Belt type double-angle encoder transmission device for transmitting angle signal of crankshaft of marine low-speed engine and marine low-speed engine

Abstract

The invention discloses a belt type marine angle encoder transmission device, and belongs to the technical field of marine low-speed engine manufacturing. The device comprises a transmission shaft, a heavy-load flexible coupling, a gear belt mechanism and a double-angle encoder which are connected in sequence. The transmission shaft input end is connected with an engine crankshaft through a flange; the heavy-load coupling is used for absorbing axial vibration of the crankshaft; the gear belt mechanism synchronously transmits motion to the two angle encoders through a synchronous belt, and double-path redundancy collection of crank angle signals is achieved. Vibration interference is effectively restrained through the flexible coupling, synchronous precision is guaranteed through belt transmission, system reliability is improved through double-encoder redundancy design, the technical problems that in a traditional scheme, signals are prone to distortion, and safety redundancy is lacked are solved, and accuracy and safety of engine fuel injection and exhaust valve timing control are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of marine low-speed engine manufacturing technology, specifically to a belt-type dual-angle encoder transmission device for transmitting crankshaft angle signals in marine low-speed engines, which is particularly suitable for realizing synchronous transmission between the crankshaft and the dual-angle encoder. Background Technology

[0002] As the core power unit of large ships, marine low-speed engines directly affect the overall operational efficiency of the vessel due to their operational reliability, economy, and emissions performance. With increasingly stringent emission regulations from the International Maritime Organization (IMO) and the development of intelligent and green ships, key subsystems of modern marine low-speed engines, such as fuel injection systems and exhaust valve control systems, have achieved full electronic and high-precision closed-loop control. Against this backdrop, the engine control system faces unprecedentedly high demands on the accuracy, real-time performance, and reliability of crankshaft angle signals.

[0003] The crankshaft angle signal is the core basis for calculating engine speed, determining the piston top dead center (TDC) position, and precisely controlling fuel injection timing and exhaust valve opening and closing times. Any deviation or interruption of the signal may lead to inaccurate fuel injection strategy, resulting in poor engine combustion, reduced power, excessive emissions, and in severe cases, even engine malfunction.

[0004] Currently, most marine low-speed engines employ a single-path crankshaft signal transmission scheme, typically driving a single-angle encoder via gears or rigid couplings. This traditional approach suffers from the following technical limitations:

[0005] Poor vibration resistance: During engine operation, the crankshaft experiences significant axial and torsional vibrations. Rigid transmission methods can easily transmit these vibrations directly to the encoder, leading to signal acquisition distortion, shortened encoder lifespan, or even damage.

[0006] Lack of redundancy safety: A single angle encoder constitutes a single point of failure. Once a failure occurs, the engine control system will lose critical crankshaft position information, forcing the engine to operate at a reduced speed or shut down, posing a significant risk to navigation safety.

[0007] Insufficient synchronization accuracy and reliability: Traditional gear drives are prone to wear and backlash after long-term operation, leading to the accumulation of transmission errors and affecting the synchronization accuracy between the crankshaft and the encoder; although belt drives have the advantage of vibration absorption, there is insufficient design and application experience under high torque and heavy load conditions, and there is a lack of mature engineering applications under dual encoder redundancy architecture.

[0008] Therefore, there is an urgent need to develop a new type of transmission device that can simultaneously solve the three technical challenges of high-precision synchronous transmission, effective vibration compensation, and redundant safety design, so as to meet the stringent requirements of the new generation of intelligent low-speed diesel engines for control accuracy, operational reliability, and safety. Summary of the Invention

[0009] The present invention aims to solve the technical problems existing in the existing crankshaft angle signal transmission scheme of marine low-speed engines, and provides a belt-type dual-angle encoder transmission device for transmitting crankshaft angle signals of marine low-speed engines.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A belt-type dual-angle encoder transmission device for transmitting crankshaft angle signals in marine low-speed engines, characterized in that it includes:

[0012] The drive shaft has its input end rigidly connected to the crankshaft end of the marine low-speed engine via a flange connector to synchronously transmit the rotational motion of the crankshaft.

