JP2004244699A - Masking method and apparatus for surface treatment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a masking method for surface treatment, which prevents a stepped portion from being formed on a boundary between the surface to be coated and a coating-unwanted surface, makes the boundary smooth, reliably prevents the leakage of a surface treatment liquid, and improves incorporation workability in a step of incorporating another part to the workpiece, by forming a surface-finished shape at an edge of the surface to be coated into a shape along a taper form; and to provide an apparatus for surface treatment. <P>SOLUTION: The masking method used when surface treating only the cylinder bore 3 of the cylinder block 1, by covering the coating-unwanted surface of a cylinder block 1 with a cap holder 6 and then filling a cylinder bore 3 of the cylinder block 1 with a surface treatment liquid, comprises forming the coating-unwanted surface contiguous to the cylinder bore 3 of the cylinder block 1 into a tapered surface 5, and sealing the surface treatment liquid by tightly contacting a tapered surface provided on the cap holder 6, with the tapered surface 5. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a masking method and apparatus for surface treatment.
[0002]
[Prior art]
BACKGROUND ART Conventionally, a cylinder block is formed of an aluminum alloy for the purpose of reducing the weight of an engine. Moreover, the inner wall surface of the cylinder bore in which the piston slides is coated with wear-resistant nickel plating or the like in order to improve durability (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-8-261555
In such a surface treatment method, a honing release surface 52b having a larger radius than the honing surface 52a of the cylinder bore 52 was formed as shown in FIG. 9 in order to prevent a step from being left in a portion where the piston could slide. In the cylinder block 51, a surface other than the honing surface 52a of the honing surface 52a of the cylinder bore 52 or the inner wall of the cylinder bore 52 is sealed with an O-ring 53 of a sealing means. Note that a plating film 54 is formed on the honing surface 52a and the tapered surface 52c of the cylinder bore 52.
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional surface treatment method, it is necessary to cut the corners with the honing release surface 52b obliquely after forming the plating film 54 by machining or the like. Sometimes, a grinding tool or the like hits the edge of the plating film 54, and the plating film 54 is easily peeled off.
Also, in the method of sealing with the tapered surface 52c, a step at the end of the plating film 54 occurs on the tapered surface 52c. In this case, the piston does not slide to the step during operation, but when the piston is inserted from the skirt side during engine assembly, the piston and the piston ring contact the step, There is a possibility that the plating film 54 may peel off or the piston and the piston ring may be damaged. In addition, it is difficult to grind such a plating step and a flower bloom on the tapered surface 52c with a tool such as a luter. In particular, in a crankcase-integrated cylinder block, accurate mechanization of chamfering work cannot be introduced. There was a problem that skill was required in the work.
[0006]
The present invention has been made in view of such circumstances, and an object of the present invention is to form a surface-treated shape at an end portion of a surface to be treated into a shape along a taper shape, thereby enabling the surface to be treated and a surface not requiring surface treatment to be formed. Prevents the formation of a step at the boundary with the surface, making it possible to form a smooth shape, reliably preventing the leakage of the surface treatment liquid, and improving the assembly workability when assembling another part to the work It is an object of the present invention to provide a method and apparatus for masking a surface treatment that can be performed.
[0007]
[Means for Solving the Problems]
In order to solve the problems of the above prior art, the present invention provides a method of processing a workpiece by covering a surface not requiring surface treatment of the workpiece with a masking jig and thereafter filling the surface of the workpiece with a surface treatment liquid. In a masking method of a surface treatment in which only a surface is subjected to a surface treatment, a surface unnecessary for surface treatment that is continuous with the surface to be processed of the workpiece is a tapered surface, and the tapered surface provided in the masking jig is adhered to the tapered surface. Seals the surface treatment liquid.
[0008]
Further, the present invention includes a masking jig for covering a surface treatment unnecessary surface of the work, and filling the surface to be treated of the work with a surface treatment liquid in a state where the surface treatment unnecessary surface is covered by the masking jig. In a surface treatment apparatus that performs surface treatment only on the surface to be treated of the work, a surface unnecessary for surface treatment that is continuous with the surface to be treated of the work is a tapered surface, and the surface treatment liquid is sealed by closely contacting the tapered surface. A tapered surface is provided on the masking jig.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail based on illustrated embodiments.
