JP6717627B2 - Masking material and masking method - Google Patents

Description

The present invention relates to a masking material and a masking method.

Conventionally, in various fields including automobile manufacturing, electrodeposition coating for forming a coating film on the surface of a metal member has been performed for the purpose of rust prevention and the like. In such electrodeposition coating, an exposed portion in which a part of the surface of the metal member is exposed is often formed in order to provide the ground terminal.

The exposed portion can be formed by scraping a part of the coating film formed on the surface of the metal member after the electrodeposition coating, or by masking a part of the surface of the metal member prior to the electrodeposition coating.

When a part of the coating film is shaved to form the exposed portion, scraps of the coating film and scraps of the metal member scraped together with the coating film must be removed, which leads to a reduction in work efficiency. If the scraps of the metal member remain, it may cause rust, which is not preferable. Further, if the worker receives the vibration from an electric tool such as an air drill and removes the coating film in an unnatural posture, the burden on the worker is great. On the other hand, by masking, the exposed portion can be formed while suppressing them.

In electrodeposition coating, a metal member on which a coating film is to be formed is immersed in an electrolytic solution, and the coating film is formed by the electrodeposition action on the surface of the metallic member which is in contact with the electrolytic solution. Therefore, when the exposed portion is formed by masking, it is necessary to cover the masking portion so that the liquid does not enter and prevent the electrolytic solution from contacting the surface of the metal member at the masking portion.

For example, in the invention described in Patent Document 1, a bolt is fastened to a female screw formed on an object to be coated via a washer, and the masking portion is covered with the head and washer of the bolt so that the liquid does not enter the masking portion. I have to.

JP-A-5-287592

However, according to the conventional masking material described above, if the fastening of the bolt is weak, the liquid may enter the masking portion. Therefore, in order to prevent the liquid from entering, the bolt is turned many times to fasten the bolt strongly. It must be done, and it takes time to attach the masking material.

Further, as a result of the strong fastening of the masking material, it becomes difficult to remove the masking material, and the work of removing the masking material after forming the coating film increases.

The present invention has been made in view of these problems in the related art, and an object of the present invention is to provide a masking material and a masking method which have excellent sealing properties and can be easily attached and detached.

MEANS TO SOLVE THE PROBLEM The masking material of this invention for achieving the said objective is a masking material which is attached to the internal thread provided in the metal member and covers the said metal member, Comprising: It is integrally formed in a shaft part and one end of the said shaft part. Has a base. The shaft portion is formed of a resin together with the base portion, and can be screwed into the female screw with a smooth outer peripheral surface having a diameter equal to or larger than the inner diameter of the female screw. The base portion extends in the radial direction of the shaft portion over the entire circumference of one end of the shaft portion, and holds a ring-shaped packing around the shaft portion.

The masking method of the present invention for achieving the above object is a masking method for covering a metal member provided with an internal thread with a masking material. In the masking method of the present invention, the shaft provided with the masking material and formed of a resin is screwed onto the female screw with a smooth outer peripheral surface of the shaft having a diameter equal to or larger than the inner diameter of the female screw, The metal member together with a ring-shaped packing that is integrally formed at one end of the base portion and that extends in the radial direction of the shaft portion in the entire circumferential direction is held around the shaft portion by the base portion. , And the base and the packing seal around the female thread.

In the masking material and the masking method having the above-described configuration, the masking material is fastened to the metal member via the ring-shaped packing instead of the washer as in the above-described conventional art, and the sealing width is narrower than that of the washer. Therefore, when the masking material is fastened to the metal member, the air in the space inside the packing is pushed out by the masking material and is pushed out, and the space becomes negative pressure, and the suction force like a suction cup is generated. Occurs. In addition to the fastening force by the shaft portion, the suction force acts and the masking material firmly adheres to the metal member. Therefore, according to the present invention, excellent sealing performance can be exhibited. In addition, the adhesion is enhanced by the suction force of a suction cup, and it is not necessary to tighten it strongly as in the conventional case, so that the masking material can be easily attached and detached.

