A loader independent cooling system

Abstract

This utility model relates to the field of loader cooling technology, and provides an independent cooling system for loaders, including a variable displacement pump and an oil tank. The input end of the variable displacement pump is connected to the oil tank, and the output end is connected to a pilot control oil circuit and a cooling oil supply oil circuit. The pilot control oil circuit includes a first control oil circuit and a second control oil circuit. The cooling oil supply oil circuit includes a proportional flow distribution valve, a pressure compensation valve, and an overload replenishment valve. The proportional flow distribution valve is connected to the output end of the variable displacement pump and the pressure compensation valve, and the overload replenishment valve is connected to the proportional flow distribution valve and the fan motor. The first control oil circuit is connected to the pressure compensation valve. The second control oil circuit includes a pressure oil source valve and an electro-proportional pressure reducing valve. The pressure oil source valve is connected to the output end of the variable displacement pump, and the electro-proportional pressure reducing valve is connected to the pressure oil source valve and the proportional flow distribution valve. This utility model can supply oil on demand without flow loss, and achieves smooth fan reversal, reduces hydraulic shock, extends service life, avoids excessive internal system pressure, and protects hydraulic components.

Description

Technical Field

[0001] This utility model relates to the field of loader heat dissipation technology, specifically to an independent heat dissipation system for loaders. Background Technology

[0002] Currently, loader cooling systems are mainly engine direct-drive cooling systems. In these systems, the cooling fan is connected to the engine crankshaft via a belt. The engine drives the fan to rotate, blowing air onto the radiator for cooling. The fan speed in this system is directly proportional to the engine speed and cannot adjust according to temperature. In cold regions, excessively high fan speeds affect warm-up time, increase fuel consumption and noise, and the fan cannot reverse, requiring regular manual cleaning of the radiator. To address these issues, existing technology has designed a hydraulic motor-driven independent cooling system. In this system, the fan is decoupled from the engine and driven by a hydraulic motor. The fan speed can increase or decrease according to temperature and can rotate in reverse, eliminating the need for manual radiator cleaning.

[0003] In the independent cooling system of the hydraulic motor, when the fan is at low speed, excess flow overflows through the relief valve, resulting in energy loss; and when the fan changes from clockwise to counterclockwise or vice versa, there is hydraulic shock, which affects the lifespan of the motor and fan.

[0004] Therefore, in order to address the above problems, an independent cooling system for loaders is proposed. Utility Model Content

[0005] This invention addresses the shortcomings of existing technologies by developing an independent cooling system for loaders. This system can supply oil on demand, with no flow loss, good economy, smooth fan reversal, reduced hydraulic shock, extended service life, and prevents excessive internal system pressure, thus protecting hydraulic components.

[0006] To achieve the above objectives, this utility model employs the following technical solution:

[0007] An independent cooling system for a loader includes a variable displacement pump and an oil tank. The variable displacement pump is driven by a motor. The input end of the variable displacement pump is connected to the oil tank, and the output end of the variable displacement pump is connected to a pilot control oil circuit and a cooling oil supply oil circuit. The pilot control oil circuit includes a first control oil circuit and a second control oil circuit. The cooling oil supply oil circuit includes a proportional flow distribution valve, a pressure compensation valve, and an overload replenishment valve. The proportional flow distribution valve is connected to the output end of the variable displacement pump and the pressure compensation valve. The overload replenishment valve is connected to the proportional flow distribution valve and a fan motor. The first control oil circuit is connected to the pressure compensation valve and is used to control the switching of the pressure compensation valve. The second control oil circuit includes a pressure oil source valve and an electro-proportional pressure reducing valve. The pressure oil source valve is connected to the output end of the variable displacement pump, and the electro-proportional pressure reducing valve is connected to the pressure oil source valve and the proportional flow distribution valve and is used to control the switching of the proportional flow distribution valve.

[0008] Preferably, the first control oil circuit includes a pressure shut-off valve and a load-sensitive valve. The pressure shut-off valve is connected to the output end of the variable pump and the load-sensitive valve, and the load-sensitive valve is connected to the output end of the variable pump and the pressure compensation valve.

