JP2000045730A - Valve element for poppet valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a poppet valve applied to an engine and a compresser as a suction and a discharge valve by press-forming instead of a usual forged part. SOLUTION: A cone-shaped seating face 21a provided on a peripheral edge; a hollow stem 22; and a bevel part 21 having an about cone-shaped skirt part 21 between the two parts 21a, 22 are unitedly formed by the plastic forming with a steel plate, and the stem is also hollowly formed for reducing the inertial weight of a valve system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a poppet valve suitable for an engine.

[0002]

2. Description of the Related Art Conventionally, a poppet valve used in a piston crank type compressor such as an engine or a compressor has an air passage 12 leading to a compression chamber 11 as shown in FIG.
And a valve body 20 cooperating with the valve seat 13. The valve body 20 has an umbrella portion 21 seated on the valve seat 13 and a stem 22 connected to the umbrella portion 21. An end of the stem 22 opposite to the umbrella portion 21 is provided with a valve cotter 14 and a retainer 15. An engagement groove 23 for supporting the valve spring 17 is formed. The valve body 20 is generally made by forging a high-tensile alloy steel as a whole, but in the case of an engine, different materials are used on the umbrella side and the shaft side to improve heat resistance and reduce weight. Sometimes. Also,
In special cases, sodium may be sealed with the shaft side hollow for heat resistance and weight reduction (Automotive Technology Handbook, 2nd edition, 73rd edition, published by the Japan Society of Automotive Engineers of Japan).
page).

[0003]

Since the valve element used in the compressor reciprocates at a high speed, the weight of the valve element is largely reduced by reducing the size and weight of the entire valve train such as a valve spring and a cam follower. In order to contribute, research on weight reduction, such as conventionally used materials, structures and shapes, processing methods, and heat treatments, is being conducted in depth. However, there is no limit to the weight reduction of the valve train, and technical development for weight reduction is always required.

[0004]

An object of the present invention is to integrate a conical seating surface provided on a peripheral edge, a hollow stem, and an umbrella portion having a substantially conical skirt portion therebetween by plastic working of a steel plate. It can be solved by forming in a proper manner. Here, it is preferable that the umbrella portion and the hollow stem are integrally formed by plastic working of a steel plate. More preferably, the end of the hollow stem on the umbrella side is closed by a lid member. The stem may be a hollow material with a bottom that closes the umbrella-side end, and the opening formed on the valve spring side may be closed by a lid member having a cotter groove. Further, the opening end of the umbrella may be covered with a closing lid.

[0005]

The umbrella portion of the valve body is made thin from the inside of the seating portion to the skirt, and the inner surface thereof is largely lightened. Further, the portion from the seating surface forming the umbrella portion to the stem via the skirt portion is made of a plate material, but has a high rigidity because it is all formed of a curved surface. [Claim 2] Not only the umbrella portion, but also the valve body is continuously hollowed from the umbrella portion to the stem, and its shape is formed by plastic working. [Claim 3] Although the stem is made hollow, since the end is closed by the lid member, there is no connection with the compression chamber, and the volume in the compression chamber is reduced. [Claim 4] A bottom formed at one end of the stem is used as the lid member. Further, since the cotter groove is formed in the shaft head member, the diameter of the stem can be further reduced. [Claim 5] The umbrella section is completely hollow, reducing the volume in the compression chamber.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows a poppet valve 10 according to the present invention.
1 shows an essential part of a piston crank type compressor 16 such as an engine using a compressor or a compressor. The compressor 16 has a combustion chamber serving as a compression chamber 11 formed on the lower surface of the cylinder head. The valve element 20 is provided in each of an intake path and an exhaust path as the ventilation path 12. Reference numeral 17 denotes a valve spring, and the valve body 20 is connected to the valve body 20 via the retainer 15 and the cotter 14.
Always bias in the closing direction. Reference numeral 18a denotes a valve operating cam forming a valve operating system, 18b denotes a rocker arm, and 18c denotes a hydraulic lash adjuster serving as a fulcrum of the rocker arm 18b.

As shown in FIG. 2, the valve body 20 is formed by press-forming a steel plate to form an umbrella portion 21 including a seating surface 21a, a stem 2
2 and the engaging groove 23 are integrally formed. That is, one steel plate is deep drawn to form a stem 22, and then a wrinkle suppressing portion (not shown) in the previous step is press-formed to form a frusto-conical seating surface 21a and a seating surface 21a. Smooth skirt 21 connected to 22
b to form an umbrella 21 and a stem 22
An engagement groove 23 is formed plastically by spinning the outer circumference at the other end of the. It goes without saying that the sliding surface on the outer periphery of the stem 22 and the seating surface 21a are polished as in the conventional case. By molding the valve body 20 into such a shape, the valve body 20 can be easily manufactured by plastic working, the valve body 20 can be reduced in weight, the valve spring 17 can be made thinner and lighter, and the rocker arm can be formed. 18
Parts of the valve train such as b can be reduced in weight.

FIG. 3 shows another embodiment of the valve body 20. In this case, by closing the lower end of the stem 22 with the lid member 24, the compressed air in the compression chamber 11 is prevented from entering the inner surface of the stem 22, and the compression pressure in the compression chamber 11 is prevented from lowering. In this embodiment, the portion of the stem 22 close to the skirt portion 21b is formed slightly thicker as shown by B in the figure, the cover member 24 is press-fitted into this portion, and the hardening point is 800 ° C. or higher. Brazed with wax. This avoids stress concentration at the continuous portion between the stem 22 and the skirt portion 21b, and ensures high strength.

