JPH084812A - Brake lining - Google Patents

Abstract

PURPOSE:To remarkably enhance material design freedom of a brake lining by laminating an outer layer having such a high friction characteristic as hardness and bending strength exhibit specific values to an inner layer having such high mechanical strength as hardness and bending strength exhibit other specific values. CONSTITUTION:In a brake lining 1 used for a brake for a medium size or large size vehicle, an outer layer 2 is formed to have such a high friction characteristic as Rockwell hardness is 40 less than 70HRS, preferably 50-65HRS, and bending strength based on three-point bending is 25MPa or higher and less than 40MPa, preferably 30-33-MPa, while an inner layer 3 is formed to have such high mechanical strength as Rockwell hardness is 70-90HRS, preferably 75-85HRS, and bending strength based on three-point bending is 40-50MPa, preferably 45-50MPa. With this constitution, quantity of use of reinforcing fiber can be reduced and material design freedom can be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake lining used as a friction material for a brake for a medium-sized or large-sized vehicle such as a truck, a bus and a dump truck.

[0002]

2. Description of the Related Art Conventional brake linings used for braking medium- or large-sized vehicles such as medium-sized to large-sized trucks, buses, dump trucks, etc., have a single-layer construction to ensure the frictional characteristics inherent to the friction material and to achieve a shoe-and-shoe structure. The mechanical strength as a lining assembly is ensured at the same time (the friction characteristic is 60 to 80 by Rockwell hardness).
HRS and mechanical strength are 35-35 by bending strength by three-point bending
50 MPa).

The composition of this brake lining is
In order to obtain the above-mentioned friction characteristics and mechanical strength, generally, a phenol resin binder 10 to 20% (weight%, the same applies below), an organic friction modifier 5 to 20% such as resin dust, and an inorganic friction adjustment such as copper powder. Agent 2-10%, inorganic filler 35-55% such as barium sulfate, organic fiber substrate 5-15% such as aramid fiber, inorganic fiber substrate 5-15 such as ceramic fiber
%, And a lubricant such as graphite 3 to 15%.

[0004]

In the conventional brake lining, as described above, the single-layer structure serves to secure both friction characteristics and mechanical strength, so that the quality and quantity of the reinforcing fibers contributing to the strength are strict. Therefore, the flexibility of material design of the brake lining is limited, and since a large amount of reinforcing fiber is used, it is possible to simultaneously deal with noise reduction and effectiveness stability, which are the most important issues of the market. This is not possible, and there is a problem of cost increase due to the large amount of expensive reinforcing fibers used.

The first object of the present invention is to greatly improve the degree of freedom in the material design of the brake lining. A second object of the present invention is to provide a brake lining that can simultaneously achieve noise reduction and effective stability.

A third object of the present invention is to provide an inexpensive brake lining.

[0007]

In order to solve the above-mentioned problems, the present invention has a laminated structure in which the lining is functionally separated into a part mainly having a friction function and a part mainly having a strength function as follows. .

<Summary of the Invention> The brake lining of the present invention is essentially a laminate of an outer layer having high frictional properties and an inner layer having high mechanical strength. The high-friction property referred to here is HRS having a hardness of 40 or more and less than 70 by Rockwell and a bending strength of 25 or more and 40 by three-point bending.
It is less than MPa, and high mechanical strength means hardness of 70 to 90 HRS and bending strength of 40 to 50 MPa.

[Component A of Outer Layer] The outer layer has a hardness of 40 to less than 70 HRS by Rockwell, preferably 5
Bending strength of 0-65 HRS and three-point bending is 25
It has a high frictional property of not less than 40 MPa and preferably 30 to 33 MPa. If the hardness and the bending strength are outside the above ranges, respectively, the limitation of the quality and amount of the reinforcing fiber cannot be relaxed or the amount of the reinforcing fiber used cannot be reduced.

The outer layer is a binder 1 in order to obtain the above characteristics.
0 to 20% (weight%, the same below), preferably 12 to 1
4% and organic friction modifier 5-20%, preferably 8-1
5% and inorganic filler 40-60%, preferably 45-5
5% and organic fiber base material 2 to 10%, preferably 4 to 6%
And 3 to 15%, preferably 6 to 12% of a lubricant, and 2 to 15%, preferably 5 to 10% of an inorganic friction modifier as main raw materials. When the mixing ratio of each material is out of the above range, it is not possible to relax the limitation on the quality and amount of the reinforcing fiber or to reduce the amount of the reinforcing fiber used.

