JP2007050492A - Hole surface machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hole surface machining method for efficiently applying surface machining to a hole formed in a workpiece. <P>SOLUTION: The method is used for machining the inside face 311 of a main hole 31 by jetting out a jet water flow 2 having prescribed water pressure to the inside of the main hole 31 bored in the workpiece 3. The jet water flow 2 is a two-layered jet water flow 2 composed of a high-pressure water flow 21 and a low-pressure water flow 22 surrounding the high-pressure water flow 21 and contains cavitation bubbles 23. A flow control jig 6 having a reflection face 61 for reflecting the high-pressure water flow 21 is arranged inside the main hole 31. A clearance between the flow control jig 6 and the inside face 311 of the main hole 31 is set to ≤400 μm. The jet water flow 2 hits the inside face 311 of the main hole 31 while the high-pressure water flow 21 is jetted out to the reflection face 61 so as to be reflected with the reflection face 61. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is directed to applying a high-pressure water stream containing cavitation bubbles to the inner surface of a hole provided in a workpiece such as a metal member, and applying a compressive stress to the hole surface of the workpiece, cleaning, etc. The present invention relates to a processing method.

  When applying compressive stress to a metal member, removing burrs from the processed part of the metal member, or cleaning dirt adhering to the surface of the metal member, a high-pressure water stream containing cavitation bubbles is applied to the surface of the metal member. There is a way to hit. That is, it is possible to perform processing such as applying a compressive stress to the surface of the metal member by a large impact pressure generated locally when the cavitation bubbles collapse on the surface of the metal member.

  As one of the surface processing methods for such metal members, a peening technique for pipe inner surface performed in water is disclosed (Patent Document 1). In this technique, a nozzle and a conical resistor are inserted into the inner surface of the tube in water, the conical resistor increases the pressure by reducing the flow path, and the generated cavitation bubbles are placed between the resistor and the inner surface of the tube. The peening is done by collapsing.

  However, in the above construction method, cavitation bubbles are generated in the liquid, and it is necessary to flow the flow accompanying the high-pressure water to the rear part of the cone resistor. That is, a sufficiently large clearance of, for example, 1.5 mm or more is required between the tube inner surface and the conical resistor. For this reason, cavitation flows from the clearance to the rear of the resistor, making it difficult to perform efficient peening.

Japanese Patent Laid-Open No. 10-76467

  The present invention has been made in view of such conventional problems, and intends to provide a hole surface processing method capable of efficiently performing surface processing on the inner surface of a hole provided in a workpiece. It is.

The present invention is a method of processing an inner surface of the hole by ejecting a jet water flow having a predetermined water pressure inside a hole drilled in a workpiece,
The jet stream is a two-layer jet stream composed of a high-pressure stream and a low-pressure stream surrounding the high-pressure stream, including cavitation bubbles,
A flow control jig having a reflective surface for reflecting the high-pressure water flow is disposed inside the hole,
The clearance between the flow control jig and the inner surface of the hole is 400 μm or less,
The hole surface processing method is characterized in that the jet water stream is applied to the inner surface of the hole by jetting the high-pressure water stream to the reflecting surface and reflecting it.

Next, the effects of the present invention will be described.
In the hole surface processing method, a jet water flow including cavitation bubbles generated by jetting a high-pressure water stream and jetting a low-pressure water stream so as to surround it is reflected on a reflection surface of the flow control jig. .

Then, by setting the clearance between the flow control jig and the inner surface of the hole of the workpiece to be 400 μm or less, it is possible to prevent cavitation bubbles from flowing out to the rear of the flow control jig. In addition, the cavitation bubbles can be efficiently collapsed by the rapid pressure increase of the jet water flow around the reflecting surface due to the reflection of the high-pressure water flow on the reflecting surface. At this time, an extremely large impact pressure is locally generated, and a sufficiently large compressive stress can be applied to the inner surface of the hole of the workpiece. That is, it is possible to efficiently apply a compressive stress to the inner surface of the hole.
Moreover, if the burr | flash has arisen on the hole surface, this burr | flash can be removed efficiently, and if dirt has adhered, this dirt can be wash | cleaned efficiently.

