JPS6196014A - Valve driving system sliding member and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture the titled member superior in wear resistance inexpensively, by setting wear resistant member material composed of Ni system or Co system alloy on iron system base material, heating said member material locally to generate liquid phase, then cooling rapidly and solidifying said material. CONSTITUTION:Wear resistant member material composed of compacted body or Co alloy powder is set on iron base material, and heated locally to temp. in which liquid phase is generated or above, so that 20-80% liquid phase ratio is obtd., then cooled rapidly and solidified. By this way, the titled member having high density, sufficient wear resistance, high degree of freedom in material selection, in which Ni or Co sintered alloy composed of hard phases having 1-50mum average particle diameter, 600-1,800Hv hardness are dispersed uniformly by 5-80% area ratio in Ni or Co matrix, is melted and joined with iron base material in one body, is obtd. with low manufacturing cost.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a sliding member of a valve train system having a sliding portion bonded with a wear-resistant material.

Conventional technology Sliding parts of internal combustion engine valve train members, such as the top of the valve lifter, valve face and pulp tip, valve seat face, rocker arm pad, etc., are required to have extremely high wear resistance. Ru. For this reason, conventionally, steel materials whose hardness has been increased through heat treatment or cast iron have been used, and as the required characteristics have become more stringent, materials have been used that are joined by casting a sintered alloy only on the sliding parts of valve train components. .

Problems to be Solved by the Invention However, the above-mentioned conventional valve train sliding members still do not have sufficient wear resistance, and there has been a demand for valve train sliding members that can meet even more severe usage conditions. .

In addition, there are also problems in that, particularly when steel or cast iron is used, there is little freedom in material selection, and on the other hand, when a sintered alloy is used, the manufacturing process becomes complicated and costs are high.

This invention has been made in view of the above-mentioned conventional circumstances, and is a valve train sliding member that has a high degree of freedom in material selection, has high density and sufficient wear resistance, and is low in manufacturing cost. The purpose is to provide the following.

Means for solving the problem, that is, the valve train sliding member of the first invention of this application is made of Ni.
Or, a hard phase with an average particle size of 1 to 50 degrees and a hardness of Hv 600 to 1800 is present in a Co-based matrix at an area ratio of 5 to 8.
The valve train slide of the second invention of this application is characterized in that a Ni or Co-based sintered alloy uniformly dispersed at 0% is integrally fusion-welded to an iron-based base material. A method for manufacturing a moving member includes installing a wear-resistant member material made of a green compact or pre-sintered body of Ni or Co-based alloy powder on an iron-based base material;
The liquid phase ratio of the wear-resistant part material installed on the iron base material is 2.
It is characterized in that it is locally heated to a temperature above the liquid phase generation temperature so that it becomes 0 to 80%, and then rapidly solidified.

Detailed description of the invention This invention will be explained in more detail below.

The valve train sliding member of the first invention of this application is made of Ni or C.
O-based matrix with average particle size of 1 to 50 degrees and hardness of Hv
Ni or c in which a hard phase having a molecular weight of 600 to 1800 is uniformly dispersed at an area ratio of 5 to 80%.

A sintered alloy is integrally fusion-welded to a ferrous base material.

The purpose of using a Ni or Co-based sintered alloy in which a hard phase is uniformly dispersed in a Ni- or Co-based matrix is to ensure wear resistance such as scuffing resistance. Moreover, it is preferable that the average particle size of the hard phase is 1 to 50.

This is because if the IJJP is less than 1, the wear resistance will be insufficient, and if it exceeds 50JJl, the aggressiveness against the opponent will be excessive. However, it is more preferably 10 to 45,371 m, and most preferably 15 to 40 m. Furthermore, that I
i! The hardness of the texture is preferably Hv600-1800.

If Hv is less than 600, wear resistance is insufficient, and Hv18OO
This is because, if the value is exceeded, the opponent's aggressiveness increases rapidly.

In addition, the distribution amount of the hard phase is preferably 5 to 80% in terms of area ratio. This is because if the area ratio is less than 5%, the wear resistance is insufficient, and if it exceeds 80%, the aggressiveness against the opponent increases rapidly. However, the area ratio is more preferably 15 to 10%, and most preferably 25 to aθ%.

