JP2007071353A - Pad for disk brake and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake pad for a disk brake and the production method therefor which can reduce the swelling part occurring in the edge part of a slit by the scorch processing. <P>SOLUTION: A chamfering 31a, 31b according to the scorch depth by the scorch processing is formed in the edge part of the slit prior to the scorch processing, in the brake pad for the disk brake which performs the scorch processing to a frictional face 22a of the brake pad 15, 16 to form the slit 31 extending to the outer diameter side 15b from the inside diameter side 15a. Here, the chamfering width of the chamfering is desirably set up to 1 to 3 times of the scorch depth and the chamfering angle is desirably set up to 30 to 60 degree. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a disc brake pad that presses a disc rotor and a manufacturing method thereof, and more particularly to a disc brake pad that can suppress a bulging portion generated at an edge portion of a slit by a scorch process and a manufacturing method thereof.

  In general, a disc brake has a disc rotor integrally fixed to the wheel side and a caliper supported on the vehicle body side. The caliper is provided with a pair of brake pads opposed to both sides of the disc rotor. By operating the piston, the pair of brake pads are pressed against the disk rotor, and the disk rotor (wheel) is braked by the frictional force.

In this type of disc brake, for example, as described in Patent Document 1, in order to prevent the squeal that occurs when the brake pad is pressed against the disc rotor by the operation of the piston, the friction surface of the brake pad is used. A slit extending from the inner diameter side of the brake pad toward the outer diameter side is formed.
JP-A-8-49737 (paragraphs 0033 and 0036, FIG. 2)

  Incidentally, although not described in Patent Document 1 described above, in this type of disc brake, the friction surface of the brake pad is used for the purpose of ensuring the effectiveness of the brake when a new brake pad is mounted. In some cases, a heat treatment called scorch is applied. When the scrubbing treatment is applied to the friction surface of the brake pad, the friction surface is deformed and protrudes due to heat, but at this time, particularly the vicinity of the slit, especially the edge portion of the slit is from both the slit processing surface and the pad friction surface. As shown in FIG. 6, the amount of deformation increases, and as shown in FIG. 6, a bulging portion 5 that bulges toward the friction surface 2 is generated at the edge portion 4 of the slit 3 formed in the friction surface 2 of the brake pad 1.

  For this reason, even when the brake is not operated, the bulging portion 5 of the brake pad 1 may come into contact with the disc rotor, which deteriorates fuel consumption due to contact resistance or generates drag torque to wear the disc rotor. Increases and causes brake vibration. Further, local noise between the bulging portion and the disk rotor may cause squeal and abnormal noise.

  In order to eliminate the bulge, it may be possible to cut the bulge after the scorch process, but the process becomes complicated and is not practical. That is, slits are formed on the friction surface of the pad prior to the scorch process, and the friction surface of the pad is finished by machining such as polishing. Therefore, if machining for removing the bulging portion is added after the scorching process, not only two machining operations are required before and after the scorching process, but also a return occurs due to the machining after the scorching process. Further processing is required to remove the return.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a disc brake pad capable of suppressing a bulging portion generated at an edge portion of a slit by a scorch process and a manufacturing method thereof. It is.

  In order to solve the above-mentioned problem, the structural feature of the invention according to claim 1 is that a disc brake pad in which a friction surface of a brake pad formed with a slit extending from an inner diameter side toward an outer diameter side is subjected to scorching treatment. The disc brake pad according to claim 1, wherein chamfering corresponding to a scorch depth by the scorch process is formed at an edge portion of the slit prior to the scorch process.

  The structural feature of the invention according to claim 2 is that in claim 1, the chamfering depth is set to 1 to 3 times the scorch depth, and the chamfering angle is set to 30 to 60 °. This is a disc brake pad.

  A structural feature of the invention according to claim 3 is that a slit extending from the inner diameter side to the outer diameter side is formed on the friction surface of the disc brake pad, and chamfers are formed at both edge portions of the slit. Thereafter, the friction surface of the pad is polished, and then the scrub treatment is performed on the friction surface of the pad.

