Radial-mount type disc brake

Abstract: A radial-mount type disk brake has a caliper (1) and mounting bolts (3) mounted in bolt holes (2) formed in the caliper (1) with some clearance (t). It is desired to prevent the caliper (1) from turning when braking torque acts thereon due to the clearances (t). The abutment surfaces of the caliper (1) and the mounting member (6) include surfaces (10) perpendicular to the disk axis. By the binding action of the surfaces (10), it is possible to prevent pivoting of the caliper (1).

Description: This invention relates to a radial-mount type disk brake having its caliper fixed stably by improving the way in which the caliper is mounted. A typical radial-mount type disk brake is shown in Figs. 5-7. It has bolt holes 2 formed in the caliper 1 at its disk-leading (when the disk is rotating clockwise) and disk-trailing sides to extend perpendicularly to the disk axis. Mounting bolts 3 are inserted through the bolt holes 2 and threaded into a knuckle 6 to fix the caliper 1 to the knuckle 6. This mounting arrangement provides higher rigidity of the caliper than an ordinary mounting arrangement, in which the caliper 1 is tightened by bolts extending parallel to the disk axis. Such radial-mount type disk brakes are disclosed in unexamined Japanese patent publications 63-135623, 1-210628 and 7-12148. In the radial-mount arrangement, as shown in Fig. 6, clearances t are formed between the bolts 3 and the holes 2 to absorb any unavoidable discrepancy in the pitch P between the bolt holes 2, and the pitch P1 between the threaded holes 7 formed in the knuckle 6. But with this arrangement, it is impossible to fix the caliper stably enough. When braking torque acts on the caliper 1, the caliper 1 tends to turn in the direction M in Fig. 5 by angular moment by a distance permitted by the clearances t as shown by chain line in Fig.5, if the tightening force by the mounting bolts 3 are not enough. In the state shown by the chain line, the caliper mounting portion at the disk-leading side has moved toward the disk rotor 8, while the caliper mounting portion at the disk-trailing side has moved away from the disk rotor 8. Such dislocation of the caliper tends to deteriorate the braking performance, cause uneven wear of the pads 4, and increase the brake squeaks. An object of this invention is to prevent turning of the caliper due to the clearances between the mounting bolts and the bolt holes. According to this invention, there is provided a radial-mount type disk brake comprising a caliper, a disk rotor, a knuckle for supporting the caliper, the caliper being formed with bolt holes extending perpendicularly to the axis of a disk, and mounting bolts each inserted through the bolt holes and threaded into the knuckle to fix the caliper to the knuckle, characterized in that abutment surfaces of the caliper and the knuckle include at least one surface perpendicular to the axis of the disk. The abutment surfaces perpendicular to the disk axis are preferably arranged such that the surface of the caliper at its disk-leading side faces an end face of the disk rotor, and the surface of the caliper at its disk-trailing side faces away from the disk. Also it is preferable to provide two or more of such perpendicular surfaces parallel to each other. Such perpendicular surfaces may be formed on separate members (such as collars) mounted on the caliper. Since the abutment surfaces of the caliper and the knuckle have surfaces perpendicular to the disk axis, pivoting of the caliper by the angular moment M in Fig. 5 is prevented by the binding action of these surfaces. Although this effect will reveal to the maximum if two or more of such perpendicular surfaces are provided parallel to each other, one can expect this effect anyhow by providing one each such surface at the disk-leading and disk-trailing sides. But in the latter arrangement, the effect may lessen according to the positions of the surfaces. Therefore, in the latter arrangement, the surface positioning as shown in Fig. 1 is preferable. Other features and objects of the present invention will become apparent from the following description made with reference to the accompanying drawings, provided by way of example, in which: Fig. 1A is a plan view of a brake embodying the invention; Fig. 1B is a back view of the same; Fig. 1C is a partially cutaway side view of the same showing the caliper mounting portion at the disk-leading side; Fig. 1D is a partially cutaway side view of the same showing the caliper mounting portion at the disk-trailing side; Fig. 2A is a partially cutaway side view of the caliper mounting portion of another embodiment; Fig. 2B is a sectional view taken along line X-X of Fig. 2A; Fig. 3A is a partially cutaway side view of a further embodiment having three surfaces perpendicular to the disk axis; Fig. 3B is a sectional view taken along line Y-Y of Fig. 3B; Fig. 4A is a partially cutaway side view of a still further embodiment in which a collar is used to prevent turning; Fig. 4B is a perspective view of the collar received in the knuckle; Fig. 5 is a plan view of a conventional radial-mount type disk brake; Fig. 6 is a back view of the brake of Fig. 5; and Fig. 7 is a partially cutaway side view of the brake of Fig. 5 showing its caliper mounting portion. Fig. 1 shows a disk brake embodying this invention. In the figure, numeral 1 designates a caliper. Bolt holes 2 are formed in the caliper 1 at its disk-leading and disk-trailing sides so as to extend perpendicularly to the axis of the disk to receive mounting bolts 3. Pads 4 hang from pad pins 5. Threaded holes 7 are formed in a knuckle 6. Numeral 8 is a disk rotor. The pads 4 are biased by an unillustrated actuator mounted in the caliper 1. Clearances t (Figs. 1C, 1D) are provided between the bolt holes 2 and the mounting bolts 3 to absorb any variation in the pitch between the bolt holes 2. What has been described above is nothing different from the prior art. What distinguishes the illustrated disk brake over the prior art is the provision of surfaces 10 extending in a direction perpendicular to the axis of the disk so as to form steps or shoulders on the abutment surfaces between the caliper 1 and the knuckle 6 (see Figs. 1B-1D). In the embodiment of Fig. 1, one surface 10 is formed each at the disk-leading side and the disk-trailing side. The surface 10 at the disk-leading side is located farther from the disk rotor 8 than is the mounting bolt 3 as shown in Fig. 1C, while the surface 10 at the disk-trailing side is located between the disk rotor 8 and the mounting bolt 3 as shown in Fig. 1D. In other words the former surface faces toward the disk rotor 8 whereas the latter surface faces in the opposite direction to above. But both of the surfaces 10 at the disk-leading and disk-trailing sides may be provided farther from or nearer to the disk rotor 8 than are the bolts 3. Even in this arrangement, it is possible to suppress the caliper's pivoting motion compared with the conventional arrangement in which the clearance allows pivoting of the caliper. In Fig. 1, two flat surfaces 10 are provided at the disk-leading and disk-trailing sides, respectively, so as to be parallel to each other. But one of them may be omitted. But in order to more positively prevent the caliper's pivoting motion, two flat surfaces should be provided as shown in Fig. 1. As shown in Figs. 2 and 3, two or more parallel flat surfaces 10 may be formed to fit the caliper 1 and the knuckle 6 together in the radial direction of the disk. In this arrangement, the binding action of the surfaces 10 prevents the caliper 1 from pivoting due to braking torque, while the disk is rotating in either direction. In the embodiment of Fig. 4, a collar 11 is inserted in one or both of the bolt holes 2 at its exit and its lower portion is received in a recess 12 formed in the knuckle 6 to prevent the caliper 1 from pivoting. In this case, the collar or collars 11 have to be of such a size that a suitable clearance is created between the collar and the mounting bolt 3. If two such collars are used, the recesses 12 are preferably grooves extending parallel to the end face of the disk rotor 8 so that the bolts can be tightened even if the pitch between the recesses or the pitch between the collars should not coincide with each other (due to manufacturing error). This invention is applicable to any types of the disk brake in which the pads are biased by a hydraulic, electric or manual actuator. Also, this invention is applicable not only to the illustrated opposed-piston type but to the floating type. As described above, according to this invention, abutment surfaces of the caliper and the knuckle include a surface perpendicular to the disk axis to prevent pivoting of the caliper resulting from the clearances between the bolt holes and the mounting bolts. By preventing pivoting of the caliper, it is possible to maintain braking performance, and suppress uneven wear of pads and squeaks. Since the caliper can be prevented from pivoting without relying upon the mounting bolts, the bolt holes may have a greater diameter (and thus the clearances between the holes and the bolts may be greater) than before. This makes it possible to loosen the positional accuracy of bolt holes and threaded holes. Machining thus becomes easier.

