JPS59222599A - Formation of hard film - Google Patents

Abstract

PURPOSE:To form easily and exactly a hard film only on the head part of a piston which is harged electrostatically to positive and is exposed with only the head part faced downward by hanging the piston and ejecting a soln. contg. sulfuric acid charged electrostatically to negative and air thereto from below. CONSTITUTION:A piston 5 which has a head part 5a faced downward and is covered with masking rubber 6 is suspended in the air of the part upper than the top surface of a soln. contg. sulfuric acid 2 contained in a vessel 1 charged electrostatically to positive. The liquid 2 is vigrously sprayed together with discharging air to the head part 5a by a pump 4 through the hole 3a of an air pile 3 sunk near the top surface of the liquid 2 in this state. As a result, ionization is accelerated and a hard film a of alumite, etc. is quickly and efficiently formed only on the head part 5a. Since the rubber 6 is covered on the piston 5, the film (a) is not formed on the outside circumferential surface and the uniform product is formed without dimensional errors in the outside diameter of the piston 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a piston head h of a diesel engine as an example.
1; relates to a method for forming a hard coating of heat-resistant alumite in a simple and precise manner.

Conventionally, as shown in Fig. 1, a sulfuric acid solution (2) is contained in a tank (1), and charged carbon (8) is inserted into the solution (2) via a rectifier (7). I am forced to do it. Further, the charged piston (5) is lowered (ti) and submerged in the sulfuric acid solution (2) by an appropriate support with the head (5a) facing down. An air pipe (3) connected to a pump (compressed air pump) is placed at the bottom of the sulfuric acid solution (2), and compressed air is blown out through the air hole (3a) to stir the sulfuric acid solution (2). A hard oxide film (abbreviated as hard film) (a) of alumite is formed on the head (5a) of the piston.

With this method, a hard film is likely to form on the outer circumferential surface (5b) of the piston (5), which increases the outer diameter and makes it difficult to achieve smooth piston movement.Also, the efficiency of forming the hard film is not very good. There was a problem.

The present invention has been developed to overcome the above-mentioned difficulties. Hereinafter, the present invention will be described with reference to drawing examples.
The head of the piston (5), which is charged to 0, is suspended with its head facing down, and air is supplied to the air pipe (3) introduced into the sulfuric acid solution (2) through the pump (4). blow 1]
Are you tired of doing this? Stir the liquid (2) and remove the piston head a.
(5a) is covered with a rubber (6) in the form of a hard corrugated film, which is intended to form an alumite coating 11@(a), and the piston head (5a) is placed in the air above the sulfuric acid solution (2). This method of forming a hard film is characterized in that a sulfuric acid solution and air are sprayed onto the head of the device via a downward pump (4) to form a hard film (a).

In the present invention, as shown in FIG. ! Le
The air pipe (3) connected to the pump (4) is connected to the sulfuric acid solution (111).
2) It is installed near the top surface, and when air is blown out through the air hole (3a) through the pump (4), the sulfuric acid solution is also ejected along with the air toward the head of the piston, speeding up ionization and efficiently producing high F. It is possible to create an oxide film on aluminumite that can be heated. In this case, as shown in Figure 3, masking rubber (6)
If the piston (5) is covered and supported by the piston (5), no hard coating (a) will be formed on the outer circumferential surface, so that the outer circumferential dimension can be corrected. For the sulfuric acid solution, a cooling liquid at -4°C is used.

It should be noted that it can be used not only for pistons but also for any machinery or parts that require a hard coating, and any other design changes other than those described in the specification and drawings are free to be made within the scope of the spirit of the present invention. can.

According to the present invention, the head (5
a) Cover the piston (5) with masking rubber (6) on the bottom.
) is suspended and discharged via the pump (4) from the hole (3a) of the rough air pipe (3), which is submerged near the top surface of the sulfuric acid solution (2), to form a hard coating (a) of alumite. .

Since no hard film is formed on the outer circumferential surface of the piston with the masking rubber (6), there is no deviation in the outer diameter of the piston. The product can be made uniformly. Since the method of forming the hard film is simple, it is extremely economical and has many practical benefits.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional method of forming a hard coating on the head of a piston, FIG. 2 is an explanatory diagram of a method of forming a hard coating on the head of a piston according to the present invention, and FIG. FIG. 3 is a front view of the stone covered with masking rubber. a...hard coating, 1...tank, 2...sulfuric acid solution, 3...air pipe, 3a...air hole, 4...pump, 5...
・Piston, 5a...Head, 5b...Outer circumferential surface, 6...
Masking rubber, 7... rectifier, 8... carbon. Patent applicant Chozabe Matsui

Claims (1)

[Claims] A sulfuric acid solution (
2) Suspend the piston (5) charged to (G) with its head downwards, and pour the sulfuric acid solution (
2) A hard alumite coating (a) is formed on the piston head (5a) by blowing out air through the air pipe (3) and stirring the sulfuric acid solution (2). Cover the piston head (5a) with sulfuric acid solution (2
) The sulfuric acid solution and air are blown onto the piston head through the lowering pump (4) into the air on the upper surface of the piston (a).
What to do to form! 1! ? Method for forming a hard film with characteristics 1.