JP2016121979A - Sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor which hardly has a disconnection between a signal path part and a resistance part in an installation environment in which temperature change occurs.SOLUTION: A case 61 of a non-resonance type knocking sensor 1 covers a joint part 27a between a lower surface-side electrode member 17a and a resistance element 27 and a joint part 27b between an upper surface-side electrode member 19a and the resistance element 27, and is made of 66 nylon containing 45 mass% of glass fiber. Namely, the case 61 is made of a material which contains the glass fiber and a coefficient of thermal expansion of 2×10[/°C] or less in a flow direction. The knocking sensor 1 comprising such a case 61 can suppress a size variation amount of the case 61 even if temperature change occurs in an installation environment of the sensor, and has the joint part 27a and joint part 27b suppressed from being disconnected (broken) owing to size change of the case 61.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sensor that generates a sensor signal that changes in accordance with a change in state of a measurement target.

  As a sensor that generates a sensor signal that changes in response to a change in the state of a measurement target, a signal generation unit that generates a sensor signal that changes in response to a change in the state of the measurement target, and a signal path unit that forms a transmission path for the sensor signal A sensor having a configuration including a resistance portion connected to the signal path portion and a resin molding portion that is molded with resin and covers at least the connection portion between the signal path portion and the resistance portion is known.

Specific examples of the sensor having such a configuration include a knocking sensor that detects knocking occurring in an internal combustion engine (Patent Documents 1 and 2).
This knocking sensor generates a sensor signal (knocking detection signal) that changes according to the state of occurrence of knocking in the internal combustion engine. The knocking detection signal can be used, for example, to determine the presence or absence of knocking in a knocking determination device.

  The resistance unit functions as an abnormality detection resistor for detecting disconnection (breakage) of the electrical path between the resistance unit and an external engine control device connected to the sensor.

JP-A-2005-249601 JP 2006-300605 A

However, in the above sensor, the connection portion between the signal path portion and the resistance portion may be broken (broken) due to a temperature change in the installation environment of the sensor.
That is, when the dimensional change of the resin molded portion occurs due to a temperature change, stress is generated in the connection portion between the signal path portion and the resistance portion, and the connection portion between the signal path portion and the resistance portion is disconnected (breaks). )there is a possibility.

And when such a disconnection (break) arises, a resistance part will not function normally.
Therefore, an object of the present invention is to provide a sensor in which disconnection (breakage) between a signal path portion and a resistance portion is unlikely to occur even in an installation environment in which a temperature change occurs.

The sensor according to the first aspect of the present invention includes a signal generation unit, a signal path unit, a resistance unit, and a resin molding unit.
The signal generator generates a sensor signal that changes according to a change in the state of the measurement target. The signal path section forms a sensor signal transmission path. The resistance unit is connected to the signal path unit.

The resin molding part is molded of resin and covers at least the connection part between the signal path part and the resistance part. Moreover, the resin molding part contains glass fiber, and is formed with the material whose linear expansion coefficient of a flow direction is 2 * 10 < ^-5 > [/ degreeC] or less.

In a resin molded part formed of a material having a linear expansion coefficient in the flow direction of 2 × 10 ⁻⁵ [/ ° C.] or less, the amount of dimensional change when a temperature change occurs is limited within a certain range.
For this reason, even if the temperature change in the installation environment of the sensor occurs, the dimensional change amount of the resin molded portion can be suppressed, and the connection portion between the signal path portion and the resistance portion is disconnected (broken) by the dimensional change of the resin molded portion. This can be suppressed.

Therefore, according to this sensor, even in an installation environment where a temperature change occurs, it is difficult for the signal path portion and the resistance portion to be disconnected (broken).
A sensor according to another aspect of the present invention includes a signal generation unit, a signal path unit, a resistance unit, and a resin molding unit.

