JP6763688B2 - Disc brake pad molding method - Google Patents

Description

The present invention relates to a method for forming a disc brake pad used for braking a two-wheeled vehicle or a four-wheeled vehicle.

A brake pad 10 used for a disc brake attached to a two-wheeled vehicle or a four-wheeled vehicle generally has a friction member 11 containing a base fiber, an organic binder, and a friction modifier made of a steel plate or the like, as shown in FIG. The one which is overlapped with the back plate 12 and compression-molded is used. In a disc brake, the disc pad 10 is pressed against a rotating metal disc rotor, and the frictional force at that time brakes an automobile or the like. However, the disc pad 10 or the disc rotor vibrates during braking to brake. There is a problem of making a squeal. As a measure for suppressing the occurrence of such squeal during braking, a method of providing a chamfer 11a at the end of the friction member of the disc brake pad 10 is performed as shown in FIG. In addition, there is also a groove portion 11b formed in a substantially vertical direction from the friction surface for removing mud that has infiltrated into the friction surface and wear powder generated by friction from the friction surface.

The chamfered portion 11a and the groove portion 11b of the corner portion of the friction member are generally formed by compression molding the friction member into a plate shape and then performing grinding or cutting. That is, the chamfered portion 11a is formed by removing the corner portion (hatched portion) (see, for example, Patent Document 1 and the like). Further, the groove portion 11b is formed by groove processing from the upper end surface of the friction member.

The chamfered portion 11a is provided by a method in which an inclined surface is provided on a molding die for compression molding a friction member and the chamfered portion 11a is formed by the inclined surface (for example, Patent Documents 2, 3 and the like), and a slit provided on the molding die. A method of forming the groove portion 11b by the portions (for example, Patent Document 3 and the like) has been proposed.

Japanese Unexamined Patent Publication No. 9-136255 Jitsufuku No. 5-26361 Japanese Unexamined Patent Publication No. 2004-324763

In the method described in Patent Document 1 and the like in which a chamfer is formed at an end portion of a friction member by grinding or the like, a processing step for forming the chamfer is required as a separate process, and the processing cost increases. In addition, since the corners are scraped and removed, the raw material is wasted by that amount, and the disposal cost of the polishing powder generated by the grinding process further increases the manufacturing cost.

On the other hand, the method of forming a chamfer at the end of the friction member by the mold for compression molding the friction member described in Patent Documents 2 and 3 and the like does not require a separate step for forming the chamfer. However, when the raw material of the friction member is flatly filled in the molding die and compression molded, the raw material of the friction member contains a large amount of fiber material and has low fluidity, so that the difference in the compression ratio of the raw material between the chamfered portion and the other portion Therefore, the density of the chamfered portion tends to be higher than that of the other portions. In this case, squeal is likely to occur as the friction member wears. In addition, a large in-plane density difference of the friction member may cause damage due to the occurrence of cracks or the like.

Further, when the preformed body obtained by preforming is integrated with the back plate in the subsequent heating and pressurizing step, if the strength of the preformed body is low, it is transferred to the subsequent heating and pressurizing step. There is a risk that the preformed body will be destroyed.

From these facts, the present invention is a method for forming a disc brake pad in which chamfering of a friction member of a disc brake pad is formed by compression molding, and a homogeneous disc having a small density difference between the chamfered portion of the friction member and other portions. It is an object of the present invention to provide a method for forming a brake pad, and to provide a method for forming a disc brake pad capable of obtaining a preformed body that is easy to handle even when the strength of the preformed body is low. The purpose.

