JPS6263700A - Method for positioning and fixing cathode for anodic oxidation of inside surface to aluminum pipe - Google Patents

Abstract

PURPOSE:To surely position and fix an inside cathode onto the center line of a pipe by mounting a cathode for anodic oxidation made of a spring to the mounting member disposed at one end of the pipe and pulling the cathode, then fixing the same on the outside at the other end of the pipe. CONSTITUTION:The cathode mounting member 2 having an approximately a trapezoidal plate shape is disposed to one end of the Al pipe 1 fixed to an electrolytic frame. The cathode 3 for the anodic oxidation of the inside surface which is made of the spring 3a over approximately the entire part is disposed on the center line in the pipe 1. The left end of the cathode 3 is engaged with the cathode mounting member 2 and the right end of the cathode 3 is pulled against the repulsive force of the spring 3a so that the cathode mounting member 2 contacts with the left end of the pipe 1. The right end of the cathode 3 is fixed in this state by the fixing means 4 disposed to the outside of the pipe 1. The inside cathode 3 is surely positioned and fixed onto the center line of the pipe 1 by the above-mentioned method, by which the anodically oxidized film having a uniform thickness is formed on the inside surface of the pipe 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for positioning and fixing a cathode for inner surface anodizing on an aluminum pipe.

In this specification, aluminum includes aluminum and aluminum alloys.

BACKGROUND ART In general, aluminum pipes constituting cylinder tubes of air cylinders, hydraulic cylinders, etc. used in industrial robots, vehicles, and other industrial machinery have a hard coating on their inner surface that is wear-resistant. It is designed to withstand the reciprocating movement of the piston. Conventionally, when forming a hard anodic oxide film on the inner surface of an aluminum pipe, a thin rod-shaped cathode was inserted inside the pipe, and the aluminum was used as an anode for electrolysis in an electrolyte of an inorganic or organic acid. was. However, according to the conventional method, the fixation of the internal cathode is insufficient, so
During the electrolytic treatment, the internal cathode shifts and the distance between the inner surface of the pipe and the cathode becomes uneven, which causes the thickness of the anodic oxide film formed on the inner surface of the pipe to become uneven, resulting in poor quality and even worse. In some cases, the internal cathode and the pipe come into contact and sparks are generated, which causes local melting of the pipe, resulting in the formation of defective products.

If the pipe is long, for example 2,500 mm or more, the pipe must be placed horizontally into the electrolytic frame due to the size constraints of the electrolytic cell (the tank is shallow), and this will cause internal damage. The cathode easily bends due to its own weight, and is easily misaligned due to movement of the electrolyte, and furthermore, if the inner diameter of the pipe is small, the cathode and the inner surface of the pipe are very likely to come into contact, making the above problem even more serious. There was a problem.

OBJECT OF THE INVENTION An object of the present invention is to solve the above problems and to be able to reliably position and fix the internal cathode on the center line of an aluminum pipe, thereby forming an anodic oxide film with a uniform thickness on the inner surface of the pipe. In order to provide a method that can improve the quality of the pipe, it does not generate sparks due to contact between the pipe and the internal cathode during electrolysis, and it does not produce any defective products. be.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides, at one end of an aluminum pipe fixed to an electrolytic frame, a cathode mounting member that passes through the center of the end face of the pipe and has a diameter larger than that of the end face. A cathode for internal anodizing, at least a part of which is made up of a spring, is placed on the center line inside the pipe, one end of the cathode is attached to a cathode mounting member, and the other end of the cathode is attached against the elastic force of the spring. By pulling in the length direction of the cathode, the cathode mounting member is brought into contact with one end of the pipe,
The gist of this invention is a method for positioning and fixing a cathode for inner surface anodization to an aluminum pipe, which is characterized in that the other end of the cathode is fixed in this state by a fixing means placed outside the pipe.

Example Next, this invention will be explained in detail.

1 and 2, which disclose the method of the first embodiment of the present invention, the method according to the present invention has a method in which a pipe (1) is attached to the left end of an aluminum pipe (1) fixed to an electrolytic frame (not shown). ) A substantially trapezoidal plate-shaped cathode mounting member (2) is arranged so that a part of its taper is inside when viewed from a side that passes through the center of the end face and is larger than the diameter of the same end face, and the pipe (
The inner surface anodizing cathode (3), which is made up of a full cover (3a), is placed on the center line of the inner surface of the cathode (1).
Hang the left end of the cathode (3) on the cathode mounting member (2), and then
) by pulling the right end of the tube in the length direction of the cathode (3) against the elastic force of the spring (3a), the cathode mounting member (2) is brought into contact with the left end of the pipe (1), and in this state, Cathode (3
) is fixed by a fixing means (4) placed outside the pipe (1).