The signal generator generates a sensor signal that changes according to a change in the state of the measurement target. The signal path section forms a sensor signal transmission path. The resistance unit is connected to the signal path unit.
The resin molding part is molded of resin and covers at least the connection part between the signal path part and the resistance part. In addition, the resin molded part contains glass fibers, the linear expansion coefficient in the flow direction is 2 × 10 ⁻⁵ [/ ° C.] or less, and a perpendicular line that is perpendicular to the flow direction. It is formed of a material having an expansion coefficient of 7 × 10 ⁻⁵ [/ ° C.] or less.

A resin molded part formed of a material having a linear expansion coefficient in the flow direction of 2 × 10 ⁻⁵ [/ ° C.] or less and a linear expansion coefficient in the perpendicular direction of 7 × 10 ⁻⁵ [/ ° C.] or less, The amount of dimensional change when a temperature change occurs is limited within a certain range.

  For this reason, even if the temperature change in the installation environment of the sensor occurs, the dimensional change amount of the resin molded portion can be suppressed, and the connection portion between the signal path portion and the resistance portion is disconnected (broken) by the dimensional change of the resin molded portion. This can be suppressed.

Therefore, according to this sensor, even in an installation environment where a temperature change occurs, it is difficult for the signal path portion and the resistance portion to be disconnected (broken).
In addition, as a resistance part, what functions as an abnormality detection resistance for detecting the disconnection (break) of the electrical path between the said resistance part and the external engine control apparatus connected to a sensor, and a resistance part The thing which functions as an abnormality detection resistance for detecting the short circuit between signal generation parts can be mentioned.

  In addition, the “linear expansion coefficient in the flow direction” refers to a sample (test piece) in the flow direction in which the resin is injected from the gate into the mold during the injection molding of the resin containing glass fibers. It means the measured linear expansion coefficient (linear expansion coefficient). The term “linear expansion coefficient in the right-angle direction” means a linear expansion coefficient (linear expansion coefficient) measured using a sample (test piece) in a direction perpendicular to the flow direction.

Next, in the above-described sensor, the resin molding unit may cover the signal generation unit, the signal path unit, and the resistance unit.
That is, the sensor is not limited to a configuration in which the resin molding part covers only the signal path part and the resistance part, and the signal generation part is provided outside the resin molding part. The structure which covers a part and a resistance part may be sufficient.

Such a sensor has a configuration in which a signal generation unit, a signal path unit, and a resistance unit are integrally provided inside the resin molding unit, and the installation locations of the sensors can be integrated into one location.
Next, in the above-described sensor, the signal generation unit may be a piezoelectric element, and the measurement target may be knocking of the internal combustion engine.

  In other words, the knocking sensor that detects knocking of the internal combustion engine is likely to cause a temperature change at the location where the sensor is installed. However, by applying the present invention to the knocking sensor, disconnection (breakage) between the signal path portion and the resistance portion is caused. It is difficult to produce.

  According to the sensor of the present invention, disconnection (breakage) between the signal path portion and the resistance portion is unlikely to occur even in an installation environment in which a temperature change occurs.

It is a front view showing the external appearance of a non-resonant type knocking sensor. It is sectional drawing which shows the internal structure of a knocking sensor. It is explanatory drawing which showed typically the positional relationship of a resistive element, a lower surface side electrode member, and an upper surface side electrode member. It is a disassembled perspective view of a part of component provided in the inside of a knocking sensor. It is explanatory drawing which shows the measurement result which measured the correlation of the glass content rate and linear expansion coefficient in 66 nylon (PA66). It is sectional drawing which shows the internal storage structure of a 2nd knocking sensor.

Embodiments to which the present invention is applied will be described below with reference to the drawings.
In addition, this invention is not limited to the following embodiment at all, and it cannot be overemphasized that various forms may be taken as long as it belongs to the technical scope of this invention.

[1. First Embodiment]
[1-1. overall structure]
A non-resonant type knocking sensor 1 to which the present invention is applied (hereinafter also simply referred to as “knocking sensor 1”) will be described with reference to FIG. FIG. 1 is a front view showing the appearance of the non-resonant knock sensor 1.

