JPS6234262B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sliding material, and more particularly, to a sliding material having excellent friction properties, wear resistance, and load resistance.

An example of an application that normally requires excellent friction, wear resistance, and load resistance is automobile shock absorber bushings, but the sliding materials used in such reciprocating sliding mechanisms are generally Unlike sliding materials such as bearings used in machine tools, which are subject to rotation only in one direction, they tend to cause uneven contact and are prone to uneven wear due to sliding in the reciprocating direction around the uneven contact area. Therefore, the sliding material applied to the reciprocating sliding part is required to have even better load resistance and wear resistance than sliding materials used in general machine tools. Furthermore, when the sliding material has a two-layer structure, the adhesion strength between the sliding surface material and the base material is also an important condition.

Conventionally, sliding materials used in reciprocating sliding mechanisms such as automobile shock absorbers include:
Copper-lead alloys were used, but with the increase in engine power and high speed rotation in recent years, high loads and
When used under harsh conditions such as high rotation, the oil film often breaks in areas where sliding parts make uneven contact (when used in oil), resulting in a state of boundary lubrication, which increases frictional resistance considerably. This has led to the problem that smooth sliding is difficult to achieve and the amount of wear increases. It goes without saying that if a sliding material is used during dry operation, the frictional resistance will further increase and the above-mentioned tendency will be exacerbated. Therefore, in some cases, sliding materials are used in which the sliding surface material is plastic, which is generally said to have low frictional resistance even when dry. Conventionally, this sliding surface material has been made of a mixture containing tetrafluoroethylene resin as the main component and silicon added thereto, or a mixture containing tetrafluoroethylene resin as the main component with aluminum oxide, zinc and/or lead. A mixture having a composition in which each of these is added has been proposed.

However, the former has the disadvantage of increasing costs because it contains silicon in its composition, and the silicon is expensive.Also, the latter has the disadvantage that aluminum oxide has a value of around 2000 Hv and is extremely hard, so the sliding mating surface A defect was observed in that it was easy to wear out.

The present invention was made in view of the above circumstances, and its purpose is to provide excellent load resistance and wear resistance, less risk of abrasion of the sliding mating surface, and reduction in manufacturing costs. Our goal is to provide sliding materials that can.

The present invention has confirmed through experiments that silica has excellent wear resistance similar to aluminum oxide, and that amorphous silica in particular exhibits outstanding wear resistance effects that are superior to others. At the same time, confirm that it is not hard,
Moreover, the price of silica is lower than that of simple silicon.
This was done by focusing on the fact that it is 1/2 to 1/3.

The first invention is a sliding material comprising 1 to 15% by weight of amorphous silica and 1 to 50% by weight of a component consisting of at least one of zinc and lead, with the remainder being fluororesin.

The second invention contains 1 to 50% by weight of a component consisting of at least one of zinc and lead, and 1 to 15% of a combined component of amorphous silica and aluminum oxide.
It is a sliding material in which the balance is made up of fluororesin.

The third invention contains 1 to 15% by weight of amorphous silica,
1 component consisting of at least one of zinc and lead
~50% by weight and 1 to 5% by weight of a component consisting of at least one of molybdenum sulfide and graphite.
This is a sliding material in which the remaining part is made of fluororesin.

The fourth invention is 1 to 50% by weight of a component consisting of at least one of zinc and lead, and 1 to 15% by weight of a combined component of amorphous silica and aluminum oxide.
The sliding material contains 1 to 5% by weight of at least one of molybdenum sulfide, graphite, and molybdenum sulfide, and the remainder is a fluororesin.

First, in the first invention, the reason why the sliding surface material of the sliding material is made of fluororesin as the main component is that it has a characteristic of extremely low frictional resistance even during drying. If the composition ratio of the fluororesin in the sliding surface material is too small, the frictional resistance will increase, and if it is too large, the frictional resistance will increase. Examples of this fluororesin include tetrafluoroethylene resin,
Trifluorochloroethylene resin, tetrafluoroethylene
Propylene hexafluoride copolymer, vinylidene fluoride/isobutene octafluoride copolymer, or CM
-1 etc. are used, but tetrafluoroethylene resin is more preferred.