A phenol resin or a modified product thereof is usually used as the binder. Organic friction modifiers include resin dust (usually cashew dust), rubber dust, etc.
Preferably, resin dust can be exemplified. Examples of the inorganic filler include barium sulfate, calcium carbonate, calcium hydroxide and the like. Examples of the organic fiber base material include aramid fiber, cellulose fiber, acrylic fiber, and preferably aramid fiber. Examples of the lubricant include graphite and molybdenum disulfide, preferably graphite. Examples of the inorganic friction modifier include metal powder such as copper powder, aluminum powder, iron powder and zinc powder; metal oxide powder such as alumina powder, silica powder (or glass powder) and copper oxide powder; preferably copper powder. It can be illustrated.

The thickness of the outer layer is usually 9 to 12 mm,
It is preferably in the range of 10 to 11 mm.

[Component B of Inner Layer] The inner layer has a Rockwell hardness of 70 to 90 HRS, preferably 75 to 8
5HRS and bending strength of 40-50 by three-point bending
It has a high mechanical strength of MPa, preferably 45 to 50 MPa. If the hardness and the bending strength are outside the above ranges, respectively, similarly to the case of the outer layer, it is not possible to relax the limitation on the quality and amount of the reinforcing fiber or to reduce the amount of the reinforcing fiber used.

In order to obtain the above-mentioned characteristics, the inner layer has a bonding material 10
-20%, preferably 16-18%, organic friction modifier 5-20%, preferably 5-10%, and inorganic filler 35
To 55%, preferably 45 to 50%, and inorganic fiber substrate 1
It is composed mainly of 0 to 30%, preferably 20 to 25%, and an inorganic friction modifier 2 to 5%, preferably 3 to 4%. In addition, if the mixing ratio of each material is outside the above range, can the restrictions on the quality and quantity of the reinforcing fibers be relaxed?
Or the amount of reinforcing fibers used cannot be reduced.

Specific examples of the binder, the organic friction modifier, the inorganic filler, the inorganic fiber base material and the inorganic friction modifier used in the inner layer are as described in the description of the outer layer.
The thickness of the inner layer is usually 4 to 7 mm, preferably 5 to 6
The range is mm.

<Additional Constituent Requirements in the Present Invention> The present invention consists of the above-mentioned essential constituent elements, but can be realized even if the following constituent elements are added.

[Additional Constituent Element C of Outer Layer] In addition to the above essential constituent materials for the outer layer, the outer layer may contain an inorganic fiber base material in an amount of 10% or less, preferably 5% or less. Examples of the inorganic fiber base material include ceramic fibers such as glass fibers and alumina fibers; metal fibers such as steel fibers, copper fibers and brass fibers; potassium titanate fibers; rock wool; carbon fibers; preferably glass fibers.

[Additional Constituent Element D of Inner Layer] In addition to the above essential constituent raw materials for the inner layer, the inner layer may contain an organic fiber base material in an amount of 10% or less, preferably 4% or less. Specific examples of the organic fiber base material are as described above.

[Additional Constituent Element E of Inner Layer] In addition to the above essential constituent materials for the inner layer, the inner layer may contain a lubricant in an amount of 5% or less, preferably 3% or less. Specific examples of the lubricant are as described above.

[Combination of Each Component] As described above, in the outer layer and the inner layer constituting the present invention, in addition to the respective essential components A and B, additional components C, D and E are present.
These can be combined alternatively with the essential components A and B.

For example, a combination of A and B with C, a combination of A and B with D, a combination of A and B with C and D, and the like.

<Dimensions and shapes of the product of the present invention> The dimensions and the shape of the brake lining of the present invention are the same as those of the conventional single-layer type linings used for the brakes of general, particularly medium to large trucks, buses, dump trucks and the like. The same as

The brake lining of the present invention is shown in the drawing as a shoe and lining assembly.
It becomes like ~ 3. Figure 1 is a side view of the shoe lining assembly with this brake lining,
2 is a front view seen from the web side of the assembly, and FIG. 3 is a partially cutaway side sectional view of a main part of FIG.

