An electro-hydraulic control system for workpiece indexing and its implementation method

Abstract

This invention discloses a workpiece indexing electro-hydraulic control system and its implementation method, relating to the technical field of advanced manufacturing production lines. The system includes a hydraulic control system and an electrical control system. Through combined electro-hydraulic control, it completes the logical sequence control of the translation and lifting of heavy workpieces. The system has functions such as automatic cycle, single cycle, hydraulic cylinder reset, and emergency stop. The system has the characteristics of simple structure, good economy, high reliability, and easy maintenance, making up for the shortcomings of industrial robots, manipulators, pneumatic systems and other technical means.

Description

Technical Field

[0001] This invention belongs to the technical field of electro-hydraulic control system for workpiece indexing on advanced manufacturing production lines, and specifically discloses the workpiece indexing electro-hydraulic control system and its implementation method. Background Technology

[0002] With the widespread application and empowerment of information, network, and intelligent technologies, a large number of industrial robots and intelligent process control equipment are embedded in modern advanced manufacturing continuous or semi-continuous production lines, such as those used in the processing and manufacturing of automotive parts. This has greatly improved production efficiency and reduced labor intensity. Because production lines are designed with space constraints in mind, they need to be expanded in three-dimensional space. For some heavier workpieces, adjacent processing equipment is not on the same plane, requiring spatial repositioning. Conventional mechanical repositioning or pneumatic systems cannot withstand large loads and pose potential risks of instability and reliability. While industrial robots can achieve flexible control, their high cost and large space occupation make them less than ideal in this situation. Hydraulic systems, on the other hand, have advantages such as heavy load capacity, simple structure, good stability, low cost, and convenient control, solving the repositioning requirements for heavier workpieces. Summary of the Invention

[0003] This invention provides a workpiece indexing electro-hydraulic control system and its implementation method. The invention consists of a hydraulic control system and an electrical control system. The hydraulic system employs a dual-cylinder layout to respectively achieve the translation and lifting requirements during workpiece indexing. The electrical control system assists the hydraulic system in completing functions such as automatic cycle, single cycle, hydraulic cylinder reset, and emergency stop. Through the electrical control circuit, two dual-electro-controlled three-position four-way solenoid directional valves control the movement of the two hydraulic cylinders according to a work cycle: hydraulic cylinder 1A advances, reaches its working position, and stops; hydraulic cylinder 2A advances, reaches its working position, and stops; hydraulic cylinder 2A quickly retracts, reaches its working position, and stops; hydraulic cylinder 1A quickly retracts, reaches its working position, and stops. This achieves logical sequence control, ensuring reliable and stable operation, and overcoming the shortcomings of other technologies such as industrial robots, robotic arms, and pneumatic systems.

[0004] This invention provides a hydraulic control system comprising an independent integrated oil tank, a hydraulic pump assembly, a safety relief valve, a pressure gauge, a return oil filter, a check valve, a dual-electro-controlled solenoid directional valve (O-type), a one-way throttle valve, a double-acting hydraulic cylinder, a limit switch, and auxiliary pipeline joints. The hydraulic system consists of a main oil circuit and two branch oil circuits. The main oil circuit is connected to the high-pressure port of the hydraulic pump, and the oil enters the inlet of the check valve. The outlet of the check valve supplies pressurized oil to the two branch circuits through a three-way connector. The oil is then connected to the P port of the solenoid directional valve through pipelines and connectors. In the first branch circuit, the working port A of the three-position four-way solenoid directional valve is connected to the inlet of the one-way throttle valve, and the outlet of the one-way throttle valve is connected to the rodless chamber of hydraulic cylinder 1A. The working port B of the three-position four-way solenoid directional valve is connected to the rod chamber of hydraulic cylinder 1A. The piston rod of the hydraulic cylinder is equipped with a limit switch sensing block at the front end, which can trigger the action of limit switches S11 and S12. Similarly, the connection method of the hydraulic components in the second branch circuit is similar to that of the first branch circuit. The T ports of the solenoid directional valves in the two branches are connected to the return oil filter inlet through the return oil pipeline via a three-way connector. The outlet of the return oil filter is connected to the return oil port of the hydraulic oil tank.

[0005] Furthermore, in the aforementioned hydraulic circuit, a relief valve is connected in parallel to the high-pressure oil outlet of the hydraulic pump. This valve is mainly used to set the system working pressure and to ensure safe overflow after system overload, thus preventing damage to the hydraulic pump.

