An auxiliary hydraulic system and control method for a mobile crawler crane

Abstract

This invention provides an auxiliary hydraulic system and its control method for a mobile crawler crane, which greatly improves system reliability and energy efficiency. The system includes an anti-tilt system, an auxiliary system, a cooler drive motor, a flow divider valve group, an auxiliary high-pressure pump, and a pump control valve group. The cooler drive motor is connected to the flow divider valve group, which is connected to the anti-tilt system, the auxiliary system, and the pump control valve group respectively. The auxiliary high-pressure pump is connected to the pump control valve group. The anti-tilt system, the auxiliary system, and the cooler drive system share a common hydraulic pump. Through logic control during system operation, the three systems share the hydraulic pump, while simultaneously optimizing the anti-tilt system and engine overspeed protection functions, greatly improving system reliability and energy efficiency.

Description

Technical Field

[0001] This invention belongs to the field of crane technology, specifically relating to an auxiliary hydraulic system and control method for a mobile crawler crane. Background Technology

[0002] Mobile crawler cranes typically use diesel engines to drive hydraulic pumps, providing the power source for the system. The main functions (including lifting, luffing, slewing, and traveling) employ either an open or closed hydraulic drive system. Auxiliary functions (including auxiliary assembly / disassembly systems, boom and super-lift boom anti-tipping systems, counterweight lifting and pushing systems, and other auxiliary systems) utilize open hydraulic systems.

[0003] In the existing system:

[0004] Anti-rollover system:

[0005] To avoid pressure loss or delayed oil replenishment in the anti-rollover cylinder due to the simultaneous operation of other auxiliary systems, the anti-rollover system uses a separate variable high-pressure plunger pump for oil supply. During system operation, feedback from the boom tension sensor controls the high and low pressure switching of the anti-rollover cylinder. The anti-rollover pump remains operational after the engine starts.

[0006] Auxiliary systems:

[0007] The auxiliary system uses a separate variable displacement high-pressure plunger pump. When any subsystem is operating, the auxiliary pump is automatically controlled to pressurize and supply oil. After the system stops operating, the auxiliary pump is unloaded and enters no-load operation.

[0008] Cooler drive system:

[0009] The cooler drive system uses an independent fixed-displacement gear pump for oil supply. It is also equipped with an unloading valve to depressurize and stop the cooler during diesel engine startup or when the oil temperature in the tank drops below a set value.

[0010] Engine overspeed protection system:

[0011] When the main function uses an open hydraulic system, gravitational potential energy is converted into system heat through a balance valve during load lowering. The engine does not experience any energy feedback. When the main function uses a closed hydraulic system design, gravitational potential energy is converted into torque from the hydraulic pump to reverse the engine during load lowering. Currently, the anti-torque performance of general-purpose engines in construction machinery is generally insufficient. During load lowering, if the reverse thrust torque converted by the system is large enough, the engine may be overspeeded. Under this condition, when the system detects engine overspeed, it controls the auxiliary pump to load to consume part or all of the reverse thrust torque, protecting the engine from overspeed.

[0012] The existing system design has the following drawbacks for its four functions:

[0013] Anti-rollover system:

[0014] The boom anti-tilt cylinder pressure control is designed according to a high and low pressure mode, which means that the boom is always subjected to unnecessary cylinder pressure, increasing the fatigue load on the boom.

[0015] The system adopts a high-low pressure switching mode. During the high-low pressure switching process, the boom will experience a step thrust change, which increases the fatigue load on the boom.

[0016] The anti-tilt system only consumes fuel during the luffing and lowering process, but the fuel supply system is always operating under a certain pressure, resulting in a certain degree of energy loss during operation and poor energy efficiency.

[0017] Auxiliary system fuel supply:

[0018] The auxiliary system uses a separate hydraulic pump. During system operation, the auxiliary system operates at a very low frequency. Even when unloaded, the auxiliary pump still consumes some drive power, resulting in poor energy efficiency.

[0019] An independent auxiliary fuel supply system increases the complexity of the overall system and raises the system failure rate.

[0020] Cooler drive system:

[0021] The cooler drive uses a separate fixed displacement pump system with an additional pressure control valve block, which increases the system failure rate.

[0022] When the oil temperature is low and the cooler is in standby mode, the cooler drive pump also experiences some power loss.

[0023] Engine overspeed protection system:

[0024] After the overspeed protection system is activated, the auxiliary pump applies a fixed torque to the system. During load lowering, if the load weight is insufficient to offset the applied torque, the engine will need to output a certain amount of power to drive it. This condition will result in additional energy loss. Summary of the Invention

[0025] The purpose of this invention is to overcome the shortcomings of the prior art and provide an auxiliary hydraulic system for a mobile crawler crane and its control method, which greatly improves the system's reliability and energy-saving performance.

[0026] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0027] This invention provides an auxiliary hydraulic system for a mobile crawler crane, including an anti-tilt system, an auxiliary system, a cooler drive motor, a flow divider valve group, an auxiliary high-pressure pump, and a pump control valve group;

[0028] The cooler drive motor is connected to a flow divider valve group, which is connected to the anti-tilt system, the auxiliary system, and the pump control valve group respectively; the auxiliary high-pressure pump is connected to the pump control valve group.

