JP6739585B2 - Mold of friction material for brake pad, manufacturing apparatus, manufacturing method and preform - Google Patents

Description

The present invention relates to a friction pad mold for a brake pad, a manufacturing apparatus, a manufacturing method, a preform, and a brake pad.

The brake pad is provided with chamfered portions (sometimes referred to as chamfer portions) at both ends for the purpose of preventing noise during braking (see, for example, Patent Document 1). The friction material of the brake pad is usually designed so that the physical properties such as hardness and density are substantially uniform (for example, see Patent Documents 2-4).

JP, 2011-132991, A JP, 2006-83978, A JP, 2011-127710, A JP, 2011-158006, A

Squeaking during braking of the brake pad tends to occur when the hardness and density of the friction material at both ends are higher than at the center. However, when the powder material is put into the mold for compression molding, the part of the powder material put into the mold that comes into contact with the mold is relatively susceptible to compressive force and heat. The hardness and density of the friction material in the central portion tend to be relatively higher than those in the central portion.

The present invention has been made in view of such a problem, and a mold for a friction material for a brake pad that optimizes the physical properties of the friction material at both ends of the brake pad, a manufacturing apparatus, a manufacturing method, a preform, and An object is to provide a brake pad.

The present invention, in order to solve the above problems, the pressing surface of the mold for pressing and molding the powder material of the friction material for the brake pad, the concave shape that gradually dents from both end sides of the pressing surface toward the center side I made a face.

Specifically, a mold of a friction material for a brake pad, which is fitted to a mold into which the powder material of the friction material for the brake pad is put, and a mold member of the mold member on the surface of the mold member. A pressing surface that forms a region that comes into contact with the powdered material that is thrown in, and that has a concave pressing surface that gradually dents from both end sides of the pressing surface toward the center side.

The friction material of the brake pad is usually heat-pressed while being pressed by the pressing surface after preforming the powder material of the friction material. Since the powder material after preforming is almost in a solidified state, the fluidity is lost. On the other hand, the powder material before press molding can flow according to the shape of the pressing surface of the mold.

Then, the said metal mold|die is a metal mold|die which presses and shape|molds powder material, and is equipped with the metal mold member fitted in the mold into which powder material is put. In addition, a pressing surface for pressing the powder material is provided in a region of the surface of the mold member that comes into contact with the powder material charged into the mold. Since the pressing surface forms a concave surface that gradually dents from both end sides toward the center side, the mold member fits into the mold into which the powder material before the loss of fluidity is put. When the pressing surface presses the powder material, the powder material in the mold flows according to the shape of the pressing surface. As a result, the mold gathers the powder material from both end sides of the pressing surface to the center side, and the surface of the preform that will form the friction surface from the both end sides to the center side. It forms a convex shape that gradually expands as it goes.

The preform molded by the above-mentioned mold is such that the surface that will form the friction surface is formed in a convex shape that gradually swells from both end sides toward the center side, and the powder after preforming Since the material is almost solidified and the fluidity has already been lost, when pressure molding is performed with a mold that forms a flat friction surface, the hardness and density of at least both ends are higher than those of the center part. Hard to get high. Therefore, in the case of the brake pad manufactured from the preform molded by the mold, the physical properties of the friction material at both ends of the brake pad can be optimized.

The pressing surface may be inclined from the portion corresponding to the inner peripheral side of the brake rotor to the portion corresponding to the outer peripheral side of the brake rotor. Since the outer peripheral part of the brake rotor is farther from the axle than the inner peripheral part, the peripheral speed of the outer peripheral part of the brake rotor is higher than that of the inner peripheral part of the brake rotor. And fast. However, if the pressing surface is inclined so as to incline from the portion corresponding to the inner peripheral side of the brake rotor to the portion corresponding to the outer peripheral side of the brake rotor, the mold is a friction surface of the preform. The surface that will be formed is formed so as to gradually expand from the portion corresponding to the inner peripheral side of the brake rotor toward the portion corresponding to the outer peripheral side. When the preform thus formed is pressure-molded with a mold that forms a flat friction surface, at least the density and hardness of the outer peripheral side are less likely to be lower than those of the inner peripheral side. Therefore, the physical properties can be made appropriate according to the peripheral speed of the rotating brake rotor.

