阅读说明：本技术 制造连接部分的方法 (Method of manufacturing connection part ) 是由 小岛彻 于 2019-09-13 设计创作，主要内容包括：在冲裁步骤中由金属平板冲裁出环形板之后,在翻边步骤中使环形板的内周缘部分向上变形。因此,形成具有直立管状部分和环形板部分的帽状中间产品。此后,将环形板部分的外周缘部分朝向环形板部分的内周缘侧逐步折叠。因此,形成由第一折叠部分45和第二折叠部分49构成的折叠部分24,从而形成具有第二凸缘部分22的连接部分13。(After the annular plate is punched out of the flat metal plate in the blanking step, the inner peripheral edge portion of the annular plate is deformed upward in the burring step. Thus, a hat-shaped intermediate product having an upright tubular portion and an annular plate portion is formed. Thereafter, the outer peripheral portion of the annular plate portion is folded stepwise toward the inner peripheral side of the annular plate portion. Thus, the folded portion 24 constituted by the first folded portion 45 and the second folded portion 49 is formed, thereby forming the connecting portion 13 having the second flange portion 22.)

1. A method of manufacturing a connecting portion applied to a connecting structure in which a first tubular portion and a second tubular portion having an internal flow passage that communicate with each other are joined, a first flange portion provided on the first tubular portion and a second flange portion provided on the second tubular portion are connected together by a clamp, the connecting portion being at least one of a first connecting portion having the first flange portion and a second connecting portion having the second flange portion,

the method comprises the following steps:

a blanking step of blanking a seamless annular plate from the flat plate;

a burring step of burring the annular plate punched in the blanking step to form an annular plate portion and an upstanding tubular portion rising from an inner peripheral edge of the annular plate portion in the annular plate; and

a flange forming step of forming a flange including at least one annular folded portion by folding the annular plate portion from an outer peripheral side of the annular plate portion toward an inner peripheral side of the annular plate portion.

2. The method of manufacturing a connecting portion according to claim 1,

in the flange forming step, the annular plate portion is folded toward a side from which the upright tubular portion protrudes.

3. The method of manufacturing a connecting portion according to claim 1 or 2,

in the flange forming step, folding is performed to form a plurality of folded portions.

4. The method of manufacturing a connecting portion according to any one of claims 1 to 3,

the upstanding tubular portion has an inner diameter that is greater than an outer diameter of the first tubular portion or an outer diameter of the second tubular portion, and,

when the inner diameter of the upright tubular portion is larger than the outer diameter of the first tubular portion, the first tubular portion and the upright tubular portion are fixed to each other in a state in which the first tubular portion is inserted into the upright tubular portion, and when the inner diameter of the upright tubular portion is larger than the outer diameter of the second tubular portion, the second tubular portion and the upright tubular portion are fixed to each other in a state in which the second tubular portion is inserted into the upright tubular portion.

Technical Field

The present disclosure relates to a method of manufacturing a connection portion having a flange portion.

Background

In a known connection structure for connecting a catalytic converter and a turbocharger that are applied to an internal combustion engine or the like of a vehicle, a turbine housing of the turbocharger is connected to an upstream pipe portion disposed on an upstream side of the catalytic converter by using a clip. In this connection structure, the flange portion formed at the connection end of the turbine housing and the flange portion formed at the connection end of the upstream pipe portion are placed on top of each other, and the flange portions are tightly held together by the clamp so that the flange portions are connected together.

In the above-described connection structure, high-temperature exhaust gas discharged from the turbocharger is introduced into the catalytic converter through the upstream pipe portion. In order to prevent the exhaust gas from leaking from the boundary between the turbine housing and the upstream pipe portion, it is necessary to ensure a high level of sealing performance between the mating surfaces (connecting surfaces) of the flange portions.

Reference list

Patent document

Patent document 1: japanese Utility model application laid-open (kokai) No. H6-63820

Patent document 2: japanese patent application laid-open (kokai) No.2017-74614

Disclosure of Invention

Technical problem

Conventionally, it is common practice to form the upstream pipe portion of the catalytic converter by casting. It has been contemplated by those providing the present disclosure that, for weight reduction, the upstream conduit portion may be formed from a metal conduit by bending an end portion of the metal conduit to form a flange portion. Note that, for example, patent document 1 and patent document 2 disclose techniques of forming a flange portion by bending an end portion of a metal pipe, instead of adopting a structure for fastening by a clamp.

