JPH0810012B2 - Bearing material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a bearing material having a backing metal and a lining layer made of an Al bearing alloy having high strength at high temperature, that is, having a small decrease in hardness even at high temperatures.

"Conventional Technology" Conventionally, a bearing material (for example, Japanese Patent Publication No. 58-14866) in which a backing made of a steel plate and a lining layer made of an Al bearing alloy having a high temperature hardness are pressure-bonded is already known. Bearing materials in which an intermediate layer made of Al or an Al alloy is interposed between a backing steel plate and a lining layer made of an Al bearing alloy (for example, Japanese Patent Publication Nos. 37-15014 and 44-28174) are already known. ing.

The aluminum bearing alloy of Japanese Patent Publication No. 58-14866 is
Sn3.5〜35%, Cr0.1% 〜1%, Si1〜10%, Mn, Sb,
1 to 10% of Ti, Ni, Fe, Zr, Mo, Co, and 1 to 10% of the total amount of which is 10% or less, and the balance of Al, and further Cu and / or Mg, if necessary. Is 3.0% or less, or instead of or in addition to this, one or two or more kinds of Pb, Bi, In is added by 9% or less.

Japanese Patent Publication No. 37-15014 discloses a composite metal strip for producing a bearing, which is essentially made of a strip of aluminum or aluminum alloy and aluminum-tin alloy that does not contain tin, or essentially contains tin, through a rolling mill. Roll-bonding the two by reducing the dimensions of the two, the essentially tin-free or essentially tin-free surface of the double-layered strip thus produced and the strip of steel being passed through the rolling mill in the first pass. Of the composite metal strip, which comprises rolling-bonding the steel of said surface into strips by means of a mechanical reduction, each strip being appropriately manufactured prior to the rolling-bonding step on the surface to be joined. The main point is the manufacturing method.

Japanese Patent Publication No. 44-28174 discloses a synthetic material for manufacturing bearings, which is a method for producing an alloy material for manufacturing bearings in which a surface layer of a high tin aluminum alloy is adhered to the surface of a steel backing plate. A method of roll-pressing a tin aluminum alloy strip and these intermediate aluminum foil strips and heating at least one of the high tin aluminum alloy strip and the steel strip to a temperature not exceeding about 230 ° C. To do.

[Problems to be Solved by the Invention] Although each of the known aluminum bearing alloys has excellent performance as compared with the conventional ones, it is required to have a smaller size and a higher output like the internal combustion engines of recent years. If so, the bearing material will be used under conditions of higher load and temperature, and under such adverse conditions, conventional bearing materials will suffer fatigue damage, abnormal wear, seizure, etc. It was a factor.

The aluminum bearing alloy of Japanese Patent Publication No. 58-14866 is
There was a problem in terms of fatigue strength due to insufficient adhesion to the backing steel plate.

Further, Japanese Patent Publication No. 37-15014 and Japanese Patent Publication No. 44-28174
The bearing material of the publication is a three-layer bearing material in which an intermediate layer made of Al or Al alloy is provided between a back metal and a lining layer made of Al bearing alloy. The layer is provided for the purpose of increasing the adhesive strength when the adhesion strength between the backing metal and the lining layer is small, that is, when it is difficult to firmly adhere the lining layer to the backing metal. It was not intended to improve the fatigue strength, and as shown in the experimental results below, the fatigue strength of the conventionally known three-layer bearing material was not so much improved. This is because the high temperature hardness of the lining layer and the high temperature hardness of the intermediate layer used in the conventional three-layer bearing material are about the same, and both the lining layer and the intermediate layer may become soft under high temperature conditions. it is conceivable that.

“Means for Solving Problems” In order to solve these problems, the inventors of the present invention are more effective in improving strength at higher temperatures, seizure resistance, and fatigue strength. We have found various combinations. That is, an Al bearing alloy having a large high temperature hardness, such as the aluminum bearing alloy of Japanese Patent Publication No. 58-14866, is used as a lining layer, and a substantial amount of a high temperature hardness smaller than that of the lining layer between the back metal and the lining layer. This is done by paying attention to the fact that the fatigue strength is further improved by providing an intermediate layer made of pure Al or an Al alloy.

