JPH0864451A - Method and device for chamfering an arc-shaped ferrite magnet - Google Patents

Abstract

(57) [Abstract] [Purpose] Prevents the generation of cracks and chips that were generated when surface mounting was performed in another process by chamfering the molded body for bow-shaped ferrite magnets before firing. To improve yield and reduce chamfering cost. [Structure] When chamfering an arcuate ferrite magnet, a chamfered portion is formed from rotary grindstones 50A and 50B at an outer peripheral edge 35 of the arcuate ferrite magnet molding 30 before firing. To do. As a result,
It is possible to improve the product yield by preventing the occurrence of cracks and chips in the subsequent process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for chamfering an arc-shaped ferrite magnet (C-shaped ferrite magnet) which is mainly used for small motors for automobiles.

[0002]

2. Description of the Related Art FIG. 13 shows an example of an arc-shaped ferrite magnet (C-shaped ferrite magnet) used in a small motor for an automobile or the like, which is not chamfered.
In the figure, reference numeral 1 is an arcuate ferrite magnet obtained by molding and sintering ferrite magnetic powder in an arc shape which is a part of a cylinder, and is a part of a cylinder having an outer peripheral surface 2 and an inner peripheral surface 3 as shown in FIG. It has a certain arcuate shape, and both axial end surfaces 4 are flat surfaces orthogonal to the outer peripheral surface 2 and the inner peripheral surface 3.

Conventionally, as shown in FIG. 14, an outer peripheral edge 6 (outer peripheral surface 2 and an outer peripheral surface 2) is formed in the pre-finishing process before magnetizing the arc-shaped ferrite magnet 1 fired without chamfering as shown in FIG. The chamfered portion 5 is formed by polishing with a grindstone on the boundary portion with the end face 4 in the axial direction (Japanese Patent Laid-Open No. 5-129129 proposed by the present applicant discloses a similar chamfering method). .). The reason for this chamfering is to prevent the sharp edges from being chipped when the molded bodies and the fired bodies come into contact with each other, and to improve workability when incorporating them into a case (housing) such as a motor or to make an arc-shaped ferrite. This is because it serves as an adhesive reservoir when the magnet and the case are bonded with an adhesive, and is usually attached to the edge 6 of the outer circumference of the magnet in a size of about C1 (1 mm in the radial direction of the magnet, 1 mm in the axial direction). Although FIG. 14 shows that the chamfered portion 5 is formed only on one outer peripheral edge, the chamfering is usually performed on both outer peripheral edges of the arc-shaped ferrite magnet.

FIGS. 15 to 17 show a conventional apparatus for chamfering the arcuate ferrite magnet 1 after firing. Reference numeral 10 is an entrance conveyor, 11 is an exit conveyor, and 12A and 12B are index tables. The index tables 12A and 12B that rotate intermittently as shown by arrows in the drawing have fixing jigs 14 that fix the arcuate ferrite magnets 1 at equal angular intervals (for example, 45 ° intervals).

As shown in FIGS. 16 and 17, a fixing jig 1 fixed on the index tables 12A and 12B.
Reference numeral 4 denotes a stopper 15 fixed to the index tables 12A and 12B so as to come into contact with one end surface 4 of the arc-shaped ferrite magnet 1 in the axial direction, and a holding arm 16 pivotally supported on the index tables 12A and 12B side at a fulcrum a. , And an air cylinder 17 for driving the pressing arm 16. Therefore, the fixing jig 14 holds the bow-shaped ferrite magnet 1 by pressing it from above with the holding arm 16 operated by the air cylinder 17 as shown in FIGS. 16 and 17 except when the bow-shaped ferrite magnet 1 is received and sent out. ing.

As shown in FIG. 15, rotary whetstones 13A and 13B are arranged to polish the arcuate ferrite magnet 1 that has reached the polishing positions of the index tables 12A and 12B. Here, the index table 12
The rotation center axis b of A and 12B does not move, and the rotation grindstone 13
The rotation center axis d of A and 13B moves.