In the case where the flange portion for connection is formed by using a metal pipe, the following problems may occur. First, a welded pipe, which is generally used as a metal pipe, is manufactured in the following manner. The metal sheet is rolled into a tubular shape such that the opposite edges butt against each other. Alternatively, a pair of semi-tubular metal members is combined such that opposite edges of one metal member abut against opposite edges of the other metal member. Subsequently, the butted portions are welded, thereby completing the welded pipe. In the case where an end portion of such a pipe in the longitudinal direction of the pipe is bent to form a flange portion, a step or a projection is formed due to welding on the surface of the flange portion. In this case, the flatness of the connection surface deteriorates, and the sealing performance may deteriorate.

One conceivable measure for preventing deterioration of flatness and deterioration of sealing performance is to use a seamless pipe (pipe without a seam) formed by drawing or the like of steel. However, such pipes are expensive and increase production costs.

The above-described problem is not limited to the connection structure for connecting the turbine housing and the upstream pipe portion, and may similarly occur in the following connection structure: in this connection structure, two members having the internal flow passages are connected together by fastening flange portions of the two members together by a clamp so that the internal flow passages communicate with each other.

The present disclosure has been made in view of the above circumstances, and an object is to provide a method of manufacturing a connection portion, which can ensure a high level of sealing performance while suppressing an increase in production cost.

Solution to the problem

An aspect of the present disclosure provides a method of manufacturing a connecting portion applied to a connecting structure in which a first tubular portion and a second tubular portion having an internal flow passage communicating with each other are joined, a first flange portion provided on the first tubular portion and a second flange portion provided on the second tubular portion are connected together by a clamp, the connecting portion being at least one of a first connecting portion having the first flange portion and a second connecting portion having the second flange portion, the method including a blanking step of blanking a seamless annular plate from a flat plate, a burring step of burring the annular plate blanked in the blanking step to form an annular plate portion and an upright tubular portion standing from an inner periphery of the annular plate portion in the annular plate, and a burring step of forming a flange portion including at least one by folding the annular plate portion from an outer periphery side of the annular plate portion toward an inner periphery side of the annular plate portion A flange forming step of forming a flange of the annular folded portion.

According to this aspect, unlike the case where the flange portion is formed by bending the end portion of the welded pipe, no step portion is formed on the connecting surface. Therefore, it is possible to ensure a high level of sealing performance at the connection boundary between the first flange portion and the second flange portion. In addition, since the connecting portion can be formed by using a common flat plate, it is not necessary to use an expensive base material such as a seamless pipe, so that an increase in production cost can be suppressed.

In the flange forming step, the annular plate portion may be folded toward the side from which the upright tubular portion protrudes.

According to this aspect, the folded portion is formed on the side opposite to the connecting surface. Therefore, the flatness of the connection surface can be easily ensured, and the sealing performance can be improved. In addition, since the folded portion matching the shape of the clip is formed by adjusting the bending angle of the folded portion, the flange portion making satisfactory fastening of the clip possible can be formed by a simple method. That is, according to this aspect, a connection portion that achieves both a high level of sealing performance and satisfactory fastening can be formed by a simple method.

In the flange forming step, folding may be performed to form a plurality of folded portions.

According to this aspect, when the first flange portion and the second flange portion are held together by the clip, the flange portion of the connecting portion is prevented from being easily or excessively deformed due to the urging force from the clip. Therefore, a connection portion where the first flange portion and the second flange portion are well connected can be formed.

The upstanding tubular portion may have an inner diameter larger than the outer diameter of the first tubular portion and/or larger than the outer diameter of the second tubular portion, the first tubular portion and the upstanding tubular portion being fixed to each other in a state in which the first tubular portion is inserted into the upstanding tubular portion when the inner diameter of the upstanding tubular portion is larger than the outer diameter of the first tubular portion, and the second tubular portion and the upstanding tubular portion being fixed to each other in a state in which the second tubular portion is inserted into the upstanding tubular portion when the inner diameter of the upstanding tubular portion is larger than the outer diameter of the second tubular portion.

