AE sensor mounting structure

Abstract

For each of the AE wave sources within the same propagation range, the location and waveform characteristics can be obtained without interference. [Solution] The AE sensor mounting structure of the present invention is located in a processing apparatus 1 in which a plurality of independent processing parts 2 are arranged adjacent to each other, and AE waves generated in each of these processing parts 2 propagate toward each other in the direction in which each processing part 2 is located. Each AE sensor S is placed on an individual member constituting each processing part 2 in the direction in which the processing force is applied to each processing location (each molding part P) of each processing part 2. [Effect] Even though multiple AE waves propagate intertwined within the AE propagation range from adjacent processing parts, it is possible to individually detect which processing part generated which AE wave and what its waveform is.

Description

Technical Field

[0002] , ,

[0005] ,

[0004] , , , , ,

[0003]

[0001] The present invention relates to an AE sensor mounting structure capable of obtaining position identification and waveform characteristics without being interfered by each AE wave of a plurality of AE wave generation sources within the same propagation range.

Background Art

[0002] An acoustic emission sensor (hereinafter referred to as "AE sensor") detects elastic energy stored inside as sound waves (elastic waves, AE waves) in a frequency band of several tens of kHz to several MHz, which are emitted when the inspection target material is deformed or destroyed.

[0003] AE waves generated by small scratches or slight friction propagate like ripples (radially). Therefore, the installation position of the AE sensor is not severely restricted. If a plurality of AE sensors are provided in the range to be detected, the position of the AE wave generation source can be detected under the propagation condition of the AE wave, and if the waveform characteristics of the AE wave under normal conditions (without abnormality) can be grasped, various structural abnormalities and their occurrence positions can be detected early.

[0004] Furthermore, as described above, the AE sensor can detect the generation even at a position away from the AE wave generation source, and can detect the generation source, normal or abnormal conditions by using a plurality of sensors. Therefore, it can be installed at any position within the propagation range of the AE wave. For example, in an "existing" processing machine or processing device, the AE sensor can be installed in the vicinity of a processing position that does not interfere with the processing operation, such as in the propagation range of the AE wave, where the signal can be easily extracted (wiring is easy), and the installation and removal are easy.

[0005] Patent Document 1 (Japanese Patent Publication No. 2008-180558) discloses an AE sensor installed on the die of a forging machine, which is used to accurately detect the damage status of molds, etc., while suppressing the effects of amplitude vibrations and noise caused by the operation of the processing equipment, etc., by running the forging equipment in a dry-forging operation to detect the AE detection signal, setting an effective range for extracting AE from the AE detection signal detected during processing based on the detected AE detection signal, extracting an amplitude signal within the set effective range from the AE detection signal when forging a workpiece, and calculating the fractal dimension m of AE based on the extracted amplitude signal to determine the life of the die.

[0006] Furthermore, for example, Patent Document 2 (Japanese Patent Application Publication No. 2019-158899) discloses a method for easily detecting cracks occurring in a structure, comprising a first sensor group, a second sensor group, and a localization unit, wherein the first sensor group includes a plurality of AE sensors arranged spaced apart from each other in the direction in which the weld extends and attached to a second member which is a trough rib, the second sensor group includes a plurality of AE sensors attached to the first member, and the localization unit handles the detection results of the plurality of AE sensors included in the first sensor group and the detection results of the plurality of AE sensors included in the second sensor group separately, and performs localization of the source position of elastic waves based on the detection results of the first sensor group and localization of the source position of elastic waves based on the detection results of the second sensor group separately.

[0007] As mentioned above, Patent Document 1 can obtain AE waves caused by damage to a target structure from detection signals resulting from the operation of a processing device, and Patent Document 2 can identify the occurrence and location of cracks in a target structure. However, with conventional AE sensor mounting structures, the following problems arise when multiple AE wave sources exist within the propagation range of the AE waves.

[0008] In conventional AE sensor mounting structures, if there are multiple AE wave sources within the propagation range of an AE wave, it would theoretically be possible to determine their "location" by comparing the arrival times of the AE waves at each of the multiple AE sensors. However, this would require measurement technology capable of measuring time with microsecond precision and analysis technology to process that data, which would necessitate extremely specialized technology separate from the AE sensor mounting structure itself, making it far from easily achievable. Furthermore, from the perspective of time measurement accuracy and analysis reliability, the accuracy of locating the AE wave sources was not high due to noise, errors, differences in AE wave waveform characteristics, and the mixing (interference) of AE waves within the same propagation range.

