Electric circuit and pad constituting electric circuit

Abstract

The operation of connecting the thermocouple wire and the core wire of the compensating lead wire is troublesome and requires a high level of skill for reliable connection. The reliability of the connection portion between the sheath type thermocouple and the compensation lead wire also largely depends on the technique of a person who performs the connection work, and there is also a concern about the reliability.SOLUTION: The electric circuit includes a substrate, a first pad on the substrate, and a wire fixed to the first pad, and includes a first fixed portion that is a portion of the wire fixed to the first pad of the wire by soldering or brazing, and the first pad includes a flat pad formed on a main surface of the substrate and a standing pad standing on the flat pad. According to the electric circuit and the pad constituting the electric circuit of the present invention, it is possible to provide a novel thermocouple wire-compensation lead wire connection structure which can be miniaturized even when the inner diameter of the sleeve is reduced, and in which a short circuit or disconnection of the thermocouple wire is unlikely to occur.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electric circuit in which wires are fixed by pads provided on a substrate, and to a technique for pads that constitute the electric circuit. [Background technology]

[0002] Generally, the measurement value of a sheathed thermocouple is not measured by directly connecting the thermocouple element wire to the measuring instrument, but by connecting it to the measuring instrument via a compensating lead. In other words, a connection between the thermocouple element wire and the compensating lead wire is required, and Figure 11(a) shows a schematic example of this connection state. A sheathed thermocouple is a pair of thermocouple wires (1122) inserted into a metal sheath (1120) filled with heat-resistant insulating powder. The rear ends of the thermocouple wires (1122) are exposed to the outside from the sheath (1120). The compensation lead wire (1140) has a pair of core wires (1142) inserted inside an outer resin sheath, and the front ends of the core wires (1142) are exposed to the outside of the outer resin sheath.

[0003] The rear end of the thermocouple wire (1122) and the front end of the core wire (1142) of the compensation conductor are connected by a ribbon crimper or brazing, although for convenience of explanation, the ribbon crimper and brazing are omitted. A metal sleeve (1130) is placed around the connection between the thermocouple wire (1122) and the core wire (1142) of the compensating conductor, and both ends of this sleeve (1130) are fixed to the sheath (1120) of the sheath-type thermocouple and the outer coating of the compensating conductor (1140), respectively. The inside of the sleeve (1130) is filled with insulating resin, and the connection between the thermocouple wire (1122) and the core wire (1142) of the compensating conductor is buried inside the insulating resin.

[0004] In such a connection device for connecting a sheathed thermocouple to a compensating lead, the connection between the thermocouple element and the core wire of the compensating lead is merely surrounded and held in place by insulating resin, and is not directly fixed or supported rigidly. Therefore, the work of connecting the thermocouple element and the core wire of the compensating lead must be performed in an unstable state in the air, and there is a high risk of bending and disconnecting the thermocouple element and the core wire of the compensating lead. Therefore, the connection work is troublesome and requires high skill to ensure a reliable connection. Furthermore, the reliability of the connection between the sheathed thermocouple and the compensating lead is heavily dependent on the skill of the person performing the connection work, and there are concerns about reliability.

[0005] Furthermore, when connecting thermocouples with small sheath outer diameters, sheathed thermocouples with an outer diameter of 1.5 mm or less (thermocouple wire diameter of 0.1 mm or less), and especially when the sheath outer diameter is 0.5 mm or less (thermocouple wire diameter of 0.08 mm or less), the thermocouple wire can break even with a slight external force during the work, so the connection work requires a fairly high level of skill and concentration, and the reliability of the connection also depends heavily on the work. A technique for solving such problems is known from Patent Document 1.

[0006] The technology of Patent Document 1 will be outlined below with reference to FIG. 9(b). A printed circuit board 3 (connection device) that connects the sheathed thermocouple 1 and the compensation conductors 2A and 2B is housed in a cylindrical metal sleeve 51. The sleeve 51 is arranged concentrically surrounding the printed circuit board 3, and the sheath 11 of the sheathed thermocouple 1 is inserted into a sheath insertion fixing hole 52. The sleeve 51 is brazed to the sheath 11 of the sheathed thermocouple 1.

