Hydraulic synchronous driving system and unloading platform

Abstract

The invention 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] The present application relates to the field of hydraulic lifting technology, and in particular to a hydraulic synchronous drive system and an unloading platform. Background Art

[0002] With the development of logistics technology, the logistics industry has higher and higher requirements for efficiency and safety. At present, most logistics transport vehicles do not include self-unloading devices. If manual unloading is carried out with auxiliary tools such as forklifts, the unloading process is inefficient, especially for bulk goods. Therefore, the unloading platform can be used to change the posture of the entire logistics transport vehicle to unload the entire vehicle as a whole and improve logistics efficiency.

[0003] The unloading platform usually adopts a hydraulic synchronous drive system to control the lifting process of the platform. The hydraulic synchronous drive system may include two multi-stage cylinders and a diverter to lift the unloading platform by a double-sided jacking method, and the two multi-stage cylinders are synchronously controlled by the diverter.

[0004] However, since the diversion accuracy of the diverter is greatly affected by the load, the diversion accuracy of the diverter will also be affected for multi-stage cylinders with a long stroke, causing uneven loads on each cylinder and large synchronization errors, resulting in low stability of the hydraulic synchronous drive system. Summary of the invention

[0005] The embodiment of the present application provides a hydraulic synchronous drive system and a cargo unloading platform, which can solve the problem of low stability of the hydraulic synchronous drive system in the prior art. The technical solution is as follows:

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

[0007] The active regulating circuit comprises a first reversing valve and a first connecting oil circuit, the oil inlet and the oil outlet of the first reversing valve are both connected to the liquid storage assembly, and a 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 regulating circuit comprises a proportional reversing valve and a second connecting oil circuit, the oil inlet and the oil outlet of the proportional reversing valve are both connected to the liquid storage assembly, and a working oil port of the proportional reversing valve is connected to the second multi-stage oil cylinder through the second connecting oil circuit;

[0009] The first multi-stage oil cylinder and the second multi-stage oil cylinder each have a rope-type displacement sensor, and the rope-type displacement sensor is used to detect the position of the piston rod in the first multi-stage oil cylinder and the second multi-stage oil cylinder;

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

[0011] Optionally, the first multi-stage oil cylinder and the second multi-stage oil cylinder each include: an outer cylinder barrel, a multi-stage piston, a first end cover portion and the rope-type 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 cover is fixedly connected to one end of the outer cylinder, and the first end cover has a receiving cavity, and the receiving cavity has a first opening on a side facing the outer cylinder;

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

[0015] Optionally, the rope-type displacement sensor comprises a driving motor, a rotating shaft, a reel, the pull rope and an encoder, and the first end cover has a first mounting through hole, and the first mounting through hole is communicated with the accommodating cavity;

[0016] The driving 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 cover portion;

[0018] The rotating shaft is inserted into the first mounting through hole, and two ends of the rotating shaft are respectively connected to the driving motor and the reel;

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

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

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

[0022] The reel support is fixedly mounted on the inner wall of the accommodating cavity of the first end cover portion;

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

[0024] The pressure ring structure is located at one side of the reel and is fixedly connected to the reel support. The pressure ring structure is used to guide the pull rope to enter or leave the annular guide groove.

[0025] Optionally, the at least one piston cylinder includes a first piston cylinder, and the first multi-stage oil cylinder and the second multi-stage oil 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 close to the first end cover and the bottom of the first piston cylinder, and the first buffer pad is fixedly connected to the end of the piston rod close to the first end cover or the bottom of the first piston cylinder;

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

[0028] Optionally, the active regulation circuit further includes: a one-way oil inlet speed regulating valve, a one-way oil return throttle valve and a first balancing valve, wherein the one-way oil inlet speed regulating valve and the one-way oil return throttle valve are arranged in series on the first connecting oil circuit, two working oil ports of the first balancing valve are both connected to the first connecting oil circuit, and a control oil port of the first balancing valve is connected to another working oil port of the first reversing valve;

[0029] The driven regulating circuit also includes: a second balancing valve, both working oil ports of the second balancing valve are connected to the second connecting oil circuit, and the control oil port of the second balancing valve is connected to another working oil port of the proportional reversing valve.

