A method and device for combined control of stage cylinder action and process pressure variation

Abstract

The application discloses a combined control method and device for phased action of an oil cylinder and change of process pressure, wherein two branch hydraulic lines are inserted into a main hydraulic line, one branch hydraulic line is a set of quantitative oil distribution device, phased control of full stroke action of a hydraulic executing element is realized, and meanwhile, through accurate control of oil injection amount of the hydraulic executing element, the action stroke of each phase of the executing element is accurately controlled; the other branch hydraulic line is a set of pressure control and direction control unit, after the pressure of the passage is controlled by the main hydraulic line, the pressure of the passage is controlled again through the branch hydraulic line, so that the action pressure of the executing element is changed and controlled.

Description

Technical Field

[0001] This invention relates to the fields of mechanics and hydraulics, specifically to a control method and apparatus for a hydraulic device. Background Technology

[0002] When manually mounting a workpiece on an internal grinding machine using a hydraulic chuck:

[0003] 1. To prevent the hydraulic chuck from clamping the operator's hand, the chuck needs to perform two phased actions to clamp the workpiece. The operator puts the workpiece into the chuck, and the first action of the chuck clamps the workpiece halfway to prevent it from falling. The operator then removes their hand, and the second action of the chuck completes the full clamping of the workpiece.

[0004] 2. During workpiece machining, sometimes the machined inner hole passes inspection on the equipment, but upon removal of the workpiece for inspection, the inner hole's precision is magnified, leading to product defects. This is because excessive hydraulic chuck pressure causes product deformation. Furthermore, during the initial roughing process, the workpiece experiences high stress, requiring high pressure to prevent movement. To reduce deformation, during finish machining, the workpiece experiences less stress, allowing for reduced pressure. Therefore, a pressure switching mechanism must be added to the hydraulic system to change the pressure of the actuator during continuous operation, thus achieving the function of decreasing chuck pressure. Existing equipment typically does not simultaneously achieve both of these functions. Summary of the Invention

[0005] To address the aforementioned problems, this invention discloses a combined control method for staged cylinder movement and process pressure changes. This method involves inserting two sub-hydraulic lines into the main hydraulic line. One sub-hydraulic line is a quantitative oil distribution device that enables staged control of the hydraulic actuator's full stroke. Simultaneously, by precisely controlling the oil injection quantity into the hydraulic actuator, the stroke of the actuator at each stage is precisely controlled. The other sub-hydraulic line is a pressure and direction control unit. After the main hydraulic line controls the pressure in this passage, the sub-hydraulic line again controls the pressure in this passage, thereby changing and controlling the actuator's operating pressure.

[0006] The operation of the hydraulic cylinder is divided into four stages:

[0007] (1). High-pressure extension action of the hydraulic cylinder: The hydraulic cylinder releases the workpiece;

[0008] (2). High-pressure recovery and clamping action of hydraulic cylinder: When the workpiece is manually installed, the hydraulic cylinder clamps half of it to prevent the workpiece from falling and to prevent the hand from being pinched;

[0009] (3). High-pressure secondary recovery and clamping action of hydraulic cylinder: For manually installed workpieces, the hydraulic cylinder fully clamps the workpieces, and the equipment begins rough grinding of the workpieces;

[0010] (4) Low-pressure recovery clamping action of hydraulic cylinder: release part of the clamping pressure of hydraulic cylinder to prevent workpiece deformation, and the equipment starts to fine grind the workpiece.

[0011] The high-pressure extension action of the hydraulic cylinder is as follows: Hydraulic oil entering from port P of the main valve plate will flow through the main stacked valve group, through port PA of the main solenoid directional valve, and from port A of the main valve plate to chamber a of the hydraulic cylinder. The hydraulic oil in chamber b of the hydraulic cylinder will enter the quantitative oil distribution device through port A1 of the valve plate and return to the oil tank in two ways: one way is that the hydraulic oil flows into chamber c of the valve body, pushes the piston rod to move towards chamber d, and forces the hydraulic oil in chamber d of the valve body out. The hydraulic oil will flow out through port P1 of the valve body. The other way is that the hydraulic oil flows through the internal pipe of the valve body, port A of the solenoid valve plate, ports A1-P1 of the auxiliary solenoid directional valve, port P of the solenoid valve plate, and port P1 of the valve body. The two return oils merge, then flow through port B of the diverter valve block and port B2 of the pressure diverter valve block, then through the check valve and flow back to the main stacked valve group from port B1 of the pressure diverter valve block, and then through port BT of the main solenoid directional valve and port T of the main valve plate to return to the oil tank.

