Cavitation treatment method

Abstract

The objective is to improve the effectiveness of cavitation treatment methods that perform cavitation treatment on the surface of objects in the atmosphere. [Solution] The gear (object) 40 is placed in the atmosphere above the liquid surface 111 of the reservoir 11 containing the abrasive material 12, and a nozzle 20 having a nozzle 21 is placed above the gear 40, and a jet of liquid C1 is sprayed from the nozzle 21 toward the object 40 to perform cavitation treatment on the surface 401 of the gear 40.

Description

Technical Field

[0001] The present invention relates to a cavitation treatment method for performing cavitation treatment on the surface of an object.

Background Art

[0002] Conventionally, in the atmosphere, cavitation treatment has been performed on the surface of a metal object (Japanese Patent No. 2957976). Cavitation treatment is to make a jet of liquid containing cavities (bubbles) collide with an object, and to process the surface of the object by the impact force when the cavities collapse. By cavitation treatment, peening for adding compressive residual stress to the surface of the object, improvement of slidability by forming a dimple shape on the surface of the object, and other effects such as cleaning, peeling, cutting, deburring, etc. can be obtained.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The shape and size of the object to be subjected to cavitation treatment in the atmosphere are various. Depending on the conditions of the object, sufficient effects may not be obtained by the conventional cavitation treatment in some cases. An object of the present invention is to improve the effect of a cavitation treatment method for performing cavitation treatment on the surface of an object in the atmosphere.

Means for Solving the Problems

[0004] A first aspect of the present invention is to place an object in the atmosphere above the liquid level of a storage liquid containing an abrasive, to arrange a nozzle having a nozzle opening above the object, to inject a jet of liquid from the nozzle opening toward the object, and to perform cavitation treatment on the surface of the object,

[0005] which is a cavitation treatment method.

[0005] The objects in question are made of metal. Examples of metals that make up the objects include heat-resistant alloys, aluminum alloys, magnesium alloys, titanium, titanium alloys, iron steel, and corrosion-resistant steel. Examples of objects include machine parts, medical device parts, and medical instruments. Machine parts include gears, pipes, valves, pipe fittings, and aerospace components. Medical instruments include surgical implants. Aerospace components include aircraft engine parts and other aircraft parts, rocket engine parts, spacecraft parts, satellite parts, and rocket piping.

[0006] The abrasive material is abrasive particles. Examples of abrasive materials include ceramics, alumina, garnet, and zirconia. In the tank, the abrasive material may be precipitated in the storage liquid. The abrasive material may be mixed in the storage liquid.

[0007] The height from the top surface of the object to the liquid surface is, for example, 200 mm to 600 mm. When the abrasive material settles in the reservoir, it is desirable that the height of the abrasive layer be approximately uniform within the tank. The height of the abrasive layer is, for example, 20 mm to 50 mm. The height from the liquid surface of the reservoir to the surface of the abrasive layer is, for example, 50 mm to 100 mm. When the height from the liquid surface of the reservoir to the surface of the abrasive layer is 50 mm to 100 mm, when the jet enters the reservoir, the abrasive material is scattered into the tank along with the splash of the reservoir.

[0008] The liquid to be stored is kept in a tank. The liquid to be stored is, for example, water. The liquid to be stored may contain a rust inhibitor.

[0009] The liquid that forms the jet is, for example, water. The liquid may also contain a rust inhibitor.

[0010] The nozzle diameter is, for example, 0.5 mm to 3 mm. The jet pressure is, for example, 10 MPa to 200 MPa.

[0011] The nozzle may be positioned directly above the object. In this case, the jet will be ejected directly downwards from the nozzle. The nozzle may be positioned diagonally above the object. In this case, the jet will be ejected diagonally downwards from the nozzle.

[0012] Cavitation treatment is performed on part or all of the surface of the object. A recess is a part of the object's surface that is lower than its surroundings. The recess may be a groove or a hole.

