JPS6120252Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a suction cooled internal combustion engine.

FIG. 1 is a sectional view of a conventional suction cooling type engine taken along the center line of the crankshaft, and FIG. 2 is a side view thereof. In this type of suction cooling type engine, a cooling fan 11 is attached to one end of the crankshaft 2 of the engine 100, and the cooling fan 11 is rotated to direct cooling air from the outside to the inside of the baffle plate 4 in the direction of arrow B. The engine 100 is cooled by suctioning the air into the air and discharging it from an exhaust port 5a provided on a part of the circumferential surface of the casing 5. 1 is engine 100
, 3 is a flywheel, 4 is a baffle plate fixed to the crankcase 1, and 5 is fixed to the baffle plate 4 by a plurality of bolts 13 arranged concentrically with the fan shaft 12. In order to increase the cooling efficiency of the cooling fan 11, a cooling air guide 5b is provided on the inner diameter side of the cooling fan 11. A hollow fan shaft 12 is fixed to the end of the crankshaft 2 on the flywheel 3 side, and the cooling fan 11 is integrally formed with the fan shaft 12. A recoil starter 8 is fixed to the casing 5 by a plurality of bolts 9 arranged concentrically with the fan shaft 12. The rotating portion 8a of the recoil starter 8 is adapted to be inserted into the hollow portion of the fan shaft 12. 8b
8 is a claw that is inserted into and removed from the hole 12a of the fan shaft 12;
c is a rope, and 8d is a knob.

The above-mentioned suction cooled engine has the following drawbacks.

(1) When attaching the casing 5 to the baffle plate 4, it was necessary to put one's hand inside the casing 5 and tighten the bolts 13, which made the work extremely difficult due to the narrow space.

(2) For the type in which the crankshaft rotates in the opposite direction to that shown in Figure 2, that is, clockwise when viewed from the flywheel 3 side, it is necessary to prepare another casing 5 that rotates clockwise, which increases the number of parts. There were flaws.

(3) The rigidity of the casing is weak.

The purpose of the present invention is to provide a suction cooling type internal combustion engine that eliminates the above-mentioned drawbacks, and its features are that both front and rear end surfaces are formed into flat plate shapes, and that the cooling fan shaft center opening on both end surfaces is formed into a flat plate shape. The casing has a diameter larger than the outer diameter of the cooling fan, and can be installed by changing both end faces according to the direction of rotation of the crankshaft. A cooling air guide for guiding cooling air inward of the casing, which is interposed between the two end faces of the casing around a hole coaxially drilled in both end faces of the casing, and a bolt for attaching the casing to the air guide plate. A hollow pipe is provided through which the bolt can be tightened from the outside of the rear end surface of the casing.

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

FIG. 3 is a sectional view showing a suction cooling type internal combustion engine according to an embodiment of the present invention.

Differences from the conventional one shown in FIGS. 1 and 2 will be explained.

A cooling air guide 20a that guides the cooling air toward the inside of the casing 21 is provided protruding from the air guide plate 20 at the periphery of the opening toward the axial center of the cooling fan 11.

The front end surface of the casing 21 on the baffle plate 20 side and the rear end surface on the recoil starter side are both formed of flat plates, and each has an opening 21a at the axial center of the fan 11.
The diameter of the fan 11 is larger than the outer diameter of the fan 11.

Also, the bolt 13 in FIG. 2, that is, the casing 21
Hollow pipes 22 are interposed between the two end faces around the holes drilled coaxially on both the front and rear end faces at the positions of the bolts that fix the front end faces of the front end faces to the baffle plate 20. In this example, four pieces are fixed. Furthermore, a nut 24 into which a through bolt 23 is screwed is fixed to the baffle plate 20 side by welding or the like.

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

To explain the assembly order, first, the cooling fan 11 is attached to the crankshaft 2, and then the recoil starter 8 is attached to the baffle plate 20 with bolts 23 through the casing 21, which has already been attached with bolts 9.

In this case, both end surfaces of the casing 21 are formed of flat plates, and the diameter of the opening 21a at the axial center of the fan 11 is larger than the outer diameter of the fan 11. Both end plates can be changed and installed depending on the direction of rotation.

The present invention as described above has the following effects.

Regardless of the direction of rotation of the crankshaft 2, the same parts can be used for the casing 21, and the cooling effect provided by the cooling air guide 20a provided on the air guide plate 20 can provide the same cooling effect as the conventional one.

Moreover, the rigidity of the casing 21 is greatly increased by the hollow pipe 22, and the casing 21 can be easily mounted from the outside of the rear end surface.

FIG. 4 is a sectional view showing a suction cooling type internal combustion engine according to another embodiment of the present invention.

In this case, by omitting the bolts 9 and tightening the recoil starter 8 and the casing 21 together with the through bolts 23, the number and position of the through bolts 23 may be set to, for example, the number and position of the bolts 9 shown in FIG. , the number of parts can be further reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional suction cooling type internal combustion engine, FIG. 2 is a side view of the engine shown in FIG. 1, and FIG. 3 is a sectional view showing a suction cooling type internal combustion engine according to an embodiment of the present invention. FIG. 4 is a sectional view showing a suction cooling type internal combustion engine according to another embodiment of the present invention. 1...Crank case, 2...Crankshaft, 8
... Recoil starter, 11 ... Cooling fan, 1
2...Fan shaft, 20...Air guide plate, 20a...Cooling air guide, 21...Casing, 22...Hollow pipe, 23...Through bolt.

Claims (1)

[Scope of utility model registration request] A cooling fan attached to the end of the crankshaft, a baffle plate fixed to the crankcase that forms a cooling air passage and opens to the axial center of the cooling fan, and a cooling fan installed on both front and rear end surfaces by destroying the fan. A casing is provided with an opening in the fan shaft center, a cooling air outlet in a part of the circumferential surface, and the front end surface is fixed to the baffle plate and the rear end surface is fixed to the disc-shaped recoil starter. In the suction cooling type internal combustion engine, both the front and rear end surfaces are formed of flat plates, and the diameter of the cooling fan axis opening on both end surfaces is formed to be larger than the outer diameter of the cooling fan, so as to correspond to the rotation direction of the crankshaft. A casing that can be attached by changing both end faces, a cooling air guide that protrudes from the opening periphery of the baffle plate toward the cooling fan axis and guides the cooling air inward of the casing, and a cooling air guide that guides the cooling air inward of the casing; A suction cooling type internal combustion engine, characterized in that it is provided with a hollow pipe that is interposed between the same end faces around a hole drilled in a shaft, and is capable of tightening a bolt for attaching the casing to the baffle plate.