In the conventional apparatus for chamfering the fired arcuate ferrite magnet 1 as described above, the fired arcuate ferrite magnet 1 reaching the tip by the entrance side conveyor 10 traveling as shown by an arrow e in FIG. It is sent by a pusher (not shown) to the fixing jig 14 on the index table 12A at the position f stopped at the position facing the tip of the entrance conveyor 10, and is sent to the polishing position h by the intermittent rotation of the index table 12A. A chamfered portion is formed by a rotating grindstone 13A on one outer peripheral edge of the arc-shaped ferrite magnet 1 held by the fixing jig 14 at the polishing position h. After that, the arcuate ferrite magnet 1 is sent to the position j by the intermittent rotation of the index table 12A, and the fixing jig 14 on the index table 12B shown in FIG. Not transferred by pusher. And the index table 12
By the intermittent rotation of B, the chamfered portion is formed by the rotating grindstone 13B on the other outer peripheral edge of the arc-shaped ferrite magnet 1 which is sent to the polishing position m and held by the fixing jig 14 at the position m. The arc-shaped ferrite magnets 1 whose surface mounting on both outer peripheral edges has been completed are sent to the position n by intermittent rotation of the index table 12B, where they are sent to the exit side conveyor 11 by a pusher (not shown) and sent to the next step. .

On the other hand, as shown in FIG. 18, when the ferrite magnetic powder is molded into an arc shape by a lower mold 21 that moves up and down in the die 20 and an upper mold 22 that can move up and down, the upper mold 22 has a chamfered portion 23 beforehand. It has been conventionally practiced to form a chamfered portion on the outer peripheral side edge at the same time that the arc-shaped ferrite magnet molded body is molded.

[0009]

By the way, in the conventional chamfering method of chamfering the outer peripheral edge of the arc-shaped ferrite magnet after firing, a sharp corner is formed between the molding process and the firing process during handling by a device or a person. There is a problem that chipping is likely to occur and chamfering after firing increases the cost of the grindstone.

Further, the chamfering of the outer peripheral edge at the time of molding with a conventional mold has a tendency that cracks are generated in the molded body from the mating portion of the mold at the time of molding, which lowers the yield.

Since the bowed ferrite magnet molded body before firing is more brittle than that after firing, there is a problem that cracks and chips occur when the conventional chamfering device is used for the molded body before firing. It was Therefore, the chamfering of the molded body before firing has not been conventionally performed.

In view of the above points, the present invention occurs when surface mounting is performed in the conventional molding step or the step after firing by chamfering the bow ferrite magnet shaped body before firing. It is an object of the present invention to provide a method and an apparatus for chamfering an arc-shaped ferrite magnet, which can prevent the occurrence of cracks and chips, which has been caused, and improve the yield.

Other objects and novel features of the present invention will be clarified in Examples described later.

[0014]

In order to achieve the above object, a method for chamfering an arc-shaped ferrite magnet according to the present invention is a method for chamfering an arc-shaped ferrite magnet formed by firing a molded body for an arch-shaped ferrite magnet, before firing. In the step of the above-mentioned molded body for an arc-shaped ferrite magnet, a chamfered portion is formed by a rotary grindstone or a rotating brush on the outer or inner edge of the molded body for the arc-shaped ferrite magnet.

The chamfered portion may be formed by polishing along the length direction of the outer peripheral surface or the inner peripheral surface of the bow-shaped ferrite magnet molded body.

Further, the chamfering device of the bow-shaped ferrite magnet of the present invention comprises a mounting table on which the molded body for the bow-shaped ferrite magnet before firing is mounted, and a fixing means for fixing the molded body for the bow-shaped ferrite magnet on the mounting table. And a central axis of rotation of the arc-shaped ferrite magnet molded body which is capable of contacting at least the entire region of the outer or inner peripheral edge of the arc-shaped ferrite magnet molded body and which is perpendicular to the axial direction of the bow-shaped ferrite magnet molded body. A cylindrical rotating grindstone or a rotating brush that rotates around the center, and a moving means that changes the relative positional relationship between the rotating grindstone or the rotating brush and the mounting table, and the axial direction of the arched ferrite magnet molded body. The polishing surface of the rotary grindstone or the rotary brush is brought into contact with the end surface of the above so as to form an acute angle of 30 to 60 °, and the edge of the outer circumference or the inner circumference is polished.

Incidentally, at a position where it can contact the rotary grindstone,
A rotating brush for preventing clogging may be provided to remove cutting powder that has entered the eyes of the abrasive grains of the rotating grindstone.

The mounting table may have an arcuate surface capable of contacting substantially the entire inner peripheral surface or the outer peripheral surface of the bow-shaped ferrite magnet molded body.

