Heat management system for a bulldozer and a bulldozer

Abstract

The application discloses a bulldozer heat management system and a bulldozer. The two two-position two-way hydraulic pilot valves of the reversing valve group are connected in series to form a series branch, and the two ends of the series branch are respectively communicated with the output end of the flow regulating assembly and an oil supply tank. The first input end of the two-position four-way electromagnetic valve is communicated with the output end of the flow regulating assembly, the second input end is communicated with the second input end of the two-position four-way electromagnetic valve of another reversing valve group, the two output ends are respectively communicated with the first pressure end of the two two-position two-way hydraulic pilot valves, and the second pressure end of the two two-position two-way hydraulic pilot valves is communicated with the series branch. The two ends of the reversing oil way are respectively communicated with the reversing oil port and the pipeline between the two two-position two-way hydraulic pilot valves. The output shaft of the hydraulic motor is in transmission connection with the central rotating shaft of the temperature control fan. The temperature control fan can be driven to rotate forward, reverse or stop, the rotating speed of the temperature control fan can be adjusted, and energy waste can be avoided.

Description

Technical Field

[0001] This invention relates to the field of bulldozer technology, and more particularly to a thermal management system for bulldozers and a bulldozer. Background Technology

[0002] A bulldozer is an earthmoving machine capable of excavating, transporting, and disposing of soil and rock. During normal operation, bulldozers require cooling for various systems, including engine coolant, engine intake air, transmission hydraulic fluid, working hydraulic fluid, and air conditioning cooler. Therefore, a cooling fan combined with a radiator is typically used to dissipate heat from these systems. Cooling fans are mainly classified into three types based on their drive mechanism: mechanical fans directly driven by the engine, electronic fans, and temperature-controlled fans. Temperature-controlled fans are the most popular choice for bulldozers due to their flexible placement, adjustable speed, and energy-saving advantages.

[0003] In existing technologies, cooling fan systems formed by temperature-controlled fans are mainly divided into fixed-rate systems and variable-rate systems. For variable-rate systems, they mainly consist of a temperature-controlled fan, a variable displacement piston pump, a two-position solenoid valve, and a motor. The output flow rate is adjusted by the variable displacement piston pump to control the speed of the temperature-controlled fan, and the two-position solenoid valve controls the reversal of the temperature-controlled fan to achieve the reverse cleaning function. However, they all have a minimum speed requirement for the temperature-controlled fan, which will cause energy waste in the system when the bulldozer is started, when insulation is needed in extremely cold conditions, and when the temperature rises rapidly. Summary of the Invention

[0004] The purpose of this invention is to provide a thermal management system and a bulldozer to solve the problem that although the existing temperature-controlled fan cooling fan system can control the speed of the temperature-controlled fan and realize the reverse cleaning function, it basically has a minimum speed requirement for the temperature-controlled fan. This causes energy waste in the system when the bulldozer is started, when heat preservation is needed in extremely cold conditions, and when the temperature rises rapidly.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A thermal management system for bulldozers includes:

[0007] The hydraulic system includes an oil supply tank, a flow regulation component, and a reversing component. The oil supply tank supplies hydraulic oil to the flow regulation component, and the flow regulation component is used to regulate the flow rate of hydraulic oil delivered to the reversing component per unit time.

[0008] The reversing assembly includes two parallel reversing valve groups, each including a two-position four-way solenoid valve and two two-position two-way hydraulic pilot valves. The two two-position two-way hydraulic pilot valves are connected in series to form a series branch, and the two ends of the series branch are respectively connected to the output end of the flow regulating assembly and the oil supply tank. The first input end of the two-position four-way solenoid valve is also connected to the output end of the flow regulating assembly, and the second input end of the two-position four-way solenoid valve is connected to the second input end of the two-position four-way solenoid valve of the other reversing valve group. The two output ends of the two-position four-way solenoid valve are respectively connected to the first pressure ends of the two two-position two-way hydraulic pilot valves, and the second pressure ends of the two two-position two-way hydraulic pilot valves are both connected to the series branch. The two-position two-way hydraulic pilot valves can connect or disconnect the series branch.

[0009] Two reversing oil circuits are provided, and the two reversing oil circuits are configured one-to-one with the two reversing valve groups. The reversing oil circuit includes a first connecting end and a second connecting end. The second connecting end is connected to the pipeline between the two two-position two-way hydraulic pilot valves on the series branch.

[0010] The hydraulic motor and the temperature-controlled fan are provided. The hydraulic motor has two reversing oil ports, which are respectively set and connected to the first connecting ends of the two reversing oil circuits. The output shaft of the hydraulic motor is connected to the central rotating shaft of the temperature-controlled fan.

[0011] Preferably, the thermal management system for the bulldozer also includes a plurality of temperature sensors electrically connected to the controller. The plurality of temperature sensors include at least an ambient temperature sensor located outside the cab of the bulldozer, a water temperature sensor located in the engine circulating water circuit of the bulldozer, an intake air temperature sensor located in the engine air intake of the bulldozer, and an oil temperature sensor located in the transmission system oil circuit of the bulldozer.

[0012] The flow regulating component and the two-position four-way solenoid valve are also electrically connected to the controller.

[0013] Preferably, the second pressure end of the two-position two-way hydraulic pilot valve is provided with two pressure oil circuits, one end of each pressure oil circuit is connected to the second pressure end, and the other end of each pressure oil circuit is connected to the series branch on both sides of the two-position two-way hydraulic pilot valve.

[0014] Preferably, the thermal management system for bulldozers further includes a safety oil circuit and a safety valve. One end of the safety oil circuit is connected to the pipeline connecting the second input ends of the two two-position four-way solenoid valves, and the other end is connected to the pipeline connecting the series branch to the oil supply tank.

[0015] The third input terminal and the third pressure terminal of the safety valve are both connected to one of the series branches, and the output terminal of the safety valve is connected to the safety oil circuit.

[0016] Preferably, a first throttle valve is provided on each of the pipelines connecting the two output ends of the two two-position two-way hydraulic pilot valves to the first pressure ends of the two two-position two-way hydraulic pilot valves.

[0017] Preferably, the flow regulating assembly includes a variable pump body, a swashplate, a first hydraulic cylinder, and a second hydraulic cylinder. The pump input end of the variable pump body is connected to the oil supply tank. The first pump output end of the variable pump body is connected to both the series branch and the first input end of the two-position four-way solenoid valve. The second pump output end of the variable pump body is connected to the first hydraulic cylinder. The third pump output end of the variable pump body is connected to the second hydraulic cylinder. The swashplate is connected to both the hydraulic rod of the first hydraulic cylinder and the hydraulic rod of the second hydraulic cylinder.

