JPH0763020A - Aluminum alloy made valve retainer - Google Patents

Abstract

PURPOSE:To reduce a weight, and also improve respective characteristics such as abrasion resistance, rigidity, and high temperature strength by constituting a valve retainer by a material whose aluminum alloy is formed as a matrix. CONSTITUTION:The material of a valve retainer 5 which k engagingly mounts the valve spring 7 for energizing a valve while being installed on a valve stem 4a as the construction member for a valve system mechanism in an engine, is composed of an aluminum alloy compound member in which aluminum alloy including Si as alloy element having 7.0 to 15 mass %, Cu having 0.5 to 6.0 mass %, and the other element having 5 mass % or less is formed as a matrix.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve retainer which is a constituent member of a valve operating mechanism of an engine. More specifically, it has a small mass in order to reduce the amount of friction loss to improve fuel consumption and increase engine speed. The present invention relates to an aluminum alloy valve retainer which uses an aluminum alloy as a material.

[0002]

2. Description of the Related Art FIG. 1 shows an assembled structure of an OHC (overhead camshaft) as an example of a valve operating system of an engine, in which 1 is a cylinder head and 2 is a cylinder head.
Is a cam shaft for rotating the cam 2a, 3 is a valve lifter, 4 is a valve connected to one end of the valve stem 4a, 5 is a valve retainer, 6 is a cotter, 7 is a valve spring, 8 is a spring seat, and 9 is a stem. Sheet, 1
Reference numeral 0 is a valve guide, 11 is a valve seat, and 12 is a combustion chamber.

The above-mentioned valve lifter 3 is composed of a cylindrical member having a ceiling wall, and a side surface portion 3a thereof is slidably fitted to a cylinder head processing surface (hole peripheral surface) 13 of the cylinder head 1. The top surface portion 3b of the valve lifter 3 is sandwiched between the cam 2a and the tip of the valve stem 4a.

A cotter 6 is fixed to the tip of the valve stem 4a, and a valve retainer 5 is arranged around the valve stem 4a via the cotter 6.
Further, one end of a valve spring 7 is engaged with the valve retainer 5, and the valve stem 7 constantly urges the valve stem 4a and the valve 4 upward (in the valve closing direction) in FIG.

Thus, as the cam 2a is rotationally driven by the camshaft 2, the valve lifter 3 is pressed downward and the valve 4 is moved to the open position, and the urging force of the valve spring 7 is applied. The step of returning the valve 4 to the closed position shown in FIG. 1 is sequentially repeated, and the vertical movement of the valve 4 at this time causes intake of the air-fuel mixture into the combustion chamber 12 and combustion from the combustion chamber 12. The gas is exhausted.

By the way, conventionally, as the valve retainer 5 which is one of the constituent members of the valve operating mechanism of the engine, a carbon steel such as S15C or S20C which is carburized and tempered is usually used. Has been done.

[0007]

The valve retainer 5 is
It is a component for holding the valve stem 4a and the valve 4 via the cotter 6 inside the valve lifter 3 in order to convert the rotational movement of the cam 2a into the vertical movement (or the horizontal direction) of the valve 4. The valve retainer 5 is in surface contact with the cotter 6 and is also in surface contact with one end of the valves spring 7 although it has a small area, and these contact surfaces slide little by little during engine operation. .

Therefore, as a characteristic of the valve retainer 5, the valve retainer 5 itself has excellent wear resistance, and the cotter 6 has
It is required to have less aggression to wear the valve spring 7 and the valve spring 7. Further, when the valve spring 7 is moved up, sufficient rigidity is required so that the cam 2a operates accurately according to the shape of the cam 2a. In particular, 100
Since it is heated to about 150 ° C, rigidity in that temperature range is required.

Further, since the valve retainer 5 repeats the reciprocating motion in the vertical direction (or the horizontal direction in the case of a horizontally opposed engine) together with the valve 4, it is desirable that the valve retainer 5 be as light as possible.

However, the conventional steel valve retainer 5
Has a large inertial mass, it is necessary to set the spring force of the valve spring 7 to be strong in order to normally maintain the motion of the valve train up to a high speed state. However, if the spring force of the valve spring 7 is set to be strong, the spring mass increases, the friction loss amount of the valve operating system increases in proportion thereto, and the fuel consumption deteriorates.

Therefore, recently, by reducing the mass, the spring force of the valve spring 7 is set to be relatively weak, thereby reducing the amount of friction loss to improve fuel consumption and increase the engine speed. Aluminum alloy valve retainers have been proposed. However, in this type of aluminum alloy valve retainer, since the material is aluminum alloy, the wear resistance at the contact portion with the cotter 6 and the valve spring 7 is insufficient, and the rigidity is also insufficient. Therefore, at present, the valve retainer made of aluminum alloy cannot be used as a substitute for the conventional product, and the valve retainer made of the above-mentioned steel material is used in reality.

