JPH0428883A - Method and device for lining bearing back plate with white metal - Google Patents

Abstract

PURPOSE:To form a white-metal lining layer on the surface of a bearing back plate with high adhesion, by irradiating the specified region on the surface of the back plate with a laser beam and simultaneously supplying finely powdered white metal. CONSTITUTION:The bearing back plate 1 with the surface previously blasted is moved in direction of the arrow B, the specified region R on the surface is irradiated with a laser beam 5 condensed by a condensing lens 2a, an inert shield gas such as Ar and He is supplied from an inlet 7 and injected from the gas injection port 6b of a shield unit 6 to enclose the region, and the fine powder 8 of white metal is simultaneously supplied to the region R from a vessel 9. The fine powder 8 is melted by the laser beam 5, and the lining layer 11 of white metal is stably formed on the surface of the back plate 1 in uniform thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for lining a bearing back metal with white metal.

[Prior Art] A bearing back metal is generally lined with white metal, and this white metal lining is performed by a casting method. This casting method involves thoroughly cleaning the bearing back metal, tin plating or solder plating, and then lining it with white metal by pouring casting or centrifugal casting. However, since the casting method results in a thick lining layer, machining is required to reduce the thickness after casting, and the lining composition has a lot of segregation, resulting in uneven adhesion of the white metal to the bearing backing metal. There was a problem with becoming.

Furthermore, when the bearing is subjected to an uneven load, the white metal lining layer 102 of the bearing back metal 101 is exposed as shown in FIG.
A local abrasion damage part 102a is generated in the area, and this damage part 10
2a will need to be repaired.

However, in the casting method, it is difficult to line only the damaged portion 102a with white metal, and the above repair requires lining the entire backing metal 101 with white metal after removing the entire white metal layer 102 once.

A lining method that solves various problems of such casting methods is proposed in Japanese Patent Application No. 46-46705. This method uses a plasma arc welding device, in which a bearing back metal 101 is placed on a roller 103 as shown in FIG. This boom 10
5 relative to the bearing back metal 101. As shown in FIG. 6, the plasma arc welding device 104 welds white metal filler wire 1 using a plasma arc.
07 and the surface layer of the bearing back metal 101 are melted to line the bearing back metal 101 with white metal.

The white metal lined in this way has an adhesion strength of at least 7.1 to 8.1 kg with the bearing back metal 101.
f/2, the average is 7.6 kgf/mm2, and sufficient adhesion strength can be obtained.

Moreover, since this plasma arc welding device 104 can perform local overlay lining, wear-damaged parts 102a of the white metal lining layer 102 as shown in FIG.
can be easily repaired. That is, the plasma arc welding apparatus 104 changes the energy distribution of the plasma arc by changing the setting values, for example, the curve 108A in FIG.
Or it can be changed to 108B. Therefore,
The length of the wear-damaged part 102a to be repaired, that is, the repair width D (
The energy distribution of the plasma arc is changed in accordance with Fig. 4). Specifically, as shown in FIG. 7, the width d of the plasma arc energy distribution at the energy level E necessary for overlaying is determined to approximately match the length D of the wear loss i#102a.

[Problems to be Solved by the Invention] However, in the lining method using the plasma arc welding device described above, since the white metal is a very brittle material, the filler wire 107 easily breaks or bends during the lining work. There was a problem in that the lining work was often interrupted. Further, even if the lining work is not interrupted, the bending of the filler wire 107 makes feeding of the filler wire unstable, resulting in defects in the white metal overlay. In order to prevent such breakage and bending of the filler wire, great care must be taken when feeding the filler wire to the plasma arc welding apparatus. This is necessary every time the bearing has a different size, and it greatly impairs work efficiency.

Further, since the energy distribution of the plasma arc is almost Gaussian as shown in FIG. 7, the center becomes hotter than the periphery, and the backing metal locally becomes excessively melted in this high temperature area. Due to this excessive melting, a large amount of components from the backing metal mix into the white metal build-up, and a brittle alloy layer is formed at the boundary layer between the white metal build-up and the bearing backing metal, which deteriorates the bearing characteristics and causes the white metal to melt. There is also the problem that the alloy layer tends to peel off at the built-up portion. Furthermore, excessive local melting of the backing metal causes distortion in the backing metal, which significantly reduces the durability of the bearing.

Such problems caused by the plasma arc energy distribution can be prevented or suppressed by vibrating the welding torch 109 of the plasma arc welding device 104 from side to side as shown by arrow A in FIG. However, since this welding torch 109 stops instantaneously at the left and right ends of its vibration, excessive local melting of the back metal occurs at these left and right end positions, and the same problem as described above due to local excessive melting occurs.

