JP2003342793A - Electrodeposition coating method of hub for car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrodeposition coating method of a hub for a car for improving the working efficiency and the coating quality. <P>SOLUTION: When a hub unit bearing 1 is placed on a coating tool 61, the electrodeposition coating solution 75 is pumped up from a pipe 69 to a cup part 65 in a coating solution supplying step. The pumped-up electrodeposition coating solution 75 flows into a annular groove 63, and overflows from an upper end of the cup part 65. Only a pilot cylindrical part 53 of the hub 13 is immersed in the electrodeposition coating solution 75, and a wheel fitting flange 49, an inner and face 57, or the like are exposed from the electrodeposition coating solution 75. A predetermined DC voltage is applied for a predetermined time between a positive electrode plate 71 and a negative electrode plate 73 from a control unit, and coating particles in the electrodeposition coating solution are electrodeposited as cations on a surface of a pilot cylindrical part 53. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeposition coating method for automobile hubs, and more particularly to a technique for improving work efficiency and coating quality.

[0002]

2. Description of the Related Art In recent years, in automobile axle devices and the like, in order to reduce the number of parts and the product cost, Japanese Patent Laid-Open No.
No. 000-142009 (hereinafter referred to as prior art)
As described in U.S.A., etc., so-called third generation and 3.5th generation hub unit bearings in which the components of the bearing are integrated with the components of the axle device have been developed. In the hub unit bearing of the prior art, the mounting flange of the suspension device is formed on the outer ring of the double-row angular contact ball bearing, one inner ring (first inner ring) is integrated with the hub, and the other inner ring (second inner ring) is integrated.
The inner ring is fitted and press-fitted into the inner ring holding cylinder formed on the hub. A female spline is formed on the shaft center of the hub, and a male spline of the drive shaft is fitted into the female spline, and the driving force is transmitted from the drive shaft to the hub (that is, the wheel).

The hub of the hub unit bearing is provided with a pilot cylinder portion on its side surface, which serves as a guide when the wheel is mounted. Generally, in hubs, the pilot cylinder is rust-proof by painting with oil-based or water-based paint, but the paint adheres to the flange surface with which the wheel contacts and the inner end surface with which the axle nut (washer) contacts, etc. In this case, the wheel nut or axle nut may be loosened. Therefore, the coating of the pilot cylinder portion is performed by a method such as dipping or spraying, with a masking jig being used to shield the portion other than the coating portion.

[0004]

In the conventional hub coating method, the following problems have occurred due to the use of masking jigs and the use of water-based or oil-based coatings. For example, in order to accurately cut off the coating line, the paint adhering to the masking jig had to be regularly washed, and maintenance of the paint supply means such as a spray gun had to be performed. Further, while oil-based paints have a concern about deterioration of working environment and fire due to organic solvents, water-based paints have problems with coating properties such as low peeling strength and coating strength. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electrodeposition coating method for an automobile hub, which improves work efficiency and coating quality.

[0005]

Therefore, in order to solve the above-mentioned problems, the invention of claim 1 is a method for electrodeposition coating a pilot cylinder portion of an automobile hub, which is formed on the upper surface of a coating jig. A preparatory step of mounting the automobile hub on the coating jig by fitting the pilot cylinder into the annular groove; a coating solution supplying step of supplying an electrodeposition coating solution into the annular groove; It is proposed to include a coating step of applying a voltage between an electrode connected to an automobile hub and an electrode installed on the coating jig to electrodeposit paint particles on the pilot cylinder.

According to the electrodeposition coating method for an automobile hub of the present invention, the paint is electrodeposited only on the pilot cylinder portion fitted in the annular groove, and the paint is not scattered on the non-painted portion of the hub or in the air. Further, since the electrodeposition coating liquid is an aqueous solution, the problems of working environment and fire can be solved while securing the coating film physical properties equivalent to or better than the oil-based paint.

The invention of claim 2 proposes, in the electrodeposition coating method of claim 1, a method of causing the electrodeposition coating liquid to overflow from the annular groove in the coating liquid supplying step.