Note that as the iron-based base material, ordinary carbon steel, high carbon special steel, etc. can be used.

Now, the above Ni or Co-based sintered alloy of the first invention is as follows:
Residual porosity is 2% or less, apparent hardness is Hv450-10
Preferably it is 00.

The reason why the residual porosity of the N1 or Co-based sintered alloy is set to 2% or less is that if the porosity exceeds 2%, the sliding part of the resulting valve train sliding member will be affected by the high surface pressure conditions of the valve train. This is because, if exposed downward, pitching tends to occur in the sliding portion, which is inconvenient. However, the porosity is more preferably 1.8% or less, and most preferably 1.5% or less.

Also, look at Ni or Co-based sintered alloys! ) hardness Hv4
The reason why it is set to 50 to 1000 is that if it is less than Hv450, the wear resistance is insufficient, and if it exceeds Hvloooo, not only will the aggressiveness of the opponent increase, but also the rigidity will be poor, making it difficult to finish the sliding part. However, more preferably, the apparent hardness is Hv
It is better to set 550=950, most preferably Hv
It is good to set it to 600-950.

From the first point of view regarding its components, the above N1 or Co-based sintered alloy contains 1.0 to 40% Cr (2.0 to 40% Cr in the case of a Co-based sintered alloy), and Mo0
．． 1-5.0%, W0.5-10%, ■0.1-6.0
%, Nb 0.05-3.0%, Ta0005-1.5
Contains one or more of the following, and the remainder is C00
It is desirable that the content be 3 to 3.5%, Ni or Co, and impurities of 2% or less.

The reasons for limiting each component of the N1 or Co-based sintered alloy are described below.

Cr is 1.0 to 40% (C.

In the case of sintered alloys, it is preferable to add 2.0 to 40%). Cr is less than 1.0% (in the case of Co-based sintered alloy, 2
If the Cr content exceeds 40%, coarse C carbides will be formed, which is not preferable. It is better to set C' to 1O-L30%.

Mo also has the same effect as Cr, and is preferably added in an amount of 0.1 to 5.0%. If the amount is less than 0.1%, no effect will be seen, and on the contrary, if it is added in excess of 5.0%.

It acts synergistically with cr, causing significant coarsening of carbides, which is not preferable. However, more preferably Mo is 0.5 to 4.
It is best to add 5% MO, most preferably 1.0~
It is best to add 4.0%.

In addition, W also has the same effect as Cr and MO, and has an effect of 0.5 to 1
It is preferable to add 0%. If it is less than 0.5%, no effect will be seen, and if it is added in excess of 10%, coarse carbides will be produced, which is not preferable. However, more preferably W is 1.0
It is best to add ~8.0%, most preferably 1.5~
It is best to add 1.5%.

Furthermore, (1) also contributes to improving wear resistance, and is preferably added in an amount of 0.1 to 6.0%. Addition of less than 0.1% has no effect, and addition of more than 6.0% causes coarse carbides, which is not preferable. However, it is more preferably added in an amount of 0.5 to 5.0%, most preferably 1.0 to 4.5%.

In addition, Nb also contributes to improving wear resistance, with a content of 0.05 to 3
．． It is preferable to add 0%. If it is less than 0.05%, the addition has no effect, and if it exceeds 3.0%, coarse carbides are produced, which is not preferable.

Furthermore, Ta also contributes to the improvement of wear resistance, and 0.05
It is preferable to add up to 1.5%. If it is less than 0.05%, the addition has no effect, and if it exceeds 1.5%, coarse carbides will be produced, which is not preferable. However, more preferably 0.1 to 1.
It is best to add 3%, most preferably 0.2 to 1.0
It is better to add %.

It is not necessary that all of the above Or 2 , Mo 2 , and W1V%Nb 1Ta be added at the same time, and one or more types may be added depending on the specifications of the valve train MTo member.

C strengthens the matrix and also contributes to improving wear resistance by forming carbides of other alloying elements.

