JPH07284962A - Method for welding end metal tool having wear resistance and slidingly moving curved surface - Google Patents

Abstract

PURPOSE:To prevent the lowering of hardness on the hardened surface and obviate re-quenching and tempering treatment by electrically resistance-welding a steel-made end metal tool having a curved surface executing the surface hardened treatment in the cooling condition in the water. CONSTITUTION:The steel-made end metal tool 2 having the curved surface beforehand executing the surface hardened treatment is electrically resistance- welded to the end peripheral edge part of the metallic member in the cooling condition in the water. For this purpose, the water surface level 6 is positioned at least at position that be lower than the welding part and that a lower electrode 5 is made to be almost dipped in the water. Further, the water in a water vessel 3 is made to flow by flow-circulation or flow-in and flow-out. By this method, the generation of the heat at the fuse-stuck fixing part is released by cooling with the water. Then, the lowering of the hardness at the spherical surface or the recessed surface or the projected surface of the end metal tool 2 is prevented, and the re-quenching and tempering treatment is obviated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to wear resistant slides used in the manufacture of internal combustion engines, such as push rods for valve actuations for operating intake valves and exhaust valves inside the engines and ball joints for axial plunger pumps. The present invention relates to a method for welding end fittings having a curved surface.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing a push rod, for example, as shown in FIG. 5, a surface hardening treatment (usually Hv
650 or more), and the pipe member with the back side of the steel end fitting (12) having a curved concave surface or convex surface such as a spherical surface serving as a sliding surface abutting and mounting. One of the two is held by the tube-side electrode (13) divided into two parts, and the end fitting (12) is abutted against the curved concave surface or convex surface by the end fitting-side electrode (14) from above by electric resistance welding. It was a method of energizing and welding and fixing with pressing down the core.

[0003]

However, in such a conventional technique, the instantaneous welding current and the energization time are generally defined in relation to obtaining the required welding strength at the end fitting (12). Of the end fittings (1)
2) The hardness of the curved concave or convex portion formed by 2) causes a decrease in hardness after welding (around Hv500). Therefore, the end metal fitting (12) side is again hardened to a specified hardness by a burner or high frequency. Then, if necessary, a tempering process will be inevitably performed, increasing the number of working steps, and at the same time, causing the heat treatment to cause discoloration (temper color) near the welded portion of the pipe member (11) including the end fitting (12). The tube side electrode (13), which is in contact with the tube member (11) in a wider area, has a low current density and a small temperature rise, but locally contacts the end fitting (12). End fitting side electrode (1
Since 4) has a high current density and the temperature rises sharply, there are problems such as generation of electrically insulating oxide scale accompanying this temperature rise, adhesion and improper energization resulting in unstable welding. It was a thing.

The present invention has been made in view of the above problems of the prior art. The heat generated in the welding fixing portion is immediately dissipated by cooling with water, and at least the spherical surface of the end fitting that abuts the electrode. Etc., effectively preventing a decrease in hardness on a curved concave surface or convex surface, eliminating the need for re-quenching and tempering treatment with the end fitting, and at least in a portion submerged in water by blocking contact with air. Eliminates thermal discoloration (temper color) to improve quality value, and suppresses sparking during welding by welding in water, which has a higher electrical conductivity than air, and enables the lower electrode to be used for a long time. It is an object of the present invention to propose a welding method for an end fitting having a wear-resistant sliding curved surface that can be formed.

[0005]

In order to achieve the above-mentioned object, the present invention abuts a back end of a steel end fitting having a curved surface with a hardened surface on the peripheral edge portion of a metal member. In the method of electric resistance welding accompanied by the downward pressing of the shaft core, the gist is a welding method of an end metal having a wear-resistant sliding curved surface obtained by electric resistance welding the end metal in a cooled state in water. Further, the water level surface is not lower than at least the welded portion and the lower electrode is substantially submerged, and water in the water tank container is circulated by inflow circulation or inflow discharge.

[0006]

Since the present invention is based on such a welding method, heat is generated in the welded and fixed portion by carrying out the end fitting which has been surface hardened in advance in the electric resistance welding while being cooled in water. As a result, the heat is immediately dissipated as it cools with water, and therefore, it is possible to effectively prevent deterioration of the hardening at least on the curved concave surface or convex surface such as the spherical surface of the end fitting that contacts the electrode. It eliminates the need for re-quenching and tempering treatment at the same time, and by blocking contact with air, it is possible to eliminate the generation of thermal discoloration (temper color) and oxide scale of at least the part immersed in water, and enhance the quality value. Due to welding in water, which has a higher electrical conductivity than air, it prevents melting and loss of the end fittings and electrodes due to sparking during welding, which stabilizes the quality and the end fitting side electrode Can be used for a long time and with the made,
Since the end fitting side electrode is water-cooled, the temperature rise of this electrode can be suppressed, the generation and adhesion of electrically insulating oxide scale can be prevented, and defective conduction can be eliminated.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view showing a case where the present invention is used for manufacturing a valve-acting push rod. ,
2 is a view corresponding to FIG. 1 of the above-mentioned other embodiment of FIG.
4 is the same as FIG. 1 of the above-mentioned yet another embodiment of FIG.
FIG. 3 is a partially enlarged cross-sectional view showing a case where the present invention is used for manufacturing a ball joint for an axial plunger pump, and (1) in FIGS. 1 to 3 shows, for example, a pipe diameter of 15.0 m / m, meat A metal tube member (metal member) made of a material STKM having a thickness of 2.5 m / m. (2) is material SW
A steel end fitting (end fitting) having a curved concave surface (2 ′) or convex surface (2 ″) such as a spherical surface formed by a sphere made of RM or SWCH and the like, and having Hv65 on its surface in advance.
It is obtained by performing a hardening treatment of about 0 to 850.
Further, with the back side abutting against the peripheral edge portion of the pipe member (1), at least the concave surface (2 ') or the convex surface () on the end fitting side electrode (5) provided inside the water tank container (3). With the state of the water level surface (6) in which the 2 ") part is submerged in water, the resistance is welded and fixed by electric resistance welding as the shaft core is pressed downward. (4) Welding of the pipe member (1) The tube-side electrode is divided into two in the vicinity of the fixed portion and holds the pipe material, and (3 ′) and (3 ″) are an inflow cylinder port and an outflow cylinder port through which water in the water tank container (3) flows. The water level surface (6) is at least lower than the welded portion, and the convex surface (2 ″) or the end fitting side electrode (5) is at a position substantially submerged.