The disc brake pad molding method of the present invention forms a lower mold, an upper mold having a mold hole for forming the outer peripheral shape of the friction member, a molding mold for molding the upper end surface of the friction member, and a chamfered portion. Using a mold device consisting of a molding die, the back plate is placed on the lower mold, and the upper mold is placed at a desired position to rub against the die hole of the stamp and the cavity formed by the back plate. The raw material composed of the member composition is filled, and the molding die forming the chamfered portion of the friction member is lowered to allow the raw material corresponding to the body integral of the notch formed by the chamfer to flow to the center in advance, and then flow. The molding die for molding the upper end surface of the friction member is lowered so that the position on the upper surface side of the chamfering surface of the molding die forming the chamfered portion and the position of the molding die surface of the molding die for molding the upper end surface are matched. After that, the molding die for forming the chamfered portion of the friction member and the molding die for forming the upper end surface of the friction member are synchronously lowered to hot-press mold the raw material, and the chamfered portion is formed on one end surface of the back plate. It is characterized in that the friction member is integrally molded.

In the method for molding a disc brake pad of the present invention, a convex portion for forming a groove portion of the friction member can be provided in a molding mold for forming the upper end surface of the friction member, and the convex portion forming the groove portion is provided as described above. It is also possible to provide a convex portion driving means that can be driven independently of the molding die that forms the upper end surface of the friction member.

According to the disc brake pad molding method of the present invention, a processing step of another process is not required, raw materials are not wasted, and the disposal cost of polishing powder is not required, so that the manufacturing cost is reduced. be able to. Further, it is possible to manufacture a uniform disc brake pad in which the difference between the density of the chamfered portion and the density of the other portion is small. Further, even when the strength of the preformed body is low, a preformed body that is easy to handle can be obtained.

It is a schematic view of a typical disc brake pad, (a) is a plan view, and (b) is a side view. The area indicated by the diagonal line is the chamfered portion. It is a schematic diagram explaining the filling state of the raw material in the molding method of the disc brake pad of 1st Embodiment of this invention. It is a schematic diagram explaining the state of pushing into the raw material of the molding mold which forms the chamfered portion of the friction member in the molding method of the disc brake pad of 1st Embodiment of this invention. It is a schematic diagram explaining the descent state of the molding die for molding the upper end surface of a friction member in the method of molding a disc brake pad of the first embodiment of the present invention. It is a schematic diagram explaining the compressed state of a raw material in the molding method of the disc brake pad of 1st Embodiment of this invention. It is a schematic diagram explaining the extracted state of the preformed body in the method of molding the disc brake pad of 1st Embodiment of this invention. It is a schematic diagram explaining the hot pressure molding of a preformed body. It is a schematic diagram explaining the filling state of the raw material in the molding method of the disc brake pad of the 2nd Embodiment of this invention. It is a schematic diagram explaining the state of pushing into the raw material of the molding mold which forms the chamfered portion of the friction member in the molding method of the disc brake pad of the 2nd Embodiment of this invention. It is a schematic diagram explaining the descent state of the molding die for molding the upper end surface of a friction member in the method of molding a disc brake pad of the second embodiment of the present invention. It is a schematic diagram explaining the compressed state of the raw material in the molding method of the disc brake pad of the 2nd Embodiment of this invention. It is a schematic diagram explaining the extracted state of the preformed body in the method of molding the disc brake pad of the 2nd Embodiment of this invention.

[Method for molding disc brake pads according to the first embodiment]
The method of molding the disc brake pad according to the first embodiment of the present invention will be described with reference to FIGS. 2 to 6. The lower mold 2 is provided with a recess 2a, and the back plate B is housed in the recess 2a. On the lower mold 2 that accommodates the back plate B, an upper mold 1 having a mold hole that forms the outer peripheral shape of the friction member is arranged.

The molding die is composed of a molding die 4 for molding the upper end surface of the friction member and a molding die 3 for molding the chamfered portion of the friction member. The molding die 3 for molding the chamfered portion of the friction member is configured to be driven in the vertical direction independently of the molding die 4 for forming the upper end surface of the friction member by a driving means such as a fluid pressure cylinder. Further, the molding die 4 for forming the upper end surface of the friction member is formed with a convex portion 4a for forming the groove portion 11b of the friction member 11.

In the method for molding a disc brake pad according to the first embodiment of the present invention using such a mold device, as shown in FIG. 2, the raw material M is formed by a back plate B and a mold hole of the upper mold 1. It is charged into the cavity to be filled. The bulkiness of the raw material M at this time is H0.

