In the maintenance of the piston rod of the hydraulic press, it is necessary to dismantle the relevant facilities in the structure, and at the same time, deal with the fracture, and then analyze whether the piston rod can be used after processing.
In the process of processing, it is required to analyze the interface of the joint state of the rod, evenly process the distributed M 30 threaded holes, make the rod according to the special processing requirements, and then use the high-strength socket head bolts to realize the connection between the rod and the bolt. At the same time, under necessary conditions, flange connection or other welding methods can be used in the fractured area of the piston rod of the hydraulic press to further strengthen the rod.
For the nut structure of the piston rod of the hydraulic press, it is necessary to leave a gap and adjust the running accuracy of the entire system. For the cylinder structure and refueling device, as well as the related slider system, use the operation mode of the facility. The system should completely remove the air inside the rod and the pipeline. After the installation work is completed, a load test is required. The maximum eccentricity must not be exceeded during the test run or in the subsequent operation.
The repair process of the piston rod of the hydraulic press requires a comprehensive analysis of the operational failure of the piston rod and the cause of the loss. It then determines the relevant failure manifestations and troubleshooting methods.
1. Fault determination of the piston rod of the hydraulic press
The failure of the piston rod of the hydraulic press can be caused by many factors, so it is necessary to accurately determine the failure type of the piston rod. For example, during the inspection of the piston rod, it is found that the eccentricity is too large, which causes the piston rod of the hydraulic press to deform or even break during operation. Then the piston rod needs to be replaced professionally, and it can be considered whether the size of the rod is acceptable. Adjustment, thereby reducing the cost of use of the piston rod.
2. Failure analysis of hydraulic press piston rod
In the inspection of the piston rod of the hydraulic press, it is necessary to analyze the current operation comprehensiveness, so that other facilities are in an appropriate clearance state, and the piston rod is also in a stressed state, which must be used to analyze the rigid connection state of the hydraulic press slider.
If it is determined that the fault is caused by the incorrect installation position, even if the safety operation rules are followed, it is still in a state of excessive wear, and it is necessary to further study the rationality of the structural design of the rod head of the piston rod of the hydraulic press.
There are mainly four types of filters commonly used in hydraulic systems: high-pressure filters, low-pressure filters, water filters, and air filters. The following is a detailed introduction for you:
1. High-pressure filter
The high-pressure filter is installed on the high-pressure oil pipeline of the oil pump. This installation method can protect all hydraulic components except the pump, and the filtration accuracy is generally 10μm.
2. Low-pressure filter
In order to prevent the filter from working at high temperatures, it can be installed on the oil return pipeline, and the filtration accuracy is generally 20μm. This installation method cannot directly prevent impurities from entering each hydraulic component, so it cannot play a direct protective role, but it can often remove impurities in the oil, thereby indirectly protecting the hydraulic components.
3. Water filter
The water filter is installed in the water inlet pipe of the cooler, and its main function is to ensure the cleanliness of the cooling water entering the cooler.
4. Air filter
When the hydraulic system is working, the oil in the tank will discharge air from the inside to the outside when it rises, and inhale air from the outside to the inside when it falls. In order to purify the oil, an air filter is installed vertically on the fuel tank cover to filter the inhaled air; at the same time, the air filter is also an oil filling port, and new working oil is injected, which must be filtered and then enter the oil tank, so as to filter out the oil. Except for dirt particles in the oil.
In order to make the hydraulic press system and components have an ideal working life, it is necessary to control the pollution of the oil. But how? First of all, we need to reasonably configure different types of filters according to certain conditions. Here are tips about how to select hydraulic filters.
1. Inlet and outlet diameter of the hydraulic filter
The inlet and outlet diameter of the hydraulic filter should not be smaller than the inlet diameter of the matching pump, which is generally the same as the diameter of the inlet pipeline.
2. Nominal pressure of the hydraulic system
Determine the pressure rating of the filter according to the highest possible pressure in the hydraulic filter line.
3. Filter precision
The components of the hydraulic press largely determine the requirements for the filtration accuracy of the system. Therefore, when selecting the filtration precision of the hydraulic filter, the filtration precision required by the components most sensitive to cleanliness must be considered first.
4. Filter material
The material of the hydraulic filter is generally the same as that of the connected process pipeline. For different service conditions, cast iron, carbon steel, low alloy steel, or stainless steel filters can be considered.
1. Input power method
The hydraulic oil cooler is selected according to 15%~30% of the input power as the heating power of the system. The calculation of this method is often rough, without considering the volume of the fuel tank, the heat dissipation of the pump, pipeline, valve block, etc., it is generally safer to choose the larger one.
2. Empirical analogy
An analogy based on past successful experiences can save tedious calculations and conversions between different cooling unit systems. Experienced engineers have also accumulated a lot of successful experience in the selection of hydraulic oil coolers, and this method is more effective.