[0007] The inside of the sleeve 51 is filled with an insulating thermosetting resin 53, such as epoxy resin. The thermosetting resin 53 fills the entire internal space of the sleeve 51 and is fixed to the sheath 11 of the sheath-type thermocouple 1 and the outer coating 21 of the compensation lead wires 2A and 2B, to the rear ends of the thermocouple wires 12A and 12B and the front ends of the core wires 22 of the compensation lead wires, and also to the printed circuit board 3. In this way, the sheath 11, outer coating 21, thermocouple wires 12A and 12B, the core wires 22 of the compensation lead wires, and the sleeve 51 are fixed together.

[0008] A pair of conductor metal layers 31A, 31B are formed side by side in the width direction of the board in the center in the longitudinal direction on one surface 3a of the printed circuit board 3. The pair of conductor metal layers 31A, 31B are formed by the same method as known printed wiring, and have a size necessary for connecting the thermocouple wires 12A, 12B of the sheathed thermocouple 1 and the core wires 22 of the compensation wires 2A, 2B.

[0009] An end of one thermocouple wire 12A of the sheathed thermocouple 1 and an end of the core wire 22 of one compensation conductor 2A are arranged facing each other on one conductive metal layer 31A, and these thermocouple wires 12A and core wires 22 are joined to each other by brazing using a brazing material 4 and are fixed to the conductive metal layer 31A. An end of the other thermocouple wire 12B of the sheathed thermocouple 1 and an end of the core wire 22 of the other compensation conductor 2B are arranged facing each other on the other conductive metal layer 31B, and these thermocouple wires 12B and core wire 22 are joined to each other by brazing using a brazing material 4 and are fixed to the conductive metal layer 31B. A gap is provided in the radial direction of the sleeve 51 so that adjacent rear ends of the pair of thermocouple wires 12A, 12B and adjacent front ends of the pair of core wires 22 do not come into contact with each other. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-166882 Summary of the Invention [Problem to be solved by the invention]

[0011] In this way, according to the technology of Patent Document 1, the thermocouple wires 12A, 12B of the sheathed thermocouple 1 and the core wire 22 of the compensation lead wires 2A, 2B are rigidly and directly fixed and supported, so that both core wires can be easily connected and disconnection of the thermocouple wires 12A, 12B can be prevented during the connecting work. Furthermore, the thermocouple wires 12A, 12B of the sheathed thermocouple 1 and the core wire 22 of the compensation lead wire 2 can be reliably connected, so that accidents such as disconnection or disconnection do not occur when the product (sheathed thermocouple device) is used, thereby improving the reliability of the connection. Furthermore, it is described that the connecting work can be easily and reliably performed particularly when the outer diameter of the sheath 11 of the sheathed thermocouple 1 is 1.5 mm or less (wire diameter 0.1 mm or less), and especially when the outer diameter of the sheath 11 is 0.5 mm or less (wire diameter 0.08 mm or less).

[0012] However, the technology of Patent Document 1 focuses on the outer diameter of the sheath 11 and the diameter of the wire, but does not pay any attention to the outer diameter or inner diameter of the sleeve. Although adjacent pairs of thermocouple wires and core wires are spaced apart in the diametrical direction to prevent contact, it is not possible to prevent short circuits before they are fixed with the thermosetting resin. This problem becomes particularly serious as the outer and inner diameters of the sleeve become smaller. That is, the inventors have completed the present invention based on the recognition that when the sleeve is quite thin, with an outer diameter of φ4 and an inner diameter of φ3.6, short circuits and breakages are still likely to occur even when a glass epoxy substrate is used instead of brazing or a ribbon crimper to connect the thermocouple wires and the core wires of the compensation lead wires, which must be performed in an unstable state in the air. Furthermore, the type K thermocouple wire standardized by JIS is chromel-alumel, which makes it difficult to solder and makes soldering to the compensating wire difficult. [Means for solving the problem]

[0013] In order to solve the above problems, the first invention of the present invention provides an electrical circuit having a substrate, a first pad on the substrate, and a wire rod fixed thereto, wherein the wire rod has a first fixing portion which is a portion fixedly connected to the first pad by soldering or brazing, and the first pad is an electrical circuit consisting of a flat pad formed on the main surface of the substrate and an upright pad erected relative to the flat pad.

