Heat dissipation method and device of closed walking hydraulic system and static pressure bulldozer

Abstract

The invention relates to the technical field of engineering machinery, and discloses a heat dissipation method and device of a closed type walking hydraulic system and a static pressure bulldozer, the closed type walking hydraulic system is provided with an oil supplementing loop comprising an oil supplementing pump and a throttling valve, the oil supplementing pump is a variable pump, the throttling valve is used for controlling the flushing flow flowing into a walking motor shell from a main loop, and the static pressure bulldozer is connected with the main loop. Flowing of the flushing flow is driven by oil supplementing pressure established by the oil supplementing pump. The method comprises the following steps that the actual oil temperature of the hydraulic system is obtained; when the actual oil temperature is smaller than the first preset temperature, the throttling valve is controlled to be kept at the minimum opening degree; otherwise, the opening degree of the throttling valve is adjusted according to the difference value between the actual oil temperature and the heat dissipation starting temperature. The variable pump and the throttle valve are used for cooperatively controlling the flushing flow, and the oil temperature feedback dynamic adjustment is combined, so that the on-demand matching of the heat dissipation capability of the closed walking hydraulic system is realized.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to a heat dissipation method and device for a closed-loop hydraulic system and a static pressure bulldozer. Background Technology

[0002] For hydraulic bulldozers, hydraulic cooling primarily relies on the flow rate of the make-up pump, which includes three parts: internal system leakage, system flushing, and overflow from the make-up pump relief valve. The make-up pump is typically a fixed-displacement pump, and the flushing flow rate is generally also fixed. This results in relatively stable heat levels in the hydraulic oil at the radiator inlet. In extreme cases, if the hydraulic oil temperature exceeds the thermal equilibrium limit, the machine must be shut down and allowed to cool down. Furthermore, when a fixed-displacement pump is used as the make-up pump, the rate of temperature rise in the system oil cannot be controlled based on ambient temperature, making it impossible to guarantee the time it takes for the hydraulic system to reach its optimal operating temperature. Summary of the Invention

[0003] This invention provides a heat dissipation method, device, and static pressure bulldozer for a closed-loop hydraulic system, in order to solve the problem that existing closed-loop hydraulic systems cannot achieve the optimal operating temperature.

[0004] In a first aspect, the present invention provides a heat dissipation method for a closed-loop hydraulic system. The closed-loop hydraulic system is provided with a replenishment circuit for replenishing oil to the main circuit and providing a flushing oil source. The replenishment circuit includes a replenishment pump 11 and a throttle valve 25. The replenishment pump 11 is a variable pump, and the oil output from the outlet of the replenishment pump 11 constitutes the pressure source of the replenishment circuit. The throttle valve 25 is connected between the main circuit of the closed-loop hydraulic system and the travel motor housing to control the flushing flow rate flowing from the main circuit into the travel motor housing. The flow of the flushing flow rate is driven by the replenishment pressure established by the replenishment pump 11. The method includes the following steps: obtaining the actual oil temperature of the hydraulic system; when the actual oil temperature is less than a first preset temperature, controlling the throttle valve 25 to maintain a minimum opening; when the actual oil temperature is greater than or equal to the first preset temperature, adjusting the opening of the throttle valve 25 according to the difference between the actual oil temperature and the heat dissipation start temperature.

[0005] The heat dissipation method for the closed-loop hydraulic system provided by this invention uses a variable pump and a throttle valve 25 to control the flushing flow rate in coordination, and combines oil temperature feedback for dynamic adjustment, so as to achieve on-demand matching of the heat dissipation capacity of the closed-loop hydraulic system: reducing flushing in the low temperature stage to accelerate the temperature rise, and increasing flushing in the high temperature stage and linking the heat dissipation circuit to enhance cooling. This not only avoids the oil temperature runaway or frequent shutdown caused by the unadjustable heat dissipation of the quantitative oil replenishment system, but also significantly shortens the cold start heating time, and improves the system thermal efficiency, operation continuity and overall machine energy efficiency.

[0006] In some optional embodiments, the closed-loop hydraulic system is further provided with a control valve, which is located downstream of the oil drain port of the walking motor housing and has a first outlet connected to the radiator and a second outlet connected to the hydraulic oil tank 19. The method further includes: when the actual oil temperature is greater than or equal to a second preset temperature, controlling the control valve to open the first outlet, wherein the second preset temperature is less than the first preset temperature.

