JPH07139554A - Bearing device of internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent wear of the partner material generated by fretting between a bearing and a partner material made of light metal. CONSTITUTION:A coating layer containing carbon and/or fluororesin of 10-50 weight % and rubber as the essential rest part, and having the film thickness of 5-20mum, is provided on the outer circumference of the back metal of a bearing or the inner face of the large end part 15 of a connecting rod 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device for an internal combustion engine. More specifically, for example, in a connecting rod bearing, a bearing device or a main device capable of reducing fretting wear of a light metal connecting rod. The present invention relates to a bearing device that can reduce fretting wear of a housing using aluminum for weight reduction of the bearing.

[0002]

2. Description of the Related Art Conventionally, it has been proposed to insert a hard rubber between a bearing metal and a bearing housing from the viewpoint of reducing engine noise (Japanese Utility Model Publication No. 60-22020), and from the viewpoint of vibration isolation, bearings. It has also been proposed to place synthetic rubber or the like between the housing and the housing.
No. 3-146840, Japanese Utility Model Laid-Open No. 57-71812).

Recently, in order to reduce the weight of an engine, weight reduction of moving parts constituting the engine has been promoted. As one of them, the connecting rod is mainly made of various aluminum (alloy) or various light metals such as titanium (alloy). It is considered to be configured as. On the other hand, in order to rotatably fit the connecting rod and the crankshaft, the bearing interposed between them is mainly a back metal such as a semi-circular mild steel plate and a bearing alloy such as an aluminum alloy or kelmet formed on it. I am trying. Although the fretting wear will be mainly described below with reference to the example of the connecting rod, the fretting wear also occurs in other internal combustion engine parts in the same situation.

In the case of a light alloy connecting rod, a minute collision or a minute slip occurs between the large end of the connecting rod and the back surface of the bearing under the high load or high rotation operating condition of the engine. Fretting wear is likely to occur, and light metals such as aluminum, which is softer than steel, may eventually cause damage to the connecting rod due to scratches, seizure, or adhesion.

As a countermeasure against this, JP-A-4-282013 proposes to form an epoxy resin coating containing MoS 2 on either the inner surface of the large end of the connecting rod or the outer surface of the bearing metal.

[0006]

In the case of a resin coating containing MoS2, a large amount of MoS2 powder particles fall off from the resin base material due to micro-slip or micro-tapping that occurs on the inner surface of the large end of the connecting rod and the back surface of the bearing. To accelerate the peeling of the film.

Therefore, the present invention provides a bearing device for an internal combustion engine which can significantly reduce the fretting wear of the rubber coating and thereby prevent the fretting of a light metal mating member which is in sliding contact with the back metal of the bearing. To aim.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a rubber containing 10 to 50% by weight of carbon or a fluororesin on the housing side surface of a bearing or the bearing side surface of the housing whose back metal is a soft steel plate provided in the housing. 5 to 20 layers
The present invention relates to a bearing device for an internal combustion engine, which is provided with a thickness of μm.

In the present invention, various rubbers such as fluororubber, nitrile rubber, hydrogenated nitrile rubber and epichlorohydrin rubber can be used as the rubber. The preferred rubber type in the present invention is fluororubber,
More preferably, it is a vinylidene fluoride copolymer, and its characteristics are as follows. Tensile strength: 5-15 MPa Hardness: IRHD 65-80 Elongation: 150-300%

As a result of studying various additives for improving the fretting wear resistance of rubber, particularly the sliding wear property, the present inventor has found that carbon and fluororesin have the effect of reducing peeling of the rubber coating. I found it. Carbon is preferably carbon black or the like, and fluororesin may be PTFE, FEP, ETFA or the like. If the addition amount of these is less than 10% by weight, there is no effect. On the other hand, if it exceeds 50% by weight, abradable wear due to carbon falling off from the coating is likely to occur, or hitting wear is likely to occur due to too much fluorine resin. Therefore, the amount of carbon and fluororesin added is 10
It should be in the range of ˜50% by weight. The preferable addition amount is 20 to 40% by weight. The preferred particle size of the fluororesin is 5 μm or less.

The coating layer according to the present invention is formed by coating rubber with carbon and / or fluororesin together with a solvent or dispersant to a predetermined thickness by spray coating, screen printing, pad printing, dipping printing, brush coating, etc. By evaporating the solvent by drying at ~ 80 ° C and then vulcanizing at 130-200 ° C,
It is firmly adhered to the inner surface of the back metal of the bearing or the large end of the connecting rod. That is, by integrating the rubber with the back metal by the above method, the anti-fretting property can be sufficiently exhibited by utilizing the vibration absorbing property peculiar to the rubber by the carbon / fluorine resin-added rubber. Solvents include butyl acetate, acetate, isoamyl acetate,
Acetic ester type such as ethyl glycol acetate,
Alternatively, ketones such as MEK (methyl ethyl ketone), MIBK (methyl isobutyl ketone), cyclohexanone, and isophorone can be used. Instead of the above organic solvent, water-dispersed rubber can be used for forming the coating.

