JPH0555734B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a friction material containing resin particles, and more particularly to a friction material containing resin particles used in drum brakes and disc brakes of vehicles.

(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.; A friction material in which a plate (hereinafter sometimes referred to as a plate) made of a metal hydride is integrally bonded is widely used.

In such a friction material, the surface of the lining layer bonded to the plate comes into contact with a drum brake or disc brake when the vehicle is moving.

However, in brakes using such conventional friction materials, a fade phenomenon may occur in which the braking force becomes unstable.

This phenomenon occurs because frictional heat caused by braking during high-speed driving is accumulated in the lining layer, resulting in a significant decrease in the friction coefficient of the friction material.

In order to prevent a significant drop in the coefficient of friction caused by frictional heat and improve fade resistance,
No. 59-74179 proposes a friction material comprising a lining layer containing a granular copper-lead alloy.

(Problems to be Solved by the Invention) The friction material proposed in the above publication can have a higher porosity than conventional friction materials, and can quickly remove heat such as frictional heat from the lining layer. Therefore, the friction coefficient of the friction material does not decrease significantly and the fade resistance can be improved.

However, brakes using this friction material have the disadvantage that the brake noise is loud when the brake is operated, and there is a need to reduce the brake noise.

Furthermore, powdered or fibrous thermosetting resin is generally used as the binding material used in friction materials, and as shown in Figure 7, the manufacturing process requires a preforming process for the lining layer. Since the process has become complicated, it is desired to simplify the manufacturing process, especially the preforming process.

Therefore, an object of the present invention is to provide a friction material that can reduce brake noise as much as possible while improving fade resistance, and that can omit the preforming process of the lining layer in the manufacturing process of the friction material. It is on offer.

(Means for Solving the Problems) The present inventors have discovered that, in a friction material consisting of a lining layer containing a granular copper-lead alloy, the cause of increased brake noise is the stress applied to the granular copper-lead alloy from the outside. On the other hand, considering that this is because it is a rigid body, we mixed various granular resins that can be deformed in response to external stress and examined the fade resistance, etc.

As a result, a friction material obtained by granulating a thermosetting resin, which is normally used as a binder, and blending it into a lining material, has excellent fade resistance and reduces brake operation noise, and can be used in the lining layer. I learned that I could omit the preforming process of
We have arrived at the present invention.

That is, the present invention provides a friction material in which a metal plate is integrally bonded to a lining layer containing a thermosetting resin, in which the thermosetting resin is in the form of granules, and the granules are in the lining layer. A friction material containing resin particles is characterized in that the resin particles are substantially uniformly dispersed in the resin particles.

(Function) According to the friction material containing resin particles of the present invention, the porosity can be increased compared to conventional friction materials,
Since the heat generated by frictional heat etc. can be quickly discharged from within the lining layer, the fade resistance can be improved without significantly lowering the friction coefficient of the friction material due to heat accumulation.

Moreover, since the resin granules act as a cushion against the stress applied during brake operation, brake operation noise can also be reduced.

In addition, in the manufacturing process of friction materials, since the resin is in the form of granules and does not easily scatter, the lining layer can be directly heat- and pressure-formed without preforming, simplifying the manufacturing process. can be converted into

(Example) The present invention will be explained in more detail with reference to the drawings.

FIG. 1a is a front view showing an embodiment of the present invention, showing a friction material in which a lining layer 1 is bonded to a plate 2. FIG.

A cross-sectional view of such a friction material is shown in FIG. 1b.

FIG. 1b is a cross-sectional view taken along the line A-A in FIG. The lining layer 1 and the plate 2 are firmly bonded together.

This lining layer 1 contains metal powder such as iron or copper,
Organic fillers such as aramid fibers, inorganic compounds such as graphite and antimony oxide, and inorganic fillers such as barium sulfate are mixed uniformly. The particles of these compounds cannot be identified with the naked eye.

In such a lining layer 1, the grain size is 0.5 to 3 mm.
Granular bodies (hereinafter sometimes referred to as resin particles) 3, 3, etc. made of thermosetting resin are substantially uniformly dispersed.

The friction material shown in FIG. 1 can be manufactured by the steps shown in FIG. 2.

First, through holes 4, 4 are 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.

Separately from such plate processing steps, the lining material forming the lining layer is mixed and measured.

The lining materials in this example include iron and copper as metal powder, graphite as an inorganic compound, antimony oxide, aramid fiber as an organic filler, barium sulfate as an inorganic filler, and particle size.
Resin grains made of phenol resin with a size of about 0.5 to 3 mm are used.

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

The plate thus processed and the lining material, which is made of a mixture of raw materials and reduced in weight, are bonded together by heating and pressure molding.

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 this apparatus, the plate 2 is set on the lower mold 8 so that the through holes 3 of the plate 2 are fitted into the convex portions 5 of the lower mold 8.

The tip of the recess 5 is adjusted so that it is located approximately in the middle of the through hole 3.

Furthermore, the upper mold 7 is set on the plate 2, and the lining material mixed and measured in advance is placed on the plate 2.
A mold formed by the upper mold 7 and the upper mold 7 is filled.

Next, by pressurizing and heating the lining material filled with the press mold 6, a portion of the lining material enters the through holes 4, 4, and the lining layer 1 and the plate 2 are bonded together. At the same time, the phenol resin particles in the lining layer 1 firmly bond the lining materials together.

The heating temperature during heating and pressure molding is the same as that used in conventional friction material molding.
A temperature of 80-120°C, which is lower than 160-170°C, can be employed. Such low-temperature molding allows the lining materials to be firmly bonded to each other while maintaining the particle size of most of the blended resin particles at the time of blending.