[0007] This embodiment achieves on-demand cooling of the hot oil in the travel motor housing by installing a control valve between the oil drain port and the radiator, and automatically opening the heat dissipation channel when the oil temperature reaches a second preset temperature (e.g., 60°C). During system cold starts or low-temperature operation, the control valve closes, and the drained oil returns directly to the oil tank, avoiding unnecessary heat loss and facilitating rapid temperature rise and maintenance of optimal operating temperature. When the oil temperature rises to the required heat dissipation threshold, the control valve opens, introducing the high-temperature oil into the radiator for cooling, effectively suppressing further temperature increases.

[0008] In some optional embodiments, the closed-loop hydraulic system also includes a heat dissipation circuit, which includes a radiator, a heat dissipation pump 14, a heat dissipation motor 15, and a heat dissipation fan driven by the heat dissipation motor 15; the oil drain port of the travel motor housing is connected to the inlet of the radiator; the heat dissipation pump 14 is used to drive the heat dissipation motor 15 to drive the heat dissipation fan to force air cooling of the radiator, and before the control valve opens the passage to the radiator, the system also includes the following steps: when the actual oil temperature is greater than or equal to a third preset temperature, the displacement of the heat dissipation pump 14 is adjusted, wherein the third preset temperature is less than the first preset temperature.

[0009] This implementation introduces an electro-proportional forced air cooling circuit consisting of a cooling pump 14, a cooling motor 15, and a cooling fan. By adjusting the cooling pump displacement in advance when the oil temperature reaches a third preset temperature (e.g., 70°C) to dynamically control the fan speed, continuous and precise matching of cooling capacity is achieved. Even before the control valve is fully open or only partially open, the air cooling intensity can be actively adjusted according to the system temperature rise trend, avoiding a sudden increase in oil temperature due to delayed heat dissipation. Simultaneously, since the third preset temperature (70°C) is lower than the first preset temperature for throttle valve activation (e.g., 75°C), the cooling fan can establish cooling conditions before a significant increase in flushing flow, forming a coordinated heat dissipation sequence of "air cooling first, then forced flushing," effectively improving heat exchange efficiency.

[0010] In some optional embodiments, the heat dissipation method of the closed-loop hydraulic system further includes the following steps: when the actual oil temperature is greater than or equal to a fourth preset temperature, the opening of the throttle valve 25 is controlled to reach its maximum, wherein the fourth preset temperature is greater than the first preset temperature; when the actual oil temperature is greater than or equal to a fifth preset temperature, the closed-loop hydraulic system is controlled to stop operating, wherein the fifth preset temperature is greater than the first preset temperature.

[0011] When the oil temperature reaches the fourth preset temperature, the throttle valve is adjusted to its maximum opening of 25 degrees, maximizing the flushing flow rate to remove heat from the travel motor and slowing down the temperature rise. If the heat dissipation measures are still insufficient to suppress the temperature rise, and the oil temperature continues to rise to the higher fifth preset temperature, the entire machine will be immediately shut down to prevent hydraulic components from experiencing seal failure, lubrication damage, or even burnout due to prolonged overheating. This two-stage high-temperature control strategy fully utilizes the system's own cooling potential while ensuring a safety baseline under extreme operating conditions, significantly improving the thermal reliability and fault tolerance of the closed-loop travel hydraulic system.

[0012] In some optional embodiments, the closed-loop hydraulic system further includes a pressure sensor, which is installed on the drain line of the housing of the travel motor or variable pump to detect the back pressure of the housing; the heat dissipation method of the closed-loop hydraulic system further includes the following steps: obtaining the actual back pressure of the drain line of the housing; when the actual back pressure is greater than a preset safety threshold, controlling the control valve to increase the opening of the second outlet and decrease the opening of the first outlet.

[0013] This implementation method introduces a pressure sensor. When the back pressure exceeds the safety threshold, it automatically bypasses part of the hot oil back to the oil tank to reduce the return oil resistance, effectively preventing seal damage, bearing lubrication failure, and other malfunctions caused by excessive back pressure.

[0014] Secondly, the present invention also provides a heat dissipation device for a closed-loop hydraulic system. The closed-loop hydraulic system is provided with a replenishment circuit for replenishing oil to the main circuit and providing a flushing oil source. The replenishment circuit includes a replenishment pump 11 and a throttle valve 25. The replenishment pump 11 is a variable pump, and the oil output from the outlet of the replenishment pump 11 constitutes the pressure source of the replenishment circuit. The throttle valve 25 is connected between the main circuit of the closed-loop hydraulic system and the walking motor housing, and is used to control the flushing flow from the main circuit into the walking motor housing. The flow of the flushing flow is driven by the replenishment pressure established by the replenishment pump 11. The device includes an acquisition module, a first processing module, and a second processing module. The acquisition module is used to acquire the actual oil temperature of the hydraulic system. The first processing module is used to control the throttle valve 25 to maintain a minimum opening when the actual oil temperature is less than a first preset temperature. The second processing module is used to adjust the opening of the throttle valve 25 according to the difference between the actual oil temperature and the heat dissipation start temperature when the actual oil temperature is greater than or equal to the first preset temperature.