[0009] Preferably, the first control oil circuit also includes a constant flow valve and an LS relief valve, wherein the constant flow valve is connected to the load-sensitive valve and the oil tank, and the LS relief valve is connected to the load-sensitive valve and the oil tank.

[0010] Preferably, the pressure oil source valve includes a pressure reducing valve and a pressure relief valve. The oil inlet of the pressure reducing valve is connected to the output end of the variable pump, the oil outlet of the pressure reducing valve is connected to a check valve and then to an electro-proportional pressure reducing valve, the oil outlet of the pressure reducing valve is also connected to the oil inlet of the pressure relief valve, and the oil outlet of the pressure relief valve is connected to the oil tank.

[0011] Preferably, two sets of electro-proportional pressure reducing valves are provided, both connected to the pressure oil source valve and respectively connected to the two ends of the control switching of the proportional flow distribution valve, used to control the proportional flow distribution valve to switch to the left or right.

[0012] As a preferred option, the proportional flow distribution valve adopts a three-position six-way valve with the center position closed. The left and right positions are controlled by two electro-proportional pressure reducing valves, which also control the forward and reverse rotation of the fan motor.

[0013] Preferably, the fan motor is a fixed-displacement motor, and the output of the fan motor is connected to the cooling fan to drive the cooling fan to rotate.

[0014] Preferably, two sets of overload replenishing valves are provided, which are respectively installed on the two oil supply lines connected to the fan motor and the proportional flow distribution valve. Each overload replenishing valve includes an overload valve and a replenishing valve. The oil inlet of the overload valve and the oil outlet of the replenishing valve are both connected to the proportional flow distribution valve. The oil outlet of the overload valve and the oil inlet of the replenishing valve are interconnected and return to the oil tank.

[0015] Preferably, it also includes multiple temperature sensors for detecting coolant temperature, torque converter oil temperature, and intercooler temperature.

[0016] The effects provided in the utility model description are merely those of the embodiments, and not all the effects of the utility model. The above technical solution has the following advantages:

[0017] 1. The cooling fan of this utility model is decoupled from the engine. The speed of the cooling fan is adjusted by the temperature information collected by the temperature sensor. At the same time, a variable pump is used to supply oil on demand, which eliminates flow loss, saves more energy, and has good economic performance.

[0018] 2. This utility model controls the proportional flow distribution valve to gradually reduce the opening until it reverses by setting two sets of electro-proportional pressure reducing valves, thereby controlling the cooling fan to reverse. By changing the current, a smooth reversal is achieved to reduce hydraulic shock and extend the service life of the system.

[0019] 3. By setting up a pressure shut-off valve and an overload replenishing valve, this utility model can prevent the system pressure from becoming too high, thereby protecting the hydraulic components. Attached Figure Description

[0020] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0021] Figure 1 This is a schematic diagram of the hydraulic system according to an embodiment of the present utility model;

[0022] Figure 2 This is a schematic diagram illustrating the connection between the variable pump, pressure shut-off valve, and load-sensitive valve in an embodiment of this utility model.

[0023] Figure 3 This is a schematic diagram of the pressure oil source valve according to an embodiment of the present utility model;

[0024] Figure 4 This is a schematic diagram illustrating the connection principle of the proportional flow distribution valve and the pressure compensation valve in an embodiment of this utility model.

[0025] Figure 5 This is an enlarged schematic diagram of the overload replenishing valve according to an embodiment of the present invention;

[0026] Figure 6 This is an enlarged schematic diagram of the principle of the electro-proportional pressure reducing valve according to an embodiment of this utility model.

