JP2505632B2 - Sliding material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sliding material, and more specifically to a sliding bearing, and more particularly to a sliding material for a sliding bearing which is required to have corrosion resistance against lubricating oil. It is a thing.

(Prior Art) Bronze and lead bronze, which have been widely used as bush materials, are sliding materials with excellent wear resistance and load resistance, but recent changes in the operating conditions of bearings, especially high surface pressure, With the increase in oil temperature and the like, wear problems of bearings have frequently occurred, and it has been expected that a sliding material having particularly excellent wear resistance will appear.

Conventionally, Cu-based sintered alloys to which graphite has been added as a sliding material used under unlubricated or boundary lubrication conditions, or Sn and graphite have been added are Japanese Patent Publication Nos. 36-67 and 39-27985, Japanese Patent Publication No. 36-13058, Japanese Patent Publication No. 46-4368
It is known from publication No. 1 and the like.

(Problems to be Solved by the Invention) In a Cu—Sn alloy, the Cu matrix is strengthened by Sn, but the strengthening is insufficient depending on the use conditions. Specifically, the holding power of the graphite of the Cu matrix is weak and the graphite falls off during processing or when sliding
As the Cu flows and covers the graphite, the lubricity of graphite cannot be exerted during sliding,
Wear resistance and seizure resistance are insufficient. Above-mentioned Japanese Patent Publication Sho 46-
Zr, Cr, V, Mo, Ta, W proposed as a hard material in 43681 publication
All such metals are elements that are difficult to form alloys with Cu, and therefore, even if alloyed in Cu, they are not well compatible with the matrix, so they easily fall off, and abrasive wear due to the dropped metal particles occurs. The seizure resistance is inadequate because of seizure and subsequent seizure. Furthermore, since Cu matrix cannot be expected to be strengthened by solid solution such as Zr,
Little improvement in graphite holding power.

Therefore, an object of the present invention is to provide a sliding material having excellent seizure resistance, wear resistance, corrosion resistance and frictional characteristics.

(Means for Solving the Problems) The present invention is based on the total weight percentage of 0.1 to 10% S.
i, 0.1 to 30% of at least one of Mn and Zn, and 0.1 to 15
% Copper, the balance being a copper alloy consisting essentially of Cu,
1-10% graphite, MoS ₂ and at least 1 of WS ₂
The first invention is a sliding material obtained by spraying seeds and a back metal on a backing metal, and the weight percentage of the whole is 0.1 to 10% of Si, 0.1
-30% of at least one of Mn and Zn, 0.1-15% of Sn,
And a copper alloy containing 0.1 to less than 10% Pb, the balance being substantially Cu, and 1 to 10% graphite, MoS ₂ and WS.
_{A second} invention is a sliding material in which at least one kind of ₂ is sprinkled on a backing metal and sintered.

The configuration of the present invention will be described below. The present invention is a Cu containing no Pb in the first invention as a means for improving corrosion resistance.
-Sn binary alloy is added with graphite, MoS ₂ and WS ₂ (hereinafter also referred to as "graphite etc.") as a means for improving frictional properties, and holds graphite etc.
As a means for strengthening the holding power of the Cu matrix, Si is contained, and at least one of Mn and Zn is added.

Conventionally, in Cu-based bearing alloys, Pb was added to improve the conformability and lubricity, but in the situation where corrosion due to lubricating oil is likely to occur, Pb corrosion first occurs, followed by the loss of hard materials and metal phases. Occasionally, the strength was reduced and the life of the bearing was sometimes exhausted. On the other hand, the Pb-free and Cu-based bearing alloy according to the first aspect of the invention is considered unsatisfactory in terms of compatibility, but has good corrosion resistance, and as a result of the absence of Pb and dispersion of hard materials, wear resistance is extremely excellent. In addition, due to the presence of graphite and the like, the friction properties and lubricity are good, and as a result, they exhibit superior properties in an environment where corrosion, wear and friction properties are more important than familiarity.

Sn in the first invention improves mechanical strength and corrosion resistance. In order to obtain that effect, it is necessary to add 0.1% or more of Sn, and if added in excess of 15%, brittle Cu
Precipitates an intermetallic compound of -Sn to deteriorate the load resistance and impact resistance of the Cu matrix. The preferable addition amount of Sn is 3 to 10%.

