JPH0121162Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seat-cooled cylinder head for a diesel engine or the like, and particularly to a type of cylinder head in which each cylinder is provided with two or more exhaust valves.

In general, in diesel engines that burn low-quality fuel oil, a severe thermal load is applied to the exhaust valve, which may cause problems such as blow-through of the exhaust valve. As a countermeasure to this problem, conventional methods have been adopted, such as making the exhaust valve hollow and cooling it, and providing a cooling water chamber around the exhaust valve seat to cool the valve seat. However, when the conventional valve seat cooling method is adopted in an engine having two exhaust valves for each cylinder, the problem arises that the number of man-hours required for machining the cooling water path increases, reducing mass productivity.

That is, in the structure shown in FIG. 1, which is a schematic plan view, annular cooling water chambers 5 and 6 are provided around two exhaust valve seats 2 and 3 attached to the cylinder head 1. Each cooling water chamber 5, 6 has an inlet hole 7, 8, respectively.
and outlet holes 9 and 10 are provided. The inlet holes 7 and 8 are formed by cut holes opened obliquely upward from the lower surface of the cylinder head 1, and communicate with the tip of a common cooling water inlet passage 12. An intermediate portion of the passage 12 communicates with an outlet of a cooling water supply passage 13, and an inlet of the passage 13 communicates via a vertical hole 14 with a cooling water outlet of the cylinder block. The passages 12 and 13 are formed by cut holes formed from the side surface of the cylinder head 1. Since the structure shown in FIG. 1 is as described above, the passages 12 and 13, the inlet holes 7 and 8, and the outlet holes 9 and 10 must be formed individually with drill holes, which poses the problem of requiring time and effort to drill the holes. There is.

In the structure shown in Fig. 2, an inlet passage 12' and a vertical hole 14' are formed exclusively for the cooling water chamber 6 in addition to those for the cooling water chamber 5, so even with this structure, there is a problem in that it takes time and effort to drill the holes. .

The present invention aims to solve the above-mentioned conventional problems and is constructed as follows.

In other words, the cylinder head to which the present invention is applied is
First and second inlets of an exhaust port are provided around the fuel injection nozzle, and the exhaust port extends from both of the inlets generally along one side of the cylinder head, and the outlet is connected to the first and second inlets of the cylinder head. The first inlet is located farther from the end face than the second inlet and closer to the side face, and an annular exhaust valve seat surrounding each inlet of the exhaust port is provided in the annular shape of the cylinder head. It is fixed to the inner periphery of the boss, and has a structure in which annular first and second cooling water chambers are respectively formed between both exhaust valve seats and the boss.

In the cylinder head having the above structure, the cooling water inlet passage extends straight from the end face to the vicinity of the first inlet, generally along the exhaust port, at a position closer to the side than the second inlet. and closes the opening on the end face side of the cooling water inlet passage, and between the first inlet side end of the cooling water inlet passage and a first cooling water chamber around the first inlet. A first inlet hole connecting the two is provided in the wall portion concentrically with the cooling water inlet passage, and a wall between an intermediate portion of the cooling water inlet passage and a second cooling water chamber around the second inlet. A second inlet hole is provided in the wall between each cooling water chamber and the adjacent cooling water jacket inside the cylinder head, and an outlet hole is provided in the wall between each cooling water chamber and the adjacent cooling water jacket inside the cylinder head. A passage hole for connecting the cooling water outlet of the cylinder block and the cooling water inlet passage is provided in the end face side portion, and the cooling water inlet passage and each of the inlet and outlet holes are formed by cut holes. It is a feature. Next, embodiments of the present invention will be explained with reference to the drawings.

