Method for producing electrically heated catalyst

Abstract

To provide a method for producing an electrically heated catalyst capable of suppressing deviation deformation of a mat.SOLUTION: A method for producing an electrically heated catalyst includes: a columnar carrier where a catalyst is carried; a surface electrode provided on the outer periphery of the carrier; a flexible mat wound around the outer periphery of the carrier and provided with an opening formation part forming an opening through which the surface electrode is exposed to the outside; and a cylindrical case housing the carrier where the mat is wound. The opening formation part at the mat is compressed while the mat is wound around the carrier using a compression fixture compressing the mat, and thereafter a part different from the opening formation part in the mat is compressed, and the carrier where the compressed mat is wound is pressed into the case.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for producing an electrically heated catalyst. [Background technology]

[0002] Patent Document 1 discloses a technique for producing an electrically heated catalyst by winding a mat around the outer peripheral surface of a cylindrical support carrying a catalyst and then press-fitting the support with the mat wrapped around it into an outer cylinder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-030150 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology disclosed in Patent Document 1, openings are formed in the mat to expose the surface electrodes provided on the outer peripheral surface of the carrier to the outside, so that the holding force is low and there is a risk that the mat will shift and deform when the carrier wrapped around it is pressed into the outer tube.

[0005] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a method for manufacturing an electrically heated catalyst that can suppress the displacement and deformation of the mat. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the manufacturing method of an electrically heated catalyst of the present invention is a manufacturing method of an electrically heated catalyst comprising a cylindrical carrier on which a catalyst is supported, a surface electrode provided on the outer peripheral surface of the carrier, a flexible mat wrapped around the outer peripheral surface of the carrier and provided with an opening forming portion that forms an opening exposing the surface electrode to the outside, and a cylindrical case that houses the carrier with the mat wrapped around it, characterized in that a compression tool for compressing the mat is used to compress the opening forming portion of the mat while the mat is wrapped around the carrier, and then a portion of the mat other than the opening forming portion is compressed, and the carrier with the mat wrapped around it in a compressed state is pressed into the case.

[0007] This allows the entire mat to be compressed with the opening forming portion, which has weak rigidity, compressed first, and the carrier with the mat wrapped around it can be pressed into the case while suppressing deformation of the mat near the opening forming portion, thereby suppressing shifting and deformation of the mat.

[0008] In the above, the compression jig is configured by being divided into a part that compresses the opening forming portion of the mat and a part that compresses a portion of the mat other than the opening forming portion.

[0009] This allows the weak and strong rigidity portions of the mat to be compressed by separate parts. Effect of the Invention

[0010] The manufacturing method of the electrically heated catalyst according to the present invention has the advantage that the entire mat can be compressed while first compressing the opening forming portion, which has weak rigidity, and the carrier with the mat wrapped around it can be pressed into the case while suppressing deformation of the mat near the opening forming portion, thereby suppressing displacement and deformation of the mat. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a development view of a mat to be wrapped around a carrier. [Diagram 2] FIG. 2 is an exploded view showing a schematic configuration of the compression jig according to the embodiment. [Diagram 3] FIG. 3 is a diagram showing step 1 of the method for compressing the mat using a compression jig. [Figure 4] FIG. 4 is a diagram showing step 2 of the method for compressing the mat using a compression jig. [Diagram 5] FIG. 5 is a diagram showing step 3 of the method for compressing the mat using a compression jig. [Figure 6] FIG. 6 is a diagram showing a process of pressing the carrier wrapped with the mat into a case. [Figure 7] FIG. 7 is a diagram showing a case where the first and second window frame portions of the mat are fixed to the carrier with a fixing tape. [Figure 8] FIG. 8 is a diagram showing a state in which the through hole of the case is blocked by a blocking jig. [Figure 9] FIG. 9 is a diagram showing a case in which a chamfered portion is provided on the case. [Figure 10] FIG. 10 is a diagram showing a case where an aligning mechanism is provided in a compression jig. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The method for producing an electrically heated catalyst according to the present invention will be described below, although the present invention is not limited to this embodiment.

[0013] In the manufacturing method of the electrically heated catalyst according to the embodiment, first, a step of winding a mat 30 (see FIG. 3) around a cylindrical support 20 (see FIG. 3) having a pair of surface electrodes 40 (see FIG. 3) arranged opposite each other on the outer circumferential surface is performed. The support 20 is a porous member that supports a catalyst such as platinum or palladium. In addition, the support 20 itself is made of conductive ceramics, such as SiC (silicon carbide), in order to be heated by electrical current. The support 20 has an approximately cylindrical outer shape and a honeycomb structure inside, and exhaust gas passes through the inside of the support 20 in the axial direction of the support 20. The pair of surface electrodes 40 are in physical contact with the support 20 and are electrically connected to it. In addition, the pair of surface electrodes 40 are electrically connected to a power source by electrically connecting the lead-out portions of each of the surface electrodes 40 to the external electrodes.

