Motor pump set capable of recovering energy

Abstract

The invention relates to the technical field of hydraulic transmission and control, in particular to a motor pump set capable of recovering energy, which comprises a motor and a plunger pump, the motor and the plunger pump are connected through a valve body and transmit driving liquid, and a motor rotating shaft drives a cylinder body of the plunger pump to synchronously rotate; the valve body is provided with a low-pressure oil suction port and conveys driving liquid to the plunger pump in a one-way mode through the first low-pressure flow distribution port, and the plunger pump conveys the driving liquid to the high-pressure oil port in a one-way mode through the first high-pressure flow distribution port. A low-pressure oil return opening is further formed in the valve body and communicated with the low-pressure oil suction opening. The motor is matched with the plunger pump, the plunger pump can be used for conveying driving liquid to achieve the performance of the pump, gravitational potential energy of external equipment is converted into hydraulic pressure of the driving liquid, the plunger pump is driven to rotate reversely, so that the motor generates electricity, the working performance of the motor is achieved, energy recycling treatment is achieved, and the energy utilization rate can be effectively increased; and the energy waste is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic transmission and control, and in particular to a motor pump group capable of recovering energy. Background Art

[0002] With the rapid development of electrification, the demand for electrified engineering machinery, logistics equipment, etc. is growing rapidly. Due to the limitations of battery capacity and cost, and equipment space, it is impossible to increase the capacitance indefinitely. Therefore, the power system that can recover energy will become an important demand and highlight of future electrified equipment, especially for self-weighted return machinery such as three-way stacking forklifts and elevators. It is particularly suitable to use a hydraulic system that can recover energy. When the load of the traditional self-weight return hydraulic system drops or falls, the gravitational potential energy of the load is completely converted into heat energy, causing the hydraulic system to heat up seriously. The continuous increase in the oil temperature of the hydraulic system will cause the hydraulic system to fail to work normally. At this time, forced cooling is required, which not only causes multiple wastes of energy, but also because the hydraulic system has no energy recovery device, resulting in a large installed power of the hydraulic system itself. The installed power will directly affect the system energy consumption, and the direct consequence is that the equipment operation energy consumption and cost are both high.

[0003] The energy recovery hydraulic system can convert the gravity potential energy of the cargo driven down by the lifting cylinder into the gravity potential energy of the counterweight driven up by the counterweight accumulator, and cooperate with the reverse application of the motor - power generation function, so as to realize energy utilization. The hydraulic system has a simple structure, which can reduce the loss of oil during the circulation process and improve the energy recovery rate. This self-weight return hydraulic system with energy recovery can even be used for a long time without charging, and the battery capacity is also very low, so it has significant cost advantages. At present, most of the hydraulic systems with energy recovery mainly use a combination of motor and gear pump. Due to the defects of low pressure, low efficiency and high noise of gear pump, its wider application is limited.

[0004] Therefore, it is necessary to propose a more reasonable technical solution to solve the defects in the prior art. Summary of the invention

[0005] In order to at least overcome one of the defects mentioned above, the present invention proposes a motor pump group that can recover energy. By controlling the hydraulic channel at the pump group, the motor pump group can be operated under pump conditions or motor conditions, thereby realizing the motor driving the pump to operate or the pump driving the motor to generate electricity, thereby realizing energy recovery.

[0006] In order to achieve the above technical effects, the motor pump unit disclosed in the present invention can adopt the following technical solutions:

[0007] A motor pump group with energy recovery includes a motor and a plunger pump, the motor and the plunger pump are connected through a valve body and the valve body transmits driving fluid, the motor shaft passes through the valve body and is connected to drive the cylinder of the plunger pump to rotate synchronously; the valve body is provided with a low-pressure oil suction port and the low-pressure oil suction port unidirectionally transmits driving fluid to the cylinder of the plunger pump through a first low-pressure distribution port, the valve body is provided with a high-pressure oil port and the plunger pump unidirectionally transmits driving fluid to the high-pressure oil port through the first high-pressure distribution port; the valve body is also provided with a low-pressure oil return port and is connected with the low-pressure oil suction port, and the connection point is controlled by the valve body; the first low-pressure distribution port or the second low-pressure distribution port is connected with the plunger pump and cooperates with the plunger pump to enter the pump working condition or the motor working condition respectively.

