Fixing Structure Spacer for Electrical Connection Box Axial Force
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Solution Overview
Problem
Electrical connection boxes with large attaching hole diameters experience reduced axial force due to bending of washers or bolt necks, leading to insufficient fixation and potential buckling, especially when using wide plain washers.
Innovation Solution
A fixing structure that includes a spacer with a U-shaped opening and rolling bearings, allowing it to rotate and maintain contact with the washer and attaching target, preventing axial force reduction and buckling by distributing the force effectively even with large hole diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a large attaching hole diameter is used to accommodate position tolerance, then the ease of operation is improved, but the axial force is reduced due to washer or bolt neck bending
Solution Approach 1:
The patent introduces a spacer as an intermediary component between the washer and the attaching hole. This spacer has a cylindrical shape with an opening that fits over the attaching bolt, and it includes a curved surface that contacts the bolt. The spacer acts as a mediator to transmit axial force from the washer to the attaching target while preventing bending of the washer or bolt neck, thus resolving the contradiction between large hole diameter and sufficient axial force transmission
Solution Approach 2:
The patent changes the physical parameters of the attaching structure by introducing the spacer with specific geometric parameters (cylindrical shape, opening diameter matching the bolt, curved contact surface). This parameter change allows the system to maintain sufficient axial force transmission even when the attaching hole diameter is enlarged to accommodate position tolerance
2Ease of operation
If a wide plain washer is used to accommodate large hole diameter, then the ease of operation is improved, but the axial force is reduced due to washer bending
Solution Approach 1:
The spacer serves as an intermediary between the wide plain washer and the attaching hole, preventing the washer from bending under load. The spacer's rigid cylindrical structure with curved contact surface provides a stable force transmission path, allowing the use of a wide washer for ease of attachment without sacrificing axial force transmission capability
Solution Approach 2:
The spacer provides beforehand cushioning by pre-positioning itself between the washer and the attaching target, preventing washer bending before the axial force is applied. The curved surface of the spacer contacts the attaching bolt to provide support and prevent buckling of the seating surface in advance
3Strength
If a metallic sleeve or flanged collar is used to prevent buckling, then the strength is improved, but the device complexity increases
Solution Approach 1:
The spacer performs multiple functions simultaneously: it prevents washer bending, prevents bolt neck bending, prevents seating surface buckling, and transmits axial force. This multi-functional design replaces the need for separate metallic sleeves or flanged collars, reducing device complexity while maintaining strength
Solution Approach 2:
The patent merges the functions of preventing buckling and transmitting axial force into a single spacer component. By combining these protective and force transmission functions into one element, the fixing structure becomes simpler compared to using separate metallic sleeves or flanged collars
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 proposed solution ensures stable axial force transmission and prevents buckling, enhancing the assembly process and maintaining structural integrity without the need for specialized nuts or reinforced bolts, thus reducing costs and improving workability.
Implementation Method 1
the spacer has an opening on a cylindrical side surface thereof and is capable of rotating around the axial direction of the attaching bolt in a state where the attaching bolt is inserted into the opening
Implementation Method 2
the spacer has a rolling bearing on at least one of a cylindrical inner circumferential surface and a cylindrical outer circumferential surface thereof, and rotates around the axial direction of the attaching bolt with the rolling bearing interposed between the spacer and the attaching bolt
Data Source
AI summary
A fixing structure includes an attaching portion, a nut, and a spacer. The attaching portion has an attaching hole through which an attaching bolt provided to a vehicle body is inserted. The nut fixes the attaching portion to the vehicle body by being tightened to the attaching bolt with a washer interposed between the nut and the attaching portion. The spacer is disposed between an inner circumferential surface of the attaching hole and an outer circumferential surface of the attaching bolt, and is in contact with the vehicle body and the washer in an axial direction of the attaching bolt in a state where the attaching bolt and the nut are tightened. The spacer has an opening on a cylindrical side surface thereof and is capable of rotating around the axial direction of the attaching bolt in a state where the attaching bolt is inserted into the opening.