JPH0555731B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a friction material and a method for manufacturing the same, and more particularly to a friction material used in drum brakes and disc brakes of vehicles and a method for manufacturing the same.

(Prior art) Friction materials conventionally used in vehicle drum brakes and disc brakes include a lining layer made of a lining material mixed with metal powder, inorganic filler, organic filler, binder, etc. Alternatively, a friction material in which a metal plate having a plurality of through holes (hereinafter sometimes referred to as a plate) is bonded together is widely used.

The surface of such a friction material to which the lining layer is bonded comes into contact with the drum or disc of a drum brake or disc brake when the vehicle is braked.

By the way, when manufacturing such a friction material, the plate and the lining layer are integrated by heating and press-molding a plate-like body made of the lining material and a plate having through holes. .

Therefore, in the resulting friction material, the density of the lining material that penetrates into the through hole is lower than the density of the lining material in other parts of the plate, and the shear peel strength between the lining layer of the friction material and the plate ( (hereinafter simply referred to as shear peel strength),
In other words, there is a drawback that the shear peel strength of the friction material tends to decrease after it is mounted on an actual vehicle and used for a certain period of time.

In order to eliminate this drawback, in Japanese Patent Publication No. 50-37350, a filler having the same composition as the lining layer is filled into the through holes of the plate in advance, and then the plate-like body made of the lining material and the plate are heated and compressed. A manufacturing method using molding has been proposed.

(Problem to be Solved by the Invention) The shear peel strength after use of the friction material obtained by the above manufacturing method is determined by heating and applying a filler having the same composition as the lining layer without filling the through holes of the plate in advance. Although this is improved compared to a friction material obtained by pressure molding, the value is still not sufficient and further improvement is desired.

Moreover, this method requires filling the through-holes of the plate with a filler in advance, and therefore is inferior in workability.

Therefore, the purpose of the present invention is to provide shear peel strength after use (hereinafter sometimes simply referred to as shear peel strength).
An object of the present invention is to provide a friction material that can easily produce a friction material with improved properties and a method for producing the same.

(Means for Solving the Problems) The present inventor has discovered that in conventional friction materials, the decrease in shear peel strength after use is caused by moisture entering the inside of the lining layer from the plate side through the through holes, causing rust, etc. Based on the premise that the above object is achieved, the present invention was arrived at after considering and considering whether it would be effective to substantially block the through-holes of the plate with a water-impermeable substance.

That is, the present invention provides a friction material in which a metal plate having one or more through holes and a lining layer made of a lining material containing a thermosetting resin are bonded together. A friction material characterized in that the through holes of the manufactured plate are substantially closed with a water-impermeable layer containing a water-impermeable resin as a main component, and the water-impermeable layer is integrated with a lining layer. It is.

In addition, when bonding and integrating a metal plate having one or more through holes and a plate-like body made of a lining material containing thermosetting resin, the lining material may be A molded body whose main component is a water-impermeable resin and in which a convex portion is formed at least in part is arranged on a plate-shaped body obtained by molding, and then a molded body arranged on the plate-shaped body This method of manufacturing a friction material is characterized in that at least a portion of the convex portion of the friction material is heated and press-molded while being inserted into a through hole of a metal plate.

In the friction material of the present invention, at least the edge portion of the water-impermeable layer extends beyond the through hole and enters the lining layer, and the edge portion is in close contact with the metal plate. Sealing performance can be further improved.

In addition, in the method for producing a friction material of the present invention, the molded body is a convex body formed from a lump or a sheet-like body, so that it is possible to easily form a molded body having a convex portion formed in at least a part of the molded body. Obtainable.

Furthermore, a flange-like body is provided on the peripheral edge of the convex portion of the molded body, and the outer diameter of the flange-like body is larger than the inner diameter of the through-hole to close the through-hole provided in the iron plate. The sealing performance of the water-impermeable layer can be further improved.

By containing 40 wt % or more of the water-impermeable resin in such a molded body, the through-holes of the plate can be effectively closed with the water-impermeable resin.

In the present invention, by using a thermosetting resin contained in the lining material as the water-impermeable resin, a friction material having excellent shear peel strength can be easily obtained.

(Function) In conventional friction materials, by filling the through-holes of the plate with a filler having the same composition as the lining material, even if the filling density of the lining material in the through-holes is increased, the through-holes cannot be penetrated from the plate side through the through-holes. It is not possible to completely prevent moisture from entering the lining layer.