[0008] The motor pump group disclosed above utilizes the cooperation of the motor and the plunger pump to realize pump working condition and motor working condition. Under the pump working condition, the motor drives the plunger pump to realize the pumping of the driving liquid; under the motor working condition, the reflux force of the driving liquid can be used to drive the motor to rotate to generate electricity, and the liquid pressure generated by the potential energy of the external equipment acting on the driving liquid is converted into electrical energy for storage, thereby realizing energy recovery and utilization, and improving the energy utilization rate.

[0009] Furthermore, the structure for limiting the flow of the driving fluid at the low-pressure oil suction port can adopt a variety of schemes, which are not limited to the only one. Here, optimization is made and one feasible option is proposed: the low-pressure oil suction port is equipped with a first one-way valve to limit the one-way entry of the driving fluid into the low-pressure oil suction port. When the pump is in operation, the first one-way valve is opened, and when the motor is in operation, the first one-way valve is closed. When such a scheme is adopted, the first one-way valve can be directly and detachably arranged in conjunction with the low-pressure oil suction port, or it can form an integral structure with the low-pressure oil suction port; when the first one-way valve is opened, the driving fluid can pass normally.

[0010] Furthermore, the structure for limiting the flow of the driving fluid at the low-pressure oil return port can also adopt a variety of schemes, which are not limited to the only one. Here, optimization is made and one feasible option is proposed: the low-pressure oil return port is provided with a second one-way valve, and the second one-way valve is used to limit the driving fluid from the first low-pressure distribution port to the low-pressure oil return port and discharge the valve body. When the pump is in operation, the second one-way valve is closed, and when the motor is in operation, the second one-way valve is opened. When such a scheme is adopted, the first one-way valve is closed while the second one-way valve is opened, so the refluxed driving fluid can only flow from the second one-way valve to the low-pressure return port.

[0011] Furthermore, when the driving fluid delivered outward by the plunger pump is insufficient, the output driving fluid can be increased by replenishing the fluid, which can be achieved through a variety of solutions, which are not limited to the only one. Here, an optimization is made and one of the feasible options is proposed: the valve body is provided with an oil replenishment channel, which extends from the low-pressure oil suction port and connects to the high-pressure oil port. The oil replenishment channel is provided with a third one-way valve and the third one-way valve is used to limit the driving fluid from the low-pressure oil suction port to the high-pressure oil port. When the oil needs to be replenished, the third one-way valve is opened, and when the motor is in operation, the third one-way valve is closed. When such a solution is adopted, the third one-way valve can control the opening and closing of the replenishment channel, and the driving fluid can only flow from the low-pressure oil suction port to the high-pressure oil port, thereby achieving replenishment.

[0012] Furthermore, when the delivery pressure of the driving liquid is relatively high, it causes a high pressure condition in the valve body, and pressure relief is required to maintain the pressure balance of the driving liquid. The specific pressure relief structure can adopt a variety of schemes, which are not limited to the only one. Here, we optimize and propose one of the feasible options: the valve body is also provided with an overflow structure, and the overflow structure is connected to the high-pressure oil port and the low-pressure oil return port respectively. The overflow structure limits the overflow of the driving liquid from the high-pressure oil port and the low-pressure oil return port to the outside through the overflow valve. When such a scheme is adopted, the overflow valve is closed under normal conditions, and the overflow treatment of the high-pressure oil port and the low-pressure oil return port can be realized respectively.

[0013] Furthermore, when the plunger pump is sucking and discharging oil, its action characteristics can be used to improve the efficiency of oil suction. Here, an optimization is made and one of the feasible options is proposed: a second low-pressure distribution port is also provided on the valve body, and the second low-pressure distribution port extends from the low-pressure oil suction port to connect to the plunger pump and transport the driving liquid into the plunger pump. When such a solution is adopted, the second low-pressure distribution port can fill the plunger pump with driving liquid, which can be used for the plunger to suck and transport oil on the one hand, and can be used to cool the plunger pump on the other hand to prevent the plunger pump from overheating.

[0014] Furthermore, the structure of the plunger pump can adopt a variety of forms. In order to improve the absorption and delivery of oil by the plunger pump, optimization is performed here and one of the feasible options is proposed: the plunger pump includes a plunger structure, the plunger structure includes a cylinder body and a plunger matched with the cylinder body, the cylinder body is provided with a first oil inlet and communicated with the first low-pressure distribution port, and the plunger is provided with a second oil inlet and communicated with the plunger pump housing cavity. When such a scheme is adopted, an oil inlet channel is formed in the plunger, and the driving liquid entering from the second oil inlet can pass through the oil inlet and enter the plunger cavity. When the plunger pump rotates and presses the plunger into the plunger cavity, the driving liquid in the plunger cavity is pressed out and enters the high-pressure oil port.

