Hydraulic motor flush cooling method

Abstract

The application discloses a hydraulic motor flushing cooling method, S1) judging whether a closed hydraulic circuit is running, if not, continue to judge, if yes, execute the next step; S2) starting a hydraulic pump, providing cooling oil for the hydraulic motor, and starting a proportional flow valve, the cooling oil enters the flushing port of the hydraulic motor through the proportional flow valve, and the hydraulic motor starts to be cooled; S3) monitoring the pressure sensor value in real time, if the pressure sensor value reaches a set value, it is considered that too much oil passes through the corresponding proportional flow valve, and the opening of the corresponding proportional flow valve is reduced; S4) if the pressure sensor value is less than the set value, the original opening of the corresponding proportional flow valve is maintained unchanged; S5) when the closed hydraulic circuit stops working, the hydraulic motor stops working, the hydraulic pump is closed, and the proportional flow valve is closed. The application can solve the technical problems that the existing hydraulic motor cooling method has poor heat dissipation effect and cannot meet the heat dissipation cooling demand under severe working conditions.

Description

Technical Field

[0001] This application relates to the field of railway maintenance machinery technology, and in particular to a method for flushing and cooling hydraulic motors used in the hydraulic travel of large railway maintenance machinery. Background Technology

[0002] Hydraulic systems can generally be divided into open circuits and closed circuits. An open circuit refers to a system where the hydraulic pump draws oil from the tank, drives the actuator (such as a hydraulic cylinder or motor) through hydraulic valves, and then returns the oil to the tank. The tank is connected to the atmosphere via an air filter to balance changes in oil volume within the piping system and actuators. Overall, the system is open and connected to the atmosphere. The advantages of an open circuit are its simple structure, lower requirements for the hydraulic pump compared to a closed circuit, lower cost, applicability to various actuators such as cylinders and motors, and better system adaptability. Therefore, it has wide applications in both industrial and engineering machinery sectors, accounting for two-thirds of all hydraulic systems. A closed circuit refers to a system where the hydraulic pump's suction line is connected to the actuator's return line. In this case, the hydraulic pump's output oil directly enters the actuator, and the actuator's return oil directly enters the hydraulic pump's inlet; the oil in the system is closed. Because there is no hydraulic tank to balance the changes in oil volume in the system, the actuators in a closed system are often hydraulic motors, with the same oil inlet and return rates.

[0003] In the field of hydraulic travel control, closed-loop hydraulic systems are generally used. In these systems, a closed-loop pump drives the vehicle's movement via a hydraulic motor, and multiple hydraulic motors often operate simultaneously. However, closed-loop hydraulic systems suffer from significant heat generation and difficulty in heat dissipation. Prolonged travel causes severe overheating of the hydraulic motors, especially the travel hydraulic motors, which operate under harsh conditions. Traditional closed-loop systems rely on an integrated oil pump and flushing valve for oil cooling, which is inefficient and ineffective, failing to meet the cooling requirements of the hydraulic motors under harsh conditions. Therefore, timely and efficient cooling is essential for ensuring normal travel.

[0004] There are generally two existing technical solutions for cooling and heat dissipation of hydraulic motors: The first approach is to use the built-in replenishing pump and flushing valve of the closed-loop hydraulic system to cool the hydraulic circuit. The problems with this approach are: 1. The replenishing pump itself has a small flow rate, resulting in poor cooling for hydraulic motors that generate a lot of heat under harsh operating conditions; 2. The flushing valve of the closed-loop hydraulic system drains a portion of the oil from the main oil circuit into the cooler, without directly cooling the heavily heated hydraulic motor housing, resulting in poor cooling performance.

[0005] The second approach is to use a separate cooling circuit to dissipate heat. However, since it only cools the oil in the hydraulic tank and does not directly cool and flush the hot hydraulic motor housing, the cooling effect is still not good.

[0006] Among the existing technologies, the following documents are most similar to this application: Document 1 is a Chinese invention application filed by Wuxi Zuantong Engineering Machinery Co., Ltd. on July 26, 2017, and published on September 17, 2024, with publication number CN107191438A. This application discloses a closed-loop system cooling circuit for high-power operation, including a hydraulic oil tank, a closed-loop pump, a hydraulic motor, a cooler, and a flushing valve. The suction port S and drain port L of the closed-loop pump are connected to the hydraulic oil tank, and the A and B ports of the closed-loop pump are connected to the A and B ports of the hydraulic motor, respectively. The first drain port L1 of the hydraulic motor is connected to the hydraulic oil tank, and the A1 and B1 ports of the hydraulic motor are connected to the A and B ports of the flushing valve, respectively. The T port of the flushing valve is connected to the inlet port of the cooler, and the outlet port of the cooler is connected to the second drain port L2 of the hydraulic motor. This application employs a simple, ingenious, and reasonable cooling circuit, which can effectively control the temperature of the hydraulic motor during continuous high-power operation, suppressing damage to the hydraulic motor caused by excessive temperature. This application is an improvement on the traditional closed-loop cooling circuit of oil replenishment pump + flushing valve, without setting up an independent flushing and cooling circuit for each hydraulic motor.

