JPH0642647A - Method for working metal gasket - Google Patents

Abstract

PURPOSE:To radiate heat and prevent a metal base plate from deformation in the metal base plate having beads formed in the peripheral edge of an opening corresponding to a cylinder bores and a shim plate stuck to the peripheral edge of the opening side flat part by avoiding the overlapping of the diameters of spot welds in parts close to the bore. CONSTITUTION:A metal gasket interposed between splice surfaces of a cylinder head and cylinder block of an internal combustion engine has a metal gasket body 1 made of an elastic base plate 2 provided with a plurality of cylinder bores #1, #2... while provided with beads concentrically with the respective bores #1, #2.... Also a shim plate 4 is provided from the bead 3 to the peripheral edge of the bore side flat part. While the respective shim plates are stuck to the peripheral edges by spot welding 5, the diameters of the spot welds in the vicinity A of the bores are adapted not to overlap each other, i.e., the rate of the pitch P of the spot welds to the diameter D of the welds (P/D) is set to at least 1.2 to reduce thermal distortion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal used for preventing leakage of combustion gas, cooling water, lubricating oil, etc., which is provided on a joint surface between a cylinder head and a cylinder block constituting an internal combustion engine. The present invention relates to a gasket processing method.

[0002]

2. Description of the Related Art In an internal combustion engine, a metal gasket is interposed between a cylinder head and a cylinder block and tightened to provide a sealing function. The metal gasket used in this case has a basic structure in which a bead is formed on the peripheral edge of the elastic substrate corresponding to the bore hole. Then, a metal gasket is installed in the engine, tightened with bolts, and the reaction force due to the compressive deformation of the bead is used for sealing. Therefore, in order to prevent fatigue damage due to expansion and contraction of the bead due to repeated explosions when the engine is operating, a sub plate (shim plate) is fixed to the flat part near the bore of the bead (actual opening No. 2-6855). For example, spot welding using a laser beam is performed (Japanese Patent Laid-Open No. 4-157263).

[0003]

According to the above fixing method, spot welding is performed at predetermined intervals over the peripheral edge of the bore. However, recent engines are smaller, lighter, and have higher performance.
The distance between the cylinder bores has become very narrow, the board thickness is 0.20-0.30 mm, and the shim board thickness is 0.08-0.
It is about 15 mm. When spot welding is continuously performed, there is no problem in a portion having a large heat conduction area, but since a range in which heat escapes is narrow between the cylinder bores having a narrow gasket width, thermal strain occurs, which causes large deformation. The present invention has been made to solve the above drawbacks, and an object of the present invention is to provide a method for processing a metal gasket that prevents thermal distortion of a substrate.

[0004]

In order to achieve the above object, in the present invention, when a shim plate having a thickness smaller than that of the substrate is spot-welded to the peripheral edge of the gasket side bore corresponding to the cylinder bore, the cylinder bores are brought close to each other. The parts were welded so that the diameter of the spot welds did not overlap. In this way, the amount of heat generated at the portions where the cylinder bores are close to each other is small, and the substrate is not deformed.

[0005]

Embodiments will be described below with reference to the drawings. Figure 1
FIG. 4 is a configuration diagram of an embodiment for explaining a method for processing a metal gasket according to the present invention, in which only essential parts are shown. In the figure,
Reference numeral 1 is a metal gasket body, which is a substrate 2 made of an elastic material.
Are provided with cylinder bores # 1, # 2, ..., A bead 3 is provided concentrically with each cylinder bore, and a shim plate 4 is fixed to a flat portion on the bore side of the bead. FIG. 2 is a sectional view taken along line CC of FIG. 1, and 5 is a spot weld. In addition, 6 of FIG. 1 is a bolt hole.

Next, a spot welding method will be described. In the present invention, the method of spot welding is divided into three ranges between the adjacent cylinder bores. First, as shown in FIG. 1, 20 ± 5 mm above and below the midpoint z on the line connecting the center point x of the # 1 cylinder bore and the center y of the # 2 cylinder bore.
Range (hereinafter referred to as range A), and both sides from the range
The method of spot welding is divided into three ranges, a range of 10 ± 5 mm (hereinafter referred to as range B) and a range other than that (hereinafter referred to as other range). That is, as shown in FIG. 3, in the range A, the ratio of the pitch P of the spot welded portion to the welded portion diameter D (welded portion diameter ratio P / D) is 1.2 or more, and in the other range C, the welded portion diameter ratio is 0.8. ± 1 and in the range B was set to an intermediate value. From the above, it was confirmed that thermal distortion was small between the cylinder bores and there was no deformation, and a product that was harmonious as a whole could be produced. FIG. 4 is a diagram illustrating a jig for spot welding. In FIG. 4, reference numeral 7 is a table, and the cylinder bore of the substrate 2 is aligned with the opening 8 and the pressing base 9 is attached from above.
Then, the positions are aligned and spot welding is performed by the focus head 10 from above. In this case, even if the table 7 is rotated,
The head side may be rotated.

[0007]

As described above, according to the present invention, when the shim plate is fixed to the substrate, the spot welding position is made rough in the narrowest portion between the cylinder bores, and the spot welding position is set farther from the portion. Since the spot welding positions are made denser in sequence, heat can be dissipated rationally, and a method for processing a metal gasket without deformation of the substrate can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment illustrating a method for processing a metal gasket according to the present invention.

FIG. 2 is a sectional view taken along line CC of FIG.

FIG. 3 is a diagram illustrating a spot welded portion.

FIG. 4 is a diagram illustrating a jig for spot welding.

[Explanation of reference symbols] 1 metal gasket body 2 substrate 3 bead 4 shim plate 5 spot weld 6 bolt hole 7 table 8 open hole 9 presser foot

Claims (2)

[Claims] 1. A metal gasket in which a bead is formed on a peripheral edge of an opening corresponding to a cylinder bore of an elastic metal substrate, and a shim plate is fixed to a peripheral edge of a flat portion on the opening side of the bead. Is a method for processing a metal gasket, characterized in that the diameter of the spot weld is prevented from overlapping. 2. When the distance between the centers of the spot welds is P, the diameter of the spot welds is D, and P / D is the weld diameter ratio,
The weld diameter ratio should be 0.8 ± 1 except 20 ± 5 mm above and below the line between the cylinder bore centers, and 1.2 or more for the weld diameter ratio 10 ± 5 mm above and below the line between the bore centers. A method for processing a metal gasket, characterized in that the weld diameter ratio between is set to an intermediate value between 1.2 and 0.8.