JP2002168825A - Terminal connection structure for sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a terminal connection structure for a sensor in which the defect of the electrical connection of a lead frame to electrode terminal parts of a detecting element is hard to generate in the terminal connection structure for the sensor in a shape in which the lead frame is electrically connected to the electrode terminal parts of the detecting element. SOLUTION: As shown in Fig. (a), the lead frame 10 which is provided at an oxygen sensor 2 is formed so as to be provided with frame bodies 12, bent parts 14 which are formed by bending ends on one side of the frame bodies 12, wavy parts 16 which are formed on the side of the bent parts 14 at the frame bodies 12 and flat plate members 18 which come into contact with the electrode terminal parts of the detecting element. Since the members 18 come into face contact with the electrode terminal parts 30, 32, 34, 36 of the detecting element 4, the contact area of the lead frame 10 with the electrode terminal parts is increased, their contact resistance can be suppressed to be low, and the electrode terminal parts are hard to shave off even when the lead frame 10 is repeatedly swollen and contracted due to a temperature change.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal of a sensor using various plate-shaped detecting elements extending in the axial direction, such as a gas detecting element (gas sensor element) of a gas sensor and a temperature sensing element of a temperature sensor. Regarding the connection structure.

[0002]

2. Description of the Related Art Conventionally, a detection element (a gas sensor element, a temperature-sensitive element, or the like) having a plate-like shape extending in the axial direction and having a detection portion formed at a tip end directed toward a gas to be measured has been assembled. Sensors such as a gas sensor and a temperature sensor are known. In addition, as a gas sensor,
Examples include a λ sensor, a full range air-fuel ratio sensor, an oxygen sensor, and a NOx sensor.

Here, as an example of this type of sensor, a detection element (gas sensor element) for detecting an oxygen concentration in a gas (exhaust gas) to be measured is assembled, and an oxygen sensor attached to an exhaust pipe of an internal combustion engine is mounted. The sensor is shown in FIG.
The oxygen sensor 100 shown in FIG. 5 has a substantially cylindrical metal shell 102 having a screw portion 102a formed on an outer surface thereof for fixing to an exhaust pipe, and is inserted into a cylinder of the metal shell 102, and has a distal end side (see FIG. 5). The middle and lower parts are directed to the gas to be measured, and an oxygen concentration cell element made of an oxygen ion conductive solid electrolyte body and having a detection unit 104a formed thereon and a ceramic heater for the purpose of early activation of the detection unit 104a are laminated. And a plate-shaped detection element 104 extending in the axial direction, and a metal shell 1 for holding the detection element 104.
02, a ceramic holder 106, a talc powder 108, and a ceramic sleeve 110, which are laminated in this order from the inside of the cylinder.
And

Among them, the ceramic holder 106 and the ceramic sleeve 110 have a substantially cylindrical appearance, and an insertion hole is formed along the central axis of the detecting element 104 along a cross section orthogonal to the axial direction. The element 104 is held through these insertion holes.

[0005] Further, the ceramic sleeve 110 has a rear end (upper side in the figure) protruding from the main body 110b to form a protruding portion 110a, and the detecting element 104 is further rearward from the rear end of the protruding portion 110a. It is held in a state of protruding. Then, the protrusion 1 of the ceramic sleeve 110
A caulking ring 112 is arranged on the end surface around 10a, and the talc powder 108 is pressure-filled by caulking the rear end of the metal shell 102 to the ceramic sleeve 110 side via the caulking ring 112. As a result, the detection element 104, the ceramic holder 106, and the ceramic sleeve 110 are fixed to the metal shell 102.

On the other hand, the detecting element 104 is composed of an oxygen concentration cell element having a detecting portion 104a formed on the front end side (lower side in the figure) and a ceramic heater, and has a surface (upper side in the drawing) on the rear end side (upper side in the drawing). A plurality of electrode terminal portions 30 for outputting the electromotive force of the oxygen concentration cell generated by the detection portion 104a to the outside and supplying electricity to the ceramic heater are provided on both surfaces).
32, 34, 36 are formed. Each of the electrode terminals 30, 32, 34, and 36 is connected to the lead frame 131.
Is electrically connected to the lead wire 116 via the. Note that the lead frame 131 is crimped and electrically connected to the lead wire 116.

On the outer periphery of the metal shell 102 on the rear end side,
The outer cylinder 118 is fixed by welding or the like, and the lead wire 1
16 is drawn out through the grommet 120 arranged inside the rear end side of the outer cylinder 118. In the oxygen sensor 100, conduction between the detection element 104 and the outside (external circuit) is achieved via the lead wire 116 and the lead frame 131.

Here, an exploded perspective view of a contact member 130 provided inside the oxygen sensor 100 for connecting the detecting element 104 and the lead frame 131 is shown in FIG.
Shown in As shown in FIG. 6, the contact member 130
Lead frame 131, pair of insulating housings 13
2. It comprises a fixing bracket 133, a pressing spring 134 and a caulking ring 135. And the contact member 130 is comprised by the following procedures.

