JP2010110851A - Magnet fixing tool and rare earth magnet cutting device including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively supply a small amount of grinding fluid to a cutting point and perform highly accurate cutting at high speed, in the multiple cutting of rare earth magnet. <P>SOLUTION: This magnet fixing tool 31 is used for fixing rare earth magnet m when the rare earth magnet m is cut by a multiple cutting grinding blade 1 for cutting the rare earth magnet m constituted by arranging a plurality of cutting grinding blades including grinding outer peripheral blades on the outer peripheral edge of a thin plate disc-shaped or thin plate doughnut disc-shaped base plate in a rotating shaft in the axial direction of the rotating shaft at predetermined intervals. The magnet fixing tools can press the rare earth magnet m on the cutting direction and fix them and are constituted in pairs. A plurality of guide grooves 31a corresponding to the cutting grinding blades, respectively are formed on the surface of one or both of the magnet fixing tools 31, so that the outer peripheries of the respective cutting grinding blades can be inserted into the guide grooves 31a. Thus, in the multiple cutting of the rare earth magnet m, smaller amount of the grinding fluid can be effectively supplied to the cutting point compared with conventional cases and highly accurate cutting can be performed at high speed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnet fixing jig for fixing a rare earth magnet when multi-cutting a rare earth magnet alloy, and a rare earth magnet cutting processing apparatus including the same.

  When manufacturing rare earth magnet products, there are cases where a single piece is made in a shape that is almost the same as the product shape at the press molding stage, and cases where it is formed into a large block shape and cut in a machining process (multiple pieces). is there. The conceptual diagram is shown in FIG. In the case of the single piece shown in FIG. 1A, the molded product 101, the sintered / heat treated product 102, and the processed product (product) 103 are substantially the same in shape and size, and are normally sintered. If it is possible, it is possible to obtain a sintered body having a near net shape with a relatively small processing step. However, when manufacturing a small product or a product with a thin magnetization direction, it is difficult to obtain a sintered body having a normal shape in press molding and sintering, which tends to cause a deterioration in yield, and cannot be manufactured in severe cases. End up.

  On the other hand, in the case of the multi-cavity shown in FIG. 1 (b), there is no problem as described above, and the productivity is high in the processes such as press molding, sintering and heat treatment, and it is versatile. It has become mainstream in magnet production. However, in this case, the molded product 101 and the sintered / heat-treated product 102 have almost the same shape and size, but a cutting process is necessary at the subsequent processing, and how efficient and efficient the cutting process is. Thus, whether the processed product 103 can be obtained is an important point.

  As cutting blades for rare earth magnets, diamond grinding stone inner peripheral blades with diamond abrasive grains bonded to the inner peripheral part of a thin donut-shaped disk, or diamond grinding stones with diamond abrasive grains fixed to the outer peripheral part using a thin disc as a base plate There are two types of peripheral blades. Recently, cutting using the peripheral blade has become the mainstream particularly from the viewpoint of productivity. That is, in the case of the inner peripheral blade, single-blade cutting and productivity is low, whereas in the case of the outer peripheral blade, for example, as shown in FIG. A plurality of outer peripheral blades 11 fixed to the grindstone base plate 11b are attached to a rotary shaft (shaft) 12 via spacers (not shown), and a multi-cutting blade 1 assembled is used so that a large number can be obtained at a time. This is because multi-cutting is possible.

  Three types of binders for diamond abrasive grains of such outer peripheral blades, resin bond as a resin binder, metal bond as a metal binder, and electrodeposition by plating, are typical and widely used for cutting rare earth magnets. ing.

  When cutting a rare earth magnet using a cutting wheel, when cutting a block of a certain size and cutting a large number of products, the blade thickness of the cutting wheel and the workpiece (rare earth magnet) The relationship with the material yield is very important. Use a thin blade as much as possible, and cut with high precision to reduce the cutting cost, reduce the cutting waste, increase the number of products obtained, and increase the material yield. It is important to improve sex.

  In order to obtain a thin cutting blade from the viewpoint of material yield, it is naturally necessary to make the grindstone base plate thin. In the case of the outer peripheral blade 11 as shown in FIG. 2, steel materials are conventionally used mainly from the viewpoint of material cost and mechanical strength as the material of the grindstone base plate 11b. Alloy tool steels defined by JIS standards as SK, SKS, SKD, SKT, SKH, etc. have been used exclusively. However, when trying to cut a hard material such as a rare earth magnet with a thin outer peripheral blade, the above-described conventional alloy tool steel plywood lacks mechanical strength, and deforms such as a curve during cutting, resulting in loss of dimensional accuracy. .

  As a measure to improve this, cutting for rare earth magnet alloys using a base metal made of cemented carbide, and bonding high-hardness abrasive grains such as diamond, cBN, etc. to the base metal with a binder of resin bond, metal bond and plating electrodeposition. A blade was developed (Patent Document 1: Japanese Patent Laid-Open No. 10-175172), and by using a cemented carbide as a base metal material, buckling deformation due to stress during processing is reduced, and a rare earth magnet can be cut accurately. It became so. However, when cutting rare earth magnets, if the supply of grinding fluid to the cutting edge is inadequate, even if a cemented carbide base metal is used, grinding wheel clogging or clogging will be induced and grinding resistance during processing will be reduced. Increases, and chipping and bending occur, which adversely affects the machining state.

  As countermeasures, there are a method in which a plurality of nozzles are arranged around the cutting blade and the grinding fluid is forcibly supplied to the cutting edge, and a method in which a large amount of grinding fluid is supplied from a large-capacity pump. In the cutting with the multi-cutting blade of the rare earth magnet in which a plurality of blades are arranged, the nozzle cannot be arranged around the cutting blade and is difficult to implement. In the latter method of supplying a large amount of grinding fluid, the grinding fluid is divided and scattered by the air flow around the blade due to the rotation of the cutting blade, and cannot be supplied to the core blade edge. Applying the grinding fluid at high pressure not only causes the grinding wheel to bend, but also impedes high-precision machining, such as causing vibration.

JP-A-10-175172 JP-A-7-171765 Japanese Patent Laid-Open No. 5-92420 Shinichi Ninomiya et al., Journal of Precision Engineering, Vol. 73, no. 7, 2007

  The present invention has been made in view of the above circumstances, and in multi-cutting of rare earth magnets, it is possible to effectively supply a small amount of grinding liquid to a cutting processing point as compared with the prior art and perform high-precision cutting at high speed. An object of the present invention is to provide a magnet fixing jig and a rare earth magnet cutting processing apparatus including the magnet fixing jig.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have determined that a cutting grindstone blade having a grindstone outer peripheral edge at the outer peripheral edge of a thin disc-like or thin donut disc-like base plate is used as a rotating shaft in its axial direction. As a jig for pressing and fixing the rare earth magnet in its cutting direction when rotating the plurality of cutting grindstone blades and multi-cutting the rare earth magnet, Alternatively, it has been found that a pair of magnet fixing jigs in which a plurality of guide grooves corresponding to each cutting grindstone blade are formed on both surfaces so that the outer peripheral portion of each cutting grindstone blade can be inserted is effective.

  Then, using this pair of magnet fixing jigs, when each cutting grindstone blade is rotated in a state where the outer peripheral portion of each cutting grindstone blade is inserted into each guide groove, The wobbling of the cutting wheel blade in the rotational axis direction is regulated, and the grinding fluid moved along with the surface of each cutting wheel blade from each slit portion of the grinding fluid supply nozzle flows into each guide groove, The grinding fluid that flows into each guide groove is efficiently supplied to each cutting edge of the cutting wheel blade along with the surface of each rotating cutting wheel blade. It has been found that the grinding fluid can be effectively supplied to the cutting point of the rare earth magnet to perform high-precision cutting at high speed.

