JP2017194082A - Process of manufacture of disc brake pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process of manufacture of a disc brake pad of which waste amount can be reduced.SOLUTION: This invention relates to a process of manufacture comprising a preliminary molding step for charging raw material composed of friction member composition in a cavity formed by a lower part die and a die hole of an upper die forming an outer peripheral shape of the friction member, lowering a second forming die for molding a concave part formed at an upper end surface of the friction member, flowing in advance raw material of which volume corresponds to a volume of the concave part formed by a second die, then lowering a first molding die for molding a convex part formed at an upper end surface of the friction member and at the same time lowering the second molding die to thermo-press and mold the raw material to perform a preliminary molding and to attain a preliminary molded body having irregularities at the upper end surface; thermo-press molding to perform a thermo-press molding by using the molding die for thermo-press molding operation having irregularities corresponding to positions of the irregularities of the preliminary molding body at the molding surface to attain the thermo-press molding body with irregularities at the upper end surface; and machining for machining the upper end surface of the thermo-press molded body having irregularities at the upper end surface.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a disc brake pad used for braking of automobiles, motorcycles and the like, and in particular, a friction material made of a friction material composition including a fiber base material, a binder, an organic filler, and an inorganic filler, The present invention relates to a disc brake pad fixed to a back plate (back metal) directly through a back plate or an intermediate layer.

  Disc brake pads used for braking automobiles, motorcycles, etc. are housed in calipers and generate frictional force by holding and pressing the sides of the disc rotor that rotates with the axle with hydraulic pressure to convert kinetic energy into thermal energy. As shown in FIG. 1, a structure in which a friction material 2 for friction sliding with a disk rotor is directly laminated on a back plate (back metal) 1 attached to a caliper, or a friction material, as shown in FIG. 2 is laminated through an intermediate layer 3 that is bonded.

  The disc brake pad is filled with a friction material composition including a fiber base material, a binder, an organic filler and an inorganic filler in a mold hole of the mold, and the filled friction material composition is pressed to be preformed, After the obtained preform is integrated with the back plate 1 by hot pressing, heat treatment is performed as necessary to cure the binder, and grinding of the upper end surface 2a of the friction material 2 and the chamfer 2b, It is manufactured through machining such as cutting of the slit 2c (Patent Document 1, etc.). In the case of the disc brake pad having the intermediate layer 3, the friction material composition is laminated and filled on the composition forming the intermediate layer, and the friction material composition and the intermediate layer composition are preformed. Can do. In the disc brake pad having the intermediate layer 3, the friction material 2 may be referred to as an upper material and the intermediate layer 3 may be referred to as an under material.

JP-A-9-136255

  In the disc brake pad manufacturing method, as described above, the upper end surface 2a of the friction material 2 is manufactured by being machined by grinding or the like. Therefore, it cannot be reused and must be discarded, and the cost for disposal is required. Therefore, if the amount of disposal can be reduced, the cost for disposal is reduced accordingly, and the disc brake pad can be manufactured at a low cost. Accordingly, an object of the present invention is to provide a disc brake pad manufacturing method that can reduce the amount of waste.

  In order to achieve the above-mentioned object, the present inventors later machined and flattened to form an unevenness on the friction material upper end surface, which becomes a friction surface, and removes only the convex portion of the friction material upper end surface by machining. In this case, it was considered that the amount of waste can be reduced by the amount of the recess on the upper end surface of the friction material. However, in the preliminary molding step and the hot-pressure molding step, when molding is performed with a molding die having a concavo-convex shape on the molding surface and a hot-pressure molding die, the compression ratio differs between the concave portion and the convex portion provided on the molding surface. A friction material with uniform density cannot be obtained. For this reason, the inventors of the present invention have made extensive studies on a method for producing a friction material having a relatively uniform density while forming irregularities on the upper end surface, thereby accomplishing the present invention.

  The disc brake pad manufacturing method of the present invention that achieves the above object includes a lower mold, an upper mold having a mold hole that forms the outer peripheral shape of the friction member, and a convex portion formed on the upper end surface of the friction member. Formed by a lower mold and a mold hole of an upper mold using a mold apparatus comprising a first mold for molding and a second mold for molding a recess formed on the upper end surface of the friction member. The cavity is filled with the raw material made of the friction member composition, and the volume of the recess formed by the second mold is lowered by lowering the second mold for forming the recess formed on the upper end surface of the friction member. The raw material corresponding to the minute is preliminarily flowed to the surroundings, and then the first molding die for molding the convex portion formed on the upper end surface of the friction member is lowered and the second molding die is lowered to hot-press the raw material. And then preform it on the top surface A preforming step for obtaining a preform having projections, and hot pressing using the hot-press molding mold having projections and depressions corresponding to the positions of the projections and depressions on the molding surface, and irregularities on the upper end surface. A hot-pressure forming step for obtaining a hot-pressure formed body having a surface and a machining step for machining the upper end surface of the hot-pressure formed body having irregularities on the upper end surface.