First, as shown in FIG. 6A, lead wires 116, 116 and two crimped lead frames 1
31 and 131 are ceramic insulating housings 132
To place. Then, as shown in FIG. 6B, a pair of insulating housings 132, 132 on which the lead frames 131, 131 are set are inserted between the pair of insulating housings 132, 132.
In a state where the electrode terminals 30, 32, 34 and 36 of 04 are arranged, they are inserted into a fixing bracket 133 to which a pressing spring 134 having a substantially U-shaped cross section is attached. And this fixing bracket 133
The pressing spring 134 is displaced by placing the caulking ring 135 on the torso and caulking the outer periphery of the caulking ring 135. An elastic force is generated by the displacement of the pressing spring 134, and the insulating housing 132 urges the four lead frames 131 to the electrode terminals 30, 32, 34, 36 at a predetermined pressure by the elastic force. , And a contact member 130.

In other words, the crimping of the caulking ring 135 causes the insulating housing 132 to urge the lead frame 131 against the electrode terminals 30, 32, 34, and 36 of the detection element 104, so that the electrode terminals 30 , 32,3
4 and 36 and the lead frame 131 are electrically connected.

[0011]

However, the above-mentioned contact member 130 applies an urging force for bringing each lead frame 131 into contact with the electrode terminals 30, 32, 34, 36 of the detecting element outside the insulating housing 132. Of the lead frame 131 and the detecting element 104 because the structure depends on the caulking 135 and the pressing spring 134.
Electrical connection with the electrode terminal portion may be defective.

That is, individual differences in the surface shape of the detecting element 104, the lead frame 131, the insulating housing 132
Due to such dimensional errors as described above, the urging force of the detection element 104 with respect to the electrode terminal portion of each lead frame 131 becomes uneven, and the lead frame 131 is not sufficiently urged to the electrode terminal portion, resulting in poor contact between the two. There is a fear. Further, in a gas sensor mounted in an exhaust pipe of an internal combustion engine and used in a high temperature environment, the detection element may be warped due to heat, or the lead frame may be deformed due to thermal expansion. Poor contact with the electrode terminal may occur.

FIG. 6 illustrates a detection element having two electrode terminals formed on one side, but a detection element having three or more electrode terminals formed on one side may be used. As the number of electrode terminals formed on one surface increases, a difference in biasing force between lead frames tends to occur, and electrical contact failure between the lead frame and the electrode terminals tends to occur.

Further, in a gas sensor installed in an environment where the temperature changes drastically, the lead frame expands when the ambient temperature becomes high, and the lead frame contracts when the ambient temperature becomes room temperature or low temperature. And since the electrode terminal portion of the detection element is formed to be thin,
If the expansion and contraction of the lead frame are repeated in accordance with the repetition of the temperature change of the installation environment (hereinafter also referred to as thermal cycle), the electrode terminals are scraped off due to the friction generated between the lead frame and the electrode terminals. In some cases, poor contact between the lead frame and the electrode terminal may occur.

The present invention has been made in view of such a problem, and a sensor in which a lead frame disposed between an insulating protective body and a detecting element is electrically connected to an electrode terminal of the detecting element. In the above terminal connection structure, it is an object to provide a sensor terminal connection structure in which a failure in electrical connection between the lead frame and the electrode terminal portion of the detection element hardly occurs.

[0016]

Means for Solving the Problems According to the first aspect of the present invention, there is provided a detection device having a plate-like shape extending in an axial direction, and a detecting portion provided at a tip end directed toward a gas to be measured. Is formed, a detection element having an electrode terminal portion formed on the surface on the rear end side, a cylindrical insulating protection body arranged to surround the periphery of the rear end side of the detection element, a detection element and the insulation protection body And a lead frame electrically connected to the electrode terminal portion of the detection element, and a terminal connection structure of the sensor, wherein the lead frame is disposed at least in the cylinder of the insulating protection body. A flat plate portion that contacts the electrode terminal portion of the detection element, and an elastic portion that is sandwiched between the detection element and the insulating protective body and urges the flat plate portion against the electrode terminal portion by being compressed and deformed. It is characterized by.

That is, in the lead frame provided in the sensor terminal connection structure of the present invention (claim 1), the flat plate portion is in contact with the electrode terminal portion of the detection element, and the shape of the contact portion is not a point or a line. Since it is a surface, the contact area with the electrode terminal part is increased. As described above, by ensuring a large contact area between the lead frame and the electrode terminal portion by making surface contact, the contact resistance generated between the lead frame and the electrode terminal portion can be suppressed low.

Further, since the lead frame is in contact with the electrode terminal portion on the surface, the temperature change (thermal cycle) in the installation environment of the sensor is compared with the case where the lead frame contacts with the point or line.
When the lead frame repeatedly expands and contracts with the repetition of the above, it is unlikely that the electrode terminal portion is scraped off at the contact location. For this reason, even when the lead frame repeatedly expands and contracts due to a thermal cycle, it is possible to maintain the contact with the electrode terminal portion and to suppress the variation in the contact resistance.

Further, in this sensor terminal connection structure, the urging force for urging the lead frame to the electrode terminal portion of the detection element is not generated only by the urging force applied from the insulating protection member, but is generated by the elasticity of the lead frame. It is also generated by the elastic force generated by the compression deformation of the part itself. Even if a dimensional error occurs in the gap between the detection element and the insulating protective body, such a lead frame is individually elastically sandwiched between the detecting element and the insulating protective body and elastically deformed. The flat plate portion can be biased toward the electrode terminal portion of the detection element, and the electrode terminal portion and the flat plate portion can be satisfactorily contacted with each other, so that poor contact between the lead frame and the electrode terminal portion hardly occurs. .

