Method for manufacturing an electrically heated catalyst device

Abstract

To protect an electrode and an outer cylinder when inserting a base material into the outer cylinder, and to easily draw out a wiring member connected to the electrode after being inserted into the outer cylinder.SOLUTION: A manufacturing method of an electrical heating-type catalyst device includes: a fixing step for pasting a fixing tape to a base material so that a window held on an electrode in a state that a lead is folded a plurality of times and arranged at the fixing tape exposes a part of the lead, and fixing the lead by the fixing tape; a pressure-insertion step for winding a holding mat around the base material in a state that the lead is held by the fixing tape, and pressure-inserting the base material into an outer cylinder together with the holding mat; and a draw-out step for drawing out the lead from the window part while the fixing tape is pasted on the base material after the pressure-insertion step, and drawing out the lead to the outside of the outer cylinder from an opening of the outer cylinder.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an electric heating type catalyst device.

Background Art

[0002] Patent Document 1 discloses a method for manufacturing an electric heating type catalyst device including an outer cylinder that houses a base material, and an electrode that is attached to the outer peripheral surface of the base material and has a bellows-shaped lead-out portion, in which the lead-out portion of the electrode is pulled out to the outside from the opening of the outer cylinder.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When manufacturing an electric heating type catalyst device, the base material is inserted into the outer cylinder with the electrode attached to the outer peripheral surface of the base material. At the time of this insertion, if the electrode attached to the base material is bellows-shaped, the electrode may interfere with itself, or the electrode may interfere with the outer cylinder as it tries to extend from the folded shape. When this interference occurs, there is a risk of damaging the electrode itself or the outer cylinder.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing an electric heating type catalyst device that protects the electrode and the outer cylinder when inserting the base material into the outer cylinder, and that can easily pull out the wiring member connected to the electrode after insertion into the outer cylinder.

Means for Solving the Problems

[0006] The present invention relates to a method for manufacturing an electrically heated catalyst apparatus comprising: a substrate that generates heat when an electric current is passed through it; an electrode attached to the outer surface of the substrate; a thin plate-shaped lead connected to the electrode; an outer cylinder covering the outer surface of the substrate and having an opening for pulling the lead outwards; a holding mat interposed between the substrate and the outer cylinder to hold the substrate; and an electrode terminal disposed on the outside of the outer cylinder and electrically connected to the electrode via the lead, wherein the electrode applies a voltage to the substrate, thereby heating a catalyst supported on the substrate through the substrate, wherein the lead is folded multiple times. The invention is characterized by including a fixing step of attaching the fixing tape to the base material such that the lead is held on the electrode in a fixed state and a window portion provided in the fixing tape exposes a part of the lead, and fixing the lead with the fixing tape; a press-fitting step of wrapping the retaining mat around the base material with the lead held by the fixing tape, and press-fitting the base material together with the retaining mat into the outer cylinder; and a pull-out step of pulling the lead out from the window portion while the fixing tape is still attached to the base material, and pulling the lead out to the outside of the outer cylinder from the opening of the outer cylinder. [Effects of the Invention]

[0007] In this invention, the electrode and the outer cylinder are protected when inserting the substrate into the outer cylinder, and the wiring member connected to the electrode can be easily pulled out after insertion into the outer cylinder. [Brief explanation of the drawing]

[0008] [Figure 1] This figure schematically shows an electrically heated catalyst device in an embodiment. [Figure 2] This is a diagram illustrating the state in which the retaining mat is wrapped around the base material. [Figure 3] This diagram illustrates the state in which the leads are connected to the electrode terminals. [Figure 4] This diagram illustrates the state in which the lead is pulled out from the opening of the outer cylinder. [Figure 5]This diagram illustrates how a folded lead is held in place by the fixing tape. [Figure 6] This is a diagram to explain the shape of the lead. [Figure 7] (a) is a diagram showing the surface of the fixing tape, and (b) is a diagram showing the back surface of the fixing tape. [Figure 8] This diagram shows the jig inserted into the lead extraction hole. [Figure 9] This diagram shows the state where the tip of the lead is pulled out while the first bent portion is held in place by the fixing tape. [Figure 10] This figure shows the state where the tip portion of the lead, including the first bent portion, is pulled out while the second bent portion is held in place by the fixing tape. [Figure 11] (a) is a diagram showing the fixing tape of the first modified example, (b) is a diagram showing the fixing tape of the second modified example, (c) is a diagram showing the fixing tape of the third modified example, (d) is a diagram showing the fixing tape of the fourth modified example, and (e) is a diagram showing the fixing tape of the fifth modified example. [Modes for carrying out the invention]

[0009] The following describes in detail the method for manufacturing an electrically heated catalyst device according to embodiments of the present invention. However, the present invention is not limited to the embodiments described below.

