JPH059461A - Sliding member - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a slide bearing having excellent seizure resistance. [Constitution] Sliding surface 4a is a Pb alloy quadrangular pyramidal crystal 8
It is formed by the aggregate of. The oil groove 6 is formed on the sliding surface a.
Is open. As a result, the surface area of the sliding surface a is enlarged, and the sliding surface a has sufficient oil retaining property.
A smooth oil flow is performed and the oil is supplied from the oil groove 6 to the sliding surface a. Furthermore, since the apex c side of the quadrangular pyramidal crystal 8 is preferentially worn, the initial conformability of the sliding surface forming portion 5 becomes good.

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 sliding surface with a mating member and an oil groove opening on the sliding surface.

[0002]

2. Description of the Related Art Conventionally, a sliding bearing has been known as a sliding member of this kind, and its sliding surface is finished by cutting, grinding or the like.

[0003]

This type of sliding bearing is
It is applied to the journal part of the crankshaft, the large end part of the connecting rod, etc. in the engine, but under the current situation where the engine tends to be high speed and high output, the sliding surface forming part of the conventional slide bearing is , Its oil retention, that is, oil retention is not sufficient, and the oil flow is also insufficient,
In addition, there is a problem that seizure resistance is poor because initial conformability is poor.

In view of the above, the present invention specifies the structure of the sliding surface forming portion to provide the sliding surface forming portion with sufficient oil retaining property and smooth the oil flow. It is an object of the present invention to provide the above-mentioned sliding member having good initial conformability and improved seizure resistance.

[0005]

The present invention provides a sliding member having a sliding surface with a mating member and an oil groove opening in the sliding surface, wherein the sliding surface forming portion has a plurality of pyramids. And at least one of a plurality of truncated pyramidal projections.

[0006]

1 to 3, 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 is composed of first and second halves 1 ₁ and 1 ₂ having the same structure. Substrates ₂ of both halves 1 ₁ and 1 ₂ have a back metal 2 ₁ and a back metal 2 ₁
And a inner peripheral surface lining layer 2 ₂ formed of, that the lining layer 2 ₂ is formed such that a plurality of grooves 3 extending in the circumferential direction. The coating layer 4 is formed on the surface of the lining layer 2 ₂ and the inner surface of each groove 3, and the strip-shaped portion of the coating layer 4 existing on the lining layer 2 ₂ is a sliding surface that forms a sliding surface a with the mating member x. U that is the forming part 5 and exists in each groove 3
The letter-shaped portion is an oil groove inner surface forming portion 7 that defines an oil groove 6 that opens to the sliding surface a and forms an inner surface b thereof.

The back metal 2 ₁ is made of a rolled steel plate, and its thickness is determined by the set thickness of the slide bearing 1. Lining layer 2 ₂ Cu, Cu alloy, Al, is composed of Al-based alloy, its thickness is 50 to 500 [mu] m, usually 30
It is about 0 μm. The coating layer 4 is made of Pb alloy,
Its thickness is 5 to 50 μm, usually about 20 μm.
The oil groove 6 has a width of 0.01 to 0.5 mm and a depth of 0.01 to
It is about 0.1 mm.

The Pb alloy forming the coating layer 4 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 coating layer 4, but if the content thereof exceeds 10% by weight, the hardness becomes too high and the sliding surface forming portion 5 is initially familiar with the material. Sex decreases. When Cu or the like is added, the coating layer 4
It is desirable to adjust the content so that the hardness Hmv of 15 becomes 25 to 25.

In, Ag, Tl, Nb, Sb, Cd, T
e, Bi, Ca, and Ba have a function of softening the coating layer 4 to improve the initial conformability of the sliding surface forming portion 5, but if the content thereof exceeds 10% by weight, the strength of the coating layer 4 is increased. Is reduced. When In or the like is added, the hardness Hm of the coating layer 4
It is desirable to adjust the content so that v becomes 8 to 15.

The coating layer 4 is formed by an electroplating method, and the plating liquid is 40 to 1 per liter.
80 g Pb ²⁺ , 1.5-35 g Sn per liter
²⁺ , optionally less than 15g Cu ²⁺ per liter
A fluorinated plating solution containing is used. The temperature of the plating solution is 10 to 35 ° C. and the cathode current density is 3 to 15 A /
dm ² respectively.

FIG. 4 is an electron micrograph (10,000 times) showing the crystal structure of the Pb alloy on the surface of the sliding surface forming portion 5, and thus on the sliding surface a. FIG. 5 is a longitudinal section of the sliding surface forming portion 5. It is an electron micrograph (5,000 times) which shows the crystal structure of Pb alloy in the case of doing. The coating layer 4 is 8% by weight of S
nb and a Pb alloy containing 2% by weight of Cu,
The lining layer 2 ₂ is made of a Cu alloy. The cathode current density in the electroplating process for forming the coating layer 4 was set to 6 A / dm ² .