[0015] Thirdly, the present invention provides an electronic device, comprising: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to perform the heat dissipation method of the closed-loop hydraulic system described in the first aspect or any corresponding embodiment thereof.

[0016] Fourthly, the present invention provides a computer-readable storage medium storing computer instructions for causing a computer to execute the cooling method of the closed-loop hydraulic system described in the first aspect or any corresponding embodiment thereof.

[0017] Fifthly, the present invention provides a computer program product, including computer instructions for causing a computer to execute the heat dissipation method of the closed-loop hydraulic system described in the first aspect or any corresponding embodiment. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the temperature range in the high-efficiency zone of a hydraulic system according to an embodiment of the present invention; Figure 2 This is a flowchart of a first control method for a closed-loop hydraulic system according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the internal throttle valve of the walking motor according to an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the relationship between the throttle valve current and flow rate according to an embodiment of the present invention; Figure 5 This is a schematic diagram of an example of a static pressure bulldozer hydraulic system according to an embodiment of the present invention; Figure 6 This is a flowchart of a second control method for a closed-loop hydraulic system according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the control logic of a closed-loop hydraulic system according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the control flow of a closed-loop hydraulic system according to an embodiment of the present invention; Figure 9 This is a structural block diagram of the closed-loop hydraulic system control device according to an embodiment of the present invention; Figure 10 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention; Among them, 1. Travel pump; 2. Travel pump; 3. Travel pump; 4. Travel pump; 5. Travel motor; 6. Travel motor; 7. Travel motor; 8. Travel motor; 9. Travel motor; 10. Travel motor; 11. Oil replenishment pump; 12. Control valve; 13. Control valve; 14. Cooling pump; 15. Cooling motor; 16. Engine speed sensor; 17. Hydraulic oil tank temperature sensor; 18. Controller; 19. Hydraulic oil tank. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] It is understood that before using the technical solutions disclosed in the various embodiments of the present invention, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in the present invention and their authorization should be obtained in accordance with relevant laws and regulations through appropriate means.

[0022] The static pressure bulldozer hydraulic system in this embodiment is a closed-loop hydraulic system with two pumps and three motors on one side. This is to ensure the hydraulic system always operates in its high-efficiency range. Figure 1 In the shaded area, taking commonly used VG46 hydraulic oil as an example, the hydraulic system temperature needs to be controlled between 45 and 70°C. Closed-loop hydraulic systems generate a lot of heat. Conventional closed-loop systems often use a fixed-displacement pump 11 and a constant-value flushing valve to forcibly displace some of the hot oil in the system to achieve heat dissipation. This method makes the system's heat dissipation flow rate unadjustable; when the temperature is too low, it cannot heat up quickly, resulting in energy waste; when the temperature is too high, it cannot increase the heat dissipation flow rate.

[0023] Based on this, this embodiment provides a first type of closed-loop hydraulic system. The first type of closed-loop hydraulic system is provided with a replenishment circuit for replenishing oil to the main circuit and providing a flushing oil source. The replenishment circuit includes a replenishment pump 11 and a throttle valve 25. The replenishment pump 11 is a variable pump. The oil output from the outlet of the replenishment pump 11 constitutes the pressure source of the replenishment circuit. The throttle valve 25 is connected between the main circuit of the closed-loop hydraulic system and the travel motor housing to control the flushing flow rate flowing from the main circuit into the travel motor housing. The flow of the flushing flow rate is driven by the replenishment pressure established by the replenishment pump 11.

[0024] Specifically, the replenishment circuit is used to replenish oil to the low-pressure side of the main circuit and provide a flushing oil source. The variable pump is a load-sensitive variable pump.

[0025] Figure 2 This is a flowchart of a first control method for a closed-loop hydraulic system according to an embodiment of the present invention, such as... Figure 2 As shown, the process includes the following steps: Step S201: Obtain the actual oil temperature of the hydraulic system.

[0026] Specifically, the actual oil temperature of the hydraulic system can be detected by the hydraulic oil tank temperature sensor 17.

[0027] Step S202: When the actual oil temperature is lower than the first preset temperature, control the throttle valve 25 to maintain the minimum opening.

[0028] For example, the first preset temperature can be 75°C.

