JPH09217747A - Aluminum group-bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the load withstanding property by forming the bearing metal of an aluminum - tin group alloy, forming an adhesive layer between the bearing metal and a back plate by pure aluminum, and specifying the thickness of the layer to secure the joining strength of the adhesive layer. SOLUTION: An aluminum - tin group bearing metal 1 (tin content exceeds 6wt.%) is stuck on the surface of a steel back plate 3 through an adhesive layer 2, the whole is rounded-formed into a semi-cylindrical shape, and the surface of the bearing metal 1 is adapted to serve as a sliding-friction surface 1a. Further, the adhesive layer 2 is formed of pure aluminum, and the thickness of the adhesive layer 2 is set to 20μm or less. Even when the thickness of the layer is thinner, the load withstanding property can be ensured without causing the loss of the adhesive strength, because of the feature in plastic deformation of the pure aluminum. Thus, the ensurance of the joining strength by the pure aluminum can be compatible with the reduction in the amount of deformation of the adhesive layer, the load withstanding property of the bearing is enhanced, and the engine can be rotated at high speeds and at high power levels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum-based bearing which is a sliding bearing used in automobiles, industrial vehicles and the like, and more particularly to an aluminum-tin based backing bearing having excellent load resistance.

[0002]

2. Description of the Related Art In a conventional aluminum-based bearing with a back metal, which uses a conventional aluminum-tin alloy as a bearing alloy, when the bearing alloy and the back metal are adhered to each other, when the bearing alloy has a low tin content, it is directly The bearing alloy is adhered to the back metal, and when the content of tin is high (for example, the tin content exceeds 6% by weight), a nickel plating layer is interposed or a pure aluminum layer is bonded as an adhesive layer.

Further, in recent years, as seen in JP-A-5-302626 and JP-A-6-136475, in order to strengthen and improve the adhesive layer, the adhesive layer is constituted by an aluminum alloy instead of pure aluminum. Improvement measures are also proposed.

However, in any of the conventional joining structures of aluminum-based bearings, sufficient joining strength and load bearing capacity of the bearing cannot be achieved at the same time. That is, when a bearing alloy made of an aluminum-tin alloy is directly bonded to the back metal, tin having a poor bonding strength is present at the interface with the steel, and the bonding strength is weakened.
Also, when a similar aluminum-tin alloy is joined to the back metal via nickel plating, tin is present at the interface between the nickel plating and the bearing alloy, and there is a technical problem that sufficient joining force cannot be obtained. doing. This decrease in the bonding strength due to tin becomes more significant as the proportion of contained tin increases.

On the other hand, when the adhesive layer is reinforced with an aluminum alloy to have an increased hardness, when a relative slip occurs between the adhesive layer and the back metal during joining with the back metal, the strengthened adhesive layer However, since it does not stretch as much as pure aluminum, it has a technical problem that adhesion to the back metal is less likely to occur and, as a result, sufficient bonding strength cannot be ensured. Therefore, it is considered that the joint strength is increased by re-pressing, but in that case, the hardness of the back metal increases, and then it becomes difficult to process the bearing into a semi-cylindrical bearing shape.

Further, in the conventional example in which the adhesive layer between the bearing alloy and the back metal is made of pure aluminum, the thickness of the adhesive layer is set to about 30 μm or more. Therefore, due to the action of repeated load on the bearing, the adhesive layer together with the bearing alloy undergoes plastic deformation protruding toward the end face in the bearing width direction of the backing metal, which may cause the bearing to be broken.
In addition, a crack is generated in the bearing alloy due to the impact load acting on the sliding friction surface, and the crack propagates to the adhesive layer, resulting in deterioration of load resistance.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional technical problems, and has the following configuration. According to the invention of claim 1, in an aluminum-based bearing in which a bearing alloy 1 is fixed to a steel backing metal 3 via an adhesive layer 2, the bearing alloy 1 is an aluminum-tin alloy, and the bearing alloy 1 is between the backing metal 3 and the backing metal 3. Of the adhesive layer 2 of pure aluminum, and the thickness of the adhesive layer 2 is 20 μm.
The aluminum-based bearing is characterized by being set to m or less. According to a second aspect of the present invention, in an aluminum-based bearing in which the bearing alloy 1 is fixed to the steel backing metal 3 via the adhesive layer 2, the bearing alloy 1 is an aluminum-tin alloy, and the bearing alloy 1 and the backing metal 3 are provided. The adhesive layer 2 is made of pure aluminum, and the thickness of the adhesive layer 2 exceeds 5 μm.
The aluminum-based bearing is characterized by being set in a range of μm or less.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show one embodiment of an aluminum-based bearing according to the present invention. As shown in FIG. 1, the aluminum-based bearing has an aluminum-tin based bearing alloy 1 on one side of a steel backing 3 with an adhesive layer 2 interposed therebetween.
Formed by sticking (tin content exceeding 6% by weight),
This is a plain bearing that is entirely formed into a semi-cylindrical shape. The surface (the upper surface in FIG. 1) of this bearing alloy 1 is a sliding friction surface 1a.
To form In such a bearing with an aluminum-tin based back metal, the adhesive layer 2 between the bearing alloy 1 and the back metal 3 is formed of pure aluminum, and the thickness of the adhesive layer 2 is set to 20 μm or less. Here, pure aluminum refers to aluminum in the 1000 range defined by JIS.
Percentage or more.

