Axle staged cooling system, axle staged cooling assembly and engineering vehicle

Abstract

The invention discloses an axle staged cooling system, an axle staged cooling assembly and an engineering vehicle. The axle staged cooling system comprises an engine first-stage cooling system, an engine second-stage cooling system, an axle first-stage cooling system and an axle second-stage cooling system. Each stage of cooling system controls cooling water and oil path trend through a thermolator in each loop, controls axle cooling oil and engine cooling water to exchange heat, and meets different cooling requirements of an axle. The temperature sensor in each loop outputs water and oil temperature signals to a motor of the cooling fan, so that the rotating speed of the fan is increased to different degrees along with the temperature rise of each cooling system, and different cooling powers are matched. According to the grading system, the engine and the axles can work at the proper temperature at the same time, the two heat exchangers cool cooling oil of the front axle, cooling oil of the middle axle and cooling oil of the rear axle respectively, the cooling capacity of the front axle is improved, the braking effectiveness of the front axle is guaranteed, and rollover caused by serious backward movement of the gravity center of a vehicle during emergency braking is prevented.

Description

Technical Field

[0001] This invention relates to a graded cooling system for vehicle axles, belonging to the field of engineering machinery, and can be used in mining dump trucks, especially articulated dump trucks. Background Technology

[0002] Mining dump trucks, especially articulated dump trucks, are mostly used in areas with high temperatures and muddy roads year-round. They often employ a three-axle, six-wheel drive system with wet brakes to handle tire slippage and long, heavy-load downhill conditions. During prolonged braking, the wheel-side brakes easily overheat, requiring cooling oil to dissipate the heat. Two common technical solutions exist: one is axle self-cooling, where an oil circuit is formed inside the axle, circulating the cooling oil between the left and right wheel brakes. This solution is simple to implement, requiring only consideration of axle installation space for the OEM. However, the axle's self-cooling capacity is limited, necessitating a transmission queuing function to meet the demands of heavy-load, long downhill conditions. The other solution involves leading the axle cooling oil out of the axle and configuring an independent radiator, fan, drive pump, and control valve to form an independent cooling circuit. The advantage is system independence; with sufficient cooling power, a vehicle queuing function can be achieved. However, this involves more components, making implementation difficult on compact vehicles like articulated trucks. Furthermore, since cooling is independent of the overall vehicle thermal management, cooling power is wasted, hindering effective overall vehicle thermal management. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a graded cooling system for axles, which exchanges heat between the vehicle's cooling water circuit and the axle's cooling oil circuit, and achieves graded cooling of the axle by controlling different circuits.

[0004] To achieve the above objectives, the present invention is implemented according to the following technical solution:

[0005] In a first aspect, the present invention provides a graded cooling system for an axle of an engineering vehicle, including a first and second stage cooling system for the engine and a first and second stage cooling system for the axle;

[0006] The engine's first and second stage cooling systems include the engine, water pump I, thermostat a, radiator, and cooling fan;

[0007] When the water temperature flowing through thermostat a is lower than the thermostat threshold T0, thermostat a connects the engine to the water pump I circuit, and the cooling water flows directly back to the engine through water pump I, completing the first stage of cooling system circulation;

[0008] When the water temperature flowing through thermostat a is higher than the thermostat threshold T0, thermostat a connects the engine and radiator water circuit and starts the cooling fan to cool the cooling water in the radiator. After cooling, the cooling water flows back to the engine through water pump I, completing the second stage of the cooling system cycle.

[0009] The axle's first and second stage cooling systems include the axle, oil pump, oil tank, thermostat b, heat exchanger a, and water pump II;

[0010] When the oil temperature flowing through thermostat b is lower than the thermostat threshold T1, thermostat b connects the oil pump to the axle's oil circuit. The oil pump delivers the cooling oil from the oil tank to the axle, cools the axle, and then flows back to the oil tank, completing the first stage of the cooling system cycle.

