JP5677683B2 - Manufacturing method of mixer - Google Patents

Description

  The present invention relates to a method for manufacturing a mixer. More specifically, the present invention relates to a mixer manufacturing method for diffusing a reducing agent introduced into an exhaust passage of an internal combustion engine into exhaust gas.

  Conventionally, a technique for purifying NOx in exhaust gas by injecting and introducing a reducing agent such as urea water from the upstream side of a NOx purification catalyst provided in an exhaust passage of an internal combustion engine is known. In this technique, a mixer is usually provided for diffusing the reducing agent injected into the exhaust passage into the exhaust gas (see, for example, Patent Document 1).

  FIG. 8 is a diagram showing a configuration of a mixer 80 manufactured by a conventional general manufacturing method. Specifically, (a) is a perspective view of the mixer 80, and (b) is a view showing the welded portions 811 and 812 of the swirl blade 81. In the mixer 80, a plurality of swirl blades 81 gathered in the vicinity of the central axis X <b> 1 are joined together by welding or brazing (hereinafter simply referred to as “welding”) at a welding portion 811. These swirl vanes 81 are also joined to the inner wall 820 of the outer cylinder 82 by welds 812. That is, each swirl 81 is restrained by welding at both ends.

  By the way, since the mixer is exposed to a high temperature in the exhaust passage, each swirl blade thermally expands. In this respect, in the mixer 80 shown in FIG. 8, since the swirl vanes 81 are restrained at both ends, the thermal stress generated by the thermal expansion cannot be sufficiently absorbed and thermal deformation cannot be suppressed. Therefore, from the viewpoint of suppressing thermal deformation, it is necessary to increase the plate thickness of the swirl blade 81. In this case, the pressure loss and heat mass increase with the increase in plate thickness, so the exhaust temperature decreases. The NOx purification rate decreases. Further, the increase in the plate thickness increases the weight of the mixer and adversely affects the fuel consumption, and the pressure loss increases and adversely affects the output and the fuel consumption.

  FIG. 9 is a diagram showing a configuration of the mixer 90 manufactured by press molding. Specifically, (a) is a view of the mixer 90 as viewed from the front side (exhaust air inflow side), and (b) is a side view of the mixer 90. In the mixer 90 shown in FIG. 9, each swirl | wing blade 91 is comprised from the same member as the outer cylinder 92, and is not joined mutually. That is, the end 910 on the side of the central axis X2 of each swirl vane 91 is not restrained and is a free end. Therefore, although the thermal stress generated by thermal expansion can be absorbed, each swirl vane 91 itself may be freely deformed.

In addition, in the mixer 90 shown in FIG. 9, it is inevitable that the gap between the swirl vanes 91 is increased in manufacturing, and the reducing agent slips through without colliding with each swirl blade 91. Then, since the reducing agent is not atomized and the reducing agent cannot be uniformly diffused into the exhaust gas, the NOx purification rate decreases.
Further, the mixer 90 shown in FIG. 9 is formed by cylindrically forming a long plate-like member in which each swirl blade 91 is formed by press molding by roll molding, and by caulking or welding at a joint 920 as shown in (b). Manufactured by joining. Therefore, it is difficult to manufacture in the press process, and the manufacturing cost increases because a roll forming process of a separate method is required.

FIG. 10 is a diagram showing a configuration of the mixer 100 manufactured using slit fitting. Specifically, (a) is a perspective view of the mixer 100, and (b) is a diagram showing two swirl blades 110a and 110b. In the mixer 100 shown in FIG. 10, slits 111a and 111a are provided on one adjacent swirl blade 110a, and protrusions 112b and 112b provided on the other adjacent swirl blade 110b are inserted into the slits 111a and 111a. The plurality of swirl blades 110 are connected by fitting. Therefore, in the mixer 100, the thermal stress generated by the thermal expansion of each swirl vane 110 can be absorbed by the relief structure in which the protrusions 112b and 112b slide and retract with respect to the slits 111a and 111a, and thermal deformation can be suppressed.
However, this mixer 100 has a large number of parts and requires a long time for assembly, resulting in an increase in manufacturing cost.

