Plunger pump, hydraulic system and fault response control method of hydraulic system

Abstract

The invention relates to the technical field of plunger pumps, in particular to a plunger pump, a hydraulic system and a fault response control method of the hydraulic system. The plunger pump comprises a pump body, an outlet switch valve, a pressure feedback valve, an unloading valve, a signal receiving valve and a fault detector. The pump body includes a housing, a swash plate, a rotor, and a plunger. The shell is provided with a first oil outlet and an oil return opening. The outlet switch valve controls opening and closing of the first oil outlet. The pressure feedback valve adjusts the inclination angle of the swash plate according to the load. The signal receiving valve controls the first oil outlet or the oil return opening to be communicated with the hydraulic control oil opening and an inlet of the unloading valve. When the first oil outlet is communicated with the hydraulic control oil port and the unloading valve, the first oil outlet is closed, the unloading valve is opened, and the inclination angle of the swash plate is adjusted to be 0; and when the oil return port is communicated with the hydraulic control oil port and the unloading valve, the first oil outlet is opened, and the unloading valve is closed. The hydraulic system comprises a plunger pump. The fault response method is applied to the hydraulic system. Therefore, the problem of oil pollution diffusion caused by plunger pump faults is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of piston pumps, and more particularly, to a piston pump, a hydraulic system and a fault response control method thereof. Background Art

[0002] As the core power component of a hydraulic system, the main hydraulic pump's core function is to continuously output hydraulic energy that meets the system's required pressure and flow rate. When the main hydraulic pump suffers from wear failure, the contaminants generated by mechanical wear of the moving pairs inside the main hydraulic pump will enter the hydraulic system pipeline along with the output oil. When these contaminants flow through precision accessories such as hydraulic control valves, it may cause progressive damage such as surface scratches and seal failures of key components. More seriously, when the pollution particles accumulate at the hydraulic system filter, causing abnormal pressure difference in the return oil pipeline, it will trigger the abnormal opening of the system return oil safety valve, resulting in the reverse flow of the contaminated oil containing wear products back to the hydraulic oil tank, causing secondary pollution to the entire hydraulic energy system.

[0003] Traditional hydraulic system designs mostly use oil filtration devices for protection, but they fail to effectively block the pollution diffusion path caused by the wear failure of the main pump. Therefore, there is an urgent need to develop a new type of hydraulic system that can real-time monitor the wear state of the main pump, actively isolate the contaminated oil, and establish a multiple protection mechanism to block the conduction path of contaminants inside the hydraulic energy system and ensure that the cleanliness of the hydraulic oil in the hydraulic oil tank is maintained within the safe threshold range. Summary of the Invention

[0004] To solve the problem of oil pollution diffusion caused by piston pump failures, the present invention provides a piston pump, a hydraulic system and a fault response control method thereof.

[0005] In a first aspect, the present invention provides a piston pump, which includes: A pump main body, the pump main body includes a housing, a swash plate, a rotor and a piston; the swash plate, the rotor and the piston are all located in the housing; the swash plate is rotatably connected to the housing; the rotor is rotatably connected to the housing, and the piston is slidably connected to the rotor; one end of the piston abuts against the swash plate; the housing has a first oil outlet and an oil return port; An outlet switch valve, the outlet switch valve is detachably connected to the housing; the outlet switch valve controls the opening and closing of the first oil outlet; the outlet switch valve is a hydraulic control valve; the outlet switch valve has a hydraulic control oil port; A pressure feedback valve, the pressure feedback valve is detachably connected to the housing; the pressure feedback valve adjusts the tilt angle of the swash plate according to the load; A relief valve, the relief valve is detachably connected to the pressure feedback valve; the outlet of the relief valve is communicated with the pressure feedback valve; A signal receiving valve, which is detachably connected to the housing; the signal receiving valve controls the first oil outlet or the oil return port to communicate with the hydraulic control port and the inlet of the unloading valve; in a state where the first oil outlet communicates with the hydraulic control port, the outlet switch valve closes the first oil outlet; in a state where the oil return port communicates with the hydraulic control port, the outlet switch valve opens the first oil outlet; in a state where the first oil outlet communicates with the inlet of the unloading valve, the unloading valve opens, and the tilt angle of the swash plate is adjusted to 0; in a state where the oil return port communicates with the inlet of the unloading valve, the unloading valve closes. A fault detector, which is detachably connected to the housing; the fault detector detects fault data of the pump body; the fault detector is electrically connected to the signal receiving valve.