[0011] When the oil temperature flowing through thermostat b is higher than the thermostat threshold T1, thermostat b connects the oil pump to the oil circuit of heat exchanger a. The oil pump delivers the cooling oil in the oil tank to one side of the heat exchanger a channel, and water pump II delivers the cooling water flowing through the radiator to the other side of the heat exchanger a channel. After heat exchange, the cooling oil enters the axle, cools the axle, and then flows back to the oil tank, completing the second stage of the cooling system cycle.

[0012] In some embodiments, the axle includes a front axle and a rear axle, the thermostat b includes thermostat II and thermostat III, the heat exchanger a includes heat exchanger I and heat exchanger II, and the oil pump includes oil pump I and oil pump II; wherein, oil pump I, thermostat II, and heat exchanger I are connected to the front axle, and oil pump II, thermostat III, and heat exchanger II are connected to the rear axle, thereby forming two independent cooling systems.

[0013] In some embodiments, temperature sensors are installed on the oil inlets of both the front and rear axles to transmit the monitored oil temperature signals to the cooling fans. When the engine's second-stage cooling system and the axle's second-stage cooling system operate simultaneously, the cooling fan speed is adjusted according to the engine's inlet water temperature and the inlet oil temperatures of the front and rear axles. The specific adjustment process is as follows:

[0014] Assuming the fan speed is n1 when the water temperature is t0, the front axle oil temperature is t1, and the rear axle oil temperature is t2, and the engine water temperature rises by Δt0, the front axle oil temperature rises by Δt1, and the rear axle temperature rises by Δt2;

[0015] The fan speed n2 = n1 * (1 + λ0 * Δt0 / t0 + λ1 * Δt1 / t1 + λ2 * Δt2 / t2), where λ1 ≥ λ2 > λ0, and the speed is adjusted according to the cooling oil demand of the axle.

[0016] In some embodiments, a temperature sensor is installed at the engine's water inlet to transmit the monitored water temperature signal to the cooling fan. When the engine's second-stage cooling system operates independently, the cooling fan increases its speed according to the increase in the engine's water inlet temperature, thereby increasing the fan speed and enhancing the radiator's heat dissipation capacity.

[0017] In some embodiments, thermostat a has one inlet and two outlets, and is arranged in the engine cooling water circuit to control the direction of cooling water according to the oil temperature threshold T0; thermostat b has one inlet and two outlets, and is arranged in the axle cooling oil circuit to control the direction of cooling oil according to the oil temperature threshold T1.

[0018] In some embodiments, the radiator and cooling fan are arranged inside the engine hood, with air entering from the front of the hood, the cooling fan drawing the air onto the radiator, and the air exiting the hood from the other side of the radiator.

[0019] In some embodiments, the water pump I is an engine-mounted water pump installed on the engine body, with the drive wheel connected to the engine crankshaft via a gear system or belt. During engine operation, the water pump I is always running to circulate the engine cooling water circuit; and / or, the water pump II, oil pump I, and oil pump II are connected to the engine PTO, using a drive shaft remote connection or a direct connection to the PTO.

[0020] Secondly, the present invention provides a graded cooling assembly for an axle, comprising the aforementioned graded cooling system for an axle, a transmission, a water pump clutch, and a heat exchanger b; the transmission is connected to the engine, the water pump clutch is connected to water pump II, a temperature sensor and an oil pump are installed on the transmission, the temperature sensor is electrically connected to the water pump clutch, the oil pump is connected to one side of the heat exchanger b, and the other side of the heat exchanger b is connected to heat exchanger a; when the temperature sensor detects that the oil temperature is higher than the threshold T2, the water pump clutch controls the speed of water pump II, and the oil pump delivers transmission cooling oil to the heat exchanger b. The cooling water that has exchanged heat with the axle cooling oil flows back into the heat exchanger b to exchange heat with the transmission oil, thus completing the cooling of the transmission oil.