[0007] Document 2 is a Chinese invention application filed by Ningbo Zhenhai Xiang'ao Electromechanical Co., Ltd. on November 16, 2016, and published on September 17, 2024, with publication number CN106762897A. This application discloses a flushing valve, including a valve block, a directional valve core, a return spring, a pressure relief valve core, a pressure relief valve sleeve, an adjusting screw, and an adjusting nut. The valve block internally has a directional valve chamber, a low-pressure oil passage, a high-pressure oil passage, and a pressure relief valve chamber. The low-pressure and high-pressure oil passages have low-pressure oil ports, high-pressure oil ports, and flushing oil ports on their surfaces. The directional valve core is located in the directional valve chamber, and the pressure relief valve core is located in the pressure relief valve chamber. This flushing valve has the advantage of a wide range of steplessly adjustable flushing flow rates, eliminating the need to change the flushing flow rate by replacing the flushing valve, and can be applied to hydraulic motors of different specifications. This application mainly focuses on the adjustable flow rate of the flushing valve and does not involve a complete hydraulic motor cooling flushing circuit.

[0008] Document 3 is a Chinese utility model patent applied for by Baoji Petroleum Machinery Co., Ltd. and Baoji Baoshi Special Vehicle Co., Ltd. on November 18, 2015, and published on September 17, 2024, with publication number CN205663665U. This patent discloses a closed-loop hydraulic system for a special vehicle with an open-loop pump. It includes an open-loop oil pump and a hydraulic oil tank. The hydraulic oil tank contains a replenishing valve. The outlet of the open-loop oil pump is connected to the inlet of a hydraulic motor via a high-pressure pipeline. The outlet of the hydraulic motor is connected to one end of the replenishing valve via a low-pressure pipeline. The other end of the replenishing valve is connected to the suction port of the open-loop oil pump. A flushing circuit is provided between the open-loop oil pump, the hydraulic motor, and the hydraulic oil tank. The patented open-loop oil pump with load-sensitive variable ensures its flow rate and pressure are matched to the hydraulic system requirements, minimizing wasted power loss. A specially designed replenishing valve connects the open-loop pump to the hydraulic motor, creating a closed-loop circulation system that significantly reduces overall system heat generation, decreases the hydraulic oil tank size, and lessens the burden on the cooling system. However, this patent does not include a dedicated pump for motor cooling and flushing, resulting in ineffective motor cooling.

[0009] Therefore, existing technologies either lack a separate cooling flushing circuit, or lack a flushing and cooling scheme for multiple motors, or lack automatic flow distribution for flushing and cooling multiple motors, and the flushing and cooling circuit does not consider energy-saving technologies, resulting in poor cooling and heat dissipation effects for hydraulic motors. Summary of the Invention

[0010] In view of this, the purpose of this application is to provide a hydraulic motor flushing and cooling method to solve the technical problem that the existing hydraulic motor cooling methods have poor heat dissipation effect and cannot meet the heat dissipation and cooling requirements under harsh working conditions.

[0011] To achieve the aforementioned objectives, this application specifically provides a technical implementation scheme for a hydraulic motor flushing and cooling method, providing flushing and cooling for a closed hydraulic circuit. The closed hydraulic circuit includes a hydraulic motor assembly, which comprises several hydraulic motors. The flushing and cooling device includes a hydraulic pump and a valve assembly, the valve assembly including a proportional flow valve assembly. The proportional flow valve assembly includes proportional flow valves corresponding to the number of hydraulic motors, and a pressure sensor is connected to the outlet of each proportional flow valve. The method includes the following steps: S1) Determine if the closed hydraulic circuit is running. If not, continue to determine if it is running. If it is running, proceed to the next step. S2) Start the hydraulic pump to provide cooling oil to the hydraulic motor, and start the proportional flow valve. The cooling oil enters the flushing port of the hydraulic motor through the proportional flow valve to begin cooling the hydraulic motor. S3) Monitor the value of the pressure sensor in real time. If the value of a pressure sensor reaches the set value, it is considered that too much oil is passing through the corresponding proportional flow valve, and the opening of the corresponding proportional flow valve is reduced. S4) If the pressure sensor value is less than the set value, the original opening of the corresponding proportional flow valve shall be maintained unchanged. S5) When the closed hydraulic circuit stops working and the hydraulic motor stops working, the hydraulic pump is turned off, and the proportional flow valve is closed at the same time.

