常闭带式制动器和离合器是多功能履带式起重机的重要部件,国家标准规定, 起重机的卷筒制动器必须是常闭的结构, 主要是出于安全考虑,常开制动器受液压系统稳定性等因素限制,安全性不好。常闭带式制动器不同于常用的湿式片式制动 Normally closed brakes and clutches are important components of multi-purpose crawler cranes. The national standard stipulates that the drum brake of the crane must be normally closed structure, mainly for safety reasons. The normally open brake is affected by the stability of the hydraulic system and other factors Limitation, security is not good. Normally closed brake is different from the commonly used wet disc brake