[0009] As described above, with conventional AE sensor mounting structures, it is difficult to identify the source of an AE wave when there are multiple sources of AE waves within the propagation range. Furthermore, when multiple sources of AE waves are located close together within the propagation range and generate AE waves from them almost simultaneously, it becomes virtually impossible to determine the location of the AE wave source or the characteristics of the generated AE wave using the conventional method described above, which relies on the difference in arrival times of the AE waves. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2008-180558 [Patent Document 2] Japanese Patent Publication No. 2019-158899 [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] The problem that this invention aims to solve is the difficulty in determining the location and obtaining the waveform characteristics of each of the AE waves from multiple AE wave sources located within the same propagation range. [Means for solving the problem]

[0012] The present invention, which solves the above problems, Individual components Multiple independent processing units This processing section is constructed and connected via a common component. In a machining apparatus where AE waves are arranged adjacent to each other and propagate mutually in the direction of each machining section, AE sensors for identifying the source of the AE waves and obtaining their AE wave characteristics are placed on individual components constituting each machining section in the direction in which the force for machining is applied, flanking each machining area. [Effects of the Invention]

[0013] According to the AE sensor mounting structure of the present invention, even though multiple AE waves propagate intertwined within the AE propagation range from adjacent processing parts, it is possible to individually detect which processing part generated which AE wave and what waveform it has. [Brief explanation of the drawing]

[0014] [Figure 1] This is a perspective view showing the processing apparatus that forms the basis of the present invention. [Figure 2] This is a cross-sectional view showing the processing apparatus, which is the prerequisite configuration of the present invention, with an AE sensor installed. [Figure 3] Figures (a), (b), and (c) show the waveform of the AE wave detected by the AE sensor in the AE sensor mounting structure of the present invention, respectively. [Figure 4] (a) and (b) are figures showing the waveform of the AE wave detected by the AE sensor mounting structure, respectively, for comparison. [Modes for carrying out the invention]

[0015] For example, similar to installing measurement values at various locations in Japan to observe the epicenters and characteristics of earthquakes, AE sensors have the property that "they can be attached anywhere (conveniently) as long as it is within the AE wave propagation range." In view of this property, in a processing apparatus having a processing part that is the AE wave generation source, if at least two AE sensors are provided within the AE wave propagation range, the AE wave generation source should be able to be specified.

[0016] Based on the above characteristics of AE sensors, conventionally, in a processing apparatus with a structure where a plurality of mutually independent processing parts are arranged adjacent to each other and the AE waves generated by these processing parts propagate mutually in the directions where each processing part exists, within the AE wave propagation range, it was attached to a member shared by the entire configuration, such as a case (housing), on a surface where wiring, attachment, and removal are easy and the appearance is convenient to view.

[0017] However, in the conventional attachment, each AE wave that occurred almost simultaneously in a plurality of adjacent processing parts within the AE wave propagation range became mixed, and although the occurrence of the AE wave itself could be detected, it was impossible to determine which processing part was the generation source and what waveform it was for the AE wave detected by each AE sensor due to interference.

[0018] In a processing apparatus where a plurality of processing parts are adjacent to each other, that is, exist in the vicinity, within the same AE wave propagation range, and the AE waves occur almost simultaneously, it was thought that the merits of AE sensors could not be fully enjoyed and the above situation could not be improved. However, as a result of intensive research, it was found that there is a correlation between the force transmission characteristics involved in processing in the processing part and the AE wave propagation characteristics.

[0019] For example, when receiving the pressing force from above, the pressing load (excluding the reaction force here) is transmitted to the lower member, and the pressing load does not act on the other adjacent processed part in the actually contacting state. However, the AE wave propagates to the other adjacent processed part in the contacting state. Since the transmission of force is accompanied by the AE wave which is an impact wave, in the AE wave propagation range, if a plurality of AE sensors are provided on a member shared by a plurality of processed parts across the plurality of processed parts, the AE waves will interfere with each other. However, by providing an AE sensor on each individual member constituting each processed part for each adjacent processed part in the actually contacting state, although the AE waves generated for each processed part propagate in a jumbled manner with each other, the interference is limited in the AE sensor and does not prevent the identification of the position and the grasping of the waveform of the AE wave.

[0020] That is, when a plurality of AE sensors are provided in the AE wave propagation range where a plurality of processed parts are arranged adjacent to each other and the AE waves generated in these processed parts propagate mutually in the direction where the other processed parts exist, if the AE wave propagation range is not physically constituted by sharing one member, and an AE sensor is provided for each processed part on an independent member for each processed part (with the same conditions and materials), that is, a physically individual member for each processed part, the source of the AE wave in a plurality of processed parts and the waveform characteristics of the AE wave can be clearly obtained for each processed part.

[0021] Therefore, by adopting the AE sensor mounting structure of the present invention, even if a plurality of AE waves are generated simultaneously, for example, from adjacent processed parts, although they propagate in a jumbled manner within the AE propagation range, there is almost no influence of interference or synthesis, and it is possible to individually detect which processed part the AE wave is generated from and what waveform the AE wave has. Therefore, an appropriate number of AE sensors can be provided at appropriate locations, and the prediction of device abnormalities based on the collection of AE waves by the AE sensors can be performed with higher accuracy than before.

