JPS632571Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement of the swirl chamber structure of an internal combustion engine.

(Prior Art) Various proposals have been made in the past for configuring the lower swirl chamber of an internal combustion engine with a ceramic chamber cap fitted into a cylinder head holding hole. A nozzle is formed in this chamber mouthpiece, and since this nozzle must be accurately positioned with respect to the piston, it is also necessary to accurately position the chamber mouthpiece itself with respect to the cylinder head.

For this reason, conventionally, as shown in FIGS. 8 and 9, for example, a vertical groove 2' having a semicircular cross section is formed on the outer circumferential surface of a ceramic chamber cap 1', and a cylinder head 3' is correspondingly formed. A vertical groove 5' having a semicircular cross section is also formed on the inner peripheral surface of the holding hole 4', and a solid pin 6' having a circular cross section is formed between the circular cross sections formed by the vertical grooves 2' and 5'. By driving in the chamber cap 1', the chamber cap 1' is positioned (rotated) relative to the cylinder head 3'.

(Problem to be solved by the invention) However, in the conventional type, a solid pin with a small diameter is inserted between the circular cross section (2' and 5') formed across the chamber mouthpiece 1' and the cylinder head 3'. 6'
However, since it is inserted at an angle, it is difficult to accurately position it, resulting in poor workability. The present invention is intended to solve the above-mentioned problems, and uses a positioning member having a locking portion and a plate-shaped portion extending on both sides of the locking portion to assemble the chamber mouthpiece into the holding hole of the cylinder head. I'm trying to attach it.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a chamber cap 8 made of ceramic is fitted into the holding hole 6 of the cylinder head 2, and the inner peripheral surface of the holding hole 6 is fitted. A locking groove 11 extending in the axial direction of the holding hole 6 is formed in a part of the outer peripheral side of the chamber cap 8.
The chamber cap 8 corresponds to the locking groove 11.
A positioning surface 8a is formed which extends inward in the radial direction of the chamber cap 8 from the outer circumferential side of the chamber cap 8 and extends wider than the groove width of the locking groove 11 in the circumferential direction of the chamber cap 8, thereby positioning the chamber cap 8. Between the surface 8a and the inner circumferential surface of the holding hole 6 of the cylinder head 2, there is a locking part 13a that fits into the locking groove 11, and a locking part 13a that fits into the locking groove 11, and a locking part 13a that connects the holding hole 6 from both ends of the locking part 13a. a pair of plate-shaped portions 13b extending in an arc shape along the inner circumferential surface of the plate and abutting the positioning surface 8a;
The configuration is such that a positioning member 13 having the following is inserted.

(Function) Since the present invention has the above configuration, when assembling the chamber cap 8 to the cylinder head, the locking portion 13a of the positioning member 13 is connected to the locking portion 13a formed on the inner peripheral surface of the holding hole 6. Align the plate-shaped portion 13b along the groove 11, and then align the plate-like portion 13b with the positioning surface 8a of the chamber cap 8.
Insert it between the cylinder head 2 and the chamber cap 8 while following it. In the positioning member 13 inserted in this way, the plate-shaped portion 13b comes into contact with the positioning surface 8a of the chamber mouthpiece 8 to prevent rotation and position the chamber mouthpiece 8 within the cylinder head 2 (stop rotation). can.

Here, the positioning surface 8a of the chamber cap 8 is
Since the shape of the plate-like portion 13b is not restricted, it can be formed into a simple shape that is extremely easy to process, such as a planar shape or a smooth curved shape along the arc shape of the plate-like portion 13b.

If the positioning surface 8a of the chamber cap 8 is made into a smooth curved shape along the arc of the plate-like part 13b so that the entire surface of the plate-like part 13b of the positioning member 13 comes into contact with it, the prevention of rattling is improved. The chamber cap 8 can be positioned reliably. Furthermore, when inserting the positioning member 13, the positioning member 13 has a flat shape, so it is easy to hold and handle, and the locking part 13a of the positioning member is inserted into the locking groove 11, and the plate-shaped part 13b is inserted into the positioning surface 8a. Positioning member 1 while being guided
3 is inserted into the interval =12 without distortion, so
The chamber mouthpiece 8 can be positioned easily and accurately with respect to the cylinder head 2.

(Example) An example of the present invention will be described below based on the drawings.

In Fig. 1, 1 is a cylinder block, 2 is a cylinder head fixed on the cylinder block 1 via a gasket 3, 4 is a piston, and 5 is a main combustion chamber defined by these 1, 2, and 4. be.