JP 2011-111927 A

  As described above, conventionally, no manufacturing method has been found that can easily and inexpensively manufacture a mixer that can uniformly diffuse a reducing agent in exhaust gas to obtain a high NOx purification rate and suppress thermal deformation. Is the current situation.

  The present invention has been made in view of the above, and an object of the present invention is to easily and inexpensively manufacture a mixer that can uniformly diffuse a reducing agent in exhaust gas to obtain a high NOx purification rate and suppress thermal deformation. It is in providing the manufacturing method of a mixer.

  In order to achieve the above object, the present invention provides a reducing agent that is provided in an exhaust passage (for example, an exhaust pipe 3 described later) of an internal combustion engine (for example, an engine 1 described later) and introduced into the exhaust passage. A mixer (for example, a mixer 10 described later) including a plurality of swirling blades (for example, a swirling blade 12 described later) to be diffused into a plate-like annular portion (for example, an annular portion 21 described later) and A plurality of plate-like standing portions (for example, standing portions 32 to be described later) that are formed of the same member as the annular portion and are provided radially on the outer periphery of the annular portion and are substantially erected with respect to the annular portion. And forming the plurality of standing portions by subjecting the annular portion of a molding member (for example, a molding member 30 described later) to drawing in a direction opposite to the standing direction of the standing portion. Assembled near the central axis of the annular portion (for example, the central axis X described later), Drawing forming a serial plurality of swirler vanes (e.g., draw forming step described later) provides a method for producing a mixer and having a.

In the present invention, a plate-like annular portion, and a plurality of plate-like standing portions that are formed of the same member as the annular portion and are provided radially on the outer periphery of the annular portion and substantially upright with respect to the annular portion. A mixer is manufactured by drawing a formed member. Specifically, by drawing the annular portion of the molded member in the direction opposite to the standing direction of the standing portion, the plurality of standing portions are gathered near the central axis of the annular portion, The swirl wing is formed.
According to the present invention, a mixer shape can be formed from only one forming member only by drawing. That is, after drawing, a mixer can be manufactured easily and inexpensively by simply joining a plurality of swirl blades as necessary.
In addition, according to the present invention, each swirl blade is unconstrained, or even when swirl blades are joined together, and is restrained only at one end, so it can absorb thermal stress caused by thermal expansion, Deformation can be suppressed. Thereby, since the plate | board thickness of a turning blade can be reduced, a manufacturing cost can be reduced and a fuel consumption can be improved since a mixer weight can be reduced. Furthermore, since the heat mass of each swirl blade can be reduced and the exhaust temperature can be prevented from lowering, the NOx purification rate can be improved.
In addition, according to the present invention, by appropriately designing the shape of the standing portion serving as the swirl blade, the structure in which the injected reducing agent can reliably collide with the swirl blade, that is, a plurality of swirl in the vicinity of the central axis. It is possible to manufacture a mixer in which the blades gather and the gap between the swirling blades is small and does not have a blow-through structure. Thereby, since the injected reducing agent can be reliably atomized, evaporation of the reducing agent is promoted, uniform diffusion of the reducing agent into the exhaust gas can be promoted, and a high NOx purification rate can be obtained.

  In this case, in the draw forming step, the draw forming is performed by burring forming in which the opening edge of the annular portion protrudes in the direction opposite to the standing direction of the standing portion and the opening diameter of the annular portion is increased. It is preferable to apply.

  In the present invention, the drawing is performed by burring. As a result, a flange protruding in the direction opposite to the standing direction of the standing portion is formed at the opening edge of the annular portion, and the opening diameter is increased, so that the drawing can be smoothly advanced. . Therefore, according to the present invention, the above-described effects can be achieved more reliably.

