JP7565095B2 - Nozzle body - Google Patents

Description

The present invention relates to a nozzle body that sprays abrasives against a workpiece, and in particular to a nozzle body for wet blasting that uses a mixture of slurry and air as the abrasives.

Conventionally, a wet blasting method has been used in which a slurry made by mixing liquid and abrasive grains is prepared, and this slurry is sprayed onto the workpiece using compressed air to treat the surface of the workpiece. This wet blasting method is also called wet blasting or liquid honing.

Here, in wet blasting, it may be important to collide the slurry uniformly and with high power against the workpiece. For example, when performing peening, which changes the mechanical properties of the workpiece by colliding shots (such as abrasive grains) contained in the slurry against the surface of the workpiece, it is required that the shots have high collision energy and can collide uniformly with the surface of the workpiece.

Nozzle bodies that can spray wet blasting uniformly and with high power over a wide area are known, such as those described in Patent Documents 1 and 2.

The nozzle body described in Patent Document 1 has an air injection passage provided near a slurry storage chamber where a slurry of abrasive grains and liquid is introduced and temporarily stored, and when pressurized air passes through this air injection passage, the slurry is discharged from the slurry storage chamber via an outlet passage having a predetermined length, and the slurry and the pressurized air are sent to a mixing chamber where they are mixed, and the nozzle body sprays the abrasive material in which the pressurized air and slurry are mixed from a slit-shaped injection section, and the outlet passage is provided in a porous structure with small holes arranged in parallel in the longitudinal direction of the outlet passage.

In addition, the nozzle body described in Patent Document 2 is provided with a slurry storage chamber into which a slurry of a mixture of granules and liquid is introduced and temporarily stored, and also with an air storage chamber into which pressurized air is introduced and temporarily stored, and an air injection passage is connected to the air storage chamber, and the pressurized air stored in the air storage chamber is introduced from the air injection passage into a mixing chamber, whereby the slurry is led from the slurry storage chamber to the mixing chamber and the slurry and the pressurized air are mixed, and the nozzle body injects the abrasive material in which the pressurized air and the slurry are mixed from a slit-shaped injection port onto a workpiece, and the slit-shaped injection port has an opening shape that is short in the length direction of the workpiece and long in the width direction, and between the mixing chamber and the slit-shaped injection port, A passageway is provided through which the aerosol can travel in a straight line, and the positional relationship between the air injection passageway, the passageway, and the slit-shaped injection port is set to be linear. The air injection passageway is provided in a porous structure with small holes arranged side by side, and the passageway cross-sectional area of the air injection passageway in a direction perpendicular to the pressurized air passageway is the sum of the passageway cross-sectional areas of the small holes in a direction perpendicular to the pressurized air passageway. The ratio of the opening area of the slit-shaped injection port to the passageway cross-sectional area of the air injection passageway in a direction perpendicular to the pressurized air passageway is set to 2.0 to 1.0:1.0, and further, the ratio of the passageway cross-sectional area of the air injection passageway to the passageway cross-sectional area of the pressurized air in the air storage chamber in a direction perpendicular to the pressurized air passageway is set to 1.0:3.0 or more.

The nozzle body described in Patent Document 1 has a porous structure in which small holes are arranged in the longitudinal direction of the outlet passage, so that a uniform mixture of abrasive grains, liquid, and pressurized air can be sprayed even from a very long slit-shaped nozzle.

The nozzle body described in Patent Document 2 can spray wet blast with high power and uniformity even when the pressure of the pressurized air is increased during the peening process by appropriately setting the ratio between the opening area of the slit-shaped injection port, the passage cross-sectional area of the air injection passage, and the passage cross-sectional area in the direction perpendicular to the direction in which the pressurized air passes through the air storage chamber.

Patent No. 3540713 Patent No. 4210076

In addition, as demands for higher strength and lighter weight for workpieces increase, these demands have been met by replacing existing materials with higher strength ones or by applying heat treatment, but to achieve even higher strength, attention has been focused on the peening method, which can increase strength even with the same material and weight by applying mechanical stress to the material surface.