[0029] This is because when the actual oil temperature is lower than the preset cooling start temperature, the closed-loop travel hydraulic system does not require cooling. At this time, the controller 18 does not output a control signal to the throttle valve 25, keeping it in a no-signal state. It relies on internal mechanical structures (such as a return spring) to maintain a small initial opening, thereby providing a basic flushing flow rate (e.g., about 10 L / min), which is only used to ensure normal oil replenishment and casing drain circulation in the closed loop, ensuring reliable system operation.

[0030] Meanwhile, the variable pump automatically adjusts to a smaller displacement based on the lower flow demand to avoid unnecessary energy output; the displacement of the cooling pump 14 is controlled to zero, the cooling motor 15 does not work, and the cooling fan stops rotating, thereby completely shutting down the cooling circuit.

[0031] Step S203: When the actual oil temperature is greater than or equal to the first preset temperature, adjust the opening of the throttle valve 25 according to the difference between the actual oil temperature and the heat dissipation start temperature.

[0032] In other words, when the variable pump system has no additional heat dissipation requirements, it only needs to maintain a basic flushing flow rate (e.g., 10 L / min), at which time the variable pump outputs a relatively small displacement. When the controller 18 increases the opening of the throttle valve 25 and increases the flushing flow rate (e.g., to 60 L / min) according to the oil temperature rise command, the flow demand on the low-pressure side of the system increases, and the variable pump responds by increasing the displacement to match the required flow rate. The structure of the throttle valve 25 is as follows: Figure 3 As shown.

[0033] In other words, when the actual oil temperature of the hydraulic system reaches or exceeds the preset cooling start temperature, it indicates that the closed-loop hydraulic system has generated a lot of heat and the active cooling mechanism needs to be activated. At this time, the controller 18 dynamically adjusts the cooling intensity based on the difference between the actual oil temperature and the cooling start temperature.

[0034] First, controller 18 increases the control current output to throttle valve 25. As the current increases, the valve core displacement of throttle valve 25 increases, and the flow area of ​​its throttle orifice increases accordingly. According to the throttle flow formula... , Indicates the flow rate of the throttle valve. Indicates the throttling coefficient. This indicates the flow area of ​​the throttling orifice. This indicates the pressure difference across the throttle valve. This indicates the density of the hydraulic oil; under conditions where the system pressure differential and oil properties are basically stable, the throttle valve flow rate... The flow rate increases significantly with the increase of the flow area A. The increased flushing flow rate is provided on demand by the load-sensitive variable oil replenishment pump 11. As the system's flow demand for low-pressure side oil replenishment and housing drain circuit increases, the load-sensitive variable oil replenishment pump 11 automatically increases its displacement to achieve on-demand oil supply, avoid overflow losses, and ensure efficient operation.

[0035] like Figure 4 As shown, the flow rate of the throttle valve 25 exhibits a non-linear growth trend with the increase of the control current. The flow rate increases rapidly in the initial stage, and tends to saturate as the current approaches its maximum value. This characteristic enables the controller 18 to achieve precise control of the flushing flow rate under different oil temperature conditions by accurately adjusting the input current, thereby optimizing the balance between heat dissipation efficiency and system energy consumption.

[0036] The heat dissipation method for the closed-loop hydraulic system provided in this embodiment uses a variable pump and a throttle valve 25 to control the flushing flow rate in coordination, and combines oil temperature feedback for dynamic adjustment. This achieves on-demand matching of the heat dissipation capacity of the closed-loop hydraulic system: reducing flushing in the low-temperature stage to accelerate the temperature rise, and increasing flushing in the high-temperature stage and linking the heat dissipation circuit to enhance cooling. This not only avoids the oil temperature runaway or frequent shutdowns caused by the unadjustable heat dissipation of the quantitative oil replenishment system, but also significantly shortens the cold start heating time, and improves the system's thermal efficiency, operational continuity and overall machine energy efficiency.

[0037] This embodiment also provides a second type of closed-loop hydraulic system for travel, which includes a replenishment circuit and a cooling circuit. The replenishment circuit replenishes oil to the main circuit and provides a flushing oil source. It includes a replenishment pump 11 and a throttle valve 25. The replenishment pump 11 is a variable displacement pump, and the oil output from its outlet constitutes the pressure source of the replenishment circuit. The throttle valve 25 is connected between the main circuit of the closed-loop hydraulic system and the travel motor housing to control the flushing flow rate from the main circuit into the travel motor housing. The flushing flow rate is driven by the replenishment pressure established by the replenishment pump 11. The cooling circuit includes a radiator, a cooling pump 14, a cooling motor 15, and a cooling fan driven by the cooling motor 15. The oil drain port of the travel motor housing is connected to the inlet of the radiator. The cooling pump 14 drives the cooling motor 15 to force-cool the radiator using the cooling fan. The closed-loop hydraulic system also includes a control valve located downstream of the oil drain port of the travel motor housing, with a first outlet connected to the radiator and a second outlet connected to the hydraulic oil tank 19.