  In this case, it is preferable to further include a joining step for joining the plurality of swirl blades formed in the drawing step after the drawing step.

  In the present invention, a plurality of swirl blades formed in the drawing process are joined together. For example, since the end on the central axis side of each swirl vane is not restricted and is a free end, these free ends are joined. Thereby, it is possible to avoid the possibility that each swirl vane itself is freely deformed.

  In this case, the plurality of swirling blades each have a protrusion that protrudes outward substantially along the center axis in the vicinity of the center axis, and in the joining step, the plurality of protrusions are welded, The plurality of swirl blades are preferably joined to each other by either attaching fitting rings that fit into the plurality of protrusions or twisting and crimping the plurality of protrusions.

  In the present invention, a plurality of swirling blades are joined by providing a projecting portion projecting outward substantially along the center axis in the vicinity of the central axis of the plurality of swirling blades, and joining the projecting portions in the joining step. . Specifically, a plurality of swirling blades are connected to each other by either welding a plurality of protrusions, attaching a fitting ring that fits the plurality of protrusions, or twisting the plurality of protrusions. Join. Thereby, it is possible to reliably avoid the possibility that each swirl vane itself is freely deformed. In particular, in the case of joining by a fitting ring or joining by caulking, since no welding is required for manufacturing the mixer, the manufacturing cost can be further reduced.

  In this case, before the draw forming step, a plate-like annular portion (for example, an annular portion 21 described later) and the annular portion are formed of the same member and have a predetermined width in the circumferential direction. The said extension part of the blank material (for example, below-mentioned blank material 20) provided with the plate-shaped several extension part (for example, below-mentioned extension part 22) extended radially from the outer periphery, the said extension It is preferable to further include a bending step (for example, a bending step described later) for forming the standing portion by bending so that a part of the portion stands on the annular portion.

  In this invention, it has a bending process before a drawing process. In this bending step, a plate-like annular portion, and a plurality of plate-like extending portions that are formed of the same member as the annular portion and extend radially from the outer periphery of the annular portion with a predetermined width in the circumferential direction, The extending part of the blank material provided with is bent so that a part of the extending part is erected with respect to the annular part, thereby forming the erected part. Thereby, after bending the extension part of a blank material, a mixer shape can be shape | molded only by drawing and the effect similar to the above-mentioned effect is show | played.

  In this case, the blank material has an R portion (for example, described later) at the end of a fold line (for example, a first fold line 23a and a second fold line 23b, which will be described later) which is bent in the bending step. It is preferable to have R portions 24a, 24b).

  In the present invention, an R portion having an R shape in plan view is formed at the end portion of the folding line that is folded in the folding process in the blank material. Thereby, when it bends at a bending process, it can avoid that a bent part becomes an acute angle shape, and generation | occurrence | production of the crack by thermal expansion can be suppressed.

  In this case, it is preferable that the plurality of extending portions have a substantially quadrangular shape in plan view, and each extending portion is formed with a cutout so as not to interfere with a corner portion of one of the adjacent extending portions. .

  In the present invention, the plurality of extending portions are formed in a substantially rectangular shape in plan view, and each extending portion is notched so as not to interfere with a corner portion of one of the adjacent extending portions (for example, a notch described later). 26). As a result, a larger number of swirl blades can be secured and atomization and diffusion of the reducing agent can be promoted. As a result, the NOx purification rate can be improved.

  In this case, it is preferable that the notch is formed at a position arranged on the rear side of the mixer in each extending portion.

  In this invention, a notch is formed in the position arrange | positioned in the back side of a mixer among each extension part. Thereby, since the notch is arrange | positioned at the back side of a mixer which the injected reducing agent does not hit directly, atomization and spreading | diffusion of a reducing agent are not prevented.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the mixer which can suppress a thermal deformation can be provided while a reducing agent is diffused uniformly in exhaust_gas | exhaustion and a high NOx purification rate is obtained.