[0012] The high-pressure recovery and clamping action of the hydraulic cylinder is as follows: Hydraulic oil entering from port P of the main valve plate flows through the main stacked valve group, through port PB of the main solenoid directional valve, and out through port B1 of the pressure diversion valve block. It then enters the diversion pressure control stacked valve group from port P of the pressure diversion valve block, passes through the pressure diversion valve block, the stacked B1-way pressure reducing valve, and port P1-A1 of the diversion pressure control valve, and flows out from port A of the pressure diversion valve block. It then flows back to the main stacked valve group from port B2 of the pressure diversion valve block through the check valve, and flows out from port B of the diversion valve block. Finally, it enters the quantitative oil distribution device through port P1 of the valve body. At this time, port P1-A1 of the auxiliary solenoid directional valve is disconnected, so the hydraulic oil can only flow into the d chamber of the valve body, pushing the piston rod to move towards the c chamber. The piston rod retracts, forcing the hydraulic oil out of the c chamber of the valve body. The quantitative hydraulic oil in the c chamber flows out through port A1 of the valve plate and enters the b chamber of the hydraulic cylinder. The hydraulic oil in chamber a is forced to retract a certain distance, and the hydraulic oil in chamber a will enter the main superimposed valve group and the main solenoid directional valve AT through port A of the main valve plate, and finally flow back to the oil tank from port T of the main valve plate. The retraction distance of the hydraulic cylinder rod is adjusted by the stroke adjustment screw. At this time, the pressure claw at the front end of the hydraulic cylinder does not clamp the workpiece, but it can prevent the workpiece 29 from falling. At the same time, the hydraulic oil flowing through the diverter valve block will also flow out from another port A on the side of the diverter valve block, enter from port T1 of the valve body, pass through port T1-B1 of the auxiliary solenoid directional valve, port B on the side of the solenoid valve plate, the one-way throttle valve and the pressure switch, and flow back to the oil tank. This process is controlled by the one-way throttle valve to control the size of the return flow, thereby controlling the speed of the hydraulic cylinder rod retraction action. The alarm pressure of the pressure switch is set, and when the hydraulic cylinder rod retraction speed is abnormal, an alarm signal is issued.

[0013] The high-pressure secondary recovery and clamping action of the hydraulic cylinder is as follows: After the high-pressure primary recovery and clamping action of the hydraulic cylinder, the main solenoid directional valve and the diversion pressure control valve do not operate. The hydraulic oil entering from the P port of the main valve plate will flow through the main stacked valve group, through the PB port of the main solenoid directional valve, and out through the B1 port of the pressure diversion valve block. It will then enter the diversion pressure control stacked valve group from the P port of the pressure diversion valve block, through the pressure diversion valve block, the stacked B1-way pressure reducing valve, and the P1-A1 ports of the diversion pressure control valve, and out through the A port of the pressure diversion valve block. It will then flow back to the main stacked valve group from the B2 port of the pressure diversion valve block through the check valve, and out through the B port of the diversion valve block. Finally, it will enter the quantitative oil distribution device through the P1 port of the valve body. During the primary recovery action of the hydraulic cylinder, the piston rod in the valve body has moved to the c-chamber side, and the piston... The piston rod continues to move towards chamber c. At this time, the hydraulic oil flows out through the P port of the solenoid valve plate, P1-A1 of the auxiliary solenoid directional valve, A port of the solenoid valve plate, and A1 port of the valve body and valve plate into chamber b of the cylinder. This forces the cylinder rod to move a second time, causing all the hydraulic oil in chamber a to be forced out. The hydraulic oil then enters the main superimposed valve group and the AT port of the main solenoid directional valve through the A port of the main valve plate, and finally flows back to the oil tank from the T port of the main valve plate. The cylinder rod retracts to its maximum extent, and the pressure claw at the front end of the cylinder presses the workpiece under high pressure. At the same time, since the T1-B1 of the auxiliary solenoid directional valve has been disconnected, the returning hydraulic oil will no longer control the speed of the cylinder rod's second retraction action through the one-way throttle valve. Instead, the pressure in the oil circuit itself controls the speed of the cylinder rod's second retraction action.

[0014] The low-pressure recovery clamping action of the hydraulic cylinder is as follows: After the high-pressure secondary recovery clamping action of the hydraulic cylinder, the main solenoid directional valve and the auxiliary solenoid directional valve do not operate. The hydraulic oil entering from the P port of the main valve plate will flow through the main stacked valve group, through the PB port of the main solenoid directional valve, and out through the B1 port of the pressure diverting valve block. It will then enter the diverting pressure control stacked valve group from the P port of the pressure diverting valve block, through the pressure diverting valve block, the stacked B1-way pressure reducing valve, and the P1-B1 of the diverting pressure control valve, and out through the B port of the pressure diverting valve block. It will then flow back to the main stacked valve group from the B2 port of the pressure diverting valve block through the check valve, and out through the B port of the diverting valve block. Finally, it will enter the quantitative oil distribution device through the P1 port of the valve body. During the secondary recovery action of the hydraulic cylinder, the hydraulic oil has flowed out through the P port of the solenoid valve plate, the P1-A1 of the auxiliary solenoid directional valve, the A port of the solenoid valve plate, and the A1 port of the valve body and valve plate into the b chamber of the hydraulic cylinder, and completed the return of the hydraulic oil in the a chamber of the hydraulic cylinder to the oil tank 1. During this process, the hydraulic oil flows through the P1-B1 of the diversion pressure control valve and the B channel of the stacked B1-way pressure reducing valve. The stacked B1-way pressure reducing valve controls the pressure of the hydraulic oil in the B channel. The hydraulic oil flowing into the hydraulic cylinder is controlled by the stacked B1-way pressure reducing valve in the diversion pressure control stacked valve group. The pressure decreases, releasing part of the clamping pressure of the hydraulic cylinder, and the pressure claw at the front end of the hydraulic cylinder presses the workpiece with low pressure.