[0012] Furthermore, the flushing and cooling device also includes a filter connected between the hydraulic pump and the valve assembly. The filter filters the hydraulic pump oil before supplying it to the valve assembly, ensuring the cleanliness of the oil and preventing impurities in the oil from causing valve jamming or hydraulic motor wear.

[0013] Furthermore, the valve assembly also includes a main circuit check valve, with the inlet of the main circuit check valve connected to the filter and the outlet of the main circuit check valve connected to the inlet of the proportional flow valve, thereby preventing oil backflow.

[0014] Furthermore, the flushing and cooling device also includes a cooler, connecting the oil outlet of the proportional flow valve to the flushing port of the hydraulic motor, and connecting the oil drain port of the hydraulic motor to the oil tank through the cooler. The hydraulic fluid flows from the hydraulic pump sequentially through the filter, the main circuit check valve, and the proportional flow valve to directly flush the housing of the hydraulic motor assembly. After being cooled by the cooler, it flows back to the oil tank, forming an independent hydraulic flushing and cooling circuit corresponding to the hydraulic motor.

[0015] Furthermore, when the closed-loop hydraulic circuit stops operating, the hydraulic flushing and cooling circuit also stops operating. When the closed-loop hydraulic circuit starts operating, the hydraulic pump starts, and simultaneously the proportional flow valve starts, providing cooling and flushing oil to the hydraulic motor.

[0016] Furthermore, the valve assembly also includes a check valve assembly, which comprises check valves corresponding to the number of hydraulic motors. The inlet of the check valve is connected to the outlet of a proportional flow valve, and the outlet of the check valve is connected to an oil tank. The flushing flow rate of the corresponding hydraulic motor is adjusted by the proportional flow valve. The check valve ensures that the flushing pressure of the corresponding hydraulic motor does not exceed its set value; if the set value is exceeded, excess oil flows back to the oil tank through the return port of the valve assembly.

[0017] Furthermore, when the proportional flow valve is closed, the hydraulic pump's displacement is zero, and there is no oil output. When the proportional flow valve is open, the hydraulic pump's displacement increases, providing cooling and flushing oil to the hydraulic motor, which is then cooled by the cooler and returned to the oil tank.

[0018] Furthermore, the flushing pressure of the hydraulic motor is monitored in real time by the pressure sensor. If the monitored pressure reaches the set value, the opening of the proportional flow valve is reduced to reduce the flushing flow and ensure that the flushing pressure fluctuates within a stable range.

[0019] Furthermore, the working ports of the plurality of hydraulic motors are connected in parallel, and the cooling flushing oil enters from the flushing port on one side of the hydraulic motor and then flows out from the flushing port on the other side of the hydraulic motor.

[0020] Furthermore, a closed-loop pump is connected in parallel between the two working ports of the hydraulic motor.

[0021] Furthermore, the hydraulic pump is a constant pressure variable pump, a load-sensitive pump, or a fixed displacement pump.

[0022] By implementing the hydraulic motor flushing and cooling method provided in this application, the following beneficial effects are achieved: (1) The hydraulic motor flushing and cooling method of this application adopts a separate cooling flushing circuit, directly flushes the motor housing and then enters the radiator, directly flushes the motor housing that is severely overheated, and greatly improves the cooling effect; (2) The hydraulic motor flushing and cooling method of this application adopts an integrated cooling valve group, which integrates multiple flow control valves, pressure sensors, check valves, etc. on one valve group. It can meet the functions of distribution, protection and control of flushing and cooling flow of multiple hydraulic motors on one integrated valve group. It has a high degree of integration and is easy to expand. It is especially suitable for flushing and cooling of multiple motors. (3) The hydraulic motor flushing and cooling method of this application can adjust the flow rate of each motor flushing circuit in real time by detecting the flushing pressure of the hydraulic motor, so as to achieve the purpose of rapid flushing and cooling of the hydraulic motor. At the same time, it can realize the real-time adjustment and automatic distribution of the flushing flow rate of each motor. (4) The hydraulic motor flushing and cooling method of this application uses a constant pressure variable pump and a proportional flow valve. The constant pressure variable pump can automatically adjust the output flow rate according to the opening of the proportional flow valve, which greatly improves the energy saving effect. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart of a specific embodiment of the hydraulic motor flushing and cooling method of this application; Figure 2 This is a schematic diagram of the structural composition of a specific embodiment of the hydraulic motor flushing and cooling device and system on which the method of this application is based; Figure 3 This is a schematic diagram of the valve group structure in a specific embodiment of the hydraulic motor flushing and cooling device and system on which the method of this application is based.