Claims: A radial-mount type disk brake comprising a caliper (1), a disk rotor (8), a knuckle (6) for supporting said caliper (1), said caliper (1) being formed with bolt holes (2) extending perpendicularly to the axis of the disk rotor (8), and mounting bolts (3) each inserted through said bolt holes (2) and threaded into said knuckle (6) to fix said caliper (1) to said knuckle (6), characterized in that abutment surfaces (10) of said caliper (1) and said knuckle (6) include at least one surface perpendicular to the axis of the disk rotor (8). The disk brake claimed in claim 1 wherein the at least one abutment surface of said caliper (1) and said knuckle (6) include two surfaces (10) formed on said caliper (1) perpendicularly to the axis of the disk rotor (8) at its disk-leading and disk-trailing sides, one of the surfaces at the disk-leading side facing toward said disk rotor (8), and the other of the surfaces at the disk-trailing side facing away from said disk rotor (8). The disk brake of claim 1 wherein two or more said surfaces (10) perpendicularly to the disk axis rotor (8) are provided and are parallel to each other. The disk brake of claim 1 wherein a collar (11) is mounted at the exit of at least one of said bolt holes (2) of said caliper (1) for passing one of said mounting bolts (3) with a predetermined clearance such that said collar (11) protrudes from said caliper (1) into said knuckle (6), said at least one surface (10) perpendicular to the disk axis being formed by the outer peripheral surface of the protruding portion of said collar.

Inventors: MATSUZAKI YOSHIKI, MATSUZAKI, YOSHIKI, Matsuzaki, Yoshiki, c/o Itami Works
Applicants: SUMITOMO ELECTRIC INDUSTRIES, SUMITOMO ELECTRIC INDUSTRIES, LTD.
Application year: 1999
Main classification: F16D55
IPC codes: F16D65, F16D55