JP2002098181A - Manufacturing method for frictional pad for disc brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize thermal energy, to curtail a heat-forming time, to eliminate a waste of a frictional material and to obtain stable quality. SOLUTION: A frictional material composed of a mixture of raw materials is charged into a provisional mold made of a Teflon (R)-family resin, pressurized and provisionally molded. Then, the frictional material is preheated together with the provisional mold, and the preheated frictional material is carried to a heat-forming point together with the provisional mold and charged into a heat-forming female metal mold. Then, a back metal that is preheated, roller- coated with an adhesive and dried is set to the frictional material. The frictional material and the back metal are bonded with the adhesive by pressurizing and heat treatment, and a basic structure for a frictional pad composed of a combination of the frictional material and the back metal is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a friction pad for a disc brake.

[0002]

2. Description of the Related Art Conventionally, in disc brakes for automobiles,
The two friction supporting members provided on the caliper body accommodate friction pads integrally formed by joining a friction material to the holding back metal, and the friction pads are arranged on both sides of the disk rotor. I'm using And such a friction pad is usually manufactured through each main process as shown in FIG. At that time, in the production of friction material,
First, in the raw material measuring step S1, for example, dozens of raw materials for the friction material are weighed to respective predetermined weights using an electronic balance, and are input to the mixer. Next, in the mixing step S2, dozens of types of raw materials are mixed by the mixer for several minutes. Then, the mixed friction material is supplied to a tank for a temporary forming step.

[0003] Further, in manufacturing the back metal, first, in a press working step S3, the back metal is punched out of a steel material into a predetermined shape using a mold provided in a press machine. Next, in the degreasing cleaning step S4, a back metal is put into a cylindrical basket provided in the cleaning machine, the back metal is subjected to immersion rocking cleaning with a cleaning liquid such as an organic solvent, and further, steam cleaning and drying processing are performed. Perform washing. Next, in a shot blasting step S5, rust and the like are removed from the washed back metal by a shot blasting machine, and the surface is roughened to roughen the surface.

[0004] Next, in an adhesive application step S6, a back metal is arranged and conveyed on a dedicated net of the conveyor, and the back metal on the dedicated net is spray-coated with an adhesive at a booth of an adhesive coating apparatus. Next, in a drying step S7, the substrate is heated and dried in a drying furnace for a predetermined time. Then, the adhesive-coated back metal discharged from the drying oven after a cooling time is put into a box, and is conveyed to a temporary molding step or a thermoforming step. In addition, each process S4, S5, S5 of the above-mentioned degreasing cleaning, shot blast, adhesive application, etc.
Lines 6 and 7 are usually formed by conveyor conveyance.

[0005] After preparing the mixed friction material and the backing metal in this way, in a measuring step S8, the mixed friction material stored in the tank is cut out and weighed by a manual or automatic weighing machine to a predetermined weight per piece. Further, in the charging step S9, the liquid is naturally dropped into the temporary molding female mold via the hopper. After the charging, in a transporting step S10, the temporarily molded female mold is transported to a temporary molding position, and in a next temporary molding step S11, the friction material is pressurized by a hydraulic press to be temporarily molded. Alternatively, in the back metal integrated temporary molding step S12, the friction material in the temporary molded female mold transported to the temporary molding position and the adhesive-coated back metal attracted by the magnet to the temporary molded upper mold and transported to the same position are transferred. It is pressurized and integrally molded.

Then, in the next thermoforming step S13, the frictional material of the temporary molding taken out and conveyed from the temporary molding female mold is adsorbed to the temporary molding upper mold by a magnet immediately before the step S13. After supplying the backing metal coated with the adhesive which has been conveyed, the friction material and the backing metal are supplied for 100 to 250.
It is put into a thermoforming female mold heated to ° C., and pressurization and heating are simultaneously performed while supplying heat from a heater. At this time, the friction material is pressed and heated for about 4 to 5 minutes while the gas release operation for releasing the pressure is repeated several times, and the friction material is simultaneously joined with the backing metal and the applied adhesive. The basic structure of the friction pad is formed. Alternatively, the frictional material integrally formed with the back metal is similarly treated in the thermoforming step S13 to form the basic structure of the friction pad. Therefore, the back metal-integrated thermoformed friction material is arranged in a special net and loaded on a large-sized cart exclusively for heat treatment, and the heat treatment is awaited. The thermoforming step S1
For 3, a semi-automatic or automatic machine using a multi-cavity mold is usually used.

