JP2001311717A - Lead wire connection structure of sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead wire connection structure of a sensor in which disconnection of an element side lead wire seldom occurs. SOLUTION: End parts of two element side lead wires 12, 12 drawn out from a temperature sensing element 2 (detection element) are jointed and stuck respectively by spot welding or the like corresponding to polarities on each element side connection part 72, 82 forming respectively a part of each body part 71, 81 of a plus side electrode plate 7 (junction part) and a minus side electrode plate 8 (junction part). One end parts of two harness side lead wires 13, 13 are connected and fixed respectively by joint terminals 14, 14 to each harness side connection part 73, 83 of the electrode plates 7, 8, and the other end parts of the harness side lead wires 13, 13 are elongated to the outside of the sensor 1 through an opening 11 on the rear end of a second external cylinder 11 (cylindrical part). Hereby the element side lead wires 12, 12 are connected indirectly to the harness side lead wires 13, 13 through the electrode plates 7, 8, and an external force applied on the harness side lead wires 13, 13 in the axis direction is hardly transmitted directly to the element side lead wires 12, and therefore disconnection of the element side lead wires 12 seldom occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor lead wire connecting structure using various detecting elements, such as a temperature sensing element of a temperature sensor and a gas detecting element of a gas sensor.

[0002]

2. Description of the Related Art Conventionally, in a temperature sensor or a gas sensor provided with a detecting element having, for example, a rectangular cross section (a so-called plate shape), an element-side lead wire extending from the detecting element is provided;
The harness-side lead wire extending outside the sensor (cylindrical portion) is directly connected to the joint terminal by caulking or resistance welding.

[0003]

In the case where the element-side lead wire and the harness-side lead wire are directly connected simply by swaging a joint terminal or by resistance welding, the lead wire on the harness-side is connected to the lead wire on the harness side. The applied external force may be directly transmitted to the element-side lead wire, which may lead to disconnection of the element-side lead wire. For example, in a Pt resistor temperature sensor for measuring the exhaust temperature of an engine, the element-side lead wire has a very small wire diameter and is weak in tensile force, so that vibrations of the engine during measurement are transmitted to the element-side lead wire and are disconnected. Sometimes.
In connecting the element-side lead and the harness-side lead during the assembly of the temperature sensor, the element-side lead may be pulled by the harness-side lead and may be disconnected.

It is an object of the present invention to provide a sensor lead wire connection structure in which disconnection of an element-side lead wire hardly occurs.

[0005]

Means for Solving the Problems and Action / Effects In order to solve the above problems, a sensor lead wire connection structure (hereinafter, also simply referred to as a connection structure) according to the present invention has a cylindrical shape having an opening at at least one end. A detection element is arranged inside the portion, an element-side lead wire extending from the detection element, and a harness-side lead wire extending outside the cylindrical portion through the opening, While being held inside the cylindrical portion in a form in which movement in the axial direction is restricted, it is connected to the cylindrical portion via a conductive relay portion which is held in an electrically insulated state. It is characterized by being.

According to the above invention, the element-side lead wire and the harness-side lead wire are held inside the tubular portion in such a manner that the movement of the tubular portion in the axial direction is restricted, and the tubular portion is Are connected to each other via a conductive relay section which is held in an electrically insulated state. This makes it difficult for the external force applied to the harness-side lead wire in the axial direction when the sensor is used to be directly transmitted to the element-side lead wire, and the disconnection of the element-side lead wire is less likely to occur. Also,
If the element side lead wire and the harness side lead wire are connected to the relay section in different steps at different positions during assembly of the sensor, the element side lead wire is pulled by the harness side lead wire during assembly and is disconnected. Can also be effectively prevented. For example, in the case of an element-side lead wire used for a normal on-vehicle temperature sensor, the tensile strength is 68.6 Nｋｇ7 kg.
Those of f｝ to 98 N {10 kgf} are generally used. The present invention can exert a remarkable effect on an element-side lead wire having a tensile strength equal to or less than these values.

The relay portion is held in the cylindrical portion in an electrically insulated state by an insulating support member disposed inside the cylindrical portion, so that the relay portion extends in the axial direction of the cylindrical portion. The movement of the lead is reliably held inside the cylindrical portion in a form in which the movement is restricted, and it has a remarkable effect in preventing disconnection of the element-side lead wire. Specifically, it is preferable that the support member be held so as to sandwich the relay section from both sides in the axial direction of the tubular section.

Further, the support member is provided with an engagement portion for restricting the movement of the relay portion in a direction intersecting with the axis of the cylindrical portion, so that the relay portion moves in a direction intersecting with the axis of the cylindrical portion. Also in this case, the movement can be limited to a predetermined range, and disconnection of the element-side lead wire can be prevented. Specifically, the engaging portion provided on the support member is formed in a concave portion or a protruding portion, while the relay portion is formed with a relay portion-side protruding portion or a relay portion-side concave portion in a form corresponding to such an engaging portion. can do. Further, the engagement portion provided on the support member may be provided upright in a wall shape in the axial direction of the cylindrical portion, and may be arranged so as to be able to abut against the peripheral edge or the outer peripheral surface of the relay portion.

At this time, the relay portion has a main body portion held in an electrically insulated state with respect to the cylindrical portion, and an element side connection portion provided on the main body portion and connected to an element side lead wire. When the main body portion has a harness side connection portion to which the harness side lead wire is connected, the element side lead wire and the harness side lead wire are connected to the respective connection portions of the relay portion at separate positions separated from each other. it can. That is, at the time of use and assembly of the sensor, the external force applied to the harness-side lead hardly acts on the element-side lead, and the disconnection of the element-side lead further hardly occurs. Further, when the plate-shaped main body portion of the relay portion is disposed in a direction intersecting with the axis of the cylindrical portion, and when the support member is disposed inside the cylindrical portion so as to sandwich both end surfaces of the main body portion, the cylindrical shape is used. The relay portion (the main body portion) can be compactly and reliably held inside the tubular portion in a form in which the movement of the portion in the axial direction is restricted.