Example

[0022] Embodiments of the present invention will be described with reference to the drawings. Hereinafter, the AE mounting structure of the present invention will be described using a die device in a press machine with the following configuration as an example of the processing machine 1. The present invention is not unique in the configuration of the processing machine 1 itself, in which a plurality of independent processing parts 2A, 2B, and 2C (collectively referred to as processing part 2) are arranged adjacent to each other in this example, and the AE waves generated in each of these processing parts 2 propagate toward each other in the direction of each processing part 2. Any other processing machine with the above configuration may be used, but the mounting structure of the AE sensors SA, SB, and SC (collectively referred to as AE sensors S) described later is unique.

[0023] In the processing apparatus 1 shown in this example, 3 is the upper plate, 4 is the punch holder, 5 is the bolster, and 6 is the lower plate. These are components that span across each processing section 2 in this example. "Spanning across each processing section 2" means that they are not components separately provided for each processing section 2A, 2B, and 2C, but rather are shared by each processing section 2 as a single, unbroken component.

[0024] Furthermore, the configuration of the processing section 2A of the processing apparatus 1 is as follows: 7A is a pressure plate, 8A is an upper die, 9A is a punch plate, 10A is an upper punch, 11A is a pressure plate, 12A is a lower die, 13A is a punch plate, 14A is a lower punch, and PA is the forming section.

[0025] The configuration of the processing section 2B is as follows: 7B is a pressure plate, 9B is a punch plate, 10B is an upper punch, 11B is a pressure plate, 12B is a lower die, 13B is a punch plate, 14B is a lower punch, and PB is the molding section.

[0026] The configuration of the processing section 2C is as follows: 7C is a pressure plate, 9C is a punch plate, 10C is an upper punch, 11C is a pressure plate, 12C is a lower die, 13C is a punch plate, and 14C is a lower punch, and PC is the forming section.

[0027] The configuration of each processing section 2, consisting of the above-mentioned components, is as follows: the upper plate 3, punch holder 4, bolster 5, and lower plate 6 are positioned as "shared components" that span across processing sections 2A, 2B, and 2C, whereas the upper plate 3, punch holder 4, bolster 5, and lower plate 6 are positioned as "individual components" that constitute processing sections 2A, 2B, and 2C. In other words, the "individual components" that constitute processing sections 2A, 2B, and 2C are not provided across each processing section 2, are not shared, and (although they are in contact) are separated.

[0028] In the processing apparatus 1 with the above configuration, each of the multiple AE sensors S is mounted at a specific position. Conventionally, when AE sensors are mounted in the processing apparatus 1 with the above configuration, at least two sensors are provided, for example, in the processing apparatus 1 in this example, at positions where mounting and removal are easy, due to the characteristic that they can be mounted anywhere within the range where AE waves propagate.

[0029] Specific examples of the conventional AE sensor mounting positions described above are common components such as the upper plate 3, punch holder 4, bolster 5, and lower plate 6, where the sensors were installed on the outer surface perpendicular to the direction in which the processing force is applied. Figures 1 and 2 show, for example, a state in which AE sensors S1 and S2 are installed on the outer surface of the bolster 5, which is a common component, at positions between processing sections 2A and 2B and between processing sections 2B and 2C, respectively.

[0030] If AE sensors S1 and S2 are installed on a common member that spans across each processing section 2, such as the upper plate 3, punch holder 4, bolster 5, and lower plate 6, then naturally, the AE waves generated in the molding sections PA, PB, and PC (collectively referred to as each molding section P) will propagate to each AE sensor S. Therefore, it is possible to detect the AE waves themselves, but it is not possible to determine which part of the molding sections PA, PB, and PC is the source and what kind of waveform it is (see below).

[0031] Therefore, in the present invention, each AE sensor S is placed in the processing apparatus 1 on individual members constituting each processing section 2 in the direction in which the processing force is applied, sandwiching each processing location (forming section PA, PB, PC) of each processing section 2. Specifically, in this example, AE sensors SA, SB, and SC are provided on individual members in the direction in which the processing force is applied by the upper punches 10A, 10B, 10C and the lower punches 14A, 14B, 14C, sandwiching the forming sections PA, PB, PC of processing sections 2A, 2B, 2C shown in Figure 2, for example, on the lower pressure receiving plates 11A, 11B, 11C.

[0032] As long as the processing sections 2A, 2B, and 2C are in contact via a common member, the AE waves generated in each processing section 2 propagate to each AE sensor S. Therefore, even if AE sensors SA, SB, and SC are provided on each of the "individual members" of the pressure plates 11A, 11B, and 11C, the AE waves generated in the molding sections PA, PB, and PC will still propagate to each AE sensor.

