Application of superimposed valve hydraulic system in barrel making machinery
Hydraulic system is the driving and control method commonly used in machine tool manufacturing. However, the form of control is various, and the form of fitting is also different. The commonly used forms are: tube connection, plate connection, and integrated block. Connections and newly developed superimposed valve systems. The superimposed valve is a new type of component developed on the basis of the integrated plate. When the system is composed, it does not need another connecting piece, and is directly stacked with its own valve body. Each superimposed valve can play The function of the control element acts as a channel body, and the position and number of the main oil path of the superimposed valve of each size path are the same as the reversing valve of the corresponding path, so that the stacking valve of the same path series and The reversing valves of the corresponding diameters are superimposed to form a system. The superimposed valve system has significant advantages over other forms of systems and is now compared using the table below.
Comparison of several hydraulic fitting forms
It can be seen from the above table that the superimposed integrated valve block is a new type of fitting method that overcomes many shortcomings of the tubular valve group and is developed on the basis of the plate type integrated valve group. In the stacking valve group, not only the same diameter can be used. The series of superimposed valves are superimposed as vertical superposition) to form a variety of different systems (such as work, pressure, synchronization, differential, multi-cylinder locking, sequence and other control systems) to meet the general requirements of mining, metallurgy, engineering machinery, etc. The working cycle requires, and the valve groups can be superimposed by multiple floor plates (called lateral stacking) to achieve centralized control of multiple actuators (multi-cylinder action or multi-cylinder and multiple hydraulic motors). The stacking manifold can be combined with a panel integrated board to accommodate complex systems or systems with special functional requirements as well as large systems.
Here are some examples of the application of several stacking valves in barrel making machines:
Figure 1 Hydraulic system diagram of XJY44 "three in one" barrel joint forming machine
Figure 1 shows the hydraulic schematic of the XI44 barrel joint forming machine I developed. The system is a typical example of a hydraulic system with centralized control of multiple power components. The system uses a dual-quantity vane pump (2) as a power source, and the P1 oil and P oil paths are respectively composed of an electromagnetic spill valve (10) and an external control sequence valve. (9) Set to form a two-stage pressure circuit. A check valve (6) and a special plate (7) are arranged in the extrusion cylinder circuit and the expansion cylinder circuit. Due to the action of the two valve blocks, when the working load does not reach the setting of the external control sequence valve (9) When pressure is applied, the squeeze cylinder and the expansion cylinder are operated by the dual pumps (P1 and P) simultaneously. When the system meets or exceeds the set pressure of the external control sequence valve, the pressure oil of the P1 oil passage opens the sequence valve through the external control port to automatically unload the large flow pump. At this time, the P1 oil passage and the P oil passage are automatically operated by the check valve ( 6) Separated, the cylinder is operated under a working pressure within a pressure range set by the electromagnetic spill valve (10) and varying with external resistance. At this time, almost all of the motor power is used to drive the small flow pump (P1). This quantitative pump system also takes advantage of the constant power control of the variable pump system. It is not difficult to see from the hydraulic system in Figure 1: the same name cylinder hydraulic circuit (such as the left squeeze cylinder circuit and the right squeeze cylinder circuit, the left expansion cylinder circuit and the right expansion cylinder circuit, etc.) is basically symmetrical in structure, in this In the case, when the external working resistance is not much different, and the difference in the resistance along the pipeline is not large, since the structural parameters of each cylinder are the same, the basic synchronous action of the same-named cylinder is naturally formed (when the synchronization accuracy is not high).
Another example is the lifting cylinder and the positioning cylinder circuit, because the two cylinders are much smaller than the other cylinders, and the working load is much smaller. In order to control its smooth operation, the following measures are taken: firstly The special plate cuts off the P oil circuit, and the high pressure small flow pump P1 supplies oil to it. Secondly, in order to avoid the impact of the oil cylinder during the working process, a pressure reducing valve and a throttle valve are provided in both circuits, and are accepted. While the main system supplies the pressure oil, it can also adjust its own branching pressure to reliably achieve its smooth operation.
There are three cylinders in the system: in addition to the external control sequence valve (9), the dynamic automatic unloading of the large pump P can be realized during the working process. When the machine is in the in-situ state, the electric signal is provided by the travel switch to allow electromagnetic The valves (11CT) and (12CT) are simultaneously energized, so that the electromagnetic spill valve (10) and the reversing valve (4) conduct both the P1 oil passage and the P oil passage with the O oil passage. Let the whole system unload, so that the whole machine is in standby state, reducing power loss and reducing system heating.
Figure 2 XJY49 type crimping hydraulic system diagram
Figure 2 shows the hydraulic principle of the fully hydraulically driven XJY49 crimping machine I developed. It is another typical example of using a stacking valve to control the movement of more complex machine tools.
Due to the working characteristics of the crimping machine, the hydraulic system is more complicated. The main reasons are as follows: First, the main drive system determined by the main rotating action of the drive sealing disc needs a power output with a large torque, and correspondingly it needs to be given The liquid motor provides a large pressure and flow (determined by the displacement of the hydraulic motor), so the power consumption is large.