Therefore, according to the sensor terminal connection structure of the present invention (claim 1), the shape of the contact portion between the lead frame and the electrode terminal portion is a plane, so that the expansion and contraction of the lead frame due to a temperature change. Is repeated, it is less likely that the electrode terminal portion is scraped off. This makes it difficult for poor contact between the lead frame and the electrode terminal to occur, so that the electrical connection between the lead frame and the electrode terminal can be reliably maintained. In addition, since the lead frame includes an elastic portion that urges the flat plate portion to the electrode terminal portion, the distance between the lead frame and the insulating protection body in the same detection element is changed due to factors such as dimensional errors. Therefore, even when the respective components are different from each other, the electrical connection between each lead frame and the electrode terminal portion can be reliably maintained.

In the lead frame, various modes can be considered as an elastic portion having an elastic force for urging the flat plate portion to the electrode terminal portion. For example, the elastic portion includes a detecting element and an insulating protective body. It is preferable to have an elastic force in a direction to increase the distance between the flat portion and the insulating protective body, and to form the flat portion so as to urge the flat portion toward the electrode terminal portion. That is, the lead frame is formed such that the elastic portion contacts the insulating protection body and the flat plate portion contacts the electrode terminal of the detection element. When the lead frame is sandwiched between the detection element and the insulating protection body, the elastic part urges the flat plate part against the electrode terminal part of the detection element by the elastic force, so that the lead frame and the electrode are separated. The electrical connection is realized by making contact with the terminal.

In such a lead frame, since the elastic portion and the flat portion are stacked and come into contact with each other, they are electrically connected at the contact portion, and the elastic portion and the flat portion are not necessarily connected. It is not necessary to form them integrally, and the flat plate portion and the elastic portion can be provided as independent members.

However, when the elastic portion and the flat plate portion are provided as independent members, the respective members (the elastic portion and the flat plate portion) are used when assembling the lead frame to the sensor.
However, since it is necessary to position each member by gripping or the like so as not to deviate from an appropriate position, the assembling operation may be complicated.

Therefore, as the lead frame provided in the sensor terminal connection structure of the above (claim 1), the end portion of the elastic portion and the end portion of the flat plate portion of the lead frame are provided. Are preferably connected and integrally formed. In other words, by forming the elastic portion and the flat portion integrally, their relative positions are fixed,
When assembling the lead frame to the sensor, operations such as gripping the elastic portion and the flat plate portion can be omitted.

According to the sensor terminal connection structure of the present invention (claim 2), when assembling the lead frame to the sensor, operations such as gripping the elastic portion and the flat plate portion can be omitted. In addition, the complexity of the operation can be eliminated. Also, the lead frame may be formed integrally with the elastic portion of the lead frame connected to both ends of the flat plate portion.

That is, the elastic portion is not disposed between the flat plate portion and the insulating protective body, but is disposed so that the elastic portion itself directly contacts the main body (body surface) of the detecting element and the insulating protective body. And, it is formed integrally with the flat plate portion at both ends of the flat plate portion. Then, the flat portion is urged to the electrode terminal portion of the detection element by being sandwiched between the detection element and the insulating protection body and the elastic portion being elastically deformed. Thus, the lead frame comes into contact with the electrode terminal portion in a state where the shape of the contact portion becomes a plane, and realizes electrical connection with the electrode terminal portion.

Therefore, according to the sensor terminal connection structure of the present invention (claim 3), the distance between the same detection element and the insulating protection body differs at each position where the lead frame is disposed, or due to a temperature change. Even if the expansion and contraction of the lead frame are repeated, poor contact between the lead frame and the electrode terminal portion is less likely to occur, and the electrical connection between the lead frame and the electrode terminal portion can be reliably maintained.

The elastic portion of the lead frame provided in the terminal connection structure of the sensor described above (any one of claims 1 to 3) may have various shapes. As described above, the elastic portion of the lead frame may be formed in a wavy shape, and may be sandwiched between the detection element and the insulating protection body to be compressed and deformed in the amplitude direction of the wavy shape.

The flat portion is detected by the elastic portion by arranging the lead frame so that the amplitude direction of the wavy shape of the elastic portion (direction of height difference) is in the direction of the gap between the detecting element and the insulating protection body. It urges the electrode terminal of the element. By sandwiching the lead frame having such an elastic portion between the detection element and the insulating protection body, the elastic portion can satisfactorily urge the flat plate portion toward the electrode terminal portion of the detection element, The lead frame and the electrode terminal can be reliably contacted.

Therefore, according to the sensor terminal connection structure of the present invention (claim 4), even when the distance between the same detecting element and the insulating protection body differs at each position where the lead frame is arranged, the lead frame of the lead frame can be used. Poor contact between the flat plate portion and the electrode terminal portion is less likely to occur, and the electrical connection between the lead frame and the electrode terminal portion can be reliably maintained.

Further, as the terminal connection structure of the above-mentioned sensor (any one of claims 1 to 4), as described in claim 5, a cylindrical metal shell surrounds the periphery of the detection element. It is preferable that the insulating protection body is disposed and fixed in the metal shell. That is, the sensor is configured such that the detection element is fixed to the metal shell via the insulating protective body by fixing the insulating protective body in the metal shell.

