JP2657335B2 - Sliding member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding member, and more particularly to a sliding member having a surface layer having a sliding surface with a mating member.

[0002]

2. Description of the Related Art Conventionally, as this kind of sliding member, there has been known a sliding bearing in which the surface layer is made of a Pb alloy (see Japanese Patent Application Laid-Open No. 56-96088).

[0003]

Problems to be Solved by the Invention This type of plain bearing is
It is applied to the journal part of the crankshaft, the large end of the connecting rod, etc. in the engine. However, in the current situation where the engine tends to be high-speed and high-power, the surface layer of the conventional plain bearing is oil There is a problem that the retention property, that is, the oil retention property is not sufficient, and the seizure resistance is poor due to poor initial conformability.

[0004] In view of the above, the present invention specifies the content and crystal structure of an alloy element in a surface layer,
It is an object of the present invention to provide the sliding member in which the surface layer has a sufficient oil retaining property and the initial conformability of the surface layer is improved, thereby improving the seizure resistance of the surface layer.

[0005]

Means for Solving the Problems The present invention provides a sliding member having a surface layer having a sliding surface with a mating member, wherein the surface layer is composed of crystal aggregates of P b alloy, the Pb case
Gold is composed of Sn, an essential alloying element, and first and second selections.
Contains at least one selected from alternative alloying elements
And the content of Sn is 17% by weight or less,
Alloying elements Cu, Ni, Fe, Cr, Mn, C
o, Sb, Cd, Bi and Ca
The content of one kind is not more than 5% by weight,
Alloy elements Ag, Nb, Te, Ba, In and T
at least one content selected from the group consisting of 10% by weight
In accordance with the X-ray diffraction method applied to the surface layer, the integrated intensity of the first oriented crystal with the (h00) plane facing the sliding surface is set as I (a), and the Miller index is set. in (111) plane and (222) when the surface second oriented crystals towards the sliding surface side of the integrated intensity of the (5 ₂₎ was I (b), 0.5 ≦ I (a) / ΣI (ab ) ≦ 1.0 (where ΔI (ab) = I (a) + I (b).
(including (b) = 0).

[0006]

1 and 2, a sliding bearing 1 as a sliding member is applied to a journal portion of a crankshaft, a large end portion of a connecting rod and the like in an engine.
The first and second halves ₁ 1, consisting of 1 _2. Both halves 1 ₁ ,
1 ₂ has the same structure, and has a back metal 2, a lining layer 3 formed on the inner peripheral surface of the back metal 2, and a sliding surface 4 a formed on the surface of the lining layer 3 and mating with the member x. And a surface layer 4. The surface layer 4 is formed by an electroplating method, a Cu plating layer is provided between the back metal 2 and the lining layer 3, and the lining layer 3 and the surface layer 4 are formed.
A Ni plating barrier layer is provided between the layers as needed.

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, Cu-based alloy, Al, Al-based alloy, etc., and has a thickness of 50 to 500 μm, usually 300 μm.
m. The surface layer 4 is composed of a crystal aggregate of a Pb alloy and has a thickness of 5 to 50 μm, usually about 20 μm.

The Pb alloy constituting the surface layer 4 contains Sn as an essential alloy element, and if necessary, contains Cu, F
e, Cr, Co, In, Ag, Tl, Nb, Sb, N
It contains at least one selected from i, Cd, Te, Bi, Mn, Ca, and Ba. Sn has a function of improving the strength of the surface layer 4. Cu, Ni, Mn, F
e, Cr, and Co have a function of improving the hardness of the surface layer 4. Further, In, Ag, Tl, Nb, Sb, Cd,
Te, Bi, Ca, and Ba have a function of softening the surface layer 4 and improving initial conformability.

The surface layer 4 has a first oriented crystal in which the (h00) plane is directed toward the sliding surface with a Miller index so as to form the sliding surface 4a. The first oriented crystal has a function of improving the sliding characteristics of the surface layer 4. The surface layer 4 has a (111) plane and a (22)
2) There may be a second oriented crystal whose surface faces the sliding surface.

In the Pb alloy crystal, if one of the (h00) plane and the (111) plane (including the (222) plane) increases, the other decreases. Therefore, the surface layer 4 has the first layer. Unless it is composed of only oriented crystals,
The first and second oriented crystals must be considered in correlation.

In consideration of this point, the first surface layer 4
The abundance of oriented crystals is set as follows.

That is, under the application of the X-ray diffraction method to the surface layer 4, the first (h00) plane with the Miller index facing the sliding surface side.
When the integrated intensity of the oriented crystal is I (a), and the Miller index is I (b), the integral intensity of the second oriented crystal with the (111) plane and the (222) plane facing the sliding surface is 0. 5 ≦ I (a) / I (ab) ≦ 1.0 (where ΔI (ab) = I (a) + I (b), and I
(b) = 0). Where I (a) / I
(ab) is the abundance R ₁ of the first oriented crystal.