[0013] When a jet of water is sprayed from above towards an object, the jet strikes the object and then collides with the liquid surface below. The impact of the jet causes splashes of the stored water containing abrasive material to rise. The jet then entrains the abrasive material contained in the splashes. The impact of the abrasive material together with the liquid on the object improves the effectiveness of the cavitation treatment. [Effects of the Invention]

[0014] According to the present invention, the effectiveness of a cavitation treatment method that performs cavitation treatment on the surface of an object in the atmosphere can be improved. [Brief explanation of the drawing]

[0015] [Figure 1] Overall view of the cavitation treatment device [Figure 2] Magnified view of the area where the jet strikes the gear. [Modes for carrying out the invention]

[0016] As shown in Figure 1, the cavitation processing apparatus 100 of this embodiment includes a tank 10, a nozzle 20, a nozzle moving device 22, a drive device 32, and a support part 30. The cavitation processing apparatus 100 performs cavitation processing on a gear (object) 40.

[0017] Tank 10 stores the storage liquid 11 and the abrasive material 12. The storage liquid 11 is, for example, water. The cavitation treatment apparatus 100 may have a liquid circulation device for circulating the storage liquid 11.

[0018] The abrasive 12 precipitates in the storage liquid 11. Desirably, the layer height H1 of the abrasive 12 is substantially uniform within the tank 10. The layer height H1 is, for example, 20 mm to 50 mm. The height H2 from the liquid surface 111 of the storage liquid 11 to the layer surface of the abrasive 12 is, for example, 50 mm to 100 mm. The height H3 from the upper surface of the gear 40 to the liquid surface 111 is, for example, 200 mm to 600 mm.

[0019] The nozzle moving device 22 relatively moves the nozzle 20 with respect to the driving device 32 in the front-rear direction, left-right direction, and vertical direction.

[0020] The nozzle 20 has a nozzle opening 21. The nozzle 20 injects a liquid jet C1 supplied from a high-pressure fluid source (not shown) from the nozzle opening 21. The liquid may be the storage liquid 11. When the liquid is the storage liquid 11, the filtered storage liquid 11 that does not contain the abrasive 12 is injected. The jet C1 contains many cavities. The nozzle 20 injects the jet C1 vertically downward, for example. The jet C1 is a linear rod-shaped jet. The nozzle 20 may be rotated about the injection direction of the jet C1 by the nozzle moving device 22. The nozzle diameter (inner diameter) of the nozzle 20 is, for example, 0.5 mm to 3 mm.

[0021] The driving device 32 is disposed at the central portion in the depth direction of the tank 10. The driving device 32 rotates the gear (object) 40 integrally with the support portion 30 around the rotation shaft 31. The rotation shaft 31 extends in the horizontal direction. The support portion 30 is disposed above the liquid surface 111 of the storage liquid 11. The support portion 30 is a round bar shape extending along the rotation shaft 31. The support portion 30 supports the gear 40.

[0022] As shown in FIG. 2, the gear 40 has a plurality of teeth 41 formed side by side on the circumference. A tooth groove 42 is formed between adjacent teeth 41. The bottom of the tooth groove 42 is the tooth root 43. The tooth groove 42 is a recess of the object, and the tooth root 43 is the bottom of the recess. The gear 40 is, for example, a spur gear, a helical gear, an internal gear, a sawtooth gear, a bevel gear, or a rack. The rack may be regarded as a gear with an infinite radius.

[0023] A control device (not shown) controls the injection pressure, injection flow rate, injection speed of the jet flow C1, the movement of the nozzle 20, and the drive device 32.

[0024] The cavitation treatment method of the present embodiment is as follows. First, the storage liquid 11 is stored in the tank 10. Then, the abrasive 12 is put into the storage liquid 11 and allowed to precipitate. At this time, the nozzle 20 and the support portion 30 are located in the atmosphere above the liquid surface 111 of the storage liquid 11. Next, the gear 40 is fixed to the support portion 30. The gear 40 is fixed in a posture in which its rotation axis 44 is horizontal and coincides with the rotation axis 31 of the drive device 32. Next, the drive device 32 is driven to rotate the support portion 30 and the gear 40. Next, the nozzle 20 is arranged above the gear 40, and the distance between the nozzle 20 and the gear 40 is set to a distance suitable for cavitation treatment. The distance suitable for cavitation treatment is about 50 to 200 times the jet diameter of the nozzle 20. Next, a high-pressure fluid supply source (not shown) is activated to inject the jet flow C1 from the nozzle 20. The jet flow C1 collides with the gear 40, and cavitation treatment is performed on its surface 401. Next, each time the gear 40 makes one rotation, the nozzle 20 is moved a predetermined distance in the direction of the rotation axis 44 of the gear 40. The nozzle 20 may be moved along the rotation axis 44 with a predetermined feed amount per rotation. As a result, the entire surface 401 of the gear 40 is subjected to cavitation treatment.