[0010] An electrically heated catalyst device in an embodiment will be described with reference to Figures 1 to 7. The electrically heated catalyst device 1 is mounted on a vehicle equipped with an internal combustion engine and is installed in the exhaust passage of the internal combustion engine. The electrically heated catalyst device 1 comprises a base material 2 that supports the catalyst, a pair of electrodes 3, a holding mat 4, a pair of electrode terminals 5, leads 6, fixing tape 7, and a case 10. The base material 2, the pair of electrodes 3, the holding mat 4, the pair of electrode terminals 5, the leads 6, and the fixing tape 7 are housed inside the case 10.

[0011] Figure 1 shows the lead 6 fixed to the fixing tape 7. Figure 2 shows the base material 2 with the holding mat 4 wrapped around it. Figure 3 shows the base material 2 housed in the outer cylinder 11. Figure 4 shows the lead 6 pulled out from the outer cylinder 11. Also, for the sake of clarity, the fixing tape 7 is omitted in Figures 3 and 4. Figure 5 shows the lead 6 before it is pulled out from the outer cylinder 11. Figure 6 shows the lead 6 before it is fixed with the fixing tape 7. Figures 7(a) and 7(b) show the shape of the fixing tape 7.

[0012] In the electrically heated catalyst device 1, the electrode terminals 5 apply a voltage to the substrate 2 via the leads 6 and electrodes 3, causing the substrate 2 to generate heat and the catalyst supported on the substrate 2 to be heated.

[0013] The substrate 2 is a honeycomb structured carrier with multiple passages formed along the direction of exhaust flow. A catalyst is supported on the surface of each passage of the substrate 2. For example, a three-way catalyst is supported on the substrate 2. The substrate 2 is conductive and generates heat when an electric current is passed through it. The substrate 2 is made of, for example, silicon carbide. The substrate 2 is formed in a cylindrical shape and extends along the direction of exhaust flow. Note that the axial direction and circumferential direction shown in Figure 1, etc., refer to the axial direction and circumferential direction of the substrate 2.

[0014] The pair of electrodes 3 are components for applying voltage to the substrate 2. As shown in Figure 1, the electrodes 3 are attached to the outer circumferential surface of the substrate 2. The electrodes 3 are conductors made of metal. The pair of electrodes 3 extend in the circumferential direction of the substrate 2 as well as in the axial direction of the substrate 2. As shown in Figure 2, the electrodes 3 are positioned corresponding to the opening 4a of the retaining mat 4.

[0015] The holding mat 4 is a mat that holds the base material 2. As shown in FIGS. 2 and 4, the holding mat 4 is wound around the outer peripheral surface 2a of the base material 2 and is interposed between the outer cylinder 11 of the case 10 and the base material 2. The outer cylinder 11 is a case portion that houses the base material 2 and is made of metal. The outer cylinder 11 extends along the axial direction of the base material 2. The holding mat 4 is a component that holds the base material 2 at a predetermined position within the outer cylinder 11 and is made of an electrically insulating material. As shown in FIG. 2, the holding mat 4 has an opening 4a provided at a position corresponding to the pair of electrodes 3. The opening 4a is a rectangular opening and is formed in an opening shape larger than the electrodes 3 and the leads 6. Since the holding mat 4 having electrical insulation holds the base material 2, the pair of electrodes 3 attached to the base material 2 are electrically insulated from the outer cylinder 11.

[0016] The pair of electrode terminals 5 are rod-shaped electrodes that function as external electrodes with respect to the electrodes 3. The electrodes 3 are internal electrodes disposed inside the outer cylinder 11, and the electrode terminals 5 are external electrodes disposed outside the outer cylinder 11. The electrode terminals 5 are housed inside the electrode cover 12 of the case 10. The electrode cover 12 is made of metal. The electrode terminals 5 are electrically connected to an external power source, for example, via a cable provided outside the case 10. Also, the electrode terminals 5 are electrically connected to the electrodes 3 via the leads 6.

[0017] The lead 6 is a thin plate-shaped wiring member connected to the electrode 3. The lead 6 is made of, for example, stainless steel. The lead 6 is formed in a strip shape that extends with a predetermined width from the proximal end side connected to the electrode 3 to the distal end side of the distal end portion 6a. As shown in FIGS. 5 and 6, the lead 6 is bent a plurality of times with a predetermined length and is held in a folded state on the electrode 3 by the fixing tape 7.