According to this aspect, the connecting portion is formed separately from the first tubular portion and the second tubular portion. Therefore, the length of the upright tubular portion of the connecting portion can be reduced as compared with the case where the connecting portion and the first tubular portion or the second tubular portion are integrally formed. Therefore, when the upright tubular portion is formed in the burring step, the burring depth can be reduced, so that the possibility of occurrence of damage to the ring plate, such as cracking, can be reduced. Therefore, improvement in yield can be expected. Further, since setting of forming conditions and selection of a plate material become easier, production can be made easier.

Other objects, other features, and attendant advantages of the present disclosure will become apparent from the following description taken in conjunction with the accompanying drawings.

Drawings

Fig. 1 is a sectional view of a connection structure to which a connection portion according to the present disclosure is applied.

Fig. 2 is a perspective sectional view of the connection portion.

Fig. 3 is a plan view of the V-shaped clamp.

Fig. 4A is an explanatory view of a blanking step.

Fig. 4B is an explanatory view of the burring step.

Fig. 4C is an explanatory view of the first flange forming step.

Fig. 4D is an explanatory view of the second flange forming step.

Fig. 4E is an explanatory view of the third flange forming step.

Fig. 4A to 4E are a set of explanatory views for describing a method of manufacturing the connection portion.

Detailed Description

One embodiment of the present disclosure will be described with reference to the accompanying drawings.

As shown in fig. 1, in the connection structure 10, a turbine housing 11 of a turbocharger is connected to an upstream pipe portion 12 through a connection portion 13, the upstream pipe portion 12 being connected to an upstream end portion of a catalytic converter. The connecting portion 13 is fixed to the upstream pipe portion 12 by means of a weld 14 and is integral with the upstream pipe portion 12.

The turbine housing 11 accommodates a turbine wheel that rotates when exhaust gas is supplied from the engine. The turbine housing 11 is formed by casting. The turbine housing 11 has a coupling portion 15 (first tubular portion) for joining the housing 11 to the upstream pipe portion 12 (connecting portion 13).

The coupling portion 15 has an approximately cylindrical tubular shape and has a gas passage 16 formed in the coupling portion 15. After rotating the turbine wheel, the exhaust gas passes through the gas passage 16. The exhaust gas in the gas passage 16 is discharged to the outside of the turbine housing 11 through an outlet 17 provided at the downstream end portion of the gas passage 16, thereby leading the exhaust gas to the upstream pipe portion 12.

On the outlet 17 side of the coupling portion 15, a first flange portion 18 is provided on the outer periphery of the coupling portion 15. The first flange portion 18 is formed on the entire periphery of the coupling portion 15. The first flange portion 18 has a bottom surface 18a and an upper surface 18b, the bottom surface 18a being a flat surface extending outward in the radial direction of the coupling portion 15, and the upper surface 18b being an inclined surface inclined downward toward the outer side.

The upstream piping portion 12 (second tubular portion) has a tubular shape of a cylindrical shape and has an inlet 19 at an upstream end portion of the upstream piping portion 12. Exhaust gas discharged from the turbine housing 11 flows into the upstream pipe portion 12 through the inlet 19. In the present embodiment, the upstream pipe portion 12 is formed by means of press forming for weight reduction.

The connecting portion 13 serves as a joint for connecting the upstream pipe portion 12 to the turbine housing 11. As shown in fig. 2, the connecting portion 13 has a tubular portion 21 of a cylindrical shape, the tubular portion 21 being open at opposite ends thereof. The tubular portion 21 has an inner diameter slightly larger than the outer diameter of the upstream pipe portion 12. When the connecting portion 13 is fixed to the upstream pipe portion 12, a part of the upstream pipe portion 12 is inserted into the inside of the tubular portion 21 from the opening of the downstream end portion side of the tubular portion 21, and the outer peripheral surface of the upstream pipe portion 12 and the tubular portion 21 are welded together in this state.