It is a figure which shows the exhaust gas purification apparatus of an internal combustion engine provided with the mixer manufactured by the manufacturing method of the mixer which concerns on one Embodiment of this invention. It is a perspective view of the mixer which concerns on the said embodiment. It is a top view of the blank material which concerns on the said embodiment. It is a figure for demonstrating the bending process which concerns on the said embodiment, (a) is a top view of a blank material, (b) is a figure which shows a 1st bending process, (c) is a figure which shows a 2nd bending process. is there. It is a figure for demonstrating the drawing process which concerns on the said embodiment, (a) is a figure when pressing an annular part from upper direction with the small diameter part of a punch, (b) is an annular shape with the large diameter part of a punch. The figure when pressing the part from above, (c) is the figure in the middle of pressing the annular part from above with the large diameter part of the punch, (d) when the punch is pulled out from below the annular part FIG. It is a figure which shows the junction part by a fitting ring as an example of the junction part of the mixer which concerns on the said embodiment. It is a figure which shows the junction part by twist caulking as an example of the junction part of the mixer which concerns on the said embodiment. It is a figure which shows the structure of the mixer manufactured by the conventional general manufacturing method, (a) is a perspective view of a mixer, (b) is a figure which shows the welding part of a swirl | wing blade. It is a figure which shows the structure of the mixer manufactured by press molding, (a) is the figure which looked at the mixer from the front side (exhaust inflow side), (b) is a side view of a mixer. It is a figure which shows the structure of the mixer manufactured using slit fitting, (a) is a perspective view of a mixer, (b) is a figure which shows two swirl | wing blades.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an exhaust purification device 2 of an internal combustion engine (hereinafter referred to as “engine”) 1 including a mixer 10 manufactured by a mixer manufacturing method according to an embodiment of the present invention. The exhaust purification device 2 is provided in the exhaust system of the engine 1. The engine 1 is a diesel engine that directly injects fuel into the combustion chamber of each cylinder.
The exhaust purification device 2 includes a NOx purification catalyst 4 provided in the exhaust pipe 3 of the engine 1 and urea water as a reducing agent injected and supplied into the exhaust pipe 3 upstream of the NOx purification catalyst 4. An injection device 210, and a mixer 10 provided in the exhaust pipe 3 downstream of the urea water injection device 210 and upstream of the NOx purification catalyst 4, and diffuses urea water injected by the urea water injection device 210 into the exhaust gas. .

The urea water injection device 210 injects and supplies urea water as a source of NH _{3 as} a reducing agent to the upstream side of the NOx purification catalyst 4 in the exhaust pipe 3. The urea water injection device 210 includes a urea water tank 211, a urea water injection nozzle 213 including an injection valve (not shown), and a urea water supply path 215.
Urea water is stored in the urea water tank 211, and urea water is injected into the exhaust pipe 3 from the tip of the urea water injection nozzle 213 via the urea water supply path 215 and a urea water pump (not shown). .

  Two injection holes (not shown) are provided at the tip of the urea water injection nozzle 213. The urea water injection nozzle 213 is provided at a position where the urea water injected from the injection hole collides with a swirl vane 12 of the mixer 10 described later. For this reason, the droplets of urea water injected from these two injection holes collide with the swirl vanes 12 of the mixer 10.

The NOx purification catalyst 4 is a conventionally known so-called SCR (selective reduction type) catalyst, and is prepared by a conventionally known preparation method.
The NOx purification catalyst 4 captures NH ₃ produced by hydrolysis of the urea water supplied by the urea water injection device 210. Further, the NOx purification catalyst 4 has at least a NOx purification function, and reduces and purifies NOx in the exhaust gas using NH ₃ captured or supplied.