Accordingly, the present invention provides the following magnet fixing jig and a rare earth magnet cutting processing apparatus including the same.
Claim 1:
Cutting a rare earth magnet formed by arranging a plurality of cutting wheel blades having a grinding wheel outer peripheral edge at the outer peripheral edge of a thin disk or thin donut disk base plate at a predetermined interval along the axial direction of the rotating shaft. A magnet fixing jig for fixing the rare earth magnet when cutting the rare earth magnet with a multi-cutting grindstone blade for
A pair of rare earth magnets can be pressed and fixed in the cutting direction, and a plurality of guide grooves corresponding to each cutting wheel blade can be inserted into one or both surfaces of each pair of cutting wheel blades. A magnet fixing jig, characterized in that it is formed.
Claim 2:
2. The magnet fixing jig according to claim 1, wherein the guide groove of the magnet fixing jig is formed with a length from the rare earth magnet in a state where the rare earth magnet is fixed to 1 mm or more and 100 mm or less.
Claim 3:
The width of the guide groove of the magnet fixing jig is greater than Wmm and equal to or less than (W + 6) mm with respect to the width W of the grinding wheel outer peripheral blade of the cutting grindstone blade. Magnet fixing jig.
Claim 4:
A rare earth magnet cutting apparatus comprising the magnet fixing jig according to any one of claims 1 to 3.

  According to the present invention, in multi-cutting rare earth magnets, it is possible to effectively supply a small amount of grinding fluid to the cutting processing point as compared with the prior art, and to perform high-precision cutting at high speed, and its utility value is industrially Very big.

Hereinafter, the present invention will be described in more detail.
In the present invention, a plurality of rare earth magnets are arranged at predetermined intervals along the axial direction of a cutting wheel blade provided with a grinding wheel outer peripheral blade at the outer peripheral edge of a thin disk-shaped or thin donut disk-shaped base plate. Then, the cutting is performed by a multi-cutting process in which the plurality of cutting wheel blades are rotated and cut.

  For this multi-cutting, a conventionally known cutting wheel for cutting an outer peripheral blade can be used. For example, as shown in FIG. 2, an abrasive grain portion (whetstone outer peripheral blade) 11a is formed on a thin plate donut on the outer peripheral edge portion. A plurality of outer peripheral blades (cutting grindstone blades) 11 fixed to the base plate 11b of the circular disk (in the case shown in FIG. 2 is 19 and the number is not limited, but is usually 2 to 100). ), And a multi-cutting blade (multi-cutting grindstone blade) 1 assembled and assembled to a rotary shaft (shaft) 12 via a spacer (not shown).

  The size of the base plate is not particularly limited, but the outer diameter is 80 to 200 mm, preferably 100 to 180 mm, the thickness is 0.1 to 1.0 mm, and particularly 0.2 to 0.8 mm. Preferably, when the base plate is a thin plate donut disc shape, the inner hole has a diameter of 30 to 80 mm, preferably 40 to 70 mm.

In addition, the material of the base plate of the multi-cutting grindstone blade may be any of the materials used for cutting blades such as SK, SKS, SKD, SKT, SKH, etc. It is preferable because it can be made. The cemented carbide used as the base plate includes carbide powders of metals belonging to groups IVB, VB, and VIB of the periodic table such as WC, TiC, MoC, NbC, TaC, Cr ₃ C ₂ , Fe, Co, Ni, Mo, Cu , Pb, Sn, or alloys bonded by sintering using these alloys are preferable, and among them, WC-Co, WC-Ni, TiC-Co, and WC-TiC-TaC-Co are typical. It is particularly preferable to use a new one.

  On the other hand, the abrasive grain part (grinding wheel outer peripheral blade) is formed so as to cover the outer peripheral edge part of the base plate, and examples of the abrasive grain part include those composed of abrasive grains and a binder. , CBN abrasive grains or mixed abrasive grains of diamond abrasive grains and cBN abrasive grains are bonded to the outer peripheral edge of the base plate. As the binder for the abrasive grains of the outer peripheral blade, three types of resin bonding as a resin binder, metal bond as a metal binder, and electrodeposition by plating are representative, and any of them may be used.

  The width of the abrasive grain part (grinding wheel outer peripheral blade) along the thickness direction of the base plate is (thickness of base plate + 0.01) mm to (thickness of base plate + 4) mm, particularly (thickness of base plate) +0.02) mm to (thickness of base plate +2) mm is preferable. Moreover, the protrusion length of the protrusion part which protrudes ahead from the baseplate of an abrasive grain part (grinding stone outer periphery blade) depends on the magnitude | size of the abrasive grain to fix, but is 0.1-10 mm, especially 0.3-8 mm. Preferably there is. Furthermore, it is preferable that the width | variety of the abrasive grain part (grinding stone outer periphery blade) along the radial direction of a base plate is 0.1-10 mm, especially 0.3-8 mm.

  In addition, the interval between the cutting wheel blades is appropriately set according to the thickness of the rare earth magnet after cutting, but is set slightly wider (for example, 0.01 to 0.4 mm wider) than the thickness of the rare earth magnet after cutting. Is preferred.

  The number of revolutions of the cutting grindstone blade at the time of cutting is preferably, for example, 1,000 to 15,000 rpm, particularly 3,000 to 10,000 rpm.

  In multi-cutting processing of rare earth magnets, cutting is performed by supplying a grinding fluid to a cutting grindstone blade. In the present invention, an introduction port for the grinding fluid is formed on one end side, and each of the above-mentioned cuttings on the other end side. It is preferable to use a grinding fluid supply nozzle in which a plurality of blade insertion slits corresponding to the grindstone blade are formed and the outer periphery of each cutting grindstone blade can be inserted into each of the slits.

  As shown in FIGS. 3 and 4, the grinding fluid supply nozzle 2 is composed of a hollow grinding fluid supply nozzle main body 2a and a grinding fluid introduction channel 2b, and one end of the grinding fluid introduction channel 2b is provided at one end. An opening 22 is formed to provide an inlet 22 for the grinding fluid, and the other end is attached to a side surface on one end side of the grinding fluid supply nozzle body 2a, and communicates with a hollow portion (a liquid pool) 23 of the grinding fluid supply nozzle body 2a. Yes. On the other hand, the grinding fluid supply nozzle body 2a has a number corresponding to the number of cutting wheel blades on the other end side (usually the same number as the number of cutting wheel blades of the multi cutting wheel blade, In the case of what is shown in FIG. 4, it is 19 and the number is not limited, but is usually 2 to 100). Note that in order to adjust the amount of the grinding liquid ejected from the slit, the number of slits may be larger than the number of blades so that a slit into which no blade is inserted remains when the nozzle is used.

  As will be described later, the outer peripheral portion of each cutting grindstone blade is inserted into each slit 21 of the grinding fluid supply nozzle 2. Therefore, the interval between the slits 21 is set so as to correspond to the interval between the individual cutting grindstone blades of the multi-cutting grindstone blade described above, and is formed in a straight line and in parallel with each other.

  Further, the shape and position of the grinding fluid supply nozzle, its slit and the grinding fluid introduction port are not limited to those shown in FIGS. 3 and 4, and for example, the grinding fluid supply nozzle shown in FIG. 5 is exemplified. You can also The grinding fluid supply nozzle 2 is composed of a hollow grinding fluid supply nozzle main body 2a and a grinding fluid introduction channel 2b, and the grinding fluid introduction channel 2b is opened at the upper end to provide a grinding fluid introduction port 22. None, and the lower end is attached to the upper surface of one end side of the grinding fluid supply nozzle body 2a, and communicates with the hollow portion (puddle) 23 of the grinding fluid supply nozzle body 2a. On the other hand, the number of grinding fluid supply nozzle main bodies 2a corresponding to the number of cutting wheel blades on the other end side (usually the same number as the number of cutting wheel blades of a multi-cutting wheel blade, In the case shown, the number is 19 and the number is not limited, but is usually 2 to 100). In addition, the upper surface of the grinding fluid supply nozzle body 2a is inclined downward toward the distal end side of the slit 21 at the other end side of the grinding fluid supply nozzle body 2a in which the slit 21 is formed. The thickness of the grinding fluid supply nozzle main body 2a (thickness of the hollow portion) is thin. Also in this case, the interval between the slits 21 is set so as to correspond to the interval between the individual cutting grindstone blades of the multi-cutting grindstone blade described above, and is formed in a straight line at a predetermined interval in parallel. In the case of this grinding fluid supply nozzle, since the slit side of the grinding fluid supply nozzle is thinly formed, the grinding fluid can be more vigorously supplied to the cutting wheel blade side. Also in this case, in order to adjust the amount of the grinding liquid ejected from the slit, the number of slits may be larger than the number of blades so that a slit into which no blade is inserted remains when the nozzle is used.

