Novel variable pump free of thrust bearing and control method

Abstract

The invention discloses a thrust-bearing-free novel variable pump and a control method, the thrust-bearing-free novel variable pump comprises a pump shell, and a fluid input end and a fluid output end are respectively formed at two opposite ends of the pump shell; the main shaft is rotationally connected into the pump shell, and a first impeller is fixedly arranged on the main shaft; a shaft sleeve is arranged on the main shaft in a key connection mode, a second impeller is fixedly arranged on the shaft sleeve, the second impeller and the first impeller are distributed in a staggered mode to form a fluid pressurizing cavity, and the fluid pressurizing cavity is communicated with the fluid input end and the fluid output end; the sliding between the shaft sleeve and the main shaft is used for replacing the direct sliding between the existing bearing and the main shaft, the first impeller is directly fixed on the shaft sleeve, so that the first impeller does not bear the axial thrust generated during rotation, and meanwhile, the direct friction between the bearing acting on the impeller and the main shaft can be avoided; and the influence on variable control of the pump body due to transverse movement caused by abrasion of the bearing is avoided.

Description

Technical Field

[0001] This invention belongs to the technical field, specifically relating to a novel variable pump without thrust bearings and its control method. Background Technology

[0002] Traditional variable displacement pumps typically use thrust bearings to support the main shaft rotation and bear the axial thrust generated during impeller operation. When the impeller is moved to control fluid flow, the thrust bearing usually slides directly against the main shaft. This sliding friction between the thrust bearing and the main shaft leads to energy loss and reduces pump efficiency. Under long-term high-load operation, the bearings are prone to wear and require frequent maintenance. Furthermore, traditional mechanical structures cannot adjust the axial clearance in real time according to different pump output conditions, resulting in low flow regulation accuracy, especially prone to pressure fluctuations under variable load conditions.

[0003] Therefore, there is an urgent need for a new structure that can control the axial displacement of the impeller, reduce friction, and improve dynamic response capability. Summary of the Invention

[0004] In order to solve the above-mentioned problems in the existing technology, the present invention aims to provide a novel variable pump and control method without thrust bearing.

[0005] The technical solution adopted in this invention is a novel variable pump without thrust bearings, comprising:

[0006] The pump casing has a fluid inlet and a fluid outlet at opposite ends.

[0007] A main shaft is rotatably connected inside the pump casing, and a first impeller is fixedly mounted on it; a bushing is keyed to the main shaft, and a second impeller is fixedly mounted on the bushing; the second impeller and the first impeller are staggered to form a fluid pressurization chamber, and the fluid pressurization chamber is connected to the fluid input end and the fluid output end;

[0008] An impeller propulsion mechanism is used to push the bushing to slide on the main shaft in order to control the volume change of the fluid pressurization chamber.

[0009] In a preferred embodiment of the present invention, the pump housing has a first cavity communicating with the fluid input end and a second cavity communicating with the fluid output end; both the first cavity and the second cavity are respectively communicating with the fluid pressurization chamber.

[0010] In a preferred embodiment of the present invention, an mounting sleeve is fixedly provided on the pump casing, and a vertical plate is fixedly provided at the bottom of the mounting sleeve; the main shaft is rotatably connected inside the mounting sleeve, and an installation space for the impeller propulsion mechanism is formed between the mounting sleeve and the main shaft.

[0011] As a preferred embodiment of the present invention, the impeller propulsion mechanism includes:

[0012] The hydraulic cylinder is installed in the installation space and rotates synchronously with the main shaft. Its fixed end is fixedly connected to the main shaft, and its output end abuts against one end of the bushing.

[0013] An oil supply pipe, located inside the main shaft, is used to supply oil to the hydraulic cylinder;

[0014] A hydraulic control system is used for metered oil supply or return to the oil cylinder.

[0015] In a preferred embodiment of the present invention, the hydraulic cylinder includes a fixed ring fixedly connected to the main shaft and a pusher plate slidably sleeved on the fixed ring. The pusher plate is rotatably connected to the mounting sleeve. A left oil chamber and a right oil chamber are formed between the fixed ring and the pusher plate through a partition. Both the left oil chamber and the right oil chamber are connected to the oil supply pipe. A wool felt is provided between the fixed ring and the mounting sleeve. The wool felt is used for sealing the rotation between the mounting sleeve and the pusher plate.

