JP2709097B2 - Spring retainer - Google Patents

Description

The present invention relates to an engine engine, and more particularly to a spring retainer incorporated in a valve train of an engine engine.

[Conventional technology and issues]

A valve mechanism of a conventional engine engine is, for example, as shown in FIG. That is, the valve guide 2 is provided on the cylinder head 6, and the valve stem 3 is supported on the valve guide 2 so as to be slidable in the vertical direction. A valve face 4 is provided at a lower end of the valve stem 3, and the valve face 4 is brought into contact with and separated from a valve seat 5 of an intake / exhaust port to open / close the intake / exhaust port.

The spring retainer 1 is fixed to the upper end of the valve stem 3 via a cotter 7. A valve spring 8 is interposed between the spring retainer 1 and the upper surface of the cylinder head 6, and the valve spring 8 urges the valve face 4 in a direction for seating on the valve seat 5.

A hollow shaft-shaped rocker shaft 10 to which lubricating oil is supplied is provided above the cylinder head 6, and a rocker arm 11 is slidably mounted on the rocker shaft 10. One end of the rocker arm 11 abuts on the upper end of the valve stem 3, and the other end of the rocker arm abuts on a push rod 12 for transmitting the movement of a valve lifter (not shown). That is, when the other end of the rocker arm 11 is pushed up by the push rod 12, the valve stem 3 is pushed down, the valve face 4 is separated from the valve seat 5, and the suction / exhaust port is opened. Push rod 12
When the valve retainer 1 is lowered, when the spring retainer 1 is pushed up by the action of the valve spring 8, the valve stem 3 connected via the cotter 7 is raised, and the suction / exhaust port is closed.

By the way, such a spring retainer 1 is conventionally a JISA G
High-strength steels such as chromium molybdenum steel specified in 4105 have been used. However, as can be seen from the function of the spring retainer 1 described above, the valve retainer has a large thermal conductivity for quickly dissipating the heat generated from the valve-spring system, and an inertia for reducing the load on the valve and the spring. A small mass was desired.

[Means for solving the problem]

Therefore, in order to solve the above-mentioned problem, an aluminum alloy (having a thermal conductivity four times that of steel and a mass of one-third of steel) can be considered. For this reason, the present inventor improved the wear resistance by blending the relatively high-ceramic ceramic particles or relatively soft ceramic particles among the high-Si aluminum alloy powders containing bacteria and Fe, Mn, which were developed with bacteria, into the aluminum alloy. It has been confirmed that the mating material becomes an excellent spring retainer without wear, and a proposal was made (Japanese Patent Application No. 63-8684).
2). The present invention relates to the improvement of the above invention, and further improves durability and lubricity.

That is, the gist of the present invention is as follows.
And 30.0%, containing a Fe0.5～7.0% and Mn0.5～4.0% in a matrix consisting of Al alloy balance including inevitable impurities, Al ₂ having an average particle 2 to 30 m O ₃ -ZrO ₂ A spring retainer in which SiO ₂ ceramic particles are dispersed in a weight ratio of 1 to 10%, and a second is a silica 0.0 to 30.0% in a weight ratio.
And Fe 0.5-7.0% and Mn 0.5-4.0%, and further Cu
Al ₂ O ₃ —ZrO ₂ —SiO ₂ -based ceramic particles having an average particle size of _{2 to 30} μm are contained in a matrix composed of an Al alloy containing 0.5 to 5.5% and 0.2 to 3.0% of Mg and the balance including unavoidable impurities. It is in a spring retainer that is dispersed by 1 to 10% by weight.

[Configuration of the invention]

 Hereinafter, the present invention will be described in detail.

In the present invention, an aluminum alloy powder described in JP-A-61-295301, which has abrasion resistance and toughness even at a high temperature, is used as a base material.

 The reasons for limiting the components in the present invention are as follows.

