JPS6022207B2 - Crankshaft device in engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to a crankshaft device for a small general-purpose internal combustion engine.

The applicant of this application previously proposed an engine of this type in which the crankcase is formed into an unseparated integral frame cliff shape by die-casting aluminum alloy or other means, but with such an engine, it is not necessarily easy to assemble the crankshaft. This results in a loss of workability.

The object of the present invention is to obtain a device free of such inconveniences, and a crankcase integrally molded with a cylinder barrel is provided with a pair of left and right bearing holes and a closing hole on the lower surface. Inserting the bending weight part, and inserting each straight journal part on both outer sides of the crankshaft from the bearing hole, and press-fitting the journal part into each shaft hole formed on the opposing surface of the weight part. It consists of

An example of implementing the present invention will be explained with reference to the attached drawings. In the drawings, reference numeral 1 indicates a crankcase, and reference numeral 2 indicates a cylinder barrel on the upper surface of the crankcase, and the case 1 and the barrel 2 are integrally formed in advance by die casting of an aluminum alloy, for example. Further, to describe the case 1 in detail, the case 1 is made into an integral frame lotus shape having a closure 3 on the lower surface and a pair of bearing holes 4 on both sides, and in this case, the bearing holes 4 , 4 are generally prepared by processing by fine boring or other methods. In the drawings, reference numeral 5 indicates a cylinder head fixed to the upper surface thereof, and reference numeral 6 indicates a removable cover plate provided to the lower surface thereof. Thus, the crankshaft 7 is to be incorporated into the case 1 which has the closure 3 on the lower surface, and the crankshaft 7 has a central bent weight part 7a and straight journal parts 7b, 7b extending on both sides of the weight part 7a. shall be prepared and separated in advance into at least three parts.

To assemble this, first insert the weight part 7a into the case through the opening 3 on the lower surface of the case, and then insert each journal part 7b through each bearing hole 4. The weight portion 7a is inserted and its respective tips are press-fitted into respective shaft holes 7c, 7c formed in advance on the opposing surface of the weight portion 7a.

In this case, the weight portion 7a is prepared in advance in a state where it is combined with the piston 9 via the connecting rod 8, and when the weight portion 7a is inserted into the case, the piston 9 is At the same time, the iron is fitted into the barrel 2. In this way, according to the present invention, the cylinder barrel 2 and the crankcase 1 integrally formed are provided with a pair of left and right bearing holes 4, 4 and an opening □ 3 on the lower surface, and the bent weight at the middle of the crankshaft is opened from the closed opening 3. At the same time, the journal parts 7b, 7b on both outer sides of the crankshaft 7 are inserted through the bearing holes 4, 4, and the journal parts 7b, 7b are inserted.
The shaft holes 7c, 7 formed on the opposing surface of the weight portion 7a
Since the crankshaft is inserted into the cylinder barrel, it is easy to roughly fit the crankshaft to the crankcase integrally molded with the cylinder barrel, and the workability can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS The drawing is a cut side view illustrating the silk-attaching operation of one example of the apparatus of the present invention.

1... Crank case, 3... Sekiguchi, 4, 4... Bearing hole, 7... Crankshaft, 7a... Weight part, 7b, 7b... Journal part, 2 ...Cylinder barrel, 7c...Shaft hole.

Claims (1)

[Claims] 1 A crankcase integrally formed with the cylinder barrel is provided with a pair of left and right bearing holes and an opening on the lower surface, and a bent weight part is inserted into the middle of the crankshaft through the opening, and
A crankshaft device for an engine, wherein straight journal parts on both outer sides of the crankshaft are inserted through the bearing hole, and the journal parts are press-fitted into respective shaft holes formed on opposing surfaces of the weight part.