[0015] The present invention further discloses an apparatus for implementing the combined control method of staged cylinder action and process pressure change as described in the claims, including an oil tank, a main superimposed valve group, a quantitative oil distribution device, and a diversion pressure control superimposed valve group;

[0016] The oil tank is equipped with a hydraulic pump, filter 2 is installed at the oil inlet of the hydraulic pump, and a pressure gauge and a check valve are installed at the oil outlet of the hydraulic pump.

[0017] The structure of the main stacked valve group is as follows: the main valve plate, the flow divider block, the pressure flow divider block, the stacked check valve, the stacked A-way pressure reducing valve, the stacked B-way pressure reducing valve, and the main solenoid directional valve are stacked and connected by screws; O-rings are installed at the corresponding hole positions on the mating surfaces of each component of the main valve plate, the flow divider block, the pressure flow divider block, the stacked check valve, the stacked A-way pressure reducing valve, the stacked B-way pressure reducing valve, and the main solenoid directional valve.

[0018] The structure of the quantitative oil distribution device is as follows: the valve plate, valve body, solenoid valve plate, and auxiliary solenoid directional valve are connected together by screws, and the components are sealed with O-rings. The piston rod, end cap, and stroke adjustment screw are installed in the valve body and sealed with O-rings. A pipeline is led out from the side of the solenoid valve plate and connected to a one-way throttle valve and a pressure switch. The return oil pipe of the one-way throttle valve is connected to the oil tank.

[0019] The structure of the diversion pressure control stacked valve group is as follows: the main valve plate, the pressure dividing valve block, the stacked B-way pressure reducing valve, and the diversion pressure control valve are stacked and connected by screws. O-rings are installed at the corresponding hole positions on the mating surfaces of the main valve plate, the pressure dividing valve block, the stacked B1-way pressure reducing valve, and the diversion pressure control valve.

[0020] Ports B1 and B2 of the pressure diverter valve block are connected to ports P, A, and B of the pressure divider valve block. A check valve installed between ports B1 and B2 on the side of the pressure diverter valve block allows liquid to flow from port B2 to port B1 only; a check valve installed between port A and port B2 on the side of the pressure divider valve block allows liquid to flow from port A to port B2 only; a check valve installed between port B and port B2 on the side of the pressure divider valve block allows liquid to flow from port B to port B2 only.

[0021] The oil inlet P of the main valve plate is connected to the check valve at the outlet of the hydraulic pump;

[0022] The return port T of the main valve plate is connected to the oil tank.

[0023] The A port on the side of the diversion valve block is connected to the T1 port of the valve body in the quantitative oil distribution device.

[0024] The B port on the side of the diversion valve block is connected to the P1 port of the valve body in the quantitative oil distribution device.

[0025] Port A at the bottom of the main valve plate is connected to the right chamber a of the oil cylinder;

[0026] Block port B on the main valve plate, and connect port A1 of the valve plate in the quantitative oil distribution device to the left chamber b of the oil cylinder.

[0027] The end cap has a through hole at its center. The through hole is smooth near the valve body and has a sealing concave ring. A sealing ring is installed inside the concave ring. The end of the through hole away from the valve body is threaded. The front part of the adjusting screw is smooth, and the rear part of the adjusting screw is threaded. The adjusting screw is threadedly connected to the end cap.

[0028] A wear-resistant sleeve is provided between the inner cavity of the valve body and the piston rod.

[0029] The advantages of this invention are: In a hydraulic system, by inserting two branch hydraulic lines into the main hydraulic line, one branch hydraulic line is a set of quantitative oil distribution device, which mainly realizes the staged control of the full stroke of the hydraulic actuator, and at the same time, by precisely controlling the oil injection of the hydraulic actuator, the stroke of the actuator at each stage is precisely controlled; the other branch hydraulic line is a set of pressure control and direction control unit, which can control the pressure of this passage again through the branch hydraulic line after the pressure of this passage is controlled by the main hydraulic line, thereby realizing the change and control of the action pressure of the actuator. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall connection of the hydraulic system of the present invention (the high-pressure extension action of the oil cylinder);

[0031] Figure 2 A schematic diagram of the high-pressure recovery and clamping action of the hydraulic cylinder;

[0032] Figure 3 Schematic diagram of the high-pressure secondary recovery clamping action and the low-pressure recovery clamping action of the hydraulic cylinder; Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In hydraulic valve blocks, the common connection markings PTAB represent different hydraulic circuit functions. P port is the system inlet, responsible for receiving high-pressure hydraulic fluid. T port is the system return port, used to return used fluid to the tank, maintaining stable system pressure. A port refers to the actuator inlet, which delivers high-pressure fluid to the actuator, providing sufficient power to complete the intended action. B port is the actuator outlet; after the actuator completes its action, excess fluid flows back to the system return port through this port. In this embodiment, PTAB may vary in different control valve blocks, becoming ptab or p1t1a1b1, all representing the same meaning.

