Hydraulic motor closed monitoring control system

Abstract

The invention discloses a closed monitoring control system for a hydraulic motor. The closed monitoring control system comprises the hydraulic motor, a main pump, an oil tank, a control loop and a monitoring module, the main pump is suitable for pumping oil in the oil tank to the hydraulic motor so that the hydraulic motor can convert hydraulic energy into mechanical energy to be output. The monitoring module is suitable for detecting the working state of the hydraulic motor, and the control loop is suitable for controlling the displacement of the main pump according to the detection result of the monitoring module. The control method has the beneficial effects that the working state of the hydraulic motor is detected, and the working state of the main pump is controlled according to the detection result, so that when the hydraulic motor is abnormal, the output rotating speed of the hydraulic motor can be reduced in time or the hydraulic motor is directly shut down, and the operation safety of the hydraulic motor can be effectively guaranteed.

Description

Technical Field

[0001] The present application relates to the field of hydraulic technology, and in particular to a closed monitoring and control system for a hydraulic motor. Background Art

[0002] When the hydraulic transmission system is working, it often needs a hydraulic motor as the driving source of the entire system to achieve transmission. Since the working environment of the hydraulic transmission system is generally harsh, when the system is abnormal, the hydraulic motor may have been damaged, especially for the more expensive high-torque hydraulic motor, which will cause great economic losses.

[0003] Based on the working environment of the hydraulic system, the existing hydraulic system has relatively simple monitoring measures for the hydraulic motor, which generally only directly monitors the temperature and speed of the hydraulic motor. However, it is unable to monitor the internal wear of the hydraulic motor, and when the temperature of the hydraulic motor is abnormal, it is unable to achieve temperature control and can only issue an alarm. Summary of the invention

[0004] One of the purposes of the present application is to provide a hydraulic motor closed monitoring and control system that can solve at least one of the defects in the above-mentioned background technology.

[0005] In order to achieve at least one of the above-mentioned purposes, the technical solution adopted in the present application is: a closed monitoring and control system of a hydraulic motor, comprising a hydraulic motor, a main pump, an oil tank, a control circuit and a monitoring module; the main pump is suitable for pumping the oil in the oil tank to the hydraulic motor; the monitoring module is suitable for detecting the working state of the hydraulic motor, and the control circuit is suitable for controlling the displacement of the main pump according to the detection result of the monitoring module, thereby controlling the output flow of the hydraulic motor.

[0006] Preferably, the hydraulic motor closed monitoring and control system further comprises a cooling circuit, and the cooling circuit is suitable for outputting flushing oil to the hydraulic motor for cooling according to the temperature detection result of the monitoring module.

[0007] Preferably, the monitoring module includes a temperature sensor, and the cooling circuit includes a secondary pump and a flow control valve; the temperature sensor is suitable for detecting the working temperature of the hydraulic motor; the driving end of the secondary pump is transmission-connected to the main pump, the input end of the secondary pump is connected to the oil tank, and the output end of the secondary pump extends to the position of the hydraulic motor through a pipeline; when the working temperature of the hydraulic motor is higher than a set temperature threshold, the flow control valve is suitable for controlling the increase in the displacement of the secondary pump.

[0008] Preferably, the temperature threshold includes a normal operating threshold and a limit temperature threshold, and the limit temperature threshold is greater than the normal operating threshold; when the operating temperature of the hydraulic motor is lower than the normal operating threshold, the flow control valve is suitable for controlling the displacement of the auxiliary pump to decrease; when the operating temperature of the hydraulic motor is higher than the normal operating threshold but lower than the limit temperature threshold, the flow control valve is suitable for controlling the displacement of the auxiliary pump to increase; when the operating temperature of the hydraulic motor is higher than the limit temperature threshold, the control circuit is suitable for controlling the main pump to shut down.

[0009] Preferably, when the operating temperature of the hydraulic motor is lower than the normal operating threshold, the control circuit is suitable for controlling the displacement of the main pump to increase; when the operating temperature of the hydraulic motor is higher than the normal operating threshold but lower than the limit temperature threshold, the control circuit is suitable for controlling the displacement of the main pump to decrease.

[0010] Preferably, the flushing oil delivered to the hydraulic motor by the auxiliary pump flows back to the oil tank through the return branch; the monitoring module is installed in the return branch, and then the temperature of the return flushing oil is detected by the temperature sensor to determine the working temperature of the hydraulic motor.