  According to a fourth aspect of the present invention, there is provided a method of manufacturing a disc brake pad according to the third aspect, wherein the slit and the chamfer are simultaneously formed by machining with a general cutter.

  According to the invention according to claim 1 configured as described above, since the chamfering according to the scorch depth by the scorch process is formed at the edge portion of the slit prior to the scorch process, the friction surface of the brake pad is formed by the scorch process. Although heat is applied from above, a bulge is not generated at the edge of the slit, but the bulge at the edge of the slit can be suppressed by chamfering.

  Therefore, contact with the disc rotor due to the swelling of the brake pad can be avoided, and it is ensured that the contact resistance deteriorates fuel consumption, wear of the disc rotor increases due to drag torque, or abnormal noise is generated. Will be able to prevent.

  According to the invention according to claim 2 configured as described above, the chamfering depth is set to 1 to 3 times the scorch depth, and the chamfering angle is set to 30 to 60 °. It is possible to effectively prevent the occurrence of the bulging portion at the edge portion of the slit due to the scorch process without substantially reducing the effective area of the friction surface.

  According to the invention of claim 3 configured as described above, slits and chamfers are formed on the friction surface of the disc brake pad, and after the friction surface of the pad is polished, the scorch treatment is performed on the friction surface of the pad. Since it was applied, the swelling at the edge of the slit due to the scorch process can be suppressed, and there is no problem of the return of machining that occurs when machining for removing the swollen part is added after the scorch process. Therefore, the surface accuracy of the friction surface is not deteriorated, and additional processing for removing the return is not required.

  According to the invention according to claim 4 configured as described above, since the slit and the chamfer are simultaneously formed by machining with a general cutter, the slit and the chamfer can be easily processed in a short time, and the disk The productivity of brake pads can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a disc brake having a single-piston floating caliper 10. The caliper 10 is disposed on the outer periphery of a disc-like disc rotor 12 that rotates with a wheel. The caliper 10 is supported by a floating bracket (not shown) fixed to the vehicle body side via a slide pin, and includes a cylinder body 13 that can move in the rotational axis direction of the disk rotor 12.

  A bottomed cylindrical piston 14 is fitted to the cylinder body 13 so as to be slidable in the rotational axis direction of the disc rotor 12, and an inner brake pad 15 is disposed at the tip of the piston 14. . The cylinder body 13 is integrally formed with a bridge portion 13 a that straddles the disk rotor 12. Further, a claw portion 13b bent from the distal end portion of the bridge portion 13a is disposed on the outer side of the disc rotor 12, and an outer brake pad 16 is disposed between the claw portion 13b and the disc rotor 12. ing.

  Therefore, when the driver depresses the brake pedal, the brake fluid is supplied to the oil chamber 20 between the center bottom of the cylinder body 13 and the piston 14, and the piston 14 moves to the disc rotor 12 side, and the brake pad 15 on the inner side. The back metal 21 is pressed by the piston 14. As a result, the friction material 22 of the inner brake pad 15 is pressed against the inner peripheral surface of the disk rotor 12.

  On the other hand, when the hydraulic pressure in the oil chamber 20 is increased, the cylinder body 13 is moved in the direction opposite to the moving direction of the piston 14 while being guided by the slide pin due to the pressing reaction force of the piston 14, so that the brake on the outer side The back metal 23 of the pad 16 is pressed toward the disk rotor 12 by the claw portion 13 b of the cylinder body 13. As a result, the friction material 24 of the outer brake pad 16 is pressed against the outer circumferential surface of the disk rotor 12. In this way, the friction members 22 and 24 of the pair of brake pads 15 and 16 are pressed against the peripheral surface of the disk rotor 12 from both sides, and a predetermined braking force is obtained.

  A piston seal 25 made of rubber is provided on the fitting surface between the cylinder body 13 and the piston 14, and the hydraulic pressure of the oil chamber 20 in the cylinder body 13 is held by the piston seal 25, and the brake pads 15, 16. And the disc rotor 10 are adjusted. The brake pads 15 and 16 have the same configuration.

