Cavitation processing method and cavitation processing device

Abstract

To provide a cavitation processing method for performing cavitation processing on a bottom of a groove part of an object.SOLUTION: A cavitation processing method includes: immersing in a process liquid 11, a nozzle 23 which jets a jet flow C1 of the process liquid 11 with cavitation, a spur gear 50a including a tooth space 53 extending to the left and right when viewed from the nozzle 23 and having a front edge part 56 and a rear edge part 57, and a guide part 30 having a rectification part 32 to make the jet flow C1 flow in the front-back direction, and a block part 33 to block the front end of the rectification part 32; bringing the block part 33 closer to the front edge part 56; jetting the jet flow C1 from the nozzle 23; introducing the jet flow C1 from the back side to the rectification part 32; and making the jet flow C1 collide with the block part 33 to change the direction of flow of the jet flow C1, causing the jet flow C1 to collide with a tooth bottom 54 of the tooth space 53.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Conventionally, cavitation treatment has been performed on metallic objects (Patent Publication No. 6872929). Cavitation treatment involves colliding a jet of fluid containing cavities (air bubbles) with the object, and treating the surface of the object with the impact force generated when the cavities collapse. Cavitation treatment can impart compressive residual stress to the surface of the object. Summary of the Invention [Problem to be solved by the invention]

[0003] The objects to be treated by cavitation come in a variety of shapes and sizes. To perform appropriate cavitation treatment, it is necessary to collide the jet with the surface of the object in an appropriate manner according to the conditions of the object. An object of the present invention is to provide a cavitation treatment method for performing cavitation treatment on the bottom of a groove in an object. [Means for solving the problem]

[0004] Representative of the present invention, a nozzle for ejecting a jet of a processing liquid accompanied by cavitation; an object including a groove portion extending left and right as viewed from the nozzle and having edges at the front and rear; and a guide portion including a flow straightening portion for directing the jet in the front and rear directions and a blocking portion for blocking a front end of the flow straightening portion, the guide portion being immersed in the processing liquid; bringing the closure portion into proximity with the front edge; The jet is ejected from the nozzle; The jet flow is introduced into the straightening section from the rear side, and the jet flow is caused to collide with the blocking section, thereby changing the flow direction of the jet flow and causing the jet flow to collide with the bottom of the groove section. A cavitation treatment method.

[0005] During cavitation processing, the object, the nozzle, and the guide are all immersed in a processing liquid stored in a tank. In the processing liquid, a jet of the processing liquid is sprayed from the nozzle toward the guide. The processing liquid is, for example, water. The processing liquid may be water mixed with an abrasive. The processing liquid stored in the tank may be mixed with an abrasive to make it turbid.

[0006] The object is made of a metal. Examples of metals that make up the object include heat resistant alloys, aluminum alloys, magnesium alloys, titanium, titanium alloys, and steel. Examples of the object are machine parts, medical equipment parts, and medical instruments. Examples of machine parts include gears, piping, valves, piping fittings, and aerospace parts. Examples of medical instruments include surgical implants. Examples of aerospace parts include aircraft engine parts and other aircraft parts, rocket engine parts, spacecraft parts, satellite parts, and rocket piping. The object may be manufactured by additive manufacturing.

[0007] The groove of the object extends, for example, from the left end to the right end of one surface of the object, and opens at both ends on the left and right end surface sides. The groove may extend linearly. The groove may extend in a curved manner. The cross-sectional shape of the groove may be, for example, U-shaped or V-shaped. The cross-sectional shape of the groove may have a constant width from the bottom to the opening. The cross-sectional shape of the groove may change in width from the bottom to the opening. The cross-sectional shape of the groove may be constant along the direction in which the groove extends. The cross-sectional shape of the groove may change along the direction in which the groove extends. The object may have one groove. The object may have multiple grooves.

[0008] If the object is a gear, it may be a spur gear, helical gear, internal gear, double helical gear, bevel gear, etc., whose teeth (tooth spaces) are arranged on a circumference. Also, if the object is a gear, it may be a rack, whose teeth (tooth spaces) are arranged on a straight line. A rack can be considered as a gear with an infinite radius.

