JPH03215694A - Sliding member - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Industrial Application Field The present invention provides a sliding member, particularly a P
The present invention relates to a sliding member having a surface layer made of b-alloy.

(2) Conventional technology Conventionally, in this type of sliding member, the surface layer was made of Pb-Sn.
Planar bearings made of alloys are known (Japanese Patent Application Laid-open No. 5
6-96088).

(3) Problems to be solved by the invention This type of flat bearing is commonly used in the journal part of the crankshaft, the large end part of the stove, etc. in engines, but now that engines are becoming faster and more powerful. Under these circumstances, conventional plane bearings have a problem in that their surface layer has poor seizure resistance. This is due to the crystal form of the pb-sn alloy constituting the surface layer, in which crystal planes are randomly oriented.

In view of the above, an object of the present invention is to provide the above-mentioned sliding member in which the seizure resistance of the surface layer is improved by specifying the crystal form of the PB alloy.

B. Structure of the Invention (11 Means for Solving the Problems) The present invention provides a sliding member having a surface layer made of a Pb alloy on the sliding surface side with a mating member, in which the crystal form of the Pb alloy is determined by Miller index. The structure is characterized in that the orientation index in the (h00) plane is 50 to 100%.

(2) Effect Setting the orientation index in the (h00) plane as described above improves the seizure resistance of the surface layer. However, if the orientation index is less than 50%, satisfactory seizure resistance cannot be obtained.

? 3) Example 1. In FIG. 2, a plane bearing l as a sliding member is attached to a journal portion of a crankshaft in an engine.
It is applied to the large end of a connecting rod, etc., and consists of first and second halves 1,', and 1. Both halves 1, 1■ have the same structure, and include a backing metal 2, a lining layer 3 formed on the sliding surface side of the backing metal 2 with the mating member, and a lining layer 3 formed on the surface of the lining layer 3. A surface layer 4 is provided. A copper plating layer is provided between the backing metal 2 and the lining layer 3, and a nickel plating barrier layer is provided between the lining layer 3 and the surface layer 4, as required.

The back metal 2 is made of a rolled steel plate, and its thickness is equal to that of the plane bearing 1.
Determined by the set thickness. The lining layer 3 is made of copper, copper-based alloy, aluminum, aluminum-based alloy, etc., and has a thickness of 50 to 500 μm, usually 300 μm.
That's about it. The surface layer 4 is made 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 80 to 90% of P.
b and 3 to 20% by weight of Sn, and optionally C.
Contains 10% by weight or less of at least one selected from u, InSAg. Cu has the function of improving the hardness of the surface layer 4, but when its content exceeds 10% by weight,
If the hardness becomes too high, the amount of wear on the mating member will increase. C
When u is added, the hardness Hmv of the surface layer 4 is 17~
It is desirable to adjust the content so that it is 20. In and Ag have the function of softening the surface layer 4 and improving the initial break-in characteristics, but when their content exceeds 10% by weight, the strength of the surface layer 4 decreases.When adding In and Ag It is desirable to adjust the content so that the hardness Hmv of the surface layer 4 is 12 to 15.

The surface layer 4 is formed by electroplating, and the plating solution is 40 to 180 g/j! pb”, 1.
5-35g/I! ．． Sn”, 1 5 g if necessary
A borofluoride plating solution containing Cu" of 71 or less is used. The temperature of the plating solution is set at 10 to 35°C, and the cathode current density is set at 2 to 15 A/dm". FIG. 3 is an electron micrograph (10.000x magnification) showing the metal structure on the sliding surface 4a of the surface layer 4. This surface layer 4 contains P containing 8% by weight of Sn and 2% by weight of Cu.
Made of b alloy. The surface layer 4 was formed on the copper alloy lining layer 3, and the cathode current density in the electroplating process when forming the surface layer 4 was set to IOA/dm''.

The Pb alloy crystals on the sliding surface 4a form a quadrangular pyramid,
The four slopes belong to planes parallel to the (11■) plane with Miller indices.

FIG. 4 is an X-ray diffraction diagram of the PB alloy, in which only the diffraction peaks of the (200) plane and (400) plane are observed in Miller index.

Here, the orientation index O is used as an index expressing the conformality of the crystal plane.
e, Σ IhM! (However, hkf is the Miller index, Ihkjl! is the integrated intensity of the (hkf) plane, and Σhkl is I
If defined as (total sum of hkffi), the closer the orientation index Oe is to 100% in a certain (hkf) plane, the more crystal planes are oriented in the direction orthogonal to the (hkf) plane.