FIG. 3 is a partial horizontal cross-sectional view of the cylinder head 20, and FIGS. 4 and 5 are cross-sectional views, respectively. In FIG. 4, the exhaust valve seat 22 on which the first exhaust valve 21 is seated is fitted and fixed to the annular boss 24 of the cylinder head 20.
An annular first cooling water chamber 23 is formed between the seat 22 and the boss 24. The boss 24 is provided with a first cooling water inlet hole 25 communicating with the chamber 23, and the lower part of the cylinder head 20 is provided with a cooling water inlet passage 26 communicating with the inlet hole 25. The passage 26 is provided below the exhaust port 27.
A cooling water jacket 29 is provided between the cooling water jacket 7 and the passage 26. 30 is an end face of the cylinder head where the outlet of the exhaust port 27 opens, and a portion of the passage 26 near the end face 30 communicates with a vertical passage hole 31 on the lower side. The passage hole 31 is connected to a cooling water outlet 34 of a cylinder block 33 via a cooling water communication pipe 32. The passage 26 is formed by a borehole formed from the end face 30 , and the end of the passage 26 on the side of the end face 30 is closed by a screw plug 35 . Entrance hole 2
The reference numeral 5 is formed of a bored hole that is concentric with the passage 26 and has a smaller diameter than the passage 26.

In FIG. 3, 36 is a fuel injection nozzle, and around the nozzle 36, the first exhaust valve 21 and a second exhaust valve 41, which will be described later, are provided. The exhaust valve 21 is located farther from the end face 30 than the exhaust valve 41 is. 37
is the side surface of the cylinder head extending along the exhaust port 27, and the exhaust valve 21 is located on the side surface 3 compared to the exhaust valve 41.
It is located near 7. The passage 26 is located closer to the side surface 37 than the exhaust valve 41, and the center of the passage 26 and the inlet hole 25 is located closer to the side surface 37 than the center of the exhaust valve 21.
It's off to the side.

A second cooling water inlet hole 43 is provided in the middle of the passage 26.
is provided. As shown in FIG. 5, the inlet hole 43 communicates with a second annular cooling water chamber 46 around the second exhaust valve seat 45. As shown in FIG. A valve seat 45 is provided for the second exhaust valve 41 and is located on the annular boss 4 of the cylinder head 20.
7 is fitted and fixed. The inlet hole 43 is formed as a cut hole opened obliquely from the lower surface 49 side of the cylinder head 1. Sheet 4 against inlet hole 43
A cooling water outlet hole 50 is provided at a position diametrically opposite to 5.
is provided. Outlet hole 50 connects cooling water chamber 46 and cooling water jacket 29. Also, the exit hole 50
It is also formed with a cut hole opened from the lower surface 49 side. As shown in FIG. 3, the outlet hole 38 for the first cooling water chamber 23 is provided in the boss 24 at a position farthest from the side surface 37. Also, the exit hole 38 is also located on the lower surface 49.
(Fig. 4) It is formed by a cut hole opened from the side.

According to the above structure, about half of the cooling water flowing into the passage 26 from the outlet 34 of the cylinder block 33 shown in FIG.
After flowing into the cooling water chamber 23 through the cooling water chamber 23 and rotating inside the cooling water chamber 23 to cool the valve seat 22 during the cooling water chamber 23,
The cooling water is discharged from the outlet hole 38 in FIG. 3 into the cooling water jacket 29. The other cooling water in the passage 26 is
Flows into the cooling water chamber 46 through the inlet hole 43 in the figure,
After circulating in the cooling water chamber 46 and cooling the valve seat 45 during that time, it is discharged into the jacket 29 through the outlet hole 50.

Comparing the above embodiment with the structures shown in FIGS. 1 and 2, there are the following advantages in processing the cooling water path. That is, when machining the passage 26 and the inlet hole 25, there is no need to readjust the position of the center of the drill with respect to the cylinder head 20, and it is only necessary to replace the drill with a different diameter. Furthermore, the conventional cooling water supply passage 13 (FIGS. 1 and 2) is unnecessary, and only one vertical hole 31 on the inlet side is required. Therefore, in the above embodiment, the cooling water path can be easily processed.