[0035] As shown in the figure, the installation method of this invention is as follows:

[0036] 1. Install the oil tank: An oil tank 1 is provided. The filter 2 is installed at the oil inlet of the hydraulic pump 3 and fixed on the oil tank 1 along with the hydraulic pump 3. The pressure gauge 4 and the check valve 5 are installed at the oil outlet of the hydraulic pump 3.

[0037] II. Installation of the main stacked valve assembly 30: A main valve plate 7 is provided. The main valve plate 7, the diversion valve block 8, the pressure diversion valve block 8a, the stacked check valve 9, the stacked A-way pressure reducing valve 10, the stacked B-way pressure reducing valve 11, and the main solenoid directional valve 12 are stacked and connected by screws. O-rings are installed at the corresponding hole positions on the mating surfaces of the main valve plate 7, the diversion valve block 8, the pressure diversion valve block 8a, the stacked check valve 9, the stacked A-way pressure reducing valve 10, the stacked B-way pressure reducing valve 11, and the main solenoid directional valve 12. Pressure gauge 1 26 and pressure gauge 2 27 are installed.

[0038] III. Installation of the quantitative oil distribution device 32: Connect the valve plate 16, valve body 15, solenoid valve plate 24, and auxiliary solenoid directional valve 13 together with screws, and seal the connections between each component with O-rings. Install the piston rod 17, end cap 18, and stroke adjusting screw 19 into the valve body 15 and seal them with O-rings. Lead out a pipeline from the side of the solenoid valve plate 24, connect the one-way throttle valve 20 and pressure switch 21, and connect the return oil pipe to the oil tank 1.

[0039] IV. Install the diversion pressure control stacked valve group 31: Then stack the main valve plate 7, pressure dividing valve block 44, stacked B-way pressure reducing valve 45, and diversion pressure control valve 14 and connect them with screws. Install O-rings at the corresponding hole positions on the mating surfaces of the main valve plate 7, pressure dividing valve block 44, stacked B1-way pressure reducing valve 45, and diversion pressure control valve 14, and install the pressure gauge 46.

[0040] V. Connecting the valve assembly: Use hydraulic pipes, connectors, check valves 41, 42, and 43 to connect the pressure control stacked valve assembly 31. Connect ports B1 and B2 of the pressure diversion valve block 8a to ports P, A, and B of the pressure dividing valve block 44. Ensure that check valve 1 41 installed between ports B1 and B2 on the side of the pressure diversion valve block 8a only allows liquid to flow from port B2 to port B1; check valve 3 43 installed between port A on the side of the pressure dividing valve block 44 and port B2 on the side of the pressure diversion valve block 8a only allows liquid to flow from port A to port B2; and check valve 2 42 installed between port B on the side of the pressure dividing valve block 44 and port B2 on the side of the pressure diversion valve block 8a only allows liquid to flow from port B to port B2.

[0041] VI. Connecting the components:

[0042] 1) Connect the oil inlet P of the main valve plate 7 and the check valve 5 at the outlet of the hydraulic pump 3 using the oil outlet pipe 6;

[0043] 2) Connect the return port T of the main valve plate 7 and the oil tank 1 with the return oil pipe 23.

[0044] 3) Connect port A on the side of the diversion valve block 8 to port T1 of the valve body 15 in the quantitative oil distribution device 32 using a hydraulic pipe;

[0045] 4) Connect port B on the side of the diversion valve block 8 to port P1 of the valve body 15 in the quantitative oil distribution device 32 using a hydraulic pipe.

[0046] 5) Connect port A at the bottom of the main valve plate 7 to the right chamber a of the cylinder 22 using a hydraulic pipe;

[0047] 6) Block the B port on the main valve plate 7 with the plug 25, and connect the A1 port of the valve plate 16 in the quantitative oil distribution device 32 and the left chamber b of the oil cylinder 22 with a hydraulic pipe.

[0048] Port C is an outlet of the solenoid valve plate 24. Port C is connected to the B circuit of the auxiliary solenoid directional valve 13. A pressure switch 21 and a one-way throttle valve 20 are connected to the side of port C of the solenoid valve plate 24. The one-way throttle valve 20 overflows back to the oil tank 1. The overflow can regulate the oil circuit pressure. The alarm pressure of the pressure switch is set. When the cylinder rod retraction speed is abnormal or the pressure changes, an alarm signal is issued.

[0049] The working principle of this invention is:

[0050] The operation of hydraulic cylinder 22 is divided into four stages:

[0051] 1. High-pressure extension action of hydraulic cylinder 22: Hydraulic cylinder 22 releases workpiece 29

[0052] 2. High-pressure single-stage clamping action of hydraulic cylinder 22: When the workpiece 29 is manually installed, hydraulic cylinder 22 clamps it halfway to prevent the workpiece 29 from falling and to prevent the hand from being pinched.

[0053] 3. High-pressure secondary recovery and clamping action of hydraulic cylinder 22: For manually installed workpiece 29, hydraulic cylinder 22 fully clamps workpiece 29, and the equipment begins rough grinding of workpiece 29.

[0054] 4. Low-pressure recovery clamping action of hydraulic cylinder 22: Release part of the clamping pressure of hydraulic cylinder 22 to prevent workpiece 29 from deforming, and the equipment begins precision grinding of workpiece 29.

