chromatographic analysis. The propane concentration corresponding to each state of d) can be calculated.

  Further, in view of the above measurement conditions, the concentration and amount of propane gas introduced into the measurement container 1 need to be the same when the measurement container 1 is empty and when the measurement object is accommodated. However, as is clear from the equation (1), the concentration is not particularly limited. That is, the concentration itself may be unknown as long as the identity of the concentration is guaranteed, for example, by collecting gas from the same gas cylinder.

  Next, the procedure and operation for measuring the volume of the automobile part performed under the control of the control unit 30 in the apparatus having the configuration shown in FIG. 1 will be specifically described.

  First, as the reference data, the propane concentration is measured in a state where the measurement object S is not accommodated in the measurement container 1. That is, the measurement container 1 is filled with normal air, and the measurement container 1 is sealed so that the gas pressure becomes atmospheric pressure. At this time, the electromagnetic switching valve 6 is closed. Then, the sampling valve 5 is set to a connection state indicated by a dotted line in FIG. 1, and the pump 8 is driven and the electromagnetic on-off valve 6 is opened. Then, as shown by a thick line in FIG. 3, the gas extraction port 1a of the measurement container 1, the electromagnetic opening / closing valve 6, the ports [3] and [6] of the sampling valve 5, the measuring pipe 7 and the port [5 of the sampling valve 5] ], [4] -pump 8-gas recovery port 1b of the measurement container 1 is formed as a loop-shaped flow path, and the sample gas in the measurement container 1 flows through this flow path. At that time, a fixed amount of sample gas determined by the internal volume is held in the measuring tube 7. Since the sample gas returns cyclically into the measurement container 1, the inside of the measurement container 1 is maintained at atmospheric pressure.

  After a predetermined time has elapsed, the sampling valve 5 is switched to a connection state indicated by a solid line in FIG. Then, as indicated by a thick line in FIG. 4, the carrier gas supply port 10 -ports [2] and [5] of the sampling valve 5 -the measuring pipe 7 -ports [6] and [1] of the sampling valve 5 The carrier gas flows through this flow path and enters the column 12. Since the sample gas is held in the measuring tube 7 immediately before the sampling valve 5 is switched, when the carrier gas flows into the measuring tube 7 after the sampling valve 5 is switched, the sample gas is pushed by the carrier gas and the carrier gas. At the same time, it is introduced into the column 12. Various components included in the sample gas are separated in the time direction while the sample gas passes through the column 12, and are sequentially output from the outlet of the column 12 and detected by the detector 13.

In the data processing unit 20, a chromatogram creation unit 21 creates a chromatogram based on a detection signal input with the passage of time. Since the retention time at which the peak corresponding to propane (C ₃ H ₈ ) appears on this chromatogram is known, the target peak area calculation unit 22 detects the peak corresponding to propane based on this known retention time, The peak area is calculated as an index value corresponding to the concentration. A well-known method can be used as a method for calculating the peak area. In general, since the air in the measurement container 1 does not contain propane having a detectable concentration, no peak corresponding to propane appears in such a case. Here, when the area of the peak with respect to propane is obtained, the value is stored in the storage unit 23. When no peak is found, zero is stored as the peak area. The value of the peak area at this time is an index value corresponding to the propane concentration in the state of FIG.

Next, the sampling valve 5 is switched again to the connection state indicated by the solid line in FIG. 1, the pump 8 is stopped, and the electromagnetic on-off valve 6 is closed. Then, a fixed amount of propane gas is introduced from the propane gas introduction unit 3 into the measurement container 1 in a state where the air is sealed, and then the fan 2 is operated for a predetermined time, so that it is introduced first. Stir the propane gas so that it is evenly mixed with the air. Thereafter, a sample gas is collected in the measuring tube 7 in the same procedure as described above, and the sample gas is placed on the carrier gas flow and introduced into the column 12 to perform gas chromatographic analysis. At this time, the chromatogram creation unit 21 creates a chromatogram as shown in FIG. That is, since propane (C ₃ H ₈ ) passes through the column 12 in a relatively short time and a chromatogram after the peak corresponding to propane appears (for example, C _{4 and} thereafter in FIG. 5) is unnecessary. In particular, the time for gas chromatogram analysis is considerably short.

When propane gas is introduced into the measurement container 1, the peak corresponding to propane appears very clearly, so the target peak area calculation unit 22 detects the peak corresponding to propane and calculates the peak area. The value of the peak area at this time is an index value corresponding to the propane concentration in the state of FIG. Then, by subtracting the peak area before the introduction of propane gas previously stored in the storage unit 23 from the peak area calculated here, the influence of the propane gas originally left in the measurement container 1 is removed and introduced. The peak area derived from the produced propane gas is obtained. This is newly stored in the storage unit 23. The value stored here is an index value corresponding to the propane concentration C ₀ in the equation (1).

