JP2001172797A - Electrolytic coloring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent color irregularity and color development defect. SOLUTION: A main frame 2 consisting of an aluminum alloy is immersed in an electrolyte 40 in an electrolytic cell 35. An anodized aluminum film is formed by a first electrolytic treatment on the outside surface of the main frame 2 and thereafter the surface of the anodized aluminum film is subjected to electrolytic coloring. A tank rail 4 of the main frame 2 is formed to a hollow form and is provided with a long hole 6a. The top end of the tank rail 4 is provided with a through-hole 6a of the diameter smaller than the diameter of the long hole 6a in a posture that the tank rail is immersed into the electrolyte 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for electrolytically coloring aluminum alloy structural members constituting a motorcycle or the like.

[0002]

2. Description of the Related Art Generally, a main frame of a motorcycle is not only a structural member but also an exterior member.
Coloring of various colors has been required for the purpose of improving the appearance design. Conventionally, these requirements have been met by painting or dyeing alumite. However, the method of coloring by painting has a problem that the texture of the underlying metal cannot be obtained because the underlying metal is covered. Also, in dyed alumite, which is colored by impregnating the dye into the alumite film formed on the surface of the underlying aluminum alloy, the dye is lower than the energy level of ultraviolet light, so the bond between C and N is released and the dye is decomposed. Color degradation occurs. To solve these problems,
The inventor of the present application attempted to adopt an electrolytic coloring method, which is one of the coloring methods for aluminum alloys.

[0003] Electrolytic coloring is carried out by adding Ni,
Any of metals such as Fe, Cu, Ag, Au, Sn
Species or plural kinds are deposited in the pores of the alumite film layer, and the color is obtained by the interference between the light reflected by the electrodeposited metal layer and the light transmitted through the alumite film and reflected on the surface of the underlying aluminum alloy. Since the light reflected on the base surface is visible, the texture of the base metal can be obtained. Further, the metal deposited in the pores is not affected by ultraviolet rays, so that the color hardly deteriorates.

[0004]

However, the main frame of the motorcycle is formed by joining members of various shapes by welding and has a complicated hollow shape, so that an opening is formed in the main frame. When the main frame is provided, when the main frame is immersed in the electrolytic solution, the electrolytic solution enters into the hollow portion from the opening and air is generated inside the hollow portion. FIG. 9 is a sectional view schematically illustrating the electrolytic coloring method performed by the inventor of the present application.
In the figure, reference numeral 60 denotes a main frame as a structural member made of an aluminum alloy, which is hollow by a box-shaped member 61 having an open surface and a side plate 62 joined by welding so as to close the opening of the box-shaped member. Is formed. 6
3 is a through hole formed in the box-shaped member 61. At the time of electrolytic treatment of the outer surface by immersing the main frame 60 in the electrolytic solution, the electrolytic solution penetrates into the hollow portion from the through hole 63, so that the electrolytic process is performed not only on the outer surface but also on the hollow portion surface.

In FIG. 1A, when the main frame 60 is immersed in sulfuric acid 64 as a primary electrolytic solution, sulfuric acid 64 flows into the hollow portion from the through hole 63. At this time, since the hollow portion is formed in a closed shape, an air pool 65 is generated above the sulfuric acid 64 flowing into the hollow portion, and the alumite film 66 is formed only at the portion where the sulfuric acid 64 is immersed. That is, when the immersion depth of the sulfuric acid at the upper edge of the through-hole 63 from the liquid level is L1, the air in the air pool 65 above the upper edge of the through-hole 63 is compressed by the liquid pressure, and the air pool 6
The liquid surface of No. 5 has a height H1 above the upper edge of the through hole 63. During the electrolytic treatment, a through hole 6 is formed on the inner surface of the hollow portion below this position from the surface of the hollow portion (+ pole) to an electrode (−pole) (not shown) arranged outside the main frame 60.
An alumite film 66 is formed by the action of the electric current passing through No. 3.

