JPS6346646Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to the structure of a valve seat cooling type exhaust valve.

Recently, with the increase in the output of internal combustion engines and the decline in the quality of fuel used, the heat load on exhaust valves has become increasingly severe, resulting in a tendency for high-temperature corrosion, accumulation of combustion residue, dents, etc. to occur on the valve seat. is strong, and this shortens the maintenance period for exhaust valves, making it a problem that cannot be overlooked when it comes to engine maintenance.

One of the countermeasures is to reduce the heat load on the exhaust valve by circulating cooling water near the valve seat of the exhaust valve, and the technical problem addressed by this invention belongs to this field. It is something.

8 and 9 show conventional valve seat cooling type exhaust valves. 1 is the valve stem of the exhaust valve, 2 is the valve box,
3 is a valve seat ring. The water chamber of the valve box 2 is divided into an inlet side water chamber 4 and an outlet side water chamber 5. The cooling water introduced into the inlet water chamber 4 flows through the hole 6 and the connecting pipe 7 into an annular cooling water chamber 8 formed in the valve seat ring 3. As shown in FIG. 9, there are three cooling water inflow passages from the water chamber 4 to the cooling water chamber 8. As shown in FIG. 9, the cooling water in the cooling water chamber 8 flows circumferentially from the right to the left in the figure, and then passes through three cooling water outflow passages to the connecting pipe 7, The hole 6 leads to the outlet side water chamber 5 of the valve box 2.

In the conventional cooling system having such a configuration, in order to effectively cool the valve seat portion 9, () the speed of the cooling water flowing through the annular cooling water chamber 8 is increased as much as possible to cool the cooling water chamber 8; Improves heat transfer.

() Bring the tip 8a of the annular cooling water chamber 8 as close to the valve seat 9 as possible.

It is necessary.

However, the requirement in parentheses is due to the fact that the flow path of the cooling water flowing through the cooling water chamber 8 is in the circumferential direction, so the length of the flow path becomes long. In this case, the pressure loss of the cooling water becomes large, and the cooling rate is limited to a certain constant value from this point, so it is not expected that the heat transfer effect will be improved by this means. In addition, the requirements in () apply to the valve seat ring 3.
As the wall thickness of this part is reduced, the mechanical stress and thermal stress in this part become high, which causes deformation or cracking in this part.

Furthermore, the cooling water in the conventional method flows in the cooling water chamber 8 in the circumferential direction from the right to the left in the figure, as indicated by the arrows in FIG.
During this time, heat is received from the valve seat seat 9, but the temperature of the cooling water in the cooling water chamber 8 is naturally lower on the right side and higher on the left side, and the temperature of the valve seat seat 9 is lower. This results in uneven deformation and unbalanced deformation, which impairs the tightness when the valve is closed.

The "exhaust valve device for an internal combustion engine" disclosed in Japanese Utility Model Application Publication No. 53-143934 as one of the prior art also belongs to the same device as the above-mentioned conventional method. Similarly to the cooling water chamber 8 described above, the chamber 2b has a structure in which cooling water flows in the circumferential direction in the water chamber to cool the valve seat, and as a result, the problem is exactly the same as that described above. The points remain unresolved.

This invention aims to solve all of the problems of the conventional devices mentioned above, by minimizing the pressure loss of the cooling water and increasing the cooling water velocity without sacrificing the strength of the valve seat ring. The cooling water chamber is brought sufficiently close to the valve seat seat, and the entire circumference of the valve seat ring is cooled by cooling water at a nearly uniform temperature, thereby improving the efficiency of cooling the exhaust valve seat. The object of the present invention is to realize an exhaust valve that is extremely effective in preventing accidents such as blow-through or damage to the valve seat.

For this purpose, the present device has a structure in which a valve seat ring is provided with an annular cooling water chamber for cooling the exhaust valve through the seat part, and the cooling water chamber of the valve seat ring is partitioned by a partition ring to form an annular cooling water inlet chamber. and annular cooling water outlet chambers are formed at concentric positions, and a large number of cooling holes with openings spanning both the cooling water inlet chamber and the cooling water outlet chamber are formed around the entire circumference of the cooling water chamber. A hole is formed at a position where the tip of the hole approaches the valve seat in the direction from the cooling water chamber toward the valve seat, so that the cooling water flowing into the cooling water inlet chamber passes through the cooling hole. Alternatively, a hanging wall that vertically bisects the upper part of the cooling hole is extended to the lower edge of the partition ring, and a cooling water passage is provided at the lower end of the hanging wall. It has a structure that forms a notch.

Next, the configuration of the present device will be specifically explained using drawings showing embodiments. 1 to 5 show one embodiment of the present invention, and numerals 1 to 7 and 9 are the same as those in the conventional apparatus shown in FIGS. 8 and 9. By partitioning the cooling water chamber built into the valve seat ring 3 by the partition ring 10, an annular cooling water inlet chamber 11 and an annular cooling water outlet chamber 12 are formed at concentric positions. 1
3, 13, . . . are cooling holes, the openings of which are bored around the entire circumference of the cooling water chamber at positions spanning both the cooling water inlet chamber 11 and the cooling water outlet chamber 12. The direction is the direction from the cooling water chamber toward the valve seat seat 9, and the depth is such that the tip of the hole approaches the valve seat seat 9. 14 is a connecting piece, which has one communicating hole 15 on its circumferential surface;
5 provides a cooling water inlet chamber 11 and a cooling water outlet chamber 12.
Either one of the two is connected to the upper communication pipe 7. In FIG. 1, the communication hole 15 of the communication piece 14 on the right side of the figure is communicated with the cooling water inlet chamber 11, and the communication hole 15 of the communication piece 14 on the left side of the figure is communicated with the cooling water outlet chamber 12, so that cooling is achieved. The water inlet chamber 11 is located on the outside and the cooling water outlet chamber 12 is located on the inside.However, if both the connecting pieces 14 are rotated 180 degrees and the position of the communicating hole 15 is reversed, the cooling water inlet chamber The inner and outer positions of the outlet chamber and the outlet chamber are reversed, and there is no problem with this embodiment.

