JPH09303196A - Surface treating method for cylinder block inner surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform surface treatment of only the inner surface of a cylinder when surface treatment is applied on the inner surface of the cylinder of a two-cycle engine. SOLUTION: When nickel composite plating is applied on the cylinder inner surface Wa of a cylinder block W made of aluminum, at a series process from pretreatment to plating treatment, an air balloon B is inflated in a state to be adhered on the cylinder inner surface Wa to close the opening parts of suction and exhaust holes P and Q and the passage of the suction and exhaust holes P and Q is filled with foamed resin O for sealing. With this state, treatment liquid is circulated over the cylinder inner surface to effect surface treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a surface treatment method for plating the inner surface of a cylinder block of a two-cycle engine used in an engine such as a motorcycle.

[0002]

2. Description of the Related Art In recent years, aluminum cylinder blocks have become widespread due to demands for weight reduction of automobile engines and exhaust gas regulations, and wear resistance, scuff resistance, and seizure resistance of the inner surface of a cylinder on which a piston slides. For this reason, a technique has been developed for performing plating treatment such as nickel composite plating on the inner surface of the cylinder. For example, in Japanese Utility Model No. 61-143598,
A technique is disclosed in which a treatment liquid is circulated by sealing an inner space of a cylinder, and a series of surface treatments from a pretreatment to a plating treatment to a posttreatment on the inner surface of the cylinder are continuously performed.

On the other hand, in the case of a two-cycle engine, since the intake / exhaust holes are opened on the inner surface of the cylinder, it is difficult to partially treat the surface of the cylinder only. The entire surface is treated by dipping. That is, for example, the cylinder block is suspended by a suspending tool and made movable by a conveyor, for example, an alkali degreasing step, an etching step, an acid activation step,
The conveyor is moved in the order of the zinc replacement step, the composite plating step, the chemical treatment step, etc., the cylinder block is moved up and down, and the cylinder block is immersed in the processing tank for processing.

[0004]

However, in the method of treating by immersing the entire cylinder block in this way, surface treatment is performed up to unnecessary points, and for example, the wear of the cutting tool is accelerated in the subsequent machining or the like, A large amount of the processing liquid in the upstream processing tank was carried into the downstream processing tank, which shortened the service life of the processing liquid, and the production equipment increased in size.

Therefore, in the case of a cylinder block of a two-cycle engine as well, as in the cylinder block of a four-cycle engine, there has been a demand for a method of partially surface-treating only the inner surface of the cylinder.

[0006]

In order to solve the above-mentioned problems, the present invention provides a method for surface-treating an inner surface of a cylinder block of a two-cycle engine according to claim 1, wherein an opening opening toward the inner surface of the cylinder is provided. After masking, only the inner surface of the cylinder was partially surface-treated.

In this way, the inner space is hermetically sealed by masking the openings such as the suction and exhaust holes that open on the inner surface of the cylinder, and the treatment liquid is introduced into this hermetically sealed space to partially surface-treat the inner surface of the cylinder.

In the second aspect, the surface treatment is a series of steps from the pretreatment to the plating treatment. Then, with the opening masked, for example, the cylinder inner space is sealed in each step, and the sealed space is filled with, for example, an alkaline degreasing treatment liquid, an etching treatment liquid, an acid activation treatment liquid, a zinc substitution treatment liquid, a composite plating treatment liquid, etc. The treatment liquid is sequentially circulated to continuously perform surface treatment.

In the third aspect of the present invention, the masking is performed by fitting the fitting member in close contact with the inner surface of the cylinder and then packing the sealing member in the passage leading to the opening of the inner surface of the cylinder. At this time, if the fitting member closes the opening to the cylinder surface and the sealing member is pushed toward the opening, the sealing member can be neatly packed up to the opening.

According to a fourth aspect, the fitting member is a balloon,
Further, the sealing member is made of foamed resin. Then, for example, if the deflated balloon is inserted into the cylinder internal space and inflated, the work is extremely easy. Also, if you inflate the balloon strongly,
Since the balloon enters the passage by biting into the passage a little, when packing the sealing member, the sealing member does not enter the inner surface of the cylinder near the opening and does not adversely affect the inner surface treatment. Surface treatment can be done reliably. Further, if the sealing member to be packed in the passage is made of foamed resin, the packing work is facilitated, and the foamed resin is gasified or solidified into a small size when heated in, for example, the drying step after the surface treatment. It is possible and easy to discharge.