[0006] In some embodiments, the outlet switch valve includes a valve body, a valve core, and an elastic driving member; the valve core is located within the valve body; the valve core is slidably connected to the valve body; the valve body has a hydraulic control port, an oil inlet, and a second oil outlet; the valve core separates the hydraulic control port from the oil inlet and the second oil outlet respectively; the elastic driving member applies a driving force to the valve core to move towards the second oil outlet; the movement of the valve core controls the on-off of the oil inlet and the second oil outlet; the oil inlet communicates with the first oil outlet of the pump body.

[0007] In some embodiments, the signal receiving valve is a two-position three-way valve; the signal receiving valve has a first oil port, a second oil port, and a third oil port; the first oil port communicates with the first oil outlet; the second oil port communicates with the oil return port; the third oil port communicates with the inlet of the unloading valve and the hydraulic control port respectively; the signal receiving valve has a first working position and a second working position. In a state of the first working position, the first oil port communicates with the third oil port, and the second oil port is disconnected. In a state of the second working position, the second oil port communicates with the third oil port, and the first oil port is disconnected.

[0008] In some embodiments, the fault detector includes an oil pressure detector and an oil temperature detector.

[0009] In a second aspect, the present invention provides a hydraulic system, which includes the plunger pump according to any one of the first aspects, and further includes: A load device, and the plunger pump drives the load device to work.

[0010] In a third aspect, the present invention provides a hydraulic system fault response control method, which is applied to the hydraulic system described in the second aspect. The hydraulic system fault response control method includes: Step S10: Based on the plunger pump being in a working state, the fault level of the pump body detected by the fault detector is obtained in real time at a preset frequency; when the plunger pump is in the working state, the oil return port of the pump body is respectively communicated with the inlet of the unloading valve and the oil control port of the outlet switching valve; Step S20: Based on the fault level of the pump body exceeding a first threshold, control the signal receiving valve to communicate the first oil outlet of the pump body with the inlet of the unloading valve and the hydraulic oil control port of the outlet switching valve respectively.

[0011] In some embodiments, step S20 includes: Based on the fault level of the pump body exceeding the first threshold, control the signal receiving valve to communicate the first oil outlet of the pump body with the inlet of the unloading valve and the hydraulic oil control port of the outlet switching valve in sequence at a preset interval duration.

[0012] In some embodiments, step S20 includes: Step S21: Based on the fault level of the pump body being between the first threshold and the second threshold, control the signal receiving valve to communicate the first oil outlet of the pump body with the inlet of the unloading valve and the hydraulic oil control port of the outlet switching valve in sequence at an interval of a first preset duration; the second threshold is greater than the first threshold.

[0013] In some embodiments, step S20 includes: Step S22: Based on the fault level of the pump body being between the second threshold and the third threshold, control the signal receiving valve to communicate the first oil outlet of the pump body with the inlet of the unloading valve and the hydraulic oil control port of the outlet switching valve in sequence at an interval of a second preset duration; the third threshold is greater than the second threshold; the second preset duration is less than the first preset duration.

[0014] In some embodiments, the hydraulic system fault response control method further includes: Step S30: Based on the fault level of the pump body being between the first threshold and the base threshold, control at least some of the load devices to turn off; the first threshold is greater than the base threshold; Step S40: Based on at least some of the load devices pausing operation due to a fault, accumulate the duration during which the fault level is greater than the base threshold; Step S50: Based on the duration being greater than a preset duration, control the signal receiving valve to communicate the first oil outlet with the inlet of the unloading valve and the hydraulic oil control port of the outlet switching valve respectively; Step S60, based on the duration being less than the preset duration, restart the load device that was paused due to a fault.