[0019]

In the method and apparatus for chamfering an arc-shaped ferrite magnet according to the present invention, a chamfered portion is formed on the outer or inner edge of the arc shape with a rotating grindstone or a rotating brush with respect to the molded article for an arc-shaped ferrite magnet before firing. Since the subsequent firing process and the finish grinding process for the inner and outer peripheral surfaces of the arc-shaped ferrite magnet after firing are performed with chamfering, it is possible to reduce the occurrence of chips during handling by the device or person. .

In the chamfering method of the bow-shaped ferrite magnet of the present invention, when the chamfered portion is formed by polishing along the length direction of the outer peripheral surface or the inner peripheral surface of the molded body for the bow-shaped ferrite magnet, the bow-shaped ferrite magnet It is possible to use a cylindrical rotating grindstone or rotating brush that rotates around a central axis of rotation that is perpendicular to the axial direction of the molded body for use, and a rotating grindstone or rotating brush that can contact a wide range of the outer or inner peripheral edge. The chamfering process can be efficiently performed by using, and a more efficient chamfering process can be performed by using a rotating grindstone or a rotating brush that can contact the entire region where the chamfering of the outer peripheral edge or the inner peripheral edge is necessary.

In the chamfering device for an arcuate ferrite magnet according to the present invention, the chamfered edge of the arcuate ferrite magnet molding can be efficiently chamfered at an appropriate angle (30 to 60 °).

Further, a rotary grindstone is used in a chamfering device of the arc-shaped ferrite magnet, and a rotary brush for preventing clogging for removing the cutting powder that has entered the eyes of the abrasive grains of the rotary grindstone at a position where it can contact the rotary grindstone. When the above is provided, the usable period of the rotary grindstone can be extended, and the number of times of exchanging the rotary grindstone can be reduced.

When the mounting table has an arc surface capable of contacting substantially the entire inner peripheral surface or the outer peripheral surface of the bow-shaped ferrite magnet molded body, the molded body is prevented from cracking and chamfered. The processing can be surely executed.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method and apparatus for chamfering an arc-shaped ferrite magnet according to the present invention will be described below with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIGS. The first embodiment shows a case where the outer peripheral edge of an arcuate (C-shaped) ferrite magnet molded body before firing is chamfered. Here, in the bowed ferrite magnet molded body 30 to be processed, which is not yet fired, a slurry in which ferrite magnetic powder is suspended in a dispersion medium such as water is pressure-fed and filled into a molding space of a molding apparatus, and is pressurized in a magnetic field. At the same time, it is a wet-molded product molded while removing the dispersion medium from the molding space. The shape of the arc-shaped ferrite magnet molded body 30 of this wet-molded product is the same as that shown in FIG. 13, for example, and is formed by molding ferrite magnetic powder into a bow shape that is a part of a cylinder, and has an outer peripheral surface 32. It has a bow shape that is a part of a cylinder having an inner peripheral surface 33 and an axially opposite end surface 34 and an outer peripheral surface 32 and an inner peripheral surface 3.
It is a flat surface orthogonal to 3 and. For example, the outer radius of the arc-shaped ferrite magnet molded body 30 is 20 mm, the inner radius is 13 mm, the lateral width is 27 mm, the length is 23 mm, etc., and various inner and outer diameters, lateral widths, and lengths are used depending on the application. .

FIGS. 1 and 2 show the construction of the main part of the first embodiment, and FIG. 3 shows the overall construction of the first embodiment. In the overall configuration of FIG. 3, reference numeral 40 denotes, for example, a belt conveyor that travels in a horizontal plane, and transfers the pre-fired arcuate ferrite magnet molded body 30 in the X direction. Two moving tables 41A and 41B along the belt conveyor 40
Is provided. These moving tables 41A, 41
B is a main body portion 42A, 42B and a main body portion 42A, 42B
On the other hand, a molded body mounting table 43 that can be linearly moved back and forth in the Y direction
A and 43B. The main body portions 42A and 42B are fixed to the floor surface on which the belt conveyor 40 is installed, but the molded body mounting bases 43A and 43B are movable tables in the Y direction in a horizontal plane orthogonal to the traveling direction (X direction) of the belt conveyor 40. The drive mechanism (air cylinder) inside 41A and 41B can move.