[0010] At least one of the element-side connection portion and the harness-side connection portion of the relay portion may be formed integrally with the main body portion or may be formed so as to form a part of the main body portion. Since the lead connection structure is simplified, a compact sensor can be obtained.

Next, the element-side lead wire extends from the rear end of the detection element, with the side facing the opening in the axial direction of the cylindrical portion as the rear side, and the element side of the relay section corresponding to this rear end. While the connection portion is provided, a harness-side lead wire is connected to a harness-side connection portion that stands upright from the main body of the relay portion on the rear side. The connection position of the element-side lead wire (the position of the element-side connection portion of the relay section) is close to the position of the rear end of the detection element, and the connection position of the harness-side lead wire (the harness side of the relay section) (The position of the connection portion) can be set at a position distant from the connection portion, so that the work of connecting the element-side lead wire can be performed efficiently.

[0012]

Embodiments of the present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 shows an embodiment of a Pt resistor temperature sensor 1 constituted by using the lead wire connection structure of the present invention, which is used for detecting the temperature of exhaust gas discharged from an internal combustion engine such as an automobile. Can be This resistor temperature sensor 1 measures the temperature of exhaust gas using the property that the electrical resistance of a resistor made of Pt in the temperature-sensitive element 2 increases as the temperature rises, and is chemically stable and long. There is a feature that it can withstand use for a period. The temperature sensing element 2 may be manufactured by a winding method in which a Pt wire is wound around mica or glass, or a thin film forming method by vapor deposition / sputtering of Pt.
A thick film forming method by paste screen printing and firing of the laminated molded body was adopted. In this method, for example, a temperature measuring resistor pattern is formed on one surface of an insulating ceramic (for example, alumina-based ceramic mainly composed of alumina) molded body by screen printing or the like using a Pt paste. Then, another insulating ceramic molded body is laminated and pressed on the printed surface, and the laminated molded body in which the resistance temperature sensor pattern is embedded is fired, whereby the temperature-sensitive element 2 is obtained.

An elongated (so-called plate-shaped) temperature sensing element 2 (detection element) having a rectangular cross section manufactured in this manner.
However, in FIG. 1, it is fixed in a shaft-shaped insertion hole 31 provided inside the cylindrical metal shell 3. Then, the mounting screw 3a formed on the outer peripheral surface of the metal shell 3
The detector D on the tip side of the temperature sensing element 2 is mounted so as to be located in the exhaust pipe, and is exposed to high-temperature exhaust gas flowing in the exhaust pipe. The metal shell 3 is formed with a flange 3c having a hexagonal cross section and having a predetermined width and protruding from the outer peripheral surface at an intermediate portion in the axial direction of the insertion hole 31 in the axial direction.
Therefore, when a tool such as a wrench is fitted and rotated in the flange 3c, the temperature sensor 1 is attached to a predetermined position in the exhaust pipe by the attachment screw 3a via the gasket 3b.

In the following description, the side protruding from the metal shell 3 in the axial direction (longitudinal direction) of the temperature sensing element 2 is referred to as “front side (or tip side)”, and the opposite side is referred to as “rear side (or end side)”. (Rear end side). "

The temperature sensing element 2 inserted into the insertion hole 31 formed in the metal shell 3 is supported by the buffer layer 32. The buffer layer 32 is formed by alternately stacking a powder compact or a porous calcined body of an inorganic material powder such as a talc (talc) ring 33 and a ceramic sleeve 34 in the axial direction alternately. Is supported so as to be wrapped from the outside, and plays a role of suppressing excessive bending stress and thermal stress from being applied to the temperature-sensitive element 2. A caulking packing 35 is provided on the front side of the buffer layer 32 at a position corresponding to the front end of the flange 3 c of the insertion hole 31.
(For example, made of stainless steel) and the buffer layer 3
A cylindrical caulking ring 36 (for example, made of stainless steel) is mounted on the rear side of 2. Caulking ring 3
The rear end annular portion 6 and the rear end annular portion of the metal shell 3 are swaged radially inward to position and hold the temperature sensing element 2 in the axial direction.

As described above, the temperature-sensitive element 2 includes the buffer layer 3
2 and the caulking ring 36, the detecting portion D on the tip side
The metal shell 3 is fixed in the metal shell 3 so as to protrude from the tip of the metal shell 3 fixed to the exhaust pipe. Tip 3d of metallic shell 3
A metal (for example, stainless steel) protection cover 4 that covers the protruding portion of the temperature sensing element 2 is provided on the outer periphery by laser welding or resistance welding (for example, spot welding).
And so on. The cover 4 has a cap shape, and has openings 4a and 4b formed at its tip and at its periphery for guiding high-temperature exhaust gas flowing through the exhaust pipe into the cover 4. On the other hand, the rear end of the metal shell 3 is inserted into the inside of the front end of the first outer cylinder 10 (cylindrical part) made of metal (for example, stainless steel).
The rear part of c is inserted inside the tip part of the second outer cylinder 11 (cylindrical part) also made of metal (for example, stainless steel), and laser welding or resistance welding (for example, spot welding) at each overlapping part. It is joined to each other by, for example, to ensure airtightness.