[0015] Furthermore, the valve body is used to connect the motor and the plunger pump, and the structure can be constructed in various forms, which is not limited to the only one. Here, an optimization is made and one of the feasible options is proposed: the middle part of the valve body is provided with an axial hole, and a bearing matching the motor shaft is provided in the axial hole; a lubrication channel is provided at the low-pressure oil inlet and extends to the axial hole, and the driving fluid enters the axial hole through the low-pressure oil inlet and is used to lubricate the bearing. When such a solution is adopted, the number of bearings in the axial hole is several, and includes bearings for radial support and axial abutment.

[0016] Furthermore, the structure in the plunger pump can be optimized to improve the efficiency of pumping the driving fluid. Here, the optimization is performed and one feasible option is proposed: the plunger pump also includes a slanted plate structure, the slanted plate is provided with a sliding plate that matches the plunger, the sliding plate is provided with a plunger ball socket and the end of the plunger is matched in the plunger ball socket, and the bottom of the plunger ball socket is provided with an oil hole that is connected and matched with the second oil inlet. When such a solution is adopted, the end of the plunger is a spherical structure and fits the plunger ball socket.

[0017] Furthermore, in order to better realize the oil absorption of the second oil inlet on the plunger, the structure of the sliding plate is optimized, and one feasible option is proposed here: a sliding plate oil chamber is provided on the end surface of the sliding plate away from the plunger ball socket, and the sliding plate oil chamber is connected to the plunger ball socket through an oil hole, and the area ratio of the oil hole to the sliding plate oil chamber is 0.4 to 0.9. When such a solution is adopted, the sliding plate oil chambers are evenly spaced along the circumference.

[0018] Compared with the prior art, some beneficial effects of the technical solution disclosed in the present invention include:

[0019] The motor in the present invention cooperates with the plunger pump to run more smoothly. The plunger pump can be used to deliver the driving liquid to achieve the performance of the pump. The gravitational potential energy of the external device can also be converted into the liquid pressure of the driving liquid, driving the plunger pump to run in the opposite direction so that the motor can generate electricity, thereby achieving the working performance of the motor. In this way, energy recovery processing is achieved, which can effectively improve the utilization rate of energy and avoid energy waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only represent some embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a schematic diagram of the structure of the motor pump group in the present invention.

[0022] Figure 2 for Figure 1 Schematic diagram of the structure of the middle valve body and plunger pump.

[0023] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure of section AA.

[0024] Figure 4 It is a schematic diagram of the overall structure of the valve body.

[0025] Figure 5 It is a schematic diagram of the front view structure of the valve body.

[0026] Figure 6 It is a schematic diagram of the side structure of the valve body.

[0027] Figure 7 for Figure 6 Schematic diagram of the cross-sectional structure of the BB section.

[0028] Figure 8 It is a schematic diagram of the hydraulic structure of the motor pump group in the present invention.

[0029] Fig. 9 It is a schematic diagram of the front view structure of the sliding plate.

[0030] Fig.10 It is a schematic diagram of the cross-sectional structure of the sliding disc.

[0031] In the above drawings, the meanings of the various reference numerals are as follows:

[0032] 1. Motor; 2. Spindle; 3. Valve body; 4. Piston pump; 21. Thrust bearing; 22. Needle bearing; 30a. Low-pressure oil suction port; 30b. High-pressure oil port; 30c. Low-pressure oil return port; 31. Shaft seal; 32. Bearing support; 33. First low-pressure distribution port; 34. High-pressure distribution port; 35. Overflow valve; 36. Second low-pressure distribution port; 37a. First check valve; 37b. Second check valve; 37c. Third check valve; 41. Distribution plate; 4 2. Cylinder body; 43. Plunger; 44. Sliding plate; 45. Swash plate positioning seat; 46. Swash plate; 47. Housing; 381. First oil hole; 382. Second oil hole; 383. Third oil hole; 384. Fourth oil hole; 385. Fifth oil hole; 386. Sixth oil hole; 387. Seventh oil hole; 441. Sliding plate oil chamber; 442. Plunger ball socket; 443. Oil hole; 444. Plunger center hole; 451. Oil groove; 452. Drainage hole. DETAILED DESCRIPTION

[0033] The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments.

[0034] In view of the low energy recovery rate of the hydraulic system in the prior art and the fact that the energy recovery process is subject to many restrictions, the following embodiment is optimized and a feasible option is proposed.

