Dumper and control method

Abstract

The invention provides a dumper and a control method thereof, a hydraulic cooling system comprises a pump displacement control module, a plunger pump, a motor and a fan, the pump displacement control module is electrically connected with the plunger pump, and an output shaft of the motor is connected with the fan; when the temperature of the cooling liquid is lower than 0 DEG C, the current of the pump displacement control module output by the control system is 500mA-550mA, and the motor has no rotating speed output; when the temperature of the cooling liquid ranges from 0 DEG C to 83 DEG C, the control system outputs the current of the pump displacement control module to be 400 mA, and the motor outputs a low rotating speed; when the temperature of the cooling liquid ranges from 83 DEG C to 93 DEG C, the current of the pump displacement control module ranges from 400 mA to 120 mA, and the displacement of the plunger pump changes along with the change of the current of the pump displacement control module; when the temperature of the cooling liquid is larger than 93 DEG C, the current of the pump displacement control module is smaller than 120 mA, and the rotating speed of the motor reaches the maximum. According to the hydraulic cooling system of the dumper, different motor rotating speeds can be adjusted in real time according to different temperatures, the system reliability is high, the structure is simple, and arrangement and maintenance are easy.

Description

Technical Field

[0001] The present invention relates to the technical field of heat dissipation systems, and in particular to a dump truck and a control method thereof. Background Art

[0002] Mining dump trucks are specialized transport equipment used in open-pit mining and large-scale earthwork construction. Electric-driven dump trucks are the preferred equipment for green mining, enjoying the trust of mining customers for their high energy efficiency, environmental friendliness, noise reduction, reliability, high control precision, and advanced automation.

[0003] The cooling system of electric dump trucks currently uses an engine-directed fan drive system. Specifically, the cooling system consists of an engine, a belt, and a fan. There are currently two drive methods: one in which the engine drives the fan via a drive belt, and the other in which the engine directly drives the fan. Both drive methods directly correlate fan speed with engine speed, requiring adjustment only by varying engine speed: high fan speed at high engine speeds and low fan speed at low engine speeds. When the water and oil temperatures are low, the fan speed should be lowered or even stopped. However, since the fan is directly driven by the engine and operating conditions require the engine to operate in the intermediate or high speed range, the fan speed is higher in these situations. This creates a problem of redundant cooling power, increasing engine fuel consumption and user costs. Furthermore, since the fan is directly driven by the engine, fan speed cannot be adjusted autonomously, increasing fan noise with increasing engine speed. This also intensifies the engine's vibration, which is transmitted to the fan. Furthermore, the drive belt is susceptible to wear and fatigue fracture, increasing the probability of system failure and reducing reliability. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a dump truck, the hydraulic cooling system of which can adjust different motor speeds in real time according to different temperatures of the engine coolant, the system has high reliability, simple structure, and is easy to arrange and maintain.

[0005] The present invention provides a dump truck, comprising an engine, a control system and a hydraulic cooling system, wherein the control system is connected to the engine, and the hydraulic cooling system comprises a pump displacement control module, a plunger pump, a fuel tank, a motor and a fan, the control system of the dump truck is electrically connected to the pump displacement control module, the pump displacement control module is electrically connected to the plunger pump, the pump displacement control module can control the displacement of the plunger pump, the plunger pump is communicated with the fuel tank, the plunger pump is communicated with the motor through a pipeline, the output shaft of the motor is connected to the fan, and the fan is used to dissipate heat for the radiator of the dump truck; when the control system detects that the coolant temperature of the engine is lower than 0°C, the control system outputs a current of 500mA to 550mA to the pump displacement control module mA, so that the plunger pump is at zero displacement, the motor has no speed output, and the hydraulic cooling system does not work; when the control system detects that the coolant temperature of the engine is between 0°C and 83°C, the control system outputs a current of 400mA to the pump displacement control module, so that the plunger pump outputs a first displacement value, the motor outputs a speed matching the first displacement value, and the hydraulic cooling system can meet the thermal balance performance at this time; when the control system detects that the coolant temperature of the engine is between 83°C and 93°C, the control system outputs a current of 400mA to the pump displacement control module mA, the displacement of the plunger pump changes according to the current change of the pump displacement control module, and the hydraulic cooling system maintains dynamic thermal balance according to the working conditions at this time; when the control system detects that the coolant temperature of the engine is greater than 93°C, the control system outputs a current of less than 120mA to the pump displacement control module, the plunger pump outputs the maximum displacement, and the motor speed reaches the maximum; when the pump displacement control module loses power, the plunger pump outputs the maximum displacement, and the motor speed reaches the maximum.

