JP3042539B2 - Sliding material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sliding material, and more particularly to a sliding bearing, in particular, a mating shaft having a coarse roughness and / or a shaft material of cast iron. The present invention relates to a sliding material which is required to have abrasion resistance because a shaft from which a part of the matrix is likely to fall off is used as a mating material, or to have corrosion resistance to lubricating oil.

(Prior art) Bronze and lead bronze, which have been frequently used as bushing materials, are sliding materials having excellent wear resistance and load resistance. As the oil temperature rises, bearing troubles occur frequently,
In particular, the appearance of a sliding material having excellent wear resistance has been expected.

A sliding material obtained by adding a hard material to lead bronze and sintering it on a steel sheet according to such a change in use conditions is used.

The invention of Japanese Patent Publication No. 57-50844 proposed by the present applicant belongs to such a sliding material.
Pb, 1-30% of hard material, balance of Cu composition, or 10 ~
40% Pb, 1-30% hard material, 0.1-10% Sn and / or
Or a 0.1% to 5% of Sb, the composition of the balance Cu, is a hard _{material, Mo, Co, Fe 3 P} , FeB, Fe 2 B or a specific composition Ni, where the use of Co-based self-fluxing alloy .

Conventionally, Cu-based sintered alloys to which graphite or Sn and graphite are added as sliding materials used under non-lubricated or boundary lubricating conditions have been disclosed in JP-B-36-67, JP-B-39-27985, and JP-B-39-27985. Known in Japanese Patent Publication Nos. 36-13058 and 46-43681.

JP-B-46-43681, cited above, discloses Cu-Sn or Cu-Sn-Pb
As refractory material system alloy, Zr, Cr, V, Mo , Ta, metals such as _{W, Al 2 O 3, ZrO 2} , TiO 2, oxides such as ThO _2, SiC, and WC, etc., AlN, TaN, nitrides such as TiN, proposes MoB, borides such as WB, silicides such as CrSi _2, graphite, etc. wear resistance component which contains boron, a material used for applications such as a brake material .

(Problems to be Solved by the Invention) Oxides, nitrides, carbides, etc. proposed as hard materials in Japanese Patent Publication No. 46-43681 cited above improve the properties as brake materials, but are used under boundary lubrication conditions. The sliding resistance of such sliding members is insufficient. Furthermore, Zr, Cr, V, Mo, Ta, W
Metals exhibit better seizure resistance than oxides, nitrides, and carbides, but are all elements that are difficult to alloy with Cu, and are therefore familiar with the matrix even when alloyed in Cu. Poor, easy to fall off, abrasive wear due to the dropped metal particles, followed by seizure, resulting in poor seizure resistance.

In the sliding material described in JP-B-57-50844, the Pb content is 10-40%.
It has been established. Although this Pb content makes the conformability good, it has been found that the hard material falls off from the Pb phase during sliding, and there is a disadvantage that the effect of the hard material cannot be sufficiently exerted. In addition, it has been found that when the above sliding material is used particularly for an automatic transmission or the like, Pb is easily corroded by a high oil temperature lubricating oil, and there are disadvantages such as a decrease in bearing strength. Furthermore, the sliding material of Japanese Patent Publication No. 57-50844 was insufficient in friction characteristics and lubricity.

Therefore, an object of the present invention is to provide a sliding material having excellent seizure resistance, abrasion resistance, and friction characteristics, and a sliding material having excellent corrosion resistance in addition to these properties.

(Means for Solving the Problems) The present invention provides 1 to 10% by weight of graphite,
At least one of MoS ₂ and WS ₂ , 1 to 30% of at least one hard material selected from at least one of the following groups (a) to (b), and the balance substantially 0.1 to 15: % S
A sliding material composed of a Cu-based sintered alloy containing n and 1 to 10% by weight of graphite, at least one of MoS ₂ and WS ₂ and 1 to 30% At least one selected from at least one of the following groups (a) and (b), and if necessary, at least one hard material selected from the group (c), and the balance substantially A sliding material composed of a Cu-based sintered alloy containing 0.1 to 15% of Sn and 0.1 to 30% or less of Pb,
Invention.

(A) Fe ₂ P, Fe ₃ P, FeB, Fe ₃ B, Ni-based self-fluxing alloy (b) Fe-Ni, Fe-W, Fe-V, Fe-Ti, Fe-Nb, CuP (c) Co , Co-based self-fluxing alloys, Fe-Cr, Fe-Mn, Fe-Si and Fe-M
o Hereinafter, the configuration of the present invention will be described.

