Quick completion guide for manipulator (4): reducer of key components of manipulator

Directory ：

Quick completion guide of mechanical arm （ zero ）： Main contents and analysis methods of the guide

Quick completion guide of mechanical arm （ One ）： The development of manipulator

Quick completion guide of mechanical arm （ Two ）： Application of mechanical arm

Quick completion guide of mechanical arm （ 3、 ... and ）： Mechanical structure of mechanical arm

Quick completion guide of mechanical arm （ Four ）： Reducer of key components of mechanical arm

Quick completion guide of mechanical arm （ 5、 ... and ）： End actuators

Quick completion guide of mechanical arm （ 6、 ... and ）： Stepper motor driver  

         After more than 30 years of development , The rapid development of domestic manipulator , But compared with foreign manipulator products , Experience in application 、 There are still some gaps in the functional system and accuracy . After reading the Internet and various references 、 After the introduction of the textbook , In my submission , Some things can not catch up with the international leading level just by virtue of their late development advantages , For example, the control software of the manipulator and its installation Key components , The lack of in-depth research on these two aspects has greatly restricted the development of manipulator in China .

One 、 The introduction

        Take my graduation project as an example , The hardware mainly includes the following contents ：

        below , I will focus on the introduction and analysis of the reducer .

Two 、 Reducer

        Reducer is an important component to improve the operating accuracy and torque of manipulator joints , Common reducers are planetary reducers 、 Cycloidal pin wheel reducer 、 Harmonic reducer and RV Reducer .

1. Planetary reducer

Schematic diagram	3D Simulation diagram	A physical picture （ Bevel teeth ）

        The reducer I use is the planetary reducer , It has a small size 、 Light weight , High bearing capacity , Long service life 、 Smooth operation , Low noise . With power shunt 、 The unique characteristics of multi tooth meshing .

        The calculation method of reduction ratio is ： Let the number of stellar teeth be n_1, The number of planetary teeth is n_2, Then the deceleration ratio can be obtained as

 2. Cycloidal pin wheel reducer

         Cycloid pin gear reducer adopts cycloid pin gear meshing 、 Principle of planetary transmission , So it is usually called planetary cycloid reducer . The tooth profile of the external gear is Distorted cycloid （ Cycloid refers to a circle rolling on a fixed line , Track of a fixed point on the circumference , Also known as round rolling line 、 Roller line , As shown in the square diagram below ）, The internal gear teeth are Round pin , both of them Internal engagement . Cycloid pin gear reducer is widely used in petroleum industry 、 Environmental protection 、 chemical 、 cement 、 Transportation 、 Spin 、 Pharmacy 、 food 、 printing 、 Lifting 、 mine 、 metallurgy 、 Architecture 、 Power generation and other industries , As a driving or decelerating device .

        Its advantage is small size 、 Light weight , Wide range of transmission ratios , High transmission efficiency and smooth operation , The disadvantage is cycloid gear 、 Needle tooth pin 、 Needle tooth sleeve 、 The main parts such as pin and pin sleeve are made of good materials GCrl5 Bearing steel manufacturing , And some parts require high manufacturing accuracy , The manufacturing process is complicated ; At the same time, the bearing force of the rotating arm shaft is large , As a result, the speed of the high-speed shaft and the transmitted power are limited .

3. Harmonic Drive

A physical picture	Schematic diagram	Exploded view

         The harmonic reducer consists of a wave generator 、 Flexible gear 、 The rigid gear consists of three basic components , The utility model relates to a wave generator which is equipped with a flexible bearing to make the flexible gear produce controllable elastic deformation , A gear transmission that meshes with a rigid gear to transmit motion and power . It is in aviation 、 space flight 、 energy 、 Sailing 、 shipbuilding 、 Bionic machinery 、 Common ordnance 、 Machine tool 、 Meter 、 Electronic equipment 、 Mining metallurgy 、 The transportation 、 Hoisting machinery 、 Petrochemical machinery 、 Textile machinery 、 Agricultural machinery and medical devices have been widely used , Especially in the servo system with high dynamic performance , Using harmonic gear transmission shows its superiority .

        The main advantages of harmonic reducer are large transmission speed ratio 、 High bearing capacity 、 High transmission accuracy 、 High transmission efficiency 、 Simple structure 、 Small volume 、 Light weight and can transfer movement to the confined space ; The disadvantage is that the flexible wheel is prone to fatigue damage 、 Large moment of inertia and starting torque, and difficult to manufacture , The process is complex .

        Hammernaco is a leading company in this field .

4.RV Reducer

The first 1 Level deceleration	Crank shaft part	The first 2 Level deceleration
① The rotation of the servo motor is driven from the input gear to the spur gear , The tooth ratio of input gear and spur gear is the reduction ratio . ② The crankshaft is directly connected to the spur gear , It is the same as the rotation number of spur gear .	③ In the eccentric part of the crankshaft , Installed by needle roller bearing 2 individual RV gear .（2 individual RV A gear can achieve a balance of forces ） ④ As the crankshaft rotates , Installed in the eccentric part 2 individual RV The gear also moves eccentrically （ Crank movement ）.	⑤ One side , In the needle tooth groove measured in the shell , Than RV The number of teeth of the gear is more than one, and the needle tooth slots are arranged equidistant . ⑥ Crank shaft rotates once ,RV When the gear is in contact with the needle tooth groove, it makes an eccentric motion （ Crank shaft movement ）. On this result ,RV The gear rotates a gear distance in the direction opposite to the direction of rotation of the crankshaft . ⑦ The rotation on the output shaft is obtained by means of the crank shaft , The rotation speed of the crank shaft is distinguished according to the number of needle slots . ⑧ The total reduction ratio is 1 The reduction ratio of the first stage reduction and the 2 The product of the reduction ratio of the stage reduction .

        RV The reducer is composed of a front stage of a planetary gear reducer and a rear stage of a cycloidal pin gear reducer ,RV The reducer has a compact structure , High transmission ratio , And transmission machinery with self-locking function under certain conditions , It is one of the most commonly used reducers with small vibration , Low noise , Low energy consumption .

         Usually ,RV Reducer is used for joints with large torque , Such as joints 1、2、3. stay RV The big player in the field of reducer is nabotesk transmission equipment company in Japan , In the international monopoly .