JP3041673U - Flywheel magnet rotor for internal combustion engine - Google Patents

Abstract

(57) [PROBLEMS] To obtain a flywheel magnet rotor for an internal combustion engine, which can prevent rotation between the recoil cup and the flywheel without any trouble even if mold deviation occurs during casting. SOLUTION: A recoil cup 4 that is fastened to a crankshaft of an internal combustion engine together with a flywheel 3 is provided. On the outer surface of the bottom portion 4b of the recoil cup 4, a plurality of rotational force transmission projections 19 are provided so as to project at different positions in the circumferential direction. On the outer surface of the bottom portion 3b of the flywheel 3, rotational force receiving portions 20 that receive the rotational force of the recoil cup 4 via the rotational force transmission projections 19 are provided in a radial direction.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a flywheel magnet rotor for an internal combustion engine, which is provided with a recoil cup that is fixed to the outer surface of the bottom of a boss portion of the flywheel.

[0002]

[Prior art]

 5 and 6 show the structure of a conventional flywheel magnet rotor for an internal combustion engine of this type.

The flywheel magnet rotor 1 for an internal combustion engine includes a flywheel 3 fixed to a crankshaft 2 of the internal combustion engine and a recoil cup 4, and a permanent magnet 5 attached to the outer periphery of the flywheel 3. It is mainly composed of. The flywheel 3 has a tubular portion 3a and a bottom portion 3b that closes one end of the tubular portion 3a in the axial direction. Blower blades 6 are provided at predetermined positions in the circumferential direction at predetermined intervals in a direction away from the bottom portion 3b, and a boss portion 3c provided at the center of the bottom portion 3b is provided with a tapered through hole 3d at the center thereof, and the crankshaft 2 Is passed through and is fastened to the crankshaft 2 with a nut 7. A key groove 3e is provided in the tapered through hole 3d, and a key (not shown) on the crank shaft 2 side is fitted into the key groove 3e so that the boss portion 3c is prevented from rotating on the crank shaft 2. The recoil cup 4 has a tubular portion 4a for winding a starting rope and a bottom portion 4b closing one end in the axial direction of the tubular portion 4a, and a collar at the other end in the axial direction of the tubular portion 4a. The portion 4c is provided with a rope hooking concave portion 4d for locking the knot of the starting rope, and the crankshaft 2 of the internal combustion engine is passed through the hole 4e at the center of the bottom portion 4b. It is fastened with the nut 7. In this case, an anti-rotation protrusion 8 is provided on the outer surface of the bottom of the boss portion 3c, an anti-rotation hole 9 is provided in the bottom portion 4a of the recoil cup 4, and the anti-rotation protrusion 8 is fitted into the anti-rotation hole 9. The recoil cup 4 and the flywheel 3 are connected so as not to rotate.

The crankshaft 2 of the internal combustion engine is rotatably supported on the crankcase 10 by bearings 11. Further, the flywheel 3 is attached to a portion of the crankshaft 2 protruding outside the crankcase 10. On the outer surface of the crankcase 10, a generator 15 is attached by a bracket 15 so that the iron core 13 of the magneto coil 12 faces the permanent magnet 5 on the outer periphery of the flywheel 3 with a gap. Further, a safety cover 16 for covering the flywheel 3 and the electronic generator 14 is provided and attached to the crankcase 10 with screws 17. The safety cover 16 has an inner diameter larger than the outer diameter of the flywheel 3, is provided with a ventilation hole 18 in the middle portion, and the base portion is attached to the crankcase 10 with the screw 17 described above. 16a and an annular lid portion 16c which is connected by a screw 16b so as to close the tip of the tubular portion 16a and exposes the other end side of the recoil cup 4 to the outside from the central hole 16d. ing.

In such a flywheel magnet rotor for an internal combustion engine, on the outer circumference of the tubular portion 4a of the recoil cup 4 which projects outward from the safety cover 16, the collar portion 4c at the end of the tubular portion 4a is provided. A rope for starting (not shown) having a knot locked is wound around the rope hooking concave portion 4d, and the recoil cup 4 is rotated by pulling the rope for starting in this state. The internal combustion engine is started by rotating the crankshaft 2 via the flywheel 3 which is prevented from rotating.