Next, the configuration of the mixer 10 manufactured by the mixer manufacturing method according to the present embodiment will be described with reference to FIG.
FIG. 2 is a perspective view of the mixer 10 according to the present embodiment. As shown in FIG. 2, the mixer 10 includes an outer ring portion 11 provided on one end side in the central axis X direction and fitted to the inner periphery of the exhaust pipe 3, and a circumferential direction on the other end side in the central axis X direction. A plurality of swirl vanes 12 provided at predetermined intervals and a joint 13 that joins the swirl vanes 12 are provided. The exhaust gas flows from the side where the plurality of swirl vanes 12 and the joint portion 13 are provided (upper side in FIG. 2) toward the outer ring portion 11 side (lower side in FIG. 2).

The outer ring portion 11 is composed of the same member as the plurality of swirl vanes 12. That is, the outer ring portion 11 and the plurality of swirl vanes 12 are integrated.
Each of the plurality of swirl vanes 12 extends from the central axis X to the outer ring portion 11. The swirl vane 12 extends along the central axis X at the front portion 12a on the front side (upper side in FIG. 2) of the mixer 10 into which the exhaust flows. Moreover, in the rear part 12b of the back side (lower side of FIG. 2) of the mixer 10, it inclines and extends in the circumferential direction toward the back side. Thereby, the inflowing exhaust gas can be swirled.
The joint portion 13 is formed by joining a plurality of later-described protrusions 120 assembled in the vicinity of the central axis X by welding.

Next, a mixer manufacturing method according to the present embodiment will be described with reference to FIGS.
The method for manufacturing a mixer according to this embodiment includes a punching process, a bending process, a drawing process, and a joining process.

In the punching process, the blank material 20 is formed by punching a flat metal member into a predetermined shape with a blank punch.
FIG. 3 is a plan view of the blank material 20 according to the present embodiment. The blank material 20 according to the present embodiment is composed of a plate-shaped annular portion 21 and the same member as the annular portion 21 and extends radially from the outer periphery of the annular portion 21 with a predetermined width in the circumferential direction. A plurality of plate-like extending portions 22.

As shown in FIG. 3, the plurality of extending portions 22 include a substantially rectangular (square) quadrangular portion 221 in plan view, and a connecting portion 222 that connects the quadrangular portion 221 and the annular portion 21. Consists of.
The quadrangular portion 221 is formed with a first fold line 23 a that is bent in a bending step, which will be described later, on a straight line substantially along the tangential direction of the annular portion 21. In addition, a second fold line 23b that is bent in a bending process described later is formed on a straight line that forms a boundary between the rectangular portion 221 and the connecting portion 222.

  R portions 24a and 24b having an R shape in plan view are formed at the ends of the first fold line 23a and the second fold line 23b, respectively. R part 24a is formed in the edge part by the side of the annular part 21 among the both ends of the 1st bending line 23a. Further, the R portion 24b is formed at an end portion on the annular portion 21 side among both end portions of the second fold line 23b.

A cutout 26 is formed in the quadrangular portion 221 constituting each extending portion 22 so as not to interfere with the corner portion 25 of the quadrangular portion 221 constituting one adjacent extending portion 22.
The notch 26 is formed at a position arranged on the rear side of the mixer 10 in the quadrangular portion 221 constituting each extending portion 22.

  In the bending step, the extending portion 22 of the blank member 20 described above is bent so that a part of the extending portion 22 stands on the annular portion 21, whereby a standing portion 32 of the molding member 30 described later is provided. Form. The folding process according to the present embodiment includes a first folding process and a second folding process.

4A and 4B are diagrams for explaining a folding process according to the present embodiment, in which FIG. 4A is a plan view of the blank material 20, FIG. 4B is a diagram illustrating the first folding process, and FIG. 4C is a second folding process. It is a figure which shows a process.
First, as shown in FIG. 4B, in the first folding step, each of the plurality of extending portions 22 is folded along a first folding line 23a. At this time, the bending directions of the extending portions 22 are all the same direction (downward in FIG. 4B).

Next, as shown in FIG. 4C, in the second folding step, the plurality of extending portions 22 are each bent at a second folding line 23b. At this time, the bending directions of the extending portions 22 are all the same direction (upward in FIG. 4B).
Thereby, the some standing part 32 of the shaping | molding member 30 mentioned later is formed.