[0011] Preferably, the monitoring module also includes a metal particle sensor, which is suitable for detecting the content of metal particles in the returning flushing oil; if the detected metal particle content is greater than a set threshold, the control loop is suitable for controlling the output flow of the main pump to be reduced to a minimum or 0.

[0012] Preferably, the monitoring module also includes a first flow detection device, and the cooling circuit also includes a second flow detection device; the first flow detection device is used to detect the first flow of the flushing oil return, and the second flow detection device is used to detect the second flow output by the auxiliary pump; if the difference between the first flow and the second flow is greater than a set threshold, it is judged that the hydraulic motor has a leak, and then the displacement of the main pump is reduced to 0 through the control circuit and shut down.

[0013] Preferably, the control circuit includes a regulating valve; the regulating valve is suitable for adjusting its own opening to control and regulate the displacement of the main pump.

[0014] Preferably, the main pump adopts a variable pump, and the control circuit also includes a variable piston cylinder. The output end of the variable piston cylinder is cooperatively connected to the main pump, and the regulating valve is connected between the output end of the main pump and the variable piston cylinder; the regulating valve is suitable for adjusting the stroke of the variable piston cylinder to control the displacement of the main pump.

[0015] Compared with the prior art, the beneficial effects of this application are:

[0016] By detecting the working status of the hydraulic motor and controlling the working status of the main pump according to the detection results, when the hydraulic motor is abnormal, the output speed of the hydraulic motor can be reduced in time or it can be shut down directly, thereby effectively ensuring the safe operation of the hydraulic motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the overall architecture of this application.

[0018] Figure 2 This is a schematic diagram of the overall hydraulic structure of this application.

[0019] In the figure: hydraulic motor 100, main pump 200, oil tank 300, monitoring module 400, first flow detection device 401, metal particle sensor 402, temperature sensor 403, control circuit 500, regulating valve 501, first variable piston cylinder 502, cooling circuit 600, auxiliary pump 601, flow control valve 602, second variable piston cylinder 603, third variable piston cylinder 604, second flow detection device 605. DETAILED DESCRIPTION

[0020] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0021] In the description of the present application, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of the present application.

[0022] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0023] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0025] The terms "including" and "having" and any variations thereof in the specification and claims of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0026] One of the preferred embodiments of the present application is as follows: Figure 1 As shown, a closed monitoring and control system for a hydraulic motor includes a hydraulic motor 100, a main pump 200, an oil tank 300, a control circuit 500 and a monitoring module 400. The oil tank 300 is used to hold oil, and the main pump 200 can pump the oil in the oil tank 300 to the hydraulic motor 100, and then the hydraulic motor 100 can convert hydraulic energy into mechanical energy for output. The purpose of this embodiment is to monitor the working state of the hydraulic motor 100; that is, the monitoring module 400 can detect the working state of the hydraulic motor 100, and the control circuit 500 can control the displacement of the main pump 200 according to the detection result of the monitoring module 400, and then control the output speed of the hydraulic motor 100.

[0027] Specifically, when the monitoring module 400 detects that the hydraulic motor 100 has an abnormal working state, the displacement of the main pump 200 can be reduced through the control circuit 500, and the output speed of the hydraulic motor 100 can be reduced synchronously. In extreme cases, the main pump 200 can be shut down, that is, the displacement is 0; at this time, the hydraulic motor 100 will also stop working, so that the abnormal situation of the hydraulic motor 100 can be effectively suppressed to ensure the safe operation of the hydraulic motor 100 and avoid the spread of faults.

[0028] It is understandable that the abnormal conditions that may occur when the hydraulic motor 100 is working include abnormal temperature, abnormal wear, and leakage. Among them, for the two abnormal conditions of abnormal wear and leakage, the hydraulic motor 100 needs to be shut down in time for maintenance; and for the abnormal temperature condition, it needs to be judged according to the specific situation. If the temperature is only slightly higher than the normal working temperature, then it is only necessary to increase the cooling of the hydraulic motor 100. If the temperature is too high, the hydraulic motor 100 needs to be shut down to avoid burning the hydraulic motor 100. For the convenience of understanding, the control process of the hydraulic motor 100 when facing different abnormal conditions will be described in detail below.