[0014] Fig. 1 is a development view of a mat 30 wrapped around a carrier 20. The mat 30 is a flexible, strip-shaped heat insulating member. As shown in Fig. 1, the mat 30 has a first window frame portion 31, a second window frame portion 32, a general portion 33, a convex mating portion 34, and a concave mating portion 35, which are divided in the strip-shaped longitudinal direction.

[0015] The mat 30 is wound around the outer circumferential surface of the carrier 20, and is formed into a cylindrical shape by fitting a convex mating portion 34 provided at one end in the longitudinal direction and a concave mating portion 35 provided at the other end in the longitudinal direction. The first window frame portion 31 is provided adjacent to the convex mating portion 34 in the longitudinal direction. The first window frame portion 31 is a mat opening forming portion in which a first window portion 36 is formed, which is surrounded on all four sides by thin frame portions and opens in a rectangular shape. From the first window portion 36, the lead portion of one of the pair of surface electrodes 40 provided on the carrier 20 can be drawn out to the outside. The second window frame portion 32 is provided adjacent to the concave mating portion 35 in the longitudinal direction. The second window frame portion 32 is a mat opening forming portion in which a second window portion 37 is formed, which is surrounded on all four sides by thin frame portions and opens in a rectangular shape. From the second window portion 37, the lead portion of the other of the pair of surface electrodes 40 provided on the carrier 20 can be drawn out to the outside. The general portion 33 is a portion of the mat 30 that does not have any openings.

[0016] In the manufacturing method of the electrically heated catalyst according to the embodiment, after the step of winding the mat 30 around the carrier 20 is completed, the next step is to compress the mat 30 wound around the carrier 20 with a compression jig 1 (see FIG. 2). FIG. 2 is an exploded view showing a schematic configuration of the compression jig 1 according to the embodiment.

[0017] The compression jig 1 according to the embodiment is configured by dividing an upper base part 11, a lower base part 12, an upper pushing part 13, a first lateral pushing part 14, and a second lateral pushing part 15.

[0018] The upper base part 11 has a box-like shape with an open bottom, and has a first opening 11a that opens in a convex curve on one of the pair of long side surfaces, a second opening 11b that opens in a rectangular shape on the top surface, and a third opening 11c that opens in a convex curve on the other of the pair of long side surfaces. The first opening 11a and the third opening 11c are located in the axial direction of the carrier 20 when the carrier 20 wrapped with the mat 30 is set in the compression jig 1.

[0019] The lower base part 12 has a box-like shape with an open top, and has a first opening 12a that opens in a concave (U-shaped) curve on one of the pair of long side sides, a compression part 12b that is formed in a concave curve on the bottom surface, a second opening 12c that opens in a concave (U-shaped) curve on the other of the pair of long side sides, a third opening 12d that opens in a rectangular shape on one of the pair of short side sides, and a fourth opening 12e that opens in a rectangular shape on the other of the pair of short side sides. The compression part 12b of the lower base part 12 is a part on which the carrier 20 with the mat 30 wrapped around it is placed, and is curved so as to follow the outer circumferential surface of the mat 30 wrapped around the carrier 20. The first opening 12a and the second opening 12c are located in the axial direction of the carrier 20 when the carrier 20 with the mat 30 wrapped around it is set in the compression jig 1. The third opening 12d and the fourth opening 12e are positioned in a lateral direction perpendicular to the axial direction of the carrier 20 when the carrier 20 around which the mat 30 is wound is set in the compression jig 1.

[0020] The upper base part 11 and the lower base part 12 are configured so that they can be fixed by a plurality of bolts with the lower end of the upper base part 11 placed on the upper end of the lower base part 12. When the carrier 20 wrapped with the mat 30 is set in the compression jig 1, the dividing position between the upper base part 11 and the lower base part 12 is located above the axial position of the carrier 20 set in the compression jig 1 in the vertical direction perpendicular to the axial direction of the carrier 20.

