JP4161757B2 - Manufacturing method of intake / exhaust valve for engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for manufacturing an intake / exhaust valve for an engine and a structure of a chuck used therefor, and more particularly, to a method for manufacturing an intake / exhaust valve for an engine in which a build-up layer of a dissimilar metal is formed on a valve face portion that is most important in function. And a chuck structure suitable for use in the build-up processing.
[0002]
[Prior art]
For the purpose of improving engine performance and reducing the weight of the engine, a light alloy material represented by, for example, an aluminum alloy is being adopted as an intake / exhaust valve for the engine. On the other hand, light alloy materials are inferior in wear resistance particularly at high temperatures as compared with iron-based alloy materials that have been the mainstream until now. In order to impart wear, a build-up layer of a dissimilar metal material such as a copper alloy is formed using a high-density heat source such as a laser.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-257034 (FIGS. 1 and 2)
[0004]
[Problems to be solved by the invention]
The supply / exhaust valve in which the build-up layer as described above is formed is generally finished to a shape close to the shape of the final product by the build-up processing, and thus particularly includes the valve face portion. The umbrella is thin and has a very small heat capacity. Therefore, the umbrella part is heated by heat input at the time of build-up processing, and secondary defects such as cracking of the build-up layer occur due to melting of the base material and dilution of the build-up layer by the base material. It's easy to do.
[0005]
In addition, when the heat input is adjusted so as not to cause melting damage and dilution of the base material, it takes a long time for the build-up processing, and the productivity is inevitably lowered especially in mass production. It is not preferable.
[0006]
The present invention has been made paying attention to such problems, and in particular, by increasing the heat capacity of the supply / exhaust valve at the time of build-up processing, it is possible to prevent the occurrence of defects such as erosion, so that the build-up processing can be performed quickly and The present invention provides a manufacturing method that can be performed stably.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is a method of manufacturing an air supply / exhaust valve for an engine in which a build-up layer of a dissimilar metal is formed on the valve face portion, and the valve face portion is removed when preforming the valve rough material. A first step of forming a shape in which a surplus portion is added to the back side of the umbrella portion and the valve head portion side, a second step of applying a build-up process to the valve face portion, and a finishing process after the build-up process third and steps, a Te-containing Ndei, when preforming the valve coarse material in the first step, the back side and the valve head portion of the umbrella portion excluding the valve face portion to remove the excess thickness portion is subjected Each side has a frustoconical shape by adding a surplus portion along the inclination of the valve face portion, and a cylindrical surplus portion is added continuously to the surplus portion on the valve head side. It is characterized by molding .
[0008]
In this case, the material of the valve rough material is, for example, an aluminum-based powder metallurgy alloy, and the columnar surplus portion added to the valve head portion side is equivalent to the valve head portion as described in claim 2. as also of that of a large diameter slightly even than that.
[0009]
Therefore, in the invention described in claim 1, since the surplus part is attached to the rough valve material at the stage of the build-up processing, the heat capacity as the rough valve material is increased only by the surplus part. At the same time, since the vicinity of the valve face is sufficiently thickened, it is possible to prevent the occurrence of melting damage and cracks associated with the build-up processing. And the surplus part unnecessary in terms of product function is cut and removed by machining or the like only after the build-up process.
[0010]
On top of that, the invention described in claim 4, the valve coarse material gripped by Chi jack when subjected to padding processing while rotating the axis thereof as the center of rotation, the valve head of the valve coarse material by the chuck jaws characterized by chucking out径把lifting scheme part cylindrical outer peripheral surface of the excess thickness portion of the added cylindrically side and substantially the entire end face as gripping surfaces.
[0011]
In this case, the chuck claw is made of a material having excellent thermal conductivity such as copper or aluminum, and the chuck claw is cooled so that a cooling medium for forced cooling flows through the chuck claw. It is desirable that a passage is formed.
[0012]
Therefore, in the invention according to claim 4, since the chuck claw having a large area and excellent heat conductivity is in contact with the rough valve material at the time of overlaying, further temperature of the rough valve material at the time of overlay processing is reached. It will be possible to expect a rise-inhibiting effect.