To explain the effect of cooling the valve seat with the above-mentioned device, cooling water flowing into the inlet side water chamber 4 from the water supply port 16 (Fig. 4) flows through the three holes 6 to the connecting pipe 7 and then to the connecting piece. 14, the cooling water reaches the cooling water inlet chamber 11 through the communication hole 15 and is distributed around the entire circumference of the chamber 11. In this state, the cooling water in the chamber 11 generates a U-shaped flow as indicated by the arrows in FIG. The water flows into the outlet chamber 12 from the communication hole 15 of the communication piece 14 arranged on the left side in FIG.
and is led out to the outside of the valve box 2 through the drain port 17 shown in FIG. Therefore, the U-shaped flow of cooling water in the cooling holes 13 that are arranged around the entire circumference is entirely made of substantially isothermal cooling water, and there is no unevenness in temperature and cooling. Since the distance through which the cooling water flows through the holes 13 is extremely short, the flow path resistance is small and the flow velocity can be increased extremely easily.

FIG. 6 and FIG. 7 show another embodiment, and in this embodiment, the U-shaped flow generated in the cooling holes 13 in the above embodiment is configured to be forced to occur more reliably. It is. The partition ring 18 in this example has hanging walls 19 extending from its lower edge in a number corresponding to the number of cooling holes 13 . Hanging wall 1
A cutout 20 as a cooling water passage is formed at the lower end of the cooling water passage 9, and the cooling water flows from the cooling water inlet chamber 11 to the cooling water outlet chamber 12 only through the cutout 20. This aims to further increase the speed of cooling water. Therefore, the cooling hole 13
It is desirable that the bottom surface of the tip be formed into an arc shape that allows easy reversal of the cooling water and is suitable for cooling. Also,
It is desirable that the cutout 20 has a nozzle shape suitable for a cooling jet, thereby appropriately narrowing the passage cross-sectional area of the cooling water.

This devised device is constructed as described above, and as a result, the cooling hole as a cooling water chamber can be sufficiently approached to the valve seat portion without sacrificing the strength of the valve seat ring. In addition, it is possible to minimize the pressure loss of the exhaust valve while increasing the cooling water velocity.Furthermore, it is possible to achieve cooling with cooling water of almost uniform temperature around the entire circumference of the valve seat ring. It is extremely effective in improving cooling efficiency and preventing accidents such as blow-through or damage to the valve seat.

[Brief explanation of the drawing]

Fig. 1 is a sectional view taken along the - line in Fig. 2 of an embodiment of the present device, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 is a sectional view taken along the - line in Fig. 2. The cross-sectional view, Figure 4, is shown at - in Figure 1.
A cross-sectional view along the line, FIG. 5 is - in FIG. 2.
6 is a sectional view of another embodiment of the device of the present invention, FIG. 7 is a sectional view of the main part taken along the - line in FIG. 6, and FIG. 8 is a sectional view of the conventional device. 9
The figure is a sectional view taken along the - line in FIG. 1...Valve stem, 2...Valve box, 3...Valve seat ring,
4... Inlet side water chamber, 5... Outlet side water chamber, 6...
Hole, 7... Connecting pipe, 8... Cooling water chamber, 8a... Point, 9... Valve seat seat, 10, 18... Partition ring, 11... Cooling water inlet chamber, 12... Cooling water Exit chamber, 13...Cooling hole, 14...Connection piece, 15
... Communication hole, 16 ... Water supply port, 17 ... Drain port,
19... hanging wall, 20... notch.

Claims (1)

[Claims for Utility Model Registration] (1) A valve seat ring having an annular cooling water chamber for cooling the exhaust valve through the seat part, which has an annular cooling system by partitioning the cooling water chamber with a partition ring. A water inlet chamber and an annular cooling water outlet chamber are formed in concentric circles, and a large number of cooling holes are provided in the cooling water chamber, the openings of which span both the cooling water inlet chamber and the cooling water outlet chamber. Holes are drilled around the entire circumference in the direction from the cooling water chamber toward the valve seat seat, at a position where the tip approaches the valve seat seat, and the cooling water that flows into the cooling water inlet chamber flows through the cooling hole. A valve seat cooling type exhaust valve configured so that the cooling water flows into the outlet chamber via the valve seat. (2) A hanging wall that vertically bisects the upper part of the cooling hole through which cooling water flows from the cooling water inlet chamber to the cooling water outlet chamber is extended to the lower edge of the partition ring, and the hanging wall is extended to the lower edge of the partition ring. A valve seat cooling type exhaust valve according to claim (1) of the utility model registration, which has a notch formed at its lower end as a cooling water passage.