JPH07280008A - Wet type friction material - Google Patents

Abstract

PURPOSE:To improve a coefficient of dynamic friction and a braking ratio by controlling the quantity of Metsuke (weight of fabric per unit area) of a friction material base member in a wet type friction material and the porosity and the pore diameter of a finally completed friction material. CONSTITUTION:A friction material base member 10 of three-layer structure comprising a nonwoven fabric layer 12, a woven fabric layer 14 and a nonwoven fabric layer 16 is filled with a friction adjustment agent 18 and impregnated with a thermosetting resin and cured to obtain a wet type friction material. The quantity of Metsuke of the friction material base member 10 and the porosity and the pore diameter of a finally completed friction material can be controlled by making it into three-layer structure and changing the ratio of nonwoven fabric to woven fabric to obtain a friction material which has a high dynamic friction coefficient, an excellent braking ratio and an excellent peel strength between friction material layers even under the condition of a heavy load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a wet clutch or a lockup clutch in an automatic transmission for a vehicle, a synchronizer ring in a manual transmission, a wet multi-plate clutch for a motorcycle, a wet clutch or a wet brake for an industrial construction vehicle. Wet friction material.

[0002]

2. Description of the Related Art A so-called paper friction material having paper as a base material is mainly used as a wet friction material. Paper friction materials are manufactured by mixing various friction modifiers and the like into pulp, making paper, and further impregnating and curing a binding resin such as a phenol resin. This paper friction material has a high dynamic friction coefficient and a good static-dynamic ratio (ratio between final dynamic friction coefficient μo and dynamic friction coefficient μd).

[0003]

However, the paper friction material is liable to cause delamination (so-called peeling) under the condition that the load on the wet friction material is increased due to the increase in engine output of the vehicle these days, and the friction of the friction material is reduced. It has become difficult to maintain the delamination strength, and it is no longer possible to cope with an increase in load. Wet friction materials such as sintered alloys, semi-metallic and elastomer-based materials have been proposed as improvements, but they have the drawbacks of low dynamic friction coefficient and poor static-dynamic ratio, and still reach a satisfactory level. I can't find anything.

On the other hand, as a friction material using a woven cloth or a non-woven cloth as a base material, JP-A-59-140929, JP-A-2-36392 and JP-A-5-39392
-78648 and JP-A-5138790 are known. Woven and non-woven fabrics are suitable materials for obtaining the strength of the friction material. However, the friction material using woven cloth has a drawback that the coefficient of dynamic friction is low when used in automatic transmission fluid. In the friction material using a non-woven fabric, when the thickness of the final finished friction material required as a product is 0.6 mm or more, it is difficult to control the basis weight of the base material, and the porosity of the final finished friction material is
Since it is difficult to control the pore diameter, it is difficult to increase the dynamic friction coefficient and reduce the amount of wear.
Therefore, it is strongly desired to develop a wet friction material that can cope with an increase in load without causing delamination and has a high dynamic friction coefficient and a good static-dynamic ratio.

Therefore, as a result of intensive studies to improve the above-mentioned drawbacks, the present inventors combined a non-woven fabric and a woven fabric to control the basis weight of the friction material base material, and to improve the porosity and the porosity of the finally completed friction material. It has been found that by controlling the pore diameter, a wet friction material having a high dynamic friction coefficient and a good static-dynamic ratio and capable of sufficiently responding to an increase in load can be obtained.

[0006]

The present invention comprises a three-layer structure in which a woven fabric is interposed between dry nonwoven fabrics, the surface of which is filled with a friction modifier, and the entire three layers are impregnated with a thermosetting resin. The above-mentioned problems were solved by a wet friction material obtained by compression-molding the friction material base material.

The porosity is 25 to 70%, and it is desirable that 75% or more of all the pores have a pore diameter of 5 to 100 μm.

[0008]

The friction material base material of the present invention is obtained by three-dimensionally intertwining a dry non-woven fabric and a woven fabric. By having a three-layer structure, it has excellent three-dimensional entanglement strength. Further, by interposing the woven cloth, it becomes easy to control the basis weight of the friction material base material, the porosity and the pore diameter of the finally completed friction material. Therefore, the delamination phenomenon of the final finished wet friction material can be prevented,
It is possible to obtain a friction material that can be used for a long time even under high load conditions. In addition, by setting the porosity and pore diameter of the friction material produced by filling the surface of the base material with the friction modifier and then impregnating and curing the thermosetting resin and performing heat compression molding, a high dynamic friction coefficient can be obtained. A good static / dynamic ratio can be obtained.

