JPS6160869A - Hot chamber - Google Patents

Abstract

PURPOSE:To provide a hot chamber having excellent durability by constituting said chamber of the ferrous sintered material dispersed and incorporated with hard particles at an adequate area ratio by diffusing and solutionizing the periphery thereof partially into matrix and ferrous sintered material having good heat conductivity. CONSTITUTION:The 1st member including the part to contact slidingly with the valve on a combustion side of the hot chamber for an internal-combustion engine consists of the ferrous sintered material which contains the hard particles having>=500 Hv at 3-30% area ratio and in which the components of such hard particles are dispersed by partially diffusing and solutionizing the same at the periphery of the particles into the matrix consisting mainly of pearlite. The 2nd member corresponding to the cylinder head except the above consists of the ferrous sintered material having at least >=0.01Cal/cm.sec. deg.C heat conduc tivity and having the heat conductivity equal to or higher than the heat conduc tivity of the above-mentioned 1st member. The above-mentioned 1st member consists preferably of 0.8-35wt% C, 1.0-10.0% Cr, 0.2-6.0% Ni, 1.0-10.0% Mo, 1.0-15.0% Co and the balance substantially Fe and the 2nd member consists of 0.8-3.0% C, 0.5-5.0% Cr, 1.0-5.0% Cu and the balance Fe.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an integrated combustion chamber in which a cylinder head and an intake/exhaust valve seat of an internal combustion engine are integrated, that is, a so-called hot chamber.

In recent years, internal combustion engines have become increasingly high-output while satisfying social demands such as exhaust gas regulations and reduced fuel consumption.As a result, the heat load around the combustion chamber, which is directly exposed to combustion gas, is high. It has become to.

(Prior art) Currently, in general internal combustion engines, a valve seat made of sintered material or VP steel is press-fitted or cast into a cylinder head made of FC or Alg. (If the cylinder head becomes severely deformed due to heat, the sealing performance of the combustion gas between the cylinder head and the valve seat will deteriorate, and the valve seat or valve will wear abnormally with the cylinder head, causing a risk of an accident. Therefore, in some internal combustion engines, the combustion chamber is made spherical and an integrated hot chamber is used to prevent deformation, but in order to improve the wear resistance of the valve seat part, high alloy When vP steel is applied to a hot chamber, cavities and other defects appear in the hot chamber, which has a spherical shape, which is a complex shape for casting, due to the poor castability of high-alloy cast steel.

(Problems to be Solved by the Invention) In view of the above, the present invention provides a hot chamber with excellent durability for use in high-load engines.

In particular, the present invention uses sintered material in the hot chamber to reduce blowholes and other internal defects, and uses sintered material in a composite structure to fully satisfy the different properties required for the cylinder head and valve seat. This provides a hot chamber that allows for

(Means for Solving the Problems) The hot chamber according to the present invention has a first member (al) containing hard particles of Iv500 or more that exceeds 3% in area ratio and includes a portion that comes into sliding contact with a valve on the combustion chamber side. % or less, and the components of the hard particles are partially dispersed as a solid solution in a matrix mainly composed of pearlite around the hard particles, and the first member The second member (b) corresponding to the cylinder head other than (a) has a thermal conductivity of at least 0.01 cal/a
It is characterized in that it is made of an iron-based sintered material having a thermal conductivity equal to or higher than the thermal conductivity of the first member (a) in a range of ++, sec, 'c or more.

(Function) The part (first member (a)) that is in sliding contact with the valve on the combustion chamber side of the hot chamber, which corresponds to the insert valve seat in a general cylinder head, is heated at least 3,000 to 4,000 r.
If pa+ is large, the engine rotates at over 110,000 rpm and is directly exposed to combustion gas, subject to severe knocking and sliding wear. The first member (a) that comes into sliding contact with the valve is required to have both heat resistance and wear resistance. In the present invention, knocking and sliding wear is dealt with by the first member (al) having a structure in which hard particles are dispersed in a matrix mainly made of pearlite.