[0011]

Embodiments of the present invention will be described with reference to the accompanying drawings. Here, FIG. 1 is a process diagram when plating the inner surface of the cylinder of the cylinder block, FIG.
FIG. 4 is an explanatory view showing a masking procedure of an opening portion opened on the inner surface of the cylinder, FIG. 3 is a state diagram in which the masking is performed and a plating process is performed, and FIG. 4 is an apparatus configuration diagram in the plating process.

The surface treatment method of the present invention is applied, for example, when the inner surface of a cylinder of an aluminum cylinder block of a two-cycle engine of a motorcycle is plated with nickel composite plating or the like. The outline consists of a pretreatment process and a plating process. And
In the pretreatment, after removing oils and fats such as cutting oil adhering to the plated surface in a degreasing step, the surface is roughened by an etching step, and a base treatment is performed by a zinc replacement step or the like.

An example of the treatment method of such a surface treatment step is shown in FIG.
As shown in (b), the oil / fat a such as cutting oil adhering to the treated surface of the Al base material containing primary crystal Si is removed by an alkali degreasing step, and then, as shown in (c), by alkali etching. After part of the aluminum is melted and the Si is surely exposed, Si is melted by acid etching to roughen the surface as shown in (d).

Thereafter, as shown in (e) to (g), the first zinc substitution and the second zinc substitution are carried out to form a zinc coating layer b on the surface.
To improve the adhesion between the aluminum substrate and the plating.
Then, after the pretreatment is performed in this manner, a nickel composite plating layer c is formed as shown in (h).

In each of the treatment steps described above, the surface treatment of the two-cycle engine cylinder block is conventionally performed by suspending the cylinder block with a conveyor hanger or the like, and soaking the entire cylinder block in each treatment liquid by a so-called dipping method. Although the whole surface of the cylinder block is treated while being immersed, in the present invention, the surface treatment is limited to the inner surface of the cylinder.

That is, as shown in FIG. 2, in the cylinder inner surface Wa of the cylinder block W, an intake hole P and an exhaust hole Q are formed.
However, conventionally, it was not possible to introduce the processing liquid only into the inside of the cylinder because of the intake hole P and the exhaust hole Q. Therefore, according to the present invention, as shown in FIG. 2, a balloon B as a fitting member is inserted into the cylinder inner surface Wa and inflated to close the openings of the intake / exhaust holes P and Q to the inner surface Wa, thereby sucking / exhausting. A foamed resin O as a sealing member is packed in the passage of the holes P and Q.

When the balloon is deflated and withdrawn, the liquid does not leak from the intake / exhaust holes P and Q even if the processing liquid is introduced into the cylinder, and only the cylinder inner surface Wa can be surface-treated. I can.

Here, the limited surface treatment procedure of the inner surface Wa of the cylinder is a known technique, for example, in Japanese Patent Laid-Open No. 61-143598, but when briefly explained, for example, as shown in FIG. The cylinder block W is mounted on the mounting table 2 which is positioned on the mounting table 2 and the cylinder block W.
The lower surface is sealed, and the upper surface of the cylinder block W is pressed and sealed by the vertically movable sealing member 4 of the cylinder unit 3 mounted on the upper portion of the base 1.

On the other hand, the mounting table 2 is provided with a processing liquid passage 2a communicating with the inside of the cylinder of the cylinder block W, and the processing liquid supply passage 5 is provided on the side of the processing liquid passage 2a.
Is connected, and the processing liquid discharge passage 6 is connected to the lower side. And, in the middle of the processing liquid supply passage 5,
A pump 7 is connected, and a treatment liquid tank 8 is provided at the extending end portions of the treatment liquid supply passage 5 and the treatment liquid discharge passage 6.

The apparatus configuration as described above is substantially the same in each step from the pretreatment step to the plating step, but in the plating step, as shown in FIG. And a cylindrical anode 9 that is inserted through the cylinder. A DC electric circuit (not shown) is provided between the anode 9 and the cylinder block W, and the cylinder block W side serves as a cathode.

