KR20120136402A - Aluminum alloy bearing - Google Patents

Abstract

The aluminum alloy bearing contains 1.0 to 10.0% by weight of Si and the Si particles are dispersed. The aluminum alloy bearing is characterized in that the diffraction intensity ratio of the (111) plane of the Si particles is 0.6 or more.

Description

Aluminum Alloy Bearing {ALUMINUM ALLOY BEARING}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy bearing having good abrasion resistance and excellent aluminum resistance bearings as an engine bearing for an internal combustion engine.

Background Art Conventionally, engine bearings for internal combustion engines require abrasion resistance and sinter resistance, and aluminum alloy bearings having an intermediate layer provided between a back metal layer and an aluminum bearing alloy layer have been used to satisfy these requirements. As this aluminum bearing alloy layer, for example, Japanese Patent Laid-Open No. 2003-119530 (Patent Document 1) contains small Si particles and large Si particles in an appropriate ratio in an Al matrix to improve fatigue resistance and improve wear resistance. Si particle-containing aluminum alloy bearings (Al-Sn-Si bearing alloys) have been proposed.

Japanese Patent Laid-Open No. 2003-119530

By the way, the technique disclosed by patent document 1 was to pay attention to the size of Si particle, and to improve fatigue resistance and abrasion resistance. However, in today's strict use environment, bearings often deform due to misalignment during assembly and lack of rigidity of the housing due to light weight and compactness. In such a case, the frequency of contact with the shaft increases and heat is generated, thereby reducing the strength of the bearing material, causing cracks, and breaking of the oil film.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide an aluminum alloy bearing having good sinter resistance by avoiding breakage of the oil film by preventing crack generation due to a decrease in material strength.

In order to achieve the above object, the invention according to claim 1 comprises 1.0 to 10.0% by weight of Si, and the diffraction intensity ratio of the (111) plane of the Si particles in an aluminum alloy bearing in which Si particles are dispersed. ) Is 0.6 or more.

According to the second aspect of the present invention, in the aluminum alloy bearing according to claim 1, the aluminum alloy bearing has a bearing inside at a position deeper than the bearing surface in the bearing surface and the thickness direction, 111) The ratio (Dr) of the diffraction intensity of the plane and the diffraction intensity of the (111) plane of the Si particles in the bearing is 0.8 ≦ Dr ≦ 1.2.

The invention according to claim 3 contains at least one of the following items (a) to (c) in the aluminum alloy bearing according to claim 1 or 2.

(A) 0.1 to 7.0% by weight in total of one or more selected from Cu, Zn, and Mg.

(B) 0.01 to 3.0% by weight in total of one or more selected from Mn, V, Mo, Cr, Co, Fe, Ni, and W.

(C) 0.01 to 2.0% by weight of one or more selected from B, Ti, and Zr as a total amount.

In the invention according to claim 1, good diffraction resistance can be obtained when the diffraction intensity ratio of the (111) plane of the Si particles whose crystal orientation is represented by the Miller index is 0.6 or more. It is thought that this prevents cracking due to lowering of the material strength by reducing the coefficient of friction and reducing the frictional heat in order to prevent seizure while securing wear resistance. In other words, when the diffraction intensity ratio of the (111) plane of the Si particles is high, the friction coefficient is reduced, and the heat generation due to the friction caused by the contact between the Si particles and the shaft is reduced. This is because it is possible to improve sex.

Here, the diffraction intensity ratio of the (111) plane of the Si particles is

Peak intensity of X-ray diffraction of (111) plane = P1

Peak intensity of X-ray diffraction of (220) plane = P2

Peak intensity of X-ray diffraction of (311) plane = P3

When the peak intensity of the (331) plane X-ray diffraction is set to P4,

The diffraction intensity ratio of the (111) plane is represented by P1 / (P1 + P2 + P3 + P4). Other peak intensities ((400) plane, (511) plane, (440) plane, etc.) are not included because they have a low peak intensity, overlap with the background, and have a large error.

By the way, when rolling is carried out to the aluminum alloy which Si particle disperse | distributes, a stress is applied to Si particle disperse | distributing in an Al matrix. The present inventors paid attention to this and found the manufacturing method mentioned later. As a method in which the diffraction intensity ratio of the (111) plane of the Si particles is 0.6 or more, for example, by performing continuous rolling method, the grain size of the Al matrix of the initial billet is set to 30 to 50 µm, and rolling is carried out to eliminate the grains. It was found that it can be realized. And if it is not necessarily limited to a continuous casting method and a method which can manufacture the thing of 30-50 micrometers of crystal grain sizes, you may employ | adopt another well-known method. Dissipation of grains means that grain boundaries become so dense that grain boundaries cannot be identified on the cross-sectional etching structure.

Si particles, on the other hand, have cleaved surfaces on the (111) plane. Therefore, it can be considered that the above-mentioned rolling increases the (111) plane of Si efficiently when stress is added to the Si particles. In addition, the rigidity of the Si particles themselves is very hard, such as 1000 HV, and the roughness of the cleaved surface is sufficiently smoother than the surface roughness of the finished product thereafter, so that the coefficient of friction is lowered, and thus the frictional heat is reduced, resulting in a decrease in material strength. It is possible to prevent the occurrence of cracks, thereby avoiding oil film breakage.

