JP6729872B2 - Annular magnet manufacturing apparatus and annular magnet manufacturing method - Google Patents

Description

The present invention relates to, for example, an annular magnet manufacturing apparatus applied as an encoder for rotation detection and a manufacturing method of the annular magnet by the manufacturing apparatus.

Recently, a magnetic encoder made of an annular resin molded body in which a large number of N poles and S poles are alternately magnetized in the circumferential direction is sometimes used as a rotation detection device for a wheel of a vehicle or an engine. Patent Documents 1 to 4 describe a molding apparatus or a manufacturing method for manufacturing such a magnetic encoder. In Patent Document 1, in a disk gate type molding apparatus for injecting a molten magnet material (molten resin containing magnetic powder) from the entire circumference of the inner peripheral portion of an annular cavity into the cavity, the magnet material is placed in the cavity. It is described that after injection, it is rapidly cooled, solidified and molded. Further, Patent Document 2 also describes a disk gate type molding apparatus, in which a molten resin containing magnetic powder is injected into a cavity, cooled and solidified, and then the mold is opened to take out a molded product. .. Further, Patent Document 3 discloses a molding device of a ring gate (which is synonymous with a disk gate) system, and in this case as well, a molten resin containing magnetic powder in a cavity is cooled and solidified after injection. After that, the mold is opened and the molded product is taken out. The molding apparatuses described in Patent Documents 1 to 3 are all understood to be cold runner type molding apparatuses using a disc gate. On the other hand, Patent Document 4 is similar to the molding devices described in Patent Documents 1 to 3 in that a disk gate is used, but is different in that it is a hot runner system.

JP, 2005-214874, A JP, 2005-108573, A Japanese Patent No. 4682737 JP, 2005-112728, A

By the way, in each of the molding apparatuses described in Patent Documents 1 to 4, since the disk gate is used, there is an advantage that the welded portion is unlikely to be formed in the annular molded product. However, since all of the molding apparatuses described in Patent Documents 1 to 3 are of the cold runner type, there is a problem that the amount of solidified resin remaining in the disk gate portion and the like increases and the yield of the resin material deteriorates. On the other hand, since the molding apparatus described in Patent Document 4 is of the hot runner type, there is little concern that the yield of the resin material will deteriorate even though the disk gate is used. However, in the case of the molding device described in Patent Document 4, the supply passage 16D as one passage is provided at the upper end of the supply passage 16C with respect to the cylindrical supply passages 16B and 16C communicating with the disc gate-shaped supply passage 16A. Connected to the side. Then, the molten resin is introduced from the supply passage 16D into the supply passage 16C and is supplied into the cavity 12 via the supply passages 16B and 16A and the gate 18. Therefore, the molten resin introduced from the supply passage 16D into the annular supply passage 16C is deviated in the annular supply passages 16B and 16C, and in that state, the molten resin passes through the disc-gate-like supply passage 16A and becomes a cavity. It is also expected to be supplied within 12. Therefore, it is considered that even the molding device described in Patent Document 4 cannot eliminate the concern that a welded portion will be formed in the molded product.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a manufacturing apparatus and a manufacturing method for an annular magnet, which can increase the yield of a resin composition used and suppress the generation of weld parts.

An annular magnet manufacturing apparatus according to a first aspect of the present invention is an annular magnet manufacturing apparatus for molding a resin composition containing magnetic powder to manufacture an annular magnet, and an annular cavity and an axis for the cavity. In the direction, a plurality of first runners radially connected to the resin supply sprue, a disk-shaped second runner connected to the plurality of first runners, the second runner and the annular From the resin supply sprue to the disc gate, and a molding die including a disc gate interposed between the inner periphery of the cavity and a gate cut mechanism portion capable of performing a gate cut of the disc gate when the mold is opened. e Bei a heater to keep the resin composition in a molten state, the said second runner, the is formed in a tapered shape so as to extend to the outer peripheral side as it approaches the cavity, the disk gate of the second runner It is characterized in that it is formed so as to be connected to the distal end portion and extend while gradually narrowing the gap so that the peripheral edge portion faces the inner peripheral portion of the annular cavity .

