| 摘要 |
PURPOSE: A drum brake for a motor vehicle is provided to reduce the possibility of the generation of a squeal by differentiating each natural frequency of a right and a left brake shoes for a coupled vibration to be difficult to occur. CONSTITUTION: A drum brake for vehicles which applies a brake by pressing a pair of brake shoes having the same size on the inner surface of a brake drum, wherein the pair of brake shoes are made of materials having mutually different natural frequencies. Alternatively, the natural frequency of a trailing shoe may be greater than the natural frequency of a leading shoe. Furthermore, the main body of the leading shoe of the pair of shoes may be made of a steel sheet whereas the main body of the trailing shoe may be made of a cast iron. In the first and second inventions described above, coupled vibration is difficult to occur at the time of braking and the chance of the occurrence of "screeching" becomes extremely small. In the third invention described above, the coupled vibration is difficult to occur in the same way as in the second invention, and not only the chance of the occurrence of "screeching" becomes small but the vibration of the steel sheet shoe can be effectively suppressed by the drum itself and through the drum when the resonance with the brake drum occurs on the side of the steel sheet shoe of the leading shoe because the cast iron shoe of the trailing shoe has large damping force, a large specific gravity and a large weight due to its characteristics. Further, this drum brake can be produced in the same way as ordinary brake shoes by merely changing the shoe material.
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