[0027] In the diagram, 1 is a variable pump; 2 is an oil tank; 3 is a cooling oil supply circuit; 4 is the first control oil circuit; 5 is the second control oil circuit; 6 is a fan motor; 31 is a proportional flow distribution valve; 32 is a pressure compensation valve; 33 is an overload replenishing valve; 41 is a pressure shut-off valve; 42 is a load-sensitive valve; 43 is a constant flow valve; 44 is an LS relief valve; 51 is a pressure oil source valve; 52 is an electro-proportional pressure reducing valve; 331 is an overload valve; 332 is a replenishing valve; 511 is a pressure reducing valve; 512 is a pressure relief valve; and 513 is a check valve. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] like Figures 1-6As shown, this utility model provides a technical solution:

[0030] An independent cooling system for a loader includes a variable displacement pump 1 and an oil tank 2. The variable displacement pump 1 is driven by a motor. The input end of the variable displacement pump 1 is connected to the oil tank 2, and the output end of the variable displacement pump 1 is connected to a pilot control oil circuit and a cooling oil supply circuit 3. The pilot control oil circuit is used for control oil and is a low-flow oil circuit. Figure 1 The dashed line indicates that oil supply line 3 is the main oil supply line for powering the cooling fan. Figure 1 The pilot control oil circuit, represented by solid lines, includes a first control oil circuit 4 and a second control oil circuit 5. The cooling oil supply circuit 3 includes a proportional flow distribution valve 31, a pressure compensation valve 32, and an overload replenishing valve 33. The proportional flow distribution valve 31 is connected to the output end of the variable pump 1 and the pressure compensation valve 32. The overload replenishing valve 33 is connected to the proportional flow distribution valve 31 and the fan motor 6. The first control oil circuit 4 is connected to the pressure compensation valve 32 and is used to control the switching of the pressure compensation valve 32. The second control oil circuit 5 includes a pressure oil source valve 51 and an electro-proportional pressure reducing valve 52. The pressure oil source valve 51 is connected to the output end of the variable pump 1. The electro-proportional pressure reducing valve 52 is connected to the pressure oil source valve 51 and the proportional flow distribution valve 31 and is used to control the switching of the proportional flow distribution valve 31.

[0031] In an optional embodiment, the first control oil circuit 4 includes a pressure shut-off valve 41 and a load-sensitive valve 42. The pressure shut-off valve 41 connects the output of the variable pump 1 and the load-sensitive valve 42. The load-sensitive valve 42 connects the output of the variable pump 1 and the pressure compensation valve 32. The load-sensitive valve 42 is set to control a differential pressure of 20 bar. The spring end is connected to the load through the LS feedback oil circuit, and the non-spring end is connected to the pump outlet. When the changing oil pressure difference is less than 20 bar, the spring pushes the load-sensitive valve 42 to the right position, the swashplate angle of the variable pump 1 increases, and the pump displacement increases. When it is greater than 20 bar, the spring force overcomes the load-sensitive valve 42 to the left position, the swashplate angle of the variable pump 1 decreases, and the pump displacement decreases. The adjustment of the load-sensitive valve 42 is a dynamic process, with the valve stem constantly jumping to maintain a value of 20 bar. The pressure remains unchanged, thus supplying the flow of the working system on demand. The spring pressure of the pressure shut-off valve 41 is set to 24MPa. When the outlet pressure of the variable pump 1 is greater than 24MPa, the pressure overcomes the spring force and pushes the load-sensitive valve 42 to the left position. The swashplate angle of the variable pump 1 decreases, and the displacement of the variable pump 1 is reduced to the minimum displacement. The output flow only meets the internal leakage of the system and the internal leakage of the pump itself.

[0032] In an optional embodiment, the first control oil circuit 4 further includes a constant flow valve 43 and an LS relief valve 44. The constant flow valve 43 is connected to the load-sensitive valve 42 and the oil tank 2, and the LS relief valve 44 is connected to the load-sensitive valve 42 and the oil tank 2. The constant flow valve 43 is used to relieve pressure on the LS signal when the system is not working, preventing the pump from being in a high-pressure state for a long time. The LS relief valve 44 acts as a safety valve to limit the maximum pressure of the system. The pressure shut-off valve 41 acts as a primary safety valve to limit the maximum pressure of the system. The LS relief valve 44 acts as a secondary safety valve, further improving the safety of the system.

