JP4282188B2 - Method and device for confirming impact of sand hammer device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an impact confirmation device for a sand dropping hammer device used when removing core sand remaining in a cast product.
[0002]
[Prior art]
Conventionally, the core sand remaining in the cast product is to be crushed and removed by hitting the surface of the cast product with a hammer device. This is necessary for crushing and removing the core sand of the cast product. The striking force, striking cycle, and processing time are determined empirically from the size and shape of the cast product. If the striking force is performed with a predetermined striking force at a predetermined cycle for a predetermined time, the sand removal is completed. However, since air supplied to a number of hammer mechanisms attached to the hammer device is performed by air pipes connected in series, the air consumption of adjacent hammer mechanisms increases, decreases, or pipes When the air pressure changes due to damage to the hose, the hammering force and the hammering cycle of some or all of the hammer mechanisms are reduced, and there is a problem in that the cast product has a sand removal defect. Moreover, it is difficult to detect that the hammering force and the hammering cycle of some hammer mechanisms have decreased, and the sand removal work will be carried out until a sand removal failure is found by visual inspection after the work is completed. There was a problem that defective castings occurred continuously. Furthermore, it is necessary to stop the hammer device and check the hammer mechanisms one by one in order to find a hammer mechanism with a reduced striking cycle and impact force from a large number of hammer mechanisms, which requires time for inspection and increases productivity. There was a problem of lowering. Therefore, a method of detecting an impact cycle and impact force by attaching an acceleration sensor or strain gauge to a chisel or hammer has been proposed, but the acceleration sensor and strain gauge are damaged in a short period due to the vibration of the chisel. There is a problem that an accurate impact cycle and impact force cannot be detected because the surrounding impact is detected. In addition, since the air pressure at the air supply port pulsates due to the reciprocating movement of the hammer, a method of detecting the striking cycle and the striking force by detecting the pressure has been proposed, but the movement of the hammer of the adjacent hammer mechanism is also proposed. In addition, the pressure fluctuated, and when the air piping changed, the pulsation changed and the correct pressure could not be detected. In addition, there has been a problem that it is impossible to detect a change in striking force caused by the poor sitting of the workpiece.
[0003]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a method for confirming the hitting of a sand dropping hammer device and a device thereof that can detect the hit state of a hammer mechanism with high reliability.
[0004]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention is a method for confirming the impact of a sand removal hammer device using a chisel that is guided by a chisel guide and applies a striking force to a workpiece. A magnetic circuit that forms a magnetic flux loop from the gap of the yoke to the chisel and the chisel guide is formed by attaching a yoke having a substantially C-shaped cross section in which the coil is housed and with the lower portion of the yoke facing the outer peripheral surface of the chisel. A back electromotive force is generated in the coil of the magnetic circuit by a gap generated in the abutting surface of the chisel and the chisel guide by the impact, and the impact period is detected from the back electromotive force period generated in the coil of the magnetic circuit, and a gap is formed. striking confirmation method shakeout hammer device for detecting the impact force from the counter electromotive force based on the state and the invention of claim 1, the striking force to the workpiece being guided by the chisel guide A hammer check device for a sand hammer using a chisel, wherein a yoke having a substantially C-shaped cross section in which a coil is housed is attached to the outer peripheral surface of the chisel guide, and the lower portion of the yoke is connected to the outer peripheral surface of the chisel The magnetic circuit that forms a magnetic flux loop from the gap of the yoke to the chisel and the chisel guide is formed. Sand provided with a detection unit for generating and a detection signal processing unit for detecting a striking force from a back electromotive force amount based on a gap formation state while detecting a striking cycle from a back electromotive force cycle generated in a coil of a magnetic circuit A hammer checking device for a dropping hammer device is claimed in claim 2, and the hammer of the sand dropping hammer device in which the detection portion and the detection signal processing portion are separately arranged in the invention of claim 2 The certification apparatus and the invention of claim 3, keep the invention of claim 2 or 3, the detection signal processing section, the detected striking period and striking force shakeout hammer device judging circuit is provided for comparing with a threshold The invention of claim 4 is the invention of claim 4, and in the inventions of claims 2 to 4, the invention of claim 5 is the hammer confirmation device of the sand removal hammer device in which the detection signal processing unit is centrally managed. in 5 of the invention, it is shall be a striking confirmation apparatus shakeout hammer device pressure sensor for detecting the supply air pressure is connected to the detection signal processor as defined in claim 6.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Next, a preferred embodiment of the present invention will be described in detail with reference to the drawings.
Reference numeral 1 denotes a frame-shaped frame. The frame-shaped frame 1 includes a work table 2, an upper mounting plate 4 for hanging a plurality of hammer mechanisms 3 for sand removal, a mounting table 2, and an upper mounting plate 4. And a support column 5 connecting the two. The hammer mechanism 3 attached to the upper mounting plate 4 of the frame-like frame 1 is formed at an outer cylinder 6, an inner cylinder 7 that is inserted into the outer cylinder 6 so as to be movable up and down, and a tip portion of the inner cylinder 7. A chisel 8 made of magnetic material (hardened steel) attached to a chisel guide 7a made of magnetic material (hardened steel) and a rear end surface of the chisel 8 attached to the inner cylinder 7 are repeatedly hit. It consists of a hammer 9 to do.
[0006]
Reference numeral 10 denotes detection means for detecting the striking cycle and striking force of the hammer mechanism 3, and the detection means 10 is a magnetic circuit detection unit 10a comprising a yoke 12 and a coil 14, and a detection signal separated from the detection unit 10a. It consists of the processing part 10b. The magnetic circuit of the detection unit 10a forms a magnetic flux loop toward the abutting surface 11 of the hammer mechanism 3 made of a magnetic material. When a gap is formed in the abutting surface 11, the coil 14 of the magnetic circuit is caused by electromagnetic induction. To generate back electromotive force. The detection signal processing unit 10b is an electronic circuit that detects the striking cycle and striking force of the hammer mechanism 3 from the back electromotive force cycle and the amount of back electromotive force detected by the detecting unit 10a.
[0007]
The detection unit 10a will be described in detail with reference to FIG. 2. A yoke 12 having a C-shaped cross section made of a magnetic material having a gap positioned on the abutting surface 11 of the chisel 8 and the chisel guide 7a of the hammer mechanism 3 includes a chisel. An annular upper yoke 12a mounted around the guide 7a and a lower yoke 12b disposed around the chisel 8 in combination with the annular upper yoke 12a. The coil 14 constitutes a magnetic circuit. Further, a gap of about 0.1 to 0.2 mm is provided between the lower yoke 12b and the chisel 8 so that they do not contact each other. This gap is provided so as not to obstruct the movement generated between the chisel 8 and the chisel guide 7a. When the coil 14 is energized, a magnetic flux loop from the air gap of the yoke 12 toward the chisel 8 and the chisel guide 7a is formed with the butting surface 11 sandwiched by the magnetic circuit. And if a gap is formed in the butt | matching surface 11 by a hit | damage effect | action, the path | route of magnetic flux will become long, magnetic resistance will increase slightly, and magnetic flux will reduce. Due to the decrease in the magnetic flux, an electromagnetic induction action occurs, and a counter electromotive force based on the gap formation state is generated in the coil 14. The magnitude of the peak voltage (pulse) of the back electromotive force generated in this way is proportional to the speed at which the gap is formed, and the peak voltage time (pulse width) is the time at which the gap is formed (gap size). It seems to be related to. Therefore, the striking force can be calculated from the magnitude of the peak voltage (pulse) or the magnitude of the peak voltage time (pulse width). Furthermore, when the peak voltage time (pulse width) is too large, it is possible to detect that the workpiece is not satisfactorily or that a crack has occurred.