[0009] The rectifying portion of the guide portion is, for example, a groove extending forward and backward. The rectifying portion is, for example, a groove extending from the rear end to the front end of one surface of the guide portion, and opens at both ends on the front and rear end faces. The rectifying portion may extend linearly. The rectifying portion may extend while bending. When the rectifying portion is a groove, the cross-sectional shape of the rectifying portion is, for example, U-shaped or V-shaped. The cross-sectional shape of the rectifying portion may have a constant width from the bottom to the opening. The cross-sectional shape of the rectifying portion may change in width from the bottom to the opening. The cross-sectional shape of the rectifying portion may be constant along the direction in which the rectifying portion extends. The cross-sectional shape of the rectifying portion may change along the direction in which the rectifying portion extends. The rectifying portion may be made of one groove. The rectifying portion may be made of multiple grooves.

[0010] The blocking portion of the guide portion is, for example, a wall provided at the front end of the straightening portion. The blocking portion may protrude further toward the object than the straightening portion. The blocking portion may be a portion integral with a portion that blocks the front end of the straightening portion that protrudes toward the object. The blocking portion may have a member separate from the portion that blocks the front end of the clean flow portion, and this separate member may protrude toward the object.

[0011] The nozzle has an orifice diameter of, for example, 0.5 mm to 3 mm, and the jet pressure of the jet is, for example, 10 MPa to 200 MPa. The inclination angle of the jet direction may be less than 45 degrees.

[0012] The left-right position of the object may be fixed and the nozzle may be moved left-right.The left-right position of the nozzle may be fixed and the object may be moved left-right.

[0013] If the object is a gear with teeth (tooth spaces) arranged circumferentially, the gear may be rotated about its central axis to move the tooth spaces back and forth. When the object is a gear (rack) whose teeth (tooth spaces) are aligned in a straight line, the gear may be translated forward and backward in order to move the tooth spaces forward and backward. When the target object, that is, a gear, is rotated or moved, the rotation or movement of the gear and the left-right movement of the nozzle or the gear may be synchronized. For example, the nozzle or the gear may be moved left-right every time the gear rotates once. Effect of the Invention

[0014] According to the cavitation treatment method of the present invention, the cavitation treatment device can perform cavitation treatment on the bottom of the groove of the object. [Brief description of the drawings]

[0015] [Figure 1] Cavitation treatment device of the first embodiment [Diagram 2] An enlarged view of a guide portion and a spur gear of the first embodiment. [Diagram 3] Cross-sectional view of line III-III in Figure 2 [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3, illustrating the flow of a jet in the first embodiment. [Diagram 5] FIG. 1 is a plan view illustrating a jet flow in the first embodiment; [Figure 6] An enlarged view of a guide portion and a rack in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] First Embodiment 1, the cavitation treatment device 100 of the present embodiment includes a tank 10, an ejection unit 20, a guide unit 30, a holding unit 40, and a high-pressure fluid supply source 60. The cavitation treatment device 100 performs cavitation treatment on a spur gear (target object) 50a.

[0017] As described below, the ejection unit 20 has a nozzle 23, and front, rear, left and right are defined based on the direction as seen from the nozzle 23. However, the direction away from the nozzle 23 is the forward direction, and the direction approaching the nozzle 23 is the rear direction. In this embodiment, the front, rear and left and right directions are all horizontal directions. That is, in Fig. 1, the right side is the forward direction, the left side is the rear direction, the back side of the paper is the left direction, and the front side of the paper is the right direction. The front, rear and left and right directions do not have to be horizontal directions.