However, when using wet blasting as a peening method, it is effective to use a high specific gravity (e.g., 6 or more) as a shot material and shoot it at a high concentration (e.g., 30 Vol% (72 wt%) or more) in order to effectively and efficiently apply stress to the surface of the workpiece. However, when a conventional nozzle body is used and a high specific gravity shot material is used, the shot material is biased in the width direction of the nozzle opening due to the influence of inertia, compromising the uniformity of the treatment, and when a high concentration shot material is used, the slurry is likely to clog various passages inside the nozzle body, creating problems in practical application of a peening method using a high specific gravity, high concentration slurry.

The present invention has been made to solve the above problems, and aims to provide a nozzle body that does not impair the uniformity of the treatment and does not cause problems such as slurry clogging, even when a high specific gravity and/or high concentration projection material is used.

The nozzle body according to the present invention for solving the above problems comprises a slurry storage chamber into which a slurry prepared by mixing abrasive grains and a liquid is introduced and temporarily stored, an air storage chamber into which pressurized air is introduced and temporarily stored, and a passageway which communicates with the slurry storage chamber and the air storage chamber and which sprays a band-shaped abrasive material prepared by mixing the slurry and the pressurized air from a slit-shaped spray nozzle extending along the width direction of the workpiece, which is a direction perpendicular to the movement direction when processing with the abrasive material is performed, The air storage chamber is connected to the end of the passing path opposite the injection port, the slurry storage chamber is connected to the passing path via a slurry merging path that opens to the side of the passing path, the slurry merging path has a slurry storage chamber opening extending tangentially from the lower end of the slurry storage chamber, and a merging path that is connected to the slurry storage chamber opening and intersects with the passing path at an acute merging angle, and the merging path is formed in the shape of a slit extending along the width direction.

In the nozzle body according to the present invention, it is preferable that the joining angle of the joining path is in the range of 30° to 60°.

In the nozzle body according to the present invention, it is preferable that the slurry storage chamber has spacer members attached to both ends in the width direction for narrowing the width of the slurry storage chamber .

According to the nozzle body of the present invention, the slurry confluence path has a slurry storage chamber opening that extends tangentially from the lower end of the slurry storage chamber, and a confluence path that communicates with the slurry storage chamber opening and intersects with the passage path at a predetermined angle, and the confluence path is formed in the shape of a slit that extends along the width direction of the workpiece. Therefore, even when a high specific gravity or high concentration projection material is used, the uniformity of the slurry in the width direction of the nozzle body's injection port can be improved, and blockage of the slurry in the passage path and the slurry confluence path can be prevented.

FIG. 1 is a perspective view of a wet blasting treatment apparatus using a nozzle body according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of a nozzle body according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a nozzle body according to an embodiment of the present invention. AA cross-sectional view in FIG. 6 is a graph showing test results of a nozzle body according to an embodiment of the present invention.

Below, preferred embodiments for carrying out the present invention will be described with reference to the drawings. Note that the following embodiments do not limit the inventions according to the claims, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

Figure 1 is a perspective view of a wet blasting processing apparatus using a nozzle body according to an embodiment of the present invention, Figure 2 is an exploded perspective view of a nozzle body according to an embodiment of the present invention, Figure 3 is a cross-sectional view of a nozzle body according to an embodiment of the present invention, Figure 4 is a cross-sectional view taken along line A-A in Figure 3, and Figure 5 is a graph showing test results for a nozzle body according to an embodiment of the present invention.

As shown in FIG. 1, the nozzle body 10 according to this embodiment is suitable for use in a wet blasting treatment device 1. The wet blasting treatment device 1 sprays abrasives 5 onto the surface of the workpiece W held by the holding part 2 to perform surface treatment on the workpiece W. The nozzle body 10 sprays the abrasives 5 in a band shape from a slit-shaped spray nozzle 11 that extends in the width direction of the workpiece W.

The abrasive material 5 is preferably a slurry, which is a mixture of liquid and abrasive grains. The liquid contained in the slurry serves to transport the abrasive grains, which will be described later, to the surface of the workpiece. Therefore, any liquid can be used as long as it can fulfill this role, except for flammable substances. Specifically, it is preferable to use water, from the perspectives of environmental considerations and cost.

