JP2010214477A - Surface treatment method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a sufficient surface treatment effect by causing sufficient bubble collapse, even in treating a treated surface made of a convex curved surface in surface treatment using cavitation peening. <P>SOLUTION: A vortex flow generating tool 5 is provided on an upstream side of a treated object 2 on a jet center axis C. and a flow of cavitation jet 3 is converted into a vortex flow 4 by making the cavitation jet 3 flow along an outer peripheral side surface 5a of the vortex flow generating tool 5. Alternatively, a vortex flow damming tool 6 is provided on a downstream side of the treated object 2 on the jet center axis C. By damming the cavitation jet 3 by a damming surface 6a of the vortex flow damming tool 6, the vortex flow 4 contained in the cavitation jet 3 is suppressed from being made to flow to the downstream side. The vortex flow 4 is collected in the vicinity of the treated surface 2a by the vortex flow generating tool 5 or the vortex flow damming tool 6, and cavitation bubbles in the vortex flow 4 are collapsed in the vicinity of the treated surface 2a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface treatment method and a surface treatment apparatus, and more particularly to a surface treatment method and a surface treatment apparatus for treating a surface to be processed having a convex curved surface using cavitation peening.

  Conventionally, surface treatment using cavitation peening has been performed for the purpose of strengthening the surface of a metal material or a semiconductor material, cleaning, improving residual stress, and the like. Moreover, as a technique for improving the processing efficiency of cavitation peening, there are disclosed a technique for ejecting nozzles that generate more cavitation and a technique for arranging a large number of ejection nozzles in order to process a large area (for example, Patent Document 1). 2, 3).

  Cavitation is a phenomenon in which liquid becomes bubbles as a result of the pressure of a liquid such as flowing water being locally reduced and the pressure decreasing to the saturated vapor pressure of the liquid. In many cases, fine bubbles dissolved in water serve as cavitation nuclei and become cavitation bubbles in a high-speed region (low-pressure region) of the jet. The cavitation bubbles generated by the decrease in the pressure of the liquid will collapse due to the influence of the surface tension of the liquid and the like if the pressure of the liquid is increased again due to the decrease in the flow velocity. This bubble collapse occurs in a short time on the order of several microseconds. For this reason, an impact pressure that reaches several hundred to several thousand atmospheres is generated at the time of bubble collapse.

  In the surface treatment by cavitation peening, the surface of the object to be treated is strengthened by using the impact pressure generated when the cavitation bubbles collapse. That is, as shown in FIG. 14, a liquid cavitation jet (a jet of water such as water containing cavitation bubbles) 73 ejected from the ejection nozzle 71 collides with the surface of the workpiece 72. The cavitation jet 73 after colliding with the workpiece 72 flows along the workpiece surface 72a, and the flow velocity of the cavitation jet 73 decreases in the process. Thereby, the pressure of the cavitation jet 73 rises and bubble collapse occurs. And the to-be-processed surface 72a is strengthened by the impact pressure generated at this time.

  Here, as the radius of curvature of the workpiece 72 increases with respect to the diameter of the cavitation jet 73 (that is, the diameter of the jet nozzle 71), the velocity reduction region of the cavitation jet 73 after colliding with the workpiece 72 is increased. Therefore, it becomes possible to ensure good processing efficiency.

JP-A-9-108596 Japanese Patent No. 3803734 JP 2007-260550 A

  By the way, in the surface treatment by cavitation peening, in order to enhance the surface more efficiently, more cavitation bubbles are collapsed in the vicinity of the treated surface of the workpiece, and the impact pressure generated at that time is reduced. It is important to apply more to the surface to be processed.

  However, as shown in FIG. 15, when the surface 82a of the workpiece 82 is a convex curved surface and its radius of curvature is small, the flow velocity of the cavitation jet 83 after colliding with the workpiece 82 is In the vicinity of 82a, it may not decrease to the extent that bubble collapse occurs.

  For example, when the surface to be processed 82a is a convex curved surface having a radius of curvature smaller than about 5 mm, a part of the cavitation jet 83 after colliding with the object to be processed 82 does not decrease the flow velocity to the extent that bubble collapse occurs. , It will flow away from the surface 82a. If it does so, bubble collapse will not fully occur, but processing, such as reinforcement of processed surface 82a, will become insufficient.

  Even in this case, if the processing time is lengthened, the surface 82a to be processed may be sufficiently strengthened, but this causes a reduction in processing efficiency. Further, when the diameter of the injection port of the injection nozzle 81 is reduced in accordance with the small radius of curvature of the surface to be processed 82a, the processing area is also reduced, which also causes a reduction in processing efficiency.

  The present invention has been made in view of the above circumstances, and in the surface treatment using cavitation peening, even when a surface to be processed having a convex curved surface is processed, sufficient bubble collapse is generated and sufficient. It is a technical problem to be solved to achieve the surface treatment effect.

  Hereinafter, each means suitable for solving the above-described problems will be described with additional effects and the like as necessary.

  (1) In the surface treatment method according to claim 1, which solves the above problem, a cavitation bubble is collided by colliding a cavitation jet against an object to be processed having a convex curved surface, and an impact generated when the bubble collapses. A method of treating the surface to be treated by pressure, wherein the surface to be treated is disposed on a central axis of the cavitation jet ejected from an ejection nozzle and upstream of the workpiece, and the cavitation jet is self-actuated. A vortex generating jig having a three-dimensional vortex generating function for converting the flow of the cavitation jet into a vortex by flowing along the surface of the nozzle, and on the jet central axis and downstream of the workpiece. And vortex flow contained in the cavitation jet by damming the cavitation jet at its surface Using any one or both of the three-dimensional vortex damming jig having a vortex damming function that suppresses the flow to the downstream side, the eddy current generation function and / or the eddy current damming function, The eddy current is collected in the vicinity of the surface to be processed of the object to be processed, and the cavitation bubbles in the vortex are collapsed in the vicinity of the surface to be processed.

  When a cavitation jet collides with a workpiece whose surface to be processed is a convex curved surface, the velocity of the cavitation jet after the collision decreases in the process of flowing along the surface to be processed. However, if the radius of curvature of the surface to be processed, which is a convex curved surface, is small, a part of the cavitation jet may flow away from the surface to be processed without reducing the flow velocity to the extent that bubble collapse occurs. Then, sufficient bubble collapse does not occur.

  In this regard, in the surface treatment method according to claim 1, the eddy current is collected in the vicinity of the surface to be processed of the workpiece by the eddy current generating function of the eddy current generating jig and / or the eddy current blocking function of the eddy current blocking jig. Thus, it is possible to collapse the cavitation bubbles in the vortex near the surface to be processed.

  Since the flow speed of the vortex is high, the pressure in the vortex is low. As this pressure drops to the saturated vapor pressure of the liquid, cavitation bubbles are generated in the vortex. The vortex flow velocity decreases with time, and as the vortex flow attenuates, the pressure in the vortex increases and the cavitation bubbles collapse.