Table I shows the integrated strength 1hkffi and orientation index Oe in the (200) plane and (400) plane of the PB alloy.

Table 1 From Table 1, the orientation index Oe in the (h00) plane of the Pb alloy is 100%. Therefore, the Pb alloy has crystal planes oriented in each axis direction in the crystal axes a, b, and c, that is, (
h00) surface.

FIG. 5 is an electron micrograph (10,000 times magnification) showing the metal structure of the sliding surface of the conventional surface layer. This surface layer consists of Pb containing 8% by weight of Sn and 2% by weight of Cu.
It is made of an alloy, and the surface layer is formed on a copper alloy lining layer by electroplating, and is commonly used for the journal part of engine crankshafts.

FIG. 6 is an X-ray diffraction diagram of a conventional Pb alloy.

This figure does not show any orientation toward a specific crystal plane.

The integrated intensity 1hkf and the orientation index Oe in various (hkf) planes are shown in Table 2.

Table 1 As is clear from FIG. 5 and Table 2, the crystal morphology of the conventional Pb alloy is such that the crystal planes are randomly oriented.

Table (2) compares the composition of the surface layer, crystal orientation, and thus the orientation index Oe, etc. of various planar bearings.

The present invention (■) corresponds to the Pb alloy (Fig. 3) in the present invention. The present inventions (■) and (2) have lower cathode current density than the present invention (I), and accordingly, the orientation index O in the (h00) plane
e is decreasing.

In the present invention (2), the surface layer is formed from a Pb-Sn-In alloy, and the orientation index Oe in the (h00) plane is 100.
%.

The present inventions V and (2) have lower cathode current density compared to the present invention (2), and accordingly, the orientation index Oe in the (h00) plane
is decreasing. Comparative example (■) corresponds to the Pb alloy (Fig. 5) in the conventional example, but its cathode current density is unknown. Comparative Example (2) has the same composition as Inventions (1) to (2) of the present invention, but its cathode current density is unknown. FIG. 7 shows the results of the burn-in test for the present inventions I to (2) and comparative examples (2) and (2). The seizure test was carried out by sliding each plane bearing against the rotating shaft and gradually increasing the load applied to the plane bearing. Figure 7 shows the surface layer of each plane bearing when seizure occurred. The pressure was determined.

The test conditions are as follows. Rotating shaft material JIS
S48C material with nitriding treatment, rotation speed of rotating shaft
6000rp+*, oil supply temperature 120°C, oil supply pressure 3 kg/c1M, applied load 1 kg/sec *
As is clear from FIG. 7, inventions 1 to 1 and 2 to 2
has superior seizure resistance compared to comparative examples ■ and ■. This is due to the crystal morphology of the Pb alloy in the surface layer. That is, in Inventions I to ■, the crystal morphology of the Pb alloy is such that the orientation index Oe in the (hoe) plane is 50% or more, but in Comparative Examples ■ and ■, the crystal morphology of the Pb alloy is random. This is because it has an oriented crystal plane. In order to improve the seizure resistance of the surface layer 4, the orientation index Oe in the (h00) plane should be set to 5 as described above.
It is set to 0 to 100%, preferably 60% or more. In particular, when seizure resistance is required under severe conditions, the orientation index Oe in the (h00) plane is set to 97% or more. Note that the present invention is applicable not only to plane bearings but also to other sliding members.

C. Effects of the Invention According to the present invention, by specifying the crystal form of the Pb alloy constituting the surface layer as described above, it is possible to provide a sliding member in which the seizure resistance of the surface layer is improved.

[Brief explanation of drawings]

Figures 1 and 2 show a plane bearing, Figure 1 is an exploded plan view,
Figure 2 is a cross-sectional view taken along line 1 in Figure 1, Figure 3 is a micrograph showing the metal structure of the surface layer according to the present invention, and Figure 4 is an X-ray of the PB alloy constituting the surface layer according to the present invention. Diffraction diagram, Figure 5 is a micrograph showing the metal structure of the surface layer according to the conventional example, Figure 6 is
The figure is an X-ray diffraction diagram of a pb alloy constituting a surface layer according to a conventional example, and FIG. 7 is a graph showing the results of a seizure test. 1...Flat bearing, 4...Surface layer

Claims (2)

[Claims] (1) In a sliding member provided with a surface layer made of a Pb alloy on the sliding surface side with a mating member, the crystal form of the Pb alloy has an orientation index of 50 in the (h00) plane according to the Miller index.
100%. (2) No. (1) in which the orientation index is set to 60% or more
Sliding member described in section.