[0016] In a preferred embodiment of the present invention, the oil supply pipe includes a left cavity oil inlet pipe and a right cavity oil inlet pipe located within the main shaft. One end of the left cavity oil inlet pipe is connected to the left oil cavity, and the other end is connected to a rotary joint. The rotary joint is fixedly connected to the mounting sleeve. One end of the right cavity oil inlet pipe is connected to the right oil cavity, and the other end is connected to the rotary joint.

[0017] In a preferred embodiment of the present invention, a leakage groove is formed between the fixing ring and the mounting sleeve, the leakage groove being used to collect hydraulic oil leaking from the cylinder; a return pipe is formed inside the main shaft, one end of which is a closed end and the other end is connected to the rotary joint, one end of the return pipe being connected to the right oil chamber for collecting hydraulic oil leaking from the cylinder; a return hole is provided on the main shaft, one end of the return hole being connected to the return pipe and the other end extending through to the push plate.

[0018] As a preferred embodiment of the present invention, the hydraulic control system includes an oil supply component connected to the end of the rotary joint away from the main shaft, pressure sensors disposed in the left and right oil chambers, and a linear displacement sensor located on the partition plate to detect the axial displacement of the propulsion plate relative to the fixed ring. The oil supply component is used for alternating oil supply or return to the left and right oil chambers.

[0019] As a preferred embodiment of the present invention, a novel variable pump control method without thrust bearings, using the aforementioned novel variable pump without thrust bearings, includes the following steps:

[0020] a) The hydraulic pressure is monitored in real time by pressure sensors installed in the left and right oil chambers, the axial position of the linear displacement sensor relative to the fixed ring is monitored by the linear displacement sensor installed in the push plate, and the pumping volume is monitored by the flow sensor at the fluid output end.

[0021] b) A model predictive control algorithm is adopted to establish a dynamic model based on the fluid dynamics of the fluid booster chamber, the hydraulic oil flow and the propeller plate mechanics. The propeller plate position and pumping volume are predicted within one second, the oil supply flow rate of the proportional control valve of the oil supply component is optimized, and the propeller plate movement is controlled to adjust the volume of the fluid booster chamber.

[0022] c) The controller processes the sensor data and generates a control signal for the proportional control valve of the oil supply component, thereby realizing the staggered oil supply or return between the left and right oil chambers.

[0023] d) Monitor hydraulic oil leakage through flow sensors in the leakage channel and return pipe, and dynamically adjust the oil supply to compensate for the loss;

[0024] The controller is a programmable logic controller or a microcontroller that runs on a real-time operating system.

[0025] As a preferred embodiment of the present invention, a safety and stability mechanism is also included, comprising the following steps:

[0026] a) Set the maximum pressure thresholds for the left and right oil chambers to prevent overpressure damage to the feed plate or spindle;

[0027] b) Vibration is monitored by an accelerometer mounted on the sleeve, and a safety shutdown is triggered when the threshold is exceeded;

[0028] c) In case of abnormal conditions, enter safety mode, stop the propulsion plate movement and maintain neutral pressure in the oil chamber.

[0029] The beneficial effects of this invention are as follows:

[0030] This invention is a novel variable displacement pump without thrust bearings. It replaces the direct sliding between the existing bearing and the main shaft with the sliding between the bushing and the main shaft. Since the first impeller is directly fixed on the bushing, it is exempt from the axial thrust generated during rotation. At the same time, it avoids direct friction between the bearing acting on the impeller and the main shaft, and avoids lateral movement caused by bearing wear that affects the variable displacement control of the pump body. In addition, since the impeller propulsion mechanism can precisely control the movement of the first impeller, it can improve the precision control of the pumped fluid volume.

[0031] By setting a dual-chamber hydraulic control cylinder in the impeller propulsion mechanism, the synchronous, equal, and staggered operation of hydraulic oil supply and return between the left and right oil chambers is utilized to drive the impeller to slide on the main shaft by pushing the bushing. At the same time, the synchronous rotation of the main shaft and the impeller can be maintained. By utilizing the fixed connection between the impeller and the bushing, the lateral movement of the impeller is achieved through the movement between the bushing and the main shaft, thereby reducing the service life of the bearings acting on the impeller rotation.

[0032] The control method significantly improves the performance of the thrust-free variable pump through real-time monitoring, MPC algorithm, staggered oil supply and dynamic leakage compensation, and is suitable for high-precision and high-reliability hydraulic system applications. Attached Figure Description

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and specific implementation methods.

