CN1228799C - Ring shaped magnetic shaping device and its used metal mould and ring shaped magnet shaping method - Google Patents
Ring shaped magnetic shaping device and its used metal mould and ring shaped magnet shaping method Download PDFInfo
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- CN1228799C CN1228799C CN 02101737 CN02101737A CN1228799C CN 1228799 C CN1228799 C CN 1228799C CN 02101737 CN02101737 CN 02101737 CN 02101737 A CN02101737 A CN 02101737A CN 1228799 C CN1228799 C CN 1228799C
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Abstract
The present invention relates to the ring-shaped magnet forming device which comprises a die having a through hole, a core for forming a ring-like cavity in the through hole, a feeder box which is moved along a surface of the die, and feeds the powder in the cavity by rubbing, and upper and lower punches to press the powder filled in the cavity in order to obtain the ring-like magnet. An inclined surface inclined in the level direction is formed on a tip surface of the upper punch so that the space between tip surfaces of the upper and lower punches is larger on the back side than that on the front side of the cavity. Alternatively, the inclined surface inclined in the rubbing direction may be formed on the surface of the die and the core, and on the tip surface of the lower punch so that the depth on the back side is smaller than that on the front side of the cavity.
Description
Technical field
The present invention relates to ring-like magnet forming apparatus and used metal die and ring-like magnet forming method thereof.Specifically, relate to the ring-like magnet forming apparatus that is used for the moulding of ring shape binding magnet and used metal die and ring-like magnet forming method thereof, this ring shape binding magnet is to obtain from the rare earth alloy powder that is coated by resin adhesive.
Background technology
In recent years, along with the rotation high speed of Spindle Motor used in disk, the CD, require to improve the spin balancing of the used annular magnet of Spindle Motor.
In order to obtain the annular magnet motor, when adopting former with ring-like magnet forming apparatus that core rod separates, if the powder that is filled in the die cavity is inhomogeneous, then when last low punch compaction of powders, core rod generation inclination.If compaction of powders under this state, then each position thickness difference (in uneven thickness) of the annular magnet of moulding.
When such magnet was used for Spindle Motor, the spin balancing of annular magnet was poor.When making the Spindle Motor high speed rotating, even each position thickness difference a little, the spin balancing of annular magnet is also destroyed, makes axiality become big.
For this reason, Japanese kokai publication hei 9-241703 number a kind of scheme has been proposed, wherein, the upper end that one is located at mandrel lower end on the core and transmitter shaft is by ball-and-socket joint and combination, simultaneously under the bound fraction of ball-and-socket joint, have under the state that is positioned a right angle orientation, with the movement guide device of transmitter shaft to its axis direction guiding.In addition, the part of core combination with ball-and-socket joint is the center, freely tilts to move with respect to transmitter shaft, can suppress the in uneven thickness of the core shift of core and product thus well.
But because mandrel extends, core is eccentric easily in the prior art.Therefore, the off-centre of the annular magnet that obtains strengthens and causes axiality to worsen, and rate of finished products is low, and productivity is poor.
Summary of the invention
Main purpose of the present invention provides a kind of axiality, raising rate of finished products and productive ring-like magnet forming apparatus and used metal die and ring-like magnet forming method thereof that reduces annular magnet.
Ring-like magnet forming apparatus provided by the invention possesses the former of coherent through hole; In above-mentioned through hole, the core rod that is fixed as one with former in order to form annular die cavity; And the powder of a pair of squeeze pack in die cavity is to obtain the drift of annular magnet.
Metal die provided by the invention is used for the moulding annular magnet, possesses the former of coherent through hole; And in through hole, the core rod that is fixed as one with former in order to form annular die cavity.
In the present invention,, make core rod not eccentric, make that the position relation of former and core rod is more stable with respect to former by former and core rod are fixed into one.Therefore, the little high-quality annular magnet of axiality can be obtained, the rate of finished products and the productivity of annular magnet can be improved.
Preferably comprise the centering machine structure of regulating core rod, so that obtain required die cavity.At this moment, by regulating core rod, can suppress the axiality of annular magnet more.
In addition, preferred die cavity forms annular.When die cavity forms annular, though the axiality of the annular magnet that core rod is easily eccentric, obtain is big, but, in the present invention because the position of former and core rod relation is stable, core rod is not eccentric with respect to former, so, even when die cavity formed annular, also can suppress axiality, obtain required circular ring magnet.
In addition, ring-like magnet forming apparatus provided by the invention possesses the former of coherent through hole; In through hole, the core rod that is provided with in order to form annular die cavity; Along female mold surfaces move, with powder scrape give with smearing in the die cavity powder to the powder device; And the powder that is filled in the die cavity pushed so that obtain the upper punch and the low punch of annular magnet, on the surface of above-mentioned former and core rod and at least a portion of at least one side in the low punch front end face, have towards scraping and smear the inclined plane that direction tilts, make that the depth ratio front side of rear side is shallow in the die cavity.
