Industrial robots are characterized by their high speed, accuracy, compact body structure, multiple degrees of freedom, and increased rigidity. Key areas also require heavy loads or fast response times. For example, most of the electric welding robots produced in automobile vehicles are between 150-300Kg, while the assembly robots in the electronic field need fast response to the accessories on the assembly line.
Industrial robots generally refer to humanoid arms, hand joints consisting of motors, speed reducers and robot bodies, and robot control systems. They are equipped with memory devices and end-effector devices and can complete various movements or processes to replace humans. General machine for labor. Used for industrial production robots. Usually in production, it can replace workers for certain monotonous, frequent and repeated long-term operations, or work in dangerous and harsh environments. It can improve the efficiency of production and the quality of products. It is an effective solution for companies to supplement and replace labor.
The reducer is an intermediate device connecting the power source and the actuator in the field of mechanical transmission. Usually, it reduces the power of high-speed operation such as the motor and the internal combustion engine through the pinion on the input shaft to engage the large gear on the output shaft to achieve the purpose of deceleration. And deliver more torque. The current mature and standardized reducer are: cylindrical gear reducer, turbo reducer, planetary reducer, planetary gear reducer, RV reducer, cycloid reducer and harmonic reducer. With the development of emerging industries such as aerospace, robotics and medical devices, high-performance precision speed reducers with simple, compact structure, high transmission power, low noise, and smooth transmission are required. Among them, RV speed reducers and harmonic wave reducers are precision speed reducers. The two important reducers in the device.
The RV reducer is developed on the basis of a cycloidal pin wheel drive and has a secondary deceleration and center disc support structure. Since it was put into the market in 1986, it has become a “royal” reducer for robots due to its advantages such as large transmission ratio, high transmission efficiency, high movement accuracy, small backlash, low vibration, rigidity, and high reliability.
Harmonic reducer consists of three parts: harmonic generator, flexible theory and rigid wheel. Its working principle is that the harmonic generator makes the flexible wheel controllably elastically deformed, and the flexible wheel meshes with the rigid wheel to transmit power. And to achieve the purpose of deceleration; according to the wave generator different cam type, roller type and eccentric disc type. The harmonic reducer has a large transmission ratio, a small profile, a small number of parts, and a high transmission efficiency. The single transmission ratio can reach 50-4000, and the transmission efficiency is as high as 92%-96%.
Planets, as their name suggests, are planetary speed reducers that are equipped with three planetary wheels that rotate around a sun gear. The planetary reducer is small in size, light in weight, high in load capacity, long in service life, stable in operation, and low in noise. With the characteristics of power split and multi-mesh engagement, it is a widely used industrial product. Its performance can be compared with other military grade planetary reducer products, but it has the price of industrial grade products and is applied to a wide range of industrial applications. .
The role of precision reducer
The power source of an industrial robot is generally an AC servo motor. Because the pulse signal is used to drive, the servo motor itself can realize speed regulation. Why does the industrial robot also need a reducer? 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 repeatability of industrial robots are highly demanding. Therefore, improving and ensuring the accuracy of industrial robots requires the use of RV reducers or harmonic reducers.
Another role of precision reducers in industrial robots is to transmit more torque. When the load is large, it is uneconomical to increase the power of the servo motor blindly, and it is possible to increase the output torque through a speed reducer within a suitable speed range. In addition, servo motors are prone to heat generation and low-frequency vibration at low-frequency operation, which is not conducive to ensuring accurate and reliable operation of industrial robots that work for a long time and periodically. There are two main types of reducers that are used in joint-type robots: RV reducers and harmonic reducers.
Compared to harmonic reducers, RV reducers have higher stiffness and revolution accuracy. Therefore, in the articulated robot, the RV reducer is generally placed at a heavy load position such as a seat, a boom, and a shoulder, and the harmonic reducer is placed on the arm, wrist, or hand; the planetary reducer is generally used On Cartesian robots.