Inside the first outer cylinder 10, a front support 5 (support member) made of an insulating ceramic (for example, an alumina-based ceramic mainly composed of alumina) divided into two parts in the axial direction and a rear support are provided. The body 6 (support member) is placed on the caulking ring 36. And both supports 5, 6
A predetermined thickness in the axial direction (for example, 0.5 mm)
And the + side electrode plate 7 (relay portion) and the-side electrode plate 8 (relay portion), which are divided in two in the circumferential direction, are sandwiched from both end surfaces in the axial direction. These electrode plates 7, 8
Are positioned in such a manner that the movement of the temperature sensor 1 (first outer cylinder 10) in the axial direction is restricted, and the position is maintained while maintaining the electrical insulation between each other and the first outer cylinder 10 respectively. Will be retained. Each of the electrode plates 7 and 8 has a main body 71, 81 formed in a radial direction (a direction intersecting with the axis of the first outer cylinder 10), and a part of the rear end face of the main body 71, 81 is connected to the element side. The connecting portions 72 and 82 are formed, and the harness-side connecting portions 73 and 83 are formed on the rear side in the axial direction by rising from the main body portions 71 and 81. Therefore,
The electrode plates 7 and 8 are securely fixed to the first outer cylinder 10 by sandwiching the front and rear end surfaces of the main body portions 71 and 81 from both sides by the support members 5 and 6. An element insertion hole 51 through which the temperature sensing element 2 is inserted is formed in the front support 5 so as to penetrate in the axial direction, while the rear support 6 is provided with harness side connection portions 73 and 83 of the electrode plates 7 and 8. Harness side connection part insertion hole 6 to be inserted
1, 61 are formed penetrating in the axial direction.

Further, the device-side lead wires 12 and 12 (for example, made of Pt-Rh) which are electrically connected to the temperature measuring resistor of the temperature sensing device 2;
Wire diameter 0.2-0.3mmφ; Tensile strength 9.8N@1kg
f｝ to 29.4 N {3 kgf} are resistance welded (for example, spot welded) or brazed to the element side connection portions 72, 82 (which constitute a part of the main body portions 71, 81) of the electrode plates 7, 8. And so on. Also, the second outer cylinder 11
The harness-side lead wires 13, 13 extending to the outside of the sensor 1 through the rear end opening 11 are connected to the harness-side connection portion 7.
3 and 83 are connected by joint terminals 14 and 14, respectively. Reference numeral 15 denotes a harness-side lead wire 1 extending outward through an opening 111 at the rear end of the second outer cylinder 11.
This is a separator (for example, made of polytetrafluoroethylene (PTFE) resin) formed to penetrate in the axial direction through separator-side insertion holes 151 and 151 that accommodate the joint terminals 3 and 13 and the joint terminals 14 and 14. Also, 16 is formed by penetrating the harness-side lead wires 13, 13 in the axial direction through the harness-side lead wire insertion holes 161, 161.
A grommet (for example, made of silicon rubber or fluorine rubber) for maintaining the airtightness of the opening 111 so that water and the like do not enter from the opening 111 to short-circuit the sensor 1.
Furthermore, the rear end portion of the first outer cylinder 10 is radially inwardly crimped via the crimping packing 9 to position and hold the rear support 6 (further, the electrode plates 7, 8 and the front support 5) in the axial direction. are doing.

FIG. 2 shows the structure and development of the electrode plate. The electrode plates (relay portions) are point-symmetric with each other on a plan view, and are divided into two in the circumferential direction.
Consists of Conductive metal sheet (for example, 0.5 m thick
m, a stainless steel plate) as shown in the development of FIG.
2 and 82) and the harness-side connecting portions 73 and 83 and the projecting portions 74, 74, 84, and 84, which are integrally formed, are subjected to bending, respectively, so that the respective electrode plates 7, 8 in FIG. Is obtained. Specifically, at the time of punching, the shape is continuous with each extension portion that protrudes outward in the radial direction from the outer peripheral edge of the curved portion of the arcuate or semicircular main body portion 71, 81 in advance, and extends radially inward. Nearly parallel straight cuts 73 'in the book,
83 'is provided. Each claw-shaped portion formed inside these cuts 73 ′, 83 ′ is substantially 9
It is bent in a state of causing 0 °, and the elongated harness side connection portions 73 and 83 are formed. On the other hand, at the time of punching, two substantially parallel linear cuts 7 are formed in advance from the outer peripheral edges of the curved portions of the main body portions 71 and 81 to the inside in the radial direction.
4 ', 74', 84 ', 84' are provided. Each claw portion formed inside these cuts 74 ′, 74 ′, 84 ′, 84 ′ is bent in a state in which it is caused in a direction substantially opposite to the harness side connection portions 73, 83, and the projections 74, 84, 84 ′ are formed.
74, 84, 84 are formed. The protrusion 7
4, 74, 84, 84 cuts 74 ', 74', 8
4 ′, 84 ′, two main body parts 7 in a plan view.
The inclination angles (hereinafter simply referred to as plane inclination angles) with respect to the center line L located between 1 and 81 are each set to 30 °. On the other hand, with respect to the cuts 73 'and 83' of the harness side connection portions 73 and 83, the plane inclination angles are set to 60 degrees. Also, two electrode plates 7, 8
Is formed such that each curved portion forms a part of the circumference when the arc-shaped linear portions are arranged to face each other in plan view.

Therefore, the bent electrode plates 7, 8
When the front and rear end surfaces of the main body portions 71 and 81 are arranged in a direction substantially orthogonal to the axis of the sensor 1 (the first outer cylinder 10), the harness side connection portions 73 and 83 protrude rearward in the axial direction. Harness side connection portion insertion holes 61, 6 of rear support 6
1 (see FIG. 1), while one protrusion 74, 74, 8
Reference numerals 4 and 84 protrude forward in the axial direction and are inserted into recesses (described later) of the front support 5. The number of divisions of the electrode plates 7 and 8 in the circumferential direction is set according to the number of lead wires (element-side lead wires 12 or harness-side lead wires 13) to be connected.

