Disk brake

Abstract

A disk brake has a flange portion formed on the outer periphery of a portion of a caliper body main body where an opening is formed. The opening is used for insertion of a cutting tool for machining of a cylinder bore. The outer diameter of the flange portion is larger than that of a general surface of the outer peripheral wall of the bore formed in the caliper body main body. A lid member is secured to the opening by friction stir welding. The flange portion ensures a sufficient welding margin. The overall weight of the disk brake is reduced by minimizing the wall thickness of the general surface of the outer peripheral wall of the bore.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a disk brake according to a first embodiment of the present invention.

FIG. 2 is a sectional view corresponding to the section A-A in FIG. 1, showing the first embodiment.

FIG. 3 is a rear view of a caliper body, showing the first embodiment.

FIG. 4 is a top view of the caliper body, showing the first embodiment.

FIG. 5 is a bottom view of the caliper body, showing the first embodiment.

FIG. 6 is a side view of the caliper body, showing the first embodiment.

FIG. 7 is a perspective view of a caliper body, showing the first embodiment.

FIG. 8 is a rear view of the caliper body, showing the first embodiment.

FIG. 9 is a sectional view showing the way in which lid members are attached to the caliper body in the first embodiment.

FIG. 10 is an enlarged view of part C in FIG. 9, showing the first embodiment.

FIG. 11 is a perspective view of one block of a casting die for producing the caliper body of the first embodiment.

FIG. 12 is a perspective view of the other block of the casting die for producing the caliper body of the first embodiment.

FIG. 13 is a sectional view similar to FIG. 2, showing a second embodiment of the present invention.

FIG. 14 is an enlarged view of part D in FIG. 13, showing the second embodiment.

FIG. 15 is a rear view of a caliper body, showing a third embodiment of the present invention.

FIG. 16 is a sectional view of the caliper body corresponding to the section E-E in FIG. 15, showing the third embodiment.

FIG. 17 is a sectional view showing the way in which lid members are attached to the caliper body in the third embodiment.

FIG. 18 is a sectional view of a caliper body, showing a fourth embodiment of the present invention.

Claims

1. A disk brake adapted to press a brake pad against a disk with a piston that slides in a bore of a cylinder in response to a fluid pressure, said cylinder comprising: a cylinder body having an opening at a bottom thereof; anda lid member that closes said opening;wherein an outer diameter of an outer peripheral surface of a portion at the bottom of said cylinder body where said opening is formed is larger than an outer diameter of a minimum outer diameter portion of an outer peripheral wall of said bore of said cylinder body.

2. A disk brake according to claim 1, wherein a chamfer is formed on the outer peripheral surface of the portion of said cylinder body where said opening is formed, said chamfer narrowing toward an end surface of said cylinder body.

3. A disk brake according to claim 1, wherein a brake caliper having said cylinder body is formed so that a parting line of a casting die extends substantially perpendicular to a plane containing a rotational direction of said disk.

4. A disk brake according to claim 1, wherein the outer peripheral surface of the portion of said cylinder body where said opening is formed and the minimum outer diameter portion of the outer peripheral wall of said bore are connected to each other by a slant surface that gradually increases in diameter toward an end surface of said cylinder body.

5. A disk brake according to claim 4, wherein said slant surface is provided on a region of said outer peripheral wall adjacent to an outer periphery of a surface of the bottom of said cylinder body that borders said bore.

6. A disk brake according to claim 1, wherein said lid member is joined to the opening of said cylinder body by friction stir welding.

7. A disk brake according to claim 6, wherein there are provided a pair of cylinders in which pistons slide in response to a fluid pressure to press against said disk from both sides thereof, said pair of cylinders being connected to each other by a rib extending over an outer peripheral surface of said disk; said opening being provided at a bottom of a cylinder body of one of said pair of cylinders;wherein a radially outwardly projecting bulge portion is provided at a position corresponding to said rib on the outer peripheral surface of the portion of said cylinder body where said opening is formed, said bulge portion being used as a position at which said friction stir welding is completed.

8. A disk brake according to claim 6, wherein a chamfer is formed on the outer peripheral surface of the portion of said cylinder body where said opening is formed, said chamfer narrowing toward an end surface of said cylinder body.

9. A disk brake according to claim 6, wherein a brake caliper having said cylinder body is formed so that a parting line of a casting die extends substantially perpendicular to a plane containing a rotational direction of said disk.

10. A disk brake according to claim 6, wherein the outer peripheral surface of the portion of said cylinder body where said opening is formed and the minimum outer diameter portion of the outer peripheral wall of said bore are connected to each other by a slant surface that gradually increases in diameter toward an end surface of said cylinder body.

11. A disk brake according to claim 10, wherein said slant surface is provided on a region of said outer peripheral wall adjacent to an outer periphery of a surface of the bottom of said cylinder body that borders said bore.

12. A disk brake adapted to press a brake pad against a disk with a piston that slides in a bore of a cylinder in response to a fluid pressure, said cylinder comprising: a cylinder body having an opening at a bottom thereof; anda lid member that closes said opening;wherein a small-diameter portion is formed on a region of an outer peripheral surface of said cylinder body that is adjacent to an outer periphery of a portion thereof where said opening is formed, said small-diameter portion having a smaller outer diameter than an outer diameter of an outer peripheral surface of the portion where said opening is formed.

13. A disk brake according to claim 12, wherein a chamfer is formed on the outer peripheral surface of the portion of said cylinder body where said opening is formed, said chamfer narrowing toward an end surface of said cylinder body.

14. A disk brake according to claim 12, wherein a brake caliper having said cylinder body is formed so that a parting line of a casting die extends substantially perpendicular to a plane containing a rotational direction of said disk.

15. A disk brake according to claim 12, wherein said lid member is joined to the opening of said cylinder body by friction stir welding.

16. A disk brake according to claim 15, wherein there are provided a pair of cylinders in which pistons slide in response to a fluid pressure to press against said disk from both sides thereof, said pair of cylinders being connected to each other by a rib extending over an outer peripheral surface of said disk; said opening being provided at a bottom of a cylinder body of one of said pair of cylinders;wherein a radially outwardly projecting bulge portion is provided at a position corresponding to said rib on the outer peripheral surface of the portion of said cylinder body where said opening is formed, said bulge portion being used as a position at which said friction stir welding is completed.

17. A disk brake according to claim 15, wherein a chamfer is formed on the outer peripheral surface of the portion of said cylinder body where said opening is formed, said chamfer narrowing toward an end surface of said cylinder body.

18. A disk brake according to claim 15, wherein a brake caliper having said cylinder body is formed so that a parting line of a casting die extends substantially perpendicular to a plane containing a rotational direction of said disk.