[0018] The spur gear 50a, which is the object, is made of metal. As shown in FIG. 2, the spur gear 50a has a plurality of teeth 51 arranged side by side. The teeth 51 are arranged on a circumference and each protrude toward the outer periphery. The teeth 51 are tapered toward the tip, and the tip is a flat tooth tip surface 52. A tooth groove 53 is formed between adjacent teeth 51. The tooth groove 53 is shaped so that the groove width becomes wider toward the opening side. The bottom of the tooth groove 53 is the tooth bottom 54. The tooth bottom 54 is a surface that connects the roots of the teeth 51 adjacent to both sides. The tooth bottom 54 is a curved surface that is concave toward the opening side of the tooth groove 53. The tooth groove 53 is the groove portion of the object, and the tooth bottom 54 is the bottom of the groove portion. This tooth bottom 54 is the target part of the cavitation treatment.

[0019] As shown in Figs. 1 and 5, the spur gear 50a is arranged with its central axis 55 extending in the left-right direction. As shown in Fig. 2, when the lower part of the spur gear 50a is looked at, the teeth 51 extending left-right are arranged in a front-rear direction. Then, between the front and rear teeth 51, tooth gaps 53 extending left-right are formed. The tooth gaps 53 are open toward the bottom. In a certain tooth gap 53, the rear side edge of the tooth tip surface 52 of the front tooth 51 is a front edge portion 56 that is the front edge portion of the tooth gap 53. In a certain tooth gap 53, the front side edge of the tooth tip surface 52 of the rear tooth 51 is a rear edge portion 57 that is the rear edge portion of the tooth gap 53.

[0020] 1, the tank 10 stores a processing liquid 11. The processing liquid 11 is, for example, water. The tank 10 may include a device for circulating the stored processing liquid 11.

[0021] As shown in FIG. 1, the ejection unit 20 has a supply pipe 21, an outlet pipe 22, and a nozzle . The supply pipe 21 is, for example, a straight pipe extending in the vertical direction. The processing liquid 11 supplied from a high-pressure fluid supply source 60 passes through the inside of the supply pipe 21. The high-pressure fluid supply source 60 may be, for example, a pump. The outlet pipe 22 is connected to the lower end of the supply pipe 21. The angle of the outlet pipe 22 is variable with respect to the supply pipe 21. The direction of the tip of the outlet pipe 22 can be adjusted within a range of at least 0 degrees to 90 degrees (vertically downward) with the front-to-rear direction as the reference. The nozzle 23 is connected to the tip of the outlet pipe 22. The nozzle 23 sprays a jet C1 of the processing liquid 11. The spray direction of the jet C1 changes by changing the direction of the outlet pipe 22. The processing liquid 11 is supplied to the nozzle 23 from the high-pressure fluid supply source 60 through the supply pipe 21 and the outlet pipe 22. The jet C1 contains many cavities. The spray unit 20 can move in three axial directions: the horizontal direction (front-back and left-right directions) and the up-down direction. The spray speed (pressure) and spray angle of the jet C1 and the movement of the spray unit 20 in the three axial directions are controlled by a control device (not shown). The nozzle 23 has an orifice diameter (inner diameter) of, for example, 0.5 mm to 3 mm.

[0022] As shown in FIG. 1, the guide portion 30 has a base portion 31 , a flow straightening portion 32 , and a closing portion 33 . The base portion 31 is a rectangular parallelepiped block that is long in the front-rear direction. As shown in Fig. 3, the width of the base portion 31 in the left-right direction may be greater than the width of the spur gear 50a in the left-right direction. As shown in FIG. 3, the rectifying portion 32 has a plurality of protrusions 321 (six in the illustrated example) formed on the upper surface of the base portion 31, and a plurality of rectifying grooves 322 (five in the illustrated example) formed between adjacent protrusions 321. The protrusions 321 extend in the front-rear direction and are lined up on the left and right. The protrusions 321 extend from the rear end to the front end of the base portion 31. The protrusions 321 have a shape that tapers toward the upper side. The rectifying grooves 322 extend in the front-rear direction and are lined up on the left and right with the protrusions 321 in between. The rectifying grooves 322 extend from the rear end to the front end of the base portion 31 and open to the end face sides at both ends. The rectifying grooves 322 have a shape in which the groove width becomes wider toward the upper side. The width and depth of the rectifying grooves 322 are approximately the same as the width and depth of the tooth grooves 53 of the spur gear 50a. The blocking portion 33 has a rectangular plate-like wall portion 331. The wall portion 331 is attached to the front end surface of the base portion 31, and serves as a wall to block the front end of the flow straightening groove 322. The rear side surface of the wall portion 331 is a vertical surface. The upper end of the front side surface of the wall portion 331 may be inclined with respect to the vertical surface. In other words, the upper end of the wall portion 331 has a shape that tapers toward the upper side. An upper edge portion 332, which is the upper edge portion of the wall portion 331, extends in the left-right direction. The upper edge portion 332 protrudes upward beyond the upper end of the protrusion portion 321 of the flow straightening portion 32. The protruding height of the upper edge portion 332 based on the upper end of the protrusion portion 321 may be shorter than the depth of the flow straightening groove 322. The rear side surface of the wall portion 331 may be inclined with respect to the vertical surface.