[0010]
1 to 8 show an embodiment of a masking method and apparatus for surface treatment according to the present invention. The masking method of the surface treatment in the present embodiment is applied to a cylinder block 1 as a work as shown in FIGS. The cylinder block 1 has a structure in which a crankcase 2 is integrated, and a cylinder bore 3 of a surface to be subjected to a surface treatment is provided in the cylinder block 1 so that the piston moves up and down in the cylinder bore 3. It is configured. For this reason, a plating film described later is adhered to the inner surface of the cylinder bore 3 by a film forming process for forming a film.
[0011]
At the end of the cylinder bore 3 on the side of the crankcase 2, as shown in FIGS. 2, 4, and 5, a tapered surface 5 that expands radially toward the journal portion 4 is formed. That is, the tapered surface 5 is formed continuously with the cylinder bore 3 and constitutes a part of the surface unnecessary for surface treatment covered with the cap jig (masking jig) 6 shown in FIG. Moreover, the tapered surface 5 functions as a guide for the piston 7 and the piston ring 8 (see FIG. 5) to be inserted when the engine is assembled.
[0012]
As shown in FIG. 1, the journal portion 4 of the crankcase 2 is formed with a cutout portion 9 formed by cutting out in a substantially semicircular shape along the outer periphery of the tapered surface 5. Thereby, the cap jig 6 can be easily inserted from the crankcase 2 side, and a complicated mechanism such as a diameter expanding mechanism is not required.
Furthermore, on the outer periphery of the tapered surface 5 and on the surface of the cylinder block 1 that does not require surface treatment, excessive insertion of the cap jig 6 into the cylinder block 1 is prevented, and positioning and sealing of the cap jig 6 are easily performed. A flat surface portion 10 is provided. The flat surface portion 10 constitutes a mechanism for positioning the cap jig 6 on the cylinder block 1, and is formed on a vertical surface extending in a direction orthogonal to the inner surface of the cylinder bore 3.
[0013]
On the other hand, as shown in FIGS. 3 and 4, the cap jig 6 is a columnar body having a concave portion 11 opened on one end side, and a tip portion 12 on the inner peripheral side has a tapered surface 5 on the cylinder block 1. A tapered surface 13 is provided so as to closely adhere along and seal the plating pretreatment liquid and the plating liquid (surface treatment liquid) in the radial direction toward the opposite end. The tapered surface 13 of the cap jig 6 constitutes a surface treatment device in cooperation with the tapered surface 5 of the cylinder block 1, and prevents the surface treatment liquid from leaking, and It is provided to suppress the etching action and the adhesion of the plating film 14.
[0014]
Further, the tip of the tapered surface 13 located at the tip 12 of the cap jig 6 is configured to protrude toward the inner surface of the cylinder bore 3 of the cylinder block 1. The amount of protrusion of the tip portion of the tapered surface 13 is not particularly limited, but is preferably set to be larger than the thickness of the plating film 14 formed on the inner surface of the cylinder bore 3 of the cylinder block 1. According to this, the plating film 14 formed on the inner surface of the cylinder bore 3 can be formed in a tapered shape, and the chamfering process becomes unnecessary.
[0015]
On the other hand, as shown in FIG. 6, when the tip 12 of the cap jig 6 is short and the tip of the tapered surface 13 does not protrude above the inner surface of the cylinder bore 3, a plating film 14 is formed on the tapered surface 13. This means that even after honing to the solid line 15, the step of the plating film 14 remains, which is not preferable.
As shown in FIG. 7, when the tip 12 of the cap jig 6 is longer than that shown in FIG. 6 and the tip of the tapered surface 13 is located at the same position as the inner surface of the cylinder bore 3, After the honing process, the edge of the plating film 14 does not have a tapered shape, so that a slight catch is generated. However, since the step of the plating film 14 does not remain on the tapered surface 13, there is no particular problem when assembling the engine.
