Cam Clutch Spring Retention for Easier Assembly and Thinner Units
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Solution Overview
Problem
The existing cam clutch units face challenges in machining complexity, handling difficulties during assembly, and increased wear and drag torque due to the need for circumferential grooves and axial spring engagement mechanisms, which complicate production and assembly.
Innovation Solution
A cam clutch unit design featuring cams with engagement steps and a cage ring with hook portions that restrict axial movement, allowing the spring to press the cams towards the other axial end, preventing detachment and tilting, and reducing machining steps and assembly complexity, while maintaining wear durability and minimizing drag torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If circumferential grooves are provided in the center part of cams and rollers for accommodating the annular spring, then the spring can be accommodated, but the machining complexity increases and the unit thickness cannot be reduced beyond a certain limit
Solution Approach 1:
The cam structure is segmented into two functional parts: the main body (without grooves) and the engagement step (with groove). The engagement step is a separate structural feature that houses the spring, while the main body maintains a simple cylindrical shape for easy machining. This segmentation allows the spring accommodation function to be separated from the main cam body, reducing overall machining complexity.
Solution Approach 2:
The spring accommodation groove is moved from the radial dimension (center part of the cam) to the axial dimension (engagement step on the end face). This dimensional relocation allows the spring to be accommodated in the axial direction rather than requiring radial grooves, simplifying the main cam body structure and enabling thinner unit thickness.
2Reliability
If the spring is positioned to press the cams radially inwards, then the cams are biased correctly, but the cams may tilt or lift radially outwards during transportation, causing handling difficulties
Solution Approach 1:
The cage ring is equipped with hook portions that preliminarily restrict the axial movement of the spring before the cam clutch unit is assembled and operational. This preliminary action prevents the spring from moving axially and causing cam detachment during transportation and assembly, while the hook portions are designed to allow the spring to press the cams towards the other axial end for proper radial biasing during operation.
Solution Approach 2:
The hook portions of the cage ring act as an intermediary mechanism between the spring and the external environment. They mediate the spring's axial movement by restricting it during handling while allowing the necessary pressing action during operation, thus resolving the contradiction between reliable cam biasing and ease of handling.
3Ease of operation
If the position of the spring is adjusted to press down the cams and prevent detachment, then handling during assembly improves, but the assembly of the spring itself becomes more difficult and sliding resistance increases
Solution Approach 1:
The hook portions are designed with a pressing part that dynamically allows the spring to press the cams towards the other axial end during operation. This dynamic design enables the spring to perform its biasing function while being restricted in the axial direction, preventing detachment during handling without increasing assembly complexity or sliding resistance.
4Ease of manufacture
If engagement steps are provided on the axial end face of cams for spring engagement, then machining steps are reduced, but the cams may still detach during transportation before assembly
Solution Approach 1:
The engagement step structure is merged with the axial end face of the cam, combining the spring engagement function with the existing cam geometry. This integration reduces the need for separate machining operations while the engagement step's geometry (with groove and axial positioning) works in conjunction with the cage ring's hook portions to prevent cam detachment during transportation.
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 design enhances handling ease during assembly, reduces production complexity, and improves wear durability and drag torque properties by preventing cam detachment and sliding resistance, while allowing for thinner unit thickness and easier assembly.
Implementation Method 1
an annular spring that biases the cams
Implementation Method 2
the cage ring having a plurality of hook portions that restrict an axial movement of the annular spring
Implementation Method 3
the hook portions having a pressing part that allows the spring to press the cams towards an other axial end
Data Source
AI summary
To provide a cam clutch unit that is easy to handle before assembly, with its components prevented from lifting or detachment, and that allows production with fewer machining steps and a lower level of difficulty, while also enabling unit thickness reduction. The cam clutch unit of the present invention includes: a plurality of cams arranged between an inner race and an outer race; a cage ring having a plurality of pocket portions that restrict relative circumferential movements of the cams; and an annular spring that biases the cams. The cams have an engagement step adapted to engage with the spring on one axial end face. The cage ring has a plurality of hook portions that restrict an axial movement of the annular spring. The hook portions have a pressing part that allows the spring to press the cams towards the other axial end.