If the content of Si is 10% by weight or less, the amount of dispersion is small, and the effect on heat resistance and wear resistance is insufficient. In the hypoeutectic region of about 10% by weight of Si, the primary crystal Si does not crystallize and exhibits a fine eutectic structure. As the amount of Si increases, a primary crystal of Si comes to crystallize, and heat resistance and abrasion resistance improve. However, if the Si content exceeds 30% by weight, coarse Si primary crystals do not disappear even if powdering is performed using any rapid solidification method. Even at a quenching rate of about 10 ³ ° C / sec, it is necessary to reduce the amount of Si to 25% by weight or less in order to refine the primary crystal Si.

In performing extrusion molding of an Al alloy powder having a coarse Si primary crystal structure, the compactibility of the powder is extremely poor, so that molding of a green compact is difficult. In addition to requiring a large and large pushing force, the result is that the life of the extrusion die is significantly shortened.

Therefore, the Si content is 10.0 to 30% by weight, preferably Si 1
It is good to be 3.0 to 25% by weight.

Fe and Mn are important components in the present invention.
Since Fe and Mn have low solubility in Al and a low diffusion rate, they disperse and crystallize as fine intermetallic compounds, and improve the high-temperature strength of the material. Further, the important role of Fe and Mn is to improve stress corrosion cracking resistance. The present inventors have studied the stress corrosion cracking resistance in detail, and as a known Al alloy, adding Fe or Mn alone has no effect on the stress corrosion cracking resistance, The present inventors have found that coexistence of Fe and Mn in a certain range has a remarkable effect, leading to the present invention.

Usually, Fe and Mn present in the Al metal, respectively,
At most, it is about 0.8% by weight and 0.03% by weight, and this level is insufficient for high temperature strength and stress corrosion cracking resistance. On the other hand, if the addition amount is too large, the hot workability and the toughness decrease, which is not preferable.

When Fe and Mn are added beyond the solid solution limit, Al-Fe-
It precipitates as an Mn-Si based intermetallic compound, and its shape becomes coarser as the amount of addition increases and as the cooling rate decreases. This intermetallic compound exists as a rod-like structure in the alloy powder obtained by the dispersion quenching and solidification method, is separated in the subsequent hot extrusion step, and is finely dispersed in the matrix. This compound is stable even at a high temperature, does not grow coarsely, and does not decrease in strength even when kept at a high temperature for a long time.

Further, this intermetallic compound is an Al-Fe-based or Al-Fe-based compound.
It has a remarkable effect on stress corrosion cracking resistance as compared with Mn-based intermetallic compounds.

Therefore, it is suitable as a material for mechanical parts that are exposed to high temperatures and require high strength, such as cylinder liners, pistons, connecting rods, rocker arms, compressor blades, and the like. In particular, it can be an optimal material for a mechanical component that requires a long life and high reliability in which stress corrosion is a problem. Appropriate amounts of Fe and Mn are 0.5 to 7% by weight of Fe and 0.5 to 4% by weight of Mn. When Fe exceeds 7% by weight or Mn exceeds 4% by weight, hardness and wear resistance are rather lowered, and when a molded body is formed, the material tends to be brittle.

The reason for reducing the Mn content as compared with Fe is to improve hot workability, improve extrusion yield, improve stress corrosion cracking, and improve toughness.

Also, Fe and Mn do not show resistance to stress corrosion cracking when added alone, and it is necessary to add both at the same time.

In the Al alloy powder of the present invention, Cu or Mg may be added as necessary. Cu and Mg are widely used as components for imparting age hardening properties and strengthening the material in Al alloys. Suitable amounts of Cu are 0.5 to 5.0% by weight, and Mg is 0.2 to 3.% by weight. Range. Also in the present invention, the addition of Cu and Mg within the range of the solid solution limit at the solution treatment temperature is effective for strengthening the material. In the alloy powder of the present invention, addition of a small amount of Ti, Zr, Mo, V, Co, Zn, Li or the like for the purpose of improving the high-temperature strength does not cause any problem. However, if the addition amount is too large, problems in production such as component management and increase in dissolution temperature occur.