[0018] Preferably, the flow regulating component further includes a regulating oil circuit, a pressure shut-off valve, and an inverse proportional solenoid valve. One end of the regulating oil circuit is connected to the output end of the third pump, and the other end of the regulating oil circuit is provided with a first regulating branch, a second regulating branch, and a third regulating branch. The first regulating branch is connected to a fourth pressure end of the pressure shut-off valve, the second regulating branch is connected to the fourth input end of the pressure shut-off valve, the output end of the pressure shut-off valve is connected to the second hydraulic cylinder, and the third connecting end of the pressure shut-off valve is connected to the oil supply tank.

[0019] The third regulating branch is connected to the other fourth pressure end of the pressure shut-off valve, and is also connected to the fifth input end and the fifth pressure end of the inverse proportional solenoid valve. The output end of the inverse proportional solenoid valve is connected to the oil supply tank.

[0020] Preferably, the thermal management system for bulldozers further includes an oil return assembly, which includes an oil return line, one end of which is connected to the series branch, and the other end of which is connected to the oil supply tank.

[0021] Preferably, the oil return assembly further includes a radiator, a two-position two-way solenoid directional valve, a first electrically controlled check valve, and a first oil return branch and a second oil return branch connected in parallel on the oil return line. The two-position two-way solenoid directional valve and the radiator are connected in series in the first oil return branch, and the first electrically controlled check valve is located in the second oil return branch.

[0022] Bulldozer, including the aforementioned bulldozer thermal management system.

[0023] The beneficial effects of this invention are:

[0024] This invention provides a thermal management system for bulldozers, comprising an oil supply tank, a flow regulation component, a reversing component, two reversing oil circuits, a hydraulic motor, and a temperature-controlled fan. When the temperature-controlled fan is required for heat dissipation, the flow regulation component delivers hydraulic oil from the oil supply tank to the reversing component at the required flow rate. A series branch is formed by connecting two two-position, two-way hydraulic pilot valves in series, with both ends of the series branch connected to the output of the flow regulation component and the oil supply tank, respectively. The first input of a two-position, four-way solenoid valve is connected to the output of the flow regulation component, and the second input of the two-position, four-way solenoid valve is connected to the second input of a two-position, four-way solenoid valve in another reversing valve group. The two outputs of the two-position, four-way solenoid valve are connected to the first pressure ends of the two two-position, two-way hydraulic pilot valves, respectively. The hydraulic oil supplied to the reversing assembly is divided into four separate paths. Specifically, when both two two-position four-way solenoid valves are de-energized, one path of hydraulic oil enters the first pressure end of a two-position two-way hydraulic pilot valve located on the left-side series branch near the oil supply tank; the second path enters the input end of a two-position two-way hydraulic pilot valve located on the left-side series branch near the oil supply tank; the third path enters the input end of a two-position two-way hydraulic pilot valve located on the right-side series branch near the oil supply tank; and the fourth path enters a two-position two-way hydraulic pilot valve located on the right-side series branch away from the oil supply tank. The first pressure end of the pilot valve is connected to the second pressure ends of the two two-position two-way hydraulic pilot valves on the right-hand series branch, which are also connected to the series branch. This connects the input and output ends of the two-position two-way hydraulic pilot valve located near the oil supply tank on the right-hand series branch. Hydraulic oil flows out from the output end of the two-position two-way hydraulic pilot valve near the oil supply tank on the right-hand series branch and then flows through one of the second connecting ends of the right-hand reversing oil circuit to one of the reversing ports of the hydraulic motor. This drives the hydraulic motor to rotate at a certain speed, thereby driving the temperature control fan to rotate at a certain speed in a clockwise direction. The hydraulic oil then... The oil flows out from the other reversing port of the pressure motor and flows from the reversing oil circuit on the left into the pipeline between the two two-position two-way hydraulic pilot valves in the series branch on the left. Since the second pressure end of the two two-position two-way hydraulic pilot valves in the series branch on the left is connected to the series branch, the input end and output end of the two-position two-way hydraulic pilot valve located on the series branch on the left, which is far from the oil supply tank, are connected. The hydraulic oil flows out from the output end of the two-position two-way hydraulic pilot valve located on the series branch on the left, which is far from the oil supply tank, and then flows back to the oil supply tank, so as to drive the temperature control fan to rotate in the first clockwise direction at the first speed.

[0025] When both two two-position four-way solenoid valves are energized, one path of hydraulic oil enters the first pressure end of a two-position two-way hydraulic pilot valve located on the left-hand series branch, away from the oil supply tank. The second path enters the input end of a two-position two-way hydraulic pilot valve located on the left-hand series branch, near the oil supply tank. The third path enters the input end of a two-position two-way hydraulic pilot valve located on the right-hand series branch, also near the oil supply tank. The fourth path enters the first pressure end of a two-position two-way hydraulic pilot valve located on the right-hand series branch, also near the oil supply tank. Since the second pressure ends of both two-position two-way hydraulic pilot valves on the left-hand series branch are connected to the series branch, the input and output ends of the two-position two-way hydraulic pilot valve located on the left-hand series branch near the oil supply tank are connected. Hydraulic oil flows from the output end of the two-position two-way hydraulic pilot valve located on the left-hand series branch near the oil supply tank. After flowing out from the outlet, the oil flows from one of the second connecting ends of the reversing oil circuit on the left to one of the reversing oil ports of the hydraulic motor, driving the hydraulic motor to rotate at a certain speed, thereby driving the temperature control fan to rotate at a certain speed in the second clockwise direction. Then, the oil flows out from the other reversing oil port of the hydraulic motor and flows into the pipeline between the two two-position two-way hydraulic pilot valves of the series branch on the right from the reversing oil circuit on the right. Since the second pressure ends of the two two-position two-way hydraulic pilot valves on the series branch on the right are connected to the series branch, the input end and output end of the two-position two-way hydraulic pilot valve located on the series branch on the right, which is far from the oil supply tank, are connected. The hydraulic oil flows out from the output end of the two-position two-way hydraulic pilot valve located on the series branch on the right, which is far from the oil supply tank, and then flows back to the oil supply tank, so as to drive the temperature control fan to rotate at the second speed in the second clockwise direction. It can be understood that the first clockwise direction is opposite to the second clockwise direction.

