What Are Speed Reducers? How Do They Work?

Thursday - 20/01/2022 11:38

What Are Speed Reducers? How Do They Work?

Speed reducers (or gearboxes) are gearing assembly generally used in automation control systems to reduce the input power speed, usually from motors, to achieve desired output speed and torque.
Similar quality and complexity gearing processing works did not appear until the 13th to 14th centuries. Even if its function is a mechanical astronomical clocks instead of a speed reducer, such precise metal gearing skills and the use of different gear combinations to obtain the required output speed may have appeared thousands of years ago.  

What is the principle of speed reducers?

There are many ways to reduce motor speed in industrial applications, the most commonly used method is gear assembly (gearbox). Speed reducers or gearboxes reduce motor rotational speed while increasing motor output torque, which means increasing the amount of usable work. The motor power is transmitted through motor shaft to a gear train (assembled by small gears, large gears and a housing) in a speed reducer, and delivered by speed reducer output shaft.
Why use speed reducers?

Speed reducers or gearboxes are used to reduce motor rotation speed and increase output torque, which is equivalent to improve the working capacity of the motor. In addition, the output direction change is available through a speed reducer. The motor output shaft clockwise rotation can be changed to counterclockwise through a speed reducer, or the output direction is turned 90 degrees by a right angle gearbox to save the installation space.
What are the benefits of using speed reducers?

Reduce costs

Generally the purchase cost of the motor is relatively much higher than that of the speed reducer. The motor torque is increased by the speed reducer, which means the output capacity of the motor is increased, too. The required output power is achieved by a smaller motor equipped with a speed reducer instead of purchasing a high power motor. The cost of the overall configuration can also be reduced greatly.

Protect the motor

The speed reducer is installed between the motor and the machinery, and will bear a large torque loading from the machinery during operation. The speed reducer will be damaged first when overload, to prevent the motor from high loading and damage directly. At the same time, the cost of repairing or replacing the speed reducer is relatively low, which can also reduce maintenance costs.

Save energy

The motor may run at a lower speed in order to meet the required torque when the motor is directly connected to the machinery or equipment. Lower rotation speed will result in current rise significantly and consume more energy. The motor will also generate heat at the same time. High temperature may affect the performance and service life of the motor, and is likely to cause the motor to burn out in case of poor ventilation. Therefore, the use of a speed reducer can help to reduce energy consumption and to avoid damage to the motor.
What are the types of speed reducers?

There are a very diverse range of speed reducers and gearboxes. Here are few of common ones such as cylindrical gear reducers, worm gear reducers, planetary gearheads, cycloidal gearheads and harmonic gearheads according to structures and transmission methods. Gears provide a high output torque, high efficiency, wide range of ratios, and are available in multiple gearing assembly configuration.

Worm Gear Reducers

A worm gear reducer is one type of speed reducer consists of a worm pinion input, an output worm wheel, and are set at a right angle output orientation. Worm gear reducers are a popular type of speed reducer because they offer low initial and maintenance cost, high ratios and high output torque in a compact design package. The worm cannot be driven backwards due to high friction between the worm pinion and the worm wheel. They are easily to be mounted or coupled to an electric motor, but the efficiency decreases as the ratio increases.  
Planetary Gearheads (Planetary Gearboxes)

Planetary gearboxes have properties of high precision, high output torque, high efficiency , low backlash and low noise. High transmission ratios can be easily achieved by planetary gearboxes. Besides, quality planetary gearboxes are maintenance-free for service life, and have no need to change lubricant. Because of the features and compact design, the gear manufacturing processes are more complicated, and the precision machining are required. Planetary gearheads are commonly installed with servo motors or stepping motors to increase output torque and to meet the needs of dynamic control and precise positioning.