As described above, by holding the insulating protective body for holding the lead frame between the detection element and the detection element in the metal shell, even when strong vibration occurs at the installation position of the sensor,
The insulating protector is stably held in the metal shell, and it is difficult for the lead frame to separate from the electrode terminal of the detection element.

Further, the internal structure of the sensor can be simplified, and workability in the manufacturing process of the sensor can be improved. Furthermore, by fixing the insulating protection body in the metal shell, members such as a fixing metal and a caulking for holding the insulating protection body that sandwiches the lead frame between the detection element as in the related art are separately and independently provided. Therefore, the number of components constituting the sensor can be reduced, and the cost of the sensor (terminal connection structure of the sensor) can be reduced.

Therefore, according to the sensor terminal connection structure of the present invention (claim 5), the electrical connection between the lead frame and the electrode terminal portion of the detection element can be favorably performed even when the sensor is greatly subjected to vibration. Therefore, the occurrence of poor electrical contact between the lead frame and the electrode terminal portion can be suppressed. Further, since the internal structure of the sensor can be simplified, workability in the manufacturing process of the sensor can be improved, and the number of parts constituting the sensor can be reduced, so that the cost of the sensor can be reduced. Can be achieved.

In the terminal connection structure for the sensor described above (any one of claims 1 to 5), claim 6
As described in above, the detection element may be a gas detection element for detecting a component to be detected in a gas to be measured. In other words, some gas detection elements provided in a gas sensor exhibit characteristics as a detection element when placed in a high-temperature environment, and such a gas detection element has a temperature when the gas sensor is used and when it is not used. Since the difference is large, the expansion and contraction of the lead frame are repeated, so that the electrode terminal portion formed on the gas detection element is easily scraped off.

Therefore, by using the above-described sensor terminal connection structure in such a gas sensor, it is possible to prevent the electrode terminal portions in all the contact portions from being scraped off by the influence of the temperature change, and it is possible to prevent the gas sensor from being connected to the lead frame. Electrical connection with the electrode terminal of the element can be maintained.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sensor having a terminal connection structure according to the present invention will be described below with reference to the drawings. In this embodiment, a description will be given of an oxygen sensor which is a kind of gas sensor, in which a detection element (gas sensor element) for detecting an oxygen concentration in exhaust gas to be measured is assembled and which is mounted on an exhaust pipe of an internal combustion engine. .

FIG. 1 is a sectional view showing the overall structure of the oxygen sensor 2 of the present embodiment. The oxygen sensor 2 is different from the oxygen sensor 100 shown in FIG. 5 in the shape of the detection element, the terminal connection structure between the electrode terminal of the detection element and the lead frame that is electrically connected to the lead wire, and the rear end of the oxygen sensor itself. Side (Fig. 1
Are different from each other, and the other parts are configured in the same manner. Here, portions common to the oxygen sensor 100 shown in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted.

That is, the oxygen sensor 2 is a cylindrical metal shell 1
02, an oxygen concentration cell element which is inserted into the cylinder of the metal shell 102, the tip side (lower side in the figure) is directed to the exhaust gas to be measured, and is formed of an oxygen ion conductive solid electrolyte body and formed with the detection section 4a. And a ceramic heater for the purpose of early activation of the detection unit 4a are laminated, and the detection element 4 has a plate shape extending in the axial direction, and a cylinder of the metal shell 102 for holding the detection element 4. The ceramic holder 106, the talc powder 108, and the ceramic sleeve 6, which will be laminated from the inner front end side, and the electrode terminals 30, 32, 34, 36 formed on the rear end side of the detection element 4 are electrically contacted. A plurality of (four in this embodiment) long lead frames 10 to be described later to be connected are provided.

The detection element 4 has a rectangular axial cross section, and as shown in FIG. 2A, an oxygen concentration cell element 20 formed in a plate shape extending in the axial direction.
The heater 22 for activating the detection unit 4a of the oxygen concentration cell element 20 is formed by lamination. The oxygen concentration cell element 20 is formed of, for example, an oxygen ion conductive solid electrolyte mainly composed of zirconia or the like. The heater 22 is formed of, for example, a known ceramic heater in which a resistance heating element pattern 24 made of conductive ceramic is embedded in a ceramic base such as alumina.

On the tip side (left side in FIG. 2) of the oxygen concentration cell element 20 in the axial direction, porous electrodes 26 and 28 are formed on both sides, and are sandwiched between these electrodes 26 and 28. The solid electrolyte portion constitutes the detection section 4a of the detection element 4. Also, from the porous electrodes 26 and 28,
The rear end side of the oxygen concentration cell element 20 along the axial direction (FIG.
Of the electrode leads 26a, 2 extending to the right
8a are integrally formed. Among them, the end of the electrode lead portion 26 a from the electrode 26 on the side not facing the heater 22 is used as the electrode terminal portion 30. On the other hand, the electrode lead portion 28a of the electrode 28 on the side facing the heater 22
As shown in FIG. 2C, vias 28b crossing the oxygen concentration cell element 20 in the thickness direction are connected to electrode terminal parts 32 formed on the element surface on the opposite side.
Numerals 32 are arranged at intervals at the end of the plate surface of the oxygen concentration cell element 20.

