JPH0229234Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a sub-chamber structure for an engine, and in particular to an engine sub-chamber structure constructed by press-fitting a sub-chamber constituent member into a sub-chamber concave portion of a cylinder head. .

(Prior Art) Conventionally, as a subchamber structure of an engine, as described in, for example, Japanese Utility Model Application Publication No. 58-32127, a concave portion for the subchamber is provided in the cylinder head, and a first fitting portion in the upper part of the concave portion is provided. There is one in which the upper and lower ends of the sub-chamber forming member are press-fitted into the second fitting part at the lower part thereof, respectively, and a heat insulating recess is formed on the outer circumferential side of the sub-chamber forming member between the two fitting parts.

By the way, if the sub-chamber constituting member is press-fitted in two places, upper and lower, as in this kind of conventional sub-chamber structure, it becomes difficult to align the upper and lower press-fit fitting parts, causing various problems.

In other words, if the upper end or lower end of the subchamber component is formed to have a smaller diameter than the corresponding fitting parts, the sealing of the heat insulating recess will be insufficient, and carbon etc. will enter the heat insulating recess, causing the insulation of the heat insulating recess to deteriorate. sexuality will be lost.

In addition, the upper end or the lower end of the sub-chamber constituent member may be formed to have a larger diameter than the corresponding fitting portion, or the upper end and lower end of the sub-chamber constituent member or the first fitting portion and the second fitting portion may be formed to have a larger diameter than the corresponding fitting portion. If the center is eccentric, it may be difficult to press-fit the sub-chamber constituent member, it may not be possible to press-fit the sub-chamber constituent member to a specified depth, or it may be difficult to press-fit the sub-chamber constituent member to a predetermined depth. There are problems such as damage due to the action.

(Purpose of the invention) The present invention was made in view of the above-mentioned problems, and is designed to reliably press-fit the sub-chamber constituent members while absorbing machining errors of both fitting parts of the sub-chamber recess and the sub-chamber constituent members. It is an object of the present invention to provide a subchamber structure for an engine that is capable of performing the above operations and also ensures sealing performance.

(Structure of the invention) The engine sub-chamber structure of the present invention includes a first fitting portion in which the outer periphery of the upper end of the ceramic portion of the sub-chamber constituent member is press-fitted into the sub-chamber recess of the metal cylinder head; A second fitting part is formed into which the outer periphery of the lower end of the subchamber constituent member is press-fitted, and the first fitting part is formed between the two fitting parts.
In an engine sub-chamber structure in which a heat insulating recess is formed on the outer circumferential side of a sub-chamber constituent member with a step between the fitting part and the fitting part,
A plurality of convex portions and concave portions are arranged alternately in the press-fitting direction all around the inner wall of the first fitting portion.

(Effects of the invention) As described above, in the present invention, a plurality of convex portions and recesses are arranged alternately in the press-fitting direction all around the inner wall of the first fitting portion, so that when press-fitting the sub-chamber constituent member, , the upper end of the sub-chamber constituent member is formed to have a larger diameter than the first fitting part, or the axes of the upper end and lower end of the sub-chamber constituent member or the first fitting part and the second fitting part are Even if the cylinder head is out of alignment, since the cylinder head is made of metal and is softer than the ceramic part of the pre-chamber component, the above-mentioned uneven protrusions can be easily moved by the upper end of the ceramic part of the pre-chamber component. Since it is crushed and deformed, the sub-chamber forming member can be reliably press-fitted to a predetermined depth without applying unreasonable force to the sub-chamber forming member.

In this way, the sub-chamber constituent members can be reliably press-fitted while absorbing manufacturing errors of the sub-chamber constituent members and the concave portion for the sub-chamber, and the crushed convex portion can be reliably sealed, allowing the sub-chamber constituent members to Even if there is a slight gap between the upper end portion and the first fitting portion, sealing performance can be maintained due to the labyrinth effect.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal cross-sectional view of the pre-chamber structure of a diesel engine to which the present invention is applied, in which a pre-chamber recess 2 is formed in an aluminum alloy cylinder head 1, and a pre-chamber concavity 2 is provided with a sub-chamber component. 3 is press-fitted.