[0021] Thirdly, the present invention provides a graded cooling assembly for an axle, comprising the aforementioned graded cooling system for an axle, a transmission, a water pump clutch, and a heat exchanger b; the transmission is connected to the engine, the water pump clutch is connected to water pump II, a temperature sensor and an oil pump are installed on the transmission, the temperature sensor is electrically connected to the water pump clutch, the oil pump is connected to one side of the heat exchanger b, and the other side of the heat exchanger b is connected to water pump II; when the temperature sensor detects that the oil temperature is higher than the threshold T2, the water pump clutch controls the speed of water pump II, the oil pump delivers transmission cooling oil to the heat exchanger b, and the cooling water in water pump II flows into the heat exchanger b to exchange heat with the transmission oil, thereby completing the cooling of the transmission oil.

[0022] Fourthly, the present invention provides an engineering vehicle including the aforementioned axle graded cooling system;

[0023] Alternatively, including the aforementioned axle tiered cooling assembly;

[0024] Alternatively, it could include the aforementioned axle tiered cooling assembly.

[0025] Based on the application of the above technical solutions, the beneficial effects of this invention compared with the prior art are as follows:

[0026] This invention achieves graded cooling of the axle by rationally arranging heating, cooling, driving, and monitoring elements to form a multi-stage cooling circuit for the engine and axle. When the axle cooling oil temperature is low, the fan motor speed is only affected by the engine coolant temperature. At this time, the fan consumes little energy and has low noise, and the axle cooling oil flows directly back to the oil tank to complete heat dissipation. When the axle cooling oil temperature is high, the water pump operates, and the fan motor adjusts its speed according to the engine coolant temperature and axle oil temperature signals, ensuring that the axle cooling oil, after heat exchange with the coolant, is at a suitable temperature for axle operation. Two heat exchangers are arranged, one for the front axle and one shared by the middle and rear axles. Compared with the scheme where three axles share one heat exchanger, the advantages are: firstly, changing one large heat exchanger to two reduces the size of the heat exchangers and facilitates their arrangement; secondly, it improves the cooling capacity of the front axle, ensures the effectiveness of front axle braking, and prevents the vehicle's center of gravity from shifting backward and causing rollover during emergency braking. The radiator and fan are preferably located on the front side of the vehicle. The fan can draw air out of the engine hood. Compared with the common solution of directly connecting the fan to the front of the engine, this reduces the intake resistance of the radiator and effectively lowers the air temperature inside the engine hood, making it suitable for higher temperature operating conditions. Attached Figure Description

[0027] The accompanying drawings, as part of this invention, are provided to further illustrate the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation thereof. Clearly, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0028] In the attached diagram:

[0029] Figure 1 This is a schematic diagram of the connection of a graded cooling system for a vehicle axle according to the present invention;

[0030] Figure 2 This is a schematic diagram of the connection of the first-stage cooling system of the engine according to the present invention;

[0031] Figure 3 This is a schematic diagram of the connection of the second-stage cooling system of the engine according to the present invention;

[0032] Figure 4 This is a schematic diagram of the connection of the first-stage cooling system of the axle according to the present invention;

[0033] Figure 5This is a schematic diagram of the circulation connection of the second-stage cooling system of the axle according to the present invention;

[0034] Figure 6 This is a schematic diagram of the first application of the graded cooling system for vehicle axles described in this invention;

[0035] Figure 7 This is a schematic diagram illustrating a second application of the graded cooling system for vehicle axles described in this invention.

[0036] Explanation of reference numerals in the attached diagram: 1. Engine; 2. Radiator; 3. Fan; 4. Fan motor; 5. Thermostat I; 6. Water pump I; 7. Heat exchanger I; 8. Heat exchanger II; 9. Front axle; 10. Middle axle; 11. Rear axle; 12. Water pump II; 13. Oil pump I; 14. Oil pump II; 15. Thermostat II; 16. Thermostat III; 17. Temperature sensor I; 18. Temperature sensor II; 19. Temperature sensor III; 20. Fuel tank; 21. Gearbox; 22. Heat exchanger III; 23. Water pump clutch.