  Here, the outer peripheral portion of the cutting wheel blade inserted into the slit is caused by bringing the grinding fluid in contact with the cutting wheel blade into the surface (outer peripheral portion) of the cutting wheel blade and bringing the grinding fluid into each cutting point of the rare earth magnet. Will be supplied to. Therefore, the width of the slit needs to be formed wider than the width of the cutting grindstone blade (that is, the width of the grindstone outer peripheral blade). If the slit width is too wide, the grinding liquid cannot be effectively supplied to the cutting wheel blade side, and only the amount flowing down from the slit increases. It is preferable that the width W of the grindstone outer peripheral blade exceeds Wmm, preferably (W + 0.1) mm or more and (W + 6) mm or less.

  When the thickness of the slit forming portion 21a of the grinding fluid supply nozzle is small, the strength is weak, and the slit is easily deformed by contact with a cutting blade or the like, and there is a possibility that stable grinding fluid cannot be supplied. Yes, if the thickness is too thick, the flow path inside the grinding fluid supply nozzle cannot be secured, or even if the outer periphery of the cutting wheel blade is inserted, the outer periphery of the cutting wheel blade is sufficiently in contact with the grinding fluid inside the grinding fluid supply nozzle. There may be cases where contact cannot be made. Therefore, although it depends on the material for supplying the grinding fluid, it is preferably 0.5 to 10 mm for a plastic material and 0.1 to 5 mm for a metal material.

  On the other hand, the length of the slit is formed such that when the outer periphery of the cutting grindstone blade is inserted, the outer periphery of the cutting grindstone blade can be in sufficient contact with the grinding fluid inside the grinding fluid supply nozzle. Usually, a length of about 2 to 30% of the outer diameter of the base plate of the cutting grindstone blade is suitable. In addition, the slit is preferably substantially closed so that the slit does not contact the cutting grindstone blade in the state where the outer periphery of the cutting grindstone blade is inserted. The portion of the slit that is not clogged with the cutting wheel blade in the longitudinal direction with the outer periphery of the cutting wheel blade inserted so that it can be directly injected into the magnet fixing jig described later. May be left.

  Using such a grinding liquid supply nozzle, as shown in FIGS. 6 and 7, the outer peripheral portion of each cutting grindstone blade 11 of the multi-cutting grindstone blade 1 is inserted into each slit 21 of the grinding liquid supply nozzle 2. Then, the grinding fluid is introduced into the grinding fluid supply nozzle 22 through the inlet 22 and the cutting wheel blade is rotated while the grinding fluid is ejected from each slit, and the rare earth magnet m is cut by the outer peripheral edge of the cutting wheel blade. it can. The grinding fluid supply nozzle may be disposed to face the rare earth magnet via the cutting wheel blade, and when the grinding fluid supply nozzle is disposed above the rare earth magnet, the cutting wheel blade is connected to the grinding fluid supply nozzle. You may arrange | position in the position which passes a slit from upper direction to the downward direction, or may be arrange | positioned in the position which passes upward from the downward direction. 6 and 7, the configuration of each part of the multi-cutting grindstone blade 1 is denoted by the same reference numerals as those in FIG.

  It is advantageous to supply the grinding liquid by entrainment to the surface of the cutting wheel blade, while the slit between the grinding liquid supply nozzle and the rare earth magnet is not so far away. The distance between the slit of the grinding fluid supply nozzle and the rare earth magnet may be the barrier between the movement of the blade and rare earth magnet and the injection and discharge of the grinding fluid. Is preferably 1 to 50 mm (for example, in the illustrated example, the grinding liquid supply nozzle is positioned 1 to 50 mm higher than the upper surface of the rare earth magnet at the end of cutting).

  In this way, the multi-cutting grindstone blade, the grinding fluid supply nozzle, and the rare earth magnet are arranged, and either or both of the multi-cutting grindstone blade, the grinding fluid supply nozzle, and the rare earth magnet are rotated while the multi-cutting grindstone blade is rotated. The rare earth magnet can be cut by bringing the abrasive grain portion into contact with the rare earth magnet and moving it relatively (moving in the length direction of the rare earth magnet, the thickness direction of the rare earth magnet, or both). When the rare earth magnet is cut in this way, the slits restrict the shake of each cutting grindstone blade in the direction of the rotation axis, thereby enabling accurate cutting.

  Further, an air flow is generated around the cutting wheel blade that rotates at high speed. Since this flow exists so as to surround the outer peripheral edge (grinding wheel outer peripheral edge) of the cutting grindstone blade, when the grinding liquid is directly sprayed on the outer peripheral edge of the cutting grindstone blade, the grinding liquid comes into contact with this air flow. The grinding fluid scatters and the contact of the grinding fluid with the air layer is obstructed, so that efficient supply cannot be performed. On the other hand, when the outer periphery of the cutting grindstone blade is inserted into the slit of the grinding fluid supply nozzle as in the present invention, the grinding fluid supply nozzle is brought into contact with the grinding fluid within the grinding fluid supply nozzle. The flow of air is blocked by the main body (that is, the portion surrounding the slit), and the grinding fluid comes into contact with the outer peripheral portion of the cutting grindstone blade without being obstructed by the air layer.

  Accordingly, the grinding fluid that has reached each slit portion and has come into contact with the outer peripheral portion of each cutting grindstone blade is accompanied by the surface (outer peripheral surface and outer peripheral portion of the front and rear surfaces) of each rotating cutting grindstone blade. It moves to the grinding wheel outer peripheral blade side of each cutting grindstone blade by the centrifugal force of the rotation of the blade. Then, the grinding fluid moved to the grinding wheel outer peripheral blade side moves to each cutting point of the rare earth magnet with the rotation of the cutting wheel, and the grinding fluid is efficiently and reliably supplied to the cutting point. The amount of grinding fluid supplied can be reduced. It is also possible to effectively cool the processed part.

  Such a grinding fluid supply nozzle of the present invention is suitable as a grinding fluid supply nozzle in a rare earth magnet cutting processing apparatus.

  In multi-cutting processing of rare earth magnets, cutting is performed by supplying a grinding fluid to the cutting wheel, but the magnet fixing jig of the present invention is configured in pairs so that the rare earth magnet can be pressed and fixed in the cutting direction. It is preferable to use a magnet fixing jig. On one or both surfaces of these magnet fixing jigs, a plurality of guide grooves are formed so that the outer peripheral portions of the cutting grindstone blades can be inserted corresponding to the plurality of cutting grindstone blades.

  8 shows an example (figure (8 (a))) of the magnet fixing jig of the present invention, in which a base plate 31 on which the rare earth magnet m is placed is provided on the base 30. Magnet fixing jigs 31, 31 are provided on both ends in the length direction of the base plate 31. As shown in Fig. 8 (b), the magnet fixing jigs 31, 31 are The rare earth magnet m is configured to be fixed to the base body 30 in a state where the rare earth magnet m is pressed in the cutting direction (the length direction of the rare earth magnet). However, the number is not limited.) After the magnet fixing jigs 31 and 31 press the rare earth magnet m from both ends, the pressing state is maintained and the magnet fixing jigs 31 and 31 can be attached to and detached from the base body 30 with screws 31b. Note that in the case of FIG. Thus it is adapted to fix, is not limited thereto, it is also preferable to fix and pressed by air pressure or hydraulic pressure.

  On the surfaces of the magnet fixing jigs 31, a plurality of cutting wheel blades corresponding to the cutting wheel blades of the plurality of cutting wheel blades 1 (in this case, the number is 19 but the number is not limited). A guide groove 31a is formed.

  As will be described later, the outer periphery of each cutting grindstone blade is inserted into each guide groove 31a of the magnet fixing jig 31. Accordingly, the interval between the guide grooves 31a is set so as to correspond to the interval between the individual cutting grindstone blades of the multi-cutting grindstone blade described above, and is formed linearly in parallel with each other. The width between the guide grooves 31a is formed to be equal to or less than the thickness of the rare earth permanent magnet obtained by cutting.

