JP5448375B2 - Magnetic attractive force measuring device and magnetic attractive force measuring method - Google Patents

Description

  The present invention relates to a magnetic attraction force measuring apparatus and a magnetic attraction force measuring method used for measuring the magnetic attraction force of a magnet that is capable of attracting an object to be attracted containing a ferromagnetic metal material.

  In the magnetic sorting device, when removing the ferromagnetic metal foreign matter from the material to be sorted, generally, a magnetic attraction force is applied from the permanent magnet to the material to be sorted to attract the metal foreign matter from the sorting target, It has been removed. For this reason, in the magnetic sorting device, it is important to manage the magnetic attractive force of the permanent magnet, and in order to achieve the desired performance, it is essential that the magnetic attractive force of the permanent magnet is within a preset management range. Become.

  Conventionally, as a device for measuring the magnetic attractive force of a permanent magnet as described above (magnetic attractive force measuring device), as described in Patent Document 1, a permanent magnet to be measured by a tensile tester. (Magnetic to be measured) and magnetic yoke are pulled in a magnetically attracted state to measure the load when they are separated, or the Hall element is in contact with or close to the surface of the measured magnet A device that measures the magnetic flux density of an open magnetic path formed near the surface of a magnet to be measured by a Hall element is known.

Here, the magnetic attraction force measuring device using the tensile tester directly measures the magnitude of the magnetic attraction force that the magnet under measurement acts on the magnetic yoke. However, the measuring device uses a Hall element. Simply measures the magnetic flux density.
Japanese Patent Laid-Open No. 5-264702

However, according to the research and investigation by the inventors of the present application, the magnetic attraction force measured while the magnet to be measured is in contact with the magnetic material and the magnetic flux density measured near the surface of the magnet to be measured are It became clear that it is not always suitable as an index of how much force can be sucked from what distance. That is, even if the magnetic attraction force measured in a state where the measured magnet is in contact with the magnetic material or the magnetic flux density measured near the surface of the measured magnet, the measured magnet is determined based on these measured values. It is impossible to accurately evaluate the magnitude of the magnetic attractive force that acts on a metal foreign object that is a predetermined distance away.
The object of the present invention is to accurately reproduce the magnetic attractive force that the measured magnet acts on the reference attracting body in this state while reproducing the state where the measured magnet is separated from the object to be attracted by a predetermined distance in consideration of the above facts. An object of the present invention is to provide a magnetic attraction force measuring apparatus and a magnetic attraction force measuring method which can be measured well and easily.

According to a first aspect of the present invention, there is provided a magnetic attraction force measuring device having a shape corresponding to a metal foreign object to be sorted by a magnetic sorting device, and a reference attracting body that can be attracted by a magnetic attraction force of a magnet, and connected to the reference attracting body. A load measuring means for detecting a magnitude of a load acting on the reference adsorbent along a predetermined attraction direction, and supporting the load measuring means, wherein the reference adsorbent is an object for measuring magnetic attraction force. A frame member that is loaded on the measurement target magnet to be measured so as to face the measurement target magnet, and a frame member that is disposed on the frame member, along the suction direction from the measurement target magnet to the reference adsorbent When the measurement interval can be adjusted, a gap adjusting mechanism is provided.

  In the magnetic attraction force measuring apparatus according to claim 1, the gap adjusting mechanism arranged on the frame member can adjust the measurement interval along the attraction direction from the measured magnet to the reference attracting body. Since the distance (measurement distance) from the measured magnet to the reference attracting body along the attraction direction can be adjusted to a desired value while separating the magnet from the reference attracting body, for example, the measuring distance is measured If the length corresponding to the distance from the magnet to be attracted to the object to be attracted is set in the device in which the magnet is used, this state is reproduced while approximating the conditions under which the magnet to be measured is actually used. In this state, the magnetic attraction force that the magnet to be measured acts on the reference attracting member can be accurately and easily measured by the load measuring means.

  At this time, for example, as a reference adsorbent connected to the load measuring means, one that approximates physical attributes such as the shape, material, and size of the object to be adsorbed or has a corresponding physical attribute is selected. Then, under the conditions in which the magnet to be measured is actually used, a measurement value of the magnetic attraction force accurately corresponding to the magnetic attraction force actually acting on the object (substance) attracted by the magnet to be measured is obtained. It is done.