The raw material M of the friction material is composed of a fiber base material, an organic binder, a friction adjusting material and the like. As the base fiber, glass fiber, carbon fiber, metal fiber, ceramic fiber, rock wool, aramid fiber, acrylic fiber and the like can be used. As the organic binder, a thermosetting resin having a phenol skeleton and which does not easily remain as carbon even after thermal deterioration is preferable. Phenolic resins, acrylics, phenolic resins modified with various elastomers, etc. can be used. As the friction modifier, inorganic powder particles such as alumina and zirconia, metal sulfides such as graphite, antimony sulfide and tin sulfide, and organic powders such as cashew dust and rubber dust can be used.

Next, as shown in FIG. 3, the molding die 3 for forming the chamfered portion of the friction member is lowered into the filled raw material M, and the amount of the raw material M corresponding to the volume of the notch formed by the chamfering is lowered. Is preliminarily flowed to the center in the state of bulky H0 before molding. At this time, the pushing depth H of the molding die 3 for molding the chamfered portion of the friction member is preferably 30 to 50% from the bulky state H0 of the raw material before premolding.

After that, as shown in FIG. 4, the molding die 3 for molding the chamfered portion of the friction member is a molding die 4 for molding the upper end surface of the friction member while maintaining the state of being pushed into the raw material M at the pushing depth H. The molding die 4 for molding the upper end surface of the friction member is lowered until the height of the lower end surface matches the height of the inclined portion end face of the molding die 3 for forming the chamfered portion.

When the height of the lower end surface of the molding die 4 for forming the upper end surface of the friction member and the height of the inclined portion end surface of the molding die 3 for forming the chamfered portion of the friction member match, as shown in FIG. 5, the friction member The molding die 4 for molding the upper end surface and the molding die 3 for molding the chamfered portion are synchronously lowered to perform compression molding of the raw material M to obtain a molded product P. The molded body P is directly molded on the back plate B to obtain an integrated preformed body.

When the compression molding of the raw material M is completed, the molding die 4 for molding the upper end surface of the friction member and the molding die 3 for molding the chamfered portion of the friction member are raised, and the upper mold 1 is moved upward, which is not shown. The preformed body 10'in which the back plate B and the molded body P are integrated is extracted by an extraction means such as an extraction pin.

The molded body P of the preformed body 10'is formed in a molding die 4 in which a corner portion is formed as a chamfered portion 11a by a molding die 3 for molding a chamfered portion of a friction member and an upper end surface of the friction member is molded. The groove portion 11b is formed by the convex portion 4a for forming the groove portion 11b of the friction member 11. Therefore, chamfering for forming the chamfered portion 11a and grooving for forming the grooved portion 11b are not required.

Further, the molding die 3 for forming the chamfered portion of the friction member and the molding die 4 for forming the upper end surface of the friction member are used as described above, and the molding die 4 for forming the upper end surface of the friction member is used as a raw material. By pushing the molding die 3 that forms the chamfered portion of the friction member having an inclined surface deeply into the raw material M without contacting M, the raw material M of the chamfered portion is sufficiently flowed to the center, and then the true raw material. Since M is compression-molded, the difference between the density of the chamfered portion 11a and the density of other portions of the molded body P after molding is small.

Further, the molded body P has a groove portion 11b formed in the central portion as described above, and the molded body P alone may be broken from the groove portion 11b. However, the molded body P is integrated on the back plate B. Since it is molded into the above, it can be handled without fear of breakage from the groove portion 11b, and it becomes easy to carry it to the next step.

The angle of the chamfered portion of the premolding die is preferably the angle of the chamfered portion formed by thermoforming, but if it is 10 ° or more with respect to the horizontal plane of the central portion, the raw material flows sufficiently. The width of the chamfered portion of the premolding die is preferably 80% to 120% of the chamfered width formed by thermoforming, but the width formed by thermoforming is more preferable.