[0026] When one of the two two-position four-way solenoid valves is energized and the other is de-energized, taking the example of the left-side two-position four-way solenoid valve being de-energized and the right-side two-position four-way solenoid valve being energized, one path of hydraulic oil enters the first pressure end of a two-position two-way hydraulic pilot valve located near the oil supply tank on the left-side series branch; the second path of hydraulic oil enters the input end of a two-position two-way hydraulic pilot valve located near the oil supply tank on the left-side series branch; the third path of hydraulic oil enters the input end of a two-position two-way hydraulic pilot valve located near the oil supply tank on the right-side series branch; and the fourth path of hydraulic oil enters the first pressure end of a two-position two-way hydraulic pilot valve located near the oil supply tank on the right-side series branch. This prevents hydraulic oil from being delivered to the reversing port of the hydraulic motor, and the temperature control fan stops rotating. When the left-side two-position four-way solenoid valve is energized and the right-side two-position four-way solenoid valve is de-energized, the temperature control fan also stops rotating. It can be understood that the flow regulation component can also be controlled to stop supplying hydraulic oil to the reversing component to control the temperature control fan to stop rotating.

[0027] Therefore, this bulldozer thermal management system can control the output shaft of the hydraulic motor driven by the reversing component to rotate forward, reverse, or stop rotating according to actual heat dissipation needs, thereby driving the temperature control fan to rotate forward, reverse, or stop rotating. Secondly, the flow regulation component of this bulldozer thermal management system can control the flow rate of hydraulic oil delivered to the reversing component according to actual heat dissipation needs, enabling real-time adjustment of the output speed of the hydraulic motor's output shaft, thereby enabling real-time adjustment of the temperature control fan's speed. In summary, this not only improves the performance of the bulldozer thermal management system but also allows the temperature control fan to stop rotating or rotate at a lower speed during bulldozer startup, and / or when heat preservation is required in extremely cold conditions, and / or during rapid heating, avoiding energy waste.

[0028] The present invention also provides a bulldozer that, by adopting the above-mentioned bulldozer thermal management system, can control the temperature control fan to rotate forward, reverse, or stop rotating according to actual heat dissipation needs, and can also adjust the speed of the temperature control fan in real time, thereby improving the working performance of the bulldozer. It also enables the temperature control fan to stop rotating or rotate at a lower speed when the bulldozer is first started, and / or when heat preservation is required in extremely cold conditions, and / or when rapid heating is required, thus avoiding energy waste. Attached Figure Description

[0029] Figure 1 This is a partial schematic diagram of a thermal management system for bulldozers provided in a specific embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of a thermal management system for bulldozers provided in a specific embodiment of the present invention.

[0031] In the picture:

[0032] 1. Fuel tank;

[0033] 2. Flow regulating assembly; 21. Variable pump body; 22. Swashplate; 23. First hydraulic cylinder; 24. Second hydraulic cylinder; 25. Regulating oil circuit; 251. First regulating branch; 252. Second regulating branch; 253. Third regulating branch; 26. Pressure shut-off valve; 27. Inverse proportional solenoid valve; 281. Circulating oil circuit; 282. Second throttle valve; 29. ​​Third throttle valve; 30. Fourth throttle valve;

[0034] 3. Reversing valve assembly; 31. Two-position four-way solenoid valve; 32. Two-position two-way hydraulic pilot valve; 321. First pressure end; 322. Pressure oil circuit; 33. Series branch; 34. First throttle valve;

[0035] 4. Reversing oil circuit;

[0036] 5. Hydraulic motor; 51. Reversing oil port;

[0037] 6. Temperature-controlled fan;

[0038] 71. Safety oil circuit; 72. Safety valve;

[0039] 8. Oil return assembly; 81. Oil return circuit; 811. First oil return branch; 812. Second oil return branch; 82. Radiator; 83. Two-position two-way solenoid directional valve; 84. First electrically controlled check valve; 85. Oil return filter; 86. Third electrically controlled check valve;

[0040] 91. Buffer oil circuit; 92. Second electrically controlled check valve;

[0041] 101. Oil suction filter;

[0042] 11. First drain oil passage;

[0043] 12. Second oil drain line. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0045] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0047] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0048] This invention provides a thermal management system for bulldozers, such as... Figure 1 As shown, the thermal management system for the bulldozer includes an oil supply tank 1, a flow regulating component 2, a reversing component, two reversing oil circuits 4, a hydraulic motor 5, and a temperature control fan 6. The oil supply tank 1 supplies hydraulic oil to the flow regulating component 2, which regulates the flow rate of hydraulic oil delivered to the reversing component per unit time. The reversing component includes two parallel reversing valve groups 3, each comprising a two-position four-way solenoid valve 31 and two two-position two-way hydraulic pilot valves 32. The two two-position two-way hydraulic pilot valves 32 are connected in series to form a series branch 33, with both ends of the series branch 33 connected to the output end of the flow regulating component 2 and the oil supply tank 1, respectively. The first input end of the two-position four-way solenoid valve 31 is also connected to the output end of the flow regulating component 2, and the second input end of the two-position four-way solenoid valve 31 is connected to the second input end of the two-position four-way solenoid valve 31 of the other reversing valve group 3. The two output ends of 31 are respectively connected to the first pressure ends 321 of the two two-position two-way hydraulic pilot valves 32. The second pressure ends of the two two-position two-way hydraulic pilot valves 32 are both connected to the series branch 33. The two-position two-way hydraulic pilot valves 32 can connect or disconnect the series branch 33. The two reversing oil circuits 4 are set one-to-one with the two reversing valve groups 3. The reversing oil circuit 4 includes a first connecting end and a second connecting end. The second connecting end is connected to the pipeline between the two two-position two-way hydraulic pilot valves 32 on the series branch 33. The hydraulic motor 5 is provided with two reversing oil ports 51. The two reversing oil ports 51 are set one-to-one with the first connecting ends of the two reversing oil circuits 4 and are connected. The output shaft of the hydraulic motor 5 is connected to the central rotating shaft of the temperature control fan 6.