  The cavitation bubbles in the vortex flow include bubbles that existed in the cavitation jet before the formation of the vortex flow, bubbles that have become larger in diameter due to pressure drop due to the formation of the vortex flow, and vortex flow. Any bubbles newly generated as a result of formation are included.

  Therefore, according to the surface treatment method of claim 1, even when the surface to be processed is a convex curved surface and the radius of curvature is small, sufficient bubble collapse can occur near the surface to be processed. it can. Therefore, the impact pressure generated when the bubbles collapse can be sufficiently applied to the surface to be processed, and the surface to be processed can be reliably processed and the processing efficiency can be improved.

  Further, in this surface treatment method, the eddy current can be efficiently generated by a simple method of arranging the eddy current generating jig in the flow of the cavitation jet. The cross-sectional shape of the eddy current generating jig is not particularly limited as long as it can efficiently generate eddy currents, but is circular, elliptical with a major axis in the direction of the jet central axis, and has an apex angle on the jet central axis. A cross-sectional shape such as an acute isosceles triangle can be used.

  Further, in this surface treatment method, the eddy current can be efficiently dammed by a simple method of arranging a vortex damming jig on the downstream side of the cavitation jet, and the vortex can be retained longer in the vicinity of the workpiece. . The cross-sectional shape of the eddy current generating jig is not particularly limited as long as the cavitation jet flowing along the processing surface of the workpiece can be received without leakage on the surface of the eddy current blocking jig. The length of the surface (damming surface) of the fixing jig is preferably a plate-like cross-sectional shape that is set sufficiently larger than the diameter of the workpiece.

  (2) The surface treatment method according to claim 2 is the surface treatment method according to claim 1, wherein a plurality of the objects to be processed are arranged on both sides away from the jet central axis, and the eddy current generation treatment is performed. The eddy current is collected in the vicinity of each surface to be processed of a plurality of objects to be processed by means of a tool.

  In this surface treatment method, since the cavitation jet jetted from a single jet nozzle can be branched and the surface treatment of a plurality of workpieces can be performed simultaneously, the processing efficiency can be improved. Moreover, since a plurality of injection nozzles are not required, it contributes to a reduction in equipment costs.

  (3) The surface treatment apparatus according to claim 3, which solves the above problem, causes a cavitation bubble to collide with an object having a surface to be processed having a convex curved surface to collapse a cavitation bubble, and an impact generated when the bubble collapses An apparatus for processing the surface to be processed by pressure, an injection nozzle for injecting the cavitation jet, a central axis of the cavitation jet to be injected from the injection nozzle, and upstream of the object to be processed And a vortex generating jig having a three-dimensional vortex generating function for converting the flow of the cavitation jet into a vortex by flowing the cavitation jet along its own surface, and the jet central axis. And arranged downstream of the object to be treated and blocking the cavitation jet on its own surface. The eddy current generation is provided with either or both of a three-dimensional vortex damming jig having a vortex damming function that suppresses the vortex contained in the cavitation jet from flowing downstream. The vortex flow is collected in the vicinity of the surface to be processed of the object to be processed by the function and / or the eddy current blocking function, and the cavitation bubbles in the vortex flow are collapsed in the vicinity of the surface to be processed. To do.

  The effect by performing the surface treatment of the object to be processed by this surface treatment apparatus is the same as the effect in the surface treatment method according to claim 1.

  (4) The surface treatment apparatus according to claim 4 is the surface treatment apparatus according to claim 3, wherein the surface of the eddy current generating jig and / or the eddy current damming jig facing the surface to be processed is The surface to be processed is shaped along the curvature in the axial direction.

  By performing the surface treatment of the object to be processed by this surface treatment apparatus, the surface to be processed has a curvature in the axial direction of the object to be processed, that is, the object is processed in the axial direction of the object to be processed. Even if the cross-sectional shape of the object is a rod-shaped object to be processed, the distance between the surface of the object to be processed of the eddy current generating jig and / or the eddy current blocking jig and the surface of the object to be processed is Since a constant interval is maintained over the axial direction of the object to be processed, it is possible to perform a uniform surface treatment in the axial direction of the surface of the object to be processed.

  Therefore, according to the surface treatment method and the surface treatment apparatus of the present invention, even when a surface to be processed having a convex curved surface is processed, sufficient bubble collapse can be generated to achieve a sufficient surface treatment effect. it can.

  Therefore, for example, a sufficient surface treatment effect can be achieved even for a surface to be processed which is a convex curved surface having a radius of curvature of about 5 mm or less.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram explaining the principle of the surface treatment method of this invention, Comprising: (a) is Embodiment 1 with which the eddy current generation jig | tool is arrange | positioned between an injection nozzle and a to-be-processed object, (b) Embodiment 2 is shown in which a vortex damming jig is arranged on the downstream side of the processed material. It is a cross-sectional schematic diagram explaining the surface treatment method which concerns on Embodiment 3. FIG. It is a cross-sectional schematic diagram explaining the surface treatment method which concerns on Embodiment 4. FIG. It is a cross-sectional schematic diagram explaining the surface treatment method according to Embodiment 5. It is a cross-sectional schematic diagram explaining the surface treatment method which concerns on Embodiment 6. FIG. 2 is a schematic cross-sectional view illustrating a surface treatment method according to Example 1. FIG. 6 is a schematic cross-sectional view illustrating a surface treatment method according to Example 2. FIG. 10 is a schematic cross-sectional view illustrating a surface treatment method according to Example 3. FIG. 6 is a schematic cross-sectional view illustrating a surface treatment method according to Example 4. FIG. 10 is a schematic cross-sectional view illustrating a surface treatment method according to Example 5. FIG. In Examples 1, 2, and 4 and Comparative Examples 1 and 2, it is a figure which shows the result of having measured the area (processed area) of the erosion area | region about the to-be-processed surface after surface treatment. In Example 3 and 5 and Comparative example 3 and 4, it is a figure which shows the result of having measured the residual stress about the to-be-processed surface after surface treatment. In Example 3 and 5 and Comparative Example 3 and 4, it is a figure which shows the processing time required until surface treatment was completed over the full length of a to-be-processed object (round bar). It is a cross-sectional schematic diagram explaining the surface treatment method using the conventional cavitation peening. It is a cross-sectional schematic diagram explaining the surface treatment method using the other conventional cavitation peening.

  Hereinafter, specific embodiments of the surface treatment method and the surface treatment apparatus of the present invention will be described in detail. In addition, embodiment described is only one Embodiment, The surface treatment method and surface treatment apparatus of this invention are not limited to the following embodiment. The surface treatment method and the surface treatment apparatus of the present invention can be carried out in various forms that have been modified or improved by those skilled in the art without departing from the scope of the present invention.

(Embodiment 1)
The surface treatment apparatus according to the first embodiment shown in FIG. 1A includes an injection nozzle 1 and an eddy current generating jig 5 disposed between the injection nozzle 1 and the workpiece 2. The injection nozzle 1 and the eddy current generating jig 5 are immersed in water filled in a processing tank (water tank) (not shown) together with the workpiece 2.