The bearing material of the present invention comprises a backing metal and at least 3 to 35 wt%.
Of Sn and 0.1-10 wt% of Zr, V, Nb, Mo, and Co, and a lining layer made of an Al bearing alloy having a high high temperature hardness, and interposed between the back metal and the lining layer. An intermediate layer made of Al or Al alloy having a high temperature hardness smaller than that of the lining layer is provided, and the thickness of the intermediate layer is basically thinner than that of the lining layer, and if necessary, Si, Mn in the lining layer. , Sb, Ti, Ni, Fe, at least one or more, or instead of, or together with, at least one or more of Cu, Mg, or instead or together with Pb, Bi, T1 At least one of Cd, In and Cd can be added. In addition, Si, Cu, Pb, etc. can be added to the intermediate layer depending on the use.

Sn in the aluminum bearing alloy of the present invention is an element added for the main purpose of lubrication. If it is less than 3 wt%, the effect of lubrication is not exerted, and if it exceeds 35 wt%, it becomes soft as a whole and the load resistance is lowered. The preferable addition amount of Sn is 3.5 to 2
At 0%, a more preferable addition amount is 5 to 15%.

Zr, V, Nb, Mo and Co are elements added mainly for the purpose of improving the high temperature hardness, and improvement in the 0.1 wt% high temperature hardness cannot be expected.If added in excess of 10 wt%, precipitates will form. It will precipitate too much and become too hard as a bearing alloy. The preferable range of addition is 0.2 to 3%, and the more preferable range is 0.3 to
1%.

In addition, maintaining high temperature strength by adding Zr, V, Nb, Mo, Co,
The fine effect of the texture will be described later.

The addition amount of Cu and Mg is 0.2% to 2%, which is added in order to further reduce the decrease in strength at high temperature.
If it is less than 0.2%, the effect cannot be expected so much, and if it is added in excess of 2%, it becomes too hard and hinders the rolling property, and the corrosion resistance decreases. A more preferable range is 0.2 to 1.5%,
The most preferred range is 0.5 to 1.2%.

When added to the Al alloy of the intermediate layer, Cu and Mg can be added for the same purpose as described above.

Si, Mn, Sb, Ti, Ni and Fe are added for the purpose of improving wear resistance, and the total amount of at least one of Zr, V, Nb, Mo and Co is 10 wt% or less. . If it is less than 0.2%, the amount of precipitation is small and effective improvement of wear resistance is not observed.
This is because if it is added in excess of 10%, precipitates will be excessively deposited, the rolling property will deteriorate, and it will be difficult to repeat rolling and annealing, and the refinement of Sn will be hindered. A more preferable range is 0.
5 to 5%, and the most preferable range is 1.5 to 3%.

Furthermore, the present invention uses one or two of Pb, Bi, Tl, Cd and In to improve the performance of Sn as a lubricating metal, if necessary.
The total amount of the seeds is 9 wt% or less. If it is less than 0.1%, the effect of improving the lubricity cannot be expected. On the contrary, if it exceeds 9%, it becomes too soft and the fatigue resistance deteriorates. A more preferable range is 0.5 to 5%, and a most preferable range is 1 to 3%.

"Operation" When the thickness of the intermediate layer is made thinner than the thickness of the lining layer by interposing the intermediate layer having the low temperature hardness between the back metal and the lining layer having the high temperature hardness, the lining layer is While the hardness does not decrease so much, the hardness of the intermediate layer decreases greatly and the intermediate layer with low high temperature hardness acts as a cushioning material for the lining layer with high temperature hardness, which results in fatigue strength. Is expected to improve. Further, especially when the intermediate layer is made of pure Al or an Al alloy close to this, the heat dissipation of the lining layer is improved, which is also considered to be useful for improving fatigue strength.

 Next, the action of each additive element will be described.

