JP2006343324A - Method and device for inspecting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for inspecting a structure for detecting the existence of a defect of the ceramic member by effectively utilizing the vibration caused by the load activating the ceramic member in the production process of the structure fixed with the ceramic member in the housing. <P>SOLUTION: In the talk pressing process in the manufacturing process of the gas sensor, the talk ring 130 of the sensor main body 100 is pressed down by the die 330 of the hydraulic press 300, the vibration wave generated by the sensor main body 100 is detected by the AE sensor 400 as a vibration signal, the prescribed vibration discrimination sinal is discriminated from the vibration signal. Out of the vibration discrimination signal, the vibration wave discrimination signal is counted which is detected within a counting period in an elapse of a standby interval after a die 330 of the hydraulic press 300 arrived at the prescribed position, and the existence of the defect of the insulation member is examined from the counted value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure inspection method and an inspection apparatus.

Conventionally, for example, there is a method for inspecting a ceramic sintered body disclosed in Patent Document 1 below. In this inspection method, a load is applied to a test piece of a ceramic sintered body, the test piece is subjected to a bending test, and an acoustic emission wave signal generated from the test piece is counted in accordance with the bending test, and thus counted. Focusing on a signal having a peak value in a specific frequency region corresponding to the material of the test piece in the acoustic emission wave signal, the defect of the test piece is inspected based on this signal.
Japanese Patent Laid-Open No. 63-243753

  By the way, in the above-described method for inspecting a ceramic sintered body, when performing a bending test of a test piece as described above, a shock wave signal is generated from the test piece due to an impact generated when a load is applied to the test piece. appear.

  However, this shock wave signal has no relation to the defect of the test piece, unlike the acoustic emission wave signal generated due to the bending of the test piece by the bending test. Therefore, even if the shock wave signal generated from the test piece due to the impact generated when a load is applied to the test piece is counted, the defect of the test piece cannot be correctly inspected depending on the counting result. There is a problem that.

  Therefore, in order to cope with the above-described problems, the present invention applies a load to the structure so that the load is applied to the ceramic member in the manufacturing process of the structure in which the ceramic member is fixed inside the housing. It is an object of the present invention to provide a structure inspection method and an inspection apparatus for effectively inspecting the presence or absence of damage to the ceramic member by effectively utilizing vibration waves generated from the structure.

In solving the above problems, in the structure inspection method according to the present invention, according to the description of claim 1,
Structured by load applying means (300) so that a load is applied to the ceramic member in one step of the manufacturing process of the structure (100, 201) in which the ceramic member (121) is fixed inside the housing (110). When a load is applied to the body, the vibration wave generated from the structure is detected as a vibration wave signal.
Of the vibration wave signal, the vibration wave signal detected within a predetermined counting period after a predetermined waiting period has elapsed since the load applying means has reached a predetermined position,
The ceramic member is inspected for damage based on the count value of the vibration wave signal.

  With this configuration, when a load is applied to the structure so that a load is applied to the ceramic member in one step of the structure manufacturing process in which the ceramic member is fixed inside the housing, When the ceramic member is damaged, the vibration wave generated along with the damage is detected as a vibration wave signal, and the predetermined value after the predetermined standby period elapses after the load applying means is in the predetermined position of the vibration wave signal. The vibration wave signals detected within the counting period are counted, and the presence or absence of damage to the ceramic member is inspected based on the count value of the vibration wave signal.

  Here, as described above, only the vibration wave signals detected within a predetermined counting period after a predetermined waiting period has elapsed since the load applying means has reached a predetermined position among the vibration wave signals are counted. Therefore, even if a shock wave signal is detected because a shock wave is generated based on the shock generated when the load is applied to the structure as described above, the shock wave signal is detected before the standby period has elapsed. It is not counted because it occurs.

  For this reason, it is not mistaken that the ceramic member is damaged due to a shock wave signal generated when a load is applied to the structure. As a result, the presence or absence of damage to the ceramic member can be correctly inspected based on the number of vibration wave signals counted in one process described above.

  In particular, even if the damage to the ceramic member cannot be visually recognized from the outside of the structure, an effect that the damage to the ceramic member can be correctly recognized can be achieved.

According to the second aspect of the present invention, in the structure inspection method according to the first aspect,
The vibration wave is compared with a predetermined threshold, and a vibration wave signal that is equal to or higher than the threshold is discriminated as a vibration wave discrimination signal.
The vibration wave discrimination signal detected within the counting period among the vibration wave discrimination signals is counted,
The inspection of whether the ceramic member is damaged is performed by checking whether the count value of the vibration wave discrimination signal has reached a predetermined value.

  As described above, the vibration wave signal having a predetermined threshold value or more among the vibration wave signals is discriminated as the vibration wave discrimination signal, and whether or not the ceramic member is damaged depends on whether or not the count value of the vibration wave discrimination signal reaches the predetermined value. By examining the above, the effect of the invention of claim 1 can be achieved more specifically.

According to a third aspect of the present invention, in the structure inspection method according to the first or second aspect,
In the structure, a housing is arranged so as to surround the periphery of the ceramic member, and the housing and the ceramic member are fixed by compressing and filling inorganic powder between the housing and the ceramic member.
One step of the manufacturing process is characterized in that the inorganic powder filled between the housing and the ceramic member is compressed by a load applying means.

  When the housing is arranged as a structure so as to surround the ceramic member, and the housing and the ceramic member are fixed by compressing and filling inorganic powder between the housing and the ceramic member, the housing and the ceramic member In the process of compressing the inorganic powder filled between the two, the ceramic member is likely to be damaged. For this reason, the presence or absence of damage to the ceramic member can be reliably inspected by applying the present invention to the manufacturing process of the structure having the above-described configuration.

According to the description of claim 4, the present invention provides the structure inspection method according to claim 3,
The ceramic member has a cylindrical shape or a plate shape.

  When the ceramic member is cylindrical or plate-shaped, the ceramic member is easily damaged when the ceramic member is fixed to the housing. For this reason, the presence or absence of damage to the ceramic member can be reliably inspected by applying the present invention to the manufacturing process of the structure formed by fixing the ceramic member having such a shape.

Further, according to the fifth aspect of the present invention, in the structure inspection method according to any one of the first to fourth aspects,
The structure is a gas sensor.