[0029] The anti-tilt system, auxiliary system, and cooler drive system share a common hydraulic pump.

[0030] Furthermore, the pump control valve assembly includes a main relief valve, a pilot-operated solenoid switch valve, and a pilot-operated proportional relief valve.

[0031] When the pilot solenoid valve is closed, the main relief valve operates at the maximum pressure set by the spring. After the pilot solenoid valve is opened, the pressure setting of the main relief valve is controlled by the pilot proportional relief valve. The pilot proportional relief valve is used to synchronously control the maximum output pressure of the main pump.

[0032] Furthermore, the diversion valve assembly includes a primary priority flow control valve, a secondary priority flow control valve, a pilot solenoid control valve, a check valve one, and a check valve two.

[0033] The primary priority flow control valve supplies oil to the anti-tilt system via its priority flow port. The oil supply pressure is synchronously controlled by the anti-tilt system pressure control valve via control port PI1. Once the anti-tilt system's oil supply is sufficient, the flow control valve core automatically switches, and the remaining flow flows to its bypass port, becoming the high-pressure oil source for the secondary priority flow control valve.

[0034] The secondary priority flow control valve supplies oil to the priority flow port of the auxiliary system and the bypass port of the cooler drive motor. The pilot solenoid control valve is used to select whether to supply oil to the auxiliary system. The maximum oil supply pressure of the auxiliary system is controlled synchronously by the pilot proportional relief valve controlled by the auxiliary high-pressure pump pressure through the PI2 port.

[0035] Furthermore, the anti-tilt system is a dual-cylinder design, including a manual four-way ball valve, a hydraulic check valve, an overflow valve, a solenoid switch valve, a check valve, and a proportional overflow valve;

[0036] The manual four-way ball valve is used to select whether the anti-tilt cylinder extends (working mode) or retracts.

[0037] The hydraulically controlled check valve serves as a pressure-maintaining valve for the hydraulic cylinder.

[0038] The pressure of the main relief valve of the anti-tilt cylinder is controlled by the pilot proportional relief valve 2 after passing through the pilot solenoid switch valve 2 and the check valve 3.

[0039] In a second aspect, the present invention provides a control method for an auxiliary hydraulic system of a mobile crawler crane, based on the system described in the first aspect, the method including a control method for an anti-tilt system, comprising:

[0040] The auxiliary high-pressure pump outputs pressurized oil to supply oil to the anti-tilt system through the primary priority flow control valve's priority flow port.

[0041] In the working mode, the pilot solenoid valve 2 is powered on and opened, and the pressure of the main relief valve of the anti-tilt cylinder is controlled by the pilot proportional relief valve 2.

[0042] Combined with the boom system's tension feedback, the system automatically sets the pilot proportional relief valve's pressure to the target value, thereby controlling the anti-tilt cylinder pressure.

[0043] The pilot proportional relief valve synchronously controls the primary priority flow control valve and the maximum output pressure of the priority flow port.

[0044] When the anti-tilting cylinder is stationary or extended, the primary priority flow control valve supplies oil to the system so that the cylinder pressure reaches the set value of the pilot proportional relief valve.

[0045] When the anti-tilt cylinder is retracted by the boom, the cylinder pressure is maintained at the setting of the pilot proportional relief valve 2. Excess pressure is released through the main relief valve of the anti-tilt cylinder.

[0046] The one-way valve generates a certain differential back pressure, which causes the main relief valve of the anti-tilting cylinder to start overflowing. This controls the primary priority flow control valve to close the priority oil supply circuit in advance, thus avoiding unnecessary flow overflow that could cause capacity loss.

[0047] Furthermore, the target value varies depending on the design requirements of the system's execution components (such as the drive pressure requirements of the cylinder or motor). Different systems will have different target values.

[0048] Furthermore, the method also includes a control method for auxiliary system oil supply, comprising:

[0049] After the primary priority flow control valve supplies oil to the anti-tilt system to meet the system requirements (the oil supply pressure reaches the anti-tilt system pressure setting), the valve core automatically switches direction, the oil inlet connects to the bypass port, and the remaining flow becomes the input oil source for the secondary priority flow control valve.

[0050] Oil is supplied through the priority flow port of the secondary priority flow control valve to prioritize the operation needs of the auxiliary system, and excess flow drives the cooler through the bypass port.

[0051] When the auxiliary system is working, the pilot solenoid control valve is shut off from power, and the secondary priority flow control valve opens to supply oil to the auxiliary system.

[0052] When the oil supply pressure exceeds the set value of the pilot proportional relief valve for the auxiliary pump pressure control, the default oil supply quantity meets the needs of the auxiliary system. The valve core of the secondary priority flow control valve reverses, the priority flow port closes, and the remaining flow is used to supply oil to the cooler drive system.

[0053] The valve core will switch back to the priority channel for oil supply once the pressure drops below the set value again.

[0054] In the standby state of the auxiliary system, the pilot solenoid control valve is de-energized and opened, the secondary priority flow control valve priority channel is closed, and all flow is supplied to the cooler drive motor through port P3.