Furthermore, when repairing the wear-damaged part 102a of the white metal lining layer 102, the wear-damage part 102a
When the width of the plasma arc is large, the plasma arc becomes the energy distribution 108B shown in FIG. 7, and the energy density at the center becomes too high, resulting in the same problem as described above due to local excessive melting.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a lining method and apparatus that can prevent excessive local melting and can line white metal thinly and with sufficient adhesion strength without using filler wire.

[Means for Solving the Problems] In order to achieve this object, the first invention of the present application includes a supply step of supplying white metal powder to a predetermined area of a bearing back metal, and a laser beam is applied to the predetermined area or the vicinity thereof. The present invention is characterized by comprising an irradiation step of irradiating to melt the supplied white metal powder and lining the bearing back metal with white metal.

In this configuration, the white metal powder preferably has a particle size of 48 to 400 mesh.

Further, the bearing back metal is moved relative to the laser beam,
In the irradiation step, it is desirable that the laser beam be irradiated onto the predetermined region slightly in front of the bearing back metal in the moving direction. Further, in the supplying step, the white metal powder may be emitted into the beam of the laser beam and fall onto the bearing back metal through the beam.

A second invention of the present application includes a supply means for supplying white metal powder to a predetermined area of a bearing back metal, and a laser light source, and irradiates the laser light onto the predetermined area of the bearing back metal or its vicinity to produce the supplied white metal powder. The present invention is characterized by comprising an irradiation means for melting metal powder and lining the bearing back metal with white metal, and a moving means for relatively moving the laser beam and the bearing back metal.

This configuration includes a central transmitting part that is arranged at a small distance from the bearing back metal and transmits the laser beam, and an inert gas that is located around the central transmitting part and injects an inert gas to the bearing back metal. It is preferable to further include a shield unit having an injection hole.

[Operation] White metal powder is supplied to a predetermined area of the bearing back metal, and a laser beam is irradiated to the predetermined area of the bearing back metal or its vicinity to melt the supplied white metal powder and line the bearing back metal with white metal. do.

[Example] Hereinafter, an example of a method and apparatus for lining a bearing back metal with white metal according to the present invention will be described with reference to FIGS. 1 to 3.

In FIG. 1, a bearing back metal 1 made of mild steel whose upper surface has been previously blasted is movable in the direction of arrow B by a drive device (not shown). The lens barrel 2 disposed above the bearing back metal 1 has a built-in condensing lens 2a.
A reflecting mirror 3 is arranged above a. This reflector 3
reflects a laser beam 5 from a high-output carbon dioxide laser oscillator 4 with a rated output of several kilowatts or more onto a condenser lens 2a. A shield unit 6 is disposed close to the upper surface of the bearing back metal 1 between the bearing back metal 1 and the lens barrel 2. This shield unit 6 is a ring-shaped hollow body, and a transmission window 6a through which the laser beam 5 passes is formed in the center, and a large number of shield gas ejection holes 6b are bored in the lower wall of the hollow chamber surrounding the transmission window 6a. has been done. The laser beam 5 that has passed through the condenser lens 2a is transmitted through the transmission window 6a and irradiates a predetermined area R of the back metal 1.

A shield gas introduction lower is attached to the shield unit 6, and an inert gas such as argon, helium, nitrogen, etc. is introduced through this shield gas introduction lower. A container 9 containing the white metal powder 8 is supplied with the white metal powder 8 via a powder supply pipe 10 penetrating the shield unit 6.
is emitted in the vicinity of the predetermined irradiation area R, specifically, slightly backward in the back metal moving direction B, for example, approximately 10 degrees backward. The white metal powder 8 is suitably a spherical powder of 48 to 400 meshes. The reason why the particle size range of the white metal powder 8 was determined as described above is as follows. That is, to powderize metal, a method that utilizes a melting phenomenon, such as an atomization method or a rotating electrode method, is usually used. However, since the solidification temperature of white metal is very low at around 3009C, white metal powder larger than 48 mesh will not become spherical in the atomization method or rotating electrode method, but will become flaky or lava-like. Performance will be significantly degraded. Furthermore, spherical powder cannot be obtained by mechanically crushing white metal ingots. On the other hand, powders finer than 400 mesh tend to solidify within the powder container 9 and supply pipe 10, resulting in lower supply performance.

Next, the operation of this embodiment will be explained.

The shielding gas introduced from the shielding gas introduction lower is injected from the ejection hole 6b so as to surround the laser irradiation region R. After this, the laser oscillator 4 emits laser light 5. After this laser beam 5 is focused on the upper position of the backing metal 1 by the condensing lens 2a, it irradiates an irradiation area R of a predetermined spread and melts the surface layer of the backing metal 1 very slightly. At the same time, white metal powder 8 is discharged from the supply pipe 10 slightly in front of the irradiation region R. When the discharged white metal powder 8 reaches the irradiation area R as the back metal 1 moves, it is melted by the laser beam 5 and forms a white metal lining layer 11. As shown in FIG. 2, the laser beam 5 has a substantially uniform energy density over the entire irradiation area R, so that the backing metal is not overly melted locally and the composition is almost uniform over the entire irradiation area. A lining layer 11 is obtained. Note that when the temperature of the backing metal 1 increases significantly, the backing metal 1 is cooled from below.