In FIGS. 1 to 3, 1 is a brake lining, 2 is an outer layer of the lining, 3 is an inner layer of the lining, 4 is a rim (steel) surface of a shoe assembly including a rim 5 and a web 6, and the lining is provided. It is a rivet for fixing. The outer layer 2 is a portion that becomes a sliding surface with a brake drum (not shown), and the inner layer 3
Is a portion which becomes a contact surface with the rim 5 of the assembly.

<Manufacturing Method of the Product of the Present Invention> The brake lining of the present invention can be manufactured basically by the same method as the conventional dry or wet manufacturing method of the single-layer type lining.

That is, in the case of the dry method, for example, the raw material for the inner layer and the raw material for the outer layer are sufficiently stirred and mixed, and the mixture for the inner layer is put into a predetermined mold, and the mixture for the outer layer is layered thereon. After overlapping and preforming integrally, transfer to a heat press for thermoforming, heat treatment, polishing the inner peripheral surface, opening rivet holes for lining fixing, then fixing with rivets to the rim of the shoe assembly, By polishing the outer peripheral surface, a shoe undlining assembly is obtained. In the case of the wet method, an appropriate amount of solvent may be added at the time of stirring both of the blended raw materials, and thereafter, the same operation as in the case of the dry method may be performed. In the case of the wet method, the solvent evaporates and dissipates during molding due to the heat generated during thermoforming.

The manufacturing conditions for both the dry method and the wet method may be the same as those for the conventional single layer lining. That is, the preforming has a surface pressure of 50 to 350 Kgf / cm ² , and the thermoforming has a temperature of 150 to 175 ° C. and a surface pressure of 100 to 350 Kgf / c.
m ² for about ⁶ to 13 minutes and heat treatment at a temperature of 150 to
It is usually performed at 200 ° C. for about 5 to 12 hours.

[0028]

[Action]

<Operation of Essential Components A and B of the Present Invention> The components A and B can alleviate restrictions on the quality and amount of reinforcing fibers and reduce the amount of reinforcing fibers used.

<Operation when the additional component C is added>
The strength of the outer layer is improved.

<Operation when the additional component D is added>
The material dispersibility of the inner layer is improved.

<Operation when the additional component E is added>
The friction coefficient μ of the inner layer is improved.

[0032]

Embodiments of the present invention will be described below with reference to the drawings.

[0033]

Examples 1 and 2 The inner layer compounding raw material and the outer layer compounding raw material of Example 1 shown in Table 1 below; the inner layer compounding raw material and the outer layer compounding raw material of Example 2 were sufficiently stirred and mixed for each layer. did. However, in the case of Example 2, 10% of 20% alcohol was added to 100 parts (weight) of the total amount of the raw materials for each layer during stirring (in this case, the amount of alcohol added can be changed to the range of 3 to 20 parts). . Next, the mixture for the inner layer is put into a predetermined mold, and the mixture for the outer layer is further layered thereon to be integrally preformed, transferred to a hot press, heated and pressure-molded, and subjected to heat treatment. After polishing the inner peripheral surface 3 side and opening a rivet hole for fixing the lining, the rivet 4 fixes it on the steel rim 5 of the assembly base (2L type brake shoe with a drum diameter of 410 mm), and the outer peripheral surface 2 side. Was polished to produce a shoe and lining assembly having a brake lining 1. The outer layers of the linings obtained in Examples 1 and 2 had a thickness of 11 mm and the inner layer had a thickness of 5 mm.

On the other hand, as Comparative Example 1, the mixed raw materials shown in Table 1 were sufficiently stirred and mixed, placed in a predetermined mold, and provided with a single layer lining according to the same preforming, thermoforming and heat treatment methods as in the following Examples. Produced a shoe-and-drying assembly. The thickness of this single layer lining is 16m
m.

[0035]

[Table 1]
(weight%)

Physical properties of the obtained lining (Examples 1 and 2)
In the case of, the inner layer and outer layer), the effectiveness stability, the noise property, and the raw material price are shown in Table 2 together with the manufacturing method applied.

[0037]

[Table 2]

The evaluation methods of effectiveness stability, noise property and raw material price are as follows. Efficacy and stability: Set the sample (Shoe and Drying Assembly) on the braking tester at 20 km / h and 50
Evaluation is made by the ratio of the effectiveness at the initial braking speed of 20 Km / h and the effectiveness at the initial braking speed of 50 Km / h when braking with the hydraulic pressure of 0.3 G at each initial braking speed of Km / h. .
The ideal efficacy stability is when the ratio is 1.