The injection nozzle 1 of the jet central axis on C, the axis O of the object 2, and the axis O ₁ of the vortex generating jig 5 are arranged in a straight line. Injection nozzle 1 on him a collision center P ₁ of the jet central axis C of the vortex generator jig 5, to inject a cavitation jet 3 at a predetermined pressure. The jet nozzle 1 is moved in a direction perpendicular to the jet central axis C of the cavitation jet 3 jetted from the jet nozzle 1 by a jet nozzle moving device (not shown) and in the longitudinal direction of the workpiece 2 (in FIG. ) Can be reciprocated.

  The workpiece 2 is made of a metal material such as an aluminum alloy and is a round bar (column) having a radius r. The outer peripheral side surface (cylindrical side surface) of the workpiece 2 is the processing surface 2a. The surface 2a to be processed is a convex curved surface (cylindrical side surface) having a radius of curvature r. The workpiece 2 can be rotated around the axis O of the workpiece 2 in the forward direction and the reverse direction (clockwise direction and counterclockwise direction in FIG. 1A) by a rotation driving device (not shown). Has been.

Vortex generators jig 5 is made of a metal material such as stainless steel, a round bar having a radius r ₁ (cylinder). The radius r ₁ of the eddy current generating jig 5 is set to be equal to or less than the radius r of the processed object 2 so that the upstream eddy current generating jig 5 does not largely shield the downstream processed object 2. Has been. If the radius r ₁ is too small, the eddy current generating function of the eddy current generating jig 5 is remarkably impaired. Therefore, the lower limit of the radius r ₁ needs to be large enough to obtain a desired eddy current generating function. The eddy current generating jig 5 includes a support center (not shown) and a collision center portion P on the jet central axis C of the workpiece 2 and a downstream central portion Q ₁ on the jet central axis C of the eddy current generating jig 5. spacing is arranged such that D _1.

  Here, the shape and size of the object to be processed 2 are not particularly limited as long as the object 2 has a surface 2a to be processed having a predetermined convex curved surface. According to the surface treatment apparatus of this embodiment, since it is possible to collapse many cavitation bubbles in the vicinity of the surface 2a to be processed 2, it is conventionally difficult to ensure good processing efficiency. By applying it to the workpiece 2 having a convex curved surface with a radius of curvature smaller than about 5 mm, it is possible to ensure better processing efficiency compared to conventional cavitation peening.

  Preferably, when the radius of curvature r of the convex curved surface constituting the surface 2a to be processed is 1 mm to 5 mm, more preferably when the radius of curvature r is 2 mm to 4 mm, the effect of improving the processing efficiency with respect to the conventional cavitation peening Becomes prominent.

Incidentally, the radius of curvature r of the convex curved surface constituting the treated surface 2a is too small, it is necessary to reduce also the radius r ₁ of the vortex generating jig 5 accordingly. If the radius r _{1 of the} eddy current generating jig 5 is too small, the eddy current generating function of the eddy current generating jig 5 is significantly impaired, and the effect of reducing the flow velocity of the cavitation jet 3 by the eddy current generating jig 5 is also reduced. Thereby, the collapse of cavitation bubbles in the vicinity of the surface to be processed 2a is reduced.

  On the other hand, if the radius of curvature r of the convex curved surface constituting the surface to be processed 2a is too large, even if the eddy current generating jig 5 is not arranged, the cavitation jet 3 that collides with the object to be processed 2 has a flow velocity after the collision. Is sufficiently reduced, the collapse of cavitation bubbles in the vicinity of the surface 2a to be processed increases. Therefore, even if it becomes possible to collapse more cavitation bubbles by arranging the eddy current generating jig 5, the effect of improving the processing efficiency by arranging the eddy current generating jig 5 is not significant. .

  A surface treatment method according to this embodiment using the surface treatment apparatus having the above configuration will be described below.

In water, on him the swirl generating jig jet central axis collision center P ₁ from the collision center P ₁ from the distance L ₁ apart injection nozzle 1 on C 5, a predetermined time at a predetermined pressure, the cavitation jet 3 is injected. At this time, the cavitation jet 3 may be jetted while rotating the workpiece 2, or the direction perpendicular to the jet central axis C of the cavitation jet 3 jetted from the jet nozzle 1 and the longitudinal direction of the workpiece 2 ( In FIG. 1A, the cavitation jet 3 may be jetted while moving the jet nozzle 1 in the direction perpendicular to the paper surface.

When the cavitation jet 3 collides with the collision center portion P ₁ of the eddy current generating jig 5, the cavitation jet 3 after the collision flows along the outer peripheral side surface (cylindrical side surface) 5 a of the eddy current generating jig 5. The flow velocity of the jet 3 is slightly reduced. Further, in the process in which the cavitation jet 3 flows to the downstream side of the outer peripheral side surface 5 a of the eddy current generating jig 5, the flow of the cavitation jet 3 is separated from the outer peripheral side surface 5 a, and a part of the cavitation jet 3 becomes the vortex flow 4.

Since the pressure in the vortex 4 is low, cavitation bubbles are generated. As time elapses while the vortex 4 flows downstream, the vortex 4 attenuates and the pressure increases as the vortex 4 attenuates, so that the cavitation bubbles collapse. So that the position of the vortex 4 is attenuated is the vicinity of the treatment surface 2a of the object 2, the interval of the collision center P of the object 2, a center portion to Q ₁ downstream of the vortex generator jig 5 by D ₁ is set, a wide processing area 2b on the processed surface 2a of the object 2 is formed.

The pressure of the cavitation jet 3 jetted from the jet nozzle 1, the distance L ₁ from the jet port of the jet nozzle 1 to the collision center P ₁ of the eddy current generation jig 5, the collision center P of the workpiece 2 and the eddy current generation jig The distance D ₁ with respect to the central portion Q ₁ on the downstream side of 5, the processing time, and the like can be appropriately set according to the material of the object to be processed 2, the type of processing on the surface 2 a to be processed, and the like.

For example, the workpiece 2 is made of an aluminum alloy round bar with a radius r of ₁ mm to 5 mm, the eddy current generating jig 5 is made of a stainless steel round bar with a radius r ₁ of 1 mm to 5 mm, and the treated surface 2a of the workpiece 2 is processed. In the case of processing for the purpose of strengthening, the pressure of the cavitation jet 3 is about 10 MPa to 30 MPa, the distance L ₁ from the injection port of the injection nozzle 1 to the collision center P ₁ of the vortex generator 5 is about 10 mm to 80 mm, The distance D ₁ between the collision center portion P of the workpiece 2 and the central portion Q ₁ on the downstream side of the vortex generator 5 is about 1 mm to 3 mm, and the processing time per 1 mm of the length of the workpiece 3 is 5 seconds to It can be about 30 seconds.

