KR19980073483A - Poppet valve and manufacturing method - Google Patents

Abstract

The poppet valve is composed of a valve stem and a valve head made of light metal such as Al alloy. On the valve face of the valve head, the hard metal layer is composed of a wear resistance improving material and a light metal of the valve head formed to increase wear resistance. Thus, the durability and reliability of the poppet valve is improved.

Description

Poppet valve and manufacturing method

The present invention relates to a poppet valve and a method of manufacturing the same, and more particularly, to a poppet valve having a valve face having enhanced wear resistance.

An obstacle to the increase in the allowable rotational speed of the engine is an increase in the inertial mass due to the weight of the valve operating device. In particular, if the poppet valve is heavy, the followability of the cam according to the increase in the rotational speed is reduced, so that the output is reduced. Therefore, in order to make the valve element lightweight, the valve element or the valve head is made of light metal such as Al and Ti instead of the usual heat resistant steel.

However, the light metals described above are less thick and have high temperature characteristics as compared with the heat resistant agent. Therefore, the valve face is in contact with the valve seat, and in particular, the impact load is large, which leads to a problem of wear resistance, thereby deteriorating durability and reliability. In order to solve this problem, a valve face proposes a coating for manipulating heat resistance and a hardened heat treatment that thickly coats the operation by surface treatment.

However, a valve element made of a light metal such as Al is usually not thick, and a valve face requiring wear resistance is not obtained. In the above heat treatment, the hard coating layer is relatively thin, and it is lost in a short time, which is not practical.

An object of the present invention is to provide a poppet valve and a method for producing the same, which greatly improve wear resistance in order to cure a relatively thin surface layer of a valve face.

In the present invention, the poppet valve composed of the valve stem and the valve head increases the non-hard and metal of the valve head formed of the valve face of the valve head into a hard layer including at least the valve head made of light metal and wear resistance.

The valve face made of alloy layer increases wear resistance and reliability. The valve face formed only by the alloy layer is not affected by the thin film of the poppet valve.

In the present invention, the step of the poppet valve and the method of manufacturing the valve stem and the valve head is as follows.

The metal in the valve face of the non-metal valve head is increased by wear resistance, the wear-resistant metal property of the non-metal including the valve head of the light metal and the wear-resistant metal property is increased, and the adhesion portion of the valve face portion is heated.

It is possible to accelerate the hardening of light metals such as Al and to facilitate the manufacturing procedure of the poppet valve of the hardened valve face.

1 is a partially cutaway view of a poppet valve according to the present invention;

2 is a view showing a manufacturing step of the poppet valve.

3 is a longitudinal sectional front view of an essential part showing a method of forming a valve element by forging a ring embedded in a valve face;

Fig. 4 is a partially cutaway view showing powder fixed in an annular groove of a valve face;

Fig. 5 is a partially cutaway view showing a plurality of fixed powders of grooves of a valve face;

* Description of the symbols for the main parts of the drawings *

(1) -------------------------------- valve stem,

(2) -------------------------------- valve head,

(2a) ----------------------------- Valve face,

(3) -------------------------------- valve element,

(4), (4 ') ----------------------------- alloy layer,

(5) ------------------------------ annular groove,

(6) --------------------------------------- ring,

(7) -------------------------- Rotation Drive Support.

1 shows an embodiment of the invention, wherein the valve element 3, consisting of the valve stem 1 and the valve head 2, comprises a non-hard metal Al or Ti such as Al-Si or Ti-Al-V. It is supplied to the lower end of the valve stem 1 which consists of.

The tapered valve face 2a in the valve head 2 includes Ni, Cu, Ti, Ta, Mo (Ti removes the valve element made of Ti alloy) or wear resistance improvement made of two or more alloys thereof. The alloy layer 4 formed by the alloy Al or Ti combination of the valve element 3 to be made differs from the metal phase thin alloy layer 4, respectively.

Since the hardened alloy layer 4 is formed of the valve face 2a and it is repeatedly questioned by contact with the valve seat (not shown), abrasion resistance is greatly increased at this point, and thus durability and Reliability increases. In addition, the alloy layer 4 is formed by the valve face 2a and becomes smaller as the weight of the valve element 3 increases. This is not affected by the light weight of the valve.

The manufacturing method of a poppet valve is demonstrated. 2A to 2D show the valve process sequence.

As shown in Fig. 2A, an annular groove 5 is formed in the valve face 2a of the valve head 2 in the valve element 3 made of light metal. This annular groove 5 is formed by a forging or a mechanical process after forging. Then, as shown in Fig. 2B, the ring 6 formed of the wear resistance improving element described above is placed or fitted into the annular groove 5. The process then proceeds to the heating step shown in Fig. 2C. As a heating apparatus of this process, it is preferable to use the well-known plasma arc type powder welding apparatus P, for example, This apparatus P inclines the axis of the rotation drive support body 7 by 35 degrees, At the same time, it consists of a rotary drive support which rotates slowly in a constant direction and a torch 8 disposed with its axis vertically above. In the lower center portion of the torch 8, a plurality of holes 10 for generating an inert shield gas, such as Ar, are formed around the nozzle for generating the plasma arc 9 and around it.