Next, FIG. 3 shows the structure of the front support, and FIG. 4 shows the structure of the rear support. The front support 5 has a cylindrical front portion 52 on the front side and a flange portion 53 having an outer diameter larger than the front portion 52 on the rear side, and the front portion 52 and the flange portion 53 are continuous in the axial direction. And are integrally formed. Element insertion hole 51 having a rectangular cross section for inserting temperature sensing element 2
Are formed through the front part 52 and the flange part 53 including the central axis of the front support 5. The rear end face of the flange portion 53 has a diameter continuous with the element insertion hole 51 in a form continuous with the long side in a cross section of the element insertion hole 51 (a cross section orthogonal to the axis of the element insertion hole 51). A bulging portion 54 (engaging portion) is formed on both sides in the direction.
The bulge 54 is placed on the rear end face of the flange 53 +
The function of holding the side electrode plate 7 and the − side electrode plate 8 at predetermined positions while ensuring an electrical insulation state between them.
In other words, the bulging portion 54 is erected in a wall shape in the axial direction of the sensor 1 and is arranged so as to be able to abut against the peripheral edge or the outer peripheral surface of the electrode plates 7, 8. Sensor 1
Is restricted in the direction intersecting the axis.

The flange 53 has four recesses 55 (engagement portions) of a predetermined depth from the rear end to the front side with a plane inclination angle of 30 ° (two for each of the electrode plates 7, 8). )
Is formed. The recess 55 is provided with the above-described electrode plates 7 and 8.
Are provided so as to correspond to the positions of the protrusions 74, 74 and 84, 84 of the electrode plates 7, 8,
It serves to limit the movement of the (first outer cylinder 10) in the direction intersecting the axis.

On the other hand, the rear support 6 has a pillar-shaped main part 62 on the front side and a rear part 63 having an outer diameter smaller than the main part 62 on the rear side, and the main part 62 and the rear part 63 are arranged in the axial direction. It is formed integrally in a continuous form. A harness-side connecting portion insertion hole 61 having a substantially circular cross section for inserting the harness-side connecting portions 73 and 83 of the electrode plates 7 and 8 penetrates the main body portion 62 and the rear portion 63 and has a plane inclination angle of 60 °. Two are formed. On the front end face of the main body 62, a rear end of the temperature-sensitive element 2 and a housing hole 64 for housing the element-side lead wires 12, 12 drawn from the temperature-sensitive element 2, form a central axis of the rear support 6. It is formed over a predetermined depth toward the rear side in the axial direction. Further, a groove 65 is formed on the front end face of the main body 62 in a form continuous with the opening edge of the accommodation hole 64 and is continuous with both sides in the radial direction with the accommodation hole 64 interposed therebetween. The bulges 54 of the support 5 are associated with each other so as to enter.

Next, FIG. 5A is a perspective view showing a connection form between the element side lead wire and the harness side lead wire with respect to the electrode plate. Each of the element-side connection portions 72 and 82 of the + side electrode plate 7 and the − side electrode plate 8 has the 2
The ends of the element-side lead wires 12, 12 are joined and fixed to each other by spot welding or the like in correspondence with the polarities. On the other hand, one end portion of the two harness-side lead wires 13, 13 is provided at each of the harness-side connection portions 73, 83 of the electrode plates 7, 8, which are bent at approximately 90 ° from the main body portions 71, 81. Are joint terminals 14,
The connection is fixed by 14. The other ends of the harness-side lead wires 13, 13 extend outside the sensor 1 through the opening 11 at the rear end of the second outer cylinder 11. Thus, the element-side lead wires 12 and 12 and the harness-side lead wire 1
3 and 13 are indirectly connected via the electrode plates 7 and 8, and an external force applied in the axial direction to the harness-side leads 13 and 13 is directly applied to the element-side leads 12 and 13.
12 is hardly transmitted to the element-side lead wires 12 and 1.
2 is less likely to break. In addition, as mentioned above,
The plane inclination angle of each of the harness side connection portions 73 and 83 is 6
Since it is set to 0 °, the degree of freedom of the bonding position of the element-side lead wires 12, 12 with respect to the main bodies 71, 81 is greater than in the case of 90 °, and a wider moving space for welding equipment and the like can be secured. There are advantages.

Here, another member (for example, an intermediate member such as a terminal fitting) may be interposed in bonding and fixing the element-side connection portions 72 and 82 and the element-side lead wires 12 and 12. Also, in connecting and fixing the harness-side connection portions 73 and 83 and the harness-side lead wires 13 and 13, other members may be interposed similarly. In any case, the element-side lead wires 12 and 12 and the harness-side lead wires 13 and 13
Since it is connected to the electrode plates 7 and 8 separately and independently at the separated position without fail, the harness-side lead wires 13 and 1 are connected.
3 is applied to the element side lead wire 1 in the axial direction.
It hardly acts on 2,12. Therefore, the probability that the element-side lead wires 12, 12 are disconnected due to engine vibration or the like or during assembly is extremely low, and the reliability of the sensor 1 is improved. The element-side connection portions 72 and 82 of the electrode plates 7 and 8 and the harness-side connection portion 7
By forming the components 3 and 83 integrally with the main bodies 71 and 81, the lead wire connection structure becomes simple, and the sensor 1 can be made compact and compact.