  In the drawing process, drawing is performed on the molded member 30 obtained in the above bending process. Specifically, a plate-like annular portion 21, and a plate-like shape that is formed of the same member as the annular portion 21 and that is provided radially on the outer periphery of the annular portion 21 and substantially upright with respect to the annular portion 21. The plurality of standing portions 32 are formed by drawing in a direction opposite to the standing direction of the standing portions 32 with respect to the annular portion 21 of the forming member 30 including the plurality of standing portions 32. A plurality of swirl vanes 12 are formed by being gathered around the central axis X of the annular portion 21.

5A and 5B are diagrams for explaining the drawing process according to the present embodiment, in which FIG. 5A is a view when the annular portion 21 is pressed from above by the small diameter portion 51a of the punch 51, and FIG. The figure when pressing the annular part 21 from the upper side with the large diameter part 51b of 51, (c) is the figure in the middle of pressing the annular part 21 from the upper part with the large diameter part 51b of the punch 51, (d). FIG. 6 is a view when the punch 51 is pulled out from below the annular portion 21.
As shown in FIG. 5, in the drawing process according to the present embodiment, a small-diameter small-diameter portion 51a provided on the distal end side (downward in FIG. 5) and a large diameter provided on the proximal end side (upper in FIG. 5). Drawing is performed using a punch 51 having a large diameter portion 51b.

  First, as shown in FIG. 5A, the molding member 30 is placed on a cylindrical base 53 whose opening diameter is larger than the opening diameter of the annular portion 21. Then, the annular portion 21 is pressed from above by the small diameter portion 51 a of the punch 51 having a diameter larger than the opening diameter of the annular portion 21 and smaller than the opening diameter of the base 53. That is, the opening edge of the annular portion 21 is protruded in the direction opposite to the standing direction of the standing portion 32 and the opening diameter of the annular portion 21 is increased by drawing by burring.

  As shown in FIG. 5 (b), when the large-diameter portion 51 b of the punch 51 reaches the annular portion 21, the opening edge of the annular portion 21 is opposite to the standing direction of the standing portion 32. A flange is formed. Further, the opening diameter of the annular portion 21 is increased.

  Further, as shown in FIG. 5C, the drawing with the punch 51 is further advanced by the large diameter portion 51 b of the punch 51. Thereby, the standing part 32 gathers toward the central axis X side gradually.

  Then, as shown in FIG. 5 (d), the punch 51 is pulled out from below the annular portion 21 and the base 53, whereby the drawing is completed, and the upright portions 32 gather near the central axis X and contact each other. Touch.

In the joining process, the plurality of swirl blades 12 formed in the drawing process are joined after the drawing process.
In the present embodiment, the plurality of swirl vanes 12 each have a protrusion 120 that protrudes outward (upward in FIG. 5D) substantially along the center axis X in the vicinity of the center axis X. In the joining process, a plurality of protrusions 120 are welded, a fitting ring that fits the plurality of protrusions 120 is attached, or a plurality of protrusions 120 are twisted and caulked. The swirl vanes 12 are joined together.

Here, FIG. 6 is a view showing a joint 60 by a fitting ring 61 as another example of the joint 13 of the mixer 10 according to the present embodiment.
As shown in FIG. 6, recesses 121 are formed on the outer surfaces of the plurality of protrusions 120 at the same position in the central axis X direction. In this example, the plurality of swirl vanes 12 are joined by fitting the fitting ring 61 into the recess 121.

FIG. 7 is a view showing a joint 70 formed by twisted caulking 122 as another example of the joint of the mixer according to the present embodiment.
As shown in FIG. 7, in this example, the plurality of protrusions 120 are twisted around the central axis X (counterclockwise in FIG. 7) and then caulked to join the plurality of swirl vanes 12.