[0015] To solve the problem of the spread of oil pollution caused by the failure of the plunger pump, the present invention has the following advantages: The real-time fault degree of the plunger pump is detected by a fault detector, and a signal is sent to the signal receiving valve. Thus, the opening and closing of the first oil outlet are controlled by controlling the outlet switch valve, and whether the angle of the swash plate is reset to zero is controlled by controlling the opening and closing of the unloading valve. When a fault occurs in the plunger pump, the angle of the swash plate is adjusted to 0 and the first oil outlet is closed, so that the plunger pump stops outputting oil, thereby preventing the plunger pump from discharging the contaminated oil into the downstream pipeline of the hydraulic system, and further avoiding the contamination of the load device downstream of the hydraulic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The structural schematic diagram of a plunger pump according to an embodiment is shown; Figure 2 The schematic diagram of the closed state of an outlet switch valve according to an embodiment is shown; Figure 3 The schematic diagram of the open state of an outlet switch valve according to an embodiment is shown; Figure 4 The functional structural schematic diagram of an outlet switch valve according to an embodiment is shown; Figure 5 The flow schematic diagram of a hydraulic system fault response control method according to an embodiment is shown.

[0017] Reference numerals: 10 pump body; 11 first oil outlet; 12 oil return port; 20 outlet switch valve; 21 valve body; 211 hydraulic control oil port; 212 oil inlet; 213 second oil outlet; 214 first conical surface; 22 valve core; 221 second conical surface; 23 elastic driving member; 30 pressure feedback valve; 40 unloading valve; 50 signal receiving valve; 51 first oil port; 52 second oil port; 53 third oil port. DETAILED DESCRIPTION

[0018] Now, the content of the present disclosure will be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those of ordinary skill in the art to better understand and thus implement the content of the present disclosure, rather than implying any limitation on the scope of the present disclosure.

[0019] As used herein, the term "comprising" and its variants are to be construed as open-ended terms meaning "including but not limited to". The term "based on" is to be construed as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be construed as "at least one embodiment". The term "another embodiment" is to be construed as "at least one other embodiment". The orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation, or be constructed and operated in a specific orientation. Also, in addition to being used to indicate orientation or positional relationship, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present application can be understood according to specific circumstances. In addition, the terms "installed", "set", "provided with", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances. In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, the meaning of "a plurality of" is two or more.

[0020] The main hydraulic pump, as the core power component of the hydraulic system, functions to continuously output hydraulic energy that meets the pressure and flow requirements of the system. When wear failures occur in the hydraulic pump, the pollutants generated will enter the hydraulic system along with the output oil, resulting in the contamination of the accessories in the system. The existing technical solutions generally use filtering equipment to reduce the spread of pollution. However, when the pollutants accumulate at the system filter and cause abnormal pressure difference in the return oil pipeline, it will cause the abnormal opening of the system return oil safety valve, resulting in the reflux of the contaminated oil back to the fuel tank, causing more serious pollution. Therefore, there is an urgent need to develop a new type of hydraulic system that can monitor the wear status of the main pump in real time and isolate the contaminated oil in a timely manner to block the conduction path of pollutants within the hydraulic energy system.

[0021] In this embodiment, a plunger pump is provided, as Figure 1As shown in the figure, the piston pump may include a pump body 10, an outlet switching valve 20, a pressure feedback valve 30, a relief valve 40, a signal receiving valve 50, and a fault detector. The pump body 10 may include a housing, a swash plate, a rotor, and a piston. The swash plate, the rotor, and the piston are all located in the housing. The swash plate is rotatably connected to the housing, the rotor is rotatably connected to the housing, the piston is slidably connected to the rotor, and one end of the piston abuts against the swash plate. The housing has a first oil outlet 11 and an oil return port 12. The first oil outlet 11 may communicate the piston pump with the hydraulic system, and the oil return port 12 may communicate the piston pump with the fuel tank.

[0022] The outlet switching valve 20 is detachably connected to the housing. The outlet switching valve 20 can control the opening and closing of the first oil outlet 11. By closing the outlet switching valve 20, it is possible to prevent the contaminated oil from continuing to enter the hydraulic system for circulation. The outlet switching valve 20 is a hydraulically controlled valve, and the outlet switching valve 20 has a hydraulic control oil port 211. By connecting the hydraulic control oil port 211 to different pipelines, the opening and closing of the outlet switching valve 20 can be controlled.

[0023] The pressure feedback valve 30 is detachably connected to the housing. The pressure feedback valve 30 can automatically adjust the tilt angle of the swash plate according to the magnitude of the load in the hydraulic system, thereby controlling the output power of the piston pump.

[0024] The relief valve 40 is detachably connected to the pressure feedback valve 30. The outlet of the relief valve 40 communicates with the pressure feedback valve 30.