[0035] Example

[0036] The present embodiment provides a motor 1 pump group that can recover energy; it includes a motor 1 and a plunger pump 4; the motor 1 and the plunger pump 4 are connected through a valve body 3 and the valve body 3 transmits the driving liquid; the motor 1 shaft passes through the valve body 3 and is connected to drive the cylinder 42 of the plunger pump 4 to rotate synchronously; the valve body 3 is provided with a low-pressure oil suction port 30a, and the low-pressure oil suction port 30a unidirectionally transmits the driving liquid to the cylinder 42 of the plunger pump 4 through the first low-pressure distribution port 33; the valve body 3 is provided with a high-pressure oil port 30b, and the plunger pump 4 unidirectionally transmits the driving liquid to the high-pressure oil port 30b through the first high-pressure distribution port 34; the valve body 3 is also provided with a low-pressure oil return port 30c and is connected to the low-pressure oil suction port 30a; the connection is controlled by the valve body 3; the first low-pressure distribution port 33 or the second low-pressure distribution port 36 is connected to the plunger pump 4 and cooperates with the plunger pump 4 to enter the pump working condition or the motor working condition respectively.

[0037] The motor 1 pump group disclosed in this embodiment; uses the motor 1 and the plunger pump 4 to cooperate; can realize pump working condition and motor working condition; under the pump working condition, the motor 1 drives the plunger pump 4 to operate to realize the pumping of the driving liquid; under the motor working condition, the reflux force of the driving liquid can be used to drive the motor 1 to rotate to generate electricity; the potential energy of the external equipment is applied to the liquid pressure generated by the driving liquid, and the electric energy is stored; thus, energy recovery and utilization are realized; the energy utilization rate can be improved.

[0038] The structure for limiting the flow of the driving fluid at the low-pressure oil suction port 30a can adopt a variety of schemes; it is not limited to the only one; this embodiment is optimized and adopts one of the feasible options: the low-pressure oil suction port 30a is equipped with a first check valve 37a and limits the driving fluid from entering the low-pressure oil suction port 30a in one direction; when the pump is in operation, the first check valve 37a is opened; when the motor is in operation, the first check valve 37a is closed. When such a scheme is adopted; the first check valve 37a can be directly and detachably arranged in conjunction with the low-pressure oil suction port 30a; it can also form an integral structure with the low-pressure oil suction port 30a; when the first check valve 37a is opened, the driving fluid can pass normally.

[0039] The structure for limiting the flow of the driving fluid at the low-pressure oil return port 30c can also adopt a variety of schemes; it is not limited to the only one; this embodiment is optimized and adopts one of the feasible options: the low-pressure oil return port 30c is provided with a second one-way valve 37b; the second one-way valve 37b is used to limit the driving fluid from the first low-pressure distribution port 33 to the low-pressure oil return port 30c and discharge the valve body 3; when the pump is in operation, the second one-way valve 37b is closed; when the motor is in operation, the second one-way valve 37b is opened. When such a scheme is adopted; the first one-way valve 37a is closed while the second one-way valve 37b is opened; therefore, the refluxed driving fluid can only flow from the second one-way valve 37b to the low-pressure return port.

[0040] When the driving liquid delivered outward by the plunger pump 4 is insufficient, the output driving liquid can be increased by replenishing the liquid. This can be achieved through a variety of solutions, which are not limited to the only one. This embodiment is optimized and adopts one of the feasible options: the valve body 3 is provided with an oil replenishment channel; the oil replenishment channel extends from the low-pressure oil suction port 30a and connects to the high-pressure oil port 30b; the oil replenishment channel is provided with a third one-way valve 37c and the third one-way valve 37c is used to limit the driving liquid from the low-pressure oil suction port 30a to the high-pressure oil port 30b; when the pump is in operation and oil replenishment is required, the third one-way valve 37c is opened; when the motor is in operation, the third one-way valve 37c is closed. When such a solution is adopted, the third one-way valve 37c can control the opening and closing of the replenishment channel, and the driving liquid can only flow from the low-pressure oil suction port 30a to the high-pressure oil port 30b, thereby achieving replenishment. It should be noted that the system has oil replenishment conditions including when the system is in pump operation or shutdown. For example, when the pump is not working, in order to allow the plunger rod of the cylinder to move freely, the cylinder needs to be replenished with oil.