In addition, ring-like magnet forming method provided by the invention is, powder is scraped in the annular die cavity that is filled to former with through hole and core rod formation with smearing, to above-mentioned powder extrusion forming is annular magnet, when giving powder, under the shallow state of the rear side depth ratio front side of die cavity, powder scraped with smearing supply in the die cavity.
Among the present invention, inhomogeneous at scraping the formula of smearing to the filling that powder causes, at least one side's of the top of former and core rod and low punch front end face a part is tilted, make the rear side depth ratio front side of die cavity shallow.Like this, even scrape the formula of smearing when giving powder, also can make in the die cavity powder filling amount of each position, especially rear side and front side even substantially, or make the charging quantity of front side more.So, when the powder in the die cavity is pressurizeed, in die cavity, can reduce the powder compacting pressure differential at each position.So, can suppress the off-centre of core rod with respect to former, obtain reducing the even annular magnet of moulding density unevenness.Therefore, the axiality of annular magnet is little, can improve rate of finished products and productivity.
In addition, ring-like magnet forming apparatus provided by the invention possesses the former of coherent through hole; The core rod that in through hole, is provided with in order to form annular die cavity; Along female mold surfaces move, with powder scrape give with smearing in the die cavity powder to the powder device; And the powder that is filled in the die cavity pushed so that obtain the upper punch and the low punch of annular magnet, on at least a portion of upper punch front end face, have towards scraping and smear the inclined plane that direction tilts, make to be that the die cavity rear side is bigger than front side at interval between upper punch and the low punch front end face.
In addition, ring-like magnet forming method provided by the invention is, powder is scraped in the annular die cavity that is filled to former with through hole and core rod formation with smearing, with a pair of drift powder is pressurizeed, be shaped to annular magnet, the rear side that the front end face of a pair of drift during moulding is spaced apart die cavity is bigger than front side.
In the present invention, inhomogeneous at scraping the formula of smearing to the filling that powder causes, at least a portion of upper punch is tilted, the interval during moulding between the front end face of upper punch and low punch with respect to powder device approach axis, is that the die cavity rear side is bigger than front side.Therefore, smear to powder by scraping, with respect to approach axis to the powder device, although the rear side of die cavity is bigger than the packing density of front side, but during owing to compaction of powders in die cavity, the volume of die cavity is that rear side is bigger than front side, so, in die cavity, can lower the powder compacting pressure differential between each position.Therefore, can suppress the off-centre of core rod with respect to former, the compact density of the annular magnet that obtains is inhomogeneous less.As a result, the axiality of annular magnet is little, can improve rate of finished products and productivity.
Preferred former and core rod are fixed as one by plate.At this moment, can firmly fix core rod, so, suppress the biasing of core rod in through hole more, further reduce the axiality of annular magnet.
In addition, the largest interval between the front end face of the difference of height on inclined plane, the depth difference of die cavity or a pair of drift is poor, is preferably more than the 0.01mm, below the 0.15mm.At this moment, it is inhomogeneous to offset the filling that is filled in the powder in the die cavity.Therefore, the compact density of the annular magnet that obtains is inhomogeneous less, can obtain the little high-quality annular magnet of axiality.
It is especially effective when the binding magnet that the present invention coats rare earth alloy powder with resin adhesive in compacting is used powder.This binding magnet is poor with the flowability of powder, so, when the magnet moulding, must use high pressure, before, powder filling is inhomogeneous, and when powder added high pressure, core rod tilted easily.But it is inhomogeneous promptly to use this kind powder also can suppress filling among the present invention, prevents the inclination of core rod.
In addition, the invention provides the annular magnet that obtains with above-mentioned ring-like magnet forming apparatus.When the annular magnet that obtains for example is used for Spindle Motor, can make the spin balancing of annular magnet stable, make the action of Spindle Motor stable.
In addition, " front side " of the die cavity described in this specification reaches " rear side ", respectively in the finger print chamber, feed box etc. is to the approach axis front and rear of powder device when die cavity enters.
" axiality " is according to " JIS B0021 subordinate list 11.1 axiality tolerances ", and expression is footpath poor of desirable footpath and the actual fabrication at center with the reference axis with any axial length.Its numerical value is with 2 times of expressions as desirable center and the distance between practical center.
Above-mentioned purpose of the present invention and other purpose, feature, situation and advantage will be more clear in following examples explanation of reference accompanying drawing.
Description of drawings
Fig. 1 is the figure of expression one embodiment of the invention.
Fig. 2 (a) is the sectional drawing of wanting portion of this invention of expression, and Fig. 2 (b) is the figure of its A-A section.