As shown in FIG. 1, the non-resonant type knocking sensor 1 of the present embodiment includes a case 61 that accommodates components such as the piezoelectric element 23 (see FIG. 2).
The case 61 is made of resin (specifically, PA (polyamide)).

  The case 61 includes a columnar element storage portion 63 whose upper surface side (shown on the upper side in FIG. 1; the same applies hereinafter) is tapered, and an external connector connected to an external device (for example, an ignition timing control device). And a connector portion 65 to be connected. The connector portion 65 is formed to protrude outward from the outer peripheral wall of the element storage portion 63.

  Next, the internal structure of the knocking sensor 1 will be described with reference to FIGS. FIG. 2 is a cross-sectional view showing the internal structure of the knocking sensor 1, and FIG. 3 is an explanatory view schematically showing the positional relationship of the resistance element 27, the lower surface side electrode member 17a, and the upper surface side electrode member 19a.

  As shown in FIG. 2, the knocking sensor 1 mainly includes a support member 11, a lower surface side electrode member 17a, a piezoelectric element 23, an upper surface side electrode member 19a, a weight member 31, a nut 21, a resistance element 27, and a case 61. Configured. In FIG. 2, the lower surface side insulating plate is disposed between the support member 11 and the lower surface side electrode member 17 a for insulation therebetween, and between the upper surface side electrode member 19 a and the weight member 31. An illustration of an upper-side insulating plate that is arranged and is used for insulation between the two is omitted.

The support member 11 is formed of a metal material (for example, SWCH25K carbon steel) and has an axial direction (
The piezoelectric element 23 has a cylindrical main body 12 extending in a direction when viewed from a direction orthogonal to the end face: the vertical direction in FIG. 2, and radially outward from the lower end of the main body 12 in the axial direction. It is provided with a flange 13 projecting into

  A through-hole 71 that penetrates in the axial direction is provided inside the main body 12. Further, groove portions 75 and 76 for improving adhesion to the case 61 are provided on the upper end portion of the outer peripheral surface of the main body portion 12 and the outer peripheral surface of the flange portion 13. A screw groove 74 that is screwed into the nut 21 is provided on the lower surface side of the groove portion 75 (shown below in FIG. 1; the same applies hereinafter) of the outer peripheral surface of the main body portion 12.

  The piezoelectric element 23 includes a material having a piezoelectric effect (lead zirconate titanate (PZT), various ceramics such as barium titanate, various crystals such as quartz, various organic materials such as polyvinylidene fluoride, etc.). Has been. The piezoelectric element 23 is formed in an annular shape that surrounds the outer periphery of the main body 12, and is disposed on the upper surface side of the flange 13.

The piezoelectric element 23 is provided as a signal generator for generating a knocking signal (sensor signal) that changes in response to a change in the knocking state of the internal combustion engine.
The weight member 31 is formed of an annular metal material (various metal materials such as brass). The weight member 31 is disposed on the upper surface side of the upper surface side electrode member 19 a so as to surround the outer periphery of the main body 12, and is provided to apply a load to the piezoelectric element 23.

  The nut 21 is formed of an annular metal material, and a screw groove (not shown) that is screwed into the screw groove 74 of the main body 12 is formed on the inner peripheral surface so that the nut 21 can be screwed and fixed to the main body 12. It is configured. The nut 21 has a polygonal shape (for example, a hexagonal shape) on the surface perpendicular to the axial direction, and is configured to be fastened and fixed using a tool or the like.

As shown in FIG. 3, the upper surface side electrode member 19 a includes an annular annular portion 192 and a terminal portion 191 protruding from the annular portion 192.
The annular portion 192 is formed in an annular shape that surrounds the outer periphery of the main body portion 12, and is in contact with the upper surface of the piezoelectric element 23 as shown in FIG. 2.