[0041] When the delivery pressure of the driving liquid is relatively high, it causes a high pressure condition in the valve body 3, and pressure relief is required to maintain the pressure balance of the driving liquid. The specific pressure relief structure can adopt a variety of schemes, which are not limited to the only one. This embodiment is optimized and adopts one of the feasible options: the valve body 3 is also provided with an overflow structure; the overflow structure is connected to the high-pressure oil port 30b and the low-pressure oil return port 30c respectively; the overflow structure limits the overflow of the driving liquid from the high-pressure oil port 30b and the low-pressure oil return port 30c to the outside through the overflow valve 35. When such a scheme is adopted, the overflow valve 35 is closed under normal conditions, and the overflow treatment of the high-pressure oil port 30b and the low-pressure oil return port 30c can be realized respectively.

[0042] When the plunger pump 4 is sucking and discharging oil, its action characteristics can be used to improve the efficiency of oil suction. This embodiment is optimized and adopts one of the feasible options: the valve body 3 is also provided with a second low-pressure distribution port 36; the second low-pressure distribution port 36 extends from the low-pressure oil suction port 30a to the plunger pump 4 of the plunger pump 4 and delivers the driving liquid to the plunger pump 4 of the plunger pump 4. When such a scheme is adopted, the second low-pressure distribution port 36 can fill the plunger pump 4 with the driving liquid; on the one hand, it can be used for the plunger 43 to suck and deliver oil; on the other hand, it can cool the plunger pump 4 to prevent the plunger pump 4 from overheating.

[0043] The structure of the plunger pump 4 can be in various forms; in order to improve the absorption and delivery of the oil by the plunger pump 4; this embodiment is optimized and adopts one of the feasible options: the plunger pump 4 includes a plunger 43 structure; the plunger 43 structure includes a cylinder 42 and a plunger 43 matched with the cylinder 42; the cylinder 42 is provided with a first oil inlet for receiving the driving liquid of the first low-pressure distribution port 33; the plunger 43 is provided with a second oil inlet for receiving the driving liquid in the cylinder 42. When such a scheme is adopted; an oil inlet channel is formed in the plunger 43; the driving liquid entering from the second oil inlet can pass through the oil inlet and enter the plunger 43 cavity; when the plunger pump 4 rotates and presses the plunger 43 into the plunger 43 cavity; the driving liquid in the plunger 43 cavity is pressed out and enters the high-pressure oil port 30b.

[0044] The valve body 3 is used to connect the motor 1 and the plunger pump 4; and the structure can be constructed in various forms; it is not limited to the only one; this embodiment is optimized and adopts one of the feasible options: the valve body 3 is provided with an axial hole in the middle; a bearing that matches the rotating shaft of the motor 1 is provided in the axial hole; a lubrication channel is provided at the low-pressure oil inlet and extends to the axial hole; the driving fluid enters the axial hole through the low-pressure oil inlet and is used to lubricate the bearing. When such a scheme is adopted; the number of bearings in the axial hole is several; and it includes bearings for radial support and axial abutment.

[0045] The structure in the plunger pump 4 can be optimized to improve the efficiency of pumping the driving fluid; this embodiment is optimized and adopts one of the feasible options: the plunger pump 4 also includes a slant plate structure; the slant plate 46 is provided with a sliding plate 44 that matches the plunger 43; the sliding plate 44 is provided with a plunger ball socket 442 and the end of the plunger 43 is matched in the plunger ball socket 442; the bottom of the plunger ball socket 442 is provided with an oil hole 443 and is connected and matched with the second oil inlet. When such a solution is adopted; the end of the plunger 43 is a spherical structure and fits with the plunger ball socket 442.

[0046] In order to better realize the oil absorption of the second oil inlet on the plunger 43, the structure of the sliding plate 44 is optimized. This embodiment adopts one of the feasible options: a sliding plate oil chamber 441 is provided on the end surface of the sliding plate 44 away from the plunger ball socket 442; the sliding plate oil chamber 441 is connected to the plunger ball socket 442 through the oil hole 443; and the area ratio of the oil hole 443 to the sliding plate oil chamber 441 is 0.4 to 0.9. When such a solution is adopted, the sliding plate oil chambers 441 are evenly spaced along the circumference.

[0047] According to the solution disclosed in the above embodiment, a specific case is cited here for illustration.

