GB2217651A - Magnetic plastic rotor disk - Google Patents
Magnetic plastic rotor disk Download PDFInfo
- Publication number
- GB2217651A GB2217651A GB8909713A GB8909713A GB2217651A GB 2217651 A GB2217651 A GB 2217651A GB 8909713 A GB8909713 A GB 8909713A GB 8909713 A GB8909713 A GB 8909713A GB 2217651 A GB2217651 A GB 2217651A
- Authority
- GB
- United Kingdom
- Prior art keywords
- magnetic
- magnetic plastic
- rotor disk
- cavities
- injection device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000004033 plastic Substances 0.000 title claims description 59
- 239000000463 material Substances 0.000 claims description 37
- 238000002347 injection Methods 0.000 claims description 27
- 239000007924 injection Substances 0.000 claims description 27
- 238000004519 manufacturing process Methods 0.000 claims description 21
- 238000000465 moulding Methods 0.000 claims description 14
- 239000006247 magnetic powder Substances 0.000 claims description 12
- 239000011159 matrix material Substances 0.000 claims description 4
- 229920003002 synthetic resin Polymers 0.000 claims description 3
- 239000000057 synthetic resin Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 description 12
- 230000004907 flux Effects 0.000 description 4
- 230000005389 magnetism Effects 0.000 description 4
- 238000005520 cutting process Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- ZPEZUAAEBBHXBT-WCCKRBBISA-N (2s)-2-amino-3-methylbutanoic acid;2-amino-3-methylbutanoic acid Chemical compound CC(C)C(N)C(O)=O.CC(C)[C@H](N)C(O)=O ZPEZUAAEBBHXBT-WCCKRBBISA-N 0.000 description 1
- AYFVYJQAPQTCCC-GBXIJSLDSA-N L-threonine Chemical compound C[C@@H](O)[C@H](N)C(O)=O AYFVYJQAPQTCCC-GBXIJSLDSA-N 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- KVFIJIWMDBAGDP-UHFFFAOYSA-N ethylpyrazine Chemical compound CCC1=CN=CC=N1 KVFIJIWMDBAGDP-UHFFFAOYSA-N 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000010137 moulding (plastic) Methods 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/26—Moulds
- B29C45/27—Sprue channels ; Runner channels or runner nozzles
- B29C45/2701—Details not specific to hot or cold runner channels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/0013—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor using fillers dispersed in the moulding material, e.g. metal particles
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
Description
MAGNETIC PLASTIC ROTOR DISK MANUFACTURING APPARATUS The present invention
relates to an apparatus for manufacturing magnetic plastic rotor disks. and more particularly to such an apparatus suitable for production of flattened columnar magnetic plastic rotor disks to be used as meter rotors. for example.
Such a magnetic plastic rotor disk is conventionally used for a vehicle meter such as a vehicle speed meter and an engine speed meter for indicating rotating speeds corresponding to a vehicle speed and rotational frequency of the engine thereof. Fig.4 shows a magnetic plastic rotor disk b having a central rotary shaft a and magnetized in one direction perpendicular to the rotary shaft a to have an N-pole and an S-pole at diametrically opposite positions. The magnetic plastic rotor disk b is required to have a charact-eristic as shown in Fig.5 wherein distribution of a magnetic flux density on outer circumferential surface of the magnetic plasti rotor disk b varies sinusoidally with respect rotary angle of the magnetic Fig.6 shows a convention manufacturing such a magneti Referring to Fig.6, a magnet t o a plastic rotor disk b. al apparatus for c plastic rotor disk. ic plastic material A and a magnetic powder is injected from an injection device B through a sprue and runner D formed in a two-plate side gate type mold C 1 ' -, i nt o a d c s i g plurality of cavities E. A reference numeral F ates a yoke around which a coil (not shown) is wound. The yoke F is so located as to surround a parting surfact C' of the mold C. so that a magnetic field is applied to the magnetic plastic material A injected into the cavities in one direction as shown in Fig.7 to thereby magnetize the magnetic powder contained in the material A so that the particles of the magnetic powder are magnetized in the same magnetic orientation.
However, since this conventional magnetic plastic rotor disk manufacturing apparatus is of a side gate type having two plates. a gate blush remarkably appears on the externa disk after moldi distribution of magnetic plastic surfaces of the magnetic plastic rotor ng, causing turbulence of the the surface magnetic flux density of the rotor disk. characteristic of the magnetic be obtained. Accordingly, it 1 deflashing process after a gat As a result. a desired plastic rotor disk cannot 5 necessary to conduct a e cutting process. Further. if the magnetic plastic rotor disk is in a magnetized condition in the deflashing process, small flash particles generated in the deflashing process will be magnetically attached to the rotor disk. Therefore, it is necessary to demagnetize the rotor disk before the deflashing process and then magnetize the same again after the deflashing process. Thus, many troublesome processes are necessary after molding in the prior art device, causing an increase in production cost.