[0038] Figure 5 This is a schematic diagram of an example of a static pressure bulldozer hydraulic system according to an embodiment of the present invention, as shown below. Figure 5 As shown, the system includes travel pumps 1, 2, 3, and 4, travel motors 5, 6, 7, 8, 9, and 10. The hydrostatic bulldozer hydraulic system also includes control valves 12 and 13, and an engine speed sensor 16. Control valve 12 is located on the oil line between the housing drain line of the left travel motor assembly (e.g., travel motors 5, 6, and 7) and the radiator, and is used to automatically adjust the flow rate to the radiator based on the oil temperature of the left hydraulic circuit. Control valve 13 is located on the oil line between the housing drain line of the right travel motor assembly (e.g., travel motors 8, 9, and 10) and the radiator, and is used to independently adjust the cooling flow rate of its corresponding branch based on the oil temperature of the right hydraulic circuit. By sensing the temperature and regulating the flow rate of the left and right hydraulic circuits respectively, the entire system can be maintained within the optimal operating temperature range under different load conditions. The engine speed sensor 16 is used to monitor the engine speed in real time, providing data support to the controller to optimize the working state of the replenishing pump and ensure the stable and efficient operation of the hydraulic system.

[0039] Figure 6 This is a flowchart of a second control method for a closed-loop hydraulic system according to an embodiment of the present invention, such as... Figure 6 and Figure 8 As shown, the process includes the following steps: Step S601: Obtain the actual oil temperature of the hydraulic system.

[0040] Step S602: When the actual oil temperature is greater than or equal to the second preset temperature, the control valve opens the first outlet, wherein the second preset temperature is less than the first preset temperature.

[0041] For example, the second preset temperature can be 60°C.

[0042] By installing a control valve between the oil drain port of the travel motor housing and the radiator, and automatically opening the heat dissipation channel when the oil temperature reaches a second preset temperature (e.g., 60℃), on-demand cooling of the hot oil in the housing is achieved. During system cold starts or low-temperature operating conditions, the control valve closes, and the drained oil returns directly to the oil tank, avoiding unnecessary heat loss and facilitating rapid temperature rise and maintenance of the optimal operating temperature. When the oil temperature rises to the required heat dissipation threshold, the control valve opens, introducing the high-temperature housing oil into the radiator for cooling, effectively suppressing the continuous rise in oil temperature.

[0043] Step S603: When the actual oil temperature is greater than or equal to the third preset temperature, start adjusting the displacement of the cooling pump 14, wherein the third preset temperature is less than the first preset temperature.

[0044] By introducing an electro-proportional forced air-cooling circuit consisting of a cooling pump 14, a cooling motor 15, and a cooling fan, and by dynamically controlling the fan speed by adjusting the cooling pump displacement in advance when the oil temperature reaches the third preset temperature (e.g., 70°C), continuous and precise matching of heat dissipation capacity is achieved. Even when the control valve is not yet open or only partially open, the air-cooling intensity can be actively adjusted according to the system temperature rise trend, avoiding a sudden rise in oil temperature due to delayed heat dissipation. Simultaneously, since the third preset temperature (70°C) is lower than the first preset temperature for throttle valve activation (e.g., 75°C), the cooling fan can establish cooling conditions before a significant increase in flushing flow, forming a coordinated heat dissipation sequence of "air cooling first, then forced flushing," effectively improving heat exchange efficiency.

[0045] Step S604: When the actual oil temperature is greater than or equal to the first preset temperature, adjust the opening of the throttle valve 25 according to the difference between the actual oil temperature and the heat dissipation start temperature.

[0046] For example, the first preset temperature can be 75°C.

[0047] Step S605: When the temperature reaches the fourth preset temperature, the throttle valve 25 is adjusted to the maximum opening and maintained, wherein the fourth preset temperature is greater than the first preset temperature.

[0048] For example, the fourth preset temperature can be 90℃.

[0049] Step S606: When the actual oil temperature is greater than or equal to the fifth preset temperature, control the closed-loop walking hydraulic system to stop running, wherein the fifth preset temperature is greater than the first preset temperature.

[0050] For example, the fifth preset temperature can be 95℃.