At this time, an alumite film 66 is similarly formed on the outer surface of the main frame 60. Thereafter, when the main frame 60 is pulled out of the electrolytic solution and the electrolytic solution in the hollow portion is discharged, if the secondary electrolysis is to be omitted and the tertiary electrolysis is to be performed, as shown in FIG. In addition, the main frame 60 is made of nickel sulfate 67, which is a third electrolyte.
When the immersion depth of the nickel sulfate 67 at the upper edge of the through hole 63 from the liquid surface is L2, the air in the air pool 65 above the upper edge of the through hole 63 is compressed by the liquid pressure, and the air pool is formed. The liquid surface 65 has a height H2 above the upper edge of the through hole 63. During the electrolytic treatment with the electrodes reversed, the main frame 6 is placed on the inner surface (−pole) below the hollow portion below this position.
A current flows from an electrode (+ electrode) (not shown) disposed outside the through hole 63 through the through hole 63, and nickel is deposited on the inner surface of the hollow portion. At this time, nickel is similarly deposited on the outer surface of the main frame 60.

However, since the specific gravity of the nickel sulfate 67 is larger than that of the sulfuric acid 64 as the primary electrolyte, the same acts on the air in the air reservoir 65 above the upper edge of the through-hole 63 at the same immersion depth. The hydraulic pressure increases. Therefore, the liquid level in the air pool 65 is
0 is immersed in nickel sulfate 67 higher than that immersed in sulfuric acid 64. That is, H2> H1, H2 = H1
+ ΔH. For this reason, the surface of the height ΔH where the alumite film 66 is not formed is present below the liquid surface of the nickel sulfate 67 on the inner surface of the hollow portion. During the electrolytic treatment, a current flowing from the electrode (+ electrode) (not shown) to the main frame 60 through the electrolytic solution hardly passes through the alumite film 66 having a large electric resistance. It flows more into the exposed alumite alloy surface without being formed. While nickel is electrolytically deposited on the surface of the aluminum alloy exposed below the surface of the electrolyte in the hollow portion, nickel is applied to the alumite coating 86 on the outer surface even though the outer surface is close to an electrode (not shown) disposed outside. Analysis has been difficult, and there has been a problem that color unevenness occurs and no color is generated.

The present invention has been made in view of the above-described problem of electrolytically coloring a main frame found on the basis of an experiment conducted by the inventor of the present invention, and an object of the present invention is to prevent uneven color and poor coloring. To provide an electrolytic coloring method.

[0009]

In order to achieve this object, the invention according to claim 1 forms an alumite film on an outer surface of an article made of an aluminum alloy and provided with a hollow portion and an opening, and thereafter, An electrolytic coloring method for performing electrolytic coloring, wherein a second opening having a smaller diameter than the opening is provided above the opening of the article when immersed in an electrolytic solution. Therefore, when the article is immersed in the electrolytic solution, the air in the hollow portion escapes from the second opening. As can be seen from FIG. 9 (a), when the article is immersed in the electrolytic solution, the pressure acting on the air in the hollow portion from the electrolytic solution side changes from the electrolytic solution surface formed in the hollow portion to the electrolytic solution surface outside the article. And the specific gravity of the electrolytic solution. Then, the pressure is balanced by the air in the hollow portion above the horizontal plane passing through the upper edge of the opening contracting due to the rise of the electrolyte surface in the hollow portion and increasing the pressure. Since the second opening is above the first opening, the volume of the hollow above the horizontal plane passing through the upper edge of the second opening is equal to the volume of the hollow above the horizontal plane passing through the upper edge of the first opening. Smaller than the volume. For this reason, the air in the hollow part rises with a small rise in the electrolyte level in the hollow part,
The two effects of increasing the pressure and lowering the pressure acting on the air in the hollow portion from the electrolyte side by an amount corresponding to a higher position of the electrolyte surface in the hollow portion than in the case where the second opening is not provided. Thereby, the rise of the electrolyte surface in the hollow portion is small. For this reason, the height of the electrolyte surface in the hollow portion from the upper edge of the second opening when the alumite film is formed and the height of the electrolyte surface in the hollow portion from the upper edge of the second opening in the case of electrolytic coloring. The difference can be reduced.

