JPH0210295Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling fan mounting device for an internal combustion engine, particularly a forced air-cooled general-purpose internal combustion engine.

Conventionally, in this type of cooling fan mounting device, a flywheel is fitted onto a rotating shaft such as the crankshaft of an internal combustion engine so as to prevent rotation using a key, etc., and a device for starting the cooling fan and recoil starter is attached to the side of the flywheel. It is known that the pulleys are stacked one on top of the other in that order and fixed together with a nut screwed into the rotating shaft, and the starting pulley, the cooling fan, and the flywheel are fixed to each other so that they do not rotate (for example, Japanese Patent Publication No. 58 -Refer to Publication No. 13735).

However, the conventional type mentioned above has a circular shaft hole (center hole) for the cooling fan located on the side of the flywheel.
Float the opening edge of the flywheel diagonally outward from the side surface of the flywheel and contact the bottom edge of the bottomed cylindrical starting pulley. Since the convex part formed on the circumferential surface of the circular boss part of the cooling fan engages with the convex part, there is a risk that the opening edge of the shaft hole of the cooling fan may shift in the axial or circumferential direction due to vibration, etc. There was an inconvenience that it could not be fixed in place. In particular, in the case of cooling fans made of synthetic resin, there is a risk that the concave-convex engaging portions with the flywheel may gradually deform and cause rattling.

The purpose of this invention is to simply and reliably fix the starting pulley, cooling fan, and flywheel, especially the cooling fan, to prevent rotation.
The configuration is as follows.

That is, a flywheel 2 is fitted onto a rotating shaft 1 such as a crankshaft of an internal combustion engine using a key 1a or the like so as to prevent rotation, and a cooling fan 3 is attached to a side surface of the flywheel 2.
In an internal combustion engine in which a starting pulley 4 and a starting pulley 4 are stacked one on top of the other in that order and fixed together by tightening with a nut 5 or the like screwed onto the rotating shaft 1, a non-circular protrusion 41 is provided around the shaft hole on the mounting bottom surface of the starting pulley 4. The projecting portion is formed to fit into the corresponding hole 31 of the cooling fan 3, which is formed to have approximately the same shape and size, and the starting pulley 4 and the flywheel 2 are engaged with each other in a concave and convex manner. The cooling fan 3 and the flywheel 2 are coupled to each other in a non-rotating manner, and the periphery of the corresponding hole 31 of the cooling fan 3 is sandwiched and fixed between the flywheel 2 and the starting pulley 4. .

The non-circular protruding part 41 of the starting pulley 4 may be an eccentric part with respect to the shaft hole 40, and although it is formed into a substantially triangular shape in the figure, it may be square, oval, or other suitable shape.

The corresponding hole 31 of the cooling fan 3 with respect to the non-circular protrusion 41 is formed to have approximately the same shape and size as the non-circular protrusion 41 and is fitted therein, and the peripheral portion of the corresponding hole 31 is connected to the starting pulley 4 and the flywheel 2. It is fixed in between.

Furthermore, the concave-convex engagement for preventing rotation between the starting pulley 4 and the flywheel 2 is such that the concave surface, which has approximately the same shape as the tip of the non-circular protrusion 41 of the starting pulley 4 is fitted, is connected to the axis of the flywheel 2. It is formed around the hole 20. Alternatively, as shown in the illustrated example, a protrusion 41a is formed on the non-circular protrusion 41, and the protrusion 41a
A recess 21 or hole may be formed in the flywheel 2 that engages with the flywheel 2 .

Incidentally, it is possible to prevent the fan 3 from flapping by providing concave and convex portions 22 and 32 that fit into each other on the peripheral portions of the flywheel 2 and the cooling fan 3, if necessary.

In Figure 1, 6 is the crankcase, 7 is the cylinder barrel, 8 is the fan cover, 9 is the recoil starter cover, 10 is the starter grip, 11 is the starter rope, 12 is the rope reel, 13 is the clutch pawl, and 14 is the starting pulley. The provided clutch pawl engagement hole is shown.

Since the present invention has the above configuration, the non-circular protrusion 41 formed on the starting pulley 4 is connected to the cooling fan 3.
At the same time, the non-circular protrusion 41 is engaged with a concave surface of a flywheel formed in substantially the same shape as the non-circular protrusion 41, or the protrusion 4
Simply by engaging the protrusion 41a formed in the flywheel with the recess 21 or hole formed in the flywheel, it is possible to connect the flywheel extremely easily and reliably in a non-rotating manner. Further, the non-circular protrusion 41 can be manufactured easily and inexpensively by, for example, being molded at the same time as the starting pulley 4 is press-molded, and the protrusion 41 can be easily and inexpensively manufactured.
The bottom surface of the starting pulley 4 on which it is attached to the flywheel can be reinforced by acting as a reinforcing rib.

Furthermore, since the peripheral portion of the corresponding hole 31 of the cooling fan 3 is sandwiched and fixed between the starting pulley 4 and the flywheel 2, the edge of the corresponding hole 31 may be axially or circumferentially damaged due to vibration or the like. The non-circular protrusion 41 and the corresponding hole 31 can be reliably maintained in a fitted state. Therefore, even when using a cooling fan made of synthetic resin, for example, the corresponding hole 31 that fits into the convex surface 41 is
This has the effect of preventing the parts from shifting and deforming, and stably fixing them against rotation for a long period of time.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a part of an internal combustion engine to which the cooling fan mounting device of the present invention is applied, and FIG. 2 is an exploded perspective view of the main parts thereof. 1 is a rotating shaft, 2 is a flywheel, 3 is a cooling fan, 31 is a corresponding hole, 4 is a starting pulley, 41 is a non-circular protrusion, and 5 is a nut.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A flywheel is fitted onto the rotating shaft of an internal combustion engine in a non-rotating manner, and a cooling fan and a starting pulley are stacked in that order on the side surface of the flywheel and attached to the rotating shaft. In an internal combustion engine that is fixed together with screwed nuts, etc., a cooling fan is provided in which a non-circular protrusion is formed around the shaft hole on the mounting bottom of the starting pulley, and the cooling fan is formed to have approximately the same shape and size as the protrusion. At the same time, the starting pulley and the flywheel are engaged with each other in a convex-concave manner to couple the starting pulley, the cooling fan, and the flywheel to each other in a non-rotating manner, and the surrounding area of the corresponding hole of the cooling fan is A cooling fan mounting device for an internal combustion engine, characterized in that it is sandwiched and fixed between a flywheel and a starting pulley. (2) The concave-convex engagement between the starting pulley and the flywheel is such that the tip of the non-circular protrusion formed on the starting pulley is fitted into the concave surface of the flywheel, which is formed to have substantially the same shape as the non-circular protrusion. A cooling fan mounting device for an internal combustion engine as set forth in claim (1) of the registered utility model. (3) The uneven fitting between the starting pulley and the flywheel is a registered utility model in which a protrusion formed on the non-circular protrusion of the starting pulley is engaged with a recess or hole formed on the flywheel. A cooling fan mounting device for an internal combustion engine according to claim (1).