[0006] Furthermore, in the aforementioned hydraulic circuit, a check valve is installed between the hydraulic pump and the three-position four-way solenoid directional valve to prevent high-pressure oil from flowing back into the hydraulic pump under overload impact conditions, thus preventing hydraulic pump failure.

[0007] Furthermore, in the above circuit, a dual-electrically controlled three-position four-way solenoid directional valve is used. Its center position function is O-type, with bidirectional centering spring reset. When the valve is stopped, the valve core is in the middle position, and the circuit between the working oil ports A and B and the hydraulic cylinder is completely closed. The high-pressure oil at port P is unloaded through the relief valve, and port T is connected to the return oil. In this case, both chambers of the hydraulic cylinder are filled with high-pressure oil, which has good rigidity and can ensure that the load workpiece is stably stationary.

[0008] Furthermore, in the above circuit, a one-way throttle valve is installed between the three-position four-way solenoid directional valve and the hydraulic cylinder on the two branches. The oil inlet flow rate is adjusted by the valve, thereby controlling the speed of hydraulic cylinders 1A and 2A during the working stroke to meet the working rhythm of the production line. When the hydraulic cylinder returns, the oil returns through the one-way valve of the one-way throttle valve. At this time, the throttling function fails, thereby realizing the quick return function of the hydraulic cylinder.

[0009] Furthermore, in the above circuit, the position and stroke of the piston rods of hydraulic cylinders 1A and 2A are controlled by four limit switches S11, S12, S21, and S22. The electrical interlock formed by the logic circuit in the combined electrical control system controls the four sets of coils 1Y1, 1Y2, 2Y1, and 2Y2 of the two three-position four-way solenoid directional valves, thereby realizing the sequential action control of hydraulic cylinders 1A and 2A.

[0010] The electrical control circuit provided by this invention comprises a 24V DC power supply, a working mode selection switch SB0, a start switch SB1, a stop switch SB2, a reset switch SB3, an emergency stop switch EB, intermediate relays KA1, KA2, and KA3, limit switches S11, S12, S21, and S22, and three-position four-way solenoid valve solenoid coils 1Y1, 1Y2, 2Y1, and 2Y2. This circuit has hydraulic cylinder reset, single cycle mode, automatic cycle mode, and emergency stop function.

[0011] Furthermore, the hydraulic cylinder reset control function is to prevent the two hydraulic cylinders from failing to reach their positions due to a previous emergency stop or shutdown after system startup, which could lead to erratic movements, accidents, and malfunctions. Therefore, after the system is powered on, the hydraulic cylinders need to be reset to their initial positions. By using the reset button switch SB3, branches 15, 16, 17, and 18 in the electrical control circuit are connected, energizing the solenoid coils 1Y2 and 2Y2 of the three-position four-way solenoid directional valve and the relay coils KA2 and KA3. Hydraulic cylinders 1A and 2A quickly return to their initial positions, completing the reset.

[0012] Furthermore, the single-cycle working mode of the hydraulic cylinder is achieved by setting the working mode conversion switch SB0 to the right position and pressing the start switch SB1, which completes the working advance and stop of hydraulic cylinder 1A, the working advance and stop of hydraulic cylinder 2A, the rapid retraction and stop of hydraulic cylinder 2A, and the rapid retraction and stop of hydraulic cylinder 1A.

[0013] Furthermore, the automatic cycle mode of the hydraulic cylinder is achieved by setting the mode switch SB0 to the left position and pressing the start switch SB1. Hydraulic cylinder 1A advances and stops at the working position, hydraulic cylinder 2A advances and stops at the working position, hydraulic cylinder 2A quickly retracts and stops at the working position, and hydraulic cylinder 1A quickly retracts and stops at the working position. After stopping, the above actions are repeated automatically until the stop switch SB2 or the emergency stop button EB is pressed, at which point the system stops.

[0014] The present invention has the following beneficial effects:

[0015] 1. A workpiece indexing electro-hydraulic control system and its implementation method can effectively realize automatic cycle, single cycle, hydraulic cylinder reset, and emergency stop functions;

[0016] 2. The electro-hydraulic control system can complete the rotation of heavy workpieces and can make up for the shortcomings of certain workstations on advanced mechanical manufacturing production lines where industrial robots, manipulators, and pneumatic systems are not suitable.

