JPH0210276Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is used in the technical field of reinforcing structures for cylinder heads of diesel engines.

(Prior Art) A conventional cylinder head for a same-flow type diesel engine is well known from, for example, Japanese Utility Model Application No. 59-13650. For example, as shown in Fig. 3, a conventional same-flow type cylinder head a has a subchamber b provided on one side, intake and exhaust ports c open on the other side, and a cylinder block g. It is attached to the top with a bolt (not shown). On the other hand, the cylinder head A, which is made of aluminum alloy casting, has large lumps concentrated around the subchamber B on one side and around the port C on the other side, and has high rigidity.
The middle deck f that partitions the water jacket d and the oil chamber e above the water jacket d in the middle portion thereof has low rigidity. Therefore, an upward force acts on the lower surface of the cylinder head a due to the explosive force in the cylinder h of the cylinder block g, and the thermal stress caused by this explosion causes the middle deck f to curve, and the vicinity of the pre-chamber b of the middle deck f is There was a problem in that stress was concentrated at the location i, and a crack was generated at the stress concentration location i.

(Purpose of the invention) The object of this invention is to provide a cylinder head structure that prevents the occurrence of cracks due to stress concentration as described above without significantly increasing the weight of the cylinder head.

(Structure of the invention) This invention is based on a cylinder head of a diesel engine that has a pre-chamber on one side and a port opening on the other side. Above, from the middle deck to the cam journal, and from the side wall on the side where the auxiliary chamber is provided (the one side) to the position where it wraps around the boss part of the port valve guide when viewed from the direction along the crankshaft. This is the structure of a diesel engine cylinder head that is provided with reinforcing ribs.

The cylinder head according to the structure of this invention has a reinforcing rib that connects the middle deck, the cam journal above the middle deck, and the side wall on one side of the head in the place where stress is concentrated, so that the cylinder head is protected against explosive force, thermal strain, etc. It can disperse stress and prevent the occurrence of cracks.

(Example) Hereinafter, an example of this invention will be described in detail with reference to FIGS. 1 and 2. In the following description, the terms "top and bottom" and "left and right" respectively mean the top and bottom in FIG. 1, and "front and back" mean the top and bottom in FIG. 2, respectively.

A cylinder head 1 of a diesel engine is provided with an auxiliary chamber 2 on one side (left side) of the cylinder head 1.
It is a same flow type with intake and exhaust ports 3 opening on the rear (right side) front and back.

4 is a water jacket 5 and an oil chamber 6 above it.
A middle deck 7 is a cam journal formed in the oil chamber 6. The cylinder head 1 has reinforcing ribs 9 extending vertically (-cut plane in FIG. 2) passing through the substantially vertical center line 2a of the pre-chamber 2 and extending in the width direction of the engine, that is, in the left-right direction when viewed from above the engine. are integrated. The lower end of this reinforcing rib 9 is continuous to the middle deck 4, the upper end is continuous to the cam journal 7, and the left end is connected to the side wall 6 of the oil chamber 6 on the subchamber 2 side.
a, and the right end extends to a position where the oil chamber 6 overlaps the boss portion 8a of the port valve guide 8 when viewed from the direction along the engine crankshaft (front-back direction, that is, the direction perpendicular to the plane of the drawing in FIG. 1). It stands out.

The auxiliary chamber 2 is provided with a fuel injection valve mounting hole 2b and a glow plug mounting hole 2c that are open to the outside, and the downward opening that communicates with each port 3 of the cylinder head 1 has a valve seat that abuts the port valve. A valve seat fitting hole 3a for fitting the valve seat is provided. 10 is a journal bearing of a camshaft, and 11 is an inner wall of a cylinder block to which this cylinder head 1 is attached.

The cylinder head 1 includes a fuel injection valve, glow plug, intake and exhaust port valves, their accessories, valve seats, etc. (all not shown), and is assembled on the top of a cylinder block (not shown). .

With the above configuration, when a diesel engine is operated, stress is generated in each part of the cylinder head 1 due to explosive force and thermal stress within the cylinder, but the reinforcing ribs 9 keep the middle deck 4 and the cam journal 7 together. The left end of the rib 9 is connected to the side wall 6a, and the right end extends so as to overlap the boss portion 8a of the port valve guide 8.
In both of these cases, the parts with high rigidity are connected by the ribs 9, the middle deck 4 is reinforced, and the secondary chamber 2 of the middle deck 4 with low rigidity is
The structure in the vicinity is also strong enough, and there is no risk of cracks occurring as in conventional structures.

(Effects of the invention) As mentioned above, this invention has been developed to provide the cylinder head of a diesel engine on a surface extending in the engine width direction through the center of the pre-chamber, between the middle deck and the cam journal, and from the side wall on the pre-chamber side. A reinforcing rib is provided between the valve guide and the boss of the port valve guide.
Without increasing the weight too much, the part of the middle deck near the sub-chamber, which has conventionally had low rigidity and where stress was concentrated near the high-temperature sub-chamber, is reinforced, dispersing stress and eliminating stress concentration.

[Brief explanation of the drawing]

Fig. 1 and Fig. 2 show an embodiment of this invention, Fig. 1 is a cross-sectional view taken along the - line in Fig. 2, Fig. 2 is a plan view taken along the - line in Fig. 1, and Fig. 3 is a conventional example. FIG. 1...Cylinder head, 2...Subchamber, 2a...
Center line, 3... Port, 4... Middle deck, 6
a...Side wall, 7...Cam journal, 8...Port valve guide, 9...Reinforcement rib.

Claims (1)

[Scope of utility model registration request] In a cylinder head of a diesel engine that has a sub-chamber on one side of the head and a port opening on the other side, a middle deck and a cam are located on a surface extending in the width direction of the engine passing through the center of the sub-chamber when viewed from above the engine. A cylinder head structure for a diesel engine, characterized in that a reinforcing rib is provided between the cylinder head and the cylinder head and between the one side wall and a position where the cylinder head wraps around a boss portion of a port valve guide when viewed from the direction along the crankshaft.