JP3406872B2 - Inspection method and apparatus for defective molding hole of cast molding - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for inspecting a defective molding hole of a cast molded product for inspecting a non-linear flow path formed in the cast molded product for clogging or constriction. is there.

[0002]

2. Description of the Related Art Flow passages for passing cooling water are complicatedly arranged inside a cast molded article such as a cylinder block or a cylinder head of an automobile. This flow path is obtained by placing the core in the mold, but when the core is broken or collapsed due to heat or molten metal flow during casting and the flow path is clogged or narrowed, cooling water is generated. Since there is a possibility that the flow will stop or the flow will become poor and cause cooling failure, which may cause engine failure such as overheating, all the products had to be inspected for all the channels after casting. Moreover,
A complicated flow path such as a flow path formed so as to surround a cylinder or a plug hole or having a step formed in the middle thereof is likely to be clogged or narrowed due to defective molding. But,
In the case of a complicatedly winding flow path, it is necessary to manually judge the quality of the flow path through a wire etc., or to judge the quality by observing the reflected light passing through by irradiating light from the opening at the beginning of the flow path. However, it is extremely difficult to pass the wire through the complicated and tortuous channel, and since the inner surface of the channel is rough due to the molding sand, almost no light is reflected in the tortuous channel. The light did not reach the terminal opening, and it was extremely difficult to measure the inside of the flow path. In addition, a method of investigating by flowing water into the flow channel is conceivable. If the flow channel is branched in the middle, measurement is impossible. Therefore, a device may be considered in which air is supplied from the start end opening into the flow passage and the air pressure and the air flow rate at the end opening are detected by a sensor, but it is impossible to supply the air pressure only to the flow passage to be inspected. Moreover, since the flow path is not so long, the pressure difference between both ends cannot be large, so that a huge amount of air is required. Moreover, since the air pressure and the air flow rate also leak from the other flow paths, the air flow is attenuated to 1/1000 or less at the branch point and the quality cannot be judged.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for inspecting a defective molding hole of a cast molded product, which can inspect the degree of blockage in a complicated flow path. .

[0004]

In order to achieve the above-mentioned object, the present invention is directed to a cross-section of a basin which is approximately equal to the cross-sectional area of the flow path toward the starting end opening of the non-linear flow path formed inside the casting. Air with a constant pressure is blown, and the air flowing out from the end opening of the flow path is inserted between the end opening and the wind speed sensor.
A method for inspecting a defective molding hole of a cast molded product, which is stabilized by a space formed and measured by a wind speed sensor, is defined as the invention of claim 1, and in the invention of claim 1, the air blown back from the starting end opening is dissipated to the outside. The method for inspecting a defective molding hole of a cast molded product according to the present invention is defined as the invention of claim 2, and the blown into one or a plurality of starting end openings of one or a plurality of non-linear flow paths formed inside the cast molded product. The control means for controlling the constant pressure air to have a basin cross section substantially equal to the cross-sectional area of the flow passage, and stabilizing the air flowing out from the one or more terminal openings of the one or more non-linear flow passages. 4. A molding defect hole inspection device for a cast product, comprising: a buffer means; and an air velocity sensor for measuring an air flow rate through the buffer means.
In the invention of claim 3, the control means is based on the nozzle diameter set according to the distance from the air nozzle to the starting end opening. A fifth aspect of the present invention is an apparatus for inspecting a defective molding hole in a cast product, wherein the means is a space formed between the terminal opening and the wind velocity sensor.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a preferred embodiment of the present invention for inspecting a flow path of a cylinder head will be described with reference to FIGS.
It will be described in detail based on Nos. 4 and 5. Reference numeral 1 is a measuring instrument that is positioned and fixed to the cylinder head H.
Is composed of an air flow control means 2, an air circuit 3 and an anemometer 5. The control means 2 is for making a constant-pressure air flow supplied from the air circuit 3 into a flow area cross section that is substantially equal to the cross-sectional area of the starting end opening J of the flow path R to be inspected. The cross section of the basin is determined by the distance from to the starting end opening J of the flow path R. Further, the flow path R to be inspected is preferably a continuous one without lateral holes in terms of measurement accuracy, but the lateral hole cannot be avoided in measurement, and the lateral hole reduces the inspection accuracy so that it cannot be ignored. Or if the measurement becomes impossible,
The measurement is performed by closing the lateral hole. Further, the air nozzle 2a is inserted into the vertical hole S communicating with the flow path R, but it is assumed that a gap is formed between the inner diameter of the vertical hole S and the outer diameter of the air nozzle 2a. The air flow blown back from the opening cross section of J and the air flow blown back due to clogging or constriction of the flow path R can be quickly dissipated to the outside through the gap. This is because if the overflowed air is not dissipated to the outside as in the sample 3 shown in the graph of FIG.
This is to prevent the wind speed from being detected by flowing into the wind speed sensor 5a, even though the aperture ratio is 0%, or the wind speed measured by extra air to have an error. An air supply cylinder 3a supplies air to the air nozzle 2a.