The internal cathode (3) is made of aluminum, stainless steel, titanium, or the like. The cathode mounting member (2) is made of a material having chemical resistance, heat resistance, and insulation properties, such as styrene resin 1,
Use materials made from polyethylene resin, polyvinyl chloride resin, etc.

The fixing means (4) also includes a handle (4) screwed through the mouth-shaped member (5) and the upper horizontal wall (5a) thereof.
A short fixing plate (8) connected to the right end of the spring-like internal cathode (3) is connected to the tip of the bolt (6) and the lower part of the mouth-shaped member (5). The internal cathode (3) is fixed horizontally by being tightened by the horizontal wall (5b).

At the right end of the pipe (1) is an auxiliary positioning member (9) made of an insulator that is slidably fitted over the internal cathode (2).
) are located. This has a roughly trapezoidal shape when viewed from the side, with a part of the taper facing inward, and the pipe (
1) is brought into contact with the inner peripheral edge of the right end surface at two points. The spring-shaped internal cathode (3) is inserted into a cylindrical portion (10) provided horizontally in the center of the auxiliary positioning member (9). Such an auxiliary positioning member (9) is slid after the internal cathode (3) is fixed by the fixing means (4) and brought into contact with the right end of the pipe (1), thereby positioning the internal cathode (1). can be carried out more reliably.

3 and 4 show a second embodiment of the invention. Here, the difference from the first embodiment is that the internal cathode (3) is composed of a short spring (3a) and a long rod-shaped or tubular cathode (3b), and that the cathode mounting member ( 12) has a cross shape when viewed from the front, and is constituted by an insulating plate that is approximately [shaped] when viewed from the side.

According to this second embodiment, the cathode mounting member (12) is in stable contact with the left end outer peripheral edge of the pipe (1) at four points.

The other points of this embodiment are the same as those of the first embodiment, and the same parts are given the same reference numerals in the drawings.

In each of the above embodiments, the pipe (1) is arranged horizontally, but it may also be arranged so as to hang vertically. It is better to arrange the pipe vertically (1
) is easier to position the internal cathode (3).

EFFECTS OF THE INVENTION In the method for positioning and fixing a cathode for internal anodizing on an aluminum pipe according to this invention, as described above, the end face of the pipe (1) is fixed to one end of the aluminum pipe (1) fixed to the electrolytic frame. A cathode mounting member (2) (12) passing through the center and having a diameter larger than that of the same end face is arranged, and at least a part of the spring (3a) is placed on the center line inside the pipe (1).
A cathode (3) for internal anodic oxidation constituted by is arranged, one end of the negative VM (3) is attached to the cathode mounting member (2) (12), and the other end of the cathode (3) is attached to the spring (3a). By pulling the cathode (3) in the length direction against the elastic force,
The cathode mounting members (2) and (12) are brought into contact with one end of the pipe (1), and in this state, the other end of the cathode (3) is attached to the pipe (1).
), the internal cathode (3) can be reliably positioned and fixed on the center line of the aluminum pipe (1). It is possible to form an anodic oxide film of uniform thickness on the inner surface of the pipe (1), thereby improving the quality of the pipe (1). There is no generation of sparks due to contact, and there is an effect that no defective products are produced.

[Brief explanation of the drawing]

The drawings show two embodiments of this invention: Fig. 1 is a partially cutaway side view of the first embodiment, Fig. 2 is a front view of the same, and Fig. 3 is a partially cutaway side view of the second embodiment. FIG. 4 is a front view of the same. (1)...Aluminum pipe, (2)(12)...
・・Cathode mounting member, (3) ・Internal cathode, (3a)・
...Spring, (4)...Fixing means, (9)...Auxiliary positioning member. 4 people other than the above

Claims (1)

[Claims] At one end of the aluminum pipe (1) fixed to the electrolytic frame, a cathode mounting member (2) (12) passing through the center of the end face of the pipe (1) and having a diameter larger than that of the end face is arranged, and the pipe (1) an inner surface anodizing cathode (3) at least partially constituted by a spring (3a);
and attach one end of the cathode (3) to the cathode mounting member (2) (1
2) and pulling the other end of the cathode (3) in the length direction of the cathode (3) against the elastic force of the spring (3a), the cathode mounting member (2) (12) is brought into contact with one end of the pipe (1), and in this state, the other end of the cathode (3) is fixed by a fixing means (4) arranged outside the pipe (1). How to position and fix the cathode for internal anodic oxidation