[0010] The invention according to claim 2 is an electrolytic coloring method for forming an alumite film on the outer surface of an article made of an aluminum alloy and having a hollow portion and an opening, and thereafter performing electrolytic coloring. The first electrolytic treatment consisting of primary or multiple electrolytic treatments for forming an alumite film and the second electrolytic treatment for electrolytically depositing a metal on the alumite film are substantially the same. And adjusting at least one of adjusting the height from the upper edge of the opening to the electrolyte surface or adjusting the ratio of the specific gravity of the second electrolytic processing solution to the specific gravity of the first electrolytic processing solution. By doing, with respect to the highest height of the height from the upper edge of the opening to the electrolyte surface in the hollow part in the first electrolytic treatment,
The height from the upper edge of the opening to the surface of the electrolyte in the hollow portion in the second electrolysis treatment is substantially equal to or smaller than the height.
Therefore, the alumite film is formed to a height substantially equal to or higher than the height from the upper edge of the opening to the electrolyte surface in the hollow part in the second electrolytic treatment. Therefore, during the second electrolytic treatment, even if the electrode is inserted into the hollow portion through the opening, even outside the article,
As in the surface of the article, it is difficult for the current from the electrode to flow into the surface below the electrode liquid level in the hollow part, so that the alumite film outside the article can be electrolytically colored.

According to a third aspect of the present invention, in the first aspect of the present invention, the posture of immersing the article in the electrolytic solution is determined by a first or a plurality of primary electrolytic treatments for forming an alumite film. The electrolytic treatment and the second electrolytic treatment for electrolytically depositing a metal on the alumite film are substantially the same, and the height from the upper edge of the second opening to the electrolyte surface is adjusted, or By adjusting at least one of the ratio of the specific gravity of the second electrolytic processing solution to the specific gravity of the 1 electrolytic processing solution, from the upper edge of the second opening to the electrolytic solution surface in the hollow portion in the first electrolytic processing The height from the upper edge of the second opening to the surface of the electrolyte in the hollow portion in the second electrolytic treatment is set to be approximately equal to or smaller than the maximum height of Therefore, in addition to the effect according to claim 1, the effect according to claim 2 is applied to the second opening above the opening, so that the alumite film on the outside of the article can be more reliably electrolytically colored.

According to a fourth aspect of the present invention, in the first to third aspects, a third opening having a smaller diameter than the opening is provided below the opening of the article when immersed in an electrolyte. . Therefore, it is possible to reduce the amount of electrolyte staying in the hollow portion when the article is pulled upward from the electrolyte, so that the electrolyte is discharged when the alumite film is formed, and the electrolyte is discharged when the electrolyte is colored. Discharge can also be carried out more easily, facilitating the work.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing the appearance of a motorcycle to which the electrolytic coloring method according to the present invention has been applied, FIG. 2 shows the same main frame, FIG. 1 (a) is a perspective view showing the entire appearance, and FIG. Is II (b) -I in FIG.
It is an I (b) line sectional view. FIG. 3 is an exploded perspective view for explaining a method of assembling the rear arm. FIG.
Is a cross-sectional view showing a state in which the electrolytic coloring method is applied,
FIG. 5 is an enlarged cross-sectional view for explaining changes in the surface of the aluminum alloy structural member when the first to fourth electrolytic treatments are performed. 6A is a cross-sectional view of an aluminum alloy structural member formed by an electrolytic coloring method, FIG. 6B is an enlarged view of a portion VI (b) in FIG. 6A, and FIG. FIG. 4 is a model diagram for explaining the mechanism of FIG. FIG. 8A is a cross-sectional view schematically showing a state in which the base materials are joined by beads, and FIG. 8B is an enlarged view of a portion VIII (b) in FIG. 8A.

