Single cylinder latch hydraulic control system, telescopic arm and crane

Abstract

The present invention provides a single-cylinder latch hydraulic control system, a telescopic arm, and a crane. The above-mentioned single-cylinder latch hydraulic control system includes: a telescopic oil cylinder; the first end of the core tube is arranged in the inner cavity of the piston rod of the telescopic oil cylinder, the second end of the core tube is connected to the bottom of the cylinder barrel of the telescopic oil cylinder, and the core tube is in communication with the inner cavity; a first control oil circuit is connected to the inner cavity, and an electric proportional relief valve is provided on the first control oil circuit; a second control oil circuit is connected to the core tube, and the second control oil circuit is selectively connected to the cylinder pin oil cylinder or the arm pin oil cylinder, and a pressure sensor is provided on the second control oil circuit; the controller adjusts the input current of the electric proportional relief valve according to the real-time pressure data in the core tube detected by the pressure sensor to keep the pressure in the core tube constant; the first control oil circuit, the core tube, and the second control oil circuit constitute the oil supply circuit and the oil return circuit of the cylinder pin oil cylinder and the arm pin oil cylinder. The above-mentioned technical solution realizes the constant pressure in the core tube and enhances the stability and safety of the system.

Description

Technical Field

[0001] The present invention relates to the field of hydraulic technology, and in particular to a single-cylinder latch hydraulic control system, a telescopic arm and a crane. Background Art

[0002] Currently, cranes with more than five boom sections commonly use a single-cylinder latch-type telescopic boom. The piston rod of the telescopic cylinder on this type of telescopic boom is connected to the base boom. The telescopic boom's movement is achieved through the interaction of two cylinder pins on the cylinder head and the arm pins between adjacent telescopic boom sections. In existing solutions, the telescopic cylinder's extension and retraction are controlled by the telescopic boom control circuit, while the arm and cylinder pins are retracted using a separate control circuit. Oil is supplied to the arm and cylinder pin cylinders via a core tube inside the telescopic cylinder. In existing technologies, the pressure of the single-cylinder latch hydraulic control system is manually set, making it impossible to adjust the pressure of the single-cylinder latch hydraulic control system based on the real-time pressure of the core tube. As the telescopic boom retracts and retracts, the volume of the inner cavity connected to the core tube changes, causing the pressure inside the core tube to increase or decrease. When the telescopic boom is extended, the pressure inside the core tube decreases, increasing the risk of the cylinder or arm pins resetting. When the telescopic boom is retracted, the pressure inside the core tube increases, which can easily damage the core tube. Summary of the Invention

[0003] The present invention provides a single-cylinder latch hydraulic control system, a telescopic arm and a crane, which are used to solve the defect in the prior art that the internal pressure of the single-cylinder latch hydraulic control system cannot be adjusted in real time when the telescopic oil cylinder moves.

[0004] The present invention provides a single-cylinder latch hydraulic control system, comprising: a telescopic oil cylinder; a core tube, a first end of the core tube being arranged in the inner cavity of the piston rod of the telescopic oil cylinder, a second end of the core tube being connected to the bottom of the cylinder barrel of the telescopic oil cylinder, and the core tube being in communication with the inner cavity; a first control oil circuit being connected to the inner cavity, an electric proportional relief valve being provided on the first control oil circuit; a second control oil circuit being connected to the core tube, the second control oil circuit being selectively connected to a cylinder pin oil cylinder or an arm pin oil cylinder, a pressure sensor being provided on the second control oil circuit; a controller adjusting an input current of the electric proportional relief valve according to real-time pressure data in the core tube detected by the pressure sensor, so as to keep the pressure in the core tube constant; wherein the first control oil circuit, the core tube and the second control oil circuit constitute an oil supply circuit and an oil return circuit of the cylinder pin oil cylinder and the arm pin oil cylinder.

