Cavitation device and cavitation treatment method

Abstract

The invention provides a cavitation treatment device. The cavitation treatment device provides an optimal cavitation effect at an appropriate treatment position. A cavitation treatment device is provided with: a nozzle (2) that ejects a cavitation fluid (C1); a direction switching unit (3) that changes the flow direction of the cavitation fluid (C1) and has a groove (5) that guides the flow direction of the cavitation fluid (C1) and suppresses diffusion of cavitation bubbles (C2) contained in the cavitation fluid (C1); and a workpiece fixing part (6) on which the workpiece (W) is disposed.

Description

Technical Field

[0001] The invention relates to a device and a cavitation treatment method for performing cavitation treatment on the surface of a component. Background Art

[0002] In the past, cavitation treatment was performed on high-function parts such as aircraft parts. By applying compressive residual stress to the surface of various parts and forming a dent shape, friction was relieved while retaining lubricating oil. Cavitation treatment is a general term for surface treatment, shot peening, cleaning, peeling, cutting, deburring, etc.

[0003] However, there are still many unexplained principles regarding cavitation using liquid (eg, water), and it is not easy to establish a method and device for stably controlling cavitation.

[0004] For example, a system is disclosed for surface treatment of the inner surface of a component, comprising: a tank in which the component can be positioned; a fluid in the tank, which can sink the component into the fluid when the component is positioned in the tank; a nozzle, which is immersed in the fluid and generates a cavitation fluid flow toward a first direction; and a deflection tool, which is immersed in the fluid and has a deflection surface for redirecting the cavitation fluid flow from the first direction to a second direction, and the first direction is away from the inner surface of the component and the second direction is toward the inner surface of the component. (For example, Japanese Patent Publication No. 2020-157470, hereinafter referred to as "Patent Document 1"). Summary of the invention

[0005] As shown in Patent Document 1, cavitation treatment can be performed inside a workpiece of a complex shape by changing the flow direction of the cavitation fluid using a deflection tool. However, there is still room for improvement in order to reliably impart cavitation at a target position of a workpiece to be cavitation treated.

[0006] For example, when the cavitation fluid is made to collide directly with the workpiece, or when the cavitation fluid is made to collide directly with the workpiece by simply changing the flow direction of the cavitation fluid, cavitation may be performed not at the target position of the workpiece but around the target position.

[0007] In addition, the cavitation fluid ejected from the nozzle in the liquid contains cavitation bubbles. It is known that the cavitation bubbles are temporarily retained in the liquid. Even if the cavitation fluid is collided with the workpiece in a state where the cavitation bubbles are dispersed, it is impossible to impart the best cavitation effect (residual stress, etc.) to the target position of the workpiece. That is, even if the cavitation fluid is collided with the workpiece in a state where the cavitation bubbles are dispersed, in order to impart the best cavitation effect to the target position of the workpiece, the number of processing times becomes large and a long time is required.

[0008] An object of the present invention is to provide a cavitation treatment device and a cavitation treatment method that can impart an optimal cavitation effect (residual stress, etc.) at an appropriate treatment position.

[0009] The cavitation treatment device of the present invention comprises:

[0010] a nozzle that ejects a cavitation fluid;

[0011] a direction switching portion that changes the flow direction of the cavitation fluid and has a groove portion that guides the flow direction of the cavitation fluid and suppresses diffusion of cavitation bubbles contained in the cavitation fluid; and

[0012] A workpiece fixing portion is provided with a workpiece.

[0013] The cavitation treatment method of the present invention comprises:

[0014] The cavitation fluid C1 is ejected from the nozzle 2,

[0015] The flow direction of the cavitation fluid C1 ejected from the nozzle 2 is guided, and the diffusion of the cavitation bubbles C2 contained in the cavitation fluid C1 in the groove portion 5 is suppressed.

[0016] The cavitation bubbles C2 guided by the groove portion 5 are caused to collide with the workpiece W.

[0017] According to the cavitation treatment device and the cavitation treatment method of the present invention, an optimal cavitation effect (residual stress, etc.) is imparted at an appropriate treatment position. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a side view showing the cavitation treatment device according to the first embodiment.