It is an object of the present invention to provide a magnetic plastic rotor disk manufacturing apparatus which may eliminate the necessity of the aforementioned troublesome processes after molding of the magnetic plastic material.
According to the present invention, there is provided an apparatus for manufacturing magnetic plastic rotor disks, comprising an injection device for injecting a magnetic plastic material containing a synthetic resin matrix and a magnetic powder; a mold for molding the magnetic plastic material injected thereinto from the injection device, the mold comprising a threeplate type mold constructed of two retainer plates and a single runner stripper plate, one of the retainer plates g formed with a plurality of cavities, while the other retainer plate being formed with a plurality of pin gates corresponding to the cavities so as to supply the magnetic plastic material through the pin gates into the cavities; and means for generating a magnetic field and magnetizing the magnetic powder in a direction along a diameter of the magnetic plastic rotor disk.
b e 1 n In the above-mentioned manufacturing apparatus, one (if opposite end surfaces of each magnetic rotor disk having a columnar shape is molded by each cavity formed tin one of the two retainer plates, and the pin gates are formed in the other retainer plate in such a manner as to be connected with the cavities. With this rangement. when the mold is opened to split the two retainer plates form each other, the pin gates are automaticully cut with greatly small gate blush remaining. Acc(irdingly, it is unnecessary to conduct the gate cutting process and the gate blush removing process after molding of the magnetic plastic material. Since the gate blush removing process is unnecessary, it necessary to remove the magnetism of the moldings e, magnetic rotor disks may also be greatly i s no and magnetize the moldings again. Therefo characteristic of the magnetic plastic be improved, and a reduced.
Furthermore, th constructed of a production cost may e injection device is preferably screw injection device having a screw head provided with a check valve for preventing backflow of the magnetic plastic material. Accordingly, although an injection force is enlarged by the use of pin gates, the backflow of the material upon injection may prevented. As a result, a cushion quantity may ensured to greatly improve shot scattering of the be be 1 1 material into the cavities, thereby improving the quality and magnetic characteristic of the moldings.
Other objects and features of the invention will be more fully understood from the following detailed description and appended claims when taken with the accompanying drawings.
Fig.1 is a partially sectional side view of a preferred embodiment of the manufacturing apparatus according to the present invention; Fig.2A. 2B and 3 are sectional views of some preferred embodiments of the injection device according to the present invention; Fig.4 is a perspective view of the magnetic plastic rotor disk to be produced by the magnetic plastic rotor disk manufacturing apparatus of the present invention; Fig.5 is a waveform chart illustrating an ideal waveform of distribution characteristic of a magnetic flux density on a surface of the magnetic plastic rotor disk shown in Fig-4; Fig.6 is a sectional view of the conventional manufacturing apparatus; and Fig.7 is a plan view of a part of the manufacturing apparatus shown in Fig.6.
There will be described a preferred embodiment of the present invention with reference to the drawings.
Referring to Fig-I which is a partially sectional side view of the magnetic plastic rotor disk manufacturing apparatus, designates a threeplate injection mold. The thre two retainer plates 11 and surface la is formed, and a 13 forming a and the retainer plate is opened to separate runner removing surfac Mounting plates Ila an retainer plate 11 and molding mac The ret surface, i. of cavities III forming a surfaces eference numeral I generally ype mold for use as an -plate mold I is composed (if between which a parting single runner stripper plate g surface lb between the same 12, wherein every time the mold 1 oth the plates 12 and 13, the lb is opened to remove a runner. 13a are provided to mount the the runn shown), respectively. e 11 is formed on its upper h! ne (not a i ner pia the parting surface la with a plurality each having a predetermined depth for n outer circumferential surface and one of end of the magnetic plastic rotor disk having a flattened columnar shape. The mounting plate 13a and the runner stripper plate 13 are formed at their central portions with a sprue 14 for guiding a magnetic plastic er stripper plate 13 to a 1 Q material therethrough. A runner 15 is formed on an upper surface of the runner stripper plate 13,-that is, on a butting surfce between the runner stripper plate 13 and the retainer plate 12. for feeding the magnetic plastic material from the sprue 14 along the butting surface. Further, a plurality of pairs of pin gates 16 are formed in the retainer plate 12 for injecting the magnetic plastic material from the runner 15 t( the cavities 111. That is, formed as to correspond opposite side of the end surfaces of th plastic rotor disk to be produced.
