Analysis of the difference between RV reducer and harmonic reducer
Author: Ever Power Date: 2019-02-13 Source: Attention:
Analysis of the difference between RV reducer and harmonic reducer
As an important component of core components, precision reducers are an indispensable part of the precise operation of industrial robots.There are many types of reducers, namely, harmonic gear reducer, cycloid planetary reducer, RV reducer, precision planetary reducer and filter gear reducer.
As a precision reducer, the core component of industrial robots, compared with general-purpose reducers, the reducer for robots requires the characteristics of short transmission chain, small size, high power, light weight and easy control.The precision reducer makes the robot servo motor run at a suitable speed, and accurately reduces the speed to the speed required by each part of the industrial robot, which improves the rigidity of the mechanical body while outputting greater torque.
There are two main types of reducers widely used in articulated robots: RV reducers and harmonic reducers.Generally, the RV reducer is placed on the machine base, boom, shoulder and other heavy loads, that is, it is mainly used for robot joints over 20 kg; and the harmonic reducer is placed on the forearm, wrist or hand, that is, Robot joints under 20 kg.In addition, planetary reducers are generally used on Cartesian robots.
RV-E type reducer
So, what are the principles, advantages and disadvantages of the two types of reducers?
Chen Fei from EVER-POWER GROUP CO., LTD explained that the harmonic reducer is composed of four basic components: "flexible wheel, wave generator, rigid wheel, and bearing".The outer diameter of the flexible wheel is slightly smaller than the inner diameter of the rigid wheel. Generally, the flexible wheel has 2 teeth less than the rigid wheel.The elliptical shape of the wave generator determines that the tooth contact points of the flexible wheel and the rigid wheel are distributed on two opposite surfaces between the center of the ellipse.During the rotation of the wave generator, the contact parts of the flexible gear and the rigid gear start to mesh.Every time the wave generator rotates 180° clockwise, the flexspline is equivalent to a counterclockwise rotation of the rigid wheel by 1 tooth number difference.At two 180° symmetrical positions, more than 30% of all teeth are meshed simultaneously, which also results in high torque transmission.
Harmonic reducer
Chen Fei believes that compared to harmonic reducers, RV transmission is a new type of transmission. It is developed on the basis of traditional pin-vibration planetary transmission. It not only overcomes the shortcomings of general pin-vibration transmission, but also has small size. , Light weight, wide transmission ratio range, long life, stable accuracy, high efficiency, stable transmission and other advantages.
The key to the RV reducer is the processing technology and assembly technology. RV reducer has higher fatigue strength, rigidity and lifespan. Unlike the harmonic drive, as the use time increases, the movement accuracy will be significantly reduced. Its disadvantage is that it is heavy in weight and large in size.
It is reported that the RV reducer is composed of a cycloidal pin wheel and a planetary support. It is widely used in industrial robots and machine tools with many advantages such as small size, strong impact resistance, large torque, high positioning accuracy, low vibration, and large reduction ratio. , Medical testing equipment, satellite receiving systems, etc., are increasingly receiving extensive attention at home and abroad.
Dr. Chen Fei from EVER-POWER GROUP CO., LTD further analyzed the advantages and disadvantages of RV reducer and harmonic reducer.He believes that the harmonic reducer has a simple and compact structure and is suitable for miniaturized, low and medium load applications. RV has good rigidity, strong impact resistance, stable transmission, and high precision. It is suitable for medium and heavy load applications. However, RV reducers need to transmit large torques, withstand large overload impacts, and ensure expected working life. A relatively complex over-positioning structure is used on the above, and the manufacturing process and cost control are difficult.
In summary, the seemingly simple reducer is actually a challenge to my country's industrial infrastructure system.It is unexpected that it is difficult to produce a precision reducer that fully meets the requirements of robots without thoroughly understanding the relevant materials, heat treatment, and technology.