[0051] When the oil temperature reaches the fourth preset temperature, the throttle valve is adjusted to its maximum opening of 25 degrees, maximizing the flushing flow rate to remove heat from the travel motor and slowing down the temperature rise. If the heat dissipation measures are still insufficient to suppress the temperature rise, and the oil temperature continues to rise to the higher fifth preset temperature, the entire machine will be immediately shut down to prevent hydraulic components from experiencing seal failure, lubrication damage, or even burnout due to prolonged overheating. This two-stage high-temperature control strategy fully utilizes the system's own cooling potential while ensuring a safety baseline under extreme operating conditions, significantly improving the thermal reliability and fault tolerance of the closed-loop travel hydraulic system.

[0052] Furthermore, the closed-loop hydraulic system is also equipped with a pressure sensor. The pressure sensor is installed on the drain line of the travel motor or variable pump housing to detect the back pressure of the housing. The control method of the closed-loop hydraulic system also includes the following steps: obtaining the actual back pressure of the drain line of the housing; when the actual back pressure is greater than the preset safety threshold, controlling the control valve to increase the opening to the hydraulic oil tank 19 and decrease the opening to the radiator.

[0053] In other words, if the actual back pressure exceeds the safety threshold, it indicates that the current return oil resistance is too high, posing a risk of overpressure on the housing. At this time, controller 18 outputs a control signal to increase the opening of the control valve to the hydraulic oil tank 19 while simultaneously decreasing the opening to the radiator. This quickly reduces the housing return oil back pressure, ensuring the safe operation of the pump and motor. Although some hot oil does not pass through the radiator, the system prioritizes structural safety to avoid irreversible damage caused by excessive back pressure.

[0054] The pressure sensor introduced in this embodiment automatically bypasses part of the hot oil back to the oil tank to reduce the return oil resistance when the back pressure exceeds the safety threshold, effectively preventing seal damage, bearing lubrication failure and other faults caused by excessive back pressure.

[0055] To illustrate the heat dissipation method of the closed-loop hydraulic system in this embodiment more clearly, a specific example is given. For example... Figure 7As shown, when the system oil temperature is below T5, i.e., the second preset temperature, for example, 60℃, the cooling motor 15 operates at its minimum speed, and the cooling pump 14 operates at the given minimum displacement to maintain leakage compensation and basic oil circulation in the hydraulic system. At this time, the cooling fan is at its minimum speed. Simultaneously, the control valve closes the passage to the radiator, and all the oil drained from the travel motor housing returns to the hydraulic oil tank through the control valve. When the oil temperature reaches T5, the passage to the radiator in the control valve begins to open, introducing the oil drained from the travel motor housing into the radiator. Its opening degree automatically adjusts according to the set curve as the oil temperature rises, allowing the hot oil to begin participating in heat dissipation. When the oil temperature rises to T4, i.e., the third preset temperature, for example, 70℃, the controller begins to gradually increase the displacement of the cooling pump 14 according to the preset current-displacement curve, thereby increasing the speed of the cooling motor 15 and the fan airflow, actively and forcibly cooling the hot oil in the housing that has entered the radiator. When the oil temperature rises further to T3, the first preset temperature, for example, 75°C, the control valve's passage to the radiator fully opens and remains fully open. Simultaneously, the throttle valve 25 on the travel motor is energized, gradually increasing its opening according to the current-opening characteristic curve, thereby increasing the flushing flow rate. The output flow rate of the oil replenishment pump 11 increases accordingly. It should be noted that when the oil temperature is below T3, the throttle valve 25 is de-energized, maintaining a fixed minimum opening to ensure a continuous small amount of oil flushing the motor's interior, maintaining lubrication and leakage compensation. When the oil temperature reaches T2, the fourth preset temperature, for example, 90°C, the opening of the throttle valve 25 is adjusted to its maximum and maintained to provide maximum cooling capacity. If the oil temperature continues to rise to T1, the fifth preset temperature, for example, 95°C, it indicates that the system has exceeded its safe operating limits. Although all cooling measures have been activated, the temperature is still not effectively controlled. At this point, the vehicle shutdown protection must be triggered for troubleshooting.

[0056] It should be noted that during the entire operation, if the pressure in the drain line of the travel motor housing (i.e., the housing back pressure) exceeds 2 bar, the system will redirect all the drained oil from the housing to the hydraulic oil tank through the control valve to prevent excessive back pressure from damaging the hydraulic pump or motor. This pressure protection function is independent of the temperature control and fan control logic and has a higher priority.

[0057] This embodiment also provides a control device for a static pressure bulldozer, which is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0058] like Figure 9As shown, the heat dissipation device of the closed-loop hydraulic system includes an acquisition module 901, a first processing module 902, and a second processing module 903.