A method for manufacturing an annular magnet according to a second aspect of the present invention is an apparatus for manufacturing an annular magnet using the manufacturing apparatus, wherein the step of clamping the molding die and the heater being turned on are performed. From the resin supply sprue, through the first runner and the second runner, a step of supplying a molten resin composition from the disk gate into the cavity, a step of opening the mold, and remaining in the mold And a step of taking out the semi-finished product.

According to the first and second aspects of the present invention, the disc gate interposed between the second runner and the inner peripheral portion of the annular cavity is gate-cut by the gate cutting mechanism portion when the mold is opened. Since the resin composition from the resin supply sprue to the disc gate is kept in a molten state by the heater, it can be reused as it is, and the yield of the resin composition used can be increased. Further, since the resin composition supplied from the resin supply sprue spreads radially by the radial first runner, the supply pressure of the resin composition can be reduced, and the molding in the cavity can be smoothly performed. Furthermore, since the resin composition is supplied from the disc gate to the annular cavity, it is possible to prevent the weld portion from being generated in the annular resin molded product.

In the first invention, the molding die includes a first main die aligned with an end surface of the annular magnet, and a first core that is provided with the disk gate and moves prior to the first main die when the die is opened. And a second mold that forms the cavity in a united portion with the first mold, the gate cut mechanism portion, when the mold is opened the first main mold and the first core The gate may be cut by the shearing force generated by the difference in movement.
According to the present invention, since the gate cut is performed by the shearing force generated by the movement difference between the first main mold and the first core when the mold is opened, it is possible to suppress the generation of unevenness on the surface of the gate trace. ..

In the first invention, the second runner-side openings of the plurality of first runners may be spiral in the axial direction and arranged at equal intervals around the axial direction .
According to the present invention, the opening area of the second runner side openings in the plurality of radially extending first runners is ensured as compared with the second runner side openings in the first runner formed parallel to the axial direction. be able to. Therefore, the supply pressure of the resin composition can be further reduced accordingly.

1st invention WHEREIN: It arrange|positions so that the said shaping|molding die may be pinched|interposed in the said axial direction, and is equipped with the exciting coil for orienting the said magnetic powder in the said resin composition supplied to the said cavity. May be
According to the present invention, magnetic properties such as magnetic force of the obtained annular magnet can be improved by orienting the magnetic powder contained in the resin composition in the cavity by the exciting coil during molding.
In this case, the magnetic field path portion sandwiching the cavity in the molding die between the exciting coils may be made of magnetic metal.
According to this, the magnetic flux generated from the exciting coil during molding easily passes through the cavity, and the degree of orientation of the magnetic powder in the molded product can be increased.

In the first invention, the cavity is capable of holding a metal ring with one surface thereof being exposed in the cavity, and the molding die has a positioning structure portion for positioning the metal ring at a predetermined position of the cavity. You may be doing it.
According to the present invention, an annular magnet integrated with a metal ring can be molded with the metal ring inserted in a predetermined position of the cavity.

2nd invention WHEREIN: In parallel with the process of arrange|positioning an exciting coil so that the said shaping|molding die may be pinched|interposed in the said axial direction, and supplying a resin composition in the said cavity, by the said exciting coil, in the said cavity The step of orienting the magnetic powder in the resin composition supplied to the magnetic field in a magnetic field may be further added.
According to the present invention, the magnetic field generated by the exciting coil may be configured to act on the annular body formed by the cavity along the axial direction of the annular body. According to this, since the magnetic powder is oriented along the axial direction, when the obtained molded body is magnetized into an axial type magnetic encoder, the magnetization is extremely effectively performed.

According to the annular magnet manufacturing apparatus and manufacturing method of the present invention, it is possible to increase the yield of the resin composition used and suppress the occurrence of weld parts.

It is a schematic longitudinal cross-sectional view showing an example of an annular magnet manufacturing apparatus according to the present invention. It is the XX sectional view taken on the line in FIG. (A) (b) (c) is a process drawing which shows an example of the manufacturing method of the annular magnet which concerns on this invention in the part corresponding to the Y section of FIG. 1, (a) is a process of arranging a metal ring in a cavity (B) shows the step of clamping the first die and the second die, and (c) shows the step of supplying the molten resin to the cavity. (A) (b) (c) shows the next process of the same process and subsequent processes, (a) shows the state where the gate was cut in the mold opening process, and (b) shows the state where the mold opening is completed, respectively. It is a figure similar to FIG. 3, and (c) shows a partially broken vertical sectional view of the annular magnet obtained after the step of taking out from the molding die.