[0006] In one embodiment, when the control system detects that the hydraulic oil temperature in the oil tank is greater than 80° C., the pump displacement control module controls the plunger pump to output a maximum displacement, and the motor speed reaches a maximum.

[0007] In one embodiment, the hydraulic cooling system further includes an oil replenishment pump and a filter. The oil replenishment pump is connected between the oil tank and the filter. The filter is provided with a first oil outlet, which is connected to the pump displacement control module. The oil in the oil tank flows into the plunger pump after passing through the oil replenishment pump, the first oil outlet and the pump displacement control module.

[0008] In one embodiment, the hydraulic cooling system further includes an oil replenishment overflow valve, the filter is provided with a second oil outlet, the oil replenishment overflow valve is communicated with the second oil outlet, and the oil replenishment overflow valve is used for replenishing oil and stabilizing pressure.

[0009] In one embodiment, the plunger pump is provided with a first oil circuit and a second oil circuit, the first oil circuit being connected to a first oil port of the motor, and the second oil circuit being connected to a second oil port of the motor, and the direction of the motor is changed by supplying oil to the first oil circuit or the second oil circuit; the hydraulic cooling system further comprises a first pressure cut-off valve and a second pressure cut-off valve, the first pressure cut-off valve being connected to the pump displacement control module and the first oil circuit, and when the plunger pump supplies oil to the first oil circuit and the oil pressure of the first oil circuit increases to a pressure value of the first pressure cut-off valve, the first pressure cut-off valve opens, and the oil in the first oil circuit overflows to the pump displacement control module, thereby reducing the displacement of the plunger pump; the second pressure cut-off valve being connected to the pump displacement control module and the second oil circuit, and when the plunger pump supplies oil to the second oil circuit and the oil pressure of the second oil circuit increases to a pressure value of the second pressure cut-off valve, the second pressure cut-off valve opens, and the oil in the second oil circuit overflows to the pump displacement control module, thereby reducing the displacement of the plunger pump.

[0010] In one embodiment, the hydraulic cooling system includes a first multifunctional valve and a second multifunctional valve, wherein the first input end of the first multifunctional valve is connected to the second oil port, the first output end of the first multifunctional valve is connected to the first oil circuit, the second input end of the second multifunctional valve is connected to the second oil port, and the second output end of the second multifunctional valve is connected to the second oil circuit.

[0011] In one embodiment, the first multifunctional valve includes a first overflow valve and a first check valve arranged in parallel, and the second multifunctional valve includes a second overflow valve and a second check valve arranged in parallel; when the plunger pump supplies oil to the first oil circuit, the first overflow valve works, the second check valve opens and replenishes the oil in the second oil circuit; when the plunger pump supplies oil to the second oil circuit, the second overflow valve works, the first check valve opens and replenishes the oil in the first oil circuit.

[0012] In one embodiment, the current A1 has a value ranging from 500 mA to 550 mA; the current A2 has a value of 400 mA; the current A3 has a value ranging from 400 mA to 120 mA; and the current A4 has a value less than 120 mA.

[0013] In one embodiment, the hydraulic cooling system further includes a motor displacement control module, which is connected between the first oil circuit and the second oil circuit. When the displacement of the plunger pump is insufficient, the speed of the motor can be increased by reducing the displacement of the motor.

[0014] In one embodiment, the hydraulic heat dissipation system further includes a flushing valve connected between the first oil circuit and the second oil circuit, and the flushing valve is used to cool the oil in the hydraulic heat dissipation system.

[0015] The present invention also relates to a control method for the above-mentioned hydraulic cooling system, the control method comprising: The engine thermostat detects the temperature of the engine's hydraulic oil and coolant and feeds the data back to the control system, which determines the temperature; When the control system determines that the coolant temperature is lower than 0°C, the control system outputs a current value of 500mA to 550mA to the pump displacement control module, the plunger pump outputs zero oil displacement, and the motor has no speed output; When the control system determines that the coolant temperature is between 0° C. and 63° C., the control system changes the current value of the pump displacement control module to 400 mA, the plunger pump outputs a first displacement value, and the motor outputs a speed matching the first displacement value; When the control system determines that the coolant temperature is between 63° C. and 93° C., the control system proportionally changes the current value of the pump displacement control module between 400 mA and 120 mA, and the displacement of the plunger pump changes proportionally; When the control system determines that the coolant temperature is above 93° C., the control system changes the current value of the pump displacement control module to be less than 120 mA, the plunger pump outputs the maximum displacement value, and the motor rotates at the maximum speed; When the pump displacement control module loses power, the plunger pump outputs a large displacement, causing the motor to rotate at a maximum speed; During the operation of the dump truck, the control system detects and determines the hydraulic oil temperature of the oil tank and the coolant temperature of the engine in real time, so as to adjust the speed of the motor in real time according to different temperature ranges.

