JP4438607B2 - Method and apparatus for blockage inspection of flow path - Google Patents

Description

  The present invention relates to a flow path blockage inspection method and apparatus for inspecting a flow path block formed in a workpiece.

  For example, cylinder heads, gear carriers, and the like, which are cast products for automobiles, have a hollow shape inside. In forming this hollow shape, a core formed by a shell mold method or a cold box method is generally used. The core may be broken or cracked during conveyance or casting. When casting is performed using a core that has been broken or the like, burrs are formed in the flow path to be formed by the core, and the flow path is blocked. In the present specification, the term “blocking” includes both a state where the flow path section is completely blocked and a state where a part of the flow path section is blocked and the flow path is narrowed.

Before the cast molded product is shipped as a product, the presence or absence of blockage of the flow path is inspected. The blockage inspection method for the flow path is based on the difference between the fluid pressure supplied to the flow path and the fluid pressure discharged from the flow path, as shown in Patent Document 1, in addition to visual inspection and sensory inspection using a fiberscope. Thus, there is a method for detecting a blockage in the flow path. In the inspection method of Patent Document 1, a fluid supply pipe is connected to an inlet portion of a flow path via a sealing material, and a fluid discharge pipe is connected to an outlet portion of the flow path via a sealing material.
Japanese Patent Laid-Open No. 06-249727

  The inspection method of Patent Document 1 can be easily applied to a cast product having a shape in which an inlet portion and an outlet portion of a flow channel face the outside.

  However, some of the cast molded products have a shape in which a hollow portion having both ends opened and a flow path that is open with both ends facing the hollow portion and is subject to blockage inspection are formed. If the blockage of this flow path is to be inspected by the method of Patent Document 1, the fluid supply pipe must be connected to one opening and the fluid discharge pipe must be connected to the other opening inside the hollow portion. For this reason, when the cross section of the hollow portion is relatively small, or when a convex portion exists in the vicinity of the opening, the fluid supply pipe or the like cannot be connected to the opening, and the flow path is blocked. Cannot inspect.

  An object of the present invention is to easily inspect the blockage of a flow path for a workpiece formed with a hollow part having both ends opened and a flow path that is open with both ends facing the hollow part and is subject to blockage inspection. It is an object of the present invention to provide a flow path blockage inspection method and apparatus therefor.

  The above object is achieved by the following means.

(1) For a workpiece in which a hollow part having both ends opened and a flow path that is open with both ends facing the hollow part and is a target for blockage inspection, And forming a back pressure chamber in the hollow portion having an inner volume larger than the inner volume of the flow path,
Through the adjusting means for adjusting the gas flow rate to a constant flow rate, a constant flow rate gas is supplied into the back pressure chamber,
This is a flow path blockage inspection method in which blockage in the flow path is detected based on a gas back pressure during gas supply.

(2) For a workpiece in which a hollow part having both ends opened and a flow path that is open with both ends facing the hollow part and is subject to blockage inspection, only one opening in the flow path is included. And a pair of sealing means for partitioning and forming a back pressure chamber having an internal volume larger than the internal volume of the flow path in the hollow portion;
Adjusting means for adjusting the gas flow rate to a constant flow rate;
Back pressure detection means for detecting a back pressure of the gas when supplying a constant flow of gas into the back pressure chamber via the adjusting means;
And a control means for detecting a blockage in the flow path based on the back pressure of the gas detected by the back pressure detection means.

  According to the present invention, since the gas is once supplied into the back pressure chamber having an internal volume larger than the internal volume of the flow path, the pressure of the gas flowing into the flow path can be stabilized. Furthermore, since a constant flow of gas is continuously supplied into the back pressure chamber, it is possible to detect a rise in back pressure due to the blockage of the flow path with high sensitivity, and as a result, a non-defective product / defective product is determined. Accuracy can be increased.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing a flow path blockage inspection apparatus 10 that embodies the flow path blockage inspection method according to the present invention, and FIG. 2 is a system configuration diagram of the inspection apparatus.

  Referring to FIGS. 1 and 2, a flow path blockage inspection apparatus 10 includes a hollow portion 21 having both ends opened, and a flow path 22 having both ends opened toward the hollow portion 21 and subject to blockage inspection. It is used to detect blockage in the flow path 22 with respect to the formed work 20. Briefly, the flow path blockage inspection apparatus 10 includes only one opening 22a in the flow path 22 of the workpiece 20 and hollows the back pressure chamber 30 having an internal volume larger than the internal volume of the flow path 22. A pair of sealing means 31 and 32 that are partitioned in the portion 21, an adjustment means 40 that adjusts the gas flow rate to a constant flow rate, and a gas at a constant flow rate is supplied into the back pressure chamber 30 via the adjustment means 40. On the basis of the back pressure sensor 50 (corresponding to the back pressure detecting means 50) for detecting the back pressure of the gas when the gas is flowing and the back pressure of the gas detected by the back pressure sensor 50, the blockage in the flow path 22 is detected. And a controller 60 (corresponding to the control means 60).