A part of the cylinder head 2 has a main combustion chamber 5.
A holding hole 6 that opens on the opposing surface is formed, and a hemispherical upper chamber 7 of the vortex chamber is formed at the innermost part of the holding hole 6. The lower part of the holding hole 6 is a large diameter part 6a, into which a chamber cap 8 made of ceramic and having a bottomed cylindrical outer shape is fitted. Inside this chamber cap 8 is a lower swirl chamber 9 that cooperates with the upper swirl chamber 7 to form one swirl chamber. A nozzle 10 is formed which communicates with 5.

On a part of the outer peripheral side of the chamber cap 8, a second
As shown in the figure, the positioning surface 8 is a flat surface.
a is formed, and this positioning surface 8a is connected to the holding hole 6
It is formed along the entire length of the chamber cap 8 along the axial direction (vertical direction in FIG. 1). Opposed to the central portion of the positioning surface 8a in the circumferential direction of the chamber cap 8, the inner circumferential surface of the holding hole 6 has a cross section extending over the same length as the chamber cap 8 (the length of the large diameter portion 6a). A vertical groove 11 is formed as a semicircular locking groove.

A wedge-shaped pin 13 as a positioning member is inserted in a gap 12 (see FIG. 2) formed on the outer side of the positioning surface 8a of the chamber nozzle 8. This wedge-shaped pin 13 is formed as shown in FIG. 3 by pressing a spring steel plate. That is, a protrusion 1 as a locking part having a semi-cylindrical cross section with a diameter almost the same as the diameter of the vertical groove 11 is formed in the center.
3a and a pair of plate-like elastic parts 13b extending in an arc shape on both sides of the plate-like elastic parts 13a.
The upper end portion of the recess 13 is cut away to form a tapered portion 13c.

In such a wedge-shaped pin 13, both ends 13d of the pair of plate-shaped elastic parts 13b are in contact with the positioning surface 8a of the chamber cap 8, and the protruding part 13a is connected to the vertical groove 11.
It will be in a state where it is fitted inside. Therefore, the chamber cap 8 is positioned (rotated) with respect to the cylinder head 2 via the wedge-shaped pin 13,
The nozzle 10 can be accurately positioned relative to the piston 4. In this embodiment, the elastic force in the radial direction of the holding hole 6 of the plate-shaped elastic portion 13b of the wedge-shaped pin 13 causes the chamber cap 8 to
By absorbing the difference in thermal expansion between the chamber cap 8 and the cylinder head 2, wobbling of the chamber cap 8 is reliably prevented.

Here, the chamber cap 8 and the wedge-shaped pin 13
The assembly to the cylinder head 2 is performed before the cylinder head 2 is assembled to the cylinder block 1, but before this assembly, the wedge-shaped pin 13 having the tapered portion 13c has a wedge action (from the gap 12 to (The resistance force in the direction of coming out is large)
This reliably prevents the chamber cap 8 and wedge-shaped pin 13 from falling off from the cylinder head 2, and further effectively prevents the chamber cap 8 from wobbling.

4 and 5 show other embodiments of the present invention,
Components having the same functions as the components of the previous embodiment are given the same reference numerals, and their explanations are omitted (this also applies to the following embodiments).
In this embodiment, the positioning surface 8a is a tapered flat surface that extends from the axially middle part of the chamber cap 8 to the lower end and slopes toward the radially inward side of the chamber cap 8. , both ends 13d of the plate-like elastic portion 13b of the wedge-shaped pin 13 are shaped as shown in FIG.

6 and 7 show still another embodiment of the present invention, in which the positioning surface 8a is connected to the chamber base 8.
The tapered portion 13c of the plate-like elastic portion 13b of the wedge-shaped pin 13 is formed as a flat surface parallel to the axis from the axially intermediate portion to the lower end.
And both end portions 13d are shaped as shown in FIG.

Further, as can be seen from this embodiment, since the wedge-shaped pin 13 has an arc shape, it is easy to hold, difficult to deform, and can be easily assembled. Further, the positioning surface 8a of the chamber cap 8 may have a flat or smoothly curved shape because the plate-like elastic portion 13 of the wedge-shaped pin 13 comes into contact with the positioning surface 8a.
Processing has become extremely easy.

Further, since the wedge-shaped pin 13 has a simple structure, it can be easily manufactured by press working.