[0055] Description of the action process:

[0056] 1. The high-pressure extension action of hydraulic cylinder 22, such as Figure 1 As shown, the main solenoid directional valve 12 and the auxiliary solenoid directional valve 13 are in Figure 1 At the indicated position, hydraulic oil entering from port P of the main valve plate 7 will flow through the main superimposed valve group 30, through port PA of the main solenoid directional valve 12, and from port A of the main valve plate 7 to chamber a of the cylinder 22. Hydraulic oil in chamber b of the cylinder will enter the quantitative oil distribution device 32 through port A1 of the valve plate 16, and return to the oil tank 1 in two paths: one path is hydraulic oil flowing into chamber c of the valve body 15, pushing the piston rod 17 to move towards chamber d (piston rod 17 extends), forcing out the hydraulic oil in chamber d of the valve body 15. The hydraulic oil will then flow through the valve body 15... The oil flows out from port P1 (another path is for hydraulic oil to flow out through the internal pipe of valve body 15, port A of solenoid valve plate 24, A1-P1 of auxiliary solenoid directional valve 13, port P of solenoid valve plate 24, and port P1 of valve body 15). The two return oil paths merge, then flow out through port B of diverter valve block 8 and port B2 of pressure diverter valve block 8a, then flow back to main superimposed valve group 30 through check valve 41 from port B1 of pressure diverter valve block 8a, and then flow back to oil tank 1 through port BT of main solenoid directional valve 12 and port T of main valve plate 7.

[0057] 2. The hydraulic cylinder 22 performs a high-pressure, single-stage retraction and clamping action, such as... Figure 2 As shown, the main solenoid directional valve 12, the auxiliary solenoid directional valve 13, and the flow divider pressure control valve 14 all operate simultaneously. Figure 2At the indicated position, hydraulic oil entering from port P of the main valve plate 7 flows through the main stacked valve group 30, through port PB of the main solenoid directional valve 12, through port B1 of the pressure diversion valve block 8a, and through port P of the pressure dividing valve block 44 into the diversion pressure control stacked valve group 31. It then flows through port P1-A1 of the pressure dividing valve block 44, the stacked B1-way pressure reducing valve 45, and the diversion pressure control valve 14, exiting through port A of the pressure dividing valve block 44. It then flows back to the main stacked valve group 30 through port B2 of the pressure diversion valve block 8a via the check valve 43, exiting through port B of the diversion valve block 8a, and entering the quantitative oil distribution device 32 through port P1 of the valve body 15. At this time, the auxiliary solenoid directional valve 13's port P1-A1... Since 1 is disconnected, the hydraulic oil can only flow into the d chamber of the valve body 15 to push the piston rod 17 to move towards the c chamber (piston rod 17 retracts), thus forcing the hydraulic oil out of the c chamber of the valve body 15. A fixed amount of hydraulic oil in the c chamber flows out through the A1 port of the valve plate 16 and into the b chamber of the cylinder 22, forcing the cylinder rod to retract a certain distance. The hydraulic oil in the a chamber will enter the main superimposed valve group 30 and the AT port of the main solenoid directional valve 12 through the A port of the main valve plate 7, and finally flow back to the oil tank 1 from the T port of the main valve plate 7. The retraction distance of the cylinder rod can be adjusted by the stroke adjustment screw 19. At this time, the pressure claw 28 at the front end of the cylinder 22 does not clamp the workpiece 29, but it can prevent the workpiece 29 from falling.

[0058] Meanwhile, the hydraulic oil flowing through the diverter valve block 8 will also flow out from another port A on the side of the diverter valve block 8, enter from port T1 of the valve body 15, pass through port T1-B1 of the auxiliary solenoid directional valve 13, port B on the side of the solenoid valve plate 24, the one-way throttle valve 20, and the pressure switch 21, and flow back to the oil tank 1. This process controls the amount of return flow through the one-way throttle valve 20, thereby controlling the speed of one retraction action of the cylinder rod. The alarm pressure of the pressure switch 21 is set, and when the retraction speed of the cylinder rod is abnormal, an alarm signal is issued.

[0059] 3. The high-pressure secondary recovery and clamping action of hydraulic cylinder 22, such as... Figure 3 As shown, after the high-pressure recovery and clamping action of the hydraulic cylinder 22, the main solenoid directional valve 12 and the flow divider pressure control valve 14 do not operate, while the auxiliary solenoid directional valve 13 operates. Figure 3As shown, hydraulic oil entering from port P of the main valve plate 7 flows through the main stacked valve group 30, through port PB of the main solenoid directional valve 12, through port B1 of the pressure diversion valve block 8a, and through port P of the pressure diversion valve block 44 into the diversion pressure control stacked valve group 31. It then flows through the pressure diversion valve block 44, the stacked B1-way pressure reducing valve 45, and ports P1-A1 of the diversion pressure control valve 14, exiting through port A of the pressure diversion valve block 44. It then flows back to the main stacked valve group 30 through port B2 of the pressure diversion valve block 8a via the check valve 43, exiting through port B of the diversion valve block 8a, and finally entering the quantitative oil distribution device 32 through port P1 of the valve body 15. During the first recovery action of the cylinder 22... During the process, the piston rod 17 in the valve body 15 has moved to the c-cavity side, and the piston rod 17 can no longer move to the c-cavity side. At this time, the hydraulic oil flows out through the P port of the solenoid valve plate 24, the P1-A1 of the auxiliary solenoid directional valve 13, the A port of the solenoid valve plate 24, the A1 port of the valve body 15 and the valve plate 16 and enters the b-cavity of the cylinder 22, forcing the cylinder rod to move a second time, so that all the hydraulic oil in the a-cavity is squeezed out. The hydraulic oil enters the main superimposed valve group 30 and the AT port of the main solenoid directional valve 12 through the A port of the main valve plate 7, and finally flows back to the oil tank 1 from the T port of the main valve plate 7. The cylinder rod is retracted to the maximum extent, and the pressure claw 28 at the front end of the cylinder 22 presses the workpiece 29 under high pressure.