[0025] The signal receiving valve is detachably connected to the housing. The signal receiving valve can control the first oil outlet 11 or the oil return port 12 to communicate with the hydraulic control oil port 211 and the inlet of the relief valve 40. In the state where the first oil outlet 11 communicates with the hydraulic control oil port 211, high-pressure oil enters the hydraulic control oil port 211, and the outlet switching valve 20 will close the first oil outlet 11 to prevent the oil from entering the hydraulic system, thereby preventing the downstream load devices of the hydraulic system from being contaminated. In the state where the oil return port 12 communicates with the hydraulic control oil port 211, low-pressure oil enters the hydraulic control oil port 211, and the outlet switching valve 20 will open the first oil outlet 11, and the oil can enter the hydraulic system to participate in the normal circulation. In the state where the first oil outlet 11 communicates with the inlet of the relief valve 40, the relief valve 40 opens, high-pressure oil enters the pressure feedback valve 30, the tilt angle of the swash plate is adjusted to 0, and the piston pump stops sucking and pressing oil, so that the contaminated oil stops entering the hydraulic system. In the state where the oil return port 12 communicates with the inlet of the relief valve 40, the relief valve 40 closes, and the pressure feedback valve 30 normally adjusts the swash plate angle according to the load.

[0026] The fault detector is detachably connected to the housing. The fault detector can detect the fault data of the pump body 10, such as whether the oil temperature and oil pressure are normal, etc. The fault detector is electrically connected to the signal receiving valve 50, and the signal receiving valve 50 adjusts the potential according to the signal output by the fault detector.

[0027] The signal receiving valve 50 controls the opening and closing of the first oil outlet 11 by controlling the outlet switch valve 20, and controls whether the angle of the swash plate returns to zero by controlling the opening and closing of the unloading valve 40. When the fault detector detects an abnormality in the piston pump, the swash plate angle is adjusted to 0, the first oil outlet 11 is closed, and the piston pump stops outputting oil, thereby preventing the contaminated oil in the piston pump from entering the downstream pipeline of the hydraulic system and avoiding contamination of the downstream load devices in the hydraulic system. Thus, it can prevent the accumulation of contamination particles at the hydraulic system filter from triggering the abnormal opening of the system return oil safety valve, and further avoid the situation where the contaminated oil containing wear products flows back reversely to the hydraulic oil tank.

[0028] In this embodiment, as Figure 2 shown, the outlet switch valve 20 includes a valve body 21, a valve core 22, and an elastic driving member 23. The valve core 22 is located inside the valve body 21, and the valve core 22 is slidably connected to the valve body 21. The valve body 21 has a hydraulic control oil port 211, an oil inlet 212, and a second oil outlet 213. The valve core 22 separates the hydraulic control oil port 211 from the oil inlet 212 and the second oil outlet 213 respectively. The elastic driving member 23 can drive the valve core 22 to move towards the first oil outlet 11; the movement of the valve core 22 controls the opening and closing of the oil inlet 212 and the second oil outlet 213, and the oil inlet 212 is communicated with the first oil outlet 11 of the pump body 10. Among them, as Figure 4 shown, the valve body 21 may further include a first conical surface 214, and the valve core 22 may include a second conical surface 221. The first conical surface 214 is located at the entrance of the second oil outlet 213 near one end of the valve core 22, and the second conical surface 221 is located at one end of the valve core 22 near the second oil outlet 213. The inclination angles of the first conical surface 214 and the second conical surface 221 are different. When the first oil outlet 11 and the oil inlet 212 are communicated, the first conical surface 214 and the second conical surface 221 are in contact, and the first conical surface 214 and the second conical surface 221 form an angle with an opening direction towards the oil inlet 212 in the cross-section passing through the axis of the valve core 22. The pressure of the high-pressure oil entering the oil inlet 212 through the first oil outlet 11 can act on the second conical surface 221, and the component force of the acting force along the axial direction of the valve core 22 can cause the valve core 22 to have a tendency to move away from the second oil outlet 213.