[0049] like Figure 1As shown, when the temperature-controlled fan 6 needs to rotate for heat dissipation, the flow regulating component 2 delivers the hydraulic oil in the oil supply tank 1 to the reversing component at the required flow rate. This is achieved by connecting two two-position two-way hydraulic pilot valves 32 in series to form a series branch 33. The two ends of the series branch 33 are connected to the output end of the flow regulating component 2 and the oil supply tank 1, respectively. The first input end of the two-position four-way solenoid valve 31 is connected to the output end of the flow regulating component 2, and the second input end of the two-position four-way solenoid valve 31 is connected to the second input end of the two-position four-way solenoid valve 31 of another reversing valve group 3. The two output ends of the two-position four-way solenoid valve 31 are connected to the first pressure ends 321 of the two two-position two-way hydraulic pilot valves 32, thus dividing the hydraulic oil delivered to the reversing component into four separate paths. Specifically, when both two two-position four-way solenoid valves 31 are de-energized, the hydraulic oil flows along… Figure 1 In the left and right directions, one path of hydraulic oil enters the first pressure end 321 of a two-position two-way hydraulic pilot valve 32 located on the left side of the series branch 33 near the oil supply tank 1; the second path of hydraulic oil enters the input end of a two-position two-way hydraulic pilot valve 32 located on the left side of the series branch 33 near the oil supply tank 1; the third path of hydraulic oil enters the input end of a two-position two-way hydraulic pilot valve 32 located on the right side of the series branch 33 near the oil supply tank 1; and the fourth path of hydraulic oil enters the first pressure end 321 of a two-position two-way hydraulic pilot valve 32 located on the right side of the series branch 33 away from the oil supply tank 1. Since the second pressure ends of the two two-position two-way hydraulic pilot valves 32 on the right side of the series branch 33 are both connected to the series branch 33, the input and output ends of the two-position two-way hydraulic pilot valve 32 located on the right side of the series branch 33 near the oil supply tank 1 are connected. The hydraulic oil flows from the first pressure end 321 of the two-position two-way hydraulic pilot valve 32 located on the right side of the series branch 33 near the oil supply tank 1. After the output of the two-position two-way hydraulic pilot valve 32 flows out, it flows through one of the second connecting ends of the right-side reversing oil circuit 4 to one of the reversing oil ports 51 of the hydraulic motor 5, driving the hydraulic motor 5 to rotate at a certain speed, thereby driving the temperature control fan 6 to rotate at a certain speed in the first clockwise direction. Then, it flows out from the other reversing oil port 51 of the hydraulic motor 5 and flows into the pipeline between the two two-position two-way hydraulic pilot valves 32 of the left-side series branch 33 through the left-side reversing oil circuit 4. Since the second pressure ends of the two two-position two-way hydraulic pilot valves 32 on the left-side series branch 33 are connected to the series branch 33, the input and output ends of the two-position two-way hydraulic pilot valve 32 located on the left-side series branch 33 away from the oil supply tank 1 are connected. The hydraulic oil flows out from the output end of the two-position two-way hydraulic pilot valve 32 located on the left-side series branch 33 away from the oil supply tank 1 and then flows back to the oil supply tank 1, so as to drive the temperature control fan 6 to rotate at the first speed in the first clockwise direction. Specifically, along Figure 1 and Figure 2 In the vertical direction, the upper two-position two-way hydraulic pilot valve 32 is farther away from the oil supply tank 1 than the lower two-position two-way hydraulic pilot valve 32.

[0050] like Figure 1 As shown, when both two two-position four-way solenoid valves 31 are energized, along... Figure 1 In the left-right direction, one path of hydraulic oil enters the first pressure end 321 of a two-position two-way hydraulic pilot valve 32 on the left-side series branch 33, away from the oil supply tank 1. The second path enters the input end of a two-position two-way hydraulic pilot valve 32 on the left-side series branch 33, near the oil supply tank 1. The third path enters the input end of a two-position two-way hydraulic pilot valve 32 on the right-side series branch 33, near the oil supply tank 1. The fourth path enters the first pressure end 321 of a two-position two-way hydraulic pilot valve 32 on the right-side series branch 33, near the oil supply tank 1. Since the second pressure ends of the two two-position two-way hydraulic pilot valves 32 on the left-side series branch 33 are connected to the series branch 33, the input and output ends of the two-position two-way hydraulic pilot valve 32 on the left-side series branch 33, near the oil supply tank 1, are connected. Hydraulic oil flows from the input end of the two-position two-way hydraulic pilot valve 32 on the left-side series branch 33, near the oil supply tank 1. After flowing out from the outlet, it flows from one of the second connecting ends of the left-side reversing oil circuit 4 to one of the reversing oil ports 51 of the hydraulic motor 5, driving the hydraulic motor 5 to rotate at a certain speed, thereby driving the temperature control fan 6 to rotate at a certain speed in the second clockwise direction. Then it flows out from the other reversing oil port 51 of the hydraulic motor 5 and flows from the right-side reversing oil circuit 4 into the pipeline between the two two-position two-way hydraulic pilot valves 32 of the right-side series branch 33. The second pressure end of 2 is connected to the series branch 33, so that the input end and output end of a two-position two-way hydraulic pilot valve 32 on the right side of the series branch 33, which is far away from the oil supply tank 1, are connected. The hydraulic oil flows out from the output end of the two-position two-way hydraulic pilot valve 32 on the right side of the series branch 33, which is far away from the oil supply tank 1, and then flows back to the oil supply tank 1, so as to drive the temperature control fan 6 to rotate at the second speed in the second clockwise direction. It can be understood that the first clockwise direction is opposite to the second clockwise direction.

[0051] like Figure 1 As shown, when one of the two two-position four-way solenoid valves 31 is energized and the other is de-energized, along... Figure 1Taking the left and right directions as an example, with the left-side two-position four-way solenoid valve 31 not energized and the right-side two-position four-way solenoid valve 31 energized, one path of hydraulic oil enters the first pressure end 321 of a two-position two-way hydraulic pilot valve 32 near the oil supply tank 1 on the left-side series branch 33; the second path of hydraulic oil enters the input end of a two-position two-way hydraulic pilot valve 32 near the oil supply tank 1 on the left-side series branch 33; and the third path of hydraulic oil enters a two-position two-way hydraulic pilot valve 32 near the oil supply tank 1 on the right-side series branch 33. At the input end of 2, the fourth hydraulic oil enters the first pressure end 321 of a two-position two-way hydraulic pilot valve 32 located on the right side of the series branch 33 near the oil supply tank 1, so that the hydraulic oil cannot be delivered to the reversing port 51 of the hydraulic motor 5, and the temperature control fan 6 stops rotating at this time; when the two-position four-way solenoid valve 31 located on the left is energized and the two-position four-way solenoid valve 31 located on the right is de-energized, the temperature control fan 6 also stops rotating; it can be understood that the flow regulating component 2 can also be controlled to stop delivering hydraulic oil to the reversing component to control the temperature control fan 6 to stop rotating.