[0016] In one embodiment, when the control system detects that the hydraulic oil temperature is greater than 80° C., the pump displacement control module controls the plunger pump to output a maximum displacement, and the motor speed reaches a maximum.

[0017] The hydraulic cooling system of the dump truck of the present invention detects and determines the hydraulic oil temperature of the oil tank and the coolant temperature of the engine through the control system, and outputs or changes the current of the pump displacement control module according to different temperature ranges, so that the pump displacement control module controls the pump displacement and rotation direction of the plunger pump. It can be understood that the control system directly controls the speed of the motor through the pump displacement control module, and there is no direct connection between the speed of the motor and the engine. Compared with the connection method between the engine and the fan in the prior art, the vibration of the fan is reduced and the service life is increased, and the low temperature and low speed control characteristics reduce the fan noise and improve human-machine comfort; even if the control system fails or the pump displacement control module loses power, the plunger pump can automatically return to the large displacement output, so that the heat dissipation performance is maximized to meet the heat dissipation requirements. Therefore, the hydraulic cooling system can adjust different motor speeds according to different temperature ranges, and has the characteristics of fan speed temperature adaptation, temperature closed-loop control, and real-time speed monitoring; in addition, the plunger pump and motor components are highly centralized, with a simple structure, easy layout and maintenance, and convenient detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 It is a structural schematic diagram of the hydraulic heat dissipation system of the present invention.

[0020] Figure 2 It is a hydraulic principle diagram of the hydraulic heat dissipation system of the present invention.

[0021] Figure 3 Graph showing the relationship between current and temperature in the hydraulic cooling system of the present invention.

[0022] Explanation of the accompanying reference numerals: first oil circuit 11; second oil circuit 12; pump displacement control module 111; reversing valve 111a; servo piston 111b; plunger pump 112; oil tank 113; oil supply pump 114; filter 115; bypass valve 1151; clogging alarm 1152; oil supply relief valve 116; first pressure cut-off valve 117; second pressure cut-off valve 118; first multi-function valve 121; first relief valve 1211; first one-way valve 1212; first stop valve 1213; second multi-function valve 122; second relief valve 1221; second one-way valve 1222; second stop valve 1223; motor 131; motor displacement control module 132; flushing valve 133; speed sensor 134; fan 15; first input terminal m; second output terminal n.

[0023] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0024] Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the described embodiments are merely some, and not all, of the embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the description of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0025] In the description of the present invention, unless otherwise specified or limited, the terms "disposed," "installed," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms based on the specific circumstances.

[0026] The directions or positional relationships indicated by terms such as "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience and simplification of description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0027] The terms "first," "second," "third," etc. are merely used to distinguish between elements of similar nature and do not indicate or imply relative importance or a particular order.

[0028] The terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of elements other than the listed elements and may also include additional elements not specifically listed.

[0029] like Figures 1 to 3 As shown, the dump truck includes an engine, a control system and a hydraulic cooling system. The control system is connected to the engine. The hydraulic cooling system includes a pump displacement control module 111, a plunger pump 112, an oil tank 113, a motor 131 and a fan 15. The hydraulic cooling system is used to dissipate heat from the hydraulic oil in the oil tank 113 and the coolant of the engine. The control system of the dump truck is electrically connected to the pump displacement control module 111, and the pump displacement control module 111 is electrically connected to the plunger pump 112. The pump displacement control module 111 can control the displacement of the plunger pump 112. The plunger pump 112 is connected to the oil tank 113, and the plunger pump 112 is connected to the motor 131 through a pipeline. The output shaft of the motor 131 is connected to the spline of the fan 15. Motor 131 is a plunger motor. Compared with gear motors and cycloid motors, plunger motors are suitable for high-pressure fields and are mainly used in heavy machinery and high-load equipment. They can work stably under extreme conditions. The pump displacement control module 111 changes the displacement of the plunger pump 112 and the oil supply direction of the plunger pump 112 so that the plunger motor can rotate forward and reverse. The purpose of reversal is to remove dust and impurities on the fan 15 to prevent dust and impurities from affecting the heat dissipation performance.

