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㈠. Mechanics

1. Gear transmission:

1) Classification: plane gear transmission, space gear transmission.

2) Features:

advantage

Applicable to a wide range of circumferential speed and power; Accurate, stable and efficient transmission ratio; High working reliability and long service life; It can realize the transmission between parallel shafts, intersecting shafts at any angle and intersecting shafts at any angle

shortcoming

It requires high manufacturing and installation accuracy and high cost; It is not suitable for long-distance transmission between two shafts.

3) Involute standard gear

The name of the basic dimension is addendum circle; Root circle; Graduation circle; Touch number; Angular pressure, etc.

2. Turbine scroll drive:

It is applicable to the motion and power between two axes that are vertical and do not intersect in space.

1) Features:

Advantages: large transmission ratio; Compact structure and size.

Disadvantages: large axial force, easy heating and low efficiency; Only one-way drive.

The main parameters of turbine scroll drive are: modulus; Pressure angle; Worm gear indexing circle; Worm indexing circle; Lead; Number of worm gear teeth; Number of worm heads; Transmission ratio, etc.

3. Belt drive:

Including driving wheel and driven wheel; Annular belt

1) It is used when two axes are parallel and the rotation direction is the same. It is called the concept of opening motion, center distance and wrap angle.

2) According to the cross-sectional shape, the type of belt can be divided into flat belt, V belt and special belt.

3) The key points in application are: Calculation of transmission ratio; Stress analysis and calculation of belt; Allowable power of single V-belt.

4) Features of belt drive:

advantage:

Suitable for transmission with large center distance between two axles; The belt has good flexibility, which can mitigate impact and absorb vibration; Slip during overload to prevent damage to other parts; The utility model has the advantages of simple structure and low cost.

Disadvantages:

The overall dimension of the transmission is large; Tensioning device required; Due to slipping, the fixed transmission ratio cannot be guaranteed; The service life of the belt is short; Low transmission efficiency.

4. Chain drive

Including driving chain and driven chain; Ring chain.

Compared with gear transmission, chain transmission has the following main characteristics: low requirements for manufacturing and installation accuracy; When the center distance is large, the transmission structure is simple; The instantaneous chain speed and instantaneous transmission ratio are not constant, and the transmission stability is poor.

5. Gear train

1) The gear train is divided into fixed axle gear train and epicyclic gear train.

2) The ratio of the angular speed (or rotational speed) of the input shaft to the output shaft in the gear train is called the transmission ratio of the gear train. Equal to the ratio of the product of the number of teeth of all driven gears in each pair of meshing gears to the product of the number of teeth of all driving gears.

3) In the epicyclic gear train, the gear whose axis position changes, that is, the gear that rotates and revolves, is called planetary gear, and the gear whose axis position is fixed is called central gear or sun gear.

4) The transmission ratio of epicyclic gear train cannot be calculated directly by solving the transmission ratio of fixed shaft gear train. It must be calculated by using the principle of relative motion and using the relative speed method (or reverse method) to convert epicyclic gear train into hypothetical fixed shaft gear train.

5) Main features of gear train:

It is applicable to the transmission between two shafts far apart; It can be used as a transmission to realize variable speed transmission; Larger transmission ratio can be obtained; Realize the synthesis and decomposition of motion.

㈡. electrical

1. High accuracy: as the power source, the servo motor is composed of ball screw and synchronous belt, which is a transmission mechanism with simple structure and high efficiency. Its repetition accuracy error is 0.01%.

2. Energy saving: the energy released in the deceleration stage of the working cycle can be converted into electric energy for reuse, so as to reduce the operation cost. The connected electric equipment is only 25% of the electric equipment required for hydraulic drive.

3. Precision control: realize precise control according to the set parameters. With the support of high-precision sensors, metering devices and computer technology, it can greatly exceed the control accuracy that can be achieved by other control methods.

4. Improve the level of environmental protection: due to the reduction of energy varieties and their optimized performance, the pollution sources and noise are reduced, which provides a better guarantee for the environmental protection work of the factory.

