hydraulic system
The hydraulic system is an integral part of the hydraulic equipment and is closely related to the theme machine. The design of the two is usually synchronized. The design requirements are generally based on actual conditions, paying attention to investigation and research, paying attention to the world's advanced technology, and striving to design a hydraulic system that is light in weight, small in size, high in efficiency, durable in operation, simple in structure, convenient in operation, convenient in maintenance and economical. it is good. The design steps are as follows:
First, clear design requirements
1. Host use, operation process, cycle time, work characteristics, performance indicators and operating environment requirements.
2. Hydraulic system The completed action, the form of motion, the load characteristics of the original, the stroke and speed requirements.
3, the sequence of actions, control accuracy, automation and even
Interlocking requirements.
4, control requirements Dust and cold, explosion-proof noise.
5. Efficiency Cost Economics and reliability requirements.
Second, determine the hydraulic execution of the original
1. Number of hydraulic originals Type Mounting position When considering the overall scheme of hydraulic equipment, it is determined that the hydraulic execution of the original and the overall layout of the mainframe are determined.
2. The hydraulic execution originals are:
Plunger cylinder, piston cylinder, compound speed increasing cylinder, compound boosting cylinder, multi-stage hydraulic cylinder, vane type swing cylinder, piston rack hydraulic cylinder, gear motor, cycloidal gear motor, etc.
Third, draw the hydraulic system working condition map
According to the design requirements, for the further analysis of the hydraulic system, to find out the speed change law of each hydraulic actuator in each stage of the work cycle, you can draw the relevant information of the hydraulic system.
Working condition diagram mainly includes action line diagram, speed diagram, load diagram
Fourth, system work pressure
System operating pressure is determined by equipment type, load size, structural requirements, and skill level. The system has high working pressure. The material is compact. Light weight is the development direction of the hydraulic system. At the same time, it must be properly handled to prevent leakage, noise control and reliability.
The pressure range commonly used in machine tools, die casting machines, and automobiles is less than 7Mpa.
Agricultural machinery, mining and mining vehicles, injection molding machines, marine machinery, handling machinery, engineering machinery, metallurgical machinery, common pressure range, 7~21 Mpa
Hydraulic press Excavator Heavy machinery Pressure range 21~31.5Mpa
Diamond press Pressure test machine Aircraft Hydraulic machine Common pressure range Greater than 31.5Mpa
V. Execution of original control and speed control scheme
Perform the original component, speed map and action line diagram according to the specified hydraulic pressure. Select the appropriate direction control, speed changeover, and differential connection loop to control the actuator.
The speed regulation mode is divided into stepless speed regulation and stepless speed change, and the stepless speed regulation is divided into volume speed regulation, throttle speed volume throttle speed regulation
Volumetric speed control with output torque constant high efficiency is generally suitable for high power applications
The throttle speed regulation has a simple structure, low price, moderate speed range, and is suitable for medium power applications.
Volume throttling speed regulation has large speed regulation range, high efficiency and high price, suitable for medium and small power applications.
6. Drafting the schematic diagram of the hydraulic system
The hydraulic system schematic diagram consists of three parts: hydraulic system diagram, process cycle sequence action diagram and component list.
Seven, calculate the main parameters of the actuator
Calculate the diameter of the piston rod inner diameter piston rod and the displacement of the hydraulic motor based on the hydraulic system load map and the determined system operating pressure.
Eight, choose hydraulic pump
The hydraulic pump is selected according to the measured flow rate and the system working pressure. When selecting, the rated flow rate of the pump should be equivalent to the calculated flow rate. Do not exceed too much. However, the rated pressure of the pump can be 25% higher or higher than the system working pressure.
The main types of hydraulic pumps are gear pumps, vane pumps, piston pumps, and screw pumps.
The gear pump has the characteristics of simple structure, good manufacturability, small size, convenient maintenance, long service life, low working pressure, large flow pulsation and pressure pulsation.
The vane pump has a compact structure, small size, stable operation, uniform flow, low noise, long life, but compared with this Bell, the oil pollution is more sensitive and the structure is more complicated.
Piston pumps are widely used because of their high precision, good sealing and high working pressure. However, the structure is more complicated, and the manufacturing precision is high, the price is expensive, and the oil sensitivity is high.
The screw pump has a simple structure, light weight, small flow and pressure pulsation, uniform delivery, no turbulence, little bubble generation, reliable operation, low noise and stable operation. Screw pumps are commonly used in hydraulic systems for machine tools or precision machinery.
Nine, choose hydraulic control components
Select the relevant control components such as relief valve, reversing valve, speed control valve, etc. according to the system schematic. When selecting, pay attention to the maximum working pressure and maximum flow rate of each valve in the various conditions. Under normal circumstances, the actual pressure and flow of the valve should be close to the rated value, but if necessary, the actual flow rate is allowed to exceed 20% of the rated flow. Due to reliability requirements, pressure should be used for derating. When the flow control valve is selected, its minimum stable flow rate should meet the requirements for performing the minimum operating speed of the original component.
Ten, choose the motor
In the pump specification table, the driving power of the pump under the rated working conditions (such as rated pressure, speed, displacement or flow) is generally given at the same time. The motor can be directly selected. The zone drive power can also be calculated according to the actual usage of the stupid pump.
Eleven, choose hydraulic auxiliary parts
Hydraulic accessories include accumulators, filters, fuel tank fittings, etc.
Twelve, check the performance of the hydraulic system
Many of the parameters of the hydraulic system are determined by estimation or experience. The design level needs to be judged by the performance check.
First, clear design requirements
1. Host use, operation process, cycle time, work characteristics, performance indicators and operating environment requirements.
2. Hydraulic system The completed action, the form of motion, the load characteristics of the original, the stroke and speed requirements.