Embodiments of the present invention will be described below with reference to FIGS. In the cross-sectional view, the cross-hatched portion is shown to be made of a magnetic material, and the normal hatched portion is shown to be made of a non-magnetic material.
FIG. 1 and FIG. 2 show that the annular magnet manufacturing apparatus according to the present invention is a magnetic field molding apparatus 1. The magnetic field molding apparatus 1 of the present embodiment includes a fixed plate 2 and a movable plate 4 which is provided to the fixed plate 2 so as to be able to approach and separate from each other in the vertical direction via four magnetic tie bars 3. A magnetic field molding die (molding die) 5 interposed between the fixed platen 2 and the movable platen 4, and a heater 8. The fixed platen 2 and the movable platen 4 as the mold supporting platen may be configured such that the fixed and movable relationships are reversed, or both are movable so that they can move toward and away from each other. An exciting coil 200 is embedded in the fixed platen 2. An exciting coil 400 is embedded in the movable platen 4.

The molding die 5 includes an annular cavity 50, a resin supply sprue 51 extending in the direction of the axis L with respect to the cavity 50, and a plurality of (16 in the example shown in FIG. 2) radially connected to the resin supply sprue 51. The first runner 52, the disk-shaped second runner 53 connected to the plurality of first runners 52, and the disk gate 54 interposed between the second runner 53 and the inner peripheral portion 50a of the annular cavity 50. And a gate cut mechanism portion 55 that can cut the gate of the disk gate 54 when the mold is opened. In this embodiment, the resin supply sprue 51, the disc-shaped second runner 53, the disc gate 54, and the annular cavity 50 are formed so as to be coaxial with the axis L. More specifically, the molding die 5 is provided with an annular first main die 61 aligned with the end face of an annular magnet (see FIG. 4C) 9 described later, and a disc gate 54, and at the time of die opening. A first die 6 including a first core 62 that moves prior to the one main die 61, and a second die 7 that forms a cavity 50 in a united portion with the first die 6 are provided. The gate cutting mechanism 55 in the present embodiment is configured to perform gate cutting by a shearing force generated by a movement difference between the first main mold 61 and the first core 62 when the mold is opened. Further, the first mold 6 is provided with a plurality of heaters 8 for keeping the resin composition r (see FIG. 4A) from the resin supply sprue 51 to the disc gate 54 in a molten state at appropriate intervals around the axis L. It is buried.

The first mold 6 includes, in addition to the first main mold 61, an annular second main mold 61A integrated with the upper end of the first main mold 61, and a compression spring 63 in the second main mold 61A. It has the connected 3rd main model 61B of the cyclic|annular form. The first main mold 61, the second main mold 61A, the compression spring 63, and the third main mold 61B are made of magnetic metal. In addition to the first core 62, the first mold 6 includes a second core 62A coaxially screw-coupled to the lower recess 62a of the first core 62, and the second core 62A. It has a third core 62B coaxially screwed to the lower cylindrical portion 62Ab. Reference numeral 62b indicates a screw connection portion between the first core 62 and the second core 62A, and reference numeral 62Ac indicates a screw connection portion between the second core 62A and the third core 62B. The first core 62, the second core 62A and the third core 62B are made of a non-magnetic material. A fourth core 62C made of a non-magnetic material is provided above the first core 62 and on the inner peripheral side of the third main mold 61B. An upper die base 65 made of magnetic metal is integrally provided on the upper ends of the third main die 61B and the fourth core 62C via a spacer member 64. The spacer member 64 is composed of a non-magnetic disc portion 64a having an insertion hole 64aa into which a nozzle of an injection device (not shown) is inserted, and an annular disc portion 64b made of a magnetic substance metal and integrated with the outer peripheral portion thereof. Become. The upper mold base 65 and the movable platen 4 are also provided with insertion holes (not shown) into which the nozzles of the injection device are inserted. The circular ring portion 64b closely intervenes between the upper end of the third main mold 61B and the upper mold base 65. The upper mold base 65 is a plate-shaped body having a size overlapping a part of the exciting coil 400 provided on the movable platen 4. The first main mold 61 and the second main mold 61A are configured so as to be in a fitting relationship capable of sliding along the axis L direction with respect to the first core 62. The slidable fitting relationship between the first main mold 61 and the first core 62 constitutes a gate cut mechanism unit 55 described later.