[0023] As shown in Fig. 1, the holding unit 40 holds a spur gear 50a. The holding unit 40 has a rotation shaft 41 extending in the left-right direction. The holding unit 40 has a rotation device (not shown) formed of a motor or the like, and is capable of rotating the rotation shaft 41. The rotational movement of the rotation shaft 41 is controlled by a control device (not shown). The spur gear 50a is attached to the rotation shaft 41. The spur gear 50a rotates around a central axis 55 together with the rotation shaft 41.

[0024] As shown in FIG. 1 and FIG. 2, the spray unit 20, the guide unit 30, the holding unit 40 and the spur gear 50a are disposed in the tank 10 and immersed in the processing liquid 11. The guide unit 30 is disposed in front of and below the nozzle 23 of the spray unit 20. The nozzle 23 is oriented so that the jet C1 is sprayed toward the guide unit 30. That is, the spray direction of the jet C1 faces forward and is inclined downward with respect to the front-rear direction. The inclination angle θ of the spray direction with respect to the front-rear direction is, for example, 15 degrees or more and 45 degrees or less. The holding unit 40 is disposed to the left of the guide unit 30. The holding unit 40 holds the spur gear 50a on its right side. The spur gear 50a is disposed above the guide unit 30. The left-right center of the guide unit 30 and the left-right center of the spur gear 50a substantially coincide with each other. The height position of the guide portion 30 is a position where an upper edge portion 332 of the wall portion 331 of the closing portion 33 is spaced from a tooth tip circle 501 of the spur gear 50a by a small gap. The tooth tip circle 501 is a path of the tip of the tooth 51 when the spur gear 50a rotates. The distance between the upper edge portion 332 and the tooth tip circle 501 is, for example, 1 mm or less. Note that the height position of the closing portion 33 with respect to the base portion 31 may be adjustable so as to accommodate cases where the diameter or module of the target spur gear is different. Also, the height position of the guide portion 30 with respect to the holding portion 40 may be adjustable.

[0025] The cavitation treatment device 100 configured in this manner can inject a jet C1 onto the spur gear 50a. In this embodiment, the tooth bottoms 54 of all tooth grooves 53 of the spur gear 50a are the regions where the cavitation treatment is performed. In other words, the tooth bottoms 54 of all tooth grooves 53 of the spur gear 50a are the regions where it is desired to impart the effect of the cavitation treatment.

[0026] In this cavitation treatment device 100, as shown in FIG. 2, the upper edge 332 of the wall portion 331 is in close proximity to the front edge 56 of one tooth groove 53 of the spur gear 50a. That is, the tooth groove 53 and the front end of the flow straightening groove 322 face each other. Also, as shown in FIG. 5, the left-right center of the nozzle 23 and the left-right center of the guide portion 30 are aligned. When the high-pressure fluid supply source 60 is started, a jet C1 is jetted from the nozzle 23. As shown in FIG. 4 and FIG. 5, the jet C1 is introduced into the flow straightening portion 32 of the guide portion 30 from above on the rear side while diffusing up, down, left and right (C11). The jet C1 is dispersed into a plurality (five) of flow straightening grooves 322 and flows inside the flow straightening grooves 322 toward the front side (C12). The front end of the flow straightening groove 322 is closed by the wall portion 331 and opens upward. Therefore, the jet C1 collides with the wall portion 331 of the blocking portion 33 at the front end of the flow straightening groove 322. Then, the jet C1 changes its flow direction and flows upward (C13). As described above, the tooth groove 53 and the front end portion of the flow straightening groove 322 face each other, so the jet C1 enters the tooth groove 53 and collides with the tooth bottom 54, which is the innermost portion of the tooth groove 53. Then, a cavitation process is performed on the tooth bottom 54.