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 1 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.

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. After that, the friction material is made into a product through post-processing steps such as flat polishing to polish the surface of the lining layer 1 and painting.

Even at such heat treatment temperatures, since the blended resin particles are made of thermosetting resin, some of them become fluidized by the heat treatment and bind the lining materials together, but the particle size of the resin particles after heat treatment is the same as that at the time of compounding. It is approximately the same as the particle size.

The porosity of the friction material obtained in this way is 17 to 25.
%, which is larger than conventional friction materials, which have a porosity of about 5 to 15%.

When measuring the friction coefficient (μ) of the friction material of the present example (example) and the conventional friction material (comparative example) by pressing the friction material against a rotating disk,
The results of the investigation by changing the rotational speed of the rotating disk are shown in the fourth section.
As shown in the figure. In FIG. 4, the number of rotations of the rotating disk is converted into speed (Km/HR).

As a conventional friction material, resin powder was used in place of the resin granules used in this example, and it was manufactured by the manufacturing process shown in Fig. 7, and the heating temperature for heating and pressure molding was 160 to 170°C. This was obtained in the same manner as in this example except that.

As is clear from FIG. 4, the friction material of this example has a lower friction coefficient (μ) at low speeds than a friction coefficient (μ) at high speeds compared to conventional friction materials.
The rate of decrease in is small and stable, and the fade resistance can be improved.

This is because in the friction material of this example, when the friction material and the rotating disk come into contact, the frictional heat generated is quickly discharged to the outside through the pores of the lining layer 1, and is absorbed into the lining layer 1. This is because heat is difficult to accumulate.

Furthermore, the friction material of this example produces less braking noise when it comes into contact with the rotating disk and brakes the rotating disk, compared to conventional friction materials. It is presumed that this is because the resin grains 3 dispersed within the lining layer of the friction material of this example play the role of a cushion against external stress.

In the friction material of the present embodiment described above, a part of the lining layer 1 enters the through holes 4, 4 of the plate 2, and the lining layer 1 and the plate 2 are bonded together. Since the porosity of the lining layer 1 is large, moisture infiltrates and accumulates in the lining layer 1 through the through holes 4 and 4 during use of the friction material, causing rust etc. and shearing separation between the lining layer 1 and the plate 2. There is a risk of reducing strength.

Therefore, as shown in FIG. 5 or FIG. 6a, the through holes 4, 4 of the plate 2 are substantially closed with water-impermeable layers 9, 19 whose main component is water-impermeable resin. This prevents moisture from entering and accumulating in the lining layer 1 through the through holes 4, 4, thereby preventing the occurrence of rust.

It should be noted that moisture from the surface of the lining layer 1 that comes into contact with the brake drum etc. is easily evaporated by heat such as frictional heat during brake operation and does not accumulate in the lining layer 1.

The friction material shown in FIG. 5 is a lump (for example, a spherical body) made of the same resin as the thermosetting resin granules contained in the lining material in the heating and pressurizing process of the friction material manufacturing process. A part of
After fitting into each of the through holes 4, 4 of the plate 2, the lining material that has been mixed and measured in advance is filled into the mold formed by the upper mold 7 and the plate 2, and then heated and pressure molded. It can be obtained by doing.

Further, by using a hat-shaped molded body 20 shown in FIG. 6b in place of the aforementioned lump, the friction material shown in FIG. 6a can be obtained. When manufacturing such a friction material, a part of the tip of the convex portion of the cap-shaped molded body 20 is fitted into the through holes 4, 4 of the plate 2, and heat and pressure molding is performed.

The block or preventive molded body 20 that is fitted into the through holes 4 and 4 of the plate 2 to form the water-impermeable layers 9 and 19 shown in FIGS. 5 and 6 may contain 40 wt% or more of resin. , the through holes 4, 4 of the plate 2 can be easily closed.

The friction material obtained in this manner is such that the lining layer 1 and the plate 2 are integrated while the through holes 4, 4 of the plate 2 are substantially closed by the water-impermeable layers 9, 19 made of water-impermeable resin. is firmly bonded to
Moreover, resin grains 3 are dispersed within the lining layer 1.

Similar to the friction material shown in FIG. 1, such a friction material can improve fade resistance and reduce brake operation noise, and there is no concern that the shear peel strength of the friction material will decrease during use. It can be resolved.

(Effects of the Invention) The resin granule-containing friction material of the present invention can reduce brake operation noise while improving fade resistance, and is therefore ideal for use as a friction material for automobile brakes.

Moreover, since a part of the manufacturing process can be omitted, manufacturing costs can also be reduced.

[Brief explanation of the drawing]

Figure 1 is a front view and cross-sectional view showing one embodiment of the present invention, Figure 2 is a process diagram showing the manufacturing process for manufacturing the friction material shown in Figure 1, and Figure 3 is the heating shown in Figure 2.・Cross-sectional view of the device used during pressure molding, No. 4
The figure is a graph showing the relationship between the friction coefficient (μ) of the friction material and the speed of the rotating disk braked by the friction material.
5 and 6 are cross-sectional views showing other embodiments, and FIG.
The figures each show process diagrams showing the manufacturing process of conventional friction materials. In the figure, 1... lining layer, 2... plate, 3... resin granules, 4... through hole.

Claims (1)

[Claims] 1. In a friction material in which a metal plate is integrally bonded to a lining layer containing a thermosetting resin, the thermosetting resin is in the form of granules, and the granules are substantially uniformly dispersed within the lining layer. A friction material containing resin particles.