[0013] A heavy-duty flexible coupling, the input end of which is coaxially connected to the output end of the drive shaft, is used to absorb and compensate for the axial and torsional vibrations generated during the operation of the crankshaft;

[0014] The gear belt mechanism has its input shaft coaxially and fixedly connected to the output end of the heavy-duty flexible coupling;

[0015] Two angle encoders are provided, and the two output ends of the gear belt mechanism are respectively connected to the input shafts of the two angle encoders to transmit the rotational motion after vibration compensation by the heavy-duty flexible coupling to the two angle encoders synchronously, so as to realize dual-channel redundant signal acquisition.

[0016] Furthermore, the gear and belt mechanism includes:

[0017] A belt drive shaft is fixedly mounted on the input shaft of the gear belt mechanism;

[0018] Two belt gears are respectively fixedly mounted on the input shafts of the two angle encoders and are located on the same axis as the belt drive shaft;

[0019] Two synchronous belts are respectively tensioned and meshed between the belt drive shaft and one of the belt gears, forming two independent power transmission paths.

[0020] Furthermore, it also includes a fixed bracket and a coupling observation window;

[0021] The fixed bracket is used to mount the entire transmission device onto the cover at the free end of the engine.

[0022] The observation window of the coupling is fixed to the cover by bolts, and its observation port is directly facing the setting position of the heavy-duty flexible coupling, so as to visually monitor the operating status of the coupling.

[0023] The present invention also provides a marine low-speed engine, including a crankshaft, a housing, and an engine control system, characterized in that it further includes a belt-type marine angle encoder transmission device as described above; the transmission device is mounted on the free end of the housing via the fixed bracket; the signal output terminals of the two angle encoders are electrically connected to the engine control system to provide two redundant crankshaft angle position signals to the control system.

[0024] The present invention also provides a method for crankshaft signal processing and control using the above-mentioned transmission device, characterized by comprising the following steps:

[0025] The crankshaft angle signal is acquired in real time and independently using two angle encoders.

[0026] The two angle signals are transmitted to the engine control system.

[0027] The engine control system performs real-time cross-verification and logical judgment on the two signals;

[0028] The engine control system accurately calculates and controls fuel injection timing and exhaust valve opening and closing timing based on a verified reliable crankshaft angle signal.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1) A heavy-duty flexible coupling was introduced as a primary vibration damping unit to absorb the severe axial and torsional vibrations of the crankshaft, preventing the vibration from being directly transmitted to the precision encoder, solving the signal distortion problem, improving the lifespan of the encoder, and ensuring the original accuracy of the angle signal acquisition.

[0031] 2) A redundant architecture with dual-angle encoders and independent dual-belt drive paths is adopted, which eliminates the risk of single-point failure. When one encoder or drive path fails, the engine control system can still maintain the key control functions of the engine based on the other normal signal, which greatly improves the safety and operational continuity of the ship's power system and meets the stringent requirements of modern intelligent ships for the reliability of the power system.

[0032] 3) Using synchronous belt drive as the final drive method can further smooth the transmission process. Compared with traditional gear drive, it avoids the long-term accuracy decay caused by gear wear and backlash, and ensures long-term, stable, and high-precision synchronization between the crankshaft and the dual encoders.

[0033] 4) By setting up an observation window for the coupling, the operating status of key components can be monitored without disassembly, which facilitates daily maintenance and fault early warning, and improves the practicality and maintainability of the device. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the installation of the belt-type marine angle encoder transmission device of the present invention on a marine engine.

[0035] Figure 2 This is an exploded view of the present invention;

[0036] Figure 3 This is a front view of the present invention.

[0037] Figure 4 This is the isometry diagram of the present invention.