Moreover, since the heat generated by contact with the brake drum or disc is difficult to be transmitted to the bonding surface between the lining layer and the plate, moisture that has entered the lining layer stays within the layer and causes rust, etc. This is one of the causes of reducing the shear peel strength of the friction material after use.

In this regard, according to the friction material of the present invention, since the through holes in the plate are substantially blocked by the non-water permeable resin, moisture that enters the lining layer from the plate side through the through holes can be completely prevented. This can significantly improve the shear peel strength of the friction material.

Further, according to the manufacturing method of the present invention, a molded body made of a water-impermeable resin and having a convex portion formed at least in part is disposed on a plate-shaped body made of a lining material molded in advance, and Since at least a portion of the convex portion of the body is inserted into the through hole of the plate, it is extremely easy to mold the molded product without deteriorating workability.

In addition, water droplets etc. that land on the surface of the lining layer are immediately blown away or evaporated by the rotation of the brake drum or disc or the heat generated when the drum or disc contacts the friction material. It is extremely unlikely that moisture will enter the layer from the surface of the lining layer and cause rust.

(Example) The present invention will be explained in more detail using the drawings.

FIG. 1a is a front view of a friction material that is an embodiment of the present invention, and FIG. 1b is a sectional view taken along the line A-A in FIG. 1a.

In the figure, a lining layer 1 and two through holes 3 are shown.
The lining layer 1 is provided with grooves 8.

Lining materials forming the lining layer 1 include metal powders such as iron and copper, organic fillers such as aramid fibers, inorganic compounds such as graphite and antimony oxide, inorganic fillers such as barium sulfate, and phenol resins. A bonding material consisting of a thermosetting resin is mixed.

The through holes 3 of the plate 2 constituting such a friction material are substantially covered by the layer 4 which is made of thermosetting resin which is also included in the lining layer 1 and is integrated with the lining layer 1. is blocked.

Since this layer 4 has a thermosetting resin as its main component, it is water-impermeable and prevents moisture from entering from the plate side, that is, from the direction of the arrow shown in Figure 1b. I can do it.

When a part of this layer 4 (hereinafter sometimes referred to as the water-impermeable layer 4) enters the lining layer 1 as shown in FIG. 1b, the anchoring effect of the water-impermeable layer 4 This further strengthens the bond between the lining layer 1 and the plate 2.

In addition, the edge of the part of the impermeable layer 4 that penetrates into the lining layer 1 is as shown in FIG. 1b.
Being in close contact with the plate 2 in the vicinity of the through-hole 3 can further improve the sealing performance of the water-impermeable layer 4 against moisture.

By the way, the amount of thermosetting resin blended into the lining layer 1 is usually about 12 wt%, as described in the above-mentioned Tokkosho, but it does not substantially block the through holes 3 of the plate 2. Water impermeable layer 4
The sealability of the water-impermeable layer 4 can be significantly improved by setting the blending amount of the thermosetting resin for forming the water-impermeable layer 4 to 40 wt% or more.

In this embodiment, the lower surface of the water-impermeable layer 4 is located within the through-hole 3 of the plate 2 . By doing so, the packing density of the lining material in the lining layer 1 above the through hole 3 can be increased, as will be described later.

The friction material of this example can be manufactured by the steps shown in FIG.

First, a through hole is bored in a metal plate, and the plate is subjected to various surface treatments and then dried.

This surface treatment process includes a degreasing process to degrease the plate, a shot processing process to increase the adhesive strength between the lining layer and the plate by spraying granules toward the plate surface, and a heat treatment process to bond the lining layer and the plate. An adhesive application step is included in which a curable adhesive is applied to the plate surface.

The lining layer is molded separately from such plate processing steps.

In molding the lining layer, raw materials are mixed, then weighed in a predetermined amount, and preformed into a plate-shaped body.

The lining materials used as raw materials in this example include iron and copper as metal powder, graphite and antimony oxide as inorganic compounds, aramid fiber as an organic filler, barium sulfate as an inorganic filler, and barium sulfate as a binder. Phenol resin is used.

Incidentally, examples of the phenol resin include novolac type phenol resin, resol type phenol resin, and the like.

The thus processed plate and the preformed plate-like body are integrally formed and bonded together by heating and pressure molding.

At this time, as shown in FIG. 2a, a block 41 made of phenol resin whose main component is a water-impermeable resin is disposed on the preformed plate-shaped body 21, and at least one part of the block 41 is While inserting the part into the through hole 3 of the plate 2, heat and pressure treatment is performed.