On the other hand, the heater 22 is formed with two lead portions 24a for conducting to the resistance heating element pattern 24, and is opposed to the oxygen concentration cell element 20 of the heater 22, as shown in FIG. Electrode terminal portions 34 and 36 formed at the end of the plate surface on the side not to be connected are connected via vias 38 respectively. Then, as can be seen from the cross-sectional view of the detection unit 4a shown in FIG.
Are bonded to each other via a ceramic (for example, zirconia ceramic or alumina ceramic) layer 40.

The detecting element 4 configured as described above is similar to that shown in FIG.
As shown in the figure, the detection unit 4 on the tip side (the lower side in FIG. 1)
a is fixed in the metal shell 102 in a state protruding from the tip of the metal shell 102 fixed to the exhaust pipe.
The detection element 4 is a conventional oxygen sensor 100 shown in FIG.
Are formed to be shorter in the axial direction than the detection element 104 provided in the device.

On the other hand, a metal double protector 42 having a plurality of holes and covering a protruding portion of the detecting element 4 is provided on the outer periphery of the distal end side (lower side in FIG. 1) of the metal shell 102.
a and 42b are attached by welding or the like. The outer cylinder 44 is fixed to the outer periphery of the rear end side of the metal shell 102 by welding or the like. Further, inside the rear end side (upper side in FIG. 1) of the outer cylinder 44, electrical connection with the respective electrode terminal portions 30, 32, 34, 36 of the detecting element 4 is made to the outside via the lead frame 10. Lead wires 46 for
A grommet 50 and a ceramic separator 48 in which a lead wire insertion hole through which is inserted are formed. Note that the ceramic separator 48 has a flange portion 62 that protrudes outward over the entire circumference on the outer peripheral surface substantially at the center in the axial direction. Outer cylinder side support 6
4 supported. The grommet 50 is elastically fitted inside the opening on the rear end side of the outer cylinder 44.

The detecting element 4 includes a ceramic holder 106, a talc powder 108, and a ceramic sleeve 6 disposed from the front end side of the metal shell 102 in the cylinder, and a lead frame 10 disposed between the ceramic sleeve 6 and the ceramic holder 106. The detection element 4 is fixed in a state in which the periphery of the rear end side of the detection element 4 on which the electrode terminals 30, 32, 34, 36 are formed is covered with the ceramic sleeve 6.

Among them, the ceramic sleeve 6 is a ceramic sleeve 110 provided in the conventional oxygen sensor 100.
This differs from FIG. 5 mainly in the shape of the insertion hole through which the detection element is inserted (held), and the other shapes and structures are the same. That is, the ceramic sleeve 6 is formed as shown in FIG.
As shown in FIG. 4B, which is a bottom view (enlarged bottom view) of the ceramic sleeve 6 viewed in a direction A (that is, a direction from the front end to the rear end) described in FIG. The rear end side (upper side in FIG. 4A) projects from the main body 58 to form a protruding portion 52, and an insertion hole 54 for accommodating the detecting element 4 and the lead frame 10 is formed along the central axis. Have been. And in the insertion hole 54,
Grooves 56 are formed on the inner wall corresponding to the plate surface (front surface) on the rear end side where the electrode terminals 30, 32, 34, and 36 of the detection element 4 are formed. That is, four grooves 56 are formed in the insertion hole 54, whereby the insertion holes 5 are formed.
4 has a substantially “E” -shaped cross section.

Here, the ceramic sleeve 6 corresponds to an “insulating protection body” described in the claims. Also, in FIG. 4A, the right half of the ceramic sleeve 6 is
It is shown as a cross-sectional view corresponding to the BB cross-section in FIG. On the other hand, the lead frame 10 is shown in FIG.
As shown in FIG. 1, the entire appearance is substantially L-shaped. That is, the lead frame 10 includes a frame body 12, a bent portion 14 formed by bending one end of the frame body 12, a corrugated portion 16 formed on the bent portion 14 side of the frame body 12, Straight-shaped flat plate member 18 for contacting the electrode terminal of the element
And The lead frame 10 is made of, for example, a well-known inconel or stainless steel that can maintain elasticity (spring elasticity) even when repeatedly exposed to high temperatures.

The wavy portion 16 is formed in a wavy shape, and the lead frame 10 is disposed between the detecting element 4 and the ceramic sleeve 6 so that the wavy portion 1 is formed.
Numeral 6 is sandwiched between the detecting element 4 and the ceramic sleeve 6 so as to be compressed and deformed (elastically deformed) in the amplitude direction of the wavy shape. Thus, when the lead frame 10 is mounted between the ceramic sleeve 6 and the detecting element 4, the flat member 18 is urged toward the electrode terminal of the detecting element 4 by the elastic deformation of the wavy portion 16. You.