  In addition, even when the distance from the magnet to be attracted to the object to be attracted is longer than the maximum value of the measurement interval under conditions where the magnet to be measured is actually used, the magnet to be measured is changed step by step. By measuring the magnetic attraction force of a plurality of times, a relational expression between the measurement interval and the magnetic attraction force can be obtained by a technique such as multiple regression, so it is actually used based on this relational expression. It is also possible to accurately estimate the magnetic attractive force that the measured magnet acts on the object to be attracted under the conditions.

The magnetic attraction force measuring apparatus according to claim 2 of the present invention is the magnetic attraction force measuring apparatus according to claim 1, wherein the load measuring means includes a plurality of the shape, material and size different from each other. One reference adsorbent selected from the reference adsorbents is connected.
The magnetic attraction force measuring apparatus according to claim 3 of the present invention is the magnetic attraction force measuring apparatus according to claim 1 or 2 , wherein the gap adjusting mechanism is loaded with the frame member on the magnet to be measured. And a gauge member for displaying the measurement interval.

A magnetic attraction force measuring method according to claim 4 of the present invention is a magnetic attraction force measuring method for a magnet to be measured used in the magnetic attraction force measuring device according to any one of claims 1 to 3 , A loading process for loading a frame member into the magnet to be measured , and a shape corresponding to a metal foreign object to be sorted by the magnetic sorting device from the magnet to be measured by the gap adjusting mechanism in a state where the frame member is loaded into the magnet to be measured. The gap adjusting step for adjusting the measurement interval along the suction direction to the reference adsorbing body to a predetermined length and the magnetic attraction force acting on the reference adsorbing body by the magnet to be measured are applied to the load measuring means. And a measuring step of detecting as a load acting on the reference adsorbent.

  As described above, according to the magnetic attraction force measuring apparatus and the magnetic attraction force measuring method according to the present invention, the measurement target is reproduced in this state while reproducing the state in which the magnet to be measured is separated from the object to be attracted by a predetermined distance. The magnetic attractive force that the magnet acts on the reference attracting body can be measured accurately and easily.

Hereinafter, a magnetic attraction force measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a magnetic attraction force measuring device according to an embodiment of the present invention and a permanent magnet to be measured by the magnetic attraction force measuring device. The magnetic attraction force measuring apparatus 10 includes a measurement frame 12 formed in a substantially U-shape as a whole and a load measuring instrument 14 arranged inside the measurement frame 12. Here, the measurement frame 12 and the load measuring device 14 constitute a frame member and a load detection unit according to the present invention, respectively.

  As shown in FIG. 1B, the measurement frame 12 is provided with cylindrical column members 16 at both ends along the width direction (arrow W direction) of the apparatus. The column member 16 has a central axis parallel to the height direction (arrow H direction) of the device orthogonal to the width direction W, and the pair of column members 16 have the same dimension along the height direction H. It is a thing. A protective pad 18 formed in the shape of a thick disk is fixed to the pair of column members 16 at the lower end surfaces thereof. The lower end surfaces of the pair of protective pads 18 are contact surfaces 20 with respect to the permanent magnet 100 that is a measurement target of a magnetic attractive force described later.

  Here, although the protective pad 18 has a lower surface hardness than the permanent magnet 100 such as hard urethane, even if it receives an external load along the height direction H when measuring the magnetic attraction force, the dimensional change due to deformation is sufficient. Molded with a small material. Further, the top surface portions of the pair of column members 16 are respectively closed by a disk-shaped lid member 22, and screw holes 24 penetrating in the height direction H are formed in the lid member 22. The protective pad 18 can be exchanged for a shape (for example, a curved surface or a spherical surface) whose contact surface 20 corresponds to the surface shape of the permanent magnet 100 to be measured.

  In the measurement frame 12, a connection plate 26 is disposed at an upper end portion along the height direction H, and a holder plate 28 is disposed on the upper surface side of the connection plate 26. The connecting plate 26 is formed in a substantially rectangular flat plate shape having the width direction W as a longitudinal direction, and a lower bearing hole 32 penetrating in the height direction is formed in the central portion along the width direction W. Insertion holes 30 penetrating in the height direction H are formed at both ends.