The abrasive grains are carried to the workpiece surface by the liquid and serve to perform the desired processing on the workpiece surface. Therefore, any abrasive grains can be used as long as they can perform this function.

Specifically, the material of the abrasive grains may include ceramics, resin, and metal, and more specifically, may include alumina, glass, zirconia, and stainless steel. The shape of the abrasive grains may include polygonal, spherical, and true spherical shapes. The size of the abrasive grains may be appropriately selected from about 1 μm to about 300 μm. In the nozzle body 10 according to this embodiment, it is preferable to use abrasive grains with a high specific gravity (for example, 6 or more), and the diameter of the abrasive grains is preferably about 250 μm.

There is no particular limit to the percentage of abrasive grains contained in the entire slurry, and it can be designed appropriately depending on the material and processing area of the workpiece, as well as the desired degree of processing. For example, a high concentration of 30 vol% (72 wt%) or more relative to the total volume of the slurry is preferable. In this case, stress can be applied to the workpiece W more effectively and efficiently.

In addition to the liquid and abrasive grains, the slurry can contain mixtures with various functions, for example, rust inhibitors. By including a rust inhibitor in the slurry used in the wet blasting method, it is possible to impart rust prevention effects to the surface of the workpiece while simultaneously subjecting it to conventional wet blasting. In place of the rust inhibitor, various additives may be added to the extent that they do not impair the action and effect of each component.

As shown in FIG. 2, the nozzle body 10 is composed of a long member 20 that is long in the width direction of the workpiece W (left-right direction, the direction perpendicular to the direction of movement when processing is performed) and short in the front-rear direction (the direction of movement when processing is performed), a thin, long plate-like member 30 that is long in the width direction and has a slit-shaped injection port 11 at its lower end, which is connected in a vertical manner to the bottom of the long member 20, and a block-shaped fitted member 40 that is connected to the top of the long member 20 in a fitted state.

As shown in FIG. 3, the long member 20 has a plurality of hole-like through passages 21 formed at a predetermined interval inside. The through passages 21 are preferably formed to have a diameter of, for example, about φ2.5, and an air injection passage 43 is formed in the front body 41 (described later) at the upper part of the through passages 21 and is adjacent thereto for introducing pressurized air into the through passages 21.

In addition, a junction path 22 is formed on the side of the long member 20 (the side facing the rear body 42 described later) at an angle to the upper end of the passage path 31 relative to the vertical direction. The inclination angle of the junction path 22 is preferably formed at 30° to 60°, and more preferably at about 45°. Unlike the through path 21, the junction path 22 is preferably formed as a slit that is long in the width direction. Furthermore, a pair of engagement portions 23 are formed below the long member 20, extending downward from the side.

The plate-shaped member 30 is provided with a passage 31 that is connected to the slit-shaped injection port 11 formed at the lower end and through which the injection material 5 can move in a straight line. In addition, a protrusion 32 is formed at the upper end of the plate-shaped member 30 to engage with a pair of engagement portions 23, 23 formed on the long member 20. Furthermore, a pair of engagement protrusions 33 are formed on the sides of the plate-shaped member 30.

The positional relationship between the opening of the air injection passage 43, the through path 21, the passage path 31, and the slit-shaped injection port 11 is set to be linear.

The fitted member 40 is formed of a front body 41 and a rear body 42, and holds the long member 20 and the plate-like member 30 in a direction perpendicular to the width direction. In addition, the front body 41 and the rear body 42 of the fitted member 40 each have a protrusion 44, 44 formed thereon, which engages with the engaging protrusion 33 formed on the plate-like member 30.

The front body 41 is formed with an air storage chamber 45 into which pressurized air is introduced and temporarily stored, an air inlet 46 that introduces pressurized air into the air storage chamber 45, and an air injection passage 43 that communicates with the air storage chamber 45.

As shown in FIG. 2, the air storage chamber 45 is formed by extending in the width direction of the front body 41, and a single air inlet 46 is formed or multiple air inlets 46 (two in the nozzle body 10 according to this embodiment) are formed at a predetermined interval along the width direction. As shown in FIG. 4, the cover body 12 is attached to both ends of the fitted member 40 in the width direction via the seal member 13, and the air storage chamber 45 is closed in the width direction by the cover body 12.

