JPH048246Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to a two-stroke engine.

[Conventional technology]

FIG. 4 is a sectional view showing the main parts of a conventional two-stroke engine. When an engine is installed in a plurality of types of rods in a brush cutter (not shown), the rods have different rigidities and dimensions, and the vibrations at the parts that come in contact with the human body are not necessarily the same. As a countermeasure, we are considering adjusting the pitch of the bearing on the rod side, but this invention relates to the case where the countermeasure is taken on the engine side.

One of the main causes of vibrations on the engine side when a small two-stroke engine is attached to a brush cutter is thought to be the positional relationship between the center of gravity of the engine rigid body and the center of excitation force.

Figure 4 shows a structure type that is better for the current center of gravity position of the engine. In the figure, 1
is the drive side case, has a cooling air inlet 2, and has a cooling air inlet 3.
1 is a fan case, which is connected to the drive side case 1 and forms a compartment for accommodating a fan 4 which also serves as a cooling fan and a clutch support. 5 is clutch, 6
is a crankshaft, 7 is a flywheel magnetrotor, and 8 is an ignition coil.

[Problem that the invention attempts to solve]

As for the engine itself, even if the ignition coil 8, flywheel magnetrotor 7, and fan 4 are arranged with balance in mind, the vibration problem is still not solved in the type where the rod dimensions vary greatly.

[Means for solving problems]

The purpose of the present invention is to focus on the above points, and to provide an engine that allows engine-side parts to be easily changed to the optimum center of gravity position for the entire brush cutter system when the structure of the pole changes significantly. The feature of this is that in an engine in which an aluminum alloy or plastic cooling fan is installed on the output shaft side of the crankshaft and a flywheel magnetrotor is installed on the other end, the cooling fan is located at the center of gravity. It is made by integrally molding a steel weight for position adjustment.

[Effect]

In this case, the center of gravity position can be easily changed by changing only the fan. Furthermore, since the fan's internal weight is only changed and the external shape is not changed in any way, there is no problem with installation.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a cross-sectional view showing the main parts of a two-stroke engine according to an embodiment of the present invention, Fig. 2 is a plan view of the fan showing the main parts in cross-section, and Fig. 3 is a cross-section including the axis of the fan. It is a diagram.

In the figure, 1 is a drive side case in which a cooling air inlet 2 is bored, 3 is a fan case, 5 is a clutch, 6 is a crankshaft, 9 is a cooling fan attached to the output end side of the crankshaft 6, and 7 is a fan case. is a flywheel magnetrotor attached to the opposite side of the crankshaft 6, and 8 is an ignition coil. The cooling fan 9 made of die-cast aluminum or plastic is constructed by integrally molding a ring-shaped or steel weight 10 arranged symmetrically about the center of rotation.

The operation in the case of the above configuration will be described.

When set in the brush cutter, if the optimum center of gravity position is closer to the cooling fan than the current center of gravity position, the center of gravity can be moved closer to the optimum position by replacing the heavy weight 10 with the cooling fan 9, which is cast inside. It is possible. On the other hand, if it is on the anti-cooling fan side, it can be brought closer to the optimal position by making it lighter.

[Effect of idea]

The above case has the following effects.

When setting the center of gravity to the optimal position, the center of gravity can be adjusted by simply replacing the optimal weight with an integrally molded cooling fan, without changing or changing any other parts. Furthermore, since the weight of the steel weight integrally molded inside the cooling fan by casting or the like is changed, the external dimensions of the cooling fan remain unchanged and there is no need to expand the mounting space.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the main parts of a two-stroke engine according to an embodiment of the present invention, Fig. 2 is a plan view showing the main parts of the fan in cross section, and Fig. 3 is a cross-section including the axis of the fan. 4 are cross-sectional views showing the main parts of a conventional two-stroke engine. 5...Clutch, 6...Crankshaft, 7...Flywheel magnetrotor, 9...Cooling fan, 10...Weight.

Claims (1)

[Scope of utility model registration request] In an engine in which an aluminum alloy or plastic cooling fan is attached to the output shaft side of the crankshaft and a flywheel magnetrotor is attached to the other end, the cooling fan has an integrally molded steel weight for adjusting the center of gravity. A 2-cycle engine that is characterized by