Cinch Actuator Cycloidal Drive for Low-Backlash Latch Closing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle closure latches with power-operated cinch mechanisms suffer from complexity, excessive backlash, high cost, noise, and inefficiency due to numerous interacting components, requiring significant travel and space, and have low torque capacity.
Innovation Solution
A closure latch assembly with a cycloidal drive mechanism that includes a power actuator, ratchet, pawl, and cam, which reduces backlash, increases torque capacity, and operates quietly by using a cycloidal drive to move the ratchet from a secondary to a primary striker capture position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If gear reductions and levers are used in cinch mechanisms, then torque capacity is increased, but device complexity increases and backlash increases
Solution Approach 1:
The patent extracts and eliminates the gear reduction and lever components from the cinch mechanism, replacing them with a direct-drive motor and a cam-based ratchet actuation system. This removal of intermediate components reduces device complexity while maintaining torque capacity through direct motor-to-ratchet connection.
Solution Approach 2:
Instead of using gear reductions to multiply torque from a small motor, the invention inverts the approach by using a high-torque motor that directly drives the ratchet through a cam mechanism. The cam converts rotational motion into the linear motion needed to actuate the ratchet, eliminating the need for complex gear trains.
2Force
If gear reductions and levers are used in cinch mechanisms, then torque capacity is increased, but backlash increases
Solution Approach 1:
The patent removes gear reductions and levers from the system, eliminating the sources of backlash. The direct-drive motor connects to the cam mechanism that actuates the ratchet, ensuring no intermediate components to create play or backlash in the torque transmission path.
3Force
If gear reductions and levers are used in cinch mechanisms, then torque capacity is increased, but the package size increases
Solution Approach 1:
The patent extracts the bulky gear reductions and levers from the cinch mechanism, replacing them with a compact direct-drive motor and cam assembly. This elimination of intermediate mechanical components significantly reduces the overall package size while maintaining the necessary torque capacity for ratchet actuation.
4Force
If numerous interacting components are used in cinch mechanisms, then torque capacity is increased, but noise increases
Solution Approach 1:
The patent removes multiple interacting mechanical components including gear reductions and levers that generate noise through meshing and movement. The simplified direct-drive motor with cam mechanism produces significantly less noise, eliminating the harmful acoustic byproducts of complex mechanical interactions.
5Force
If significant travel is required to effect actuation, then torque capacity is increased, but loss of time increases
Solution Approach 1:
The cam mechanism is designed to convert rotational motor motion into the precise linear motion needed for ratchet actuation in a single, predetermined motion path. This preliminary design of the motion trajectory eliminates the need for excessive travel and pre-travel, reducing actuation time while maintaining torque capacity.
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 cycloidal drive mechanism provides high torque capacity, low backlash, and compact design with reduced noise, enhancing the efficiency and durability of the closure latch assembly.
Implementation Method 1
a cycloid disk is configured to be driven in eccentric fashion by the cam
Implementation Method 2
a cam is fixed to output gear for eccentric rotation about a rotational axis of output gear
Implementation Method 3
the ferrule is configured for lost motion within the slot as the output disk rotates about the rotational axis of the output gear, thereby allowing a buildup of inertia prior to cinching the ratchet
Data Source
AI summary
A cinch power actuator for a closure latch assembly of a vehicle closure member includes a motor, an output gear configured to be driven in response to energization of the motor, a cam fixed to output gear for eccentric rotation about a rotational axis of output gear, a cycloid disk configure to be driven in eccentric fashion by the cam, and an output disk configured to be driven about the rotational axis of output gear by the cycloid disk, wherein the output disk is configured to drive a cable to move a ratchet of the closure latch assembly from a secondary striker capture position to a primary striker capture position.