JP2003088055A - Rotor of magnetogenerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent so-called sag in an internally tapped hole at the bottom wall of a yoke. SOLUTION: In the rotor of a magnetogenerator, the internally tapped hole 31 is opened at the bottom wall 1 of a yoke 20 made roughly in the shape of a cup, and also a burring part 35 is projected at the brim of the opening of the internally tapped hole 31 at one end face of the bottom wall 21 of the yoke 20. A sag preventive groove 36 is cut at a section adjacent to the burring part 35 at one end face of the bottom wall 21 of the yoke 20. Consequently, in press-processing the burring part 35 to the bottom wall 21 of the yoke 21, the sag preventive part 53 forming the sag preventive groove 36 can prevent the drag of material to the burring part 35, so that the rotor can prevent the occurrence of the so-called sag in the internally tapped hole 31 at the bottom wall 21 of the yoke, and can prevent the drop of the mounting accuracy caused by sag in a cooling fan to the bottom wall 21 of the yoke.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor of a magnet generator, and is used, for example, in small vehicles such as motorcycles, outboard motors, portable generators, and the like. The present invention relates to a magnet generator (flywheel magneto) that is effectively used as a rotor. 2. Description of the Related Art In general, a magnet generator used for a small vehicle, an outboard motor, a portable generator, or the like has a plurality of magnets arranged at equal intervals on an inner peripheral surface of a substantially bowl-shaped yoke (flywheel). And a plurality of coil units (constituted by winding a coil around a core) disposed at equal intervals inside a yoke of the rotor. And a stator is provided on the outer periphery of the engine, and the rotor is fitted on the rotating shaft of the engine. In this magnet generator, the rotor is swung around the electron emission by the rotation of the rotating shaft driven by the engine, and relatively moves within the magnetic field of the magnet of the rotor. An electromotive force will be induced in the magnetic pole coil. In this type of conventional magnet generator, a cooling fan is attached to a yoke by the following structure in order to cool the engine. That is, a plurality of female screw holes are formed in a bottom wall of a yoke formed of a substantially bowl shape by press working using a structural steel material by punching after compression (coining), and the yoke of the yoke is formed. A cylindrical bulging portion (burring portion) formed by compression is protruded from an edge of an opening of each female screw hole on one end surface of the bottom wall. On the other hand, the cooling fan is integrally formed by using a resin, and a collar formed of a metal and having a cylindrical shape is insert-molded at a position facing each female screw hole of the yoke in the cooling fan. The cooling fan is fastened by fitting each collar to the end face of the bottom wall of the yoke opposite to the burring portion in alignment with the female screw hole, and the male screw member is inserted through the collar and screwed into the female screw hole. . [0004] Generally, a pilot hole of a female screw hole is formed by press working in consideration of the ease of processing. However, when the plate thickness is about 3 mm, burring may be performed on the female screw hole to secure the strength. However, in this case, the tip of the burring portion may be thin and the screw strength may be insufficient. Also,
In the rotor of the magnet generator, the clearance between the rotor bottom and the stator is small, and there is a fear that the burring portion may interfere with internal components such as the stator, and the height of the burring portion must be strictly controlled. Extra man-hours are generated. In order to improve the above, it is conceivable to form a pilot hole by first performing a drilling process after compression (coining) when processing a female screw hole. After this pilot hole is formed, a rolling tapping process for forming a screw is performed.Before this, in order to prevent the occurrence of burrs on the opening edge at the start of threading, the edge should be chamfered. However, it is possible. However, in a rotor of a magnet generator in which the cooling fan is screwed to the outer end surface of the bottom wall of the yoke via a collar, if the bottom wall of the yoke is subjected to burring or chamfering. A so-called sheer (shea) is formed at the edge of the opening opposite to the burring portion of the female screw hole.