[0013]
【The invention's effect】
According to the first aspect of the present invention, since the heat capacity increases only in the surplus portion during the build-up process, it is possible to prevent the occurrence of problems such as melting damage and cracks by suppressing the temperature rise of the valve crude material. In addition, the overlay processing can be performed quickly and stably, and the productivity at the time of mass production is improved.
[0014]
According to the invention described in claim 4, since the contact area between the chuck and the valve rough material that grips the valve rough material during the build-up processing is remarkably increased, The temperature rise can be further suppressed, and in addition to the same effect as that of the first aspect, it is possible to improve the material yield by reducing the amount of surplus part as necessary, and thus contributing to the reduction of the production cost. There are advantages that can be done.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
1 to 4 are views showing a preferred embodiment of the present invention. In particular, FIG. 1 shows an outline of a manufacturing process of an air supply / exhaust valve, FIG. 2 shows a state of a single valve rough material, and FIG. The principal part enlarged view in each is shown.
[0016]
In the preforming step of FIG. 1A, the valve crude material 2 is formed using, for example, an aluminum-based powder metallurgy alloy, and more specifically, an aluminum-based sintered round bar W is used as a material. The valve rough material 2 is formed by machining or forging. The shape of the original air supply / exhaust valve (hereinafter simply referred to as a valve) 1 includes an umbrella portion 4 including a valve face portion 3, a valve head portion (umbrella front portion) 5, and a valve stem portion as shown in FIG. However, in the present embodiment, it is formed into a shape in which surplus portions (recess portions) 7, 8 and 9 are positively added to portions other than the valve face 3 portion.
[0017]
More specifically, as shown in FIG. 2, an extra portion 7 is added to the back surface (back surface) side along the inclination of the valve face portion 3 while leaving a width corresponding to the valve face portion 3 of the umbrella portion 4. At the same time, a surplus portion 8 is similarly added to the valve head portion (umbrella front portion) 5 along the inclination of the valve face portion 3, and the surplus portion 8 is continuously connected to the surplus portion 8. A very thick solid cylindrical or columnar surplus portion 9 having the same diameter is integrally added. In FIG. 2, the surplus portions 7, 8, and 9 set in the respective parts are shown in different cross sections for easy understanding. However, the surplus portions 7, 8, and 9 are also the same as the valve rough material 2. It is molded integrally with the material.
[0018]
Here, the reason why the extra-thick surplus portion 9 is set continuously to the surplus portion 8 is that the valve head portion 5 side is more likely to be melted or diluted due to insufficient heat capacity. Although the maximum diameter of the part 8 (= the diameter of the surplus part 9) varies depending on the size of the valve 1 itself, for example, the maximum diameter of the surplus part 8 is set to be about 4 mm larger than the maximum diameter of the umbrella part 4 and at the same time The thickness H of the meat part 9 is set to about 10 to 30 mm.
[0019]
In the subsequent build-up process of FIG. 1B, as shown in FIG. 3, the rough valve material 2 inclined by a predetermined angle is gripped by the chuck 10 using the surplus portion 9 as a grip portion. As it is known, a build-up layer 12 is formed by irradiating a laser beam 11 while supplying, for example, copper alloy powder, which is a different metal material, to the valve face portion 3.
[0020]
As the copper alloy powder that is a build-up material, for example, “MCuNi2” manufactured by Mitsui Mining & Smelting Co., Ltd., which is generally marketed, is used, and the supply amount onto the valve face portion 3 is about 50 to 70 g / min. . Further, a CO ₂ laser is used as a laser that is a heat source, the spot size of the laser beam 11 on the bulb face portion 3 is an elliptical shape of about 2 × 4 mm, and the laser output at the processing point is 4.0. ˜4.8 kW, and processing speed is about 1.2 m / min.
[0021]
Further, as the material of the chuck 10 that holds the rough valve material 2, for example, copper or aluminum-based A5056 material is used as a material having excellent heat conductivity, as is apparent from FIGS. 3 and 4. Each chuck claw 10a of the chuck 10 is in contact with substantially the entire cylindrical outer peripheral surface and end surface of the surplus portion 9 in the gripped state of the valve rough material 2, that is, substantially the entire cylindrical outer peripheral surface and end surface of the surplus portion 9. Is set so as to chuck the valve rough material 2 with the gripping surface as a gripping surface. In each chuck claw 10a, a water jacket 13 is formed as a cooling passage for forced cooling with cooling water as a cooling medium, and the cooling water is circulated between cooling water supply sources (not shown).