According to this embodiment, the following effects are produced.
In the present embodiment, a plate-like annular portion 21, and a plate-like shape that is formed of the same member as the annular portion 21, is provided radially on the outer periphery of the annular portion 21, and is substantially erected with respect to the annular portion 21. The mixer 10 is manufactured by drawing the forming member 30 including the plurality of standing portions 32. Specifically, by drawing the annular portion 21 of the molding member 30 in the direction opposite to the standing direction of the standing portion 32, the plurality of standing portions 32 are arranged at the center of the annular portion 21. A plurality of swirl vanes 12 are formed in the vicinity of the axis X.
According to the present embodiment, the mixer shape can be formed from one forming member 30 only by drawing. That is, after the draw forming, the mixer 10 can be manufactured simply and inexpensively by simply joining the swirl vanes 12 as necessary.
In addition, according to the present embodiment, each swirl vane 12 is unconstrained, or even when the swirl vanes 12 are joined together, and is restrained only at one end, so it can absorb thermal stress caused by thermal expansion, Deformation can be suppressed. Thereby, since the plate | board thickness of the turning blade 12 can be reduced, manufacturing cost can be reduced, and since the weight of the mixer 10 can be reduced, a fuel consumption can be improved. Furthermore, since the heat mass of each swirl vane 12 can be reduced and a decrease in exhaust temperature can be suppressed, the NOx purification rate can be improved.
In addition, according to the present embodiment, by appropriately designing the shape of the standing portion 32 that becomes the swirl vane 12, the structure in which the injected reducing agent can reliably collide with the swirl vane 12, that is, the central axis X A mixer 10 can be manufactured in which a plurality of swirl vanes 12 are gathered in the vicinity and the gap between the swirl vanes 12 is small and does not have a blow-through structure. Thereby, since the injected reducing agent can be reliably atomized, evaporation of the reducing agent is promoted, uniform diffusion of the reducing agent into the exhaust gas can be promoted, and a high NOx purification rate can be obtained.

  In the present embodiment, the drawing is performed by burring. As a result, a flange projecting in the direction opposite to the standing direction of the standing portion 32 is formed at the opening edge of the annular portion 21 and the opening diameter is enlarged, so that the drawing is smoothly advanced. be able to. Thereby, the above-mentioned effect is more reliably produced.

  In this embodiment, a plurality of swirl blades 12 formed in the drawing process are joined together. For example, since the end on the central axis X side of each swirl vane 12 is a free end without being constrained, these free ends are joined. Thereby, the possibility that each swirl vane 12 may be freely deformed can be avoided.

  Moreover, in this embodiment, the protrusion part 120 which protrudes outward substantially along the central axis X is provided in the vicinity of the central axis X of the plurality of swirl vanes 12, and a plurality of protrusion parts 120 are joined in the joining step. The swirl vanes 12 are joined together. Specifically, the plurality of protrusions 120 are welded, the fitting ring 61 fitted to the plurality of protrusions 120 is attached, or the plurality of protrusions 120 are twisted and caulked. The swirl vanes 12 are joined together. Thereby, it is possible to reliably avoid the possibility that each swirl vane 12 itself is freely deformed. In particular, if the joint portion 70 is joined by the fitting ring 61 or by caulking, no welding is required for the manufacture of the mixer 10, so that the manufacturing cost can be further reduced.

  Moreover, in this embodiment, it has a bending process before a drawing process. In this bending step, a plate-like annular portion 21 and a plurality of plate-like members that are formed of the same member as the annular portion 21 and extend radially from the outer periphery of the annular portion 21 with a predetermined width in the circumferential direction. The extending portion 22 of the blank member 20 including the extending portion 22 is bent so that a part of the extending portion 22 stands with respect to the annular portion 21, thereby forming the standing portion 32. . Thereby, after bending the extension part 22 of the blank material 20, a mixer shape can be shape | molded only by drawing.