[0038] In the diagram: 1-crankshaft drive shaft 1, 2-heavy-duty flexible coupling, 3-angle encoder;

[0039] 4-Coupling drive gear, 7-Intermediate drive shaft, 41-Belt drive shaft, 42-Belt gear, 43-Synchronous belt, 5-Coupling observation window, 6-Fixed bracket. Detailed Implementation

[0040] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. This embodiment is implemented based on the technical solution of the present invention, and provides detailed installation steps, transmission chain connection relationships, and functional implementation processes of each component. However, the scope of protection of the present invention is not limited to the following embodiment.

[0041] 1. Installation and mechanical connection

[0042] like Figure 1 As shown, the overall base of this transmission device is rigidly mounted on the housing at the free end of the marine low-speed engine by bolts. This mounting position has the advantages of ample space and easy access for maintenance.

[0043] like Figure 2 As shown in the exploded view, the core transmission link of this device consists of the following components connected in sequence:

[0044] Crankshaft drive shaft 1: One end of the crankshaft drive shaft is centered and connected to the output end of the engine crankshaft through a flange coupling, thus serving as the input shaft of the entire transmission chain, replicating the rotational motion of the crankshaft, and acting as a power input source.

[0045] Heavy-duty flexible coupling 2: One end of this heavy-duty flexible coupling 2 is rigidly connected to the other end of the crankshaft drive shaft 1. It employs a metal disc spring and a rubber-metal composite structure, possessing high torque transmission capacity and axial, radial, and angular misalignment compensation functions. The other end is connected to the coupling drive gear 4 via a flexible coupling structure, used to isolate and absorb the severe axial vibration and partial torsional vibration generated by the engine crankshaft during operation, preventing vibration energy from being transmitted to the subsequent precision encoder transmission mechanism.

[0046] Coupling observation window 5: To facilitate daily inspection and condition monitoring, a coupling observation window 5 is provided on the engine free end cover, directly opposite the heavy-duty coupling 2. This window is made of transparent high-strength polycarbonate material and is sealed and fixed by tightening the sealing ring with surrounding bolts. This allows operators to visually inspect the operation of the heavy-duty coupling 2 and whether there is any abnormal wear without disassembling the cover.

[0047] Coupling transmission gear 4: One end is flexibly connected to heavy-duty coupling 2, and the other end is linked to angle encoder belt transmission shaft 41 through intermediate transmission shaft 7.

[0048] Angle encoder housing mounting bracket 6: Fixed to the mechanical system housing, supporting and fixing the angle encoder housing.

[0049] The two angle encoders 3 are linked by belt 43 and belt gear 42 to achieve mutual redundancy.

[0050] Belt gear 42: Located at both ends of the belt, it meshes with the coupling transmission gear, the intermediate transmission shaft, and the belt transmission shaft respectively to realize power transmission.

[0051] Through append Figure 2 The crankshaft drive shaft connects the present invention to the engine crankshaft; the heavy-duty coupling absorbs and compensates for the vibration energy of the engine crankshaft during operation, while driving the load at the rear end. To protect the heavy-duty coupling and observe its operating status, the present invention incorporates a coupling observation window, which is bolted to the engine free end cover.

[0052] Appendix Figure 2 The coupling drive gear and angle encoder drive shaft are responsible for connecting the heavy-duty coupling to the belt gear. The housing mounting bracket holds the angle encoder coupling's observation window to the housing. Thus, the belt gear completes the connection to the engine crankshaft.

[0053] Appendix Figure 2 The two belts in the crankshaft drive the rotation of two angle encoders through gears, thus realizing the simultaneous synchronous rotation of the dual angle encoders with the crankshaft: that is, acquiring the crankshaft rotation angle signal and realizing the redundancy function based on safety factors.