  When supplying the grinding fluid using the magnet fixing jig and the above-described grinding fluid supply nozzle, the grinding fluid contacting the outer periphery of the cutting wheel blade in the grinding fluid supply nozzle is the surface (outer periphery) of the cutting wheel blade. Is moved into the guide groove of the magnet fixing jig and further moved to the rare earth magnet side to be supplied to the cutting point. Even when the above-described grinding fluid supply nozzle is used or when grinding is performed without using the above-described grinding fluid supply nozzle, for example, when the grinding fluid is directly injected to the cutting wheel blade, the grinding fluid is a guide. If it is allowed to flow into the groove, when the cutting wheel blade passes through the guide groove, the grinding liquid comes into contact with the outer periphery of the cutting wheel and is entrained on the surface (outer periphery) of the cutting wheel, thereby causing a rare earth magnet. By moving to the side, it can be supplied to the cutting point. Therefore, the width of the guide groove needs to be formed wider than the width of the cutting grindstone blade (that is, the width of the grindstone outer peripheral blade). If the width of the guide groove is too wide, the grinding liquid cannot be effectively supplied to the cutting wheel blade side. Therefore, the width of the guide groove of the magnet fixing jig is Wmm relative to the width W of the cutting wheel outer peripheral blade of the cutting wheel. And preferably (W + 0.1) mm or more and (W + 6) mm or less.

  On the other hand, the length of the guide groove (length in the cutting direction) is 1 mm or more, preferably 3 mm or more and preferably 100 mm or less from the rare earth magnet with the rare earth magnet fixed. When the length of the guide groove is less than 1 mm, the effect of guarding the dispersion of the grinding fluid when supplying the grinding fluid to the rare earth magnet that is to be cut or holding the grinding fluid is low. It is difficult to obtain sufficient strength for fixing and holding. Even if the length of the guide groove exceeds 100 mm, the effect of supplying the grinding fluid to the cutting part and the effect of improving the holding strength of the rare earth magnet will not be further improved. It is. Further, the depth of the guide groove is appropriately set according to the height of the rare earth permanent magnet, but it is preferably formed slightly deeper than the position of the lower surface of the rare earth permanent magnet to be fixed.

  In addition, the base plate 32 shown in FIG. 8 has a groove corresponding to the guide groove of the magnet fixing jig (in the case of FIG. 8, it is a groove having the same width as the guide groove), but is not limited thereto. This is a space when the outer peripheral end of the cutting wheel blade protrudes below the rare earth magnet in the final stage of cutting the rare earth magnet. It is preferable because an excessive load for cutting the base plate is not applied to the cutting wheel.

  The material of the magnet fixing jig is not particularly limited as long as it has a strength that is not inferior to the pinching force, but a high-strength engineering plastic or a metal-based material such as iron, stainless steel, or aluminum is preferable, especially space saving. When it is desired, it is better to use carbide or high strength ceramics.

  Note that the guide groove of the magnet fixing jig and the groove of the base plate can be formed in advance, but in the initial cycle of cutting the rare earth magnet, the rare earth magnet or the dummy workpiece is fixed. A rare earth magnet or a dummy workpiece may be cut, and at this time, a guide groove and a base plate groove may be formed by so-called co-cutting.

  Thus, using the magnet fixing jig as shown in FIG. 8 (a), and preferably the base plate, the rare earth magnet to be cut is removed by the magnet fixing jig as shown in FIG. 8 (b). While fixing the magnet fixing jig in the pressed state, the rare earth magnet is fixed by this, and the outer peripheral portion of each cutting grindstone blade 11 of the multi-cutting grindstone blade 1 is inserted into each guide groove of the magnet fixing jig Then, the grinding liquid is supplied to the multi-cutting grindstone blade using the above-mentioned grinding liquid supply nozzle, or the abrasive grains are made rare earth while rotating the cutting grindstone blade so that the grinding liquid flows into the guide groove. As shown in FIG. 8 (c), the grindstone of the cutting grindstone blade is moved in contact with the magnet and relatively moved (moved in the length direction of the rare earth magnet, the thickness direction of the rare earth magnet or both). Perimeter By cutting the rare earth magnet m, as shown in FIG. 8 (d), it is possible to cut the rare earth magnet m.

  When using the above-mentioned grinding fluid supply nozzle, it is preferable to use the grinding fluid supply nozzle slit and the guide groove of the magnet fixing jig in communication with each other. It is advantageous to supply the grinding fluid by entrainment to the surface of the cutting grindstone blade, while the distance between them is not too far, but if they are too close, the movement of the multi-cutting grindstone blade, the rare earth magnet, and the grinding fluid Since it may be a barrier for injection, discharge, etc., the distance between the slit of the grinding fluid supply nozzle and the guide groove of the magnet fixing jig is the distance between the grinding fluid supply nozzle and the upper surface of the magnet fixing jig at the end of cutting. It is preferable that the distance is 1 to 50 mm (for example, in the illustrated example, the grinding liquid supply nozzle is positioned 1 to 50 mm higher than the upper surface of the magnet fixing jig at the end of cutting). .

  In multi-cutting processing of rare earth magnets, rare earth magnets are conventionally cut and fixed by some method, and a rare earth magnet is conventionally removed on a substrate such as a carbon base using an adhesive that can be removed after cutting the rare earth magnet such as wax. A method of bonding and fixing the substrate and cutting is employed. However, this method requires steps of adhesion, peeling, and cleaning, which is very laborious. On the other hand, by using the magnet fixing jig of the present invention to sandwich and fix the rare earth magnet, the conventional steps of bonding, peeling, and cleaning can be omitted, and the labor can be saved. .

  In addition, when the multi-cutting grindstone blade, the magnet fixing jig, and the rare earth magnet are arranged in this way and the rare earth magnet is cut, the guide groove regulates the shake of each cutting grindstone blade in the rotation axis direction and has high accuracy. Cutting processing is possible.

  Furthermore, an air flow is generated around the cutting wheel blade that rotates at high speed. Since this flow exists so as to surround the outer peripheral edge (grinding wheel outer peripheral edge) of the cutting grindstone blade, when the grinding liquid is directly sprayed on the outer peripheral edge of the cutting grindstone blade, the grinding liquid comes into contact with this air flow. The grinding fluid scatters and the contact of the grinding fluid with the air layer is obstructed, so that efficient supply cannot be performed. On the other hand, as in the present invention, when the outer peripheral portion of the cutting grindstone blade is inserted into the guide groove of the magnet fixing jig, the air flow is blocked by the magnet fixing jig main body (that is, the portion surrounding the groove), The grinding fluid flowing into the guide groove comes into contact with the outer peripheral portion of the cutting grindstone blade without being obstructed by the air layer. If both the above-described grinding fluid supply nozzle and magnet fixing jig are used, the grinding fluid can be supplied to the cutting point particularly effectively and reliably by their synergistic action.

  Accordingly, the grinding fluid that has come into contact with the outer peripheral portion of each cutting wheel is accompanied by the surface of each rotating cutting blade blade (the outer peripheral surface and the outer peripheral portion of the front and back surfaces), and each is caused by the centrifugal force of rotation of the cutting wheel. The cutting grindstone blade moves to the grindstone outer peripheral blade side. Then, the grinding fluid moved to the grinding wheel outer peripheral blade side moves to each cutting point of the rare earth magnet with the rotation of the cutting wheel, and the grinding fluid is efficiently and reliably supplied to the cutting point. The amount of grinding fluid supplied can be reduced. It is also possible to effectively cool the processed part.

  Such a magnet fixing jig of the present invention is suitable as a magnet fixing jig in a rare earth magnet cutting apparatus.

  Furthermore, in the present invention, as shown in FIG. 9, cutting the rare earth magnet using the multi-cutting grindstone blade using both the grinding fluid supply nozzle and the magnet fixing jig described above, In particular, the cutting grindstone blade is guided more reliably and the grinding liquid is supplied along with the surface of the cutting grindstone blade in both the grinding liquid supply nozzle and the magnet fixing jig in the rotation direction of the cutting grindstone blade. It is more preferable because it can be continuously exhibited. In FIG. 9, the same reference numerals as those in FIGS. FIG. 9 shows a state in which the multi-cutting grindstone blade cuts one rare earth magnet. However, the present invention is not limited to this, and two or more rare earth magnets are arranged in parallel and / or in series. A plurality of rare earth magnets may be cut with one multi-cutting grindstone blade.