  Therefore, according to the surface treatment method according to the present embodiment, the workpiece 2 is not affected by the shape or size of the workpiece 2 by the eddy current generating jig 5 arranged on the upstream side of the workpiece 2. Cavitation bubbles due to the vortex 4 can be generated in the vicinity of the processing surface 2a on the upstream side. For this reason, even when the processing surface 2a of the processing object 2 is a convex curved surface and the curvature radius r is small, sufficient bubble collapse can be generated in the vicinity of the processing surface 2a. Therefore, the impact pressure generated at the time of bubble collapse can be applied to the wide processing region 2b of the processing surface 2a, and the processing surface 2a can be reliably processed and the processing efficiency can be improved.

(Embodiment 2)
The surface treatment apparatus according to Embodiment 2 shown in FIG. 1B includes an injection nozzle 1 and a vortex damming jig 6 disposed on the downstream side of the workpiece 2. The spray nozzle 1 and the eddy current blocking jig 6 are immersed in the water filled in a processing tank (water tank) (not shown) together with the workpiece 2.

The injection nozzle 1 of the jet central axis on C, the axis O of the object 2, and Sekitomemen 6a center P ₂ of the vortex dam jig 6 is arranged in a straight line. The injection nozzle 1 injects the cavitation jet 3 with a predetermined pressure aiming at the collision center portion P on the jet central axis C of the workpiece 2. The jet nozzle 1 is moved in a direction perpendicular to the jet central axis C of the cavitation jet 3 jetted from the jet nozzle 1 by a jet nozzle moving device (not shown) and in the longitudinal direction of the workpiece 2 (FIG. 1B). ) Can be reciprocated.

  Since the material, shape, preferable dimensions, and operation of the workpiece 2 are the same as those of the workpiece 2 shown in the first embodiment, the description thereof is omitted.

The vortex damming jig 6 is a plate made of a metal material such as stainless steel, and is arranged so that the damming surface 6a of the vortex damming jig 6 is perpendicular to the jet central axis C. In order to receive the cavitation jet 3 flowing along the surface 2 a of the workpiece 2 without leakage from the damming surface 6 a of the eddy current blocking jig 6, half of the damming surface 6 a of the eddy current blocking jig 6. length b ₂ is set sufficiently larger than the radius r of the object 2. The vortex damming jig 6 is formed by a support (not shown) between the center Q on the downstream side of the jet central axis C of the workpiece ₂ and the center P2 of the damming surface 6a of the vortex damming jig 6. spacing is arranged such that D _2.

  A surface treatment method according to this embodiment using the surface treatment apparatus having the above configuration will be described below.

In water, on him a collision center P from the jet nozzle 1 remote from the collision center P of the object 2 by a distance L _2, a predetermined time at a predetermined pressure, injecting the cavitation jet 3. At this time, the cavitation jet 3 may be jetted while rotating the workpiece 2, or the direction perpendicular to the jet central axis C of the cavitation jet 3 jetted from the jet nozzle 1 and the longitudinal direction of the workpiece 2 ( In FIG. 1B, the cavitation jet 3 may be jetted while moving the jet nozzle 1 in the direction perpendicular to the paper surface.

  When the cavitation jet 3 collides with the collision center portion P of the workpiece 2, some cavitation bubbles of the cavitation jet 3 collapse near the collision center portion P, and the treatment surface 2a on the upstream side of the workpiece 2 is collapsed. A narrow processing region 2b is formed. In addition, in the vicinity of the collision center portion P of the workpiece 2, the cavitation bubbles 3 are not easily collapsed because the flow velocity of the cavitation jet 3 is not sufficiently reduced. For this reason, the vicinity of the collision center portion P is a portion where the surface treatment is harder to proceed than the processing region 2b formed on both sides of the collision center portion P.

  The cavitation jet 3 after colliding with the collision center portion P flows along the surface 2a to be processed 2 of the workpiece 2, and the flow velocity of the cavitation jet 3 slightly decreases in the process. Further, in the process in which the cavitation jet 3 flows to the downstream side of the processing surface 2 a of the workpiece 2, the flow of the cavitation jet 3 is separated from the processing surface 2 a, and a part of the cavitation jet 3 becomes a vortex flow 4.

  Since the pressure in the vortex 4 is low, cavitation bubbles are generated. The vortex 4 decays with time, and the pressure increases as the vortex 4 decays, causing the cavitation bubbles to collapse. The eddy current 4 is dammed while the eddy current 4 is about to flow downstream with the damming surface 6a of the eddy current damming jig 6 so that the position where the eddy current 4 is attenuated is in the vicinity of the surface 2a to be processed. When the cavitation jet 3 collides with the damming surface 6a of the damming jig 6 and is reflected, a further vortex 4 is generated. Thereby, a wide processing region 2b is formed on the processing surface 2a on the downstream side of the processing object 2.

The pressure of the cavitation jet 3 jetted from the jet nozzle 1, the distance L ₂ from the jet port of the jet nozzle 1 to the collision center P of the workpiece ₂ , the central portion Q on the downstream side of the workpiece 2 and the eddy current dam The distance D _{2 from} the center P ₂ of the damming surface 6a of the tool 6 and the processing time can be appropriately set according to the material of the processing object 2 and the type of processing for the processing surface 2a.

For example, when the object 2 is made of an aluminum alloy round bar having a radius r of 1 mm to 5 mm and the object 2 is processed for the purpose of strengthening the surface 2a to be processed, the pressure of the cavitation jet 3 is about 10 MPa to 30 MPa. The distance L ₂ from the injection port of the injection nozzle 1 to the collision center portion P of the workpiece 2 is about 10 mm to 80 mm, the central portion Q on the downstream side of the workpiece 2 and the blocking surface of the eddy current blocking jig 6 The distance D _{2 from} the center P _{2 of} 6a can be about 1 mm to 3 mm, and the processing time per 1 mm length of the workpiece 3 can be about 5 seconds to 30 seconds.

  Therefore, according to the surface treatment method according to the present embodiment, the eddy current blocking jig 6 disposed on the downstream side of the workpiece 2 is used to dam the vortex 4 that is about to flow downstream and further vortex 4 Therefore, cavitation bubbles due to the vortex 4 can be generated in the vicinity of the surface 2a to be processed on the downstream side of the object 2 to be processed. For this reason, even when the processing surface 2a of the processing object 2 is a convex curved surface and the curvature radius r is small, sufficient bubble collapse can be generated in the vicinity of the processing surface 2a. Therefore, the impact pressure generated at the time of bubble collapse can be applied to the wide processing region 2b of the processing surface 2a, and the processing surface 2a can be reliably processed and the processing efficiency can be improved.

(Embodiment 3)
The surface treatment apparatus according to the third embodiment shown in FIG. 2 includes both the eddy current generating jig 5 shown in the first embodiment and the eddy current blocking jig 6 shown in the second embodiment.

  Other configurations in the surface treatment apparatus according to the present embodiment are the same as those in the first and second embodiments, and thus description thereof is omitted.

  In the present embodiment, the surface treatment method similar to that of the first embodiment is performed on the upstream side of the workpiece 2, and the surface treatment method similar to that of the second embodiment is performed on the downstream side of the workpiece 2. Thereby, the impact pressure generated at the time of bubble collapse can be applied to the wide processing region 2b formed on the upstream side and the downstream side of the processing surface 2a of the processing object 2, and the processing surface 2a is reliably processed. At the same time, the processing efficiency can be improved. That is, the operational effects of the present embodiment have the operational effects of the first and second embodiments.