  The terminal portion 191 electrically connects a section from the upper surface (annular portion 192) of the piezoelectric element 23 to the connector portion 65, and is used as an energization path for an electric signal output from the upper surface of the piezoelectric element 23. The terminal portion 191 is bent on the upper surface side in accordance with the height of the connector portion 65 at a predetermined position. However, the direction in which the terminal portion 191 is bent is only the axial direction and the protruding direction of the terminal portion 191. When the upper surface side electrode member 19a is viewed from the axial direction (the state of the top view in FIG. 3), the terminal The part 191 is parallel to the virtual center line 200 and is arranged at a certain distance.

Note that the virtual center line 200 is a virtual plane on which the annular portion 192 is arranged and indicates a straight line passing through the center O of the arc drawn by the outer periphery (and the inner periphery) of the annular portion 192.
A first cutout 193 and a second cutout 194 are formed in the annular portion 192.

  The first notch 193 is formed in a region on the virtual center line 200 in the vicinity of the terminal portion 191. In addition, the first cutout 193 divides the annular portion 192 in the region on the virtual center line 200.

On the other hand, the second notch portion 194 is formed at a position facing the terminal portion 191 with respect to the center O of the annular portion 192. Moreover, the second notch 194 is set to have a shape in which the width of the annular part 192 is about half from the outer peripheral side of the annular part 192 in the region on the virtual center line 200. That is, unlike the first notch 193, the second notch 194 does not divide the annular part 192.

Next, as shown by a broken line in FIG. 3, the lower surface side electrode member 17 a includes an annular annular portion 172 and a terminal portion 171 protruding from the annular portion 172.
The annular portion 172 of the lower surface side electrode member 17a is obtained by inverting the upper surface side electrode member 19a described above about the virtual center line 200 as a central axis. That is, the annular portion 172 has the same configuration as the annular portion 192 of the upper surface side electrode member 19a, and the first notch portion 173 similar to the first notch portion 193 and the second notch portion 194 of the upper surface side electrode member 19a. (See FIG. 4) and a second notch 174 (see FIG. 4).

On the other hand, the terminal portion 171 of the lower surface side electrode member 17a differs from the terminal portion 191 of the upper surface side electrode member 19a in the length and the bent position (see FIG. 4).
And the front-end | tip part of the terminal part 171 of the lower surface side electrode member 17a is arrange | positioned so that the axial direction position may become the same as the front-end | tip part of the terminal part 191 of the upper surface side electrode member 19a in the connector part 65.

  As a result, when the lower surface side electrode member 17a and the upper surface side electrode member 19a are viewed from the axial direction, as shown in FIG. 3, the terminal portions 171 and the notches 173 and 174 of the lower surface side electrode member 17a and the upper surface side The terminal portion 191 and the cutout portions 193 and 194 of the electrode member 19a are arranged symmetrically with respect to the virtual center line 200.

Further, the terminal portion 171 of the lower surface side electrode member 17 a and the terminal portion 191 of the upper surface side electrode member 19 a are electrically connected via the resistance element 27.
The resistance element 27 functions as an abnormality detection resistor for detecting disconnection of the electrical path between the resistance element 27 and an external engine control device connected to the knocking sensor 1.

[1-2. Assembly work]
Next, assembly work of the knocking sensor 1 will be described with reference to FIG. FIG. 4 is an exploded perspective view of a part of the components provided in the knocking sensor 1. In FIG. 4, the resistor element 27 is schematically illustrated in order to represent an electrical connection state of the lower surface side electrode member 17 a, the upper surface side electrode member 19 a, and the resistor element 27.

  As shown in FIG. 4, in the assembly operation of the knocking sensor 1, first, a lower surface side insulating plate (not shown) is provided from the lower surface side toward the upper surface side so as to surround the outer periphery of the main body portion 12 in the support member 11. The lower electrode member 17a, the piezoelectric element 23, the upper electrode member 19a, the upper insulating plate (not shown), and the weight member 31 are stacked in this order.

