JPH08326919A - Removing method for surface treatment material of metallic gasket - Google Patents

Abstract

PURPOSE: To peelingly remove a surface treatment material evenly from the surface of a metallic gasket by irradiating laser rays in the range where the surface treatment material is to be removed so as to peelingly remove the surface treatment material, when the surface treatment material spread on the metallic gasket for internal combustion engine is partially removed. CONSTITUTION: A metallic gasket 1 used for an engine is formed into a three layer construction out of upper and lower main plates 2, 3 and a sub-plate 4 interposed between both main plates 2, 3. A seal material (surface treatment material) 10 of film thickness over machined roughness is spread and baked on the joint faces to a cylinder head 5 and a cylinder 7 for the purpose of absorbing roughness due to machined tool mark. In such metallic gasket 1, for peelingly removing the seal material 10 of the parts exposed to cooling water passages 6, 8 of the seal material 10, namely, the seal material 10 of a circumferential part 16 of a communicating hole 9, a NC laser ray irradiation machine is used, laser rays are irradiated to the part 16, and the seal material 10 of the part 16 is processed to be peelingly removed by burning-off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of partially removing a surface treatment material applied to a metal gasket for an internal combustion engine such as an automobile engine.

[0002]

2. Description of the Related Art FIG. 7 is a cross-sectional view of an essential part showing a state in which a metal gasket c is interposed between a cylinder head a and a cylinder b. This metal gasket c is composed of upper and lower main plates d and e.
And a sub-plate f interposed between the upper and lower main plates d and e have a three-layer structure, and the portions exposed in the cooling water passage g of the cylinder head a and the cooling water passage h of the cylinder b are:
A communication hole i that connects the cooling water passage g and the cooling water passage h is formed.

By the way, a sealing material having a film thickness equal to or larger than the processing roughness is applied to the joint surfaces (upper and lower surfaces) of the metal gasket c with the cylinder head a and the cylinder b in order to absorb the roughness of the processing tool mark. There is. As a material for the sealing material, a soft rubber material such as NBR rubber, silicon rubber or fluororubber is often used. However, in such a metal gasket c, the sealing material of the applied sealing material, which is exposed in the cooling water passage g and the cooling water passage h, that is, the outer peripheral edge portion of the communication hole i is used for a long time. As a result of being peeled off and circulating with cooling water, fragments of the sealing material adhere to the thermostat, radiator, etc., causing engine trouble such as overheating. Therefore, in order to prevent such engine trouble,
It is necessary to peel off the sealing material exposed in the cooling water passages g and h in advance.

A method for removing the sealing material exposed in the cooling water passages g and h beforehand is, for example, Japanese Patent Laid-Open No. 59-1695.
As described in Japanese Patent Publication No. 75, a so-called sand blast method is known in which fine sand or fine particles are sprayed at high pressure on the surface of a metal gasket c coated with a sealing material to separate the sealing material. However, in such a sandblasting method, the metal gasket c is usually thin (0.10-0.
Therefore, when fine sand or fine particles are blown onto the surface of the metal gasket c at a high pressure, the metal gasket may be deformed or the metal gasket surface may be scratched after the sealing material is peeled off as shown in FIG. . Also, the sealing material at the boundary portion k with the masking is cut off obliquely, which makes it unsuitable as a gasket. Furthermore, there are many problems such as foreign matter entering between layers in the assembled state.

Therefore, in order to eliminate such inconvenience,
Japanese Patent Publication No. 4-21065 proposes a method for manufacturing a metal gasket. In this method, as shown in FIG. 9, a metal gasket c coated with a sealing material is placed on a base plate n of a masking jig m, and the upper surface of the placed metal gasket c is placed on the cooling water passage described above. g and the cooling water passage h, and the outer masking plate o and the inner masking plate p are covered, leaving a portion exposed.
The above-mentioned inconvenience is eliminated by spraying ultrahigh-pressure water s onto the portion r other than the coated portion and peeling off the sealing material from the surface of the metal gasket c by the pressure.