[0030] like Figure 2 and Figure 3 As shown, when the control system detects that the engine coolant temperature is lower than T1, where T1 is 0°C, the control system outputs a current value of 500mA to 550mA to the pump displacement control module 111, such as 500mA, 530mA, or 550mA, so that the plunger pump 112 is at zero displacement. At this time, the motor 131 has no speed output, and the hydraulic cooling system does not work. When the control system detects that the coolant temperature is between T1 and T2, when T2 is 83°C, T1~T2 is 0°C~83°C, and the coolant temperature is, for example, 10°C, 30°C, 53°C, 63°C or 83°C, the control system outputs a current value of 400mA to the pump displacement control module 111, causing the plunger pump 112 to output a first displacement value, and the motor 131 to output a speed matching the first displacement value, i.e., a relatively low speed, so that the hydraulic cooling system can meet the thermal balance performance at this time; When the control system detects that the coolant temperature is between T2 and T3, when T3 is 93°C, T2~T3 is 83°C~93°C, and the coolant temperature is, for example, 84°C, 85°C, 90°C or 93°C, etc., the control system outputs a current range value of the pump displacement control module 111 of 400mA~120mA, such as 350mA, 300mA, 330mA, 200mA or 120mA, etc. The displacement of the plunger pump 112 changes according to the current change of the A3 pump displacement control module 111, and the hydraulic cooling system maintains dynamic thermal balance according to the working conditions at this time.

[0031] When the control system detects that the coolant temperature is greater than T3, when T3 is 93°C, that is, greater than 93°C, the control system outputs a current value of less than 120mA to the pump displacement control module 111, the plunger pump 112 outputs the maximum displacement, and the motor 131 reaches the maximum speed; The hydraulic cooling system primarily determines the temperature of the coolant, with the temperature of the hydraulic oil in the tank 113 serving as an auxiliary factor. When the control system detects that the hydraulic oil temperature is greater than 80°C, the pump displacement control module 111 controls the plunger pump 112 to output the maximum displacement, and the motor 131 rotates at its maximum speed. Regardless of the coolant temperature range, the plunger pump 112 outputs at its maximum displacement, causing the motor 131 and the fan 15 to operate at their maximum speeds. When the pump displacement control module 111 loses power, the plunger pump 112 outputs the maximum displacement and the motor 131 rotates at the maximum speed. Therefore, even if the control system fails, the heat dissipation requirement can be met.

[0032] It is understandable that during the operation of the dump truck, the control system detects and determines the temperature of the hydraulic oil in the oil tank and the temperature of the engine coolant in real time, so as to adjust the speed of the motor 131 in real time according to different temperature ranges. For example, the engine's thermostat detects the coolant temperature. When the thermostat detects that the coolant temperature is 90°C, the control system outputs a corresponding current value to the pump displacement control module 111 between 400 mA and 120 mA. At this time, the pump displacement control module 111 controls the displacement of the plunger pump 112 to increase, so that the motor 131 reaches an ideal speed. The connection between the fan 15 and the motor 131 makes the fan 15 and the motor 131 have the same speed, so that the fan 15 dissipates heat for the hydraulic oil and coolant; the thermostat detects the coolant temperature in real time. When the thermostat detects that the coolant temperature drops to 83°C, the control system changes the current of the pump displacement control module 111 to 400 mA. At this time, the plunger pump 112 outputs a small displacement and the motor 131 rotates at a low speed; this is to achieve different motor 131 speed adjustment according to different temperature ranges, with the characteristics of fan 15 speed temperature adaptation, temperature closed-loop control, and real-time speed monitoring.

[0033] The hydraulic cooling system of the dump truck of the present invention detects and determines the temperature of the hydraulic oil in the oil tank 113 and the coolant of the engine through the control system, outputs or changes the current of the pump displacement control module 111 according to different temperature ranges, so that the pump displacement control module 111 controls the pump displacement and rotation direction of the plunger pump 112. It can be understood that the control system directly controls the speed of the motor 131 through the pump displacement control module 111. There is no direct connection between the speed of the motor 131 and the engine. Compared with the connection method between the engine and the fan 15 in the prior art, the vibration of the fan 15 is reduced and the service life is increased. The high temperature and low speed control characteristics reduce the noise of the fan 15 and improve the human-machine comfort; even if the control system fails or the pump displacement control module 111 loses power, the plunger pump 112 can automatically return to the large displacement output, so that the heat dissipation performance is maximized to meet the heat dissipation needs. Therefore, the hydraulic heat dissipation system can adjust the speed of the motor 131 according to different temperature ranges, and has the characteristics of fan 15 speed temperature adaptation, temperature closed-loop control, and real-time speed monitoring; in addition, the plunger pump 112 and motor 131 components are highly centralized, with a simple structure, easy layout and maintenance, and convenient detection.

