JPH0124379Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a small engine that uses a generator to ignite a spark plug using the driving force of a crankshaft.

A conventional small engine of this type is one shown in FIG. In the figure, reference numeral 1 denotes a crankshaft which is rotationally driven by a piston 3 fitted into a cylinder 2. A flywheel boss 4 is fixed to this crankshaft 1 with a nut 5 and a key 6, and a rivet 7 is attached to the outer periphery of the crankshaft. A flywheel 8 is attached. The flywheel 8 is formed into a cylindrical shape with the crankcase 9 side open, and includes a cover 10a integrally formed with the crankcase 9, and a cover 10 detachably attached to the cover 10a.
covered by b.

Further, an ignition voltage generating circuit 13 having an armature winding 12 mounted on a base plate 11 is mounted on the crankcase 9, and a magnet body is mounted on the inner peripheral surface of the flywheel 8 facing the armature winding 12. As the crankshaft 1 rotates, a high voltage is generated in the armature winding 12, which is then energized to the spark plug 15.

In the above engine, when adjusting the ignition timing, since the flywheel 8 is fixed to the crankshaft 1 with the key 6, fine adjustment such as shifting the position of the flywheel 8 in the rotational direction is not possible.
Therefore, remove the cover 10b and flywheel 8, and connect the armature winding 12 on the base plate 11 to the crankshaft 3.
After setting the flywheel 8 and cover 10b to an appropriate position in the direction of rotation, the flywheel 8 and cover 10b are returned to their original positions, the engine 16 is driven, and the ignition timing is checked.The ignition timing is not appropriate. when,
Furthermore, this process had to be repeated, which took a considerable amount of time.

This idea was made in order to eliminate the above-mentioned drawbacks.In addition to installing a magnet on one side of the flywheel and cover and an ignition voltage generation circuit on the other, the installation position of the cover side on the engine body was changed in the circumferential direction. By making it possible to change the ignition timing to
The purpose is to provide a small engine whose ignition timing can be easily adjusted.

An embodiment of this invention will be described below with reference to the drawings. In FIG. 1, a flywheel boss 23 is fixed to a crankshaft 22 protruding outward from a crankcase 21 at the bottom of an engine body 20 with a nut 24 and a key 25, and a flywheel 26 is attached to the outer periphery of the crankshaft 22. It is installed. The flywheel 26 is formed into a cylindrical shape with an open side opposite to the engine main body 20, and a magnet body 27 is attached to the inner circumferential surface of the flywheel 26. 28a is a cover integrally formed with the engine body 20, and the other cover 2
8b and covers the flywheel 26,
This cover 28b is fastened so that it can rotate slightly in the circumferential direction 50 by inserting bolts 29 into long holes 60 provided in the cover 28b and screwing them onto the cover 28a, as shown in FIG. . In other words, the bolt 29 and the elongated hole 60 constitute a variable attachment mechanism. In addition, the cover 28 in FIG.
An ignition voltage generating circuit 31 having an armature winding 30 and the like is mounted on the inner surface of b at a position facing the magnet body 27 of the flywheel 26, and the flywheel 26 is rotated by the drive of the engine 32. ,
A high voltage is generated in the armature winding 30 to ignite the spark plug 33.

Further, as shown in FIG. 3, a through hole 34 is provided in the circumferential portion of the cover 28a, and an indicating portion 36 consisting of a pointer is provided protruding from the inner surface of the cover 28a, facing the through hole 34. The instruction part 3
An indicator part 37 consisting of another scale is provided on the outer peripheral surface of the flywheel 26 opposite to the indicator part 6, and as shown in FIG.
The scales 39, 40 are also on the flange parts 38a, 38b.
are provided respectively, and are used for adjusting the mounting position in the circumferential direction 50 of the cover 28b on which the armature winding 30 is mounted.

In the above configuration, when adjusting the ignition timing, a timing light (not shown) is connected in parallel to the circuit from the armature winding 30 to the spark plug 33 to adjust the ignition timing at each ignition timing. When the timing light is set to turn on and the engine 32 is driven, the indicator 3 in the vicinity of the timing light is inserted through the through hole 34 formed in the cover 28a.
This is done by illuminating 6 and 37. That is, the flywheel 26 is driven by the engine 32.
rotates at high speed, but due to the strobe principle, the positions of the indicating parts 36 and 37 can be visually confirmed with a timing light. At this time, if there is a deviation in the ignition position, the error detected by the indicator parts 36 and 37 is
Flange portions 38a of the covers 28a and 28b,
The scales 39 and 40 provided on the cover 28b are set as standard, and correction is made by loosening the bolts 29 and 29 and slightly rotating the cover 28b in the circumferential direction 50.