When an aluminum alloy valve retainer 5 is used, not only wear resistance and rigidity but also high temperature strength (heat resistance) is a problem. As a method for improving wear resistance, it is possible to apply iron / phosphorus electroplating, electroless nickel / phosphorus plating, or iron alloy plating, but these methods are not enough to improve wear resistance. Notably, the improvement in rigidity and high temperature strength is slight.

The present invention has been made in view of the above circumstances, and an object thereof is to achieve weight reduction by constructing a valve retainer with a composite material having an aluminum alloy as a matrix, and further, It is to provide a valve retainer that has excellent characteristics such as wear resistance, rigidity, and high temperature strength.

[0014]

In order to achieve the above-mentioned object, in the present invention, a valve is attached to a valve stem as a component of a valve operating mechanism of an engine, and a valve spring for urging the valve is attached. Change the retainer material to
As an alloying element, Si is 7.0 to 15 mass%, Cu is 0.5 to 6.0 mass%, and an aluminum alloy composite material containing an aluminum alloy containing 5 mass% or less of other elements as a matrix is used. I have to.

The composite material is a particle-reinforced aluminum alloy, a fiber-reinforced aluminum alloy, or a hybrid of these.

The additive material added to the aluminum alloy composite material is 1 to 20 mass%.

When the additive material is particles, the particles have a Vickers hardness of 1000 or more,
The particle diameter is 0.5 to 20 μm.

When the additive material is particles and short fibers, the amount of the short fibers added is 50% or less in mass ratio with respect to the particles.

Further, an aluminum oxide film is formed on the surface of the valve retainer base made of the aluminum alloy composite material.

[0020]

[Function] The valve retainer is made of a composite material in which the aluminum alloy having the above composition is used as a matrix, so that the weight of the valve retainer can be reduced, the inertia force can be reduced, and the friction loss amount can be reduced. And improvement in engine speed are achieved. Further, the use of the aluminum alloy composite material makes the valve retainer excellent in characteristics such as rigidity and high temperature strength.

[0021]

Embodiments of the valve retainer according to the present invention will be described below with reference to FIGS.

First, the outline of the present invention will be described below before specifically describing the embodiments of the present invention. That is, according to the present invention, the valve retainer is made of a composite material in which an aluminum alloy is used as a matrix, and the above-described drawbacks are improved while the mass is almost the same as that of the aluminum alloy. Is.

As the material for the valve retainer, if a composite material in which ceramic particles or the like are dispersed in an aluminum alloy is used, it is lightweight and excellent in wear resistance, and has improved rigidity (including high temperature rigidity) and high temperature strength. can do.
A valve retainer manufactured from this material can be used as a substitute for the conventional steel valve retainer.

Further, as shown in FIG. 2, an aluminum oxide film (alumite layer, boehmite layer) 14 is formed by alumite treatment on the surface of the base body 5a of the valve retainer 5 made of a composite material using an aluminum alloy as a matrix.
May be formed. In this case, the presence of the aluminum oxide film 14 makes it possible to further improve the wear resistance and suppress the aggressiveness to the mating member.

However, the matrix of the composite material is an aluminum alloy, and the alloying element is 7.0-1.
It contains 5 mass% of Si and 0.5 to 6.0 mass% of Cu, and further contains 5 mass% or less of other elements such as Mg, Ni and Fe in total. Moreover, the additive material is 1 to
20 mass% is added.

When the additive material is particles, the Vickers hardness H _V is 1000 or more, and the particle size is 0.5 to 2
It shall be 0 μm.

A composite material in which short fibers such as whiskers are added together with the particles may be used, but in this case, the addition mass ratio to the particles is 0.5 or less, that is, the addition amount of the short fibers is the mass to the particles. The ratio is 50% or less.

Further, in order to improve the soundness of the material, a high temperature and high pressure (HIP) process may be performed. In this case, since the matrix is an aluminum alloy,
Even if it says high temperature, it is about 600 ° C or lower.

Next, a specific example to which the present invention is applied will be described below.

Concrete Example 1 A composite material (PRM; Particle Rein) in which 5 mass% of SiC particles having a particle diameter of 5 μm are added to a JIS AC8A alloy.
forced metal), that is, a grain-reinforced aluminum alloy was manufactured, and subjected to HIP treatment at 500 ° C., 1000 atmospheric pressure for 1 hour to improve the soundness of the material, and a valve retainer was manufactured using it. Then, a 20 μm aluminum oxide film (alumite layer or boehmite layer) was formed on the surface of the valve retainer.