[0005] According to a single-cylinder latch hydraulic control system provided by the present invention, the first control oil circuit includes: a first oil circuit, an oil source is provided on the first oil circuit; a second oil circuit, the second oil circuit is an oil return circuit; a first reversing valve, the first reversing valve has at least two working positions, when the first reversing valve is in different working positions, the inner cavity is connected to the first oil circuit or the second oil circuit through the first reversing valve; wherein, the two ends of the electric proportional relief valve are respectively connected to the first oil circuit and the second oil circuit.

[0006] According to a single-cylinder latch hydraulic control system provided by the present invention, the oil source includes: an oil tank; a pump, the oil inlet of the pump is connected to the oil tank, and the oil outlet of the pump is connected to the first reversing valve and the electric proportional relief valve.

[0007] According to a single-cylinder latch hydraulic control system provided by the present invention, the second oil circuit includes: a first one-way valve, the oil inlet of the first one-way valve is connected to the first reversing valve, and the oil outlet of the first one-way valve is connected to the oil tank.

[0008] According to a single-cylinder latch hydraulic control system provided by the present invention, the first control oil circuit further includes: a safety valve, and both ends of the safety valve are connected to the second oil circuit and the inner cavity respectively.

[0009] According to a single-cylinder latch hydraulic control system provided by the present invention, the second control oil circuit includes: a third oil circuit, a first end of the third oil circuit is connected to the core tube, a second end of the third oil circuit is selectively connected to the cylinder pin cylinder or the arm pin cylinder, and the pressure sensor is provided on the third oil circuit; a fourth oil circuit, an oil inlet of the fourth oil circuit is connected to the cylinder pin cylinder or the arm pin cylinder, and an oil outlet of the fourth oil circuit is connected to the core tube.

[0010] According to a single-cylinder latch hydraulic control system provided by the present invention, the third oil circuit includes: a second reversing valve, the second reversing valve has at least two working positions, and when the second reversing valve is in different working positions, the second reversing valve is connected to the cylinder pin cylinder or the arm pin cylinder.

[0011] According to a single-cylinder latch hydraulic control system provided by the present invention, the fourth oil circuit includes: a second one-way valve, the oil inlet of the second one-way valve is connected to the cylinder pin cylinder or the arm pin cylinder, and the oil outlet of the second one-way valve is connected to the core tube; and a damper, the damper is arranged at the oil inlet of the second one-way valve.

[0012] The present invention also provides a telescopic arm, comprising the single-cylinder latch hydraulic control system as described above.

[0013] The present invention also provides a crane comprising the telescopic arm as described above.

[0014] The single-cylinder latch hydraulic control system provided by the present invention, by providing a pressure sensor, an electric proportional relief valve, and a controller, can adjust the input current of the electric proportional relief valve in real time, thereby maintaining a constant pressure within the core tube, thereby preventing the increase or decrease in the internal pressure of the core tube from affecting the core tube or the cylinder pin cylinder and arm pin cylinder. The single-cylinder latch hydraulic control system provided by the present invention achieves pressure compensation under the action of the telescopic cylinder, as well as pressure compensation when the telescopic arm is at different temperatures and when the core tube is at different degrees of wear, thereby enhancing the stability and safety of the single-cylinder latch hydraulic control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 This is a schematic diagram of the single-cylinder latch hydraulic control system provided by the present invention;

[0017] Figure 2 This is a control logic diagram of the single-cylinder latch hydraulic control system provided by the present invention;

[0018] Reference numerals:

[0019] 10: First oil circuit; 11: Oil tank; 12: Pump; 20: Second oil circuit; 21: First one-way valve; 30: First reversing valve; 40: Electric proportional relief valve; 50: Safety valve; 60: Third oil circuit; 61: Pressure sensor; 62: Second reversing valve; 70: Fourth oil circuit; 71: Second one-way valve; 72: Damping; 100: Telescopic cylinder; 101: Cylinder pin cylinder; 102: Arm pin cylinder; 103: Piston rod; 104: Core tube; 105: First oil port; 106: Second oil port; 200: Controller. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0021] The features of the terms "first" and "second" in the description and claims of the present invention may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0022] The following combination Figure 1 and Figure 2 The invention describes a single-cylinder latch hydraulic control system, a telescopic arm and a crane.