As shown in FIG. 7, the obtained preformed body 10'is heated by the mold holes of the thermoforming mold 7 and the thermoforming mold 8 to be thermoformed, and the thermoformed product is molded into a mold. After being extracted from No. 7, heat treatment, painting, processing, etc. are performed to obtain a disc brake pad as shown in FIG.

[Method for molding disc brake pads according to the second embodiment]
The method of molding the disc brake pad according to the second embodiment of the present invention will be described with reference to FIGS. 8 to 12. In the mold apparatus used in the method for molding the disc brake pad of the first embodiment, the convex portion 4a for forming the groove portion 11b of the friction member 11 is formed on the molding mold 4 for forming the upper end surface of the friction member. Although it is fixedly arranged, the mold device used in the method for molding the disc brake pad of the second embodiment of the present invention includes a fluid pressure cylinder or the like in the mold 4 for molding the upper end surface of the friction member. The difference is that the convex portion driving means 5a is provided so that the convex portion 5 for forming the groove portion 11b of the friction member 11 can be raised and lowered independently of the molding die 4 forming the upper end surface of the friction member.

Further, in the mold apparatus used in the method for molding the disc brake pad of the first embodiment, the back plate B is provided with the back plate B accommodating recess 2a in the lower mold 2. However, in the mold apparatus used in the method for molding the disc brake pad of the first embodiment, the upper end surface of the lower mold 2 is formed as a flat surface, and the back plate is formed on the upper surface of the lower mold 2. B is placed, and the upper mold 1 is provided with a recess 1a to be fitted with the back plate B so that the upper mold 1 is positioned with respect to the back plate B.

Other configurations are the same as the mold apparatus used in the method for molding the disc brake pad of the first embodiment described above.

In the method for molding the disc brake pad of the second embodiment of the present invention using such a mold device, the raw material M is made of the back plate B and the mold hole of the upper mold 1 as in the first embodiment. It is charged into the formed cavity and filled (FIG. 8).

Next, as shown in FIG. 9, the molding die 3 for forming the chamfered portion of the friction member is lowered into the filled raw material M, and the amount of the raw material M corresponding to the volume of the notch formed by the chamfering is lowered. Is previously flowed to the center. At this time, both the convex portion 5 and the molding die 3 for forming the chamfered portion of the friction member are lowered to allow the raw material M in an amount corresponding to the volume integral of the groove portion 11b to flow to other portions.

After that, as in the first embodiment, the molding die 3 for molding the chamfered portion of the friction member is a molding die for molding the upper end surface of the friction member while maintaining the state of being pushed into the raw material M at the pushing depth H. The molding die 4 for molding the upper end surface of the friction member is lowered until the height of the lower end surface of 4 matches the height of the inclined portion end face of the molding die 3 for forming the chamfered portion (FIG. 10). At this time, the molding die 4 for forming the upper end surface of the friction member is lowered while maintaining the state of being pushed into the raw material M also for the convex portion 5.

When the height of the lower end surface of the molding die 4 for forming the upper end surface of the friction member and the height of the inclined portion end surface of the molding die 3 for forming the chamfered portion of the friction member match, as shown in FIG. 11, the friction member The molding die 4 for molding the upper end surface and the molding die 3 for molding the chamfered portion are synchronously lowered to perform compression molding of the raw material M to obtain a molded product P. The molded body P is directly molded on the back plate B to obtain an integrated preformed body. At this time, the convex portion 5 is also lowered in synchronization with the molding die 4 for forming the upper end surface of the friction member to form the groove portion 11b.

When the compression molding of the raw material M is completed, the molding die 4 for molding the upper end surface of the friction member and the molding die 3 for molding the chamfered portion of the friction member are raised and the upper mold 1 is raised as in the first embodiment. Is moved upward, and the preformed body 10'in which the back plate B and the molded body P are integrated is extracted by an extraction means such as an extraction pin (not shown) (FIG. 12).

