What is the working principle of hydraulic injection molding machine?

Hydraulic transmission.

It is the hydraulic oil as the working medium, through the power element (oil pump) the mechanical energy of the prime mover into hydraulic oil pressure energy, and then through the control element, and then with the help of the implementation element (oil cylinder or oil motor) will convert the pressure energy into mechanical energy, drive the load to achieve linear or rotary motion, and through the remote control of the control element manipulation and adjustment of the flow, adjusting the force and speed of the implementation element.

When the outside world has a disturbance to the above system, the output of the actuator generally deviates from the original adjustment value, resulting in a certain error hydraulic control: and hydraulic transmission, the system also includes power elements, control elements and actuators, but also through the oil transfer of power.

The difference between the two is that the hydraulic control has a feedback device, the role of the feedback device is the output of the actuator (displacement, speed, force and other mechanical quantities) feedback back to the input (can be changed, can also be constant) for comparison, with the compared deviation to control the system, so that the output of the actuator with the change in the input or to maintain a constant. It is a hydraulic transmission system that constitutes a closed-loop circuit, also called a hydraulic follower system or hydraulic servo system.

The hydraulic transmission system is used in the on-off or logic control element, in terms of its control purpose, is to maintain the stability of the adjusted value or simply change the direction, also called the fixed value and sequence control element.

The hydraulic control system is used in the servo control element, with feedback structure, and control with electrical devices, there is a high control accuracy and response speed, the controlled pressure and flow rate often change continuously. The output power can be amplified.

Proportional control is a control between the above two, the proportional control valve is used in the on-off control elements and servo control elements based on the development of a new type of electric - hydraulic control elements, both the above two types of components with some of the characteristics of the hand-adjusted on-off control can not meet the requirements, but also does not require a servo valve on the hydraulic system as strict pollution control requirements of the occasion.

Hydraulic drive system advantages and disadvantages

In the current four major types of transmission (mechanical, electrical, hydraulic and pneumatic), no power transmission is perfect, and hydraulic transmission has the following extremely obvious advantages.

From the structural point of view, its output power per unit weight and output power per unit size in the four types of transmission is the force of the group, there is a large torque inertia ratio, in the case of transmission of the same power, the hydraulic transmission device is small, lightweight, small inertia, compact structure, flexible layout.

From the work performance, speed, torque, power can be steplessly adjusted, fast action responsiveness, can quickly change direction and speed, wide speed range, speed range up to 100:l to 2000:1; good action speed, control, adjustment is relatively simple, more convenient manipulation, labor-saving, easy to match with the electrical control, as well as the connection with the CPU (computer), easy to achieve automation.

From the point of view of use and maintenance, the self-lubrication of the components is good, easy to achieve overload protection and pressure retention, safe and reliable; components are easy to achieve serialization, standardization, generalization. All the equipment using hydraulic technology has good safety and reliability.

From the economic cost point of view: hydraulic technology is very plastic and variable, can increase the flexibility of flexible production, and is easy to change and adjust the production process, hydraulic components are relatively speaking not high manufacturing costs, adaptability is relatively strong. Hydraulic easy to combine with new technologies such as microcomputer control, constituting a "machine-electric-hydraulic-optical" integration has become the world trend of development, to facilitate the realization of digital.
 

Hydraulic transmission disadvantages.

Everything is divided into two, hydraulic transmission is no exception.

Hydraulic transmission because of the relative movement of the surface inevitably exists leakage, while the oil is not absolutely incompressible, coupled with the elastic deformation of the oil pipe, hydraulic transmission can not get a strict ratio, and therefore can not be used in the inline transmission chain, such as processing of threaded gears and other machine tools.

Oil flow process along with the loss, local loss and leakage loss, transmission efficiency is low, not suitable for long-distance transmission.

In high and low-temperature conditions, the use of hydraulic transmission has certain difficulties.

In order to prevent oil leakage and to meet certain performance requirements, hydraulic components manufacturing precision requirements, to the use and maintenance of certain difficulties.

Failure is not easy to check, especially in units where hydraulic technology is not very popular, this contradiction often hinders the further promotion and application of hydraulic technology. Hydraulic equipment maintenance needs to rely on experience, the time required to train hydraulic technicians is long.