Further, the pressing surface may have flat portions at both ends. If both end portions of the pressing surface have flat portions, the chamfered portions of the friction material for the purpose of preventing squeaking and the like have substantially uniform physical properties, so that the chamfered portions are stable in strength.

Further, the present invention can be grasped from the aspect of a manufacturing apparatus. For example, the present invention is a device for manufacturing a friction material for a brake pad, which includes a mold into which the powder material of the friction material for the brake pad is charged, a mold member fitted in the mold, and a mold member. A pressing surface that forms a region of the surface that comes into contact with the powder material that is put into the mold, and has a concave pressing surface that gradually dents from both end sides of the pressing surface toward the center side. A pressing unit that presses the mold member and press-molds the powder material to be put into the mold with the pressing surface.

Further, the present invention can be grasped from the aspect of a manufacturing method. For example, the present invention is a method for manufacturing a friction material for a brake pad, in which a powder material of the friction material for a brake pad is put into a mold in which a mold member is fitted, the mold member is pressed, and the mold is A pressing surface that forms a region of the surface of the member that comes into contact with the powder material that is put into the mold, and is a concave pressing surface that gradually dents from both end sides of the pressing surface toward the center side. Then, the powder material charged into the mold may be pressure-molded.

Further, the present invention can be grasped from the aspect of an intermediate product. For example, the present invention relates to a preform of a friction material for a brake pad, in which a powder material of the friction material for a brake pad is pressure-molded, and a surface of the preform is in contact with a brake rotor. A friction surface forming area for forming a friction surface, and a convex friction surface forming area that gradually swells from both end sides of the friction surface forming area toward the center side. May be.

Further, the present invention can be grasped from the aspect of the final product. For example, the present invention is a brake pad, a thermoformed product obtained by thermoforming a powder material of a friction material for a brake pad, and a friction surface that forms a part of the surface of the thermoformed product and contacts the brake rotor. And the hardness or density of at least both ends of the thermoformed product is not higher than that of the central part.

With the mold, manufacturing apparatus, manufacturing method, preform, and brake pad for the brake pad friction material, it is possible to optimize the physical properties of the friction material at both ends of the brake pad.

It is the 1st example of the figure showing the metallic mold of the friction material for brake pads concerning an embodiment. It is the 2nd example of the figure showing the metallic mold of the friction material for brake pads concerning an embodiment. It is the 1st example of the figure which carried out the polygon display of the shape of the press surface of a metal mold. It is the 2nd example of the figure which carried out the polygon display of the shape of the press surface of a metal mold. It is an example of the figure showing the manufacturing method of the friction material for brake pads using a metal mold. It is the 1st example of the figure showing the manufacturing method of a brake pad. It is the 2nd example of the figure showing the manufacturing method of a brake pad. FIG. 6 is an example of a diagram in which the peripheral speed of the brake rotor sliding on the friction surface of the brake pad is represented by an arrow.

Hereinafter, embodiments of the present invention will be described. The embodiments described below exemplify one aspect of the present invention, and the technical scope of the present invention is not limited to the following aspects.

FIG. 1A is a first example of a diagram showing a mold of a friction material for a brake pad according to an embodiment. The mold 1 is a mold for preforming a friction material of a brake pad applied to a disc brake, and includes a mold member 2 and a pressing surface 3. The mold member 2 is fitted in a mold into which the powder material of the friction material for the brake pad is put. The pressing surface 3 is a surface forming a region of the surface of the mold member 2 that comes into contact with the powder material put into the mold. As shown in the AA cross-sectional view of FIG. 1A, the pressing surface 3 is recessed in a concave shape. One half of the pressing surface 3 is recessed along an arc having an imaginary straight line orthogonal to the AA cross section as an axis. The pressing surface 3 is formed symmetrically. Therefore, the pressing surface 3 forms a concave curved surface that gradually dents from the end portion T side of the pressing surface 3 toward the central portion C side, but from the portion N corresponding to the inner peripheral side of the brake rotor to the brake rotor. It does not tilt toward the portion G corresponding to the outer peripheral side. The pressing surface 3 has flat portions at both ends.

