Compared to other braking components in the transmission (such as multi-disc clutches), the brake band offers unique advantages in structure and performance, making it particularly suitable for the complex operating conditions of automatic transmissions:
1.Simple structure, high reliability, and low maintenance costs·The brake band mainly consists of a "flexible brake band body" (usually wrapped with friction material), a "driving cylinder," and a "return spring." It has no complex multi-disc friction plates or sealing structures, resulting in fewer parts and concentrated, easy-to-inspect wear points. Even if wear occurs, only the brake band body or friction material typically needs to be replaced, without disassembling the core components of the entire transmission—leading to much lower maintenance costs than multi-disc clutches.
2.Stable braking force and strong impact resistance·The brake band achieves braking through "circular wrap-around clamping," which provides a larger contact area with the brake drum (compared to components with point contact or small-area surface contact). This allows it to evenly withstand high braking torques. Under conditions like sudden deceleration or load changes (e.g., sudden acceleration), it is less prone to "slippage" or "instantaneous overload damage," ensuring more stable braking force output and extending the transmission’s service life.
3.Suitable for high-torque scenarios and compact space requirements·The circular structure of the brake band can be arranged around the brake drum of the planetary gear set, without occupying additional radial space—making it ideal for the compact internal layout of automatic transmissions. Additionally, its friction materials (such as asbestos-based or semi-metallic materials) can withstand high temperatures and torques, so it is widely used in automatic transmissions of large-displacement vehicles or heavy-duty vehicles (e.g., SUVs, commercial vehicles) to meet high-load power transfer needs.
4.Direct shifting response and reduced power interruption
·The brake band is driven by a hydraulic cylinder. Hydraulic drive offers fast response speeds (compared to mechanical transmission), allowing it to complete the "contraction-braking" or "release-brake release" actions in milliseconds. This reduces the power interruption time during gear shifts and improves driving smoothness.