  Since the surface of the rare earth magnet that is to be cut is usually flat, the grinding fluid is supplied to this flat surface in the initial stage of grinding, but even if the grinding fluid is sprayed onto such a flat surface, The grinding fluid flows easily and cannot be effectively supplied to the cutting point. Therefore, at the initial stage of the rare earth magnet cutting (first cutting), either or both of the plurality of cutting wheel blades and rare earth magnets are placed in the longitudinal direction of the rare earth magnet in the cutting direction of the rare earth magnet (the length direction of the rare earth magnet). It is preferable to relatively move from one end to the other and cut the surface of the rare earth magnet to a predetermined depth over the entire length direction to form a cut groove in the rare earth magnet. In particular, when the above-described magnet fixing jig is used, cutting is performed with the outer periphery of each cutting grindstone blade inserted in each guide groove of the magnet fixing jig when cutting at both ends in the cutting direction. Is preferred.

  When the cutting groove is first formed in this way, the cutting groove formed by the first cutting functions as a guide for the cutting wheel blade in the next cutting, and the rotation of each cutting wheel blade in the rotational axis direction is regulated, and the accuracy A good cutting process is possible.

  In addition, when the cutting groove is first formed, the grinding fluid that has reached the surface of the workpiece of the rare earth magnet flows into the formed cutting groove. When the above-described grinding liquid supply nozzle is used, the grinding liquid supply nozzle Along with the grinding fluid moved along with the surface of each cutting grindstone blade from each slit portion, the grinding fluid flowing into each cutting groove is accompanied with the surface of each rotating grinding wheel blade, and the grinding fluid is As the cutting wheel blade rotates, the cutting tool moves to each cutting point of the rare earth magnet, and the grinding liquid is efficiently and reliably supplied to the cutting point. As a result, the supply amount of the grinding liquid can be reduced. . It is also possible to effectively cool the processed part.

  That is, compared with the case where the cutting grindstone blade continuously cuts the state of cutting a flat surface while cutting many parts of the rare earth magnet, if the cutting groove is formed first, the cutting groove is cut in the subsequent cutting, It will function as a supply path for effectively supplying the grinding liquid to the cutting point. Also, as the cutting wheel blade rotates, the grinding fluid is effectively discharged from the cutting point through the cutting groove to the downstream side in the rotation direction of the cutting wheel blade. A good grinding environment in which crushing of the grindstone and clogging are difficult to occur can be given efficiently through the cutting grooves.

  The depth of the cutting groove formed first (the depth of the first cutting by the movement of the rare earth magnet in the length direction) is preferably 0.1 mm or more and 20 mm or less, particularly 1 mm or more and 10 mm or less. When the depth of the cutting groove is less than 0.1 mm, the effect of preventing the scattering of the grinding fluid on the magnet surface is small, and the grinding fluid may not be effectively supplied to the cutting point. On the other hand, when the depth of the cutting groove exceeds 20 mm, the grinding itself for providing the cutting groove may result in processing with an insufficient supply of grinding fluid, which may prevent high-precision groove processing. .

  The width of the cutting groove is determined by the width of the cutting grindstone blade, but at the time of cutting, the width of the cutting grindstone blade is usually slightly larger than the width of the cutting grindstone blade (for example, the width of the cutting grindstone blade (the width of the outer peripheral blade of the grindstone) ) Exceeding 2 mm or less, preferably 1 mm or less.

  After forming the cutting groove, it is possible to cut the rare earth magnet by further cutting the rare earth magnet. For example, after forming the cutting groove, any of a plurality of cutting wheel blades and rare earth magnets on the side of the rare earth magnet Or both of them are moved relatively close to each other in the depth direction of the cutting groove of the rare earth magnet, and when using each cutting groove of the rare earth magnet and the above-described magnet fixing jig, With the outer peripheral portion of each cutting grindstone blade inserted into both the guide groove or the cutting groove and the guide groove, either one or both of the plurality of cutting grindstone blades and rare earth magnets are again set in the cutting direction (of the rare earth magnet). If the operation of cutting the rare earth magnet by moving relatively from one end to the other end of the rare earth magnet in the length direction) is repeated once or twice or more, It is possible to cut the entire direction is. At this time, the moving distance in the depth direction of the cutting groove (cutting depth after movement) is preferably 0.1 mm or more and 20 mm or less, particularly preferably 1 mm or more and 10 mm or less.

  Moreover, it is possible to make the rotation speed of the cutting grindstone blade when forming the cutting groove different from the rotation speed of the cutting grindstone blade when cutting the rare earth magnet thereafter. Moreover, it is also possible to make the moving speed of the cutting grindstone blade when forming the cutting groove different from the moving speed of the cutting grindstone blade when cutting the rare earth magnet thereafter.

  Further, the cutting stress along the moving direction at the time of cutting by the movement of the rare earth magnet in the length direction of the cutting groove (at the time of cutting of forming the cutting groove, at the time of subsequent cutting, or both) is cut. The rare earth magnet is preferably applied in a direction opposite to the moving direction of the plurality of cutting wheel blades relative to the rare earth magnet.

  That is, the direction in which the multi-cutting grindstone blade moves relative to the rare-earth magnet that is the workpiece (relative means that the multi-cutting grindstone blade may move even if the rare-earth magnet moves). It is preferable to perform cutting so that the reverse force is applied to the rare earth magnet from the cutting wheel. The reason for this is that when the cutting wheel blade receives a force in the direction of traveling relative to the rare earth magnet, the cutting wheel blade receives a drag force from the rare earth magnet, so that a compressive stress is applied to the cutting wheel blade. When compressive stress is applied to the cutting grindstone blade, the cutting grindstone blade is bent, causing deterioration in processing accuracy and so-called slipping that the base plate of the cutting grindstone blade comes into contact with the rare earth magnet being cut. In this case, not only the processing accuracy is lowered, but also the temperature becomes high due to the friction, the rare earth magnet becomes defective, and the cutting wheel blade cannot be used.

  If the force applied from the cutting wheel blade to the rare earth magnet is in the direction opposite to the traveling direction of the multi-cutting wheel blade, the cutting wheel blade will not be subjected to compressive stress, which will prevent drumming and increase processing accuracy. it can. Moreover, since no compressive force is applied between the cutting wheel blade and the rare earth magnet, the machined sludge is effectively discharged by the grinding liquid, and the cutting wheel blade is maintained in sharpness.

  In order to exert a force opposite to the traveling direction of the multi-cutting wheel, the peripheral speed and cutting area (cutting height x width of the cutting wheel) of the cutting wheel and the moving speed of the multi-cutting wheel are greatly affected. come. When the peripheral speed is high, a force opposite to the traveling direction of the blade is generated due to the frictional resistance between the rotating blade tip and the magnet. However, in the traveling direction, a stress is generated in the traveling direction by the multi-cutting grindstone blade traveling, and the product of this force and the cutting area becomes a force in the traveling direction. Among these, it is necessary that the stress in the anti-advance direction due to the rotational force of the cutting grindstone blade be greater than the stress due to the advancement of the cutting grindstone blade.

  In order to satisfy this condition, for example, the peripheral speed of the cutting grindstone blade is preferably set to 20 m / sec or more. In order to reduce the cutting area, the width of the cutting grindstone blade (width of the grindstone cutting blade) is preferably 1.5 mm or less. Moreover, when this width is thinner than 0.1 mm, the cutting area can be reduced, but the strength of the blade is lowered, and the dimensional accuracy may be lowered. Therefore, the width of the cutting grindstone blade (width of the grindstone cutting blade) is 0.1 to 1.5 mm is preferable. On the other hand, the cutting height is preferably 20 mm or less, and the feeding speed (advance speed) of the cutting grindstone blade is preferably 3000 mm / min or less, particularly preferably 50 to 2000 mm / min. The rotation direction of the multi-cutting grindstone blade at the cutting point and the moving direction (traveling direction) of the multi-cutting grindstone blade may be the same or opposite directions.