(Embodiment 4)
The surface treatment apparatus according to the fourth embodiment shown in FIG. 3 is obtained by changing the shape of the eddy current generating jig 5 in the first embodiment.

That is, the eddy current generating jig 7 in the surface treatment apparatus according to the present embodiment is made of a metal material such as stainless steel and has an elliptical cross-sectional shape having a long axis in the direction of the jet central axis C. The length of the short axis of the eddy current generating jig 7 is approximately the same as the diameter of the eddy current generating jig 5 having the circular cross-sectional shape shown in the first embodiment (twice the radius r ₁ ). The length of the short axis of the generating jig 7 is about 1.5 times the diameter of the eddy current generating jig 5 shown in the first embodiment.

  Other configurations of the surface treatment apparatus according to the present embodiment are the same as those of the first embodiment, and thus description thereof is omitted.

  In this embodiment, since the cross-sectional shape of the eddy current generating jig 7 is an ellipse, the eddy current generating jig 7 is less likely to become the resistance of the cavitation jet 3 compared to the eddy current generating jig 5 shown in the first embodiment. . Therefore, the decrease in the flow velocity of the cavitation jet 3 in the process in which the cavitation jet 3 flows along the outer peripheral side surface 7 a of the vortex generating jig 7 is small. Compared with the eddy current generating jig 5 shown in the first embodiment, the flow of the cavitation jet 3 is not easily separated from the outer peripheral side surface 7a of the eddy current generating jig 7, and the formation of the eddy current 4 is slightly less.

  Further, as compared with the eddy current generating jig 5 shown in the first embodiment, the eddy current generating jig 7 does not easily block the flow of the cavitation jet 3, so that the cavitation jet 3 reaches the collision center P of the workpiece 2 and the vicinity thereof. It is easy to reach and the processing area 2b formed on the processing surface 2a of the processing object 2 can be brought close to the collision center P.

  Such a surface treatment apparatus according to this embodiment can be suitably used when the flow velocity of the cavitation jet 3 ejected from the ejection nozzle 1 is small because the eddy current generating jig 7 is unlikely to become the resistance of the cavitation jet 3. Other functions and effects are the same as those of the first embodiment.

(Embodiment 5)
The surface treatment apparatus according to the fifth embodiment shown in FIG. 4 is an apparatus for simultaneously performing the surface treatment of a plurality of objects to be processed 2, and the number and arrangement of the objects to be processed 2 are changed.

That is, in the surface treatment apparatus according to the present embodiment, in order to simultaneously perform the surface treatment of the two workpieces 2, the workpieces 2 are arranged on the downstream side of the eddy current generating jig 8 and the jet central axis. Arranged at equal intervals from the jet central axis C across C, and arranged so that the line connecting the axial cores O of the workpieces 2 is perpendicular to the jet central axis C. Therefore, a line connecting the axis O ₂ of the shaft center O and vortex generators jig 8 of the object 2 has an inclination of an angle θ with respect to the jet central axis C. For example, when the sizes of the workpiece 2 and the eddy current generating jig 8 are approximately the same, the angle θ may be appropriately set in the range of 25 ° to 45 °. In addition, since the material, shape, preferable dimension, and operation | movement of the to-be-processed object 2 are the same as the to-be-processed object 2 shown in Embodiment 1, description is abbreviate | omitted.

Vortex generators jig 8 is made of a metal material such as stainless steel, a round bar having a radius r ₂ (cylinder). The axis O ₂ of the eddy current generating jig 8 is disposed on the jet central axis C. The radius r ₂ of the eddy current generating jig 8 is equal to or larger than the radius r of the workpiece 2.

  Other configurations of the surface treatment apparatus according to the present embodiment are the same as those of the first embodiment, and thus description thereof is omitted.

  In the present embodiment, similarly to the surface treatment method shown in the first embodiment, the flow velocity of the cavitation jet 3 slightly decreases in the process in which the cavitation jet 3 flows along the outer peripheral side surface 8a of the eddy current generating jig 8. Further, in the process in which the cavitation jet 3 flows to the downstream side of the outer peripheral side surface 8 a of the eddy current generating jig 8, the flow of the cavitation jet 3 is separated from the outer peripheral side surface 8 a, and a part of the cavitation jet 3 becomes the vortex flow 4.

  The vortex flow 4 is formed at two locations on the downstream side of the upper outer peripheral side surface 8a and on the downstream side of the lower outer peripheral side surface 8a. The upper vortex 4 is attenuated in the vicinity of the processing surface 2a of the workpiece 2 disposed above the jet central axis C, and the lower vortex 4 is disposed on the workpiece 2 disposed below the jet central axis C. Each workpiece 2 is arranged with respect to the eddy current generating jig 8 so as to be attenuated in the vicinity of the workpiece surface 2a.

  Accordingly, the cavitation bubbles generated by the vortex flows 4 formed at two locations above and below the eddy current generating jig 8 are collapsed in the vicinity of the surface to be processed 2a of the workpieces 2 and impact generated when the bubbles collapse. A pressure can be applied to the processing region 2b of each processing surface 2a. Therefore, according to the surface treatment method according to the present embodiment, it is possible to improve the processing efficiency by simultaneously performing the surface treatment of the two workpieces 2 by the single injection nozzle 1. Moreover, since the several injection nozzle 1 is not required, it contributes to the reduction of installation cost.

In addition, by increasing the radius r ₂ of the vortex generating jig 8, the flow velocity of the cavitation jet 3 can be greatly reduced in the process in which the cavitation jet 3 flows along the outer peripheral side surface 8 a of the vortex generating jig 8. If the pressure of the liquid increases due to a decrease in the flow velocity of the cavitation jet 3, the cavitation bubbles collapse. By setting the collapse position of the cavitation bubble in the vicinity of each processing surface 2a of each processing object 2, the processing surface 2a of the processing object 2 has a convex curved surface and the radius of curvature r is small. However, sufficient bubble collapse can be generated in the vicinity of the surface 2a to be processed.

(Embodiment 6)
The surface treatment apparatus according to the sixth embodiment shown in FIG. 5 is an apparatus for simultaneously performing the surface treatment of two workpieces 2 as in the fifth embodiment, and the eddy current generating jig 8 shown in the fifth embodiment. The shape of is changed.

  That is, the eddy current generating jig 9 in the surface treatment apparatus according to the present embodiment is made of a metal material such as stainless steel, and has an acute angle isosceles triangular cross-sectional shape. The apex angle a of the eddy current generating jig 9 is smaller than the base angles b and c, and the apex angle a and the base angles b and c are subjected to curved surface processing by chamfering. The apex angle a of the eddy current generating jig 9 is on the jet central axis C, and the base angles b and c are arranged so as to be symmetrical with respect to the jet central axis C.

