Cab Bracket Deformation Structure for Controlled Displacement
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Solution Overview
Problem
Existing vehicle designs face challenges in dimensioning cab brackets and securing bolts to break off during collisions while withstanding everyday use stresses, making it difficult to ensure controlled rupture and maintain cab integrity.
Innovation Solution
A cab bracket with a deformable section featuring a primary leg for normal use and an auxiliary leg with notches that rupture during collisions, allowing controlled rearward displacement of the cab, and an additional notch to facilitate further movement by causing subsequent primary leg rupture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cab bracket is designed to break off during collision to allow cab displacement, then the cab integrity is improved, but the bracket must be dimensioned to withstand fatigue stresses during everyday use
Solution Approach 1:
The cab bracket is divided into two distinct functional segments: a primary load-carrying leg that remains intact during normal operation, and an auxiliary leg with a controlled rupture section that breaks during collision. This segmentation allows each part to be optimized for its specific function - the primary leg for withstanding fatigue stresses and the auxiliary leg for controlled failure.
Solution Approach 2:
The auxiliary leg is designed with a localized weakened section (reduced cross-sectional area) at a specific position, creating a controlled rupture point. This local quality change allows the bracket to have different mechanical properties at different locations - strong elsewhere to withstand normal loads, and weak at the rupture section to fail controllably during collision.
2Ease of operation
If the bracket is designed to rupture at a predetermined force level during collision, then the controlled displacement is achieved, but it becomes difficult to withstand fatigue stresses during everyday use
Solution Approach 1:
A notched indication is pre-formed in the auxiliary leg during manufacturing, creating a predetermined rupture point with reduced cross-sectional area. This preliminary action ensures that during collision, the rupture occurs at the predetermined location and force level, while the bracket elsewhere maintains sufficient strength to withstand normal operational stresses.
Solution Approach 2:
The cross-sectional area parameter of the auxiliary leg is changed at a specific location to create a weakened section. This parameter change allows the bracket to exhibit different mechanical behavior at different locations - maintaining high strength and reliability during normal use, while enabling controlled rupture at the predetermined force level during collision.
3Ease of operation
If screws or rivets are used to hold beams together and break off during collision, then the cab displacement is enabled, but it is difficult to dimension the structure to resist both collision forces and everyday fatigue stresses
Solution Approach 1:
The auxiliary leg integrates the functions of both the structural connection element and the controlled failure element into a single component. Instead of using separate screws or rivets that need to be dimensioned for both collision failure and normal load resistance, the auxiliary leg itself is designed with the controlled rupture section, simplifying the dimensioning process.
Solution Approach 2:
The controlled failure function is extracted from the primary load-carrying structure and placed in the auxiliary leg. This separation allows the primary leg to be optimized purely for withstanding fatigue stresses and collision forces, while the auxiliary leg handles the controlled rupture function, reducing the overall complexity of structure dimensioning.
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 ensures controlled rupture of the cab bracket during collisions, maintaining cab integrity and allowing rearward displacement, while minimizing fatigue effects on the auxiliary leg during normal use.
Implementation Method 1
The rear portion comprises an auxiliary leg, arranged to break and permit longitudinal displacement only during a collision event
Implementation Method 2
a deformation structure comprising a rigid bracket provided with weakening means for achieving a controlled rupture of the bracket when subjected to collision forces
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a vehicle (1) comprising a chassis (3) and, supported on said chassis (3), a cab (2) with an integrated cab bracket (14), said cab (2) being arranged, in the event of collision in the direction from the front, to be displaced backwards relative to the chassis (3), wherein the cab bracket (14) comprises a front portion (15) and a rear portion (16) and is arranged to connect the cab (2) to the chassis (3) at a lower portion of the cab bracket (14). The front portion (15) comprises a load carrying primary leg (15a), arranged to absorb longitudinal, vertical and transverse forces between the cab and the chassis, and the rear portion (16) comprises an auxiliary leg (16a), arranged to break and allow longitudinal displacement during a collision event, and that at least the rear portion (16) is provided with at least one notch (17, 18) providing an indication of fracture, wherein the auxiliary leg is arranged to rupture when subjected to longitudinal collision forces over a predetermined magnitude.