[0027] In this cavitation process, in order to process the tooth bottoms 54 of all the tooth grooves 53 arranged on the circumference, the spur gear 50a is rotated. As described above, in this cavitation process, the tooth bottoms 54 of the tooth grooves 53 facing the front end of the flow straightening groove 322 are processed. For example, as shown in Figs. 1 and 2, when the spur gear 50a is rotated clockwise, the tooth grooves 53 arranged in the front and rear directions substantially move backward in the lower part of the spur gear 50a. Therefore, the tooth grooves 53 facing the front end of the flow straightening groove 322 are sequentially replaced, and the jet C1 collides with the tooth bottoms 54 of the tooth grooves 53 arranged in the front and rear directions sequentially. As a result, the cavitation process is sequentially performed on the tooth bottoms 54 of the tooth grooves 53 arranged in the front and rear directions. The spur gear 50a may be rotated continuously. The spur gear 50a may be rotated intermittently. For example, the spur gear 50a may be rotated by an angle corresponding to one tooth 51 at a time.

[0028] In the cavitation treatment, the strength of the cavitation treatment changes according to the distance from the nozzle 23 as the cavities grow and collapse in the jet C1. The strength of the cavitation treatment is, for example, the strength of the compressive residual stress imparted, and the density and depth of the dimples formed on the surface. Therefore, when the cavitation treatment is performed, the strongest treatment is performed at the point where the distance from the nozzle 23 is the most suitable, and the degree of the treatment becomes weaker as the distance from that point increases. The distance suitable for the cavitation treatment is, for example, about 40 to 100 times the nozzle diameter of the nozzle 23. Therefore, if the nozzle diameter of the nozzle 23 is 1 mm, it is desirable to set the distance between the nozzle 23 and the tooth bottom 54 of the spur gear 50a to 40 mm to 100 mm. This distance is the distance that the jet C1 actually passes through. That is, as shown by dashed arrows C11 to C13 in FIG. 4, it is the distance from the nozzle 23, through the straightening groove 322, colliding with the wall portion 331 and changing direction, to the tooth bottom 54.

[0029] During this cavitation process, the nozzle 23 (the jetting portion 20) may be moved left and right. The strongest cavitation process is performed on the central axis of the jet C1, and the degree of the process weakens as it moves left and right away from the central axis. Therefore, when the width of the spur gear 50a in the left and right direction is wider than a predetermined width, the cavitation process is not performed sufficiently in the tooth bottom 54 at the places far from the central axis of the jet C1 to the left and right. In this case, as shown in FIG. 5, by moving the nozzle 23 left and right, the central axis of the jet C1 also moves, and the cavitation process is performed on the entire tooth bottom 54 from left to right. The nozzle 23 may be moved continuously. The nozzle 23 may be moved intermittently. For example, the nozzle 23 may be moved so that its left and right position coincides with each straightening groove 322. The spur gear 50a (the holding portion 40) may be moved left and right while the nozzle 23 is fixed. That is, the left-right positions of the nozzle 23 and the spur gear 50a may be changed relatively.