In the electrodeposition coating method for an automobile hub of the present invention, since the coating parting line of the pilot cylinder is located at the upper end of the annular groove, no masking jig is required, while the electrodeposition coating liquid is an aqueous solution. Also, the work of cleaning the coating jig is almost unnecessary.

Further, the invention of claim 3 proposes the method of electrodeposition coating according to claim 1 or 2, wherein the coating liquid supplying step and the coating step are repeated a plurality of times.

According to the electrodeposition coating method for an automobile hub of the present invention, the unpainted portion in the first coating step due to air bubbles in the electrodeposition coating liquid is coated by the second and subsequent coating steps, and the rust prevention is performed. It is easy to control film thickness related to performance.

Further, in the invention of claim 4, claims 1 to 3
It is proposed that the electrodeposition coating method (1) includes a drying step of locally heating and drying the pilot cylinder portion after coating.

In the electrodeposition coating method for an automobile hub of the present invention, for example, hot air is blown to dry and harden the coated portion in a relatively short time, and the heat adversely affects other portions (bearing portion, etc.) of the work. Is less likely to occur.

In the invention of claim 5, claims 1 to 4 are provided.
It is proposed that the method of electrodeposition coating described in (1) includes a paint recovery step of recovering the paint particles in the electrodeposition coating liquid used for coating the hub of the vehicle.

According to the electrodeposition coating method for an automobile hub of the present invention, the amount of paint particles used is reduced and non-waste water is also realized.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. In the embodiment, the present invention is applied to a cationic electrodeposition coating apparatus for a 3.5th generation hub unit bearing for a drive axle in an FF (front engine / front drive) type passenger car. 1 is a vertical cross-sectional view showing a hub unit bearing according to an embodiment, FIG. 2 is a schematic configuration diagram of a coating device, FIG. 3 is a schematic configuration diagram of a drying device, and FIG. 4 is a coating material recovery line. It is a schematic diagram.

In FIG. 1, the member designated by the reference numeral 3 is the outer ring of the double-row angular contact ball bearing 5, and the first and second raceway surfaces 7, which have an arcuate section open outward, are formed on the inner peripheral sides thereof. 9 is formed. A flange 11 is formed on the outer peripheral side of the outer ring 3, and the hub unit bearing 1 is coupled to the knuckle arm (not shown) of the suspension device via the flange 11 as shown in FIG.

A first inner ring 15 integrated with the hub 13 is arranged on the side of the first raceway 7 of the outer ring 3, and on the outer peripheral side of the first inner ring 15 is the first raceway 7 of the outer ring 3. A corresponding inwardly opening arcuate cross-section raceway surface 17 is formed. A first roller row 23 including a large number of steel balls 19 and a cage 21 is interposed between the raceway surface 17 of the first inner ring 15 and the first raceway surface 7. In the figure, reference numeral 25 indicates an inner locking end, and reference numeral 27 indicates a shaft seal.

A second inner ring 31 is provided on the second raceway surface 9 side of the outer ring 3.
Is formed, and a raceway surface 33 having an arcuate cross-section that opens inward and that corresponds to the second raceway surface 9 of the outer ring 3 is formed on the outer peripheral side of the second inner ring 31. Between the raceway surface 33 of the second inner ring 31 and the second raceway surface 9, a second roller row 35 including a large number of steel balls 19 and a cage 21 is interposed.

The second inner ring 31 is externally fitted and press-fitted into a second inner ring holding cylinder 37 extending inside the hub 13, and its inner locking end 39 contacts the inner locking end 25 of the first inner ring 15. It is positioned in the axial direction by contacting, and is fixed / integrated with the hub 13 by the swing caulking 41 provided on the end portion of the second inner ring holding cylinder 37. In the figure, a member indicated by reference numeral 43 is an encoder externally fitted / fixed to the second inner ring 31, and together with the sensor fixed to the knuckle arm, outputs the hub 13 (that is, the wheel) to an electronic control unit (not shown). ) Is used to generate rotation information.