And if the diffraction intensity ratio of the (111) plane of Si particle is less than 0.6, the effect of the lapping effect and the improvement of abrasion resistance of the shaft which the aluminum bearing alloy containing Si particle disclosed in the above-mentioned patent document 1 has can be acquired, but the effect of reducing frictional heat Is very low.

In addition, about invention which concerns on Claim 2, the ratio (Dr) of the diffraction intensity of the (111) plane of Si particle on the bearing surface, and the diffraction intensity of the (111) plane of Si particle inside a bearing is 0.8 <= Dr It is specified as ≤ 1.2.

Aluminum alloy bearings are repeatedly deformed by continuous use. And, if the difference in internal stress between the bearing surface and the inside of the bearing is large, a large relative internal stress occurs between them and the torsional energy is concentrated. If the torsional energy due to deformation is added to it and exceeds the limit that the aluminum alloy bearing can withstand, it causes a crack in the aluminum alloy bearing. On the other hand, by rolling the aluminum alloy bearing in a state in which the change amount of the length in the direction perpendicular to the thickness direction is as small as possible, the difference in the internal stress between the bearing surface and the inside of the bearing is reduced.

That is, the aluminum alloy bearing is rolled in a state where the difference in the amount of change between the bearing surface and the inside of the bearing is small, so that the occurrence of cracks is avoided, and the durability against burning (stretching) is improved. In terms of bearing performance, it is preferable to reduce the difference in the amount of change between the bearing surface and the inside of the bearing, particularly at the surface side that slides from the center in the thickness direction to the mating member. The position inside the bearing can be set at approximately the center position in the thickness direction of the aluminum alloy bearing. When the difference in the amount of change is rolled in a small state, the ratio (Dr) of the diffraction intensity of the (111) plane of the Si particles on the bearing surface and the diffraction intensity of the (111) plane of the Si particles inside the bearing is equal to one. It will be close. At this time, when the ratio Dr of the diffraction intensity is 0.8 ≦ Dr ≦ 1.2, the difference in the amount of change is rolled in a small state, and the difference in the internal stress in the bearing surface and the inside of the bearing becomes small. Therefore, by defining the ratio (Dr) of the diffraction intensity, durability against burning, that is, baking resistance can be increased.

Aluminum alloy bearings may be formed by laminating steel back metals and, in some cases, other members in order to exhibit high bearing performance. The manufacturing method described later is particularly effective when the aluminum alloy bearing is made of such a composite material.

In order to control the ratio Dr of the diffraction intensity, for example, a migration speed roll having a different speed between the upper roll and the lower roll of the rolling roll can be used. Moreover, you may roll by controlling a friction coefficient by adjusting the roughness of the surface of a member which consists of aluminum alloy bearings, or a roll. In this way, the internal stress applied to the aluminum alloy bearing can be controlled by controlling the amount of change by using the migration speed roll or adjusting the surface roughness. Therefore, not only can a stress be added to Si particle suitably by such rolling, but the difference of the internal stress between the bearing surface of an aluminum alloy bearing and the inside of a bearing can be made small.

In addition, as in the invention described in claim 3, various metal elements can be included to improve the strength and heat resistance of the Al matrix.

1 is a schematic diagram showing conditions at the time of wear,
2 is a schematic diagram showing conditions of baking;
3 is a view showing test results of Examples and Comparative Examples.

The aluminum alloy bearing 1 which concerns on this embodiment was produced in the order demonstrated below. First, the grain size of the Al matrix of the initial billet was manufactured to 30-50 micrometers by the continuous casting machine. Then, rolling was repeated until it became predetermined thickness, and the crystal grain was dismissed one or more times in the rolling process which makes this elongation ratio 2 to 8 times, and obtained the aluminum bearing alloy plate. In the rolling process, the upper roll and the lower roll of the rolling roll are rolled at different speeds, for example, by increasing the lower roll by 2% of the upper roll, and / or by roughening the material surface to increase the friction coefficient. Accordingly, the internal stress was given to the aluminum bearing alloy plate while the difference in internal stress between the vicinity of the surface and the predetermined position in the interior was reduced. As a result, more internal distortion can be given to the aluminum bearing alloy plate, and crystal grains can be more efficiently disappeared. In addition, you may perform the annealing process of the torsion removal for split suppression in the middle of a rolling process.

As described above, the aluminum bearing alloy sheet rolled to a predetermined thickness is pressed against the steel back metal to produce a bimetal. At this time, the aluminum plate serving as the adhesive layer may be sandwiched between the aluminum bearing alloy plate and the steel back metal to be pressed. After annealing, annealing may be performed to increase the adhesive force and to remove the torsion, and may be subjected to heat treatment such as solution treatment to reinforce the aluminum bearing alloy plate as necessary. Moreover, you may roll on bimetal. The bimetal manufactured as described above was processed into a semi-cylindrical shape to obtain a half bearing.