[0059] The acquisition module 901 is used to acquire the actual oil temperature of the hydraulic system.

[0060] The first processing module 902 is used to control the throttle valve 25 to maintain the minimum opening when the actual oil temperature is lower than the first preset temperature.

[0061] The second processing module 903 is used to adjust the opening of the throttle valve 25 according to the difference between the actual oil temperature and the heat dissipation start temperature when the actual oil temperature is greater than or equal to the first preset temperature.

[0062] In some optional embodiments, the cooling device of the closed-loop hydraulic system further includes a third processing module. The third processing module is used to control a control valve to open a passage to the radiator when the actual oil temperature is greater than or equal to a second preset temperature, wherein the second preset temperature is less than a first preset temperature. The control valve is located downstream of the drain port of the travel motor housing and has a first outlet connected to the radiator and a second outlet connected to the hydraulic oil tank 19.

[0063] In some optional embodiments, the closed-loop hydraulic system further includes a cooling circuit, which comprises a radiator, a cooling pump 14, a cooling motor 15, and a cooling fan driven by the cooling motor 15. The oil drain port of the travel motor housing is connected to the inlet of the radiator. The cooling pump 14 drives the cooling motor 15 to force the cooling fan to cool the radiator. The closed-loop hydraulic system also includes a fourth processing module, which, before the control valve opens the passage to the radiator, is further configured to: adjust the displacement of the cooling pump 14 when the actual oil temperature is greater than or equal to a third preset temperature, wherein the third preset temperature is less than a first preset temperature.

[0064] In some optional embodiments, the closed-loop hydraulic system further includes a fifth processing module. This fifth processing module is used to: control the opening of the throttle valve 25 to reach its maximum when the actual oil temperature is greater than or equal to a fourth preset temperature, wherein the fourth preset temperature is greater than the first preset temperature.

[0065] In some optional implementations, the closed-loop hydraulic system further includes a sixth processing module. This sixth processing module is used to: control the closed-loop hydraulic system to stop operating when the actual oil temperature is greater than or equal to a fifth preset temperature, wherein the fifth preset temperature is greater than a first preset temperature.

[0066] In some optional embodiments, the closed-loop hydraulic system further includes a pressure sensor located on the drain line of the travel motor or variable pump housing for detecting housing back pressure. The cooling system of the closed-loop hydraulic system also includes a seventh processing module. This seventh processing module is used to: acquire the actual back pressure of the drain line; and when the actual back pressure exceeds a preset safety threshold, control the control valve to increase the opening of the second outlet and decrease the opening of the first outlet.

[0067] The control device for a hydrostatic bulldozer provided in this embodiment of the invention can execute the control method for a hydrostatic bulldozer provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects for executing the method. Further functional descriptions of the various modules and units described above are the same as in the corresponding embodiments described above, and will not be repeated here.

[0068] Figure 10 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0069] The following is a detailed reference. Figure 10 This diagram illustrates a suitable structural schematic for implementing an electronic device according to embodiments of the present invention. The electronic device may include a processor (e.g., a central processing unit, graphics processor, etc.) 1001, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from memory 1008 into random access memory (RAM) 1003. The RAM 1003 also stores various programs and data required for the operation of the electronic device. The processor 1001, ROM 1002, and RAM 1003 are interconnected via a bus 1004. An input / output (I / O) interface 1005 is also connected to the bus 1004.

[0070] Typically, the following devices can be connected to the I / O interface 1005: input devices 1006 including, for example, a touchscreen, touchpad, keyboard, mouse, camera, microphone, accelerometer, gyroscope, etc.; output devices 1007 including, for example, a liquid crystal display (LCD), speaker, vibrator, etc.; memory devices 1008 including, for example, magnetic tape, hard disk, etc.; and communication devices 1009. Communication device 1009 allows electronic devices to exchange data via wireless or wired communication with other devices. Although Figure 10 Electronic devices with various devices are shown, but it should be understood that it is not required to implement or have all of the devices shown, and more or fewer devices may be implemented or have instead.

[0071] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a non-transitory computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device 1009, or installed from a memory 1008, or installed from a ROM 1002. When the computer program is executed by the processor 1001, it performs the functions defined in the heat dissipation method of the closed-loop hydraulic system according to embodiments of the present invention.

[0072] Figure 10 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0073] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that the computer, processor, microprocessor controller 18, or programmable hardware includes storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the heat dissipation method of the closed-loop hydraulic system shown in the above embodiments is implemented.