As shown in FIGS. 1 and 2, the molded body mounting bases 43A and 43B of the moving tables 41A and 41B are provided.
Is an arc surface 44 capable of contacting substantially the entire inner peripheral surface 33 of the arcuate ferrite magnet molded body 30, a stopper 45 with which one (front) end surface 34 of the arcuate ferrite magnet molded body 30 abuts, The first chuck 4 for pressing one end surface 34 of the ferrite magnet molded body 30 against the stopper 45.
6 and a second chuck 47 that presses the bow-shaped ferrite magnet molded body 30 from above. Here, the second
The chuck 47 has a function of preventing two pieces of the outer peripheral surface 32 of the arcuate ferrite magnet molded body 30 from being pressed against the circular arc surfaces 44 of the molded body mounting bases 43A and 43B from above. These stopper 45, chucks 46, 47
Constitutes a fixing means for the molded body.

As shown in FIGS. 1 and 3 to 6, the rotary grindstones 50A and 50B for chamfering have a rotation center axis 51 in the X direction orthogonal to the axial direction of the arcuate ferrite magnet molded body 30. It is a generally cylindrical shaped grindstone in which all the circumferentially supported surfaces are grindstones, and the cylindrical circumferential surface 52 is in contact with at least the entire area of the arcuate ferrite magnet molded body 30 that requires chamfering. . In this case, the central portion of the peripheral surface 52 on the grindstone side forms an angle θ (approximately 4) with respect to the axial end surface 34 of the arcuate ferrite magnet molded body 30 as shown in FIG. 6.
5 °) forming an edge 35 on the outer periphery of the arcuate ferrite magnet molded body 30 (a boundary portion between the outer peripheral surface 32 and the end surface 34).
The axial cross section of the rotary grindstones 50A and 50B corresponds to the outer peripheral edge 35 of the arcuate ferrite magnet molded body 30 so that the peripheral surface 52 contacts the entire part of the end edge 35 when contacting the central portion. The partially elliptical recess 5 of FIGS.
It has a shape having 4. This partial elliptical recess 54
Is set so that uniform chamfering can be performed when the outer dimensions of the bow-shaped ferrite magnet molded body 30 have a predetermined design value. In addition, each rotation center shaft 51 of the rotary grindstones 50A and 50B
Has a fixed supporting position (for example, the moving table 41A,
41B is supported by a bearing of a fixed height fixed on the floor on which 41B is installed), and these rotation center shafts 51 are rotationally driven by a drive source such as a motor (not shown).

As shown in FIGS. 1 and 4, a rotary brush 60 for preventing clogging is rotatably supported by a rotation center shaft 65 adjacent to the rotary grindstones 50A and 50B.
These clogging preventing rotary brushes 60 are steel brushes or the like, have a shape corresponding to the partial elliptical concave portions 54 of the rotary grindstones 50A and 50B, and have the rotary grindstones 50A and 50B.
Is disposed so as to be able to come into contact with a portion to be substantially polished, and has a function of removing cutting powder that has entered the eyes of the abrasive grains of the rotary grindstone. The rotating brush 60 for preventing clogging may be in contact with the rotating grindstones 50A and 50B at all times, or may be brought into contact with the rotating grindstones 50A and 50B regularly or only when necessary. Then it is designed to rotate.

The apparatus shown in FIG. 3 includes a belt conveyor 4
A fixed stopper 61 is fixedly arranged at an intermediate position on 0, and a pusher 62 is fixedly arranged in order to align the position in the width direction on the belt conveyor 40 of the arcuate ferrite magnet molded body 30 stopped here. That is, these fixed stopper 61 and pusher 62 are fixedly supported on the floor surface on which the belt conveyor 40 is installed, for example.

Next, the overall operation of the first embodiment of the present invention will be described with reference to FIG.

A bow-shaped ferrite magnet molding 30 transferred as indicated by an arrow A by traveling of the belt conveyor 40.
Is in a stopped state by hitting the fixed stopper 61, the end surface 34 is further pushed by the pusher 62, and the position in the width direction of the belt conveyor 40 is changed to the correct position B for shifting.
Are aligned with. Thereafter, the outer peripheral surface 32 of the arcuate ferrite magnet molded body 30 at the position B is moved by a suction transfer means (not shown).
Is held by suction, and the molded body 30 for the bow-shaped ferrite magnet is mounted on the molded body mounting table 43A located at the solid line position D of the moving table 41A.
To place. Since the bow-shaped ferrite magnet molded body 30 is not fired and no distortion is generated by firing, the arcuate surface 44 of the upper surface of the molded body mounting table 43A is the inner peripheral surface of the bow-shaped ferrite magnet molded body 30 as shown in FIG. The arc surface 44 can be formed so as to contact almost the entire area of 33.

