JPS63195438A - Wet-type friction material - Google Patents

Abstract

PURPOSE:To improve the permeability of oil and to lengthen the life by using porous hollow glass as an inorganic additive of friction material obtained by forming mixed material comprising a friction condition, an inorganic additive and resin. CONSTITUTION:Mixed material comprising base material, a friction conditioner, an inorganic additive and resin is formed to manufacture wet type friction material. Porous hollow glass is used as at least a part of the inorganic additive. The porous hollow glass has a particle diameter of 10-100mum and a pore-size of 0.1-5mum, and its addition proportion by weight is 20-60 wt% per 100 wt% the whole of components except a resin component. Thus retention of oil is improved, a cooling effect and a lubricating effect produced by oil of friction material are enhanced, so that durability and heat resistance can be improved, a friction coefficient can be stabilized over a long period of time, and abrasion loss can be lowered so as to lengthen the life.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wet friction material with improved heat resistance and durability.

[Prior art] Wet friction materials conventionally used in oil include fibers, friction modifiers,
A lining material was formed by adding and mixing a phenol resin to an inorganic additive, which was then processed into a ring shape and adhered to both sides of a metal plate that was also formed into a ring shape.

For example, in Japanese Patent Application Laid-Open No. 58-7793'7, glass fibers are used in an amount of 30 to 60 parts by weight per 100 parts by weight of the total friction material.
There is a disclosure of the friction material used in parts by weight.

Further, Japanese Patent Application Laid-open No. 59-81340 discloses a friction material based on pulp fibers, to which balloon-shaped silica is added in an amount of 5 to 70 parts by weight based on the total friction weight.

[Problems to be Solved by the Invention] The above-mentioned wet friction material mainly uses diatomaceous earth, which is an additive called an inorganic additive or a friction modifier.

This diatomaceous earth is naturally produced, and its particle size ranges widely from several microns to several hundred microns. For this reason, mixing with the resin during molding tends to be incomplete, and the fixing rate during paper making is inconsistent. Furthermore, although the diatomaceous earth is porous, the effective diameter of its pores is only about 40% of the total pores. Therefore, there are limits to the oil retention, absorption, and conformability of wet friction materials in oil, and there are problems with heat resistance and durability.

An object of the present invention is to provide a wet friction material that solves the above problems by improving the permeability of oil such as inorganic additives.

[Means for Solving the Problems] The present invention provides a wet friction material obtained by molding a mixed material consisting of a base material, a friction Wt modifier, an inorganic additive, and a resin, in which at least a portion of the inorganic additive is is characterized by being a porous hollow glass.

The base material of the wet friction material of the present invention is ms! Both fibers and inorganic fibers can be used. As an organic fiber,
Link pulp, wood pulp, synthetic pulp, polyester fibers, acrylic fibers, polyamide fibers, polyvinyl alcohol-modified fibers, polyvinyl chloride fibers, polypropylene tlH1 carbon U & fibers, etc. can be used alone or in combination. As the inorganic fiber, one or more types of potassium titanate fiber, glass fiber, kaolin fiber, silica fiber, bauxite fiber, kyanite fiber, boron fiber, magnesia fiber, rock wool fiber, gold a fiber, etc. are used. be able to. Note that it is effective to use organic fiber as the main material for weight reduction.

The friction modifier is used to increase and stabilize the number of IIJ frictions, and includes, for example, metal powder such as aluminum powder, copper powder, and iron powder, rubber powder, cashew dust, and graphite powder.

The greatest feature of the present invention is the use of porous hollow glass as an inorganic additive. This porous hollow glass preferably has a particle size of 10 to 1100 t1 and a pore size of 0.1 to 5 μm. If the pore size is smaller than 0.1 μm, oil absorption properties are poor, and if it exceeds 5 μm, oil retention is poor (and undesirable).
Distribution in the range of m gives good results in terms of compatibility with oil, retention, absorption, etc.

This porous hollow glass can be easily obtained, for example, by treating hollow glass with an alkali. If the amount of this porous hollow glass is less than 20% by weight, oil absorption and oil absorption will deteriorate, and if it exceeds 60% by weight, the fixing rate will decrease, which is not preferable.

In addition to the porous hollow glass described above, conventionally used inorganic additives such as silica, talc, magnesium oxide, kaolin, barium sulfate, potassium phosphate, calcium carbonate, and siliceous earth can also be used.