[0055] The auxiliary system oil supply pressure is controlled by the high-pressure auxiliary pump through the pilot control port PI2 and the pilot proportional relief valve is controlled according to the preset value of the control system based on the working conditions.

[0056] Furthermore, the method also includes a control method for the cooler drive motor, comprising:

[0057] After the auxiliary pump prioritizes supplying oil to the anti-tilt system and auxiliary systems, the remaining flow is used to drive the cooler motor.

[0058] Furthermore, the method also includes a control method for an engine overspeed protection system, comprising:

[0059] Under normal system conditions, the pilot solenoid valve closes when de-energized, and the main relief valve limits the pressure to its own spring setting, thus providing a safety protection function.

[0060] The auxiliary high-pressure pump has a built-in pressure cut-off setting that is lower than the main relief valve setting, to avoid capacity loss and system overheating caused by large-flow overflow.

[0061] The maximum output pressure of the auxiliary high-pressure pump, i.e. the pressure cut-off value, is controlled by the pilot proportional relief valve.

[0062] Furthermore, the pump-controlled pilot proportional relief valve one is set to be greater than or equal to the anti-tilt system pressure (pilot proportional relief valve two) setting (set to 1.1 times);

[0063] When the auxiliary system is working, the pump-controlled pilot proportional relief valve is set to meet the preset pressure value of the auxiliary system.

[0064] When the auxiliary system is not working, the pump-controlled pilot proportional relief valve is set to meet the preset pressure value of the cooler drive.

[0065] The preset pressure value is calculated based on the actual system hydraulic actuator drive requirements; the cooler drive preset pressure value is obtained by calculating the torque required to drive the cooling fan and the hydraulic motor pressure requirements based on the cooler manufacturer's parameter requirements.

[0066] Furthermore, the control method of the engine overspeed protection system also includes: under engine overspeed protection conditions, the auxiliary high-pressure pump operates at a high flow rate. The system detects that the engine is being overspeeded by reverse thrust.

[0067] When the pilot solenoid valve is powered on and opened, the overflow pressure of the main relief valve is controlled by the pilot proportional relief valve.

[0068] The actual pressure cut-off value of the auxiliary pump (pump displacement returns to zero) is the sum of the pilot proportional relief valve setting and the differential pressure setting value of the pump's built-in pressure cut-off control valve (approximately 2 MPa).

[0069] Based on engine speed feedback, the overflow pressure is controlled by adjusting the pilot proportional relief valve. Based on actual engine speed feedback, if overspeeding occurs, the relief valve setting is increased at a certain rate until the engine speed drops to the permissible value. This provides the system with the necessary reverse thrust torque to protect the engine from overspeeding.

[0070] Furthermore, the control methods for the engine overspeed protection system also include:

[0071] Under engine overspeed protection conditions, the synchronous power supply closes the pilot solenoid control valve V23, switching the system to high-pressure mode. After switching, the system pressure can reach the auxiliary high-pressure pump set pressure value (V13), and some pressurized oil can be used to drive the cooler.

[0072] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0073] In mobile crawler crane systems, the anti-tilt system, auxiliary system, and cooler drive system rarely operate simultaneously. Independent hydraulic pumps are typically used only for system safety reasons (to avoid insufficient oil or pressure supply). Through logic control during system operation, the three systems share a hydraulic pump, while simultaneously optimizing the anti-tilt system and engine overspeed protection functions, significantly improving system reliability and energy efficiency.

[0074] Compared to traditional systems, sharing a hydraulic pump eliminates the extra drive power generated by multiple pumps. Under any operating condition, the system drive power is continuously reduced by more than 8KW (based on the hydraulic pump drive curve and the operating conditions), reducing system fuel consumption and making the system more environmentally friendly.

[0075] The new anti-tilt system adopts a stepless pressure adjustment method to avoid the boom being subjected to step-like hydraulic cylinder thrust, which greatly improves the boom's fatigue resistance.

[0076] The auxiliary system only has pressure and input when it is working. When it is not working, the oil supply system is in low-pressure mode, which improves the system life.

[0077] The engine overload protection system adjusts the pressure according to the load feedback to avoid excessive load and cause additional drive power input to the engine, thus achieving energy saving.

[0078] The overall system is simplified, reducing the failure rate. Attached Figure Description

[0079] Figure 1 This is a schematic diagram of the pump control valve assembly of the present invention;

[0080] Figure 2 This is a schematic diagram of the flow divider valve assembly of the present invention;

[0081] Figure 3 This is a schematic diagram of the anti-tilt system structure of the present invention;

[0082] Figure 4 This is a schematic diagram of the overall structure of the present invention;

[0083] In the diagram: P: High pressure port, T: Oil return port, D: Oil discharge port, PI: Pilot control port; S: Sensor. The number after each label represents the interface in the system, which is identified by different numbers.

