JPH068656B2 - Brake material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a brake material used for braking a vehicle or machinery.

(Prior Art) Some conventional brake materials are made, for example, by mixing a metal material with an abrasion resistant material such as WC or SiC and heating and sintering the mixture. It may be possible. Therefore, the present inventor has proposed that the Japanese Patent Publication No.
In No. 972, it was proposed to use iron powder as a main material, to which carbon and the like and abrasive grains were mixed, and which was subjected to spark sintering. However, the one using this iron powder has a problem that it is not sufficient in terms of wear resistance.

(Problems to be Solved by the Invention) An object of the present invention is to provide a brake material having better wear resistance than the above-mentioned conventional brake materials.

(Means for Solving the Problems) In order to achieve this object, the brake material of the present invention comprises steel wool and carbon powder and / or high carbon cast iron powder as the main materials, and the abrasive particles are mixed with the main materials. It is characterized in that it is formed by sintering.

In the present invention, the mixing ratio of the carbon powder or the high carbon cast iron powder is 3% to 15% in the former case as weight%.
%, The latter is 30 to 60%, and the mixing ratio of the abrasive grains is 10% to 40%. As the abrasive grains, BN and Si are used.
C, SiO ₂ , Si ₃ O ₄ , Si ₃ N ₄ , TiN, Al
₂ O ₃ , ZrO ₂ , diamond, B ₄ C, W ₂ C, T
iC, WC, NbC, TaC and other wear resistant materials are used alone or in combination. When using high carbon cast iron powder, the content ratio of carbon in the iron powder is 3.5.
% Or more is desirable. Further, the brake material of the present invention contains 0.3% or more of a rare earth element, if necessary. In addition, graphite is mixed in to improve wear resistance.

The diameter of the steel wool is about 0.04.
〜0.08mmφ, short fiber curl with a length of about 3-5mm, its composition is as follows: I) 0.1-0.3% C-the balance Fe raw material II) 0.4- 1.3% C-remaining Fe raw material or hardened material III) 18% Cr-8% Ni-remaining Fe material IV) 0.4% C-13% Cr-remaining Fe raw material or hardened material, etc. The above high carbon cast iron powder can be used as the above high carbon cast iron powder and has a particle size of 120 μm or less (up to 100 mesh) to 4
0 μm (-325 mesh), preferably in the form of cutting powder, the composition of which is 2.7-3.6% C
-1.0 to 2.5% Si-0.6 to 0.8% Mn-The balance Fe can be used.

In the case of carrying out the present invention, the sintering may use the heating sintering, but the discharge sintering also burns at the time of sintering even when the wear resistant material such as diamond is used as the hard particles as described above. It is advantageous in that it can be sintered without being used.

Here, in the discharge sintering, the sintering mixture is filled in a mold, and the step mixture is about 0.5 to 1 by a pressing body that also serves as a current-carrying electrode.
With a relatively light compression pressure of about 0 kg / cm ² ,
A relatively low voltage and a large current is supplied from the DC power supply, and at the same time as the DC voltage from the AC or bias AC power supply is higher or lower than the DC current and the frequency is about 2
An alternating current of about 0 to 200 c / s is applied, or a high frequency of a frequency higher than the alternating current of the above frequency is also applied together, or the charging energy of stored electricity is discharged to discharge between the mixture during molding. Along with the generation, Joule heat heating is performed, and if there is a volume change of the mixture during this energization, the pressing body is made to follow so as to gradually increase the compression pressure and the powder-to-powder discharge and Joule heat heating are efficiently continued Then, discharge and energization dissociation, diffusion coupling between particles is performed by an ion diffusion action by an electric current, and a predetermined compression force is applied by the pressing body at the same time as or before and after energization is stopped,
For example, a pressure of about 100 kg / cm ² or more is applied, the pressure is maintained during the progress of cooling, and unless the volume of the sintered body expands, no further pressure is applied continuously to complete the sintering. Is. The sintering time is discharge ion diffusion, which is usually performed in a very short time of about several seconds to several hundred seconds. Therefore, most of the material powders obtained by this electric discharge sintering method can be sintered in a short time, and the diffusion bonding between the powders is perfectly performed, so that the sintered product has extremely high transverse rupture strength. Further, the sintered product can be subsequently subjected to heat treatment such as quenching and annealing, if necessary,
Thereby, the hardness can be further increased.

Examples will be described below.

Example A Steel wool (material 18Cr-8Ni-Fe) having an average wire diameter of 0.06 mmφ and an average flow of 0.3 cm was used as a main material, and cast iron powder having an average particle diameter of 100 μm was mixed at a weight ratio of 4: 6. The main material is BN
11%, SiC 6%, ZrO ₂ 6% powders were mixed,
This is filled in a mold with a diameter of 15 cm and a pressure of 2 cm, and it is about 15 kg /
Pressurize to about cm ² , and apply a superimposed current with a current ratio of direct current to alternating current of 1 Kc / s of about 3: 1 at a current density of about 30 A / cm ² .
Sintering was performed in about 10 seconds.

Example B The steel wool of Example A and carbon powder having an average particle size of 3 μm were mixed in a weight ratio of 6: 4 as a main material.
As weight%, BN 11%, SiC 6%, ZrO ₂ 6%
The respective powders were mixed and sintered in the same manner as above.

Example C 5% of graphite was added to that of Example B, and the same sintering as described above was performed.

Comparative Example D The steel wool of Example A was added to BN6 as a weight percentage.
%, SiC 10%, Al ₂ O ₃ 5% powders are mixed,
Sintering was performed in the same manner as in each of the examples.

Comparative Example E Only the steel wool of Example A was sintered in the same manner as in the above Examples.

Regarding the sintered discs of the above-mentioned respective examples, the relationship between the movement amount (extended contact distance when the brake is applied) and the wear amount of the contact surface under a constant pressure is shown in the drawings. In the figure, A to E show the results of the above-mentioned Examples and Comparative Examples, and X
Shows the results in Example A in which iron powder having an average particle size of 120 μm was used instead of steel wool. As can be seen from the drawings, wear resistance can be improved by using the steel wool of the present invention and using carbon or cast iron powder.

(Effects of the Invention) As described above, the brake material of the present invention is mainly made of steel wool and carbon or cast iron powder, and abrasive grains are mixed and sintered in the main material. It is possible to provide an excellent brake material.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings are comparison diagrams of the wear resistance of the brake material of the present invention and the conventional brake material.

Claims (3)

[Claims] 1. A brake material comprising an abrasive grain of 10 to 40% by weight, steel wool, carbon powder or high carbon cast iron powder as a main material. 2. The brake material according to claim 1, wherein the main material contains 30 to 60% of high carbon cast iron powder. 3. The brake material according to claim 1, wherein the main material contains 30 to 60% of high carbon cast iron powder and 3 to 15% of carbon powder.