  Furthermore, the flow path blockage inspection apparatus 10 includes a moving means 70 for moving one of the pair of sealing means 31 and 32, a fixing means 80 for fixing the other of the pair of sealing means 31 and 32, and a workpiece. 20, and a holding means 90 that is slidable along the direction in which one sealing means 32 moves relative to the other sealing means 31, and a movement control means that controls the operation of the moving means 70. Have. The movement control unit controls the operation of the moving unit 70 to slide the holding unit 90 while pressing the one sealing unit 32 against the workpiece 20, and presses the workpiece 20 against the other sealing unit 31. Details will be described below.

  Referring to FIG. 2, the workpiece 20 is a cast product in which the flow path 22 is formed using a core. The cast product shown in the figure is a gear carrier, and the flow path 22 is an oil passage. The hole diameter of the oil passage is about φ7 mm to φ8 mm. One opening 22a in the flow path 22 is opened facing the hollow portion 21 between the upper opening portion 21a of the hollow portion 21 in the drawing and the substantially intermediate portion 21c. The other opening 22b in the flow path 22 is opened facing the hollow portion 21 between the substantially intermediate portion 21c and the lower opening portion 21b of the hollow portion 21 in the drawing. For convenience of explanation, one opening 22a in the flow path 22 is referred to as a “first opening 22a”, and the other opening 22b is referred to as a “second opening 22b”.

  The pair of sealing means 31, 32 includes a first sealing means 31 that closes the upper opening 21 a of the hollow portion 21 and a second sealing means 32 that closes the substantially intermediate portion 21 c of the hollow portion 21. The second sealing means 32 is inserted from the lower opening 21 b of the hollow portion 21. The first sealing means 31 includes a sealing material 31a that contacts the upper opening 21a, and the second sealing means 32 includes a sealing material 32a that contacts the opening edge of the substantially intermediate portion 21c. Each of the sealing materials 31a and 32a has a shape that matches the sealing surface, and is made of, for example, silicon rubber. In order to bring each sealing material 31a closer to the sealing surface of the workpiece 20, a mold having the shape of the sealing surface of the workpiece 20 is used, and a sealing material 31a formed by pouring a liquid sealing material 31a into the mold is used. May be.

  A space including only the first opening 22 a in the flow path 22 is defined in the hollow portion 21 by closing the upper opening 21 a by the first sealing means 31 and closing the substantially intermediate portion 21 c by the second sealing means 32. It is formed. The sealing position by the first sealing means 31 and the second sealing means 32 defines a space including only the first opening 22 a in the flow path 22, and the partitioned space is larger than the internal volume of the flow path 22. A position having an internal volume is set. The gas supplied to the space flows into the flow path 22 through the first opening 22a, flows down the flow path 22, and is ejected from the second opening 22b. Therefore, the space constitutes a back pressure chamber 30 for the flow path 22. In addition, the convex-shaped part 23 exists in the inner surface of the hollow part 21 adjacent to the other opening part 22b. The convex portion 23 has a shape that does not hinder the forward / backward movement of the second seal means 32 but hinders the connection of the pipe to the other opening 22b.

  The first sealing means 31 is provided with a pipe 42 therethrough for supplying gas to the back pressure chamber 30. In order to stabilize the pressure in the back pressure chamber 30, the pipe 42 having a cross-sectional area larger than that of the flow path 22 is used. An adjusting means 40 capable of adjusting the gas flow rate to a constant flow rate is provided in the middle of the pipe 42.

  The adjusting means 40 includes, for example, a sonic nozzle 41 that can supply a constant flow rate gas regardless of the downstream pressure by keeping the upstream pressure constant. Since the sonic nozzle 41 is a known element that is also used for calibration of the flow rate, a detailed description is omitted. By using the sonic nozzle 41, the gas flow rate can be appropriately and easily controlled to a target value corresponding to the gas pressure supplied to the upstream side of the sonic nozzle 41.