  By applying the present invention to a gas sensor, it is possible to reliably inspect the ceramic member for damage in the manufacturing process of the gas sensor.

Moreover, according to the description of Claim 6, the structure inspection apparatus according to the present invention is provided.
Structured by a load applying means (300) so as to apply a load to the ceramic member in one of the manufacturing steps of the structure (100, 201) in which the ceramic member (121) is fixed inside the housing (110). Vibration wave detecting means (400) for detecting a vibration wave generated from the structure as a vibration wave signal when a load is applied to the body;
Position detecting means (460) for detecting the position of the load applying means and generating a position detection signal;
Delay signal generating means (470) for generating a delay signal for a predetermined time when the position detection signal reaches a predetermined value;
Counting means (480) for counting vibration wave signals detected within a predetermined counting period after the generation period of the delay signal among vibration wave signals;
According to the count value of the counting means, there is provided a notifying means (490) for notifying that the ceramic member is damaged.

  With this configuration, it is possible to provide a structure inspection apparatus that can achieve substantially the same function and effect as the first aspect of the invention.

According to the seventh aspect of the present invention, in the structure inspection apparatus according to the sixth aspect,
A discrimination means (450) for comparing the vibration wave signal with a predetermined threshold and discriminating a vibration wave signal equal to or higher than the threshold as a vibration wave discrimination signal,
The counting means counts the vibration wave discrimination signal detected within the counting period among the vibration wave discrimination signals discriminated by the discrimination means,
The notifying means is characterized by notifying when the count value of the vibration wave discrimination signal counted by the counting means reaches a predetermined value.

  As described above, when the vibration wave discrimination signal is discriminated by comparing the vibration wave signal with a predetermined threshold, and when the count value of the vibration wave discrimination signal counted by the counting means reaches a predetermined value. By notifying, the effect of the invention of claim 6 can be achieved more specifically.

Moreover, according to the description of Claim 8, this invention is the structure inspection apparatus of Claim 6 or Claim 7,
In the structure, a housing is arranged so as to surround the periphery of the ceramic member, and the housing and the ceramic member are fixed by compressing and filling inorganic powder between the housing and the ceramic member.
One step of the manufacturing process is characterized in that the inorganic powder filled between the housing and the ceramic member is compressed by a load applying means.

  With this configuration, it is possible to provide a structure inspection apparatus that can achieve substantially the same function and effect as the third aspect of the invention.

According to the description of claim 9, the present invention provides the structure inspection apparatus according to claim 8,
The ceramic member has a cylindrical shape or a plate shape.

  With this configuration, it is possible to provide a structure inspection apparatus that can achieve substantially the same operation and effect as the fourth aspect of the invention.

According to a tenth aspect of the present invention, in the structure inspection apparatus according to any one of the sixth to ninth aspects,
The structure is a gas sensor.

  With this configuration, it is possible to provide a structure inspection apparatus that can achieve substantially the same effect as that of the fifth aspect of the invention.

  In addition, the code | symbol in the parenthesis of each said means shows a corresponding relationship with the specific means as described in the implementation shape mentioned later.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example in which an inspection apparatus according to the present invention is applied to a gas sensor.

  Prior to describing the configuration of the inspection apparatus, a manufacturing process of a gas sensor to which the inspection apparatus is applied will be described. The gas sensor is manufactured through a manufacturing process including a plurality of processes. The manufacturing process includes a talc pressing process and a heat caulking process as main processes.

  First, the talc holding process will be described. This talc pressing process corresponds to a process for ending the manufacture of the main body 100 (see FIG. 2) of the gas sensor.

  In the process of manufacturing the gas sensor main body 100 (hereinafter also referred to as the sensor main body 100) up to the talc pressing process, as shown in FIG. 3, as shown in FIG. The element intermediate body 120, the talc ring 130, and the cylindrical protector 140 are prepared.

  Here, the element intermediate 120 is formed by coaxially fitting a cylindrical insulating member 121 made of ceramic in an intermediate portion of the plate-shaped sensor element unit 122. The ceramic sensor element unit 122 is formed by bonding a plate-shaped ceramic heater to a plate-shaped ceramic sensor element.

  Therefore, the tip portions of the ceramic heater and the sensor element extend from the tip portion of the insulating member 121 as the tip portion 123 of the sensor element unit 122 (see FIG. 3).

  After preparation as described above, the plate-like packing 124 is inserted into the metal shell 110 from its proximal end opening 111. Thereafter, the element intermediate 120 is coaxially inserted into the metal shell 110 from the proximal end opening 111 at the distal end 123 thereof. By this insertion, the element intermediate body 120 extends from the front end opening 112 through the metal shell 110 at the front end 123.

  Next, the protector 140 is coaxially fixed to the front end opening 112 of the metal shell 110 by welding so as to cover the front end 123 of the sensor element unit 122 at the opening. Thereafter, the talc ring 130 passes through the element intermediate body 120 coaxially, and is coaxially fitted into the metal shell 110 from the base end opening 111 thereof.

  By this fitting, the talc ring 130 made of inorganic powder is coaxially interposed between the inner peripheral wall of the metal shell 110 and the peripheral wall tip of the insulating member 121. Thereby, the manufacture of the sensor main body 100 before the talc pressing process shown in FIG. 2 is completed.

  Thereafter, the talc pressing process is performed. This talc pressing process is performed using a hydraulic device 300 shown in FIG.

  Here, the configuration of the hydraulic device 300 will be described (see FIG. 6 or FIG. 8). The hydraulic apparatus 300 includes a cylinder 310 and a piston (not shown). The piston is fitted in the cylinder 310 so as to be axially movable, and upper and lower hydraulic chambers are defined in the cylinder 310. is doing. Of the upper and lower hydraulic chambers, the upper hydraulic chamber is located at the upper portion of the cylinder 310 shown in FIG. 6, and of the upper and lower hydraulic chambers, the lower hydraulic chamber is shown in FIG. It is located in the lower part of the figure.

  The piston has a piston rod (not shown). The piston rod passes through the lower hydraulic chamber and extends coaxially from the piston and is connected to the support plate 320. A cylindrical mold 330 is coaxially and detachably mounted on the support plate 320 and extends toward the positioning substrate 340. This mounting is done by screwing the annular flange 331 of the mold 330 to the support plate 320.