  In the above-described disc brake pad manufacturing method, in the preliminary forming step, the first forming die for forming the convex portion formed on the upper end surface of the friction member is lowered, and the second forming die and the first forming die are lowered. It is preferable that the first mold and the second mold are lowered synchronously after the unevenness of the mold is matched at a predetermined position, and preliminary molding is performed. It is preferable that the unevenness formed on the molding surface of the molding die for pressure molding is formed at a height that is equal as the compression ratio of the hot-press molded body.

  In the disc brake pad manufacturing method of the present invention, irregularities are formed on the upper end surface that becomes the friction material, the friction material is made to have a relatively uniform density, and only the convex portions on the upper end surface of the friction material are removed by machining. Therefore, it is possible to reduce the amount of waste due to the machining of the friction material, and the production cost can be reduced correspondingly.

1A and 1B are schematic views showing the shape of a disc brake pad, FIG. 1A is a top view, and FIG. 1B is a view of FIG. 1A in the case where a friction material is directly laminated on a back plate. FIG. 1C is a schematic diagram showing the AA cross section, and FIG. 1C is a schematic diagram showing the AA cross section of FIG. 1A when the friction material is laminated on the back plate via an intermediate layer. It is. It is a schematic diagram which shows the structure of a metal mold apparatus and the filling process of a friction material composition in the manufacturing method of the disc brake pad of this invention. It is a schematic diagram which shows the state which lowered the 2nd shaping | molding die in the preforming process of the friction material composition in the manufacturing method of the disc brake pad of this invention. In the method of manufacturing a disc brake pad according to the present invention, in the preliminary molding step of the friction material composition, the first molding die is lowered to match the profiles of the lower end surfaces of the first molding die and the second molding die. It is a schematic diagram shown. FIG. 5 is a schematic view showing a state in which the friction material composition is preformed by lowering the first molding die and the second molding die in synchronization in the friction material composition preforming step in the disc brake pad manufacturing method of the present invention. FIG. It is a schematic diagram which shows the hot-pressure shaping | molding process in the manufacturing method of the disc brake pad of this invention. It is a schematic diagram which shows the machining part in the manufacturing method of the disc brake pad of this invention.

  The method for manufacturing the disc brake pad of the present invention will be described below.

  As shown in FIG. 2, a lower mold 11 for forming the lower end surface of the friction member, an upper mold 12 having a mold hole 12a for forming the outer peripheral shape of the friction member, and a convex formed on the upper end surface of the friction member. A mold apparatus is prepared which includes a first mold 13a for molding the part and a second mold 13b for molding a recess formed on the upper end surface of the friction member. That is, the molding die 13 includes a first molding die 13a and a second molding die 13b. Here, the lower end surface of the 1st shaping | molding die 13a and the lower end surface of the 2nd shaping | molding die 13b are formed in the profile which connects smoothly.

  First, the second molding die 13b for molding the recess formed on the upper end surface of the friction member is lowered, and as shown in FIG. 2 Flow around the mold 13b (in the direction of the arrow in the figure). Next, as shown in FIG. 4, the first molding die 13 a that molds the convex portion formed on the upper end surface of the friction member is lowered, and the profile of the lower end surface of the first molding die is lowered in advance. 2 Match the profile of the lower end surface of the molding die 13b, and then, as shown in FIG. 5, the first molding die 13a and the second molding die 13b are lowered synchronously to preliminarily mold the friction material composition M. Do. The preformed preform P has irregularities on the upper end surface, but after the volume of the friction material composition M corresponding to the concave portion of the friction material is previously flowed around the second molding die 13b. Since the preforming is performed, the density distribution of the preform P is relatively uniform.

  Hot press molding is performed using the obtained preform P. As shown in FIG. 6, the hot pressing is performed by inserting the preform P into a cavity formed by the mold hole 22 a of the hot pressing mold 22 and the thermoforming mold 23, and the back plate 1. Laminated on the pre-formed body P, and heat-pressed by heating the pre-formed body P with a hot-pressure forming mold 22 and a thermo-forming mold 23 to obtain a thermo-formed body T, Integration of the hot-pressed product and the back plate. The end surface of the thermoforming mold 23 is formed with a concave portion 23a and a convex portion 23b. The concave portion 23a of the thermoforming mold 23 is formed on the convex portion P2 of the preform P, and the concave portion of the thermoforming mold 23 is formed. 22b is formed in the position corresponding to the convex part P1 of the preform P, respectively. At this time, it is preferable to form the profile of the concave portion 23a and the convex portion 23b of the thermoforming mold so that the compression ratios are equal in each of the concave and convex portions formed on the upper end surface of the hot-press molded body T.

  As shown in FIG. 7A, the obtained thermoformed body T has a concave portion Ta and a convex portion Tb formed on the upper end surface. Thereafter, the concave portion Ta and the convex portion Tb, which are above the dotted line portion of FIG. 7A, are removed by machining such as grinding to form a flat friction surface, and the chamfer portion and the groove portion are machined. The disc brake pad shown in FIG. In the machining of the friction surface, the convex portion Ta of the friction material is discarded, but the discard amount can be reduced by the concave portion Tb of the friction material, and the manufacturing cost can be reduced correspondingly.