It is a perspective view of the masking material of an embodiment. It is a figure which shows the metal member of embodiment with a masking material. It is a figure which expands and shows the shank of a masking material, and the internal thread of a metal member. It is a figure which shows attachment of the masking material to a metal member. It is a figure which shows the screwing of the male screw formed in the outer peripheral surface of a shaft part, and the female screw of a metal member. It is a figure which shows the state in which the metal member was masked. It is a figure which shows the measurement of the force concerning attachment/detachment of the masking material using a push pull gauge. It is a graph which shows the relationship between the frequency|count of cooling/heating cycle and the force which attaches/removes a masking material. It is a figure shown in the state where the masking material of a modification was attached to the metal member.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the dimensional ratios in the drawings are exaggerated for convenience of explanation and differ from the actual ratios.

As shown in FIG. 1, the masking material 100 of the embodiment includes a shaft portion 110, a base portion 120, an O-ring 130 (a packing having a ring shape), and a knob 140. The masking material 100 is used in electrodeposition coating.

The shaft 110, the base 120, and the knob 140 are integrally formed of resin. The shaft 110, the base 120, and the knob 140 have electrical insulation. The resin forming the shaft portion 110, the base portion 120, and the knob 140 is, for example, a heat resistant resin such as Teflon (registered trademark), polyacetal resin, polyamide, polybutylene terephthalate, polyphenylene sulphite, but is not limited thereto. Not done.

The shaft portion 110 has a smooth outer peripheral surface 111. The base portion 120 is integrally formed at an end portion (one end of the shaft portion) opposite to the tip end of the shaft portion 110, and the end portion projects in the radial direction of the shaft portion 110 over the entire circumferential direction. .. The base 120 holds an O-ring 130 around the shaft 110. An annular groove 121 extending around the shaft 110 is formed in the base 120, and the O-ring 130 is fitted in the groove 121.

The base portion 120 has a convex portion 122 on the side surface of the groove 121. The convex portion 122 projects from the side surface of the groove 121 and is in contact with the O-ring 130. In the present embodiment, the convex portions 122 are provided at a plurality of locations in the circumferential direction along the annular shape of the O-ring 130, and from each of the plurality of locations, from the opposite side surfaces of the groove 121 so as to sandwich the O-ring 130. It is protruding. There is no particular limitation on where in the circumferential direction along the annular shape of the O-ring 130 the protrusion 122 is provided, and the protrusion 122 may be provided only on one of the opposing side surfaces of the groove 121.

The O-ring 130 is fitted in the groove 121 at a part of the outer circumference of the circular cross section, and the other part of the outer circumference of the circular cross section protrudes from the groove 121 so as to project to the tip side of the shaft portion 110.

The O-ring 130 is made of a material having heat resistance and electrical insulation. The material for forming the O-ring 130 is, for example, perfluoro rubber, acrylic rubber, silicone rubber, ethylene-vinyl acetate rubber, or the like, which has excellent heat resistance, but is not limited thereto.

The knob 140 is provided on the side opposite to the shaft 110 with respect to the base 120. The knob 140 is arranged coaxially with the shaft 110 and has a plate shape, but the arrangement and shape of the knob 140 are not limited to these. For example, the knob 140 may have an axial shape unlike the present embodiment.

As shown in FIG. 2, the masking material 100 is attached to the metal member 10, for example. The metal member 10 is subjected to electrodeposition coating to form a coating film on the surface. The masking material 100 is attached to the metal member 10 before the metal member 10 is subjected to electrodeposition coating.

The metal member 10 includes a plate material 11 and a nut 12. The nut 12 is joined to one surface of the plate material 11 by welding, for example. The metal material forming the plate material 11 and the nut 12 may be any material that can be electrodeposited, and is, for example, steel, but is not limited thereto. In the metal member 10, a female screw 13 is provided so as to penetrate the plate material 11 and the nut 12.