The hub 13 is formed with a wheel mounting flange 49 in which a hub bolt 47 is planted, and a wheel (not shown) is mounted on the wheel mounting flange 49.
Further, a female spline 51 is formed at the axial center of the hub 13, and a male spline formed on a drive shaft (not shown) is fitted into the female spline 51.

On the outer surface of the hub 13, there is provided a pilot cylinder portion 53 which serves as a guide when the wheel is mounted. The inner and outer circumferences of the pilot cylinder portion are rust-preventive coated to prevent rusting ( 55 is shown by a thick solid line in FIG. In the figure, reference numeral 57 indicates the inner end surface of the hub 13,
An axle nut (washer) used for fastening the hub 13 and the drive shaft is in contact with the inner end surface 57.

The coating work of the hub 13 in this embodiment will be described below. When degreasing and washing of the painted portion of the hub unit bearing 1 are completed after assembly, the hub unit bearing 1 is placed on the painting jig 61 by a worker or a transfer robot in the preparation step as shown in FIG. The coating jig 61 is a synthetic resin molded product, and includes the pilot cylinder portion 53 of the hub 13.
It has a cup portion 65 having an annular groove 63 into which is fitted and a support portion 67 extending upward from the cup portion 65. A pipe 69, into which an electrodeposition coating liquid from a paint supply device (not shown) is introduced, is connected to the axis of the cup portion 65, while an annular positive electrode plate 71 is installed on the bottom surface of the annular groove 63. . A disc-shaped negative electrode plate 73 is fixed to the upper end of the upper surface of the support portion 67.
Is in contact with the inner end surface 57 of the hub 13.

In this embodiment, when the hub unit bearing 1 is placed on the coating jig 61 in the preparation step, the electrodeposition coating liquid 75 from the coating material supply device is supplied to the pipe 6 in the coating liquid supply step.
It is pumped up from 9 to the cup portion 65. The pumped-up electrodeposition coating liquid 75 flows into the annular groove 63,
The cup portion 65 overflows from the upper end. As a result, only the pilot cylinder portion 53 of the hub 13 has the electrodeposition coating liquid 7
5, the wheel mounting flange 49, the inner end surface 57 and the like are exposed from the electrodeposition coating liquid 75.

In the next coating process, a predetermined DC voltage is applied between the positive electrode plate 71 and the negative electrode plate 73 from a control device (not shown) for a predetermined time (for example, 30 seconds), and the electrodeposition coating is performed. The paint particles in the liquid 75 become cations and are electrodeposited on the surface of the pilot cylinder portion 53. At this time, since the supplied electrodeposition coating liquid 75 overflows from the cup portion 65, the electrodeposition range (that is, parting-out) of the paint particles becomes accurate.

In this embodiment, the coating liquid supplying step (pumping up the electrodeposition coating liquid 75) and the coating step (energizing the positive electrode plate 71 and the negative electrode plate 73) are performed a plurality of times (for example, three times).
Repeat. As a result, even if an undeposited portion (crater or the like) is generated due to bubbles or flow in the electrodeposition coating liquid 75 during the first coating process, these defects are eliminated in the second and subsequent coating processes. Further, the film thickness of the coating material formed on the pilot cylinder portion 53 becomes extremely uniform, and the physical properties and appearance of the coating film are improved.

After the coating process is completed, in the drying process, the hub unit bearing 1 is placed on a drying jig 81 formed by molding a heat insulating material into a cylindrical shape, as shown in FIG. Then, a predetermined temperature (for example, 1
Hot air (50 ° C) is blown onto the pilot cylinder 53,
The coating film is dried and cured in a comparatively short time (for example, within 3 to 10 minutes) to form the anticorrosion coating 55. At this time, since the hot air is blown directly to the pilot cylinder portion 53, there is no possibility that the elastic body of the shaft seal 27 or the grease filled in the double-row angular contact ball bearing 5 is deteriorated or denatured due to the temperature rise. Further, since the temperature of the entire hub unit bearing 1 does not rise, the time required for cooling is shortened.