Next, in a heat treatment step S14, the backing-integrated thermoformed friction material loaded on several large trucks dedicated to heat treatment is put into a large heat treatment furnace, and is heated in an atmosphere at 100 to 200 ° C. for 2 hours.
Heat treatment is performed for about 4 hours. The heat treatment is usually performed by a batch process or a batch type continuous process. Next, in the groove / surface processing step S15, a groove for discharging sludge is formed at the center of the back metal-integrated heat-treated friction material by a cutting machine, and a squeal stop surface is formed at each end.

Next, in a coating step S16, the back metal integrated friction material having been subjected to the groove and surface processing is arranged in a coating net, and both main surfaces and side surfaces are coated by a coating machine. Then, the film is sent to a baking furnace by a conveyor, and after heating and baking the coating in the next baking step S17, it is taken out after a certain cooling time. Next, in a polishing step S18, the rotor contact surface corresponding to the main surface of the friction material is polished to a certain size by a finish polishing machine to finish.

Next, in a stamping step S19, the lot number, material name,
Stamp the certification number etc. on the back metal. Next, the sensor caulking process S
According to 20, a friction sensor for detecting a decrease in the use of the friction material during use is caulked to a backing metal by a caulking machine, and a friction pad is completed. If the friction sensor is not attached, this step is naturally omitted. Finally, a final product inspection is performed in an inspection and box packing step S21, and the decorative box is packed with a friction pad.

[0010]

However, the method for manufacturing such a friction pad for a disc brake has the following disadvantages. First, in the adhesive application step S6, the amount of the adhesive applied to the back metal varies due to spray application, and the adhesive wraps around and adheres to unnecessary portions. In addition, the amount of the adhesive that is not applied to the backing metal increases and drips, and not only the adhesive is wasted, but also a step of removing the adhesive attached to the net is required.

In addition, in the charging step S9, the mixed friction material after the measurement is dropped naturally from the hopper, the shooter or the like into the temporarily formed female mold, so that the friction material spills out of the female mold.
Unevenness occurs in the female mold, resulting in a non-uniform state, resulting in a difference in thickness after thermoforming, and waste of the friction material occurs. Further, even if the weight of the friction material is weighed in consideration of the friction material spilling or unevenness, waste of the friction material occurs.

Further, in the thermoforming step S13, there is a difficulty in handling and positioning of the temporarily formed friction material or the back metal-integrated temporarily formed friction material before the injection into the thermoformed female mold. Defective products are likely to occur due to problems such as peeling of the backing metal from the friction material, and equipment stoppages are likely to occur. Moreover, the back metal-integrated thermoformed friction material cooled to about room temperature while waiting for heating in the next heat treatment step S14,
Heat energy is wasted.

Further, in the heat treatment step S14, since a large heat treatment furnace is used, temperature unevenness occurs partially and the quality of the friction material becomes unstable. In addition, since the processing is performed for a long time of 2 to 4 hours, the burden required for operation management and quality control increases.
Further, in the groove and surface processing step S15, cutting powder is generated by the cutting process for forming the friction material into a predetermined shape, but material waste of the friction material occurs, and the work environment is deteriorated and the burden on the auxiliary equipment such as a dust collector is increased. I do.

Further, in the polishing step S18, a polishing margin for finishing to a certain size wastes the friction material. Moreover,
The polishing powder generated by the polishing process also deteriorates the working environment and increases the burden on auxiliary equipment such as a dust collector.

The present invention has been made in view of such a conventional problem, and makes effective use of heat energy.
It is an object of the present invention to provide a method of manufacturing a friction pad for a disc brake, in which the time required for heat molding is reduced, material waste of the friction material is small, and the quality is stable.

[0016]

In order to achieve the above-mentioned object, a method of manufacturing a friction pad for a disc brake according to the present invention includes the steps of temporarily mixing a raw material mixture of a friction material in order to manufacture a friction pad made of a back metal integrated friction material. It is put into a molding die, pressurized and temporarily molded, and a step of preheating the temporarily molded friction material together with the temporary molding die is performed. Then, it is preferable to use a Teflon-based resin temporary molding die as the temporary molding die and perform preheating by microwave heating.