[0084] V11, Main relief valve; V12, Pilot-operated solenoid valve 1; V13, Pilot-operated proportional relief valve 1;

[0085] V21, Primary priority flow control valve; V22, Secondary priority flow control valve; V23, Pilot-operated solenoid control valve; V24, Check valve one; V25, Check valve two;

[0086] V31, Manual four-way ball valve; V32, Check valve three; V33, Pilot-operated proportional relief valve two; V34, Pilot-operated solenoid switch valve two; V35, Anti-tilting cylinder main relief valve; V36, Hydraulic control check valve; D37, Dual cylinder. Detailed Implementation

[0087] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0088] In the description of this embodiment, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this embodiment.

[0089] Key term definitions:

[0090] Hydraulic system: A system that converts mechanical energy into hydraulic energy through a hydraulic pump to drive actuators (hydraulic motors or cylinders);

[0091] Crane boom anti-tilt system: a protective device for crawler cranes that prevents the boom from tilting backward and causing the crane to overturn or eliminates the potential for crane overturning by limiting and loading.

[0092] Auxiliary systems: crawler crane auxiliary disassembly and assembly system, counterweight lifting and pushing system. Example 1

[0093] This embodiment provides a novel hydraulic drive and control system. The attached diagram is a complete hydraulic schematic. The composition, function, and control logic of each control unit are described below.

[0094] 1. System Composition:

[0095] a pump control valve assembly:

[0096] The pump control valve assembly consists of a high-flow main relief valve V11, a pilot-operated solenoid valve V12, and a pilot-operated proportional relief valve V13. When V12 is closed, the main relief valve V11 operates at the maximum pressure set by the spring. After the pilot valve V12 is opened, the pressure setting of the main relief valve is controlled by the pilot-operated proportional relief valve V13. The pilot-operated proportional relief valve V13 synchronously controls the maximum output pressure of the main pump.

[0097] b. Diverter valve assembly:

[0098] The flow divider valve assembly consists of a primary priority flow control valve V21, a secondary priority flow control valve V22, a pilot solenoid control valve V23, a first check valve V24, and a second check valve V25. The primary priority flow control valve V21 supplies oil to the anti-tilt system via its priority flow port. The supply pressure is synchronously controlled by the anti-tilt system pressure control valve via control port PI1. Once the anti-tilt system's oil supply is satisfied, the flow control valve spool automatically switches, and the remaining flow flows to its bypass port, becoming the high-pressure input oil source for the secondary priority flow control valve V22.

[0099] The secondary priority flow control valve V22 supplies oil to the auxiliary system (priority flow port) and the cooler drive motor (bypass port). The pilot solenoid control valve V23 is used to select whether the auxiliary system supplies oil. The maximum oil supply pressure of the auxiliary system is controlled synchronously by the pilot control port PI2 and the pilot proportional relief valve V13 controlled by the auxiliary high-pressure pump pressure.

[0100] c Anti-rollover system:

[0101] The anti-tilt system typically features a dual-cylinder D37 design. A manual four-way ball valve V31 selects whether the anti-tilt cylinder extends (operating mode) or retracts. A hydraulically controlled check valve V36 maintains pressure in the cylinder. The pressure of the main relief valve V35 of the anti-tilt cylinder is controlled by a pilot-operated proportional relief valve V33 after passing through pilot-operated solenoid valve II V34 and check valve III V32.

[0102] 2. System working principle and control logic:

[0103] Anti-rollover system:

[0104] The auxiliary high-pressure pump outputs pressurized oil to supply the anti-tilt system through the primary priority flow control valve V21's priority flow port. In operating mode, the pilot solenoid valve V34 is powered on and opened, and the pressure of the anti-tilt cylinder's main relief valve V35 is controlled by the pilot proportional relief valve V33. Combined with the boom system's tension feedback, the system automatically sets the pressure of the pilot proportional relief valve V33 to the target value, thereby controlling the anti-tilt cylinder pressure. The pilot proportional relief valve V33 synchronously controls the maximum output pressure of the primary priority flow control valve V21's priority flow port. When the anti-tilt cylinder is stationary or extended, the primary priority flow control valve V21 supplies oil to the system, causing the cylinder pressure to reach the set value of the pilot proportional relief valve V33. When the anti-tilt cylinder is retracted by the boom's counter-push, the cylinder pressure maintains the setting of the pilot proportional relief valve V33; any excess pressure overflows through the anti-tilt cylinder's main relief valve V35. When the one-way valve V32 generates a certain differential back pressure, it causes the main relief valve V35 of the anti-tilting cylinder to start overflowing, thus controlling the primary priority flow control valve V21 to close the priority oil supply circuit in advance, avoiding unnecessary flow overflow that could cause capacity loss.