  In the present invention, a rare earth magnet is suitably cut, and the rare earth magnet (rare earth sintered magnet) that is the object to be cut is not particularly limited. (R is at least one of rare earth elements including Y, and the same applies hereinafter) and can be suitably applied to cutting rare earth magnets (rare earth sintered magnets).

  As R-Fe-B rare earth sintered magnets, those containing 5-40% R, 50-90% Fe, 0.2-8% B in mass percentages, magnetic properties and corrosion resistance. To improve, such as C, Al, Si, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ag, Sn, Hf, Ta, W, etc. What contains 1 or more types of an additional element is suitable. The addition amount of these additive elements is usually 30% by mass or less in the case of Co and 8% by mass or less in the case of other elements. If additional elements are added, the magnetic properties are deteriorated.

  The R-Fe-B rare earth sintered magnet is obtained by, for example, weighing a raw metal, melting and casting, and finely pulverizing the obtained alloy to an average particle diameter of 1 to 20 μm. It is possible to obtain a magnet powder, then mold in a magnetic field, then sinter at 1000 to 1200 ° C. for 0.5 to 5 hours, and further heat-treat at 400 to 1000 ° C. for production.

  Hereinafter, although an experiment example and a comparative experiment example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following example.

[Experimental Example 1]
Diamond abrasive grains are fixed to the outer peripheral edge of a 120 mmφ × 40 mmφ × 0.5 mmt donut disk-shaped base plate made of SKD (tool alloy JIS) by artificial bonding with an average particle diameter of 150 μm in volume content. This was used as a grindstone portion (grinding wheel outer peripheral blade) to produce an outer peripheral cutting blade (cutting grindstone blade). The protrusion of the grindstone part from the base plate was 0.05 mm on one side, that is, the width of the grindstone part (width in the thickness direction of the base plate) was 0.6 mm.

  Using this outer peripheral cutting blade, a cutting test was performed using an Nd-Fe-B rare earth sintered magnet as an object to be cut. The cutting test was performed under the following conditions. A multi-cutting grindstone blade was formed by assembling 39 peripheral cutting blades at 2.1 mm intervals with a spacer in between. The spacer used was 80 mmφ × 40 mmφ × 2.1 mmt. This is a setting in which the thickness of the rare earth magnet after cutting is set to 2.0 mmt.

  A multi-cutting grindstone blade assembled with 39 outer peripheral cutting blades and 38 spacers is inserted into the slit of the grinding fluid supply nozzle shown in FIGS. Inserted as indicated. Each slit of the grinding liquid supply nozzle had a thickness of 2.5 mm and a width of 0.7 mm, and was set so that the cutting blade was positioned at the center of the slit.

  Further, the Nd—Fe—B rare earth sintered magnet, which is an object to be cut, was processed into a length of 100 mm, a width of 30 mm, and a height of 17 mm using a double-ended polishing machine with an accuracy of ± 0.05 mm. A number of products with a thickness of 2.0 mm are taken at a time by cutting with an outer peripheral cutting blade in the length direction. In this case, 38 pieces are obtained by obtaining 38 pieces excluding two pieces at both ends from one magnet block.

  Nd-Fe-B rare earth sintered magnets have a length of 30 mm at both ends in the cutting direction, a width of 0.9 mm, and a thickness (depth direction) of 19 mm, and the same number at the position corresponding to each outer peripheral cutting blade ( That is, the cutting position and the guide groove were combined and fixed as shown in FIG. 8B by a magnet fixing jig having 39 guide grooves. In this case, the upper surface of the magnet fixing jig (the surface on the side of the multi-cutting grindstone blade) and the height of the upper surface of the Nd—Fe—B rare earth sintered magnet (the surface on the side of the multi-cutting grindstone blade) that is the object to be cut. It was the same.

The cutting operation was as follows.
The grinding fluid used was 30 L / min. First, the multi-cutting grindstone blade is lowered to the Nd-Fe-B rare earth sintered magnet side on one magnet fixing jig holding the Nd-Fe-B rare earth sintered magnet, and each outer cutting blade Is inserted into each guide groove 2 mm from the outer periphery, the multi-cutting grindstone blade is rotated at 7,000 rpm, and the grinding fluid is supplied from the grinding fluid supply nozzle, while the other magnet fixing jig side is rotated at a speed of 100 mm / min. Further, without changing the height of the multi-cutting grindstone blade, it is returned to the one magnet fixing jig side and cut into the Nd-Fe-B rare earth sintered magnet (depth 2 mm). ) Was formed.

  Next, on the one magnet fixing jig, the multi-cutting wheel is lowered 16 mm toward the Nd-Fe-B rare earth sintered magnet, and the multi-cutting wheel is rotated at 7,000 rpm to grind the grinding fluid. While supplying from the liquid supply nozzle, it is moved to the other magnet fixing jig side at a speed of 20 mm / min for cutting, and further, the one magnet fixing jig side is changed without changing the height of the multi-cutting grindstone blade. Returned to.

  The rare earth magnet cut using the outer peripheral blade in Experimental Example 1 was measured if the thickness of the central part between the cut surfaces was measured with a micrometer, and the cut size control width was 2.0 ± 0.05 mm. When the dimensions were out of alignment, the thickness of the spacer was adjusted, and the multi-cutting grindstone blade was corrected so as to be within the control width. Furthermore, when the spacer adjustment was performed three or more times at the same position of the outer peripheral cutting blade, it was determined that the outer peripheral cutting blade was not stable, and was replaced with a new outer peripheral cutting blade. Under such conditions, the Nd—Fe—B rare earth sintered magnet 1000 block was cut. Table 1 shows the evaluation results of the cut state.

[Comparative Experiment Example 1]
Except for the following changes, the Nd—Fe—B rare earth sintered magnet 1,000 block was cut in the same manner as in Experimental Example 1. Table 1 shows the evaluation results of the cut state.

The grinding fluid supply nozzle is changed to one having only one opening without slit (height 3 mm, width 100 mm (opening area 300 mm ² )), and the grinding fluid is supplied from the outside of the multi-cutting grinding blade to the grinding fluid supply nozzle. It sprayed from the opening.

  In addition, the Nd—Fe—B rare earth sintered magnet as the object to be cut was fixed to the carbon base plate by adhesion with wax, and no magnet fixing jig was used.

The cutting operation was as follows.
The grinding fluid used was 30 L / min. First, the multi-cut grinding wheel blade is outside one end in the cutting direction of the Nd—Fe—B rare earth sintered magnet, and the lower end of each outer cutting blade is 18 mm below the upper surface of the Nd—Fe—B rare earth sintered magnet. Is lowered to the Nd-Fe-B rare earth sintered magnet side so that the height becomes 20 mm / min while rotating the multi-cutting grindstone blade at 7,000 rpm and supplying the grinding fluid from the grinding fluid supply nozzle. Then, the workpiece was cut by moving it to the outside on the other end side in the cutting direction, and returned to the outside on the one end side without changing the height of the multi-cutting grindstone blade.

  As is clear from Table 1, the multi-cutting method of the present invention stabilizes the dimensional accuracy for a long time even if the blade thickness is thin, and can reduce the adjustment of the spacer thickness, replacement of the outer cutting blade, etc. It was confirmed that the improvement of the property can be achieved.

[Experiment 2]
Diamond abrasive grains are fixed to the outer peripheral edge of a 120 mmφ × 40 mmφ × 0.35 mmt donut disc-shaped base plate made of cemented carbide (WC-90 mass% / Co-10 mass%) (average) An artificial diamond having a particle size of 150 μm was contained in a volume content of 25%), and this was used as a grindstone part (grinding wheel outer peripheral blade) to produce an outer peripheral cutting blade (cutting grindstone blade). The protrusion of the grindstone part from the base plate was 0.05 mm on one side, that is, the width of the grindstone part (width in the thickness direction of the base plate) was 0.45 mm.

  Using this outer peripheral cutting blade, a cutting test was performed using an Nd-Fe-B rare earth sintered magnet as an object to be cut. The cutting test was performed under the following conditions. 41 peripheral cutting blades were assembled at intervals of 2.1 mm with a pacer interposed therebetween to form a multi-cutting grindstone blade. The spacer used was 80 mmφ × 40 mmφ × 2.1 mmt. This is a setting in which the thickness of the rare earth magnet after cutting is set to 2.0 mmt.