[0034] Preferably, the hydraulic cooling system further comprises an oil replenishment pump 114 and a filter 115. The oil replenishment pump 114 is connected between the oil tank 113 and the filter 115. The oil replenishment pump 114 is used to replenish oil leaked from the hydraulic cooling system and the oil flushed out by the flushing valve 133 integrated in the motor 131. The filter 115 is used to remove impurities from the oil entering the hydraulic cooling system, preventing heat dissipation problems caused by impurities being stuck, which can effectively improve the service life of the components and the reliability of the hydraulic cooling system. The filter 115 has a first oil outlet and a second outlet. The first oil outlet is connected to the pump displacement control module 111. The oil in the oil tank 113 flows into the plunger pump 112 after passing through the oil replenishment pump 114, the first oil outlet, and the pump displacement control module 111. The hydraulic cooling system further comprises an oil replenishment relief valve 116, which is connected to the second oil outlet. The oil replenishment relief valve 116 is used to replenish oil and stabilize pressure to prevent the plunger from hitting the cylinder due to insufficient oil replenishment. The oil replenishment relief valve 116 is normally open during operation. In this embodiment, the filter 115 is provided with a bypass valve 1151 and a clogging alarm 1152. The clogging alarm 1152 will promptly alarm and prompt replacement when the filter element of the filter valve is clogged.

[0035] Preferably, the pump displacement control module 111 includes a reversing valve 111a and a servo piston 111b. After the oil flows out from the first oil port of the filter 115, it flows through the reversing valve 111a and the servo piston 111b in sequence. The reversing valve 111a is used to control the forward or reverse rotation of the plunger pump 112, and the servo piston 111b controls the swash plate swing angle of the plunger pump 112 to achieve the purpose of controlling the displacement of the plunger pump 112.

[0036] Preferably, the plunger pump 112 is provided with a first oil circuit 11 and a second oil circuit 12, the first oil circuit 11 is connected to the first oil port of the motor 131, and the second oil circuit 12 is connected to the second oil port of the motor 131, and the direction of the motor 131 is changed by supplying oil to the first oil circuit 11 or the second oil circuit 12.

[0037] Preferably, the hydraulic heat dissipation system further includes a first pressure cut-off valve 117 and a second pressure cut-off valve 118. The first pressure cut-off valve 117 connects the pump displacement control module 111 with the first oil circuit 11. When the plunger pump 112 supplies oil to the first oil circuit 11 and the oil pressure of the first oil circuit 11 increases to the pressure value of the first pressure cut-off valve 117, the first pressure cut-off valve 117 opens, and the oil in the first oil circuit 11 overflows to the pump displacement control module 111, thereby reducing the displacement of the plunger pump 112. The pressure cut-off valve 118 connects the pump displacement control module 111 and the second oil circuit 12. When the plunger pump 112 supplies oil to the second oil circuit 12 and the oil pressure in the second oil circuit 12 increases to the pressure value of the second pressure cut-off valve 118, the second pressure cut-off valve 118 opens, and the oil in the second oil circuit 12 overflows to the pump displacement control module 111, reducing the displacement of the plunger pump 112; the first pressure cut-off valve 117 and the second pressure cut-off valve 118 can prevent damage to components due to continuous overflow of large displacement.

[0038] Preferably, the hydraulic cooling system includes a first multifunctional valve 121 and a second multifunctional valve 122, the first input end m of the first multifunctional valve 121 is connected to the second oil port, the first output end of the first multifunctional valve 121 is connected to the first oil circuit 11, the second input end n of the second multifunctional valve 122 is connected to the second oil port, and the second output end of the second multifunctional valve 122 is connected to the second oil circuit 12.