Fig. 3 is the stereogram that dissects metal die along longitudinal direction.
Fig. 4 is the exploded perspective view that dissects metal die along longitudinal direction.
Fig. 5 is the stereogram of an example of expression annular magnet.
Fig. 6 is the curve chart of expression experimental result.
Fig. 7 is the sectional drawing of wanting portion of another embodiment of expression.
Fig. 8 is the sectional drawing of wanting portion of another embodiment of expression.
Fig. 9 is the sectional drawing of wanting portion of another embodiment of expression.
Figure 10 is the sectional drawing of wanting portion of expression embodiment shown in Figure 9.
Figure 11 is the sectional drawing of wanting portion of another embodiment of expression.
Figure 12 is the sectional drawing of wanting portion of another embodiment of expression.
Figure 13 is another routine curve chart of expression experimental result.
Figure 14 is the sectional drawing of an example of the expression Spindle Motor that uses annular magnet.
Embodiment
Below, with reference to accompanying drawing, embodiments of the invention are described.
As shown in Figure 1, the ring-like magnet forming apparatus 10 of one embodiment of the present of invention is shaped devices of former slidingtype, comprises increased pressure frame 12.In increased pressure frame 12, disposing the metal die 14 of former, core rod integral type.
To shown in Figure 4, metal die 14 comprises the former 16 of general cylindrical shape as Fig. 2.Former 16 has through hole 18, blank part 20 and the stage portion 22 of circular cross section.The diameter of blank part 20 is bigger than through hole 18, and is communicated with through hole 18.Stage portion 22 is formed on the bottom of blank part 20.In addition, below former 16,,, use hole 26 towards the accent core of center position roughly uniformly-spaced to form several (being 8 in the present embodiment) in the lateral surface bottom of former 16 uniformly-spaced to form the hole 24 of several (being 4 in the present embodiment) above-below directions.
This former 16 is configured on the former lower panel 28 of circular plate type.On former lower panel 28, the position corresponding with each hole 24 of former 16 forms hole 30 respectively, and inboard slightly in each hole 30 forms roughly fan-shaped hole 32 respectively.32 downside is provided with parts of bearings (slip guiding part) 34 in the hole, and the surface of this parts of bearings 34 flushes with the lateral surface in hole 32.Low punch seat 66 (aftermentioned) is by parts of bearings 34 guidings, the synthesis precision when improving assembling.Former 16 and former lower panel 28 are fixed as one by the screw 36 in patchhole 24 and the hole 30.
On the former lower panel 28 and in the blank part 20 at former 16, disposing core rod 38.Core rod 38 comprises the flange part 40 of circular plate type.On flange part 40, the position corresponding with each hole 32 of former lower panel 28 forms roughly fan-shaped hole 42 respectively.Stage portion 22 with the top and former 16 of former lower panel 28 is held the flange part 40 of core rod 38 under the arm, thereby core rod 38 is fixed.The upper surface of core rod 38 and former 16 top substantially flush.
On the flange part 40 of core rod 38, disposing the low punch packing ring 48 of annular, the low punch 50 of general cylindrical shape and the low punch foundary weight 52 of annular successively.On low punch packing ring 48, alternately form the fixing fixing hole 56 of using of several (being each 4 in the present embodiment) low punch seats 66 with hole 54 and low punch foundary weight 52.In the lateral surface bottom of low punch 50, form stage portion 58, on low punch foundary weight 52, the position corresponding with each hole 56 of low punch packing ring 48 forms hole 60 respectively, at the interior basifacial of low punch foundary weight 52, forms stage portion 62.
Below low punch packing ring 48, low punch seat 66 is installed.Low punch seat 66 has 4 axial regions 68 that roughly are fan-shaped section, and these 4 axial regions 68 run through the hole 32 of former lower panel 28 and the hole 42 of core rod 38.On each axial region 68, the position corresponding with each hole 54 of low punch packing ring 48 forms through hole 70.The axial region 68 of low punch seat 66 is passed hole 32 and hole 42, screw 72 is penetrated hole 70 and hole 54, like this, low punch seat 66 and low punch packing ring 48 become one.
Again as shown in Figure 1, the low punch seat 66 of the metal die 14 of Xing Chenging like this, be configured on the low punch seat cushion circle 74, the bottom that is keeping low punch seat 66 by low punch seat foundary weight 76, screw 78 is inserted low punch seat foundary weight 76 and low punch packing ring 74, like this, low punch seat 66 just is fixed on the low punch seat cushion circle 74.Low punch seat cushion circle 74 is configured on the substrate 82 and with screw 84 and fixes, and this substrate 82 is being supported by the foots 80 in the increased pressure frame 12.Like this, low punch 50 is fixed.
On substrate 82, form through hole 86, in through hole 86, be provided with guiding axle bush 88.
