JPS61221399A - Plate bearing - Google Patents

Abstract

PURPOSE:To improve the corrosion and wear resistances of a plate bearing by forming an overlaid layer consisting of Pb, Sn, and Cu in a specified ratio on the surface of a substrate. CONSTITUTION:A Cu or Al alloy layer 2 and a plated Ni layer 3 are successively formed on a backing strip 1 to obtain the substrate of a plate bearing for an internal-combustion engine. An overlaid layer 4 consisting of 15-30% Sn, 1.0-5.0% Cu and the balance essentially Pb is formed on the substrate. The layer 4 may further contain 0.1-5% Sb. The layer 4 has improved corrosion and wear resistances because of the increased Sn content. Sb improves the fatigue resistance.

Description

[Detailed Description of the Invention] <Object of the Invention> Industrial Field of Application The present invention relates to plain bearings, and more specifically, due to the rise in temperature of lubricating oil due to the increase in output of internal combustion engines in recent years and the oxidation of lubricating oil at high temperatures, etc. This invention relates to a plain bearing that exhibits sufficient performance under conditions such as an increase in the amount of organic acids generated.

Conventional technology Conventionally, the bearing metal used in internal combustion engines has a half-shaped or cylindrical steel backing metal, and a multi-layered copper-based or aluminum-based bearing base metal. These copper-lead bearing alloys, bronze bearing alloys, aluminum bearing alloys, etc. developed as high-load bearings have excellent load-bearing properties, but they have other characteristics required for bearing base metals, such as seizure resistance and embedding resistance. There are problems with embeddability, conformability, etc., and in order to solve this problem, it is necessary to overlay a metal with embeddability and conformability on the bearing base metal. For example, in conventional automotive bearings, a three-layered copper or aluminum alloy is adhered as an intermediate layer on a backing metal by a method such as sintering, casting, or pressure bonding, and then an overlay layer with a thickness of 10 to 30 μm is applied on top of this. bearings are used. This overlay layer has the effect of improving the bearing's wear resistance, conformability, and foreign matter embedding ability. Conventionally, the composition of the overlay has been Pb-3n series, Pb-3n-3b series, Pb-3n-C
U-based systems, Pb-3n-In systems, etc. are known, and in particular, 85% to 95% lead disclosed in U.S. Pat. No. 2,605,149.
, a pb-sn-cu based overlay containing 8-12% tin and 2-3% copper is most commonly used. The lead in this overlay improves the compatibility between the bearing and the journal and the embedding of foreign matter in the lubricating oil, the tin improves corrosion resistance, and the copper plays a role in improving fatigue resistance.

However, in recent years, as the output of internal combustion engines has increased and the temperature of the lubricating oil has increased, the fangs and valleys have become softer and their wear resistance has deteriorated.Furthermore, high temperatures have accelerated the oxidation of the lubricating oil. These improvements were made because of the problem of corrosive products such as organic acids forming and corroding the overlay. t-valley development is required.

Problems to be Solved by the Invention The present invention aims to solve these problems, and specifically improves corrosion resistance and wear resistance by increasing the tin content of the conventional Pb-3n-1u overlay. improve the
Another object of the present invention is to provide an overlay with improved fatigue resistance by adding antimony thereto.

<Structure of the Invention> Means for Solving the Problems and Their Effects The present invention provides a flat bearing for use in an internal combustion engine that contains 15 to 30% tin and 1.0 to 5.0% copper on the surface of its base. It is characterized by forming an overlay layer, the remainder of which is essentially lead, or an overlay layer further containing 0.1 to 5.0% antimony.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIGS. 1(a) and 1(b) are a perspective view and a sectional view taken along arrow A-A, showing an example of a plain bearing of the present invention.

In FIG. 1, reference numeral 1 indicates a backing metal, 2 a copper or aluminum alloy layer, 3 a nickel plating area, and 4 an overlay layer.

The tin in the conventional A-valley becomes a solid solution with lead, and some exist as a matrix and some exist as a copper-tin intermetallic compound in this matrix, and the remaining tin is It forms fine tin crystals and is scattered throughout the matrix. During operation of the internal combustion engine, this copper-tin intermetallic compound combines with the tin solidly dissolved in the fine tin crystals or matrix, and gradually transforms into a copper-tin intermetallic compound with a high tin content. . As a result, the amount of solid solution tin in the 7 trix and tin interspersed in the 7 trix decreases, reducing the corrosion and abrasion resistance of the overlay.

Furthermore, the tin in the overlay that is present near the nickel plating layer forms an intermetallic compound with the nickel and gradually migrates to the nickel metal. In this case as well, as with the copper-tin intermetallic compound described above, the tin content gradually shifts to a tin-nickel intermetallic compound with a higher tin content during operation of the internal combustion engine, so the tin content in the overlay near the nickel plating layer increases. The wear resistance and corrosion resistance in this area are greatly reduced.

Based on the observation of the behavior of tin as described above, the present invention increases the tin content in the overlay to 15 to 30%, and further adds antimony to 0.1 to 5.0%. This solves the problems of wear resistance and corrosion resistance, and further improves fatigue resistance.