[0006]

However, in such a method, the outer and inner masking plates o,
Not only is p necessary, but in order to remove the sealing material from the surface of the metal gasket c at an accurate size and position, highly accurate masking plates o and p are required, which is very troublesome to manufacture. .

When the metal gasket c is beaded and then the sealing material is peeled off from the surface of the gasket c, masking plates o and p for absorbing the height of the bead are necessary. There is an inconvenience that it takes much more time. Furthermore, not only the condition that there is no gap between the masking plates o and p and the surface of the metal gasket c, but also when the ultra-high pressure water is sprayed on the part other than the part covered with the masking plates o and p In some cases, the pressure may cause the masking plates o and p to float, and the sealing material at the boundary portion q with the masking may peel off as shown in FIG. 10, resulting in a disadvantage that the product value of the metal gasket is significantly reduced.

Further, since water is used, the working environment is bad, and the peeled pieces of the sealing material are mixed in the water and adhere to the metal gasket, which requires a step of removing the pieces in a later step. There is an inconvenience. Furthermore, since the operating pressure of the ultrahigh pressure water device is as high as 1000 to 2500 MPa, there are many problems such as the need for a large and expensive device.

The present invention has been made in order to eliminate such inconvenience, and prevents the metal gasket from being deformed or scratched on the surface of the metal gasket when the surface treatment material is peeled and removed in advance. Not only can the surface treatment material at the boundary with the masking be prevented from being cut off at an angle, but accurate dimensions can be obtained from the surface of the metal gasket without using a masking plate and ultra high pressure water. It is an object of the present invention to provide a method for removing a surface-treated material of a metal gasket, which enables good removal and removal of the surface-treated material at a position and is excellent in workability and economy.

[0010]

In order to achieve such an object, a method of removing a surface-treated material of a metal gasket according to a first aspect of the present invention is a method of partially removing a surface-treated material applied to a metal gasket for an internal combustion engine. In the removing method, a laser beam is applied to an area where the surface treatment material is to be removed, and the surface treatment material is peeled off from the metal gasket.

According to a second aspect of the present invention, there is provided a method of removing a surface-treated material for a metal gasket, wherein the surface of the metal gasket is covered with a masking plate except for the area where the surface-treated material is to be removed. It is characterized by irradiating a laser beam. Here, the type of laser includes, for example, CO ₂ laser, YAG laser, excimer laser, etc., but is not particularly limited, and the laser is appropriately selected according to the type and film thickness of the surface treatment material. Set the irradiation conditions.

[0012]

According to the first aspect of the present invention, the surface treatment material of the metal gasket is burned off by irradiating a laser beam to the area where the surface treatment material is to be removed, so that the surface treatment material is evenly peeled from the surface of the metal gasket. Remove. According to the invention of claim 2, in addition to the invention of claim 1, the surface of the metal gasket is covered with a masking plate while leaving a range where the surface treatment material is to be removed, and the portion other than the covered portion is irradiated with a laser beam. This makes it possible to peel and remove the surface treatment material from the surface of the metal gasket at a more accurate size and position.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of a metal gasket used in a method for removing a sealing material of a metal gasket according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line − in FIG. 1, and FIG. FIG. 4 is a schematic cross-sectional view showing a state in which it is interposed, and FIG. 4 is an enlarged view of a main part showing a cut surface of a sealing material. In this embodiment, the case where the metal gasket is interposed between the cylinder head and the cylinder as in the conventional example is taken as an example.

First, the metal gasket 1 will be described with reference to FIGS. 1 to 3. The metal gasket 1 is composed of upper and lower main plates 2 and 3 and a sub plate 4 interposed between the upper and lower main plates 2 and 3. A three-layer structure is formed, and a communication hole 9 that connects the cooling water passage 6 and the cooling water passage 8 is formed in a portion exposed to the cooling water passage 6 of the cylinder head 5 and the cooling water passage 8 of the cylinder 7. ing. Further, a sealing material having a film thickness equal to or larger than the processing roughness is provided on the joint surface of the metal gasket 1 with the cylinder head 5 and the cylinder 7 (the upper surface of the main plate 2 and the lower surface of the main plate 3) to absorb the roughness of the processing tool mark. (Surface treatment material)
10 is applied and baked. As the material of the sealing material,
A soft rubber material such as NBR rubber, silicon rubber or fluororubber is often used. 1, reference numeral 11 is a lubricating oil hole, 12 is a bolt hole, 13 is a gasket coupling caulking hole, 14 is a cylinder bore, and 15 is a bead.