[0014] A second aspect of the present invention provides the electric circuit according to the first aspect of the present invention, wherein the upright pads are formed by inserting a substrate on which the upright pads are arranged into a notch provided on the main surface of the substrate.

[0015] Furthermore, a third invention provides an electric circuit according to the first or second invention, further comprising a second pad on the substrate, the wire having a second fixing portion which is fixed to the second pad by soldering or brazing, and the first fixing portion being a portion which is fixedly connected by soldering or brazing to a first pad of the wire which is connected in an almost linear and continuous manner to the wire fixed by the second fixing portion.

[0016] A fourth invention provides the electric circuit according to the third invention, wherein the wire is a metal sheath of a sheathed thermocouple or a sheathed resistance temperature detector.

[0017] The fifth invention provides the electric circuit according to the second invention, in which the electric circuit includes a sheath and a core wire exposed from within the sheath and connected to a first pad, and the sheath is sandwiched between a sheath notch formed by combining a first sheath notch provided on one substrate and a second sheath notch provided on another substrate.

[0018] A sixth invention provides the electric circuit according to the fifth invention, wherein the sheath is a metal sheath of a sheathed thermocouple or a sheathed resistance temperature detector.

[0019] In addition, a seventh invention provides an electric circuit based on the fifth invention, further comprising a second pad on the substrate, the wire having a second fixing portion which is fixed to the second pad by soldering or brazing, and the first fixing portion being a portion which is fixedly connected by soldering or brazing to the first pad of the wire which is connected in an almost linear and continuous manner to the wire fixed by the second fixing portion.

[0020] The eighth invention provides an electric circuit based on any one of the first, fifth, or seventh inventions, in which the substrate has a plurality of main surfaces that form radial apex angles.

[0021] Furthermore, the ninth invention provides a pad that constitutes an electrical circuit for joining wires by soldering or brazing, the pad consisting of a flat pad formed on the main surface of the substrate and an upright pad that is erected relative to the main surface of the substrate.

[0022] The tenth invention provides a pad that constitutes an electrical circuit based on the ninth invention, in which the pad is configured in an L-shape by a flat pad configured on the main surface of the substrate and an upright pad that is configured upright relative to the main surface of the substrate.

[0023] The eleventh invention is a pad that constitutes an electrical circuit based on the ninth invention, in which the pad is U-shaped and is composed of a flat pad formed on the main surface of the substrate and an upright pad that is erected relative to the main surface of the substrate.

[0024] The twelfth invention is a pad that constitutes an electric circuit based on the ninth invention, in which the pad is configured in a V-shape with two standing pads that are erected at the same position on the main surface of the substrate but at different angles relative to the main surface of the substrate.

[0025] A thirteenth aspect of the present invention is a pad constituting an electric circuit based on any one of the ninth to twelfth aspects of the present invention, in which the pad is also formed on another main surface of the substrate. [Effects of the Invention]

[0026] The electric circuit of the present invention and the pad that constitutes the electric circuit can provide a new thermocouple element wire-compensating conductor connection structure that can be made smaller even if the inner diameter of the sleeve is narrowed, and that is less likely to cause short circuits or breaks in the thermocouple element wire. Furthermore, the electric circuit and the pads that make up the electric circuit of the present invention allow for better solder adhesion to the wire than with planar pads, so that even type K thermocouple wire (chromel-alumel) can be suitably soldered to the compensation wire. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is an overall view showing an example of the structure of a sheathed thermocouple unit according to Embodiments 1 to 3. [Figure 2] FIG. 1 is a diagram illustrating an example of the structure of a printed circuit board according to the first and second embodiments. [Figure 3] FIG. 1 is a diagram showing an example of an electric circuit according to the first and second embodiments. [Figure 4] 10A and 10B are diagrams illustrating an example of the structure of a printed circuit board and an example of an electric circuit according to a third embodiment. [Figure 5] 10A and 10B are diagrams illustrating an example of the structure of a printed circuit board and an example of an electric circuit according to a fourth embodiment. [Figure 6] FIG. 10 is a diagram illustrating another example of the structure of the printed circuit board according to the first embodiment. [Figure 7] FIG. 1 is a diagram illustrating an example of the structure of a printed circuit board according to Modification 1. [Figure 8] FIG. 10 is a diagram illustrating an example of the structure of a printed circuit board according to Modification 2. [Figure 9] FIG. 10 is a diagram illustrating an example of the structure of a printed circuit board according to Modification 3. [Figure 10] FIG. 10 is a diagram illustrating an example of the structure of a printed circuit board according to Modification 4. [Figure 11] FIG. 1 is a diagram illustrating an example of a conventional technique. [Explanation of symbols]