The block 41 disposed on the plate-like body 21 contains phenol resin in an amount of 40 wt % or more, so that the through-holes 3 of the plate 2 can be easily closed. Furthermore, as shown in FIG. 2b, the block 41 may be covered with a lining material that forms the plate-like body 21.

By covering the block 41 with the lining material in this way, the block 41 is less likely to fall during heating and pressure molding, and has good adhesion and conformability to the through holes 3 of the plate 2.

Such heating and pressure molding can be easily performed by using the apparatus shown in FIG.

This device is composed of a press die 6, an upper die 7, and a lower die 8, and the lower die 8 is provided with a convex portion 5.

To perform heating and pressure molding using such equipment,
The plate 2 is set on the lower mold 8 so that the convex portion 5 of the lower mold 8 fits into the through hole 3 of the plate 2.

Note that the tip of the convex portion 5 is adjusted so that it is located approximately in the middle of the through hole 3.

Furthermore, as shown in FIG. 2, the block 41 made of phenol resin disposed on the plate-shaped body 21 is inserted into the through-hole 3 of the plate 2 set on the lower mold 8 and into the upper mold 7. The plate-shaped body 21 is set.

Next, by pressurizing and heating the plate-shaped body 21 with the press die 6, the lining layer 1 and the plate 2 are bonded, and the phenol resin in the lining layer 1 firmly bonds the lining materials together. combine.

Furthermore, the phenol resin in the lumps 41 is fluidized by the heat, forms a layer 4, and substantially closes the through holes 3 of the plate 2, and also penetrates between the lining materials in the lining layer 1 to form a layer 4. 1 and layer 4 are integrated.

In addition, the convex portion 5 of the lower mold 8 is heated and pressurized.
The packing density of the lining material constituting the lining layer above the through holes 3 of the plate 2 can be significantly increased, and the effect of preventing moisture from entering through the through holes 3 can be enhanced. Since it can penetrate, it is also effective in improving the binding strength between the plate 2 and the lining layer 1.

Note that the shape of the lump 41 disposed in the plate 21 may be any shape such as spherical or cylindrical. It's not a problem and it's convenient.

In this example, in order to further perfect the bonding of the friction material obtained by heating and pressure molding in this way, we baked it for about 9 hours in a hot air oven maintained at about 180 to 230 degrees Celsius. do. Through this firing process, the friction material is made into a product through post-processing processes such as grooving to form grooves 8 in the lining layer 1, flat polishing to polish the surface of the lining layer 1, and painting.

The friction material of this example obtained in this way, the lump body 41 and the plate body 21 made of phenol resin.
A friction material (hereinafter referred to as comparative friction material) obtained in the same manner as in this example except that it was not disposed in
The shear peel strength was measured after driving with the device attached to an actual vehicle for a certain period of time. This experiment was conducted three times and the average shear peel strength is shown below.

Friction material of this example: 2240Kg Comparative friction material: 1090Kg Compared to the comparison friction material, the friction material of this example:
Shear peel strength can be significantly improved.

In the embodiments described above, a spherical block 41 made of phenol resin was used, but instead of the block 41, a hat-shaped molded body 51 ( below,
(sometimes referred to as a cap-shaped molded body 51) can be used.

The cap-shaped molded body 51 shown in FIG. 5 is formed by stamping a sheet-shaped body made of phenol resin using a press or the like, and the outer diameter of the brim 52 is the inner diameter of the through hole 3 of the plate 2. omitted for
The outer diameter of the convex portion 53 is approximately the same as the inner diameter of the through hole 3.

As shown in FIG. 6, the hat-shaped molded body 51 is placed on the plate-shaped body 2 while the tip of the convex portion 53 is directed toward the upper or lower surface of the preformed plate-shaped body 21.
Arranged on the surface layer of 1.

At this time, the cap-shaped molded body 51 may be covered with a lining material forming the plate-shaped body 21, as shown in FIG. 6b. By doing so, the cap-shaped molded body 51 is difficult to fall during heating and pressure molding, and the adhesion and conformability to the through-holes 3 of the plate 2 can be improved.

Next, the convex portion 53 of the cap-shaped molded body 51 disposed on the plate-like body 21 is inserted into the through-hole 3 of the plate 2, which has been subjected to various treatments, and heated using the apparatus shown in FIG.・Perform pressure molding.

Through this heating and pressure treatment, a friction material having a cross section shown in FIG. 7 can be obtained, and the cap-shaped molded body 51
The convex portion 53 is an impermeable layer 54 that closes the through hole 3.
The brim portion 52 of the cap-shaped molded body 51 mainly forms the edge of the water-impermeable layer 54 that is in close contact with the plate 2 in the vicinity of the through hole 3.