  A multi-cutting grindstone blade assembled with 41 outer cutting blades and 40 spacers is inserted into the slit of the grinding fluid supply nozzle shown in FIGS. Inserted as indicated. Each slit of the grinding fluid supply nozzle had a thickness of 2.5 mm and a width of 0.6 mm, and was set so that the cutting blade was positioned at the center of the slit.

  Further, the Nd—Fe—B rare earth sintered magnet, which is an object to be cut, was processed into a length of 100 mm, a width of 30 mm, and a height of 17 mm using a double-ended polishing machine with an accuracy of ± 0.05 mm. Cut with a peripheral cutting blade in the length direction, and take a large number of 2.0 mm thick products at a time. In this case, 40 pieces are obtained to obtain 40 pieces excluding 2 pieces at both ends from one magnet block.

  Nd-Fe-B rare earth sintered magnets have a length of 30 mm at both ends in the cutting direction, a width of 0.9 mm, and a thickness (depth direction) of 19 mm, and the same number at the position corresponding to each outer peripheral cutting blade ( That is, the cutting position and the guide groove were combined and fixed as shown in FIG. 8B by a magnet fixing jig having 41 guide grooves. In this case, the upper surface of the magnet fixing jig (the surface on the side of the multi-cutting grindstone blade) and the height of the upper surface of the Nd—Fe—B rare earth sintered magnet (the surface on the side of the multi-cutting grindstone blade) that is the object to be cut. It was the same.

The cutting operation was as follows.
The grinding fluid used was 30 L / min. First, the multi-cutting grindstone blade is lowered to the Nd-Fe-B rare earth sintered magnet side on one magnet fixing jig holding the Nd-Fe-B rare earth sintered magnet, and each outer cutting blade Is inserted into each guide groove 2 mm from the outer periphery, the multi-cutting grindstone blade is rotated at 7,000 rpm, and the grinding fluid is supplied from the grinding fluid supply nozzle, while the other magnet fixing jig side is rotated at a speed of 100 mm / min. Further, without changing the height of the multi-cutting grindstone blade, it is returned to the one magnet fixing jig side and cut into the Nd-Fe-B rare earth sintered magnet (depth 2 mm). ) Was formed.

  Next, on the one magnet fixing jig, the multi-cutting wheel is lowered 16 mm toward the Nd-Fe-B rare earth sintered magnet, and the multi-cutting wheel is rotated at 7,000 rpm to grind the grinding fluid. While supplying from the liquid supply nozzle, it is moved to the other magnet fixing jig side at a speed of 20 mm / min for cutting, and further, the one magnet fixing jig side is changed without changing the height of the multi-cutting grindstone blade. Returned to.

  The rare earth magnet cut using the produced outer peripheral blade was measured with a micrometer for the thickness of the central part between the cut surfaces, and it was considered acceptable if it was 2.0 ± 0.05 mm as the cut dimension control width. When it came off, the spacer thickness was adjusted, and the multi-cutting grindstone blade was corrected so as to be within the control width. Furthermore, when the spacer adjustment was performed three or more times at the same position of the outer peripheral cutting blade, it was determined that the outer peripheral cutting blade was not stable, and was replaced with a new outer peripheral cutting blade. Under such conditions, the Nd—Fe—B rare earth sintered magnet 1000 block was cut. Table 2 shows the evaluation results of the cut state.

  As is clear from Table 2, the multi-cutting method of the present invention stabilizes the dimensional accuracy over a long period even when using a thin-blade carbide wheel with a carbide base plate, adjusting the spacer thickness, and outer peripheral cutting blade. It was found that the number of replacements can be reduced, productivity can be improved, and the number of products can be further improved.

[Experiment 3]
Diamond abrasive grains are fixed to the outer peripheral edge of a 130 mmφ × 40 mmφ × 0.5 mmt doughnut-shaped base plate made of cemented carbide (WC-90% by mass / Co-10% by mass) (average) An artificial diamond having a particle size of 150 μm was contained in a volume content of 25%), and this was used as a grindstone part (grinding wheel outer peripheral blade) to produce an outer peripheral cutting blade (cutting grindstone blade). The protrusion of the grindstone part from the base plate was 0.05 mm on one side, that is, the width of the grindstone part (width in the thickness direction of the base plate) was 0.6 mm.

  Using this outer peripheral cutting blade, a cutting test was performed using an Nd-Fe-B rare earth sintered magnet as an object to be cut. The cutting test was performed under the following conditions. Fourteen peripheral cutting blades were assembled at intervals of 3.1 mm with a pacer interposed therebetween to form a multi-cutting grindstone blade. The spacer used was 70 mmφ × 40 mmφ × 3.1 mmt. This is a setting in which the thickness of the rare earth magnet after cutting is set to 3.0 mmt.

  A multi-cutting grindstone blade assembled with 14 outer cutting blades and 13 spacers is inserted into the slit of the grinding fluid supply nozzle shown in FIGS. Inserted as indicated. Each slit of the grinding fluid supply nozzle had a thickness of 2.5 mm and a width of 0.8 mm, and was set so that the cutting blade was positioned at the center of the slit.

  Further, the Nd—Fe—B rare earth sintered magnet that is the object to be cut was one that had been processed to a precision of ± 0.05 mm using a double-ended grinder with a length of 47 mm × width of 30 mm × height of 20 mm. A number of products having a thickness of 3.0 mm are taken at a time by cutting with an outer peripheral cutting blade in the length direction. In this case, 13 pieces are obtained from a magnet 1 block except for two pieces at both ends.

  The Nd-Fe-B rare earth sintered magnets are 50 mm long, 0.8 mm wide and 22 mm thick (depth direction) at both ends in the cutting direction, and the same number of positions corresponding to each outer cutting blade ( That is, the cutting position and the guide groove were combined and fixed as shown in FIG. 8B by a magnet fixing jig having 14) guide grooves. In this case, the upper surface of the magnet fixing jig (the surface on the side of the multi-cutting grindstone blade) and the height of the upper surface of the Nd—Fe—B rare earth sintered magnet (the surface on the side of the multi-cutting grindstone blade) that is the object to be cut. It was the same.

The cutting operation was as follows.
The grinding fluid used was 30 L / min. First, the multi-cutting grindstone blade is lowered to the Nd-Fe-B rare earth sintered magnet side on one magnet fixing jig holding the Nd-Fe-B rare earth sintered magnet, and each outer cutting blade Is inserted into each guide groove 7 mm from the outer periphery, the multi-cutting grindstone blade is rotated at 9,000 rpm (61 m / sec), and the other liquid is supplied at a speed of 70 mm / min while supplying the grinding liquid from the grinding liquid supply nozzle. Move to the magnet fixing jig side and cut, and then return to the one magnet fixing jig side without changing the height of the multi-cutting grindstone blade and cut into Nd-Fe-B rare earth sintered magnets A groove (depth 7 mm) was formed.

  Next, on the one magnet fixing jig, the multi-cutting grindstone blade is lowered by 14 mm toward the Nd-Fe-B rare earth sintered magnet, and the multi-cutting grindstone blade is rotated at 9,000 rpm to grind the grinding fluid. While supplying from the liquid supply nozzle, it is moved to the other magnet fixing jig side at a speed of 20 mm / min for cutting, and further, the one magnet fixing jig side is changed without changing the height of the multi-cutting grindstone blade. Returned to.

  When cutting the Nd—Fe—B rare earth sintered magnet, a thin cutting dynamometer 9254 made by Kistler was installed under the Nd—Fe—B rare earth sintered magnet, and the stress received by the magnet was measured. The stress along the moving direction of the multi-cutting wheel at the time of cutting in which the first guide groove is formed is 75 N in the moving direction of the cutting whetstone blade, and the stress along the moving direction of the multi-cutting wheel at the next cutting is 140 N in the direction of travel of the cutting wheel.

  For the rare earth magnet cut using the produced outer peripheral blade, the thicknesses at the five corners and the central part between the cut surfaces as shown in FIG. The difference was obtained. The results are shown in FIG.