Further, as shown in FIG. 8, when the tip 12 of the cap jig 6 is longer than that shown in FIG. 7 and the tip of the tapered surface 13 is arranged to protrude from the inner surface of the cylinder bore 3, the plating film 14 is formed. Of the cylinder block 1 is cut off at an angle along the tapered surface 5 of the cylinder block 1. That is, the notch 16 is formed in a portion of the plating film 14 that protrudes from the bore surface of the end portion 14a. As a result, when a tool is applied in the chamfering step, the end 14a of the plating film 14 is easily broken from the wedge-shaped notch 16 as shown by a broken line in FIG. The portion 14a is formed in a tapered shape as shown in FIG.
[0016]
As shown in FIGS. 3 and 4, a contact surface portion 17 that contacts the flat surface portion 10 of the cylinder block 1 to facilitate positioning and sealing of the cap jig 6 is provided on the distal end portion 12 side of the cap jig 6. Is provided. The contact surface portion 17 and the flat surface portion 10 of the cylinder block 1 constitute a mechanism for positioning the cap jig 6 on the cylinder block 1, and have an outer peripheral surface with respect to the rear end of the tapered surface 13 of the cap jig 6. It is formed on a vertical surface extending toward.
[0017]
Although the material of the cap jig 6 according to the embodiment of the present invention is not particularly limited, urethane rubber, silicon rubber, unilate, MC nylon, and the like are preferable in consideration of sealing properties. Although a metal cap jig can be used as the cap jig 6, stainless steel or a titanium alloy having excellent corrosion resistance is a preferable material. However, the portion in contact with the cylinder block 1 needs to have an insulating structure because the plating film 14 grows when there is conduction.
The type of plating carried out in the embodiment of the present invention is not particularly limited, and examples thereof include nickel plating.
[0018]
In order to form the plating film 14 on the inner surface of the cylinder bore 3 of the cylinder block 1 using the masking method and the surface treatment device according to the embodiment of the present invention, first, the cap jig 6 is inserted from the crankcase 2 side, The contact surface 17 is brought into contact with the flat surface 10 of the cylinder block 1, and the tapered surface 13 is brought into close contact with the tapered surface 5 of the cylinder block 1 for sealing. Next, in a general plating process in which the surface to be processed of the work is filled with a plating pretreatment solution, a plating solution, and the like, nickel plating or the like is performed using a plating device (not shown), and a plating film 14 is formed on the inner surface of the cylinder bore 3. (See FIG. 8). Then, if the plating film 14 is scraped off by a honing process or the like, the plating film 14 is finished to a predetermined thickness, and the plating film 14 having a tapered end portion 14a is obtained (see FIG. 4). Thereafter, the piston 7 with the piston ring 8 mounted thereon is inserted into the cylinder bore 3 from the direction shown by the arrow in FIG.
[0019]
In the masking method using the surface treatment apparatus according to the embodiment of the present invention, the surface unnecessary for surface treatment that is continuous with the cylinder bore 3 of the cylinder block 1 is a tapered surface 5, and the tapered surface 13 provided on the cap jig 6 is used for the cylinder block 1. Since the surface treatment liquid is sealed by covering the unnecessary surface treatment by being in close contact with the tapered surface 5, the plating film 14 is not formed on the tapered surface 5 of the cylinder block 1, and the end 14a of the plating film 14 The plating 14 is formed in a tapered shape along the tapered surface 5, and flowering of the end portion 14 a of the plating film 14 is also suppressed. Therefore, the work of chamfering the end portion 14a of the plating film 14 on the tapered surface 5 of the cylinder block 1 can be eliminated, and cost reduction and quality improvement can be achieved. The chamfering at such a place requires complicated precision and the accuracy of the end 14a of the plating film 14, so that automation is difficult, and skill is required even in the case of manual work. This is because, in particular, in the cylinder block 1 having an integrated structure in which the crankcase 2 is integrated, there is a case in which the chamfering operation itself cannot be performed because there is no degree of freedom in maneuvering a chamfering machine such as a luter.