Here, in this embodiment, the metal gasket 1
The portion of the sealing material 10 applied to the exposed portion of the cooling water passage 6 and the cooling water passage 8, that is, the portion 16 around the communication hole 9 in the upper surface of the main plate 2 and the lower surface of the main plate 3 (hatched in FIG. 1). The sealing material 10) is peeled off and removed in advance. That is, by irradiating a laser beam from the irradiation port of an NC laser irradiator (not shown), which has been programmed in advance, to the portion 16 where the sealing material 10 is to be peeled off, the sealing material 10 in the portion is burned off and removed. To do. This allows the metal gasket 1 to be accurately sized and positioned.
The sealing material 10 is peeled off from the surface portion 16 and the cut surface 17 of the sealing material 10 is sharply cut as shown in FIG. In this case, it is possible to easily control the irradiation condition by setting the laser irradiation condition according to the rubber type and the film thickness of the sealing material 10 and then knowing the tendency of deterioration of the laser beam irradiation function by investigation. In the present embodiment, laser irradiation is performed by appropriately selecting laser beam management conditions within the range of an output of 5 to 200 W and a pulse of 50 to 10 kHz according to the type and thickness of the rubber of the sealing material 10. In this case, since a combustion gas is generated when the sealing material 10 is burned out by laser beam irradiation, it is preferable to install an appropriate smoke exhausting device.

In the method for removing the sealing material of the metal gasket, the sealing material 10 on the surface of the metal gasket 1 is used.
Since it is burnt out by laser beam irradiation and peeled off, it is preferable that the metal gasket 1 is deformed like the conventional sandblasting method, or the surface of the metal gasket after the peeling of the sealing material is scratched. In addition, since the cut surface 17 of the sealing material 10 can be sharply cut off, the quality of the metal gasket 1 can be improved.

Further, since the sealing material 10 can be peeled and removed from the surface of the metal gasket 1 at an accurate size and position without using a masking plate which has been conventionally required, it is not necessary to manufacture a highly accurate masking plate. Therefore, the peeling and removing work can be facilitated and the cost can be reduced. Further, the sealing material 1 is irradiated with the laser beam.
Since 0 is burned out and removed, it is possible to prevent the sealing material from peeling off at the boundary between the masking plate and the masking surface due to the pressure of ultrahigh pressure water as in the conventional case.

Furthermore, since no water is used, a good working environment can be secured, and the peeled pieces of the sealing material do not mix with water and adhere to the metal gasket.
It is possible to eliminate the step of removing the debris in the subsequent step, which is conventionally necessary, and improve workability. Further, it is possible to improve the economical efficiency because a large-sized and expensive ultra-high pressure water injection device unlike the conventional one is not required.

In the above embodiment, the laser beam is used only for burning out the sealing material 10. However, it is not necessary to limit to this, and the laser beam is used for the production lot No. of the metal gasket 1 as shown in FIG. It may be used to form the instruction marking 18 and the instruction marking 19 in the assembling direction and the assembling up-down direction. In this case, it is possible to finish more accurately, faster and neatly than the conventional marking by printing.

Further, the laser beam may be branched according to the number of cylinders to remove the sealing material 10 of the metal gasket at each cylinder at the same time. In this case, the time for removing the stripping operation is shortened and the laser irradiator is used. It is possible to reduce the number of equipments, and it is possible to reduce the cost of the peeling and removing work. Further, in the above embodiment, the metal gasket 1 having a three-layer structure is applied to the present invention, but instead of this, as shown in FIG.
The metal gasket 21 having a one-layer structure coated with 0 may be applied to the present invention. In this case, of the sealing material 10 applied to the metal gasket 21, the sealing material of the portion exposed to the cooling water passage 6 and the cooling water passage 8, that is, the portion 22 around the communication hole 9 on the upper and lower surfaces of the main plate 20. 10 is peeled and removed in advance by irradiation with a laser beam.