Therefore, the cylinder block W is mounted on the mounting table 2
By mounting on top and pressing the upper surface with the sealing member 4, the internal space of the cylinder and the processing liquid passage 2a communicate and are sealed. Then, by operating the pump 7 to circulate the treatment liquid 10 and treating the cylinder inner surface Wa, finally, as shown in FIG. 3, the plating layer c can be formed only on the cylinder inner surface Wa. .

By the way, after a series of plating treatments is finished, the plate is heated and dried. At the time of this heating, the intake / exhaust holes P,
The foamed resin O packed in Q is solidified into a small size and automatically discharged.

Further, since the fitting member is a balloon, the openings of the intake / exhaust holes P and Q can be reliably shielded, and if the balloon is inflated strongly, a part of the balloon will be absorbed. There is no fear that the foamed resin O will enter the exhaust holes P and Q with a little bit of it, and the foamed resin O will enter the cylinder inner surface Wa to adversely affect plating defects.

By the way, FIG. 5 shows an example of a structure in which the inner surfaces of the two cylinder blocks W, W are simultaneously surface-treated. That is, in this case, the two cylinder blocks W, W are turned upside down and stacked vertically to form the clamp plate 11.
After vertically sandwiching and fixing with a and 11b, it is placed on the mounting table 12 and pressed down by the sealing member 14 from above to connect the processing liquid passage 14a of the sealing member 14 and the cylinder internal space, A perforating plate 13 is interposed between the processing liquid passage 12a of the mounting table 12 below and the internal space of the cylinder so that they are communicated with each other through a plurality of holes 13a. Then, the solid rod-shaped electrode 1 erected at the center of the punching machine 13
5 is exposed to the internal space of the cylinder.

Then, the pump 7 is operated to operate the sealing member 1.
Processing liquid 1 from the processing liquid passage 14a
0 is introduced, the processing solution 10 is returned from the holes 13a of the perforated plate 13 through the processing solution passage 12a of the mounting table 12 to the processing solution tank 8 and processed while being circulated. And in this case, it can be processed more efficiently. If a solid rod-shaped member similar to the anode 15 is used in the surface treatment process other than the plating process, the amount of the treatment liquid 10 circulating in the cylinder block W can be reduced.

[0026]

As described above, according to the present invention, in the method of surface-treating the cylinder inner surface of the cylinder block of the two-cycle engine, after masking the opening opening toward the cylinder inner surface, only the cylinder inner surface is partially covered. Since the surface treatment is performed, the treatment liquid is not contaminated as compared with the so-called soaking method, and the life of the treatment liquid can be extended. Moreover, even if the production is increased, the equipment can be downsized. Further, since the balloon is fitted and sealed with the foamed resin when masking, the cylinder resin inner surface can be surface-treated easily and reliably for the packing and discharging of the foamed resin.

[Brief description of drawings]

FIG. 1 is a process diagram for surface-treating an inner surface of a cylinder of a cylinder block.

FIG. 2 is an explanatory view showing a masking procedure of an opening portion that opens on the inner surface of the cylinder.

[Figure 3] State diagram of masking and plating

FIG. 4 is a device configuration diagram in a surface treatment process.

FIG. 5 is an apparatus configuration diagram in the case of simultaneously processing the inner surfaces of two cylinder blocks.

[Explanation of symbols]

B ... Balloon, O ... Foamed resin, W ... Cylinder block, Wa
... Cylinder inner surface, P ... Intake hole, Q ... Exhaust hole.

Claims (4)

[Claims] 1. A method of surface-treating an inner surface of a cylinder block of a two-cycle engine, which comprises masking an opening opening toward the inner surface of the cylinder and then partially surface-treating only the inner surface of the cylinder. The surface treatment method for the inner surface of the cylinder block. 2. The surface treatment method according to claim 1, wherein the surface treatment is a series of steps from pre-plating treatment to plating treatment. 3. The surface treatment method according to claim 1, wherein the masking is hermetically sealed in a passage leading to an opening of the cylinder inner surface after a fitting member is closely fitted to the cylinder inner surface. A surface treatment method for an inner surface of a cylinder block, which is performed by packing members. 4. The surface treatment method according to claim 3, wherein the fitting member is a balloon and the sealing member is a foamed resin.