The resin supply sprue 51 is provided coaxially with the axis L at the center of the first core 62 and the second core 62A, and its upper end is joined to a nozzle of an injection device (not shown). Further, in the middle portion 62Aa along the axis L direction of the second core 62A, the lower end portion of the resin supply sprue 51 extends in the direction orthogonal to the axis L, and is circumferentially equidistant over 360 degrees. A plurality of first runners 52 that are radially connected are provided. The first runners 52... Are in communication with the resin supply sprue 51 through an opening 52a on the resin supply sprue 51 side. The middle part 62Aa of the second core 62A provided with the first runners 52 has a truncated cone shape, and the side face 61Ab of the middle part 62Aa has an opening 52b on the second runner 53 side of each first runner 52. Are formed. The openings 52b on the second runner 53 side of the first runner 52 are spiral in the direction of the axis L and are arranged at equal intervals around the axis L. The openings 52b... Of each of the first runners 52 are formed in an oblong shape in a front view. The second runner 53 is formed by a disc-shaped gap between the side surface 61Ab of the intermediate portion 62Aa of the second core 62A and the tapered inner peripheral surface of which the diameter of the first core 62 is expanded downward. The second runner 53 is formed so as to extend toward the outer peripheral side as it approaches the cavity 50, in other words, it is formed into a trumpet shape. Further, the disk gate 54 is a gap between the first core 62 and the third core 62B, is connected to the tip end portion of the second runner 53, and extends while gradually narrowing the gap, and the peripheral edge portion 54a has the cavity 50. Is formed so as to face the inner peripheral portion 50a.

The second die 7 is made of a magnetic metal and forms an annular cavity 50 together with the first die 6 in the united portion with the first die 6. The second die 7 is integrally provided on a lower die base 66 made of magnetic metal. The lower mold base 66 is a plate-shaped body having a size overlapping a part of the exciting coil 200 provided on the fixed platen 2. The outer diameter of the outer peripheral portion 7a of the second die 7 on the cavity 50 side is substantially the same as or slightly smaller than the inner diameter of the cylindrical portion 9a of the metal ring 9 described later. Further, the first main mold 61 and the second main mold 61A in the first mold 6 are integrally fitted with the cylindrical auxiliary mold 10 having the flange portion 10a extending inward (toward the axis L). ing. The auxiliary mold 10 is made of a non-magnetic metal material. The flange portion 10a has a positioning structure for positioning the inner periphery 10aa of the flange 50a in a predetermined position so as to define the outer shape of the cavity 50 and hold the metal ring 9 with one surface thereof exposed in the cavity 50. Make up the department.

A method for manufacturing an annular magnet by using the magnetic field molding apparatus 1 as an annular magnet manufacturing apparatus configured as described above will be described with reference to FIGS. 3 and 4. First, the first die 6 is fixed to a predetermined position on the lower surface of the movable platen 4 by a jig (not shown), and the second die 7 is similarly fixed to a predetermined position on the upper surface of the fixed platen 2. In the fixed state of the first die 6 and the second die 7, the upper surface of the upper die base 65 is in contact with the lower surface of the movable platen 4. Further, in the fixed state of the first die 6 and the second die 7, the lower surface of the lower die base 66 is in contact with the upper surface of the stationary platen 2. At the same time, a molten thermoplastic resin and anisotropic magnetic powder such as ferrite are mixed at a predetermined ratio to prepare a resin composition r, and the resin composition r is filled in an injection device (not shown). Then, the metal ring 9 is arranged at a predetermined position in the cavity 50. The metal ring 9 includes a cylindrical portion 9a and a flange-shaped disc portion 9b formed inward (toward the axis L side) from one end of the cylindrical portion 9a. The metal ring 9 is arranged such that the cylindrical portion 9a is fitted to the outer peripheral portion 7a of the second die 7 and the disc portion 9b is placed on the upper end surface 7b of the second die 7. With the metal ring 9 arranged in this manner, the one surface 9ba of the disk portion 9b and the inner peripheral surface 9bb (one surface of the metal ring 9) are exposed in the cavity 50 (FIG. 3(a) ( See b)).

