JP2607983B2 - 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-Sn 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 conventional plain bearing has oil on its surface layer. 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 provides the surface layer with sufficient oil retention by specifying the structure of the surface layer.
It is another object of the present invention to provide the sliding member in which the initial conformability of the surface layer is improved and thereby the seizure resistance of the surface layer is improved.

[0005]

According to the present invention, there is provided a sliding member provided with a surface layer having a sliding surface with a mating member, wherein the surface layer is formed by a plating method.
Having a plurality of columnar crystals grown with the orientation of
Tip of the columnar crystal, the a sliding surface along a virtual plane projects from the sliding surface formation to that square pyramidal crystals, the area rate A of the pyramid-shaped crystals at the sliding surface A ≧ 50%, and all of the pyramid-shaped crystals are defined as θ when the inclination angle formed by a straight line passing through the vertex and the center of the bottom surface of the pyramid-shaped crystal with respect to a reference line perpendicular to the virtual plane is θ. Angle of inclination θ
Is characterized by 0 ° ≦ θ ≦ 30 °.

[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 ,
Reference numeral ₁₂ has the same structure, and includes a substrate 2 and a surface layer 3 formed on the inner peripheral surface side of the substrate 2 and having a sliding surface 3a with the counterpart member x. Substrate 2 and the backing metal 2 _1, Part backing metal 2 ₁
It is formed on and has a lining layer 2 ₂ for supporting the surface layer 3. Between backing metal 2 ₁ and the lining layer 2 _second copper plating layer, also between the lining layer 2 ₂ and the surface layer 3 provided as necessary nickel plating barrier layer, respectively.

[0007] backing metal 2 ₁ is composed of rolled steel plate, the thickness thereof is determined by setting the thickness of the sliding bearing 1. Lining layer 2 ₂ copper, copper-based alloys, aluminum, is composed of aluminum alloy or the like and has a thickness of 50~500μ
m, usually about 300 μm. The surface layer 3 is made of a Pb alloy and has a thickness of 5 to 50 μm, usually 20 μm.
m.

The Pb alloy constituting the surface layer 3 is 80 to 9
It contains 0% by weight of Pb and 3 to 20% by weight of Sn, and optionally contains Cu, In, Ag, Tl, Nb, Sb, and N.
At least one selected from i, Cd, Te, Bi, Mn, Ca, and Ba is contained in an amount of 10% by weight or less.

[0009] Although Cu, Ni and Mn have a function of improving the hardness of the surface layer 3, if the content exceeds 10% by weight, the hardness becomes too high and the initial conformability decreases.
When Cu or the like is added, the hardness Hmv of the surface layer 3 is 1
It is desirable to adjust the content so as to be 5 to 25. The hardness Hmv of the surface layer 3 does not depend only on the content of Cu or the like, but is also affected by the orientation state of the crystal plane of the Pb alloy crystal as described later.

In, Ag, Tl, Nb, Sb, Cd, T
e, Bi, Ca, and Ba have a function of softening the surface layer 3 and improving initial conformability, but if the content exceeds 10% by weight, the strength of the surface layer 3 is reduced. When adding In or the like, it is desirable to adjust the content thereof so that the hardness Hmv of the surface layer 3 becomes 8 to 15.

The surface layer 3 is formed by an electroplating method, and a plating solution is 40 to 1 per liter.
80 g of Pb ²⁺ , 1.5 to 35 g of Sn per liter
^2+, borofluoride based plating solution comprising the following Cu ²⁺ 15 g per liter, are used as occasion demands. The temperature of the plating solution is 10 to 35 ° C., and the cathode current density is 3 to 15 A / d.
Each is set to m ^2.

FIG. 3 is an electron micrograph (× 10,000) showing the crystal structure of the Pb alloy when the sliding surface 3a is viewed from directly above.
From this figure, it can be seen that the surface layer 3 has a plurality of pyramidal crystals forming the sliding surface 3a, in the illustrated example, quadrangular pyramid crystals. In this case, the area ratio A of the quadrangular pyramidal crystal on the sliding surface 3a is A = 100%. Surface layer 3 is 8
It consists of a Pb alloy containing 2% by weight of Sn and 2% by weight of Cu. The surface layer 3 is formed on the copper alloy lining layer 2 _2, cathode current density in the electroplating process for forming the surface layer 3 was set to 6A / dm ^2.