Next, another embodiment will be explained with reference to FIGS. 6 and 7. In FIGS. 6 and 7, parts corresponding to those in FIGS. 3 to 5 are given the same reference numerals. In FIGS. 6 and 7, the cooling water inlet passage 26, the inlet hole 25, and the outlet hole 38 are coaxial and are formed by a cut hole opened from the end surface 30 side. Also passage 26
The centers of the holes 25 and 38 coincide with the center of the exhaust valve 21. The structure of other parts is shown in Figure 3~
It is similar to that in FIG.

According to the embodiment of FIGS. 6 and 7, the outlet hole 38
Since it can be formed with a drilled hole that is concentric with the inlet hole 25 and has the same diameter, that is, a common drilled hole, processing can be further facilitated.

As explained above, according to the present invention, two exhaust port inlets, that is, two exhaust valve seats 2
In the cylinder head 20 having 2.45,
Long cooling water inlet passage 2 which is the main passage of the cooling water path
Only one passage 6 needs to be provided, and the passage 26 can be used for both cooling water chambers 23, 46, and at least the cooling water inlet passage 26 and one inlet hole 25 can be formed by concentric cut holes. Furthermore, passage holes (inlet holes and outlet holes) other than the passage 26 are formed by partition-like parts (for example, the boss 47 between the passage 26 and the cooling water chamber 46).
It can be formed with a short cut hole.
Therefore, while simplifying the structure of the cooling water path,
It facilitates drilling holes for cooling water channels, improves mass productivity, and reduces manufacturing costs.

In addition, when embodying the present invention, the second cooling water chamber 4
It is also possible to form the inlet hole 43 and the outlet hole 50 of No. 6 with a single cut hole opened from the side surface 37 of the cylinder head.

[Brief explanation of drawings]

1 and 2 are schematic plan views of different conventional examples, FIG. 3 is a horizontal cross-sectional partial view of the embodiment of the present invention, and FIGS. 4 and 5 are - and - of FIG. 3, respectively.
6 is a partial horizontal cross-sectional view of another embodiment, and FIG. 7 is a cross-sectional view taken from FIG. 6. 20
... Cylinder head, 21, 41 ... Exhaust valve, 2
2,45...Exhaust valve seat, 23,46...Cooling water chamber, 24,47...Annular boss, 25,43...
Inlet hole, 26... Cooling water inlet passage, 27... Exhaust port, 29... Cooling water jacket, 30... Cylinder head end surface, 33... Cylinder block,
34...Cooling water outlet, 36...Fuel injection nozzle,
37... Cylinder head side surface, 38, 50... Outlet hole.

Claims (1)

[Scope of utility model registration request] First and second inlets of an exhaust port are provided around the fuel injection nozzle, and the exhaust port extends from both of the inlets generally along one side of the cylinder head, and the outlet is connected to one of the cylinder heads. The first inlet is located farther from the end face than the second inlet and closer to the side face, and an annular exhaust valve seat surrounding each inlet of the exhaust port is provided in the annular shape of the cylinder head. fixed to the inner periphery of the boss, respectively forming annular first and second cooling water chambers between both exhaust valve seats and the boss;
A cooling water inlet passage extending straight from the end face to the vicinity of the first inlet is provided at a position closer to the side surface than the second inlet, generally along the exhaust port, and the cooling water inlet passage is provided on the end face side and a first inlet hole connecting the first inlet side end of the cooling water inlet passage and the first cooling water chamber around the first inlet is provided in the wall between the first inlet side end of the cooling water inlet passage and the first cooling water chamber around the first inlet. A second inlet hole is provided concentrically with the cooling water inlet passage, and a second inlet hole is provided in a wall between an intermediate portion of the cooling water inlet passage and a second cooling water chamber around the second inlet, and connects the two; An outlet hole is provided in the wall between each cooling water chamber and the adjacent cooling water jacket inside the cylinder head to connect the two, and the cooling water of the cylinder block is provided in a portion closer to the end face than the second inlet hole. A seat cooling type cylinder head characterized in that a passage hole is provided for connecting the outlet and the cooling water inlet passage, and the cooling water inlet passage, each of the inlet holes and the outlet hole are formed by cut holes.