[0021] The upper pressing part 13 has a compression part 13a formed by a concave curved surface at an end on the side facing the lower base part 12 in the vertical direction. The compression part 13a of the upper pressing part 13 is curved so as to follow the outer peripheral surface of the mat 30 wrapped around the carrier 20. The upper pressing part 13 is configured to be slidable in the vertical direction relative to the first opening 11a of the upper base part 11. The upper pressing part 13 is inserted in the vertical direction relative to the first opening 11a of the upper base part 11 from the upper side (outside) to the lower side (inside). In addition, when the upper pressing part 13 slides in the vertical direction relative to the first opening 11a of the upper base part 11, the side surface of the upper pressing part 13 comes into contact with the inner side surface of the first opening 11a and is guided.

[0022] The first lateral push part 14 has a compression part 14a formed by a concave curved surface at the end on the side facing the second lateral push part 15 in the lateral direction. The compression part 14a of the first lateral push part 14 is curved so as to follow the outer peripheral surface of the mat 30 wrapped around the carrier 20. The first lateral push part 14 is configured to be slidable in the lateral direction relative to the third opening 12d of the lower base part 12. The first lateral push part 14 is inserted from the outside to the inside in the lateral direction relative to the third opening 12d of the lower base part 12. In addition, when the first lateral push part 14 slides in the lateral direction relative to the third opening 12d of the lower base part 12, the side of the first lateral push part 14 comes into contact with the inner side of the third opening 12d and is guided.

[0023] The second lateral push part 15 has a compression part 15a formed by a concave curved surface at the end on the side facing the first lateral push part 14 in the lateral direction. The compression part 15a of the second lateral push part 15 is curved so as to follow the outer peripheral surface of the mat 30 wrapped around the carrier 20. The second lateral push part 15 is configured to be slidable in the lateral direction relative to the fourth opening 12e of the lower base part 12. The second lateral push part 15 is inserted from the outside to the inside in the lateral direction relative to the fourth opening 12e of the lower base part 12. In addition, when the second lateral push part 15 slides in the lateral direction relative to the fourth opening 12e of the lower base part 12, the side of the second lateral push part 15 comes into contact with the inner side of the fourth opening 12e and is guided.

[0024] Next, a procedure for compressing the mat 30 using the compression jig 1 according to the embodiment will be described.

[0025] FIG. 3 is a diagram showing step 1 of the compression method of the mat 30 using the compression jig 1. First, in step 1, the first window portion 36 of the mat 30 is made to correspond to the compressed portion 12b of the lower base part 12 (so that the first window portion 36 and the compressed portion 12b face each other), and the second window portion 37 of the mat 30 is made to correspond to the compressed portion 13a of the upper pressing part 13 (so that the second window portion 37 and the compressed portion 13a face each other), and the carrier 20 wrapped around the mat 30 is placed on the compressed portion 12b of the lower base part 12. At this time, the general portion 33 of the mat 30 is positioned so as to face the compressed portion 15a of the second lateral pressing part 15. In addition, the mat 30's mating portion (the convex mating portion 34 and the concave mating portion 35) is positioned so as to face the compressed portion 14a of the first lateral pressing part 14. In step 1, the first window portion 36 of the mat 30 may be made to correspond to the compression portion 13a of the upper push part 13 (so that the first window portion 36 and the compression portion 13a face each other), and the second window portion 37 of the mat 30 may be made to correspond to the compression portion 12b of the lower base part 12 (so that the second window portion 37 and the compression portion 12b face each other).

[0026] FIG. 4 is a diagram showing step 2 of the compression method of the mat 30 using the compression jig 1. In step 2, the upper base part 11 is placed on the lower base part 12, and the upper base part 11 and the lower base part 12 are fixed by a bolt. Then, the upper pressing part 13 inserted into the first opening 11a of the upper base part 11 is pressed downward in the vertical direction, and the carrier 20 around which the mat 30 is wrapped is sandwiched between the compression part 13a of the upper pressing part 13 and the compression part 12b of the lower base part 12. As a result, the first window frame part 31 of the mat 30 is compressed by the compression part 12b of the lower base part 12, and the second window frame part 32 of the mat 30 is compressed by the compression part 13a of the upper pressing part 13. At this time, the compression jig 1 and the carrier 20 are aligned.

[0027] 5 is a diagram showing step 3 of the compression method of the mat 30 using the compression jig 1. In step 3, the first lateral push part 14 inserted into the third opening 12d of the lower base part 12 and the second lateral push part 15 inserted into the fourth opening 12e of the lower base part 12 are pushed inward in the lateral direction, and the carrier 20 around which the mat 30 is wrapped is sandwiched between the compression part 14a of the first lateral push part 14 and the compression part 15b of the second lateral push part 15. As a result, the mat 30's mating parts (the convex mating part 34 and the concave mating part 35) are compressed by the compression part 14a of the first lateral push part 14, and the general part 33 of the mat 30 is compressed by the second lateral push part 15.

