JPH0450458B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to improvements in disc brakes used for braking automobiles.

As shown in Fig. 1, a disc brake consists of a support 2 fixed to the vehicle body across the edge of a rotor 1 that rotates with the wheels, and a back metal and lining placed on both sides of the edge of the rotor 1. A pair of front and back pads 3 are supported so as to be slidable in a direction perpendicular to the plane of the paper, and a caliper 4 is attached to the support 2 so as to be slidable in a direction perpendicular to the plane of the paper. When performing braking, when the inner side (piston side) pad is pressed against the side surface of the rotor 1 by the piston installed in the caliper 4, the caliper 4 supported on the support 2 slides slightly as a reaction.
The outer pad is pressed against the other side of the rotor 1 via the caliper pawl 4a, and the edge of the rotor 1 is strongly clamped between the two pads from both sides to perform braking.

Incidentally, in a disc brake constructed and operated in this manner, a noise called squeal is often generated during braking. As a result of research on such noise, the inventors of the present invention have learned that most of the causes of noise are resonance of the pads caused by friction between the side surfaces of the rotor 1 and the pads.

In other words, when braking, the lining of the pads will touch the rotor 1.
When the pad 3 strongly rubs against the side of the
The parts on both sides of the part vibrate in a wave-like manner, producing noise. The frequency of this noise changes as the number and position of vibration nodes change due to the structure of the disc brake, the force with which the pads are pressed, etc. For example, if we take the case of a regular disc brake pad for a small passenger car, as shown by the broken line in Figure 3, the joint lines a and a, which connect the joints, are located about 1/3 from both sides of the pad. Yes, and if the outer part (hatched part) and inner part (white part) of both nodal lines vibrate in opposite phases, approximately
When a noise of 2500 Hz is generated and the vibration nodal lines a and a are located at a position that bisects the length direction and width direction of the pad 3, as shown in Fig. 4, approximately
Generates 4800Hz noise. If the vibration nodal line a is at the position shown in Figures 5 to 8, and the shaded area and the white area vibrate in opposite phases, the vibrations will be 8300 Hz and 8300 Hz, respectively.
Noises of around 9800Hz, 13800Hz, and 14300Hz are generated.

The disc brake of the present invention prevents the generation of noise caused by the vibration of the pads as described above.
It was noted that the part slightly away from the center point O (Figures 3 to 8) of the pad 3 in the lengthwise and axial directions of the pad does not become a node of vibration no matter what frequency the pad vibrates. It was done by That is, by suppressing the point X, which is the antinode of the vibration or a part close to it, which is slightly deviated diagonally to the side from the central point O mentioned above, the vibration of any frequency as shown in FIGS. 3 to 8 can be suppressed. This prevents noise generation, especially from the outer pad pressed by the caliper pawl 4a.

Hereinafter, the present invention will be explained in more detail with reference to drawings showing examples.

9-10 show a first embodiment of the invention. A bolt 6 is fixed at a point X slightly lower left from the center point O of the back metal of the outer pad 3, which is pressed by the caliper claws 4a, 4a.
Both ends of the plate spring 7, whose intermediate portion apart from the center portion is supported by the bolt 6, are connected to the caliper claws 4a,
It is brought into elastic contact with the outer surface of 4a. Therefore, a point X slightly away from the center point O of the pad 3 is elastically supported by the caliper pawls 4a, 4a via the bolt 6 and leaf spring 7, and even if the pad 3 tries to vibrate, , as shown in Figures 3 to 8, when the pad 3 vibrates at any frequency, the point Therefore, the noise accompanying the vibration of the pad can be prevented or reduced to the extent that it is practically inaudible.

Note that, as shown in FIG. 11, if the leaf spring 7 is made long and both ends of the leaf spring 7 protruding to the sides of the caliper claws 4a, 4a are fixed to the back metal 5, the point X can be suppressed. It can be made even stronger. Further, as shown in FIGS. 12 and 13, a pot-shaped hole 8 is formed in the leaf spring 7, and a mushroom-shaped projection 9 planted at the X point of the back metal 5 of the pad is locked in the hole 8. By doing so, the attachment of the leaf spring 7 can be performed even more easily. Furthermore, in the illustrated example, the X points for supporting the pad are both provided to the lower left of the center point O of the pad, but the X point is located in the longitudinal direction of the pad with respect to the center point O. As long as they are slightly shifted from each other in the width direction, it goes without saying that they may be placed at the upper left, upper right, or lower right, in addition to the illustrated example.

FIG. 14 is a diagram showing the results of a squeal generation test using the pad according to the present invention, and it can be seen that according to the present invention, there is almost no generation of loud squeals.

In Figure 14, the noise levels 1 to 5 indicate the following: 1: Very audible 2: Audible but not bothersome 3: Slightly bothersome 4: Noisy 5: Very noisy, and the occurrence rate (%) of the squeal is Squeal occurrence rate = number of occurrences of each squeal size/total number of braking times x 100. The test consisted of nine types of brake fluid pressure and nine types of pad temperature, and each combination was tested three times, for a total of 243 times. It can be seen that the noise prevention effect is extremely superior compared to conventional products and those with the spring located in the center of the pad.

Since the disc brake of the present invention is constructed as described above, by simply modifying the conventional disc brake, it is possible to effectively prevent noise caused by vibration of the pads, resulting in industrial effects. is large.

[Brief explanation of drawings]

Fig. 1 is a front view showing an example of a conventional disc brake, Fig. 2 is a plan view of the pad illustrating the vibration situation of the pad, and Figs. 3 to 8 show six examples of the vibration situation of the pad. 9 is a front view of the disc brake showing the first embodiment of the present invention, FIG. 10 is a sectional view taken along line A-A in FIG. 9, and FIG. 11 is similar to FIG. 10 showing the second embodiment. cross-sectional view, 1st
FIG. 2 is a partial front view of a disc brake showing a third embodiment, FIG. 13 is a sectional view taken along line BB in FIG. 12, and FIG. 14 is a line diagram showing test results for squeal prevention according to the present invention. 1... Rotor, 2... Support, 3... Pad, 4... Caliper, 4a... Caliper claw, 5...
... Back metal, 6... Bolt, 7... Leaf spring, 8...
Hole, 9...protrusion.

Claims (1)

[Claims] 1 A rotor 1 that rotates together with the wheels, and a rotor 1 that is disposed so as to be movable in the rotor axial direction across the rotor edge;
A pad pressing mechanism is built into the inner leg, and the outer leg is equipped with a caliper serving as a reaction part and a pair of pads facing each other with the rotor in between. In a disc brake that performs braking by pressing, the plane passing through the rotor axis and the center point of the pad is the first plane,
The second plane is a plane that is orthogonal to the first plane and the pad surface and passes through the center point of the pad. A point X on any one of the four faces of the pad divided by the second plane is connected to the middle part of a leaf spring 7 whose both ends are in elastic contact with the outer surface of the outer leg. A disc brake characterized by elastically suppressing the 3.