[0060] At the same time, T1-B1 of the auxiliary solenoid directional valve 13 has been disconnected, and the returning hydraulic oil will no longer control the speed of the secondary retraction action of the cylinder rod through the one-way throttle valve 20. Instead, the pressure in the oil circuit itself will be used to control the speed of the secondary retraction action of the cylinder rod.

[0061] 4. The low-pressure recovery and clamping action of hydraulic cylinder 22, such as... Figure 3 As shown, after the high-pressure secondary recovery and clamping action of the hydraulic cylinder 22, the main solenoid directional valve 12 and the auxiliary solenoid directional valve 13 do not operate, and the flow divider pressure control valve 14 operates. Figure 3 At the position of the pressure control valve 14a shown, hydraulic oil entering from port P of the main valve plate 7 flows through the main stacked valve group 30, through port PB of the main solenoid directional valve 12, through port B1 of the pressure diversion valve block 8a, and enters the pressure control stacked valve group 31 from port P of the pressure dividing valve block 44. It then flows through the pressure dividing valve block 44, the stacked B1-way pressure reducing valve 45, and ports P1-B1 of the pressure control valve 14a, exiting from port B of the pressure dividing valve block 44, and finally through the check valve 42 from the pressure diversion valve 8a. The hydraulic oil flows back to the main superimposed valve group 30 from port B2 of block 8a, flows out from port B of the diversion valve block 8, and enters the quantitative oil distribution device 32 through port P1 of valve body 15. During the secondary recovery action of cylinder 22, the hydraulic oil has flowed out through port P of solenoid valve plate 24, port P1-A1 of auxiliary solenoid directional valve 13, port A of solenoid valve plate 24, and port A1 of valve body 15 and valve plate 16 into chamber b of cylinder 22, and completes the return of hydraulic oil from chamber a of cylinder 22 to oil tank 1.

[0062] During this process, hydraulic oil flows through P1-B1 of the diversion pressure control valve 14a and through B of the superimposed B1-path pressure reducing valve 45. The superimposed B1-path pressure reducing valve 45 controls the pressure of the hydraulic oil in B. Therefore, the hydraulic oil flowing into the cylinder 22 is controlled by the superimposed B1-path pressure reducing valve 45 in the diversion pressure control superimposed valve group 31. The pressure decreases, releasing part of the clamping pressure of the cylinder 22. The pressure claw 28 at the front end of the cylinder 22 presses the workpiece 29 with low pressure.

Claims

1. A method for joint control of staged cylinder movement and process pressure changes, characterized in that: By inserting two sub-hydraulic lines into the main hydraulic line, one sub-hydraulic line is a set of quantitative oil distribution devices to achieve staged control of the full stroke of the hydraulic actuator. At the same time, by precisely controlling the oil injection amount of the hydraulic actuator, the stroke of the actuator at each stage is precisely controlled. The other sub-hydraulic line is a set of pressure control and direction control units. After the pressure of this passage is controlled by the main hydraulic line, the pressure of this passage is controlled again through the sub-hydraulic line, thereby realizing the change and control of the actuator's operating pressure.

2. The combined control method for staged cylinder movement and process pressure changes according to claim 1, characterized in that: The operation of the hydraulic cylinder is divided into four stages: (1). High-pressure extension action of the hydraulic cylinder: The hydraulic cylinder releases the workpiece; (2). High-pressure recovery and clamping action of hydraulic cylinder: When the workpiece is manually installed, the hydraulic cylinder clamps half of it to prevent the workpiece from falling and to prevent the hand from being pinched; (3). High-pressure secondary recovery and clamping action of hydraulic cylinder: For manually installed workpieces, the hydraulic cylinder fully clamps the workpieces, and the equipment begins rough grinding of the workpieces; (4) Low-pressure recovery clamping action of hydraulic cylinder: release part of the clamping pressure of hydraulic cylinder to prevent workpiece deformation, and the equipment starts to fine grind the workpiece.