As shown in FIGS. 2 to 6, the sliding surface forming portion 5 has a plurality of pyramidal projections with the apex c directed toward the sliding surface a in order to form the sliding surface a. In the illustrated example, the Pb alloy has quadrangular pyramidal crystals 8. Each quadrangular pyramidal crystal 8 forms the tip of each columnar crystal 9 extending from the lining layer 2 _2. Therefore, the sliding surface forming portion 5 is composed of an aggregate of columnar crystals 9.

FIG. 7 is an X-ray diffraction diagram of the Pb alloy crystal in the sliding surface forming portion 5, and only the diffraction peaks of the (200) plane and the (400) plane are recognized by the Miller index.

Here, the orientation index Oe as an index representing the orientation of the crystal planes, (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 Pb alloy crystal
Table 1 shows the integrated intensity Ihkl and the orientation index Oe in the (0) plane.

[0017]

[Table 1]

From Table 1, the orientation index Oe on the (h00) plane of the Pb alloy is 100%, and therefore Pb
The alloy crystal has crystal planes oriented in the respective axial directions on the crystal axes a, b, and c, that is, the (h00) plane.

When the crystal plane is oriented in the direction orthogonal to the (h00) plane in this way, the crystal structure of the Pb alloy is a face-centered cubic structure, so that the atomic density in the orientation direction becomes high, so that sliding The hardness of the surface forming portion 5 is increased, and the seizure resistance and wear resistance thereof are improved.

The oil groove inner surface forming portion 7 also has the same crystal structure as the sliding surface forming portion 5.

Table 2 shows the seizure test results of the sliding bearings of the present invention and comparative examples. In both slide bearings, the width of the oil groove 6 is 0.15 mm, the depth is 0.03 mm, and the number is 6.
Books / 1 mm wide. The coating layer in the comparative slide bearing is composed of an aggregate of granular crystals of Pb alloy.

The seizure test was carried out by rubbing each slide bearing on the rotary shaft and gradually increasing the load applied to the slide bearing. Table 2 shows the surface pressure when seizure occurs in each slide bearing.

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

[0024]

[Table 2]

As is clear from Table 2, the sliding bearing of the present invention has excellent seizure resistance as compared with the sliding bearing of the comparative example. The reason why such an effect is obtained is that the apex c side of the quadrangular pyramidal crystal 8 forming the sliding surface a is preferentially worn to improve the initial conformability of the sliding surface forming portion 5. This is because the Pb alloy crystal is a quadrangular pyramidal crystal 8
Due to the fact that the sliding surface a has a large surface area, the sliding surface forming portion 5 has a sufficient oil retaining property, and on the sliding surface a, the two quadrangular pyramidal crystals are adjacent to each other. This is because the oil flows smoothly through the passages between 8 and the oil is supplied to the sliding surface a from each oil groove 6, so that the oil spreads over the entire sliding surface a and a good lubricating ability is obtained.
Further, the sliding surface a and the inner surface b of the oil groove exert an oil cooling action by increasing the surface area thereof, which also helps to increase the surface pressure at which seizure occurs.

When the preferential wear on the apex c side is completed and a flat surface (corresponding to the upper bottom surface of the truncated pyramid) is formed at the beginning of sliding, a flat surface (corresponding to the upper bottom surface of the truncated pyramid) is always present between the flat surface and the counterpart member. Due to the presence of the oil film, the subsequent wear of the sliding surface a is extremely slow.

8 and 9 (10,000 times electron micrograph)
Is a plurality of pyramidal truncated pyramidal projections whose upper bottom surface f is directed toward the sliding surface a in order to form the sliding surface a, that is, a truncated pyramidal crystal 10 of Pb alloy in the illustrated example. It shows the case of having only such a crystal 10, or such a crystal 10 and a quadrangular pyramidal crystal 8
A sliding structure similar to the above can be obtained by a hybrid structure of and. In this case, since at least a part of the sliding surface a is formed from the upper bottom surface f of the truncated pyramid crystal 10, an oil film is formed between the mating member and the upper bottom surface f from the initial stage of sliding start. It is possible to improve the conformability and stabilize it. The oil groove inner surface forming portion 7 also has a quadrangular truncated pyramid crystal 10 and the like.

The present invention also includes the case where the quadrangular pyramidal crystal 8 and / or the quadrangular pyramid crystal 10 forms a part of the sliding surface forming portion 5 and the oil groove inner surface forming portion 7. In this case, the area ratio of the quadrangular pyramidal crystals 8 and the like on the sliding surface a and the like is set to 50% or more, and the balance is granular crystals of Pb alloy and the like.

