JPH0424117Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is an internal combustion engine using ceramics, specifically, it alleviates the stress at the joint between a metal cylinder liner and a ceramic head liner, and reduces the amount of combustion gas. The present invention relates to a coupling structure that prevents leakage.

[Prior Art] In the adiabatic internal combustion engine disclosed in Utility Model Application Publication No. 55-6479, ceramics are used in parts of the cylinder and piston in order to increase thermal efficiency without cooling the walls of the combustion chamber from the outside. There is. That is, the piston has a piston crown made of ceramic superimposed on a piston body made of metal, and is connected with bolts and nuts. Regarding the cylinder, the present applicant has already filed an application for a cup-shaped head liner made of ceramics that integrally includes a head portion that is connected to the lower surface of the head body and a cylinder portion that fits a piston.

However, by stacking a ceramic head liner on top of a metal cylinder liner with a gasket in between, the head body that supports the head liner is
Simply tightening the cylinder liner to the cylinder body that supports it with bolts does not provide perfect gas sealing at the overlapping joint, and when the engine is running, the head liner lifts up from the cylinder liner due to internal cylinder pressure, reducing the surface pressure of the gasket. However, there is a risk of combustion gas leaking. In addition, in the case of a multi-cylinder internal combustion engine,
If there is a difference in height (dimension in the cylinder center axis direction) between cylinders due to dimensional differences in parts such as cylinder liners and head liners, it will take time to correct.

Ceramic materials are highly brittle and easily crack or break under extreme unbalanced or large loads, so if there are dimensional errors in the parts, an excessive load will act on the head liner of a cylinder in a multi-cylinder internal combustion engine. Some cylinders may have loose gas or lubricant seals.

[Problems to be solved by the invention] In view of the above-mentioned problems, the purpose of the invention is to absorb the dimensional errors by an elastic sealing member during assembly, even if there is a dimensional error in the head liner or cylinder liner of each cylinder. Another object of the present invention is to provide a coupling structure between a cylinder liner and a head liner in which a gap is not created between the cylinder liner and the head liner due to the elastic force of the elastic sealing member.

[Means for solving the problem] In order to achieve the above object, the structure of the present invention combines a metal cylinder liner fitted into the cylinder body and an inverted cup-shaped ceramic head liner supported on the head body. At the section, a large-diameter cylindrical part is formed on the inner peripheral surface of the lower end of the head liner, a thin-walled cylindrical body that protrudes upward is formed on the end flange of the cylinder liner, and the thin-walled cylindrical body of the cylinder liner is connected to the large-diameter cylindrical part of the head liner. An elastic seal member having a cylindrical cross section is interposed between the end flange and the head liner.

[Function] In the present invention, a thin-walled cylindrical body formed at the end flange of a metal cylinder liner and projecting upward is fitted into a large-diameter cylindrical part formed on the inner circumferential surface of the lower end of a head liner made of Saramics. Even if the head liner changes up and down due to the explosion load, sliding occurs between the large-diameter cylindrical portion and the thin-walled cylindrical body, preventing combustion gas from leaking.

Even if combustion gas leaks from the fitting portion between the large-diameter cylindrical portion and the thin-walled cylindrical body, the elastic seal member ultimately prevents the combustion gas from leaking to the outside.

The elastic sealing material interposed between the end flange and the head liner flexes in response to the tightening force of the head bolt, thereby absorbing errors in the amount of tightening of the head bolt.

[Embodiment of the invention] As shown in FIG. 1, a piston constituting an adiabatic combustion engine according to the invention includes a piston body 30,
It consists of a piston crown 1, a bolt 2 and a nut 5 that connect the two. The piston body 30 is provided with a ring groove in the outer circumferential wall of the upper half thereof into which the piston ring 23a is fitted. The piston body 30 is integrally formed with a thick boss portion having a pin hole 19a inside the skirt 8 in the lower half. skirt 8
The pin hole 19a is connected to the connecting rod 41 by a piston pin.
are concatenated.

The piston body 30 is provided with a protrusion 21a on the outer peripheral side of the upper end surface 21 for guiding the impact ring 20. Further, the piston body 30 is formed with a column 15 projecting upward at the center of the upper end surface 21 and a deep annular groove 17 surrounding the column 15. The column 15 has a bolt insertion hole 14 formed in its upper end wall, and a cylindrical portion 18 formed below the upper end wall.

A piston crown 1 made of ceramics is provided with a recess 9 serving as a combustion chamber at the center of its upper end surface, and a cylindrical portion 16 that makes the entire wall thickness uniform is provided at its lower end surface. The axial length of the piston crown 1 is made to correspond to at least the piston stroke from top dead center until the temperature of the combustion chamber reaches its maximum.

A bolt insertion hole 13 is provided in a horizontal wall portion of the piston crown portion 1 that is partitioned by a recess 9 and a cylindrical portion 16. The bolt 2 extends from the recess 9 into the bolt insertion hole 13 of the piston crown 1, the bolt insertion hole 14 of the piston body 30, the separating cylinder 3 that abuts against the inner end surface of the cylindrical portion 18,
It is inserted into the washer 4 and the nut 5 is fastened.
The tightening force of the bolt 2 brings the inner end surface of the cylindrical portion 16 of the piston crown 1 into close contact with the column 15 of the piston body 30. The interior of the cylindrical portion 16 and the annular groove 17 is sealed by an impact ring 20 interposed between the lower end surface of the piston crown portion 1 and the upper end surface 21 of the piston body 30.