The bow-shaped ferrite magnet molded body 30 placed on the molded body mounting table 43A at the solid line position D is placed on the molded body mounting table 43A by the first chuck 46 and the second chuck 47 as shown in FIG. While being held and fixed, by moving the molded body mounting table 43A in the Y direction, the bowed ferrite magnet molded body 30 advances in a direction approaching the rotary grindstone 50A as indicated by an imaginary line E, as shown in FIGS. 5 and 6. As described above, the chamfering processing by the rotary grindstone 50A is performed. At this time, while the concave peripheral surface 52 of the rotary grindstone 50A and all the one end edges 35 on the outer peripheral side of the arcuate ferrite magnet molded body 30 are uniformly contacted at an angle of approximately 45 °, the rotary grindstone 50A is indicated by an arrow. By rotating like F, the edge 35 is uniformly polished at once, and the chamfered portion 70 is provided between the outer peripheral surface 32 and the end surface 34 as shown in FIG. In this chamfering method before firing, as shown in FIG. 1 and FIGS. 4 to 6, in the chamfered portion 70 of the arc-shaped ferrite magnet molded body 30 after processing, the rotary grindstone 50A is arranged in the vertical direction (of the outer peripheral surface 32). Since the polishing is performed by rotating it (along the length direction), a vertical streak 71 is formed in the chamfered portion as shown in FIG. 7 (actually finer than that shown in the drawing). It is a line.).

The arcuate ferrite magnet molded body 30 whose one outer peripheral edge 35 has been chamfered retreats to a position slightly away from the rotary grindstone 50A as indicated by an imaginary line G in FIG.
A state in which the direction of 180 ° is converted to a position on the molded body mounting table 43B indicated by an imaginary line H on the moving table 41B by a suction transfer and direction changing means (not shown) (the outer peripheral edge 35 on the non-chamfered side rotates). It is transferred in a state in which it faces the grindstone 50B). The holding and fixing of the bow-shaped ferrite magnet molded body 30 by the molded body mounting table 43B is performed in the same manner as in the molded body mounting table 43A. After that, by moving the molded body mounting table 43B in the Y direction, the molded body 30 for an arc-shaped ferrite magnet advances in a direction approaching the rotary grindstone 50B as indicated by an imaginary line J, and as shown in FIGS. Chamfered. The chamfering process itself is the same as the chamfering process with the rotating grindstone 50A, but since the direction of the arcuate ferrite magnet molded body 30 is changed by 180 °, the chamfering is performed on the outer peripheral edge 35 which is not chamfered by the rotating grindstone 50A. The part 70 will be formed similarly.

The bow-shaped ferrite magnet molded body 30 on which the chamfering of both outer peripheral edges 35 has been completed is used as the moving table 4
1B is returned to the solid line position K by the backward movement (backward movement) of the molded body mounting table 43B included in 1B, and is again transferred to the belt conveyor 40 in the original posture by the suction transfer and direction changing means (not shown). .

The moving tables 41A and 41B are
Main body 42A fixed to the floor where the conveyor 40 is installed,
42B has a drive mechanism such as an air cylinder for reciprocating the molded body mounting bases 43A and 43B in the Y direction,
Further, the rotary grindstone 50A of the molded body mounting table 43A, 43B,
It has a built-in stopper that defines the forward position with respect to 50B. Therefore, it is possible to always form the chamfered portion 70 having a constant shape.

When the shape of the arcuate ferrite magnet molded body 30 is changed, it may be replaced with a molded body mounting table 43A, 43B having an arc surface 44 adapted to the shape.

According to the first embodiment, the following effects can be obtained.