[0019] Figure 2 This is a perspective view showing a cavitation treatment device according to the first embodiment in a typical situation.

[0020] Figure 3 This is a perspective view of the cavitation treatment device according to the first embodiment showing a state adjusted by the collision distance adjustment unit.

[0021] Figure 4 It is a perspective view showing the groove portion of the first embodiment.

[0022] FIG. 5( a ) is a diagram showing a triangular groove portion, and FIG. 5( b ) is a diagram showing an arc-shaped groove portion.

[0023] Figure 6 It is a perspective view showing the groove portion of Modification Example 1.

[0024] Figure 7It is a perspective view showing the groove portion of Modification Example 2.

[0025] Figure 8 It is a perspective view showing a cavitation treatment device according to a second embodiment.

[0026] Fig. 9 It is a perspective view showing a cavitation treatment device according to a third embodiment.

[0027] Fig. 10A 3 is a graph showing the test results of Comparative Example 1.

[0028] Fig. 10B It is a graph showing the test results of Example 1.

[0029] Fig.11 It is a graph showing the measurement results of the residual stress of Comparative Example 1 and Example 1.

[0030] Explanation of symbols

[0031] 1 Cavitation treatment device

[0032] 2 Nozzles

[0033] 3-direction switching unit

[0034] 4 Secondary direction switching unit

[0035] 5 Slot

[0036] 5a Inclined part

[0037] 6 Workpiece fixing part

[0038] 7 Angle adjustment unit

[0039] 7a Angle adjustment switch

[0040] 8 Collision distance adjustment unit

[0041] 8a Collision distance adjustment switch

[0042] 9 Lifting unit

[0043] 9a Lifting switch

[0044] 9b Lifting support

[0045] 10 Rotating mechanism

[0046] 11 Supporting part

[0047] 12 Control Devices

[0048] C1 Cavitation Fluid

[0049] C2 Cavitation bubbles

[0050] W Workpiece

[0051] T-tank

[0052] W1 Slot width

[0053] H1 Slot height

[0054] WC Diameter of cavitation fluid DETAILED DESCRIPTION

[0055] Embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

[0056] The cavitation treatment device 1 of this embodiment performs cavitation treatment on the surface of high-function components used in the nuclear energy field, general metal components, etc. Figure 1 as well as Figure 2 As shown, the cavitation treatment device 1 includes a nozzle 2, a direction switching portion 3, a workpiece fixing portion 6, and an angle adjustment portion 7. The nozzle 2 sprays the cavitation fluid C1. The direction switching portion 3 changes the flow direction of the cavitation fluid C1. The workpiece fixing portion 6 arranges the workpiece W in the flow direction of the cavitation fluid C1 supplied from the direction switching portion 3. The angle adjustment portion 7 adjusts the angle of the workpiece fixing portion 6. The direction switching portion 3 includes a groove portion 5. The groove portion 5 guides the flow direction of the cavitation fluid C1 and suppresses the diffusion of the cavitation bubbles C2 constituting the cavitation fluid C1.

[0057] The nozzle 2 ejects the cavitation fluid C1 supplied from a high-pressure fluid supply source (not shown).

[0058] The cavitation fluid C1 ejected from the nozzle 2 collides with the surface of the direction switching portion 3 to switch the flow direction of the cavitation fluid C1. The direction switching portion 3 receives the flow of the cavitation fluid C1 at one time. Therefore, in order to prevent the surface of the direction switching portion 3 from being destroyed or damaged by cavitation, the surface of the direction switching portion 3 is preferably made of a material with high strength.

[0059] The groove portion 5 has a shape that guides the flow direction of the cavitation fluid C1 and suppresses the diffusion of the cavitation bubbles C2 constituting the cavitation fluid C1.

[0060] like Figure 4 As shown, the cavitation fluid C1 collides with the grooves 5 disposed on the surface of the direction switching portion 3 , thereby switching the flow direction of the cavitation fluid C1 .