Former 16 is being kept by former guard ring 90 and former foundary weight 92, and screw 94 is inserted in former foundary weight 92 and the former guard ring 90, and former 16 just is fixed.Below former guard ring 90, be connected base station 98 with the bottom by post 96 and connect, the bottom connects base station 98 and is connected with pressurization bottom pressure head 100.By making pressurization bottom pressure head 100 moving up and down, can make former 16 and core rod 38 moving up and down, former is slidably.
In addition, on former guard ring 90, stand and establishing upper punch guide posts 102, upper punch plate 104 is guided at above-below direction by upper punch guide posts 102.Below upper punch plate 104, upper punch 110 is being kept by upper punch packing ring 106 and upper punch foundary weight 108, and screw 112 is inserted upper punch packing ring 106 and upper punch foundary weight 108, and upper punch 110 just is fixed.On upper punch plate 104, connecting pressurization top pressure head 114, by making pressurization top pressure head 114 moving up and down, can make upper punch 110 moving up and down, upper punch 110 can be advanced and retreat in die cavity 65.
In addition, near increased pressure frame 12, disposing can be with respect to the feed box 116 of die cavity 65 advance and retreat.In feed box 116, accommodating the powder 118 of feeding chamber 65.Powder 118 for example is the binding magnet powder that is coating resin adhesive on rare earth alloy powder.This powder is for example made like this: by using in the powder at the MQP-B magnet of MQI society system, sneak into weight ratio and be 1%～5% epoxy resin etc. and make it dry, just can make the binding magnet that coating resin with powder (for example the spy opens the 2000-119702 communique).The particle diameter of mixture is 30 μ m～250 μ m.Above-mentioned powder, thickness are 20 μ m～50 μ m, ratio (aspect ratio) less than 0.3 of minor axis and major axis.
Below, the accent core action of the core rod 38 in the ring-like magnet forming apparatus 10 is described.
In former 16, accommodating under the state of low punch 50, core rod 38 etc., screw 36 is tightened to and can the degree of core rod 38 accent cores be fixed on former 16 on the former lower panel 28.At this moment, core rod 38 is configured on the former lower panel 28.
Along full week, the hole 26 interior accent cores that will be screwed into former 16 are singly successively tightened gently with screw 44, measure the clearance G of regulating usefulness with pin gauge (figure does not show).The result who measures clearance G along full week is, if clearance G (maximum-minimum value) surpasses 5 μ m, then the accent core of the little part of clearance G is unscrewed with screw 44, perhaps the accent core of the big part of clearance G is more tightened with helical 44, clearance G (maximum-minimum value) is adjusted to below the 5 μ m.Like this, after core rod 38 was transferred core, tighten the screws 36 again, and was integrated former 16, former lower panel 28 and core rod 38.
Among this embodiment, when the external diameter X of former 16 was the 120mm left and right sides, the length L of core rod 38 was set at about 75mm.In addition, former 16 and the gap of low punch 50 and the gap of core rod 38 and low punch 50 are set in 5 μ m～10 μ m.
Exist the action of this ring-like magnet forming apparatus 10 of simple declaration down.
At first, in the die cavity 65 that forms in that former 16 and core rod 38 are risen, fill the powder 118 in the feed box 116.Then, upper punch 110 is descended, with powder 118 extrusion modlings in the die cavity 65 towards die cavity 65.At this moment, the powder 118 in the die cavity 65 are by upper punch 110 and low punch 50 compressions, to the extruding force of powder 118 usually more than the 500MPa, below the 1500MPa.If a pair of not enough 500MPa of extruding force that goes up low punch 110,50 then in annular magnet 120 (see figure 5)s that obtain, can not get required magnetic.On the other hand, if extruding force has surpassed 1500MPa, the power that then is added on former 16 and the core rod 38 is excessive, causes metal die 14 breakages sometimes.As mentioned above, as long as a pair of extruding force that goes up low punch 110,50 is controlled at more than the 500MPa, below the 1500MPa, just can avoids the problems referred to above.The more preferably scope of extruding force is more than the 700MPa, below the 1300MPa.Be set at 1200MPa among this embodiment.
After upper punch 110 is risen, former 16 and core rod 38 are descended, the annular magnet 120 that obtains is exposed on the former 16, again with its taking-up.
According to this ring-like magnet forming apparatus 10, because former 16 and core rod 38 are fixed on the former lower panel 28 integratedly, so can securely core rod 38 be fixed, make core rod 38 not eccentric with respect to former 16, can stably obtain the position relation of former 16 and core rod.Even inhomogeneous during filling powder 118 in the die cavity 65, when moulding since core rod 38 do not tilt, so powder 118 flows, and can obtain the little high-quality circular ring magnet 120 of axiality.Can improve the rate of finished products and the productivity of annular magnet 120.