In the method of forming the disc brake pad of the second embodiment, the convex portion 5 for forming the groove portion 11b can be driven up and down independently of the forming die 4 for forming the upper end surface of the friction member, so that the raw material M Since the amount of the raw material M corresponding to the body integral of the groove portion 11b can be flowed to other portions prior to the compression molding of the above, the density of the obtained friction member can be made more uniform in each portion.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

It was produced under the conditions when the pressing depth T of the mold 1 for forming the chamfered portion of the premolding mold was changed from Examples 1 to 7. A comparative example is one in which there is no chamfered portion (flat) using an integrated mold. The premolded mold of this embodiment uses a chamfered portion with an angle of 24.6 °, a chamfered portion with a width of 11.5 mm, and a central portion with a width of 97 mm, and has a bulky T0 of the friction material raw material M. It was made to be 60 mm.

The densities of the chamfered portion and other portions (central portions) of the preformed bodies of the above Examples and Comparative Examples were measured by the Archimedes method. In addition, the squeal occurrence frequency rate (%) of the preformed body of the comparative example and the preformed body relatively equivalent to those of the comparative example was measured in the examples. The results are shown in Table 1.

As shown in Table 1, by setting the pushing depth of the mold for forming the chamfered part of the premolding die to the optimum depth, a uniform disc brake pad with a small density difference between the chamfered part and other parts can be obtained. It can be manufactured, and the same result can be obtained with the occurrence frequency rate of squeal.

The method for manufacturing a disc brake pad of the present invention eliminates the need for a separate processing process, does not waste raw materials, and eliminates the cost of disposing of abrasive powder. Therefore, it is possible to reduce the manufacturing cost. It is also possible to manufacture a uniform disc brake pad with a small difference between the density of the chamfered part and the density of other parts, and the resulting disc brake pad has a small difference in density between the chamfered part and other parts. Since squeal is unlikely to occur even if the friction material wears, it is suitable for a brake pad for a disc brake used for braking a two-wheeled vehicle or a four-wheeled vehicle.

1 ... Upper mold, 2 ... Lower mold 2, 2a ... Recessed part, 3 ... Molding mold for molding the chamfered portion of the friction member, 4 ... Molding mold for molding the upper end surface of the friction member, 4a ... Convex part, 5 ... Convex part, 10 ... Disc pad, 10'... Preformed body, 11 ... Friction member, 11a ... Friction member chamfering, 11b ... Friction member groove, 12 ... Back plate, B ... Back plate, M ... Raw material, P ... Mold

Claims (3)

Using a mold device consisting of a lower mold, an upper mold having a mold hole for forming the outer peripheral shape of the friction member, a molding mold for molding the upper end surface of the friction member, and a molding mold for molding a chamfered portion. ,
The back plate is placed on the lower mold, the upper mold is placed at a desired position, and the cavity formed by the die hole of the stamp and the back plate is filled with the raw material composed of the friction member composition.
The molding mold forming the chamfered portion of the friction member is lowered to a position where the chamfered portion is below the upper surface of the filled raw material and pushed into the raw material, which corresponds to the volume of the notch formed by the chamfering. Preliminarily flow the raw materials to the center side
Next, the molding die for molding the upper end surface of the friction member is lowered to match the position of the upper surface side of the chamfered surface of the molding die forming the chamfered portion with the position of the molding die surface of the molding die for molding the upper end surface. Let me
After that, the molding die for forming the chamfered portion of the friction member and the molding die for forming the upper end surface of the friction member are synchronously lowered to hot-press mold the raw material.
A method for molding a disc brake pad, which comprises integrally molding a friction member having a chamfered portion formed on one end surface of a back plate. The method for molding a disc brake pad according to claim 1, wherein a molding mold for molding the upper end surface of the friction member is provided with a convex portion for forming a groove portion of the friction member. The method for molding a disc brake pad according to claim 2, wherein the convex portion driving means capable of driving the convex portion forming the groove portion independently of the molding die for forming the upper end surface of the friction member is provided.

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