JPH0218418B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cylinder head structure for an engine, and particularly to a structure for ensuring sealing between the cylinder head and a cylinder block.

[Prior Art] Generally, in a cylinder head that is connected to the cylinder block of an engine through a gasket, combustion pressure acts around the bore, so in order to ensure good sealing performance, the cylinder block (gasket) It is necessary to ensure sufficient surface pressure against the In particular, the combustion pressure from both bores acts between the bores of the cylinder head, so securing surface pressure is most important.

Therefore, as shown in Japanese Utility Model Application Laid-Open No. 53-123307, it has been proposed to increase the rigidity by casting a separate member into the lower deck between the bores of the cylinder head.

However, this method merely increases the rigidity of the lower deck between the bores of the cylinder head, so although it is effective in preventing the stress concentration of combustion pressure, the tightening force from the top deck due to tightening of the head bolt is not applied. First, there was a problem that the surface pressure between the bores could not be sufficiently increased.

This problem becomes even more important especially in modern engines that are aimed at increasing output, because the combustion pressure becomes extremely high.

[Object of the Invention] In view of this problem, the present invention effectively transmits the tightening force of the head bolt to the thick part around the bore, and
By reinforcing the thick wall around the bores between the bores, where stress is most concentrated, to ensure the necessary surface pressure and to ensure cooling performance for the area between the bores, which is under severe thermal conditions. It is an object.

[Structure of the Invention] In order to achieve the above object, in the present invention, a thick wall portion connecting the boss portions of the head bolt located between the bores of the cylinder head is connected to the cylinder head from the cylinder block formed between the bores. The communication path for guiding the cooling water is formed by branching inward in the width direction from the head bolt boss part so as to sandwich it from both sides, and the thick part between the head bolt boss parts is connected to the thick part around the bore. The basic feature is that the bores are connected together.

In other words, in the present invention, the thick part around the bore is connected and reinforced between the bores by the thick part connecting the boss part of the head bolt, and the tightening force of the head bolt is applied to the thick part around the bore through the thick part. The pressure is transmitted to the thick part, ensuring surface pressure between the bores.

Further, cooling water is supplied between the bores from the communication path between the two thick-walled portions.

[Effects of the Invention] Therefore, according to the present invention, the strength of the thick wall portion formed around the bore can be increased, and the surface pressure between the bores can be ensured, so that sealing performance can be effectively achieved. In addition, cooling water can be supplied between adjacent bores through the communication path between the two thick-walled parts, and the bores under severe thermal conditions can be effectively cooled. It is possible to ensure cooling between the bores.

[Example] Hereinafter, an example of the present invention will be specifically described with reference to the drawings.

As shown in FIG. 1, a cylinder head 4 is placed and fixed on a cylinder block 2 in which a cylinder bore 1 is formed through a gasket 3, thereby forming an engine body 5.

The cylinder head 4 is formed with a recessed wall 7 that defines a combustion chamber 6 together with the cylinder bore 1. An intake port 8 is opened from one direction in the recessed wall 7, and an exhaust port 9 is opened from the other direction. has been done.
These intake ports 8 and exhaust ports 9 are opened and closed by intake valves 10 and exhaust valves 11, respectively, and these intake and exhaust valves 10 and 11 are connected to the engine by a well-known overhead cam mechanism 12. , and are driven to open and close at predetermined timings. In FIG. 1, 13 is a cam cap, and 14 is a head cover.

As shown in the horizontal cross-section of the cylinder head in Fig. 2, a substantially circular thick-walled bore grommet portion 15 (thick-walled portion around the bore) surrounds the combustion chamber 6 (bore 1) in which the intake port 8 and exhaust port 9 open. is formed between adjacent combustion chambers 6 and 6 (between bores 1 and 1).
, a pair of head bolt boss portions 16 located on both sides with respect to the arrangement direction of the bores 1, 1, .
16 are connected in the width direction of the cylinder head 4 by a thick wall portion 17.