If the hardness of the hard particles is less than Hv 500 or less than 3% in terms of area ratio, the effect of improving wear resistance cannot be obtained.On the other hand, if it exceeds 30%, material embrittlement and decrease in workability may occur. The harm will increase. Further, when the components of the hard particles are partially diffused and solid-solved around the hard particles, the bonding characteristics between the hard particles and the matrix are improved, and the Beary action between the hard particles and the matrix causes the first member (a) to form a solid solution. The wear resistance is further improved.

Next, the function of the hot chamber is to provide wear resistance against sliding contact between the first member (8) and the valve, and to dissipate combustion heat to the outside through the second member (b) corresponding to the cylinder head. is required. This function is determined by the thermal characteristics of the hot chamber in the portion other than the first member (a) that comes into sliding contact with the bulb.

If the thermal conductivity of the second member (bl is lower than the thermal conductivity of the first member (al), the second member (1)) to the first member (a
), and the first member (a) is exposed to high temperatures, resulting in thermal deformation, softening, etc. Therefore, the portion of the hot chamber other than the first member (al) that comes into sliding contact with the bulb should have a thermal conductivity equal to or higher than that of the first member (a) that comes into sliding contact with the bulb.Furthermore, the second member (' The thermal conductivity of b) is 0.01ca
l/aI1. iec, 'C, the second member (
Heat dissipation through bl becomes insufficient. Therefore, the second member (
The thermal conductivity of b) is 0.01cal/ai, se
c, 'C or higher.

1 to 3 show examples of hot chambers each having two (11) intake ports and two (11) exhaust ports.

FIG. 2 is a plan view of the hot chamber, with la, l
b indicates an intake boat, and 2a and 2b indicate exhaust ports.

3 is a plug seat.

The preferred composition of the first member is C0.8 to 3.5 in terms of weight ratio.
%, Cr 1.0-10.0%, Ni 0.2-6
．． 0%, M.

i, o ~io, o%, Go 1.0~15.0%2
The remainder consists of Fe and impurities. The first member (
If the C content in Al is less than 0.8%, ferrite will precipitate in the matrix and the wear resistance will decrease;
If the content exceeds 3.5%, free graphite remains and strength decreases, and Cr, Mo and C combine to form coarse carbides.
．． If it is less than 0%, there will be few carbides formed by combining with C, resulting in insufficient wear resistance, and Cr, ?
The amount of solid solution of Io in the matrix is also insufficient, resulting in insufficient heat resistance. On the other hand, if the content of Cr and hO exceeds 10%, carbides become coarse and the strength and workability decrease.
If Ni exceeds 660% or Go exceeds 15.0%, the heat resistance of the matrix becomes insufficient.
If the amount exceeds , the effect reaches a ceiling and the economical efficiency decreases considering the amount added.

In the second member), the preferred composition is G 0.8 to
3.0%, Cr 0.5-5.0%, Cu 1.0-5
．． 0%, and the balance is Fe and impurities. In the second member (b), if the C content is less than 0.8%, ferrite will precipitate in the matrix and the wear resistance will decrease, while if the C content exceeds 3.0%, free graphite will remain. If the Cr content is less than 0.5%, the amount of solid solution of Cr in the matrix will decrease, resulting in a lack of heat resistance, while if the Cr content exceeds 5.0%, coarse carbides will be formed. It precipitates and causes a decrease in strength as well as an impediment to thermal conductivity. If the Cu content is less than 1.0%, sufficient strength cannot be obtained and no improvement in thermal conductivity can be expected.
When the u content exceeds 5.0%, undissolved Cu remains and strength decreases.

As shown in FIG. 1 (cross-sectional view taken along line II in FIG. 2) and FIG. 3 (cross-sectional view taken along line mm in FIG. 2), valves ( (not shown) is in contact with the first member fat, and non-contact parts are in contact with the second member fat.
Consists of member (b). Since the first member (a) and the second member (b) are manufactured by sintering accompanied by compaction, the first member (a) and the second member (inside) are respectively cored to facilitate molding. It is desirable that the body and covering be placed inside and outside as shown.