[0052] Therefore, the bulldozer thermal management system can control the output shaft of the hydraulic motor 5 to rotate forward, reverse, or stop rotating according to actual heat dissipation needs, thereby driving the temperature control fan 6 to rotate forward, reverse, or stop rotating. Secondly, the flow regulation component 2 of the bulldozer thermal management system can control the flow rate of hydraulic oil supplied to the reversing component according to actual heat dissipation needs, enabling real-time adjustment of the output speed of the hydraulic motor 5's output shaft, thereby real-time adjustment of the temperature control fan 6's speed. In summary, this not only improves the performance of the bulldozer thermal management system but also allows the temperature control fan 6 to stop rotating or rotate at a lower speed when the bulldozer is first started, and / or in extremely cold conditions requiring heat preservation, and / or during rapid heating, thus avoiding energy waste.

[0053] The bulldozer thermal management system also includes multiple temperature sensors electrically connected to the controller. These sensors include, at least, an ambient temperature sensor located outside the bulldozer's cab, a water temperature sensor located on the engine's cooling water circuit, an intake air temperature sensor located at the engine's air intake, and an oil temperature sensor located on the transmission system's oil circuit. The flow regulating component 2 and the two-position four-way solenoid valve 31 are also electrically connected to the controller. It is understood that the controller can control the flow regulating component 2 to adjust the flow rate of the hydraulic oil delivered to the reversing assembly based on the ambient temperature, the water temperature on the engine's cooling water circuit, the intake air temperature at the engine's air intake, and the oil temperature on the transmission system's oil circuit. It also controls the rotation direction of the two two-position four-way solenoid valves 31 that drive the temperature-controlled fan 6.

[0054] Specifically, when the water temperature in the engine's circulating water circuit is lower than the minimum set water temperature, the air intake temperature at the engine's air intake port is lower than the minimum set air intake temperature, and the oil temperature in the transmission system's oil circuit is lower than the minimum set oil temperature, the controller controls one of the two two-position four-way solenoid valves 31 to be energized and the other to be de-energized, so that the hydraulic motor 5's reversing oil port 51 does not receive oil, and the temperature control fan 6 stops rotating.

[0055] Specifically, when the ambient temperature is lower than the minimum set ambient temperature, the controller can control the flow regulating component 2 to stop supplying hydraulic oil to the reversing component, thereby controlling the temperature control fan 6 to stop rotating.

[0056] More specifically, when the ambient temperature is lower than the minimum set ambient temperature, and / or the water temperature in the engine's circulating water circuit is lower than the minimum set water temperature, and / or the air intake temperature at the engine's air intake is lower than the minimum set air intake temperature, and / or the oil temperature in the transmission system's oil circuit is lower than the minimum set oil temperature, the controller can adaptively readjust the minimum set ambient temperature based on the ambient temperature, the minimum set water temperature based on the engine's circulating water circuit, the minimum set air intake temperature based on the engine's air intake, and the minimum set oil temperature based on the transmission system's oil circuit. This enables cyclic self-learning control, further improving the performance of the bulldozer's thermal management system.

[0057] Specifically, when the ambient temperature is greater than the maximum set ambient temperature, and / or the water temperature in the engine circulating water circuit is greater than the maximum set water temperature, and / or the intake air temperature in the engine air intake port is greater than the maximum set intake air temperature, and / or the oil temperature in the transmission system oil circuit is greater than the maximum set oil temperature, the controller controls the two two-position four-way solenoid valves 31 to be energized or de-energized, so that the temperature control fan 6 rotates regularly at the set speed.

[0058] More specifically, when the ambient temperature exceeds the maximum set ambient temperature, and / or the water temperature in the engine's circulating water circuit exceeds the maximum set water temperature, and / or the air intake temperature at the engine's air intake exceeds the maximum set air intake temperature, and / or the oil temperature in the transmission system's oil circuit exceeds the maximum set oil temperature, the controller can adaptively readjust the maximum set ambient temperature based on the ambient temperature, the maximum set water temperature based on the engine's circulating water circuit, the maximum set air intake temperature based on the engine's air intake, and the maximum set oil temperature based on the transmission system's oil circuit. This enables cyclic self-learning control, further improving the performance of the bulldozer's thermal management system.

[0059] Among them, such as Figure 1 and Figure 2As shown, the second pressure end of the two-position two-way hydraulic pilot valve 32 is provided with two pressure oil passages 322. One end of each pressure oil passage 322 is connected to the second pressure end, and the other end of each pressure oil passage 322 is connected to the series branch 33 on both sides of the two-position two-way hydraulic pilot valve 32. Specifically, taking the two two-position four-way solenoid valves 31 as an example when neither is energized, along... Figure 1 In the left and right directions, one path of hydraulic oil enters the first pressure end 321 of a two-position two-way hydraulic pilot valve 32 located on the left side of the series branch 33 near the oil supply tank 1; the second path of hydraulic oil enters the input end of a two-position two-way hydraulic pilot valve 32 located on the left side of the series branch 33 near the oil supply tank 1; the third path of hydraulic oil enters the input end of a two-position two-way hydraulic pilot valve 32 located on the right side of the series branch 33 near the oil supply tank 1; and the fourth path of hydraulic oil enters the first pressure end 321 of a two-position two-way hydraulic pilot valve 32 located on the right side of the series branch 33 away from the oil supply tank 1. Since the second pressure end of each two-position two-way hydraulic pilot valve 32 on the right side of the series branch 33 is connected to the series branch on both sides of the two-position two-way hydraulic pilot valve 32 via two pressure oil lines 322, the hydraulic oil flow is as follows: When circuit 33 is connected, hydraulic oil flows into one of the pressure lines 322 of a two-position two-way hydraulic pilot valve 32 located near the oil supply tank 1 on the right-side series branch 33. This pushes the two-position two-way hydraulic pilot valve 32 located near the oil supply tank 1 on the right-side series branch 33 from the right position to the left position, connecting the input and output ends of the two-position two-way hydraulic pilot valve 32 located near the oil supply tank 1 on the right-side series branch 33. The hydraulic oil flows out from the output end of the two-position two-way hydraulic pilot valve 32 located near the oil supply tank 1 on the right-side series branch 33 and then flows through one of the second connecting ends of the right-side reversing oil circuit 4 to one of the reversing oil ports 51 of the hydraulic motor 5, driving the hydraulic motor 5 to rotate at a certain speed, thereby driving the temperature control fan 6 to rotate at a certain speed in the first clockwise direction.