  On the upstream side of the sonic nozzle 41, a regulator 44 into which the gas from the gas supply source 43 is introduced, a pressure sensor 45 for detecting the gas pressure supplied to the upstream side of the sonic nozzle 41, and the regulator 44. And a pressure control unit 46 for controlling the operation of. The pressure control unit 46 controls the operation of the regulator 44 based on the gas pressure detected by the pressure sensor 45. Accordingly, the gas pressure supplied to the upstream side of the sonic nozzle 41 is controlled to a constant pressure, and the gas flow rate is appropriately controlled to a target value corresponding to the gas pressure by the action of the sonic nozzle 41. As the gas, high-pressure air supplied to various places in the factory can be used.

  The back pressure sensor 50 is composed of a pressure sensor, and is provided in the middle of the pipe 42 in the illustrated example. As described above, since the cross-sectional area of the pipe 42 is larger than the cross-sectional area of the flow path 22, stabilization of the pressure in the back pressure chamber 30 is not hindered. Therefore, the back pressure sensor 50 can accurately detect the back pressure of the gas when supplying a constant flow rate of gas into the back pressure chamber 30 via the sonic nozzle 41.

  The controller 60 is mainly composed of a CPU, a memory and the like. If the flow path 22 to be inspected is blocked, it becomes a resistance when the gas flows, so that the back pressure of the gas detected by the back pressure sensor 50 becomes high. Thereby, the obstruction | occlusion in the flow path 22 is detectable. Specifically, the back pressure at a certain gas flow rate is measured in advance for a non-defective product in which the flow path 22 is not blocked and a defective product in which the flow path 22 is blocked. A threshold has been determined. Then, by comparing the back pressure of the gas detected by the back pressure sensor 50 with the threshold value with respect to the manufactured work 20, the blockage state in the flow path 22 is detected, and the pass / fail of the work 20 is detected. Is automatically determined. The memory of the controller 60 includes a correlation between the gas flow rate and the back pressure in the case of a non-defective product, a threshold value determined for each gas flow rate, a determination program, and a control program for controlling the operation of the entire blockage inspection apparatus 10. It is remembered.

  With reference to FIG. 1, a mechanism for partitioning and forming the back pressure chamber 30 by a pair of sealing means 31 and 32 will be described.

  In the flow path blockage inspection apparatus 10, a cylinder 70 (corresponding to the moving means 70) for moving the second sealing means 32 (corresponding to one sealing means 32) is placed on the base 11 via the support base 71. A support plate 80 (corresponding to the fixing means 80) for fixing and fixing the first sealing means 31 (corresponding to the other sealing means 31) is attached on the base 11. The cylinder 70 is composed of, for example, a fluid pressure cylinder that operates by hydraulic pressure or pneumatic pressure. The second sealing means 32 is attached to the tip of a rod 72 that moves forward and backward. The first sealing means 31 is attached to the support plate 80 so as to face the cylinder 70.

  A holding jig 90 (corresponding to the holding means 90) that holds the workpiece 20 is disposed on the base 11 between the cylinder 70 and the support plate 80. The workpiece 20 is held on the holding jig 90 with the upper opening 21 a of the hollow portion 21 facing the first sealing means 31 and the lower opening 21 b facing the second sealing means 32. The holding jig 90 includes a leg-shaped holding portion 91 that receives a locate portion (an uneven portion, a hole, or the like) set on the workpiece 20 and holds the workpiece 20 in a positioned state. The cylinder 70 is adjusted to a position where the sealing material 32 a of the second sealing means 32 can be brought into contact with the opening edge of the substantially intermediate portion 21 c of the workpiece 20. The support plate 80 is adjusted to a position where the sealing material 31 a of the first sealing means 31 can be brought into contact with the upper opening 21 a of the workpiece 20.

  The holding jig 90 further includes a slide mechanism 92 at a lower portion thereof, and is configured to be slidable along a direction in which the second seal means 32 moves with respect to the first seal means 31 (left-right direction in FIG. 1). Yes. Between the holding jig 90 and the support base 71, a resilient means 93 that biases the holding jig 90 and a resilient force for returning the positioned and held work 20 to the initial position is attached to the holding jig 90. I have a hand. The elastic means 93 is composed of, for example, a tension coil spring. The initial positions of the holding jig 90 and the workpiece 20 are the backward limit positions farthest from the fixed first seal means 31 as indicated by broken lines.

  In the present embodiment, the controller 60 described above also functions as a movement control unit that controls the operation of the cylinder 70.

  Next, the operation will be described.