  The holder plate 28 is formed with a holder portion 34 that is bent in a substantially U-shape in a direction away from the connection plate 26 at the center portion in the width direction W. The holder portion 34 is provided with an upper bearing hole 36 that coincides with the lower bearing hole 32 of the connecting plate 26 along the width direction W and the direction of the device (in the direction of arrow D in FIG. 1A). Further, at both ends of the holder plate 28 in the width direction W, insertion holes 38 respectively corresponding to the pair of insertion holes 30 in the connecting plate 26 are formed.

  Both ends of the connecting plate 26 are abutted against the lid member 22 of the pair of column members 16, and a holder plate 28 is laminated on the connecting plate 26. A connection bolt 40 is inserted into the insertion hole 38 of the holder plate 28 and the insertion hole 30 of the connection plate 26 corresponding to the insertion hole 38, and the front end side of the connection bolt 40 is sufficiently inserted into the screw hole 24 of the lid member 22. It is screwed in until a large fastening torque is generated. As a result, the pair of column members 16 are coupled to each other with sufficient strength via the coupling plate 26 and the holder plate 28. That is, the measurement frame 12 is assembled by a pair of column members 16, and a connection plate 26 and a holder plate 28 that connect the pair of column members 16.

  As shown in FIG. 1A, a pair of guide plates 42 are fixed to the outer peripheral surfaces of the pair of column members 16 at inner end portions along the width direction W, respectively. Each of the pair of guide plates 42 extends in parallel with the height direction H, and extends linearly along the height direction H between the pair of guide plates 42 and along the depth direction D. A guide groove 44 having a constant width is formed. Here, the pair of guide plates 42 is disposed in an intermediate portion along the height direction H of the column member 16, and the pair of guide plates 42 in the one column member 16 and the pair of guide plates in the other column member 16. 42, the position along the height direction H and the depth direction D corresponds.

  On the other hand, the load measuring instrument 14 includes a measuring instrument main body 50 and a holder casing 52 for storing the measuring instrument main body 50. The holder casing 52 is formed in a substantially cubic shape with most of the front end side (the front side in FIG. 1B) opened along the depth direction D. The holder casing 52 closes the upper cover 54 inserted into the upper end side of the measuring instrument main body 50, the lower cover 56 inserted into the lower end side of the measuring instrument main body 50, and the back surfaces of the upper cover 54 and the lower cover 56, respectively. In addition, a back plate 58 for connecting the upper cover 54 and the lower cover 56 is provided.

  In the back plate 58, the dimension of the back plate 58 along the width direction W is longer than the dimensions of the upper cover 54 and the lower cover 56. The back plate 58 has an upper cover 54 and a lower cover at both ends thereof, respectively. An extension guide portion 60 extending outward in the width direction with respect to 56 is formed. The pair of extended guide portions 60 are inserted into the guide grooves 44 at their distal ends. Here, as shown in FIG. 1A, the thickness of the extended guide portion 60 is slightly thinner than the width of the guide groove 44, and the distance between the tips of the pair of extended guide portions 60. Is slightly shorter than the distance between the bottom surfaces of the pair of guide grooves 44. As a result, the extended guide portion 60 can move only in the height direction H along the guide groove 44.

  The measuring instrument main body 50 includes, for example, a strain sensor, a load sensor (for example, one or a plurality of strain gauges fixed to the strain generator, and a resistance measurement unit that measures a change in electric resistance of the strain gauge). This load sensor calibrates the change in the electrical resistance measured by the resistance measuring unit, thereby calibrating the external load acting on the strain body (in this embodiment, the tensile load). To detect. Further, the measuring instrument main body 50 is provided with an operating unit 64 on the front panel 62 on the front side for the operator to turn on / off the operating power, set the tare (initialize), and issue a measurement start command. A display unit 66 for displaying an external load (measured value) detected by the load sensor is disposed below the display unit 66.