[0048] Case 1

[0049] like Figure 1 As shown, an embodiment of the energy recovery motor pump group of the present invention; in the embodiment shown; a motor is connected to a hydraulic plunger machine; the hydraulic plunger machine comprises a main shaft 2, a valve body 3 and a plunger pump 4; the valve body 3 is arranged at the shaft extension end of the main shaft; the plunger pump 4 is arranged at the tail end of the main shaft 2; the plunger pump 4 is fixedly connected to the valve body 3; the valve body 3 is provided with an oil inlet and outlet, an oil return port, a control valve, a main shaft bearing support part 32, a shaft sealing part 31 and an internal flow channel; the plunger pump 4 comprises a housing 47 , distribution pair, plunger pair and slide plate pair; the main shaft 2 passes through the valve body 3 and the distribution pair and cantilever supports the cylinder body 42; the slide plate pair includes a slide plate 44 and a swash plate 46; the slide plate 44 is an integral disc structure; the hydraulic plunger machine can work in pump mode and / or motor mode; the control valve includes at least one overflow valve and a one-way valve; the hydraulic plunger machine cooperates with the control valve to realize oil suction, oil discharge, oil return and oil replenishment functions on the valve body; the hydraulic plunger machine and the control valve are motor-coordinated to realize drive and / or energy recovery functions.

[0050] The motor 1 is a bidirectional motor with driving and generating functions; the motor is fixedly connected to the valve body; the main shaft is inserted into the shaft of the motor; when a certain rotation direction of the motor is designated as the driving function; the generating function is the reverse rotation direction; the servo controller realizes the control of this function conversion.

[0051] It should be noted that the end cover of the motor 1 is directly connected to the valve body 3; the valve body 3 and the plunger pump 4 are integrated in design; the valve body 3 serves as a carrier of the control valve; it also serves as a carrier for the oil distribution and oil inlet and outlet of the plunger pump 4; it also serves as a connection carrier connecting the motor 1 and the plunger pump 4; and the connection between the oil channels is achieved through the oil channels arranged inside the valve body; therefore, under the condition of realizing the driving and energy recovery functions, the motor pump group as a whole has the characteristics of compact structure and less piping.

[0052] like Figure 4 and Figure 7As shown; a low-pressure oil suction port 30a, a high-pressure oil port 30b and an oil return port 30c are provided on the valve body 3; the low-pressure oil suction port 30a and the high-pressure oil port 30b are respectively connected to the first low-pressure distribution port 33 and the high-pressure distribution port 34 of the valve body 3; the oil return port 30c is connected to the low-pressure oil suction port 30a through the internal flow channel of the valve body 3.

[0053] like Figures 4 to 7 As shown; at least one overflow valve 35 is also provided on the valve body 3; the inlet of the overflow valve 35 is connected with the high-pressure oil port 30b through the second oil hole 382 and the third oil hole 383; the outlet of the overflow valve 35 is connected with the return oil port 30c through the first oil hole 381; when the oil pressure of the high-pressure oil port 30b exceeds the set pressure of the overflow valve 35; the overflow valve 35 opens to maintain the pressure near the set pressure.

[0054] like Figure 7 , Figure 8 As shown; at least three one-way valves are also arranged on the valve body 3; the low-pressure oil suction port 30a is connected with the first low-pressure distribution port of the valve body 3 through the first one-way valve 37a; it plays a one-way oil suction role; the oil can only enter from the low-pressure oil suction port (S port); it cannot be discharged from the low-pressure oil suction port (S port); the low-pressure oil suction port 30a is connected with the high-pressure oil port 30b through the first one-way valve 37a and the third one-way valve 37c, which plays an oil replenishment role; the oil replenishment path, low-pressure oil suction port → first one-way valve 37a → third one-way valve 37c → high-pressure oil port 30b; it cannot flow in the opposite direction; the return oil port 30c is connected with the first low-pressure distribution port 33 of the valve body 3 through the second one-way valve 37b; it plays an oil return role; the return oil flows out from the pump port through the second one-way valve 37b and the oil return port and flows back to the oil tank; it cannot flow in the opposite direction.

[0055] Among them; such as Figure 7 As shown; the inlet of the third one-way valve 37c is connected to the low-pressure oil suction port 30a through the sixth oil hole 386; the outlet of the third one-way valve 37c is connected to the low-pressure oil suction port 30a through the fourth oil hole 384 and the fifth oil hole 385.

[0056] It should be noted that the first one-way valve 37a and the second one-way valve 37b are not Figure 1 to Figure 7 The reason is that the first check valve 37a and the second check valve 37b can be integrated in the connection ports of the low-pressure oil suction port 30a and the oil return port 30c respectively; this structure is simpler. Alternatively, the first check valve 37a and the second check valve 37b can also be fixed on the low-pressure oil suction port 30a and the oil return port 30c by plug-in type.