  The distance from the jet central axis C to the base angle b and the distance from the jet central axis C to the base angle c are both equal to or greater than the radius r of the workpiece 2.

  Other configurations in the surface treatment apparatus according to the present embodiment are the same as those in the fifth embodiment, and thus the description thereof is omitted.

  In the present embodiment, as in the surface treatment method shown in the fifth embodiment, the vortex 4 is formed at two locations above and below the vortex generator 9. That is, the operational effects of the present embodiment are the same as the operational effects of the fifth embodiment.

(Other embodiments)
Although Embodiment 1-6 demonstrated the case where the cross-sectional shape of the to-be-processed object 2 was circular, since the impact pressure generate | occur | produced when the cavitation bubble by the eddy current 4 collapses is very strong, Even when the cross-sectional shape is rectangular or plate-like, surface treatment can be performed efficiently.

  In the first to sixth embodiments, the rod-shaped workpiece 2 whose cross-sectional shape does not change in the longitudinal direction of the workpiece 2 has been described as an object. However, the processing surface of the workpiece is perpendicular to the paper surface. It is also possible to subject the surface treatment to a case where there is a curvature (that is, a rod-like workpiece whose cross-sectional shape changes in the longitudinal direction of the workpiece). In this case, the surfaces of the eddy current generating jigs 5, 7, 8, 9 and the eddy current damming jig 6 that are opposite to the surface to be processed are formed along a curvature perpendicular to the paper surface of the surface to be processed. A jig may be used.

  Moreover, although Embodiment 1-6 demonstrated the surface treatment apparatus in which the injection nozzle 1 was enabled to reciprocate to the longitudinal direction of the to-be-processed object 2, on the contrary, the injection nozzle 1 was fixed. In addition, a surface treatment apparatus in which the workpiece 2, the eddy current generating jigs 5, 7, 8, 9 and the eddy current blocking jig 6 can reciprocate in the longitudinal direction of the workpiece 2 is used. May be.

  In addition, although the example which uses water for a jet is demonstrated in Embodiment 1-6, you may use oil, an emulsion (emulsion), and another liquid, without being limited to this.

Example 1
Using the surface treatment apparatus described in Embodiment 1, surface treatment was performed on the workpiece 2 under the conditions shown in FIG. 6 and the following. In all examples and comparative examples described below, water was used as a cavitation jet.

Processed object 2: Round bar made of aluminum alloy with outer diameter φ6 mm and length 20 mm Eddy current generating jig 50: Round bar made of stainless steel with outer diameter φ6 mm Outer peripheral side surface 50 a of vortex generator 50 from the injection port of injection nozzle 1 Distance to: 70mm
Distance between the outer peripheral side surface 50a of the eddy current generating jig 50 and the surface 2a to be processed 2a: 2mm
The diameter of the injection nozzle 1 is 2 mm.
Pressure of cavitation jet 3: 10 MPa
Cavitation peening treatment time: 15 minutes Rotation of the workpiece 2: None Movement of the injection nozzle 1: None After the surface treatment of the workpiece 2 is finished, the area (processing area) of the erosion region is measured on the surface 2a to be treated. It was measured.

(Example 2)
Using the surface treatment apparatus described in the fifth embodiment, a plurality of workpieces 2 were subjected to surface treatment.

  As shown in FIG. 7, the line connecting the two workpieces 2 and the axis of the workpiece 2 and the axis of the eddy current generating jig 50 is at an angle of 35 ° with respect to the jet central axis C. The conditions other than the arrangement in FIG.

  After the surface treatment of the workpiece 2 was completed, the area of the erosion region (treated area) was measured for the treated surface 2a.

Example 3
Using the surface treatment apparatus described in the first embodiment, the workpiece 2 is rotated around the axis of the workpiece 2 (clockwise in FIG. 8) under the conditions shown in FIG. Surface treatment was applied to the workpiece 2 under the same conditions as in Example 1 except that the workpiece 2 was moved in the longitudinal direction (perpendicular to the paper surface in FIG. 8) and the cavitation peening treatment time was set. .

Rotation speed of workpiece 2: 3 rpm
Movement speed of the injection nozzle 1: 6 mm / min Cavitation peening processing time: Until the surface treatment of the entire surface 2a to be processed is completed The processing time required until the surface treatment of all the surfaces 2a to be processed 2 is completed In addition to the measurement, after the surface treatment was completed, the residual stress of the surface 2a to be treated was measured using an X-ray residual stress measuring device (not shown).

Example 4
Using the surface treatment apparatus described in Embodiment 2, surface treatment was performed on the workpiece 2 under the conditions shown in FIG. 9 and the following.

Processed object 2: Round bar made of an aluminum alloy with an outer diameter of 6 mm and a length of 20 mm. Eddy current blocking jig 60: Flat plate made of stainless steel with a blocking surface 60a having a length of 100 mm. Distance to surface 2a to be processed 2: 70 mm
Distance between the surface 2a to be processed 2 and the damming surface 60a of the eddy current damming jig 60: 2 mm
The diameter of the injection nozzle 1 is 2 mm.
Pressure of cavitation jet 3: 10 MPa
Cavitation peening treatment time: 15 minutes Rotation of the workpiece 2: None Movement of the injection nozzle 1: None After the surface treatment of the workpiece 2 is finished, the area (processing area) of the erosion region is measured on the surface 2a to be treated. It was measured.

(Example 5)
Using the surface treatment apparatus described in the second embodiment, the workpiece 2 is rotated around the axis of the workpiece 2 (clockwise in FIG. 10) under the conditions shown in FIG. Surface treatment was performed on the workpiece 2 under the same conditions as in Example 4 except that the workpiece 2 was moved in the longitudinal direction (in FIG. 10, the direction perpendicular to the paper surface).

Rotation speed of workpiece 2: 3 rpm
The moving speed of the jet nozzle 1 is 6 mm / min. The processing time required until the surface treatment of all the treated surfaces 2a of the workpiece 2 is finished, and after the surface treatment is finished, the X-ray residual stress (not shown) The residual stress of the to-be-processed surface 2a was measured using the measuring apparatus.

(Comparative Example 1)
Using a conventional surface treatment apparatus that does not include a vortex generating jig or a vortex damming jig, surface treatment was performed on the workpiece 2 under the following conditions.

Processed object 2: Round bar made of an aluminum alloy having an outer diameter of φ6 mm and a length of 20 mm Distance from the injection port of the injection nozzle 1 to the surface 2a of the object 2 to be processed: 15 mm
The diameter of the injection nozzle 1 is 0.7 mm.
Pressure of cavitation jet 3: 10 MPa
Cavitation peening treatment time: 15 minutes Rotation of the workpiece 2: None Movement of the injection nozzle 1: None After the surface treatment of the workpiece 2 is finished, the area (processing area) of the erosion region is measured on the surface 2a to be treated. It was measured.