[0028] 0110 Sheathed Thermocouple Unit 0120, 1120 sheath 0130, 1130 sleeve 0140, 1140 Compensation conductor 0150 Connector 0160, 0460 Electrical Circuits 0210, 0220, 0230, 410 printed circuit board 0211 Second Pad 0212, 0213 First pad 0222, 0223 Flat Pad 0232,0233 Standing pad 0224, 0234, 415 Cutting 0310, 1122 Thermocouple wire 1142 Core wire DETAILED DESCRIPTION OF THE INVENTION

[0029] The following describes embodiments of each invention. Note that the present invention is not limited to these embodiments in any way, and can be implemented in various forms without departing from the spirit of the invention. The relationship between the following embodiments and claims is as follows: Embodiment 1 mainly describes claims 1, 2, 7, and 8, etc. Embodiment 2 mainly describes claim 3, etc. Embodiment 3 mainly describes claim 5, etc. Embodiment 4 mainly describes claim 7, etc. <Embodiment 1: Inventions Relating to Claims 1, 2, 7, and 8>

[0030] <Concept of First Embodiment> Although a sheathed thermocouple unit will be described as an example of the electric circuit in the first embodiment, it is also applicable to other electric circuits such as a sheathed resistance thermometer unit. As shown in Fig. 1, the sheathed thermocouple unit (0110) in this embodiment is externally composed of four parts: a sheath (0120), a sleeve (0130), a compensation lead wire (0140), and a connector (0150). The electric circuit (0160) is housed in the sleeve (0130).

[0031] As shown in the schematic diagram of FIG. 2, the electric circuit (0160) has first pads (0212, 0213) provided on a printed circuit board (0210). The printed circuit board (0210) is formed by assembling (inserting) a printed circuit board A (0220) and a printed circuit board B (0230). The first pad (0212) consists of a flat pad (0220) provided on the printed circuit board A and an upright pad (0232) provided on the printed circuit board B, and forms a so-called L-shape after assembly. A similar upright pad (0233, not shown) is also provided on the other side of the printed circuit board B, and forms a so-called L-shape together with another flat pad (0223) provided on the printed circuit board A. In the figure, the two flat pads are arranged symmetrically across the printed circuit board, but the position of the first pad is not limited as long as the flat pad and the upright pad form an L-shape.

[0032] <Configuration of First Embodiment> Next, the electric circuit (0160) will be explained with reference to FIG. Here, the rear end of the thermocouple wire (0322) is referred to as a first fixed portion. The two thermocouple wires (0322) exposed from the sheath (0120) are distributed to both sides of the printed circuit board B, and are soldered or brazed approximately parallel along the boundary between the flat pad (0222) (not shown) that forms the first pad (0212) and the standing pad (0232) (not shown), thereby electrically connecting the flat pad (0222), the standing pad (0232), and the first fixed portion of the thermocouple wire (0322). The first fixed portion is then firmly fixed to the printed circuit boards A and B by the molten solder or brazing material. At this time, the core wire (0342) of the compensation lead wire (0140) can also be soldered or brazed at the same time. Similarly, the other thermocouple wires (0322) and the core wires (0342) of the other compensation lead wires (0140) are electrically connected to the other first pads (0213) and firmly fixed to the printed circuit boards A and B.