[0029] When the hydraulic control oil port 211 is communicated with the oil return port 12, low-pressure oil enters the hydraulic control oil port 211, and the oil inlet port 212 is communicated with the first oil outlet port 11. The high-pressure oil entering the oil inlet port 212 will act on the second conical surface 221 at one end of the valve core 22 close to the second oil outlet port 213. The thrust generated by the high-pressure oil is greater than the combined force of the low-pressure oil thrust and the elastic driving part. Therefore, the high-pressure oil drives the valve core 22 to move away from the second oil outlet port 213. At this time, the oil inlet port 212 and the second oil outlet port 213 are communicated, and the oil can enter the hydraulic system through the first oil outlet port 11, the oil inlet port 212, and the second oil outlet port 213, realizing the normal operation of the piston pump. When the first oil outlet port 11 is communicated with the hydraulic control oil port 211, high-pressure oil enters the hydraulic control oil port 211. At this time, the oil pressures at both ends of the valve core 22 are equal and in opposite directions. Therefore, the valve core 22 moves towards the second oil outlet port 213 under the driving force of the elastic driving part 23 until the second oil outlet port 213 is blocked from the oil inlet port 212, that is, the closing of the first oil outlet port 11 is realized. As Figure 3 shown, at this time, the valve core 22 blocks the passage between the oil inlet port 212 and the second oil outlet port 213, and the contaminated oil cannot flow into the hydraulic system along the path of the first oil outlet port 11, the oil inlet port 212, and the second oil outlet port 213.

[0030] In this embodiment, as Figure 1 shown, the signal receiving valve 50 can be a two-position three-way valve. The signal receiving valve 50 can control the on-off of the unloading valve 40 and the outlet switching valve 20 through the change between two working positions. The signal receiving valve 50 has a first oil port 51, a second oil port 52, and a third oil port 53. The first oil port 51 is communicated with the first oil outlet port 11; the second oil port 52 is communicated with the oil return port 12; the third oil port 53 is respectively communicated with the inlet of the unloading valve 40 and the hydraulic control oil port 211. The signal receiving valve 50 has a first working position and a second working position.

[0031] In the state of the first working position, the first oil port 51 is communicated with the third oil port 53, and the second oil port 52 is disconnected. Therefore, the inlet of the unloading valve 40 and the hydraulic control oil port 211 are both communicated with the first oil outlet port 11. The high-pressure oil enters the pressure feedback valve 30 through the unloading valve 40, the swash plate tilt angle is adjusted to 0, and the piston pump stops sucking and pressing oil. The high-pressure oil enters the hydraulic control oil port 211. At this time, the oil pressures at both ends of the valve core 22 are equal and in opposite directions. Therefore, the valve core 22 moves towards the second oil outlet port 213 under the driving force of the elastic driving part 23 until the second oil outlet port 213 is blocked from the oil inlet port 212, and the oil cannot flow into the hydraulic system along the second oil outlet port 213. When a fault occurs in the piston pump, adjusting the signal receiving valve 50 to the first working position can isolate the contaminated oil in the hydraulic pump as early as possible and prevent the contamination from spreading along the hydraulic system.

[0032] In the state of the second working position, the second oil port 52 communicates with the third oil port 53, and the first oil port 51 is disconnected. Thus, both the inlet of the unloading valve 40 and the hydraulic control oil port 211 communicate with the oil return port 12. The unloading valve 40 is closed, and the pressure feedback valve 30 works normally. The hydraulic control oil port 211 communicates with the low-pressure oil. The spool 22 moves away from the second oil outlet 213 under the action of the high-pressure oil at the oil inlet 212. The oil can flow into the hydraulic system successively through the first oil outlet 11, the oil inlet 212, and the second oil outlet 213, and the hydraulic system maintains a normal working state.

[0033] In this embodiment, the fault detector may include an oil pressure detector and an oil temperature detector. After a fault occurs in the piston pump, both the oil pressure and the oil temperature will change. The fault detector can detect the change values of the oil pressure and the oil temperature within a certain time range. If the change values exceed a certain threshold, it can be considered that a fault has occurred in the piston pump. The fault detector will transmit a signal to the signal receiving valve, and then control the on-off of the unloading valve 40 and the outlet switch valve 20 to stop the hydraulic system from working to avoid the spread of contamination.

[0034] In this embodiment, a hydraulic system is provided. The hydraulic system includes the piston pump in any of the above embodiments, and also includes a load device. The piston pump can drive the load device to work. At the same time, the swash plate in the piston pump will adjust the tilt angle according to the load device to control the output power of the piston pump, so that the load device can obtain the required driving force and work normally.