[0025] The behavior when the jet flow C1 collides with the gear 40 will be described in detail. After colliding with the gear 40, the jet flow C1 further proceeds downward as the post-collision jet flow C2 and collides with the liquid surface 111 of the storage liquid 11. The storage liquid 11 is stirred by the post-collision jet flow C2, and the abrasive 12 is lifted up into the storage liquid 11. Further, due to the impact at the time of collision, the storage liquid 11 containing the abrasive 12 from the liquid surface 111 scatters as droplets 13. Then, as shown in FIG. 2, the droplets 13 are卷入 into the jet flow C1. The abrasive 12 contained in the droplets 13 collides with the surface 401 of the gear 40 including the tooth bottom 43 together with the jet flow C1.

[0026] The surface 401 of the gear 40 is subjected to impact forces from the collision of the abrasive material 12 and impact forces from the collapse of cavities contained in the jet C1. These forces impart compressive residual stress to the surface 401 of the gear 40, and dimples are formed on the surface 401 of the gear 40. As the jet C1 incorporates the droplets 13, the abrasive material 12 is included in the jet C1, improving the effectiveness of the cavitation treatment.

[0027] The effect of the cavitation treatment method of this embodiment varies depending on various parameters such as the amount of abrasive material 12 contained in the reservoir 11, the layer height H1 of the abrasive material 12, the height H2 from the liquid surface 111 to the surface of the abrasive material 12 layer, the height H3 from the top surface of the gear 40 to the liquid surface 111, and the distance between the gear 40 and the nozzle 20. Each parameter may be set according to the desired treatment effect. The treatment effect may also be adjusted by placing a shield between the gear 40 and the liquid surface 111 to block some of the splashes 13.

[0028] The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. All technical matters included in the technical concept described in the claims are covered by the present invention. The embodiments described above are preferred examples, but those skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents disclosed herein, and these are included in the technical scope described in the appended claims. [Explanation of symbols]

[0029] 11. Storage liquid 111 Liquid level 12 Abrasive material 20 nozzles 21 spout 40 Gears (objects) 401 Surface C1 jet

Claims

1. The object is placed in the atmosphere above the liquid surface of the reservoir containing the abrasive material. A nozzle having a spray opening is positioned above the object, A jet of liquid is sprayed from the nozzle toward the object, and cavitation treatment is performed on the surface of the object. Cavitation treatment method.

2. The aforementioned jet is a straight, rod-shaped jet. The cavitation treatment method according to claim 1.

3. The jet is the jet of the stored liquid. The cavitation treatment method according to claim 1 or 2.

4. The jet strikes the liquid surface, causing the reservoir containing the abrasive to scatter, and the scattered reservoir is drawn into the jet and strikes the surface. A cavitation treatment method according to any one of claims 1 to 3.

5. The abrasive material is settled in the reservoir. A cavitation treatment method according to any one of claims 1 to 4.

6. The nozzle ejects the jet in a vertically downward direction. A cavitation treatment method according to any one of claims 1 to 5.

7. The jet is ejected while rotating or moving the nozzle. A cavitation treatment method according to any one of claims 1 to 6.

8. The jet is injected while the object is rotated or moved. A cavitation treatment method according to any one of claims 1 to 7.

9. The object has a recess, The jet is made to collide with the bottom of the recess. A cavitation treatment method according to any one of claims 1 to 8.

10. The object is a gear, the recess is the tooth groove of the gear, and the bottom is the tooth root of the gear. The cavitation treatment method according to claim 9.

Images