At this time, an operation of electrically connecting the terminal portion 171 of the lower surface side electrode member 17a and the terminal portion 191 of the upper surface side electrode member 19a via the resistance element 27 is performed.
Next, an operation of screwing the nut 21 into the screw groove 74 of the support member 11 is performed, and the lower surface side insulating plate (not shown) and the lower surface side electrode member 17a are interposed between the flange portion 13 of the support member 11 and the nut 21. The piezoelectric element 23, the upper surface side electrode member 19a, the upper surface side insulating plate (not shown), and the weight member 31 are clamped and fixed.

Thereafter, these component parts are surrounded by an injection mold, and a resin containing glass fibers is injection-molded so as to cover these component parts, so that the case 61 is formed.
At this time, the case 61 is formed of an insulating material having a linear expansion coefficient in the flow direction of 2 × 10 ⁻⁵ [/ ° C.] or less. In the present embodiment, 66 nylon having a glass fiber content of 45 mass% is used as the insulating material forming the case 61. The case 61 is formed so as to cover at least the joint portion 27a between the lower surface side electrode member 17a and the resistance element 27 and the joint portion 27b between the upper surface side electrode member 19a and the resistance element 27.

In this way, the non-resonant knock sensor 1 is assembled.
Note that, in the knocking sensor 1, an end portion on the lower surface side of the flange portion 13 of the support member 11 is exposed from the lower surface side of the case 61, and an end portion on the upper surface side of the main body portion 12 of the support member 11 from the upper surface side of the case 61. Is formed to be exposed. Moreover, the connector part 65 is formed so that a part of the terminal part 171 of the lower surface side electrode member 17a and a part of the terminal part 191 of the upper surface side electrode member 19a are exposed inside.

  The non-resonant type knocking sensor 1 configured as described above has its lower surface (specifically, the lower surface of the flange portion 13 of the support member 11) hits an optimal location of the internal combustion engine (generally, the mounting portion of the cylinder block). It attaches with respect to an internal combustion engine so that it may contact.

  When abnormal vibration such as knocking occurs in the internal combustion engine, the abnormal vibration reaches the piezoelectric element 23 via the flange 13 of the support member 11, and an electric signal output from the piezoelectric element 23 in response to the abnormal vibration is generated. The output is output from the terminal portion 171 of the lower surface side electrode member 17a and the terminal portion 191 of the upper surface side electrode member 19a to an external device (for example, an engine control device).

At this time, the lower surface side electrode member 17a and the upper surface side electrode member 19a form a knocking signal transmission path.
[1-3. Measurement result]
Here, the measurement result which measured the correlation of the glass content rate and linear expansion coefficient in 66 nylon (PA66) is demonstrated. In addition, about the linear expansion coefficient, the linear expansion coefficient of the flow direction and the linear expansion coefficient of the orthogonal direction were measured, respectively.

According to the measurement result of FIG. 5, as the glass content increases, both the linear expansion coefficient in the flow direction and the linear expansion coefficient in the perpendicular direction decrease.
Note that the amount of dimensional change of the case 61 accompanying the temperature change in the installation environment of the knocking sensor is the disconnection (breakage) of the joint portion 27a between the lower surface side electrode member 17a and the resistance element 27, or the upper surface side electrode member 19a and the resistance element. In order to suppress within a range in which the disconnection (break) of the joint portion 27b with 27 does not occur, the case 61 may be formed of a material having a linear expansion coefficient in the flow direction of 2 × 10 ⁻⁵ [/ ° C.] or less.

Therefore, when the case 61 is made of 66 nylon, it is desirable to use 66 nylon having a glass content of 40% by mass or more.
Next, in order to confirm the effect of the knocking sensor 1 of the present embodiment, a measurement result obtained by measuring the resistance failure rate of the knocking sensor 1 will be described.