[0033] The electric circuit (0160) thus created is housed and protected in a sleeve (0130) inserted from the tip of the sheath (0120). The sheath side of the sleeve (0130) is fixed to the sheath (0120) by brazing or the like.

[0034] Next, the standing pads (0232, 0233) will be explained with reference to Figs. For example, as shown in FIG. 6(a), a printed circuit board B having upright pads (0232, 0233) can be placed in the gaps (corresponding to the thickness of the printed circuit board B) between flat pads (0222, 0223) formed on a printed circuit board A to form first pads (0212, 0213). Also, as shown in Figure 6(b), a slit can be provided in the gap (corresponding to the thickness of printed circuit board B) between the planar pads (0222, 0223) configured on printed circuit board A, and printed circuit board B can be inserted into this slit to form the first pads (0212, 0213). Furthermore, preferably, as shown in FIG. 2, notches (0224, 0234) are provided in each of the printed circuit boards A and B, and the notches (0224, 0234) are inserted in a cross shape so as to sandwich the other printed circuit board (0230, 0220), thereby forming first pads (0212, 0213). Of course, these are merely examples and do not preclude other structures. In the first embodiment, a sheathed thermocouple has been described as an example, but the present invention is not limited to a sheathed thermocouple and may be a sheathed resistance temperature detector.

[0035] <Advantages of First Embodiment> As described above, according to the electric circuit of the first embodiment, each of the thermocouple wires can be connected to each of the compensation conductors on both sides of the printed circuit board B in an isolated and insulated state, making it possible to easily prevent short circuits. This is particularly effective for sleeves with small outer and inner diameters. In addition, by making the pads at the connection points three-dimensionally L-shaped, the total area is expanded and the 90-degree pattern is expected to improve soldering or brazing work and prevent breakage. <Embodiment 2: Invention according to claim 3>

[0036] <Concept of the second embodiment> The electric circuit (0160) differs from that of the first embodiment in that a second pad (0211) is provided on the printed circuit board (0210).

[0037] <Configuration of Second Embodiment> Next, the electric circuit (0160) will be explained with reference to FIG. Here, the portion where the sheath (0120) is placed on the second pad (0211) is called the second fixing portion. The second fixing portion of the sheath (0120) is fixed to the second pad (0211) on the printed circuit board A by brazing. The first fixing portion is a portion fixed by soldering or brazing to the first pad (0212) of the thermocouple wire (0322) that is connected in a substantially linear and continuous manner to the sheath (0120) fixed by the second fixing portion. The two thermocouple wires (0322) exposed from inside the sheath (0120) are distributed to both sides of the printed circuit board B, and the flat pad (0222), the standing pad (0232), and the first fixing portions of the thermocouple wire (0322) are electrically connected by soldering or brazing approximately parallel along the boundary between the flat pad (0222) and the standing pad (0232). The first fixing portions are then firmly fixed to the printed circuit boards A and B by molten solder or brazing material. At this time, the core wire (0342) of the compensating conductor (0140) can also be soldered or brazed at the same time. Similarly, the other thermocouple wires (0322) and the core wires (0342) of the other compensating conductors (0140) are electrically connected by other first pads (0213) and are firmly fixed to the printed circuit boards A and B.

[0038] The electric circuit (0160) thus created is housed and protected in a sleeve (0130) inserted from the tip of the sheath (0120). The sheath side of the sleeve (0130) is fixed to the sheath (0120) by brazing or the like. In the second embodiment, a sheathed thermocouple has been described as an example, but the present invention is not limited to a sheathed thermocouple and may be a sheathed resistance temperature detector.

