JPH0434628B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method for manufacturing a copper-lead bearing material, and more specifically, a composite bearing material in which a copper-lead bearing alloy is adhered to a back metal. The present invention relates to a method of manufacturing and a manufacturing apparatus.
The present invention aims to improve the manufacturing method of sliding bearings used in all industrial fields including bearings for automobiles, and to provide a bearing material with excellent performance.

Prior Art A method for mass-producing composite bearing materials is to deposit a desired bearing alloy on the strip as a bearing layer during the process of winding a strip-shaped backing metal from an uncoiler to a coiler. The method can be divided into the joint pressure welding method, the joint sintering method, and the joint casting method. In the joint pressure welding method, a strip-shaped aluminum alloy, which is a bearing alloy, is generally pressure-bonded onto a strip. On the other hand, in the joint sintering method and the joint casting method, a copper-lead bearing alloy or the like is generally deposited on a back metal strip.

Solid sintering is a process in which copper-lead bearing alloy powder is sprinkled onto the strip being threaded and the powder is heated in a sintering furnace with a suitable protective atmosphere. The main point of this method is to cause a reaction between the powder and the strip. Generally, sintering is performed twice, and between the two sinterings, the powder and strip are rolled down with a reduction roll to form the sintered layer to a predetermined size and to densify it. The copper-lead alloy bearing layer of composite bearings manufactured by the solid-state sintering method has residual pores peculiar to the sintering reaction, so the structure is not sufficiently densified, especially in recent years with high-performance internal combustion engines. There is a problem in that the fatigue strength is insufficient for bearings used under high loads and high speeds. In addition, since several tens of minutes to several hours of heating time is required for the sintering reaction to proceed completely in the joint sintering method, it is inevitable that the lead particles in the copper-lead alloy tend to become coarser. , This also causes the tissue to become insufficiently dense.

In the joint sintering method, it is also known to pass the composite material strip through a lead bath after sintering, thereby filling the voids in the copper-lead bearing alloy layer with lead. However, the surface tension of molten lead is high,
In addition, since the pores are minute, lead does not penetrate deeply into the pores. Therefore, this method cannot be said to be perfect.

According to British Patent No. 437199, which describes a solid casting process, in order to produce a composite bearing strip with Kelmet alloy deposited on a strip, the strip is first placed in a copper bath while being wound from a coiler to an uncoiler. The strip is then heated to near the casting temperature of the next step by passing through the strip, and then the Kelmet alloy is cast onto the strip, followed by passing through a furnace with a reducing atmosphere to prevent oxidation of the cast metal. A method is known in which the cast metal is rapidly solidified by water cooling from the back side of the strip.

Furthermore, according to Japanese Patent Publication No. 39-22498, in order to manufacture a composite bearing strip in which a lead-based bearing alloy is coated on a strip, a coil of a strip of rolled steel is wound from a coiler to an uncoiler. It is known to pass the strip successively through a cleaning bath, a reducing atmosphere furnace, a casting section, a cooling section, a milling cutter and a finishing roll. In this method, the surface of the rolled steel material is first cleaned and activated by solvent degreasing and atmospheric heating to adjust the surface conditions for adhering the cast metal in the next step, then casting is performed and immediately quenched. The lead-based alloy is solidified as a thin layer with a fine structure.

Although the above-mentioned solid casting method produces a dense copper-lead bearing alloy layer due to the unique structure of casting, it requires a power source for melting and a heating furnace with the capacity to pour the metal into the entire long strip. , a stopper device to control the amount of molten metal poured, or a furnace tilting mechanism, etc. are indispensable.Furthermore, when ordinary rolled steel is used as the backing metal, a stopper device to control the amount of molten metal poured, or a furnace tilting mechanism, etc. Since a bathtub facility or an atmosphere heating furnace is required, the joint casting method has the disadvantage of high equipment investment cost. Furthermore, in the solid casting method, the thickness of the copper-lead bearing alloy layer is primarily determined by the amount of molten metal applied per unit time and unit area, which is determined by the amount of molten metal poured and the strip passing speed. It is not always easy to obtain the desired uniform layer thickness by controlling the stopper or tilting mechanism, and therefore, in the conventional method, after rapid cooling, a considerable amount of the surface of the cast alloy layer is removed by skyping to the desired layer thickness. It's being scraped off. This becomes a major factor in reducing product yield.

Problems to be Solved by the Invention The present invention provides a composite bearing material in which a copper-lead bearing alloy layer is adhered to a back metal, which has the same structural density as a bearing alloy layer obtained by a solid-state casting method. The object of the present invention is to provide a manufacturing method without using extremely complicated and expensive equipment.

Furthermore, it is an object of the present invention to provide a composite bearing material manufacturing apparatus that can carry out the above method by providing some additional equipment without substantially modifying existing equipment for carrying out the joint sintering method. do.

Means for Solving the Problems The method according to the invention is characterized by sequentially performing the steps of scattering copper-lead bearing alloy powder on a back metal, sintering it, and melting the obtained sintered layer. .

In the present invention, the copper-lead bearing alloy is a copper-based bearing alloy whose main component is copper, contains 5 to 20% lead, and further contains antimony, zinc, tin, etc. as necessary. A characteristic of the composition is that the lead particles tend to become coarse. Also, copper-
The lead bearing alloy powder may be of normal particle size, particularly -250 mesh is used.

The above-mentioned copper-lead bearing alloy powder is spread on a normal back metal material, applied to the entire surface of the back metal, and then sintered.
In the present invention, this sintering is performed as a preliminary step to the next step of melting. That is, in the usual continuous sintering method, a desired copper-lead bearing alloy layer is formed by sintering, but in the present invention, sintering is first performed and then melting is performed to obtain a composite bearing material. As a first step, sintering is performed to achieve the characteristics required for a bearing to some extent by bringing the particles of the dispersed copper-lead alloy powder into close contact with each other and between the powder and the metal backing. At the same time, this is to achieve a state of particle dispersion in which the reaction between the particles of the copper-lead bearing alloy powder progresses significantly during the next step of melting.

According to the invention, after sintering is complete, the copper-lead alloy sintered layer is melted. Through this melting process, the voids remaining between the copper-lead bearing alloy powder particles upon completion of sintering are filled with molten metal, resulting in a bearing layer with a dense structure.

In the method according to the present invention, the desired effect can be obtained even if the entire copper-lead sintered alloy or only its low melting point phase is melted in the melting step. Generally, in the method according to the present invention, the degree of melting of the copper-lead bearing alloy can be adjusted to the degree necessary for filling the voids by adjusting the heating conditions. On the other hand, in the joint casting method, the casting temperature is set considerably higher than the melting point of the copper-lead bearing alloy in order to avoid troubles during the casting operation. In the present invention, the degree of melting of the copper-lead bearing alloy is allowed to be adjusted as described above.
There is no problem if the molten alloy is allowed to cool after melting, but if the degree of melting is large, especially if the entire metal is melted, a more dense structure can be obtained by rapidly cooling the molten alloy by injecting water or gas from the back side of the metal backing. .

The heating means for performing the melting in the method according to the present invention is arbitrary, and high frequency induction heating, electric resistance heating, laser heating, electron beam heating, flame or plasma spraying, etc. can be employed. However, in order to avoid oxidation of the copper-lead alloy during melting, flame spraying is not recommended, and if the heat input rate is slow, lead particles may become coarse during heating depending on the lead content. Electric resistance heating, which is unsuitable for rapid heating, is also not preferred because it increases . Furthermore, laser and electron beam heating require a scanning mechanism for scanning the laser beam or electron beam.

High-frequency induction heating is preferable because it does not have the above-mentioned disadvantages, but since the copper-lead molten alloy tends to swell slightly due to electromagnetic force, it is important to adjust the heating conditions.

The composite bearing material manufacturing apparatus according to the present invention operates from a tank that sprays copper-lead bearing alloy powder onto the strip being threaded, from an uncoiler that winds a coiled strip to a coiler that winds the strip. The method is characterized in that a sintering furnace, high-frequency induction heating means, and cooling means are sequentially provided to sinter, melt, and cool the copper-lead bearing alloy powder during sheet threading.

The apparatus according to the present invention is characterized in that a high-frequency induction heating means for performing melting after sintering and a means for cooling the molten sintered layer are added to a conventional apparatus for carrying out a continuous sintering method.

Effects The effects of sintering and melting in the present invention will be explained in comparison with the effects of sintering and melting in the conventional solid sintering method.

Sintering in the present invention does not have the function of forming the final bearing layer structure, but is performed as a precursor to melting. Therefore, the sintered layer structure obtained by sintering in the present invention may have pores,
In addition, the sintered layer may have a higher porosity than the sintered layer obtained by the conventional continuous sintering method. However, if the degree of sintering is extremely low, the reaction between the copper-lead bearing alloy powder particles during the melting process will be insufficient, which is not preferable. On the other hand, according to the conventional solid state sintering method, the sintered structure with pores remains in the product as it is.

Melting in the present invention substantially eliminates pores peculiar to the sintered structure by further melting the copper-lead bearing alloy powder particles that have undergone a sintering history. On the other hand, in the joint casting method, the copper-lead alloy is in a molten state when it is applied to the backing metal, so there is no problem of voids in the first place, and therefore, the molten metal is formed once. It also does not have the effect of eliminating the pores that have been formed.

Note that the copper-lead bearing alloy layer prepared according to the present invention having the above-mentioned effect has no pores and has a sintered structure (4
It exhibits a structure closer to that of a cast structure than that shown in Figure A).

Furthermore, since the melting in the present invention only needs to be carried out to the extent that the pores disappear, it is not necessary to completely melt the copper-lead alloy, and the temperature can be selected within a wide range. The sintered alloy layer is quite firmly thermally bonded onto the backing metal, and because there is little movement or flow during heating, it also has the effect of suppressing local layer thickness changes during melting. Furthermore, according to the melting in the present invention, by selecting powder with fine particle size in the sintering process and performing rapid heating and rapid cooling by appropriately selecting the sintering and melting temperature and time, it is possible to obtain a fine final structure. It is possible. On the other hand, in the joint casting method, it is possible to adjust the fineness of the structure by changing the cooling rate, but in the casting process in which molten metal is poured and solidified, segregation of lead, etc. occurs even if various melting conditions are devised. It is unavoidable that lead particles may coarsely crystallize in a copper-lead bearing alloy containing a large amount of a low-melting point metal that tends to melt.

Examples of the present invention will be described below.

Example In Fig. 1, 1 is a strip of SPCC or the like used as a backing metal, 10 is an uncoiler that winds the strip, 11 is a coiler that unwinds the wound strip, and 12 is a copper alloy powder 2 being passed through. This is a tank for spraying on strip 1 of The copper-lead alloy powder 2 sprinkled on the strip 1 is sintered in a sintering furnace 3 as the strip 1 is passed through.
Sintering is typically performed at 700-900℃ under a reducing atmosphere for 10~
It will be held for 30 minutes. After sintering, the strip 1 coated with a copper-lead alloy layer (not shown) is passed through a high frequency induction heating furnace 5. Here, the copper-lead alloy layer is 1000
The temperature is raised to around 1000°C in about a few tens of seconds, and this 1000°C
After being melted for a short period of time at around
It will cool down to room temperature in a few minutes. 13 is a nozzle that sprays water or oil from the back side of the strip 1.
9 is copper formed through sintering, melting, and cooling.
It is a lead alloy layer.

FIG. 2 uses the same reference numerals as FIG. 1 to illustrate another embodiment of the invention. In this embodiment, a reduction roll 4 is arranged between the sintering furnace 3 and the high frequency furnace,
The thickness of the sintered layer is being adjusted.

The main parts of the high frequency furnace shown in FIGS. 1 and 2 are shown in FIG. A copper-lead alloy layer 14 sintered and bonded onto the strip 1 is passed through a coil 15 during strip threading. The shape of the coil may be any shape, such as circular or rectangular, as long as it allows the coil to pass through the strip 1. If the strip 1 has a width of 150 mm and a thickness of about 2 mm, and the thickness of the copper-lead alloy layer 14 is 0.3 mm, the power source (not shown) that energizes the coil 15 has a capacity of 16 KW and a frequency of 3 KHz.
It's fine to use one. The threading speed that determines the amount of power input to the strip 1 is preferably 0.25 to 0.1 m/min when the total length of the coil 15 is 500 mm and the pitch is 20 mm.

Note that if the copper-lead alloy layer 14 remains in a molten state for a long time, it is desirable that the atmosphere in the high-frequency heating furnace 6 be reduced.

Effects According to the present invention, a copper-lead bearing alloy layer having the same structural density as the conventional solid-state casting method can be obtained by heating for a short time after solid-state sintering.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams of embodiments according to the present invention, Figure 3 is the main part of a high frequency furnace for explaining high frequency induction heating, and Figure 4 is an illustration of a high frequency furnace manufactured by the method according to the present invention. These are metallurgical micrographs (100x magnification) showing the structure of the copper-lead alloy layer of the composite bearing material before and after melting, respectively. 1... Strip, 2... Copper-lead alloy powder, 3
... Sintering furnace, 5 ... High frequency induction heating furnace, 6 ... Cooling furnace.

Claims (1)

[Scope of Claims] 1. A method for producing a copper-lead bearing material, which comprises sequentially performing the steps of dispersing copper-lead alloy powder onto a back metal, sintering it, and melting the obtained sintered layer. 2. From the powder storage tank configured to spray copper-lead bearing alloy powder onto the strip being threaded by an uncoiler that winds the coiled strip and a coiler that winds the strip, , sequentially, sintering furnace, high frequency induction heating means,
A copper-lead bearing material manufacturing apparatus, which is provided with a cooling means and performs sintering, melting, and cooling of copper-lead bearing alloy powder during sheet passing.