  In the present embodiment, the mold 330 has an inner diameter somewhat larger than the outer diameter of the insulating member 121 and an outer diameter somewhat smaller than the inner diameter of the metal shell 110. Here, the mold 330 is formed of a metal material such as carbon steel (for example, SKS3). Further, as shown in FIGS. 6 and 8, the positioning substrate 340 is installed horizontally just below the cylinder 310. The positioning substrate 340 is an abbreviation of a metal such as carbon steel (for example, S45C). A square plate material is used to form a predetermined thickness (see FIG. 7).

  The cylinder 310 is connected to the switching valve 350 via upper and lower hydraulic pipes 311 and 312 in the upper and lower hydraulic chambers. The switching valve 350 supplies hydraulic pressure from a hydraulic source (not shown) to the upper hydraulic chamber via the upper hydraulic pipe 311 in accordance with the switching operation to one side of the switching rod 351, and at the same time the lower hydraulic chamber. Is discharged from the lower hydraulic pipe 312 and returned to the hydraulic pressure source. Accordingly, the mold 330 is displaced toward the positioning substrate 340 in accordance with the downward axial movement of the piston in the cylinder 310.

  On the other hand, the switching valve 350 supplies the hydraulic pressure from the hydraulic source to the lower hydraulic chamber via the lower hydraulic pipe 312 in accordance with the switching operation to the other side of the switching rod 351, and the hydraulic pressure in the upper hydraulic chamber. Is discharged from the upper hydraulic pipe 311 and returned to the hydraulic pressure source. Accordingly, the mold 330 is displaced upward on the positioning substrate 340 side in accordance with the upward axial movement of the piston in the cylinder 310.

  Therefore, in the talc pressing process, the pressing process for the talc 130 is performed as follows under the hydraulic device 300 configured as described above. As described above, the sensor main body 100 manufactured before the talc pressing process is inserted from the protector 140 through the annular jig 341 and through the through hole 342 formed in the positioning substrate 340 as shown in FIG. Let

  As a result, the sensor body 100 is erected by being coaxially seated on the jig 341 at the large diameter portion of the metal shell 110. At this time, the mold 330 is positioned coaxially with the insulating member 121 immediately above the insulating member 121.

  In such a state, when the switching rod 351 of the switching valve 350 is switched to one side thereof, along with the supply of the hydraulic pressure into the upper hydraulic chamber of the cylinder 310 and the discharge of the hydraulic pressure from the lower hydraulic chamber, The mold 330 is displaced downward together with the support plate 320 as the piston moves downward.

  Therefore, the mold 330 is displaced from the base end side of the sensor element unit 122 while being coaxially fitted to the insulating member 121 from the outside. Along with this displacement, the mold 330 is inserted into the metal shell 110 at the front end portion 332 and collides with the upper end portion of the talc ring 130.

  At this time, at least one of the talc ring 130 and the mold 330 instantaneously generates elastic strain due to the impact caused by the collision. Then, due to this instantaneous elastic strain, a shock wave is generated in the sensor main body 100 around the collision portion between the talc ring 130 and the mold 330.

  After the mold 330 collides with the talc ring 130 in this way, as described above, when the supply of the hydraulic pressure into the upper hydraulic chamber of the cylinder 310 and the discharge of the hydraulic pressure from the lower hydraulic chamber are further continued, the mold 330 continuously pressurizes the talc ring 130 by its tip 332. Thereby, the talc ring 130 is pressed in the metal shell 110 by the mold 330.

  When the switching rod 351 of the switching valve 350 is switched in the other direction after the talc ring 130 is pressed in this way, the supply of hydraulic pressure to the lower hydraulic chamber of the cylinder 310 and the hydraulic pressure from the upper hydraulic chamber are performed. With the discharge, the mold 330 is displaced upward together with the support plate 320 along with the upward axial movement of the piston, and returns to the original position. Thereby, the talc pressing process is completed, and the manufacture of the sensor body 100 after the talc pressing process is completed.

  Next, the heat caulking process will be described. This thermal caulking process corresponds to a process for ending the manufacturing of the substantially completed product 200 (see FIG. 9) of the gas sensor in the manufacturing process of the gas sensor.

  In the process before the heat caulking process, in addition to the sensor body 100 after the talc pressing process described above, a caulking ring 210, a ring packing 220, and a cylindrical outer cylinder 230 are prepared (see FIG. 5).

  After the preparation as described above, the caulking ring 210 is fitted into the metal shell 110 through the sensor body 100 after the talc holding step. By this fitting, the caulking ring 210 is coaxially interposed between the inner peripheral wall of the metal shell 110 and the peripheral wall tip of the insulating member 121 and is seated on the talc ring 130.

  Next, the outer cylinder 230 is coaxially passed through the sensor main body 100 after the talc pressing process and fitted toward the metal shell 110. By this fitting, the outer cylinder 230 is seated on the caulking ring 210 at the front end portion 231 between the inner peripheral wall of the metal shell 110 and the front end portion of the peripheral wall of the insulating member 121.

  Thereafter, the ring packing 220 is coaxially passed through the sensor body 100 after the talc pressing process and fitted into the metal shell 110. By this fitting, the ring packing 220 is coaxially interposed between the inner peripheral wall of the metal shell 110 and the front end side peripheral wall of the outer cylinder 230 and is seated on the front end portion 231 of the outer cylinder 230.

  As a result, the sensor structure 201 in a state prior to thermal crimping is manufactured as shown in FIG.

  Thereafter, a heat caulking process is performed. The heat caulking process is performed using the hydraulic device 300 described above. However, a new mold 360 is coaxially mounted on the support plate 320 as shown in FIG. 8 instead of the mold 330. This mounting is performed by screwing the annular flange 361 of the mold 360 to the support plate 320. The mold 360 has an inner diameter that is somewhat larger than the outer diameter of the outer cylinder 230 and an outer diameter that is somewhat larger than the outer diameter of the proximal end opening 111 of the metal shell 110. The mold 360 is formed of a metal material such as hard beryllium copper (for example, BeA-25).