In FIG. 1, a motorcycle generally designated by the reference numeral 1 is provided with a main frame 2 at the center. As shown in FIG. 2, the main frame 2 includes a head pipe 3 and a head pipe 3. A pair of tank rails 4, 4 whose front ends are welded to each other and whose rear ends are gradually separated from each other.
And rear arm brackets 5, 5 welded to the rear ends of the tank rails 4, 4, respectively. As shown in FIG. 2B, the tank rail 4 is
It consists of two side plates 6 and 7 formed of a JIS 5083 aluminum alloy wrought material (5000 series aluminum alloy) into a shallow dish shape having an opening by press working. The butted butted peripheral edges 8 are formed in a hollow shape by welding using a JIS5083 welding rod.

At the substantially center of both side plates 6 and 7 of the tank rail 4, a long hole 6 for an air cleaner is provided so as to face each other.
a, 7a are drilled, and a pair of through holes 6b, 6c are drilled at both ends of one side plate 6 as a second opening and a third opening communicating with the hollow portion. 6b,
6c is formed smaller in diameter than the long hole 6a. The rear arm bracket 5 is formed by forging or shaving wrought aluminum alloy material of JIS 5083, has a shaft bearing hole 5a, and is joined to the lower end of the tank rail 4 using a JIS 5083 welding rod. I have.

Reference numeral 9 denotes a V-type two-cylinder engine mounted on the lower side of the main frame 2, reference numeral 10 denotes a tank mounted on the upper side of the main frame 2, and reference numeral 11 denotes a seat. 1
Reference numeral 3 denotes a rear arm, as shown in FIG. 3, a pair of opposed arm members 14, 14, and these arm members 1
A cross member 15 joined so as to be interposed between the pair of arm members 14, 14; a head pipe 16 welded to the front ends of the pair of arm members 14, 14;
End brackets 17, welded to each of the rear ends of the
17.

The arm member 14 includes a lid member 18 formed by pressing a JIS 5083 wrought aluminum alloy plate material and a bent member 19 having a U-shaped cross section. It is covered with the cover member 18 and is formed in a hollow shape by welding with a JIS 5083 welding rod. Cross member 15, head pipe 16, end bracket 17 are JIS508
3 is formed by forging or shaving an aluminum alloy wrought material, and the arm member 1 is welded with a JIS5083 welding rod.
The end bracket 17 is provided with a dovetail-shaped shaft support hole 17a.

The end bracket 1 of the rear arm 13
As shown in FIG. 1, a pivot shaft 20 is suspended between the shaft bearing holes 17a and 17a of the shafts 7 and 17.
, A rear wheel 21 is rotatably supported via a bearing (not shown). Reference numeral 22 denotes a shaft suspended between the shaft support holes 5a of the rear arm brackets 5, 5 of the main frame 2, and the head pipe 16 of the rear arm 13 is rotated on the shaft 22 via a bearing (not shown). The rear arm 13 is rotatably supported on the main frame 2 around a shaft 22 as a rotation center.

Reference numeral 23 denotes a rear cushion lever,
The lower end is pivotally attached to the head pipe 16 of the rear arm 14,
The rotation of the head pipe 16 causes the upper end to rotate about the shaft 22, and the rear end of the rear cushion unit 24 is pivotally attached to the upper end. Reference numeral 25 denotes a cushion support bracket which is fixed to the engine 9 at the center and the lower end, and has a rear cushion unit 24 at the upper end.
The front end of is pivoted. Reference numeral 26 denotes an inverted front fork. The front fork 26 is rotatably supported on the front end side of the main frame 2 via bridge brackets 27 and 28. A steering handle 2 is provided on the upper end side of the front fork 26 via a bracket.
An axle 30 is horizontally mounted between a pair of inner cylinders (not shown) provided on the lower end side, and a front wheel 31 is rotatably supported on the axle 30.