  In this measurement (hereinafter, also referred to as a thermal shock test), the knocking sensor 1 is heated over a plurality of cycles, with a period of 30 minutes in a 180 ° C. environment and 30 minutes in a −40 ° C. environment as one cycle. I was shocked.

Further, the resistance defect rate is the disconnection (breakage) of the joint 27a between the lower surface side electrode member 17a and the resistance element 27 or the upper surface side electrode member 19a and the resistance element 27 in the knocking sensor 1 subjected to the thermal shock test. The ratio of the knocking sensor in which the disconnection (breakage) of the joint portion 27b occurs. In other words, of the total number of knocking sensors subjected to the thermal shock test, the ratio of the number of knocking sensors in which disconnection (breakage) has occurred is the resistance failure rate.

  In the knocking sensor 1 of the present embodiment using 66 nylon having a glass fiber content of 45% by mass as a material for forming the case 61, the resistance failure rate is suppressed to 20% or less when the number of cycles is 250 or less. Thus, even when the number of cycles is 400, the resistance failure rate is suppressed to 65% or less.

[1-4. effect]
As described above, the non-resonant type knocking sensor 1 of the present embodiment includes the piezoelectric element 23 that generates a knocking signal (sensor signal), the lower surface side electrode member 17a and the upper surface side electrode member that form a knocking signal transmission path. 19a, a resistance element 27 connected to the lower surface side electrode member 17a and the upper surface side electrode member 19a, a joint portion 27a between the lower surface side electrode member 17a and the resistance element 27, and a connection between the upper surface side electrode member 19a and the resistance element 27 And a case 61 formed so as to cover at least the portion 27b.

The case 61 covers the joint portion 27a between the lower surface side electrode member 17a and the resistive element 27 and the joint portion 27b between the upper surface side electrode member 19a and the resistive element 27, and the glass fiber content is 66% by mass. Made of nylon. That is, the case 61 is made of a material having a linear expansion coefficient in the flow direction of 2 × 10 ⁻⁵ [/ ° C.] or less.

  The knocking sensor 1 including such a case 61 can suppress the dimensional change amount of the case 61 even if a temperature change occurs in the sensor installation environment, and the joint portion 27a and the joint portion 27b are disconnected due to the dimensional change of the case 61. (Breaking) can be suppressed.

  Therefore, according to the knocking sensor 1, even in an installation environment in which a temperature change occurs, disconnection (breakage) of the joint portion 27 a between the lower surface side electrode member 17 a and the resistance element 27, or between the upper surface side electrode member 19 a and the resistance element 27. The disconnection (breaking) of the joint portion 27b is unlikely to occur.

  In general, a temperature change is likely to occur at an installation location of a knocking sensor that detects knocking of the internal combustion engine. However, in the knocking sensor 1, disconnection (breakage) of the joint portion 27a or disconnection (breakage) of the joint portion 27b occurs. Therefore, the resistance element 27 can inform the external device (for example, an engine control device) of the characteristics of the knocking sensor 1.

Therefore, according to the knocking sensor 1, it becomes possible to notify an external device (for example, an engine control device) of its own characteristics, and knocking can be detected appropriately.
The knocking sensor 1 is configured such that the case 61 covers the piezoelectric element 23, the lower surface side electrode member 17a, the upper surface side electrode member 19a, and the resistance element 27.

  The knocking sensor 1 having such a configuration is configured such that the piezoelectric element 23, the lower surface side electrode member 17a, the upper surface side electrode member 19a, and the resistance element 27 are integrally provided inside the case 61, and the sensor is installed at one location. It is possible to aggregate them.

[1-5. Correspondence with Claims]
Here, the correspondence of the words in the claims and the present embodiment will be described.
The piezoelectric element 23 corresponds to an example of a signal generating part, the lower surface side electrode member 17a and the upper surface side electrode member 19a correspond to an example of a signal path part, the resistance element 27 corresponds to an example of a resistance part, and the case 61 is a resin. The knocking sensor 1 corresponds to an example of a molding unit, and the knocking sensor 1 corresponds to an example of a sensor.