As a measure to improve the holding power of graphite etc., 0.1-10% Si is added to a bronze matrix and sintered. Si
Is well compatible with Cu and solid-solution strengthens in Cu, and Si exceeding the solid-solution limit precipitates as an intermetallic compound having a high bonding strength with the matrix and precipitation strengthens, so that the strength and hardness of the Cu matrix are enhanced.

On the other hand, when 0.1% to 30% by weight of Mn or Zn is added and sintered at 0.1 to 30%, these elements form a solid solution with Cu and enhance the strength of the Cu matrix. Therefore, graphite etc.
As it is firmly held by the Cu alloy particles, the falling and chipping of graphite during sliding is reduced. Furthermore, the Cu matrix is less likely to flow during sliding, and is less likely to be fogged on the graphite surface, so that the performance of graphite can be exhibited without impairing it. Si, Mn, Zn, etc. are alloyed with Cu or added as a single element to react with Cu during sintering. Graphite, MoS ₂ and WS ₂ are additive substances that reduce the coefficient of friction and exhibit lubricity. These are dispersed between Cu alloy particles, and the bonding strength at which these particles are bonded plays an important role in retaining graphite. If the amount of graphite, etc. is less than 1%, the effect of improving seizure resistance under boundary lubrication conditions is small, while if it exceeds 10%, the proportion of copper alloy particles contacting each other is small and Cu particles are also formed by graphite etc. Since it is surrounded and isolated, sintering does not proceed sufficiently and strength and wear resistance are reduced.

The alloy of the second invention is added with 0.1 to 10% Pb at the expense of some deterioration in corrosion resistance in order to improve the conformability and lubricity as compared with the first invention. The amount of Pb added is
If it is less than 0.1%, it does not contribute to the improvement of the familiarity, and if it exceeds 10%, the corrosion resistance is significantly reduced. The preferable amount of Pb added is 3 to 9%.

In order to produce the above alloy, Cu, Sn, Pb, Si and other alloy powders (particle size 177 μm or less) are mixed with a V-type blender
The mixed powder is pre-sintered, the sintered powder is crushed, graphite and the like (particle size of 100 μm or less) are mixed with the obtained powder, and the mixture is sprayed on the backing steel plate and sintered at 650 to 900 ° C. A dense sintered body can be obtained by rolling with a roll after sintering.

As for the copper alloy powder, the applicant of the present invention disclosed in Japanese Patent Laid-Open No. 63-3129
Electrolytic copper powder can be used as disclosed in No. 33. In this case, the copper alloy powder, hard material powder, graphite and the like can be mixed together to disperse the hard material in the copper alloy matrix.

(Function) In the present invention, graphite, MoS ₂ , WS _{2 and the} like are strengthened in the Cu matrix to prevent the flow of the Cu matrix during sliding, so that the performance of graphite and the like can be fully exhibited. As a result, by lowering and stabilizing the coefficient of friction of the sliding member, seizure and wear are prevented.

Fig. 1 shows Cu alloy (-200 mesh) having a composition of Cu-8.5% Sn-2% Si-1% Mn-0.5% Fe from 92% by weight and graphite (-200 mesh) from 8% by weight. The mixed material of the present invention was sintered at 850 to 900 ° C. for 5 to 30 minutes, and the sliding material of the present invention was manufactured by using Cu-8.5% Sn-0.5 as a comparative material.
9% Cu alloy (-200 mesh) with a composition of% Fe
The results of a seizure test of a sliding material produced by sintering a mixed powder of 2% by weight and 8% by weight of graphite (−200 mesh) at 850 to 900 ° C. for 5 to 30 minutes are shown. The horizontal axis is the slip distance, and the vertical axis is the wear depth. It is clear from the figure that the sliding material of the present invention exhibits excellent seizure resistance.