[0008]
Further, as shown in FIG. 3, the detection signal processing unit 10b includes an amplification circuit 13 for amplifying the counter electromotive force generated in the coil 14 of the magnetic circuit of the detection unit 10a, and a peak voltage and a peak voltage from the amplified counter electromotive force. Filter circuit 14 for extracting the period of the current, A / D conversion circuit 15 for converting the extracted peak voltage and its period into a digital signal, and the striking period and peak voltage obtained from the pulse period of the detected peak voltage. A judgment circuit 16 for judging the quality of the striking state by comparing the striking force calculated from the magnitude of the pulse or the pulse width of the peak voltage time with the striking cycle and the striking force as a threshold, and a good / bad display or peak voltage And a display unit 17 for displaying the period numerical value. Next, the graph of FIG. 4 shows the relationship between the air pressure, the peak voltage, the cycle (blow cycle), and the blow force, which are the criteria for determining whether or not the hit state is good. As can be seen from this graph, when the air pressure increases, the peak voltage and impact force increase and the period decreases, and when the air pressure decreases, the peak voltage and impact force decrease and the period increases. Therefore, there is a correlation between the air pressure and the peak voltage or period, and the striking force. From this correlation, the air pressure abnormality can be predicted from the peak voltage, period, and striking force, and conversely the peak from the air pressure. Abnormalities in voltage, that is, striking force and striking cycle can be predicted. The determination circuit 16 includes a CPU 16a and a ROM 16b and a RAM 16c connected to the CPU 16a. The ROM 16b stores threshold values of peak voltage data or striking force data and striking cycle data, and the RAM 16c has a detection unit. The hitting force data calculated from the peak voltage detected by 10a or the peak voltage and the hitting cycle data are stored. Then, by comparing the data in the ROM 16b and the data in the RAM 16c by the CPU 16a, it is possible to determine whether or not the data detected by the detection unit 10a, that is, the striking cycle and the striking force are normal.
[0009]
20 is an air supply port for supplying pressure air for lowering the internal cylinder 7 to the external cylinder 6, 21 is a return spring for raising the lowered internal cylinder 7, and 22 is an internal cylinder 7 for lowering the internal cylinder 7. , 23 is an air switching mechanism for reciprocating the hammer 9, 24 is an O-ring attached to the yoke 12, and the O-ring 24 is a chisel 8. Is to prevent falling from the chisel guide 7a. 25 is a bobbin that covers the coil 14, 26 is a mounting bolt that connects the upper yoke 12a and the lower yoke 12b, 27 is a stop ring for fixing the yoke 12 to the chisel guide 7a, and 28 is a sealing material that fills the gap in the yoke 12. , 29 is a lead wire for connecting the detection unit 10a and the detection signal processing unit 10b, and 30 is a guide for a workpiece provided on the mounting table 2.
[0010]
In this configuration, first, the air supply to the pressure air supply port 20 is stopped and the internal cylinder 7 is raised by the return spring 21. As the internal cylinder 7 is raised, the chisel 8 is also moved upward and the mounting table 2 is opened, so that a cast product (workpiece) cast using the core is mounted on the mounting table 2. At this time, the workpiece is positioned in the guide 30 of the mounting table 2. Next, if the pressure air is supplied to the pressure air supply port 20, the inner cylinder 7 is lowered and the tip of the chisel 8 supported by the chisel guide 7a comes into contact with the workpiece to press the workpiece. Become. As a result, the pressure rises and the hammer 9 starts reciprocating motion.
[0011]
The reciprocating motion of the hammer 9 rises when air pressure is applied to the lower part of the hammer 9 that is in contact with the upper end of the chisel 8, and when the hammer 9 rises to a predetermined position, the air switching mechanism 23 switches the supply of air to change the hammer. Since the air pressure is applied to the upper part of 9, the hammer 9 descends and hits the upper end of the chisel 8. Then, the air pressure is applied to the hammer 9 on the chisel 8 and the hammer 9 is raised again. When the hammer 9 is lowered by this reciprocating motion, the hammer 9 strikes the upper end of the chisel 8 violently and applies an impact to the chisel 8. This impact is transmitted to the workpiece that is in contact with the chisel 8, and the core sand of the workpiece is crushed, and the crushed sand is discharged from a side hole (not shown).
[0012]
Further, when the chisel 8 is hit with the hammer 9, a gap is momentarily formed on the abutting surface 11 between the chisel 8 made of a magnetic material and the chisel guide 7a. When a gap is formed in the abutting surface 11 of the chisel 8 and the chisel guide 7a, the magnetic flux path of the magnetic circuit formed between the abutting surface 11 of the chisel 8 and the chisel guide 7a becomes long, and the magnetic resistance is It increases slightly and the magnetic flux decreases. Since this occurs instantaneously, a counter electromotive force is generated in the coil 14 of the detection unit 10a in a direction to suppress a change in magnetic flux. The back electromotive force is input to the amplification circuit 13 of the detection signal processing unit 10b via the lead wire 29 and amplified. The amplified back electromotive force is input to the filter circuit 14 to extract the peak voltage and its periodic pattern, and the extracted peak voltage and its period are converted into digital data by the A / D conversion circuit 15.
[0013]
The magnitude of the peak voltage (pulse) extracted at this time is proportional to the gap formation state, that is, the speed of magnetic flux change, and the peak voltage time (pulse width) is related to the time during which the gap is formed, that is, the gap distance. Therefore, the striking force is calculated from the magnitude or pulse width of the pulse input to the CPU 16a of the determination circuit 16, and the striking period is calculated from the pulse period. The calculated striking force and striking cycle are input to the CPU 16a of the determination circuit 16 and written to the RAM 16b, and compared with the striking force and striking cycle as a reference written in the ROM 16c of the CPU 16a, and the reference value is detected. If the batting force based on the value and the batting cycle are within the threshold, it is determined that the batting was performed with the normal batting force and the batting cycle, and if the detected value exceeds or does not satisfy the threshold, the normal batting is not performed. The display unit 17 performs OK display or NG display, or displays the detected peak voltage and its period (frequency). If normal striking force or striking cycle cannot be obtained, the apparatus is stopped to stop the casting product (workpiece) from being sent out, and the abnormal hammer mechanism 3 may be inspected and repaired. In this way, it is possible to reliably prevent generation of a cast product having a falling sand. Further, depending on the degree of abnormality, the apparatus may be stopped and inspection may be performed after the impact time is extended and sand removal of the workpiece is completed without stopping the apparatus.
[0014]
In the preferred embodiment, each detection signal processing unit 10b is attached to the hammer mechanism 3. However, if each detection signal processing unit 10b is attached to a separate control panel or the like and centrally managed, Whether or not the hammer mechanism 3 has become abnormal can be confirmed instantaneously with a small number of maintenance personnel. In this case, it is necessary to display the identification number of the hammer mechanism 3 on the display unit 17 so that it can be identified which hammer mechanism 3 is abnormal. In the preferred embodiment, the supply air pressure is not detected, but the supply air pressure is detected by the pressure sensor, and the detection data is input to the detection signal processing unit 10b. It is possible to grasp the sandfall situation more accurately by the cycle and the fluctuation of the supply air pressure. If the striking state can be confirmed accurately in this way, the CPU 16a of the determination circuit 16 calculates the striking force and the shortage of the striking cycle to extend or shorten the striking time. Can be prevented from occurring.