In addition,,, do not need very masterful technique, can make assembly precision more stable so the assembling of metal die 14 is easy owing to can shorten core rod 38 (being 75mm in the present embodiment).
By core rod 38 being transferred core on one side with screw 44 with the accent core, on former lower panel 28, assemble former 16 and core rod 38, the die cavity 65 of available needs, result on one side, can further suppress the axiality of annular magnet 120, may be molded to required annular magnet 120.
In addition, if the extruding force of upper punch 110 and low punch 50 more than the 500Mpa, below the 1500MPa, then can obtain the annular magnet 120 of required magnetic, and can prevent metal die 14 breakages.
The present invention sneaks into resin adhesive in the rare earth alloy powder and particularly effective during the binding magnet powder that forms in compacting.This is because the flowability of this binding magnet powder is poor, thus when moulding magnet, must use high-pressure extrusion, when before powder being added high pressure, core rod tilts easily, and by ring-like magnet forming apparatus 10 of the present invention, can securely core rod 38 be fixed, can prevent the inclination of core rod 38.
In addition, the present invention is that 2.5mm is particularly effective when following at the thickness of annular magnet 120.At this moment because if the thickness of the annular magnet of making 120 is little,, also cause off-centre increasing, the axiality of annular magnet 120 to worsen even core rod 38 a little tilts.
With the annular magnet of ring-like magnet forming apparatus 10, as shown in Figure 6 with conventional example (metal die that adopts former to separate) moulding with core rod.In this test, 100 annular magnets that obtain are asked its axiality.In addition, the size of annular magnet is set at external diameter 31mm, internal diameter 28.4mm, height 3.9mm, thickness 1.3mm (external diameter-internal diameter) ÷ 2.
As can be seen from Figure 6, in the prior embodiment, axiality nearly all surpasses 20 μ m, and ring-like magnet forming apparatus 10 then can be suppressed at axiality below about 15 μ m, can improve axiality significantly.
In another test,, in example before, be 24.8mgcm, and in the ring-like magnet forming apparatus 10, then can be improved to 9.9mgcm about amount of unbalance.Here said " amount of unbalance " is to represent with unshapeliness weight and the amassing of radius that has this unshapeliness weight.
Therefore, the little high-quality annular magnet 120 of axiality can be obtained, rate of finished products and productivity can be improved.
Below, with reference to Fig. 7 another embodiment is described.Among this embodiment, metal die 14 comprises the low punch 122 that replaces low punch 50.The front end face of low punch 122 as shown in Figure 7, forms inclined plane 122a, and this inclined plane 122a is towards the direction of retreat of the feed box 116 shown in the arrow e, promptly scrape and smear direction toward tilting.Except low punch 122 had inclined plane 122a this point, all the other were identical with the 1st embodiment.The difference of height L of the inclined plane 122a of low punch 122 for example is set at 30 μ m.At this moment, the maximum difference of the degree of depth of the front side 65b of die cavity 65 and rear side 65a also is 30 μ m.
The top of low punch 122 in the through hole 18 of former 16, in the through hole 18 of former 16, is formed the die cavity 65 of annular by the inclined plane 122a of former 16, core rod 38 and low punch 122.In addition, die cavity 65 is smeared direction towards scraping of feed box 116 and is shoaled by the inclined plane 122a of low punch 122.The depth ratio front side 65b of rear side 65a is shallow in die cavity 65.
Below, the action of the ring-like magnet forming apparatus 10 that adopts this low punch 122 is described.
Former 16 and core rod 38 are risen, form die cavity 65.Then, make feed box 116 towards with Fig. 7 in scrape the side of smearing in the opposite direction shown in the arrow e, enter former 16.At this moment, the powder 118 in the feed box 116 is in action of gravity drops to die cavity 65.After the sand off, feed box 116 is decorporated towards the direction opposite with approach axis (scraping shown in the arrow e smeared direction), wipes unnecessary powder off with the bottom margin of feed box 116.At this moment, in die cavity 65, the depth as shallow of the depth ratio front side 65b of rear side 65a is supplied with powder under this state.
Then, upper punch 110 is descended, with powder 118 compression mouldings in the die cavity 65 towards die cavity 65.At this moment, the powder 118 in the die cavity 65 is by upper punch 110 and low punch 122 compressions, and is same with the 1st embodiment to the extruding force of powder 118, normally more than the 500MPa, below the 1500MPa.The more preferably scope of extruding force is more than the 700MPa, below the 1300MPa, is set at 1200MPa in the present embodiment.
After upper punch 110 is risen, former 16 and core rod 38 are descended, the annular magnet that obtains is exposed to former 16, it is taken off.By the annular magnet that takes out is carried out chamfer machining, obtain annular magnet 120.