[0028] In the manufacturing method of the electrically heated catalyst according to the embodiment, after the step of compressing the mat 30 wound around the carrier 20 using the compression jig 1 is completed, the next step is to press the carrier 20 around which the mat 30 is wound into a cylindrical case 50 (see FIG. 6), which is an outer cylinder. FIG. 6 is a diagram showing the step of pressing the carrier 20 around which the mat 30 is wound into the case 50.

[0029] In the step of pressing the carrier 20 with the mat 30 wound around it into the case 50, first, as shown in FIG. 6(a), one end of the case 50 in the axial direction is fitted into the first opening 11a of the upper base part 11 and the first opening 12a of the lower base part 12, and the case 50 is set in the compression jig 1. The case 50 is a cylindrical housing for storing the carrier 20 with the mat 30 wound around it. The case 50 covers substantially the entire circumferential direction of the carrier 20 via the mat 30. The case 50 is preferably made of a metal such as a stainless alloy. Two through holes 51 and 52 are provided on the side surface of the case 50 for leading out the lead portions of each of the pair of surface electrodes 40 provided on the carrier 20 to the outside of the case 50. The through holes 51 and 52 of the case 50 are provided in correspondence with the positions where the first window portion 36 and the second window portion 37 of the mat 30 are formed. Then, after setting the case 50 on the compression jig 1, as shown in FIG. 6(b), the carrier 20 with the mat 30 wrapped around it is pushed out from the compression jig 1 toward the case 50, and the carrier 20 with the mat 30 wrapped around it is pressed into the case 50 until the first window portion 36 and the second window portion 37 of the mat 30 face the through holes 51, 52 of the case 50.

[0030] As described above, in the manufacturing method of the electrically heated catalyst according to the embodiment, when the carrier 20 wrapped around the mat 30 having the first window portion 36 and the second window portion 37 is pressed into the case 50, the weak rigidity portion and the strong rigidity portion of the mat 30 can be compressed by separate parts. That is, in the manufacturing method of the electrically heated catalyst according to the embodiment, first, the first window frame portion 31 and the second window frame portion 32, which are the opening forming portion as the weak rigidity portion of the mat 30, are sandwiched and compressed by the compression portion 13a of the upper pressing part 13 and the compression portion 12b of the lower base part 12. Then, the general portion 33 and the joint portion (the convex joint portion 34 and the concave joint portion 35), which are the opening non-forming portion as the strong rigidity portion of the mat 30, are sandwiched and compressed by the compression portion 14a of the first lateral pressing part 14 and the compression portion 15b of the second lateral pressing part 15. Then, the carrier 20 wrapped around the mat 30 compressed by the compression jig 1 is pressed into the case 50.

[0031] As a result, in the manufacturing method of the electrically heated catalyst according to the embodiment, it is possible to suppress the first window frame portion 31 and the second window frame portion 32 from bending like bellows and breaking when the mat 30 is compressed in a state in which the first window frame portion 31 and the second window frame portion 32, which have weak rigidity, are loosened. That is, in the manufacturing method of the electrically heated catalyst according to the embodiment, the entire mat 30 is compressed in a state in which the first window frame portion 31 and the second window frame portion 32, which have weak rigidity, are sandwiched first by the compression jig 1, and in a state in which deformation of the first window frame portion 31 and the second window frame portion 22 in the mat 30 is suppressed, the carrier 20 around which the mat 30 is wound is pressed into the case 50, and the displacement deformation of the mat 30 is suppressed to manufacture the electrically heated catalyst. Furthermore, in the manufacturing method of the electrically heated catalyst according to the embodiment, the first window frame portion 31 and the second window frame portion 32 of the mat 30 are compressed by the compression portion 13a of the upper press part 13 and the compression portion 12b of the lower base part 12, thereby preventing the first window frame portion 31 and the second window frame portion 32 of the mat 30 from hitting the dividing positions (boundaries) of the respective parts of the compression jig 1 when the mat 30 is pressed into the case 50, thereby preventing the mat 30 from breaking.

[0032] FIG. 7 is a diagram showing a case where the first window frame portion 31 and the second window frame portion 32 of the mat 30 are fixed to the carrier 20 with fixing tapes 111 and 112. As shown in FIG.