[0017] 3. This system can be adjusted via a one-way throttle valve to control the speed of the hydraulic cylinder and meet the production line cycle adjustment requirements;

[0018] 4. This system uses a three-position four-way solenoid directional valve with an O-type center position function, which provides good system rigidity and stability;

[0019] 5. The entire system has a simple structure, low cost, high reliability, and is easy to maintain.

[0020] In summary, this system, through electro-hydraulic control and electrical interlocking logic control, meets the requirements for the rotation of heavier workpieces on the production line, enables the selection of multiple operating modes and the adjustment of different cycle times, and can be effectively embedded into automated production lines to fulfill production requirements. Attached Figure Description

[0021] Figure 1 Hydraulic control system;

[0022] Figure 2 Electrical control system;

[0023] Figure 3 Workpiece indexing flowchart;

[0024] Icons: Hydraulic pump 0Z1; Relief valve 0V1; Pressure gauge 0Z2; Return oil filter 0V3; Check valve 0V2; Three-position four-way solenoid directional valve (O-type) 1V1; Three-position four-way solenoid directional valve (O-type) 2V1; Solenoid coil 1Y2; Solenoid coil 2Y1; Solenoid coil 2Y2; High-pressure oil port P; Return oil port T; Working oil port A; Working oil port B; One-way throttle valve 1V2; One-way throttle valve 2V2; Hydraulic cylinder 1A; Hydraulic cylinder 2A; Limit switch S11; Limit switch S12; Limit switch S21; Limit switch S22; DC power supply 24V; Changeover switch SB0; Start switch SB1; Stop switch SB2; Emergency stop switch EB; Reset switch SB3; Relay KA1; Relay KA2; Relay KA3. Implementation

[0025] In view of this, the core of the present invention is to provide a workpiece indexing electro-hydraulic control system, which enables two hydraulic cylinders to operate in a preset sequence, thereby completing the workpiece translation and lifting indexing actions.

[0026] Another core aspect of this invention lies in providing an electro-hydraulic control method, which features two hydraulic cylinder reset, single-cycle mode, automatic cycle mode, and emergency stop function.

[0027] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Please refer to Figure 1 and Figure 2 When the hydraulic pump 0Z1 starts, the high-pressure oil passes through the connector and pipeline system and enters the relief valve 0V1 and check valve 0V2 through the three-way connector. The relief valve 0V1 can be adjusted according to the system requirements to set the safe working pressure of the hydraulic system. The pressure is displayed and read by the pressure gauge 0Z2. The main oil circuit supplies oil to the pressure port P of the three-position four-way solenoid directional valves 1V1 and 2V1 through the check valve 0V2, the three-way connector and pipeline respectively. At this time, the valve cores of the three-position four-way solenoid directional valves 1V1 and 2V1 are in the neutral position under the action of the return spring. P, T, A and B cannot be in the disconnected state. The two translation lifting hydraulic branches cannot form a circuit. The hydraulic cylinders 1A and 2A remain stationary in the position when they stopped last time.

[0029] When performing a hydraulic cylinder reset operation, the purpose is to ensure the system's safety and reliability during operation. Hydraulic cylinders 1A and 2A need to be returned to their initial leftmost position. First, press the reset switch SB3. Figure 2 Electrical circuits 15 and 17 are open, which in turn leads to electrical circuits 9 and 12. Relays KA2 and KA3 coils are energized, which in turn keeps electrical circuits 16 and 18 open. The solenoid coils 2Y2 and 1Y2 of the three-position four-way solenoid directional valves 1V1 and 2V1 are simultaneously energized, causing directional valves 1V1 and 2V1 to operate in the right position. Pressure port P is simultaneously connected to working port B, and return port T is connected to port A. Pressure oil simultaneously flows into the right-hand oil circuit, entering both the translation hydraulic cylinder 1A and the lifting hydraulic cylinder. Hydraulic oil in the rodless chambers of translation cylinder 1A and lifting cylinder 2A enters port A through the one-way valves of one-way throttle valves 1V2 and 2V2, flows through the valve cores of solenoid directional valves 1V1 and 2V1, flows from port T through the pipeline to the return oil filter 0V3, and then flows back to the oil tank through the pipeline, thus forming a passage. When the piston rods of translation cylinder 1A and lifting cylinder 2A retract, and the piston rods touch the limit switches S11 and S21, the normally closed contacts of the limit switches actuate, disconnecting the flow. Figure 2 In the electrical circuits 9 and 12, the solenoid coils 2Y2 and 1Y2 of the three-position four-way solenoid directional valves 1V1 and 2V1 are simultaneously de-energized. The solenoid directional valves 1V1 and 2V1 rely on the return spring to return the valve core to the neutral position. The pressure oil port P, the return oil port T, and the working oil ports A and B are all cut off. The translation circuit and the lifting circuit in the hydraulic system cannot form a path. The translation hydraulic cylinder 1A and the lifting hydraulic cylinder 2A stop at the same time and are locked, thus completing the reset of the two hydraulic cylinders.