[0023] like Figure 1 and Figure 2 As shown, in one embodiment of the present invention, a single-cylinder latch hydraulic control system includes: a telescopic cylinder 100, a core tube 104, a first control oil circuit, a second control oil circuit, an electric proportional relief valve 40, a pressure sensor 61, and a controller 200. A cylinder pin cylinder 101 is disposed on the cylinder head of the telescopic cylinder 100. Movement of the cylinder head of the telescopic cylinder 100 can drive the cylinder pin cylinder 101 to move together. The piston rod 103 of the telescopic cylinder 100 has an inner cavity. The first end of the core tube 104 is disposed within the inner cavity of the telescopic cylinder 100. The second end of the core tube 104 is connected to the bottom of the cylinder barrel of the telescopic cylinder 100, and the core tube 104 is in communication with the inner cavity. The first control oil circuit is connected to the inner cavity, and an electric proportional relief valve 40 is provided on the first control oil circuit. The second control oil circuit is connected to the core tube 104, and the second control oil circuit is selectively connected to the cylinder pin cylinder 101 or the arm pin cylinder 102. The second control oil circuit is provided with a pressure sensor 61, and the pressure sensor 61 is used to detect real-time pressure data in the core tube 104. The first control oil circuit, the core tube 104, and the second control oil circuit constitute the oil supply circuit and the oil return circuit of the cylinder pin cylinder 101 and the arm pin cylinder 102. The controller 200 is used to adjust the input current of the electric proportional relief valve 40 according to the real-time pressure data detected by the pressure sensor 61 to adjust the pressure in the core tube 104, thereby keeping the pressure in the core tube 104 constant.

[0024] Specifically, a first oil port 105 and a second oil port 106 are provided on the piston rod 103 of the telescopic cylinder 100. The first oil port 105 is used to supply oil to the rod chamber of the telescopic cylinder 100, and the second oil port 106 is used to supply oil to the rodless chamber of the telescopic cylinder 100. The piston rod 103 is provided with an inner cavity, and the inner cavity is connected with the core tube 104. The hydraulic oil enters the inner cavity of the piston rod 103 through the first control oil circuit, and then enters the rod chamber of the cylinder pin cylinder 101 or the rod chamber of the arm pin cylinder 102 through the second control oil circuit from the core tube 104, thereby realizing the contraction of the piston rod of the cylinder pin cylinder 101 or the arm pin cylinder 102, thereby realizing the unlocking of the cylinder pin cylinder 101 and the arm section, or the unlocking of the arm pin cylinder 102 and the arm section.

[0025] When the cylinder pin cylinder 101 is locked with the boom section, the hydraulic oil in the cylinder pin cylinder 101 passes through the second control oil circuit, the core tube 104 and the first control oil circuit into the oil tank 11. At this time, the piston rod of the cylinder pin cylinder 101 extends, the cylinder pin cylinder 101 is connected to the pin hole on the crane boom section, the telescopic cylinder 100 extends to drive the boom section to move, and when the boom section moves into place, the arm pin cylinder 102 locks the two adjacent boom sections. At this time, the rod chamber of the arm pin cylinder 102 returns oil, and the hydraulic oil passes through the second control oil circuit, the core tube 104 and the first control oil circuit into the oil tank 11. At this time, the cylinder pin cylinder 101 is unlocked from the boom section, the first control oil circuit supplies oil to the cylinder pin cylinder 101, and the hydraulic oil passes through the first control oil circuit, the core tube 104 and the second control oil circuit into the rod chamber of the cylinder pin cylinder 101. The piston rod of the cylinder pin cylinder 101 contracts, and the lock with the boom section is released. Then, the telescopic cylinder 100 is retracted and the next boom section is sent out using the above method.

[0026] During the extension or contraction of the telescopic cylinder 100, the pressure sensor 61 sends the real-time pressure data detected in the core tube 104 to the controller 200. The controller 200 can calculate the initial calibration current of the electric proportional relief valve 40 based on the characteristic fitting curve of the electric proportional relief valve 40. The controller 200 compares the real-time pressure data with the target pressure data to obtain the pressure difference between the real-time pressure data and the target pressure data, and uses the pressure difference as a correction value for the calibration current, thereby adjusting the input current of the electric proportional relief valve 40, and thereby adjusting the pressure inside the core tube 104 to increase or decrease, so that the pressure inside the core tube 104 is always constant. For example, when the telescopic cylinder 100 extends, the pressure inside the core tube 104 decreases. At this time, the input current of the electric proportional relief valve 40 can be adjusted to increase the pressure inside the core tube 104, so that the current pressure inside the core tube 104 is the same as the initial pressure. Correspondingly, when the telescopic cylinder 100 contracts, the pressure inside the core tube 104 increases. At this time, the input current of the electric proportional relief valve 40 can be adjusted to decrease the pressure inside the core tube 104, so that the current pressure inside the core tube 104 is the same as the initial pressure. Furthermore, when the ambient temperature of the single-cylinder latch hydraulic control system changes, or when the core tube 104 experiences varying degrees of wear, or when other factors cause the pressure inside the core tube 104 to change, the controller 200 can adjust the input current of the electric proportional relief valve 40 based on the real-time pressure data inside the core tube 104 detected by the pressure sensor 61, thereby adjusting the current pressure inside the core tube 104 so that the current pressure is always the same as the initial pressure, thereby maintaining a constant pressure inside the core tube 104.

[0027] The single-cylinder latch hydraulic control system provided by the embodiment of the present invention can adjust the input current of the electric proportional overflow valve in real time by providing a pressure sensor, an electric proportional overflow valve and a controller, thereby keeping the pressure in the core tube constant, thereby preventing the increase or decrease in the pressure inside the core tube from affecting the core tube or the cylinder pin cylinder and the arm pin cylinder. The single-cylinder latch hydraulic control system provided by the embodiment of the present invention realizes pressure compensation under the action of the telescopic cylinder, as well as pressure compensation when the telescopic arm is at different temperatures and when the core tube is at different degrees of wear, thereby enhancing the stability and safety of the single-cylinder latch hydraulic control system.

[0028] like Figure 1 As shown, in one embodiment of the present invention, the first control oil circuit includes: a first oil circuit 10, a second oil circuit 20, and a first reversing valve 30. The first oil circuit 10 is provided with an oil source, the second oil circuit 20 is an oil return circuit, and the first reversing valve 30 has at least two working positions. When the first reversing valve 30 is in different working positions, the inner cavity is connected to the first oil circuit 10 or the second oil circuit 20 through the first reversing valve 30. The two ends of the electric proportional relief valve 40 are connected to the first oil circuit 10 and the second oil circuit 20 respectively.

[0029] Specifically, when the telescopic cylinder 100 is locked with the boom section, the rod chamber of the pin cylinder 101 returns oil, and the hydraulic oil flows through the second control oil circuit, the core tube 104, the first reversing valve 30, and the second oil circuit 20 into the oil tank 11. The telescopic cylinder 100 extends, driving the boom section to move. At this time, the pressure inside the core tube 104 decreases. The pressure sensor 61 transmits the detected real-time pressure data to the controller 200. The controller 200 adjusts the input current of the electric proportional relief valve 40 based on the pressure difference between the real-time pressure data and the target pressure data, and further adjusts the input pressure of the first reversing valve 30, increasing the pressure inside the core tube 104 and thus maintaining the current pressure inside the core tube 104 at the same level as the initial pressure. For example, if the pressure inside the core tube 104 decreases from 5 MPa to 3 MPa during the extension process of the telescopic cylinder 100, the pressure inside the core tube 104 can be maintained at 5 MPa by adjusting the input current of the electric proportional relief valve 40.

[0030] When the telescopic cylinder 100 drives the arm section to move, the hydraulic oil passes through the first oil circuit 10, the first reversing valve 30, the core tube 104 and the second control oil circuit into the rod chamber of the arm pin cylinder 102, and the arm pin cylinder 102 is released from the arm section; after the telescopic cylinder 100 drives the arm section to move into place, the rod chamber of the arm pin cylinder 102 returns oil, and the arm pin cylinder 102 locks the two adjacent arm sections, and the hydraulic oil passes through the first oil circuit 10, the first reversing valve 30, the core tube 104 and the second control oil circuit into the rod chamber of the cylinder pin cylinder 101, and the cylinder pin cylinder 101 is released from the arm section. When the telescopic cylinder 100 contracts, the pressure inside the core tube 104 increases. At this time, the pressure sensor 61 sends the detected real-time pressure data to the controller 200. The controller 200 adjusts the input current of the electric proportional relief valve 40 according to the pressure difference between the real-time pressure data and the target pressure data, and then adjusts the input pressure of the first reversing valve 30 to reduce the pressure in the core tube 104, so that the current pressure in the core tube 104 is the same as the initial pressure.

[0031] Furthermore, in this embodiment, the first reversing valve 30 is an electromagnetic reversing valve, and the first reversing valve 30 has two working positions. When it is located in the right working position, the second oil circuit 20 is connected with the core tube 104, so that the oil returns to the rod chamber of the cylinder pin cylinder 101 or the arm pin cylinder 102; when it is located on the left working position, the first oil circuit 10 is connected with the core tube 104, so that the oil enters the rod chamber of the cylinder pin cylinder 101 or the arm pin cylinder 102.

[0032] Furthermore, if Figure 1 As shown, in this embodiment, the oil source includes: an oil tank 11 and a pump 12 , the oil inlet of the pump 12 is connected to the oil tank 11 , and the oil outlet of the pump 12 is connected to the first reversing valve 30 and the electric proportional relief valve 40 .

[0033] Furthermore, the second oil circuit 20 includes a first one-way valve 21, the oil inlet of the first one-way valve 21 is connected to the first reversing valve 30, and the oil outlet of the first one-way valve 21 is connected to the oil tank 11. The first one-way valve 21 can prevent the hydraulic oil in the oil tank 11 from entering the core tube 104.

[0034] Furthermore, the first control oil circuit also includes a safety valve 50, the two ends of which are respectively connected to the second oil circuit 20 and the inner cavity of the telescopic cylinder 100. The safety valve 50 is used to overflow when the valve core of the first reversing valve 30 is stuck or blocked to protect the core tube 104.

[0035] like Figure 1As shown, in one embodiment of the present invention, the second control oil circuit includes: a third oil circuit 60 and a fourth oil circuit 70. The first end of the third oil circuit 60 is connected to the core tube 104, and the second end of the third oil circuit 60 selectively communicates with the cylinder pin cylinder 101 or the arm pin cylinder 102. The third oil circuit 60 is provided with a pressure sensor 61. The oil inlet of the fourth oil circuit 70 is connected to the cylinder pin cylinder 101 or the arm pin cylinder 102, and the oil outlet of the fourth oil circuit 70 is connected to the core tube 104.

[0036] Specifically, when the cylinder pin cylinder 101 is locked with the arm joint, the hydraulic oil in the rod chamber of the cylinder pin cylinder 101 enters the oil tank 11 through the fourth oil path 70 , the core tube 104 , the first reversing valve 30 and the second oil path 20 . When the telescopic cylinder 100 drives the arm section to move, the hydraulic oil passes through the first oil circuit 10, the first reversing valve 30, the core tube 104 and the third oil circuit 60 into the rod chamber of the arm pin cylinder 102, and the arm pin cylinder 102 is released from the arm section; after the telescopic cylinder 100 drives the arm section to move into place, the rod chamber of the arm pin cylinder 102 returns oil, and the hydraulic oil in the rod chamber of the arm pin cylinder 102 passes through the fourth oil circuit 70, the core tube 104, the first reversing valve 30 and the second oil circuit 20 into the oil tank 11, and the arm pin cylinder 102 locks the two adjacent arm sections, and the hydraulic oil passes through the first oil circuit 10, the first reversing valve 30, the core tube 104 and the third oil circuit 60 into the rod chamber of the cylinder pin cylinder 101, and the cylinder pin cylinder 101 is released from the arm section, and the telescopic cylinder 100 contracts. During the extension or contraction of the telescopic cylinder 100 , the pressure sensor 61 always detects the real-time pressure data in the core tube 104 .

[0037] like Figure 1 As shown, the third oil circuit 60 includes a second reversing valve 62, which is used to control the communication between the core tube 104 and the cylinder pin cylinder 101 or the arm pin cylinder 102. The second reversing valve 62 has at least two working positions. When the second reversing valve 62 is in different working positions, the second reversing valve 62 is connected to the cylinder pin cylinder 101 or the arm pin cylinder 102 respectively.

[0038] Specifically, in this embodiment, the second reversing valve 62 is an electromagnetic reversing valve, which has two working positions. When it is located at the right working position, the core tube 104 is connected with the arm pin cylinder 102, and oil enters the rod chamber of the arm pin cylinder 102; when it is located at the left working position, the core tube 104 is connected with the cylinder pin cylinder 101, and oil enters the rod chamber of the cylinder pin cylinder 101.

[0039] It is understood that the second reversing valve 62 may also be a three-position, three-way solenoid reversing valve. When it is in the right working position, the core tube 104 is connected to the arm pin oil cylinder 102; when it is in the left working position, the core tube 104 is connected to the cylinder pin oil cylinder 101; when it is in the middle working position, the core tube 104 is not connected to either the cylinder pin oil cylinder 101 or the arm pin oil cylinder 102. When the second reversing valve 62 is a three-position, three-way solenoid reversing valve, the oil inlet of the second reversing valve 62 is connected to one oil outlet, and the other oil outlet is not connected.

[0040] like Figure 1 As shown, in one embodiment of the present invention, the fourth oil circuit 70 includes: a second one-way valve 71 and a damper 72, the oil inlet of the second one-way valve 71 is connected to the cylinder pin cylinder 101 or the arm pin cylinder 102, the oil outlet of the second one-way valve 71 is connected to the core tube 104, and the damper 72 is arranged at the oil inlet of the second one-way valve 71.

[0041] Specifically, when the rod chamber of the cylinder pin cylinder 101 or the arm pin cylinder 102 returns oil, the hydraulic oil enters the core tube 104 through the damper 72 and the second one-way valve 71, and then enters the oil tank 11 through the first reversing valve 30 and the first one-way valve 21.

[0042] An embodiment of the present invention further provides a telescopic arm, including a single-cylinder latch hydraulic control system.

[0043] Specifically, the telescopic boom includes multiple arm sections that are sleeved together. The piston rod 103 of the telescopic cylinder 100 of the single-cylinder latch hydraulic control system is connected to the basic arm section. The cylinder pin cylinder 101 is used to lock with the pin hole on each arm section. When the cylinder head of the telescopic cylinder 100 moves, the telescopic cylinder 100 drives the arm section to extend. When the arm section is fully extended, the arm pin cylinder 102 of the single-cylinder latch hydraulic control system locks the two adjacent arm sections with the arm pin. Then, the cylinder pin cylinder 101 is unlocked from the arm section, the telescopic cylinder 100 retracts, and then the cylinder pin cylinder 101 is locked with the lower arm section. The telescopic cylinder 100 extends, driving the lower arm section to extend. This process is repeated until all arm sections are extended in sequence.

[0044] The telescopic arm provided in an embodiment of the present invention, by setting up a single-cylinder latch hydraulic control system, can adjust the pressure in the core tube in real time during the extension or contraction of the telescopic arm, so that the current pressure in the core tube is always the same as the initial pressure, thereby avoiding the increase or decrease in the pressure in the core tube affecting the core tube or the telescopic arm.

[0045] An embodiment of the present invention further provides a crane, comprising a telescopic arm.

[0046] The crane provided in an embodiment of the present invention is equipped with a telescopic arm. During the extension or contraction of the telescopic arm, the pressure in the core tube can be adjusted in real time so that the current pressure in the core tube is always the same as the initial pressure, thereby avoiding the influence of the increase or decrease of the pressure in the core tube on the core tube or the telescopic arm.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A single-cylinder latch hydraulic control system, characterized in that: include: Telescopic cylinder; A core tube, wherein a first end of the core tube is disposed in an inner cavity of the piston rod of the telescopic oil cylinder, a second end of the core tube is connected to the bottom of the cylinder barrel of the telescopic oil cylinder, and the core tube is in communication with the inner cavity; a first control oil circuit connected to the inner cavity, wherein an electric proportional relief valve is provided on the first control oil circuit; a second control oil circuit connected to the core tube, the second control oil circuit being selectively connected to the cylinder pin oil cylinder or the arm pin oil cylinder, and a pressure sensor being provided on the second control oil circuit; a controller, adjusting an input current of the electric proportional relief valve according to real-time pressure data in the core tube detected by the pressure sensor, so as to keep the pressure in the core tube constant; Wherein, the first control oil circuit, the core tube and the second control oil circuit constitute the oil supply circuit and the oil return circuit of the cylinder pin cylinder and the arm pin cylinder; The second control oil circuit includes: a third oil circuit, wherein a first end of the third oil circuit is connected to the core tube, a second end of the third oil circuit is selectively connected to the cylinder pin oil cylinder or the arm pin oil cylinder, and the pressure sensor is provided on the third oil circuit; a fourth oil circuit, wherein an oil inlet of the fourth oil circuit is connected to the cylinder pin oil cylinder or the arm pin oil cylinder, and an oil outlet of the fourth oil circuit is connected to the core tube; The fourth oil circuit includes: a second one-way valve, wherein the oil inlet of the second one-way valve is connected to the cylinder pin oil cylinder or the arm pin oil cylinder, and the oil outlet of the second one-way valve is connected to the core tube; Damping, the damping is provided at the oil inlet of the second one-way valve; During the extension or contraction of the telescopic cylinder, the pressure sensor sends the detected real-time pressure data in the core tube to the controller. The controller calculates the initial calibration current of the electric proportional relief valve based on the characteristic fitting curve of the electric proportional relief valve. The controller is used to compare the real-time pressure data with the target pressure data to obtain the pressure difference between the real-time pressure data and the target pressure data, and use the pressure difference as a correction value for the calibration current, thereby adjusting the input current of the electric proportional relief valve to increase or decrease the pressure in the core tube, thereby keeping the pressure in the core tube constant.

2. The single-cylinder latch hydraulic control system according to claim 1, characterized in that: The first control oil circuit includes: a first oil circuit, wherein an oil source is provided on the first oil circuit; a second oil circuit, wherein the second oil circuit is an oil return circuit; a first reversing valve, wherein the first reversing valve has at least two working positions, and when the first reversing valve is located at different working positions, the inner cavity is connected to the first oil circuit or the second oil circuit through the first reversing valve; Wherein, both ends of the electric proportional relief valve are connected to the first oil circuit and the second oil circuit respectively.

3. The single-cylinder latch hydraulic control system according to claim 2, characterized in that: The oil source includes: tank; A pump, wherein the oil inlet of the pump is connected to the oil tank, and the oil outlet of the pump is connected to the first reversing valve and the electric proportional relief valve.

4. The single-cylinder latch hydraulic control system according to claim 2, characterized in that: The second oil circuit includes: A first one-way valve, wherein the oil inlet of the first one-way valve is connected to the first reversing valve, and the oil outlet of the first one-way valve is connected to the oil tank.

5. The single-cylinder latch hydraulic control system according to claim 2, characterized in that: The first control oil circuit further includes: A safety valve, wherein both ends of the safety valve are connected to the second oil circuit and the inner cavity respectively.

6. The single-cylinder latch hydraulic control system according to claim 1, characterized in that: The third oil circuit includes: The second reversing valve has at least two working positions. When the second reversing valve is located at different working positions, the second reversing valve is connected to the cylinder pin cylinder or the arm pin cylinder.

7. A telescopic arm, characterized in that: The invention comprises the single-cylinder latch hydraulic control system according to any one of claims 1 to 6.

8. A crane, characterized in that: Including the telescopic arm according to claim 7.

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