JPS6323552Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a four-stroke internal combustion engine.

A 4-stroke engine is equipped with a valve mechanism, and on the other hand,
When the crankshaft is cantilevered, the cylinder block and crankcase are integrally molded, and the crankcase has at least an opening in the direction of the crankshaft axis and is closed with a cover, the explosion load of the engine must be considered. It is necessary to increase the strength and rigidity of the cylinder block, which may result in increased wall thickness and weight.

The present invention was made mainly to improve the above points, and its purpose is to integrally mold the crankcase part and the cylinder block part, and to improve the push rod of the valve mechanism that communicates with a part of the crankcase part. The cylinder housing is integrally attached to the crankcase portion so as to be substantially parallel to the cylinder block portion, and the housing is integrally provided with the cylinder block portion so as to be continuous with a portion of the cooling fins of the cylinder block portion. An object of the present invention is to provide an internal combustion engine in which the strength and rigidity of the engine are increased and the thickness of the cylinder block is made thinner, thereby making it possible to reduce the weight of the engine.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The drawing is a longitudinal sectional view of an internal combustion engine, and in the embodiment, the crankshaft is vertically installed and includes a cantilevered crankshaft. The internal combustion engine 1 is obtained by integrally casting a cylinder head part 2, a cylinder block part 3, and a crankcase part 4. The opening 5 extends from the base end of the cylinder block 3 to the crankcase 4.
It is formed from the inner diameter of the cylinder to the outer bottom 4a, and is closed with a cover 6 made of steel plate or the like. A piston 7 is slidably fitted horizontally within the horizontal cylinder inner diameter portion 3a of the cylinder block 3, a spark plug 8 is obliquely mounted on the cylinder head 2, and an intake/exhaust passage is provided in the center. A valve 9 (only one shown in the figure) is provided to open and close the combustion chamber and the combustion chamber.
A stem 9a of the valve 9 protrudes outward from the head portion 2, and its protruding end engages with one end of a valve rocker arm 10, and the other end of the rocker arm 10 engages with one end of a push rod 11 disposed in the direction of the cylinder axis. It matches. A support part 4b extending downward is provided at the outer part of the cylinder block part of the crankcase part 4, and a first bearing part 4c is provided at the upper part of the support part 4b and at the extension part of the inner diameter part of the cylinder. A second bearing portion 4e is provided on the end wall 4d and spaced apart from it in the axial direction. A push rod housing part 12 is integrally provided on the cylinder block side between the bearing parts 4b and 4d so as to be parallel to the axial direction of the block part 3. One end of the passage 12a in the housing part 12 communicates with the support part 4a in the crankcase part, and the other end opens onto the head part 2.

The wall 12b of the housing part 12 on the side of the cylinder block part 3 is continuously integrated with parts 2c and 3c of the cooling fins 2b and 3b which are integrally provided on the outer periphery of the cylinder block part 3 and the cylinder head part 2, and The cylinder block part 3 is integrated with the housing part 12 extending from the crankcase part via cooling fins, and its strength and rigidity are improved. Therefore, the cylinder block part 3 can be made thinner and lighter. can.

The piston 7 is connected to the small end of the connecting rod 13, and the large end of the connecting rod 13 is connected to the pin part 14a of the cantilever crankshaft 14, and the cylinder head part 2, cylinder block part 3, and crankcase part 4 are integrally cast. However, since the opening 5 is oblique, machining of the cylinder inner diameter portion 3a and bearing portions 4c and 4d can be easily performed. Pin part 1 of crankshaft 14
A first journal portion 14d adjacent to the web 14b of the shaft portion 14c extending downwardly from the web 14b adjacent to the shaft portion 4a is supported by the bearing portion 4c via a bearing 15, and a second journal portion 14d near the end of the shaft portion 14c is supported by the bearing portion 4c via a bearing 15. The journal portion 14e is supported by the bearing portion 4d via a bearing 16, the end of the shaft portion 14c extends outside the end wall 4d to serve as an output portion 14f, and the outside of the bearing 15 is an oil seal 16a.
It is sealed with.

Bearing 1 of shaft portion 14c of crankshaft 14
A gear part 17 is formed on the outer periphery between 5 and 16, and the gear part 17 meshes with a gear part 19 of a camshaft 18 disposed perpendicularly to the shaft part 14c. It passes through the passage 12a in the housing 12, and the other end of the passage 12a is connected to the lifter 2.
0 to engage with the cam portion 18a of the camshaft. The lower part of the camshaft 18 is approximately half submerged in the oil 21 stored on the bottom of the crankcase portion 4, and the lifter 20 has a cap shape, and a breather hole 22 is provided in a portion near the bottom of the lifter 20.
8a and the lifter 20 are in eccentric contact with each other, and the push rod end engages with the inner bottom of the lifter 20 so as to be swingable and rotatable. Therefore, the lifter 20 is rotated by the drive of the cam part, and on the other hand, a cover 23 is provided on the cylinder head 2, and an atmosphere communication hole 23a is provided in a part of the cover 23, so that the hole 22 of the lifter 20 is connected to the oil 21. When the oil is above the oil level, the inside of the crankcase is communicated with the outside air through the passage 12a and the communication hole 23a of the cover 23, and a breather effect can be performed without requiring a special passage. At this time, the oil flowing down inside the passage 12a is collected.

In the above embodiments, the head part, cylinder block part, and crankcase part were integrally molded, but the head part may be molded separately. Also, although the embodiment shows an overhead valve, a side valve type can also be used. It can be implemented, and it can also be implemented in a horizontally mounted crankshaft type.

As is clear from the above, according to the present invention, the cylinder block part and the crankcase part are integrally molded, and the push rod housing part and the crankcase are integrally molded, and the cooling fins are connected to the cylinder block part. Since it is integrated, the cylinder block part is reinforced by the push rod housing part, which increases the strength and rigidity of the cylinder block part.This allows the cylinder block part to be made thinner and lighter. The number of external structural members of the engine is reduced, which has the advantage of reducing the number of parts, simplifying the structure, and reducing costs.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional side view of an internal combustion engine showing an embodiment of the present invention. In the drawings, 1 is an internal combustion engine, 3 is a cylinder block part, 4 is a crankcase part, 12 is a storage part, and 3 is a cylinder block part.
b and 3c are cooling fins.

Claims (1)

[Scope of utility model registration request] A cylinder block portion whose axial direction is approximately horizontal, and a crankcase portion whose axial direction is approximately vertical are integrally molded, and the upper surface of the crankcase portion is opened diagonally so that it can be opened and closed, and the cylinder block portion is slidable in the approximately horizontal direction. A vertical internal combustion engine comprising a cantilevered crankshaft arranged substantially vertically,
A camshaft driven by the crankshaft and the crankshaft are provided in a direction perpendicular to each other on the cylinder block side in the lower part of the crankcase portion, and a camshaft is provided in the camshaft housing portion and a cylinder head on the cylinder block portion. A housing portion for a push rod for driving a valve mechanism is provided below the cylinder block portion so as to be parallel to the cylinder block portion, and the push rod housing portion and the cylinder block portion are connected to each other by cooling fins provided around the cylinder block portion. An internal combustion engine characterized by being integrally connected to each other.