Pancake Motor Actuator with Flex Gear for Cable Drive
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Solution Overview
Problem
Existing actuating devices for cables lack efficient mechanisms to transmit rotational motion over long distances with high torque and precision, particularly in applications like vehicle seat mechanisms, where reliable actuation of locks and latches is required.
Innovation Solution
The actuating device incorporates a pancake motor assembly with planetary gears and a flex gear system, which translates rotational motion into linear motion through a cable, allowing for precise actuation of a seat-back latch by rotating a shaft that engages with a flex gear and output member, enabling 360-degree movement of the cable for effective lock and latch operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a traditional motor assembly with gear system is used to transmit rotational motion, then the actuating device can provide sufficient torque, but the device size increases and power density decreases
Solution Approach 1:
The patent combines the motor assembly and gear system into a single integrated unit with shared housing and mounting structures. The motor housing serves dual purposes as both motor enclosure and gear system housing, eliminating the need for separate housings and reducing overall device volume while maintaining required torque output.
Solution Approach 2:
The gear system is nested within the motor assembly housing, with planetary gears positioned inside the motor housing cavity. This nesting arrangement allows the gear system to occupy space that would otherwise be unused, reducing the overall device footprint without compromising torque transmission capability.
2Device complexity
If a rigid gear system is used to transmit rotational motion, then the mechanism is simple in structure, but backlash occurs reducing actuation precision
Solution Approach 1:
The patent replaces the traditional rigid gear system with a dynamic flex gear mechanism. The flex gear uses elastic deformation to engage and disengage teeth, allowing for precise control of the cable actuation cycle. This dynamic approach eliminates backlash while maintaining structural simplicity, as the flex gear's elasticity provides automatic tooth engagement without requiring complex adjustment mechanisms.
3Ease of operation
If a conventional cable actuation mechanism is used, then the cable can be actuated, but return springs are required adding device complexity
Solution Approach 1:
The flex gear mechanism serves its own return function through its elastic properties. As the motor drives the flex gear through its actuation cycle, the elastic deformation stores energy that automatically returns the flex gear to its neutral position when motor power is removed. This self-returning mechanism eliminates the need for separate return springs, reducing device complexity while maintaining ease of cable actuation.
4Length of moving object
If the output member rotates 360 degrees to actuate the cable, then the cable can move between retracted and extended positions, but the connector path length increases
Solution Approach 1:
The patent transitions the connector movement from a linear path to a rotational path by 360 degrees. The connector is positioned on the periphery of the output member and rotates with it, allowing the cable to be actuated through rotational motion rather than linear translation. This dimensional change reduces the connector path length while achieving the same cable movement range between retracted and extended positions.
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
This configuration provides high torque and precise control, enabling efficient actuation of vehicle seat mechanisms, reducing backlash and the need for return springs, while maintaining a compact design with high power density.
Implementation Method 1
at least two planetary gears disposed within the interior of the housing with the at least two planetary gears coupled to the motor assembly
Implementation Method 2
a flex gear disposed within the interior of the housing with the flex gear having an inner surface and an outer surface with the inner surface partially engaged with the planetary gears
Data Source
AI summary
The invention provides an actuating device for actuating a cable. The actuating device comprises a housing defining an interior and a motor assembly including a shaft. The actuating device also comprises at least two planetary gears and a flex gear having an inner surface and an outer surface with the inner surface partially engaged with the planetary gears. The actuating device additionally comprises an output member having a drive portion and a mounting interface with the drive portion engaged with a section such that the output member is rotatable relative to the housing when the shaft rotates. The actuating device additionally comprises a connector coupled to the mounting interface for securing the cable to the mounting interface. The connector moves relative to the housing and in unison with the output member during the rotation of the output member for activating the cable during operation of the actuating device.