[0034] Figure 1 This is a schematic diagram of the structure of the present invention;

[0035] Figure 2 This is a front cross-sectional view of the present invention;

[0036] Figure 3 This is a side cross-sectional view of the present invention;

[0037] Figure 4 This is a schematic diagram of the internal structure of the present invention;

[0038] Figure 5 This is a partial structural schematic diagram of the present invention.

[0039] In the diagram: 1. Pump casing; 2. Main shaft; 3. Impeller propulsion mechanism; 11. Fluid input end; 12. Fluid output end; 13. First cavity; 14. Second cavity; 21. First impeller; 22. Second impeller; 23. Shaft sleeve; 24. Mounting sleeve; 25. Vertical plate; 26. Installation space; 31. Oil cylinder; 32. Oil supply pipe; 211. Fluid pressurization chamber; 311. Fixing ring; 312. Propulsion plate; 313. Partition plate; 314. Left oil cavity; 315. Right oil cavity; 316. Leakage groove; 317. Return hole; 318. Wool felt; 319. Return pipe; 321. Left cavity oil inlet pipe; 322. Right cavity oil inlet pipe; 323. Rotary joint. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0042] The following is combined Figure 1-5 This invention describes a novel variable displacement pump without thrust bearings, comprising:

[0043] Pump casing 1, with fluid inlet 11 and fluid outlet 12 formed at opposite ends;

[0044] A main shaft 2 is rotatably connected inside the pump casing 1, and a first impeller 21 is fixedly mounted on it. A bushing 23 is keyed to the main shaft 2, and a second impeller 22 is fixedly mounted on the bushing 23. The second impeller 22 and the first impeller 21 are alternately distributed to form a fluid boosting chamber 211. The fluid boosting chamber 211 is connected to both the fluid input end 11 and the fluid output end 12. Fluid enters the pump casing 1 through the fluid input end 11 and is boosted by the main shaft 2 and its synchronous rotation to increase the pumping pressure at the fluid output end 12. The first impeller... The impeller 21 can move relative to the second impeller 22, causing the blades on the impeller to interleave. By changing the position between the first impeller 21 and the second impeller 22, on the one hand, the volume of the fluid boosting chamber 211 formed between the first impeller 21 and the second impeller 22 can be changed, thereby increasing the amount of fluid in the pump body at the same time and realizing the fluid output variable of the pump body. On the other hand, the contact surface between the first impeller 21 and the second impeller 22 and the fluid boosting can be changed, thereby improving the boosting effect on the fluid in the fluid boosting chamber 211 at the same rotation speed of the main shaft 2 and realizing the output variable control of the pump body.

[0045] The impeller propulsion mechanism 3 is used to push the bushing 23 to slide on the main shaft 2 to control the volume change of the fluid pressurization chamber 211. The impeller propulsion mechanism 3 pushes the bushing 23 to move, so that the bushing 23 drives the main shaft 2 to move synchronously. The movement of the bushing 23 changes the relative position between the first impeller 21 and the second impeller 22, avoiding the energy loss caused by the sliding friction between the thrust bearing and the main shaft 2 in the traditional structure, thereby improving the efficiency of the pump body and making it suitable for long-term high-load operation. It also avoids the need for frequent maintenance of the thrust bearing. The impeller propulsion mechanism 3 can achieve ultra-high precision adjustment of the relative position between the first impeller 21 and the second impeller 22, thereby changing the technical problem in the traditional mechanical structure that the axial clearance cannot be adjusted in real time according to the working conditions, resulting in low flow regulation accuracy, especially the pressure fluctuation under variable load conditions.

[0046] Please refer to Figures 1-3 As shown, the pump casing 1 has a first cavity 13 connected to the fluid input end 11 and a second cavity 14 connected to the fluid output end 12. The first cavity 13 and the second cavity 14 are both connected to the fluid boosting chamber 211. Fluid enters the first cavity 13 through the pump casing 1. Under the action of the impeller rotation, the fluid in the first cavity 13 enters the boosting chamber 211 from one end of the impeller. Under the high-speed rotation of the impeller and the flow guidance, the fluid boosting chamber 211 finally outputs from the fluid output end 12.