[0057] Combine the following Figure 1 , Figure 8 Explain the working principle of the hydraulic system of the motor pump unit:

[0058] (1) When the motor pump unit is working in the driving function; the motor 1 drives the hydraulic plunger machine; the hydraulic plunger machine works in the pumping condition; the first one-way valve 37a is opened; the hydraulic plunger machine sucks oil through the low-pressure oil suction port 30a and discharges oil through the high-pressure oil port 30b; the second one-way valve 37b and the third one-way valve 37c are closed.

[0059] (2) When the motor pump unit is operating in the power generation function; the hydraulic plunger machine receives the high-pressure oil from the actuator; the hydraulic plunger machine operates in the motor mode and runs in reverse; the hydraulic plunger machine drives the motor to generate electricity; the second one-way valve 37b is opened; the hydraulic plunger machine returns oil through the second one-way valve 37b and the return oil port 30c; the first one-way valve 37a and the third one-way valve 37c are closed.

[0060] (3) When the system needs to replenish oil, the first one-way valve 37a and the third one-way valve 37c are opened; low-pressure oil is replenished from the first one-way valve 37a and the third one-way valve 37c; the second one-way valve 37b is closed.

[0061] like Figure 3 and Figure 4 As shown; reduce the noise of the hydraulic plunger machine; set the second low-pressure distribution port 36 opening to the cavity of the housing 47 on the valve body 3; the second low-pressure distribution port 36 connects the low-pressure oil suction port 30a and the cavity of the housing. When working; after the oil enters through the low-pressure oil suction port 30a; one way passes through the internal flow channel of the valve body 3 and the first low-pressure distribution port 33 of the distribution plate to enter the cylinder plunger hole; one way passes through the second low-pressure distribution port 36 to enter the housing cavity of the plunger pump 4 and enters the cylinder plunger hole through the oil hole and the plunger center hole.

[0062] In order to make the thrust bearing 21 and the needle bearing 22 installed on the valve body more durable, a seventh oil hole 387 is provided on the low-pressure oil suction port 30a; the seventh oil hole 387 connects the bearing cavity of the valve body 3 and the low-pressure oil suction port 30a; the seventh oil hole 387 allows the oil to flow through the needles of the thrust bearing 21 and the needle bearing 22, thereby playing a role in cooling and lubricating.

[0063] When the sliding plate pair also serves as an oil suction passage; a plurality of sliding plate oil chambers 441 are provided on one end surface of the sliding plate 44 in contact with the swash plate 46; an oil hole 442 communicating with the oil chamber is provided on the sliding plate ball socket side; to ensure that the plunger 1 and the sliding plate ball socket 32 ​​have good oil suction capacity and sufficient residual thrust; the area of ​​the oil hole 442 and the area of ​​the sliding plate oil chamber 441 are controlled between 0.4 and 0.9; Fig. 9 shown.

[0064] like Figure 2 , Fig. 9 , Fig.10As shown; one end face of the sliding plate 44 is provided with a plurality of waist-shaped oil chambers 441 and supported on the swash plate 4 to form a static pressure support; the other end face of the sliding plate 44 is provided with a plurality of plunger ball sockets 442 and used to connect the plunger ball head of the plunger 43; a sliding plate center hole 444 is provided in the middle of the sliding plate; at least one oil groove 451 is provided on the swash plate positioning seat 45 along the outer periphery of the swash plate 46 downward; the oil groove 451 introduces high-pressure oil from the drainage hole 452 in the sliding plate pair; to offset most or all of the lateral component force of the sliding plate 44 acting on the swash plate positioning seat 45.

[0065] The above are the implementation methods listed in this embodiment; however, this embodiment is not limited to the above optional implementation methods; those skilled in the art can arbitrarily combine the above methods to obtain other various implementation methods; anyone can derive other various implementation methods under the inspiration of this embodiment. The above specific implementation methods should not be understood as limiting the protection scope of this embodiment; the protection scope of this embodiment shall be based on the definition in the claims.