Next, a method for performing electrolytic coloring on the main frame 2 will be described with reference to FIGS. In FIG. 4, reference numeral 35 denotes an electrolytic cell, and reference numeral 36 denotes a pair of opposed cathode plates provided in the electrolytic cell 35, which are connected to a negative electrode of a power source 37 via a cable. Reference numeral 38 denotes a holder for holding the main frame 2, which is formed of a conductive material, and is connected to the positive electrode of the power supply 37 via a cable. In addition, only in the tertiary electrolysis in the electrolysis treatment described below,
The connection to the power source 37 is reversed, the holder 38 is connected to the negative electrode, and the cathode plate 36 is connected to the positive electrode. A circulation pump 39 circulates the electrolytic solution 40 in the electrolytic bath 35 through a circulating passage 41 for cooling the electrolytic solution, cools it with a radiator 42, and supplies it again from the discharge nozzle 43 into the electrolytic bath 35. I have. Reference numeral 44 denotes a control unit which controls the pump 3 based on a temperature detected by a temperature sensor 45 for detecting the temperature of the electrolyte 40.
9 to control the operation and non-operation.

As shown in FIG. 2, the main frame 2 immersed in the electrolyte 40 has a pair of through holes 6b and 6c formed at both ends of a hollow tank rail 4. 4 is maintained at the upper and lower ends, and is held by the holder 38.
The posture of the main frame 2 is primary, secondary,
It is desirable to match them in the tertiary electrolysis.

In such a configuration, when the primary electrolysis constituting the first electrolysis process is performed together with the secondary electrolysis described below under the electrolysis conditions shown in Table 1, as shown in FIG. On the surface of the rail 4, an alumite coating 47 having a large number of pores 46 is formed. At this time,
Since the pair of through-holes 6b and 6c of the tank rail 4 are held by the holder 38 so as to be positioned at the upper and lower ends of the tank rail 4, the air retained in the tank rail 4 can pass through the through-hole at the upper end. 6b
There is no air accumulation in the hollow tank rail 4. Therefore, the alumite film 47 is uniformly generated on the back surface of the tank rail 4, that is, on the entire surface of the hollow portion.

As described above, the through hole 6b serving as the second opening
Is provided at the upper end of the tank rail 4 so that the air pool in the tank rail 4 can be completely removed. However, if the through-hole 6b is positioned above the opening 6a, the ΔH described with reference to FIG. 9 can be reduced, and therefore, the electrolytic coloring can be improved as compared with the related art. It is not necessary to provide the through hole 6b at the upper end. In addition, the through hole 6c, which is the third opening, is
The tank rail 4 is positioned at the lowermost end of the tank rail 4 held by the
The electrolyte solution 40 can be made to flow out of the hollow portion simply by pulling the electrolyte solution 40 vertically upward from the middle, thereby improving workability.

[0024]

[Table 1]

Next, secondary electrolysis is performed under electrolysis conditions as shown in Table 1, and the diameter of the pores 46 is increased as shown in FIG. Further, the thickness of the barrier layer 48 is adjusted by performing preliminary electrolysis under electrolysis conditions as shown in Table 1. Next, when tertiary electrolysis is performed as a second electrolysis treatment under electrolysis conditions as shown in Table 1, an electrolytic deposit 49 is deposited in the pores 46 as shown in FIG. This 3
In the primary electrolysis, in the primary electrolysis, since the alumite film 47 is uniformly generated on the entire surface of the hollow portion of the tank rail 4, the current is concentrated on the portion where the alumite film 47 is not formed. There is nothing. Therefore, the electrolytic deposit 49 is uniformly deposited in the alumite film, color unevenness is prevented, and color development is not obtained. At this stage, colors such as gray and black are obtained.