In this embodiment, the thick portion 17 includes a columnar rib 18 formed approximately at the center of the head bolt boss portions 16, 16, and an arcuate shape connecting the columnar rib 18 and each head bolt boss portion 16 at the lower part. It is constituted by a pair of connecting ribs 19, 19.

The columnar rib 18 is formed to connect the adjacent bore grommet portions 15, 15 at the portion where they are closest to each other, and each pair of connecting ribs 19, 19 connect the columnar rib 18 and the head bolt boss portion 16. are combined in an elliptical shape when viewed in plan, and as they approach the columnar rib 18, they are combined in an integrated state with the outer circumference of the bore grommet part 15, thereby forming a bore grommet part between the bores 1, 1. 1
Reinforce 5 and 15.

As shown in FIG.
are rigidly connected in the vertical direction with the head bolt boss parts 16, 16 to reinforce the space between both decks 20, 21, and to apply the tightening force of the head bolts 22, 22 that fasten and fix the cylinder head 4 to the cylinder block 2 to the top deck 21. Act on the lower deck 20 side from the side.

As seen in FIG. 2, the columnar ribs 18 have an elliptical cross section extending in the longitudinal direction of the cylinder head 4, and are configured so as not to obstruct the flow of cooling water in this direction.

Further, part of the tightening force acting on the head bolt boss portion 16 is transferred to the bore grommet portion 1 located between the bores 1 by the pair of connecting ribs 19, 19.
5, 15, thereby ensuring the necessary high surface pressure on the bore grommet portions 15, 15 in this portion.

As shown in FIGS. 2 and 3, the portions surrounded by each pair of connecting ribs 19, 19 are formed as water jackets 23, 24, and these water jackets 23, 24 are provided with cylinders. Communication passage 2 communicating with cooling water passages 25, 25 on the block 2 side
6 and 27 are provided to guide cooling water. It is preferable to provide water jackets 23, 24 as described above between the bores 1, 1 to guide cooling water, since the thermally severe area between the bores 1, 1 can be effectively cooled.

In Fig. 2, 28 is a spark plug mounting hole;
29, 29, . . . are other water jackets.

With the above configuration, the thick wall portion 17 connects the boss portions 16 located between the bores 1, 1, and the thick wall portion 17 and the bore grommet portions 15, 15 are connected. The rigidity of the portion between the bores 1, 1 of 15, 15 is increased, and it is possible to effectively prevent thermal fatigue and the occurrence of cracks associated therewith. Further, since the tightening force of the head bolt 22 is effectively transmitted to the bore grommets 15, 15 between the bores 1, 1 through the thick wall portion 17, a high surface pressure can be ensured.

Further, in the above embodiment, the thick portion 17 includes the columnar rib 18 that connects the lower deck 20 and the top deck 21 and each pair of connecting ribs 19, 19.
However, the present invention is not limited to this, and the point is that any structure in which the thick part connecting the head bolt boss part between the bores and the thick part around the bore are connected between the bores can be used. good.

Similarly, it goes without saying that the present invention is not limited to a valve train comprising an overhead cam mechanism.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of the main part of the engine, FIG. 2 is a horizontal cross-sectional view of the cylinder head, and FIG. 3 is a cross-sectional view along the - line of FIG. 1...Cylinder bore, 2...Cylinder block, 4
...Cylinder head, 15...Bore grommet part, 1
6...Head bolt boss part, 17...Thick wall part.

Claims (1)

[Claims] 1. A thick part formed around the bore, a head bolt boss part located between the bores, and a thick part connecting the head bolt boss parts located between the bores, the thick part is A communication path for guiding cooling water from the cylinder block to the cylinder head formed between the bores is formed by branching inward in the width direction from the head bolt boss portion so as to sandwich it from both sides,
An engine cylinder head structure characterized in that both thick walled parts are connected to each other between the bores.