  As described above, according to the present invention, it is possible to provide a hole surface processing method that can efficiently perform a surface processing on the inner surface of a hole provided in a workpiece.

In the present invention (Claim 1), the workpiece is made of, for example, metal, resin, ceramic, or the like.
Moreover, the said hole surface processing method can be used, for example, when giving compressive stress (peening) to the inner surface of a hole, removing a burr | flash, or wash | cleaning dirt.

Further, the workpiece is provided with a cross hole opened on the inner surface of the hole so as to cross the hole, and the reflection surface of the flow control jig has a predetermined direction with respect to the axial direction of the hole. It is inclined so as to have an angle, and the jet water flow is reflected toward the cross hole through the reflection surface of the flow control jig, and the cross angle portion between the hole and the cross hole and / or the cross hole. The jet water flow containing the cavitation bubbles can be applied to the inner side surface of the gas.
In this case, the jet water flow can be efficiently guided to the intersecting hole, and the cavitation bubbles can be efficiently collapsed at the intersecting corner portion or the inner surface of the intersecting hole. Therefore, the hole surface processing can be efficiently performed on the crossing corners and the inner side surfaces of the crossing holes.

In addition, the cross hole has an opening opened on the surface of the workpiece on the side opposite to the crossing corner, and the flow control means controls the flow rate of the jet water flow flowing out from the opening. It is preferable to adjust the outflow amount of the jet water flow from the opening (claim 3).
In this case, the flow rate of the jet water flowing into the cross hole can be adjusted, and the cavitation bubbles can be collapsed in the cross hole in a state optimal for performing the surface processing of the cross hole. .

Further, the cross hole has an opening that opens on the surface of the workpiece on the side opposite to the crossing corner, and a closing means for closing the opening can be disposed in the opening. (Claim 4).
In this case, the stagnation region of the jet water flow is more easily formed in the cross hole and in the vicinity thereof. For this reason, the cavitation bubbles guided to the cross holes are sufficiently collapsed in the vicinity of the cross corners and the inner side surfaces of the cross holes, and the surface processing of the cross holes can be performed efficiently.

Further, a two-layer nozzle having a first jet port for ejecting the high-pressure water flow and a second jet port surrounding the first jet port and for ejecting the low-pressure water flow is disposed in water, and the two-layer nozzle is used to It is preferable that the jet water flow be jetted into the air.
In this case, cavitation bubbles can be generated in the jet water flow at an early stage, that is, cavitation collapse energy can be generated at a position near the nozzle tip of the two-layer nozzle. Therefore, even if the distance between the workpiece and the two-layer nozzle is reduced, the hole surface processing with cavitation bubbles can be performed sufficiently. As a result, efficient hole surface processing can be performed at a desired position.

In addition, the jet water flow is ejected from a two-layer nozzle having a first jet port for jetting the high-pressure water flow and a second jet port surrounding the first jet port and jetting the low-pressure water flow, and the first jet The mouth can also eject the high-pressure water flow in a state where the nozzle tip of the first injection port is inserted into the hole (Claim 6).
In this case, it is possible to irradiate and reflect the reflection surface of the flow control jig disposed inside the hole without reducing the pressure of the high-pressure water flow. Therefore, efficient hole surface processing can be performed.

Example 1
A metal hole surface processing method according to an embodiment of the present invention will be described with reference to FIGS.
The hole surface processing method of this example is a method of performing surface processing on the inner side surface 311 of the main hole 31 opened on the surface of the workpiece 3 as shown in FIGS.

That is, first, the flow control jig 6 having the reflection surface 61 having an angle of 90 ° with respect to the axis Z direction of the main hole 31 is arranged inside the main hole 31. Then, the jet water flow 2 including the cavitation bubbles 23 is introduced into the main hole 31 and reflected through the reflection surface 61 of the flow control jig 6. The jet water stream 2 includes a high-pressure water stream 21 and a low-pressure water stream 22 surrounding the high-pressure water stream 21.
The flow control jig 6 is made of, for example, SUS303, SUS304, resin, SCM, or the like.
As shown in FIG. 2, the clearance c between the flow control jig 6 and the inner surface 311 of the main hole 31 is 400 μm or less. In this example, the clearance c is 5 μm.