As the dry non-woven fabric in the present invention, fibers such as para-aramid fiber, meta-aramid fiber, carbon fiber, glass fiber, acrylic oxide fiber, quinol fiber, silica fiber, alumina fiber, silica-alumina fiber and cellulose fiber may be used alone or 2 A mixture of three or more kinds is used, which is three-dimensionally entangled by a non-woven fabric manufacturing method such as needle punching or spunlace.

The woven fabric in the present invention includes para-aramid fiber, meta-aramid fiber, carbon fiber, glass fiber, acrylic oxide fiber, quinol fiber, silica fiber,
Fibers such as alumina fibers and silica / alumina fibers are used alone or in combination of two or more.

The friction material base material is produced by three-dimensionally intertwining the dry non-woven fabric and the woven fabric.

As the friction modifier in the present invention, diatomaceous earth, graphite, activated carbon, molybdenum disulfide, inorganic powdery substances such as silica powder, cashew dust, fluororesin powder, organic powder such as spherical phenolic resin cured product powder are used. Substances. At the time of filling the base material, these may be used alone or in combination of two or more kinds, and the filling amount is preferably 10 to 100 g / (square meter). Further, the friction modifier is mixed with a thermosetting emulsion resin such as an epoxy resin before being filled in the friction material base material. The mixing ratio of the friction modifier at this time is preferably 20 to 80% by weight.

Examples of the thermosetting resin used in the present invention include phenol resin, modified phenol resin modified with oil, rubber, epoxy resin and the like, melamine resin, epoxy resin, polyimide resin, unsaturated polyester resin and the like. These can be used alone or in combination of two or more kinds of resins. Among them, phenol resin and modified phenol resin are preferable. The impregnation amount of the thermosetting resin is preferably 3 to 30% by weight based on the intermediate product in which the friction modifier is completely filled with the friction modifier.

In the wet friction material of the present invention, a friction modifier is dispersed in a thermosetting emulsion resin by using a roll coater or the like on the surface of a three-layer structure product in which a woven fabric is interposed between dry nonwoven fabrics. The composition is filled with the composition, dried, impregnated and cured with a thermosetting resin, and compression molded. After that, the friction material is processed into an appropriate shape such as a ring shape, and is bonded to the core plate using a phenol resin adhesive or the like.

The porosity and pore diameter in the present invention were determined by the following methods.

The final completed wet friction material adhered to the core plate was cut into a size of about 3 cm in length and about 1 cm in width together with the core plate and mounted on a mercury press-in type pore size measuring device (manufactured by PMI Co., USA) to obtain mercury. The pore size distribution was measured from the intrusion pressure and amount. The final completed wet friction material was subjected to an oil impregnation treatment together with the core plate in a commercially available automatic transmission oil (DEX type), and the porosity was calculated from the oil content, the friction material volume, and the automatic transmission oil specific gravity. The wet friction material of the present invention has a porosity of 25 to
70%, and 75% or more of the total number of pores is 5 to 100 μm
It is easily manufactured by adjusting the dry non-woven fabric areal weight, the woven fabric areal weight, the friction modifier filling amount, the thermosetting resin impregnation amount, and the like so that the above distribution is obtained.

The porosity range is 25 to 70%. When the porosity is 25% or less, the dynamic friction coefficient decreases and the static-dynamic ratio deteriorates. When the porosity is 70% or more, the amount of wear increases significantly. Also, regarding the pore size, 75% of the total number of pores
The above is 5 to 100 μm. If the pore diameter is 5 μm or less and 25% or more of the total number of pores is used, the dynamic friction coefficient is lowered and the static-dynamic ratio is deteriorated. If the pore diameter is 100 μm or more and the pore number is 25% or more of the total number of pores, the wear amount is significantly increased and the dynamic friction coefficient is lowered.

[0018]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 Para-aramid fiber (fiber length 51 mm, fiber diameter 12 μm)
The dry-type nonwoven fabric weight is 450 g / (square meter)
Was three-dimensionally entangled using a needle punching machine. Next, a woven meta-aramid fabric (100 g / (square meter)) was overlaid on the entangled sheet, and further para-aramid fiber (fiber length 51 mm, fiber diameter 12
(μm) to be laminated at 150 g / (square meter),
A substrate was produced by three-dimensionally entangled with a needle punching machine. As shown in FIG. 1, the friction material base material 10 includes a nonwoven fabric layer 12, a woven fabric layer 14, and a nonwoven fabric 16.

Next, diatomaceous earth 30% by weight, activated carbon 30
50 g / (square meter) (a friction modifier amount of 30 g / (square meter)) is filled on the surface of the base material by using a roll coater, and the composition obtained by stirring and mixing with a mixer at a ratio of 40 wt% by weight and 40% by weight of epoxy emulsion resin is filled. 1 at 150 ° C
It was dried for 0 minutes. In FIG. 1, reference numeral 18 is a filling layer of the friction modifier.