[0061] The shape of the groove 5 is preferably a concavo-convex shape. The groove 5 is concavo-convex, so that the cavitation bubbles C2 can easily enter the concave part, and the cavitation bubbles C2 can be easily formed in a state where it is difficult to diffuse, thereby improving the cavitation effect (residual stress, etc.). In addition, since it is easy to form a state where the cavitation bubbles C2 are difficult to diffuse, the cavitation treatment of the workpiece W can be performed in a shorter time than before.

[0062] The shape, width, depth, number, etc. of the grooves 5 are not limited as long as they function as a flow path for the cavitation fluid C1. For example, a triangular shape as shown in FIG. 5(a) or an arc shape as shown in FIG. 5(b) may be selected as appropriate.

[0063] The groove portion 5 is a flow path that guides the cavitation fluid C1 to the workpiece W. In the case of a linear flow path, the cavitation fluid C1 can be made to collide with the workpiece W directly.

[0064] When a single concave groove or arc groove is formed in the groove portion 5 , by making the groove width relatively wide, the cavitation fluid C1 can collide with the workpiece W as a single flow, thereby achieving a higher cavitation effect locally.

[0065] Specifically, Figure 4 As shown, the groove portion 5 has a groove width W1 and a groove height H1. By making the groove width W1 and the groove height H1 larger than the diameter WC of the cavitation fluid C1, the diffusion of the cavitation bubbles C2 can be suppressed.

[0066] When a plurality of concave grooves or arcuate grooves are formed in parallel in the groove portion 5 , the cavitation fluid C1 can be made to collide with the workpiece W as a plurality of flows, and a higher cavitation effect can be obtained for a wider width.

[0067] Specifically, Figure 6 As shown, a plurality of grooves 5 are formed on the direction switching portion 3. The cavitation fluid C1 ejected from the nozzle 2 is branched to the plurality of grooves 5, and the flow direction of the branched cavitation fluid C1 is guided to each groove 5. In this case, the diameter WC of the cavitation fluid C1 flowing through each groove 5 is branched into diameters WC2 to WC8, and collides with the workpiece W below the groove height H1.

[0068] Furthermore, when a plurality of straight flow paths are formed to merge at a location close to the workpiece W, although the width of the cavitation treatment on the workpiece W becomes narrower, the amount of cavitation bubbles C2 increases, so that a higher cavitation effect can be obtained.

[0069] The groove 5 is a flow path for guiding the cavitation fluid C1 to the workpiece W. However, in order to more easily guide the cavitation fluid C1, the nozzle 2 is preferably tilted. The tilt angle of the nozzle 2 is adjusted within a range of 0 to 180 degrees. By tilting the nozzle 2, the cavitation effect on the groove 5 can be suppressed.

[0070] In addition, in addition to the method of tilting the nozzle 2, Figure 7 As shown, the groove portion 5 has an inclined portion 5 a , whereby the cavitation fluid C1 can flow only in the direction of the workpiece W.

[0071] like Figure 2 and Figure 3As shown, the direction switching portion 3 is provided with a collision distance adjusting portion 8. The collision distance adjusting portion 8 adjusts the collision distance between the cavitation fluid C1 and the workpiece W. The collision distance adjusting portion 8 adjusts the width and length of the direction switching portion 3 in the front-rear and left-right directions. Figure 2 The collision distance adjustment unit 8 of the cavitation treatment device 1 in a normal state is shown. Figure 3 The cavitation treatment device 1 is shown in a state where the width of the collision distance adjustment part 8 is narrowed by adjusting it with the switch 8a for the collision distance adjustment part. As a specific internal structure of the collision distance adjustment part 8, it has a sliding mechanism or a cylinder mechanism. In addition, the switch 8a for the collision distance adjustment part can be manual or automatic. The collision distance adjustment part 8 adjusts the collision distance according to the cavitation treatment conditions. In addition, the direction switching part 3 can also be configured as a unit structure, and a plurality of direction switching parts 3 can be configured. Through the collision distance adjustment part 8, the optimal amount of cavitation bubbles C2 (aggregate) is made to collide with the workpiece W, and cavitation treatment can be performed.