By the way, in FIG. 1A, although the aspect which dents along the circular arc which makes a 2nd virtual straight line orthogonal to the extension line of the center line of the pressing surface 3 into an axis|shaft is taken, the metal mold|die 1 which concerns on this embodiment is It is not limited to such an aspect. FIG. 1B is a second example of a diagram showing a mold of the friction material for a brake pad according to the embodiment. As shown in FIG. 1B, for example, the mold 1 according to the present embodiment has an AA cross section that is inclined by Θ degrees with respect to the center line of the pressing surface 3, and is inclined at such an angle A-. It is also possible to adopt a mode in which it is recessed along an arc whose axis is a second virtual straight line that is orthogonal to the extension of the first virtual straight line that is orthogonal to the A section. Further, the mold 1 according to the present embodiment is arranged along an arc whose axis is a second virtual straight line that is orthogonal to the extension line of the first virtual straight line that is inclined less than Θ degrees with respect to the center line of the pressing surface 3. It is possible to adopt a mode in which it is depressed, or along a circular arc whose axis is a second virtual straight line that is orthogonal to the extension line of the first virtual straight line that is inclined by more than Θ degrees with respect to the center line of the pressing surface 3. It may be possible to adopt a mode in which it is depressed. When the inclination of the first virtual straight line with respect to the center line of the pressing surface 3 is increased, the hardness and density of the portion corresponding to the outer peripheral side of the brake rotor is less likely to be lower than that of the inner peripheral side.

FIG. 2A is a first example of a diagram in which the shape of the pressing surface 3 of the mold 1 is displayed in polygons. The pressing surface 3 forms a concave curved surface that gradually dents from the end portion T side of the pressing surface 3 toward the central portion C side. That is, the pressing surface 3 forms a concave curved surface that gradually dents from the two end portions T side in the longitudinal direction toward the central portion C side, but from the portion N corresponding to the inner peripheral side of the brake rotor to the brake rotor. It does not incline toward the portion G corresponding to the outer peripheral side. The pressing surface 3 has flat portions at both ends.

In addition, the AA cross section is inclined by Θ degrees with respect to the center line of the pressing surface 3, and is orthogonal to the extension line of the first virtual straight line which is orthogonal to the AA cross section inclined at such an angle. When a mode is adopted in which the pressing surface 3 of the die 1 is recessed along an arc having the second virtual straight line as an axis, the pressing surface 3 is as follows. FIG. 2B is a second example of a diagram in which the shape of the pressing surface 3 of the mold 1 is displayed as polygons. When a mode is adopted in which the pressing surface 3 of the mold 1 is recessed along an arc having a second virtual straight line that is orthogonal to the extension of the center line of the pressing surface 3, the pressing surface 3 of the mold 1 is on the end T side of the pressing surface 3. From the central portion C side toward the central portion C side, and further inclined from the portion N corresponding to the inner peripheral side of the brake rotor to the portion G corresponding to the outer peripheral side of the brake rotor. The pressing surface 3 has flat portions at both ends, like the mold 1 shown in FIG. 2A.

Since the pressing surface 3 is formed in this manner in the mold 1 according to the present embodiment, a preform preformed by using the mold 1 has the following form.

FIG. 3 is an example of a diagram showing a method of manufacturing a friction material for a brake pad using the mold 1. When performing preforming using the mold 1, the powder material 5 is put into the mold 4 into which the mold 1 fits (FIG. 3(A)). Next, a press machine (not shown) that sandwiches the powder material 5 put in the mold 4 between the upper mold 6 (mold 1) and the lower mold 7 (which is an example of the “pressing means” in the present application) Press with (Fig. 3(B)). As a result, the preform 8 obtained by pressure-molding the powder material 5 remains in the mold 4 (FIG. 3C). The mold 1 according to the embodiment is not limited to the mode used as the upper mold 6 as shown in FIG. 3, and can be applied as the lower mold 7. When the mold 1 according to the embodiment is applied as the lower mold 7, the upper mold 6 is formed like the lower mold 7 shown in FIG. 3 so that the preform 8 is thermoformed together with the pressure plate and pressure-bonded to the pressure plate. It is preferable that the surface for pressing the powder material 5 is flat.