Next, the whole intermediate product was impregnated with a commercially available phenol resin so as to be 10% by weight based on the intermediate product, and cured at 220 ° C. for 10 minutes. Furthermore, FIG.
As shown in, from the sheet-shaped intermediate product 20,
Using press and mold, outer diameter 133mm, inner diameter 113m
The ring-shaped product 22 of m was punched out. An adhesive is applied to both surfaces of a separately prepared ring-shaped core iron plate (not shown), and 60
It dried at 20 degreeC for 20 minutes. A ring-shaped product 22 is attached to both surfaces of the ring-shaped iron core plate coated with this adhesive so that the layer 18 of the friction modifier is on the surface, and the surface pressure is 200 kg / (square centimeter) at 250 ° C. for 3 minutes. Heat-press bonding was performed to obtain a wet friction plate.

The resulting wet friction plate had a porosity of 40% and 92% of the total number of pores had a pore diameter of 5 to 100 μm.

The friction characteristics of this wet type friction plate are shown in SAE # 2.
It was measured by a testing machine, and the delamination strength was repeatedly measured by a compression testing machine. The conditions are shown in Tables 1 and 2.

[Table 1]

[Table 2]

In the friction test, the motor was operated at 1800 rpm.
After rotating for 20 seconds, the clutch was engaged, inertia was absorbed, and stopped for 10 seconds. This cycle was repeated 200 times. After that, the dynamic friction coefficient was measured to be 0.15.
It showed a high value of 4. After continuing the test and repeating 5000 times, the dynamic friction coefficient was measured again.
A stable characteristic was obtained with almost no change from 152. The wear amount after 5000 times was as small as 20 μm and the static-dynamic ratio was 0.87, which was a small value, which was a good value.

In the repeated compression test, the actual surface pressure is 100 kg.
The friction material mating plate was pressed against the clutch for 2 seconds at / (square centimeter), and then pressure-removed for 10 seconds to set this cycle to 1. Continue this test to 10,000
The amount of compression was measured by checking the presence or absence of delamination of the friction material every 0 times. Delamination was not observed even after performing the test 1,000,000 times, and the compression amount was as small as 25 μm, which was good.

Comparative Example 1 The tests shown in Tables 1 and 2 were carried out using a commercially available paper wet friction material.

The dynamic friction coefficient after 200 times is 0.149,
After 5,000 times, the coefficient of dynamic friction is 0.146, and the wear amount is 4
The value was 0 μm and the static-dynamic ratio was 0.95, which was a good value. However, in the repeated compression test, delamination occurred after 110,000 times, and it was impossible to continue the test thereafter.

[0027]

In the present invention, since the friction material base material has a three-layer structure in which a woven cloth is interposed between dry nonwoven cloths, the basis weight of the dry nonwoven cloth, the weight of the woven cloth, and the dry nonwoven cloth and the woven cloth are provided. By changing the ratio of, it is possible to control the porosity and pore diameter of the final finished friction material, and by complementing the drawbacks of non-woven fabric and woven fabric, it has a high dynamic friction coefficient and a good static-dynamic ratio. Moreover, it is possible to obtain a friction material having excellent friction material delamination strength even under high load conditions.

In the invention of claim 2, the porosity is 25 to 70.
%, And by setting 75% or more of the total number of pores to a pore diameter of 5 to 100 μm, a friction material having a higher dynamic friction coefficient and a better static-dynamic ratio can be obtained, and the porosity and the pore diameter can be increased. By specifying within this numerical range, the amount of wear can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a friction material.

FIG. 2 is a perspective view of a sheet-shaped intermediate product and a ring-shaped product.

[Explanation of symbols]

 10 Friction Material 12 Nonwoven Layer 14 Woven Layer 16 Nonwoven Layer 18 Friction Modifier Layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ryuichi Saito 1-17-4 Emino Nishi, Eniwa City, Hokkaido (72) Inventor Toshihiko Kotsumi 3277-2 Mamitsuka, Isesaki City, Gunma Prefecture (72) Inventor Katsuhiro Mori Horiguchi, Isesaki City, Gunma Prefecture Town 110 (72) Inventor Yasushi Otsuka One-share company, Otsuka, 1815 Monma, Kasamatsu-cho, Hashima-gun, Gifu Prefecture

Claims (2)

[Claims] 1. A friction material base material having a three-layer structure in which a woven fabric is interposed between dry nonwoven fabrics, the surface of which is filled with a friction modifier, and the entire three layers of which are impregnated with a thermosetting resin are compressed. A wet friction material characterized by being molded. 2. The wet friction material according to claim 1, wherein the porosity is 25 to 70%, and 75% or more of the total number of pores has a pore diameter of 5 to 100 μm.