[0037] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0039] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0040] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] like Figure 1As shown, the present invention provides a graded cooling system for axles of engineering vehicles, including a heat-generating element, a cooling element, a drive element, and a monitoring element; the heat-generating element includes an engine 1, a front axle 9, a middle axle 10, and a rear axle 11; the cooling element includes a radiator 2, a cooling fan (composed of a fan 3 and a fan motor 4), a heat exchanger I 7, and a heat exchanger II 8; the drive element includes a water pump I 6, a water pump II 12, an oil pump I 13, and an oil pump II 14; the monitoring element includes a temperature sensor I 17, a temperature sensor II 18, and a temperature sensor III 19.

[0042] Figure 2 The diagram shows the first-stage cooling system of the engine according to the present invention, which consists of an engine 1, a water pump I6, a thermostat I5, and connecting water pipes. The water pump I6, engine 1, and thermostat I5 are connected together in sequence by water pipes. The water pump I6 inputs water into engine 1 to cool the engine interior. The thermostat I5 has one inlet and two outlets. When the water temperature of engine 1 is lower than the thermostat threshold T0 at the initial start-up stage, the thermostat I5 connects the water circuit of engine 1 and water pump I6, and the cooling water flows directly back to engine 1 through water pump I6, completing the first-stage cooling system circulation.

[0043] Figure 3 The second-stage cooling system of the engine described in this invention consists of an engine 1, a water pump I6, a thermostat I5, a radiator 2, a fan 3, a fan motor 4, and connecting water pipes. When the water temperature flowing through the thermostat I5 is higher than the thermostat threshold T0, the thermostat I5 connects the water circuit between the engine 1 and the radiator 2 and transmits a signal to the fan motor 4. The fan motor 4 starts, driving the fan 3 to cool the cooling water in the radiator 2. After cooling, the cooling water flows back to the engine 1 via the water pump I6, completing the second-stage cooling system cycle. The temperature sensor III19 monitors the temperature of the cooling water entering the engine 1 inlet and transmits the water temperature signal to the fan motor 4. The motor speed increases as the cooling water temperature rises, improving the heat dissipation capacity of the radiator 2 and maintaining the engine water temperature within the engine's comfortable range.

[0044] Figure 4 The first-stage cooling system for the axle described in this invention comprises a front axle 9, a middle axle 10, a rear axle 11, oil pump I 13, oil pump II 14, an oil tank 20, a thermostat II 15, a thermostat III 16, and related oil circuits. When the oil temperature is lower than the threshold T1 of thermostat II 15 and thermostat III 16, the thermostat connects the oil pumps to the oil circuits of the axle. Oil pumps I 13 and II 14 respectively deliver oil from the oil tank 20 to the front axle 9, middle axle 10, and rear axle 11 to cool the wheel-side brakes, gear system, etc., within the axle. The oil then flows back to the oil tank 20, completing the cooling cycle. At this time, the axle cooling is mainly achieved by the oil naturally cooling within the oil tank.

[0045] Figure 5The second-stage cooling system for the axle described in this invention comprises a front axle 9, a middle axle 10, a rear axle 11, an oil pump I 13, an oil pump II 14, an oil tank 20, a thermostat II 15, a thermostat III 16, a heat exchanger I 7, a heat exchanger II 8, a water pump II 12, a radiator 2, a fan 3, a fan motor 4, and related oil circuits. The heat exchanger has a dual-channel structure, with oil and water flowing in separate channels to complete heat exchange. When the oil temperature exceeds the threshold T1 of thermostats I and II, the thermostat connects the oil pump to the oil circuit of the heat exchanger and transmits a signal to water pump II12. Water pump II12 starts, and oil pumps I13 and II14 respectively deliver oil from the oil tank 20 to one channel of heat exchangers I7 and II8. Water pump II12 delivers cooling water flowing through radiator 2 to the other channel of heat exchangers I7 and II8. After heat exchange, the cooled oil enters the front, middle, and rear axles for cooling and then returns to the oil tank 20. Temperature sensors I17 and II18 monitor the temperature of the cooling oil entering the front axle 9 and middle axle 10 respectively and transmit signals to the fan motor 4. The motor speed increases as the cooling oil temperature rises, improving the heat dissipation capacity of radiator 2 and maintaining the engine coolant temperature within the engine's comfortable range.