[2. Other Embodiments]
As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it is possible to implement in various aspects.

For example, in the knocking sensor 1 described above, 66 nylon containing glass fiber is used as the material of the case 61. However, the resin is not limited to polyamide resin such as 66 nylon, and PPS resin or PBT resin may be used. Good. However, the material may be configured such that the linear expansion coefficient in the flow direction is 2 × 10 ⁻⁵ [/ ° C.] or less by appropriately adjusting the content of the glass fiber with respect to the resin to be used, and more preferably. Even if the material is configured such that the linear expansion coefficient in the flow direction is 2 × 10 ⁻⁵ [/ ° C.] or less and the linear expansion coefficient in the perpendicular direction is 7 × 10 ⁻⁵ [/ ° C.] or less. good.

  In a case formed of such a material, the amount of dimensional change when a temperature change occurs is limited within a certain range. For this reason, the knocking sensor provided with this case can suppress the dimensional change amount of the case even if a temperature change occurs in the installation environment, and the disconnection (breakage) of the joint portion 27a between the lower surface side electrode member 17a and the resistance element 27. In addition, disconnection (breaking) of the joint portion 27b between the upper surface side electrode member 19a and the resistance element 27 is unlikely to occur.

  Therefore, the knocking sensor provided with such a case is similar to the above-described knocking sensor 1, even in an installation environment in which a temperature change occurs, disconnection (breaking) of the joint portion 27 a between the lower surface side electrode member 17 a and the resistance element 27, The disconnection (breaking) of the joint portion 27b between the upper surface side electrode member 19a and the resistance element 27 is unlikely to occur.

  Further, the knocking sensor 1 described above is configured such that the piezoelectric element 23, the lower surface side electrode member 17a, the upper surface side electrode member 19a, and the resistance element 27 are integrally provided in the case 61. It is not restricted to such a structure. For example, as in the second knocking sensor 101 shown in FIG. 6, an element side case 163 that covers the piezoelectric element 23 (signal generation unit), a resistance element 27 (resistance unit), and a pair of electrode terminals 117 (signal path unit) are provided. The structure provided with the connector side case 165 to cover may be sufficient.

In addition, the same code | symbol is attached | subjected about the structure similar to the knocking sensor 1 among the 2nd knocking sensors 101. FIG.
In the second knocking sensor 101, the element part 141 and the connector part 143 are connected via a connection cable 145.

  The element unit 141 mainly includes a support member 11, a lower surface side electrode member 117 a, a piezoelectric element 23, an upper surface side electrode member 119 a, a weight member 31, a nut 21, and an element side case 163. Among these, the lower surface side electrode member 117a and the upper surface side electrode member 119a have the same configuration as the lower surface side electrode member 17a and the upper surface side electrode member 19a of the knocking sensor 1, and the lower surface side electrode member 117a and the upper surface side electrode member 119a Each end is electrically connected to a core wire (not shown) in the connection cable 145. In FIG. 6, a lower surface side insulating plate disposed between the support member 11 and the lower surface side electrode member 117 a for insulation between the two, and between the upper surface side electrode member 119 a and the weight member 31. An illustration of an upper-side insulating plate that is arranged and is used for insulation between the two is omitted.

  The element side case 163 is made of 66 nylon containing 45% by mass of glass fiber. The element side case 163 is formed so as to cover the support member 11, the lower surface side electrode member 117 a, the piezoelectric element 23, the upper surface side electrode member 119 a, the weight member 31, and the nut 21.

The connector part 143 mainly includes a resistance element 27 (resistance part), a pair of electrode terminals 117 (signal path part), and a connector side case 165.
The resistance element 27 is provided in a state where the pair of electrode terminals 117 are electrically connected to each other. The pair of electrode terminals 117 is electrically connected to the lower surface side electrode member 117a and the upper surface side electrode member 119a via a core wire (not shown) of the connection cable 145.