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

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

[0032] The second throttle valve is communicated with the second multi-stage oil cylinder and the first end of the ball valve respectively;

[0033] The second end of the ball valve is in communication with the oil return pipeline;

[0034] The oil return pipeline and the oil outlet pipeline are both communicated with the oil storage tank.

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

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

[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, the oil outlet of the second reversing valve is connected to the oil return pipeline, and 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 comprises an oil transfer pump, a cooler, two filters, a temperature sensor, a dry respirator and a heater;

[0039] The oil delivery 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 dry respirator and the heater are all installed on the oil storage tank, and the oil storage tank is further provided with an isolation plate inside, and the extension direction of the isolation plate intersects with the flow direction of the hydraulic oil in the oil storage tank.

[0041] According to another aspect of the present application, there is provided a loading platform, comprising: a load-bearing platform, 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 described above;

[0042] One end of the carrying platform is connected to the first multi-stage oil cylinder and the second multi-stage oil cylinder in the hydraulic synchronous drive system, and the first multi-stage oil cylinder and the second multi-stage oil cylinder are both connected to the first rotating seat;

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

[0044] The beneficial effects brought by the technical solution provided by the embodiment of the present application include at least:

[0045] The embodiment of the present application provides a hydraulic synchronous drive system including an active adjustment circuit, a passive adjustment circuit, a first multi-stage oil cylinder, a second multi-stage oil cylinder, a liquid storage component and a control component. The first multi-stage oil cylinder (also known as the master hydraulic cylinder) is controlled by a reversing valve, and the second multi-stage oil cylinder (also known as the slave hydraulic cylinder) is controlled by a proportional reversing valve. The control component can detect the positions of the first multi-stage oil cylinder and the second multi-stage oil cylinder respectively through two rope-type displacement sensors, and adjust the control signal of the proportional reversing valve according to the feedback signals of the two rope-type displacement sensors, so that the second multi-stage oil cylinder follows the movement of the first multi-stage oil cylinder to achieve synchronous lifting; in this way, it can ensure that the positions or speeds of the first multi-stage oil cylinder and the second multi-stage oil cylinder remain consistent, the synchronization accuracy of the hydraulic synchronous drive system can be improved, and the problem of low stability of the hydraulic synchronous drive system in the related art can be solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

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

[0048] Figure 2 yes Figure 1 A schematic diagram of a circuit portion in the principle schematic diagram of the hydraulic synchronous drive system shown;

[0049] Figure 3 It is a structural schematic diagram of a first multi-stage oil cylinder provided in an embodiment of the present application;

[0050] Figure 4 yes Figure 3 The schematic diagram of the cross-sectional structure of the first multi-stage oil cylinder along the position A1-A2 shown;

[0051] Figure 5 It is a structural schematic diagram of a rope-type displacement sensor provided in an embodiment of the present application;

[0052] Figure 6 yes Figure 5 A schematic diagram of a local B1 structure of the rope-type displacement sensor shown;

[0053] Figure 7 yes Figure 1 A schematic diagram of the structure of the liquid storage component in the principle schematic diagram of the hydraulic synchronous drive system shown;

[0054] Figure 8It is a structural schematic diagram of an unloading platform provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0056] Although the present application can be easily presented as embodiments of different forms, only some of the specific embodiments are shown in the drawings and described in detail in this specification. It should be understood that this description should be regarded as an exemplary description of the principles of the present application and is not intended to limit the present application to that described herein.

[0057] Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the application, rather than implying that each embodiment of the application must have the described features. In addition, it should be noted that this specification describes many features. Although some features can be combined together to illustrate possible system designs, these features can also be used for other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0058] In the embodiments shown in the drawings, the indications of directions (such as up, down, left, right, front and back) used to explain the structure and movement of various elements of the present application are not absolute but relative. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the description of the positions of these elements changes, the indications of these directions also change accordingly.

[0059] Please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 , Figure 1 is a schematic diagram of the principle of a hydraulic synchronous drive system provided in an embodiment of the present application, Figure 2 yes Figure 1 The schematic diagram of the circuit part in the principle schematic diagram of the hydraulic synchronous drive system shown in FIG. Figure 3 is a structural schematic diagram of a first multi-stage oil cylinder 13 provided in an embodiment of the present application, Figure 4 yes Figure 3 The cross-sectional structural diagram of the first multi-stage cylinder 13 along the position A1-A2 is shown, and the hydraulic synchronous drive system may include: an active regulating circuit 11, a driven regulating circuit 12, a first multi-stage cylinder 13, a second multi-stage cylinder 14, a liquid storage component 15 and a control component (not shown in the figure), wherein the active regulating circuit 11 is used to adjust the telescopic state of the first multi-stage cylinder 13, the driven regulating circuit 12 is used to adjust the telescopic state of the second multi-stage cylinder 14, and the liquid storage component 15 is used to store and provide hydraulic oil.