[0046] A further proposed solution involves installing a temperature sensor I17 at the oil inlet of the front axle 9 and a temperature sensor II18 at the oil inlet of the middle axle 10. These sensors transmit the monitored oil temperature signals to the fan motor 4. When the second-stage cooling systems of the engine 1 and the axles operate simultaneously, the fan motor 4 adjusts its fan speed based on the inlet water temperature of the engine 1 and the inlet oil temperatures of the front axle 9 and the middle axle 10. The specific adjustment process is as follows:

[0047] Assuming the fan speed is n1 when the water temperature is t0, the front axle oil temperature is t1, and the middle axle oil temperature is t2, and the engine water temperature rises by Δt0, the front axle oil temperature rises by Δt1, and the middle axle temperature rises by Δt2;

[0048] The fan speed n2 = n1 * (1 + λ0 * Δt0 / t0 + λ1 * Δt1 / t1 + λ2 * Δt2 / t2), where λ1 ≥ λ2 > λ0, and the speed is adjusted according to the cooling oil demand of the axle.

[0049] As described above, this invention comprises first and second stage cooling systems for the engine and first and second stage cooling systems for the axles. Each stage of the cooling system controls the flow of coolant and oil through thermostats in its respective circuit, controlling the heat exchange between the axle cooling oil and engine coolant to meet the different cooling requirements of the axles. Temperature sensors in each circuit output water and oil temperature signals to the cooling fan motors, causing the fan speed to increase to varying degrees as the temperature of each cooling system rises, matching different cooling power requirements. The graded system described in this invention allows the engine and axles to operate at suitable temperatures simultaneously. Two heat exchangers cool the front, middle, and rear axle cooling oils respectively, improving the front axle cooling capacity, ensuring front axle braking effectiveness, and preventing severe rearward shift of the vehicle's center of gravity during emergency braking, thus preventing rollover.

[0050] The connection relationship and function of the thermostat I described above will be further explained below.

[0051] The thermostat I5 has one inlet and two outlets and is located in the engine cooling water circuit. It controls the flow of cooling water according to the thermostat threshold T0. When the water temperature is lower than the thermostat threshold T0, the thermostat I5 connects the cooling water circuit of engine 1 and water pump I6. At this time, radiator 2 and fan 3 do not work. When the water temperature is higher than the thermostat threshold T0, the thermostat I5 connects the cooling water circuit of engine 1 and radiator 2 and sends a signal to fan motor 4 to start the motor. The cooling water flows through radiator 2 for cooling and then flows back to the engine through water pump I6. At this time, radiator 2 works, and fan motor 4 and fan 3 work.

[0052] The connection relationship and function of the thermostat II and thermostat III mentioned above will be further explained below.

[0053] Both thermostats II15 and III16 have one inlet and two outlets, and are located in the axle cooling oil circuit. They control the flow of cooling oil according to the oil temperature threshold T1. When the oil temperature is lower than the thermostat threshold T1, the thermostat connects the oil pump to the axle's cooling oil circuit. A portion of the cooling oil is drawn from the oil tank 20 by oil pump I13 and flows into the front axle 9, while the other portion is drawn from the middle axle 10 and the rear axle 11 by oil pump II14. Finally, the oil flowing out of the axle merges and returns to the oil tank 20. At this time, the water pump II 12 does not work, and the fan motor 4 is not affected by the axle oil temperature. When the oil temperature is higher than the thermostat threshold T1, the thermostat connects the oil pump to the heat exchanger and sends a signal to the water pump II 12. The water pump II 12 starts and delivers the water cooled by the radiator 2 to the heat exchanger to exchange heat with the cooling oil delivered from the oil pump. The cooled cooling oil enters the axle to cool the axle components.

[0054] In a further embodiment, water pump I is typically an engine-mounted water pump installed on the engine body. The drive wheel is connected to the engine crankshaft via a gear system or belt. Water pump I is always running during engine operation, circulating the engine cooling water circuit.