r drop, roll over. Material shrinkage caused by plastic working. ) Is formed,
Since the flatness of the seat surface of the cooling fan in each female screw hole is impaired, there is a problem that the mounting accuracy of the cooling fan is reduced. An object of the present invention is to provide a rotor of a magnet generator capable of minimizing so-called dripping in a female screw hole in a bottom wall of a yoke. A rotor of a magnet generator according to the present invention has a female screw hole formed in a bottom wall of a substantially bowl-shaped yoke and a bottom wall of the yoke. In a rotor of a magnet generator having a burring portion protruding from an opening edge of the female screw hole on one end surface of the yoke, a material slip prevention groove is provided at a portion adjacent to the burring portion on one end surface of the bottom wall of the yoke. Is submerged. According to the above-mentioned means, at the time of burring on one end surface of the bottom wall of the yoke, the sagging prevention groove, which is a material shrinkage, is submerged in a portion adjacent to the burring portion, so that the yoke bottom wall is formed by burring. The occurrence of so-called drooping in the female screw hole of (1) can be prevented. An embodiment of the present invention will be described below with reference to the drawings. In the present embodiment, the rotor of the magnet generator according to the present invention is configured as a rotor (hereinafter referred to as a rotor) of the motorcycle magnet generator shown in FIG. As shown in FIG. 1, the rotor 1 includes a boss member 10 to which a rotating shaft (not shown) is fitted, and a yoke 20 serving also as a flywheel.
And the yoke 20 are serrated. That is, the boss member 10 is made of a structural steel material, and is formed by pressing a flange 1 formed in a circular annular shape on the outer periphery of one end by press working.
1, the boss member 10
A male serration 12 is engraved over the entire circumference and the entire length of the outer peripheral surface of the connecting portion with the flange 11. On the other hand, the yoke 20 is made of a structural steel material and is formed into a substantially round bowl shape by press working.
A boss fixing hole 22 is formed concentrically on the bottom wall 21 of the boss, and a female serration 23 is engraved on the inner peripheral surface of the boss fixing hole 22 over the entire circumference and the entire length. Then, the boss member 10 is inserted into the boss fixing hole 22 of the yoke 20 from the outside of the bottom wall 21 so that the male serration 12 and the female serration 23 are serrated and joined, and the cylindrical outer peripheral portion of the boss member 10 is buckled and crimped. Buckling crimping part 13
Has been concluded by In the hollow portion of the boss member 10, a tapered inner peripheral surface 14 that fits with a tapered outer peripheral surface of a rotating shaft (not shown) is formed so as to increase in diameter in a direction away from the flange 11. I have. A nut (not shown) for screwing a rotating shaft (not shown) on the outer end surface of the flange 11.
Are formed concentrically. On the other hand, after a plurality of magnets 25 press-fit a synthetic resin case 26 containing the magnets 25 into the yoke 20 on the inner peripheral surface of the side wall 24 of the yoke 20.
It is fixed at a predetermined position in the circumferential direction by a swaging portion 27 formed by swaging. A part of the side wall of the yoke 20 is formed with a reluctor portion 28 which bulges outward in the radial direction. At the boundary between the bottom wall 21 of the yoke 20 and the side wall 24, six ventilation holes 29 are arranged at regular intervals in the circumferential direction and are opened in a substantially elliptical shape long in the circumferential direction.
In the six air holes 29, three window holes 30 and three female screw holes 31 are arranged alternately in the circumferential direction on the concentric circle and between the adjacent air holes 29, 29, respectively. Has been established. Next, a female screw hole 3 which is a main feature of the present invention will be described.
