Hydraulic servo system for dynamic force loading test of main shaft of marine diesel engine

Abstract

The utility model belongs to the field of marine diesel engines, particularly relates to a dynamic force loading test hydraulic servo system for a main shaft of a marine diesel engine, and aims to solve the problems that the main shaft rotates at a high speed, the axial movement frequency is high, the axial movement force is large, and the service life is short in the operation process of the conventional marine diesel engine. In order to solve the problem that dynamic force loading on a rotating high-frequency moving main shaft has certain technical difficulty, the utility model provides the following scheme: the diesel engine main shaft dynamic force loading device comprises a diesel engine main shaft main body and an oil cylinder, the diesel engine main shaft main body is positioned at one end of the oil cylinder, and the same group of test components for testing are arranged between the diesel engine main shaft main body and the oil cylinder; according to the utility model, the electro-hydraulic servo control system is introduced, the system has the outstanding advantages of high response speed, large output power, high control accuracy and the like, and the spring assembly is selected as an intermediate transmission link of loading, so that the influence of high-frequency axial movement of the diesel engine main shaft on the loading servo oil cylinder can be effectively reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of marine diesel engines, in particular to a hydraulic servo system for dynamic force loading testing of a main shaft of a marine diesel engine. Background Art

[0002] Marine diesel engines are used on ships. During navigation, they are subject to the forces of water, causing pitch and roll. The diesel engine's main shaft is a solid crankshaft with considerable mass. This weight exerts random axial forces on the engine during pitch and roll. Therefore, during land-based diesel engine experiments, dynamic axial force loading is required to simulate the engine's operating state during navigation and to collect critical experimental data.

[0003] However, during the operation of a marine diesel engine, the main shaft rotates at high speed, and the axial vibration frequency is high, resulting in a large axial vibration force. Therefore, it is technically difficult to dynamically load the rotating high-frequency vibration main shaft, and there is currently no standard test solution on the market. Utility Model Content

[0004] The purpose of the utility model is to solve the shortcomings in the prior art that, during the operation of a marine diesel engine, the main shaft rotates at high speed, the axial movement frequency is high, and the axial movement force is large, so it is technically difficult to dynamically load the rotating high-frequency moving main shaft. A hydraulic servo system for dynamic force loading test of a marine diesel engine main shaft is proposed.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A hydraulic servo system for dynamic force loading testing of a marine diesel engine main shaft comprises a diesel engine main shaft body and an oil cylinder, wherein the diesel engine main shaft body is located at one end of the oil cylinder, and a same set of test components for testing is arranged between the diesel engine main shaft body and the oil cylinder;

[0007] A servo valve is provided on one side of the oil cylinder, and the servo valve is used to control the extension and contraction of the oil cylinder. An oil tank is provided on one side of the oil cylinder, and a gear pump is provided on one side of the oil tank. A motor is provided on one side of the gear pump, and the motor is used to provide power to the gear pump.

[0008] An oil supply assembly for supplying oil to the oil cylinder is provided between the gear pump and the servo valve.

[0009] In one possible design, the test assembly includes a rectangular plate fixedly connected to one end of the cylinder piston rod, a rotating loading disk is provided at one end of the diesel engine main shaft body, a tension sensor is provided at one end of the rotating loading disk, a same spring is fixedly connected between the rectangular plate and the tension sensor, a thrust bearing is provided inside the tension sensor, and a displacement sensor is provided at the end of the cylinder away from the rectangular plate.

[0010] In one possible design, the oil supply assembly includes a high-pressure filter connected to one side of the gear pump through a pipeline, one side of the oil tank is connected to a return oil filter through a pipeline, one side of the return oil filter is connected to a fresh water cooler through a pipeline, and the fresh water cooler and the high-pressure filter are connected to the two oil holes of the oil cylinder through pipelines.

[0011] In a possible design, an air filter is provided on one side of the top of the fuel tank, a liquid level and temperature gauge is provided in the middle of the top of the fuel tank, and a liquid level gauge is provided on one side of the fuel tank.

[0012] In a possible design, a one-way valve is provided on the pipeline between the high-pressure filter and the gear pump, and a pressure gauge and an accumulator are provided on the pipeline between the high-pressure filter and the oil cylinder.

[0013] In a possible design, pressure sensors and solenoid valves are provided on the pipelines between the fresh water cooler, the high-pressure filter and the oil cylinder.