FIG. 5B shows an assembly structure of a front support, a rear support and an electrode plate. The electrode plates 7 and 8 are placed on the rear end surface of the flange 53 of the front support 5, and the bulging portion 54 of the front support 5 enters the groove 65 of the rear support 6 and sandwiches the electrode plates 7 and 8. The two supports 5 and 6 are combined while being held in a state of being held. That is, the rear end face of the flange 53 of the front support 5 and the front end face of the main body 62 of the rear support 6 connect the electrode plates 7, 8 to the plate-shaped main body 7.
Since the electrode plates 1 and 81 are held so as to be sandwiched from both end surfaces in the axial direction, the electrode plates 7 and 8 are moved in the axial direction of the temperature sensor 1 (first outer cylinder 10) due to engine vibration and the like, and the axial lines are moved. (Direction displacement) in the direction intersecting with the direction can be prevented. Moreover, since the main body portions 71 and 81 are thin plate-shaped, the main body portion 7 is formed by the front support 5 and the rear support 6.
It is easy to pinch the front and rear end surfaces of 1,81. Therefore, since the electrode plates 7 and 8 do not come into contact with each other or the first outer cylinder 10, an electrically insulated state is maintained, and
Since the electrode plates 7 and 8 do not displace, even if an external force is applied to the harness-side lead wires 13 and 13, the element-side lead wires 12 and 12 fixed to the main body portions 71 and 81 can be used.
Is less likely to break.

Further, in the concave portion 55 of the front support member 5, a projecting portion 74 provided on the main body portions 71, 81 of the electrode plates 7, 8 is provided.
74, 84, and 84 are inserted, respectively, to limit the displacement of the electrode plates 7, 8 due to engine vibration or the like. As a result, the electrical insulation between the electrode plates 7 and 8 and between the electrode plates 7 and 8 and the first outer cylinder 10 is more reliably maintained, and the element-side lead wires 12 and 12 may be disconnected. Is also smaller. The protrusions 74, 74, 84,
84 is an element-side connection 72, 82 or a harness-side connection 7
3, 83 can also be provided. At this time, a concave portion is provided on the rear support 6 side, and the body portions 71, 81 of the electrode plates 7, 8 are provided.
Element-side connection portions 72 and 82 or harness-side connection portions 73 and 8
3 may be engaged with the protruding portions 74, 74, 84, 84. Of course, it is also possible to provide a concave portion or a hole on the side of the electrode plates 7 and 8 and provide a protruding portion on the side of the front support 5 or the rear support 6 for engagement.

By the way, as is apparent from FIG.
The rear edge of the temperature sensing element 2 is connected to the main body portions 71, 8 of the electrode plates 7, 8.
1 (that is, the flange 53 of the front support 5).
(The rear end surface of the opening 111). Thereby, on the rear end face of the flange portion 53 of the front support member 5, the rear end protruding portion of the temperature sensing element 2 located at the axial center portion and the bulging portions 54, 54 connected to both sides with the rear portion protruding therebetween.
A strip-shaped isolation wall is formed in such a manner as to be continuously arranged in the radial direction along the body portions 71, 81 of the two electrode plates 7, 8. Therefore, the rear end face of the flange portion 53 is clearly separated and separated by the band-shaped separating wall into a portion where the + side electrode plate 7 is placed and a portion where the − side electrode plate 8 is placed. Therefore, an electrical insulation state between the electrode plates 7 and 8 can be easily and reliably obtained. In addition, since such a band-shaped separating wall is arranged so as to be able to abut against the peripheral edge or the outer peripheral surface of the electrode plates 7, 8, the electrode plates 7, 8 have moved in a direction intersecting the axis of the sensor 1. In this case, this movement can be limited within a predetermined range, and disconnection of the element-side lead wires 12 can be prevented.

The Pt resistor temperature sensor as described above can be assembled, for example, as shown in FIGS. First, the temperature-sensitive element 2 is inserted into the insertion hole 31 formed in the metal shell 3, and a ring-shaped caulked packing 35 and a cylindrical sleeve 34 are loaded into the insertion hole 31, and then powdered talc (talc) is used. ) Is inserted and pressed (FIG. 6 (a)). Furthermore, the insertion hole 3 on the rear side
1 is loaded with a second sleeve 34, and a second ring 33, which has been temporarily pressed with powdered talc (talc), is inserted again.
Pressing is performed to complete the buffer layer 32 (FIG. 2B). Next, the protection cover 4 is put on the tip 3d of the metal shell 3, and the outer periphery of the overlapped portion is formed by spot welding or the like to form a welded portion W1 and is fixed (FIG. 3C). Buffer layer 3
A cylindrical caulking ring 36 is provided in the insertion hole 31 on the rear side of 2.
Is mounted, and the annular portion at the rear end of the caulking ring 36 and the metal shell 3
The temperature-sensitive element 2 is positioned and held in the axial direction by crimping the rear end annular portion radially inward (FIG. 4D).

While the temperature-sensitive element 2 is inserted through the element insertion hole 51, the front support 5 is placed on the caulking ring 36, and the electrode plates 7, 8 are further disposed thereon. At this time, since the protruding portions 74, 74, 84, 84 of the electrode plates 7, 8 are already bent forward in the axial direction, they are inserted into the concave portions 55 of the front support 5 (see FIG. 5B). The harness-side connecting portions 73 and 83 are not yet bent and the main body portions 71 and 81 are not yet bent.
And is located almost horizontally. Then, the element-side lead wires 12 extending from the rear end of the temperature-sensitive element 2 are respectively welded to the element-side connecting portions 72 and 82 of the electrode plates 7 and 8 by spot welding or the like to form a welded portion W2. (FIG. 6E).