[0055] In a further proposed solution, water pump II, oil pump I, and oil pump II are generally connected to the engine PTO. They can be installed using a drive shaft for remote connection or a direct connection to the PTO. The preferred method for controlling the pumps is a proportional valve. Oil pump I and oil pump II can be connected in series and share a single PTO. Water pump II can receive signals from thermostat II and thermostat III to start.

[0056] In a further proposed design, the radiator and fan are preferably located on the front side of the vehicle, inside the engine hood. Air enters from the front of the engine hood, the side fan draws the air onto the radiator, and exhausts it from the other side of the radiator out of the engine hood. The fan motor is controlled by an independent hydraulic circuit and can receive signals from the engine coolant temperature and axle oil temperature to adjust its speed. The adjustment method can be controlled by a clutch or a proportional valve.

[0057] The following is an application example of the above-mentioned axle graded cooling system.

[0058] like Figure 6 As shown, a vehicle axle staged cooling assembly includes the aforementioned vehicle axle staged cooling system, a gearbox 21, a water pump clutch 23, and a heat exchanger III 22. The gearbox 21 is connected to the engine 1, the water pump clutch 23 is connected to the water pump II 12, a temperature sensor and an oil pump are installed on the gearbox 21, the temperature sensor is electrically connected to the water pump clutch 23, the oil pump is connected to one side of the heat exchanger III 22, and the other side of the heat exchanger III 22 is connected to the heat exchanger I 7 and the heat exchanger II 8.

[0059] When the temperature sensor inside the transmission 21 detects that the transmission fluid temperature has risen to the threshold T2, a signal is sent to the water pump clutch 23 to control the speed of the water pump II 12. The transmission 21's built-in oil pump then delivers transmission coolant to the heat exchanger III 22. The coolant, which has exchanged heat with the axle coolant, flows back into the heat exchanger III 22 to exchange heat with the transmission fluid, thus cooling the transmission fluid. This solution has a wide range of applications because the transmission's high-temperature tolerance is generally higher than that of the axle. Furthermore, when the axle can be externally cooled, the transmission's easing function can be replaced by the axle's braking. In this case, the transmission requires less cooling power, so the coolant that has exchanged heat with the axle coolant can be used again to exchange heat with the transmission coolant, achieving full utilization of the coolant circulation. When the axle requires less cooling, the water pump clutch can receive the transmission fluid temperature signal to start the water pump and control its speed, allowing for separate circulation of the transmission coolant.

[0060] The following is another application example of the above-mentioned axle graded cooling system.

[0061] like Figure 7 As shown, a graded cooling assembly for an axle includes the aforementioned graded cooling system, a transmission 21, a water pump clutch 23, and a heat exchanger III 22. The transmission 21 is connected to the engine 1, and the water pump clutch 23 is connected to a water pump II 12. A temperature sensor and an oil pump are installed on the transmission 21. The temperature sensor is electrically connected to the water pump clutch 23, and the oil pump is connected to one side of the heat exchanger III 22, while the other side of the heat exchanger III 22 is connected to the water pump II 17. When the temperature sensor in the transmission 21 detects that the oil temperature is higher than a threshold T2, it controls the speed of the water pump II 17 via the water pump clutch 23. The oil pump delivers transmission cooling oil to the heat exchanger III 22, and the cooling water in the water pump II 17 flows into the heat exchanger III 22 to exchange heat with the transmission oil, thus cooling the transmission oil.

[0062] Unlike the implementation examples mentioned above, water pump II17 directly delivers the cooled water, after it has been cooled by the radiator, to heat exchanger III22 to exchange heat with the transmission cooling oil. This solution is mainly used in scenarios where the transmission cooling power requirement is high, such as when the transmission is connected to a high-torque PTO, when the transmission's slowing function needs to be synchronized with the axle braking during heavy-load steep descent, or when the transmission torque converter has a large capacity.