Next, in order to obtain a color development of pink, green, yellow, etc., the noble metal is replaced by electrolytic conditions as shown in Table 1, and the electrolytic precipitate 49 in FIG. The deposited metal is replaced by 50). Next, Table 1
The fourth electrolysis is performed under the electrolysis conditions as shown in FIG. 4 to increase the thickness of the barrier layer 48 as shown in FIG. This 4
In the next electrolysis, the main frame 2 as an article only needs to be simply immersed in the electrolytic solution 40.
It is not necessary to manage the height of the liquid level in the hollow part.
By positioning the cathode plate 36 outside the main frame 2, the current path flowing through the electrolyte 40 is shortened, and as described later, the cathode plate 36 flows out of the hollow surface from the outer surface of the main frame 2 (primary and secondary flows). (During tertiary electrolysis) or flow into the outer surface (during tertiary electrolysis, 36 becomes an anode plate), so that the power consumption for alumite film formation or electrodeposition can be reduced.

The mechanism of coloring in the thus formed electrolytically colored film will be described with reference to FIG. In the figure, a part of the light (incident light A) incident on the alumite film 47 is reflected at the interface of the tank rail 4 as a base material, and a part (incident light B) is reflected on the surface of the deposited metal 50. . Since an optical path difference (phase difference) occurs between the incident light A and the incident light B, a specific wavelength is enhanced or weakened by the optical path difference (phase difference), and the enhanced wavelength is increased. The color develops and the complementary color of the weakened wavelength also develops.

As shown in Table 2, the color tone of the deposited metal 50 depends on the thickness L1 of the deposited metal 50 and the thickness L1 of the barrier layer 48.
2 can be changed. That is, the deposited metal 5
Depending on the combination of the thickness L1 of 0 and the thickness L2 of the barrier layer 48, a dark color tone such as gray or blue or a pastel color tone such as pink or green can be obtained.

[0029]

[Table 2]

In the conventional coloring by dyeing, typical colors are limited to red, blue, and the like. To change the color, it is necessary to change the dye or use a different treatment tank, and the color is faded by ultraviolet rays. There was a problem. On the other hand, in the multicolor electrolytic coloring, the color can be changed by changing the processing time in the same processing tank, the weather resistance is excellent, the color does not fade, and the interference color is obtained. Therefore, there is also an effect that the color changes depending on the viewing angle.

Further, by using a JIS5083 wrought aluminum alloy, which is a non-heat-treated Al-Mg alloy, for each of the constituent members and the welding rod, the color tone of each member including the bead portion can be represented by a Lab color system (JIS Z8729). The color difference ΔE measured in the step (1) can be 10 or less. This is 5
As shown in Table 3, the 000-series aluminum alloy is a non-heat-treated Al-Mg-based alloy, and the relative movement speed of metal ions in the film is lower than that of Al during the alumite treatment in the primary electrolysis. This is because they are large and do not remain in the alumite film, so that they do not affect the color tone of the alumite film.

[0032]

[Table 3]

On the other hand, in the case of an alloy containing Si and Mg as alloy components, for example, a 6000 series alloy, these alloy components are present in the alloy in the form of an intermetallic compound called Mg ₂ Si. And is easily coarsened in the weld. Therefore, in the case of a 6000 series alloy,
A uniform color tone cannot be obtained at the bead portion.

Further, an alloy containing Cu as an alloy component, for example, a 2000-series alloy has poor alumite properties and cannot form a film having a uniform thickness, so that color unevenness occurs.

In the case of an alloy containing Si as an alloy component, for example, a 4000 series alloy, Si, which is an alloying element, remains in the alumite coating to disturb the coating structure and diffusely reflect light to obtain color. Absent.

Table 4 is a table in which materials suitable and unsuitable for electrolytic coloring of a vehicle body structural member such as a motorcycle are selected. As is clear from the table, the 5000 series is the most suitable in terms of strength, bead discoloration and the like, the 1000 series is insufficient in strength and unsuitable for the main frame 2, and the 6000 series is discolored in beads.