In addition, in the present invention, since a mixture of amorphous silica and a component consisting of at least one of zinc and lead is added to the fluororesin that is the main component of the sliding surface material, this sliding material In this case, the wear resistance of amorphous silica is effective, and the durability of this material can be extended. In particular, when amorphous silica is used, compared to crystalline silica, it is less likely to be fractured at fine and sharp angles, so there is a risk of damaging the soft mating surface or causing fracture. This is because the effect as an additive is not diminished by doing so. Therefore, by using amorphous silica, stable friction and wear characteristics can be obtained. As mentioned above, it goes without saying that the term "amorphous silica" as used herein includes not only completely amorphous silica but also amorphous silica with low non-crystallinity. In addition, the addition of zinc and lead improves the conformability, which is a sliding characteristic, and also improves the load bearing capacity, which is especially important for reciprocating mechanisms such as piston movements that are subjected to fluctuating lateral loads. It is possible to ensure sufficient strength to withstand exercise. The slightly harder zinc is particularly suitable for reciprocating mechanisms, while the slightly softer lead is particularly suited for rotary mechanisms.

Here, the composition range of amorphous silica is 1% by weight.
The reason for this is that if it is less than this, the effect of adding it will not be observed, and the reason why it is not more than 15% by weight is because if it is more than this, there is a risk of abrasion of the sliding mating surface. In addition, the reason why the composition range of zinc and lead is set at 1% by weight or more is that below this value, the effect of adding it is not recognized, and the reason why the composition range of zinc and lead is set at 50% by weight or less is that if it exceeds this, frictional resistance increases and the amount of heat generated increases. This is because it becomes large and easily wears out.
A more desirable range is 1 to 25% by weight.

The second invention further includes aluminum oxide and amorphous silica in an amount of 1 to 15% by weight in addition to the first invention.
It is a sliding material that is added so as to have the following properties. Even when a mixture of amorphous silica and aluminum oxide is added in this manner, the wear resistance of the sliding material can be improved and its durability can be extended, similarly to the sliding material according to the first invention. The limitation on the total weight of amorphous silica and aluminum oxide at this time is based on the same reason as mentioned above.

A third invention is a sliding material in which 1 to 5% by weight of a component consisting of at least one of molybdenum sulfide and graphite is added to the sliding material according to the first invention. According to this invention, it is possible to obtain the effect of further improving the lipophilicity and reducing the frictional resistance in addition to the sliding properties of the first invention. This is particularly effective when applied to reversible sliding mechanisms. Here, graphite includes graphite fibers, and molybdenum disulfide is preferable as molybdenum sulfide. Here, the reason why the composition range of these components is set at 1% by weight or more is that the effect of addition is not recognized below this range, and the reason why the composition range is set at 5% or less is that if it exceeds this range, wear increases and the sliding material deteriorates. This is because it reduces durability. Note that molybdenum disulfide is preferable as molybdenum sulfide.

A fourth invention is a sliding material according to the third invention in which aluminum oxide is combined with amorphous silica to form a
The sliding material was made by adding 15% by weight. Thereby, the sliding characteristics of the third invention can be maintained. The first limitation on the total weight of amorphous silica and aluminum oxide is
~For the same reason as in the third invention.

Further, in each of the above inventions, as the base material of the sliding material, a steel plate, which is widely used as a bearing material, is used, or when a porous layer is sintered and formed on the base material, the sintered metal powder is used. Copper alloys such as copper-tin, copper-lead, or copper-lead-tin powders, or iron powders or mixtures of iron, copper, and tin powders can be used as the substrate, and these powders are heated on the substrate. Sintered.

Therefore, each of the above-mentioned additives to the fluororesin, which is the main component of the sliding surface material of the sliding material, is mixed with an aqueous dispersion of the fluororesin to form a paste, and the paste is applied, for example, to the porous surface. Impregnated. The presence of this porous layer prevents the sliding surface material from peeling off from the base material, making it possible to construct a solid sliding surface.

