JPH04285394A - Pipe joint and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a pipe joint used in a pipeline of a small diameter to the extent of a so-called 1/4 inch pipeline, easy to conduct the roundness finishing work of a curved part in a passage, and used for extremely clean environmental purposes, and a method for manufacturing the same. CONSTITUTION:A pipe joint 1 obtained by boring a metal material to form a passage having a curvature has a roundness diameter in which the inner diameter D0 of a passage 10 is 4.6mm or less and the inner radius(r) of the curvature is 1.0mm or more. The roundness work is performed after the boring work by use of a grinder having a grinding wheel 20 with a shaft which is a rotating body having an outward protruding circular or elliptic outer from in at least its polishing part.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is suitable for use in ultra-clean environments such as semiconductor manufacturing factories where contamination with dust and impurities is avoided and equipment piping and equipment piping are required to achieve an ultra-high vacuum. The present invention relates to a pipe joint for use in and a method for manufacturing the same.

0002

BACKGROUND OF THE INVENTION Pipes used in semiconductor manufacturing equipment and the like require elbow-type, T-type, and other pipe joints for bending and branching the pipes. These fittings cannot be made by casting due to the presence of blowholes, etc., in order to prevent dirt and impurities from getting in and to achieve ultra-high vacuum, so they are made by bending hot-worked pipes. , and die-forged, self-welding joints are used. This pipe joint is made by die-forging a steel material, then drilling an elbow or T-shaped hole with a ball end mill or reamer to form a flow path, and finishing by polishing and cleaning the inner wall of the flow path. In conventional pipe fittings of this type, it is difficult to finish the curved portions of the flow path (including bent portions and branched portions) to an R diameter, so the holes are used as they are without being finished to an R diameter. It had been. In particular, there is a high demand for pipe fittings used in small-diameter pipes called 1/4-inch pipes (inner diameter of the flow path is about 4.5 mm), but the curved portion of the flow path can be efficiently rounded. Since the manufacturing method had not been established, there are no products on the market with rounded curved portions of the flow path.

[0003] If the bent part of the flow path is used without finishing it to an R diameter and the pipe fitting is used with the hole in the same shape, the bent part will have a sharp L-shaped or T-shaped edge, and the fluid inside the pipe will flow smoothly. It is said that because of this, metal inclusions, particles, outgas, etc. remain, making it impossible to achieve ultra-clean and ultra-high vacuum. Therefore, since the conventional die-forged pipe joints are not subjected to R-diameter processing, it has not been possible to sufficiently achieve ultra-cleanliness or ultra-high vacuum.

[0004] Therefore, in facilities and devices that require ultra-cleanliness and ultra-high vacuum, pipes are bent by bending and used as joints. However, there is a limit to bending with a small curvature because the inner wall of the flow path of a bent pipe is prone to wrinkles, and the inner diameter of the bend is 12.5R (mm) for 1/4-inch pipe. I could only get so much. As a result, when a pipe bent by bending is used as a joint, a large space is required for the piping, resulting in an increase in the size of equipment and equipment.

The present invention was made to solve these problems, and is used for small diameter piping such as so-called 1/4 inch piping, and it is easy to round the curved portion in the flow path. The object of the present invention is to provide a pipe joint for use in an ultra-clean environment, which enables the achievement of ultra-cleanliness and ultra-high vacuum in semiconductor manufacturing equipment, etc., and a method for manufacturing the same.

[0006]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a pipe joint in which a metal material is drilled to form a curved flow path, in which the inner diameter of the flow path is is 4.6 mm or less, and the inner diameter of the bend has an R diameter of 1.0 mm or more.

[0007] In the method for manufacturing a pipe joint in which a curved flow path is formed by drilling a metal material, after the drilling process, at least the outer shape of the polished portion is an outwardly convex circular arc or There is provided a method for manufacturing a pipe joint for use in an ultra-clean environment, characterized in that the curve is rounded using a grinder equipped with a shafted grindstone, which is a rotating body with an elongated arc.

[0008] As for the grindstone to be used, the inner diameter of the flow path of the pipe joint is D0, the hole depth of the flow path from the opening end to the bending part is L, and the radius of the bend to be formed by rounding the bend. When r is the diameter of the grinding wheel at the center of the polished part of the grinding wheel, the following formula: (D0 /L)>1/3, (D0 /2
)>(D/2)≧0.6 r (D0/L)≦1/
3, (D0 /2)>(D/2)≧0.9
It is preferable to satisfy r.