[0030] The steps of the cavitation treatment method of this embodiment performed by the cavitation treatment device 100 are as follows. First, the processing liquid 11 is stored in the tank 10. The amount of the processing liquid 11 stored is an amount that can immerse the spur gear 50a to a sufficient depth. The sufficient depth is, for example, 300 mm to 500 mm. At this time, the spray unit 20, the guide unit 30, and the holder 40 are positioned above the liquid surface of the processing liquid 11. Next, the spur gear 50a is fixed to the holder 40. The spur gear 50a is held in a position in which the direction in which the central axis 55 extends is the left-right direction. Next, the relative positions of the ejection part 20, the guide part 30, and the spur gear 50a are set. That is, the direction of the nozzle 23 of the ejection part 20, the distance between the nozzle 23 and the spur gear 50a, the distance between the closing part 33 of the guide part 30 and the spur gear 50a, etc. are appropriately set. Next, the spray unit 20, the guide unit 30 and the holder 40 (spur gear 50a) are moved downward and immersed in the treatment liquid 11 stored in the tank 10. Next, the high-pressure fluid supply source 60 is started to eject a jet C1 from the nozzle 23. The jet C1 passes through the guide portion 30 and reaches the tooth bottom 54 of the tooth groove 53 of the spur gear 50a, where it performs a cavitation process. Next, the spur gear 50a is rotated, and the nozzle 23 is moved left and right as necessary.

[0031] In this manner, the jet C1 is sprayed from the nozzle 23, the spur gear 50a is rotated, and the nozzle 23 is moved as necessary, thereby performing cavitation treatment on the tooth bottoms 54 of the tooth grooves 53 of the spur gear 50a. By making the jet C1 flow inside the straightening grooves 322 of the guide section 30, the jet C1 can be made to collide with the tooth bottoms 54 of the treatment target area without being dispersed to the surroundings.

[0032] The order of the steps of the cavitation treatment method of this embodiment is not limited to the above order. For example, the injection unit 20, the guide unit 30, and the holding unit 40 may be installed in the tank 10 from the beginning. In this case, the treatment liquid 11 may be stored in the tank 10 after the spur gear 50a is fixed to the holding unit 40 and the relative positions of the injection unit 20, the guide unit 30, and the spur gear 50a are set. The spur gear 50a may be rotated from the beginning of the cavitation treatment. The nozzle 23 may be moved left and right from the beginning of the cavitation treatment. The rotation of the spur gear 50a and the movement of the nozzle 23 may be performed simultaneously.

[0033] The shape of the spur gear 50a described above is one example. The cavitation treatment method of this embodiment can also be applied to spur gears whose teeth 51, tooth grooves 53, and tooth bottoms 54 have shapes different from those of the above example. The cavitation treatment method of this embodiment can also be applied to gears other than spur gears. Furthermore, the cavitation treatment method of this embodiment can also be applied to objects having grooves other than gears.

[0034] <Second embodiment> 6, in this embodiment, the object of the cavitation treatment is a rack 50b. The cavitation treatment device 100 used in this embodiment is substantially the same as the device in the first embodiment, except for the holding unit 40.

[0035] The rack 50b, which is the object of this embodiment, can be regarded as a gear with an infinite radius. The rack 50b is made of metal. The rack 50b has a plurality of teeth 51 formed side by side. The teeth 51 are arranged in a straight line. The teeth 51 are tapered toward the tip, and the tip is a flat tooth tip surface 52. A tooth groove 53 is formed between adjacent teeth 51. The tooth groove 53 is shaped so that the groove width becomes wider toward the opening side. The bottom of the tooth groove 53 is the tooth bottom 54. The tooth bottom 54 is a surface that connects the roots of the teeth 51 adjacent to both sides. The tooth bottom 54 is a curved surface that is concave toward the opening side of the tooth groove 53. The tooth groove 53 is the groove portion of the object, and the tooth bottom 54 is the bottom of the groove portion. This tooth bottom 54 is the target part of the cavitation treatment.

[0036] The rack 50b is arranged with the teeth 51 extending left and right aligned front and rear and protruding downward. Tooth gaps 53 extending left and right are formed between the front and rear teeth 51. The tooth gaps 53 open downward. In a certain tooth gap 53, the rear side edge of the tooth tip surface 52 of the front tooth 51 is a front edge portion 56 that is the front edge portion of the tooth gap 53. In a certain tooth gap 53, the front side edge of the tooth tip surface 52 of the rear tooth 51 is a rear edge portion 57 that is the rear edge portion of the tooth gap 53.