The size of the Si crystal grains in the Al alloy powder is preferably 15 μm or less, mainly because when the size of the primary crystal Si becomes 15 μm or more, the formability of the subsequent alloy powder deteriorates, and the material properties deteriorate. .

The Al alloy powder of the present invention is obtained by atomizing a molten alloy having the target composition by an atomizing method, a fine powder manufacturing method by centrifugal force.
It is obtained by rapid dispersion coagulation to a particle size of 0.5 mm or less. It is sufficient that the cooling rate at the time of powdering is about 10 ³ ° C / sec or more, and a fine structure cannot be obtained unless the cooling rate is increased as the alloy component amount increases. The size of the Al alloy powder thus obtained is
It has a Si crystal of 15 μm or less and an intermetallic compound crystal whose growth is suppressed, and it is difficult to obtain such a structure by a casting method.

As the ceramic particles, alumina (Al ₂ O ₃ ) -zirconia (ZrO ₂ ) -silica (SiO ₂ ) particles are used. Al
₂ O ₃ —ZrO ₂ —SiO ₂ -based ceramics are softer than Al ₂ O ₃ alone particles, have a small degree of damaging the mating material, and have sufficient hardness to improve wear resistance. The composition range of the ceramic is _{Al 2 O 3: 45~55wt%,} ZrO 2: 25~35wt%, SiO
₂ : 15 to 25 wt% is appropriate. If Al ₂ O ₃ is less than 45 wt%, the wear resistance is not improved, and if it is more than 55 wt%, ZrO ₂ which is too hard and damages the mating material works to soften the hardness, and SiO ₂ works to improve lubricity. . In order to supplement the function of Al ₂ O ₃ , ZrO ₂ and SiO ₂ each contain 25 to 35 wt%, 15
It must be contained in an amount of up to 25 wt%. As such ceramic particles, Morundum AZ manufactured by Showa Denko KK can be used. Of course, a spherical shape is more preferable. The average particle diameter of the ceramic is preferably 2 to 30 μm. If the average particle size is less than 2 μm, the particle size is too small to provide a sufficient abrasion resistance effect. If the average particle size is 30 μm or more, hot working becomes difficult and strength decreases.

The added amount of the ceramic particles needs to be 1 to 10% by weight. If the content is less than 1 wt%, the effect of addition will not be exhibited, and if it exceeds 10 wt%, the effect of addition will be saturated and the strength of the material will be reduced.

As a method for dispersing the ceramic particles, any of a method of dispersing in an aluminum alloy melt and a method of mixing and extruding with an aluminum alloy powder may be used, but it is preferable to mix and use the alloy particles. The reason is that it is considerably difficult to uniformly disperse a large amount of ceramic particles with a molten aluminum alloy. A method for obtaining a formed body composed of ceramic particles and an aluminum alloy is, for example, as follows.

An aluminum powder alloy is obtained from a molten aluminum alloy by a known method such as an atomizing method or a centrifugal pulverization method.
A predetermined amount of ceramic particles are blended with this aluminum powder alloy, and uniformly mixed with a V-shaped cone mixer or the like. Then, the obtained mixed powder is heated to 200 to 350 ° C. and compression-molded. The molding pressure may be about 0.5 to ³ ton / cm ² . Then, hot extrusion may be performed at a temperature of 350 ° C. or more, preferably 400 to 500 ° C. The molded product may be subjected to a heat treatment such as annealing, quenching, or tempering if necessary to improve the strength of the alloy. Finally, with a small operation such as hot forging, a spring retainer is obtained as the final product.

 Next, an example of the present invention will be described.

(Example 1) Si 14.5%, Cu 2.5%, Mg 0.5%, Fe 4.5%, Mn 2.0
%, And the cooling rate is 10 ³ -10 ⁴ ℃ / sec by air atomizing a high Si aluminum alloy melt having an alloy composition with the balance being Al
Quenched as a rapidly solidified powder, the resulting powder is -60me
We sieved to make sh.