[0018] The lead 6 has a first bent portion 6b, a second bent portion 6c, and a pull-out hole 6d. The first bent portion 6b is the furthest forward bent portion among the multiple bent portions. The second bent portion 6c is the next bent portion located towards the tip after the first bent portion 6b. The pull-out hole 6d is located in the portion between the first bent portion 6b and the tip portion 6a. The pull-out hole 6d is a hole into which the jig 20 is hooked when pulling out the lead 6. As shown in Figures 3 and 4, the lead 6 is connected to the electrode terminal 5 inside the electrode cover 12 when it is pulled out from the opening 11a of the outer cylinder 11. When the lead 6 is bent sequentially from the tip side, the first bent portion 6b becomes the first bent portion, and the second bent portion 6c becomes the second bent portion. Alternatively, if the lead 6 is bent sequentially from the base end, the second bent portion 6c becomes the first bent portion, and the first bent portion 6b becomes the second bent portion.

[0019] As shown in Figures 3 and 4, the outer cylinder 11 is provided with openings 11a at positions corresponding to a pair of electrodes 3. An electrode cover 12 is integrated with the outer cylinder 11 so as to cover the openings 11a of the outer cylinder 11. The electrode cover 12 forms an electrode chamber that houses the pair of electrodes 3. Inside this electrode chamber, the tip of the lead 6 is connected to the electrode terminal 5. The electrode terminal 5 is electrically connected to the electrode 3 via the lead 6. The method of connecting the electrode terminal 5 and the lead 6 is not particularly limited and can be screw fastening or welding.

[0020] The fixing tape 7 is a component that holds the lead 6. The fixing tape 7 is provided with a window portion 7a. When the folded lead 6 is held by the fixing tape 7, the window portion 7a is provided to allow the pull-out hole 6d to be seen. As shown in Figure 7(a), the window portion 7a opens to an opening width W1 in the width direction and to a predetermined length in the length direction.

[0021] The opening width W1 of the window portion 7a is narrower than the width of the lead 6. For example, the opening width W1 is set to be less than or equal to the width of the lead 6 minus 4 mm, and greater than or equal to a predetermined value. This predetermined value is set to be the same as the opening width of the pull-out hole 6d, for example. That is, the width of the lead 6 is formed to be at least 2 mm wider on both sides of the opening width of the pull-out hole 6d. In addition, the width W2 of the fixing tape 7 is formed to be greater than or equal to the width of the lead 6. In this case, the window portion 7a exposes the pull-out hole 6d, and the fixing tape 7 is configured to hold down at least 2 mm of each end of the lead 6 in the width direction. In the width direction of the lead 6, the fixing tape 7 is positioned to cover both ends of the lead 6 in the width direction, and the window portion 7a exposes the center of the lead 6 in the width direction. Because the width W2 of the fixing tape 7 is greater than or equal to the width of the lead 6, when the lead 6 is pulled out from the window portion 7a, the fixing tape 7 deforms to escape outward in the width direction, preventing the fixing tape 7 from breaking.

[0022] The opening length of window 7a is longer than the bent length of lead 6. The bent length of lead 6 is the longer of the length from tip 6a to the first bent portion 6b and the length from the first bent portion 6b to the second bent portion 6c. The opening length of window 7a is longer than the distance between the multiple bent portions of lead 6. Window 7a is positioned so as to expose the pull-out hole 6d, and both ends of lead 6 in the longitudinal direction are contained within window 7a. Tip 6a and the first bent portion 6b are positioned inward from both ends of window 7a in the longitudinal direction.

[0023] A tapered portion 7b is provided in the window portion 7a. The tapered portion 7b forms an opening shape narrower than the opening width W1. The tapered portion 7b is provided on the first bent portion 6b side in the longitudinal direction. The tapered portion 7b is formed such that the opening shape on the first bent portion 6b side gradually narrows compared to the opening shape on the tip portion 6a side. As shown in Figure 1, the fixing tape 7 is attached to the base material 2 such that the tapered portion 7b covers both sides of the first bent portion 6b in the width direction. In the process of pulling the lead 6 out from the window portion 7a, when the tip portion 6a is lifted, the tapered portion 7b presses down on both sides of the first bent portion 6b in the width direction, so that the portion on the tip portion 6a side is pulled out from the window portion 7a so as to rotate with the first bent portion 6b as a pivot point.