According to this embodiment, except can obtain with the same effect of the 1st embodiment, also have following effect.
According to this embodiment, because the inclined plane 122a of low punch 122 smears direction toward tilting towards scraping shown in the arrow e, so in die cavity 65, the depth as shallow of the depth ratio front side 65b of rear side 65a.Therefore usually the closer to the rear side 65a of die cavity 65, powder 118 is more by powerful filling, and packing density is high more, still, can make the charging quantity of powder 118 toward the front side 65b of die cavity 65, and is more than the charging quantity toward rear side 65a.Therefore, in die cavity 65, the briquetting pressure that can lower between the position is poor, can make the compact density of the annular magnet that obtains by the powder 118 in the compacting die cavity 65 roughly even, the result, the annular magnet 120 of the little annular of axiality can be obtained, the rate of finished products and the productivity of annular magnet 120 can be improved.
In addition, coat rare earth alloy powder and during the binding magnet powder that forms, it is inhomogeneous also to suppress filling, can prevent the inclination of core rod 38 even adopt by resin adhesive.
Below, with reference to Fig. 8 another embodiment is described.Among this embodiment, metal die 14 comprises the low punch 50 with horizontal front end face 50a and has upper punch 124 with front end face 50a inclined plane 124a in opposite directions, to replace low punch 122 and upper punch 110.Inclined plane 124a tilts, so as to make and front end face 50a between the interval smear direction towards scraping of feed box 116 shown in the arrow e and increase.The difference of height M of inclined plane 124a for example is set at 60 μ m.At this moment, the front end face of upper punch 124 is that the largest interval difference of the front end face 50a of inclined plane 124a and low punch 50 also is 60 μ m.
Like this, tilt by the front end face that makes upper punch 124, the interval between the front end face of the last low punch 124,50 when making moulding, bigger at the rear side 65a of die cavity 65 than front side 65b, the volume increase when making the compacting of the many parts of charging quantity.
According to this embodiment, even pattern chamber 65 rear side 65a packing densities are high more more, front end face 50a when moulding and interval even the volume between the 124a of inclined plane, the rear side 65a that is pattern chamber 65 more is big more, so, in die cavity 65, the briquetting pressure that can reduce between the position is poor, makes the compact density of the annular magnet that obtains roughly even.Therefore, the little high-quality annular magnet 120 of axiality can be obtained, the rate of finished products and the productivity of annular magnet 120 can be improved.
In addition, among this embodiment, in the time of changing the height dimension of annular magnet 120 of making, as long as replace with drift 124.
Below, with reference to Fig. 9 and Figure 10, another embodiment is described.Among this embodiment, replace former 16, replace core rod 38 with core rod 127 with former 126.Among on former 126,, form inclined plane 126a at the periphery of die cavity 65.Inclined plane 126a smears direction toward having a down dip towards scraping of feed box 116 shown in the arrow e.Like this, with respect to the approach axis of feed box 116, the rear side 65a of die cavity 65 is more shallow than front side 65b, and its difference of height N for example is set at 30 μ m.At this moment, the depth capacity difference of the front side 65b of die cavity 65 and rear side 65a also is 30 μ m.In addition, become inclined plane 127a above the core rod 127, this inclined plane 127a be included in the inclined plane 126a of former 126 with in the one side.The front end face 50a of low punch 50 and the front end face 110a of upper punch 110 are levels, do not tilt.
Among this embodiment, during powder feeding, powder feeding under the state of the depth as shallow of the depth ratio front side 65b of the rear side 65a of die cavity 65.
According to this embodiment, even the closer to the rear side 65a of die cavity 65, packing density is high more, but because die cavity 65 is that to arrive rear side 65a more shallow more, so the charging quantity of powder 118 each position in die cavity 65 is roughly the same.Therefore, the briquetting pressure that can reduce film chamber 65 inner interdigits is poor, makes compact density roughly even.The little high-quality annular magnet 120 of axiality can be obtained thus, the rate of finished products and the productivity of annular magnet 120 can be improved.
Below, with reference to Figure 11, another embodiment is described.Among this embodiment, metal die 14 comprises low punch 128 that replaces low punch 50 and the upper punch 110 with horizontal front end face 110a.On the front end face of low punch 128, form inclined plane 128a and horizontal plane 128b, inclined plane 128a smears direction toward tilting towards scraping of feed box 116 shown in the arrow e.Horizontal plane 128b smears the direction side than scraping of the close feed box 116 of inclined plane 128a.The area of inclined plane 128a and horizontal plane 128b about equally.The difference of height S of inclined plane 128a for example is set at 30 μ m.At this moment, the depth capacity difference of the front side 65b of die cavity 65 and rear side 65a also is 30 μ m.
