Boat Drive Control Device Backlash Elimination
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Solution Overview
Problem
Existing boat drive control devices experience play or backlash in gear transmission, leading to unstable rudder or steering position and indirect control feedback for the helmsman, affecting the accuracy and directness of steering.
Innovation Solution
A control device with two counteracting servomotors driving a multi-stage reduction gear system, including planetary gears, which eliminates backlash by clamping the gear between them, providing a stable propeller thrust vector and direct steering feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single servomotor with gear transmission is used to control the propulsion unit, then the device complexity is reduced, but backlash occurs in the gear leading to unstable steering position
Solution Approach 1:
The control device is segmented into two independent servomotors (first and second) that separately drive the propulsion unit through gear transmissions. This segmentation allows each motor to independently control one side of the propulsion unit, eliminating backlash by preventing the gear teeth from engaging with play while maintaining relatively simple individual motor structures.
2Reliability
If two counteracting servomotors are used to eliminate backlash, then steering position stability is improved, but the device complexity increases
Solution Approach 1:
Each servomotor is designed with locally optimized gear transmission characteristics - the first servomotor drives one side of the propulsion unit while the second servomotor drives the other side. This local quality approach allows each motor-gear assembly to be independently tuned to eliminate backlash at its specific location, achieving overall system stability without requiring a completely complex unified structure.
3Measurement precision
If a multi-stage reduction gear is used, then the control precision is improved, but the device complexity and installation space requirements increase
Solution Approach 1:
The gear transmission systems of the two servomotors are nested or closely integrated in the control device structure. The first and second gear transmissions are arranged to share space efficiently, with their respective gear stages nested or positioned adjacently. This nesting approach achieves the required multi-stage reduction for high precision control while minimizing the overall installation space of the control device.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves a stable rudder position and direct steering control, ensuring the boat runs accurately on course, with the helmsman experiencing direct translation of steering wheel movements into boat steering.
Implementation Method 1
the drive-side gear is simultaneously driven by two servomotors that work slightly counter to each other. This has the advantage of eliminating backlash in the gear, particularly flank backlash. The two servomotors working against each other prevent any flank backlash in the jointly driven gear, essentially clamping it between them.
Implementation Method 2
the speed of each of the two servomotors or electric motors is reduced in a first stage by a first planetary gear, with the output of each of the two first planetary gears being provided via a drive pinion
Implementation Method 3
a second planetary gear is provided, coaxial with the pivot axis of the propulsion unit. The second planetary gear functions as a second reduction stage and is driven via its planetary carrier by the two drive pinions of the first two planetary gears
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a control device, especially for a boat drive, comprising an operating mechanism, a reduction gear (8, 11, 15/17) and an actuator (2) that can be moved at a control angle. According to the invention, the reduction gear comprises a multi-stage gear mechanism (8, 11, 15/17) provided with a toothed gear (10) on the drive side, and the operating mechanism comprises two servomotors (6) driving the toothed wheel simultaneously but in a slightly counter-rotating manner.