[0060] The active regulating circuit 11 may include a first reversing valve 111 and a first connecting oil circuit 112. The oil inlet and the oil outlet of the first reversing valve 111 are both connected to the liquid storage assembly 15. One working oil port of the first reversing valve 111 is connected to the first multi-stage oil cylinder 13 through the first connecting oil circuit 112. The first reversing valve 111 can control the telescopic movement of the first multi-stage oil cylinder 13 by changing the flow direction of the hydraulic oil. That is, by controlling the valve core position of the first reversing valve 111, the movement state (such as extension, retraction or stop) of the first multi-stage oil cylinder 13 can be controlled. Exemplarily, the first reversing valve 111 may include a three-position four-way electromagnetic reversing valve, and the first multi-stage oil cylinder 13 may include a plunger hydraulic cylinder. The plunger hydraulic cylinder is a single-acting hydraulic cylinder and may have an oil port that can be used to connect to the first connecting oil circuit 112. The first multi-stage oil cylinder 13 can rely on hydraulic oil to push the multi-stage piston 133 to extend and rely on external force (such as gravity or spring) to retract.

[0061] The slave regulating circuit 12 may include a proportional reversing valve 121 and a second connecting oil circuit 122. The oil inlet and the oil outlet of the proportional reversing valve 121 are both connected to the liquid storage assembly 15. A working oil port of the proportional reversing valve 121 is connected to the second multi-stage oil cylinder 14 through the second connecting oil circuit 122. The proportional reversing valve 121 can control the flow direction of the hydraulic oil and the flow rate of the hydraulic oil. Exemplarily, the proportional reversing valve 121 may include a three-position four-way electromagnetic proportional reversing valve 121, and the second multi-stage oil cylinder 14 may include a plunger hydraulic cylinder.

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

[0063] In the embodiment of the present application, the master-slave control method is adopted to realize the synchronous control of the first multi-stage oil cylinder 13 and the second multi-stage oil cylinder 14. Exemplarily, the first multi-stage oil cylinder 13 (that is, the master hydraulic cylinder) is controlled by the reversing valve, and the second multi-stage oil cylinder 14 (that is, the slave hydraulic cylinder) is controlled by the proportional reversing valve 121. The control component can detect the positions of the first multi-stage oil cylinder 13 and the second multi-stage oil cylinder 14 through the rope displacement sensor 131, and adjust the control signal of the proportional reversing valve 121 according to the feedback signal of the rope displacement sensor 131, so that the second multi-stage oil cylinder 14 follows the movement of the first multi-stage oil cylinder 13 to realize synchronous lifting; in this way, it can ensure that the positions or speeds of the first multi-stage oil cylinder 13 and the second multi-stage oil cylinder 14 are consistent, and the synchronization accuracy of the hydraulic synchronous drive system can be improved.

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

[0065] In summary, the embodiment of the present application provides a hydraulic synchronous drive system including an active regulation circuit 11, a passive regulation circuit 12, a first multi-stage oil cylinder 13, a second multi-stage oil cylinder 14, a liquid storage component 15 and a control component. The first multi-stage oil cylinder 13 (also known as the master hydraulic cylinder) is controlled by a reversing valve, and the second multi-stage oil cylinder 14 (also known as the slave hydraulic cylinder) is controlled by a proportional reversing valve 121. The control component can detect the positions of the first multi-stage oil cylinder 13 and the second multi-stage oil cylinder 14 respectively through two rope-type displacement sensors 131, and adjust the control signal of the proportional reversing valve 121 according to the feedback signals of the two rope-type displacement sensors 131, so that the second multi-stage oil cylinder 14 follows the movement of the first multi-stage oil cylinder 13 to achieve synchronous lifting; in this way, it can ensure that the positions or speeds of the first multi-stage oil cylinder 13 and the second multi-stage oil cylinder 14 are consistent, the synchronization accuracy of the hydraulic synchronous drive system can be improved, and the problem of low stability of the hydraulic synchronous drive system in the related art can be solved.