The static strength characteristics and the fatigue strength characteristics of the aluminum alloy valve retainer thus obtained were measured, and the results shown in FIGS. 3 and 4 were obtained. Further, when the structure of the surface portion was observed with a microscope, the observation result as shown in FIG. 5 was obtained. In FIG. 5, 5a is a base of the valve retainer 5, and 14 is an aluminum oxide film.

Since this aluminum alloy valve retainer uses aluminum alloy as a matrix, it is lighter in weight than conventional products and has improved characteristics such as rigidity, wear resistance and high temperature strength. It was a part that could be replaced with a valve retainer made by Japan.

Example 2 A composite material (PRM) prepared by adding 10 mass% of SiC particles having a particle size of 5 μm to a JIS AC8A alloy was prepared, and the composite material was heated at 500 ° C., 1000 atmospheric pressure for 1 hour to improve the soundness of the material. HIP processing was performed and the valve retainer was manufactured using it. Then, a 20 μm aluminum oxide film (alumite layer or boehmite layer) was formed on the surface of the valve retainer.

The aluminum alloy valve retainer thus obtained is lighter than the conventional product and has improved characteristics such as rigidity, abrasion resistance and high temperature strength, as in the case of the above-mentioned first embodiment. It was a part that could be replaced with a conventional steel valve retainer.

The embodiment of the present invention has been described above.
The present invention is not limited to this embodiment, and various modifications and changes can be made based on the technical idea of the present invention. For example, although the particle-reinforced aluminum alloy (PRM) is used as the composite material in the above-described specific examples, a fiber-reinforced aluminum alloy (FRM; Fiber Reinforced Metal) or a hybrid thereof may be used as the composite material. Good.

[0036]

As described above, according to the present invention, the material of the valve retainer, which is a constituent member of the valve mechanism, is made of the aluminum alloy composite material having the matrix of the aluminum alloy having the predetermined range of composition as described above. As a result, the valve retainer of the present invention can be made significantly lighter than the conventional steel valve retainer by using the aluminum alloy composite material. As a result, the inertial force of the valve retainer can be reduced, which in turn can improve fuel efficiency by reducing the amount of friction loss and speed up the engine.

Moreover, in addition to the above effects, the use of the aluminum alloy composite material makes the valve retainer excellent in various properties such as wear resistance, rigidity and high temperature strength. Therefore, there is no problem even if the valve retainer of the present invention is used as a substitute for the conventional steel valve retainer, and it is possible to obtain the practical operational effects as described above.
Very informative.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a valve operating mechanism of an engine.

FIG. 2 is a cross-sectional view showing an aluminum oxide film formed on the surface of a valve retainer substrate.

FIG. 3 is a graph showing static strength characteristics of the valve retainer according to the present invention.

FIG. 4 is a graph showing fatigue strength characteristics of the valve retainer according to the present invention.

FIG. 5 is a micrograph showing a metal structure of a surface portion of a valve retainer according to the present invention.

[Explanation of symbols]

1 Cylinder Head 2a Cam 3 Valve Lifter 4 Valve 4a Valve Stem 5 Valve Retainer 5a Valve Retainer Base 7 Valve Spring 14 Aluminum Oxide Film (Alumite Layer, Boehmite Layer)

Claims (6)

[Claims] 1. A material for a valve retainer, which is attached to a valve stem as a component of a valve train of an engine and to which a valve spring for urging a valve is attached, has a mass of Si of 7.0 to 15 as an alloying element. %, Cu 0.5
A valve retainer made of an aluminum alloy, characterized in that the valve retainer is made of an aluminum alloy composite material whose matrix is an aluminum alloy containing up to 6.0 mass% and other elements in an amount of 5 mass% or less. 2. The valve retainer made of an aluminum alloy according to claim 1, wherein the composite material is a particle-reinforced aluminum alloy, a fiber-reinforced aluminum alloy, or a hybrid thereof. 3. The aluminum alloy valve retainer according to claim 2, wherein the additive material added to the aluminum alloy composite material is 1 to 20 mass%. 4. When the additive material is particles, the particles have a Vickers hardness of 1000 or more and a particle diameter of 0.5 to 20 μm.
Aluminum alloy valve retainer described in. 5. The aluminum alloy according to claim 3, wherein when the additive material is particles and short fibers, the amount of the short fibers added is 50% or less in mass ratio with respect to the particles. Valve retainer. 6. An aluminum oxide film is formed on the surface of a valve retainer substrate made of the aluminum alloy composite material.
The aluminum alloy valve retainer according to claim 5.