By the way, before the element-side lead wires 12 are joined, the element-side connection portions 72, 82 (body portions 71, 81) of the electrode plates 7, 8 move (displace) in the radial or circumferential direction. If this occurs, there is a possibility that bonding failure or bonding failure may occur. After bonding, the element side connection portions 72, 82 of the electrode plates 7, 8 may be formed.
If the (main body portions 71, 81) are displaced, the element-side lead wires 12, 12 may be disconnected. In the present embodiment, the electrode plates 7, 8 are joined when the element-side lead wires 12, 12 are joined.
Of the electrode plates 7, 8 on the rear end face of the flange portion 53 of the front support 5 by inserting the protrusions 74, 74, 84, 84 of the front support 5 into the recesses 55 of the front support 5.
2, 82 (main body parts 71, 81) are restricted in displacement,
As a result, these problems are less likely to occur, and the yield at the time of joining is improved.

Further, the front support 5 is fixed to the caulking ring 36.
When the electrode plates 7 and 8 are further placed thereon, the rear end edge of the temperature-sensitive element 2 is
1 and 81 (that is, the rear end surface of the flange portion 53 of the front support 5; see FIG. 5B). The position of the rear edge of the temperature sensing element 2 is
Can be set near the joining position of the element-side lead wires 12, 12 on the element-side connection portions 72, 82 (main body portions 71, 81), so that workability such as welding to the element-side lead wires 12, 12 is good. In addition, the length of the element-side lead wires 12 protruding from the rear end of the temperature-sensitive element 2 can be shortened, so that accidents such as short-circuit and disconnection of the element-side lead wires 12 during welding work or the like can be prevented.

Further, since the rear end edge of the temperature sensing element 2 protrudes rearward from the rear end surface of the flange portion 53 of the front support member 5, the rear end surface of the flange portion 53 of the front support member 5 has The rear end protruding portion of the heating element 2 and the bulging portions 54, 54 connected to both sides of the rear end protruding portion form a strip-shaped isolation wall in a form continuous in a predetermined radial direction. The rear end surface of the flange portion 53 is narrowed by the strip-shaped separating wall because it is separated and separated into a portion where the + side electrode plate 7 is placed and a portion where the − side electrode plate 8 is placed. Even when welding work or the like in a space is required, a short circuit or the like hardly occurs.

In any case, the element-side lead wires 12, 1
2 is fixed to the electrode plates 7, 8, so that the element-side lead wires 12, 1 are connected in a later step of connecting the harness-side lead wires 13, 13 to the electrode plates 7, 8.
There is almost no danger of disconnection due to pulling of the cable 2 (see FIG. 5).
(A)).

Next, the harness-side connection portions 73 and 83 of the electrode plates 7 and 8 are bent so as to raise the harness-side connection portions 73 and 83 by approximately 90 degrees toward the rear side in the axial direction, and the harness-side connection portions 73 and 83 are connected to the harness side of the rear support 6. The rear support 6 is placed on the front support 5 and the electrode plates 7 and 8 while being inserted through the partial insertion holes 61 and 61. Further, the front end of the first outer cylinder 10 is put on the rear end of the metal shell 3, and the outer periphery of the overlapped portion is formed by spot welding or laser welding to form a welded portion W3 and joined. On the other hand, the rear end of the first outer cylinder 10 is caulked radially inward via a ring-shaped caulking packing 9, and the rear support 6 (further, the electrode plates 7, 8 and the front support 5) are axially moved. (FIG. 6 (f)).

Now, the harness side connection portions 73, 83 of the electrode plates 7, 8 extending from the first outer cylinder 10 to the rear side in the axial direction through the harness side connection portion insertion holes 61, 61 of the rear support member 6.
One end of each of the harness-side lead wires 13, 13 is connected and fixed via joint terminals 14, 14, respectively (FIG. 7 (g)). As described above, in this step, the element-side lead wires 12, 12 are hardly pulled and disconnected (see FIG. 5A). Subsequently, the harness-side lead wires 13, 13 and the joint terminals 14, 14 are inserted into the separator-side insertion holes 151, 151 of the separator 15.
The separator 15 is placed on the rear edge of the first outer cylinder 10 while being accommodated. Furthermore, the lead wire 1 on the harness side
While inserting the grommet 16 and the grommet 16 into the harness side lead wire insertion holes 161, 161 of the grommet 16,
Is placed on the separator 15 (FIG. 7 (h)). Then, the front end of the second outer cylinder 11 is put on the rear portion of the flange 3c of the metal shell 3, and the outer periphery of the overlapped portion is formed by laser welding or the like to form a welded portion W4 and joined. Finally, the rear end portion of the second outer cylinder 11 is caulked radially inward together with the grommet 16 to complete the Pt resistor temperature sensor 1 in which the airtightness of the opening 111 of the second outer cylinder 11 is maintained. Figure (i).

In the above embodiment, the first outer cylinder 1
One of the outer cylinder 11 and the second outer cylinder 11 may be omitted, and a single outer cylinder may be used. Further, the connection structure according to the present invention may be housed in a cylindrical portion other than the first and second outer tubes 10 and 11.

Hereinafter, the operation of the Pt resistor temperature sensor 1 and the operation of the connection structure will be described. That is, the Pt resistor temperature sensor 1 is fixed to the exhaust pipe or the like of the vehicle at the screw portion 3a of the metal shell 3 as described above, and the harness side lead wires 13, 13 are connected to the controller via a connector plug (not shown). Connected to and used. When the detection unit D of the temperature sensing element 2 is exposed to the exhaust gas, the electric resistance of the Pt resistance temperature detector changes according to the temperature of the exhaust gas.
This resistance change is applied to the element-side lead wires 12, 12, the electrode plate 7,
8. The sensor output is taken out via the harness side lead wires 13, 13 and the like, and the temperature is measured by a temperature measuring bridge circuit or the like.