[0066] Please refer to Figure 4 In an optional embodiment, the first multi-stage oil cylinder 13 and the second multi-stage oil cylinder 14 both include: an outer cylinder 132, a multi-stage piston 133, a first end cover 134 and a rope displacement sensor 131. Figure 4 Taking the first multi-stage oil cylinder 13 as an example, the second multi-stage oil cylinder 14 and the first multi-stage oil cylinder 13 may have the same structure.

[0067] The multi-stage piston 133 is located in the outer cylinder 132, and 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. The first end cover 134 is fixedly connected to one end of the outer cylinder 132, and the first end cover 134 has a receiving chamber c1, and the receiving chamber c1 has a first opening k1 on the side facing the outer cylinder 132; the rope displacement sensor 131 has a pull rope 1311, at least part of the pull rope 1311 is located in the receiving portion, one end of the pull rope 1311 is connected to the end of the piston rod 1331 through the first opening k1, and one end of the pull rope 1311 can be fixedly connected to one end of the piston rod 1331 close to the first end cover 134. When the first multi-stage oil cylinder 13 is working, the piston rod 1331 can move along the length direction of the outer cylinder barrel 132. When the piston rod 1331 moves, it can drive the pull rope 1311 to move, so as to obtain the telescopic position of the first multi-stage oil cylinder 13 through the rope displacement sensor 131. By arranging the pull rope 1311 of the rope displacement sensor 131 inside the first end cover portion 134 of the first multi-stage oil cylinder 13 and the outer cylinder barrel 132, the interference of foreign matter 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 is a structural schematic diagram of a rope-type displacement sensor 131 provided in an embodiment of the present application, Figure 5The figure shows the state of the rope displacement sensor 131 installed on the first end cover part 134. In an optional embodiment, the rope displacement sensor 131 includes a driving motor 1312, a rotating shaft 1313, a drum 1314, a pull rope 1311 and an encoder 1315. The first end cover part 134 has a first mounting through hole k2, and the first mounting through hole k2 is connected to the accommodating chamber c1; the driving motor 1312 is located outside the first mounting through hole k2 and is installed on the first end cover part 134; the drum 1314 mechanism is installed in the accommodating chamber c1 of the first end cover part 134; the rotating shaft 1313 is passed through the first mounting through hole k2, and the two ends of the rotating shaft 1313 are respectively connected to the driving motor 1312 and the drum 1314; at least a part of the pull rope 1311 is wound on the drum 1314; the encoder 1315 is electrically connected to the driving motor 1312 and the control component respectively. By winding the pull rope 1311 on the reel 1314 and driving the reel 1314 to rotate by the driving motor 1312, the linear displacement of the piston rod 1331 can be converted into the rotational displacement of the reel 1314. The rotational displacement of the reel 1314 is converted into an electrical signal by the encoder 1315. Exemplarily, when the pull rope 1311 is pulled or released, the reel 1314 will rotate accordingly, and the encoder 1315 can calculate the linear displacement of the pull rope 1311 by detecting the rotation angle or number of turns of the reel 1314, thereby obtaining the displacement of the piston rod 1331. The encoder 1315 can be electrically connected to the control component to transmit the detected position information to the control component.

[0069] like Figure 5 As shown, in an exemplary embodiment, the driving 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 rotating seal 1318, a support ring 1319 and a reel support 131a; the flange support 1316 may be fixedly mounted on the outer side 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, and the output shaft of the drive motor 1312 may pass through the second mounting through hole k3 of the flange support 1316 and be fixedly connected to the rotating shaft 1313. Exemplarily, the rotating shaft 1313 has a first end and a second end opposite to each other, the first end may be connected to the drive motor 1312, and the second end may be fixedly connected to the reel 1314. The first end of the rotating shaft 1313 has a first groove c2, and the output shaft of the drive motor 1312 may extend into the first groove c2 and be fixedly connected to the rotating shaft 1313, and the output shaft of the drive motor 1312 may be threadedly connected or clamped to 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 rotating seal 1318 and the supporting ring 1319 can 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 rotating seal 1318 and the supporting ring 1319 can be embedded in the hole wall of the first mounting through hole k2.