FIG. 4 is an X-ray diffraction diagram of the Pb alloy crystal in the surface layer 3, where only the diffraction peaks of the (200) plane and the (400) plane are recognized by the Miller index.

Here, the orientation index O representing the abundance of the crystal plane oriented in the direction orthogonal to the (hkl) plane by the Miller index.
e (However, hkl is Miller index, Ihkl is (hkl)
Defined as the integrated intensity of the plane, ΣIhkl is the sum of Ihkl), in the (hkl) plane, its orientation index Oe is 1
The closer to 00%, the greater the abundance of crystal planes oriented in the direction perpendicular to the (hkl) plane.

The (200) plane and the (40) plane of the Pb alloy crystal
Table 1 shows the integrated intensity Ihkl and the orientation index Oe on the 0) plane.

[0016]

[Table 1]

According to Table 1, the orientation index Oe of the (h00) plane of the Pb alloy crystal is 100%.
The alloy crystal has crystal planes oriented in each axial direction at crystal axes a, b, and c, that is, (h00) plane. As described above, when the crystal plane is oriented in a direction orthogonal to the (h00) plane, since the crystal structure of the Pb alloy is a face-centered cubic structure, the atomic density in the orientation direction increases, and the hardness of the surface layer 3 is increased. And the seizure resistance is improved.

FIG. 5 is an electron micrograph (5,000-fold) showing the crystal structure when the surface layer 3 is longitudinally cut, and FIG.
This corresponds to a partially enlarged electron micrograph of FIG. 5 and 6
More, the surface layer 3 from the lining layer 2 _2, such as the
It can be seen that it is composed of an aggregate of columnar crystals grown with the orientation of the crystal plane .

FIG. 7 is an electron micrograph (10,000) showing the crystal structure of the Pb alloy when the sliding surface 3a is viewed obliquely from above.
Times).

As is clear from FIGS. 3 and 5 to 8, the pyramidal crystal 5 forms the tip of the columnar crystal 4 with the apex a directed toward the sliding surface 3a. Most of the body crystals 5 are growing straight, but the remaining few are slightly inclined.

Here, as shown in FIGS. 8 and 9, a virtual plane B along the sliding surface 3a is defined on the bottom surface side of the quadrangular pyramid-shaped crystal 5, and the vertex a If the inclination angle between the straight line c passing through the bottom center part b and the reference line d passing through the bottom center part b and perpendicular to the virtual plane B is defined as θ, the angle shown in FIGS. All of pyramidal crystals 5 (100%)
Has a tilt angle θ ≒ 0 °, and therefore each of the pyramidal crystals 5 has been found to be substantially straight.

The reason why the sliding surface 3a is formed from the quadrangular pyramid-shaped crystal 5 as described above is that the surface area of the sliding surface 3a is enlarged so that the surface layer 3 has a sufficient oil retaining property, and It is to improve the initial conformability of the surface layer 3 by preferentially abrading the vertex a side of the crystalline crystal 5.

In order to obtain such an effect, the range of the inclination angle θ of the quadrangular pyramidal crystal 5 becomes a problem. Therefore, the inclination angles θ of all the pyramidal crystals 5 are θ５0 °, 10 °,
20 °, 30 °, 40 °, 50 °, 60 °, 70 °, a plain bearing having an orientation index Oe of 100% on the (h00) plane, and an orientation index Oe of 50 to 55% on the (h00) plane. Were manufactured, and a seizure test was performed on those slide bearings. As a result, the results shown in FIG. 10 were obtained. In the figure, the line e indicates that the orientation index Oe is 10
0%, and the line f indicates that the orientation index Oe is 50 to 5
This corresponds to the case of 5%. In this case, the sliding surface 3a
Is, the area ratio A of the quadrangular pyramidal crystals 5 is A = 100%
It is. The change in the tilt angle θ is basically achieved by changing the tilt of the substrate 2 with respect to the anode.