Here, the corrugated portion 16 of the lead frame 10 corresponds to the “elastic portion” described in the claims, and the flat plate member 18 corresponds to the “flat portion” described in the claims.
Is equivalent to Then, as shown in FIG. 3 (b), the lead frame 10, the detecting element 4 and the ceramic sleeve 6 are integrally assembled by inserting the lead frame 10 and the detecting element 4 into the insertion holes 54 of the ceramic sleeve 6. Can be

At this time, in the lead frame 10, a part of the frame body 12, the wavy portion 16 and the flat plate member 18 are arranged in the groove 56 of the insertion hole 54 of the ceramic sleeve 6, and the bent portion 14 3B, the end of the frame body 12 opposite to the bent portion 14 (the upper end in FIG. 3B) protrudes from the ceramic sleeve 6.
Is connected to the lead wire. At this time, the lead frame 10 has a wavy portion 16 formed of the ceramic sleeve 6.
Abuts on the inner wall of the insertion hole 54 (groove 56) and the flat plate member 18, and the flat plate member 18 is
32, 34, and 36 are arranged in contact with each other.

That is, the lead frame 10 and the detecting element 4
And the ceramic sleeve 6 are integrally assembled, so that the electrode terminals 30, 32, 34,
36 come into contact with the corresponding flat plate member 18 of the lead frame 10.

Here, the lead frame 10 and the detecting element 4
And a flat plate member 18 of the lead frame 10 when the ceramic sleeve 6 is integrally assembled.
FIG. 3C is an enlarged view of a portion where the electrode terminal portion 30 of the detection element 4 contacts. In FIG. 3C, the illustration of the ceramic sleeve 6 is omitted.

As shown in FIG. 3C, in the lead frame 10, the flat plate member 18 is in contact with the electrode terminal portion 30 and the wavy portion 16 of the detecting element 4, and the wavy portion 1 is provided.
6 is a pressure (clamping force) from the inner wall of the ceramic sleeve 6 (not shown in FIG. 3C) and the surface of the detection element 4.
In response, the flat member 18 is urged to the electrode terminal 30 by being elastically deformed (compressed) by being sandwiched in the space direction between the detecting element 4 and the ceramic sleeve 6.

As a result, the flat plate member 18 comes into contact with the electrode terminal portion 30 of the detection element 4 and the corrugated portion 16 comes into contact with the flat plate member 18 and the ceramic sleeve 6, so that the lead frame 10 and the electrode terminal portion 30 Are electrically connected. The pair of lead frames 10 arranged on both surfaces of the detection element 4 hold the detection element 4 by the elastic force of the wavy portion 16. In addition,
The elastic force of the corrugated portion 16 is set to a size at which the flat plate member 18 and the electrode terminal portion 30 can come into contact with each other so that the flat plate member 18 and the electrode terminal portion 30 do not separate from each other. The thickness of the flat plate member 18 itself is set to be equal to or less than the thickness of the wavy portion 16 itself, thereby maintaining the electrical connection between the lead frame 10 and the electrode terminal portion 30.

Further, the flat plate member 18 is in contact with not only the electrode terminal portion 30 but also the main body of the detecting element 4. Thus, a large contact area between the flat plate member 18 and the detecting element 4 can be ensured. Thus, the lead frame 10 holds the detection element 4. Thereby, the detection element 4 is fixed to the ceramic sleeve 6.

The ceramic sleeve 6 which holds the lead frame 10 between the detection element 4 and the lead frame 10 in this manner is fixed in the metal shell 102 so that the oxygen sensor 2
It is arranged inside. In the oxygen sensor 2, FIG.
As shown in (1), a lead wire 46 is fixed to an end (upper portion in FIG. 1) of the frame body 12 of the lead frame 10 protruding from the ceramic sleeve 6 by welding or swaging.

As described above, each of the lead frames 10 used in the oxygen sensor 2 of the present embodiment has the flat plate member 18 urged toward the electrode terminal of the detecting element 4 by the corrugated portion 16. 4 electrode terminal portions 30, 32, 3
4, 36, and the shape of the contact portion is not a point or a line but a surface, so that the contact area with the electrode terminal portion is increased. As described above, by ensuring a large contact area between the lead frame 10 and the electrode terminals 30, 32, 34, and 36 by surface contact, a space between the lead frame 10 and the electrode terminals 30, 32, 34, and 36 is secured. The resulting contact resistance can be kept low.

Since the lead frame 10 comes into contact with the electrode terminals 30, 32, 34, and 36 on the surface,
When the lead frame 10 repeatedly expands and contracts due to a temperature change (thermal cycle) of the oxygen sensor 2 as compared with the case where the contact is made by a point or a line, the electrode terminal 3
It is unlikely that 0, 32, 34, 36 will be scraped off. Therefore, even when the lead frame 10 repeatedly expands and contracts due to the heat cycle generated by the presence or absence of heat generated by the heater 22 of the detecting element 4 when the oxygen sensor 2 is used and when the oxygen sensor 2 is not used, the lead terminal 10 can be used. Part 3
0, 32, 34, 36 can be maintained,
In addition, variations in contact resistance can be suppressed.

Further, the flat plate member 18 of the lead frame 10 is applied to the electrode terminals 30, 32, 34, 3 of the detecting element 4 by the urging force applied from the ceramic sleeve 6.
6 as well as being urged by the electrode terminals 30, 32, 34, 36 by the elastic force of the wavy portion 16, and in contact with the electrode terminals 30, 32, 34, 36. In such a lead frame 10, even when a dimensional error occurs in the gap between the detecting element 4 and the ceramic sleeve 6, the corrugated portions 16 individually elastically deform (compressively deform) between the detecting element 4 and the ceramic sleeve 6. ), The plate member 18 is urged and the electrode terminal portions 30, 32, 3
4,36 can be contacted well.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and can take various forms. Then, the second lead frame 10b in which the frame main body 12 and the flat plate portion 18a are connected and integrally formed will be described next with reference to FIGS. 8 (a) and 8 (b). The second lead frame 10b can be provided in place of the lead frame 10 in the oxygen sensor 2 described in the above-described embodiment (hereinafter, referred to as a first embodiment).