[0025] In the diagram: 1-Closed-loop pump, 2-Hydraulic motor assembly, 21-First hydraulic motor, 22-Second hydraulic motor, 23-Third hydraulic motor, 24-Fourth hydraulic motor, 3-Hydraulic pump, 4-Filter, 5-Valve assembly, 6-Main circuit check valve, 7-Proportional flow valve assembly, 71-First proportional flow valve, 72-Second proportional flow valve, 73-Third proportional flow valve, 74-Fourth proportional flow valve, 8-Pressure sensor, 81-First pressure sensor, 82-Second pressure sensor, 83-Third pressure sensor, 84-Fourth pressure sensor, 9-Check valve assembly, 91-First check valve, 92-Second check valve, 93-Third check valve, 94-Fourth check valve, 10-Cooler, 11-Oil tank, 12-Pressure test port, 20-Closed-loop hydraulic circuit. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] As attached Figure 1 To be continued Figure 3 As shown, a specific embodiment of the hydraulic motor flushing and cooling method of this application is given. The application will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] The hydraulic motor flushing and cooling method of this application is particularly suitable for flushing control of multiple hydraulic motors. The following embodiment takes the flushing of four hydraulic motors as an example for specific description.

[0029] Example 1 As attached Figure 1As shown, an embodiment of the hydraulic motor flushing and cooling method of this application provides flushing and cooling for a closed hydraulic circuit 20. The closed hydraulic circuit 20 includes a hydraulic motor assembly 2, which includes a plurality of hydraulic motors. The flushing and cooling device includes a hydraulic pump 3 and a valve assembly 5, which includes a proportional flow valve assembly 7. The proportional flow valve assembly 7 includes proportional flow valves corresponding to the number of hydraulic motors, and a pressure sensor 8 is connected to the outlet of each proportional flow valve. The method specifically includes the following steps: S1) Determine whether the closed hydraulic circuit 20 is running, that is, whether the hydraulic motor has started working. If not, continue to determine; if yes, proceed to the next step. S2) Start the hydraulic pump 3 to provide cooling oil to the hydraulic motor and start the four proportional flow valves (first proportional flow valve 71, second proportional flow valve 72, third proportional flow valve 73 and fourth proportional flow valve 74, and assign an initial value to the opening of the four proportional flow valves). At this time, the cooling oil enters the flushing port of the hydraulic motor through the proportional flow valves and begins to provide cooling for the hydraulic motor. S3) Real-time monitoring of the values ​​of pressure sensors 8 (first pressure sensor 81, second pressure sensor 82, third pressure sensor 83 and fourth pressure sensor 84). If the value of a certain pressure sensor 8 reaches the set value, it is considered that too much oil is passing through the corresponding proportional flow valve. In order to protect the hydraulic motor, the opening of the corresponding proportional flow valve is appropriately reduced. S4) If the value of pressure sensor 8 is less than the set value, the original opening of the corresponding proportional flow valve (first proportional flow valve 71, second proportional flow valve 72, third proportional flow valve 73 and fourth proportional flow valve 74) remains unchanged. S5) When the closed hydraulic circuit 20 stops working and the hydraulic motor stops working, the hydraulic pump 3 is turned off, and the proportional flow valve is turned off at the same time.

[0030] The flushing and cooling device also includes a filter 4, which is connected between the hydraulic pump 3 and the valve assembly 5. The filter 4 filters the oil from the hydraulic pump 3 before supplying it to the valve assembly 5 to ensure the cleanliness of the oil and prevent impurities in the oil from causing valve jamming or wear on the hydraulic motor.

[0031] Valve assembly 5 also includes a main circuit check valve 6, which connects the oil inlet of the main circuit check valve 6 to the filter 4 and the oil outlet of the main circuit check valve 6 to the oil inlet of the proportional flow valve, thereby preventing oil backflow.

