JPS6037191B2 - Surface treatment method for internal combustion engine tappets - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface treatment method for a plate for an internal combustion engine for surface-treating the sliding surface of a plate for sliding contact with a camshaft.

Generally, the sliding surface of the cam shaft used in internal combustion engines is surface-treated, and the sliding surface of the cam shaft, which is formed by chill casting, is treated with a manganese phosphate chemical conversion treatment. Many are used with loop light processing.

Also, when processing the loop light, the processing side of the evening bed should be
After polishing to a level below the peak Rz, the surface is treated by immersing it in a treatment solution, but the phosphoric acid contained in the treatment solution corrodes the base material of the treated surface (mainly pearlite or martensitic composition), causing bits to deteriorate. At the same time, the cementite remains as it is without being corroded, so the cross section of the treated surface becomes as shown in FIG. Therefore, when the treated layer a is worn out during operation, the cementite b remaining in the treated layer a is exposed, causing premature wear of the other camshaft, and the cementite falling off and causing the sliding of the bed itself. The surface may also be damaged, or oil may run out, causing problems such as staining. This invention was made for the purpose of improving such defects.
Provided is a surface treatment method for a cover for an internal combustion engine in which loop light treatment is applied to the sliding surface of the cover while minimizing the etch pitch generated during surface treatment, thereby increasing the durability of the treated surface. It is intended to increase the

The present invention will be explained below with reference to the drawing shown in FIG.

First, the treated surface of the sheet formed by chill casting is polished to 1 french Rz or less, and then placed in an organic solvent such as Drysol to degrease the rust-preventing oil and the like adhering to the sheet. Next, it is washed with water that has been neutralized by putting it into an alkaline solution at a temperature of 65 to 70° C. for about 5 minutes, and then using Nippon Parker's Percolene VMO. The treated surface is immersed in a 3% aqueous solution for 0.5 minutes or more to condition the surface. Next, the metallic iron is immersed in acid with a phosphoric acid concentration of 4 to 6 points and a total acidity (total of phosphoric acid and monomanganese phosphate) of 29 to 31 points, so that the iron content becomes 500 to 250 pm. After immersing 7 to 1 pieces in a treatment solution with an adjusted temperature of 96 to 9900 degrees (e.g. Nippon Par Co., Ltd.'s Vercolubrite IA, IAM, etc.), the pieces taken out from the treatment solution are washed with water and rust-proofed. to complete surface treatment. The concentration of acid is 0.1N
It is expressed as the neutralization titer using an aqueous sodium hydroxide solution (NaOH) of (normality), and the amount of NaOH required for neutralization (
cc) is displayed as a point. By the way, sodium hydroxide lcc is equivalent to 1 point. In addition, when the acid concentration exceeds the upper limit of the above range, the proportion of etch bits increases and wear resistance decreases, and conversely, when the acid concentration decreases, the proportion of etch bits decreases, but oil retention decreases and seizure occurs. Therefore, it is appropriate for the acid concentration to be within the above range.

The etch bit ratio on the treated surface of the obtained evening plate was 10 to 28%, 1/5 to 1/5, compared to the conventional one (50 to 70%).
It is less than 1/3, and as a result of testing this on a bench test, the second
The result is shown in the figure.

That is, curve A indicates the etched bit ratio of the treated surface of the sheet treated by the method of the present invention of 10 to 28%. Curve B is a sample obtained by conventional loop light processing, and the etch bit ratio on the treated surface is 50 to 70%, indicating that the amount of wear is significantly greater than that of the surface treated by the method of this invention. it is obvious. The C curve is shown for reference in the case of a sheet without surface treatment.
The test was stopped midway due to galling. As described in detail above, this method of the invention applies rubrite treatment to the sliding surface of the slide while suppressing the generation of etch bits. Since there are no blinds that accelerate wear or cause seizures due to lack of oil, the durability of the treated surface can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a treated surface obtained by a conventional surface treatment method, and FIG. 2 is a diagram showing a comparison between the wear resistance of the treated surface obtained by the method of the present invention and that of a conventional surface treatment method. Figure 1 Figure 2

Claims (1)

[Claims] 1 After washing and degreasing the tappet formed by chill casting with water, the treated surface is surface-conditioned, and then it is treated with a phosphoric acid concentration of 4 to 6.
At a temperature of 96 points, metal iron is immersed in an acid with a total acidity (sum of phosphoric acid and monomanganese phosphate) of 29 to 31 points and adjusted so that the iron content is 500 to 2,500 ppm.
A method for surface treatment of a tappet for an internal combustion engine, characterized in that the surface treatment is carried out by immersing the tappet in a treatment liquid at ~99°C.