Rotation Transmission Device Torque Measurement Resolution
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Solution Overview
Problem
Conventional torque measurement devices for automatic transmissions face challenges in maintaining sufficient elastic torsional deformation and resolution, especially when the torsional rigidity of the rotary shaft is high, and require complex housing processing and multiple sensors, making them difficult to install and precise.
Innovation Solution
A rotation transmission device using a pair of encoders and one sensor unit, with a hollow concentric rotary shafts and a torsion bar that allows for relative rotation between the end sections, enabling increased elastic torsional deformation and improved torque measurement resolution, regardless of the axial space between gears, and simplifying housing processing by reducing the number of sensors and supports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional torque measurement devices use two sensors separated in the axial direction, then torque measurement is possible, but the device complexity increases and housing processing becomes complicated
Solution Approach 1:
The patent combines two separate sensors into a single sensor unit that simultaneously detects both encoders. This merging reduces the number of sensors from two to one, simplifies housing processing by eliminating the need for two separate supporting sections, and maintains the capability to measure torque through relative displacement detection between encoders.
Solution Approach 2:
The single sensor unit is designed to perform multiple functions: it detects both encoders simultaneously and provides torque measurement capability. This multi-functional design eliminates the need for separate sensors for each encoder, reducing device complexity while maintaining measurement precision.
2Strength
If the torsional rigidity of the rotary shaft is high, then the shaft is stronger, but the elastic torsional deformation is insufficient and torque measurement resolution becomes low
Solution Approach 1:
The patent transitions from measuring torque through axial displacement to measuring it through relative rotational displacement between encoders mounted on concentric hollow rotary shafts. This dimensional change allows the use of a single sensor unit that detects rotational phase differences, enabling sufficient measurement resolution even when axial elastic torsional deformation is limited by high torsional rigidity.
3Measurement precision
If two sensors are installed separated in the axial direction, then torque measurement is possible, but it becomes difficult to arrange two harnesses running from the sensors
Solution Approach 1:
By merging two separate sensors into a single sensor unit, the patent reduces the number of harnesses from two to one. This single harness connects the sensor unit to the control unit, eliminating the complexity of arranging and managing two separate harnesses while maintaining full torque measurement functionality.
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 effectively increases the resolution of torque measurement and simplifies the installation and processing of the housing by using a single sensor and fewer supports, while maintaining precision and handling large or small axial spaces between gears.
Implementation Method 1
the middle section in the axial direction of the torsion bar undergoes elastic torsional deformation when torque is transmitted
Implementation Method 2
the magnetic characteristics of these encoders 2 change in an alternating manner at a uniform pitch in the circumferential direction
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A rotation transmission device having a high torque measurement resolution is provided. The rotation transmission device is provided with: a rotary-shaft unit (6) having a first and second rotary shaft (13, 14) combined so as to be coaxial and such that the end sections thereof can rotate relative to each other and a torsion bar (15) that is provided on the inner-diameter side of the first and second rotary shafts so as to be coaxial therewith, has one end section connected to the first rotary shaft (13), and has the other end section connected to the second rotary shaft (14); a first gear (7) fastened to the outer peripheral surface of the first rotary shaft (13); a second gear (8) fastened to the outer peripheral surface of the second rotary shaft (14); a coupling shaft (9) provided on the inner-diameter side of the torsion bar (15) so as to be coaxial therewith, having one end section connected to one rotary shaft (13), and having the other end section protruding from an end of the torsion bar (15) in the axial direction; a first encoder disposed and fixed on the other end of the coupling shaft (9) so as to be coaxial with the first rotary shaft (13) and having a first detected section (39); a second encoder fastened on the other end of the second rotary shaft (14) so as to be close to the first encoder and having a second detected section (40); and a sensor unit having at least one sensor (42a, 42b) that faces the first and second detected sections (39, 40).