3, the sequence of actions, control accuracy, automation and even
Interlocking requirements.
4, control requirements Dust and cold, explosion-proof noise.
5. Efficiency Cost Economics and reliability requirements.
Second, determine the hydraulic execution of the original
1. Number of hydraulic originals Type Mounting position When considering the overall scheme of hydraulic equipment, it is determined that the hydraulic execution of the original and the overall layout of the mainframe are determined.
2. The hydraulic execution originals are:
Plunger cylinder, piston cylinder, compound speed increasing cylinder, compound boosting cylinder, multi-stage hydraulic cylinder, vane type swing cylinder, piston rack hydraulic cylinder, gear motor, cycloidal gear motor, etc.
Third, draw the hydraulic system working condition map
According to the design requirements, for the further analysis of the hydraulic system, to find out the speed change law of each hydraulic actuator in each stage of the work cycle, you can draw the relevant information of the hydraulic system.
Working condition diagram mainly includes action line diagram, speed diagram, load diagram
Fourth, system work pressure
System operating pressure is determined by equipment type, load size, structural requirements, and skill level. The system has high working pressure. The material is compact. Light weight is the development direction of the hydraulic system. At the same time, it must be properly handled to prevent leakage, noise control and reliability.
The pressure range commonly used in machine tools, die casting machines, and automobiles is less than 7Mpa.
Agricultural machinery, mining and mining vehicles, injection molding machines, marine machinery, handling machinery, engineering machinery, metallurgical machinery, common pressure range, 7~21 Mpa
Hydraulic press Excavator Heavy machinery Pressure range 21~31.5Mpa
Diamond press Pressure test machine Aircraft Hydraulic machine Common pressure range Greater than 31.5Mpa
V. Execution of original control and speed control scheme
Perform the original component, speed map and action line diagram according to the specified hydraulic pressure. Select the appropriate direction control, speed changeover, and differential connection loop to control the actuator.
The speed regulation mode is divided into stepless speed regulation and stepless speed change, and the stepless speed regulation is divided into volume speed regulation, throttle speed volume throttle speed regulation
Volumetric speed control with output torque constant high efficiency is generally suitable for high power applications
The throttle speed regulation has a simple structure, low price, moderate speed range, and is suitable for medium power applications.
Volume throttling speed regulation has large speed regulation range, high efficiency and high price, suitable for medium and small power applications.
6. Drafting the schematic diagram of the hydraulic system
The hydraulic system schematic diagram consists of three parts: hydraulic system diagram, process cycle sequence action diagram and component list.
Seven, calculate the main parameters of the actuator
Calculate the diameter of the piston rod inner diameter piston rod and the displacement of the hydraulic motor based on the hydraulic system load map and the determined system operating pressure.
Eight, choose hydraulic pump
The hydraulic pump is selected according to the measured flow rate and the system working pressure. When selecting, the rated flow rate of the pump should be equivalent to the calculated flow rate. Do not exceed too much. However, the rated pressure of the pump can be 25% higher or higher than the system working pressure.
The main types of hydraulic pumps are gear pumps, vane pumps, piston pumps, and screw pumps.
The gear pump has the characteristics of simple structure, good manufacturability, small size, convenient maintenance, long service life, low working pressure, large flow pulsation and pressure pulsation.
The vane pump has a compact structure, small size, stable operation, uniform flow, low noise, long life, but compared with this Bell, the oil pollution is more sensitive and the structure is more complicated.
Piston pumps are widely used because of their high precision, good sealing and high working pressure. However, the structure is more complicated, and the manufacturing precision is high, the price is expensive, and the oil sensitivity is high.
The screw pump has a simple structure, light weight, small flow and pressure pulsation, uniform delivery, no turbulence, little bubble generation, reliable operation, low noise and stable operation. Screw pumps are commonly used in hydraulic systems for machine tools or precision machinery.
Nine, choose hydraulic control components
Select the relevant control components such as relief valve, reversing valve, speed control valve, etc. according to the system schematic. When selecting, pay attention to the maximum working pressure and maximum flow rate of each valve in the various conditions. Under normal circumstances, the actual pressure and flow of the valve should be close to the rated value, but if necessary, the actual flow rate is allowed to exceed 20% of the rated flow. Due to reliability requirements, pressure should be used for derating. When the flow control valve is selected, its minimum stable flow rate should meet the requirements for performing the minimum operating speed of the original component.
Ten, choose the motor
In the pump specification table, the driving power of the pump under the rated working conditions (such as rated pressure, speed, displacement or flow) is generally given at the same time. The motor can be directly selected. The zone drive power can also be calculated according to the actual usage of the stupid pump.
Eleven, choose hydraulic auxiliary parts
Hydraulic accessories include accumulators, filters, fuel tank fittings, etc.
Twelve, check the performance of the hydraulic system
Many of the parameters of the hydraulic system are determined by estimation or experience. The design level needs to be judged by the performance check.
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Hydraulic orbit motors & hydraulic steering unit are our core products.
At present, most popular Brands in Hydraulics are Danfoss, Char Lynn, M+S, HANJIU, each with its own merits, however
the reason why more and more clients choose HANJIU is because it has obvious advantages over other brands in terms of delivery, service, quality and profit rate.
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Shijiazhuang Hanjiu Technology Co.,Ltd
Director hanhan // E-mail: manager@sjzhjsm.com // Skype: Simon-Hanjiu Hydraulics // WhatsApp: +86 18903213886 Website: http://www.hjhydraulic.com
Director hanhan // E-mail: manager@sjzhjsm.com // Skype: Simon-Hanjiu Hydraulics // WhatsApp: +86 18903213886 Website: http://www.hjhydraulic.com
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