The present invention provides a method of improving wear resistance by adding graphite, MoS ₂ , WS _2, etc. as a means of improving frictional properties to a Cu-Sn binary alloy containing no Pb in the first invention as a means of improving corrosion resistance. The method is characterized in that a hard material is added as a means. Conventionally, Pb has been added to Cu-based bearing alloys in order to improve conformability and lubricity.However, in situations where corrosion by lubricating oil is likely to occur, Pb corrosion occurs first, followed by hard material and metal phase falling off. In some cases, the strength was reduced and the life of the bearing was exhausted. On the contrary,
The Pb-free and Cu-based bearing alloy according to the first invention is considered to be unsatisfactory in conformability, but has good corrosion resistance, and has excellent wear resistance as a result of the absence of Pb and dispersion of hard materials. The bearing alloy of the first invention exhibits excellent properties in an environment where corrosion and wear are more important than conformability as a result of these properties.

Sn in the first invention improves mechanical strength and corrosion resistance. To obtain the results, it is necessary to add 0.1% or more of Sn.
-Precipitates the intermetallic compound of Sn, deteriorating the load resistance and impact resistance of the Cu matrix. The preferred amount of Sn to be added is 3 to 10%.

As a measure to improve wear resistance, one or more hard materials (Fe ₃ P, FeB, Fe ₂ B, etc.) are added to the bronze matrix by weight%.
And add 1 to 30% and sinter. The powders of the above various hard materials are mixed with Cu-Sn powder and sintered, and the powder obtained by crushing the sintered body and graphite etc. are mixed and sintered again, and almost all the hard materials are dispersed in the particles. It is held firmly and receives a load by coming into contact with the mating material when sliding with the mating material, preventing wear of the sliding material and preventing falling off of the hard material.

The group A of the hard material is a phosphide and a self-fluxing alloy having the same characteristics as the phosphide, and a material which is well-compatible with the Cu alloy is particularly selected. That is, both the phosphide and the boride are Fe compounds that are familiar with Cu.
Therefore, Fe such as phosphide added to the sliding material is Cu
And sintering to promote sintering
It is expected that phosphides and the like are firmly retained in the Cu alloy matrix.

Group B of the hard material is ferroalloy and CuP having properties equivalent thereto. Ferroalloy Fe has good adhesion to Cu, and therefore has high adhesive strength to Cu alloy matrix.

If the addition amount of the hard material is less than 1%, it is not effective in improving the wear resistance. On the other hand, if it exceeds 30%, defects such as damaging the mating material and decreasing the sinterability of the alloy appear. A preferable addition amount of the hard material is 2 to 10%, more preferably 3 to 6%.

Graphite, MoS ₂ , and WS ₂ are additives that reduce the coefficient of friction and exhibit lubricity. These are dispersed among the Cu alloy particles in which the hard material is dispersed. It is desirable that hard materials are not dispersed as much as possible in particles such as graphite. This is because hard materials dispersed in particles such as graphite easily fall off due to weak holding power of graphite or the like. If the amount of graphite or the like is less than 1%, the effect of improving seizure resistance under boundary lubrication conditions is small. On the other hand, if it exceeds 10%, the contact ratio between copper alloy particles is reduced and Cu particles are reduced by graphite or the like. Because it is surrounded and isolated, its strength and wear resistance are reduced.

In the alloy of the second invention, in order to improve conformability and lubricity as compared with the first invention, 0.1 to 30% of Pb is added at the expense of a slight deterioration in corrosion resistance. Pb is added
If it is less than 0.1%, it does not contribute to improvement in conformability and the like, and if it exceeds 30%, the corrosion resistance is significantly reduced. A preferable addition amount of Pb is 3 to 9%.

In order to manufacture the above alloy, a metal powder such as Cu, Sn, and Pb or an alloy powder (particle size of 177 μm or less) and a hard material powder (particle size of 100 μm or less) are mixed by a V-type blender, and the mixed powder is temporarily sintered, The sintered powder is pulverized, and the obtained powder is mixed with graphite or the like (having a particle size of 100 μm or less), sprayed on a back metal steel plate, and sintered at 650 to 900 ° C. After the sintering, if a reduction is performed by a roll, a dense sintered body can be obtained.

In addition, as the copper alloy powder, the present applicant disclosed in Japanese Patent Application Laid-Open No. 63-31293.
As disclosed in No. 3, electrolytic copper powder can be used. In this case, the hard material can be dispersed in the copper alloy matrix by mixing together the copper alloy powder, the hard material powder, and graphite.

