| 초록 |
The brake system is one of the key components of a vehicle, significantly impacting the driver's safety and driving convenience. Squeal noise during braking is generated when friction-induced vibration (friction aspect) occurs between the pad and disc during braking torque generation and transmission. This noise is caused by unstable contact between components (behavior aspect), which is combined with the inherent vibration characteristics of the vehicle's chassis system (resonance aspect). In particular, low-frequency squeal noise in the 1-3kHz range tends to occur at high sound pressure levels, making it easily noticeable to customers. It often arises under low-speed and low-pressure conditions, especially in premium and mid-to-large-sized vehicles equipped with discs larger than 17 inches. When categorizing improvement specifications for squeal noise issues from past vehicle models based on noise factors, many issues were related to caliper behavior (pad behavior and contact pressure). Specifically, the low-frequency squeal noise in the 1-3kHz range, which occurs under low-speed and low-pressure braking conditions, is mainly caused by caliper behavior and the contact pressure characteristics of the torque transfer surface. There are limitations to improving this type of squeal noise by analyzing it from a resonance perspective through methods such as modal analysis, FIM (Friction Induced Modal) analysis, and squeal noise analysis (Complex Eigenvalue Analysis). This study focuses on improving low-frequency squeal noise in the 1-3kHz range, which is presumed to be caused by factors related to caliper behavior under low-speed and low-pressure conditions. To analyze the cause of the noise, caliper behavior and contact pressure at the torque transfer surface were measured during actual squeal noise occurrence on a noise dynamometer. Based on this analysis, improvement specifications were selected, and verification evaluations were conducted, which are summarized in this paper |
