JPH0245452Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cooling structure for umbrella-shaped valves such as exhaust valves and intake valves used in internal combustion engines such as diesel engines and spark-ignition internal combustion engines.

A typical prior art is shown in FIG.
An umbrella valve 2 is provided in a cylinder head 1 of an internal combustion engine. This umbrella-shaped valve 2 includes an umbrella portion 3 and a valve stem 4. The top part 5 of the umbrella valve 2 is displaced downward in FIG. The inner circumferential surface of the valve seat 8 thus formed is separated from the valve seat surface 9 formed on the umbrella portion 3, and the valve is in an open state. The valve box 7 has a bush 10 that guides the valve shaft 4.
Then, a cylindrical guide member 11 that supports and surrounds the bush 10 is fixed. Coolant passages 12 and 13 are formed in the valve box 7 through which the coolant passes.
The coolant passages 12 and 13 are in partial contact with the outer peripheral surface of the guide member 11.

In the umbrella-shaped valve 2, a space 14 is formed extending from the umbrella portion 3 to the valve shaft 4. A hydraulic fluid 15 is sealed in a part of this space 14 . The hydraulic fluid 15 can become a gas during operation of the internal combustion engine. The hydraulic fluid 15 is heated and vaporized in the umbrella portion 3 and rises within the valve shaft 4 . The rising steam condenses on the inner wall of the valve stem 4, which is cooled by the coolant passing through the coolant passages 12 and 13 at the upper part of the valve stem 4. This condensed working fluid 15 descends along the inner peripheral surface of the space 14. In this way, the umbrella valve 2 is cooled using the latent heat of the hydraulic fluid 15. Therefore, the life of the valve seat 8 and the valve seat surface 9 is maintained, and the so-called vanadium attack phenomenon, which is corrosion caused by vanadium contained in low-quality heavy oil, is prevented.

In such prior art, sufficient heat dissipation cannot be achieved due to reasons such as the distance d from the surface of the valve stem 4 to the cooling water being large, or the flow rate of the cooling water in contact with the outer periphery of the guide member 11 being relatively low.
The umbrella valve 2 cannot be kept at a low temperature.

As another prior art technique for solving the above-mentioned problem, a bushing 10 has a coolant passage 20 inside it, as shown in FIG. 2, which has a shape in which the coolant passes through. There is. Since the coolant can approach the valve stem 4 and its flow rate can be relatively high, there is an advantage that sufficient heat dissipation can be derived from the valve stem 4.

Even in such prior art, the structure is relatively complicated because the cooling chamber 20 is provided inside the bush 10, and the material is limited to help the valve stem 4 slide, so manufacturing is not necessarily easy and the bush Even when the inner circumferential surface of the bushing 10 becomes worn, it is more expensive to replace than the conventional bushing.

In view of the above-mentioned problems, the purpose of the present invention is to effectively dissipate the heat transferred from the umbrella to the valve stem.
It is an object of the present invention to provide a cooling structure for an umbrella-shaped valve of an internal combustion engine that has a simple configuration and is advantageous even when it is replaced.

In the present invention, the working fluid 39 that evaporates in the umbrella part 31 and condenses in the valve stem 32 is in an airtight space 40 formed between the umbrella part 31 and the valve shaft 32 extending upward from the umbrella part 31. The valve stem 32 is inserted into a bush 33 that guides the valve stem 32 in a vertically movable manner, and an outward flange 41 is formed near the top of the bush 33. A plurality of flow grooves 42 extend in the axial direction below the flange 41 and above the lower end 33a of the bush 33.
are formed at intervals in the circumferential direction, a portion of the bush 33 below the flange 41 is inserted into a guide member 34, and the guide member 34 has a lower part and an upper part of the flow groove 42, respectively. Correspondingly, an annular inflow recess 43 and an annular outflow recess 44 are formed, and an annular recess 45 is formed between the inflow recess 43 and the outflow recess 44. The depth l1 is formed to be shallower than the depth l2 of the inflow recess 43 and the depth l3 of the outflow recess 44, and coolant passages 25 and 26 are formed in the valve box 22 attached to the cylinder head 21. Coolant flows in from an inflow pipe 50 provided through the valve box 22, and this inflow pipe 50 is connected to an inflow recess 43 via an inflow hole 47 formed in the guide member 34, and an outflow recess. 44 communicates with the coolant passages 25 and 26 via an outflow hole 46 formed in the guide member 34, and the valve box 22 has a mounting recess having a receiving portion 53 above the outflow hole 46 of the guide member 34. A flange 52 of the guide member 34 is attached to the receiving portion 53 within this attachment recess 51, and the flange 41 of the bush 33 is stacked on the flange 52 of the guide member 34. This is an umbrella-shaped valve cooling structure for internal combustion engines.