FIG. 8 (a) is an external view of the second lead frame 10b, and FIG. 8 (b) shows a case where the second lead frame 10b, the detecting element 4 and the ceramic sleeve 6 are integrally assembled. Second lead frame 10b
5 is an enlarged view of a portion where the wavy portion 16, the flat plate portion 18a, and the electrode terminal portion 34 of the detection element 4 abut.

As shown in FIG. 8A, the second lead frame 10b has a wavy portion 16 in the frame main body 12, and the end of the wavy portion 16 is bent.
A flat plate portion 18a is formed. When the oxygen sensor 2 is formed, the second lead frame 10b is
As shown in (b), the flat plate portion 18a is arranged so as to contact the electrode terminal portion 34 of the detection element 4. That is, the second
In the lead frame 10b, since the flat plate portion 18a is formed integrally with the frame main body 12, the relative position between the flat plate portion 18a and the corrugated portion 16 of the frame main body 12 is fixed.

Therefore, when assembling the second lead frame 10b to the oxygen sensor 2, it is not necessary to fix the positional relationship between the flat plate portion 18a and the frame main body 12, and the flat plate member 18 and the frame main body 12 are separately provided. First formed
Compared to the lead frame 10 of the embodiment, the complexity of assembling the sensor with the oxygen sensor 2 can be eliminated.

Next, as in the case of the second lead frame 10b, the flat plate portion 18a is formed integrally with the frame main body 12, and the third lead frame 10c having the bent portion 14 abutting on the lower end surface of the ceramic sleeve 6. About FIG. 8
This will be described with reference to FIG. 8C and FIG. The third lead frame 10c is provided in the above-described embodiment (hereinafter referred to as the first lead frame 10c).
The oxygen sensor 2 described in the embodiment may be provided instead of the lead frame 10.

FIG. 8 (c) is an external view of the third lead frame 10c, and FIG. 8 (d) shows a case where the third lead frame 10c, the detecting element 4 and the ceramic sleeve 6 are integrally assembled. Of the third lead frame 10c
5 is an enlarged view of a portion where the wavy portion 16, the flat plate portion 18a, and the electrode terminal portion 34 of the detection element 4 abut.

As shown in FIG. 8C, the third lead frame 10c has a flat plate portion 18 like the third lead frame.
a is formed integrally with the wavy portion 16, and a bent portion 14 is provided at a connecting portion between the wavy portion 16 and the flat plate portion 18 a. When forming the oxygen sensor 2, the third lead frame 10 c is arranged so that the flat plate portion 18 a contacts the electrode terminal portion 34 of the detection element 4, as shown in FIG. The bent portion 14 is in contact with the front end surface of the ceramic sleeve 6.

As described above, since the third lead frame 10c has the bent portion 14, the position of the flat plate portion 18a inside the insertion hole 54 of the ceramic sleeve 6 can be easily determined, and the flat plate portion 18a and the detecting element can be easily detected. 4 can be surely brought into contact with the electrode terminal portion 34.

Next, a fourth lead frame 10d in which a flat plate portion 18a is formed between the first elastic connecting portion 16c and the second elastic connecting portion 16d will be described with reference to FIGS.
This will be described with reference to FIG. The fourth lead frame 10d can be provided in place of the lead frame 10 in the oxygen sensor 2 described in the above-described embodiment (hereinafter, referred to as a first embodiment).

FIG. 8 (e) is an external view of the fourth lead frame 10d, and FIG. 8 (f) shows a case where the fourth lead frame 10d, the detecting element 4 and the ceramic sleeve 6 are integrally assembled. Of the fourth lead frame 10d
3 is an enlarged view of a portion where the wavy portion 16, the flat plate portion 18a, and the electrode terminal portion 34 of the detection element 4 abut.

That is, in the fourth lead frame 10d, the first elastic connecting portion 16c and the second elastic connecting portion 16d
Are arranged not directly between the flat plate portion 18a and the ceramic sleeve 6 but directly in contact with the detection element 4 and the ceramic sleeve 6, and
a at both ends. When forming the oxygen sensor 2 using the fourth lead frame 10d,
As shown in FIG. 8 (f), the first elastic connecting portion 16c and the second
When the elastic connecting portion 16d is elastically deformed, the flat plate portion 18 is formed.
a is urged to the electrode terminal portion 34 of the detection element 4. Thus, the fourth lead frame 10d contacts the electrode terminal portion 34 of the detection element 4 in a state where the shape of the contact portion is a plane, and realizes electrical connection.

