JPS6140843B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a starter nut loosening prevention device, and more particularly to a starter nut loosening prevention device that is attached to the crankshaft of an engine located at the end of a go-kart body.

FIG. 1 shows a conventional starter nut loosening prevention device. In the conventional starter nut loosening prevention device, a clutch weight carrier 14 is inserted into a tapered portion 12 of a crankshaft 10, and then an outer periphery is formed on a threaded portion 16 of the crankshaft 10 in a shape that can be engaged with a starter motor (not shown). Screw the starter nut 18. This starter nut 1
A center screw 20 is screwed into the screw hole 8, and its tip presses the end of the crankshaft to prevent the starter nut 18 from loosening.
That is, by pressing the end face of the crankshaft 10 with the center screw 20, the screw friction resistance of the starter nut 18 is increased. However, this screw friction resistance is an initial resistance during tightening, and when a loosening torque is applied to the starter nut 18 from the starter motor, depending on the driving direction, the starter nut 18 may move against the threaded portion of the crankshaft 10. There were cases where it loosened from 16. The return torque acting on the starter nut 18 is generated when the starter nut 18 is disengaged from the starting motor or when the engine suddenly accelerates.

The present invention has been made in order to eliminate the drawbacks of the conventional starter nut loosening prevention devices, and it is an object of the present invention to provide a loosening prevention device that does not loosen the starter nut even when a return torque from the starting motor acts on the starter nut. purpose. The present invention provides a threaded portion formed at the end of a crankshaft, a cylindrical starter nut whose outer periphery is formed in a shape that can be engaged with a starter motor, and which is screwed to the threaded portion, and an end surface of the starter nut. A stop nut located inside the formed cylindrical part and screwed to the end of the crankshaft from the same direction as the starter nut, and a center screw that abuts the end of the crankshaft and is screwed inside the stop nut. It is characterized by having. In the present invention, a stop nut that cooperates with the starter nut is used at the end of the crankshaft, and a center screw is screwed into the threaded hole of the stop nut to press the end of the crankshaft, thereby moving the stop nut toward the center screw. It is tightened to prevent it from loosening. Therefore, even if a return torque from the starting motor acts on the starter nut, the stop nut is pressed toward the center screw, so that the stop nut does not loosen. Therefore, the function of preventing loosening of the starter nut is achieved.

Preferred embodiments of the starter nut loosening prevention device according to the present invention will be described in detail below with reference to the accompanying drawings. In FIG. 2, a clutch weight carrier 14 is fixed to the tapered portion 12 of the crankshaft 10 via a key 22. As shown in FIG. A clutch weight shoe 26 is attached to the clutch weight carrier 14 via a pin 24, and the clutch weight shoe 26 can come into contact with a clutch housing 28 disposed around the clutch weight shoe 26. When the clutch weight shoe 26 comes into contact with the inner circumference of the clutch housing 28, the rotational force from the crankshaft 10 is applied to the clutch housing 28.
The rotation of the clutch housing 28 is transmitted to the drive wheels of a go-kart (not shown) via a sprocket 30.

On the other hand, a threaded portion 16 is formed at the end of the crankshaft 10, and an end of a cylindrical starter nut 32 and a stop nut 38 are screwed together. Also,
The outer periphery of the end portion 26 of the starter nut 32 is configured to be movable in engagement with a starter motor (not shown).

A stop nut 38 is arranged inside the starter nut 32, and this stop nut 38 is screwed to the threaded portion 16 of the crankshaft 10 in the same manner as the starter nut 32. Furthermore, a center screw 20 is screwed into the inside of this stop nut 38, and the center screw 20 is tightened until it presses against the end surface of the threaded portion 16 of the crankshaft 10.

Incidentally, members indicated by reference numerals 40 and 42 are bearings and oil seals disposed between the clutch housing 28 and the outer periphery of the starter nut 32.

The operation of the embodiment of the present invention constructed as described above will be explained with reference to FIG.

In FIG. 3, when the center screw 20 is screwed into the inside of the stop nut 38 and the center screw 20 is screwed in even more strongly after contacting the end surface of the threaded portion 16 of the crankshaft 10, the stop nut 38 and the center screw 20 are screwed together. At the threaded joint with the threaded lead part, the state is the same as if the wedges of the threaded lead parts were driven into each other, and the stop nut 38 is strongly drawn toward the center screw 20 and fixed. Therefore, even if a return torque is applied to the starter nut 32 when the starter nut 32 is disengaged from the starting motor or when the engine is rapidly accelerated, the stop nut 38 will be pushed in the axial direction.
Since the screw friction resistance is increased, the stop nut 38 will not loosen. Therefore, starter nut 3
Even if the return torque from the starter motor acts on the starter nut 32, it is blocked by the stop nut 38, so the starter nut 32 will not loosen due to the return torque.

As explained above, according to the starter nut loosening prevention device according to the present invention, there is a cylindrical starter nut that is screwed to the end of the crankshaft, and a cylindrical starter nut that is located inside the starter nut and is attached to the crankshaft from the same direction as the starter nut. Since it has a stop nut that is screwed to the end and a center screw that is screwed inside the stop nut and presses the end of the crankshaft, the stop nut will not loosen even if a return torque is applied to the starter nut. Therefore, loosening of the starter nut can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a conventional starter nut loosening prevention device, FIG. 2 is a sectional view showing the structure of an embodiment of the starter nut loosening prevention device according to the present invention, and FIG. FIG. 3 is a cross-sectional view for explaining the operation of the embodiment according to the present invention. 10... Crankshaft, 16... Threaded portion at the end of the crankshaft, 20... Center screw, 32...
...Start nut, 38...Stop nut.

Claims (1)

[Claims] 1 A threaded portion formed at the end of the crankshaft, a cylindrical starter nut whose outer periphery is formed in a shape that can be engaged with a starter motor and is screwed to the threaded portion at the end of the crankshaft, and a starter nut. Preventing loosening of a starter nut characterized by having a stop nut screwed to the end of the crankshaft from the same direction, and a center screw abutting the end face of the crankshaft and screwed inside the stop nut. Device.