The workpiece 3 is made of aluminum and is formed by drilling the main hole 31. Note that the workpiece 3 is not limited to aluminum, and can be constituted by, for example, SCM415, SUS303, SUS304, or the like, and the present machining method can also be applied to workpieces made of resin, ceramic, or the like.
The main hole 31 has a cylindrical shape with an inner diameter of 9 mm, one opening 312 opens directly on the surface of the workpiece 3, and the other opening 313 opens on the surface of the workpiece 3 via the recess 314. is doing.

Further, in injecting the jet water stream 2 onto the workpiece 3, as shown in FIG. 1, the jet water stream 2 is jetted from the two-layer nozzle 1 arranged in water toward the workpiece 3 arranged in the air. To do.
That is, as shown in FIG. 1, the two-layer nozzle 1 having the first jet port 11 and the second jet port 12 surrounding the first jet port 11 is disposed in the water.

A high-pressure water stream 21 is ejected from the first ejection port 11 toward the air, and a low-pressure water stream 22 having a lower pressure than the high-pressure water stream 21 is ejected from the second ejection port 12 toward the air.
The jet water stream 2 composed of the high-pressure water stream 21 and the low-pressure water stream 22 surrounding the high-pressure water stream 21 includes cavitation bubbles 23.
The jet water flow 2 is introduced into the main hole 31 of the workpiece 3 disposed in the air and jetted toward the reflecting surface 61 of the flow control jig 6.

  The two-layer nozzle 1 has a high-pressure water nozzle 131 connected to the first jet port 11 and a low-pressure water nozzle 132 connected to the second jet port 12. The low-pressure water nozzle 132 is coaxially disposed so as to surround the high-pressure water nozzle 131. The high-pressure water nozzle 131 is provided with an orifice 133 at the first jet port 11. In addition, a first taper portion 134 whose diameter decreases toward the tip is formed in the outer portion of the orifice 133.

The low-pressure water nozzle 132 is formed with a second taper portion 135 whose diameter decreases toward the tip at the outer portion of the first taper portion 134.
High pressure water 210 is supplied to the high pressure water nozzle 131, and low pressure water 220 is supplied to the low pressure water nozzle 132. The supply pressure of the high-pressure water 210 is, for example, 10 to 50 MPa, and the supply pressure of the low-pressure water 220 is, for example, 0.05 to 0.1 MPa.

  Although the two-layer nozzle 1 is arranged coaxially, the processing capability can be partially increased by decentering the low-pressure water nozzle 132 with respect to the high-pressure water nozzle 131. As a result, cavitation bubbles can be concentrated on the side where the low-pressure channel is largely provided. That is, it is possible to perform surface processing more effectively by decentering the low-pressure channel on the side where the processing capability is desired to be increased.

Further, the two-layer nozzle 1 is disposed in the stored water 42 stored in the water tank 41. And the 1st spout 11 and the 2nd spout 12 have faced the vertically upper direction, and are located in the stored water 42, ie, the lower part of the water surface 421.
Specifically, the two-layer nozzle 1 is arranged at a position where the distance d between the nozzle tip 14 of the two-layer nozzle 1 and the water surface 421 is 15 mm or less.

  With such an arrangement and configuration, cavitation bubbles 23 can be generated in the two-layer jet water flow 2 at an early stage, that is, cavitation collapse energy can be generated at a position close to the nozzle tip 14 of the two-layer nozzle 1. Therefore, even if the distance between the workpiece 3 and the two-layer nozzle 1 is reduced, the hole surface processing with cavitation bubbles can be performed sufficiently.