[0013] As shown in FIGS. 2 4, (h00) a first oriented crystals 5 ₁ with its surface on the sliding surface side, lining layer 3
And has a quadrangular pyramid-shaped tip 6 forming a sliding surface 4a.

[0014] The presence rate R ₁ of such a first oriented crystals 5 ₁
Is set as described above, the vertex a side of the quadrangular pyramid-shaped tip 6 can be preferentially worn to improve the initial conformability of the surface layer 4. By increasing the surface area of the sliding surface 4a, the surface layer 4 can have a sufficient oil retaining property. Thereby, the seizure resistance of the surface layer 4 can be improved.

[0015] As the (h00) face orientation, since the first oriented crystals 5 ₁ is a face-centered cubic structure, the atom density becomes higher in the orientation direction, said oil retention with hardness of the surface layer 4 is increased As a result, the wear resistance of the surface layer 4 can be improved. 3, 4, 5 ₂ is a second oriented crystals exhibit granular crystals.

[0016] In order to obtain excellent sliding characteristics as described above, the first oriented crystals 5 ₁ slope becomes a problem.

Therefore, as shown in FIG. 5, the tip 6 protrudes from the bottom surface of the quadrangular pyramid tip 6 so that the sliding surface 4a is formed.
Is defined, and a straight line d passing through the vertex a of the quadrangular pyramid-shaped tip portion 6 and the bottom center portion c is formed with respect to a reference line e passing through the bottom center portion c and perpendicular to the virtual surface B. When defining the inclination angle and theta, the inclination angle theta first oriented crystals 5 ₁ 0 ° ≦ θ ≦
It is set to 30 °. When the inclination angle θ becomes θ> 30 °,
The oil retaining property of the surface layer 4 and the preferential abrasion on the vertex a side decrease, and the seizure resistance and the abrasion resistance of the surface layer 4 decrease.

[0018] In the composition surface of the surface layer 4, Sn content is an essential alloy element affects the existence rate R ₁ of the first oriented crystals 5 _1.

[0019] Figure 6 shows the relationship between the presence ratio R ₁ of the Sn content and the first oriented crystals 5 _1. 6, as is apparent from the solid line f _1, the presence rate R ₁ by setting the Sn content 17% by weight or less can be kept less than 0.5. The preferred range of the Sn content is 3% by weight or more,
% By weight or less.

[0020] FIG. 6, the dotted line f ₂ is the outer surface layer of the first and second oriented crystals 5 _1, 5 _2, shows a case where a third oriented crystals adversely affect the sliding characteristics. Will be described later in this third oriented crystals, by setting the abundance ratio R ₂ to 0.2 or less, the results shown by the dotted line f ₂ is obtained.
Also in this case, the Sn content is set in the same manner as described above.

When the surface layer 4 is formed by the electroplating method, a plating solution of 40 to 180 g per liter is used.
Pb ²⁺ of, Sn ²⁺ per liter 1.5～35G, borofluoride based plating solution containing 15g following Cu ²⁺ and additive per liter are used as occasion demands. As the additive, an organic additive is used, and the organic additive is selected from hydroquinone, quinone compounds such as catechol, gelatin, amino acid compounds such as peptone, and aldehydes such as benzaldehyde and vanillin. At least one is applicable. The total amount of the organic additives is 1.5 to 18 g per liter. Boric hydrofluoric acid and boric acid are added to the plating solution as needed to adjust the liquid resistance during energization. The temperature of the plating solution is 5 to 35 ° C., and the cathode current density is 3 to 15 A /
dm ² .

Hereinafter, specific examples will be described.

An electroplating process was performed on the Cu alloy lining layer 3 to form a surface layer 4 made of a crystal aggregate of a Pb alloy.

The electroplating conditions are as follows. Plating solution: 110 g Pb ²⁺ per liter, 10 g Sn ²⁺ per liter and 2.5 g C per liter
Boron fluorinated plating solution containing u ²⁺ ; additive: organic additive; plating solution temperature: 25 ° C .; current density: 6 A / dm ² .

The composition of the surface layer 4 was 90% by weight Pb, 8% by weight Sn, and 2% by weight Cu.

FIG. 7 is an X-ray diffraction diagram of the Pb alloy crystal in the surface layer 4, in which the peak g ₁ indicates the (200) plane and the peak g ₂ indicates the (400) plane. h00) plane. From this figure, it can be seen that the surface layer 4
, It was confirmed to be constituted by only the first oriented crystals 5 _1. In this case, the total integrated intensity ΣI (ab) is
(ab) = 679,996 (although, I (b) = 0) is equal to the first oriented crystals 5 ₁ of integrated intensity I (a). Thus, the presence rate R ₁ of the first oriented crystals 5 ₁ is R ₁ = 1.0.