[0039] Preferably, the first multifunctional valve 121 includes a first overflow valve 1211 and a first one-way valve 1212 arranged in parallel, and the second multifunctional valve 122 includes a second overflow valve 1221 and a second one-way valve 1222 arranged in parallel; when the plunger pump 112 supplies oil to the first oil circuit 11, the first overflow valve 1211 works, the second one-way valve 1222 opens and replenishes the oil in the second oil circuit 12; when the plunger pump 112 supplies oil to the second oil circuit 12, the second overflow valve 1221 works, the first one-way valve 1212 opens and replenishes the oil in the first oil circuit 11.

[0040] Preferably, the first multifunctional valve 121 also includes a first stop valve 1213, the first overflow valve 1211 and the first one-way valve 1212 are respectively arranged in parallel with the first stop valve 1213, and the second multifunctional valve 122 also includes a second stop valve 1223, the second overflow valve 1221 and the second one-way valve 1222 are respectively arranged in parallel with the second stop valve 1223. When the engine fails and the dump truck needs to be towed, the first stop valve 1213 and the second stop valve 1223 are opened at the same time.

[0041] Preferably, the oil charge pump 114 , the filter 115 , the oil charge relief valve 116 , the first pressure cut-off valve 117 , the second pressure cut-off valve 118 , the first multifunctional valve 121 and the second multifunctional valve 122 are respectively integrated into the plunger pump 112 .

[0042] Preferably, the hydraulic cooling system also includes a motor displacement control module 132, which is connected between the first oil circuit 11 and the second oil circuit 12. The motor displacement control module 132 can change the displacement of the motor 131. When the displacement of the plunger pump 112 is insufficient, the speed of the motor 131 can be increased by reducing the displacement of the motor 131.

[0043] Preferably, the hydraulic cooling system further includes a flushing valve 133 connected between the first oil circuit 11 and the second oil circuit 12 . The flushing valve 133 is used to replace the hot oil in the hydraulic cooling system to meet the oil temperature requirement of the hydraulic cooling system.

[0044] Preferably, the hydraulic cooling system also includes a speed sensor 134, which is electrically connected to the motor 131. The speed sensor 134 is used to control the system to detect and correct control parameters, that is, to detect the speed of the motor 131. It is used when debugging the hydraulic cooling system to calibrate the relationship between the current and the speed of the fan 15, because there is a difference between the current and the speed of the fan 15 of motors 131 of different models or sizes.

[0045] Preferably, the motor displacement control module 132 , the flushing valve 133 and the speed sensor 134 are respectively integrated into the motor 131 .

[0046] The present invention also relates to a control method for the above-mentioned hydraulic cooling system, the control method comprising: The engine's thermostat detects the engine's coolant temperature and feeds the data back to the control system, which then determines the temperature; When the control system determines that the coolant temperature is lower than 0°C, the control system outputs a current value of 500mA to 550mA to the pump displacement control module 111, the plunger pump 112 outputs an oil displacement of zero, and the motor 131 has no speed output; When the control system determines that the coolant temperature is between 0°C and 83°C, the control system changes the current value of the pump displacement control module 111 to 400mA, the plunger pump 112 outputs the first displacement value, and the motor 131 outputs a speed matching the first displacement value; When the control system determines that the coolant temperature is between 83°C and 93°C, the control system proportionally changes the current value of the pump displacement control module 111 between 400mA and 120mA, and the displacement of the plunger pump 112 is proportionally changed; it is understandable that when the current value of the pump displacement control module 111 is between 400mA and 120mA, the displacement output by the plunger pump is greater than the first displacement value; When the control system determines that the coolant temperature is above 93° C., the control system changes the current value of the pump displacement control module 111 to be less than 120 mA, the plunger pump 112 outputs the maximum displacement value, and the motor 131 rotates at the maximum speed.

[0047] The oil tank 113 is equipped with a temperature sensor that detects the temperature of the hydraulic oil in the oil tank 113 and feeds this temperature back to the control system. When the control system determines that the hydraulic oil temperature is greater than 80°C, the pump displacement control module 111 controls the plunger pump 112 to output the maximum displacement and the motor 131 to rotate at the maximum speed. At this time, regardless of the coolant temperature in any range, the plunger pump 112 outputs at the maximum displacement, causing the motor 131 and the fan 15 to operate at the maximum speed. When the pump displacement control module 111 loses power or the control system fails, the plunger pump 112 outputs a large displacement, causing the motor 131 to rotate at the maximum speed; During the operation of the dump truck, the control system detects and determines the hydraulic oil temperature of the oil tank 113 and the coolant temperature of the engine in real time, so as to adjust the speed of the motor 131 in real time according to different temperature ranges.