  A rod-shaped joint member 68 is disposed on the measuring instrument main body 50 so as to protrude downward on the bottom plate portion. A load transmitting member (not shown) having one end connected to the strain body of the load sensor and the other end connected to the joint member 68 is disposed inside the measuring device main body 50. Thereby, in the measuring instrument main body 50, an external load substantially parallel to the height direction H is transmitted to the joint member 68, and this external load is transmitted to the strain body of the load sensor via the load transmission member. At this time, the load sensor detects the magnitude of the external load by measuring the change in the electrical resistance of the strain gauge where the strain has occurred. In this embodiment, a metal resistor type strain gauge is used as an external load detection element, but other strains such as a piezoelectric element type, a semiconductor type, a surface acoustic wave type, a magnetostrictive type, and an optical fiber type are also available. A gauge may be used.

  The magnetic attraction force measuring apparatus 10 includes a reference cartridge 70 that is detachably connected to a joint member 68 of the measuring instrument main body 50. The reference cartridge 70 is provided with a round bar-shaped connecting shaft portion 72 on the upper end side thereof, and a reference adsorbing body 74 connected and fixed to the lower end portion of the connecting shaft portion 72. The upper end of the connecting shaft portion 72 can be connected to the inner peripheral side of the joint member 68 by screwing or the like, and can be detached from the joint member 68 as necessary. The joint member 68 is preferably made of a nonmagnetic metal material such as a copper alloy or austenitic stainless steel in order to avoid the influence of the magnetic attractive force from the permanent magnet 100. On the other hand, the reference attracting body 74 is basically made of a ferromagnetic metal material and can be attracted by the magnetic attractive force of the permanent magnet 100.

The connecting shaft 72 can be deformed in the bending direction of a wire, a chain, or the like in order to prevent the reference attracting body 74 from being pushed up by the permanent magnet 100 when the measurement frame 72 is loaded on the permanent magnet 100. An axial member may be used. However, as the shaft-shaped member that can be deformed in the bending direction, it is necessary to use a member that does not deform in the tension direction and the compression direction.
In the magnetic attraction force measuring apparatus 10, a plurality of reference cartridges 70 having different shapes, materials, and sizes of the reference attracting body 74 are prepared in advance, and when measuring the magnetic attraction force with respect to the permanent magnet 100, this permanent magnet is provided. The reference adsorption body 74 corresponding to the adsorption object assumed to be adsorbed by 100 is selected, and the reference adsorption body 74 is connected to the measuring instrument main body 50 via the connection shaft portion 72 and the joint member 68.

  FIG. 1 shows an example in which the reference adsorber 74 having a substantially spherical shape is connected to the measuring device main body 50. The reference adsorbing body 74 is made of, for example, an iron-based metal such as low carbon steel, but other ferromagnetic metals such as ferritic stainless steel and martensitic stainless steel depending on the material of the object to be adsorbed. May be used as a material. Further, the reference adsorbing body 74 may be one that does not contain a ferromagnetic metal as long as it can be adsorbed by the permanent magnet 100. For example, the surface of the ferromagnetic metal is made of another material such as a resin material or a nonmagnetic metal. It may be coated or coated.

  Further, in order to increase the measurement accuracy with respect to the magnetic attraction force acting on the object to be attracted by the permanent magnet 100, the reference attracting body 74 having a shape corresponding to the object to be attracted is used for the reason described later. It is desirable. Here, when the shape is the same and the dimensions are the same, the shape of the reference adsorbent 74 corresponding to the object to be adsorbed is the same, but the dimensions are different (similar), the shapes are similar, and The case where a dimension (volume) is substantially the same is mentioned.

  As shown in FIG. 1B, the base end portion of the screw shaft 76 is connected and fixed to the top plate portion 53 of the holder casing 52 via a nut 78. The screw shaft 76 has an axial center coinciding with the height direction H, and a tip end side is a feed screw portion 80 in which a thread groove is formed on the outer peripheral surface. The feed screw portion 80 of the screw shaft 76 passes through the connecting plate 26 and the holder plate 28 through the lower bearing hole 32 and the upper bearing hole 36, respectively. An adjustment nut 82 formed in a substantially thick disk shape as a whole is rotatably accommodated in the holder portion 34 of the holder plate 28. A female screw hole 84 passes through the center of the adjustment nut 82 along the height direction H, and a feed screw part 80 of the screw shaft 76 is screwed into the female screw hole 84. Here, the connecting plate 26, the holder portion 34, the screw shaft 76, and the adjusting nut 82 constitute a gap adjusting mechanism according to the present invention.