[0024] As shown in Figure 7(b), the back surface of the fixing tape 7 is composed of an adhesive portion 7c and a non-adhesive portion 7d. The adhesive portion 7c is provided on both ends of the fixing tape 7 in the longitudinal direction. The non-adhesive portion 7d is formed in the longitudinal direction of the fixing tape 7, including the window portion 7a, and is longer than the bending length of the lead 6. As shown in Figure 1, in the fixing tape 7, the portion placed on the electrode 3 and the portion placed on the lead 6 are composed of the non-adhesive portion 7d. In other words, the adhesive portion 7c is configured not to come into contact with the electrode 3 and the lead 6. Furthermore, as shown in Figure 2, the adhesive portion 7c is applied to the area compressed by the retaining mat 4.

[0025] Here, the manufacturing method of the electric heating catalyst device 1 will be described. The manufacturing method of the electric heating catalyst device 1 includes the steps of fixing the lead 6 with fixing tape 7 (fixing step), pressing the base material 2 into the outer cylinder 11 (press-fitting step), and pulling out the lead 6 from the opening 11a of the outer cylinder 11 (pulling step).

[0026] In the fixing process, the fixing tape 7 is attached to the base material 2 so that the lead 6 is held on the electrode 3 in a folded state multiple times, and the lead 6 is fixed by the fixing tape 7. At this time, the window portion 7a exposes the pull-out hole 6d, and the adhesive portion 7c is attached to the outer surface 2a of the base material 2 so that the entire width and length of the lead 6 is covered with the non-adhesive portion 7d. In other words, the adhesive portion 7c is adhered to the outer surface 2a of the base material 2 without touching the lead 6. The non-adhesive portion 7d is applied to the lead 6. In addition, the fixing tape 7 is applied so that the first bent portion 6b overlaps the tapered portion 7b of the fixing tape 7.

[0027] As the fixing process is performed, the fixing tape 7 is set so that the tip 6a of the lead 6 is located inside the window 7a, and the first bent portion 6b of the lead 6 is positioned over the tapered portion 7b, as shown in Figure 1. Since the fixing tape 7 holds the first bent portion 6b with the tapered portion 7b, the portion that holds the first bent portion 6b is formed to be stronger than the portion that holds the tip 6a. The fixing tape 7 achieves high strength through the opening shape of the window 7a, which includes the tapered portion 7b. Furthermore, as shown in Figure 5, the lead 6 is fixed with the fixing tape 7 so that its height (radial height) when folded is less than or equal to the inner diameter of the outer cylinder 11. For example, the height of the lead 6 when folded is set to 3 mm or less.

[0028] In the press-fitting process, the retaining mat 4 is wrapped around the base material 2 while the lead 6 is held in place by the fixing tape 7. The retaining mat 4 compresses the adhesive portion 7c of the fixing tape 7 and is wrapped around the base material 2 so as to cover both ends of the fixing tape 7 in the longitudinal direction. The retaining mat 4 is wrapped around the base material 2 so that its opening 4a exposes the window portion 7a and covers the surface side of the adhesive portion 7c. As a result, the portion of the fixing tape 7 corresponding to the adhesive portion 7c is sandwiched between the base material 2 and the retaining mat 4. In other words, the adhesive portion 7c is attached to the area compressed by the retaining mat 4. Then, the base material 2 with the retaining mat 4 wrapped around it is press-fitted into the inside of the outer cylinder 11.

[0029] In the pulling process, the lead 6 is pulled out through the window 7a while the fixing tape 7 remains attached to the base material 2. At this time, as shown in Figure 8, the lead 6 is pulled out using a pulling jig 20. The tip of the jig 20 is inserted into the window 7a of the fixing tape 7, and the jig 20 is hooked onto the tip side of the pulling hole 6d.

[0030] Then, as shown in Figure 9, the jig 20 is moved away from the base material 2 to pull the tip 6a of the lead 6 out of the window 7a of the fixing tape 7. When the tip 6a of the lead 6 is pulled out of the window 7a, the portion closer to the tip than the first bent portion 6b is pulled out of the window 7a while the first bent portion 6b remains held in place by the fixing tape 7. By pulling up the tip of the lead 6, the tip 6a of the lead 6 is released from the window 7a, with the first bent portion 6b, which is held in place by the strongly restraining tapered portion 7b, acting as a fulcrum. In addition, the non-adhesive portion 7d is in contact with the lead 6, so the adhesive portion 7c is configured not to apply external force to the lead 6.