[0039] <Advantages of the Second Embodiment> As described above, according to the electric circuit of the second embodiment, each of the thermocouple wires can be connected to each of the compensation conductors on both sides of the printed circuit board B in an isolated and insulated state, making it possible to easily prevent short circuits. This is particularly effective for sleeves with small outer and inner diameters. In addition, by making the pads at the connection points three-dimensionally L-shaped, the total area is expanded and the 90-degree pattern is expected to improve soldering or brazing work and prevent breakage. Furthermore, by providing a second pad (0211) that fixes the sheath (0120), the position of the thermocouple wire on the first pad can be stabilized, and the load applied to the thermocouple wire can be reduced, preventing breakage. Also, unevenness in the quality of soldering or brazing to the first pad can be prevented. <Embodiment 3: Claim 5> <Concept of the third embodiment>

[0040] Although a sheathed thermocouple unit will be described as an example of the electric circuit in the third embodiment, it is also applicable to other electric circuits such as a sheathed resistance thermometer unit. The sheathed thermocouple unit (0110) in this embodiment is similar in appearance to that in the first embodiment, and detailed description thereof will be omitted.

[0041] Referring to FIG. 4, the electric circuit (0460) differs from that of the first embodiment in that a notch (0415) is provided in the printed circuit board (0410). The notch (0415) is a space formed by the notch (0425) in the printed circuit board A (0420) and the notch (0435) in the printed circuit board B (0430) when the printed circuit board A (0420) and the printed circuit board B (0430) are assembled (inserted).

[0042] <Configuration of Third Embodiment> Next, the electric circuit (0460) will be explained with reference to FIG. The sheath (0120) is inserted from the open end (right side in Figure 4) into the notch (0415) formed in the printed circuit board (0410), and is held on all sides by printed circuit boards A and B. The two thermocouple wires (0322) (not shown) exposed from inside the sheath (0120) are distributed to both sides of the printed circuit board B, and are soldered or brazed approximately parallel along the boundary between the flat pad (0222) and the standing pad (0232), electrically connecting the flat pad (0222), the standing pad (0232), and the thermocouple wire (0322) (not shown), and the molten solder or brazing material firmly fixes the connection to the printed circuit boards A and B. At this time, the core wire (0342) (not shown) of the compensation conductor (0140) can also be soldered or brazed at the same time. Similarly, other thermocouple wires (0322) (not shown) and core wires (0342) (not shown) of other compensation conductors (0140) are electrically connected to other first pads (0213) (not shown) and are firmly fixed to printed circuit boards A and B.

[0043] The electric circuit (0460) thus created is housed and protected in a sleeve (0130) inserted from the tip of the sheath (0120). The sheath side of the sleeve (0130) is fixed to the sheath (0120) by brazing or the like. In the third embodiment, a sheathed thermocouple has been described as an example, but the present invention is not limited to a sheathed thermocouple, and a sheathed resistance temperature detector may also be used.

[0044] <Advantages of the Third Embodiment> As described above, according to the electric circuit of the third embodiment, each of the thermocouple wires can be connected to each of the compensation conductors on both sides of the printed circuit board B in an isolated and insulated state, making it possible to easily prevent short circuits. This is particularly effective for sleeves with small outer and inner diameters. In addition, by making the pads at the connection points three-dimensionally L-shaped, the total area is expanded and the 90-degree pattern is expected to improve soldering or brazing work and prevent breakage. Furthermore, by forming the space (notch 415) for holding the sheath (0120) by the notch (0425) in the printed circuit board A (0420) and the notch (0435) in the printed circuit board B (0430), the position of the thermocouple wire on the first pad can be stabilized, thereby preventing uneven quality of soldering or brazing to the first pad. Furthermore, by aligning the central axis position of the space formed by the notch (0415) with the level of the flat pads (0222) and (0223), it is possible to accommodate a smaller diameter sleeve (0130). <Embodiment 4: Invention according to claim 7> <Concept of the fourth embodiment> The electric circuit (0560) differs from that of the third embodiment in that second pads (0511) are provided on the printed circuit board (0510) along the notches (0415).