Next, the measurement container 1 is sealed in a state where the measurement object S is accommodated in the measurement container 1, and the peak area of propane in a state before introducing propane gas into the measurement container 1 in the same procedure as described above The propane peak area after the introduction of propane gas into the measuring vessel 1 and stirring is obtained, and the difference is removed to eliminate the influence of the propane gas originally remaining in the measuring vessel 1 The peak area derived from propane gas is obtained. Here value calculated by the (1) is an index value corresponding to the propane concentration C _R in the formula. Since the peak area is a value proportional to the constituent concentration can be substituted directly in place of the propane concentration C _0, C _R in formula (1). Therefore, the volume calculation unit 24 performs such calculation to calculate the volume V1 of the measurement object S and displays the value on the display unit 32 via the control unit 30.

Here is an example of the calculation. As described above, the measurement container 1 has an internal volume of 30 [L], and the peak area corresponding to the concentration C ₀ of propane in the state where the measurement container 1 is empty is 50,000 counts. It is assumed that the peak area corresponding to the concentration C _R of propane in a state where S is accommodated is obtained as 60,000 counts. (1)
_{V1 = V · (C R -C} 0) / C R
= 30 ・ (60,000-50,000) / 60,000 = 5 [L]
It is obtained. That is, the volume of the measuring object S is 5 [L].

  The above-described embodiment is an example of the present invention, and modifications, corrections, and additions may be made as appropriate within the scope of the present invention. For example, as clearly shown in FIG. 5, the peak due to components such as propylene, ethane, and ethylene appears on the chromatogram so as to be separable from the peaks due to air and methane at the same time or earlier than propane. Ingredients may be used in place of propane. Moreover, the structure of the sample gas introduction part in the said Example can be changed suitably. In the above embodiment, the gas chromatograph analysis is performed only once in each state. However, the gas chromatograph analysis is repeatedly performed on the same state several times to obtain the respective peak areas, and the average of the peak areas is calculated. By doing so, you may make it reduce the error by the dispersion | variation in peak area measurement. In particular, in the configuration of the above embodiment, the loop-shaped flow path is formed so that the sample gas sucked from the measurement container 1 is returned to the measurement container 1 again, which is suitable for repeated measurement of the same sample gas. Yes.

The block diagram of the principal part of the automotive component inspection apparatus by one Example of this invention. The schematic diagram for demonstrating the basic principle of the volume measurement of the measuring object in the automotive component inspection apparatus of a present Example. The flow-path block diagram of the principal part for demonstrating the operation | movement at the time of a measurement. The flow-path block diagram of the principal part for demonstrating the operation | movement at the time of a measurement. The figure which shows an example of the chromatogram obtained with the apparatus of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Measurement container 1a ... Gas extraction port 1b ... Gas recovery port 2 ... Fan 3 ... Propane gas introduction part 4 ... Sample gas introduction part 5 ... Sampling valve 6 ... Electromagnetic switching valve 7 ... Metering pipe 8 ... Pump 10 ... Carrier gas Supply port 11 ... gas chromatograph part 12 ... column 13 ... detector 20 ... data processing part 21 ... chromatogram creation part 22 ... target peak area calculation part 23 ... storage part 24 ... volume calculation part 30 ... control part 31 ... operation part 32 ... Display S ... Measurement object

Claims (2)

An automobile parts inspection device for measuring the volume of automobile parts by gas chromatographic analysis,
a) a gas chromatograph analyzing means including a separation column and a detector for detecting a component separated by the column;
b) a sealable measurement container for containing the measurement object;
c) a specific gas introduction means for introducing a predetermined amount of a specific gas other than the carrier gas into the measurement container;
d) Sample gas introduction means for collecting a certain amount of gas in the measurement container and introducing the collected sample gas into the column by a carrier gas;
e) The specific gas is introduced into the measurement container by the specific gas introduction means in a state where the measurement container is empty and a measurement object is accommodated in the measurement container, and the specific gas diffuses The sample gas in the measurement container is sampled by the sample gas introducing means and introduced into the gas chromatograph analyzing means, and a peak corresponding to the specific gas is found in the chromatogram obtained by the gas chromatographic analyzing means and its concentration An analysis execution means for calculating an index value that reflects
f) Based on two index values respectively obtained by the analysis execution means in a state where the measurement container is empty and a state in which the measurement object is accommodated in the measurement container, and the internal volume of the measurement container Computing processing means for calculating the volume of the measurement object;
An automobile parts inspection apparatus comprising: 2. The automobile part inspection apparatus according to claim 1, wherein the specific gas is propane, propylene, ethane, or ethylene.

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