The insulating piston having the above-described construction is fitted into a metal cylinder liner 40 and a Saramics head liner 38. The head liner 38 is fitted into the cylindrical part 36 provided on the lower surface of the metal head main body 31 with a space between the head liner 38 and the head liner 38.
A gasket 37 is interposed between the inner end wall of the cylindrical portion 36 and the inner end wall of the cylindrical portion 36. That is, by connecting the head body 31 into which the cylinder liner 40 is fitted to the cylinder body with a head bolt, the cylinder liner 40 and the head liner 38 are sandwiched between them.

The head body 31 has a cylindrical body 4 connected to the intake port 35 and protruding downward from the inner end wall of the cylindrical portion 36.
4 are integrally formed. The cylindrical body 44 is fitted with the seal ring 34 and fitted into a positioning hole integral with the intake boat of the head liner 38, or more precisely, the valve seat 43. Although not shown, a similar cylindrical body is also formed at the exhaust port and is fitted into a positioning hole integral with the exhaust valve seat of the head liner 38.

In FIG. 1, the tip of the combustion injection nozzle 32 projects into the combustion chamber through a mounting hole in a head liner 38. As shown in FIG. 2, according to the present invention, a thin-walled cylinder 39 that projects upward is integrally formed on the end flange 40a of the cylinder liner 40. The thin cylinder body 39 is a head liner 38 made of ceramics.
It is fitted into a large diameter cylindrical portion 46 formed on the inner circumferential surface of the lower end. End flange 40a and head liner 38
An elastic seal member 42 is interposed between the two. Preferably, the inner peripheral surface 39a of the thin-walled cylinder 39 is a conical surface whose inner diameter gradually increases toward the upper edge. The thin-walled cylindrical body 39 is fitted into the large-diameter cylindrical portion 46 .

By screwing the head bolt inserted into the head body 31 into the cylinder body supporting the cylinder liner 40, the elastic seal member 42 is sandwiched between the cylinder liner 40 and the head liner 38.

As shown in FIG. 2, between the end flange 40a of the cylinder liner 40 and the head liner 38,
An elastic seal member 42 is interposed. As shown in FIG. 3, the elastic sealing member 42 is constructed by wrapping a leaf spring 49 around an annular core body 48 having a cylindrical cross section.
Constructed to absorb unreasonable loads applied to the
The elastic seal member 42 has a small spring constant and deforms following the increase or decrease in the distance between the head liner 38 and the cylinder liner 40.

Next, the operation of the coupling structure between the cylinder liner and the head liner according to the present invention will be explained. Dimension (especially height) errors between the head liner 38 and cylinder liner 40 are absorbed by elastic deformation of the elastic seal member 42 interposed at the joint between the head liner 38 and cylinder liner 40, and the head liner 38 made of ceramics absorbs excessive stress. I don't accept it.

The thin-walled cylindrical body 39 that projects upward from the end flange 40a of the cylinder liner 40 is connected to the head liner 3.
It is fitted into the large diameter cylindrical part 46 at the lower end of the cylinder 8, completely sealing the inside of the cylinder.

During operation of the internal combustion engine, even if the head liner 38 is displaced vertically due to cylinder pressure, an elastic seal member 42 is provided between the head liner 38 and the cylinder liner 40.
Sealed by.

[Effects of the invention] In the present invention, a thin-walled cylinder formed on the end flange of a metal cylinder liner and protruding upward is fitted into a large-diameter cylinder formed on the inner peripheral surface of the lower end of a ceramic head liner. Even if the head liner is displaced up and down under an explosive load, sliding will occur between the large-diameter cylindrical portion and the thin-walled cylindrical body, preventing combustion gas from leaking.

Even if combustion gas leaks from the fitting portion between the large-diameter cylindrical portion and the thin-walled cylindrical body, the elastic seal member ultimately prevents the combustion gas from leaking to the outside.

The elastic sealing material interposed between the end flange and the head liner flexes in response to the tightening force of the head bolt, thereby absorbing errors in the amount of tightening of the head bolt. Additionally, the resilient seal material absorbs dimensional tolerances between the head liner and cylinder liner and prevents the head liner from being subjected to excessive stress.

[Brief explanation of the drawing]

FIG. 1 is a front cross-sectional view of a coupling structure between a cylinder liner and a head liner according to the present invention, FIG. 2 is a front cross-sectional view showing an enlarged view of the same essential parts, and FIG. 3 is a front cross-sectional view of an elastic seal member. . 31...Head body, 39...Thin wall cylinder, 40
... Cylinder liner, 40a ... End flange,
42...Elastic sealing member, 46...Large diameter cylindrical portion.

Claims (1)

[Scope of utility model registration request] At the joint between the metal cylinder liner fitted into the cylinder body and the inverted cup-shaped head liner made of ceramic supported on the head body, a large diameter cylindrical part is formed on the inner peripheral surface of the lower end of the head liner, and the end of the cylinder liner is A thin-walled cylindrical body is formed that protrudes upward from the end flange, the thin-walled cylindrical body of the cylinder liner is fitted into the large-diameter cylindrical part of the head liner, and an elastic sealing member with a cylindrical cross section is interposed between the end flange and the head liner. A joint structure between a cylinder liner and a head liner.