Dynamic Clearance Adjustment in Engine Mounting Bolts
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Solution Overview
Problem
Motor vehicle assemblies, particularly engines, experience mechanical loading and noise due to thermal expansion and sudden lateral accelerations, which cause undesired position changes and torque misalignment, leading to increased mechanical stress and noise.
Innovation Solution
An assembly mount with a load-bearing elastomer block and a movable compensation element that adjusts the clearance of the fastening bolt within the housing opening, using a pressure chamber and flexible bellows to reduce or eliminate clearance in response to thermal and inertial forces, thereby preventing unwanted movements and loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the fastening bolt is made relatively movable in the housing opening to compensate for thermal expansion, then thermal expansion effects are compensated, but clearance remains which causes undesired position changes and noise during lateral accelerations
Solution Approach 1:
The patent applies dynamics by making the compensation element movable rather than fixed. The compensation element can dynamically adjust its position within the housing opening to provide clearance during thermal expansion while eliminating clearance during lateral accelerations, thus resolving the contradiction between thermal compensation and noise prevention
Solution Approach 2:
The patent changes the parameter of clearance dynamically. The compensation element modifies the clearance parameter between the fastening bolt and housing opening based on operating conditions - maintaining larger clearance for thermal expansion and reducing to minimal clearance for lateral acceleration scenarios, thereby eliminating the harmful effects
2Object-affected harmful factors
If the clearance of the fastening bolt is reduced to prevent position changes during lateral accelerations, then mechanical loading is reduced, but thermal expansion compensation capability is limited
Solution Approach 1:
The movable compensation element enables dynamic adjustment of clearance, allowing the system to have large clearance when thermal expansion occurs and small clearance when lateral accelerations occur, thus resolving the contradiction between thermal compensation and mechanical loading reduction
3Object-affected harmful factors
If a fixed buffer unit is used to dampen lateral abutment, then lateral movements are dampened, but the system cannot adapt to varying thermal and inertial conditions
Solution Approach 1:
The patent replaces the fixed buffer unit with a movable compensation element that can dynamically adjust its position. This dynamic structure adapts to varying conditions by providing appropriate clearance or constraint, thus resolving the contradiction between lateral dampening and adaptability
Solution Approach 2:
The compensation element changes the clearance parameter dynamically based on operating conditions, allowing the system to adapt to both thermal expansion and lateral acceleration scenarios, thereby achieving both lateral dampening and adaptability
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 reduces mechanical loading and noise by dynamically adjusting the clearance of the fastening bolt, ensuring stable engine mounting and minimizing mechanical stress during thermal and inertial events.
Implementation Method 1
a load-bearing spring which is connected to the housing and to the fastening bolt and which is in particular in the form of an elastomer block
Implementation Method 2
an elastomer material, such that a lateral abutment of the fastening bolt within the housing opening can be dampened by way of the buffer unit
Implementation Method 3
thermal expansion of the motor vehicle engine between the situation in which the motor vehicle engine is cold and the situation in which the motor vehicle engine has warmed at operating temperature can give rise to a considerable change in the relative position of the fastening bolt
Data Source
AI summary
An assembly mount for the movable fastening of a motor vehicle assembly (such as an engine) having a housing which is connectable to a motor vehicle body, a fastening bolt which is connectable to the motor vehicle assembly and which projects into the housing via a housing opening, a load-bearing spring which is connected to the housing and to the fastening bolt, wherein the load-bearing spring permits at least a relative movement of the fastening bolt in an opening plane of the housing opening within the housing opening, and a compensation element which is movable relative to the housing and relative to the fastening bolt and which serves for the variation of a movement clearance of the fastening bolt in the housing opening in the opening plane.