1 will be described based on the molding method shown in FIGS. In the method of forming a female screw hole according to the present embodiment, a punch 40 and a die 50 shown in FIG. 2A are used. The punch 40 includes a cylindrical main body 41 having an outer diameter slightly larger than the inner diameter (nominal diameter) of the female screw hole 31, and a chamfer for forming a chamfered portion on the outer peripheral edge at the lower end of the main body 41. The portion forming taper 42 is formed in a tapered shape corresponding to the chamfered portion. A burring portion forming hole 52 for forming a burring portion is formed in a circular hole shape having a predetermined depth in a portion of the upper surface of the main body 51 of the other die 50 facing the punch 40. Outside the burring portion forming hole 52 on the upper surface of the main body 51 of the die 50, a circular ring shape having a fixed height is formed, and a flare-preventing portion 53 is provided concentrically and protruded. The surface and the rising wall surface of the burring portion forming hole 52 are in the same state. The height H and the circumferential width W of the droop preventing portion 53 are appropriately determined according to the amount of material shrinkage (dripping) that occurs when the punch 40 is pushed into the bottom wall 21 of the yoke 20. Will be set. Incidentally, the amount of droop generated when the punch 40 is pushed into the bottom wall 21 of the yoke 20 varies depending on various press working conditions such as the outer diameter of the punch 40, the pushing force, the material of the yoke 20, and the plate thickness. Therefore, the height H and the circumferential width W of the droop preventing portion 53 are determined by experiments and computer simulations and past accumulations corresponding to desired design conditions such as the inner diameter of the female screw hole 31, the material and the plate thickness of the yoke 20, and the like. It is desirable to set appropriately by an empirical method based on data or the like. As shown in FIG. 2B, a portion 32 of the bottom wall 21 of the yoke 20 for forming the female screw hole 31 is provided between the punch 40 and the die 50. Be placed. In this state, as shown in FIG. 2C, the material of the female screw hole forming portion 32 in the bottom wall 21 of the yoke 20 is pushed into the die 50 by the punch 40. By pushing the material, the female screw hole forming portion 33 is formed in the female screw hole forming portion 32 by plastic working. Next, when the punch 40 and the die 50 are opened, as shown in FIG.
The female screw hole forming portion 33 is plastically processed at the female screw hole forming portion 32 on the bottom wall 21 of the zero. That is,
A chamfered portion 34 is formed on the upper surface of the female screw hole forming portion 33 by a punch 4.
The burring portion 35 is formed in the lower surface of the female screw hole forming portion 33 by the burring portion forming hole 52 of the die 50 and is swelled. A drooping prevention groove 36 is concentrically disposed in a circular annular groove shape with a certain height by a drooping prevention portion 53 outside of 35. Thereafter, as shown in FIG. 3A, a pilot hole 37 is formed in the female screw hole forming portion 33 of the bottom wall 21 of the yoke 20 by punching and pressing. Next, as shown in FIG. 3B, a female screw portion 38 of a female screw hole is formed on the inner peripheral surface of the pilot hole 37 by a rolling tapping method. As described above, the female screw hole 31 is formed in the bottom wall 21 of the yoke 20. By the way, when the die 50 'without the sagging prevention portion shown in FIG. 4A is used in the press working of the female screw hole forming portion, it is shown in FIG. 4B. As described above, since the burring portion forming hole 52 of the die 50 pulls the material of the female screw hole forming portion 32 pushed by the chamfered portion forming taper 42 of the punch 40, the female screw hole forming portion 33 ′.
A dripping portion 39 is formed around the chamfered portion 34 in FIG. As shown in FIG. 4 (c), when the droop portion 39 is formed on the periphery of the opening on the cooling fan mounting side of the female screw hole 31 ', the seating surface of the collar 61 of the cooling fan decreases. Accordingly, the fastening strength of the male screw member (not shown) is reduced or the fastening posture is inclined, so that the mounting accuracy of the cooling fan 60 is reduced. In the present embodiment, at the time of pressing the female screw hole forming portion, as shown in FIG. 2A, a die in which a dripping preventing portion 53 is provided outside the burring portion forming hole 52 is provided. Since 50 is used, the chamfer 3
The generation of a drooping portion around the periphery 4 can be suppressed. That is, as shown in FIG. 2C, the chamfered portion 34 is depressed and formed by the chamfered portion forming taper 42 of the punch 40 on the upper surface of the female screw hole forming portion 33, and the burring portion 35 is formed by the female screw hole forming portion 33. When the material of the female screw hole forming portion 32 is guided toward the burring portion 35 when the bulging portion forming hole 52 of the die 50 is formed by bulging the lower surface of the burring portion 52, the drooping portion is formed. And the run-out preventing portion 53 prevents the material from being guided, so that the occurrence of the run-out portion due to the shrinkage of the material around the chamfered portion 34 is prevented. According to the present embodiment, as shown in FIG. 3 (c), the occurrence of drooping at the edge of the female screw hole 31 at the opening end on the cooling fan mounting side is prevented. Since the seating surface of the collar 61 can be prevented from decreasing, a male screw member (not shown) can be used.