Noise: A ratio of the number of squeal occurrences (squeal occurrence rate) based on the following criteria when the sample is incorporated and 1000 times braking is performed with a hydraulic pressure of 0.3 G at an initial braking speed of 50 Km / h. evaluate.

In the sensory evaluation based on the following evaluation criteria, the generated squeal was only 1 point in each of the examples, but in the case of the comparative example 1, it was between 1 and 3 points. <Evaluation Criteria for Squeaking> 1 point ......... Squeaking but very small. 2 points ......... Squeaking but small. 3 points: It is uncomfortable if this squeal is always present. 4 points: The sound is loud and uncomfortable. 5 points: The sound is very loud and very uncomfortable.

Raw material price: Relative price when the unit price (yen / Kg) of the blended raw material of Comparative Example 1 is 100.

Although the embodiment has been described as a brake lining applied to a drum brake, it can also be applied to a disc brake.

[0043]

The essential components A and B of the present invention are
Since the restrictions on the quality and amount of reinforcing fibers are relaxed and the amount of reinforcing fibers used is reduced, the flexibility of material design in the lining can be greatly improved, and noise reduction and effective stability can be achieved at the same time. The effect is that the lining can be provided.

Further, by the additional components C, D and E,
The effects of improving the strength, improving the dispersibility of the material, and improving the friction coefficient μ are obtained.

[Brief description of drawings]

FIG. 1 is a side view of a shoe and lining assembly including a brake lining according to an example of the present invention.

FIG. 2 is a front view of the shoe and lining assembly of FIG. 1 viewed from the web side.

FIG. 3 is a partially cutaway side sectional view of a main part of the shoe and lining assembly of FIG.

[Explanation of symbols]

 1 ………… Brake lining 2 ………… Outer layer of the same lining 3 ………… Inner layer of the same lining

Claims (8)

[Claims] 1. An outer layer having a high friction property, which has a hardness of 40 to 70 HRS according to Rockwell hardness and a bending strength of 25 to 40 MPa under three-point bending, and a hardness of 70 to 90 HRS and a bending strength. 40 to 50MP
A brake lining formed by laminating an inner layer having high mechanical strength, which is a. 2. The hardness of the outer layer is 50 to 65 HRS.
And the bending strength is 30 to 33 MPa, while the hardness of the inner layer is 75 to 85 HRS and the bending strength is 4
The brake lining according to claim 1, which has a pressure of 5 to 50 MPa. 3. The outer layer comprises 10 to 20% by weight of a binder, 5 to 20% by weight of an organic friction modifier, 40 to 60% by weight of an inorganic filler, 2 to 10% by weight of an organic fiber base material, and a lubricant. 3-1
5% by weight and 2 to 15% by weight of inorganic friction modifier are used as main raw materials, the inner layer is 10 to 20% by weight of binder, 5 to 20% by weight of organic friction modifier, and 35 to 55% by weight of inorganic filler. When,
Inorganic fiber base material 10 to 30% by weight and inorganic friction modifier 2
The brake lining according to claim 1, wherein the main raw material is 5% by weight. 4. The amount of binder in the outer layer is 12-14.
%, The amount of organic friction modifier is 8 to 15% by weight, the amount of inorganic filler is 45 to 55% by weight, the amount of organic fiber base material is 4 to
6% by weight, the amount of lubricant is 6-12% by weight, the amount of inorganic friction modifier is 5-10% by weight, while the amount of binder in the inner layer is 16-18% by weight, organic friction modifier 5 to 10% by weight, the amount of inorganic filler is 45 to 50% by weight,
The brake lining according to claim 3, wherein the amount of the inorganic fiber base material is 20 to 25% by weight and the amount of the inorganic friction modifier is 3 to 4% by weight. 5. The brake lining according to claim 3, wherein the outer layer further contains 10% by weight or less of an inorganic fiber base material. 6. The brake lining according to claim 3, wherein the inner layer further contains 10% by weight or less of an organic fiber base material. 7. The brake lining according to claim 3, wherein the inner layer further contains a lubricant in an amount of 5% by weight or less. 8. The brake lining according to claim 1, wherein the outer layer has a thickness of 9 to 12 mm and the inner layer has a thickness of 4 to 7 mm.