The air injection passage 43 is formed as a through passage whose base end penetrates from the side wall of the air storage chamber 45 on the rear body 42 side toward the rear body 42, and more preferably, the air injection passage 43 extends tangentially from the upper end of the air storage chamber 45. The tip side of the air injection passage 43 communicates with the through passage 21 of the elongated member 20 when combined with the rear body 42.

The rear body 42 is formed with a slurry storage chamber 47 into which the slurry is introduced and temporarily stored, a slurry inlet 48 for introducing the slurry into the slurry storage chamber 47, and a slurry storage chamber opening 49 that communicates with the slurry storage chamber 47.

As shown in FIG. 2, the slurry storage chamber 47 is formed by extending in the width direction of the rear body 42, and a single or multiple slurry inlets 48 (two in the nozzle body 10 according to this embodiment) are formed at predetermined intervals along the width direction. As shown in FIG. 4, the lid body 12 is attached to both ends of the fitted member 40 in the width direction via the seal member 13, and the lid body 12 closes the slurry storage chamber 47 in the width direction.

The slurry storage chamber opening 49 is formed as a through passage that penetrates from the side wall of the slurry storage chamber 47 on the front body 41 side toward the front body 41 at its base end. The slurry storage chamber opening 49 is formed to extend tangentially from the lower end of the slurry storage chamber 47, and its tip end is connected to the merging path 22 of the long member 20. In the nozzle body 10 according to this embodiment, the slurry storage chamber opening 49 and the merging path 22 form a slurry merging path 50.

In addition, among the above components, a protective layer made of urethane rubber or the like is formed on the path through which the slurry passes (the inner wall of the slurry storage chamber 47, the inner wall of the slurry storage chamber opening 49, etc.). This protective layer prevents the path through which the slurry passes from being abraded by the slurry (particularly the granular material), and it has been confirmed that the existence of this protective layer extends the life of the nozzle body 10 by several times.

As shown in FIG. 4, the slurry storage chamber opening 49 is formed as a long slit in the width direction, and spacer members 51 are attached to both ends of the slurry storage chamber 47 in the width direction to prevent the slurry introduced from the slurry inlet 48 from stagnating in the slurry storage chamber 47.

In the nozzle body 10 configured in this manner, the slurry introduced into the slurry storage chamber 47 is introduced obliquely from the side into the passage 31 via the slurry junction passage 50, and is mixed with the pressurized air introduced from the upper end of the passage 31, and is then sprayed from the slit-shaped injection port 11 as the spray material 5. At this time, the slurry is sucked from the slurry junction passage 50 into the passage 31 by the negative pressure of the pressurized air.

In addition, the nozzle body 10 according to this embodiment has a slurry confluence path 50 consisting of a slurry storage chamber opening 49 that extends tangentially from the lower end of the slurry storage chamber 47 and a confluence path 22 that joins at an angle to the passage path 31, so that the slurry does not remain in the path from introduction to injection and become clogged.

Furthermore, because the slurry storage chamber opening 49 is formed in a slit shape, the flow resistance of the slurry inside the nozzle body 10 is reduced, preventing clogging. Even when a high-density shot material is used for the slurry, uniformity is improved in the case of low concentration, and clogging is suppressed in the case of high concentration. Therefore, efficient and effective peening processing can be performed regardless of the concentration of the slurry.

[Example]
Next, the present invention will be described in more detail with reference to examples. First, the nozzle body 10 according to this embodiment was used to spray a slurry using a high specific gravity projection material to check for clogging. As a comparative example, a conventional nozzle body was used under the same conditions to check for clogging. The test conditions are as follows.
Specific gravity: 6.05, median particle size: 250 μm (212-300 μm), air pressure: 0.4 MPa, slurry pressure: 0.24 MPa

The presence or absence of blockage of the nozzle body was confirmed by checking whether the pressure rise in the passageway inside the nozzle body exceeded a predetermined threshold. As a result, it was confirmed that while with a conventional nozzle body blockage occurs in the nozzle body when high-density projection material is used, with the nozzle body 10 according to this embodiment, blockage of the nozzle body 10 does not occur even when high-density projection material is used.