[0047] Please refer to Figures 4-5 As shown, a mounting sleeve 24 is fixedly provided on the pump casing 1, and a vertical plate 25 is fixedly provided at the bottom of the mounting sleeve 24; the main shaft 2 is rotatably connected inside the mounting sleeve 24, and an installation space 26 for the impeller propulsion mechanism 3 is formed between the mounting sleeve 24 and the main shaft 2. The mounting sleeve 24 is fixedly connected to the pump casing 1, and the vertical plate 25 fixedly provided on the mounting sleeve 24 is used for the pump body to be placed stably on the plane. An installation space 26 for the impeller propulsion mechanism 3 is formed between the main shaft 2 and the mounting sleeve 24. The fixed end of the impeller propulsion mechanism 3 is fixedly connected to the mounting shell, and its output end abuts against one end of the bushing 23. The impeller propulsion mechanism 3 can be used to push the bushing 23 to move on the main shaft 2, thereby driving the first impeller 21 to move closer to or away from the second impeller 22, thereby changing the fluid pressurization chamber 211 formed between the first impeller 21 and the second impeller 22.

[0048] Please refer to Figure 5 As shown, the impeller propulsion mechanism 3 includes:

[0049] The hydraulic cylinder 31 is installed in the installation space 26 and rotates synchronously with the main shaft 2. Its fixed end is fixedly connected to the main shaft 2, and its output end abuts against one end of the bushing 23. The hydraulic cylinder 31 drives the bushing 23 to slide along the main shaft 2. The sliding between the bushing 23 and the main shaft 2 replaces the sliding of the transmission thrust bearing, so that the bearing on the main shaft 2 only needs to be used to assist the rotation of the impeller and does not need to bear the axial thrust generated by the rotation of the impeller. It also avoids the direct lateral sliding between the impeller and the main shaft 2, effectively reducing the wear of the impeller bearing. At the same time, the impeller propulsion mechanism 3 drives the impeller to move. The hydraulic pressure of the hydraulic cylinder 31 can be used to precisely control the movement distance of the first impeller 21 on the second impeller 22, so as to achieve precise control of the pumped fluid volume.

[0050] The oil supply pipe 32 is located inside the main shaft 2 and is used to supply oil to the oil cylinder 31. The oil supply pipe 32 is used to supply or return oil to the oil cylinder 31, so that the output end of the oil cylinder 31 drives the bushing 23 to move along the length direction of the main shaft 2.

[0051] The hydraulic control system is used for the quantitative oil supply or return of the oil cylinder 31. The hydraulic control system is used to detect and control the oil pressure supply to achieve precise control of the moving distance of the first impeller 21.

[0052] Please refer to Figure 5As shown, the hydraulic cylinder 31 includes a fixed ring 311 fixedly connected to the main shaft 1, and a push plate 312 slidably sleeved on the fixed ring 311. The push plate 312 is keyed to the fixed ring 311. The push plate 312 and the fixed ring 311 rotate synchronously with the main shaft. In addition, the push plate 312 can slide relative to the fixed ring 311. The push plate 312 is rotatably connected to the mounting sleeve 24. A left oil chamber 314 and a right oil chamber 315 are formed between the fixed ring 311 and the push plate 312 through a partition 313. Both the left oil chamber 314 and the right oil chamber 315 are connected to the oil supply pipe 32. A dual-chamber system is provided in the cylinder 31, with the left chamber 314 and the right chamber 315 supplied with hydraulic oil via separate pipelines. During the movement of the first impeller 21, when it needs to move closer to the second impeller 22, the hydraulic control system receives a signal and controls one of the oil supply pipes 32 to supply oil pressure to the left chamber 314. At this time, the pusher plate 312 moves to the right, pushing the bushing 23 to move to the right along the length of the main shaft 2. Because the impellers of the first impeller 21 and the second impeller 22 are interleaved, the movement to the right... When the first impeller 21 moves to the right, the volume of the fluid boosting chamber 211 formed between the first impeller 21 and the second impeller 22 gradually decreases, and the contact area between the impeller and the fluid gradually decreases, resulting in a decrease in the boosting pressure of the impeller on the fluid. This allows for control of the pumping volume or pumping pressure value of the fluid. Since the hydraulic cylinder 31 is controlled by hydraulic pressure, the accuracy of the distance movement between the first impeller 21 and the second impeller 22 is effectively improved, effectively controlling the output of the pump body. At the same time, it avoids the influence of the direct contact movement between the bearing and the main shaft 2 when the first impeller 21 moves laterally.