In the flywheel magnet rotor for an internal combustion engine as described above, when the flywheel 3 is cast, the casting die is a die on the side of the tubular portion 4a with the outer surface of the bottom portion 4a of the recoil cup 4 as a boundary. The mold is divided into the mold on the side of the blower blade 6 and casting is performed by matching the molds, but the mold shift occurs when the molds are matched.

This mold deviation is corrected at the time of cutting. This correction is performed with reference to the cylindrical portion 4a which is the peripheral wall of the flywheel 3 in consideration of the imbalance of the flywheel 3. For example, the tube portion 4a of the flywheel 3 is attached to the processing machine, the mold deviation of the blower blade 6 side is corrected, the outer peripheral portion of the next blower blade 6 side is attached to the processing machine, and the boss portion 3c is tapered. The machining of the cylindrical through hole 3d and the machining of the inner peripheral surface and the outer peripheral surface of the cylindrical portion 4a are performed in the same process, and the inner and outer surfaces of the cylindrical portion 4a are aligned with the taper through hole 3d. It is performed with high precision.

[0008]

[Problems to be solved by the device]

 Therefore, a dimensional error occurs in the space between the whirl-stop projection 8 on the side surface of the blower blade 6 and the center of the tapered through hole 3d by the amount of the mold deviation during casting, and the whirl-stop projection 8 is used for recoil. There is a problem that the cup 4 cannot be fitted into the rotation stop hole 9.

An object of the present invention is to provide a flywheel magnet rotor for an internal combustion engine, which can prevent the rotation between the recoil cup and the flywheel from being disturbed even if the mold shift occurs during casting.

Another object of the present invention is to provide a flywheel magnet rotor for an internal combustion engine, which can prevent rotation between the recoil cup and the flywheel in both forward and reverse directions.

Another object of the present invention is to obtain a flywheel magnet rotor for an internal combustion engine, which is capable of mounting the recoil cup without trouble even if a rotational force receiving portion is provided on the outer surface of the bottom of the flywheel. .

[0012]

[Means for Solving the Problems]

 A flywheel magnet rotor for an internal combustion engine, which is to be improved by the present invention, has a tubular portion and a bottom portion closing one end in the axial direction of the tubular portion, and a permanent magnet is attached to the inner circumference of the tubular portion. A flywheel having a through hole through which the crankshaft of an internal combustion engine is inserted in the center boss part of the bottom part, and a recoil cup that is fixed to the outer surface of the bottom part of the boss part and fixed to the crankshaft together with the flywheel. It is a structure with and.

According to the present invention, a plurality of rotational force transmitting protrusions are provided on the outer surface of the bottom of the recoil cup at different positions in the circumferential direction. On the outer surface of the bottom of the flywheel, rotational force receiving portions that receive the rotational force of the recoil cup via the rotational force transmission protrusions are provided so as to protrude in the radial direction.

According to this structure, the rotational force transmission protrusion on the outer surface of the bottom of the recoil cup rotates at any position within the radial length of the rotational force receiving portion of the flywheel. It will be stopped and locked. Therefore, even if the mold is misaligned during the casting of the flywheel, the rotation stop between the recoil cup and the flywheel can be prevented without any trouble.

In this case, on the outer surface of the bottom of the flywheel, an auxiliary protrusion can be provided in a radial direction at a position where at least one rotational force transmitting protrusion of the recoil cup is sandwiched with the rotational force receiving portion. With this configuration, the rotation force transmitting projection of the recoil cup is sandwiched between the rotation force receiving portion and the auxiliary projection, so that the rotation stop between the recoil cup and the flywheel can be performed in both forward and reverse directions.

Further, it is preferable that the rotational force receiving portion is provided so as to project at the same height as the boss portion. With this arrangement, even if the rotational force receiving portion exists on the outer surface of the bottom of the flywheel, the recoil cup can be attached to the outer surface of the bottom of the boss without any trouble.