Furthermore, an appropriate amount is required to lower the melting point of the iron-based alloy powder before sintering and ensure a low melting point liquid phase during sintering, and for the above reasons, it is added in an amount of 0.3 to 3.5%. .

If it is less than 0.3%, the effect of addition cannot be obtained sufficiently, and 3.
If it exceeds 5%, not only will the carbides become coarse, but also graphite will remain in the matrix of the sintered alloy more than necessary, and the remaining graphite will become long and thin, which will adversely affect pitting resistance and wear resistance, which is undesirable. However, it is more preferably added in an amount of 0.7 to 3.0%, most preferably 1.0 to 2.5%.

Furthermore, among the above Ni or Co-based sintered alloys, for the N+-based sintered alloy, from a second viewpoint, the components are Cu1.0-5.0%, Fe1.0-20%, Co1
, 0-20%, Si 0.1-1.5%, Mn001
~1.5%, P0.1~0.8%, B 0.01~0.
It is desirable to contain one or more of these 5%.

Below, the reason for limiting the components added from the above second viewpoint will be described.

Cu and Fg 1Co each form a solid solution in the matrix to strengthen the matrix. Also, Fe, C.

In particular, it increases the toughness of the matrix, and a part of it dissolves in the carbide that forms the hard phase dispersed in the matrix, increasing the adhesion of the carbide to the matrix. For that reason, C(+ is 1.0-5.0%, Fe is 1.0-5.0%
20%, and Co is added in an amount of 1.0 to 20%. That is,
There is no effect when added below the lower limit, and no improvement in effect is observed even when added above the upper limit. However, more preferably Qu is 1.2 to 4.5% and Fe is 2.0%.
~8.0%, G.

is preferably added in an amount of 3.0 to 18%, most preferably Cu is added in an amount of 4% to 2, fe is added in an amount of 2.5 to 7.0%, and co is added in an amount of 4%.
．． It is preferable to add 0 to 15%.

3i is added in an amount of 0.1 to 1.5% to strengthen the matrix by dissolving it in the matrix. If it is less than 0.1%, no effect is observed, and if it is added in excess of 1.5%, there is no improvement in the effect. However, preferably 0
．． It is best to add 2 to 1.3%, most preferably 0.
It is preferable to add 5 to 1.0%.

Mn is similarly dissolved in the matrix to strengthen the matrix, and is added in an amount of 0.1 to 1.5% for that purpose. 0.1
If it is less than 1.5%, there is no effect, and if it exceeds 1.5%, no further improvement in the effect is observed, which is not preferable. However, it is more preferable to add 0.2 to 1.3%, and most preferably 0.5 to 1.0%.

In addition, the above 81 and Mn exhibit a deoxidizing effect in the liquid phase during sintering by being included in the Ni-based alloy powder that is the raw material for the Nl-based sintered alloy, and also lower the melting point of the raw material powder. It also shows the effect of forming a liquid phase with a low melting point.

P is added mainly for the effect of forming a low melting point liquid phase,
It also has the effect of solid-dissolving in the matrix to strengthen the matrix, and is added in an amount of 0.1 to 0.8%. If it is less than 0.1%, it has no effect, and if it exceeds 0.8%, the matrix becomes brittle, which is not preferable.

B is also added in an amount of 0.01 to 0.5% for the same reason as P.

If it is less than 0.01%, it has no effect, and if it exceeds 0.5%, no improvement in the effect can be expected.

The above Cu, Fe, CD, Si, Mn, P, B
Each of the elements may be added individually in the form of a grass, but it is better to use one or more types of alloy powder, such as carbide powder, or to mix it with such an alloy powder to improve the structure obtained. It is effective in making the hard phase uniform and also effective in preventing the coarsening of the dispersed hard phase. However, when C is added separately in the form of graphite or the like, it is useful for reduction during heating and sintering of the raw material powder, and it is also recognized that it has the effect of promoting the formation of a low gender point liquid phase.

Next, the method for manufacturing a valve train sliding member according to the second invention of this application will be described in more detail.