8 to 10 show modified examples of the lead wire connection structure. FIG. 8 shows a modification of the electrode plate of FIG. 2, in which the plane inclination angles of the projections 74, 74, 84, 84 are 45.
°, the plane inclination angle of the harness side connection portions 73 and 83 is 90 °
Are set respectively. In particular, the harness side connection portion 7
Since the plane inclination angle of 3,83 is set to 90 °,
Compared to the case of 60 °, the harness-side connecting portions 73 and 83 are held while holding a bow-shaped straight portion (a portion corresponding to a bow chord).
(See FIG. 6 (f)). However, in this case, the recess 55 of the front support 5
Also, the plane inclination angles of the harness side connection portion insertion holes 61 of the rear support 6 need to be set to 45 ° and 90 °, respectively (see FIGS. 3A and 4A). Note that the same reference numerals are given to portions common to the embodiment of FIG.

Next, FIG. 9 shows a modification of the connection form of FIG. In the modification of FIG. 9A, the element-side connection portions 72 and 82
Instead of the embodiment shown in FIG. 5A in which the element-side connecting portions 72 and 82 constitute a part of the main body portions 71 and 81,
An example configured separately from 81 is shown. In particular,
Two substantially parallel linear cuts are formed radially inward from the edges of the straight portions of the main body portions 71 and 81, and the claw portions formed inside the cuts are substantially 90 degrees apart from the main body portions 71 and 81. ° bend in a state to raise the element side connection part 7
2, 82 are formed. In this case, similarly to FIG. 5A, it is difficult for the external force applied to the harness-side leads 13, 13 to be directly transmitted to the element-side leads 12, 12. Disconnection is less likely to occur. Note that the harness-side connection portions 73 and 83 are
1, 81 may be configured.

In the modified example of FIG. 9B, the harness-side connection portions 73 and 83 of the electrode plates 7 and 8 are shared with the element-side connection portions 72 and 82 of FIG. 13
Are extended and connected to the main body portions 71, 81 (harness-side connection portions 73, 83) of the electrode plates 7, 8 to be connected and fixed. That is, on the body portions 71, 81 (harness side connection portions 73, 83) of the electrode plates 7, 8, the ends of the element side lead wires 12, 12 and the harness side lead wires 13, 13 are connected.
The element-side lead wires 12 and 12 and the harness-side lead wires 13 and 13 are overlapped (or butted) with their polarities corresponding to each other by spot welding or the like.
And the three main bodies 71, 81 (element-side connection parts 72, 82 or harness-side connection parts 73, 83) are joined and fixed at one time. In the present invention, even in such a case, the element-side lead wires 12 and 12 and the harness-side lead wires 13 and 13 are used.
Are indirectly connected via the electrode plates 7 and 8. That is, even in such a case, the electrode plates 7, 8
Since the main body portions 71, 81 are interposed, the external force applied to the harness-side leads 13, 13 is difficult to be directly transmitted to the element-side leads 12, 12, and the element-side leads 12, 12 are disconnected. This is because it is considered that an effect of reducing the possibility of occurrence occurs. The element-side lead wires 12, 12
Any one of the lead wires 13 and 13 may be overlapped with the other facing downward, or they may be arranged in abutting manner on the main body portions 71 and 81. Of course, the element side lead wires 12, 12
And the harness-side lead wires 13, 13 are connected to the main body portions 71, 8.
It is also possible to bond and fix to the main body portions 71 and 81 separately at arbitrary positions on the first. Note that parts common to the embodiment of FIG. 5 are denoted by the same reference numerals, and description thereof is omitted.

Next, FIG. 10 shows a modification of the front support shown in FIG. In this embodiment, the flange 5 of the front support 5
A peripheral wall portion 54 '(engaging portion) is provided on the peripheral edge of the rear end surface of the third member 3 so as to be continuous with the bulging portion 54 (engaging portion). As a result, the electrode plates 7 and 8 are placed in a space surrounded by the bulging portion 54 and the peripheral wall portion 54 ′ on the rear end face of the flange portion 53 of the front support 5. Therefore, the swelling portion 54 functions to hold the + side electrode plate 7 and the − side electrode plate 8 placed on the rear end face of the flange portion 53 at a predetermined position while ensuring an electrical insulation state between them. There is an advantage that the peripheral wall portion 54 'can ensure the electrical insulation state between the electrode plates 7, 8 and the first outer cylinder 10 more reliably. In addition, the bulging portion 54 and the peripheral wall portion 54 'are both erected in a wall shape in the axial direction of the sensor 1, and are disposed so as to be able to abut against the peripheral edges or the outer peripheral surfaces of the electrode plates 7, 8. The movement of the electrode plates 7 and 8 in the direction intersecting with the axial direction of the sensor 1 is restricted. Note that the outer shapes of the main bodies 71 and 81 of the electrode plates 7 and 8 and the
4 and the shape of the space surrounded by the peripheral wall portion 54 'are substantially matched, the concave portion 55 of the front support 5 and the electrode plate 7,
It is not necessary to provide the 8 projections 74 and 84. However,
In FIG. 10, the device-side lead wires 12, 12 and the electrode plates 7, 8
The concave portion 55 (and the protruding portions 73 and 83) are provided in order to minimize the positional deviation of the main body portions 71 and 81 when the main body portions 71 and 81 are joined to each other. (FIG. 6 (e)
reference). Note that the same reference numerals are given to portions common to the embodiment of FIG.

In the present invention, the resistor constituting the temperature sensing element is a simple substance such as Ni, Rh, W, or an alloy containing these metals in addition to Pt, or a cermet of these metals and ceramic. Is also good. Further, a thermistor made of a metal oxide may be used. Further, the present invention can be applied to other sensors such as a gas sensor (for example, an oxygen sensor) having a detection element inside the cylindrical portion. In these cases, the cross-sectional shape of the detection element is not limited to a square shape.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a Pt resistor temperature sensor as an application example of a lead wire connection structure according to the present invention.