The seizure test was performed by rubbing each sliding bearing against the rotating shaft and gradually increasing the load applied to the sliding bearing. FIG. 10 shows the surface pressure when the surface layer of each slide bearing is seized.

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

FIG. 10 shows that all the pyramidal crystals 5
It can be seen that when the orientation index Oe in the (h00) plane is 100% and the inclination angle θ is 0 ° ≦ θ ≦ 30 °, the surface pressure at which seizure occurs is increased and the seizure resistance is improved. In the case of the line f, the seizure resistance is lower than that in the case of the line e due to the low orientation index Oe .

In the quadrangular pyramid-shaped crystal 5, when the preferential abrasion on the vertex a side is completed at the beginning of the sliding and a flat surface (corresponding to the upper bottom surface of the truncated pyramid) is formed, the flat surface Since the oil film is always present between the rotating shaft and the rotating shaft, the sliding surface 3a thereafter wears extremely slowly.

Tables 2 to 4 show sliding bearings (1) to (8).
Shows the relationship between the inclination angle θ of the quadrangular pyramid-shaped crystal 5, the orientation direction, and the area ratio A on the sliding surface 3a.

In each of Tables 2 to 4, the orientation direction (h00)
Means that the orientation index Oe on the (h00) plane is 100%, and (11) has (11)
Not only the 1) plane but also the (222) plane, the (220) plane, and the (3) plane.
11) Surfaces are also included. In a Pb alloy crystal, (h
When the orientation index Oe on the (00) plane decreases, (11)
The orientation index in the 1) plane tends to increase, and the degree of the increase is extremely low as compared with the increase in the orientation index Oe in the (111) plane, but the (220) plane and the (311) plane.
The orientation index Oe in a plane or the like also increases.

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

FIG. 11 is an electron micrograph (× 10,000) showing the crystal structure of the Pb alloy when the sliding surface 3a of the plain bearing (6) in Table 4 is viewed obliquely from above, and FIG.
Shows the inclination of the quadrangular pyramidal crystal in FIG. Quadrangular pyramid-shaped crystals 5 _1, 5 _2, 5 ₃ inclination angle θ of,
Θ ≒ 0 °, 15 °, and 30 °, respectively. FIG.
From the fact that there are quadrangular pyramid crystals with different heights
I understand.

FIG. 13 shows the relationship between the area ratio of quadrangular pyramidal crystals having an inclination angle θ of 0 ° ≦ θ ≦ 30 ° and the surface pressure at which seizure occurs. The burn-in test was performed by the same method and under the same conditions as described above. In the figure, the line g indicates that the inclination angle θ is 0 ° ≦ θ ≦ 1.
This applies to the case of 0 ° quadrangular pyramidal crystals, which include the sliding bearings (1) to (4) in Table 2, which are point (1).
To (4). Line h indicates that the inclination angle θ is 0 ° ≦ θ.
This applies to the case of quadrangular pyramidal crystals of ≦ 20 °, which includes the plain bearing (5) of Table 3, which is indicated by the point (5). The line k corresponds to the case of a quadrangular pyramidal crystal having a tilt angle θ of 0 ° ≦ θ ≦ 30 °, which includes the sliding bearings (6) to (8) in Table 4 and includes the points ( 6) to (8).

A line m shows a comparative example in which the sliding surface is formed of a granular crystal of a Pb alloy. FIG. 14 is an electron micrograph (× 10,000) showing the crystal structure of the Pb alloy when the sliding surface of the comparative example is viewed from directly above, and it can be seen that the crystal form is random. FIG. 15 is an electron micrograph (10,000) showing the crystal structure of the Pb alloy when the comparative example surface layer was longitudinally cut.
Times) and no columnar crystals are formed.

As is clear from FIG. 13 and Tables 2 to 4, the orientation direction (h00) of the quadrangular pyramid-shaped crystal, that is, the orientation index Oe in the (h00) plane is 100%.
If the area ratio A of the quadrangular pyramidal crystals 5 on the sliding surface 3a is A ≧ 50% and the inclination angle θ of the quadrangular pyramidal crystals 5 is 0 ° ≦ θ ≦ 30 °, the surface The seizure resistance of the layer 3 can be greatly improved.