In other words, the ignition timing can be easily adjusted by slightly rotating the cover 28b without having to remove the cover or flywheel as in conventional devices.

Further, in the above configuration, the base plate on which the armature winding is mounted can be eliminated, so that cost reduction, weight reduction, and size reduction in the axial direction 41 can be achieved.

Furthermore, the flywheel 26 is connected to the engine body 20.
Since the flywheel 26 can have a shape that is open toward the outside, the center of gravity of the flywheel 26 moves toward the crankcase 21 compared to the conventional device.
The burden on the crankshaft 22 and bearings 42 is reduced.

FIG. 4 shows a second embodiment of this invention, in which an armature winding 30 is attached to a cover 28b via a base plate 43, and by rotating the cover 28b with respect to the cover 28a, the above-mentioned effect can be achieved. Similarly, it is easy to adjust the ignition timing.

FIG. 5 shows a third embodiment of this invention, in which the armature winding 30 is attached to the cover 28b via a base plate 43, and this base plate 43 has elongated holes 62, The ignition timing can be adjusted by loosening the bolts 44, 44 from the outside and rotating the base plate 43 together with the bolts 44. In this embodiment, the bolt 44 and the elongated hole 62 constitute a variable attachment mechanism. In addition, cover 28
By providing a through hole 34 in b, a display section 36 around the hole, and a display section 37 at the end of the flywheel 26, the ignition timing can be checked.

FIG. 7 shows a fourth embodiment of this invention, in which a magnet body 27 is attached to the outer peripheral surface of a flywheel 26, and an armature winding 30 is attached to a cover 28 opposite to the magnet body 27.
Although not shown, the through hole 3 is attached to the inner circumferential surface of the
4 and the indicating portion 36 are provided on the cover 28b, and the indicating portion 37 is provided on the end face of the flywheel 26, respectively, and the same effects as in the first embodiment are achieved.

As explained above, according to this invention, the ignition timing can be adjusted by simply moving the cover or the base plate attached to it in the circumferential direction without removing the cover from the engine body. Since a mechanism is provided that allows the ignition timing deviation to be visually confirmed from the outside, it is possible to provide a small engine in which the ignition timing can be easily adjusted.

[Brief explanation of drawings]

Fig. 1 is a side view showing the first embodiment of this invention, Fig. 2 is a side view showing a cover covering the flywheel of the first embodiment, Fig. 3 is a plan view of Fig. 2,
FIG. 4 is a sectional view showing a second embodiment of this invention;
FIG. 5 is a sectional view showing a third embodiment of this invention;
FIG. 6 is a side view showing a cover covering the flywheel of the third embodiment, FIG. 7 is a sectional view showing the fourth embodiment of this invention, and FIG. 8 is a sectional view showing a conventional example. 20...engine body, 22...crankshaft,
26... Flywheel, 27... Magnet, 28
a, 28b...cover, 30...armature winding, 3
1...Ignition voltage generation circuit, 32...Engine, 3
4...Through hole, 36, 37...Instruction part, 43...Second plate, 29, 60 or 44, 62...Variable attachment mechanism.

Claims (1)

[Claims for Utility Model Registration] A flywheel 26 is fixed to the crankshaft 22, a cover 28b covering the flywheel 26 is fixed to the engine body 20, and the flywheel 26 is fixed to the engine body 20.
6 and the cover 28b, the ignition voltage generating circuit 3 has a magnet body 27 on one side and an armature winding 30 on the other side.
1 and a variable attachment mechanism 29, 60 for attaching the cover 28b to the engine body 20 so that the attachment position in the circumferential direction of the crankshaft 22 can be changed; and a magnet body 27 attached to the cover 28b. Alternatively, the base plate 43 to which the ignition voltage generation circuit 31 is fixed is provided with either a variable mounting mechanism 44 or 62 that allows the mounting position of the crankshaft 22 to be changed in the circumferential direction relative to the cover 28b. Further, an indicator part 37 consisting of a scale is provided on the outer circumferential surface or end face of the flywheel 26, and the indicator part 37 is provided on a portion of the engine main body 20 or the cover 28b that faces the indicator part 37.
A small engine, characterized in that it is provided with a through hole 34 for visually confirming the position on the indicator 37 from the outside, and an indicator 36 consisting of a pointer for indicating the position on the indicator 37.