[0072] The workpiece fixing portion 6 fixes the workpiece W. The workpiece fixing portion 6 fixes the end of the workpiece W with a plurality of fasteners such as bolts, or clamps a part of the workpiece W to fix it.

[0073] The angle adjustment part 7 adjusts the inclination angle of the workpiece W. The angle adjustment part 7 is connected to the workpiece fixing part 6. The angle adjustment part 7 is connected to the lower part of the workpiece fixing part 6, for example. The angle adjustment part 7 is adjusted by using the angle adjustment part switch 7a to position at an angle of 0 to 180°, more preferably 45 to 135°. As a specific internal structure of the angle adjustment part 7, it has a sliding mechanism or a cylinder mechanism. In addition, the angle adjustment part switch 7a can be manual or automatic.

[0074] A lifting unit 9 may be disposed below the direction switching unit 3. The lifting unit 9 is adjusted by using a lifting unit adjustment switch 9a, and the lifting support unit 9b is extended and retracted to adjust the height of the direction switching unit 3. Specifically, the lifting unit 9 has a sliding mechanism or a cylinder mechanism. The lifting unit 9 adjusts the height of the direction switching unit 3 according to the cavitation treatment conditions. The lifting unit 9 allows the cavitation bubble C2 to collide with the workpiece at a target position relative to the workpiece W in the up-down direction, thereby enabling cavitation treatment.

[0075] It is also possible to have a secondary direction switching portion 4 that further changes the flow direction of the cavitation fluid C1 switched by the direction switching portion 3. The secondary direction switching portion 4 is, for example, fixed to the workpiece fixing portion 6. The secondary direction switching portion 4 may also have a groove portion similar to the direction switching portion 3. In this case, the groove portion of the secondary direction switching portion 4 may also change the flow direction of the cavitation fluid C1 within the plane.

[0076] The velocity of the cavitation fluid C1 is optimized by adjusting the flow direction of the cavitation fluid C1 in two stages, the direction switching unit 3 and the secondary direction switching unit 4. In addition, the workpiece W with a complex structure can be cavitated, and the target position of the workpiece W and the adjustment of the collision force can be increased.

[0077] The control device 12 may be provided to adjust the amount of cavitation bubbles C2. For example, in a liquid, cavitation bubbles C2 are affected by temperature changes. The control device 12 is, for example, a commercially available temperature adjustment device. The optimum temperature is 40 to 50°C, but the control device 12 adjusts the temperature according to the environment in the liquid or the cavitation effect required for the workpiece.

[0078] like Figure 8 and Fig. 9 As shown, the workpiece fixing portion 6 may also have a rotating mechanism 10 for supporting or rotating the workpiece W. The rotating mechanism 10, for example, has a rotating shaft of an axially symmetrical shape (for example, a cylinder, a round rod, etc.) that can be inserted and fixed in the center of the workpiece W, and the rotating shaft is rotated as a driving source (not shown) is driven. By means of the rotating mechanism 10, for example, when the workpiece W is cylindrical, the cavitation treatment position can be changed sequentially. As a result, it is not necessary to fix the workpiece W each time, and the operation time can be shortened. Figure 8 As shown in FIG. 1 , not only the method of fixing the workpiece W by only using the rotating shaft of the rotating mechanism 10 can be adopted, but also Fig. 9 As shown, a support portion 11 is disposed at the front end of the rotating shaft of the rotating mechanism 10, and the cavitation treatment is performed in a state where both ends of the workpiece W are supported.

[0079] In addition, the rotation axis of the rotating mechanism 10 may be configured to adjust the position relative to the workpiece fixing portion 6 or the workpiece W. For example, by arranging the rotation axis of the rotating mechanism 10 on the upstream side (the direction switching portion 3 side) of the workpiece fixing portion 6, the cavitation fluid C1 in the flow direction guided by the groove portion 5 collides with the workpiece W at a short distance. In addition, by arranging the rotation axis of the rotating mechanism 10 on the downstream side (the side away from the direction switching portion 3) of the workpiece fixing portion 6, the cavitation fluid C1 in the flow direction guided by the groove portion 5 collides with the workpiece W at a long distance. The position of the rotation axis of such a rotating mechanism 10 is appropriately selected according to the relationship with the distance from the nozzle 2 to the direction switching portion 3 and the groove portion 5.