(1) A uniform chamfering of excellent quality can be performed on the bow-shaped ferrite magnet molded body 30 before firing by an apparatus using the rotary grindstones 50A and 50B. By chamfering the molded body before firing, in the conventional chamfering after firing, it was easy to cause chipping at the sharp corners during handling from the molding to the firing process by the device or by a person, but this can be prevented. . As a result, it is possible to reduce the occurrence rate of chipping as compared with chamfering after firing. Also,
The rotational speeds of the rotary grindstones 50A and 50B in the case of surface mounting before firing are much lower than the rotational speed of the grindstone in the case of conventional surface mounting after firing, no cutting fluid is required, and processing is easy. Can be said.

(2) The chamfering at the time of molding with the conventional mold is
Although a crack may be generated in the molded body from the mating portion of the mold during molding, which may lower the yield, this can be prevented. As a result, it is possible to reduce the occurrence rate of chipping as compared with surface mounting using a mold.

(3) Since chamfering can be performed before firing, continuous processing of the outer peripheral surface or the like can be efficiently performed on the arc-shaped ferrite magnet after firing without causing chipping. For example, finish grinding of the outer peripheral surface can be continuously performed with the end surfaces of a large number of arcuate ferrite magnets in contact with each other.

(4) Since the rotary brush 60 for preventing clogging is provided, it is possible to prevent clogging of the rotary grindstones 50A and 50B and prolong the service life.

(5) Since the molded body mounting bases 43A and 43B have the arcuate surface 44 contacting almost the entire inner peripheral surface of the molded body 30, cracks do not occur when the molded body 30 is fixed and held, so that the molded body 30 can be securely held. Can be held at

(6) When the arcuate ferrite magnet molded body 30 is chamfered before firing, a number of vertical streaks are formed in the chamfered portion. The chamfered portion 70 has the same gloss as the other inner and outer peripheral surfaces. If the processing is performed after firing the conventional arc-shaped ferrite magnet, the gloss of the chamfered portion is obviously different.

8 and 9 show a second embodiment of the present invention. In this case, the vacuum suction type molded body mounting base 83 is fixed on the moving table 81. This vacuum suction type molded body mounting table 83 has an arc surface 84 that can come into contact with almost the entire inner peripheral surface 33 of the molded body 30 for an arcuate ferrite magnet, and one (rear side) of the arcuate surface 84 of the molded body 30 for an arcuate ferrite magnet. The end face 34 has a stopper 85 with which the end face 34 abuts.
A large number of suction holes (not shown) connected to a vacuum suction source for vacuum-sucking the arcuate ferrite magnet molded body 30 are formed therein. The moving table 81 is screwed onto a ball screw shaft 87 which is rotationally driven by a servo motor 86, and the rotation of the ball screw shaft 87 causes the rotary grindstone 50 to be driven back and forth on a base 88. There is.

It should be noted that the rotary brush 60 for preventing clogging is provided on the rotary grindstone 50 so as to be in contact therewith, as in the case of the first embodiment described above with reference to FIGS. The chamfered portion can be formed on the outer peripheral edge 35 of the body 30 in the same manner.

FIG. 10 shows a third embodiment of the present invention. In this case, a chamfering rotary brush 90 is used instead of the rotary grindstones 50A and 50B in the first embodiment or the rotary grindstone 50 in the second embodiment. The chamfering rotary brush 90 rotates around a rotation center shaft 95 as a rotation center, and a large number of bristles 91 are integrated with the rotation center shaft 95 so as to be substantially perpendicular to the outer peripheral surface 32 of the arcuate ferrite magnet molded body 30. The bristles 91 have the same virtual outer peripheral curved surface 92 as the peripheral surface 52 of the rotary grindstones 50A and 50B described above.

In the third embodiment, the bow-shaped ferrite magnet molded body 30 is held and fixed by the molded body mounting bases 43A and 43B or the vacuum suction type molded body mounting base 83 of the first or second embodiment. On the other hand, rotary whetstone 50, 50A, 50
Chamfering similar to B can be performed.

According to the third embodiment, the chamfering rotary brush 90 is used to surface-mount the molded body 30 for the arcuate ferrite magnet before firing, thereby achieving the same effect as that of the first or second embodiment. Obtainable. Further, since the chamfering rotary brush 90 does not have a problem of clogging, there is an advantage that the clogging preventing rotary brush 60 used in the first or second embodiment can be omitted.