[0035] Before the piston pump starts and when the engine starts, it is possible to control the piston pump to be in a state of zero pressure and zero flow output, that is, the output power is 0, thereby reducing the starting input power required by the engine. After the piston pump starts, in this embodiment, a hydraulic system fault response control method is provided. The hydraulic system fault response control method is applied to the hydraulic system in the above embodiment, as Figure 4 shown. The fault response control method of the hydraulic system includes step S10 to step S20, and the details of each step are as follows: Step S10, based on the piston pump being in a working state, obtain the fault level of the pump body 10 detected by the fault detector in real time at a preset frequency. Among them, the fault detector can judge whether a fault has occurred in the piston pump and the fault level by detecting the oil pressure and the oil temperature. When the piston pump is in a working state, the oil return port 12 of the pump body 10 communicates with the inlet of the unloading valve 40 and the control oil port of the outlet switch valve 20 respectively. The unloading valve 40 is closed, and the pressure feedback valve 30 works normally. The hydraulic control oil port 211 communicates with the low-pressure oil. The spool 22 moves away from the second oil outlet 213 under the action of the high-pressure oil at the oil inlet 212. The oil can flow into the hydraulic system successively through the first oil outlet 11, the oil inlet 212, and the second oil outlet 213, and the hydraulic system maintains a normal working state.

[0036] Step S20: Based on the failure level of the pump body 10 exceeding the first threshold, the control signal receiving valve 50 connects the first oil outlet 11 of the pump body 10 to the inlet of the unloading valve 40 and the hydraulic control oil port 211 of the outlet switch valve 20 respectively. The high-pressure oil enters the pressure feedback valve 30 through the unloading valve 40, the swash plate tilt angle is adjusted to 0, and the plunger pump stops sucking and pumping oil. The high-pressure oil enters the hydraulic control oil port 211. At this time, the oil pressures at both ends of the valve core 22 are equal and in opposite directions. Therefore, the valve core 22 moves towards the second oil outlet 213 under the driving force of the elastic driving member 23 until the second oil outlet 213 is blocked from the oil inlet 212, and the oil cannot flow into the hydraulic system along the second oil outlet 213, thereby preventing pollution from spreading along the hydraulic system.

[0037] In this embodiment, step S20 may include: Based on the failure level of the pump body 10 exceeding the first threshold, the control signal receiving valve 50 connects the first oil outlet 11 of the pump body 10 to the inlet of the unloading valve 40 and the hydraulic control oil port 211 of the outlet switch valve 20 at preset intervals in sequence, so that the high-pressure oil first enters the pressure feedback valve 30, the swash plate angle is adjusted to 0, and the outlet pressure of the plunger pump is adjusted to low pressure. Then, the outlet switch valve 20 is closed, the valve core 22 cuts off the passage between the oil inlet 212 and the second oil outlet 213, and the oil outlet of the plunger pump is closed. Adjusting the swash plate angle first and then closing the outlet of the plunger pump can prevent the plunger pump from being damaged due to excessive pressure inside the plunger pump.

[0038] In this embodiment, step S20 may include step S21, which is described in detail as follows: Step S21: Based on the failure level of the pump body 10 being between the first threshold and the second threshold, the control signal receiving valve 50 connects the first oil outlet 11 of the pump body 10 to the inlet of the unloading valve 40 and the hydraulic control oil port 211 of the outlet switch valve 20 at intervals of the first preset duration in sequence. Wherein, the second threshold is greater than the first threshold. When the failure level of the pump body 10 is relatively low, the interval time between adjusting the swash plate angle to 0 and closing the outlet of the pump body 10 can be controlled to be longer, so as to avoid excessive pressure inside the pump body 10 when the outlet of the pump body 10 is closed while the plunger in the pump body 10 is still operating.

[0039] In this embodiment, step S20 further includes step S22, which is described in detail as follows: Step S22: Based on the fault level of the pump body 10 being between the second threshold and the third threshold, the control signal receiving valve 50 connects the first oil outlet 11 of the pump body 10 to the inlet of the unloading valve 40 and the hydraulic control oil port 211 of the outlet switch valve 20 at intervals of a second preset duration. Here, the third threshold is greater than the second threshold, and the second preset duration is less than the first preset duration. That is, when the fault level of the pump body 10 is relatively high, the interval time between adjusting the swash plate angle to zero and closing the outlet of the pump body 10 can be controlled to be short. On the one hand, it can quickly stop the oil suction and oil discharge actions of the piston pump, and on the other hand, it can also prevent the contaminated oil from polluting the downstream load devices along the hydraulic system circuit.