Since the pressing surface 3 of the die 1 forms a concave curved surface that gradually dents from both end sides toward the center side, the powder material before the fluidity is lost is put into the mold 4. When the pressing surface 3 presses the powder material, the powder material in the mold 4 flows according to the shape of the pressing surface 3. As a result, in the mold 1, the surface of the preform 8 that will form the friction surface is formed in a convex shape that gradually expands from both end sides toward the center side. Further, both end portions where chamfered portions of the friction material are provided for the purpose of preventing squealing etc. are formed flat.

That is, the pressing surface 3 of the mold 1 according to the embodiment forms a concave curved surface that gradually dents from the end portion T side of the pressing surface 3 toward the central portion C side, and further from the portion N side. Since the preform 8 is inclined toward the portion G side, the preform 8 forms a preform 8 obtained by pressure-molding the powder material 5 and a friction surface of the surface of the preform 8 that comes into contact with the brake rotor. The frictional surface forming area 9 is provided with a convex frictional surface forming area 9 that gradually expands from both end sides of the frictional surface forming area 9 toward the central portion side. The preform 8 is thermoformed while being pressed together with the pressure plate, and the following brake pads are formed through the usual steps of heating, polishing, surface baking, painting, and the like.

FIG. 4A is a first example of a diagram showing a method for manufacturing a brake pad. When performing preforming using the preform 8, the pressure plate 13 is placed on the mold 10 in which the preform 8 is fitted (FIG. 4A(A)). Next, the preform 8 fitted in the mold 10 is pressed by the press machine so that the lower mold 11 presses the pressure plate 13 (FIG. 4A(B)). It is assumed that the mold 10 and the lower mold 11 are heated by a heater. Further, the pressing surface 12 of the lower mold 11 for pressing the preform 8 is flat. When the preform 8 fitted in the mold 10 is pressed by the lower die 11 against the pressure plate 13 by a press machine, the thermoformed friction material 15 is pressed against the pressure plate 13 and the brake pad 14 is completed. (FIG. 4A(C)). The friction material 15 thermoformed from the preform 8 has the following physical properties.

The friction material 15 is thermoformed from a preform 8 having a convex friction surface forming region 9 that gradually swells from both ends toward the center. Then, the powder material forming the friction material 15 is in a substantially solidified state by preforming, and the fluidity is lost. Therefore, the friction material 15 thermoformed from the preform 8 is less likely to have hardness or density higher than that of the central portion at least at both ends. Further, since the friction material 15 is formed by thermoforming the preform 8 having flat end portions, both end portions where chamfered portions are formed for the purpose of preventing squealing or the like have hardness or density. It exhibits substantially uniform physical properties, and the chamfered portion is stable in strength even when chamfered.

When the mold 1 shown in FIG. 2B is used, the friction surface forming area 9 of the preform 8 is a portion G side corresponding to the outer peripheral side of the brake rotor to a portion N corresponding to the inner peripheral side of the brake rotor. It will be inclined toward the side. In other words, the preform 8 has a thicker portion in the vicinity of the central portion and the outer peripheral side of the brake rotor, and has a thinner portion in the vicinity of both end portions and the inner peripheral side of the brake rotor. The friction material 15 thermoformed from the preform 8 has the following physical properties.

That is, when the mold 1 shown in FIG. 2B is used, the friction material 15 gradually rises from the portion N side corresponding to the inner peripheral side of the brake rotor to the portion G side corresponding to the outer peripheral side of the brake rotor. Since the preformed material 8 is thermoformed, the friction material 15 thermoformed from the preformed material 8 is less likely to have a lower density or hardness on the outer peripheral side than on the inner peripheral side.