3. The combined control method for staged cylinder movement and process pressure changes according to claim 2, characterized in that... The high-pressure extension action of the hydraulic cylinder is as follows: Hydraulic oil entering from port P of the main valve plate will flow through the main stacked valve group, through port PA of the main solenoid directional valve, and from port A of the main valve plate to chamber a of the hydraulic cylinder. The hydraulic oil in chamber b of the hydraulic cylinder will enter the quantitative oil distribution device through port A1 of the valve plate and return to the oil tank in two ways: one way is that the hydraulic oil flows into chamber c of the valve body, pushes the piston rod to move towards chamber d, and forces the hydraulic oil in chamber d of the valve body out. The hydraulic oil will flow out through port P1 of the valve body. The other way is that the hydraulic oil flows through the internal pipe of the valve body, port A of the solenoid valve plate, ports A1-P1 of the auxiliary solenoid directional valve, port P of the solenoid valve plate, and port P1 of the valve body. The two return oils merge, then flow through port B of the diverter valve block and port B2 of the pressure diverter valve block, then through the check valve and flow back to the main stacked valve group from port B1 of the pressure diverter valve block, and then through port BT of the main solenoid directional valve and port T of the main valve plate to return to the oil tank.

4. The combined control method for staged cylinder movement and process pressure changes according to claim 2, characterized in that... The high-pressure recovery and clamping action of the hydraulic cylinder is as follows: Hydraulic oil entering from port P of the main valve plate flows through the main stacked valve group, through port PB of the main solenoid directional valve, and out through port B1 of the pressure diversion valve block. It then enters the diversion pressure control stacked valve group from port P of the pressure diversion valve block, passes through the pressure diversion valve block, the stacked B1-way pressure reducing valve, and port P1-A1 of the diversion pressure control valve, and flows out from port A of the pressure diversion valve block. It then flows back to the main stacked valve group from port B2 of the pressure diversion valve block through the check valve, and flows out from port B of the diversion valve block. Finally, it enters the quantitative oil distribution device through port P1 of the valve body. At this time, port P1-A1 of the auxiliary solenoid directional valve is disconnected, so the hydraulic oil can only flow into the d chamber of the valve body, pushing the piston rod to move towards the c chamber. The piston rod retracts, forcing the hydraulic oil out of the c chamber of the valve body. The quantitative hydraulic oil in the c chamber flows out through port A1 of the valve plate and enters the b chamber of the hydraulic cylinder. The hydraulic oil in chamber a is forced to retract a certain distance, and the hydraulic oil in chamber a will enter the main superimposed valve group and the main solenoid directional valve AT through port A of the main valve plate, and finally flow back to the oil tank from port T of the main valve plate. The retraction distance of the hydraulic cylinder rod is adjusted by the stroke adjustment screw. At this time, the pressure claw at the front end of the hydraulic cylinder does not clamp the workpiece, but it can prevent the workpiece 29 from falling. At the same time, the hydraulic oil flowing through the diverter valve block will also flow out from another port A on the side of the diverter valve block, enter from port T1 of the valve body, pass through port T1-B1 of the auxiliary solenoid directional valve, port B on the side of the solenoid valve plate, the one-way throttle valve and the pressure switch, and flow back to the oil tank. This process is controlled by the one-way throttle valve to control the size of the return flow, thereby controlling the speed of the hydraulic cylinder rod retraction action. The alarm pressure of the pressure switch is set, and when the hydraulic cylinder rod retraction speed is abnormal, an alarm signal is issued.

5. The combined control method for staged cylinder movement and process pressure changes according to claim 2, characterized in that... The high-pressure secondary recovery and clamping action of the hydraulic cylinder is as follows: After the high-pressure primary recovery and clamping action of the hydraulic cylinder, the main solenoid directional valve and the diversion pressure control valve do not operate. The hydraulic oil entering from the P port of the main valve plate will flow through the main stacked valve group, through the PB port of the main solenoid directional valve, and out through the B1 port of the pressure diversion valve block. It will then enter the diversion pressure control stacked valve group from the P port of the pressure diversion valve block, through the pressure diversion valve block, the stacked B1-way pressure reducing valve, and the P1-A1 ports of the diversion pressure control valve, and out through the A port of the pressure diversion valve block. It will then flow back to the main stacked valve group from the B2 port of the pressure diversion valve block through the check valve, and out through the B port of the diversion valve block. Finally, it will enter the quantitative oil distribution device through the P1 port of the valve body. During the primary recovery action of the hydraulic cylinder, the piston rod in the valve body has moved to the c-chamber side, and the piston... The piston rod continues to move towards chamber c. At this time, the hydraulic oil flows out through the P port of the solenoid valve plate, P1-A1 of the auxiliary solenoid directional valve, A port of the solenoid valve plate, and A1 port of the valve body and valve plate into chamber b of the cylinder. This forces the cylinder rod to move a second time, causing all the hydraulic oil in chamber a to be forced out. The hydraulic oil then enters the main superimposed valve group and the AT port of the main solenoid directional valve through the A port of the main valve plate, and finally flows back to the oil tank from the T port of the main valve plate. The cylinder rod retracts to its maximum extent, and the pressure claw at the front end of the cylinder presses the workpiece under high pressure. At the same time, since the T1-B1 of the auxiliary solenoid directional valve has been disconnected, the returning hydraulic oil will no longer control the speed of the cylinder rod's second retraction action through the one-way throttle valve. Instead, the pressure in the oil circuit itself controls the speed of the cylinder rod's second retraction action.