In this embodiment, the distal end 13d of the plate-like elastic part 13 is brought into contact with the positioning surface 8a of the chamber cap 8, but the positioning surface 8a is formed in an arc shape along the plate-like elastic part 13, and the positioning surface 8a is formed in an arc shape along the plate-like elastic part 13. It is also possible to make the entire surface of the plate-like elastic part 13 contact. and,
When the positioning surface 8a and the plate-like elastic portion 13 are brought into contact with each other over the entire surface in this way, the prevention of rattling is improved and the chamber cap 8 can be positioned more reliably within the holding hole 6.

Here, in order to confirm the effect of the present invention, particularly the effect on preventing cracks in the chamber cap 8, the following test was conducted. That is, the three embodiments of the present invention shown in FIGS. 1 to 7 and the conventional ones shown in FIGS. 8 and 9 are respectively
Applicable to cylinder diesel engine, each 4600rpm
Endurance operation was performed for 100 hours under full load. Also,
While four engines were prepared, a total of 16 test pieces were prepared, 4 each of the three embodiments of the present invention, the conventional one, and the chamber mouthpiece test pieces (3 types x 4 of the present invention, 12 pieces). , one type of conventional one ×
4), one type of chamber mouthpiece test piece was applied to all four engines. In addition,
Each chamber mouthpiece test piece was formed from a silicon nitride sintered body.

As a result of the above test, none of the 12 chamber cap test pieces of the present invention were cracked, but 2 out of 4 of the conventional ones were cracked.
Fine cracks were found in the vertical grooves 2'.

(Effects of the invention) The present invention has the advantage that between the positioning surface of the chamber mouthpiece and the inner peripheral surface of the holding hole of the cylinder head,
a locking portion that fits into a locking groove formed in the holding hole; a pair of plate-shaped portions that extend in an arc shape from both ends of the locking portion along the inner circumferential surface of the holding hole and abut against a positioning surface;
The chamber cap can be positioned by inserting a positioning member having a.

Since the positioning member has a simple structure consisting of a locking portion and an arc-shaped plate portion, it can be manufactured easily and inexpensively by press working.

In addition, since the plate-shaped portion of the positioning member is arc-shaped, the positioning surface of the chamber cap can also be formed in an arc-shape, making it easier to manufacture the chamber cap.
In addition, by bringing the entire surface of the locking portion of the positioning member into contact with the arc-shaped positioning surface, the backlash of the chamber cap is reduced, and more reliable positioning can be performed.

Furthermore, the positioning member is inserted into the gap formed between the cylinder head and the chamber mouthpiece without tilting while guiding the locking portion to the locking groove and the plate-shaped portion to the positioning surface. As a result, the chamber cap can be easily and accurately positioned with respect to the cylinder head, and the chamber cap can be quickly assembled to the cylinder head, improving work efficiency.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing one embodiment of the present invention, Fig. 2 is a sectional view taken along the line of Fig. 1, Fig. 3 is a perspective view of the wedge-shaped pin shown in Fig. 1, and Fig. 4 is a longitudinal sectional view of the present invention. 5 is a perspective view of the wedge-shaped pin shown in FIG. 4, FIG. 6 is a longitudinal sectional view showing still another embodiment of the present invention, and FIG. 7 is a perspective view of the wedge-shaped pin shown in FIG. FIG. 6 is a perspective view of the wedge-shaped pin shown in FIG. 6, FIG. 8 is a longitudinal sectional view showing a conventional example, and FIG. 9 is a sectional view taken along the line shown in FIG. 8. 2... Cylinder head, 6... Holding hole, 8...
Chamber cap, 8a...Positioning surface, 11...Vertical groove (locking groove), 12...Between, 13...Wedge-shaped pin (positioning member), 13a...Protrusion, 13
b...Plate elastic part.

Claims (1)

[Scope of utility model registration request] A chamber mouthpiece made of ceramic is fitted into a holding hole of the cylinder head, a locking groove extending in the axial direction of the holding hole is formed on the inner peripheral surface of the holding hole, and a part of the outer peripheral side surface of the chamber mouthpiece is formed. In correspondence with the locking groove, a positioning surface is formed that is drawn inward in the radial direction of the chamber cap from the outer circumferential side of the chamber cap and extends wider than the groove width of the locking groove in the circumferential direction of the chamber cap. A locking portion that fits into the locking groove is provided in a gap formed between the positioning surface of the chamber cap and the inner circumferential surface of the holding hole of the cylinder head, and a locking portion that fits into the locking groove and a locking portion that extends from both ends of the locking portion into the holding hole. A swirl chamber structure for an internal combustion engine, characterized in that a positioning member is inserted therein, the positioning member having a pair of plate-like parts extending in an arc shape along a circumferential surface and abutting the positioning surface.