As a result, the hole surface processing of the workpiece 3 can be performed in a narrow space. Moreover, since the distance from the two-layer nozzle 1 is short and the two-layer jet water flow 2 having a stable flow can be applied to the inner side surface 311 of the main hole 31 of the workpiece 3 through the reflecting surface 61, a desired flow rate can be obtained. The jet water stream 2 can be applied in a concentrated manner. Therefore, it is possible to efficiently perform hole surface processing on necessary portions.
Further, since the distance d between the nozzle tip 14 of the two-layer nozzle 1 and the water surface 421 is 15 mm or less, a sufficient impact force is ensured when the jet water flow 2 collides with the reflecting surface 61 of the flow control jig 6. The hole surface processing of the workpiece 3 can be sufficiently performed.

FIG. 3 is a diagram showing the entire apparatus for generating the jet water flow 2. The high-pressure water nozzle 131 of the two-layer nozzle 1 is supplied with high-pressure water 210 from the high-pressure pump 53, and the low-pressure water nozzle 132 is supplied with Low pressure water 220 is supplied from the low pressure pump 54. The high-pressure pump 53 and the low-pressure pump 54 are arranged in supply water 52 stored in a water supply tank 51 different from the water tank 41. The supply water 52 is supplied to the two-layer nozzle 1 as high-pressure water 210 and low-pressure water 220 by a high-pressure pump 53 and a low-pressure pump 54, respectively.
The high-pressure water 210 supplied to the high-pressure water nozzle 131 is jetted as the high-pressure water stream 21 from the first jet nozzle 11. The low-pressure water 220 supplied to the low-pressure water nozzle 132 is jetted as the low-pressure water stream 22 from the second jet nozzle 12.

Next, the function and effect of this example will be described.
In the hole surface processing method, the jet water stream 2 including the cavitation bubbles 23 generated by jetting the high-pressure water stream 21 and jetting the low-pressure water stream 22 so as to surround the periphery of the high-pressure water stream 21 is Reflected at the reflecting surface 61.

Then, the clearance c (FIG. 2) between the flow control jig 6 and the inner surface 311 of the main hole 31 of the workpiece 3 is set to 400 μm or less, so that the cavitation bubbles 23 flow out to the rear of the flow control jig 6. This can be prevented. Further, the cavitation bubbles 23 can be efficiently collapsed by the rapid pressure increase of the pressure of the jet water flow 2 around the reflection surface due to the reflection of the high-pressure water flow 21 on the reflection surface 61. At this time, an extremely large impact pressure is locally generated, and a sufficiently large compressive stress can be applied to the inner surface of the main hole 31 of the workpiece 3. That is, the compressive stress can be efficiently applied to the inner side surface 311 of the main hole 31.
Further, if burrs are generated on the hole surface, the burrs can be efficiently removed, and if dirt is adhered, the dirt can be efficiently cleaned.

  As described above, according to this example, it is possible to provide a hole surface processing method that can efficiently perform surface processing on the inner surface of a hole provided in a workpiece.

(Example 2)
In this example, as shown in FIGS. 4 and 5, the surface processing is performed on the cross hole 32 opened on the inner surface 311 of the main hole 31 so as to cross the main hole 31 opened on the surface of the workpiece 3. How to do it. Hereinafter, configurations not described are the same as those in the first embodiment.
That is, first, the flow control jig 6 having the reflection surface 61 inclined to the cross hole 32 side at an angle θ of 90 to 30 ° with respect to the axis Z direction of the main hole 31 is provided inside the main hole 31. Arrange it. In this example, the angle θ is 60 °.

Then, the jet water flow 2 including the cavitation bubbles 23 is introduced into the main hole 31 in the workpiece 3 and is reflected toward the cross hole 32 through the reflection surface 61 of the flow control jig 6, and crosses the main hole 31. It is applied to the crossing corner 33 between the hole 32 and the inner surface 321 of the crossing hole 32.
The flow control jig 6 is arranged so that the center 611 of the reflecting surface 61 is 1.2 to 2.0 mm above the center 329 of the cross hole 32 (upward in the axis Z direction of the main hole 31).