First, in the manufacturing method of the present invention, a wear-resistant member material made of a green compact or a preliminary sintered body of Ni or CO alloy powder is placed on an iron base material. As the Ni or Co-based alloy powder, Or, M0. WlV.

Nb, Ta, C, Cu, Fe, Si, Mn
,P.

Sprayed alloy powders, other reduced powders, and electrolytic powders containing one or more than 28 of B can be used. Further, as the iron-based base material, ordinary carbon steel, high carbon steel, chilled cast iron, etc. can be used. When installing the wear-resistant part material on the iron-based base material, the wear-resistant part material is pre-formed into a predetermined shape and is placed in a recess formed in the desired position of the iron-based base material according to the shape of the wear-resistant part material. It is possible to use means such as fitting in place.

Next, in the present invention, the wear-resistant part material placed on the iron-based base material is locally heated to a temperature equal to or higher than the liquid phase generation temperature so that the liquid phase ratio becomes 20 to 80%. The reason why the liquid phase ratio is set to 20-6 or more is that if the liquid phase ratio is less than 20%, it is difficult to reduce the residual porosity of the obtained sintered body to 2% or less, and the manufactured dynamic This is because if the sliding portion of the valve system sliding member is exposed to high surface pressure conditions of the valve system, pitching tends to occur in the sliding portion, which is inconvenient. The reason why the liquid phase ratio is set to 80% or less is because if the liquid phase ratio exceeds 80%, segregation tends to occur in the melt, and it becomes necessary to add some kind of stirring effect. . However, more preferably the liquid phase ratio is 35
~65%, most preferably 40~55%
It is better to

In the above cases, the liquid phase generation temperature varies depending on the type of alloy powder used, and can be appropriately adjusted by adjusting the additive elements.

As a means of local heating, use a heat source that can concentrate energy as high as necessary, depending on the size of the two moving parts of the intended valve train sliding member and other specifications. For example, heating with a laser beam ff1l, plasma arc or plasma jet, application of a TIG welding torch, or other means can be applied.

Finally, according to the method of the present invention, the locally heated wear-resistant material is rapidly cooled and solidified. For cooling, various heat treatments can be designed depending on the components of the wear-resistant part and the specifications of the intended valve train sliding member. For example, simple cooling in the air, cooling in the air using Airbu 0-1 followed by oil or water quenching, or other cooling methods are possible. In some cases, it is also possible to apply other known heat treatment methods, and if necessary, after cooling, cutting, grinding, or other mechanical processing is performed on the wear-resistant parts during the cooling process, so-called mechanical heat treatment. Good too.

Examples of the invention Examples of this invention are described below.

Example 1 - As shown in FIG. 1, a valve lift shaped base material 1 was obtained by cutting ordinary carbon steel S45. On the sliding surface portion 2 of the valve lift shaped base material 1 that comes into contact with a cam (not shown), a second
A concave portion 4 having a shape corresponding to that of the wear-resistant portion material 3 shown in the above was formed.

On the other hand, a wear-resistant part material 3 having the shape shown in FIG. 2 was prepared in the following manner.

Or5%, Mo1%, W 0.1%, Cu 3%, P
Sprayed alloy powder (-100 mesh) consisting of 0.3% Ni, balance Ni and 2% or less impurities, natural black
“□Add 2.8% lead powder (average particle size 10μ) by scuttling,
0.8% zinc stearate as a lubricant
Add and mix. The mixed powder is 20φX5 in a mold press.
+am shape, density 6. Oa/cs3 was molded to obtain a wear-resistant part material 3.

Next, as shown in FIG. 13, the FA wear part material 3 was fitted into the recess 4 of the valve lift shaped base material 1. In this state, the wear-resistant part material 3 was locally heated in a protective atmosphere using a T I GW contact torch (not shown). The heating temperature is approximately 120°C, which is higher than the liquid phase generation temperature of the raw material powder used.
The temperature was 0°C.

Thereafter, the heated part was quenched by air blowing to obtain a valve lifter rough material 5 in which a Ni-based sintered alloy 3a was fusion-welded to the sliding surface part 2 of the valve lift-shaped base material 1, as shown in FIG. A portion of the valve lift shape 5toi of the valve lifter rough material 5 was heat-treated and the whole was machined to obtain a completed valve lifter 5a shown in FIG.