  On the outer peripheral surface of the adjusting nut 82, a gripping rotation portion 86 having a large outer diameter with respect to both ends is integrally formed at an intermediate portion along the axial direction. ), A part on the outer peripheral side protrudes forward and backward with respect to the holder portion 34, respectively. In the magnetic attraction force measuring device 10, the operator measuring the magnetic attraction force rotates the adjustment nut 82 while holding the holding rotation unit 86, so that the load measuring device 14 is moved in the height direction H with respect to the measurement frame 12. Are moved in a direction (upward or downward) corresponding to the rotation direction of the adjustment nut 82 by a distance corresponding to the rotation amount of the adjustment nut 82. At this time, since the holder casing 52 is guided in the height direction H along the guide grooves 44 provided in the pair of column members 16, the load measuring instrument 14 is displaced in the depth direction D and the width direction W ( (Slanting) is prevented, and the straight line moves reliably in the height direction H by a distance accurately corresponding to the amount of rotation of the adjusting nut 82.

  In the holder casing 52, a gauge plate 88 is fixed to a side surface portion on one end side (right side in FIG. 1) of the upper cover 54 so as to protrude outward in the width direction W. The gauge plate 88 is formed with a substantially isosceles triangular pointer portion 90 that gradually decreases in width toward the outer side in the width direction. Further, as shown in FIG. 1B, the front guide plate 42 disposed on the column member 16 on one end side has a gauge portion 92 extending along the height direction H on the front surface portion thereof. Is provided. A scale is printed on the gauge portion 92 at regular intervals (for example, 1 mm intervals) along the height direction H. Thereby, when the load measuring instrument 14 moves along the height direction H with respect to the measurement frame 12, the operator reads the change in the scale of the gauge portion 92 pointed to by the pointer portion 90 before and after the movement, thereby measuring the load. The amount of relative movement of the instrument 14 with respect to the measurement frame 12 can be easily measured.

Next, a method for measuring the magnetic attraction force of the permanent magnet 100 using the magnetic attraction force measuring apparatus 10 configured as described above will be described.
When the magnetic attraction force of the permanent magnet 100 is measured by the magnetic attraction force measuring device 10, first, the operator first contacts the contact surfaces of the pair of column members 16 in the measurement frame 12 as shown in FIG. 20 is brought into close contact with the attracting surface 101 of the permanent magnet 100. In this state, the operator rotates the adjustment nut 82 as appropriate to adjust the position of the reference adsorption body 74 so as to be in contact with the adsorption surface 101 as shown by the solid line in FIG. Next, the operator visually recognizes the scale of the gauge portion 92 pointed to by the pointer portion 90, and then rotates the adjustment nut 82 to separate the reference adsorption body 74 from the adsorption surface 101, which is indicated by a two-dot chain line in FIG. As described above, a predetermined gap (measurement interval G) is formed between the reference adsorbing body 74 and the adsorbing surface 101.

  Here, the measurement interval G is, for example, an actual interval (actual machine interval) between the adsorption surface 101 of the permanent magnet 100 and an object to be adsorbed such as metal debris in an industrial apparatus such as a magnetic sorting apparatus in which the permanent magnet 100 is used. And it sets according to the reduced scale of the reference | standard adsorption body 74 with respect to an adsorption | suction target object. Specifically, when the scale of the reference adsorbent 74 with respect to the adsorption object is 1/1, the measurement interval G is set to coincide with the actual machine interval, and the scale of the reference adsorbent 74 with respect to the adsorption object is set. In cases other than 1/1, a calibration value obtained by calibrating the actual machine interval according to the scale is set as the measurement interval G. In an industrial apparatus, when the actual machine interval is variable continuously or stepwise, a plurality of measurement intervals G are set stepwise according to the range of the actual machine interval.