In the holding ring 7a of the rotary drive support 7 in this apparatus P, the valve head 2 of the valve element 3 which holds a ring in the above process is mounted. Thereafter, the upper end of the valve stem 1 is rotatably pressed by a work holder (not shown), and the rotary drive support 7 is operated to rotate the valve element 3 in a predetermined direction. At the same time, a plasma arc 9 is generated by the torch 8 of the ring 6, heat injection of the inert shield gas 10, and the ring 6 and its retained annular grooves. The vicinity of (5) is extensively heated and melted. At this time, the torch 8 is preferably reciprocated in the left and right directions over a predetermined area. In this manner, when the valve element 3 is rotated once, as shown in FIG. 2 (D), the material of the valve element 3 is alloyed in combination with the ring 6 in the valve face 2a. A relatively hard alloy layer 4 ', which is different from the material of the valve element 3, is formed.

In this alloy layer 4 ', when the material is made of Al alloy, intermetallic compounds such as Al-Ni, Al-Cu, Al-Ti, Al-Ta, Al-Mo, or when the same Ti alloy is used Intermetallic compounds such as Ti-Ni, Ti-Cu, Ti-Ta and Ti-Mo. The valve element 3 shown in Fig. 2D shows a state in which the valve face 2a is finished in a predetermined shape by machining or the like after the completion of the step (C).

3 shows another example of a ring 6. In this example, when the valve element is formed by the mold, after inserting the ring 6 into the mold 11, the raw material (not shown) is pushed down by the punch 12 to form the valve head 2. The ring 6 is inserted into the valve face portion 2a by using the plastic deformation of the raw material at the time of making it. Therefore, as shown in 2 (A) and (B), the step of forming the annular groove 5 and the step of holding the ring 6 can be omitted, thereby reducing the number of steps. .

FIG. 4 fills the annular groove 5 formed of the valve element 3 with powder 13 made of the above-described wear-resistant improving element instead of the ring 6. The powder 13 may be in the form of a powder, but in consideration of falling during the workpiece conveyance, the powder 13 is preferably a compressed powder. Moreover, when this powder is used, dissolution of the powder 13 is accelerated and the heating time is shortened. In particular, it is suitable as a valve element made of Al alloy having a low melting point.

5, the groove | channel 14 is formed in the valve face 2a, and the powder 13 is put in this groove | channel 14. As shown in FIG. In this example, since a part of the raw material is exposed, the raw material is also heated and melted effectively, and alloying is performed quickly.

The present invention is not limited to the above embodiment, and, for example, except that the valve element 3 is made of Al alloy or Ti alloy, as described above, the upper portion of the valve stem 1 is usually made of heat resistant steel. In addition, it is also suitable as a stem weld type poppet valve made of Al alloy or Ti alloy as described above under the valve stem 1 including the valve head 2.

Since the valve face 2a is a tapered surface which is enlarged downward, the valve face 2a may be heated and melted by simply placing the ring 6 unless the annular groove 5 is formed. At this time, the cross-sectional shape of the ring 6 can also be made into the flat shape in which the lower surface is in close contact with the valve face 2a.

By holding the powder 13 in the valve face part 2a, it can adhere | attach it with a suitable binder without the annular groove 5 and the groove | channel 14.

As the heating means of the valve face 2a, instead of the plasma arc, high-density energy such as a laser or an electron beam may be used.

Modifications and variations in the art relating to the above examples of the invention are possible by those skilled in the art without departing from the scope of the claims.

Claims (13)

In the valve stem (1), the valve head (2), and the valve head (2) made of at least light metal, the valve face (2a) in the valve head (2) has a material for improving wear resistance and a hard alloy. Poppet valve, characterized in that consisting of a thick alloy layer. The poppet valve according to claim 1, wherein the light metal is made of Al alloy or Ti alloy. The poppet valve according to claim 1, wherein the wear resistance improving element is made of Ni, Cu, Ti, Ta, Mo, or an alloy composed of two or more elements. In a poppet valve composed of the valve stem 1 and the valve head 2, an element for improving wear resistance is brought into close contact with the valve face 2a of the valve head 2 formed of a light metal, and the welded portion of the valve face 2a is heated. And an alloy layer comprising a hard alloy of the valve head and an element for improving wear resistance. The method of manufacturing a poppet valve according to claim 4, wherein the light metal is made of Al alloy or Ti alloy. The method for producing a poppet valve according to claim 4, wherein the wear resistance improving element comprises Ni, Cu, Ti, Ta, MO, or two kinds of alloys or more elements. The method of manufacturing a poppet valve according to claim 4, wherein the wear resistance improving element forms a ring (6) in close contact with the valve face (2a). 5. A method for producing a poppet valve according to claim 4, wherein the wear resistance improving element comprises compressed powder (13) or powder (13) in close contact with the valve face (2a). The method of manufacturing a poppet valve according to claim 4, wherein the poppet valve is placed in a valve face (2a) having an element for improving wear resistance. The method of manufacturing a poppet valve according to claim 4, wherein the groove (14) formed in the valve face (2a) has a groove (14) for improving wear resistance. The method of manufacturing a poppet valve according to claim 4, wherein an element for improving wear resistance is inserted into the plurality of grooves (14). The method of manufacturing a poppet valve according to claim 4, wherein a laser, a plasma arc, or an electron beam, such as high density energy, is used as a heat means for the valve face. 5. The method of manufacturing a poppet valve according to claim 4, wherein the valve face (2a) is heated to weld a gas body that is an inert shield gas.