  Moreover, in this embodiment, R part 24a, 24b of planar view R shape is formed in one edge part of the 1st bend line 23a and the 2nd bend line 23b which are bend | folded at a bending process among the blank materials 20. FIG. Thereby, when it bends at a bending process, it can avoid that a bent part becomes an acute angle shape, and generation | occurrence | production of the crack by thermal expansion can be suppressed.

  In the present embodiment, the plurality of extending portions 22 are formed in a substantially quadrangular shape in plan view, and the notches 26 are provided in the extending portions 22 so as not to interfere with the corner portions 25 of one of the adjacent extending portions 22. Form. Thereby, more sheets of the swirl vanes 12 can be secured, and the atomization and diffusion of the reducing agent can be promoted. As a result, the NOx purification rate can be improved.

  Moreover, in this embodiment, the notch 26 is formed in the position arrange | positioned in the rear side of the mixer 10 among each extension part 22. FIG. As a result, the cutout 26 is arranged on the rear side of the mixer 10 so that the injected reducing agent does not directly hit, so that atomization and diffusion of the reducing agent are not hindered.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

1. Engine (internal combustion engine)
3. Exhaust pipe (exhaust passage)
4 ... NOx purification catalyst 10 ... Mixer 12 ... Swivel blade 20 ... Blank material 21 ... Annular part (annular part)
22 ... Extension part 23a ... 1st fold line (fold line)
23b ... 2nd fold line (fold line)
24a ... 1st R part (R part)
24b ... 2nd R part (R part)
25 ... Corner portion 26 ... Notch 30 ... Molding member 32 ... Standing portion 61 ... Fitting ring 120 ... Projection portion X ... Center axis

Claims (8)

A method of manufacturing a mixer comprising a plurality of swirl vanes that are provided in an exhaust passage of an internal combustion engine and diffuse a reducing agent introduced into the exhaust passage into the exhaust,
A plate-like annular portion, and a plurality of plate-like standing portions that are formed of the same member as the annular portion and are provided radially on the outer periphery of the annular portion and are substantially erected with respect to the annular portion. The plurality of standing portions are assembled in the vicinity of the central axis of the annular portion by drawing the annular portion of the molded member in a direction opposite to the standing direction of the standing portion. A method for manufacturing a mixer, comprising a drawing process for forming a swirl vane.   In the drawing step, the drawing is performed by burring forming in which the opening edge of the annular portion protrudes in a direction opposite to the standing direction of the standing portion and the opening diameter of the annular portion is increased. The method of manufacturing a mixer according to claim 1.   The method for manufacturing a mixer according to claim 1, further comprising a joining step for joining the plurality of swirl blades formed in the draw forming step after the draw forming step. The plurality of swirling blades each have a protruding portion that protrudes outward substantially along the central axis in the vicinity of the central axis.
In the joining step, the plurality of the plurality of protrusions are welded, a fitting ring fitted to the plurality of protrusions is attached, or the plurality of protrusions are twisted and caulked. The method for manufacturing a mixer according to claim 3, wherein the swirl blades are joined together.   Before the drawing step, a plurality of plate-shaped annular portions and a plurality of plate-shaped extensions that are formed of the same member as the annular portion and extend radially from the outer periphery of the annular portion with a predetermined width in the circumferential direction. A bending step of forming the standing portion by bending the extending portion of the blank material including the protruding portion so that a part of the extending portion stands up with respect to the annular portion. The method of manufacturing a mixer according to any one of claims 1 to 4, wherein   6. The method of manufacturing a mixer according to claim 5, wherein the blank material has an R portion having a R shape in plan view at an end portion of a fold line that is bent in the bending step.   The plurality of extending portions have a substantially rectangular shape in plan view, and each extending portion is formed with a cutout so as not to interfere with a corner portion of one of the adjacent extending portions. Item 7. The method for manufacturing a mixer according to Item 5 or 6.   The method of manufacturing a mixer according to claim 7, wherein the notch is formed at a position of each extending portion disposed on the rear side of the mixer.

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