Each pair of pin gates 16 ar radially spaced positions such spaced by 0. 5r - 0.8r (r:
r disk) from the cente rotor disk. Thus, the pin ga their small outlet Therefore, when the mold easily stripped off from appearance of gate blush.
Reference numeral 2 designates an injection device for injecting the magnetic plastic material into the mold I. Some preferred embodiments of the injection device 2 will be hereinafter described.
each pair of pin gates 16 are to each cavity 111 and form the e magnetic r a d r o preferably located at that each pin gate 16 is us of the magnetic plastic the magnetic plastic es 16 are connected at he cavities Ill. opened, the runner can be oldings with 1 e s s 1 Reference numeral 3 designates a yoke around which a coil (not shown) is wound. The yoke 3 is so arranged as to surround-the mold I along the parting surface la of the mold I._so that a magnetic field to be generated by the yoke 3 may be applied to the material in the cavities III in one direction to thereby magnetize a magnetic powder contained in the material so that the particles of the magnetic powder are magnetized in the same magnetic orientation.
The magnetic plastic material contains synthetic resin as a matrix and the magnetic powder such as ferrite or rare earth elements. When the magnetic plastic material is i he -lo-ed -old I njected from the injection device 2 into t, it is supplied through the sprue 14. the runner 15 and the pin gates 16 into the cavities 113. The magnetic powder in the magnetic plastic material is magnetized by the magnetic flux generated across the cavities 111 by the yoke 3, and is oriented in the same direction as a direction of the magnetic f 1 11X - the cavities 111, the mold I is ope e n by a driving (not shown) to cut off the sprue and runner at of the pin gates 16. Then. the sprue and eparated together with the retainer plate 12 from the retainer plate 11. As a result, the magnetic plastic moldings are formed in the cavities 111, and they are ejected from the cavities Ill by ejector pins by moving an ejector plate (riot shown).
The magnetic plastic rotor disk thus produced has magnetism in its diametrical direction. A gate blush remaining (in one end surface (if the magnetic plastic ri)tor disk' is extremely small. Accordingly, it is to conduct a gate cutting process and a gate ng process after molding the magnetic ial. AS a result, it is unnecessar magnet i sin f rom the moldin unnecessary blush removi p I a s t i c m a t e r y t o rem(ive the gs in conducting the gate blush removing process and apply the magnetism to the moldings again after the gate blush removing process. In this manner, the moldings of the magnetic plastic material after being ejected from the cavities 111 can be utilized for products without any post- treatment.
In opening the mold 1, the ret runner stripper plate 13 are split the runner removing surface Ib formed therebetween, so that the sprue and. runner may be removed from the retainer plate 12.
The orientation of the magnetism is not the above-mentioned preferred embodiment, it may be suitably modified in accordance with the arrangement of ainer plate 12 and the from each other at - 10 the cavities. for example.
Figs-2A, 2B and 3 show some preferred embodiments of the injection device 2 to be used with the magnetic plastic rot-or disk m.anufacturing apparatus according to the present invention.
Referring first to Figs.2A and 2B, the injection device 2 is provided with a screw 22 adapted to be rotated and reciprocated in a cylinder 21. a screw head 23 fixed at its base to the screw 22 with a valve seat 25 interposed therebetween, and a backflow ring check valve 24 operatively mounted around the screw head 23. The check valve 2-4 serves to prevent backflow of a part of the magnetic plastic material through a screw channel of the screw 22 caused by a reaction of an injection force to be applied to the material upon injection of the material from a nozzle of the injection device 2.
In metering the material as shown in Figs-2A, the screw 22 is rotated to be retracted, and the material is accordingly fed through a gap defined between the valve seat 25 and the check valve 24. In injecting the material as shown in Fig-2B, the check valve 24 is urged back by the reaction of the injection force applied to the material until the valve 24 abuts against the valve seat 25. Thus the gap between the check valve 24 and the valve seat 25 is closed to thereby prevent the backflow of the material.
1 referring next to Fig.3 which shows another type clieck valve. a ball cheek valve 26 is provided in the screw head 23 in such a manner that the ball cheek valve 26 is operatively moved in a hole 23a formed in the screw head 23.