[0030] When in single-cycle operating mode, press Figure 2After switching switch SB0 is activated, the switch is in the right position. Pressing start switch SB1 closes the normally closed contact of relay KA3, creating a circuit in electrical circuit 3. Relay KA1 is energized, creating a circuit in electrical circuit 4. The solenoid coil 1Y1 of solenoid directional valve 1V1 is energized, causing the valve core of solenoid directional valve 1V1 to move to the left position. The pressure oil port P and working oil port A are the same, and port B and return oil port T are the same. The pressure oil enters the throttling section of one-way throttle valve 1V2 (the one-way valve is not working at this time) through the pipeline and enters the rodless chamber of hydraulic cylinder 1A. The rod chamber of 1A is connected to port B of the solenoid directional valve through the pipeline, passing through the valve core oil circuit. The oil enters through port T, connects to the return oil filter 0V3 via a pipeline, and then returns to the oil tank. This forms a complete hydraulic circuit. The piston rod of hydraulic cylinder 1A extends, pushing the workpiece in a translational motion. When the piston rod reaches the limit switch S12, its normally closed contact opens, the electrical control circuit 4 is disconnected, the solenoid coil 1Y1 is de-energized, and the solenoid directional valve 1V1, under the action of the return spring, returns its valve core to the neutral position. All ports P, A, B, and T of the directional valve 1V1 are closed, the hydraulic translational branch is disconnected, and the piston rod of hydraulic cylinder 1A stops moving, completing the workpiece translation. Simultaneously, the limit switch S12 is energized, and its normally open contact closes. Figure 2Electrical circuit 7 is completed, energizing electromagnetic coil 2Y1. Electromagnetic directional valve 2V1 operates in the left position, with pressure port P matching port A and return port T matching port B. Similar to the aforementioned translation hydraulic branch, the lifting hydraulic branch is completed, pushing out the piston rod of hydraulic cylinder 2A to lift the workpiece. When the piston rod touches limit switch S22, its normally closed contact opens, circuit 7 is disconnected, electromagnetic coil 2Y1 is de-energized, and the valve core of electromagnetic directional valve 2V1 returns to the neutral position under the action of the return spring. Ports P, A, T, and B are in the cut-off state, the hydraulic lifting branch is disconnected, and the piston rod of hydraulic cylinder 2A stops, completing the workpiece lifting. Furthermore, the normally open contact of limit switch S22 closes, completing electrical circuit 9 and energizing electromagnetic coil 2Y2. When solenoid directional valve 2V1 is in the right position, oil ports P and B are connected, forming a circuit. The rod chamber of hydraulic cylinder 2A returns to the oil tank through the check valve in one-way throttle valve 2V2, causing the piston rod of hydraulic cylinder 2A to retract rapidly. When the piston rod touches limit switch S21, its normally closed contact opens, electrical circuit 9 is disconnected, solenoid coil 2Y2 is de-energized, solenoid directional valve 2V1 returns to the middle position, hydraulic lifting branch is disconnected, and the piston rod of hydraulic cylinder 2A stops, completing the rapid retraction. Further, the normally open contacts of limit switches S21 and S12 close, electrical circuit 12 is formed, relay KA3 is energized, electrical circuit 13 remains open, solenoid coil 1Y2 of solenoid directional valve 1V1 is in the right position. Oil ports P and B are connected, forming a closed circuit. The hydraulic oil in the rod chamber of hydraulic cylinder 1A returns to the oil tank through the check valve in the one-way throttle valve 1V2, causing the piston rod of hydraulic cylinder 1A to retract rapidly. When the piston rod touches the limit switch S11, its normally closed contact opens, the electrical circuit 12 is disconnected, the solenoid coil 1Y2 is de-energized, the solenoid directional valve 1V1 returns to the intermediate position, the hydraulic lifting branch is disconnected, and the piston rod of hydraulic cylinder 1A stops, completing the rapid retraction. This achieves the sequential control of hydraulic cylinder 1A translational feed, hydraulic cylinder 2A lifting feed, hydraulic cylinder 2A rapid retraction, and hydraulic cylinder 1A rapid retraction, completing one work cycle.

