JPS6319574Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a cylinder block for an internal combustion engine, and more particularly to a cylinder block in which ribs are formed on the outer wall of the cylinder liner to sufficiently receive the forces of the cylinder head bolt and main bearing bolt. be.

Part of the explosive force generated during an explosion in the combustion chamber of an internal combustion engine is transmitted to the cylinder head, and the other part is transmitted to the crankshaft through the connecting rod, but the force transmitted to the cylinder head is The bolt is pulled, and the force transmitted to the crankshaft is transmitted from the crankshaft to the main bearing bolt via the main bearing.

That is, this explosive force causes the cylinder head bolt and main bearing bolt to be pulled together.

However, in general, the distance between a pair of cylinder head bolts arranged on the left and right sides of the crankshaft is usually larger than the distance between a corresponding pair of main bearing bolts.

That is, in conventional internal combustion engines, the water jacket provided on the outer periphery of the cylinder liner is quite large;
In particular, in a cylinder block structure in which a water jacket is provided from the top of the cylinder liner to the crankcase, the force of the cylinder head bolt is first transmitted to the outer wall of the water jacket, and then reaches the crankcase. The position is considerably outside the main bearing bolt, and the force is transmitted from there to the main bearing through diagonal ribs. Moment is generated at the bent point of this force transmission path, and stress is concentrated. There is a problem with the deformation of the cylinder block.
It is necessary to provide ribs that are strong and thick enough to accommodate this, which increases production costs and increases the weight between machines.

Therefore, the present invention was devised to solve the above problem, and by forming walls and ribs that transmit the force between the cylinder head bolt and the main bearing bolt as linearly as possible, the entire cylinder block The object of this invention is to provide a cylinder block that is free from deformation or stress concentration.

That is, in the present invention, the water jacket is formed only in approximately the upper half of the outer periphery of the cylinder liner of the cylinder block, and the water jacket is formed on the upper surface of the outer wall of the water jacket between each cylinder and on both sides of the crankshaft center on both sides thereof. Provide cylinder head bolt holes in each
Further, a rib is formed on the outer periphery of the cylinder liner, which connects the cylinder head bolt hole in the outer wall of the water jacket section almost vertically to the partition wall in which the main bearing bolt hole of the crankcase is provided.

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

First, FIGS. 1 to 4 show a cylinder block 1 of a two-cylinder internal combustion engine according to an embodiment of the present invention.As shown in FIG. Although the water jacket part 3 is formed, the cylinder head bolt holes 4 are provided at the upper part of the partition wall 9 in which the main bearing bolt holes 5 are provided, and at positions on both sides as close as possible to the crankshaft center K.

As a transmission path for the tightening force of the cylinder head bolt or the explosive force during engine combustion, the cylinder head bolt holes 4 are provided at the positions shown in FIG. 3 so as to be the outer wall 6 of the water jacket portion 3 at the top of the cylinder liner 2.
The gap between the water jacket 3 and the cylinder liner 2 is made as small as possible.

Next, approximately vertical ribs 8 corresponding to the positions of the cylinder head bolt holes 4 are formed on the outside of the wall of the cylinder liner 2 in the lower part of the cylinder liner 2 where the swimsuit part 3 is not provided. The rib 8 is formed continuously on the partition wall 9 between the two cylinders and the partition walls 9 on both sides thereof.

In the cylinder block 1 having the above structure, a wall 10 is provided along the inner surface of the boss portion of the cylinder head bolt hole 4 shown in FIG.
Transmitting the force of the cylinder head bolt to the wall 10,
The rib 8 is formed directly under the wall 10, and the force can be transmitted to the main bearing bolt in the main bearing bolt hole 5 located further inside, and the transmission path of the force is from the cylinder head bolt hole 4 to the main bearing bolt hole 5. becomes almost linear.

Therefore, in the cylinder block to which the present invention is applied, the path of the tensile force between the cylinder head bolt and the main bearing bolt becomes straight, there are no bends in the force transmission path, and the entire cylinder block is This is very advantageous in preventing deformation or stress concentration.

Another advantage of the present invention is that the weight of the cylinder block can be reduced.

The present invention can be effectively applied to cylinder blocks of water-cooled internal combustion engines.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of a cylinder block of an internal combustion engine according to an embodiment of the present invention, and FIG. 2 is an A of FIG. 1.
3 is a side sectional view taken along line B-B in FIG. 2, and FIG. 4 is a side sectional view taken along line C-C in FIG. 1. DESCRIPTION OF SYMBOLS 1... Cylinder block, 2... Cylinder liner, 3... Water jacket, 4... Cylinder head bolt hole, 5... Main bearing bolt hole, 6... Outer wall, 8...
...Rib, 9...Bulkhead.

Claims (1)

[Scope of utility model registration request] A water jacket is formed only on approximately the upper half of the outer periphery of the cylinder liner, and between each cylinder on the upper end surface of the outer wall of the water jacket, on both sides of the cylinders, on both sides of the crankshaft center, and on both sides of the main bearing. A cylinder head bolt hole is provided directly above the bulkhead in which the bolt hole is provided, and a cylinder head bolt hole is provided in the outer wall of the lower part of the cylinder block where there is no swimsuit part, in an almost vertical direction corresponding to the drilled part of the cylinder head bolt hole. A cylinder block for an internal combustion engine characterized by forming ribs.