[0053] Please refer to Figures 1-4 As shown, the oil supply pipe 32 includes a left cavity oil inlet pipe 321 and a right cavity oil inlet pipe 322 located within the main shaft 2. One end of the left cavity oil inlet pipe 321 is connected to the left oil cavity 314, and the other end is connected to a rotary joint 323. The rotary joint 323 is fixedly connected to the mounting sleeve 24. One end of the right cavity oil inlet pipe 322 is connected to the right oil cavity 315, and the other end is connected to the rotary joint 323. The rotary joint 323 is used to maintain synchronous rotation with the main shaft 2 while supplying or returning oil to the left oil cavity 314 through the left cavity oil inlet pipe 321 and supplying or returning oil to the right oil cavity 315 through the right cavity oil inlet pipe 322, so as to ensure that the left oil cavity 314 and the right oil cavity 315 are synchronously supplied and returned in staggered amounts.

[0054] Please refer to Figure 5As shown, a leakage groove 316 is formed between the fixed ring 311 and the mounting sleeve 24. The leakage groove 316 collects the hydraulic oil leaking from the cylinder 31. A return pipe 319 is formed inside the main shaft 2. One end of the return pipe 319 is closed, and the other end is connected to the rotary joint 323. One end of the return pipe 319 is connected to the right oil chamber 315 to collect the hydraulic oil leaking from the cylinder 31. A return hole 317 is provided on the main shaft 2. One end of the return hole 317 is connected to the return pipe 319, and the other end extends through to the push plate 312. When the cylinder (31) slides in the drive sleeve 23, there are gaps between the sliding parts. The gaps are sealed by a sealing ring. However, some fluid still leaks.

[0055] Please refer to Figure 5 As shown, a wool felt 318 is provided between the fixing ring 311 and the mounting sleeve 24. The wool felt 318 is used to seal the rotation between the mounting sleeve 24 and the push plate 312. The wool felt prevents the oil pressure leaking in the left oil cavity 314 from leaking out of the wool felt 318, and instead allows it to leak through the leakage groove 316.

[0056] Please refer to Figures 4-5 As shown, the hydraulic control system includes an oil supply component connected to the end of the rotary joint 323 away from the main shaft 2. The oil supply component is used to synchronously supply or return oil to the left oil chamber 314 and the right oil chamber 315 in an alternating manner. The oil supply component is a conventional technology and consists of a hydraulic oil tank, an oil pump, and an accumulator. It achieves the change in volume in the left oil chamber 314 or the right oil chamber 315 by conveying or drawing hydraulic oil through the left chamber inlet pipe 321 or the right chamber inlet pipe 322.

[0057] Please refer to Figures 1-4 As shown, the hydraulic control system includes an oil supply component connected to the end of the rotary joint (323) away from the main shaft (2), pressure sensors disposed in the left and right oil chambers, and a linear displacement sensor located on the partition plate to detect the axial displacement of the push plate relative to the fixed ring. The oil supply component is used for the staggered oil supply or return of the left oil chamber (314) and the right oil chamber (315).

[0058] A novel variable pump control method without thrust bearings includes the following steps:

[0059] a) The hydraulic pressure is monitored in real time by pressure sensors installed in the left oil chamber (314) and right oil chamber (315), the axial position of the plate relative to the fixed ring (311) is monitored by a linear displacement sensor installed in the push plate (312), and the pumping volume is monitored by a flow sensor at the fluid output end (12).

[0060] b) Using the Model Predictive Control (MPC) algorithm, a dynamic model is established based on the fluid dynamics of the fluid booster chamber (211), the hydraulic oil flow and the propeller plate mechanics. The propeller plate position and pumping volume are predicted within 0.1-1 seconds. The oil supply flow rate of the proportional control valve of the oil supply component is optimized, and the propeller plate (312) is moved to adjust the volume of the fluid booster chamber (211).

[0061] c) The controller processes the sensor data and generates a control signal for the proportional control valve of the oil supply component, thereby realizing the alternating oil supply or return of the left oil chamber (314) and the right oil chamber (315);

[0062] d) Monitor hydraulic oil leakage through flow sensors in the leakage groove (316) and return pipe (319) and dynamically adjust the oil supply to compensate for the loss;

[0063] The controller is a programmable logic controller (PLC) or a microcontroller, running on a real-time operating system.