  2 shows details of the brake pad 15 (16). The upper half of FIG. 2 is a view of the brake pad 15 (16) as viewed from the front, and the lower half is the view of the brake pad 15 (16) as viewed from the side. It is a figure. In the figure, a slit 31 having a predetermined depth extending in the radial direction from the inner diameter side 15a to the outer diameter side 15b is formed on the surface (friction surface) 22a of the friction material 22 of the brake pad 15 (16). Chamfers of the same chamfer width corresponding to the depth of material modification of the friction surface 22a of the brake pad 15 (16) by scorch processing (hereinafter referred to simply as scorch depth D1) are provided at both edge portions of 31. 31a and 31b are formed. In addition, the friction surface 22a of the brake pad 15 (16) is polished, and the friction surface 22a is formed to be flush with each other (the same height).

  The friction surface 22a of the brake pad 15 (16) is subjected to scorch processing (heating processing). The scorch depth D1 by scorch processing is usually about 1 to 2 mm. When heat is applied to the friction surface 22a of the brake pad 15 (16) by the scorch process, the brake pad 15 (16) is thermally expanded. Such thermal expansion becomes most noticeable at the edge portion of the slit 31 due to the influence of the thermal action from both the slit 31 and the friction surface 22a, and the bulge portion protruding from the friction surface 22a does not occur at the edge portion of the slit 31. To do. However, in the present embodiment, since chamfers 31a and 31b corresponding to the scorch depth D1 are formed at the edge portion of the slit 31, heat is not locally applied to the edge portion of the slit 31, and the slit 31 It is possible to reduce or eliminate the bulge at the edge portion.

  Next, a method for manufacturing the brake pad 15 (16) will be described with reference to FIG. First, slits 31 having a predetermined depth extending in the radial direction from the inner diameter side 15a toward the outer diameter side 15b are formed by cutting on the friction surface 22a of the brake pad 15 (16), and both edge portions of the slit 31 are formed. Chamfers 31a and 31b are formed by cutting (first step I). The slit 31 and the chamfers 31a and 31b can be efficiently formed by cutting (machining) at the same time using a general cutter. After the slit 31 and the chamfers 31a and 31b are machined on the friction surface 22a of the brake pad 15 (16), the friction surface 22a of the brake pad 15 (16) is finished by polishing (first process II). Thereafter, a scorch process (heating process) is performed on the friction surface 22a of the brake pad 15 (16) (third process III).

  The chamfering width W1 of the chamfers 31a and 31b formed in the edge portion of the slit 31 in the rotation direction (arrow direction in FIG. 2) of the disk rotor 12 is 1 to 3 of the above scorch depth D1 as shown in FIG. For example, when the scorch depth is 1 mm, the chamfer width W1 is set to 1 to 3 mm, and when the scorch depth is 2 mm, the chamfer width W1 is set to 2 to 6 mm. On the other hand, the chamfer angle θ1 of the chamfers 31a and 31b is set to 30 to 60 °. As the chamfering width W1 is larger, the influence of the bulge due to the scorch process can be reduced. However, if the chamfering width W1 is excessively large, the effective area of the friction surfaces 22a and 24a of the brake pad 15 (16) is reduced. Moreover, 1 to 3 times the scorch depth D1 is appropriate.

  In FIG. 2, the chamfering width W1 of the chamfers 31a and 31b is the same as the scorch depth D1, and the chamfering angle θ1 is 45. By forming the chamfers 31a and 31b, heat generated by the scorch process is not locally applied to the edge portion of the slit 31, so that the bulge due to the scorch process can be effectively suppressed, and the bad influence on the friction surface 22a due to the bulge. Can be eliminated. Therefore, contact between the brake pad 15 (16) and the disc rotor 12 is avoided when the brake is not operated and the brake pedal is not operated.

  FIG. 4 shows a second embodiment of the present invention, in which the slit 31A formed in the friction surface 22a of the brake pad 15 (16) is rotated from the inner diameter side toward the outer diameter side in the rotational direction of the disk rotor 10. Is formed so as to extend obliquely along.