[0015]
【The invention's effect】
As is apparent from the above description, the present invention forms a magnetic flux on the abutting surface of the magnetic body part, and strikes the hammer mechanism from the counter electromotive force period and the amount of counter electromotive force based on the formation state of the gap generated on the abutting surface. The impact force can be detected with certainty, and the fact that the air pressure has fallen due to increased air consumption by the nearby hammer mechanism or damage to the air piping, etc., can be instantaneously determined from the decrease in impact force or the increase in impact cycle. Since it is possible to detect the hammering mechanism abnormalities reliably, it is possible to reliably prevent the casting from dropping sand, and the back electromotive force based on the gap formation state, that is, the pulse width of the peak voltage time is too large. When this is detected, it is possible to detect that the cast product is poorly seated or cracked. In addition, since the structure of the detection unit attached to the hammer mechanism is simple, it can be used for a long time without being damaged by a severe impact. Further, by attaching the detection portion to the abutting surfaces of the chisel and the chisel guide, it can be attached to a conventional hammer device, so that it is possible to perform sand removal without making a new capital investment. Further, as described in claim 3, by separating the detection unit and the detection signal processing unit and separating the detection signal processing unit from the hammer mechanism, it is possible to reliably prevent damage to an electronic circuit that is vulnerable to impact, The reliability of detection can be increased. As in claim 4, by those in which a judgment circuit for comparing a reference value blow period and the striking force to the detection signal processing section, can immediately detect the hammer device with abnormalities, the shakeout failure Can be prevented more reliably. As in claim 5, by which shall be centralized detection signal processing unit, it is possible to find instantly what abnormality from a number of hammer mechanisms, never generate a shakeout defective. In addition, since the striking state can be grasped more accurately by connecting the pressure sensor for detecting the supply air pressure to the detection signal processing section as in claim 6 , the hammering mechanism can be extended or shortened to reduce the hammering mechanism. The present invention has various advantages such as being able to prevent sand dropping from occurring even when there is an abnormality.
Therefore, the present invention greatly contributes to the development of the industry as a method for confirming hitting of a sand dropping hammer device that has solved the conventional problems.
[Brief description of the drawings]
FIG. 1 is a partially cutaway front view showing a preferred embodiment of the present invention.
FIG. 2 is a partially cutaway front view showing a main part of a preferred embodiment of the present invention.
FIG. 3 is a block diagram showing detection means according to a preferred embodiment of the present invention.
FIG. 4 is a graph showing the relationship between supply air pressure and pulse voltage period or pulse voltage in the present invention.
[Explanation of symbols]
3 Hammer mechanism 7 Chisel guide 8 Chisel
10a Detector
10b Detection signal processor
11 Butting surface
12 York
14 coils
16 Judgment circuit

Claims (6)

A method for confirming the impact of a sand removal hammer device using a chisel that is guided by a chisel guide and applies a striking force to a workpiece, and has a substantially C-shaped cross section in which a coil is housed on the outer peripheral surface of the chisel guide. A yoke is attached, and the lower part of the yoke faces the outer peripheral surface of the chisel to form a magnetic circuit that forms a magnetic flux loop from the gap of the yoke to the chisel and the chisel guide. Due to the generated gap , a counter electromotive force is generated in the coil of the magnetic circuit, the striking period is detected from the counter electromotive force period generated in the coil of the magnetic circuit, and the striking force is calculated from the amount of counter electromotive force based on the formation state of the gap. A method for confirming a hit of a sand removal hammer device, characterized by detecting. An impact confirmation device for a sand removal hammer device using a chisel that is guided by a chisel guide and applies a striking force to a workpiece, and has a substantially C-shaped cross section in which a coil is housed on the outer peripheral surface of the chisel guide. A yoke is attached, and the lower part of the yoke faces the outer peripheral surface of the chisel to form a magnetic circuit that forms a magnetic flux loop from the gap of the yoke to the chisel and the chisel guide. The detection unit that generates a counter electromotive force in the coil of the magnetic circuit by the gap that is generated, and the striking period are detected from the counter electromotive force cycle that is generated in the coil of the magnetic circuit, and the striking is performed from the amount of the counter electromotive force based on the gap formation state. A hitting confirmation device for a sand dropping hammer device, characterized in that a detection signal processing unit for detecting force is provided.   The hammer check device for a sand drop hammer device according to claim 2, wherein the detection unit and the detection signal processing unit are separately disposed. 4. The hit confirmation device for a sand removal hammer device according to claim 2, wherein the detection signal processing unit is provided with a determination circuit for comparing the detected hitting period and hitting force with a threshold value . The hammer check device for a sand hammer device according to any one of claims 2 to 4 , wherein the detection signal processing unit is centrally managed . 6. The impact check device for a sand removal hammer device according to claim 2, wherein a pressure sensor for detecting a supply air pressure is connected to the detection signal processing unit .

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