  Referring to FIG. 1, in the blockage inspection device 10 for the flow path, the rod 72 of the cylinder 70 is in the retreat limit position before the inspection is started. The holding jig 90 is in an initial position indicated by a broken line, when the elastic force of the elastic means 93 is urged. The workpiece 20 is a cast product in which the flow path 22 is formed using a core. The workpiece 20 is held on the holding jig 90 while being positioned by the holding portion 91. The workpiece 20 is in an initial position indicated by a broken line.

  Next, the controller 60 controls the operation of the cylinder 70 and moves the rod 72 forward. Along with the forward movement of the rod 72, the sealing material 32a of the second sealing means 32 comes into contact with the opening edge of the substantially intermediate portion 21c which is one sealing surface of the workpiece 20.

  When the rod 72 is further moved forward, the workpiece 20 against which the second seal means 32 is pressed receives a propulsive force from the rod 72. Thereby, both the holding jig 90 and the workpiece 20 slide and move from the initial position toward the first seal means 31 against the elastic force of the elastic means 93.

  When the rod 72 is further moved forward, the upper opening 21a which is the other sealing surface of the workpiece 20 is pressed against the sealing material 31a of the first sealing means 31 whose position is fixed. The controller 60 stops the operation of the cylinder 70 when the upper opening 21a and the sealing material 31a come into close contact with each other. As a result, the upper opening 21 a is blocked by the first sealing means 31, the substantially intermediate portion 21 c is blocked by the second sealing means 32, and only the first opening 22 a in the flow path 22 is in the hollow portion 21. And a back pressure chamber 30 having an internal volume larger than the internal volume of the flow path 22 is defined.

  Since the flow path blockage inspection apparatus 10 employs the slide mechanism 92, the sealing members 31a and 32a are not evenly contacted with each sealing surface from both sides of the workpiece 20 without complicating the apparatus. It can be pressed with great force.

  Next, referring to FIG. 2, the pressure control unit 46 controls the operation of the regulator 44 based on the gas pressure detected by the pressure sensor 45, and controls the gas pressure supplied to the upstream side of the sonic nozzle 41. Thus, a constant flow rate gas determined by the gas pressure is supplied from the sonic nozzle 41 through the pipe 42 into the back pressure chamber 30. The gas supplied to the back pressure chamber 30 flows into the flow path 22 through the first opening 22a, flows down the flow path 22, and is ejected from the second opening 22b.

  The back pressure sensor 50 detects the back pressure of gas when a constant flow rate of gas is supplied into the back pressure chamber 30 via the sonic nozzle 41. Then, the controller 60 compares the back pressure of the gas detected by the back pressure sensor 50 with a preset threshold value, detects a blockage state in the flow path 22, and passes / fails the workpiece 20. Determine. For example, if the flow path 22 is blocked, it becomes a resistance when the gas flows, so the back pressure of the gas detected by the back pressure sensor 50 immediately increases. If the controller 60 determines that the back pressure of the gas detected by the back pressure sensor 50 is greater than the threshold value, the controller 60 detects that the flow path 22 is blocked and determines that it is a defective product.

  After the determination, the controller 60 stops the gas supply, controls the operation of the cylinder 70, and moves the rod 72 backward to the backward limit position. As the rod 72 moves backward, the holding jig 90 and the workpiece 20 both slide to the initial position due to the elastic force of the elastic means 93 and return to the state before the inspection is started.

  In the above-described blockage inspection, since the gas is once supplied into the back pressure chamber 30 having an internal volume larger than the internal volume of the flow path 22, the pressure of the gas flowing into the flow path 22 is stable. Furthermore, since a constant flow of gas is continuously supplied into the back pressure chamber 30, it is possible to detect an increase in back pressure due to the blockage of the flow path 22 with high sensitivity. It is possible to improve the accuracy of determining.

  FIG. 3 is a graph showing the results of an experiment examining the influence of the back pressure chamber 30 on the non-defective / defective product determination accuracy.

  A gear carrier, which is a cast product, was used for the workpiece. In the gear carrier, an oil passage as a flow path 22 to be subjected to blockage inspection is formed using a core. A defective workpiece in which half of the cross-sectional area of the oil passage was closed and a non-defective workpiece with no blockage were prepared.

  In order to create a state where the internal volume of the back pressure chamber is small, the pipe 42 on the downstream side of the sonic nozzle 41 is directly connected to the first opening 22a in the flow path 22 and the first opening 22a from the sonic nozzle 41 is connected. The internal volume of the pipe 42 leading to is set smaller than the internal volume of the entire oil passage. A pipe having a pipe diameter (inner diameter) of 6 mm and a pipe of 8 mm were used.