As shown in FIG. 3, the diameter d of the shaft portion 110 is equal to or larger than the inner diameter D1 of the female screw 13 (d≧D1). Here, the inner diameter D1 of the internal thread 13 is the diameter of a virtual cylinder that contacts the crest of the internal thread 13.

The upper limit value of the diameter d of the shaft portion 110 is not particularly limited as long as the shaft portion 110 can be attached to the female screw 13, but is, for example, not more than the diameter D2 of the valley of the female screw 13 (d≦D2). Here, the diameter D2 of the valley of the internal thread 13 is the diameter of an imaginary cylinder in contact with the bottom of the internal thread 13.

Next, a masking method will be described.

As shown in FIG. 4, the operator aligns the tip of the shaft portion 110 with the female screw 13, and in that state, pushes the shaft portion 110 while rotating it to screw it into the female screw 13. The operator rotates the knob 110 by hand to rotate the shaft 110. The worker rotates the shaft 110 to screw it into the female screw 13, and brings the base 120 and the O-ring 130 closer to the metal member 10.

As shown in FIG. 5, since the shaft portion 110 has a diameter d that is equal to or larger than the inner diameter D1 of the female screw 13 and is formed of a resin having a hardness (soft) smaller than that of the metal member 10, the shaft portion 110. The outer peripheral surface 111 is partially scraped by the female screw 13 in accordance with the rotation. As a result, the male screw 112 is formed on the outer peripheral surface 111. The shaft 110 is liquid-tightly engaged with the female screw 13 by the male screw 112.

The hardness of the metal member 10 and the shaft 110 can be defined by Vickers hardness, for example, but may be defined by other methods.

As shown in FIG. 6, the operator screw-engages the shaft portion 110 with the female screw 13 until the O-ring 130 contacts the metal member 10. Further, the worker further pushes the shaft portion 110 while rotating the shaft portion 110 to screw the shaft portion 110 into the female screw 13. Along with this, the base 120 further moves toward the metal member 10 side and presses the space 131 surrounded by the O-ring 130 and the base 120.

Unlike the present embodiment, if the masking material 100 is fastened through a washer instead of the O-ring 130 as in the prior art, the washer comes into surface contact with the metal member 10 and the base 120 over a wide area, and thus the base 120 Even if the space 131 is pressed by, the air in the space 131 does not easily escape to the outside.

On the other hand, in the present embodiment, the masking material 100 is fastened via the O-ring 130, and the metal member 10 and the base 120 are in line contact with the O-ring 130. Therefore, the seal width, which is the contact area between them, is narrower than in the conventional case, and when the space 131 is pressed by the base 120, the air in the space 131 is easily pushed out. When the air is pushed out, the inside of the space 131 has a negative pressure. As a result, a suction force such as a suction cup is generated and the masking material 100 comes into close contact with the metal member 10, and the base 120 and the O-ring 130 seal the circumference of the female screw 13.

Since the masking material 100 adheres to the metal member 10 due to the attraction force, in the present embodiment, after the O-ring 130 contacts the metal member 10, the shaft 110 is rotated many times to strongly tighten the masking material 100. You don't have to. For example, the worker rotates the shaft portion 110 for 1/4 rotation to 1 rotation after the O-ring 130 contacts the metal member 10.

After the masking material 100 is attached to the metal member 10 so as to be in close contact with the metal member 10, the worker dips the metal member 10 in the electrolyte solution in that state to perform electrodeposition coating. The electrodeposition coating itself is well known in the art, and therefore its description is omitted here.

By the electrodeposition coating, the surface of the metal member 10 excluding the masking portion, more specifically, the area of the space 131 surrounded by the base 120 and the O-ring 130, and the surface of the female screw 13 with which the shaft 110 is screwed are removed. A coating film such as an anticorrosive layer or a decorative layer is formed on the surface of the member 10.