[0009]

[Operation] In the pipe joint of the present invention, the inner diameter of the curve of the flow path is 1.
It has been processed to have a radius of 0 mm or more, allowing fluid to flow smoothly through the flow path, with no impurities or gas seeping out from the inner wall of the flow path, making it suitable for use in ultra-clean environments. In the above-mentioned R-drop machining, the inner diameter of the flow path is D0, the hole depth of the flow path is L, and the bending radius to be formed by the R-drop machining of the bend is r, and in relation to these, the grindstone diameter D is within a predetermined range. By using the internal grindstone, it is possible to accurately process the R diameter of a bend in a pipe joint with a flow path inner diameter of 4.6 mm or less.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an elbow-type (L-type) forged pipe joint 1 according to the present invention. As will be described in detail later, this pipe joint 1 is manufactured by stamping and forging a steel material such as stainless steel or an aluminum material, and then forming an L-shaped block body 2 at both ends 10a and 10b.
is machined into a pipe shape, and the outer diameter D1 is so-called 1/4
Finished to standard inch diameter. This finishing process on the outer diameter of both ends may be omitted depending on the case. In addition, we omit die forging and cut directly from the material,
It may be processed into an L-shape with pipe-like ends. and,
The flow path 10 is also bored from both ends 10a and 10b using a ball end mill, so that it is bent at right angles in an L shape, and its inner diameter D0 is finished to a standard diameter of 1/4 inch size. After this hole-drilling process, the curved inner diameter portion 10d of the flow path is subjected to R-removal processing so that the R diameter of the curved inner diameter portion 10d, that is, the radius r, is 1.0 mm or more, preferably 1.5 mm or more, and more preferably , 1.9mm
It is formed as above. This R diameter is preferably as large as possible from the point of view of forming a smooth fluid flow, but as will be described later, it is limited by the diameter of the grinding wheel of the grinder.
The upper limit is a value slightly smaller than /2 D0 (approximately 2.3 mm). On the other hand, the curved outer diameter portion 10c is machined to have an R diameter of 1/2 D0 by drilling with a ball end mill. Both ends 10a and 10b of this pipe joint 1 are butt-welded to the pipes 4 and 5 to be connected using an automatic welding machine.

[0011] The present inventors have discovered that the curved inner diameter portion 10d of a small pipe fitting of approximately 1/4 inch size, that is, the flow path diameter is 4.6 mm or less, is brought into the above-mentioned required range by R-diameter machining. We have conducted extensive research into the shape and size of the grinder's whetstone necessary to form a radius r of 1.0 mm or more, preferably 1.5 mm or more, and more preferably 1.9 mm or more. As a result, it was first discovered that the shape of the grindstone needs to be a rotating body with a circular or oval cross section, as shown in FIG. However, the shape of the entire grindstone does not need to be a rotating body with a circular or oval cross section, and it is sufficient if the external shape of at least the polishing area is an outwardly convex arc or an elliptical arc.

If a cylindrical-shaped grindstone 30 as shown in FIG. 3 is used for this R-diameter machining, instead of using the above-mentioned grindstone, the R-diameter of the inner diameter portion 10d' will not draw a smooth arc. , the cross-sectional shape has a sharp tip P1. In particular, the ratio of hole depth L to channel diameter D0 is L/
When D0 becomes large, there is a strong tendency to end up with such a shape. On the other hand, when a drum-shaped grindstone 32 as shown in FIGS. 4 and 5 is used, the edge of the grindstone 32 causes scratches on the inner surface of the flow path.
This is not desirable.