As shown in FIG. 1, the air circuit 3 connected to the air supply cylinder 3a has a tank 10 for storing air obtained by a compressor or the like, a filter 11 for removing water in the air, and Pressure gauge 1 for adjusting pressure
A regulator 12 with 2a, an on-off valve 13 for turning air on and off, and a speed controller 14 for controlling the ejection amount of air, which is capable of constantly generating pulsation-free air having a constant pressure and supplying the air to the air supply cylinder 3a. I am trying. Therefore, in order to obtain a flow area cross section that is substantially equal to the cross-sectional area of the starting end opening J of the flow path R in the air flow, the distance from the air nozzle 2a to the starting end opening J is made constant, and the nozzle diameter of the air nozzle 2a having an arbitrary nozzle shape is set. It is only necessary to measure the cross section of the basin of the air generated when the air nozzles are sequentially changed, and set the air nozzle 2a to be used based on the measured value. Further, the shape of the nozzle hole is preferably a circular hole or a long hole matching the hole shape such as a non-circular hole or a long hole of the flow path R to be inspected, and it is preferable to reduce the air flow overflowing from the starting end opening J. A circular shape that covers the R hole shape may be used. Furthermore, the air nozzle 2a
When the nozzle hole is a vertically elongated hole, the cross-section of the air flow area expands slightly downward, so the blowback amount can be reduced by aligning the nozzle center slightly above the center of the starting end opening J of the vertically elongated hole. Becomes Also, since the nozzle hole portion of equal diameter of the air nozzle 2a has a smaller or larger spread angle of the air flow depending on the wall thickness,
By changing the variation in the distance from the air nozzle 2a to the starting end opening J by changing the wall thickness, it is possible to obtain a basin cross section that substantially matches the sectional area of the starting end opening J. That is, the air nozzle 2a
If the distance from the start end opening J is short, the wall thickness is thin,
When the distance from the air nozzle 2a to the starting end opening J is long, the wall thickness is made thicker, and when the wall thickness of the nozzle hole portion does not allow to obtain a basin cross section substantially equal to the starting end opening J,
The nozzle diameter may be changed to obtain a basin cross section that substantially matches the cross-sectional area of the starting end opening J. On the contrary, when the distance from the air nozzle 2a to the starting end opening J and the wall thickness are constant, the nozzle diameter may be changed to obtain a basin cross section that substantially matches the cross sectional area of the starting end opening J.

The anemometer 5 is composed of an anemometer 5a and a display portion 5d. The anemometer 5a is arranged in a vertical hole S on the side of the terminal opening K of the flow path R via a holder 20. When the sensor portion is a platinum resistance wire to which a weak current is applied, when the heat generating platinum resistance wire receives a flow of air and the temperature decreases, the wind speed is detected from the resistance change due to the temperature decrease. Further, the holder 20 for holding the wind speed sensor 5a is formed of a cylindrical body having a flanged plug body 20a which is fitted and locked at the rim of the vertical hole S, and the wind speed sensor 5a is provided in the center hole of the holder 20. Is fitted. 5c
Is a long window hole formed in the case 5b of the wind speed sensor 5a, and the upper end of the long window hole 5c is exposed to the outside from the holder 20 so that the air flow flowing into the case 5b does not generate back pressure. After passing through the sensor 5a, it is promptly discharged to the outside.