According to this embodiment, though the packing density height of the powder 118 of the rear side 65a of die cavity 65, because die cavity 65 is that front side 65b is dark, so, can make to powder 118 charging quantities of the front side 65b of die cavity 65 bigger than the charging quantity of 65a rearward.Therefore,, the little circular annular magnet 120 of axiality can be obtained, the rate of finished products and the productivity of annular magnet 120 can be improved with similarly embodiment illustrated in fig. 7.
Below, with reference to Figure 12, another embodiment is described.Among this embodiment, metal die 14 comprises upper punch 130 that replaces upper punch 110 and the low punch 50 with horizontal front end face 50a.At the front end face of upper punch 130, form inclined plane 130a and horizontal plane 130b.Inclined plane 130a is arranged on than scraping of feed box 116 shown in the more close arrow e of horizontal plane 130b and smears the direction side.Inclined plane 130a tilts, so as to make and front end face 50a between the interval smear direction towards scraping of feed box 116 and increase.The difference of height T of inclined plane 130a for example is set at 30 μ m.At this moment, the maximum difference at interval also is 30 μ m between the front end face 50a of the front end face of upper punch 130 and low punch 50.The area of inclined plane 130a and horizontal plane 130b about equally.
According to this embodiment, even rear side 65a the closer to die cavity 65, the packing density of powder 118 is high more, but owing to be that to arrive the rear side 65a of die cavity 65 more big more at interval between the front end face 50a of the front end face of the upper punch 130 during moulding and low punch 50, so, with Figure 10 and similarly embodiment illustrated in fig. 11, compact density is roughly even.Therefore, the circular annular magnet 120 of the little high-quality of axiality can be obtained, the rate of finished products and the productivity of annular magnet 120 can be improved.
In addition, difference of height L, M, N, S and T are when the annular magnet that the making Spindle Motor is used, preferably more than the 0.01mm, below the 0.15mm.If in this scope, can offset powder 118 inhomogeneous during filling in the die cavitys 65, can make the compact density of annular magnet roughly even.If surpass this scope, it is inhomogeneous then to produce filling.In addition, the scope of difference of height L, M, N, S and T is 30 μ m～90 μ m.The scope of difference of height L, M, N, S and T can suitably change according to the size of the annular magnet 120 that will make.
The ratio of the area of the area of the area ratio of the area of inclined plane 128a and horizontal plane 128b and inclined plane 130a and horizontal plane 130b is 1: 1 in the above-described embodiments, but is not limited thereto.
When Figure 13 represents to adopt the metal die 14 that the upper punch 124 that will have inclined plane 124a and former 16 and core rod 38 be fixed as one (below be called " inclination upper punch one metal die "), when adopting the existing metal die that the low punch 122 that will have inclined plane 122a separates with former and core rod (below be called " the inclination low punch have metal die ") and the existing drift that will not tilt when being used for having now metal die (below be called " existing metal die does not tilt "), the result of the annular magnet of moulding.In this test, 1000 annular magnets that obtain are asked its axiality.In addition, the size of annular magnet is external diameter 31mm, internal diameter 28.4mm, height 3.9mm, thickness 1.3mm=(external diameter-internal diameter) ÷ 2.
As can be seen from Figure 13, adopt not tilt existing metal die the time, axiality nearly all surpasses 20 μ m, when adopting the inclination low punch to have metal die now, axiality can be suppressed at below the 20 μ m, and adopts when having the low punch 122 of inclined plane 122a, can improve axiality.Therefore, the present invention also is effective for the existing metal die that adopts former and core rod separate type.
In addition, when adopting inclination upper punch integral type metal die, axiality can be suppressed at below the 8 μ m.In the metal die 14 that former 16 and core rod 38 one are fixed, adopt when having the upper punch 124 of inclined plane 124a, can improve axiality significantly.
In addition, the inclined plane is as long as form at least one of former and core rod, upper punch, low punch.
By the annular magnet 120 that the present invention obtains, for example can be used for Spindle Motor 200 as shown in Figure 14.
If the annular magnet 120 that has improved axiality is used for Spindle Motor 200, even when making Spindle Motor 200 high speed rotating, the spin balancing of annular magnet 120 is also stable.Therefore, even Spindle Motor 200 is used for the hard disk drive that rotary speed is 10000rpm, also can obtain stable action.
Describe in detail by embodiment above and illustrate the present invention, but the present invention is not limited to these embodiment and diagram, the spirit and scope of the present invention only are defined by the claims.
Claims (9)
1. a ring-like magnet forming apparatus wherein, possesses the former of coherent through hole; The core rod that in described through hole, is fixed as one for formation annular die cavity and described former; And the powder of a pair of squeeze pack in described die cavity is to obtain the drift of annular magnet.
2. ring-like magnet forming apparatus as claimed in claim 1 is characterized in that, comprises to regulate described core rod so that obtain the centering machine structure of required die cavity.
