JPH074985U - Flange fitting - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a flange joint that secures a smooth flow while reducing the number of parts and making it lightweight at the connection part of different diameter pipes. [Structure] The first flange on the side of the small-diameter pipe 11 has a first cylindrical portion 6 protruding from the main body wall portion 2, a taper portion 7 that is folded back from the tip thereof and is gradually reduced in diameter, and is connected to the end of the taper portion. It has two cylindrical parts 8. The first cylindrical portion 6 is inserted into the large-diameter pipe 10, a gasket 16 is inserted between the first flange 1 and the second flange 12 on the large-diameter pipe side, and joined by a bolt 17. . Since the flow is rectified by the taper portion 7, a separate rectifying member is not required, the number of parts is reduced, and it is not necessary to perform expansion processing on both pipes, so that the number of steps and cost are reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pipe such as an exhaust pipe of a vehicle, and more particularly to a flange joint used for a connecting portion of pipes having different diameters.

[0002]

[Prior art]

 The present applicant has previously proposed a pipe connecting portion structure for connecting pipes of different diameters having mutually different diameters, which is disclosed in Japanese Utility Model Laid-Open No. 1-102587. As shown in FIG. 4, when connecting the large-diameter pipe 31 and the small-diameter pipe 33, flanges 35 and 37 are provided at the ends of each pipe, and a rectifying member 41 is arranged between them. It was done.

The rectifying member 41 includes a tubular portion 43 that is inserted into the large-diameter pipe 31 from the tip, and a flange portion 45 that is formed at the rear end of the tubular portion and that is interposed between the flanges. The flange portion 45 is sandwiched between the flanges 35 and 37, and is joined by a bolt 51. Then, the inner surface of the tubular portion 43 is formed into a curved surface whose diameter is gradually reduced from the front end side toward the rear end side, and the inner diameter of the tip is substantially the same as the inner diameter of the large-diameter pipe 31, and the inner diameter of the rear end is small. The inner diameter of the diameter pipe 33 is substantially the same. This eliminates turbulence in the flow due to the step at the connecting portion of the pipes having different diameters, and ensures a smooth flow without resistance.

[0004]

[Problems to be solved by the device]

 However, although the connection structure of the above configuration ensures a smooth flow, it requires the rectifying member 41 which is a separate member in addition to the flanges 35 and 37 provided at the ends of both pipes. However, there are many points that need to be improved, such as the increase in the number of pipes, and the need to sandwich this rectifying member between both pipes when connecting them with bolts.

As a countermeasure against this, for example, as shown in FIG. 5, a small-diameter pipe 33 'is formed with an expanded pipe portion 38 in which the diameter of the pipe end is expanded to the same diameter as the large-diameter pipe 31, and the pipe end portion is formed. It may be possible to provide a flange 39. However, for pipes that are often relatively long, expanding the pipe end deteriorates workability and limits the pipe expansion ratio, so the diameter of both pipes to be connected is limited. If the difference is more than a predetermined amount, there is a problem that another member must be interposed. Therefore, in view of the above problems, it is an object of the present invention to provide a flange joint in which the number of parts is reduced and the weight is reduced, and a smooth flow is ensured at the connecting portion of the different diameter pipes.

[0006]

[Means for Solving the Problems]

 Therefore, the present invention is a flange joint used for a connection portion between a large-diameter pipe and a small-diameter pipe, and the first flange provided in the small-diameter pipe has a main body wall portion and the main body wall portion. A first cylindrical portion projecting from the first cylindrical portion, a tapered portion that is folded back from the tip of the first cylindrical portion and has a diameter that is successively reduced, and a second cylindrical portion that is continuous with the end of the tapered portion. It has an outer diameter that is approximately the same as the inner diameter of the large-diameter pipe, and the second cylindrical portion has an inner diameter that is approximately the same as the outer diameter of the small-diameter pipe, and is attached to the small-diameter pipe in the second cylindrical portion. Therefore, the main body wall portion of the first flange is opposed to the second flange provided on the large-diameter pipe to be connected to each other.

[0007]

[Action]

 Since the first flange itself provided on the small-diameter pipe has a taper portion that gradually decreases in diameter from the inner diameter of the large-diameter pipe to the diameter of the small-diameter pipe, the fluid flowing inside requires a separate rectifying member. Be rectified without. Similarly, since the first flange has a taper portion, it is not necessary to perform pipe expansion processing on both large-diameter pipes and small-diameter pipes.

[0008]

【Example】

 FIG. 1 shows an embodiment of the present invention, and particularly shows a first flange attached to a pipe having a small diameter. In the figure, (a) is a sectional view and (b) is a front view. The first flange 1 has a main body wall portion 2 having an oval shape in a front view, and the main body wall portion 2 is provided with a sub-flange 5 on the peripheral edge thereof, and the burring processing portion 3 is used as a center for assembling holes 4 and 4 vertically. Have The burring portion 3 has a first cylindrical portion 6 protruding from the main body wall portion 2 in a direction opposite to the sub-flange 5, and a taper portion 7 that is folded back from the tip of the first cylindrical portion 6 and has a gradually reduced diameter. A second cylindrical portion 8 is formed at the end of the tapered portion 7.

The taper portion 7 extends beyond the wall surface of the main body wall portion 2, so that the second cylindrical portion 8 is located on the opposite side of the first cylindrical portion 6 with the main body wall portion 2 interposed therebetween. . The outer diameter of the first cylindrical portion 6 is set to be substantially the same as the inner diameter of the pipe 10 having a large diameter, and the second cylindrical portion 8 is set to be substantially the same as the outer diameter of the pipe 11 having a small diameter. . The tapered portion 7 may be linearly reduced in its length direction or may be reduced in a curved cross-section.

FIG. 2 shows how to attach the first flange to the pipe and how to connect the pipe. The first flange 1 covers the second cylindrical portion 8 on the pipe end of the small diameter pipe 11 and is fixed by welding, and the end of the tapered portion 7 is substantially aligned with the end edge of the small diameter pipe 11. At the pipe end of the large-diameter pipe 10, a second flange 12 having an inner diameter substantially the same as the outer diameter dimension thereof and having a cylindrical portion 14 protruding from the main body wall portion 13 is melted by covering the cylindrical portion 14. The main body wall 13 of the second flange 12 is provided with mounting holes 15, 15 corresponding to the mounting holes 4, 4 of the first flange 1.

Then, the first cylindrical portion 6 of the first flange 1 fixed to the small-diameter pipe 11 is inserted into the large-diameter pipe 10 from the pipe end, and the first and second first and second pipes 11 facing each other are provided. A gasket 16 is inserted between the flanges 1 and 12, and both flanges are joined by a bolt 17 that penetrates the mounting holes 4 and 15 of each body wall.

This embodiment is configured as described above, and the first cylindrical portion 6 of the first flange 1 provided in the small-diameter pipe 11 is inserted into the large-diameter pipe 10 and fitted therein, Since the tapered portion 7 of the flange 1 of No. 1 smoothly changes from the diameter of the large-diameter pipe 10 to the diameter of the small-diameter pipe 11, the fluid flowing through this pipe connection has a smooth streamline. It is rectified as you draw, and resistance due to disturbance is prevented. As a result, especially when it is used as a pipe for an exhaust pipe of a vehicle, the exhaust pressure is reduced and the exhaust noise is reduced.

Since the taper portion 7 that realizes a smooth change in diameter is integrally formed on the flange for connecting pipes made of a plate material by burring processing, the number of parts is small, and it is possible to reduce The troublesome work of inserting the rectifying member between the flanges is also unnecessary. In addition, it is not necessary to perform pipe expansion work for both large and small diameter pipes, which is inconvenient for the work, and the man-hours and costs can be reduced.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the above embodiment, the taper portion 7 of the first flange extends beyond the wall surface of the main body wall portion to the opposite side, but instead, as shown in FIG. The diameter may be reduced in a section shorter than the length of the first cylindrical portion 6 ′, and the end thereof may be the first flange 1 ′ located on the same side as the first cylindrical portion with respect to the wall surface of the main body wall portion. Further, in the above-mentioned embodiment, the first cylindrical portion is shown to be inserted into the large-diameter pipe 10, but as shown in FIG. The first cylindrical portion 6'of the small-diameter first flange 1'is fitted in the cylindrical portion 14 'of the large-diameter second flange 14' so as to be separated from the main body wall portion of the second flange 12 '. You can also

[0015]

[Effect of device]

 As described above, in the present invention, in the flange joint used for the connecting portion of the different diameter pipe, the flange provided on the small diameter pipe is folded back from the tip of the first cylindrical portion protruding from the main body wall portion to Since it has a taper part that gradually reduces the diameter from the inner diameter to the diameter of the small diameter pipe, the fluid flowing inside is rectified, the resistance due to turbulence is prevented, and the number of parts is reduced without the need for a separate rectifying member. Reduce costs and reduce weight. Similarly, by forming the taper portion on the flange, it is not necessary to expand the long pipe, and the number of working steps can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a flange in an embodiment of the present invention.

FIG. 2 is a diagram showing a pipe connection procedure in the embodiment.

FIG. 3 is a diagram showing another modification of the embodiment.

FIG. 4 is a diagram showing a conventional example.

FIG. 5 is a diagram showing another conventional example.

[Explanation of symbols] 1, 1'first flange 2 main body wall portion 3 burring portion 4 assembly hole 5 sub-flange 6, 6'first cylindrical portion 7, 7'tapered portion 8 second cylindrical portion 10 large Diameter pipe 11 Small diameter pipe 12, 12 'Second flange 13 Main body wall portion 14, 14' Tube portion 15 Assembly hole 16 Gasket 17 Bolt 31 Large diameter pipe 33, 33 'Small diameter pipe 35, 37 Flange 38 Expansion pipe Part 39 Flange 41 Straightening member 43 Cylindrical part 45 Collar part 51 Bolt

Claims (1)

[Scope of utility model registration request] 1. A flange joint used for connecting a large-diameter pipe and a small-diameter pipe, wherein the first flange (1) provided on the small-diameter pipe (11) has a main body wall portion (2). ), A first cylindrical portion (6) protruding from the main body wall portion, a taper portion (7) that is folded back from the tip of the first cylindrical portion and has a diameter that is successively reduced, and a first cylindrical portion that is continuous with the end of the taper portion. And a second cylindrical portion (8), wherein the first cylindrical portion has an outer diameter substantially the same as the inner diameter of the large-diameter pipe (10), and the second cylindrical portion (8) has the outer diameter. A pipe having a diameter substantially the same as the outer diameter of the small-diameter pipe (11) and attached to the small-diameter pipe (11) in the second cylindrical portion (8); The wall portion (2) is opposed to the second flange (12) provided on the large diameter pipe so as to be connected to each other. Flange joint, characterized in that.