JP3030059B2 - Forming method of friction material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for molding a raw material mixture of a friction material for automobiles and industrial machines which is pressed at a high pressure using rubber, resin or the like as a binder. It is.

[Conventional technology]

One of the friction material forming methods is a low-temperature press forming method. This is done by placing the raw material mixture in a mold heated by an electric heater at a low temperature (about 50 to 80 ° C) so that the curing reaction of the binder such as rubber and resin contained therein does not occur, and is applied by a hydraulic press. In the method of pressure molding, the curing reaction of the molded article is performed in a heat treatment in a later step.

[Problems to be solved by the invention]

However, the press forming temperature of the friction material in the above-mentioned low-temperature press forming method is about 50 to 80 ° C. as described above. To heat this temperature, the hydraulic press is equipped with a heating device capable of controlling the temperature. In addition, since the above-mentioned press forming temperature has a large difference from the press forming temperature (140 to 190 ° C.) used for general friction material forming, temperature control cannot be performed with the same forming machine. However, there is a problem that a dedicated molding machine for low-temperature molding must be required.

Further, in the conventional molding method, a waiting time of 1 to 2 hours is required after the start of heating until the temperature condition is stabilized, so that there is a problem that the working efficiency is poor.

Accordingly, an object of the present invention is to provide a molding method that does not require a heating device and that can perform pressure molding while heating a raw material mixture of a friction material to a desired low temperature.

[Means for solving the problem]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a configuration in which a raw material mixture of a friction material having rubber, resin, or the like as a binder is housed in a mold in a hydraulic press, and the raw material mixture is mixed. To a vibration, which can arbitrarily set vibration conditions such as frequency, amplitude, waveform, displacement at the start and end of vibration, time, and the like, and press-mold the raw material mixture by self-heating by the fine vibration. It is characterized by the following.

That is, the inventor of the present invention, when pressure-forming a raw material mixture of a friction material using rubber, resin or the like as a binder, puts the raw material mixture into a mold and pressurizes while repeatedly applying microvibration. The inventor has found that the raw material mixture self-heats and reaches a predetermined temperature in the low-temperature press molding method, thereby achieving the present invention.

[Function of the Invention]

In the molding method of the present invention, pressure molding is performed while imparting micro-vibration to the raw material mixture of the friction material. By controlling the self-heating value of the raw material mixture by setting it to an arbitrary value suitable for the raw material mixture, the molding temperature required for press forming of the friction material structure by the low-temperature press molding method is generated, and processing according to the purpose is performed. Molding can be performed.

Therefore, unlike the conventional method, it is not necessary to equip the press molding machine with a heating device or the like capable of controlling the temperature.

 Next, the molding method of the present invention will be described with reference to FIG.

In FIG. 1, 1 is an upper mold, 2 is a lower mold, 3 and 4 are base plates of the upper mold 1 and the lower mold 2 respectively, 5 is a heat insulating material, 6 is a differential transformer, and 7 is a hydraulic pressure. In a press body having a cylinder 8 attached, a heat insulating material 5 is interposed between the base plate 3 and the hydraulic cylinder 8 and between the base plate 4 and a pedestal of the press body 7. 6 is mounted on the press body 7.

9 is a function generator for setting vibration conditions, 10 is a servo amplifier for calculating and amplifying and outputting a feedback signal from the differential transformer 6 and a command signal from the function generator 9, and 11 is a command from the servo amplifier 10. Actuated servo valve, 12
Is a hydraulic pressure source, and the hydraulic cylinder 8 is operated by hydraulic pressure from a servo valve 11 supplied from a hydraulic pressure source 12. The operating cores of the upper mold 1 and the differential transformer 6 are mounted.

An example of an apparatus used for carrying out the present invention is constituted as described above. A molding method of a friction material using this apparatus will be described as follows.

First, vibration conditions to be applied to the raw material mixture of the friction material to be molded are set in the function generator 9 as shown in the pattern in FIG. 4, and the raw material mixture is put into the lower mold 2.

Next, when the apparatus is turned on, the servo valve 11 is actuated by a command signal from a servo amplifier 10 which receives a command signal from the function generator 9 and a signal from the differential transformer 6 to calculate and amplify and output the signal, thereby operating the fluid. Hydraulic pressure from the pressure source 12 operates the hydraulic cylinder 8 through the servo valve 11. The hydraulic cylinder 8 lowers the rod, and the upper mold 1 repeatedly press-molds the raw material mixture in the lower mold 2 while applying the micro-vibration set according to the pattern shown in FIG. It is.

The raw material mixture is repeatedly pressurized while being subjected to micro-vibration by the upper mold, so that the raw material mixture self-heats and reaches a temperature equivalent to that heated, and gas generated inside is released, and the entire molded product is released. In addition to the uniformity of the density of the raw material mixture, the upper die 1 is pressed into the lower die 2, so that the raw material mixture does not protrude from the die, the burrs generated on the molded product are extremely small, and high quality molding is achieved. Product is obtained.

〔Example〕

 Next, examples of the present invention will be described.

Molded sample size disc pads: compact car for about 105 mm × 45 mm Material Binder Resin Fibers and Textiles: aramid fibers, steel fibers molding conditions: Pressure 500 kg / cm ^2: Temperature 50 ° C. (mold temperature room temperature): Processing time 40 sec + 20sec: Frequency 10 Hz: Amplitude 1.5 mm Table 1 shows the physical properties and performance test results of the product obtained by molding and heat treatment as described above.

Further, the temperature rise pattern inside the friction material during molding was as shown in the table of FIG.

That is, according to the molding method of the present invention, a product equivalent to the conventional method can be obtained without using a heating device.

In the above embodiment, only the formation of the disk pad has been described, but the present invention can be applied to the formation of other brake linings and clutch facings.

〔The invention's effect〕

The present invention is as described above. In press forming of a friction material manufacturing using a rubber, a resin or the like as a binder by a low-temperature press forming method, instead of heating the raw material mixture by a heating device such as an electric heater, the raw material mixture is used. By applying micro-vibration to self-heating, the heating device provided in the conventional molding device becomes unnecessary, so that not only the device can be simplified, but also in the conventional device, after heating is started. In addition, since the waiting time required until the temperature condition becomes stable is not required, the working efficiency can be improved.

Further, by turning off the heating device of a general high-temperature and high-pressure molding device and using the vibration molding of the present invention, the molding device can be used in combination.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus used in the molding method of the present invention, FIG. 2 is a molding die for a disk pad, a is a plan view of a lower die, b is a vertical sectional front view, and c is an upper die. FIG. 3 d is a vertical front view of the same, FIG. 3 is a disk pad formed according to the present invention using the above mold, a is a plan view, b is a side view thereof, and FIG. FIG. 5 is a chart showing an example of a pattern, and FIG. 5 is a chart showing a temperature rise pattern inside the friction material during molding.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 43/00-43/58 B29B 11/00-11/16

Claims (1)

(57) [Claims] 1. A raw material mixture of a friction material having rubber, resin or the like as a binder is accommodated in a mold in a hydraulic press, and the raw material mixture is subjected to frequency, amplitude, waveform, displacement at the start and end of vibration, and time. A method for forming a friction material, comprising: applying micro-vibration capable of arbitrarily setting vibration conditions such as the above, and forming the raw material mixture by self-heating by the micro-vibration.