[0032] The flushing and cooling device also includes a cooler 10, which connects the outlet of the proportional flow valve to the flushing port of the hydraulic motor, and connects the drain port of the hydraulic motor to the oil tank 11 through the cooler 10. The oil flows from the hydraulic pump 3 through the filter 4, the main circuit check valve 6, and the proportional flow valve in sequence to directly flush the housing of the hydraulic motor assembly 2. After being cooled by the cooler 10, it flows back to the oil tank 11, forming an independent hydraulic flushing and cooling circuit corresponding to the hydraulic motor.

[0033] When the closed hydraulic circuit 20 stops operating, the hydraulic flushing and cooling circuit also stops operating. When the closed hydraulic circuit 20 starts operating, the hydraulic pump 3 starts, and at the same time, the proportional flow valve starts to provide cooling and flushing oil to the hydraulic motor.

[0034] Valve assembly 5 also includes a check valve assembly 9, which comprises check valves (first check valve 91, second check valve 92, third check valve 93, and fourth check valve 94) corresponding to the number of hydraulic motors. The inlet of each check valve is connected to the outlet of a proportional flow valve, and the outlet of each check valve is connected to the oil tank 11. The flushing flow rate of the corresponding hydraulic motor is adjusted by the proportional flow valve. The check valves ensure that the flushing pressure of the corresponding hydraulic motor does not exceed the set value of the check valve; if the set value is exceeded, the excess oil flows back to the oil tank 11 through the return port of valve assembly 5.

[0035] When the proportional flow valve is closed, the hydraulic pump 3 has zero displacement and no oil output. When the proportional flow valve is open, the hydraulic pump 3 has increased displacement, providing cooling and flushing oil for the hydraulic motor. The oil is then cooled by the cooler 10 and returned to the oil tank 11.

[0036] The flushing pressure of the hydraulic motor is monitored in real time by pressure sensor 8. If the monitored pressure reaches the set value, the opening of the proportional flow valve is reduced to reduce the flushing flow and ensure that the flushing pressure fluctuates within a stable range.

[0037] Several hydraulic motors have their working ports connected in parallel. Cooling and flushing oil enters from one flushing port of the hydraulic motor and exits from the other, ensuring that the flushing oil fills the entire housing of the hydraulic motor, thereby removing the heat generated by the hydraulic motor and achieving the best heat dissipation effect. A closed-loop pump 1 is connected in parallel between the two working ports of the hydraulic motors. The hydraulic pump 3 is further configured as a constant pressure variable pump, a load-sensitive pump, or a fixed displacement pump.

[0038] The above embodiment describes the flushing and cooling scheme using four hydraulic motors as an example. The number of flushing hydraulic motors can be increased or decreased as needed, simply by adding or removing the proportional flow valve, pressure sensor, and check valve 9 from the integrated flushing and cooling valve group 5. From a cost-saving perspective, the proportional flow valve in the integrated flushing and cooling valve group 5 can be replaced with a manual throttle valve, allowing manual setting of the flushing flow rate for each hydraulic motor. Furthermore, from an energy-saving perspective, the hydraulic pump 3 providing the flushing and cooling oil source in this embodiment is a constant-pressure variable pump, but a load-sensitive pump can also be used; if energy saving is not a concern, a fixed-displacement pump can also be used. All these alternative solutions still fall within the scope of this application.

[0039] This embodiment discloses a technical solution for a hydraulic motor flushing and cooling method. The solution establishes an independent hydraulic motor cooling and flushing circuit, equipped with a dedicated constant-pressure variable pump to provide oil for the flushing and cooling circuit. After filtration, the oil enters an integrated flushing and cooling control valve group 5, which then flushes and cools the housings of all operating hydraulic motors, carrying away the heat dissipated by the hydraulic motors through the oil. The oil finally flows back to the oil tank 11 through a cooler 10. Because the hydraulic motors are directly flushed, the cooling efficiency is high. This solution integrates multiple flow control valves (i.e., proportional flow valves), pressure sensors, check valves, etc., on a single control valve group 5, exhibiting high integration and suitability for expansion, making it particularly suitable for flushing and cooling multiple hydraulic motors. Simultaneously, the flow rate of each hydraulic motor flushing circuit can be adjusted in real time by detecting the flushing pressure of the hydraulic motor housing, thereby achieving the purpose of flushing and cooling the hydraulic motors.

