JP2007187566A - Method and device for detecting missing magnetic metal member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely detect a missing magnetic metal component with a simple structure without adding an electronic circuit. <P>SOLUTION: In a method of detecting the missing magnetic metal member, a permanent magnet 5 arranged separately at a fixed distance from an inspection object 10 is attracted by the magnetic metal member 11 of the inspection object 10 not floating by an attracting force of the permanent magnet 5, and a force attracting the permanent magnet 5 is transmitted to a load cell 3, to thereby detect omission of the magnetic metal member 11. A device for detecting the missing magnetic metal member comprises the permanent magnet 5 arranged separately at the fixed distance from the inspection object 10 not floating by the attracting force of the permanent magnet 5, and the load cell 3 for detecting directly a force applied to the permanent magnet 5 by being attracted by the magnetic metal member 11 of the inspection object 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic metal member missing detection method and apparatus for inspecting whether a magnetic metal member is attached to a predetermined position of a molded product.

  Conventionally, the absence of insert members such as nuts and bolts made of magnetic metal to be inserted into plastic moldings, or cylinder liners made of magnetic metal to be integrally inserted into an engine block made of aluminum, has been confirmed by visual inspection or cylinder liner. In general, a proximity switch is inserted and arranged inside. However, there are problems that it is difficult to eliminate inspection mistakes by visual inspection, and that labor saving cannot be promoted. Further, in the inspection using the proximity switch, it is necessary to stop the transferred engine block for each inspection, which causes a problem that the speed of the production line is lowered. Moreover, there exists a thing which detects magnetic metal parts, such as a broken needle and a waiting needle mixed in various textiles, with a permanent magnet (for example, refer patent document 2). Further, there is one that detects a minute displacement with a permanent magnet and a giant magnetostrictive element (for example, see Patent Document 3). Moreover, there exists a thing provided with the magnet and the magnetic sensor as a magnetic body detection apparatus (for example, refer patent document 1).

However, the detection signal generated in the first and second detection coils in Patent Document 2 that detects a magnetic metal part from a voltage generated by a magnetic metal member interlinked with a DC magnetic flux in a DC magnetic field of a permanent magnet is Since it is weak, it is necessary to add a new electronic circuit, and there is a problem that the apparatus becomes complicated and expensive. Moreover, since the thing of patent document 3 detects a magnetic force with a giant magnetostrictive element, the electronic circuit was required similarly to the above, and there existed a problem that an apparatus became complicated and expensive. Patent Document 1 also has a problem that the CPU is determined based on the detection result of the magnetic sensor, and the apparatus becomes expensive.
JP-A-8-304007 JP-A-10-90431 JP-A-2005-43239

  The problem to be solved is to provide a magnetic metal member missing detection method and apparatus capable of reliably detecting magnetic metal parts with a simple structure without adding an electronic circuit. is there.

  According to the present invention, a magnetic metal member of an object to be inspected that does not float due to an attracting force of the permanent magnet attracts a permanent magnet that is arranged at a certain distance from the object to be inspected, and the force by which the permanent magnet is attracted The magnetic metal member missing detection method for detecting the magnetic metal member missing by transmitting the load to the load cell is defined as the invention according to claim 1, and is separated from the object to be inspected by a permanent magnet by a suction force. The invention of claim 2 is a magnetic metal member missing detection device comprising a permanent magnet to be arranged and a load meter that directly detects a force applied to the permanent magnet by being attracted to the magnetic metal member of the object to be inspected. According to a second aspect of the present invention, there is provided the magnetic metal member missing detection device according to the third aspect, wherein the permanent magnet and the object to be inspected are relatively moved to perform scanning. Permanent magnet with cylindrical magnet According to a fourth aspect of the present invention, there is provided a magnetic metal member missing detection device that faces the outer diameter position of the metal member and that is disposed so as to be orthogonal to the scanning direction. According to a fifth aspect of the present invention, there is provided a device for detecting a missing magnetic metal member.