5. Reduce noise: its operating noise value is less than 70 dB, which is about 2 / 3 of the noise value of hydraulic driven injection molding machine.

6. Cost saving: This machine eliminates the cost of hydraulic oil and the trouble caused by it. There is no hard pipe or soft throat, so there is no need to cool the hydraulic oil, and the cost of cooling water is greatly reduced.

㈢. pressure

advantage

1) With air as the working medium, it is easy to obtain the working medium. The used air is discharged into the atmosphere, which is convenient for treatment. Compared with hydraulic transmission, it is not necessary to set a recovered oil tank and pipeline.

2) Because the viscosity of air is very small (about one ten thousandth of the dynamic viscosity of hydraulic oil), its loss is also very small, so it is convenient for centralized gas supply and long-distance transportation. Leakage will not pollute the environment as seriously as hydraulic transmission.

3) Compared with hydraulic transmission, pneumatic transmission has the advantages of rapid action, fast response, simple maintenance, clean working medium and no deterioration of medium.

4) The working environment has good adaptability, especially in the harsh working environment such as flammable, explosive, dusty, strong magnetic, radiation and vibration, which is superior to hydraulic, electronic and electrical control.

5) Low cost, automatic overload protection.

shortcoming

1) Due to the compressibility of air, the stability of working speed is slightly poor. However, the use of gas-liquid linkage device will get satisfactory results.

2) Due to the low working pressure (generally 0.31.0mpa) and the structural size should not be too large, the total output should not be greater than 10 ~ 40kN.

3) The noise is large, so a muffler should be added when exhausting at high speed.

4) The transmission speed of pneumatic signal in pneumatic device is slower than that of electron and light within the speed of sound. Therefore, pneumatic control system is not suitable for complex circuit with too many component stages.

㈣. hydraulic pressure

advantage

1) In terms of structure, its output power per unit weight and output power per unit size are superior to Qunfang in the four types of transmission modes, with a large torque inertia ratio. Under the condition of transmitting the same power, the hydraulic transmission device has the advantages of small volume, light weight, small inertia, compact structure and flexible layout.

2) In terms of working performance, speed, torque and power can be adjusted steplessly, with fast action response, rapid commutation and speed change, wide speed regulation range, and the speed regulation range can reach 100:1 to 2000:1; Fast action, simple control and adjustment, convenient and labor-saving operation, easy to cooperate with electrical control and connect with CPU (computer), so as to realize automation.

3) In terms of use and maintenance, the components have good self lubrication, easy to realize overload protection and pressure holding, safe and reliable; Components are easy to realize serialization, standardization and generalization.

4) All equipment using hydraulic technology has good safety and reliability.

5) Economy: hydraulic technology has strong plasticity and variability, which can increase the flexibility of flexible production and easy to change and adjust the production procedure. The manufacturing cost of hydraulic components is relatively low and has strong adaptability.

6) Hydraulic pressure is easy to be combined with new technologies such as microcomputer control to form & ldquo; Mechanical electro-hydraulic Optical & rdquo; Integration has become the trend of world development, which is convenient to realize digitization.

Disadvantages:

Everything is divided into two, and hydraulic transmission is no exception:

1) The hydraulic transmission inevitably leaks due to the relative moving surface. At the same time, the oil is not absolutely incompressible. Coupled with the elastic deformation of oil pipe, the hydraulic transmission can not obtain a strict transmission ratio, so it can not be used in the inline transmission chain of machine tools such as machining threaded gears.

2) There are edge loss, local loss and leakage loss in the process of oil flow, and the transmission efficiency is low, which is not suitable for long-distance transmission.

3) Under the condition of high and low temperature, it is difficult to adopt hydraulic transmission.

4) In order to prevent oil leakage and meet some performance requirements, the manufacturing accuracy of hydraulic components is required to be high, which brings some difficulties to use and maintenance.

5) Failure is not easy to check, especially in units where hydraulic technology is not very popular. This contradiction often hinders the further popularization and application of hydraulic technology. The maintenance of hydraulic equipment depends on experience, and it takes a long time to train hydraulic technicians.