[0063] In summary, this invention provides a graded cooling system for vehicle axles, achieving the following functions and effects:

[0064] This invention achieves graded cooling of the axle by rationally arranging heating, cooling, driving, and monitoring elements to form a multi-stage cooling circuit for the engine and axle. When the axle cooling oil temperature is low, the fan motor speed is only affected by the engine coolant temperature. At this time, the fan consumes little energy and has low noise, and the axle cooling oil flows directly back to the oil tank to complete heat dissipation. When the axle cooling oil temperature is high, the water pump operates, and the fan motor adjusts the fan speed according to the engine coolant temperature and the front and middle axle oil temperature signals, so that the axle cooling oil after heat exchange with the coolant is at an axle-friendly level, allowing the axle to operate at a suitable temperature. Two heat exchangers are arranged, one for the front axle and one shared by the middle and rear axles. Compared with the scheme of three axles sharing one heat exchanger, the advantages are: firstly, changing one large heat exchanger to two reduces the size of the heat exchangers and facilitates their arrangement; secondly, it improves the cooling capacity of the front axle, ensures the effectiveness of front axle braking, and prevents the vehicle's center of gravity from shifting backward and causing rollover during emergency braking. The radiator and fan are preferably located on the front side of the vehicle. The fan can draw air out of the engine hood. Compared with the common solution of directly connecting the fan to the front of the engine, this reduces the air intake resistance of the radiator, effectively lowers the air temperature inside the engine hood, and can adapt to higher temperature operating conditions.

[0065] The engineering vehicle provided by the present invention is described below. The engineering vehicle described below can be referred to in correspondence with the axle graded cooling system described above.

[0066] The present invention provides an engineering vehicle that may include the axle graded cooling system as described in any of the above embodiments.

[0067] The beneficial effects achieved by the engineering vehicle provided by this invention are consistent with the beneficial effects achieved by the axle graded cooling system provided by this invention, so they will not be repeated here.

[0068] It should be noted that the aforementioned engineering vehicles can be articulated dump trucks.

[0069] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0070] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features found in other embodiments but not others, combinations of features from different embodiments are also within the scope of protection of this invention and form different embodiments. For example, in the embodiments described above, those skilled in the art can use them in combination based on known technical solutions and the technical problems to be solved by this application.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A graded cooling system for axles of engineering vehicles, characterized in that, This includes the engine's primary and secondary cooling systems and the axle's primary and secondary cooling systems; The engine's first and second stage cooling systems include the engine, water pump I, thermostat a, radiator, and cooling fan; When the water temperature flowing through thermostat a is lower than the thermostat threshold T0, thermostat a connects the engine to the water pump I circuit, and the cooling water flows directly back to the engine through water pump I, completing the first stage of cooling system circulation; When the water temperature flowing through thermostat a is higher than the thermostat threshold T0, thermostat a connects the engine and radiator water circuit and starts the cooling fan to cool the cooling water in the radiator. After cooling, the cooling water flows back to the engine through water pump I, completing the second stage of the cooling system cycle. The axle's first and second stage cooling systems include the axle, oil pump, oil tank, thermostat b, heat exchanger a, and water pump II; When the oil temperature flowing through thermostat b is lower than the thermostat threshold T1, thermostat b connects the oil pump to the axle's oil circuit. The oil pump delivers the cooling oil from the oil tank to the axle, cools the axle, and then flows back to the oil tank, completing the first stage of the cooling system cycle. When the oil temperature flowing through thermostat b is higher than the thermostat threshold T1, thermostat b connects the oil pump to the oil circuit of heat exchanger a. The oil pump delivers the cooling oil in the oil tank to one side of the heat exchanger a channel, and water pump II delivers the cooling water flowing through the radiator to the other side of the heat exchanger a channel. After heat exchange, the cooling oil enters the axle, cools the axle, and then flows back to the oil tank, completing the second stage of the cooling system cycle.

2. The axle graded cooling system according to claim 1, characterized in that: The axle includes a front axle and a rear axle, the thermostat b includes thermostat II and thermostat III, the heat exchanger a includes heat exchanger I and heat exchanger II, and the oil pump includes oil pump I and oil pump II. The oil pump I, thermostat II, and heat exchanger I are connected to the front axle, while the oil pump II, thermostat III, and heat exchanger II are connected to the rear axle, thus forming two independent cooling systems.