[0014] In this application, the hydraulic system uses a motor to drive a gear pump to power the entire loading control device. High-pressure oil at the pump outlet passes through a high-pressure filter before reaching a servo valve. The servo valve controls the oil flow rate to control the extension and extension of the servo cylinder, thereby controlling the compression of the spring.

[0015] The high-pressure filter can ensure the cleanliness of the oil entering the servo valve to avoid servo valve blockage caused by oil contamination, thereby improving system reliability. At the same time, the high-pressure filter is equipped with a filter blockage alarm, which can remind the operator to replace the filter element when the filter is blocked to maintain the normal operation of the system.

[0016] An overflow valve is installed on the bypass circuit to serve as a safety valve to ensure that the system pressure is maintained within a safe range.

[0017] The pump station accumulator is installed at the high-pressure oil port to replenish oil and absorb hydraulic shock. The hydraulic system uses a fresh water cooler as a system heat dissipation device to ensure the normal operating oil temperature of the system.

[0018] The entire device adopts an electro-hydraulic servo control system for curve loading control. The electro-hydraulic servo system has outstanding advantages such as fast response speed, large output power and high control accuracy.

[0019] First, the host computer converts the force curve required by the loading system into the displacement of the spring assembly, which is the target displacement of the piston rod of the servo cylinder. It also calculates the current control signal and sends it to the servo valve coil to drive the electro-hydraulic servo valve core to move. The hydraulic source provides power to drive the hydraulic cylinder to realize the loading function. The actual displacement of the piston rod is fed back to the host computer and the hydraulic servo controller through the displacement sensor. By comparing the error between the given command signal and the feedback signal, a displacement closed-loop control system is formed after appropriate PID control calculation. The feedback signal is compared with the input signal to obtain a deviation signal, which makes the system change in the direction of reducing the deviation. The signal sent to the servo valve is continuously corrected until the deviation is equal to zero or small enough, so that the actual output of the system matches the expected value until the index requirements are met, thus realizing the closed-loop control function.

[0020] The loading device primarily utilizes a servo cylinder to apply force to the diesel engine's main shaft. First, the cylinder's piston rod applies force to a spring assembly, which transmits this force to a tension sensor. The tension sensor then applies force to a thrust bearing. This bearing isolates the diesel engine's main shaft from rotation and transmits the force on the outer ring to the inner ring, which in turn transmits this force to a rotating loading plate, ultimately applying force to the rotating diesel engine's main shaft.

[0021] The use of a spring assembly effectively reduces the impact of high-frequency axial motion of the diesel engine main shaft on the loading servo cylinder. Furthermore, according to Hooke's law, spring force F = kX (k represents the spring stiffness). When dynamically loading the diesel engine main shaft, the applied force curve can be converted into spring compression, which translates to the displacement curve of the servo cylinder piston. This conversion of force loading, which is directly affected by main shaft motion, into displacement loading for the servo cylinder provides more reliable and convenient control.

[0022] Beneficial Effects: Improved loading accuracy and stability: By introducing an electro-hydraulic servo control system, the system boasts fast response, high output power, and precise control. Furthermore, closed-loop control using a displacement sensor allows for real-time correction of the signal sent to the servo valve, ensuring that the system's actual output matches the desired value, thereby improving loading accuracy and stability.

[0023] Effectively reduces the impact of high-frequency axial movement: Using a spring assembly as the intermediate transmission link for loading can effectively reduce the impact of high-frequency axial movement of the diesel engine main shaft on the loading servo cylinder. This design allows the loading force to be applied to the main shaft more stably, improving the accuracy and reliability of the test.

[0024] Improve oil cleanliness and system reliability: Filtering the oil entering the servo valve through a high-pressure filter ensures oil cleanliness and prevents servo valve blockage caused by oil contamination. The high-pressure filter also features a filter blockage alarm, reminding operators to replace the filter element promptly to maintain normal system operation.

[0025] Ensure system safety: An overflow valve is installed on the bypass circuit as a safety valve to ensure that the system pressure is maintained within a safe range, avoiding system damage or safety accidents caused by excessive pressure.

[0026] Optimize system heat dissipation: Using a fresh water cooler as the system heat dissipation device can ensure the normal operating oil temperature of the system and avoid system performance degradation or failure due to excessively high oil temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the main structure of a hydraulic servo system for dynamic force loading test of a main shaft of a marine diesel engine proposed by the present invention;

[0028] Figure 2 This is a hydraulic principle diagram of a hydraulic servo system for dynamic force loading test of a marine diesel engine main shaft proposed by the utility model.

