JPH02196118A - Manufacture of valve spring seat made of aluminum alloy - Google Patents

Abstract

PURPOSE:To manufacture such a product that is lighter in weight and excellent in abrasion resistance simply and inexpensively by manufacturing a powder compact with plural kinds of aluminum alloy powder different in Si content, and forging this power compact. CONSTITUTION:At the time of manufacturing, first second aluminum alloy powder 12 containing Si of less than 16wt.% in a lower part is charged in a cavity 10 being formed by a compression mold 7, a core mold 8 and a sleeve mold 9 of a drag 6 in a powder molding unit and first aluminum alloy powder 11 containing Si of more than 20wt.% in the remaining upper part, respectively. After a cope 13 is lowered, the sleeve mold 9 is operated as an ejector, forming a blank 14. Next, a lower part 12A of this blank 14 is inserted into a recess of a drag 15 in a forging unit, and then a cope is lowered, forging this blank 14 into being formed. Afterward, this forged part is machined, thus an aluminum alloy-made valve spring seat is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a valve spring seat used in a valve mechanism of an engine.

[Prior art]

As shown in Fig. 11, in an engine valve mechanism, a valve stem 100 is attached to the output section of a cam or rocker arm in order to move valves such as intake valves and exhaust valves integrally with the output section of the cam or rocker arm. A valve spring 101 that elastically biases the valve spring 101 and a valve spring seat 103 that receives the upper end of the pulp spring 101 and transmits the spring force to the valve stem 100 via the rotor 102 are provided.

The valve spring seat 103 has been manufactured by forging using a steel material with excellent wear resistance.

By the way, since the above-mentioned valves are driven up and down at high speed, recently the performance of the valve mechanism has been improved by reducing the weight of the valve spring seat 103 and its inertial mass, thereby increasing the engine's maximum rotation speed, output, and dynamic performance. Research is underway to improve the power requirements of valve mechanisms.

Therefore, in order to reduce weight, the above valve spring seat was replaced with Aj! It has also been proposed to manufacture it from -3i series aluminum alloy.

For example, as shown in FIGS. 12 to 14, a cylindrical billet 110 is manufactured by press-molding silicon-containing aluminum alloy powder produced by rapid solidification in a heated state. Set the billet 110 in the recesses 111a of the forging dies 111 and 112 (Fig. 12).
Figure 13.
(Fig. 14), then the forged product 110A is cut to produce a valve spring seat.

On the other hand, for example, Japanese Utility Model Application Publication No. 63-24311 discloses a main body made of a high-strength aluminum alloy and a member made of a high-silicon aluminum alloy in which 2 to 10% by volume of hard particles are dispersed on the contact surface that contacts the valve spring. A combined two-layer valve spring seat is disclosed.

The high-strength aluminum alloy main body of the valve spring seat of the above publication is made of an aluminum alloy containing 9 to 15% by weight of St, and the high-silicon aluminum alloy member has a St content of 11 to 20% by weight.
It is made by dispersing hard silicon particles crystallized during extrusion molding into an aluminum alloy containing % by weight of St.

When manufacturing this valve spring seat, a cylindrical billet body for the valve spring seat body is produced by molding low-silicon aluminum alloy powder, and then this billet body is placed in a mold of a powder molding machine. After filling the periphery with high-silicon aluminum alloy powder, a cylindrical billet is produced by pressure forming, and this billet is processed into a round bar material by extrusion molding, and this round bar material is cut into a predetermined length. A forged material (blank) is produced by cutting into pieces, and then the forged material is forged into the shape of a valve spring seat.

Therefore, the valve spring abutting portion of this valve spring seat is made of a high-silicon aluminum alloy in which crystallized hard silicon particles are dispersed.

[Problem to be solved by the invention]

The former method for manufacturing a valve spring seat (No. 12)
14), an aluminum alloy valve spring seat can be manufactured using relatively simple equipment and a small number of steps. When the silicon content of the aluminum alloy is 16% by weight or less, it has sufficient ductility and can be well forged. However, aluminum alloys with a silicon content of 16% by weight or less have insufficient wear resistance and fatigue resistance, making it impossible to obtain a valve spring seat that can withstand practical use.
The above is necessary.

However, when the silicon content exceeds 20% by weight, the steel becomes hard and the ductility significantly decreases, resulting in problems such as cranking and under-walled portions when forged. Therefore, it must be manufactured by cutting the aluminum alloy material, or it must be formed in two forging steps, but these methods increase the number of steps and make the manufacturing cost extremely high. There are problems such as storage.

On the other hand, the method for manufacturing a valve spring seat described in the above-mentioned publication requires four steps: two powder molding steps, an extrusion molding step, and a forging molding step, so at least four types of expensive equipment are required as the manufacturing equipment. In addition, there is a problem that the production cost of the valve spring seat is extremely high.

An object of the present invention is to provide a manufacturing method for manufacturing a valve spring seat whose valve spring contact portion is made of an Affi-Si aluminum alloy and has excellent wear resistance using fewer steps and a simple device.