3. The axle graded cooling system according to claim 2, characterized in that: Temperature sensors are installed on the oil inlets of both the front and rear axles to transmit the monitored oil temperature signals to the cooling fans. When the engine's second-stage cooling system and the axle's second-stage cooling system operate simultaneously, the cooling fan speed is adjusted according to the engine's inlet water temperature and the inlet oil temperatures of the front and rear axles. The specific adjustment process is as follows: Assuming the fan speed is n1 when the water temperature is t0, the front axle oil temperature is t1, and the rear axle oil temperature is t2, and the engine water temperature rises by Δt0, the front axle oil temperature rises by Δt1, and the rear axle temperature rises by Δt2; The fan speed n2 = n1 * (1 + λ0 * Δt0 / t0 + λ1 * Δt1 / t1 + λ2 * Δt2 / t2), where λ1 ≥ λ2 > λ0, and the speed is adjusted according to the cooling oil demand of the axle.

4. The axle graded cooling system according to claim 1, characterized in that: The engine's water inlet is equipped with a temperature sensor to transmit the monitored water temperature signal to the cooling fan. When the engine's second-stage cooling system is working independently, the cooling fan speed increases according to the rise in the engine's water inlet temperature, thereby increasing the fan speed and enhancing the radiator's heat dissipation capacity.

5. The axle graded cooling system according to claim 1, characterized in that: The thermostat a has one inlet and two outlets, and is arranged in the engine cooling water circuit to control the direction of cooling water according to the oil temperature threshold T0. The thermostat b has one inlet and two outlets, and is arranged in the axle cooling oil circuit to control the flow of cooling oil according to the oil temperature threshold T1.

6. The axle graded cooling system according to claim 1, characterized in that: The radiator and cooling fan are arranged inside the engine hood. Air enters from the front of the engine hood, the cooling fan draws the air onto the radiator, and the air is discharged from the other side of the radiator from the hood.

7. The axle graded cooling system according to claim 1, characterized in that: The water pump I is an engine-mounted water pump, installed on the engine body. Its drive wheel is connected to the engine crankshaft via a gear system or belt. Water pump I is constantly running during engine operation, circulating the engine's cooling water circuit; and / or The water pump II, oil pump I, and oil pump II are connected to the engine PTO, using either a remote drive shaft connection or a direct connection to the PTO.

8. A graded cooling assembly for an axle, characterized in that: Includes the axle graded cooling system, gearbox, water pump clutch, and heat exchanger b as described in any one of claims 1 to 7; The gearbox is connected to the engine, the water pump clutch is connected to water pump II, a temperature sensor and an oil pump are installed on the gearbox, the temperature sensor is electrically connected to the water pump clutch, the oil pump is connected to one side of the heat exchanger b, and the other side of the heat exchanger b is connected to the heat exchanger a. When the temperature sensor detects that the oil temperature is higher than the threshold T2, the water pump clutch controls the speed of water pump II. The oil pump delivers the transmission coolant to the heat exchanger b. The coolant that has exchanged heat with the axle coolant flows back into the heat exchanger b to exchange heat with the transmission oil, thus completing the cooling of the transmission oil.

9. A graded cooling assembly for an axle, characterized in that: Includes the axle graded cooling system, gearbox, water pump clutch, and heat exchanger b as described in any one of claims 1 to 7; The gearbox is connected to the engine, the water pump clutch is connected to water pump II, a temperature sensor and an oil pump are installed on the gearbox, the temperature sensor is electrically connected to the water pump clutch, the oil pump is connected to one side of the heat exchanger b, and the other side of the heat exchanger b is connected to water pump II. When the temperature sensor detects that the oil temperature is higher than the threshold T2, the water pump clutch controls the speed of water pump II. The oil pump delivers the transmission coolant to the heat exchanger b. The coolant in water pump II flows into the heat exchanger b and exchanges heat with the transmission oil to complete the cooling of the transmission oil.

10. An engineering vehicle, characterized in that: Includes the axle graded cooling system as described in any one of claims 1 to 7; Alternatively, it may include the axle graded cooling assembly as described in claim 8; Alternatively, it may include the axle graded cooling assembly as described in claim 9.

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