FIG. 8 is an electron micrograph (× 10,000) showing the crystal structure of the Pb alloy on the sliding surface 4a.
Is a photomicrograph (5,000 times) showing the crystal structure of the Pb alloy when the surface layer 4 was cut longitudinally. 8, 9 that the surface layer 4 is composed of the first oriented crystals 5 _1, thus columnar crystals, also it can be seen that the sliding surface 4a is formed from the quadrangular pyramid-shaped tip 6. The first oriented crystals 5 ₁ tilt angle theta, is 0 ° ≦ θ ≦ 10 °.

FIG. 10 is an electron micrograph (× 10,000) showing the crystal structure of the Pb alloy on another sliding surface 4a. Outside the quadrangular pyramid-shaped tip 6 in the figure, granular crystals is observed as a second oriented crystals 5 _2.

[0029] In FIG. 10, the first oriented crystals 5 ₁ of integrated intensity I (a) is a I (a) = 37,172, and the second oriented crystals 5 ₂ of integrated intensity I (b) is I (b ) = 24,781. Thus, the presence rate R ₁ of the first oriented crystals 5 _1, R ₁ =
0.6. Also the inclination angle θ first oriented crystals 5 ₁ 0 °
≤ θ ≤ 10 °.

[0030] Figure 11, the surface layer 4 of the various sliding bearing 1, showing the relationship between the first oriented crystals 5 ₁ occurrence rate R ₁ and the seizure generating surface pressure. In the figure, the line h ₁ in the case of the first oriented crystals 5 ₁ tilt angle theta is 0 ° ≦ θ ≦ 10 °, the line h ₂ is first oriented crystals 5 ₁ of the tilt angle θ 0 ° ≦ θ ≦ 20 If the °, line h ₃ is first oriented crystals 5 ₁ of the tilt angle θ 0 ° ≦ θ ≦ 30 °
In each case.

In the seizure test, each sliding bearing 1 was attached to the rotating shaft.
, And the load applied to the sliding bearing 1 was gradually increased. FIG. 11 shows the surface pressure when the surface layer 4 of each sliding bearing 1 is seized.

The test conditions are as follows. Material of rotating shaft JIS S48C material subjected to nitriding treatment, rotation speed of rotating shaft 6000 rpm, lubrication temperature 120 ° C, lubrication pressure 3 kg / cm ² , load 1 kg / sec.

[0033] As is clear from FIG. 11, the presence rate R ₁ of the first oriented crystals 5 ₁ can be improved seizure resistance of the surface layer 4 by setting the R ₁ ≧ 0.5. The first preferred range of prevalence R ₁ of oriented crystals 5 ₁ 0.8 ≦
R ₁ ≦ 1.0. When R ₁ = 1.0, the best seizure resistance is exhibited.

In the surface layer 4, as described above, the third oriented crystal, ie, (h00) plane, (111) plane, (22)
In some cases, a Pb alloy crystal in which a crystal plane other than the 2) plane faces the sliding surface side is precipitated, and the crystal plane has a (220) plane, a (311) plane, a (331) plane, and a (331) plane with a Miller index. 4
20) planes are included. Since the third oriented crystal has an adverse effect on the seizure resistance of the surface layer 4, it is necessary to suppress the abundance thereof.

In consideration of these points, the abundance of the third oriented crystal in the surface layer 4 is set as follows.

That is, under the application of the X-ray diffraction method to the surface layer 4, the first (h00) plane with the Miller index turned to the sliding surface side.
The integrated intensity of the oriented crystals 5 ₁ and I (a), also the second integrated intensity of oriented crystals 5 ₂ towards the mirror index (111) plane and the (222) plane on the sliding surface side and I (b) , And (h
The integrated intensity of the third oriented crystal with the crystal planes other than the (00), (111) and (222) planes facing the sliding surface is represented by I (c).
I (c) / ΣI (abc) ≦ 0.2 (where ΔI (abc) = I (a) + I (b) + I (c), and includes I (b) = 0 ) Is established. Here, I (c) / ΣI (abc) is the abundance R ₂ of the third oriented crystal.

In terms of the composition of the surface layer 4, the selective alloying elements Cu, Ni, Mn, Fe, Cr, Co, S
The contents of b, Cd, Bi and Ca affect the abundance R ₂ of the third oriented crystal.

FIG. 12 shows the relationship between the Cu content and the abundance R ₂ of the third oriented crystals. As is clear from this figure, C
By setting the u content to 5% by weight or less, the abundance R ₂ can be kept at 0.2 or less. A preferred range of the Cu content is 1% by weight or more and 3% by weight or less. Ni
The content of other selective alloying elements also shows the same tendency as the Cu content.