[Means to solve the problem]

The method for manufacturing an aluminum alloy valve spring seat according to the present invention involves forming a first aluminum alloy powder containing 20% by weight or more of Si and a second aluminum alloy powder containing 16% by weight or less of Si. A cylindrical powder compact is manufactured in which one end in the axial direction is made of the first aluminum alloy powder and the remaining part is made of the second aluminum alloy powder, and the remaining part of the powder compact is inserted into the recess of the forging die. A valve spring seat made of an aluminum alloy, characterized in that the powder compact is forged into the shape of a valve spring seat to produce a valve spring seat whose valve spring contact portion is made of an aluminum alloy containing 20% by weight or more of Si. It manufactures.

[Effect]

In the method for manufacturing an aluminum alloy valve spring seat according to the present invention, when molding a powder compact, a high-silicon first aluminum alloy powder containing 20% by weight or more of silicon and 16% by weight of silicon are placed in the mold. By pressing and molding the low silicon-containing second aluminum alloy powder in a layered manner under heating, one end is made of the first aluminum alloy powder and the remaining part is made of the second aluminum alloy powder. A powder compact made of powder can be easily manufactured.

During forging, when the remaining part of the powder compact is inserted into the recess of the forging mold and forged, one end of the powder compact made of the high-silicon first aluminum alloy powder becomes
It is pressed by a pair of forging dies and flattened while extending in the radial direction, but since it only flows in one direction in the radial direction and the flow distance is not too long, it can be formed well even if it has poor ductility. . The remaining part of the powder compact consisting of the low-silicon secondary aluminum alloy powder flows in a complicated manner in and around the recess of the forging die, but because it is low in silicon, it is relatively soft and ductile. Well molded. In particular, the flow of the low-silicon aluminum alloy supplies sufficient alloy material to the high-silicon aluminum alloy, thereby preventing cracks and underfilling.

The lower end surface of the part that extends in the radial direction and is formed into a brim shape becomes the valve spring contact part, and since this contact part is made of a high-silicon aluminum alloy, it has excellent wear resistance and fatigue resistance. There is.

In order to ensure wear resistance and fatigue resistance of the valve spring contact portion, it is necessary that the first aluminum alloy powder contains 20% by weight or more of St. In addition, in order to ensure ductility during forging, the second aluminum alloy powder was
It is necessary to contain 6% by weight or less of Si.

〔Effect of the invention〕

According to the method for manufacturing an aluminum alloy valve spring seat according to the present invention, as described above, a high-silicon first aluminum alloy powder containing 20% by weight or more of St and 16% by weight or less of Si are used. Low silicon second
A lightweight valve spring seat made of aluminum alloy can be manufactured easily and inexpensively by a simple method of manufacturing a powder compact using aluminum alloy powder and forging the powder compact. The valve spring contact part is made of high-silicon aluminum alloy, so it has excellent wear resistance.

Furthermore, by appropriately limiting the area to which the high-silicon aluminum alloy is applied, it is possible to reliably prevent cracks and underfilling during forging.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

This embodiment is a valve spring seat 4 that receives and stops a valve spring 3 of a valve mechanism 2 that drives an intake valve 1 and an exhaust valve of an engine as shown in FIG. -S
This is an example in which the present invention is applied to a manufacturing method for manufacturing a valve spring seat 4 made of an i-based aluminum alloy.

In the first step, 20% by weight or more of Si is
A first aluminum alloy powder containing Si (hereinafter referred to as first aluminum alloy powder) and a second aluminum alloy powder containing 16% by weight or less of Si (hereinafter referred to as second aluminum alloy powder) are manufactured.

When manufacturing the above-mentioned first aluminum alloy powder, the first aluminum alloy powder in Table 1
The aluminum alloy base material is melted, and the molten metal is injected into an Ar gas atmosphere from a nozzle and rapidly solidified at a cooling rate of 104°C/sec. Metshu at 70%〉25
The powder is classified so that 30% of the aluminum alloy powder is 0.0%, and then the powders with different meshes are mixed at a predetermined ratio to obtain a first aluminum alloy powder.

When manufacturing the above-mentioned second aluminum alloy powder, the second aluminum alloy powder in Table 1
The base material is aluminum alloy, and the rest is the same as above.

However, since the manufacturing process of the first and second aluminum alloy powders is the same as the existing well-known process, other explanations will be omitted.

In the second step, the first aluminum alloy powder and the second aluminum alloy powder are press-formed to form a cylindrical blank (forged material), the upper end of which is made of the first aluminum alloy powder, and the remaining part is made of the first aluminum alloy powder. 2 A blank made of aluminum alloy powder is manufactured as follows.

That is, as shown in FIG. 2, the solid mold 7, core mold 8, and sleeve mold 9 of the lower mold 6 of the powder molding device (vacuum hot press)
About 273 of the lower part in the cylindrical cavity 10 formed by
The second aluminum alloy powder 12 is filled in the second aluminum alloy powder 12, the first aluminum alloy powder 11 is filled in the remaining part of the cavity 10 (the upper part 173), and then the first and second aluminum alloy powders 11 and 12 are filled. is heated to about 350°C, the upper mold 13 is driven downward into the cavity 10 as shown in Fig. 3, and the powder is molded by holding the powder under a pressure of about 2000 kg/cd for about 1.0 hour. Next, the sleeve mold 9 is ejected to obtain a blank 14 made of a powder compact as shown in FIG.