  In the thermal caulking process, after removing the sensor body 100 after the talc process from the jig 341, the sensor structure 201 manufactured in the process before the thermal caulking process as described above is removed from the protector 140 side. As shown in FIG. 8, the jig 341 is passed through the through hole 342 of the positioning substrate 340.

  Accordingly, the sensor structure 201 is erected while being coaxially seated on the jig 341 at the large-diameter portion of the metal shell 110. At this time, the mold 360 is positioned coaxially with the outer cylinder 230 immediately above the outer cylinder 230 of the sensor structure 201.

  In such a state, when the switching rod 351 of the switching valve 350 is switched to one side in the same manner as described above, the supply of the hydraulic pressure to the upper hydraulic chamber of the cylinder 310 and the hydraulic pressure from the lower hydraulic chamber are performed. Along with the discharge, the mold 360 is displaced downward together with the support plate 320 based on the downward axial movement of the piston. For this reason, the mold 360 is displaced from the base end side of the sensor structure 201 while being coaxially fitted to the outer cylinder 230 from the outside. With this displacement, the mold 360 collides with the proximal end opening 111 of the metal shell 110 at the distal end 362 thereof.

  At this time, at least one of the metallic shell 110 and the mold 360 instantaneously generates elastic strain due to the impact caused by the collision. Then, due to this instantaneous elastic strain, a shock wave is generated in the sensor structure 201 around the collision portion between the metal shell 110 and the mold 360. Note that the sensor structure 201 is heated by energizing the metal shell 110 during the heat caulking process.

  After such a collision with the metal shell 110 of the mold 360, when the supply of the hydraulic pressure into the upper hydraulic chamber of the cylinder 310 and the discharge of the hydraulic pressure from the lower hydraulic chamber are further continued as described above, 360 continuously pressurizes the proximal end opening 111 of the metallic shell 110 by the distal end portion 362. As a result, the base end opening 111 of the metal shell 110 is caulked as in the circle 113 shown in FIG. 9, and the manufacture of the finished product 200 is completed.

  In the present embodiment, the inspection by the inspection apparatus shown in FIG. 1 is performed in accordance with the talc pressing process and the heat caulking process described above in the manufacturing process of the gas sensor. Therefore, the configuration of the inspection apparatus will be described with reference to FIG.

  The inspection apparatus includes an acoustic emission sensor 400 (hereinafter also referred to as an AE sensor 400). The AE sensor 400 is attached to a positioning substrate 410 via an annular boss 420 as shown in FIG. 6 or FIG. Has been. Here, the positioning substrate 410 is formed in the same shape as the positioning substrate 340 with the same forming material as that of the positioning substrate 340, and the positioning substrate 410 has one end portion 411 and one end portion of the positioning substrate 340. Similarly to the positioning substrate 340, it is disposed horizontally so as to come into contact with 343 in a surface contact state (see FIG. 7).

  The annular boss 420 is configured by coaxially extending the annular boss portion 422 from the flange portion 421. Thus, the boss 420 is mounted so as to be coaxially positioned on the positioning substrate 410 at the flange portion 421.

  As shown in FIG. 10, the AE sensor 400 includes a casing 430. The casing 430 includes a substantially cylindrical peripheral wall 431, a disk-shaped lid 432 provided at an upper end opening of the peripheral wall 431, and a peripheral wall. A disc-shaped receiving plate 433 provided as a bottom plate at the lower end opening of 431 is configured. Thus, the casing 430 is coaxially fitted to the boss 420 at the bottom as shown in FIG. 6 or FIG.

  The receiving plate 433 is made of ceramic, and the receiving plate 433 is in uniform contact with the upper surface of the positioning substrate 410 and receives a vibration wave via the positioning substrate 410 in the thickness direction as will be described later. Vibrate.

  The AE sensor 400 includes a piezoelectric body 434 made of ceramic, and the piezoelectric body 434 is erected on the receiving plate 433 in the casing 430. The piezoelectric body 434 exhibits a piezoelectric conversion action in accordance with the vibration of the receiving plate 433, generates a piezoelectric voltage as a detection voltage (hereinafter also referred to as a detection voltage of the AE sensor 400), and outputs it via the lead wire 435. The lead wire 435 extends from the piezoelectric body 434 into a cylindrical portion 436 provided in a part of the peripheral wall 431.

  As shown in FIG. 1, the inspection apparatus includes a preamplifier 440 and a signal discrimination unit 450. The preamplifier 440 amplifies the detection voltage of the AE sensor 400 and outputs it to the signal discrimination unit 450.

  The signal discrimination unit 450 includes a high-pass filter 451 (hereinafter also referred to as HPF 451), an amplifier 452, a detector 453, and a signal discriminator 454. The HPF 451 receives a detection voltage from the AE sensor 400 via the lead wire 435 and the preamplifier 440, and outputs a low frequency component having a predetermined frequency (for example, 20 (kHz)) or less among the frequency components of the detection voltage. The remaining frequency component is generated as a filter voltage. In the present embodiment, the low-frequency component refers to a component including a disturbance frequency such as noise.

  The amplifier 452 amplifies the filter voltage from the HPF 451 and generates it as an amplified voltage. The detector 453 detects a predetermined detection component (that is, a predetermined vibration wave component) from the amplified voltage from the amplifier 452, and generates a detection signal. Here, the predetermined detection component is a vibration wave generated from the sensor body 100 or the sensor structure 201 after the collision with the talc ring 130 or the metal shell 110 of the mold 330 or 360 in the talc pressing process or the thermal caulking process. Corresponds to the ingredient.

  The signal discriminator 454 sequentially discriminates signal components having a predetermined threshold value or more from the detection signal from the detector 453 and generates a discrimination signal (vibration wave discrimination signal). Here, the predetermined threshold is set to a predetermined value, and the predetermined value is used when there is a possibility that the insulating member 121 is cracked as described later in the talc pressing process or the heat caulking process. Corresponds to the value of the detection signal.

  The inspection apparatus also includes a position sensor 460, a delay circuit 470, a counter 480, and a buzzer circuit 490. The position sensor 460 is supported in the vicinity of the proximal end opening 111 of the metal shell 110 of the sensor main body 100 or sensor structure 201 as shown in FIG. 6 or FIG. The position sensor 460 detects the tip when the die 330 or 360 of the cylinder device 300 is displaced to the descending end at the tip, and generates a position detection signal.