[0048] Therefore, the control method can adjust the speed of the motor 131 according to different temperature ranges, and has the characteristics of temperature adaptation of the fan 15 speed, temperature closed-loop control and real-time speed detection, so that the performance of the hydraulic control cooling system is always in the optimal working range, the engine power utilization rate is high, and fuel consumption is reduced. Among them, the temperature closed-loop control refers to the control system detecting the engine coolant temperature and the hydraulic oil temperature in the fuel tank 113, changing the speed of the motor 131 and the fan 15 by changing the current of the pump displacement control module 111, and then detecting the temperature of the coolant and hydraulic oil after the fan 15 speed is changed, and comparing the temperature before and after the fan 15 speed is changed to control the fan 15 speed in real time; it can be understood that the speed of the motor 131 is equal to the speed of the fan 15; in addition, the pump displacement control module 111 has the characteristic of returning to maximum displacement when power is lost. This characteristic can ensure that when the control system fails (causing the pump displacement control module 111 to lose power), the hydraulic cooling system is in the maximum heat dissipation state, with high reliability, greater safety and stability.

[0049] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this invention are intended to be covered by the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A dump truck, characterized in that: The invention comprises an engine, a control system and a hydraulic cooling system, wherein the control system is connected to the engine, the hydraulic cooling system comprises a pump displacement control module (111), a plunger pump (112), an oil tank (113), a motor (131) and a fan (15), the control system is electrically connected to the pump displacement control module (111), the pump displacement control module (111) is electrically connected to the plunger pump (112), the pump displacement control module (111) can control the displacement of the plunger pump (112), the plunger pump (112) is communicated with the oil tank (113), the plunger pump (112) is communicated with the motor (131) through a pipeline, the output shaft of the motor (131) is connected to the fan (15), and the fan (15) is used to dissipate heat from the radiator of the dump truck; When the control system detects that the coolant temperature of the engine is lower than 0°C, the control system outputs a current range of 500mA to 550mA to the pump displacement control module (111), so that the plunger pump (112) is at zero displacement, the motor (131) has no speed output, and the hydraulic cooling system does not work; When the control system detects that the coolant temperature of the engine is between 0°C and 83°C, the control system outputs a current of 400mA to the pump displacement control module (111), causing the plunger pump (112) to output a first displacement value, and the motor (131) to output a rotation speed matching the first displacement value, so that the hydraulic heat dissipation system can meet the thermal balance performance at this time; When the control system detects that the coolant temperature of the engine is between 83°C and 93°C, the control system outputs a current range of 400mA to 120mA to the pump displacement control module (111), the displacement of the plunger pump (112) changes according to the current change of the pump displacement control module (111), and the hydraulic heat dissipation system maintains dynamic thermal balance according to the working conditions at this time; When the control system detects that the coolant temperature of the engine is greater than 93°C, the control system outputs a current of less than 120 mA to the pump displacement control module (111), the plunger pump (112) outputs a maximum displacement, and the motor (131) reaches a maximum speed; When the pump displacement control module (111) loses power, the plunger pump (112) outputs the maximum displacement, and the motor (131) rotates at the maximum speed.

2. The dump truck according to claim 1, wherein: When the control system detects that the hydraulic oil temperature in the oil tank (113) is greater than 80°C, the pump displacement control module (111) controls the plunger pump (112) to output a maximum displacement, and the motor (131) rotates at a maximum speed.

3. The dump truck according to claim 1, wherein: The hydraulic cooling system further includes an oil replenishing pump (114) and a filter (115). The oil replenishing pump (114) is connected between the oil tank (113) and the filter (115). The filter (115) is provided with a first oil outlet, and the first oil outlet is connected to the pump displacement control module (111). The oil in the oil tank (113) flows into the plunger pump (112) after passing through the oil replenishing pump (114), the first oil outlet and the pump displacement control module (111).

4. The hydraulic cooling system according to claim 3, characterized in that: The hydraulic cooling system further comprises an oil replenishment overflow valve (116), the filter (115) is provided with a second oil outlet, the oil replenishment overflow valve (116) is communicated with the second oil outlet, and the oil replenishment overflow valve (116) is used for replenishing oil and stabilizing pressure.