[0105] b. Auxiliary system fuel supply:

[0106] After the primary priority flow control valve V21 supplies oil to the anti-tilt system to meet system requirements (the oil supply pressure reaches the anti-tilt system pressure setting), the valve core automatically switches, connecting the inlet to the bypass port. The remaining flow becomes the input oil source for the secondary priority flow control valve V22. Oil is supplied through the priority flow port of the secondary priority flow control valve V22, prioritizing the auxiliary system's operational needs. Excess flow drives the cooler through the bypass port. When the auxiliary system is operating, the pilot solenoid control valve V23 is powered off, and the priority port of the secondary priority flow control valve V22 opens to supply oil to the auxiliary system. When the oil supply pressure exceeds the setting of the auxiliary pump pressure control pilot proportional relief valve V13, the default oil supply quantity meets the auxiliary system's needs. The valve core of the secondary priority flow control valve V22 switches, closing the priority flow port, and the remaining flow supplies oil to the cooler driving system. The valve core switches back to the priority channel oil supply state until the pressure drops below the setting again. In the auxiliary system standby state, the pilot solenoid control valve V23 is de-energized and opened, and the secondary priority flow control valve V22's priority channel is closed. All flow is supplied to the cooler drive motor through port P3. The auxiliary system oil supply pressure is controlled by the high-pressure auxiliary pump via the pilot control port PI2, and the pilot proportional relief valve V13 is controlled according to the preset value of the control system based on the operating conditions.

[0107] c. Cooler drive system:

[0108] Based on the descriptions in the previous two sections, the auxiliary pump prioritizes supplying oil to the anti-tilt system and auxiliary systems, with the remaining flow used to drive the cooler motor. The anti-tilt system operates with short periods of high flow or long periods of low flow. When the auxiliary system is operating, the system's heat generation is limited and will not cause the hydraulic oil tank temperature to rise. This design meets the system's operational requirements.

[0109] d Engine overspeed protection system:

[0110] Under normal system operation, the pilot solenoid valve V12 is de-energized and closed, and the main relief valve V11 limits the pressure to its own spring setting, serving as a safety protection function. The auxiliary high-pressure pump has a built-in pressure cut-off setting lower than the main relief valve V11 setting to avoid capacity loss and system overheating caused by large-flow overflow. The maximum output pressure (pressure cut-off value) of the auxiliary high-pressure pump is controlled by the pilot proportional relief valve V13.

[0111] The setting of the pump-controlled pilot proportional relief valve V13 must always be greater than or equal to the anti-tilt system pressure (setting of pilot proportional relief valve V33) (1.1 times the setting).

[0112] When the auxiliary system is working, the setting of the pump-controlled pilot proportional relief valve V13 needs to simultaneously meet the preset pressure value of the auxiliary system.

[0113] When the auxiliary system is not working, the pump-controlled pilot proportional relief valve V13 setting must simultaneously meet the preset pressure value of the cooler drive.

[0114] Under engine overspeed protection conditions, the auxiliary high-pressure pump needs to operate at a high flow rate to generate sufficient torque. The system detects that the engine is being overspeeded by reverse thrust. The pilot solenoid valve V12 is powered on and opens, and the overflow pressure of the main relief valve V11 is controlled by the pilot proportional relief valve V13. The actual pressure cut-off value of the auxiliary pump (pump displacement returns to zero) is the sum of the setting of the pilot proportional relief valve V13 and the differential pressure setting value (approximately 2 MPa) of the pump's built-in pressure cut-off control valve. Because the overflow pressure of the main relief valve V11 is equal to the setting of the pilot proportional relief valve V13, and the main relief valve setting is less than the pump pressure cut-off pressure, the main relief valve overflows at full flow, while the auxiliary high-pressure pump operates at a high displacement. Based on engine speed feedback, by adjusting the overflow pressure of the pilot proportional relief valve V13, the required reverse thrust torque can be provided to protect the engine from overspeed.

[0115] To prevent the system from failing to build high pressure due to both the cooler drive pressure and the anti-rollover system being in a low-pressure state, during engine overspeed protection conditions, it is necessary to synchronously power off the pilot solenoid control valve V23 to switch the system to high-pressure mode. After switching, the system pressure can reach the pressure value set by the auxiliary high-pressure pump pilot proportional relief valve V13, while some pressurized oil can be supplied for cooler drive.

[0116] When the engine is overspeeding (under heavy load), the auxiliary systems do not activate. Simultaneously, the anti-rollover system operates under low pressure requirements (the anti-rollover cylinder's thrust to the boom is inversely proportional to the load). Therefore, the engine overspeed protection system can provide a wide pressure adjustment range. Example 2

[0117] This embodiment provides a control method for an auxiliary hydraulic system of a mobile crawler crane. Based on the system described in the first aspect, the method includes a control method for an anti-tilt system, comprising:

[0118] Anti-rollover system:

[0119] The auxiliary high-pressure pump outputs pressurized oil to supply the anti-tilt system through the primary priority flow control valve V21's priority flow port. In operating mode, the pilot solenoid valve V34 is powered on and opened, and the pressure of the anti-tilt cylinder's main relief valve V35 is controlled by the pilot proportional relief valve V33. Combined with the boom system's tension feedback, the system automatically sets the pressure of the pilot proportional relief valve V33 to the target value, thereby controlling the anti-tilt cylinder pressure. The pilot proportional relief valve V33 synchronously controls the maximum output pressure of the primary priority flow control valve V21's priority flow port. When the anti-tilt cylinder is stationary or extended, the primary priority flow control valve V21 supplies oil to the system, causing the cylinder pressure to reach the set value of the pilot proportional relief valve V33. When the anti-tilt cylinder is retracted by the boom's counter-push, the cylinder pressure maintains the setting of the pilot proportional relief valve V33; any excess pressure overflows through the anti-tilt cylinder's main relief valve V35. When the one-way valve V32 generates a certain differential back pressure, it causes the main relief valve V35 of the anti-tilting cylinder to start overflowing, thus controlling the primary priority flow control valve V21 to close the priority oil supply circuit in advance, avoiding unnecessary flow overflow that could cause capacity loss.