Next, to explain the role and addition amount of each element in the overlay of the present invention, tin improves the corrosion resistance and wear resistance of lead. If it is less than 15%, the tin particles scattered in the 7 trix will be reduced for the reasons mentioned above, and the corrosion resistance and wear resistance of the overlay will be greatly reduced. Furthermore, the tin content is 3
If it exceeds 0%, fatigue resistance and conformability will deteriorate.

Therefore, the optimal tin content is 15 to 30%.

Furthermore, when antimony is added to a conventional overlay, it combines with the tin in the overlay, and as an intermetallic compound interspersed with fine crystals in the lead-tin matrix, this compound is hard and improves the wear resistance of the overlay. However, its content is between 01 and 5. Q96 is optimal; anything higher than that will make it less compatible with Japur.

In addition, copper is added to improve the fatigue resistance of the overlay, but the best performance is achieved when the content is around 1.0% to 5.0%, and fatigue resistance decreases outside this range. .

Example This will be further explained below using examples.

Example 1 First, a bearing alloy is degreased and pickled in the same manner as in general electroplating, and then nickel plated to a thickness of 1.0 to 2.0 μm. In the case of a copper-based bearing alloy, the role of this nickel plating is to prevent tin in the A-valley from diffusing into the intermediate copper alloy during operation of an internal combustion engine, thereby preventing the corrosion resistance of the overlay from deteriorating. This nickel plating is then electroplated with the following bath composition (AJ plating bath and current density).

) /-Copper (as metallic copper) 1-4 Borofluoride hydrogen acid 40-50 (1/ Lusorcin
1.0-5.0 Tsunopyratin
0.1~Q, 5rr current density 1.0~3.
The plain bearing after OA/dm2 has four elements: backing metal, bearing alloy, nickel, and new overlay, and the composition of the new overlay is as follows.

Example 2 The bearing base metal was plated with nickel in the same manner as in Example 1, and the following bath composition (Bl
Electroplating is carried out at a current density of

The composition of the overlay after plating at a current density of 1.0-3 and OA/dm2 is as follows.

As described above, the antimony in this new overlay combines with tin to form a tin-antimony total interstitial compound, which maintains the hardness of the overlay when soaked in 51i and improves wear resistance. In order to improve the conformability and embeddability of this new overlay, these properties can be further improved by softening annealing at a temperature of 100 to 150° C. for about 2 hours after plating.

As explained in detail above, in order to measure the corrosion resistance of the new overlay, 1% oleic acid was added as a corrosive agent to 5AE10 engine oil containing no inhibitor, and 121
The corrosion reduction was measured after immersion at ℃ for 50 hours. As a result, the corrosion resistance of the new overlay was approximately five times that of the conventional overlay.

Furthermore, in order to measure the wear resistance of the new Valley, the load was 5 GOklJ/CI2 and the number of revolutions was 3 in the Underwood test bench.
50 rpm, overlay thickness 0.020 mm, @receiving surface temperature 175°C1 lubricating oil SAE 201-40, test time 100 hours, and weight loss of the bearing before and after the test was measured. As a result, the weight reduction of the new overlay was about one-fifth of that of the conventional overlay. This is clearly judged to be the effect of the addition of tin and the addition of antimony.

(Effects of the invention) As explained in detail above, by increasing the tin content of the conventional overlay and further adding antimony, corrosion resistance, wear resistance, and fatigue strength have been greatly improved, and A new A-valley plain bearing has been obtained that can sufficiently cope with increased output, increased lubricating oil temperature, and increased organic acids generated by oxidation of lubricating oil at high temperatures.

The fatigue resistance of the conventional overlay plating based on Pb-3n-Tn containing about 10% indium was tested under the same conditions as the wear resistance test described above. We conducted a comparative test with the product of the present invention until fatigue failure occurred in the overlay on a machine, and as a result, both products were within the durability time of 140 to 160 hours, indicating that the components of the present invention have fatigue resistance. It could be confirmed.

The new overlay of the mouth was Pb-Sn- in the same plating bath.
It is possible to perform four-component alloy plating of Cu-Sb, which eliminates the need for multiple plating baths unlike indium-containing overlays, and saves labor in the plating process. There is no need for post-plating heat treatment. Furthermore, each alloying element is generally easily available and has many advantages, such as being inexpensive.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are a perspective view and a sectional view taken along arrow A-A, showing an example of the flat bearing of the present invention. Code 1... Back metal 2... Copper or aluminum alloy layer 3...
...Nickel plating layer 4...Overlay film Patent applicant KonuDC Co., Ltd. Agent Patent attorney Yoshikatsu Matsushita Deputy Attorney Fumiaki Shima

Claims (1)

[Claims] 1) Tin 15 is added to the surface of the base of a plain bearing used in an internal combustion engine.
30% and 1.0 to 5.0% copper, with the remainder being substantially lead. 2) Tin 15 is added to the surface of the base of plain bearings used in internal combustion engines.
~30%, copper 1.0-5.0% and antimony 0.1
5.0%, with the remainder being substantially lead.