JPS616420A - Connecting rod - Google Patents

Abstract

PURPOSE:To obtain a connecting rod which is light and has a bearing function instead of a connecting rod bearing by providing a large end portion bearing surface formed by a Cu-Pb base alloys flame spraying layer and a Pb-based alloys overlay layer. CONSTITUTION:A 25-03-1.0-0.1-residue Pb-Sn-Ni-Fe-Cu alloy is flame sprayed to a connecting rod main body portion 1 of a connecting rod manufactured by using S55 as base material and a bearing surface 8 of a connecting rod cap 4 by Meteco Corp.'s plasma flame spraying device to form a flame spraying layer (9)200mum thick, which is machined to be 150mum thick. After that, an overlay layer 10 of 9-2-residue Sn-Cn-Pb alloy is formed by a fused plating method. If a nickel plating intermediate layer is disposed between the flame spraying layer 9 and the overlay layer 10, plating for the overlay layer 10 is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to reducing the weight of a connecting rod for a reciprocating engine.

[Prior art]

Reciprocating engine connecting rods (hereinafter referred to as connecting rods) are manufactured as forged products with a recess in the center to ensure strength, but as the speed of engines increases, the connecting rods (hereinafter referred to as connecting rods) are manufactured as forged products with a recess in the center. In order to suppress the increase in inertial force as much as possible, reducing the weight of the connecting rod has become an urgent issue.

Nia 70 Sodo Vi As shown in Figure 3, it consists of a connecting rod body 1, a large end part 2, and a small end part 3, and the large end part 2 is divided into two parts, and a bearing hole 5 is formed by the core body 1 and the connecting rod cap 4. are doing. Conventionally, the big end 2 is roughly knurled to the crankshaft via a split type connecting rod bearing 6, and in the case of a 70-ring type connecting rod in which the piston pin and the small end 5 can slide, the small end It was assembled into the piston pinot via the copper-based bimetallic bushing 7 that was press-fitted into the section 3. Therefore, when the piston reciprocates, the piston pin and the small end 3
It has a structure in which it slides between the bushing 7 fixed to the crankshaft and the connecting rod bearing 6 of the big end 2.

The above-mentioned connecting rod bearing 6 may be made of low carbon steel with a thickness of 1.5 to 2-5 mm as a backing metal, and an At-8n or At-Pb alloy foil with a thickness of about 200 mm, or with the above-mentioned alloy powder. was sintered to form a two-layer structure, and a thin layer of lead-based alloy was then plated on top to improve bearing performance.

In this way, the connecting rod bearing 6 is attached to the large end 2 of the connecting rod, and the copper bushing is press-fitted to the small end 3, so that the connecting rod as a whole has a large outer diameter. is making it heavier. Also, to make the connecting rod lighter, simply connect the connecting rod bear link 6.
If the bushing 7 is abolished, the bearing hole 5 will seize up and the problem will not be solved.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention aims to provide a lightweight connecting rod that has a bearing function in place of a conventional connecting rod bearing.

[Structure of the invention]

In the present invention, even if the connecting rod bearing at the big end is abolished, the bearing surface is made of Cu, which is more suitable for heavy-duty engines and has better plating properties than At-8n or At-Pb alloys.
- It has been found that a conorod having the same bearing performance as a conventional one can be obtained by thermally spraying a Pb-based alloy and then overlaying a Pb-based alloy to improve conformability.

However, the bearing surface at the small end must be exposed to particularly high temperatures (300°C).
It is preferable to use a conventional bushing when a flame resistance strength of Kd is required.

That is, the connecting rod of the present invention has two layers: a sprayed layer of a copper-lead alloy and an overlay layer of a lead-based alloy on the bearing surfaces of the connecting rod body bearing and the connecting rod cap bearing that form the connecting rod body. It is characterized by forming a bearing layer.

Regarding the components of the copper-lead alloy, as the amount of Pb increases, the seizure resistance improves, but when the content exceeds 34, the wear resistance deteriorates and the strength also decreases. If it is less than 20%, the seizure resistance will not improve. Note that even if Sn, Ni', -re, etc. are mixed in as impurities during thermal spraying, there is no problem as long as the amount is 4% or less.

The Pb-8n alloy used for the overlay layer is important for bearing plating, and contains approximately 6 to 10 inches of Sn, but also contains Cu or In.
n-Cu, Pb-8n-In alloys can also be used.

If the total thickness of the thermal sprayed layer and overlay layer is less than 20 pm, the wear life will be insufficient, but if it becomes too thick, the weight reduction effect will decrease and the processing cost will increase, so the thermal sprayed layer should be 1.
50 to 200 μm, preferably Viio to 22-5p as overlay layer.

In this way, even if the overlay layer partially disappears due to wear, the Co--Pb layer can maintain seizure resistance and wear resistance.

〔Example〕

Examples will be described below with reference to the drawings.

25% Pb-α 3% 5n-1,0 Ni-
An alloy consisting of 0.1% Fe and the remainder Cu was bath-sprayed using Metco's plasma spraying equipment to form a sprayed layer 9 with a thickness of 200 pm, which was machined to a thickness of 150 pm, and then hot-dip plated. An overlay layer 10 consisting of 9% 5n-2% C and the remainder Pb was formed. Figure 2 is A in Figure 1.
- represents an enlarged sectional view in the A direction. Note that if an intermediate layer of nickel plating is provided between the thermal spray layer 9 and the overlay I@10, the overlay layer can be easily plated.

Connect the above connecting rod to a 4-cylinder 4-cycle gasoline engine (cylinder bore diameter 83rrrm, stroke 85mm).
, displacement 18+9cc), rotation speed 5.60O
As a result of continuous testing for 300 hours under full load of r, p, m, no seizure, cracking, or wear was observed on the sliding surfaces, and there was no change in friction performance compared to conventional connecting rods.

〔Effect of the invention〕

As explained above, the weight of the connecting rod of the present invention is reduced by 60 to 50 g by eliminating the connecting rod bearing.
As a result, the inertial force exerted on the crankshaft is reduced, which contributes to reducing the diameter of the crankshaft and, in turn, reducing the weight of the vehicle body.

Furthermore, since the connecting rod of the present invention has a bearing layer formed directly on the base material, it has good thermal conductivity and there is no temperature rise in the bearing part. Even if the overlay layer is partially worn out, the thermally sprayed copper-lead alloy layer maintains seizure resistance and wear resistance, making it suitable for heavy-load, high-speed engines.

Additionally, the elimination of connecting rod bearings simplifies the work on the bearings, improving productivity.

[Brief explanation of the drawing]

FIG. 1 shows a plan view of a connecting rod according to the present invention, FIG. 2 shows a cross-sectional view taken in the AA direction in FIG. 1, and FIG. 3 shows a plan view of a conventional connecting rod. In the figure,

Claims (4)

[Claims] (1) A bearing with two layers: a sprayed layer of copper-lead alloy and an overlay layer of lead-based alloy on the bearing surfaces of the conrod main body bearing and conrod cap bearing that form the conrod bearing hole. A connecting rod characterized by forming layers. (2) The connecting rod according to claim 1, wherein the sprayed layer is made of a copper-lead alloy consisting of 20 to 34% lead and the balance copper. (3) The connecting rod according to claim 1, wherein the overlay layer is made of an alloy of lead-tin, lead-tin-copper, or lead-tin-indium. (4) The sprayed layer is made of a copper-lead alloy consisting of 20 to 34% lead and the balance copper, and the overlay layer is lead-tin or lead-tin.
A connecting rod according to claim 1, which is made of an alloy of copper or lead-tin-indium.