3 wt% of the hard ceramic particles shown in Table 1 were added to this aluminum alloy powder and mixed using a V-type mixer. Samples a and b were pressed at a density of 75% by a press molding method (CIP method). A powder was obtained. In cold isostatic pressing, the mixed powder is placed in a rubber tube and the pressure is 1.
It was formed under a hydrostatic pressure of about 5 to 3.0 ton / cm ² . For samples c and d, green compacts having a density ratio of 75% were obtained by a die compression molding method. In the mold compression molding method, the mixed powder was placed in a mold and molded at a pressure of about 1.5 to 3.0 ton / cm ² in a normal temperature atmosphere.

The green compact thus obtained is kept in a soaking furnace at a furnace temperature of 400 ° C. for 4 hours, and then subjected to hot extrusion with the green compact to form a round bar having a diameter of 20.5 mm and a length of 400 mm. Was obtained.

After performing the heat treatment shown in Table 2 on the extruded rod, a test piece for tensile test specimen SCC test was cut out, and the tensile test, SCC test,
A tensile test was performed after exposure to air at 150 ° C. for 2,000 hours.
Table 3 shows the test results.

For comparison, 17.5Si-2.9Cu-1.0, which is shown as Test Material No. 3 in the examples of JP-A-61-295301.
Mg-4.2Fe-2.1Mn-Residual aluminum alloy with no hard ceramic particles added, T6 treatment applied when maximum strength is required, and no heat treatment A similar test was performed for the case of The test results are shown in Table 3.

(Example 2) Si 14.5%, Cu 2.2%, Mg 0.4%, Fe 4.5%, Mn 2.0
%, And a high Si aluminum alloy melt having an alloy composition with the balance being Al was atomized by air to form a rapidly solidified powder, and the obtained powder was sieved to −60 mesh. Then, average particle 10 μm composition Al ₂ O ₃ : 50.6%, ZrO ₂ : 31.
Morundum AZ particles manufactured by Showa Denko KK having a composition of 1%, SiO ₂ : 16.8%, Fe ₂ O ₃ : 0.1%: TiO ₂ 1.1% were blended with the rapidly solidified powder so as to be 5% by weight. And using a V-type cone mixer under nitrogen gas charging. After heating these mixed powders to 250 ° C. for 1 hour, they were filled into a mold heated to the same temperature, and compression-molded with upper and lower punches to form billets. Next, the billet was heated at 450 ° C. for 30 minutes in Ar gas, and then a round bar was obtained by hot extrusion. afterwards,
A blank for forging was placed in a mold for molding a spring retainer heated to about 430 ° C., and pressed from above and below to form a spring retainer material by hot forging. After the material was T6 treatment, it was subjected to material testing, tensile strength 44.2kgf / mm ^2, 0.2% proof stress 38f / mm ^2, elongation of 0.6%, the hardness (HRB) 93, Sharubi impact value 0.50 kgf / mm ^Two .

(Wear test) A wear test of the aluminum alloy-ceramic composite material thus produced was performed.

The test was performed by the method shown in FIG. The test piece 13 is held by a test piece holder 14 and pressed against the outer peripheral surface of the counterpart rotating disk 15 at a constant pressure, and slid while supplying lubricating oil from a lubricating oil supply pipe 16. The test piece has a prism shape of 5 × 5 × 20 mm, and the sliding surface at the tip is rounded with a radius of 6 mm and polished. The counterpart disk 15 is AA standard 390 number aluminum alloy (Si17%, Cu4.5%, Mn0.55%, balance is Al)
T6 treated (tempered at 480 ° C and then tempered at 120 ° C for 24 hours), has a hardness of HRB 80, an outer diameter of 44.2mm, and the sliding outer peripheral surface is polished to a surface roughness of about 1.5μm. Have been. With such a device, the counter disk 15 is rotated at a peripheral speed of 3 m / s, and a compressor oil heated to 80 ± 1 ° C. (SUNISO 5GS is supplied at a rate of 500 ml / min from a supply pipe while a test piece is being supplied. 13 was pressed against the outer peripheral surface of the counterpart disk 15 with a pressing force of 3 kg / mm ² , and the test piece 13 and the counterpart disk 15 were slid with a friction distance of 150 km.