[0033] 7, on the downstream side of the pressing direction when the carrier 20 wrapped around the mat 30 is pressed into the case 50, the end face of the carrier 20 and the thin frame portion of the first window frame portion 31 are fixed with a fixing tape 111, and the end face of the carrier 20 and the thin frame portion of the second window frame portion 32 are fixed with a fixing tape 112. This makes it possible to prevent the mat 30 from being displaced due to the thin frame portion of the first window frame portion 31 and the thin frame portion of the second window frame portion 32 getting caught on the inner wall surfaces of the through holes 51, 52 when the carrier 20 wrapped around the mat 30 is pressed into the case 50 and the thin frame portion of the first window frame portion 31 and the thin frame portion of the second window frame portion 32 pass through the through holes 51, 52 of the case 50.

[0034] 8 is a diagram showing a state in which the through holes 51, 52 of the case 50 are blocked by the blocking jigs 121, 122. In FIG. 8, when the catalyst 100 is pressed into the case 50, the through holes 51, 52 of the case 50 are blocked by the blocking jigs 121, 122. In a state in which the through holes 51, 52 are blocked by the blocking jigs 121, 122, the inner peripheral surface of the case 50 and the end faces of the blocking jigs 121, 122 are flush with each other. This makes it possible to prevent the mat 30 from being displaced by being caught on the inner walls of the through holes 51, 52 when the catalyst 100 is pressed into the case 50 and the thin frame portion of the first window frame portion 31 and the thin frame portion of the second window frame portion 32 of the mat 30 pass through the through holes 51, 52 of the case 50.

[0035] 9 is a diagram showing a case 50 provided with a chamfered portion 53. In FIG. 9, the chamfered portion 53 is provided on the inner periphery of one end of the case 50 in the axial direction, which is fitted into the first opening 11a of the upper base part 11 and the first opening 12a of the lower base part 12 when the case 50 is set in the compression jig 1. This makes it possible to prevent the mat 30 from getting caught on the end face of the case 50 when the carrier 20 around which the mat 30 is wrapped is pressed from the compression jig 1 into the case 50, even if the axis AX1 of the carrier 20 set in the compression jig 1 is slightly misaligned with the axis AX2 of the case 50.

[0036] Fig. 10 is a diagram showing a case where an aligning mechanism is provided in the compression jig 1. In Fig. 10, as an aligning mechanism for aligning the axis AX1 of the carrier 20 set in the compression jig 1 with the axis AX2 of the case 50, rotatable roller guides 131, 132 are provided on the inner wall surfaces of the first opening 11a of the upper base part 11 and the first opening 12a of the lower base part 12. When setting the case 50 in the compression jig 1, the outer peripheral surface of the case 50 is brought into contact with the roller guides 131, 132, and one end of the case 50 in the axial direction is fitted into the first opening 11a of the upper base part 11 and the first opening 12a of the lower base part 12, whereby the axis AX1 of the carrier 20 and the axis AX2 of the case 50 are aligned with each other. As a result, when the carrier 20 wrapped around the mat 30 is pressed into the case 50 from the compression jig 1, the outer diameter of the mat 30 compressed by the compression jig 1 can be made larger than when there is a misalignment between the axis AX1 of the carrier 20 and the axis AX2 of the case 50, making it possible to increase the margin for mat crushing due to over-compression and to omit the chamfered portion of the case 50. [Explanation of symbols]

[0037] 1 Compression jig 11 Upper base part 11a 1st opening 11b 2nd opening 11c 3rd opening 12 Lower base part 12a 1st opening 12b Compression section 12c 2nd opening 12d 3rd opening 12e 4th opening 13 Upper push part 13a Compression section 14 First horizontal push part 14a Compression section 15 Second side push part 15a Compression section 30 Matt 31 First window frame 32 Second window frame 33 General section 34 Convex joint 35 Concave mating part 36 First window 37 Second window section 40 surface electrode 50 cases 51,52 Through holes 53 Chamfered part 111,112 Fixing tape 121,122 Closing fixture 131,132 Roller guide

Claims

1. A cylindrical support on which a catalyst is supported; a surface electrode provided on an outer peripheral surface of the carrier; a flexible mat that is wrapped around an outer circumferential surface of the carrier and has an opening forming portion that forms an opening through which the surface electrode is exposed to the outside; a cylindrical case that houses the carrier around which the mat is wound; A method for producing an electrically heated catalyst comprising: A method for manufacturing an electrically heated catalyst, comprising: using a compression tool to compress the mat, compressing the opening forming portion of the mat while the mat is wrapped around the carrier; and then compressing a portion of the mat other than the opening forming portion; and pressing the carrier with the compressed mat wrapped around it into the case.

2. The method for manufacturing an electrically heated catalyst as described in claim 1, characterized in that the compression jig is divided into a part that compresses the opening forming portion of the mat and a part that compresses a portion of the mat other than the opening forming portion.

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