A buffer means 7 collects the air flow toward the wind speed sensor 5a and stabilizes (uniformizes) the flow speed of the air by stabilizing the flow speed of the air. The air is throttled by the turbulence, the turbulence occurs in the air flow, the air flow velocity and the direction of the flow change, and the air flow does not hit the wind speed sensor 5a, or a partial strong air flow hits the wind speed sensor 5a, The buffer means 7 prevents the accurate wind speed from becoming undetectable, and the buffer means 7 forms a space P formed between the terminal opening K and the vertical hole S.
I am trying. The role of the space P as the buffer means 7 is
This was investigated by a simulation experiment in which the presence or absence of a cylinder for guiding the air flow to the wind speed sensor 5a was replaced. In the tube according to this experiment, the air when the shield plate is displaced in the flow path is detected by the wind speed sensor 5a.
By leading to, the diffusion of the air flow is prevented and the flow velocity of the air is reduced to stabilize (uniformize). As a result, as shown in the graph of FIG. 5, the difference with the sample data (the value when the ideal wind speed is obtained) becomes large without the cylinder without the space P, while the space P
It was confirmed that it is extremely effective in the case of a cylinder with a, since it can be obtained from data that is close to the sample data.

The space P has a larger volume than the volume of the flow path R obtained by fitting the holder 20 into the vertical hole S with the flanged plug 20a, but the turbulent flow is terminated. The distance may be a uniform flow. Further, the space P may have a starting end opening J or the like connected to another flow path R, but in this case, the ratio of the air flow escaping from the starting end opening J and the air flow toward the wind speed sensor 5a is always constant. I want it. Reference numeral 21 denotes a temperature compensator. The temperature compensator 21 incorporates a thermistor or resistance wire for temperature detection, and is detected by utilizing the characteristics of the thermistor or resistance wire whose resistance value changes according to temperature. The detection value of the wind speed sensor 5a is corrected according to the temperature of the air flow to prevent the detection accuracy from decreasing due to the temperature difference.

With this construction, the cylinder head H is placed on the inspection table, and the control means 2 as the measuring instrument 1 is mounted on the cylinder head H as shown in FIG.
And the wind speed sensor 5a is positioned and fixed in each of the vertical holes S of the start and end openings J and K of the flow path R to be inspected. Then, FIG.
As shown in, the position adjustment is performed so that the air nozzle 2a accurately faces the starting end opening J of the flow path R. Then, by fitting the flanged plug body 20a of the holder 20 to the rim of the vertical hole S, the space P as the buffer means 7 for averaging the air flow flowing between the vertical hole S and the terminal opening K is provided. Form. In this way, the control means 2 and the wind speed sensor 5 of the anemometer 5
When a is positioned and arranged, and the on-off valve 13 of the air circuit 3 is opened, the air stored in the tank 10 has its moisture removed through the filter 11 and the regulator 1
The pressure is controlled to be constant by 2 and the air is ejected from the air nozzle 2a at a constant pressure without pulsation by controlling the air ejection amount by the speed controller 14 to be constant.

The constant-pressure air ejected from the air nozzle 2a has a basin cross-section that expands according to the nozzle diameter by the control means 2 having a nozzle diameter set according to the distance from the air nozzle 2a to the starting end opening J. Since it is set to be substantially equal to the cross-sectional area of the flow path R (cross-sectional area of the start-end opening) at the end of the start-end opening J, an air flow having a basin cross section substantially equal to the cross-sectional area of the flow path R is formed. It will be blown inside. At this time, a part of the air flow that exceeds the cross-sectional area of the starting end opening J is blown back and flows into the space P between the vertical hole S and the starting end opening J. The air flow that has flowed into this space P is a vertical hole. Since it will be dissipated to the outside through the gap between S and the air nozzle 2a, other lateral holes, etc., the amount of the overflowing air flow reaching the wind speed sensor 5a of the anemometer 5 is extremely small, and the measurement may be hindered. Absent.