FIGS. 16 and 17 show that the surface layer 3 has the sliding surface 3.
The figure shows a case where a plurality of truncated pyramid-shaped crystals forming a, that is, a truncated pyramid-shaped crystal 6 of a Pb alloy is shown in the illustrated example, and the truncated pyramid-shaped crystal 6 faces the upper surface 7 toward the sliding surface 3a. Columnar crystals 4
Is formed. This columnar crystal 4 is, as described above,
It is grown with the orientation of the crystal plane. In this case, the inclination angle θ is defined as an angle formed by a straight line r passing through the upper bottom center n and the lower bottom center p and a reference line d passing through the lower bottom center p and perpendicular to the virtual plane B. Four like this
The truncated pyramidal crystal 6 wears the vertex a side of the quadrangular pyramidal crystal 5.
Formed.

In the case where the surface layer 3 has only the truncated pyramid crystal 6, and in the case where the surface layer 3 has the quadrangular pyramid crystal 5 and the truncated pyramid crystal 6, the truncated pyramid crystal 5 or the like on the sliding surface 3 a Is A ≧ 50%, and the inclination angle θ is 0
° ≦ θ ≦ 30 °, whereby the same sliding characteristics as described above can be obtained. In this case, the sliding surface 3
Since at least a portion of a is formed from the upper bottom surface 7 of the truncated quadrangular pyramid crystal 6, an oil film is formed between the mating member and the upper bottom surface 7 from the initial stage of sliding to improve initial adaptability. And can be stabilized . If the table surface layer 3 has both crystal 5 and 6, their total area and the sliding surface 3a
And the area ratio A is determined. In addition, the truncated pyramid shape
The surface layer 3 having only the crystal 6 has a plurality of substantially equal heights.
The surface layer 3 having the quadrangular pyramidal crystals 5 is subjected to polishing.
And can be easily obtained by
The surface layer 6 having the truncated quadrangular pyramid crystal 6 has multiple layers of different heights.
Surface layer 3 having a number of pyramidal crystals 5
Can be obtained easily.

Quadrangular pyramidal crystal 5 and truncated quadrangular pyramid crystal 6
Is inclined, it is preferable to incline so that the vertex a or the upper bottom surface 7 is located in front of the mating member in the sliding direction s as shown in FIGS. This is to reduce the sliding resistance between the mating member and the quadrangular pyramidal crystal 5 or the like.

In the above embodiment, the surface layer 3 was formed by the electroplating method.
Gas phase plating methods such as PVD, ion plating, CVD, and sputtering can be used .

The present invention is naturally applied to sliding members other than slide bearings.

[0042]

According to the present invention, by specifying the structure of the surface layer as described above, the hardness of the surface layer and the oil retention
And initial familiarity, respectively,
Thereby, it is possible to provide a sliding member having significantly improved seizure resistance of the surface layer .

[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 micrograph showing a crystal structure of a Pb alloy when a first example of a sliding surface is viewed from directly above.

FIG. 4 is an X-ray diffraction diagram of a Pb alloy crystal in a first example of the surface layer.

FIG. 5 is a photomicrograph showing a crystal structure of a Pb alloy when a first example of a surface layer is longitudinally cut.

FIG. 6 is a partially enlarged micrograph of FIG. 5;

FIG. 7 shows Pb when the first example of the sliding surface is viewed obliquely from above.
3 is a micrograph showing a crystal structure of an alloy.

FIG. 8 is a schematic perspective view of a main part showing a first example of a surface layer.

FIG. 9 is an explanatory view showing a method for measuring the inclination angle of a quadrangular pyramid crystal.

FIG. 10 is a graph showing the relationship between the tilt angle and the surface pressure at which seizure occurs.

FIG. 11 is a diagram showing a P when a second example of the sliding surface is viewed from obliquely above.
4 is a micrograph showing a crystal structure of an alloy b.

FIG. 12 is a schematic side view of a main part showing a second example of the surface layer.