The water-impermeable layer 54 obtained using the cap-shaped molded body 51 has a concave shape at the approximate center of the interface with the lining layer 1, but this does not affect the characteristics of the water-impermeable layer 54 in any way. It is possible to exhibit a shear peel strength comparable to that of the friction material having the cross section shown in FIG. 1b.

Moreover, the method of using such a cap-shaped molded body 51 is that the cap-shaped molded body 51 can be obtained by punching and forming a sheet-like body made of thermosetting resin using a press or the like, as described above. ,
This method can easily mold a large number of cap-shaped molded bodies 51, and is an industrially excellent method.

Incidentally, the spherical mass 41 shown in FIG. 2 may also be provided with a flange-like portion 52 shown in FIG. 5, and the water-impermeable layer 4 obtained using such a mass 41
The edge portion of [Fig. 1b] can be firmly attached to the plate 2 near the through hole 3, and the
can further improve the sealing performance.

(Effects of the Invention) According to the present invention, by heating and pressurizing at least a part of the convex portion of a molded body made of a water-impermeable resin while inserting it into a through hole provided in a plate, The through-holes of the plate can be substantially sealed with a water-impermeable resin, and rust etc. caused by moisture entering through the through-holes of the plate can be prevented from occurring.

Therefore, it is possible to improve the shear peel strength and water resistance of the resulting friction material, further improving the safety of vehicles and improving the workability of the manufacturing process of the friction material, as proposed in Japanese Patent Publication No. 50-37350. It can be significantly improved compared to existing methods.

[Brief explanation of the drawing]

Figure 1a is a plan view of the friction material of the present invention, Figure 1b
is a cross-sectional view taken along the line A-A in FIG. FIG. 3 is a sectional view of an apparatus used to heat and pressure mold the plate-like body 21 and the plate 1, and FIG. 4 is a process diagram for manufacturing the friction material of the present invention.
FIG. 5 is a perspective view of a hat-shaped molded body 51 used in another embodiment, and FIG. 6 is a plate-shaped body 2 made of a lining material.
FIG. 7 is an explanatory diagram illustrating insertion of the convex portion 53 of the cap-shaped molded body 51 disposed in the cap-shaped molded body 51 into the through-hole 3 of the plate 2, and FIG. Figures are shown respectively. In the figure, 1... lining layer of product friction material, 2... plate, 3... through hole of plate 1, 4, 54... layer closing the through hole 3, 21...
...Plate-shaped body made of lining material, 41... Blocked body made of water-impermeable resin, 51... Cap-shaped molded body,
52... Flange-shaped part of the cap-shaped molded body 51, 53... Convex part of the cap-shaped molded body 51.

Claims (1)

[Claims] 1. A friction material in which a metal plate having one or more through holes and a lining layer made of a lining material containing a thermosetting resin are bonded together. A friction device characterized in that the through holes of the metal plate are substantially closed with a water-impermeable layer containing a water-impermeable resin as a main component, and the water-impermeable layer is integrated with a lining layer. Material. 2. The friction material according to claim 1, wherein at least an edge portion of the water-impermeable layer extends beyond the through hole and enters the lining layer, and the edge portion is tightly attached to a metal plate near the through hole. 3. When bonding and integrating a metal plate with one or more through holes and a plate-like body made of a lining material containing a thermosetting resin, the lining material is molded in advance. A molded body whose main component is a non-water-permeable resin and in which a convex portion is formed at least in part is placed on the plate-shaped body obtained by the process, and then the molded body placed on the plate-shaped body is A method for manufacturing a friction material, which comprises heating and press-molding while inserting at least a portion of a convex portion into a through hole of a metal plate. 4. The method for producing a friction material according to claim 3, wherein the molded body is a block. 5. The method for producing a friction material according to claim 3, wherein the molded body is a convex body obtained from a sheet-like body. 6. The friction according to any one of claims 3 to 5, wherein the molded body is provided with a flanged body at the peripheral edge of the convex portion, and the outer diameter of the flanged body is larger than the inner diameter of the through hole. How the material is manufactured. 7. The method for producing the friction material according to claim 1 or claim 3, wherein the water-impermeable resin is a thermosetting resin contained in the lining material. 8. The method for producing a friction material according to any one of claims 3 to 6, wherein the molded article contains 40 wt% or more of a water-impermeable resin.