JPH0526242A - Sliding member - Google Patents

Abstract

PURPOSE:To provide a sliding bearing provided with a surface layer having the excellent peel strength. CONSTITUTION:A composition plane 4a of a barrier layer 4 is made of aggregate of rectangular pyramid shape projections 6 of Ni crystal, of which tops (a) are directed to the composition plane 4a side. Since surface area of the composition plane 4a is thereby enlarged, and the anchor effect by recessed parts between both projections 6 adjacent to each other is obtained, a surface layer 5 is jointed with the composition plane 4a strongly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a sliding member, and more particularly, to a sliding member having a surface layer provided on a lining layer via a metal barrier layer.

[0002]

2. Description of the Related Art Conventionally, as this type of sliding member, for example, C
A sliding bearing is known which is composed of a lining layer made of a u alloy, a barrier layer made of Ni formed on the lining layer, and a surface layer made of a Pb-Sn alloy formed on the barrier layer. There is. The barrier layer is used for avoiding the problem that Sn in the surface layer diffuses and penetrates into the lining layer to embrittle the lining layer.

[0003]

The barrier layer is generally formed by an electroplating method. However, since the crystal shape of the constituent metal, Ni, is indefinite, it is composed of granular crystals. The interface between the barrier layer and the surface layer is flat when viewed microscopically.

On the other hand, the surface layer is also formed by the electroplating method like the barrier layer. However, since the joint surface of the barrier layer is flat and the surface area thereof is small as described above, the surface layer of the barrier layer is different from that of the barrier layer. There is a problem that the peel strength is low.

In view of the above, it is an object of the present invention to provide the sliding member in which the peeling strength of the surface layer from the barrier layer is improved by specifying the structure of the barrier layer.

[0006]

The present invention provides a sliding member having a surface layer provided on a lining layer via a metal barrier layer, wherein the barrier layer is formed by deposition on the lining layer. It is characterized in that it has a plurality of projections of metal crystals so as to form a joint surface with the surface layer.

[0007]

1 and 2, a sliding bearing 1 as a sliding member is applied to a journal portion of a crankshaft in an engine, a large end portion of a connecting rod, and the like.
It consists of first and second halves 1 ₁ and 1 ₂ . Both halves 1 ₁ ,
1 and ₂ have the same structure, and include a back metal 2, a lining layer 3 formed on the inner surface of the back metal 2, a barrier layer 4 formed on the surface of the lining layer 3 by electroplating, and a barrier layer 4.
Mating member x formed on the surface of the plate by electroplating
And a surface layer 5 having a sliding surface 5a. Back metal 2
A Cu plating layer is provided between the lining layer 3 and the lining layer 3 as required.

The back metal 2 is made of a rolled steel plate, and its thickness is determined by the set thickness of the slide bearing 1. The lining layer 3 is made of Cu, a Cu-based alloy, Al, an Al-based alloy, or the like, and has a thickness of 50 to 500 μm, usually 300 μm.
It is about m. The barrier layer 4 is made of a simple substance such as Ni, Fe or Co or an alloy thereof, and has a thickness of 0.1 to 10.
It is 5 μm, usually about 1 to 2 μm. The surface layer 5 is Pb
It is composed of an alloy and its thickness is 5 to 50 μm, usually 2
It is about 0 μm.

As the alloying element in the barrier layer 4,
At least one selected from P, B, Co, Zn, Fe and W can be mentioned, and the content of the alloying element is 1
It is set to 0% by weight or less.

The Pb alloy forming the surface layer 5 is 80-9.
It contains 0% by weight of Pb and 3 to 20% by weight of Sn, and if necessary Cu, In, Ag, Tl, Nb, Sb, N.
10% by weight or less of at least one selected from i, Cd, Te, Bi, Mn, Ca and Ba.

Cu, Ni, and Mn have the function of improving the hardness of the surface layer 5, but if the content thereof exceeds 10% by weight, the hardness becomes too high and the initial conformability deteriorates.
When Cu or the like is added, the hardness Hmv of the surface layer 5 is 1
It is desirable to adjust the content so as to be 5 to 25.

In, Ag, Tl, Nb, Sb, Cd, T
e, Bi, Ca, and Ba have the function of softening the surface layer 5 to improve the initial conformability, but if the content thereof exceeds 10% by weight, the strength of the surface layer 5 decreases. When In or the like is added, it is desirable to adjust the content so that the hardness Hmv of the surface layer 5 becomes 8 to 15.

A plating solution for electroplating for depositing and forming the barrier layer 4 is 50 to 20 per liter.
0 g Ni ²⁺ and optionally 30 g per liter
The sulfuric acid plating solution containing the following ammonium chloride, boric acid, organic additives, etc. is used. The pH of the plating solution is set to 3 to 6, the temperature of the plating solution is set to 10 to 60 ° C., and the cathode current density is set to 12 A / dm ² .

FIG. 3 (a) is an electron micrograph (5,000 times) showing the crystal structure of Ni on the surface of the barrier layer 4, that is, the bonding surface 4a with the surface layer 5, and FIG. 3 (b) is
It is a schematic diagram of the same figure (a). The barrier layer 4 is deposited and formed on the Cu alloy lining layer 3, and the average cathode current density in the electroplating process when forming the barrier layer 4 is 4
It was set to A / dm ² .

Barrier layer 4 as best shown in FIGS.
Has a plurality of fine metal crystals with the apex a directed toward the bonding surface 4a, that is, quadrangular pyramidal projections 6 made of Ni crystal, so as to form the bonding surface 4a. Each quadrangular pyramid-shaped projection 6 forms the tip of each columnar crystal 7 extending from the lining layer 3. The barrier layer 4 has a thickness of 1 to 3 μm, and the area ratio of the quadrangular pyramidal projections 6 on the joint surface 4 a is 100%.

When the joint surface 4a is formed by the fine quadrangular pyramidal protrusions 6 as described above, the surface area of the joint surface 4a is greatly expanded, and a valley portion between the adjacent quadrangular pyramidal protrusions 6 is formed. Since a large anchor effect is obtained, the peel strength of the surface layer 5 can be improved.

FIG. 5 shows the X of the Ni crystal in the barrier layer 4.
FIG. 3 is a line diffraction diagram, and the (200) plane and (4
Only the diffraction peak of the (00) plane is recognized.

Here, the orientation index Oe is used as an index representing the orientation of the crystal plane, (However, hkl is Miller index, Ihkl is (hkl)
If the integral intensity of the surface, ΣIhkl, is defined as the sum of Ihkl), the orientation index Oe of the (hkl) surface is 1
The closer it is to 00%, the more crystal planes are oriented in the direction orthogonal to the (hkl) plane.

The (200) plane and (40) of the Ni crystal are
Table 1 shows the integrated intensity Ihkl and the orientation index Oe in the (0) plane.

[0020]

[Table 1] From Table 1, the orientation index O in the (h00) plane of the Ni crystal is
Since e is 100%, the Ni crystal has a crystal plane oriented in each axial direction on the crystal axes a, b, and c, that is, a (h00) plane. As a result, the joint surface 4
a is a Ni crystal with the (h00) plane facing the bonding surface 4a side,
Therefore, it can be seen that it is formed by the aggregate of the quadrangular pyramidal protrusions 6.

As described above, when the crystal plane is oriented in the direction orthogonal to the (h00) plane, the crystal structure of Ni is a face-centered cubic structure, so the atomic density in the orientation direction becomes high, so the barrier layer The hardness of No. 4 increases and its strength improves.

FIG. 6 is an electron micrograph (10,000 times) showing the crystal structure of Ni on the bonding surface of the conventional barrier layer. The barrier layer is formed on the Cu alloy lining layer by electroplating.

FIG. 7 is an X-ray diffraction diagram of Ni crystal in the conventional barrier layer. Orientation to a specific crystal plane is not recognized from this figure. Table 2 shows the integrated intensity Ihkl and the orientation index Oe in various (hkl) planes.

[0024]

[Table 2] As is clear from FIG. 6, FIG. 7 and Table 2, N of the conventional example
The crystal shape of i is an indefinite shape in which the crystal planes are randomly oriented, and therefore the barrier layer is formed of an aggregate of granular crystals.

The electroplating solution for depositing and forming the surface layer 5 includes 40 to 180 g of Pb ²⁺ per liter, 1.5 to 35 g of Sn ²⁺ per liter, and 1 liter if necessary. A fluorinated plating solution containing 15 g or less of Cu ²⁺ is used. The temperature of the plating solution is set to 10 to 35 ° C. and the cathode current density is set to ³ to 15 A / dm ² .

FIG. 8 is an electron micrograph (× 10,000) showing the crystal structure of the Pb alloy on the sliding surface 5a.
Is an electron micrograph (5,000 times) showing the crystal structure of the Pb alloy when the surface layer 5 is longitudinally cut. The surface layer 5 is made of a Pb alloy containing 8 wt% Sn and 2 wt% Cu. The surface layer 5 was deposited and formed on the barrier layer 4 having the (h00) plane orientation, and the cathode current density in the electroplating treatment when forming the surface layer 5 was set to 6 A / dm ² .

As clearly shown in FIGS. 8 to 10, the surface layer 5
Has a plurality of quadrangular pyramidal protrusions 8 made of Pb alloy crystals, that is, a plurality of metal crystals with the apex b directed toward the sliding surface 5a so as to form the sliding surface 5a. Each quadrangular pyramidal protrusion 8 forms the tip of each columnar crystal 9 extending from the barrier layer 4.

When the sliding surface 5a is formed by a plurality of quadrangular pyramidal protrusions 8 as described above, the vertex b side of the quadrangular pyramidal protrusions 8 is preferentially worn to improve the initial conformability of the surface layer 5. And the sliding surface 5a
It is possible to increase the surface area of the and to give the surface layer 5 sufficient oil retaining property. As a result, the surface layer 5 exhibits excellent seizure resistance.

In the quadrangular pyramidal projection 8, when the preferential wear on the apex b side is completed and a flat surface (corresponding to the upper bottom surface of the quadrangular pyramid base) is formed at the beginning of sliding, the flat surface becomes Since an oil film always exists between the mating member and the mating member, the sliding surface 5a thereafter wears extremely slowly.

FIG. 11 is an X-ray diffraction diagram of the Pb alloy crystal in the surface layer 5, and only the diffraction peaks of the (200) plane and the (400) plane are recognized by the Miller index.

Table 3 shows the integrated intensity Ihkl and the orientation index Oe in the (200) plane and the (400) plane of the Pb alloy crystal.

[0032]

[Table 3] From Table 3, the orientation index Oe in the (h00) plane of the Pb alloy crystal is 100%, and therefore the Pb alloy crystal is
Crystal planes oriented in the respective axis directions of the crystal axes a, b, and c,
That is, it has a (h00) plane. This shows that the sliding surface 5a is formed of a Pb alloy crystal with the (h00) plane facing the sliding surface side, that is, an aggregate of the quadrangular pyramidal projections 8.

(H0 of the Pb alloy crystal in the surface layer 5)
The 0) plane orientation and the adhesion of the surface layer 5 to the barrier layer 4 are promoted by the Ni crystals in the barrier layer 4 having the same orientation.

As described above, when the crystal plane is oriented in the direction orthogonal to the (h00) plane, the crystal structure of the Pb alloy is a face-centered cubic structure, so that the atomic density in the orientation direction becomes high. The hardness of the layer 4 is increased to improve its seizure resistance and wear resistance.

In the barrier layer 4, when the Ni crystal has the (h00) plane orientation as described above, the inclination angle of the quadrangular pyramidal projection 6 is within a predetermined range.

