Electronic Expansion Valve Planetary Gear for Precise Flow Control
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Solution Overview
Problem
Conventional electronic expansion valves face challenges in achieving high precision and miniaturization while increasing the adjusting range of the flow rate, as traditional spur gear deceleration mechanisms require increased volume and complexity, leading to reduced transmission efficiency and stability.
Innovation Solution
The implementation of a planetary gear deceleration mechanism with internal meshing gears, which reduces the overall size of the deceleration mechanism and allows for a higher deceleration ratio, enabling precise control of the valve needle and increasing the flow rate adjusting range, while meeting the requirements of miniaturization and high precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the deceleration ratio is increased to improve control precision and extend flow rate adjusting range, then the control precision and adjusting range are improved, but the volume of the gear decelerator increases
Solution Approach 1:
The planetary gear mechanism nests multiple gears (sun gear, planetary gears, ring gear) within a compact configuration, allowing one gear to be positioned inside another. This nesting arrangement achieves high deceleration ratios without increasing the external volume of the decelerator, as the multiple gear stages are contained within the same radial envelope.
Solution Approach 2:
The planetary gear mechanism transitions from a linear arrangement of gears to a radial/dimensional configuration where gears are arranged around a central axis. This dimensional change allows multiple gear stages to be stacked radially rather than sequentially in one direction, achieving high deceleration ratios within a compact cylindrical volume.
2Measurement precision
If the number of stages of the gear decelerator is increased to improve control precision, then the control precision is improved, but the volume of the gear decelerator increases and the transmission efficiency decreases
Solution Approach 1:
The planetary gear mechanism nests multiple gears (sun gear, planetary gears, ring gear) within a compact configuration, allowing one gear to be positioned inside another. This nesting arrangement achieves high deceleration ratios without increasing the external volume of the decelerator, as the multiple gear stages are contained within the same radial envelope.
Solution Approach 2:
The planetary gear mechanism merges multiple gear functions into a single integrated mechanism. Instead of using separate gear stages that would require multiple independent gear pairs, the planetary mechanism combines the sun gear, planetary gears, and ring gear into one unified deceleration system that achieves the same or higher deceleration ratio with fewer discrete components.
3Adaptability or versatility
If the deceleration ratio is increased to extend flow rate adjusting range, then the adjusting range is extended, but the transmission efficiency and stability of the system are reduced
Solution Approach 1:
The planetary gear mechanism merges multiple gear functions into a single integrated mechanism. Instead of using separate gear stages that would require multiple independent gear pairs, the planetary mechanism combines the sun gear, planetary gears, and ring gear into one unified deceleration system that achieves the same or higher deceleration ratio with fewer discrete components.
Solution Approach 2:
The patent replaces the traditional multi-stage spur gear mechanical system with a planetary gear mechanism that provides more efficient power transmission. The planetary mechanism's inherent mechanical advantages include better load distribution across multiple contact points, reduced backlash, and higher transmission efficiency, thereby improving system stability and reliability while achieving extended adjusting ranges.
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 planetary gear deceleration mechanism achieves a larger deceleration ratio than traditional spur gear mechanisms, enhancing the accuracy of stroke control and expanding the flow rate adjusting range, thus addressing the limitations of conventional technologies in precision and miniaturization.
Implementation Method 1
a planetary gear deceleration mechanism including a planetary carrier, a planetary gear and a gearbox
Implementation Method 2
The other end of the box body is fixedly connected to the fixed inner gear ring
Implementation Method 3
a transmission mechanism having a nut and a screw rod which is matched with an internal thread of the nut
Data Source
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AI summary
Disclosed is an electronic expansion valve and a cooling system having same. The electronic expansion valve comprises: a valve seat (10), a valve needle (20) having open and closed positions, a drive mechanism (30) comprising a rotor (32) and a coil (31), a planetary gear speed-reduction mechanism (40) comprising a planetary carrier (41), a planetary gear (42) and a gearbox (43), and a transmission mechanism (50) comprising a nut (52) and a screw rod (51). The rotor (32), the planetary carrier (41) and the gearbox (43) are coaxially arranged, and the rotor (32) is fixedly connected to the planetary carrier (41) so as to drive the planetary carrier (41) to rotate along the axis thereof. The planetary gear (42) is sleeved on a first mounting shaft (411); the gearbox (43) comprises a box body (431), a fixed inner gear ring (432) and an output inner gear ring (433); the planetary gear (42) is simultaneously meshed with the fixed inner gear ring (432) and the output inner gear ring (433). The first end of the screw rod (51) is fixedly connected to the output inner gear ring (433), and the second end of the screw rod abuts the valve needle (20) so as to move the valve needle (20) between the open position and the closed position. The described electronic expansion valve not only may increase flow adjustment range but also achieves high precision and miniaturization.