[0060] Among them, such as Figure 1 and Figure 2As shown, the thermal management system for bulldozers also includes a safety oil circuit 71 and a safety valve 72. One end of the safety oil circuit 71 is connected to the pipeline connecting the second input ends of the two two-position four-way solenoid valves 31, and the other end is connected to the pipeline connecting the series branch 33 and the oil supply tank 1. The third input end and the third pressure end of the safety valve 72 are both connected to one of its series branches 33, and the output end of the safety valve 72 is connected to the safety oil circuit 71. Specifically, when one of the two two-position four-way solenoid valves 31 is energized and the other is not energized, the four hydraulic oils supplied to the reversing assembly cannot be supplied to the reversing port 51 of the hydraulic motor 5. At this time, the temperature control fan 6 stops rotating, and the four hydraulic oils are in a state of stagnant oil. By setting up the safety oil circuit 71 and the safety valve 72, the four hydraulic oils, after stagnating to a certain pressure, connect the input end and the output end of the safety valve 72 through the pressure end of the safety valve 72, thereby allowing the hydraulic oil to flow from the safety oil circuit 71 to the oil supply tank 1.

[0061] Optionally, such as Figure 1 and Figure 2 As shown, each of the pipelines connecting the two output terminals of the two-position four-way solenoid valve 31 to the first pressure terminals 321 of the two-position two-way hydraulic pilot valves 32 is equipped with a first throttle valve 34. This configuration allows for adjustment of the flow rate of hydraulic oil supplied to the four two-position two-way hydraulic pilot valves 32.

[0062] Preferably, such as Figure 1 and Figure 2 As shown, the thermal management system for bulldozers also includes two buffer oil circuits 91, each corresponding to one of the two directional valve groups 3. One end of each buffer oil circuit 91 is connected to the directional oil circuit 4, and the other end is connected to the pipeline connecting the series branch 33 and the oil supply tank 1. A second electrically controlled check valve 92 is provided on the buffer oil circuit 91, electrically connected to the controller, to guide hydraulic oil from the pipeline connecting the series branch 33 and the oil supply tank 1 to the directional oil circuit 4. This arrangement allows a portion of the hydraulic oil output from a two-position, two-way hydraulic pilot valve 32 on the series branch 33, which is far from the oil supply tank 1, to be buffered by the buffer oil circuit 91 before being returned by the two-position, two-way hydraulic pilot valve 32 and delivered to the oil supply tank 1, thereby improving the stability of hydraulic oil delivery. In other embodiments, the check valve on the buffer oil circuit 91 can also be a mechanical check valve.

[0063] Among them, such as Figure 1 and Figure 2As shown, the flow regulating assembly 2 includes a variable pump body 21, a swashplate 22, a first hydraulic cylinder 23, and a second hydraulic cylinder 24. The pump input end of the variable pump body 21 is connected to the oil supply tank 1. The first pump output end of the variable pump body 21 is connected to both the series branch 33 and the first input end of the two-position four-way solenoid valve 31. The second pump output end of the variable pump body 21 is connected to the first hydraulic cylinder 23. The third pump output end of the variable pump body 21 can be connected to the second hydraulic cylinder 24. The swashplate 22 is connected to both the hydraulic rod of the first hydraulic cylinder 23 and the hydraulic rod of the second hydraulic cylinder 24. By controlling the operation of the variable pump body 21, the variable pump body 21 delivers hydraulic oil from the output end of the first pump to the series branch 33 and the two-position four-way solenoid valve 31, thereby causing the reversing assembly to drive the temperature control fan 6 to rotate forward, reverse, or stop rotating. By setting the output end of the second pump of the variable pump body 21 to be connected to the first hydraulic cylinder 23, and the output end of the third pump of the variable pump body 21 to be connected to the second hydraulic cylinder 24, the hydraulic oil delivered to the first hydraulic cylinder 23 and the hydraulic oil delivered to the second hydraulic cylinder 24 can jointly adjust the rotation of the swashplate 22 to adjust the opening of the variable pump body 21. This allows the flow rate of hydraulic oil delivered to the reversing assembly to be controlled according to the actual heat dissipation requirements, and the speed of the temperature control fan 6 to be adjusted in real time.

[0064] Specifically, such as Figure 1 and Figure 2 As shown, the flow regulating assembly 2 also includes a regulating oil passage 25, a pressure shut-off valve 26, and an inverse proportional solenoid valve 27. One end of the regulating oil passage 25 is connected to the output end of the third pump, and the other end of the regulating oil passage 25 is provided with a first regulating branch 251, a second regulating branch 252, and a third regulating branch 253. The first regulating branch 251 is connected to one of the fourth pressure ends of the pressure shut-off valve 26, the second regulating branch 252 is connected to the fourth input end of the pressure shut-off valve 26, the output end of the pressure shut-off valve 26 is connected to the second hydraulic cylinder 24, and the third connecting end of the pressure shut-off valve 26 is connected to the oil supply tank 1. The third regulating branch 253 is connected to the other fourth pressure end of the pressure shut-off valve 26, and is also connected to the fifth input end and the fifth pressure end of the inverse proportional solenoid valve 27. The output end of the inverse proportional solenoid valve 27 is connected to the oil supply tank 1. Specifically, along... Figure 1In the left and right directions, the hydraulic oil pressure supplied to the fourth pressure end on the left side of the pressure shut-off valve 26 via the first regulating branch 251 and the hydraulic oil pressure supplied to the fourth pressure end on the right side of the pressure shut-off valve 26 via the third regulating branch 253 can control the left or right position operation of the pressure shut-off valve 26. By controlling the current of the inverse proportional solenoid valve 27 and the hydraulic oil supplied to the fifth input end and fifth pressure end of the inverse proportional solenoid valve 27 via the third regulating branch 253, the hydraulic oil pressure at the fourth pressure end on the right side of the pressure shut-off valve 26 can also be controlled, thereby controlling the amount of hydraulic oil flowing into the second hydraulic cylinder 24, so as to realize the rotation of the regulating swashplate 22 and adjust the opening of the variable pump body 21.