Further, a step of transporting the preheated friction material together with the temporary molding die to a thermoforming position, taking out the friction material from the temporary molding die, and putting the friction material into a thermoforming female mold is performed. Also, the friction material in the thermoformed female mold is preheated, an adhesive is applied by a roller, a dried back metal is set, and the friction material and the back metal are joined by the pressure and heat treatment via the adhesive. Then, a step of forming a basic structure of the friction pad made of the back metal integrated friction material is performed.

Further, the friction material is formed into a predetermined shape at the time of thermoforming by the thermoforming female mold. Further, it is preferable to carry out the above-mentioned manufacturing process one by one.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a flowchart showing main manufacturing steps of a friction pad for a disc brake to which the present invention is applied. In producing the friction material, the friction pad for a disc brake first measures the raw material of the friction material in a raw material measuring step P1, for example, and puts it into a mixer in the conventional manner. In the next mixing step P2, mixing is performed by the mixer, for example, in the conventional manner. Then, such a mixed friction material is also stored and stored in a tank for a temporary forming step.

In manufacturing the back metal, the back metal is first punched out in a conventional manner in a press working step P3.
In the next degreasing and cleaning step P4, the back metal is subjected to, for example, conventional degreasing and cleaning. Further, in the next shot blasting step P5, the back metal is subjected to, for example, conventional surface roughening. Then, the back metal that has been degreased and shot blasted is stored in a back metal holder.

In this manner, the mixed friction material and the degreasing
After preparing shot-blasted back metal, weighing process P6
As a result, the mixed friction material stored in the tank is cut out and weighed to a predetermined weight per piece, for example, as in the conventional case. Then, in the next charging step P7, the friction material is charged into a Teflon-based resin temporary forming die by a material scraping-in charging device having rotating blades. Then, the friction material is scraped off and charged, so that the friction material can be evenly and uniformly filled into the temporary forming die. Therefore, it is possible to control the product dimensions such as the degree of parallelism after the heat and pressure molding with high accuracy, reduce the polishing margin, and stabilize the quality. In addition, the friction material is not spilled, and material waste is eliminated. In addition, it takes about 30 seconds to cut out and measure the mixed friction material and put it in by friction.

Next, in a temporary forming step P8, the friction material in the mold is lightly pressed, for example, with a pressing pressure of about 0.5 to 30 kgf / square cm to be formed. At this time, the shape of the temporarily formed friction material and the amount of the friction material can be partially regulated by the lower mold and the upper mold used together with the temporary molding die as needed. Next, in the preheating step P9, the friction material was put together with the temporary molding die by a microwave heating device to 80.
Preheat to ~ 120 ° C. At that time, if a Teflon-based resin mold is used as the temporary molding die, the Teflon-based resin is advantageous because it can heat only the internal friction material in a short time without absorbing microwaves. In addition, this preheating usually results in 240 to 3
The thermoforming time, which takes about 00 seconds, can be greatly reduced, and thermoforming can be performed in a short time. If the friction material is not pressurized during temporary molding, the heat absorption during preheating will be poor, and if the pressure is excessively applied, the friction material will be partially hardened due to the pressure during thermoforming, which will be a later process, and the portion will be too hard. Is easily damaged.

Next, in a conveying step P10, the preheated temporary forming friction material is transferred together with the temporary forming die to the upper part of the thermoforming female mold of the heating press at the thermoforming position. Then, the temporarily formed friction material is taken out of the temporarily formed mold and immediately put into the female mold. At this time, handling, positioning, and the like can be easily performed because the temporary molding die is transported together. Further, the material does not spill when the thermoforming female mold is charged. When the friction material is taken out of the temporary molding die at the temporary molding position and transported to the thermoforming position, the temporary molding friction material expands and cannot enter the thermoformed female mold. Further, even if the friction material is formed in a temporary forming mold to a small size in consideration of swelling due to conveyance, the back metal and the friction material cannot be satisfactorily joined in the gap between the friction material and the mold.

The back metal that has been degreased and shot blasted is taken out of the back metal holder and transported, and in a preheating step P11, the back metal is preheated to 60 to 120 ° C. by a preheating device. Next, in the adhesive application step P12, the preheated back metal is passed over the adhesive application roller of the adhesive roll coater. Then, the adhesive whose specific gravity is controlled can be thinly and uniformly applied to one surface of the back metal. At this time, the adhesive does not flow into unnecessary parts, and the adhesive is not wasted. Next, in a drying step P13, the adhesive applied to the back metal is dried. At this time, since the back metal is preheated, the adhesive can be dried in a short time, and the time for thermoforming can be shortened.