Next, a case where the ball joint is used for manufacturing an axial plunger pump will be described with reference to FIG.

In this embodiment, a spherical body (2a) as an end fitting having a diameter of 16 mm, which is made of SWRM and has a through hole (7) having an inner diameter of 2.5 mm and having a hardening treatment applied to the surface, has an outer diameter of 12 mm and a high height. A shoe (1a) as a metal member made of S10C consisting of a cylindrical protrusion (8 ') having a length of 2 mm and a ring (8 ") having an outer diameter of 30 mm and a height of 6 mm which is integrated with the cylindrical protrusion (8') is electrically connected to the end peripheral portion. In this case as well, the water level surface (6) is lower than at least the welded portion and the end fitting side electrode (5) is positioned so as to be substantially submerged in water.

Next, a method of manufacturing a push rod for a valve according to the present invention (as shown in FIG. 1) and a conventional method (as shown in FIG. 5).
Comparative measurement values of hardness on the end fitting surface are shown below. -Sample manufacturing conditions Metal tube member; material STKM12CEC, outer diameter 8.0 m /
m, wall thickness 1.2 m / m End fitting; material SWCH10, concave radius of curvature 4.0 m /
m Electrode material: Beryllium bronze Measuring instrument: Vickers hardness tester

[0011] A product free from thermal discoloration (temper color) was obtained in the part of the end fitting (2) engaged with the end fitting side electrode (5) submerged in water and near the welded part on the tube member (1) side.

[0012]

As described above, in the welding method of the end fitting having the wear-resistant sliding curved surface according to the present invention, the end fitting (2, 2a) which has been surface-hardened in advance is at least welded from the welded portion. Since the electrode is low and the end fitting side electrode (5) is welded by electric resistance in a state of being submerged in water, the heat generated at the welding and fixing part during welding can be immediately dissipated by cooling with water. It is possible to effectively prevent a decrease in hardness on the spherical surface or concave surface (2 ') or convex surface (2 ", 2" a) of the end fitting (2, 2a), and to perform quenching and tempering again with the end fitting. A standard hardness can be obtained without the need for treatment, and thermal discoloration (temper color) at least in the submerged part due to contact interruption with air.
To improve the quality value, and to prevent melting and loss of the end fittings and electrodes due to sparking during welding, which enables stable quality and long-term use of the end fitting side electrodes (5). Since the end fitting side electrode is water-cooled, the temperature rise of this electrode is suppressed to prevent the generation and adhesion of electrically insulative oxide scale, and it is possible to eliminate defective conduction, etc. It is a welding method of end fittings having.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view with a partial cutaway showing a case where the present invention is used for manufacturing a valve operating push rod.

FIG. 2 is a view corresponding to FIG. 1 of the same as another embodiment of FIG.

FIG. 3 is a view corresponding to FIG. 1 of the above description of yet another embodiment of FIG.

FIG. 4 is a partially enlarged sectional view showing a case where the present invention is used for manufacturing a ball joint for an axial plunger pump.

FIG. 5 is a partially cutaway vertical sectional view of an apparatus at the time of manufacturing according to a method for manufacturing a valve operating push rod of a conventional example.

[Explanation of symbols]

 1 Metal tube member 1a Shoe 2 End fitting 2a Sphere 2'Concave surface 2 ", 2" a Convex surface 3 Water tank container 4,5 Electrode 6 Water level surface

Claims (3)

[Claims] 1. A method of electrical resistance welding a steel end fitting having a curved surface whose surface is hardened to the end peripheral edge portion of a metal member by abutting the back side thereof and pressing the shaft downward. 2. The method for welding end fittings having a wear-resistant sliding curved surface, characterized in that the end fittings (2, 2a) are electric resistance welded in a cooled state in water. 2. The method of welding an end fitting according to claim 1, wherein the water level surface (6) is at least lower than the welded portion and the lower electrode (5) is substantially submerged. 3. The welding method for an end fitting according to claim 1, wherein the water in the water tank container (3) is circulated by inflow circulation or inflow discharge.