The chamfered portion of the friction material 15 may be formed by grinding after heat treatment such as thermoforming and heating. For example, both end portions of the pressing surface 12 of the lower die 11 are raised to form an oblique inclination. You may keep it. FIG. 4B is a second example of the diagram showing the method for manufacturing the brake pad. If both ends of the pressing surface 12 of the lower mold 11 are raised and provided with an oblique inclination, both ends of the friction material 15 can be chamfered simultaneously with thermoforming, as shown in FIG. 4B.

FIG. 5 is an example of a diagram in which the peripheral speed of the brake rotor sliding on the friction surface of the brake pad is represented by an arrow. The peripheral speed of the brake rotor sliding on the friction surface of the brake pad is not uniform in the friction surface. For example, a brake rotor of a disc brake has a peripheral speed on the outer peripheral side faster than a peripheral speed on the inner peripheral side. Therefore, the wear of the friction material is more likely to proceed in the portion corresponding to the outer peripheral side of the brake rotor than in the portion corresponding to the inner peripheral side. However, in the case of the friction material 15 thermoformed from the preform 8 made by the mold 1 shown in FIG. 2B, the hardness and density at both ends are less likely to be higher than the central part, and at least the density and hardness at the outer peripheral side are high. Is less likely to be lower than that on the inner peripheral side, so that wear of the friction material progresses more uniformly and physical properties of the friction material optimized according to the peripheral speed of the rotating brake rotor are realized. ..

1・・Mold: 2・・Mold member: 3・・Pressing surface: 4・・Form: 5・・Powder material: 6・・Upper mold: 7・・Lower mold: 8・・Preform : 9・・Friction surface forming area: 10・・Form: 11・・Lower mold: 12・・Pressing surface: 13・・Pressure plate: 14・・Brake pad: 15・・Friction material

Claims (4)

Two mold members fitted into a mold into which the powder material of the friction material for the brake pad is put,
A pressing surface of one of the mold members, which forms a region of the surface of the mold member that comes into contact with the powder material charged into the mold frame, and both ends of the pressing surface. A first pressing surface of a concave curved surface that gradually dents along an arc from the side of the part toward the side of the center;
A flat surface that is a pressing surface of the other mold member of the mold members that faces the first pressing surface and that forms a region where the friction material molded by the mold member comes into contact with the pressure plate. A second pressing surface,
Mold of friction material for brake pads. A form into which the powder material of the friction material for the brake pad is put,
Two mold members fitted into the mold,
A pressing surface of one of the mold members, which forms a region of the surface of the mold member that comes into contact with the powder material to be put into the mold , and both ends of the pressing surface. A third pressing surface of a concave curved surface that gradually dents along an arc from the side of the part toward the side of the center,
A flat surface that is a pressing surface of the other mold member of the mold members that faces the third pressing surface and that forms a region where the friction material molded by the mold member comes into contact with the pressure plate. A fourth pressing surface,
Equipment for manufacturing friction materials for brake pads. Put the powder material of the friction material for the brake pad into the mold where the two mold members fit,
A pressing surface of one of the mold members, which presses the mold member and forms a region of the surface of the mold member that comes into contact with the powder material charged into the mold. There is a fifth pressing surface of a concave curved surface that gradually dents along an arc from both end sides of the pressing surface toward the center side, and the other of the mold members facing the fifth pressing surface . The flat sixth pressing surface that is a pressing surface of the mold member and forms a region where the friction material molded by the mold member comes into contact with the pressure plate, and the powder material to be put into the mold. Pressure molding,
Manufacturing method of friction material for brake pad. A preform obtained by pressure molding a powder material of a friction material for a brake pad,
Of the surface of the preform, it is a friction surface forming region that forms a friction surface that comes into contact with the brake rotor, and gradually extends along an arc from both end sides of the friction surface forming region toward the center side. A friction surface forming region of a convex curved surface that swells to
A flat area on the opposite side of the friction surface forming area, which will come into contact with the pressure plate.
Preform of friction material for brake pads.

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