FIG. 2 is a plan view, a side view, and a rear view showing the structure of the electrode plate in FIG. 1, and a plan view and a side view showing an unfolded state.

FIG. 3 is a plan view showing the structure of a front support in FIG. 1;
Front half sectional view, side half sectional view, and bottom view.

FIG. 4 is a plan view showing the structure of the rear support in FIG. 1;
Front half sectional view, side half sectional view, and bottom view.

FIG. 5 is a perspective view showing a connection form between an element side lead wire and a harness side lead wire with respect to an electrode plate, and a front half sectional view showing an assembly structure around the electrode plate.

FIG. 6 is an explanatory diagram of an assembling process of the Pt resistor temperature sensor of FIG. 1;

FIG. 7 is an explanatory view of the assembling process following FIG. 6;

FIG. 8 is a plan view, a side view, and a rear view showing a structure of a modified example of the electrode plate of FIG. 2, and a plan view and a side view showing a developed state.

FIG. 9 is a perspective view showing a modification of the connection configuration of FIG. 5;

FIG. 10 is a plan view, a front half sectional view, a side half sectional view, and a bottom view showing a modified example of the front support of FIG. 3;

[Explanation of symbols]

 Reference Signs List 1 Pt resistor temperature sensor (sensor) 2 Temperature sensing element (detection element) 5 Front support (support member) 54 Swelling part (engaging part) 54 'Peripheral wall part (engaging part) 55 Depression (engaging part) Reference Signs List 6 rear support (supporting member) 7 + side electrode plate (relay portion) 71 main body portion 72 element side connection portion 73 harness side connection portion 74 projecting portion (engagement portion) 8-side electrode plate (relay portion) 81 main body portion 82 Element side connection part 83 Harness side connection part 84 Projection part (engagement part) 10 First outer cylinder (cylindrical part) 11 Second outer cylinder (cylindrical part) 12 Element side lead wire 13 Harness side lead wire

Claims (14)

[Claims] 1. A detection element is arranged inside a cylindrical portion having an opening at at least one end, and an element-side lead wire extending from the detection element and extending outside the cylindrical portion through the opening. The harness side lead wire is held inside the cylindrical portion in a form in which movement of the cylindrical portion in the axial direction is restricted, and is held in an electrically insulated state with respect to the cylindrical portion. A lead wire connection structure for a sensor, wherein the lead wire connection structure is connected via a conductive relay portion. 2. The sensor lead according to claim 1, wherein the relay portion is held in an electrically insulated state by the cylindrical portion by an insulating support member disposed inside the cylindrical portion. Wire connection structure. 3. The lead wire connection structure for a sensor according to claim 2, wherein the support member holds the relay portion so as to sandwich the relay portion from both sides in the axial direction of the cylindrical portion. 4. The sensor lead wire connection structure according to claim 3, wherein the support member is divided into at least two or more parts so as to sandwich the relay portion from both sides in the axial direction of the cylindrical portion. 5. The sensor lead according to claim 2, wherein the support member has an engagement portion that restricts movement of the relay portion in a direction intersecting with an axis of the cylindrical portion. Connection structure. 6. The engaging portion of the supporting member is a concave portion or a protruding portion formed in the supporting member, while the relay portion has a relay portion side protruding portion corresponding to the engaging portion. 6. The lead wire connecting structure for a sensor according to claim 5, wherein a relay-side concave portion is formed. 7. The engagement portion of the support member is provided upright in the support member in a wall shape in the axial direction of the tubular portion, and can be in contact with a peripheral edge or an outer peripheral surface of the relay portion. The lead wire connection structure for a sensor according to claim 5, wherein 8. The relay section includes a main body that is held in an electrically insulated state with respect to the tubular section, and an element-side connection section provided on the main body and connected to the element-side lead wire. And a harness-side connection portion also provided on the main body portion and connected to the harness-side lead wire.
8. The lead wire connection structure for a sensor according to any one of claims 7 to 7. 9. The relay section has a plate-shaped main body section arranged in a direction intersecting with the axis of the cylindrical section, and the support member is connected to the cylindrical section so as to sandwich both end surfaces of the main body section. And an element-side connection portion provided on the main body and connected to the element-side lead wire, and a harness-side connection also provided on the main body portion and connected to the harness-side lead wire The lead wire connection structure for a sensor according to any one of claims 2 to 7, further comprising a portion. 10. The element-side connection portion of the relay section is divided according to the number of the element-side lead wires, and the support member keeps the element-side connection portions electrically insulated from each other. A lead wire connection structure for a sensor according to claim 8. 11. The element-side connection portion of the relay section, which is divided according to the number of the element-side lead wires, is spaced apart from each other so as to separate the detection element. Sensor lead wire connection structure. 12. At least one of the element-side connection portion and the harness-side connection portion of the relay portion is formed integrally with the main body portion or in a form constituting a part of the main body portion. A lead wire connection structure for a sensor according to any one of claims 8 to 11. 13. The element-side lead wire extends from the rear end of the detection element, with the side facing the opening in the axial direction of the cylindrical portion as the rear side, and the relay corresponding to the rear end. 13. The harness-side lead wire is connected to the harness-side connection portion of the relay portion, which is provided on the rear side from the main body portion of the relay portion, while the element-side connection portion is provided. 4. The lead wire connection structure of the sensor according to 1. 14. The sensor lead wire connection structure according to claim 1, wherein the detection element is a plate-shaped temperature sensing element using a metal resistor.