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

[0074] Please refer to Figure 6 , Figure 6 yes Figure 5 A schematic diagram of the local B1 structure of the rope displacement sensor 131 is shown. In an optional embodiment, the rope displacement sensor 131 may also include a pressure ring structure 131b, and 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, and the pressure ring structure 131b is used to guide the pull rope 1311 to enter or leave the annular guide groove c4.

[0075] The drum support 131a may have a rope threading hole, and the pull rope 1311 may pass through the rope threading hole 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 hole wall of the rope threading hole and surround the pull rope 1311. The bearing sleeve 131c may reduce the friction coefficient 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 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 oil cylinder 13 and the second multi-stage oil cylinder 14 may also 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 close to the first end cover portion 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 close to the first end cover portion 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 close to the first end cover portion 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 close to the first end cover portion 134 or the bottom of the outer cylinder 132.

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

[0078] In this way, by setting multiple buffer pads in areas where the multi-stage piston 133 may contact each other during the switching process, and using the compressibility of the buffer pads to produce a transition section, the jitter caused by pressure changes due to area changes during the multi-stage cylinder shifting process can be reduced.

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

[0080] Among them, since the load of the hydraulic synchronous drive system changes greatly during the ascending process and is usually smaller during the descending process, the active regulating circuit 11 uses a reversing valve in conjunction with a one-way oil inlet speed regulating valve 113 and a one-way oil return throttle valve 114 to ensure the stable operating speed of the system under different loads. In addition, the active regulating circuit 11 and the driven regulating circuit 12 respectively ensure the stability of the negative load descent through the first balancing valve 115 and the second balancing valve 123, prevent the load from getting out of control, and ensure 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, and the liquid storage assembly 15 includes an oil storage tank 151, an oil outlet pipeline 152 and an oil return pipeline 153; the first throttle valve 161 is respectively connected to the first end of the first multi-stage cylinder 13 and the ball valve 163; the second throttle valve 162 is respectively connected to the second multi-stage cylinder 14 and the first end of the ball valve 163; the second end of the ball valve 163 is connected to the return oil pipeline 153; the return oil pipeline 153 and the oil outlet pipeline 152 are both connected to the oil storage tank 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 controllable in the form of a double switch, so as to avoid the influence of a single valve leakage on the system pressure maintenance under normal working conditions, so that the load of the hydraulic synchronous drive system can still be safely lowered when the power fails.

[0083] In an exemplary embodiment, pipeline explosion-proof valves 164 are provided at the oil ports of the first multi-stage oil cylinder 13 and the second multi-stage oil cylinder 14 to prevent the platform from falling uncontrollably due to pipeline damage. At the same time, exhaust ports k4 are provided at the highest points of the first multi-stage oil cylinder 13 and the second multi-stage oil cylinder 14 to prevent the gas inside the oil cylinder from affecting the stability of the system 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 regulating circuit 18 and an auxiliary oil cylinder 19; the loading circuit 17 includes a full unloading valve 171, a proportional relief valve 172 and a pressure limiting relief valve 173, and the full unloading valve 171, the proportional relief valve 172 and the pressure limiting relief valve 173 are respectively connected to the oil outlet pipeline 152 and the oil return pipeline 153; the auxiliary regulating circuit 18 includes a second reversing valve 181 and two one-way throttle valves 182, the oil inlet of the second reversing valve 181 is connected to the oil outlet pipeline 152, the oil outlet of the second reversing valve 181 is connected to the oil return pipeline 153, and the two working oil ports of the second reversing valve 181 are respectively connected to the auxiliary oil cylinder 19 through the two one-way throttle valves 182. Exemplarily, the hydraulic synchronous drive system may include two auxiliary regulating circuits 18.

[0085] By associating the control signal of the proportional relief valve 172 with the control signals of the first reversing valve 111, the proportional reversing valve 121 and the second reversing valve 181, the state of the proportional relief valve 172 is adjusted according to the states of different valves. Exemplarily, when the active regulating circuit 11 and the driven regulating circuit 12 are used to drive the first multi-stage oil cylinder 13 and the second multi-stage oil cylinder 14, the proportional relief valve 172 is in the first open state, and when the auxiliary regulating circuit 18 is used to drive the auxiliary oil cylinder 19, the proportional relief valve 172 is in the second open state. The flow rate of the proportional relief valve 172 in the first open state and in the second open state may be different. In addition, in the embodiment of the present application, the active regulating circuit 11 and the driven regulating circuit 12 may not be started at the same time as the auxiliary regulating circuit 18, and the load of the first multi-stage oil cylinder 13 and the load of the second multi-stage oil cylinder 14 may be different from the load of the auxiliary oil cylinder 19.

[0086] In this way, the proportional relief valve 172 can meet the different pressure settings of different cylinders, thereby reducing power loss. At the same time, the control component can control the proportional relief valve 172 through a ramp signal to reduce the pressure shock of the hydraulic synchronous drive system during the unloading process. In addition, when the ambient temperature is low and the hydraulic oil temperature is low, resulting in excessive viscosity of the hydraulic oil, the hydraulic synchronous drive system is set to a low pressure state when the control component can be turned on. In the low pressure state, the flow of the proportional relief valve 172 is usually small, thereby avoiding damage to the oil pump 154 ​​in the liquid storage component 15 due to high load operation under unsuitable hydraulic oil viscosity. At the same time, when the proportional relief valve 172 is in an open state, part of the hydraulic oil will flow back to the oil storage tank 151 in the liquid storage component 15 through the proportional relief valve 172. The overflow process will convert the energy output by the oil pump 154 ​​into heat energy, resulting in an increase in the temperature of the hydraulic oil; in this way, the hydraulic oil can be evenly heated by hydraulic overflow heating. Compared with the method of heating the hydraulic oil by a high-power heater 159, the problem of excessive deterioration of the hydraulic oil caused by high-temperature heating of the hydraulic oil can be avoided.

[0087] In addition, the full unloading valve 171 is used to reduce the power loss of the hydraulic synchronous drive system in the standby state. At the same time, the pressure limiting relief valve 173 is used to ensure that the peak pressure of the hydraulic synchronous drive system does not exceed the limit. 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 structure of the liquid storage component 15 in the principle schematic diagram of the hydraulic synchronous drive system shown in the figure, in an optional embodiment, the liquid storage component 15 may also include an oil pump 154, a cooler 155, two filters 156, a temperature sensor 157, a dry respirator 158, a heater 159 and an outlet check valve 15a; the oil pump 154 ​​is installed on the oil outlet pipeline 152, the cooler 155 is installed on the oil return pipeline 153, and the two filters 156 are installed on the oil outlet pipeline 152 and the oil return pipeline 153 respectively; the temperature sensor 157, the dry respirator 158 and the heater 159 are all installed on the oil storage tank 151, and the outlet check valve 15a is located at the oil outlet of the oil pump 154. In addition, the oil storage tank 151 also has an isolation plate 1511 inside, and the extension direction of the isolation plate 1511 intersects with the flow direction of the hydraulic oil in the oil storage tank 151.

[0089] The cleanliness of the hydraulic synchronous drive system can be improved by arranging a filter 156 at the outlet of the oil delivery pump 154 ​​and the oil return line 153. An isolation plate 1511 is arranged inside the oil storage tank 151 to separate the oil storage tank 151 into a clean area and an oil return area. The hydraulic oil in the oil return area needs to pass through an isolation plate of a certain height to enter the clean area, thereby reducing iron filings and bubbles that flow directly to the oil suction port of the oil delivery pump 154.

[0090] The heater 159 can be a low-power heater 159. By arranging the low-power heater 159 and the dry respirator 158 on the oil storage tank 151, the internal temperature of the oil storage tank 151 can be made higher than the environment without affecting the quality of the hydraulic oil, thereby reducing the replacement of the internal gas of the oil storage tank 151 with the ambient gas, and further reducing the generation of condensed water inside the oil tank. The dry respirator 158 can further filter and dry the gas entering the oil tank to reduce the water content of the gas.

[0091] In summary, the embodiment of the present application provides a hydraulic synchronous drive system including an active regulation circuit 11, a passive regulation circuit 12, a first multi-stage oil cylinder 13, a second multi-stage oil cylinder 14, a liquid storage component 15 and a control component. The first multi-stage oil cylinder 13 (also known as the master hydraulic cylinder) is controlled by a reversing valve, and the second multi-stage oil cylinder 14 (also known as the slave hydraulic cylinder) is controlled by a proportional reversing valve 121. The control component can detect the positions of the first multi-stage oil cylinder 13 and the second multi-stage oil cylinder 14 respectively through two rope-type displacement sensors 131, and adjust the control signal of the proportional reversing valve 121 according to the feedback signals of the two rope-type displacement sensors 131, so that the second multi-stage oil cylinder 14 follows the movement of the first multi-stage oil cylinder 13 to achieve synchronous lifting; in this way, it can ensure that the positions or speeds of the first multi-stage oil cylinder 13 and the second multi-stage oil cylinder 14 are consistent, the synchronization accuracy of the hydraulic synchronous drive system can be improved, and the problem of low stability of the hydraulic synchronous drive system in the related art can be solved.

[0092] Please refer to Figure 1 and Figure 8 , Figure 8 It is a structural schematic diagram of an unloading platform provided in an embodiment of the present application. The unloading platform may include: a load-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 load-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, and the first multi-stage cylinder 13 and the second multi-stage cylinder 14 are both connected to the first rotating seat 23; the second end of the load-bearing platform 21 is connected to the second rotating seat 24.

[0093] The unloading platform can be used for unloading cargo from vehicle 31. For example, the unloading platform can be suitable for container trucks that are not equipped with a dump system, have a large tonnage, and require fast unloading. It can improve the unloading efficiency, and the unloading process is safe and smooth, which can significantly improve the safety of vehicle 31, cargo, and personnel.

[0094] In an exemplary embodiment, the unloading platform may also include: a platform tilt angle measuring sensor, and 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 with each other to ensure signal accuracy and platform control safety. The PLC control system controls the opening of the proportional valve reversing valve through multiple detection signals.

[0095] Exemplarily, 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 regulating circuit that currently 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 reversing valve is controlled to operate. The PLC control system detects the platform inclination and the cylinder position deviation, and outputs a corresponding control signal to the proportional reversing valve 121, 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] In addition, the low-power heater 159 in the oil tank 151 can be turned on for a long time to keep the air dry inside the oil tank 151. The hydraulic oil passes through the filter 156 to ensure self-cleaning of the hydraulic oil during use, and reduces bubbles and impurities under the sedimentation effect of the oil tank 151, 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 an exemplary embodiment, the auxiliary cylinder 19 can be used to support the rear wheels of the vehicle 31 to prevent the vehicle 31 from sliding after the lifting platform is raised, thereby improving the safety, efficiency and high-angle performance of the hydraulic synchronous drive system 22.

[0098] It should be noted that in the accompanying drawings, the size of the region may be exaggerated for clarity of illustration. It is also understood that when an element is referred to as being "on" another element, it may be directly on the other element, or there may be an intermediate element. In addition, it is understood that when an element is referred to as being "under" another element, it may be directly under the other element, or there may be more than one intermediate element. In addition, it is also understood that when an element is referred to as being "between" two elements, it may be the only layer between the two elements, or there may be more than one intermediate element. Similar reference numerals throughout the text indicate similar elements.

[0099] In the present application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "plurality" refers to two or more than two, unless otherwise clearly defined.

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

Claims

1. A hydraulic synchronous drive system, characterized in that: include: An active regulating circuit, a passive regulating circuit, a first multi-stage oil cylinder, a second multi-stage oil cylinder, a liquid storage component and a control component; The active regulating circuit comprises a first reversing valve and a first connecting oil circuit, the oil inlet and the oil outlet of the first reversing valve are both connected to the liquid storage assembly, and a 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 regulating circuit comprises a proportional reversing valve and a second connecting oil circuit, the oil inlet and the oil outlet of the proportional reversing valve are both connected to the liquid storage assembly, and a working oil port of the proportional reversing valve is connected to the second multi-stage oil cylinder through the second connecting oil circuit; The first multi-stage oil cylinder and the second multi-stage oil cylinder each have a rope-type displacement sensor, and the rope-type displacement sensor is used to detect the position of the piston rod in the first multi-stage oil cylinder and the second multi-stage oil cylinder; The control component is electrically connected to the rope-type displacement sensor, the first reversing valve and the proportional reversing valve respectively.