The means for closing the lower end of the stem 22 includes:
As shown in FIG. 4, the umbrella 21 is separate from the stem 22,
It is also effective to close the umbrella unit 21. In this case, as shown by C in the figure, the opening forming the lower end of the stem 22 is narrowed to have a small diameter, and that portion is formed into the skirt 2 of the umbrella 21.
It is fitted to the annular portion 21c following 1b and brazed in the same manner as described above. Note that the umbrella portion 21 is press-formed independently, and the end plate 25 is applied to a large-diameter opening forming the umbrella portion 21, and closed by metallurgy by welding or brazing or plastically by caulking. is there. In this case, the end plate 25 receiving a high pressure is reinforced by a rib 25b provided on the back surface, or a small-diameter vent hole 25 is formed in the end plate 25.
Providing a to reduce the pressure difference between the front and back is effective in increasing the durability. Further, in the case of an engine having a high gas pressure, it is preferable that the umbrella portion 21 is formed by casting a stellite or other heat-resistant metal and performing necessary machining.

The stem 22 is formed by plastic working.
Since one end is opened, the closed side is configured as the rocker arm 18b side in the embodiments of FIGS. 2 to 4, but this configuration is not essential, and as shown in FIG.
The opening side may be configured as the rocker arm 18b side. In this case, the side of the stem 22 where the bottom plate 22a is located is brazed to the umbrella portion 21. As a result, the bottom plate 22a is used as a substitute for the lid member 24. A shaft head member 26 having a high-precision engagement groove 23 machined is fitted into the open end of the stem 22 and brazed as described above.
In this way, a poppet valve element 20 plastically molded with a minimum number of parts is obtained.

[0011]

According to the first aspect of the present invention, the seating surface and the skirt portion forming the umbrella portion are integrally formed by plastically processing a steel plate, and they are formed by continuous curved surfaces. Therefore, the umbrella portion of the valve body can be made lightweight and highly rigid. In addition, by connecting this to the stem, a lightweight and highly rigid valve element can be obtained. Claim 2
According to the invention, since the umbrella portion and the stem forming the valve body are integrally manufactured by press-forming a steel plate, the manufacturing is easier than the conventional forged poppet valve, and the valve is The body can be made lightweight. As a result, the inertial mass of the valve train can be significantly reduced, and the upper limit of the operating speed of the reciprocating engine can be greatly increased. According to the third aspect of the present invention, since the inside of the hollow stem and the compression chamber are shut off by the lid member, even if a lightweight stem is hollowed out, the compression ratio does not decrease. According to the fourth aspect of the present invention, since the stem itself is used as a lid member that shuts off the inner surface of the hollow stem and the compression chamber, no special parts are required, and the structure of the valve body is simplified. Further, since an opening is left at the shaft end of the stem, there is no particular difficulty in manufacturing the stem, and the opening is used for mounting the shaft head member, thereby eliminating waste. According to the fifth aspect of the invention, although the umbrella portion has a form in which the seating surface and the skirt portion are press-formed, the opening is closed by the closing lid, and the problem of lowering the compression ratio in the compression chamber is eliminated. .

[Brief description of the drawings]

FIG. 1 is a sectional view of a compressor showing one embodiment of the present invention.

FIG. 2 is an axial longitudinal sectional view showing a poppet valve, which is a main part of the poppet valve.

FIG. 3 is a longitudinal sectional view showing a modification and corresponding to FIG. 2;

FIG. 4 is a longitudinal sectional view corresponding to FIG. 2 and showing a modified example thereof.

FIG. 5 is a longitudinal sectional view corresponding to FIG. 2 and showing a modified example thereof.

FIG. 6 is a longitudinal sectional view showing a conventional compressor and corresponding to FIG.

[Explanation of symbols]

 Reference Signs List 10 poppet valve 11 compression chamber 12 air passage 13 valve seat 14 valve cotter 15 retainer 16 compressor 17 valve spring 18a valve actuation cam 18b rocker arm 18c hydraulic lash adjuster 20 valve body 21 umbrella 21a seating surface 21b skirt 22 stem 22a Bottom plate 23 Engagement groove 24 Lid member 25 End plate 25a Vent hole 25b Rib 26 Shaft head member

Claims (5)

[Claims] 1. A poppet valve formed by integrally forming a conical seating surface provided on a peripheral edge, a hollow stem, and an umbrella having a substantially conical skirt portion therebetween by plastic working of a steel plate. Valve body. 2. The poppet valve body according to claim 1, wherein said umbrella portion and said hollow stem are integrally formed by plastic working of a steel plate. 3. The valve body of a poppet valve according to claim 2, wherein the umbrella-side end of the hollow stem is closed by a lid member. 4. The poppet valve according to claim 2, wherein the stem is a hollow material having a bottom whose end on the umbrella portion side is closed, and an opening formed on the other side is closed by a shaft head member having a cotter groove. Valve body. 5. The valve body of a poppet valve according to claim 1, wherein an opening end of the umbrella portion is covered with a closing lid.