[0031] When in automatic cycle mode Figure 2 When the selector switch SB0 is in the left position, pressing the start switch SB1 opens electrical circuit 2, energizing and maintaining relay KA1. Similar to the single-cycle operation described above, electrical circuits 4, 7, 9, and 12 sequentially open, completing the sequential control of hydraulic cylinder 1A's translational feed, hydraulic cylinder 2A's lifting feed, hydraulic cylinder 2A's rapid retraction, and hydraulic cylinder 1A's rapid retraction. After one cycle is completed, the above electrical circuit on / off sequence is repeated to complete the automatic cycle operation until it needs to be stopped. Pressing the stop switch SB2 stops the system, and hydraulic cylinders 1A and 2A remain stopped. The three-position four-way solenoid valves 1V1 and 2V1 are locked in the middle position by the O-type function, reliably keeping the hydraulic cylinders stationary.

[0032] Preferably, in the event of an accident, pressing the emergency stop switch EB will immediately stop the entire hydraulic and electrical control system to prevent an accident from occurring.

[0033] Preferably, by adjusting the overflow valve 0V1, a reasonable system working pressure can be set for different loads.

[0034] Preferably, by adjusting the opening of the one-way throttle valves 1V2 and 2V2, the speed at which the piston rods of hydraulic cylinders 1A and 2A drive the workpiece to translate and lift can be adjusted to meet the production cycle time.

[0035] Preferably, the three-position four-way solenoid directional valves 1V1 and 2V1 in the hydraulic system adopt an O-type structure with a neutral position function. When the valve core is in the neutral position, the oil ports P, T, A, and B are locked. The two chambers of hydraulic cylinders 1A and 2A are filled with high-pressure oil, which has good rigidity and helps to maintain high reliability when hydraulic cylinders 1A and 2A stop, preventing the piston rod from creeping under the load of the workpiece.

[0036] Preferably, the four sets of coils 1Y1, 1Y2, 2Y1, and 2Y2 of the two three-position four-way solenoid directional valves are controlled by an electrical interlock formed by the logic combination of limit switches S11, S12, S21, and S22, thereby realizing the sequential control of the hydraulic cylinders.

[0037] In the description of this application, it should be noted that the terms "center," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] Unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "communication" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, pipeline connections, or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A workpiece indexing electro-hydraulic control system, characterized in that, Including hydraulic control systems and electrical control systems; The hydraulic control system comprises an independent integrated oil tank, a hydraulic pump assembly, a safety relief valve, a pressure gauge, a return oil filter, a check valve, a dual-electro-controlled three-position four-way solenoid directional valve, a one-way throttle valve, a double-acting hydraulic cylinder, limit switches, and auxiliary pipeline joints. The hydraulic system consists of a main oil circuit and two branch oil circuits. The main oil circuit is connected to the high-pressure port of the hydraulic pump, and the oil enters the inlet of the check valve. The outlet of the check valve supplies pressurized oil to the two branch circuits via a three-way connector, and is connected to the P port of the solenoid directional valve through pipelines and connectors. On the first branch circuit, the three-position four-way solenoid valve... The working port A of the directional control valve is connected to the inlet of the one-way throttle valve, and the outlet of the one-way throttle valve is connected to the rodless chamber of hydraulic cylinder 1A. The working port B of the three-position four-way solenoid directional control valve is connected to the rod chamber of hydraulic cylinder 1A. The piston rod of the hydraulic cylinder is equipped with a limit switch sensing block at the front end, which triggers the action of limit switches S11 and S12. Similarly, the connection method of the hydraulic components in the second branch is similar to that of the first branch. The T ports of the two branch solenoid directional control valves are respectively connected to the return oil through the return oil pipeline to the inlet of the return oil filter via a three-way connector. The outlet of the return oil filter is connected to the return oil port of the hydraulic oil tank. The electrical control system comprises a 24V DC power supply, a working mode selection switch SB0, a start switch SB1, a stop switch SB2, a reset switch SB3, an emergency stop switch EB, intermediate relays KA1, KA2, and KA3, limit switches S11, S12, S21, and S22, and three-position four-way solenoid valve solenoid coils 1Y1, 1Y2, 2Y1, and 2Y2.