The movable platen 4 is lowered by an elevating device (not shown), and the first die 6 is united with the second die 7 as shown in FIGS. 1 and 3(b) to perform die clamping (die clamping step). This mold clamping is performed in a state in which the compression spring 63 is compressed, and by this mold clamping, the cavity 50 forms the first core 62 and the third core 62B of the first mold 6 and the upper end surface of the second mold 7. 7b and the inner peripheral portion 10aa of the auxiliary mold 10 are formed as a space. Further, by this mold clamping, the metal ring 9 is held with its one surfaces 9ba, 9bb exposed in the cavity 50. In this holding state, the flange portion 10a of the auxiliary die 10 elastically abuts on the disk portion 9b of the metal ring 9, and this elastic abutment stabilizes the metal ring 9 at a predetermined position without moving upward. Be positioned at. Further, by this mold clamping, the disc gate 54 is positioned so that the peripheral edge portion (gate end) 54a thereof faces the inner peripheral portion 50a of the annular cavity 50.

When the mold clamping step is completed as described above, the step of supplying the resin composition is performed. In the step of supplying the resin composition, first, the heater 8 is turned on and the molten resin composition r is supplied to the sprue 51 by an injection device (not shown) while maintaining the first mold 6 at a predetermined temperature. .. Further, the resin composition r in a molten state is injected and supplied from the sprue 51 through the first runner 52... And the second runner 53 into the cavity 50 from the disk gate 54 (FIG. 3(c)). From the sprue 51 coaxial with the axis L, a plurality of first runners in which a molten resin composition r extends in a direction orthogonal to the axis L and are radially connected at equal intervals in the circumferential direction over 360 degrees. 52 is supplied to each of the first runners 52, the resin composition r is supplied substantially evenly. Then, the resin composition r is supplied to the disk-shaped second runner 53 from the opening 52b of the first runner 52 on the side of the second runner 53, where it is equalized and supplied to the disk gate 54. In particular, since the openings 52b on the second runner 53 side have a spiral shape in the axis L direction and are arranged at equal intervals around the axis L, the resin composition r in the second runner 53 Equalization is made more reliable. Since the resin composition r is supplied to the disk gate 54 in a circumferentially uniformed state, the resin composition r is supplied to the cavity 50 from the gate end 54a of the disk gate 54 along the circumferential direction of the inner peripheral portion 50a. Supplied evenly. As a result, there is no concern that a welded part will be formed in the molded product.

In the present embodiment, a step of magnetic field orientation of the magnetic powder is performed in parallel with the step of supplying the resin composition. In the main magnetic field orientation step, the exciting coils 200 and 400 are energized to form a predetermined magnetic field a (see FIGS. 1 and 3C) in the magnetic field molding apparatus 1. The magnetic field a is applied from the upper excitation coil 400 to the movable platen 4, the upper mold base 65, the circular ring portion 64b of the spacer member 64, the third main mold 61B, the second main mold 61A, the first main mold 61, the metal ring. A loop-shaped magnetic field path is formed to reach the exciting coil 400 through the cavity 50 including the cavity 9, the second mold 7, the lower mold base 66, the fixed platen 2, the tie bar 3, and the movable platen 4. Due to this magnetic field a, the magnetic powder contained in the resin composition r supplied into the cavity 50 is oriented in one direction. Since all the members along the loop-shaped magnetic field path are made of magnetic metal, the magnetic field a generated from the exciting coils 200 and 400 easily passes through the cavity 50 in a state where the magnetic flux density is high. The degree of orientation of the magnetic powder in the product can be increased.

When the step of supplying the resin composition and the step of orienting the magnetic powder are completed as described above, the step of opening the molding die is performed. At the time of opening the mold, first, while the heater 8 is kept on, the supply of the resin composition from the injection device is stopped and the movable platen 4 is raised. In the initial stage of raising the movable platen 4, the third main mold 61B, the first core 62, the second core 62A, the third core 62B and the fourth core 62C are integrally raised. At this time, the first main mold 61, the second main mold 61A and the auxiliary mold 10 are kept stationary by the downward elasticity of the compression spring 63. Therefore, the first core 62 ascends together with the third core 62B while slidingly contacting the fitting portion with the first main mold 61. As a result, a shearing force is generated between the gate end 54a of the disc gate 54 and the inner peripheral portion 50a of the cavity 50 due to the movement difference between the first main mold 61 and the first core 62, and the cavity 50 and the disc gate The molten resin composition r existing between 54 is cut at this portion (see FIG. 4A). In the present embodiment, the gate cut mechanism unit 55 is configured by a mechanism that generates a shearing force due to a movement difference between the first main mold 61 and the first core 62 via the compression spring 63. With such a gate cut mechanism portion 55, it is possible to suppress the generation of irregularities on the surface of the gate trace. Further, the gate cut mechanism portion 55 that functions at the time of mold opening can be configured only by interposing the compression spring 63 between the second main mold 61A and the third main mold 61B, and the device can be made compact and the manufacturing process can be improved. The efficiency of can be improved.