[0040] In some other embodiments, when the fault level of the pump body 10 is too high, the input shaft can also be controlled to be disconnected from the main shaft of the piston pump, so as to stop the piston pump from working and prevent the oil return filter of the piston pump itself from being blocked. The oil return filter of the piston pump itself and the oil return filter of the hydraulic system are two different filters.

[0041] In this embodiment, the fault response control method of the hydraulic system further includes steps S30 to S60, which are specifically described as follows: Step S30: Based on the fault level of the pump body 10 being between the first threshold and the base threshold, control at least some of the load devices to close. Here, the first threshold is greater than the base threshold.

[0042] In the state where the fault level is less than the base threshold, the pump body 10 is in a normal working state. When the fault level is between the first threshold and the base threshold, it may not be a wear fault of the pump body 10, but a fault in the hydraulic system that can be automatically reset and eliminated. For example, when the set oil pressure of the overflow valve is inappropriate and the oil pressure is high, resulting in an increase in temperature, the hydraulic system can automatically control and adjust the set oil pressure of the overflow valve to quickly stabilize the oil temperature.

[0043] Therefore, for minor faults that can be quickly reset, the swash plate angle does not need to be adjusted to zero, and the outlet of the pump body 10 does not need to be closed. Instead, some of the load devices are closed. Based on the principle of constant pressure variable adjustment, the swash plate angle also automatically changes with the decrease in the load, reducing the output power of the piston pump.

[0044] Step S40: Based on at least one load device pausing operation due to a fault, accumulate the duration during which the cumulative fault level is greater than the base threshold.

[0045] Step S50: Based on the duration being greater than the preset duration, the control signal receiving valve 50 connects the first oil outlet 11 to the inlet of the unloading valve 40 and the hydraulic control oil port 211 of the outlet switch valve 20 respectively, so as to adjust the swash plate inclination to zero, close the first oil outlet 11 and perform manual maintenance. Here, the preset duration can be three minutes.

[0046] Step S60, based on the duration being less than the preset duration, restart the load device that was paused due to a fault.

[0047] Among them, shutting down some of the load devices can play a buffering role. On the one hand, it prepares for the actions of adjusting the swash plate angle to 0 and closing the first oil outlet 11 caused by wear faults, and at the same time ensures the continuous operation of the hydraulic system to avoid frequent accidental shutdowns.

[0048] Those of ordinary skill in the art can understand that the above embodiments are specific cases for implementing the present disclosure, and in actual applications, various changes can be made to them in form and details without departing from the scope of the present disclosure.

Claims

1. A plunger pump, characterized in that: The plunger pump comprises: A pump body, the pump body comprising a housing, a swash plate, a rotor and a plunger; the swash plate, the rotor and the plunger are all located in the housing; the swash plate is rotatably connected to the housing; the rotor is rotatably connected to the housing, and the plunger is slidably connected to the rotor; one end of the plunger abuts against the swash plate; the housing is provided with a first oil outlet and an oil return port; An outlet switch valve, the outlet switch valve is detachably connected to the housing; the outlet switch valve controls the opening and closing of the first oil outlet; the outlet switch valve is a hydraulically controlled valve; the outlet switch valve has a hydraulically controlled oil port; A pressure feedback valve, the pressure feedback valve is detachably connected to the housing; the pressure feedback valve adjusts the inclination angle of the swash plate according to the size of the load; An unloading valve, wherein the unloading valve is detachably connected to the pressure feedback valve; an outlet of the unloading valve is communicated with the pressure feedback valve; A signal receiving valve, wherein the signal receiving valve is detachably connected to the housing; the signal receiving valve controls the first oil outlet or the oil return port to be connected to the hydraulic oil port and the inlet of the unloading valve; when the first oil outlet is connected to the hydraulic oil port, the outlet switch valve closes the first oil outlet; when the oil return port is connected to the hydraulic oil port, the outlet switch valve opens the first oil outlet; when the first oil outlet is connected to the inlet of the unloading valve, the unloading valve is opened, and the inclination angle of the swash plate is adjusted to 0; when the oil return port is connected to the inlet of the unloading valve, the unloading valve is closed; A fault detector is detachably connected to the housing; the fault detector detects fault data of the pump body; and the fault detector is electrically connected to the signal receiving valve.