The coating of the present invention has a thickness of 5 μm.
If it is less than m, there is no effect of preventing fretting wear, and the clearance with the mating member becomes large, so that the mating member is easily hit and peeled off. If the thickness of the coating exceeds 20 μm, when the bearing coated with the coating is installed in the engine, peeling easily occurs,
Since the amount of deformation becomes large, the desired clearance design method cannot be obtained after assembly. Therefore, the thickness of the coating needs to be 5 to 20 μm. The preferred film thickness is 5 to 10 μm.

FIG. 2 shows the fretting of the conventional material obtained by adding 50% by weight of MoS2 to the epoxy resin and the material of the present invention obtained by adding 50% by weight and 30% by weight of carbon black to the fluororubber under the conditions of the embodiment described below. It is a graph which shows the result of having measured the peeling area of a coating by performing an abrasion test. It is clear from the graph of coating peeling area ratio-repeat number shown in FIG. 2 that carbon black reduces the peeling area of the fluororubber coating. Hereinafter, the present invention will be described in more detail with reference to examples.

[0014]

1 is a perspective view of a piston and a connecting rod, in which a piston 11 and a small end 13 of an aluminum-based light alloy connecting rod 12 are connected by a piston pin. The large end portion 15 of the connecting rod 12 is divided into two, and is fixed with bolts and nuts after a crankshaft (not shown) is sandwiched between the divided large end portions. Reference numeral 21 is a main bearing, and 22 is a crank washer.

Between the large end portion 15 of the connecting rod 12 and the crankshaft, a semi-circular bearing 16 is installed, which is pressed against a steel alloy backing of JIS SPCC standard on the outer periphery of a bearing alloy such as aluminum alloy. , Rotates following the former rotation. The coating layer may be formed on the inner surface of the large end portion 15 or only on the inner surface.

A coating material was prepared by mixing various rubber materials shown in FIG. 3, a diamine-based vulcanizing agent and butyl acetate. As the coating layer, an aluminum layer, an Al—Sn bearing alloy layer and a Sn overlay are formed on the surface of the back metal, or a Cu—Pb alloy and Pb—Sn.
An -In overlay was prepared separately, washed with trichlene for 5 minutes, and then preheated in a constant temperature bath at 80 ° C for 15 minutes. A premixed coating material was formed into a film having a thickness of 5 to 10 μm on the surface of the preheated back metal by the following method. Spray coating method: Nozzle diameter 1.3 mm, air pressure 2.5
kg / cm2 Screen printing method: Using polyester screen After that, baking was performed at 150 ° C for 30 minutes.

As the fretting wear test, a reciprocating load test under the following conditions was performed. Test conditions Rotational speed: 50 Hz (3000 rpm) Load: -15 N to 35 kNt Oil temperature: 150 ° C. Repeat number: 10 7 times

As shown in the table of FIG. 3, the peeling area is large when the coating layer is PAI resin with carbon added or rubber alone. On the other hand, it is clear that the rubber-carbon or fluororesin-based material of the present invention is effective against fretting wear in the examples of the present invention because the peeling area is extremely small.

[0019]

As described above, according to the bearing device of the present invention, since the coating peeling area is small in the reciprocating load test for reproducing the operation of the internal combustion engine, the bearing can be used for a long time when used in the internal combustion engine. It is clear that it is possible to prevent direct contact between the backing metal and the mating material made of light metal. Therefore, fretting wear of the light metal mating member can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of a piston and a connecting rod.

FIG. 2 is a graph showing the relationship between the number of repetitions and the coating peeling area.

FIG. 3 is a table showing film thicknesses and peeled areas of various coating layers.

[Explanation of symbols]

 11 Piston 12 Connecting Rod 13 Small End 15 Large End 16 Bearing

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[Procedure amendment]

[Submission date] June 8, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

FIG. 3 is a table showing the film thickness and the peeled area of various coating layers.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masaharu Kikuchi 3-65 Midorigaoka, Toyota-shi, Aichi Otoyo Kogyo Co., Ltd. (72) Inventor Keiichi Shimazaki 3-65, Midorigaoka, Toyota-shi, Aichi Otoyo Kogyo Co., Ltd. (72) Inventor Hirofumi Michioka 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Yoshio Fuwa, 1 Toyota Town, Toyota City, Aichi Toyota Motor Co., Ltd.

Claims (1)

[Claims] 1. A rubber layer having a thickness of 5 to 20 μm containing 10 to 50% by weight of carbon or fluororesin on the housing side surface of the bearing or the housing side surface of the housing whose back metal is made of a mild steel plate provided in the housing. A bearing device for an internal combustion engine, characterized in that