[0120] b. Auxiliary system fuel supply:

[0121] After the primary priority flow control valve V21 supplies oil to the anti-tilt system to meet system requirements (the oil supply pressure reaches the anti-tilt system pressure setting), the valve core automatically switches, connecting the inlet to the bypass port. The remaining flow becomes the input oil source for the secondary priority flow control valve V22. Oil is supplied through the priority flow port of the secondary priority flow control valve V22, prioritizing the auxiliary system's operational needs. Excess flow drives the cooler through the bypass port. When the auxiliary system is operating, the pilot solenoid control valve V23 is powered off, and the priority port of the secondary priority flow control valve V22 opens to supply oil to the auxiliary system. When the oil supply pressure exceeds the setting of the auxiliary pump pressure control pilot proportional relief valve V13, the default oil supply quantity meets the auxiliary system's needs. The valve core of the secondary priority flow control valve V22 switches, closing the priority flow port, and the remaining flow supplies oil to the cooler driving system. The valve core switches back to the priority channel oil supply state until the pressure drops below the setting again. In the auxiliary system standby state, the pilot solenoid control valve V23 is de-energized and opened, and the secondary priority flow control valve V22's priority channel is closed. All flow is supplied to the cooler drive motor through port P3. The auxiliary system oil supply pressure is controlled by the high-pressure auxiliary pump via the pilot control port PI2, and the pilot proportional relief valve V13 is controlled according to the preset value of the control system based on the operating conditions.

[0122] c. Cooler drive system:

[0123] Based on the descriptions in the previous two sections, the auxiliary pump prioritizes supplying oil to the anti-tilt system and auxiliary systems, with the remaining flow used to drive the cooler motor. The anti-tilt system operates with short periods of high flow or long periods of low flow. When the auxiliary system is operating, the system's heat generation is limited and will not cause the hydraulic oil tank temperature to rise. This design meets the system's operational requirements.

[0124] d Engine overspeed protection system:

[0125] Under normal system operation, the pilot solenoid valve V12 is de-energized and closed, and the main relief valve V11 limits the pressure to its own spring setting, serving as a safety protection function. The auxiliary high-pressure pump has a built-in pressure cut-off setting lower than the main relief valve V11 setting to avoid capacity loss and system overheating caused by large-flow overflow. The maximum output pressure (pressure cut-off value) of the auxiliary high-pressure pump is controlled by the pilot proportional relief valve V13.

[0126] The setting of the pump-controlled pilot proportional relief valve V13 must always be greater than or equal to the anti-tilt system pressure (setting of pilot proportional relief valve V33) (1.1 times the setting).

[0127] When the auxiliary system is working, the setting of the pump-controlled pilot proportional relief valve V13 needs to simultaneously meet the preset pressure value of the auxiliary system.

[0128] When the auxiliary system is not working, the pump-controlled pilot proportional relief valve V13 setting must simultaneously meet the preset pressure value of the cooler drive.

[0129] Under engine overspeed protection conditions, the auxiliary high-pressure pump needs to operate at a high flow rate to generate sufficient torque. The system detects that the engine is being overspeeded by reverse thrust. The pilot solenoid valve V12 is powered on and opens, and the overflow pressure of the main relief valve V11 is controlled by the pilot proportional relief valve V13. The actual pressure cut-off value of the auxiliary pump (pump displacement returns to zero) is the sum of the setting of the pilot proportional relief valve V13 and the differential pressure setting of the pump's built-in pressure cut-off control valve (approximately 2 MPa). Because the main relief valve overflow pressure is equal to the setting of the pilot proportional relief valve V13, and the main relief valve setting is less than the pump pressure cut-off pressure, the main relief valve overflows at full flow, while the auxiliary high-pressure pump operates at a high displacement. Based on engine speed feedback, by adjusting the overflow pressure of the pilot proportional relief valve V13, the required reverse thrust torque can be provided to protect the engine from overspeed.

[0130] To prevent the system from failing to build high pressure due to both the cooler drive pressure and the anti-rollover system being in a low-pressure state, during engine overspeed protection conditions, it is necessary to synchronously power off the pilot solenoid control valve V23 to switch the system to high-pressure mode. After switching, the system pressure can reach the pressure value set by the auxiliary high-pressure pump pilot proportional relief valve V13, while some pressurized oil can be supplied for cooler drive.

[0131] When the engine is overspeeding (under heavy load), the auxiliary systems do not activate. Simultaneously, the anti-rollover system operates under low pressure requirements (the anti-rollover cylinder's thrust to the boom is inversely proportional to the load). Therefore, the engine overspeed protection system can provide a wide pressure adjustment range.