[Experimental Example 4]
Except for the following changes, the Nd—Fe—B rare earth sintered magnet was cut in the same manner as in Experimental Example 3.

The cutting operation was as follows.
The grinding fluid used was 30 L / min. First, the multi-cutting grindstone blade is lowered to the Nd-Fe-B rare earth sintered magnet side on one magnet fixing jig holding the Nd-Fe-B rare earth sintered magnet, and each outer cutting blade Is inserted into each guide groove of 0.75 mm from the outer periphery, the multi-cutting grindstone blade is rotated at 9,000 rpm (61 m / sec), and the grinding fluid is supplied from the grinding fluid supply nozzle at a speed of 1500 mm / min. The Nd-Fe-B rare earth sintered magnet is moved to the other magnet fixing jig side and cut, and further returned to the one magnet fixing jig side without changing the height of the multi-cutting grindstone blade. A cutting groove (depth 0.75 mm) was formed in

  Next, on the one magnet fixing jig, the multi-cutting grindstone blade is lowered by 0.75 mm toward the Nd-Fe-B rare earth sintered magnet side, and the multi-cutting grindstone blade is rotated at 9,000 rpm to obtain a grinding liquid. Is supplied from the grinding fluid supply nozzle and moved to the other magnet fixing jig side at a speed of 1500 mm / min for cutting, and the above-mentioned one magnet fixing treatment is performed without changing the height of the multi-cutting grindstone blade. Returned to the instrument side. This descent and movement (cutting) was repeated 26 cycles to cut the Nd—Fe—B rare earth sintered magnet.

  When cutting the Nd—Fe—B rare earth sintered magnet, a thin cutting dynamometer 9254 made by Kistler was installed under the Nd—Fe—B rare earth sintered magnet, and the stress received by the magnet was measured. The results are shown in FIG. (Note that in FIG. 11 (a), the stress along the moving direction of the multi-cutting grindstone blade and the stress in the vertical direction perpendicular to this direction and the rotational axis direction of the cutting grindstone blade are also shown.) Both the stress along the direction of movement of the multi-cutting wheel during cutting with the guide groove and the stress along the direction of movement of the multi-cutting wheel during subsequent cutting are opposite to the direction of travel of the cutting wheel 100N.

  For the rare earth magnet cut using the produced outer peripheral blade, the thicknesses at the five corners and the central part between the cut surfaces as shown in FIG. The difference was obtained. The results are shown in FIG.

[Comparative Experiment Example 2]
Except for the following changes, the Nd—Fe—B rare earth sintered magnet was cut in the same manner as in Experimental Example 3.

Change the grinding fluid supply nozzle to one that has only one opening (3 mm in height and 50 mm in width (opening area 150 mm ² )) without slits, and remove the grinding fluid from the outside of the multi-cutting grinding wheel. It sprayed from the opening.

  In addition, the Nd—Fe—B rare earth sintered magnet as the object to be cut was fixed to the carbon base plate by adhesion with wax, and no magnet fixing jig was used.

The cutting operation was as follows.
The grinding fluid used was 30 L / min. First, the multi-cut grinding wheel blade is outside one end in the cutting direction of the Nd—Fe—B rare earth sintered magnet, and the lower end of each outer cutting blade is 21 mm below the upper surface of the Nd—Fe—B rare earth sintered magnet. Is lowered to the Nd-Fe-B rare earth sintered magnet side so that the height becomes 20 mm / min while rotating the multi-cutting grindstone blade at 9,000 rpm and supplying the grinding fluid from the grinding fluid supply nozzle. Then, the workpiece was cut by moving it to the outside on the other end side in the cutting direction, and returned to the outside on the one end side without changing the height of the multi-cutting grindstone blade.

  When cutting the Nd—Fe—B rare earth sintered magnet, a thin cutting dynamometer 9254 made by Kistler was installed under the Nd—Fe—B rare earth sintered magnet, and the stress received by the magnet was measured. The result is shown in FIG. 11 (b) (in FIG. 11 (b), the stress along the moving direction of the multi-cutting grindstone blade, the vertical direction perpendicular to this direction, and the stress in the rotation axis direction of the cutting grindstone blade) Is also written.) The stress along the moving direction of the multi-cutting wheel at the time of cutting was 190 N in the traveling direction of the cutting wheel.

  For the rare earth magnet cut using the produced outer peripheral blade, the thicknesses at the five corners and the central part between the cut surfaces as shown in FIG. The difference was obtained. The results are shown in FIG.

  As is clear from FIG. 10, it can be seen that the cutting accuracy is remarkably improved by cutting by the multi-cutting method of the present invention. Further, it can be seen that the accuracy can be further improved by cutting so that the stress is applied in the direction opposite to the moving direction of the multi-cutting grindstone blade.

It is a conceptual diagram explaining the change of the shape in press molding, sintering, heat processing, and a process of manufacture of a rare earth magnet. It is a perspective view which shows an example of the multi-cutting grindstone blade used for this invention. It is a figure which shows an example of the grinding fluid supply nozzle used for this invention, (a) is a perspective view, (b) is a top view, (c) is a front view, (d) is an expansion of the X section of (a). FIG. It is another figure which shows the grinding fluid supply nozzle of FIG. 4, (a) is a top view, (b) is sectional drawing along the BB line in (a), (c) is in (a). Sectional drawing along CC line, (d) is sectional drawing along DD line in (a). It is a figure which shows another example of the grinding fluid supply nozzle used for this invention, (a) is a perspective view, (b) is a top view, (c) is a front view, (c) is a side view. It is a perspective view which shows the state which inserted the multi-cutting grindstone blade of FIG. 2 in the slit of the grinding fluid supply nozzle of an example used for this invention. It is a perspective view which shows the state which cut | disconnects a rare earth magnet using the multi-cutting grindstone blade and grinding fluid supply nozzle which were shown in FIG. It is a perspective view explaining the process in which a rare earth magnet is cut | disconnected using the magnet fixing jig of an example of this invention. It is a figure which shows the state which cut | disconnects a rare earth magnet using an example multi-cutting grindstone blade of this invention, an example grinding fluid supply nozzle, and an example magnet fixing jig, (a) is a perspective view, (b) is a top view. (C) is a side view, (d) is a front view. It is a graph which shows the precision of the thickness of the cut magnet in Experimental example 3, 4 and Comparative experimental example 2. FIG. It is a graph which shows the measurement result of the cutting stress in Experimental example 4 and Comparative experimental example 2. FIG.

Explanation of symbols

1 Multi cutting wheel blade (Multi cutting blade)
11 Cutting wheel (outer blade)
11a Grinding wheel peripheral edge (abrasive part)
11b Base plate 12 Rotating shaft (shaft)
2 Grinding liquid supply nozzle 2a Grinding liquid supply nozzle body 2b Introduction flow path 21 Slit 21a Slit forming part 22 Grinding liquid introduction port 23 Flow path (Liquid pool)
30 Base 31 Magnet Fixing Fixture 31a Guide Groove 31b Screw 31b
32 Base plate m Rare earth magnet 101 Molded product 102 Sintered / heat treated product 103 Processed product (product)

Claims (4)

Cutting a rare earth magnet formed by arranging a plurality of cutting wheel blades having a grinding wheel outer peripheral edge at the outer peripheral edge of a thin disk or thin donut disk base plate at a predetermined interval along the axial direction of the rotating shaft. A magnet fixing jig for fixing the rare earth magnet when cutting the rare earth magnet with a multi-cutting grindstone blade for
A pair of rare earth magnets can be pressed and fixed in the cutting direction, and a plurality of guide grooves corresponding to each cutting wheel blade can be inserted into one or both surfaces of each pair of cutting wheel blades. A magnet fixing jig, characterized in that it is formed.   2. The magnet fixing jig according to claim 1, wherein the guide groove of the magnet fixing jig is formed with a length from the rare earth magnet in a state where the rare earth magnet is fixed to 1 mm or more and 100 mm or less.   The width of the guide groove of the magnet fixing jig is greater than Wmm and equal to or less than (W + 6) mm with respect to the width W of the grinding wheel outer peripheral blade of the cutting grindstone blade. Magnet fixing jig.   A rare earth magnet cutting apparatus comprising the magnet fixing jig according to any one of claims 1 to 3.

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