  In the second embodiment, by forming the slit 31A obliquely, larger bulges are generated at the edge portions E1 and E2 that form acute angles with respect to the inner diameter side 15a and the outer diameter side 15b. Only small bulges occur at the edge portions E3 and E4 that form an obtuse angle with respect to the side 15c and the outer diameter side 15d. Therefore, in forming the chamfers 31a1 and 31b1, it is effective to form the chamfers 31a1 and 31b1 so that the chamfer widths are continuously different with respect to the extending direction of the slit 31. That is, the chamfers 31a1 and 31b1 are formed so that the edge portions E1 and E2 side have a large chamfering width W1A and the edge portions E3 and E4 side have a small chamfering width W1B. The chamfers 31a1 and 31b1 can be formed simultaneously on both sides by slightly inclining the feeding direction of machining with respect to the slit 31.

  In this case, the chamfers 31a1 and 31b1 may be uniformly formed with the large chamfering width W1A required on the edge portions E1 and E2, and in this way, the slit 31 and the chamfers 31a1 and 31b1 are formed in the first embodiment. As described in the embodiment, it can be formed at a time by machining using a general cutter.

  FIG. 5 shows a third embodiment of the present invention. In order to reduce noise and abnormal noise of the brake pad 15 (16), one edge portion of the slit 31 has a large chamfering width for preventing noise. A chamfer 131a is formed, and a chamfer 31a having a predetermined size according to the scorch depth is formed on the other edge portion. Thus, in the present invention, it is only necessary that a chamfer corresponding to the scorch depth is formed on at least one edge portion of the slit 31, and for example, the chamfer having a chamfer width exceeding 3 times the scorch depth is formed on the other edge portion. It does not prevent the formation of.

  In the above-described embodiment, the example in which the slits 31 and 31A having a predetermined depth are formed on the friction surface 22a of the brake pads 15 and 16 has been described. However, the back metal 21 and 23 are divided into two or three or more. The friction materials 22 and 24 are pasted with a gap corresponding to the slit, and in that state, chamfering is formed at the edge of the slit (gap) and the surface (friction surface) 22a of the friction material 22 and 24 is faced. You may make it grind | polish so that it may become one.

  Note that the simultaneous machining of the slit 31 and the chamfers 31a and 31b by the overall cutter is effective in improving the productivity of the brake pad, but is not necessarily a requirement for the present invention.

1 is a cross-sectional view of a disc brake equipped with a brake pad according to a first embodiment of the present invention. It is a figure which shows the pad for disc brakes in the 1st Embodiment of this invention. It is a figure which shows the manufacturing method of the pad for disc brakes. It is a figure which shows the pad for disc brakes in the 2nd Embodiment of this invention. It is a figure which shows the pad for disc brakes in the 3rd Embodiment of this invention. It is a figure which shows the swelling of the friction surface of the brake pad by the scorch process in the past.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Caliper, 12 ... Disc rotor, 13 ... Cylinder body, 14 ... Piston, 15, 16 ... Brake pad, 21, 23 ... Back metal, 22, 24 ... Friction material, 22a ... Friction surface, 25 ... Piston seal, 31, 31A ... Slit, 31a, 31b, 31a1, 31b1 ... Chamfer, W1, W1A, W1B ... Chamfer width, θ1 ... Chamfer angle.

Claims (4)

In the disc brake pad in which the friction surface (22a) of the brake pad formed with the slits (31, 31A) extending from the inner diameter side (15a) toward the outer diameter side (15b) is subjected to scorch processing, prior to the scorch processing. Then, chamfers (31a, 31b, 31a1, 31b1) corresponding to the scorch depth by the scorch process are formed at the edge of the slit. 2. The disc brake pad according to claim 1, wherein the chamfer width of the chamfer is set to 1 to 3 times the scorch depth, and the chamfer angle is set to 30 to 60 degrees. A slit extending from the inner diameter side to the outer diameter side is formed on the friction surface of the disc brake pad, and chamfers are formed on both edge portions of the slit, and then the friction surface of the pad is polished, A method for manufacturing a disc brake pad, wherein the friction surface of the pad is subjected to a scorch process. 4. The method for manufacturing a disc brake pad according to claim 3, wherein the slit and the chamfer are simultaneously formed by machining with a general cutter.

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