[0132] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0133] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0134] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0135] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0136] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A mobile crawler crane auxiliary hydraulic system, characterized in that, This includes an anti-tilt system, auxiliary systems, a cooler drive motor, a flow divider valve assembly, an auxiliary high-pressure pump, and a pump control valve assembly. The cooler drive motor is connected to a flow divider valve group, which is connected to the anti-tilt system, the auxiliary system, and the pump control valve group respectively; the auxiliary high-pressure pump is connected to the pump control valve group. The anti-tilt system, auxiliary system, and cooler drive motor share a hydraulic pump. The diversion valve assembly includes a primary priority flow control valve (V21), a secondary priority flow control valve (V22), a pilot solenoid control valve (V23), a check valve one (V24), and a check valve two (V25). The secondary priority flow control valve (V22) is connected to the primary priority flow control valve (V21), the pilot solenoid control valve (V23), the auxiliary system, and the cooler drive motor. The control port of the secondary priority flow control valve (V22) is connected to the power input port of the auxiliary system through one-way valve one (V24) and to the control port of the pump control valve group through one-way valve two (V25). The pilot solenoid control valve (V23) is connected to the control port of the secondary priority flow control valve (V22) and the oil tank. The primary priority flow control valve (V21) supplies oil to the anti-tilt system via its priority flow port; the oil supply pressure is synchronously controlled by the anti-tilt system pressure control valve via the control port PI1; after the anti-tilt system's oil supply is satisfied, the flow control valve core automatically switches, and the remaining flow flows to its bypass port, becoming the input high-pressure oil source for the secondary priority flow control valve (V22). The secondary priority flow control valve (V22) supplies oil to the priority flow port of the auxiliary system and the bypass port of the cooler drive motor; the pilot solenoid control valve (V23) is used to select whether the auxiliary system supplies oil; the maximum oil supply pressure of the auxiliary system is controlled synchronously by the auxiliary high pressure pump pressure control pilot proportional relief valve (V13) through the PI2 port.

2. The mobile track crane auxiliary hydraulic system of claim 1, wherein, The pump control valve group includes a main relief valve (V11), a pilot solenoid switch valve (V12), and a pilot proportional relief valve (V13). When the pilot solenoid valve 1 (V12) is closed, the main relief valve (V11) operates at the maximum pressure set by the spring; after the pilot solenoid valve 1 (V12) is opened, the pressure setting of the main relief valve (V11) is controlled by the pilot proportional relief valve 1 (V13); the pilot proportional relief valve 1 (V13) is used to synchronously control the maximum output pressure of the main pump.

3. The mobile track crane auxiliary hydraulic system of claim 2, wherein, The anti-tilt system is a dual-cylinder (D37) design, including a manual four-way ball valve (V31), a hydraulic check valve (V36), an anti-tilt cylinder main relief valve (V35), a pilot solenoid switch valve two (V34), a check valve three (V32), and a pilot proportional relief valve two (V33). The manual four-way ball valve (V31) is connected to the diversion valve group, oil tank, hydraulic control check valve (V36), anti-tilt cylinder main relief valve (V35), and pilot solenoid switch valve two (V34). One end of the one-way valve three (V32) is connected to the pilot solenoid switch valve two (V34), and the other end is connected to the pilot proportional relief valve two (V33); the other end of the pilot proportional relief valve two (V33) is connected to the manual four-way ball valve (V31). The hydraulic control check valve (V36) unidirectionally connects the manual four-way ball valve (V31) and the oil port of the anti-tilt system cylinder, and the hydraulic control port is connected to the manual four-way ball valve (V31). The anti-tilt cylinder main relief valve (V35) is connected to the manual four-way ball valve (V31) at one end and to the oil port of the anti-tilt system cylinder at the other end. One end of the pilot solenoid switch valve two (V34) is connected to the main relief valve (V35) of the anti-tilt cylinder, and the other end is connected to the one-way valve three (V32); The manual four-way ball valve (V31) is used to select the extension or retraction mode of the anti-tilt cylinder; The hydraulic control check valve (V36) serves as a pressure-holding valve for the hydraulic cylinder. The pressure of the main relief valve (V35) of the anti-tilt cylinder is controlled by the pilot proportional relief valve (V33) after passing through the pilot solenoid switch valve (V34) and the check valve (V32).

4. A mobile crawler crane auxiliary hydraulic system control method, characterized by, Based on the system as described in claim 3, the method includes a control method for an anti-rollover system, comprising: The auxiliary high-pressure pump outputs pressurized oil to supply oil to the anti-tilt system through the primary priority flow control valve (V21) priority flow port; In the working mode, the pilot solenoid switch valve 2 (V34) is powered on and opened, and the pressure of the anti-tilt cylinder main relief valve (V35) is controlled by the pilot proportional relief valve 2 (V33); Combined with the boom system tension feedback, the system automatically sets the pilot proportional relief valve 2 (V33) pressure to the target value, thereby controlling the anti-tilt cylinder pressure; Pilot proportional relief valve 2 (V33) synchronous control priority primary priority flow control valve (V21) priority flow port maximum output pressure; When the anti-tilting cylinder is stationary or extended, the primary priority flow control valve (V21) supplies oil to the system so that the cylinder pressure reaches the set value of the pilot proportional relief valve (V33). When the anti-tilt cylinder is retracted by the boom, the cylinder pressure is maintained at the setting of the pilot proportional relief valve 2 (V33). Excess pressure is released through the main relief valve (V35) of the anti-tilt cylinder. When the one-way valve three (V32) generates a certain differential back pressure, it causes the main relief valve (V35) of the anti-tilt cylinder to start overflowing, and controls the primary priority flow control valve (V21) to close the priority oil supply circuit in advance to avoid unnecessary flow overflow causing capacity loss.