Approximately 1/3 upper portion 11A of the blank 14 is made of high silicon first aluminum alloy powder 11, and the blank 14
The lower portion 12A of about 273 is comprised of the low silicon second aluminum alloy powder 12.

In the third step, the blank 14 is forged as follows to produce a valve spring seat forged product 4A.

That is, as shown in FIG.
With the lower part 12A of the blank 14 inserted into the blank 14, the upper die 16 is driven downward and the blank 14 is forged with the upper die 16 and the lower die 15 as shown in FIGS. 6 and 7. .

During this forging, the lower part 1 of the blank 14 is about 273.
Since 2A is formed of the second aluminum alloy powder 12 with low silicon content, it is relatively soft (and has high ductility, so the alloy material flows easily, and it also flows toward the first aluminum alloy powder 11, which is hard and has poor ductility). I will do it.

The upper 1/3 portion 11A of the blank 14 is made of the first aluminum alloy powder 11 with high silicon content, and is hard and has poor ductility, but this portion only needs to flow in one radial direction. Since the distance between the aluminum alloy and the aluminum alloy powder 11 is not too large and the alloy material of the first aluminum alloy powder 11 is replenished from below, the aluminum alloy forged product 4A is free from defects (cranks and missing parts) throughout the forged product 4A. . and a valve spring contact portion 4 that the valve spring 3 contacts.
a is a part 4 formed into a brim shape by the upper mold 16 and the lower mold 15.
This brim-shaped portion 4b is formed from a high-silicon first aluminum alloy forged with high-silicon first aluminum alloy powder 11, so the valve spring contact portion 4a is wear-resistant. It has excellent durability and fatigue resistance.

In the fourth step, the forged product 4A is machined to obtain an aluminum alloy valve spring seat 4 as shown in FIG. 8.

FIG. 9 shows how the valve spring seat 4 is attached to the valve train 2.
The valve spring 3 made of a compression coil spring is shown in a state where it is assembled into a valve spring seat 4 and a valve spring 3 made of a compression coil spring.
The spring force is transmitted from the valve spring seat 4 to the valve stem 1a via the compressor 5.

Here, in order to ensure wear resistance and fatigue resistance of the valve spring contact portion 4a of the valve spring seat 4, it is necessary to add 20% by weight or more of Si to the first aluminum alloy powder 11.
It is necessary to include the following. Furthermore, in order to prevent cranks and underfilling from occurring in the forged product 4A during forging of the blank 14, the St content of the second aluminum alloy powder 12 needs to be 16% by weight or less. However, in order to ensure the strength, hardness, wear resistance, and fatigue resistance of the parts other than the collar-shaped part 41) of the valve spring seat 4, the second aluminum alloy powder 12 contains a certain amount of St. It is necessary to be.

In the above embodiment, the blank 14 is formed into a cylindrical shape, but it may also be formed into a cylindrical blank by forming a blank material which is a cylindrical powder compact and removing the center part by cutting.

Alternatively, as shown in FIG. 10, the first aluminum alloy powder 11
It may be formed into a blank 14A of a powder compact comprising a flange portion 11 made of aluminum alloy and a cylindrical portion 12A made of second aluminum alloy powder 12 continuous to the lower end thereof.

[Brief explanation of the drawing]

Of the drawings, Figures 1 to 10 relate to embodiments of the present invention, with Figure 1 being a cross-sectional view of the main parts of the engine valve mechanism and cylinder head, and Figures 2 and 3 depicting powder powder. 4 is a cross-sectional view of a blank, and FIGS. 5 to 7 are cross-sectional views of main parts showing each stage of forging in a forging device. Figure 8 is a sectional view of the valve spring seat, Figure 9 is a sectional view of the valve spring surrounding portion of the valve mechanism, Figure 10 is a view corresponding to Figure 4 according to a modification, and Figures 11 to 14 are prior art. This is related to the 11th
The figure corresponds to FIG. 9, and FIGS. 12 to 14 correspond to FIG. 5 and FIG. 7, respectively. 4... Valve spring seat T-14a... Valve spring contact portion, 11... First aluminum alloy powder,
12...Second aluminum alloy powder, 14.14A
...Blank (powder compact), 15...Lower mold, 15a
・Concavity.

Claims (1)

[Claims] (1) A first aluminum alloy powder containing 20% by weight or more of Si and a second aluminum alloy powder containing 16% by weight or less of Si are molded so that one end in the axial direction is made of the first aluminum alloy powder. A powder compact made of powder, the remainder of which is made of secondary aluminum alloy powder, is produced, the remaining part of the powder compact is inserted into a recess of a forging die, and the powder compact is forged into a valve spring seat shape, and the valve is manufactured. A method for manufacturing an aluminum alloy valve spring seat, comprising manufacturing a valve spring seat whose spring contact portion is made of an aluminum alloy containing 20% by weight or more of Si.