Moreover, when the piston 7 is inserted from the side of the crankcase 2 to assemble the engine, the tapered surface 5 of the cylinder block 1 functions as a guide for the piston 7 to be inserted. The piston 7 and the piston ring 8 are extremely unlikely to be damaged or peeled off, and can be smoothly inserted and assembled to the cylinder block 1 while preventing the piston 7 and the piston ring 8 from being damaged.
[0020]
In addition, in the conventional cylinder block of the crankcase integrated type, since the journal part projects to the inner diameter side of the cylinder bore, insert the masking jig in a contracted state, and then expand the masking jig by the diameter expansion mechanism. I needed to do that. On the other hand, in the masking method using the surface treatment apparatus according to the embodiment of the present invention, the notch 9 cut out in a substantially semicircular shape along the outer periphery of the tapered surface 5 is formed in the journal 4 of the cylinder block 1. Since the cap jig 6 can be sealed simply by inserting it into the cylinder block 1 from the crankcase 2 side, a mechanism such as expanding the diameter of the cap jig 6 is not required. Simplified and inexpensive equipment can be provided.
Further, in the masking method using the surface treatment apparatus according to the embodiment of the present invention, a flat surface portion 10 perpendicular to the inner surface of the cylinder bore 3 is formed on the outer periphery of the tapered surface 5 of the cylinder block 1, and the flat surface portion 10 contacts the flat surface portion 10. Since the contact surface 17 to be in contact with is formed on the end portion 12 side of the cap jig 6 and constitutes a mechanism for positioning the cap jig 6 in the cylinder block 1, excessive insertion of the cap jig 6 can be prevented. , Positioning and sealing can be performed simply and reliably.
By the way, as a pre-plating treatment of an aluminum die-cast material (such as ADC12), a method of performing electrolytic etching using an acidic solution such as phosphoric acid is known. In such an electrical surface treatment, over-etching is liable to occur due to concentration of electric charges at corners such as a bore end. On the other hand, since the end of the cylinder bore 3 in the present embodiment is covered by the tip 12 of the cap jig 6 that is arranged so as to protrude, concentration of electric charges can be suppressed and uniform surface treatment can be performed. .
[0021]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical idea of the present invention. For example, the cylinder block 1 and the cap jig 6 of the above-described embodiment having the structure in which the journal portion 4 of the crankcase 2 is cut out in a substantially semicircular shape and can be easily sealed are formed by not only plating but also electrolytic etching or alumite. Is applicable to all surface treatments. Also, the plating method such as electroless plating and electroplating is not particularly limited, but more favorable effects can be obtained in an electroplating method that easily causes flowering.
[0022]
【The invention's effect】
As described above, the masking method of surface treatment according to the present invention covers the surface of the work that does not require surface treatment with a masking jig, and then immerses the work in a surface treatment liquid to cover only the surface to be treated of the work. In the processing, the surface treatment unnecessary surface that is continuous with the surface to be processed of the work is a tapered surface, and the surface treatment liquid is sealed by bringing the tapered surface provided in the masking jig into close contact with the tapered surface. The surface treatment liquid can be reliably prevented from leaking, and the surface treatment at the end of the surface to be treated can be shaped along the taper shape, and the stepped portion is formed at the boundary between the surface to be treated and the surface not requiring surface treatment. Can be prevented, and a smooth surface to be processed can be obtained. In addition, when assembling another component to the workpiece that has been subjected to the surface treatment by the masking method of the present invention, the workability of assembling the component can be improved because the tapered surface of the workpiece serves as a guide.
[0023]
Further, in the masking method for surface treatment according to the present invention, a flat surface extending in a direction orthogonal to the surface to be processed is provided on the surface not requiring surface treatment of the work, and a surface abutting on the flat surface is treated by the masking treatment. If the masking jig is positioned on the workpiece at the corresponding contact surface, excessive insertion of the masking jig into the surface to be processed can be prevented, and positioning and sealing of the masking jig can be easily performed. . When the tip of the tapered surface of the masking jig is arranged so as to protrude toward the surface to be processed of the work, the work of chamfering the end of the film can be easily performed. Further, the surface treatment of the work is a film forming process for forming a film on the surface to be processed, and a protrusion amount of a tip portion of a tapered surface of the masking jig is larger than a film thickness formed on the surface to be processed of the work. When it is set to be larger, the end portion of the film can be reliably formed into a tapered shape, and the chamfering process can be eliminated.