If the adhesive application step is performed by a spray method, it is difficult to adjust the amount of the adhesive applied,
Not only does the waste of the adhesive increase, but there are problems that are difficult to improve, such as the waste of cooling after thermal drying and the difficulty of management. In this regard, when the roller method is used, stable quality of the applied adhesive can be realized only by controlling the specific gravity of the adhesive, periodically cleaning the roller, and the like. In addition, since the coating is performed immediately before the thermoforming, the quality does not deteriorate.

Next, in a thermoforming, groove / face mold forming step P14, immediately before the step P14, the upper part of the thermoformed female mold containing the preheated temporarily formed friction material is preheated, and an adhesive is applied by a roller. The dried backing metal is set, and the friction material and the backing metal are joined by an adhesive using heat and pressure treatment with a heating press device, and then integrally formed and thermoformed. At the same time, sludge is discharged to the center of the friction material by the female mold. Grooves and surface dies are formed, for example, by forming grooves for noise and forming noise suppression surfaces at both ends. Then, in a short time of about 90 to 120 seconds from the preheating of the friction material and the backing metal to the thermoforming, a basic structure of a friction pad for a disc brake made of a backing metal-integrated friction material in which the friction material is formed into a predetermined shape is obtained. Then, such short-time thermoforming doubles the production volume per hour or more. In addition, by forming the grooves and surfaces with a mold, the groove and surface processing steps conventionally performed can be omitted, so that material waste is naturally eliminated.

Next, in a heat treatment step P15, the back metal-integrated thermoformed friction material is sucked by an electromagnet, conveyed to a heat treatment furnace, and put into the furnace while being kept at a high temperature. This heat treatment furnace is a continuous furnace of the conveyor system and its internal temperature is 220 to 270 ° C.
Control to a degree. Then, because of the heat treatment immediately after thermoforming,
There is no need for a heating time or the like, and the quality and performance of the friction material can be stably maintained by a short heat treatment of about 30 minutes. Conventionally, since heat treatment was generally performed by batch processing, the temperature of the back metal-integrated thermoformed friction material often reached room temperature before being brought into the furnace.
It took 4 hours and a long time. Also, for batch processing,
There was a difficult problem in management etc. for maintaining quality stability.

If each of the steps P3 to P15 from the pressing of the back metal and the measurement of one mixed friction material to the heat treatment is performed by an automatic apparatus for the flow process, high-speed production becomes possible. At that time, the back metal is preheated, and the preformed friction material is preheated, and the time from the preheating to the thermoforming integration of the back metal and the friction material and the heat treatment time can be shortened, and the heating and cooling as in the conventional case There is no waste of heat energy such as repeating step several times, and heat energy can be used effectively. In addition, quality can be stabilized by short-term production throughout the year.

Next, in a painting step P16 and a baking step P17, the back metal-integrated heat-treated friction material is painted, for example, in a conventional manner.
Further bake. Next, in a polishing step P18, for example, polishing and finishing are performed in a conventional manner. However, since the dimensions of the product after thermoforming, especially the parallelism, can be controlled with high precision by rubbing in the mixed friction material, the polishing margin is almost zero. There is no waste.

Next, in a stamping step P19, the back metal is stamped, for example, in the conventional manner. If it is necessary to mount the friction sensor, the sensor is caulked and attached to the back metal in the next sensor caulking step P20, for example. Then, finally, in an inspection / box packing step P21, for example, a final product inspection is performed as in the conventional case, and the finished friction pad is packed in a decorative box.

In the above embodiment, a case has been described where one kind of friction pad for a disc brake is manufactured by using one set of automatic apparatus in a single-running process. Since furnaces and the like have a large processing capacity, by sharing them, it is possible to provide a plurality of sets of automatic devices for the single-flow process and produce a plurality of types, for example, two types of friction pads for disc brakes in parallel.

[0032]

According to the present invention described above, claim 1
In the described invention, by using the temporary forming mold for the temporary forming of the mixed friction material, it is possible to perform the subsequent pre-heating treatment and the like for the friction material which has been put into the temporary forming mold and temporarily formed, with respect to the temporary forming mold. It will be convenient. By preheating the temporarily formed friction material together with the temporarily formed mold, the time from preheating to thermoforming and the heat treatment time can be reduced. Therefore, the heat molding time can be shortened by effectively utilizing the heat energy, and the quality can be stabilized. Further, in the invention according to claim 2, by using a temporary molding die made of a Teflon-based resin and performing preheating on the temporarily-formed friction material by microwave heating, the Teflon-based resin does not absorb the microwave and only the internal friction material is absorbed. This is advantageous because heating can be performed uniformly in a short time. Therefore, the time from preheating to thermoforming and the heat treatment time can be greatly reduced.