As shown in FIGS. 4 and 5, the cross hole 32 has an opening 322 opened on the surface of the workpiece 3 on the side opposite to the cross corner 33, and applies the jet water flow 2 to the cross hole 32. . At that time, the leakage of the water flow from the opening 322 of the cross hole 32 is controlled by disposing a leak control jig 60 as a flow rate control means in the opening 322.
The flow control jig 6 and the leak control jig 60 are made of SUS, resin, SCM, or the like.
The workpiece 3 is made of aluminum and is formed by drilling the main hole 31 and the cross hole 32. Due to this drilling process, burr may occur particularly at the crossing corner portion 33 of the crossing hole 32. This burr is removed by the hole surface processing method of the present invention.

With such a configuration, the jet water flow 2 irradiated on the reflecting surface 61 inclined at a predetermined angle is reflected toward the cross hole 32, and the cross angle portion 33 and the cross between the main hole 31 and the cross hole 32. It hits the inner surface 321 and the inner surface 311 of the hole 32. At this time, the flow rate of the jet water flow 2 flowing out from the opening 322 of the jet water flow 2 flowing into the cross hole 32 is adjusted by the leak control jig 60. Thereby, the flow velocity of the jet water flow 2 in the cross hole 32 is appropriately controlled, and it is possible to cause the desired cavitation bubbles 23 to collapse, and it is possible to perform an appropriate surface treatment on the cross hole 32. It becomes.
In addition, the same effects as those of the first embodiment are obtained.

In place of the leak control jig 60, a closing jig for closing the entire opening 322 of the cross hole 32 may be arranged.
In this case, the stagnation region of the jet water flow 2 is more easily formed in the cross hole 32 and in the vicinity thereof. Therefore, the cavitation bubble 23 guided to the cross hole 32 is sufficiently collapsed in the vicinity of the cross corner portion 33 and the inner side surface 321 of the cross hole 32, and the hole surface processing of the cross hole 32 can be performed efficiently. it can.

(Example 3)
This example relates to a hole surface processing method when the main hole 31 is elongated and the processing site 315 is greatly separated from the main hole opening 313 as shown in FIG.
In this example, the outer diameter of the high-pressure water nozzle 131 is smaller than the inner diameter of the main hole 31, and the tip 141 of the high-pressure water nozzle 131 is protruded from the tip 142 of the low-pressure water nozzle 132. And the front-end | tip 141 of the high pressure water nozzle 131 is set as the structure extended to the process site | part 315, ie, the vicinity of the reflective surface 61 of the flow control jig 6. FIG.
Others are the same as in the first embodiment.

By adopting such a configuration, it is possible to irradiate and reflect the reflecting surface 61 without reducing the pressure of the high-pressure water stream 21 ejected from the high-pressure water nozzle 131 and to realize efficient hole surface processing. Become.
In addition, the same effects as those of the first embodiment are obtained.

Example 4
This example is an example in which the leakage control jig 60 (see FIGS. 4 and 5) in the second embodiment is removed in the processing method of the workpiece having the cross holes 32 as shown in FIG.
Others are the same as in the second embodiment.
When the leak control jig 60 is not disposed and the opening 322 is opened as in this example, the jet water flow 2 guided to the cross hole 32 flows from the opening 322 to the outside. Even in this case, it is possible to generate a certain cavitation bubble 23 and to perform the surface processing of the inner side surface 321 of the intersecting hole 32 and the intersecting corner portion 33.
In addition, the same effects as those of the second embodiment are obtained.

  In Examples 1 to 4, an impact sensor capable of detecting the impact energy applied to the workpiece 3 by the jet water flow 2 is arranged on the workpiece 3 or the holding jig that holds the workpiece 3. It can also be provided (not shown). Then, the processing time is controlled based on the integrated value of the impact energy detected by the impact sensor.

For example, the relationship between the integrated value of the impact energy applied to the workpiece 3 by the jet water flow 2 and the progress of the hole surface processing is previously grasped by means such as experiments and simulations. Then, when the integrated value of the impact energy detected by the impact sensor reaches a predetermined value, the processing is finished.
A piezoelectric film sensor can be used as the impact sensor.
In this case, it is possible to easily and efficiently perform an appropriate hole surface processing on the workpiece 3.