 Table 4 shows the results of the wear characteristic test.

As is evident from Table 4, the product of the present invention has characteristics close to those of chromoly steel, which is currently used as a spring retainer.

The spring retainer material was subjected to mechanical processing such as grinding to produce the spring retainer 1 shown in FIG. This spring retainer 1 is 9mm long,
Outer diameter 32mm, outer diameter of cylindrical part 17 15mm, diameter of large diameter end of conical surface 18 11mm, inclination angle of conical surface 18 15 °, thickness of flange 19
4 mm. In order to evaluate the performance of the spring retainer, a test for assembling it into an actual gasoline engine was performed, and it was confirmed that the spring retainer had sufficient durability. Also, no substantial wear occurred on the spring retainer and the valve spring. Furthermore, the weight of the spring retainer is 10.1 g, and the conventional spring retainer made of chromium molybdenum steel is about 20 to 30 g, but the weight has been reduced to 1/2 to 1/3.

(Example 3) Si 16.5%, Fe 5.5%, Mn 2.
A spring retainer was produced in the same manner as in Example 2 except that an alloy containing 5% was used and subjected to O (O) treatment. The mechanical properties of this material are tensile strength 40.1kgf / mm ^2, 0.2
% Proof stress 35.2 kgf / mm ² , elongation 0.45%, hardness (HRB) 91, Charpy impact value 0.41 kgf / mm ² .

From these results, it is clear that according to the present invention, it is possible to provide an aluminum alloy having heat resistance, high rigidity, high wear resistance, and SCC resistance, which cannot be obtained with conventional aluminum alloys. Was.

〔The invention's effect〕

The spring retainer according to the present invention is
(B) The heat conductivity is large and the heat generated from the valve-spring system can be easily dissipated. (C) The spring retainer does not wear out.
(D) There is an effect that the valve spring, which is the mating material, is not worn.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing one embodiment of the present invention. FIG. 2 is a schematic diagram showing a wear tester, and FIG. 3 is a schematic diagram showing the operation of a spring retainer. 1 ... Spring retainer, 2 ... Valve guide, 3 ...
... valve stem, 4 ... valve face, 5 ... valve seat, 11 ... rocker arm, 13 ... test piece, 14 ...
Specimen holder 15… Rotating disk, 17… Cylindrical part, 18… Conical surface, 19 ……
Flange part.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Haruo Shiina 1-4-1 Chuo, Wako City, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Masami Hoshi 1-4-1 Chuo Wako City, Saitama Prefecture Honda Co., Ltd. Inside the Technical Research Institute (56) References JP-A-61-295301 (JP, A)

Claims (4)

(57) [Claims] (1) Sil0.0-30.0% and Fe0.5-7.0% by weight.
And Mn 0.5 to 4.0%, the balance being in an Al alloy matrix containing unavoidable impurities, an average particle size of 2 to 30 μm.
In _{m, Al 2 O 3: 45~55wt} %, ZrO 2: 25~35wt%, SiO 2 15~2
Ceramic particles having a composition of 5 wt% are mixed in a weight ratio of 1-1.
A spring retainer characterized by being dispersed by 0%. (2) Sil 0.0-30.0% and Fe 0.5-7.0% by weight.
And Mn 0.5-4.0%, and further Cu 0.5-5.0% and
In a matrix composed of an Al alloy containing 0.2 to 3.0% Mg and the balance containing unavoidable impurities, with an average particle size of 2 to 30 μm,
_{Al 2 O 3: 45~55wt%,} ZrO 2: 25~35wt%, SiO 2 15~25wt%
A spring retainer characterized in that ceramic particles having the following composition are dispersed in a weight ratio of 1 to 10%. 3. The aluminum alloy matrix according to claim 1, wherein said aluminum alloy matrix is an aluminum alloy powder compact.
The described spring retainer. 4. The spring retainer according to claim 1, wherein the size of Si crystal grains in the Al alloy matrix is 15 μm or less.