(Function) Since the hard particles added to the sliding material of the present invention are harder than the generally used sliding partner, they are less likely to be worn by the partner. This helps maintain the sliding characteristics when the surface roughness of the mating material is large. For example, assuming DCI (spheroidal graphite cast iron) or gray cast iron as a material having a large surface roughness, these materials lose their spherical or flaky graphite on the sliding surface and become rough. The part damages the sliding material and causes a tendency for the Cu particles to fall off. For this reason, in conventional sliding materials of this kind, seizure resistance rapidly deteriorates when the surface roughness of the mating material increases. However, since the hard material particles are harder than these mating materials, even if the mating material has a large surface roughness, the hard material particles are less likely to be worn away, and as a result, exhibit excellent seizure resistance to these mating materials. The hardness of DCI is about Vickers hardness (Hv) of about 200 at the time of casting, and about 400 after heat treatment of the VCI, and all of the hard materials show higher hardness.

Further, a hard material that was firmly held in the Cu alloy was selected.

Further, in the present invention, the friction coefficient of the sliding member is reduced and stabilized by using graphite, MoS ₂ , WS _{2 and the} like, so that seizure and wear are less likely to occur. If a hard material is present in the graphite particles or the like, the hard material easily falls off, and the friction coefficient immediately increases, and the performance of graphite or the like is merely reduced to the friction coefficient at the beginning of sliding. In order to avoid such a situation, in the present invention, a hard material having good compatibility with the Cu alloy is selected to prevent the hard material from sneaking into graphite or the like in the powder metallurgy process, and as a result, wear resistance and seizure resistance Is improved.

The surface of the sliding material is exposed to the lubricating oil, and if the corrosion progresses further, the Pb particles will fall off not only on the surface but also inside the sintered body due to corrosion, reducing the strength of the bearing and ending its life. I will. The mechanism of corrosion of Pb by lubricating oil is considered to be more chemical than electrochemical corrosion (because the potential of Pb and Cu is higher in the latter and lower in the former). Corrosion due to inorganic acids generated by the combustion gas of the engine mixed into the oil, corrosion due to organic acids in the lubricating oil, corrosion due to additives to the lubricating oil, and the like are conceivable. Which of these corrosive media corrodes Pb particles depends on the use of the sliding material and the operating conditions of the equipment. For example, bearings used in transmissions of automatic transmissions are most likely, and bearings around engines that are subjected to severe operation are most likely. Various additives have been used in lubricating oils, but the fact is that additives are considered without bearing in mind the wear of the bearings. There is doubt.

The present inventor studied a method of improving the chemical corrosion resistance of Pb particles by alloying Pb particles, but since all types of alloy elements tested have been alloyed into Cu particles, an alternative method To reduce the content of Pb
A method was devised in which the particles were small or not present at all. As a result, since the bearing life was increased, it was found that enhancing corrosion resistance was a prerequisite for exhibiting the above-described effects of a hard material.

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

(Example) Example 1 Bronze having a component of Cu-10% Sn was formed into a powder by a gas atomization method, and a powder having a size of 177 μm or less was used as a raw material. On the other hand, as a hard material, Fe ₃ P
Powder was prepared. Bronze powder and 5% Fe ₃ P powder were mixed in a V-type blender for about 30 minutes. This mixed powder is 10 cm in diameter,
It was placed in a graphite mold having a height of 10 cm, molded at a pressure of 1 ton / cm ² , and then temporarily sintered at 450 ° C. for 30 minutes in H ₂ gas. Thereafter, the temporary sintered body was taken out and pulverized to −100 mesh with a pulverizer. 6% of graphite powder (average particle size 20μm)
The mixture was added and mixed in a V-type blender for about 30 minutes. Thereafter, the mixed powder was degreased, sprayed 1 mm thick on a sanded 1.36 mm thick steel plate, and sintered in an H ₂ atmosphere at a temperature of 820 ° C. for 30 minutes. Subsequently, the sintered material was rolled to a thickness of 1.5 mm with a roll, and then again sintered for the second time under the same conditions to obtain a bimetal material. This material was cut into a predetermined size to obtain a test piece for a seizure and wear test.

 The conditions of the wear resistance test are shown below.

Testing conditions Testing machine: Cylindrical flat plate friction and wear testing machine Load: 10kgf Oil type: ATF oil (Automatic trans-mission fluid
Oil) Oil temperature: 100 ° C Mating shaft: S55C (quenched) Shaft rotation speed: 200 rpm Shaft roughness: 1.5 to 2 μmRz Test time: 60 min The baking test conditions are shown below.

Testing machine: Box-type bush tester Rotational speed: 4800rpm Load: 150kg Lubrication: Oil type-ATF oil, lubrication method-Dipping method Oil temperature: 20 ° C Mating shaft: SCM420 Shaft roughness: 0.8μmRz Oil clearance: 50μm Evaluation of seizure resistance The test was performed by judging the time from when oil was drained to when the bearing temperature rose to 200 ° C. when the bearing temperature was stabilized after the test was started.

For comparison, a similar test was performed for the following comparative materials.