[0022]
Accordingly, during the build-up process, the heat capacity is dramatically increased by the extra portions 7, 8, and 9 added to the valve rough material 2, so that the temperature rise in the vicinity of the valve face portion 3 is increased. It is suppressed. At the same time, since almost the entire surplus portion 9 is in contact with the chuck claws 10a having excellent heat conductivity, and each chuck claw 10a is forcibly cooled with cooling water, the temperature rise of the valve rough material 2 is suppressed. As a result, the cooling effect is further improved. As a result, the occurrence of cracks in the vicinity of the valve face portion 3 and cracks due to dilution of the base material can be prevented.
[0023]
In this way, when the build-up processing is finished, the build-up layer 12 is subjected to cutting machining in the finishing process shown in FIG. 1C, which is the next step, and a part of the build-up layer 12 is cut off to be predetermined. Finish in shape. At the same time, the surplus portions 7, 8, 9 unnecessary for the valve function are removed by machining.
[0024]
As a result of the present inventor performing the build-up processing of the 20 valves 1, 1... By the above method, it has been found that no defects such as melting or cracking occur. On the other hand, as a result of depositing 10 valves 1, 1... Under the same conditions without adding surplus portions 7, 8, 9, no melt damage occurred, but all valves In FIG. 3, cracks were observed due to dilution of the base material due to excessive heat input at the end portion of the buildup layer 12 (the portion where the buildup end portion and the buildup end portion overlap).
[0025]
Moreover, since the cooling promotion effect can be expected by forcibly cooling the chuck claw 10a with the water jacket 13 formed on each chuck claw 10a, the volume of the surplus portions 7, 8, 9 can be reduced as necessary. In this case, the production cost can be reduced by improving the material yield.
[Brief description of the drawings]
FIG. 1 is a schematic process explanatory view showing a preferred embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional explanatory view of the valve crude material in FIG.
FIG. 3 is an enlarged cross-sectional explanatory view at the time of build-up processing using the valve coarse material of FIG. 2;
4 is an explanatory plan view of the chuck of FIG. 3; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Supply / exhaust valve 2 ... Valve rough material 3 ... Valve face part 4 ... Umbrella part 5 ... Valve head part 7,8,9 ... Surplus part 10 ... Chuck 10a ... Chuck claw 11 ... Laser beam 12 ... Overlay layer 13 ... Water jacket (cooling passage)

Claims (5)

A method of manufacturing an intake / exhaust valve for an engine in which a build-up layer of a different metal is formed on a valve face part,
When preforming the valve coarse material, a first step of forming on the back side and the shape obtained by adding each excess thickness portion to the valve head portion of the umbrella portion excluding the valve face portion,
A second step of performing padding processing to the valve face portion,
A third step of finishing after the build-up processing to remove the surplus portion,
The Te including Ndei,
When preforming the valve rough material in the first step, an extra portion is added along the inclination of the valve face portion on the back side and the valve head portion side of the umbrella portion excluding the valve face portion. A method for manufacturing an air supply / exhaust valve for an engine, which is formed into a trapezoidal shape and further formed into a shape in which a columnar surplus portion is integrally added continuously to a surplus portion on the valve head side . EXH valve engine according to claim 1, wherein the excess thickness portion cylindrical to be added to the valve head portion is of greater diameter slightly larger than equal to or its valve head portion Manufacturing method.   The method of manufacturing an air supply / exhaust valve for an engine according to claim 1 or 2, wherein the finishing process includes finishing machining of the valve face part and cutting process of the surplus part. Of the columnar surplus portion added to the valve head side of the valve rough material by the chuck claw when the rough valve material gripped by the chuck is rotated while rotating about its axis as the center of rotation. The method for manufacturing an intake / exhaust valve for an engine according to any one of claims 1 to 3 , wherein chucking is performed by an outer diameter gripping method using substantially the entire outer peripheral surface and end surface of the cylinder as a gripping surface. 5. The intake / exhaust for an engine according to claim 4, wherein a cooling passage through which a cooling medium flows is formed in the chuck claw, and the chuck claw is subjected to build-up processing while forcibly cooling the chuck claw with cooling water. Manufacturing method of valve .

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