After the gate is cut, when the movable platen 4 further rises, the compression spring 63 extends, and when the compression spring 63 reaches the extension limit, the compression spring 63 causes the first main mold 61, the second main mold 61A and the auxiliary mold. 10 is pulled up. As a result, as shown in FIG. 4B, the semi-finished product 11 in which the resin composition r is integrally formed as an uncured molded product on the one surface 9ba, 9bb of the metal ring 9 remains on the second mold 7, This completes the mold opening process. Thereafter, the semi-finished product 11 is cooled on the second mold 7 to cure the resin composition r in a molten state, and the resin molded product 12 is integrated with the metal ring 9 as shown in FIG. 4(c). The annular magnet 13 is removed from the molding die (second die 7) 5 (step of taking out). Since the heater 8 is kept in the ON state, the resin composition r remaining on the resin supply sprue 51, the first runner 52, the second runner 53, and the disk gate 54 is kept in a molten state. Therefore, the above step can be continuously started to manufacture the next annular magnet 13, whereby the efficient manufacture of the annular magnet 13 can be carried out, and the resin composition r can be used without waste. Therefore, the product yield can be improved.
It is also possible to remove the semi-finished product from the second mold 7 and then cure it to obtain the annular magnet 13 as a product.

In the ring-shaped magnet 13 obtained as described above, the ring-shaped resin molded product 12 is a homogeneous one having no weld portion in the circumferential direction, and the magnetic powder contained in the resin molded product 12 is Most are oriented in the thickness direction (direction along the axis L). Therefore, when the present annular magnet 13 is applied as a magnetic encoder, multi-pole magnetization is effectively performed on the surface thereof, whereby a rotation detecting mechanism with high accuracy can be configured. The magnetic encoder in which the annular magnet 13 is thus multi-polarized is, for example, attached to a rotating side member (inner ring or the like) of a bearing device for a wheel of an automobile via a metal ring 9, and a fixed side member (outer ring, A wheel rotation detection mechanism can be configured by installing a magnetic sensor on a vehicle body or the like) so as to face the multipolar magnetized surface.

The gate cut mechanism portion 55 in the above embodiment is configured by a mechanism that generates a shearing force due to a movement difference between the first main mold 61 and the first core 62 via the compression spring 63, but is not limited to this. Absent. For example, in a gate cut mechanism that does not provide the compression spring 63, the first main mold 61 and the first core 62 move together when the mold is opened, and the disk gate 54 naturally separates from the annular magnet 13 to perform a gate cut. good. Further, as long as the openings 52b on the second runner 53 side of the first runner 52 are spiral, the shape of the other parts of the first runner 52 is not particularly limited. For example, the shape of the first runner 52 is formed so as to extend in the direction orthogonal to the axis L direction from the opening 52a on the resin supply sprue 51 side to the middle of the opening 52b on the second runner 53 side. Good. Further, the opening 52b of the first runner 52 on the second runner 53 side is not limited to a spiral shape, and may be an opening parallel to the axis L direction, or may be arranged around the axis L at unequal intervals. Good.

Further, in the above-described embodiment, an example in which the heater 8 is embedded in the first mold 6 is shown, but the present invention is not limited to this, and the resin composition r from the resin supply sprue 51 to the disc gate 54 can be kept in a molten state. If possible, it is not excluded to provide the heater 8 by a method other than embedding. Further, although the example in which the resin supply sprue 51 is coaxial with the annular cavity 50 is shown, the resin supply sprue 51 may be provided at a position eccentric to the cavity 50. Furthermore, although the example in which the metal ring 9 and the resin molded product 12 are integrated into the annular magnet 13 has been described, the annular magnet 13 may be composed of only the resin molded product 12. Further, the example in which the disk portion 9b of the metal ring 9 constituting the annular magnet 13 is formed inward has been described, but it is formed outward (toward the centrifugal side with respect to the axis L). May be. In addition, when the magnetic field orientation is not required, the exciting coil is not required, and each component (movable plate 4, upper die base 65, circular ring portion 64b of the spacer member 64, The three main molds 61B, the second main mold 61A, the first main mold 61, the second mold 7, the lower mold base 66, the fixed platen 2 and the tie bar 3) may be made of a non-magnetic material. In addition, the configuration and shape of each part of the manufacturing apparatus 1 can be changed to other configurations and shapes without departing from the present invention.