[0029] In the figure: 1. Diesel engine main shaft body; 2. Rotating loading plate; 3. Spring; 4. Cylinder; 5. Displacement sensor; 6. Servo valve; 7. Rectangular plate; 8. Tension sensor; 9. Thrust bearing; 10. Accumulator; 11. Pressure gauge; 12. High-pressure filter; 13. Check valve; 14. Motor; 15. Air filter; 16. Gear pump; 17. Liquid level and temperature gauge; 18. Fuel tank; 19. Liquid level gauge; 20. Return oil filter; 21. Fresh water cooler; 22. Solenoid valve; 23. Pressure sensor. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0031] Example 1; Reference Figure 1-2 A hydraulic servo system for dynamic force loading test of a marine diesel engine main shaft is used in the field of marine diesel engines. It includes: a diesel engine main shaft body 1 and a cylinder 4. The diesel engine main shaft body 1 is located at one end of the cylinder 4. A same set of test components for testing is arranged between the diesel engine main shaft body 1 and the cylinder 4.

[0032] A servo valve 6 is provided on one side of the oil cylinder 4, and the servo valve 6 is used to control the extension and contraction amount of the oil cylinder 4. An oil tank 18 is provided on one side of the oil cylinder 4, and a gear pump 16 is provided on one side of the oil tank 18. A motor 14 is provided on one side of the gear pump 16, and the motor 14 is used to provide power to the gear pump 16. The hydraulic system uses the motor 14 to drive the gear pump 16 to provide power for the entire loading control device. After passing through high-pressure filter 12, high-pressure oil at the pump outlet reaches servo valve 6. Servo valve 6 controls the oil flow rate to control the expansion and contraction displacement of servo cylinder 4, thereby controlling the compression of spring 3. The test assembly includes a rectangular plate 7 fixedly connected to one end of the piston rod of cylinder 4. A rotating loading plate 2 is installed at one end of the diesel engine main shaft body 1, and a tension sensor 8 is installed at one end of the rotating loading plate 2. A spring 3 is fixedly connected between rectangular plate 7 and tension sensor 8. A thrust bearing 9 is installed inside tension sensor 8. A displacement sensor 5 is installed at the end of cylinder 4 away from rectangular plate 7. First, the host computer converts the force curve required by the loading system into the displacement of the spring 3 assembly, which is the target displacement of the piston rod of servo cylinder 4. The current control signal is calculated and sent to the coil of servo valve 6, driving the valve core of electro-hydraulic servo valve 6 to move. The hydraulic source provides power, driving the hydraulic cylinder to realize the loading function. The actual displacement of the piston rod is fed back to the host computer and hydraulic servo controller through displacement sensor 5. By comparing the error between the given command signal and the feedback signal and performing appropriate PID control operations, a displacement closed-loop control system is formed. The feedback signal is compared with the input signal to obtain a deviation signal, so that the system changes in the direction of reducing the deviation, and the signal transmitted to the servo valve 6 is continuously corrected until the deviation is equal to zero or small enough, so that the actual output of the system is consistent with the expected value until the index requirements are met. In this way, the closed-loop control function is realized. In the main composition of the loading device, the system applies force to the diesel engine main shaft body 1 through the servo cylinder 4. First, the piston rod of the oil cylinder 4 applies a force to the spring 3 assembly, which transmits the force to the tension sensor 8. The tension sensor 8 applies the force to the thrust bearing 9. The bearing can isolate the rotation of the diesel engine main shaft body 1 and transmit the force on the outer ring to the inner ring, and then transmit the force to the rotating loading plate 2, and finally apply a force to the rotating diesel engine main shaft body 1. The use of the spring 3 assembly can effectively reduce the impact of the high-frequency axial movement of the diesel engine main shaft body 1 on the loading servo oil cylinder 4. At the same time, according to Hooke's law, the spring 3 force F=kXk is the spring 3 stiffness. When the diesel engine main shaft body 1 is dynamically loaded with force, the force curve can be converted into the spring 3 compression, that is, the displacement curve of the piston of the loading servo oil cylinder 4. Converting the force loading that is easily affected by the main shaft movement into the displacement loading of the servo oil cylinder 4 makes the control more reliable and convenient.