3. ring-like magnet forming apparatus as claimed in claim 1 or 2 is characterized in that described die cavity forms annular.
4. ring-like magnet forming apparatus as claimed in claim 1 or 2, it is characterized in that, described a pair of drift is upper punch and low punch, also have along described female mold surfaces move, with powder scrape smear to powder in the described die cavity to the powder device, on the surface of described former and described core rod and at least a portion of at least any one party in the low punch front end face, have towards described scraping and smear the inclined plane that direction tilts, make the depth as shallow of in the described die cavity depth ratio front side of rear side.
5. ring-like magnet forming apparatus as claimed in claim 1 or 2, it is characterized in that, described a pair of drift is upper punch and low punch, also have along described female mold surfaces move, with powder scrape smear to powder in the described die cavity to the powder device, at least a portion at the front end face of described upper punch, have towards described scraping and smear the inclined plane that direction tilts, make the interval between described upper punch and described low punch front end face bigger than front side at the rear side of described die cavity.
6. ring-like magnet forming apparatus as claimed in claim 4 is characterized in that, the difference of height on described inclined plane is more than the 0.01mm, below the 0.15mm.
7. ring-like magnet forming apparatus as claimed in claim 5 is characterized in that, the difference of height on described inclined plane is more than the 0.01mm, below the 0.15mm.
8. a metal die that is used for the moulding annular magnet wherein, possesses the former of coherent through hole, and the core rod that is fixed as one for formation annular die cavity and described former in described through hole.
9. annular magnet that obtains with claim 1 or 2 described ring-like magnet forming apparatus.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001009226A JP3223251B1 (en) | 2001-01-17 | 2001-01-17 | Ring-shaped magnet forming apparatus and mold used for it |
| JP20019226 | 2001-01-17 | ||
| JP2001280436 | 2001-09-14 | ||
| JP2001280436A JP3310972B1 (en) | 2001-09-14 | 2001-09-14 | Ring-shaped magnet forming apparatus and ring-shaped magnet forming method |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005100643581A Division CN100354994C (en) | 2001-01-17 | 2002-01-17 | Ring-like magnet forming apparatus and metallic mold used therefor, and ring-like magnet forming method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1366317A CN1366317A (en) | 2002-08-28 |
| CN1228799C true CN1228799C (en) | 2005-11-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005100643581A Expired - Lifetime CN100354994C (en) | 2001-01-17 | 2002-01-17 | Ring-like magnet forming apparatus and metallic mold used therefor, and ring-like magnet forming method |
| CN 02101737 Expired - Lifetime CN1228799C (en) | 2001-01-17 | 2002-01-17 | Ring shaped magnetic shaping device and its used metal mould and ring shaped magnet shaping method |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005100643581A Expired - Lifetime CN100354994C (en) | 2001-01-17 | 2002-01-17 | Ring-like magnet forming apparatus and metallic mold used therefor, and ring-like magnet forming method |
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| Country | Link |
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| CN (2) | CN100354994C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101412292B (en) * | 2007-10-19 | 2011-09-14 | 德伟国际股份有限公司 | Powder compacting shape machine with embedded metal coil and method for moulding inductor by using the same |
| CN102800839B (en) * | 2011-05-23 | 2014-12-10 | 无锡博士能环保电池有限公司 | Device and method for preparing electrode of battery |
| CN109604590A (en) * | 2019-01-28 | 2019-04-12 | 成都图南电子有限公司 | It is a kind of for bonding the single mode multi-cavity molding die of ferro-aluminum boron |
| CN113470958B (en) * | 2021-06-30 | 2023-03-24 | 安徽恒磁磁电有限公司 | Forming device is used in production of ultra-thin bonding neodymium iron boron magnetism body |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05156305A (en) * | 1991-12-06 | 1993-06-22 | Nissan Motor Co Ltd | Device for compacting sintered part |
| JP3347451B2 (en) * | 1993-10-27 | 2002-11-20 | 株式会社ユニシアジェックス | Molding apparatus for green compaction and molding method |
| JPH1180805A (en) * | 1997-09-01 | 1999-03-26 | Toyota Motor Corp | Production of sintered member |
| JP3693496B2 (en) * | 1998-05-25 | 2005-09-07 | 日立粉末冶金株式会社 | Molding method of green compact |
| JP2001009596A (en) * | 1999-06-29 | 2001-01-16 | Hitachi Metals Ltd | Powder compression molding method |
-
2002
- 2002-01-17 CN CNB2005100643581A patent/CN100354994C/en not_active Expired - Lifetime
- 2002-01-17 CN CN 02101737 patent/CN1228799C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CN1667765A (en) | 2005-09-14 |
| CN1366317A (en) | 2002-08-28 |
| CN100354994C (en) | 2007-12-12 |
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