1 Magnetic field molding equipment (manufacturing equipment)
5 Molding Dies 50 Cavities 50a Inner Circumference 51 Resin Supply Sprue 52 First Runner 52b Second Runner Side Opening 53 Second Runner 54 Disk Gate 55 Gate Cut Mechanism 6 First Die 61 First Die 62 First Die 7 Second type 8 Heater 9 Metal ring 9ba One side of disk part (one side)
9bb Inner surface of disc (one side)
10 Auxiliary type (positioning structure part)
11 semi-finished product 13 annular magnet 200,400 exciting coil a magnetic field L axis

Claims (8)

A ring magnet manufacturing apparatus for manufacturing a ring magnet by molding a resin composition containing magnetic powder,
An annular cavity, a resin supply sprue extending in the axial direction with respect to the cavity, a plurality of first runners radially connected to the resin supply sprue, and a disk-shaped first runner connected to the plurality of first runners. A molding die including two runners, a disc gate interposed between the second runner and the inner peripheral portion of the annular cavity, and a gate cutting mechanism portion capable of performing a gate cut of the disc gate when the mold is opened, ,
E Bei and a heater to keep the resin composition from the resin supply sprue until the disk gate in a molten state,
The second runner is formed in a tapered shape so as to extend to the outer peripheral side as it approaches the cavity,
The disc gate is connected to the tip of the second runner, and extends while gradually narrowing the gap so that its peripheral edge faces the inner peripheral portion of the annular cavity. Ring magnet manufacturing equipment. The annular magnet manufacturing apparatus according to claim 1,
The molding die is a first die including a first main die that is aligned with an end surface of the annular magnet, and a first die that is provided with the disk gate and moves prior to the first main die when the die is opened. A second mold for forming the cavity in a united portion with the first mold,
The apparatus for manufacturing an annular magnet, wherein the gate cutting mechanism section performs gate cutting by a shearing force generated by a difference in movement between the first main mold and the first core when the mold is opened. The manufacturing apparatus of the annular magnet according to claim 1 or 2,
The second runner side openings of the plurality of first runners are spiral in the axial direction and are arranged at equal intervals around the axial direction . The manufacturing apparatus of the annular magnet according to any one of claims 1 to 3,
An annular magnet, which is arranged so as to sandwich the molding die in the axial direction, and is provided with an exciting coil for orienting the magnetic powder in the resin composition supplied to the cavity. Manufacturing equipment. The manufacturing apparatus of the annular magnet according to claim 4,
An annular magnet manufacturing apparatus, wherein a magnetic field path portion sandwiching the cavity in the molding die between the exciting coils is made of magnetic metal. The manufacturing apparatus of the annular magnet according to any one of claims 1 to 5,
The cavity is capable of holding a metal ring in a state where one surface of the metal ring is exposed in the cavity, and the molding die has a positioning structure that positions the metal ring at a predetermined position of the cavity. Manufacturing device for annular magnet. A method for producing an annular magnet, which is produced using the apparatus for producing an annular magnet according to any one of claims 1 to 6,
A step of clamping the molding die,
From the resin supply sprue in a state where the heater is turned on, a step of supplying a molten resin composition from the disk gate into the cavity through the first runner and the second runner,
A step of opening the molding die,
A step of removing the semi-finished product remaining in the mold ,
A method of manufacturing an annular magnet, comprising: The method for manufacturing an annular magnet according to claim 7,
An exciting coil is arranged so as to sandwich the molding die in the axial direction,
In parallel with the step of supplying the resin composition into the cavity, a step of magnetically orienting the magnetic powder in the resin composition supplied into the cavity by the exciting coil is further added. Manufacturing method of annular magnet.

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