  The delay circuit 470 generates a delay signal at a high level based on the position detection signal from the position sensor 460. The signal width of this delayed signal is set to a predetermined width. In the present embodiment, the predetermined width is determined from the generation period of a shock wave generated by an impact caused by a collision with the talc ring 130 of the mold 330 or a collision with the base end opening 111 of the metal shell 110 of the mold 360 as described later. Corresponds to a somewhat longer predetermined time. Note that a period in which a high-level delay signal is generated from the delay circuit 470 corresponds to a standby period.

  The counter 480 is reset-started based on the fall of the delay signal from the delay circuit 470 to a low level, counts the discrimination signal generated sequentially from the signal discriminator 454, and counts when the count value reaches a predetermined value. Generate a signal. Note that a period during which a low-level delay signal is generated from the delay circuit 470 corresponds to a counting period.

  However, the predetermined value corresponds to the number of discrimination signals when there is a possibility that the insulating member 121 is cracked in the above-described talc pressing process or thermal caulking process as described later. The buzzer circuit 490 sounds a buzzer based on the count signal from the counter 480.

  The inspection in the talc pressing process and the heat caulking process described above will be described using the inspection apparatus configured as described above.

  When the manufacturing process of the gas sensor is performed in the talc pressing process as described above, in the hydraulic apparatus 300, as shown in FIG. 6, the mold 330 is mounted on the support plate 320, and the sensor main body before the talc pressing process is performed. 100 is erected on the positioning substrate 340 via the jig 341. At this time, the positioning substrate 410 on which the AE sensor 400 is mounted as described above is in contact with the one end portion 343 of the positioning substrate 340 in a surface contact state at one end portion 411 thereof.

  In such a state, as described in the above-described talc pressing process, when the mold 330 is displaced downward and collides with the upper end of the talc ring 130 at the front end 332 thereof, the mold 330 is concerned. Is positioned at the lower end at its tip 332. Therefore, the position sensor 460 detects the tip end portion 332 of the mold 330 and generates a position detection signal.

  Along with this, the delay circuit 470 generates a delay signal based on the position detection signal from the position sensor 460 and inputs it to the counter 480. In such a state, since the delay signal is at a high level (waiting period), the counter 480 is not reset-started.

  When the mold 330 collides with the talc ring 130 as described above, the sensor body 100 before the talc pressing process generates a shock wave as described above. The shock wave generated in this way propagates from the sensor main body 100 before the talc pressing process to the positioning substrate 340 via the jig 341.

  The shock wave thus propagated propagates from the positioning substrate 340 to the receiving plate 433 of the AE sensor 400 through the positioning substrate 410. Here, since the positioning substrates 340 and 410 are in a surface contact state as described above, the propagation of the shock wave from the positioning substrate 340 to the positioning substrate 410 is favorably performed.

  When the shock wave propagates to the receiving plate 433 as described above, the receiving plate 433 vibrates in the plate thickness direction according to the frequency of the shock wave. Then, the piezoelectric element 434 generates a piezoelectric voltage with the vibration of the receiving plate 433 and outputs the piezoelectric voltage to the preamplifier 440 through the lead wire 435.

  Next, the preamplifier 440 amplifies the piezoelectric voltage from the piezoelectric element 434 and outputs it to the signal discrimination unit 450. Accordingly, in the signal discrimination unit 450, the predetermined low frequency component of the amplified voltage of the preamplifier 440 is removed by the HPF 451, and the remaining frequency component is output to the amplifier 452 as a filter voltage. .

  Along with this, the filter voltage is amplified by the amplifier 452 and output to the detector 453 as an amplified voltage. Then, the detector 453 detects the detection component from the amplified voltage of the amplifier 452, generates a detection signal, and outputs the detection signal to the signal discriminator 454.

  Therefore, the signal discriminator 454 compares the detection signal with the predetermined threshold value to discriminate. Here, if the signal discriminator 454 generates a discrimination signal based on the detection signal generated from the detector 453 in response to the shock wave caused by the collision with the talc ring 130 of the mold 330, the discrimination signal is output to the counter 480. The

  At such a stage, as described above, the counter 480 is not reset-started (the standby period), so the counter 480 does not count the discrimination signal.

  Thereafter, when the shock wave caused by the collision of the mold 330 with the talc ring 130 disappears and the delay signal from the delay circuit 470 becomes low level, the counter 480 is reset and started to start counting.

  Further, even after the mold 330 collides with the talc ring 130 as described above, a downward displacement force is continuously applied to the mold 330, so that the talc ring 130 is moved to the tip by the mold 330. It is pressed so as to press downward at the part.

  For this reason, the insulating member 121 is pressed in the radial direction by the talc ring 130 to cause elastic distortion. This elastic strain increases as the pressing force against the insulating member 121 increases. When the elastic strain reaches a strain that exceeds the elastic limit of the insulating member 121, the insulating member 121 may be broken. In addition, as a shape of a crack, there exist a ring-shaped crack generate | occur | produced over the perimeter of the circumferential direction of the cylindrical insulating member 121, and a partial crack.

  In such a process, the insulating member 121 generates a vibration wave according to an increase in its elastic strain. Here, the frequency of the vibration wave belongs to a specific frequency range generated due to the elastic strain of the insulating member 121.

  Further, the amplitude of the vibration wave increases as the elastic strain of the insulating member 121 increases. This means that the amplitude of the vibration wave is maximized when the insulating member 121 is cracked.

  As described above, the vibration wave generated due to the pressing of the talc ring 130 propagates from the sensor main body 100 during the talc pressing process to the positioning substrate 340 via the jig 341, as in the case of the shock wave described above. In the same manner as described above, the light propagates well through the positioning substrate 410 to the receiving plate 433 of the AE sensor 400.

  Then, the receiving plate 433 vibrates in the plate thickness direction according to the frequency of the vibration wave generated as described above, and accompanying this vibration, the piezoelectric element 434 exhibits a piezoelectric action, generates a piezoelectric voltage, and leads. Output to preamplifier 440 via line 435. Here, the piezoelectric voltage generated from the piezoelectric element 434 is different from the piezoelectric voltage corresponding to the above-described shock wave.