[0037]

[Table 4]

In FIG. 8A, 55 and 55 are base materials schematically showing the head pipe 3 and the tank rail 4, and when these base materials 55 and 55 are joined by the weld metal 56, A weld metal 56 is deposited on the base material 55, and a bead 57 having a rippled appearance is formed. Although coarse crystal grains are formed in the center of the cross section of the weld metal 55, the beads 57
Has a high cooling rate at the time of solidification, the metal structure becomes fine, and a metal structure similar to the uniform metal structure of the base material shown in FIG.

As described above, the aluminum alloy structural member is electrolytically colored and the noble metal is precipitated in the pores 46 of the anodic oxide film, thereby significantly improving the corrosion resistance of the conventional anodic oxide film. Hardness is improved and wear resistance is improved. By using such an aluminum alloy structural member for the main frame 2 of the motorcycle 1, it is possible to prevent the main frame 2 from being worn or damaged by sand or pebbles.

In this embodiment, the tank rail 4
A through hole 6b is provided at the upper end of the hole to prevent air from accumulating in the hollow tank rail 4 and to form a second opening for forming an alumite film inside the hollow portion from the upper edge of the through hole 6b. The difference between the height of the electrolyte and the height of the electrolyte in the hollow portion from the upper edge of the through-hole 6b in the case of electrified coloring is reduced, but the present invention is not limited to this. That is, as described above, in a state where the article is immersed in the electrolytic solution, the pressure acting on the air in the hollow portion from the electrolytic solution side is from the electrolytic solution surface formed in the hollow portion to the electrolytic solution surface outside the article. It becomes proportional to the height and the specific gravity of the electrolyte. Therefore, even if the tank rail 4 is not provided with the through hole 6b, the height from the upper edge of the through hole 6a to the level of the electrolytic solution 40 is adjusted, or the second electrolytic process with respect to the specific gravity of the first electrolytic process solution is performed. By performing at least one of adjusting the ratio of the specific gravity of the solution, the second maximum height from the upper edge of the through-hole 6a to the surface of the electrolyte in the hollow portion in the first electrolytic treatment is increased by the second. The height from the upper edge of the through-hole 6a to the surface of the electrolytic solution in the hollow portion in the electrolytic treatment may be substantially equal to or smaller than the height. In this case, assuming that the ratio of the specific gravity of the second electrolytic treatment liquid to the specific gravity of the first electrolytic treatment liquid is substantially the same, the immersion depth of the tank rail 4 is made to substantially match in the primary electrolysis, the secondary electrolysis, and the tertiary electrolysis. . On the other hand, it is desirable to make the immersion depth shallower in the electrolytic treatment using an electrolytic solution having a higher specific gravity, so that the liquid level from the upper edge of the through-hole 6a of the air reservoir in the hollow portion is made equal. Further, the height of the electrolyte surface in the second electrolytic treatment may be lower than the highest position of the height of the alumite film in the hollow portion formed in the first electrolytic treatment.

[0041]

As described above, according to the first aspect of the present invention, color unevenness and poor coloring are prevented.

According to the second aspect of the present invention, color unevenness and poor coloring are prevented.

According to the third aspect of the invention, it is possible to more reliably perform electrolytic coloring on the alumite film on the outer side of the article.

According to the fourth aspect of the present invention, the amount of the electrolytic solution remaining in the hollow portion when the article is pulled upward from the electrolytic solution can be reduced. The discharge of the electrolytic solution and the discharge of the electrolytic solution in the case of electrolytic coloring can also be performed more easily, and the operation is facilitated.

[Brief description of the drawings]

FIG. 1 is a side view showing the appearance of a motorcycle to which an electrolytic coloring method according to the present invention is applied.