After the adjustment of the measurement interval G is completed, the operator performs a predetermined operation on the operation unit 64 of the measuring device main body 50 to thereby apply an external load (magnetic attraction force) acting on the reference attracting body 74 from the permanent magnet 100. ) Measurement starts. As a result, the measuring instrument main body 50 displays the magnetic attractive force detected by the load sensor on the display unit 66. When a plurality of measurement intervals G are set, the operator once sets the measurement frame 12 apart from the permanent magnet 100, sets the tare for the measuring instrument body 50, and then sets other measurement intervals G. By repeating the above operation, the magnetic attractive force at other measurement intervals G is measured.
Even when a plurality of measurement intervals G are set, the measurement interval G is adjusted stepwise (for example, 10 mm, 15 mm, and 20 mm) by the adjustment nut 82 without separating the measurement frame 12 from the permanent magnet 100. The magnetic attraction force may be measured by the measuring device main body 50 while being adjusted to G between each measurement.

  In the magnetic attraction force measuring apparatus 10 according to the present embodiment described above, the adjusting nut 82 and the screw shaft 76 configured as a gap adjusting mechanism are arranged in the height direction H (from the attracting surface 101 of the permanent magnet 100 to the reference attracting body 74 ( The measurement interval G along the suction direction) can be adjusted, so that the measurement distance G from the permanent magnet 100 along the suction direction to the reference attracting body 74 is desired while the permanent magnet 100 is separated from the reference attracting body 74. Therefore, for example, the measurement distance G is set to a length corresponding to the distance (actual machine interval) from the permanent magnet 100 to the object to be attracted in an apparatus in which the permanent magnet 100 is actually used. In this way, while reproducing the state that approximates the condition in which the permanent magnet 100 is actually used, the magnet that the permanent magnet 100 acts on the reference attracting body 74 in this state. The suction force accurately by the load measuring instrument 14, and can be easily measured.

  At this time, for example, the reference adsorbent 74 connected to the load measuring device 14 approximates the physical attributes such as the shape, material, and size of the actual adsorption object, or the corresponding physical attributes. If the one having the magnetic attraction force is selected, the measured value of the magnetic attraction force corresponding to the magnetic attraction force actually applied to the object to be attracted by the permanent magnet 100 under a condition in which the permanent magnet 100 is actually used is accurately obtained. can get.

Further, even when the actual machine interval under the condition where the permanent magnet 100 is actually used is longer than the maximum value of the measurement interval G adjusted by the adjustment nut 82 and the screw shaft 76, the actual machine interval is set to an appropriate natural number. By measuring the magnetic attraction force of the permanent magnet 100 a plurality of times while changing the measurement interval G step by step for each divided value, the relationship between the measurement interval G and the magnetic attraction force by a method such as multiple regression. Since the equation can be obtained, it is possible to accurately estimate the magnetic attraction force that the permanent magnet 100 acts on the object to be attracted under the conditions actually used based on this relational equation.
As a result, according to the magnetic attraction force measuring apparatus 10 according to the present embodiment, the state in the apparatus in which the permanent magnet 100 in which the permanent magnet 100 is separated from the object to be attracted by a predetermined distance is actually used is approximately reproduced. However, the magnetic attractive force that the permanent magnet 100 acts on the reference attracting body 74 in this state can be measured accurately and easily.

Next, a magnetic attraction force measuring method using the magnetic attraction force measuring apparatus 10 according to the present embodiment described above will be theoretically described.
The inventors of the present application have measured the magnetic flux density (Gaussian value) near the surface of the permanent magnet by a method of measuring the load when the magnet to be measured that is in close contact with the conventional reference adsorbent is separated from the reference adsorbent. Considering that the measurement method cannot accurately measure the distance to which the object is attracted and how much force (magnetic attraction force) can be attracted, the force index method ( A magnetic attraction force measuring method and a magnetic attraction force measuring apparatus according to the present embodiment using the Force Index Method have been developed. First, the force index method will be briefly described.