Claims

1. A motor pump unit capable of recovering energy, characterized in that: The invention comprises a motor (1) and a plunger pump (4); the motor (1) and the plunger pump (4) are connected via a valve body (3) and a driving fluid is transmitted via the valve body (3); a rotating shaft of the motor (1) passes through the valve body (3) and is connected to drive a cylinder body (42) of the plunger pump (4) to rotate synchronously; a low-pressure oil suction port (30a) is provided on the valve body (3) and the low-pressure oil suction port (30a) transmits the driving fluid to the cylinder body (42) of the plunger pump (4) in one direction via a first low-pressure distribution port (33); and the valve body ( A high-pressure oil port (30b) is provided on the valve body (3), and the plunger pump (4) unidirectionally delivers driving fluid to the high-pressure oil port (30b) through the first high-pressure distribution port (34); a low-pressure return oil port (30c) is also provided on the valve body (3) and is connected to the low-pressure oil suction port (30a), and the connection is controlled by the valve body (3); the first low-pressure distribution port (33) or the second low-pressure distribution port (36) is connected to the plunger pump (4) and respectively cooperates with the plunger pump (4) to enter the pump working state or the motor working state.

2. The energy-recoverable motor pump assembly according to claim 1, characterized in that: The low-pressure oil suction port (30a) is provided with a first one-way valve (37a) to limit the one-way entry of the driving fluid into the low-pressure oil suction port (30a). When the pump is in operation, the first one-way valve (37a) is opened, and when the motor is in operation, the first one-way valve (37a) is closed.

3. The energy-recoverable motor pump assembly according to claim 1, characterized in that: The low-pressure oil return port (30c) is provided with a second one-way valve (37b) for limiting the driving fluid from flowing from the first low-pressure distribution port (33) to the low-pressure oil return port (30c) and being discharged from the valve body (3). When the pump is in operation, the second one-way valve (37b) is closed, and when the motor is in operation, the second one-way valve (37b) is opened.

4. The energy-recoverable motor pump assembly according to claim 1, characterized in that: The valve body (3) is provided with an oil replenishing passage, which extends from the low-pressure oil suction port (30a) and is connected to the high-pressure oil port (30b). The oil replenishing passage is provided with a third one-way valve (37c) and the third one-way valve (37c) is used to limit the driving fluid from the low-pressure oil suction port (30a) to be replenished into the high-pressure oil port (30b). When oil replenishment is required, the third one-way valve (37c) is opened, and when the motor is in operation, the third one-way valve (37c) is closed.

5. The energy-recoverable motor pump assembly according to claim 1, characterized in that: The valve body (3) is also provided with an overflow structure, which is connected to the high-pressure oil port (30b) and the low-pressure oil return port (30c) respectively. The overflow structure limits the driving fluid from overflowing outward from the high-pressure oil port (30b) and the low-pressure oil return port (30c) through the overflow valve (35).

6. The energy-recoverable motor pump assembly according to claim 1, characterized in that: The valve body (3) is also provided with a second low-pressure distribution port (36), which extends from the low-pressure oil suction port (30a) to communicate with the plunger pump (4) and transports driving fluid into the plunger pump (4).

7. The energy-recoverable motor pump assembly according to claim 6, characterized in that: The plunger pump (4) comprises a plunger (43) structure, the plunger (43) structure comprises a cylinder body (42) and a plunger (43) matched with the cylinder body (42), the cylinder body (42) is provided with a first oil inlet and is connected to the first low-pressure distribution port (33), and the plunger (43) is provided with a second oil inlet and is connected to the plunger pump housing cavity.

8. The energy-recoverable motor pump assembly according to claim 1, characterized in that: The valve body (3) is provided with an axial hole in the middle, and a bearing matched with the rotating shaft of the motor (1) is provided in the axial hole; a lubrication channel is provided at the low-pressure oil inlet and extends to the axial hole, and the driving fluid enters the axial hole through the low-pressure oil inlet and is used to lubricate the bearing.

9. The energy-recoverable motor pump assembly according to claim 7, characterized in that: The plunger pump (4) further comprises a swash plate structure, wherein a sliding plate (44) matching with the plunger (43) is arranged on the swash plate (46), a plunger ball socket (442) is arranged on the sliding plate (44) and the end of the plunger (43) is matched in the plunger ball socket (442), and an oil hole (443) is arranged at the bottom of the plunger ball socket (442) and is connected and matched with the second oil inlet.

10. The energy-recoverable motor pump assembly according to claim 9, characterized in that: A sliding plate oil chamber (441) is provided on the end surface of the sliding plate (44) away from the plunger ball socket (442); the sliding plate oil chamber (441) is connected to the plunger ball socket (442) through an oil hole (443); and the area ratio of the oil hole (443) to the area of ​​the sliding plate oil chamber (441) is 0.4 to 0.9.

Images