2A and 2B show a main frame to which the electrolytic coloring method according to the present invention is applied, wherein FIG. 2A is a perspective view showing the entire external appearance, and FIG. 2B is a view II (b)-in FIG. II
(B) It is a line sectional view.

FIG. 3 is an exploded perspective view for explaining a method of assembling a rear arm to which the electrolytic coloring method according to the present invention is applied.

FIG. 4 is a cross-sectional view showing a state in which the electrolytic coloring method according to the present invention is performed.

FIG. 5 shows primary to fourth in the electrolytic coloring method according to the present invention.
It is sectional drawing expanded and shown in order to explain the change of the surface of the aluminum alloy structural member at the time of performing the next electrolytic treatment.

FIG. 6A is a cross-sectional view of an aluminum alloy structural member subjected to the electrolytic coloring method according to the present invention, and FIG. 6B is an enlarged view of a portion VI (b) in FIG. .

FIG. 7 is a model diagram for explaining a mechanism of coloring by an electrolytic coloring method according to the present invention.

FIG. 8A is a cross-sectional view schematically showing a state in which base materials colored by the electrolytic coloring method according to the present invention are joined by beads, and FIG. 8B is a VIII in FIG. 8A.
It is an enlarged view of (b) part.

FIG. 9 is a cross-sectional view schematically illustrating an electrolytic coloring method performed by the inventor of the present application.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Motor cycle, 2 ... Main frame, 4 ... Tank rail, 6b, 6c ... Through-hole, 35 ... Electrolyte tank, 36 ... Cathode plate, 37 ... Power supply, 38 ... Holder, 40 ... Electrolyte, 46
... pores, 47 ... anodized film, 48 ... barrier layer, 49
... Electrolytic deposit, 50 ... Deposited metal.

Claims (4)

[Claims] 1. An electrolytic coloring method for forming an alumite film on an outer surface of an article made of an aluminum alloy and having a hollow portion and an opening, and thereafter performing electrolytic coloring, wherein the article is immersed in an electrolytic solution. Wherein a second opening having a smaller diameter than the opening is provided above the opening. 2. An electrolytic coloring method for forming an alumite film on an outer surface of an article made of an aluminum alloy and having a hollow portion and an opening, and thereafter performing electrolytic coloring, wherein an immersion posture of the article in an electrolytic solution is determined. A first electrolytic treatment comprising a primary or multiple electrolytic treatment for forming an alumite film and a second electrolytic treatment for electrolytically depositing a metal on the alumite film are substantially the same, The first electrolytic treatment is performed by adjusting at least one of the height from the edge to the electrolyte surface and the ratio of the specific gravity of the second electrolytic treatment solution to the specific gravity of the first electrolytic treatment solution. With respect to the maximum height of the height from the upper edge of the opening to the surface of the electrolyte in the hollow portion, the height from the upper edge of the opening to the surface of the electrolyte in the hollow portion in the second electrolytic treatment is substantially the same, Small height and An electrolytic coloring method, characterized in that: 3. The electrolytic coloring method according to claim 1, wherein
The immersion posture of the article in an electrolytic solution is determined by a first or a plurality of electrolytic treatments for forming an alumite film.
The electrolytic treatment and the second electrolytic treatment for electrolytically depositing metal on the alumite film are substantially the same, and the second
By adjusting the height from the upper edge of the opening to the electrolyte surface, or adjusting at least one of the ratio of the specific gravity of the second electrolytic processing solution to the specific gravity of the first electrolytic processing solution, For the highest height of the height from the upper edge of the second opening to the electrolyte surface in the hollow part in the first electrolytic treatment,
An electrolytic coloring method, characterized in that the height from the upper edge of the second opening to the surface of the electrolyte in the hollow portion in the second electrolytic treatment is substantially equal to or smaller than the height. 4. The electrolytic coloring method according to claim 1, wherein a third opening having a smaller diameter than the opening is provided below the opening of the article when immersed in an electrolytic solution. Electrolytic coloring method.