[0037] The holding unit 40 of the cavitation treatment device 100 used in this embodiment has a holding table 42. The holding table 42 fixes the rack 50b with fasteners such as bolts and clamps, or clamps and fixes the rack 50b. The holding table 42 is movable back and forth while holding the rack 50b.

[0038] The holder 42 and the rack 50b may be inclined so that the front side is lowered. At this time, the holder 42 may move in the inclined direction of the holder 42. The holder 42 may also move back and forth.

[0039] In this embodiment, the tooth bottoms 54 of all the tooth grooves 53 of the rack 50b are the areas where the cavitation treatment is performed.

[0040] The steps of the cavitation processing method of this embodiment are substantially the same as those of the cavitation processing method of the first embodiment, except that the rack 50b (holding table 42) is moved back and forth.

[0041] In this cavitation process, in order to process the tooth bottoms 54 of all the tooth grooves 53 arranged in a straight line, the rack 50b (holding table 42) is moved back and forth. For example, as shown in FIG. 6, when the rack 50b is moved backward, the tooth grooves 53 arranged in the front and rear are moved backward. Therefore, the tooth grooves 53 facing the front end of the straightening groove 322 are sequentially replaced, and the jet C1 collides with the tooth bottoms 54 of the tooth grooves 53 arranged in the front and rear sequentially. As a result, the cavitation process is sequentially performed on the tooth bottoms 54 of the tooth grooves 53 arranged in the front and rear sequentially. The rack 50b may be moved continuously. The rack 50b may be moved intermittently. For example, the rack 50b may be moved by a distance corresponding to one tooth 51 at a time.

[0042] In this manner, the jet flow C1 is ejected from the nozzle 23, the rack 50b is moved, and the nozzle 23 is also moved as necessary, whereby a cavitation process is performed on the tooth bottoms 54 of the tooth grooves 53 of the rack 50b.

[0043] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention, and all technical matters included in the technical ideas described in the claims are the subject of the present invention. The above-described embodiment shows a preferred example, but a person skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents disclosed in this specification, and these are included in the technical scope described in the attached claims. [Explanation of symbols]

[0044] 11 Processing solution 23 Nozzle 30 Information Department 32 Rectifier 33 Occlusion 50a Spur gear (object) 50b Rack (Object) 53 Tooth groove (groove) 54 Tooth bottom (bottom) 56 Front edge (edge) 57 Trailing edge (edge) C1 Jet

Claims

1. a nozzle for ejecting a jet of a processing liquid accompanied by cavitation; an object including a groove portion extending left and right as viewed from the nozzle and having edges at the front and rear; and a guide portion including a flow straightening portion for directing the jet in the front and rear directions and a blocking portion for blocking a front end of the flow straightening portion, the guide portion being immersed in the processing liquid; bringing the closure portion into proximity with the front edge; The jet is ejected from the nozzle; The jet flow is introduced into the straightening section from the rear side, and the jet flow is caused to collide with the blocking section, thereby changing the flow direction of the jet flow and causing the jet flow to collide with the bottom of the groove section. Cavitation treatment method.

2. Relatively changing the left-right positions of the nozzle and the object; The method for treating cavitation according to claim 1.

3. The jet direction of the jet is inclined with respect to the front-rear direction. The cavitation treatment method according to claim 1 or 2.

4. The inclination angle of the jetting direction with respect to the front-rear direction is 15 degrees or more and 45 degrees or less. The method for treating cavitation according to claim 3.

5. The object is a gear, the groove portion is a tooth groove of the gear, and the bottom portion is a tooth bottom of the gear. A cavitation treatment method according to any one of claims 1 to 4.

6. Rotating or moving the gear so that the tooth space moves back and forth; The jet is caused to collide with the tooth bottoms of the tooth grooves arranged in front and rear in sequence. The method for treating cavitation according to claim 5.

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