[0029] 1. Regarding the abnormal temperature state of the hydraulic motor 100.

[0030] In this embodiment, Figure 1 and Figure 2 As shown, the hydraulic motor closed monitoring and control system of the present application further includes a cooling circuit 600 , and the cooling circuit 600 can output flushing oil to the hydraulic motor 100 for temperature reduction and cooling according to the temperature detection result of the monitoring module 400 .

[0031] It is understandable that, during the operation of the hydraulic motor 100, an independent cooling circuit 600 may be provided to output flushing oil to the hydraulic motor 100, and the flushing oil absorbs the heat of the hydraulic motor 100 through heat transfer, and the heat of the hydraulic motor 100 is dissipated by the reflux of the flushing oil. When the hydraulic motor 100 is operating normally, or when the operating temperature of the hydraulic motor 100 is low, the cooling circuit 600 may be opened normally or remain closed; when the operating temperature of the hydraulic motor 100 exceeds a set threshold, the cooling circuit 600 may be opened or the output of the flushing oil may be increased, thereby accelerating the heat dissipation of the hydraulic motor 100.

[0032] It should be known that the flushing oil can be directly sprayed on the hydraulic motor 100 to achieve cooling, or the hydraulic motor 100 can be immersed in the flushing oil for cooling.

[0033] Specifically, Figure 2As shown, the monitoring module 400 includes a temperature sensor 403, and the cooling circuit 600 includes an auxiliary pump 601 and a flow control valve 602. The temperature sensor 403 can detect the working temperature of the hydraulic motor 100; the driving end of the auxiliary pump 601 is connected to the main pump 200 in a transmission manner, so that when the main pump 200 is working under the drive of the motor, the auxiliary pump 601 can rotate synchronously with the main pump 200. The input end of the auxiliary pump 601 is connected to the oil tank 300, and the output end of the auxiliary pump 601 extends to the position of the hydraulic motor 100 through a pipeline, so that when the auxiliary pump 601 is working, the oil in the oil tank 300 can be pumped to the position of the hydraulic motor 100 as a flushing oil. When the working temperature of the hydraulic motor 100 is higher than the set temperature threshold, the flow control valve 602 can control the displacement of the auxiliary pump 601 to increase, thereby increasing the amount of flushing oil for cooling the hydraulic motor 100 to improve the heat dissipation efficiency of the hydraulic motor 100.

[0034] It should be known that the specific structures and working principles of the temperature sensor 403, the auxiliary pump 601 and the flow control valve 602 are well-known technologies to those skilled in the art, so they will not be elaborated in detail here. There are many ways for the flow control valve 602 to control the displacement of the auxiliary pump 601, which are specifically related to the type of the auxiliary pump 601. For example, the flow control valve 602 can be installed at the output end of the auxiliary pump 601, and then the displacement of the auxiliary pump 601 can be controlled by the opening of the flow control valve 602. For example Figure 2 As shown, the auxiliary pump 601 is a variable pump, and the displacement of the auxiliary pump 601 is controlled by the second variable piston cylinder 603 and the third variable piston cylinder 604; wherein, the third variable piston cylinder 604 is an elastic cylinder, the second variable piston cylinder 603 is a hydraulic cylinder, the second variable piston cylinder 603 and the third variable piston cylinder 604 are respectively driven and connected to the two ends of the displacement control rod of the auxiliary pump 601; the flow control valve 602 is connected to the second variable piston cylinder 603, and then the flow control valve 602 supplies oil or returns oil to the rodless chamber of the second variable piston cylinder 603 through the hydraulic circuit to drive the displacement control rod of the auxiliary pump 601 to rotate to realize displacement control.

[0035] It is understandable that the temperature at which the hydraulic motor 100 can operate is within a limited range. If this limited range is exceeded, the hydraulic motor 100 may burn out, and the hydraulic motor 100 needs to be shut down. Then the temperature threshold can be set to include a normal operating threshold and an extreme temperature threshold, and the extreme temperature threshold is greater than the normal operating threshold. When the operating temperature of the hydraulic motor 100 is lower than the normal operating threshold, the flow control valve 602 can control the displacement of the auxiliary pump 601 to decrease. When the operating temperature of the hydraulic motor 100 is higher than the normal operating threshold but lower than the extreme temperature threshold, the flow control valve 602 can control the displacement of the auxiliary pump 601 to increase. When the operating temperature of the hydraulic motor 100 is higher than the extreme temperature threshold, the control circuit 500 can control the main pump 200 to shut down, and the hydraulic motor 100 will also shut down.