(1) Comparative material 1 JIS-LBC3 (Cu-10% Pb, 10% Sn, lead bronze) (2) Comparative material 2 JIS-LBC6 (Cu-23% Pb, 3% Sn, lead bronze) (3) Comparison Material 3 (LBC6 lead bronze with 5% Fe ₃ P added) The results are shown in the following table.

From the results shown in this table, it is clear that the material of the present invention has excellent seizure resistance and abrasion resistance. Further, by comparing the present invention with Comparative Material 3, it is clear that the addition of graphite improves seizure resistance and abrasion resistance.

Example 2 As shown in Table 2, a bimetal material was manufactured in the same manner as in Example 1 for a mixed powder in which the compositions of Sn, Pb and a hard material were changed.

 The conditions of the wear resistance test are shown below.

Test conditions Testing machine: Cylindrical flat plate friction and wear testing machine Sliding speed: 0.42m / s Load: 10kgf Oil type: ATF oil (Automatic trans-mission fluid
Oil) Oil temperature: 120 ° C Mating shaft: S55C (quenched) Shaft roughness: 1.5-2 μmRz Test time: 60 min The wear resistance was evaluated based on the volume wear.

Abrasion test conditions Testing machine: Thrust testing machine Rotation speed: 1000rpm Load: Increased at a rate of 20kg / 10 minutes Lubrication: Oil type-ATF oil, lubrication method-Dipping method Oil temperature: 50 ° C Mating 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.

Testing machine: Static oil boiling tester Oil type: ATF oil Oil temperature: 170 ± 5 ° C Time: 200hr The test results are shown in Tables 2 and 3.

From Table 2, it is clear that the sample of the present invention has better corrosion resistance, abrasion resistance and seizure resistance than the comparative material.

Table 3 shows the results when various hard materials were used while keeping the Sn content at 10%, the Pb content at 5%, and the graphite content at 4%. Depending on the type of the hard material, the seizure resistance varies between the minimum value and the maximum value in a range of about twice, but it can be seen that in any case, it is superior to the comparative material.

(Effects of the Invention) As described above, the sliding material according to the present invention has an environment in which the mating shaft has a large roughness and is likely to be worn, an environment in which corrosion due to lubricating oil is likely to occur, or an environment in which wear and corrosion simultaneously progress. Demonstrates excellent performance when used in

Continuation of front page (56) References JP-A-56-169739 (JP, A) JP-A-2-107773 (JP, A) JP-A-55-164049 (JP, A) JP-A-53-146902 (JP) , A) JP-A-55-122842 (JP, A) JP-A-4-17635 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C22C 9/00-9/10

Claims (4)

(57) [Claims] 1 to 10% by weight of graphite,
At least one MoS ₂ and WS _2, and at least one hard material selected from 1% to 30% below (a) ~ (b) at least one group of group, the balance being substantially 0.1 ~ 1
A sliding material comprising a Cu-based sintered alloy containing 5% Sn. (A) Fe ₂ P, Fe ₃ P, FeB, Fe ₃ B, Ni self-fluxing alloy (b) Fe-Ni, Fe-W, Fe-V, Fe-Ti, Fe-Nb, CuP 2. A sliding material according to claim 1, wherein said sliding material comprises Co, a Co-based self-fluxing alloy, Fe-Cr, Fe-Mn, Fe-Si and Fe-Mo.
Further comprising at least one member of the group, and wherein the Fe ₂ P, Fe ₃
Group (a) consisting of P, FeB, Fe ₃ B, Ni-based self-fluxing alloy and F
A sliding material comprising e-Ni, Fe-W, Fe-V, Fe-Ti, Fe-Nb, and CuP, wherein the total amount of the group (b) and the group (c) is 1 to 30%. 3. 1% to 10% by weight of graphite,
At least one MoS ₂ and WS _2, and at least one hard material selected from 1% to 30% below (a) ~ (b) at least one group of group, the balance being substantially 0.1 ~ 1
A sliding material comprising a Cu-based sintered alloy containing 5% of Sn and 0.1 to 30% of Pb. (A) Fe ₂ P, Fe ₃ P, FeB, Fe ₃ B, Ni self-fluxing alloy (b) Fe-Ni, Fe-W, Fe-V, Fe-Ti, Fe-Nb, CuP 4. A sliding material according to claim 3, wherein the sliding material comprises Co, a Co-based self-fluxing alloy, Fe-Cr, Fe-Mn, Fe-Si and Fe-Mo.
Further comprising at least one member of the group, and wherein the Fe ₂ P, Fe ₃
Group (a) consisting of P, FeB, Fe ₃ B, Ni-based self-fluxing alloy and F
A sliding material comprising e-Ni, Fe-W, Fe-V, Fe-Ti, Fe-Nb, and CuP, wherein the total amount of the group (b) and the group (c) is 1 to 30%.