Therefore, it is possible to prevent the fastening strength from being reduced or the fastening posture to be inclined, and to prevent the mounting accuracy of the cooling fan 60 from being reduced. Further, in the process of forming the female screw hole forming portion 33, the chamfered portion 34 can be depressed and formed on the upper surface of the female screw hole forming portion 33 by the chamfered portion forming taper 42 of the punch 40. After the pilot hole 37 is opened, it is possible to prevent the occurrence of burrs when tapping the female screw portion 38 into the pilot hole 37 by the rolling tapping method. Further, since a burring portion 35 is protruded from an end of the female screw hole 31 opposite to the chamfered portion 34, a sufficient effective dimension of the female screw portion 38 can be ensured, and the cooling fan can be fastened. In this case, sufficient fastening strength can be secured. It should be noted that the present invention is not limited to the above-described embodiment, but may be modified without departing from the scope of the invention.
It goes without saying that various changes can be made. For example, as shown in FIG. 5, a second droop preventing portion 54 may be provided on the bottom of the burring portion forming hole 52 of the die 50. When the second droop preventing portion 54 is provided in a protruding manner, as shown in FIG.
During coining with the die 50 and the die 50, the second drooping preventing portion 54 prevents the material from being guided into the burring portion forming hole 52, so that dripping can be more reliably prevented. In the above embodiment, the rotor of the magnet generator for a two-wheeled vehicle has been described. However, the present invention relates to a magnet generator used for a small vehicle such as a motorcycle, an outboard motor, and a portable generator. It can be applied to all rotors. As described above, according to the present invention,
The so-called drooping in the female screw hole in the bottom wall of the yoke can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a rotor of a magnet generator according to an embodiment of the present invention, wherein (a) is a plan view and (b) is b in (a).
It is sectional drawing which follows the -b line. FIGS. 2 (a), (b), (c) and (d) are enlarged partial cross-sectional views showing a step of forming a female screw hole forming portion. FIG. 3 is an enlarged partial sectional view showing a step of forming a female screw hole; FIG. 4 is an enlarged partial sectional view showing a comparative example. FIGS. 5A, 5B, 5C, and 5D are enlarged partial cross-sectional views showing a forming process of a female screw hole forming portion according to another embodiment. [Description of Signs] 1 ... Rotor of magnet generator, 10 ... Boss member, 11 ... Flange, 12 ... Male serration, 13 ... Buckling crimping portion, 14 ... Tapered inner peripheral surface, 15 ... Recessed portion, 20 ... Yoke ,
21: bottom wall, 22: boss fixing hole, 23: female serration, 24: side wall, 25: magnet, 26: case, 2
7 ... Crimping part, 28 ... Retractor part, 29 ... Blow hole,
Reference numeral 30: window hole, 31: female screw hole, 32: female screw hole forming portion, 33: female screw hole forming portion, 34: chamfered portion, 35: burring portion, 36: drooping prevention groove, 37: pilot hole, 38: female screw portion, 39: whore part, 40: punch, 41: body, 4
2 ... Chamfer forming taper, 50 ... Die, 51 ... Main body, 5
2 ... burring part forming hole, 53 ... droop prevention part, 54 ... second droop prevention part, 60 ... cooling fan, 61 ... collar, 3
1 ': female screw hole; 33': female screw hole forming portion; 50 ': die.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Yoichi Segawa             1-2681 Hirosawa-cho, Kiryu-shi, Gunma Stock             Inside the company Mitsuba F-term (reference) 5H615 AA01 BB02 BB14 PP02 PP07                       SS03 SS10 SS13 TT04                 5H621 BB07 GA01 HH03 JK01

Claims (1)

Claims 1. In a rotor of a magnet generator in which a screw hole is formed in a bottom wall of a yoke formed in a substantially bowl shape, the rotor is pulled to the outer periphery of the screw hole inside the yoke. A rotor for a magnet generator, wherein a prevention groove is submerged.