[0033] In one optional embodiment, the pressure oil source valve 51 includes a pressure reducing valve 511 and a pressure relief valve 512. The inlet of the pressure reducing valve 511 is connected to the output end of the variable pump 1, and the outlet of the pressure reducing valve 511 is connected to the check valve 513 and then to the electro-proportional pressure reducing valve 52, for reducing the pressure of high-pressure oil to low pressure and supplying it to the electro-proportional pressure reducing valve 52. The outlet of the pressure reducing valve 511 is also connected to the inlet of the pressure relief valve 512, and the outlet of the pressure relief valve 512 is connected to the oil tank 2, for limiting the maximum pressure of the control second control oil circuit 5. In another embodiment, an accumulator is also included, which is disposed between the check valve 513 and the electro-proportional pressure reducing valve 52, for temporary pilot oil in case of engine shutdown or engine failure.

[0034] In an optional embodiment, the electro-proportional pressure reducing valve 52 controls the opening area of ​​the valve core of the proportional flow distribution valve 31 through pilot oil. Two electro-proportional pressure reducing valves 52 are provided, one for controlling forward rotation and the other for controlling reverse rotation. Both electro-proportional pressure reducing valves 52 are connected to the pressure oil source valve 51 and are respectively connected to the two ends of the proportional flow distribution valve 31 for controlling the proportional flow distribution valve 31 to switch to the left or right.

[0035] In an optional embodiment, the proportional flow distribution valve 31 is a three-position six-way valve with the center position closed. It is controlled by two electro-proportional pressure reducing valves 52 to switch left and right positions and control the forward and reverse rotation of the fan motor 6. When switching, the current of the electro-proportional pressure reducing valve 52 controlling the forward rotation gradually decreases, the opening of the proportional flow distribution valve 31 decreases, and the fan motor 6 decelerates. When the speed of the fan motor 6 reaches 0, the electro-proportional pressure reducing valve 52 controlling the reverse rotation is energized, the proportional flow distribution valve 31 switches, and the fan motor 6 reverses, achieving a smooth switching.

[0036] In an optional embodiment, the fan motor 6 is configured as a fixed-displacement motor, and the output of the fan motor 6 is connected to a cooling fan to drive the cooling fan to rotate.

[0037] In an optional embodiment, two sets of overload replenishing valves 33 are provided, respectively located on the two oil supply lines connecting the fan motor 6 and the proportional flow distribution valve 31. Each overload replenishing valve 33 includes an overload valve 331 and a replenishing valve 332. The oil inlet of the overload valve 331 and the oil outlet of the replenishing valve 332 are both connected to the proportional flow distribution valve 31. The oil outlet of the overload valve 331 and the oil inlet of the replenishing valve 332 are interconnected and return to the oil tank 2. The overload replenishing valve 33 can effectively absorb the impact in the system and ensure the service life of the fan motor 6.

[0038] In an optional embodiment, a plurality of temperature sensors are also included for detecting coolant temperature, torque converter oil temperature, and intercooler temperature, respectively.

[0039] In an optional embodiment, a controller is also included, connected to electrical appliances such as a power supply, various temperature sensors, an electro-proportional pressure reducing valve 52, and a motor, for receiving detected temperature values ​​and controlling the normal operation of the system.

[0040] Working principle: When the detected coolant temperature, torque converter oil temperature, and intercooler air temperature are low, the fan speed is low, enabling rapid engine warm-up. When the detected coolant temperature, torque converter oil temperature, and intercooler air temperature are too high, the current input to the electro-proportional pressure reducing valve 52 increases, the output pressure of the electro-proportional pressure reducing valve 52 increases, which in turn causes the opening of the proportional flow distribution valve 31 to widen, increasing the oil flow and thus increasing the fan speed. When reversal is required, it can be automatically reversed at a timed interval or manually controlled, without the need for manual cleaning of the radiator. Specifically, the current controlling the forward rotation of the electro-proportional pressure reducing valve 52 gradually decreases, the opening of the proportional flow distribution valve 31 decreases, and the fan motor 6 decelerates. When the speed of the fan motor 6 reaches 0, the electro-proportional pressure reducing valve 52 controlling the reverse rotation is energized, the proportional flow distribution valve 31 reverses, and the fan motor 6 reverses.

[0041] Any aspects of this utility model that are not detailed herein are conventional technical means known to those skilled in the art.

[0042] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "multiple" means two or more unless otherwise explicitly specified.