[0040] Example 2 As attached Figure 2 As shown, an embodiment of the hydraulic motor flushing and cooling device based on the method described in Embodiment 1 of this application is illustrated. The flushing and cooling device is connected to a closed hydraulic circuit 20 and specifically includes: a hydraulic pump 3, a filter 4, a valve assembly 5, and a cooler 10. The closed hydraulic circuit 20 includes a hydraulic motor assembly 2. The hydraulic pump 3 is connected to the filter 4, the filter 4 is connected to the valve assembly 5, the valve assembly 5 is connected to the hydraulic motor assembly 2, and the cooler 10 is connected to the hydraulic motor assembly 2. The hydraulic pump 3 provides oil to the flushing and cooling device. The oil flows sequentially through the filter 4 and the valve assembly 5 to directly flush the housing of the hydraulic motor assembly 2, and then flows back to the oil tank 11 after being cooled by the cooler 10. The filter 4 filters the oil from the hydraulic pump 3 before supplying it to the valve assembly 5 to ensure the cleanliness of the oil and prevent impurities in the oil from causing valve jamming or hydraulic motor wear. The hydraulic pump 3 is responsible for providing oil to the flushing and cooling circuit. To save energy, the hydraulic pump 3 further adopts a constant pressure variable pump.

[0041] Hydraulic motor assembly 2 includes several hydraulic motors (first hydraulic motor 21, second hydraulic motor 22, third hydraulic motor 23, and fourth hydraulic motor 24). Valve assembly 5 includes a main circuit check valve 6, a proportional flow valve assembly 7, and a check valve assembly 9. The proportional flow valve assembly 7 includes proportional flow valves corresponding to the number of hydraulic motors (first proportional flow valve 71, second proportional flow valve 72, third proportional flow valve 73, and fourth proportional flow valve 74). The check valve assembly 9 includes check valves corresponding to the number of hydraulic motors (first check valve 91, second check valve 92, third check valve 93, and fourth check valve 94). The inlet of the main circuit check valve 6 is connected to the filter 4, and the outlet of the main circuit check valve 6 is connected to the inlet of the proportional flow valve. The outlet of the proportional flow valve is connected to the flushing port of the hydraulic motor, and the drain port of the hydraulic motor is connected to the oil tank 11 through the cooler 10. The inlet of the check valve is connected to the outlet of the proportional flow valve, the outlet of the check valve is connected to the oil tank 11, and the outlet of the proportional flow valve is also equipped with a pressure test port 12.

[0042] The closed-loop pump 1 and hydraulic motors 21-24 form a closed-loop hydraulic circuit 20. To address the heat dissipation issue of the hydraulic motors in the closed-loop system, an independent hydraulic flushing and cooling circuit is configured. This circuit mainly consists of a hydraulic pump 3, a filter 4, an integrated flushing and cooling valve assembly 5, and a cooler 10. Oil flows from the hydraulic pump 3 sequentially through the filter 4, the main circuit check valve 6, the proportional flow valve, the hydraulic motor, and the cooler 10, returning to the oil tank 11, forming an independent hydraulic flushing and cooling circuit corresponding to the hydraulic motor. The proportional flow valve regulates the flushing flow rate of the corresponding hydraulic motor, and the check valve ensures that the flushing pressure of the corresponding hydraulic motor does not exceed its set value. Excess oil exceeding the set value flows through the return port of valve assembly 5 (as shown in the attached diagram). Figure 3 The oil flows back to the oil tank 11 through the T port shown in the figure, and a pressure test port 12 is also provided at the oil return port.

[0043] When the closed hydraulic circuit 20 stops operating, the hydraulic flushing and cooling circuit also stops operating. When the closed hydraulic circuit 20 starts operating, the hydraulic pump 3 starts, and the proportional flow valve starts simultaneously to provide cooling flushing oil to the hydraulic motor. The outlet of the proportional flow valve is also connected to pressure sensors 8 (first pressure sensor 81, second pressure sensor 82, third pressure sensor 83, and fourth pressure sensor 84) to detect the flushing pressure of the corresponding hydraulic motor. The flushing flow rate can be adjusted in real time by regulating the opening of the proportional flow valve based on the pressure from the pressure sensors. The pressure sensors 8 monitor the flushing pressure of the hydraulic motor in real time. If the monitored pressure reaches the set value, the opening of the proportional flow valve is reduced to decrease the flushing flow rate, ensuring that the flushing pressure fluctuates within a stable range. When the proportional flow valve is closed, the displacement of the hydraulic pump 3 is zero, and there is no oil output. When the proportional flow valve is open, the displacement of the hydraulic pump 3 increases, providing cooling flushing oil to the hydraulic motor, which is then cooled by the cooler 10 and returned to the oil tank 11.