FIG. 3 is a sectional view of an embodiment of the present invention. A valve body 22 is attached to a cylinder head 21 of a diesel engine or a spark-ignition internal combustion engine.
This valve box 21 has a coolant passage 2 through which the coolant passes.
5 and 26 are formed.

The umbrella-shaped valve 30 basically includes an umbrella portion 31 and a valve stem 32.
including. The valve shaft 32 is guided up and down by a bush 33 fixed to the valve body 22. The bush 33 is reinforced and supported by a guide member 34.
The top 35 of the umbrella valve 30 is displaced downward in FIG. 3 against the force of a spring 36 by a cam mechanism operating in synchronization with the piston. As a result, the valve seat surface 38 of the umbrella portion 31 is separated from the inner circumferential surface of the valve seat 37 formed in the valve box 22, and the valve can be in an open state. In particular, according to the present invention, a plurality of flow grooves 42 are formed in the bush 33, which is of course easy to manufacture. 45 at intervals of depth l1, the flow grooves 42 function as cooling fins to increase the heat dissipation area and improve cooling efficiency. Further, according to such a configuration, the depth l
1 is formed by the annular recess 45, the pressure loss of the cooling fluid can be reduced. Generally, the coolant passage in an internal combustion engine is complicated and pressure loss tends to be large, but the present invention is advantageous in that it can minimize such pressure loss.

Furthermore, according to the present invention, the cooling liquid from the inflow pipe 50 enters the annular inflow recess 43 and enters the flow groove 42.
Through the annular recess 45, the cooling liquid is led from the outflow recess 44 through the outflow hole 46 to the cooling liquid passages 25, 26 formed in the valve body 22, and in this way, the bush 33 and the valve shaft 32 are sufficiently cooled. can do. This makes it possible to achieve a sufficient cooling effect due to the action of the working fluid 39.

Furthermore, in the present invention, a mounting recess 51 is formed in the valve box 22, and a flange 52 of the guide member 34 is mounted to the receiving portion 53 of the mounting recess 51. Furthermore, the flange 41 of the bushing 33 is overlapped within the mounting recess 51. Therefore, the leakage of the coolant from the vicinity of the outflow hole 46 of the guide member 34 can be prevented.
By lengthening the leakage path, leakage can be reliably prevented. Particularly near the umbrella valves of such internal combustion engines, the temperature is high and the heat contraction is relatively large, so it is important to prevent coolant leakage in such areas.
With the present invention, leakage of coolant can be reliably prevented.

An airtight space 40 is formed in the umbrella-shaped valve 30 from the umbrella portion 31 to the valve shaft 32. In the airtight space 40,
A cooling working fluid 39, at least a part of which becomes gas during operation of the internal combustion engine, is sealed. The remaining portion of the airtight engine 40 other than the portion in which the hydraulic fluid 39 is sealed is in a high vacuum.

FIG. 4 is a perspective view of the bush 33, and FIG. 5 is a sectional view taken along the cutting plane line -. The bushing 33 is generally cylindrical, and in order to guide the valve shaft 32 up and down, a flange 41 is formed near the top of the bushing 33 made of a material with good sliding properties, such as bronze. Flange 41 of bush 33
A plurality of flow grooves 42 extending in the axial direction are formed at equal intervals in the circumferential direction on the outer peripheral surface of the lower part.

FIG. 6 is a sectional view of the guide member 34. An annular inflow recess 43 is provided on the inner peripheral surface of the guide member 34.
and an annular outflow recess 44 are formed at intervals in the axial direction. The inflow recess 43 is formed near the bottom of the guide member 34, and the outflow recess 44 is formed near the top of the guide member 34. On the inner circumferential surface between the outflow recess 44 and the inflow recess 43, there is a gap between the inflow recess 43 and the outflow recess 44.
An annular recess 45 is formed throughout. Annular recess 4
The depth l1 of 5 is the inflow recess 43 and the outflow recess 4
It is formed shallower than the depths l2 and l3 of No. 4. A plurality of outflow holes 46 are formed in the outflow recess 44 at intervals in the circumferential direction. The inflow recess 43 has an inflow hole 4
7 is drilled. As shown in FIG. 3, the plurality of outflow holes 46 communicate with the coolant passages 25 and 26, and the inflow hole 47 communicates with an inflow pipe 50 provided in the valve box 22.

The bush 33 is inserted into the guide member 34, and a coolant passage 55 is formed, which is a space surrounded by the plurality of flow grooves 42 of the bush 33, the inflow recess 43 and the outflow recess 44 of the guide member 34, and the annular recess 45.
(See FIG. 3) is formed facing the outer peripheral surface of the bush 33. Coolant flows into the coolant passage 55 from the inflow pipe 50 through the inflow hole 47 . The coolant that has passed through the coolant passage 55 flows through a plurality of outflow holes 46.
The coolant is sent to the coolant passages 25 and 26 via the coolant passages 25 and 26.