2. The workpiece indexing electro-hydraulic control system according to claim 1, characterized in that: The hydraulic system adopts a dual hydraulic cylinder layout to realize the translation and lifting requirements during the workpiece rotation process. The electrical control system assists the hydraulic system in completing automatic circulation, single circulation, hydraulic cylinder reset, and emergency stop functions. The reset control function is used after system startup to prevent the two hydraulic cylinders from malfunctioning due to a previous emergency stop or shutdown, which could lead to accidents and malfunctions. Therefore, after the system is powered on, the hydraulic cylinders need to be reset to their initial positions. By using the reset button switch SB3, branches 15, 16, 17, and 18 in the electrical control circuit are connected, energizing the solenoid coils 1Y2 and 2Y2 of the three-position four-way solenoid directional valve and the relay coils KA2 and KA3. Hydraulic cylinders 1A and 2A quickly return to their initial positions, completing the reset. The single-cycle working mode is achieved by setting the working mode conversion switch SB0 to the right position and pressing the start switch SB1, which completes the following steps: hydraulic cylinder 1A advances and stops at the working position, hydraulic cylinder 2A advances and stops at the working position, hydraulic cylinder 2A retracts and stops at the working position, and hydraulic cylinder 1A retracts and stops at the working position. The automatic cycle operating mode is achieved by setting the operating mode switch SB0 to the left position and pressing the start switch SB1. Hydraulic cylinder 1A advances and stops when it reaches its working position, hydraulic cylinder 2A advances and stops when it reaches its working position, hydraulic cylinder 2A quickly retracts and stops when it reaches its working position, and hydraulic cylinder 1A quickly retracts and stops when it reaches its working position. The cycle continues until the stop switch SB2 or the emergency stop button EB is pressed, at which point the system stops operating.

3. The workpiece indexing electro-hydraulic control system according to claim 1, characterized in that: The valve adopts a dual-electrically controlled three-position four-way solenoid directional valve. Its center position function is O-type, with bidirectional centering spring reset. When the valve is stopped, the valve core is in the middle position, and the circuit between the working oil ports A and B and the hydraulic cylinder is completely closed. The high-pressure oil at port P is unloaded through the relief valve, and port T is connected to the return oil. In this case, both chambers of the hydraulic cylinder are filled with high-pressure oil, which can ensure that the load workpiece is stably stationary.

4. The workpiece indexing electro-hydraulic control system according to claim 1, characterized in that: The electrical interlock formed by the logic combination of four limit switches S11, S12, S21, and S22 controls the four sets of coils 1Y1, 1Y2, 2Y1, and 2Y2 of the two three-position four-way solenoid directional valves, thereby realizing the sequential control of hydraulic cylinder 1A working advance and stop, hydraulic cylinder 2A working advance and stop, hydraulic cylinder 2A rapid retraction and stop, and hydraulic cylinder 1A rapid retraction and stop.

5. The workpiece indexing electro-hydraulic control system according to claim 1, characterized in that: One-way throttle valves are installed between the three-position four-way solenoid directional valves and the hydraulic cylinders on the two hydraulic branches. The oil inlet flow rate is adjusted through the valves, thereby controlling the speed of hydraulic cylinders 1A and 2A during their working stroke to meet the working rhythm of the production line. When the hydraulic cylinders return, the oil returns through the one-way valve of the one-way throttle valve. At this time, the throttling function is ineffective, thereby realizing the rapid return of the hydraulic cylinders.

6. The workpiece indexing electro-hydraulic control system according to claim 1, characterized in that: A relief valve is connected in parallel to the high-pressure oil outlet of the hydraulic pump to set the system working pressure and to ensure safe overflow in case of system overload, thus preventing damage to the hydraulic pump.

7. The workpiece indexing electro-hydraulic control system according to claim 1, characterized in that: A check valve is installed between the hydraulic pump and the three-position four-way solenoid directional valve to prevent high-pressure oil from flowing back into the hydraulic pump under overload impact conditions, which could cause hydraulic pump failure.

8. The workpiece indexing electro-hydraulic control system according to claim 1, characterized in that: A relief valve is connected in parallel to the high-pressure oil outlet of the hydraulic pump to set the system working pressure and to ensure safe overflow in case of system overload, thus preventing damage to the hydraulic pump.

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