  According to the present invention, a magnetic metal member of an object to be inspected that does not float due to an attracting force of the permanent magnet attracts a permanent magnet that is arranged at a certain distance from the object to be inspected, and the force by which the permanent magnet is attracted Since the attractive force applied to the permanent magnet is directly applied to the load meter, the load meter directly detects the attractive force to the permanent magnet. The structure is simpler than that of a conventional device for detecting magnetic force, and a magnetic metal member can be detected with high accuracy without adding a new electronic circuit. In addition, since a drive mechanism is not required, failure is unlikely to occur, and since detection is performed without contact, wear and damage are unlikely to occur and long-term durability can be achieved.

  In addition, as described in claim 3, by performing the scanning by relatively moving the permanent magnet and the inspection object, it is possible to inspect the inspection object having a large area with the minimum number of permanent magnets. Become. Further, if the inspection object is movable with the permanent magnet fixed, the inspection object conveyed from the production line or the like can be inspected.

  According to the fourth aspect of the present invention, the two permanent magnets are opposed to the outer diameter position of the cylindrical magnetic metal member and are arranged so as to be orthogonal to the scanning direction. The attractive force to the member can be further increased, and the cylindrical magnetic metal member can be reliably detected to improve the detection accuracy.

  By changing the polarity of the permanent magnet as in the fifth aspect, the magnetic flux becomes a loop, and the attracting force of the permanent magnet becomes strong, and the detection accuracy can be improved.

Next, a preferred embodiment of the present invention will be described in detail based on an apparatus for detecting a missing cylinder liner made of a magnetic metal member inserted into an aluminum die cast engine block shown in FIGS.
In FIG. 1, reference numeral 1 denotes an inspection device. The inspection device 1 has a load meter 3 attached to the base 2, and a bearing attached to the base 2 with the force point of the load meter 3 being in contact with the lower surface. It consists of a bracket 4 pivotally attached by a pivot and a pair of left and right permanent magnets 5 attached to the tip of the bracket 4. When the permanent magnet 5 is attracted by the magnetic metal member 11, the attracting force depends on the attraction force. The bracket 4 pivots downward, and the downward pivoting force applied to the bracket 4 is directly detected by the load meter 3 that receives the lower surface of the bracket 4. In addition, the permanent magnet 5 is spaced apart from the object to be inspected 10 by a certain distance, is opposed to the outer diameter position of the cylindrical magnetic metal member 11, and is disposed so as to be orthogonal to the scanning direction. Further, the two permanent magnets 5 facing each other have opposite polarities so that the magnetic flux is formed in a loop through the magnetic metal member 11. Thus, by making the magnetic flux into a loop shape, the attractive force of the permanent magnet 5 is increased, and the detection accuracy of the magnetic metal member 11 can be increased. Reference numeral 6 denotes a spring that absorbs vibration generated in the bracket 4. The vibration is absorbed by the spring 6 to prevent a decrease in detection accuracy. However, when the inspection apparatus 1 is arranged facing upward, the bracket 6 Needless to say, a spring 6 that suspends 4 so as not to hang down due to gravity is essential. Further, the bracket 4 whose base end is pivotally attached to the base 2 can be changed in detection accuracy by adjusting the position of the load meter 3 arranged on the lower surface of the bracket 4.

Since the object to be inspected 10 has a weight of 60 to 80 kg as an aluminum engine block, the permanent magnet 5 attached to the bracket 4 is attracted without being floated by the attractive force of the permanent magnet 5. Yes. Further, the engine block is inspected while being conveyed to the next process by a conveyor or the like, and the missing of the cylinder liner as the magnetic metal member 11 is detected. The cylinder liner as the magnetic metal member 11 is inserted into an aluminum engine block as shown in FIG. In order to detect such a missing cylinder liner, two permanent magnets 5 are arranged opposite to each other on the outer diameter of the cylinder liner as shown in FIG. As a result, it is possible to more reliably determine whether or not the cylinder liner is missing, but it is needless to say that only one cylinder liner may be arranged at the outer diameter position.