Zr, V, Nb, Mo, and Co raise the Al recrystallization temperature by forming a solid solution in Al, and the solid solution itself raises the hardness of the Al base. Also increases the hardness compared to during casting. Increasing the recrystallization temperature is effective in maintaining stable mechanical properties even in the high temperature region where the bearings of the internal combustion engine are exposed, and especially with regard to hardness, decrease in hardness at high temperature is reduced. It brings about the improvement of bearing strength in the high temperature region. Further, the intermetallic compounds of Al-Zr, Al-V, Al-Nb, Al-Mo, and Al-Co which precipitate beyond the solid solution limit are stable even at high temperatures, and therefore these precipitates are finely dispersed. This raises the recrystallization temperature and helps maintain the high temperature hardness, so that a proper amount of this dispersion has a good effect.

Furthermore, if the precipitate is present in a finely dispersed state in the Al base metal, the intermetallic compound directly moves Al grain boundaries,
That is, coarsening of the Sn particles is prevented, which leads to keeping the Sn particles that have been made fine by repeating rolling and annealing, and has the various effects described above. Also
The fact that sn particles are preserved in a fine state and exist in Al ingot is also effective in preventing elution phenomenon of Sn particles having a low melting point of 232 ° C at high temperature.

There is some such effect in Cr, but in the case of Cr it is 450
While coarsening of Sn begins at 30 ℃ for 30 minutes, Zr, V, Nb, Mo, Co
In the case of, it has the ability to prevent the coarsening of Sn even at 500 ° C for 30 minutes.

Further, the effect of Cu strength occurs when Zr, V, Nb, Mo, and Co are added at the same time, and Cu alone cannot be expected to have the effect of increasing strength at high temperatures. That is, Cu has a large increase in hardness during rolling when added to Al, and the increase in hardness is remarkable compared to Al materials added with other elements even at the same rolling rate, but up to near 200 ° C. When heated, it softens easily and cannot maintain high-temperature strength. On the other hand, when at least one of Zr, V, Nb, Mo, Co and Cu are added at the same time, even if the hardness increased during rolling due to the addition of Cu is annealed, Zr, V, Nb, Mo, Co The effect does not decrease much. Therefore, an aluminum bearing alloy having high strength can be obtained, and this strength does not drop significantly even at high temperatures unlike the conventional alloys of this type.

Furthermore, the effect of Pb on lubricity is one of Zr, V, Nb, Mo, and Co.
It is even more effective if added at the same time as the seeds or more. That is, if Pb alone is added to the Al-Sn bearing alloy, Al-
There is an unavoidable drawback that the melting point of Sn becomes low due to alloying into the Sn-based alloy. On the other hand, Zr, V, Nb, Mo, C
If Sn grains are refined by adding o and the structure can be maintained even at high temperature, lubricity can be improved without causing the above-mentioned adverse effects even if Pb is added, Fatigue resistance can be improved.

Si itself has a high hardness and is excellent in castability, and since its precipitate reaches a Vickers hardness of approximately 1000 and is extremely hard, it significantly reduces the wear of the bearing due to sliding with the shaft. be able to. The bearing surface of the bearing is cut softer than the shaft.As this situation progresses, the surface roughness of the bearing becomes rough, or the clearance between the shaft and the bearing increases, and the oil film is no longer formed. Direct contact with the bearing, that is, a large amount of metal contact will cause seizure, but since the above precipitates are harder than the cast iron shaft as well as the hardened steel shaft, the wear resistance when using the cast iron shaft It is particularly effective in improving the seizure resistance and seizure resistance.

[Examples] The present invention will be described below with reference to the illustrated examples. In FIG. 1, 1 is a backing plate made of a steel plate, 2 is an intermediate layer made of Al or Al alloy having a low high temperature hardness, and 3 is a high temperature hardness.
A lining layer made of an Al bearing alloy, the back metal 1, the intermediate layer 2 and the lining layer 3 are pressed together to form a bearing material 4. As is clear from FIG. 1, the thickness of the intermediate layer 2 is set thinner than that of the lining layer 3.