[0036] It should be noted that the auxiliary pump 601 and the main pump 200 are synchronously driven by a motor, so the output power W of the motor needs to meet the displacement requirements of the auxiliary pump 601 and the main pump 200 at the same time.

[0037] Those skilled in the art should know that when the hydraulic motor 100 is working, the working temperature of the hydraulic motor 100 is mainly generated by the output shaft transmission, that is, the faster the output speed of the hydraulic motor 100, the higher the working temperature of the hydraulic motor 100. Therefore, in this embodiment, when the working temperature of the hydraulic motor 100 is lower than the normal working threshold, the control circuit 500 can control the displacement of the main pump 200 to increase; when the working temperature of the hydraulic motor 100 is higher than the normal working threshold but lower than the limit temperature threshold, the control circuit 500 can control the displacement of the main pump 200 to decrease.

[0038] It is understandable that when the operating temperature of the hydraulic motor 100 is lower than the normal operating threshold, it means that the cooling efficiency of the hydraulic motor 100 by the cooling circuit 600 through the flushing oil is greater than the heat generation efficiency of the hydraulic motor 100 when the hydraulic motor 100 is working. At this time, the hydraulic motor 100 can appropriately increase its output speed, that is, the main pump 200 can appropriately increase the displacement until the heat generation efficiency of the hydraulic motor 100 and the cooling efficiency of the cooling circuit 600 are balanced. When the heat generation efficiency of the hydraulic motor 100 is greater than the cooling efficiency of the cooling circuit 500, the displacement of the auxiliary pump 601 in the cooling circuit 600 may be increased, thereby increasing the amount of flushing oil to improve the cooling efficiency; if the cooling circuit 600 has been operating at the maximum cooling efficiency, that is, when the auxiliary pump 601 reaches the maximum displacement, the cooling efficiency of the cooling circuit 600 still cannot meet the cooling of the hydraulic motor 100. At this time, the hydraulic motor 100 can reduce the output speed by reducing the displacement of the main pump 200, thereby reducing the cooling efficiency of the hydraulic motor 100 until the cooling efficiency of the cooling circuit 600 is greater than or equal to the heat generation efficiency of the hydraulic motor 100. Of course, when the operating temperature of the hydraulic motor 100 exceeds the normal operating threshold, the displacement of the auxiliary pump 601 can be increased while the displacement of the main pump 200 is reduced to further accelerate the above-mentioned heat dissipation balance process.

[0039] It should be known that there are many specific ways for the temperature sensor 403 to detect the working temperature of the hydraulic motor 100. The temperature sensor 403 can directly detect the temperature of the hydraulic motor 100. However, considering that the flushing oil needs to spray or soak the hydraulic motor 100, the installation of the temperature sensor 403 may be affected, thereby causing inaccurate detection results of the temperature sensor 403. Therefore, in this embodiment, the working temperature of the hydraulic motor 100 can be judged by the temperature of the flushing oil that returns after absorbing heat.

[0040] Specifically, Figure 2 As shown, the flushing oil delivered to the hydraulic motor 100 by the auxiliary pump 601 flows back to the oil tank 300 through the return branch. The monitoring module 400 is installed on the return branch, and then the temperature of the return flushing oil is detected by the temperature sensor 403 to determine the working temperature of the hydraulic motor 100.

[0041] It is understandable that the temperature of the flushing oil returning during normal operation of the hydraulic motor 100 can be stored as a normal operating threshold. Then, when the flushing oil temperature detected by the temperature sensor 403 exceeds the normal operating threshold, it means that the operating temperature of the hydraulic motor 100 is relatively high at this time, and it is necessary to increase the cooling efficiency of the cooling circuit 600 and / or reduce the output speed of the hydraulic motor 100.

[0042] 2. Abnormal wear of the hydraulic motor 100.

[0043] In this embodiment, Figure 2 As shown, the monitoring module 400 also includes a metal particle sensor 402, which is also arranged in the return branch, and can detect the content of metal particles in the return flushing oil. If the detected metal particle content is greater than the set threshold, the control circuit 500 can control the output flow of the main pump 200 to be reduced to the minimum or 0.