[0045] <Configuration of Fourth Embodiment> Next, the electric circuit (0560) will be explained with reference to FIG. Here, the portion of the sheath (0120) that is in contact with or close to the second pad (0511) is called the second fixing portion. The second fixing portion of the sheath (0120) is fixed by brazing to the second pad (0511) on the printed circuit board A. The first fixing portion is a portion that is fixed by soldering or brazing to the first pad (0212) of the thermocouple wire (0322) (not shown) that is connected in an almost linear and continuous manner to the sheath (0120) fixed by the second fixing portion. The two thermocouple wires (0322) (not shown) exposed from inside the sheath (0120) are distributed to both sides of the printed circuit board B, and the flat pad (0222) (not shown) and the standing pad (0232) (not shown) that form the first pad (0212) are soldered or brazed almost parallel to each other along the boundary line between them, thereby electrically connecting the flat pad (0222), the standing pad (0232), and the first fixing portion of the thermocouple wire (0322) (not shown). The first fixing portions are then firmly fixed to the printed circuit boards A and B by molten solder or brazing material. At this time, the core wires (0342) (not shown) of the compensating conductors (0140) can also be soldered or brazed at the same time. Similarly, the other thermocouple wires (0322) and the core wires (0342) (not shown) of the other compensating conductors (0140) are electrically connected to other first pads (0213) (not shown) and are firmly fixed to the printed circuit boards A and B.

[0046] The electric circuit (0560) thus created is housed and protected in a sleeve (0130) inserted from the tip of the sheath (0120). The sheath side of the sleeve (0130) is fixed to the sheath (0120) by brazing or the like. In the third embodiment, a sheathed thermocouple has been described as an example, but the present invention is not limited to a sheathed thermocouple, and a sheathed resistance temperature detector may also be used.

[0047] <Advantages of the Fourth Embodiment> As described above, according to the electric circuit of the second embodiment, each of the thermocouple wires can be connected to each of the compensation conductors on both sides of the printed circuit board B in an isolated and insulated state, making it possible to easily prevent short circuits. This is particularly effective for sleeves with small outer and inner diameters. In addition, by making the pads at the connection points three-dimensionally L-shaped, the total area is expanded and the 90-degree pattern is expected to improve soldering or brazing work and prevent breakage. Furthermore, by providing the second pad (0511) for fixing the sheath (0120), the position of the thermocouple wire on the first pad can be stabilized, and the load applied to the thermocouple wire can be reduced, preventing breakage. Also, unevenness in the quality of soldering or brazing to the first pad can be prevented. It goes without saying that the positions and number of the second pads (0511) provided on the printed circuit board (0510) can be determined as appropriate. For example, they may be provided in a total of eight locations, or in four locations forming opposite angles.

[0048] <Variation 1> <Configuration of Modification 1> In the first embodiment, a single printed circuit board B is combined with the printed circuit board A. However, in the first modification, as shown in FIG. 7, multiple notches can be prepared in the printed circuit board A, and a printed circuit board B can be combined with each of them. In this case, two upright pads contact the flat pad of the printed circuit board A between adjacent printed circuit boards B, forming a U-shaped connection pad. This makes it possible to provide an electrical circuit that can accommodate, for example, a three-wire sheathed resistance thermometer sensor, and has a wide range of applications.

[0049] <Variation 2> <Configuration of Modification 2> In the first modification, a plurality of cuts are prepared in the printed circuit board A in a substantially parallel manner, and the printed circuit board B is combined with each of the cuts to form U-shaped connection pads. In Variation 2, as shown in Figure 8, two notches are provided on the same line on both sides of printed circuit board A, and printed circuit boards B1 and B2 are attached to each notch so that they form an acute angle with the main surface of board A. In this case, two upstanding pads on each of adjacent printed circuit boards B1 and B2 contact each other, forming a V-shaped connection pad. This allows for the provision of an electrical circuit compatible with, for example, a three-wire sheathed resistance thermometer, which has a wide range of applications. Since the number of printed circuit boards B is not limited to two, it is also possible to accommodate a multi-wire sheathed resistance thermometer.

[0050] <Variation 3> <Configuration of Modification 3> In the third embodiment, the flat pads are provided on the top surface of the printed circuit board A, but in the third modification, a flat pad is also provided on the bottom surface. Furthermore, printed circuit board B is also provided with standing pads at positions corresponding to the flat pads on the bottom surface. In other words, as shown schematically in FIG. 9, four L-shaped connection pads are formed at 90-degree intervals. This makes it possible to provide an electric circuit that can accommodate, for example, a two-pair two-wire sheathed thermocouple or a four-wire sheathed resistance thermometer, and has a wide range of applications. This configuration can be applied not only to the first, second, and third embodiments but also to the above-mentioned first and second modifications. This is expected to enable further favorable compatibility with multi-wire sheathed resistance thermometer sensors.