[0017]

[Embodiment of the invention]

 1 (A), 1 (B) to 3 show a first example of an embodiment of a flywheel magnet rotor for an internal combustion engine according to the present invention, and FIG. 1 (A) is used in this example. 1B is a plan view of the recoil cup, FIG. 1B is a cross-sectional view taken along line XX of FIG. 1A, and FIG. 2 is a rotation force transmission protrusion of the recoil cup and the rotation of the flywheel, which are essential parts of this example. FIG. 3 is a plan view showing the relationship with the force receiving portion, and FIG. 3 is a vertical cross-sectional view showing the engagement relationship between the rotational force transmitting projection of the recoil cup and the rotational force receiving portion of the flywheel, which is the main part of this embodiment. . The parts corresponding to those in FIGS. 5 and 6 described above are designated by the same reference numerals.

In this flywheel magnet rotor for an internal combustion engine, a plurality of (two in this example) rotational force transmission projections 19 are provided on the outer surface of the bottom portion 4b of the recoil cup 4 at different positions in the circumferential direction. It is protruded by cutting and raising from the bottom portion 4b. Further, on the outer surface of the bottom portion 3b of the flywheel 3, two rotational force receiving portions 20 for receiving the rotational force of the recoil cup 4 via the rotational force transmitting projections 19 are provided so as to project in the radial direction. There is. These rotational force receiving portions 20 are integrally formed with the flywheel 3. As shown in FIG. 3, these rotational force receiving portions 20 are provided so as to protrude from the bottom portion 3b at the same height as the boss portion 3c. The recoil cup 4 is positioned so that the rotational force transmitting projection 19 thereof contacts the rotational force receiving portion 20 of the flywheel 3 when the recoil cup 4 rotates in the direction of the arrow shown in FIG. It is fastened to the crankshaft 2 of. Other configurations are similar to those in FIGS. 5 and 6 described above.

With such a structure, the rotational force transmission projections 19 on the outer surface of the bottom of the recoil cup 4 are not limited as long as they are within the radial length of the rotational force receiving portions 20 of the flywheel 3. Even at the position, the rotation stopper will be locked. Therefore, even if the mold is misaligned during the casting of the flywheel 3, the rotation prevention between the recoil cup 4 and the flywheel 3 can be performed without any trouble. That is, when the recoil cup 4 is rotated by the starting rope in the direction of the arrow as shown in FIG. 2 as described above, the rotational force of the recoil cup 4 is transmitted via the rotational force transmission projections 19. It is transmitted to each rotational force receiving portion 20 of the flywheel 3 and also transmitted to the crankshaft 2 of the internal combustion engine via the flywheel 3. Further, since the rotational force receiving portion 20 is at the same height as the boss portion 3c, even if the rotational force receiving portion 20 is present on the outer surface of the bottom portion of the flywheel 3, the recoil cup 4 can be attached to the outer surface of the bottom portion of the boss portion 3c. Can be installed without any problem.

FIG. 4 shows a second example of an embodiment of the flywheel magnet rotor for an internal combustion engine according to the present invention. The parts corresponding to those in FIG. 2 described above are designated by the same reference numerals.

In this flywheel magnet rotor for an internal combustion engine, an auxiliary protrusion is provided on the outer surface of the bottom portion 3 b of the flywheel 3 so as to sandwich one rotational force transmitting protrusion 19 of the recoil cup 4 together with the rotational force receiving portion 20. 21 is provided to project in the radial direction. Other configurations are the same as those in FIGS. 1 (A) and 1 (B) to FIGS. 3 and 4 and 5 described above.

By thus providing the auxiliary protrusion 21 and sandwiching the rotational force transmitting protrusion 19 of the recoil cup 4 together with the rotational force receiving portion 20, the rotation prevention between the recoil cup 4 and the flywheel 3 is corrected. ， Can be done in opposite directions.