[0064] 10. The control method according to claim 9, characterized in that it further includes a safety and stability mechanism, comprising the following steps:

[0065] a) Set the maximum pressure threshold for the left oil chamber (314) and the right oil chamber (315) to prevent overpressure damage to the propeller plate or spindle;

[0066] b) Vibration is monitored by the accelerometer on the mounting sleeve (24), and a safety shutdown is triggered when the threshold is exceeded;

[0067] c) In case of abnormal conditions, enter safety mode, stop the propulsion plate movement and maintain neutral pressure in the oil chamber.

[0068] In the real-time monitoring of the variable pump control method, pressure sensors are installed in the left oil chamber (314) and right oil chamber (315) to monitor the hydraulic oil pressure in real time; a linear displacement sensor is installed on the push plate (312) to monitor its axial displacement relative to the fixed ring (311); and a flow sensor is installed at the fluid output end (12) to monitor the pumping rate.

[0069] The model predictive control (MPC) algorithm can be any algorithm in the prior art. In this embodiment, the MPC algorithm is used to establish a dynamic model based on the fluid dynamics of the fluid booster chamber (211), the hydraulic oil flow and the propulsion plate mechanics. The model includes dynamic model establishment, prediction and optimization and control execution.

[0070] The dynamic model establishment includes:

[0071] Fluid dynamics model: Based on Bernoulli's equation and continuity equation, the dynamic relationship between pressure and flow rate in the fluid pressurization chamber (211) is described, taking into account fluid compressibility and viscous resistance.

[0072] Hydraulic oil flow model: Based on the flow characteristics of the proportional control valve of the oil supply component, the pressure-flow relationship between the left oil chamber (314) and the right oil chamber (315) is established. The input is the valve opening and the output is the oil chamber pressure.

[0073] Mechanical model of the propulsion plate: Based on Newton's second law, the motion characteristics of the propulsion plate (312) under the influence of hydraulic oil pressure, friction and inertial force are described.

[0074] Prediction and optimization include:

[0075] The prediction time window is 0.11 seconds, the step size is 0.01 seconds, and the prediction of the propulsion plate position and pumping volume is used.

[0076] Optimization objective: Minimize the deviation between the pumping volume and the target flow rate, while limiting the displacement velocity and acceleration of the propeller plate.

[0077] The optimization variable is the opening degree of the proportional control valve for the fuel supply component. A quadratic programming solver is used to calculate the optimal control sequence, updating the control signal every 0.01 seconds.

[0078] Control execution: Based on the optimization results, adjust the opening of the proportional control valve to control the hydraulic oil to enter the left oil chamber (314) or the right oil chamber (315), push the propulsion plate (312) to move, and adjust the volume of the fluid booster chamber (211).

[0079] In the staggered oil supply and return controller, a PLC or microcontroller runs on a real-time operating system, processes sensor data, and generates control signals for the proportional control valve. This achieves staggered oil supply or return between the left oil chamber (314) and the right oil chamber (315): when the fluid pressurization chamber volume needs to be increased, the left oil chamber supply is increased, and the right oil chamber returns oil. When the fluid pressurization chamber volume needs to be decreased, the right oil chamber supply is increased, and the left oil chamber returns oil.

[0080] Leakage compensation monitors the hydraulic oil leakage through flow sensors in the leakage groove (316) and return pipe (319). The controller dynamically adjusts the oil supply of the proportional control valve according to the leakage amount to compensate for the loss and maintain stable oil chamber pressure.

[0081] To ensure the safe and stable operation of the system, overvoltage protection is provided, including:

[0082] The maximum pressure thresholds for the left oil chamber (314) and the right oil chamber (315) are set. When the pressure sensor detects that the threshold is exceeded, the controller immediately closes the proportional control valve and stops the oil supply to prevent damage to the propeller plate or the spindle.

[0083] Vibration monitoring: An accelerometer is installed on the mounting sleeve (24) to monitor system vibration and set a threshold. When the vibration exceeds the threshold, a safety shutdown is triggered, the controller cuts off the oil supply and issues an alarm.

[0084] Safety Mode: When an anomaly is detected, such as a sensor malfunction or a sudden pressure change, the controller enters safety mode, stops the propeller plate from moving, maintains neutral pressure in the left and right oil chambers, and avoids system damage.

[0085] Working principle of this invention:

[0086] When controlling the pump body variables, the impeller propulsion mechanism 3 drives the bushing 23 to slide along the length of the main shaft 2, thereby changing the synchronous movement of the first impeller 21, which is fixedly connected to the bushing 23, and the bushing 23 on the main shaft 2. This causes a change in the relative position between the first impeller 21 and the second impeller 22. Since a fluid pressurization chamber 211 is formed between the first impeller 21 and the second impeller 22, the change in the relative position between the first impeller 21 and the second impeller 22 can realize the change of the fluid in the pump body. At the same time, since the blades of the first impeller 21 and the second impeller 22 are staggered, when the position of the first impeller 21 and the second impeller 22 changes, the contact surface of the impeller blades acting on the fluid pressurization changes, thereby changing the fluid output under the rotation of the same main shaft 2.

[0087] When the first impeller 21 needs to move towards the second impeller 22, one end of the oil supply pipe 32 is connected to the oil supply component. The oil supply component is independently connected to the left cavity oil inlet pipe 321 and the right cavity oil inlet pipe 322 through the oil supply pipe 32. Oil pressure is injected into the left oil cavity 314 through the left cavity oil inlet pipe 321. At the same time, the hydraulic oil in the left oil cavity 314 flows back through the right cavity oil inlet pipe 322, thereby changing the pressure of the two oil cavities formed in the cylinder 31, and thus realizing the movement of the push plate 312. Since one end of the push plate 312 abuts against the bushing 23, and the bushing 23 is keyed to the main shaft 2, the first impeller 21 is fixedly connected to the bushing 23, and finally the first impeller 21 and the bushing 23 are moved. The impellers slide synchronously between the first impeller 21 and the second impeller 22, bringing them closer to the second impeller 22. At this time, the volume of the fluid boosting chamber 211 formed between the first impeller 21 and the second impeller 22 becomes smaller. The pumping volume can be controlled by controlling the rotational speed of the main shaft 2. In addition, since the blades between the first impeller 21 and the second impeller 22 are staggered, they can be retracted or extended towards each other. The contact area between them and the fluid varies depending on their relative positions. When they retract towards each other, the contact area between them and the fluid decreases, which can change the pumping volume and pumping pressure. Similarly, when the first impeller 21 needs to move away from the second impeller 22, the direction is opposite to the above principle.

[0088] The sliding between the bushing 23 and the main shaft 2 replaces the direct sliding between the existing bearing and the main shaft 2. Since the first impeller 21 is directly fixed on the bushing 23, it is exempt from the axial thrust generated during rotation. At the same time, the key connection between the bushing 23 and the main shaft 2 allows the impeller to move indirectly on the main shaft 2 through the bushing 23, while ensuring synchronous rotation with the main shaft. This avoids direct friction between the bearing acting on the impeller and the main shaft 2, and avoids lateral movement caused by bearing wear that would affect the variable control of the pump body. In addition, since the impeller propulsion mechanism 3 can precisely control the movement of the first impeller 21, it can improve the precision control of the pumped fluid volume.

[0089] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0090] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A novel variable displacement pump without thrust bearing, characterized in that, include: The pump casing (1) has a fluid inlet (11) and a fluid outlet (12) formed at opposite ends; A main shaft (2) is rotatably connected inside the pump casing (1), and a first impeller (21) is fixedly mounted on it; a bushing (23) is keyed to the main shaft (2), and a second impeller (22) is fixedly mounted on the bushing (23). The second impeller (22) and the first impeller (21) are staggered to form a fluid boosting chamber (211), and the fluid boosting chamber (211) is connected to the fluid input end (11) and the fluid output end (12). The impeller propulsion mechanism (3) is used to push the bushing (23) to slide on the main shaft (2) to control the volume change of the fluid pressurization chamber (211).

2. The novel variable pump without thrust bearing according to claim 1, characterized in that: The pump housing (1) has a first cavity (13) communicating with the fluid input end (11) and a second cavity (14) communicating with the fluid output end (12); the first cavity (13) and the second cavity (14) are respectively connected to the fluid boosting chamber (211).

3. A novel variable displacement pump without thrust bearing according to claim 2, characterized in that: An mounting sleeve (24) is fixedly provided on the pump casing (1), and a vertical plate (25) is fixedly provided at the bottom of the mounting sleeve (24); the main shaft (2) is rotatably connected inside the mounting sleeve (24), and an installation space (26) for the impeller propulsion mechanism (3) is formed between the mounting sleeve (24) and the main shaft (2).