(Comparative example)
In this example, as shown in FIG. 8, the angle θ formed by the reflection surface 61 of the flow control jig 6 and the axis Z direction of the main hole 31 is 45 °, and the flow control jig 6 and the main hole 31 In this example, the clearance c with the side surface 311 is 1.5 mm.
Others are the same as in the first embodiment.

In the case of this example, it is difficult to sufficiently remove burrs at the crossing corner portion 33 as compared to the second embodiment. In addition, the effect of applying compressive stress to the inner surface 321 of the cross hole 32 and the cleaning effect are reduced.
This is because when the clearance c is 1.5 mm and exceeds the appropriate clearance range of 400 μm or less, it becomes difficult to efficiently guide the cavitation bubbles 23 to the cross holes 32. On the inner side 321, it becomes difficult to efficiently collapse the cavitation bubbles 23. That is, when the clearance is out of the clearance range, a so-called stagnation region having a low flow velocity is hardly formed in the vicinity of the cross hole 32, so that the cavitation bubble 23 flows backward and the cavitation bubble 23 is difficult to collapse. Thereby, it becomes difficult to perform the hole surface processing of the cross hole 32 efficiently.

(Experimental example 1)
This example is an example of evaluating the processing efficiency when the hole surface processing method shown in the above embodiment is used.
The pressure of the high-pressure water 210 was 30 MPa, the pressure of the low-pressure water 220 was 0.06 MPa, and the jet water flow 2 was applied to the workpiece 3 for 60 seconds continuously. In the method of the present invention, the distance d between the nozzle tip 14 and the water surface 421 is 2 mm, and the distance between the nozzle tip 14 and the reflection surface 61 of the flow control jig 6 is 50 mm.
In addition, paint was applied to the inner side surface 321 of the cross hole 32.

And after processing by the method of Example 2, 4 and a comparative example, the erosion state in the crossing angle part 33 and the peeling state of the coating material in the inner surface 321 of the crossing hole 32 were confirmed.
This erosion state and peeling state were evaluated as processing ability. That is, it can be said that the greater the amount of erosion and the greater the amount of separation, the higher the processing energy by the jet water flow 2 including the cavitation bubbles 23 and the higher the processing capacity.
The test results are shown in Table 1.

As can be seen from Table 1, in the case of Example 2, erosion of the crossing corner portion 33 and peeling of the coating material of the crossing hole 32 occur, and there is sufficient processing capability.
Moreover, in the case of Example 4, although the erosion of the crossing angle part 33 occurs, the processing capacity to the crossing hole 32 is insufficient.
Moreover, in the case of a comparative example, neither the erosion of the crossing angle part 33 nor the peeling of the coating material of the crossing hole 32 occurs, and the processing ability is inferior to that of Example 2.
From the above, it can be seen that according to the present invention, in particular, the method of Example 2, the cross hole 32 can be efficiently subjected to the hole surface processing.

(Experimental example 2)
In this example, as shown in FIG. 8, the relationship between the size of the clearance c between the flow control jig 6 and the inner surface 311 of the main hole 31 of the workpiece 3 and the amount of erosion was examined.
That is, in the hole surface processing method shown in Example 1, the pressure of the high-pressure water 210 is set to 30 MPa and the pressure of the low-pressure water 220 is set to 0.06 MPa, and the inner surface 311 of the main hole 31 of the workpiece 3 is continuously 60 seconds. The jet water flow 2 was applied through the flow control jig 6. The distance d between the nozzle tip 14 and the water surface 421 was 2 mm, and the distance between the nozzle tip 14 and the reflecting surface 61 of the flow control jig 6 was 50 mm.

And the said clearance c was changed variously by changing the outer diameter of the flow control jig | tool 6 variously, said hole surface processing was performed, and the amount of erosion in each case was measured.
The measurement results are shown in FIG.
As can be seen from the figure, the smaller the clearance c, the greater the amount of erosion.