Cycloidal Speed Reducers

A cycloidal speed reducer uses the principles of cycloidal gears to provide high gear ratios with excellent backlash, high torsional stiffness, good shock load capacity, stable operation and less wear over the gearbox life.
Harmonic Reducers

Harmonic reducers are gearboxes based on the strain-wave principle in which a flexible ring with external tooth driven by an oval wave generator and rotates in a rigid ring gear. They provide extreme high transmission accuracy, high ratios, low inertia and compact installation. The features make harmonic reducers a great solution for robotic and accurate positioning applications.
Where are speed reducers used?

As mechanically power transmission industrial devices, speed reducers seems to be far away from general public, and even many people have heard the term for the first time. In fact, they are closer to our lives than we thought. Speed reducers initially did only appear in machinery, but now they are found in not only industrial products but also civilian applications such as electric motorbikes and e-bikes with the continuous improvement of economic development and metal processing technology over the years.

    Machine Tools

    Metal cutting machines, machining centers, CNC drilling machines, lathes and turning machines, milling and boring machines, grinding machines, metal forming machine tools, presses, tube and wire processing machines, water jet.

    Industrial Machinery

    Packaging machinery, food and beverage machinery, bakery equipment, agricultural machinery, textile machinery, shoemaking machinery, wood working machinery, printing machinery, plastic processing machinery, PET blowing molding machines, laser cutting and welding machines.


    Conveyors, automated storage, industrial robotics, automated guided vehicles, automatic labeling machines, automatic filling systems, packing palletizers, capping machines.

    Aerospace & Energy Sectors

    Radio telescope actuator, solar panel tracking.

    Medical & Testing Sectors

    Electric wheel chairs, moving assist robots, face mask machines, MRI bed, physiotherapy products, auto sampling system

    Electric Vehicles & Transportation

    Scooters, electric motorbikes, e-bikes, electric mobility, speed gates, access control gates

Why Dolin Motor?

Dolin has more than many years of motors, gear motors speed reducers manufacturing and sales experience. Dolin is mainly engaged in the research and development, production, manufacturing and marketing of induction motors, gear motors, speed reducers and high-precision planetary gearboxes. Our advantages come from:

    Years of experience in engineering and manufacture of quality induction motors, gear motors and gearboxes, which can assist in selecting the best part for your need and customization to your exact specifications from basic power transmission to high dynamic motion and precise positioning control.

    Continue expansion of plant, facilities, machining lines and quality control equipments to increase key-parts self-manufacturing ability and shorten lead time.

    R&D teams and project development capabilities provide customized services and feasible suggestions based on customer requirements.

    Dolin products are 100% made from the source of raw materials, research and development, design, machining and manufacturing with features of excellent quality, high precision, high efficiency and low noise.

    90% of the key components are self-made to ensure product quality and reliability for customers.

    Dolin is an ISO 9001 and ISO14001 certified company offering CE, CCC, UL certified products. We deliver products that consistently meet customer requirements, satisfaction and offer a service that can be relied on.

    Dolin is not only a brand with a high domestic market share, but also marketed in more than 50 countries around the world. There are more than 30 agents and distributors providing global customers with pre-sales consultation and after-sales service.


Gearboxes are available by precise gear parameter calculations, hobbing, surface treatment, grinding and other techniques, as well as matching of different size gears, to achieve the requirement of reducing motor speed and increase output torque. According to IEA (International Energy Agency), the electric motors and systems they drive are the largest single-energy end use and account for 46% of global electricity consumption.

From the perspective of energy saving and carbon reduction, the use of speed reducers is also an effective way in addition to improving the energy efficiency of electric motors. Beside industrial usage, demand from robotics, automation and electric vehicles for speed reducers or gearboxes is increasing due to popularization and affordability of such precise and unique applications.

Dolin has been deeply involved in the motors and speed reducers manufacturing for more than many years, and is regarded as one of more than one hundred companies related to the robotic industry supply chain since the gearbox is one of the key components in the robotic drive module. Dolin keeps focusing on the engineering and innovations of motors and gear drives, and providing stable and reliable power transmission components to precise automation applications in the era of Industry 4.0 and smart manufacturing.

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