Industrial robots can replace workers in production to do some monotonous, frequent and repetitive long-term operations, or operations in dangerous and harsh environments. It can improve production efficiency and product quality, and is an effective solution for enterprises to supplement and replace labor. 

At present, the development of industrial robots are high speed, precision, compact body structure,  freedom and improved rigidity. Key areas also require heavy loads or fast response speeds. For example, the load of welding robots in automobile production is mostly between 150-300Kg, while assembly robots in the electronics field need to respond quickly to accessories on the assembly line.

Why do industrial robots need reducers:

Bearing gravity torque: The joints of industrial robots need to bear the torque generated by gravity of the rear-end mechanism, which puts high demands on the reducer.

Stable speed: The speed of these joints is usually not high. The operation of the servo motor at an extremely low speed will cause unstable control, so a reducer is needed to keep the motor running smoothly at a reasonable speed.

High-precision requirements: High-precision positioning and repeated positioning are necessary conditions for industrial robots to complete tasks, and reducers play an important role in this process.

Reducer can solve the above problems, effective solutions need to be found in terms of torque, motor speed and precision.

In the field of mechanical transmission, reducers are intermediate devices connecting the power source and the actuator. Usually, they use the small gear on the input shaft to mesh the large gear on the output shaft of the high-speed power of electric motors and internal combustion engines to achieve the purpose of deceleration and transmit greater torque. At present, mature and standardized reducers include: cylindrical gear reducers, turbine reducers, planetary reducers, planetary gear reducers, RV reducers, cycloid pinwheel reducers and harmonic reducers. Since the 1980s and 1990s, under the development needs of emerging industries such as aerospace, robots and medical equipment, high-performance precision reducers with simple and compact structure, high power transmission, low noise and smooth transmission are needed. Among them, RV reducers and harmonic reducers are two important reducers in precision reducers.

Planetary reducers are an important part of industrial robots. The backlash of planetary reducers is very important and directly affects the accuracy of robots. Only when it is lower than 3 arcmin, it is considered high precision. This indicator should be paid attention to when selecting. Its performance directly affects the accuracy, stability and service life of the robot. Choosing a suitable planetary reducer can not only improve the overall performance of the robot, but also reduce maintenance costs and extend the service life of the equipment. Planetary reducers are used in precision assembly, testing and other links in the manufacturing of electronic products. The high precision and low backlash of planetary reducers can ensure that the robot can achieve micron-level positioning accuracy during the precision assembly process and improve the qualified rate of products.

In medical equipment, industrial robots are used for surgical assistance, drug distribution, etc. The high precision and low noise of planetary reducers can improve the reliability and safety of equipment and ensure the accuracy and stability of medical operations.

RV (Rot-Vector) reducer

RV reducer is developed on the basis of cycloid pinwheel transmission, with two-stage reduction and center disc support structure. Since it was put on the market in 1986, it has been the "royal" reducer for robots due to its advantages such as large transmission ratio, high transmission efficiency, high motion accuracy, small backlash, low vibration, high rigidity and high reliability.

Harmonic reducer

The harmonic reducer consists of three parts: harmonic generator, flexure wheel and rigid wheel. Its working principle is that the harmonic generator makes the flexure wheel produce controllable elastic deformation, and the flexure wheel and rigid wheel mesh to transmit power and achieve the purpose of deceleration; according to the different wave generators, there are cam type, roller type and eccentric disc type. Harmonic reducer has large transmission ratio, small outline, few parts and high transmission efficiency. The transmission ratio of a single machine can reach 50-4000, and the transmission efficiency is as high as 92%-96%.

The role of precision reducers in industrial robots

The power source of industrial robots is generally AC servo motors. Because they are driven by pulse signals, the servo motors themselves can achieve speed regulation. Why do industrial robots still need reducers? Industrial robots usually perform repetitive actions to complete the same process; in order to ensure that industrial robots can reliably complete process tasks in production and ensure process quality, the positioning accuracy and repeated positioning accuracy of industrial robots are very high. Therefore, to improve and ensure the accuracy of industrial robots, RV reducers or harmonic reducers are required. Another role of precision reducers in industrial robots is to transmit greater torque. When the load is large, it is not cost-effective to blindly increase the power of the servo motor. The output torque can be increased by a reducer within a suitable speed range. In addition, servo motors are prone to heat and low-frequency vibration under low-frequency operation, which is not conducive to ensuring the precise and reliable operation of industrial robots that operate for a long time and periodically.

The existence of precision reducers enables the servo motor to operate at a suitable speed and accurately reduce the speed to the speed required by various parts of the industrial robot, thereby increasing the rigidity of the mechanical body and outputting greater torque. Compared with general reducers, robot joint reducers are required to have the characteristics of short transmission chain, small size, high power, light weight and easy control. The reducers widely used in articulated robots are mainly RV reducers and harmonic reducers.

Compared with harmonic reducers, RV reducers have higher rigidity and rotation accuracy. Therefore, in articulated robots, RV reducers are generally placed in heavy load positions such as the base, upper arm, and shoulder; while harmonic reducers are placed in the forearm, wrist or hand; planetary reducers are generally used in rectangular coordinate robots.

RicoCNC can supply a series of reducer, especially Nidec Able planet reducer, such as VRSF-10C-750-LN, VRSF-10C-750-LM, VRSF-8B-LNS, VRSFS-40C-750-SD-T1, etc. if you are looking for them, welcome your inquiry.

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