This auxiliary chamber constituent member 3 includes an integral ceramic main body 3a that surrounds the auxiliary chamber 4, a metal insert ring 3b that is fitted onto the lower end of the main body 3a, that is, the end on the nozzle hole 5 side, and a metal insert ring 3b that is fitted between these. A sub-assembly consisting of the inserted seal member 3c and a tension band 3d fitted to the outer periphery of the main body 3a with a predetermined tension applied thereto in order to increase the strength of the main body 3a. It is press-fitted into the recess 2.

The auxiliary chamber recess 2 is formed with a first fitting part 2a for press-fitting the outer periphery of the upper end of the main body 3a, and a second fitting part 2b for press-fitting the insert ring 3b. By making the diameter of the outer periphery of the sub-chamber concave portion 2 between the fitting part 2a and the second fitting part 2b larger than the main body 3a of the sub-chamber constituent member 3, the outer circumference of the sub-chamber constituent member 3 is reduced. A heat insulating recess 2c is formed on the side. The inner periphery of the heat insulating recess 2c is defined by the outer periphery of the main body 3a inserted into the auxiliary chamber recess 2.

As shown in FIG. 2, the first fitting portion 2a has a plurality of V-shaped annular recesses 6a and a plurality of annular protrusions 6b having a triangular chevron cross section alternately in the press-fitting direction of the sub-chamber forming member 3. Irregularities 6 arranged in rows are carved. Further, the circumferential surface of the first fitting part 2a below the unevenness 6 connects the upper end part of the sub-chamber constituent member 3 to the first fitting part 2a.
A guide surface 2d for guiding toward the center is formed in a tapered shape.

A guide surface 3e is also formed at the upper edge of the sub-chamber forming member 3 to facilitate press-fitting.

In order to further improve the degree of sealing of the heat insulating recess 2c, a sealing member 7 is installed between the peripheral edge of the upper end surface of the auxiliary chamber forming member 2 and the annular inner end surface of the auxiliary chamber recess 2 facing thereto.

In the above configuration, when press-fitting the sub-chamber forming member 3 into the sub-chamber recess 2, the convex portion 6 of the first fitting portion 2a
Since the degree of freedom in the radial direction increases due to the deformation of b,
While absorbing manufacturing errors of the sub-chamber forming member 3 and the sub-chamber recess 2, it is possible to reliably press-fit the main body 3a of the sub-chamber forming member 3 without applying unreasonable force.

In particular, when the cylinder head 1 is made of aluminum alloy, the protrusions 6b of the first fitting part 2a are easily crushed and deformed, and are sufficiently sealed by the plurality of protrusions 6b.

Even if the convex portion 6b is hardly deformed or a slight gap is created between the convex portion 6b and the subchamber component 3, the sealing performance is ensured by the labyrinth effect of the concave portion 6a and the convex portion 6b. Ru.

However, when the first fitting part 2a is structured as described above, the diameter of the upper end of the main body 3a of the sub-chamber forming member 3 to be fitted into the first fitting part 2a is determined in advance by the first fitting part 2a. It is desirable to set the diameter to a value larger than the inner diameter of the convex portion 6b of the joint portion 2a.

The present invention is not limited to the above-mentioned embodiment, but for example, as shown in FIG. Good too.

In the above embodiment, the unevenness 6 may be formed by annular grooving or by thread cutting.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a longitudinal cross-sectional view of the subchamber structure, FIG. 2 is an enlarged longitudinal cross-sectional view of the main part, and FIG. 3 is a modified example equivalent to FIG. 2. 1... Cylinder head, 2... Recess for sub-chamber, 2
a...first fitting part, 2b...second fitting part, 2c...
...Insulating recess, 3...Subchamber constituent member, 6a...Recess, 6b...Protrusion.

Claims (1)

[Scope of utility model registration request] A first fitting portion into which the outer periphery of the upper end of the ceramic portion of the auxiliary chamber component is press-fitted into the auxiliary chamber recess of the metal cylinder head, and a second fitting portion into which the outer periphery of the lower end of the auxiliary chamber component is press-fitted. In the sub-chamber structure of an engine, the first fitting part is formed with a fitting part, and a heat insulating recess is formed on the outer circumferential side of the sub-chamber constituent member with a step between the two fitting parts and the first fitting part. A pre-chamber structure for an engine, characterized in that a plurality of convex portions and concave portions are arranged alternately in the press-fitting direction all around the inner wall of the engine sub-chamber structure.