JPS6345557Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an engine structure for a multi-cylinder engine capable of suppressing deformation of the cylinder block.

Conventionally, in the structure of a multi-cylinder engine, an aluminum alloy cover having a U-shaped cross section is fixed to one longitudinal end of a cylinder block, and a timing chain is housed between the one end of the cylinder block and the cover. A compact structure is known in which a cylinder head is fixed to the upper surface of the cylinder block and the upper surface of the cover via a gasket (for example, Lucie Legato Structure and Maintenance, 58, 60).
64 pages, published October 1978).

However, in the engine structure of the multi-cylinder engine described above, when the cylinder head is fixed to the upper surface of the cylinder block with a tightening bolt via a gasket, due to the tension of the tightening bolt and the surface pressure of the gasket, There is a problem in that bending moments M and M as shown in FIG. 1 act on the cylinder block 1, causing the cylinder block 1 to curve upward as shown by the dashed line in FIG. Due to the bending moments M and M, the cylinder bores 6, 7, 8, and 9 of each cylinder 2, 3, 4, and 5, which should originally be a perfect circle, are shaped into an elliptical shape, as shown by the dashed line in FIG. This causes problems such as uneven wear of piston rings, pistons, cylinder liners, etc., and gas leakage between the piston and cylinder liner.

By the way, if the cylinder block 1 is extended in the longitudinal direction, and the mating surface with the cylinder head is extended in the longitudinal direction, the bending moment N in the opposite direction to the bending moment M can be generated by the extended mating surface. If it acts on cylinder block 1,
Deformation of the cylinder block can be reduced. However, in this case, there is a problem that the longitudinal dimension of the cylinder block, that is, the engine dimension becomes longer.

Therefore, the purpose of this invention was to focus on the side wall of the storage chamber for the timing chain and timing belt.
By effectively utilizing this side wall, the engine structure of a multi-cylinder engine can be created that can prevent deformation of the cylinder block and prevent uneven wear of piston rings and gas leakage without increasing the engine size. The purpose is to provide new products.

The structure and operation of this device are such that both outer walls extending in the longitudinal direction of the engine of a cylinder block of a multi-cylinder engine, to which the cylinder head is fixed by a tightening bolt, are extended in the longitudinal direction of the engine to form a protruding wall. The upper surface of the wall is used as a mating surface with the cylinder head, and a flat cover is provided at the tip of the projecting wall, and the projecting wall and cover form a storage chamber for the timing belt or chain. without increasing the dimensions
The surface pressure acting between the projecting wall and the cylinder head generates a moment that reduces the deformation of the cylinder block, suppressing the deformation of the cylinder block, and preventing uneven wear of piston rings, etc. and gas leakage. It is characterized by the fact that it has been made possible to do so.

This invention will be explained in detail below with reference to illustrated embodiments.

As shown in Figures 3 and 4, the cast iron cylinder block 11 of the multi-cylinder engine has a cylinder head 1.
2 is fixed via a gasket 13 with a tightening bolt (not shown).

As shown in FIGS. 3 and 5, the cylinder block 11 has both outer walls 15 and 16 extending in the longitudinal direction of the engine connected to cylinder bores 17 and 18 of each cylinder.
... are lined up in the longitudinal direction, and the projecting walls 21, 2
2 is formed. On the other hand, the cylinder head 1
2, the upper surfaces 21a, 22a of the protruding walls 21, 22
The protrusion 23 can be brought into close contact with the gasket 13 through the gasket 13.
is formed. Therefore, the projecting wall 21,
The upper surfaces 21a and 22a of 22 are the cylinder head 12.
This serves as a mating surface for the lower surface 23a of the protrusion 23.

On the other hand, the tips 21b, 2 of the protruding walls 21, 22
2b, as shown in FIGS. 3 and 5, a flat cover 24 made of aluminum alloy is fixed with bolts 25, and the projecting walls 21, 22 and the cover 24 are fixed to each other with bolts 25.
A storage chamber 27 for the timing chain 26 is formed between the two.

In addition, in FIG. 4, 31 is a camshaft,
32 is a sprocket fixed to the camshaft 31 and wound around the timing chain 26, 33 is a piston, 34 is a piston ring, 35 is a water jacket, and 36 is a water pump.

In the engine structure of the multi-cylinder engine having the above configuration, as shown in FIG.
It is assumed that the cover 24 is fixed to the cylinder block 11 and the cover 24, and the cylinder head 12 is brought into close contact with the upper surface of the cylinder block 11 and the upper surface of the cover 24 via the gasket 13, and is secured by a tightening bolt (not shown).

At this time, the upper surfaces 21a, 2 of the protruding walls 21, 22
2a is a mating surface for the lower surface 23a of the protrusion 23 of the cylinder head 12, and is pressed downward by the lower surface 23a of the protrusion 23 through the gasket 13 as shown by the arrow X in FIG. Ru. Due to this pressing force (surface pressure) X, X, a bending moment similar to that shown in the arrow N in FIG.
The upward curvature of the cylinder block 11 is suppressed. Therefore, cylinder bores 17, 18,...
deformation of the piston ring is prevented, uneven wear of piston rings, etc. and gas leakage are prevented.

As is clear from the above explanation, the engine structure of the multi-cylinder engine of this invention is such that both outer walls of the cylinder block extending in the longitudinal direction of the engine are extended in the longitudinal direction of the engine to form protruding walls. Using the top surface of the wall as the mating surface with the cylinder head,
Since the surface pressure acting between the upper surface of the projecting wall and the cylinder head causes a moment to reduce the deformation of the cylinder block,
Deformation of the cylinder block and cylinder head can be prevented, and uneven wear and gas leakage of piston rings etc. can therefore be prevented. In addition, a flat cover is provided at the tip of the projecting wall, and the projecting wall and the cover form a storage chamber for a timing belt or chain, so even if the projecting wall is provided, Deformation of the cylinder block and cylinder bore can be prevented without increasing the engine size compared to conventional engines.

[Brief explanation of the drawing]

Fig. 1 is a front view of a cylinder block of a conventional multi-cylinder engine, Fig. 2 is a plan view of the cylinder block, Fig. 3 is an exploded perspective view of an embodiment of this invention, and Fig. 4 is an exploded perspective view of the above embodiment. The front view, FIG. 5, is a plan view of the end of the cylinder block. 11...Cylinder block, 12...Cylinder head, 21, 22...Protruding wall, 24...Cover, 27...Storage chamber.

Claims (1)

[Scope of utility model registration request] A projecting wall is formed by extending both outer walls extending in the longitudinal direction of the engine of a cylinder block of a multi-cylinder engine, the cylinder head of which is fixed to the upper part by a tightening bolt,
An end portion of the cylinder head is made to protrude from the upper surface of the protruding wall so that the upper surface of the protruding wall serves as a mating surface with the cylinder head, and a flat cover is disposed at the tip of the protruding wall, and the protruding wall and the cover are connected to each other. An engine structure of a multi-cylinder engine characterized by forming a storage chamber for a timing belt or chain.