The peak intensity of the Si particles was measured by X-ray diffraction using the manufactured half bearing. And the abrasion test was done on the test conditions shown in FIG. 1 of the half bearing measured in this way, and the baking test was done on the test conditions shown in FIG. The abrasion test is to perform a start stop and actively perform contact with the shaft to measure the amount of wear (µm) and to evaluate the wear resistance. In addition, the baking test applies a load to the bearing inner surface and evaluates the maximum surface pressure MPa not baked at a predetermined test time as the baking resistance.

However, the applicant performed the above abrasion test and quenching test, and it was confirmed that the half-bearing having a diffraction intensity ratio of the (111) plane of the Si particles having satisfactory wear resistance and seizure resistance in the half bearing of 0.6 or more. It was confirmed that the half bearing satisfying the ratio (Dr) also had satisfactory wear resistance and seizure resistance, and also had satisfactory wear resistance and seizure resistance in the half bearing including the metal element of claim 3. It could be confirmed.

On the other hand, in the half-bearing whose diffraction intensity ratio of the (111) plane of Si particle | grains is less than 0.6, although it may be satisfied with abrasion resistance, it was confirmed that baking resistance is inferior.

The result of a specific evaluation is demonstrated based on FIG.

Examples 1-7 were produced and prepared as mentioned above. Comparative Example 1 was prepared in the same manner using a conventional rolling process that does not dissipate crystal grains.

First, Example 7 and Comparative Example 1 were compared to examine the effect of the diffraction intensity ratio on the (111) plane of the Si particles on the wear resistance and the seizure resistance. In Example 7, the diffraction intensity ratio of the (111) plane of the Si particles was 0.62. This Example 7 had a wear amount of 14 µm, and the maximum surface pressure not baked was 90 MPa. In contrast, Comparative Example 1 has a diffraction intensity ratio of 0.53 on the (111) plane of Si particles. In the case of the standard sample, the diffraction intensity ratio of the (111) plane of the Si particles was 0.51, which is close to Comparative Example 1. In Comparative Example 1, the wear amount was 18 µm and the maximum surface pressure not baked was 70 MPa. From the comparison between Example 7 and Comparative Example 1, it can be seen that both the wear resistance and the baking resistance are improved when the diffraction intensity ratio of the (111) plane of the Si particles is 0.6 or more in consideration of the error. As described above, it was confirmed that the Examples 1 to 7 in which the diffraction intensity ratio of the (111) plane of the Si particles were 0.6 or more improved in the wear resistance and the baking resistance as compared with the Comparative Example 1.

When the diffraction intensity ratio of the (111) plane of the Si particles is 0.7 or more, it was also confirmed that it is particularly preferable for wear resistance.

Next, Example 6 is compared with Example 7 in order to examine the effect of the ratio (Dr) of diffraction intensity on baking resistance. In Example 6, the ratio (Dr) of the diffraction intensity of the (111) plane of Si particles on the bearing surface and the diffraction intensity of the (111) plane of Si particles inside the bearing is Dr = 1.19. In Example 6, the maximum surface pressure not baked was 100 MPa. In contrast, in Example 7, the ratio (Dr) of the diffraction intensity was Dr = 1.21. In Example 7, the maximum surface pressure not baked was 90 MPa. From the comparison between Example 6 and Example 7, it can be seen that the baking resistance is improved when the ratio Dr of the diffraction intensity is 1.2 or less.

Here, in the case of FIG. 3, the ratio (Dr) of the diffraction intensity is calculated as Dr = ｛diffraction intensity of the (111) plane of the Si particles on the bearing surface / diffraction intensity of the (111) plane of the Si particles inside the bearing. .

Thus, by specifying the ratio (Dr) of the diffraction intensity as 0.8≤Dr≤1.2, it was confirmed that the baking resistance was improved. In Figure 3 (Dr) can be confirmed that it is more preferable that the 1.00 or more and 1.19 or less.

In addition, by including various metal elements, the strength and heat resistance of the Al matrix can be improved.

Claims (3)

In the aluminum alloy bearing containing 1.0 to 10.0% by weight of Si and the Si particles are dispersed,
The aluminum alloy bearing, characterized in that the diffraction intensity ratio of the (111) plane of the Si particles is 0.6 or more. The bearing of claim 1, wherein the aluminum alloy bearing has a bearing surface and a bearing interior at a position deeper than the bearing surface in the thickness direction,
The ratio (Dr) of the diffraction intensity of the (111) plane of the Si particles on the bearing surface and the diffraction intensity of the (111) plane of the Si particles inside the bearing is
Aluminum alloy bearing, characterized in that 0.8≤Dr≤1.2. The aluminum alloy bearing according to claim 1 or 2, wherein the aluminum alloy bearing contains any one or more of the following (A) to (C).
(A) 0.1 to 7.0% by weight in total of one or more selected from Cu, Zn, and Mg.
(B) 0.01 to 3.0% by weight in total of one or more selected from Mn, V, Mo, Cr, Co, Fe, Ni, and W.
(C) 0.01 to 2.0% by weight of one or more selected from B, Ti, and Zr as a total amount.

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