As a known knowledge, in a uniform magnetic field, the magnetic attraction force does not act on the adsorption target without being affected by the strength, and the magnetic attraction force acts on the adsorption target. Magnetic field inhomogeneity (tilt) is required. That is, it can be considered that the magnitude of the magnetic attractive force acting on the object to be attracted can be properly evaluated not by the intensity of the magnetic field itself but by the differential value of the Gaussian value. The differential value of the Gaussian value is a force index (FI), and this FI is expressed by the following equation (1).
FI = B (ΔB / Δx) (1)
Here, B is the strength of the magnetic field, ΔB is the amount of change in the magnetic field, and Δx is the distance.
And if the inventors of this application evaluate the magnetic attraction force of the to-be-measured magnet (permanent magnet 100) by said FI, when the magnetic attraction force, shape, or structure of the permanent magnet 100 differs, Even when the shape, size (weight), or material is different, it has been found that the magnetic attractive force that the permanent magnet 100 acts on the object to be attracted can be appropriately evaluated. This point will be described more specifically.

(1) Shape of object to be adsorbed Iron spheres, cubes and elongated rods having a constant weight are each placed on a test bench as objects to be adsorbed so that their centers of gravity are located on the same horizontal plane. When the permanent magnet 100 is installed at a sufficient distance above these objects to be attracted and the permanent magnet 100 is lowered toward the test table at a low speed, it acts on any one object to be attracted at a certain point. When the permanent magnet 100 is lowered even at a minute distance, only one of the objects to be attracted is attracted by the permanent magnet 100. At this time, the order of adsorption to the permanent magnet 100 is in the order of a rod-shaped body, a cube, and a sphere. From this, even if the weight is the same, it is easily understood that the magnetic attractive force received from the permanent magnet 100 is larger for the attracted object having a large surface area.

(2) Weight of adsorption object As shown in FIG. 2, as an adsorption object, a cube 102 having a side length of 10 mm and a cube 104 having a length of 100 mm are respectively placed on a test bench 106, and these The centers of gravity of the cubes 102 and 104 are positioned on the same horizontal plane. In FIG. 2, F1 and F2 are magnetic attractive forces acting on the cube 102 and the cube 104 by the permanent magnet 100, W1 and W2 are gravity (weight) acting on the cube 102 and the cube 104, respectively, and GP1 and GP2 are It is the center of gravity of the cube 102 and the cube 104, respectively.

  When the permanent magnet 100 is installed at a sufficient distance above the cubes 102 and 104 and the permanent magnet 100 is lowered toward the test table at a low speed, the cubes 102 and 104 are within the measurement error range. At the same time, it is attracted to the permanent magnet 100. This is because the large cube 104 is composed of 1000 times as many iron atoms as the small cube 102, and the permanent magnet 100 acts on the cube 104 with a magnetic force 1000 times that of the cube 102, but the weight of the cube 104 is the cube 102. 1000 times the weight. For this reason, the timing at which the cubes 102 and 104 are attracted by the permanent magnet 100 is the same.

(3) Force Index Coefficient Considering the relationship between the shape and weight of the object to be attracted and the magnetic attraction force of the permanent magnet 100 described above, the ease of being attracted by the permanent magnet 100 for each shape of the object to be attracted is relatively set. A coefficient to be expressed (force index coefficient = FI coefficient) can be set.
The following (Table 1) shows the results of trial calculation of FI coefficients of various shapes of adsorption objects.

The graph of FIG. 3 conceptually shows the relationship between the magnetic flux density of two types of permanent magnets and the distance from the attracting surface, and the relationship between the force index (FI) and the distance from the attracting surface. .
The permanent magnet A has a magnetic flux density measured on the surface higher than that of the permanent magnet B, but the magnetic flux density with the permanent magnet B is reversed at a point of about 120 mm from the magnet surface. On the other hand, the FI measured at a point 20 mm from the magnet surface is also higher for the permanent magnet A than the permanent magnet B. It has become.

  Here, the FI coefficient of the sphere is 3000 as shown in (Table 1), and the FI level of 3000 is shown as a straight line L in FIG. The points lowered from the intersection of the straight lines L and FI to the broken lines A and B on the horizontal axis (distance from the magnet attracting surface) are 160 mm and 200 mm, respectively. These represent the distance (collection distance) at which the sphere can be attracted by the permanent magnet A and the permanent magnet B, respectively, and these values are obtained when the sphere is actually attracted by the permanent magnet A and the permanent magnet B. It is confirmed that the measured values agree with sufficient accuracy.