On the other hand, in the masking method for surface treatment according to the present invention, when the workpiece is a cylinder block and the surface to be treated is a cylinder bore, it is possible to prevent the concentration of charges at the end of the bore, and to provide a uniform surface with respect to the cylinder bore. Processing can be performed. In addition, when the cylinder block is formed integrally with the crankcase, and a portion of the journal formed in the crankcase projecting from the bore surface is cut out along the tapered surface of the cylinder block, Insertion is easy, there is no need to provide a complicated diameter expansion mechanism, etc., the masking jig has a simple structure, an inexpensive plating device can be used, and the piston ring can be inserted from the skirt side, and assembly workability is improved. Can be improved.
[0024]
The surface treatment apparatus according to the present invention includes a masking jig that covers the surface unnecessary for surface treatment of the work, and the surface to be treated of the work is coated with a surface treatment liquid while the surface unnecessary for surface treatment is covered by the masking jig. When the surface treatment is performed only on the surface to be treated of the work, the surface unnecessary for surface treatment continuous to the surface to be treated of the work is a tapered surface, and the surface treatment liquid is sealed by closely contacting the tapered surface. Since the masking jig is provided with the tapered surface, the same effect as the masking method of the present invention can be obtained.
[0025]
The surface treatment apparatus of the present invention may further include a positioning mechanism for positioning the masking jig on the work, wherein the positioning mechanism is provided on a surface unnecessary surface of the work, and is orthogonal to the surface to be processed. In the case of having a flat surface extending in the direction and a surface provided on the masking jig and abutting on the flat surface, the tip of the tapered surface of the masking jig is directed toward the surface to be processed of the work. When the workpiece is surface-treated, or when the surface treatment of the work is a film-forming treatment for forming a film on the surface to be treated, the amount of protrusion of the tip end of the tapered surface of the masking jig is such that Even when the thickness is set to be larger than the film thickness to be formed on the surface to be processed, the same effects as those of the masking method of the present invention can be obtained.
Furthermore, when the material of the masking jig is any of urethane rubber, silicone rubber, unilate and MC nylon, a masking jig excellent in sealing properties can be obtained. When the material of the masking jig is stainless steel or a titanium alloy, a masking jig excellent in corrosion resistance can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing a cylinder block to which a masking method for surface treatment according to an embodiment of the present invention is applied.
FIG. 2 is a sectional view taken along line AA in FIG.
3A and 3B are cap jigs used in a masking method for surface treatment according to an embodiment of the present invention, wherein FIG. 3A is a side view and FIG.
FIG. 4 is a cross-sectional view showing a state in which a taper surface of a cap jig is brought into close contact with a taper surface of a cylinder block in the masking method for surface treatment according to the embodiment of the present invention.
FIG. 5 is a cross-sectional view showing a state where a piston is inserted into a cylinder bore of a cylinder block by a masking method for surface treatment according to the embodiment of the present invention.
FIG. 6 is a cross-sectional view illustrating a masking method for surface treatment according to an embodiment of the present invention, in which a tip end of a taper surface of a cap jig to be adhered along a taper surface of a cylinder block is short, and a plating film is formed on the taper surface of the cylinder block. FIG. 4 is a cross-sectional view showing a case where is formed.
FIG. 7 is a cross-sectional view of the masking method of the surface treatment according to the embodiment of the present invention, in which the tip of the tapered surface of the cap jig which is brought into close contact with the tapered surface of the cylinder block is the same as the inner surface of the cylinder bore; It is sectional drawing which shows the case where the level | step difference of a plating film does not remain on a surface.