5. The mobile track crane auxiliary hydraulic system control method of claim 4, wherein, The method also includes a control method for auxiliary system fuel supply, including: After the primary priority flow control valve (V21) supplies oil to the anti-tilt system and meets the system requirements, the oil supply pressure reaches the anti-tilt system pressure setting, the valve core automatically switches, the oil inlet connects to the bypass port, and the remaining flow becomes the input oil source for the secondary priority flow control valve (V22). Oil is supplied through the secondary priority flow control valve (V22) priority flow port to prioritize the operation needs of the auxiliary system, and excess flow drives the cooler through the bypass port. When the auxiliary system is working, the pilot solenoid control valve (V23) is shut off from power, and the secondary priority flow control valve (V22) opens to supply oil to the auxiliary system. When the oil supply pressure exceeds the setting of the high-pressure auxiliary pump control pilot proportional relief valve (V13), the default oil supply meets the needs of the auxiliary system. The valve core of the secondary priority flow control valve (V22) is reversed, the priority flow port is closed, and the remaining flow is used to supply oil to the cooler drive system. The valve core will switch back to the priority channel oil supply state until the pressure drops below the set value again. In the standby state of the auxiliary system, the pilot solenoid control valve (V23) is de-energized and opened, the secondary priority flow control valve (V22) priority channel is closed, and all flow is supplied to the cooler drive motor through the P3 port of the diversion valve group. The auxiliary system oil supply pressure is controlled by the high-pressure auxiliary pump through the pilot port PI2 and the pilot proportional relief valve (V13) according to the preset value of the control system based on the working conditions.

6. The mobile track crane auxiliary hydraulic system control method of claim 4, wherein, The method also includes a control method for the cooler drive motor, including: After the auxiliary pump prioritizes supplying oil to the anti-tilt system and auxiliary systems, the remaining flow is used to drive the cooler motor.

7. The mobile track crane auxiliary hydraulic system control method of claim 5, wherein, The method also includes a control method for an engine overspeed protection system, including: Under normal system operation, the pilot solenoid valve 1 (V12) is de-energized and closed, and the main relief valve (V11) limits the pressure to its own spring setting, thus providing a safety protection function. The auxiliary high-pressure pump has a built-in pressure cut-off setting that is lower than the main relief valve (V11) setting to avoid overflow causing capacity loss and system overheating; The maximum output pressure of the auxiliary high-pressure pump, i.e. the pressure cut-off value, is controlled by the pilot proportional relief valve (V13).

8. The control method for the auxiliary hydraulic system of a mobile crawler crane according to claim 7, characterized in that, The pump-controlled pilot proportional relief valve (V13) is set to be greater than or equal to the anti-tilt system pressure setting under all circumstances; When the auxiliary system is working, the pump-controlled pilot proportional relief valve (V13) is set to meet the preset pressure value of the auxiliary system; When the auxiliary system is not working, the pump-controlled pilot proportional relief valve (V13) is set to meet the preset pressure value of the cooler drive; The preset pressure value is calculated based on the actual system hydraulic actuator drive requirements; the cooler drive preset pressure value is obtained by calculating the torque required to drive the cooling fan and the hydraulic motor pressure requirements based on the cooler manufacturer's parameter requirements.

9. The control method for the auxiliary hydraulic system of a mobile crawler crane according to claim 8, characterized in that, The control method of the engine overspeed protection system also includes: under engine overspeed protection conditions, the auxiliary high-pressure pump works; the system detects that the engine is being overspeeded by reverse thrust; When the pilot solenoid valve 1 (V12) is powered on and opened, the overflow pressure of the main relief valve (V11) is controlled by the pilot proportional relief valve 1 (V13); The actual pressure cut-off value of the auxiliary pump is the sum of the setting of the pilot proportional relief valve (V13) and the differential pressure setting of the pump's built-in pressure cut-off control valve; Based on engine speed feedback, the overflow pressure is controlled by adjusting the pilot proportional overflow valve (V13). Based on the actual engine speed feedback, if overspeed is detected, the overflow valve setting is increased at a certain rate until the engine speed drops to the allowable value; this provides the reverse thrust torque required by the system and protects the engine from overspeed. Under engine overspeed protection conditions, the synchronous power supply closes the pilot solenoid control valve (V23), switching the system to high-pressure mode. After switching, the system pressure can reach the pressure value set by the auxiliary high-pressure pump pilot proportional relief valve (V13), and at the same time, some pressure oil can be provided for cooler drive.

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