JP2857468B2 - Manufacturing method of annular friction material - Google Patents

Description

The present invention relates to a method for producing an annular friction material used for clutch facing and the like.

2. Description of the Related Art In a vehicle or the like, an annular clutch facing is attached to a surface of a disk spring on a clutch disk for performing intermittent power transmission between an engine and a transmission. This clutch facing is formed by impregnating and solidifying a glass fiber or an organic fiber with a binder material such as a phenol resin, and is used by being fixed to the peripheral edges of the disk spring with rivets or the like.

By the way, one of the performances required for clutch facing is the burst strength. The burst strength measures the strength against the centrifugal force during high-speed rotation, and corresponds to the strength during actual use. Various studies have been made on the composition, shape, manufacturing method, and the like in order to improve the burst strength accompanying the recent increase in engine output. As one of them, a clutch facing in which a metal reinforcing plate is bonded and fixed to the back side of a friction base material, which is a main part of the clutch facing, that is, the surface facing the disk spring, is known.

[Problem to be Solved by the Invention] When the friction base material and the reinforcing plate are bonded and fixed, it is usual that the adhesive is interposed in the form of a sandwich, and is sandwiched by a jig and thermocompression-bonded. However, since the reinforcing plate and the friction substrate have significantly different coefficients of thermal expansion due to the difference in material, there is a case where a warp having a truncated cone shape occurs after compression. When such a warp occurs, the clutch facing must be mounted while deforming the clutch facing so that the friction surface becomes flat at the time of mounting to the disc spring, and the mounting man-hour has been increased.

Therefore, the present inventors performed thermocompression bonding in a state in which the friction surface was forcibly warped in the direction opposite to the direction of the warpage after thermocompression bonding, so that the displacement was canceled after thermocompression bonding and the friction surface became flat. discovered. However, it has also been clarified that there is a problem that the burst strength is lowered, probably because peeling occurs on the bonding surface when deforming from a warped state during thermocompression bonding to a flat state after thermocompression bonding.

The present invention has been made in view of such circumstances, and has an object to improve the adhesive strength even when thermocompression bonding is performed in a state in which the thermocompression is performed in a direction opposite to the direction of the warpage after thermocompression bonding. I do.

[Means for Solving the Problems] A method for producing an annular friction material of the present invention for solving the above-mentioned problems includes a step of forming a plate-like annular friction base material containing a fiber component and a binder component as main components, Laminating a thin annular metal reinforcing plate on one surface of a friction base material via a rubber-modified phenolic adhesive to form a laminate, and sandwiching the laminate between a pair of crimping jigs and thermocompression bonding A step of integrally bonding and fixing the friction substrate and the reinforcing plate, and a step of taking out the laminate from the crimping jig. The surface of the crimping jig is formed into an arcuate cross section, and the laminate is crimped during crimping. It is characterized in that the laminate is warped in the opposite direction by cooling and the friction surface is deformed so as to be substantially coplanar.

As the friction base material, a friction base material similar to a conventional one can be used, and the main components are a fiber component and a binder component. As the fiber base material, inorganic fibers such as glass fibers, cananite fibers, potassium titanate fibers, and kaolin fibers; or organic fibers such as aromatic polyamide fibers, linter pulp, polyester fibers, and carbon fibers; and steel wires and brass wires. Various types of metal wires can be used. In addition to the fiber component, various powdery fillers such as silica, talc, calcium carbonate, diatomaceous earth, cashew dust, graphite, and rubber powder, or friction modifiers can be used. And the binder component binds and holds these fiber components and powdery components, and melamine resin,
A thermosetting resin such as a phenol resin is generally used. In some cases, rubber is impregnated and used as a part of the binder in order to improve the friction performance.

In order to form a friction base material, for example, the above fiber component is spun into a string shape while containing the above powdery component, and impregnated with a binder. Then, it is wound into a spiral shape or the like to form an annular shape, and thermoformed to obtain a plate-shaped annular friction base material. It can also be formed by molding.

The reinforcing plate is made of metal and is fixed to one side of the friction base material (opposite to the friction surface) to reinforce the metal. Various types of metals or alloys can be used. Alloys are particularly recommended.
And it is desirable that the thickness of the reinforcing plate is made thin as long as the strength can be maintained.

As the adhesive for bonding and fixing the friction substrate and the reinforcing plate, a known commercially available rubber-modified phenol-based adhesive is used. With other adhesives, the adhesive strength after thermocompression bonding cannot be obtained, and the burst strength decreases.

[Operation] In order to manufacture the annular friction material of the present invention, a friction base material and a reinforcing plate, which are separately formed, are first laminated via a rubber-modified phenolic adhesive. Next, the entire body is sandwiched between a pair of crimping jigs and heated and crimped. Here, the surface of the crimping jig has a shape that is warped in a direction opposite to the direction warped after the crimping when the friction base material and the reinforcing plate are thermocompressed in a flat state. That is, thermocompression bonding is performed with the friction substrate and the reinforcing plate warped. The heating temperature and the heating time are determined according to the bonding conditions of the adhesive. When the annular friction material is removed from the crimping jig, the annular friction material warps in the opposite direction from the already warped shape due to shrinkage due to cooling, the displacement is absorbed, and the friction surface becomes a flat shape with substantially the same plane. .

In addition, since a rubber-modified phenolic adhesive is used for the adhesive, it flexibly follows the displacement while maintaining the adhesive strength,
And since this adhesive has a high affinity with the binder component of the friction substrate, it is presumed that the adhesive strength can be maintained high.