Preferred numerical examples for this embodiment are as follows.

That is, the laser output of the laser oscillator 4 is 4 to 15 KW, the focal length of the condenser lens is 254 or 381 degrees, the size of the irradiation area R (the diameter of the laser beam on the back metal 1) is 5 to 30 mm, and the movement of the back metal 1 is The speed is 300-1500+am/min and the powder feed rate is 60-200 g/min. These values indicate that the energy density on the surface of backing metal 1 is 5 to 15K.
It is desirable to select J/cd, thereby suppressing thermal distortion of the backing metal 1 and obtaining a lining layer 11 with sufficiently high adhesion strength and no peeling.

When an adhesion strength test was conducted on the lining test piece prepared according to this numerical example, the minimum value was 7.5)cgf/
mm2. Maximum value 9.8) cgf/mm2.

Average 8.5kgf/mm2. Standard deviation 0. 5kgf/
It was mm2. This is white metal (WJ-2
) Comparable to the tensile strength of the material itself, 8.3 kgf/mm2.

FIG. 3 shows another embodiment of the invention, in which a powder supply tube 10 passes through the wall of the lens barrel 2 and emits white metal powder 8 into the laser beam 5. In FIG. This ejected powder 8 passes through the laser beam 5 and falls directly onto the irradiation area R. This example is particularly effective for lining a curved back metal or for local lining during repair, since there is no particular restriction on the direction in which the lining builds up. On the other hand, since the white metal powder is directly emitted into the laser beam 5, a part of it may vaporize before reaching the back metal 1 and adhere to the lens 2a, reducing its transmittance. Not suitable for use.

The present invention is not limited to the mild steel back metal of the above embodiment, but can be similarly applied to a copper flat plate back metal used in thrust bearings. In this case as well, the energy density on the surface of the back metal may be determined to be 5 to 15 KJ/cd.

[Effects of the invention] As is clear from the above description, according to the present invention, white metal powder is supplied to a predetermined area of the bearing back metal, and
In order to line the bearing backing metal with white metal by irradiating the light onto a predetermined area of the bearing backing metal or its vicinity and melting the supplied white metal powder, the lining layer is made thinner and its adhesion strength is increased. In addition, by using white metal powder, it can be widely applied to bearing back metals of various sizes.

Furthermore, by using a laser beam, it is possible to prevent excessive melting locally, thereby preventing deterioration of bearing characteristics, peeling of the lining layer, and thermal distortion of the backing metal.

Furthermore, laser light generally has a low absorption rate on solid metal surfaces, but in the present invention, since the white metal is not powdered, the absorption rate is significantly higher than that of wire or bulk white metal. Therefore, it is possible to avoid increasing the size of the laser light source.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the method and apparatus for lining a bearing back metal with white metal according to the present invention, and FIG.
The figures are a diagram showing the laser beam of Figure 1 and its energy distribution, Figure 3 is a schematic diagram showing another embodiment of the present invention, and Figure 4 is a diagram showing the laser beam and its energy distribution.
The figure is a cross-sectional view showing the abrasion damage caused in the lining layer of the bearing back metal, Figure 5 is a schematic diagram showing a conventional lining device, and Figure 6 is an enlarged view of the plasma arc welding device shown in Figure 5. The cross-sectional view shown in FIG. 7 is a graph showing the energy distribution of the plasma arc. DESCRIPTION OF SYMBOLS 1...Bearing backing metal, 4...Laser oscillator, 5...Laser light, 6...Nold unit, 8...White metal powder, B...Movement direction of bearing backing metal Applicant's agent Sato - Itezu Diagram Middle - Tanichi Misenchimanzu Inotsu Mansozu

Claims (2)

[Claims] 1. A supplying step of supplying white metal powder to a predetermined area of the bearing back metal; and an irradiation step of irradiating the predetermined area or its vicinity with a laser beam to melt the supplied white metal powder and lining the bearing back metal with white metal. A white metal lining method for a bearing back metal comprising: 2. A supply means for supplying white metal powder to a predetermined area of the bearing backing metal, and a laser light source, the laser beam is irradiated to the predetermined area of the bearing backing metal or its vicinity to melt the supplied white metal powder, thereby producing the bearing. A device for lining a bearing back metal with white metal, comprising: irradiation means for lining the back metal with white metal; and moving means for relatively moving the laser beam and the bearing back metal.