The sealing disc drive cylinder requires a relatively large flow rate due to the large bore diameter, but the clamping force needs to be small. However, the flow rate and pressure required for the feed auxiliary cylinder and the feed wheel of the hemming wheel are small, which forms a contradiction between the flow pressure requirements of the various actuators with multiple actions. Second, due to the fact that the movement of the components is staggered in time, pressure fluctuations will occur between the circuits, causing interference between the circuits, specifically: main drive circuit (including sealing plate clamping circuit) Interference with the feed cylinder circuit (including the feed cylinder, pre-roll cylinder, crimp cylinder and crimp cylinder) and mutual interference between the feed cylinder circuits.
According to the above analysis, it is not difficult to see that the actuators of similar flow size must be arranged as a group for separate control, so that the superposition valve system can be fully utilized to be both decentralized and centrally controlled, and the main transmission system is integrated from the overall layout. Separate the system (including the auxiliary system) for control. This not only solves the contradiction between the two groups of system flow pressure difference, but also fundamentally eliminates the pressure interference between the main drive system and the feed system.
As shown in Fig. 2, the oil pump 4 is a double-quantity vane pump that drives a large system. In order to meet the hydraulic motor displacement requirements, the largest specification (20 mm diameter) superimposed valve of the current domestic superimposed valve is used in the hydraulic motor circuit, and the sealing cylinder circuit (diameter 16 mm) is laterally superimposed with the hydraulic motor circuit so that Flow control is performed on such actuators with similar flow requirements. The system pressure is set by the same electromagnetic spill valve (24) (the pressure of the two pumps is equal) and the pressure is set according to the pressure demand of the flow motor circuit when crimping. The relief valve (23) in the hydraulic motor circuit is used to prevent pressure surges generated in the circuit when the reversing valve is switched. The plate type one-way speed regulating valve (22) is used in combination with the stacking valve group, and is installed on the oil returning circuit of the hydraulic motor. The two functions are as follows: first, establish a certain back pressure; make the two parallel motors synchronously and stably rotate, second , through the speed control to control the stepless change of the speed of the liquid motor. The speed of the hydraulic motor is adjusted by two steps. The electromagnetic reversing valve (8) is used to control the combination of the two pumps or the direct unloading of the small pump to realize the two-stage speed change of the liquid motor. The stepless speed regulation of the hydraulic motor is realized by the plate type one-way speed regulating valve (22) to meet the different rotation speeds required for processing different barrel diameters. The flow and pressure of the sealing cylinder circuit are required to be low. The pressure reducing valve (20) is used to control the output pressure of the circuit; the one-way throttle valve (35) is used to control the fast forward speed of the sealing cylinder; the electric speed regulating valve (19) is used to control the working speed of the sealing cylinder; The hydraulic control check valve (39) makes the sealing of the sealing cylinder not loose during the crimping process; the plate type one-way synchronous valve 38) is combined with the stacking valve group to ensure the synchronous feeding of the sealing cylinder.
The unloading of large systems is controlled by an electromagnetic spill valve (24).
As shown in the right part of Figure 2, it is the feeding mechanism of the crimping machine and the oil control system of the feeding cylinder. The flow and pressure of each cylinder controlled by the system are similar, which is convenient for horizontal superposition and centralized control with the superposition valve. Stack valve group. The system is still powered by a dual metering pump. The low pressure, high flow P pump is controlled by an electromagnetic relief valve (28) to provide fast forward pressure oil to each feed cylinder. The high pressure oil passage P1 is controlled by a sequence valve (29) to supply a working inlet pressure oil to each feed cylinder. When the external resistance is lower than the set pressure of the electromagnetic spill valve (28), P and P1 simultaneously supply oil to the cylinder to make it fast forward; when the external resistance is higher than the electromagnetic relief valve (28), the pressure is lower than the sequence. (29) When the pressure is set, P overflows or provides fast-running pressure oil to the remaining bypasses, while the original cylinder circuit continues to provide the working pressure <oil by P1; when the original circuit cylinder works to the end of the stroke, and other bypasses When the cylinder is still running, the P1 circuit will supply pressurized oil to the remaining bypass circuits. When all the cylinders are working to the final position or the uppermost level of the plate type reversing valve in the middle of each group of stacked valves is in the neutral position, the sequence valve is opened by the self-control port, so that the P1 oil is merged into the P oil passage through the electromagnetic relief valve. (28) Overflow. The unloading link of the system is two places, one is the electromagnet power-off unloading link of the electromagnetic spill valve P iZ oil circuit, and the other is the P1 oil circuit electromagnet controlled by the plate type reversing valve (9). Link.