The auxiliary protrusion 21 may be provided for each rotational force receiving portion 20. Further, the rotational force transmitting projection 19 of the recoil cup 4 can be integrally formed when the recoil cup 4 is formed by molding such as casting.

[0024]

[Effect of the invention]

 In the present invention, a plurality of rotating force transmitting projections are provided on the outer surface of the bottom of the recoil cup at different positions in the circumferential direction, and the rotational force of the recoil cup is projected on the outer surface of the bottom of the flywheel. Since the rotational force receiving portions that are received via the projections are arranged in the radial direction, the rotational force transmitting projections of the recoil cup must be within the radial length range of the rotational force receiving portion of the flywheel. However, the detent is locked at any position. Therefore, even if the mold is misaligned during the casting of the flywheel, the detent between the recoil cup and the flywheel can be prevented without any trouble.

[Brief description of the drawings]

FIG. 1A is a plan view of a recoil cup used in the first example of the embodiment of the flywheel magnet rotor for an internal combustion engine according to the present invention, and FIG. 1B is XX of FIG. It is a line sectional view.

FIG. 2 is a plan view showing the relationship between the rotational force transmitting protrusion of the recoil cup and the rotational force receiving portion of the flywheel, which is the main part of this example.

FIG. 3 is a vertical cross-sectional view showing an engagement relationship between a rotational force transmitting projection of the recoil cup and a rotational force receiving portion of the flywheel, which is a main part of this example.

FIG. 4 is a plan view showing the relationship between the rotational force transmitting protrusion of the recoil cup and the rotational force receiving portion of the flywheel showing the second example of the embodiment of the flywheel magnet rotor for an internal combustion engine according to the present invention. is there.

FIG. 5 is a longitudinal sectional view showing a state in which a conventional flywheel magnet rotor for an internal combustion engine is attached to a crankshaft of the internal combustion engine.

FIG. 6 is a bottom view of a conventional flywheel magnet rotor for an internal combustion engine.

[Explanation of symbols]

 1 Internal combustion engine flywheel magnet rotor 2 Internal combustion engine crankshaft 3 Flywheel 3a Tube part 3b Bottom part 3c Boss part 3d Tapered through hole 3e Key groove 4 Recoil cup 4a Tube part 4b Bottom part 4c Collar part 4d Rope hooking recess 4e hole 5 permanent magnet 6 blower blade 7 nut 8 rotation stop protrusion 9 rotation stop hole 10 crankcase 11 bearing 12 generator coil 13 iron core 14 generator 15 bracket 16 safety cover 16a cylinder part 16b screw 16c lid part 16d hole 17 screw 18 ventilation Hole 19 Rotational force transmission protrusion 20 Rotational force receiving portion 21 Auxiliary protrusion

Claims (3)

[Utility model registration claims] 1. A cylindrical body and a bottom portion that closes one end of the cylindrical portion in the axial direction, a permanent magnet is attached to an inner circumference of the cylindrical portion, and a boss portion in the center of the bottom portion of an internal combustion engine. For a internal combustion engine including a flywheel provided with a through hole through which a crankshaft is passed, and a recoil cup that is attached to the outer surface of the bottom of the boss to prevent rotation and is fastened to the crankshaft together with the flywheel. In the flywheel magnet rotor, a plurality of rotational force transmitting projections are provided on the bottom outer surface of the recoil cup at different positions in the circumferential direction, and the rotation force of the recoil cup is provided on the bottom outer surface of the flywheel. A flywheel magnet rotor for an internal combustion engine, characterized in that rotational force receiving portions that receive the rotational force transmission protrusions are provided in a radial direction. 2. An auxiliary protrusion is radially provided on an outer surface of a bottom portion of the flywheel at a position where at least one of the rotation force transmitting protrusions of the recoil cup is sandwiched with the rotation force receiving portion. The flywheel magnet rotor for an internal combustion engine according to claim 1. 3. The rotating force receiving portion is projected at the same height as the boss portion.
A flywheel magnet rotor for an internal combustion engine as set forth in.