[Effect of the Invention] Therefore, according to the annular friction material of the present invention, since the flat shape is obtained after thermocompression bonding, the work of attaching to the attached portion becomes easy. Further, since the adhesive firmly adheres the friction substrate and the reinforcing plate, the adhesive has a high burst strength and can be used under high-speed rotation conditions.

[Examples] Hereinafter, specific examples will be described.

FIG. 1 shows a clutch facing which is an annular friction material according to an embodiment of the present invention. This clutch facing
It comprises a friction substrate 1, a reinforcing plate 2, and an adhesive layer 3 interposed between the friction substrate 1 and the reinforcing plate 2.

The friction substrate 1 has an outer diameter of 236φ, an inner diameter of 140φ, and a thickness of 3.0mm, and is mainly composed of a fiber component such as glass fiber and a phenol resin and rubber as a binder.
The reinforcing member 2 is made of A2017P-T3 aluminum, has the same shape as the friction substrate 1 in a plan view, and has a thickness of 0.5 mm. The adhesive 3 is a rubber-modified phenol resin-based adhesive (“CS271
1 "Cemedine Co., Ltd.). This clutch facing was manufactured as follows.

A single yarn was formed by spinning 30 parts by weight of a glass fiber, and was joined with 5 parts by weight of a brass wire to form a cord. The string body was impregnated with 10 parts by weight of a phenol resin at a solid content, and then immersed in a compounded rubber solution dissolved in a solvent, and 55 parts by weight of the compounded rubber was impregnated and adhered to the solids.

Next, the cord body impregnated with the binder was wound by a thermoid method to form an annular wound product. After the thermoforming, a polishing treatment was performed to form the friction substrate 1.

By polishing the friction substrate 1 separately with sandpaper or roughening the surface with a shot or the like, a reinforcing plate 2 having a surface roughness of 10 μm depth and a rubber-modified phenol-based adhesive are interposed. After drying at 70 ° C. for 10 minutes, the laminate is sandwiched between crimping jigs 4 and thermocompressed as shown in FIG. Here, the crimping jig 4 includes an upper mold 40 and a lower mold 41.
The upper mold 40 has a ring-shaped concave surface 40a that is deeper toward the center and shallower toward the periphery, and the lower mold 41 has a ring-shaped convex surface 41a that protrudes higher toward the center and lower toward the periphery. Have been. Then, the laminate is placed between the concave surface 40a and the convex surface 41a, and heated at 180 ° C. for 20 minutes at a pressure of 10 kg / cm ² to perform thermocompression bonding. At this time, the laminate 1 ′ has a concave surface 40 a and a convex surface 4 a.
It is formed along the shape of 1a and has a truncated cone shape inclined with respect to the axial direction. When the laminate 1 ′ is removed from the crimping jig 4 after the thermocompression bonding, the laminate 1 ′ warps in the opposite direction with cooling, the deformation is eliminated, and the friction surface becomes a flat shape having substantially the same plane.

The obtained clutch facing was subjected to a bending test in which it was bent at 90 degrees, and the adhesive strength of the bonded portion was determined. As a result, no separation was observed at the interface between the reinforcing plate 2 and the adhesive layer 3 and at the interface between the friction substrate 1 and the adhesive layer 3, and about 5% of the separation was observed inside the adhesive layer 3. Only showing excellent adhesive strength.

In addition, when the burst strength of the obtained clutch facing was measured, it showed excellent burst strength without bursting even at a rotation speed of 16000 rpm or more. The results are shown in Table 1.

That is, since the clutch facing of the present embodiment has a flat shape, the number of steps for attaching to the clutch spring is small, and the clutch facing can be easily attached. In addition, since it has a reinforcing plate and is integrally laminated and has a high adhesive strength, it can be mounted on an automobile having a high-speed engine.

Comparative Example A polyimide adhesive ("TA905" manufactured by Mitsui Petrochemical Co., Ltd.) and a vinyl-modified phenolic adhesive ("Cemedine # 720" manufactured by Cemedine Co., Ltd.) were used as adhesives. Clutch facings of the respective comparative examples were formed in the same manner as in the examples except that they were integrated under the drying and pressure bonding conditions shown. The bending test and burst strength measurement were performed in the same manner, and the results are shown in Table 1.

Table 1 shows that the clutch facing of each comparative example is inferior in the adhesive strength and the burst strength as compared with the examples.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a clutch facing as an annular friction material according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a state in which a thermocompression bonding step is performed when manufacturing the clutch facing. DESCRIPTION OF SYMBOLS 1 ... Friction base material 2 ... Reinforcement plate 3 ... Adhesive layer 4 ... Crimping jig

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Moto Hyodo 2-1-1 Asahi-cho, Kariya-shi, Aichi Aisin Seiki Co., Ltd. (72) Mikio Harada 2-1-1 Asahi-cho, Kariya-shi, Aichi Aisin Seiki (56) References JP-A-2-11938 (JP, A) JP-A-2-11939 (JP, A) JP-A-3-277834 (JP, A) JP-A-1-178230 (JP, A) U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16D 69/00 F16D 13/62 C09K 3/14 C08J 5/14

Claims (1)

(57) [Claims] 1. A step of forming a plate-shaped annular friction base material mainly comprising a fiber component and a binder component, and rubber-modifying a thin annular metal reinforcement plate on one surface of the friction base material. Laminating via a phenolic adhesive to form a laminate,
A step of sandwiching the laminate between a pair of crimping jigs and thermocompression bonding to integrally bond and fix the friction substrate and the reinforcing plate; and a step of removing the laminate from the crimping jig, The surface of the crimping jig is formed to have an arcuate cross-section, and during crimping, the laminate has a bow-shaped cross-section, and upon cooling, the laminate warps in the opposite direction and deforms so that the friction surface becomes substantially the same plane. A method for producing an annular friction material.