FIG. 13 shows the relationship between the abundance ratio R ₂ of the third oriented crystal and the surface pressure at which seizure occurs in the surface layer 4 of each of the sliding bearings 1. The composition of the surface layer 4 is 90% by weight Pb, 8% by weight.
% By weight Sn and 2% by weight Cu. In the figure, line k _1, the presence rate R ₁ of the first oriented crystals 5 _1, than R ₁ = 1.0, thus I (b) = 0 is a the surface layer 4 and the first and third oriented crystals Be composed. The line k ₂ is the first oriented crystal 5 ₁
The existence ratio R ₁ is, the surface layer 4 is first a R ₁ = 0.8, second, composed of third oriented crystals. The image sticking test was performed under the same method and under the same conditions as described above.

As is clear from FIG. 13, the seizure resistance of the surface layer 4 can be improved by setting the abundance R ₂ of the third oriented crystal to R ₂ ≦ 0.2. Third
The abundance R ₂ of the oriented crystals preferably satisfies R ₂ ≦ 0.1. Note that R ₂ = 0 corresponds to a case where the third orientation crystal does not exist in the surface layer 4.

The optimum state of the surface layer 4 is first oriented crystals 5 ₁
Is 0 ° ≦ θ ≦ 10 °, and the abundance R ₁ is R ₁ = I (a) / ΣI (abc) ≧ 0.8.

In the selective alloying elements, Ag, N
The contents of b, Te, and Ba are set to 10% by weight or less to avoid a decrease in the strength of the surface layer 4.

In the above selective alloying elements, In,
When Tl is contained in the surface layer 4, a coating layer of In or the like is formed on the Pb alloy plating layer,
By performing a heat treatment at 15 ° C. for 15 to 60 minutes, In or the like is diffused into the Pb alloy plating layer and alloyed. If the content of In or the like is too large, the surface layer 4 is excessively softened, resulting in a decrease in the melting point and, consequently, a decrease in the strength of the surface layer 4. May be formed to cause delamination. Then I
The contents of n and Tl after diffusion are set to 0.5% by weight or more and 10% by weight or less. The adjustment of the content is performed by the thickness of the coating layer.

The present invention can be applied to sliding members other than plain bearings.

[0045]

According to the present invention, it is possible to provide a sliding member in which the seizure resistance of the surface layer is improved by specifying the content of the alloy element and the crystal structure in the surface layer as described above. .

[Brief description of the drawings]

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

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

FIG. 3 is a schematic view of a main part of a sliding surface.

FIG. 4 is a schematic longitudinal sectional view of a main part of a surface layer.

FIG. 5 is an explanatory view showing a method for measuring a tilt angle of a first oriented crystal.

FIG. 6 is a graph showing a relationship between a Sn content and an abundance of a first oriented crystal.

FIG. 7 is an X-ray diffraction diagram of a Pb alloy crystal on a surface layer.

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

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

FIG. 10 is a micrograph showing a crystal structure of a Pb alloy on another sliding surface.

FIG. 11 is a graph showing the relationship between the abundance of first oriented crystals and the surface pressure at which seizure occurs.

FIG. 12 is a graph showing the relationship between the Cu content and the abundance of third oriented crystals.

FIG. 13 is a graph showing the relationship between the abundance of third oriented crystals and the surface pressure at which seizure occurs.

[Explanation of symbols]

Reference Signs List 1 sliding bearing (sliding member) 4 surface layer 4a sliding surface 5 ₁ first oriented crystal 5 ₂ second oriented crystal x mating member

Claims (1)

(57) [Claims] 1. A sliding member having a surface layer having a sliding surface (4a) of the mating member (x) (4), wherein the surface layer (4) is composed of crystalline aggregate of P b Alloy , Its Pb
The alloy is composed of Sn, which is an essential alloy element, and first and second alloys.
Contains at least one selected from selective alloying elements
And the content of Sn is 17% by weight or less,
Alloying elements Cu, Ni, Fe, Cr, Mn, C
o, Sb, Cd, Bi and Ca
The content of one kind is not more than 5% by weight,
Alloy elements Ag, Nb, Te, Ba, In and T
at least one content selected from the group consisting of 10% by weight
X set for the surface layer (4)
Under the application of the X-ray diffraction method, the integrated intensity of the first oriented crystal (5 ₁ ) with the (h00) plane facing the sliding surface side is defined as I (a) by the Miller index, and the (111) plane and ( When the integrated intensity of the second oriented crystal (5 ₂ ) whose (222) plane faces the sliding surface is defined as I (b), 0.5 ≦ I (a) / I (ab) ≦ 1.0 (where , ΣI (ab) = I (a) + I (b), and I
(b) = a sliding member, characterized in that is established a relationship of 0 inclusive).