〔Example〕

A sintered porous layer with a thickness of 0.1 to 0.2 mm is formed on a base material by heating -80 mesh to +150 mesh lead-bronze alloy powder at 780° C. in a reducing atmosphere. In the first invention, a mixture of aqueous dispersion of tetrafluoroethylene resin mixed with amorphous silica, zinc, and lead powder is coated on the porous layer, dried at about 100°C, and then reduced under pressure. Samples 1 to 10 were obtained by impregnating the resin with a temperature of 380 to 400°C, which is the softening point of tetrafluoroethylene resin. These samples were prepared using a substrate 1 as shown in FIG.
A mixture coating 3 is formed on the sintered porous layer 2 of the surface, and the thickness of the coating 3 (above the porous layer) is
0.02-0.03mm, the sliding material has silica, zinc and lead evenly distributed. Sample 35~ shown in Figure 2
Reference numeral 38 is a comparative material, which was obtained by the same method as above using a mixture having the composition shown in FIG.

〔test〕

A ring-shaped bushing was manufactured using the material obtained by the above method, and peeling and wear experiments were conducted on the sliding surface material.

Test conditions Test equipment Absorber dynamic load durability tester Variable load 0±100Kg (10.6Hz) Sliding speed Max2.0m/sec (10.6Hz) Stroke ±30mm Lubricating oil ATF (JWS 2042) Oil amount 270c.c. Judgment criteria Copper matrix It is determined that there is exfoliation wear when it is completely exposed, and the maximum number of repetitions without exfoliation wear is measured.

The test results described above are shown in FIG. As can be understood from the figure, the product of the present invention can achieve better results than the comparative material if the amount of wear with respect to the number of repetitions, the state of the lining part, and the state of wear of the mating shaft are comprehensively considered.

Similar to the first invention, the second invention includes amorphous silica in the aqueous dispersion serving as the sliding material.
Zinc, lead, and aluminum oxide are each
Samples 11 to 18 were prepared by mixing the proportions shown in the figure, and the third invention was prepared by mixing molybdenum disulfide and graphite with the first invention in the proportions shown in Fig. 2. In the fourth invention, samples 27 to 34 were prepared by further adding aluminum oxide to the third invention in the proportion shown in FIG. 2, and the same tests as described above were conducted on each of these samples. I did this. The results are shown in the results column of FIG.

It can be seen that in relation to the comparative materials, all of these examples according to the invention have a small amount of wear and are able to prevent wear of the mating shaft, and have excellent properties as a sliding material.

As explained above, the first to fourth inventions have a fluororesin as a main component, to which amorphous silica or a mixture of this and aluminum oxide is added, or zinc and/or lead. , molybdenum sulfide, and/or graphite, and all of these inventions have extremely excellent wear resistance and peeling resistance against reciprocating sliding or reversible rotational sliding under fluctuating lateral loads. In both inventions, amorphous silica is used as an additive to improve wear resistance, so even if the sliding surface is soft, there is no risk of damaging it, and there is no risk of crushing it. This does not reduce its effectiveness as an additive. Therefore, stable friction and wear characteristics can be obtained.

Furthermore, the sliding materials according to each of these inventions are of course effective for unidirectional sliding members such as bearings used in general machine tools, etc., and in this case, molybdenum sulfide or graphite is added to the composition. is added, the lipophilicity increases and the performance of the sliding surface can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of an example of a sliding material according to the present invention, and FIG. 2 is a diagram showing the compositions of the present invention product and a comparative material as well as test results for them. 1: Base material, 2: Porous layer, 3: Mixture coating.

Claims (1)

[Scope of Claims] 1 1 to 15% by weight of amorphous silica, and zinc,
A sliding material characterized in that a component consisting of at least one of lead is 1 to 50% by weight, and the remainder is a fluorine resin. 2 The component consisting of at least one of zinc and lead is 1 to 50% by weight, the combined component of amorphous silica and aluminum oxide is 1 to 15% by weight, and the remainder is composed of fluororesin. Characteristic sliding material. 3 1 to 15% by weight of amorphous silica and 1 to 50% by weight of a component consisting of at least one of zinc and lead.
A sliding material comprising 1 to 5% by weight of at least one of molybdenum sulfide and graphite, and the remainder being a fluorine resin. 4 1 to 50% by weight of a component consisting of at least one of zinc and lead, 1 to 15% by weight of a combined component of amorphous silica and aluminum oxide, and a component consisting of at least one of molybdenum sulfide and graphite. A sliding material characterized in that the content is 1 to 5% by weight, and the remainder is made of fluororesin.