(Comparative Example 2)
The same conditions as in Comparative Example 1 except that the diameter of the injection port of the injection nozzle 1 is φ2 mm and the distance from the injection port of the injection nozzle 1 to the surface 2a to be processed 2 is 70 mm. The surface treatment was performed on the object 2 to be treated. After the surface treatment of the workpiece 2 was completed, the area of the erosion region (treated area) was measured for the treated surface 2a.

(Comparative Example 3)
The workpiece 2 is rotated around the axis of the workpiece 2 under the following conditions, the jet nozzle 1 is moved in the longitudinal direction of the workpiece 2, and the workpiece 2 is ejected from the jet port of the jet nozzle 1. Except for setting the distance to the processing surface 2a and setting the cavitation peening processing time, surface processing was performed on the processing object 2 under the same conditions as in Comparative Example 1.

Distance from the injection port of the injection nozzle 1 to the surface 2a to be processed 2a: 23 mm
Rotation speed of workpiece 2: 3 rpm
Movement speed of spray nozzle 1: 1 mm / min Cavitation peening treatment time: Until the surface treatment of all the treated surfaces 2a is finished The treatment time required until the surface treatment of all the treated surfaces 2a of the workpiece 2 is finished In addition to the measurement, after the surface treatment was completed, the residual stress of the surface 2a to be treated was measured using an X-ray residual stress measuring device (not shown).

(Comparative Example 4)
A comparative example except that the workpiece 2 is rotated around the axis of the workpiece 2 under the following conditions, the injection nozzle 1 is moved in the longitudinal direction of the workpiece 2, and the cavitation peening treatment time is set. 2 was subjected to surface treatment under the same conditions as 2.

Rotation speed of workpiece 2: 3 rpm
Movement speed of the injection nozzle 1: 6 mm / min Cavitation peening processing time: Until the surface treatment of the entire surface 2a to be processed is completed The processing time required until the surface treatment of all the surfaces 2a to be processed 2 is completed In addition to the measurement, after the surface treatment was completed, the residual stress of the surface 2a to be treated was measured using an X-ray residual stress measuring device (not shown).

(Evaluation of processing area)
In Examples 1, 2 and 4, and Comparative Examples 1 and 2, the surface area 2a after the surface treatment is the area of the erosion region (the region where the surface is damaged by the collapse of the cavitation bubbles and becomes tattered). It was measured. The result is shown in FIG. In addition, the vertical axis | shaft of FIG. 11 is described with the index | exponent which set the area (processed area) of the erosion area | region of the comparative example 1 to ten.

  In Comparative Example 1, in order to cause collapse of cavitation bubbles in a narrow region, the cavitation jet 3 jetted from the jet nozzle 1 is directly applied to the workpiece 2 using the jet nozzle 1 having a jet diameter of 0.7 mm. Although it is a case where it collides, naturally the processing area is small. Further, erosion marks were observed only in the vicinity where the cavitation jet 3 collided with the surface 2a of the object 2 to be processed.

  The comparative example 2 is a case where the cavitation jet 3 jetted from the jet nozzle 1 is directly collided with the workpiece 2 using the jet nozzle 1 having a jet diameter of φ2 mm. The erosion traces smaller than the erosion trace of the comparative example 1 were seen in the vicinity which collided with 2 to-be-processed surface 2a. Further, on the upstream side of the upper side surface and the lower side surface of the surface to be processed 2a, erosion marks larger than the erosion marks in the vicinity where the cavitation jet 3 collides with the surface 2a to be processed 2 are processed. It was observed. For this reason, the processing area of the comparative example 2 was larger than the comparative example 1, and became about 5 times the comparative example 1.

  On the other hand, in Example 1, the cavitation jet 3 injected from the injection nozzle 1 does not directly collide with the workpiece 2. Therefore, no erosion marks are seen in the vicinity of the processing surface 2a of the workpiece 2 on the jet central axis C, but on the upstream side of the upper side surface and the upstream side of the lower side surface of the processing surface 2a. Since cavitation bubbles collapsed vigorously due to the influence of the vortex 4 generated by the eddy current generating jig 50, the erosion scar eroded violently in a wider area than the erosion scar on the side surface of the comparative example 2. It was seen. For this reason, the processing area of Example 1 was larger than Comparative Examples 1 and 2, and was about 12 times that of Comparative Example 1.

  In the second embodiment, the cavitation bubbles generated on the downstream side above the eddy current generating jig 50 and the cavitation bubbles generated on the downstream side below the vortex generating jig 50 are treated surfaces 2a of different objects 2 to be processed. In the vicinity of In Example 1, erosion marks were similarly found on the upstream side of the upper side surface and the upstream side surface of the lower side surface in Example 2, but in Example 2, the upper side surface of the processed surface 2a and Erosion marks were observed only on one side of the lower side that is far from the jet central axis C. The processing area of one workpiece 2 in Example 2 was about 7 times that of Comparative Example 1.

  In the fourth embodiment, the eddy current blocking jig 60 disposed on the downstream side of the workpiece 2 is used to block the vortex 4 that is about to flow downstream, and the cavitation bubbles generated by the vortex 4 are removed. This is a case where the material is collapsed in the vicinity of the surface to be processed 2a. In the same manner as in Comparative Example 2, the cavitation bubbles collapse in the vicinity where the cavitation jet 3 collides with the surface 2a to be processed 2 and on the upstream side of the upper side surface and the upstream side surface of the lower side of the surface 2a. Erosion marks that were severely eroded by were seen. Furthermore, in Example 4, erosion marks that were slightly eroded were also observed on the downstream side of the surface to be treated 2a as erosion marks that were not seen in Comparative Examples 1 and 2. For this reason, the processing area of Example 4 was larger than Comparative Examples 1 and 2, and was about 12 times that of Comparative Example 1.

(Evaluation of residual stress)
In Examples 3 and 5 and Comparative Examples 3 and 4, the residual stress of the surface 2a to be processed was measured on the surface 2a after the surface treatment using an X-ray residual stress measuring apparatus. The result is shown in FIG.

  In Comparative Example 3, a compressive residual stress of about 140 MPa, which is the same level as in Examples 3 and 5, occurred over the entire surface 2a. In Comparative Example 3, the diameter of the injection port of the injection nozzle 1 is as small as φ0.7 mm, and the distance from the injection port of the injection nozzle 1 to the surface 2a to be processed 2 is as short as 23 mm. The impact pressure generated at the time of bubble collapse acts intensively on a narrow area of the processing surface 2a. For this reason, since the to-be-processed surface 2a erodes violently, the compressive residual stress is also a large value.

  In Comparative Example 4, the diameter of the injection port of the injection nozzle 1 is larger than that of Comparative Example 3 and is 2 mm, and the distance from the injection port of the injection nozzle 1 to the processing surface 2a of the workpiece 2 is Comparative Example 3. Since the distance is 70 mm, the impact pressure generated at the time of bubble collapse acts on a wide area of the surface 2a to be processed. For this reason, the erosion of the to-be-processed surface 2a is weaker than that of Comparative Example 3, and the compressive residual stress is smaller than that of Comparative Example 3.