In order to obtain excellent sliding characteristics as described above, the inclination of the quadrangular pyramidal crystals 8 and the truncated quadrangular pyramid crystals 10 in the sliding surface forming portion 5 becomes a problem.

Therefore, as shown in FIGS. 6 and 10, on the bottom surface side of the quadrangular pyramidal crystal 8, the crystal 8 is projected to define an imaginary plane G along the sliding surface a. If the inclination angle of the straight line k passing through the vertex c of the crystal 8 and the bottom center part h with respect to the reference line m passing through the bottom center part h and perpendicular to the virtual plane G is defined as θ, the quadrangular pyramidal crystal 8 The tilt angle θ is 0 ° ≦ θ ≦
It is set to 30 °. When the inclination angle θ becomes θ> 30 °, the oil retaining property of the sliding surface forming portion 5 and the preferential wear property on the apex c side decrease.

The tilt angle θ in the case of the truncated pyramidal crystal 10 is
As shown in FIGS. 8 and 11, a straight line r passing through the central portion n of the upper bottom surface and a central portion p of the lower bottom surface and a virtual surface G passing through the central portion p of the lower bottom surface
Is defined as an angle formed by a reference line m perpendicular to. Also in this case, the tilt angle θ is set to 0 ° ≦ θ ≦ 30 °.

FIG. 12 shows another embodiment of the present invention in which the inner surface of the oil groove 6 does not have the quadrangular pyramidal crystal 8 or the like. In this case as well, sliding characteristics similar to the above can be obtained.

FIG. 13 shows still another embodiment of the present invention, which is formed by closely adjoining both oil grooves 6.
The sliding surface forming portion 5 and the oil groove inner surface forming portion 7 each have a quadrangular pyramidal crystal 8. In this case as well, sliding characteristics similar to the above can be obtained.

Although the coating layer is formed by the electroplating method in the above-mentioned embodiment, the other coating layer forming method is P.
Examples of the formation method include a vapor phase method such as VD, ion plating, CVD, and sputtering. Further, in forming the pyramidal protrusions, it is possible to apply etching methods such as chemical etching, electric etching, vapor phase etching (bomber treatment), and mechanical processing such as transfer and cutting.

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

[0036]

According to the present invention, a sliding member having improved seizure resistance is provided by specifying the structure of the sliding surface forming portion or the oil groove inner surface forming portion as described above. You can

[Brief description of drawings]

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

FIG. 2 is a main part enlarged schematic development view showing a first example of a slide bearing half body.

FIG. 3 is a sectional view taken along line 3-3 of FIG.

FIG. 4 is a micrograph showing a crystal structure of a Pb alloy on a sliding surface.

FIG. 5 is a micrograph showing a crystal structure of a Pb alloy when a sliding surface forming portion is longitudinally cut.

FIG. 6 is a main part schematic perspective view showing a first example of a sliding surface forming part.

FIG. 7 is an X-ray diffraction diagram of a Pb alloy crystal in a sliding surface forming portion.

FIG. 8 is a main part schematic perspective view showing a second example of a sliding surface forming part.

9 is a micrograph showing a crystal structure of a Pb alloy corresponding to FIG.

FIG. 10 is an explanatory diagram showing a method for measuring a tilt angle of a quadrangular pyramidal crystal.

FIG. 11 is an explanatory diagram showing a method for measuring a tilt angle of a truncated pyramidal crystal.

FIG. 12 is a sectional view showing a second example of a sliding bearing, which corresponds to FIG.

13 is a cross-sectional view showing a third example of a sliding bearing, which corresponds to FIG.

[Explanation of symbols]

1 Sliding bearing (sliding member) 5 Sliding surface forming part 6 oil groove 7 Oil groove inner surface forming part 8 Pyramidal crystals (pyramidal protrusions) 10 Square pyramid-shaped crystals (pyramidal-shaped protrusions) a Sliding surface x Opponent member

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C25D 3/56 Z 8414-4K

Claims (2)

[Claims] 1. A sliding member having a sliding surface (a) with a mating member (x) and an oil groove (6) opening to the sliding surface (a), wherein a sliding surface forming portion ( 5) A sliding member, characterized in that it has at least one of a plurality of pyramidal protrusions (8) and a plurality of truncated pyramidal protrusions (10). 2. A sliding member having a sliding surface (a) with a mating member (x) and an oil groove (6) opening to the sliding surface (a), wherein a sliding surface forming portion ( 5) and the oil groove inner surface forming portion (7) each have a plurality of pyramidal protrusions (8).
And a sliding member having at least one of a plurality of truncated pyramidal protrusions (10).