The surface of the sliding material is exposed to lubricating oil, and if corrosion progresses further, Pb particles will fall off not only on the surface but also inside the sintered body due to corrosion, and the strength of the bearing will decrease and the life will end. I will end up. It is considered that the corrosion mechanism of Pb by the lubricating oil is more chemical than the electrochemical corrosion (because the potential of Pb and Cu is noble in the latter and base in the former), and the corrosive medium is the lubricating oil. Corrosion due to inorganic acids generated by engine combustion gas mixed in the engine, corrosion due to organic acids in the lubricating oil, corrosion due to additives to the lubricating oil, etc. are considered. Which of these corrosive media corrodes the Pb particles depends on the application of the sliding material and the operating conditions of the equipment. For example, it is most likely in bearings used in automatic transmission transmissions, and most likely in bearings around the engine, which are subject to harsh operation. Various additives to lubricating oil are used, but it is the fact that additives are considered without considering the wear of bearings, so unexpected corrosion occurs due to additives. There is also doubt.

The present inventor investigated a method of improving the chemical corrosion resistance of Pb particles by alloying Pb particles, but since all kinds of alloying elements tested were alloyed with Cu particles, a method alternative to this As the Pb content is reduced,
A method has been devised in which the amount of particles is small or not present at all. As a result, since the bearing life was extended, it was found that increasing the corrosion resistance is a prerequisite for exerting the above effect of the hard material.

 Hereinafter, the present invention will be described in more detail with reference to examples.

(Example) Example 1 Sn, Pb, Si, Zn and M showing the addition amount to the alloy in Table 1
Atomized powder of copper alloy containing n, graphite (Gr), M
The raw materials to which oS ₂ and WS ₂ (average particle size 20 μm) were added in the amounts shown in the table with respect to the total were mixed in a V-type blender for about 30 minutes. Then, this mixed powder is degreased and sprayed on a sanded steel plate with a thickness of 1.36 mm for a thickness of 1 mm, and H ₂
Sintered for 30 minutes in atmosphere. Subsequently, the sintered material was rolled by a roll to a thickness of 1.5 mm, and then again sintered under the same conditions to obtain a bimetal material. This material was cut into a predetermined size to obtain a test piece for seizure and abrasion test.

 The conditions of the abrasion resistance test are shown below.

Test conditions Tester: Cylindrical flat plate friction and wear tester Slip speed: 0.42m / s Load: 10kgf Oil type: ATF oil (Automatic transmission fluid)
Oil) Oil temperature: 100 ° C Opposite shaft: S55C (quenched) Shaft roughness: 0.8 μm Rz Test time: 60 min The wear resistance was evaluated by the volume wear amount.

Baking test conditions Tester: Thrust tester Rotational speed: 1000 rpm Load: 10kg / 10min increase Lubrication: Oil type-ATF oil, Lubrication method-Dubzuke method Oil temperature: 80 ° C Opposite shaft: S55C Shaft roughness: 3μmRz Seizure load unit: 10 kgm Seizure resistance was evaluated by the load at the time of seizure.

The corrosion resistance test conditions are as follows.

Tester: Static oil boiling tester Oil type: ATF oil Oil temperature: 170 ± 5 ° C Time: 200hr Table 1 shows the test results.

It is clear from Table 1 that the samples of the present invention are superior in corrosion resistance, wear resistance and seizure resistance to the comparative materials.

(Effects of the Invention) As described above, the sliding material according to the present invention has an environment in which the load due to the mating shaft is large and the flow of the Cu matrix is likely to occur, an environment in which corrosion due to the lubricating oil is likely to occur, or the flow and the corrosion simultaneously proceed. Excellent performance when used in an environment

[Brief description of drawings]

 FIG. 1 is a graph showing the results of the baking test.

Claims (2)

(57) [Claims] 1. By weight percentage, 0.1-10% Si, 0.1-30%
At least one of Mn and Zn, and a copper alloy powder containing 0.1 to 15% Sn and the balance substantially consisting of Cu, and at least one of graphite, MoS ₂ and WS ₂ , Is 90 to 99% and at least one of graphite, MoS ₂ and WS ₂ is sprinkled on the backing metal in a proportion of 10 to 1% of the balance and sintered, and the sliding material is characterized. 2. By weight percentage, 0.1-10% Si, 0.1-30%
At least one of Mn and Zn, 0.1 to 15% of Sn and 0.1 to
Copper alloy powder containing less than 10% Pb and the balance being substantially Cu, and at least one of graphite, MoS ₂ and WS ₂ .
Seed and copper alloy powder is 90 to 99% and at least one of graphite, MoS ₂ and WS ₂ is spread on the backing metal in a proportion of 10 to 1% of the balance, and is sintered. Characteristic sliding material.