[0031] By further lifting the jig 20, the first bent portion 6b also comes out of the window portion 7a, as shown in Figure 10. With the second bent portion 6c still held in place by the fixing tape 7, the portion between the first bent portion 6b and the second bent portion 6c is pulled out of the window portion 7a. In this pulling-out process, the fixing tape 7 does not break, so as shown in Figure 10, the portion from the second bent portion 6c to the first bent portion 6b can be pulled up using the second bent portion 6c as a fulcrum.

[0032] As described above, according to the embodiment, when the base material 2 is press-fitted into the outer cylinder 11, the lead 6 is held in place by the fixing tape 7, thus preventing interference between the lead 6 and the outer cylinder 11. Furthermore, when pulling out the lead 6 from the opening 11a of the outer cylinder 11, the lead 6 can be pulled out from the window portion 7a while the fixing tape 7 is still attached. This makes it easy to pull out the lead 6 after press-fitting. In addition, it prevents the fixing tape 7 from peeling off and coming into contact with the case 10, thus preventing the formation of a leakage path.

[0033] Furthermore, the window portion 7a of the fixing tape 7 is not limited to a shape that includes a tapered portion 7b. For example, as shown in Figure 11(a), a flat portion 7e may be provided on the tip side of the tapered portion 7b. As shown in Figure 11(b), a curved portion 7f may be provided instead of a straight tapered portion 7b. As shown in Figure 11(c), an overlapping portion 7g, where two members are stacked, may be provided at a position corresponding to the tapered portion 7b. The overlapping portion 7g increases rigidity. As shown in Figure 11(d), the entire window portion 7a may be formed in a curved shape. As shown in Figure 11(e), a notch portion 7h may be provided to make it easier to open the window portion 7a. [Explanation of Symbols]

[0034] 1. Electrically heated catalyst device 2 Base material 3 electrodes 4. Retaining mat 5 electrode terminal 6 Lead 7 Fixing tape 10 cases 11 Outer cylinder

Claims

1. A substrate that generates heat when electricity is applied, An electrode attached to the outer surface of the substrate, A thin plate-shaped lead connected to the electrode, An outer cylinder that covers the outer surface of the base material and has an opening for pulling the lead outwards, A retaining mat interposed between the substrate and the outer cylinder to hold the substrate, An electrode terminal is located on the outside of the outer cylinder and is electrically connected to the electrode via the lead, A method for manufacturing an electrically heated catalyst apparatus, comprising the electrodes, wherein the catalyst supported on the substrate is heated via the substrate when a voltage is applied to the substrate by the electrodes, The fixing step involves attaching the fixing tape to the substrate such that the lead is held on the electrode in a folded state multiple times, and a window provided in the fixing tape exposes a part of the lead, thereby fixing the lead with the fixing tape. The press-fitting step involves wrapping the retaining mat around the base material while the lead is held in place by the fixing tape, and then press-fitting the base material together with the retaining mat into the outer cylinder. Subsequently, the lead is pulled out from the window while the fixing tape remains attached to the base material, and the lead is pulled out from the opening of the outer cylinder to the outside of the outer cylinder in a pulling step. A method for manufacturing an electrically heated catalyst device, characterized by including the following:

2. The aforementioned pulling step includes a first step in which, when pulling out the tip of the lead from the window, the portion of the lead beyond the first bent portion that is held in place by the fixing tape, while the first bent portion, which is one of several bent portions that are bent multiple times from the tip to the base of the lead, is pulled out from the window. A method for manufacturing an electrically heated catalyst device according to feature 1.

3. The pulling step includes, after the first step, a second step in which, while the second bent portion, which is located on the tip side after the first bent portion among the plurality of bent portions, is held by the fixing tape, the portion from the first bent portion to the second bent portion is pulled out from the window portion. The method for manufacturing an electrically heated catalyst device according to feature 2.

4. The opening width of the window portion is narrower than the width of the lead. The opening length of the window portion is longer than the distance between the multiple bent portions of the lead. In the width direction of the lead, the fixing tape is positioned to cover both ends of the lead in the width direction, and the window portion is positioned to expose the central part of the lead in the width direction. In the longitudinal direction of the lead, the fixing tape is formed with greater strength in the portion that holds the first bent portion of the lead than in the portion that holds the tip portion of the lead. A method for manufacturing an electrically heated catalyst device according to claim 2 or 3.

5. The fixing tape has a non-adhesive portion that covers the lead and an adhesive portion that is attached to the substrate. The press-fitting step includes wrapping the retaining mat around the substrate such that the retaining mat exposes the window portion of the fixing tape and covers the adhesive portion of the fixing tape. The method for manufacturing an electrically heated catalyst device according to feature 4.

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