Torque Rod Asymmetric Branches Collision Load Breakage
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Solution Overview
Problem
Conventional torque rods face challenges in maintaining sufficient strength during normal load input while facilitating breakage under collision load input, especially when suspending heavy power units with high displacement, requiring a greater difference in strength performance between normal and collision load inputs.
Innovation Solution
The torque rod design includes a first annular portion elastically connected to a power unit, a second annular portion elastically connected to a vehicle, a connection stay portion with a thicker upper branch and thinner lower branch, and a wall portion that forms a cavity, with a projection portion positioned off-center to concentrate stress during collision loads, enhancing the strength difference between normal and collision load inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the torque rod is designed with uniform thickness to maintain sufficient strength during normal load input, then the strength during normal operation is improved, but the ability to break easily during collision load input deteriorates
Solution Approach 1:
The torque rod employs local quality by varying the thickness of different parts: the first and second annular portions have a first thickness, while the connection stay portion has a second thickness that is smaller than the first thickness. This local variation in dimensional parameters creates regions of different strength, allowing the torque rod to maintain sufficient overall strength for normal operation while having specific weaker regions that will break during collision loads.
2Object-affected harmful factors
If the torque rod is designed with asymmetric branch portions (thinner lower branch) to facilitate breakage during collision, then the breakage capability is improved, but the strength during normal load input deteriorates
Solution Approach 1:
The torque rod applies asymmetry by making the lower branch portion of the connection stay thinner than the upper branch portion. The connection stay portion includes a first thickness in the radial direction and a second thickness in the axial direction, where the second thickness is smaller than the first thickness. This asymmetric design creates a preferred breakage path during collision while maintaining sufficient strength through the thicker annular portions and upper branch.
3Stability of the object's composition
If the wall portion is positioned at the axial center of the first annular portion, then the structural symmetry is improved, but the stress concentration effect during collision load deteriorates
Solution Approach 1:
The wall portion is positioned asymmetrically relative to the first annular portion, specifically at a location that is not at the axial center but rather at a position that creates effective stress concentration during collision loads. This asymmetric positioning of the wall portion, which connects the first annular portion and the connection stay portion, optimizes the stress distribution to facilitate breakage during collision while maintaining adequate structural stability.
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
This design ensures sufficient strength during normal load input and easy breakage under collision load input, effectively protecting the power unit and its structures by ensuring the torque rod breaks at a predetermined load during collisions without compromising normal operation.
Implementation Method 1
a first annular portion (11) elastically connected to a first attachment member (14) located on an inner circumferential side of the first annular portion
Implementation Method 2
a projection portion (23) projecting in an axial direction of the first annular portion from a site (22) of the first annular portion exposed to the cavity (21)... the input is concentrated at the projection portion to facilitate breakage of the torque rod from the projection portion
Implementation Method 3
a lower branch portion (17) that has lower bending strength than the upper branch portion (16) and connects with a lower part of the first annular portion
Data Source
Figure 1
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AI summary
A torque rod comprises: a first annular portion 11 elastically connected to a first attachment member 14 to be connected to a power unit; a second annular portion 12 elastically connected to a second attachment member 15 to be connected to a vehicle; a connection stay portion 13 extending radially outward from an outer circumferential part of the second annular portion 12 and connecting with an outer circumferential part of the first annular portion 11, and including an upper branch portion 16 and a lower branch portion 17 having lower bending strength than the upper branch portion 16; a wall portion 20 connecting with the first annular portion 11 and the connection stay portion 13, and forming a cavity 21 to which part of the first annular portion 11 is exposed; and a projection portion 23 projecting in an axial direction of the first annular portion 11 from a site 22 of the first annular portion 11 exposed to the cavity 21.