FIG. 8 is a plan view showing a masking method of a surface treatment according to an embodiment of the present invention. In the masking method, a tip end of a taper surface of a cap jig to be adhered along a taper surface of a cylinder block projects from an inner surface of a cylinder bore. It is sectional drawing which shows the case where a notch is formed in a film | membrane.
FIG. 9 is a cross-sectional view showing a state in which a plating film is formed on an inner surface of a bore and a tapered surface of a cylinder block by a conventional masking method of surface treatment, and a step of the plating film is formed on the tapered surface.
[Explanation of symbols]
1 Cylinder block (work)
2 Crankcase 3 Cylinder bore (surface to be treated)
4 Journal part 5 Tapered surface 6 Cap jig (masking jig)
9 Notch 10 Flat surface 12 Tip of cap jig 13 Tapered surface 14 Plating film 14a End 16 Notch 17 Contact surface

Claims (14)

In a masking method for surface treatment, in which a surface treatment unnecessary surface of a work is covered with a masking jig, and thereafter, the surface to be treated of the work is filled with a surface treatment liquid to perform surface treatment only on the surface to be treated of the work. The surface treatment unnecessary surface which is continuous with the surface to be treated is a tapered surface, and the surface treatment liquid is sealed by bringing the tapered surface provided on the masking jig into close contact with the tapered surface. Masking method. A flat surface extending in a direction perpendicular to the surface to be processed is provided on the surface not requiring surface treatment of the work, and a surface abutting on the flat surface is provided on the masking jig. The masking method for surface treatment according to claim 1, wherein is positioned on the work. 2. The masking method for surface treatment according to claim 1, wherein a tip portion of a tapered surface of the masking jig is arranged so as to protrude toward a surface to be processed of the work. The surface treatment of the work is a film forming process for forming a film on the surface to be processed, and a protrusion amount of a tip portion of a tapered surface of the masking jig is larger than a film thickness to be formed on the surface to be processed of the work. The masking method for surface treatment according to claim 3, wherein the masking is set to be as follows. 5. The masking method according to claim 1, wherein the workpiece is a cylinder block, and the surface to be processed is a cylinder bore. The cylinder block is formed integrally with a crankcase, and a portion projecting from a bore surface of a journal formed in the crankcase is cut out along a tapered surface of the cylinder block. Masking method of surface treatment. A masking jig for covering the surface not requiring surface treatment of the work, wherein the surface to be treated of the work is filled with a surface treatment liquid in a state where the surface not requiring surface treatment is covered by the masking jig; In a surface treatment apparatus that performs surface treatment only on a surface of the workpiece, a surface unnecessary for surface treatment that is continuous with the surface to be treated is a tapered surface, and the taper surface that seals the surface treatment liquid is brought into close contact with the tapered surface to perform the masking treatment. A surface treatment device provided on a tool. A positioning mechanism for positioning the masking jig on the workpiece, wherein the positioning mechanism is provided on a surface not requiring surface treatment of the workpiece and extends in a direction orthogonal to the surface to be processed; The surface treatment apparatus according to claim 7, further comprising a surface provided on the tool and abutting on the flat surface. The surface treatment apparatus according to claim 7, wherein a tip portion of a tapered surface of the masking jig is arranged so as to protrude toward a surface to be processed of the work. The surface treatment of the work is a film forming process for forming a film on the surface to be processed, and a protrusion amount of a tip portion of a tapered surface of the masking jig is larger than a film thickness to be formed on the surface to be processed of the work. The surface treatment apparatus according to claim 9, wherein the surface treatment apparatus is set to be as follows. The surface treatment apparatus according to any one of claims 7 to 10, wherein a material of the masking jig is one of urethane rubber, silicone rubber, and MC nylon. The surface treatment apparatus according to any one of claims 7 to 10, wherein a material of the masking jig is stainless steel or a titanium alloy. The surface treatment apparatus according to claim 7, wherein the workpiece is a cylinder block, and the surface to be processed is a cylinder bore. The cylinder block is formed integrally with a crankcase, and a portion protruding from a bore surface of a journal formed in the crankcase is cut out along a tapered surface of the cylinder block. Surface treatment equipment.

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