Electric motor module with integrated cam switches incorporating a single wiring connection point
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Solution Overview
Problem
Existing motorized mechanisms in appliances face challenges with multiple segregated wiring connections, leading to assembly time inefficiencies and potential improper connections, as well as dimensional tolerance stack-up issues due to radial and angular positional relationships of switches and cams, which increase manufacturing costs and risk of product failure.
Innovation Solution
An electric motor assembly with a synchronous gear motor and cam-actuated switches integrated into a single housing, eliminating the need for rigid or flexible circuit boards and secondary cams or plungers, featuring a single point power connection and precise radial and angular positioning of switches, reducing tolerance stack-up and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple segregated wiring connection points are used for switches and motor, then each component can be independently connected, but assembly time increases and improper connections may occur
Solution Approach 1:
The patent combines multiple segregated wiring connection points into a single integrated wiring connection point. The microswitch terminals and motor terminals are both connected to a common wiring harness connector, eliminating the need for separate connections. This merging reduces the number of connection operations during assembly, thereby reducing assembly time while maintaining connection reliability through a unified connection interface.
Solution Approach 2:
The single wiring connection point serves multiple functions: it provides electrical connection for the motor, all microswitch terminals, and optionally the linear cam actuated switch. This multi-functional connector replaces what would traditionally require multiple separate connectors, simplifying the wiring system and reducing assembly complexity.
2Ease of manufacture
If switches are mounted on adjacent brackets with independent dimensional tolerances, then manufacturing is simplified, but dimensional tolerance stack-up decreases sensing accuracy
Solution Approach 1:
The patent merges the mounting functions into a single integrated housing structure. The microswitches are mounted on a common baseplate or housing that is directly attached to the motor assembly, eliminating the need for separate adjacent brackets. This unified mounting structure eliminates the dimensional tolerance stack-up between multiple brackets while maintaining ease of manufacture through a single integrated component.
Solution Approach 2:
The housing is designed with integrated mounting features that precisely position the microswitches relative to the cam. By incorporating the mounting structure as an integral part of the housing rather than separate brackets, the design achieves precise positioning through the housing's inherent dimensional stability while keeping the manufacturing process simple.
3Reliability
If rigid or flexible circuit boards are used to connect switches and motor, then a single point wiring connection is achieved, but cost and solder connection failure risks increase
Solution Approach 1:
The patent extracts the circuit board from the system entirely. Instead of using rigid or flexible circuit boards to connect the switches and motor, the design uses direct terminal connections to the wiring harness. This eliminates the circuit board layer, removing the associated costs, solder connections, and potential failure modes while achieving the same single-point wiring connection objective through a simpler terminal-based approach.
Solution Approach 2:
The patent replaces the electrical connection method (circuit boards with solder joints) with a mechanical connection method (terminal blocks or direct wire connections to the wiring harness). This substitution eliminates the need for soldering operations and circuit board assembly, reducing complexity and potential failure points while maintaining reliable electrical connections.
4Ease of operation
If secondary linear cam or plunger is added to activate switch, then switch actuation is achieved, but device complexity and tolerance stack-up increase
Solution Approach 1:
The patent merges the cam and switch actuation functions into a single integrated cam structure. The radial cam on the motor shaft directly actuates the microswitches without requiring a separate linear cam or plunger. This unified cam design eliminates the additional components and their associated tolerances, reducing overall mechanism complexity while maintaining effective switch actuation.
Data Source
AI summary
Provided is an electric motor assembly and method for assembling an electric motor assembly within an appliance. The electric motor assembly eliminates the use of a rigid or flexible circuit board. It also eliminates the need for soldering contacts between the electrical switches, circuit board and motor which can increase the possibility of operational failures. The electric motor assembly further provides a single power point wiring connection between the switch and motor terminals and connector port allowing the motorized device to communicate with an appliance controller. Furthermore, by positioning certain mechanical components for operating electrical switches on the baseplate of the electric motor assembly and eliminating secondary components on adjacent brackets, a reduction in the dimensional tolerance stack-up among the electrical switches can be obtained.