  Thus, the preamplifier 440 amplifies the piezoelectric voltage from the piezoelectric element 434 and outputs it to the signal discrimination unit 450. Accordingly, in the signal discrimination unit 450, the predetermined low frequency component of the amplified voltage of the preamplifier 440 is removed by the HPF 451 as described above, and the remaining frequency component is amplified as a filter voltage. 452 is output.

  Then, in the same manner as described above, the filter voltage is amplified by the amplifier 452, and then detected by the detector 453 and output to the signal discriminator 454 as a detection signal. Along with this, the signal discriminator 454 discriminates the detection signal from the detector 453 by comparing it with the predetermined threshold, sequentially generates the discrimination signal, and outputs it to the counter 480.

  At this time, as described above, the counter 480 has already been reset and started and is in a counting state (counting period). Therefore, the counter 480 counts the discrimination signals sequentially output from the signal discriminator 454.

  When the count value of the counter 480 reaches the predetermined value accompanying such counting, the counter 480 generates a count signal and outputs it to the buzzer circuit 490. For this reason, the buzzer circuit 490 sounds the buzzer.

  Thereby, it turns out that the sensor main body 100 after the talc pressing process is a defective product due to cracking of the insulating member 121 or the like. As a result, such a sensor body 100 is not used in the heat caulking process.

  On the other hand, if the signal discriminator 454 does not generate a discrimination signal, or if the count value of the counter 480 does not reach the predetermined value even if the signal discriminator 454 generates a discrimination signal, the counter 480 does not generate a count signal. . Therefore, the buzzer of the buzzer circuit 490 does not sound. Thereby, it turns out that the sensor main body 100 after a talc pressing process is a good product. As a result, such a sensor main body 100 is used for a heat caulking process.

  As described above, when a crack occurs in the insulating member 121 due to the pressing of the talc ring 130 in the talc pressing process, a vibration wave generated along with the crack is detected by the detection device with the AE sensor 400, The detection output is sequentially discriminated as a discrimination signal by the signal discrimination unit 450 as described above, the discrimination signal is counted by the counter 480, and when the count value reaches the predetermined value, the buzzer circuit 490 Let it ring.

  Here, as described above, even if the signal discriminating unit 450 may generate a discrimination signal due to a shock wave generated by the collision with the talc ring 130 of the mold 330 as described above, the delay circuit 470 Based on the position detection signal generated from the position sensor 460 when the mold 330 is displaced to the descending end, a delay signal is generated at a high level and the reset start of the counter 480 is prohibited, so that the buzzer of the buzzer circuit 490 sounds. There is no.

  As a result, the insulating member 121 is not mistakenly cracked due to a shock wave caused by a collision with the talc ring 130 of the mold 330. Therefore, based on the ringing of the buzzer 490 in the talc pressing process, it can be correctly recognized that the insulating member 121 has cracked due to the pressing of the talc ring 130.

  In particular, even if the insulation member 121 is not visible because the crack has occurred inside the metal shell 110, it can be correctly recognized that the insulation member 121 has cracked.

  Next, an example in which inspection is performed in the above-described thermal caulking process using the sensor body 100 will be described.

  As described in the above-described thermal crimping process, in the hydraulic apparatus 300, the mold 360 is mounted on the support plate 320 instead of the mold 330, and the sensor structure 201 using the sensor main body 100 as a non-defective product. Is erected on the positioning substrate 340 via the jig 341. At this time, the positioning substrate 410 on which the AE sensor 400 is mounted as described above is in surface contact with the positioning substrate 340 as described above.

  In such a state, as described above, when the mold 360 is displaced downward and collides with the proximal end opening 111 of the metal shell 110 at the distal end portion 362, the mold 360 is moved to the distal end portion. At the lower end. Therefore, the position sensor 460 detects the tip 362 of the mold 360 and generates a position detection signal.

  Along with this, the delay circuit 470 generates a delay signal based on the position detection signal from the position sensor 460 and inputs it to the counter 480. At such a stage, since the delay signal is at a high level (waiting period), the counter 480 is not reset-started.

  In addition, when the mold 360 collides with the proximal end opening 111 of the metal shell 110 as described above, the sensor structure 201 generates a shock wave as described above. The shock wave generated in this way propagates from the sensor structure 201 to the positioning substrate 340 via the jig 341.

  The shock wave thus propagated propagates from the positioning substrate 340 through the positioning substrate 410 to the receiving plate 433 of the AE sensor 400, as described above. Here, since both positioning substrates are in good surface contact as described above, the propagation of the shock wave from the positioning substrate 340 to the positioning substrate 410 is performed well.

  When the shock wave propagates to the receiving plate 433 as described above, the receiving plate 433 vibrates in the plate thickness direction according to the frequency of the shock wave, and the piezoelectric element 434 generates a piezoelectric voltage along with the vibration of the receiving plate 433. To the preamplifier 440 via the lead wire 435.

  Then, this preamplifier 440 amplifies the piezoelectric voltage from the piezoelectric element 434 and outputs it to the signal discrimination unit 450. Accordingly, in the signal discrimination unit 450, the predetermined low frequency component of the amplified voltage of the preamplifier 440 is removed by the HPF 451, and the remaining frequency component is output to the amplifier 452 as a filter voltage. .

  Along with this, the filter voltage is amplified by the amplifier 452, and then detected by the detector 453 and output to the signal discriminator 454 as a detection signal. Accordingly, the signal discriminator 454 compares the detection signal with the predetermined threshold value to discriminate. Here, if the signal discriminator 454 generates a discrimination signal based on the detection signal generated from the detector 453 in response to the shock wave caused by the collision with the metal shell 110 of the mold 360, the discrimination signal is output to the counter 480. The

  At this time, as described above, the counter 480 has not been reset and started (during the standby period), so the counter 480 does not count the discrimination signal.

  Thereafter, when the shock wave caused by the collision of the metal mold 360 with the metal shell 110 disappears and the delay signal from the delay circuit 470 decreases to a low level, the counter 480 is reset and started to start counting.

  In addition, even after the mold 360 collides with the metal shell 110 as described above, a downward displacement force is continuously applied to the mold 360, so that the proximal end opening 111 of the metal shell 110 is The die 360 is caulked inward at the tip 362 thereof (see the circle 113 shown in FIG. 9).