Both the first member (, 11) and the second member (b) of the hot chamber of the present invention contain pores specific to the sintering method.

Since these pores are usually around 10%, they do not cause combustion gas leakage.However, since pores are inconvenient in terms of heat conduction, the first member (a) is made of a known Cu alloy for infiltration. And it is preferable to infiltrate and seal the second member (b). By infiltration, the Cu content of the second bamboo material tb> is 10%.
When the thermal conductivity becomes 0.1cal/as
, sec, 'C or higher (Example) Next, the present invention will be explained in detail using experimental examples.

Weight ratio: 20% Cr, 20% Mo, 34% Co, N
Alloy powder containing 8% i, 15% Fe, and 3% other (
-150 mesh), commercially available Fe(:r powder (-100
mesh), FeMo powder (-100 mesh), reduced iron powder (-100 mesh), and graphite powder (10I1m)
Hot chambers of Example 1.2.3 and Comparative Examples 1 and 2 having the component compositions shown in Table 1 were manufactured using two molding and sintering process conditions normally used in powder metallurgy. However, the pressure in the powder molding process is 5-6
ton/ca! The sintering conditions were 1130° C. for 50 minutes in a decomposed ammonia gas atmosphere.

The thermal conductivity of the first member (Al's y! quality particle hardness, hard particle content and thermal conductivity, and further in the second member) that comes into sliding contact with the bulb of the obtained hot chamber is determined by the first
Shown in the table.

The hot chambers of Examples and Comparative Examples thus obtained were subjected to endurance operation of 100) 1r at 9000 rpm x 4/4 using a 500 call cylinder gasoline engine. The wear amount of the first member (al) after operation is also listed in Table 1.

As shown in Margin Comparative Example 1 below, the first member that comes into sliding contact with the valve +al
When the content of hard particles is small, wear progresses quickly, and even when the thermal conductivity of the second member (b) is lower than the first member + al (comparative example 2), heat dissipation is hindered. Wear of the first member (aJ progresses. In contrast, Examples 1 to 3
has excellent durability as a hot chamber.

(Effects) The hot chamber of the present invention has excellent durability for use in high-output internal combustion engines. When the hot chamber of the present invention is compared to a cast hot chamber, it has fewer internal defects and each member (a), ( (b) adapts the properties to the desired properties and outperforms the casting pot chamber in overall properties;

[Brief explanation of drawings]

1 is a sectional view of FIG. 2 showing an embodiment of the hot chamber, FIG. 2 is a plan view of the hot chamber, and FIG. 3 is a sectional view of FIG. 2. a - first member, b - second member, la, lb - intake boat, 2a, 2b - exhaust boat, 3 - plug seat.

Claims (1)

[Claims] 1. In an integrated combustion chamber (hereinafter referred to as a hot chamber) that integrates a cylinder head and an intake/exhaust valve seat, a first member (a) that includes a portion that comes into sliding contact with a valve on the combustion chamber side. is H
Contains more than 3% and less than 30% of hard particles with v500 or more in terms of area ratio, and the components of the hard particles are partially diffused and dissolved in a solid solution around the hard particles in a matrix mainly made of pearlite. The second member (b) corresponding to the cylinder head other than the first member (a) has a thermal conductivity of at least 0.01 cal.
/cm. sec. A hot chamber characterized in that it is made of an iron-based sintered material having a thermal conductivity equal to or higher than that of the first member (a) at temperatures above .degree. 2. The first member has a weight ratio of C0.8 to 3.5%, Cr1.
0~10.0%, Ni0.2~6.0%, Mo1.0~
10.0%, Co 1.0-15.0%, the balance being Fe and impurities, and the second member has a weight ratio of at least 0.8-3.0% C, 0.5-5% Cr. 0%, Cu1
．． The hot chamber according to claim 1, having a composition containing 0 to 5.0% of Fe, with the remainder substantially consisting of Fe. 3. The hot chamber according to claim 1 or 2, which is made of an iron-based sintered material in which the pores inherent in both the first member and the second member are infiltrated and sealed with a Cu-based alloy. .