Analysis of hydraulic and pneumatic systems of GMGT1 through-type grinding machine Xu Genhua 1 (Lianyungang Leather Machinery Factory, Lianyungang 222069) analysis, proposed solutions for hydraulic and pneumatic failures in use. Rumors of leather machinery and machinery in other industries In the same way, the degree of automation continues to increase. In the late 1980s and 1990s, most of the domestic leather machinery used traditional mechanical transmission. Taking the leather machine as an example, the axial swing of the grinding roller is mechanical structure-one eccentric worm gear. The structure, the eccentric amount and the swing frequency can not be adjusted; the leather feed is required by the operator to pedal on the pedal through the lever mechanism, and the operator has great labor intensity and low efficiency. In the early and mid-1990s, some advanced leather machinery products adopted frequency conversion speed regulation. Because leather factories generally have poor voltage stability in relatively remote areas, they sometimes affect the normal operation of the frequency converter. In the middle and late 1990s, some leather machinery products adopted advanced hydraulic transmission and pneumatic control technology, which made the operation more convenient and labor-saving, and the operation was more reliable and more efficient.
1GMGT1 leather machine hydraulic system analysis GMGT1 grinding machine is the most advanced and most automatic grinding equipment in domestic grinding machine. The hydraulic system of the machine is steplessly adjustable.
1.1 The working principle of the hydraulic system is the hydraulic principle diagram of the GMGT1 type leather machine. The axial swing of the grinding roller is realized by the hydraulic motor 1. The rotation of the feeding roller is driven by the hydraulic motor 2 to drive the rated working pressure of the hydraulic system to 6.3 MPa. When the actual working pressure is about 4 MPa, the motor drives the vane pump to handle the fault processing method. Motor oil leakage replacement motor seal check overflow valve 1 and relief valve 2 set pressure is correct. Motor does not turn. Check if throttle valve and speed control valve are open. Check if the grinding roller and feed roller are stuck. Coupling wear condition Motor speed is unstable Check whether the oil temperature exceeds 60C. If it exceeds the use of the cooler cooling oil for more than half a year, if the hydraulic oil is replaced by a new hydraulic oil, the drive motor 1 rotates, then The oil is divided into two ways, one way through the throttle speed regulating valve and the overflow valve 2 back to the oil tank; the other way through the electromagnetic reversing valve, the driving motor 2 returns to the oil tank through the speed regulating valve, if the feeding roller exits, the solenoid valve is transposed The oil is directly returned to the tank through the electromagnetic reversing valve. The set working pressure of the relief valve 1 is 4 MPa, and the set working pressure of the relief valve 2 is 1.2. The vane pump of the characteristic quantity of the hydraulic system supplies the working hydraulic oil of two tandem cycloidal motors. In order to achieve independent adjustment of the speed of the motor 1 and the motor 2, the motor 1 that is driven by the grinding roller is less loaded by connecting an oil circuit at the outlet of the motor 1, and the motor inlet and outlet pressure difference is 8 MPa, and the rotation speed is 60150 rpm. It is steplessly adjustable; when the motor 2 that drives the feed roller is working, the maximum load is 20MPa, and the rotation speed is 0~60 rpm, which is steplessly adjustable. Therefore, the motor 1 that drives the grinding roller is used as the first stage to ensure It has a corresponding rotation speed; because the rotation speed of the motor 2 is low, the excess hydraulic oil flows back to the fuel tank through the bypass to control the opening degree of the throttle valve provided on the bypass to achieve the purpose of the motor 1 to adjust the speed of the motor 2 The speed regulation is realized by a speed regulating valve which is arranged at the outlet oil path of the motor 2, and aims to generate a back pressure to make the motor 2 run more smoothly. 3 Hydraulic system failure and solution The hydraulic system The control circuit adopts a fully sealed superimposed valve structure, which can work stably in a poor environment, with high reliability and few failures. General faults and solutions are shown in Table 1. 2GMGT1 grinding machine pneumatic principle and analysis Pneumatic control of the working medium is compressed air, no pollution to the environment, so pneumatic control is widely used in the automatic control of mechanical equipment, compressed air working pressure More than 0.7MPa, so the automatic control is mostly used in the automatic control system with little force.
2.1 GMGT1 leather machine pneumatic principle principle diagram work, the air compressor will send compressed air (pressure 0.6~0.7MPa) into the gas source processing triple unit set on the leather machine, 4 channels independently control 4 actions : Feeding roller advance and retreat, cover opening and closing, pressing plate opening and closing, and grinding roller braking air source processing triple joint function is to perform compressed air such as water gas separation, pressure regulation and lubrication lubrication cylinder and other actuators.
2.2 Pneumatic system characteristics From the pneumatic schematic diagram, it can be seen that the pneumatic transmission is different from the hydraulic transmission. There is no need to set up the return air circuit. The compressed air after the work is completed can be directly drained. The double-acting cylinder adopts the two-position five-way electromagnetic reversing valve. The working cylinder adopts two-position three-way electromagnetic reversing valve, and the cylinder for controlling the opening and closing of the cover needs to be smooth and shock-free, so that the throttle valve with a gentle degree of adjustment is provided at the air outlet; when the feeding roller advances and retreats the cylinder, the leather is required to be fed. The action is slower and the action is faster when exiting. Therefore, two one-way throttle speed regulating valves are provided to control the speed of the feed roller in and out. 23 Pneumatic system failure analysis The pneumatic system uses high quality pressure resistant plastic pipe and high quality plug-in type. The joint is quick and reliable to disassemble and is not easy to leak. The main fault is that the cylinder leaks after a long time of use, and the cylinder seal can be replaced.
(: 2000-01-14 Editor: Zhu Xi proofread: Wu Qi)
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