[0033] However, in a processing apparatus 1 such as a press apparatus, as in the present invention, in which a plurality of independent processing parts are arranged adjacent to each other, and the AE waves generated in these processing parts propagate to each other in the direction of each processing part, if each AE sensor S is positioned in accordance with the direction in which the processing force is applied to each forming part P sandwiching each processing part 2, then only the AE waves of each forming part P corresponding to each AE sensor S are amplified, or in other words, the AE waves of each forming part P that does not correspond to each AE sensor S are attenuated as they propagate.

[0034] Here, the detection of AE waves in a situation where the AE sensor S is placed on individual members and common members will be explained along with the effects of the present invention with reference to Figures 3 and 4. Figure 3 shows the case where the structure of the present invention is adopted, that is, when AE sensors SA, SB, and SC are provided on individual members (pressure receiving plates 11A, 11B, and 11C). Figure 4 shows the case where the structure of the present invention is not adopted, that is, when AE sensors S1 and S2 are provided on a common member (upper plate 3).

[0035] As described above, in this example, the AE sensors SA, SB, and SC are installed on the pressure plates 11A, 11B, and 11C, which are individual components facing the same direction as the force applied to each processing section 2A, 2B, and 2C. The AE sensors S1 and S2 are installed on the outer surface of the upper plate 3, which is a common component, in a direction perpendicular to the vertical direction of the upper plate 3, at positions between the processing sections 2A, 2B and between the processing sections 2B and 2C, respectively.

[0036] Figures 3 and 4 show the detection status of AE waves generated in the processed sections 2A, 2B, and 2C during one stroke of the upper plate 3, with time on the horizontal axis and the height of the detected signal on the vertical axis. First, in Figures 4(a) and 4(b), which do not employ the structure of the present invention, the AE waves from AE sensors S1 and S2 appear as a nearly uniform group with no significant differences in the strength of the detected signal level. This makes it difficult to determine which waveform corresponds to which of the molding sections PA, PB, and PC. Furthermore, since the AE waves generated in the molding sections PA, PB, and PC interfere with each other to form a composite wave, it is difficult to determine whether the waveform is due to normal behavior or abnormal behavior.

[0037] On the other hand, in Figures 3(a), 3(b), and 3(c), one waveform with a clearly higher detection signal level than the others is visible in each case. In Figure 3(a), the AE sensor SA clearly detects the AE wave generated in the molding section PA; in Figure 3(b), the AE sensor SB clearly detects the AE wave generated in the molding section PB; and in Figure 3(c), the AE sensor SC clearly detects the AE wave generated in the molding section PC.

[0038] What is particularly noteworthy is that, although the individual components of the processed parts 2A, 2B, and 2C are separated from each other, they are in contact with each other via a common component, and even though AE waves still propagate between them, the structure of the present invention makes it immediately clear which AE waves are generated in each processed part 2A, 2B, and 2C. In other words, this means that even if the timing of AE wave generation is simultaneous in each processed part 2, it becomes possible to identify the location of AE wave generation as well as understand the waveform.

[0039] At first glance, the structure of the present invention might be interpreted as being able to determine the position and waveform of the AE wave of each processing part by providing an AE sensor near each of the multiple processing parts. However, even if the "nearby" of the multiple processing parts is a common member like the AE sensors S1 and S2, and is provided in a direction other than the direction in which the processing force is applied across the processing area, for example, on the upper part of the outer surface of the bolster 5 shown in the foreground in Figure 1, the above-mentioned effects of the present invention cannot be obtained.

[0040] In other words, the reason for the difference in the effects described above is that, as in the structure of the present invention, each AE sensor 2 corresponding to each processing part 2 is provided on individual members that are in contact but have separate edges, sandwiching each processing part 2 in the direction in which the force for processing is applied. [Explanation of Symbols]

[0041] 1 Processing equipment 2 Processing section 2A Processing section 2B Processing section 2C Processing Department 3 Upper Plate 4 Punch holder 5 bolster 6 Lower Plate 7A,7B,7C Pressure receiving plate 8A Upper Die 9A, 9B, 9C Punch Plates 10A, 10B, 10C Upper punch 11A,11B,11C Pressure receiving plate 12A, 12B, 12C Lower die 13A, 13B, 13C Punch Plate 14A, 14B, 14C Lower punch PA,PB,PC molding section SA, SB, SC AE sensors

Claims

[Claim 1] An AE sensor mounting structure for a processing apparatus having a structure in which a plurality of processing parts independent of each other are made up of individual members, these processing parts are arranged adjacent to each other via a common member, and AE waves generated in these processing parts propagate toward each other in the direction of each processing part, wherein an AE sensor for identifying the source of the AE wave and obtaining its AE wave characteristics is placed on the individual members constituting each processing part in the direction in which the processing force is applied across each processing location of each processing part.

Images