JPH0255809A - Ceramic sliding part and manufacture thereof - Google Patents

Abstract

PURPOSE:To contrive the cost down by connecting by heat a ceramicmade sliding part to a base member metal part, in the case of a tappet in an internal combustion engine. CONSTITUTION:A Cu plate 13 is arranged as a buffer material in a connection surface of a ceramic chip 12, consisting of silicone nitride, thereafter a metal made tappet main unit 11 performs a brazing process for 10 minutes at 925 deg.C in a vacuum continuous furnace. Next the tappet main unit 11 is cooled to 300 deg.C for about 15 minutes in an N2 gas displacement cooling furnace, processing a metal part to be hardened to not less than HRC45. In this way, the cost down can be attained by forming only the necessary part to be made by ceramic.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ceramic sliding component having performance suitable for rocker arms, tappets, etc., and a method for manufacturing the same.

[Conventional technology]

In recent years, there has been an increasing demand for high reliability for sliding parts such as longer engine life, maintenance-free engines, and adoption of EOR for diesel engines. Under these circumstances, research has been conducted to improve wear resistance by composing sliding parts with ceramics, and some of these have been put to practical use in rocker arms (for example, Utility Model No. 60-170006). (see publication)
.

[Problem to be solved by the invention]

However, constructing the entire sliding part with ceramic has problems in terms of strength and cost, and only the minimum necessary sliding part is made of ceramic, but in this case, it is difficult to combine metal and ceramic. However, there was a problem in that when the two were joined, the metal part became dull due to the influence of heat and the hardness decreased.

Generally, sliding parts such as tappets and rocker arms made of high-strength metal have two or more sliding parts, and wear may be a problem in only one of them. Since there are many parts, it may be possible to make only those parts ceramic.

However, due to the bonding process (generally heat bonding using brazing filler metal is used), the hardness of the parts that have not been made into ceramics decreases, and wear of those parts becomes a problem. Countermeasures such as induction hardening after joining became necessary.

However, when the hardened part and the joint part are close to each other, strain during hardening causes a decrease in joint strength, damage to the ceramic, etc., and it is often difficult to avoid these problems.

The present invention aims to improve the above-mentioned problems of the prior art and to provide a ceramic sliding component with improved practicality and a method for manufacturing the same.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for bonding ceramic to at least one sliding part of a sliding part such as a tappet-rocker arm made of a high-strength metal material. At the same time, the hardness of other metal parts is hardened to Rc45 or higher.

[Effect]

The metal material used in the present invention is JIS, 8NCM650
(Oa25~G, 35%, 81a15~155%, Mn
cL'55~α60%, Ni2.5~55%, 0r2
-5~3<5%, MoQ, 5~α7%, balance pe and unavoidable impurities), so-called nickel, chromium, molybdenum (m) or J Engineering El, SKC! 24 (On
, 33-0.45%, 5iOCL15-α55%, Mn
Q, 50-1.00%, N12.5-55, O
r El 5-l 7 s, Mo a 15-α4
%, the balance being Fe and unavoidable impurities υ, such as so-called medium steel), which undergoes simultinsite transformation and hardening when air cooled, is used in the heating temperature range for ceramic bonding.

Under harsh conditions of use, such as in the valve train of an automobile engine, the surface pressure on the sliding parts of the sliding parts is high, so in order for these parts to withstand wear, they must be made of high hardness. According to various test results, HRO4
It was confirmed that it is necessary to set the score to 5 or more.

[Actual example]

Implementation row 1 After vaporizing a metal such as titanium by sputtering on the bonding surface side of a ceramic chip φ20 made of 81, IJ, y), a lifter body made of JIS SNCM 630 y) (hardness HR before bonding process HR(,20) Then, Cu plate ((L
5+e+thickness) due to the difference in thermal expansion coefficient between ceramic and metal υ
Ag-C is used as a buffer material to alleviate the strain stress that occurs.
The U brazing material (72% Ag, 28% OU) was subjected to brazing treatment at 925° C. for 10 minutes in a vacuum continuous furnace. Thereafter, it was cooled to 300° C. for about 15 minutes in a N2 Ganu displacement cooling furnace. The hardness of the metal part of the lid is HR
It was C47.

Example 2 S114 Bonding of a good ceramic chip [After cleaning the fi, a Ni plate (15
A waxing process was carried out at 900° C. for 10 minutes in the same vacuum continuous furnace as in Example 1, using a material (thickness: m) as a buffer material. Thereafter, it was cooled to 300° C. in about 20 minutes in a gas 1i dust cooling furnace. The hardness of the metal part of the /ζ valve bridge is HR
c 56.

Comparison column: Ceramic chips were bonded using tappets made of S400 heat-treated steel (using the same method as in Example 1), but the metal part hardness of the obtained product was about HRO5, and it was in an annealed state. Met.

These are summarized in Table 1.

tappet ceramic chip buffer board Bush rod per 9 sides Cam contact surface valve bridge ceramic chip buffer board Rocker arm contact surface Valve end contact surface guide

Claims (1)

[Claims] (i) A plurality of sliding parts are provided, at least one sliding part of which is made of a ceramic material heat-bonded to a base metal, and the metal part other than the ceramic is H_R_C4.
Ceramic sliding parts hardened to 5 or higher. (ii) In the manufacture of a sliding part that has two or more sliding parts, at least one of which is made of ceramic, and the ceramic is heat-bonded to the metal forming the remaining sliding parts, The metal forming the sliding part is made of a steel material that undergoes martensitic transformation when cooled in air, and the metal part forming the sliding part is hardened to H_R_C45 or higher using heating for joining. Method for manufacturing ceramic sliding parts.