Since the electrolytic solution does not enter the masking portion, no coating film is formed and the metal surface is kept exposed. Further, since the shaft portion 110, the base portion 120, the knob 140, and the O-ring 130 have electric insulation, no coating film is formed on them by electrodeposition coating.

After the electrodeposition coating, the operator removes the metal member 10 from the electrolytic solution, puts the masking material 100 in the drying furnace for a predetermined period of time to dry the coating film. The temperature in the drying furnace is appropriately set depending on, for example, the type and thickness of the coating film and is not particularly limited, but is, for example, 150°C to 180°C.

When it is assumed that the masking material 100 is used a plurality of times instead of being disposable, the shaft portion 110, the base portion 120, the shaft portion 110, the base portion 120, and the like so that the masking material 100 can maintain its function without being deformed even when placed in a high temperature atmosphere in a drying furnace. The heat resistant temperature of the O-ring 130 and the knob 140 is preferably 150°C to 300°C. Here, the heat resistant temperature is a continuous use temperature.

After drying the coating film, the operator removes the masking material 100 from the metal member 10. The worker removes the masking material 100 from the metal member 10 by rotating the shaft portion 110 in a direction opposite to that at the time of fastening and loosening the shaft portion 110.

The seal width of the O-ring 130 is narrower than that of the washer, and air is likely to enter the space 131 from the outside as the fastening of the shaft portion 110 is loosened. Therefore, the masking material 100 is attracted by the fastening of the shaft portion 110. It can be easily released as it is loosened.

After the coating film is dried, electrodeposition coating may be further performed without removing the masking material 100, and another coating film may be laminated on the previously formed coating film. When forming a plurality of coating films in this way, the operator removes the masking material 100 after the electrodeposition coating and the drying of the coating films are repeated to form a predetermined number of coating films.

After the masking material 100 is removed, for example, a ground terminal is fastened to the female screw 13 having an exposed metal surface and having conductivity, and the female screw 13 and the ground terminal are electrically connected.

The removed masking material 100 may be attached to another unpainted metal member 10 or another type of metal member different from the metal member 10, and can be used multiple times.

Next, the function and effect of this embodiment will be described.

According to the present embodiment, the masking material 100 firmly adheres to the metal member 10 due to the fastening force of the shaft 110 and the suction force of a suction cup. Therefore, according to this embodiment, excellent sealing properties can be exhibited. Further, the adhesion is enhanced by the action of the suction force, and the masking material 100 does not need to be strongly fastened, so that the masking material 100 can be easily attached and detached.

In the present embodiment, the shaft portion 110 has a smooth outer peripheral surface 111, and the smooth outer peripheral surface 111 is formed of resin with a predetermined diameter. Therefore, when the shaft 110 is attached to the female screw made of metal, a male screw suitable for the female screw is appropriately formed on the outer peripheral surface 111.

Therefore, for example, even when masking a plurality of types of metal members having different female threads with different pitches, it is not necessary to prepare a plurality of types of masking materials having male threads that match them. That is, according to this embodiment, one kind of masking material 100 can be applied to a plurality of kinds of metal members, and the versatility is high.

In the present embodiment, the shaft portion 110, the base portion 120, and the knob 140 are made of resin and have a hardness (softness) smaller than that of the metal member 10, so that even if the masking material 100 comes into contact with the metal member 10. The metal member 10 is not easily scratched.

Further, the resin forming the shaft 110, the base 120, and the knob 140 is a heat-resistant resin, and the O-ring 130 has heat resistance. hard. Therefore, the masking material 100 can maintain the detachability and the sealability even after being dried at a high temperature and the temperature before and after the drying is lowered. In this regard, the inventors of the present invention prototyped the masking material 100 and verified it.

