Base Station Antenna Transmission Linkage for Precise Tilt Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing transmission devices for high-band wireless antennas in base station antennas face challenges in achieving precise remote electrical tilt adjustments due to manufacturing and assembly tolerances, necessitating improved precision in the adjustment mechanism.
Innovation Solution
A transmission device with a motor, screw, transmission shaft, and linkage system, incorporating a worm, worm gear, spur gears, and connecting rod engagement elements, featuring polygonal structures and restriction slots to minimize assembly tolerance, ensuring precise positioning of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional transmission devices are used for high-band wireless antennas, then the device complexity is reduced, but the adjustment precision deteriorates due to manufacturing and assembly tolerances
Solution Approach 1:
The patent applies preliminary action by pre-defining the zero position of the worm gear through a polygonal structure (e.g., decagonal) that engages with a corresponding polygonal portion on the transmission shaft. This preliminary positioning action compensates for assembly tolerances before the actual adjustment operation begins, ensuring that the phase shifter starts from an accurately defined reference position. The restriction slot and restriction element further reinforce this by pre-positioning the connecting rod engagement element in its zero position, eliminating the need for post-assembly calibration and achieving adjustment precision within ±0.5mm despite manufacturing variations.
2Reliability
If conventional transmission devices are used for high-band wireless antennas, then the ease of manufacture is improved, but the reliability of precise positioning deteriorates
Solution Approach 1:
The patent employs asymmetry through the use of polygonal structures (e.g., decagonal inner surface of the shaft bore and corresponding decagonal outer surface of the transmission shaft) instead of conventional circular interfaces. This asymmetric geometry provides unique engagement positions that define the zero position of the worm gear, preventing rotational ambiguity and ensuring reliable positioning. The restriction slot perpendicular to the movement direction of the connecting rod engagement element also utilizes asymmetric positioning to define the zero position. These asymmetric features, while requiring slightly more complex manufacturing, provide deterministic positioning that significantly improves reliability compared to conventional symmetric designs.
3Measurement precision
If standard gear ratios are used in the transmission device, then the ease of manufacture is improved, but the adjustment precision deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the diameter ratio of the worm gear to the spur gear to be greater than 1 (specifically mentioned as 1.5 in embodiments). This parameter change in the gear system provides a mechanical advantage that amplifies the rotational movement of the transmission shaft into finer axial movements of the connecting rod engagement element. Combined with the polygonal positioning structures that define precise zero positions, this modified gear ratio enables the system to achieve adjustment precision within ±0.5mm, representing a significant improvement over conventional gear ratios used in standard transmission devices.
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 device enhances adjustment precision by compensating for manufacturing and assembly tolerances, enabling accurate remote electrical tilt control of phase shifters in base station antennas.
Implementation Method 1
a worm driven by the transmission shaft, a worm gear meshed with the worm, at least one spur gear disposed on a same connecting shaft as the worm gear
Implementation Method 2
the spur gear and the worm gear being fixedly disposed relative to each other and the connecting rod engagement element having a rack meshed with the spur gear
Implementation Method 3
a motor, a screw driven by the motor, a transmission shaft, and a linkage system, the linkage system is connected with the screw via the transmission shaft
Implementation Method 4
the worm has a shaft bore for connection with the transmission shaft, an inner surface of the shaft bore has a polygonal structure, the transmission shaft at least partially has a polygonal portion for embedding into the shaft bore
Implementation Method 5
the connecting rod engagement element having a rack meshed with the spur gear, so that the worm is capable of driving the worm gear to rotate with the spur gear, and the spur gear drives the connecting rod engagement element via the rack to move in an axial direction
Data Source
AI summary
A transmission device for a base station antenna includes a motor, a screw driven by the motor, a transmission shaft, and a linkage system. The linkage system is connected with the screw via the transmission shaft, so that the screw drives the linkage system via the transmission shaft. The linkage system includes: a worm driven by the transmission shaft, a worm gear meshed with the worm, at least one spur gear disposed on a same connecting shaft as the worm gear, and at least one connecting rod engagement element. The spur gear and the worm gear are fixed relative to each other. The connecting rod engagement element has a rack meshed with the spur gear, so that the worm drives the worm gear to rotate with the spur gear, and the spur gear drives the connecting rod engagement element via the rack to move in an axial direction of the transmission shaft.