According to the third aspect of the present invention, the preheated preformed friction material is transported together with the preformed mold to the thermoforming position, taken out of the preformed mold, and introduced into a thermoformed female mold, thereby improving handling and handling. Positioning and the like can be easily performed. or,
According to the invention as set forth in claim 4, by preheating the back metal used in the thermoforming of the temporarily formed friction material in advance, it is possible to promote the drying of the adhesive applied to the back metal by a roller. The thermoforming time of the back metal-integrated friction material joined and integrated via an adhesive can be greatly reduced, and productivity can be improved. Moreover, when the adhesive is applied to the back metal by a roller, the adhesive can be applied uniformly and stably.
In addition, the adhesive does not sneak into unnecessary parts, and the waste of the adhesive can be eliminated.

According to the fifth aspect of the present invention, by forming the friction material into a predetermined shape at the time of thermoforming by the thermoforming female mold, a predetermined shape processing step in the post-process for the friction material can be omitted. Naturally, there is no material waste of the friction material as compared with the case where the processing step is performed. Further, in the invention according to claim 6, the quality can be stabilized by making the manufacturing process a single flow process.

[Brief description of the drawings]

FIG. 1 is a flowchart showing main manufacturing steps of a friction pad for a disc brake to which the present invention is applied.

FIG. 2 is a flowchart showing main manufacturing steps of a conventional friction pad for a disc brake.

[Explanation of symbols]

P1: Friction material raw material measurement process P2: Raw material mixing process
P3: Back metal pressing process P4: Back metal degreasing cleaning process
P5: Back metal shot blasting process P6: Friction material single weighing process P7: Friction material temporary forming die charging process P8 ... Friction material temporary forming process P9 ... Friction material preheating process P10 ... Friction material transporting process P11 ... Back metal preheating process P12: Back metal bonding Agent application process P13: Back metal drying process P14: Back metal integrated friction material thermoforming, groove / face mold forming process P15: Back metal integrated friction material heat treatment process P16 ... Back metal integrated friction material coating process P1
7: Back metal integrated friction material baking process P18: Back metal integrated friction material polishing process P19: Back metal integrated friction material stamping process P20 ...
Back metal integrated friction material sensor caulking process P21… Back metal integrated friction material (friction pad) inspection / boxing process

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F16D 69/00 F16D 69/00 R // B29L 31:16 B29L 31:16 F term (reference) 3J058 BA61 BA63 CA41 CA47 EA33 EA37 GA64 GA65 GA68 GA92 GA95 4F201 AH81 AJ03 BA03 BA04 BC01 BC12 BC21 BD10 BM07 BN10 4F211 AH81 AJ03 TN26 TN60

Claims (6)

[Claims] In a method of manufacturing a friction pad for a disc brake comprising a back metal integrated friction material, a raw material mixture of the friction material is charged into a temporary molding die, and is temporarily molded by pressurizing. A method of manufacturing a friction pad for a disc brake, comprising preheating a molding die. 2. The method for producing a friction pad for a disc brake according to claim 1, wherein a preforming is performed by microwave heating using a temporary forming die made of a Teflon resin as the temporary forming die. 3. The pre-heated preformed friction material is transported to a thermoforming position together with the preformed mold, and the friction material is taken out of the preformed mold and put into a thermoforming female mold. Or a method for producing a friction pad for a disc brake according to the above item 2. 4. The friction material in the thermoforming female mold is preheated, an adhesive is applied by a roller, a dried back metal is set, and the friction material and the back metal are bonded by pressure and heat treatment. 4. The method for manufacturing a friction pad for a disc brake according to claim 3, wherein the friction pad is made of a friction material integrally formed with the back metal to form a basic structure of the friction pad. 5. The method for manufacturing a friction pad for a disc brake according to claim 4, wherein the friction material is formed into a predetermined shape by the thermoforming female mold during thermoforming. 6. The method for manufacturing a friction pad for a disc brake according to claim 4, wherein said manufacturing step is performed by a single flow step.