Home page

Automatic brake gap adjusting arm structure come to understand it

Release time:

2023-07-21 08:30

Source:

automatic adjusting arm is generally composed of housing (shell, bushing), transmission part (worm, worm wheel), one-way clutch (gear, clutch spring, clutch ring), control device (control wheel, control arm, cover plate, rack, Return spring) and worm compression part (worm spiral spring, thrust washer, screw cover, needle bearing, worm bearing, etc.).
The control arm is one of the key components that distinguish the automatic adjusting arm from the manual adjusting arm. It is fixed on the chassis, so that the brake gap is automatically adjusted as a reference point when the gap of the arm is adjusted, and the manual adjustment arm does not have this part. The notch in the control arm assembly corresponds to the clearance angle, I .e. the normal clearance between the friction lining and the brake drum.
One-way clutch is composed of gear, clutch spring and clutch ring. During the braking process, the rack drives the gear to rotate clockwise. Since the gear moves in the same direction as the clutch spring, the clutch spring has a tendency to contract radially, which reduces the friction between the clutch ring, the inner surface of the gear and the rectangular surface of the spring. Therefore, the gear can rotate relative to the clutch ring to record the wear caused by the brake. This working state of the one-way clutch is called the separation and slip state. When the brake is returned, the gear rotates counterclockwise under the drive of the rack. Because the steering is opposite to the clutch spring, the clutch spring tends to become larger in the radial direction, which increases the friction between the clutch, the inner surface of the gear and the rectangular surface of the spring, so the gear cannot move relative to the clutch ring, causing the rack to rotate the entire one-way clutch assembly. It is said that the one-way clutch is in a combined state at this time.
The function of the one-way clutch is: ①When braking, the one-way clutch converts the linear movement of the rack into axial rotation. Record the excess clearance due to wear of the friction lining. ②When braking, the one-way clutch is disengaged and slipping; when the brake is returned, the one-way clutch is engaged to ensure that the adjusting arm is adjusted when the brake is about to end.
The cone clutch is composed of the end of the worm and the clutch ring. Both the cone part of the worm and the inner side of the clutch ring have teeth. When the two mesh, it is called the cone clutch combination. When the worm axial movement, worm conical parts and clutch ring disengagement, said cone clutch separation. When the friction lining presses the brake drum and the S camshaft angular stroke enters the elastic zone, the braking torque rises rapidly, causing the worm to move axially, overcoming the pressure of the coil spring, and causing the cone clutch to disengage. At this time, the one-way clutch does not record the spring angle (E) in the angular stroke. When the brake is returned, the braking torque drops, and the coil spring returns to its original state, pushing the worm back to the original place to combine the cone clutch. At this time, the angular stroke of the S camshaft returns to the gap area. The rack drives the worm according to the excess clearance recorded by the one-way clutch, rotates the worm wheel, and completes one adjustment. Therefore, the function of the coil spring and the cone clutch is to ensure that the adjustment arm does not produce errors caused by elasticity when recording and adjusting the excess gap.

automatic adjusting arm

How does the automatic brake gap adjusting arm work?