[0033] An oil supply assembly for supplying oil to the cylinder 4 is provided between the gear pump 16 and the servo valve 6. The oil supply assembly includes a high-pressure filter 12 connected to one side of the gear pump 16 through a pipeline. The high-pressure filter 12 can ensure the cleanliness of the oil entering the servo valve 6 to avoid clogging of the servo valve 6 caused by oil contamination, thereby improving system reliability. At the same time, the high-pressure filter 12 is provided with a filter clogging alarm, which can remind the operator to replace the filter element to maintain the normal operation of the system when the filter is clogged. A return oil filter 20 is connected to one side of the oil tank 18 through a pipeline, and a fresh water cooler 21 is connected to one side of the return oil filter 20 through a pipeline. The fresh water cooler 21 and the high-pressure filter 12 are connected to the two oil holes of the cylinder 4 through pipelines. An air filter 15 is provided on one side of the top of the oil tank 18, a liquid level and temperature gauge 17 is provided in the middle position of the top of the oil tank 18, and a liquid level gauge 19 is provided on one side of the oil tank 18.

[0034] Example 2; Reference Figure 1-2 , improved on the basis of Example 1: a one-way valve 13 is provided on the pipeline between the high-pressure filter 12 and the gear pump 16, a pressure gauge 11 and an accumulator 10 are provided on the pipeline between the high-pressure filter 12 and the oil cylinder 4, and a pressure sensor 23 and a solenoid valve 22 are provided on the fresh water cooler 21 and the pipeline between the high-pressure filter 12 and the oil cylinder 4.

[0035] However, as is well known to those skilled in the art, the working principles and wiring methods of the high-pressure filter 12, the oil cylinder 4, the pressure sensor 23 and the solenoid valve 22, the pressure gauge 11 and the accumulator 10, the fresh water cooler 21, and the high-pressure filter 12 are commonplace and are conventional means or common knowledge, and will not be elaborated herein. Those skilled in the art may make any selections according to their needs or convenience.

[0036] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A hydraulic servo system for dynamic force loading test of a marine diesel engine main shaft, characterized in that: include: A diesel engine main shaft body (1) and an oil cylinder (4), wherein the diesel engine main shaft body (1) is located at one end of the oil cylinder (4), and a same set of test components for testing is provided between the diesel engine main shaft body (1) and the oil cylinder (4), wherein the test component comprises a rectangular plate (7) fixedly connected to one end of a piston rod of the oil cylinder (4), a rotating loading disk (2) is provided at one end of the diesel engine main shaft body (1), a tension sensor (8) is provided at one end of the rotating loading disk (2), a same spring (3) is fixedly connected between the rectangular plate (7) and the tension sensor (8), a thrust bearing (9) is provided inside the tension sensor (8), and a displacement sensor (5) is provided at one end of the oil cylinder (4) away from the rectangular plate (7); A servo valve (6) is provided on one side of the oil cylinder (4), and the servo valve (6) is used to control the extension and contraction amount of the oil cylinder (4). An oil tank (18) is provided on one side of the oil cylinder (4), and a gear pump (16) is provided on one side of the oil tank (18). A motor (14) is provided on one side of the gear pump (16), and the motor (14) is used to provide power to the gear pump (16); An oil supply assembly for supplying oil to the oil cylinder (4) is provided between the gear pump (16) and the servo valve (6).

2. A hydraulic servo system for dynamic force loading test of a main shaft of a marine diesel engine according to claim 1, characterized in that: The oil supply assembly comprises a high-pressure filter (12) connected to one side of a gear pump (16) via a pipeline, a return oil filter (20) is connected to one side of the oil tank (18) via a pipeline, a fresh water cooler (21) is connected to one side of the return oil filter (20) via a pipeline, and the fresh water cooler (21) and the high-pressure filter (12) are connected to two oil holes of the oil cylinder (4) via pipelines.

3. A hydraulic servo system for dynamic force loading test of a main shaft of a marine diesel engine according to claim 1, characterized in that: An air filter (15) is provided on one side of the top of the oil tank (18), a liquid level and temperature gauge (17) is provided at the middle position of the top of the oil tank (18), and a liquid level gauge (19) is provided on one side of the oil tank (18).

4. A hydraulic servo system for dynamic force loading test of a main shaft of a marine diesel engine according to claim 2, characterized in that: A one-way valve (13) is provided on the pipeline between the high-pressure filter (12) and the gear pump (16), and a pressure gauge (11) and an accumulator (10) are provided on the pipeline between the high-pressure filter (12) and the oil cylinder (4).

5. A hydraulic servo system for dynamic force loading test of a main shaft of a marine diesel engine according to claim 2, characterized in that: A pressure sensor (23) and a solenoid valve (22) are provided on the pipelines between the fresh water cooler (21), the high-pressure filter (12) and the oil cylinder (4).

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