  The above form is an example in which the unevenness is formed as a waveform, but may be a rectangle, a trapezoid or the like. Further, the above embodiment is an example in which the concave and convex intervals of the molding die 13 and the hot-pressure molding die 23 are arranged at equal intervals. It can also be arranged at equal intervals. Further, the unevenness can be formed in a continuous shape in one direction or can be formed in a patch shape.

  The above is an example of a method for manufacturing a disc brake pad in which a friction material is directly laminated on a back plate. In the filling process, an intermediate is provided between the lower mold 10 and the cavity formed by the mold hole 11a of the upper mold 11. After filling the intermediate layer composition forming the layer, the friction material composition is laminated and filled on the filled intermediate layer composition, and the subsequent process is performed in the same manner as described above, thereby In addition, it is possible to manufacture a disc brake pad in which friction materials are laminated via an intermediate layer.

  In addition, as a composition of a friction material, the conventional friction material composition can be used as it is. That is, as the friction material composition, a friction material composition including a fiber base material, a binder, an organic filler, and an inorganic filler can be used. As the base fiber, glass fiber, carbon fiber, metal fiber, ceramic fiber, rock wool, aramid fiber, acrylic fiber, or the like can be used. The binder is preferably a thermosetting resin that has a phenol skeleton and is difficult to remain as carbon even when thermally deteriorated. For example, a phenol resin or a phenol resin modified with acrylic or various elastomers can be used. As the organic filler, organic powders such as cashew dust and rubber dust can be used. As the inorganic filler, inorganic powder particles such as alumina and zirconia, lubricants such as graphite, antimony sulfide and tin sulfide, and metal powder particles such as copper, aluminum and zinc can be used.

  Moreover, you may add the other process conventionally performed other than said preforming process, a hot-pressure forming process, and a machining process as needed. That is, in the disc brake pad manufacturing method of the present invention, a heat treatment step for promoting the curing of the resin may be provided, a scorch treatment step for scorching the surface of the friction material may be provided, and a disc brake pad coating step. May be added.

  The disc brake pad of the present invention can reduce the amount of material discarded by machining, and can accordingly reduce the disposal cost, and is suitable as a method for manufacturing a disc brake pad used for braking an automobile, a motorcycle, etc. Is something.

DESCRIPTION OF SYMBOLS 1 ... Back plate, 2 ... Friction material, 2a ... Upper end surface of friction material, 2b ... Chamfer of friction material, 2c ... Slit of friction material, 3 ... Intermediate layer,
DESCRIPTION OF SYMBOLS 11 ... Lower mold, 12 ... Upper mold, 12a ... Mold hole of upper mold, 13 ... Mold, 13a ... First mold, 13b ... Second mold,
DESCRIPTION OF SYMBOLS 22 ... Metal mold | die for hot-pressure molding, 22a ... Mold hole of mold for hot-pressure molding, 23 ... Mold for molding, 23a ... Concavity of the mold for thermo-molding, 23b ... Convex of the mold for thermo-molding Part,
P ... preformed body, Pa ... recessed part of preformed body, Pb ... convex part of preformed body,
T: Thermoformed body, Ta: Concavity of thermoformed body, Tb: Convex portion of thermoformed body

Claims (3)

A lower mold, an upper mold having a mold hole that forms the outer peripheral shape of the friction member, a first mold for molding a convex portion formed on the upper end surface of the friction member, and an upper end surface of the friction member. A mold device comprising a second mold for molding the recess
Filling the cavity formed by the lower mold and the mold hole of the upper mold with the raw material made of the friction member composition,
Lowering the second mold for molding the recess formed on the upper end surface of the friction member, and flowing the raw material corresponding to the volume of the recess formed by the second mold in advance to the surroundings,
Next, the first mold for forming the convex portion formed on the upper end surface of the friction member is lowered and the second mold is lowered to perform the hot molding of the raw material to perform the preforming, and the upper end surface is uneven. A preforming step to obtain a preform with
Hot pressing using a hot-pressure forming mold having irregularities corresponding to the positions of the irregularities of the preform on the molding surface, to obtain a hot-pressure molded article having irregularities on the upper end surface; and
A method for manufacturing a disc brake pad, comprising: a machining step of machining a top end surface of a hot-pressed body having irregularities on the top end surface.   In the preliminary molding step, the first mold for molding the convex portion formed on the upper end surface of the friction member is lowered so that the irregularities of the second mold and the first mold coincide with each other at a predetermined position. 2. The method for manufacturing a disc brake pad according to claim 1, wherein the first molding die and the second molding die are lowered synchronously to perform preliminary molding.   2. The unevenness formed on the molding surface of the hot-press molding die in the hot-pressure molding step is formed at a height equal to the compression ratio of the hot-press molded body. 3. A method for producing a disc brake pad according to 2.

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