[0080] Next, the cavitation treatment process of this embodiment will be described.

[0081] (First embodiment: one-stage direction switching)

[0082] First, the fixing operation of the workpiece W and the determination of the conditions for the cavitation treatment are performed. First, the length and height of the direction switching portion 3 are adjusted by the collision distance adjustment portion 8 and the lifting portion 9, and the workpiece W is fixed to the workpiece fixing portion 6. Next, the angle of the angle adjustment portion 7 is set to the optimal condition of 0 to 180°, more preferably 45 to 135°, and fixed.

[0083] In addition, before or after the fixing operation, the tank T is filled with liquid (e.g., water). By performing cavitation treatment in the liquid, the cavitation bubbles C2 (aggregates) are stably surrounded in the groove 5. Therefore, the optimal amount of cavitation bubbles C2 is made to collide with the workpiece W, and the best cavitation effect can be obtained.

[0084] Next, the high-pressure water supply source (not shown) is started, the position of the nozzle 2 is fixed, and the cavitation fluid C1 is ejected from the nozzle 2 toward the direction switching portion 3. The ejected cavitation fluid C1 collides with the groove portion 5 of the direction switching portion 3 and is decelerated. The cavitation fluid C1 enters the recessed portion of the groove portion 5, moves toward the workpiece W and collides with it, thereby performing cavitation processing.

[0085] In addition, the cavitation bubbles C2 with high concentration collide with the workpiece W while the cavitation fluid C1 is decelerated. Therefore, the cavitation fluid C1 is prevented from being too fast and cavitation is performed at a portion not to be cavitated, and cavitation can be performed at a target position of the workpiece W.

[0086] (Second embodiment: two-stage direction switching)

[0087] First, the workpiece W is fixed and the conditions for cavitation treatment are determined. Figure 8 As shown, the length and height of the direction switching part 3 or the secondary direction switching part 4 are adjusted by the collision distance adjusting part 8 or the lifting part 9, and the workpiece W is fixed on the workpiece fixing part 6. Next, the angle of the angle adjusting part 7 is set to the optimal condition of 0 to 180°, more preferably 45 to 135°, and fixed. In addition, before or after the fixing operation, the tank T is filled with liquid (for example, water).

[0088] Next, the high-pressure water supply source (not shown) is started, the position of the nozzle 2 is fixed, and the cavitation fluid C1 is ejected from the nozzle 2 toward the direction switching portion 3. The ejected cavitation fluid C1 collides with the groove portion 5 of the direction switching portion 3 and is decelerated. The cavitation fluid C1 enters the recessed portion of the groove portion 5 and collides with the secondary direction switching portion 4, further decelerating. The cavitation fluid C1 travels toward the workpiece W along the surface of the secondary direction switching portion 4 and collides, thereby performing cavitation processing.

[0089] In addition, when the cavitation fluid C1 is decelerated, (aggregates of) cavitation bubbles with high concentration collide with the workpiece W. Therefore, the cavitation fluid C1 is prevented from being too fast and cavitation is performed at a portion not to be cavitated, and cavitation can be performed at a target position of the workpiece W.

[0090] Next, a verification test of the cavitation effect when the cavitation treatment device 1 according to the embodiment is used will be described.

[0091] (Verification Test 1)

[0092] Both tests were performed, a test without using the cavitation treatment device 1 (Comparative Example 1) and a test using the cavitation treatment device 1 (Example 1).

[0093] In Comparative Example 1, the cavitation treatment device 1 was not used, and the cavitation fluid C1 of 40 MPa supplied from a high-pressure water supply source (not shown) was directly collided with the verification workpiece W (aluminum plate) from a nozzle (same as the nozzle 2 of the present embodiment) for 15 seconds.

[0094] In Example 1, the position of the nozzle 2 is fixed by the cavitation treatment device 1, and the cavitation fluid C1 of 40 MPa supplied from the high-pressure water supply source (not shown) is sprayed from the nozzle 2 to the direction switching portion 3. The cavitation fluid C1 passes through the groove portion 5 of the direction switching portion 3 and collides with the verification workpiece W (aluminum plate) for 15 seconds.