The valve lifter completed product 5a obtained above was installed in a 214-cylinder OHV engine, and the acceleration condition was 1000 rpm.
A pitting resistance evaluation test was conducted for 500 hours.

Example 2 As shown in FIGS. 6 and 7, a rocker arm-shaped base material 6 was obtained by forging SCr 20 steel. A recess 9 having a shape corresponding to the M* ring part material 8 shown in FIG. 8 was formed in the emotional surface part 7 of the rocker arm-shaped base material 6 that comes into contact with a cam (not shown).

On the other hand, a wear-resistant part material 8 having the shape shown in FIG. 8 was prepared in the following manner.

Or5%, Mo5%, wio%, ■5%, Nb0. S%
, 0010%, Ta0.1%, B 001%, C1,5
%, Fe 3%, Si 1%, Mrl 0.4%, balance N
Sprayed alloy powder (-
100 mesh), 1% of Graph7ite and 1.0% of n8I agent were added and mixed by final precipitation. The mixed powder was molded in the same manner as in Example 1, thereby creating a wear-resistant part material 8.

Next, the wear-resistant portion material 8 was fitted into the recess 9 of the rocker arm-shaped base material 6. In that state, the wear-resistant part material 10
1 locally in a protective atmosphere by a laser beam.
It was heated to 220°C.

Thereafter, the heated part was quenched with air blow to obtain a rocker arm rough material in which an iron-based sintered alloy formed by sintering the wear-resistant part material 8 was fused to the sliding surface part 7 of the rocker arm-shaped base material 6. . Rocker arm shape base material 6 of the rocker arm rough material
The parts were subjected to necessary heat treatment, and the necessary parts of the whole were machined to obtain a finished rocker arm 11 shown in FIG. 9.

The finished rocker arm 11 obtained above is 214
Attached to cylinder OHC engine, 2000 rpm under acceleration conditions
A scuffing resistance evaluation test was conducted for m x 500 hours.

Example 3 As shown in Figure 1, ordinary carbon! 14345 was cut to obtain a valve lift shaped base material 1. A recess 4 having a shape corresponding to the wear-resistant member material 3 shown in FIG. 2 was formed in the sliding surface 2 of the valve lift-shaped base material 1 that comes into contact with a cam (not shown). On the other hand, a wear-resistant part material 3 having the shape shown in FIG. 2 was prepared in the following manner.

Cr2O%, MOl%, ■ 8%, W 5%, l”e
Sprayed alloy powder (-
100 pieces), natural graphite seedlings (average particle size 10 grains)
was added in an amount of 2.8% by scuttling, and 0.8% of zinc stearate was added as a lubricant by final precipitation. The mixed powder was pressed into a shape of 20φ x 5mm with a density of 6. Og
/cm3, thereby obtaining a wear-resistant part material 3.

Next, as shown in FIG. 3, the wear-resistant part material 3 was fitted into the recess 4 of the valve lift shaped base material 1. In this state, the wear-resistant part material 3 was locally heated by a plasma beam in a protective atmosphere.

The heating concentration is higher than the liquid phase generation temperature of the raw material powder used1.
The temperature was 230°C.

Thereafter, the heated part was quenched with air bubbles to obtain a valve lifter rough material 5 in which an iron-based sintered alloy 3a was fused to the sliding surface part 2 of the valve lift-shaped base material 1, as shown in FIG. That valve lifter rough material 5! A portion of the help lift shaped base material was heat treated and the whole was machined to obtain a completed valve lifter product 5a shown in FIG.

The valve lifter completed product 5a obtained above was installed in a 214-cylinder OHV engine, and under acceleration conditions 1 ooorp
A pitting resistance evaluation test was conducted for 500 hours.

According to the results of the evaluation tests for each of the Examples above, it was confirmed that the valve lifters of Examples 1 and 3 had extremely high pitting resistance. Furthermore, the rocker arm of Example 2 was confirmed to have extremely high scuffing resistance.