Similar to the case 61, the connector side case 165 is formed of a material (resin material) having a linear expansion coefficient in the flow direction of 2 × 10 ⁻⁵ [/ ° C.] or less. That is, as a material for forming the connector side case 165, 66 nylon having a glass fiber content of 45 mass% is used. The connector side case 165 is formed so as to cover at least the joint 127a between the one electrode terminal 117 and the resistance element 27 and the joint (not shown) between the other electrode terminal 117 and the resistance element 27. .

  Similar to the knocking sensor 1, the second knocking sensor 101 having such a configuration can suppress the dimensional change amount of the connector-side case 165 even if a temperature change occurs in the sensor installation environment, and the pair of electrode terminals 117 and It is possible to suppress disconnection (breaking) of the joint portion 127a with the resistance element 27 due to a dimensional change of the connector side case 165.

  Therefore, according to the second knocking sensor 101, even in an installation environment in which a temperature change occurs, disconnection (breaking) of the joint 127a between the pair of electrode terminals 117 and the resistance element 27 is unlikely to occur.

Here, the correspondence relationship between the claims and the second knocking sensor 101 will be described.
The piezoelectric element 23 corresponds to an example of a signal generation unit, the pair of electrode terminals 117 corresponds to an example of a signal path unit, the resistance element 27 corresponds to an example of a resistance unit, and the connector side case 165 is an example of a resin molding unit. The second knocking sensor 101 corresponds to an example of the sensor.

  The sensor of the present invention is not limited to a knocking sensor, and may be a sensor that detects a change in the state of a measurement target other than knocking, such as a gas sensor or a temperature sensor. Among such sensors, the present invention can be applied to any sensor provided with a resistance portion connected to the signal path portion.

  DESCRIPTION OF SYMBOLS 1 ... Non-resonance type knocking sensor, 11 ... Support member, 12 ... Main-body part, 13 ... Gutter part, 17a ... Lower surface side electrode member, 19a ... Upper surface side electrode member, 21 ... Nut, 23 ... Piezoelectric element, 27 ... Resistance element 27a ... joining portion, 27b ... joining portion, 31 ... weight member, 61 ... case, 63 ... element housing portion, 65 ... connector portion, 101 ... second knocking sensor, 117 ... electrode terminal, 117a ... bottom surface side electrode member, 119a: Upper surface side electrode member, 127a: Joining portion, 141 ... Element portion, 143 ... Connector portion, 145 ... Connection cable, 163 ... Element side case, 165 ... Connector side case.

Claims (4)

A signal generator that generates a sensor signal that changes in response to a change in the state of the measurement target;
A signal path portion forming a transmission path of the sensor signal;
A resistor connected to the signal path;
A resin molded part that is molded with resin and covers at least a connection part between the signal path part and the resistance part;
A sensor comprising:
The resin molded part contains glass fiber and is formed of a material having a linear expansion coefficient in the flow direction of 2 × 10 ⁻⁵ [/ ° C.] or less,
Sensor characterized by. A signal generator that generates a sensor signal that changes in response to a change in the state of the measurement target;
A signal path portion forming a transmission path of the sensor signal;
A resistor connected to the signal path;
A resin molded part that is molded with resin and covers at least a connection part between the signal path part and the resistance part;
A sensor comprising:
The resin molded part contains glass fiber, and the linear expansion coefficient in the flow direction is 2 × 10 ⁻⁵ [/ ° C.] or less, and the linear expansion in the direction perpendicular to the flow direction is perpendicular to the flow direction. A rate of 7 × 10 ⁻⁵ [/ ° C.] or less;
Sensor characterized by. The resin molding part covers the signal generation part, the signal path part, and the resistance part,
The sensor according to claim 1 or 2, wherein The signal generator is a piezoelectric element,
The measurement object is knocking of an internal combustion engine;
The sensor according to any one of claims 1 to 3, wherein:

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