In the above-mentioned preferred embodiment employing the pin gates 16 and accordingly necessitating the application of a large injection force to the material having a high viscosity and a low fluidity. the to flow back because (if the reaction of orce upon injection of the material. the injection device 2 is provided with 24 or 26 for large inject improve shot material tends the injection However, sinc the check valv t h e m a t e r i a 1, thereby greati quality and well as the By usin apparatus, the diameter o from a magnetic plastic material containing 12-nylon as the matrix and 89 wt.% of strontium ferrite as the magnetic powder under the injection condition of 53 g per shot. The magnetic plastic rotor disk thus produced was compared with that produced by the conventional manufacturing apparatus employing a straight head screw, preventing the backflow of ion force may be ensured to scattering. Therefore, the magnetic characteristic of the moldings as productivity may be improved. the above-mentioned manufacturing magnetic plastic rotor disk having a 12 mm and a thickness of 3 mm was produced - 12 and various propert ies were evaluated as shown in Table be 1 ow.
Tab I c Waveform Zero-cross position Cushion quantity (g) bletered quantity (g) Shot scattering Molding quality Present invention Prior Art
0 63 0 0 77 A 0 Re-magnetization unnecessary necessary Productivity X Production cost A Although there has not been referred to a rotary shaft of the magnetic plastic rotor disk in the abovementioned preferred embodiment, the rotary shaft may be mounted to the magnetic plastic rotor disk by insert m o 1 d 1 n g.
reference t illustrative scope of the changes may departing from the spirit and defined by the appended claims While the invention has been described with o specific embodiments, the description is and is not to be construed as limiting the invention. Various modifications and occur to those skilled in the art without scoDe of the invent!) 5 ( n a z
Claims (3)
- - 13 CLAIMSI. A magnetic plastic rotor disk manufacturing apparatus for manufacturing diametrically magnetized magnetic plastic rotor disks comprising; an injection device for injecting a magnetic plastic material containing a synthetic resin matrix and a magnetic powder; a mold for molding said magnetic plastic material injected thereinto from said injection device, said mold comprising a three-plate type mold constructed of two retainer plates and a single runner stripper plate, one of said retainer plates being formed with a plurality of cavities, while the other retainer plate being formed with a plurality of pin gates corresponding to said cavities so as to supply said magnetic plastic material through said pin gates into said cavities; and means for generating a magnetic field to magnetize said magnetic powder in a direction along a diameter of said magnetic plastic rotor disks.
- 2, The magnetic plastic rotor disk manufacturing apparatus as defined in claim 1, wherein said injection device comprises a screw injection device having a screw head provided with a check valve for preventing backflow of said magnetic plastic material.
- 3, Apparatus according to claim 1, substantially as described with reference to any of the examples shown in Figures 1 to 5 of the accompanying drawings.Published IM at,71he Palent=oe.8tate RouBe,86171 High R01bOm-LOndOn WC1R4TP-FUrtJIerOOPISB maybe ObtalnedfromThefttent EWes Branch, St Mwy Crv, Oryir4ton, Kent BRB MM. Printed by M-ultiPlex techniquOs It'd. St MWY Cray, Kent, CoIL 11870210e.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10416788A JPH01275116A (en) | 1988-04-28 | 1988-04-28 | Rotating plastic magnet manufacturing equipment |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8909713D0 GB8909713D0 (en) | 1989-06-14 |
| GB2217651A true GB2217651A (en) | 1989-11-01 |
| GB2217651B GB2217651B (en) | 1992-03-25 |
Family
ID=14373488
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8909713A Expired - Lifetime GB2217651B (en) | 1988-04-28 | 1989-04-27 | Magnetic plastic rotor disk manufacturing apparatus |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPH01275116A (en) |
| DE (1) | DE3913982C2 (en) |
| GB (1) | GB2217651B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4631521B2 (en) * | 2005-04-25 | 2011-02-16 | 株式会社カネカ | Resin magnet molded product processing method |
| JP4631522B2 (en) * | 2005-04-25 | 2011-02-16 | 株式会社カネカ | Resin magnet molded product processing method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5948742B2 (en) * | 1982-03-05 | 1984-11-28 | 住友ベークライト株式会社 | Mold for magnetic field forming |
| DE3247272A1 (en) * | 1982-12-21 | 1984-06-28 | Krauss-Maffei AG, 8000 München | BACKFLOW LOCK |
-
1988
- 1988-04-28 JP JP10416788A patent/JPH01275116A/en active Granted
-
1989
- 1989-04-27 GB GB8909713A patent/GB2217651B/en not_active Expired - Lifetime
- 1989-04-27 DE DE19893913982 patent/DE3913982C2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE3913982C2 (en) | 1994-02-03 |
| JPH0511739B2 (en) | 1993-02-16 |
| GB2217651B (en) | 1992-03-25 |
| JPH01275116A (en) | 1989-11-02 |
| GB8909713D0 (en) | 1989-06-14 |
| DE3913982A1 (en) | 1989-11-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20050427 |