Front Fork Damping Force Adjuster With Noncircular Push Rod
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing damping force adjusting apparatuses for front forks are complex, prone to operational failures, and poorly suited for front forks with thin piston rods, as they require multiple parts and specific directional adjustments, limiting their applicability and assembly performance.
Innovation Solution
A damping force adjusting apparatus with a simplified structure featuring a push rod with a noncircular cross-section, coaxially disposed adjusting portions, and a needle valve that adjusts the bypass passage, allowing for rotational and axial movement, which reduces the number of parts and eliminates directional assembly constraints, enabling effective adjustment of front forks with thin piston rods from an upper end surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two adjusting portions with gear train and tapered surface complex are provided, then the adjuster rod can be moved in rotational and axial directions, but the number of parts increases and operational failure becomes more prone
Solution Approach 1:
The patent combines the two separate adjusting portions into a single integrated adjusting portion that can perform both rotational and axial adjustments. The single adjusting portion includes a gear train that engages with a noncircular groove on the push rod, allowing both rotational and axial movements to be achieved through one component rather than two separate complexes, thereby reducing the number of parts while maintaining adjustment functionality
Solution Approach 2:
The single adjusting portion is designed to perform multiple functions: it can adjust the push rod in both rotational and axial directions through its gear train mechanism. This multi-functional design eliminates the need for separate adjusting portions for each direction, reducing overall device complexity while preserving comprehensive adjustment capability
2Ease of operation
If two adjusting portions are provided in the lateral direction perpendicular to the adjuster rod, then rotational and axial adjustments are possible, but directional properties limit assembling position and reduce assembling performance
Solution Approach 1:
The patent employs a noncircular groove on the push rod that is asymmetric in shape, allowing the gear train to engage and transmit both rotational and axial movements. This asymmetric design within a single adjusting portion positioned on the axial center eliminates the need for lateral positioning, removing directional constraints on assembly while maintaining full adjustment functionality
3Ease of operation
If the needle valve is disposed around the outer periphery of the push rod, then the bypass passage can be adjusted, but additional space is required which limits applicability to front forks with thin piston rods
Solution Approach 1:
The needle valve is nested within the hollow interior of the push rod, which itself is located inside the hollow piston rod. This nested arrangement allows the needle valve to be positioned centrally within the existing hollow structures rather than requiring additional peripheral space, making the design applicable to front forks with thin piston rods while maintaining bypass adjustment functionality
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 provides a robust, reliable, and easily assembled damping force adjustment system for front forks, reducing operational failures and enhancing assembly performance, while accommodating thin piston rods without requiring additional space for the needle valve around the push rod.
Implementation Method 1
the bypass passage is provided with the needle valve
Implementation Method 2
A spring which collides against the push rod in the axial direction biases the compression-side damping valve in its closing direction
Implementation Method 3
the piston rod is provided at its tip end with a piston which slides in the working oil chamber, the working oil chamber of the inner tube is divided by a piston into a piston rod-side oil chamber and a piston-side oil chamber
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In a damping force adjusting apparatus 40A of a front fork 10, the hollow portion of the piston rod 23 is provided with a push rod 70 having a noncircular cross section, the push rod 70 can move in the rotational direction and the axial direction, a first adjusting portion 80 which moves the push rod 70 in the rotational direction and a second adjusting portion 90 which moves the push rod 70 in the axial direction are coaxially disposed on an extension of the push rod 70 at an upper portion of the front fork, the needle valve 85 which is slidably inserted into the noncircular cross section of the push rod 70 is threadedly engaged with the hollow portion of the piston rod 23, a spring 95 which collides against the push rod 70 in the axial direction biases the compression-side damping valve 41A in its closing direction.