In the fourth lead frame 10d, the first elastic connecting portion 16c comes into contact with the electrode terminal portion 34,
The second elastic connecting portions 16d are in contact with the surface of the detecting element 4 (portions other than the electrode terminal portions) and are elastically deformed (compressed). For this reason, by making the elastic force of the second elastic connecting portion 16d larger than the elastic force of the first elastic connecting portion 16c, the detection element 4 can be more firmly held. The first elastic connecting portion 16c and the second elastic connecting portion 16d of the fourth lead frame 10d correspond to an "elastic portion" according to the third aspect of the present invention.

Also, the number of electrode terminals of the detecting element is not limited to four, and the number of electrode terminals 230, 232, 234, 236 and 23 shown in FIG.
The sensor terminal connection structure of the present invention can also be applied to a case where a signal path of an electric signal to be output is formed in the detection element 5 including 8, 240.

FIG. 7B is an external view of the detection element 5 when viewed from the rear end side (the direction of arrow D in FIG. 7A). As shown in FIG. 4C, the ceramic sleeve 6 for disposing the detection element 5 having six electrode terminals has six grooves 56 formed inside the insertion hole 54.

The sensor terminal connection structure of the present invention can be applied to a detecting element in which the number of electrode terminal portions formed differs between one surface and the other surface. For example, as shown in FIG. 7C, three electrode terminal portions 230, 232, and 234 are formed on one surface, and two electrode terminal portions 236 and 238 are formed on the other surface. The detection element 7. When applied to the detecting element 7, the total size of the widths of the lead frames corresponding to the electrode terminals 230, 232, and 234 on the upper surface and the lead frame corresponding to the electrode terminals 236 and 238 on the lower surface. It is preferable that the total size of each width is equal. This makes it possible to balance the urging forces with respect to the upper surface and the lower surface of the detection element 7, avoid applying an excessive urging force to some of the electrode terminal portions, and remove the electrode terminal portions. Can be prevented.

Furthermore, the terminal connection structure of the sensor of the present invention can be applied to the sensor having the conventional structure shown in FIG. 5, and when a detection element having a large number of electrode terminals is provided, the electrode terminal structure is used. The variation in the urging force can be suppressed, and the electrical connection between the lead frame and the electrode terminal can be maintained. In addition, in the sensor shown in FIG. 5, the insulating housing 132 corresponds to an insulating protective body in the claims.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an overall configuration of an oxygen sensor according to an embodiment.

FIG. 2 is an explanatory diagram of a detection element.

FIG. 3A is an external view of a lead frame,
(B) is a lead frame assembled integrally,
It is sectional drawing which shows a detection element and a ceramic sleeve, (c) is an enlarged view of the part which the flat part of a lead frame and the electrode terminal part of a detection element contact.

FIG. 4 is an explanatory diagram of a ceramic sleeve.

FIG. 5 is a cross-sectional view showing the overall configuration of a conventional oxygen sensor.

FIG. 6 is an exploded perspective view of a contact member provided inside a conventional oxygen sensor.

FIGS. 7A and 7B are explanatory views of a detecting element provided with six electrode terminals, and FIG. 7C is an explanatory view of a detecting element provided with five electrode terminals.

FIGS. 8A, 8C, and 8E are external views of a second lead frame, a third lead frame, and a fourth lead frame, respectively. FIGS. FIG. 6 is an enlarged view of a portion where a flat plate portion of a lead frame, a third lead frame, a fourth lead frame and an electrode terminal portion of a detection element are in contact.

[Explanation of symbols]

2 ... oxygen sensor, 4,5,7 ... detector, 4a ... detector, 6 ... ceramic sleeve, 10 ... lead frame,
10b: second lead frame, 10c: third lead frame, 10d: fourth lead frame, 12: frame body, 14: bent portion, 16: wavy portion, 16c: first elastic connecting portion, 16d: second elastic Connection part, 18 ... flat plate member, 1
8a: flat plate portion, 30, 32, 34, 36 ... electrode terminal portion.

Claims (6)

[Claims] A detection element having a plate-like shape extending in the axial direction, a detection unit formed on a front end side facing a gas to be measured, and an electrode terminal formed on a surface on a rear end side; A cylindrical insulating protective body arranged to surround the periphery of the rear end side of the detecting element; disposed between the detecting element and the insulating protective body, and electrically connected to an electrode terminal of the detecting element. A lead frame, wherein the lead frame is disposed at least in a cylinder of the insulating protection body and is in contact with an electrode terminal of the detection element; An elastic portion that is sandwiched between an element and the insulating protection body and compressively deforms to urge the flat plate portion against the electrode terminal portion. 2. The sensor terminal connection structure according to claim 1, wherein, in the lead frame, the elastic portion and the flat plate portion are connected and integrally formed. 3. The sensor terminal according to claim 1, wherein the elastic portion of the lead frame is connected to both ends of the flat plate portion to be integrally formed. Connection structure. 4. The lead frame, wherein the elastic portion is formed in a wavy shape, and is sandwiched between the detection element and the insulating protection body, and is compressed and deformed in the amplitude direction of the wavy shape. The terminal connection structure for a sensor according to any one of claims 1 to 3, wherein: 5. The metal shell according to claim 1, wherein a cylindrical metal shell is arranged so as to surround the periphery of the detection element, and the insulating protection body is fixed in the metal shell. A terminal connection structure for the sensor according to any one of the above. 6. The sensor according to claim 1, wherein the detection element is a gas detection element for detecting a component to be detected in a gas to be measured. Terminal connection structure.