The intermediate layer 2 having a low high temperature hardness is substantially pure Al,
For example, it may consist of commercially pure Al, or it may be added with a total amount of 0.1 to 2% Cu, Mg, or both. In the embodiment, the thickness of the intermediate layer 2 is a fraction of the thickness of the lining layer 3 as shown in FIG.

Next, the effects of the present invention will be described with reference to experimental results. This experiment was carried out by using a rotary load tester to measure how much the fatigue resistance of a sample provided with the intermediate layer 2 and a sample not provided with the intermediate layer 2 (both produced as sliding bearings) were improved.
The shaft is rotated at 8000 rpm and the surface pressure of the sample to be measured is 300 kg / c.
This is a measurement of the time required for fatigue to occur in the sample when a rotational load of m ² is applied. At this time, the oil temperature was 160 ° C and the lubricating oil was 7.5w-30.

Table 1 below shows the composition of the lining layer 3 made of the Al bearing alloy having a high high temperature hardness in the samples used in the above experiments, and the experimental results for each sample. Is used as the intermediate layer 2 having a small thickness of 50 .mu.m.

In Table 1, Samples 1 to 24 are products of the present invention, Samples 25 to 28
Is a comparative material. Also, in the fatigue time column, 20 or more or
The description of 30 or more means that fatigue did not occur even after 20 hours or 30 hours.

Thus, as can be understood from the experimental results in Table 1, the samples according to the present invention are remarkably improved in fatigue strength, and the fatigue strength in Samples 3, 10, 12, 18, and 20 is set in the intermediate layer 2. As a result, it is improved by 300% or more, and all the samples of the present invention show an improvement of 200% or more.

On the other hand, in the comparative materials 25 to 28 having the lining layer 3 which does not contain one or more of Zr, V, Nb, Mo and Co, and therefore has a low high temperature hardness, the maximum amount of the sample 28 is 171.
It is recognized that the improvement of fatigue strength cannot be expected so much even when the intermediate layer 2 is provided as compared with the sample of the present invention.

[Advantages of the Invention] As described above, according to the present invention, the fatigue resistance can be significantly improved by providing the lining layer having a high high temperature hardness with the intermediate layer having a lower high temperature hardness. Has an unexpected effect.

[Brief description of drawings]

 FIG. 1 is a sectional view showing an embodiment of the present invention. 1 ... Back metal, 2 ... Intermediate layer 3 ... Lining layer, 4 ... Bearing material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-55-11182 (JP, A) JP-A-58-6955 (JP, A) JP-B 37-15014 (JP, B1) JP-B 52- 30656 (JP, B2) JP 58-14866 (JP, B2)

Claims (5)

[Claims] 1. A back metal and at least 3-35 wt% Sn and
A lining layer made of an Al bearing alloy having a high temperature hardness and containing 0.1 to 10 wt% of at least one of Zr, V, Nb, Mo and Co, and the lining layer interposed between the back metal and the lining layer. A bearing material comprising an intermediate layer made of Al or an Al alloy having a lower high temperature hardness than that of the lining layer and having a thickness smaller than that of the lining layer. 2. The Al bearing alloy of the lining layer is Si, Mn, S
Patents characterized by containing at least one or more of b, Ti, Ni and Fe, and the total amount of this additive and at least one or more of the above Zr, V, Nb, Mo and Co is 10 wt% or less. The bearing material according to claim 1. 3. The total amount of Al bearing alloy in the lining layer is 0.1.
The bearing material according to any one of claims 1 and 2, characterized in that the bearing material contains one or both of Cu and Mg in an amount of ˜2 wt%. 4. The total amount of Al bearing alloy in the lining layer is 9%.
The bearing material according to any one of claims 1 to 3, which contains one or more of the following Pb, Bi, T1, Cd, and In. 5. The total amount of Al alloy in the intermediate layer is 0.1 to 2% of C.
The bearing material according to any one of claims 1 to 4, which contains one or both of u and Mg.