  At this time, the insulating member 121 is pressed in the radial direction by the proximal end opening 111 of the metal shell 110 due to the caulking force described above, and causes elastic strain. This elastic strain increases as the pressing force against the insulating member 121 increases. When the elastic strain reaches a strain that exceeds the elastic limit of the insulating member 121, the insulating member 121 may be broken.

  In such a process, the insulating member 121 generates a vibration wave according to an increase in elastic strain due to the caulking force. Here, the frequency of the vibration wave belongs to the specific frequency range generated due to the elastic strain of the insulating member 121.

  Further, the amplitude of the vibration wave increases as the elastic strain of the insulating member 121 due to the caulking force increases. This means that the amplitude of the vibration wave is maximized when the insulating member 121 is cracked.

  As described above, the vibration wave generated due to the caulking force propagates from the sensor structure 201 to the positioning substrate 340 via the jig 341, and further passes through the positioning substrate 410 and the AE sensor 400. Propagates well to the receiving plate 433.

  Then, the receiving plate 433 vibrates in the plate thickness direction according to the frequency of the vibration wave generated due to the caulking force as described above. With such vibration, the piezoelectric element 434 generates a piezoelectric voltage and outputs it to the preamplifier 440 via the lead wire 435. Here, the piezoelectric voltage generated from the piezoelectric element 434 is different from the piezoelectric voltage corresponding to the shock wave caused by the caulking force described above.

  Thus, the preamplifier 440 amplifies the piezoelectric voltage from the piezoelectric element 434 and outputs it to the signal discrimination unit 450. Accordingly, in the signal discrimination unit 450, the predetermined low frequency component of the amplified voltage of the preamplifier 440 is removed by the HPF 451, and the remaining frequency component is output to the amplifier 452 as a filter voltage. .

  Along with this, the filter voltage is amplified by the amplifier 452, then detected by the detector 453, and output to the signal discriminator 454 as a detection signal. Along with this, the signal discriminator 454 compares the detection signal from the detector 453 with the predetermined threshold value, discriminates, sequentially generates discrimination signals, and outputs them to the counter 480.

  At this time, as described above, the counter 480 has already been reset and started and is in a counting state (counting period). Therefore, the counter 480 counts the discrimination signals sequentially output from the signal discriminator 454.

  When the count value of the counter 480 reaches the predetermined value accompanying such counting, the counter 480 generates a count signal and outputs it to the buzzer circuit 490. For this reason, the buzzer circuit 490 sounds the buzzer. Thereby, it can be seen that the finished product 200 is a defective product due to the cracking of the insulating member 121 or the like.

  On the other hand, if the signal discriminator 454 does not generate a discrimination signal, or if the count value of the counter 480 does not reach the predetermined value even if the signal discriminator 454 generates a discrimination signal, the counter 480 does not generate a count signal. . Therefore, the buzzer of the buzzer circuit 490 does not sound. Thereby, the sensor structure 201 becomes a non-defective finished product 200 based on the heat caulking process.

  As described above, when a crack occurs in the insulating member 121 due to the thermal caulking of the metal shell 110 in the thermal caulking process, the vibration wave generated along with the crack is detected by the AE sensor 400 by the detection device. The detection output is sequentially discriminated as a discrimination signal by the signal discrimination unit 450 as described above, the discrimination signal is counted by the counter 480, and when the count value reaches the predetermined value, the buzzer circuit 490 Ring.

  Here, as described above, even if the signal discriminating unit 450 may generate a discrimination signal due to a shock wave generated by the collision with the metal shell 110 of the mold 360 as described above, the delay circuit 470 Based on the position detection signal generated from the position sensor 460 when the mold 360 is displaced to the descending end, a delay signal is generated at a high level and the reset start of the counter 480 is prohibited, so that the buzzer of the buzzer circuit 490 sounds. There is no.

  As a result, the insulating member 121 is not mistakenly cracked due to a shock wave caused by a collision with the metallic shell 110 of the mold 360. Therefore, based on the ringing of the buzzer 490 in the heat caulking process, it can be correctly recognized that the insulating member 121 has cracked due to the heat caulking of the metal shell 110.

  In particular, even if the insulation member 121 is not visible because the crack has occurred inside the metal shell 110, it can be correctly recognized that the insulation member 121 has cracked.

  Needless to say, the present invention is not limited to the above-described embodiment, but may take various forms as long as it belongs to the technical scope of the present invention. For example, as shown in FIG. 11, a recording apparatus 500 for recording a discrimination signal (vibration wave discrimination signal) output from the signal discrimination unit 450 can be provided. The recording device 500 is configured to receive the count signal generated by the counter 480. In addition, the recording apparatus 500 includes a primary storage unit that temporarily stores the discrimination signal output from the signal discrimination unit 450 for each counting period, and the primary storage when the count signal from the counter 480 is input to the recording apparatus 500. A signal storage unit that stores the discrimination signal stored in the unit. That is, the recording apparatus 500 is configured to be able to record only the discrimination signal waveform when the counter 480 outputs a count signal (in other words, when a crack occurs in the insulating member 121).

  By providing such a recording apparatus 500, the discrimination signal waveform stored in the signal storage unit can be analyzed in detail. Specifically, by analyzing at which timing in the counting period a waveform having a large amplitude among the discrimination signal waveforms is generated, it is possible to specify the crack occurrence position of the insulating member 121. Further, by analyzing the continuity of the waveform having a large amplitude, it becomes possible to accurately distinguish whether the insulating member 121 is cracked or whether the counter 480 erroneously generates a count signal due to noise. Further, since the recording apparatus 500 is configured to record only the discrimination signal waveform when the counter 480 outputs the count signal, the data capacity recorded in the recording apparatus 500 can be reduced, and the recording apparatus 500 can be reduced. Can be constructed with a simple system.

  Further, in carrying out the present invention, the positioning substrates 340 are arranged in a line to constitute a belt conveyor, and the detection device is arranged for each of the talc pressing process and the heat caulking process, thereby automatically manufacturing the gas sensor. You may make it test | inspect automatically.

  In implementing the present invention, not only the buzzer circuit 490 but also various notification means such as a lamp and a display device may be used for notification based on the count output of the counter 480.

  In implementing the present invention, not only the hydraulic device 300 but also, for example, a pneumatic device may be employed, or a linear reciprocating mechanism such as a linear actuator or other mechanism for applying a load may be employed. Good.