2. The hydraulic synchronous drive system according to claim 1, characterized in that: The first multi-stage oil cylinder and the second multi-stage oil cylinder both include: an outer cylinder barrel, a multi-stage piston, a first end cover portion and the rope-type 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 cover is fixedly connected to one end of the outer cylinder, and the first end cover has a receiving cavity, and the receiving cavity has a first opening on a side facing the outer cylinder; The rope-type displacement sensor has a pull rope, at least a portion of which is located in the accommodating portion, 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-type displacement sensor comprises a driving motor, a rotating shaft, a reel, the pull rope and an encoder, the first end cover portion has a first mounting through hole, and the first mounting through hole is communicated with the accommodating cavity; The driving 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 cover portion; The rotating shaft is inserted into the first mounting through hole, and two ends of the rotating shaft are respectively connected to the driving motor and the reel; At least a portion of the pull rope is wound on the drum; The encoder is electrically connected to the drive motor and the control component respectively.

4. The hydraulic synchronous drive system according to claim 3, characterized in that: The rope-type displacement sensor also includes a drum support and a pressure ring structure; The reel support is fixedly mounted on the inner wall of the accommodating cavity of the first end cover portion; The reel is mounted on the reel support and is rotatably connected to the reel support. The surface of the reel has a plurality of annular guide grooves, and the plurality of annular guide grooves are arranged along the axial direction of the reel. The pressure ring structure is located at one side of the reel and is fixedly connected to the reel support. The pressure ring structure is used to guide the pull rope to enter or leave 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 oil cylinder and the second multi-stage oil cylinder also include: a first buffer pad and a second buffer pad; The first buffer pad is located between the end of the piston rod close to the first end cover and the bottom of the first piston cylinder, and the first buffer pad is fixedly connected to the end of the piston rod close to the first end cover or the bottom of the first piston cylinder; The second buffer pad is located between the end of the first piston cylinder close to the first end cover and the bottom of the outer cylinder, and the second buffer pad is fixedly connected to the end of the first piston cylinder close to the first end cover or the bottom of the outer cylinder.

6. The hydraulic synchronous drive system according to any one of claims 1 to 5, characterized in that: The active regulation circuit further includes: a one-way oil inlet speed regulating valve, a one-way oil return throttle valve and a first balancing valve, wherein the one-way oil inlet speed regulating valve and the one-way oil return throttle valve are arranged in series on the first connecting oil circuit, the two working oil ports of the first balancing valve are both connected to the first connecting oil circuit, and the control oil port of the first balancing valve is connected to the other working oil port of the first reversing valve; The driven regulating circuit also includes: a second balancing valve, both working oil ports of the second balancing valve are connected to the second connecting oil circuit, and the control oil port of the second balancing valve is connected to another working oil port of the proportional reversing valve.

7. The hydraulic synchronous drive system according to claim 6, characterized in that: The hydraulic synchronous drive system further comprises a first throttle valve, a second throttle valve and a ball valve, and the liquid storage assembly comprises an oil storage tank, an oil outlet pipeline and an oil return pipeline; The first throttle valve is respectively connected to the first multi-stage oil cylinder and the first end of the ball valve; The second throttle valve is communicated with the second multi-stage oil cylinder and the first end of the ball valve respectively; The second end of the ball valve is in communication with the oil return pipeline; The oil return pipeline and the oil outlet pipeline are both communicated with 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 regulating circuit and an auxiliary oil cylinder; The loading circuit includes a full unloading valve, a proportional relief valve and a pressure limiting relief valve, and the full unloading valve, the proportional relief valve and the pressure limiting relief valve are respectively connected to the oil outlet pipeline and the oil return pipeline; 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, the oil outlet of the second reversing valve is connected to the oil return pipeline, and 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 transfer pump, a cooler, two filters, a temperature sensor, a dry respirator and a heater; The oil delivery 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 dry respirator and the heater are all installed on the oil storage tank, and the oil storage tank is further provided with an isolation plate inside, and the extension direction of the isolation plate intersects with the flow direction of the hydraulic oil in the oil storage tank.

10. A cargo unloading platform, characterized in that: include: A bearing platform, 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 carrying platform is connected to the first multi-stage oil cylinder and the second multi-stage oil cylinder in the hydraulic synchronous drive system, and the first multi-stage oil cylinder and the second multi-stage oil cylinder are both connected to the first rotating seat; The second end of the carrying platform is connected to the second rotating seat.

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