Further, in the above embodiment, the sealing material is peeled and removed without using the masking plate. However, the present invention is not limited to this, and as shown in FIG.
Is placed on the base plate 24 of the masking jig 23, and the surface of the placed metal gasket 1 is sealed with the sealing material 1
The outer masking plate 25 and the inner masking plate 26, which are manufactured with high precision, are covered by leaving the part 16 from which 0 is to be peeled off. The sealing material 10 may be peeled and removed by irradiating and burning off the sealing material 10 of the portion 16. By doing so, the sealing material 10 can be peeled and removed from the surface of the metal gasket 1 at a more accurate size and position.

[0022]

As is apparent from the above description, in the invention of claim 1, the surface treatment material on the surface of the metal gasket is burned off by irradiation of a laser beam to remove and remove it. It is possible to satisfactorily prevent the metal gasket from being deformed or scratched on the surface of the metal gasket after the surface treatment material is peeled off, and the cut surface of the surface treatment material can be cut off sharply. Therefore, the effect that the quality of the metal gasket can be improved can be obtained.

Further, since the surface treatment material can be peeled and removed from the surface of the metal gasket at an accurate size and position without using a masking plate, which has been essential in the past,
Since it is not necessary to manufacture a highly accurate masking plate, the peeling and removing work can be facilitated and the cost can be reduced. Furthermore, since the surface treatment material is burned off and removed by irradiation with a laser beam, the masking plate floats up by the pressure of ultra-high pressure water and the surface treatment material at the boundary with the masking peels off as in the conventional case. The effect that it can prevent is obtained.

Further, since no good water is used, a good working environment can be secured, and the debris of the surface-treated material which has been peeled off does not mix with water and adhere to the metal gasket. It is possible to eliminate the step of removing the debris in step 1 and improve the workability. Further, since it is not necessary to use a large-sized and expensive ultra-high-pressure water jetting device as in the conventional case, it is possible to obtain an effect that the economical efficiency can be improved.

According to a second aspect of the present invention, in addition to the first aspect of the invention, the surface of the metal gasket is covered with a masking plate while leaving the area where the surface treatment material is to be removed, and the portion other than the covered portion is irradiated with the laser beam. By irradiating with, it is possible to obtain the effect that the surface treatment material can be peeled off from the surface of the metal gasket at a more accurate size and position.

[Brief description of drawings]

FIG. 1 is a plan view of a metal gasket used in a method for removing a sealing material of a metal gasket according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line − in FIG.

FIG. 3 is a schematic cross-sectional view showing a state in which a metal gasket is interposed between the cylinder head and the cylinder.

FIG. 4 is an enlarged view of an essential part showing a sealing material at a boundary with masking.

FIG. 5 is a cross-sectional view of an essential part of a metal gasket of another aspect.

FIG. 6 is an explanatory perspective view for explaining another embodiment of the present invention.

FIG. 7 is an explanatory diagram for explaining a conventional example.

FIG. 8 is an explanatory diagram for explaining a conventional example.

FIG. 9 is an explanatory diagram for explaining a conventional example.

FIG. 10 is an explanatory diagram for explaining a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Metal gasket 10 ... Sealing material (surface treatment material) 16 ... Removal part of sealing material (range to remove surface treatment material) 23 ... Masking jig 25 ... Outer masking plate 26 ... Inner masking plate 28 ... Laser beam

Claims (2)

[Claims] 1. A method for partially removing a surface-treating material applied to a metal gasket for an internal combustion engine, irradiating a laser beam to an area where the surface-treating material is to be removed, and then the surface of the metal gasket is removed. A method for removing a surface-treated material of a metal gasket, which comprises peeling and removing the treated material. 2. The surface of the metal gasket is covered with a masking plate, leaving a range in which the surface treatment material is to be removed, and a portion other than the covered portion is irradiated with a laser beam. Method for removing surface treatment material of metal gasket of.