The stepper motor is known for its precise positioning and high torque output at low speeds. Still, they require careful sizing to ensure that the motors match the load and application parameters, to minimize the possibility of out-of-step or motor stall. Gearbox Stepper Motorcan improve Motor performance by reducing the inertia ratio of load to Motor, increasing load torque, and reducing Motor oscillation.

Reduce the motor load inertia ratio

One reason for the lack of step distance in stepper motor applications is inertia. The ratio of load inertia to motor inertia determines how the motor can drive or control the load, especially in the acceleration and deceleration parts of the motion curve. If the load inertia is significantly higher than the motor inertia, the motor will have difficulty controlling the load and may overshoot (Overspeed steps out of range) or undershoot (underspeed steps). A high load-to-inertia ratio can also cause the motor to consume too much current and shut down.

One way to reduce the inertia ratio is to use motors with greater inertia. But that means higher costs, more weight, and drip effects on other parts of the system, such as couplings, cables, and drive components. Instead, adding a gearbox to the system reduces the square of the gear ratio by the inertia ratio of the load to the motor.

Increase load torque

Another reason for choosing Gearbox Stepper Motor is to increase the torque available to drive the load. When the load is driven by a motor-gearbox combination, the gearbox multiplies the torque of the motor by an amount proportional to the gear ratio and gearbox efficiency.

But while transmissions increase torque, they reduce speed. (this is why they are sometimes called“Gear reducers” or“Reducers.”) In other words, when the gearbox is connected to the motor, the motor must rotate faster-equal to the gear ratio to deliver the target speed to the load.

Also, due to braking torque and other losses, stepper motor torque usually decreases rapidly as speed increases. This inverse relationship between speed and torque means that it is only feasible to increase speed by a certain amount until the motor can not deliver the required torque, even by multiplying the gear ratio.

Note that the stepper motor's continuous torque (green) decreases rapidly with speed, unlike the servo motor's continuous torque (blue), which is relatively flat even at high motor speed.

Reduce resonance and vibration

But accelerating the motor does have its advantages. When the gearbox is installed, the additional speed required by the motor means that the motor operates outside its resonant frequency range, where vibration and vibration can cause the motor to stall or stall.

Gearbox Stepper Motor (top) shows significantly less vibration than gearless Stepper Motor (bottom), especially at low speeds in the resonant frequency range.

In addition to ensuring that the gearbox has the proper torque, speed, and inertia values, it is also important to select high-precision, low-recoil gearboxes-especially when connecting the gearbox to a stepper motor.

Recall that stepping motors operate in an open-loop system, and the clearance in the gearbox reduces the system's positioning accuracy without feedback to monitor or correct positioning errors. This is why stepping applications often use high-precision planetary gearboxes with clearances as low as 2 to 3 arc minutes. Some manufacturers offer stepper motors with harmonic gears that achieve zero back clearance for most applications.

Baolong MOTOR was founded in 2004 and has a profound technical background and rich experience in the MOTOR industry, we have developed stepping servo motor, stepping linear motor, motor driver, DC brushless motor, AC servo motor, Gear Box, and other products, for more information onGearbox Stepper Motor, contact us at sales01@baolongmotor.com.