2. A plunger pump according to claim 1, characterized in that: The outlet switching valve includes a valve body, a valve core and an elastic driving member; the valve core is located within the valve body; the valve core is slidably connected to the valve body; the valve body has a hydraulic oil port, an oil inlet and a second oil outlet; the valve core separates the hydraulic oil port from the oil inlet and the second oil outlet respectively; the elastic driving member applies a driving force to the valve core to move toward the second oil outlet; the movement of the valve core controls the connection and disconnection of the oil inlet and the second oil outlet; the oil inlet is connected to the first oil outlet of the pump body.

3. A plunger pump according to claim 1, characterized in that: The signal receiving valve is a two-position three-way valve; the signal receiving valve has a first oil port, a second oil port and a third oil port; the first oil port is connected to the first oil outlet; the second oil port is connected to the oil return port; the third oil port is respectively connected to the inlet of the unloading valve and the hydraulic control oil port; the signal receiving valve has a first working position and a second working position; In the state of the first working position, the first oil port is connected with the third oil port, and the second oil port is disconnected; In the state of the second working position, the second oil port is communicated with the third oil port, and the first oil port is disconnected.

4. A plunger pump according to claim 1, characterized in that: The fault detector includes an oil pressure detector and an oil temperature detector.

5. A hydraulic system, characterized in that: The hydraulic system comprises: The plunger pump according to any one of claims 1 to 4; A load device, wherein the plunger pump drives the load device to operate.

6. A fault response control method for a hydraulic system, applied to the hydraulic system according to claim 5; characterized in that: The fault response control method of the hydraulic system comprises: Step S10, based on the plunger pump being in a working state, obtaining the fault level of the pump body detected by the fault detector in real time at a preset frequency; the plunger pump is in the working state, and the oil return port of the pump body is respectively connected to the inlet of the unloading valve and the oil control port of the outlet switch valve; Step S20, based on the fault level of the pump body exceeding the first threshold, controlling the signal receiving valve to connect the first oil outlet of the pump body with the inlet of the unloading valve and the hydraulic control oil port of the outlet switch valve respectively.

7. A fault response control method for a hydraulic system according to claim 6, characterized in that: The step S20 includes: based on the fault level of the pump body exceeding the first threshold, controlling the signal receiving valve to connect the first oil outlet of the pump body with the inlet of the unloading valve and the hydraulic control oil port of the outlet switch valve in sequence at preset intervals.

8. A fault response control method for a hydraulic system according to claim 7, characterized in that: The step S20 comprises: Step S21, based on the fault level of the pump body being between the first threshold and the second threshold, controls the signal receiving valve to connect the first oil outlet of the pump body with the inlet of the unloading valve and the hydraulic control oil port of the outlet switch valve in sequence at intervals of a first preset time length; the second threshold is greater than the first threshold.

9. A fault response control method for a hydraulic system according to claim 8, characterized in that: The step S20 comprises: Step S22, based on the fault level of the pump body being between the second threshold and the third threshold, controls the signal receiving valve to connect the first oil outlet of the pump body with the inlet of the unloading valve and the hydraulic control oil port of the outlet switch valve in sequence at intervals of a second preset time; the third threshold is greater than the second threshold; the second preset time is less than the first preset time.

10. A fault response control method for a hydraulic system according to claim 6, characterized in that: The fault response control method of the hydraulic system further includes: Step S30, based on the fault level of the pump body being between the first threshold and a basic threshold, controlling at least part of the load devices to be turned off; the first threshold is greater than the basic threshold; Step S40, based on at least part of the load devices suspending operation due to a fault, accumulating a duration during which the fault level is greater than the basic threshold; Step S50, based on the duration being greater than a preset duration, controlling the signal receiving valve to connect the first oil outlet to the inlet of the unloading valve and the hydraulic control oil port of the outlet switch valve respectively; Step S60: restarting the load device that has been suspended due to a fault based on the duration being less than the preset duration.

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