[0013]The inventors further discovered that the inner diameter D of the flow path
As a result of various studies on the grinding wheel diameter D of the grinder to be used in relation to the hole depth L of the flow path and the bending inner diameter r to be formed, it was found that a grinding wheel with a grinding wheel diameter D within the following predetermined range was selected. We obtained the knowledge that good results can be obtained if selected. When (D0 /L)>1/3, (D0 /2
)>(D/2)≧0.6 r (D0/L)≦1/
3, (D0 /2)>(D/2)≧0.9
r A pipe joint that is shorter than the flow path diameter, that is, the flow path diameter D0
is the flow path length L of the pipe joint (this length L is the length L at both ends 10a,
((D0 /L)
>1/3), this bending part R processing in the pipe joint can be performed by tilting the rotating shaft (handle) 22 (see Fig. 2) of the grinding wheel, so even if the grinding wheel diameter D is small, it can be processed with a large R. The diameter can be formed. On the other hand, (D0 /L)≦1/
3, the handle 22 of the grindstone is connected to the flow path 10.
Since it is necessary to carry out the R-diameter machining in a state where the grindstone is approximately parallel to the R-diameter, it is better that the grindstone diameter D is as large as possible, and the minimum value is regulated based on the shape of the R-diameter to be formed. Note that the upper limit of the grindstone diameter D is regulated by the flow path diameter D0, and is set to a value slightly smaller than the flow path diameter D0.

Next, a method for manufacturing the pipe joint 1 will be explained with reference to FIGS. 2, 6, 7, and 8. First, a steel material such as stainless steel is forged using a die forging machine (step S1 in FIG. 8). This forging step may be performed by a conventionally known processing method, and the outer periphery of both ends 10a, 10b may be finished and machined if necessary.

Next, both ends 10 are cut using a ball end mill 8.
Drilling is performed from a and 10b to form a flow path 10 (step S2). This hole-drilling process may also be performed by a conventionally known processing method. When this hole drilling process has just been completed,
As shown in FIG. 6, in addition to leaving a sharp cutting line 10f cut by the end mill 8 from both ends 10a and 10b, a sharp edge is also left at the inner corner 10e of the bend. In a conventional pipe joint, these cutting lines 10f and corner portions 10e are left as they are without being cut off. Note that, if the curved outer diameter portion 10c is formed in the shape of the cutting edge of the ball end mill 8 accurately, the R diameter of this outer diameter portion 10c can be easily machined.

Next, a grinder is used to process the inner surface radius (step S3). FIG. 2 shows a curved corner portion 1 of the curved corner portion 1 by inserting the grinding wheel 20 of the grinder from the end surface 10b.
6 shows how the inner diameter portion 10d (indicated by a broken line in FIG. 6) is formed by grinding 0e. This grindstone 20 is made of, for example, diamond abrasive grains of an appropriate size bound together with a binder, and is a rotating body having a circular or oval cross-sectional shape. The whetstone 20 has a handle 22
The base end of the handle 22 is attached to a grinder body (not shown). As a grinder,
Air grinders and electric grinders are used. Whetstone 2
The shape and diameter of the grinding wheel 0 are selected as described above.

When a rotating body with an oval cross-sectional shape is used as a grindstone, the diameter of the grindstone 21 in the direction perpendicular to the central axis of the handle 23 is defined as the major axis diameter D, as shown in FIG. Ba,
The ratio of the major axis diameter D to the minor axis diameter Ds (Ds/D) is 0.8 to 1
．． It is desirable to use a range of 2. Further, the grindstone shape may be a bowl-shaped one. The end surfaces 10a, 10b are polished by the grindstone 20 (21) as described above.
The inner surface R of the pipe joint 1 is cut by inserting the grindstones 20 alternately from both sides of the
Drop processing is performed to make the R diameter of the bent inner diameter portion 10d to 1.0 mm or more, preferably 1.5 mm, as described above.
As mentioned above, it is preferably formed to have a thickness of 1.9 mm or more. This R diameter reduction process is a manual process that requires some skill, but by selecting the grinding wheel diameter D as described above, it is possible to
．． Even if it is a small diameter tube of 6 mm or less, R diameter processing can be easily and accurately performed.

[0018] When the inner surface R is finished, the flow path 10 is finished polished (step S4) and cleaned (step S5) by a conventional method such as buffing, and the manufacture of the pipe joint 1 is completed. Note that various processing methods can be applied to the final polishing step of step S4 and the cleaning step of step S5, and are not limited to a specific processing method.

The present invention is not limited to the elbow type pipe joint of the above-described embodiment. That is, T shown in FIG.
It can also be applied to a type of pipe joint 3. The T-shaped pipe joint 3 shown in FIG. 9 is a joint in which a flow passage 30 is formed in a T-shape, and the flow passage inner diameter D is 4.6 mm or less. Then, the bent inner diameter portions 30a, 30a are both the elbow type pipe fittings 1 described above.
Similarly, the inner surface is rounded by the grindstone 20,
Their R diameters are processed to be 1.0 mm or more.