[0074] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0075] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A heat dissipation method for a closed-loop hydraulic system, characterized in that, The closed-loop hydraulic system is provided with a replenishment circuit for replenishing oil to the main circuit and providing a flushing oil source. The replenishment circuit includes a replenishment pump (11) and a throttle valve (25). The replenishment pump (11) is a variable pump. The oil output from the outlet of the replenishment pump (11) constitutes the pressure source of the replenishment circuit. The throttle valve (25) is connected between the main circuit of the closed-loop hydraulic system and the travel motor housing to control the flushing flow from the main circuit into the travel motor housing. The flow of the flushing flow is driven by the replenishment pressure established by the replenishment pump (11). The method includes: Obtain the actual oil temperature of the hydraulic system; When the actual oil temperature is less than the first preset temperature, the throttle valve (25) is controlled to maintain the minimum opening. When the actual oil temperature is greater than or equal to the first preset temperature, the opening of the throttle valve (25) is adjusted according to the difference between the actual oil temperature and the heat dissipation start temperature.

2. The method according to claim 1, characterized in that, The closed-loop hydraulic system also includes a control valve, which is located downstream of the drain port of the walking motor housing and has a first outlet connected to the radiator and a second outlet connected to the hydraulic oil tank (19). The method further includes: When the actual oil temperature is greater than or equal to the second preset temperature, the control valve is controlled to open the first outlet, wherein the second preset temperature is less than the first preset temperature.

3. The method according to claim 2, characterized in that, The closed-loop hydraulic system also includes a heat dissipation circuit, which comprises a radiator, a heat dissipation pump (14), a heat dissipation motor (15), and a heat dissipation fan driven by the heat dissipation motor (15). The oil drain port of the walking motor housing is connected to the inlet of the radiator. The heat dissipation pump (14) is used to drive the heat dissipation motor (15) to drive the heat dissipation fan to provide forced air cooling to the radiator. Before controlling the control valve to open the passage to the radiator, the system further includes: When the actual oil temperature is greater than or equal to the third preset temperature, the displacement of the cooling pump (14) is adjusted, wherein the third preset temperature is less than the first preset temperature.

4. The method according to claim 1, characterized in that, Also includes: When the actual oil temperature is greater than or equal to the fourth preset temperature, the opening of the throttle valve (25) is controlled to reach the maximum, wherein the fourth preset temperature is greater than the first preset temperature; When the actual oil temperature is greater than or equal to the fifth preset temperature, the closed-loop hydraulic system is controlled to stop operating, wherein the fifth preset temperature is greater than the first preset temperature.

5. The heat dissipation method for a closed-loop hydraulic system as described in claim 2, characterized in that, The closed-loop hydraulic system further includes a pressure sensor, which is installed on the drain line of the travel motor or variable pump housing to detect the housing back pressure; the method further includes: Obtain the actual back pressure of the housing drain line; When the actual back pressure is greater than a preset safety threshold, the control valve is controlled to increase the opening of the second outlet and decrease the opening of the first outlet.

6. A heat dissipation device for a closed-loop hydraulic system, characterized in that, The closed-loop hydraulic system is provided with a replenishment circuit for replenishing oil to the main circuit and providing flushing oil source. The replenishment circuit includes a replenishment pump (11) and a throttle valve (25). The replenishment pump (11) is a variable pump. The oil output from the outlet of the replenishment pump (11) constitutes the pressure source of the replenishment circuit. The throttle valve (25) is connected between the main circuit of the closed-loop hydraulic system and the travel motor housing to control the flushing flow from the main circuit into the travel motor housing. The flow of the flushing flow is driven by the replenishment pressure established by the replenishment pump (11). The device includes: The acquisition module is used to acquire the actual oil temperature of the hydraulic system; The first processing module is used to control the throttle valve (25) to maintain the minimum opening when the actual oil temperature is less than the first preset temperature; The second processing module is used to adjust the opening of the throttle valve (25) according to the difference between the actual oil temperature and the heat dissipation start temperature when the actual oil temperature is greater than or equal to the first preset temperature.

7. An electronic device, characterized in that, include: A memory and a processor are interconnected, the memory storing computer instructions, and the processor executing the computer instructions to perform the heat dissipation method of any one of claims 1 to 5 for a closed-loop hydraulic system.

8. A static pressure bulldozer, characterized in that, Includes the electronic device as described in claim 7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing a computer to execute the heat dissipation method of the closed-loop hydraulic system according to any one of claims 1 to 5.

10. A computer program product, characterized in that, Includes computer instructions for causing a computer to execute the heat dissipation method of the closed-loop hydraulic system according to any one of claims 1 to 5.

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