[0065] More specifically, such as Figure 1 As shown, the pipeline connecting the output end of the pressure shut-off valve 26 to the second hydraulic cylinder 24 is also connected to the oil supply tank 1 through the circulating oil circuit 281.

[0066] Optionally, such as Figure 1 As shown, a second throttle valve 282 is provided on the circulating oil circuit 281.

[0067] Optionally, such as Figure 1 and Figure 2 As shown, a third throttle valve 29 is provided on the pipeline connecting the output end of the pressure shut-off valve 26 to the second hydraulic cylinder 24.

[0068] Optionally, such as Figure 1 and Figure 2 As shown, a fourth throttle valve 30 is provided on the part of the third regulating branch 253 that is connected to the other fourth pressure end of the pressure shut-off valve 26.

[0069] Preferably, such as Figure 1 and Figure 2 As shown, an oil suction filter 101 is installed on the pipeline connecting the variable pump body 21 and the oil supply tank 1. This configuration can filter the hydraulic oil output from the variable pump body 21, reducing the risk of blockage in the thermal management system of the bulldozer.

[0070] Among them, such as Figure 1 and Figure 2 As shown, the thermal management system for bulldozers also includes a return oil assembly 8, which includes a return oil passage 81. One end of the return oil passage 81 is connected to the series branch 33, and the other end is connected to the oil supply tank 1. This enables the hydraulic oil output from the reversing assembly to flow back to the oil supply tank 1.

[0071] Specifically, such as Figure 1 and Figure 2As shown, the oil return assembly 8 also includes a radiator 82, a two-position two-way solenoid directional valve 83, a first electrically controlled check valve 84, and a first oil return branch 811 and a second oil return branch 812 connected in parallel on the oil return circuit 81. The two-position two-way solenoid directional valve 83 and the radiator 82 are connected in series in the first oil return branch 811, and the first electrically controlled check valve 84 is located in the second oil return branch 812. Specifically, the two-position two-way solenoid directional valve 83 and the first electrically controlled check valve 84 are also electrically connected to the controller. When the two-position two-way solenoid directional valve 83 moves along... Figure 1 When the bulldozer is in the right position, the first electrically controlled check valve 84 is not activated. The returning hydraulic oil flows sequentially through the two-position two-way solenoid valve 83 and the radiator 82, and then into the oil supply tank 1. When the radiator 82 is severely blocked, the controller energizes the two-position two-way solenoid valve 83, which activates the first electrically controlled check valve 84, allowing the hydraulic oil to flow from the first electrically controlled check valve 84 to the oil supply tank 1. When the bulldozer is started in low temperature or extremely cold conditions, the controller also energizes the two-position two-way solenoid valve 83, which activates the first electrically controlled check valve 84, allowing the hydraulic oil to flow from the first electrically controlled check valve 84 to the oil supply tank 1. It can be understood that at this time, the hydraulic oil does not pass through the radiator 82, which enables the thermal management system of the bulldozer to maintain its temperature.

[0072] Specifically, in this embodiment, the hydraulic motor 5 and the temperature-controlled fan 6 are mounted on the bulldozer via a bracket structure and are located in front of the radiator 82. The radiator 82 is mounted behind the intercooler. Preferably, the commutation assembly is located near the hydraulic motor 5 and the temperature-controlled fan 6, which simplifies the piping layout.

[0073] More specifically, such as Figure 1 and Figure 2 As shown, the oil return assembly 8 also includes an oil return filter 85 and a third electrically controlled check valve 86, as well as a third oil return branch and a fourth oil return branch connected in parallel on the oil return circuit 81. The oil return filter 85 is located in the third oil return branch, and the third electrically controlled check valve 86 is located in the fourth oil return branch and electrically connected to the controller. The third oil return branch is located between the first oil return branch 811 and the oil supply tank 1. When the oil return filter 85 is severely clogged, the controller controls the third electrically controlled check valve 86 to operate, causing hydraulic oil to flow from the third electrically controlled check valve 86 to the oil supply tank 1.

[0074] Among them, such as Figure 1 and Figure 2 As shown, the hydraulic motor 5 is connected to the oil supply tank 1 via the first drain oil passage 11 to recover the hydraulic oil leaking from the hydraulic motor 5. Figure 1 and Figure 2 As shown, the variable pump body 21 is connected to the oil supply tank 1 through the second drain oil passage 12 to recover the hydraulic oil leaking from the variable pump body 21.

[0075] The present invention also provides a bulldozer that, by adopting the above-mentioned bulldozer thermal management system, can control the temperature control fan 6 to rotate forward, reverse, or stop rotating according to actual heat dissipation needs, and can also adjust the speed of the temperature control fan 6 in real time, thereby improving the working performance of the bulldozer. It also enables the temperature control fan 6 to stop rotating or rotate at a lower speed when the bulldozer is first started, and / or when heat preservation is required in extremely cold conditions, and / or when rapid heating is required, thus avoiding energy waste.