[0044] It is understandable that the wear position of the hydraulic motor 100 is generally at the output shaft position, that is, the output shaft of the hydraulic motor 100 may be bent or otherwise abnormal under the action of the load, which in turn causes the output shaft to jump during the rotation speed, thereby causing the wear of the hydraulic motor 100 to increase, and the increased wear will also increase the operating temperature of the hydraulic motor 100 and reduce the transmission efficiency. The output shaft is generally made of metal, and during the rotation of the output shaft, metal particles will be generated by grinding with the housing, and the metal particles will flow back along with the flushing oil, so the wear condition of the hydraulic motor 100 can be judged by detecting the metal particle content in the flushing oil flowing back.

[0045] It should be known that the specific structure and working principle of the metal particle sensor 402 are well-known technologies to those skilled in the art, so they will not be elaborated in detail here. In the entire hydraulic drive system, the output flow of the main pump 200 may not only be used to drive the hydraulic motor 100, but may also be used for other drives; therefore, when the wear of the hydraulic motor 100 is detected, the main pump 200 can reduce the output flow to the minimum to shut down the hydraulic motor 100. Of course, if the main pump 200 is only used to drive the hydraulic motor 100 to transmit, then when the wear of the hydraulic motor 100 is detected, the output flow of the main pump 200 can be directly controlled to be reduced to 0.

[0046] 3. Leakage of the hydraulic motor 100 occurs.

[0047] In this embodiment, Figure 2 As shown, the monitoring module 400 further includes a first flow detection device 401, and the cooling circuit 600 further includes a second flow detection device 605. The first flow detection device 401 is installed with the return branch to detect the first flow of the flushing oil return, and the second flow detection device 605 is installed at the output end of the auxiliary pump 601 to detect the second flow output by the auxiliary pump 601. If the difference between the first flow and the second flow is greater than the set threshold, it is determined that the hydraulic motor 100 has a leak, and then the displacement of the main pump 200 is reduced to 0 through the control circuit 500 and shut down.

[0048] It is understandable that the flow rate of the flushing oil delivered to the hydraulic motor 100 by the cooling reflux 600 through the auxiliary pump 601 is theoretically equal to the reflux rate of the flushing oil; considering the loss of the oil circuit, the difference between the flushing oil flow rate output by the auxiliary pump 601 and the reflux rate of the flushing oil after cooling can be regarded as a constant, which is the set threshold. If the hydraulic motor 100 leaks, the oil delivered to the hydraulic motor 100 by the main pump 200 will reflux along with the flushing oil, which will lead to an increase in the reflux rate of the flushing oil, that is, the difference between the flushing oil flow rate output by the auxiliary pump 601 and the reflux rate of the flushing oil after cooling exceeds the set threshold, and it can be determined that the hydraulic motor 100 has a leak. For leaks in the hydraulic motor 100, it is necessary to shut down the machine for maintenance.

[0049] In the embodiment of the present application, there are multiple specific structures of the control circuit 500 that can realize the displacement control of the main pump 200; for the sake of easy understanding, the following will be described in detail using one of the structures. Figure 2 As described above, the control circuit 500 includes a regulating valve 501 ; the regulating valve 501 can adjust its opening to control and adjust the displacement of the main pump 200 .

[0050] It is understandable that there are many specific implementation methods for the regulating valve 501 to adjust and control the displacement of the main pump 200 through its own opening. For example, the regulating valve 501 can throttle the output flow of the main pump 200; for another example, if the main pump 200 adopts a variable pump, the displacement control can be achieved by driving and controlling the variable control rod of the main pump 200. For the sake of easy understanding, the following will be described in detail by taking the main pump 200 adopting a variable pump as an example.

[0051] Specifically, Figure 2 As shown, the control circuit 500 also includes a variable piston cylinder, namely a first variable piston cylinder 502. The output end of the first variable piston cylinder 502 is drivingly connected to the variable control rod of the main pump 200, and the regulating valve 501 is connected between the output end of the main pump 200 and the first variable piston cylinder 502; the regulating valve 501 can adjust its own opening to control the amount of oil entering the first variable piston cylinder 502, and then realize the displacement control of the main pump 200 by controlling the stroke of the first variable piston cylinder 502.

