Electronic Throttle Control Assembly Eccentric Pin Adjustment
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Solution Overview
Problem
Existing electronic throttle control assemblies face challenges in precisely adjusting the default air flow position of the throttle plate due to the large diameter of set screws required, which complicates the assembly process and limits precision to ±0.1° tolerance.
Innovation Solution
An excentric pin is used to adjust the position of the spring, allowing for precise adjustment of the valve plate's angle within ±0.10° by sliding into a housing aperture and being secured with a driver, reducing the assembly tolerance by a factor of 3.5, and featuring a cam and knurled or ribbed surface for secure positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If set screws are used to adjust the valve plate position, then the default air flow setting can be adjusted, but the screw diameter becomes too large to position properly inside the gearbox
Solution Approach 1:
An excentric pin is introduced as an intermediary component between the housing and the spring assembly. The pin fits within the existing aperture and uses an excentric cam mechanism to convert rotational motion into linear displacement, allowing adjustment of the spring position and thereby the valve plate angle without requiring large external set screws
Solution Approach 2:
The adjustment mechanism transitions from a linear insertion approach (set screws) to a rotational dimension (excentric pin). The excentric pin is rotated within the aperture to achieve adjustment, utilizing angular movement to control the spring position and valve plate angle, thus solving the space constraint problem
2Ease of operation
If set screws are used for adjustment, then the default air flow can be set, but the assembly process becomes more complex requiring securing and closing off access holes
Solution Approach 1:
The excentric pin is designed to be self-contained within the housing aperture. Once rotated to the desired position, the pin itself serves as the adjustment mechanism without requiring additional securing operations or access hole closure, as the excentric geometry maintains the adjusted position through its cam action on the spring
3Manufacturing precision
If traditional adjustment methods are used, then the valve plate can be positioned, but the assembly tolerance remains at ±0.1° which requires significant effort to achieve
Solution Approach 1:
The excentric pin changes the geometric parameters of the adjustment mechanism. By varying the rotation angle of the excentric pin, the effective lever arm and cam position change, providing fine control over the spring compression and thereby achieving precise valve plate angle adjustment with reduced assembly effort
Solution Approach 2:
The excentric pin introduces dynamic adjustment capability where the cam position can be continuously varied through rotation. This dynamic mechanism allows for precise positioning of the spring and valve plate by simply rotating the pin to the desired angle, rather than requiring complex multi-step adjustment procedures
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 excentric pin enables precise adjustment of the valve plate's angle, reducing assembly complexity and improving airflow control by allowing for finer adjustments and secure locking, thus enhancing the throttle control assembly's performance.
Implementation Method 1
The excentric pin is turned using some type of driver. In one embodiment, the driver has multiple external splines, where the excentric pin is located in an aperture of the housing, and secured against rotation after adjustment to the desired position.
Data Source
AI summary
An excentric pin for an electronic throttle control assembly, which is used to adjust the default position of at least one spring used to control the position of a valve plate, where the valve plate is located in an opening of a housing in the electronic control assembly. The excentric pin is used to adjust the default angle of the valve plate to have an angular tolerance of +/−0.10°. The excentric pin is slideably pressed into an aperture of the housing of the electronic throttle control assembly, and turned using some type of driver. The electronic throttle control assembly may be a one-spring design, or a two-spring design, where the two-spring design requires only one spring pin and the excentric pin. Also, the excenter pin may be used to adjust the position of the sector gear, e.g., function as the lower mechanical stop to provide a minimum opening angle for low leakage, and a minimum opening angle to avoid throttle plate corking into opening of the housing.