  On the other hand, in order to create the back pressure chamber 30 having an internal volume larger than the internal volume of the oil passage, the above-described flow path blockage inspection device 10 is used, the upper seal 21a is closed by the first sealing means 31, and the second The substantially intermediate portion 21c was closed by the sealing means 32. A pipe 42 with a pipe diameter (inner diameter) of 12 mm was used for the pipe 42 extending from the sonic nozzle 41 to the first sealing means 31. This is to prevent the stabilization of the pressure in the back pressure chamber 30 by using the pipe 42 having a cross-sectional area larger than the cross-sectional area of the flow path 22.

  Back pressure while changing the air flow rate when φ6mm piping is connected to each non-defective / defective workpiece 20 when φ8mm piping is connected, or when the blockage inspection device 10 of the flow path is used. Was measured. The measurement results are shown in FIG.

  As shown in FIG. 3, when viewed at the same air flow rate, the smaller the pipe diameter and the smaller the internal volume of the back pressure chamber 30, the larger the back pressure. In any case, the difference between the back pressure of the non-defective product and the back pressure of the defective product increases as the flow rate increases.

  However, the difference between the back pressure of non-defective products and that of defective products is about 1% when φ6mm pipes are connected, and about 3% when φ8mm pipes are connected. Absent.

  On the other hand, if the seal method is changed using the blockage inspection device 10 for the flow path and the pipe diameter is set to φ12 mm, the difference between the back pressure of the non-defective product and the back pressure of the defective product can be increased to about 20%. It was. This is considered to be due to the increased sensitivity of the back pressure received from the closed portion in the oil passage because the back pressure chamber 30 has an internal volume sufficiently larger than the internal volume of the oil passage and the back pressure is reduced. It is done.

It is a schematic block diagram which shows the blockade inspection apparatus of the flow path which actualized the blockage inspection method of the flow path which concerns on this invention. It is a system configuration figure of the inspection device. It is a graph which shows the result of the experiment which investigates the influence which a back pressure chamber has on the determination accuracy of a good article / defective article.

Explanation of symbols

10 Channel blockage inspection device,
20 works,
21 hollow part,
22 The flow path that is the subject of the blockage inspection,
22a 1st opening part (one opening part),
22b second opening (the other opening),
30 Back pressure chamber,
31 1st sealing means (the other sealing means),
31a sealing material,
32 second sealing means (one sealing means),
32a sealing material,
31, 32 A pair of sealing means,
40 adjustment means,
41 Sonic nozzle (adjustment means),
42 piping,
44 regulator,
45 pressure sensor,
46 pressure control unit,
50 Back pressure sensor (back pressure detection means),
60 controller (control means, movement control means),
70 cylinder (moving means),
80 support plate (fixing means),
90 Holding jig (holding means).

Claims (5)

One opening in the flow path is formed by a pair of sealing means for a work in which a hollow part having both ends opened and a flow path that is open with both ends facing the hollow part and is subject to blockage inspection is formed. A back pressure chamber having an internal volume larger than the internal volume of the flow path and having a volume inside the hollow portion,
Through the adjusting means for adjusting the gas flow rate to a constant flow rate, a constant flow rate gas is supplied into the back pressure chamber,
A flow path blockage inspection method that detects blockage in the flow path based on a back pressure of gas during gas supply. For a workpiece in which a hollow part having both ends opened and a flow path that is open with both ends facing the hollow part and is subject to blockage inspection, the work flow includes only one opening in the flow path and the flow. A pair of sealing means for defining a back pressure chamber having an internal volume larger than the internal volume of the passage in the hollow portion;
Adjusting means for adjusting the gas flow rate to a constant flow rate;
Back pressure detection means for detecting a back pressure of the gas when supplying a constant flow of gas into the back pressure chamber via the adjusting means;
A flow path blockage inspection apparatus comprising: control means for detecting blockage in the flow path based on the back pressure of the gas detected by the back pressure detection means. Moving means for moving one of the pair of sealing means;
Fixing means for fixing the other of the pair of sealing means;
Holding means that holds the workpiece and is slidable in a direction in which the one sealing means moves relative to the other sealing means;
Movement control means for controlling the operation of the movement means,
The movement control means controls the operation of the moving means to slide the holding means while pressing the one sealing means against the work, and to press the work against the other sealing means. The channel blockage inspection device according to claim 2, wherein   3. The flow path according to claim 2, wherein the adjusting unit is configured by a sonic nozzle capable of supplying a constant flow rate gas regardless of the downstream pressure by making the upstream pressure constant. Occlusion inspection device.   3. The flow path blockage inspection apparatus according to claim 2, wherein the workpiece is a cast product in which the flow path is formed using a core.

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