FIG. 13 is a graph showing the relationship between the area ratio of quadrangular pyramidal crystals having a tilt angle θ of 0 ° ≦ θ ≦ 30 ° and the surface pressure at which image sticking occurs.

FIG. 14 is a micrograph showing the crystal structure of a Pb alloy when the sliding surface of the comparative example is viewed from directly above.

FIG. 15 is a photomicrograph showing a crystal structure of a Pb alloy when a comparative example surface layer is longitudinally cut.

FIG. 16 is a schematic perspective view of a main part showing a third example of the surface layer.

FIG. 17 is an explanatory view showing a method for measuring the inclination angle of a truncated pyramid crystal.

[Explanation of symbols]

3 surface layer 3a sliding surface 5 quadrangular pyramid-shaped crystals (pyramid-shaped crystals) 6 quadrangular pyramid-shaped crystals (truncated pyramid crystals) B imaginary surface a vertex b bottom central portion c, on r linearly d reference line n bottom Center p Lower center of bottom x Counterpart

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-47589 (JP, A) JP-A-56-51589 (JP, A) JP-A-56-84435 (JP, A)

Claims (3)

(57) [Claims] 1. A sliding member having a surface layer (3) having a sliding surface (3a) with a mating member (x), wherein said surface layer (3) is formed by plating. ,crystal
Has a plurality of columnar crystals (4) grown with plane orientation
The tip of the columnar crystal (4) is connected to the sliding surface (3).
a), which protrudes from a virtual surface (B) along the sliding surface (3).
a you form a) square pyramidal crystals (5), the area rate A of the pyramid-shaped crystals at the sliding surface (3a) (5) is A ≧ 50%, also the pyramid-shaped When a straight line (c) passing through the apex (a) of the crystal (5) and the center part (b) of the bottom surface forms an inclination angle θ with respect to a reference line (d) perpendicular to the virtual plane (B), A sliding member , wherein the inclination angles θ of all the pyramidal crystals (5) are 0 ° ≦ θ ≦ 30 °. 2. It has a sliding surface (3a) with a mating member (x).
A sliding member provided with one surface layer (3);
(3) isCrystal formed by plating method
Has a plurality of columnar crystals (4) grown with plane orientation
And the tip of these columnar crystals (4)The sliding surface (3
a), which protrudes from a virtual surface (B) along the sliding surface (3).
form a)CornerFrustum shapecrystal(6)Is, The sliding surface
The truncated pyramid shape in (3a)crystalThe area ratio A of (6) is
A ≧ 50% and the truncated pyramid shapecrystal(6) Top bottom
Straight line (r) passing through the center (n) of the surface and the center (p) of the lower bottom surface
Does not match the reference line (d) perpendicular to the virtual plane (B).
When the inclination angle is θ,All ofThe truncated pyramidcrystal
The inclination angle θ in (6) is 0 ° ≦ θ ≦ 30 °.
Sliding member to be featured. 3. It has a sliding surface (3a) with a mating member (x).
A sliding member provided with one surface layer (3);
(3) isCrystal formed by plating method
Has a plurality of columnar crystals (4) grown with plane orientation
The columnar crystals (4) have, The sliding surface
The sliding surface protruding from an imaginary surface (B) along (3a);
Form (3a)CornerCone shapecrystal(5)And
The tip is from the virtual surface (B) along the sliding surface (3a).
A corner that protrudes to form the sliding surface (3a)Frustum shapecrystal
(6)And what is included, On the sliding surface (3a)
Pyramidal shapecrystal(5) and the truncated pyramid shapecrystal
(6)BothArea ratioSum ofA is A ≧ 50%, and
Pyramid shapecrystalThe vertex (a) of (5) and the bottom center (b)
The straight line (c) passing through and the upper and lower surfaces of the truncated pyramidal crystal (6)
Straight line (r) passing through the center (n) and the center (p) of the lower bottom surface
Does not match the reference line (d) perpendicular to the virtual plane (B).
When the inclination angle is θ,All ofThe pyramid shapecrystal
(5) andAll ofThe truncated pyramidcrystal(6) tilt angle θ
IsRespectively0 ° ≦ θ ≦ 30 °
Sliding member.