5. The dump truck according to claim 3, wherein: The plunger pump (112) is provided with a first oil circuit (11) and a second oil circuit (12), wherein the first oil circuit (11) is connected to a first oil port of the motor (131), and the second oil circuit (12) is connected to a second oil port of the motor (131), and the direction of rotation of the motor (131) is changed by supplying oil to the first oil circuit (11) or the second oil circuit (12); The hydraulic heat dissipation system further comprises a first pressure cut-off valve (117) and a second pressure cut-off valve (118), wherein the first pressure cut-off valve (117) is connected to the pump displacement control module (111) and the first oil circuit (11), and when the plunger pump (112) supplies oil to the first oil circuit (11) and the oil pressure of the first oil circuit (11) increases to the pressure value of the first pressure cut-off valve (117), the first pressure cut-off valve (117) opens, and the oil in the first oil circuit (11) overflows to the pump displacement control module (111), thereby reducing the displacement of the plunger pump (112); The second pressure cut-off valve (118) is connected to the pump displacement control module (111) and the second oil circuit (12). When the plunger pump (112) supplies oil to the second oil circuit (12) and the oil pressure in the second oil circuit (12) increases to the pressure value of the second pressure cut-off valve (118), the second pressure cut-off valve (118) opens, and the oil in the second oil circuit (12) overflows to the pump displacement control module (111), thereby reducing the displacement of the plunger pump (112).

6. The dump truck according to claim 5, wherein: The hydraulic cooling system comprises a first multifunctional valve (121) and a second multifunctional valve (122), wherein a first input end of the first multifunctional valve (121) is connected to the second oil port, a first output end of the first multifunctional valve (121) is connected to the first oil circuit (11), a second input end of the second multifunctional valve (122) is connected to the second oil port, and a second output end of the second multifunctional valve (122) is connected to the second oil circuit (12).

7. The dump truck according to claim 6, wherein: The first multifunctional valve (121) includes a first overflow valve (1211) and a first one-way valve (1212) arranged in parallel, and the second multifunctional valve (122) includes a second overflow valve (1221) and a second one-way valve (1222) arranged in parallel; when the plunger pump (112) supplies oil to the first oil circuit (11), the first overflow valve (1211) operates, and the second one-way valve (1222) opens and replenishes the oil in the second oil circuit (12); when the plunger pump (112) supplies oil to the second oil circuit (12), the second overflow valve (1221) operates, and the first one-way valve (1212) opens and replenishes the oil in the first oil circuit (11).

8. The dump truck according to claim 3, wherein: The hydraulic cooling system further includes a motor displacement control module (132), which is connected between the first oil circuit (11) and the second oil circuit (12). When the displacement of the plunger pump (112) is insufficient, the rotation speed of the motor (131) can be increased by reducing the displacement of the motor (131).

9. The dump truck according to claim 8, wherein: The hydraulic cooling system further comprises a flushing valve (133), wherein the flushing valve (133) is connected between the first oil circuit (11) and the second oil circuit (12), and the flushing valve (133) is used to cool the oil in the hydraulic cooling system.

10. A control method for the dump truck according to any one of claims 1 to 9, characterized in that: The control method includes: detecting the temperature of the engine coolant by means of the engine thermostat and feeding the data back to the control system, wherein the control system determines the temperature; When the control system determines that the engine coolant temperature is lower than 0°C, the control system outputs a current value of 500mA to 550mA to the pump displacement control module (111), the plunger pump (112) outputs an oil displacement of zero, and the motor (131) has no speed output; When the control system determines that the coolant temperature of the engine is between 0°C and 83°C, the control system changes the current value of the pump displacement control module (111) to 400mA, the plunger pump (112) outputs a first displacement value, and the motor (131) outputs a rotational speed matching the first displacement value; When the control system determines that the coolant temperature of the engine is between 83°C and 93°C, the control system proportionally changes the current value of the pump displacement control module (111) between 400 mA and 120 mA, and the displacement of the plunger pump (112) is proportionally changed; When the control system determines that the coolant temperature of the engine is above 93°C, the control system changes the current value of the pump displacement control module (111) to be less than 120mA, the plunger pump (112) outputs the maximum displacement value, and the motor (131) rotates at the maximum speed; When the pump displacement control module (111) loses power, the plunger pump (112) performs a large displacement output, causing the motor (131) to rotate at a maximum speed; During the operation of the dump truck, the control system detects and determines the temperature of the engine coolant in real time, so as to adjust the rotation speed of the motor (131) in real time according to different temperature ranges.

11. The method for controlling a dump truck according to claim 10, wherein: When the control system detects that the hydraulic oil temperature in the oil tank (113) is greater than 80°C, the pump displacement control module (111) controls the plunger pump (112) to output a maximum displacement, and the motor (131) reaches a maximum rotational speed.

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