  In implementing the present invention, the present invention is not limited to detection of cracks in the insulating member 121, and may be applied to detection of cracks in the plate sensor element unit 122, for example.

  In implementing the present invention, the gas sensor is not limited to the above-described gas sensor, and a cylindrical or plate-shaped sensor element is arranged in a cylindrical metal shell, and is arranged between the metal shell and the sensor element. You may apply to the manufacturing process of the gas sensor which fixed the sensor element to the metal fitting by pressurizing and filling the inorganic powder etc. which were carried out.

  In implementing the present invention, the delay circuit 470 generates a high-level or low-level delay signal based on the position detection signal from the position sensor 460. However, the delay circuit 470 is not limited to this. A delay signal may be generated based on a switching signal generated by a switching operation of the switching valve 350 of the device 300.

  In implementing the present invention, the present invention is not limited to a gas sensor, and may be applied to, for example, a spark plug. Here, the spark plug is a cylindrical metal shell, an insulator fitted into the metal shell so that the tip protrudes, and a center provided inside the insulator with the tip protruding. An electrode and a ground electrode, one end of which is coupled to the metal shell, and the other end is disposed to face the tip of the center electrode. Among these, the front side between the inner surface of the rear opening opposite to the front side to which the ground electrode is coupled in the metal shell and the flange-shaped protrusion formed at the axial intermediate portion of the insulator A ring-shaped packing, a packing layer such as talc, and a ring-shaped packing are arranged in order, and the metal shell and the insulator are fixed by caulking the rear opening edge of the metal shell inward.

  By the way, in the step of caulking and fixing the metal shell and the insulator in the spark plug as described above, the insulator may be cracked. Therefore, by applying the present invention to the spark plug manufacturing process, it can be correctly recognized that a crack has occurred in the insulator.

It is a block diagram showing one embodiment of an inspection device concerning the present invention. It is a side view which shows the sensor main body before a talc pressing process. It is an exploded view of the sensor main body of FIG. It is a side view which shows the sensor structure before a heat crimping process. FIG. 5 is an exploded view of the sensor structure of FIG. 4. It is a schematic structure side view for performing the test | inspection by an test | inspection apparatus according to the process of the talc pressing process with respect to the sensor main body of FIG. It is an enlarged plan view which shows the arrangement | positioning state of both the positioning boards of FIG. It is a schematic structure side view for performing the test | inspection by a test | inspection apparatus according to the process of the heat crimping process with respect to the sensor structure of FIG. It is an enlarged side view which shows the finished product which is a sensor structure after a heat crimping process. It is an expanded sectional view of the AE sensor of FIG. It is a block diagram which shows embodiment of the test | inspection apparatus provided with the recording device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Sensor main body, 121 ... Insulating member, 201 ... Sensor structure,
340, 410 ... Positioning substrate, 400 ... AE sensor, 450 ... Signal discrimination unit, 460 ... Position sensor, 470 ... Delay circuit, 480 ... Counter, 490 ... Buzzer circuit, 500 ... Recording device.

Claims (10)

In one of the steps of manufacturing the structure in which the ceramic member is fixed inside the housing, when a load is applied to the structure by a load applying unit so that a load is applied to the ceramic member, Detecting the vibration wave generated from the structure as a vibration wave signal,
Of the vibration wave signals, the vibration wave signals detected within a predetermined counting period after a predetermined waiting period has elapsed since the load applying means has reached a predetermined position,
A structure inspection method, wherein the presence or absence of damage to the ceramic member is inspected based on a count value of the vibration wave signal. The vibration wave signal is compared with a predetermined threshold, and the vibration wave signal equal to or higher than the threshold is discriminated as a vibration wave discrimination signal,
Counting the vibration wave discrimination signal detected within the counting period of the vibration wave discrimination signal,
2. The structure inspection method according to claim 1, wherein the inspection of whether or not the ceramic member is damaged is performed based on whether or not a count value of the vibration wave discrimination signal has reached a predetermined value. In the structure, the housing is disposed so as to surround the ceramic member, and the housing and the ceramic member are fixed by compressing and filling inorganic powder between the housing and the ceramic member. Yes,
3. The method according to claim 1, wherein one step of the manufacturing process is a step of compressing the inorganic powder filled between the housing and the ceramic member by the load applying unit. Inspection method of structure of description. The structure inspection method according to claim 3, wherein the ceramic member has a cylindrical shape or a plate shape. The said structure is a gas sensor, The structure inspection method of any one of Claims 1-4 characterized by the above-mentioned. In one of the steps of manufacturing the structure in which the ceramic member is fixed inside the housing, when a load is applied to the structure by a load applying unit so that a load is applied to the ceramic member, A vibration wave signal detecting means for detecting a vibration wave generated from the structure as a vibration wave signal;
Position detecting means for detecting a position of the load applying means and generating a position detection signal;
A delay signal generating means for generating a delay signal for a predetermined time when the position detection signal reaches a predetermined value;
Counting means for counting vibration wave signals detected within a predetermined counting period after the generation period of the delay signal among the vibration wave signals;
An inspection device for a structure comprising: an informing means for informing that when the ceramic member is damaged in accordance with a count value of the counting means. A discriminating means for comparing the vibration wave signal with a predetermined threshold and discriminating the vibration wave signal equal to or higher than the threshold as a vibration wave discrimination signal;
The counting means counts vibration wave discrimination signals detected within the counting period among the vibration wave discrimination signals discriminated by the discrimination means,
The structure inspection apparatus according to claim 6, wherein the notification unit notifies when the count value of the vibration wave discrimination signal counted by the counting unit reaches a predetermined value. . In the structure, the housing is disposed so as to surround the ceramic member, and the housing and the ceramic member are fixed by compressing and filling inorganic powder between the housing and the ceramic member. Yes,
8. The method according to claim 6, wherein one step of the manufacturing process is a step of compressing the inorganic powder filled between the housing and the ceramic member by the load applying unit. Inspection apparatus for the described structure. 9. The structure inspection apparatus according to claim 8, wherein the ceramic member has a cylindrical shape or a plate shape. The structure inspection apparatus according to any one of claims 6 to 9, wherein the structure is a gas sensor.