Umbrella valve 3 for an internal combustion engine having the above configuration
In the cooling structure of No. 0, during operation of the internal combustion engine, the working fluid 39 is vaporized by the heat of the umbrella portion 31, and the valve shaft 3
Rise within 2. The vaporized working fluid 39 that has risen inside the valve shaft 32 has its latent heat removed by the cooling water passing through the cooling fluid passage 55, and is condensed. The condensed working fluid 39 travels down the inner peripheral surface of the airtight space 40 and returns to the umbrella portion 31 . In this way, the umbrella valve 3
0 cooling takes place. Since the coolant passage 55 is formed facing the outer peripheral surface of the bush 33, the distance from the valve stem 32 to the coolant is shortened, and heat dissipation from the valve stem 32 is improved. Furthermore, the heat transfer area is increased by the plurality of flow grooves 42 provided on the outer peripheral surface of the bush 33, and heat dissipation from the valve shaft 32 is enhanced. Since the depths 12 and 13 of the annular recess 44 are formed shallower, the flow rate of the coolant supplied to the coolant passage 55 can be improved.
The cooling effect can be improved. Furthermore, the structure is simple, which is advantageous when the bush 33 is replaced.

In the airtight space 40, the hydraulic fluid 39 flows into the umbrella portion 31.
It evaporates at the valve shaft 32 and condenses at the valve stem 32. Butsuyu 33
guides the valve shaft 32 so that it can move up and down. A plurality of flow grooves 42 are formed on the outer peripheral surface of the bush 33 below an outward flange 41 formed near the top of the bush 33.
2 extends above the lower end 33a of the bush 33 in the axial direction. A portion of the bush 33 below the flange 41 is inserted into the guide member 34. The inflow pipe 50 is provided to pass through the valve box 22, and is connected to the inflow recess 43 through an inflow hole 47 formed in the guide member 34, so that the cooling liquid flows therein.

A mounting recess 51 having a receiving portion 53 is formed in the valve box 22 above the outflow hole 46 of the guide member 34 . This receiving part 53 has a guide member 3
The flange 52 of the bushing 33 is superimposed on the flange 32 of the guide member 34 within the mounting recess 51.

As described above, according to the present invention, since the coolant passage is formed facing the outer circumferential surface of the bush, the heat transferred from the umbrella portion to the valve shaft can be efficiently dissipated. Furthermore, the structure is simple, which is advantageous when replacing the bush.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of a conventional cooling structure for an umbrella valve of an internal combustion engine, FIG. 3 is a cross-sectional view of an embodiment of the present invention, FIG. 4 is a perspective view of a bush 33, and FIG.
The figure is a sectional view taken along the cutting plane line - in FIG. 4, and FIG. 6 is a sectional view of the guide member 34. 30...Umbrella valve, 33...Butsuyu, 34...
Guide member, 25, 26, 55... coolant passage.

Claims (1)

[Claims for Utility Model Registration] In an airtight space 40 formed between the umbrella portion 31 and the valve stem 32 extending upward from the umbrella portion 31, evaporation occurs in the umbrella portion 31 and condenses on the valve stem 32. A hydraulic fluid 39 is sealed, and the valve stem 32 is inserted into a bush 33 that guides the valve stem 32 in a vertically movable manner.An outward flange 41 is formed near the top of this bush 33. A plurality of flow grooves 42 extending in the axial direction below the flange 41 and above the lower end 33a of the bushing 33 are provided on the outer circumferential surface of the bushing 33.
are formed at intervals in the circumferential direction, a portion of the bush 33 below the flange 41 is inserted into a guide member 34, and the guide member 34 has a lower part and an upper part of the flow groove 42, respectively. Correspondingly, an annular inflow recess 43 and an annular outflow recess 44 are formed, and an annular recess 45 is formed between the inflow recess 43 and the outflow recess 44. The depth l1 is formed to be shallower than the depth l2 of the inflow recess 43 and the depth l3 of the outflow recess 44, and coolant passages 25 and 26 are formed in the valve box 22 attached to the cylinder head 21. Coolant flows in from an inflow pipe 50 provided through the valve box 22, and this inflow pipe 50 is connected to an inflow recess 43 via an inflow hole 47 formed in the guide member 34, and an outflow recess. 44 communicates with the coolant passages 25 and 26 via an outflow hole 46 formed in the guide member 34, and the valve box 22 has a mounting recess having a receiving portion 53 above the outflow hole 46 of the guide member 34. A flange 52 of the guide member 34 is attached to the receiving portion 53 within this attachment recess 51, and the flange 41 of the bush 33 is stacked on the flange 52 of the guide member 34. Umbrella valve cooling structure for internal combustion engines featuring: