JPS60174842A - Bearing material for turbo charger - Google Patents

Abstract

PURPOSE:To provide a bearing material for a turbo charger having the higher resistance to wear and seizure than the bearing material made of the conventional lead bronze by consisting said material of respectively prescribed ratios of Cu, Zn, Al and further 1-3 kinds among Ni, Fe, Ti, Pb, Mn, Si and Zr and specifying surface length, etc. CONSTITUTION:The above-described bearing material contains, by weight %, 55-65 Cu, 25-35 Zn, 2-6 Al and consists further of alloy components contg. at least 1-3 kinds among 0.2-3 Ni, 0.5-4 Fe, 1-2.5 Ti, 2-10 Pb, 2-4 Mn, 0.5-2 Si and 0.5-2 Zr. The bearing material is crystallized with the intermetallic compd. particles having 5-30mu max. length and >=400 Vickers hardness on the surface at 3-15% area rate. Since such bearing material contains prescribed amt. of Ni, Fe, Ti, Zn, Mn, etc., the intermetallic compd. consisting of these components is produced and is precipitated in a needle-like or lump state into the base alloy by selecting optimum conditions for production, cooling, etc. The resistance to wear is thus improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a turbocharger (turbocharger).
floating bearings used in
ingbearing) material.

(Prior art) Floating bearings used in the bearings of turbochargers installed in internal combustion engines reach a high temperature of around 300°C due to heat conduction from the turbine immediately after the internal combustion engine stops operating, so the bearing surface The attached lubricating oil, engine oil, is heated above its heat-resistant temperature. As a result, table problems such as the following may occur. That is, (1)
Corrosive acidic substances are produced in engine oil, which selectively corrode, for example, lead contained in bearing materials, increasing wear on the bearings.

(2) The engine oil deteriorates and deposits are formed in the oil tank that supplies lubricating oil to the bearings.
Precipitates) form and block the oil inlet, causing an oil film breakage.
Insufficient lubrication increases wear on the chive line log.

(3) Abrasion of the bearings may occur due to friction with flakes of deposits formed in the above process or metal chips remaining on the surface of the engine body or turbocharger due to improper cleaning. growing.

When bearing wear increases, turbine wheel A/
The eccentricity of the rotating shaft of the turbine wheel (turbine wheel) increases, so the turbine wheel and turbine housing (
This may cause problems such as abnormal noise or damage to the turbine wheel.

Conventionally, lead bronze containing copper, tin, and lead (for example, LB (j, LBC4°LBC5)) has been mainly used as a material for 70-length bearings in turbochargers, but it has poor wear resistance and lubrication resistance. The subsequent seizure resistance was not fully satisfactory.

(Object of the Invention) The present invention is intended to solve the problems in the prior art described above, and its purpose is to provide a material with better wear resistance and seizure resistance than conventional lead bronze turbocharger bearing materials. Excellent turbocharging. The objective is to submit bearing materials for bearings. (Structure of the invention) That is, the bearing link material for a turbocharger of the present invention is
Copper 55 to 65%, zinc zs to 55% by weight,
Aluminum 2 Shiro T.

Furthermore, at least 2 to 5% of nickel α, 5 to 4% of iron, 1 to 2.5% of titanium, 2 to 10% of lead, 2 to 4% of manganese, 5 to 2qI of silicon, and 5 to 2% of zirconium It is characterized by having an alloy component containing one or three types of impurities and the remainder, and crystallized on the surface of intermetallic compound particles with a maximum length of 5 to 30 μ and a Vickers hardness of 400 or more at an area ratio of 3 to 15. shall be. A preferred bearing material has a base material containing 55 to 65 inches of copper, 25 to 35 inches of zinc, and 2 to 611 II of aluminum, and further contains 2 to 4% iron and 1.5 to 2-5 inches of titanium. Examples include alloys in which 2 to 10 parts of lead are added or in addition to the above components.

Another preferable bearing material has a composition of copper 5 by weight.
Examples include alloys in which 2 to 3% of nickel + 1L and 1 to 2% of titanium are added to a base material containing 5 to 65 inches of zinc, 25 to 35 inches of zinc, and 2 to 6 inches of aluminum.

Another preferable bearing material has a base material containing 55 to 65% copper, 25 to 55% zinc, and 2 to 6 qb of aluminum, and further contains 2 to 3% nickel alpha, 2 to 4 qb manganese, and silicon. 115
Examples include alloys to which 1 to 2 chlorides are added.

Another preferable bearing material has a base material containing 55 to 65% copper, 25 to 55% zinc, and 2 to 6% aluminum by weight, and further contains α2 to 5% nickel, α5 to 2% iron, Silicon (L5 to 2%
Examples include alloys to which 5 to 2% of zirconium α is added, or 2 to 10% of lead is added in addition to the above components.

The bearing material of the present invention includes nickel, iron, titanium, zinc,
Because it contains a certain amount of manganese, silicon, etc., hard intermetallic compounds are formed that are similar to these components, and by optimally selecting manufacturing and cooling conditions, they can be precipitated in the form of needles or lumps during the synthesis of the base material. be able to. This intermetallic compound has a Vickers hardness (By) of 400 or more, and by uniformly dispersing the compound with an appropriate size and maximum length, it improves the wear resistance of the base alloy. can be improved. The maximum length is about 5 to about 30μ, especially 1
A thickness of about 5μ is preferable. Further, the area ratio where the intermetallic compound crystallizes is preferably 3 to 15 inches. Therefore, by using this alloy, a bearing with excellent wear resistance can be obtained.

Further, the wear resistance of the bearing material can be further improved by utilizing the characteristics of the bearing material of the present invention. That is,
After polishing the sliding surface of a bearing material formed into a desired shape, such as a cylindrical shape, the sliding surface is etched using an appropriate etching agent, such as various acids or salts, to form particles of intermetallic compounds such as iron and titanium. Since it is difficult to corrode, it remains exposed on the sliding surface. For this reason, the sliding surface has a structure with continuous or intermittent recesses, and by filling the recesses with lubricating oil to form an oil sump, lubricity is increased and wear resistance is improved. In particular, it is possible to reduce the initial scuff (S Cu "s") at the time of startup.If the depth of the recess, that is, the exposed height of the intermetallic particles is too large, the intermetallic particles will peel off. Since a sufficient lubricating effect cannot be obtained if the thickness is too small, it is recommended that α be approximately 5μ to approximately 5μ, preferably approximately 1μ to approximately 3μ.

Another method for obtaining the same effect as above is to arrange grooves in the form of grooves at predetermined intervals along the circumferential direction on the inner and outer peripheral surfaces of a cylindrical bearing material. It's okay. Furthermore, when the surface etc. are precision-machined to make a final product bearing, it is not only effective to store lubricating oil such as engine oil, but also to separate the sliding surface of the bearing along its axial direction. Therefore, even if sludge is generated on each divided sliding surface due to engine oil deterioration, the adhesion area is small and the sticking power is weakened. For this reason, the sysludge is easily broken by the rotation of the bearing, eliminating problems such as sticking to the sliding surface.

In addition, in the case of the bearing material of the present invention, hard intermetallic compound particles are exposed on the sliding surface, which is also effective in scraping off sludge64), and together with the effect of the grooves, it is extremely effective in removing sludge. Stops things that are difficult to generate. Furthermore, by providing grooves, the flow rate of engine oil flowing in the axial direction of the bearing when the turbocharger is operating is increased, increasing the lubrication and cooling effect and suppressing the rise in bearing temperature, thereby reducing the generation of sludge and bearing wear. can be reduced. It is even more effective if the sliding surface is etched and grooves are provided in combination.

The size of the cylindrical bearing, i.e. the height of the cylinder, the inner diameter,
The outer diameter is optimally selected according to the turbocharger. A hole having a desired size and shape may be formed in a part of the cylindrical side surface for the purpose of preventing deformation, increasing cooling efficiency, supplying engine oil, etc.

The cross-sectional shape of the groove can be various shapes, such as a 7-shape, a U-shape, a rectangle, or a semicircle. In addition, the groove spacing, width, and depth are optimally selected taking into account the strength of the bearing, the amount of engine oil retained, workability, etc.; however, for turbocharger bearings used for normal purposes, the groove spacing is Approximately 1
About 5W! The width of x1 should be about 15 m to 5 cm, and the depth should be about 5 m to about 5 cm.

<*Example) The present invention will be explained in further detail in the following example. Note that the present invention is not limited to the following examples.

Example 1: Copper (Cu) 55 to 65% by weight, Zinc (ZrB) 2
5 to 35% by weight of aluminum (AI), 2 to 6% by weight of aluminum (AI), 1 tlb of iron (Fe) 2 to 4 times, and 5 to 2.5% of titanium (Ti) by weight. After melting at 1000° C. and casting at around 1000° C., the mixture was cooled to room temperature to obtain bearing material 1 for a turbocharger of the present invention.

Example 2: In addition to the same amounts of copper, zinc and aluminum as the raw materials of Example 1, nickel (Ni) (L2 to 3% by weight and titanium 1 to 2% by weight) were added and the same method as in Example 1 was carried out. Yoshi bearing material 2 was obtained.

Example 3: Copper, zinc, aluminum and nickel were added in the same amounts as the raw materials of Example 2, and 2 to 4% by weight of manganese (Mn) was added.
, by adding 5 to 2% by weight of silicon (St) α
Sea bearing material 3 was obtained in the same manner as above.

Examples 4 to 7: Sea bearing materials 4 to 7 were obtained in the same manner as in Example 1 except that the additive components were changed. 'Chemical components of the bearing materials for turbochargers of the present invention obtained in the above-mentioned Example Layers to 7 and conventional materials for comparison, and wear resistance of bearings manufactured using these;
The seizure occurrence time (seizure resistance) is summarized in the table. The wear resistance shown in the table was measured at relatively low rotation speeds using the LFW-1 wear tester.
It shows the wear depth of various bearing materials under low loads, and those with small values show erosion. In addition, assuming the anti-seizure condition shown in the table, a condition of poor lubrication, which is a problem specific to bearings for turbochargers, we conducted a break-in operation at low load and high rotation under lubrication using a friction and wear tester belonging to Mechanical Testing. It shows the time from when lubrication is stopped until seizure occurs. The longer the time, the better.

As is clear from the table, the bearing material of the present invention has a much smaller wear depth and significantly improved wear resistance than conventional lead bronze. In addition, the time required for seizure to occur has become longer, and the seizure resistance has also been improved. The reason why the bearing material of the present invention has excellent wear resistance is that hard intermetallic compound particles are crystallized in the base material, and A390 in the table is a material with a similar structure. High-silicon aluminum alloys are representative. However, although this alloy has excellent wear resistance, it has low seizure resistance under conditions of insufficient lubrication. this is,
This is because the base material is aluminum (AI), which has a low heat resistance temperature, and is likely to undergo plastic flow due to an increase in the temperature of the friction surface due to poor lubrication. The material of the present invention is superior because the base material is copper (Cu), which has a higher heat resistance temperature than aluminum and is less likely to have laminar flow. The reason why conventional lead bronze (LBC) and 4.5 has excellent seizure resistance is because it contains lead (Pb), as can be seen when compared with the comparative material PBP. This is because it is eluted by frictional heat and exhibits a lubricating effect. However, the wear resistance is poor because hard intermetallic compound particles are not crystallized in the alloy structure as in the material of the present invention. Adding lead to the material of the present invention also produces the same effect as described above, and the seizure resistance is further improved.

FIG. 1 is a partially enlarged sectional view of the surface of the bearing material for a turbocharger according to the present invention after polishing and etching.

After polishing the sliding surface of the cylindrical bearing material,
Sodium chloride t05g/l, ammonium chloride 30
Etching was carried out for several minutes at room temperature using an aqueous solution containing 1 to 5 g/L, and the intermetallic compound particles 2 were exposed on the surface of the base material 1 to a depth of 1 to 5 μm.

FIG. 2 is a cross-sectional view of an embodiment of a bearing manufactured using the bearing material for a turbocharger of the present invention in which grooves are provided on the sliding surface. The bearing 5 for the turbocharger has 10 inner diameters and 16 outer diameters, is it an island? It has a simple cylindrical shape (1) and has six holes 4 in its axial center. In addition, on the inner and outer circumferential sides, there are 1 m + 11 in width at 3W intervals along the circumferential direction.
The groove 5 has a V-shaped cross section and has a depth of 1°.

When such grooves 5 are provided, the contact area decreases, so the pressure (surface pressure) per unit area is large, and bearings made from conventional materials increase wear, which is a problem. Since the bearing material of the present invention has wear resistance, even if the surface pressure increases, the wear does not increase at all, causing no problem.

FIG. 3 is an enlarged cross-sectional view of the portion (2) surrounded by the dashed-dotted line in FIG.

(Effects of the Invention) As described above, the bearing material for turbochargers of the present invention has no intermetallic compound particles on the surface having an appropriate average particle size and is much harder than the base alloy. It has improved wear resistance and seizure resistance compared to other materials such as lead bronze bearing materials for turbochargers, and has a significant effect on improving the reliability and quality of turbochargers.

[Brief explanation of the drawing]

Fig. 1 is a partially enlarged sectional view of the surface of the turbocharger bearing material of the present invention after polishing and etching, and Fig. 2 shows the use of the turbocharger bearing material of the present invention with grooves provided on the sliding surface. FIG. 3 is an enlarged sectional view of a portion (2) surrounded by a dashed line in FIG. 2. In the figure, 1...Base material 2...Intermetallic compound particles 3...Bearing for turbocharger '4...Hole 5...Groove Patent Applicant Toyota Motor Corporation R Employee Figure 2 1 Figure 30

Claims (3)

[Claims] (1) Contains 55 to 65 inches of copper, 25 to 35 inches of zinc, 2 to 69K of aluminum, and 2 to 3 inches of nickel, iron (L5 to 4%, titanium 1 to 15%, lead 2 to 10 inches, 2 to 4 manganese,
It is not an alloy component containing silicon α5 to 2, zirconium (at least one or three of L5 to 2, and the remaining impurities), and the maximum length on the surface is 5 to 30.
A bearing material for a turbocharger, characterized in that intermetallic compound particles having a Vickers hardness of 400 or more are crystallized in an area ratio of 6 to 15. (2) The bearing material for a turbocharger according to item 1, in which the surface is polished and then the surface is etched to remove rotten water. (3) The bearing material for a turbocharger according to claim 1, wherein grooves in the form of grooves are provided in the circumferential direction on the inner peripheral surface and the outer peripheral surface of the bearing material formed into a cylindrical shape.