4. A novel variable displacement pump without thrust bearing according to claim 1, characterized in that, The impeller propulsion mechanism (3) includes: The hydraulic cylinder (31) is installed in the installation space (26) and rotates synchronously with the main shaft (2). Its fixed end is fixedly connected to the main shaft (2), and its output end abuts against one end of the bushing (23). An oil supply pipe (32) is located inside the main shaft (2) and is used to supply oil to the oil cylinder (31); A hydraulic control system is used for metered oil supply or return to the cylinder (31).

5. A novel variable displacement pump without thrust bearing according to claim 4, characterized in that: The hydraulic cylinder (31) includes a fixed ring (311) fixedly connected to the main shaft (1) and a pusher plate (312) slidably sleeved on the fixed ring (311). The pusher plate (312) is rotatably connected to the mounting sleeve (24). A left oil chamber (314) and a right oil chamber (315) are formed between the fixed ring (311) and the pusher plate (312) through a partition plate (313). Both the left oil chamber (314) and the right oil chamber (315) are connected to the oil supply pipe (32). A wool felt (318) is provided between the fixed ring (311) and the mounting sleeve (24). The wool felt (318) is used for sealing the rotation between the mounting sleeve (24) and the pusher plate (312).

6. A novel variable displacement pump without thrust bearing according to claim 5, characterized in that: The oil supply pipe (32) includes a left cavity oil inlet pipe (321) and a right cavity oil inlet pipe (322) located in the main shaft (2). One end of the left cavity oil inlet pipe (321) is connected to the left oil cavity (314), and the other end is connected to a rotary joint (323). The rotary joint (323) is fixedly connected to the mounting sleeve (24). One end of the right cavity oil inlet pipe (322) is connected to the right oil cavity (315), and the other end is connected to the rotary joint (323).

7. A novel variable displacement pump without thrust bearing according to claim 6, characterized in that: A leakage groove (316) is formed between the fixed ring (311) and the mounting sleeve (24), and the leakage groove (316) is used to collect the hydraulic oil leaking from the cylinder (31); a return pipe (319) is formed inside the main shaft (2), one end of which is a closed end and the other end is connected to the rotary joint (323). One end of the return pipe (319) is connected to the right oil chamber (315) to collect the hydraulic oil leaking from the cylinder (31). A return hole (317) is opened on the main shaft (2), one end of which is connected to the return pipe (319) and the other end extends through to the push plate (312).

8. A novel variable displacement pump without thrust bearing according to claim 5, characterized in that: The hydraulic control system includes an oil supply component connected to the end of the rotary joint (323) away from the main shaft (2), pressure sensors disposed in the left and right oil chambers, and a linear displacement sensor located on the partition plate to detect the axial displacement of the propulsion plate relative to the fixed ring. The oil supply component is used for the alternating oil supply or return of the left oil chamber (314) and the right oil chamber (315).

9. A novel variable displacement pump control method without thrust bearing, using any of the aforementioned novel variable displacement pumps without thrust bearing, comprising the following steps: a) The hydraulic pressure is monitored in real time by pressure sensors installed in the left oil chamber (314) and right oil chamber (315), the axial position of the plate relative to the fixed ring (311) is monitored by a linear displacement sensor installed in the push plate (312), and the pumping volume is monitored by a flow sensor at the fluid output end (12). b) Using the Model Predictive Control (MPC) algorithm, a dynamic model is established based on the fluid dynamics of the fluid booster chamber (211), the hydraulic oil flow and the propeller plate mechanics. The propeller plate position and pumping volume are predicted within 0.1-1 seconds. The oil supply flow rate of the proportional control valve of the oil supply component is optimized, and the propeller plate (312) is moved to adjust the volume of the fluid booster chamber (211). c) The controller processes the sensor data and generates a control signal for the proportional control valve of the oil supply component, thereby realizing the alternating oil supply or return of the left oil chamber (314) and the right oil chamber (315); d) Monitor hydraulic oil leakage through flow sensors in the leakage groove (316) and return pipe (319) and dynamically adjust the oil supply to compensate for the loss; The controller is a programmable logic controller (PLC) or a microcontroller, running on a real-time operating system.

10. The control method according to claim 9, characterized in that, It also includes security and stability mechanisms, including the following steps: a) Set the maximum pressure threshold for the left oil chamber (314) and the right oil chamber (315) to prevent overpressure damage to the propeller plate or spindle; b) Vibration is monitored by the accelerometer on the mounting sleeve (24), and a safety shutdown is triggered when the threshold is exceeded; c) In case of abnormal conditions, enter safety mode, stop the propulsion plate movement and maintain neutral pressure in the oil chamber.

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