Effects of the Invention As described above, according to the valve train sliding member of the first invention of this application, the average particle size is 1 to 5 in the N1 or 00 matrix.
Hard phase with hardness Hv 600-1800 at 0JJll is 5
Ni or C uniformly fractionated with an area ratio of ~80%
Since the o-based sintered alloy is integrally fusion-welded to the iron-based base material,
It is possible to obtain an extremely dense and abrasive valve train sliding member. Further, according to the method for manufacturing a valve train sliding member according to the second invention of this application, a wear-resistant member material consisting of a green compact or pre-sintered powder of N1 or Co-based alloy powder is formed on an iron-based base material. Since it is sintered and bonded to the iron-based base material, the valve train sliding member of the first invention can be manufactured efficiently and at low cost, and in particular, there is a wide range of selection of materials used as alloy powder. It has the advantage of being spacious.

[Brief explanation of drawings]

Figures 1 to 5 are diagrams showing the steps of an embodiment of the second invention of this question, in which Figure 1 is a sectional view of the valve lift shaped base material, Figure 2 is a sectional view of the wear-resistant part material, FIG. 3 is a sectional view showing a state in which the wear-resistant part material is assembled on a valve lift-shaped base material, and FIG. 4 is a sectional view showing a state in which the wear-resistant part material is sintered on the valve lift-shaped base material. The fifth factor is a cross-sectional view of the completed valve lift product. 6 to 9 are diagrams showing the steps of another embodiment of the second invention of this application, in which FIG. 6 is a cross-sectional view of the rocker arm-shaped base material, and FIG. 7 is a diagram showing the steps in FIGS. A sectional view, FIG. 8 is a perspective view of the wear-resistant part material, and FIG. 9 is a perspective view of the completed rocker arm. 1... Valve lifter shape material, 3... Wear-resistant part material, 3a... Iron-based sintered alloy, 5a... Valve lifter finished product, 6... Rocker arm shape material, 8.
... Wear-resistant part material, 11... Completed rocker arm product. Applicant Toyota Motor Corporation Agent Patent Attorney Yutaka 1) Hisashi Take (and 1 other person) Figure 1 Figure 2 Figure 3 Figure 4

Claims (6)

[Claims] (1) Average particle size 1 to 5 in Ni or Co matrix
Ni or Co in which a hard phase with a hardness of 0 μm and Hv 600 to 1800 is uniformly dispersed at an area ratio of 5 to 80%.
A valve train sliding member characterized in that a sintered alloy is integrally fused to an iron base material. (2) A wear-resistant part material made of a green compact or pre-sintered body of Ni-based or Co-based alloy powder is installed on an iron-based base material, and the wear-resistant part material installed on the iron-based base material is Liquid phase ratio is 20
1. A method for producing a sliding member for a valve train, characterized by locally heating the liquid phase generation temperature or higher to a temperature of 80% or higher, and then rapidly cooling and solidifying the material. (3) The valve train according to claim 1, wherein the Ni or Co-based sintered alloy has a residual porosity of 2% or less and an apparent hardness of Hv450 to 1000. System sliding members. (4) the Ni-based sintered alloy contains 1.0 to 40% Cr (weight ratio, the same applies hereinafter), and 0.1 to 5.0% Mo;
W0.5-10%, V0.1-6.0%, Nb0.05
-3.0%, Ta0.05-1.5%, and the balance is C0.3-3.5% and Ni.
The valve train sliding member according to claim 1 or 3, characterized in that the content of impurities is 2% or less. (5) The Ni-based sintered alloy has Cu1.0 to 5.0%,
Fe1.0-20%, Co1.0-20%, Si0.1
~1.5%, Mn0.1~1.5%, P0.1~0.8
%, B0.01 to 0.5%, or B0.01 to 0.5%. (6) The Co-based sintered alloy contains 2.0 to 40% Cr, and 0.1 to 5.0% Mo, 0.5 to 10% W, and V
0.1-6.0%, Nb0.05-3.0%, Ta0.
Contains one or more of 05 to 1.5%,
The valve train sliding member according to claim 1 or 3, wherein the balance is 0.3 to 3.5% of C, Co, and 2% or less of impurities.