  As a result of experimenting static characteristics using an engine block in which the cylinder liner of the second cylinder is missing as shown in FIG. 3, data as shown in FIG. 5 is obtained, and the measured load at the second cylinder position is zero. Therefore, it was confirmed that the missing cylinder liner of the second cylinder can be detected. The numbers 1 to 4 entered in the cylinder bores in FIG. 3 indicate cylinder numbers. Further, the numbers 1 to 4 in the round frame shown in the graph of FIG. 5 indicate the cylinder positions.

  From these experiments, it is determined whether the magnetic metal member 11 is missing or not when the peak output voltage from the load cell 3 is output for the number of cylinders of the engine, and when the output voltage is ½ of the peak. NG when there is no peak between the measurement start point and the distance at which the first cylinder is disposed, or when there is no peak between the measurement end point and the distance at which the last cylinder is disposed. The knowledge that it is possible to take the NG method is obtained.

  When the engine block as the object to be inspected 10 formed by aluminum die casting and inserted with the cylinder liner as the magnetic metal member 11 is transported to the next process, the structure configured as described above is shown in FIGS. As described above, when the inspection apparatus 1 passes under the pair of left and right permanent magnets 5, the cylinder liner made of the magnetic metal member 11 is attracted by the pair of left and right permanent magnets 5.

  Since the engine block as the object to be inspected 10 is heavy and does not float due to the attractive force of the permanent magnet 5, the permanent magnet 5 tends to be attracted to the magnetic metal member 11. This suction force is directly transmitted to the load cell 3 via the bracket 4. The load meter 3 outputs a voltage as shown in FIG. 4 according to the pressing force of the bracket 4 applied to the load meter 3. In FIG. 4, the time for scanning the entire length of the engine block is about 1.5 seconds, but it goes without saying that this scanning time is determined by the conveying speed of the conveyor.

  Since there are four cylinder liners in the four-cylinder engine, the peak of the voltage output from the load cell 3 is four places, and it can be determined that four cylinder liners are inserted. If the cylinder liner is missing, as shown in FIG. 5 (load is displayed), the number of peaks is less than four, so that it is possible to determine the missing cylinder liner.

  In the preferred embodiment, the object to be inspected 10 is an engine block and has a weight that does not float due to the attractive force of the permanent magnet 5. Needless to say, in the case of a thing that floats by the suction force, the device under test 10 is locked to a fixed object or the like so as not to float.

It is a partially cutaway front view showing a preferred embodiment of the present invention. It is a partially cutaway side view showing a preferred embodiment of the present invention. It is explanatory drawing which shows the state which a permanent magnet scans on an engine block. It is a graph which shows the voltage output from a load meter when scanning the engine block of 4 cylinders without a missing cylinder liner in about 1.5 seconds. It is a graph which shows the load value which the load meter detected when scanning the engine block from which the cylinder liner of the 2nd cylinder was missing from the start end to the end.

Explanation of symbols

3 Load meter 5 Permanent magnet
10 Inspected object
11 Magnetic metal parts

Claims (5)

  The magnetic metal member of the object to be inspected that does not float due to the attracting force of the permanent magnet attracts the permanent magnet arranged at a certain distance from the object to be inspected, and the force by which the permanent magnet is attracted is used as a load meter. A method for detecting a loss of a magnetic metal member by transmitting and detecting a loss of the magnetic metal member.   A permanent magnet that is arranged at a certain distance from a test object that does not float due to the attracting force of the permanent magnet, and a force applied to the permanent magnet by being attracted to the magnetic metal member of the test object are directly detected. A magnetic metal member missing detection device comprising a load meter.   The missing detection device for a magnetic metal member according to claim 2, wherein the permanent magnet and the object to be inspected are relatively moved to perform scanning.   The missing of the magnetic metal member according to claim 2 or 3, wherein two permanent magnets are opposed to the outer diameter position of the cylindrical magnetic metal member and are arranged so as to be orthogonal to the scanning direction. Detection device.   5. The missing detection device for a magnetic metal member according to claim 4, wherein the permanent magnets have different polarities.

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