That is, as shown in FIG. 12A, an imaginary plane S along the joint surface 4a is defined on the bottom surface side of the quadrangular pyramidal projection 6, and the apex a and the bottom surface of the quadrangular pyramidal projection 6 are defined. When the inclination angle of the straight line u passing through the central portion t with respect to the reference line v passing through the central portion t of the bottom surface and perpendicular to the virtual surface S is defined as θ, the inclination angle θ of the quadrangular pyramidal projection 6 is 0 ° ≦. θ ≦ 30 °.

In the present invention, not only the quadrangular pyramidal projection 6 having the inclination angle θ as described above but also the inclination angle θ is θ≈54 ° as shown in FIG. )
It also includes a quadrangular pyramid-shaped protrusion 6 ₁ whose surface faces the joint surface 4 a side.

Table 4 shows the relationship between the area ratio of the pyramidal projections 6 and 6 _{1 on} the joint surface 4a and the peel strength of the surface layer 5.

The peel strength was judged by measuring the peel width, and the peel width was measured by making cuts w in a checkerboard pattern on the surface layer 5, as shown in FIG.
After heating at 0 ° C. for 6 hours, cooling in water, repeating this cycle for 5 cycles, and performing ultrasonic cavitation. After each operation such as ultrasonic wave cavitation, the portion 5 b surrounded by the cut w of the surface layer 5 is a barrier layer. When peeling from No. 4, the distance from the cut w to the contact portion y was measured, and the maximum distance was defined as the peel width z.

In Table 4, the inventions (1) to (4) are N
The i crystal has the (h00) plane orientation, and the inventions (5) to (7) correspond to the Ni crystal having the (111) plane orientation.

[0041]

[Table 4] As is clear from Table 4, the surface layers in the present inventions (1) to (7) have excellent peel strength as compared with those in Comparative Examples (1) and (2). In order to obtain such peel strength, the area ratio of the quadrangular pyramidal protrusions 6 on the joint surface 4a is set to 1
It is preferable to set it to 5% or more (in this case, the balance is Ni alloy granular crystals).

FIG. 14 shows another embodiment of the barrier layer 4
Has a plurality of fine pyramid-shaped projections 10 made of Ni crystals, that is, a plurality of fine metal crystals with the upper bottom surface c directed toward the bonding surface 4a so as to form the bonding surface 4a. The present invention, the barrier layer 4 is quadrangular pyramid-shaped projections 6, 6 ₁ and truncated pyramid-shaped projections 1
The case of having 0 is also included.

When at least a part of the bonding surface 4a is formed from the upper bottom surface c of the quadrangular truncated pyramidal crystal 10 as described above, there is an advantage that the (h00) plane orientation of the surface layer 5 can be promoted.

In the surface layer 5, in order to form the sliding surface 5a, the quadrangular pyramid-shaped protrusions 11 (FIG. 16) are formed by a plurality of metal crystals with the upper bottom surface d facing the sliding surface 5a side, that is, Pb alloy crystals. (See) may be provided. Also the surface layer 5
May include both the quadrangular pyramid-shaped protrusion 8 and the quadrangular pyramid-shaped protrusion 11.

According to this structure, at least a part of the sliding surface 5a is formed by the upper bottom surface d of the truncated pyramid-shaped projection 11, so that the mating member x and the upper bottom surface d are formed from the beginning of the sliding operation.
An oil film can be formed between the surface layer 5 and the surface layer 5 to improve the initial conformability and to stabilize the surface.
Can have sufficient oil retention.

The pyramidal protrusions 8 and / or the truncated pyramidal protrusions 11 may form a part of the sliding surface 5a.
In this case, the area ratio of the projections 8 and 11 on the sliding surface 5a is set to 50% or more (in this case, the rest is granular crystals of Pb alloy).

In order to obtain excellent sliding characteristics as described above, the inclination of the quadrangular pyramidal projections 8 and the truncated quadrangular pyramid projections 11 becomes a problem.