[0054] When the engine crankshaft rotates, power is transmitted sequentially through drive shaft 1, heavy-duty flexible coupling 2, and intermediate drive shaft 7 to belt drive shaft 41. Subsequently, the input shafts of the two angle encoders 3 are driven to rotate through two synchronous belts 43 respectively. Due to the good elasticity and meshing accuracy of the synchronous belts, the backlash problem of traditional gear drives can be effectively avoided, ensuring strict synchronization between the encoders and the crankshaft.

[0055] The dual encoder design enables redundant signal acquisition. The engine control system receives two angle signals in real time and performs cross-checking and logical judgment. If one signal is abnormal, the system can automatically switch to the other signal or issue a fault alarm to ensure the continuity and accuracy of fuel injection and exhaust valve control.

[0056] The device was designed with ease of maintenance in mind: the coupling observation window 5 facilitates daily inspections; the synchronous belt 43 is made of oil-resistant and high-temperature resistant rubber material, which has a long service life and is easy to replace; the overall structure is compact and suitable for installation and commissioning in the limited space of the engine compartment.

[0057] This invention integrates and innovates "flexible coupling vibration reduction + synchronous belt drive + dual encoder redundancy" to form a complete, efficient and reliable crankshaft angle signal transmission solution, which effectively meets the multiple requirements of the new generation of marine low-speed engines for control accuracy, reliability and safety.

Claims

1. A belt type dual angle encoder drive for crankshaft angle signal transmission of a marine low speed engine, characterized in that, It comprises: a transmission shaft (1) with its input end rigidly connected to the crankshaft end of a marine low-speed engine through a flange connector, for synchronously transmitting the rotational motion of the crankshaft; a heavy-duty flexible coupling (2) with its input end coaxially connected to the output end of the transmission shaft (1), for absorbing and compensating the axial and torsional vibrations generated during the operation of the crankshaft; a gear belt mechanism (4) with its input shaft fixedly connected to the output end of the heavy-duty flexible coupling (2); two angle encoders (3) with the two output ends of the gear belt mechanism (43) respectively drivingly connected to the input shafts of the two angle encoders (3), for synchronously transmitting the rotational motion after vibration compensation by the heavy-duty flexible coupling (2) to the two angle encoders (3), realizing double-channel redundant signal acquisition.

2. Belted dual angle encoder drive according to claim 1, characterized in that: The gear belt mechanism comprises: a belt transmission shaft (41) fixedly sleeved on the input shaft of the gear belt mechanism; two belt gears (42) respectively fixedly sleeved on the input shafts of the two angle encoders (3) and located on the same axis as the belt transmission shaft (41); two synchronous belts (43) respectively tightly engaged between the belt transmission shaft (41) and one of the belt gears (42), forming two independent power transmission paths.

3. The belt dual angle encoder drive of claim 1, wherein: It further comprises a fixed bracket and a coupling observation window; The fixed bracket is used to mount the entire transmission device on the cover of the free end of the engine; The coupling observation window is sealed and fixed to the cover by bolts, and its observation port is directly opposite the installation position of the heavy-duty flexible coupling (2), for visual monitoring of the running state of the coupling.

4. A marine low speed engine comprising a crankshaft, a casing and an engine control system, characterized in that It further comprises the belt type marine angle encoder transmission device according to any one of claims 1 to 3; the transmission device is mounted on the free end of the cover through the fixed bracket; the signal output ends of the two angle encoders (3) are electrically connected to the engine control system, for providing two redundant crankshaft angle position signals to the control system.

5. A method for processing and controlling the crankshaft signal using the transmission device as claimed in claim 1, characterized in that, It comprises the following steps: Real-time and independent acquisition of the angle signals of the crankshaft by the two angle encoders (3); Transmission of the two angle signals to the engine control system; Real-time cross-checking and logical judgment of the two signals by the engine control system; Based on the reliable crankshaft angle signals after checking, the engine control system accurately calculates and controls the fuel injection timing and exhaust valve opening and closing timing.

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