  If the clearance c is 400 μm or less, the amount of erosion becomes 5 mg or more, and it becomes possible to apply substantial compressive stress, clean and remove dirt, and remove burrs. In addition, when the clearance c exceeds 400 μm, it may be difficult to efficiently guide the jet water flow 2 to the main hole 31. When the clearance c is 1.5 mm, the amount of erosion becomes less than 2 mg, and it may be difficult to sufficiently perform the hole surface processing.

Sectional explanatory drawing which shows the hole surface processing method in Example 1. FIG. Sectional explanatory drawing of the to-be-processed object which has arrange | positioned the flow control jig | tool in Example 1. FIG. BRIEF DESCRIPTION OF THE DRAWINGS General explanatory drawing which shows the apparatus for generating a jet water flow in Example 1. FIG. Sectional explanatory drawing which shows the hole surface processing method in Example 2. FIG. Sectional explanatory drawing of the to-be-processed body which has arrange | positioned the flow control jig in Example 2. FIG. Sectional explanatory drawing which shows the hole surface processing method in Example 3. FIG. Sectional explanatory drawing of the to-be-processed body which has arrange | positioned the flow control jig | tool in Example 4. FIG. Sectional explanatory drawing of the to-be-processed object which has arrange | positioned the flow control jig | tool in a comparative example. The diagram which shows the relationship between clearance and the amount of erosion in Experimental example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Two-layer nozzle 2 Jet water flow 21 High pressure water flow 22 Low pressure water flow 23 Cavitation bubble 3 Work piece 31 Main hole 311 Inner side surface 32 Cross hole 321 Inner side surface 33 Crossing corner 6 Flow control jig 60 Leak control jig 61 Reflective surface

Claims (6)

A method of processing an inner surface of the hole by ejecting a jet water flow having a predetermined water pressure inside a hole drilled in a workpiece,
The jet stream is a two-layer jet stream composed of a high-pressure stream and a low-pressure stream surrounding the high-pressure stream, including cavitation bubbles,
A flow control jig having a reflective surface for reflecting the high-pressure water flow is disposed inside the hole,
The clearance between the flow control jig and the inner surface of the hole is 400 μm or less,
The hole surface processing method according to claim 1, wherein the jet water stream is applied to an inner surface of the hole by jetting the high-pressure water stream to the reflecting surface and reflecting the jet.   In Claim 1, the said to-be-processed object provides the cross hole opened on the inner surface of this hole so that it may cross | intersect the said hole, and the said reflective surface of the said flow control jig | tool is an axial direction of the said hole. And the jet water flow is reflected toward the cross hole through the reflection surface of the flow control jig, and an intersection angle portion between the hole and the cross hole, and / or The hole surface processing method, wherein the jet water flow containing the cavitation bubbles is applied to an inner surface of the cross hole.   3. The flow rate control according to claim 2, wherein the cross hole has an opening portion opened on a surface of the workpiece on a side opposite to the cross corner portion, and controls a flow rate of the jet water flow flowing out from the opening portion. The hole surface processing method characterized by adjusting the outflow amount of the jet water flow from the opening by means.   3. The crossing hole according to claim 2, wherein the crossing hole has an opening that opens on the surface of the workpiece on the side opposite to the crossing corner, and a closing unit that closes the opening is disposed in the opening. The hole surface processing method characterized by the above-mentioned. 5. The two-layer nozzle according to claim 1, wherein a two-layer nozzle having a first jet port that jets the high-pressure water flow and a second jet port that surrounds the first jet port and jets the low-pressure water flow is The hole surface processing method characterized by arrange | positioning and ejecting the said jet water flow toward air | atmosphere from this two-layer nozzle.   In any one of Claims 1-5, From the two-layer nozzle which has the 1st jet nozzle which ejects the said high pressure water flow, and the 2nd jet nozzle which surrounds this 1st jet port, and ejects the said low pressure water flow, A hole surface processing method, wherein a jet water stream is jetted and the first jet port jets the high-pressure water stream in a state where a nozzle tip of the first jet port is inserted into the hole.

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