Hydraulic synchronous driving system and unloading platform

Abstract

The utility model discloses a hydraulic synchronous driving system and an unloading platform, and belongs to the technical field of hydraulic lifting. The hydraulic synchronous driving system comprises a driving adjusting loop, a driven adjusting loop, a first multi-stage oil cylinder, a second multi-stage oil cylinder, a liquid storage assembly and a control assembly, the first multi-stage oil cylinder (namely a master hydraulic cylinder) is controlled through a reversing valve, and the second multi-stage oil cylinder (namely a slave hydraulic cylinder) is controlled through a proportional reversing valve. The control assembly can detect the position of the first multi-stage oil cylinder and the position of the second multi-stage oil cylinder through the two rope type displacement sensors respectively and adjust control signals of the proportional reversing valve according to feedback signals of the two rope type displacement sensors, so that the second multi-stage oil cylinder moves along with the first multi-stage oil cylinder, and synchronous lifting is achieved. In this way, it can be ensured that the positions or speeds of the first multi-stage oil cylinder and the second multi-stage oil cylinder are kept consistent, and the synchronization precision of the hydraulic synchronous driving system can be improved.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic lifting technology, and in particular to a hydraulic synchronous drive system and an unloading platform. Background Technology

[0002] With the development of logistics technology, the logistics industry has increasingly higher requirements for efficiency and safety. Currently, most logistics transport vehicles do not include self-unloading devices. If manual labor is used in conjunction with forklifts and other auxiliary tools for unloading, especially for bulk goods, the unloading process is inefficient. Therefore, unloading platforms can be used to change the overall posture of logistics transport vehicles to unload the entire vehicle as a whole, thereby improving logistics efficiency.

[0003] The unloading platform typically uses a hydraulic synchronous drive system to control the lifting process of the platform. The hydraulic synchronous drive system can include two multi-stage cylinders and a distributor to lift the unloading platform by means of double-sided lifting, and the distributor controls the two multi-stage cylinders synchronously.

[0004] However, since the flow splitting accuracy of the flow splitter is greatly affected by the load, the flow splitting accuracy of the flow splitter will also be affected for multi-stage cylinders with long strokes, causing uneven loads on each cylinder and large synchronization errors, resulting in low stability of the hydraulic synchronous drive system. Utility Model Content

[0005] This utility model provides a hydraulic synchronous drive system and an unloading platform. It solves the problem of low stability in existing hydraulic synchronous drive systems. The technical solution is as follows:

[0006] According to one aspect of the present invention, a hydraulic synchronous drive system is provided, comprising: an active adjustment circuit, a driven adjustment circuit, a first multi-stage cylinder, a second multi-stage cylinder, a liquid storage component, and a control component;

[0007] The active adjustment circuit includes a first reversing valve and a first connecting oil circuit. The oil inlet and oil outlet of the first reversing valve are both connected to the liquid storage component. One working oil port of the first reversing valve is connected to the first multi-stage oil cylinder through the first connecting oil circuit.

[0008] The driven adjustment circuit includes a proportional directional valve and a second connecting oil circuit. The inlet and outlet of the proportional directional valve are both connected to the liquid storage component. One working port of the proportional directional valve is connected to the second multi-stage cylinder through the second connecting oil circuit.

[0009] Both the first multi-stage hydraulic cylinder and the second multi-stage hydraulic cylinder are equipped with a rope displacement sensor, which is used to detect the position of the piston rod in the first multi-stage hydraulic cylinder and the second multi-stage hydraulic cylinder;

[0010] The control component is electrically connected to the rope displacement sensor, the first directional valve, and the proportional directional valve, respectively.

[0011] Optionally, both the first multi-stage hydraulic cylinder and the second multi-stage hydraulic cylinder include: an outer cylinder barrel, a multi-stage piston, a first end cap, and the rope displacement sensor;

[0012] The multi-stage piston is located in the outer cylinder, and the multi-stage piston includes a piston rod and at least one piston cylinder nested outside the piston rod;

[0013] The first end cap is fixedly connected to one end of the outer cylinder. The first end cap has a receiving cavity, and the receiving cavity has a first opening on the side facing the outer cylinder.

[0014] The rope displacement sensor has a pull rope, at least a portion of which is located in the accommodating cavity, and one end of the pull rope is connected to the end of the piston rod through the first opening.

[0015] Optionally, the rope displacement sensor includes a drive motor, a rotating shaft, a drum, the pull rope, and an encoder, and the first end cap has a first mounting through hole, which communicates with the accommodating cavity;

[0016] The drive motor is located outside the first mounting through hole and is mounted on the first end cover.

[0017] The reel mechanism is installed in the accommodating cavity of the first end cap.

[0018] The rotating shaft passes through the first mounting through hole, and both ends of the rotating shaft are respectively connected to the drive motor and the drum;

[0019] At least a portion of the pull rope is wound around the drum;

[0020] The encoder is electrically connected to both the drive motor and the control component.

[0021] Optionally, the rope displacement sensor further includes a drum support and a pressure ring structure;

[0022] The roll support is fixedly installed on the inner wall of the accommodating cavity of the first end cover.

[0023] The drum is mounted on the drum support and is rotatably connected to the drum support. The surface of the drum has a plurality of annular guide grooves, which are arranged along the axial direction of the drum.

[0024] The pressure ring structure is located on one side of the drum and is fixedly connected to the drum support. The pressure ring structure is used to guide the pull rope into or out of the annular guide groove.

[0025] Optionally, the at least one piston cylinder includes a first piston cylinder, and both the first multi-stage cylinder and the second multi-stage cylinder further include: a first buffer pad and a second buffer pad;

[0026] The first buffer pad is located between the end of the piston rod near the first end cap and the bottom of the first piston cylinder, and the first buffer pad is fixedly connected to the end of the piston rod near the first end cap or the bottom of the first piston cylinder;

[0027] The second buffer pad is located between the end of the first piston cylinder near the first end cap and the bottom of the outer cylinder, and the second buffer pad is fixedly connected to the end of the first piston cylinder near the first end cap or the bottom of the outer cylinder.

[0028] Optionally, the active adjustment circuit further includes: a one-way inlet speed control valve, a one-way return throttle valve, and a first balance valve. The one-way inlet speed control valve and the one-way return throttle valve are connected in series in the first connecting oil circuit. Both working ports of the first balance valve are connected to the first connecting oil circuit, and the control port of the first balance valve is connected to the other working port of the first reversing valve.

[0029] The driven adjustment circuit further includes: a second balance valve, both working ports of the second balance valve are connected to the second connecting oil circuit, and the control port of the second balance valve is connected to the other working port of the proportional directional valve.

[0030] Optionally, the hydraulic synchronous drive system further includes a first throttle valve, a second throttle valve, and a ball valve, and the liquid storage assembly includes an oil reservoir, an oil outlet line, and an oil return line;

[0031] The first throttle valve is connected to the first end of the first multi-stage hydraulic cylinder and the first end of the ball valve, respectively;

[0032] The second throttle valve is connected to the first end of the second multi-stage hydraulic cylinder and the ball valve, respectively;

[0033] The second end of the ball valve is connected to the return oil pipeline;

[0034] Both the return oil line and the outlet oil line are connected to the oil storage tank.

[0035] Optionally, the hydraulic synchronous drive system further includes: a loading circuit, an auxiliary adjustment circuit, and an auxiliary cylinder;

[0036] The loading circuit includes a full unloading valve, a proportional relief valve, and a pressure limiting relief valve. The full unloading valve, the proportional relief valve, and the pressure limiting relief valve are all connected to the oil outlet line and the oil return line, respectively.

[0037] The auxiliary regulating circuit includes a second reversing valve and two one-way throttle valves. The oil inlet of the second reversing valve is connected to the oil outlet pipeline, and the oil outlet of the second reversing valve is connected to the oil return pipeline. The two working oil ports of the second reversing valve are respectively connected to the auxiliary oil cylinder through the two one-way throttle valves.

[0038] Optionally, the liquid storage assembly further includes an oil pump, a cooler, two filters, a temperature sensor, a dryer breather, and a heater;

[0039] The oil pump is installed on the oil outlet pipeline, the cooler is installed on the oil return pipeline, and the two filters are installed on the oil outlet pipeline and the oil return pipeline, respectively.

[0040] The temperature sensor, the drying breather, and the heater are all mounted on the oil tank. Furthermore, the oil tank has an internal isolation plate whose extension direction intersects with the hydraulic oil flow direction within the oil tank.

[0041] According to another aspect of the present invention, an unloading platform is provided, comprising: a bearing platform, a hydraulic synchronous drive system, a first rotating seat and a second rotating seat, wherein the hydraulic synchronous drive system includes the aforementioned hydraulic synchronous drive system;

[0042] One end of the bearing platform is connected to the first multi-stage cylinder and the second multi-stage cylinder in the hydraulic synchronous drive system. Both the first multi-stage cylinder and the second multi-stage cylinder are connected to the first rotating seat.

[0043] The second end of the bearing platform is connected to the second rotating seat.

[0044] The beneficial effects of the technical solution provided by this utility model embodiment include at least the following:

[0045] This utility model provides a hydraulic synchronous drive system comprising an active adjustment circuit, a driven adjustment circuit, a first multi-stage hydraulic cylinder, a second multi-stage hydraulic cylinder, a reservoir component, and a control component. The first multi-stage hydraulic cylinder (i.e., the master hydraulic cylinder) is controlled by a directional valve, and the second multi-stage hydraulic cylinder (i.e., the slave hydraulic cylinder) is controlled by a proportional directional valve. The control component can detect the positions of the first and second multi-stage hydraulic cylinders respectively using two rope displacement sensors, and adjust the control signal of the proportional directional valve based on the feedback signals from the two rope displacement sensors, so that the second multi-stage hydraulic cylinder follows the movement of the first multi-stage hydraulic cylinder, achieving synchronous lifting and lowering. This ensures that the positions or speeds of the first and second multi-stage hydraulic cylinders remain consistent, improving the synchronization accuracy of the hydraulic synchronous drive system and solving the problem of low stability in related technologies. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a schematic diagram of a hydraulic synchronous drive system provided in an embodiment of the present invention;

[0048] Figure 2 yes Figure 1 A schematic diagram of the loop section in the schematic diagram of the hydraulic synchronous drive system shown;

[0049] Figure 3 This is a schematic diagram of the structure of a first multi-stage hydraulic cylinder provided in an embodiment of the present invention;

[0050] Figure 4 yes Figure 3 The diagram shows a cross-sectional view of the first multi-stage hydraulic cylinder along the A1-A2 position.

[0051] Figure 5 This is a schematic diagram of the structure of a rope displacement sensor provided in an embodiment of this utility model;

[0052] Figure 6 yes Figure 5 A schematic diagram of a partial B1 structure of the rope displacement sensor shown.

[0053] Figure 7 yes Figure 1 The schematic diagram of the hydraulic synchronous drive system shown is a structural diagram of the liquid storage component.

[0054] Figure 8 This is a structural schematic diagram of an unloading platform provided in an embodiment of the present utility model. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0056] Although the present invention can be readily embodied in various forms, only some specific embodiments are shown in the accompanying drawings and will be described in detail in this specification. It is understood that this specification should be regarded as an exemplary illustration of the principles of the present invention and is not intended to limit the present invention to what is described herein.

[0057] Therefore, a feature pointed out in this specification is used to describe one feature of one embodiment of the present invention, and does not imply that every embodiment of the present invention must have the described feature. Furthermore, it should be noted that this specification describes many features. Although certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly stated. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.

[0058] In the embodiments shown in the accompanying drawings, the directional indications (such as up, down, left, right, front, and back) used to explain the structure and movement of the various elements of this invention are relative rather than absolute. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the descriptions of the positions of these elements change, these directional indications also change accordingly.

[0059] Please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 , Figure 1 This is a schematic diagram of a hydraulic synchronous drive system provided in an embodiment of the present invention. Figure 2 yes Figure 1 The schematic diagram shown is a schematic of the circuit part in the schematic diagram of the hydraulic synchronous drive system. Figure 3 This is a schematic diagram of the structure of a first multi-stage hydraulic cylinder 13 provided in an embodiment of the present invention. Figure 4 yes Figure 3 The schematic diagram of the cross-sectional structure of the first multi-stage cylinder 13 along the A1-A2 position shows that the hydraulic synchronous drive system may include: an active adjustment circuit 11, a driven adjustment circuit 12, a first multi-stage cylinder 13, a second multi-stage cylinder 14, a fluid storage assembly 15, and a control assembly (not shown in the figure). The active adjustment circuit 11 is used to adjust the extension and retraction state of the first multi-stage cylinder 13, the driven adjustment circuit 12 is used to adjust the extension and retraction state of the second multi-stage cylinder 14, and the fluid storage assembly 15 is used to store and provide hydraulic oil.

[0060] The active regulating circuit 11 may include a first directional valve 111 and a first connecting oil circuit 112. The inlet and outlet of the first directional valve 111 are both connected to the reservoir component 15. One working port of the first directional valve 111 is connected to the first multi-stage cylinder 13 via the first connecting oil circuit 112. The first directional valve 111 can control the extension and retraction of the first multi-stage cylinder 13 by changing the flow direction of the hydraulic oil. That is, by controlling the position of the valve core of the first directional valve 111, the movement state of the first multi-stage cylinder 13 (e.g., extension, retraction, or stop) can be controlled. For example, the first directional valve 111 may include a three-position four-way solenoid directional valve, and the first multi-stage cylinder 13 may include a piston hydraulic cylinder. The piston hydraulic cylinder is a single-acting hydraulic cylinder and may have one oil port, which can be used to connect to the first connecting oil circuit 112. The first multi-stage cylinder 13 can extend by being pushed by hydraulic oil to extend the multi-stage piston 133 and retract by external force (such as gravity or a spring).

[0061] The driven regulating circuit 12 may include a proportional directional valve 121 and a second connecting oil passage 122. The inlet and outlet of the proportional directional valve 121 are both connected to the reservoir assembly 15, and one working port of the proportional directional valve 121 is connected to the second multi-stage cylinder 14 via the second connecting oil passage 122. The proportional directional valve 121 can control the flow direction and flow rate of the hydraulic oil. For example, the proportional directional valve 121 may include a three-position four-way solenoid proportional directional valve 121, and the second multi-stage cylinder 14 may include a piston hydraulic cylinder.

[0062] Both the first multi-stage hydraulic cylinder 13 and the second multi-stage hydraulic cylinder 14 are equipped with a rope displacement sensor 131, which is used to detect the position of the piston rod 1331 in the first multi-stage hydraulic cylinder 13 and the second multi-stage hydraulic cylinder 14. The control component is electrically connected to the rope displacement sensor 131, the first directional valve 111, and the proportional directional valve 121, respectively.

[0063] In this embodiment of the invention, a master-slave control method is used to achieve synchronous control of the first multi-stage hydraulic cylinder 13 and the second multi-stage hydraulic cylinder 14. For example, the first multi-stage hydraulic cylinder 13 (i.e., the master hydraulic cylinder) is controlled by a directional valve, and the second multi-stage hydraulic cylinder 14 (i.e., the slave hydraulic cylinder) is controlled by a proportional directional valve 121. The control component can detect the positions of the first multi-stage hydraulic cylinder 13 and the second multi-stage hydraulic cylinder 14 through a rope displacement sensor 131, and adjust the control signal of the proportional directional valve 121 according to the feedback signal from the rope displacement sensor 131, so that the second multi-stage hydraulic cylinder 14 follows the movement of the first multi-stage hydraulic cylinder 13, achieving synchronous lifting and lowering. This ensures that the positions or speeds of the first multi-stage hydraulic cylinder 13 and the second multi-stage hydraulic cylinder 14 remain consistent, improving the synchronization accuracy of the hydraulic synchronous drive system.

[0064] Furthermore, by adopting a multi-stage cylinder structure, the size of the cylinder in the retracted state can be reduced, thereby making the space occupied by the hydraulic synchronous drive system smaller.

[0065] In summary, this utility model embodiment provides a hydraulic synchronous drive system including an active adjustment circuit 11, a driven adjustment circuit 12, a first multi-stage cylinder 13, a second multi-stage cylinder 14, a liquid storage component 15, and a control component. The first multi-stage cylinder 13 (i.e., the main hydraulic cylinder) is controlled by a directional valve, and the second multi-stage cylinder 14 (i.e., the slave hydraulic cylinder) is controlled by a proportional directional valve 121. The control component can detect the positions of the first multi-stage cylinder 13 and the second multi-stage cylinder 14 respectively through two rope displacement sensors 131, and adjust the control signal of the proportional directional valve 121 according to the feedback signals of the two rope displacement sensors 131, so that the second multi-stage cylinder 14 follows the movement of the first multi-stage cylinder 13 to achieve synchronous lifting and lowering. In this way, the position or speed of the first multi-stage cylinder 13 and the second multi-stage cylinder 14 can be kept consistent, which can improve the synchronization accuracy of the hydraulic synchronous drive system and solve the problem of low stability of hydraulic synchronous drive systems in related technologies.

[0066] Please refer to Figure 4 In one optional embodiment, both the first multi-stage cylinder 13 and the second multi-stage cylinder 14 include: an outer cylinder barrel 132, a multi-stage piston 133, a first end cap 134, and a rope-type displacement sensor 131. This is an embodiment of the present invention. Figure 4 Taking the first multi-stage hydraulic cylinder 13 as an example, the structure of the second multi-stage hydraulic cylinder 14 can be the same as that of the first multi-stage hydraulic cylinder 13.

[0067] A multi-stage piston 133 is located in an outer cylinder 132. The multi-stage piston 133 may include a piston rod 1331 and at least one piston cylinder (e.g., a first piston cylinder 1332) nested outside the piston rod 1331. A first end cap 134 is fixedly connected to one end of the outer cylinder 132. The first end cap 134 has a receiving cavity c1, and the receiving cavity c1 has a first opening k1 on the side facing the outer cylinder 132. A rope displacement sensor 131 has a pull rope 1311, at least a portion of which is located in the receiving cavity c1. One end of the pull rope 1311 is connected to the end of the piston rod 1331 through the first opening k1. One end of the pull rope 1311 can be fixedly connected to the end of the piston rod 1331 near the first end cap 134. When the first multi-stage hydraulic cylinder 13 is working, the piston rod 1331 can move along the length of the outer cylinder 132. When the piston rod 1331 moves, it can drive the pull rope 1311 to move, thereby obtaining the extension and retraction position of the first multi-stage hydraulic cylinder 13 through the rope displacement sensor 131. By setting the pull rope 1311 of the rope displacement sensor 131 inside the first end cap 134 and the outer cylinder 132 of the first multi-stage hydraulic cylinder 13, the interference of external foreign objects on the rope displacement sensor 131 can be reduced, thereby improving the accuracy of the rope displacement sensor 131.

[0068] Please refer to Figure 5 , Figure 5 This is a structural schematic diagram of a rope displacement sensor 131 provided in an embodiment of this utility model. Figure 5The diagram shows a rope displacement sensor 131 mounted on a first end cap 134. In one optional embodiment, the rope displacement sensor 131 includes a drive motor 1312, a rotating shaft 1313, a drum 1314, a pull rope 1311, and an encoder 1315. The first end cap 134 has a first mounting through hole k2, which communicates with a receiving cavity c1. The drive motor 1312 is located outside the first mounting through hole k2 and mounted on the first end cap 134. The drum 1314 is mounted within the receiving cavity c1 of the first end cap 134. The rotating shaft 1313 passes through the first mounting through hole k2, and both ends of the rotating shaft 1313 are connected to the drive motor 1312 and the drum 1314, respectively. At least a portion of the pull rope 1311 is wound around the drum 1314. The encoder 1315 is electrically connected to the drive motor 1312 and the control assembly, respectively. By winding the pull rope 1311 onto the drum 1314 and driving the drum 1314 to rotate via the drive motor 1312, the linear displacement of the piston rod 1331 can be converted into the rotational displacement of the drum 1314. The rotational displacement of the drum 1314 is then converted into an electrical signal via the encoder 1315. For example, when the pull rope 1311 is pulled or released, the drum 1314 rotates accordingly. The encoder 1315 can calculate the linear displacement of the pull rope 1311 by detecting the rotation angle or number of turns of the drum 1314, thereby obtaining the displacement of the piston rod 1331. The encoder 1315 can be electrically connected to a control component to transmit the detected position information to the control component.

[0069] like Figure 5 As shown, in an exemplary embodiment, the drive motor 1312 may include a servo motor, and the rope displacement sensor 131 may also include a flange support 1316, a thrust bearing 1317, a rotary seal 1318, a support ring 1319, and a drum bracket 131a; the flange support 1316 may be fixedly installed on the outside of the first mounting through hole k2 of the first end cover portion 134, and the flange support 1316 may be bolted to the first end cover portion 134.

[0070] The flange support 1316 may have a second mounting through hole k3, through which the output shaft of the drive motor 1312 can pass and be fixedly connected to the rotating shaft 1313. For example, the rotating shaft 1313 has opposing first and second ends. The first end can be connected to the drive motor 1312, and the second end can be fixedly connected to the drum 1314. The first end of the rotating shaft 1313 has a first groove c2, into which the output shaft of the drive motor 1312 can extend and be fixedly connected to the rotating shaft 1313. The output shaft of the drive motor 1312 can be threaded or snap-fitted into the rotating shaft 1313.

[0071] The flange support 1316 may have a second groove c3, the second mounting through hole k3 may be located at the bottom of the second groove c3, the first end of the rotating shaft 1313 may be located in the second groove c3, and the thrust bearing 1317 may be located between the first end of the rotating shaft 1313 and the bottom of the second groove c3 of the flange support 1316.

[0072] The rotary seal 1318 and the support ring 1319 can both be sleeved on the middle part of the rotating shaft 1313 and located between the rotating shaft 1313 and the hole wall of the first mounting through hole k2. The rotary seal 1318 and the support ring 1319 can both be embedded in the hole wall of the first mounting through hole k2.

[0073] The drum support 131a can be fixedly installed on the inner wall of the accommodating cavity c1 of the first end cover 134, and the drum 1314 can be installed on the drum support 131a and rotatably connected to the drum support 131a.

[0074] Please refer to Figure 6 , Figure 6 yes Figure 5 The schematic diagram of partial structure B1 of the rope displacement sensor 131 shown shows that, in an optional embodiment, the rope displacement sensor 131 may further include a pressure ring structure 131b. The surface of the drum 1314 has a plurality of annular guide grooves c4. The plurality of annular guide grooves c4 are arranged along the axial direction of the drum 1314. The pressure ring structure 131b is located on one side of the drum 1314 and is fixedly connected to the drum support 131a. The pressure ring structure 131b is used to guide the pull rope 1311 into or out of the annular guide grooves c4.

[0075] The drum support 131a may have a rope through hole, through which the pull rope 1311 can pass and be fixedly connected to the piston rod. The rope displacement sensor 131 may also include a bearing sleeve 131c, which may be located on the wall of the rope through hole and surround the pull rope 1311. The bearing sleeve 131c can reduce the coefficient of friction between the pull rope 1311 and the drum support 131a to avoid mutual wear between the pull rope 1311 and the drum support 131a during the movement.

[0076] Please refer to Figure 4 and Figure 5In an optional embodiment, at least one piston cylinder may include a first piston cylinder 1332, and the first multi-stage cylinder 13 and the second multi-stage cylinder 14 may each include: a first buffer pad 135 and a second buffer pad 136; the first buffer pad 135 is located between the end of the piston rod 1331 near the first end cap 134 and the bottom of the first piston cylinder 1332, and the first buffer pad 135 is fixedly connected to the end of the piston rod 1331 near the first end cap 134 or the bottom of the first piston cylinder 1332; the second buffer pad 136 is located between the end of the first piston cylinder 1332 near the first end cap 134 and the bottom of the outer cylinder 132, and the second buffer pad 136 is fixedly connected to the end of the first piston cylinder 1332 near the first end cap 134 or the bottom of the outer cylinder 132.

[0077] The first multi-stage cylinder 13 and the second multi-stage cylinder 14 may each include a third buffer pad 137 and a second end cap 138. The third buffer pad 137 is arranged around the end of the first piston cylinder 1332. For example, when the first multi-stage cylinder 13 is in the extended state, the third buffer pad 137 may be located between the end of the first piston cylinder 1332 and the second end cap 138.

[0078] Thus, by placing multiple buffer pads in the areas where the multi-stage piston 133 may come into contact with each other during the switching process, and utilizing the compressibility of the buffer pads to create a transition section, the vibration caused by pressure fluctuations due to area changes during the multi-stage cylinder switching process can be reduced.

[0079] Please refer to Figure 1 and Figure 2 In an optional embodiment, the active regulating circuit 11 may further include: a one-way inlet speed regulating valve 113, a one-way return throttle valve 114, and a first balance valve 115. The one-way inlet speed regulating valve 113 and the one-way return throttle valve 114 are connected in series on the first connecting oil passage 112. Both working ports of the first balance valve 115 are connected to the first connecting oil passage 112, and the control port of the first balance valve 115 is connected to the other working port of the first directional valve 111. The driven regulating circuit 12 further includes: a second balance valve 123. Both working ports of the second balance valve 123 are connected to the second connecting oil passage 122, and the control port of the second balance valve 123 is connected to the other working port of the proportional directional valve 121.

[0080] In this system, because the load changes significantly during the ascent of the hydraulic synchronous drive system and is typically smaller during the descent, the active adjustment circuit 11 employs a directional valve in conjunction with a one-way inlet speed control valve 113 and a one-way return throttle valve 114 to ensure stable system speed under different load conditions. Furthermore, the active adjustment circuit 11 and the driven adjustment circuit 12 respectively ensure the stability of the load descent through a first balance valve 115 and a second balance valve 123, preventing load runaway and ensuring smooth movement.

[0081] Please refer to Figure 1 and Figure 2 In an optional embodiment, the hydraulic synchronous drive system may further include a first throttle valve 161, a second throttle valve 162, and a ball valve 163. The liquid storage assembly 15 includes an oil reservoir 151, an oil outlet line 152, and an oil return line 153. The first throttle valve 161 is connected to the first end of the first multi-stage cylinder 13 and the first end of the ball valve 163, respectively. The second throttle valve 162 is connected to the first end of the second multi-stage cylinder 14 and the first end of the ball valve 163, respectively. The second end of the ball valve 163 is connected to the oil return line 153. Both the oil return line 153 and the oil outlet line 152 are connected to the oil reservoir 151.

[0082] By setting the first throttle valve 161, the second throttle valve 162, and the ball valve 163, the emergency lowering speed of the hydraulic synchronous drive system is controlled in the form of a double switch, so as to avoid the impact of single valve leakage on the system pressure holding under normal working conditions, and so that the load can still be safely lowered when the hydraulic synchronous drive system fails in the event of power failure.

[0083] In one exemplary embodiment, a pipeline explosion-proof valve 164 is provided at the oil port of both the first multi-stage hydraulic cylinder 13 and the second multi-stage hydraulic cylinder 14 to prevent uncontrollable descent of the platform due to pipeline damage. Simultaneously, an exhaust port k4 is provided at the highest point of both the first multi-stage hydraulic cylinder 13 and the second multi-stage hydraulic cylinder 14 to prevent internal gas from affecting the stability of the system's movement.

[0084] Please refer to Figure 1 and Figure 2In an optional embodiment, the hydraulic synchronous drive system may further include: a loading circuit 17, an auxiliary adjustment circuit 18, and an auxiliary cylinder 19; the loading circuit 17 includes a full unloading valve 171, a proportional relief valve 172, and a pressure limiting relief valve 173, all of which are connected to the outlet line 152 and the return line 153, respectively; the auxiliary adjustment circuit 18 includes a second directional valve 181 and two one-way throttle valves 182, the inlet of the second directional valve 181 being connected to the outlet line 152, the outlet of the second directional valve 181 being connected to the return line 153, and the two working ports of the second directional valve 181 being connected to the auxiliary cylinder 19 via the two one-way throttle valves 182. For example, the hydraulic synchronous drive system may include two auxiliary adjustment circuits 18.

[0085] By associating the control signal of the proportional relief valve 172 with the control signals of the first directional valve 111, the proportional directional valve 121, and the second directional valve 181, the state of the proportional relief valve 172 can be adjusted according to the state of different valves. For example, when the active adjustment circuit 11 and the driven adjustment circuit 12 drive the first multi-stage cylinder 13 and the second multi-stage cylinder 14, the proportional relief valve 172 is in a first open state. When the auxiliary adjustment circuit 18 drives the auxiliary cylinder 19, the proportional relief valve 172 is in a second open state. The flow rate of the proportional relief valve 172 in the first open state and the flow rate in the second open state can be different. Furthermore, in this embodiment of the invention, the active adjustment circuit 11 and the driven adjustment circuit 12 may not be activated simultaneously with the auxiliary adjustment circuit 18, and the loads of the first multi-stage cylinder 13 and the second multi-stage cylinder 14 may be different from the load of the auxiliary cylinder 19.

[0086] Thus, the proportional relief valve 172 can meet the different pressure settings of different cylinders, thereby reducing power loss. Simultaneously, the control component can control the proportional relief valve 172 via a ramp signal to reduce pressure shocks in the hydraulic synchronous drive system during unloading. Furthermore, when the ambient temperature and hydraulic oil temperature are low, resulting in excessively high hydraulic oil viscosity, the hydraulic synchronous drive system is set to a low-pressure state when the control component can be started. In this low-pressure state, the flow rate of the proportional relief valve 172 is typically small, thus preventing damage to the oil pump 154 ​​in the reservoir assembly 15 from operating under high loads at unsuitable hydraulic oil viscosity. Simultaneously, when the proportional relief valve 172 is open, some hydraulic oil flows back to the oil reservoir 151 in the reservoir assembly 15 through the proportional relief valve 172. The overflow process converts the energy output by the oil pump 154 ​​into heat energy, causing the hydraulic oil temperature to rise. Therefore, hydraulic oil can be uniformly heated through hydraulic overflow heating, which avoids the problem of rapid deterioration of hydraulic oil caused by high-temperature heating compared to heating hydraulic oil with a high-power heater 159.

[0087] Furthermore, the power loss of the hydraulic synchronous drive system in standby mode is reduced by the full unloading valve 171, and the peak pressure of the hydraulic synchronous drive system is ensured not to exceed the limit by the pressure limiting relief valve 173. The pressure limiting relief valve 173 can also limit the maximum pressure of the system after the proportional relief valve 172 fails.

[0088] Please refer to Figure 7 , Figure 7 yes Figure 1 The schematic diagram of the hydraulic synchronous drive system shown illustrates the structure of the reservoir component 15. In an optional embodiment, the reservoir component 15 may further include an oil pump 154, a cooler 155, two filters 156, a temperature sensor 157, a dryer breather 158, a heater 159, and an outlet check valve 15a. The oil pump 154 ​​is installed on the oil outlet line 152, the cooler 155 is installed on the oil return line 153, and the two filters 156 are respectively installed on the oil outlet line 152 and the oil return line 153. The temperature sensor 157, the dryer breather 158, and the heater 159 are all installed on the oil reservoir 151, and the outlet check valve 15a is located at the oil outlet of the oil pump 154. Furthermore, the oil reservoir 151 also has an isolation plate 1511 inside, the extension direction of which intersects with the flow direction of the hydraulic oil in the oil reservoir 151.

[0089] By installing filters 156 at the outlet of the oil pump 154 ​​and on the return oil line 153, the cleanliness of the hydraulic synchronous drive system can be improved. An isolation plate 1511 is installed inside the oil reservoir 151, dividing the reservoir 151 into a clean area and a return oil area. The hydraulic oil in the return oil area must pass through the isolation plate of a certain height to enter the clean area, thereby reducing iron filings and air bubbles that flow directly to the suction port of the oil pump 154.

[0090] The heater 159 can be a low-power heater 159. By installing a low-power heater 159 and a dryer breather 158 on the oil reservoir 151, the internal temperature of the oil reservoir 151 can be higher than that of the environment without affecting the quality of the hydraulic oil. This reduces the exchange of gas between the oil reservoir 151 and the ambient gas, thereby reducing the generation of condensate inside the oil reservoir. The dryer breather 158 can further filter and dry the gas entering the oil reservoir to reduce the water content of the gas.

[0091] In summary, this utility model embodiment provides a hydraulic synchronous drive system including an active adjustment circuit 11, a driven adjustment circuit 12, a first multi-stage cylinder 13, a second multi-stage cylinder 14, a liquid storage component 15, and a control component. The first multi-stage cylinder 13 (i.e., the main hydraulic cylinder) is controlled by a directional valve, and the second multi-stage cylinder 14 (i.e., the slave hydraulic cylinder) is controlled by a proportional directional valve 121. The control component can detect the positions of the first multi-stage cylinder 13 and the second multi-stage cylinder 14 respectively through two rope displacement sensors 131, and adjust the control signal of the proportional directional valve 121 according to the feedback signals of the two rope displacement sensors 131, so that the second multi-stage cylinder 14 follows the movement of the first multi-stage cylinder 13 to achieve synchronous lifting and lowering. In this way, the position or speed of the first multi-stage cylinder 13 and the second multi-stage cylinder 14 can be kept consistent, which can improve the synchronization accuracy of the hydraulic synchronous drive system and solve the problem of low stability of hydraulic synchronous drive systems in related technologies.

[0092] Please refer to Figure 1 and Figure 8 , Figure 8 This is a schematic diagram of the structure of an unloading platform provided in an embodiment of the present utility model. The unloading platform may include: a bearing platform 21, a hydraulic synchronous drive system 22, a first rotating seat 23 and a second rotating seat 24. The hydraulic synchronous drive system 22 includes the hydraulic synchronous drive system in any of the above embodiments. One end of the bearing platform 21 is connected to the first multi-stage cylinder 13 and the second multi-stage cylinder 14 in the hydraulic synchronous drive system 22. Both the first multi-stage cylinder 13 and the second multi-stage cylinder 14 are connected to the first rotating seat 23. The second end of the bearing platform 21 is connected to the second rotating seat 24.

[0093] This unloading platform can be used for unloading vehicles 31. For example, it can be applied to container trucks that are not equipped with self-unloading systems, have large tonnage, and require fast unloading. It can improve unloading efficiency and ensure a safe and stable unloading process, significantly improving the safety of vehicles 31, goods, and personnel.

[0094] In one exemplary embodiment, the unloading platform may further include: a platform tilt angle measuring sensor; the control component may include a PLC control system, which detects the displacement difference between the first multi-stage cylinder 13 and the second multi-stage cylinder 14 through two rope displacement sensors 131 and the platform tilt angle measuring sensor, and compares them to ensure signal accuracy and platform control safety; the PLC control system controls the opening degree of the proportional valve directional valve through multiple detection signals.

[0095] For example, when the hydraulic synchronous drive system 22 needs to be started, the control component sets the pressure of the proportional relief valve 172 according to the adjustment circuit that needs to be opened. For example, when the unloading platform needs to be raised or lowered by the first multi-stage cylinder 13 and the second multi-stage cylinder 14, the proportional relief valve 172 is set to a preset pressure value. At the same time, the directional valve is controlled to move. The PLC control system outputs a corresponding control signal to the proportional directional valve 121 by detecting the tilt of the platform and the position deviation of the cylinder, thereby controlling the first multi-stage cylinder 13 and the second multi-stage cylinder 14 to rise or fall synchronously, so that the unloading platform can operate smoothly.

[0096] Furthermore, the low-power heater 159 in the oil reservoir 151 can be turned on for a long time, thereby keeping the air inside the oil reservoir 151 dry. After passing through the filter 156, the hydraulic oil is guaranteed to be self-cleaning during use, and the sedimentation effect in the oil reservoir 151 reduces bubbles and impurities, which can improve the cleanliness and dryness of the hydraulic oil in the hydraulic synchronous drive system 22 and improve the reliability of the hydraulic synchronous drive system 22.

[0097] In one exemplary embodiment, the auxiliary cylinder 19 can be used to hold the rear wheels of the vehicle 31 in place, preventing the vehicle 31 from sliding after the lifting platform is raised, thereby improving the safety, efficiency and high tilt performance of the hydraulic synchronous drive system 22.

[0098] It should be noted that the dimensions of the areas may have been exaggerated in the accompanying drawings for clarity. Furthermore, it is understood that when an element is referred to as "on top of" another element, it can be directly on the other element, or there may be intermediate elements. Additionally, it is understood that when an element is referred to as "below" another element, it can be directly below the other element, or there may be more than one intermediate element. Furthermore, it is also understood that when an element is referred to as "between" two elements, it can be the only layer between the two elements, or there may be more than one intermediate element. Similar reference numerals throughout indicate similar elements.

[0099] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.

[0100] The above description is only an optional embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A hydraulic synchronous drive system, characterized in that, include: Active regulating circuit, driven regulating circuit, first multi-stage hydraulic cylinder, second multi-stage hydraulic cylinder, liquid storage assembly and control assembly; The active adjustment circuit includes a first reversing valve and a first connecting oil circuit. The oil inlet and oil outlet of the first reversing valve are both connected to the liquid storage component. One working oil port of the first reversing valve is connected to the first multi-stage oil cylinder through the first connecting oil circuit. The driven adjustment circuit includes a proportional directional valve and a second connecting oil circuit. The inlet and outlet of the proportional directional valve are both connected to the liquid storage component. One working port of the proportional directional valve is connected to the second multi-stage cylinder through the second connecting oil circuit. Both the first multi-stage hydraulic cylinder and the second multi-stage hydraulic cylinder are equipped with a rope displacement sensor, which is used to detect the position of the piston rod in the first multi-stage hydraulic cylinder and the second multi-stage hydraulic cylinder; The control component is electrically connected to the rope displacement sensor, the first directional valve, and the proportional directional valve, respectively.

2. The hydraulic synchronous drive system according to claim 1, characterized in that, Both the first multi-stage hydraulic cylinder and the second multi-stage hydraulic cylinder include: an outer cylinder barrel, a multi-stage piston, a first end cap, and the rope displacement sensor; The multi-stage piston is located in the outer cylinder, and the multi-stage piston includes a piston rod and at least one piston cylinder nested outside the piston rod; The first end cap is fixedly connected to one end of the outer cylinder. The first end cap has a receiving cavity, and the receiving cavity has a first opening on the side facing the outer cylinder. The rope displacement sensor has a pull rope, at least a portion of which is located in the accommodating cavity, and one end of the pull rope is connected to the end of the piston rod through the first opening.

3. The hydraulic synchronous drive system according to claim 2, characterized in that, The rope displacement sensor includes a drive motor, a rotating shaft, a drum, the pull rope, and an encoder. The first end cap has a first mounting through hole, which communicates with the accommodating cavity. The drive motor is located outside the first mounting through hole and is mounted on the first end cover. The reel mechanism is installed in the accommodating cavity of the first end cap. The rotating shaft passes through the first mounting through hole, and both ends of the rotating shaft are respectively connected to the drive motor and the drum; At least a portion of the pull rope is wound around the drum; The encoder is electrically connected to both the drive motor and the control component.

4. The hydraulic synchronous drive system according to claim 3, characterized in that, The rope displacement sensor also includes a drum support and a pressure ring structure; The roll support is fixedly installed on the inner wall of the accommodating cavity of the first end cover. The drum is mounted on the drum support and is rotatably connected to the drum support. The surface of the drum has a plurality of annular guide grooves, which are arranged along the axial direction of the drum. The pressure ring structure is located on one side of the drum and is fixedly connected to the drum support. The pressure ring structure is used to guide the pull rope into or out of the annular guide groove.

5. The hydraulic synchronous drive system according to claim 2, characterized in that, The at least one piston cylinder includes a first piston cylinder, and the first multi-stage hydraulic cylinder and the second multi-stage hydraulic cylinder each further include: a first buffer pad and a second buffer pad; The first buffer pad is located between the end of the piston rod near the first end cap and the bottom of the first piston cylinder, and the first buffer pad is fixedly connected to the end of the piston rod near the first end cap or the bottom of the first piston cylinder; The second buffer pad is located between the end of the first piston cylinder near the first end cap and the bottom of the outer cylinder, and the second buffer pad is fixedly connected to the end of the first piston cylinder near the first end cap or the bottom of the outer cylinder.

6. The hydraulic synchronous drive system according to any one of claims 1-5, characterized in that, The active adjustment circuit further includes: a one-way inlet speed control valve, a one-way return throttle valve, and a first balance valve. The one-way inlet speed control valve and the one-way return throttle valve are connected in series in the first connecting oil circuit. Both working oil ports of the first balance valve are connected to the first connecting oil circuit. The control oil port of the first balance valve is connected to the other working oil port of the first reversing valve. The driven adjustment circuit further includes: a second balance valve, both working ports of the second balance valve are connected to the second connecting oil circuit, and the control port of the second balance valve is connected to the other working port of the proportional directional valve.

7. The hydraulic synchronous drive system according to claim 6, characterized in that, The hydraulic synchronous drive system also includes a first throttle valve, a second throttle valve, and a ball valve, and the liquid storage assembly includes an oil reservoir, an oil outlet line, and an oil return line; The first throttle valve is connected to the first end of the first multi-stage hydraulic cylinder and the first end of the ball valve, respectively; The second throttle valve is connected to the first end of the second multi-stage hydraulic cylinder and the ball valve, respectively; The second end of the ball valve is connected to the return oil pipeline; Both the return oil line and the outlet oil line are connected to the oil storage tank.

8. The hydraulic synchronous drive system according to claim 7, characterized in that, The hydraulic synchronous drive system also includes: a loading circuit, an auxiliary adjustment circuit, and an auxiliary cylinder; The loading circuit includes a full unloading valve, a proportional relief valve, and a pressure limiting relief valve. The full unloading valve, the proportional relief valve, and the pressure limiting relief valve are all connected to the oil outlet line and the oil return line, respectively. The auxiliary regulating circuit includes a second reversing valve and two one-way throttle valves. The oil inlet of the second reversing valve is connected to the oil outlet pipeline, and the oil outlet of the second reversing valve is connected to the oil return pipeline. The two working oil ports of the second reversing valve are respectively connected to the auxiliary oil cylinder through the two one-way throttle valves.

9. The hydraulic synchronous drive system according to claim 7, characterized in that, The liquid storage assembly also includes an oil pump, a cooler, two filters, a temperature sensor, a dryer breather, and a heater; The oil pump is installed on the oil outlet pipeline, the cooler is installed on the oil return pipeline, and the two filters are installed on the oil outlet pipeline and the oil return pipeline, respectively. The temperature sensor, the drying breather, and the heater are all mounted on the oil tank. Furthermore, the oil tank has an internal isolation plate whose extension direction intersects with the hydraulic oil flow direction within the oil tank.

10. A loading platform, characterized in that, include: The platform includes a hydraulic synchronous drive system, a first rotating seat, and a second rotating seat, wherein the hydraulic synchronous drive system comprises the hydraulic synchronous drive system according to any one of claims 1 to 9; One end of the bearing platform is connected to the first multi-stage cylinder and the second multi-stage cylinder in the hydraulic synchronous drive system. Both the first multi-stage cylinder and the second multi-stage cylinder are connected to the first rotating seat. The second end of the bearing platform is connected to the second rotating seat.

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