In addition, the results of the above-mentioned clogging check showed that no clogging of the slurry was confirmed in the nozzle body 10 according to this embodiment, even at high concentrations (40 vol% (80 wt%)) when using a high specific gravity projection material.

Next, we checked the uniformity of the concentration of the abrasive material in the width direction sprayed from the nozzle depending on the inclination angle of the merging path of the long member.

The uniformity of the concentration of the spray material was measured by measuring the concentration of the slurry sprayed at a predetermined interval along the width direction of the slit-shaped spray nozzle 11 of the nozzle body 10, and the value obtained by dividing the difference between the maximum and minimum slurry concentrations in the width direction by the average value x 100 (%) was used as a value indicating the uniformity.

As a result, as shown in FIG. 5, it was confirmed that the nozzle body 10 according to this embodiment has significantly improved uniformity compared to the conventional nozzle body when the concentration is low, such as 20 vol% (60 wt%) (Example 1). For example, it was confirmed that the uniformity is better, falling below 40% when the confluence angle is between 35° and 55°. In contrast, when the concentration is 40 vol% (80 wt%) (Example 2), it was confirmed that the uniformity is very good even when the confluence angle is in the range of 30° to 60°. In contrast, it was confirmed that the conventional nozzle body has worse uniformity than the nozzle body 10 according to this embodiment in both cases of a low concentration, such as 20 vol% (60 wt%) (Comparative Example 1), and a high concentration, such as 30 vol% (72 wt%) (Comparative Example 2).

The nozzle body 10 of this embodiment configured in this manner has good uniformity in the nozzle width direction at low concentrations, even when a high-density projection material is used in the slurry, and does not cause blockages inside the nozzle body 10 at high concentrations.

In addition, the nozzle body 10 according to this embodiment has been described as having an air storage chamber 45 formed in the front body 41 of the fitted member 40 and a slurry storage chamber 47 formed in the rear body 42, but it is also possible to provide a slurry storage chamber 47 in the front body 41 and an air storage chamber 45 in the rear body 42. In addition, in the above embodiment, a high specific gravity projection material is used, but a low specific gravity projection material similar to conventional projection materials may also be used. It is clear from the claims that such modified or improved forms are also included in the technical scope of the present invention.

1 wet blasting device, 2 holding part, 5 abrasive, 10 nozzle body, 11 slit-shaped injection port, 12 lid, 20 long member, 21 through path, 22 merging path, 23 engaging part, 30 plate-shaped member, 31 passage path, 32 convex part, 33 engaging convex part, 40 fitted member, 41 front body, 42 rear body, 43 air injection passage, 44 protrusion, 45 air storage chamber, 46 air inlet, 47 slurry storage chamber, 48 slurry inlet, 49 slurry storage chamber opening, 50 slurry merging path, 51 spacer member, W workpiece.

Claims (3)

a nozzle body having a slurry storage chamber into which a slurry of abrasive grains and liquid is introduced and temporarily stored, an air storage chamber into which pressurized air is introduced and temporarily stored, and a passageway communicating with the slurry storage chamber and the air storage chamber and for spraying a band-shaped abrasive material in which the slurry and the pressurized air are mixed from a slit-shaped injection port extending along the width direction of a workpiece, which is a direction perpendicular to the movement direction when processing with the abrasive material is performed ;
The air storage chamber communicates with an end of the passageway opposite to the injection port,
the slurry storage chamber communicates with the passageway via a slurry merging passage that opens to a side of the passageway,
the slurry confluence path includes a slurry storage chamber opening extending tangentially from a lower end of the slurry storage chamber, and a confluence path communicating with the slurry storage chamber opening and intersecting the passage path at an acute confluence angle;
The nozzle body, wherein the joining path is formed in a slit shape extending along the width direction. The nozzle body according to claim 1,
A nozzle body, wherein the joining angle of the joining paths is between 30° and 60°. The nozzle body according to claim 1,
The nozzle body is characterized in that the slurry storage chamber has spacer members attached to both ends in the width direction to narrow the width of the slurry storage chamber .

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