Then, the air blown into the flow path R fully flows out from the terminal opening K through the arcuate path. At this time, if there is a molding defect such as a narrowed portion or a closed portion inside the flow channel R, the flow rate of the air flow having a flow region substantially equal to the cross-sectional area of the flow channel R will change. And the terminal opening K
The air flow that has flowed out of the cylinder collides with the cylindrical wall to become a downward flow, and the buffer means 7 formed between the vertical hole S and the terminal opening K is formed.
Will flow into the space P. When an airflow flows into this space P and a constriction as shown in FIG.
The amount of air blown from the air flow decreases, and at the same time, turbulence occurs, causing uneven velocity in the air flow, or even if the direction of the air flow deviates.
The flow velocity of the air flow is uniformized and stabilized, and the entire flow has a certain directionality. At this time, since the flow rate fluctuation of the air flow is not canceled by the stabilization of the air flow, the wind speed corresponding to the state of the flow path R is detected.

Then, the stable air flow, which has a uniform directionality while the flow velocity is averaged, is attached to the holder 20 fitted in the vertical hole S.
Through a long window hole 5c formed in the front portion of the case 5b.
Will be discharged to the outside through. In this manner, the air flow passing through the wind speed sensor 5a cools the platinum resistance wire that is being heated by being blown onto the sensor portion of the wind speed sensor 5a, and the wind speed is detected. If there is, the flow rate fluctuation is the wind speed and the wind speed sensor 5
The wind velocity is displayed on the display portion 5d of the anemometer 5 as detected by a. Further, since the temperature fluctuation of the air flow is detected by the thermistor or the resistance wire for temperature detection of the temperature compensator 21 whose resistance value changes according to the temperature, the current value detected by the wind speed sensor 5a according to the resistance value. Is compensated and the detected value does not fluctuate due to temperature, so the detected wind speed corresponds to the degree of constriction of the flow path R. For this reason,
If there is no clogging or constriction exceeding the allowable level in the arc-shaped flow path R, the wind speed exceeds the threshold value, and the flow path R is determined to be a good product with no abnormality, and as shown in FIG.
If there is a blockage or a stenosis exceeding the allowable level, the wind speed does not exceed the threshold value, so that the defective product is determined to be defective.

In the preferred embodiment, the control means 2 has a nozzle diameter corresponding to the distance from the air nozzle 2a to the starting end opening J. However, the control means 2 has the air nozzle 2a.
If a flexible hose or the like having an opening through which blowback air escapes is connected between the air nozzle 2 and the start end opening J, the air nozzle 2
It is not necessary to accurately set the distance from a to the starting end opening J or the nozzle diameter. In the preferred embodiment,
The buffer means 7 is a space P formed between the terminal opening K and the wind speed sensor 5a, but the buffer means 7 is a flexible hose having a volume larger than the volume of the flow path R connecting the terminal opening K and the wind speed sensor 5a. Of course, it is also good. Further, in the above-described preferred embodiment, the flow path of the cylinder head is inspected, but it can be used for inspecting a cylinder block and other cast molded articles having a flow path formed therein. Further, in the preferred embodiment, the flow paths R are inspected one by one, but the flow path R is inspected by arranging the control means 2 and each wind speed sensor 5a corresponding to a number of flow path R positions. The inspection time may be significantly shortened and the inspection efficiency may be improved by performing them at the same time. In this case, each wind speed sensor 5
It is preferable that the detection data of a is input to the determination circuit of the computer and automatically determined.