3. Water cooler calculation
The water cooler generally uses the heat exchange area to characterize its cooling capacity. The calculation formula of the heat exchange area is: AL=859.8Pv/(ΔT*K)
In the formula: AL--required heat exchange area, m2;
PV--fuel tank temperature rise power, kW;
ΔT--average temperature difference, °C, generally take ΔT=T1-T2, where T1--oil inlet temperature, T2--oil outlet temperature;
K--heat transfer coefficient [kW/(m2 ℃)], when the cooling water flow is small and the hydraulic oil viscosity is high, take K=200; when the general working oil is K=250; when the cooling water flow is large, the viscosity of hydraulic oil K is =350~400.
During the working process of the hydraulic press, most of the energy loss is converted into heat energy, which causes the temperature of the hydraulic oil to rise. If the oil temperature is too high, the viscosity of the hydraulic oil, the volumetric efficiency, and the working efficiency of the hydraulic system will be reduced, and even the hydraulic press will not work normally; the aging of the rubber seal will be accelerated, the service life will be shortened, and even the sealing will be lost, causing the hydraulic press system to leak seriously. Therefore, hydraulic presses often need to be equipped with industrial hydraulic oil coolers.
There are many types of industrial hydraulic oil coolers, including industrial air coolers, industrial water coolers, oil/water air coolers, industrial oil coolers, tube coolers, plate coolers, etc. The cooling capacity of the hydraulic oil cooler is expressed in a variety of unit systems, such as W/℃, Kcal/h, W, cal/s, m2, etc.
The normal working temperature of the hydraulic oil of the hydraulic press is generally 15℃~55℃. If it exceeds 55℃, it will automatically alarm to remind the user to turn on the cooler of the hydraulic press. If it exceeds 60℃ and lasts for more than 5 minutes, it will automatically stop.
Small and medium-sized hydraulic presses mostly use plate oil coolers, which are more cost-effective. Small hydraulic presses or hydraulic systems with low system power use air oil coolers or tube oil coolers. Large hydraulic presses have high power consumption, fast working speed, long pressurization stroke, and high system calorific value. They are generally equipped with industrial oil coolers, which have a good cooling effect but high costs.
The function of hydraulic filters is to filter various impurities in hydraulic systems. The main ones are mechanical impurities still remaining in the hydraulic system after cleaning, such as rust, casting sand, welding slag, iron filings, paint, paint skin, and cotton yarn crumbs, etc.; External impurities in the hydraulic system, such as oil port and dust ring and other places into the dust; The impurities produced in the working process, such as the debris formed by the hydraulic action of the seal, the colloid and carbon slag produced by the oxidation deterioration of the oil, etc.
The impurities mixed with hydraulic oil, with the circulation of hydraulic oil, will seriously affect the normal work of the hydraulic press system, such as the hydraulic components in the throttle hole and gap blockage; Damage the oil film between the parts of the hydraulic press, increase the internal leakage, reduce efficiency, increase heat, and make the oil deteriorate.
According to production statistics, more than 75% of the fault in the hydraulic system is caused by impurities mixed in the hydraulic oil, so the hydraulic filter is very important to the hydraulic system.
The following introduces the application of servo-hydraulic press:
1. Servo-hydraulic press precision parts forming:
The slider motion curve can be set according to the forming process needs, and the required pressing force can be output at any position to ensure the quality requirements of precision stamping.
2. Drawing forming process to effectively prevent breakage:
The slider movement speed can be adjusted continuously according to the needs of forming process. The design of variable slider movement speed can effectively avoid material rupture and improve the surface forming quality.
3. Forming process of new materials:
Servo hydraulic press can be used for forming magnesium alloy and other difficult materials.
4. Application of the blanking process:
The servo-hydraulic press can control the pressure output and reduce the output pressure when the material is close to fracturing, so that the blanking, cutting, and other processes can be completed without a buffer device.
5. The servo-hydraulic press can output arbitrary pressure in the whole stroke of the slider:
The slider can set any holding time at any position in the whole stroke, and the slider can be accurately positioned at any position in the whole stroke range, which can’t be realized by servo press or mechanical press.
6. Can be applied to the existing hydraulic press on all occasions:
The servo-hydraulic press has high precision, high flexibility, and a wider range of use than the existing hydraulic press.
Because of the different filtration capacities and structures, there are many kinds of filters.
The requirements for hydraulic filters are described as follows:
(1) With high, meet the requirements of ability to filter impurities, filtration accuracy (refers to the size of the impurity particles filtered) and filtration capacity (refers to the size of the flow through the filter) should meet the requirements of the system, while the resistance to liquid flow is very small;
(2) The filter material has a certain mechanical strength, not due to the effect of liquid pressure and damage;
(3) The performance should be stable at a certain working temperature;
Structure of hydraulic filters:
The general hydraulic filter is mainly composed of a filter element (or screen) and a shell (or skeleton). The flow area of the oil is formed by the countless tiny gaps or holes on the filter element. Therefore, when the impurities mixed with the oil are larger than these tiny gaps or holes, they are blocked from filtering out of the oil.
The performance characteristics of the servo-hydraulic press are as follows:
