A control device for the hydraulic jacking system of a tower crane

Abstract

The present invention discloses a control device for a tower crane hydraulic jacking system, comprising a hydraulic oil tank; a hydraulic pump connected to the hydraulic oil tank, a liquid level temperature sensor, a radiator, an integrated valve, a jacking cylinder, and a controller. The hydraulic pump delivers hydraulic oil to the jacking cylinder via the integrated valve. The liquid level temperature sensor is used to monitor the temperature of the hydraulic oil in the hydraulic oil tank and transmit the monitored real-time temperature to the controller via an electrical signal. The integrated valve includes a three-position, four-way reversing valve for delivering hydraulic oil, a reversing valve for starting and stopping the hydraulic jacking system, a throttle valve for buffering the reciprocating stroke of the jacking cylinder, a back pressure valve for improving system performance, and a safety valve for overload protection of the system. The present invention utilizes radiator temperature control, together with the throttle valve and buffer valve, to mitigate hydraulic shock, thereby ensuring a safe and reliable jacking process. Heat dissipation and temperature reduction in the hydraulic jacking system extend the service life of the hydraulic oil and improve the safety factor of the tower crane jacking system.

Description

Technical Field

[0001] The invention relates to a control device for a hydraulic jacking system of a tower crane, belonging to the technical field of hydraulic jacking systems of tower cranes. Background Art

[0002] In existing tower crane designs, self-erecting tower cranes typically utilize hydraulic systems for tower lifting and sectioning. This system utilizes the pressure energy of hydraulic oil to transmit power, converting mechanical energy into pressure energy in the power element and then back into mechanical energy in the actuator. This conversion process generates pressure loss, which is dissipated into the system as heat, causing the hydraulic oil to heat up. Especially during continuous lifting, due to the long operation of the hydraulic system, the hydraulic oil heats up significantly, reducing its viscosity and increasing wear on hydraulic components. Increased oil temperature also increases internal leakage in the hydraulic system, making various hydraulic system performance unstable and reducing hydraulic system accuracy. Increased oil temperature causes the spool and valve body of the hydraulic system's control valve to expand due to heat, reducing the clearance, affecting spool movement, increasing wear, and even causing it to become stuck, impacting hydraulic system operation. Increased oil temperature also accelerates the oxidation rate of the hydraulic oil, making it prone to deterioration and shortening its service life.

[0003] When the existing hydraulic system stops or reverses the cylinder movement, there is no buffer device to alleviate the hydraulic impact force such as the hydraulic system inertia generated during operation. This causes increased wear of hydraulic components, shaking of the tower crane upper part, and deviation of the tilt angle of the tower crane's lifting beam.

[0004] In summary, the increase in hydraulic oil temperature in the existing tower crane hydraulic system, as well as the immediate stop and reverse operation of the system without safety protection, have a very adverse impact on the normal operation of the jacking mechanism.

[0005] After prolonged operation, hydraulic systems experience wear of hydraulic components and contamination of the hydraulic oil by external environmental pollutants. Impurities in the hydraulic oil exacerbate wear on friction surfaces, causing a temperature rise. Existing hydraulic systems do not mitigate hydraulic shock forces when the cylinder stops or reverses. This can lead to the following technical drawbacks: 1. System leakage. Excessive hydraulic oil temperature rise directly reduces the viscosity of the hydraulic oil and deforms rubber seals. Due to the temperature-viscosity of hydraulic oil, seal deformation can cause loss of sealing performance, leading to system leakage. 2. Hydraulic system blockage. System heat accelerates hydraulic oil oxidation, allowing dissolved air to escape, resulting in cavitation and deteriorating the hydraulic oil, reducing lubrication properties. Furthermore, oxidative emulsification and deterioration of the hydraulic oil can form colloidal particles, leading to system blockage and reduced performance. 3. Piston rod fracture in the lifting cylinder. Stress concentration in tower crane lifting cylinders is at the junction between the piston and the piston sleeve (where the piston diameter decreases from large to small). During sudden stops and reverses, the hydraulic shock force combined with the weight of the lifting load can easily cause the piston rod to break. Summary of the Invention

[0006] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a solution to the problem of excessively high oil temperature in a tower crane hydraulic jacking system and a solution to the pressure shock problem of the hydraulic oil in a tower crane hydraulic jacking system.

[0007] The present invention is realized by the following technical solution: a control device for a hydraulic jacking system of a tower crane, wherein the hydraulic jacking system of the tower crane comprises a hydraulic oil tank and an oil pipe for conveying hydraulic oil; the oil pipe comprises an oil inlet pipe and an oil outlet pipe; and the control device comprises a hydraulic pump connected to the hydraulic oil tank, a liquid level temperature sensor, a radiator, an integrated valve, a jacking oil cylinder, and a controller;

[0008] The hydraulic pump delivers hydraulic oil to the jacking cylinder through the integrated valve;

[0009] The liquid level temperature sensor is used to monitor the temperature of the hydraulic oil in the hydraulic oil tank and transmit the monitored real-time temperature to the controller via an electrical signal;

[0010] The integrated valve includes a three-position four-way reversing valve for controlling the reversing movement of the jacking oil cylinder piston, a reversing valve for controlling the start and stop of the hydraulic jacking system, a throttle valve for realizing a buffering function during the reciprocating stroke of the jacking oil cylinder, a back pressure valve for improving the performance of the tower crane hydraulic jacking system and preventing high-pressure oil from flowing into the hydraulic oil tank, a safety valve for overload protection of the tower crane hydraulic jacking system, and a low-pressure relief valve that opens when the tower crane hydraulic jacking system needs to be unloaded;

[0011] The radiator is used to cool the hydraulic oil in the oil circuit;

[0012] The controller sets the maximum hydraulic oil temperature and performs a logical judgment with the real-time temperature electrical signal received from the liquid level temperature sensor;

[0013] The lifting oil cylinder includes a hydraulic oil cylinder and a two-way hydraulic lock installed on the inlet and outlet oil pipes of the hydraulic oil cylinder to prevent the lifting oil cylinder from falling down due to the effect of the load gravity;

[0014] When the real-time temperature of the liquid level temperature sensor is lower than the maximum hydraulic oil temperature set in the controller, the lifting cylinder works normally;

[0015] When the real-time temperature of the liquid level temperature sensor is greater than or equal to the maximum hydraulic oil temperature set in the controller, the controller starts the radiator and sends signals to the reversing valve and throttle valve at the same time. The reversing valve introduces the hydraulic oil in the oil circuit into the oil circuit branch pipe through the radiator and flows into the hydraulic oil tank. The throttle valve limits the flow of hydraulic oil into the jacking cylinder, prolonging the reversing movement time of the jacking cylinder piston rod to reduce the hydraulic shock generated when the hydraulic cylinder piston is reversing, thereby achieving the purpose of safety and stability.

[0016] The lifting cylinder works normally until the real-time temperature monitored by the liquid level temperature sensor is lower than the maximum hydraulic oil temperature set in the controller.

[0017] As a preferred solution of the tower crane hydraulic jacking system control device described in the present invention: the motor provides power for hydraulic oil delivery through a hydraulic pump.

[0018] As a preferred solution of the tower crane hydraulic jacking system control device described in the present invention: an air filter and a liquid level temperature sensor are installed on the hydraulic oil tank.

[0019] As a preferred solution of the control device for the hydraulic jacking system of a tower crane described in the present invention: the reversing valve is composed of a two-position four-way reversing valve and an electromagnetic reversing valve connected in series.

[0020] As a preferred solution of the tower crane hydraulic jacking system control device described in the present invention: the throttle valve is a one-way throttle valve installed on the oil inlet pipe branch and the oil outlet pipe branch respectively.

[0021] As a preferred solution of the tower crane hydraulic jacking system control device described in the present invention: the integrated valve is connected to the jacking cylinder through a high-pressure hose.

[0022] As a preferred solution of the tower crane hydraulic jacking system control device described in the present invention: when the controller monitors that the real-time temperature of the liquid level temperature sensor is lower than 10% of the set maximum hydraulic oil temperature, the jacking cylinder works normally.

[0023] The present invention has the following beneficial effects: The present invention utilizes radiator temperature control and a throttle valve buffer circuit to mitigate hydraulic shock, ensuring a safe and reliable lifting process. Heat dissipation and cooling of the hydraulic lifting system extend the service life of the hydraulic oil and improve the safety factor of the tower crane lifting system. The radiator cools the system within the normal operating temperature range of the hydraulic oil. A safety buffer device, comprising a throttle valve and a reversing valve, is integrated into the tower crane's integrated valve assembly. A controller controls the reversal of the two-position, four-way reversing valve and the electromagnetic reversing valve, reducing the impact force during the reciprocating and stopping of the tower crane's lifting cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the hydraulic principle diagram of the present invention;

[0025] In the figure: 1-air filter, 2-hydraulic pump, 3-motor, 4-liquid level temperature sensor, 5-radiator, 6-pressure gauge, 7-two-position four-way reversing valve, 8-solenoid reversing valve, 9-integrated valve, 10-high-pressure hose, 11-balancing valve, 12-three-position four-way reversing valve, 13-lifting cylinder, 14-throttle valve, 15-back pressure valve, 16-safety valve, 17-low-pressure relief valve. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0029] Reference Figure 1 As a first embodiment of the present invention, a control device for a tower crane hydraulic jacking system is provided. The tower crane hydraulic jacking system includes a hydraulic oil tank and an oil pipe for conveying hydraulic oil; the oil pipe includes an oil inlet pipe and an oil outlet pipe; and includes a hydraulic pump 2 connected to the hydraulic oil tank, a liquid level temperature sensor 4, a radiator 5, an integrated valve 9, a jacking cylinder 13, and a controller.

[0030] The hydraulic pump 2 delivers hydraulic oil to the lifting cylinder 13 through the integrated valve 9;

[0031] The liquid level temperature sensor 4 is used to monitor the temperature of the hydraulic oil in the hydraulic oil tank and transmit the monitored real-time temperature to the controller via an electrical signal;

[0032] The integrated valve 9 includes a three-position four-way reversing valve 12 for controlling the reversing movement of the piston of the jacking oil cylinder 13, a reversing valve for controlling the start and stop of the hydraulic jacking system, a throttle valve 14 for realizing a buffering function during the reciprocating stroke of the jacking oil cylinder 13, a back pressure valve 15 for improving the performance of the tower crane hydraulic jacking system and preventing high-pressure oil from flowing into the hydraulic oil tank, a safety valve 16 for overload protection of the tower crane hydraulic jacking system, and a low-pressure relief valve 17 for opening when the tower crane hydraulic jacking system needs to be unloaded.

[0033] The radiator 5 is used to cool the hydraulic oil in the oil circuit;

[0034] The controller sets the maximum value of the hydraulic oil temperature and performs a logical judgment with the real-time temperature electrical signal received from the liquid level temperature sensor 4;

[0035] The lifting cylinder 13 includes a hydraulic cylinder and a two-way hydraulic lock 11 installed on the inlet and outlet oil pipes of the hydraulic cylinder to prevent the lifting cylinder from falling due to the weight of the load.

[0036] When the real-time temperature of the liquid level temperature sensor 4 is lower than the maximum hydraulic oil temperature set in the controller, the lifting cylinder 13 works normally;

[0037] When the real-time temperature of the liquid level temperature sensor 4 is greater than or equal to the maximum hydraulic oil temperature set in the controller, the controller starts the radiator 5 and sends signals to the reversing valve and the throttle valve at the same time. The reversing valve introduces the hydraulic oil in the oil circuit into the oil circuit branch pipe through the radiator 5 and flows into the hydraulic oil tank. The throttle valve 14 limits the flow of hydraulic oil into the jacking cylinder 13, prolonging the reversing movement time of the piston rod of the jacking cylinder 13, so as to reduce the hydraulic shock generated when the hydraulic cylinder piston is reversed, thereby achieving the purpose of safety and stability.

[0038] Until the real-time temperature monitored by the liquid level temperature sensor 4 is lower than the maximum hydraulic oil temperature set in the controller, the lifting cylinder 13 operates normally.

[0039] The motor 3 provides power for delivering hydraulic oil through the hydraulic pump 2 .

[0040] An air filter 1 and a liquid level temperature sensor 4 are installed on the hydraulic oil tank.

[0041] The reversing valve is composed of a two-position four-way reversing valve 7 and an electromagnetic reversing valve 8 connected in series.

[0042] The throttle valves are one-way throttle valves 14 respectively installed on the oil inlet branch and the oil outlet branch.

[0043] The integrated valve 9 is connected to the lifting cylinder 13 through a high-pressure hose 10 .

[0044] When the controller detects that the real-time temperature of the liquid level temperature sensor 4 is lower than 10% of the set maximum temperature of the hydraulic oil, the lifting cylinder 13 works normally.

[0045] Specifically, the motor 3 drives the hydraulic pump 2 as a power element, providing power to the actuator lifting cylinder 13. To facilitate control of the speed and direction of the actuator lifting cylinder 13, a control valve, such as a three-position, four-way reversing valve, can be provided. Oil pipes are connected to the two working oil ports of the three-position, four-way reversing valve. A radiator 5 is installed within the pump station where the hydraulic pump 2 resides. The hydraulic pump 2 is connected to the hydraulic oil tank, and the pump station also has heat dissipation holes at the radiator mounting location.

[0046] When lifting begins, the hydraulic lifting system activates. Motor 3 activates, and hydraulic oil flows from hydraulic pump 2 through the suction filter. Liquid level temperature sensor 4 activates, connecting the solenoid directional valve 8 and the spool of 2-position, 4-way directional valve 7 to the right, and the spool of 3-position, 4-way directional valve 12 to the left. The hydraulic oil flows from hydraulic pump 2 through 3-position, 4-way directional valve 12, 2-position, 4-way directional valve 7, and 8 before flowing into lifting cylinder 13. The piston rod of lifting cylinder 13 extends, raising the upper part of the tower crane. Liquid level temperature sensor 4 detects the real-time temperature of the hydraulic oil in the hydraulic system. The controller collects this signal and performs logical analysis. If the feedback data exceeds the set value, the controller issues a signal to control the spool of 2-position, 4-way directional valve 7 to the left, connecting the oil circuit. The hydraulic oil flowing from hydraulic pump 2 flows into the spool of 2-position, 4-way directional valve 7 to the left, then flows through low-pressure relief valve 17, enters the radiator, and returns to the oil tank. At the same time, solenoid directional valve 8 is switched to the left position, the safety device activates, and the lifting process smoothly stops, gradually returning to the pre-lift setting. Once the hydraulic system cools down, the controller detects that the temperature value of liquid level temperature sensor 4 is below the set value, and the electronic control system alerts the operator that the lifting operation can continue. Once the operator enters the continue command, the controller controls the spool of two-position four-way directional valve 7 to the left and the spool of solenoid directional valve 8 to the right, and the lifting operation continues.

[0047] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A control device for a tower crane hydraulic jacking system, wherein the tower crane hydraulic jacking system includes a hydraulic oil tank and an oil pipe for conveying hydraulic oil; the oil pipe includes an oil inlet pipe and an oil outlet pipe; and is characterized in that: It includes a hydraulic pump (2) connected to a hydraulic oil tank, a liquid level temperature sensor (4), a radiator (5), an integrated valve (9), a lifting cylinder (13), and a controller; The hydraulic pump (2) delivers hydraulic oil to the lifting cylinder (13) through the integrated valve (9); The liquid level temperature sensor (4) is used to monitor the temperature of the hydraulic oil in the hydraulic oil tank and transmit the monitored real-time temperature to the controller via an electrical signal; The integrated valve (9) includes a three-position four-way reversing valve (12) for controlling the reversing movement of the piston of the jacking oil cylinder (13), a reversing valve for controlling the start and stop of the hydraulic jacking system, a throttle valve (14) for realizing a buffering function during the reciprocating stroke of the jacking oil cylinder (13), a back pressure valve (15) for improving the performance of the tower crane hydraulic jacking system and preventing high-pressure oil from flowing into the hydraulic oil tank, a safety valve (16) for overload protection of the tower crane hydraulic jacking system, and a low-pressure relief valve (17) for opening when the tower crane hydraulic jacking system needs to be unloaded; The radiator (5) is used to cool the hydraulic oil in the oil circuit; The controller sets the maximum value of the hydraulic oil temperature and performs a logical judgment with the real-time temperature electrical signal received from the liquid level temperature sensor (4); The lifting oil cylinder (13) comprises a hydraulic oil cylinder and a bidirectional hydraulic lock (11) installed on the inlet and outlet oil pipes of the hydraulic oil cylinder to prevent the lifting oil cylinder from falling due to the action of the load gravity; The reversing valve is composed of a two-position four-way reversing valve (7) and an electromagnetic reversing valve (8) connected in series, and the electromagnetic reversing valve (8) and the throttle valve (14) are connected in parallel; When the real-time temperature of the liquid level temperature sensor (4) is lower than the maximum hydraulic oil temperature set in the controller, the lifting cylinder (13) operates normally; When the real-time temperature of the liquid level temperature sensor (4) is greater than or equal to the maximum hydraulic oil temperature set in the controller, the controller starts the radiator (5) and simultaneously sends a signal to the reversing valve and the throttle valve. The reversing valve introduces the hydraulic oil in the oil circuit into the oil circuit branch pipe through the radiator (5) and flows into the hydraulic oil tank. The throttle valve (14) limits the flow of hydraulic oil into the jacking oil cylinder (13), prolongs the time of the reversing movement of the piston rod of the jacking oil cylinder (13), and reduces the hydraulic shock generated when the hydraulic cylinder piston is reversing, thereby achieving the purpose of safety and stability. Until the real-time temperature monitored by the liquid level temperature sensor (4) is lower than the maximum hydraulic oil temperature set in the controller, the lifting cylinder (13) operates normally.

2. A tower crane hydraulic jacking system control device according to claim 1, characterized in that: The motor (3) provides power for delivering hydraulic oil through the hydraulic pump (2).

3. The tower crane hydraulic jacking system control device according to claim 1, characterized in that: An air filter (1) and a liquid level temperature sensor (4) are installed on the hydraulic oil tank.

4. The tower crane hydraulic jacking system control device according to claim 1, characterized in that: The throttle valve is a one-way throttle valve (14) installed on the oil inlet pipe branch and the oil outlet pipe branch respectively.

5. The tower crane hydraulic jacking system control device according to claim 1, characterized in that: The integrated valve (9) is connected to the lifting cylinder (13) via a high-pressure hose (10).

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