[0044] The principle of the integrated flushing and cooling valve assembly 5 is shown in the attached figure. Figure 3 As shown, in a typical embodiment of this application, valve group 5 specifically consists of a main circuit check valve 6, proportional flow valves 71, 72, 73, and 74, pressure sensors 81, 82, 83, and 84, and check valves 91, 92, 93, and 94. The flushing control of each hydraulic motor is achieved by one proportional flow valve, one pressure sensor, and one check valve. The proportional flow valve is used to adjust the flushing flow rate of each hydraulic motor, the pressure sensor is used to detect the flushing pressure of each hydraulic motor, and the check valve 9 is used to ensure that the flushing pressure of each hydraulic motor does not exceed the set value of the check valve. If the set value is exceeded, excess oil is directly returned to the oil tank 11 through the T-port of valve group 5. This embodiment can perform flushing and cooling control of four hydraulic motors. If flushing of more hydraulic motors is required, the number of proportional flow valves, pressure sensors, and check valves can be increased accordingly to expand the functionality.

[0045] The hydraulic motor flushing and cooling device described in Embodiment 2 adopts an independent motor flushing and cooling circuit, which directly flushes the hydraulic motor, resulting in good cooling effect and making it particularly suitable for flushing control of multiple motors. The flushing and cooling circuit adopts a highly integrated flushing and cooling valve group, which integrates functions such as flow regulation, pressure monitoring, and overpressure protection. The hydraulic pump 3 in the cooling circuit adopts a constant pressure variable pump, which can automatically adjust the pump displacement as needed, resulting in good energy-saving effect.

[0046] Example 3 As attached Figure 2 As shown, an embodiment of the hydraulic motor flushing and cooling system based on the method described in Embodiment 1 of this application specifically includes: a closed hydraulic circuit 20, and a hydraulic motor flushing and cooling device as described in Embodiment 1 connected to the closed hydraulic circuit 20.

[0047] The closed hydraulic circuit 20 includes a hydraulic motor assembly 2, which comprises several hydraulic motors with working ports connected in parallel. The closed hydraulic circuit 20 also includes a closed pump 1 connected in parallel between two working ports of the hydraulic motors.

[0048] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0049] In the description of this application, it should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly set on the other element or indirectly set on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0050] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application 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 limitations on this application.

[0051] 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 application, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0052] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.

[0053] By implementing the technical solution of the hydraulic motor flushing and cooling method described in the specific embodiments of this application, the following technical effects can be achieved: (1) The hydraulic motor flushing and cooling method described in the specific embodiments of this application adopts a separate cooling flushing circuit, directly flushes the motor housing and then enters the radiator, directly flushes the motor housing that is severely overheated, and greatly improves the cooling effect; (2) The hydraulic motor flushing and cooling method described in the specific embodiments of this application adopts an integrated cooling valve group, which integrates multiple flow control valves, pressure sensors, check valves, etc. on one valve group. It can meet the functions of distribution, protection, and control of flushing and cooling flow of multiple hydraulic motors on one integrated valve group. It has a high degree of integration, is easy to expand, and is particularly suitable for flushing and cooling of multiple motors. (3) The hydraulic motor flushing and cooling method described in the specific embodiments of this application can achieve the purpose of rapid flushing and cooling of the hydraulic motor by detecting the flushing pressure of the hydraulic motor and adjusting the flow rate of each motor flushing circuit in real time. At the same time, it can realize the real-time adjustment and automatic distribution of the flushing flow rate of each motor. (4) The hydraulic motor flushing and cooling method described in the specific embodiments of this application uses a constant pressure variable pump and a proportional flow valve. The constant pressure variable pump can automatically adjust the output flow rate according to the opening of the proportional flow valve, which greatly improves the energy saving effect.

[0054] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0055] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any way. Although this application has been disclosed above with reference to preferred embodiments, it is not intended to limit this application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of this application. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.