[0051] <Variation 4> In the first embodiment, both printed circuit boards A and B are flat plates, and printed circuit board A has two parallel main surfaces, i.e., a front and a back. In the fourth modification, as shown in FIG. 10(a), one main surface of printed circuit board A has a bent portion at an approximately 120° angle, and two radial surfaces with the bent portion forming an approximate apex angle. Planar pads are formed on the main surfaces of the Y-shaped printed circuit board having three bent main surfaces. Similarly, standing pads are formed on the Y-shaped printed circuit board B. By combining cuts in the Y-shaped printed circuit boards A (1020) and B (1030) with a phase difference of 60 degrees, an electrical circuit with a structure similar to that of the second modification can be provided. FIG. 10(b) is a front view, and FIG. 10(c) is a side view. It goes without saying that the printed circuit boards A and B in Modification 4 are not limited to a Y-shape and may be cross-shaped. Furthermore, this does not preclude combination with the configurations of Modifications 2 and 3.

Claims

1. An electric circuit having a substrate, a first pad on the substrate, and a wire fixed thereto, the wire has a first fixing portion which is a portion fixedly connected to the first pad by soldering or brazing, The first pad is an electric circuit made up of a flat pad formed on the main surface of the substrate and an upright pad provided upright relative to the flat pad.

2. 2. The electric circuit according to claim 1, wherein the upstanding pads are formed by inserting a substrate on which the upstanding pads are arranged into a notch provided on the main surface of the substrate.

3. further comprising a second pad on the substrate; the wire has a second fixing portion that is fixed to the second pad by soldering or brazing, 3. The electrical circuit according to claim 1, wherein the first fixing portion is a portion that is fixedly connected by soldering or brazing to a first pad of a wire that is connected in an approximately linear and continuous manner to the wire fixed by the second fixing portion.

4. 4. The electric circuit according to claim 3, wherein the wire is a metal sheath of a sheathed thermocouple or a sheathed resistance temperature detector.

5. 3. The electrical circuit according to claim 2, wherein the electrical circuit includes a sheath and a core wire exposed from the sheath and connected to a first pad, and the sheath is sandwiched between a sheath notch formed by combining a first sheath notch provided on one substrate and a second sheath notch provided on another substrate.

6. 6. The electric circuit according to claim 5, wherein the sheath is a metal sheath of a sheathed thermocouple or a sheathed resistance temperature detector.

7. further comprising a second pad on the substrate; the wire has a second fixing portion that is fixed to the second pad by soldering or brazing, 6. The electric circuit according to claim 5, wherein the first fixing portion is a portion that is fixedly connected by soldering or brazing to a first pad of a wire that is connected in an approximately linear and continuous manner to the wire fixed by the second fixing portion.

8. 8. The electric circuit according to claim 1, wherein the substrate has a plurality of principal surfaces that form radial apex angles.

9. Pads that form an electric circuit for joining wires by soldering or brazing, consisting of flat pads formed on the main surface of the substrate and standing pads that are erected on the main surface of the substrate.

10. 10. The pads constituting an electric circuit according to claim 9, wherein the pads are configured in an L-shape by a flat pad formed on the main surface of the substrate and an upstanding pad provided upright relative to the main surface of the substrate.

11. 10. The pad constituting an electric circuit according to claim 9, wherein the pad is configured in a U-shape by a flat pad formed on the main surface of the substrate and an upstanding pad provided upright relative to the main surface of the substrate.

12. 10. The pad constituting an electric circuit according to claim 9, wherein the pad is configured in a V-shape by two standing pads that are erected at the same position on the main surface of the substrate at different angles relative to the main surface of the substrate.

13. 13. The pad constituting the electric circuit according to claim 9, wherein the pad is also formed on another main surface of the substrate.

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