JP2000161377A - Nylon coating method for spline part of universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate cutting machining, reduce expenditure required in disposal of cutting chips, and thereby lower the cost required by making equipment common even if each spline part to be applied with nylon coating is different in size, and making the film of nylon coating arbitrary and uniform in thickness. SOLUTION: After a substrate treatment for the inner circumferential tooth surface of the spline sleeve 1 of an universal joint is performed by a shot blast primer coating device 4. The spline sleeve 1 is kept at grounding potential, and concurrently, it is rotated by a rotating device 3 so as to be heated up to a constant temperature by a heating device. Electrically charged nylon powder is injected in a radial form out of the tip end of a spray gun 5 so as to be sprayed over the inner circumferential tooth surface, so that nylon is electrostatically coated. After coating is over, shower is sprayed thereon by a cooling device 8, and coated nylon is thereby to be fixed thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coating a sliding portion of a spline shaft or a spline sleeve of a universal joint with nylon.

[0002]

2. Description of the Related Art In order to reduce frictional resistance during sliding at a spline portion of a universal joint and to reduce wear, a nylon coat is applied to either an outer peripheral tooth surface of a spline shaft or an inner peripheral tooth surface of a spline sleeve. It is being done.

As shown in FIG. 5, the conventional nylon coating method employs a fluid immersion method. That is, the spline shaft 11 that has been subjected to a base treatment such as shot blasting or primer is heated in a heating furnace (not shown), and air 13 is sent into the fluid immersion device 12 to cause the nylon powder 1
4 is immersed in a fluidized immersion bed in a fluidized state for a certain period of time. The nylon powder 14 adheres to the spline shaft 11 and is melted by the heat, that is, welded.

Spline shaft 1 with nylon welded
After taking out 1 from the fluidized immersion bed and cooling, cutting is performed in order to finish it to the reference size.

[0005]

However, the conventional nylon coating method using the fluidized dipping method has the following problems.

(1) In accordance with the outer diameter and length of a workpiece such as a spline shaft to be coated with nylon, an apparatus such as a heating furnace or a fluidized immersion floor is required. For this reason, this fluid immersion method was mainly applied to small items of 200φ or less, and dedicated equipment was expensive for large and medium items of 225φ or more, so that it could not be practically commercialized.

[0007] (2) After nylon coating, cutting is required to finish to a standard size. In addition, a dedicated cutting jig according to the size of the workpiece is required.

(3) Furthermore, all of the nylon chips generated during the cutting process (approximately 50% is scrap) are industrial waste, and the disposal process is charged, resulting in a large loss cost. And that translates into increased costs.

The present invention solves the above-mentioned problems of the prior art. The same equipment can be used in common, and the nylon to be welded can be arbitrarily and uniformly formed. Accordingly, it is an object of the present invention to provide a method of coating nylon on a spline portion of a universal joint, which does not require cutting, reduces waste disposal costs, and can be implemented at low cost.

[0010]

In order to achieve the above object, a nylon coating method according to the present invention provides a universal joint having a spline portion surface treated with a groundwork, the spline portion is kept at a ground potential, and is fixed. The method is characterized in that nylon which is heated to a temperature and charged is sprayed onto the surface of the spline portion by a spray gun to electrostatically coat nylon.

In this case, the spray gun is moved relative to the spline portion in the axial direction to spray the spline portion. In particular, when the spline portion is that of the spline sleeve, the spline sleeve is rotated, and while the spray gun inserted inside the spline sleeve is moved in the axial direction of the spline sleeve, nylon powder is sprayed radially from the spray gun.

According to the above method, nylon coating treatment can be performed with the same equipment from medium-sized to large-sized products.
Equipment can be shared. In addition, since nylon coating with an arbitrary and uniform film thickness is possible, cutting is not required, effective use of nylon raw materials, and reduction in cost can be achieved without producing industrial waste.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a schematic configuration of a nylon coating apparatus and a method for coating a spline sleeve of a universal joint with nylon according to an embodiment of the present invention.

Reference numeral 1 denotes a spline sleeve which is a workpiece, which is coated with nylon on an inner peripheral tooth surface (spline portion). Reference numeral 2 denotes a heating device, which is placed on the spline sleeve 1 and rotated by a rotating device 3 as shown by an arrow A to uniformly heat. 4 is a shot blast / primer coating device for pre-treating the inner peripheral tooth surface of the spline sleeve 1;
Reference numeral 5 denotes a spray gun that sucks the nylon powder 7 stored in the tank 6 and radially ejects the powder from the tip. The shot blast / primer coating device 4 and the spray gun 5 are inserted into the spline sleeve 1 and
(In the direction of arrow B). Reference numeral 8 denotes a cooling device, which cools the heated spline sleeve 1 by shower spraying after the nylon coating is completed. Reference numeral 9 denotes a bellows-type painting booth that surrounds the whole as necessary so that shot particles during base treatment and nylon powder during nylon coating do not scatter.