Claims

1. A method for flushing and cooling a hydraulic motor, providing flushing and cooling for a closed hydraulic circuit (20), characterized in that, The closed hydraulic circuit (20) includes a hydraulic motor assembly (2), which includes several hydraulic motors; the flushing and cooling device includes a hydraulic pump (3) and a valve assembly (5), which includes a proportional flow valve assembly (7); the proportional flow valve assembly (7) includes proportional flow valves corresponding to the number of hydraulic motors, and the outlet of the proportional flow valve is connected to a pressure sensor (8); the method includes the following steps: S1) Determine whether the closed hydraulic circuit (20) is running. If not, continue to determine. If yes, proceed to the next step. S2) Start the hydraulic pump (3) to provide cooling oil to the hydraulic motor and start the proportional flow valve. The cooling oil enters the flushing port of the hydraulic motor through the proportional flow valve and begins to provide cooling to the hydraulic motor. S3) Monitor the value of the pressure sensor (8) in real time. If the value of a certain pressure sensor (8) reaches the set value, it is considered that too much oil has passed through the corresponding proportional flow valve, and the opening of the corresponding proportional flow valve is reduced. S4) If the value of the pressure sensor (8) is less than the set value, the original opening of the corresponding proportional flow valve shall be maintained unchanged. S5) When the closed hydraulic circuit (20) stops working and the hydraulic motor stops working, the hydraulic pump (3) is turned off, and the proportional flow valve is turned off at the same time; The flushing and cooling device also includes a filter (4), which is connected between the hydraulic pump (3) and the valve group (5). The filter (4) filters the oil from the hydraulic pump (3) and supplies it to the valve group (5) to ensure the cleanliness of the oil and prevent impurities in the oil from causing valve jamming or hydraulic motor wear. The flushing and cooling device also includes a cooler (10), which connects the oil outlet of the proportional flow valve to the flushing port of the hydraulic motor and connects the oil drain port of the hydraulic motor to the oil tank (11) through the cooler (10). The oil flows from the hydraulic pump (3) through the filter (4), the main circuit check valve (6), and the proportional flow valve in sequence to directly flush the housing of the hydraulic motor assembly (2), and then flows back to the oil tank (11) after being cooled by the cooler (10), forming an independent hydraulic flushing and cooling circuit corresponding to the hydraulic motor.

2. The hydraulic motor flushing and cooling method according to claim 1, characterized in that: The valve group (5) also includes a main circuit check valve (6), the oil inlet of the main circuit check valve (6) is connected to the filter (4), and the oil outlet of the main circuit check valve (6) is connected to the oil inlet of the proportional flow valve. The main circuit check valve (6) is used to prevent oil backflow.

3. The hydraulic motor flushing and cooling method according to claim 1 or 2, characterized in that: When the closed hydraulic circuit (20) stops running, the hydraulic flushing and cooling circuit stops running; when the closed hydraulic circuit (20) starts running, the hydraulic pump (3) starts, and at the same time the proportional flow valve starts to provide cooling flushing oil to the hydraulic motor.

4. The hydraulic motor flushing and cooling method according to claim 3, characterized in that: The valve group (5) also includes a check valve group (9), which includes a check valve corresponding to the number of hydraulic motors; the oil inlet of the check valve is connected to the oil outlet of the proportional flow valve, and the oil outlet of the check valve is connected to the oil tank (11); the flushing flow of the corresponding hydraulic motor is adjusted by the proportional flow valve; the check valve is used to ensure that the flushing pressure of the corresponding hydraulic motor does not exceed the set value of the check valve; after exceeding the set value, the excess oil flows back to the oil tank (11) through the return port of the valve group (5).

5. The hydraulic motor flushing and cooling method according to claim 4, characterized in that: When the proportional flow valve is closed, the displacement of the hydraulic pump (3) is zero and there is no oil output; when the proportional flow valve is open, the displacement of the hydraulic pump (3) increases, providing cooling flushing oil for the hydraulic motor, and after being cooled by the cooler (10), it flows back to the oil tank (11).

6. The hydraulic motor flushing and cooling method according to claim 5, characterized in that: The pressure sensor (8) monitors the flushing pressure of the hydraulic motor in real time. If the monitored pressure reaches the set value, the opening of the proportional flow valve is reduced to reduce the flushing flow and ensure that the flushing pressure fluctuates within a stable range.

7. The hydraulic motor flushing and cooling method according to claim 1, 2, 4, 5 or 6, characterized in that: The working ports of the plurality of hydraulic motors are connected in parallel. Cooling and flushing oil enters from the flushing port on one side of the hydraulic motor and then flows out from the flushing port on the other side of the hydraulic motor.

8. The hydraulic motor flushing and cooling method according to claim 7, characterized in that: The closed-loop pump (1) is connected in parallel between the two working ports of the hydraulic motor.

9. The hydraulic motor flushing and cooling method according to claim 1, 2, 4, 5, 6 or 8, characterized in that: The hydraulic pump (3) is a constant pressure variable pump, a load-sensitive pump or a fixed displacement pump.

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