6. The combined control method for staged cylinder movement and process pressure changes according to claim 2, characterized in that... The low-pressure recovery clamping action of the hydraulic cylinder is as follows: After the high-pressure secondary recovery clamping action of the hydraulic cylinder, the main solenoid directional valve and the auxiliary solenoid directional valve do not operate. The hydraulic oil entering from the P port of the main valve plate will flow through the main stacked valve group, through the PB port of the main solenoid directional valve, and out through the B1 port of the pressure diverting valve block. It will then enter the diverting pressure control stacked valve group from the P port of the pressure dividing valve block, through the pressure dividing valve block, the stacked B1-way pressure reducing valve, and the P1-B1 of the diverting pressure control valve, and out through the pressure dividing valve block. The oil flows out from port B, then flows back to the main superimposed valve group from port B2 of the pressure diversion valve block through the check valve. It flows out from port B of the diversion valve block and enters the quantitative oil distribution device through port P1 of the valve body. During the secondary recovery action of the oil cylinder, the hydraulic oil has flowed out through port P of the solenoid valve plate, port P1-A1 of the auxiliary solenoid directional valve, port A of the solenoid valve plate, and port A1 of the valve body and valve plate into the b chamber of the oil cylinder, and completes the return of the hydraulic oil in the a chamber of the oil cylinder to the oil tank 1. During this process, hydraulic oil flows through the P1-B1 of the diversion pressure control valve and the B path of the superimposed B1-path pressure reducing valve. The superimposed B1-path pressure reducing valve controls the pressure of the hydraulic oil in the B path. The hydraulic oil flowing into the cylinder is controlled by the superimposed B1-path pressure reducing valve in the diversion pressure control superimposed valve group. The pressure decreases, releasing part of the clamping pressure of the cylinder, and the pressure claw at the front end of the cylinder presses the workpiece with low pressure.

7. An apparatus for implementing the combined control method of staged cylinder action and process pressure change as described in the claims, characterized in that: Includes oil tank, main stacked valve assembly, quantitative oil distribution device, and flow-dividing pressure control stacked valve assembly; The oil tank is equipped with a hydraulic pump, a filter is installed at the oil inlet of the hydraulic pump, and a pressure gauge and a check valve are installed at the oil outlet of the hydraulic pump. The structure of the main stacked valve group is as follows: the main valve plate, the flow divider block, the pressure flow divider block, the stacked check valve, the stacked A-way pressure reducing valve, the stacked B-way pressure reducing valve, and the main solenoid directional valve are stacked and connected by screws; O-rings are installed at the corresponding hole positions on the mating surfaces of each component of the main valve plate, the flow divider block, the pressure flow divider block, the stacked check valve, the stacked A-way pressure reducing valve, the stacked B-way pressure reducing valve, and the main solenoid directional valve. The structure of the quantitative oil distribution device is as follows: the valve plate, valve body, solenoid valve plate, and auxiliary solenoid directional valve are connected together by screws, and the components are sealed with O-rings. The piston rod, end cap, and stroke adjustment screw are installed in the valve body and sealed with O-rings. A pipeline is led out from the side of the solenoid valve plate and connected to a one-way throttle valve and a pressure switch. The return oil pipe of the one-way throttle valve is connected to the oil tank. The structure of the diversion pressure control stacked valve group is as follows: the main valve plate, the pressure dividing valve block, the stacked B-way pressure reducing valve, and the diversion pressure control valve are stacked and connected by screws. O-rings are installed at the corresponding hole positions on the mating surfaces of the main valve plate, the pressure dividing valve block, the stacked B1-way pressure reducing valve, and the diversion pressure control valve. Ports B1 and B2 of the pressure diverter valve block are connected to ports P, A, and B of the pressure divider valve block. A check valve installed between ports B1 and B2 on the side of the pressure diverter valve block allows liquid to flow from port B2 to port B1 only; a check valve installed between port A and port B2 on the side of the pressure divider valve block allows liquid to flow from port A to port B2 only; a check valve installed between port B and port B2 on the side of the pressure divider valve block allows liquid to flow from port B to port B2 only. The oil inlet P of the main valve plate is connected to the check valve at the outlet of the hydraulic pump; The return port T of the main valve plate is connected to the oil tank. The A port on the side of the diversion valve block is connected to the T1 port of the valve body in the quantitative oil distribution device. The B port on the side of the diversion valve block is connected to the P1 port of the valve body in the quantitative oil distribution device. Port A at the bottom of the main valve plate is connected to the right chamber a of the oil cylinder; Block port B on the main valve plate, and connect port A1 of the valve plate in the quantitative oil distribution device to the left chamber b of the oil cylinder.

8. The apparatus according to claim 7, characterized in that: The end cap has a through hole at its center. The through hole is smooth near the valve body and has a sealing concave ring. A sealing ring is installed inside the concave ring. The end of the through hole away from the valve body is threaded. The front part of the adjusting screw is smooth, and the rear part of the adjusting screw is threaded. The adjusting screw is threadedly connected to the end cap.

9. The apparatus according to claim 7, characterized in that: A wear-resistant sleeve is provided between the inner cavity of the valve body and the piston rod.

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