[0044] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

[0045] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An independent cooling system for a loader, characterized in that, It includes a variable pump (1) and an oil tank (2). The variable pump (1) is driven by a motor. The input end of the variable pump (1) is connected to the oil tank (2). The output end of the variable pump (1) is connected to the pilot control oil circuit and the heat dissipation oil supply oil circuit (3). The pilot control oil circuit includes a first control oil circuit (4) and a second control oil circuit (5). The heat dissipation oil supply circuit (3) includes a proportional flow distribution valve (31), a pressure compensation valve (32) and an overload replenishment valve (33). The proportional flow distribution valve (31) is connected to the output end of the variable pump (1) and the pressure compensation valve (32). The overload replenishment valve (33) is connected to the proportional flow distribution valve (31) and the fan motor (6). The first control oil circuit (4) is connected to the pressure compensation valve (32) for controlling the switching of the pressure compensation valve (32); The second control oil circuit (5) includes a pressure oil source valve (51) and an electro-proportional pressure reducing valve (52). The pressure oil source valve (51) is connected to the output end of the variable pump (1), and the electro-proportional pressure reducing valve (52) is connected to the pressure oil source valve (51) and the proportional flow distribution valve (31) to control the switching of the proportional flow distribution valve (31).

2. The independent cooling system for a loader according to claim 1, characterized in that: The first control oil circuit (4) includes a pressure shut-off valve (41) and a load-sensitive valve (42). The pressure shut-off valve (41) is connected to the output end of the variable pump (1) and the load-sensitive valve (42). The load-sensitive valve (42) is connected to the output end of the variable pump (1) and the pressure compensation valve (32).

3. The independent cooling system for a loader according to claim 2, characterized in that: The first control oil circuit (4) also includes a constant flow valve (43) and an LS relief valve (44). The constant flow valve (43) is connected to the load-sensitive valve (42) and the oil tank (2), and the LS relief valve (44) is connected to the load-sensitive valve (42) and the oil tank (2).

4. The independent cooling system for a loader according to claim 3, characterized in that: The pressure oil source valve (51) includes a pressure reducing valve (511) and a pressure relief valve (512). The oil inlet of the pressure reducing valve (511) is connected to the output end of the variable pump (1). The oil outlet of the pressure reducing valve (511) is connected to the check valve (513) and then to the electro-proportional pressure reducing valve (52). The oil outlet of the pressure reducing valve (511) is also connected to the oil inlet of the pressure relief valve (512). The oil outlet of the pressure relief valve (512) is connected to the oil tank (2).

5. The independent cooling system for a loader according to claim 4, characterized in that: Two sets of electro-proportional pressure reducing valves (52) are provided, both of which are connected to the pressure oil source valve (51) and are respectively connected to the two ends of the control switching of the proportional flow distribution valve (31) to control the proportional flow distribution valve (31) to switch to the left or right.

6. The independent cooling system for a loader according to claim 5, characterized in that: The proportional flow distribution valve (31) is a three-position six-way valve with the core closed in the middle position. It controls the left and right switching through two electric proportional pressure reducing valves (52) and controls the forward and reverse rotation of the fan motor (6).

7. The independent cooling system for a loader according to claim 6, characterized in that: The fan motor (6) is set as a fixed motor, and the output end of the fan motor (6) is connected to the cooling fan to drive the cooling fan to rotate.

8. The independent cooling system for a loader according to claim 6, characterized in that: Two sets of overload replenishing valves (33) are provided, which are respectively set on the two oil supply lines connected to the fan motor (6) and the proportional flow distribution valve (31). Each overload replenishing valve (33) includes an overload valve (331) and a replenishing valve (332). The oil inlet of the overload valve (331) and the oil outlet of the replenishing valve (332) are connected to the proportional flow distribution valve (31). The oil outlet of the overload valve (331) and the oil inlet of the replenishing valve (332) are connected to each other and return to the oil tank (2).

9. The independent cooling system for a loader according to claim 1, characterized in that: It also includes multiple temperature sensors, which are used to detect the coolant temperature, torque converter oil temperature, and intercooler temperature, respectively.

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