In the present embodiment, as shown in the schematic view of the paint recovery line of FIG. 4, the electrodeposition coating liquid 75 overflowing from the electrodeposition tank (the cup portion 65 of the coating jig 61) is UF.
By passing through the module (semi-permeable membrane device) 83,
It is separated and collected into coated particles and water. As a result, the amount of paint used is reduced, and at the same time, environmental pollution and resource saving due to non-waste water are realized.

The description of the specific embodiment is completed above.
Aspects of the present invention are not limited to the above embodiment.
For example, both of the above-described embodiments apply the present invention to a cationic electrodeposition coating apparatus for a third-generation hub unit bearing, but coats a hub unit bearing of the first generation or the second generation or a single hub. The present invention may be applied to an electro-deposition coating apparatus that uses the same, or may be applied to an anion electro-deposition coating apparatus instead of the cation electro-deposition coating apparatus. Further, in the above embodiment, the coating liquid supply step and the coating step are performed twice, but this may be performed only once, or may be performed three times or more. In addition to the structure of the coating jig and the drying jig, the means for supplying the electrodeposition coating liquid, the means for drying and curing the coating film, etc.
The present invention is not limited to the examples described in the above embodiments, and can be changed as appropriate without departing from the gist of the present invention.

[0029]

As described above, according to the method of electro-deposition coating of the hub for an automobile according to the present invention, the pilot cylinder portion of the hub for the automobile is electro-deposited and is coated on the upper surface of the coating jig. A preparatory step of placing the automobile hub on the coating jig by fitting the pilot cylinder portion into the formed annular groove, and a coating solution supplying step of supplying an electrodeposition coating solution into the annular groove. , A coating step of applying a voltage between the electrode connected to the automobile hub and the electrode installed in the coating jig to electrodeposit paint particles on the pilot cylinder, The paint is electrodeposited only on the pilot cylinder that fits in the groove, and the paint does not scatter to the unpainted part of the hub or to the air. Further, since the electrodeposition coating liquid is an aqueous solution, the problems of working environment and fire can be solved while securing the coating film physical properties equivalent to or better than the oil-based paint.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a hub unit bearing according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a coating device.

FIG. 3 is a schematic configuration diagram of a drying device.

FIG. 4 is a schematic view of a paint recovery line.

[Explanation of symbols]

1 ... Hub unit bearing 3 ... Outer ring 5 Double row angular contact ball bearing 13 ... Hub 49 ... Wheel mounting flange 53 ... Pilot cylinder 55 ... Rust prevention coating 61 ... Painting jig 63 ... Annular groove 65 ... Cup part 67 ... Support section 69 ... Piping 71 ... Positive electrode plate 73 ... Negative electrode plate 75 ... Electrodeposition coating liquid 81 ... Drying jig 83 ... UF module

Continued front page    (72) Inventor Shoichi Nishio             2-6 Kitashinmachi, Chuo-ku, Osaka-shi, Osaka             Inside the company surface treatment system

Claims (5)

[Claims] 1. A method of electrodeposition coating a pilot cylinder portion of an automobile hub, wherein the pilot cylinder portion is fitted on an annular groove formed on the upper surface of the coating jig. A preparatory step of mounting the automobile hub, a coating liquid supply step of supplying an electrodeposition coating liquid into the annular groove, and an electrode connected to the automobile hub and an electrode installed on the coating jig. A coating step of applying a voltage between the electrodes and electrodepositing the paint particles in the electrodeposition coating liquid on the pilot cylinder portion. 2. The electrodeposition coating method for an automobile hub according to claim 1, wherein, in the coating liquid supply step, the electrodeposition coating liquid overflows from the annular groove. 3. The electrodeposition coating method for an automobile hub according to claim 1, wherein the coating liquid supplying step and the coating step are repeated a plurality of times. 4. The electrodeposition coating of a hub for an automobile according to claim 1, further comprising a drying step of locally heating and drying the pilot cylinder portion after coating. Method. 5. The automobile according to claim 1, further comprising a paint collecting step of collecting paint particles in an electrodeposition coating liquid that has been used for painting an automobile hub. Coating method for car hub.