11 and 12 show a fourth embodiment of the present invention. In this case, a rotary grindstone 100 for chamfering the inner peripheral edge 105 and the bottom edge 106 of the bow-shaped ferrite magnet molded body 30 is shown. The arcuate surface of the molded body mounting table 43A, 43B or the vacuum adsorption type molded body mounting table 83 of the first or second embodiment is formed into an arcuate ferrite magnet molded body 30.
The inner peripheral surface 33 of the arcuate ferrite magnet molded body 30 is fixedly supported with the inner peripheral surface 33 facing upward, and chamfering processing is performed by the rotary grindstone 100. The chamfer 110 can be formed at one time on the edge 105 and the bottom edge 106. However, the rotary grindstone 100 is a generally cylindrical shaped grindstone in which the entire circumferential surface on which the rotation center axis 101 is axially supported is a grindstone in the direction orthogonal to the axial direction of the bow-shaped ferrite magnet molded body 30, and the circle is The columnar peripheral surface 102 is at least an arcuate ferrite magnet molding 30
The shape is in contact with the entire area requiring chamfering. In this case, both ends of the peripheral surface 102 on the grindstone 100 side are shown in FIG.
As shown in FIG. 5, when the arcuate ferrite magnet molded body 30 is in contact with the bottom end edge 106 at an angle θ (approximately 45 °) with respect to the axial end surface 34, the peripheral surface 102 is An axial cross section of the rotary grindstone 100 has a partial elliptical convex portion 103 corresponding to the inner peripheral edge 105 of the arcuate ferrite magnet molded body 30 so as to be in contact with all portions of the bottom edge 105, 106. It has a shape. This partially elliptical convex portion 103 is formed by the arcuate ferrite magnet molding 3
It is set so that uniform chamfering can be performed when the outer dimension of 0 is a predetermined design value.

In the fourth embodiment, by changing the shapes of the molded body mounting table and the rotary grindstone for fixedly supporting the molded body 30 for the bow-shaped ferrite magnet, the molded body 3 for the bow-shaped ferrite magnet is changed.
It is shown that chamfering of the inner peripheral side edge of 0 can be performed in the same manner as in the first or second embodiment.

In each of the above embodiments, the case where the polishing surfaces of the rotary grindstones 50, 50A, 50B and 100 form approximately 45 ° with respect to the axial end surface 34 of the arcuate ferrite magnet molded body 30 has been illustrated. , 45 °, but not limited to 30 °
The acute angle may be in the range of 60 °. That is, when the chamfered portion makes an angle of 30 to 60 ° with respect to the end surface 34 of the molded body, it is useful for prevention of chipping of the edge and improvement of workability in assembling into a case or the like. If the angle is out of the range of 30 to 60 °, the effect of preventing chipping and the effect of improving workability are weakened, and the original meaning of chamfering is lost.

Further, in each of the above embodiments, the rotary fulcrum of the rotary grindstone is fixed, and the molded body mounting table on which the molded body 30 for the bow-shaped ferrite magnet is mounted and fixed is set to move. Is fixed, and the rotation fulcrum of the rotary grindstone can be moved. Furthermore, the rotation direction of the rotary whetstone is
As long as the molded body 30 for the bow-shaped ferrite magnet can be securely fixed to the molded body mounting table, the direction may be opposite to the arrow in FIGS. 1, 8 and 12.

[0054]

As described above, according to the present invention,
In the case of chamfering a bow-shaped ferrite magnet formed by firing a bow-shaped ferrite magnet molded body, at the stage of the bow-shaped ferrite magnet molded body before firing, at the outer or inner edge of the bow-shaped ferrite magnet molded body Since the chamfered part is formed by a rotating grindstone or a rotating brush, conventional chamfering after firing requires a device or a person to perform the finishing grinding process between the molding process and the firing process, and the inner and outer peripheral surfaces of the bow-shaped ferrite magnet after firing. Although it was easy for chipping to occur in sharp corners during handling, this can be prevented and the occurrence rate of chipping can be reduced. Further, continuous machining such as finish grinding can be efficiently performed without causing chipping.

Chamfering at the time of molding with a conventional mold is
Although cracks may have occurred in the molded body from the mating portion of the mold during molding, leading to a decrease in yield, this can be prevented and the occurrence rate of chipping can be reduced.

[Brief description of drawings]

FIG. 1 is a side view showing a main configuration of a first embodiment of a chamfering method and apparatus for an arcuate ferrite magnet according to the present invention.