The resin binds additives, and as in the past, phenol resin, epoxy resin, melamine resin, urea resin, etc. are used.

To produce the friction material of the present invention, a mixture of base fibers, a friction modifier, and an inorganic additive is made into paper in water, and the paper product is impregnated with a resin and cured, or the base material,
It can be easily manufactured by heating and press-molding a mixture consisting of a tlA modifier, an inorganic additive, and a resin in a mold.

[Operations and Effects of the Invention] The wet friction material of the present invention improves oil retention, absorption, and conformability by using porous hollow glass as at least a part of the inorganic additive. It is estimated that the cooling and lubrication effects of the oil in the material will increase. This improves durability and heat resistance, stabilizes the friction coefficient over the long term, and
It has become possible to extend the lifespan by reducing the amount of wear.

[Example] This will be explained in detail below using examples.

(Example 1) Am fiber A (cell o-li! Ift>2011% and organic 4! miscellaneous B (aromatic polyamide fiber) 30% by weight,
Friction modifier (cashew dust) 10% by weight, porous hollow glass (C-10 grade hollow glass manufactured by Nippon Sheet Glass Co., Ltd., treated with pores (alkali treatment) to have a pore size of 0.2 to 1μ
A 40 wt. The obtained paper body was impregnated with a phenol resin and hot-molded to obtain the friction material of Example 1.

(Example 2) Organic fiber A (cellulose fiber) 13.3% by weight, structured fiber B (aromatic polyamide fiber >20% by weight, friction modifier (cashew dust) 6.7% by weight, same as Example 1 A friction material was prepared in the same manner as in Example 1 from a mixture of 60 ml of porous hollow glass and used as a wet type I!! friction material in Example 2.

(Comparative Example) A friction material was prepared in the same manner as in Example 1 except that diatomaceous earth was used instead of the porous hollow glass, and a wet type I! comparison example was prepared.
It was made of J rubbing material.

(Evaluation) SAE# for each product of Example 1, Example 2, and Comparative Example
A friction test was conducted using 2 testing machines. The conditions are as follows. Lining inner diameter 108mm, outer diameter 127mm11, core metal thickness 1ffil11, friction material one side thickness 0.5mm, mating plate thickness 1,811111. Oil Dexron■, joint rotation speed 500Orpm, inertia 2゜□kg-cn
+-5ec Number of linings: 5, clutch pressing load: 1
The weight was 300 kg, the oil temperature was 100°C, and the joining cycle was 30 seconds. The test results are shown in Figure 1. Examples 1 and 2 have better friction coefficient μ and stability than the comparative example. Further, in Examples 1 and 2, the above test was conducted up to 6,000 times, but in the comparative example, the test was interrupted after 4,000 times.

When the condition of the test product at this time was observed, it was found that Example 1 had medium to large black discoloration. In the case of the porous hollow glass of Example 2 with a concentration of 60%, blackening was small, whereas in the comparative example, carbonization peeling was observed. As a result of the above, the heat resistance of the examples was improved compared to that of the comparative examples.

Fig. 2 shows a comparison of the amount of wear at this time.

Comparative example (conventional product) has a Q of 4mff1 after 4000 times, while Example 1 has a Q of 0.1311111 after 6000 times.
% In Example 2, the amount of wear was reduced to 0.111 IIl after 6000 cycles, and the durability was improved.

As a result of the above, the material to which porous hollow glass is added is a wet friction material with improved heat resistance and durability compared to conventional diatomaceous earth.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the results of measuring the dynamic friction coefficient using an SAE #2 tester, and FIG. 2 is a graph showing the amount of wear after the test. Patent applicant: Toyota Motor Corporation Agent
Patent Attorney Hirotoshi Okawa Patent Attorney Akio Maruyama Figure 1 '@' A Group Figure 2 Z

Claims (3)

[Claims] (1) A wet friction material obtained by molding a mixed material consisting of a base material, a friction modifier, an inorganic additive, and a resin, characterized in that at least a portion of the inorganic additive is porous hollow glass. Wet friction material. (2) The wet friction material according to claim 1, wherein the proportion of the porous hollow glass is 20 to 60% by weight when the entire other components excluding the resin component are 100% by weight. (3) Porous hollow glass has a particle size of 10 to 100 μm and 0
．． The wet friction material according to claim 1, having a pore diameter of 1 to 5 μm.