Next, the nylon coating process in the present embodiment will be described. First, spline sleeve 1
Is placed on the heating device 2 and rotated by the rotating device 3, and the base treatment is performed in advance while moving the shot blast and primer coating device 4 inserted into the spline sleeve 1 in the axial direction.

Next, the spline sleeve 1 is rotated by the rotating device 3 (0 to 50 rpm), and the required temperature (about 200 to 230 ° C.) is increased by the heating device 2 to make the entire temperature uniform. At this time, the spline sleeve 1 is set to the ground potential. When the temperature reaches a predetermined temperature, heating is stopped, and nylon powder is radially ejected from the tip of the spray gun 5 while moving the spray gun 5 inserted into the spline sleeve 1 in the axial direction. At this time,
A positive voltage (5 to 60 kV) is applied to the nylon powder to give a charge. The nylon powder ejected with the electric charge is drawn to the tooth surface of the spline sleeve 1 maintained at the ground potential, adheres and fuses.

When the nylon coating is completed, the cooling device 8
Is sprayed from the outside of the spline sleeve 1 and cooled to 150 ° C. or lower to fix the welded nylon.

FIG. 2 shows a process flow of the above nylon coating. As shown in FIG. 3, the nylon coating on the tooth surface of the spline sleeve 1 is uniformly and uniformly adhered, and the amount of powder to be ejected (35 to 100 g / min) and the moving speed of the spray gun (1
The thickness can be controlled to an arbitrary thickness (0.2 to 0.5 mm) by adjusting the thickness to a value within a range from 00 to 500 mm / min. Also, by adjusting the electrostatic voltage, the force with which the nylon powder is attracted to the surface to be coated can be adjusted, so that the size of the workpiece can be changed from a medium-sized product (225φ) to a large-sized product (90φ).
It is possible to perform nylon coating in a wide range up to 0φ).

FIG. 4 shows the relationship between the axial force (N) and the coefficient of friction (μ) depending on the presence or absence of the nylon coat.

In the embodiment, the case where the inner peripheral tooth surface of the spline sleeve is coated with nylon is shown, but the outer peripheral tooth surface of the spline shaft may be coated. However, in consideration of heating, powder scattering prevention, and the like, it is more effective to coat the spline sleeve with nylon.

[0021]

As described above, according to the present invention, (1) the same equipment can be shared from medium to large products by electrostatically coating with nylon.
Equipment costs can be reduced.

(2) A simple electrostatic nylon coating can be applied to a spline part of a large product, which was difficult in the past, so that the wear resistance can be improved at low cost and the spline part has a long life. Can be achieved.

(3) A uniform thickness can be arbitrarily formed by the electrostatic nylon coating method, so that cutting for finishing is not required, and the number of steps can be reduced by shortening the manufacturing process and time. 100% effective use of nylon raw materials.

(4) Since there is no nylon waste generated by the cutting process, it is not necessary to dispose of industrial waste, so that costs can be reduced and costs can be reduced.

(5) The heating of the processing member does not require a high-precision heating furnace and can be directly performed by a burner, so that the cost can be reduced.

(6) Since local heating with a burner is possible, the tip of the spray gun is changed to a unidirectional one to locally apply an electrostatic type nylon coat and obtain a film thickness accuracy (5/100). ) Can also be used for repair and anticorrosion, which do not require).

(7) Since the work steps can be integrated into one place, there is no loss between the work steps, leading to an increase in work efficiency.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a nylon coating apparatus and a method of coating a spline sleeve of a universal joint with nylon according to an embodiment of the present invention.

FIG. 2 is a diagram showing a process flow of nylon coating in one embodiment of the present invention.

FIG. 3 is a diagram showing a nylon coating film on an inner peripheral tooth surface of a spline sleeve.

FIG. 4 is a graph showing the relationship between the axial force and the coefficient of friction with and without a nylon coat.

FIG. 5 is a diagram showing a nylon coating method by a conventional fluid immersion method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 spline sleeve 2 heating device 3 rotating device 4 shot blast / primer coating device 5 spray gun 6 tank 7 nylon powder 8 cooling device 9 bellows type coating booth 10 dust collector

Claims (3)

[Claims] After the surface of the spline portion of the universal joint is ground-treated, the spline portion is heated to a predetermined temperature while being kept at a ground potential, and charged nylon powder is sprayed on the surface of the spline portion by a spray gun. A nylon coating method for a spline portion of a universal joint, characterized in that nylon is electrostatically coated by spraying on a nylon. 2. The method for coating nylon on a spline portion of a universal joint according to claim 1, wherein the spray gun is relatively moved in the axial direction of the spline portion and sprayed. 3. When the spline portion is that of a spline sleeve, while rotating the spline sleeve and moving the spray gun inserted inside the spline sleeve in the axial direction of the spline sleeve, the nylon powder is discharged from the spray gun. 2. The method according to claim 1, wherein the spline is sprayed.