FIG. 2 is a front cross-sectional view showing the configuration of a main part of the first embodiment.

FIG. 3 is a plan view showing the overall configuration of the first embodiment.

FIG. 4 is a plan view showing a rotary grindstone and a rotary brush for preventing clogging of the first embodiment.

FIG. 5 is a perspective view showing a chamfering step of the arcuate ferrite magnet molded body according to the first embodiment.

FIG. 6 is a side view of the same.

FIG. 7 is a perspective view showing a state in which a chamfered portion is formed on one outer peripheral edge of the arcuate ferrite magnet molded body in the first embodiment.

FIG. 8 is a side view showing the configuration of the main part of the second embodiment of the present invention.

FIG. 9 is a front view showing the main configuration of the second embodiment.

FIG. 10 is a front view showing a configuration of a main part of a third embodiment of the present invention.

FIG. 11 is a perspective view showing a main configuration of a fourth embodiment of the present invention.

FIG. 12 is a side view of the same.

FIG. 13 is a perspective view showing an example of an arcuate ferrite magnet before chamfering.

FIG. 14 is a perspective view showing an example of an arcuate ferrite magnet after chamfering one outer peripheral edge.

FIG. 15 is a plan view showing an apparatus for chamfering a conventional arcuate ferrite magnet after firing.

FIG. 16 is a side sectional view showing a fixing jig of the conventional device and a mechanism around the fixing jig.

FIG. 17 is a front view of a fixing jig portion of the conventional device.

FIG. 18 is a vertical cross-sectional view showing a die structure in the case where surface mounting is performed during molding of a bow-shaped ferrite magnet molded body.

[Explanation of symbols]

 30 Molded body for bow-shaped ferrite magnet 32 Outer peripheral surface 33 Inner peripheral surface 34 End surface 35 Edge 40 Belt conveyor 41A, 41B, 81 Moving table 42A, 42B Main body 43A, 43B, 83 Molded body mounting table 44 Arc surface 45, 85 Stopper 46, 47 Chuck 50, 50A, 50B, 100 Rotating grindstone 51 Rotation center axis 60 Rotation brush for clogging prevention 70 Chamfer 90 Rotation brush for chamfer 91 Bristles

Claims (5)

[Claims] 1. A method for chamfering an arc-shaped ferrite magnet obtained by firing an arc-shaped ferrite magnet molded body, wherein at the stage of the bow-shaped ferrite magnet molded body before firing, the outer or inner circumference of the bow-shaped ferrite magnet molded body. A chamfering method for an arc-shaped ferrite magnet, characterized in that a chamfered portion is formed on the edge of the blade by a rotating grindstone or a rotating brush. 2. The chamfering method for an arcuate ferrite magnet according to claim 1, wherein the chamfered portion is formed by polishing along the lengthwise direction of the outer peripheral surface or the inner peripheral surface of the molded article for the arcuate ferrite magnet. 3. A mounting table on which a molded body for a bow-shaped ferrite magnet before firing is mounted, a fixing means for fixing the molded body for a bow-shaped ferrite magnet on the mounting table, and an outer periphery of the molded body for a bow-shaped ferrite magnet. Alternatively, a cylindrical rotary grindstone capable of contacting at least the entire area of the inner peripheral edge that requires chamfering and rotating around a rotation center axis perpendicular to the axial direction of the arcuate ferrite magnet molded body. Or, a rotating brush, and a moving means for changing the relative positional relationship between the rotating grindstone or the rotating brush and the mounting table, of the rotating grindstone or the rotating brush with respect to the axial end surface of the arcuate ferrite magnet molded body A chamfering device for an arc-shaped ferrite magnet, characterized in that the polishing surface is brought into contact with an acute angle of 30 to 60 ° to polish the edge of the outer circumference or the inner circumference. 4. The arc-shaped ferrite magnet according to claim 3, wherein a rotating brush for preventing clogging is provided at a position where it can come into contact with the rotating grindstone, the rotating brush being provided for removing cutting powder that has entered the eyes of the abrasive grains of the rotating grindstone. Chamfering device. 5. The bow-shaped ferrite magnet according to claim 3, wherein the mounting table has an arcuate surface capable of contacting substantially the entire inner peripheral surface or the outer peripheral surface of the bow-shaped ferrite magnet molded body. Chamfering device.