[0095] Fig. 10A This is the result of verification test 1 of comparative example 1. Fig. 10B This is the result of the verification test 1 of Example 1. Comparing Comparative Example 1 with Example 1, Example 1 has a larger amount of marks. It can be inferred that this is because the cavitation bubbles C2 (aggregates) in the cavitation fluid C1 remain in a non-diffused state, thereby providing the best cavitation effect.

[0096] (Verification Test 2)

[0097] Only the superficial (appearance) effect can be determined by verification test 1. In verification test 2, the residual stress applied to each workpiece W subjected to the verification tests of comparative example 1 and embodiment 1 was measured using a commercially available residual stress measuring device.

[0098] Fig.11 The results of verification test 2 are shown. The vertical axis represents residual stress, and the horizontal axis represents the depth from the surface of the workpiece W. In addition, the residual stress on the vertical axis acts as a tensile force as the value increases in the positive direction, and acts as a compressive force as the value increases in the negative direction. Untreated is represented by ◇, Comparative Example 1 is represented by □, and Example 1 is represented by ○. When comparing Comparative Example 1 with Example 1, the compressive stress of Example 1 remains deeper.

[0099] According to the results of Verification Test 1 and Verification Test 2, Example 1 obtains a greater cavitation effect.

[0100] As mentioned above, the present invention is not limited to the above-mentioned embodiment, and it is needless to say that the present invention can be appropriately modified within the scope not departing from the gist of the present invention.

Claims

1. A cavitation treatment device, characterized in that: have: a nozzle that ejects a cavitation fluid; a direction switching portion that changes the flow direction of the cavitation fluid and has a groove portion that guides the flow direction of the cavitation fluid and suppresses diffusion of cavitation bubbles contained in the cavitation fluid; as well as A workpiece fixing portion is provided with a workpiece.

2. The cavitation treatment device according to claim 1, characterized in that: The groove width and the groove height of the groove portion are larger than the diameter of the cavitation fluid.

3. The cavitation treatment device according to claim 1, characterized in that: The direction switching portion has a plurality of grooves. The cavitation fluid ejected from the nozzle branches to the plurality of grooves, and the flow direction of the branched cavitation fluid is guided to each of the grooves.

4. The cavitation treatment device according to any one of claims 1 to 3, characterized in that: The groove portion has a concavo-convex shape.

5. The cavitation treatment device according to any one of claims 1 to 4, characterized in that: The direction switching unit includes a collision distance adjusting unit that adjusts a collision distance of the cavitation bubbles to the workpiece.

6. The cavitation treatment device according to any one of claims 1 to 5, characterized in that: The invention also includes an angle adjustment portion for adjusting the angle of the workpiece fixing portion.

7. The cavitation treatment device according to any one of claims 1 to 6, characterized in that: A lifting part for adjusting the height of the direction switching part is provided at a lower part of the direction switching part.

8. The cavitation treatment device according to any one of claims 1 to 7, characterized in that: A secondary direction switching unit is provided for further changing the flow direction of the cavitation fluid switched by the direction switching unit.

9. The cavitation treatment device according to any one of claims 1 to 8, characterized in that: The workpiece fixing portion includes a rotating mechanism for rotating the workpiece.

10. The cavitation treatment device according to any one of claims 1 to 9, characterized in that: A tank is further provided, the tank storing liquid, and at least the nozzle, the direction switching portion, and the workpiece fixing portion are arranged in the stored liquid.

11. The cavitation treatment device according to any one of claims 1 to 10, characterized in that: The invention also comprises a control device for adjusting the amount of the cavitation bubbles.

12. A cavitation treatment method, characterized in that: include: The cavitation fluid is ejected from the nozzle, guiding the flow direction of the cavitation fluid ejected from the nozzle and suppressing the diffusion of cavitation bubbles contained in the cavitation fluid in the groove portion, The cavitation bubbles guided by the groove portion are caused to collide with a workpiece.

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