As shown in the feed cylinder circuit, the one-way throttle valve (25) provided on the inlet oil passage and the electric speed control valve (34) on the return oil line respectively control the fast-forward speed and the buffering speed of the feed cylinder. The other three sets of feed cylinder circuits (pre-cylinder cylinder circuit, pressure-cylinder cylinder circuit and crimping cylinder circuit) are completely symmetrical in terms of control form, and plate-type synchronous valves installed in each group of feed circuits (37) ) is to achieve the synchronous operation of the parallel cylinder of the same name; the check valve (32) can separate the low pressure P oil circuit and the high pressure P l oil circuit; the electric one-way speed control valve (30) is for control. The working speed of the feed cylinder, this outlet speed control also guarantees the stability of the feed rate when the load changes. The external control sequence throttle valve (31) is a key component for realizing the high and low speed cross feed of the three groups of cylinders without interfering with each other. Its function is: when one of the three groups of feed cylinders is entering the work process, due to the outside The function of the throttle of the sequential throttle valve (31) can avoid the influence of the other branches on the working inlet circuit when the pressure fluctuation occurs due to the rapid advance and retreat of the cylinder.
Figure 3 XJY61 compression packaging machine hydraulic system diagram
As shown in Figure 3, it is the schematic diagram of the hydraulic system of the XIY61 compression packaging machine that I developed. The system actuators are three linear motion cylinders and one rotary motion hydraulic motor. The basic working process of the compression packaging machine is: the feeding cylinder sends the workpiece (steel barrel full of material) to the working position - the squeeze cylinder squeezes the material in the barrel - exits the packing (repeated times) - after capping Entry - extrusion cylinder gland, one liquid motor rotation - crimping cylinder feed crimping - crimping cylinder out - pressure cylinder feed pressure edge, pressure side cylinder exit - liquid motor stop - extrusion The cylinder is lifted up - the feed cylinder is withdrawn.
The overall design features of the system: Due to the strict weight constraints of the system in the project task book, first of all, the system design must be compact. Second, the squeeze cylinder oil circuit must have two-stage pressure to achieve two-stage pressure-driven action of the same cylinder. Third, the rotary motion of the liquid motor and the feed cylinder are linearly interlaced, and the hydraulic motor circuit is separated from the feed cylinder circuit to supply oil in order to eliminate pressure interference. From the above points, we must pay attention to the following points when considering the scheme. The system oil pump selects the double vane pump to supply the large pump to the liquid motor, and the small pump supplies the pressure to the other cylinders. The electromagnetic spill valve (20) and the electromagnetic relief valve (14) are controlled to completely separate the two paths, and the two flow rates are also greatly different depending on the demand. As shown in the figure, in the squeeze cylinder circuit, the plate type pressure reducing valve (22) and the plate type reversing valve are used in combination with the stacking valve group, so that the squeeze cylinder is set by the overflow valve (14) during the pressing process. P1 pressure action, to achieve the force required by the indenter during the compression process; during the gland process, the pressure requirement is lower, and the P1 is decompressed through the pressure reducing valve to form the second-stage pressure. It is actually a third pressure for the entire system) to meet the force required to clamp the lid of the barrel during the sealing process. The one-way throttle valve (6) can control the forward speed of the indenter, and the three-position four-way electromagnetic reversing valve with a neutral spool function of O can keep the indenter in any desired position when jogging, and can prevent Falling due to self-weight. The pressure relay (5) allows the squeezing cylinder to return when the signal is supplied, because the squeezing cylinder has a different advance distance each time the loading amount changes, and it is impossible to position the signal by the stroke.
In the hydraulic motor circuit, the throttle valve (10) is used to control the rotational speed of the hydraulic motor. The relief valve (9) is connected in parallel between the P oil path and the O oil circuit to adjust the opening pressure thereof, so as to avoid the impact of the hydraulic motor due to inertia when the switching valve (8) is switched to stop.
The third group: the trolley cylinder, the crimping cylinder and the compression cylinder circuit are actually the combination of three sets of the same type of circuit. Here, since the three groups of cylinders are connected in the action sequence, the potential of the stacking valve is fully explored. The organic combination with the three electromagnetic reversing valves (9) makes the circuit more compact, which is a typical example of the clever application of the superposition valve in simplifying the structure. In the third set of circuits, the throttle valve 101 controls the fast forward speed of the feed cylinder, and the pressure reducing valve (24) can control the working speed of each cylinder of the circuit. The hydraulic control check valve (13) is mainly used to prevent the feed car cylinder from shifting due to oil draining during the crimping process. The superimposed valve type pressure gauge switch (16) can conveniently read the P oil pressure and P1 oil pressure value of the system and the pressure values â€‹â€‹of the A oil passage, the B oil passage and the O oil passage in the group of circuits.
It can be seen from the application examples of the above several hydraulic systems that the superposition valve does show a great advantage in the hydraulic system of the barrel machinery. In fact, in the process of product development, opening and improvement, a system has to be modified several times or even dozens of times. At this time, it is necessary to carry out multiple component additions and subtractions and reorganizations. As long as the parts are ready, apply the stacking valve. It is easy to cope with such thorny problems. It fully demonstrates the flexible configuration of the stacking valve. The engineers and technicians engaged in product development have a deep understanding of this. Finally, we believe that with the continuous development of hydraulic technology and the emergence of new components and new technologies, we will certainly make new progress in our barrel technology.
Author unit: Xi'an Machinery Research Institute
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