[0052] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. A closed monitoring and control system for a hydraulic motor, characterized in that: It includes a hydraulic motor, a main pump, an oil tank, a control circuit and a monitoring module; the main pump is suitable for pumping the oil in the oil tank to the hydraulic motor, so that the hydraulic motor converts hydraulic energy into mechanical energy for output; the monitoring module is suitable for detecting the working state of the hydraulic motor, and the control circuit is suitable for controlling the displacement of the main pump according to the detection result of the monitoring module.

2. The hydraulic motor closed monitoring and control system according to claim 1, characterized in that: The hydraulic motor closed monitoring and control system also includes a cooling circuit, which is suitable for outputting flushing oil to the hydraulic motor for cooling according to the temperature detection result of the monitoring module.

3. The hydraulic motor closed monitoring and control system according to claim 2, characterized in that: The monitoring module includes a temperature sensor, and the cooling circuit includes a secondary pump and a flow control valve; The temperature sensor is suitable for detecting the working temperature of the hydraulic motor; the driving end of the auxiliary pump is connected to the main pump in a transmission manner, the input end of the auxiliary pump is connected to the oil tank, and the output end of the auxiliary pump extends to the position of the hydraulic motor through a pipeline; When the operating temperature of the hydraulic motor is higher than a set temperature threshold, the flow control valve is adapted to control the displacement of the auxiliary pump to increase.

4. The closed monitoring and control system for a hydraulic motor as claimed in claim 3, characterized in that: The temperature threshold comprises a normal operating threshold and a limit temperature threshold, and the limit temperature threshold is greater than the normal operating threshold; When the operating temperature of the hydraulic motor is lower than the normal operating threshold, the flow control valve is adapted to control the displacement of the auxiliary pump to decrease; When the operating temperature of the hydraulic motor is higher than the normal operating threshold but lower than the limit temperature threshold, the flow control valve is adapted to control the displacement of the auxiliary pump to increase; When the operating temperature of the hydraulic motor is higher than the limit temperature threshold, the control circuit is suitable for controlling the main pump to shut down.

5. The hydraulic motor closed monitoring and control system according to claim 4, characterized in that: When the operating temperature of the hydraulic motor is lower than the normal operating threshold, the control circuit is adapted to control the displacement of the main pump to increase; When the operating temperature of the hydraulic motor is higher than the normal operating threshold but lower than the limit temperature threshold, the control circuit is adapted to control the displacement of the main pump to decrease.

6. The hydraulic motor closed monitoring and control system according to claim 3, characterized in that: The flushing oil delivered by the auxiliary pump to the hydraulic motor flows back to the oil tank through the return branch; The monitoring module is installed in the return branch, and then detects the temperature of the return flushing oil through the temperature sensor to determine the working temperature of the hydraulic motor.

7. The hydraulic motor closed monitoring and control system according to claim 6, characterized in that: The monitoring module further comprises a metal particle sensor, which is adapted to detect the content of metal particles in the refluxed flushing oil; If the detected metal particle content is greater than a set threshold, the control circuit is suitable for controlling the output flow of the main pump to be reduced to a minimum or 0.

8. The hydraulic motor closed monitoring and control system according to claim 6, characterized in that: The monitoring module further includes a first flow detection device, and the cooling circuit further includes a second flow detection device; The first flow detection device is used to detect a first flow rate of the flushing oil return, and the second flow detection device is used to detect a second flow rate output by the auxiliary pump; If the difference between the first flow rate and the second flow rate is greater than a set threshold value, it is determined that the hydraulic motor has a leak, and then the displacement of the main pump is reduced to 0 through the control circuit and the main pump is shut down.

9. The hydraulic motor closed monitoring and control system according to any one of claims 1 to 8, characterized in that: The control loop includes a regulating valve; the regulating valve is suitable for adjusting its own opening to control and regulate the displacement of the main pump.

10. The hydraulic motor closed monitoring and control system according to claim 9, characterized in that: The main pump adopts a variable pump, and the control circuit also includes a variable piston cylinder. The output end of the variable piston cylinder is connected to the main pump, and the regulating valve is connected between the output end of the main pump and the variable piston cylinder; the regulating valve is suitable for adjusting the stroke of the variable piston cylinder to control the displacement of the main pump.

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