The reason why the thickness of the adhesive layer 2 made of pure aluminum is set to 20 μm or less will be described. As described above, the adhesive layer 2 is reinforced as an aluminum alloy,
When an intermediate layer having an increased hardness is used, when a relative slip between the reinforced adhesive layer 2 and the back metal 3 occurs during bonding with the back metal 3, sufficient bonding strength cannot be ensured. When the relative slip between the adhesive layer 2 and the back metal 3 is subjected to re-reduction to increase the bonding strength, the hardness of the back metal 3 increases, so it is preferable to round the sliding bearing shape. It will be difficult. Therefore, as the material of the adhesive layer 2,
Pure aluminum was selected because of its good bonding strength.

However, in the conventional bearing with an aluminum-tin based backing having the adhesive layer 2 formed of pure aluminum, the thickness of the adhesive layer 2 is set to about 30 μm or more. For this reason, for example, in a bearing structure in which a high load is applied with the recent increase in engine speed and output, the bonding layer 2 made of pure aluminum is soft and easily deformed. Although the strength can be obtained, it has been found that the adhesive layer 2 shown in FIG. 5 is deformed, which causes a problem in the load resistance of the bearing.

That is, by the action of the repeated load W from the sliding friction surface 1a, the adhesive layer 2 is gradually deformed together with the bearing alloy 1 so as to protrude from the end face in the bearing width direction of the backing metal 3. FIG. 5 shows a protrusion amount (deformation amount Δ) of the bearing alloy 1 with respect to the backing metal 3 in the bearing width direction (center axis direction) in the conventional aluminum-based bearing. Due to this deformation amount Δ, the bearing may be destroyed, and the sliding friction surface 1
Due to the impact load acting on a, a crack 4 is generated in the aluminum-tin bearing alloy 1, and the crack 4 propagates and grows on the thick adhesive layer 2 made of pure aluminum by the action of the repeated load W thereafter. As a result, the load resistance is reduced.

The inventors of the present invention have paid attention to the good bonding strength of the adhesive layer 2 made of pure aluminum, and for the purpose of improving the load resistance when the adhesive layer 2 made of pure aluminum is used, the pure aluminum is used. The characteristics of plastic deformation of Then, the adhesive layer 2 made of pure aluminum having various thicknesses
It has been found that the bearing having the above-mentioned structure can be made to have a load bearing ability without impairing the adhesive strength by making the thickness of the layer extremely thin by exploring the characteristics of the plastic deformation of pure aluminum.

Specifically, the adhesive layer 2 made of pure aluminum
Is repeatedly applied to an aluminum-tin-based bearing with a back metal having a thickness of about 50 μm, the amount of deformation Δ occurring at the end face portion of the adhesive layer 2 in the bearing width direction and the distance from the back metal surface 3a (radial direction). Distance). The result is shown in FIG. What is characteristic of this modification is that the adhesive layer 2 immediately above the back metal 3, which is in the vicinity of the back metal surface 3a, is constrained by the back metal 3 and the strength of pure aluminum is small.
The amount of plastic deformation is small. However, the amount of deformation cumulatively increased from the portion where the distance from the back metal surface 3a exceeded 20 μm.

When the hardness of the adhesive layer 2 made of pure aluminum having a thickness of about 50 μm was measured by using a micro hardness (Knoop hardness) meter, the results shown in FIG. 4 were obtained.
From the result of the Knoop hardness of the adhesive layer 2, the adhesive layer 2 up to a thickness of about 20 μm directly above the backing metal 3 is less likely to be plastically deformed due to the influence of the backing metal 3, and it is similar to the case where the adhesive layer 2 is reinforced in a phenomenon. It turned out to be effective. That is, it was found that the plastic deformation amount can be suppressed to a very small value by setting the thickness of the adhesive layer 2 made of pure aluminum to 20 μm or less, preferably 15 μm or less.