  Moreover, the following (Table 2) shows the result of calculating the collection distances of the permanent magnets A and B with respect to the adsorption objects of various shapes using the FI coefficient of the sphere. Even when the results shown in (Table 2) are compared with the measured values of the collection distances of the permanent magnets A and B with respect to various shapes of adsorption objects, the various shapes of adsorption objects calculated using the FI coefficient. It has been confirmed that the collection distance is consistent with the measured value with sufficient accuracy.

  Therefore, in the magnetic attraction force measuring apparatus 10 according to the present embodiment, if the shape of the adsorption target is roughly known, the size of the adsorption target does not match the reference adsorption body 74 or is permanent. Even when the measurement interval G from the magnet 100 to the reference attracting body 74 does not coincide with the actual machine interval in which the permanent magnet 100 is used, measurement is performed by the magnetic attraction force measuring device 10 by using the knowledge and FI coefficient shown in FIG. It is possible to convert the generated magnetic attractive force into a magnetic attractive force that the permanent magnet 100 acts on the object to be attracted in an apparatus in which the permanent magnet 100 is actually used.

It is the top view and front view which show the structure of the magnetic attraction force measuring apparatus which concerns on embodiment of this invention. It is a front view which shows schematic structure of the test apparatus used in order to clarify the relationship between the magnetic attraction force which a permanent magnet acts on a attracting target, and the magnitude | size of a attracting target. It is a graph which shows notionally the relationship between the magnetic flux density of two types of permanent magnets A and B and the distance from the attracting surface, and the relationship between the force index (FI) and the distance from the attracting surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Magnetic attraction force measuring device 12 Measurement frame 14 Load measuring device 16 Column member 18 Protection pad 20 Contact surface 22 Lid member 24 Screw hole 26 Connection plate 28 Holder plate 30 Insertion hole 32 Lower bearing hole 34 Holder part 36 Upper bearing hole 38 Insertion hole 40 Connecting bolt 42 Guide plate 44 Guide groove 50 Measuring instrument body 52 Holder casing 53 Top plate portion 54 Upper cover 56 Lower cover 58 Back plate 60 Extension guide portion 62 Front panel 64 Operation portion 66 Display portion 68 Joint member 70 Reference Cartridge 72 Connecting shaft portion 74 Reference adsorbent body 76 Screw shaft 78 Nut 80 Feed screw portion 82 Adjustment nut 84 Female screw hole 86 Holding rotation portion 88 Gauge plate 90 Pointer portion 92 Gauge portion 100 Permanent magnet 101 Adsorption surface 102, 1 4 cubic 106 test stand A permanent magnet B permanent magnet G measurement interval

Claims (4)

A reference adsorbent that has a shape corresponding to a metal foreign object to be sorted by a magnetic sorting device and can be attracted by a magnetic attraction force of a magnet,
A load measuring means connected to the reference adsorbent and detecting a magnitude of a load acting on the reference adsorbent along a predetermined suction direction;
A frame member loaded on the measurement target magnet to support the load measuring means and facing the measurement target magnet to be measured with respect to the magnetic attraction force.
A gap adjusting mechanism that is arranged on the frame member and can adjust the measurement interval along the suction direction from the magnet to be measured to the reference attracting body,
A magnetic attraction force measuring apparatus comprising:   2. The magnetic attraction according to claim 1, wherein said load measuring means is connected to one reference adsorbent selected from a plurality of said reference adsorbents having different shapes, materials and sizes. Force measuring device. Wherein the gap adjusting mechanism, the the frame member is loaded to the measured magnet, the magnetic attraction force measuring device according to claim 1 or 2, wherein the having the gage member for displaying the measurement interval. A magnetic attraction force measuring method for a magnet to be measured used in the magnetic attraction force measuring device according to any one of claims 1 to 3 ,
A loading step of loading a frame member into the magnet to be measured;
With the frame member loaded in the magnet to be measured,
A gap adjusting step for adjusting a measurement interval along a suction direction from a magnet to be measured to a reference adsorbent having a shape corresponding to a metal foreign object to be sorted by a magnetic sorting device to a predetermined length by the gap adjusting mechanism;
A measuring step of detecting a magnetic attractive force acting on the reference adsorbent by the magnet to be measured as a load acting on the reference adsorbent by a load measuring means;
A magnetic attraction force measuring method characterized by comprising:

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