Therefore, as shown in FIGS. 10 and 15, on the bottom surface side of the quadrangular pyramidal projection 8, the projection 8 is projected to define an imaginary plane E along the sliding surface 5a. Protrusion 8
A straight line h passing through the apex b of the
If the tilt angle with respect to the reference line k that passes through and is perpendicular to the virtual plane E is defined as θ, the tilt angle θ of the quadrangular pyramidal projection 8 is 0 ° ≦
θ ≦ 30 ° is set. When the inclination angle θ becomes θ> 30 °, the oil retaining property of the surface layer 5 and the preferential wear property on the apex b side are deteriorated.

The inclination angle θ in the case of the truncated pyramidal projection 11 is
As shown in FIG. 16, it is defined as an angle formed by a straight line r passing through the upper bottom central portion n and the lower bottom central portion p and a reference line k passing through the lower bottom central portion p and perpendicular to the virtual plane E. Also in this case, the inclination angle θ is set to 0 ° ≦ θ ≦ 30 °.

In the above-mentioned embodiment, the barrier layer and the surface layer were deposited and formed by the electroplating method, but other forming methods include PVD, ion plating, CVD, sputtering and other vapor phase forming methods. You can

The present invention is not limited to sliding bearings, but can be applied to other sliding members.

[0052]

According to the present invention, by specifying the structure of the barrier layer as described above, it is possible to provide a sliding member in which the peel strength of the surface layer from the barrier layer is improved.

[Brief description of drawings]

FIG. 1 is an exploded plan view of a plain bearing.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3A is a micrograph showing a crystal structure of Ni on a bonding surface, and FIG. 3B is a schematic view of FIG.

FIG. 4 is a main part schematic perspective view showing a first example of a barrier layer.

FIG. 5 is an X-ray diffraction diagram of Ni crystal in the first example of the barrier layer.

FIG. 6 is a micrograph showing a crystal structure of Ni on a bonding surface of a conventional example.

FIG. 7 is an X-ray diffraction diagram of Ni crystal in a conventional barrier layer.

FIG. 8 is a micrograph showing a crystal structure of a Pb alloy on a sliding surface.

FIG. 9 is a micrograph showing a crystal structure of a Pb alloy when a surface layer is longitudinally cut.

FIG. 10 is a schematic perspective view of a main part of a surface layer.

FIG. 11 is an X-ray diffraction diagram of Pb alloy crystals in the surface layer.

FIG. 12 is an explanatory diagram showing types of quadrangular pyramidal protrusions in the barrier layer.

FIG. 13 is an explanatory diagram of a peeling test.

FIG. 14 is a schematic perspective view of a main part showing a second example of a barrier layer.

FIG. 15 is an explanatory diagram showing a method for measuring a tilt angle of a quadrangular pyramidal protrusion on a surface layer.

FIG. 16 is an explanatory diagram showing a method for measuring an inclination angle of a quadrangular truncated pyramid-shaped projection on a surface layer.

[Explanation of symbols]

1 sliding bearing (sliding member) 4 barrier layer 4a bonding surface 5 surface layer 5a sliding surface 6,6 ₁ quadrangular pyramidal protrusion 10 quadrangular pyramid protrusion x mating member

Claims (2)

[Claims] 1. A sliding member in which a surface layer (5) is provided on a lining layer (3) via a metal barrier layer (4), wherein the barrier layer (4) is on the lining layer (3). It is one that is deposited formed, sliding, characterized in that it has to form a junction surface between said surface layer (5) (4a), a plurality of projections due to the metal crystals (6,6 _1, 10) Moving member. 2. A sliding member comprising a metal surface layer (5) provided on a lining layer (3) via a metal barrier layer (4), wherein the barrier layer (4) is the lining layer (3). ) Is formed by deposition on the surface layer (5) to form a joint surface (4a) with the surface layer (5). (6, 6 ₁ , 10), and the surface layer (5)
Is deposited and formed on the lining layer (3), and in order to form a sliding surface (5a) with the mating member (x), the (h00) surface is set to the sliding surface side with a Miller index. A sliding member having a plurality of directed metal crystals.