[0015]

As is apparent from the above description, the present invention allows the air flow to flow through the flow path by allowing air of a constant pressure having a flow area cross section substantially equal to the cross-sectional area of the starting end opening of the flow path to flow into the flow path. Since the flow will come into contact with the inner surface of the flow path, if there is constriction or clogging in the flow path, the air flow will be obstructed and the flow rate will fluctuate. It is possible to reliably detect defects. In addition, the air flow that has passed through the flow path is between the end opening and the wind speed sensor.
The unevenness of the velocity of the air flow due to the turbulent flow caused by the defective molding in the flow path and the deviation of the direction of the air flow are eliminated, and the air flow has a stable directionality. Since only the fluctuation of the flow rate is detected by the wind speed sensor, the detection accuracy can be improved. Moreover,
Compared to inspecting the inside of the flow path with flow rate and pressure, it is possible to reliably detect defective molding of the flow path with a small amount of air.
It is possible to reduce the power consumption by making the air generator small in size, and since high pressure air is not used, no intense noise is generated during inspection. Further, as in claim 2, the air blown back from the start end opening is dissipated to the outside, so that the air blown back is not detected by the wind velocity sensor, so that the measurement accuracy can be prevented from being lowered. . According to a fourth aspect of the present invention, the control means has a nozzle diameter set according to the distance from the air nozzle to the starting end opening, so that the cross section of the air flow is substantially equal to the sectional area of the starting end opening with a very simple and inexpensive structure. Can be obtained. When the buffer means is a space formed between the terminal opening and the wind speed sensor as in claim 5, the air flow can be stabilized and the measurement accuracy can be improved with a simple and inexpensive structure. It has various advantages. Therefore, the present invention is extremely significant in that it contributes to the development of the industry as a method and apparatus for inspecting a defective forming hole in a cast product that solves the conventional problems.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing a preferred embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a preferred embodiment of the present invention.

FIG. 3 is a partial transverse cross-sectional view showing a preferred embodiment of the present invention in which a flow path has a defective molding portion.

FIG. 4 is a sample data 1 in which an air flow is measured by a wind speed sensor in an ideal state, a sample data 2 is measured in a state in which an air flow is unevenly distributed, and air from the other hits the wind speed sensor. It is a graph which compares and shows the sample data 3 measured in the state.

FIG. 5 is a graph showing the wind speed when the shielding plate in the flow path is displaced, comparing the case where the wind speed sensor is guided with a cylinder and the case where the wind speed is measured without the cylinder.

[Explanation of symbols]

2 control means 2a air nozzle 5a Wind speed sensor 7 Buffer means J Start opening K terminal opening P space R flow path

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Claims (5)

(57) [Claims] 1. A constant pressure air having a basin cross-section substantially equal to the cross-sectional area of the flow path (R) toward the starting end opening (J) of the non-linear flow path (R) formed inside the cast molded product. with blowing and the air flowing out from the end opening (K) of the channel (R) terminating open
Inspection of poorly formed holes in cast products, characterized by being stabilized by the space (P) formed between the mouth (K) and the wind speed sensor (5a) and then measured by the wind speed sensor (5a) Method. 2. The method for inspecting a defective molding hole of a cast molded article according to claim 1, wherein the air blown back from the starting end opening (J) is dissipated to the outside. 3. One or more starting end openings of one or more non-linear flow paths (R) formed inside the casting.
A constant pressure air blown into (J), the control means (2) to make the flow area cross section approximately equal to the cross-sectional area of the flow path (R), and one or more non-linear flow path (R) One or more end openings
Buffer means (7) for stabilizing the air flowing out from (K),
A defective molding hole inspection device for a cast product, comprising: an air velocity sensor (5a) for measuring an air flow rate through the buffer means (7). 4. The defective molding hole inspection device for a cast product according to claim 3, wherein the control means (2) is based on a nozzle diameter set according to a distance from the air nozzle (2a) to the starting end opening (J). . 5. The defective molding hole inspection device for a cast product according to claim 3, wherein the buffer means (7) is a space (P) formed between the terminal opening (K) and the wind speed sensor (5a).