  On the other hand, in Example 3, the collapse of the cavitation bubbles occurs actively due to the influence of the vortex flow 4 generated by the eddy current generating jig 50, so that the impact pressure generated when the bubbles collapse is generated in a wide area of the processing surface 2a. Acts violently. For this reason, in Example 3, the compressive residual stress of the to-be-processed surface 2a was large, and became about 150 MPa. That is, the compressive residual stress of Example 3 was about twice the compressive residual stress of Comparative Example 4 using a conventional surface treatment apparatus that does not include the eddy current generating jig 50.

  In the fifth embodiment, the eddy current 4 that tries to flow downstream is blocked by the eddy current blocking jig 60, and the cavitation bubbles generated by the vortex 4 can be actively collapsed in the vicinity of the surface 2 a to be processed. Therefore, the impact pressure generated at the time of bubble collapse acts violently on a wide area of the surface 2a to be processed. For this reason, in Example 5, the compressive residual stress of the to-be-processed surface 2a was large, and became about 150 MPa. That is, the compressive residual stress of Example 5 was about twice the compressive residual stress of Comparative Example 4 using a conventional surface treatment apparatus that does not include the eddy current blocking jig 60.

  In addition, in another Example implemented separately from said Example, it verified about the influence which the difference in the rotation direction of the to-be-processed object 2 has on the value of a compression residual stress, The difference in the rotation direction of the to-be-processed object 2 However, there was no significant difference in compressive residual stress.

(Evaluation of processing time)
In Examples 3 and 5 and Comparative Examples 3 and 4, the treatment time required until the surface treatment was completed over the entire length of the workpiece 2 was measured. The result is shown in FIG.

  In Comparative Example 3, a long processing time of about 40 minutes was required. In Comparative Example 3, the diameter of the injection port of the injection nozzle 1 is as small as φ0.7 mm, and the processing area of the processing surface 2a when the surface treatment of the workpiece 2 is performed without moving the injection nozzle 1 is narrow. It took a long time to complete the surface treatment over the entire length of the workpiece 2.

  The processing time of Comparative Example 4 was about 4 minutes, which was the same as in Examples 3 and 5. In Comparative Example 4, since the diameter of the injection port of the injection nozzle 1 is larger than that of Comparative Example 3 and φ2 mm, the surface 2a to be processed when the surface treatment of the workpiece 2 is performed without moving the injection nozzle 1. The processing area is wider than the processing area of Comparative Example 3. For this reason, the processing time required until the surface treatment is completed over the entire length of the workpiece 2 is shorter than that of the comparative example 3.

  In the comparative example 4, the processing area of the processing surface 2a when the surface processing of the processing object 2 is performed without moving the spray nozzle 1 is the same as the processing area of the comparative example 2 shown in FIG. . In Example 3, the processing area of the processing surface 2a when the surface processing of the processing object 2 is performed without moving the spray nozzle 1 is the same as the processing area of Example 1 shown in FIG. . Therefore, the processing area of Comparative Example 4 is about half or less of the processing area of Example 3. However, there was no significant difference in the processing time between Comparative Example 4 and Example 3.

  In contrast, the processing time of Example 3 was as short as about 4 minutes. As described in the evaluation of the residual stress described above, the residual stress in Example 3 and the residual stress in Comparative Example 3 are close to each other. Therefore, the surface treatment method of Example 3 generates a residual stress equal to or greater than that of Comparative Example 3 on the surface to be treated 2a in a treatment time as short as 1/10 compared with the surface treatment method of Comparative Example 3. Can be made. That is, the surface treatment can be efficiently performed.

  The processing time of Example 5 was as short as about 4 minutes as in Example 3. As described in the evaluation of the residual stress described above, the residual stress in Example 5 and the residual stress in Comparative Example 3 are close to each other. Therefore, the surface treatment method of Example 5 generates a residual stress equivalent to or greater than that of Comparative Example 3 on the surface 2a to be treated in a treatment time as short as 1/10 compared with the surface treatment method of Comparative Example 3. Can be made. That is, the surface treatment can be efficiently performed.

DESCRIPTION OF SYMBOLS 1 ... Injection nozzle 2 ... To-be-processed object 2a ... To-be-processed surface 2b ... Processing area 3 ... Cavitation jet 4 ... Eddy current 5 ... Eddy current generating jig 5a ... Outer peripheral side surface 6 ... Eddy current blocking jig 6a ... Damping surface 7 ... Eddy current Generating jig 7a ... Outer peripheral side 8 ... Eddy current generating jig 8a ... Outer peripheral side 9 ... Eddy current generating jig 9a ... Outer peripheral side 50 ... Eddy current generating jig 50a ... Outer peripheral side 60 ... Eddy current blocking jig 60a ... Damping surface C ... Jet central axis O ... Axle core P ... Collision center Q ... Downstream center

Claims (4)

A method of treating a surface to be treated with an impact pressure generated when a bubble collapses by colliding a cavitation jet against a workpiece having a surface to be processed having a convex curved surface to collapse the cavitation bubble,
The cavitation jet flow is arranged on the central axis of the cavitation jet jetted from the jet nozzle and on the upstream side of the object to be processed, and by flowing the cavitation jet along its own surface. Eddy current generating jig consisting of a solid with eddy current generating function to convert
And the vortex included in the cavitation jet is caused to flow downstream by damming the cavitation jet on its own surface on the central axis of the jet and downstream of the workpiece. Eddy current damming jig consisting of a solid with eddy current damming function to suppress
Using one or both of
The eddy current generation function and / or the eddy current blocking function collects the eddy current in the vicinity of the surface to be processed of the workpiece, and collapses the cavitation bubbles in the vortex near the surface to be processed. A surface treatment method characterized by the above. A plurality of the objects to be processed are disposed on both sides away from the jet central axis,
The surface treatment method according to claim 1, wherein the eddy current is collected in the vicinity of each of the surfaces to be processed of the plurality of objects to be processed by the eddy current generating jig. A device for collapsing a cavitation jet against a workpiece having a surface to be processed having a convex curved surface to collapse a cavitation bubble, and processing the surface to be processed by an impact pressure generated at the time of bubble collapse,
An injection nozzle for injecting the cavitation jet;
The cavitation jet is arranged on the jet central axis of the cavitation jet jetted from the jet nozzle and on the upstream side of the object to be processed, and by flowing the cavitation jet along its own surface, An eddy current generating jig consisting of a solid with a vortex generating function that converts the flow into a vortex;
And the vortex included in the cavitation jet is caused to flow downstream by damming the cavitation jet on its own surface on the central axis of the jet and downstream of the workpiece. Eddy current damming jig consisting of a solid with eddy current damming function to suppress
One or both of
The eddy current generation function and / or the eddy current blocking function collects the eddy current in the vicinity of the surface to be processed of the workpiece, and collapses the cavitation bubbles in the vortex near the surface to be processed. A surface treatment apparatus characterized by the above.   The surface of the eddy current generating jig and / or the eddy current blocking jig facing the surface to be processed is formed along a curvature in an axial direction of the surface to be processed. 3. The surface treatment apparatus according to 3.

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