The inventors of the present invention, with the masking material 100 attached to the metal member 10, immerse them in the electrolytic solution at room temperature for 1 minute, leave them in an atmosphere at 190° C. for 40 minutes, and at room temperature. The samples were left for 10 minutes in this order, and these were regarded as one cooling/heating cycle, and the number of cycles was changed. Then, the present inventors examined the force required for attaching and detaching the masking material 100 after each different number of cycles, and also examined the presence or absence of invasion of the electrolytic solution into the masking portion for several cycles.

As shown in FIG. 7, the present inventors connected the push-pull gauge 20 to the masking material 100, and measured the force required to attach and detach the masking material 100 with the push-pull gauge 20.

Specifically, the inventors of the present invention press the masking material 100 with the push-pull gauge 20 to force the shaft 110 to be inserted into the female screw 13 at the time of mounting, and pull the push-pull gauge 20 to pull the shaft. The force at the time of removal measured when the part 110 was pulled out from the female screw 13 was measured.

As shown in FIG. 8, as a result of the verification, neither the force at the time of attachment nor the force at the time of detachment changed much depending on the number of cycles, and the detachability of the masking material 100 was maintained even after heating and cooling. It could be confirmed.

Further, the present inventors checked whether or not the liquid entered the masking portion at each of the number of cycles of 0, 20, and 50, and found that the liquid did not enter in any case. .. From this, it was found that the masking material 100 exhibits a good sealing property even after being heated and cooled.

In the above verification experiment, the high temperature drying temperature was set to 190° C. in order to evaluate the performance of the masking material 100 under severe conditions, but the general temperature assumed for drying after electrodeposition coating is: For example, it is 150 to 180°C.

Therefore, if the melting point of the resin forming the shaft 110, the base 120, and the knob 140, and the O-ring 130 is 180° C. or higher, deformation due to heat is suppressed, and masking is performed while maintaining these functions. The material 100 can be used repeatedly.

Unlike the present embodiment, if the O-ring 130 is not used and the masking material 100 is to be fastened to the metal member 10 through a washer prepared separately from the masking material 100 as in the conventional case, the worker is forced to move to the center of the washer. After the shaft 110 is passed through the formed holes and they are integrated, masking must be performed.

On the other hand, in the present embodiment, since the base 120 holds the O-ring 130, such a labor is not required, and the masking work can be started quickly.

Further, in the present embodiment, since the convex portion 122 is formed on the side surface of the groove 121, the O-ring 130 is highly retainable, and the O-ring 130 is unlikely to come off the base portion 120.

In this regard, the present inventors dropped a prototype of the masking material 100 10 times from a height of 1 m, and tested whether the O-ring 130 comes off the base 120. As a result, the O-ring 130 never came off. Further, a vibration test in which vibration was continuously applied for 5 minutes was performed on the prototype, but the O-ring 130 did not come off.

Since the masking material 100 has the knob 140 and the shaft 110 is easily rotated, the work of attaching the masking material 100 to the metal member 10 is easy.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the claims.

For example, as shown in FIG. 9, the present invention includes a masking material 200 having a shaft portion 210 different from the above embodiment. The masking material 200 is the same as that of the above-described embodiment except for the configuration of the shaft portion 210.

The shaft part 210 has a stopper 212 protruding in the radial direction at its tip. A gap 214 extending from the tip to the base 120 side is formed in the shaft 210. When the masking material 200 is attached or detached, an operator brings the stoppers 212 closer to each other in the radial direction to narrow the gap 214 and thin the shaft portion 210, thereby passing the stopper 210 through the female screw 13.

In the masking material 200, since the stopper 212 is caught on the metal member 10 and is difficult to come off, the masked state can be more reliably maintained.

Further, the present invention includes a mode in which the convex portion 122 is not provided in the above embodiment. In this case, for example, the O-ring 130 is held in the base 120 by being firmly fitted in the groove 121.