In FIG. 2, the state of the end face portion in the bearing width direction of the aluminum-tin based backing bearing after the test was carried out under the condition that the thickness of the adhesive layer 2 made of pure aluminum was 15 μm and the load W was repeatedly applied. Indicates. The repetitive load W is generated by fixing the bearing to the large end of the connecting rod and applying a fluctuating load to the shaft (crankshaft) in order to make the load almost the same as the actual engine condition.

The test conditions are as follows. Load surface pressure: 700 kg / cm ² Number of times of load: 1 million times Number of rotations of shaft: 3500 rpm Shaft material: FCD70, roughness: 0.8 to 1.5S Lubricating oil: 10W-30 Oil temperature: 150 ± 5 ° C Aluminum-tin bearing alloy used in the test 1
The composition of Al-13% Sn-2% Pb-3% Si-
0.7% Cu-others (less than 1%).

[0017]

EXAMPLE A bearing alloy 1 having the above composition and a backing metal 3 were pressure-welded to each other so that the adhesive layer 2 made of pure aluminum had various thicknesses, and 10 aluminum-based bearings each were manufactured. The test was performed under the above conditions by repeatedly applying a load W. As a result, the proportion of bearings that did not break is shown in Table 1 as the proportion of healthy bearings.

[0018]

As can be seen from Table 1, when the thickness of the adhesive layer 2 made of pure aluminum is 20 μm or less, the deformation amount Δ of the adhesive layer 2 shown in FIG. 2 is small and the ratio of sound bearings is 9%.
It is as high as 0 to 100%, and most of them maintain a healthy state. The function of the adhesive layer 2, that is, the backing plate 3 made of steel and the bearing alloy 1 made of an aluminum-tin alloy as an intermediate layer
In order to completely secure the function of joining and, it is desirable that the thickness of the adhesive layer 2 exceeds 5 μm.

On the other hand, it can be seen that the thick adhesive layer 2 made of pure aluminum according to the conventional example has a remarkably large amount of deformation Δ and the ratio of sound bearings is as low as 30 to 40%. That is, when the adhesive layer 2 made of pure aluminum according to the conventional example has a thickness of 30 μm or more, the deformation amount Δ is large.
The proportion of unhealthy bearings that have been damaged by the occurrence of the crack 4 shown in (3) is extremely high. In addition, the improvement rate of the ratio of the healthy bearing to the above-mentioned conventional example is 225 to 250% according to the present examples.

[0021]

As will be understood from the above description,
According to the present invention, in the aluminum-based bearing, the thickness of the adhesive layer made of pure aluminum between the aluminum-tin bearing alloy and the steel back metal is set to 20 μm or less, so that the pure aluminum is sufficient. It is possible to satisfactorily achieve both the securing of the bonding strength and the reduction of the deformation amount of the adhesive layer. As a result, the load bearing capacity of the aluminum-based bearing can be remarkably increased, and in particular, it has been possible to contribute to high engine rotation and high output.

[Brief description of drawings]

FIG. 1 is a sectional view showing an essential part of an aluminum-based bearing according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of the same operation.

FIG. 3 is a diagram showing a characteristic from a distance from a back metal surface to a deformation amount of an adhesive layer.

FIG. 4 is a diagram showing the distance from the back metal surface-Knoop hardness characteristics of the adhesive layer.

FIG. 5 is a sectional view showing a main part of an aluminum-based bearing according to a conventional example.

[Explanation of symbols]

 1: bearing alloy, 2: adhesive layer, 3: back metal, Δ: amount of deformation.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Sakai 1-687 Mitomicho, Narashino, Chiba Prefecture NDC Corporation

Claims (2)

[Claims] 1. An aluminum-based bearing in which a bearing alloy (1) is fixed to a steel backing (3) via an adhesive layer (2), wherein the bearing alloy (1) is an aluminum-tin alloy, and the bearing alloy ( An aluminum-based bearing characterized in that the adhesive layer (2) between 1) and the back metal (3) is formed of pure aluminum, and the thickness of the adhesive layer (2) is set to 20 μm or less. 2. An aluminum-based bearing in which a bearing alloy (1) is fixed to a steel backing (3) via an adhesive layer (2), wherein the bearing alloy (1) is an aluminum-tin alloy and the bearing alloy ( The adhesive layer (2) between 1) and the backing metal (3) is formed of pure aluminum, and the thickness of the adhesive layer (2) is set in the range of more than 5 μm and 15 μm or less. Aluminum-based bearing.