[0076] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A thermal management system for bulldozers, characterized in that, include: The oil supply tank (1), the flow regulating component (2), and the reversing component are provided. The oil supply tank (1) can supply hydraulic oil to the flow regulating component (2). The flow regulating component (2) is used to regulate the flow rate of the hydraulic oil delivered to the reversing component per unit time. The reversing assembly includes two parallel reversing valve groups (3), each reversing valve group (3) including a two-position four-way solenoid valve (31) and two two-position two-way hydraulic pilot valves (32). The two two-position two-way hydraulic pilot valves (32) are connected in series to form a series branch (33), and the two ends of the series branch (33) are respectively connected to the output end of the flow regulating assembly (2) and the oil supply tank (1); the first input end of the two-position four-way solenoid valve (31) is also connected to the output end of the flow regulating assembly (2), and the two-position four-way solenoid valve (31) The second input terminal of 31) is connected to the second input terminal of the two-position four-way solenoid valve (31) of another reversing valve group (3). The two output terminals of the two-position four-way solenoid valve (31) are respectively connected to the first pressure terminals (321) of the two two-position two-way hydraulic pilot valves (32), so that the hydraulic oil delivered to the reversing assembly is divided into four paths and enters separately. The second pressure terminals of the two two-position two-way hydraulic pilot valves (32) are both connected to the series branch (33). The two-position two-way hydraulic pilot valves (32) can connect or disconnect the series branch (33). Two reversing oil passages (4) are provided one-to-one with two reversing valve groups (3). Each reversing oil passage (4) includes a first connecting end and a second connecting end. The second connecting end is connected to the pipeline between the two two-position two-way hydraulic pilot valves (32) on the series branch (33). Hydraulic motor (5) and temperature control fan (6), the hydraulic motor (5) is provided with two reversing oil ports (51), the two reversing oil ports (51) are correspondingly connected to the first connecting ends of the two reversing oil circuits (4), and the output shaft of the hydraulic motor (5) is connected to the central rotating shaft of the temperature control fan (6). When both of the two two-position four-way solenoid valves (31) are not energized, one hydraulic oil path enters the first pressure end (321) of a two-position two-way hydraulic pilot valve (32) located on the left side of the series branch (33) near the oil supply tank (1), the second hydraulic oil path enters the input end of a two-position two-way hydraulic pilot valve (32) located on the left side of the series branch (33) near the oil supply tank (1), the third hydraulic oil path enters the input end of a two-position two-way hydraulic pilot valve (32) located on the right side of the series branch (33) near the oil supply tank (1), and the fourth hydraulic oil path enters the first pressure end (321) of a two-position two-way hydraulic pilot valve (32) located on the right side of the series branch (33) away from the oil supply tank (1). When both of the two two-position four-way solenoid valves (31) are energized, one hydraulic oil path enters the first pressure end (321) of a two-position two-way hydraulic pilot valve (32) located on the left side of the series branch (33) away from the oil supply tank (1), the second hydraulic oil path enters the input end of a two-position two-way hydraulic pilot valve (32) located on the left side of the series branch (33) near the oil supply tank (1), the third hydraulic oil path enters the input end of a two-position two-way hydraulic pilot valve (32) located on the right side of the series branch (33) near the oil supply tank (1), and the fourth hydraulic oil path enters the first pressure end (321) of a two-position two-way hydraulic pilot valve (32) located on the right side of the series branch (33) near the oil supply tank (1).

2. The thermal management system for bulldozers according to claim 1, characterized in that, The thermal management system for the bulldozer also includes multiple temperature sensors electrically connected to the controller. The multiple temperature sensors include at least an ambient temperature sensor located outside the cab of the bulldozer, a water temperature sensor located in the engine circulating water circuit of the bulldozer, an intake air temperature sensor located in the engine air intake of the bulldozer, and an oil temperature sensor located in the transmission system oil circuit of the bulldozer. The flow regulating component (2) and the two-position four-way solenoid valve (31) are also electrically connected to the controller.

3. The thermal management system for bulldozers according to claim 1, characterized in that, The second pressure end of the two-position two-way hydraulic pilot valve (32) is provided with two pressure oil passages (322). One end of each pressure oil passage (322) is connected to the second pressure end, and the other end of each pressure oil passage (322) is connected to the series branch (33) on both sides of the two-position two-way hydraulic pilot valve (32).

4. The thermal management system for bulldozers according to claim 1, characterized in that, The bulldozer thermal management system also includes a safety oil circuit (71) and a safety valve (72). One end of the safety oil circuit (71) is connected to the pipeline connected to the second input ends of the two two-position four-way solenoid valves (31), and the other end is connected to the pipeline connected to the series branch (33) and the oil supply tank (1). The third input end and the third pressure end of the safety valve (72) are both connected to one of the series branches (33), and the output end of the safety valve (72) is connected to the safety oil circuit (71).

5. The thermal management system for bulldozers according to claim 1, characterized in that, The two output terminals of the two-position four-way solenoid valve (31) are respectively connected to the first pressure terminals (321) of the two two-position two-way hydraulic pilot valves (32) and each of them is provided with a first throttle valve (34).

6. The thermal management system for bulldozers according to any one of claims 1-5, characterized in that, The flow regulating component (2) includes a variable pump body (21), a swashplate (22), a first hydraulic cylinder (23), and a second hydraulic cylinder (24). The pump input end of the variable pump body (21) is connected to the oil supply tank (1). The first pump output end of the variable pump body (21) is connected to both the series branch (33) and the first input end of the two-position four-way solenoid valve (31). The second pump output end of the variable pump body (21) is connected to the first hydraulic cylinder (23). The third pump output end of the variable pump body (21) is connected to the second hydraulic cylinder (24). The swashplate (22) is connected to both the hydraulic rod of the first hydraulic cylinder (23) and the hydraulic rod of the second hydraulic cylinder (24).

7. The thermal management system for bulldozers according to claim 6, characterized in that, The flow regulating component (2) further includes a regulating oil circuit (25), a pressure shut-off valve (26), and an inverse proportional solenoid valve (27). One end of the regulating oil circuit (25) is connected to the output end of the third pump. The other end of the regulating oil circuit (25) is provided with a first regulating branch (251), a second regulating branch (252), and a third regulating branch (253). The first regulating branch (251) is connected to a fourth pressure end of the pressure shut-off valve (26). The second regulating branch (252) is connected to the fourth input end of the pressure shut-off valve (26). The output end of the pressure shut-off valve (26) is connected to the second hydraulic cylinder (24). The third connecting end of the pressure shut-off valve (26) is connected to the oil supply tank (1). The third regulating branch (253) is connected to the other fourth pressure end of the pressure shut-off valve (26), and is also connected to the fifth input end and the fifth pressure end of the inverse proportional solenoid valve (27). The output end of the inverse proportional solenoid valve (27) is connected to the oil supply tank (1).

8. The thermal management system for bulldozers according to any one of claims 1-5, characterized in that, The heat management system for bulldozers also includes an oil return assembly (8), which includes an oil return path (81). One end of the oil return path (81) is connected to the series branch (33), and the other end of the oil return path (81) is connected to the oil supply tank (1).

9. The thermal management system for bulldozers according to claim 8, characterized in that, The oil return assembly (8) also includes a radiator (82), a two-position two-way solenoid directional valve (83), a first electrically controlled check valve (84), and a first oil return branch (811) and a second oil return branch (812) connected in parallel on the oil return circuit (81). The two-position two-way solenoid directional valve (83) and the radiator (82) are connected in series in the first oil return branch (811), and the first electrically controlled check valve (84) is located in the second oil return branch (812).

10. A bulldozer, characterized in that, Includes the thermal management system for bulldozers as described in any one of claims 1-9.

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