The present invention also includes a form without the knob 140. Further, the shape of the base is not limited to the disk shape like the base 120 of the above embodiment, and may have a shape like a rectangular parallelepiped, for example.

The packing having a ring shape is not limited to the O-ring as in the above-described embodiment, but includes packing having a cross-sectional shape different from that of the O-ring, such as an X ring and a D ring.

In the above embodiment, the shaft 110, the base 120, and the knob 140 are formed of, for example, Teflon (registered trademark), and the O-ring 130 is formed of, for example, perfluoro rubber. According to such a configuration, the masking material 100 is excellent in heat resistance and impact resistance, so that the masking material 100 is exposed to a high temperature atmosphere many times or is repeatedly used, for example, removed from the metal member 10 for recovery. It is preferable because it is unlikely to be damaged even if it is roughly handled, such as being thrown into a box. However, the present invention is not limited to such a form in which the masking material is repeatedly used, and includes a disposable form.

The masking material does not have heat resistance and may be slightly deformed by heat during high-temperature drying, as long as it can cover the masking portion in a liquid-tight manner and can be easily removed from the metal member after the coating film is dried. The disposable masking material is attached to, for example, one metal member, and after electrodeposition coating and subsequent high temperature drying are completed, the masking material is removed from the metal member and discarded.

Further, the masking target to which the present invention is applied is not particularly limited, and may be, for example, a metal member that constitutes a vehicle body of an automobile, a train, or the like, and is used for electric appliances such as home appliances, personal computers, and smartphones. It may be a metal member.

Further, the present invention is not only applied to provide the metal member with the connection portion of the ground terminal, but also various other applications are possible. For example, in order to facilitate welding of metal members having a coating film formed on their surfaces, masking is performed by applying the present invention to a part of those surfaces to be welded parts, and The exposed portion may be formed.

10 metal members,
11 plate materials,
12 nuts,
13 Female thread provided on the metal member,
20 push-pull gauge,
100, 200 masking material,
110, 210 shaft,
111 Smooth outer peripheral surface of shaft,
112 Male screw formed on the outer peripheral surface of the shaft,
120 bases,
121 annular groove,
122 convex part,
130 O-ring (ring-shaped packing),
131 space surrounded by O-ring and base,
140 knobs,
212 stopper,
214 gap,
D1 Internal diameter of female screw,
D2 Female thread root diameter,
d Shaft diameter.

Claims (6)

A masking material which is attached to a female screw provided on a metal member and covers the metal member,
A shaft portion and a base portion integrally formed at one end of the shaft portion,
The shaft portion is formed of a resin together with the base portion, and a smooth outer peripheral surface having a diameter equal to or larger than the inner diameter of the female screw can be screwed into the female screw while being cut by the female screw.
The said base part is the masking material which is projecting in the radial direction of the said shaft part over the whole circumferential direction of the one end of the said shaft part, and is holding packing which has a ring shape around the said shaft part. The masking material according to claim 1, wherein the resin is a heat resistant resin, and the packing has heat resistance. The masking material according to claim 2, wherein the melting points of the resin and the packing are 180° C. or higher. The packing is fitted in an annular groove extending around the shaft portion in the base portion, and the base portion has a convex portion on a side surface of the groove. The masking material described in 1. The masking material according to any one of claims 1 to 4, which has a plate-shaped knob on the side opposite to the shaft portion with respect to the base portion. A masking method for covering a metal member provided with an internal thread with a masking material,
In the axial portion formed by a resin provided in the masking material, a smooth outer circumferential surface of the shaft portion having an inner diameter more than the diameter of the internal thread cut by the internal thread, while screwing the shank into the female screw ,
A base portion integrally formed with the resin at one end of the shaft portion and projecting in the radial direction of the shaft portion in the entire circumferential direction, together with a ring-shaped packing held around the shaft portion by the base portion, Move closer to the metal member,
A masking method for sealing around the female screw by the base and the packing.