[0020]

As is clear from the above description, according to the present invention, in a pipe joint in which a curved flow path is formed by drilling a metal material, the inner diameter of the flow path is 4. ．．
6 mm or less, and the inner diameter of the bend has an R diameter of 1.0 mm or more.

[0021] Therefore, when this forged pipe joint is used as a joint for a small diameter pipe such as a so-called 1/4 inch pipe in semiconductor manufacturing equipment, the fluid flow in the joint is smooth and particles and outgas are prevented. Retention can be suppressed to a minimum, making it easier to achieve ultra-cleanliness, ultra-high vacuum, etc. According to another aspect of the invention, a method for manufacturing a forged pipe joint for use in an ultra-clean environment, after drilling, at least the outer shape of the polished portion is an outwardly convex circular arc or a rotation of an elongated circular arc. The method is characterized in that the curve is rounded using a grinder equipped with a grindstone with a shaft. If the hole depth is L, and the radius of the bend to be formed by the R-cutting process is r, then the grindstone diameter D at the center of the grinding part of the grindstone to be used is
is the following formula, when (D0 /L)>1/3, (D0 /2
)>(D/2)≧0.6 r (D0/L)≦1/
3, (D0 /2)>(D/2)≧0.9
A grindstone that satisfies r is preferably used.

[0022] Therefore, it is possible to perform the inner surface radius reduction processing of a joint for a small diameter pipe such as a 1/4 inch pipe with high precision and with ease, and it is now possible to perform the inner surface radius reduction processing, which has not been commercially available in the past. This has the excellent effect of making it possible to manufacture pipe fittings that are

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an elbow-type pipe joint according to the present invention.

FIG. 2 is a cross-sectional view of the pipe joint shown in FIG. 1 in a state where the inner surface R is removed.

FIG. 3 is a partially enlarged cross-sectional view showing a machining situation for explaining the disadvantages when machining is performed using a cylindrical grindstone during inner surface R removal machining.

FIG. 4 is a cross-sectional view showing a machining situation for explaining the inconvenience when machining is performed using a drum-shaped grindstone at the time of machining to remove the radius of the inner surface.

FIG. 5 is a sectional view taken along line V-V in FIG. 4;

FIG. 6 is a cross-sectional view of the pipe joint shown in FIG. 1 after drilling has been completed.

FIG. 7 is a plan view showing the shape of a grindstone that is a rotating body with an oval cross-sectional shape.

FIG. 8 is a flowchart showing the manufacturing procedure of the forged pipe joint of the present invention.

FIG. 9 is a sectional view of a T-shaped pipe joint according to the present invention.

[Explanation of symbols]

1 Elbow type pipe fitting 3 T-type pipe fitting 8 Ball end mill 10 Flow path 10d　　　Bent inner diameter part 20, 21 Whetstone 30 Flow path 30a　　　Bent inner diameter part

Claims (3)

[Claims] 1. A pipe joint in which a curved channel is formed by drilling a hole in a metal material, wherein the channel has an inner diameter of 4.6 mm or less, and the curve has an inner diameter of 1.0 mm.
A pipe fitting for use in ultra-clean environments, characterized by having an R diameter of mm or more. 2. A method for manufacturing a pipe joint in which a curved flow path is formed by drilling a metal material, wherein after the drilling, at least the outer shape of the polished portion is
A method for manufacturing a pipe joint for use in an ultra-clean environment, characterized in that the curve is rounded using a grinder equipped with a grindstone with a shaft, which is a rotating body having an outwardly convex circular arc or an elongated circular arc. 3. The inner diameter of the flow path of the pipe joint is D0, the hole depth from the opening end of the flow path to the bending part is L, and the radius of the bend to be formed by rounding the bend is r.
Then, when the diameter D of the grindstone at the center of the polishing area of the grindstone used is the following formula, (D0 /L)>1/3, (D0 /2
)>(D/2)≧0.6 r (D0/L)≦1/
3, (D0 /2)>(D/2)≧0.9
The method for manufacturing a pipe joint according to claim 2, characterized in that r is satisfied.