JPS6340247B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a poppet valve used as an intake/exhaust valve of an internal combustion engine.

The part of a poppet valve that is most susceptible to damage is the surface that contacts the valve seat, and models in which this part is coated with metal such as stellite have been in use for quite some time.
Recently, however, in order to withstand even more severe operating conditions, the entire valve head has been made of high-grade alloys (such as Nimonik) and high-grade steels (such as austenite) that have excellent heat resistance, corrosion resistance, and wear resistance. In some cases, valve stems made of common steel material and pressed together have come to be used. However, although this pressure-welding type poppet valve can be made cheaper than when the entire valve is made of high-quality material, the area of the pressure-welded part is small, making it difficult to firmly connect it, and furthermore, the pressure-welded surface easily peels off. This has the disadvantage that the valve head may fall onto the piston, causing serious damage to the engine.

The object of the present invention is to obtain a new joint-type poppet valve that can solve these problems.

Therefore, in the poppet valve of the present invention, the outer circumferential edge of the canopy is formed of a material different from the valve body, with the annular joint surface extending from the front surface to the back surface of the cap portion as a border, and the diameter of the joint surface is It gradually becomes larger in the direction in which the joint surface extends, and furthermore, there is a step part perpendicular to the axis in the middle of the joint surface, and the diameter becomes smaller at this part.

According to the present invention, compared to the above-mentioned stem joint type valve, high-grade material is used only for the peripheral edge of the valve umbrella, so material costs can be reduced. In addition, the periphery of the umbrella is supported by the stepped part of the valve body, and the front side of the valve has a structure that essentially prevents it from slipping out, providing a high level of safety that cannot be achieved with conventional stem joint types. ing. Moreover, by increasing the diameter of the joint surface toward the back of the valve, the periphery of the canopy is prevented from slipping off to the back of the valve, and the valve body and the periphery of the canopy have a strong integrity. There is. Therefore, the joining surfaces do not necessarily need to be welded, and materials such as ceramics and fiber-reinforced metals, which cannot be or are difficult to weld with the metallic valve body, can be used for the peripheral edge of the umbrella. Furthermore, if a weldable material such as austenitic steel is used for the peripheral edge of the umbrella and welded to the valve body, an extremely strong joint can be obtained because the welding area is large.

To further explain this invention with examples, FIG. 1 shows a poppet valve of this invention, with reference numeral 1.
3 is an umbrella portion, and 3 is a stem portion extending from the center of the back surface (the middle portion is omitted in the figure). The valve body 7 is made of a conventional steel material, but the cap periphery 5 is made of a different material, such as Nimonic, and the inclined back surface of the cap periphery 5 meets the valve seat 9. It's becoming commonplace. The diameter of the joining surface 11 between the umbrella peripheral portion 5 and the valve body 7 gradually increases from the valve surface toward the back surface, and
There is a stepped portion 13 perpendicular to the axis in the middle of the joint surface 11, and the diameter becomes smaller at this portion.

With this structure, the umbrella peripheral portion 5 is supported by the stepped portion 13 and does not naturally come off on the front side of the valve. In addition, since the diameter of the joint surface 11 increases toward the back surface at a portion other than the stepped portion 13, it does not come off even to the back side of the valve.

Figure 2 shows the manufacturing method of this valve.
In manufacturing, first, the cap portion 1 of the valve body 7 is heated to a plastic state, and the cap peripheral portion 5 is fitted thereto.
When fitted in this way, there is a narrow gap 15 between them.
In order to achieve this, the diameter of the inner circumferential surface of the umbrella peripheral portion 5 is made gradually larger in advance along the direction of the back surface of the valve.
Next, using an annular mold 17 divided into several parts in the radial direction and an annular integral mold 19 outside the annular mold 17, the umbrella peripheral edge 5 is restrained from its periphery so that it does not expand. Thereafter, the periphery of the main body side cap part 1, on which a forging allowance 21 has been set in advance, is forged from both sides with a hammer or the like, and the narrow gap 15 is filled with the meat protruding from the valve body 7 side.

If necessary, after this, the valve body 7 and the umbrella peripheral portion 5 are removed.
Electric resistance welding is performed between the two using a flash butt welding method or the like.

FIG. 3 shows a manufacturing method by friction welding, in which case either one of the two, for example the valve body 7
is rotated while being pressed against the fixed umbrella peripheral edge 5, the generated frictional heat melts the stepped portion 13, and this portion is pressed into contact. Next, the narrow gap 15 is filled with the flesh of the valve body 7 by the above-described forging method shown in FIG. Note that when performing friction welding, if the vicinity of the stepped portion 13 is sufficiently melted and the narrow gap portion 15 is filled with molten metal protruding from this portion, there is no need for forging.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is an elevational view of a poppet valve partially shown in cross section, FIG. 2 is an explanatory diagram showing a method of manufacturing the poppet valve, and FIG. FIG. 2 is an explanatory diagram showing a manufacturing method. 1... Umbrella part, 3... Stem part, 5... Umbrella peripheral part, 7
... Valve body, 11 ... Joint surface, 13 ... Step part, 1
5...Narrow gap.

Claims (1)

[Scope of Claims] 1. In a poppet valve consisting of an umbrella part and a stem extending from the center of the back surface of the poppet valve, the outer circumferential edge of the umbrella part is connected to the valve body, with an annular joint surface extending from the front surface to the back surface of the umbrella part as the border. They are made of different materials, and the diameter of the joint surface gradually increases in the direction in which the stem extends, and there is a step part perpendicular to the axis in the middle of the joint surface. A poppet valve characterized in that the diameter is conversely decreasing. 2. The diameter of the outer circumferential surface of the umbrella part, where the stem extends from the center of the back surface, is larger on the front side than the back side with a step perpendicular to the axis as the boundary, and the inner diameter is larger from the front side toward the back side. The valve body has an inner circumferential surface that gradually becomes larger, and that the inner diameter conversely becomes smaller at a step part perpendicular to the axis in the middle of the inner circumferential surface, and that almost matches the outer circumferential surface of the valve body. The cap periphery formed of a different material from the main body is fitted, and then the cap of the valve body is forged while being restrained from the surroundings, thereby improving the outer circumferential surface of the valve main body. A method for manufacturing a poppet valve, characterized in that a narrow gap formed between the inner circumferential surface of the cap and the inner circumferential edge of the umbrella is filled with meat protruding from the side of the valve body. 3. The method of manufacturing a poppet valve according to claim 2, further comprising the step of electrical resistance welding the joint surface between the valve body and the peripheral edge of the umbrella. 4. The diameter of the outer circumferential surface of the umbrella part, where the stem extends from the center of the back surface, is larger on the front side than the back side with a step perpendicular to the axis as a boundary, and the inner diameter is larger from the front side toward the back side. The valve body has an inner circumferential surface that gradually becomes larger, and that the inner diameter conversely becomes smaller at a step part perpendicular to the axis in the middle of the inner circumferential surface, and that almost matches the outer circumferential surface of the valve body. The valve body and the canopy periphery made of a different material are fitted together, and then one of the valve body and the canopy periphery is rotated around the axis while applying pressure in opposite directions, and the frictional heat generated joins the valve body and the canopy periphery. A method of manufacturing a poppet valve characterized by welding the faces. 5.Furthermore, after that, the cap portion of the valve body is forged while restraining the cap peripheral edge from the periphery, thereby creating a gap between the outer circumferential surface of the valve body and the inner circumferential surface of the cap periphery. 5. The method of manufacturing a poppet valve according to claim 4, wherein the narrow gap is filled with meat protruding from the side of the valve body.