The tubular portion 21 has a second flange portion 22, and the second flange portion 22 is provided at the upstream end portion 21a of the tubular portion 21 and extends over the entire circumference of the tubular portion 21. The second flange portion 22 has a protruding dimension corresponding to the protruding dimension of the first flange portion 18 of the turbine housing 11. Specifically, the protruding dimension of the second flange portion 22 is set such that the protruding position of the outer peripheral edge of the second flange portion 22 approximately coincides with the protruding position of the outer peripheral edge of the first flange portion 18 when the connecting portion 13 is attached to the turbine housing 11 (see fig. 1).

The second flange portion 22 has an extension portion 23 and a folded portion 24. The extending portion 23 extends outward in the radial direction of the tubular portion 21 from the upstream end portion 21a of the tubular portion 21. The folded portion 24 is formed as a result of being bent inward at the outer peripheral edge 23a of the extended portion 23. The extension portion 23 has a flat surface 23b parallel to the bottom surface 18a of the first flange portion 18. The folded portion 24 has an inclined surface 24a inclined downward toward the inside. The folded portion 24 is formed as a result of two folds and is composed of a first folded portion 45 and a second folded portion 49.

The connecting portion 13 is formed of a metal plate by press forming such that the above-described tubular portion 21 and the folded portion 24 are integrally formed. Note that the method of manufacturing the connection portion 13 will be described in detail later.

With regard to the connection (connection portion 13) between the turbine housing 11 and the upstream pipe portion 12, first, the extension portion 23 (surface 23b) of the second flange portion 22 is brought into contact with the bottom surface 18a of the first flange portion 18, thereby placing the connection portion 13 in position with respect to the turbine housing 11. Thus, the gas passage 16 in the turbine housing 11, the space 25 in the tubular portion 21 of the connecting portion 13, and the gas passage 16 in the upstream piping portion 12 communicate with each other, thereby forming a flow passage 27.

In this state, the V-clip 28 is attached from the outer peripheral side in such a manner as to tightly hold the first flange portion 18 of the turbine housing 11 and the second flange portion 22 of the connecting portion 13 together. As shown in fig. 3, the V-shaped clamp 28 is constituted by a pair of semicircular clamp members 29 and 30 arranged to face each other. Opposite ends of the clamping member 29 are coupled to opposite ends of the clamping member 30 by bolts 31 and nuts 32. Each of the gripping members 29 and 30 has an approximately V-shaped cross section. The inclination angle of the inclined portion 33 and the inclination angle of the inclined portion 34 (fig. 1) approximately coincide with the inclination angle of the upper surface 18b of the first flange portion 18 and the inclination angle of the folded portion 24 of the second flange portion 22, respectively.

When the nut 32 is tightened in a state where the V-clip 28 has been attached, urging force for bringing the first flange part 18 and the second flange part 22 close to each other is applied to the first flange part 18 and the second flange part 22 through the inclined parts 33 and 34 of the V-clip 28, respectively, thereby connecting the two flange parts 18 and 22 together.

The length L (fig. 1) of the first folded portion 45 of the second flange portion 22 is determined such that a part of the first folded portion 45 may be located between the extended portion 23 and the second folded portion 49 in the region between the two inclined portions 33 and 34 of the V-shaped clip 28. That is, in the above-described region, the second folding portion 49 receives the urging force from the V-shaped clamp 28 in a state where the first folding portion 45 is interposed between the second folding portion 49 and the extending portion 23.

Then, the rigidity of the second flange portion 22 is increased at the time of fastening of the clip, so that deformation of the second flange portion 22 can be suppressed. Therefore, a sufficient fastening force is generated. In addition, in the case of releasing the re-fastening after the clamp fastening for replacement, repair, or the like of the turbocharger, the connecting portion 13 can be repeatedly used without replacement.

The turbine housing 11 also has an annular recess 35, the annular recess 35 being formed at the bottom of the coupling portion 15 and circumferentially surrounding the outlet 17. A gasket 36 serving as a seal is fitted into the recess 35. Therefore, the sealing performance at the boundary between the turbine housing 11 and the connecting portion 13 is improved, so that the leakage of the exhaust gas can be appropriately prevented. It is to be noted that the above-mentioned annular recess 35 and gasket 36 may be omitted in the case where a sufficient level of sealing performance can be ensured by the connection of the first flange portion 18 with the second flange portion 22.

Next, a method of manufacturing the connection portion 13 will be described with reference to fig. 4.

First, a flat plate formed of metal and having neither a seam nor a step (a recess and a projection) was prepared. The material of the flat plate may be appropriately determined in consideration of, for example, the environment in which the above-described connection structure 10 is used. It is preferable that the material of the flat plate is a metal material excellent in heat resistance, corrosion resistance and formability, such as stainless steel.

Subsequently, the above flat plate is set on a die for blanking, and as shown in fig. 4A, the annular plate 41 is formed by means of blanking (blanking step). In this step, the flat plate is blanked so that the annular plate 41 has an annular shape. At this time, the inner diameter D of the annular plate 41 is made smaller than the inner diameter of the tubular portion 21 (fig. 2) of the connecting portion 13.

Next, as shown in fig. 4B, an upstanding tubular portion 42 is formed along the inner peripheral side of the annular plate 41 (burring step). In this step, a punch having a diameter larger than the above-mentioned inner diameter D is pushed into the inner peripheral edge portion 41a of the annular plate 41 from the lower side of the annular plate 41 to deform the inner peripheral edge portion 41a of the annular plate 41 upward, thereby forming the upright tubular portion 42. Thus, a cap-shaped intermediate product 44 having an annular plate portion (flange portion) 43 is formed. The upright tubular portion 42 becomes the tubular portion 21 in the finished state of the connecting portion 13, and the height H1 (burring depth) of the upright tubular portion 42 is set in accordance with the length that the tubular portion 21 must have.

Next, as shown in fig. 4C, the intermediate product 44 formed in the above-described burring step is curled, thereby forming a first folded portion 45 (first flange forming step). In this step, the first folded portion 45 is formed by folding the outer peripheral edge portion of the annular plate portion 43 toward the inner peripheral edge side in the side toward which the upright tubular portion 42 projects.

Thereafter, as shown in fig. 4D, the outer peripheral edge portion of the annular plate portion 43 having the first folded portion 45 formed thereon is deformed upward, thereby forming the standing portion 47 (second flange forming step). In this step, a part of the annular plate portion 43, including a part of the first folded portion 45, is bent upward with an intermediate position between the outer peripheral surface 42a (see fig. 4C) of the upright tubular portion 42 and the distal end 45a of the first folded portion 45 serving as a bending point. Therefore, the standing portion 47 is formed to have a height H2 larger than the length L of the first folded portion 45. In addition, a flat portion 48 is formed between the upright tubular portion 42 and the upright portion 47. The flat portion 48 becomes the extension portion 23 in the finished state of the connecting portion 13.

Next, as shown in fig. 4E, the erected section 47 is further bent toward the erected tubular section 42 to form a second folded section 49 (third flange forming step). At this time, the bending angle of the second folded portion 49 is set so that the inclined surface 24a (see fig. 2) is formed. Thus, the second flange portion 22 is formed, and the connecting portion 13 is completed.

The present embodiment described in detail above produces the following excellent effects.

After the annular plate 41 is blanked out of a flat plate, the upright tubular portion 41 is formed on the annular plate 41 by means of burring. Thereafter, a step such as a step of folding the outer peripheral edge portion of the annular plate 41 toward the inner peripheral side is performed, thereby forming the connecting portion 13 having the second flange portion 22.

When the connecting portion 13 is used, no step is formed on the connecting surface of the second flange portion 22, at which the second flange portion 22 is connected to the first flange portion 18 (turbine housing 11), and a high level of sealing performance can be ensured at the connecting boundary between the two flange portions 18 and 22. In addition, since the connection portion 13 can be formed by using a common flat metal plate, an expensive base metal is not used, and thus an increase in production cost can be suppressed.

In each flange forming step, the outer peripheral edge portion of the annular plate 41 is folded toward the side toward which the upright tubular portion 42 projects, thereby forming the folded portion 24.

For example, if the above-mentioned peripheral edge portion is folded toward the side opposite to the side toward which the upright tubular portion 42 projects, the folded portion constitutes a connecting surface to be connected with the first flange portion 18. In such a structure, the flatness of the connection surface and the parallelism of the connection surface with respect to the connection surface (bottom surface 18a) of the first flange portion 18 are deteriorated, which may result in deterioration of the sealing performance. In addition, the V-shaped clamp 28 is in contact with a portion of the annular plate portion 43 on the side opposite to the folded portion when connected with the turbine housing 11. Therefore, the annular plate portion 43 must be machined to incline the portion.

In contrast, in the present embodiment, since the folded portion 24 is formed on the side opposite to the connection surface, the flatness of the connection surface can be easily ensured, and the sealing performance can be improved. In addition, since the inclined surface 24a can be formed by adjusting the bending angle of the folded portion 24, the second flange portion 22 having a shape matching the V-shaped clip 28 can be simply formed. That is, with the present structure, the connecting portion 13 that achieves both a high level of sealing performance and satisfactory fastening can be formed by a simple method.

In each flange forming step, the annular plate portion 43 is folded twice, thereby forming the folded portion 24 such that the first folded portion 45 is interposed between the flat portion 48 and the second folded portion 49.

In this case, when the first flange portion 18 and the second flange portion 22 are tightly held together by the V-clip 28, the second flange portion 22 is prevented from being easily or excessively deformed. Therefore, the first flange portion 18 and the second flange portion 22 can be well connected.

Note that, in the above embodiment, the number of times of folding is two. The number of folds is not limited to two and may be increased to three or more times according to, for example, the thickness of the flat panel.

< other embodiment >

The present disclosure is not limited to the above-described embodiments, and the following embodiments are also possible.

(1) In the above embodiment, the connecting portion 13 is applied to the connection between the turbine housing 11 and the upstream piping portion 12. The present disclosure is not limited thereto and may be applied to any of the following connection structures: in the connecting structure, the first tubular portion and the second tubular portion having the internal flow passage are arranged such that the internal flow passage communicates with each other, and the first flange portion provided on the first tubular portion and the second flange portion provided on the second tubular portion are fastened together by a clamp.

(2) In the above embodiment, a seamless flat plate is used. The plate for forming the ring plate 41 is not limited to a seamless flat plate and may be any plate as long as at least the ring plate 41 formed by the blanking step has no seam.

(3) In the above embodiment, the connecting portion 13 and the upstream pipe portion 12 are formed separately. The two portions may be integrally formed as a single body. This structure can be achieved by increasing the vertical deformation amount in the burring step as compared with the vertical deformation amount in the case shown in fig. 4B, thereby increasing the height H1 of the upright tubular portion 42. Such burring (deep drawing) may increase the load acting on the ring plate 41, thereby increasing the possibility of generating cracks or the like in the ring plate 41. Therefore, the yield may be lowered, or setting of forming conditions and material selection may become difficult. In view of this, it is preferable to form the connecting portion 13 and the upstream pipe portion 12 as separate members.

(4) In the above embodiment, the first flange portion 18 is formed by means of casting. Alternatively, the first flange portion 18 may be formed by shaping a flat metal plate. That is, the following structure may be adopted: in this structure, a pair of connecting portions 13 similar in structure are arranged to face each other, and the flange portions of the connecting portions 13 are held tightly together by the V-shaped clamp 28, whereby the two flange portions are connected.

(5) In the above embodiment, the inner diameter of the tubular portion 21 (the upright tubular portion 42) of the connecting portion 13 is made larger than the outer diameter of the upstream pipe portion 12, a part of the upstream pipe portion 12 is inserted into the tubular portion 21, and the upstream pipe portion 12 and the tubular portion 21 are welded together. Alternatively, the outer diameter of the tubular portion 21 may be made smaller than the inner diameter of the upstream pipe portion 12. In this case, a part of the tubular portion 21 is inserted into the upstream pipe portion 12, and the tubular portion 21 and the upstream pipe portion 12 are welded together.

The present disclosure has been described in connection with the embodiments, but the present disclosure is not limited to these embodiments and structures therein. Further, the present disclosure covers various modified embodiments and modifications within the scope of equivalents of the present disclosure. In addition, various combinations and forms, and even other combinations and forms in which only one element is added or two or more elements are added, fall within the scope and spirit of the present disclosure.

List of reference numerals

10 connection structure

12 upstream pipe section (second tubular section)

13 connecting part

15 coupling part (first tubular part)

18 first flange portion

22 second flange portion

24 folded part

27 flow channel

41 Ring plate

42 upright tubular section

43 annular plate portion